Tag Archives: lipid nanoparticle (LNP)

A new lipid nanoparticle (LNP) delivery system for CRISPR-Cas9) gene editing

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The first time lipid nanoparticles were mentioned here as a delivery system for CRISPR-Cas9 editing was in a January 26, 2018 posting featuring work at the Massachusetts Institute of Technology (MIT). This latest research on the topic comes from Japan according to a March 2, 2023 news item on phys.org,

Gene therapy is a potential mode of treatment for a wide variety of diseases caused by genetic mutations. While it has been an area of diverse and intense research, historically, only a very few patients have been treated using gene therapy—and fewer still cured. The advent of the genetic modification technique called CRISPR-Cas9 in 2012 has revolutionized gene therapy—as well as biology as a whole—and it has recently entered clinical trials for the treatment of some diseases in humans.

Haruno Onuma, Yusuke Sato and Hideyoshi Harashima at Hokkaido University have developed a new delivery system for CRISPR-Cas9, based on lipid nanoparticles (LNPs), that could greatly increases the efficiency of in vivo gene therapy. Their findings were published in the Journal of Controlled Release.

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A March 2, 2023 Hokkaido University press release (also on EurekAlert), which originated the news item, provides details about the researchers’ new technique,

“There are broadly two ways of treating diseases with gene therapy,” Sato explained, “ex vivo, where cells are subjected to the desired modifications in the laboratory and then introduced into the patient, and in vivo, where the treatment is administered to the patient to change the cells in their body. Safe and effective in vivo treatment is the ultimate aspiration of gene therapy, as it would be a straightforward process for patients and healthcare providers. LNPs can function as a vehicle for the safe and effective delivery of such therapies.”

CRISPR-Cas9 consists of a large molecule composed of the Cas9 protein and guide RNA. The guide RNA binds to a specific, complementary DNA sequence, and the Cas9 protein cuts that sequence, allowing it to be modified. The guide RNA can be altered to target specific DNA sequences to be modified.

“In a previous study, we discovered that additional DNA molecules, called ssODNs, ensure that the CRISPR-Cas9 molecule is loaded into the LNPs (CRISPR-LNPs),” Harashima elucidated. “In this study,  we again used ssODNs, but they were carefully designed so that they would not inhibit the function of the guide RNA.” 

Using a guide RNA targeting the expression of a protein called transthyretin, they evaluated the effectiveness of the CRISPR-LNPs in mice models. CRISPR-LNPs with ssODNs that dissociated from the guide RNA at room temperature were most effective at reducing serum transthyretin: two consecutive doses, one day apart, reduced it by 80%.

“We have demonstrated the optimal ssODN sequence affinity that ensures the loading and the release of CRISPR-Cas9 at the target location; and that this system can be used to edit cells in vivo,” concluded Onuma. “We will continue to improve the design of ssODNs, as well as to develop optimal lipid formulations to increase the effectiveness of delivery.” 

The image and caption helped me with better understanding the technique described in the press release,

The RNP-ssODN is designed to ensure the CRISPR-Cas9 molecule is encapsulated by the LNP. Once inside the cells, the ssODN dissociates and CRISPR-Cas9 can carry out its effect. (Haruno Onuma, Yusuke Sato, Hideyoshi Harashima. Journal of Controlled Release. February 10, 2023).

Here’s a link to and a citation for the paper,

Lipid nanoparticle-based ribonucleoprotein delivery for in vivo genome editing by Haruno Onuma, Yusuke Sato, Hideyoshi Harashima. Journal of Controlled Release Volume 355, March 2023, Pages 406-416 DOI: https://doi.org/10.1016/j.jconrel.2023.02.008

This paper is behind a paywall.

Gene editing the lungs with nanoparticles

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The nanoparticles in question are lipid nanoparticles designed for delivery to the lungs and they are somewhat similar to the ones in some of the COVID-19 vaccines (mRNA vaccines). From a March 30, 2023 news item on Nanowerk,

Engineers at MIT [Massachusetts Institute of Technology] and the University of Massachusetts Medical School have designed a new type of nanoparticle that can be administered to the lungs, where it can deliver messenger RNA encoding useful proteins.

With further development, these particles could offer an inhalable treatment for cystic fibrosis and other diseases of the lung, the researchers say.

“This is the first demonstration of highly efficient delivery of RNA to the lungs in mice. We are hopeful that it can be used to treat or repair a range of genetic diseases, including cystic fibrosis,” says Daniel Anderson, a professor in MIT’s Department of Chemical Engineering and a member of MIT’s Koch Institute for Integrative Cancer Research and Institute for Medical Engineering and Science (IMES).

In a study of mice, Anderson and his colleagues used the particles to deliver mRNA encoding the machinery needed for CRISPR/Cas9 gene editing. That could open the door to designing therapeutic nanoparticles that can snip out and replace disease-causing genes.

Engineers at MIT and the University of Massachusetts Medical School have designed a new type of nanoparticle that can be administered to the lungs, where it can deliver messenger RNA encoding useful proteins. Credits: Image: iStock, edited by MIT News

A March 30, 2023 MIT news release, also on EurekAlert, which originated the news item, describes the research in more detail,

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Targeting the lungs

Messenger RNA holds great potential as a therapeutic for treating a variety of diseases caused by faulty genes. One obstacle to its deployment thus far has been difficulty in delivering it to the right part of the body, without off-target effects. Injected nanoparticles often accumulate in the liver, so several clinical trials evaluating potential mRNA treatments for diseases of the liver are now underway. RNA-based Covid-19 vaccines, which are injected directly into muscle tissue, have also proven effective. In many of those cases, mRNA is encapsulated in a lipid nanoparticle — a fatty sphere that protects mRNA from being broken down prematurely and helps it enter target cells. 

Several years ago, Anderson’s lab set out to design particles that would be better able to transfect the epithelial cells that make up most of the lining of the lungs. In 2019, his lab created nanoparticles that could deliver mRNA encoding a bioluminescent protein to lung cells. Those particles were made from polymers instead of lipids, which made them easier to aerosolize for inhalation into the lungs. However, more work is needed on those particles to increase their potency and maximize their usefulness. 

In their new study, the researchers set out to develop lipid nanoparticles that could target the lungs. The particles are made up of molecules that contain two parts: a positively charged headgroup and a long lipid tail. The positive charge of the headgroup helps the particles to interact with negatively charged mRNA, and it also help mRNA to escape from the cellular structures that engulf the particles once they enter cells. 

The lipid tail structure, meanwhile, helps the particles to pass through the cell membrane. The researchers came up with 10 different chemical structures for the lipid tails, along with 72 different headgroups. By screening different combinations of these structures in mice, the researchers were able to identify those that were most likely to reach the lungs. 

Efficient delivery

In further tests in mice, the researchers showed that they could use the particles to deliver mRNA encoding CRISPR/Cas9 components designed to cut out a stop signal that was genetically encoded into the animals’ lung cells. When that stop signal is removed, a gene for a fluorescent protein turns on. Measuring this fluorescent signal allows the researchers to determine what percentage of the cells successfully expressed the mRNA.

After one dose of mRNA, about 40 percent of lung epithelial cells were transfected, the researchers found. Two doses brought the level to more than 50 percent, and three doses up to 60 percent. The most important targets for treating lung disease are two types of epithelial cells called club cells and ciliated cells, and each of these was transfected at about 15 percent. 

“This means that the cells we were able to edit are really the cells of interest for lung disease,” Li says. “This lipid can enable us to deliver mRNA to the lung much more efficiently than any other delivery system that has been reported so far.”

The new particles also break down quickly, allowing them to be cleared from the lung within a few days and reducing the risk of inflammation. The particles could also be delivered multiple times to the same patient if repeat doses are needed. This gives them an advantage over another approach to delivering mRNA, which uses a modified version of harmless adenoviruses. Those viruses are very effective at delivering RNA but can’t be given repeatedly because they induce an immune response in the host.

To deliver the particles in this study, the researchers used a method called intratracheal instillation, which is often used as a way to model delivery of medication to the lungs. They are now working on making their nanoparticles more stable, so they could be aerosolized and inhaled using a nebulizer. 

The researchers also plan to test the particles to deliver mRNA that could correct the genetic mutation found in the gene that causes cystic fibrosis, in a mouse model of the disease. They also hope to develop treatments for other lung diseases, such as idiopathic pulmonary fibrosis, as well as mRNA vaccines that could be delivered directly to the lungs.

Here’s a link to and a citation from the paper,

Combinatorial design of nanoparticles for pulmonary mRNA delivery and genome editing by Bowen Li, Rajith Singh Manan, Shun-Qing Liang, Akiva Gordon, Allen Jiang, Andrew Varley, Guangping Gao, Robert Langer, Wen Xue & Daniel Anderson. Nature Biotechnology (2023) DOI: https://doi.org/10.1038/s41587-023-01679-x Published 30 March 2023

This paper is behind a paywall.

Documentary “NNI Retrospective Video: Creating a National Initiative” celebrates the US National Nanotechnology Initiative (NNI) and a lipid nanoparticle question

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i stumbled across an August 4, 2022 tvworldwide.com news release about a video celbrating the US National Nanotechnology Initiative’s (NNI) over 20 years of operation, (Note: A link has been removed),

TV Worldwide, since 1999, a pioneering web-based global TV network, announced that it was releasing a video trailer highlighting a previously released documentary on NNI over the past 20 years, entitled, ‘NNI Retrospective Video: Creating a National Initiative’.

The video and its trailer were produced in cooperation with the National Nanotechnology Initiative (NNI), the National Science Foundation and the University of North Carolina Greensboro.

Video Documentary Synopsis

Nanotechnology is a megatrend in science and technology at the beginning of the 21 Century. The National Nanotechnology Initiative (NNI) has played a key role in advancing the field after it was announced by President Clinton in January 2000. Neil Lane was Presidential Science Advisor. Mike Roco proposed the initiative at the White House in March 1999 on behalf of the Interagency Working Group on Nanotechnology and was named the founding Chair of NSET to implement NNI beginning with Oct. 2000. NSF led the preparation of this initiative together with other agencies including NIH, DoD, DOE, NASA, and EPA. Jim Murday was named the first Director of NNCO to support NSET. The scientific and societal success of NNI has been recognized in the professional communities, National Academies, PCAST, and Congress. Nanoscale science, engineering and technology are strongly connected and collectively called Nanotechnology.

This video documentary was made after the 20th NNI grantees conference at NSF. It is focused on creating and implementing NNI, through video interviews. The interviews focused on three questions: (a) Motivation and how NNI started; (b) The process and reason for the success in creating NNI; (c) Outcomes of NNI after 20 years, and how the initial vision has been realized.

About the National Nanotechnology Initiative (NNI)

The National Nanotechnology Initiative (NNI) is a U.S. Government research and development (R&D) initiative. Over thirty Federal departments, independent agencies, and commissions work together toward the shared vision of a future in which the ability to understand and control matter at the nanoscale leads to ongoing revolutions in technology and industry that benefit society. The NNI enhances interagency coordination of nanotechnology R&D, supports a shared infrastructure, enables leveraging of resources while avoiding duplication, and establishes shared goals, priorities, and strategies that complement agency-specific missions and activities.

The NNI participating agencies work together to advance discovery and innovation across the nanotechnology R&D enterprise. The NNI portfolio encompasses efforts along the entire technology development pathway, from early-stage fundamental science through applications-driven activities. Nanoscience and nanotechnology are prevalent across the R&D landscape, with an ever-growing list of applications that includes nanomedicine, nanoelectronics, water treatment, precision agriculture, transportation, and energy generation and storage. The NNI brings together representatives from multiple agencies to leverage knowledge and resources and to collaborate with academia and the private sector, as appropriate, to promote technology transfer and facilitate commercialization. The breadth of NNI-supported infrastructure enables not only the nanotechnology community but also researchers from related disciplines.

In addition to R&D efforts, the NNI is helping to build the nanotechnology workforce of the future, with focused efforts from K–12 through postgraduate research training. The responsible development of nanotechnology has been an integral pillar of the NNI since its inception, and the initiative proactively considers potential implications and technology applications at the same time. Collectively, these activities ensure that the United States remains not only the place where nanoscience discoveries are made, but also where these discoveries are translated and manufactured into products to benefit society.

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I’m embedding the trailer here and a lipid nanoparticle question follows (The origin story told in Vancouver [Canada] is that the work was started at the University of British Columbia by Pieter Quilty.),

I was curious about what involvement the US NNI had with the development of lipid nanoparticles (LNPs) and found a possible answer to that question on Wikipedia The LNP Wikipedia entry certainly gives the bulk of the credit to Quilty but there was work done prior to his involvement (Note: Links have been removed),

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A significant obstacle to using LNPs as a delivery vehicle for nucleic acids is that in nature, lipids and nucleic acids both carry a negative electric charge—meaning they do not easily mix with each other.[19] While working at Syntex in the mid-1980s,[20] Philip Felgner [emphasis mine] pioneered the use of artificially-created cationic lipids (positively-charged lipids) to bind lipids to nucleic acids in order to transfect the latter into cells.[21] However, by the late 1990s, it was known from in vitro experiments that this use of cationic lipids had undesired side effects on cell membranes.[22]

During the late 1990s and 2000s, Pieter Cullis of the University of British Columbia [emphasis mine] developed ionizable cationic lipids which are “positively charged at an acidic pH but neutral in the blood.”[8] Cullis also led the development of a technique involving careful adjustments to pH during the process of mixing ingredients in order to create LNPs which could safely pass through the cell membranes of living organisms.[19][23] As of 2021, the current understanding of LNPs formulated with such ionizable cationic lipids is that they enter cells through receptor-mediated endocytosis and end up inside endosomes.[8] The acidity inside the endosomes causes LNPs’ ionizable cationic lipids to acquire a positive charge, and this is thought to allow LNPs to escape from endosomes and release their RNA payloads.[8]

From 2005 into the early 2010s, LNPs were investigated as a drug delivery system for small interfering RNA (siRNA) drugs.[8] In 2009, Cullis co-founded a company called Acuitas Therapeutics to commercialize his LNP research [emphasis mine]; Acuitas worked on developing LNPs for Alnylam Pharmaceuticals’s siRNA drugs.[24] In 2018, the FDA approved Alnylam’s siRNA drug Onpattro (patisiran), the first drug to use LNPs as the drug delivery system.[3][8]

By that point in time, siRNA drug developers like Alnylam were already looking at other options for future drugs like chemical conjugate systems, but during the 2010s, the earlier research into using LNPs for siRNA became a foundation for new research into using LNPs for mRNA.[8] Lipids intended for short siRNA strands did not work well for much longer mRNA strands, which led to extensive research during the mid-2010s into the creation of novel ionizable cationic lipids appropriate for mRNA.[8] As of late 2020, several mRNA vaccines for SARS-CoV-2 use LNPs as their drug delivery system, including both the Moderna COVID-19 vaccine and the Pfizer–BioNTech COVID-19 vaccines.[3] Moderna uses its own proprietary ionizable cationic lipid called SM-102, while Pfizer and BioNTech licensed an ionizable cationic lipid called ALC-0315 from Acuitas.[8] [emphases mine]

You can find out more about Philip Felgner here on his University of California at Irvine (UCI) profile page.

I wish they had been a little more careful about some of the claims that Thomas Kalil made about lipid nanoparticles in both the trailer and video but, getting back to the trailer (approx. 3 mins.) and the full video (approx. 25 mins.), either provides insight into a quite extraordinary effort.

Bravo to the US NNI!

Optimizing mRNA nanoparticles

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The process of continuously working on scientific improvements is not always appreciated by outsiders such as myself. A December 28, 2021 news item on Nanowerk highlights research published (from 2019 and 2020) on improving delivery of mRNA used in vaccines (Note: A link has been removed),

The research neutron source Hein Maier-Leibnitz (FRM II) at the Technical University of Munich (TUM) is playing an important role in the investigation of mRNA nanoparticles similar to the ones used in the Covid-19 vaccines from vendors BioNTech and Moderna. Researchers at the Heinz Maier-Leibnitz Zentrum (MLZ) used the high neutron flux available in Garching to characterize various formulations for the mRNA vaccine and thus to lay the groundwork for improving the vaccine’s efficacy.

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A December 27, 2021 TUM press release, which originated the news item, delves further into the science of improving something that already works well,

The idea of using messenger RNA (mRNA) as an active ingredient is a brilliant one: The molecule contains the specific blueprint for proteins which are then synthesize by the cell. This makes it generally possible to provide a very wide spectrum of different therapeutically effective proteins.

In the case of the Covid-19 vaccine, these are the proteins of the characteristic spikes on the surface of the Corona virus which are used for vaccination. The proteins are presented on the surface of immune cells; then the human immune system triggers defenses against these foreign proteins and thus against the Corona virus. The mRNA itself is completely broken down after only a few hours, a fact which is advantageous to the safety of these vaccines.

The road to the best packaging

The mRNA has to be packaged appropriately in order to keep it from being broken down on the way to the cell by the ubiquitous enzymes of the human body. This is done using nanoparticles which can consist of a mixture of lipids or polymers.

The lipids are fat molecules similar to the molecules of the cell membrane and help deposit the mRNA in the interior of the cell. Lipids and biopolymers are then broken down or excreted by the body.

To this ends, the BioNTech formulation team led by Dr. Heinrich Haas worked together with the group led by Prof. Peter Langguth of the Pharmaceutical Technology department at the Johannes Gutenberg University Mainz’s Institute of Pharmaceutical and Biomedical Sciences. They developed a series of formulations in which the nanoparticles consisted of various mixtures of lipids and biopolymers already proved in pharmaceuticals.

In the light of neutrons

In order to compare the properties of variously composed nanoparticles with one another, the researchers subjected the nanoparticles to a wide range of investigations. In addition to x-ray and microscopic analyses, these investigations included radiation with neutrons using the instrument KWS-2, operated by the Forschungszentrum Jülich at the FRM II of the Technical University of Munich in Garching.

The neutrons are scattered in the interior of the nanoparticles, inter alia, on the hydrogen nuclei and are deflected from their paths in a characteristic way. This is the basis for conclusions about their distribution. If the hydrogen atoms of certain components – for example of the lipids only – are exchanged with heavy hydrogen, the chemical properties and the pharmaceutical efficacy do not change, but the scattering pattern of the neutrons does.

“This method makes it possible to selectively highlight parts of a complex multi-component morphology without changing the physical chemistry of the sample,” says Dr. Aurel Radulescu of the Jülich Centre for Neutron Science (JCNS), who is responsible for the instrument KWS-2 and who led the evaluation of the measurement results. “This makes it possible to depict structural properties which other methods can only barely render visible, if at all.”

The right degree of order is the key

In these analyses the research teams were interested in how efficiently the various formulations were able to transmit the mRNA into the cell, referred to as transfection. The researchers thus found out that the highest transfection rates were achieved with nanoparticles that are characterized by a certain type of internal arrangement.

“High levels of biological activity were registered whenever ordered and less ordered areas alternated in the interior of the nanoparticles in a characteristic manner. This could be a generally valid concept of structure-activity relationship which can be applied independently of the systems investigated here,” Dr. Heinrich Haas of BioNTech points out. A similarly low degree of order had also been found previously by the research teams using x-ray radiation in other lipid nanoparticles.

An improved procedure

In order to receive the desired structural properties lipids and biopolymers had to be combined with the mRNA using exactly defined procedures. Here the research team was able to show that the nanoparticles for packaging the mRNA could be produced in a single step, which means a significant simplification compared to the two-step procedure which was originally also investigated.

Thus a simplified method for the creation of mRNA nanoparticles with improved activity was ultimately found. “Such questions of practical producibility represent an important prerequisite for the possibility of developing pharmaceutical products,” says Prof. Langguth. In the future such concepts could be taken into account in the development of new mRNA-based therapeutic agents.

Here are links to and citations for the papers (Note: This is not my usual way of setting the links),

Hybrid Biopolymer and Lipid Nanoparticles with Improved Transfection Efficacy for mRNA by Christian D. Siewert, Heinrich Haas, Vera Cornet, Sara S. Nogueira, Thomas Nawroth, Lukas Uebbing, Antje Ziller, Jozef Al-Gousous, Aurel Radulescu, Martin A. Schroer, Clement E. Blanchet, Dmitri I. Svergun, Markus P. Radsak, Ugur Sahin and Peter Langguth. Cells 2020, 9(9), 2034 – DOI: 10.3390/cells9092034

This paper appears to be open access.

Investigation of charge ratio variation in mRNA – DEAE-dextran polyplex delivery systems by C. Siewert, H. Haas, T. Nawroth, A. Ziller, S. S. Nogueira, M. A. Schroer, C. E. Blanchet, D. I. Svergun, A. Radulescu, F. Bates, Y. Huesemann, M. P. Radsak, U. Sahin, P. Langguth. Biomaterials, 2019; DOI: 10.1016/j.biomaterials.2018.10.020

This paper is open access.

Polysarcosine-Functionalized Lipid Nanoparticles for Therapeutic mRNA Delivery by S S. Nogueira, A. Schlegel, K. Maxeiner, B. Weber, M. Barz, M. A. Schroer, C. E. Blanchet, D. I. Svergun, S. Ramishetti, D. Peer, P. Langguth, U. Sahin, H. Haas. ACS Appl. Nano Mater. 2020, 3, 11, 10634–10645 – DOI: 10.1021/acsanm.0c01834

This paper is behind a paywall.

Getting erased from the mRNA/COVID-19 story

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Nathan Vardi’s August 17, 2021 article for Forbes magazine about Ian MacLachlan and the delivery system for mRNA vaccines tells a type of story I’ve more often seen in history books. It is reminiscent of the Thomas Edison and Nikola Tesla story of electricity. One gets all the glory while the other is largely forgotten.

I’m especially interested as much of this concerns players in the local (Vancouver, British Columbia, Canada) biotechnology scene. Vardi’s August 17, 2021 article sets the scene,

“The whole mRNA platform is not how to build an mRNA molecule; that’s the easy thing,” Bourla [Pfizer CEO Albert Bourla] says. “It is how to make sure the mRNA molecule will go into your cells and give the instructions.” 

Yet the story of how Moderna, BioNTech and Pfizer managed to create that vital delivery system has never been told. It’s a complicated saga involving 15 years of legal battles and accusations of betrayal and deceit. [emphases mine] What is clear is that when humanity needed a way to deliver mRNA to human cells to arrest the pandemic, there was only one reliable method available—and it wasn’t one originated in-house by Pfizer, Moderna, BioNTech or any of the other major vaccine companies. 

A months-long investigation by Forbes reveals that the scientist most responsible for this critical delivery method is a little-known 57-year-old Canadian biochemist named Ian MacLachlan. As chief scientific officer of two small companies, Protiva Biotherapeutics and Tekmira Pharmaceuticals, MacLachlan led the team that developed this crucial technology. Today, though, few people—and none of the big pharmaceutical companies—openly acknowledge his groundbreaking work, and MacLachlan earns nothing from the technology he pioneered. 

I have three stories (on this blog) mentioning Tekmira (all from 2014 or 2015) and none mentioning Protiva nor, for that matter, Ian MacLachlan.

Back to Vardi’s August 17, 2021 article,

Moderna Therapeutics vigorously disputes the idea that its mRNA vaccine uses MacLachlan’s delivery system, and BioNTech, the vaccine maker partnered with Pfizer, talks about it carefully. Legal proceedings are pending, and big money is at stake. 

Moderna, BioNTech and Pfizer are on their way to selling $45 billion worth of vaccines in 2021. They don’t pay a dime to MacLachlan. Other coronavirus vaccine makers, such as Gritstone Oncology, have recently licensed MacLachlan’s Protiva-Tekmira delivery technology for between 5% and 15% of product sales. MacLachlan no longer has a financial stake in the technology, but a similar royalty on the Moderna and Pfizer-BioNTech vaccines could yield as much as $6.75 billion in 2021 alone. …

Vardi provides evidence (Note: A link has been removed from the August 17, 2021 article excerpt,

Despite their denials, scientific papers and regulatory documents filed with the FDA [US Food and Drug Administration] show that both Moderna and Pfizer-BioNTech’s vaccines use a delivery system strikingly similar to what MacLachlan and his team created—a carefully formulated four-lipid component that encapsulates mRNA in a dense particle through a mixing process involving ethanol and a T-connector apparatus. 

For years, Moderna claimed it was using its own proprietary delivery system, but when it came time for the company to test its Covid-19 vaccine in mice, it used the same four kinds of lipids as MacLachlan’s technology, in identical ratios. 

According to Vardi’s LinkedIn profile: “I am a senior editor at Forbes, where I am responsible for the coverage of hedge funds, private equity, and other big investors. I lead investigative reporting efforts and have written 20 cover stories for Forbes Magazine,” he does not appear to have any medical or bioscience expertise (Bachelor of Journalism from Carleton University [Canada] and Masters of International Affairs from Columbia University [US].) Presumably someone he consulted or someone on his team provided the skills necessary for analyzing the scientific papers and documents.

You may recognize this scientist (from the August 17, 2021 article),

Not everyone ignores MacLachlan. “A lot of credit goes to Ian MacLachlan for the LNP [lipid nanoparticle],” says Katalin Karikó, [emphasis mine] the scientist who laid the groundwork for mRNA therapies before joining BioNTech in 2013. But Karikó, now a frontrunner for a Nobel Prize, is angry that MacLachlan didn’t do more to help her use his delivery system to build her own mRNA company years ago. “[MacLachlan] might be a great scientist, but he lacked vision,” she says.

I have more about Karikó and her role in the mRNA vaccine story here in a March 5, 2021 posting.

As for MacLachlan’s start (from the August 17, 2021 article),

… With a Ph.D. in biochemistry, MacLachlan joined Inex in 1996, his first job after completing a postdoctoral fellowship in a gene lab at the University of Michigan. 

Inex was cofounded by its chief scientific officer, Pieter Cullis, now 75, a long-haired physicist who taught at the University of British Columbia. From his perch there Cullis started several biotechs, cultivating an elite community of scientists that made Vancouver a hotbed of lipid chemistry. 

As companies rise and fall with intellectual property being assigned to one company or other, legal brawls ensue. This was the time that Karikó came knocking on the door, from the August 17, 2021 article,

It was in the midst of all this furious legal fighting that Hungarian biochemist Katalin Karikó first showed up at MacLachlan’s door. Karikó was early to grasp that MacLachlan’s delivery system held the key to unlocking the potential of mRNA therapies. As early as 2006, she began sending letters to MacLachlan urging him to encase her groundbreaking chemically altered mRNA in his four-lipid delivery system. Embroiled in litigation, MacLachlan passed on her offer. 

Karikó didn’t give up easily. In 2013, she flew to meet with Tekmira’s executives, offering to relocate to Vancouver and work directly under MacLachlan. Tekmira passed. “Moderna, BioNTech and CureVac all wanted me to work for them, but my number one choice, Tekmira, didn’t,” says Karikó, who took a job at BioNTech in 2013. 

By this time, Moderna CEO Stéphane Bancel [emphasis mine] was also trying to solve the delivery puzzle. Bancel held discussions with Tekmira about collaborating, but talks stalled. At one point, Tekmira indicated it wanted at least $100 million up front, plus royalties, to strike a deal.

Instead, Moderna partnered with Madden [Thomas Madden], who was still working with Cullis at their drug delivery company, Acuitas Therapeutics.  …

I have been wondering why Acuitas Therapeutics hasn’t been getting all that much attention in the hyperbolic discussions about British Columbia’s (or Vancouver’s) thriving biotechnology scene. (I’ll have more about the ‘scene’ in a later posting.) Perhaps all this legal wrangling is not considered helpful when bragging. (I do have a November 12, 2020 post, which features Acuitas, an interview with its president and chief executive office Dr. Thomas Madden, and an explanation of their technology.)

As for Moderna, I have a special interest as the company has announced plans to open a production facility here in Canada and one of Moderna’s founders is Canadian, Derek Rossi. (He too is mentioned in the March 5, 2021 posting, scroll down to the ‘Entrepreneurs rush in’ subhead; he is not an altogether happy camper.)

Rossi has opinions on how we should be doing things here as noted in a June 17, 2021 article by Barbara Shecter for the Financial Post (Moderna founder says Canada needs to build a biotech hub to avoid ‘getting caught with its pants down next time’). Thank you, Mr. Rossi. (I’m more familiar with clusters than hubs [hubs were a popular topic of conversation about 20 years ago but in Canada we seem more interested in clusters; see John Newbigin’s “Hubs, clusters and regions” on britishcouncil.org for a description of the differences].)

As for Moderna’s response to all of the legal wrangling over mRNA delivery systems, from Vardi’s August 17, 2021 article,

Moderna pursued a different strategy. It filed lawsuits with the U.S. Patent and Trademark Office seeking to nullify a series of patents related to MacLachlan’s delivery system, now controlled by Genevant. But in July 2020, as Moderna was pushing its vaccine through clinical trials, an adjudicative body largely upheld the most important patent claims. (Moderna is appealing.)

I highly recommend reading Vardi’s August 17, 2021 article as I have not done justice to all of the ‘ins and outs’ of the story.

You can see how thoroughly MacLachlan has been erased form the lipid nanoparticle delivery system/COVID-19 vaccine story in this May 24 ,2021 posting (Lipid nanoparticles: The underrated invention behind the vaccine revolution) by Nada Salem at the Science Borealis blog. It is largely a description of the technology and in the last two paragraphs a history of its development with no mention of MacLachlan or any of his companies.

One last thought, I wonder how Vardi found out about MacLachlan. Could someone have brought the story to his attention and who might that have been?

Precision targeting of the liver for gene editing

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Apparently the magic is in the lipid nanoparticles. A March 1, 2021 news item on Nanowerk announced research into lipid nanoparticles as a means to deliver CRISPR (clustered regularly interspaced short palindromic repeats) to specific organs (Note: A link has been removed),

The genome editing technology CRISPR has emerged as a powerful new tool that can change the way we treat disease. The challenge when altering the genetics of our cells, however, is how to do it safely, effectively, and specifically targeted to the gene, tissue and organ that needs treatment.

Scientists at Tufts University and the Broad Institute of Harvard [University] and MIT [Massachusetts Institute of Technology] have developed unique nanoparticles comprised of lipids — fat molecules — that can package and deliver gene editing machinery specifically to the liver.

In a study published in the Proceedings of the National Academy of Sciences [PNAS] (“Lipid nanoparticle-mediated codelivery of Cas9 mRNA and single-guide RNA achieves liver-specific in vivo genome editing of Angptl3”), they have shown that they can use the lipid nanoparticles (LNPs) to efficiently deliver the CRISPR machinery into the liver of mice, resulting in specific genome editing and the reduction of blood cholesterol levels by as much as 57% — a reduction that can last for at least several months with just one shot.

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A March 2, 2021 Tufts University news release (also on EurekAlert but published March 1, 2021), which originated the news item, provides greater insight into and technical detail about the research,

The problem of high cholesterol plagues more than 29 million Americans, according to the Centers for Disease Control and Prevention. The condition is complex and can originate from multiple genes as well as nutritional and lifestyle choices, so it is not easy to treat. The Tufts and Broad researchers, however, have modified one gene that could provide a protective effect against elevated cholesterol if it can be shut down by gene editing.

The gene that the researchers focused on codes for the angiopoietin-like 3 enzyme (Angptl3). That enzyme tamps down the activity of other enzymes – lipases – that help break down cholesterol. If researchers can knock out the Angptl3 gene, they can let the lipases do their work and reduce levels of cholesterol in the blood. It turns out that some lucky people have a natural mutation in their Angptl3 gene, leading to consistently low levels of triglycerides and low-density lipoprotein (LDL) cholesterol, commonly called “bad” cholesterol, in their bloodstream without any known clinical downsides.

“If we can replicate that condition by knocking out the angptl3 gene in others, we have a good chance of having a safe and long term solution to high cholesterol,” said Qiaobing Xu, associate professor of biomedical engineering at Tufts’ School of Engineering and corresponding author of the study. “We just have to make sure we deliver the gene editing package specifically to the liver so as not to create unwanted side effects.”

Xu’s team was able to do precisely that in mouse models. After a single injection of lipid nanoparticles packed with mRNA coding for CRISPR-Cas9 and a single-guide RNA targeting Angptl3, they observed a profound reduction in LDL cholesterol by as much as 57% and triglyceride levels by about 29 %, both of which remained at those lowered levels for at least 100 days. The researchers speculate that the effect may last much longer than that, perhaps limited only by the slow turnover of cells in the liver, which can occur over a period of about a year. The reduction of cholesterol and triglycerides is dose dependent, so their levels could be adjusted by injecting fewer or more LNPs in the single shot, the researchers said.

By comparison, an existing, FDA [US Food and Drug Administration]-approved version of CRISPR mRNA-loaded LNPs could only reduce LDL cholesterol by at most 15.7% and triglycerides by 16.3% when it was tested in mice, according to the researchers.

The trick to making a better LNP was in customizing the components – the molecules that come together to form bubbles around the mRNA. The LNPs are made up of long chain lipids that have a charged or polar head that is attracted to water, a carbon chain tail that points toward the middle of the bubble containing the payload, and a chemical linker between them. Also present are polyethylene glycol, and yes, even some cholesterol – which has a normal role in lipid membranes to make them less leaky – to hold their contents better.

The researchers found that the nature and relative ratio of these components appeared to have profound effects on the delivery of mRNA into the liver, so they tested LNPs with many combinations of heads, tails, linkers and ratios among all components for their ability to target liver cells. Because the in vitro potency of an LNP formulation rarely reflects its in vivo performance, they directly evaluated the delivery specificity and efficacy in mice that have a reporter gene in their cells that lights up red when genome editing occurs. Ultimately, they found a CRISPR mRNA-loaded LNP that lit up just the liver in mice, showing that it could specifically and efficiently deliver gene-editing tools into the liver to do their work.

The LNPs were built upon earlier work at Tufts, where Xu and his team developed LNPs with as much as 90% efficiency in delivering mRNA into cells. A unique feature of those nanoparticles was the presence of disulfide bonds between the long lipid chains. Outside the cells, the LNPs form a stable spherical structure that locks in their contents. When they are inside a cell, the environment within breaks the disulfide bonds to disassemble the nanoparticles. The contents are then quickly and efficiently released into the cell. By preventing loss outside the cell, the LNPs can have a much higher yield in delivering their contents.

“CRISPR is one of the most powerful therapeutic tools for the treatment of diseases with a genetic etiology. We have recently seen the first human clinical trail for CRISPR therapy enabled by LNP delivery to be administered systemically to edit genes inside the human body. Our LNP platform developed here holds great potential for clinical translation,” said Min Qiu, post-doctoral researcher in Xu’s lab at Tufts.  “We envision that with this LNP platform in hand, we could now make CRISPR a practical and safe approach to treat a broad spectrum of liver diseases or disorders,” said Zachary Glass, graduate student in the Xu lab. Qiu and Glass are co-first authors of the study.

Here’s a link to and a citation for the paper,

Lipid nanoparticle-mediated codelivery of Cas9 mRNA and single-guide RNA achieves liver-specific in vivo genome editing of Angptl3 by Min Qiu, Zachary Glass, Jinjin Chen, Mary Haas, Xin Jin, Xuewei Zhao, Xuehui Rui, Zhongfeng Ye, Yamin Li, Feng Zhang, and Qiaobing Xu. PNAS March 9, 2021 118 (10) e2020401118 DOI: https://doi.org/10.1073/pnas.2020401118

This paper appears to be behind a paywall.

mRNA, COVID-19 vaccines, treating genetic diseases before birth, and the scientist who started it all

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This post was going to be about new research into fetal therapeutics and mRNA.But, since I’ve been very intrigued by the therapeutic agent, mRNA, which has been a big part of the COVID-19 vaccine story; this seemed like a good opportunity to dive a little more deeply into that topic at the same time.

It’s called messenger ribonucleic acid (mRNA) and until seeing this video I had only the foggiest idea of how it works, which is troubling since at least two COVID-19 vaccines are based on this ‘new’ technology. From a November 10, 2020 article by Damian Garde for STAT,

Garde’s article offers detail about mRNA along with fascinating insight into how science and entreneurship works.

mRNA—it’s in the details, plus, the loneliness of pioneer researchers, a demotion, and squabbles

Garde’s November 10, 2020 article provides some explanation about how mRNA vaccines work and it takes a look at what can happen to pioneering scientists (Note: A link has been removed),

For decades, scientists have dreamed about the seemingly endless possibilities of custom-made messenger RNA, or mRNA.

Researchers understood its role as a recipe book for the body’s trillions of cells, but their efforts to expand the menu have come in fits and starts. The concept: By making precise tweaks to synthetic mRNA and injecting people with it, any cell in the body could be transformed into an on-demand drug factory. [emphasis mine]

But turning scientific promise into medical reality has been more difficult than many assumed. Although relatively easy and quick to produce compared to traditional vaccine-making, no mRNA vaccine or drug has ever won approval [until 2021].

…

Whether mRNA vaccines succeed or not, their path from a gleam in a scientist’s eye to the brink of government approval has been a tale of personal perseverance, eureka moments in the lab, soaring expectations — and an unprecedented flow of cash into the biotech industry.

…

Before messenger RNA was a multibillion-dollar idea, it was a scientific backwater. And for the Hungarian-born scientist behind a key mRNA discovery, it was a career dead-end.

Katalin Karikó spent the 1990s collecting rejections. Her work, attempting to harness the power of mRNA to fight disease, was too far-fetched for government grants, corporate funding, and even support from her own colleagues.

It all made sense on paper. In the natural world, the body relies on millions of tiny proteins to keep itself alive and healthy, and it uses mRNA to tell cells which proteins to make. If you could design your own mRNA, you could, in theory, hijack that process and create any protein you might desire — antibodies to vaccinate against infection, enzymes to reverse a rare disease, or growth agents to mend damaged heart tissue.

In 1990, researchers at the University of Wisconsin managed to make it work in mice. Karikó wanted to go further.

The problem, she knew, was that synthetic RNA was notoriously vulnerable to the body’s natural defenses, meaning it would likely be destroyed before reaching its target cells. And, worse, the resulting biological havoc might stir up an immune response that could make the therapy a health risk for some patients.

It was a real obstacle, and still may be, but Karikó was convinced it was one she could work around. Few shared her confidence.

“Every night I was working: grant, grant, grant,” Karikó remembered, referring to her efforts to obtain funding. “And it came back always no, no, no.”

By 1995, after six years on the faculty at the University of Pennsylvania, Karikó got demoted. She had been on the path to full professorship, but with no money coming in to support her work on mRNA, her bosses saw no point in pressing on.

She was back to the lower rungs of the scientific academy.

“Usually, at that point, people just say goodbye and leave because it’s so horrible,” Karikó said.

There’s no opportune time for demotion, but 1995 had already been uncommonly difficult. Karikó had recently endured a cancer scare, and her husband was stuck in Hungary sorting out a visa issue. Now the work to which she’d devoted countless hours was slipping through her fingers.

“I thought of going somewhere else, or doing something else,” Karikó said. “I also thought maybe I’m not good enough, not smart enough. I tried to imagine: Everything is here, and I just have to do better experiments.”

In time, those better experiments came together. After a decade of trial and error, Karikó and her longtime collaborator at Penn — Drew Weissman, an immunologist with a medical degree and Ph.D. from Boston University — discovered a remedy for mRNA’s Achilles’ heel.

The stumbling block, as Karikó’s many grant rejections pointed out, was that injecting synthetic mRNA typically led to that vexing immune response; the body sensed a chemical intruder, and went to war. The solution, Karikó and Weissman discovered, was the biological equivalent of swapping out a tire.

Every strand of mRNA is made up of four molecular building blocks called nucleosides. But in its altered, synthetic form, one of those building blocks, like a misaligned wheel on a car, was throwing everything off by signaling the immune system. So Karikó and Weissman simply subbed it out for a slightly tweaked version, creating a hybrid mRNA that could sneak its way into cells without alerting the body’s defenses.

“That was a key discovery,” said Norbert Pardi, an assistant professor of medicine at Penn and frequent collaborator. “Karikó and Weissman figured out that if you incorporate modified nucleosides into mRNA, you can kill two birds with one stone.”

That discovery, described in a series of scientific papers starting in 2005, largely flew under the radar at first, said Weissman, but it offered absolution to the mRNA researchers who had kept the faith during the technology’s lean years. And it was the starter pistol for the vaccine sprint to come.

…

Entrepreneurs rush in

Garde’s November 10, 2020 article shifts focus from Karikó, Weissman, and specifics about mRNA to the beginnings of what might be called an entrepreneurial gold rush although it starts sedately,

Derrick Rossi [emphasis mine], a native of Toronto who rooted for the Maple Leafs and sported a soul patch, was a 39-year-old postdoctoral fellow in stem cell biology at Stanford University in 2005 when he read the first paper. Not only did he recognize it as groundbreaking, he now says Karikó and Weissman deserve the Nobel Prize in chemistry.

“If anyone asks me whom to vote for some day down the line, I would put them front and center,” he said. “That fundamental discovery is going to go into medicines that help the world.”

But Rossi didn’t have vaccines on his mind when he set out to build on their findings in 2007 as a new assistant professor at Harvard Medical School running his own lab.

He wondered whether modified messenger RNA might hold the key to obtaining something else researchers desperately wanted: a new source of embryonic stem cells [emphasis mine].

In a feat of biological alchemy, embryonic stem cells can turn into any type of cell in the body. That gives them the potential to treat a dizzying array of conditions, from Parkinson’s disease to spinal cord injuries.

But using those cells for research had created an ethical firestorm because they are harvested from discarded embryos.

Rossi thought he might be able to sidestep the controversy. He would use modified messenger molecules to reprogram adult cells so that they acted like embryonic stem cells.

He asked a postdoctoral fellow in his lab to explore the idea. In 2009, after more than a year of work, the postdoc waved Rossi over to a microscope. Rossi peered through the lens and saw something extraordinary: a plate full of the very cells he had hoped to create.

Rossi excitedly informed his colleague Timothy Springer, another professor at Harvard Medical School and a biotech entrepreneur. Recognizing the commercial potential, Springer contacted Robert Langer, the prolific inventor and biomedical engineering professor at the Massachusetts Institute of Technology.

On a May afternoon in 2010, Rossi and Springer visited Langer at his laboratory in Cambridge. What happened at the two-hour meeting and in the days that followed has become the stuff of legend — and an ego-bruising squabble.

Langer is a towering figure in biotechnology and an expert on drug-delivery technology. At least 400 drug and medical device companies have licensed his patents. His office walls display many of his 250 major awards, including the Charles Stark Draper Prize, considered the equivalent of the Nobel Prize for engineers.

As he listened to Rossi describe his use of modified mRNA, Langer recalled, he realized the young professor had discovered something far bigger than a novel way to create stem cells. Cloaking mRNA so it could slip into cells to produce proteins had a staggering number of applications, Langer thought, and might even save millions of lives.

“I think you can do a lot better than that,” Langer recalled telling Rossi, referring to stem cells. “I think you could make new drugs, new vaccines — everything.”

…

Within several months, Rossi, Langer, Afeyan [Noubar Afeyan, venture capitalist, founded and runs Flagship Ventures], and another physician-researcher at Harvard formed the firm Moderna — a new word combining modified and RNA.

Springer was the first investor to pledge money, Rossi said. In a 2012 Moderna news release, Afeyan said the firm’s “promise rivals that of the earliest biotechnology companies over 30 years ago — adding an entirely new drug category to the pharmaceutical arsenal.”

But although Moderna has made each of the founders hundreds of millions of dollars — even before the company had produced a single product — Rossi’s account is marked by bitterness. In interviews with the [Boston] Globe in October [2020], he accused Langer and Afeyan of propagating a condescending myth that he didn’t understand his discovery’s full potential until they pointed it out to him.

…

Garde goes on to explain how BioNTech came into the mRNA picture and contrasts the two companies’ approaches to biotechnology as a business. It seems BioNTech has not cashed in the same way as has Moderna. (For some insight into who’s making money from COVID-19 check out Giacomo Tognini’s December 23, 2020 article (Meet The 50 Doctors, Scientists And Healthcare Entrepreneurs Who Became Pandemic Billionaires In 2020) for Forbes.)

Garde ends his November 10, 2020 article on a mildly cautionary note,

“You have all these odd clinical and pathological changes caused by this novel bat coronavirus [emphasis mine], and you’re about to meet it with all of these vaccines with which you have no experience,” said Paul Offit, an infectious disease expert at Children’s Hospital of Philadelphia and an authority on vaccines.

What happened to Katalin Karikó?

Matthew Rosza’s January 25, 2021 article about Karikó and her pioneering work features an answer to my question and some advice,

“I want young people to feel — if my example, because I was demoted, rejected, terminated, I was even subject for deportation one point — [that] if they just pursue their thing, my example helps them to wear rejection as a badge,” Karikó, who today is a senior vice president at BioNTech RNA Pharmaceuticals, told Salon last month when discussing her story. “‘Okay, well, I was rejected. I know. Katalin was rejected and still [succeeded] at the end.’ So if it helps them, then it helps them.”

Despite her demotion, Karikó continued with her work and, along with a fellow immunologist named Dr. Drew Weissman, penned a series of influential articles starting in 2005. These articles argued that mRNA vaccines would not be neutralized by the human immune system as long as there were specific modifications to nucleosides, a compound commonly found in RNA.

By 2013, Karikó’s work had sufficiently impressed experts that she left the University of Pennsylvania for BioNTech RNA Pharmaceuticals.

Karikó tells Salon that the experience taught her one important lesson: In life there will be people who, for various reasons, will try to hold you back, and you can’t let them get you down.

“People that are in power, they can help you or block you,” Karikó told Salon. “And sometimes people select to make your life miserable. And now they cannot be happy with me because now they know that, ‘Oh, you know, we had the confrontation and…’ But I don’t spend too much time on these things.”

…

Before moving onto the genetic research which prompted this posting, I have an answer to the following questions:

Could an mRNA vaccine affect your DNA (deoxyribonucleic acid) and how do mRNA vaccines differ from the traditional ones?

No, DNA is not affected by the COVID-19 mRNA vaccines, according to a January 5, 2021 article by Jason Murdock for Newsweek,

The type of vaccines used against COVID-19 do not interact with or alter human genetic code, also known as DNA, scientists say.

…

In traditional vaccines, a piece of a virus, known as an “antigen,” would be injected into the body to force the immune system to make antibodies to fight off future infection. But mRNA-based methods do not use a live virus, and cannot give someone COVID.

Instead, mRNA vaccines give cells the instructions to make a “spike” protein also found on the surface of the virus that causes COVID. The body kickstarts its immune response by creating the antibodies needed to combat those specific virus proteins.

Once the spike protein is created, the cell breaks down the instructions provided by the mRNA molecule, leaving the human immune system prepared to combat infection. The mRNA vaccines are not a medicine—nor a cure—but a preventative measure.

Gavi, a vaccine alliance partnered with the World Health Organization (WHO), has said that mRNA instructions will become degraded in approximately 72 hours.

It says mRNA strands are “chemical intermediaries” between DNA in our chromosomes and the “cellular machinery that produces the proteins we need to function.”

But crucially, while mRNA vaccines will give the human body the blueprints on how to assemble proteins, the alliance said in a fact-sheet last month that “mRNA isn’t the same as DNA, and it can’t combine with our DNA to change our genetic code.”

It explained: “Some viruses like HIV can integrate their genetic material into the DNA of their hosts, but this isn’t true of all viruses… mRNA vaccines don’t carry these enzymes, so there is no risk of the genetic material they contain altering our DNA.”

The [US] Centers for Disease Control and Prevention (CDC) says on its website that mRNA vaccines that are rolling out don’t “interact with our DNA in any way,” and “mRNA never enters the nucleus of the cell, which is where our DNA (genetic material) is kept.”

…

Therapeutic fetal mRNA treatment

Rossi’s work on mRNA and embryonic stem cells bears a relationship of sorts to this work focusing on prebirth therapeutics. (From a January 13, 2021 news item on Nanowerk), Note: A link has been removed,

Researchers at Children’s Hospital of Philadelphia and the School of Engineering and Applied Science at the University of Pennsylvania have identified ionizable lipid nanoparticles that could be used to deliver mRNA as part of fetal therapy.

The proof-of-concept study, published in Science Advances (“Ionizable Lipid Nanoparticles for In Utero mRNA Delivery”), engineered and screened a number of lipid nanoparticle formulations for targeting mouse fetal organs and has laid the groundwork for testing potential therapies to treat genetic diseases before birth.

…

A January 13, 2021 Children’s Hospital of Philadelphia (CHOP) news release (also on EurekAlert), which originated the news item, delves further into the research,

“This is an important first step in identifying nonviral mediated approaches for delivering cutting-edge therapies before birth,” said co-senior author William H. Peranteau, MD, an attending surgeon in the Division of General, Thoracic and Fetal Surgery and the Adzick-McCausland Distinguished Chair in Fetal and Pediatric Surgery at CHOP. “These lipid nanoparticles may provide a platform for in utero mRNA delivery, which would be used in therapies like fetal protein replacement and gene editing.”

…

Recent advances in DNA sequencing technology and prenatal diagnostics have made it possible to diagnose many genetic diseases before birth. Some of these diseases are treated by protein or enzyme replacement therapies after birth, but by then, some of the damaging effects of the disease have taken hold. Thus, applying therapies while the patient is still in the womb has the potential to be more effective for some conditions. The small fetal size allows for maximal therapeutic dosing, and the immature fetal immune system may be more tolerant of replacement therapy.

Of the potential vehicles for introducing therapeutic protein replacement, mRNA is distinct from other nucleic acids, such as DNA, because it does not need to enter the nucleus and can use the body’s own machinery to produce the desired proteins. Currently, the common methods of nucleic acid delivery include viral vectors and nonviral approaches. Although viral vectors may be well-suited to gene therapy, they come with the potential risk of unwanted integration of the transgene or parts of the viral vector in the recipient genome. Thus, there is an important need to develop safe and effective nonviral nucleic acid delivery technologies to treat prenatal diseases.

In order to identify potential nonviral delivery systems for therapeutic mRNA, the researchers engineered a library of lipid nanoparticles, small particles less than 100 nanometers in size that effectively enter cells in mouse fetal recipients. Each lipid nanoparticle formulation was used to encapsulate mRNA, which was administered to mouse fetuses. The researchers found that several of the lipid nanoparticles enabled functional mRNA delivery to fetal livers and that some of those lipid nanoparticles also delivered mRNA to the fetal lungs and intestines. They also assessed the lipid nanoparticles for toxicity and found them to be as safe or safer than existing formulations.

Having identified the lipid nanoparticles that were able to accumulate within fetal livers, lungs, and intestines with the highest efficiency and safety, the researchers also tested therapeutic potential of those designs by using them to deliver erythropoietin (EPO) mRNA, as the EPO protein is easily trackable. They found that EPO mRNA delivery to liver cells in mouse fetuses resulted in elevated levels of EPO protein in the fetal circulation, providing a model for protein replacement therapy via the liver using these lipid nanoparticles.

“A central challenge in the field of gene therapy is the delivery of nucleic acids to target cells and tissues, without causing side effects in healthy tissue. This is difficult to achieve in adult animals and humans, which have been studied extensively. Much less is known in terms of what is required to achieve in utero nucleic acid delivery,” said Mitchell. “We are very excited by the initial results of our lipid nanoparticle technology to deliver mRNA in utero in safe and effective manner, which could open new avenues for lipid nanoparticles and mRNA therapeutics to treat diseases before birth.”

Here’s a link to and a citation for the paper,

Ionizable lipid nanoparticles for in utero mRNA delivery by Rachel S. Riley, Meghana V. Kashyap, Margaret M. Billingsley, Brandon White, Mohamad-Gabriel Alameh, Sourav K. Bose, Philip W. Zoltick, Hiaying Li, Rui Zhang, Andrew Y. Cheng, Drew Weissman, William H. Peranteau, Michael J. Mitchell. Science Advances 13 Jan 2021: Vol. 7, no. 3, eaba1028 DOI: 10.1126/sciadv.aba1028

This paper appears to be open access. BTW, I noticed Drew Weissman’s name as one of the paper’s authors and remembered him as one of the first to recognize Karikó’s pioneering work. I imagine that when he co-authored papers with Karikó he was risking his reputation.

Funny how a despised field of research has sparked a ‘gold rush’ for research and for riches, yes?.

RNA interference: a Tekmira deal and a new technique births Solstice Biologics

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I have two news items concerning ribonucleic acid interference (RNAi). The first item features Tekmira Pharmaceuticals Corporation (a Canadian company located in the Vancouver area) and a licencing deal with Dicerna Pharmaceuticals (Massachusetts, US), according to a Nov. 18, 2014 news item on Azonano,

Tekmira Pharmaceuticals Corporation a leading developer of RNA interference (RNAi) therapeutics, today announces a licensing and collaboration agreement with Dicerna Pharmaceuticals, Inc. Tekmira has licensed its proprietary lipid nanoparticle (LNP) delivery technology for exclusive use in Dicerna’s primary hyperoxaluria type 1 (PH1) development program.

Under the agreement, Dicerna will pay Tekmira $2.5 million upfront and payments of $22 million in aggregate development milestones, plus a mid-single-digit royalty on future PH1 sales. This new partnership also includes a supply agreement with Tekmira providing clinical drug supply and regulatory support in the rapid advancement of the product candidate.

The agreement announced today follows the successful testing and demonstration of positive results combining Tekmira’s LNP technology with DCR-PH1 in pre-clinical animal models.

I don’t entirely understand what they mean by “pre-clinical animal models” as I’ve not noticed the term “pre-clinical” applied to animal testing before this. It’s possible they mean they’ve run tests on animals (in vivo) and are now proceeding to human clinical trials or it could mean they’ve run in silico (computer modeling) or in vitro (test tube/test slide) tests and are now proceeding to animal tests. If anyone should have some insights, please do share them with me in the comments section.

A Nov. 17, 2014 Tekmira news release, which originated the news item, describes the deal in more detail,

Dicerna will use Tekmira’s third generation LNP technology for delivery of DCR-PH1, Dicerna’s Dicer substrate RNA (DsiRNA) molecule, for the treatment of PH1, a rare, inherited liver disorder that often results in kidney failure and for which there are no approved therapies.

“This new agreement validates our leadership position in RNAi delivery with LNP technology, and it underscores the significant value we can bring to partners who leverage our technology. Our LNP technology is enabling the most advanced applications of RNAi therapeutics in the clinic, and it continues to do so. We are excited to be working with Dicerna to be able to advance a needed therapeutic for the treatment of PH1,” said Dr. Mark J. Murray, Tekmira’s President and CEO.

“As a core pillar of our business strategy, we continue to engage in partnerships where our technology improves the risk profile and accelerates the development programs of our collaborators and provides meaningful non-dilutive financing to TKMR,” added Dr. Murray.

“Dicerna is focused on realizing the full clinical potential of our proprietary pipeline of highly targeted RNAi therapies by applying proven technologies,” said Douglas Fambrough, Ph.D., Chief Executive Officer of Dicerna. “By drawing on Tekmira’s extensive and deep experience with lipid nanoparticle delivery to the liver, the agreement will streamline the development path for DCR-PH1. We look forward to initiating Phase 1 trials of DCR-PH1 in 2015, aiming to fill a high unmet medical need for patients with PH1.”

The news release also provides a high level description of the various technologies being researched and brought to market and a bit more information about the liver disorder being addressed by this research,

About RNAi

RNAi therapeutics have the potential to treat a number of human diseases by “silencing” disease-causing genes. The discoverers of RNAi, a gene silencing mechanism used by all cells, were awarded the 2006 Nobel Prize for Physiology or Medicine. RNAi trigger molecules often require delivery technology to be effective as therapeutics.

AboutTekmira’s LNP Technology

Tekmira believes its LNP technology represents the most widely adopted delivery technology for the systemic delivery of RNAi triggers. Tekmira’s LNP platform is being utilized in multiple clinical trials by Tekmira and its partners. Tekmira’s LNP technology (formerly referred to as stable nucleic acid-lipid particles, or SNALP) encapsulates RNAi triggers with high efficiency in uniform lipid nanoparticles that are effective in delivering these therapeutic compounds to disease sites. Tekmira’s LNP formulations are manufactured by a proprietary method which is robust, scalable and highly reproducible, and LNP-based products have been reviewed by multiple regulatory agencies for use in clinical trials. LNP formulations comprise several lipid components that can be adjusted to suit the specific application.

About Primary Hyperoxaluria Type 1 ( PH1)

PH1 is a rare, inherited liver disorder that often results in severe damage to the kidneys. The disease can be fatal unless the patient undergoes a liver-kidney transplant, a major surgical procedure that is often difficult to perform due to the lack of donors and the threat of organ rejection. In the event of a successful transplant, the patient must live the rest of his or her life on immunosuppressant drugs, which have substantial associated risks. Currently, there are no FDA approved treatments for PH1.

PH1 is characterized by a genetic deficiency of the liver enzyme alanine:glyoxalate-aminotransferase (AGT), which is encoded by the AGXT gene. AGT deficiency induces overproduction of oxalate by the liver, resulting in the formation of crystals of calcium oxalate in the kidneys. Oxalate crystal formation often leads to chronic and painful cases of kidney stones and subsequent fibrosis (scarring), which is known as nephrocalcinosis. Many patients progress to end-stage renal disease (ESRD) and require dialysis or transplant. Aside from having to endure frequent dialysis, PH1 patients with ESRD may experience a build-up of oxalate in the bone, skin, heart and retina, with concomitant debilitating complications. While the true prevalence of primary hyperoxaluria is unknown, it is estimated to be one to three cases per one million people.1 Fifty percent of patients with PH1 reach ESRD by their mid-30s.2

About DCR-PH1

Dicerna is developing DCR-PH1, which is in preclinical development, for the treatment of PH1. DCR-PH1 is engineered to address the pathology of PH1 by targeting and destroying the messenger RNA (mRNA) produced by HAO1, a gene implicated in the pathogenesis of PH1. HAO1 encodes glycolate oxidase, a protein involved in producing oxalate. By reducing oxalate production, this approach is designed to prevent the complications of PH1. In preclinical studies, DCR-PH1 has been shown to induce potent and long-term inhibition of HAO1 and to significantly reduce levels of urinary oxalate, while demonstrating long-term efficacy and tolerability in animal models of PH1.

About Dicerna’s Dicer Substrate Technology

Dicerna’s proprietary RNAi molecules are known as Dicer substrates, or DsiRNAs, so called because they are processed by the Dicer enzyme, which is the initiation point for RNAi in the human cell cytoplasm. Dicerna’s discovery approach is believed to maximize RNAi potency because the DsiRNAs are structured to be ideal for processing by Dicer. Dicer processing enables the preferential use of the correct RNA strand of the DsiRNA, which may increase the efficacy of the RNAi mechanism, as well as the potency of the DsiRNA molecules relative to other molecules used to induce RNAi.

You can find more information about Tekmira here and about Dicerna here. I mentioned Tekmira previously in a Sept. 28, 2014 post about Ebola and treatments.

Further south at the University of California at San Diego (UCSD), researcher and founder of Solstice Biologics, Dr Steven Dowdy has developed and patented a new technique for delivering RNAi drugs into cells according to a Nov. 18, 2014 news item on Azonano,

Small pieces of synthetic RNA trigger a RNA interference (RNAi) response that holds great therapeutic potential to treat a number of diseases, especially cancer and pandemic viruses. The problem is delivery — it is extremely difficult to get RNAi drugs inside the cells in which they are needed. To overcome this hurdle, researchers at University of California, San Diego School of Medicine have developed a way to chemically disguise RNAi drugs so that they are able to enter cells. Once inside, cellular machinery converts these disguised drug precursors — called siRNNs — into active RNAi drugs. …

A Nov. 17, 2014 UCSD news release (also on EurekAlert) by Heather Buschman, which originated the news item, describes the issues with delivering RNAi drugs to cells and the new technique,

“Many current approaches use nanoparticles to deliver RNAi drugs into cells,” said Steven F. Dowdy, PhD, professor in the Department of Cellular and Molecular Medicine and the study’s principal investigator. “While nanotechnology protects the RNAi drug, from a molecular perspective nanoparticles are huge, some 5,000 times larger than the RNAi drug itself. Think of delivering a package into your house by having an 18-wheeler truck drive it through your living room wall — that’s nanoparticles carrying standard RNAi drugs. Now think of a package being slipped through the mail slot — that’s siRNNs.”

The beauty of RNAi is that it selectively blocks production of target proteins in a cell, a finding that garnered a Nobel Prize in 2006. While this is a normal process that all cells use, researchers have taken advantage of RNAi to inhibit specific proteins that cause disease when overproduced or mutated, such as in cancer. First, researchers generate RNAi drugs with a sequence that corresponds to the gene blueprint for the disease protein and then delivers them into cells. Once inside the cell, the RNAi drug is loaded into an enzyme that specifically slices the messenger RNA encoding the target protein in half. This way, no protein is produced.

As cancer and viral genes mutate, RNAi drugs can be easily evolved to target them. This allows RNAi therapy to keep pace with the genetics of the disease — something that no other type of therapy can do. Unfortunately, due to their size and negatively charged chemical groups (phosphates) on their backbone, RNAi drugs are repelled by the cellular membrane and cannot be delivered into cells without a special delivery agent.

It took Dowdy and his team, including Bryan Meade, PhD, Khirud Gogoi, PhD, and Alexander S. Hamil, eight years to find a way to mask RNAi’s negative phosphates in such a way that gets them into cells, but is still capable of inducing an RNAi response once inside.

In the end, the team added a chemical tag called a phosphotriester group. The phosphotriester neutralizes and protects the RNA backbone — converting the ribonucleic acid (RNA) to ribonucleic neutral (RNN), and thus giving the name siRNN. The neutral (uncharged) nature of siRNNs allows them to pass into the cell much more efficiently. Once inside the cell, enzymes cleave off the neutral phosphotriester group to expose a charged RNAi drug that shuts down production of the target disease protein. siRNNs represent a transformational next-generation RNAi drug.

“siRNNs are precursor drugs, or prodrugs, with no activity. It’s like having a tool still in the box, it won’t work until you take it out,” Dowdy said. “Only when the packaging — the phosphotriester groups — is removed inside the cells do you have an active tool or RNAi drug.”

The findings held up in a mouse model, too. There, Dowdy’s team found that siRNNs were significantly more effective at blocking target protein production than typical RNAi drugs — demonstrating that once siRNNs get inside a cell they can do a better job.

“There remains a lot of work ahead to get this into the clinics. But, in theory, the therapeutic potential of siRNNs is endless,” Dowdy said. “Particularly for cancer, viral infections and genetic diseases.”

The siRNN technology forms the basis for Solstice Biologics, a biotech company in La Jolla, Calif. that is now taking the technique to the next level. Dowdy is a co-founder of Solstice Biologics and serves as a Board Director.

Here’s a link to and a citation for the research paper,

Efficient delivery of RNAi prodrugs containing reversible charge-neutralizing phosphotriester backbone modifications by Bryan R Meade, Khirud Gogoi, Alexander S Hamil, Caroline Palm-Apergi, Arjen van den Berg, Jonathan C Hagopian, Aaron D Springer, Akiko Eguchi, Apollo D Kacsinta, Connor F Dowdy, Asaf Presente, Peter Lönn, Manuel Kaulich, Naohisa Yoshioka, Edwige Gros, Xian-Shu Cui, & Steven F Dowdy. Nature Biotechnology (2014) doi:10.1038/nbt.3078 Published online 17 November 2014

This paper is behind a paywall.

I have not been able to locate a website for Solstice Biologics but did find a rather curious item about Dr. Dowdy and a shooting incident last year. From a Sept. 18, 2013 news article by Kat Robinson for thewire.sheknows.com,

A wealthy San Diego community is shaken after a man opens fire on his former neighborhood early Wednesday morning. Police say Hans Petersen, a 48-year-old man, is the prime suspect in the shooting of Steven Dowdy and Michael Fletcher.

There’s also a Nov. 8, 2013 article about the incident by Lucas Laursen for Nature magazine,

On September 18 [2013], former Traversa Therapeutics CEO Hans Petersen went on a shooting spree. One of two people wounded was molecular biologist Steven Dowdy, a professor at University of California San Diego (UCSD) School of Medicine, in La Jolla, and cofounder of Traversa, according to a San Diego police report.…

The rest of the article is behind a paywall.