Tag Archives: Ronnie H. Fang

Alleviating joint damage and inflammation from arthritis with neutrophil nanosponges

Assuming you’d be happy with limiting the damage for rheumatoid arthritis, at some point in the future, this research looks promisin. Right now it appears the researchers aren’t anywhere close to a clinical trial. From a Sept. 3, 2018 news item on ScienceDaily,

Engineers at the University of California San Diego [UCSD] have developed neutrophil “nanosponges” that can safely absorb and neutralize a variety of proteins that play a role in the progression of rheumatoid arthritis. Injections of these nanosponges effectively treated severe rheumatoid arthritis in two mouse models. Administering the nanosponges early on also prevented the disease from developing.

A Sept. 3, 2018 UCSD press release (also on EurekAlert), which originated the news item, provides more detail,

“Nanosponges are a new paradigm of treatment to block pathological molecules from triggering disease in the body,” said senior author Liangfang Zhang, a nanoengineering professor at the UC San Diego Jacobs School of Engineering. “Rather than creating treatments to block a few specific types of pathological molecules, we are developing a platform that can block a broad spectrum of them, and this way we can treat and prevent disease more effectively and efficiently.”

This work is one of the latest examples of therapeutic nanosponges developed by Zhang’s lab. Zhang, who is affiliated with the Institute of Engineering in Medicine and Moores Cancer Center at UC San Diego, and his team previously developed red blood cell nanosponges to combat and prevent MRSA infections and macrophage nanosponges to treat and manage sepsis.

neutrophil nanosponge cartoon
Illustration of a neutrophil cell membrane-coated nanoparticle.

The new nanosponges are nanoparticles of biodegradable polymer coated with the cell membranes of neutrophils, a type of white blood cell.

Neutrophils are among the immune system’s first responders against invading pathogens. They are also known to play a role in the development of rheumatoid arthritis, a chronic autoimmune disease that causes painful inflammation in the joints and can ultimately lead to damage of cartilage and bone tissue.

When rheumatoid arthritis develops, cells in the joints produce inflammatory proteins called cytokines. Release of cytokines signals neutrophils to enter the joints. Once there, cytokines bind to receptors on the neutrophil surfaces, activating them to release more cytokines, which in turn draws more neutrophils to the joints and so on.

The nanosponges essentially nip this inflammatory cascade in the bud. By acting as tiny neutrophil decoys, they intercept cytokines and stop them from signaling even more neutrophils to the joints, reducing inflammation and joint damage.

These nanosponges offer a promising alternative to current treatments for rheumatoid arthritis. Some monoclonal antibody drugs, for example, have helped patients manage symptoms of the disease, but they work by neutralizing only specific types of cytokines. This is not sufficient to treat the disease, said Zhang, because there are so many different types of cytokines and pathological molecules involved.

“Neutralizing just one or two types might not be as effective. So our approach is to take neutrophil cell membranes, which naturally have receptors to bind all these different types of cytokines, and use them to manage an entire population of inflammatory molecules,” said Zhang.

“This strategy removes the need to identify specific cytokines or inflammatory signals in the process. Using entire neutrophil cell membranes, we’re cutting off all these inflammatory signals at once,” said first author Qiangzhe Zhang, a Ph.D. student in Professor Liangfang Zhang’s research group at UC San Diego.

To make the neutrophil nanosponges, the researchers first developed a method to separate neutrophils from whole blood. They then processed the cells in a solution that causes them to swell and burst, leaving the membranes behind. The membranes were then broken up into much smaller pieces. Mixing them with ball-shaped nanoparticles made of biodegradable polymer fused the neutrophil cell membranes onto the nanoparticle surfaces.

“One of the major challenges of this work was streamlining this entire process, from isolating neutrophils from blood to removing the membranes, and making this process repeatable. We spent a lot of time figuring this out and eventually created a consistent neutrophil nanosponge production line,” said Qiangzhe Zhang.

In mouse models of severe rheumatoid arthritis, injecting nanosponges in inflamed joints led to reduced swelling and protected cartilage from further damage. The nanosponges performed just as well as treatments in which mice were administered a high dose of monoclonal antibodies.

The nanosponges also worked as a preventive treatment when administered prior to inducing the disease in another group of mice.

Professor Liangfang Zhang cautions that the nanosponge treatment does not eliminate the disease. “We are basically able to manage the disease. It’s not completely gone. But swelling is greatly reduced and cartilage damage is minimized,” he said.

The team hopes to one day see their work in clinical trials.

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

Neutrophil membrane-coated nanoparticles inhibit synovial inflammation and alleviate joint damage in inflammatory arthritis by Qiangzhe Zhang, Diana Dehaini, Yue Zhang, Julia Zhou, Xiangyu Chen, Lifen Zhang, Ronnie H. Fang, Weiwei Gao, & Liangfang Zhang. Nature Nanotechnology (2018) DOI: https://doi.org/10.1038/s41565-018-0254-4 Published 03 September 2018

This paper is behind a paywall.

Sponging up the toxins in your blood

It doesn’t sound like these nanosponges are going to help you with your hangover but should you have a snakebite, an E. coli infection or other such pore-forming toxin in your blood, engineers at the University of California at San Diego are working on a solution. From the University of California at San Diego Apr. 14, 2103 news release,

Engineers at the University of California, San Diego have invented a “nanosponge” capable of safely removing a broad class of dangerous toxins from the bloodstream – including toxins produced by MRSA, E. coli, poisonous snakes and bees. These nanosponges, which thus far have been studied in mice, can neutralize “pore-forming toxins,” which destroy cells by poking holes in their cell membranes. Unlike other anti-toxin platforms that need to be custom synthesized for individual toxin type, the nanosponges can absorb different pore-forming toxins regardless of their molecular structures. In a study against alpha-haemolysin toxin from MRSA, pre-innoculation with nanosponges enabled 89 percent of mice to survive lethal doses. Administering nanosponges after the lethal dose led to 44 percent survival.

They’ve produced a video about their work,

I like the fact that this therapy isn’t specific but can be used for different toxins (from the news release),

“This is a new way to remove toxins from the bloodstream,” said Liangfang Zhang, a nanoengineering professor at the UC San Diego Jacobs School of Engineering and the senior author on the study. “Instead of creating specific treatments for individual toxins, we are developing a platform that can neutralize toxins caused by a wide range of pathogens, including MRSA and other antibiotic resistant bacteria,” said Zhang. The work could also lead to non-species-specific therapies for venomous snake bites and bee stings, which would make it more likely that health care providers or at-risk individuals will have life-saving treatments available when they need them most.

Here’s how the nanosponges work (from the news release),

In order to evade the immune system and remain in circulation in the bloodstream, the nanosponges are wrapped in red blood cell membranes. This red blood cell cloaking technology was developed in Liangfang Zhang’s lab at UC San Diego. The researchers previously demonstrated that nanoparticles disguised as red blood cells could be used to deliver cancer-fighting drugs directly to a tumor. …

Red blood cells are one of the primary targets of pore-forming toxins. When a group of toxins all puncture the same cell, forming a pore, uncontrolled ions rush in and the cell dies.

The nanosponges look like red blood cells, and therefore serve as red blood cell decoys that collect the toxins. The nanosponges absorb damaging toxins and divert them away from their cellular targets. The nanosponges had a half-life of 40 hours in the researchers’ experiments in mice. Eventually the liver safely metabolized both the nanosponges and the sequestered toxins, with the liver incurring no discernible damage. [emphasis mine]

It’s reassuring to see that this therapy doesn’t damage as it heals.

For those interested, here’s some technical information about how the nanosponges are created in the laboratory (from the news release),

Each nanosponge has a diameter of approximately 85 nanometers and is made of a biocompatible polymer core wrapped in segments of red blood cells membranes.

Zhang’s team separates the red blood cells from a small sample of blood using a centrifuge and then puts the cells into a solution that causes them to swell and burst, releasing hemoglobin and leaving RBC [red blood cell] skins behind. The skins are then mixed with the ball-shaped nanoparticles until they are coated with a red blood cell membrane.

Just one red blood cell membrane can make thousands of nanosponges, which are 3,000 times smaller than a red blood cell. With a single dose, this army of nanosponges floods the bloodstream, outnumbering red blood cells and intercepting toxins. Based on test-tube experiments, the number of toxins each nanosponge could absorb depended on the toxin. For example, approximately 85 alpha-haemolysin toxin produced by MRSA, 30 stretpolysin-O toxins and 850 melittin monomoers, which are part of bee venom.

In mice, administering nanosponges and alpha-haemolysin toxin simultaneously at a toxin-to-nanosponge ratio of 70:1 neutralized the toxins and caused no discernible damage.

This seems like promising work and, hopefully, they will be testing these nanosponges in human clinical trials soon.

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

A biomimetic nanosponge that absorbs pore-forming toxins by Che-Ming J. Hu, Ronnie H. Fang, Jonathan Copp, Brian T. Luk,& Liangfang Zhang. Nature Nanotechnology (2013) doi:10.1038/nnano.2013.54 Published online 14 April 2013

This paper is behind a paywall. (H/T to EurekAlert [Apr. 14, 2013 news release].)

The last time I wrote about nanosponges it was in the context of oil spills in my Apr. 17, 2012 posting.