Tag Archives: neuraminidase

Nano-decoy for human influenza A virus

While the implications for this research are exciting, keep in mind that so far they’ve been testing immune-compromised mice. An Oct. 24, 2016 news item on Nanowerk announces the research,

To infect its victims, influenza A heads for the lungs, where it latches onto sialic acid on the surface of cells. So researchers created the perfect decoy: A carefully constructed spherical nanoparticle coated in sialic acid lures the influenza A virus to its doom. When misted into the lungs, the nanoparticle traps influenza A, holding it until the virus self-destructs.

An Oct. 24, 2015 Rensselaer Polytechnic Institute press release by Mary L. Martialay, which originated the news item, describes the research (Note: Links have been removed),

In a study on immune-compromised mice, the treatment reduced influenza A mortality from 100 percent to 25 percent over 14 days. The novel approach, which is radically different from existing influenza A vaccines, and treatments based on neuraminidase inhibitors, could be extended to a host of viruses that use a similar approach to infecting humans, such as Zika, HIV, and malaria. …

“Instead of blocking the virus, we mimicked its target – it’s a completely novel approach,” said Robert Linhardt, a glycoprotein expert and Rensselaer Polytechnic Institute professor who led the research. “It is effective with influenza and we have reason to believe it will function with many other viruses. This could be a therapeutic in cases where vaccine is not an option, such as exposure to an unanticipated strain, or with immune-compromised patients.”

The project is a collaboration between researchers within the Center for Biotechnology and Interdisciplinary Studies (CBIS) at Rensselaer and several institutions in South Korea including Kyungpook National University. Lead author Seok-Joon Kwon, a CBIS research scientist, coordinated the project across borders, enabling the South Korean institutions to test a drug designed and characterized at Rensselaer. …

To access the interior of a cell and replicate itself, influenza A must first bind to the cell surface, and then cut itself free. It binds with the protein hemagglutinin, and severs that tie with the enzyme neuraminidase. Influenza A produces numerous variations each of hemagglutinin and neuraminidase, all of which are antigens within the pathogen that provoke an immune system response. Strains of influenza A are characterized according to the variation of hemagglutinin and neuraminidase they carry, thus the origin of the familiar H1N1 or H3N2 designations.

Medications to counter the virus do exist, but all are vulnerable to the continual antigenic evolution of the virus. A yearly vaccine is effective only if it matches the strain of virus that infects the body. And the virus has shown an ability to develop resistance to a class of therapeutics based on neuraminidase inhibitors, which bind to and block neuraminidase.

The new solution targets an aspect of infection that does not change: all hemagglutinin varieties of influenza A must bind to human sialic acid. To trap the virus, the team designed a dendrimer, a spherical nanoparticle with treelike branches emanating from its core. On the outermost branches, they attached molecules, or “ligands,” of sialic acid.

The research found that the size of the dendrimer and the spacing between the ligands is integral to the function of the nanoparticle. Hemagglutinin occurs in clusters of three, or “trimers,” on the surface of the virus, and researchers found that a spacing of 3 nanometers between ligands resulted in the strongest binding to the trimers. Once bound to the densely packed dendrimer, viral neuraminidase is unable to sever the link. The coat of the virus contains millions of trimers, but the research revealed that only a few links provokes the virus to discharge its genetic cargo and ultimately self-destruct.

A different approach, using a less structured nanoparticle, had been previously tested in unrelated research, but the nanoparticle selected proved both toxic, and could be inactivated by neuraminidase. The new approach is far more promising.

“The major accomplishment was in designing an architecture that is optimized to bind so tightly to the hemagglutinin, the neuraminidase can’t squeeze in and free the virus,” said Linhardt. “It’s trapped.”

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

Nanostructured glycan architecture is important in the inhibition of influenza A virus infection by Seok-Joon Kwon, Dong Hee Na, Jong Hwan Kwak, Marc Douaisi, Fuming Zhang, Eun Ji Park, Jong-Hwan Park, Hana Youn, Chang-Seon Song, Ravi S. Kane, Jonathan S. Dordick, Kyung Bok Lee, & Robert J. Linhardt. Nature Nanotechnology (2016)  doi:10.1038/nnano.2016.181 Published online 24 October 2016

This paper is behind a paywall.

Simon Fraser University’s (Vancouver, Canada) Feb. 19, 2013 Café Scientifique

There are two very different descriptions of this upcoming event, first from Simon Fraser University’s Café Scientifique webpage description,

Tuesday, February 19
Café Scientifique

Time: 7-8:30pm

Place: CBC, 700 Hamilton St.

Cost: Free, email cafesci@sfu.ca to reserve your spot

The Chemistry behind how Bird’s Nest soup led to Influenza drugs Influenza type A viral infection continues to be a serious health problem facing the human population as it continually changes how it is seen by the immune system by making modifications to the proteins that cover its surface. Dr. Andrew Bennet of SFU’s Chemistry Dept. will discuss how inhibition of one of the viral surface proteins that is called neuraminidase (the N in H5N1) is proving to be a suitable approach in the design of anti-viral drugs. Moderated by Stephen Quinn, CBC Radio. [Canadian Broadcasting Corporation] Everyone welcome, refreshments served. Please email cafesci@sfu.ca to reserve your free seat. 7:00 – 8:30 pm, CBC, 700 Hamilton St. Vancouver

Then there’s this from SFU’s Café Scientifique 2012 – 2013 List of Speakers webpage,

Tuesday, February 19, 2013

The Chemistry Behind How Bird’s Nest Soup Led to Influenza Drugs

Speaker:  Dr. Andy Bennett, Department of Chemistry, SFU

Influenza type A viral infection continues to be a serious health problem facing the human population worldwide as it continually changes how it is seen by the immune system by making modifications to the proteins that cover its surface.  Inhibition of one of the viral surface proteins that is called neuraminidase (the N in H5N1) has proved to be a suitable approach in the design of anti-viral drugs.

Note the location is the CBC Studio at 700 Hamilton Street, Vancouver

Please RSVP to cafe_sci@sfu.ca

Frankly, this seems like less fun that a talk at the Railway Club, which is where one of the other Cafe Scientifique groups usually meets. The Railway Club has a casual informal atmosphere; you can get a beer and some very interesting science conversation and, yes, someone does speak but the whole dynamic changes when you’ve got that beer in hand.  This SFU/CBC setup reminds me too much of sitting in lecture halls.