When talking about the pandemic, host cell surface angiotensin converting enzyme might not be a household phrase. But it’s part of an important piece of research completed by the Naval Research Laboratory and the National Center for Advancing Translational Sciences, part of the NIH. The research, just accepted by a peer review scientific journal, has to do with how the virus actually goes about infecting people. For more, Federal Drive with Tom Temin spoke with research chemist, and acting head of the optical nanomaterials section at the Naval Research Lab, Dr. Mason Wolak.
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Tom Temin: Dr. Wolak Good to have you on.
Dr. Mason Wolak: Thank you so much. It’s a pleasure to be here today.
Tom Temin: First of all, tell us about the collaboration between the NLR and the NCATS. How did that all work?
Dr. Mason Wolak: Well, it got started basically in late March, early April of 2020. The section that I run at NRL has a great deal of experience using quantum dots and nanoparticles for biological applications. And we thought that we can make an impact in studying the current pandemic. So we contacted NIH through a colleague of mine from grad school, and he put us in contact with Dr. Kirill Gorshkov at NCATS, and through a series of virtual meetings, we discussed the different technologies that we thought we could bring to bear on the problem and decided that there was synergy, and then just move forward with developing a pretty complicated and interesting probe to study the virus.
Tom Temin: In layman’s terms, tell us what it is you were looking at with respect to the spikes on the outside of this protein — we’ve all seen those pictures on television with it looks like a soccer ball with red spikes sticking out.
Dr. Mason Wolak: Right. This is very helpful to to give kind of a visualization of what the virus looks like. So the virus is spherical in nature, the inside of the virus has its RNA, and that RNA is a genetic code that allows it to replicate itself. So the exterior of the virus is studded with these spike proteins. The spike proteins basically determine how the virus itself interacts with its environment. So it determines how it moves around in the bloodstream, and how it interacts with human cells. So what we wanted to do is to mimic the virus itself, but do so in a non-infectious, non-hazardous way. So because of the SARS-CoV-2 virus is deadly, it can only be studied in specialized biosafety three level laboratories. So this really limits the amount of people and amount of researchers that can look at the virus and study the virus. So what we wanted to do is we wanted to make an alternative, essentially like a mimic of the virus, but that’s not infecting so that it can be used in various laboratories anywhere around the world.
Tom Temin: In other words, a cell with no RNA, so to speak.
Dr. Mason Wolak: Yes. We refer to it as a pseudovirion. So our pseudovirion, instead of having a central sphere that contains the genetic code of the virus, it has a central sphere that is light emitting. And then what we do is we take the actual spike proteins from the virus and essentially graph them onto the exterior of our quantum dot, our central sphere. So now we have a mimic of the virus, it’s relatively the same size, it’s essentially the same shape as the virus. And it has the same proteins that the virus uses to interact with human cells. But now it’s not infectious. So we can actually use it in a variety of different tests to see how the virus interacts with the human cells. So one of the things here is that the central quantum dot actually emits light. Now, this is super important, because the actual virus is so small that you can’t actually see it in an optical microscope. So what we do is we use the pseudovirion with a special microscope called a confocal microscope, which collects light emitted from particles. So our pseudovirion emits light, and so we can actually track its position when we use it to treat human cells.
Tom Temin: So the theory then is that the spikes on the outside are not what are dangerous to human life, but what’s inside the virus’s own sphere — so you substituted that part.
Dr. Mason Wolak: Exactly. So what makes the virus so deadly is that once the virus gets inside of the cell, it can actually replicate itself and make multiple copies of itself and then exit those viral particles outside of the cell. And then they can basically look around for more cells to infect. So what we really want to do is we want to block that interaction and we want to block the virus from being able to get inside of the cell. That’s the main thing that we’re looking at with our research. How do we block that interaction?
Tom Temin: This was a way of seeing it in action in other words.
Dr. Mason Wolak: Yes, exactly. So we’re able to when we treat human cells, this is work that’s all done at NCATS by Dr. Gorshkov — when we treat human cells, they can actually look at the cell in real time and we can differentiate the position of the receptor molecule that’s on the exterior of the human cell from the position of our psuedovirion, which we’re treating the cell with. So essentially, we have a system that you can kind of think of as like a lock in a key. So the lock is the ACE2, the angiotensin converting enzyme that is on the outside of the human cell. The key is the spike protein that’s on the outside of the virus, or in our case on the outside of this quantum dot that emits light. So the key comes in and makes an attachment to the ACE2 receptor. So this is the first step of infection essentially. So once that complex of the virus and the ACE2 is made, that complex is then dragged inside of the cell through a process called endocytosis. So using our technique, we can actually visualize the binding, the endocytosis, or the internalization of the virus into the cell, or the pseudovirion rather into the cell. And then we can track to see where the pseudovirion goes inside of the cell once it’s inside of it.
Tom Temin: It sounds like watching a horror movie in very tiny miniature. What’s it take to be able to construct such a thing, a dot that emits light and then to graft an actual cell’s enzymes on the outside?
Dr. Mason Wolak: This is when things get a little bit complicated, right? This is pretty complicated chemistry. So our section has a great deal of expertise and using these quantum dots, and we’ve been making them for decades essentially. And so we understand the chemistry. So typically, they’re made up of cadmium and selenide. But we’re able to tailor the quantum dot chemistry such that we can specifically make different emission colors. And we can change the size of the quantum dot. And we can change the surface coating of the quantum dot, which allows it to bind to biological molecules. So we purchased the spike proteins from different biological companies that basically…
Tom Temin: Sells these things in very tiny quantities that you can’t see for a lot of money.
Dr. Mason Wolak: Yeah, exactly. And then we perform some chemistry that essentially binds the spike protein to the exterior of our quantum dots.
Tom Temin: So you didn’t really need to have an actual coronavirus protein to do this.
Dr. Mason Wolak: For this specific project, yes, we need the coronavirus spike protein. But I think what you bring up is a very important concept is that this is really kind of a general and modular approach and we’re looking forward to trying to look at it with different viruses and different receptors. So we understand what proteins are important for some other disease, we can actually adapt our system to study those other diseases as well.
Tom Temin: And so understanding or being able to even visualize the penetration mechanism into the human cells of this type of virus, how can that help further the battle against it?
Dr. Mason Wolak: So this is really the nuts and bolts of what we’re trying to do. So what we want to do is we want to block this interaction, we want to block this spike protein ACE2 interaction, we want to keep the virus outside of the cells. So we know from our study that we’ve been able to treat our cells with both pseudovirus and SARS-CoV-2 antibodies at the same time. And what happens is, when we look at the cells over time, the pseudovirion can’t infiltrate the cell when the antibodies around. So essentially what’s happening is the antibodies are latching onto the spike proteins preferentially. So they’re kind of gumming up the key, right, so now that spike protein can no longer fit into the ACE2 lock. So this observation proves that we can use our technology to screen for drugs to see if they can block this key interaction. Right now NCATS is starting to look at high throughput screening. So they have special instrumentation that they can use to simultaneously look at up to 1536 individual drugs in a single experiment. So they also have access to the entire FDA human approved drug library. And so they can treat human cells with both the pseudovirions and our drug targets. And then they can look at the cells and see whether or not the pseudovirion gets inside of the cell. If they find that the cells aren’t infiltrated with a pseudovirion, then they know that the drug actually blocked the pseudovirion. So we can expect that they have the same effect on the real virus. So if or when we get any hits, we can then suggest that drug for immediate clinical trials in humans, and that can give us our faster access to drugs that can be used to treat COVID-19. So the nice thing here is that we’re looking at drugs that are already FDA human approved. So this will in theory allow us to identify drugs that can be repurposed rapidly for treatment of COVID-19. NCATS has access to more than 10,000 different biologically active molecules to test.
Tom Temin: If I’m hearing it correctly sounds like an alternative to the vaccine as a possibility.
Dr. Mason Wolak: So there’s different ways to think about this. Yes, it could either be used as a treatment to treat people who are infected with COVID-19. So to mitigate the extent of the infection that the person is currently going through, so if you can block the virus from continuing to replicate and continuing to invade more and more cells inside of the human, that can help you with your recovery. But also, you could conceivably think of this as a way in which to prevent people from becoming infected. So NRL, for example, Naval Research Lab, we’re interested in this from the standpoint that deployed naval ships are really very unique closed systems, right. So if you think of like a submarine, there’s virtually no way that you can get the crew of the submarine to appropriately socially distance. And so we’ve already seen, like outbreaks on the USS Theodore Roosevelt, where there’s more than 650 crewmen who became infected, and that severely compromises mission shore readiness.
Tom Temin: And we should point out also that the research that you have done with NCATS has been accepted in a peer reviewed journal. Tell us what happened there.
Dr. Mason Wolak: We wrote up the research and we wrote a paper on everything that we’ve accomplished so far, corresponding authors on this were Dr. Karill Gorshkov and Dr. Eunkeu Oh at NRL. Dr. Kimihiro Susumu also contributed to quantum dot synthesis at NRL. I have to take a second and say that this team, it’s been a pleasure working with them. They’re super dedicated scientists, they’re all incredibly talented, and they’ve really worked tirelessly to try to solve this problem. The importance of having the research published is that it gets it in front of the scientific community, other people that are already working on this problem. So the paper itself has generated great interest. So far, it’s been read over 3000 times and there’s been multiple media stories and press releases that have covered what we’ve done so far. And so we’re already starting to field inquiries from biotech companies that are interested in either collaborating or using the technology, or, for example, sending us drug targets that they’re making for testing. Once we share our research with the scientific community that allows other scientists to look at what we’ve done and maybe they can find a different way to apply what we’ve come up with. Or maybe they can find new ideas for ways to block this interaction. So it’s not only through collaboration and interaction with with our team, but also they can use these ideas for their to further their own research. So that’s really what’s needed at this point with a pandemic is we really need all of our talented scientists thinking about this problem. And we’re going to have to science our way out of this is kind of the expression I’ve been using.
Tom Temin: I guess if we’re lucky, we’ll find out aspirin can do the blocking.
Dr. Mason Wolak: That would be fantastic.
Tom Temin: Dr. Mason Wolak is research chemist and acting head of the optical nanomaterials section at the Naval Research Laboratory. Thanks so much.
Dr. Mason Wolak: Thank you so much.