Important Data from South Korea, Can Zinc Help Prevent COVID-19 (Lecture 32)
Welcome to another MedCram covid-19 update. This is for March 6, 2020. Total confirmed cases now over 100,000. Other than mainland China, South Korea has the most confirmed infections because it’s well known that they’re doing aggressive testing.
There’s an article in the Business Insider that goes over that. It says South Korea has tested 140,000 people now. If you think about that, they’ve tested more people inside their country than we have confirmed cases in the world. That could explain why it’s death rate is just 0.6%, far lower than in China or in the United States.
There’s a nice article here from Bloomberg talking about the virus testing Blitz. What’s interesting about this testing in South Korea is that these test kits that they’re using are a little bit different than the ones that we have, and their sensitivity rates are well over 95 percent according to the director of the Korean Society for laboratory medicine.
What does that mean? Again? South Korea has tested more than 140,000 people for the new coronavirus and has confirmed more than 6,000 cases. And that is a fatality rate at around 0.6%. This suggests that, as many health experts have predicted, the virus’s fatality rate seems to decrease as more cases are reported. This just mathematics, right? As the denominator of a fraction increases, the value of that ratio drops.
In the US, by contrast, we’ve only tested about 1,500 people, and there have been 221 confirmed cases and 12 deaths, suggesting a death rate of 5%. Of course, we know that there’s a number of people out there that are positive for coronavirus that we just haven’t picked up. That’s because our testing capacity has been limited, and that’s been reported because our CDC decided to go along with a different test kit, which was flawed in many ways, and that has caused the delay.
The good news though is that a lot of testing is going to be coming online in the next couple of weeks, and we should see the number of cases going up. Yes, but it should show that mathematically that the fatality rate should also drop.
I think right now as of March 6th, the best example that we have how this virus is behaving is South Korea because they’ve done aggressive testing, and they have a relatively modern healthcare delivery system very similar to that here in the United States. I will put the links to these articles in the description below.
So I’ve got a lot of requests out there to talk about the new medication that’s undergoing trials like remdesivir, also vitamin supplements and, for instance, zinc, which we’ll talk about shortly.
To be able to understand how all of these things are affecting how the virus infects or replicates in the body, you’re going to have to have some basic understanding of molecular biology. So bear with me over the next 10 to 15 minutes as we talk about the pathophysiology and the molecular biology of how coronavirus infects human cells.
Now in terms of nomenclature, remember that coronavirus is a family of viruses, and that family of viruses belong to a bigger group of viruses called nidovirales. So you might see that term as well.
I’m going to walk you through now exactly what happens with covid-19 infection by the SARS-COV-2 virus. We’ve got a cell. This side is the inside of the cell, and this is outside, and here we have the nucleus. This is called the cytoplasm.
The nucleus has a double-stranded set of DNA, which is deoxyribonucleic acid. This holds all of the instructions for all of the proteins and structures and things in the cell. This is in fact, the organism’s genome.
Now what occurs next is something called transcription. Transcription is the copying of that DNA code into a single stranded RNA code. Again, that’s known as transcription.
Now that RNA molecule leaves the nucleus and goes into the cytoplasm where it has special modification that is made to it, and this special modification tells the cell that it’s ready to be translated into a protein, and that is something called a five prime cap and a poly A tail. In other words, a lot of A’s at the end.
Now when that occurs, there’s something called ribosomes. There’s a large subunit ribosome and a small subunit ribosome, and that ribosome reads the code as it goes down from the 5 prime end to the 3 prime end.
As it reads the nucleotides three at a time, it comes up with a code that when those three letters are lined up, it means that there’s a specific amino acid that has to be placed on there, and that uses tRNA, etc, etc.
But the byproduct of that is you get a protein coming out of the ribosome. And of course, this protein is not made up of nucleotides. This protein is made up of amino acids. So this is a protein, and this is called translation.
That’s the difference between transcription, which is going from a nucleotide to a nucleotide. Translation is when you go from a nucleotide to amino acids to make a protein, and this is really what everything is made up of is protein.
Proteins have different structures; proteins can be made into enzymes; proteins could be made into all sorts of things in the cell, and that is what the cell does, and the codes for all of these proteins are included in the DNA. So this is really the central dogma of molecular biology.
So now let’s bring in the viron. I’m drawing lines here, but you should be aware that the outside of this cell is something called a lipid bilayer. Actually the nucleus is a double layer of a bilayer, which we don’t have to worry about. but if you were to look at this very carefully, there would be a hydrophilic layer on the bottom and the top, and in the middle it would be lipophilic. So it’s known as a lipid bilayer.
Well, guess what? This virus also is made up of a lipid bilayer, and it has a hydrophilic side on the outside, and it has a lipophilic on the inside. So it looks very similar. This is the reason why you can destroy viruses with detergents. Detergents can break that up.
This virus has proteins. Specifically, we’ll talk about the coronavirus since that’s what we are concerned about. There are proteins that are embedded in this lipid bilayer, and this protein that I’m drawing here right now is called the S protein. It goes all the way through the lipid membrane.
Now, there are other proteins in there. For instance, there are M proteins. There are also E proteins. They all have their specific function, or structure, to keep this virus intact. Then what is inside is the genome. It’s a tightly packed, very large RNA genome, and it’s bound with N proteins. There are N proteins all through here binding the RNA molecule.
So you’ve got S proteins that help bind at the end here; they are going to dock with cells. You have E protein which is a membrane inside of the bilipid membrane layer. You have an M protein, which is a protein also in the membrane. You have N proteins, which help bind it. All of these are proteins that have to be coded by something. Then, of course, you have the RNA. That’s key here is understanding that coronavirus is an RNA virus.
In this situation, we have a receptor on the surface of the human cell. Here, which is known as the ACE2 receptor, or ACE2 protein. This S protein fits perfectly into that ACE2 and binds to it. When one of these comes and binds, what you get at that point look something similar to this. You can see here that all of the viral contents come into the cytoplasm.
let’s redraw this RNA molecule from the virus, and you’ll start to see something very astounding. That’s right. It’s an RNA, and it has a five prime cap; it has a poly A tail, just exactly as we have our messenger RNA ready for translation.
Also notice that the cell incorporates the viral envelope as part of its outer membrane. As a result of that, these S proteins that were there initially now become part of the cellular membrane, marking it potentially for cellular destruction.
Meanwhile, our ribosomes jump right on to this viral genome and start to march down the RNA. This is what’s known as a positive sense RNA. What does that mean? That means that when the ribosomes come onto this RNA, and they start to go from the five prime down to the three prime end, it’s going to make a protein, and the protein that it makes is something called an RNA-dependent RNA polymerase.
So here it starts to make this protein, and there it is. That’s abbreviated RNA-dependent RNA polymerase; otherwise known as a replicase. What this means is that this protein that is coded for by this mRNA will now take this positive-stranded RNA. It’s only one stand. It will now march from the other ends because it reads from the three prime ends.
It will start to march in this direction, going along the RNA and make another RNA that is complementary to the previous one here. This will be the 5 prime end. This will be the three prime end. Of course, this is going to be complementary to the original, so this will be a negative-stranded RNA.
But guess what? This RDRP is then going to come on to this one and start over on this side, and it’s going to read down this way. The product of that is going to be the original viral genome. So you can see here that this RNA replicase is going to be making more and more RNAs so that they can package these into new virulence that this cell is going to be making. So it can make more virus.
Now the part that really blows me away when this RNA-dependent RNA polymerase starts to go back on again, and it starts to do this, sometimes it doesn’t reach right at the end. Sometimes it reaches from here and will only copy this part, and so you’ll get a shorter RNA, or it’ll come from this side here and I’ll get a shorter RNA.
Well, when you get these shorter RNAs, these are known as subgenomic RNAs, or SGRNAs, and some of them are positive and of course; some of them are going to be negative because they’re complementary.
This viral RNA-dependent RNA polymerase will just make more SGRNAs or negative-SGRNAs. Guess what? These smaller ones also code for the smaller proteins on the virus. So all of these RNAs can be seen and read by ribosomes that the host is donating to the cause. See it hijacks your cell, and so these smaller proteins can be, for instance, M proteins which the virus needs to be made for it. It can also be E proteins.
So the virus comes into the cell, and the key here that you have to understand is it gives up its RNA into the cell, and it’s ready-made for the ribosomes of the cell to make this protein right here called RNA-dependent RNA polymerase. Anything that ends in an ACE is an enzyme, and it tells you what it does. It’s an RNA-dependent, which means it reads RNA, and it makes more RNA. That’s what a polymerase is.
It puts a little nucleotides together into a long chain with little beads. That information helps tell the ribosomes instead of making the proteins that your cell needs to make, it makes the protein that the virus wants to make, and it does it in this very clever way.
So the question is, how can we interrupt this? Because what happens after this is some of these ribosomes are floating around in the cytoplasm, but some of these ribosomes are actually attached to a membrane, which is contiguous with this outer membrane. So they can insert all of those proteins just like they want, and then the reverse of what happened here at the beginning occurs where these things butt off, and little viruses get packaged and they go off. That’s how one viron is able to go into one human being, and millions and millions of viruses come out.
It’s because it hijacks the molecular biology of the cells, and it happens to be that these ACE2 receptors are generally speaking in the lower portion of your respiratory tract. With all of these cellular outer membranes, with all of these foreign proteins, the immune system is going to start attacking these cells. That’s what happens with these lower respiratory cells; they become inflamed; they leak fluid. That’s what causes pneumonia and respiratory failure.
Let’s think about this. What would happen if we could somehow inhibit this nasty enzyme called RNA-dependent RNA polymerase? Well, as it turns out there is something that can be done. There was some in vitro; in vitro means in a Petri dish experiment that was done, that showed that the molecule zinc was able to inhibit this RNA-dependent RNA polymerase.
But how did they get the zinc into the cell? They did it through a little pour-on that allowed zinc to come into the cell in higher concentrations than it would normally have done. So how did that work? Let’s take a look at it and see what happened in that situation.
So here’s an article that was published in 2010. Zinc Inhibits Coronavirus and Arterial Virus RNA Polymerase Activity in vitro and Zinc Ionophores Block the Replication of These Viruses in Cell Culture.
So here’s that enzyme we were talking about, RNA polymerase, that nasty enzyme that is coded for by the RNA genome that goes directly into the cell. So let’s look at this abstract. It talks about using something called PT, which is a zinc ionophore that allows zinc to come into the cell in higher concentrations.
They also used the actual virus SARS-COV, which is not covid-19 virus, but in fact the one that was seen in 2002. But it is very closely related to the virus that we’re seeing today and also binds to the same receptor ACE2. It did show that zinc was found to block the initiation step of RNA synthesis. They found for the SARS-cov that RDRP elongation, that’s the RNdR polymerase elongation, was inhibited, and template binding was reduced.
When they went ahead and bound the zinc with EDTA, which is a binding substrate, they notice that this inhibitory effect was reversed. In other words, showing conclusively that it was the zinc that was slowing it down.
Here are the author summary reinforces what we just learned about the coronavirus. They say that positive-stranded RNAs, which is exactly what the coronavirus is, include many important pathogens. They have evolved a variety of replication strategies, but are unified in the fact that an RNA-dependent RNA polymerase, that’s the thing that we showed, functions as the core enzyme of their RNA synthesizing machinery. Nothing else can work unless you have this RDRP working to make more RNA molecules.
They show you that this is a crucial function and their key targets for antiviral research. Increased intracellular Zinc concentrations are known to effectively impaired replication of a number of RNA viruses by interfering with the correct proteolytic processing of viral polyproteins.
Here, we not only show that corona and arterial virus replication can be inhibited by increasing levels, but also demonstrate that this effect may be based on direct inhibition of RDRPs. Here’s a really telling figure here. We have an increasing concentration here on the x-axis, and here we’re looking at RNA 1, which is the product of the RNA-dependent RNA polymerase.
We can see here that when there’s a zero concentration of zinc, the virus can basically do what it wants. But as we start to increase the concentration of zinc, you can see that that quickly diminishes, and the RNA-dependent RNA polymerase can no longer do what it wants to do.
So in summary, what they found was that the combination of zinc ions and then a way to get those zinc ions into the cell with zinc-ionophore PT effectively inhibits nidovirus replication and cell culture. This may be a novel solution for inhibiting the RdRPs of SARS-COV in the future.
Of course, the issue is how do you get the zinc into the cells? This is a really far cry to say that just zinc lozenges is going to protect you from having coronavirus because as we know there are no randomized trials looking at zinc in coronavirus, especially the current one, because there are no randomized trials involved with this coronavirus at all.
So can we say that taking zinc supplements is going to help you with coronavirus? No, we can’t say that. We can’t say what the appropriate doses. We can’t even say that taking oral zinc is going to increase your intracellular concentration of zinc, but we can say that if you’re deficient in zinc, then you’re probably going to be deficient intracellularly.
So it behooves you to make sure that you’re not deficient in zinc. It really opens up more questions that should be answered by more studies. The nice thing about zinc, of course, is that it’s a water-soluble compound, and it’s going to be difficult to overdose on zinc unlike your fat-soluble vitamins like vitamin A, D, etc.
So getting back to the life cycle of the coronavirus. The other thing that is an area of potential attack would be this ACE2 receptor, which we will cover in later updates. Thank you for joining us.