This episode was filmed on July 17th, 2020.
For more information on the COVID-19 pandemic, check out our playlist linked in the description.
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At this point, it’s safe to say we’re trying a little bit of everything
to fight the virus that causes COVID-19.
Everything from traditional vaccines and drugs approved for other diseases,
to newer, less proven strategies, to some totally out there stuff that’s never been done before.
In particular, some researchers are interested in arming our bodies
with some brand new virus-killing tech.
Here are a couple things they’re trying, and how they might work.
One high-tech therapy, being developed by researchers at the
University of California San Diego, basically tricks the virus, and lures it into a trap.
These so-called cellular nanosponges are tiny decoys that imitate human cells.
Rather than the squishy material that goes into kitchen sponges,
the nanosponges are made up of a synthetic core
wrapped in an envelope of lipid molecules derived from cell membranes.
And just like real human cells, the nanosponges have surface receptors,
which act as docking stations for signals and other stuff outside the cell to get in.
The virus that causes COVID-19, called SARS-CoV-2, uses the spikes that stick
out of its surface to hijack specific receptors on host cells, like a key unlocking a door.
That allows the virus to get inside the cell, start replicating, and infect other cells.
So the idea is that the viruses will bump into the nanosponges
and get their protein keys stuck in the decoy receptor locks.
That ties them up and leaves them unable to reach their actual cells, so they can’t do any harm.
Since the nanosponges are made from cell membranes,
you can change the type of cell they’re mimicking to customize the results.
The researchers have developed two varieties so far,
in order to counter the two major ways the virus does its worst damage.
One kind has an outer membrane derived from human lung cells to target infection in lung tissue.
Scientists think that the COVID-19 virus infects lung cells directly,
leading to respiratory failure in the worst cases.
The other has a membrane made from macrophages.
These are a type of large white blood cell that plays an important role in fighting off pathogens.
But scientists think macrophages also play a pivotal role
in setting off an overpowered immune response when the virus infects them,
causing significant harm to patients.
A high enough dose of nanosponges can neutralize the virus
before it wreaks havoc in these two types of cells,
preventing the worst of the illness and enabling recovery.
The researchers tested whether viruses would actually fall for this high-tech trickery.
They mixed different doses of each type of nanosponge with samples
of SARS-CoV-2 virus, and let the little decoys work their magic for one hour.
When they added the virus-nanosponge mixtures to samples of human cells,
the ones that had been mixed with enough nanosponge were unable to infect them.
One of the coolest parts of this is that the nanosponges may work on a variety of viruses,
even if they mutate and change their form slightly.
That’s because those viruses still need surface receptors.
And our cells change way slower than viruses do.
So the decoy strategy should work
as long as the nanosponge membranes have the same surface receptors.
Of course, this will need more testing in animals
before it can even move on to human tests, so it won’t be available all that soon.
But these membrane bubbles may not be the only way lipid molecules can help us.
Enter the impressively named PAC-MAN lipitoids,
which would outfit our cells with their own virus-destroying weaponry.
PAC-MAN stands for Prophylactic Antiviral CRISPR in huMAN cells.
We’re not saying that they reached for that one, but they reached for that one.
This system is based on CRISPR-CAS,
which has become a favorite lab tool for manipulating DNA.
But that’s not how it started. In nature, it’s a way for bacteria and other microbes
to protect themselves from pathogens, like viruses.
When a pathogen invades the cell,
the cell copies a small fragment of the offending genetic material.
If an invader that matches that sequence tries infecting the cell again,
CRISPR recognizes it from the copy, and deploys a set of molecular scissors
to chop the enemy into little pieces.
Scientists have been designing their own CRISPRs to get various organisms’ cells
to do all kinds of things, including to fight off disease.
Researchers at Stanford University were already working on a CRISPR-based system
to fight influenza when COVID-19 hit, so they shifted gears.
And they’ve shown it’s able to target coronavirus RNA, at least in mathematical simulations.
But it needs a delivery system to get into actual living cells in the human body.
So the Stanford group has teamed up with another at Berkeley National Lab that makes one.
That’s the lipitoid part.
These molecules, which resemble the lipids in cell membranes,
form bubbles that are no bigger than a virus, and can deliver DNA into cells.
In our tissues, the lipitoids should be able to attach to the cells’ outer membranes
and deploy PAC-MAN into the cell through a temporary opening.
Once inside, PAC-MAN stands guard and ensures that
any coronavirus genetic material that gets into the cell is chopped up immediately,
preventing an infection from taking hold.
And the researchers say that PAC-MAN lipitoids
are effective against synthetic versions of the COVID-19 virus.
The next step would be to test in animals.
But the researchers think it could take years to go through animal testing
to human clinical trials, and hopefully be deployed in the real world, so we’ll have to stay tuned.
It’s encouraging to know that scientists are harnessing more than
just the usual virus-fighting repertoire.
We really are trying everything, from tiny sponges to viral RNA-destroying bubbles.
We’re hopeful that something will stick.
In the meantime, we’re staying home and staying safe, and we hope you are too.
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