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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