A new tool for studying COVID's impact on gut health
Intestine Chip enables effective in vitro study of coronavirus infections
of the human gut and testing of potential treatments

Date:
November 8, 2021
Source:
Wyss Institute for Biologically Inspired Engineering at Harvard
Summary:
New research using an Intestine Chip has recreated viral infection
of the human gut in vitro using a coronavirus called NL63, which
causes the common cold and is also associated with GI symptoms.



FULL STORY ==========================================================================
Most of us are familiar with COVID-19's hallmark symptoms of a loss of
taste or smell and difficulty breathing, but a full 60% of patients
infected with SARS- CoV-2 also report gastrointestinal symptoms (GI)
such as nausea, diarrhea, and stomach pain. Infection of the gut, which expresses high levels of the ACE2 receptor protein that SARS-CoV-2
uses to enter cells, is correlated with more severe cases of COVID-19,
but the exact interactions between the virus and intestinal tissue
is difficult to study in human patients. Animal models, while useful,
do not fully reflect how human organs react to infection by pathogens,
further limiting our current understanding of how coronaviruses like
SARS-CoV- 2 affect the gut.


==========================================================================
To solve that problem, a team of scientists at the Wyss Institute for Biologically Inspired Engineering at Harvard University and several
other Wyss partner organizations in Boston used a human Intestine Chip previously developed at the Institute to study coronavirus infection and potential treatments in an environment that mimics the human intestine
more effectively than cells grown in a dish.

They infected the Intestine Chip with a coronavirus called NL63 that
causes the common cold and, like SARS-CoV-2, uses the ACE2 receptor to
enter cells, and then tested the effects of various drugs that have been proposed for treating SARS-CoV-2 infection. They found that a drug called nafamostat reduced infection while the drug remdesivir, which has been
used to treat COVID-19 patients, did not reduce infection and actually
damaged the intestinal tissue.

This new preclinical model, which could be used to identify drugs that
can target GI symptoms associated with both the common cold and SARS-CoV-2 virus infections in the future, is described in Frontiers in Pharmacology.

Toxic treatment Most in vitrostudies of coronavirus infection are
performed in organoids (blobs of human organ cells grown in a dish),
which lack many of the features of living tissues in human organs. Organ
Chips address this issue by providing a physiological environment that recreates the tissue-tissue contact and other physical conditions that
organ cells experience in the human body. The Intestine Chip is a device
about the size of a USB memory stick made of a clear, flexible polymer
through which run two parallel channels: one lined with human blood
vessel cells, the other with human intestinal lining cells. A permeable membrane between the two channels ensures that the cells can exchange
molecular messengers, and that substances can be delivered into the blood viathe gut, mimicking digestion. The tissues in the Intestine Chip are continuously stretched and released to recreate the rhythmic movements
caused by muscle contractions in the GI tract.

In addition to ACE2, another membrane protein called TMPRSS2 is also
known to be involved in coronavirus infection. The researchers measured
how much mRNA coding for each protein were produced by the cells in the Intestine Chip, and found that both were much higher than in cultured
human intestine organoids.

They also analyzed individual cells' repertoires of RNA molecules and
confirmed that the Intestine Chip contained a variety of cell types
found in the human gut, including stem cells, goblet-like cells, and
intestinal absorptive cells.



==========================================================================
The team then introduced the coronavirus NL63 into the channel lined
with intestinal cells and observed what happened. The Intestine Chip did
indeed show signs of infection: the layer of gut cells became "leaky"
as the connections between them were compromised by the virus. To try
to cure the infection, the researchers then administered nafamostat, a short-acting anticoagulant drug, into the channel lined with blood vessel
cells to mimic a human being injected with the drug. Nafamostat is a known inhibitor of proteases, a class of proteins that includes TMPRSS2. True
to form, nafamostat administration significantly reduced the amount of
virus present in the Intestine Chip 24 hours after infection, though it
did not restore the integrity of the connections between the cells.

Then the team tried the same experiment using remdesivir, an antiviral
drug that received Emergency Use Authorization from the US Food and Drug Administration for use in treating COVID-19. To their surprise, they found
that remdesivir didn't reduce the amount of virus in the Intestine Chip,
and it also damaged the cells in the blood vessel channel, causing them
to detach almost completely from the channel wall.

"We were surprised that remdesivir displayed such clear toxicity to the vascular tissue in the Intestine Chip. GI symptoms have been previously reported in clinical trials of remdesivir, and this model now gives us a
window into the underlying causes of those symptoms. It could also help
us better understand the efficacy and toxicity of other similar drugs,"
said co-first author Girija Goyal, Ph.D., who is a Senior Research
Scientist at the Wyss Institute.

A more complete picture of human gut health Having established that
their Intestine Chip could successfully model interactions between
viruses, drugs, and the gut, the team tested a variety of other drugs
that are taken orally including toremifene, nelfinavir, clofazimine,
and fenofibrate, all of which have been shown to inhibit infection by SARS-CoV-2 and other viruses in vitro. Of those, only toremifene showed
similar efficacy to nafamostat in reducing NL63 viral load.



========================================================================== Because the immune system interacts with both pathogens and drugs viathe inflammatory response, the researchers then introduced a mixture of human immune cells called ??peripheral blood mononuclear cells (PBMCs) into the
blood vessel channel of the Intestine Chip to study this process. They
found that more PBMCs attached themselves to the blood vessel wall in
chips that had been infected with NL63 than in uninfected chips, and
that the blood vessel cells were damaged. They also observed that NL63 infection caused the secretion of multiple inflammatory cytokines that
signal the body to recruit immune cells to the infection site.

Pre-treating the Intestine Chip with nafamostat prior to the introduction
of the virus and PBMCs did reduce the secretion of some cytokines, but
it did not mitigate the blood vessel damage, nor did it suppress the inflammatory response completely. Nafamostat pre-treatment did, however, increase the production of an antimicrobial protein called Lipocalin-2, implying that this type of protein could play a role in the cellular
response to coronavirus infections.

"This study demonstrates that we can explore complex interactions between cells, pathogens, and drugs in the human intestine using our Intestine
Chip as a preclinical model. We hope it proves useful in the ongoing
effort to better understand the effects of SARS-CoV-2 and to identify
drugs that could be used to combat future viral pandemics," said senior
author and Wyss Founding Director Don Ingber, M.D., Ph.D., who is also
the Judah Folkman Professor of Vascular Biology at Harvard Medical School
and Boston Children's Hospital, and Professor of Bioengineering at the
Harvard John A. Paulson School of Engineering and Applied Sciences.

Co-first authors of the paper are former Wyss members Amir Bein (currently
at Quris Technologies) and Wuji Cao (currently at ETH Zu"rich), and
current Wyss member Seongmin Kim. Additional authors include Arash
Naziripour, Sanjay Sharma, Ben Swenor, Nina LoGrande, Atiq Nurani, Pranav Prabhala, Min Sun Kim, Rachelle Prantil-Baun (currently at Intergalactic Therapeutics), Melissa Rodas, Amanda Jiang, Lucy O'Sullivan, and Gladness
Tilya from the Wyss Institute; Cicely Fadel from the Wyss Institute
and Beth Israel Deaconess Medical Center; Vincent Miao, Andrew Navia,
Carly Ziegler, and Alex Shalek from Harvard University and MIT; and Jose' Ordovas Montan~es from Harvard University, MIT, and Boston Children's
Hospital.

This research was supported by the Defense Advanced Research Projects
Agency (DARPA) under Cooperative Agreement HR0011-20-2-0-040, the
National Institutes of Health (UH3-HL141797), Bill and Melinda Gates Foundation, and Wyss Institute for Biologically Inspired Engineering at
Harvard University.

========================================================================== Story Source: Materials provided
by Wyss_Institute_for_Biologically_Inspired_Engineering_at
Harvard. Original written by Lindsay Brownell. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Amir Bein, Seongmin Kim, Girija Goyal, Wuji Cao, Cicely Fadel, Arash
Naziripour, Sanjay Sharma, Ben Swenor, Nina LoGrande, Atiq
Nurani, Vincent N. Miao, Andrew W. Navia, Carly G. K. Ziegler,
Jose' Ordovas Montan~es, Pranav Prabhala, Min Sun Kim, Rachelle
Prantil-Baun, Melissa Rodas, Amanda Jiang, Lucy O'Sullivan, Gladness
Tillya, Alex K. Shalek, Donald E. Ingber. Enteric Coronavirus
Infection and Treatment Modeled With an Immunocompetent Human
Intestine-On-A-Chip. Frontiers in Pharmacology, 2021; 12 DOI:
10.3389/fphar.2021.718484 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211108130905.htm

--- up 9 weeks, 4 days, 9 hours, 25 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)