Gut microbiota-derived metabolites confer protection against SARS-CoV-2 infection [16S rRNA]

The gut microbiome is intricately coupled with immune regulation and metabolism, but its role in Coronavirus Disease 2019 (COVID-19) is not fully understood. Severe and fatal COVID-19 is characterized by poor anti-viral immunity and hypercoagulation, particularly in males. Via 16S sequencing of antibiotic-treated mice, we found that Clostridia species protect mammalian hosts from SARS-CoV-2 intranasal infection, both locally and systemically, via production of short-chain fatty acids (SCFAs). SCFAs reduced viral burdens in the airways and intestines by downregulating the SARS-CoV-2 entry receptor, angiotensin-converting enzyme 2 (ACE2), and enhancing adaptive immunity in male animals. In order to identify other mechanisms by which SCFAs influence the outcome of SARS-CoV-2 infection, we performed RNA-seq on lungs from male GF mice given control or SCFA water for two weeks. We identified a novel role for the gut microbiome in regulating systemic coagulation response by limiting megakaryocyte proliferation and platelet turnover via the Sh2b3-Mpl axis. Taken together, our findings have unraveled novel functions of SCFAs and fiber-fermenting gut bacteria that might be leveraged as pan-coronavirus therapeutics to dampen viral entry and hypercoagulation and promote adaptive anti-viral immunity. Overall design: 8-week-old male C57BL/6 mice were given normal drinking water (n=2) or drinking water containing antibiotics (gentamicin or vancomycin; n=5 each) for two weeks. DNA was extracted from fecal pellets and the V4 region of the 16S rRNA gene was amplified using universal primers and sequenced on an Illumina MiSeq sequencer.