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Smyth JS, Truong JK, Rao A, Lin R, Foulke-Abel J, Adorini L, Donowitz M, Dawson PA, Keely SJ. Farnesoid X receptor enhances epithelial ACE2 expression and inhibits virally induced IL-6 secretion: implications for intestinal symptoms of SARS-CoV-2. Am J Physiol Gastrointest Liver Physiol 2023; 325:G446-G452. [PMID: 37697930 PMCID: PMC10887846 DOI: 10.1152/ajpgi.00099.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/01/2023] [Accepted: 09/01/2023] [Indexed: 09/13/2023]
Abstract
Intestinal inflammation and diarrhea are often associated with SARS-CoV-2 infection. The angiotensin converting enzyme 2 (ACE2) receptor plays a key role in SARS-CoV-2 pathogenesis, facilitating entry of the virus into epithelial cells, while also regulating mucosal inflammatory responses. Here, we investigated roles for the nuclear bile acid receptor farnesoid X receptor (FXR) in regulating ACE2 expression and virally mediated inflammatory responses in intestinal epithelia. Human colonic or ileal enteroids and cultured T84 and Caco-2 monolayers were treated with the FXR agonists, obeticholic acid (OCA) or GW4064, or infected with live SARS-CoV-2 (2019-nCoV/USA_WA1/2020). Changes in mRNA, protein, or secreted cytokines were measured by qPCR, Western blotting, and ELISA. Treatment of undifferentiated colonic or ileal enteroids with OCA increased ACE2 mRNA by 2.1 ± 0.4-fold (n = 3; P = 0.08) and 2.3 ± 0.2-fold (n = 3; P < 0.05), respectively. In contrast, ACE2 expression in differentiated enteroids was not significantly altered. FXR activation in cultured epithelial monolayers also upregulated ACE2 mRNA, accompanied by increases in ACE2 expression and secretion. Further experiments revealed FXR activation to inhibit IL-6 release from both Caco-2 cells infected with SARS-CoV-2 and T84 cells treated with the viral mimic, polyinosinic:polycytidylic acid, by 46 ± 12% (n = 3, P < 0.05) and 35 ± 6% (n = 8; P < 0.01), respectively. By virtue of its ability to modulate epithelial ACE2 expression and inhibit virus-mediated proinflammatory cytokine release, FXR represents a promising target for the development of new approaches to prevent intestinal manifestations of SARS-CoV-2.NEW & NOTEWORTHY Activation of the nuclear bile acid receptor, farnesoid X receptor (FXR), specifically upregulates ACE2 expression in undifferentiated colonic epithelial cells and inhibits virus-induced proinflammatory cytokine release. By virtue of these actions FXR represents a promising target for the development of new approaches to prevent intestinal manifestations of SARS-CoV-2 infection.
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Affiliation(s)
- Jessica S Smyth
- School of Pharmacy and Biomolecular Sciences, The Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Jennifer K Truong
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, Georgia, United States
| | - Anuradha Rao
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, Georgia, United States
| | - Ruxian Lin
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, Georgia, United States
| | - Jennifer Foulke-Abel
- Gastroenterology Division, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Luciano Adorini
- Intercept Pharmaceuticals, San Diego, California, United States
| | - Mark Donowitz
- Gastroenterology Division, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Paul A Dawson
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, Georgia, United States
| | - Stephen J Keely
- School of Pharmacy and Biomolecular Sciences, The Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
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