SARS-CoV-2 Induces Epithelial-Enteric Neuronal Crosstalk Stimulating VIP Release
Background: Diarrhea is present in up to 30–50% of patients with COVID-19. The mechanism of SARS-CoV-2-induced diarrhea remains unclear. We hypothesized that enterocyte–enteric neuron interactions were important in SARS-CoV-2-induced diarrhea. SARS-CoV-2 induces endoplasmic reticulum (ER) stress in...
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MDPI AG
2023-01-01
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author | Arun Balasubramaniam Philip R. Tedbury Simon M. Mwangi Yunshan Liu Ge Li Didier Merlin Adam D. Gracz Peijian He Stefan G. Sarafianos Shanthi Srinivasan |
author_facet | Arun Balasubramaniam Philip R. Tedbury Simon M. Mwangi Yunshan Liu Ge Li Didier Merlin Adam D. Gracz Peijian He Stefan G. Sarafianos Shanthi Srinivasan |
author_sort | Arun Balasubramaniam |
collection | DOAJ |
description | Background: Diarrhea is present in up to 30–50% of patients with COVID-19. The mechanism of SARS-CoV-2-induced diarrhea remains unclear. We hypothesized that enterocyte–enteric neuron interactions were important in SARS-CoV-2-induced diarrhea. SARS-CoV-2 induces endoplasmic reticulum (ER) stress in enterocytes causing the release of damage associated molecular patterns (DAMPs). The DAMPs then stimulate the release of enteric neurotransmitters that disrupt gut electrolyte homeostasis. Methods: Primary mouse enteric neurons (EN) were exposed to a conditioned medium from ACE2-expressing Caco-2 colonic epithelial cells infected with SARS-CoV-2 or treated with tunicamycin (ER stress inducer). Vasoactive intestinal peptides (VIP) expression and secretion by EN were assessed by RT-PCR and ELISA, respectively. Membrane expression of NHE3 was determined by surface biotinylation. Results: SARS-CoV-2 infection led to increased expression of BiP/GRP78, a marker and key regulator for ER stress in Caco-2 cells. Infected cells secreted the DAMP protein, heat shock protein 70 (HSP70), into the culture media, as revealed by proteomic and Western analyses. The expression of VIP mRNA in EN was up-regulated after treatment with a conditioned medium of SARS-CoV-2-infected Caco-2 cells. CD91, a receptor for HSP70, is abundantly expressed in the cultured mouse EN. Tunicamycin, an inducer of ER stress, also induced the release of HSP70 and Xbp1s, mimicking SARS-CoV-2 infection. Co-treatment of Caco-2 with tunicamycin (apical) and VIP (basolateral) induced a synergistic decrease in membrane expression of Na<sup>+</sup>/H<sup>+</sup> exchanger (NHE3), an important transporter that mediates intestinal Na<sup>+</sup>/fluid absorption. Conclusions: Our findings demonstrate that SARS-CoV-2 enterocyte infection leads to ER stress and the release of DAMPs that up-regulates the expression and release of VIP by EN. VIP in turn inhibits fluid absorption through the downregulation of brush-border membrane expression of NHE3 in enterocytes. These data highlight the role of epithelial-enteric neuronal crosstalk in COVID-19-related diarrhea. |
first_indexed | 2024-03-11T09:05:48Z |
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spelling | doaj.art-40383c3d75514edf99cc8687017e69172023-11-16T19:21:52ZengMDPI AGBiomolecules2218-273X2023-01-0113220710.3390/biom13020207SARS-CoV-2 Induces Epithelial-Enteric Neuronal Crosstalk Stimulating VIP ReleaseArun Balasubramaniam0Philip R. Tedbury1Simon M. Mwangi2Yunshan Liu3Ge Li4Didier Merlin5Adam D. Gracz6Peijian He7Stefan G. Sarafianos8Shanthi Srinivasan9Division of Digestive Diseases, Department of Medicine, Emory University, Atlanta, GA 30322, USADepartment of Pediatrics, Emory University, Atlanta, GA 30322, USADivision of Digestive Diseases, Department of Medicine, Emory University, Atlanta, GA 30322, USADivision of Digestive Diseases, Department of Medicine, Emory University, Atlanta, GA 30322, USADivision of Digestive Diseases, Department of Medicine, Emory University, Atlanta, GA 30322, USAVA Medical Center Atlanta, Decatur, GA 30033, USADivision of Digestive Diseases, Department of Medicine, Emory University, Atlanta, GA 30322, USADivision of Digestive Diseases, Department of Medicine, Emory University, Atlanta, GA 30322, USADepartment of Pediatrics, Emory University, Atlanta, GA 30322, USADivision of Digestive Diseases, Department of Medicine, Emory University, Atlanta, GA 30322, USABackground: Diarrhea is present in up to 30–50% of patients with COVID-19. The mechanism of SARS-CoV-2-induced diarrhea remains unclear. We hypothesized that enterocyte–enteric neuron interactions were important in SARS-CoV-2-induced diarrhea. SARS-CoV-2 induces endoplasmic reticulum (ER) stress in enterocytes causing the release of damage associated molecular patterns (DAMPs). The DAMPs then stimulate the release of enteric neurotransmitters that disrupt gut electrolyte homeostasis. Methods: Primary mouse enteric neurons (EN) were exposed to a conditioned medium from ACE2-expressing Caco-2 colonic epithelial cells infected with SARS-CoV-2 or treated with tunicamycin (ER stress inducer). Vasoactive intestinal peptides (VIP) expression and secretion by EN were assessed by RT-PCR and ELISA, respectively. Membrane expression of NHE3 was determined by surface biotinylation. Results: SARS-CoV-2 infection led to increased expression of BiP/GRP78, a marker and key regulator for ER stress in Caco-2 cells. Infected cells secreted the DAMP protein, heat shock protein 70 (HSP70), into the culture media, as revealed by proteomic and Western analyses. The expression of VIP mRNA in EN was up-regulated after treatment with a conditioned medium of SARS-CoV-2-infected Caco-2 cells. CD91, a receptor for HSP70, is abundantly expressed in the cultured mouse EN. Tunicamycin, an inducer of ER stress, also induced the release of HSP70 and Xbp1s, mimicking SARS-CoV-2 infection. Co-treatment of Caco-2 with tunicamycin (apical) and VIP (basolateral) induced a synergistic decrease in membrane expression of Na<sup>+</sup>/H<sup>+</sup> exchanger (NHE3), an important transporter that mediates intestinal Na<sup>+</sup>/fluid absorption. Conclusions: Our findings demonstrate that SARS-CoV-2 enterocyte infection leads to ER stress and the release of DAMPs that up-regulates the expression and release of VIP by EN. VIP in turn inhibits fluid absorption through the downregulation of brush-border membrane expression of NHE3 in enterocytes. These data highlight the role of epithelial-enteric neuronal crosstalk in COVID-19-related diarrhea.https://www.mdpi.com/2218-273X/13/2/207SARS-CoV-2diarrheaenterocytesenteric neuronsheat shock protein 70 |
spellingShingle | Arun Balasubramaniam Philip R. Tedbury Simon M. Mwangi Yunshan Liu Ge Li Didier Merlin Adam D. Gracz Peijian He Stefan G. Sarafianos Shanthi Srinivasan SARS-CoV-2 Induces Epithelial-Enteric Neuronal Crosstalk Stimulating VIP Release Biomolecules SARS-CoV-2 diarrhea enterocytes enteric neurons heat shock protein 70 |
title | SARS-CoV-2 Induces Epithelial-Enteric Neuronal Crosstalk Stimulating VIP Release |
title_full | SARS-CoV-2 Induces Epithelial-Enteric Neuronal Crosstalk Stimulating VIP Release |
title_fullStr | SARS-CoV-2 Induces Epithelial-Enteric Neuronal Crosstalk Stimulating VIP Release |
title_full_unstemmed | SARS-CoV-2 Induces Epithelial-Enteric Neuronal Crosstalk Stimulating VIP Release |
title_short | SARS-CoV-2 Induces Epithelial-Enteric Neuronal Crosstalk Stimulating VIP Release |
title_sort | sars cov 2 induces epithelial enteric neuronal crosstalk stimulating vip release |
topic | SARS-CoV-2 diarrhea enterocytes enteric neurons heat shock protein 70 |
url | https://www.mdpi.com/2218-273X/13/2/207 |
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