SARS-Cov-2 spike induces intestinal barrier dysfunction through the interaction between CEACAM5 and Galectin-9.

Background: Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5), as a typical tumor marker, has been found to exert immunomodulatory effects in many diseases. We previously reported the clinical and molecular evidences supporting that SARS-Cov-2 infected the gastrointestinal (GI) tract and found a reduction of CEACAM5 in COVID-19 patients' feces which associated with gut dysbiosis. Yet the role of CEACAM5 in GI infection is ill-defined. Methods: Mice models were established through intraperitoneally injecting with recombinant viral spike-Fc to mimic the intestinal inflammation. We collected duodenum, jejunum, ileum and colon samples after 6h, 2 days, 4 days and 7 days of spike-Fc or control-Fc injection to perform proteomic analysis. Blood was collected from healthy donors and peripheral blood mononuclear cells (PBMC) were separated by density gradient centrifugation, then CD4+ T cells were isolated with magnetic beads and co-cultured with Caco-2 cells. Results: In addition to intestinal CEACAM5, the expression of tight junction and the percent of CD4+ T lymphocytes were significantly decreased in spike-Fc group compared to control (p < 0.05), accompanied with increased level of inflammatory factors. The KEGG analysis revealed differentially expressed proteins were mainly enriched in the coronavirus disease (COVID-19), tight junction, focal adhesion, adherens junction and PI3K-Akt signaling pathway. Protein-protein interaction (PPI) network analysis identified the interaction between CEACAM5 and Galectin-9 that was also verified by molecular docking and co-IP assay. We further confirmed a reduction of CEACAM5 in SARS-CoV-2 spike stimulated enterocytes could promote the expression of Galectin-9 protein in CD4+T cells. Then it gave rise to the increasing release of inflammatory factors and increased apoptosis of CD4+T cells by inhibition of PI3K/AKT/mTOR pathway. Ultimately intestinal barrier dysfunction happened. Conclusion: Our results indicated that CEACAM5 overexpression and Galectin-9 knockdown played a protective role in intestinal barrier injury upon spike-Fc stimulation. Collectively, our findings identified firstly that SARS-CoV-2 spike induced intestinal barrier dysfunction through the interaction between CEACAM5 and Galectin-9. The result provides potential therapeutic targets in intestinal barrier dysfunction for treating severe COVID patients.

Expression of ACE2, TMPRSS2, and SARS-CoV-2 nucleocapsid protein in gastrointestinal tissues from COVID-19 patients and association with gastrointestinal symptoms.

BACKGROUND: Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can infect the gastrointestinal (GI) tract in coronavirus disease 2019 (COVID-19) patients, the mechanism of GI tract injury is largely unknown. We aimed to study the potential factors that cause COVID-19 GI symptoms. METHODS: We investigated the expression and co-localization of angiotensin converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2), SARS-CoV-2 nucleocapsid protein (NP), and the severity of inflammation in GI tissues from COVID-19 patients (n = 19) by immunofluorescence and histopathologic staining, and then studied their associations with GI symptoms. RESULTS: Infected stomach tissues showed significantly higher ACE2 expression than uninfected ones, while infected duodenum tissues showed significantly higher TMPRSS2 expression than uninfected ones. The expression of TMPRSS2 exhibited a moderate correlation with viral NP across different GI tissues, while no significant association was observed between ACE2 and viral NP. Some GI symptoms such as diarrhea and nausea, were related to the expression level of ACE2, TMPRSS2 or the severity of inflammation. Furthermore, age and elevated aspartate transaminase were major risk factors for disease progression. CONCLUSIONS: ACE2 and TMPRSS2 were essential proteins in the SARS-CoV-2 infection of GI tract, while TMPRSS2 rather than ACE2 may play a more important role. GI symptoms may derive from the host receptor expression level and pro-inflammatory response in COVID-19 patients after viral infection of GI tissues, and further exacerbate the disease. So targeting TMPRSS2 and inflammation may represent an effective strategy for treating COVID-19 patients with GI symptoms.

Rectal Indomethacin and Spraying of Duodenal Papilla With Epinephrine Increases Risk of Pancreatitis Following Endoscopic Retrograde Cholangiopancreatography.

BACKGROUND & AIMS: Rectal indomethacin and spraying of the duodenal papilla with epinephrine might reduce the incidence of pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP). We performed a randomized trial to compare the effects of the combination of indomethacin and epinephrine (IE) vs indomethacin plus saline (IS) in prophylaxis of post-ERCP pancreatitis (PEP). METHODS: We performed a double-blind trial at 10 centers in China, from February 2017 to October 2017, of 1158 patients with native papilla undergoing ERCP. The patients were assigned randomly to groups given IE (n = 576) or IS (n = 582). All patients received a single dose of rectal indomethacin within 30 minutes before ERCP; 20 mL of dilute epinephrine (IE group) or saline (IS group) then was sprayed on the duodenal papilla at the end of ERCP. The primary outcome was the incidence of overall PEP. Data were analyzed on an intention-to-treat principle. RESULTS: The study was terminated at the interim analysis for safety concerns and futility. The groups had similar baseline characteristics. PEP developed in 49 patients in the IE group (8.5%) and in 31 patients in the IS group (5.3%) (relative risk, 1.60, 95% CI, 1.03-2.47; P = .033). There were no significant differences between groups in proportions of patients with postsphincterotomy bleeding (2.1% in the IE group and 1.5% in the IS group) and biliary infection (1.2% in the IE group and 2.2% in the IS group). CONCLUSIONS: In a randomized trial, we found the combination of rectal indomethacin with papillary epinephrine spraying increased the risk of PEP compared with indomethacin alone. Spray epinephrine should not be used with rectal indomethacin for prevention of post-ERCP pancreatitis. ClincialTrials.gov no: NCT03057769.