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.

The prognostic roles of hepatitis B virus antibody in diffuse large B-cell lymphoma patients.

Diffuse large B-cell lymphoma (DLBCL) has been correlated with virus infection and immunity status. We retrospectively analyzed the association between HBV antibody and DLBCL development in HBsAg- patients. Compared with HBeAb- patients, HBeAb+ patients displayed unique clinical features. HBV antibody-negative patients had better therapeutic efficiency (p < .05). The media progression-free survival (PFS) and overall survival (OS) of HBV antibody-positive group were shorter than the negative group (p < .05). Furthermore, we found positive association between CD21 and HBsAb and their synergistic effect for prognostic predication. Interestingly, the effect of Rituximab in prognostic improvement was more significant in HBV antibody-positive group than negative group. Univariate analysis showed that HBV antibody was independent risk factor for disease prognosis. Altogether, our investigations identified for the first time the close association between HBV antibody and clinical prognosis in DLBCL patients. These findings provide potential biomarker to predict the effect of Rituximab and prognosis in DLBCL patients.

[EMA-pCR detection of enterohemorrhagic Eschrichia coli O157:H7].

OBJECTIVE: A rapid and effective method with ethidium monoazide bromide (EMA) in combination with PCR (EMA-PCR) was established to detect live Enterohemorrhagic Eschrichia Coli O157:H7. METHODS: The rfbE gene was used as the target gene for PCR detection of Eschrichia Coli O157:H7 by utilizing its pure isolates after the treatment of EMA as the template. The EMA concentration and reaction time was optimized. RESULTS: The use of 10 microg/mL or less EMA did not inhibit the PCR amplification of DNA derived from viable bacteria. The PCR amplification of DNA derived from 2 x 10(7) CFU/mL dead cells can be inhibited by 0.5 microg/mL EMA. The sensitivity of the method was 2 x 10(4) CFU/mL. The results demonstrated that it could detect 1% live bacteria from a mixed bacterial population. CONCLUSION: EMA-PCR can effectively detect live bacteria of O157:H7, it could be a potential rapid detection method applied in public health emergent events.