Differential Gene Expression Profiles Involved in the Inflammations Due to COVID-19 and Inflammatory Bowel Diseases and  the Investigation of Predictive Biomarkers.

Gastrointestinal manifestations in COVID-19 were attributed to 74-86% of the hospitalised patients due to severe or prolonged pathogenesis. Though it is a respiratory disease, the impact it elicits on the gastrointestinal tract and brain are intense. Inflammatory bowel disease including Crohn's disease and ulcerative colitis are idiopathic inflammatory disorders of the gastrointestinal tract. The intrinsic mechanisms involved in gut inflammations due to a respiratory viral disease can be deciphered when the gene expression profiles of COVID-19 and IBD are compared. The current study utilises an integrated bioinformatics approach to unravel them. The publicly available gene expression profiles of colon transcriptomes infected with COVID-19, Crohn's disease and Ulcerative colitis were retrieved, integrated and analysed for the identification of differentially expressed genes. The inter-relational analysis along with gene annotation and pathway enrichment detailed the functional and metabolic pathways of the genes during normal and diseased conditions. The protein-protein interactions deduced from the STRING database and the identified hub genes predicted potential biomarker candidates for COVID-19, Crohn's disease and ulcerative colitis. The inflammatory response pathways were upregulated and enrichment of chemokine signalling, altered lipid metabolism, coagulation and complement cascades were seen in all three conditions along with impaired transport mechanisms. CXCL11, MMP10, and CFB are predicted to be overexpressed biomarkers, whilst GUCA2A, SLC13A2, CEACAM, and IGSF9 as downregulated novel biomarker candidates for colon inflammations. The three miRNAs hsa-miR-16-5p, hsa-miR-21-5p, and hsa-miR-27b-5p exhibited significant interactions with the upregulated hub genes and four long non-coding RNAs NEAT1, KCNQ1OT1, and LINC00852 capable of regulating miRNA were also predicted. This study offers significant information on the underlying molecular mechanisms of inflammatory bowel disease with identification of potential biomarkers.