Weighted gene co-expression network analysis reveals key genes and lncRNAs in desi cattle chronically infected with Johne's disease

Johnes disease (JD), caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a chronic enteric disease with significant economic impacts on the dairy industry. To elucidate molecular mechanisms underlying MAP infection in desi cattle (Bos indicus), we conducted a comprehensive transcriptomic study. This revealed 1,905 protein-coding and 3,123 lncRNA genes as differentially expressed in MAP-infected samples, alongside the first comprehensive annotation of 45,947 lncRNAs in desi cattle. Weighted Gene Co-expression Network Analysis identified 11 co-expressed gene modules, with the turquoise module comprising 870 protein- coding genes and 934 lncRNAs, highly correlated with clinical traits. Functional enrichment analysis of this key module revealed significant involvement in defense response, inflammatory processes, and NK cell-mediated immunity and cytotoxicity. GSE analysis revealed suppressed pathways, including NK cell immunity and lectin response, facilitating bacterial persistence in chronic infection, while activated pathways included G-protein-coupled receptor signaling and metabolic pathways. Network approach identified 12 hub genes (IL7R, TLR4, KLRK1, IFNG, TGFB1, CD68, CXCR6, GZMB, KLRG1, MMP9, GZMA, SELL) associated with immune suppression, inflammation, and tissue remodeling. Additionally, 22 lncRNAs co-expressed with hub genes suggesting roles in modulating immune regulation. By identifying critical genes and lncRNAs, our study offers potential targets for developing innovative diagnostic and therapeutic strategies for JD.