Long non-coding RNAs link DNA methylation to immune regulatory networks in bovine subclinical mastitis

Long non-coding RNAs (lncRNAs) are emerging as important regulators of inflammatory and immune signaling, yet their contribution to bovine subclinical mastitis remains poorly defined. Here, we characterized the lncRNA expression landscape associated with disease in milk somatic cells of healthy and subclinical mastitic Vrindavani cattle. We identified 11,403 high-confidence lncRNAs, of which 104 were differentially expressed in subclinical mastitis (adjusted P < 0.05; |log2FC| ≥ 1), with the vast majority upregulated in mastitic samples. Predicted cis- and trans-associated target analyses identified 637 non-redundant genes, and KEGG analysis identified 8 significantly enriched cis-associated pathways and 152 significantly enriched trans-associated pathways (adjusted P < 0.05), predominantly enriched for immune and inflammation-related pathways. These findings prioritized a subset of mastitis-associated lncRNAs for subsequent methylation and interaction-network analyses. A subset of these lncRNAs further overlapped differentially methylated regions (DMRs), suggesting a potential association between lncRNA expression changes and DNA methylation alterations. Integration of lncRNA-miRNA and miRNA-mRNA interactions identified lncRNA-miRNA-mRNA interaction networks involving DMR-associated lncRNAs. Among the prioritized candidates, MSTRG.28878.1 showed overlap with a hypomethylated promoter-associated DMR, increased expression, and multiple connections within the predicted interaction network. Together, these findings identify candidate lncRNAs, methylation-associated loci, and predicted molecular interactions associated with bovine subclinical mastitis and provide a resource for future functional investigation of candidate non-coding RNA-associated mechanisms in disease.