The present study sought to evaluate mRNA expression profiles in the cultured dermal fibroblasts of Tharparkar (zebu) and Karan-Fries (zebu, Tharparkar × taurine, Holstein Friesian) cattle in response to heat stress. Bioinformatics' analysis identified temperature-regulated biological processes and pathways. Biological processes overrepresented among the earliest genes induced by temperature stress include regulation of stress responses, protein repair, metabolism, protein transport, cell division, and apoptosis. The present microarray platform contains 51,338 synthesized oligonucleotide probes corresponding to at least 36,713 unigenes. A total of 11,183 and 8126 transcripts were differentially expressed with a fold change of ≥ 2 in Tharparkar and Karan-Fries cattle, respectively. Randomly selected real-time validation showed 83.33% correlation with microarray data. Functional annotation and pathway study of the differentially expressed transcripts or genes (DEGs) reveal that upregulated genes significantly (P < 0.05) affect protein processing and NOD-like receptor pathways (NLRs), while downregulated genes were significantly (P < 0.05) found to be associated with cell cycle, metabolism, and protein transport. Gene expression changes include activation of heat shock factors (HSFs), increased expression of heat shock proteins (HSPs), and apoptosis, while decreasing protein synthesis and another metabolism. These findings provide insights into the underlying mechanism of the physiology of heat stress in Tharparkar and Karan-Fries cattle. Understanding the biology and mechanisms of heat stress is critical to developing approaches to ameliorate current production issues for improving animal performance and agriculture economics in tropical climatic conditions. In conclusion, the present study indicates that heat stress differentially affects the expression of the significant number of genes associated with stress response, metabolism, apoptosis, and protein transport in dermal fibroblasts of Tharparkar and Karan-Fries cattle.
Keywords: Apoptosis; Dermal fibroblasts; Heat stress; Metabolism; Stress response; cDNA microarray.