Global gene expression profile of peripheral blood mononuclear cells challenged with Theileria annulata in crossbred and indigenous cattle.

Bovine tropical theileriosis is an important haemoprotozoan disease associated with high rates of morbidity and mortality particularly in exotic and crossbred cattle. It is one of the major constraints of the livestock development programmes in India and Southeast Asia. Indigenous cattle (Bos indicus) are reported to be comparatively less affected than exotic and crossbred cattle. However, genetic basis of resistance to tropical theileriosis in indigenous cattle is not well documented. Recent studies incited an idea that differentially expressed genes in exotic and indigenous cattle play significant role in breed specific resistance to tropical theileriosis. The present study was designed to determine the global gene expression profile in peripheral blood mononuclear cells derived from indigenous (Tharparkar) and cross-bred cattle following in vitro infection of T. annulata (Parbhani strain). Two separate microarray experiments were carried out each for cross-bred and Tharparkar cattle. The cross-bred cattle showed 1082 differentially expressed genes (DEGs). Out of total DEGs, 597 genes were down-regulated and 485 were up-regulated. Their fold change varied from 2283.93 to -4816.02. Tharparkar cattle showed 875 differentially expressed genes including 451 down-regulated and 424 up-regulated. The fold change varied from 94.93 to -19.20. A subset of genes was validated by qRT-PCR and results were correlated well with microarray data indicating that microarray results provided an accurate report of transcript level. Functional annotation study of DEGs confirmed their involvement in various pathways including response to oxidative stress, immune system regulation, cell proliferation, cytoskeletal changes, kinases activity and apoptosis. Gene network analysis of these DEGs plays an important role to understand the interaction among genes. It is therefore, hypothesized that the different susceptibility to tropical theileriosis exhibited by indigenous and crossbred cattle is due to breed-specific differences in the dealing of infected cells with other immune cells, which ultimately influence the immune response responded against T. annulata infection.

The mRNA expression of immune-related genes in crossbred and Tharparkar cattle in response to in vitro infection with Theileria annulata.

Tropical theileriosis is a major protozoan disease of cattle and is associated with high rates of morbidity and mortality. Indigenous cattle (Bos indicus) are less affected by this disease than exotic and crossbred cattle. Genetic basis of resistance to tropical theileriosis in indigenous cattle is not well studied. Recent reports suggest that number of immune response genes expressed differentially in exotic and indigenous breeds play an important role in breed specific resistance to tropical theileriosis. Such studies comparing expression of these genes in crossbred cattle and indigenous cattle are lacking. The present study compares the mRNA expression of immune-related genes in response to Theileria annulata infection in indigenous and crossbred cattle. Peripheral blood mononuclear cells (PBMCs) were isolated from blood samples of indigenous (Tharparkar) and crossbred (HF/BS/Jersey × Hariana) cattle and challenged with prepared ground-up tick supernatant carrying Theileria annulata sporozoites in vitro. qPCR was employed to measure relative mRNA expression of toll-like receptor 10 (TLR10), signal-regulatory protein alpha (SIRPA), MHC class II DQα (BoLA-DQA), musculoaponeurotic fibrosarcoma (MAF) and prion protein (PRNP) genes in infected and control PBMCs from crossbred and indigenous cattle. On the basis of comparative fold change analysis, significant up-regulation in SIRPA, PRNP and MHC DQα genes and significant down-regulation in TLR10, cMAF and MAFB genes in crossbreds as compared to indigenous cattle was observed. Results of the present study suggest that breed specific differential expression of the genes under study may contribute to the breed specific resistance to Theileria annulata infection in indigenous cattle compared to crossbred cattle.