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Kerala Veterinary and Animal Sciences University, Wayanad

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Subject: Biochemistry × Author: DIVYA P. D × End date: 2023 × Start date: 2023 ×
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    ThesisItemOpen Access
    ANALYSIS OF DIFFERENTIAL EXPRESSION OF microRNA IN LIPOPOLYSACCHARIDE CHALLENGED LYMPHOCYTES OF VECHUR AND CROSSBRED CATTLE
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, KERALA VETERINARY AND ANIMAL SCIENCES UNIVERSITY, 2023-03-23) DIVYA P. D; Dr. Shynu M.
    The present study was carried out to analyse the differences in the expression of miRNAs in response to the in vitro LPS stimulation of PBMC cultures of crossbred and Vechur cattle. The study was performed in adult, apparently healthy, female crossbred and Vechur cattle maintained at University Livestock Farm and Fodder Research and Development Scheme, Mannuthy, and Vechur Conservation Unit, Kerala Veterinary and Animal Sciences University, respectively. The known/ novel miRNAs and the differential expression of miRNAs in response to bacterial endotoxin, LPS in PBMCs of the two genetic groups were identified by Short-read Illumina Next Generation Sequencing. Validation of NGS data of selected differentially expressed miRNAs was carried out by qRT-PCR assay. Prediction of target genes of differentially expressed miRNAs, functional gene enrichment analysis, analysis of cellular pathways involved and protein-protein interaction (PPI) network evaluation of the predicted target genes were also studied using various online bioinformatics tools. Cytokines associated with the immune related pathways of targets of differentially expressed miRNAs were analysed by ELISA. The differences in cytokine expression were also measured after overexpression of selected miRNA with miRNA mimics in the PBMC cultures of Vechur cattle. A total of 0.47 and 0.64 million clean reads, with an average Phred score of 34.92 and 34.75 corresponding 55.3 and 62.1 per cent of the adapter trimmed reads, respectively, for crossbred and Vechur samples were retrieved by NGS. Analysis of miRNAome identified 979 and 853 known miRNAs, and 393 and 139 novel miRNAs in samples from Vechur and crossbred cattle, respectively. Differential expression studies of NGS data revealed significant variation in the expression of miRNAs in LPS challenged PBMCs cultures of Vechur cows with respect to crossbred cattle. The results of real time validation of the expression of selected miRNAs by qRT-PCR assay were also consistent with the results of NGS. Functional gene enrichment analysis, analysis of pathways associated to the targets of differentially expressed miRNAs also revealed significant enrichment of targets of differentially expressed miRNAs in many immune related GO terms, immune associated cellular pathways as well as major cell signalling pathways. The PPI network analysis also showed active involvement of proteins encoded by these target genes in many of the important immune mechanisms. The study could identify differences in the immune related pathways associated to target genes of both up regulated and down regulated miRNAs though some pathways were found to be identical among both. Assessment of cytokines associated to the pathways regulated by the target genes of differentially expressed miRNAs in the supernatants from LPS treated PBMC cultures of also showed significant variations in the level of cytokines viz; TNF α, IL-4 and IFN γ among the crossbred and Vechur samples when compared to the control groups within the breed as well as between the breed. A significantly higher level of TNF α was noticed in LPS treated PBMCs of crossbred cattle whereas, IL-4 level was found to be significantly increased in LPS stimulated PBMCs of Vechur cattle compared to the LPS untreated cells from both groups. However, the present study could not detect any significant difference in IFN γ level among the LPS treated and untreated cells of both crossbred and Vechur cattle. The overexpression studies of miRNAs in Vechur PBMCs by transfecting with selected miRNA mimic could identify significant differences in IL-4 level while the changes were negligible with respect to other cytokines. The findings of the current research work suggest that both Vechur and crossbred cattle are having differences in their potential to tackle the immunological changes in response to an acute inflammation caused by the bacterial endotoxin; LPS. These differences might be contributing to the alleged immunological sturdiness to Vechur cattle compared to crossbred animals although, the specifics needs to be further validated.