Taurine ameliorates negative energy balance-induced gene expression alterations in buffalo granulosa cells

Negative Energy Balance (NEB), characterized by high serum free fatty acids (FFAs) and low glucose levels, is a common condition during early postpartum in dairy animals. NEB impairs postpartum fertility by negatively impacting the function of granulosa cells, the key cells in regulating ovarian folliculogenesis and estrogen production. Our previous studies identified reduced serum taurine levels, a sulfur-containing beta-amino acid, during the postpartum period in buffaloes, suggesting a potential association between taurine deficiency and postpartum reproductive problems. Therefore, the objective of the present in vitro study was to evaluate whether taurine could ameliorate NEB-induced alterations in lipid accumulation and the expression of genes related to steroidogenesis, gonadotropin signaling and taurine function in primary buffalo granulosa cells. Buffalo granulosa cells were cultured for 48 h for initial establishment, and subsequently exposed to three different NEB conditions (NEB1: 200 µM FFA and 50 mg/dl glucose; NEB2: 400 µM FFA and 40 mg/dl glucose; NEB3: 800 µM FFA and 30 mg/dl glucose) for 24 h. The culture media under each NEB condition were then supplemented with taurine at four different concentrations (50, 100, 150, and 200 µg/ml), and the cells were cultured in taurine-supplemented media for an additional 24 h. Cells in NEB control groups were maintained under corresponding NEB conditions for 48 h. The cells were subjected to Oil-Red-O staining, MTT assay, and gene expression studies. MTT assay showed no significant change in cell viability between NEB conditions and vehicle control (VC) or between taurine-treated and NEB groups. However, lipid accumulation was higher in NEB compared to VC and taurine-treated groups. The NEB conditions downregulated the genes involved in steroidogenesis ( CYP19A1 , STAR , and HSD17B1 ), gonadotropin signaling ( FSHR and LHR ), and taurine biosynthesis (CSAD), transport ( TauT) and response ( TUG1 ), but upregulated the expression of CD36 , a fatty acid translocase. Taurine significantly ( P < 0.05) ameliorated NEB-induced alterations in gene expression, indicating taurine’s potential in mitigating NEB effects on buffalo granulosa cells. Bioinformatics analyses suggested that TUG1, a long non-coding RNA, may contribute to taurine-mediated regulation of gene expression through a putative miRNA sponge mechanism. Overall, 200 µg/ml of taurine showed the most consistent beneficial effect modulating the alterations in gene expression patterns in buffalo granulosa cells across the NEB conditions studied. Hence, in vivo studies are needed in the future to evaluate the potential of taurine as a nutritional supplement to buffaloes during early postpartum.