Investigation of Metabolome Underlying the Biological Mechanisms of Acute Heat Stressed Granulosa Cells

Abstract

Heat stress affects granulosa cells and the ovarian follicular microenvironment, ultimately resulting in poor oocyte developmental competence. This study aims to investigate the metabo-lomics response of bovine granulosa cells (bGCs) to in vitro acute heat stress of 43 °C. Heat stress triggers oxidative stress-mediated apoptosis in cultured bGCs. Heat-stressed bGCs exhibited a time-dependent recovery of proliferation potential by 48 h. A total of 119 metabolites were identified through LC–MS/MS-based metabolomics of the spent culture media, out of which, 37 metabolites were determined as differentially involved in metabolic pathways related to bioenergetics support mechanisms and the physical adaptations of bGCs. Multiple analyses of metabolome data identified choline, citric acid, 3-hydroxy-3-methylglutaric acid, glutamine, and glycocyamine as being upregulated, while galactosamine, AICAR, ciliatine, 16-hydroxyhexadecanoic acid, lysine, succinic acid, uridine, xanthine, and uraconic acid were the important downregulated metabolites in acute heat stress. These differential metabolites were implicated in various important metabolic pathways directed towards bioenergetics support mechanisms including glycerophospholipid metabolism, the citrate cycle (TCA cycle), glyoxylate and dicarboxylate metabolism, and serine, threonine, and tyrosine metabolism. Our study presents important metabolites and metabolic pathways involved in the adaptation of bGCs to acute heat stress in vitro.

Transcriptomics Reveals Granulosa Cell’s Coping through Redox, Inflammatory, Metabolic and Cytoskeleton Mechanisms under Acute Heat Stress

“…While along with ACAT2, only two other upregulated DEGs are TLR2 and SLC2A4, in CC and MF of GO terms enrichment. Earlier studies involving acute heat stress in bovine skeletal muscles [39] and GCs [72] have reported altered metabolism and insulin signaling, lack of anabolic activities, and extensive reshuffling in the bioenergetics mechanisms involving multiple signaling pathways. Heat stress and associated oxidative stress is shown to lead to upregulated inflammatory response [73,74], while inflammation is energy intensive and leads to metabolic imbalance [75,76].…”

Joint Transcriptome and Metabolome Analysis Prevails the Biological Mechanisms Underlying the Pro-Survival Fight in In Vitro Heat-Stressed Granulosa Cells

“…The cell collection, culture, and treatment methods followed our previous study [ 21 , 22 , 23 ]. In brief, follicular fluid was collected from small follicles (3–8 mm) of cyclic bovine ovaries followed by filtration and centrifugal washings.…”

“…Our previous transcriptome level studies involving an extensive range of temperatures gave useful biological insights into the cellular mechanisms, metabolic level changes, and apoptotic and antioxidant pathways [ 4 , 21 ]. In our LC–MS-based untargeted metabolomics study, important metabolites, metabolic pathways, and their interplay in cellular mechanisms were reported in acute heat-stressed bovine granulosa cells [ 22 ]. Our transcriptome study reported evidence of an intricate fight between pro-survival and pro-death pathways, while the metabolome study suggested differential metabolites directed towards bioenergetic support mechanisms in acute heat-stressed bovine granulosa cells [ 21 , 22 ].…”

“…In our LC–MS-based untargeted metabolomics study, important metabolites, metabolic pathways, and their interplay in cellular mechanisms were reported in acute heat-stressed bovine granulosa cells [ 22 ]. Our transcriptome study reported evidence of an intricate fight between pro-survival and pro-death pathways, while the metabolome study suggested differential metabolites directed towards bioenergetic support mechanisms in acute heat-stressed bovine granulosa cells [ 21 , 22 ]. Integrated transcriptome and metabolome analyses involving correlation and network analyses are efficient strategies to explore the mechanisms underlying a biological system.…”

“…Integrated transcriptome and metabolome analyses involving correlation and network analyses are efficient strategies to explore the mechanisms underlying a biological system. Therefore, this study evaluates cellular physical responses and integrates the transcriptome and metabolome data from acute heat-stressed bovine granulosa cells [ 21 , 22 ] to narrow down and explore new biological insights regarding important genes, metabolites, and adaptive pathways involved in the aftermath of acute heat stress to bovine granulosa cells.…”