Insulin regulates gap junction intercellular communication in porcine granulosa cells through modulation of connexin43 protein expression.

Gap junction intercellular communication (GJIC) among granulosa cells plays an important role in folliculogenesis, and it is temporal-spatially regulated during follicular development. Connexin (Cx) proteins predominantly form the basal structure of gap junctions in granulosa cells. In our study, immunohistochemical analysis revealed that Cx43 is the most widely expressed connexin in porcine follicles, especially among the large antral follicles.

Epidermal growth factor receptor signaling uncouples germ cells from the somatic follicular compartment at ovulation.

Germ cells are physically coupled to somatic support cells of the gonad during differentiation, but this coupling must be disrupted when they are mature, freeing them to participate in fertilization. In mammalian females, coupling occurs via specialized filopodia that project from the ovarian follicular granulosa cells to the oocyte. Here, we show that signaling through the epidermal growth factor receptor (EGFR) in the granulosa, which becomes activated at ovulation, uncouples the germ and somatic cells by triggering a massive and temporally synchronized retraction of the filopodia.

Localization and expression of CTRP6 in ovary and its regulation by FSH in porcine granulosa cells.

C1q/tumor necrosis factor-related protein 6 (CTRP6) is a newly identified adiponectin paralog with modulating effects on metabolism and inflammation. CTRP6 transcript is detected in human ovarian tissue. However, the expression pattern and function of CTRP6 on ovary have been rarely studied.

BAMBI promotes porcine granulosa cell steroidogenesis involving TGF-β signaling.

Transforming growth factor β (TGF-β), acting as the auto/para endocrine factors, has multi-function in mammalian follicle development. Bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) is considered as a pseudoreceptor in the TGF-β signal pathway which has the similar extracellular structure of TGF-β receptor but lack of intracellular serine/threonine kinase domains. However, the biological function of BAMBI involved in porcine granulosa cell steroidogenesis remains unknown.

Bmal1 interference impairs hormone synthesis and promotes apoptosis in porcine granulosa cells.

In mammals, granulosa cell proliferation, differentiation, luteinization, apoptosis, and hormone synthesis are tightly related to oocyte maturation, follicular development and ovarian function. In current study, we investigated the role of the key circadian clock gene, brain and muscle arnt-like protein-1 (Bmal1), on porcine granulosa cell hormone secretion and apoptosis. The transcription levels of circadian clock genes, including Bmal1 and period circadian clock 2 (Per2), were detected by RT-qPCR.

MAT2B promotes adipogenesis by modulating SAMe levels and activating AKT/ERK pathway during porcine intramuscular preadipocyte differentiation.

Intramuscular fat (IMF) has been demonstrated as one of the crucial factors of livestock meat quality. The MAT2B protein with MAT2α catalyzes the formation of methyl donor S- adenosylmethionine (SAMe) to mediate cell metabolism including proliferation and apoptosis. However, the regulatory effect of MAT2B on IMF deposition is still unclear.