Effects of RAC1 on Proliferation of Hen Ovarian Prehierarchical Follicle Granulosa Cells

Abstract

RAC1 belongs to the small G protein Rho subfamily and is implicated in regulating gene expression, cell proliferation and differentiation in mammals and humans; nevertheless, the function of RAC1 in growth and development of hen ovarian follicles is still unclear. This study sought to understand the biological effects of RAC1 on granulosa cell (GC) proliferation and differentiation of hen ovarian prehierarchical follicles. Firstly, our results showed expression levels of RAC1 mRNA in the follicles with diameters of 7.0–8.0 mm, 6.0–6.9 mm and 1.0–3.9 mm were greater than other follicles (p < 0.05). The RAC1 protein was mainly expressed in oocyte and its around GCs and stromal tissues of the prehierarchical follicles by immunohistochemistry. Further investigation revealed the RAC1 gene remarkably enhanced the mRNA and protein expression levels of FSHR (a marker of follicle selection), CCND2 (a marker of cell-cycle progression and GC differentiation), PCNA (a marker of GC proliferation), StAR and CYP11A1 (markers of GC differentiation and steroidogenesis) (p < 0.05). Furthermore, our data demonstrated siRNA interference of RAC1 significantly reduced GC proliferation (p < 0.05), while RAC1 gene overexpression enhanced GC proliferation in vitro (p < 0.05). Collectively, this study provided new evidence that the biological effects of RAC1 on GC proliferation, differentiation and steroidogenesis of chicken ovary follicles.

Novel insights into the regulation of LATS2 kinase in prehierarchical follicle development via the Hippo pathway in hen ovary

“…Based on our present study and previously published reports in other species, LATS2 may play an essential role in controlling the selection of dominant prehierarchical follicles into a differentiation stage of follicular hierarchy and enhancing GC proliferation and steroidogenesis during ovarian development. On the contrary, our data indicated that the GC proliferation index was significantly magnified, in which the expression of genes serving as biomarkers of follicle selection, granulosa cell differentiation, and steroidogenesis ( Xu et al, 2018b ; Tyasi et al, 2020 ), including FSHR, StAR, CYP11A1, ESR1 , and ESR2 (their functions and biological roles were clarified as aforementioned, respectively), were notably elevated by knockdown of LAST2. The LATS2 knockdown result supports the hypothesis that LATS2 plays a suppressive role in ovarian follicle development, and it may hinder GC proliferation, differentiation, steroidogenesis, and follicle selection.…”

Grade follicles transcriptional profiling analysis in different laying stages in chicken

“…Follicular development is a complex physiological process, regulated by diverse genes and endocrine hormones [ 3 ]. Previous studies revealed the effect of GPR12 [ 20 ], GREM1 [ 31 ], BMP4 [ 32 ], RAC1 [ 33 ], FOXO3 [ 34 ], bFGF [ 35 , 36 ], Melatonin [ 37 , 38 ], CSAL1 and CSAL3 [ 39 ] on follicular development. RNA-seq has empowered many research areas and has led to new discoveries throughout the mRNA field [ 40 ].…”

MERTK-Mediated LC3-Associated Phagocytosis (LAP) of Apoptotic Substrates in Blood-Separated Tissues: Retina, Testis, Ovarian Follicles

“…CD36 is highly expressed in GC [137], and CD36 null mice display ovarian morphology resembling those seen in polycystic ovarian syndrome (PCOS), in which there is an abnormally increased number of primary follicles which remain preovulatory [138]. Furthermore, the variations of FAK phosphorylation and RAC1-GTPase driven actin re-arrangement depending on various stages of seminiferous epithelium and ovarian cycles have been detected as well [139][140][141][142]. Further studies are needed to identify the member of phagocytosis machinery providing the cleaning of apoptotic substrates in testes and ovaries.…”