RESUMO
During spermatogenesis, a group of undifferentiated spermatogonia undergoes an essential transition to a differentiating stage, which involves gain of Kit receptor. In the current study, we showed that a small non-coding RNA, miRNA-26b could induce transition from Kit- to Kit+ and inhibit proliferation of spermatogonia. A key transcriptional factor for undifferentiated spermatogonia, Plzf, was proven as a direct target of miR-26b. When undifferentiated spermatogonia were treated with Retinoic acid (RA), miR-26b was increased, further promoting RA-induced differentiation of spermatogonia. In addition, miR-26b could repress 5-hydroxymethylcytosine (5hmC) via repression of Tet3 in spermatogonia. These findings demonstrate that miR-26b might play a role in promoting the transition from Kit- to Kit+ SSCs.
Assuntos
MicroRNAs/fisiologia , Espermatogênese , Espermatogônias/metabolismo , 5-Metilcitosina/análogos & derivados , 5-Metilcitosina/metabolismo , Animais , Apoptose , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células , Células Cultivadas , Proteínas de Ligação a DNA/metabolismo , Dioxigenases , Masculino , Camundongos , MicroRNAs/metabolismo , Proteína com Dedos de Zinco da Leucemia Promielocítica/genética , Proteína com Dedos de Zinco da Leucemia Promielocítica/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-kit/análise , Espermatogônias/citologia , Espermatogônias/efeitos dos fármacos , Tretinoína/farmacologiaRESUMO
Granulosa cells (GCs) are essential somatic cells in the ovary and play an important role in folliculogenesis. Brain-derived neurotropic factor (BDNF) and the TGF-ß pathway have been identified as a critical hormone and signalling pathway, respectively, in GCs. In this study, we found that a conserved microRNA family that includes miR-10a and miR-10b repressed proliferation and induced apoptosis in human, mouse, and rat GCs (hGCs, mGCs and rGCs, respectively). Moreover, essential hormones and growth factors in the follicle, such as FSH, FGF9 and some ligands in the TGF-ß pathway (TGFß1, Activin A, BMP4 and BMP15), inhibited miR-10a and miR-10b expression in GCs. In contrast, the miR-10 family suppressed many key genes in the TGF-ß pathway, suggesting a negative feedback loop between the miR-10 family and the TGF-ß pathway in GCs. By using bioinformatics approaches, RNA-seq, qPCR, FISH, immunofluorescence, Western blot and luciferase reporter assays, BDNF was identified as a direct target of the miR-10 family in GCs. Additionally, reintroduction of BDNF rescued the effects of miR-10a and miR-10b in GCs. Collectively, miR-10a and miR-10b repressed GC development during folliculogenesis by repressing BDNF and the TGF-ß pathway. These effects by the miR-10 family on GCs are conserved among different species.