Open Access

ARTICLE

Smad8 is involvement in follicular development via the regulation of granulosa cell growth and steroidogenesis in mice

by DAOLUN YU¹, DEYONG SHE², KAI GE¹, LEI YANG¹, RUINA ZHAN¹, SHAN LU^3,*, YAFEI CAI^4,*

1 College of Biotechnology and Pharmaceutical Engineering, West Anhui University, Lu’an, 237012, China
2 Lu’an Academy of Agricultural Sciences, Lu’an, 237001, China
3 College of Life Sciences, Anhui Normal University, Wuhu, 241000, China
4 College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China

* Corresponding Authors: SHAN LU. Email: ; YAFEI CAI. Email:

(This article belongs to the Special Issue: Cellular Signal Transduction in Biological Activities)

BIOCELL 2024, 48(1), 139-147. https://doi.org/10.32604/biocell.2023.045884

Received 11 September 2023; Accepted 23 November 2023; Issue published 30 January 2024

Abstract

Background: SMAD family proteins (SMADs) are crucial transcription factors downstream of transforming growth factor beta (TGF-ß)/SMAD signaling pathways that have been reported to play a pivotal role in mammalian reproduction. However, the role of SMAD family member 8 (SMAD8, also known as SMAD9), a member of the SMAD family, in mammalian reproduction remains unclear. Methods: We employed RNA interference techniques to knock down Smad8 expression in mouse granulosa cells (GCs) to investigate the effects of Smad8 on GC growth and steroidogenesis. Results: Our findings revealed a significant decrease in the proliferative capacity and a substantial increase in the apoptosis rate of GCs after transfection with Smad8-siRNA for 48 h. Subsequent hormone assays demonstrated a significant decrease in estradiol (E₂) levels, whereas progesterone (P₄) remained unchanged. Further mechanistic analysis showed that the mRNA expression of proliferating cell nuclear antigen (Pcna), Cyclin D2, cell cycle-dependent kinase 4 (Cdk4), B-cell lymphoma-2 (Bcl-2), estrogen receptor (Er), luteinizing hormone receptor (Lhr) and cytochrome P450 family 19 subfamily A member 1 (Cyp19a1) significantly decreased. Conversely, the mRNA of cysteine aspartate proteinase 3 (Caspase 3) significantly increased, wheras Bcl2-associated X (Bax), follicle-stimulating hormone receptor (Fshr) and cytochrome P450 family 11 subfamily A member 1 (Cyp11a1) remained unchanged compared to the controls. Conclusion: This study indicates that Smad8 knockdown inhibits cell proliferation, promotes apoptosis, reduces Er and Lhr transcription, and decreases E₂ production in mouse GCs. These findings suggest that Smad8 may serve as a novel genetic marker for mammalian reproduction.

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