Molecular Endocrinology, Functional Genomics and Systems Biology Laboratory, Animal Biochemistry Division, National Dairy Research Institute, Karnal, 132001, Haryana, India.
Cell Tissue Res. 2021 Dec;386(3):649-660. doi: 10.1007/s00441-021-03524-6. Epub 2021 Oct 2.
Crosstalk between follicular fluid (FF) and granulosa cells (GCs) plays a vital role in the regulation of folliculogenesis, ensuring regular reproductive cycle in mammals. This crosstalk is primarily mediated by hormones and signaling molecules, such as cytokines and chemokines. Recently, extracellular microRNAs (miRNAs) have gained a lot of attention in cell-to-cell communication. Extracellular miRNA transportation occurs through exosomes, a kind of micro-vesicles produced from almost all cells. However, the mode of non-exosomal miRNA internalization is not much studied. In the present study, we explored the role of neuropilin-1 (NRP-1) as a receptor in internalizing FF non-exosomal miRNAs in GCs. We first confirmed the expression of NRP-1 in GCs during follicular development followed by its role in the internalization of miR-210, a non-exosomal miRNA. This study showed that incubation of GCs with a non-exosomal fraction of FF increased the content of miR-210 in GCs as compared to their control. To illustrate the role of NRP-1 as a receptor, NRP-1 was knockdown using siRNA. Silencing experimental results showed a significant decrease in uptake of miR-210 in NRP-1 knockdown GCs. Furthermore, downstream expression analysis of miR-210 target genes (CYP19A1, PCNA, and EFNA3) also confirmed the NRP-1 mediated miR-210 internalization. Results of the present study clearly demonstrated that FF non-exosomal miR-210 can be internalized through the NRP-1 receptor. Furthermore, differential expression of NRP-1 in GCs suggests its role in follicular development. Overall, these findings suggest that FF non-exosomal miRNA plays an important role in GC functions and female reproduction.
卵泡液 (FF) 和颗粒细胞 (GC) 之间的串扰在调节卵泡发生中起着至关重要的作用，确保哺乳动物的生殖周期正常。这种串扰主要由激素和信号分子介导，如细胞因子和趋化因子。最近，细胞外 microRNAs (miRNAs) 在细胞间通讯中引起了广泛关注。细胞外 miRNA 的运输是通过外泌体进行的，外泌体是几乎所有细胞产生的一种微小囊泡。然而，非外泌体 miRNA 内化的模式研究还不多。在本研究中，我们探讨了神经纤毛蛋白-1 (NRP-1) 作为受体在 GC 内化 FF 非外泌体 miRNAs 中的作用。我们首先证实了 NRP-1 在卵泡发育过程中在 GC 中的表达，随后研究了其在 miR-210 内化中的作用，miR-210 是一种非外泌体 miRNA。本研究表明，与对照相比，将 GC 与 FF 的非外泌体部分孵育会增加 GC 中 miR-210 的含量。为了说明 NRP-1 作为受体的作用，我们使用 siRNA 敲低了 NRP-1。沉默实验结果表明，NRP-1 敲低 GC 中 miR-210 的摄取量显著减少。此外，miR-210 靶基因 (CYP19A1、PCNA 和 EFNA3) 的下游表达分析也证实了 NRP-1 介导的 miR-210 内化。本研究结果清楚地表明，FF 非外泌体 miR-210 可以通过 NRP-1 受体内化。此外，GC 中 NRP-1 的差异表达表明其在卵泡发育中的作用。总之，这些发现表明 FF 非外泌体 miRNA 在 GC 功能和女性生殖中发挥着重要作用。
