Age-related integrative transcriptomic profiling of human granulosa cells reveals mRNA-microRNA regulatory network associated with key ovulation dynamics

Advanced maternal age (AMA) patients experience decreased success from assisted reproductive technologies (ART), attributed to the quantity and quality of oocytes, which is significantly influenced by the intrafollicular granulosa cells (GCs). In this study, we compared the mRNA and microRNA (miRNA) transcriptomes between young (< 32 years old) and AMA (> 38 years old) patients' GCs to identify potential ovarian aging-related molecular signatures. We identified 293 and 21 differentially expressed genes (DEGs) and miRNAs (DE miRNAs), respectively, between young and aged GCs. Highly expressed mitochondrial-encoded genes, MT-ND3, MT-ND6, and MT-CYB, were downregulated in aged GCs, indicating potential mitochondrial insufficiency. Additionally, pathway analysis indicates DEGs are involved in inflammation, cytokine signaling, extracellular matrix (ECM) remodeling, and angiogenesis. Key DEGs related to these processes include CXCL8, IL1B, NLRP3, SIGIRR, ANGPT2, ADAM8, and ADAMTS14. Additionally, target gene prediction and pathway analysis of DE miRNAs indicates their potential post-transcriptional regulation of genes associated with cell signaling, mitochondrial function, oxidative stress, apoptosis, and senescence pathways in addition to cytokine signaling, angiogenesis, and ECM remodeling. To investigate regulatory mechanisms further, we looked at the DEGs' convergence with the DE miRNAs predicted target genes and we identified miR-483-3p, miR-1268a, miR-4497, miR-7704, miR-135a-5p, miR-1261, and miR-4791 as potential crucial regulators of genes involved in pathways associated with inflammation, ECM, and angiogenesis. This data suggests that aged GCs have an impaired ability to elicit the same pro-inflammatory response combined with dysregulation of angiogenesis and ECM remodeling compared to young GCs, and miRNA may play a role in regulating key ovulatory processes. While this study identifies potential regulatory relationships between DE miRNAs and DEGs, experimental validation is necessary to confirm the relationships and biological relevance.