Distinct Transcriptional Responses to 17β-Estradiol in Human Meniscal Fibrochondrocytes from a Female and a Male Donor

Osteoarthritis (OA) affects women more often than men, and estrogen has been implicated in joint homeostasis, yet its effects on meniscal fibrochondrocytes (MFCs) remain poorly defined. We reanalyzed a public RNA sequencing dataset (Gene Expression Omnibus, GSE199087) of MFCs from two age-matched donors, one female and one male (both 47 years old). Cells from each donor were treated in triplicate with pulsed 17β-estradiol (E2, 240 µM for 1 h every 24 h over 72 h) or vehicle control. Differential expression was assessed with limma-voom, and pathways were identified with Gene Set Enrichment Analysis (GSEA), Enrichr, and iLINCS, retaining only Gene Ontology terms supported by all three. In the female donor’s cells, E2 upregulated DNA replication and cell-cycle pathways and lowered MMP1, MMP2, IL12A, and MYD88. In the male donor’s cells, E2 upregulated chromatin remodeling and developmental signaling pathways, with NOTCH1 among the leading-edge genes, and downregulated antigen presentation pathways and mitochondrial genes. At the gene level, some changes were shared by both donors, including lower TIMP1. Because each sex was represented by one donor, these differences cannot be attributed to sex with confidence. The findings are hypothesis-generating and identify candidate pathways for validation in larger, sex-balanced cohorts.