Mechano-Hypoxia Programs a Coordinated Chondrogenic–Osteochondral Transcriptome in Co-Cultures of Human Nasal Chondrocytes and Bone Marrow–Derived Mesenchymal Stromal Cells

Co-culture also produced significantly higher equilibrium and peak compressive moduli than donor-matched NC monocultures. RT-qPCR showed increased ACAN and SOX9 expression in co-culture, but also increased COL10A1, indicating that hypertrophic features were not fully suppressed. Endpoint RNA sequencing separated co-culture from NC monoculture and identified overlapping proliferation-, extracellular matrix-, and differentiation-associated programs.

Co-culture upregulated proteoglycan- and cartilage-associated genes together with mineralization-, angiogenesis-, and remodeling-associated genes including SPP1, IBSP, DMP1, ALPL, and VEGFA. Mechanotransduction-associated genes and immediate-early transcriptional regulators were also enriched under the applied loading regimen. These findings show that NC-BMSC co-culture under hypoxic dynamic compression enhances cartilage-like matrix formation and mechanical function, but the improved tissue phenotype remains coupled to an osteochondral remodeling transcriptome.

Future optimization should focus on uncoupling matrix induction from hypertrophic and mineralization-associated maturation.