A PTN-Rich MSC Subtype Promotes Cartilage Repair in End-Stage Knee Osteoarthritis

A PTN-rich, CD74-low placenta-derived MSC subtype enhances cartilage repair in end-stage knee osteoarthritis, upregulating SOX9 and suppressing MMP13, IL-6, and IL-1β.

• Why it matters: MSC therapy for end-stage knee osteoarthritis has inconsistent efficacy, and it is unclear whether MSCs can retain cartilage repair capacity in an inflammatory joint environment.
• What they did: Single-cell RNA sequencing of human Kellgren-Lawrence grade (G ) and (G ) KOA joint tissues with exogenous MSCs identified PTN signalling shifts and PTN exhaustion with elevated CD74 in G cartilage; the authors then sorted a PTN-rich CD74-low placenta-derived MSC subtype and tested it in a murine KOA model and patient-derived chondrocyte co-culture.
• The result: The PTN-rich CD74-low subtype improved cartilage repair and reduced inflammatory and catabolic markers, potentially via CD74 suppression and reduced NF-κB signaling, supporting stage-matched, functionally defined cell therapy for end-stage KOA.

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