Single-cell transcriptomics identifies CD36 as a negative regulator of osteogenic differentiation in murine osteoporosis

BACKGROUND: Osteoporosis is characterized by impaired osteogenic differentiation of bone marrow mesenchymal stem cells (BM-MSCs). The molecular regulators driving this impairment in murine models remain incompletely understood. OBJECTIVES: To identify key regulators of BM-MSC osteogenic differentiation in murine osteoporosis using single-cell transcriptomic analysis, and to validate the functional role of the identified candidate in vivo. METHODS: Single-cell RNA sequencing data from murine osteoporosis and osteoarthritis samples were analyzed to identify differentially expressed genes in BM-MSC subpopulations. CD36 was selected based on GO-KEGG enrichment analysis. Functional validation was performed in an ovariectomy mouse model using adeno-associated virus-mediated CD36 knockdown. Bone microarchitecture was assessed by micro-computed tomography and histomorphometry. Osteogenic capacity was evaluated by Western blot, immunofluorescence, and immunohistochemistry. RESULTS: CD36 was significantly upregulated in BM-MSCs from murine osteoporotic samples. CD36-positive BM-MSCs showed enrichment of the peroxisome proliferator-activated receptor signaling pathway and extracellular matrix-receptor interaction pathways. Adeno-associated virus-mediated CD36 knockdown in ovariectomized mice restored trabecular bone parameters and increased RUNX2-positive osteoprogenitor numbers compared to controls. CONCLUSIONS: CD36 acts as a negative regulator of osteogenic differentiation in murine BM-MSCs. Targeting CD36 may represent a therapeutic strategy for osteoporosis by restoring the osteogenic/adipogenic balance in bone marrow.