ASXL2 Modulates Chromatin Remodeling to Direct Osteogenesis and Multiple Cell Fate in hPDLSCs

Abstract

Aims

This study investigates the epigenetic role of Additional Sex Combs-Like 2 (ASXL2) in regulating osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs), aiming to address limitations in current strategies for oral and maxillofacial tissue regeneration.

Methods

Lentiviral-mediated ASXL2 knockdown in hPDLSCs was validated by flow cytometry. Functional impacts were assessed through proliferation/apoptosis assays, alkaline phosphatase (ALP) activity, Alizarin Red mineralization, and qPCR/Western blot analyses of osteogenic markers (RUNX2, ALP, COL1A1, OCN). Global histone modification dynamics (H2AK119ub, H3K27me3, H3K4me3) were detected to elucidate epigenetic mechanisms.

Results

ASXL2 depletion enhanced hPDLSC proliferation and reduced apoptosis, but critically impaired osteogenic differentiation, evidenced by suppressed ALP activity and mineralization. Global downregulation of osteogenic markers is correlated with altered chromatin states: decreased activating H3K4me3 and increased repressive H2AK119ub/H3K27me3.

Conclusion

ASXL2 modulates the osteogenic competency of hPDLSCs through epigenetic regulation, wherein its loss disrupts transcriptional accessibility by skewing histone modification balance: suppressing H3K4me3-mediated activation while amplifying H2AK119ub/H3K27me3-dependent repression to downregulate specific osteogenic genes.

Clinical Relevance

ASXL2 emerges as a pivotal epigenetic target for craniofacial regeneration. Strategic modulation of ASXL2 activity may optimize hPDLSC-based therapies to restore masticatory, pronunciation, and aesthetic functions.