Targeting high mobility group protein B2 exerts antiproliferative effects in hypoxic pulmonary hypertension by...

Pulmonary hypertension (PH) is characterized by excessive vascular cell proliferation, leading to vascular remodeling. In this study, we aimed to investigate the molecular mechanisms underlying the regulation of vascular cell proliferation in the context of HMGB2 and its potential involvement in the pathogenesis of PH.

Animals and pulmonary vascular smooth muscle cells (PASMCs) were exposed to hypoxia. Pathological changes in pulmonary vessels were detected by HE and Masson staining. The effect of HMGB2 on cell proliferation was detected by siRNA transfections and recombinant protein treatment. miR-21 inhibitor and mimics were applied, and TPM1 expression was detected. HMGB2^-/- mice were applied to observe the possible preventive effect of HMGB2 in PH development.

HMGB2 expression was increased in hypoxic rats and PASMCs. Silencing ZDHHC5 reduced HMGB2 expression and cell proliferation. Cell proliferation was inhibited by knocking down HMGB2 and promoted by its over-expression. Hypoxia-induced miR-21 upregulation and TPM1 downregulation were mediated by HMGB2. 8-Br-cGMP suppressed HMGB2-induced PASMC proliferation and increased SOX2 expression by activating the cGMP/PKG signaling pathway. HMGB2^-/- attenuated pulmonary vascular remodeling and fibrosis in hypoxia induced PH mice.

HMGB2 promotes PASMC proliferation through the cGMP/PKG-SOX2-miR-21-TPM1 pathway, which provides a new theoretical basis and possible targets for the pathogenesis and clinical prevention of PH.