Hif-1A Enhance Regenerative Capacity Of LepR+ Cells In Periodontium

Based on previous identification of LepR+ cells as promising seed cells in periodontal healing post periodontitis, we aim to further explore the molecular mechanisms of HIF-1A in regulating the generative capacity of LepR+ cells in this study. We used LepR+ periodontal ligament stem cells isolated via FACS from human 3rd molars (hPDLSCs) and LepRCre/+; R26RtdTomato/+ transgenic mice (male, 8 weeks old) to perform in vitro and in vivo experiments (Approval number: WCHSIRB-D-2023-333 and WCHSIRB-D-2023-174). Deferoxamine Mesylate (DFM), a HIF-1A stabilizer was used to induce upregulation of HIF-1A in periodontium. Micro-CT, histological and immunostaining, scratch assay, small RNA interference and other techniques were adopted to comprehensively test the migration and osteogenic differentiation of LepR+ cells in- and post periodontitis. Elevated HIF-1A expression in LepR+ cells was confirmed in vitro and in vivo after removal of local inflammatory stimuli, which is consistent with previous RNAseq data. Scratch assay and downregulated CXCR4 expression of LepR+ cells showed compromised migration ability when HIF-1A expression was interrupted by siRNA. In addition, osteogenic differentiation was impaired due to reduced HIF-1A level indicated by decreased ALP expression. Locally applied DFM significantly elevated RUNX2 expression in periodontium and increased the number of LepR+ cells as well as CXCR4-expressing cells in PDL, notably ameliorated periodontal destruction caused by ligature-induced inflammation. HIF-1A plays a necessary role in promoting periodontal healing and regeneration via improving the migration and osteogenic differentiation of LepR+ cells.