# Alpha-Ketoglutarate Drives an Osteogenic and Extracellular Matrix Gene Program in Periodontal Ligament Fibroblasts via Selective Reduction of H3K27me3

## TL;DR

Alpha-ketoglutarate promotes periodontal tissue regeneration by selectively reducing a repressive gene signal in human and mouse models.

## Contribution

Alpha-ketoglutarate is shown to drive an osteogenic and extracellular matrix gene program via selective H3K27me3 reduction.

## Key findings

- Alpha-ketoglutarate increased ALP activity and upregulated osteogenesis and ECM-related genes in human periodontal ligament cells.
- Oral alpha-ketoglutarate enhanced alveolar bone regeneration and collagen-rich tissue formation in a mouse model.
- Alpha-ketoglutarate reduced H3K27me3 without broadly altering chromatin accessibility, indicating selective gene regulation.

## Abstract

Periodontal disease damages the tissues that support teeth and can ultimately lead to tooth loss, yet effective treatments to regenerate these tissues are still limited. Recent studies have shown that substances produced during normal cellular metabolism can influence how genes are regulated, but their role in periodontal regeneration has not been fully clarified. In this study, we investigated whether alpha-ketoglutarate, a naturally occurring metabolite involved in energy production, could promote periodontal tissue regeneration. We found that alpha-ketoglutarate enhanced bone-related and extracellular matrix-related gene expression in human periodontal ligament cells by reducing a repressive gene-regulatory signal that normally suppresses these genes. Importantly, alpha-ketoglutarate did not broadly alter chromatin accessibility, indicating that its effects were mediated through selective gene regulation. Furthermore, oral administration of alpha-ketoglutarate promoted alveolar bone regeneration and collagen-rich tissue formation in a mouse model of periodontal disease. Because alpha-ketoglutarate is a naturally occurring molecule in the body, these findings suggest that metabolite-based regulation of gene activity may represent a promising and safe approach for periodontal tissue regeneration.

Periodontal disease is a chronic inflammatory condition that destroys tooth-supporting tissues, particularly the alveolar bone and the periodontal ligament, and effective regenerative therapies remain limited. While the role of metabolic–epigenomic crosstalk in determining cell fate is well established, the specific mechanism by which a tricarboxylic acid (TCA) cycle metabolite can modulate chromatin regulation to promote periodontal regeneration remains to be elucidated. The impact of one TCA cycle metabolite, alpha-ketoglutarate (α-KG), was examined in human periodontal ligament fibroblasts cultured under osteogenic induction and profiled by ALP assays, RT-qPCR, analyses of multiple histone modifications, ATAC-seq, and RNA-seq. α-KG increased ALP activity and upregulated genes associated with osteogenesis and the extracellular matrix (ECM). ATAC-seq revealed minimal genome-wide accessibility changes, whereas histone analyses showed reduced H3K27me3, consistent with an epigenetic mechanism that does not require extensive chromatin opening. The RNA-seq identified 14 upregulated α-KG-induced genes, including multiple components of the OGN-OMD-PLAP1/ASPN-ECM2 loci, supporting an osteogenic/ECM transcriptional program. In a mouse periodontal regeneration model, oral administration of α-KG enhanced alveolar bone regeneration and reduced H3K27me3 signals and collagen-rich tissue organization within the periodontal ligament space. These findings identify α-KG as a metabolite-driven epigenetic modulator that alleviates H3K27me3-mediated repression and supports periodontal regeneration.