Prolyl-hydroxylase domain inhibition enhances collagen levels in oral mucosa-derived fibroblasts

Fibroblast cells are a primary source of Collagen, playing a vital role in maintaining the structural integrity of the oral mucosa. Given that hypoxia upregulates Collagen levels in oral mucosa-derived fibroblasts (OMDFs), this study aims to investigate the effect of inhibiting prolyl-hydroxylase domain (PHD) Enzymes, negative regulators of the transcription factor hypoxia-inducible factor (HIF), on collagen-I levels under normal oxygen levels. We examined three PHD inhibitors, IOX4, Enarodustat, and Daprodustat, for their effect on Collagen levels in keratinized OMDFs. While IOX4 exhibited cellular cytotoxicity, Enarodustat and Daprodustat did not affect cell viability. Further treatment with Daprodustat at 12.5 or 25 μM significantly increased Collagen I level more than twofold compared to non-treated cells, whereas Enarodustat had no significant effect. Additional mechanistic studies revealed that Daprodustat treatment induced the accumulation and nuclear translocation of HIF-1α and upregulated transcripts of key collagen-modifying Enzymes, including P4HA1 and P4HA2, by more than twofold. This study demonstrates that direct PHD inhibition effectively enhances Collagen biosynthesis in OMDFs. The mechanism involves HIF-1α-mediated upregulation of collagen-modifying Enzymes. These findings highlight the potential of repurposing clinically approved PHD inhibitors as therapeutic agents for promoting the healing and regeneration of damaged gingiva and additional tissues.

Collagen biosynthesis; Hypoxia-inducible factor; Oral mucosa-derived fibroblasts; Periodontal tissue regeneration; Prolyl-hydroxylase domain inhibitors.