In Vitro Evidence for Oral Soft Tissue Regenerative Effects of a Polynucleotide–Hyaluronan Formulation

Abstract

Objectives: We aimed to investigate the effects of a polynucleotide–hyaluronan (PN–HA) formulation on human palatal fibroblasts (HPFs) and oral epithelial cells (OKF6/TERT-2) to assess its potential application in oral soft tissue reconstructive procedures. Material and Methods: The impact of PN–HA on cell viability, migration, and proliferation was assessed using functional assays. Gene expression of wound healing-related growth factors, inflammatory cytokines, and keratinization markers was evaluated by qRT-PCR, while protein expression and kinase signaling were analyzed via immunofluorescence and immunoblotting. Results: PN–HA preserved cell viability and significantly (p < 0.05) enhanced migration of both HPFs and OKF6/TERT-2 compared to untreated control cells. While it significantly (p < 0.01) increased proliferation in HPFs, no direct proliferative effect was observed in OKF6/TERT-2 monocultures. In HPFs, PN–HA upregulated TGFB1, PDGFB, and FGF2 genes encoding the respective pro-migratory/pro-proliferative growth factors, whereas TGFB3 and EGF were selectively induced in OKF6/TERT-2. PN–HA markedly increased pro-inflammatory cytokine expression and activated p38 MAPK signaling in epithelial cells, alongside ERK1/2 activation and moderate increase in adenosine A2A receptor expression in both cell types. A pronounced upregulation of keratinocyte differentiation markers was observed at both mRNA and protein levels. Notably, in epithelial-fibroblast cocultures, PN–HA significantly (p < 0.01) enhanced epithelial proliferation, likely mediated by increased FGF7 and HGF expression in fibroblasts. Conclusions: PN–HA promotes oral fibroblast migration and proliferation, induces epithelial differentiation, and stimulates epithelial proliferation in coculture with fibroblasts. The observed cell- and context-specific effects highlight the potential of PN–HA to support soft tissue regeneration and keratinization in periodontal reconstructive surgeries.