Protein expression after delivery of mRNA encoding PDGF-BB into rat gingiva: A Pilot Study

Abstract

Messenger RNA (mRNA) has been emerged as a novel therapeutic modality in medical fields, including regenerative medicine. The concept of mRNA-based therapy is the use of synthesized mRNA encoding a potentially therapeutic protein delivered into targeted tissue. Thus, utilizing mRNA encoding growth factor for protein replacement therapy could be a promising alternative to recombinant protein. Platelet-derived growth factor (PDGF) is one of most extensively studied growth factors for periodontal regeneration. To date, the potential of mRNA therapy has never been explored in the field of periodontal regeneration. The aim of the study is to examine the effect of nucleoside-modified mRNA encoding PDGF-BB on the level of PDGF-BB protein and the inflammatory response at local tissue upon intragingival injection. Sprague-Dawley rats were injected with pseudouridine-modified mRNA encoding PDGF-BB in sucrose citrate buffer at palatal gingiva. Gingiva were collected at days 1, 2, 3, 5 and 7 for protein analysis of PDGF-BB, VEGF-A protein and pro-inflammatory cytokines (IL-6 and TNF-a) in tissue homogenates. Enzyme-linked immunosorbent assay revealed that a single gingival injection of pseudouridine-modified mRNA encoding PDGF-BB significantly promoted transient PDGF-BB protein expression up to 40- to 100-fold as compared to control. PDGF-BB production peaked at 24-hour post-injection and declined to baseline within 3 days.  Neither IL-6 nor TNF-a in gingiva were affected. The findings from this study demonstrated that intragingival injection of pseudouridine-modified mRNA encoding PDGF-BB in sucrose citrate buffer results in transient PDGF protein production with minimal local immune response. mRNA technology might be a potential approach for periodontal regeneration.