Laser-activated transforming growth factor-β1 induces human β-defensin 2: implications for laser therapies for periodontitis and peri-implantitis

J Periodontal Res. 2017 Jun;52(3):360-367. doi: 10.1111/jre.12399. Epub 2016 Jul 11.

Abstract

Background: There is increasing popularity of high-power lasers for surgical debridement and antimicrobial therapy in the management of peri-implantitis and periodontal therapy. Removal of the noxious foci would naturally promote tissue healing directly. However, there are also anecdotal reports of better healing around routine high-power laser procedures. The precise mechanisms mediating these effects remain to be fully elucidated. This work examines these low-dose laser bystander effects on oral human epithelial and fibroblasts, particularly focusing on the role of human β-defensin 2 (HBD-2 or DEFB4A), a potent factor capable of antimicrobial effects and promoting wound healing.

Material and methods: Laser treatments were performed using a near-infrared laser (810 nm diode) at low doses. Normal human oral keratinocytes and fibroblast cells were used and HBD-2 mRNA and protein expression was assessed with real time polymerase chain reaction, western blotting and immunostaining. Role of transforming growth factor (TGF)-β1 signaling in this process was dissected using pathway-specific small molecule inhibitors.

Results: We observed laser treatments robustly induced HBD-2 expression in an oral fibroblast cell line compared to a keratinocyte cell line. Low-dose laser treatments results in activation of the TGF-β1 pathway that mediated HBD-2 expression. The two arms of TGF-β1 signaling, Smad and non-Smad are involved in laser-mediated HBD-2 expression.

Conclusions: Laser-activated TGF-β1 signaling and induced expression of HBD-2, both of which are individually capable of promoting healing in tissues adjacent to high-power surgical laser applications. Moreover, the use of low-dose laser therapy itself can provide additional therapeutic benefits for effective clinical management of periodontal or peri-implant disease.

Keywords: defensins; lasers; low-level light/laser therapy; peri-implantitis; periodontitis; photobiomodulation therapy.

MeSH terms

  • Blotting, Western
  • Fibroblasts / metabolism
  • Fibroblasts / radiation effects
  • Humans
  • Keratinocytes / metabolism
  • Keratinocytes / radiation effects
  • Low-Level Light Therapy* / methods
  • Peri-Implantitis / radiotherapy*
  • Periodontitis / radiotherapy*
  • Real-Time Polymerase Chain Reaction
  • Transforming Growth Factor beta1 / metabolism*
  • beta-Defensins / metabolism*

Substances

  • DEFB4A protein, human
  • Transforming Growth Factor beta1
  • beta-Defensins