PPARγ delivered by Ch-GNPs onto titanium surfaces inhibits implant-induced inflammation and induces bone mineralization of MC-3T3E1 osteoblast-like cells.
OBJECTIVE
To deliver the efficacy and safety of Ch-GNPs (Chitosan gold nanoparticles) conjugated anti-inflammatory molecules peroxisome proliferator activated receptor gamma (PPARγ) on implant surface titanium (Ti) to reduce implant-induced inflammation.


METHODS
The Ch-GNPs were conjugated with the PPARγ cDNA through a coacervation process. Conjugation was cast over Ti surfaces by dipping, and cells were seeded on different sizes (6 × 6 × 0.1 cm and 1 × 1 × 0.1 cm; n = 3) of Ti surfaces. The size of Ch-GNPs and surface characterization of Ti was performed using UV-vis spectroscopy, TEM (Transmission electron microscopy) and EDX (energy-dispersive X-ray). The DNA conjugation and transfection capacity of Ch-GNPs were simultaneously confirmed by agarose gel electrophoresis, β-galactosidase staining, and immunoblotting.


RESULTS
The Ch-GNPs were well dispersed and spherical in shape, with average size around 10-20 nm. Ti surfaces coated with Ch-GNPs/LacZ, as transfection efficacy molecule, showed strong β-galactosidase staining in MC-3T3 E1 cells. Cells cultured on Ch-GNPs/PPARγ-coated Ti surfaces were able to inhibit implant-induced inflammation by simultaneously suppressing the expression of tumor necrosis factor- alpha (TNF-α), interleukin-1 beta (IL-1β), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and matrix metalloproteinase-2 (MMP-2). The inhibition mechanism of Ch-GNPs/PPARγ was due to inhibition of both reactive oxygen species (ROS) and nitric oxide (NO) secretion (n = 3; P < 0.05). In addition, Ch-GNPs/PPARγ was able to increase expression of bone morphogenetic protein (BMP-7) and runt-related transcription factor-2 (RUNX-2). Furthermore, alkaline phosphatase activity (ALP) was also increased than that in control (n = 3; P < 0.01). Whereas, expression of receptor activator of NF-κB ligand (RANKL) was decreased.


CONCLUSIONS
The novel gene delivery materials, like Ch-GNPs, can carry the PPARγ cDNA into the required areas of the implant surfaces, thus aiding to inhibit inflammation and promote osteoblast function. Thus, the PPARγ on implant surfaces may promote its clinical application on peri-implantitis or periodontitis like diseases.
Department of Oral Biochemistry, Institute of Oral Bioscience, BK21 program, School of Dentistry, Chonbuk National University, Jeonju, Korea.
Govinda
G
Bhattarai
Young-Hee
YH
Lee
Nan-Hee
NH
Lee
Il-Song
IS
Park
Min-Ho
MH
Lee
Ho-Keun
HK
Yi
D016475:3T3 Cells / Q000187:drug effects* / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002113:Calcification, Physiologic / Q000187:drug effects*; D048271:Chitosan / Q000494:pharmacology*; D004587:Electrophoresis, Agar Gel; D006046:Gold / Q000494:pharmacology*; D051379:Mice; D053758:Nanoparticles; D009569:Nitric Oxide / Q000378:metabolism; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D047495:PPAR gamma / Q000494:pharmacology*; D057873:Peri-Implantitis / Q000517:prevention & control*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D013194:Staining and Labeling; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D014162:Transfection
D047495:PPAR gamma; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D006046:Gold; D048271:Chitosan; D014025:Titanium; D000469:Alkaline Phosphatase