IADR Abstract Archives
NAMPT Enzyme Activity Regulates Catabolic Gene Expression in Gingival Fibroblasts during Periodontitis
Objectives: Periodontal disease is one of the most prevalent chronic disorders worldwide. It is accompanied by inflammation of the gingiva and destruction of periodontal tissues and leads to alveolar bone loss. Here, we focused on the role of adipokines, locally expressed by periodontal tissues, in the regulation of catabolic gene expression leading to periodontal inflammation.
Methods: PD pathogenesis was determined in periodontal mouse model, an experimental mouse model and evaluated by H&E staining and IHC. Primary cultured human gingival fibroblast (HGF) originated from human were treated with FK-866 for intracellular NAMPT inhibition and anti-NAMPT antibody for extracellular NAMPT inhibition or were infected with adenovirus for NAMPT overexpression. Expression patterns of adipokines and cytokines were determined by western blotting and RT-PCR.
Results: The expression of the nicotinamide phosphoribosyltransferase (NAMPT) adipokine was dramatically increased in inflamed human and mouse gingival tissues. NAMPT expression was also increased in lipopolysaccharide- and proinflammatory cytokine-stimulated primary cultured human gingival fibroblasts (GF). Adenovirus-mediated NAMPT (Ad-Nampt) overexpression upregulated the expression and activity of COX-2, MMP1, and MMP3 in human GF. Upregulation of IL-1b- or Ad-Nampt-induced catabolic factors was significantly abrogated by the intracellular NAMPT (iNAMPT) inhibitor, FK866, or by the sirtuin (SIRT) inhibitor, nicotinamide (NIC), whereas recombinant NAMPT protein or extracellular NAMPT (eNAMPT) inhibition using a blocking antibody did not alter NAMPT target gene expression levels. Moreover, intragingival Ad-Nampt injection mediated periodontitis-like phenotypes, including alveolar bone loss, in mice. SIRT2 among SIRT family members was positively associated with NAMPT actions in human GF. Furthermore, in vivo inhibition of the NAMPT-NAD+-SIRT axis by NIC injection in mice ameliorated the periodontal inflammation and alveolar bone erosion caused by intragingival injection of Ad-Nampt.
Conclusions: Our findings indicate that NAMPT is highly upregulated in human GF and its enzymatic activity acts as a crucial mediator of periodontal inflammation and alveolar bone destruction via regulation of COX-2, MMP1, and MMP3 levels.
Methods: PD pathogenesis was determined in periodontal mouse model, an experimental mouse model and evaluated by H&E staining and IHC. Primary cultured human gingival fibroblast (HGF) originated from human were treated with FK-866 for intracellular NAMPT inhibition and anti-NAMPT antibody for extracellular NAMPT inhibition or were infected with adenovirus for NAMPT overexpression. Expression patterns of adipokines and cytokines were determined by western blotting and RT-PCR.
Results: The expression of the nicotinamide phosphoribosyltransferase (NAMPT) adipokine was dramatically increased in inflamed human and mouse gingival tissues. NAMPT expression was also increased in lipopolysaccharide- and proinflammatory cytokine-stimulated primary cultured human gingival fibroblasts (GF). Adenovirus-mediated NAMPT (Ad-Nampt) overexpression upregulated the expression and activity of COX-2, MMP1, and MMP3 in human GF. Upregulation of IL-1b- or Ad-Nampt-induced catabolic factors was significantly abrogated by the intracellular NAMPT (iNAMPT) inhibitor, FK866, or by the sirtuin (SIRT) inhibitor, nicotinamide (NIC), whereas recombinant NAMPT protein or extracellular NAMPT (eNAMPT) inhibition using a blocking antibody did not alter NAMPT target gene expression levels. Moreover, intragingival Ad-Nampt injection mediated periodontitis-like phenotypes, including alveolar bone loss, in mice. SIRT2 among SIRT family members was positively associated with NAMPT actions in human GF. Furthermore, in vivo inhibition of the NAMPT-NAD+-SIRT axis by NIC injection in mice ameliorated the periodontal inflammation and alveolar bone erosion caused by intragingival injection of Ad-Nampt.
Conclusions: Our findings indicate that NAMPT is highly upregulated in human GF and its enzymatic activity acts as a crucial mediator of periodontal inflammation and alveolar bone destruction via regulation of COX-2, MMP1, and MMP3 levels.