Proinflammatory effects of muramyldipeptide on human gingival fibroblasts.
OBJECTIVE
Because human gingival fibroblasts (HGFs) are the predominant cells in periodontal tissues, we hypothesized that HGFs are contributed to receptors for components of bacteria. In this study, we focused on expression and function of nucleotide binding oligomerization domain 2 (NOD2) in HGFs, which is a mammalian cytosolic pathogen recognition molecule.


METHODS
Expression of NOD2 in HGFs was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometry. Production of interleukin (IL)-6, IL-8, cc chemokine ligand2, cxc chemokine ligand10 (CXCL10) and CXCL11 from HGFs was examined by enzyme-linked immunosorbent assay (ELISA). We used RT-PCR and immunohistochemistry to detect the NOD2 expression in human gingival tissues.


RESULTS
We found clear NOD2 expression in HGFs. Upon stimulation with NOD2 agonist, muramyldipeptide (MDP), production of proinflammatory cytokines was enhanced. Moreover, MDP-induced production of proinflammatory cytokines was inhibited in a different manner by mitogen-activated protein kinase inhibitors and phosphatidylinositol 3-kinase inhibitor. Furthermore, MDP enhanced CXCL10 and CXCL11 productions by tumor necrosis factor-alpha (TNF-alpha)- or interferon-gamma (IFN-gamma)-stimulated HGFs, although MDP alone did not induce these chemokines. TNF-alpha and IFN-gamma increased NOD2 expression in HGFs. In addition, we detected NOD2 expression in mononuclear cells and HGFs in periodontally diseased tissues.


CONCLUSIONS
These findings indicate that MDP which induces production of cytokines and chemokines from HGFs is related to the pathogenesis of periodontal disease.
Hosokawa
I
I
Department of Conservative Dentistry, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Tokushima, Japan. hosokawa@dent.tokushima-u.ac.jp
Hosokawa
Y
Y
Ozaki
K
K
Yumoto
H
H
Nakae
H
H
Matsuo
T
T
D000119:Acetylmuramyl-Alanyl-Isoglutamine / Q000494:pharmacology*; D000328:Adult; D000873:Anthracenes / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000032:analysis / Q000187:drug effects; D054357:Chemokine CXCL10 / Q000032:analysis / Q000187:drug effects; D054371:Chemokine CXCL11 / Q000032:analysis / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D055113:Chronic Periodontitis / Q000473:pathology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005347:Fibroblasts / Q000187:drug effects*; D005419:Flavonoids / Q000494:pharmacology; D005881:Gingiva / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D018836:Inflammation Mediators / Q000494:pharmacology*; D007371:Interferon-gamma / Q000494:pharmacology; D015850:Interleukin-6 / Q000032:analysis; D016209:Interleukin-8 / Q000032:analysis / Q000187:drug effects; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D008297:Male; D008875:Middle Aged; D009025:Morpholines / Q000494:pharmacology; D053473:Nod2 Signaling Adaptor Protein / Q000819:agonists* / Q000032:analysis / Q000187:drug effects; D017622:Periodontal Attachment Loss / Q000473:pathology; D010514:Periodontal Pocket / Q000473:pathology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011725:Pyridines / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000873:Anthracenes; D018932:Chemokine CCL2; D054357:Chemokine CXCL10; D054371:Chemokine CXCL11; D002867:Chromones; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D018836:Inflammation Mediators; D015850:Interleukin-6; D016209:Interleukin-8; D009025:Morpholines; C429018:NOD2 protein, human; D053473:Nod2 Signaling Adaptor Protein; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011725:Pyridines; D014409:Tumor Necrosis Factor-alpha; C432165:pyrazolanthrone; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D000119:Acetylmuramyl-Alanyl-Isoglutamine; D007371:Interferon-gamma; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one