Nod2 and Rip2 contribute to innate immune responses in mouse neutrophils.
Nod-like receptors are a family of innate immune receptors that link cytosolic sensing of microbial and danger stimuli to the activation of immune responses. Two Nod-like receptor family members, Nod1 and Nod2, recognize bacterial peptidoglycan and activate immune responses via nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK). The function of Nod1 and Nod2 has been largely studied in macrophages, but the role of these receptors in other innate immune cells remains unclear. In this study, we examined the function of Nod1 and Nod2 in innate immune responses of neutrophils. Mice were injected intraperitoneally with thioglycollate, and then peritoneal neutrophils were isolated 4 hr after injection. Tri-DAP and muramyl-dipeptide (MDP) were used as Nod1 and Nod2 agonists, respectively. The level of cytokines [interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α)] and chemokines (CXCL1 and CCL2) was increased by MDP, but not Tri-DAP in wild-type (WT) neutrophils. Increased production of cytokines and chemokines with MDP was abolished in Nod2- and Rip2-deficient neutrophils. MDP also induced the activation of NF-κB and MAPK in WT neutrophils, but not in Nod2- and Rip2-deficient cells. Flow cytometry analysis showed that L-selectin shedding was induced by MDP in WT neutrophils, but not in Nod2- and Rip2-deficient cells. MDP and Toll-like receptor (TLR) agonists (Pam3 CSK4 and lipopolysaccharide) exerted synergistic effects on the production of IL-6 and CXCL1 in neutrophils. Moreover, Nod2 and TLR4 cooperated to produce IL-6, TNF-α, CXCL1 and CCL2 in neutrophils in response to Gram-negative bacteria. Our findings suggest that the Nod2-Rip2 axis may contribute to the innate immune response of neutrophils against bacterial infection.
Department of Biochemistry, College of Medicine, Konyang University, Daejeon, Korea.
Yu-Jin
YJ
Jeong
Min-Jung
MJ
Kang
Sang-Jin
SJ
Lee
Chang-Hwan
CH
Kim
Jee-Cheon
JC
Kim
Tae-Hyoun
TH
Kim
Dong-Jae
DJ
Kim
Donghyun
D
Kim
Gabriel
G
Núñez
Jong-Hwan
JH
Park
D000119:Acetylmuramyl-Alanyl-Isoglutamine / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism; D054360:Chemokine CXCL1 / Q000378:metabolism; D003960:Diaminopimelic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D007113:Immunity, Innate / Q000187:drug effects; D015850:Interleukin-6 / Q000378:metabolism; D019041:L-Selectin / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008089:Listeria monocytogenes / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D018375:Neutrophil Activation / Q000187:drug effects; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D053474:Nod1 Signaling Adaptor Protein / Q000819:agonists / Q000378:metabolism; D053473:Nod2 Signaling Adaptor Protein / Q000819:agonists / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015011:Yersinia pseudotuberculosis / Q000276:immunology
C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D054360:Chemokine CXCL1; C475895:Cxcl1 protein, mouse; D015850:Interleukin-6; C555437:L-Ala-gamma-D-Glu-meso-diaminopimelic acid; D008070:Lipopolysaccharides; D016328:NF-kappa B; D053474:Nod1 Signaling Adaptor Protein; C507873:Nod1 protein, mouse; D053473:Nod2 Signaling Adaptor Protein; C495945:Nod2 protein, mouse; D009842:Oligopeptides; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; C577686:interleukin-6, mouse; C440499:lipopolysaccharide, Escherichia coli O111 B4; D019041:L-Selectin; D000119:Acetylmuramyl-Alanyl-Isoglutamine; D003960:Diaminopimelic Acid; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; C506255:Ripk2 protein, mouse; D020928:Mitogen-Activated Protein Kinases
Nod2; Rip2; immune response; muramyl dipeptide; neutrophils