title: Role of protein kinase C and phosphoinositide 3-kinase-Akt in substance P-induced proinflammatory pathways in mouse macrophages.
abstract: Neuropeptide modulation of immune cell function is an important mechanism of neuro-immune intersystem crosstalk. Substance P (SP) is one such key neuropeptide involved. In this study, we investigated the yet unexplored cellular mechanisms of SP-mediated inflammatory responses in macrophages using a mouse macrophage-like cell line RAW 264.7 and isolated peritoneal macrophages. We found that the conventional PKCalpha and novel PKCdelta and epsilon were selectively activated by SP via its primary neurokinin-1 receptor (NK-1R) on the cells. Activation of these PKC isoforms mediated the activation of downstream extracellular signal-regulated kinase-1/2 (ERK1/2) and the transcription factor NF-kappaB, which drove the transcription of inducible chemokines in macrophages. Additionally, phosphoinositide 3-kinase (PI3K)-Akt was also activated by SP/NK-1R in macrophages. Inhibition of PI3K-Akt pathway attenuated ERK1/2 and NF-kappaB activation, suggesting it also played a part in SP-induced cellular inflammatory response. Kinetic analysis indicated that PKC isoforms induced early ERK1/2 activation, while PI3K-Akt contributed to the pathway at later time points. It was further demonstrated that PKC and PI3K-Akt were activated independent of each other. Collectively, our results suggest that SP/NK-1R activates two convergent proinflammatory signaling pathways, PKCs and PI3K-Akt, resulting in ERK1/2 and NF-kappaB activation and chemokine production in mouse macrophages.
authors.affiliation: Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Jia
authors.initials: J
authors.lastname: Sun
authors.forename: Raina Devi
authors.initials: RD
authors.lastname: Ramnath
authors.forename: Ramasamy
authors.initials: R
authors.lastname: Tamizhselvi
authors.forename: Madhav
authors.initials: M
authors.lastname: Bhatia
mesh_terms: D000818:Animals; D002460:Cell Line; D018925:Chemokines / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D007249:Inflammation / Q000378:metabolism; D007700:Kinetics; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018040:Receptors, Neurokinin-1 / Q000378:metabolism; D013373:Substance P / Q000494:pharmacology*
chemical_list: D018925:Chemokines; D048049:Extracellular Signal-Regulated MAP Kinases; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D020033:Protein Isoforms; D011493:Protein Kinase C; D047428:Protein Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D018040:Receptors, Neurokinin-1; D013373:Substance P