Background: The complement system is important in development of atherosclerosis via regulation of lipid and glucose metabolism as well as inflammation. Aim: The aim of the present study was to further analyze the con...Background: The complement system is important in development of atherosclerosis via regulation of lipid and glucose metabolism as well as inflammation. Aim: The aim of the present study was to further analyze the contribution of C5L2 to the development of atherosclerosis. We proposed that, with DIO feeding, C5L2 deficiency would promote a phenotype that encourages atherosclerosis development. Coupled to ApoE deficiency, double knockout (2KO) mice would show exacerbated atherosclerotic plaque formation. Methods: First, Wildtype (WT) and C5L2-/-(C5L2KO) and subsequently, ApoE-/-(ApoEKO) and C5L2/ApoE double knockout mice were placed on diets inducing obesity (DIO) or standard chow diet for 12 - 15 weeks. Plasma lipids, glucose, cytokines and hepatic glycogen and lipid contents, mRNA levels and enzyme activities and atherosclerotic plaque size were measured. Results: C5L2KO had increased hepatic glucose oxidation (+90%, p < 0.001), reduced liver glycogen content on chow diet (-34%, p < 0.05) but increased with DIO (+51%, p < 0.05) vs WT. Glucose clearance was delayed in C5L2/ApoE-2KO vs ApoEKO mice with chow (p < 0.0001) and DIO diet (p = 0.0026). C5L2KO mice had increased hepatic lipid content and fatty acid synthesis but decreased lipid oxidation vs WT. Plasma cholesterol was further elevated in C5L2/ApoE-2KO vs ApoEKO with DIO feeding (p < 0.05). Hepatic cytokine expression was increased in C5L2KO mice compared to WT mice. Atherosclerotic plaque size was increased in C5L2/ ApoE-2KO mice compared with apoEKO on chow (p < 0.05) and DIO regimen (p < 0.001). Conclusions: C5L2 disruption worsens glucose and lipid metabolism, increases hepatic and circulating inflammation, and aggravates atherosclerosis.展开更多
The innate immune response is a complex process involving multiple pathogen-recognition receptors, including toll-like receptors (TLRs) and nucleotide-binding oligomerization domain (NOD)-like receptors. Complement is...The innate immune response is a complex process involving multiple pathogen-recognition receptors, including toll-like receptors (TLRs) and nucleotide-binding oligomerization domain (NOD)-like receptors. Complement is also a critical component of innate immunity. While complement is known to interact with TLR-mediated signals, the interactions between NOD-like receptors and complement are not well understood. Here we report a synergistic interaction between C5a and Nod2 signaling in RAW 264.7 marophages. Long-term treatment with muramyl dipeptide (MDP), a NOD2 ligand, enhanced C5a-mediated expression of chemokine mRNAs in RAW 264.7 cells. This response was dependent on NOD2 expression and was associated with a decrease in expression of C5L2, a receptor for C5a which acts as a negative modulator of C5a receptor (C5aR) activity. MDP amplified C5a-mediated phosphorylation of p38 MAPK. Treatment of RAW264.7 cells with an inhibitor of p38 attenuated the synergistic effects of C5aon MDP-primed cells on MIP-2, but not MCP-1, mRNA. In contrast, inhibition of AKT prevented C5a stimulation of MCP-1, but not MIP-2, mRNA, in MDP-primed cells. Taken together, these data demonstrated a synergistic interaction between C5a and NOD2 in the regulation of chemokine expression in macrophages, associated with a down-regulation of C5L2, a negative regulator of C5a receptor activity.展开更多
文摘Background: The complement system is important in development of atherosclerosis via regulation of lipid and glucose metabolism as well as inflammation. Aim: The aim of the present study was to further analyze the contribution of C5L2 to the development of atherosclerosis. We proposed that, with DIO feeding, C5L2 deficiency would promote a phenotype that encourages atherosclerosis development. Coupled to ApoE deficiency, double knockout (2KO) mice would show exacerbated atherosclerotic plaque formation. Methods: First, Wildtype (WT) and C5L2-/-(C5L2KO) and subsequently, ApoE-/-(ApoEKO) and C5L2/ApoE double knockout mice were placed on diets inducing obesity (DIO) or standard chow diet for 12 - 15 weeks. Plasma lipids, glucose, cytokines and hepatic glycogen and lipid contents, mRNA levels and enzyme activities and atherosclerotic plaque size were measured. Results: C5L2KO had increased hepatic glucose oxidation (+90%, p < 0.001), reduced liver glycogen content on chow diet (-34%, p < 0.05) but increased with DIO (+51%, p < 0.05) vs WT. Glucose clearance was delayed in C5L2/ApoE-2KO vs ApoEKO mice with chow (p < 0.0001) and DIO diet (p = 0.0026). C5L2KO mice had increased hepatic lipid content and fatty acid synthesis but decreased lipid oxidation vs WT. Plasma cholesterol was further elevated in C5L2/ApoE-2KO vs ApoEKO with DIO feeding (p < 0.05). Hepatic cytokine expression was increased in C5L2KO mice compared to WT mice. Atherosclerotic plaque size was increased in C5L2/ ApoE-2KO mice compared with apoEKO on chow (p < 0.05) and DIO regimen (p < 0.001). Conclusions: C5L2 disruption worsens glucose and lipid metabolism, increases hepatic and circulating inflammation, and aggravates atherosclerosis.
文摘The innate immune response is a complex process involving multiple pathogen-recognition receptors, including toll-like receptors (TLRs) and nucleotide-binding oligomerization domain (NOD)-like receptors. Complement is also a critical component of innate immunity. While complement is known to interact with TLR-mediated signals, the interactions between NOD-like receptors and complement are not well understood. Here we report a synergistic interaction between C5a and Nod2 signaling in RAW 264.7 marophages. Long-term treatment with muramyl dipeptide (MDP), a NOD2 ligand, enhanced C5a-mediated expression of chemokine mRNAs in RAW 264.7 cells. This response was dependent on NOD2 expression and was associated with a decrease in expression of C5L2, a receptor for C5a which acts as a negative modulator of C5a receptor (C5aR) activity. MDP amplified C5a-mediated phosphorylation of p38 MAPK. Treatment of RAW264.7 cells with an inhibitor of p38 attenuated the synergistic effects of C5aon MDP-primed cells on MIP-2, but not MCP-1, mRNA. In contrast, inhibition of AKT prevented C5a stimulation of MCP-1, but not MIP-2, mRNA, in MDP-primed cells. Taken together, these data demonstrated a synergistic interaction between C5a and NOD2 in the regulation of chemokine expression in macrophages, associated with a down-regulation of C5L2, a negative regulator of C5a receptor activity.
