Effects And Mechanisms Of CD38-deficiency On LPS-mediated Expressions And Secretion Of Inflammatory Factors In Macrophages

Background and Objective: Atherosclerosis is an important cause of manycardiovascular diseases. Numerous experimental evidence and clinical resourcesindicated that inflammation reaction played an important role in the development ofatherosclerosis. The mechanisms are closely related with the inflammatory cellinfiltration, cytokine secretion, smooth muscle cell migration and foam cell formation.CD38is a multifunctional ectoenzyme that catalyzes the synthesis and hydrolysis ofcyclic ADP-ribose (cADPR) from NAD+to ADP-ribose. Our previous study showedthat the disruption of CD38in ApoE-/-mice could result in more severeatherosclerotic lesions. The aim of this thesis is to investigate the role and molecularmechanisms of CD38in macrophage activation. The findings would help to developnew effective strategies for prevention and treatment of atherosclerosis.Methods:1. Primary culture of macrophages. The wild-type and CD38knockout mice were intraperitoneally injected with0.5ml of3%sodium mercaptoe-thanol to induce the macrophages. After three days the peritoneal macrophages werecollected and cultured, and then identified for follow-up experiments.2. Geneexpression and inflammatory cytokine secretion of macrophages： The primaryperitoneal macrophages from both wild-type and CD38-/-mice were stimulated withor without1μg/ml of LPS. The mRNA levels of TLR4and related inflammatorycytokines such as TNF-α, IL-β and MCP-1were evaluated by real-time PCR. At thesame time the expression of NF-κB was analyzed by Western Blotting.Results:1. The identity of macrophages was confirmed by the cell morphologyexamination under the microscope.2. CD38-deficiency resulted in increase ofinflammatory cytokines and related protein expression after induced by LPS.①TheTLR4expression and cytokine secretion such as TNF-α，IL-1β and MCP-1weresignificantly increased after stimulation by LPS in both groups.②The expression ofTLR4and NF-κB were greatly increased in CD38-/-macrophage compared that withwild-type group.③.The secretion of TNF-α, IL-1β and MCP-1were sharplyincreased in CD38-/-macrophages after stimulated by LPS compared with that of WT. Conclusion: LPS significantly induced the M1inflammatory cytokine secretionin macrophages from CD38-/-mice, suggesting that CD38deficiency results inincreased inflammatory response of macrophages. Moreover, the TLR4-NF-κBpathway may be involved in CD38-mediated cytokine production in macrophages.