Shanshan Gao1, Juan Zhou2, Na Liu3, Lijun Wang2, Qiyue Gao1, Yan Wu1, Qiang Zhao1, Peining Liu1, Shun Wang1, Yan Liu1, Ning Guo1, Yan Shen4, Yue Wu5, Zuyi Yuan6. 1. Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi, China. 2. Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi, China; Key Laboratory of Molecular Cardiology Xi'an Jiaotong University, Xi'an 710061, Shaanxi, China. 3. Department of Cardiovascular Medicine, The Second Hospital of Yulin, Yulin 719000, Shaanxi, China. 4. Department of Nephrology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi, China. 5. Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi, China. Electronic address: imyuewu@gmail.com. 6. Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi, China; Key Laboratory of Molecular Cardiology Xi'an Jiaotong University, Xi'an 710061, Shaanxi, China; Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University Ministry of Education, Xi'an 710061, Shaanxi, China. Electronic address: zuyiyuan@mail.xjtu.edu.cn.
Abstract
AIMS: To address the underlying mechanisms by which curcumin facilitates M2 phenotype polarization of macrophages and its roles in the protective effects during experimental autoimmune myocarditis (EAM). METHODS AND RESULTS: The expression of classic M2 markers, including macrophage mannose receptor (MMR), arginase-1 (Arg-1) and peroxisome proliferator-activated receptor-γ (PPAR-γ) was upregulated in curcumin-treated Raw264.7 macrophages. Curcumin increased interleukin-4 (IL-4) and interleukin-13 (IL-13) mRNA expression and protein secretion. Curcumin notably increased STAT6 phosphorylation. Leflunomide, a STAT6 inhibitor, and IL-4 and/or IL-13 neutralizing antibodies antagonized the induction of MMR, Arg-1 and PPAR-γ by curcumin in Raw264.7 cells. In vivo, 6-week old male Lewis rats were used to induce EAM and orally administrated with curcumin or corn oil for 3weeks after myosin injection. Cardiac functional parameters, including left ventricular fractional shortening (LVFS), ejection fraction (EF), left ventricular end-systolic diameter (LVEDs) and heart rate (HR) were significantly improved by curcumin treatment. Curcumin also reduced the inflammatory cell infiltration and myocardial mRNA levels of interleukin-1β (IL-1β) and inducible nitric oxide synthase (iNOS). Meanwhile, the myocardial mRNA levels of MMR and Arg-1 were markedly up-regulated by curcumin. Immunofluorescence assay showed that the number of CD68(+) MMR(+) and CD68(+) Arg-1(+) double positive macrophages in curcumin-treated myocardial tissue was significantly higher than untreated control. The number of CD68(+) iNOS(+) double positive macrophages was increased obviously in EAM group, but decreased markedly by curcumin treatment. CONCLUSIONS: Taken together, these results show that curcumin induces macrophage M2 polarization by secretion of IL-4 and/or IL-13. Curcumin ameliorates EAM by reducing infiltration inflammatory macrophages and by polarizing M0 and M1 macrophages to M2 phenotype.
AIMS: To address the underlying mechanisms by which curcumin facilitates M2 phenotype polarization of macrophages and its roles in the protective effects during experimental autoimmune myocarditis (EAM). METHODS AND RESULTS: The expression of classic M2 markers, including macrophage mannose receptor (MMR), arginase-1 (Arg-1) and peroxisome proliferator-activated receptor-γ (PPAR-γ) was upregulated in curcumin-treated Raw264.7 macrophages. Curcumin increased interleukin-4 (IL-4) and interleukin-13 (IL-13) mRNA expression and protein secretion. Curcumin notably increased STAT6 phosphorylation. Leflunomide, a STAT6 inhibitor, and IL-4 and/or IL-13 neutralizing antibodies antagonized the induction of MMR, Arg-1 and PPAR-γ by curcumin in Raw264.7 cells. In vivo, 6-week old male Lewis rats were used to induce EAM and orally administrated with curcumin or corn oil for 3weeks after myosin injection. Cardiac functional parameters, including left ventricular fractional shortening (LVFS), ejection fraction (EF), left ventricular end-systolic diameter (LVEDs) and heart rate (HR) were significantly improved by curcumin treatment. Curcumin also reduced the inflammatory cell infiltration and myocardial mRNA levels of interleukin-1β (IL-1β) and inducible nitric oxide synthase (iNOS). Meanwhile, the myocardial mRNA levels of MMR and Arg-1 were markedly up-regulated by curcumin. Immunofluorescence assay showed that the number of CD68(+) MMR(+) and CD68(+) Arg-1(+) double positive macrophages in curcumin-treated myocardial tissue was significantly higher than untreated control. The number of CD68(+) iNOS(+) double positive macrophages was increased obviously in EAM group, but decreased markedly by curcumin treatment. CONCLUSIONS: Taken together, these results show that curcumin induces macrophage M2 polarization by secretion of IL-4 and/or IL-13. Curcumin ameliorates EAM by reducing infiltration inflammatory macrophages and by polarizing M0 and M1 macrophages to M2 phenotype.