Jin Geng1, Chenchen Yang2, Bingjian Wang1, Xiwen Zhang1, Tingting Hu1, Yang Gu1, Ju Li3. 1. Department of Cardiology, Huai'an First People's Hospital, Nanjing Medical University, Huai'an Jiangsu, China. 2. Department of Emergency Medicine, Huai'an First People's Hospital, Nanjing Medical University, Huai'an, Jiangsu, China. 3. Department of Rheumatology, Huai'an First People's Hospital, Nanjing Medical University, Huai'an, Jiangsu, China. Electronic address: liju198461@163.com.
Abstract
BACKGROUND: Many studies have identified trimethylamine N-oxide (TMAO) as a new risk factor of cardiovascular diseases. It has been suggested that TMAO promotes atherosclerosis development. However, the underlying mechanism is still unclear. METHODS: Apoe-/- mice were fed a high-fat diet and given water with or without TMAO for 8-week. Histological and immunohistological analyses were used to evaluate the atherogenic effect of TMAO in vivo. We also employed peritoneal elicited macrophages and RAW264.7 to assess the role of MAPK/JNK pathway in TMAO-induced formation of foam cells. RESULTS: TMAO significantly promoted plaque progression in apoe-/- mice fed with high-fat diet for 8 weeks. Besides, macrophage recruitment, CD36 and proinflammatory cytokine expressions were enhanced by TMAO in plaque lesions. In vitro, TMAO increased the macrophage migration and the expression of TNF-α, IL-6 and ICAM1. In addition, CD36 expression and foam cell formation induced by ox-LDL were also enhanced by TMAO, which could be attenuated by siRNA-mediated knockdown of CD36. We additionally used MAPK inhibitor (SB230580) and JNK inhibitor (SP600125) to assess the MAPK/JNK pathway in TMAO-induced CD36 expression. Western blotting showed that both SB230580 and SP600125 could reduce the expression of CD36 induced by ox-LDL and TMAO. Moreover, SB230580 and SP600125 could also reduce the formation of foam cells. CONCLUSIONS: TMAO promotes the atherosclerosis in vivo and in vitro.CD36/MAPK/JNK pathway may play a crucial role in TMAO-induced formation of foam cells.
BACKGROUND: Many studies have identified trimethylamine N-oxide (TMAO) as a new risk factor of cardiovascular diseases. It has been suggested that TMAO promotes atherosclerosis development. However, the underlying mechanism is still unclear. METHODS:Apoe-/- mice were fed a high-fat diet and given water with or without TMAO for 8-week. Histological and immunohistological analyses were used to evaluate the atherogenic effect of TMAO in vivo. We also employed peritoneal elicited macrophages and RAW264.7 to assess the role of MAPK/JNK pathway in TMAO-induced formation of foam cells. RESULTS:TMAO significantly promoted plaque progression in apoe-/- mice fed with high-fat diet for 8 weeks. Besides, macrophage recruitment, CD36 and proinflammatory cytokine expressions were enhanced by TMAO in plaque lesions. In vitro, TMAO increased the macrophage migration and the expression of TNF-α, IL-6 and ICAM1. In addition, CD36 expression and foam cell formation induced by ox-LDL were also enhanced by TMAO, which could be attenuated by siRNA-mediated knockdown of CD36. We additionally used MAPK inhibitor (SB230580) and JNK inhibitor (SP600125) to assess the MAPK/JNK pathway in TMAO-induced CD36 expression. Western blotting showed that both SB230580 and SP600125 could reduce the expression of CD36 induced by ox-LDL and TMAO. Moreover, SB230580 and SP600125 could also reduce the formation of foam cells. CONCLUSIONS:TMAO promotes the atherosclerosis in vivo and in vitro.CD36/MAPK/JNK pathway may play a crucial role in TMAO-induced formation of foam cells.