Shui-ping Zhao1, Jun Yang, Jing Li, Shao-zhuang Dong, Zhi-hong Wu. 1. Department of Cardiology, The Second Xiangya Hospital of Central South University, Middle Ren-Min Road No. 86, Changsha, Hunan 410011, PR China. zhaosp@medmail.com.cn
Abstract
BACKGROUND: Adipose tissue contains a large amount of cholesterol and performs a buffer function for circulating cholesterol. Liver X receptors (LXR) alpha and peroxisome proliferator-activated receptor gamma (PPARgamma) might play a significant role in adipocyte cholesterol metabolism through mediation of cholesterol efflux. The aim of this study was to evaluate the effect of niacin on LXRalpha and PPARgamma expression and HDL-induced cholesterol efflux in adipocytes from hypercholesterolemic rabbits. METHODS: Twelve rabbits fed with high-cholesterol diet for 8 weeks were randomly divided into two groups: (1) high cholesterol group (n=6): maintained high cholesterol diet for 6 weeks; (2) niacin group (n=6): the same cholesterol diet plus niacin (200 mg/kg/d) for 6 weeks. Control group (n=6) was fed with normal diet for 14 weeks. Subcutaneous adipose was collected for adipocyte culture. Reverse transcription polymerase chain reaction (RT-PCR) was used to evaluate adipocytes LXRalpha mRNA expressions. Cholesterol efflux rate was determined through measuring release of radioactivity from (3)H-cholesterol prelabeled cells into medium containing high-density lipoprotein (HDL). The direct effect of niacin on LXRalpha and PPARgamma mRNA expression in primary rabbit adipocytes was assayed. RESULTS: High cholesterol diet resulted in decreased LXRalpha mRNA expressions and reduced HDL-induced cholesterol efflux rate in adipocytes. Six weeks of niacin treatment significantly enhanced the cholesterol efflux from adipocytes, which was related to the increased mRNA expressions of LXRalpha (r=0.71, P<0.05). In in vitro study, niacin dose-dependently stimulated LXRalpha and PPARgamma mRNA expression in cultured adipocytes. And various doses of niacin-induced cholesterol efflux was positive correlation with LXRalpha and PPARgamma mRNA expression (r=0.83 P<0.01; r=0.76 P<0.05; respectively). CONCLUSION: Niacin can up-regulate LXRalpha and PPARgamma mRNA expression and promote the HDL-induced cholesterol efflux in adipocytes from hypercholesterolemic rabbits.
BACKGROUND: Adipose tissue contains a large amount of cholesterol and performs a buffer function for circulating cholesterol. Liver X receptors (LXR) alpha and peroxisome proliferator-activated receptor gamma (PPARgamma) might play a significant role in adipocyte cholesterol metabolism through mediation of cholesterol efflux. The aim of this study was to evaluate the effect of niacin on LXRalpha and PPARgamma expression and HDL-induced cholesterol efflux in adipocytes from hypercholesterolemic rabbits. METHODS: Twelve rabbits fed with high-cholesterol diet for 8 weeks were randomly divided into two groups: (1) high cholesterol group (n=6): maintained high cholesterol diet for 6 weeks; (2) niacin group (n=6): the same cholesterol diet plus niacin (200 mg/kg/d) for 6 weeks. Control group (n=6) was fed with normal diet for 14 weeks. Subcutaneous adipose was collected for adipocyte culture. Reverse transcription polymerase chain reaction (RT-PCR) was used to evaluate adipocytes LXRalpha mRNA expressions. Cholesterol efflux rate was determined through measuring release of radioactivity from (3)H-cholesterol prelabeled cells into medium containing high-density lipoprotein (HDL). The direct effect of niacin on LXRalpha and PPARgamma mRNA expression in primary rabbit adipocytes was assayed. RESULTS: High cholesterol diet resulted in decreased LXRalpha mRNA expressions and reduced HDL-induced cholesterol efflux rate in adipocytes. Six weeks of niacin treatment significantly enhanced the cholesterol efflux from adipocytes, which was related to the increased mRNA expressions of LXRalpha (r=0.71, P<0.05). In in vitro study, niacin dose-dependently stimulated LXRalpha and PPARgamma mRNA expression in cultured adipocytes. And various doses of niacin-induced cholesterol efflux was positive correlation with LXRalpha and PPARgamma mRNA expression (r=0.83 P<0.01; r=0.76 P<0.05; respectively). CONCLUSION:Niacin can up-regulate LXRalpha and PPARgamma mRNA expression and promote the HDL-induced cholesterol efflux in adipocytes from hypercholesterolemic rabbits.
Authors: Eduardo Nicolas Pollono; Maria A Lopez-Olivo; Juan Antonio Martinez Lopez; Maria E Suarez-Almazor Journal: Clin Rheumatol Date: 2010-04-10 Impact factor: 2.980
Authors: Tingjing Ke; Rajkumar Dorajoo; Yi Han; Chiea-Chuen Khor; Rob M van Dam; Jian-Min Yuan; Woon-Puay Koh; Jianjun Liu; Yik Ying Teo; Daniel Y T Goh; E Shyong Tai; Tien Yin Wong; Ching-Yu Cheng; Yechiel Friedlander; Chew-Kiat Heng Journal: Ann Hum Genet Date: 2016-09 Impact factor: 1.670