Fuzhuan Brick Tea Regulates Sterol Regulatory Element-binding Proteins To Achieve Lipid Metabolism In Caenorhaditis Elegans With The Different Concentrations Of Cholesterol

Tea can inhibit fatty acid desaturation.Polyunsaturated fatty acids can reduce the levels of chelosterol in vivo.However,the modulating effects of tea on cholesterol metabolism remains unknown.Unlike mammalian,C.elegans has been identified to have the homologues fat metabolism pathway and lack several components of the de novo sterol biosynthetic pathway,which makes it an excellent animal model organism to study the metabolism of lipid and cholesterol.To explore the Fuzhuan brick tea(FBTE)function on regulating fat storage,it was used to investigate fat accumulation,reproduction,growth and gene expression related to lipid and cholesterol metabolism under the different concentrations of cholesterol nutrient medium and the administration of the extract of FBTE during the larval stage.The main results are summarized as follows:(1)FBTE reduced fat storage in Caenorhaditis elegans in normal level of cholesterol.While it increased the fat accumulation of elegans in high level.The fat-degrade effect of the FBTE was inhibited under the cholesterol-free condition.(2)Under high-cholesterol condition,Caenorhabditis elegans had an increased fertility and fat storage of first filial generation.FBTE inhibited the transportation of somatic lipids to the germline,which might lead to a reduction of fecundity.However,it had no effect on the fat storage of F1.Under cholesterol-free condition,FBTE increased the transportation of somatic lipids to the germline and the reproduction and the fat storage of F1.(3)The body strokes analysis suggested that the movement of C.elegans could be recovered with cholesterol-rich diets by the FBTE.(4)The analysis of gene expression suggested that the FBTE suppressed the expression of genes involved in fatty acid synthesis(sbp-1,mdt-15,nhr-80,scd-1),and upregulated the expression of genes involved in fat oxidation(nht-49,aco-1)in Caenorhaditis elegans in normal level of cholesterol,thereby reduced the fat storage.FBTE increased the expression of genes involved in fatty acid synthesis(sbp-1,mdt-15,nhr-80,scd-1)and oxidation(nht-49,aco-1)with high cholesterol diet.Also FBTE promoted metabolism of fat and fatty acid synthesis,and further induced key enzymes that converted fatty acid and sterol to cholesteryl ester,and finally moderated cholesterol toxicity.The regulation of gene expression related to lipid and cholesterol metabolism of the FBTE was inhibited under cholesterol depletion conditions.The results showed that the modulation of fat storage of elegans by FBTE was cholesterol dependent.The homeostatic balance of lipid storage between the somatic and germ cells was mediated by FBTE in worms under cholesterol depletion or high-cholesterol environments.