Basic study for analysis and application of bio-factor which regulate transfer of cholresterol in vivo.

动脉壁动脉粥样硬化病变中常见的富含脂质的泡沫细胞被认为至少部分来自组织巨噬细胞，这些巨噬细胞已经被富含胆固醇酯的脂蛋白吞噬。组织巨噬细胞本身是从进入内膜下空间的循环血单核细胞衍生而来的。尽管亚单核细胞转化为泡沫细胞的机制尚不完全清楚，但清道夫受体途径是导致这些细胞中胆固醇酯积累的一个过程。抑制巨噬细胞中胆固醇酯积累的药物在阐明泡沫细胞形成的机制和开发防止动脉粥样硬化斑块形成的药物方面都是有用的。据报道，一系列抗真菌药物对细胞胆固醇代谢有实质性影响。在本研究中获得的数据de…更多的证据表明，抗菌药物之一酮康唑通过限制内吞胆固醇从溶酶体到其他细胞部位的运动而有效地抑制胆固醇酯的合成。此外，还评估了各种类固醇衍生物抑制巨噬细胞内吞胆固醇形成胆固醇酯的能力。在所测试的各种类固醇中，一组在C17或C20位具有氧基的类固醇，如孕烯醇酮、孕酮、雄烯二酮和脱氢异雄酮，在10微米时完全抑制胆固醇酯的形成。相反，另一类具有C17位羟基的类固醇如睾酮和雄烯二醇的作用较小，在100微米或更高的位置对胆固醇酯的形成完全抑制。对前一类类固醇的抑制作用机理进行了进一步研究。这些类固醇不会阻止脂质体的摄取或溶酶体的水解，也不会阻止脂肪酰链的酯化为三酰甘油。当与在C17或C20位置上具有氧基的类固醇孵化时。通过纤维蛋白胆固醇染色的细胞化学观察，巨噬细胞摄取的游离胆固醇很可能积聚在吞噬空泡中。这些结果表明，一系列结构相关的类固醇通过阻断细胞内内吞胆固醇从溶酶体到内质网的运输来抑制巨噬细胞中胆固醇酯的形成。较少

The lipid-laden foam cells that are typically found in atherosclerotic lesions in the arterial wall are believed to be derived, at least in part, from tissue macrophages that have become engorged with cholesteryl ester-rich lipoproteins. Tissue macrophages themselves are derived from circulating blood monocytes that have entered the subendotherial space. Although the mechanism for the conversion of a subendotherial monocyte to a foam cell is not fully understood, one process that has been proposed to contribute to the accumulation of cellular cholesteryl ester in these cells is the scavenger receptor pathway.The agents which inhibit cholesteryl ester accumulation in macrophages should be useful in both elucidating mechanism involved in foam cell formation and developing pharmacological drugs to prevent the formation of atherosclerotic plaques. A series of antimycotics were reported to have substantial effects on cellular cholesterol metabolism. The data obtained in the present study de … More monstrate that one of the antimycotics, ketoconazole, effectively inhibit cholesteryl ester synthsis by restricting the movement of endocytosed cholesterol from lysosomes to other cellular sites.In addition, various steroid derivertives were assessed for their ability to inhibit the cholesteryl ester formation from endocytosed cholesterol by macrophages. Among various steroids tested, one group of steroids having an oxo group at the C17 or C20 position such as pregnenolone, progesterone, androstenedione, and dehydroisoandrosterone completely inhibited cholesteryl ester formation at 10 muM.In contrast, other group of steroids having a hydroxy group at the C17 position such as testosterone and androstenediol had a lesser effect ; complete inhibition for cholesteryl ester formation was achieved at 100 muM or more. The mechanism for the inhibition by the former class of steroids was further studied. These steroids did not block the uptake or lysosomal hydrolysis of liposomes, nor esterification of fatty acyl chains into triacylglycerols. Upon incubation with the steroids having an oxo group at the C17 or C20 position. free cholesterol taken up by the macrophages is likely to be accumulated in phagocytotic vacuoles from cytochemical observation with filipin-cholesterol staining. These results indicate that a series of structurally-related steroids characterized by the presence of an oxo group at the C17 or C20 position inhibit cholesteryl ester formation in macrophages by blocking the intracellular transport of endocytosed cholesterol from lysosomes to endoplasmic reticulum. Less