藥物 YC-1 對於 RAW 264.7 巨噬細胞內脂肪滴堆積現象具有抑制作用並且可以誘發脂質分解   全文下載

YC-1 Inhibits Lipid Droplet Accumulation and Induces Lipolysis in Lipid-Laden RAW264.7 Macrophages

巨噬細胞變成泡狀細胞（foam cell）在動脈粥狀硬化的初期與發展過程中，扮演很重要的角色。本篇研究探討在巨噬細胞轉變成泡狀細胞時，藥物YC-1（一種合成的benzylindazole化合物）對於細胞內脂質代謝的影響。我們採用RAW 264.7巨噬細胞株為材料，藉由加入油酸或是加入氯化鈷於培養液中，誘發泡狀細胞的形成，型態上可以觀察到RAW 264.7巨噬細胞株內，出現許多Nile red染色的脂肪小滴。以藥物YC-1進行前處理，可以抑制油酸誘導的脂肪滴堆積現象。如果藥物YC-1與油酸共同加入處理，經由檢測脂肪滴表面積的大小，也發現具有減弱脂肪滴形成的現象。如果當巨噬細胞已經堆積許多脂肪滴，再加入藥物YC-1處理，則會出現脂質分解現象，並且與藥物作用時間以及作用濃度呈正相關性。此外，以soluble guanynyl cyclase（sGC）的抑制劑ODQ處理，無法阻斷YC-1的作用效果。另外一種sGC的活化劑BAY 41-2272，以及dibytyryl cGMP兩者會增加細胞內cGMP濃度的藥物，皆無法產生與YC-1相同的作用效果。藥物YC-1處理，不會影響巨噬細胞內sGC的活性，細胞內cGMP的含量也沒有顯著上升。此外，藥物YC-1處理，可以有效減少氯化鈷所誘發的脂肪滴堆積情形。上述這些結果顯示，藥物YC-1在RAW 264.7巨噬細胞株內對於脂質代謝的作用，可能不是經由sGC/cGMP的相關途徑，達到抑制脂肪滴堆積的作用。我們的結果發現藥物 YC-1具有調節巨噬細胞內的脂質代謝功能，並且可以有效降低泡狀細胞的形成，或許將來可以應用於預防或是治療動脈狀硬化相關的疾病。

Macrophage foam cells play a central role in the initiation and progression of atherosclerosis. The present study investigates the effect of YC-1, a synthetic benzylindazole compound, on lipid metabolism in macrophage-derived foam cells. Foam cell formation was induced by incubating cultured RAW264.7 macrophages with oleic acid (OA) or cobalt chloride (CoCl2) (a hypoxia mimetic). Morphological observation showed several Nile red-positive lipid droplets in the cytoplasm of OA-treated RAW264.7 macrophages. Pretreatment with 60 μM YC-1 could inhibit lipid accumulation. Co-incubation with OA and YC-1 also attenuated lipid accumulation due to the decrease in surface area of lipid droplets. Post-treatment with YC-1 induced lipolysis and free fatty acid release in lipid-laden macrophages in both dose- and time-dependent manners. In addition, ODQ, a soluble guanynyl cyclase (sGC) inhibitor, could not reverse the inhibitory effect of YC-1 on lipid accumulation, or block the lipolytic effect of YC-1 in lipid-laden macrophages. Neither another nitric oxide-independent sGC activator (BAY 41-2272) nor dibutyryl cGMP (db-cGMP) could mimic the effects of YC-1. Both intracellular sGC activity and the cGMP level remained unchanged following YC-1 incubation. These results suggested that the mechanism of YC-1-mediated lipid metabolism was via an sGC/cGMP-independent signal transduction pathway in RAW264.7 macrophages. In addition, YC-1 significantly attenuated CoCl2-induced lipid droplets accumulation. Our results demonstrated that YC-1 could mediate lipid metabolism in macro-phage and reduce foam cell formation, and it could be regarded as a potential drug for the prevention or therapy of atherosclerosis.