The role of lipid droplets in the steroid hormone synthesis in MLTC-1 mouse Leydig tumor cells.

脂滴是参与多种细胞内过程的功能亚细胞器。尽管LD存在于几乎所有类型的真核细胞中，但其性质在不同组织中差异很大。类固醇生成细胞通常会积聚大量小的胞浆LDs，但LD相关蛋白的分布及其生物学意义尚不清楚。我发现小鼠间质肿瘤细胞(MLTC-1)的LD组分中含有丰富的类固醇合成酶，特别是3β-HSD1和17β-HSD11，黄体生成素(LH)激活类固醇生成后，LDS的形态发生了剧烈的变化。在刺激下，核周LDs转变为相对新生的LDs，并可能与内质网融合。我接着研究了HL-60来源的中性粒细胞的LDS，发现Perilipin-3(PLIN3)在LD的生物发生中起着关键作用，并且PLIN3与PGE2的合成和分泌有关。

Lipid droplets (LDs) are functional subcellular organelles involved in multiple intracellular processes. Although LDs are found in nearly all types of eukaryotic cells, their properties are highly variable among tissues.Steroidogenic cells normally accumulate numerous small cytosolic LDs, but the profiles of LD-associated proteins and the biological significance of these remains unclear. I found that LD fraction from mouse leydig tumor (MLTC-1) cells, abundantly contains the enzymes for steroidogenesis, especially 3beta-HSD1 and 17beta-HSD11 and the activation of steroidgenesis by luteinizing hormone (LH) caused drastic change in morphology of LDs. Upon stimulation, perinuclear LDs are changed into relatively nascent LDs and possibly fused to ER. I next studied about the LDs of HL-60-derived neutrophils and found that perilipin-3 (PLIN3) has a pivotal role in LD-biogenesis, and that PLIN3 is associated with the synthesis and secretion of PGE2.