Tricyclic Antidepressants Promote Ceramide Accumulation to Regulate Collagen Production in Human Hepatic Stellate Cells.
Tricyclic Antidepressants Promote Ceramide Accumulation to Regulate Collagen Production in Human Hepatic Stellate Cells.
复制标题
DOI：
10.1038/srep44867
复制
发表时间：
2017-03-21
影响因子：
4.6
通讯作者：
Mullen AC
中科院分区：
文献类型：
--
作者：
Chen JY;Newcomb B;Zhou C;Pondick JV;Ghoshal S;York SR;Motola DL;Coant N;Yi JK;Mao C;Tanabe KK;Bronova I;Berdyshev EV;Fuchs BC;Hannun Y;Chung RT;Mullen AC
肝星状细胞(HSCs)损伤后的激活是肝纤维化的关键步骤，其特征是静止的HSCs转分化为HSC肌成纤维细胞，后者分泌细胞外基质蛋白导致纤维瘢痕形成。目前还没有直接抑制肝纤维化的治疗方法。我们开发了一种小分子筛选器，通过对脂滴的定量来鉴定使人HSC肌成纤维细胞失活的化合物。我们筛选了1600个化合物，确定了21个诱导HSC失活的小分子。四种HIT为三环类抗抑郁药(TCA)，它们抑制HSC中促纤维化因子α-肌动蛋白-2(ACTA2)和α-I型胶原(COL1A1)的表达。RNA测序表明鞘脂通路是TCAs的靶标。事实上，TCA处理HSCs通过抑制酸性神经酰胺酶(ACDase)促进了神经酰胺的积累。ACDase的缺失也促进了神经酰胺的积累，并与COL1A1表达降低有关。用aCDase抑制剂B13处理，就像外源性神经酰胺一样，重现了抗纤维化表型。我们的结果表明，对脂滴的检测为筛选肝纤维化调节剂提供了一个可靠的读数，并确定了神经酰胺的新的抗纤维化作用。
Activation of hepatic stellate cells (HSCs) in response to injury is a key step in hepatic fibrosis, and is characterized by trans-differentiation of quiescent HSCs to HSC myofibroblasts, which secrete extracellular matrix proteins responsible for the fibrotic scar. There are currently no therapies to directly inhibit hepatic fibrosis. We developed a small molecule screen to identify compounds that inactivate human HSC myofibroblasts through the quantification of lipid droplets. We screened 1600 compounds and identified 21 small molecules that induce HSC inactivation. Four hits were tricyclic antidepressants (TCAs), and they repressed expression of pro-fibrotic factors Alpha-Actin-2 (ACTA2) and Alpha-1 Type I Collagen (COL1A1) in HSCs. RNA sequencing implicated the sphingolipid pathway as a target of the TCAs. Indeed, TCA treatment of HSCs promoted accumulation of ceramide through inhibition of acid ceramidase (aCDase). Depletion of aCDase also promoted accumulation of ceramide and was associated with reduced COL1A1 expression. Treatment with B13, an inhibitor of aCDase, reproduced the antifibrotic phenotype as did the addition of exogenous ceramide. Our results show that detection of lipid droplets provides a robust readout to screen for regulators of hepatic fibrosis and have identified a novel antifibrotic role for ceramide.