Discovery and Targeting of the Signaling Controls of PNPLA3 to Effectively Reduce Transcription, Expression, and Function in Pre-Clinical NAFLD/NASH Settings.
Discovery and Targeting of the Signaling Controls of PNPLA3 to Effectively Reduce Transcription, Expression, and Function in Pre-Clinical NAFLD/NASH Settings.
复制标题
DOI：
10.3390/cells9102247
复制
发表时间：
2020-10-07
期刊：
影响因子：
6
通讯作者：
Pingitore P
中科院分区：
文献类型：
--
作者：
Schwartz BE;Rajagopal V;Smith C;Cohick E;Whissell G;Gamboa M;Pai R;Sigova A;Grossman I;Bumcrot D;Sasidharan K;Romeo S;Sehgal A;Pingitore P
非酒精性脂肪性肝病(NAFLD)和非酒精性脂肪性肝炎(NASH)是新出现的世界性流行病，预计将成为肝脏移植的主要原因。NAFLD/NASH易感性和进展的最大遗传危险因素是包含Patatin样磷脂酶结构域3基因(PNPLA3)的单核苷酸多态性(SNP)，编码错义突变I148M的rs738409。这种氨基酸替代干扰了肝细胞中脂滴的正常重塑。它还被认为通过抑制肝星状细胞释放视黄醇而在促进肝纤维化方面发挥关键作用。根据人类人群中的基因剂量分析，以及PNPLA3中另一个自然产生的SNP(Rs2294918)的保护作用，降低148M纯合子个体的PNPLA3水平可能是治疗整个NAFLD谱的有效方法，当PNPLA3基因共同遗传时，PNPLA3的mRNA水平降低到50%，并抵消疾病风险。通过筛选针对原代人类肝细胞中活跃的特定信号通路的临床化合物文库，我们发现莫美洛替尼是一种在临床试验中被评估的治疗骨髓纤维化的药物，在所有基因型中都能有效下调PNPLA3的表达。我们发现莫美洛替尼治疗使人原代肝细胞和星状细胞中的PNPLA3mRNA减少了80%，并且通过对WT小鼠的急性和慢性治疗，在体内也是如此。使用PNPLA3突变蛋白的Nash纯合子的人类多系3D球体模型，我们还表明它降低了PNPLA3mRNA和细胞内脂质含量。此外，我们还表明，对PNPLA3的影响与PNPLA3基因调节区内染色质可及性的变化一致，与转录水平上的抑制一致。除了其主要报道的靶点JAK激酶外，莫洛替尼还抑制几种非JAK激酶，包括ACVR1。利用靶向siRNA敲除和信号通路扰动的组合，我们证明莫洛替尼主要通过抑制BMP信号而不是JAK/STAT途径来降低PNPLA3基因的表达。总体而言，我们的工作确定莫美洛替尼是一种潜在的NASH治疗药物，并发现了以前未发现的信号通路和PNPLA3之间的联系。这些途径可能被药物利用来“调节”基因表达水平，因此为NAFLD/NASH患者的高危亚群提供了潜在的治疗益处。
Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are emerging worldwide epidemics, projected to become the leading cause of liver transplants. The strongest genetic risk factor for NAFLD/NASH susceptibility and progression is a single-nucleotide polymorphism (SNP) in the patatin-like phospholipase domain-containing 3 gene (PNPLA3), rs738409, encoding the missense mutation I148M. This aminoacidic substitution interferes with the normal remodeling of lipid droplets in hepatocytes. It is also thought to play a key role in promoting liver fibrosis by inhibiting the release of retinol from hepatic stellate cells. Reducing PNPLA3 levels in individuals homozygous for 148M may be an effective treatment for the entire spectrum of NAFLD, based on gene dosage analysis in the human population, as well as the protective effect of another naturally occurring SNP (rs2294918) in PNPLA3 which, when co-inherited, reduces PNPLA3 mRNA levels to 50% and counteracts disease risk. By screening a clinical compound library targeting specific signaling pathways active in primary human hepatocytes, we identified momelotinib, a drug evaluated in clinical trials to treat myelofibrosis, as a potent down-regulator of PNPLA3 expression, across all genotypes. We found that momelotinib treatment yielded >80% reduction in PNPLA3 mRNA in human primary hepatocytes and stellate cells, as well as in vivo via acute and chronic treatment of WT mice. Using a human multilineage 3D spheroid model of NASH homozygous for the PNPLA3 mutant protein, we additionally show that it decreases PNPLA3 mRNA as well as intracellular lipid content. Furthermore, we show that the effects on PNPLA3 coincide with changes in chromatin accessibility within regulatory regions of the PNPLA3 locus, consistent with inhibition occurring at the level of transcription. In addition to its primary reported targets, the JAK kinases, momelotinib inhibits several non-JAK kinases, including ACVR1. Using a combination of targeted siRNA knockdowns and signaling pathway perturbations, we show that momelotinib reduces the expression of the PNPLA3 gene largely through the inhibition of BMP signaling rather than the JAK/STAT pathway. Overall, our work identified momelotinib as a potential NASH therapeutic and uncovered previously unrecognized connections between signaling pathways and PNPLA3. These pathways may be exploited by drug modalities to “tune down” the level of gene expression, and therefore offer a potential therapeutic benefit to a high at-risk subset of NAFLD/NASH patients.
登录
查看更多内容
影响因子：
13.5
作者：
Speliotes, Elizabeth K.;Butler, Johannah L.;Palmer, Cameron D.;Voight, Benjamin F.;Hirschhorn, Joel N.
通讯作者：
Hirschhorn, Joel N.
影响因子：
3.5
作者：
Pirazzi C;Valenti L;Motta BM;Pingitore P;Hedfalk K;Mancina RM;Burza MA;Indiveri C;Ferro Y;Montalcini T;Maglio C;Dongiovanni P;Fargion S;Rametta R;Pujia A;Andersson L;Ghosal S;Levin M;Wiklund O;Iacovino M;Borén J;Romeo S
通讯作者：
Romeo S
影响因子：
20.3
作者：
Asshoff, Malte;Petzer, Verena;Theurl, Igor
通讯作者：
Theurl, Igor
影响因子：
13.5
作者：
Bruschi, Francesca Virginia;Claudel, Thierry;Trauner, Michael
通讯作者：
Trauner, Michael
影响因子：
13.5
作者：
Rotman, Yaron;Koh, Christopher;Zmuda, Joseph M.;Kleiner, David E.;Liang, T. Jake
通讯作者：
Liang, T. Jake