Haridoss Srividyameena, Yovchev Mladen I, Schweizer Hannah, Megherhi Sabreen, Beecher Maria, Locker Joseph, Oertel Michael
Department of Pathology University of Pittsburgh Pittsburgh PA.
Pittsburgh Liver Research Center University of Pittsburgh Pittsburgh PA.
Hepatol Commun. 2017 Nov 3;1(9):852-870. doi: 10.1002/hep4.1106. eCollection 2017 Nov.
Activin A, a multifunctional cytokine, plays an important role in hepatocyte growth suppression and is involved in liver size control. The present study was aimed to determine the cell location of activin A in the normal rat liver microenvironment and the contribution of activin A signaling to the hepatocyte phenotype to obtain insight into molecular mechanisms. Immunohistochemical and hybridization analyses identified hepatocytes as the major activin A-positive cell population in normal liver and identified mast cells as an additional activin A source. To investigate paracrine and autocrine activin A-stimulated effects, hepatocytes were cocultured with engineered activin A-secreting cell lines (RF1, TL8) or transduced with an adeno-associated virus vector encoding activin βA, which led to strikingly altered expression of cell cycle-related genes (Ki-67, E2F transcription factor 1 [], minichromosome maintenance complex component 2 [], forkhead box M1 []) and senescence-related genes (cyclin-dependent kinase inhibitor 2B [p15/], differentiated embryo-chondrocyte expressed gene 1 []) and reduced proliferation and induction of senescence. Microarray analyses identified 453 differentially expressed genes, many of which were not yet recognized as activin A downstream targets (e.g., ADAM metallopeptidase domain 12 [], semaphorin 7A [], LIM and cysteine-rich domains-1 [], DAB2, clathrin adaptor protein []). Among the main activin A-mediated molecular/cellular functions are cellular growth/proliferation and movement, molecular transport, and metabolic processes containing highly down-regulated genes, such as cytochrome P450, subfamily 2, polypeptide 11 (), sulfotransferase family 1A, member 1 (), glycine-N-acyltransferase (), and bile acid-CoA:amino acid N-acyltransferase (). Moreover, Ingenuity Pathway Analyses identified particular gene networks regulated by hepatocyte nuclear factor (HNF)-4α and peroxisome proliferator-activated receptor gamma (PPARγ) as key targets of activin A signaling. : Our models demonstrated that activin A-stimulated growth inhibition and cellular senescence is mediated through p15/ and is associated with up- and down-regulation of numerous target genes involved in multiple biological processes performed by hepatocytes, suggesting that activin A fulfills a critical role in normal liver function. ( 2017;1:852-870).
激活素A是一种多功能细胞因子，在抑制肝细胞生长中起重要作用，并参与肝脏大小的调控。本研究旨在确定激活素A在正常大鼠肝脏微环境中的细胞定位以及激活素A信号传导对肝细胞表型的影响，以深入了解其分子机制。免疫组织化学和杂交分析确定肝细胞是正常肝脏中主要的激活素A阳性细胞群体，并确定肥大细胞是激活素A的另一个来源。为了研究旁分泌和自分泌激活素A刺激的效应，将肝细胞与工程化的激活素A分泌细胞系（RF1、TL8）共培养，或用编码激活素βA的腺相关病毒载体进行转导，这导致细胞周期相关基因（Ki-67、E2F转录因子1、微小染色体维持复合物组分2、叉头框M1）和衰老相关基因（细胞周期蛋白依赖性激酶抑制剂2B、分化胚胎软骨细胞表达基因1）的表达发生显著改变，并降低了增殖和诱导了衰老。微阵列分析鉴定出453个差异表达基因，其中许多尚未被认为是激活素A的下游靶点（例如，ADAM金属蛋白酶结构域12、信号素7A、富含LIM和半胱氨酸结构域-1、DAB2、网格蛋白衔接蛋白）。激活素A介导的主要分子/细胞功能包括细胞生长/增殖和运动、分子运输以及代谢过程，其中包含高度下调的基因，如细胞色素P450 2家族多肽11、磺基转移酶家族1A成员1、甘氨酸-N-酰基转移酶和胆汁酸-CoA：氨基酸N-酰基转移酶。此外， Ingenuity通路分析确定由肝细胞核因子（HNF）-4α和过氧化物酶体增殖物激活受体γ（PPARγ）调节的特定基因网络是激活素A信号传导的关键靶点。我们的模型表明，激活素A刺激的生长抑制和细胞衰老通过p15/介导，并与肝细胞执行的多个生物学过程中涉及的众多靶基因的上调和下调相关，这表明激活素A在正常肝功能中起关键作用。（2017；1：852 - 870）
