Soluble factors derived from human amniotic epithelial cells suppress collagen production in human hepatic stellate cells ALEXANDER HODGE 1,4 , DINUSHKA LOURENSZ 1,4 , VIJESH VAGHJIANI 2 , HUYEN NGUYEN 1,4 , JORGE TCHONGUE 1,4 , BO WANG 5 , PADMA MURTHI 3 , WILLIAM SIEVERT 1,4 & URSULA MANUELPILLAI 2 1 Centre for Inflammatory Diseases, Monash University, Melbourne, Australia, 2 Centre for Genetic Diseases, Monash Institute of Medical Research, Monash University, Melbourne, Australia, 3 Department of Obstetrics & Gynaecology, University of Melbourne & Pregnancy Research Centre, Department of Perinatal Medicine, Royal Women’s Hospital, Melbourne, Australia, 4 Gastroenterology and Hepatology Unit, Monash Health, Melbourne, Australia, and 5 Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia Abstract Background. Intravenous infusion of human amniotic epithelial cells (hAECs) has been shown to ameliorate hepatic fibrosis in murine models. Hepatic stellate cells (HSCs) are the principal collagen-secreting cells in the liver. The aim of this study was to investigate whether factors secreted by hAECs and present in hAEC-conditioned medium (CM) have anti-fibrotic effects on activated human HSCs. Methods. Human AECs were isolated from the placenta and cultured. Human hepatic stellate cells were exposed to hAEC CM to determine potential anti-fibrotic effects. Results. HSCs treated for 48 h with hAEC CM displayed a significant reduction in the expression of the myofibroblast markers a-smooth muscle actin and platelet-derived growth factor. Expression of the pro-fibrotic cytokine transforming growth factor-b1 (TGF-b1) and intra- cellular collagen were reduced by 45% and 46%, respectively. Human AEC CM induced HSC apoptosis in 11.8% of treated cells and reduced HSC proliferation. Soluble human leukocyte antigeneG1, a hAEC-derived factor, significantly decreased TGF-b1 and collagen production in activated HSCs, although the effect on collagen production was less than that of hAEC CM. The reduction in collagen and TGF-B1 could not be attributed to PGE2, relaxin, IL-10, TGF-B3, FasL or TRAIL. Conclusions. Human AEC CM treatment suppresses markers of activation, proliferation and fibrosis in human HSCs as well as inducing apoptosis and reducing proliferation. Human AEC CM treatment may be effective in ameliorating liver fibrosis and warrants further study. Key Words: amnion epithelial cells, hepatic stellate cells, liver cirrhosis, placental stem cells Introduction Liver fibrosis represents a wound-healing response to chronic inflammation leading to the accumulation of collagen and other extracellular matrix (ECM) pro- teins that can result in distortion of liver architecture and vasculature, liver dysfunction and hepatocyte dysplasia. Inflammatory liver injury can be precipitated by viral, metabolic, toxin, autoimmune and other causes. The hepatic stellate cell (HSC) is the resident liver cell at the center of collagen deposition because its response to tissue injury initiates and modulates liver fibrosis. HSC activation represents a series of cellular processes resulting in transformation to a myofibro- blast-like, pro-fibrotic phenotype. The driving forces leading to this transformation are hepatocyte apoptosis (1) and resident and recruited immune cells, which are sources of cytokines such as platelet-derived growth factor-b (PDGFb), endothelin-1, connective tissue growth factor, epidermal growth factor and trans- forming growth factor-b (TGF-b) (2). This pro- fibrotic response results in ECM deposition and liver fibrosis (3). If the stimulus for liver injury is removed, activated HSCs may revert to a quiescent phenotype or decrease in number through spontaneous or directed apoptosis (4). The remaining HSCs express a number of enzymes and enzyme inhibitors whose net result is fibrolysis or ECM degradation leading to regression of liver fibrosis. If liver injury is perpetuated, the ongoing fibrogenesis can lead to cirrhosis and its associated complications. Correspondence: Ursula Manuelpillai, PhD, Monash Institute of Medical Research, 27e31 Wright Street, Clayton, Victoria 3168, Australia. E-mail: ursula. manuelpillai@monash.edu Cytotherapy, 2014; 0: 1e13 (Received 1 July 2013; accepted 5 January 2014) ISSN 1465-3249 Copyright Ó 2014, International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jcyt.2014.01.005