title: Milk Fat Globule-EGF Factor 8, Secreted by Mesenchymal Stem Cells, Protects Against Liver Fibrosis in Mice.
abstract: Mesenchymal stem cells (MSCs) mediate tissue repair and might be used to prevent or reduce liver fibrosis. However, little is known about the anti-fibrotic factors secreted from MSCs or their mechanisms.
  
  
  
  Umbilical cord-derived MSCs (UCMSCs) were differentiated into hepatocyte-like cells (hpUCMSCs), medium was collected, and secretome proteins were identified and quantified using nanochip-liquid chromatography/quadrupole time-of-flight mass spectrometry. Liver fibrosis was induced in mice by intraperitoneal injection of thioacetamide or CCl4; some mice were then given injections of secretomes or proteins. Liver tissues were collected and analyzed by histology or polymerase chain reaction array to analyze changes in gene expression patterns. We analyzed the effects of MSC secretomes and potential anti-fibrotic proteins on transforming growth factor β 1 (TGFβ1)-mediated activation of human hepatic stellate cell (HSC) lines (hTert-HSC and LX2) and human primary HSCs. Liver tissues were collected from 16 patients with liver cirrhosis and 16 individuals without cirrhosis (controls) in Korea and analyzed by immunohistochemistry and immunoblots.
  
  
  
  In mice with fibrosis, accumulation of extracellular matrix proteins was significantly reduced 3 days after injecting secretomes from UCMSCs, and to a greater extent from hpUCMSCs; numbers of activated HSCs that expressed the myogenic marker α-smooth muscle actin (α-SMA, encoded by ACTA2 [actin, alpha 2, smooth muscle]) were also reduced. Secretomes from UCMSCs, and to a greater extent from hpUCMSCs, reduced liver expression of multiple fibrotic factors, collagens, metalloproteinases, TGFβ, and Smad proteins in the TGFβ signaling pathways. In HSC cell lines and primary HSCs, TGFβ1-stimulated upregulation of α-SMA was significantly inhibited (and SMAD2 phosphorylation reduced) by secretomes from UCMSCs, and to a greater extent from hpUCMSCs. We identified 32 proteins in secretomes of UCMSCs that were more highly concentrated in secretomes from hpUCMSCs and inhibited TGFβ-mediated activation of HSCs. One of these, milk fat globule-EGF factor 8 (MFGE8), was a strong inhibitor of activation of human primary HSCs. We found MFGE8 to down-regulate expression of TGFβ type I receptor by binding to αvβ3integrin on HSCs and to be secreted by MSCs from umbilical cord, teeth, and bone marrow. In mice, injection of recombinant human MFGE8 had anti-fibrotic effects comparable to those of the hpUCMSC secretome, reducing extracellular matrix deposition and HSC activation. Co-injection of an antibody against MFGE8 reduced the anti-fibrotic effects of the hpUCMSC secretome in mice. Levels of MFGE8 were reduced in cirrhotic liver tissue from patients compared with controls.
  
  
  
  MFGE8 is an anti-fibrotic protein in MSC secretomes that strongly inhibits TGFβ signaling and reduces extracellular matrix deposition and liver fibrosis in mice.
authors.affiliation: Laboratory of Stem Cells and Tissue Regeneration, Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea.
authors.forename: Su Yeon
authors.initials: SY
authors.lastname: An
authors.affiliation: Laboratory of Stem Cells and Tissue Regeneration, Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea.
authors.forename: Yu Jin
authors.initials: YJ
authors.lastname: Jang
authors.affiliation: Laboratory of Stem Cells and Tissue Regeneration, Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea.
authors.forename: Hee-Joung
authors.initials: HJ
authors.lastname: Lim
authors.affiliation: Laboratory of Stem Cells and Tissue Regeneration, Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea.
authors.forename: Jiyou
authors.initials: J
authors.lastname: Han
authors.affiliation: Laboratory of Stem Cells and Tissue Regeneration, Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea.
authors.forename: Jaehun
authors.initials: J
authors.lastname: Lee
authors.affiliation: Laboratory of Stem Cells and Tissue Regeneration, Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea.
authors.forename: Gyunggyu
authors.initials: G
authors.lastname: Lee
authors.affiliation: Laboratory of Stem Cells and Tissue Regeneration, Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea.
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Park
authors.affiliation: Laboratory of Stem Cells and Tissue Regeneration, Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea.
authors.forename: Seo-Young
authors.initials: SY
authors.lastname: Park
authors.affiliation: Biotechnology Research Institute, HurimBioCell Inc., Seoul, Republic of Korea.
authors.forename: Ji Hyang
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Biotechnology Research Institute, HurimBioCell Inc., Seoul, Republic of Korea.
authors.forename: Byung-Rok
authors.initials: BR
authors.lastname: Do
authors.affiliation: Department of Oral Medicine and Oral Diagnosis, Seoul National University Dental Hospital, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea; Nexel, Co., Ltd, Seoul, Republic of Korea.
authors.forename: Choongseong
authors.initials: C
authors.lastname: Han
authors.affiliation: Department of Oral Medicine and Oral Diagnosis, Seoul National University Dental Hospital, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
authors.forename: Hee-Kyung
authors.initials: HK
authors.lastname: Park
authors.affiliation: Department of Surgery, Daejeon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Daejeon, Republic of Korea.
authors.forename: Ok-Hee
authors.initials: OH
authors.lastname: Kim
authors.affiliation: Division of Hepatology, Department of Internal Medicine, Daejeon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Daejeon, Republic of Korea.
authors.forename: Myeong Jun
authors.initials: MJ
authors.lastname: Song
authors.affiliation: Department of Surgery, Daejeon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Daejeon, Republic of Korea.
authors.forename: Say-June
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Laboratory of Stem Cells and Tissue Regeneration, Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea. Electronic address: jhkim@korea.ac.kr.
authors.forename: Jong-Hoon
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism*; D002251:Carbon Tetrachloride / Q000633:toxicity; D002460:Cell Line; D003094:Collagen / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D055166:Hepatic Stellate Cells; D022781:Hepatocytes; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D008103:Liver Cirrhosis / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D008297:Male; D059630:Mesenchymal Stem Cells / Q000378:metabolism; D055442:Metabolome; D045726:Metalloproteases / Q000378:metabolism; D051379:Mice; D008894:Milk Proteins / Q000378:metabolism*; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D051899:Smad2 Protein / Q000378:metabolism; D013853:Thioacetamide / Q000633:toxicity; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
chemical_list: D000954:Antigens, Surface; D039302:Integrin alphaVbeta3; C098942:MFGE8 protein, human; C490919:Mfge8 protein, mouse; D008894:Milk Proteins; D018125:Receptors, Transforming Growth Factor beta; D051899:Smad2 Protein; C508960:TGFB1 protein, human; C508961:Tgfb1 protein, mouse; D053773:Transforming Growth Factor beta1; D013853:Thioacetamide; D003094:Collagen; D002251:Carbon Tetrachloride; D045726:Metalloproteases
keywords: Decorin; MMP; Mouse Model; Signal Transduction