title: Thy-1 is expressed in hepatic myofibroblasts and not oval cells in stem cell-mediated liver regeneration.
abstract: Thy-1, a marker of hematopoietic stem cells, has been reported to be expressed by oval cells proliferating during stem cell-mediated regeneration in rat liver, suggesting a relationship between the two cell populations. Consequently, Thy-1 has become an accepted cell surface marker to sort hepatic oval cells. In the present study we used the well-characterized 2-acetylaminfluorene/partial hepatectomy model to induce transit-amplification of hepatic oval cells in the regenerating liver and characterized Thy-1 expression using Northern hybridization, quantitative reverse transcriptase-polymerase chain reaction analysis, immunofluorescence confocal microscopy, and immunoelectronmicroscopy. We found that Thy-1 expression was induced during transit-amplification of the oval cell population, but Thy-1 mRNA was not present in the alpha-fetoprotein-expressing oval cells. Thy-1 protein was consistently present outside the basement membrane surrounding the oval cells. It overlapped frequently with smooth muscle actin staining. A similar cellular localization of the Thy-1 protein was found on human liver specimens with ductular reactions obtained from patients with fulminant liver failure. Furthermore, Thy-1 was expressed by myofibroblasts in experimental liver fibrosis models without oval cell proliferation. We conclude that Thy-1 is not a marker of oval cells but is present on a subpopulation of myofibroblasts/stellate cells.
authors: First Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary.
authors: Katalin
authors: K
authors: Dezso
authors: Peter
authors: P
authors: Jelnes
authors: Viktória
authors: V
authors: László
authors: Kornélia
authors: K
authors: Baghy
authors: Csaba
authors: C
authors: Bödör
authors: Sándor
authors: S
authors: Paku
authors: Niels
authors: N
authors: Tygstrup
authors: Hanne Cathrine
authors: HC
authors: Bisgaard
authors: Peter
authors: P
authors: Nagy
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D049109:Cell Proliferation; D005347:Fibroblasts / Q000378:metabolism* / Q000473:pathology; D022781:Hepatocytes / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008099:Liver / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D008106:Liver Cirrhosis, Experimental / Q000378:metabolism / Q000473:pathology; D017114:Liver Failure, Acute / Q000378:metabolism / Q000473:pathology; D008115:Liver Regeneration; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D013234:Stem Cells / Q000502:physiology*; D018800:Thy-1 Antigens / Q000096:biosynthesis*
chemical_list: D018800:Thy-1 Antigens