title: Hematopoietic stem cells and liver regeneration: differentially acting hematopoietic stem cell mobilization agents reverse induced chronic liver injury.
abstract: Bone marrow (BM) could serve as a source of cells facilitating liver repopulation in case of hepatic damage. Currently available hematopoietic stem cell (HSC) mobilizing agents, were comparatively tested for healing potential in liver fibrosis. Carbon tetrachloride (CCl4)-injured mice previously reconstituted with Green Fluorescent Protein BM were mobilized with Granulocyte-Colony Stimulating Factor (G-CSF), Plerixafor or G-CSF+Plerixafor. Hepatic fibrosis, stellate cell activation and oval stem cell frequency were measured by Gomori and by immunohistochemistry for a-Smooth Muscle Actin and Cytokeratin-19, respectively. Angiogenesis was evaluated by ELISA and immunohistochemistry. Quantitative real-time PCR was used to determine the mRNA levels of liver Peroxisome Proliferator-Activated Receptor gamma (PPAR-γ), Interleukin-6 (IL-6) and Tumor Necrosis-alpha (TNFα). BM-derived cells were tracked by double immunofluorescence. The spontaneous migration of mobilized HSCs towards injured liver and its cytokine secretion profile was determined in transwell culture systems. Either single-agent mobilization or the combination of agents significantly ameliorated hepatic damage by decreasing fibrosis and restoring the abnormal vascular network in the liver of mobilized mice compared to CCl4-only mice. The degree of fibrosis reduction was similar among all mobilized mice despite that G-CSF+Plerixafor yielded significantly higher numbers of circulating HSCs over other agents. The liver homing potential of variously mobilized HSCs differed among the agents. An extended G-CSF treatment provided the highest anti-fibrotic effect over all tested modalities, induced by the proliferation of hepatic stem cells and decreased hepatic inflammation. Plerixafor-mobilized HSCs, despite their reduced liver homing potential, reversed fibrosis mainly by increasing hepatic PPAR-γ and VEGF expression. In all groups, BM-derived mature hepatocytes as well as liver-committed BM stem cells were detected only at low frequencies, further supporting the concept that alternative mechanisms rather than direct HSC effects regulate liver recovery. Overall, our data suggest that G-CSF, Plerixafor and G-CSF+Plerixafor act differentially during the wound healing process, ultimately providing a potent anti-fibrotic effect.
authors.affiliation: Gene and Cell Therapy Center, Hematology Department-BMT Unit, George Papanicolaou Hospital, Thessaloniki, Greece; Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Tsolaki
authors.affiliation: Gene and Cell Therapy Center, Hematology Department-BMT Unit, George Papanicolaou Hospital, Thessaloniki, Greece.
authors.forename: Evangelia
authors.initials: E
authors.lastname: Athanasiou
authors.affiliation: Gene and Cell Therapy Center, Hematology Department-BMT Unit, George Papanicolaou Hospital, Thessaloniki, Greece; Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Gounari
authors.affiliation: Gene and Cell Therapy Center, Hematology Department-BMT Unit, George Papanicolaou Hospital, Thessaloniki, Greece; Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Zogas
authors.affiliation: Gene and Cell Therapy Center, Hematology Department-BMT Unit, George Papanicolaou Hospital, Thessaloniki, Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Siotou
authors.affiliation: Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Minas
authors.initials: M
authors.lastname: Yiangou
authors.affiliation: Gene and Cell Therapy Center, Hematology Department-BMT Unit, George Papanicolaou Hospital, Thessaloniki, Greece.
authors.forename: Achilles
authors.initials: A
authors.lastname: Anagnostopoulos
authors.affiliation: Gene and Cell Therapy Center, Hematology Department-BMT Unit, George Papanicolaou Hospital, Thessaloniki, Greece. Electronic address: eyannaki@u.washington.edu.
authors.forename: Evangelia
authors.initials: E
authors.lastname: Yannaki
mesh_terms: D000818:Animals; D001596:Benzylamines; D015415:Biomarkers / Q000378:metabolism; D002251:Carbon Tetrachloride / Q000009:adverse effects; D056487:Chemical and Drug Induced Liver Injury, Chronic / Q000175:diagnosis / Q000378:metabolism / Q000401:mortality / Q000628:therapy*; D000080027:Cyclams; D005355:Fibrosis; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage; D019650:Hematopoietic Stem Cell Mobilization; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006571:Heterocyclic Compounds / Q000008:administration & dosage; D007150:Immunohistochemistry; D008099:Liver / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008115:Liver Regeneration; D051379:Mice; D013997:Time Factors
chemical_list: D001596:Benzylamines; D015415:Biomarkers; D000080027:Cyclams; D006571:Heterocyclic Compounds; D016179:Granulocyte Colony-Stimulating Factor; D002251:Carbon Tetrachloride; C088327:plerixafor
keywords: Chronic liver injury; Granulocyte-Colony Stimulating Factor; Liver regeneration; Plerixafor; Stem cells