Hematopoietic origins of fibroblasts: II. In vitro studies of fibroblasts, CFU-F, and fibrocytes.
OBJECTIVE
Using transplantation of a clonal population of cells derived from a single hematopoietic stem cell (HSC) of transgenic enhanced green fluorescent protein (EGFP) mice, we have documented the hematopoietic origin of myofibroblasts, such as kidney mesangial cells and brain microglial cells. Because myofibroblasts are thought to be an activated form of fibroblasts, we tested the hypothesis that fibroblasts are derived from HSCs.


METHODS
Clones of cells derived from single cells of EGFP Ly-5.2 C57Bl/6 mice were transplanted into lethally irradiated Ly-5.1 mice. Using bone marrow and peripheral blood cells from mice showing high-level multilineage hematopoietic reconstitution, we induced growth of fibroblasts in vitro.


RESULTS
Culture of EGFP(+) bone marrow cells from clonally engrafted mice revealed adherent cells with morphology typical of fibroblasts. Flow cytometric analysis revealed that the majority of these cells are CD45(-) and express collagen-I and the collagen receptor, discoidin domain receptor 2 (DDR2). Reverse transcriptase polymerase chain reaction analysis of cultured cells demonstrated expression of procollagen 1-alpha1, DDR2, fibronectin, and vimentin mRNA. Fibroblast colonies consisting of EGFP(+) cells were observed in cultures of bone marrow cells from clonally engrafted mice, indicating an HSC origin of fibroblast colony-forming units. Culture of peripheral blood nucleated cells from clonally engrafted mice revealed EGFP(+) cells expressing collagen-I and DDR2, indicating that fibrocytes are also derived from HSCs.


CONCLUSIONS
We conclude that a population of fibroblasts and their precursors are derived from HSCs.
Ebihara
Yasuhiro
Y
Department of Veterans Affairs Medical Center, Medical University of South Carolina, Charleston, 29401-5799, USA.
Masuya
Masahiro
M
Larue
Amanda C
AC
Fleming
Paul A
PA
Visconti
Richard P
RP
Minamiguchi
Hitoshi
H
Drake
Christopher J
CJ
Ogawa
Makio
M
D000818:Animals; D002478:Cells, Cultured; D002999:Clone Cells; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D000090602:Collagen Type I, alpha 1 Chain; D003114:Colony-Forming Units Assay; D000070818:Discoidin Domain Receptors; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D011975:Receptors, Mitogen / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014184:Transplantation, Homologous; D014746:Vimentin / Q000235:genetics / Q000378:metabolism
D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D005353:Fibronectins; D012333:RNA, Messenger; D011975:Receptors, Mitogen; D014746:Vimentin; D049452:Green Fluorescent Proteins; D000070818:Discoidin Domain Receptors; D020794:Receptor Protein-Tyrosine Kinases