Platelet-derived growth factor plays a critical role to convert bone marrow cells into glomerular mesangial-like cells.
BACKGROUND
Despite increasing interest in bone marrow-derived stem cells, little is known about critical factors that determine their fates both in vitro and in vivo. Recently, we have reported that bone marrow is a reservoir for glomerular mesangial cells in rats. To find a key factor responsible for the differentiation of bone marrow-derived cells into mesangial cells, we established a new culture system of rat bone marrow, which is based on serial replating and differential attachment to collagen types I and IV.


METHODS
Bone marrow cells that did not adhere to collagen type I within 24 hours were transferred to collagen type IV-coated dishes. Then, the cells attached to collagen type IV in the following 24 hours were maintained in the presence of 2% horse serum, 200 ng/mL of platelet-derived growth factor (PDGF)-BB, and 1 micromol/L of all-trans retinoic acid. In vivo effect of PDGF-B was also examined by introducing human PDGF-B gene into glomeruli.


RESULTS
After cultivation under the above condition for 7 days, approximately 14% of cells expressed Thy-1 and desmin, both of which are markers for rat mesangial cells. Thy-1++/desmin+ cells were stellate-shaped, and contracted in response to angiotensin II. When human PDGF-B gene was overexpressed in the glomeruli of chimeric rats whose bone marrow was transplanted from enhanced green florescent protein (EGFP) transgenic rats, the number of EGFP+ mesangial cells increased. This effect was canceled by prior introduction of a neutralizing molecule that is composed of PDGF receptor-beta ligand binding site and IgG-Fc.


CONCLUSIONS
These results indicate that PDGF-B plays a critical role to direct bone marrow-derived cells toward mesangial-like cells both in vitro and in vivo.
Suzuki
Akira
A
Department of Internal Medicine and Therapeutics, Osaka University School of Medicine, Suita, Osaka, Japan.
Iwatani
Hirotsugu
H
Ito
Takahito
T
Imai
Enyu
E
Okabe
Masaru
M
Nakamura
Hiroyuki
H
Isaka
Yoshitaka
Y
Yamato
Masaya
M
Hori
Masatsugu
M
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D030801:Animals, Genetically Modified; D001854:Bone Marrow Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003893:Desmin / Q000378:metabolism; D005920:Glomerular Mesangium / Q000166:cytology* / Q000502:physiology; D049452:Green Fluorescent Proteins; D066298:In Vitro Techniques; D008164:Luminescent Proteins / Q000235:genetics; D020574:Proto-Oncogene Proteins c-sis / Q000235:genetics* / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018800:Thy-1 Antigens / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D003893:Desmin; D008164:Luminescent Proteins; D020574:Proto-Oncogene Proteins c-sis; D018800:Thy-1 Antigens; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D049452:Green Fluorescent Proteins