Stem cell growth factor: in situ hybridization analysis on the gene expression, molecular characterization and in vitro proliferative activity of a recombinant preparation on primitive hematopoietic progenitor cells.
BACKGROUND
In situ hybridization of whole mouse fetuses and their tibias with a stem cell growth factor (SCGF) antisense probe demonstrated specific expression of SCGF mRNA around skeletal tissues, particularly in bone marrow cells, proliferating chondrocytes, the perichondrium and periosteum, but little expression in resting or hypertrophic chondrocytes.


METHODS
Recombinant human (rh) SCGF-alpha was purified from a conditioned medium of SCGF-alpha gene-transfected CHO cells. The molecular mass of rhSCGF-alpha, 45 kDa, was shifted down to 40 kDa by digestion with endo-O-glycosidase and sialidase, suggesting O-glycosylation of rhSCGF-alpha with sialic acids.


RESULTS
For human bone marrow CD34+Lin- cells, rhSCGF-alpha alone did not stimulate colony-formation, but small cluster-formation (10.3 +/- 2.5/1 x 10(3) CD34+Lin- cells). It promoted growth of erythroid and granulocyte/macrophage (GM) colonies in the primary culture with erythropoietin and GM colony-stimulating factor (CSF) or G-CSF, respectively, and further supported GM progenitor cells in a short-term liquid culture. In contrast, rhSCGF-alpha suppressed stem cell factor (SCF)-stimulated erythroid bursts, indicating some competitive interaction between SCGF and SCF. rhSCGF-alpha was synergistic with interleukin-3 and the flt3 ligand to enhance GM colony-growth, but not synergistic with those inducing ex vivo expansion of GM progenitor cells.


CONCLUSIONS
SCGF is selectively produced by osseous and hematopoietic stromal cells, and can mediate their proliferative activity on primitive hematopoietic progenitor cells.
Hiraoka
A
A
Department of Internal Medicine, Osaka Dental University, Osaka, Japan. hestroboy@kyoto.zaq.ne.jp
Yano Ki
K
K
Kagami
N
N
Takeshige
K
K
Mio
H
H
Anazawa
H
H
Sugimoto
S
S
D000818:Animals; D018929:Cell Culture Techniques; D002455:Cell Division / Q000187:drug effects; D003001:Cloning, Molecular / Q000379:methods; D006224:Cricetinae; D016207:Cytokines / Q000494:pharmacology; D004347:Drug Interactions; D005333:Fetus / Q000737:chemistry; D006410:Hematopoiesis / Q000187:drug effects; D016298:Hematopoietic Cell Growth Factors / Q000235:genetics* / Q000302:isolation & purification / Q000494:pharmacology*; D006412:Hematopoietic Stem Cells / Q000187:drug effects; D006801:Humans; D017403:In Situ Hybridization; D037102:Lectins / Q000235:genetics* / Q000494:pharmacology*; D037181:Lectins, C-Type; D051379:Mice; D012333:RNA, Messenger / Q000378:metabolism; D019089:Stem Cell Factor / Q000494:pharmacology; D014018:Tissue Distribution
C110532:CLEC11A protein, human; D016207:Cytokines; D016298:Hematopoietic Cell Growth Factors; D037102:Lectins; D037181:Lectins, C-Type; D012333:RNA, Messenger; D019089:Stem Cell Factor