CXCR4 induction in hematopoietic progenitor cells from Fanca(-/-), -c(-/-), and -d2(-/-) mice.
OBJECTIVE
Bone marrow failure is a near-universal occurrence in patients with Fanconi anemia (FA) and is thought to result from exhaustion of the hematopoietic stem cell (HSC) pool. Retrovirus-mediated expression of the deficient protein corrects this phenotype and makes FA a candidate disease for HSC-directed gene therapy. However, inherent repopulation deficits and stem cell attrition during conventional transduction culture prevent therapeutic chimerism.


METHODS
We previously reported rapid transduction protocols to limit stem cell losses after ex vivo culture. Here we describe a complementary strategy intended to improve repopulation through upregulation of chemokine receptor (CXCR) 4, a principal factor in hematopoietic homing.


RESULTS
Using murine models with transgenic disruption of Fanca, -c, and -d2, we found that c-kit(+) and sca-1(+) progenitor cells express levels of CXCR4 comparable with those of wild-type littermates. Lineage-depleted progenitor populations rapidly upregulated CXCR4 transcript and protein in response to cytokine stimulation or hypoxia, regardless of genotype. Hypoxia conditioning of lineage-depleted Fancc(-/-) progenitors also reduced oxidative stress, improved in vitro migration and led to improved chimerism in myeloablated recipients after transplantation.


CONCLUSIONS
These studies provide evidence that CXCR4 regulation in progenitor cells from transgenic mice representing multiple FA genotypes is intact and that modulation of homing offers a potential strategy to offset the FA HSC repopulation deficiency.
Skinner
Amy M
AM
Department of Pediatrics, Oregon Health and Science University, Portland, OR 97239, USA.
O'Neill
S Lee
SL
Grompe
Markus
M
Kurre
Peter
P
D000818:Animals; D015687:Cell Hypoxia; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology; D004195:Disease Models, Animal; D005199:Fanconi Anemia / Q000235:genetics* / Q000473:pathology; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005838:Genotype; D006412:Hematopoietic Stem Cells / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018384:Oxidative Stress; D019718:Receptors, CXCR4 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
C514936:CXCR4 protein, mouse; D016207:Cytokines; D019718:Receptors, CXCR4