[show abstract][hide abstract] ABSTRACT: In rodents, bone marrow-derived cells enter the brain during adult life. Allogeneic bone marrow transplantation is used to treat genetic CNS diseases, but the fate of human bone marrow and CD34(+) cells within the brain remains to be elucidated. The present study demonstrates that cells derived from human CD34(+) cells, isolated from either cord blood or peripheral blood, migrate into the brain after infusion into nonobese diabetic/severe combined immunodeficient mice. Both types of CD34(+)-derived cells differentiate into perivascular and ramified microglia. The lentiviral transfer of genes into CD34(+) cells before infusion does not modify the differentiation of human CD34(+) cells into microglia, allowing new transgenic proteins to be expressed in these cells. The transplantation of CD34(+) cells could thus be used for the treatment of CNS diseases.
Proceedings of the National Academy of Sciences 04/2004; 101(10):3557-62. · 9.74 Impact Factor
[show abstract][hide abstract] ABSTRACT: X-linked adrenoleukodystrophy (ALD) is a peroxisomal disorder (1 in 17.000) characterized by progressive demyelination of the central nervous system, adrenal insufficiency and abnormal accumulation of very-long-chain fatty acids (VLCFA) in plasma and tissues, including the brain and spinal cord white matter.The phenotypic presentation of ALD is highly variable, ranging from childhood lethal cerebral ALD to a milder adult form, adrenomyeloneuropathy (AMN), characterized by progressive spastic paraparesis and peripheral neuropathy with no brain involvement. No correlation has been observed between the accumulation of VLCFA in plasma and clinical phenotypes. Mice lacking ALD gene develop motor disability of late onset (after 15 months) that ressembles AMN.Allogeneic hematopoietic cell transplantation (HCT) can stabilize or reverse cerebral demyelination, provided the procedure is performed at an early stage of the disease. The long-term benefits of HCT are likely due to the ability of bone-marrow derived cells to enter the central nervous system and differentiate into microglia expressing normal ALD protein. The efficacy of allogenic HCT is however limited by the lack of donors and the mortality risk of the procedure. Targeting the ALD gene into hematopoietic stem cells (HSC) of ALD patients followed by reinfusion of modified cells would thus be a valuable alternative both for children and adults with cerebral ALD and/or AMN. Towards this goal, we have demonstrated that transplantation of transduced ALD CD34+ cell into NOD/SCID mice results in long-term expression of ALD protein in monocytes/macrophages derived from engrafted ALD stem cells (Benhamida S et al. 2003. Mol Ther; 7: 317–324)). In addition, we recently demonstrated that human CD34+ cells differentiate into brain microglia after transplantation in NOD/SCID mice and retain their capacity to differentitate into microglia that express recombinant ALD protein after transduction with HIV-derived vector (Asheuer M et al, PNAS, in press).In the present study, we demonstrate that transplantation of whole bone marrow cells corrects the late onset neurological phenotype of ALD mouse without any effect on brain and spinal cord VLCFA level. The injection of normal Sca-1+ cells instead of whole bone marrow cells increases the turn-over of brain microglia from 3.8% to 21.9%. The lentiviral transfer of ALD gene into ALD SCA-1+ cells prior to infusion did not modify the number of brain microglia cells expressing ALD protein. ALD gene is expressed in thymus lymphocytes of secondary recipients, indicating efficient transfer of ALD gene in hematopoietic stem cells, and no sign of malignancy was demonstrated in hematological tissues.
[show abstract][hide abstract] ABSTRACT: X-linked adrenoleukodystrophy (ALD), an inherited demyelinating disorder of the central nervous system, can be corrected by allogeneic bone marrow transplantation, likely due to the turnover of brain macrophages that are bone marrow derived. ALD is characterized by an accumulation of very long chain fatty acids (VLCFA) due to the deficiency of an ATP binding cassette transporter that imports these fatty acids in peroxisomes. Murine retroviral transduction results in metabolic correction of ALD CD34(+) cells in vitro but reinfusion of these cells into ALD patients would not provide clinical benefit owing to the absence of selective advantage conferred by transgene expression. High-efficiency transduction of ALD CD34(+) peripheral blood mobilized cells was achieved using an HIV-based vector driving ALD gene expression under the elongation factor 1 alpha promoter and a protocol without prestimulation of CD34(+) cells with cytokines prior to transduction to preserve their stem cell properties. Efficient expression of the ALD gene was demonstrated in monocytes/macrophages derived from cultures of transduced ALD CD34(+) cells and in long-term culture initiating cells. VLCFA metabolism was corrected in transduced CD34(+), CFU-derived, and LTC-derived cells, indicating that the vector-encoded ALD protein was fully functional. Transplantation of transduced ALD CD34(+) cells into NOD/SCID mice resulted in long-term expression of ALD protein in monocytes/macrophages derived from engrafted stem cells.