Human CD34⁺cells differentiate into microglia and express recombinant therapeutic protein

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 diabetic͞severe 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. U p to 20% of the total nonneuronal cell population is made of microglia (1). Microglia are ubiquitously distributed in the CNS and play a major role in the response to infectious, traumatic, inflammatory, and ischemic processes, as well as in degenerative CNS diseases, such as Alzheimer's disease, multiple sclerosis, or Parkinson's disease. The adult brain contains two subsets of microglia: the resting microglia, which ramify throughout the brain parenchyma, and the perivascular microglia, which resemble peripheral macrophages (1, 2).Following a long debate about their origin, microglia are now believed to be derived from bone marrow as liver, spleen, or lung macrophages (2). Murine bone marrow-derived cells enter the CNS and differentiate into microglia (3-5). In mice, the turnover of perivascular microglia reaches 30% 1 year after engraftment, whereas the turnover of ramified microglia is much slower (6, 7). However, the subset of bone marrow-derived cells that are the progenitors of microglia has not been characterized. In mice, transplantation of transduced bone marrow cells allows the expression of glucocerebrosidase or GFP in microglia (8, 9). In humans, there are very little data documenting the fate of bone marrow-derived cells in the CNS after bone marrow transplantation (BMT) (10, 11). However, that BMT is used to treat genetic CNS diseases like Hurler disease or X-linked adrenoleukodystrophy (ALD) (12, 13) suggests that bone marrow cells may serve as vehicles for the delivery of genes into the human CNS.Transplantation of CD34 ϩ hematopoietic cells is replacing that of whole bone marrow cells for many applications, including autotransplantation in cancer, non-HLA genoidentical BMT, and gene therapy (14-16). Human CD34 ϩ cells can be easily collected from cord blood at birth or from peripheral blood after cytokine mobilization. We studied the migration, differentiation, and distribution of human CD34 ϩ cells purified either from umbilical cord blood (UCB) or from mobilized peripheral blood (MPB) in the brain of nonobese diabetic͞severe combined immunodeficient (NOD͞SCID) mouse. Our results demonstrate that a fraction of these cells, when infused into NOD͞SCI...

A novel, neural potential of non-hematopoietic human umbilical cord blood stem cells

“…Besides our studies there are many reports from other laboratories of cord blood cells turning into brain cells i.e. neurons, astrocytes, oligodendrocytes, endothelial cells and microglia both in vitro and in vivo (Buzanska et al, 2006;Borlongan and Hess, 2006;English et al, 2006;Zandonella, 2005;Tagushi et al, 2004;Asheuer et al, 2004). Thus, the most straightforward idea is that cord blood stem cells infused systemically reach brain, differentiate into mature cell types and simply replace the lost cells.…”

Therapy of X-linked adrenoleukodystrophy

“…These differences could not be explained by allelic diversity [51]. Others found that severity of the X-ALD phenotype is correlated with expression of an other peroxisomal transporter gene (ABCD4) and of the VLCFA synthase gene BG1 [52]. Recently, we reported that functional polymorphisms of genes and proteins involved in environmental factors may also be involved, as indicated by phenotypic variability in a set of monozygotic twins [55], and the disease may putatively also be triggered by CNS traumas [14].…”

“…Additionally, it was shown that cells derived from human CD34+ cells isolated from cord blood or peripheral blood migrate into the brain after infusion into immunodeficient mice and differentiate into perivascular and ramified microglia. The lentiviral gene transfer does not modify the differentiation of human CD34+ cells into microglia [52], and human CD34+ derived microglia would likely be attracted to the sites of neuronal damage [127]. The transplantation of such transduced cells is a candidate for future treatment of several hereditary CNS diseases including X-ALD.…”

In situ-RT and immunolaser microdissection for mRNA analysis of individual cells isolated from epilepsy-associated glioneuronal tumors

“…However, the cellular identity of CD34 expressing elements remains enigmatic. 12 However, CD34 expression has been also described in activated microglia, 13,14 cellular elements frequently observed in brain tissue following epileptic attacks. In order to characterize the cellular origin of CD34-expressing cells in gangliogliomas, we employed in situ-RT primers specific for three neural lineage markers: glial fibrillary acidic protein (GFAP), neurofilament (NFM) and myelin basic protein (MBP); as well as human leukocyte antigen (HLA-DQ) and CD34.…”