Mature monocytic cells enter tissues and engraft

Abstract

The goal of this study was to identify the circulating cell that is the immediate precursor of tissue macrophages. ROSA 26 marrow mononuclear cells (containing the ␤-geo transgene that encodes ␤-galactosidase and neomycin resistance activities) were cultured in the presence of macrophage colony-stimulating factor and flt3 Ligand for 6 days to generate monocytic cells at all stages of maturation. Expanded monocyte cells (EMC), the immature (ER-MP12 ؉ ) and more mature (ER-MP20 ؉ ) subpopulations, were transplanted into irradiated B6/129 F2 mice. ␤-gal staining of tissue sections from animals 15 min after transplantation demonstrated that the donor cells landed randomly. By 3 h, donor cells in lung and liver were more frequent in animals transplanted with ER-MP20 ؉ (more mature) EMC than in animals transplanted with unseparated EMC or fresh marrow mononuclear cells, a pattern that persisted at 3 and 7 days. At 3 days, donor cells were found in spleen, liver, lung, and brain (rarely) as clusters as well as individual cells. By 7 and 14 days, the clusters had increased in size, and the cells expressed the macrophage antigen F4/80, suggesting that further replication and differentiation had occurred. PCR for the neogene was used to quantitate the amount of donor DNA in tissues from transplanted animals and confirmed that ER-MP20 ؉ EMC preferentially engrafted. These data demonstrate that a mature monocytic cell gives rise to tissue macrophages. Because these cells can be expanded and manipulated in vitro, they may be a suitable target population for gene therapy of lysosomal storage diseases.

Reprogramming erythroid cells for lysosomal enzyme production leads to visceral and CNS cross-correction in mice with Hurler syndrome

“…It has been generally believed that the blood-brain barrier (BBB) in the mature brain is largely impermeable to lysosomal enzymes, and that the CNS benefits observed in some patients with LSD receiving allogeneic BMT treatment early in life (Ͻ2 years old) may depend on diapedesis of donor HSC-derived macrophage/monocytes into the brain (33). Recently, a study performed on mice with another LSD, metachromatic leukodystrophy, showed that gene-marked HSCs overexpressing relatively high levels of the aryl sulfatase A enzyme (ARSA) were far more efficient at reversing the preexisting CNS deficits (demyelination) than BMT using normal HSCs (34).…”

Hematopoietic Progenitor Cells (HPC) from Mobilized Peripheral Blood Display Enhanced Migration and Marrow Homing Compared to Steady-State Bone Marrow HPC

“…MMP-9-/-, CD18-/-, CD62ELP-/-or Rosa26βgeo mice (on a B6×129 genetic background), bred and housed at our facility, were used in some experiments; these mice were previously described. [8,9] For human HPC transplantation, NOD/SCIDβ2microglobulin-/-mice (NOD/SCIDβ2m-/-, Jackson Laboratories) were used as recipients. Mice were housed in the Specific Pathogen Free mouse vivarium of the Department of Comparative Medicine at the University of Washington, Seattle, WA, with autoclaved chow and water ad libitum.…”

Murine hematopoietic stem cells and progenitors express adrenergic receptors

“…Bone marrow, with defined sympathetic innervations is the site of hematopoiesis and is a primary source of circulating and tissue leukocytes (Bruno et al, 2001;Kennedy and Abkowitz, 1998;Lawson et al, 1992;Merad et al, 2002;Takahashi et al, 1996). Our previous work has demonstrated the association of critical trauma with sympathetic activation leading to the dynamic release of norepinephrine within the bone marrow (Jones et al, 1986;Tang et al, 2001;Tang et al, 1999).…”