Donor-derived cells in the central nervous system of twitcher mice after bone marrow transplantation

The twitcher mouse is an animal model of galactosylceramidase deficiency, comparable to Krabbe's disease, a lysosomal storage disease in humans. As in most lysosomal storage diseases, neurological deterioration is a prominent feature of the disease in these mice. Transplantation of enzymatically normal congenic bone marrow was earlier found to result in prolonged survival and increased levels of galactosylceramidase in the visceral organs of twitcher mice. It is now reported that bone marrow transplantation results in increased galactosylceramidase levels in the central nervous system (CNS). Concomitantly, the levels of psychosine, a highly toxic lipid that progressively accumulates in the CNS of untreated twitcher mice, stabilized at much lower levels in the CNS of treated twitcher mice. Histologically, a gradual disappearance of globoid cells, the histological hallmark of Krabbe's disease, and the appearance of foamy macrophages capable of metabolizing the storage product were seen in the CNS. By immunohistochemical labeling it was demonstrated that these foamy macrophages were of donor origin. The infiltration of enzymatically competent, donor-derived macrophages was accompanied by extensive remyelination in the CNS. It is concluded that after bone marrow transplantation, donor-derived macrophages infiltrate the affected brain tissue and are capable of inducing a partial reversal of the enzyme deficiency.     

Origin of repopulating cells after localized bone marrow depletion

The restoration of marrow in a mechanically depleted segment of rabbit femur is locally determined and apparently initiated by cells normally resident in bone. This conclusion follows from results of two types of radiation experiments: local x-irradiation of the femur shaft immediately before depopulation and x-irradiation of the total body with exception of the femur diaphysis which was depopulated either just before or after irradiation. In contrast to the rapid initiation of marrow restoration in an unirradiated femur, there was little regeneration during the first 3 weeks in an irradiated femur. Recovery of the shielded depopulated femur in the rabbit that otherwise received total-body irradiation was similar to that in the unirradiated animal. Hence, it would appear that the seeding of circulating hemic stem cells is not essential to repopulation and that cells with hematopoietic potential are present in osseous tissue.     

Replication of the B19 parvovirus in human bone marrow cell cultures

The B19 parvovirus is responsible for at least three human diseases. The virus was successfully propagated in suspension cultures of human erythroid bone marrow from patients with hemolytic anemias; release of newly synthesized virus into the supernatants of infected cultures was observed. This culture system allowed study at a molecular level of events associated with the B19 life cycle. The B19 parvovirus replicated through high molecular weight intermediate forms, linked through a terminal hairpin structure. B19 replication in vitro was highly dependent on the erythropoietic content of cultures and on addition of the hormone erythropoietin.     

Kinetic differences in unresponsiveness of thymus and bone marrow cells

Both thymus and bone marrow cells of adult mice can be made specifically unresponsive to human gamma globulin, but each cell population displays a distinct kinetic pattern for both the induction and spontaneous loss of the unresponsive state. These kinetics appear to be much slower in the bone marrow cells than in the thymus cells. In addition, the dose of deaggregated human gamma globulin needed to induce unresponsiveness in bone marrow cells is much greater than that needed to induce unresponsiveness in thymus cells. Apparently, unresponsiveness in only one cell type is sufficient for the tolerant state to be exhibited by the intact animal.     

Induction of self-tolerance in T cells but not B cells of transgenic mice expressing little self antigen

Self-tolerance to a transgene-encoded protein, hen egg lysozyme, was examined in the T and B cell repertoires of a series of lines of transgenic mice that expressed different serum concentrations of soluble lysozyme. T cells were tolerant in all lines in which lysozyme was expressed irrespective of the antigen concentration, whereas B cell tolerance did not occur when the serum lysozyme concentration was less than 1.5 nanograms per milliliter (0.1 nM). Induction of elevated transgene expression could restore B cell tolerance. These findings support the hypothesis that autoimmune disease may in some instances arise through a bypass of T cell tolerance.     

Influence of SHIP on the NK repertoire and allogeneic bone marrow transplantation

Natural killer cell (NK) receptors for major histocompatibility complex (MHC) class I influence engraftment and graft-versus-tumor effects after allogeneic bone marrow transplantation. We find that SH2-containing inositol phosphatase (SHIP) influences the repertoire of NK receptors. In adult SHIP-/- mice, the NK compartment is dominated by cells that express two inhibitory receptors capable of binding either self or allogeneic MHC ligands. This promiscuous repertoire has significant functional consequences, because SHIP-/- mice fail to reject fully mismatched allogeneic marrow grafts and show enhanced survival after such transplants. Thus, SHIP plays an important role in two processes that limit the success of allogeneic marrow transplantation: graft rejection and graft-versus-host disease.     

The influence of allogeneic cells on the human T and B cell repertoire

Clinical transplantation is often complicated by rejection episodes, in which the immune system of the recipient reacts to the foreign transplantation (HLA) antigens on the graft. This immune response includes humoral and cellular components. In the first, B lymphocytes form antibodies to the HLA alloantigens. In the second, CD8+ T lymphocytes recognize and react to HLA class I antigens, and CD4+ T cells react to HLA class II antigens. The frequency and severity of these rejection episodes can be diminished by immunosuppressive drugs, HLA matching between donor and recipient, and immune modulation by blood transfusion. Effective HLA matching between donor and recipient is not always possible and often not necessary. Insight into the factors that influence the T and B cell repertoire after blood transfusion might lead to new approaches to improve graft survival.     

Circadian periodicity of bone marrow mitotic activity and reticulocyte counts in rats and mice

Mitotic proliferation in the bone marrow of female rats and mice kept under standardized coniditions with light from 6:00 a.m. to 6:00 p.m. exhibited a significant circadian periodicity with the greatest activity occurring from 6:00 a.m. to 12:00 noon. The reticulocyte levels in peripheral blood were highest at 8:00 a.m.     

骨髓间充质干细胞移植在卵巢早衰小鼠卵巢功能重建中应用

探讨骨髓间充质干细胞(BMSCs)移植在卵巢早衰小鼠卵巢功能重建中的应用价值。通过一次性腹腔注射环磷酰胺和白消安建立小鼠卵巢早衰(POF)模型,并随机分为建模组、BMSCs移植组和空白对照组。移植组于建模14 d经尾静脉注射绿色荧光蛋白(GFP)转基因鼠BMSCs悬液(5×10~7个·mL~(-1)),每4 d重复1次,共5次;建模组和空白对照组注射等量生理盐水。观察建模后及BMSCs移植后小鼠的一般情况、血清FSH和E2水平、卵巢组织学变化以及GFP荧光信号在卵巢内的分布。结果发现,建模组小鼠食欲明显减退,活动减少,与空白对照组相比体重显著减轻(P0.05),FSH水平显著增高(P0.05),E2水平显著降低(P0.05),卵巢体积减小,间质纤维化严重,始基卵泡、生长卵泡和成熟卵泡数均显著减少(P0.05)。BMSCs移植后,移植组小鼠体重增加,食欲增强,活动增多;28 d后FSH浓度显著低于建模组(P0.05),E2浓度、始基卵泡、生长卵泡数及成熟卵泡数均显著高于建模组(P0.05),但各项指标仍与空白对照组间存在显著性差异;荧光显微镜下可见绿色荧光信号散在分布于卵泡周围。此结果提示,BMSCs可在小鼠损伤卵巢组织中定位存活,对卵巢组织结构及内分泌功能有修复作用。     

The application of bone marrow transplantation to the treatment of genetic diseases

Genetic diseases can be treated by transplantation of either normal allogeneic bone marrow or, potentially, autologous bone marrow into which the normal gene has been inserted in vitro (gene therapy). Histocompatible allogeneic bone marrow transplantation is used for the treatment of genetic diseases whose clinical expression is restricted to lymphoid or hematopoietic cells. The therapeutic role of bone marrow transplantation in the treatment of generalized genetic diseases, especially those affecting the central nervous system, is under investigation. The response of a generalized genetic disease to allogeneic bone marrow transplantation may be predicted by experiments in vitro. Gene therapy can be used only when the gene responsible for the disease has been characterized. Success of gene therapy for a specific genetic disease may be predicted by its clinical response to allogeneic bone marrow transplantation.     

Lymphotoxin is an important T cell-derived growth factor for human B cells

Two different assays for B cell growth factors (BCGF) and an antibody against lymphotoxin were used to show that the presence of lymphotoxin in conditioned media derived from normal activated T cells and in a partially purified BCGF accounts for a substantial portion of their B cell growth-promoting activity. A competitive binding assay confirmed the presence of significant amounts of lymphotoxin in the partially purified BCGF. Recombinant lymphotoxin enhanced the proliferation of activated B cells and augmented B cell proliferation and immunoglobulin secretion induced by interleukin-2.     

骨髓基质细胞诱导的神经干细胞移植对颞叶癫痫大鼠学习记忆障碍的改善作用

   探讨骨髓基质细胞诱导的神经干细胞移植至海人酸(kanic acid,KA)致痫大鼠海马后对学习记忆障碍的改善作用,从而为干细胞移植治疗癫痫提供理论依据.体外分离大鼠骨髓基质细胞,并在特定条件下培养、诱导分化为神经干细胞.在海马内注射KA建立大鼠癫痫模型,之后把诱导的神经干细胞移植至KA致痫鼠的海马内,用Morris水迷宫测试大鼠学习记忆能力,用PCR方法检测海马内NSE、c-fos和SEZ-6基因表达,采用Western blot技术检测海马内NSE、C-FOS和SEZ-6蛋白表达.结果显示:骨髓基质细胞成功诱导分化为神经干细胞,诱导分化的神经干细胞移植到脑内可明显改善大鼠的学习记忆障碍;移植组大鼠海马内NSE、c-fos和SEZ-6基因表达下调,NSE、C-FOS和SEZ-6蛋白表达亦下调,与阳性对照组及假移植组比较,差异显著(P<0 05).说明骨髓基质细胞诱导的神经干细胞移植至KA致痫大鼠海马后对学习记忆障碍有明显的改善作用,其机制可能与NSE、c-fos、SEZ-6基因和蛋白的表达下调相关.     

BMP4在诱导骨髓间充质干细胞向生殖细胞分化中的作用

为了探讨骨形态发生蛋白4(bone morphogenetic protein 4,BMP4)在诱导骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)向生殖细胞分化中的作用,将全骨髓培养法获取小鼠BMSCs,在含10%胎牛血清(fetal bovine serum,FBS)的DMEM培养液中培养传代;取生长状态良好的第三代(P3)BMSCs,分别添加不同浓度(5、10、20、40和80ng·mL~(-1))的BMP4作为实验组,未添加BMP4为对照组。4d后,MTT法和台盼蓝染色检测细胞的增殖率和存活率,实时定量PCR(RT-qPCR)检测生殖细胞阶段特异性基因(Oct4、Dazl、Fragilis、Mvh、Nobox、Stella、Stra8和Gdf9)的表达。结果发现,BMP4浓度为5~20 ng·mL~(-1)时细胞存活率和增殖率最高;BMP4浓度为20 ng·mL~(-1)组Mvh、Fragilis、Oct-4、Dazl及Stella表达水平最高,均显著高于对照组(P0.05);Nobox表达水平则在BMP4浓度40ng·mL~(-1)组最高,且各浓度组均显著高于对照组(P0.05);各浓度BMP4组Stra8和Gdf9的表达水平均与对照组间无显著性差异(P0.05)。此结果提示,BMP4浓度在20 ng·mL~(-1)时,BMSCs的存活率、增殖率及原始生殖细胞特异性基因的表达最高;BMP4在诱导间充质干细胞向生殖细胞分化过程中起重要作用。     

A clonogenic bone marrow progenitor specific for macrophages and dendritic cells

Macrophages and dendritic cells (DCs) are crucial for immune and inflammatory responses and belong to a network of cells that has been termed the mononuclear phagocyte system (MPS). However, the origin and lineage of these cells remain poorly understood. Here, we describe the isolation and clonal analysis of a mouse bone marrow progenitor that is specific for monocytes, several macrophage subsets, and resident spleen DCs in vivo. It was also possible to recapitulate this differentiation in vitro by using treatment with the cytokines macrophage colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. Thus, macrophages and DCs appear to renew from a common progenitor, providing a cellular and molecular basis for the concept of the MPS.     

Heterozygous Beta thalassemia: balanced globin synthesis in bone marrow cells

In two patients with heterozygous beta thalassemia the rates of synthesis of the alpha and beta chains of hemoglobin were equal in nucleated red cell precursors, although beta chain synthesis was reduced in peripheral blood reticulocytes. This finding suggests a relative instability of beta chain messenger RNA in beta thalassemia.