Adult bone marrow cells can differentiate into hemopoietic cells and endothelial cells but not into other lineage cells in normal growth and normal life

There have been reports that bone marrow cells (BMCs) can differentiate into various cells and tissues and that BMCs improve the function of the injured organs or reduce the organ damage, thereby rescuing the individuals from death. However, these reports also noted that injuries were induced in the organs. Therefore, it is not clear whether BMCs can differentiate into parenchymal cells in organs in normal life or whether BMCs can supply organ-specific stem cells. In this paper, we examine whether adult BMCs could contribute to the development of various organs in normal development after birth and in normal life. BMCs from adult eGFP mice (8 weeks old) were injected into the liver of newborn C57BL/6 mice. The existence of donor-derived cells in various organs was examined 1 year after the injection. In the organs of recipient mice, some of the CD45⁺ hemopoietic cells (1.4–13.2%) and CD31⁺ endothelial cells (0–2.2%) expressed eGFP, though no other lineage cells did so. These results suggest that adult BMCs can differentiate into not only hemopoietic cells but also vascular endothelial cells, but cannot differentiate into other lineage cells in normal growth and normal life.     

bFGF重组腺病毒转染骨髓间质干细胞促进VEGF的表达

目的探讨碱性成纤维生长因子(bFGF)重组腺病毒转染骨髓间质干细胞(MSCs)促进VEGF的表达。方法采用酶联免疫吸附(ELISA)法对转染bFGF重组腺病毒的MSCs实验用小型猪急性心梗模型血清中VEGF含量进行测定。结果细胞移植后即刻组Ⅰ与组ⅡVEGF含量无统计学意义(P>0.05),移植后第1w两者比较就有显著差异(P<0.01),而且组ⅠVEGF含量达高峰,第2w、第4w组ⅠVEGF含量与组Ⅱ比较差异仍有统计学意义(P<0.05)。结论bFGF重组腺病毒转染骨髓间质干细胞促进VEGF的表达。     

Increased apoptosis in bone marrow B lymphocytes but not T lymphocytes in myelodysplastic syndrome

The hallmark of myelodysplastic syndrome (MDS) is enhanced apoptosis in myeloid, erythroid, and megakaryocytic cells in the bone marrow leading to ineffective hematopoiesis. Recent studies suggested that immunological and microenvironmental factors play a role in the pathophysiology of this disease. We report a significant increase in apoptosis in bone marrow B lymphocytes in MDS as compared to that found in acute myeloid leukemia and healthy controls. Furthermore, we demonstrate that patients with refractory anemia with excess blasts in transformation (RAEB-T) had apoptosis levels in lymphocytes similar to those seen in other subtypes of MDS. Our findings suggest that the alterations in B lymphocytes in the form of increased apoptosis can be seen in MDS and support the concept that immune modulation plays a role in the pathophysiology of MDS.     

Interleukin-1 alpha also induces granulocyte-macrophage colony-stimulating factor in immature normal bone marrow cells.

The cytokine interleukin-1 (IL-1) plays a role in the regulation of normal as well as leukemic hematopoiesis. In acute myeloid leukemia (AML), IL-1 induces autocrine granulocyte/macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor (TNF) production, and these factors may then synergistically induce proliferation in AML blast cells. In this report, we show that IL-1 stimulates DNA synthesis of highly enriched normal bone marrow blast cells (CD34 positive, adherent cell depleted, CD3/CD14/CD15 negative). The stimulative effect of IL-1 can be blocked with neutralizing anti-TNF alpha and anti-GM-CSF antibodies and, most efficiently, by the combination of anti-TNF alpha and anti-GM-CSF, but not with anti-G-CSF antibody, suggesting that IL-1-induced proliferation was initiated through TNF and GM-CSF release. Concentrations of TNF and GM-CSF increased in the culture medium of normal bone marrow blast cells after IL-1 induction. Of the IL-1-induced cells, 12% were positive for GM-CSF mRNA by in situ hybridization, as opposed to 6% of non-induced cells. Thus, in addition to its effect on leukemic blast cells, IL-1 also acts on normal marrow blast cells. We propose a scheme where IL-1 stimulation of normal bone marrow blast cells leads to the induction of TNF alpha and GM-CSF, which in association stimulate DNA synthesis efficiently according to a paracrine or autocrine mechanism within the marrow blast cell compartment.     

腺病毒介导的人骨形态发生蛋白-7基因转染大鼠骨髓基质干细胞及其表达

目的 利用人骨形态发生蛋白-7(hBMP-7)腺病毒表达载体(Ad-hBMP-7)转染大鼠骨髓基质干细胞(BMSC)的方法,观察Ad-hBMP-7转染后对BMSC分化的影响,探讨基冈治疗的可能性.方法 获取Wistar大鼠BMSC,并分为3组:Ad-hBMP-7转染组、Ad-绿色荧光蛋白(Ad-GFP)转染组、未转染组.将Ad-hBMP-7和Ad-GFP的病毒液分别转染体外培养的大鼠BMSC,用RT-PCR法检测hBMP-7 mRNA的表达,7 d后用Western blot法检测hBMP-7的蛋白表达,同时进行碱性磷酸酶(ALP)染色.结果 在Ad-hBMP-7转染组,RT--PCR可检测到hBMP-7 mRNA的表达(470 bp),Western blot可检测到hBMP-7蛋白分泌(相对分子质量为15×103),转染后第10天ALP染色多数细胞-胞浆呈棕黑色阳性着色;而Ad-GFP转染组和未转染组ALP染色阳性细胞少见并且未检测到hBMP-7蛋白分泌.结论 Ad-hBMP-7基因可高效转染BMSC,促进BMSC向成骨细胞转化,为利用hBMP-7开展局部基因治疗的研究奠定了基础.     

Identification of immunosuppressant-induced apoptosis in a murine B-cell line and its prevention by bcl-x but not bcl-2.

Cyclosporin A, FK-506, and rapamycin are immunosuppressants often used as pharmacological probes to study lymphocyte activation and physiological cell death (PCD). Because cyclosporin A and FK-506 are known to prevent PCD in T-cell hybridomas and thymocytes, we used these reagents, as well as rapamycin, to determine whether they alter the pathway leading to apoptosis in murine WEHI-231 cells following surface IgM cross-linking. We observed that the immunosuppressants themselves induced PCD in WEHI-231 cells, but only in sublines susceptible to anti-IgM-mediated apoptosis. PCD was preceded by growth arrest and characterized by the DNA fragmentation pattern typical of apoptosis. In B-cell lines resistant to anti-immunoglobulin- and immunosuppressant-induced PCD, cyclosporin A, FK-506, and rapamycin caused growth arrest. PCD was also induced by inhibitors of protein synthesis in WEHI-231 cells but not in the mature B-cell line BAL-17. Immunosuppressant-induced and protein synthesis inhibitor-induced PCD, but not growth arrest, could be prevented by the overexpression of bcl-xL, while transfection with bcl-2 did not affect PCD or cell cycle arrest. These results suggest that bcl-2 and bcl-xL may control partially independent systems to inhibit PCD in lymphoid cells and that PCD in B and T cells may be differentially regulated.     

Lymphokine-activated killer cells selectively kill tumor cells in bone marrow without compromising bone marrow stem cell function in vitro

Although it has been demonstrated that lymphokine-activated killer (LAK) cells kill tumor cells in a selective way without being toxic to a variety of normal cells, contradictory results exist about the possible toxicity of natural killer (NK) and LAK cells for hematopoietic progenitor cells. Therefore, the cytolytic activity and growth inhibitory effects of LAK cells on normal bone marrow progenitor cells and the ability of LAK cells to eliminate neoplastic hematopoietic cells from populations of bone marrow cells in vitro was studied. The results of these experiments show the following: (1) LAK cells have little cytolytic activity against normal bone marrow cells; (2) normal bone marrow cells fail to cold target compete for the killing of the hematopoietic tumor cell lines K562 and HL60 or freshly frozen acute myelocytic leukemia (AML) blast cells by LAK cells; (3) LAK cells inhibit the growth of K562 and HL60 to more than 90% in clonogenic assays; (4) LAK cells have no inhibitory effect on hematopoietic progenitor growth in CFU-GM (colony-forming unit- granulocytes, macrophages), CFU-E (colony-forming unit-erythrocytes), BFU-E (burst-forming units-erythrocytes), or CFU-GEMM (colony-forming unit-granulocytes, erythrocytes, macrophages, megakaryocytes) assays. These results indicate that LAK cells have low toxicity for normal bone marrow and that LAK activity against tumor cells is not adversely affected by the presence of normal bone marrow cells. The differences in cytolysis and growth inhibition of neoplastic hematopoietic cells and hematopoietic progenitor cells by LAK cells in vitro could create a therapeutic index that might allow the use of LAK cells for cleansing of the autologous bone marrow graft and for adjuvant therapy in combination with autologous bone marrow transplantation without compromising the reconstitution of the bone marrow in the host.     

Rapamycin induces apoptosis in monocyte- and CD34-derived dendritic cells but not in monocytes and macrophages.

Rapamycin (Rapa), a recently introduced immunosuppressive drug, seems to be effective in preventing acute allograft rejection. Although its antiproliferative effect on T lymphocytes has been investigated extensively, its effect on the initiators of the immune response, the dendritic cells (DCs), is not known. Therefore, the effect of Rapa on monocyte- (mo-DCs) and CD34(+)-derived DCs in vitro but also on other myeloid cell types, including monocytes and macrophages, was examined. The present study shows that Rapa does not affect phenotypic differentiation and CD40L-induced maturation of mo-DCs. However, Rapa dramatically reduced cell recovery (40%-50%). Relatively low concentrations of Rapa (10(-9) M) induced apoptosis in both mo-DCs and CD34(+)-derived DCs, as visualized by phosphatidylserine exposure, nuclear condensation and fragmentation, and DNA degradation. In contrast, Rapa did not affect freshly isolated monocytes, macrophages, or myeloid cell lines. The sensitivity to Rapa-induced apoptosis was acquired from day 2 onward of mo-DC differentiation. Rapa exerts its apoptotic effect via a reversible binding to the cytosolic receptor protein FKBP-12, as demonstrated in competition experiments with FK506, which is structurally related to Rapa. Partial inhibition of Rapa-induced apoptosis was obtained by addition of ZVAD-fmk, which implies caspase-dependent and caspase-independent processes. The fact that Rapa exerts a specific effect on DCs but not on monocytes and macrophages might contribute to the unique actions of Rapa in the prevention of allograft rejection and other immune responses.     

阿托伐他汀主要经AMP蛋白激酶而非PI3K/Akt信号通路抑制猪骨髓间充质干细胞凋亡

目的 骨髓间充质干细胞移植治疗急性心肌梗死的效果受梗死后局部恶劣微环境限制,前期研究已证实他汀类药物可通过改良心肌微环境提高移植疗效,但具体机制不详.本研究旨在观察阿托伐他汀( Ator)对体外缺氧无血清(H/SF)诱导的猪骨髓间充质干细胞凋亡的影响并探索其作用机制及通路.方法 猪骨髓间充质干细胞分正常对照组、H/SF组、浓度梯度(0.001～10 μmol/L)Ator处理组、AMP蛋白激酶(AMPK)通路抑制剂compound C组(CC组),Ator+ CC组、磷脂酰肌醇3激酶(PI3K)/丝氨酸苏氨酸激酶(AKt)通路拮抗剂LY294002组(LY组)、Ator+ LY组.流式细胞仪检测各组细胞凋亡比例,Western blot检测AMPK、Akt、内皮型一氧化氮合酶(eNOS)蛋白及其磷酸化水平,实时聚合酶链反应(Real Time-PCR)检测AMPK、Akt和eNOS基因表达水平.结果 Ator 0.01～10 μmol/L组间充质干细胞凋亡比例显著低于H/SF对照组(1.94％ ～6.10％比10.94％,P＜0.01或0.05),Ator+ CC组间充质干细胞凋亡比例显著高于1μmol/L Ator组(4.94％±0.98％比2.59％ +0.84％,P＜0.01),而Ator+ LY组细胞凋亡比例与1μmol/L Ator组比较差异无统计学意义(2.02％±0.45％比2.59％ +0.84％,P＞0.05).Ator浓度梯度组AMPK、Akt和eNOS基因表达增加伴AMPK和eNOS磷酸化水平提高(P＜0.01或0.05).eNOS的磷酸化水平与AMPK磷酸化显著相关(r =0.599,P=0.004),而与Akt磷酸化水平无显著相关(P =0.263).结论 阿托伐他汀可抑制H/SF诱导的猪骨髓间充质于细胞凋亡,该效应主要与AMPK信号通路介导的eNOS活化有关,本实验条件下PI3K/Akt信号通路不起主要作用.     

Recombinant interleukin 3 induces interleukin 2 receptor expression on early myeloid cells in normal human bone marrow.

Human interleukin 3 (IL-3) is a multipotential cytokine that supports the growth of early hematopoietic progenitors and promotes their response to other, later-acting cytokines. We found that IL-3 was able to induce the expression of interleukin 2 (IL-2) receptor (IL-2R) (CD25) on a subset of early myeloid cells in normal human bone marrow that had been first depleted of mature hematopoietic cells and E-rosette-positive T cells by treatment with soybean lectin and sheep erythrocytes (SBA-E-BM). Immunofluorescence analysis revealed that the CD25+ cells were contained almost entirely within the lymphoblastoid gate of the IL-3-cultured marrow. CD25 was undetectable on freshly isolated marrow and less than 10% CD25+ cells could be detected following liquid culture at 37 degrees C in the presence of 10% human serum, 10% fetal calf serum, or under serum-free conditions. Addition of IL-3 (100 U/ml) significantly increased the expression of CD25 to 37%, 31%, and 24%, respectively. CD25 could also be induced by granulocyte-macrophage colony-stimulating factor (GM-CSF), but no IL-2R was detectable following exposure to granulocyte colony-stimulating factor (G-CSF), macrophage colony-stimulating factor (M-CSF), interleukin 1 (IL-1), interleukin 4 (IL-4), or IL-2. Expression of CD25 was dependent on the dose of IL-3 or GM-CSF added and was maximal within 24 h of exposure. Two-color immunofluorescence analysis demonstrated that CD25 was not expressed by cells of lymphoid lineage or by mature monocytes, but rather was present on cells that coexpressed CD13, CD33, CD34, MY8, and HLA-DR, and that lacked CD14 or CD11b, thus placing the CD25+ cells at or near the myeloblast stage of differentiation. An identical phenotype was found for CD25+ cells induced by GM-CSF. Cycloheximide completely inhibited the IL-3-induced expression of CD25, indicating the necessity for protein synthesis, and although most of the CD25+ cells were in G0/G1 phase, 25% of the cells were in S or G2M phase, indicating that receptor expression was not cell-cycle dependent. The p75 chain of IL-2R was not detected on the CD25+ cells. IL-3 was also found to directly induce CD25 in greater than 46% of SBA-E-BM enriched for CD34+ cells by panning. Consistent with the expression of only p55 IL-2R, the functional activity of IL-2 on enriched CD34+ cells exposed to IL-3 could not be demonstrated in either granulocyte-macrophage colony-forming unit (CFU-GM) assays or proliferation assays.(ABSTRACT TRUNCATED AT 400 WORDS)     

Recombinant E1-deleted adenovirus vector induces apoptosis in two lung cancer cell lines.

Although replication-defective adenoviruses (Ads) are used as vectors for delivering therapeutic genes to cancer cells, various effects of the viruses on the proliferation of lung cancer cells have been reported. Experiments were carried out to determine whether or not E1-deleted Ad vectors (Ad5-CMV-lacZ) affected cell kinetics in two different types of lung cancer cell line in vitro. A dose-dependent relationship was measured between the vector multiplicity of infection (MOI) and the efficiency of lacZ gene transfer to lung cancer cells. The growth curves of vector-infected cells were shifted to the right compared with those of vehicle-exposed cells in a vector MOI-dependent fashion. The slowed cell proliferation resulted from both increased cell death and slower cell cycle progression of the vector-infected cells. The morphology of vector-exposed cells revealed apoptotic features including nuclear condensation and fragmented nuclei. These results indicate that using a higher vector MOI causes a higher gene transfer rate, but may induce apoptosis of infected cells. Although vector-induced apoptosis may be advantageous in inhibiting tumour growth, apoptosis of vector-infected cells may also reduce transgene expression in cancer cells. Minimization of the induction of apoptosis of vector-infected cells is important for the prolongation of the transduction efficiency of Ad vectors.     

Histone deacetylase inhibitor induces DNA damage,which normal but not transformed cells can repair

Histone deacetylase inhibitors (HDACi) developed as anti-cancer agents have a high degree of selectivity for killing cancer cells. HDACi induce acetylation of histones and nonhistone proteins, which affect gene expression, cell cycle progression, cell migration, and cell death. The mechanism of the tumor selective action of HDACi is unclear. Here, we show that the HDACi, vorinostat (Suberoylanilide hydroxamic acid, SAHA), induces DNA double-strand breaks (DSBs) in normal (HFS) and cancer (LNCaP, A549) cells. Normal cells in contrast to cancer cells repair the DSBs despite continued culture with vorinostat. In transformed cells, phosphorylated H2AX (γH2AX), a marker of DNA DSBs, levels increased with continued culture with vorinostat, whereas in normal cells, this marker decreased with time. Vorinostat induced the accumulation of acetylated histones within 30 min, which could alter chromatin structure-exposing DNA to damage. After a 24-h culture of cells with vorinostat, and reculture without the HDACi, γH2AX was undetectable by 2 h in normal cells, while persisting in transformed cells for the duration of culture. Further, we found that vorinostat suppressed DNA DSB repair proteins, e.g., RAD50, MRE11, in cancer but not normal cells. Thus, the HDACi, vorinostat, induces DNA damage which normal but not cancer cells can repair. This DNA damage is associated with cancer cell death. These findings can explain, in part, the selectivity of vorinostat in causing cancer cell death at concentrations that cause little or no normal cell death.     

Mutant N-ras induces myeloproliferative disorders and apoptosis in bone marrow repopulated mice

Mutations that activate the N-ras oncogene are among the most frequently detected genetic alterations in human acute myeloid leukemias (AMLs), Philadelphia chromosome-negative myeloproliferative disorders (MPDs), and myelodysplastic syndromes (MDSs). However, because N-ras has not been shown to induce these disorders in an in vivo model, the role of N-ras in the evolution of myeloid leukemia is unclear. To investigate the potential of N-ras to induce myeloid leukemia, lethally irradiated mice were reconstituted with bone marrow (BM) cells infected with a retroviral vector carrying activated N-ras. Approximately 60% of these mice developed hematopoietic disorders, including severe MPDs resembling human chronic myelogenous leukemia (CML) or AML with differentiation (French-American-British [FAB] classification M2). Other reconstituted mice succumbed to hematopoietic defects that were pathologically similar to human MDSs. The latter disorders appeared to be due to a myeloid impairment that was demonstrated by enumeration of day-12 colony-forming units-spleen (CFU-S) and by in vitro colony assays. A high level of apoptosis associated with thymic atrophy and peripheral blood (PB) lymphopenia was also evident in N-ras reconstituted mice. Our results are consistent with a model in which antiproliferative effects are a primary consequence of N-ras mutations and secondary transforming events are necessary for the development of myeloid leukemia. This is the first report of an in vivo model for N-ras induced MPD and leukemia.     

XAF1基因诱导胰腺癌细胞株BxPC3凋亡的实验研究

目的 探讨Ad5/F35腺病毒介导的XAF1基因诱导胰腺癌细胞BxPC3凋亡及其可能的作用机制.方法 将前期构建的重组腺病毒Ad5/F35-XAF1感染胰腺癌细胞BxPc3.采用半定量RTPCR、蛋白质印迹检测法检测感染前后BxPC3细胞XAF1 mRNA和蛋白表达的变化;运用Annexin-V/PI和TUNEL法检测细胞的凋亡率;免疫蛋白印迹法检测细胞Caspase-3、PARP、Caspase-8和Bcl-2蛋白的表达.结果 Ad5/F35-XAF1感染后,BxPC3细胞的XAF1 mRNA和蛋白表达明显增高,与空白组和Ad5/F35-Null对照组比较,差异显著(P＜0.05);两种方法 检测的细胞凋亡率分别为(19.90±3.09)%、(9.29±2.13)%,较Ad5/F35-Null组的(6.72±0.76)%、(2.73±0.51)%和空白组的(7.22±1.53)%、(1.56±0.47)%均有显著差异(P＜0.01);Caspase-3、PARP、Caspase-8蛋白表达显著增强,Bcl-2表达降低.结论 Ad5F35-XAF1重组腺病毒感染胰腺癌细胞BxPC-3能明显诱导细胞的凋亡,其机制可能是激活死亡受体途径和线粒体途径.     

Acadesine activates AMPK and induces apoptosis in B-cell chronic lymphocytic leukemia cells but not in T lymphocytes

Acadesine, 5-aminoimidazole-4-carboxamide (AICA) riboside, induced apoptosis in B-cell chronic lymphocytic leukemia (B-CLL) cells in all samples tested (n = 70). The half-maximal effective concentration (EC(50)) for B-CLL cells was 380 +/- 60 microM (n = 5). The caspase inhibitor Z-VAD.fmk completely blocked acadesine-induced apoptosis, which involved the activation of caspase-3, -8, and -9 and cytochrome c release. Incubation of B-CLL cells with acadesine induced the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK), indicating that it is activated by acadesine. Nitrobenzylthioinosine (NBTI), a nucleoside transport inhibitor, 5-iodotubercidin, an inhibitor of adenosine kinase, and adenosine completely inhibited acadesine-induced apoptosis and AMPK phosphorylation, demonstrating that incorporation of acadesine into the cell and its subsequent phosphorylation to AICA ribotide (ZMP) are necessary to induce apoptosis. Inhibitors of protein kinase A and mitogen-activated protein kinases did not protect from acadesine-induced apoptosis in B-CLL cells. Moreover, acadesine had no effect on p53 levels or phosphorylation, suggesting a p53-independent mechanism in apoptosis triggering. Normal B lymphocytes were as sensitive as B-CLL cells to acadesine-induced apoptosis. However, T cells from patients with B-CLL were only slightly affected by acadesine at doses up to 4 mM. AMPK phosphorylation did not occur in T cells treated with acadesine. Intracellular levels of ZMP were higher in B-CLL cells than in T cells when both were treated with 0.5 mM acadesine, suggesting that ZMP accumulation is necessary to activate AMPK and induce apoptosis. These results suggest a new pathway involving AMPK in the control of apoptosis in B-CLL cells and raise the possibility of using acadesine in B-CLL treatment.