Aryl hydrocarbon receptor biology and xenobiotic responses in hematopoietic progenitor cells

Studying the biological functions of the aryl hydrocarbon receptor (AhR) other than its function in xenobiotic drug metabolism may answer the questions as to why AhR orthologues have long been conserved phylogenically widely in the animal kingdom, and why homologues have diverged from nonvertebrate species such as nematodes and drosophila to all the vertebrate species. In this review, we focused on the mechanism of longevity possibly derived from evolution of AhRs and compared the functional difference of hematopoietic progenitors between wild-type (AhR^+/+) mice and AhR-deficiencies (AhR^+/−, AhR^−/−). Particular advantages found in wild-type mice compared with AhR-deficiencies were as follows: first, higher antioxidative function in the hematopoietic microenvironment with low oxidative tension seemed to have developed with the evolution of AhR; second, primitive hematopoietic progenitor-cell-specific deceleration and dormancy of cell-cycle regulation may have developed also with AhR evolution, which keeps hematopoietic progenitor cell compartment dormant without extinction by continuous differentiation; third, the consequent evolution of genomic stabilization with a longer lifespan in wild-type mice developed with the evolution of AhR. Experimentally, mice showed a significant extension of lifespan in a gene-dosage-dependent manner with a delayed onset of leukemogenicity. Another possible additional advantage observed in wild-type mice, the mechanism of which is not yet clarified, is an improved efficiency of fertilization in wild-type mice as compared with AhR-deficiencies, which seems to have developed with the evolution of AhR. Four advantages altogether, including the anti-aging feature mentioned above may have induced the AhR molecule to diverge various of species in the animal kingdom.     

Effect of antiserum on transplantable hematopoietic colony-forming units during Rauscher leukemia development.

Studies have been carried out to determine the sensitivity of hematopoietic CFU-S from Rauscher leukemic mice to an antiserum against the disease prepared in syngeneic mice. Test of this antiserum against Rauscher virus prior to injection showed it to be effective both in vitro and in vivo. At the same time, normal serum was shown to be without effect either against the CFU-S or against the virus. Spleen CFU-S were obtained from control and leukemic mice over a sequence of days following Rauscher virus injection and assayed by transplantation technique. Prior to transplantation these were incubated in vitro in either normal syngeneic serum or syngeneic antiserum. Incubation with antiserum had no effect on CFU-S obtained from the spleens of normal mice. However, incubation in this antiserum of spleen CFU-S from Rauscher leukemic mice resulted in a reduction of up to 50% in their colony-forming ability. Additional tests with guinea pig complement suggested that the levels of inactivation seen are not complement limited. This antiserum-induced reduction in colony formation was first evident in the second week after the injection of virus, coincident with the onset of splenomegaly in the leukemic mice. Thereafter, sensitivity of CFU-S to the antiserlm could be detected up to the terminal point of the leukemia (44 days).     

乌贼墨对小鼠造血干细胞、粒-单系祖细胞及外周白细胞的影响

目的探讨乌贼墨对小鼠造血干细胞、粒-单系祖细胞及外周血WBC的影响。方法用不同剂量的乌贼墨灌胃正常小鼠、环磷酰胺(Cy)和辐射骨髓损伤模型小鼠,采用造血祖细胞体外培养方法和实验血液学技术,检测小鼠骨髓造血干细胞生成数(CFU-S)、粒-单系祖细胞集落生成数(CFU-GM)和外周血WBC数量。结果乌贼墨能够显著提高正常小鼠CFU-S,CFU-GM和外周血WBC数量,有效拮抗模型小鼠体内CFU-S,CFU-GM及外周WBC的降低,并显著促进模型小鼠上述各指标的恢复。结论乌贼墨具有显著的促进小鼠骨髓粒系造血作用。其作用机制可能通过调节机体的免疫机能,诱导机体产生粒/单核细胞集落刺激因子和多种细胞因子,促进造血细胞的增殖,并诱导造血细胞向粒单系细胞分化。     

白介素和集落刺激因子对5-Fu处理小鼠脾集落形成的影响

给小鼠静脉注射5-fluorouracil(5-Fu),4日后将鼠脾细胞与各种细胞因子混合培养观察集落形成情况,结果表明IL-3作用于小鼠脾细胞CFU-S阶段,其作用与IL-3的剂量有关,红细胞生成素(EPO)作用于红细胞系CFU-S以下的分化成熟,IL-6,G-CSF,GM-CSF作用于粒细胞系统的分化成熟,IL-3与EP0,IL-6,G-CSF和GM-CSF均有协同作用。     

Cytotoxic and radiosensitizing effects of misonidazole on hematopoiesis in normal and tumor-bearing mice

Misonidazole is a 2-nitroimidazole hypoxic cell radiosensitizing agent currently undergoing clinical trials. Preliminary studies have shown that misonidazole is toxic to human hematopoietic stem cells. A survey of the effects of misonidazole on a variety of murine hematopoietic stem cells was undertaken. No cytotoxicity or radiosensitization could be demonstrated when misonidazole was administered in vivo, in assays of transplantable spleen colony cells (CFU-S), endogenous spleen colony cells and committed granulocyte-macrophage precursors (CFU-C). The ability of misonidazole to radiosensitize hypoxic CFU-S was confirmed. Misonidazole was toxic to bone marrow when incubated in vitro in liquid cultures for long periods at higher concentrations than that attainable in vivo. CFU-C proliferation was also assessed in animals bearing Lewis lung tumor. No toxicity could be demonstrated when there was a marked increase in CFU-C activity following tumor implantation or when the tumors had grown large enough to have a significant hypoxic portion. These studies indicate that misonidazole is not toxic to murine hematopoiesis in vivo, but there are indications that it may be toxic in situations in which relatively high concentrations are maintained for long periods of time.     

牛膝精对辐照小鼠造血干细胞和红系造血祖细胞的影响

目的探讨牛膝精（ABE）对辐照小鼠造血干细胞（以CFU-S表示）和早期红系造血祖细胞[以红系爆式集落形成单位（BFU-E）表示]和晚期红系造血祖细胞[以晚期红系集落形成单位（CFU-E）表示]的影响。方法采用脾集落形成和造血祖细胞培养技术,观察了牛膝精对辐照小鼠脾重、造血干细胞、早期红系造血祖细胞和晚期红系造血祖细胞的影响。结果该药能使受照鼠脾重及脾集落数明显提高,但不能刺激早、晚期红系造血祖细胞的活性。结论牛膝精能刺激造血干细胞的增殖,但对其向红系分化无明显影响。     

TC-1基质细胞系对造血干、祖细胞的刺激作用

TC-1基质细胞系是从小鼠骨髓细胞长期液体培养中分离出来的细胞系,其条件培养液中具有多种生物活性物质,被认为多因子分泌的细胞系。TC-1条件培养液与正常小鼠骨髓细胞共同孵育,然后通过粒、单系祖细胞(CFU-GM)半固体培养试验,脾结节形成试验,放射保护试验及流式细胞仪测定骨髓细胞的周期特点,证实了TC-1细胞系能分泌粒、单系集落刺激活性物质(GM-CSA)及体外对多能造血干细胞具有保存作用。     

Demand-control of proliferative activity in the hemopoietic system of lethally irradiated mice during transfusion-induced regeneration

The extent of cell proliferation in the hemopoietic system after bone marrow transfusion of fatally irradiated mice depends on the regeneration of proliferative capacity. This may be modified by the demand for differentiated cells in the peripheral blood. This demand was suppressed by induction of transfusion plethora prior to 800 rad whole body irradiation and bone marrow transfusion. Controls were non-plethoric recipients. For 6 days the following parameters were measured: hemopoietic proliferation by the 125-iodo-deoxyuridine (125-IUdR) incorporation technique, CFU-S content and spleen colony histology. There are three general observations from spleen and marrow with respect to 125-IUdR uptake in plethoric mice: (1) initial higher 125-IUdR uptake, (2) reduced rate of increase of 125-IUdR incorporation, (3) this rate of increasing 125-IUdR uptake in spleen was more depressed than in marrow. On day 6 cellularity and CFU-S in spleen was below, and in marrow above that of the control. These data suggest that initially after fatal irradiation of control mice differentiation of transfused CFU-S predominates over proliferation. Later as the mice become anemic and erythropoietin is produced the stimulation to proliferate is greater in the control than in the plethoric mice in which erythrocytic proliferation is suppressed. These data suggest that there are multiple feedback loops that regulate regeneration in the spleen and the bone marrow. These differences may be connected with the microenvironment that preferentially initiates erythropoiesis in the spleen before the marrow and granulopoiesis in the marrow before the spleen.