Bone Marrow Hemopoietic Progenitor Cells Research Articles

Protective effect of HS-6101 on rhesus monkeys with severe hematopoietic acute radiation sickness

This study was purposed to investigate the protective effects of lipoprotein HS-6101(6101) on rhesus monkey total body irradiated with 7.0 Gy ⁶⁰Coγ-ray. A total of 30 health adult rhesus monkeys were randomly divided into symptomatic therapy (ST), WR2721 and HS-6101 30, 90 and 270 mg/kg groups (n = 6), the rhesus monkeys of each groups were injected with physiological saline 0.3 ml/kg, WR-2721 30 mg/kg, or HS-6101 30, 90 and 270 µg/kg, respectively. All agents were once intramuscularly injected at 1 hr prior irradiation. General observation, peripheral blood cell counts, colony forming unite assay of bone marrow hemopoietic progenitor cells, and histopathological examination were performed. The results showed that animals in symptomatic therapy group begin to die on the 13(th) day and 4 animals died within 24 days, the average survival time was 18.2 ± 4.3 days; 2 animals in WR-2717 groups died on day 15.8 and day 18.5 post irradiation respectively. 1 animal in HS-6101 270 mg/kg group died on day 35.8, all other animals survived. Nadirs of peripheral blood white blood cells, neutrophils and platelets of animals in HS-6101 treatment groups were significantly higher than those in other 2 groups including ST and WR-2721 groups, and the hemopoietic recovery were also significantly speeding up(P < 0.05 and 0.01). In vitro results showed that HS-6101 obviously promoted 7.0 Gy ⁶⁰Coγ irradiated monkey's bone marrow mononuclear cells to form various hematopoietic progenitor cell colonies (P < 0.05 and 0.01) . Compared with symptomatic therapy and WR-2717 groups, bone marrow histopathological changes in HS-6101 treatment groups showed more active hemopoietic cell proliferation and higher density structure. It is concluded that HS-6101 90 µg/kg treatment can promote the bone marrow recovery of 7.0 Gy ⁶⁰Coγ irradiated monkey, alleviate their animal symptom, simplify the treatment measures and improve the animal survival rate. The HS-6101 shows remarkable radioprotective effects as compared with the currently internationally acknowledged radioprotectant of WR-2721.

Expression of ABCG2 (BCRP) in mouse models with enhanced erythropoiesis.

Haem is a structural component of numerous cellular proteins which contributes significantly to iron metabolic processes in mammals but its toxicity demands that cellular levels must be tightly regulated. Breast Cancer Resistance Protein (BCRP/ABCG2), an ATP Binding Cassette G-member protein has been shown to possess porphyrin/haem efflux function. The current study evaluated the expression and regulation of Abcg2 mRNA and protein levels in mouse tissues involved in erythropoiesis. Abcg2 mRNA expression was enhanced in bone marrow hemopoietic progenitor cells from mice that were treated with phenylhydrazine (PHZ). Abcg2 mRNA expression was increased particularly in the extramedullary haematopoietic tissues from all the mice models with enhanced erythropoiesis. Haem oxygenase (ho1) levels tended to increase in the liver of mice with enhanced erythropoiesis and gene expression patterns differed from those observed in the spleen. Efflux of haem biosynthetic metabolites might be dependent on the relative abundance of Abcg2 or ho1 during erythropoiesis. Abcg2 appears to act principally as a safety valve regulating porphyrin levels during the early stages of erythropoiesis and its role in systemic haem metabolism and erythrophagocytosis, in particular, awaits further clarification.

Megakaryocytes Contribute To The Establishment Of The Bone Marrow Environment By Expressing Extracellular Matrix proteins

Introductionthe bone marrow microenvironment consists of various types of cells and their secreted extracellular matrix components that surround capillary-venous sinusoids, and plays a key role in the regulation of hematopoiesis. In general, extracellular matrix components interact with each other to form a structural framework that supports tissue organization and positional cues that regulate cellular processes. Megakaryocytes are rare cells in the bone marrow and, besides platelet release, growing evidences attribute new functions to these cells in the generation and maintenance of the bone marrow cell niche. Recent evidences, by our group, demonstrated that megakaryocytes are involved in matrix deposition and remodeling, as demonstrated by their role in fibronectin fibrillogenesis and the expression of matrix cross-linking enzymes, such as factor XIIIa, essential in the dynamic of megakaryocyte-matrix component interactions. Interestingly, individual extracellular matrix components were demonstrated to play a role in the regulation of megakaryocytes development in vitro. Fibronectin was shown to regulate megakaryocyte maturation and proplatelet extension, while type III and type IV collagens were demonstrated to support proplatelet formation in vitro. In contrast, type I collagen is an important physiological inhibitor of platelet release in vitro. However, little is known about the exact localization as well as function of these matrix components in vivo. Resultsin this work we have analyzed the spatial distribution of megakaryocytes and extracellular matrix components by immunofluorescence in murine femur sections. We found that megakaryocytes were predominantly located in the femur diaphysis with only 20% of megakaryocytes within 50μm from the endosteal surface and more than 80% of megakaryocytes located less than 50 μm from a sinusoid. Correlation between megakaryocyte distance from sinusoids and dimension suggested a gradient of maturing megakaryocytes towards the vascular niche. Next, we deciphered bone marrow extracellular matrix component composition by western blotting and mapped the location in situ of different collagens (I, III, IV, VI) and glycoproteins (fibronectin, laminin). We found that all these proteins were differently located in the endosteal and sinusoidal districts supporting the concept that regulation of hemopoiesis, in the bone marrow, may also depend from matrix distribution. Further, we showed, for the first time, that megakaryocytes were surrounded by a pericellular matrix mainly composed of fibronectin, laminin and type IV collagen. Interestingly, these three proteins were also demonstrated to promote thrombopoietin-dependent megakaryocyte differentiation in in vitro cultures of bone marrow hemopoietic progenitor cells. Finally, fibronectin, laminin and type IV collagen were also demonstrated to be expressed and synthesized by differentiated megakaryocytes in vitro as demonstrated by PCR and western blotting analysis. Most importantly, megakaryocyte expression of these extracellular matrix components was up-regulated in vivo during bone marrow reconstitution upon drug induced myelosuppression and, at a lesser extent, thrombocytopenia. Conclusionsall together these results suggested that megakaryocytes are important extracellular matrix component-producing bone marrow cells and that released extracellular matrix components support megakaryopoiesis and concur to the generation of bone marrow niches. Disclosures:No relevant conflicts of interest to declare.

Effects of Angelica polysaccharide on erythrocyte immunity and marrow hematopoiesis in chickens

To investigate the effects of Angelica polysaccharide on erythrocyte immunity and marrow hematopoiesis in chickens, Angelica polysaccharide was used for the study of immunity and hematinic mechanism in order to provide basis for clinical reference. In this experiment, three gradient dosages (50, 100, 150 mg/kg body weight) of Angelica polysaccharide were drenched to the control group and the anemia groups, respectively. The anemia chickling model was made by abdominal injection of cyclophosphamide (CY) for 6 days (80 mg/kg·day).Red blood cell-C3b receptor (RBC-CR1) and red blood cell-immune complex (RBC-IC) rosette rates were measured and analyzed. Ectogenetic semi-solid culture medium of bone marrow hemopoietic progenitor cells was used to observe Angelica polysaccharide and separated serum fromAngelica polysaccharide treatment on the proliferation of colony-forming unit-erythrocyte (CFU-E), burst-forming unit-erythrocyte (BFU-E) and colony-forming unit-granulocyte macrophage (CFU-GM). The results showed that Angelica polysaccharide can significantly increase RBC-CR1 rosette rate in the healthy chicken groups (p 0.05). At the same time, Angelica polysaccharide can restore the RBC- CR1 rosette rate and the RBC-IC rosette rate caused by cyclophosphamide to the normal level. Serum containing Angelica polysaccharide can significantly facilitate the proliferation on CFU-E (p<0.01), BFU-E (p<0.01) and CFU-GM (p<0.01), but Angelica polysaccharide had no more direct proliferation on CFU-E, BFU-E and CFU-GM. This indicated that Angelica polysaccharide had the proliferation on hemopoietic progenitor cells of marrow by the change of hemopoietic factor. Key words: Polysaccharide, chicken, erythrocyte, immunity, hematopoiesis.

Effects of vasoactive intestinal peptide on phenotypic and functional maturation of dendritic cells

The present study was designed to investigate the effects of vasoactive intestinal peptide (VIP) on differentiation, maturation of dendritic cells (DCs) in vitro. DCs were derived from the murine bone marrow hemopoietic progenitor cells by culturing in RPMI 1640 complete medium supplemented with GM-CSF and IL-4 in the presence or absence of various concentrations of vasoactive intestinal peptide (VIP) and lipopolysaccharide (LPS). The phenotype of DCs was analyzed by flow cytometry. Mixed leukocyte reaction (MLR) was employed to measure the capacity of DC to stimulate the allogeneic T cells. IL-12p70 secretion by DC was examined by ELISA. In the absence of LPS, VIP, in a dose dependent manner, up-regulated the expression of CD80, CD86, CD54 and CD40, but down-regulated the expression of MHC class II molecule (Ia b). In the presence of LPS, VIP also dose dependently up-regulated the expression of CD80, CD86, CD54 and CD40, and down-regulated the expression of Ia b. The capacity to stimulate alloreactive T cells and the production of IL-12p70 by DC were significantly augmented by VIP when compared with VIP-untreated DCs. These data suggest that VIP could promote the phenotypic and functional maturation of DCs, hereby regulating the type and outcome of the conducting immune response.

Effects of Bone Marrow Hemopoietic Progenitor Cells in Asthma

近年来的研究发现,支气管哮喘(简称哮喘)的发病不单单局限于气道和肺组织,还存在一个全身性的反应机制,而骨髓造血祖细胞等在哮喘发病中的作用日益受到重视.哮喘发病过程中,不仅骨髓内祖细胞增多,核糖体顺反子表达增高,而且外周血循环及局部肺组织中造血祖细胞也增多.白细胞介素-5,9,12和嗜酸性细胞趋化因子参与了这一过程.通过研究骨髓造血祖细胞等在哮喘中的作用,人们正试图寻找哮喘治疗的新途径.

Differential Roles of Vascular Endothelial Growth Factor Receptors 1 and 2 in Dendritic Cell Differentiation

Impaired Ag-presenting function in dendritic cells (DCs) due to abnormal differentiation is an important mechanism of tumor escape from immune control. A major role for vascular endothelial growth factor (VEGF) and its receptors, VEGFR1/Flt-1 and VEGFR2/KDR/Flk-1, has been documented in hemopoietic development. To study the roles of each of these receptors in DC differentiation, we used an in vitro system of myeloid DC differentiation from murine embryonic stem cells. Exposure of wild-type, VEGFR1(-/-), or VEGFR2(-/-) embryonic stem cells to exogenous VEGF or the VEGFR1-specific ligand, placental growth factor, revealed distinct roles of VEGF receptors. VEGFR1 is the primary mediator of the VEGF inhibition of DC maturation, whereas VEGFR2 tyrosine kinase signaling is essential for early hemopoietic differentiation, but only marginally affects final DC maturation. SU5416, a VEGF receptor tyrosine kinase inhibitor, only partially rescued the mature DC phenotype in the presence of VEGF, suggesting the involvement of both tyrosine kinase-dependent and independent inhibitory mechanisms. VEGFR1 signaling was sufficient for blocking NF-kappaB activation in bone marrow hemopoietic progenitor cells. VEGF and placental growth factor affect the early stages of myeloid/DC differentiation. The data suggest that therapeutic strategies attempting to reverse the immunosuppressive effects of VEGF in cancer patients might be more effective if they specifically targeted VEGFR1.

Sensitization of bone marrow hemopoietic progenitor cells (BMC) to the interleukin-3 (IL-3) and granulocyte macrophage colony stimulating factor (GM-CSF) induced de novo synthesis of histidine decarboxylase (HDC) through the activation of beta-adrenoceptors (βAR)

Two distinct hyperpolarizing responses are produced when histamine is iontophoretically applied onto the somal membranes of identified neurons within the cerebral ganglion of Aplysia: a biphasic response consisting of a rapid component (< 5sec) usually superimposed upon a slowly developing component; or a monophasic slowly developing response 5–20 sec in duration. The reversal potential values for the fast (typically −65 mV) and the slow (typically −89 mV) responses, and their shift to new values when the external potassium or chloride concentrations were altered, revealed that the fast and slow potentials are produced predominantly by conductance increases to chloride and potassium ions, respectively.The effects of histamine H1- and H2-receptor agonists and antagonists were studied to characterize the pharmacological properties of histamine receptors mediating these two ionically dissimilar hyperpolarizing responses. The slow potassium-dependent hyperpolarization could be mimicked by several histamine analogues; the most potent tested were the H1-receptor agonist, 2-methylhistamine, and the H2-receptor agonist, 4-methylhistamine. Neither of these agents mimicked the fast chloride-dependent histamine response. The slow potassium-dependent responses induced by histamine or histamine agonists were completely and reversibly blocked by the H2-receptor antagonist, cimetidine. By contrast, the slow potassium-dependent hyperpolarizations produced by iontophoretically applied acetylcholine or by dopamine to the same neurons were unaffected by cimetidine. Other H1 and H2 antagonists tested were either ineffective, or only partially blocked the slow hyperpolarizations in a non-selective manner. The fast chloride-dependent hyperpolarizations were not selectively antagonized by any of the H1 or H2 reagents tested, although they were effectively suppressed by tubocurarine and strychnine. These data indicate that two pharmacologically distinct histamine receptors mediate potassium- and chloride-dependent hyperpolarizations in Aplysia neurons. Neither of these receptors, however, could be classified as strictly H1 or H2 according to criteria presently used in non-neuronal tissues. The selectivity and reversibility of cimetidine indicate that this particular antihistaminic could be a valuable pharmacological tool for defining putative histaminergic synapses in Aplysia and perhaps other nervous systems.

Effects of prenatal irradiation on fetal, neonate, and young adult murine hemopoiesis

B6D2F1 mice received cobalt-60 radiation on day 10.5 of gestation at doses of 50 to 300 rad at a dose rate of 40 rad per min. These animals were studied at four selected age periods: (a) day 14.5 of gestation, (b) neonate, (c) juvenile, and (d) 13 week-old adult. Fetal liver cellularity, morphology, and hemopoietic progenitor cell concentration reflected injury after 200 rad. The 15 day-old mouse spleen cellularity was affected more than bone marrow cellularity, but greater radiation injury was reflected by bone marrow hemopoietic progenitor cells. Fluctuations from normal hematopoietic values were greater in the 15 day-old juvenile than in the 9 day-old neonate, commencing with 50 rad. These included peripheral blood parameters and marrow- and spleen-derived erythroid-, granulocytic- and megakaryocytic-progenitor cells. The consequences of prenatal irradiation (150 rad) were evident in the 13 week-old mouse. This was manifested by a reduced spleen cellularity and perturbations in concentrations of hemopoietic progenitor cells in the bone marrow.