No abstract available.
Thrombopoietin*

The main physiological function of megakaryocytes is the production of platelets, whose development, maturation and platelet production are a complex regulatory process, and are involved in many factors. In recent years it was found that the lung is also the main site of megakaryocyte-producing platelets in addition to bone marrow. Based on the findings of recent years, this review summarizes the process of megakaryocyte development, maturation and platelet production, with emphasis on the analyzing the regulatory effects of apoptotic factors, miRNA, thrombopoietin and its receptors, interleukins, transcription factors and their corresponding signal pathways on platelet production. To understand the regulatory mechanism of platelet production can help to understand the pathological mechanism of platelet-related diseases and provide new ideas for the diagnosis and treatment of platelet-related diseases.
Blood Platelets ; Bone Marrow Cells ; Megakaryocytes ; Thrombopoiesis ; Thrombopoietin

OBJECTIVE: To investigate the curative effect of simply hormone and combined gamma globulin and thrombopoietin(TPO) on primary immune thrombocytopenia(PITP). METHODS: 100 patients with PITP were divided into simply drug groups, and combined drug group each for 50 cases. The patients in single drug group were given simply hormone therapy, the patients in combined drug group were given gamma globulin and thrombopoietin. The levels of TPO, platelet activating factor (PAF) were detected by DAS-ELISA. The differences of clinical curative effect, clinical indicators, biochemical indexes and adverse reactions between the two groups were compared. RESULTS: The total effective rate of combined drug group (90.00%) was obviously higher than that in single drug group (66.00%)(P<0.05). Amount of platelet infusion in combined drug group was obviously less than that in single drug group, platelet recovery time and effect onset time in combined drug group were significantly shorter than those in single drug group, and the maintaining time in combined drug group was obviously longer than that in single drug group. At the same time, the platelet peak in combined drug group was higher than that in single drug group (P<0.05). The levels of TPO, PAF between the two groups did not show statisticall significant differences before treatment (P>0.05), however, the above-mentioned indexes of two groups after treatment were lower than those before treatment (P<0.05), among them, the indexes in combined drug group were obviously lower ttan those in sigle drug group (P<0.05). The adverse reaction and mortality rate between the two groups did not show statistically significant differences(P>0.05), the recurrence rate in combined drug group(2%) was obviously lower than that in single group(14.00%) (P<0.05). CONCLUSION The curative effect of hormone, as well as gamma globulin combined with TPO to treat PITP are satisfying, can obviously improve the levels of TPO, PAF, and the drug safety is higher. but the efficacy of combined drug is surperior to single drug.
Humans ; Immunoglobulins, Intravenous ; Purpura, Thrombocytopenic, Idiopathic ; Thrombopoietin ; gamma-Globulins

Thrombopoietin (TPO) can activate hematopoietic cell proliferation by its receptor c-MPL mediated downstream pathways and induce the generation of megakaryocyte. In recent years, domestic and foreign researches have confirmed that TPO/ c-MPL pathway also plays an important role in the self-renewal and quiescence of leukemia stem cell, and its expression in acute myeloid leukemia (AML) also indicates the chemotherapy resistance and poor prognosis. In this article, the research progress of the roles of TPO/c-MPL pathway in chemotherapy resistance, prognosis of AML patients, and the application of TPO/ c-MPL receptor agonists in AML were summarized briefly.
Humans ; Leukemia, Myeloid, Acute ; Neoplasm Proteins ; Proto-Oncogene Proteins/metabolism* ; Receptors, Cytokine ; Receptors, Thrombopoietin ; Signal Transduction ; Thrombopoietin

Cytokines such as erythropoietin (EPO) and thrombopoitein (TPO) and so on, which stimulate hematopoiesis, can regulate self-renewal, proliferation, differentiation, maturation and programmed cell death of hematopoietic cells through specifically binding to surface receptors. Recently random phage display peptide libraries and other screening methods have been used to isolate mimetic including small peptides and non-peptides molecules, which can mimic the same effects as cytokines, such as EPO and TPO, and demonstrate the similar potency and activity as EPO and TPO in a panel of in vitro biological assays and in animal experiments. These approaches are critical to further research of interactive mechanisms between cytokine and receptor, receptor activation and rational design of other desired cytokine mimetic. This review concisely introduced recent advances in research on mimetic of EPO, TPO and other cytokines and future directions.
Animals ; Cytokines ; pharmacology ; Erythropoietin ; pharmacology ; Hematopoiesis ; drug effects ; physiology ; Humans ; Peptide Library ; Peptides ; pharmacology ; Thrombopoietin ; pharmacology

OBJECTIVETo evaluate the impact of recombinant human thrombopoietin (rhTPO) on short-term response of immunosuppressive therapy (IST) in patients with newly diagnosed acquired severe aplastic anemia (SAA).

METHODSThe clinical data of forty adult acquired SAA patients, who treated with IST combined with rhTPO, were retrospective analyzed and the hematologic recovery were compared with patients by the IST alone during the same period. The factors affecting the short-term response were also analyzed.

RESULTSAt 3 months after IST, both the total response rate and CR+GPR rate in rhTPO group were much higher than those in control group (75.0% vs 50.0%, P=0.022; and 17.5% vs 2.5%, P=0.025). At 6 months after IST, there was no difference of total hematologic response rate in rhTPO group and control group (77.5% vs 57.5%, P=0.058), while the CR+GPR rate was still higher in rhTPO group (45.0% vs 22.5%, P=0.033). The median time of platelet transfusion independence was much shorter in rhTPO group [33(0-90) vs 53(0-75) d, P=0.019]. Patients in rhTPO group needed less platelets transfusion support. The median platelet count in rhTPO group was 29(4-95)×10⁹/L at 3 months after IST, which was much higher than that in control group [29(4-95)×10⁹/L, P=0.006]. There was no significant difference regarding overall survival between the two groups (100.0% vs 91.0%, P=0.276).

CONCLUSIONrhTPO is effective in promoting platelet recovery and improving the hematopoietic response for SAA patients with IST.

Anemia, Aplastic ; Blood Platelets ; Humans ; Immunosuppression ; Platelet Count ; Platelet Transfusion ; Recombinant Proteins ; Retrospective Studies ; Thrombopoietin

OBJECTIVETo identify the MPL L391-V392ins12 spliceosome and analyze its frequencies in patients with myeloproliferative neoplasms (MPN).

METHODSMPL aberrant spliceosome was identified through reverse transcription polymerase chain reaction (RT-PCR)combined with cloning sequencing. The mutation of this spliceosome in 248 MPN patients and 200 normal people was determined by allele-specific polymerase chain reaction (AS-PCR).

RESULTSA novel aberrant spliceosome of MPL gene (MPL L391-V392ins12)was identified, i.e. 36 bp intron was retained between exon7 and exon8, and there were 12 amino acids (EGLKLLPADIPV)inserted. MPL L391-V392ins12 mutation was detected in 19 (7.66%)of the 248 patients with MPN, including 1 (1.92%) of 52 patients with PV, 14 (9.66%) of 145 with ET, and 4 (7.84%) of 51 with PMF. And the mutation was not detected in the group of 200 normal people.

CONCLUSIONMPL L391-V392ins12 spliceosome is an aberrant spliceosome present in the MPN. It can be detected in PV, ET and PMF, and more frequently in ET and PMF. This mutation may play an important role in the process of MPN.

Humans ; Mutation ; Myeloproliferative Disorders ; genetics ; Neoplasms ; genetics ; Polymerase Chain Reaction ; Receptors, Thrombopoietin ; genetics ; Spliceosomes

AIMDesign, construction, expression in E coli and protein characteristics prediction of bimolecular thrombopoietin (T-T) with more stability, efficiency, and lower toxicity.

METHODSThe expression vectors of TPO and T-T, pET32 a(+)/TPO and pET32 a (+)/T-T, had been constructed by molecular cloning methods. Then, they were expressed in host bacterium. Their products were identified by Western blot. The protein characteristics, such as second structure, antigenicity, hydrophilicity, flexibility and isoelectric point, were predicted by DS Gene and Protscale software.

RESULTSThe expressing vectors pET32a(+)/TPO and T-T were constituted correctly and expressed in origami (DE3), and their expression efficiency were more than 40 percent of total protein. T-T was identified correctly by Western blot. DS Gene and Protscale software predict the protein characteristics of TPO sequences in T-T molecule were no change, there was high flexibility in the linker domain. But two amino acids in T-T molecule have been mutated, and an insert fragment with 34 amino acids following the linker had antigenicity, hydrophilicity, and beta-sheet structure.

CONCLUSIONWe have constructed correctly and expressed T-T with high level in E Coli. Protein characteristics prediction of T-T accords with our design.

Cloning, Molecular ; Escherichia coli ; Gene Expression ; Genetic Vectors ; Recombinant Fusion Proteins ; genetics ; Thrombopoietin ; genetics

Thrombopoietin (TPO) is a major cytokine for megakaryocytopoiesis and thrombopoiesis, and also plays an important role in the regulation of early hematopoiesis. TPO activates a number of signal pathways to exert its biological function by binding to its receptor (c-mpl). Once these signal pathways (including Jak/STAT, PI3K/Akt, Ras/MAPK) are activated, the expression of the downstream signal molecules can be changed, which then induces biological effects. Recent researches have suggested the novel functions of TPO in many systems. The receptor of TPO (c-mpl) has been shown not only present in hematological cells, but also in many other cells and organs, such as neurons, heart muscle cells, vessel endothelial cells and so on. TPO exerts a protective effect on these cells through the interaction with c-mpl. This review discusses the molecular mechanism of TPO signal and the effect of TPO on multi-nonhematopoietic cells.
Animals ; Humans ; Myocytes, Cardiac ; Neurons ; Signal Transduction ; genetics ; Thrombopoietin ; genetics ; metabolism

BACKGROUND: The megakaryopoiesis and platelet production is regulated by several hematopoietc factors such as thrombopoietin (TPO), interleukin-11 (IL-11) and interleukin-3 (IL-3). IL-11 is a potent stimulator of megakaryopoiesis in vivo, and acts primarily as a megakaryocyte maturation factor in vitro and it can act synergistically with IL-3 and TPO. We performed this study to investigate the effects of recombinant human IL-11 (rhIL-11) with other hematopoietic factors on megakaryocyte colony formation in vitro. METHODS: CD34+ cells were separated from umbilical cord blood and megakaryocyte colonies using MegaCult Assay Kit were cultured with rhIL-11, recombinant human IL-3 (rhIL-3), and recombinant human TPO (rhTPO) for 7 and 14 days. The number and percentage of CD34+ and CD41a+ cells were determined by flowcytometry. RESULTS: The number of CD41a+ cells were 0.54+/-0.05x10(4) (rhIL-11 100 ng/ml), 5.32+.-0.23x10(4) (rhIL-3 100 ng/ml), and 8.76+/-0.15x10(4) (rhTPO 50 ng/ml) of total expanded cells during the culture of the purified CD34+ cells in liquid phase for 7 days. The number of CD41a+ cells were increased to 7.47+/-0.69x10(4) (rhIL-3 rhIL-11), 11.92+/-0.19x10(4) (rhTPO rhIL-11) of total expanded cells, respectively, during the culture of the purified CD34+ cells in liquid phase for 7 days in the presence of rhIL-11 (100 ng/ml). When the purified CD34+ cells were cultured in semisolid media including various concentration of rhIL-11, the megakaryocyte colonies were not formed. When the purified CD34+ cells were cultured with rhIL-11 and rhTPO or with rhIL-11 and rhIL-3, the number of megakaryocyte colonies were increased compared with rhTPO or rhIL-3 alone. CONCLUSION: These results indicate that IL-11 exerts a potent proliferative activity to colony forming unit-megakaryocyte from human umbilical cord blood, and it acts with other hematopoietic factors synergistically
Blood Platelets ; Fetal Blood* ; Humans ; Interleukin-11* ; Interleukin-3 ; Megakaryocytes ; Thrombopoietin ; Umbilical Cord*