Objective: To reveal the crucial toxic components of ambient fine particles (PM_2.5) that affect the maturation and differentiation of megakaryocytes. Methods: Human megakaryocytes were exposed to the organic fractions, metallic fractions and water-soluble fractions of PM_2.5 at two exposure doses (i.e. actual air proportion concentration or the same concentration), respectively. The cell viability was performed to screen the non-cytotoxic levels of toxic components of PM_2.5 using the CCK-8 assay. CellTiter-Blue assay, morphological observation, flow cytometry analysis and WGA staining assay were used to evaluate the cell morphological changes, occurrence of DNA ploidy, alteration in the expressions of biomarkers and platelet formation, which were key indicators of the maturation and differentiation of megakaryocytes. Results: Compared to the control group, both metallic and organic components of PM_2.5 resulted in a lag in megakaryocytes with an increase in cell volume and the onset of DNA ploidy. Flow cytometry analysis showed that CD33 (the marker of myeloid-specific) decreased and CD41a (a megakaryocyte maturation-associated antigen) increased in metallic and organic components of PM_2.5 treatment groups. Moreover, compared to the control group, budding protrusions increased in metallic and organic components of PM_2.5 treatment groups. The water-soluble components had no effect on the maturation and differentiation of macrophages. Conclusion: Metallic and organic components of PM_2.5 are the crucial toxic components that promote the maturation and differentiation of megakaryocytes.
Biomarkers ; DNA/pharmacology* ; Humans ; Megakaryocytes/chemistry* ; Particulate Matter/toxicity* ; Sincalide/pharmacology* ; Water/pharmacology*

Abivertinib, a third-generation tyrosine kinase inhibitor, is originally designed to target epidermal growth factor receptor (EGFR)-activating mutations. Previous studies have shown that abivertinib has promising antitumor activity and a well-tolerated safety profile in patients with non-small-cell lung cancer. However, abivertinib also exhibited high inhibitory activity against Bruton's tyrosine kinase and Janus kinase 3. Given that these kinases play some roles in the progression of megakaryopoiesis, we speculate that abivertinib can affect megakaryocyte (MK) differentiation and platelet biogenesis. We treated cord blood CD34⁺ hematopoietic stem cells, Meg-01 cells, and C57BL/6 mice with abivertinib and observed megakaryopoiesis to determine the biological effect of abivertinib on MK differentiation and platelet biogenesis. Our in vitro results showed that abivertinib impaired the CFU-MK formation, proliferation of CD34⁺ HSC-derived MK progenitor cells, and differentiation and functions of MKs and inhibited Meg-01-derived MK differentiation. These results suggested that megakaryopoiesis was inhibited by abivertinib. We also demonstrated in vivo that abivertinib decreased the number of MKs in bone marrow and platelet counts in mice, which suggested that thrombopoiesis was also inhibited. Thus, these preclinical data collectively suggested that abivertinib could inhibit MK differentiation and platelet biogenesis and might be an agent for thrombocythemia.
Acrylamides/pharmacology* ; Animals ; Blood Platelets/drug effects* ; Cell Differentiation ; Megakaryocytes/drug effects* ; Mice ; Mice, Inbred C57BL ; Piperazines/pharmacology* ; Pyrimidines/pharmacology*

OBJECTIVE: To investigate the effect of Rheb1 in the development of mouse megakaryocyte-erythroid progenitor cells and its related mechanism. METHODS: Rheb1 was specifically knocked-out in the hematopoietic system of Vav1-Cre;Rheb1^fl/fl mice(Rheb1^Δ/Δ mice). Flow cytometry was used to detect the percentage of red blood cells in peripheral blood and erythroid cells in bone marrow in Vav1-Cre;Rheb1^fl/fl mice and control mice. The CFC assay was used to detect the differentiation ability of Rheb1 KO megakaryocyte-erythroid progenitor cells and control cells. Real-time fluorescence quantification PCR was used to detect the relative expression of PU.1,GATA-1,GATA-2,CEBPα and CEBPβ of Rheb1 KO megakaryocyte-erythroid progenitor cells and control cells. Rapamycin was added to the culture medium, and it was used to detect the changes in cloning ability of megakaryocyte-erythroid progenitor cells from wild-type mice in vitro. RESULTS: After Rheb1 was knocked out, the development and stress response ability of megakaryocyte-erythroid progenitor cells in mice were weaken and the differentiation ability of megakaryocyte-erythroid progenitor cells in vitro was weaken. Moreover, the expression of GATA-1 of megakaryocyte-erythroid progenitor cells was decreased. Further, rapamycin could inhibit the differentiative capacity of megakaryocyte-erythroid progenitor cells in vitro. CONCLUSION Rheb1 can regulate the development of megakaryocyte-erythroid progenitor cells probably through the mTOR signaling pathway in mice.
Animals ; Cell Differentiation ; Erythrocytes ; Flow Cytometry ; Megakaryocyte-Erythroid Progenitor Cells ; Megakaryocytes ; Mice ; Signal Transduction

Tubulin affects platelets count through the control of mitosis and the formation of pro-platelets during the maturation of megakaryoblast to platelets. Tubulin is involved in maintaining the integrity of platelet skeleton, and also participates in the change of platelet morphology during platelet activation. Some new anti-tumor drugs targeting cell mitosis are trying to reduce the effect on tubulin in order to reduce the side effect of drugs on platelet formation. In some patients with thrombocytopenia, the variation and polymorphism of the tubulin gene affect the structure of microtubule multimers, which leads to the decrease of platelet formation. This review summarized the latest progresses of tubulin in the regulation of megakaryopoiesis and thrombopoiesis.
Blood Platelets ; Humans ; Megakaryocytes ; Platelet Count ; Thrombopoiesis ; Tubulin

Actinin/genetics* ; Anemia ; Blood Platelets/pathology* ; Female ; Humans ; Male ; Megakaryocytes ; Mutation, Missense ; Pedigree ; Thrombocytopenia/genetics*

Objective: To establish an intramedullary transplantation model of primary megakaryocytes to evaluate the platelet-producing capacity of megakaryocytes and explore the underlying regulatory mechanisms. Methods: Donor megakaryocytes from GFP-transgenic mice bone marrow were enriched by magnetic beads. The platelet-producing model was established by intramedullary injection to recipient mice that underwent half-lethal dose irradiation 1 week in advance. Donor-derived megakaryocytes and platelets were detected by immunofluorescence staining and flow cytometry. Results: The proportion of megakaryocytes in the enriched sample for transplantation was 40 to 50 times higher than that in conventional bone marrow. After intramedullary transplantation, donor-derived megakaryocytes successfully implanted in the medullary cavity of the recipient and produce platelets, which showed similar expression of surface markers and morphology to recipient-derived platelets. Conclusion: We successfully established an in vivo platelet-producing model of primary megakaryocytes using magnetic-bead enrichment and intramedullary injection, which objectively reflects the platelet-producing capacity of megakaryocytes in the bone marrow.
Animals ; Blood Platelets ; Bone Marrow ; Bone Marrow Cells ; Bone Marrow Transplantation ; Humans ; Megakaryocytes/metabolism* ; Mice

OBJECTIVE: To explore the phenotypic and genetic characteristics of acute megakaryoblastic leukemia (AMKL) in young children accompany by WT1, MLL-PTD and EVI1, in order to improve the diagnosis level of AMKL. METHODS: EDTA-K RESULTS: White blood cell count was 12.3× 10 CONCLUSION Acute megakaryocytic leukemia has unique and complex phenotypic and genetics characteristics.
Bone Marrow ; Child ; Child, Preschool ; Chromosome Aberrations ; Humans ; Karyotyping ; Leukemia, Megakaryoblastic, Acute/genetics* ; MDS1 and EVI1 Complex Locus Protein ; Megakaryocytes ; Oncogene Proteins, Fusion ; WT1 Proteins

OBJECTIVE: To investigate the effect of enhanced autophagy in megakaryocyte to proplatelet formation in children with immune thrombocytopenia(ITP). METHODS: Giemsa staining and immunofluorescence staining were used to observe megakaryocyte morphology and proplatelet formation, Western blot was used to determine the expression of cytoskeleton protein and autophagy related protein. Autophagr regulation drugs Rap or 3-MA was used to regulate autophagy of megakaryocytes. RESULTS: Some vacuole-like structures was found in ITP megakaryocytes of the children, the expression of LC3II/I (ITP 1.32±0.18； Ctrl 0.49±0.16，P<0.05) and Atg5-Atg12 (ITP 0.69±0.17； Ctrl 0.12±0.08，P<0.05) was significantly higher in ITP children as compared with those in control group. The immu- nofluorescence staining showed that the cytoskeleton arrangement in megakaryocytes of ITP children was abnormal, and the phosphorylation of myosin light chain was also increased(ITP 0.74±0.09, Ctrl 0.05±0.02，P<0.05). In vitro, inducer or inhibitor of autophagy could regulate the production of proplatelet and the expression of cell cycle related protein, including CyclinD1（Veh 1.08±0.12; Rap 0.46±0.04; Rap+3-MA 0.70±0.03）, CyclinD2（Veh 0.47±0.04; Rap 0.27±0.04; Rap+3-MA 0.41±0.03）, P21（Veh 0.15±0.01; Rap 0.04±0.01; Rap+3-MA 0.05±0.01）. CONCLUSION Enhanced autophagy is the key factor of poor proplatelet formation in megakaryocytes of ITP children.
Autophagy ; Blood Platelets ; Humans ; Megakaryocytes ; Purpura, Thrombocytopenic, Idiopathic ; Thrombocytopenia

OBJECTIVE: To explore the method for inducing the differentiation of bone marrow cells into megakaryocytes in vitro so as to use for evaluating the activity of traditional Chinese medicines. METHODS: The bone marrow cells were separated from femurs and tibias of mice. The experiments were divided into 4 groups: control (no adding cytokines), TPO (adding 50 ng/ml TPO), TPO+SCF (50 ng/ml+50 ng/ml) and TPO+SCF+IL-6+IL-9 (50 ng/ml+50 ng/ml+20 ng/ml+20 ng/ml). The bone marrow cells in 4 groups were cultured in vitro for 6 d. Then the cell growth status was observed by the inverted microscopy, and the cell count was detected by using the automatic cell counter. The ratio and absolute count of megakaryocytes were detected by flow cytometry. RESULTS: Compared with control, three induction methods could stimulate the differentiation of bone marrow cells into megakaryocytes in vitro. TPO could slightly enhance the differentiation of bone marrow cells into megakaryocytes. Both the combination of TPO and SCF, and the combination of TPO, SCF, IL-6 and IL-9 could intensively stimulate proliferation of bone morrow cells and promote the differentiation of bone marrow cells into megakaryocytes. The addition of IL-6 and IL-9 could decrease the proliferation of non-megakaryocytes, but promote the differentiation of bone marrow cells into megakaryocytes. CONCLUSION The optimized differentiation of bone marrow cells into megakaryocytes has been completed by co-induction regimen of TPO, SCF, IL-6 and IL-9, which can be used to screen and evaluate traditional Chinese medicines promoting formation of platelets.
Animals ; Bone Marrow Cells ; Cell Count ; Cell Differentiation ; Cell Division ; Cells, Cultured ; Interleukin-3 ; Megakaryocytes ; Mice ; Stem Cell Factor ; Thrombopoietin

OBJECTIVE: To investigate the influencing factors on prognosis of adult patients with chronic primary immune thrombocytopeuia (ITP) after rituximab treatment and predictive value of platelet (Plt) count. METHODS: Clinical data of 52 adult patients with chronic primary ITP treated with rituximab from January 2012 to December 2016 were retrospectively analyzed, including 32 patients for failed in treatment as group A and 20 patients for succeeded in treatment as group B. The independent risk factors influencing the clinical efficacy of rituximab were analyzed. The influence of CD41 megakaryocyte count in bone marrow diagnosed for first time on the response rate of patients with 1-year followed-up were observed, and the Plt count were calculated to predict the clinical efficacy index and the best cut-off point. RESULTS: The CD41 megakaryocyte count in bone marrow for first time treatment in group B were significantly higher than that in group A (P＜0.05). Multivariate Logistic regression analysis showed that the number of CD41 megakaryocytes in bone marrow＜150 at first diagnosis was the independent risk factor influencing the clinical efficacy of rituximab (OR=5.40，95%CI：1.82-15.66，P=0.00). The response rate of 1-year followed-up in patients with CD41 megakaryocyte count ≥150 at first diagnosis was significantly higher than that of CD41 megakaryocyte count ＜150 (P＜0.05). The Plt count level in group B was significantly lower than that in group A at the 3rd, 14th, 21th, 30th, 60th, 90th, 180th, 270th and 360th days after first treatment with rituximab (P＜0.05). ROC curve analysis showed that the best cut-off point for Plt count was 50×10/L and AUC was 0.68 at the 14th day after first treatment with rituximab (95%CI: 0.57-0.78, P=0.00). The predictive sensitivity and specificity of clinical efficacy in adult patients with chronic primary ITP treated with rituximab were separately 48.73% and 87.58%, and the AUC in 30th and 60th day after rituximab treatment were separately 0.74 (95%CI: 0.64-0.87, P=0.00), 0.93 (95%CI：0.82-0.98，P=0.00). CONCLUSION Adult patients with chronic primary ITP may possess long-term remission after rituximab treatment, but the prognosis is poor for patients with bone marrow megakaryocyte count ＜150. The Plt counts in 14th, 30th and 60th days after rituximab treatment can effectively predict the long-term clinical efficacy and guide the formulation of treatment plans.
Adult ; Humans ; Megakaryocytes ; Platelet Count ; Prognosis ; Purpura, Thrombocytopenic, Idiopathic ; Retrospective Studies ; Rituximab