Translational approaches to functional platelet production ex vivo

2016 ◽  
Vol 115 (02) ◽  
pp. 250-256 ◽  
Author(s):  
Christian A. Di Buduo ◽  
Alessandra Balduini ◽  
David L. Kaplan

SummaryPlatelets, which are released by megakaryocytes, play key roles in haemostasis, angiogenesis, immunity, tissue regeneration and wound healing. The scarcity of clinical cures for life threatening platelet diseases is in a large part due to limited insight into the mechanisms that control the developmental process of megakaryocytes and the mechanisms that govern the production of platelets within the bone marrow. To overcome these limitations, functional human tissue models have been developed and studied to extrapolate ex vivo outcomes for new insight on bone marrow functions in vivo. There are many challenges that these models must overcome, from faithfully mimicking the physiological composition and functions of bone marrow, to the collection of the platelets generated and validation of their viability and function for human use. The overall goal is to identify innovative instruments to study mechanisms of platelet release, diseases related to platelet production and new therapeutic targets starting from human progenitor cells.

Blood ◽  
1996 ◽  
Vol 88 (3) ◽  
pp. 778-784 ◽  
Author(s):  
A Ohwada ◽  
S Rafii ◽  
MA Moore ◽  
RG Crystal

Abstract Thrombopoietin (TPO, c-mpl ligand) has emerged as a major hematopoietic cytokine stimulating megakaryocyte proliferation, endomitosis, and platelet production. This study shows that a single administration of an adenovirus (Ad) vector encoding TPO (AdCMV.TPO) abrogates thrombocytopenia induced in mice by carboplatin and irradiation. Normal Balb/c mice receiving the vector had increased platelet counts peaking at 7 days and returning to baseline by day 15. Mice rendered pancytopenic with 500 rads and 1.2 mg of carboplatin had a nadir platelet count of five percent of the baseline. Mice receiving AdCMV.TPO 3 days before receiving irradiation and chemotherapy achieved a platelet nadir fourfold higher, and had significant reduction in duration of thrombocytopenia, than mice receiving the control Ad vector. Introduction of AdCMV.TPO the same day of chemotherapy and irradiation was equally effective in acceleration of platelet recovery, but administration of AdCMV.TPO 3 days after chemotherapy-radiation had little effect on platelet recovery. At 30 days after therapy bone marrow and spleen of mice treated with AdCMV.TPO were populated with a large number of polyploid megakaryocytes, but there was no evidence of circulating megakaryocytes in the liver or lungs and no pathologic bone abnormalities such as osteosclerosis or myelofibrosis. These observations suggest that an Ad vector may be an excellent delivery system to provide adequate TPO production to maintain platelet levels in circumstances associated with life-threatening thrombocytopenia.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2181-2181
Author(s):  
Yukitaka Ito ◽  
Sou Nakamura ◽  
Tomohiro Shigemori ◽  
Naoshi Sugimoto ◽  
Yoshikazu Kato ◽  
...  

Abstract Each transfusion requires 200-300 billion platelets in patients with thrombocytopenia. To continuously supply such a huge number of platelets by ex vivo generation, two distinct steps, megakaryopoiesis and platelet shedding, must be both considered. For the former, one approach is to increase the number of source cell, megakaryocytes. For example, the immortalized megakaryocyte cell line (imMKCL) system uses self-renewing megakaryocyte (MK) cell lines derived from induced pluripotent stem cells (iPSCs) (Nakamura et al., Cell Stem Cell, 2014). For the latter, there have been an idea of bioreactors whereby shedding of platelets from proplatelets could be promoted by flow-dependent shear force within the bone marrow in vivo (Junt et al., Science, 2007; Zhang et al., J Exp Med, 2012). Based upon this idea, we constructed a flow chamber type bioreactor recapitulating in vivo blood flow shear rate. However, this bioreactor failed to efficiently yield platelets, and moreover, the produced platelets had poor quality as indicated by high Annexin V levels (Exp Hematol, 2011 and unpublished result). Recently, we demonstrated two different kinetics of platelet biogenesis from bone marrow MKs, whereby either thrombopoietin (TPO) mostly regulates steady-state shedding of platelets from proplatelets, or interleukin-a (IL-1a) triggers inflammation-dependent rupture of MK cytoplasm contributing to a quick increase of platelet count at higher rate (Nishimura et al., J Cell Biol, 2015). However, the rupture type platelets revealed shorter half-life with relatively higher Annexin V levels. Therefore, to gain insights from platelet biogenesis in vivo, we focused on biophysical analysis of steady-state platelet biogenesis via proplatelets in bone marrow. Our observations strongly indicated that the presence of 'vorticity' defined by vortex turbulence in addition to shear-dependent 'stress' and 'strain' correlates with the efficient shedding of competent platelets. From this new finding, we developed an alternative bioreactor system, which enabled generation of 100 billion platelets from imMKCL in a 16L-scale liquid culture condition without any adherent machinery using two 10L-bioreactors. Furthermore, platelets generated via new bioreactors showed low Annexin V levels (<10-15%) and shortened bleeding time post transfusion into NOG mice and rabbits with thrombocytopenia, comparable to human blood product platelets. Regarding the platelet production using WAVE bag system (GE healthcare, UK), the system is already clinically available for cord blood cell expansion in most countries, but lacks adequate levels of vorticity and shear strain/stress. Accordingly, the produced platelets had high Annexin V levels (i.e., 50-65%) as well as diminished yield efficiency (P<0.001). In conclusion, our study has uncovered the novel biophysical aspect of platelet biogenesis. The application of the new set of physical parameters in constructing large sized bioreactors shall facilitate the industrialization of platelet production. Disclosures Eto: Megakaryon Co. Ltd.: Research Funding.


Blood ◽  
1996 ◽  
Vol 88 (3) ◽  
pp. 778-784 ◽  
Author(s):  
A Ohwada ◽  
S Rafii ◽  
MA Moore ◽  
RG Crystal

Thrombopoietin (TPO, c-mpl ligand) has emerged as a major hematopoietic cytokine stimulating megakaryocyte proliferation, endomitosis, and platelet production. This study shows that a single administration of an adenovirus (Ad) vector encoding TPO (AdCMV.TPO) abrogates thrombocytopenia induced in mice by carboplatin and irradiation. Normal Balb/c mice receiving the vector had increased platelet counts peaking at 7 days and returning to baseline by day 15. Mice rendered pancytopenic with 500 rads and 1.2 mg of carboplatin had a nadir platelet count of five percent of the baseline. Mice receiving AdCMV.TPO 3 days before receiving irradiation and chemotherapy achieved a platelet nadir fourfold higher, and had significant reduction in duration of thrombocytopenia, than mice receiving the control Ad vector. Introduction of AdCMV.TPO the same day of chemotherapy and irradiation was equally effective in acceleration of platelet recovery, but administration of AdCMV.TPO 3 days after chemotherapy-radiation had little effect on platelet recovery. At 30 days after therapy bone marrow and spleen of mice treated with AdCMV.TPO were populated with a large number of polyploid megakaryocytes, but there was no evidence of circulating megakaryocytes in the liver or lungs and no pathologic bone abnormalities such as osteosclerosis or myelofibrosis. These observations suggest that an Ad vector may be an excellent delivery system to provide adequate TPO production to maintain platelet levels in circumstances associated with life-threatening thrombocytopenia.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3188-3188
Author(s):  
Rakesh Verma ◽  
Aishwarya Narayanan ◽  
David Kuhrt ◽  
Lei Li ◽  
Su Su ◽  
...  

Abstract Abstract 3188 To provide molecular insight into erythroid developmental programs, including EPO- regulated aspects, we have employed transcriptome-based approaches to analyze the stage-wise development of purified murine bone marrow- derived CFUe, proerythroblasts and maturing erythroblasts. In vivo and ex vivo, these progenitors develop as KitposCD71highTer119neg; KitnegCD71highTer119neg; and KitnegCD71highTer119pos cohorts (designated as E1, E2, E3 stages, respectively). In the context of EPO- modulation, stage E1 cells exhibited ∼250 EPO- regulated target genes. In stage-E2 proerythroblasts, in contrast, 750 transcripts proved to be EPO- regulated while stage-E3 erythroblasts exhibited only select EPO- modulated genes (<50). At E1 and E2 stages, EPO- regulated targets included overlapping yet distinct sets, and this was reflected in functional sets of GO terms. Major EPO- targets at stage E1 included cell cycle and cell biogenesis genes, while in E2 proerythroblasts, negative regulators of protein kinases (and kinase activity) constituted a major EPO/EPOR target set. As E1 CFUe transitioned to E2 proerythroblasts, an unexpected transient narrowing in the complexity of overall expressed genes was exhibited. Stage- modulated global sets of transcripts included myeloid cell differentiation factors, cell number homeostasis factors and heme biosynthetic processes. As E2 proerythroblasts transitioned to E3 erythroblasts, functional GO sets were associated predominantly with dynamics in organelle and cellular compartments. In addition, HomoloGene and Connectivity Mapping approaches were applied to compare transcriptomes of stage E1, E2 and E3 murine bone marrow erythroid progenitors with four recently studied stages of human erythroid progenitor cell development (here, termed H1, H2, H3 and H4). High correlation of stage E1 m-CFUe with not only human H1 CFUe but also H2 proerythroblasts was observed (0.59 and 0.57 correlations). Stage E2 murine proerythroblasts best corresponded to H2 human proerythroblasts (0.36 correlation score), while E3 murine erythroblasts aligned closely with human H4 late stage erythroblasts (0.58 correlation score). These latter analyses provide novel transcriptome- based comparisons, and transcript specific insight, into conserved vs distinct features of murine and human erythroid development at CFUe to maturing erythroblast stages. Disclosures: No relevant conflicts of interest to declare.


2018 ◽  
Vol 2 (23) ◽  
pp. 3418-3427 ◽  
Author(s):  
Megan S. Rost ◽  
Ilya Shestopalov ◽  
Yang Liu ◽  
Andy H. Vo ◽  
Catherine E. Richter ◽  
...  

AbstractThe NFE2 transcription factor is expressed in multiple hematopoietic lineages with a well-defined role in regulating megakaryocyte biogenesis and platelet production in mammals. Mice deficient in NFE2 develop severe thrombocytopenia with lethality resulting from neonatal hemorrhage. Recent data in mammals reveal potential differences in embryonic and adult thrombopoiesis. Multiple studies in zebrafish have revealed mechanistic insights into hematopoiesis, although thrombopoiesis has been less studied. Rather than platelets, zebrafish possess thrombocytes, which are nucleated cells with similar functional properties. Using transcription activator-like effector nucleases to generate mutations in nfe2, we show that unlike mammals, zebrafish survive to adulthood in the absence of Nfe2. Despite developing severe thrombocytopenia, homozygous mutants do not display overt hemorrhage or reduced survival. Surprisingly, quantification of circulating thrombocytes in mutant 6-day-old larvae revealed no significant differences from wild-type siblings. Both wild-type and nfe2 null larvae formed thrombocyte-rich clots in response to endothelial injury. In addition, ex vivo thrombocytic colony formation was intact in nfe2 mutants, and adult kidney marrow displayed expansion of hematopoietic progenitors. These data suggest that loss of Nfe2 results in a late block in adult thrombopoiesis, with secondary expansion of precursors: features consistent with mammals. Overall, our data suggest parallels with erythropoiesis, including distinct primitive and definitive pathways of development and potential for a previously unknown Nfe2-independent pathway of embryonic thrombopoiesis. Long-term homozygous mutant survival will facilitate in-depth study of Nfe2 deficiency in vivo, and further investigation could lead to alternative methodologies for the enhancement of platelet production.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2103-2103
Author(s):  
Amanda Prislovsky ◽  
Falk Nimmerjahn ◽  
Jeffrey V. Ravetch ◽  
Carl W. Jackson ◽  
Ted S. Strom

Abstract Patients with the Wiskott-Aldrich Syndrome (WAS) have thrombocytopenia and increased platelet consumption rates, and may have reduced platelet production rates. WASP(−) mice have been reported to have only a mild thrombocytopenia. We find that when fully crossed onto the C57Bl/6J background, WASP(−) mice have a >50% reduction in platelet counts. Ex vivo labeled WASP(−)platelets are consumed 2 to 4-fold faster than are WT platelets in WT mice, and with exponential rather than linear kinetics. Clearance rates of WASP(−) platelets in WT mice, and vice versa, indicate that rapid consumption is due to factors both intrinsic and extrinsic to platelets. In vivo biotinylation demonstrates consumption rates comparable to those seen with ex vivo labeling, and shows a normal rate of consumption of WASP(−) reticulated (immature) platelets. Reticulated platelet counts are reduced, indicating that their production rate is reduced. Megakaryocytes are increased in spleen and bone marrow, and in the latter their ploidy distribution is normal, suggesting that impaired platelet production occurs at the level of thrombopoiesis. The absolute turnover rates of mature and reticulated platelets, however, indicate that maturation of the latter can account for only a fraction of the former’s turnover in either WT or WASP(−) mice. A subset of WASP(−) mice show an increased fraction of reticulated platelets and more severe thrombocytopenia, and some members of this subset also express serum anti-platelet antibodies. CMFDA-labeled WASP(−) platelets opsonized with anti-CD61(IgG1) antibody are more susceptible to ex vivo phagocytosis by bone marrow derived macrophages (BMDM) than WT platelets, and as susceptible as CD47(−/−) platelets. After opsonization with 6A6(IgG2b) antibody, WASP(−) platelets are also taken up more rapidly than WT platelets by BMDM, but less rapidly than are CD47(−/−) platelets. The in vivo consumption rate of WASP(−) platelets in WT recipients is more accelerated by opsonization with anti-CD61 antibody than is that of WT platelets. Increased phagocytosis is not due to (A) altered levels of the targeted antigens or of CD47 (B) increased exposure of phosphatidyl serine, or (C) antibody-induced activation as assayed by CD62P expression. Increased phagocytosis is not due to selective sensitivity to IgG1 vs IgG2b antibodies, as opsonization with an engineered 6A6(IgG1) antibody leads to reduced phagocytosis for both CD47(−/−) and WASP(−) platelets. Anti-CD61 opsonized platelets deficient in both WASP and CD47 show markedly increased ex vivo phagocytosis compared to platelets deficient in either protein, suggesting that platelet WASP does not function to amplify signals from platelet CD47 through macrophage SIRP-alpha. These results raise the possibility that the binding of low affinity or low titer antibodies that might have no effect on WT platelets could cause thrombocytopenia when the platelets lack WASP. Alternatively, rapid phagocytosis of opsonized WASP(−) platelets could promote a self-reinforcing cycle of increased host antigen presentation and increased immune responses to host antigens.


Blood ◽  
2001 ◽  
Vol 97 (6) ◽  
pp. 1635-1643 ◽  
Author(s):  
Lia E. Perez ◽  
Henry M. Rinder ◽  
Chao Wang ◽  
Jayne B. Tracey ◽  
Noel Maun ◽  
...  

The study of megakaryocytopoiesis has been based largely on in vitro assays. We characterize an in vivo model of megakaryocyte and platelet development in which human peripheral blood stem cells (PBSCs) differentiate along megakaryocytic as well as myeloid/lymphoid lineages in sublethally irradiated nonobese diabetic/severe combined immunodeficient (NOD-SCID) mice. Human hematopoiesis preferentially occurs in the bone marrow of the murine recipients, and engraftment is independent of exogenous cytokines. Human colony-forming units–megakaryocyte (CFU-MK) develop predominantly in the bone marrow, and their presence correlates with the overall degree of human cell engraftment. Using a sensitive and specific flow cytometric assay, human platelets are detected in the peripheral blood from weeks 1 to 8 after transplantation. The number of circulating human platelets peaks at week 3 with a mean of 20 × 109/L. These human platelets are functional as assessed by CD62P expression in response to thrombin stimulation in vitro. Exogenous cytokines have a detrimental effect on CFU-MK production after 2 weeks, and animals treated with these cytokines have no circulating platelets 8 weeks after transplantation. Although cytokine stimulation of human PBSCs ex vivo led to a significant increase in CFU-MK, CD34+/41+, and CD41+ cells, these ex vivo expanded cells provided only delayed and transient platelet production in vivo, and no CFU-MK developed in vivo after transplantation. In conclusion, xenogeneic transplantation of human PBSCs into NOD/SCID mice provides an excellent in vivo model to study human megakaryocytopoiesis and platelet production.


Author(s):  
Olga Wronikowska ◽  
Maria Zykubek ◽  
Agnieszka Michalak ◽  
Anna Pankowska ◽  
Paulina Kozioł ◽  
...  

AbstractMephedrone is a widely used drug of abuse, exerting its effects by interacting with monoamine transporters. Although this mechanism has been widely studied heretofore, little is known about the involvement of glutamatergic transmission in mephedrone effects. In this study, we comprehensively evaluated glutamatergic involvement in rewarding effects of mephedrone using an interdisciplinary approach including (1) behavioural study on effects of memantine (non-selective NMDA antagonist) on expression of mephedrone-induced conditioned place preference (CPP) in rats; (2) evaluation of glutamate concentrations in the hippocampus of rats following 6 days of mephedrone administration, using in vivo magnetic resonance spectroscopy (MRS); and (3) determination of glutamate levels in the hippocampus of rats treated with mephedrone and subjected to MRS, using ion-exchange chromatography. In the presented research, we confirmed priorly reported mephedrone-induced rewarding effects in the CPP paradigm and showed that memantine (5 mg/kg) was able to reverse the expression of this effect. MRS study showed that subchronic mephedrone administration increased glutamate level in the hippocampus when measured in vivo 24 h (5 mg/kg, 10 mg/kg and 20 mg/kg) and 2 weeks (5 mg/kg and 20 mg/kg) after last injection. Ex vivo chromatographic analysis did not show significant changes in hippocampal glutamate concentrations; however, it showed similar results as obtained in the MRS study proving its validity. Taken together, the presented study provides new insight into glutamatergic involvement in rewarding properties of mephedrone.


2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Wilfried Bürzle ◽  
Edoardo Mazza ◽  
John J. Moore

Puncture testing has been applied in several studies for the mechanical characterization of human fetal membrane (FM) tissue, and significant knowledge has been gained from these investigations. When comparing results of mechanical testing (puncture, inflation, and uniaxial tension), we have observed discrepancies in the rupture sequence of FM tissue and significant differences in the deformation behavior. This study was undertaken to clarify these discrepancies. Puncture experiments on FM samples were performed to reproduce previous findings, and numerical simulations were carried out to rationalize particular aspects of membrane failure. The results demonstrate that both rupture sequence and resistance to deformation depend on the samples' fixation. Soft fixation leads to slippage in the clamping, which reduces mechanical loading of the amnion layer and results in chorion rupturing first. Conversely, the stiffer, stronger, and less extensible amnion layer fails first if tight fixation is used. The results provide a novel insight into the interpretation of ex vivo testing as well as in vivo membrane rupture.


2004 ◽  
Vol 167 (6) ◽  
pp. 1113-1122 ◽  
Author(s):  
Sergei A. Kuznetsov ◽  
Mara Riminucci ◽  
Navid Ziran ◽  
Takeo W. Tsutsui ◽  
Alessandro Corsi ◽  
...  

The ontogeny of bone marrow and its stromal compartment, which is generated from skeletal stem/progenitor cells, was investigated in vivo and ex vivo in mice expressing constitutively active parathyroid hormone/parathyroid hormone–related peptide receptor (PTH/PTHrP; caPPR) under the control of the 2.3-kb bone-specific mouse Col1A1 promoter/enhancer. The transgene promoted increased bone formation within prospective marrow space, but delayed the transition from bone to bone marrow during growth, the formation of marrow cavities, and the appearance of stromal cell types such as marrow adipocytes and cells supporting hematopoiesis. This phenotype resolved spontaneously over time, leading to the establishment of marrow containing a greatly reduced number of clonogenic stromal cells. Proliferative osteoprogenitors, but not multipotent skeletal stem cells (mesenchymal stem cells), capable of generating a complete heterotopic bone organ upon in vivo transplantation were assayable in the bone marrow of caPPR mice. Thus, PTH/PTHrP signaling is a major regulator of the ontogeny of the bone marrow and its stromal tissue, and of the skeletal stem cell compartment.


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