Pegylated interferon alfa (pegIFN-α) can induce molecular remissions in patients with JAK2-V617F-positive myeloproliferative neoplasms (MPNs) by targeting long-term hematopoietic stem cells (LT-HSCs). Additional somatic mutations in genes regulating LT-HSC self-renewal, such as DNMT3A, have been reported to have poorer responses to pegIFN-α. We investigated whether DNMT3A loss leads to alterations in JAK2-V617F LT-HSC functions conferring resistance to pegIFN-α treatment in a mouse model of MPN and in hematopoietic progenitors from patients with MPN. Long-term treatment with pegIFN-α normalized blood parameters and reduced splenomegaly and JAK2-V617F chimerism in single-mutant JAK2-V617F (VF) mice. However, pegIFN-α in VF;Dnmt3aΔ/Δ (VF;DmΔ/Δ) mice worsened splenomegaly and failed to reduce JAK2-V617F chimerism. Furthermore, LT-HSCs from VF;DmΔ/Δ mice compared with VF were less prone to accumulate DNA damage and exit dormancy upon pegIFN-α treatment. RNA sequencing showed that IFN-α induced stronger upregulation of inflammatory pathways in LT-HSCs from VF;DmΔ/Δ than from VF mice, indicating that the resistance of VF;DmΔ/Δ LT-HSC was not due to failure in IFN-α signaling. Transplantations of bone marrow from pegIFN-α-treated VF;DmΔ/Δ mice gave rise to more aggressive disease in secondary and tertiary recipients. Liquid cultures of hematopoietic progenitors from patients with MPN with JAK2-V617F and DNMT3A mutation showed increased percentages of JAK2-V617F-positive colonies upon IFN-α exposure, whereas in patients with JAK2-V617F alone, the percentages of JAK2-V617F-positive colonies decreased or remained unchanged. PegIFN-α combined with 5-azacytidine only partially overcame resistance in VF;DmΔ/Δ mice. However, this combination strongly decreased the JAK2-mutant allele burden in mice carrying VF mutation only, showing potential to inflict substantial damage preferentially to the JAK2-mutant clone.

• MeSH
• buněčná sebeobnova MeSH
• chemorezistence * genetika   MeSH
• DNA methyltransferasa 3A * genetika   MeSH
• DNA-(cytosin-5-)methyltransferasa * genetika   metabolismus   MeSH
• hematopoetické kmenové buňky * metabolismus   patologie   účinky léků   MeSH
• interferon alfa * farmakologie   MeSH
• Janus kinasa 2 * genetika   metabolismus   MeSH
• lidé MeSH
• myeloproliferativní poruchy * genetika   patologie   farmakoterapie   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• polyethylenglykoly farmakologie   MeSH
• rekombinantní proteiny MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA methyltransferasa 3A * MeSH
• DNA-(cytosin-5-)methyltransferasa * MeSH
• DNMT3A protein, human MeSH Prohlížeč
• Dnmt3a protein, mouse MeSH Prohlížeč
• interferon alfa * MeSH
• JAK2 protein, human MeSH Prohlížeč
• Jak2 protein, mouse MeSH Prohlížeč
• Janus kinasa 2 * MeSH
• peginterferon alfa-2a MeSH Prohlížeč
• polyethylenglykoly MeSH
• rekombinantní proteiny MeSH

The clinical course of essential thrombocythemia (ET) is complicated with thrombosis which significantly impacts patients' mortality. Studies have identified JAK2V617F mutation as an independent risk factor for thrombosis. Circulating extracellular vesicles (EVs) were evaluated in several studies regarding myeloproliferative neoplasms and thrombosis as potential biomarkers. The present study investigates the relationship between JAK2V617F mutation and EVs levels in 119 ET patients. Our analyses revealed that JAK2V617F-positive patients are at a significantly increased risk of thrombosis within five years before the ET diagnosis (hazard ratio [95% CI]: 11.9 [1.7-83.7], P = 0.013), and that JAK2V617F mutation is an independent risk factor for thrombosis at ET diagnosis or during the follow-up (hazard ratio [95% CI]: 3.56 [1.47-8.62], P = 0.005). ET patients have higher levels of platelet-EVs, erythrocyte-EVs and procoagulant activity of EVs than the healthy population. Absolute and relative counts of platelet-EVs are increased in the presence of JAK2V617F mutation (P = 0.018, P = 0.024, respectively). In conclusion, our results support the role of JAK2V617F mutation in the pathogenesis of thrombosis in essential thrombocythemia through enhancing platelet activation.

• Klíčová slova
• Essential thrombocythemia, JAK2V617F mutation, extracellular vesicles, risk factor, thrombosis,
• MeSH
• esenciální trombocytemie * genetika   komplikace   patologie   MeSH
• Janus kinasa 2 * genetika   MeSH
• lidé MeSH
• mutace MeSH
• myeloproliferativní poruchy * komplikace   genetika   patologie   MeSH
• trombocyty MeSH
• trombóza * genetika   patologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• Janus kinasa 2 * MeSH

JAK 2-V617F mutation causes myeloproliferative neoplasms (MPNs) that can manifest as polycythemia vera (PV), essential thrombocythemia (ET), or primary myelofibrosis. At diagnosis, patients with PV already exhibited iron deficiency, whereas patients with ET had normal iron stores. We examined the influence of iron availability on MPN phenotype in mice expressing JAK2-V617F and in mice expressing JAK2 with an N542-E543del mutation in exon 12 (E12). At baseline, on a control diet, all JAK2-mutant mouse models with a PV-like phenotype displayed iron deficiency, although E12 mice maintained more iron for augmented erythropoiesis than JAK2-V617F mutant mice. In contrast, JAK2-V617F mutant mice with an ET-like phenotype had normal iron stores comparable with that of wild-type (WT) mice. On a low-iron diet, JAK2-mutant mice and WT controls increased platelet production at the expense of erythrocytes. Mice with a PV phenotype responded to parenteral iron injections by decreasing platelet counts and further increasing hemoglobin and hematocrit, whereas no changes were observed in WT controls. Alterations of iron availability primarily affected the premegakaryocyte-erythrocyte progenitors, which constitute the iron-responsive stage of hematopoiesis in JAK2-mutant mice. The orally administered ferroportin inhibitor vamifeport and the minihepcidin PR73 normalized hematocrit and hemoglobin levels in JAK2-V617F and E12 mutant mouse models of PV, suggesting that ferroportin inhibitors and minihepcidins could be used in the treatment for patients with PV.

• MeSH
• deficit železa * MeSH
• esenciální trombocytemie * genetika   MeSH
• fenotyp MeSH
• hemoglobiny genetika   MeSH
• Janus kinasa 2 genetika   MeSH
• mutace MeSH
• myeloproliferativní poruchy * farmakoterapie   genetika   diagnóza   MeSH
• myši MeSH
• polycythaemia vera * genetika   MeSH
• železo MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• hemoglobiny MeSH
• Janus kinasa 2 MeSH
• železo MeSH

BACKGROUND/AIM: This work aimed to prospectively evaluate the clinical significance of circulating microparticles (MPs) in relation to thrombotic risk factors and thrombotic complications in patients with BCR/ABL1-negative myeloproliferative neoplasms (MPN). PATIENTS AND METHODS: In a cohort of 206 patients with MPN, MPs' procoagulant activity was measured by the Zymuphen functional assay in 429 samples, while platelet- and erythrocyte-MPs were enumerated by flow cytometry in 558 samples. RESULTS: MPN patients had higher MP levels than the control group. The levels of MPs were higher in male patients, smokers, and those who were older than 60 years, and in the presence of JAK2V617F mutation, history of thrombosis, platelets >400×109/l, hematocrit >45%, or leukocytes >10×109/l. Cytoreductive treatment reduced MP levels, with anagrelide being associated with lower MP levels than hydroxyurea. CONCLUSION: The relationship with thrombotic risk factors indicates a possible role of MPs in the complex thrombotic mechanism, though cytoreductive treatment seems to affect this role through reducing MP levels.

• Klíčová slova
• Myeloproliferative neoplasm, anagrelide, hydroxyurea, microparticle, procoagulant activity, thrombosis,
• MeSH
• lidé MeSH
• mikropartikule * MeSH
• myeloproliferativní poruchy * farmakoterapie   genetika   MeSH
• nádory * MeSH
• trombocyty MeSH
• trombóza * etiologie   genetika   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Myeloproliferative neoplasms (MPN), comprising essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF), are hematological disorders of the myeloid lineage characterized by hyperproliferation of mature blood cells. The prediction of the clinical course and progression remains difficult and new therapeutic modalities are required. We conducted a CD34+ gene expression study to identify signatures and potential biomarkers in the different MPN subtypes with the aim to improve treatment and prevent the transformation from the rather benign chronic state to a more malignant aggressive state. We report here on a systematic gene expression analysis (GEA) of CD34+ peripheral blood or bone marrow cells derived from 30 patients with MPN including all subtypes (ET (n = 6), PV (n = 11), PMF (n = 9), secondary MF (SMF; post-ET-/post-PV-MF; n = 4)) and six healthy donors. GEA revealed a variety of differentially regulated genes in the different MPN subtypes vs. controls, with a higher number in PMF/SMF (200/272 genes) than in ET/PV (132/121). PROGENγ analysis revealed significant induction of TNFα/NF-κB signaling (particularly in SMF) and reduction of estrogen signaling (PMF and SMF). Consistently, inflammatory GO terms were enriched in PMF/SMF, whereas RNA splicing-associated biological processes were downregulated in PMF. Differentially regulated genes that might be utilized as diagnostic/prognostic markers were identified, such as AREG, CYBB, DNTT, TIMD4, VCAM1, and S100 family members (S100A4/8/9/10/12). Additionally, 98 genes (including CLEC1B, CMTM5, CXCL8, DACH1, and RADX) were deregulated solely in SMF and may be used to predict progression from early to late stage MPN.

• Klíčová slova
• CD34, Gene expression, JAK2V617F, MPN,
• MeSH
• antigeny CD34 genetika   MeSH
• esenciální trombocytemie genetika   MeSH
• lidé MeSH
• myeloproliferativní poruchy genetika   MeSH
• polycythaemia vera genetika   MeSH
• primární myelofibróza genetika   MeSH
• regulace genové exprese u nádorů MeSH
• transkriptom * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antigeny CD34 MeSH

We studied a subset of hematopoietic stem cells (HSCs) that are defined by elevated expression of CD41 (CD41hi) and showed bias for differentiation toward megakaryocytes (Mks). Mouse models of myeloproliferative neoplasms (MPNs) expressing JAK2-V617F (VF) displayed increased frequencies and percentages of the CD41hi vs CD41lo HSCs compared with wild-type controls. An increase in CD41hi HSCs that correlated with JAK2-V617F mutant allele burden was also found in bone marrow from patients with MPN. CD41hi HSCs produced a higher number of Mk-colonies of HSCs in single-cell cultures in vitro, but showed reduced long-term reconstitution potential compared with CD41lo HSCs in competitive transplantations in vivo. RNA expression profiling showed an upregulated cell cycle, Myc, and oxidative phosphorylation gene signatures in CD41hi HSCs, whereas CD41lo HSCs showed higher gene expression of interferon and the JAK/STAT and TNFα/NFκB signaling pathways. Higher cell cycle activity and elevated levels of reactive oxygen species were confirmed in CD41hi HSCs by flow cytometry. Expression of Epcr, a marker for quiescent HSCs inversely correlated with expression of CD41 in mice, but did not show such reciprocal expression pattern in patients with MPN. Treatment with interferon-α further increased the frequency and percentage of CD41hi HSCs and reduced the number of JAK2-V617F+ HSCs in mice and patients with MPN. The shift toward the CD41hi subset of HSCs by interferon-α provides a possible mechanism of how interferon-α preferentially targets the JAK2 mutant clone.

• MeSH
• bodová mutace účinky léků   MeSH
• genový knockin MeSH
• hematopoetické kmenové buňky cytologie   metabolismus   MeSH
• interferon alfa terapeutické užití   MeSH
• Janus kinasa 2 genetika   MeSH
• lidé MeSH
• megakaryocyty cytologie   metabolismus   MeSH
• myeloproliferativní poruchy farmakoterapie   genetika   MeSH
• myši transgenní MeSH
• myši MeSH
• trombocytový membránový glykoprotein IIb genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• interferon alfa MeSH
• JAK2 protein, human MeSH Prohlížeč
• Jak2 protein, mouse MeSH Prohlížeč
• Janus kinasa 2 MeSH
• trombocytový membránový glykoprotein IIb MeSH

Here we describe the major genetic and genomic aberrations found in myeloid malignancies and how those markers are used in patients' diagnosis, prognosis, and targeted treatment. In Bosnia and Herzegovina, cytogenetic and molecular diagnostics for myeloid malignancies have been established and continually improved since 2005. We report the current state of available diagnostic tools for myeloid malignancies in Bosnia and Herzegovina. Myeloid malignancies are a heterogeneous group of clonal blood diseases characterized by defects in hematopoietic stem cells and myeloid progenitors that lead to abnormal proliferation, differentiation, localization, and self-renewal. Most common myeloid malignancies include myeloproliferative neoplasms (MPNs), myelodysplastic syndrome (MDS), and acute myeloid leukemia (AML). Molecular diagnostics of myeloid malignancies have significantly expanded in the last decade with new genetic and genomic markers for diagnosis, prognosis, and treatment. CONCLUSION: In the last decade, several new genomic markers important for patient diagnosis, prognosis, and therapy have been discovered that need to be implemented in routine molecular diagnostics not only in developed nations but also in developing nations such as Bosnia and Herzegovina.

• Klíčová slova
• Acute Myeloid Leukemia, Molecular Diagnostics, Myelodysplastic Syndrome, Myeloid Neoplasms, Myeloproliferative Neoplasms,
• MeSH
• akutní myeloidní leukemie * diagnóza   genetika   MeSH
• lidé MeSH
• myelodysplastické syndromy * diagnóza   genetika   MeSH
• myeloproliferativní poruchy * diagnóza   genetika   MeSH
• prognóza MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Geografické názvy
• Bosna a Hercegovina MeSH

Arterial thrombosis is a common complication in patients with Ph- myeloproliferative neoplasms (MPN). We searched for the risk factors of stroke in MPN patients from anagrelide registry. We analyzed the potential risk factors triggering a stroke/TIA event in 249 MPN patients with previous stroke (n = 168) or Transient Ischemic Attack (TIA) (n = 140), and in 1,193 MPN control subjects (without clinical history of thrombosis). These patients were registered in a prospective manner, providing a follow-up period after Anagrelide treatment. The median age of the patients in the experimental group was of 56 years of age (ranging from 34-76) and of 53 years of age (ranging from 26-74) in the control group (p < 0.001). Using a multivariate model, we determined the following as risk factors: JAK2V617F mutation (OR 2.106, 1.458-3.043, p = 0.006), age (OR 1.017/year, 1.005-1,029, p = 0.006), male gender (OR 1.419, 1.057-1.903, p = 0.020), MPN diagnosis (OR for PMF 0.649, 0.446-0.944, p = 0.024), BMI (OR 0.687 for BMI > 25, 0.473-0.999, p = 0.05) and high TAG levels (OR 1.734, 1.162-2.586, p = 0.008), all of which were statistically significant for CMP development. Concerning the risk factors for thrombophilia, only the antiphospholipid syndrome (OR 1.994, 1.017-3.91, p = 0.048) was noteworthy in a stroke-relevant context. There was no significant difference between the blood count of the patients prior to a stroke event and the control group, both of which were under a cytoreductive treatment. We found that age, male gender, JAK2V617F mutation, previous venous thrombosis, and hypertriglyceridemia represent independent risk factors for the occurrence of a stroke in Ph- MPN patients.

• Klíčová slova
• JAK2, Myeloproliferation, Risk factor, Stroke, TIA, Thrombosis,
• MeSH
• cévní mozková příhoda etiologie   MeSH
• chinazoliny terapeutické užití   MeSH
• dospělí MeSH
• fibrinolytika terapeutické užití   MeSH
• Janus kinasa 2 genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• myeloproliferativní poruchy komplikace   genetika   MeSH
• rizikové faktory MeSH
• senioři MeSH
• trombóza etiologie   prevence a kontrola   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• anagrelide MeSH Prohlížeč
• chinazoliny MeSH
• fibrinolytika MeSH
• JAK2 protein, human MeSH Prohlížeč
• Janus kinasa 2 MeSH

Myeloproliferative neoplasms (MPN) are genetically very complex and heterogeneous diseases in which the acquisition of a somatic driver mutation triggers three main myeloid cytokine receptors, and phenotypically expresses as polycythemia vera (PV), essential thrombocytosis (ET), and primary myelofibrosis (PMF). The course of the diseases may be influenced by germline predispositions, modifying mutations, their order of acquisition and environmental factors such as aging and inflammation. Deciphering these contributory elements, their mutual interrelationships, and their contribution to MPN pathogenesis brings important insights into the diseases. Animal models (mainly mouse and zebrafish) have already significantly contributed to understanding the role of several acquired and germline mutations in MPN oncogenic signaling. Novel technologies such as induced pluripotent stem cells (iPSCs) and precise genome editing (using CRISPR/Cas9) contribute to the emerging understanding of MPN pathogenesis and clonal architecture, and form a convenient platform for evaluating drug efficacy. In this overview, the genetic landscape of MPN is briefly described, with an attempt to cover the main discoveries of the last 15 years. Mouse and zebrafish models of the driver mutations are discussed and followed by a review of recent progress in modeling MPN with patient-derived iPSCs and CRISPR/Cas9 gene editing.

• Klíčová slova
• CALR, JAK2, MPL, MPN (myeloproliferative neoplasms), iPSCs, mice, thrombosis, zebrafish,
• MeSH
• dánio pruhované MeSH
• esenciální trombocytemie genetika   MeSH
• fenotyp MeSH
• indukované pluripotentní kmenové buňky metabolismus   MeSH
• Janus kinasa 2 genetika   MeSH
• kalretikulin genetika   MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• mutace MeSH
• myeloproliferativní poruchy genetika   patofyziologie   MeSH
• myši MeSH
• nádory genetika   MeSH
• polycythaemia vera genetika   MeSH
• primární myelofibróza genetika   MeSH
• receptory thrombopoetinu genetika   MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• Janus kinasa 2 MeSH
• kalretikulin MeSH
• receptory thrombopoetinu MeSH

BACKGROUND: Microparticles (MPs) are small (0.1-1 μm) cell-derived vesicles released during activation or apoptosis, with a surface-exposed phosphatidylserine along with antigens indicating the cellular origin. The level of MPs is known to be elevated in thromboembolic diseases and malignancies; it is believed that MPs are not only amplifying but can also initiate the thrombogenesis processes. BCR/ABL negative myeloproliferative neoplasms (MPNs) are clonal haematopoietic diseases, which include polycythemia vera, essential thrombocythemia and primary myelofibrosis. One of the main problems of MPN patients is high risk and incidence of thrombosis which affect the survival, quality of life and life expectancy. PATIENTS AND METHODS: The clinical significance of circulating MPs was assessed in a group of 179 patients with BCR/ABL-negative MPNs. Analysis of MPs was done using flow cytometry on 417 samples, and MPs procoagulation activity was performed using a functional assay called Zymuphen MP-activity (Hyphen Biomed, Neuville-sur-oise, France) on 274 samples. RESULTS: Significantly higher absolute and relative count of platelet MPs was found in MPN patients when compared with healthy group, respectively (p = 0.001, p = 0.043). Erythrocyte MPs were also significantly higher in MPN patients than in the healthy group (p < 0.001). Procoagulation activity of MPs was as well significantly higher in patients compared to the control group (p < 0.001). Patients with primary myelofibrosis had decreased absolute and relative count of platelet MPs compared to polycythemia vera and essential thrombocythemia patients, respectively (p = 0.008, p = 0.014). Presence of JAK2V617F mutation was associated with higher absolute and relative count of platelet MPs, respectively (p = 0.045, p = 0.029). CONCLUSION: Although some literature data support the hypothesis of a direct relation between MPs and thrombotic events in MPN patients, further studies are needed to evaluate the clinical implication of MPs in the hypercoagulation state of MPN patients.

• Klíčová slova
• Janus Kinase 2, microparticles, myeloproliferative disorders, procoagulation activity, thrombosis,
• MeSH
• bcr-abl fúzové proteiny genetika   MeSH
• dospělí MeSH
• kvalita života * MeSH
• lidé středního věku MeSH
• lidé MeSH
• mikropartikule metabolismus   patologie   MeSH
• myeloproliferativní poruchy komplikace   genetika   MeSH
• nádorové biomarkery krev   MeSH
• následné studie MeSH
• pilotní projekty MeSH
• studie případů a kontrol MeSH
• trombóza krev   diagnóza   etiologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bcr-abl fúzové proteiny MeSH
• nádorové biomarkery MeSH