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SEBASTIANO RONTAUROLI

Ricercatore t.d. art. 24 c. 3 lett. A
Dipartimento di Scienze Biomediche, Metaboliche e Neuroscienze - sede Centro di Medicina Rigenerativa S.Ferrari

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Pubblicazioni

2023 - Chromosome 9p Duplication Promotes T-Cell Exhaustion and Enhances Stem Cell Clonogenic Potential in JAK2-Mutant Myeloproliferative Neoplasms [Abstract in Rivista]
Norfo, Ruggiero; Carretta, Chiara; Parenti, Sandra; Badii, Filippo; Bertesi, Matteo; Rontauroli, Sebastiano; Tavernari, Lara; Genovese, Elena; Sperduti, Samantha; Enzo, Elena; Mirabile, Margherita; Pedrazzi, Francesca; Pessina, Chiara; Colugnat, Ilaria; Mora, Barbara; Maccaferri, Monica; Tenedini, Elena; Martinelli, Silvia; Bianchi, Elisa; Casarini, Livio; Potenza, Leonardo; Luppi, Mario; Tagliafico, Enrico; Guglielmelli, Paola; Simoni, Manuela; Passamonti, Francesco; Vannucchi, Alessandro Maria; Manfredini, Rossella
abstract

2023 - Inhibition of ERK1/2 signaling prevents bone marrow fibrosis by reducing osteopontin plasma levels in a myelofibrosis mouse model [Articolo su rivista]
Bianchi, Elisa; Rontauroli, Sebastiano; Tavernari, Lara; Mirabile, Margherita; Pedrazzi, Francesca; Genovese, Elena; Sartini, Stefano; Dall'Ora, Massimiliano; Grisendi, Giulia; Fabbiani, Luca; Maccaferri, Monica; Carretta, Chiara; Parenti, Sandra; Fantini, Sebastian; Bartalucci, Niccolò; Calabresi, Laura; Balliu, Manjola; Guglielmelli, Paola; Potenza, Leonardo; Tagliafico, Enrico; Losi, Lorena; Dominici, Massimo; Luppi, Mario; Vannucchi, Alessandro Maria; Manfredini, Rossella
abstract

Clonal myeloproliferation and development of bone marrow (BM) fibrosis are the major pathogenetic events in myelofibrosis (MF). The identification of novel antifibrotic strategies is of utmost importance since the effectiveness of current therapies in reverting BM fibrosis is debated. We previously demonstrated that osteopontin (OPN) has a profibrotic role in MF by promoting mesenchymal stromal cells proliferation and collagen production. Moreover, increased plasma OPN correlated with higher BM fibrosis grade and inferior overall survival in MF patients. To understand whether OPN is a druggable target in MF, we assessed putative inhibitors of OPN expression in vitro and identified ERK1/2 as a major regulator of OPN production. Increased OPN plasma levels were associated with BM fibrosis development in the Romiplostim-induced MF mouse model. Moreover, ERK1/2 inhibition led to a remarkable reduction of OPN production and BM fibrosis in Romiplostim-treated mice. Strikingly, the antifibrotic effect of ERK1/2 inhibition can be mainly ascribed to the reduced OPN production since it could be recapitulated through the administration of anti-OPN neutralizing antibody. Our results demonstrate that OPN is a novel druggable target in MF and pave the way to antifibrotic therapies based on the inhibition of ERK1/2-driven OPN production or the neutralization of OPN activity.

2022 - Novel Molecular Insights into Leukemic Evolution of Myeloproliferative Neoplasms: A Single Cell Perspective [Articolo su rivista]
Rontauroli, Sebastiano; Carretta, Chiara; Parenti, Sandra; Bertesi, Matteo; Manfredini, Rossella
abstract

Myeloproliferative neoplasms (MPNs) are clonal disorders originated by the serial acquisition of somatic mutations in hematopoietic stem/progenitor cells. The major clinical entities are represented by polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), that are caused by driver mutations affecting JAK2, MPL or CALR. Disease progression is related to molecular and clonal evolution. PV and ET can progress to secondary myelofibrosis (sMF) but can also evolve to secondary acute myeloid leukemia (sAML). PMF is associated with the highest frequency of leukemic transformation, which represents the main cause of death. sAML is associated with a dismal prognosis and clinical features that differ from those of de novo AML. The molecular landscape distinguishes sAML from de novo AML, since the most frequent hits involve TP53, epigenetic regulators, spliceosome modulators or signal transduction genes. Single cell genomic studies provide novel and accurate information about clonal architecture and mutation acquisition order, allowing the reconstruction of clonal dynamics and molecular events that accompany leukemic transformation. In this review, we examine our current understanding of the genomic heterogeneity in MPNs and how it affects disease progression and leukemic transformation. We focus on molecular events elicited by somatic mutations acquisition and discuss the emerging findings coming from single cell studies.

2022 - The Response to Oxidative Damage Correlates with Driver Mutations and Clinical Outcome in Patients with Myelofibrosis [Articolo su rivista]
Genovese, E.; Mirabile, M.; Rontauroli, S.; Sartini, S.; Fantini, S.; Tavernari, L.; Maccaferri, M.; Guglielmelli, P.; Bianchi, E.; Parenti, S.; Carretta, C.; Mallia, S.; Castellano, S.; Colasante, C.; Balliu, M.; Bartalucci, N.; Palmieri, R.; Ottone, T.; Mora, B.; Potenza, L.; Passamonti, F.; Voso, M. T.; Luppi, M.; Vannucchi, A. M.; Tagliafico, E.; Manfredini, R.
abstract

Myelofibrosis (MF) is the Philadelphia-negative myeloproliferative neoplasm characterized by the worst prognosis and no response to conventional therapy. Driver mutations in JAK2 and CALR impact on JAK-STAT pathway activation but also on the production of reactive oxygen species (ROS). ROS play a pivotal role in inflammation-induced oxidative damage to cellular components including DNA, therefore leading to greater genomic instability and promoting cell transformation. In order to unveil the role of driver mutations in oxidative stress, we assessed ROS levels in CD34+ hematopoietic stem/progenitor cells of MF patients. Our results demonstrated that ROS production in CD34+ cells from CALR-mutated MF patients is far greater compared with patients harboring JAK2 mutation, and this leads to increased oxidative DNA damage. Moreover, CALR-mutant cells show less superoxide dismutase (SOD) antioxidant activity than JAK2-mutated ones. Here, we show that high plasma levels of total antioxidant capacity (TAC) correlate with detrimental clinical features, such as high levels of lactate dehydrogenase (LDH) and circulating CD34+ cells. Moreover, in JAK2-mutated patients, high plasma level of TAC is also associated with a poor overall survival (OS), and multivariate analysis demonstrated that high TAC classification is an independent prognostic factor allowing the identification of patients with inferior OS in both DIPSS lowest and highest categories. Altogether, our data suggest that a different capability to respond to oxidative stress can be one of the mechanisms underlying disease progression of myelofibrosis.

2021 - Gene expression profile correlates with molecular and clinical features in patients with myelofibrosis [Articolo su rivista]
Rontauroli, S.; Castellano, S.; Guglielmelli, P.; Zini, R.; Bianchi, E.; Genovese, E.; Carretta, C.; Parenti, S.; Fantini, S.; Mallia, S.; Tavernari, L.; Sartini, S.; Mirabile, M.; Mannarelli, C.; Gesullo, F.; Pacilli, A.; Pietra, D.; Rumi, E.; Salmoiraghi, S.; Mora, B.; Villani, L.; Grilli, A.; Rosti, V.; Barosi, G.; Passamonti, F.; Rambaldi, A.; Malcovati, L.; Cazzola, M.; Bicciato, S.; Tagliafico, E.; Vannucchi, A. M.; Manfredini, R.
abstract

Myelofibrosis (MF) belongs to the family of classic Philadelphia-negative myeloproliferative neoplasms (MPNs). It can be primary myelofibrosis (PMF) or secondary myelofibrosis (SMF) evolving from polycythemia vera (PV) or essential thrombocythemia (ET). Despite the differences, PMF and SMF patients are currently managed in the same way, and prediction of survival is based on the same clinical and genetic features. In the last few years, interest has grown concerning the ability of gene expression profiles (GEPs) to provide valuable prognostic information. Here, we studied the GEPs of granulocytes from 114 patients with MF, using a microarray platform to identify correlations with patient characteristics and outcomes. Cox regression analysis led to the identification of 201 survival-related transcripts characterizing patients who are at high risk for death. High-risk patients identified by this gene signature displayed an inferior overall survival and leukemia-free survival, together with clinical and molecular detrimental features included in contemporary prognostic models, such as the presence of high molecular risk mutations. The high-risk group was enriched in post-PV and post-ET MF and JAK2V617F homozygous patients, whereas pre-PMF was more frequent in the low-risk group. These results demonstrate that GEPs in MF patients correlate with their molecular and clinical features, particularly their survival, and represent the proof of concept that GEPs might provide complementary prognostic information to be applied in clinical decision making.

2021 - Increased Plasma Levels of lncRNAs LINC01268, GAS5 and MALAT1 Correlate with Negative Prognostic Factors in Myelofibrosis [Articolo su rivista]
Fantini, Sebastian; Rontauroli, Sebastiano; Sartini, Stefano; Mirabile, Margherita; Bianchi, Elisa; Badii, Filippo; Maccaferri, Monica; Guglielmelli, Paola; Ottone, Tiziana; Palmieri, Raffaele; Genovese, Elena; Carretta, Chiara; Parenti, Sandra; Mallia, Selene; Tavernari, Lara; Salvadori, Costanza; Gesullo, Francesca; Maccari, Chiara; Zizza, Michela; Grande, Alexis; Salmoiraghi, Silvia; Mora, Barbara; Potenza, Leonardo; Rosti, Vittorio; Passamonti, Francesco; Rambaldi, Alessandro; Voso, Maria Teresa; Mecucci, Cristina; Tagliafico, Enrico; Luppi, Mario; Vannucchi, Alessandro Maria; Manfredini, Rossella
abstract

: Long non-coding RNAs (lncRNAs) have been recently described as key mediators in the development of hematological malignancies. In the last years, circulating lncRNAs have been proposed as a new class of non-invasive biomarkers for cancer diagnosis and prognosis and to predict treatment response. The present study is aimed to investigate the potential of circulating lncRNAs as non-invasive prognostic biomarkers in myelofibrosis (MF), the most severe among Philadelphia-negative myeloproliferative neoplasms. We detected increased levels of seven circulating lncRNAs in plasma samples of MF patients (n = 143), compared to healthy controls (n = 65). Among these, high levels of LINC01268, MALAT1 or GAS5 correlate with detrimental clinical variables, such as high count of leukocytes and CD34+ cells, severe grade of bone marrow fibrosis and presence of splenomegaly. Strikingly, high plasma levels of LINC01268 (p = 0.0018), GAS5 (p = 0.0008) or MALAT1 (p = 0.0348) are also associated with a poor overall-survival while high levels of LINC01268 correlate with a shorter leukemia-free-survival. Finally, multivariate analysis demonstrated that the plasma level of LINC01268 is an independent prognostic variable, suggesting that, if confirmed in future in an independent patients' cohort, it could be used for further studies to design an updated classification model for MF patients.

2021 - Mutated clones driving leukemic transformation are already detectable at the single-cell level in CD34-positive cells in the chronic phase of primary myelofibrosis [Articolo su rivista]
Parenti, Sandra; Rontauroli, Sebastiano; Carretta, Chiara; Mallia, Selene; Genovese, Elena; Chiereghin, Chiara; Peano, Clelia; Tavernari, Lara; Bianchi, Elisa; Fantini, Sebastian; Sartini, Stefano; Romano, Oriana; Bicciato, Silvio; Tagliafico, Enrico; Della Porta, Matteo; Manfredini, Rossella
abstract

Disease progression of myeloproliferative neoplasms is the result of increased genomic complexity. Since the ability to predict disease evolution is crucial for clinical decisions, we studied single-cell genomics and transcriptomics of CD34-positive cells from a primary myelofibrosis (PMF) patient who progressed to acute myeloid leukemia (AML) while receiving Ruxolitinib. Single-cell genomics allowed the reconstruction of clonal hierarchy and demonstrated that TET2 was the first mutated gene while FLT3 was the last one. Disease evolution was accompanied by increased clonal heterogeneity and mutational rate, but clones carrying TP53 and FLT3 mutations were already present in the chronic phase. Single-cell transcriptomics unraveled repression of interferon signaling suggesting an immunosuppressive effect exerted by Ruxolitinib. Moreover, AML transformation was associated with a differentiative block and immune escape. These results suggest that single-cell analysis can unmask tumor heterogeneity and provide meaningful insights about PMF progression that might guide personalized therapy.

2020 - Genomic analysis of hematopoietic stem cell at the single-cell level: Optimization of cell fixation and whole genome amplification (WGA) protocol [Articolo su rivista]
Carretta, C.; Mallia, S.; Genovese, E.; Parenti, S.; Rontauroli, S.; Bianchi, E.; Fantini, S.; Sartini, S.; Tavernari, L.; Tagliafico, E.; Manfredini, R.
abstract

Single-cell genomics has become the method of choice for the study of heterogeneous cell populations and represents an elective application in defining the architecture and clonal evolution in hematological neoplasms. Reconstructing the clonal evolution of a neoplastic population therefore represents the main way to understand more deeply the pathogenesis of the neoplasm, but it is also a potential tool to understand the evolution of the tumor population with respect to its response to therapy. Pre-analytical phase for single-cell genomics analysis is crucial to obtain a cell population suitable for single-cell sorting, and whole genome amplification is required to obtain the necessary amount of DNA from a single cell in order to proceed with sequencing. Here, we evaluated the impact of different methods of cellular immunostaining, fixation and whole genome amplification on the efficiency and yield of single-cell sequencing.

2019 - Calreticulin Ins5 and Del52 mutations impair unfolded protein and oxidative stress responses in K562 cells expressing CALR mutants [Articolo su rivista]
Salati, Simona; Genovese, Elena; Carretta, Chiara; Zini, Roberta; Bartalucci, Niccolò; Prudente, Zelia; Pennucci, Valentina; Ruberti, Samantha; Rossi, Chiara; Rontauroli, Sebastiano; Enzo, Elena; Calabresi, Laura; Balliu, Manjola; Mannarelli, Carmela; Bianchi, Elisa; Guglielmelli, Paola; Tagliafico, Enrico; Vannucchi, Alessandro M; Manfredini, Rossella
abstract

Somatic mutations of calreticulin (CALR) have been described in approximately 60-80% of JAK2 and MPL unmutated Essential Thrombocythemia and Primary Myelofibrosis patients. CALR is an endoplasmic reticulum (ER) chaperone responsible for proper protein folding and calcium retention. Recent data demonstrated that the TPO receptor (MPL) is essential for the development of CALR mutant-driven Myeloproliferative Neoplasms (MPNs). However, the precise mechanism of action of CALR mutants haven't been fully unraveled. In this study, we showed that CALR mutants impair the ability to respond to the ER stress and reduce the activation of the pro-apoptotic pathway of the unfolded protein response (UPR). Moreover, our data demonstrated that CALR mutations induce increased sensitivity to oxidative stress, leading to increase oxidative DNA damage. We finally demonstrated that the downmodulation of OXR1 in CALR-mutated cells could be one of the molecular mechanisms responsible for the increased sensitivity to oxidative stress mediated by mutant CALR. Altogether, our data identify novel mechanisms collaborating with MPL activation in CALR-mediated cellular transformation. CALR mutants negatively impact on the capability of cells to respond to oxidative stress leading to genomic instability and on the ability to react to ER stress, causing resistance to UPR-induced apoptosis.

2018 - Calreticulin affects hematopoietic stem/progenitor cell fate by impacting erythroid and megakaryocytic differentiation [Articolo su rivista]
Salati, Simona; Prudente, Zelia; Genovese, Elena; Pennucci, Valentina; Rontauroli, Sebastiano; Bartalucci, Niccolo'; Mannarelli, Carmela; Ruberti, Samantha; Zini, Roberta; Rossi, Chiara; Bianchi, Elisa; Guglielmelli, Paola; Tagliafico, Enrico; Vannucchi, Alessandro M; Manfredini, Rossella
abstract

Calreticulin (CALR) is a chaperone protein that localizes primarily to the endoplasmic reticulum (ER) lumen where it is responsible for the control of proper folding of neo-synthesized glycoproteins and for the retention of calcium. Recently, mutations affecting exon 9 of the CALR gene have been described in approximately 40% of patients with myeloproliferative neoplasms (MPNs). Although the role of mutated CALR in the development of MPNs has begun to be clarified, there are still no data available on the function of wild-type (WT) CALR during physiological hematopoiesis. In order to shed light on the role of WT CALR during normal hematopoiesis, we performed gene silencing and overexpression experiments in Hematopoietic Stem Progenitor Cells (HSPCs). Our results showed that CALR overexpression is able to affect physiological hematopoiesis by enhancing both erythroid and megakaryocytic (MK) differentiation. In agreement with overexpression data, CALR silencing caused a significant decrease in both erythroid and MK differentiation of human HSPCs. Gene expression profiling (GEP) analysis showed that CALR is able to affect the expression of several genes involved in HSPCs differentiation towards both the erythroid and MK lineages. Moreover, GEP data also highlighted the modulation of several genes involved in ER stress response, unfolded protein response (UPR), DNA repair and of several genes already described to play a role in MPN development, such as pro-inflammatory cytokines and hematological neoplasms-related markers. Altogether, our data unraveled a new and unexpected role for CALR in the regulation of normal hematopoietic differentiation. Moreover, by showing the impact of CALR on the expression of genes involved in several biological processes already described in cellular transformation, our data strongly suggest a more complex role for CALR in MPN development that goes beyond the activation of the THPO receptor and involves ER stress response, UPR and DNA repair.

2018 - Involvement of MAF/SPP1 axis in the development of bone marrow fibrosis in PMF patients [Articolo su rivista]
Ruberti, S; Bianchi, E; Guglielmelli, P; Rontauroli, S; Barbieri, G; Tavernari, L; Fanelli, T; Norfo, R; Pennucci, V; Fattori, G. Corbizi; Mannarelli, C; Bartalucci, N; Mora, B; Elli, L; Avanzini, M. A; Rossi, C; Salmoiraghi, S; Zini, R; Salati, S; Prudente, Z; Rosti, V; Passamonti, F; Rambaldi, A; Ferrari, S; Tagliafico, E; Vannucchi, A. M; Manfredini, R.
abstract

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by hyperplastic megakaryopoiesis and myelofibrosis. We recently described the upregulation of MAF (v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog) in PMF CD34+ hematopoietic progenitor cells (HPCs) compared to healthy donor. Here we demonstrated that MAF is also upregulated in PMF compared with the essential thrombocytemia (ET) and polycytemia vera (PV) HPCs. MAF overexpression and knockdown experiments shed some light into the role of MAF in PMF pathogenesis, by demonstrating that MAF favors the megakaryocyte and monocyte/macrophage commitment of HPCs and leads to the increased expression of proinflammatory and profibrotic mediators. Among them, we focused our further studies on SPP1 and LGALS3. We assessed SPP1 and LGALS3 protein levels in 115 PMF, 47 ET and 24 PV patients plasma samples and we found that SPP1 plasma levels are significantly higher in PMF compared with ET and PV patients. Furthermore, in vitro assays demonstrated that SPP1 promotes fibroblasts and mesenchymal stromal cells proliferation and collagen production. Strikingly, clinical correlation analyses uncovered that higher SPP1 plasma levels in PMF patients correlate with a more severe fibrosis degree and a shorter overall survival. Collectively our data unveil that MAF overexpression contributes to PMF pathogenesis by driving the deranged production of the profibrotic mediator SPP1.

2018 - Role of TGF-β1/miR-382-5p/SOD2 axis in the induction of oxidative stress in CD34+ cells from primary myelofibrosis [Articolo su rivista]
Rossi, Chiara; Zini, Roberta; Rontauroli, Sebastiano; Ruberti, Samantha; Prudente, Zelia; Barbieri, Greta; Bianchi, Elisa; Salati, Simona; Genovese, Elena; Bartalucci, Niccolò; Guglielmelli, Paola; Tagliafico, Enrico; Rosti, Vittorio; Barosi, Giovanni; Vannucchi, Alessandro M.; Manfredini, Rossella
abstract

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by an excessive production of pro-inflammatory cytokines resulting in chronic inflammation and genomic instability. Besides the driver mutations in JAK2, MPL, and CALR genes, the deregulation of miRNA expression may also contribute to the pathogenesis of PMF. To this end, we recently reported the upregulation of miR-382-5p in PMF CD34+ cells. In order to unveil the mechanistic details of the role of miR-382-5p in pathogenesis of PMF, we performed gene expression profiling of CD34+ cells overexpressing miR-382-5p. Among the downregulated genes, we identified superoxide dismutase 2 (SOD2), which is a predicted target of miR-382-5p. Subsequently, we confirmed miR-382-5p/SOD2 interaction by luciferase assay and we showed that miR-382-5p overexpression in CD34+ cells causes the decrease in SOD2 activity leading to reactive oxygen species (ROS) accumulation and oxidative DNA damage. In addition, our data indicate that inhibition of miR-382-5p in PMF CD34+ cells restores SOD2 function, induces ROS disposal, and reduces DNA oxidation. Since the pro-inflammatory cytokine transforming growth factor-β1 (TGF-β1) is a key player in PMF pathogenesis, we further investigated the effect of TGF-β1 on ROS and miR-382-5p levels. Our data showed that TGF-β1 treatment enhances miR-382-5p expression and reduces SOD2 activity leading to ROS accumulation. Finally, inhibition of TGF-β1 signaling in PMF CD34+ cells by galunisertib significantly reduced miR-382-5p expression and ROS accumulation and restored SOD2 activity. As a whole, this study reports that TGF-β1/miR-382-5p/SOD2 axis deregulation in PMF cells is linked to ROS overproduction that may contribute to enhanced oxidative stress and inflammation. Our results suggest that galunisertib may represent an effective drug reducing abnormal oxidative stress induced by TGF-β1 in PMF patients. Database linking: GEO: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE103464.

2017 - CALR mutational status identifies different disease subtypes of essential thrombocythemia showing distinct expression profiles [Articolo su rivista]
Zini, Roberta; Guglielmelli, Paola; Pietra, Daniela; Rumi, Elisa; Rossi, Chiara; Rontauroli, Sebastiano; Genovese, Elena; Fanelli, Tiziana; Calabresi, Laura; Bianchi, Elisa; Salati, Simona; Cazzola, Mario; Tagliafico, Enrico; Vannucchi, Alessandro M.; Manfredini, Rossella
abstract

Polycythemia vera (PV) and essential thrombocythemia (ET) are Philadelphia-negative myeloproliferative neoplasms (MPNs) characterized by erythrocytosis and thrombocytosis, respectively. Approximately 95% of PV and 50-70% of ET patients harbor the V617F mutation in the exon 14 of JAK2 gene, while about 20-30% of ET patients carry CALRins5 or CALRdel52 mutations. These ET CALR-mutated subjects show higher platelet count and lower thrombotic risk compared to JAK2-mutated patients. Here, we showed that CALR-mutated and JAK2V617F-positive CD34+ cells display different gene and miRNA expression profiles. Indeed, we highlighted several pathways differentially activated between JAK2V617F- and CALR-mutated progenitors, i.e., mTOR, MAPK/PI3K, and MYC pathways. Furthermore, we unveiled that the expression of several genes involved in DNA repair, chromatin remodeling, splicing, and chromatid cohesion are decreased in CALR-mutated cells. According to the low risk of thrombosis in CALR-mutated patients, we also found the downregulation of several genes involved in thrombin signaling and platelet activation. As a whole, these data support the model that CALR-mutated ET could be considered as a distinct disease entity from JAK2V617F-positive MPNs and may provide the molecular basis supporting the different clinical features of these patients.

2017 - Deregulated expression of miR-29a-3p, miR-494-3p and miR-660-5p affects sensitivity to tyrosine kinase inhibitors in CML leukemic stem cells [Articolo su rivista]
Salati, Simona; Salvestrini, Valentina; Carretta, Chiara; Genovese, Elena; Rontauroli, Sebastiano; Zini, Roberta; Rossi, Chiara; Ruberti, Samantha; Bianchi, Elisa; Barbieri, Greta; Curti, Antonio; Castagnetti, Fausto; Gugliotta, Gabriele; Rosti, Gianantonio; Bergamaschi, Micaela; Tafuri, Agostino; Tagliafico, Enrico; Lemoli, Roberto; Manfredini, Rossella
abstract

The development of Imatinib mesylate (IM), which targets the oncogenic BCRABL fusion protein, has greatly improved the outcome of Chronic Myeloid Leukemia (CML) patients. However, BCR-ABL-positive progenitors can be detected in CML patients in complete cytogenetic response. Several evidence suggests that CML stem cells are intrinsically resistant to Tyrosine Kinase Inhibitors (TKI), and therefore they represent the most likely candidate responsible for disease relapse. In this work, we investigated the microRNA (miRNA) expression profile of different subpopulations of CML Leukemic Stem Cells (LSCs): Lin-CD34+CD38-and Lin-CD34-CD38-cells. These cell fractions have been previously shown to be endowed with TKI intrinsic resistance. Our analysis identified 33 common deregulated miRNAs in CML LSCs. Among those, 8 miRNAs were deregulated in CML independently from BCR-ABL kinase activity and therefore are likely to be involved in the BCR-ABL-independent resistance to TKI that characterizes CML LSCs. In particular, the up-regulation of miR-29a-3p and miR-660-5p observed in CML LSCs, led to the down-regulation of their respective targets TET2 and EPAS1 and conferred TKI-resistance to CML LSCs in vitro. On the other hand, miR-494-3p down-regulation in CML LSCs, leading to c-MYC up-regulation, was able to decrease TKI-induced apoptosis. These results demonstrate that aberrant miRNA expression in CML LSCs could contribute to the intrinsic TKIresistance observed in these cell populations, and support the development of novel therapies aimed at targeting aberrantly regulated miRNAs or their targets in order to effectively eradicate CML LSCs.

2017 - miR-494-3p overexpression promotes megakaryocytopoiesis in primary myelofibrosis hematopoietic stem/progenitor cells by targeting SOCS6 [Articolo su rivista]
Rontauroli, Sebastiano; Norfo, Ruggiero; Pennucci, Valentina; Zini, Roberta; Ruberti, Samantha; Bianchi, Elisa; Salati, Simona; Prudente, Zelia; Rossi, Chiara; Rosti, Vittorio; Guglielmelli, Paola; Barosi, Giovanni; Vannucchi, Alessandro; Tagliafico, Enrico; Manfredini, Rossella
abstract

Primary myelofibrosis (PMF) is a chronic Philadelphia-negative myeloproliferative neoplasm characterized by hematopoietic stem cell-derived clonal myeloproliferation, involving especially the megakaryocyte lineage. To better characterize how the altered expression of microRNAs might contribute to PMF pathogenesis, we have previously performed the integrative analysis of gene and microRNA expression profiles of PMF hematopoietic stem/progenitor cells (HSPCs), which allowed us to identify miR- 494-3p as the upregulated microRNA predicted to target the highest number of downregulated mRNAs. To elucidate the role of miR-494-3p in hematopoietic differentiation, in the present study we demonstrated that miR-494-3p enforced expression in normal HSPCs promotes megakaryocytopoiesis. Gene expression profiling upon miR-494-3p overexpression allowed the identification of genes commonly downregulated both after microRNA overexpression and in PMF CD34+ cells. Among them, suppressor of cytokine signaling 6 (SOCS6) was confirmed to be a miR-494-3p target by luciferase assay. Western blot analysis showed reduced level of SOCS6 protein as well as STAT3 activation in miR-494-3p overexpressing cells. Furthermore, transient inhibition of SOCS6 expression in HSPCs demonstrated that SOCS6 silencing stimulates megakaryocytopoiesis, mimicking the phenotypic effects observed upon miR-494-3p overexpression. Finally, to disclose the contribution of miR-494-3p upregulation to PMF pathogenesis, we performed inhibition experiments in PMF HSPCs, which showed that miR-494-3p silencing led to SOCS6 upregulation and impaired megakaryocyte differentiation. Taken together, our results describe for the first time the role of miR-494- 3p during normal HSPC differentiation and suggest that its increased expression, and the subsequent downregulation of its target SOCS6, might contribute to the megakaryocyte hyperplasia commonly observed in PMF patients.

2017 - Role of miR-34a-5p in Hematopoietic Progenitor Cells Proliferation and Fate Decision: Novel Insights into the Pathogenesis of Primary Myelofibrosis [Articolo su rivista]
Bianchi, Elisa; Ruberti, Samantha; Rontauroli, Sebastiano; Guglielmelli, Paola; Salati, Simona; Rossi, Chiara; Zini, Roberta; Tagliafico, Enrico; Vannucchi, Alessandro Maria; Manfredini, Rossella
abstract

Primary Myelofibrosis (PMF) is a chronic Philadelphia-negative myeloproliferative neoplasm characterized by a skewed megakaryopoiesis and an overproduction of proinflammatory and profibrotic mediators that lead to the development of bone marrow (BM) fibrosis. Since we recently uncovered the upregulation of miR-34a-5p in PMF CD34+ hematopoietic progenitor cells (HPCs), in order to elucidate its role in PMF pathogenesis here we unravelled the effects of miR-34a-5p overexpression in HPCs. We showed that enforced expression of miR-34a-5p partially constrains proliferation and favours the megakaryocyte and monocyte/macrophage commitment of HPCs. Interestingly, we identified lymphoid enhancer-binding factor 1 (LEF1) and nuclear receptor subfamily 4, group A, member 2 (NR4A2) transcripts as miR-34a-5p-targets downregulated after miR-34a-5p overexpression in HPCs as well as in PMF CD34+ cells. Remarkably, the knockdown of NR4A2 in HPCs mimicked the antiproliferative effects of miR-34a-5p overexpression, while the silencing of LEF1 phenocopied the effects of miR-34a-5p overexpression on HPCs lineage choice, by favouring the megakaryocyte and monocyte/macrophage commitment. Collectively our data unravel the role of miR-34a-5p in HPCs fate decision and suggest that the increased expression of miR-34a-5p in PMF HPCs could be important for the skewing of megakaryopoiesis and the production of monocytes, that are key players in BM fibrosis in PMF patients.

2016 - Integrative analysis of copy number and gene expression data suggests novel pathogenetic mechanisms in primary myelofibrosis [Articolo su rivista]
Salati, Simona; Zini, Roberta; Nuzzo, Simona; Guglielmelli, Paola; Pennucci, Valentina; Prudente, Zelia; Ruberti, Samantha; Rontauroli, Sebastiano; Norfo, Ruggiero; Bianchi, Elisa; Bogani, Costanza; Rotunno, Giada; Fanelli, Tiziana; Mannarelli, Carmela; Rosti, Vittorio; Salmoiraghi, Silvia; Pietra, Daniela; Ferrari, Sergio; Barosi, Giovanni; Rambaldi, Alessandro; Cazzola, Mario; Bicciato, Silvio; Tagliafico, Enrico; Vannucchi, Alessandro M; Manfredini, Rossella
abstract

Primary myelofibrosis (PMF) is a Myeloproliferative Neoplasm (MPN) characterized by megakaryocyte hyperplasia, progressive bone marrow fibrosis, extramedullary hematopoiesis and transformation to Acute Myeloid Leukemia (AML). A number of phenotypic driver (JAK2, CALR, MPL) and additional subclonal mutations have been described in PMF, pointing to a complex genomic landscape. To discover novel genomic lesions that can contribute to disease phenotype and/or development, gene expression and copy number signals were integrated and several genomic abnormalities leading to a concordant alteration in gene expression levels were identified. In particular, copy number gain in the polyamine oxidase (PAOX) gene locus was accompanied by a coordinated transcriptional up-regulation in PMF patients. PAOX inhibition resulted in rapid cell death of PMF progenitor cells, while sparing normal cells, suggesting that PAOX inhibition could represent a therapeutic strategy to selectively target PMF cells without affecting normal hematopoietic cells' survival. Moreover, copy number loss in the chromatin modifier HMGXB4 gene correlates with a concomitant transcriptional down-regulation in PMF patients. Interestingly, silencing of HMGXB4 induces megakaryocyte differentiation, while inhibiting erythroid development, in human hematopoietic stem/progenitor cells. These results highlight a previously un-reported, yet potentially interesting role of HMGXB4 in the hematopoietic system and suggest that genomic and transcriptional imbalances of HMGXB4 could contribute to the aberrant expansion of the megakaryocytic lineage that characterizes PMF patients.

2016 - miR-382-5p Controls Hematopoietic Stem Cell Differentiation Through the Downregulation of MXD1 [Articolo su rivista]
Zini, Roberta; Rossi, Chiara; Norfo, Ruggiero; Pennucci, Valentina; Barbieri, Greta; Ruberti, Samantha; Rontauroli, Sebastiano; Salati, Simona; Bianchi, Elisa; Manfredini, Rossella
abstract

microRNAs are key regulators of gene expression that control stem cell fate by posttranscriptional downregulation of hundreds of target genes through seed pairing in their 3' untranslated region. In fact, miRNAs tightly regulate fundamental stem cell processes, like self-renewal, proliferation, and differentiation; therefore, miRNA deregulation may contribute to the development of solid tumors and hematological malignancies. miR-382-5p has been found to be upregulated in patients with myeloid neoplasms, but its role in normal hematopoiesis is still unknown. In this study, we demonstrated that miR-382-5p overexpression in CD34(+) hematopoietic stem/progenitor cells (HSPCs) leads to a significant decrease of megakaryocyte precursors coupled to increase of granulocyte ones. Furthermore, by means of a computational analysis using different prediction algorithms, we identified several putative mRNA targets of miR-382-5p that are downregulated upon miRNA overexpression (ie, FLI1, GATA2, MAF, MXD1, RUNX1, and SGK1). Among these, we validated MXD1 as real target of miR-382-5p by luciferase reporter assay. Finally, we showed that MXD1 knockdown mimics the effects of miR-382-5p overexpression on granulocyte and megakaryocyte differentiation of CD34(+) cells. Overall, our results demonstrated that miR-382-5p expression favors the expansion of granulocyte lineage and impairs megakaryocyte commitment through MXD1 downregulation. Therefore, our data showed for the first time that the miR-382-5p/MXD1 axis plays a critical role in myelopoiesis by affecting the lineage choice of CD34(+) HSPCs.

2016 - Tie2 expressing monocytes in the spleen of patients with primary myelofibrosis [Articolo su rivista]
Campanelli, R.; Fois, G.; Catarsi, P.; Poletto, V.; Villani, L.; Erba, B. G.; Maddaluno, L.; Jemos, B.; Salmoiraghi, S.; Guglielmelli, P.; Abbonante, V.; Di Buduo, C. A.; Balduini, A.; Iurlo, A.; Barosi, G.; Rosti, V.; Massa, M.; Vannucchi, A. M.; Balliu, M.; Bartalucci, N.; Bogani, C.; Bosi, A.; Calabresi, L.; Corbizzi Fattori, G.; Fanelli, T.; Fjerza, R.; Gesullo, F.; Mannarelli, C.; Merli, L.; Pacilli, A.; Pancrazzi, A.; Paoli, C.; Pieri, L.; Rotunno, G.; Sant'Antonio, E.; Bonetti, E.; Cazzola, M.; Ambaglio, I.; Bernasconi, P.; Casetti, C. I.; Catricala, S.; Elena, C.; Fugazza, E.; Galli, A.; Malcovati, L.; Milanesi, C.; Pascutto, C.; Pietra, D.; Ripamonti, F.; Rossi, M.; Rumi, E.; Dejana, E.; Breviario, F.; Corada, M.; Malinverno, M.; Rambaldi, A.; Chioda, G.; Ferrari, M. L.; Finazzi, G.; Finazzi, M. C.; Belotti, C.; Boroni, C.; Amaru, A.; Golay, J.; Bortoluzzi, S.; Bisognin, A.; Coppe, A.; Saccoman, C.; Manfredini, R.; Artuso, L.; Bernardis, I.; Bianchi, E.; Montanari, M.; Pennucci, V.; Prudente, Z.; Rontauroli, S.; Rossi, C.; Ruberti, S.; Salati, S.; Tagliafico, E.; Tenedini, E.; Zini, R.
abstract

Primary myelofibrosis (PMF) is a Philadelphia-negative (Ph-) myeloproliferative disorder, showing abnormal CD34 + progenitor cell trafficking, splenomegaly, marrow fibrosis leading to extensive extramedullary haematopoiesis, and abnormal neoangiogenesis in either the bone marrow or the spleen. Monocytes expressing the angiopoietin-2 receptor (Tie2) have been shown to support abnormal angiogenic processes in solid tumors through a paracrine action that takes place in proximity to the vessels. In this study we investigated the frequency of Tie2 expressing monocytes in the spleen tissue samples of patients with PMF, and healthy subjects (CTRLs), and evaluated their possible role in favouring spleen angiogenesis. We show by confocal microscopy that in the spleen tissue of patients with PMF, but not of CTRLs, the most of the CD14 + cells are Tie2 + and are close to vessels; by flow cytometry, we found that Tie2 expressing monocytes were Tie2 + CD14 low CD16 bright CDL62 - CCR2 - (TEMs) and their frequency was higher (p = 0.008) in spleen tissue-derived mononuclear cells (MNCs) of patients with PMF than in spleen tissue-derived MNCs from CTRLs undergoing splenectomy for abdominal trauma. By in vitro angiogenesis assay we evidenced that conditioned medium of immunomagnetically selected spleen tissue derived CD14 + cells of patients with PMF induced a denser tube like net than that of CTRLs; in addition, CD14 + Tie2 + cells sorted from spleen tissue derived single cell suspension of patients with PMF show a higher expression of genes involved in angiogenesis than that found in CTRLs. Our results document the enrichment of Tie2 + monocytes expressing angiogenic genes in the spleen of patients with PMF, suggesting a role for these cells in starting/maintaining the pathological angiogenesis in this organ.

2015 - MYB controls erythroid versus megakaryocyte lineage fate decision through the miR-486-3p-mediated downregulation of MAF [Articolo su rivista]
Bianchi, E.; Bulgarelli, J.; Ruberti, S.; Rontauroli, S.; Sacchi, G.; Norfo, R.; Pennucci, V.; Zini, R.; Salati, S.; Prudente, Z.; Ferrari, S.; Manfredini, R.
abstract

The transcription factor MYB has a key role in hematopoietic progenitor cells (HPCs) lineage choice, by enhancing erythropoiesis at the expense of megakaryopoiesis. We previously demonstrated that MYB controls erythroid versus megakaryocyte lineage decision by transactivating KLF1 and LMO2 expression. To further unravel the molecular mechanisms through which MYB affects lineage fate decision, we performed the integrative analysis of miRNA and mRNA changes in MYB-silenced human primary CD34+ HPCs. Among the miRNAs with the highest number of predicted targets, we focused our studies on hsa-miR-486-3p by demonstrating that MYB controls miR-486-3p expression through the transactivation of its host gene, ankyrin-1 (ANK1) and that miR-486-3p affects HPCs commitment. Indeed, overexpression and knockdown experiments demonstrated that miR-486-3p supports the erythropoiesis while restraining the megakaryopoiesis. Of note, miR-486-3p also favors granulocyte differentiation while repressing the macrophage differentiation. To shed some light on the molecular mechanisms through which miR-486-3p affects HPCs lineage commitment, we profiled the gene expression changes upon miR-486-3p overexpression in CD34+ cells. Among the genes downregulated in miR-486-3p-overexpressing HPCs and computationally predicted to be miR-486-3p targets, we identified MAF as a miR-486-3p target by 3′UTR luciferase reporter assay. Noteworthy, MAF overexpression was able to partially reverse the effects of miR-486-3p overexpression on erythroid versus megakaryocyte lineage choice. Moreover, the MYB/MAF co-silencing constrained the skewing of erythroid versus megakaryocyte lineage commitment in MYB-silenced CD34+ cells, by restraining the expansion of megakaryocyte lineage while partially rescuing the impairment of erythropoiesis. Therefore, our data collectively demonstrate that MYB favors erythropoiesis and restrains megakaryopoiesis through the transactivation of miR-486-3p expression and the subsequent downregulation of MAF. As a whole, our study uncovers the MYB/miR-486-3p/MAF axis as a new mechanism underlying the MYB-driven control of erythroid versus megakaryocyte lineage fate decision.

2014 - C-Myb Restrains Megakaryopoiesis through the Hsa-MiR-486-3p-Driven Down-Regulation of C-Maf [Abstract in Rivista]
Bianchi, Elisa; Bulgarelli, Jenny; Sacchi, Giorgia; Ruberti, Samantha; Norfo, Ruggiero; Rontauroli, Sebastiano; Pennucci, Valentina; Zini, Roberta; Salati, Simona; Prudente, Zelia; Ferrari, Sergio; Vannucchi, Alessandro M.; Manfredini, Rossella
abstract

INTRODUCTION The transcription factor c-Myb plays a key role in human primary CD34+ hematopoietic progenitor cells (HPCs) lineage choice, by enhancing erythropoiesis at the expense of megakaryopoiesis. We previously demonstrated that c-Myb affects erythroid versus megakaryocyte lineage decision in part by transactivating KLF1 and LMO2 expression. To further unravel the molecular mechanisms through which c-myb affects lineage fate decision, we profiled the miRNA and mRNA changes in myb-silenced CD34+ HPCs. METHODS RNA from CD34+ HPCs transfected with c-myb-targeting/non targeting control synthetic siRNAs was collected 24 hours post-Nucleofection for a set of 5 independent experiments. mRNA and miRNA expression for each sample were profiled by Affymetrix U219 GeneAtlas and Exiqon Human miRNome PCR Panel, respectively. miRNA/mRNA data were integrated by Ingenuity Pathway Analysis. The effects of hsa-miR-486-3p overexpression and c-Maf silencing on CD34+ cells differentiation ability were studied by morphological and immunophenotypic analyses after liquid culture and by collagen-based clonogenic assay. Furthermore, gene expression changes in CD34+ cells upon hsa-miR-486-3p overexpression were profiled by Affymetrix U219. RESULTS The integrative analysis of miRNA/mRNA expression changes upon c-myb silencing in human CD34+ HPCs highlighted a set of 19 miRNA with 150 anticorrelated putative target mRNAs. Among the miRNAs down-regulated in myb-silenced progenitors with the highest number of predicted target mRNAs, we selected hsa-miR-486-3p based on the in vitro effects of its overexpression on HPCs commitment. Indeed, morphological and flow cytometric analyses after liquid culture showed that hsa-miR-486-3p overexpression in HPCs enhanced erythroid and granulocyte differentiation while restraining megakaryocyte and macrophage differentiation. Moreover, collagen-based clonogenic assay demonstrated a strong impairement megakaryocyte commitment upon hsa-miR-486-3p-overexpression in CD34+ cells. Gene expression profiling of hsa-miR-486-3p overexpressing CD34+ cells enabled us to identify a set of 8 genes down-regulated and computationally predicted, putative hsa-miR-486-3p targets. Among them, we selected c-maf transcript as up-regulated upon myb silencing. Worth of note, c-maf silencing in CD34+ progenitor cells was able to reverse the affects of myb silencing on erythroid versus megakaryocyte lineage choice. CONCLUSIONS Integrative miRNA/mRNA analysis highlighted a set of miRNAs and anticorrelated putative target mRNAs modulated upon myb silencing, therefore potential players in myb-driven HPCs lineage choice. Among them, we demonstrated the hsa-miR-486-3p/c-maf pair as partially contributing to the effects of myb on HPCs commitment. Therefore, our data collectively identified myb-driven hsa-miR-486-3p up-regulation and subsequent c-maf down-regulation as a new molecular mechanism through which c-Myb favours erythropoiesis while restraining megakaryopoiesis.

2014 - miRNA-mRNA integrative analysis in primary myelofibrosis CD34+ cells: role of miR-155/JARID2 axis in abnormal megakaryopoiesis [Articolo su rivista]
Norfo, Ruggiero; Zini, Roberta; Pennucci, Valentina; Bianchi, Elisa; Salati, Simona; Guglielmelli, Paola; Bogani, Costanza; Fanelli, Tiziana; Mannarelli, Carmela; Rosti, Vittorio; Pietra, Daniela; Salmoiraghi, Silvia; Bisognin, Andrea; Ruberti, Samantha; Rontauroli, Sebastiano; Sacchi, Giorgia; Prudente, Zelia; Barosi, Giovanni; Cazzola, Mario; Rambaldi, Alessandro; Bortoluzzi, Stefania; Ferrari, Sergio; Tagliafico, Enrico; Vannucchi, Alessandro M; Manfredini, Rossella; Associazione Italiana per la Ricerca sul Cancro Gruppo Italiano Malattie Mieloproliferative, Investigators
abstract

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by megakaryocyte (MK) hyperplasia, bone marrow fibrosis, and abnormal stem cell trafficking. PMF may be associated with somatic mutations in JAK2, MPL, or CALR. Previous studies have shown that abnormal MKs play a central role in the pathophysiology of PMF. In this work, we studied both gene and microRNA (miRNA) expression profiles in CD34(+) cells from PMF patients. We identified several biomarkers and putative molecular targets such as FGR, LCN2, and OLFM4. By means of miRNA-gene expression integrative analysis, we found different regulatory networks involved in the dysregulation of transcriptional control and chromatin remodeling. In particular, we identified a network gathering several miRNAs with oncogenic potential (eg, miR-155-5p) and targeted genes whose abnormal function has been previously associated with myeloid neoplasms, including JARID2, NR4A3, CDC42, and HMGB3. Because the validation of miRNA-target interactions unveiled JARID2/miR-155-5p as the strongest relationship in the network, we studied the function of this axis in normal and PMF CD34(+) cells. We showed that JARID2 downregulation mediated by miR-155-5p overexpression leads to increased in vitro formation of CD41(+) MK precursors. These findings suggest that overexpression of miR-155-5p and the resulting downregulation of JARID2 may contribute to MK hyperplasia in PMF.