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Hans D. Ochs - One of the best experts on this subject based on the ideXlab platform.
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r loops cause genomic instability in t helper lymphocytes from patients with wiskott Aldrich Syndrome
The Journal of Allergy and Clinical Immunology, 2018Co-Authors: Koustav Sarkar, Loic Dupre, Hans D. Ochs, Seongsu Han, Kuokuang Wen, Michael M Seidman, Yatin M VyasAbstract:Background Wiskott-Aldrich Syndrome (WAS), X-linked thrombocytopenia (XLT), and X-linked neutropenia, which are caused by WAS mutations affecting Wiskott-Aldrich Syndrome protein (WASp) expression or activity, manifest in immunodeficiency, autoimmunity, genomic instability, and lymphoid and other cancers. WASp supports filamentous actin formation in the cytoplasm and gene transcription in the nucleus. Although the genetic basis for XLT/WAS has been clarified, the relationships between mutant forms of WASp and the diverse features of these disorders remain ill-defined. Objective We sought to define how dysfunctional gene transcription is causally linked to the degree of T H cell deficiency and genomic instability in the XLT/WAS clinical spectrum. Methods In human T H 1- or T H 2-skewing cell culture systems, cotranscriptional R-loops (RNA/DNA duplex and displaced single-stranded DNA) and DNA double-strand breaks (DSBs) were monitored in multiple samples from patients with XLT and WAS and in normal T cells depleted of WASp. Results WASp deficiency provokes increased R-loops and R-loop–mediated DSBs in T H 1 cells relative to T H 2 cells. Mechanistically, chromatin occupancy of serine 2-unphosphorylated RNA polymerase II is increased, and that of topoisomerase 1, an R-loop preventing factor, is decreased at R-loop–enriched regions of IFNG and TBX21 (T H 1 genes) in T H 1 cells. These aberrations accompany increased unspliced (intron-retained) and decreased spliced mRNA of IFNG and TBX21 but not IL13 (T H 2 gene). Significantly, increased cellular load of R-loops and DSBs, which are normalized on RNaseH1-mediated suppression of ectopic R-loops, inversely correlates with disease severity scores. Conclusion Transcriptional R-loop imbalance is a novel molecular defect causative in T H 1 immunodeficiency and genomic instability in patients with WAS. The study proposes that cellular R-loop load could be used as a potential biomarker for monitoring symptom severity and prognostic outcome in the XLT-WAS clinical spectrum and could be targeted therapeutically.
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clinical spectrum pathophysiology and treatment of the wiskott Aldrich Syndrome
Current Opinion in Hematology, 2011Co-Authors: Michael H Albert, Luigi D. Notarangelo, Hans D. OchsAbstract:Purpose of review The Wiskott-Aldrich Syndrome (WAS), caused by mutations in the WAS gene, is a complex and diverse disorder with X-linked inheritance. This review focuses on recent developments in the understanding of its basic pathophysiology, diverse clinical phenotypes and optimal patient management including novel therapies. Recent findings The protein encoded by the WAS gene is a multifunctional signaling element expressed in immune and hematopoietic cells that plays a critical role in cytoskeletal reorganization, immune synapse formation and intracellular signaling. The type of specific mutation, its location within the gene and its effect on protein expression play a major role in determining an individual patient's clinical phenotype. Recent clinical observations and molecular studies have created a sophisticated picture of the disease spectrum. The improved outcome of stem cell transplantation from related and unrelated matched donors and promising early results from the first clinical gene therapy trial have added new therapeutic options for these patients. Summary Classic WAS, X-linked thrombocytopenia and X-linked neutropenia are caused by WAS gene mutations, each having a distinct pattern of clinical symptoms and disease severity. New developments in the understanding of these Syndromes and novel therapeutic options will have a major impact on the treatment of individuals with WAS mutations.
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mutations of the wiskott Aldrich Syndrome protein affect protein expression and dictate the clinical phenotypes
Immunologic Research, 2009Co-Authors: Hans D. OchsAbstract:Mutations of the Wiskott–Aldrich Syndrome Protein (WASP) are responsible for classic Wiskott–Aldrich Syndrome (WAS), X-linked thrombocytopenia (XLT), and in rare instances congenital X-linked neutropenia (XLN). WASP is a regulator of actin polymerization in hematopoietic cells with well-defined functional domains that are involved in cell signaling and cell locomotion, immune synapse formation, and apoptosis. Mutations of WASP are located throughout the gene and either inhibit or disregulate normal WASP function. Analysis of a large patient population demonstrates a strong phenotype–genotype correlation. Classic WAS occurs when WASP is absent, XLT when mutated WASP is expressed and XLN when missense mutations occur in the Cdc42-binding site. However, because there are exceptions to this rule it is difficult to predict the long-term prognosis of a given affected boy solely based on the analysis of WASP expression.
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wiskott Aldrich Syndrome
Current Opinion in Hematology, 2008Co-Authors: Luigi D. Notarangelo, Carol H Miao, Hans D. OchsAbstract:Purpose of reviewWiskott-Aldrich Syndrome is caused by mutations of the Wiskott-Aldrich Syndrome protein gene, which codes for a cytoplasmic protein with multiple functions. This review will focus on recent progress in understanding the molecular basis of Wiskott-Aldrich Syndrome and its ramificatio
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the wiskott Aldrich Syndrome protein regulates nuclear translocation of nfat2 and nf κb rela independently of its role in filamentous actin polymerization and actin cytoskeletal rearrangement
Journal of Immunology, 2005Co-Authors: Winifred Huang, Hans D. Ochs, Bo Dupont, Yatin M VyasAbstract:Effector functions mediated by NK cells involve cytotoxicity and transcription-dependent production and release of cytokines and chemokines. Although the JAK/STAT pathway mediates lymphokine-induced transcriptional regulation in NK cells, very little is known about transcriptional regulation induced during cell-cell contact. We demonstrate that the Wiskott-Aldrich Syndrome protein (WASp) is an important component for integration of signals leading to nuclear translocation of NFAT2 and NF-κB (RelA) during cell-cell contact and NKp46-dependent signaling. This WASp function is independent of its known role in F-actin polymerization and cytoskeletal rearrangement. Absence of WASp results in decreased accumulation of calcineurin, WASp-interacting protein, and molecules upstream of calcium mobilization, i.e., activated ZAP70 and phospholipase C-γ1, in the disorganized NK cell immune synapse. Production of GM-CSF, but not IFN-γ, is decreased, while natural cytotoxicity of Wiskott-Aldrich Syndrome-NK cells is maintained. Our results indicate that WASp independently regulates its dual functions, i.e., actin cytoskeletal remodeling and transcription in NK cells.
Scott B. Snapper - One of the best experts on this subject based on the ideXlab platform.
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neuronal wiskott Aldrich Syndrome protein regulates tgf β1 mediated lung vascular permeability
The FASEB Journal, 2016Co-Authors: Brant M Wagener, Scott B. Snapper, Anni Zheng, Xueke Zhao, Pulin Che, Angela Brandon, Naseem Anjum, Judy Creighton, Junlin Guan, Qimei HanAbstract:TGF-β1 induces an increase in paracellular permeability and actin stress fiber formation in lung microvascular endothelial and alveolar epithelial cells via small Rho GTPase. The molecular mechanism involved is not fully understood. Neuronal Wiskott-Aldrich Syndrome protein (N-WASP) has an essential role in actin structure dynamics. We hypothesized that N-WASP plays a critical role in these TGF-β1-induced responses. In these cell monolayers, we demonstrated that N-WASP down-regulation by short hairpin RNA prevented TGF-β1-mediated disruption of the cortical actin structure, actin stress filament formation, and increased permeability. Furthermore, N-WASP down-regulation blocked TGF-β1 activation mediated by IL-1β in alveolar epithelial cells, which requires actin stress fiber formation. Control short hairpin RNA had no effect on these TGF-β1-induced responses. TGF-β1-induced phosphorylation of Y256 of N-WASP via activation of small Rho GTPase and focal adhesion kinase mediates TGF-β1-induced paracellular permeability and actin cytoskeleton dynamics. In vivo, compared with controls, N-WASP down-regulation increases survival and prevents lung edema in mice induced by bleomycin exposure-a lung injury model in which TGF-β1 plays a critical role. Our data indicate that N-WASP plays a crucial role in the development of TGF-β1-mediated acute lung injury by promoting pulmonary edema via regulation of actin cytoskeleton dynamics.-Wagener, B. M., Hu, M., Zheng, A., Zhao, X., Che, P., Brandon, A., Anjum, N., Snapper, S., Creighton, J., Guan, J.-L., Han, Q., Cai, G.-Q., Han, X., Pittet, J.-F., Ding, Q. Neuronal Wiskott-Aldrich Syndrome protein regulates TGF-β1-mediated lung vascular permeability.
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neural wiskott Aldrich Syndrome protein modulates wnt signaling and is required for hair follicle cycling in mice
Journal of Clinical Investigation, 2010Co-Authors: Anna Lyubimova, John J Garber, Geeta Upadhyay, Andrey A Sharov, Florentina Anastasoaie, Vijay Yajnik, George Cotsarelis, Gian Paolo Dotto, Vladimir A Botchkarev, Scott B. SnapperAbstract:The Rho family GTPases Cdc42 and Rac1 are critical regulators of the actin cytoskeleton and are essential for skin and hair function. Wiskott-Aldrich Syndrome family proteins act downstream of these GTPases, controlling actin assembly and cytoskeletal reorganization, but their role in epithelial cells has not been characterized in vivo. Here, we used a conditional knockout approach to assess the role of neural Wiskott-Aldrich Syndrome protein (N-WASP), the ubiquitously expressed Wiskott-Aldrich Syndrome-like (WASL) protein, in mouse skin. We found that N-WASP deficiency in mouse skin led to severe alopecia, epidermal hyperproliferation, and ulceration, without obvious effects on epidermal differentiation and wound healing. Further analysis revealed that the observed alopecia was likely the result of a progressive and ultimately nearly complete block in hair follicle (HF) cycling by 5 months of age. N-WASP deficiency also led to abnormal proliferation of skin progenitor cells, resulting in their depletion over time. Furthermore, N-WASP deficiency in vitro and in vivo correlated with decreased GSK-3beta phosphorylation, decreased nuclear localization of beta-catenin in follicular keratinocytes, and decreased Wnt-dependent transcription. Our results indicate a critical role for N-WASP in skin function and HF cycling and identify a link between N-WASP and Wnt signaling. We therefore propose that N-WASP acts as a positive regulator of beta-catenin-dependent transcription, modulating differentiation of HF progenitor cells.
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lymphocyte dependent and th2 cytokine associated colitis in mice deficient in wiskott Aldrich Syndrome protein
Gastroenterology, 2007Co-Authors: Deanna D Nguyen, Michel H. Maillard, Cathryn R Nagler, Atul K Bhan, Vinicius Cotta De Almeida, Emiko Mizoguchi, Christoph Klein, Ivan J Fuss, Atsushi Mizoguchi, Scott B. SnapperAbstract:Background & Aims: Controversy exists as to whether patients with inflammatory bowel disease have an underlying immunodeficiency. We have focused on a murine model of the Wiskott-Aldrich Syndrome, an immunodeficiency in which autoimmunity can manifest in the form of an inflammatory bowel disease-like illness. Wiskott-Aldrich Syndrome protein (WASP) deficiency in mice results in similar clinical features. Herein, we characterized the colitis in WASP-deficient mice. Methods: WASP-deficient mice were followed clinically and histologically. Immunologic studies were performed to determine the pathogenic cell population(s), the predominant cytokine expression pattern, and the role of cytokine(s) in colitis pathogenesis. Results: All WASP-deficient mice develop colitis by 6 months of age. Lymphocytes are required for disease induction, and CD4+ T cells from WASP-deficient mice are sufficient to induce disease in lymphocyte-deficient hosts. Lamina propria preparations from WASP-deficient mice demonstrated elevations in interferon-γ, interleukin (IL)-4, and IL-13 levels but decreased IL-6 and no difference in IL-17 expression in comparison with wild-type controls. Treatment with neutralizing antibody to IL-4, but not to interferon-γ, abrogated colitis development. However, mice deficient in both WASP and IL-4 showed no difference in histologic colitis scores at 24 weeks of age compared with WASP-deficient mice. Conclusions: These results demonstrate a critical role for lymphocytes and a relative T helper 2 cytokine predominance in the colitis associated with WASP-deficient mice. This is the only model of colitis with elevated T helper 2 cytokines and aberrant natural regulatory T cell function and is unique in having a human disease counterpart with similar defects.
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wiskott Aldrich Syndrome protein wasp and n wasp are critical for t cell development
Proceedings of the National Academy of Sciences of the United States of America, 2007Co-Authors: Vinicius Cottadealmeida, Michel H. Maillard, Dilek Onaldi, Heather Wachtel, Parool Meelu, Ung-il Chung, Ramnik J. Xavier, Frederick W. Alt, Scott B. SnapperAbstract:Although T cell dysfunction and lymphopenia are key features of immunodeficient patients with the Wiskott-Aldrich Syndrome and Wiskott-Aldrich Syndrome protein (WASP)-deficient mice, T cell development appears relatively normal. We hypothesized that N-WASP, a ubiquitously expressed homologue of WASP, may serve a redundant function with WASP. To examine the unique and redundant activities of WASP and N-WASP, we generated ES cells devoid of WASP and N-WASP [double knockout (DKO)] and used the RAG-2-deficient blastocyst complementation system to generate DKO lymphocytes. Moreover, we mated WASP KO mice with mice containing a conditionally targeted N-WASP allele and used the Cre-loxP system to generate mice lacking WASP and N-WASP in T cells [conditional DKO (cDKO)]. In both systems, N-WASP-deficient cells were indistinguishable from WT cells. In contrast, T cell development in DKO and cDKO mice was markedly altered, as shown by thymic hypocellularity and reduced numbers of peripheral T cells. We found that the combined activity of WASP and N-WASP was important for CD4(-)CD8(-) double-negative (DN)-to-CD4(+)CD8(+) double-positive (DP) cell transition, and this may be partly explained by reduced cycling DN3 cells. In addition, decreased migratory responses of CD4(+)CD8(-) and CD4(-)CD8(+) single-positive (SP) cells and increased percentage of CD69(low)CD24(low) and CD62L(low) SP cells in cDKO cells imply retention of SP cells in the thymus. In summary, this study suggests that, although WASP serves a unique role for peripheral T cell function, T cell development depends on the combined activity of WASP and N-WASP.
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the wiskott Aldrich Syndrome protein is required for the function of cd4 cd25 foxp3 regulatory t cells
Journal of Experimental Medicine, 2007Co-Authors: Michel H. Maillard, Vinicius Cottadealmeida, Fuminao Takeshima, Deanna D Nguyen, Pierre Michetti, Cathryn R Nagler, Atul K Bhan, Scott B. SnapperAbstract:The Wiskott-Aldrich Syndrome, a primary human immunodeficiency, results from defective expression of the hematopoietic-specific cytoskeletal regulator Wiskott-Aldrich Syndrome protein (WASP). Because CD4+CD25+Foxp3+ naturally occurring regulatory T (nTreg) cells control autoimmunity, we asked whether colitis in WASP knockout (WKO) mice is associated with aberrant development/function of nTreg cells. We show that WKO mice have decreased numbers of CD4+CD25+Foxp3+ nTreg cells in both the thymus and peripheral lymphoid organs. Moreover, we demonstrate that WKO nTreg cells are markedly defective in both their ability to ameliorate the colitis induced by the transfer of CD45RBhi T cells and in functional suppression assays in vitro. Compared with wild-type (WT) nTreg cells, WKO nTreg cells show significantly impaired homing to both mucosal (mesenteric) and peripheral sites upon adoptive transfer into WT recipient mice. Suppression defects may be independent of antigen receptor–mediated actin rearrangement because both WT and WKO nTreg cells remodeled their actin cytoskeleton inefficiently upon T cell receptor stimulation. Preincubation of WKO nTreg cells with exogenous interleukin (IL)-2, combined with antigen receptor–mediated activation, substantially rescues the suppression defects. WKO nTreg cells are also defective in the secretion of the immunomodulatory cytokine IL-10. Overall, our data reveal a critical role for WASP in nTreg cell function and implicate nTreg cell dysfunction in the autoimmunity associated with WASP deficiency.
Maria Carmina Castiello - One of the best experts on this subject based on the ideXlab platform.
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neutrophils drive type i interferon production and autoantibodies in patients with wiskott Aldrich Syndrome
The Journal of Allergy and Clinical Immunology, 2018Co-Authors: Karla E Cervantesluevano, Maria Carmina Castiello, Marita Bosticardo, Nicoletta Caronni, Elena Fontana, Giulia Maria Piperno, Asma Naseem, Paolo Uva, Genni Enza MarcovecchioAbstract:Background Wiskott-Aldrich Syndrome (WAS) is a rare primary immunodeficiency caused by mutations in Wiskott-Aldrich Syndrome protein (WASp), a key regulator of cytoskeletal dynamics in hematopoietic cells. A high proportion of patients experience autoimmunity caused by a breakdown in T- and B-cell tolerance. Moreover, excessive production of type I interferon (IFN-I) by plasmacytoid dendritic cells (pDCs) contributes to autoimmune signs; however, the factors that trigger excessive innate activation have not been defined. Objective Neutrophil extracellular traps (NETs) emerged as major initiating factors in patients with diseases such as systemic lupus erythematosus and rheumatoid arthritis. In this study we explored the possible involvement of aberrant neutrophil functions in patients with WAS. Methods We evaluated the expression of a set of granulocyte genes associated with NETs in a cohort of patients with WAS and the presence of NET inducers in sera. Using a mouse model of WAS, we analyzed NET release by WASp-null neutrophils and evaluated the composition and homeostasis of neutrophils in vivo . By using depletion experiments, we assessed the effect of neutrophils in promoting inflammation and reactivity against autoantigens. Results Transcripts of genes encoding neutrophil enzymes and antimicrobial peptides were increased in granulocytes of patients with WAS, and serum-soluble factors triggered NET release. WASp-null neutrophils showed increased spontaneous NETosis, induced IFN-I production by pDCs, and activated B cells through B-cell activating factor. Consistently, their depletion abolished constitutive pDC activation, normalized circulating IFN-I levels, and, importantly, abolished production of autoantibodies directed against double-stranded DNA, nucleosomes, and myeloperoxidase. Conclusions These findings reveal that neutrophils are involved in the pathogenic loop that causes excessive activation of innate cells and autoreactive B cells, thus identifying novel mechanisms that contribute to the autoimmunity of WAS.
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autonomous role of wiskott Aldrich Syndrome platelet deficiency in inducing autoimmunity and inflammation
The Journal of Allergy and Clinical Immunology, 2018Co-Authors: Lucia Piceni Sereni, Adrian J. Thrasher, Maria Carmina Castiello, Francesco Marangoni, Achille Anselmo, Dario Di Silvestre, Sara Motta, Elena Draghici, Stefano Mantero, Silvia GilianiAbstract:Background Wiskott-Aldrich Syndrome (WAS) is an X-linked immunodeficiency characterized by eczema, infections, and susceptibility to autoimmunity and malignancies. Thrombocytopenia is a constant finding, but its pathogenesis remains elusive. Objective To dissect the basis of the WAS platelet defect, we used a novel conditional mouse model (CoWas) lacking Wiskott-Aldrich Syndrome protein (WASp) only in the megakaryocytic lineage in the presence of a normal immunologic environment, and in parallel we analyzed samples obtained from patients with WAS. Methods Phenotypic and functional characterization of megakaryocytes and platelets in mutant CoWas mice and patients with WAS with and without autoantibodies was performed. Platelet antigen expression was examined through a protein expression profile and cluster proteomic interaction network. Platelet immunogenicity was tested by using ELISAs and B-cell and platelet cocultures. Results CoWas mice showed increased megakaryocyte numbers and normal thrombopoiesis in vitro , but WASp-deficient platelets had short lifespan and high expression of activation markers. Proteomic analysis identified signatures compatible with defects in cytoskeletal reorganization and metabolism yet surprisingly increased antigen-processing capabilities. In addition, WASp-deficient platelets expressed high levels of surface and soluble CD40 ligand and were capable of inducing B-cell activation in vitro . WASp-deficient platelets were highly immunostimulatory in mice and triggered the generation of antibodies specific for WASp-deficient platelets, even in the context of a normal immune system. Patients with WAS also showed platelet hyperactivation and increased plasma soluble CD40 ligand levels correlating with the presence of autoantibodies. Conclusion Overall, these findings suggest that intrinsic defects in WASp-deficient platelets decrease their lifespan and dysregulate immune responses, corroborating the role of platelets as modulators of inflammation and immunity.
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b cell reconstitution after lentiviral vector mediated gene therapy in patients with wiskott Aldrich Syndrome
The Journal of Allergy and Clinical Immunology, 2015Co-Authors: Maria Carmina Castiello, Lucia Piceni Sereni, Francesca Pala, Samantha Scaramuzza, Paolo Uva, Francesca Ferrua, Immacolata Brigida, Mirjam Van Der Burg, Giorgio Ottaviano, Michael H AlbertAbstract:Background Wiskott-Aldrich Syndrome (WAS) is a severe X-linked immunodeficiency characterized by microthrombocytopenia, eczema, recurrent infections, and susceptibility to autoimmunity and lymphomas. Hematopoietic stem cell transplantation is the treatment of choice; however, administration of WAS gene–corrected autologous hematopoietic stem cells has been demonstrated as a feasible alternative therapeutic approach. Objective Because B-cell homeostasis is perturbed in patients with WAS and restoration of immune competence is one of the main therapeutic goals, we have evaluated reconstitution of the B-cell compartment in 4 patients who received autologous hematopoietic stem cells transduced with lentiviral vector after a reduced-intensity conditioning regimen combined with anti-CD20 administration. Methods We evaluated B-cell counts, B-cell subset distribution, B cell–activating factor and immunoglobulin levels, and autoantibody production before and after gene therapy (GT). WAS gene transfer in B cells was assessed by measuring vector copy numbers and expression of Wiskott-Aldrich Syndrome protein. Results After lentiviral vector-mediated GT, the number of transduced B cells progressively increased in the peripheral blood of all patients. Lentiviral vector-transduced progenitor cells were able to repopulate the B-cell compartment with a normal distribution of B-cell subsets both in bone marrow and the periphery, showing a WAS protein expression profile similar to that of healthy donors. In addition, after GT, we observed a normalized frequency of autoimmune-associated CD19 + CD21 − CD35 − and CD21 low B cells and a reduction in B cell–activating factor levels. Immunoglobulin serum levels and autoantibody production improved in all treated patients. Conclusions We provide evidence that lentiviral vector-mediated GT induces transgene expression in the B-cell compartment, resulting in ameliorated B-cell development and functionality and contributing to immunologic improvement in patients with WAS.
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wiskott Aldrich Syndrome protein deficiency perturbs the homeostasis of b cell compartment in humans
Journal of Autoimmunity, 2014Co-Authors: Maria Carmina Castiello, Marita Bosticardo, Francesca Pala, Marco Catucci, Nicolas Chamberlain, Menno C Van Zelm, Gertjan J Driessen, Malgorzata Pac, Ewa Bernatowska, Samantha ScaramuzzaAbstract:Wiskott–Aldrich Syndrome protein (WASp) regulates the cytoskeleton in hematopoietic cells and mutations in its gene cause the Wiskott–Aldrich Syndrome (WAS), a primary immunodeficiency with microthrombocytopenia, eczema and a higher susceptibility to develop tumors. Autoimmune manifestations, frequently observed in WAS patients, are associated with an increased risk of mortality and still represent an unsolved aspect of the disease. B cells play a crucial role both in immune competence and self-tolerance and defects in their development and function result in immunodeficiency and/or autoimmunity. We performed a phenotypical and molecular analysis of central and peripheral B-cell compartments in WAS pediatric patients. We found a decreased proportion of immature B cells in the bone marrow correlating with an increased presence of transitional B cells in the periphery. These results could be explained by the defective migratory response of WAS B cells to SDF-1α, essential for the retention of immature B cells in the BM. In the periphery, we observed an unusual expansion of CD21low B-cell population and increased plasma BAFF levels that may contribute to the high susceptibility to develop autoimmune manifestations in WAS patients. WAS memory B cells were characterized by a reduced in vivo proliferation, decreased somatic hypermutation and preferential usage of IGHV4-34, an immunoglobulin gene commonly found in autoreactive B cells. In conclusion, our findings demonstrate that WASp-deficiency perturbs B-cell homeostasis thus adding a new layer of immune dysregulation concurring to the increased susceptibility to develop autoimmunity in WAS patients.
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Lentiviral hematopoietic stem cell gene therapy in patients with Wiskott-Aldrich Syndrome
Science, 2013Co-Authors: A. Aiuti, Samantha Scaramuzza, Francesca Ferrua, L. Biasco, M. P. Cicalese, C. Baricordi, F. Dionisio, A. Calabria, S. Giannelli, Maria Carmina CastielloAbstract:Wiskott-Aldrich Syndrome (WAS) is an inherited immunodeficiency caused by mutations in the gene encoding WASP, a protein regulating the cytoskeleton. Hematopoietic stem/progenitor cell (HSPC) transplants can be curative, but, when matched donors are unavailable, infusion of autologous HSPCs modified ex vivo by gene therapy is an alternative approach. We used a lentiviral vector encoding functional WASP to genetically correct HSPCs from three WAS patients and reinfused the cells after a reduced-intensity conditioning regimen. All three patients showed stable engraftment of WASP-expressing cells and improvements in platelet counts, immune functions, and clinical scores. Vector integration analyses revealed highly polyclonal and multilineage haematopoiesis resulting from the gene-corrected HSPCs. Lentiviral gene therapy did not induce selection of integrations near oncogenes, and no aberrant clonal expansion was observed after 20 to 32 months. Although extended clinical observation is required to establish long-term safety, lentiviral gene therapy represents a promising treatment for WAS.
Adrian J. Thrasher - One of the best experts on this subject based on the ideXlab platform.
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how i manage patients with wiskott Aldrich Syndrome
British Journal of Haematology, 2019Co-Authors: Elizabeth Rivers, Adrian J. Thrasher, Austen Worth, Siobhan O BurnsAbstract:Wiskott Aldrich Syndrome (WAS) is a primary immunodeficiency disease resulting in recurrent infections, eczema and microthrombocytopaenia. In its classical form, significant combined immune deficiency, autoimmune complications and risk of haematological malignancy necessitate early correction with stem cell transplantation or gene therapy. A milder form, X-linked thrombocytopaenia (XLT), shares similar bleeding risk from thrombocytopaenia but is not associated with other significant clinical features and is generally managed conservatively. Here, we detail our approach to the diagnosis and treatment of classical WAS and XLT.
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autonomous role of wiskott Aldrich Syndrome platelet deficiency in inducing autoimmunity and inflammation
The Journal of Allergy and Clinical Immunology, 2018Co-Authors: Lucia Piceni Sereni, Adrian J. Thrasher, Maria Carmina Castiello, Francesco Marangoni, Achille Anselmo, Dario Di Silvestre, Sara Motta, Elena Draghici, Stefano Mantero, Silvia GilianiAbstract:Background Wiskott-Aldrich Syndrome (WAS) is an X-linked immunodeficiency characterized by eczema, infections, and susceptibility to autoimmunity and malignancies. Thrombocytopenia is a constant finding, but its pathogenesis remains elusive. Objective To dissect the basis of the WAS platelet defect, we used a novel conditional mouse model (CoWas) lacking Wiskott-Aldrich Syndrome protein (WASp) only in the megakaryocytic lineage in the presence of a normal immunologic environment, and in parallel we analyzed samples obtained from patients with WAS. Methods Phenotypic and functional characterization of megakaryocytes and platelets in mutant CoWas mice and patients with WAS with and without autoantibodies was performed. Platelet antigen expression was examined through a protein expression profile and cluster proteomic interaction network. Platelet immunogenicity was tested by using ELISAs and B-cell and platelet cocultures. Results CoWas mice showed increased megakaryocyte numbers and normal thrombopoiesis in vitro , but WASp-deficient platelets had short lifespan and high expression of activation markers. Proteomic analysis identified signatures compatible with defects in cytoskeletal reorganization and metabolism yet surprisingly increased antigen-processing capabilities. In addition, WASp-deficient platelets expressed high levels of surface and soluble CD40 ligand and were capable of inducing B-cell activation in vitro . WASp-deficient platelets were highly immunostimulatory in mice and triggered the generation of antibodies specific for WASp-deficient platelets, even in the context of a normal immune system. Patients with WAS also showed platelet hyperactivation and increased plasma soluble CD40 ligand levels correlating with the presence of autoantibodies. Conclusion Overall, these findings suggest that intrinsic defects in WASp-deficient platelets decrease their lifespan and dysregulate immune responses, corroborating the role of platelets as modulators of inflammation and immunity.
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current and emerging treatment options for wiskott Aldrich Syndrome
Expert Review of Clinical Immunology, 2015Co-Authors: Austen Worth, Adrian J. ThrasherAbstract:Wiskott-Aldrich Syndrome is a life-threatening primary immunodeficiency associated with a bleeding tendency, eczema and a high incidence of autoimmunity and malignancy. Stem cell transplantation offers the opportunity of cure for all these complications, and over the past 35 years there has been a remarkable improvement in survival following this treatment. Here, we review advances in management of clinical complications pre- and post-transplant, as well as discuss the morbidity Wiskott-Aldrich Syndrome patients experience following treatment. For patients with a poorly matched stem cell donor, recent gene therapy trials demonstrate encouraging results and the potential of low-toxicity therapy for all patients.
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the wiskott Aldrich Syndrome the actin cytoskeleton and immune cell function
Disease Markers, 2010Co-Authors: Michael P Blundell, Austen Worth, Gerben Bouma, Adrian J. ThrasherAbstract:Wiskott-Aldrich Syndrome (WAS) is a rare X-linked recessive primary immunodeficiency characterised by immune dysregulation, microthrombocytopaenia, eczema and lymphoid malignancies. Mutations in the WAS gene can lead to distinct Syndrome variations which largely, although not exclusively, depend upon the mutation. Premature termination and deletions abrogate Wiskott-Aldrich Syndrome protein (WASp) expression and lead to severe disease (WAS). Missense mutations usually result in reduced protein expression and the phenotypically milder X-linked thrombocytopenia (XLT) or attenuated WAS [1-3]. More recently however novel activating mutations have been described that give rise to X-linked neutropenia (XLN), a third Syndrome defined by neutropenia with variable myelodysplasia [4-6]. WASP is key in transducing signals from the cell surface to the actin cytoskeleton, and a lack of WASp results in cytoskeletal defects that compromise multiple aspects of normal cellular activity including proliferation, phagocytosis, immune synapse formation, adhesion and directed migration.
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wiskott Aldrich Syndrome immunodeficiency resulting from defective cell migration and impaired immunostimulatory activation
Immunobiology, 2009Co-Authors: Gerben Bouma, Adrian J. Thrasher, Siobhan O BurnsAbstract:Regulation of the actin cytoskeleton is crucial for many aspects of correct and cooperative functioning of immune cells, such as migration, antigen uptake and cell activation. The Wiskott–Aldrich Syndrome protein (WASp) is an important regulator of actin cytoskeletal rearrangements and lack of this protein results in impaired immune function. This review discusses recent new insights of the role of WASp at molecular and cellular level and evaluates how WASp deficiency affects important immunological features and how defective immune cell function contributes to compromised host defence.
Samantha Scaramuzza - One of the best experts on this subject based on the ideXlab platform.
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b cell reconstitution after lentiviral vector mediated gene therapy in patients with wiskott Aldrich Syndrome
The Journal of Allergy and Clinical Immunology, 2015Co-Authors: Maria Carmina Castiello, Lucia Piceni Sereni, Francesca Pala, Samantha Scaramuzza, Paolo Uva, Francesca Ferrua, Immacolata Brigida, Mirjam Van Der Burg, Giorgio Ottaviano, Michael H AlbertAbstract:Background Wiskott-Aldrich Syndrome (WAS) is a severe X-linked immunodeficiency characterized by microthrombocytopenia, eczema, recurrent infections, and susceptibility to autoimmunity and lymphomas. Hematopoietic stem cell transplantation is the treatment of choice; however, administration of WAS gene–corrected autologous hematopoietic stem cells has been demonstrated as a feasible alternative therapeutic approach. Objective Because B-cell homeostasis is perturbed in patients with WAS and restoration of immune competence is one of the main therapeutic goals, we have evaluated reconstitution of the B-cell compartment in 4 patients who received autologous hematopoietic stem cells transduced with lentiviral vector after a reduced-intensity conditioning regimen combined with anti-CD20 administration. Methods We evaluated B-cell counts, B-cell subset distribution, B cell–activating factor and immunoglobulin levels, and autoantibody production before and after gene therapy (GT). WAS gene transfer in B cells was assessed by measuring vector copy numbers and expression of Wiskott-Aldrich Syndrome protein. Results After lentiviral vector-mediated GT, the number of transduced B cells progressively increased in the peripheral blood of all patients. Lentiviral vector-transduced progenitor cells were able to repopulate the B-cell compartment with a normal distribution of B-cell subsets both in bone marrow and the periphery, showing a WAS protein expression profile similar to that of healthy donors. In addition, after GT, we observed a normalized frequency of autoimmune-associated CD19 + CD21 − CD35 − and CD21 low B cells and a reduction in B cell–activating factor levels. Immunoglobulin serum levels and autoantibody production improved in all treated patients. Conclusions We provide evidence that lentiviral vector-mediated GT induces transgene expression in the B-cell compartment, resulting in ameliorated B-cell development and functionality and contributing to immunologic improvement in patients with WAS.
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wiskott Aldrich Syndrome protein deficiency perturbs the homeostasis of b cell compartment in humans
Journal of Autoimmunity, 2014Co-Authors: Maria Carmina Castiello, Marita Bosticardo, Francesca Pala, Marco Catucci, Nicolas Chamberlain, Menno C Van Zelm, Gertjan J Driessen, Malgorzata Pac, Ewa Bernatowska, Samantha ScaramuzzaAbstract:Wiskott–Aldrich Syndrome protein (WASp) regulates the cytoskeleton in hematopoietic cells and mutations in its gene cause the Wiskott–Aldrich Syndrome (WAS), a primary immunodeficiency with microthrombocytopenia, eczema and a higher susceptibility to develop tumors. Autoimmune manifestations, frequently observed in WAS patients, are associated with an increased risk of mortality and still represent an unsolved aspect of the disease. B cells play a crucial role both in immune competence and self-tolerance and defects in their development and function result in immunodeficiency and/or autoimmunity. We performed a phenotypical and molecular analysis of central and peripheral B-cell compartments in WAS pediatric patients. We found a decreased proportion of immature B cells in the bone marrow correlating with an increased presence of transitional B cells in the periphery. These results could be explained by the defective migratory response of WAS B cells to SDF-1α, essential for the retention of immature B cells in the BM. In the periphery, we observed an unusual expansion of CD21low B-cell population and increased plasma BAFF levels that may contribute to the high susceptibility to develop autoimmune manifestations in WAS patients. WAS memory B cells were characterized by a reduced in vivo proliferation, decreased somatic hypermutation and preferential usage of IGHV4-34, an immunoglobulin gene commonly found in autoreactive B cells. In conclusion, our findings demonstrate that WASp-deficiency perturbs B-cell homeostasis thus adding a new layer of immune dysregulation concurring to the increased susceptibility to develop autoimmunity in WAS patients.
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Lentiviral hematopoietic stem cell gene therapy in patients with Wiskott-Aldrich Syndrome
Science, 2013Co-Authors: A. Aiuti, Samantha Scaramuzza, Francesca Ferrua, L. Biasco, M. P. Cicalese, C. Baricordi, F. Dionisio, A. Calabria, S. Giannelli, Maria Carmina CastielloAbstract:Wiskott-Aldrich Syndrome (WAS) is an inherited immunodeficiency caused by mutations in the gene encoding WASP, a protein regulating the cytoskeleton. Hematopoietic stem/progenitor cell (HSPC) transplants can be curative, but, when matched donors are unavailable, infusion of autologous HSPCs modified ex vivo by gene therapy is an alternative approach. We used a lentiviral vector encoding functional WASP to genetically correct HSPCs from three WAS patients and reinfused the cells after a reduced-intensity conditioning regimen. All three patients showed stable engraftment of WASP-expressing cells and improvements in platelet counts, immune functions, and clinical scores. Vector integration analyses revealed highly polyclonal and multilineage haematopoiesis resulting from the gene-corrected HSPCs. Lentiviral gene therapy did not induce selection of integrations near oncogenes, and no aberrant clonal expansion was observed after 20 to 32 months. Although extended clinical observation is required to establish long-term safety, lentiviral gene therapy represents a promising treatment for WAS.
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evidence for long term efficacy and safety of gene therapy for wiskott Aldrich Syndrome in preclinical models
Molecular Therapy, 2009Co-Authors: Francesco Marangoni, Sabine Charrier, Elena Draghici, Marita Bosticardo, Samantha Scaramuzza, Michela Locci, Cristina Panaroni, Maurilio Ponzoni, Francesca SanvitoAbstract:Wiskott–Aldrich Syndrome (WAS) is a life-threatening X-linked disease characterized by immunodeficiency, thrombocytopenia, autoimmunity, and malignancies. Gene therapy could represent a therapeutic option for patients lacking a suitable bone marrow (BM) donor. In this study, we analyzed the long-term outcome of WAS gene therapy mediated by a clinically compatible lentiviral vector (LV) in a large cohort of wasnull mice. We demonstrated stable and full donor engraftment and Wiskott–Aldrich Syndrome protein (WASP) expression in various hematopoietic lineages, up to 12 months after gene therapy. Importantly, we observed a selective advantage for T and B lymphocytes expressing transgenic WASP. T-cell receptor (TCR)-driven T-cell activation, as well as B-cell's ability to migrate in response to CXCL13, was fully restored. Safety was evaluated throughout the long-term follow-up of primary and secondary recipients of WAS gene therapy. WAS gene therapy did not affect the lifespan of treated animals. Both hematopoietic and nonhematopoietic tumors arose, but we excluded the association with gene therapy in all cases. Demonstration of long-term efficacy and safety of WAS gene therapy mediated by a clinically applicable LV is a key step toward the implementation of a gene therapy clinical trial for WAS.