Wiskott-Aldrich syndrome protein regulates autophagy and inflammasome activity in innate immune cells.

Dysregulation of autophagy and inflammasome activity contributes to the development of auto-inflammatory diseases. Emerging evidence highlights the importance of the actin cytoskeleton in modulating inflammatory responses. Here we show that deficiency of Wiskott-Aldrich syndrome protein (WASp), which signals to the actin cytoskeleton, modulates autophagy and inflammasome function. In a model of sterile inflammation utilizing TLR4 ligation followed by ATP or nigericin treatment, inflammasome activation is enhanced in monocytes from WAS patients and in WAS-knockout mouse dendritic cells. In ex vivo models of enteropathogenic Escherichia coli and Shigella flexneri infection, WASp deficiency causes defective bacterial clearance, excessive inflammasome activation and host cell death that are associated with dysregulated septin cage-like formation, impaired autophagic p62/LC3 recruitment and defective formation of canonical autophagosomes. Taken together, we propose that dysregulation of autophagy and inflammasome activities contribute to the autoinflammatory manifestations of WAS, thereby identifying potential targets for therapeutic intervention

Investigating the pathogenesis of Jaki immunodeficiency

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Medicina, Departamento de Microbiología I, leída el 10-10-2019Las inmunodeficiencias primarias (IDP) son trastornos genéticos que ocasionan disfunción del sistema inmune y predisposición a infecciones. Las tecnologías de secuenciación de nueva generación han recientemente revolucionado el campo de las IDPs, identificando sus bases moleculares y orientando el diseño de nuevos tratamientos. De igual forma, el estudio de IDP monogénicas ha ayudado a descifrar el funcionamiento del sistema inmunológico, teniendo gran impacto en las áreas de autoinmunidad y cáncer. Mediante el uso de secuenciación de nueva generación, nuestro grupo ha recientemente identificado una nueva IDP asociada a mutaciones hipomórficas con pérdida de función de la proteína de señalización Janus Associated Kinase 1 (JAK1). Las manifestaciones clínicas del paciente se caracterizaron por la presencia de infecciones recurrentes por micobacterias atípicas y carcinoma transicional de vejiga de alto grado, que ocasionó el fallecimiento del paciente durante la tercera década de vida...Primary immunodeficiencies (PIDs) are genetic disorders where components of theimmune system are missing, predisposing to infection, autoimmunity and malignancy. Next generation genetic sequencing (NGS) has revolutionised the field of PIDs, identifying the molecular basis of inherited immune disorders. Using NGS, we recently reported the first description of hypomorphic loss of function mutations in human Janus Kinase 1 (JAK1) in a patient with recurrent atypical mycobacterial infections, early onset fatal high-grade urothelial carcinoma, and relatively minor viral infections. JAK1 belongs to a family of widely expressed tyrosine kinases essential for signal transduction through different cytokine receptors. Individual family members (JAK1,JAK2, JAK3 and TYK2) have non-redundant roles in cell biology. Receptor binding initiates JAK kinase activity resulting in recruitment of signal transducers and activators of transcription (STAT) proteins and transcription of responsive genes. The roles of several members of the JAK family for immune cell function have been clarified through investigation of human deficiency states and murine models...Fac. de MedicinaTRUEunpu

Loss of Janus Associated Kinase1 alters urothelial cell functionand facilitates the development of bladder cancer

Inherited Primary Immunodeficiency (PID) disorders are associated with increased risk ofmalignancy that may relate to impaired antitumor immune responses or a direct role for PIDgermline mutations in tumorigenesis. We recently identified germline loss of function mutations inJanus Associated Kinase 1 (JAK1) causing primary immunodeficiency characterised by infectionsand associated with early onset, fatal high-grade bladder carcinoma. Somatic mutations in JAK1,required for immune cell signalling in response to interferon gamma (IFNγ), have been associatedwith several non-hematopoietic and hematopoietic cancer cell types but pathogenic mechanismsremain largely unexplored. Here we demonstrate that JAK1 is required for the intrinsic IFNγresponse of urothelial cells impacting immunogenicity and cell survival. Specifically, JAK1-deficient urothelial cells showed reduced surface expression of major histocompatibility complexclass II (MHC II), intercellular adhesion molecule-1 (ICAM-1) and programmed death-ligand-1(PD-L1) after IFNγ stimulation and were resistant to IFNγ-induced apoptosis and lymphocytemediatedkilling. In addition, we identify a previously unknown role for IFNγ signalling inmodulating urothelial differentiation. Together, our findings support a role for urothelial cell JAK1in immune surveillance and development of bladder cancer. Our results have implications forpatients with rare JAK1 PID and, more broadly, inform development of biomarker and targetedtherapies for urothelial carcinoma

Partial human Janus kinase 1 deficiency predominantly impairs responses to interferon gamma and intracellular control of mycobacteria.

PURPOSE: Janus kinase-1 (JAK1) tyrosine kinase mediates signaling from multiple cytokine receptors, including interferon alpha/beta and gamma (IFN-α/β and IFN-γ), which are important for viral and mycobacterial protection respectively. We previously reported autosomal recessive (AR) hypomorphic JAK1 mutations in a patient with recurrent atypical mycobacterial infections and relatively minor viral infections. This study tests the impact of partial JAK1 deficiency on cellular responses to IFNs and pathogen control. METHODS: We investigated the role of partial JAK1 deficiency using patient cells and cell models generated with lentiviral vectors expressing shRNA. RESULTS: Partial JAK1 deficiency impairs IFN-γ-dependent responses in multiple cell types including THP-1 macrophages, Epstein-Barr Virus (EBV)-transformed B cells and primary dermal fibroblasts. In THP-1 myeloid cells, partial JAK1 deficiency reduced phagosome acidification and apoptosis and resulted in defective control of mycobacterial infection with enhanced intracellular survival. Although both EBV-B cells and primary dermal fibroblasts with partial JAK1 deficiency demonstrate reduced IFN-α responses, control of viral infection was impaired only in patient EBV-B cells and surprisingly intact in patient primary dermal fibroblasts. CONCLUSION: Our data suggests that partial JAK1 deficiency predominantly affects susceptibility to mycobacterial infection through impact on the IFN-γ responsive pathway in myeloid cells. Susceptibility to viral infections as a result of reduced IFN-α responses is variable depending on cell type. Description of additional patients with inherited JAK1 deficiency will further clarify the spectrum of bacterial and viral susceptibility in this condition. Our results have broader relevance for anticipating infectious complications from the increasing use of selective JAK1 inhibitors

Sequential administration of paricalcitol followed by IL-17 blockade for progressive refractory IgA nephropathy patients

Abstract There is no established treatment for progressive IgA nephropathy refractory to steroids and immunosuppressant drugs (r-IgAN). Interleukin 17 (IL-17) blockade has garnered interest in immune-mediated diseases involving the gut-kidney axis. However, single IL-17A inhibition induced paradoxical effects in patients with Crohn’s disease and some cases of de novo glomerulonephritis, possibly due to the complete Th1 cell response, along with the concomitant downregulation of regulatory T cells (Tregs). Seven r-IgAN patients were treated with at least six months of oral paricalcitol, followed by the addition of subcutaneous anti-IL-17A (secukinumab). After a mean follow-up of 28 months, proteinuria decreased by 71% (95% CI: 56–87), P < 0.001. One patient started dialysis, while the annual eGFR decline in the remaining patients [mean (95% CI)] was reduced by 4.9 mL/min/1.73 m2 (95% CI: 0.1–9.7), P = 0.046. Circulating Th1, Th17, and Treg cells remained stable, but Th2 cells decreased, modifying the Th1/Th2 ratio. Intriguingly, accumulation of circulating Th17.1 cells was observed. This novel sequential therapy appears to optimize renal advantages in patients with r-IgAN and elicit alterations in potentially pathogenic T helper cells

Natural Killer Cells from Patients with Recombinase-Activating Gene and Non-Homologous End Joining Gene Defects Comprise a Higher Frequency of CD56bright NKG2A+++ Cells, and Yet Display Increased Degranulation and Higher Perforin Content.

Mutations of the recombinase-activating genes 1 and 2 (RAG1 and RAG2) in humans are associated with a broad range of phenotypes. For patients with severe clinical presentation, hematopoietic stem cell transplantation (HSCT) represents the only curative treatment; however, high rates of graft failure and incomplete immune reconstitution have been observed, especially after unconditioned haploidentical transplantation. Studies in mice have shown that Rag-/- natural killer (NK) cells have a mature phenotype, reduced fitness, and increased cytotoxicity. We aimed to analyze NK cell phenotype and function in patients with mutations in RAG and in non-homologous end joining (NHEJ) genes. Here, we provide evidence that NK cells from these patients have an immature phenotype, with significant expansion of CD56bright CD16-/int CD57- cells, yet increased degranulation and high perforin content. Correlation was observed between in vitro recombinase activity of the mutant proteins, NK cell abnormalities, and in vivo clinical phenotype. Addition of serotherapy in the conditioning regimen, with the aim of depleting the autologous NK cell compartment, may be important to facilitate engraftment and immune reconstitution in patients with RAG and NHEJ defects treated by HSCT

Natural Killer Cells from Patients with Recombinase-Activating Gene and Non-Homologous End Joining Gene Defects Comprise a Higher Frequency of CD56(bright) NKG2A(+++) Cells, and Yet Display Increased Degranulation and Higher Perforin Content

Mutations of the recombinase-activating genes 1 and 2 (RAG1 and RAG2) in humans are associated with a broad range of phenotypes. For patients with severe clinical presentation, hematopoietic stem cell transplantation (HSCT) represents the only curative treatment; however, high rates of graft failure and incomplete immune reconstitution have been observed, especially after unconditioned haploidentical transplantation. Studies in mice have shown that Rag(-/-) natural killer (NK) cells have a mature phenotype, reduced fitness, and increased cytotoxicity. We aimed to analyze NK cell phenotype and function in patients with mutations in RAG and in non-homologous end joining (NHEJ) genes. Here, we provide evidence that NK cells from these patients have an immature phenotype, with significant expansion of CD56(bright) CD16(-/int) CD57(-) cells, yet increased degranulation and high perforin content. Correlation was observed between in vitro recombinase activity of the mutant proteins, NK cell abnormalities, and in vivo clinical phenotype. Addition of serotherapy in the conditioning regimen, with the aim of depleting the autologous NK cell compartment, may be important to facilitate engraftment and immune reconstitution in patients with RAG and NHEJ defects treated by HSCT.status: publishe

Corrigendum: Natural Killer Cells from Patients with Recombinase-Activating Gene and Non-Homologous End Joining Gene Defects Comprise a Higher Frequency of CD56bright NKG2A+++ Cells, and Yet Display Increased Degranulation and Higher Perforin Content

[This corrects the article on p. 798 in vol. 8, PMID: 28769923.].status: publishe