Insights on the Multifaceted Roles of Wild-Type and Mutated Superoxide Dismutase 1 in Amyotrophic Lateral Sclerosis Pathogenesis.

Amyotrophic Lateral Sclerosis (ALS) is a progressive motor neurodegenerative disease. Cell damage in ALS is the result of many different, largely unknown, pathogenetic mechanisms. Astrocytes and microglial cells play a critical role also for their ability to enhance a deranged inflammatory response. Excitotoxicity, due to excessive glutamate levels and increased intracellular Ca2+ concentration, has also been proposed to play a key role in ALS pathogenesis/progression. Reactive Oxygen Species (ROS) behave as key second messengers for multiple receptor/ligand interactions. ROS-dependent regulatory networks are usually mediated by peroxides. Superoxide Dismutase 1 (SOD1) physiologically mediates intracellular peroxide generation. About 10% of ALS subjects show a familial disease associated with different gain-of-function SOD1 mutations. The occurrence of sporadic ALS, not clearly associated with SOD1 defects, has been also described. SOD1-dependent pathways have been involved in neuron functional network as well as in immune-response regulation. Both, neuron depolarization and antigen-dependent T-cell activation mediate SOD1 exocytosis, inducing increased interaction of the enzyme with a complex molecular network involved in the regulation of neuron functional activity and immune response. Here, alteration of SOD1-dependent pathways mediating increased intracellular Ca2+ levels, altered mitochondria functions and defective inflammatory process regulation have been proposed to be relevant for ALS pathogenesis/progression.

Differentially activated B cells develop regulatory phenotype and show varying immunosuppressive features: a comparative study.

Regulatory B lymphocytes (Bregs) are B cells with well-pronounced immunosuppressive properties, allowing them to suppress the activity of effector cells. A broad repertoire of immunosuppressive mechanisms makes Bregs an attractive tool for adoptive cell therapy for diseases associated with excessive activation of immune reactions. Such therapy implies Breg extraction from the patient's peripheral blood, ex vivo activation and expansion, and further infusion into the patient. At the same time, the utility of Bregs for therapeutic approaches is limited by their small numbers and extremely low survival rate, which is typical for all primary B cell cultures. Therefore, extracting CD19+ cells from the patient's peripheral blood and specifically activating them ex vivo to make B cells acquire a suppressive phenotype seems to be far more productive. It will allow a much larger number of B cells to be obtained initially, which may significantly increase the likelihood of successful immunosuppression after adoptive Breg transfer. This comparative study focuses on finding ways to efficiently manipulate B cells in vitro to differentiate them into Bregs. We used CD40L, CpG, IL4, IL21, PMA, and ionomycin in various combinations to generate immunosuppressive phenotype in B cells and performed functional assays to test their regulatory capacity. This work shows that treatment of primary B cells using CD40L + CpG + IL21 mix was most effective in terms of induction of functionally active regulatory B lymphocytes with high immunosuppressive capacity ex vivo.

Novel Potential Mechanisms of Regulatory B Cell-Mediated Immunosuppression.

B lymphocytes play an important role in the regulation of immune response in both normal and pathological conditions. Traditionally, the main functions of B cells were considered to be antibody production and antigen presentation, but in recent decades there have been discovered several subpopulations of regulatory B lymphocytes (Bregs), which maintain immunological tolerance and prevent overactivation of the immune system. Memory (mBregs, CD19+CD24hiCD27+) and transitional (tBregs, CD19+CD24hiCD38hi) subpopulations of Bregs are usually considered in the context of studying the role of these B cells in various human pathologies. However, the mechanisms by which these Breg subpopulations exert their immunosuppressive activity remain poorly understood. In this work, we used bioinformatic analysis of open-source RNA sequencing data to propose potential mechanisms of B cell-mediated immunosuppression. Analysis of differential gene expression before and after activation of these subpopulations allowed us to identify six candidate molecules that may determine the functionality of mBregs and tBregs. IL4I1-, SIRPA-, and SLAMF7-dependent mechanisms of immunosuppression may be characteristic of both Breg subsets, while NID1-, CST7-, and ADORA2B-dependent mechanisms may be predominantly characteristic of tBregs. In-depth understanding of the molecular mechanisms of anti-inflammatory immune response of B lymphocytes is an important task for both basic science and applied medicine and could facilitate the development of new approaches to the therapy of complex diseases.

Early innate immune response triggered by the human respiratory syncytial virus and its regulation by ubiquitination/deubiquitination processes.

The human respiratory syncytial virus (HRSV) causes severe lower respiratory tract infections in infants and the elderly. An exuberant inadequate immune response is behind most of the pathology caused by the HRSV. The main targets of HRSV infection are the epithelial cells of the respiratory tract, where the immune response against the virus begins. This early innate immune response consists of the expression of hundreds of pro-inflammatory and anti-viral genes that stimulates subsequent innate and adaptive immunity. The early innate response in infected cells is mediated by intracellular signaling pathways composed of pattern recognition receptors (PRRs), adapters, kinases, and transcriptions factors. These pathways are tightly regulated by complex networks of post-translational modifications, including ubiquitination. Numerous ubiquitinases and deubiquitinases make these modifications reversible and highly dynamic. The intricate nature of the signaling pathways and their regulation offers the opportunity for fine-tuning the innate immune response against HRSV to control virus replication and immunopathology.

[Células T reguladoras en lupus eritematoso generalizado].

El lupus eritematoso generalizado (LEG) es una enfermedad autoinmune crónica caracterizada por la pérdida de la tolerancia a los antígenos propios y la síntesis de diferentes autoanticuerpos con la formación y depósito de complejos inmunes y el daño de múltiples órganos. Las células T reguladoras (Treg) desempeñan un papel esencial en el mantenimiento de la tolerancia periférica, controlan el estado de activación del sistema inmune y limitan las respuestas autoinmunes. El estudio del número y la función de las diferentes subpoblaciones de células Treg en LEG ha sido objeto de una intensa investigación. Dependiendo del fenotipo de las células Treg analizado se ha reportado que la frecuencia de estas células en pacientes con LEG se encuentra disminuida, aumentada o sin alteraciones. Además, diferentes grupos han descrito que la función supresora de las células Treg de los pacientes con LEG se encuentra reducida o no se ve afectada. En conjunto, lo datos reportados sugieren que las células Treg desempeñan un papel relevante en la patogénesis del LEG y que estos linfocitos pueden ser considerados blancos potenciales para el diseño de nuevas estrategias terapéuticas para esta enfermedad.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by a loss of tolerance to self-antigens and synthesis of different autoantibodies, with the formation and deposition of immune complexes and damage to multiple organs. T regulatory cells (Tregs) play a crucial role in maintaining peripheral tolerance, controlling the state of activation of the immune system and limiting autoimmune responses. The study of the number and function of the different Treg cell subpopulations in SLE has been the subject of intense research. Depending on the analyzed Treg cell phenotype, the frequency of these cells has been reported to be reduced, increased or unaltered in patients with SLE. In addition, different groups have described that Treg cells suppressive function is reduced or unaffected in patients with SLE. Taken together, the reported data suggest that Treg cells play a relevant role in the pathogenesis of SLE and that these lymphocytes can be considered potential targets for the design of new therapeutic strategies for this condition.

Células T reguladoras en lupus eritematoso generalizado / Regulatory T cells in systemic lupus erythematosus

Resumen El lupus eritematoso generalizado (LEG) es una enfermedad autoinmune crónica caracterizada por la pérdida de la tolerancia a los antígenos propios y la síntesis de diferentes autoanticuerpos con la formación y depósito de complejos inmunes y el daño de múltiples órganos. Las células T reguladoras (Treg) desempeñan un papel esencial en el mantenimiento de la tolerancia periférica, controlan el estado de activación del sistema inmune y limitan las respuestas autoinmunes. El estudio del número y la función de las diferentes subpoblaciones de células Treg en LEG ha sido objeto de una intensa investigación. Dependiendo del fenotipo de las células Treg analizado se ha reportado que la frecuencia de estas células en pacientes con LEG se encuentra disminuida, aumentada o sin alteraciones. Además, diferentes grupos han descrito que la función supresora de las células Treg de los pacientes con LEG se encuentra reducida o no se ve afectada. En conjunto, lo datos reportados sugieren que las células Treg desempeñan un papel relevante en la patogénesis del LEG y que estos linfocitos pueden ser considerados blancos potenciales para el diseño de nuevas estrategias terapéuticas para esta enfermedad.

Abstract Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by a loss of tolerance to self-antigens and synthesis of different autoantibodies, with the formation and deposition of immune complexes and damage to multiple organs. T regulatory cells (Tregs) play a crucial role in maintaining peripheral tolerance, controlling the state of activation of the immune system and limiting autoimmune responses. The study of the number and function of the different Treg cell subpopulations in SLE has been the subject of intense research. Depending on the analyzed Treg cell phenotype, the frequency of these cells has been reported to be reduced, increased or unaltered in patients with SLE. In addition, different groups have described that Treg cells suppressive function is reduced or unaffected in patients with SLE. Taken together, the reported data suggest that Treg cells play a relevant role in the pathogenesis of SLE and that these lymphocytes can be considered potential targets for the design of new therapeutic strategies for this condition.

MicroRNAs That Contribute to Coordinating the Immune Response in Drosophila melanogaster.

Small noncoding RNAs called microRNAs (miRNAs) have emerged as post-transcriptional regulators of gene expression related to host defenses. Here, we have used Drosophila melanogaster to explore the contribution of individual or clusters of miRNAs in countering systemic Candida albicans infection. From a total of 72 tested, we identify 6 miRNA allelic mutant backgrounds that modulate the survival response to infection and the ability to control pathogen number. These mutants also exhibit dysregulation of the Toll pathway target transcripts Drosomycin (Drs) and Immune-Induced Molecule 1 (IM1). These are characteristics of defects in Toll signaling, and consistent with this, we demonstrate dependency for one of the miRNA mutants on the NF-κΒ homolog Dif. We also quantify changes in the miRNA expression profile over time in response to three pathogen types, and identify 13 mature miRNA forms affected by pathogens that stimulate Toll signaling. To complement this, we provide a genome-wide map of potential NF-κB sites in proximity to miRNA genes. Finally, we demonstrate that systemic C. albicans infection contributes to a reduction in the total amount of branch-chained amino acids, which is miRNA-regulated. Overall, our data reveal a new layer of miRNA complexity regulating the fly response to systemic fungal infection.