Activin-A limits Th17 pathogenicity and autoimmune neuroinflammation via CD39 and CD73 ectonucleotidases and Hif1-α–dependent pathways

In multiple sclerosis (MS), Th17 cells are critical drivers of autoimmune central nervous system (CNS) inflammation and demyelination. Th17 cells exhibit functional heterogeneity fostering both pathogenic and nonpathogenic, tissue-protective functions. Still, the factors that control Th17 pathogenicity remain incompletely defined. Here, using experimental autoimmune encephalomyelitis, an established mouse MS model, we report that therapeutic administration of activin-A ameliorates disease severity and alleviates CNS immunopathology and demyelination, associated with decreased activation of Th17 cells. In fact, activin-A signaling through activin-like kinase-4 receptor represses pathogenic transcriptional programs in Th17-polarized cells, while it enhances antiinflammatory gene modules. Whole-genome profiling and in vivo functional studies revealed that activation of the ATP-depleting CD39 and CD73 ectonucleotidases is essential for activin-A–induced suppression of the pathogenic signature and the encephalitogenic functions of Th17 cells. Mechanistically, the aryl hydrocarbon receptor, along with STAT3 and c-Maf, are recruited to promoter elements on Entpd1 and Nt5e (encoding CD39 and CD73, respectively) and other antiinflammatory genes, and control their expression in Th17 cells in response to activin-A. Notably, we show that activin-A negatively regulates the metabolic sensor, hypoxia-inducible factor-1α, and key inflammatory proteins linked to pathogenic Th17 cell states. Of translational relevance, we demonstrate that activin-A is induced in the CNS of individuals with MS and restrains human Th17 cell responses. These findings uncover activin-A as a critical controller of Th17 cell pathogenicity that can be targeted for the suppression of autoimmune CNS inflammation

Activin-A co-opts IRF4 and AhR signaling to induce human regulatory T cells that restrain asthmatic responses

Type 1 regulatory T (Tr1) cells play a pivotal role in restraining human T-cell responses toward environmental allergens and protecting against allergic diseases. Still, the precise molecular cues that underlie their transcriptional and functional specification remain elusive. Here, we show that the cytokine activin-A instructs the generation of CD4+ T cells that express the Tr1-cell–associated molecules IL-10, inducible T-Cell costimulator (ICOS), lymphocyte activation gene 3 protein (LAG-3), and CD49b, and exert strongly suppressive functions toward allergic responses induced by naive and in vivo-primed human T helper 2 cells. Moreover, mechanistic studies reveal that activin-A signaling induces the activation of the transcription factor interferon regulatory factor (IRF4), which, along with the environmental sensor aryl hydrocarbon receptor, forms a multipartite transcriptional complex that binds in IL-10 and ICOS promoter elements and controls gene expression in human CD4+ T cells. In fact, IRF4 silencing abrogates activin-A– driven IL10 and ICOS up-regulation and impairs the suppressive functions of human activin-A–induced Tr1-like (act-A–iTr1) cells. Importantly, using a humanized mouse model of allergic asthma, we demonstrate that adoptive transfer of human act-A–iTr1 cells, both in preventive and therapeutic protocols, confers significant protection against cardinal asthma manifestations, including pulmonary inflammation. Overall, our findings uncover an activin-A–induced IRF4-aryl hydrocarbon receptor (AhR)–dependent transcriptional network, which generates suppressive human Tr1 cells that may be harnessed for the control of allergic diseases

A study of the role of foamy viral vectors expressing anti-α globin shRNA (short hairpin RNA) and β-globin in experimental models of thalassemia

Therapeutic β-globin vectors have been constructed and tested for over two decades as an alternative treatment options for β-thalassemia. In order to test the efficiency of β-globin expression from our FV vectors we transduced cells of the MEL line, primary hematopoietic progenitors from a thalassemic mouse model as well as from human β-thalassemia patients. We demonstrate that while both FV vectors can produce human β-globin at levels that can ameliorate the ineffective erythropoiesis seen in thalassemic cells, the HS40 element is marginally more efficient than the combination of HS2/HS3, both ex vivo in murine HSCs and human CD34⁺ cells, as well as in the mouse model of β-thalassemia. Given the compact size of the HS40 element, we propose that it can be used alternatively to the LCR sequences for regulated β-globin expression in gene therapy approaches with FV vectors. Another goal of this study is to create FV vectors that co-express the β-globin gene alongside with a shorthairpin RNA against the α-globin gene in order to achieve a more efficient restoration of the β- to α-globin imbalance. The result was that the combined FV vector achieved more efficient restoration of the distorted erythropoiesis observed in thalassemic cells and in comparison to the single vectors.Οι γενετικού τύπου θεραπευτικές προσεγγίσεις της β-θαλασσαιμίας αποτελούν μία εναλλακτική στρατηγική που σαν σκοπό έχουν την μεταφορά του γονιδίου της β-σφαιρίνης στα αρχέγονα αιμοποιητικά κύτταρα και την έκφραση της αιμοσφαιρίνης στα ώριμα ερυθροκύτταρα. Στη μελέτη μας χρησιμοποιήσαμε αφροϊικούς φορείς με την ρυθμιστική αλληλουχία HS40 καθώς επίσης και τις ρυθμιστικές αλληλουχίες HS2 και HS3 ώστε να εκφράζουν αποδοτικά το γονίδιο της β-σφαιρίνης. Μετά από μεταγωγή της κυτταρικής σειράς MEL, αρχέγονων αιμοποιητικών κυττάρων από πειραματικό μοντέλο β-θαλασσαιμίας ποντικού καθώς και αρχέγονων αιμοποιητικών κυττάρων από ασθενείς με β-θαλασσαιμίας προέκυψε ότι και οι δύο φορείς είναι ικανοί να παράγουν αποδοτικά το γονίδιο της β-σφαιρίνης σε επίπεδα που κρίνονται επαρκή για να οδηγήσουν σε φυσιολογική αιμοποίηση. Ο φορέας που χρησιμοποιεί την αλληλουχία HS40 εμφανίστηκε οριακά πιο σταθερός και περισσότερο αποδοτικός στην έκφραση της β-σφαιρίνης μετά από μεταμόσχευση στο μοντέλο της β-θαλασσαιμίας του ποντικού. Συγχρόνως ελέγχθηκε και μια συνδυαστική κατασκευή που εκφράζει το γονίδιο της β-σφαιρίνης μαζί με μία μικρή φουρκέτα RNA ενάντια στο γονίδιο της α-σφαιρίνης. Η συνδυαστική κατασκευή κρίθηκε περισσότερο αποτελεσματική στην αποκατάσταση της μη-αποδοτικής ερυθροποίησης των θαλασσαιμικών αρχέγονων κυττάρων

Dendritic Cells: Critical Regulators of Allergic Asthma

Allergic asthma is a chronic inflammatory disease of the airways characterized by airway hyperresponsiveness (AHR), chronic airway inflammation, and excessive T helper (Th) type 2 immune responses against harmless airborne allergens. Dendritic cells (DCs) represent the most potent antigen-presenting cells of the immune system that act as a bridge between innate and adaptive immunity. Pertinent to allergic asthma, distinct DC subsets are known to play a central role in initiating and maintaining allergen driven Th2 immune responses in the airways. Nevertheless, seminal studies have demonstrated that DCs can also restrain excessive asthmatic responses and thus contribute to the resolution of allergic airway inflammation and the maintenance of pulmonary tolerance. Notably, the transfer of tolerogenic DCs in vivo suppresses Th2 allergic responses and protects or even reverses established allergic airway inflammation. Thus, the identification of novel DC subsets that possess immunoregulatory properties and can efficiently control aberrant asthmatic responses is critical for the re-establishment of tolerance and the amelioration of the asthmatic disease phenotype

Severe Asthmatic Responses: The Impact of TSLP

Asthma is a chronic inflammatory disease that affects the lower respiratory system and includes several categories of patients with varying features or phenotypes. Patients with severe asthma (SA) represent a group of asthmatics that are poorly responsive to medium-to-high doses of inhaled corticosteroids and additional controllers, thus leading in some cases to life-threatening disease exacerbations. To elaborate on SA heterogeneity, the concept of asthma endotypes has been developed, with the latter being characterized as T2-high or low, depending on the type of inflammation implicated in disease pathogenesis. As SA patients exhibit curtailed responses to standard-of-care treatment, biologic therapies are prescribed as adjunctive treatments. To date, several biologics that target specific downstream effector molecules involved in disease pathophysiology have displayed superior efficacy only in patients with T2-high, eosinophilic inflammation, suggesting that upstream mediators of the inflammatory cascade could constitute an attractive therapeutic approach for difficult-to-treat asthma. One such appealing therapeutic target is thymic stromal lymphopoietin (TSLP), an epithelial-derived cytokine with critical functions in allergic diseases, including asthma. Numerous studies in both humans and mice have provided major insights pertinent to the role of TSLP in the initiation and propagation of asthmatic responses. Undoubtedly, the magnitude of TSLP in asthma pathogenesis is highlighted by the fact that the FDA recently approved tezepelumab (Tezspire), a human monoclonal antibody that targets TSLP, for SA treatment. Nevertheless, further research focusing on the biology and mode of function of TSLP in SA will considerably advance disease management

Targeting NLRP3 Inflammasome Activation in Severe Asthma

Severe asthma (SA) is a chronic lung disease characterized by recurring symptoms of reversible airflow obstruction, airway hyper-responsiveness (AHR), and inflammation that is resistant to currently employed treatments. The nucleotide-binding oligomerization domain-like Receptor Family Pyrin Domain Containing 3 (NLRP3) inflammasome is an intracellular sensor that detects microbial motifs and endogenous danger signals and represents a key component of innate immune responses in the airways. Assembly of the NLRP3 inflammasome leads to caspase 1-dependent release of the pro-inflammatory cytokines IL-1β and IL-18 as well as pyroptosis. Accumulating evidence proposes that NLRP3 activation is critically involved in asthma pathogenesis. In fact, although NLRP3 facilitates the clearance of pathogens in the airways, persistent NLRP3 activation by inhaled irritants and/or innocuous environmental allergens can lead to overt pulmonary inflammation and exacerbation of asthma manifestations. Notably, administration of NLRP3 inhibitors in asthma models restrains AHR and pulmonary inflammation. Here, we provide an overview of the pathophysiology of SA, present molecular mechanisms underlying aberrant inflammatory responses in the airways, summarize recent studies pertinent to the biology and functions of NLRP3, and discuss the role of NLRP3 in the pathogenesis of asthma. Finally, we contemplate the potential of targeting NLRP3 as a novel therapeutic approach for the management of SA

Απεικόνιση επιταχυντών συστημάτων υψηλής απόδοσης στην πλατφόρμα HARP2 χρησιμοποιώντας την αρχιτεκτονική αποζευγμένης επεξεργασίας και πρόσβασης δεδομένων DAER

Summarization: In the latest years, the need to process large volumes of data in a short period and the need to limit the power consumption, have shifted the computing industry vendors to build High-Performance Computing (HPC) acceleration platforms. The hybrid CPU-FPGA (Field-Programmable Gate Arrays) system is one of the most promising HPC platforms because FPGAs provide reconfigurability to accelerate different applications, faster processing, and more power-efficient and lower latency service. In these platforms, the CPU and the FPGA are tightly coupled with each other and share the same DRAM for better communication. The platform used in this work is the Intel© Xeon© Scalable Platform with Integrated FPGA (HARP2 Platform). The Decoupled Access/Execute framework is a new way of mapping algorithms efficiently on Reconfigurable platforms (DAER). This framework splits the application tasks into two parts, the data processing (Process Unit) and the data fetching (Fetch Unit). This division completely decouples access to memory by processing data, to achieve high performance by exploiting parallelism. This Diploma Thesis aims to implement the Jacobi algorithm with the DAER framework in the HARP platform for the solution of Laplace equations. The Jacobi method belongs to the Structured Grid algorithms that fall into the list of thirteen (13) Dwarfs that represent active areas in parallel computing. In this work, two architectures have been mapped to try to exploit the advantages of the DAER framework. The experiments were conducted in the Academic Compute Environment (ACE) that is located on the vLabs of Intel. The results of those experiments show that using the DAER framework in the Hybrid CPU-FPGA platform achieves up to 2x speed-up compared to the CPU-based solution.Περίληψη: Τα τελευταία χρόνια, η ανάγκη επεξεργασίας μεγάλου όγκου δεδομένων σε σύντομο χρονικό διάστημα και η ανάγκη περιορισμού της κατανάλωσης ενέργειας, έχουν υποκινήσει τη βιομηχανία του κλάδου των υπολογιστών να δημιουργήσει πλατφόρμες επιταχυντών υψηλής απόδοσης (HPC). Τα υβριδικά συστήματα CPU-FPGA είναι από τις πιο ελπιδοφόρες πλατφόρμες υψηλής απόδοσης, επειδή οι FPGA παρέχουν δυνατότητα αναδιάταξης για την επιτάχυνση διαφορετικών εφαρμογών, ταχύτερη επεξεργασία και πιο αποδοτική και ταχύτερη μεταφορά δεδομένων. Σε αυτές τις πλατφόρμες, η CPU και η FPGA συνδέονται στενά μεταξύ τους και μοιράζονται την ίδια μνήμη DRAM επιτυγχάνοντας καλύτερη επικοινωνία. Η πλατφόρμα που χρησιμοποιείται σε αυτήν την εργασία είναι η Intel © Xeon © Scalable Platform με ενσωματωμένη FPGA (HARP2 Platform). Η αρχιτεκτονική αποζευγμένης επεξεργασίας και πρόσβασης δεδομένων είναι ένας νέος, αποτελεσματικός τρόπος απεικόνισης αλγόριθμων σε αναδιατασσόμενες πλατφόρμες (DAER). Αυτή η αρχιτεκτονική χωρίζει τις εργασίες της εφαρμογής σε δύο μέρη, την επεξεργασία δεδομένων (μονάδα επεξεργασίας) και την ανάκτηση δεδομένων (μονάδα ανάκτησης). Αυτός ο διαχωρισμός ελαχιστοποιεί την εξάρτηση της πρόσβασης στη μνήμη με την επεξεργασία των δεδομένων, επιτυγχάνοντας υψηλή απόδοση αξιοποιώντας τον παραλληλισμό. Αυτή η εργασία, έχει ως στόχο την απεικόνιση του αλγόριθμου Jacobi στη πλατφόρμα HARP με την χρήση της αρχιτεκτονικής DAER για την λύση εξισώσεων Laplace. Η μέθοδος Jacobi ανήκει στους αλγόριθμους δομημένων πλεγμάτων που περιλαμβάνονται στη λίστα των 13 νάνων, οι οποίοι αντιπροσωπεύουν ενεργές περιοχές στον παράλληλο προγραμματισμό. Σε αυτή την εργασία, έχουν χαρτογραφηθεί δύο αρχιτεκτονικές που προσπαθούν να εκμεταλλευτούν τα πλεονεκτήματα της αρχιτεκτονικής DAER. Τα πειράματα διεξήχθησαν στο Academic Compute Environment (ACE) που βρίσκεται στο vLabs της Intel. Τα αποτελέσματα αυτών των πειραμάτων δείχνουν ότι η χρήση της αρχιτεκτονικής DAER στη υβριδική πλατφόρμα CPU-FPGA επιτυγχάνει μέχρι και 2x επιτάχυνση της απόδοσης σε σύγκριση με την λύση που βασίζεται μόνο στην CPU

Activin-A co-opts IRF4 and AhR signaling to induce human regulatory T cells that restrain asthmatic responses

Type 1 regulatory T (Tr1) cells play a pivotal role in restraining human T-cell responses toward environmental allergens and protecting against allergic diseases. Still, the precise molecular cues that underlie their transcriptional and functional specification remain elusive. Here, we show that the cytokine activin-A instructs the generation of CD4(+) T cells that express the Tr1-cell–associated molecules IL-10, inducible T-Cell costimulator (ICOS), lymphocyte activation gene 3 protein (LAG-3), and CD49b, and exert strongly suppressive functions toward allergic responses induced by naive and in vivo-primed human T helper 2 cells. Moreover, mechanistic studies reveal that activin-A signaling induces the activation of the transcription factor interferon regulatory factor (IRF4), which, along with the environmental sensor aryl hydrocarbon receptor, forms a multipartite transcriptional complex that binds in IL-10 and ICOS promoter elements and controls gene expression in human CD4(+) T cells. In fact, IRF4 silencing abrogates activin-A–driven IL10 and ICOS up-regulation and impairs the suppressive functions of human activin-A–induced Tr1-like (act-A–iTr1) cells. Importantly, using a humanized mouse model of allergic asthma, we demonstrate that adoptive transfer of human act-A–iTr1 cells, both in preventive and therapeutic protocols, confers significant protection against cardinal asthma manifestations, including pulmonary inflammation. Overall, our findings uncover an activin-A–induced IRF4-aryl hydrocarbon receptor (AhR)–dependent transcriptional network, which generates suppressive human Tr1 cells that may be harnessed for the control of allergic diseases