The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Synthèse et étude de composés susceptibles d'activer les cellules MAIT

MAIT cells are innate-like T lymphocytes that recognize a series of microbial antigens derived from the riboflavin (vitamin B2) biosynthesis pathway, which are exclusively present in bacteria and some yeasts. The TCR dependent activation of MAIT cells requires an antigenic presentation mediated by MR1 (MHC-class I related protein) expressed mostly by antigen presenting cells (APCs). Once activated, MAIT cells can exert antimicrobial functions notably by killing pathogen-infected cells. This antimicrobial activity suggest a strong therapeutic interest in targeting MAIT cells in innovative antimicrobial immunotherapies. Unfortunately, the most active antigen discovered yet named 5-OP-RU suffers from a high chemical instability, thus making difficult the study of MAIT cell biology. 5-OP-RU is produced from a condensation reaction between its chemical precursor 5-A-RU (also unstable) and endogenous methylglyoxal. To overcome the stability issues, we designed and synthetized stable analogues of MAIT cells trying to maintain a strong potency of MAIT cells activation. We also synthetized prodrugs of 5-A-RU that were able of releasing the molecule in situ to form 5-OP-RU directly in APCs. Finally, we developed a new clickable analogue of 5-OP-RU that can be used to track and visualize MAIT cell antigens in biological tissues and cells by fluorescence microscopy.Les cellules MAIT (mucosal-associated invariant T cells) sont des lymphocytes T de l'immunité "innate-like" capables de reconnaître des antigènes microbiens dérivés de la riboflavine (vitamine B2) qui sont produits exclusivement par des bactéries et certaines levures. L'activation des cellules MAIT dépendante du TCR nécessite une présentation antigénique par la protéine MR1 (MHC-class I related protein), celle-ci étant exprimée principalement par des cellules présentatrices d'antigènes. Une fois activées, les cellules MAIT peuvent exercer des fonctions antimicrobiennes en tuant directement les cellules infectées par un pathogène. Cette activité antimicrobienne suggère un fort intérêt thérapeutique à cibler les cellules MAIT dans des immunothérapies innovantes. Malheureusement, l'antigène le plus actif des MAIT, appelé 5-OP-RU, souffre d'une importante instabilité chimique, ce qui rend l'étude des cellules MAIT difficile. Cette molécule est produite par une réaction de condensation entre son précurseur clé, le 5-A-RU (aussi instable) et du methylglyoxal endogène. Pour résoudre le problème de l'instabilité chimique, nous avons synthétisé de nouveaux analogues stables du 5-OP-RU en cherchant à maintenir une forte activité biologique sur les cellules MAIT. Nous avons également synthétisé des prodrogues du 5-A-RU capables de libérer la molécule in situ pour former ensuite du 5-OP-RU directement dans les cellules présentatrices d'antigène. Enfin, nous avons développé un analogue "clickable" du 5-OP-RU pouvant être utilisé dans le but de suivre et de visualiser les antigènes des cellules MAIT dans les tissus biologiques et les cellules par microscopie à fluorescence

Synthesis and study of compounds able to activate MAIT cells

Les cellules MAIT (mucosal-associated invariant T cells) sont des lymphocytes T de l'immunité "innate-like" capables de reconnaître des antigènes microbiens dérivés de la riboflavine (vitamine B2) qui sont produits exclusivement par des bactéries et certaines levures. L'activation des cellules MAIT dépendante du TCR nécessite une présentation antigénique par la protéine MR1 (MHC-class I related protein), celle-ci étant exprimée principalement par des cellules présentatrices d'antigènes. Une fois activées, les cellules MAIT peuvent exercer des fonctions antimicrobiennes en tuant directement les cellules infectées par un pathogène. Cette activité antimicrobienne suggère un fort intérêt thérapeutique à cibler les cellules MAIT dans des immunothérapies innovantes. Malheureusement, l'antigène le plus actif des MAIT, appelé 5-OP-RU, souffre d'une importante instabilité chimique, ce qui rend l'étude des cellules MAIT difficile. Cette molécule est produite par une réaction de condensation entre son précurseur clé, le 5-A-RU (aussi instable) et du methylglyoxal endogène. Pour résoudre le problème de l'instabilité chimique, nous avons synthétisé de nouveaux analogues stables du 5-OP-RU en cherchant à maintenir une forte activité biologique sur les cellules MAIT. Nous avons également synthétisé des prodrogues du 5-A-RU capables de libérer la molécule in situ pour former ensuite du 5-OP-RU directement dans les cellules présentatrices d'antigène. Enfin, nous avons développé un analogue "clickable" du 5-OP-RU pouvant être utilisé dans le but de suivre et de visualiser les antigènes des cellules MAIT dans les tissus biologiques et les cellules par microscopie à fluorescence.MAIT cells are innate-like T lymphocytes that recognize a series of microbial antigens derived from the riboflavin (vitamin B2) biosynthesis pathway, which are exclusively present in bacteria and some yeasts. The TCR dependent activation of MAIT cells requires an antigenic presentation mediated by MR1 (MHC-class I related protein) expressed mostly by antigen presenting cells (APCs). Once activated, MAIT cells can exert antimicrobial functions notably by killing pathogen-infected cells. This antimicrobial activity suggest a strong therapeutic interest in targeting MAIT cells in innovative antimicrobial immunotherapies. Unfortunately, the most active antigen discovered yet named 5-OP-RU suffers from a high chemical instability, thus making difficult the study of MAIT cell biology. 5-OP-RU is produced from a condensation reaction between its chemical precursor 5-A-RU (also unstable) and endogenous methylglyoxal. To overcome the stability issues, we designed and synthetized stable analogues of MAIT cells trying to maintain a strong potency of MAIT cells activation. We also synthetized prodrugs of 5-A-RU that were able of releasing the molecule in situ to form 5-OP-RU directly in APCs. Finally, we developed a new clickable analogue of 5-OP-RU that can be used to track and visualize MAIT cell antigens in biological tissues and cells by fluorescence microscopy

Synthesis, biological evaluation and molecular modelling of new potent clickable analogues of 5-OP-RU for their use as chemical probes for the study of MAIT cell biology

International audienceMAIT cells are preset αβ T lymphocytes that recognize a series of microbial antigens exclusively derived from the riboflavin biosynthesis pathway, which is present in most bacteria. The most active known antigen is unstable 5-(2-oxopropylideneamino)-6-(d-ribitylamino)uracil (5-OP-RU) which is stabilized when bound and presented to MAIT cells by MHC-related protein 1 (MR1). Here we describe the chemical synthesis and biological evaluation of new chemical probes for the study of MAIT cell biology. The two probes were ethinyl functionalized analogues of 5-OP-RU able to react through CuAAC also called "click chemistry". The molecules up-regulated more MR1 than 5-OP-RU and they efficiently activated iVα19 Vβ8 TCR transgenic murine MAIT cells but not iVα19 TCRα transgenic MAIT cells indicating a surprisingly strong impact of the TRCβ chain. Moreover, the use of these molecules as chemical probes was validated in vitro by efficient and selective binding to MR1 revealed via fluorescence microscopy. This study was also complemented by molecular modelling investigation of the probes and the binary/ternary complexes they form with MR1 and the TCR. These new probes will be crucial to delineate the dynamics of 5-OP-RU at the cellular or whole organism level and to identify the cells presenting 5-OP-RU to MAIT cells in vivo

Protocol to expand and CRISPR-Cas9 genomic edit murine MAIT cells for subsequent in vivo studies

Summary: Generating knockout mice for target molecules in specific T cell populations, without subset-specific promoters, is time-consuming and costly. Here, we describe steps for enriching mucosal-associated invariant T cells from the thymus, expanding them in vitro and performing a CRISPR-Cas9 knockout. We then detail procedure for injecting the knockout cells into wounded Cd3ε−/− mice and characterizing them in the skin.For complete details on the use and execution of this protocol, please refer to du Halgouet et al. (2023).1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics

Role of MR1-driven signals and amphiregulin on the recruitment and repair function of MAIT cells during skin wound healing

International audienceTissue repair processes maintain proper organ function following mechanical or infection-related damage. In addition to antibacterial properties, mucosal associated invariant T (MAIT) cells express a tissue repair transcriptomic program and promote skin wound healing when expanded. Herein, we use a human-like mouse model of full-thickness skin excision to assess the underlying mechanisms of MAIT cell tissue repair function. Single-cell RNA sequencing analysis suggested that skin MAIT cells already express a repair program at steady state. Following skin excision, MAIT cells promoted keratinocyte proliferation, thereby accelerating healing. Using skin grafts, parabiosis, and adoptive transfer experiments, we show that MAIT cells migrated into the wound in a T cell receptor (TCR)-independent but CXCR6 chemokine receptor-dependent manner. Amphiregulin secreted by MAIT cells following excision promoted wound healing. Expression of the repair function was probably independent of sustained TCR stimulation. Overall, our study provides mechanistic insights into MAIT cell wound healing function in the skin

A late Neanderthal reveals genetic isolation in their populations before extinction

Summary Neanderthal genomes have been recovered from sites across Eurasia, painting an increasingly complex picture of their populations’ structure, mostly indicating that late European Neanderthals belonged to a single metapopulation with no significant evidence of deep population structure. Here we report the discovery of a late Neanderthal individual, nicknamed “Thorin”, from Grotte Mandrin in Mediterranean France, and his genome. These dentognathic fossils, including a rare example of distomolars, are associated with a rich archeological record of their final technological traditions in this region ∼50-42 thousand years ago. Thorin’s genome reveals a deep divergence with other late Neanderthals. Thorin belonged to a population with small group size that showed no genetic introgression with other known late European Neanderthals, revealing genetic isolation of his lineage despite them living in neighboring regions. These results have important implications for resolving competing hypotheses about causes of the Neanderthals’ disappearance. One Sentence Summary A new French Neanderthal fossil and its genome reveal complex population dynamics during the past 100,000 years