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Memory B-cell dysfunctions and inefficient antibody response suggest germinal center (GC) impairments during HIV/SIV infection with possible contribution of overproduced B-cell activating factor (BAFF). To address this question, we compared proportions and functions of various B-cell subsets and follicular helper T-cells (TFH) in untreated (Placebo) and BR3-Fc treated (Treated) SIV-infected macaques. From day 2 post-infection (dpi), Treated macaques received one weekly injection of BR3-Fc molecule, a soluble BAFF antagonist, for 4 weeks. Whereas, the kinetics of CD4+ T-cell loss and plasma viral loads were comparable in both groups, BAFF blockade delayed the peak of inflammatory cytokines (CXCL10, IFNα), impaired the renewal of plasmacytoid dendritic cells and fostered the decline of plasma CXCL13 titers after 14 dpi. In Treated macaques, proportions of total and naive B-cells were reduced in blood and spleen whereas SIV-induced loss of marginal zone (MZ) B-cells was only accentuated in blood and terminal ileum. Proportions of spleen GC B-cells and TFH were similar in both groups, with CD8+ T-cells and rare Foxp3+ being present in spleen GC. Regardless of treatment, sorted TFH produced similar levels of IL21, CXCL13, and IFNγ but no IL2, IL4, or BAFF and exhibited similar capacities to support IgG production by autologous or heterologous B-cells. Consistently, most TFH were negative for BAFF-R and TACI. Higher proportions of resting and atypical (CD21lo) memory B-cells were present in Treated macaques compared to Placebo. In both groups, we found higher levels of BAFF-R expression on MZ and resting memory B-cells but low levels on atypical memory B-cells. TACI was present on 20-30% of MZ, resting and atypical memory B-cells in Placebo macaques. BAFF blockade decreased TACI expression on these B-cell subsets as well as titers of SIV-specific and vaccine-specific antibodies arguing for BAFF being mandatory for plasma cell survival. Irrespective of treatment, GC B-cells expressed BAFF-R at low level and were negative for TACI. In addition to key information on spleen BAFF-R and TACI expression, our data argue for BAFF contributing to the GC reaction in terminal ileum but being dispensable for the generation of atypical memory B-cells and GC reaction in spleen during T-dependent response against SIV.

Internal tandem duplication in Fms-like tyrosine kinase 3 (FLT3-ITD) is the most frequent mutation observed in acute myeloid leukemia (AML) and correlates with poor prognosis. FLT3 tyrosine kinase inhibitors are promising for targeted therapy. Here, we investigated mechanisms dampening the response to the FLT3 inhibitor quizartinib, which is specific to the hematopoietic niche. Using AML primary samples and cell lines, we demonstrate that convergent signals from the hematopoietic microenvironment drive FLT3-ITD cell resistance to quizartinib through the expression and activation of the tyrosine kinase receptor AXL. Indeed, cytokines sustained phosphorylation of the transcription factor STAT5 in quizartinib-treated cells, which enhanced AXL expression by direct binding of a conserved motif in its genomic sequence. Likewise, hypoxia, another well-known hematopoietic niche hallmark, also enhanced AXL expression. Finally, in a xenograft mouse model, inhibition of AXL significantly increased the response of FLT3-ITD cells to quizartinib exclusively within a bone marrow environment. These data highlight a new bypass mechanism specific to the hematopoietic niche that hampers the response to quizartinib through combined upregulation of AXL activity. Targeting this signaling offers the prospect of a new therapy to eradicate resistant FLT3-ITD leukemic cells hidden within their specific microenvironment, thereby preventing relapses from FLT3-ITD clones.

OCRL mutations are associated with both Lowe syndrome and Dent-2 disease, two rare X-linked conditions. Lowe syndrome is an oculo-cerebro-renal disorder, whereas Dent-2 patients mainly present renal proximal tubulopathy. Loss of OCRL-1, a phosphoinositide-5-phosphatase, leads in Lowe patients' fibroblasts to phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) accumulation, with defects in F-actin network, α-actinin distribution and ciliogenesis, whereas fibroblasts of Dent-2 patients are still uncharacterized. To search for mechanisms linked to clinical variability observed between these two OCRL mutation-associated pathologies, we compared dermal fibroblasts from independent patients, four affected by Dent-2 disease and six with Lowe syndrome. For the first time, we describe that Dent-2 fibroblasts with OCRL loss-of-function (LOF) mutations exhibit decrease in actin stress fibers, appearance of punctate α-actinin signals and alteration in primary cilia formation. Interestingly, we quantified these phenotypes as clearly intermediate between Lowe and control fibroblasts, thus suggesting that levels of these defects correlate with clinical variations observed between patients with OCRL mutations. In addition, we show that Lowe and Dent-2 fibroblasts display similar PI(4,5)P2 accumulation levels. Finally, we analyzed INPP5B, a paralogous gene already reported to exhibit functional redundancy with OCRL, and report neither differences in its expression at RNA or protein levels, nor specific allelic variations between fibroblasts of patients. Altogether, we describe here differential phenotypes between fibroblasts from Lowe and Dent-2 patients, both associated with OCRL LOF mutations, we exclude direct roles of PI(4,5)P2 and INPP5B in this phenotypic variability and we underline potential key alterations leading to ocular and neurological clinical features in Lowe syndrome.

To investigate the impact of antiretroviral treatment on the mitochondrial DNA (mtDNA) content of peripheral blood mononuclear cells (PBMCs) from HIV-1-infected patients.As absolute mtDNA copy numbers widely differ between individuals, we performed a longitudinal analysis where the patient's first historical specimen was obtained as a baseline reference for relative comparison with subsequent samples from that patient.mtDNA and nuclear DNA quantitation per cell (beta-globin gene copies) were both measured by real-time polymerase chain reaction analysis of whole DNA extracts of 361 serial live-cryopreserved PBMCs collected in former trials and clinical follow-ups from 60 individuals with established or recently acquired HIV-1 infections before and during administration of various antiviral combination therapies.mtDNA amounts were stable or increasing over years of natural HIV-1 infection in untreated patients (n = 7), consistent with our finding of a lack of differences in mtDNA copy numbers in patients with either a long established or recent lentivirus infection. Our quantitation system revealed significant changes in mtDNA copy number depending on the designated triple, quadruple, or quintuple anti-HIV drug combinations. Zidovudine + zalcitabine + ritonavir and zidovudine + lamivudine + didanosine regularly lead to mtDNA depletion in each of the treated patients, whereas none of 7 patients (and 35 cell specimens) receiving a stavudine + lamivudine + indinavir combination had any significant mtDNA content variations. In 7 patients, mtDNA copy numbers returned to pretreatment levels and/or higher levels without any interruption of the previously mtDNA-depleting antiretroviral drug combination.Our assay system allowed the detection of significant changes in the mtDNA content of PBMCs from HIV-1-infected patients taking antiretroviral drugs, as has been reported in the literature with other detection systems. Yet, mtDNA copy numbers regularly diminished during administration of some but not all nucleoside analog-containing combinations. This, plus the occasional finding that depleted mtDNA contents spontaneously increased to baseline levels and/or higher levels during uninterrupted treatment, should raise a note of caution about resorting to the PBMC mtDNA marker for monitoring of antiretroviral drug-related mitochondrial toxicities.

ARMC5 (Armadillo repeat containing 5 gene) was identified as a new tumor suppressor gene responsible for hereditary adrenocortical tumors and meningiomas. ARMC5 is ubiquitously expressed and encodes a protein which contains a N-terminal Armadillo repeat domain and a C-terminal BTB (Bric-a-Brac, Tramtrack and Broad-complex) domain, both docking platforms for numerous proteins. At present, expression regulation and mechanisms of action of ARMC5 are almost unknown. In this study, we showed that ARMC5 interacts with CUL3 requiring its BTB domain. This interaction leads to ARMC5 ubiquitination and further degradation by the proteasome. ARMC5 alters cell cycle (G1/S phases and cyclin E accumulation) and this effect is blocked by CUL3. Moreover, missense mutants in the BTB domain of ARMC5, identified in patients with multiple adrenocortical tumors, are neither able to interact and be degraded by CUL3/proteasome nor alter cell cycle. These data show a new mechanism of regulation of the ARMC5 protein and open new perspectives in the understanding of its tumor suppressor activity.

International audience; ObjectivesTo provide clinical practice guidelines about fertility preservation (FP) for women with benign gynecologic disease (BGD) developed by a modified Delphi consensus process for oocyte vitrification in women with benign gynecologic disease.MethodsA steering committee composed of 14 healthcare professionals and a patient representative with lived experience of endometriosis identified 42 potential practices related to FP for BGD. Then 114 key stakeholders including various healthcare professionals (n = 108) and patient representatives (n = 6) were asked to participate in a modified Delphi process via two online survey rounds from February to September 2020 and a final meeting. Due to the COVID-19 pandemic, this final meeting to reach consensus was held as a videoconference in November 2020.ResultsSurvey response of stakeholders was 75 % (86/114) for round 1 and 87 % (75/86) for round 2. Consensus was reached for the recommendations for 28 items, that have been distributed into five general categories: (i) Information to provide to women of reproductive age with a BGD, (ii) Technical aspects of FP for BGD, (iii) Indications for FP in endometriosis, (iv) Indications for FP for non-endometriosis BGD, (v) Indications for FP after a fortuitous diagnosis of an idiopathic diminished ovarian reserve.ConclusionThese guidelines provide some practice advice to help health professionals better inform women about the possibilities of cryopreserving their oocytes prior to the management of a BGD that may affect their ovarian reserve and fertility.; ObjectifsÉlaborer des conseils de bonnes pratiques sous l’égide du CNGOF pour préserver la fertilité des femmes devant être prise en charge pour une pathologie gynécologique bénigne risquant d’altérer la fertilité.MéthodesUn comité de pilotage composé de 14 médecins et d’une représentante d’association de patientes a identifié dans un premier temps 42 propositions de conseils de bonne pratique, qui ont ensuite été soumis à l’expertise de 108 médecins experts Francophones provenant de différentes spécialités et de 6 représentantes d’association de patientes. Les 2 tours de Delphi ont été réalisés en ligne entre février et septembre 2020 avec une réunion finale de concertation en visioconférence en novembre 2020.RésultatsLe taux de participation a été de 75 % (86/114) au 1er tour et 87 % (75/86) au 2e tour. Au total, 28 conseils de bonnes pratiques ont été retenus par le panel d’experts après consensus Delphi et ont été réparties en 5 thématiques : (i) Information à donner aux femmes en âge de procréer devant être traitées pour une pathologie gynécologique bénigne, (ii) aspects techniques de la préservation de la fertilité pour les pathologies gynécologique bénignes, (iii) indications de préservation de la fertilité dans le cadre de l’endométriose, (iv) indications de préservation de la fertilité dans les pathologies gynécologiques bénignes hors endométriose, (v) indications de préservation de la fertilité en cas de découverte fortuite d’une diminution idiopathique de la réserve ovarienne.ConclusionCette étude Delphi a permis de dégager des conseils de bonne pratique afin d’aider les professionnels de santé à mieux informer les femmes sur les possibilités de préserver leurs ovocytes avant prise en charge d’une pathologie gynécologique risquant d’altérer leur fertilité.

Liver hepcidin, is well recognized as the central hormone of systemic iron regulation. Although serotonin is most recognized as a brain neurotransmitter, prodigious quantities are synthesized in gut enterochromaffin cells and several lines of evidence, also identified the gut as an essential sensor and regulator of iron homeostasis. Using a mouse model deficient for peripheral serotonin (Tph1 KO), we identified gut-derived serotonin as a key physiological factor in hepcidin regulation. Serotonin represses hepcidin’s through a 5HT2B receptor-dependent pathway, independently of any other known hepcidin regulators, including bone marrow signals. This regulation is conserved in humans and shows physiological significance as a negative correlation between serotonin and hepcidin levels was observed in a cohort of healthy individuals. Moreover, in pathological situation such as acute heart failure, where iron deficiency has a negative prognostic impact, we provide evidence that an increase in serotonin level seems necessary to repress hepcidin level, to increase iron availability.

Background JC polyomavirus (JCV) mostly causes asymptomatic persistent renal infections but may give rise in immunosuppressed patients to neurotropic variants that replicate in the brain, causing progressive multifocal leukoencephalopathy (PML). Rearrangements in the JCV genome regulator noncoding control region (NCCR) and missense mutations in the viral capsid VP1 gene differentiate neurotropic variants from virus excreted in urine. Methods To investigate intrahost emergence of JCV neurotropic populations in PML, we deep sequenced JCV whole genome recovered from cerebrospinal fluid (CSF) and urine samples from 32 human immunodeficiency virus (HIV)–infected and non-HIV-infected PML patients at the single-molecule level. Results JCV strains distributed among 6 of 7 known genotypes. Common patterns of NCCR rearrangements included an initial deletion mostly located in a short 10-nucleotide sequence, followed by duplications/insertions. Multiple NCCR variants present in individual CSF samples shared at least 1 rearrangement, suggesting they stemmed from a unique viral population. NCCR variants independently acquired single or double PML-specific adaptive VP1 mutations. NCCR variants recovered from urine and CSF displayed opposite deletion or duplication patterns in binding sites for transcription factors. Conclusions Long-read deep sequencing shed light on emergence of neurotropic JCV populations in PML.

Session 1: Impact of diet and additives on gut microbiota and health ; Communication PO24; International audience; Since several decades, lifestyle and nutrition changes (unbalance in lipid intake quality) in the developed countries has leaded to the increased prevalence of inflammatory and metabolic pathologies. These pathologies are associated with an increase in visceral adipose tissue, chronic low-grade inflammation and a gut microbiota dysbiosis. Long-term habits play a crucial role on the gut microbiota community and diversity of these bacterial communities. General population is in deficit in n-3 PUFAs. Nevertheless, these fatty acids can exert a beneficial impact on the gut microbiota composition in these metabolic pathologies, and increase anti-inflammatory compounds for the microbiota fermentation, as short chain fatty acids. Linseed is a plant rich in n-3 polyunsaturated fatty acids (n- 3 PUFAs) and also in lignans and other components. We aimed to study a rebalance in n-6/n-3 PUFAs ratio in two models of rodents (rats and mice) with high fat diet (HFD)-enriched in linseed oil (LS-O) or extruded linseed (LS-E), as a matrix. We analyzed the mucosa-associated gut microbiota on colon samples in both models and demonstrated an impact of LS-E. The β-diversity was significantly different in LS-E compared to LS-O and HFD. Moreover, the α-diversity illustrated by the Shannon index tended to increase with LS-E supplementation. The abundance of the specific features Prevotella, Paraprevotella, Ruminococcus and Clostridiales were increased in LS-E compared to HFD and LS-O. LS-O did not impact the gut mucosa-associated microbiota. Extruded linseed with n-3 PUFAs, lignans and others components may increase the richness of the microbiota and restore its composition compared to an exclusive intake in n-3 PUFAs. A long-term supplementation in extruded linseed, evaluated as a matrix could be an efficient strategy in the prevention of inflammatory and metabolic diseases from its impact on gut microbiota composition

HIV-1 eradication is hindered by viral persistence in cell reservoirs, established not only in circulatory CD4+T-cells but also in tissue-resident macrophages. The nature of macrophage reservoirs and mechanisms of persistence despite combined anti-retroviral therapy (cART) remain unclear. Using genital mucosa from cART-suppressed HIV-1-infected individuals, we evaluated the implication of macrophage immunometabolic pathways in HIV-1 persistence. We demonstrate that ex vivo, macrophage tissue reservoirs contain transcriptionally active HIV-1 and viral particles accumulated in virus-containing compartments, and harbor an inflammatory IL-1R+S100A8+MMP7+M4-phenotype prone to glycolysis. Reactivation of infectious virus production and release from these reservoirs in vitro are induced by the alarmin S100A8, an endogenous factor produced by M4-macrophages and implicated in “sterile” inflammation. This process metabolically depends on glycolysis. Altogether, inflammatory M4-macrophages form a major tissue reservoir of replication-competent HIV-1, which reactivate viral production upon autocrine/paracrine S100A8-mediated glycolytic stimulation. This HIV-1 persistence pathway needs to be targeted in future HIV eradication strategies.

International audience; International guidelines are published to provide standardized information and fertility preservation (FP) care for adults and children. The purpose of the study was to conduct a modified Delphi process for generating FP guidelines for BGD. A steering committee identified 42 potential FP practices for BGD. Then 114 key stakeholders were asked to participate in a modified Delphi process via two online survey rounds and a final meeting. Consensus was reached for 28 items. Among them, stakeholders rated age-specific information concerning the risk of diminished ovarian reserve after surgery as important but rejected proposals setting various upper and lower age limits for FP.All women should be informed about the benefit/risk balance of oocyte vitrification—in particular about the likelihood of live birth according to age. FP should not be offered in rASRM stages I and II endometriosis without endometriomas. These guidelines could be useful for gynecologists to identify situations at risk of infertility and to better inform women with BGDs who might need personalizedcounseling for FP.

Smart inhalers, connected to smartphones, can provide real-life objective information about the patterns of a patient's adherence and their inhaler technique during routine use. The e-modules contain the battery and measuring sensors. Many of these are add-on modules attached externally whilst others are integrated inside the inhaler. Smart inhalers that identify a dose has either been actuated or prepared do not confirm the dose was inhaled but they can send missed dose reminders and clinical studies have highlighted their potential to improve adherence and outcomes. The e-modules that measure an inhalation profile confirm a dose has been inhaled together with providing useful information about the inhaler technique. Studies confirm that the sensors are accurate and confirm their usefulness to provide information about real-life inhaler use. Add-on e-modules are generic whereas integrated smart inhalers can be approved containing active agents and, therefore, prescribed and instructed under healthcare guidance. Real-life studies need to be carried out to demonstrate their potential to improve disease control and prevent exacerbations to justifying their increased cost.

International audience

Mucosal Associated Invariant T (MAIT) cells are evolutionary conserved innate-like T cells able to recognize bacterial and fungal ligands derived from vitamin B biosynthesis. These cells are particularly present in liver and blood but also populate mucosal sites including skin, oral, intestinal, respiratory, and urogenital tracts that are in contact with the environment and microbiota of their host. Growing evidence suggests important involvement of MAIT cells in safeguarding the mucosa against external microbial threats. Simultaneously, mucosal MAIT cells have been implicated in immune and inflammatory pathologies affecting these organs. Here, we review the specificities of mucosal MAIT cells, their functions in the protection and maintenance of mucosal barriers, and their interactions with other mucosal cells.

The vasodilator neuropeptide calcitonin gene-related peptide (CGRP) plays both detrimental and protective roles in different pathologies. CGRP is also an essential component of the neuro-immune dialogue between nociceptors and mucosal immune cells. We previously reported that CGRP strongly inhibits human immunodeficiency virus type 1 (HIV-1) infection, by suprresing Langerhans cells (LCs)-mediated HIV-1 transfer to T-cells during trans-infection. To understand the requirements for CGRP receptor (CGRP-R) activation during inhibition of HIV-1 transmission, we here investigated the anti-HIV-1 activities of full-length native CGRP and its recently developed stable analogue SAX, as well as several CGRP peptide fragments containing its binding C-terminal and activating N-terminal regions. We show that SAX significantly inhibits LCs-mediated HIV-1 trans-infection but with lower potency than CGRP, while all CGRP peptide fragments tested have no effect. In addition, CGRP readily enters the epithelial compartment of mucosal tissues and does not modify the distribution and density of mucosal immune cells. In-vivo, a single CGRP treatment in humanized mice, before vaginal challenge with high-dose HIV-1, restricts the increase in plasma viral load and maintains higher CD4+ T-cell counts. Together, our results call for the optimization and design of CGRP analogues and agonists, which could be harnessed for prevention of mucosal HIV-1 transmission.

Mucosal immune responses are crucial in protecting against pathogens entering through mucosal surfaces. However, due to difficulties in disrupting the tolerogenic environment associated with mucosa, mucosal immunity remains difficult to stimulate through vaccines and requires appropriate adjuvants. We previously demonstrated that either administered systemically to healthy macaques or locally expressed in the intestinal mucosa of acutely SIV-infected macaques, interleukin-7 (IL-7) triggers chemokine expression and immune cell homing into mucosae, suggesting its important role in the development of mucosal immune responses.We therefore examined whether local delivery of recombinant glycosylated simian IL-7 (rs-IL-7gly) to the vaginal mucosa of rhesus macaques could prepare the lower female genital tract (FGT) for subsequent immunization and act as an efficient mucosal adjuvant.First, we showed that local administration of rs-IL-7gly triggers vaginal overexpression of chemokines and infiltration of mDCs, macrophages, NKs, B- and T-cells in the chorion while MamuLa-DR+ APCs accumulated in the epithelium. Subsequent mucosal anti-DT immunization in macaques resulted in a faster, stronger, and more persistent mucosal antibody response compared to DT-immunization alone. Indeed, we detected robust productions of DT-specific IgAs and IgGs in their vaginal secretions and identified cells secreting DT-specific IgAs in their vaginal mucosa and IgGs in draining lymph nodes.Finally, the expression of chemokines involved in the organization of tertiary lymphoid structures (TLS) was only increased in the vaginal mucosa of IL-7-adjuvanted immunized macaques. Interestingly, TLSs developed around PNAd+ high endothelial venules in their lower FGT sampled 2 weeks after the last immunization.Non-traumatic vaginal administration of rs-IL-7gly prepares the mucosa to respond to subsequent local immunization and allows the development of a strong mucosal immune response in macaques, through the chemokine-dependent recruitment of immune cells, the activation of mDCs and the formation of TLSs. The localization of DT-specific IgA plasma cells in the mucosa argues for their contribution to the production of specific immunoglobulins in the vaginal secretions. Our results highlight the potential of IL-7 as a potent mucosal adjuvant to stimulate the FGT immune system and elicit vaginal antibody responses to local immunization, which is the most promising way to confer protection against many sexually transmitted diseases.

B-cell follicles constitute large reservoirs of infectious HIV/SIV associated to follicular dendritic cells and infecting follicular helper (TFH) and regulatory (TFR) T-cells in germinal centers (GCs). Thus, follicular and GC B-cells are persistently exposed to viral antigens. Despite recent development of potent HIV immunogens, numerous questions are still open regarding GC reaction during early HIV/SIV infection. Here, we dissect the dynamics of B- and T-cells in GCs of macaques acutely infected by SIV (Group SIV+) or vaccinated with Tetanus Toxoid (Group TT), a T-dependent model antigen. Systemic inflammation and mobilization of antigen-presenting cells in inguinal lymph nodes and spleen are lower in Group TT than in Group SIV+. Despite spleen GC reaction of higher magnitude in Group SIV+, the development of protective immunity could be limited by abnormal helper functions of TFH massively polarized into TFH1-like cells, by inflammation-induced recruitment of fCD8 (either regulatory or cytotoxic) and by low numbers of TFR limiting TFH/TFR competition for high affinity B-cells. Increased GC B-cells apoptosis and accumulation of CD21lo memory B-cells, unable to further participate to GC reaction, likely contribute to eliminate SIV-specific B-cells and decrease antibody affinity maturation. Surprisingly, functional GCs and potent TT-specific antibodies develop despite low levels of CXCL13.

International audience; Toxoplasma gondii, a cyst-forming apicomplexan parasite of virtually all warm-blooded species, is the etiologic agent of toxoplasmosis, a disease causing substantial public health burden worldwide. Its wide range of host species and its global occurrence probably complicate the study of its evolutionary history, and conflicting scenarios have been proposed to explain its global spread. By analysis a global set of 156 genomes and by providing the first direct estimate of T. gondii mutation rate, we show that major Old World domestic clonal lineages have spread from Europe and Africa to the Americas in the last few centuries and hybridized with New World specific clades. These events coincide with the recent expansion in the New World of the domestic cat and of a number of rodent species, the main hosts of T. gondii in the domestic environment. By combining environmental and functional data to selection inference tools, we identify the top candidate genes under selection in these hybrid populations of North and South America. We show that a unique domestic allele inherited from the recently introduced Old World lineages has been selected in these emergent domestic populations in the New World. The selection of this domestic allele is most parsimoniously explained by local adaptation to the domestic ecotype and to transmission by domestic cats.

To ensure the transport of nutrients necessary for their survival, Plasmodium falciparum parasites increase erythrocyte permeability to diverse solutes. These new permeation pathways (NPPs) have been extensively characterized in the pathogenic asexual parasite stages, however the existence of NPPs has never been investigated in gametocytes, the sexual stages responsible for transmission to mosquitoes. Here, we show that NPPs are still active in erythrocytes infected with immature gametocytes and that this activity declines along gametocyte maturation. Our results indicate that NPPs are regulated by cyclic AMP (cAMP) signaling cascade, and that the decrease in cAMP levels in mature stages results in a slowdown of NPP activity. We also show that NPPs facilitate the uptake of artemisinin derivatives and that phosphodiesterase (PDE) inhibitors can reactivate NPPs and increase drug uptake in mature gametocytes. These processes are predicted to play a key role in P. falciparum gametocyte biology and susceptibility to antimalarials., Bouyer et al. report that the new permeation pathways (NPP), responsible of modulating erythrocyte permeability to diverse solutes and considered only to be in pathogenic asexual stages of P. falciparum, are also active in erythrocytes infected with immature gametocytes and this activity declines with gametocyte maturation. NPPs are regulated by the cAMP signalling cascade, and the decrease in cAMP levels in mature stages slows NPP activity.

International audience; The development of a chronic, low-grade inflammation originating from adipose tissue in obese subjects is widely recognized to induce insulin resistance, leading to the development of type 2 diabetes. The adipose tissue microenvironment drives specific metabolic reprogramming of adipose tissue macrophages, contributing to the induction of tissue inflammation. Uncoupling protein 2 (UCP2), a mitochondrial anion carrier, is thought to separately modulate inflammatory and metabolic processes in macrophages and is up-regulated in macrophages in the context of obesity and diabetes. Here, we investigate the role of UCP2 in macrophage activation in the context of obesity-induced adipose tissue inflammation and insulin resistance. Using a myeloid-specific knockout of UCP2 (Ucp2ΔLysM), we found that UCP2 deficiency significantly increases glycolysis and oxidative respiration, both unstimulated and after inflammatory conditions. Strikingly, fatty acid loading abolished the metabolic differences between Ucp2ΔLysM macrophages and their floxed controls. Furthermore, Ucp2ΔLysM macrophages show attenuated pro-inflammatory responses toward Toll-like receptor-2 and -4 stimulation. To test the relevance of macrophage-specific Ucp2 deletion in vivo, Ucp2ΔLysM and Ucp2fl/fl mice were rendered obese and insulin resistant through high-fat feeding. Although no differences in adipose tissue inflammation or insulin resistance was found between the two genotypes, adipose tissue macrophages isolated from diet-induced obese Ucp2ΔLysM mice showed decreased TNFα secretion after ex vivo lipopolysaccharide stimulation compared with their Ucp2fl/fl littermates. Together, these results demonstrate that although UCP2 regulates both metabolism and the inflammatory response of macrophages, its activity is not crucial in shaping macrophage activation in the adipose tissue during obesity-induced insulin resistance.

The antigenic peptides processed by β cells and presented through surface HLA Class I molecules are poorly characterized. Each HLA variant, e.g. the most common HLA-A2 and HLA-A3, carries some peptide-binding specificity. Hence, features that, despite these specificities, remain shared across variants may reveal factors favoring β-cell immunogenicity. Building on our previous description of the HLA-A2/A3 peptidome of β cells, we analyzed the HLA-A3-restricted peptides targeted by circulating CD8+ T cells. Several peptides were recognized by CD8+ T cells within a narrow frequency (1-50/106), which was similar in donors with and without type 1 diabetes and harbored variable effector/memory fractions. These epitopes could be classified as conventional peptides or neo-epitopes, generated either via peptide cis-splicing or mRNA splicing, e.g. secretogranin-5 (SCG5)-009. As reported for HLA-A2-restricted peptides, several epitopes originated from β-cell granule proteins, e.g. SCG3, SCG5 and urocortin-3. Similarly, H-2Kd-restricted CD8+ T cells recognizing the murine orthologues of SCG5, urocortin-3, and proconvertase-2 infiltrated the islets of NOD mice and transferred diabetes into NOD/scid recipients. The finding of granule proteins targeted in both humans and NOD mice supports their disease relevance and identifies the insulin granule as a rich source of epitopes, possibly reflecting its impaired processing in type 1 diabetes.

Excessive glucose production by the liver is a key factor in the hyperglycemia observed in type 2 diabetes mellitus (T2DM). Here, we highlight a novel role of liver kinase B1 (Lkb1) in this regulation. We show that mice with a hepatocyte-specific deletion of Lkb1 have higher levels of hepatic amino acid catabolism, driving gluconeogenesis. This effect is observed during both fasting and the postprandial period, identifying Lkb1 as a critical suppressor of postprandial hepatic gluconeogenesis. Hepatic Lkb1 deletion is associated with major changes in whole-body metabolism, leading to a lower lean body mass and, in the longer term, sarcopenia and cachexia, as a consequence of the diversion of amino acids to liver metabolism at the expense of muscle. Using genetic, proteomic and pharmacological approaches, we identify the aminotransferases and specifically Agxt as effectors of the suppressor function of Lkb1 in amino acid-driven gluconeogenesis., Excessive glucose production by the liver contributes to poor blood glucose control in type 2 diabetes. Here the authors report that the liver kinase B1 (Lkb1) suppresses amino acid driven postprandial glucose production in the liver through the aminotransferase Agxt.

International audience; Living species including humans are continuously exposed to low levels of a myriad of endocrine active compounds that may affect their reproductive function. In contrast, experimental designs scrutinizing this question mostly consider the gestational/lactational period, select high unrealistic doses and, have rarely investigated the possible reproductive consequences in the progeny. The present study aimed at assessing comparatively a set of male reproductive endpoints according to exposure windows, gestational/lactational versus pre-pubertal to adulthood, using low doses of endocrine active substances in male rats as well as their unexposed male progeny. Animals were orally exposed to 1 mg/kg bw/d of genistein and/or vinclozolin, from conception to weaning or from prepuberty to young adulthood. A number of reproductive endpoints were assessed as well as testicular mRNA expression profiles, in the exposed rats and their unexposed progeny. Overall, the low dosage used only affected weakly most of classical reproductive endpoints. However, the gestational/lactational exposure to vinclozolin alone or combined to genistein significantly delayed the puberty onset. Contrasting with the gestational/lactational exposure, a decreased sperm production was found in the animals exposed to genistein and vinclozolin from the pre-pubertal period but also in their progeny for vinclozolin and the mixture. The expression level of several genes involved in meiosis, apoptosis and steroidogenesis was also affected differentially as a function of the exposure window in both exposed rats and unexposed offspring. We also provide further evidence that doses of endocrine active substances relevant with human exposure may affect the male reproductive phenotype and testicular transcriptome in the exposed generation as well as in the indirectly exposed offspring.

Benign adrenal tumors cover a spectrum of lesions with distinct morphology and steroid secretion. Current classification is empirical. Beyond a few driver mutations, pathophysiology is not well understood. Here, a pangenomic characterization of benign adrenocortical tumors is proposed, aiming at unbiased classification and new pathophysiological insights. Benign adrenocortical tumors (n = 146) were analyzed by transcriptome, methylome, miRNome, chromosomal alterations and mutational status, using expression arrays, methylation arrays, miRNA sequencing, SNP arrays, and exome or targeted next-generation sequencing respectively. Pathological and hormonal data were collected for all tumors. Pangenomic analysis identifies four distinct molecular categories: (1) tumors responsible for overt Cushing, gathering distinct tumor types, sharing a common cAMP/PKA pathway activation by distinct mechanisms; (2) adenomas with mild autonomous cortisol excess and non-functioning adenomas, associated with beta-catenin mutations; (3) primary macronodular hyperplasia with ARMC5 mutations, showing an ovarian expression signature; (4) aldosterone-producing adrenocortical adenomas, apart from other benign tumors. Epigenetic alterations and steroidogenesis seem associated, including CpG island hypomethylation in tumors with no or mild cortisol secretion, miRNA patterns defining specific molecular groups, and direct regulation of steroidogenic enzyme expression by methylation. Chromosomal alterations and somatic mutations are subclonal, found in less than 2/3 of cells. New pathophysiological insights, including distinct molecular signatures supporting the difference between mild autonomous cortisol excess and overt Cushing, ARMC5 implication into the adreno-gonadal differentiation faith, and the subclonal nature of driver alterations in benign tumors, will orient future research. This first genomic classification provides a large amount of data as a starting point.

Bacterial flagellin can elicit production of TLR5-mediated IL-22 and NLRC4-mediated IL-18 cytokines that act in concert to cure and prevent rotavirus (RV) infection. This study investigated the mechanism by which these cyto-kines act to impede RV. Although IL-18 and IL-22 induce each other's expression, we found that IL-18 and IL-22 both impeded RV independently of one another and did so by distinct mechanisms that involved activation of their cognate receptors in intestinal epithelial cells (IEC). IL-22 drove IEC proliferation and migration toward villus tips, which resulted in increased extrusion of highly differentiated IEC that serve as the site of RV replication. In contrast, IL-18 induced cell death of RV-infected IEC thus directly interrupting the RV replication cycle, resulting in spewing of incompetent virus into the intestinal lumen and causing a rapid drop in the number of RV-infected IEC. Together, these actions resulted in rapid and complete expulsion of RV, even in hosts with severely compromised immune systems. These results suggest that a cocktail of IL-18 and IL-22 might be a means of treating viral infections that preferentially target short-lived epithelial cells.

Efficient erythropoiesis relies on the expression of the transferrin receptor type 2 (TFR2). In erythroid precursors, TFR2 facilitates the export of the erythropoietin receptor (EPOR) to cell surface, which ensures the survival and proliferation of erythroblasts. Although TFR2 has a crucial role in erythropoiesis regulation, its mechanism of action remains to be clarified. To understand its role better, we aimed at identifying its protein partners by mass-spectrometry after immunoprecipitation in erythroid cells. Here we report the kinase MRCKα (myotonic dystrophy kinase-related CDC42-binding kinase α) as a new partner of both TFR2 and EPOR in erythroblasts. We show that MRCKα is co-expressed with TFR2, and TFR1 during terminal differentiation and regulates the internalization of the two types of transferrin receptors. The knockdown of MRCKα by shRNA in human primary erythroblasts leads to a decreased cell surface expression of both TFR1 and TFR2, an increased cell-surface expression of EPOR, and a delayed differentiation. Additionally, knockout of Mrckα in the murine MEDEP cells also leads to a striking delay in erythropoiesis, showcasing the importance of this kinase in both species. Our data highlight the importance of MRCKα in the regulation of erythropoiesis.

International audience; The ventromedial nucleus of the hypothalamus (VMN) is involved in the counterregulatory response to hypoglycemia. VMN neurons activated by hypoglycemia (glucose-inhibited [GI] neurons) have been assumed to play a critical although untested role in this response. Here, we show that expression of a dominant negative form of AMPK or inactivation of AMPK α1 and α2 subunit genes in Sf1 neurons of the VMN selectively suppressed GI neuron activity. We found that Txn2, encoding a mitochondrial redox enzyme, was strongly downregulated in the absence of AMPK activity and that reexpression of Txn2 in Sf1 neurons restored GI neuron activity. In cell lines, Txn2 was required to limit glucopenia-induced reactive oxygen species production. In physiological studies, absence of GI neuron activity after AMPK suppression in the VMN had no impact on the counterregulatory hormone response to hypoglycemia or on feeding. Thus, AMPK is required for GI neuron activity by controlling the expression of the antioxidant enzyme Txn2. However, the glucose-sensing capacity of VMN GI neurons is not required for the normal counterregulatory response to hypoglycemia. Instead, it may represent a fail-safe system in case of impaired hypoglycemia sensing by peripherally located glucose detection systems that are connected to the VMN.

Sperm malformation is a direct factor for male infertility. Multiple morphological abnormalities of the flagella (MMAF), a severe form of asthenoteratozoospermia, are characterized by immotile spermatozoa with malformed and/or absent flagella in the ejaculate. Previous studies indicated genetic heterogeneity in MMAF. To further define genetic factors underlying MMAF, we performed whole-exome sequencing in a cohort of 90 Chinese MMAF-affected men. Two cases (2.2%) were identified as carrying bi-allelic missense DNAH8 variants, variants which were either absent or rare in the control human population and were predicted to be deleterious by multiple bioinformatic tools. Re-analysis of exome data from a second cohort of 167 MMAF-affected men from France, Iran, and North Africa permitted the identification of an additional male carrying a DNAH8 homozygous frameshift variant. DNAH8 encodes a dynein axonemal heavy-chain component that is expressed preferentially in the testis. Hematoxylin-eosin staining and electron microscopy analyses of the spermatozoa from men harboring bi-allelic DNAH8 variants showed a highly aberrant morphology and ultrastructure of the sperm flagella. Immunofluorescence assays performed on the spermatozoa from men harboring bi-allelic DNAH8 variants revealed the absent or markedly reduced staining of DNAH8 and its associated protein DNAH17. Dnah8-knockout male mice also presented typical MMAF phenotypes and sterility. Interestingly, intracytoplasmic sperm injections using the spermatozoa from Dnah8-knockout male mice resulted in good pregnancy outcomes. Collectively, our experimental observations from humans and mice demonstrate that DNAH8 is essential for sperm flagellar formation and that bi-allelic deleterious DNAH8 variants lead to male infertility with MMAF.

Dendritic cells (DCs) are professional APCs, which sample Ags in the periphery and migrate to the lymph node where they activate T cells. DCs can also present native Ag to B cells through interactions observed both in vitro and in vivo. However, the mechanisms of Ag transfer and B cell activation by DCs remain incompletely understood. In this study, we report that murine DCs are an important cell transporter of Ag from the periphery to the lymph node B cell zone and also potent inducers of B cell activation both in vivo and in vitro. Importantly, we highlight a novel extracellular mechanism of B cell activation by DCs. In this study, we demonstrate that Ag released upon DC regurgitation is sufficient to efficiently induce early B cell activation, which is BCR driven and mechanistically dependent on the nuclear accumulation of the transcription factor NF-κB/cRel. Thus, our study provides new mechanistic insights into Ag delivery and B cell activation modalities by DCs and a promising approach for targeting NF-κB/cRel pathway to modulate the DC-elicited B cell responses.

International audience; Adult T-cell leukemia/lymphoma (ATL) carries a poor prognosis even in indolent subtypes. We performed targeted deep sequencing combined with mapping of HTLV-1 proviral integration sites of 61 ATL patients of African and Caribbean origin. This revealed mutations mainly affecting TCR/NF-kB (74%), T-cell trafficking (46%), immune escape (29%), and cell cycle (26%) related pathways, consistent with the genomic landscape previously reported in a large Japanese cohort. To examine the evolution of mutational signatures upon disease progression while tracking the viral integration architecture of the malignant clone, we carried out a longitudinal study of patients who either relapsed or progressed from an indolent to an aggressive subtype. Serial analysis of relapsing patients identified several patterns of clonal evolution. In progressing patients, the longitudinal study revealed NF-kB/NFAT mutations at progression that were present at a subclonal level at diagnosis (allelic frequency < 5%). Moreover, the presence in indolent subtypes of mutations affecting the TCR/NF-kB pathway, whether clonal or subclonal, was associated with significantly shorter time to progression and overall survival. Our observations reveal the clonal dynamics of ATL mutational signatures at relapse and during progression. Our study defines a new subgroup of indolent ATLs characterized by a mutational signature at high risk of transformation.

Physical oncology recognizes tissue stiffness mediated by activation of cancer-associated fibroblasts (CAF) and extracellular matrix remodeling as an active modulator of tumorigenesis, treatment resistance, and clinical outcome. Cholangiocarcinoma (CCA) is a highly aggressive and chemoresistant desmoplastic cancer enriched in CAF. CCA's stroma mechanical properties are considered responsible for its chemoresistant character. To normalize tumor mechanics, we propose a physical strategy based on remotely light-activated nanohyperthermia to modulate the tumor microenvironment. In this study, we report the use of multifunctional iron oxide nanoflowers decorated with gold nanoparticles (GIONF) as efficient nanoheaters to achieve complete tumor regression following three sessions of mild hyperthermia. The preferential uptake of GIONF by CAF allowed targeting this cell population, which resulted in a significant early reduction of tumor stiffness followed by tumor regression. In conclusion, our study highlights a spatially and temporally controlled physical strategy, GIONF-mediated photothermal therapy to deplete CAF and normalize the tumor mechanics that may apply to desmoplastic cancer and CCA treatment.

Three novel tracers designed as fluorescent surrogates of artemisinin-derived antimalarial drugs (i.e., dihydroartemisinin, artemether, arteether, and artemisone) were synthesized from dihydroartemisinin. One of these tracers, corresponding to a dihydroartemisinin/artemether/arteether mimic, showed a combination of excellent physicochemical and biological properties such as hydrolytic stability, high inhibitory potency against blood-stage parasites, similar ring-stage survival assay values than the clinical antimalarials, high cytopermeability and specific labeling of live P. falciparum cells, alkylation of heme, as well as specific covalent labeling of drug-sensitive and drug-resistant P. falciparum proteomes at physiological concentrations, consistent with a multitarget action of the drugs. Our study demonstrates that probes containing the complete structural core of clinical artemisinin derivatives can be stable in biochemical and cellular settings, and recapitulate the complex mechanisms of these frontline, yet threatened, antimalarial drugs.

Using patient-derived organoids the authors show how a specialized polarity pathway protects our gut barrier from stress-induced collapse. Findings highlight both diagnostic and therapeutic potential of the pathway for treating gut barrier dysfunction in aging, cancer, and dysbiosis., The gut barrier separates trillions of microbes from the largest immune system in the body; when compromised, a “leaky” gut barrier fuels systemic inflammation, which hastens the progression of chronic diseases. Strategies to detect and repair the leaky gut barrier remain urgent and unmet needs. Recently, a stress-polarity signaling (SPS) pathway has been described in which the metabolic sensor, AMP-kinase acts via its effector, GIV (also known as Girdin) to augment epithelial polarity exclusively under energetic stress and suppresses tumor formation. Using murine and human colon-derived organoids, and enteroid-derived monolayers (EDMs) that are exposed to stressors, we reveal that the SPS-pathway is active in the intestinal epithelium and requires a catalytically active AMP-kinase. Its pharmacologic augmentation resists stress-induced collapse of the epithelium when challenged with microbes or microbial products. In addition, the SPS-pathway is suppressed in the aging gut, and its reactivation in enteroid-derived monolayers reverses aging-associated inflammation and loss of barrier function. It is also silenced during progression of colorectal cancers. These findings reveal the importance of the SPS-pathway in the gut and highlights its therapeutic potential for treating gut barrier dysfunction in aging, cancer, and dysbiosis.

International audience; Immunological research in pigs benefits from many improvements with a direct impact on the veterinary control of pig husbandry and on biomedical models. We compiled the available knowledge to develop gating strategies to monitor simultaneously all blood immune cell types by multicolor flow cytometry in Melanoblastoma-bearing Libechov Minipigs (MeLiM). The MeLiM pig spontaneously develops cutaneous melanomas that regress few months later. We monitored lymphoid and myeloid cell subsets in 3 to 21 weeks old pigs. Interestingly, neutrophils, type III monocytes (CD163(+) CD14(+) MHC II-) and CD4(-) CD8 alpha(-) T cells are less abundant in oldest animals in contrast to eosinophils, type II monocytes (CD163(-) CD14(low) MHC II+), B cells, gamma delta T cells, CD4(+) CD8 alpha(+) and CD4(-) CD8 alpha(+) T cells. Melanoma occurrence led to changes in the blood cell composition. Higher proportions of NK cells, CD4(+) and CD4(+) CD8 alpha(+) T cells, and CD21(-) B cells among B cells are found in young melanoma-bearing piglets, consistent with the immune-mediated spontaneous regression in the MeLiM model.

Structure and function of the retina mainly rely on its fatty acid (FA) composition. Evidence from epidemiological studies and from animal experiments indicates that FA composition of the retina is influenced by the diet. Mice under chronic high-fat diet (HFD) develop metabolic syndrome, a risk factor for diabetes that is associated with structural and functional alterations of the retina. Here, we studied the impact of chronic exposure of mice to HFD on retinal FA composition. C57BL/6 J male mice were fed either a chow diet or a HFD for 11 weeks. As expected, HFD induced weight gain, adiposity, hyperglycemia and dyslipidemia. The retinal FA composition was determined by gas chromatography coupled to flame ionization detection. No significant change in the relative abundance of total saturated FAs (SFAs), total monounsaturated FAs (MUFAs) or total polyunsaturated FAs (PUFAs) was observed. However, retinas of HFD-fed mice displayed decreased amounts of C24:0 (p = 0.0231), C16:1n-7 (p < 0.0001), C18:1n-7 (p < 0.0001), C20:3n-9 (p = 0.0425) and C20:3n-6 (p = 0.0008), and an increased amount of C20:2n-6 (p < 0.0001). In addition, the ratio of linoleic acid (C18:2n-6) to alpha-linolenic acid (C18:3n-3) was increased in the retinas of HFD-fed mice (15.0 +/- 0.8 versus 11.8 +/- 0.6 in HFD and CD, respectively, p = 0.0045). No modification in the contents of arachidonic acid (C20:4n-6, AA) and docosahexaenoic acid (C22:6n-3, DHA) were observed. Analysis of dimethylacetals (DMA), which are residues of plasmalogens (Pls), revealed that the amount of Pls containing octadecanal-aldehydes (DMA C18:0) was significantly increased in HFD-fed mice (p = 0.0447). This increase was, at least in part, balanced by a decrease in Pls containing 7-octadecanal-aldehydes (DMA C18:1n-7) (p = 0.0007). In conclusion, HFD had an impact on the relative proportion of essential dietary fatty acids linoleic acid and alpha-linolenic acid that are incorporated in the retina. However, this imbalance in PUFA precursors did not alter the content of the two major retinal long-chain PUFAs, AA and DHA. HFD consumption also led to alterations in the retinal SFAs, MUFAs and Pls profiles.

Spermatozoa contain highly specialized structural features reflecting unique functions required for fertilization. Among them, the flagellum is a sperm-specific organelle required to generate the motility, which is essential to reach the egg. The flagellum integrity is, therefore, critical for normal sperm function and flagellum defects consistently lead to male infertility due to reduced or absent sperm motility defined as asthenozoospermia. Multiple morphological abnormalities of the flagella (MMAF), also called short tails, is among the most severe forms of sperm flagellum defects responsible for male infertility and is characterized by the presence in the ejaculate of spermatozoa being short, coiled, absent and of irregular caliber. Recent studies have demonstrated that MMAF is genetically heterogeneous which is consistent with the large number of proteins (over one thousand) localized in the human sperm flagella. In the past 5 years, genomic investigation of the MMAF phenotype allowed the identification of 18 genes whose mutations induce MMAF and infertility. Here we will review information about those genes including their expression pattern, the features of the encoded proteins together with their localization within the different flagellar protein complexes (axonemal or peri-axonemal) and their potential functions. We will categorize the identified MMAF genes following the protein complexes, functions or biological processes they may be associated with, based on the current knowledge in the field.

International audience; Adrenocortical tumors (ACTs) frequently cause steroid excess and present cell-cycle dysregulation. cAMP/PKA signaling is involved in steroid synthesis and play a role in cell-cycle regulation. We investigated, by cell synchronization in the different phases of the cell-cycle, the control of steroidogenesis and the contribution of PKA in adrenocortical cells (H295R and culture of primary pigmented nodular adrenocortical disease cells). Cells showed increased steroidogenesis and a maximal PKA activity at G2 phase, and a reduction at G1 phase. PRKACA overexpression, or cAMP stimulation, enhanced PKA activity and induced steroidogenesis in all synchronized groups but is not sufficient to drive cell-cycle progression. PRKAR1A inactivation enhanced PKA activity and induced STAR gene expression, only in cells in G1, and triggered cell-cycle progression in all groups.These findings provide evidence for a tight association between steroidogenesis and cell-cycle in ACTs. Moreover, PRKAR1A is essential for mediating the function of PKA activity on both steroidogenesis and cell-cycle progression in adrenocortical cells.

Human T-cell lymphotropic virus type 1 (HTLV-1) Tax oncoprotein is required for viral gene expression. Tax transactivates the viral promoter by recruiting specific transcription factors but also by interfering with general transcription factors involved in the preinitiation step, such as TFIIA and TFIID. However, data are lacking regarding Tax interplay with TFIIH, which intervenes during the last step of preinitiation. We previously reported that XPB, the TFIIH subunit responsible for promoter opening and promoter escape, is required for Tat-induced human-immunodeficiency virus promoter transactivation. Here, we investigated whether XPB may also play a role in HTLV-1 transcription. We report that Tax and XPB directly interact in vitro and that endogenous XPB produced by HTLV-1-infected T cells binds to Tax and is recruited on proviral LTRs. In contrast, XPB recruitment at the LTR is not detected in Tax-negative HTLV-1-infected T cells and is strongly reduced when Tax-induced HTLV-1 LTR transactivation is blocked. XPB overexpression does not affect basal HTLV-1 promoter activation but enhances Tax-mediated transactivation in T cells. Conversely, downregulating XPB strongly reduces Tax-mediated transactivation. Importantly, spironolactone (SP)-mediated inhibition of LTR activation can be rescued by overexpressing XPB but not XPD, another TFIIH subunit. Furthermore, an XPB mutant defective for the ATPase activity responsible for promoter opening does not show rescue of the effect of SP. Finally, XPB downregulation reduces viability of Tax-positive but not Tax-negative HTLV-1-transformed T cell lines. These findings reveal that XPB is a novel cellular cofactor hijacked by Tax to facilitate HTLV-1 transcription., IMPORTANCE HTLV-1 is considered the most potent human oncovirus and is also responsible for severe inflammatory disorders. HTLV-1 transcription is undertaken by RNA polymerase II and is controlled by the viral oncoprotein Tax. Tax transactivates the viral promoter first via the recruitment of CREB and its cofactors to the long terminal repeat (LTR). However, how Tax controls subsequent steps of the transcription process remains unclear. In this study, we explore the link between Tax and the XPB subunit of TFIIH that governs, via its ATPase activity, the promoter-opening step of transcription. We demonstrate that XPB is a novel physical and functional partner of Tax, recruited on HTLV-1 LTR, and required for viral transcription. These findings extend the mechanism of Tax transactivation to the recruitment of TFIIH and reinforce the link between XPB and transactivator-induced viral transcription.

T follicular helper (Tfh) cells play a very important role in mounting a humoral response. Studies conducted in mouse models have revealed with good kinetic and spatial resolution the dynamics of these cells in germinal centers (GC) and their cross-talk with B cells upon an immune response. However, whether a similar migratory behavior is performed by human Tfh cells is unclear, as technology to track them in situ has been lacking. In this study, we combined traditional immunohistochemistry and real-time fluorescent imaging approaches on fresh human adenoid slices to provide static and dynamic information on Tfh cells. Our data indicate that GC light zones are composed of two distinct areas in terms of Tfh cell distribution and migration. In the outer GC light zones, Tfh cells migrate actively and with a high ability to form dynamic clusters showing intense and rapid reorganization. In these outer regions, Tfh cells demonstrate multiple interactions between each other. Conversely, in central regions of GC light zones, Tfh cells are much more static, forming long-lasting conjugates. These findings reveal for the first time, to our knowledge, the dynamic behavior whereby Tfh cells migrate in human GC and highlight the heterogeneity of GC for Tfh cell motility.

Summary: The essentiality of fatty acid synthesis (FASII) products in the human pathogen Staphylococcus aureus is the underlying rationale for FASII-targeted antimicrobial drug design. Reports of anti-FASII efficacy in animals support this choice. However, restricted test conditions used previously led us to investigate this postulate in a broader, host-relevant context. We report that S. aureus rapidly adapts to FASII antibiotics without FASII mutations when exposed to host environments. FASII antibiotic administration upon signs of infection, rather than just after inoculation as commonly practiced, fails to eliminate S. aureus in a septicemia model. In vitro, serum lowers S. aureus membrane stress, leading to a greater retention of the substrates required for environmental fatty acid (eFA) utilization: eFAs and the acyl carrier protein. In this condition, eFA occupies both phospholipid positions, regardless of anti-FASII selection. Our results identify S. aureus membrane plasticity in host environments as a main limitation for using FASII antibiotics in monotherapeutic treatments. : FASII antibiotics are emerging as potential alternative therapeutics with the rise of antibiotic resistance; however, their efficacy has been controversial. Kénanian et al. find host fatty acids can compensate MRSA inhibition, thwarting the efficacy of FASII inhibitors. Bacteria can scavenge and incorporate exogenous (host) fatty acids to enable anti-FASII adaptation. Keywords: firmicute pathogens, infection, treatment failure, conditional antibiotic adaptation, antibiotic resistance, membrane phospholipids, fatty acid stress, triclosan, AFN-1252

International audience

International audience; By using the differential in level of oxidative status between normal and cancer cells, SuperOxide Dismutase (SOD) mimetics can have anti-tumor efficacy and prevent oxaliplatin-induced peripheral neuropathy. Our objective was to evaluate the neuroprotective efficacy of MAG, a new SOD mimic. In vitro, the effects of MAG alone or with oxaliplatin were studied on colon cancer cells (HT29 and CT26) and on normal fibroblast cells (NIH3T3). The cell viability (by crystal violet) as well as the production of reactive forms of oxygen and glutathione (by spectrofluorimetric assay) was measured. In vivo, efficacy on tumor growth was assessed in mice grafted with CT26 colon cancer cells. The effects on induced neurotoxicity were measured by specific behavioral Von Frey nociception, cold-plate tests, specific functional neuromuscular assay and electron microscopy. In vitro, MAG induced a production of hydrogen peroxide in all cells. At 24 h-incubation, MAG exhibits a cytotoxic activity in all cell lines. A cytotoxic additive effect of MAG and oxaliplatin was observed through oxidative burst. In vivo, oxaliplatin-treated mice associated with MAG did not counteract oxaliplatin's antitumoral efficacy. After 4 weeks of treatment with oxaliplatin combined with MAG, behavioral and functional tests showed a decrease in peripheral neuropathy induced by oxaliplatin in vivo. Electron microscopy analyses on sciatic nerves revealed an oxaliplatin-induced demyelination which is prevented by the association of MAG to this chemotherapy. In conclusion, MAG prevents the appearance of sensitive axonal neuropathy and neuromuscular disorders induced by oxaliplatin without affecting its antitumor activity.

International audience; Group B Streptococcus (GBS) is the leading cause of invasive bacterial neonatal infections. Late-onset diseases (LOD) occur between 7 and 89 days of life and are largely due to the CC17 GBS hypervirulent clone. We studied the impact of estradiol (E2) and progesterone (P4), which impregnate the fetus during pregnancy, on GBS neonatal infection in cellular and mouse models of hormonal exposure corresponding to concentrations found at birth (E2-P4 C 0) and over 7 days old (E2-P4 C 7). Using representative GBS isolates, we show that E2-P4 C 7 concentrations specifically favor CC17 GBS meningitis following mice oral infection. CC17 GBS crosses the intestinal barrier through M cells. This process mediated by the CC17-specific surface protein Srr2 is enhanced by E2-P4 C 7 concentrations which promote M cell differentiation and CC17 GBS invasiveness. Our findings provide an explanation for CC17 GBS responsibility in LOD in link with neonatal gastrointestinal tract maturation and hormonal imprint.

Novel approaches for adjunctive therapy are urgently needed for complicated infections and patients with compromised immunity. Necrotizing fasciitis (NF) is a destructive skin and soft tissue infection. Despite treatment with systemic antibiotics and radical debridement of necrotic tissue, lethality remains high. The key iron regulatory hormone hepcidin was originally identified as a cationic antimicrobial peptide (AMP), but its putative expression and role in the skin, a major site of AMP production, have never been investigated. We report here that hepcidin production is induced in the skin of patients with group A Streptococcus (GAS) NF. In a GAS-induced NF model, mice lacking hepcidin in keratinocytes failed to restrict systemic spread of infection from an initial tissue focus. Unexpectedly, this effect was due to its ability to promote production of the CXCL1 chemokine by keratinocytes, resulting in neutrophil recruitment. Unlike CXCL1, hepcidin is resistant to degradation by major GAS proteases and could therefore serve as a reservoir to maintain steady-state levels of CXCL1 in infected tissue. Finally, injection of synthetic hepcidin at the site of infection can limit or completely prevent systemic spread of GAS infection, suggesting that hepcidin agonists could have a therapeutic role in NF.

Background The primary objective was to evaluate the rates of older patients with colorectal cancer (CRC) who were eligible for a clinical trial, invited to participate, and, ultimately, included. The secondary objective was to assess the reasons for ineligibility, noninvitation, and noninclusion and factors associated. Materials and Methods The Sujets AGés dans les Essais Cliniques (SAGE; Older Subjects in Clinical Trials) multicenter prospective cohort was established in seven centers (10 departments of medical oncology, digestive oncology, and digestive surgery) between 2012 and 2016. All patients with CRC aged 65 or older were studied. The endpoints were clinical trial availability, patient's eligibility, invitation, and enrollment in a trial. Results We included 577 older patients (mean age ± SD: 75.6 ± 7 years; males: 56%; metastasis: 41%). Thirty-seven trials were ongoing (one trial for older patients). Of the 474 patients with at least one available trial for their cancer stage and site, 127 (27%) were eligible; 84 of these 127 (66%) were invited to participate, and 70 of these 84 (83%) were included. In a multivariate analysis, noninvitation was found to be associated with older age (p = .016): adjusted relative risk (95% confidence interval), 0.14 (0.02–0.60) for ≥80 vs. 65–69; 0.54 (0.18-1.04) for 75–79 vs. 65–69; 0.47 (0.17-0.93) for 70–74 vs. 65–69. Conclusion Three-quarters of older patients with CRC were ineligible for a clinical trial. One-third of the eligible patients were not invited to participate in a trial, and 17% of invited patients were not included. Few trials are reserved for older patients. Patients aged 80 or older were significantly less likely to be eligible for a trial and invited to participate. Clinical trial identification number: NCT01754636. Implications for Practice The results of this study suggest that barriers to participation of older patients in clinical trials are particularly marked at age 80 years or older. Secondly, the results emphasize the need for trials for older patients. Thirdly, there is also a need for more pragmatic “real-world” trials, rather than solely randomized trials performed in idealized settings with strictly selected patients. Large prospective observational cohorts with a precise follow-up of toxicity, functional decline, and quality of life may constitute one way of generating more data on the risk-benefit ratio for cancer treatments in older patients.

Triple-negative breast cancer (TNBC) represents 10% of all breast cancers and is a very heterogeneous disease. Globally, women with TNBC have a poor prognosis, and the development of effective targeted therapies remains a real challenge. Patient-derived xenografts (PDX) are clinically relevant models that have emerged as important tools for the analysis of drug activity and predictive biomarker discovery. The purpose of this work was to analyze the molecular heterogeneity of a large panel of TNBC PDX (n = 61) in order to test targeted therapies and identify biomarkers of response. At the gene expression level, TNBC PDX represent all of the various TNBC subtypes identified by the Lehmann classification except for immunomodulatory subtype, which is underrepresented in PDX. NGS and copy number data showed a similar diversity of significantly mutated gene and somatic copy number alteration in PDX and the Cancer Genome Atlas TNBC patients. The genes most commonly altered were TP53 and oncogenes and tumor suppressors of the PI3K/AKT/mTOR and MAPK pathways. PDX showed similar morphology and immunohistochemistry markers to those of the original tumors. Efficacy experiments with PI3K and MAPK inhibitor monotherapy or combination therapy showed an antitumor activity in PDX carrying genomic mutations of PIK3CA and NRAS genes. TNBC PDX reproduce the molecular heterogeneity of TNBC patients. This large collection of PDX is a clinically relevant platform for drug testing, biomarker discovery and translational research.

International audience; No abstract available

International audience; Sorafenib is the standard of care for the treatment of advanced hepatocellular carcinoma (HCC). However, identifying secreted biomarkers that predict sorafenib efficacy in all HCC patients remains challenging. It was recently reported that sorafenib interferes with protein homeostasis and inhibits global translation in tumour cells. A likely consequence of this inhibition would be the interruption of autocrine loops. The aim of the present study was to investigate the effect of sorafenib on two growth factors implicated in autocrine loops and HCC tumour invasion: amphiregulin (AREG) and vascular endothelial growth factor (VEGF). ELISA, quantitative polymerase chain reaction analysis, western blotting and a cytokine array were performed on HCC cell lines and the prognostic role of these two biomarkers in HCC patients was evaluated. Serum AREG and VEGF levels were assayed by ELISA in 55 patients with advanced HCC treated with sorafenib. It was observed that sorafenib decreased AREG, VEGF and cytokine expression at the transcriptional and post-transcriptional levels. All HCC patients in our cohort had detectable concentrations of AREG and VEGF both at baseline and after sorafenib treatment. The decreased serum levels of AREG and VEGF after 15 days of sorafenib treatment were significantly associated with better overall and progression-free survival. The results of the multivariate analysis demonstrated that a decrease in AREG was an independent prognostic indicator of overall survival (hazard ratio, 0.208; 95% confidence interval, 0.173-0.673; P=0.0003). These results suggest that sorafenib inhibits autocrine loops and that early decrease in serum AREG or VEGF levels predicts sorafenib efficacy in HCC patients.

International audience; Key Points • The RNA regulators PUMILIO sustain HSPC and acute myeloid leukemia cell growth by upregulating FOXP1 expression through direct binding to 2 FOXP1-39UTR PUMILIO-binding elements. • FOXP1 mediates PUMILIO growth-promoting activities by repressing expression of p21 CIP1 and p27 KIP1 cell cycle inhibitors. RNA-binding proteins (RBPs) have emerged as important regulators of invertebrate adult stem cells, but their activities remain poorly appreciated in mammals. Using a short hairpin RNA strategy, we demonstrate here that the 2 mammalian RBPs, PUMILIO (PUM)1 and PUM2, members of the PUF family of posttranscriptional regulators, are essential for hematopoietic stem/progenitor cell (HSPC) proliferation and survival in vitro and in vivo upon reconstitution assays. Moreover, we found that PUM1/2 sustain myeloid leukemic cell growth. Through a proteomic approach, we identified the FOXP1 transcription factor as a new target of PUM1/2. Contrary to its canonical repressive activity, PUM1/2 rather promote FOXP1 expression by a direct binding to 2 canonical PUM responsive elements present in the FOXP1-39 untranslated region (UTR). Expression of FOXP1 strongly correlates with PUM1 and PUM2 levels in primary HSPCs and myeloid leukemia cells. We demonstrate that FOXP1 by itself supports HSPC and leukemic cell growth, thus mimicking PUM activities. Mechanis-tically, FOXP1 represses the expression of the p21 2CIP1 and p27 2KIP1 cell cycle inhibitors. Enforced FOXP1 expression reverses shPUM antiproliferative and proapoptotic activities. Altogether, our results reveal a novel regulatory pathway, underscoring a previously unknown and interconnected key role of PUM1/2 and FOXP1 in regulating normal HSPC and leukemic cell growth.