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Background Elevated BNP and the N-terminal fragment of the proBNP (NT-proBNP) are hallmarks of heart failure (HF). Generally, both biomarkers parallel each other. In patients receiving sacubitril/valsartan, BNP remained stable while NT-proBNP decreased. As BNP and NT-proBNP assays have limited specificity due to cross-reactivity, we quantified by mass spectrometry (MS) the contributing molecular species. Methods We included 356 healthy volunteers, 100 patients with acute dyspnoea (49 acute decompensated HF; 51 dyspnoea of non-cardiac origin), and 73 patients with chronic HF and reduced ejection fraction treated with sacubitril/valsartan. BNP and NT-proBNP immunoreactivities (BNPir and NT-proBNPir) were measured by immunoassays (Abbott ARCHITECT and Roche Diagnostics proBNPII) and proBNP-derived peptides and glycosylation at serine 44 by MS on plasma samples. Results BNPir corresponded to the sum of proBNP1–108, BNP1–32, BNP3–32, and BNP5–32 (R2 = 0.9995), while NT-proBNPir corresponded to proBNP1–108 and NT-proBNP1–76 not glycosylated at serine 44 (R2 = 0.992). NT-proBNPir was better correlated (R2 = 0.9597) than BNPir (R2 = 0.7643) with proBNP signal peptide (a surrogate of proBNP production). In patients receiving sacubitril/valsartan, non-glycosylated NT-proBNP1–76 remained constant (P = 0.84) despite an increase in NT-proBNP1–76 and its glycosylation (P < 0.0001). ProBNP1–108 remained constant (P = 0.12) while its glycosylation increased (P < 0.0001), resulting in a decrease in non-glycosylated proBNP1–108 (P < 0.0001), and in NT-proBNPir. Conclusions Glycosylation interfered with NT-proBNPir measurement, explaining the discrepant evolution of these 2 biomarkers in patients receiving sacubitril/valsartan. Both BNPir and NT-proBNPir are surrogates of proBNP1–108 production, NT-proBNPir being more robust in the clinical contexts studied.

The cellular prion protein PrPC partners with caveolin-1 (CAV1) in neurodegenerative diseases but whether this interplay occurs in cancer has never been investigated. By leveraging patient and cell line datasets, we uncover a molecular link between PrPC and CAV1 across cancer. Using cell-based assays, we show that PrPC regulates the expression of and interacts with CAV1. PrPC additionally controls the expression of the amyloid precursor protein APP and of the Aβ generating enzyme BACE1, and regulates the levels of Aβ, whose accumulation is a central event in Alzheimer’s disease. We further identify DKK1 and DKK3, involved in both Alzheimer’s disease and cancer progression, as targets of the PrPC-dependent axis. Finally, we establish that antibody-mediated blocking of the Aβ-PrPC interaction delays the growth of prostate cancer cell line-derived xenografts and prevents the development of metastases. Our data additionally support an enrichment of the Aβ-PrPC-dependent pathway in the basal subtype of prostate cancer, associated with anti-hormonal therapy resistance, and in mesenchymal colon cancer, associated with poor prognosis. Thus, based on a parallel with neurodegenerative diseases, our results bring to light an Aβ-PrPC axis and support the potential of targeting this pathway in patients with selected subtypes of prostate and colon cancer.

Selective serotonin reuptake inhibitors (SSRI) are common first-line treatments for major depression. However, a significant number of depressed patients do not respond adequately to these pharmacological treatments. In the present preclinical study, we demonstrate that organic cation transporter 2 (OCT2), an atypical monoamine transporter, contributes to the effects of SSRI by regulating the routing of the essential amino acid tryptophan to the brain. Contrarily to wild-type mice, OCT2-invalidated mice failed to respond to prolonged fluoxetine treatment in a chronic depression model induced by corticosterone exposure recapitulating core symptoms of depression,i.e., anhedonia, social withdrawal, anxiety, and memory impairment. After corticosterone and fluoxetine treatment, the levels of tryptophan and its metabolites serotonin and kynurenine were decreased in the brain ofOCT2mutant mice compared to wild-type mice and reciprocally tryptophan and kynurenine levels were increased in mutants’ plasma. OCT2 was detected by immunofluorescence in several structures at the blood-cerebrospinal fluid (CSF) or brain-CSF interface. Tryptophan supplementation during fluoxetine treatment increased brain concentrations of tryptophan in wild-type and OCT2 mutant mice, yet more efficiently in WT than in mutants, while discretely increasing 5-HT concentrations. Importantly, tryptophan supplementation improved the sensitivity to fluoxetine treatment ofOCT2mutant mice, impacting chiefly anhedonia and short-term memory. Western blot analysis showed that glycogen synthase kinase-3β (GSK3β) and mammalian/mechanistic target of rapamycin (mTOR) intracellular signaling was impaired inOCT2mutant mice brain after corticosterone and fluoxetine treatment and, conversely, tryptophan supplementation recruited selectively the mTOR protein complex 2. This study provides the first evidence of the physiological relevance of OCT2-mediated tryptophan transport, and its biological consequences on serotonin homeostasis in the brain and SSRI efficacy.

Oxytocin (OT) is a prominent regulator of many aspects of mammalian social behavior and stored in large dense-cored vesicles (LDCVs) in hypothalamic neurons. It is released in response to activity-dependent Ca 2+ influx, but is also dependent on Ca 2+ release from intracellular stores, which primes LDCVs for exocytosis. Despite its importance, critical aspects of the Ca 2+ -dependent mechanisms of its secretion remain to be identified. Here we show that lysosomes surround dendritic LDCVs, and that the direct activation of endolysosomal two-pore channels (TPCs) provides the critical Ca 2+ signals to prime OT release by increasing the releasable LDCV pool without directly stimulating exocytosis. We observed a dramatic reduction in plasma OT levels in TPC knockout mice, and impaired secretion of OT from the hypothalamus demonstrating the importance of priming of neuropeptide vesicles for activity-dependent release. Furthermore, we show that activation of type 1 metabotropic glutamate receptors sustains somatodendritic OT release by recruiting TPCs. The priming effect could be mimicked by a direct application of nicotinic acid adenine dinucleotide phosphate, the endogenous messenger regulating TPCs, or a selective TPC2 agonist, TPC2-A1-N, or blocked by the antagonist Ned-19. Mice lacking TPCs exhibit impaired maternal and social behavior, which is restored by direct OT administration. This study demonstrates an unexpected role for lysosomes and TPCs in controlling neuropeptide secretion, and in regulating social behavior.

International audience; No abstract available

ObjectivesAlthough critical in animal and human development and pathology, a measurement of the quantitative expression of 5-HTR serotonin receptors on animal or human valvular tissues has never been performed.MethodsQuantification of the most frequent 5-HTRs reported as being present in human peripheral tissue was performed using radiolabeled agonists/antagonists. A membrane protein extract from normal human valves (aortic/mitral/tricuspid and some pulmonary) and associated diseased left myocardium, all unusable in clinics, were obtained from the Homograft bank.ResultsWe analyzed 5-HT1AR/5-HT1B/DR/5-HT2AR/5-HT2BR/5-HT 2CR/5-HT4R/5-HT7R from 28 hearts. We confirmed the presence of tissue and measured the quantitative content for respective proteins in femtomol/mg of protein extracts: for 5-HT2AR (35.9+/−0.7), 5-HT2BR (28.8+/−1.3) but also a newly observed and robust expression for 5-HT4R (38+/−4.2). We identified one, 5-HT1ARs (4.9+/−0.3), and the possible expression, but at a very low level, of previously reported 5-HT1B/DRs (1.3+/−0.5) as well as the new 5-HT7Rs (3.5+/0.1) and 5-HT2CRs (1.2+/−0.1). Interestingly, by using univariate analysis, we were able to observe many correlations between the different 5-HTR levels of expression especially between 5-HT1AR/5-HT1B/DR and also between 5-HT4R/5-HT7R, but none were observed between 5-HT2AR and 5-HT2BR. Using multivariate analyses for a specific 5-HTR level of expression, after adjustment for implantation sites and other 5-HTRs, we found that 5-HT1AR was correlated with 5-HT1B/DR;5-HT4R with 5-HT7R and 5-HT1AR;5-HT2BR with 5-HT2AR only. For 5-HT2C, no correlation was observed.Conclusion5-HT2AR/5-HT2BR and 5-HT4R were all observed to have a high and equal level of expression on human valves, but that of 5-HT1AR was more limited. Since these non-5-HT2Rs are coupled with different G-proteins, with specific signaling, theoretically they may control the main 5-HT2R signaling (i.e., PLC/DAG-PKC-ERK/Ras/Src signaling) involved in valvular fibrosis and degeneration.

Monoamine oxidases (MAO; MAO-A and MAO-B in mammals) are enzymes catalyzing the degradation of biogenic amines, including monoamine neurotransmitters. In humans, coding mutations in MAOs are extremely rare and deleterious. Here, we assessed the structural and biochemical consequences of a point mutation (P106L) in the singlemaogene of the blind cavefishAstyanax mexicanus. This mutation decreased mao enzymatic activity by ~3-fold, probably as a result of decreased flexibility in one of the three loops forming the entrance of the active site, thus reducing the access of substrates. HPLC measurements in brains of mutant and non-mutant larvae and adults of the cave and surface morphs of the species showed major disturbances in serotonin, dopamine and noradrenalin (and metabolites) contents in mutants, demonstrating that the P106Lmaomutation is fully responsible for monoaminergic disequilibrium in the P106Lmaomutant cavefish brain. The outcomes of the mutation were different in the posterior brain (containing the raphe nucleus) and the anterior brain (containing fish-specific hypothalamic serotonergic clusters), revealing contrasting properties in neurotransmitter homeostasis in these different neuronal groups. We also discovered that the effects of the mutation were partially compensated by a decrease in activity of the tph, the serotonin biosynthesis rate-limiting enzyme. Finally, the neurochemical outcomes of themaoP106L mutation differed in many respects from a treatment with deprenyl, an irreversible MAO inhibitor, showing that genetic and pharmacological interference with MAO function are not the same. Our results shade light on our understanding of cavefish evolution, on the specificities of fish monoaminergic systems, and on MAO-dependent homeostasis of brain neurochemistry in general.

International audience; Aims Our objectives were to validate a murine model of chronic cardiotoxicity induced by Doxorubicin (Dox) and Trastuzumab (Trast) and to test the potential cardio-protective effect of metoprolol. Methods and results Male C57Bl6 mice were intraperitoneally injected during 2 weeks with Dox (24 mg/kg) or saline, and then with Trast (10 mg/kg) or saline for two more weeks. Half of the mice received metoprolol (100 mg/kg). Cardiotoxicity was defined by a decline in left ventricular ejection fraction (LVEF) ≥ 10 points. At Day 42, Dox + Trast-treated mice exhibited a 13-points decline in LVEF (74 ± 2.6% vs. 87 ± 0.8% for control mice, P < 0.001) and a severe cardiac atrophy (heart weight: 105 ± 2.7 mg vs. 119 ± 3.9 mg for control mice, P < 0.01). This cardiac atrophy resulted from an excess of cardiac necrosis (assessed by plasma cardiac troponin I level: 3.2 ± 0.4 ng/L vs. 1.3 ± 0.06 ng/L for control mice, P < 0.01), an increase in apoptosis (caspase 3 activity showing a six-fold increase for Dox + Trast-treated mice vs. controls, P < 0.001), and cardiomyocyte atrophy (myocyte size: 0.67 ± 0.08 μm 2 vs. 1.36 ± 0.10 μm 2 for control mice, P < 0.001). In addition, Dox + Trast-treated mice were shown to have an increased cardiac oxidative stress (164 ± 14 dihydroethidine-marked nuclei per area vs. 56 ± 9.5 for control mice, P < 0.01) and increased cardiac fibrosis (the semi-quantitative fibrosis score was threefold higher for Dox + Trast-treated mice as compared with controls, P < 0.01). Metoprolol was not able to prevent either the decrease in LVEF or the severe cardiac atrophy, the cardiac necrosis, and the cardiac remodelling induced by chemotherapies. Conclusion A murine model of chronic cardiotoxicity induced by Dox and Trast was characterized by a decrease in cardiac function, a cardiac apoptosis and necrosis leading to cardiomyocyte atrophy. Metoprolol did not prevent this cardiotoxicity.

Background: Sacubitril/valsartan (S/V) treatment is beneficial in patients with heart failure with reduced ejection fraction (HFrEF), but its mode of action remains elusive, although it involves the increase in ANP (atrial natriuretic peptide). Methods: Combining mass spectrometry and enzymatic assay in the plasma of 73 HFrEF patients treated with S/V and controls, we deciphered proANP processing that converts proANP into 4 vasoactive peptides. Results: We found that proANP processing is sequential and involved meprin B, ECE (endothelin-converting enzyme) 1, and ANPEP (aminopeptidase N). This processing is limited in HFrEF patients via the downregulation of proANP production, corin, and meprin B activities by miR-425 and miR1-3p. S/V restored or compensated proANP processing by downregulating miR-425 and miR1-3p, hence increasing levels of proANP-derived bioactive peptides. In contrast, S/V directly and indirectly partially inhibited ECE1 and ANPEP. ECE1 partial inhibition resulted in a lower-than-expected increase in ET1 (endothelin 1), tilting the vasoactive balance toward vasodilation, and possibly hypotension. Furthermore, proANP glycosylation interferes with the midregional proANP assay –a clinical surrogate for proANP production, preventing any pathophysiological interpretation of the results. The analysis of S/V dose escalation with respect to baseline treatments suggests S/V-specific effects. Conclusions: These findings offer mechanistic evidence to the natriuretic peptide -defective state in HFrEF, which is improved by S/V. These data also strongly suggests that S/V increases plasma ANP by multiple mechanisms that involve 2 microRNAs, besides its protection from NEP (neprilysin) cleavage. Altogether, these data provide new insights on HFrEF pathophysiology and the mode of action of S/V.

ENC, J-MC, SP, and AZ have patents on the use of CD38inhibitors ENC, J-MC, SP, and AZ have patents on the use of CD38inhibitors ENC, J-MC, SP, and AZ have patents on the use of CD38inhibitors; International audience; Duchenne muscular dystrophy (DMD) is characterized by progressive muscle degeneration. Two important deleterious features are a Ca2+ dysregulation linked to Ca2+ influxes associated with ryanodine receptor hyperactivation, and a muscular nicotinamide adenine dinucleotide (NAD+ ) deficit. Here, we identified that deletion in mdx mice of CD38, a NAD+ glycohydrolase-producing modulators of Ca2+ signaling, led to a fully restored heart function and structure, with skeletal muscle performance improvements, associated with a reduction in inflammation and senescence markers. Muscle NAD+ levels were also fully restored, while the levels of the two main products of CD38, nicotinamide and ADP-ribose, were reduced, in heart, diaphragm, and limb. In cardiomyocytes from mdx/CD38-/- mice, the pathological spontaneous Ca2+ activity was reduced, as well as in myotubes from DMD patients treated with isatuximab (SARCLISA® ) a monoclonal anti-CD38 antibody. Finally, treatment of mdx and utrophin-dystrophin-deficient (mdx/utr-/- ) mice with CD38 inhibitors resulted in improved skeletal muscle performances. Thus, we demonstrate that CD38 actively contributes to DMD physiopathology. We propose that a selective anti-CD38 therapeutic intervention could be highly relevant to develop for DMD patients.

International audience; Purpose: Early and reliable prognostication after cardiac arrest (CA) remains crucial. We hypothesized that protein-S100B (PS100B) could predict more accurately outcome in the early phase of CA compared with other current biomarkers.Methods: This prospective single-center study included 330 adult comatose non-traumatic successfully resuscitated CA patients, treated with targeted temperature management but not extra-corporeal life support. Lactate, pH, creatinine, NSE, and PS100B were sampled in ICU early after return of spontaneous circulation (ROSC) corresponding to admission (Adm). Serial measurements were also performed at H24 and H48. PS100B was the sole biomarker blinded to physicians.Measurements and main results: The median delay between ROSC and first PS100B sampling was 220 min. At admission, all biomarkers were significantly associated with good outcome (CPC1-2; 109 patients) at 3-month follow-up (P ≤ 0.001, except for NSE: P = 0.03). PS100B-Adm showed the best AUC of ROC curves for outcome prediction at 3-month (AUC 0.83 [95%-CI: 0.78-0.88]), compared with other biomarkers (P < 0.0001), while AUC for lactate-Adm was higher than for NSE-Adm. AUC for PS100B-H24 was significantly higher than for other biomarkers except NSE-H24 (P ≤ 0.0001), while AUC for NSE-H24 was higher than for lactate-H24 and pH-H24. AUCs for PS100-H48 and NSE-H48 were significantly higher than for all other biomarkers (P < 0.001). Compared to patients with decreased PS100B values over time, an increasing PS100B value between admission and H24 was significantly associated with poor outcome at 3 months (P = 0.001). No-flow, initial non-shockable rhythm, PS100B-Adm, lactate-Adm, pH-Adm, clinical seizures, and absence of therapeutic hypothermia were independent predictors associated with poor outcome at 3-month in multivariate analysis. Net-Reclassification-Index was 70%, 64%, and 81% when PS100B-Adm was added to the clinical model, to clinical model with NSE-Adm, and to clinical model with standard biological parameters, respectively.Conclusions: Early PS100B compared with other biomarkers was independently correlated with outcome after CA, with an interesting added value.

Background The roles of thrombophilia and cardiovascular risk factors in sudden sensorineural hearing loss (SSNHL) remain controversial. Cochlear microthrombosis and vasospasm have been hypothesized as possible pathogenic mechanisms of SSNHL. This article investigates the circulating serotonin and homocysteine levels besides thrombophilia screening in patients with idiopathic SSNHL. Methods A total of 133 SSNHL patients and age- and sex-matched controls were investigated (discovery cohort). Measurement included common inherited natural coagulation inhibitors, factor VIII, von Willebrand factor (VWF), antiphospholipid antibodies, homocysteine, and serotonin (whole blood, platelet, and plasma) levels, along with frequent relevant genetic variants. A validation cohort (128 SSNHL patients) was studied for homocysteine and serotonin levels. Results and Conclusion In the discovery cohort, 58.6% of patients exhibited thrombophilia, of which most had a low to moderate titers of antiphospholipid antibodies and high levels of factor VIII/VWF. Twenty-seven patients (20%) had mild-to-moderate hyperhomocysteinemia or were homozygous for the methylenetetrahydrofolate reductase (MTHFR) C677T mutation. Regarding serotonin, SSNHL patients had elevated whole blood levels that remained within the normal range and normal platelet content. However, approximately 90% patients of both cohorts had elevated plasma serotonin. Elevated plasma serotoninemia was accompanied by serotonylation of platelet rhoA protein. This study shows that increased plasma serotonin appears as a biomarker of SSNHL (specificity: ∼96%, sensitivity: ∼90%) and could participate in the pathophysiology of SSNHL.

Background Dialysis patients are at increased risk of HF. However, diagnostic utility of NT-proBNP as a biomarker is decreased in patients on dialysis. GDF-15 and cNEP are biomarkers of distinct mechanisms that may contribute to HF pathophysiology in such cohorts. The aim of this study was to determine whether growth differentiation factor-15 (GDF-15) and circulating neprilysin (cNEP) improve the diagnosis of congestive heart failure (HF) in patients on dialysis. Methods and results We compared circulating concentrations of NT-proBNP, GDF-15, and cNEP along with cNEP activity in patients on chronic dialysis without (n = 80) and with HF (n = 73), as diagnosed by clinical parameters and post-dialysis echocardiography. We used correlation, linear and logistic regression as well as receiver operating characteristic (ROC) analyses. Compared to controls, patients with HF had higher median values of NT-proBNP (16,216 [interquartile range, IQR = 27739] vs. 2883 [5866] pg/mL, p p = 0.014), but not cNEP (315 [107] vs. 318 [124] pg/mL, p = 0.818). Median cNEP activity was significantly lower in HF vs. controls (0.189 [0.223] vs. 0.257 [0.166] nmol/mL/min, p p Conclusion We present novel comparative data on physiologically distinct circulating biomarkers for HF in patients on dialysis. cNEP activity but not concentration and GDF-15 provided incremental diagnostic information over clinical covariates and NT-proBNP and may aid in diagnosing HF in dialysis patients. Graphic abstract

Background and Purpose: Ischemic stroke is one of the most common causes of morbidity and mortality and has numerous clinical mimics. Previous studies have suggested a potential role of the tryptophan-serotonin (5-HT)-kynurenine (TSK) axis in ischemic stroke. Studies assessing this axis in the hyperacute phase of ischemic stroke (, Graphical Abstract

Objectives The association between outcome and kidney injury detected at discharge from the ICU using different biomarkers remains unknown. The objective was to evaluate the association between 1-year survival and kidney injury at ICU discharge. Design Ancillary investigation of a prospective observational study. Setting Twenty-one ICUs with 1-year follow-up. Patients Critically ill patients receiving mechanical ventilation and/or hemodynamic support for at least 24 hours were included. Interventions Serum creatinine, plasma Cystatin C, plasma neutrophil gelatinase-associated lipocalin, urinary neutrophil gelatinase-associated lipocalin, plasma Proenkephalin A 119-159, and estimated glomerular filtration rate (on serum creatinine and plasma Cystatin C) were measured at ICU discharge among ICU survivors. Measurements and main results The association between kidney biomarkers at discharge and mortality was estimated using logistic model with and without adjustment for prognostic factors previously identified in this cohort. Subgroup analyses were performed in patients with discharge serum creatinine less than 1.5-fold baseline at ICU discharge. Among 1,207 ICU survivors included, 231 died during the year following ICU discharge (19.2%). Estimated glomerular filtration rate was significantly lower and kidney injury biomarkers higher at discharge in nonsurvivors. The association between biomarker levels or estimated glomerular filtration rate and mortality remained after adjustment to potential cofounding factors influencing outcome. In patients with low serum creatinine at ICU discharge, 25-47% of patients were classified as subclinical kidney injury depending on the biomarker. The association between kidney biomarkers and mortality remained and mortality was higher than patients without subclinical kidney injury. The majority of patients who developed acute kidney injury during ICU stay had elevated biomarkers of kidney injury at discharge even with apparent recovery based on serum creatinine (i.e., subclinical acute kidney disease). Conclusions Elevated kidney biomarkers measured at ICU discharge are associated with poor 1-year outcome, including in patients with low serum creatinine at ICU discharge.

The cellular prion protein PrP

Iron is essential to key biological processes of all living organisms. Proper iron levels must be maintained to meet biological needs and prevent toxicity. Given the central role played by the hormone hepcidin in systemic iron homeostasis, extensive research has sought to identify regulators of its expression. Diverse evidence shows the gut to be an essential sensor and regulator of iron homeostasis, independently of other known hepcidin regulators, including bone marrow signals. Here we identify gut-derived serotonin as a key physiological factor in hepcidin regulation. In response to hypoxia, serotonin synthesized and secreted by enterochromaffin cells can act beyond the gut to repress hepcidin expression in the liver, through a 5-HT2Breceptor-dependent pathway. Bone marrow transplant experiments clearly indicate the gut is responsible for hepcidin repression. This regulatory system appears to be conserved in humans: a significant negative correlation exists between hepcidin and serotonin levels in the serum of healthy individuals. Our findings imply hepcidin regulation by serotonin is a physiological process, and modulation of the gut serotonergic system may have broad therapeutic implications.

Background Autism spectrum disorders (ASD) are associated with dysregulation of the microbiota-gut-brain axis, changes in microbiota composition as well as in the fecal, serum, and urine levels of microbial metabolites. Yet a causal relationship between dysregulation of the microbiota-gut-brain axis and ASD remains to be demonstrated. Here, we hypothesized that the microbial metabolite p-Cresol, which is more abundant in ASD patients compared to neurotypical individuals, could induce ASD-like behavior in mice. Results Mice exposed to p-Cresol for 4 weeks in drinking water presented social behavior deficits, stereotypies, and perseverative behaviors, but no changes in anxiety, locomotion, or cognition. Abnormal social behavior induced by p-Cresol was associated with decreased activity of central dopamine neurons involved in the social reward circuit. Further, p-Cresol induced changes in microbiota composition and social behavior deficits could be transferred from p-Cresol-treated mice to control mice by fecal microbiota transplantation (FMT). We also showed that mice transplanted with the microbiota of p-Cresol-treated mice exhibited increased fecal p-Cresol excretion, compared to mice transplanted with the microbiota of control mice. In addition, we identified possible p-Cresol bacterial producers. Lastly, the microbiota of control mice rescued social interactions, dopamine neurons excitability, and fecal p-Cresol levels when transplanted to p-Cresol-treated mice. Conclusions The microbial metabolite p-Cresol induces selectively ASD core behavioral symptoms in mice. Social behavior deficits induced by p-Cresol are dependant on changes in microbiota composition. Our study paves the way for therapeutic interventions targeting the microbiota and p-Cresol production to treat patients with ASD.

The role of mast cells has been questioned in sickle cell disease (SCD). We performed a prospective study evaluating plasma histamine and tryptase levels in a cohort of paediatric and adult patients, in steady state (n = 132) and during vaso-occlusive crisis (VOC) (n = 121). Histamine level was elevated in 18% of patients in steady state and in 61% during VOC. Median histamine level was significantly higher during VOC than in steady state (24·1 [7·0-45·0] vs 9·6 [6·2-14·4] nmol/l, P

International audience; Autism spectrum disorder (ASD) is characterized by early onset of behavioral and cognitive alterations. Low plasma levels of oxytocin (OT) have also been found in ASD patients; recently, a critical role for the enzyme CD38 in the regulation of OT release was demonstrated. CD38 is important in regulating several Ca 2+-dependent pathways, but beyond its role in regulating OT secretion, it is not known whether a deficit in CD38 expression leads to functional modifications of the prefrontal cortex (PFC), a structure involved in social behavior. Here, we report that CD38 2/2 male mice show an abnormal cortex development, an excitation-inhibition balance shifted toward a higher excitation, and impaired synaptic plasticity in the PFC such as those observed in various mouse models of ASD. We also show that a lack of CD38 alters social behavior and emotional responses. Finally, examining neu-romodulators known to control behavioral flexibility, we found elevated monoamine levels in the PFC of CD38 2/2 adult mice. Overall, our study unveiled major changes in PFC physiologic mechanisms and provides new evidence that the CD38 2/2 mouse could be a relevant model to study pathophysiological brain mechanisms of mental disorders such as ASD.-Martucci, L. A multiscale analysis in CD38-/-mice unveils major prefrontal cortex dysfunctions. FASEB J. 33, 000-000 (2019). www.fasebj.org KEY WORDS: behavior • oxytocin • autism • monoamines • excitation Autism spectrum disorder (ASD) covers a group of neu-rodevelopmental disorders characterized by behavior-al and cognitive disturbances with early-onset deficits in language acquisition and social interaction. ASD is highly inherited but the genetic determinants are poorly understood. The genetic basis of ASD has been associated with copy-number variations or single-nucleotide poly-morphism (SNP) in genes involved in brain development, synapse formation, or cell signaling (1). ASD is frequently associated with excessive cortical growth (2), and a current hypothesis is that the behavioral defects observed in ASD are due to impairments in synaptic functioning and plasticity (1, 3-5). For example, some mutations affect gluta-matergic synaptic transmission such as for the SH3 and multiple ankyrin repeat domain (SHANK) proteins (4-6) or the neuroligins (3, 7). One important consequence of these mutations is that the mechanisms of synaptic plasticity are altered and affect ionotropic NMDA receptors or metabotropic glutamate receptors regulating learning processes and cognitive functions (8, 9). Recently, the hypothesis of an increase in the excitation-inhibition (E-I) ratio in neuronal circuits emerged as a common patho-physiological principle that could explain the genesis of cognitive and social behavior deficits in ASD (10).

Aim This study aimed at evaluating the effects of sacubitril/valsartan on neprilysin (NEP), and the metabolism of natriuretic peptides in heart failure (HF) and providing additional mechanistic information on the mode of action of the drug. Methods and results We enrolled 73 chronic HF patients who were switched from angiotensin-converting enzyme inhibitor or angiotensin receptor blocker to sacubitril/valsartan. In addition to clinical and echocardiographic assessment, plasma biomarkers were measured at baseline, day 30 and day 90 after initiation of treatment. Sacubitril/valsartan led to decrease in New York Heart Association class and improvement of echocardiographic parameters, as well as a dose-dependent decrease in soluble NEP (sNEP) activity, while sNEP concentration remained unchanged. Neprilysin inhibition translated into an increase in its substrates such as atrial natriuretic peptide (ANP), substance P, and glucagon-like peptide 1, the latter translating into a decrease in fructosamine. Cardiac troponin and soluble ST2 levels, biomarkers of HF severity unrelated to NEP metabolism also decreased. While there was a ∼4-fold increase in ANP, we observed no change in plasma brain natriuretic peptide (BNP) and plasma BNP activity, and a mild decrease in N-terminal proBNP (NT-proBNP) concentrations. Finally, we found a progressive increase in the relationship between BNP and NT-proBNP, which strongly correlated with an increase in T71 proBNP glycosylation (R2 = 0.94). Conclusion Sacubitril/valsartan rapidly and strongly reduced sNEP activity, leading to an increase in levels of NEP substrates. These data suggest a pleiotropic favourable impact of sacubitril/valsartan on the metabolism of HF patients with ANP rather than BNP as major effectors amongst natriuretic peptides.

Amyloid-based neurodegenerative diseases such as prion, Alzheimer's, and Parkinson's diseases have distinct etiologies and clinical manifestations, but they share common pathological events. These diseases are caused by abnormally folded proteins (pathogenic prions PrPSc in prion diseases, β-amyloids/Aβ and Tau in Alzheimer's disease, α-synuclein in Parkinson's disease) that display β-sheet-enriched structures, propagate and accumulate in the nervous central system, and trigger neuronal death. In prion diseases, PrPSc-induced corruption of the physiological functions exerted by normal cellular prion proteins (PrPC) present at the cell surface of neurons is at the root of neuronal death. For a decade, PrPC emerges as a common cell surface receptor for other amyloids such as Aβ and α-synuclein, which relays, at least in part, their toxicity. In lipid-rafts of the plasma membrane, PrPC exerts a signaling function and controls a set of effectors involved in neuronal homeostasis, among which are the RhoA-associated coiled-coil containing kinases (ROCKs). Here we review (i) how PrPC controls ROCKs, (ii) how PrPC-ROCK coupling contributes to neuronal homeostasis, and (iii) how the deregulation of the PrPC-ROCK connection in amyloid-based neurodegenerative diseases triggers a loss of neuronal polarity, affects neurotransmitter-associated functions, contributes to the endoplasmic reticulum stress cascade, renders diseased neurons highly sensitive to neuroinflammation, and amplifies the production of neurotoxic amyloids.

The serotonergic 2B receptor (5-HT2BR), expressed in the central nervous system and at the periphery, contributes to the regulation of several physiological processes such as cardio-vascular, pulmonary, bone and neuronal functions. Due to its multifaceted roles, signaling pathways and cell targets controlled by the 5-HT2BR are still the subject of intensive research. Here, we review how exploiting the dynamics of differentiation of the 1C11 neuronal stem cell line allows to identify several 5-HT2BR-coupled signaling pathways and targets, among which the serotonin transporter, involved in the homeostasis of serotonergic neurons and their adaptive response to selective serotonin-reuptake inhibitors (SSRIs) like fluoxetine (Prozac®). In addition, mesoblastic stem cell lines permit to show that along the osteogenic differentiation, the 5-HT2BR controls the activity of the tissue-non-specific alkaline phosphatase, a major enzyme for bone formation. Finally, the 5-HT2BR expressed by pulpal stem cells takes part to natural tooth repair upon 5-HT release by injury-activated platelets.

Background: Ischemic cardiovascular diseases, particularly acute myocardial infarction (MI), is one of the leading causes of mortality worldwide. Indoleamine 2, 3-dioxygenase 1 (IDO) catalyzes 1 rate-limiting step of L-tryptophan metabolism, and emerges as an important regulator of many pathological conditions. We hypothesized that IDO could play a key role to locally regulate cardiac homeostasis after MI. Methods: Cardiac repair was analyzed in mice harboring specific endothelial or smooth muscle cells or cardiomyocyte or myeloid cell deficiency of IDO and challenged with acute myocardial infarction. Results: We show that kynurenine generation through IDO is markedly induced after MI in mice. Total genetic deletion or pharmacological inhibition of IDO limits cardiac injury and cardiac dysfunction after MI. Distinct loss of function of IDO in smooth muscle cells, inflammatory cells, or cardiomyocytes does not affect cardiac function and remodeling in infarcted mice. In sharp contrast, mice harboring endothelial cell–specific deletion of IDO show an improvement of cardiac function as well as cardiomyocyte contractility and reduction in adverse ventricular remodeling. In vivo kynurenine supplementation in IDO-deficient mice abrogates the protective effects of IDO deletion. Kynurenine precipitates cardiomyocyte apoptosis through reactive oxygen species production in an aryl hydrocarbon receptor–dependent mechanism. Conclusions: These data suggest that IDO could constitute a new therapeutic target during acute MI.

International audience; Background: Takayasu arteritis (TAK) is a large vessel vasculitis resulting in artery wall remodeling with segmental stenosis and/or aneurysm formation. Mast cells (MCs) are instrumental in bridging cell injury and inflammatory response.Objectives: This study sought to investigate the contribution of MCs on vessel permeability, angiogenesis, and fibrosis in patients with TAK. Methods: MC activation and their tissue expression were assessed in sera and in aorta from patients with TAK and from healthy donors (HDs). In vivo permeability was assessed using a modified Miles assay. Subconfluent cultured human umbilic vein endothelial cells and fibroblasts were used in vitro to investigate the effects of MC mediators on angiogenesis and fibrogenesis.Results: This study found increased levels of MC activation markers (histamine and indoleamine 2,3-dioxygenase) in sera of patients with TAK compared with in sera of HDs. Marked expression of MCs was shown in aortic lesions of patients with TAK compared with in those of noninflammatory aorta controls. Using Miles assay, this study showed that sera of patients with TAK significantly increased vascular permeability in vivo as compared with that of HDs. Vessel permeability was abrogated in MC-deficient mice. MCs stimulated by sera of patients with TAK supported neoangiogenesis (increased human umbilic vein endothelial cell proliferation and branches) and fibrosis by inducing increased production of fibronectin, type 1 collagen, and a-smooth muscle actin by fibroblasts as compared to MCs stimulated by sera of HD.Conclusions: MCs are a key regulator of vascular lesions in patients with TAK and may represent a new therapeutic target in large vessel vasculitis.

The poly(ADP-ribose) polymerase (PARP) inhibitor PJ34 has been reported to improve endothelial dysfunction in the peripheral system. We addressed the role of PJ34 on the vascular tone and vasoreactivity during development in the mouse brain. Blood flows were measured in the basilar trunk using ultrasonography. Cerebral vasoreactivity or vasodilation reserve was estimated as a percentage increase in mean blood flow velocities (mBFV) recorded under normoxia-hypercapnia in control and after PJ34 administration. Non-selective and selective eNOS and nNOS inhibitors were used to evaluate the role of NO-pathway into the hemodynamic effects of PJ34. PJ34 increased mBFVs from 15.8 &plusmn, 1.6 to 19.1 &plusmn, 1.9 cm/s (p = 0.0043) in neonatal, from 14.6 &plusmn, 1.4 to 16.1 &plusmn, 0.9 cm/s (p = 0.0049) in adult, and from 15.7 &plusmn, 1.7 to 17.5 &plusmn, 2.0 cm/s (p = 0.0024) in aged mice 48 h after administration. These PJ34 values were similar to those measured in age-matched control mice under normoxia-hypercapnia. This recruitment was mediated through the activation of constitutive NO synthases in both the neonatal (38.2 &plusmn, 6.7 nmol/min/mg protein) and adult (31.5 &plusmn, 4.4 nmol/min/mg protein) brain, as compared to age-matched control brain (6.9 &plusmn, 0.4 and 6.3 &plusmn, 0.7 nmol/min/mg protein), respectively. In addition, quite selective eNOS inhibitor was able to inhibit the recruitment. PJ34 by itself is able to increase cerebral blood flow through the NO-pathway activation at least over 48 h after a single administration.

© 2020 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology. This is an open access article under the terms of the Creative Commons Attribution-Non Commercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes., Aims: Changes in echocardiographic parameters and biomarkers of cardiac and venous pressures or estimated plasma volume during hospitalization associated with decongestive treatments in acute heart failure (AHF) patients with either preserved left ventricular ejection fraction (LVEF) (HFPEF) or reduced LVEF (HFREF) are poorly assessed. Methods and results: From the metabolic road to diastolic heart failure: diastolic heart failure (MEDIA‐DHF) study, 111 patients were included in this substudy: 77 AHF (43 HFPEF and 34 HFREF) and 34 non‐cardiac dyspnea patients. Echocardiographic measurements and blood samples were obtained within 4 h of presentation at the emergency department and before hospital discharge. In AHF patients, echocardiographic indices of cardiac and venous pressures, including inferior vena cava diameter [from 22 (16–24) mm to 13 (11–18) mm, P = 0.009], its respiratory variability [from 32 (8–44) % to 43 (29–70) %, P = 0.04], medial E/e' [from 21.1 (15.8–29.6) to 16.6 (11.7–24.3), P = 0.004], and E wave deceleration time [from 129 (105–156) ms to 166 (128–203) ms, P = 0.003], improved during hospitalization, similarly in HFPEF and HFREF patients. By contrast, no changes were seen in non‐cardiac dyspnea patients. In AHF patients, all plasma biomarkers of cardiac and venous pressures, namely B‐type natriuretic peptide [from 935 (514–2037) pg/mL to 308 (183–609) pg/mL, P < 0.001], mid‐regional pro‐atrial natriuretic peptide [from 449 (274–653) pmol/L to 366 (242–549) pmol/L, P < 0.001], and soluble CD‐146 levels [from 528 (406–654) ng/mL to 450 (374–529) ng/mL, P = 0.003], significantly decreased during hospitalization, similarly in HFPEF and HFREF patients. Echocardiographic parameters of cardiac chamber dimensions [left ventricular end‐diastolic volume: from 120 (76–140) mL to 118 (95–176) mL, P = 0.23] and cardiac index [from 2.1 (1.6–2.6) mL/min/m2 to 1.9 (1.4–2.4) mL/min/m2, P = 0.55] were unchanged in AHF patients, except tricuspid annular plane systolic excursion (TAPSE) that improved during hospitalization [from 16 (15–19) mm to 19 (17–21) mm, P = 0.04]. Estimated plasma volume increased in both AHF [from 4.8 (4.2–5.6) to 5.1 (4.4–5.8), P = 0.03] and non‐cardiac dyspnea patients (P = 0.01). Serum creatinine [from 1.18 (0.90–1.53) to 1.19 (0.86–1.70) mg/dL, P = 0.89] and creatinine‐based estimated glomerular filtration rate [from 59 (40–75) mL/min/1.73m2 to 56 (38–73) mL/min/1.73m2, P = 0.09] were similar, while plasma cystatin C [from 1.50 (1.20–2.27) mg/L to 1.78 (1.33–2.59) mg/L, P < 0.001] and neutrophil gelatinase associated lipocalin (NGAL) [from 127 (95–260) ng/mL to 167 (104–263) ng/mL, P = 0.004] increased during hospitalization in AHF. Conclusions: Echocardiographic parameters and plasma biomarkers of cardiac and venous pressures improved during AHF hospitalization in both acute HFPEF and HFREF patients, while cardiac chamber dimensions, cardiac output, and estimated plasma volume showed minimal changes., This study was supported by a grant from the European Union funded by the Seventh Framework Programme for Health in 2010 (FP7-HEALTH-2010-MEDIA; Luxembourg) (F.Z., P.R., A. M) and research fellowship from Japan Heart Foundation (E. A.). P.R., N.G., T.C., and F.Z. are supported by a public grant overseen by the French National Research Agency (ANR) as part of the second “Investissements d’Avenir” programmes Fighting Heart Failure (reference: ANR-15-RHU-0004), GEENAGE Impact Lorraine Université d’Excellence and by the Contrat de Plan Etat Lorraine IT2MP and FEDER Lorraine. LNLVA is supported by a training grant from the European Society of Cardiology (2015) and a travelling award from the International Society for Heart and Lung Transplantation (August 2015 and 2016). LNLVA gratefully acknowledges the financial support from the Fund for Cardiac Surgery through the Jacqueline Bernheim prize 2015.