PLoS Biol

Inflammation of the central nervous system (CNS) induces endothelial blood-brain barrier (BBB) opening as well as the formation of a tight junction barrier between reactive astrocytes at the Glia Limitans. We hypothesized that the CNS parenchyma may acquire protection from the reactive astrocytic Glia Limitans not only during neuroinflammation but also when BBB integrity is compromised in the resting state. Previous studies found that astrocyte-derived Sonic hedgehog (SHH) stabilizes the BBB during CNS inflammatory disease, while endothelial-derived desert hedgehog (DHH) is expressed at the BBB under resting conditions. Here, we investigated the effects of endothelial Dhh on the integrity of the BBB and Glia Limitans. We first characterized DHH expression within endothelial cells at the BBB, then demonstrated that DHH is down-regulated during experimental autoimmune encephalomyelitis (EAE). Using a mouse model in which endothelial Dhh is inducibly deleted, we found that endothelial Dhh both opens the BBB via the modulation of forkhead box O1 (FoxO1) transcriptional activity and induces a tight junctional barrier at the Glia Limitans. We confirmed the relevance of this glial barrier system in human multiple sclerosis active lesions. These results provide evidence for the novel concept of "chronic neuroinflammatory tolerance" in which BBB opening in the resting state is sufficient to stimulate a protective barrier at the Glia Limitans that limits the severity of subsequent neuroinflammatory disease. In summary, genetic disruption of the BBB generates endothelial signals that drive the formation under resting conditions of a secondary barrier at the Glia Limitans with protective effects against subsequent CNS inflammation. The concept of a reciprocally regulated CNS double barrier system has implications for treatment strategies in both the acute and chronic phases of multiple sclerosis pathophysiology

S-2-hydroxyglutarate regulates CD8+ T-lymphocyte fate.

R-2-hydroxyglutarate accumulates to millimolar levels in cancer cells with gain-of-function isocitrate dehydrogenase 1/2 mutations. These levels of R-2-hydroxyglutarate affect 2-oxoglutarate-dependent dioxygenases. Both metabolite enantiomers, R- and S-2-hydroxyglutarate, are detectible in healthy individuals, yet their physiological function remains elusive. Here we show that 2-hydroxyglutarate accumulates in mouse CD8+ T cells in response to T-cell receptor triggering, and accumulates to millimolar levels in physiological oxygen conditions through a hypoxia-inducible factor 1-alpha (HIF-1α)-dependent mechanism. S-2-hydroxyglutarate predominates over R-2-hydroxyglutarate in activated T cells, and we demonstrate alterations in markers of CD8+ T-cell differentiation in response to this metabolite. Modulation of histone and DNA demethylation, as well as HIF-1α stability, mediate these effects. S-2-hydroxyglutarate treatment greatly enhances the in vivo proliferation, persistence and anti-tumour capacity of adoptively transferred CD8+ T cells. Thus, S-2-hydroxyglutarate acts as an immunometabolite that links environmental context, through a metabolic-epigenetic axis, to immune fate and function

Rôle de la dysfonction endothéliale dans la physiopathologie de l’insuffisance cardiaque à fraction d’éjection préservée

Heart Failure with Preserved Ejection Fraction (HFpEF) is a chronic disease associated with high mortality which affects predominantly elderly (>65 years) hypertensive women with cardiovascular and non-cardiovascular comorbidities. Unfortunately, molecular mechanisms underlying this disease are poorly understood. A new, but yet untested paradigm, has recently emerged focusing on the crucial role of the vascular bed in the etiology of HFpEF. The E3 ubiquitin ligase, PDZRN3, a mediator of the non-canonical Wnt pathway, was reported to enhance vascular permeability. Our objective is the investigation of the long-term consequences of endothelial PDZRN3 signaling activation on induced-HFpEF pathology.We have generated triple transgenic mutant mice with post-natal restrictive and inducible endothelial expression of Pdzrn3 (iEC-Pdzrn3 mice), as an exploratory in vivo tool. From 3 months, iEC-Pdzrn3 mice displayed hemodynamic parameters of HFpEF with a significant strong elevation of the end-diastolic pressure compared with their littermates. At 8 months iEC-Pdzn3 mice did not exhibit a cardiac inflammatory phenotype or fibrosis progression. However, along with diastolic dysfunction, serious vascular leakage evidenced by albumin, fibrinogen, and immunoglobulin G vascular extravasation together with cardiac edema were observed. Western diet exacerbated inflammatory and fibrotic heart phenotype in both iEC-Pdzrn3 and littermates mice without worsening diastolic dysfunction. Finally, heart exploration of the murine HFpEF model based on the obesity-diabetic comorbidities (Lprdb/db mice) revealed vascular permeability comparable to iEC-Pdzrn3 mice.Our findings highlight a causal relationship between vascular dysfunction and HFpEF pathology.L’insuffisance cardiaque à fraction d’éjection préservée (ICFEp) est une maladie chronique associée à une mortalité élevée. Les patients sont majoritairement des femmes âgées (>65 ans) hypertendues avec une prévalence élevée de comorbidités cardiovasculaires telles que l’obésité, le diabète de type 2, l’hypertension artérielle ou encore la fibrillation atriale. Le diagnostic de l’ICFEp est difficile à établir en raison d’un manque de critères spécifiques et il n’existe pas à ce jour de réel traitement ciblé permettant d’améliorer la qualité de vie, de réduire la mortalité ou la durée d’hospitalisation de ces patients. Malheureusement, les mécanismes moléculaires sous-jacents de cette maladie sont encore mal compris mais un nouveau paradigme a été proposé ces dernières années. Il suggère un rôle central de la dysfonction des cellules endothéliales cardiaques dans l’apparition de l’ICFEp. L'ubiquitine ligase E3 RING PDZRN3, est un médiateur de la voie Wnt non-canonique qui régule la morphogénèse vasculaire ainsi que l’intégrité des cellules endothéliales. Nos travaux ont eu pour objectif d’étudier les conséquences de l'activation de la signalisation endothéliale PDZRN3 sur la fonction cardiaque.Nous avons généré des souris transgéniques avec une surexpression spécifique de PDZRN3 dans les cellules endothéliales et inductible en post-natal (souris iEC-Pdzrn3). A partir de 3 mois, les souris iEC-Pdzrn3 présentent des paramètres hémodynamiques d’ICFEp avec une élévation significative de la pression diastolique par rapport à leurs contrôles. À 8 mois, les souris iEC-Pdzn3 ne présentent pas un phénotype cardiaque dit inflammatoire ni de signes de progression de fibrose. Cependant, en plus de signes de dysfonction diastolique, une perméabilité vasculaire accrue mise en évidence par une extravasation vasculaire d'albumine, de fibrinogène et d'immunoglobuline G associée à un œdème cardiaque ont été observés. De plus, la mise sous régime Western a exacerbé le phénotype inflammatoire et fibrotique des souris iEC-Pdzrn3 mais aussi de leurs contrôles sans aggraver le dysfonctionnement diastolique. Enfin, l'exploration cardiaque d’un modèle murin d’ICFEp basé sur les comorbidités obésité et diabète (souris Lprdb/db) a révélé une perméabilité vasculaire comparable à celle observée chez les souris iEC-Pdzrn3.Ces résultats mettent donc en évidence une relation de cause à effet entre le dysfonctionnement vasculaire et la physiopathologie de l’ICFEp

Role of endothelial dysfunction in the pathophysiology of heart failure with preserved ejection fraction

L’insuffisance cardiaque à fraction d’éjection préservée (ICFEp) est une maladie chronique associée à une mortalité élevée. Les patients sont majoritairement des femmes âgées (>65 ans) hypertendues avec une prévalence élevée de comorbidités cardiovasculaires telles que l’obésité, le diabète de type 2, l’hypertension artérielle ou encore la fibrillation atriale. Le diagnostic de l’ICFEp est difficile à établir en raison d’un manque de critères spécifiques et il n’existe pas à ce jour de réel traitement ciblé permettant d’améliorer la qualité de vie, de réduire la mortalité ou la durée d’hospitalisation de ces patients. Malheureusement, les mécanismes moléculaires sous-jacents de cette maladie sont encore mal compris mais un nouveau paradigme a été proposé ces dernières années. Il suggère un rôle central de la dysfonction des cellules endothéliales cardiaques dans l’apparition de l’ICFEp. L'ubiquitine ligase E3 RING PDZRN3, est un médiateur de la voie Wnt non-canonique qui régule la morphogénèse vasculaire ainsi que l’intégrité des cellules endothéliales. Nos travaux ont eu pour objectif d’étudier les conséquences de l'activation de la signalisation endothéliale PDZRN3 sur la fonction cardiaque.Nous avons généré des souris transgéniques avec une surexpression spécifique de PDZRN3 dans les cellules endothéliales et inductible en post-natal (souris iEC-Pdzrn3). A partir de 3 mois, les souris iEC-Pdzrn3 présentent des paramètres hémodynamiques d’ICFEp avec une élévation significative de la pression diastolique par rapport à leurs contrôles. À 8 mois, les souris iEC-Pdzn3 ne présentent pas un phénotype cardiaque dit inflammatoire ni de signes de progression de fibrose. Cependant, en plus de signes de dysfonction diastolique, une perméabilité vasculaire accrue mise en évidence par une extravasation vasculaire d'albumine, de fibrinogène et d'immunoglobuline G associée à un œdème cardiaque ont été observés. De plus, la mise sous régime Western a exacerbé le phénotype inflammatoire et fibrotique des souris iEC-Pdzrn3 mais aussi de leurs contrôles sans aggraver le dysfonctionnement diastolique. Enfin, l'exploration cardiaque d’un modèle murin d’ICFEp basé sur les comorbidités obésité et diabète (souris Lprdb/db) a révélé une perméabilité vasculaire comparable à celle observée chez les souris iEC-Pdzrn3.Ces résultats mettent donc en évidence une relation de cause à effet entre le dysfonctionnement vasculaire et la physiopathologie de l’ICFEp.Heart Failure with Preserved Ejection Fraction (HFpEF) is a chronic disease associated with high mortality which affects predominantly elderly (>65 years) hypertensive women with cardiovascular and non-cardiovascular comorbidities. Unfortunately, molecular mechanisms underlying this disease are poorly understood. A new, but yet untested paradigm, has recently emerged focusing on the crucial role of the vascular bed in the etiology of HFpEF. The E3 ubiquitin ligase, PDZRN3, a mediator of the non-canonical Wnt pathway, was reported to enhance vascular permeability. Our objective is the investigation of the long-term consequences of endothelial PDZRN3 signaling activation on induced-HFpEF pathology.We have generated triple transgenic mutant mice with post-natal restrictive and inducible endothelial expression of Pdzrn3 (iEC-Pdzrn3 mice), as an exploratory in vivo tool. From 3 months, iEC-Pdzrn3 mice displayed hemodynamic parameters of HFpEF with a significant strong elevation of the end-diastolic pressure compared with their littermates. At 8 months iEC-Pdzn3 mice did not exhibit a cardiac inflammatory phenotype or fibrosis progression. However, along with diastolic dysfunction, serious vascular leakage evidenced by albumin, fibrinogen, and immunoglobulin G vascular extravasation together with cardiac edema were observed. Western diet exacerbated inflammatory and fibrotic heart phenotype in both iEC-Pdzrn3 and littermates mice without worsening diastolic dysfunction. Finally, heart exploration of the murine HFpEF model based on the obesity-diabetic comorbidities (Lprdb/db mice) revealed vascular permeability comparable to iEC-Pdzrn3 mice.Our findings highlight a causal relationship between vascular dysfunction and HFpEF pathology

Role of endothelial dysfunction in the pathophysiology of heart failure with preserved ejection fraction

L’insuffisance cardiaque à fraction d’éjection préservée (ICFEp) est une maladie chronique associée à une mortalité élevée. Les patients sont majoritairement des femmes âgées (>65 ans) hypertendues avec une prévalence élevée de comorbidités cardiovasculaires telles que l’obésité, le diabète de type 2, l’hypertension artérielle ou encore la fibrillation atriale. Le diagnostic de l’ICFEp est difficile à établir en raison d’un manque de critères spécifiques et il n’existe pas à ce jour de réel traitement ciblé permettant d’améliorer la qualité de vie, de réduire la mortalité ou la durée d’hospitalisation de ces patients. Malheureusement, les mécanismes moléculaires sous-jacents de cette maladie sont encore mal compris mais un nouveau paradigme a été proposé ces dernières années. Il suggère un rôle central de la dysfonction des cellules endothéliales cardiaques dans l’apparition de l’ICFEp. L'ubiquitine ligase E3 RING PDZRN3, est un médiateur de la voie Wnt non-canonique qui régule la morphogénèse vasculaire ainsi que l’intégrité des cellules endothéliales. Nos travaux ont eu pour objectif d’étudier les conséquences de l'activation de la signalisation endothéliale PDZRN3 sur la fonction cardiaque.Nous avons généré des souris transgéniques avec une surexpression spécifique de PDZRN3 dans les cellules endothéliales et inductible en post-natal (souris iEC-Pdzrn3). A partir de 3 mois, les souris iEC-Pdzrn3 présentent des paramètres hémodynamiques d’ICFEp avec une élévation significative de la pression diastolique par rapport à leurs contrôles. À 8 mois, les souris iEC-Pdzn3 ne présentent pas un phénotype cardiaque dit inflammatoire ni de signes de progression de fibrose. Cependant, en plus de signes de dysfonction diastolique, une perméabilité vasculaire accrue mise en évidence par une extravasation vasculaire d'albumine, de fibrinogène et d'immunoglobuline G associée à un œdème cardiaque ont été observés. De plus, la mise sous régime Western a exacerbé le phénotype inflammatoire et fibrotique des souris iEC-Pdzrn3 mais aussi de leurs contrôles sans aggraver le dysfonctionnement diastolique. Enfin, l'exploration cardiaque d’un modèle murin d’ICFEp basé sur les comorbidités obésité et diabète (souris Lprdb/db) a révélé une perméabilité vasculaire comparable à celle observée chez les souris iEC-Pdzrn3.Ces résultats mettent donc en évidence une relation de cause à effet entre le dysfonctionnement vasculaire et la physiopathologie de l’ICFEp.Heart Failure with Preserved Ejection Fraction (HFpEF) is a chronic disease associated with high mortality which affects predominantly elderly (>65 years) hypertensive women with cardiovascular and non-cardiovascular comorbidities. Unfortunately, molecular mechanisms underlying this disease are poorly understood. A new, but yet untested paradigm, has recently emerged focusing on the crucial role of the vascular bed in the etiology of HFpEF. The E3 ubiquitin ligase, PDZRN3, a mediator of the non-canonical Wnt pathway, was reported to enhance vascular permeability. Our objective is the investigation of the long-term consequences of endothelial PDZRN3 signaling activation on induced-HFpEF pathology.We have generated triple transgenic mutant mice with post-natal restrictive and inducible endothelial expression of Pdzrn3 (iEC-Pdzrn3 mice), as an exploratory in vivo tool. From 3 months, iEC-Pdzrn3 mice displayed hemodynamic parameters of HFpEF with a significant strong elevation of the end-diastolic pressure compared with their littermates. At 8 months iEC-Pdzn3 mice did not exhibit a cardiac inflammatory phenotype or fibrosis progression. However, along with diastolic dysfunction, serious vascular leakage evidenced by albumin, fibrinogen, and immunoglobulin G vascular extravasation together with cardiac edema were observed. Western diet exacerbated inflammatory and fibrotic heart phenotype in both iEC-Pdzrn3 and littermates mice without worsening diastolic dysfunction. Finally, heart exploration of the murine HFpEF model based on the obesity-diabetic comorbidities (Lprdb/db mice) revealed vascular permeability comparable to iEC-Pdzrn3 mice.Our findings highlight a causal relationship between vascular dysfunction and HFpEF pathology

J Cereb Blood Flow Metab

Blood brain barrier (BBB) disruption is a critical component of the pathophysiology of cognitive impairment of vascular etiology (VCI) and associated with Alzheimer's disease (AD). The Wnt pathway plays a crucial role in BBB maintenance, but there is limited data on its role in cognitive pathologies. The E3 ubiquitin ligase PDZRN3 is a regulator of the Wnt pathway. In a murine model of VCI, overexpressing in endothelial cell (EC) exacerbated BBB hyperpermeability and accelerated cognitive decline. We extended these observations, in both VCI and AD models, showing that EC-specific depletion of reinforced the BBB, with a decrease in vascular permeability and a subsequent spare in cognitive decline. We found that in cerebral vessels, Pdzrn3 depletion protects against AD-induced Wnt target gene alterations and enhances endothelial tight junctional proteins. Our results provide evidence that Wnt signaling could be a molecular link regulating BBB integrity and cognitive decline under VCI and AD pathologies

Arterioscler Thromb Vasc Biol

Genome-wide association studies have revealed robust associations of common genetic polymorphisms in an intron of the PHACTR-1 (phosphatase and actin regulator 1) gene (chr6p24), with cervical artery dissection, spontaneous coronary artery dissection, and fibromuscular dysplasia. The aim was to assess its role in the pathogenesis of cervical artery dissection or fibromuscular dysplasia. Using various tissue-specific Cre-driver mouse lines, was deleted either in endothelial cells using 2 tissue-specific Cre-driver (PDGFB [platelet-derived growth factor B]-Cre mice and Tie2 [tyrosine kinase with immunoglobulin and EGF homology domains]-Cre) and smooth muscle cells (smooth muscle actin-Cre) with a third tissue-specific Cre-driver. To test the efficacy of the deletion after cre-induction, we confirmed first, a decrease in Phactr1 transcription and Phactr1 expression in endothelial cell and smooth muscle cell isolated from Phactr1 and Phactr1 mice. Irrespective to the tissue or the duration of the deletion, mice did not spontaneously display pathological phenotype or vascular impairment: mouse survival, growth, blood pressure, large vessel morphology, or actin organization were not different in knockout mice than their comparatives littermates. Challenging vascular function and repair either by angiotensin II-induced hypertension or limb ischemia did not lead to vascular morphology or function impairment in Phactr1-deleted mice. Similarly, there were no more consequences of deletion during embryogenesis in endothelial cells. Loss of PHACTR-1 function in the cells involved in vascular physiology does not appear to induce a pathological vascular phenotype. The in vivo effect of the intronic variation described in genome-wide association studies is unlikely to involve downregulation in PHACTR-1 expression

Arterioscler Thromb Vasc Biol

While endothelial dysfunction is suggested to contribute to heart failure with preserved ejection fraction pathophysiology, understanding the importance of the endothelium alone, in the pathogenesis of diastolic abnormalities has not yet been fully elucidated. Here, we investigated the consequences of specific endothelial dysfunction on cardiac function, independently of any comorbidity or risk factor (diabetes or obesity) and their potential effect on cardiomyocyte. The ubiquitine ligase , expressed in endothelial cells (ECs), was shown to destabilize tight junction. A genetic mouse model in which is overexpressed in EC (iEC-Pdzrn3) in adults was developed. EC-specific expression increased cardiac leakage of IgG and fibrinogen blood-born molecules. The induced edema demonstrated features of diastolic dysfunction, with increased end-diastolic pressure, alteration of dP/dt min, increased natriuretic peptides, in addition to limited exercise capacity, without major signs of cardiac fibrosis and inflammation. Electron microscopic images showed edema with disrupted EC-cardiomyocyte interactions. RNA sequencing analysis of gene expression in cardiac EC demonstrated a decrease in genes coding for endothelial extracellular matrix proteins, which could be related to the fragile blood vessel phenotype. Irregularly shaped capillaries with hemorrhages were found in heart sections of iEC- mice. We also found that a high-fat diet was not sufficient to provoke diastolic dysfunction; high-fat diet aggravated cardiac inflammation, associated with an altered cardiac metabolic signature in EC- mice, reminiscent of heart failure with preserved ejection fraction features. An increase of endothelial permeability is responsible for mediating diastolic dysfunction pathophysiology and for aggravating detrimental effects of a high-fat diet on cardiac inflammation and metabolism

Decrease of Pdzrn3 is required for heart maturation and protects against heart failure

International audienceAbstract Heart failure is the final common stage of most cardiopathies. Cardiomyocytes (CM) connect with others via their extremities by intercalated disk protein complexes. This planar and directional organization of myocytes is crucial for mechanical coupling and anisotropic conduction of the electric signal in the heart. One of the hallmarks of heart failure is alterations in the contact sites between CM. Yet no factor on its own is known to coordinate CM polarized organization. We have previously shown that PDZRN3, an ubiquitine ligase E3 expressed in various tissues including the heart, mediates a branch of the Planar cell polarity (PCP) signaling involved in tissue patterning, instructing cell polarity and cell polar organization within a tissue. PDZRN3 is expressed in the embryonic mouse heart then its expression dropped significantly postnatally corresponding with heart maturation and CM polarized elongation. A moderate CM overexpression of Pdzrn3 ( Pdzrn3 OE) during the first week of life, induced a severe eccentric hypertrophic phenotype with heart failure. In models of pressure-overload stress heart failure, CM-specific Pdzrn3 knockout showed complete protection against degradation of heart function. We reported that Pdzrn3 signaling induced PKC ζ expression, c-Jun nuclear translocation and a reduced nuclear ß catenin level, consistent markers of the planar non-canonical Wnt signaling in CM. We then show that subcellular localization (intercalated disk) of junction proteins as Cx43, ZO1 and Desmoglein 2 was altered in Pdzrn3 OE mice, which provides a molecular explanation for impaired CM polarization in these mice. Our results reveal a novel signaling pathway that controls a genetic program essential for heart maturation and maintenance of overall geometry, as well as the contractile function of CM, and implicates PDZRN3 as a potential therapeutic target for the prevention of human heart failure