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Any patient with a herpes zoster infection of the mandibular branch of the trigeminal nerve should benefit from early oral monitoring, especially in elderly population where traumatic dental prostheses are common, because osteonecrosis can occur., Herpes zoster infection is a rare and little‐known etiology of osteonecrosis of the maxilla. Only a few cases have reported in the international literature. We present a rare case of right mandibular osteonecrosis following herpes zoster infection in the mandibular branch of the trigeminal nerve.

Calcific aortic valve disease (CAVD) is a significant cause of illness and death worldwide. Identification of early predictive markers could help optimize patient management. RNA-sequencing was carried out on human fetal aortic valves at gestational weeks 9, 13, and 22 and on a case-control study with adult noncalcified and calcified bicuspid and tricuspid aortic valves. In dimension reduction and clustering analyses, diseased valves tended to cluster with fetal valves at week 9 rather than normal adult valves, suggesting that part of the disease program might be due to reiterated developmental processes. The analysis of groups of coregulated genes revealed predominant immune-metabolic signatures, including innate and adaptive immune responses involving lymphocyte T-cell metabolic adaptation. Cytokine and chemokine signaling, cell migration, and proliferation were all increased in CAVD, whereas oxidative phosphorylation and protein translation were decreased. Discrete immune-metabolic gene signatures were present at fetal stages and increased in adult controls, suggesting that these processes intensify throughout life and heighten in disease. Cellular stress response and neurodegeneration gene signatures were aberrantly expressed in CAVD, pointing to a mechanistic link between chronic inflammation and biological aging. Comparison of the valve RNA-sequencing data set with a case-control study of whole blood transcriptomes from asymptomatic individuals with early aortic valve calcification identified a highly predictive gene signature of CAVD and of moderate aortic valve calcification in overtly healthy individuals. These data deepen and broaden our understanding of the molecular basis of CAVD and identify a peripheral blood gene signature for the early detection of aortic valve calcification. This work was supported by the Ministerio de Ciencia, Innovacion y Universidades from Spain (MCIU) Grants SAF2016-78370-R, CB16/11/00399, CIBER CV, and RD16/0011/0021, TERCEL, Fundacion BBVA Grant BIO14_298, and Fundacion La Marato TV3 Grant 20153431 (to J.L.d.l.P.); and the Fondation Pour la Recherche Medicale Grant DPC20111123002 from l'Institut National de la Sante et de la Recherche Medicale and l'Association Francaise Contre les Myopathies Grant TRIM-RD) (to S.Z). The cost of this publication was supported in part with funds from the European Regional Development Fund. The CNIC is supported by the Ministerio de Ciencia, Innovacion y Universidades (MCIU), the Instituto de Salud Carlos III (ISCIII), and the Pro CNIC Foundation and is a Severo Ochoa Center of Excellence (Grant SEV-2015-0505). Sí

International audience; Endothelial cells covering the aortic and ventricular sides of the aortic valve leaflets are exposed to different stresses, in particular wall shear stress (WSS). Biomechanical stimuli actively regulate valve tissue structure and induce remodeling events leading to valve dysfunction. Endothelial to mesenchymal transformation (EndMT), for example, has been associated with aortic valve disease. The biomechanical response of cells at different sides of the leaflets has not been clearly characterized. To analyze the mechanical response of valve endothelial cells (VECs) we developed a unique fluid activation device that applies physiologically relevant pulsatile WSS. We characterized the morphology and function of adult porcine aortic VECs derived from the opposite sides of aortic valve leaflets following exposure to different pulsatile WSS. We found that elongation and orientation of cells in response to pulsatile WSS depends on their side of origin. Quantification of gene expression confirms phenotypic differences between aortic and ventricular VECs. Aortic VECs exposed to pulsatile WSS similar to that in vivo at the tip of aortic side of the valve leaflet upregulated pro-EndMT (ACTA2, Snail, TGFβ1) and inflammation (ICAM-1, VCAM-1) genes, whereas expression of endothelial markers like PECAM-1 was decreased. Conversely, ventricular-VECs showed strong increase of PECAM-1 expression and no activation of pro-EndMT marker. Finally, we found that stress-induced genes are upregulated in both cell types, at higher levels in ventricular compared to aortic VECs. Application of physiological shear stress levels using a fluid activation device therefore reveals functional differences in VECs derived from opposite sides of the aortic valve leaflets.

International audience; Available online xxxx Hemodynamic forces have been known for a long time to regulate cardiogenic processes such as cardiac valve development. During embryonic development in vertebrates, the outflow tract (OFT) adjacent to the ventricle comes under increasing hemodynamic load as cardiogenesis proceeds. Consequently, extracellular matrix components are produced in this region as the cardiac cushions form which will eventually give rise to the aortic valves. The proteoglycan AGGRECAN is a key component of the aortic valves and is frequently found to be deregulated in a variety of aortic valve diseases. Here we demonstrate that aggrecan expression in the OFT of developing zebrafish embryos is hemodynamically dependent, a process presumably mediated by mechanosensitive channels. Furthermore, knockdown or knockout of aggrecan leads to failure of the OFT to develop resulting in ste-nosis. Based on these findings we analysed the expression of AGGRECAN in human bicuspid aortic valves (BAV). We found that in type 0 BAV there was a significant reduction in the expression of AGGRECAN. Our data indicate that aggrecan is required for OFT development and when its expression is reduced this is associated with BAV in humans.

Among the aortic valve diseases, the bicuspid aortic valve (BAV) occurs when the aortic valve has two leaflets (cusps), rather than three, and represents the most common form of congenital cardiac malformation, affecting 1&ndash, 2% of the population. Despite recent advances, the etiology of BAV is poorly understood. We have recently shown that Krox20 is expressed in endothelial and cardiac neural crest derivatives that normally contribute to aortic valve development and that lack of Krox20 in these cells leads to aortic valve defects including partially penetrant BAV formation. Dysregulated expression of endothelial nitric oxide synthase (Nos3) is associated with BAV. To investigate the relationship between Krox20 and Nos3 during aortic valve development, we performed inter-genetic cross. While single heterozygous mice had normal valve formation, the compound Krox20+/&minus, Nos3+/&minus, mice had BAV malformations displaying an in vivo genetic interaction between these genes for normal valve morphogenesis. Moreover, in vivo and in vitro experiments demonstrate that Krox20 directly binds to Nos3 proximal promoter to activate its expression. Our data suggests that Krox20 is a regulator of nitric oxide in endothelial-derived cells in the development of the aortic valve and concludes on the interaction of Krox20 and Nos3 in BAV formation.

Introduction Bicuspid aortic-valve (BAV) is the most common congenital malformation. Complications include aortic stenosis and regurgitation, endocarditis, aortic dilatation and dissection. Although BAV is associated with early valve degeneration, its pathophysiology remains unknown. Purpose The objective of this study was to examine at clinical, histological and molecular levels, a cohort of BAV patients with pure aortic regurgitation (AR-BAV). Methods From 2011 to 2018, patients with BAV were prospectively included. We performed histological and transcriptomic analysis of explanted BAV and compared differences between characteristics of prolapsed leaflet and non-prolapsed leaflet, using a normal tricuspid valve leaflet at reference. Aortic-valves from patients with long term left ventricular assist device (LVAD) were used as a model of acquired aortic regurgitation. Results A total of 350 patients with BAV were included. Among 316 patients (90%) with dysfunctional BAV, 66 (21%) presented severe AR-BAV. Mechanism of AR was prolapse in 37 patients (56%). Histologically, analysis of 2 explanted AR-BAV showed disorganization of extracellular matrix, loss of laminar structure and proteoglycans accumulation on prolapsed leaflet. Inversely, trilaminar structure of the non-prolapsed aortic leaflet was preserved. Transcriptomic analysis revealed upregulation of genes involved in extracellular matrix homeostasis and downregulation of endothelial cell markers on the prolapsed leaflet. The aortic-valve LVAD analysis found histological and molecular results similar to those described in BAV prolapsed leaflet and was associated with occurrence AR. Conclusion AR-BAV is a mood of BAV dysfunction that occurs in young male subjects, as a consequence of myxomatous degeneration similar to that described in mitral valve prolapse. LVAD model suggests that altered hemodynamic environment could account for the acquired nature of valve degeneration.

Genetically modified mice have advanced our understanding of valve development and related pathologies. Yet, little is known regarding human valvulogenesis in health and diseases. Genuine humanin vitromodels that reproduce valvular (patho)biology are thus needed. We here developed a human pluripotent stem cell-derived model fit to decode the early steps of human valvulogenesis and to recapitulate valve disease traits in a dish.Using cellular based, single cell omics-informed andin vivo-validated approaches, we derived a population of pre-valvular endocardial cells from a pluripotent stem cell source. These human prevalvular cells (HPVCs) expressed gene patterns conforming to the atrio-ventricular canal (AVC) endocardium signature originally established in E9.0 mouse embryos. In fact, HPVC treated with BMP2, cultured onto mouse AVC cushions, or transplanted into the AVC of embryonic mouse hearts, underwent endothelial-to-mesenchymal transition and expressed markers of valve interstitial cells of different valvular layers demonstrating tissue functionality. HPVCs also differentiated into tendinous/chondrogenic cells in line with the valvular repertoire. Extending this valvulogenic model to patient specific iPS cells, we recapitulated features of mitral valve prolapse and uncovered that dysregulation of the SHH pathway is likely to be at the origin of the disease thus providing a putative therapeutic target.Human pluripotent stem cells recapitulate early valvulogenesis and provide a powerful model to systematically decipher the origin and lineage contribution of different valvular cell types in humans as well as to study valve diseases in a dish.

International audience; Although cardiac neural crest cells are required at early stages of arterial valve development, their contribution during valvular leaflet maturation remains poorly understood. Here, we show in mouse that neural crest cells from pre-otic and post-otic regions make distinct contributions to the arterial valve leaflets. Genetic fate-mapping analysis of Krox20-expressing neural crest cells shows a large contribution to the borders and the interleaflet triangles of the arterial valves. Loss of Krox20 function results in hyperplastic aortic valve and partially penetrant bicuspid aortic valve formation. Similar defects are observed in neural crest Krox20-deficient embryos. Genetic lineage tracing in Krox20(-/-) mutant mice shows that endothelial-derived cells are normal, whereas neural crest-derived cells are abnormally increased in number and misplaced in the valve leaflets. In contrast, genetic ablation of Krox20-expressing cells is not sufficient to cause an aortic valve defect, suggesting that adjacent cells can compensate this depletion. Our findings demonstrate a crucial role for Krox20 in arterial valve development and reveal that an excess of neural crest cells may be associated with bicuspid aortic valve.

Background: Retinoic acid (RA), the bioactive derivative of vitamin A, is essential for vertebrate heart development. Both excess and reduced RA signaling lead to cardiovascular malformations affecting the outflow tract (OFT). To address the cellular mechanisms underlying the effects of RA signaling during OFT morphogenesis, we used transient maternal RA supplementation to rescue the early lethality resulting from inactivation of the murine retinaldehyde dehydrogenase 2 (Raldh2) gene. Results: By embryonic day 13.5, all rescued Raldh2(-/-) hearts exhibit severe, reproducible OFT septation defects, although wild-type and Raldh2(+/-) littermates have normal hearts. Cardiac neural crest cells (cNCC) were present in OFT cushions of Raldh2(-/-) mutant embryos but ectopically located in the periphery of the endocardial cushions, rather than immediately underlying the endocardium. Excess mesenchyme was generated by Raldh2(-/-) mutant endocardium, which displaced cNCC derivatives from their subendocardial, medial position. Conclusions: RA signaling affects not only cNCC numbers but also their position relative to endocardial mesenchyme during the septation process. Our study shows that inappropriate coordination between the different cell types of the OFT perturbs its morphogenesis and leads to a severe congenital heart defect, persistent truncus arteriosus. Developmental Dynamics 245:388-401, 2016. (c) 2015 Wiley Periodicals, Inc.

International audience; 6p25 deletion is a rare but well-known entity. The main clinical features include an abnormal facial appearance, developmental delay, and ocular anomalies. Cardiac anomalies are frequently seen but remain poorly delineated. We describe a 4-year-old girl with 6p25.3 deletion, which includes the FOXC1 gene, typical dysmorphic features associated with developmental delay and oculo-motor anomalies. Aortic valve dysplasia was diagnosed early in life. The cardiac lesion progressed very rapidly between the age of 3 and 4 years requiring aortic valve replacement. Genomic analysis of blood and excised valve tissue showed down-regulation of FOXC1 but also FOXC2 expression in the diseased aortic valve. This allows us to speculate on the potential role of FOXC1 in aortic valve anomalies.

International audience; The GC-rich Binding Factor 2/Leucine Rich Repeat in the Flightless 1 Interaction Protein 1 gene (GCF2/LRRFIP1) is predicted to be alternatively spliced in five different isoforms. Although important peptide sequence differences are expected to result from this alternative splicing, to date, only the gene transcription regulator properties of LRRFIP1-Iso5 were unveiled. Based on molecular, cellular and biochemical data, we show here that the five isoforms define two molecular entities with different expression profiles in human tissues, subcellular localizations, oligomerization properties and transcription enhancer properties of the canonical Wnt pathway. We demonstrated that LRRFIP1-Iso3, -4 and -5, which share over 80% sequence identity, are primarily located in the cell cytoplasm and form homo and hetero-multimers between each other. In contrast, LRRFIP1-Iso1 and -2 are primarily located in the cell nucleus in part thanks to their shared C-terminal domain. Furthermore, we showed that LRRFIP1-Iso1 is preferentially expressed in the myocardium and skeletal muscle. Using the in vitro Topflash reporter assay we revealed that among LRRFIP1 isoforms, LRRFIP1-Iso1 is the strongest enhancer of the β-catenin Wnt canonical transcription pathway thanks to a specific N-terminal domain harboring two critical tryptophan residues (W76, 82). In addition, we showed that the Wnt enhancer properties of LRRFIP1-Iso1 depend on its homo-dimerisation which is governed by its specific coiled coil domain. Together our study identified LRRFIP1-Iso1 as a critical regulator of the Wnt canonical pathway with a potential role in myocyte differentiation and myogenesis.

Background The physiopathology of bicuspid aortic valve (BAV) degeneration remains unknown. Altered hemodynamic environment could favor valve degeneration. Aim (1) To compare clinical and echocardiographic data of normally functioning and dysfunctional BAV; and (2) to correlate BAV phenotype to valve function. Methods Consecutive patients with normally functioning (NF-BAV) or dysfunctional BAV (D-BAV) were prospectively included. Sievers’ classification was used to compare BAV regarding valve function. Results A total of 223 patients with BAV were prospectively included. Mean age was 52.9 ± 16.5 years with a male predominance (n = 168, 75.3%). Twenty-four patients had NF-BAV and 199 patients had D-BAV. One hundred and seventy-eight patients (82.4%) had a Sievers’ type 1 BAV, mainly with an intercoronary leaflet fusion (n = 155, 87.1%). BAV aortopathy was found in 86 patients (38.5%). By multivariable analysis, age > 50 years (5.5 [2.2–17.4], P = 0.0006), male gender (3.4 [1.2–9.3], P = 0.01) and the presence of a raphe (3.6 [1.2–9.9], P = 0.01) were significantly associated with BAV dysfunction. Among D-BAV, 68 patients (34%) had AS and 91 patients (45%) had AR. Multivariate analysis revealed that a higher age (1.9 [1.85–1.94], P Fig. 1 ). Conclusions Commissural fusion of aortic cusps is associated with BAV dysfunction. By altering aortic blood flow and stiffening fused leaflet, the raphe could accelerate valve degeneration. These results suggested the emerging role of mechanobiology in BAV degeneration.

Catechols represent an important and versatile building block for the design of mussel-inspired synthetic adhesives and coatings. Indeed, their ability to establish large panoply of interactions with both organic and inorganic substrates has promoted catechol as a universal anchor for surface modifications. In addition to its pivotal role in adhesive interfaces, the catechol unit recently emerged as a powerful building block for the preparation of a large range of polymeric materials with intriguing structures and fascinating properties. The importance of catechols as efficient anchoring groups has been highlighted in recent excellent reviews partly dedicated to the characterization of their adhesive mechanisms onto surfaces and to their applications. The aim of this paper is to review for the first time the main synthetic approaches developed for the design of novel catechol-based polymer materials. We will also highlight the importance of these groups as versatile platforms for further functionalization of the macromolecular structures, but also surfaces. This will be illustrated by briefly discussing some advanced applications developed from these catechol-modified polymers. The review is organized according to the chemical structure of the functionalized catechol polymers. Chapter 1 discusses polymers bearing catechols embedded into the polymer main chain. Chapter 2 focuses on the attachment of catechol moieties as pendant groups and Chapter 3 describes the different approaches for incorporation of the catechol unit at the extremity of well-defined polymers.

International audience; Background. - The mechanism involved in the onset of aortic valve (AoV) disease remains unclear despite its poor prognosis and frequency. Recently, we reported that Krox20 (EGR2 in humans) is involved in AoV development and dysfunction. Aim. - Analyze Krox20 heterozygous mice (Krox20(+/-)) to discover whether incomplete expression of Krox20 can cause valvular diseases. Methods. - Transcriptional levels of Col1a2/COL1A2 and Krox20/EGR2 in AoVs from Krox20(+/-) mice and human patients operated on for severe aortic regurgitation were evaluated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Human control valves were obtained from three transplanted patients without AoV disease. Twenty-one heterozygous Krox20(+/-) mice were compared with 35 controls at different ages. Three independent measurements of valve thickness were performed on magnified tissue sections using Image J software. In vivo valve structure and function were evaluated using the high-frequency Vevo (R) 2100 echocardiogram. Results. - qRT-PCR analysis using AoVs from patients with severe aortic regurgitation showed a decrease in EGR2 expression associated with significant downregulation of COL1A2 expression (P < 0.05). Similar results were observed in the AoVs of Krox20(+/-) mice. Anatomical examination revealed that incomplete invalidation of Krox20 caused significant thickening of the aortic leaflet compared with controls (145 +/- 22 vs. 75 +/- 24 mu m; P=0.01). Within the mutant group, this thickening worsened significantly over time (Krox20(+/-) mice aged >7 vs. < 7 months: 136 +/- 48 vs. 102 +/- 41 mu m; P

International audience; DiGeorge syndrome (DGS) is a congenital disease causing cardiac outflow tract anomalies, craniofacial dysmorphogenesis, thymus hypoplasia, and mental disorders. It results from defective development of neural crest cells (NCs) that colonize the pharyngeal arches and contribute to lower jaw, neck and heart tissues. Although TBX1 has been identified as the main gene accounting for the defects observed in human patients and mouse models, the molecular mechanisms underlying DGS etiology are poorly identified. The recent demonstrations that the SDF1/CXCR4 axis is implicated in NC chemotactic guidance and impaired in cortical interneurons of mouse DGS models prompted us to search for genetic interactions between Tbx1, Sdf1 (Cxcl12) and Cxcr4 in pharyngeal NCs and to investigate the effect of altering CXCR4 signaling on the ontogeny of their derivatives, which are affected in DGS. Here, we provide evidence that Cxcr4 and Sdf1 are genetically downstream of Tbx1 during pharyngeal NC development and that reduction of CXCR4 signaling causes misrouting of pharyngeal NCs in chick and dramatic morphological alterations in the mandibular skeleton, thymus and cranial sensory ganglia. Our results therefore support the possibility of a pivotal role for the SDF1/CXCR4 axis in DGS etiology.

A bio-inspired durable anti-biofilm coating was developed for industrial stainless steel (SS) surfaces. Two polymers inspired from the adhesive and cross-linking properties of mussels were designed and assembled from aqueous solutions onto SS surfaces to afford durable coatings. Trypsin, a commercially available broad spectrum serine protease, was grafted as the final active layer of the coating. Its proteolytic activity after long immersion periods was demonstrated against several substrata, viz. a synthetic molecule, N-α-benzoyl-DL-arginine-p-nitroanilide hydrochloride (BAPNA), a protein, FTC-casein, and Gram-positive biofilm forming bacterium Staphylococcus epidermidis.

The goal of this paper was to establish the durability profile of antibacterial multilayer thin films under storage and usage conditions. Thin films were built on stainless steel (SS) by means of a layer-by-layer process alternating a negatively charged polyelectrolyte, polyacrylic acid, with a cationic antibacterial peptide, nisin. SS coupons coated with the antibacterial film were challenged under environmental and usage conditions likely to be encountered in real-world applications. The change in antibacterial activity elicited by the challenge was used as an indicator of multilayer film resistance. Antibacterial SS samples could be stored for several weeks at 4°C in ambient air and antibacterial films were resistant to dipping and mild wiping in water and neutral detergent. The multilayer coating showed some weaknesses, however, that need to be addressed.

Retinoic acid (RA), the bioactive derivative of vitamin A, is essential for vertebrate heart development. Both excess and reduced RA signaling lead to cardiovascular malformations affecting the outflow tract (OFT). To address the cellular mechanisms underlying the effects of RA signaling during OFT morphogenesis, we used transient maternal RA supplementation to rescue the early lethality resulting from inactivation of the murine retinaldehyde dehydrogenase 2 (Raldh2) gene.By embryonic day 13.5, all rescued Raldh2(-/-) hearts exhibit severe, reproducible OFT septation defects, although wild-type and Raldh2(+/-) littermates have normal hearts. Cardiac neural crest cells (cNCC) were present in OFT cushions of Raldh2(-/-) mutant embryos but ectopically located in the periphery of the endocardial cushions, rather than immediately underlying the endocardium. Excess mesenchyme was generated by Raldh2(-/-) mutant endocardium, which displaced cNCC derivatives from their subendocardial, medial position.RA signaling affects not only cNCC numbers but also their position relative to endocardial mesenchyme during the septation process. Our study shows that inappropriate coordination between the different cell types of the OFT perturbs its morphogenesis and leads to a severe congenital heart defect, persistent truncus arteriosus.

International audience; AIMS: Heart valve maturation is achieved by the organization of extracellular matrix (ECM) and the distribution of valvular interstitial cells. However, the factors that regulate matrix components required for valvular structure and function are unknown. Based on the discovery of its specific expression in cardiac valves, we aimed to uncover the role of Krox20 (Egr-2) during valve development and disease. METHODS AND RESULTS: Using series of mouse genetic tools, we demonstrated that loss of function of Krox20 caused significant hyperplasia of the semilunar valves, while atrioventricular valves appeared normal. This defect was associated with an increase in valvular interstitial cell number and ECM volume. Echo Doppler analysis revealed that adult mutant mice had aortic insufficiency. Defective aortic valves (AoVs) in Krox20(-/-) mice had features of human AoV disease, including excess of proteoglycan deposition and reduction of collagen fibres. Furthermore, examination of diseased human AoVs revealed decreased expression of KROX20. To identify downstream targets of Krox20, we examined expression of fibrillar collagens in the AoV leaflets at different stages in the mouse. We found significant down-regulation of Col1a1, Col1a2, and Col3a1 in the semilunar valves of Krox20 mutant mice. Utilizing in vitro and in vivo experiments, we demonstrated that Col1a1 and Col3a1 are direct targets of Krox20 activation in interstitial cells of the AoV. CONCLUSION: This study identifies a previously unknown function of Krox20 during heart valve development. These results indicate that Krox20-mediated activation of fibrillar Col1a1 and Col3a1 genes is crucial to avoid postnatal degeneration of the AoV leaflets.

ObjectiveThe mechanism involved in the onset of aortic valve (AoV) disease remains unclear.Our recent work revealed the requirement of the transcription factor Krox20 (EGR2) to regulate fibrillar collagen genes during AoV formation. Based on 50% decreased expression of KROX20/EGR2 in diseased human AoV, we examined the phenotype of the Krox20 heterozygous mice with echo and histological analyses.MethodsKrox20-/+heterozygous mice (n=21) were compared to control (n=35) at different stages. Quantitative analysis of AoV histology was performed intriplicate for each genotype. We used a high-frequency echocardio-gram to evaluate the AoV function.ResultsWe demonstrated that incomplete invalidation of Krox20 in mutant mice caused a significant thickening of AoV compared to control group (145±22µm vs 75±24µm, p=0.01). Within the heterozygous group, we observed that is thickening involved exclusively the AoV and worsened significantly during time (>7 month-old vs

α6β4 integrin is the main component of hemidesmosomes (HD) that stably anchor the epithelium to the underlying basement membrane. Epithelial cell migration requires HD remodelling which can be promoted by epidermal growth factor (EGF). We previously showed that extracellular nucleotides inhibit growth factor-induced keratinocyte migration. Here, we investigate the effect of extracellular nucleotides on α6β4 integrin localisation in HD during EGF-induced cell migration. Using a combination of pharmacological inhibition and gene silencing approaches, we report that UTP activates the P2Y2 purinergic receptor and Gαq protein to inhibit EGF/ERK1/2-induced cell migration in keratinocytes. Using a keratinocyte cell line expressing an inducible form of the Raf kinase, we show that UTP inhibits the EGF-induced ERK1/2 pathway activation downstream of Raf. Moreover, we establish that ERK1/2 activation by EGF leads to the mobilization of α6β4 integrin from HD. Importantly, activation of P2Y2R and Gαq by UTP promotes HD formation and protects these structures from EGF-triggered dissolution as revealed by confocal analysis of the distribution of α6β4 integrin, plectin, BPAG1, BPAG2 and CD151 in keratinocytes. Finally, we show that the activation of p90RSK, downstream of ERK1/2, is sufficient to promote EGF-mediated HD dismantling and that UTP does not stabilise HD in cells expressing an activated form of p90RSK. Our data underline an unexpected role of P2Y2R and Gαq in the inhibition of ERK1/2 signalling pathway and in the modulation of hemidesmosome dynamics and keratinocyte migration.

In this study, we report on the original synthesis and characterization of novel antimicrobial coatings for stainless steel by alternating the deposition of aqueous solutions of positively charged polyelectrolyte micelles doped with silver-based nanoparticles with a polyanion. The micelles are formed by electrostatic interaction between two oppositely charged polymers: a polycation bearing 3,4-dihydroxyphenylalanine units (DOPA, a major component of natural adhesives) and a polyanion (poly(styrene sulfonate), PSS) without using any block copolymer. DOPA units are exploited for their well-known ability to anchor to stainless steel and to form and stabilize biocidal silver nanoparticles (Ag(0)). The chlorine counteranion of the polycation forms and stabilizes biocidal silver chloride nanoparticles (AgCl). We demonstrate that two layers of micelles (alternated by PSS) doped with silver particles are enough to impart to the surface strong antibacterial activity against gram-negative E. coli. Moreover, micelles that are reservoirs of biocidal Ag(+) can be easily reactivated after depletion. This novel water-based approach is convenient, simple, and attractive for industrial applications.

Heart valves diseases affect 3% of world population, and surgery is often the only therapeutic mean. A genetic study performed on a family in which several members exhibited a MVP identified a R94G mutation on LRRFip1 gene. LRRFip1 alternative transcription splicing gives rise to five isoforms in humans, three of which are targeted by the mutation (Iso1, 3 and 4). Previous studies only focused on LRRFip1-iso5 that was first described as a transcription factor interacting with positive (Dishevelled) and negative (Flightless-1) regulators of the canonical Wnt β-catenin dependant pathway. As it may participate and regulate crucial events of cardiac valve development and homeostasis involving Wnt pathway, we hypothesised that LRRFip1 could be involved in MVP pathology. We first analysed the expression of LRRFip1 in valves by RNA sequencing and quantitative PCR and showed that LRRFip1- iso1 is expressed in human valves. In mouse, it prevails during embryonic development and then levels down to that other isoforms expression. We thus focused on LRRFip-iso1. Using cell fractionation, we showed a nuclear localization of LRRFip1-iso1 while other isoforms are strictly cytoplasmic. Using luciferase-based Wnt reporter assays and co-IP, we further demonstrated that out of the five isoforms, LRRFip1-iso1 is the strongest interactor of Dvl-1 and Fli-1, and the strongest activator of the canonical Wnt pathway. Although activation requires beta-catenin, it does not involve beta-catenin stabilization nor activation. Using site directed mutagenesis, we mapped the domain responsible for Wnt pathway activation to the 25 amino-acids region surrounding arginine 94 and showed that R94G mutation also decreases Wnt activation. This work demonstrates the involvement of LRRFip1-iso1 in canonical Wnt pathway activation. Taken together, our results suggest a potential role for LRRFip1 in valvulogenesis and/or valve homeostasis regulation that may be impeded by the R94G mutation.

We report on the original synthesis of a poly(methacrylamide) bearing (oxidized) 3,4-dihydroxyphenylalanine specially designed to (i) insure film growth by covalent coupling, (ii) covalently bind an antibacterial peptide and (iii) contribute to the film cross-linking that is essential for the durability of the properties.

International audience; Here we report on an all-in-one approach to prepare robust antimicrobial films on stainless steel. The strategy is based on the layer-by-layer deposition of polyelectrolytes. A polycationic copolymer bearing 3,4-dihydroxyphenylalanine units (DOPA, a major component of natural adhesives) was synthesized and co-deposited with precursors of silver nanoparticles as the first layer. The presence of DOPA units ensures a strong anchoring on the stainless steel substrate, and the silver nanoparticles are sources of biocidal Ag+, providing stainless steel with antimicrobial activity. We show that multilayered films, obtained by alternating this nanoparticle-loaded polycationic copolymer with polystyrene sulfonate, a commercial polyanion, results in stainless steel with high antibacterial activity against Gram-negative E. coli bacteria. The polycationic layers are a reservoir of Ag+ that can be reactivated after depletion. The whole process of film formation, including the synthesis of the copolymer, is conducted in aqueous media under very mild conditions, which makes it very attractive for industrial scale-up and sustainable applications.