Rôle du facteur de transcription HIF-1 dans la physiologie cutanée et dans la réponse à l'exposition UV

The transcription factor HIF-1 is a heterodimer composed of an and ß subunit. HIF-1 is capable of recognizing a consensus sequence called HRE (hypoxia Response Element) and regulate the expression of more than 200 target genes involved in various cellular mechanisms. We are interested in studying the role of HIF-1 in the skin physiology.Our results show that HIF-1 regulates the expression of two main factors (XPC and XPD) involved in nucleotide excision repair through binding on HRE in their promoter regions. Quantitative chromatin immunoprecipitation assays further revealed putative HREs in the genes encoding other DNA repair proteins (XPB, XPG, CSA and CSB), suggesting that HIF-1 is a key regulator of the DNA repair machinery. We proved that HIF-1 is essential for keratinocyte adhesion through its regulation exerted on laminin-332 and integrins (6, ß1). The lack of HIF-1 expression also prevents the reconstruction of epidermis by human keratinocytes. Our results showed that mice constitutively depleted for HIF-1 in their epidermis develop with age a phenotype of inflammation in several regions. These mice are very sensitive to the stress resulting from wound injury and UVB irradiation. HIF-1 depletion in the epidermis of inducible mice using tamoxifen results in a detachment of the epidermis in suprabasal layers. These mice die within two weeks after injection of tamoxifenLe facteur de transcription HIF-1 est un hétérodimère composé d'une sous-unité et d'une sous-unité ß. HIF-1 est capable de reconnaître une séquence consensus appelée HRE (HIF Response Element) et de réguler l'expression de plus de 200 gènes cibles impliqués dans divers mécanismes cellulaires. Nous nous intéressons à étudier le rôle de HIF-1 dans la peau, d'une part dans la régulation des enzymes de la réparation de l'ADN suite à l'irradiation UVB, d'autre part dans la physiologie cutanée.Nos résultats montrent bien que HIF-1 régule l'expression des gènes participant à la réparation de l'ADN (XPC et XPD). Ces gènes contiennent dans leurs régions promotrices des HRE de HIF-1. La quantification de l'immunoprécipitation de chromatine révèle des HRE putatifs dans les gènes codant pour d'autres protéines de la réparation de l'ADN (XPB, XPG, CSA et CSB), ce qui suggère que HIF-1 est un régulateur clé de la machinerie de réparation de l'ADN. Nous avons prouvé que HIF-1 est indispensable à l'adhésion des kératinocytes par sa régulation exercée sur la laminine-332 et les intégrines (6 et ß1). L'absence de l'expression de HIF-1 empêche aussi la reconstruction des épidermes à partir des kératinocytes humains. Nos résultats ont montré que les souris invalidées pour HIF-1 développent avec l'âge un phénotype d'inflammation dans plusieurs régions. Ces souris sont très sensibles au moindre stress consécutif à une blessure et une irradiation UVB. L'induction de l'inhibition de HIF-1 dans des souris inductibles avec le tamoxifène indique un détachement de l'épiderme au niveau des couches supra-basales. Ces souris meurent deux semaines après injection du tamoxifèn

Role of the transcription factor HIF-1α in skin physiology and response to UV exposure

Le facteur de transcription HIF-1 est un hétérodimère composé d’une sous-unité α et d’une sous-unité ß. HIF-1 est capable de reconnaître une séquence consensus appelée HRE (HIF Response Element) et de réguler l’expression de plus de 200 gènes cibles impliqués dans divers mécanismes cellulaires. Nous nous intéressons à étudier le rôle de HIF-1α dans la peau, d’une part dans la régulation des enzymes de la réparation de l’ADN suite à l’irradiation UVB, d’autre part dans la physiologie cutanée.Nos résultats montrent bien que HIF-1α régule l’expression des gènes participant à la réparation de l’ADN (XPC et XPD). Ces gènes contiennent dans leurs régions promotrices des HRE de HIF-1α. La quantification de l’immunoprécipitation de chromatine révèle des HRE putatifs dans les gènes codant pour d'autres protéines de la réparation de l'ADN (XPB, XPG, CSA et CSB), ce qui suggère que HIF-1α est un régulateur clé de la machinerie de réparation de l'ADN. Nous avons prouvé que HIF-1α est indispensable à l’adhésion des kératinocytes par sa régulation exercée sur la laminine-332 et les intégrines (α6 et ß1). L’absence de l’expression de HIF-1α empêche aussi la reconstruction des épidermes à partir des kératinocytes humains. Nos résultats ont montré que les souris invalidées pour HIF-1α développent avec l’âge un phénotype d’inflammation dans plusieurs régions. Ces souris sont très sensibles au moindre stress consécutif à une blessure et une irradiation UVB. L’induction de l’inhibition de HIF-1α dans des souris inductibles avec le tamoxifène indique un détachement de l’épiderme au niveau des couches supra-basales. Ces souris meurent deux semaines après injection du tamoxifèneThe transcription factor HIF-1 is a heterodimer composed of an α and ß subunit. HIF-1 is capable of recognizing a consensus sequence called HRE (hypoxia Response Element) and regulate the expression of more than 200 target genes involved in various cellular mechanisms. We are interested in studying the role of HIF-1α in the skin physiology.Our results show that HIF-1α regulates the expression of two main factors (XPC and XPD) involved in nucleotide excision repair through binding on HRE in their promoter regions. Quantitative chromatin immunoprecipitation assays further revealed putative HREs in the genes encoding other DNA repair proteins (XPB, XPG, CSA and CSB), suggesting that HIF-1α is a key regulator of the DNA repair machinery. We proved that HIF-1α is essential for keratinocyte adhesion through its regulation exerted on laminin-332 and integrins (α6, ß1). The lack of HIF-1α expression also prevents the reconstruction of epidermis by human keratinocytes. Our results showed that mice constitutively depleted for HIF-1α in their epidermis develop with age a phenotype of inflammation in several regions. These mice are very sensitive to the stress resulting from wound injury and UVB irradiation. HIF-1α depletion in the epidermis of inducible mice using tamoxifen results in a detachment of the epidermis in suprabasal layers. These mice die within two weeks after injection of tamoxife

Trisk 95 as a novel skin mirror for normal and diabetic systemic glucose level

International audienceDeveloping trustworthy, cost effective, minimally or non-invasive glucose sensing strategies is of great need for diabetic patients. In this study, we used an experimental type I diabetic mouse model to examine whether the skin would provide novel means for identifying biomarkers associated with blood glucose level. We first showed that skin glucose levels are rapidly influenced by blood glucose concentrations. We then conducted a proteomic screen of murine skin using an experimental in vivo model of type I diabetes and wild-type controls. Among the proteins that increased expression in response to high blood glucose, Trisk 95 expression was significantly induced independently of insulin signalling. A luciferase reporter assay demonstrated that the induction of Trisk 95 expression occurs at a transcriptional level and is associated with a marked elevation in the Fluo-4AM signal, suggesting a role for intracellular calcium changes in the signalling cascade. Strikingly, these changes lead concurrently to fragmentation of the mitochondria. Moreover, Trisk 95 knockout abolishes both the calcium flux and the mitochondrial phenotype changes indicating dependency of glucose flux in the skin on Trisk 95 function. The data demonstrate that the skin reacts robustly to systemic blood changes, and that Trisk 95 is a promising biomarker for a glucose monitoring assembly

Metabolic patterns of sweat-extracellular vesicles during exercise and recovery states using clinical grade patches

Background: Metabolite-based sensors are attractive and highly valued for monitoring physiological parameters during rest and/or during physical activities. Owing to their molecular composition consisting of nucleic acids, proteins, and metabolites, extracellular vesicles (EVs) have become acknowledged as a novel tool for disease diagnosis. However, the evidence for sweat related EVs delivering information of physical and recovery states remains to be addressed.Methods: Taking advantage of our recently published methodology allowing the enrichment and isolation of sweat EVs from clinical patches, we investigated the metabolic load of sweat EVs in healthy participants exposed to exercise test or recovery condition. -Ten healthy volunteers (-three females and -seven males) were recruited to participate in this study. During exercise test and recovery condition, clinical patches were attached to participants' skin, on their back. Following exercise test or recovery condition, the patches were carefully removed and proceed for sweat EVs isolation. To explore the metabolic composition of sweat EVs, a targeted global metabolomics profiling of 41 metabolites was performed.Results: Our results identified seventeen metabolites in sweat EVs. These are associated with amino acids, glutamate, glutathione, fatty acids, creatine, and glycolysis pathways. Furthermore, when comparing the metabolites' levels in sweat EVs isolated during exercise to the metabolite levels in sweat EVs collected after recovery, our findings revealed a distinct metabolic profiling of sweat EVs. Furthermore, the level of these metabolites, mainly myristate, may reflect an inverse correlation with blood glucose, heart rate, and respiratory rate levels.Conclusion: Our data demonstrated that sweat EVs can be purified using routinely used clinical patches during physical activity, setting the foundations for larger-scale clinical cohort work. Furthermore, the metabolites identified in sweat EVs also offer a realistic means to identify relevant sport performance biomarkers. This study thus provides proof-of-concept towards a novel methodology that will focus on the use of sweat EVs and their metabolic composition as a non-invasive approach for developing the next-generation of sport wearable sensors.Peer reviewe

Additional file 5: Figure S4. of Impairment of Wnt11 function leads to kidney tubular abnormalities and secondary glomerular cystogenesis

OPT-based kidney morphometric. Wnt11 knockout (C, C´) alters the volumetric measures such as the relative volumes of the kidney and pelvis relative to WT (B, B´). (A) OPT volumetry data (n = 6-8). Drishti reconstruction of the pelvis (B, C) and highlighted regions depicted as B´ and C´ (boxed areas in B, C) revealing the sagittal/rostro-caudal tubular view. Note that the Wnt11 deficiency led to considerable changes in the overall 3D arrangement of the tubules as well as the degree of their convolution when compared to control (compare C to B and C’ to B´). Bars: B, C 800 μm; B’, C’ 300 μm. (JPG 379 kb

Additional file 7: Table S2. of Impairment of Wnt11 function leads to kidney tubular abnormalities and secondary glomerular cystogenesis

Urine biochemistry test in Wnt11 -/- and WT mice. Creatinine clearance (ml/min) was calculated from the formula UV/P ×1/1440. U; urinary concentration of the substance (mmol/l), V; urinary volume (ml), P; plasma creatinine concentration (μmol), 1440: minutes in 24 h. Creatinine clearance and urine volume were scaled to body weight. (DOCX 18 kb

Additional file 6: Figure S5. of Impairment of Wnt11 function leads to kidney tubular abnormalities and secondary glomerular cystogenesis

Wnt11 deficiency influences kidney function. Creatinine clearance (A) is significantly reduced in the Wnt11 -/- mice when compared to WT, indicating reduced glomerular filtration rate (GFR). This situation corresponds to a diagnosis of mild to moderate renal failure in a human and is in line with the observed increase in blood urea nitrogen (BUN) (B) and reduced daily urine excretion (C). n = 8-10, p < 0.05. (JPG 146 kb

Additional file 2: Figure S1. of Impairment of Wnt11 function leads to kidney tubular abnormalities and secondary glomerular cystogenesis

Formation of glomerular cysts and anomalies of papillary duct due to Wnt11 deficiency. A and D) Note discrete glomerular changes in E16.5 as the Bowman’s capsule of the glomerulus is enlarged and contains parietal podocytes (compare D to A, red arrows). B and E) Advanced cystic formation is found in NB, the glomerular tuft has an abnormal architecture when compared to the WT (arrow) and it is microcystic (star). C and F) Typical findings in all adult Wnt11 -/- are cortical glomerular microcysts that contain rudiments of the tuft (F, G stars) and hypertrophied glomeruli (compare F to C, black arrows). In the severe kidney tubular anomalies of Wnt11 deficient mice interstitial fibrosis is noted (F, empty arrow). G) High magnification of a cortical glomerular cyst (star) with dysmorphic tuft (arrow) in the kidney of Wnt11 -/- mouse. H, I) TEM shows normal structure of non-cystic glomeruli in Wnt11 -/- mice (RBC: red blood cell; US: urinary space; M: mesangial cell; GBM: glomerular basement membrane). J-M) Immunohistochemistry with AQP2 in kidney indicates that AQP2 staining is more intense in Wnt11 deficient papillary ducts compared to controls (arrows). In contrast, the cell morphology of the cortical collecting duct was normal and expression of AQP2 is not different from controls (arrows). Bars: J, L 200 μm, A, D, C-G 100 μm, B, E, K, M 50 μm, H, I 2 μm. (JPG 1128 kb

Optical studies of nanodiamond-tissue interaction:skin penetration and localization

Abstract In this work, several optical-spectroscopic methods have been used to visualize and investigate the penetration of diamond nanoparticles (NPs) of various sizes (3–150 nm), surface structures and fluorescence properties into the animal skin in vitro. Murine skin samples have been treated with nanodiamond (ND) water suspensions and studied using optical coherence tomography (OCT), confocal and two-photon fluorescence microscopy and fluorescence lifetime imaging (FLIM). An analysis of the optical properties of the used nanodiamonds (NDs) enables the selection of optimal optical methods or their combination for the study of nanodiamond–skin interaction. Among studied NDs, particles of 100 nm in nominal size were shown to be appropriate for multimodal imaging using all three methods. All the applied NDs were able to cross the skin barrier and penetrate the different layers of the epidermis to finally arrive in the hair follicle niches. The results suggest that NDs have the potential for multifunctional applications utilizing multimodal imaging