therapeutic targeting of the receptor complex of elastin in tumoral invasion. Mechanistic aspect and impact of age.

L'élastine est la protéine de la matrice extracellulaire responsable de l'élasticité des tissus. Elle est synthétisée en abondance dans les tissus soumis à de fortes contraintes mécaniques tels que la peau, les poumons, et les artères. Ce biopolymère présente une demi-vie longue de 70 ans et est par conséquent sujet aux altérations liées à l'âge. De plus, l'élastine est dégradée lors de la progression tumorale, notamment celle du mélanome. Sa dégradation entraîne la libération de peptides dérivés de l'élastine (EDP) dotés d'activités biologiques propres et pouvant être impliqués dans l'invasion tumorale (prolifération, angiogenèse, sécrétion de protéases, invasion, survie). Nous avons été les premiers à démontrer que les EDP sont capables de fortement promouvoir le développement de mélanome in vivo dans un modèle murin au travers de l'augmentation de la prolifération et de l'invasion des cellules tumorales impliquant la collagènase-1 ou MMP-1. Ces données suggèrent ainsi que le récepteur de ces peptides, le complexe récepteur de l'élastine (CRE), pourrait constituer une cible thérapeutique innovante afin de lutter contre ce cancer pour lequel un manque flagrant de thérapies efficientes prévaut à l'heure actuelle. Dans le cadre de cette étude, nous avons développé différentes stratégies thérapeutiques basées sur le ciblage du récepteur CRE. Nous démontrons pour la première fois que le ciblage thérapeutique du CRE permet de limiter de manière efficace la progression du mélanome in vitro et in vivo dans un modèle murin. De plus, le vieillissement étant un des facteurs de risque majeur du mélanome, nous avons évalué l'impact de l'âge du stroma sur les effets des EDP et le développement tumoral associé.Elastin is the extracellular matrix protein responsible for tissue elasticity. It is abundant in tissues experiencing important mechanical constraints such as skin, lungs and arteries. This biopolymer possesses a half-life of 70 years and, consequently, it is subjected to age-related alterations. Moreover, elastin is degraded during tumor progression, notably that of melanoma. Its degradation results in the release of elastin-derived peptides (EDP) which possess their own biological activities that can be linked to tumor invasion (proliferation, angiogenesis, proteases secretion, invasion, survival). We have been the first to show that EDP can promote melanoma development in an in vivo mouse model by raising the proliferation and invasion of tumor cells through collagenase-1 (MMP-1) up-regulation. These data thus suggest that the receptor for these peptides, the elastin receptor complex, could constitute a novel therapeutic target to fight against this type of cancer for which no therapies are efficient now. In this study, we have developed therapeutic strategies targeting the ERC complex. We show for the first time that the therapeutic targeting of the ERC could efficiently limit melanoma progression in an in vitro and in vivo murine model. Additionally, as aging is one of melanoma major risk factors, we have evaluated the impact of stromal age on EDP effects and the associated tumor development

Silymarin Alleviates Oxidative Stress and Inflammation Induced by UV and Air Pollution in Human Epidermis and Activates β-Endorphin Release through Cannabinoid Receptor Type 2

Background: Skin is exposed to ultraviolet radiation (UV) and air pollution, and recent works have demonstrated that these factors have additive effects in the disturbance of skin homeostasis. Nuclear-factor-erythroid-2-related factor 2 (Nrf2) and aryl hydrocarbon receptor (AHR) appear to be appropriate targets in the management of combined environmental stressors. The protective effects of silymarin (SM), an antioxidant and anti-inflammatory complex of flavonoids, were evaluated. Methods: Reactive oxygen species (ROS) and interleukin 1-alpha (IL-1a) were quantified in UV+urban-dust-stressed reconstructed human epidermis (RHE) treated with SM. A gene expression study was conducted on targets related to AHR and Nrf2. SM agonistic activity on cannabinoid receptor type 2 (CB2R) was evaluated on mast cells. The clinical study quantified the performance of SM and cannabidiol (CBD) in skin exposed to solar radiation and air pollution. Results: SM decreased morphological alterations, ROS, and IL-1a in UV+urban-dust-stressed RHE. AHR- and Nrf2-related genes were upregulated, which control the antioxidant effector and barrier function. Interleukin 8 gene expression was decreased. The clinical study confirmed SM improved the homogeneity and perceived well-being of urban skins exposed to UV, outperforming CBD. SM activated CB2R and the release of β-endorphin from mast cells. Conclusions: SM provides protection of skin from oxidative stress and inflammation caused by two major factors of exposome and appears mediated by AHR-Nrf2. SM activation of CB2R is opening a new understanding of SM’s anti-inflammatory properties

The Natural <i>Centella asiatica</i> Extract Acts as a Stretch Mark Eraser: A Biological Evaluation

Stretch marks are far from exclusively appearing on pregnant women and appear whenever the body experiences rapid growth. Collagen fibres are altered in the dermis, which is associated with a loss of orientation, and the elastic network is disrupted, leading to a fibrotic organisation. This results in epidermal tearing that produces skin lesions. Centella asiatica (CAST) is a well-known medicinal plant rich in active triterpenic molecules and traditionally used to treat wounds and help skin repair. The aim of this study was to evaluate CAST extract as a natural way to solve stretch mark concerns and understand its mechanism of action. Fibroblast proliferation based on scratch assay model and their gene expression by RT-qPCR was first evaluated. At the ex vivo level, elastin fibres were quantified by immunofluorescence. The orientation of the collagen fibres and their occupation of the dermis were analysed after Sirius red staining and specific software analysis. We showed that CAST stimulated fibroblast proliferation and reduced extracellular matrix degradation and fibrosis. On a stretch-marked skin explant, CAST increased the occupation of collagen fibres and elastin production. Based on the mechanisms behind the formation of stretch marks, CAST restored the dermis network by optimising fibre organisation for a visible skin remodelling effect

Global Repigmentation Strategy of Grey Hair Follicles by Targeting Oxidative Stress and Stem Cells Protection

One of the most visible signs of hair ageing is greying of the hair, also known as canities. This hair disorder is mainly caused by oxidative stress. In preliminary work, we designed various models mimicking the impact of oxidative stress on hair pigmentation, showing an accumulation of reactive oxygen species (ROS) production and a decrease in the presence of melanocytes and melanoblasts, resulting in a decrease in hair pigmentation. A proteomic study on skin scalp explants was performed to identify the dysregulated biological pathways related to canities. We developed a smart active ingredient which has been tested on these biological pathways. We demonstrated that these negative effects were rectified in the presence of the ingredient, showing a reduction of ROS, protection of melanocyte reservoirs and reactivation of hair pigmentation. Finally, a clinical study was carried out on a panel of 44 male volunteers with grey hair. After 4 months, we evidenced a reduction in the proportion of grey hair and in the number of grey hairs/cm2 relative to Day 0. In conclusion, we clearly evidenced that oxidative stress is a key factor in triggering a cascade of events leading to a loss of hair pigmentation. We developed this active ingredient which is capable of restoring all the disrupted mechanisms and of providing hair repigmentation within only 4 months

Zebiriosides A-L, oleanane saponins from the roots of Dendrobangia boliviana

International audienceTwelve oleanane saponins, zebiriosides A-L, were isolated from the roots of Dendrobangia boliviana Rusby, together with two known saponins, talunumoside I and 3-O-beta-D-glucuronopyranosyl serjanic acid. These saponins are glycosides of serjanic or phytolaccinic acid. Their structures were established on two basis: first, their spectral data, mainly HR-TOFESIMS, 1D-NMR (H-1, C-13, DEPT) and 2D-NMR (H-1-H-1 COSY, TOCSY, HSQC, HMBC, and ROESY), and second by comparison with literature data. These compounds were evaluated for their cytotoxic, antileishmanial and hemolytic activities. No antileishmanial or hemolytic activities were revealed, however zebirioside C and zebirioside I showed cytotoxicity against fibroblasts with IC50 of 6.4 and 5.6 mu M, respectively

GABA and GABA-Alanine from the Red Microalgae Rhodosorus marinus Exhibit a Significant Neuro-Soothing Activity through Inhibition of Neuro-Inflammation Mediators and Positive Regulation of TRPV1-Related Skin Sensitization

The aim of the present study was to investigate the neuro-soothing activity of a water-soluble hydrolysate obtained from the red microalgae Rhodosorus marinus Geitler (Stylonemataceae). Transcriptomic analysis performed on ≈100 genes related to skin biological functions firstly revealed that the crude Rhodosorus marinus extract was able to significantly negatively modulate specific genes involved in pro-inflammation (interleukin 1α encoding gene, IL1A) and pain detection related to tissue inflammation (nerve growth factor NGF and its receptor NGFR). An in vitro model of normal human keratinocytes was then used to evaluate the ability of the Rhodosorus marinus extract to control the release of neuro-inflammation mediators under phorbol myristate acetate (PMA)-induced inflammatory conditions. The extract incorporated at 1% and 3% significantly inhibited the release of IL-1α and NGF secretion. These results were confirmed in a co-culture system of reconstructed human epithelium and normal human epidermal keratinocytes on which a cream formulated with the Rhodosorus marinus extract at 1% and 3% was topically applied after systemic induction of neuro-inflammation. Finally, an in vitro model of normal human astrocytes was developed for the evaluation of transient receptor potential vanilloid 1 (TRPV1) receptor modulation, mimicking pain sensing related to neuro-inflammation as observed in sensitive skins. Treatment with the Rhodosorus marinus extract at 1% and 3% significantly decreased PMA-mediated TRPV1 over-expression. In parallel with these biological experiments, the crude Rhodosorus marinus extract was fractionated by centrifugal partition chromatography (CPC) and chemically profiled by a recently developed 13C NMR-based dereplication method. The CPC-generated fractions as well as pure metabolites were tested again in vitro in an attempt to identify the biologically active constituents involved in the neuro-soothing activity of the Rhodosorus marinus extract. Two active molecules, namely, γ-aminobutyric acid (GABA) and its structural derivative GABA-alanine, demonstrated a strong capacity to positively regulate skin sensitization mechanisms related to the TRPV1 receptors under PMA-induced inflammatory conditions, therefore providing interesting perspectives for the treatment of sensitive skins, atopia, dermatitis, or psoriasis

Uncoupling of Elastin Complex Receptor during In Vitro Aging Is Related to Modifications in Its Intrinsic Sialidase Activity and the Subsequent Lactosylceramide Production

International audienceDegradation of elastin leads to the production of elastin-derived peptides (EDP), which exhibit several biological effects, such as cell proliferation or protease secretion. Binding of EDP on the elastin receptor complex (ERC) triggers lactosylceramide (LacCer) production and ERK1/2 activation following ERC Neu-1 subunit activation. The ability for ERC to transduce signals is lost during aging, but the mechanism involved is still unknown. In this study, we characterized an in vitro model of aging by subculturing human dermal fibroblasts. This model was used to understand the loss of EDP biological activities during aging. Our results show that ERC uncoupling does not rely on Neu-1 or PPCA mRNA or protein level changes. Furthermore, we observe that the membrane targeting of these subunits is not affected with aging. However, we evidence that Neu-1 activity and LacCer production are altered. Basal Neu-1 catalytic activity is strongly increased in aged cells. Consequently, EDP fail to promote Neu-1 catalytic activity and LacCer production in these cells. In conclusion, we propose, for the first time, an explanation for ERC uncoupling based on the age-related alterations of Neu-1 activity and LacCer production that may explain the loss of EDP-mediated effects occurring during aging

Action of Mangifera indica Leaf Extract on Acne-Prone Skin through Sebum Harmonization and Targeting C. acnes

(1) Background: Preclinical studies report that the ethanolic fraction from Mangifera&nbsp;indica leaves is a potential anti-acne agent. Nevertheless, the biological activity of Mangifera indica leaves has scarcely been investigated, and additional data are needed, especially in a clinical setting, for establishing the actual effectiveness of Mangifera indica extract as an active component of anti-acne therapy. (2) Methods: The evaluation of the biological activity of Mangifera indica extract was carried out through different experimental phases, which comprised in silico, in vitro, ex vivo and clinical evaluations. (3) Results: In silico and in vitro studies allowed us to identify the phytomarkers carrying the activity of seboregulation and acne management. Results showed that Mangifera indica extract reduced lipid production by 40% in sebocytes, and an improvement of the sebum quality was reported after the treatment in analyses performed on sebaceous glands from skin explants. The evaluation of the sebum quantity and quality using triglyceride/free fatty acid analysis conducted on Caucasian volunteers evidenced a strong improvement and a reduction of porphyrins expression. The C. acnes lipase activity from a severe acne phylotype was evaluated in the presence of Mangifera indica, and a reduction by 29% was reported. In addition, the analysis of the skin microbiota documented that Mangifera indica protected the microbiota equilibrium while the placebo induced dysbiosis. (4) Conclusions: Our results showed that Mangifera indica is microbiota friendly and efficient against lipase activity of C. acnes and supports a role for Mangifera indica in the therapeutic strategy for prevention and treatment of acne

Interaction between the elastin peptide VGVAPG and human elastin binding protein.

International audienceThe elastin binding protein (EBP), a spliced variant of lysosomal β-galactosidase, is the primary receptor of elastin peptides that have been linked to emphysema, aneurysm and cancer progression. The sequences recognized by EBP share the XGXXPG consensus pattern found in numerous matrix proteins, notably in elastin where the VGVAPG motif is repeated. To delineate the elastin binding site of human EBP, we built a homology model of this protein and docked VGVAPG on its surface. Analysis of this model suggested that Gln-97 and Asp-98 were required for interaction with VGVAPG because they contribute to the definition of a pocket thought to represent the elastin binding site of EBP. Additionally, we proposed that Leu-103, Arg-107, and Glu-137 were essential residues because they could interact with VGVAPG itself. Site-directed mutagenesis experiments at these key positions validated our model. This work therefore provides the first structural data concerning the interaction of the VGVAPG with its cognate receptor. The present structural data should now allow the development of EBP-specific antagonists