A new matrikine-derived peptide up-regulates longevity genes for improving extracellular matrix architecture and connections of dermal cell with its matrix.

OBJECTIVE: Skin extracellular matrix (ECM) is a dense and well-organized structure produced by fibroblasts. This ECM transduces environmental mechano-signals to cell nucleus through the integrin-actin complex, thus triggering ECM protein syntheses. The aim of this study was to discover a novel peptide, structurally related to dermal matrikines, that promotes syntheses of ECM components. METHODS AND RESULTS: Screening tests with 120 peptides were carried out by using normal dermal human fibroblasts (HF). As a result, one candidate of interest was isolated, the N-Prolyl Palmitoyl Tripeptide-56 Acetate (PP56), which increases collagen and fibronectin productions at gene and/or protein levels. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), a recent and innovative analytical technology, in addition to more traditional techniques, it was showed that two metabolic pathways were significantly modulated: one for collagen production and one for actin. Moreover, this peptide up-regulated the transcription of Forkhead Box O (FOXO) and sestrin messenger RNAs (mRNA), leading to production of proteins involved into longevity and more recently in collagen production. RESULTS: Results indicated that this peptide is a potential candidate to improve ECM density and organization in a new way.

OBJECTIF: La matrice extracellulaire cutanée (MEC) est une structure dense et bien organisée produite par les fibroblastes. Cette MEC transduit les mécano-signaux environnementaux vers le noyau de la cellule par le biais du complexe intégrine-actine, ce qui déclenche la synthèse de protéines par la MEC. Le but de cette étude était de découvrir un nouveau peptide, structurellement apparenté aux matrikines dermiques, qui favorise la synthèse des composants de la MEC. MÉTHODES ET RÉSULTATS: Des tests de criblage avec 120 peptides ont été réalisés en utilisant des fibroblastes humains dermaux normaux (HF). Un candidat d'intérêt a été isolé, l'acétate de N-Prolyl Palmitoyl-Tripeptide-56 (PP56), qui augmente les productions de collagène et de fibronectine aux niveaux du gène et / ou de la protéine. En utilisant une technologie analytique récente et innovante, la spectrométrie de masse par chromatographie liquide-tandem (LC-MS / MS) ainsi que des techniques plus traditionnelles, il a été démontré que deux voies métaboliques sont modulées de manière significative: une pour la production de collagène et une pour l'actine. En outre, ce peptide a régulé positivement la transcription des ARN messagers (ARNm), du facteur de transcription Forkhead Box (FOXO) et de la sestrine, conduisant à la production de protéines impliquées dans la longévité et plus récemment dans la production de collagène. RÉSULTATS: Les résultats ont indiqué que ce peptide est un candidat potentiel pour améliorer la densité et l'organisation de la MEC d'une manière nouvelle.

Reinforcement of barrier function and scalp homeostasis by Senkyunolide A to fight against dandruff.

OBJECTIVE: Senkyunolide-A (SENKY) can be isolated from Apium graveolens seed oil obtained using supercritical CO2 extraction. SENKY and its parent compounds, the N-butyl phthalides, have been demonstrated to protect cells from CO poisoning, to prevent diabetes mellitus and to decrease cancer cell proliferation. This study was undertaken to evaluate in vitro and in vivo the effect of SENKY on epidermal function improvement, Malassezia effect control, scalp soothing and dandruff reduction via skin protection-related pathways. METHODS: DNA-array and proteomic studies were performed on human keratinocytes, sebocytes and skin explants to demonstrate SENKY activities. Two clinical evaluations were performed under dermatologist control on 106 volunteers, with greasy or dry scalp, experiencing dandruff, itching and redness. Volunteers tested a shampoo followed, or not, by a leave-on, containing SENKY, or their placebos. Dandruff severity and redness were scored on the scalp. Moisturization and sebum release were recorded using relevant measuring apparatus. Itching and scratching evaluations came from volunteers' self-declarations. RESULTS: DNA-array studies on keratinocytes showed a clear regulation of skin barrier functions and epidermis defence pathways. Upregulation of epidermal differentiation complex genes was observed. These preliminary observations were reinforced by immunocytochemistry and immunohistochemistry studies showing a significant increase of involucrin, filaggrin, loricrin, SPRR, LC3B and ceramide 2 productions. Tight-junctions and corneodesmosomes were significantly reinforced both in keratinocyte cultures (corneodesmosin, claudin, ZO-1) and in skin explants (desmoglein). DNA-array studies also demonstrated upregulation of genes involved in detoxification and anti-inflammation pathways. Proteomic studies revealed that hBD2 production was increased in keratinocytes in contact with SENKY, whereas IL-8, PGE-2 and TLR-9 releases were repressed as well as sebocyte lipid production. Clinical evaluations confirmed that after 3 weeks, SENKY significantly reduced dandruff intensity, redness, itching and scalp histamine content compared to placebo and beginning of treatment. CONCLUSION: For the first time, SENKY has been shown to promote scalp homoeostasis by reinforcing barrier and defence functions at both gene and protein levels. It reduces irritation and redness in promoting detoxification and anti-inflammation pathways while controlling the niche of Malassezia. Applied on scalp, SENKY significantly reduces the formation of dandruff and soothes the scalp.

Whole-exome sequencing improves the diagnosis yield in sporadic infantile spasm syndrome.

Infantile spasms syndrome (ISs) is characterized by clinical spasms with ictal electrodecrement, usually occurring before the age of 1 year and frequently associated with cognitive impairment. Etiology is widely heterogeneous, the cause remaining elusive in 40% of patients. We searched for de novo mutations in 10 probands with ISs and their parents using whole-exome sequencing (WES). Patients had neither consanguinity nor family history of epilepsy. Common causes of ISs were excluded by brain magnetic resonance imaging (MRI), metabolic screening, array-comparative genomic hybridization (CGH) and testing for mutations in CDKL5, STXBP1, and for ARX duplications. We found a probably pathogenic mutation in four patients. Missense mutations in SCN2A (p.Leu1342Pro) and KCNQ2 (p.Ala306Thr) were found in two patients with no history of epilepsy before the onset of ISs. The p.Asn107Ser missense mutation of ALG13 had been previously reported in four females with ISs. The fourth mutation was an in-frame deletion (p.Phe110del) in NR2F1, a gene whose mutations cause intellectual disability, epilepsy, and optic atrophy. In addition, we found a possibly pathogenic variant in KIF3C that encodes a kinesin expressed during neural development. Our results confirm that WES improves significantly the diagnosis yield in patients with sporadic ISs.