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To explore synergistic effects related to skin regeneration, peptides with distinct biological mechanisms of action were evaluated in combination with different skin cell lines in the presence or absence of niacinamide (Nam). Furthermore, the synergistic responses of peptide combinations on global gene expression were compared with the changes that occur with fractional laser resurfacing treatment, a gold standard approach for skin rejuvenation, to further define optimal peptide combinations.Microarray profiling was used to characterize the biological responses of peptide combinations (+/- Nam) relative to the individual components in epidermal keratinocyte and dermal fibroblast cell lines. Cellular functional assays were utilized to confirm the synergistic effects of peptide combinations. Bioinformatics approaches were used to link the synergistic effects of peptide combinations on gene expression to the transcriptomics of the skin rejuvenation response from fractional laser treatment.Microarray analysis of skin cells treated with peptide combinations revealed synergistic changes in gene expression compared with individual peptide controls. Bioinformatic analysis of synergy genes in keratinocytes revealed the activation of NRF2-mediated oxidative stress responses by a combination of Ac-PPYL, Pal-KTTKS and Nam. Additional analysis revealed direct downstream transcriptional targets of NRF2/ARE exhibiting synergistic regulation by this combination of materials, which was corroborated by a cellular reporter assay. NRF2-mediated oxidative stress response pathways were also found to be activated in the transcriptomics of the early skin rejuvenation response to fractional laser treatment, suggesting the importance of this biology in the early stages of tissue repair. Additionally, the second combination of peptides (pal-KT and Ac-PPYL) was found to synergistically restore cellular ATP levels that had been depleted due to the presence of ROS, indicating an additional mechanism, whereby peptide synergies may accelerate skin repair.Through combinatorial synergy studies, we have identified additional in vitro skin repair mechanisms beyond the previously described functions of individual peptides and correlated these to the transcriptomics of the skin rejuvenation response of fractional laser treatment. These findings suggest that specific peptides can act together, via complementary and synergistic mechanisms, to holistically enhance the regenerative capacity of in vitro skin cells.Pour explorer les effets synergiques liés à la régénération cutanée, les peptides ayant des mécanismes d’action biologiques distincts ont été évalués en association dans différentes lignées cellulaires cutanées en présence ou en l’absence de niacinamide (Nam). De plus, les réponses synergiques des associations de peptides sur l’expression des gènes globale ont été comparées aux changements qui surviennent avec le traitement de resurfaçage au laser fractionné, une approche de référence pour le rajeunissement de la peau, afin de définir davantage les associations optimales de peptides. MÉTHODES: Le profilage de micro-réseau a été utilisé pour caractériser les réponses biologiques des combinaisons de peptides (+/-Nam) par rapport aux composants individuels dans les lignées cellulaires de kératinocytes épidermiques et de fibroblastes dermiques. Des tests fonctionnels cellulaires ont été réalisés pour confirmer les effets synergiques des associations de peptides. Des approches bio-informatiques ont été utilisées pour mettre en lien les effets synergiques des associations de peptides sur l’expression des gènes à la transcriptomique de la réponse de rajeunissement de la peau du traitement au laser fractionné. RÉSULTATS: L’analyse par micro-réseau des cellules cutanées traitées par des combinaisons de peptides a révélé des changements synergiques dans l’expression des gènes par rapport aux contrôles peptidiques individuels. L’analyse bio-informatique des gènes de synergie dans les kératinocytes a révélé une activation des réponses au stress oxydatif médiées par NRF2 par une association d’Ac-PPYL, de Pal-KTTKS et de Nam. Une analyse supplémentaire a révélé des cibles transcriptionnelles directes en aval de NRF2/ARE présentant une régulation synergique par cette combinaison de matériaux, qui a été corroborée par un test de gène rapporteur. Les voies de réponses au stress oxydatif médiées par NRF2 se sont également révélées activées dans la transcriptomique de la réponse précoce de rajeunissement cutané au traitement au laser fractionné, ce qui suggère l’importance de cette biologie dans les stades précoces de la réparation des tissus. De plus, une deuxième association de peptides (pal-KT et Ac-PPYL) s’est avérée restaurer de manière synergique les taux d’ATP cellulaire qui avaient été épuisés en raison de la présence de ROS, indiquant un mécanisme supplémentaire par lequel les synergies de peptides pourraient accélérer la réparation cutanée.Grâce à des études de synergie combinatoire, nous avons identifié des mécanismes de réparation cutanés in vitro supplémentaires au-delà des fonctions précédemment décrites des peptides individuels et les avons corrélés à la transcriptomique de la réponse de rajeunissement de la peau au traitement au laser fractionné. Ces résultats suggèrent que des peptides spécifiques peuvent agir ensemble, par le biais de mécanismes complémentaires et synergiques, pour améliorer de manière globale la capacité régénérative des cellules cutanées in vitro.

Background Intrinsic and extrinsic factors, including ultraviolet irradiation, lead to visible signs of skin aging. Objective We evaluated molecular changes occurring in photoexposed and photoprotected skin of white women 20 to 74 years of age, some of whom appeared substantially younger than their chronologic age. Methods Histologic and transcriptomics profiling were conducted on skin biopsy samples of photoexposed (face and dorsal forearm) or photoprotected (buttocks) body sites from 158 women. 23andMe genotyping determined genetic ancestry. Results Gene expression and ontologic analysis revealed progressive changes from the 20s to the 70s in pathways related to oxidative stress, energy metabolism, senescence, and epidermal barrier; these changes were accelerated in the 60s and 70s. The gene expression patterns from the subset of women who were younger-appearing were similar to those in women who were actually younger. Limitations Broader application of these findings (eg, across races and Fitzpatrick skin types) will require further studies. Conclusions This study demonstrates a wide range of molecular processes in skin affected by aging, providing relevant targets for improving the condition of aging skin at different life stages and defining a molecular pattern of epidermal gene expression in women who appear younger than their chronologic age.

In human skin fibroblasts in vitro, procollagen-1 and NAD(+)/NADH were reduced in three strains of adult fibroblasts compared with neonatal fibroblasts. The levels of both procollagen-1 and NAD(+)/NADH were increased in the adult fibroblasts by treatment for 24 (NAD energy) or 48 h (procollagen-1) with a complex containing niacinamide, Pal-KTTKS peptide and an olive oil fatty acid derivative (Olivem(®)), especially in combination with a natural extract from dill (Lys'lastine V(®)). In one of the adult fibroblast strains evaluated, these changes in procollagen-1 and NAD(+)/NADH in response to the complex of bioactives were in parallel with increased expression of mRNA biomarkers related primarily to dermal matrix and basement membrane structure, including COL1A1, COL3A1, COL5A1, COL14A1, ELN and LOXL2, in addition to SOD2, NAMPT and TGFBR3; MMP1 was decreased in expression. In general, these mRNA biomarker effects were maintained or boosted by the addition of Lys'lastine V, particularly at 1%, and were similar to the fold changes in mRNA expression in neonatal compared with adult fibroblasts. These results indicate that the complex of niacinamide, Pal-KTTKS and Olivem, especially with addition of Lys'lastine V, increases the NAD(+)/NADH bioenergy level of adult skin fibroblasts in parallel with increased expression of skin structure biomarkers in vitro to levels similar to those in younger fibroblasts. Thus, niacinamide, Pal-KTTKS, Olivem and Lys'lastine V are promising bioactive candidates for inclusion in cosmetic formulations.

The field of tissue engineering is multidisciplinary, seeking to fabricate artificial organs or substitutes in order to replace failing or damaged organs. These engineered tissues and organs are mostly targeted as substitutes for human donor tissues and as such are developed to avoid the complications associated with donor matching and immune rejection [1]. Examples include substitutes of organs including liver, heart, kidney, skin, teeth, and cornea [2].