Silva, Michelle Sabrina1; Facchini, Gustavo1; Buzalaf, Marilia Afonso Rabelo2, Leite, Aline Lima2, Eberlin, Samir3; Pinheiro, Ana Lucia Tabarini Alves1, Pinheiro, Adriano da Silva, Eberlin, Samara1.
Hair is an important and evolutionarily conserved structure. It originates from hair follicles deep within the dermis and is mainly composed of hair keratins and KAPs (Keratin-Associated Proteins), which form a complex network that contributes to the rigidity and mechanical properties. Hair damage is a multifactorial process influenced by genetic and environmental factors. A classic example of an environmental factor is ultraviolet (UV) radiation, which results in the induction of oxidative stress and the production of free radicals capable of causing damage to structures present in the hair follicle (HF) and hair fiber. However, the mechanisms associated with hair photodamage are still not completely clear. In this study we investigate the effects of UVA/B radiation in human scalp with the purpose of developing novel biomarkers for healthy and damaged hair using proteomic analysis. Scalp fragments from healthy female subjects, aged 40-60 years, submitted to rhytidoplasty, were fractionated using a punch nº 5 and cultured overnight. After this period, they were exposed to daily doses of 10 J/cm2 UVA/B radiation for five consecutive days, using UVA Cube 400, SOL 500 H2 filter and UV Meter. After 24 hours of the last dose of UVA/B, scalp fragments were collected. Total protein were extracted and analyzed by high-resolution label-free mass spectrometry (MSE) approach to identify differential protein expression. The results were analyzed by ProteinLynx Global Server (PLGS) and Cytoscape combined with Cluster Marker and ClueGO plugins were used to perform bioinformatic analysis. Proteomic analysis is a tool capable to identify and quantify the proteome of a biological system. The results obtained for proteomic analysis between control and UVA/B groups revealed alterations of several proteins correlated with important biological processes associated with hair growth, development, loss and pigmentation. We observed that UVA/B radiation, at the experimental dose proposed in this study, significantly altered proteins associated with cell cycle, cornified envelope formation, telomere maintenance, WNT signaling, cell response to stress, oxidative stress induced senescence and cellular response to stimuli external. In this study, we used proteomics platform to analyze the effects of UVA/B radiation on the hair, allowing an overview of the damage in fiber and hair follicle. Oxidative stress induced by UV radiation impacts directly the dermal papilla cells from HF, inducing the senescence status and suppresses follicular differentiation of keratinocytes, which accelerates the hair follicle loss. Furthermore, oxidative stress compromises the niche of melanocytes in HF, leading to changes in melanogenic pathways and cell death, culminating in hair depigmentation. Additionally we observed an important alteration in histones and intermediate keratin filaments that compromise the structure of hair fiber, impairing strength and mechanical resistance. Taken together our results of proteomic analysis demonstrated a compromising of proteins associated with basic mechanisms of hair development suggesting a direct impact of UVA/B radiation on hair growth, loss, pigmentation, thinning and morphology. This results in sustained new markers for evaluating the effectiveness of dermocosmetics for hair treatment.