Abstract
OBJECTIVE: Oxidative stress and its induced protein alterations are instrumental in the early onset and progression of ageing. To protect the skin proteome, we evaluated the extract of a bacterium isolated from snowflakes (Arthrobacter agilis). This Arthrobacter agilis extract (AAE) has been found to be rich in bacterioruberins, C-50 unsaturated carotenoids with potent antioxidative properties. METHODS: The Arthrobacter agilis extract (AAE), having protective effect against oxidative, saline, and heat stresses, was evaluated in tubo. Protection against protein carbonylation was assessed in human primary keratinocytes and skin explants subjected to various stresses. The impact of an AAE-containing cream on protein carbonylation was analysed on the face of 23 smokers after 28 days. RESULTS: In tubo, AAE protects alkaline phosphatase against oxidative and heat stresses, increasing the temperature at which BSA is denatured. It also partially prevented elastin aggregation induced by a salt stress. In human primary keratinocytes exposed to UV, particulate matter (PM), or blue light, AAE reduced protein carbonylation, a marker of oxidative stress in the proteome. When formulated in creams, topical applications prevent protein carbonylation in the epidermis and dermis of skin explants co-exposed to UV and PM. Furthermore, after 28 days of application, protein carbonylation was reduced in the upper skin layers of smokers. CONCLUSIONS: AAE protects the proteome against oxidative stress via a dual mode of action: antioxidant and chaperone-like activities (as demonstrated by protection against heat and salt). AAE is a promising age-management compound that safeguards the fragile skin ecosystem in an ecobiological approach, protecting the effectors of healthy skin functioning and reinforcing natural defences when overwhelmed.