Skin proteome protection, a new ecobiological target in healthy aging

• Deinococcus radiodurans bacteria are a model to study longevity as they can survive in extreme environmental conditions. Their analysis led to a new scientific paradigm: protection of the proteome is the key to cellular longevity. Indeed, their DNA is altered but repaired by ultra resistant proteins protected by molecules with chaperone like and antioxidant activities. In skin, among the most harmful damages, carbonylation an irreversible alteration specific to proteins, generates toxic aggregates for the cells, leading to premature aging.
• The aim of this study was to evaluate the efficacy of bacterioruberins a new class of chaperone like and antioxidant molecules extracted from another extremophilic bacteria, Arthrobacter agilis, on proteome protection and consecutive prevention of all skin aging signs.

• First, we assessed in tubo bacterioruberins on the physical protection via chaperone like effect using both the Bovine Serum Albumin (BSA) protein test with HPLC analysis (to assess protein binding capacity) and the Alkaline Phosphatase (AP) heat test at 55°C, and on the biological protection via antioxidant properties using ABTS test All tests assessed reference molecules
• Second, evaluation of carbonylated protein level was performed:

- in vitro on normal human keratinocytes exposed to UVA (365 nm, 28 J/cm²), fine particles (PM 10 50 μg/mL) or blue light (460 nm, 72 J/cm²) using a specific fluorescent probe targe ti ng carbonyls products

- in vivo during a 28 day clinical study on 23 smoking women (38 to 69 years old), phototypes II to III with a dull complexion, applying on hemi face twice daily a serum containing bacterioruberins versus placebo A carbonylation score was assessed by measuring the total proteins (Bradford methods) and the carbonylated protein (specific fluorescent probe) on protein extracted from D-Squam samples performed on the hemi-faces

• Finally, a clinical study was performed on 55 women (42 to 65 years old) who applied for 6 months twice daily on half-face a neutral cream and a serum containing bacterioruberins vs the neutral cream alone. Each month, the main aging signs were scored (wrinkles [crow's feet, under eye and nasolabial fold] firmness, density, complexion, pigment spots and radiance) from which a global aging evolution was calculated, and pictures were taken

Proteome protection is key for cellular longevity. Thanks to the chaperone-like and antioxidant properties of bacterioruberins contained in a serum, the latter induces visibly higher and faster improvements of all aging signs.