373 Effect of Haritaki fruit extract on Senescence Associated Secretory Phenotype and miR 30a-3p over-expression in senescent dermal fibroblasts’ extracellular vesicles

Abstract

Skin aging is the consequence of two biological process: intrinsic genetically programmed factors and extrinsic environmental factors (sun exposure or lifestyle). At the cellular level, accumulation of senescent cells (SC) is also involved in skin aging. SC stop to proliferate but remain metabolically active. The secretome of SC (Senescence Associated Secretory Phenotype: SASP), is a cocktail of mediators (CSF3, CXCL1, IL8, IL1b, IL6, MMP-1 and -3) involved in skin aging. Extracellular vesicles (EV) have also been reported to act in a similar manner as cytokines during intercellular communication. They transport proteins, mRNAs and miRNAs, over short or long distances. miRNAs are a class of short, single-stranded, noncoding RNA molecules. By binding the specific 3’-UTRs sequence of the target mRNAs, they regulate the expression of multiple genes at the post-transcriptional level through degradation. For instance, miR 30a has been described as a key regulator of aging in human epidermis by regulating barrier function and keratinocytes apoptosis in human epidermis. The aim of our study was to evaluate, by RT-PCR, the effect of Haritaki fruit extract (HF extract) on SASP and senescence associated miR 30a-3p contained in EV. Our results showed that, 14 days after ionizing radiation (7.5 Gy), human dermal fibroblasts presented a senescent phenotype: flattened and irregular shape, senescence associated b-galactosidase activity, SASP over-expression (RT-PCR) and mir 30a-3p overexpression in EV (RT-PCR). Our results also showed that incubation of senescent fibroblasts with HF extract strongly decreased SASP mRNA level and miR 30a-3p expression in EV. Taken together these results demonstrated that Haritaki fruit extract is a strong senomorphic agent, suggesting that it may be useful for the development of new anti- aging dermo-cosmetic products.