Correlation between Proteasome Activity and ECM Component Synthesis and Improvement Effect on Skin Elasticity by Adzuki Bean Extract

Abstract

The proteasome is a large multi-protein complex that plays a central role in protein degradation. Proteasome activity decreases with age, and proteasome inhibition results in increased production of Matrix metalloproteinases (MMPs) and decreased collagen synthesis in fibroblasts. Although proteasome may play an important role in maintaining Extracellular Matrix (ECM) components, there have been few studies investigating the correlation between proteasome activity and synthesis of ECM components other than collagen. To elucidate new mechanisms of sagging on the face with age, we focused on the correlation between proteasome activity and ECM component synthesis. It was revealed that inhibition of proteasome activity reduced gene expression of collagen, hyaluronan synthase and elastin in fibroblasts. This result suggests that proteasome plays an important role in maintaining ECM components. Therefore, a decline of proteasome activity may lead to increased wrinkles and sagging with age. Furthermore, we found that adzuki bean extract had an effect that improved the elasticity of the skin by activating proteasome. Adzuki bean extract effectively increased proteasome activity, collagen synthesis and gene expression of hyaluronan synthase and elastin in fibroblasts. Moreover, it improved the elasticity and tactile elasticity of the face in vivo. Together, the findings suggest that adzuki bean extract increases ECM component synthesis by increasing proteasome activity and that this effect appears even in vivo.