Omega-7 inhibits inflammation and promotes collagen synthesis through SIRT1 activation

Excessive accumulation of reactive oxygen species (ROS) during oxidative stress accelerates the skin aging process. ROS stimulate inflammatory processes in the skin, leading to activation of matrix metalloprotease-1 (MMP-1). Silent information regulator 1 (SIRT1) controls a broad range of cellular functions including the expression of MMP-1. Omega-7 fatty acids such as palmitoleic acid have many beneficial effects on health, including improvement in cardiovascular risk factors and increased insulin sensitivity. However, the effectiveness of omega-7 fatty acids (herein referred to as omega-7) related to skin aging, characterized by the degradation of collagen and loss of elasticity, remains unclear. We here investigated the effects of palmitoleic acid, a representative omega-7, on collagen regeneration through its ability to activate SIRT1 and inhibit MMP-1 in the presence of hydrogen peroxide (H₂O₂)-induced oxidative stress in human HaCaT cells. SIRT1 activation by omega-7 decreased signaling levels of nuclear transcription factor kappa B (NF-κB) and inflammatory cytokines. However, inhibition of SIRT1 by sirtinol counteracted the advantage effects of omega-7 in H₂O₂-treated HaCaT cells. In addition, omega-7 significantly counteracted the decrease in collagen abundance and loss of elasticity induced by H₂O₂. Consistent with this observation, omega-7 significantly decreased H₂O₂-induced upregulation of MMP-1 in HaCaT cells. Together, these studies suggest the potential efficacy of SIRT1 in collagen regeneration and indicate that omega-7 is a possible functional food to improve skin health for the prevention of aging.