Abstract
The lymphatic system plays an important role in the maintenance of tissue fluid homeostasis and the afferent phase of immune response. However, the role of the lymphatic system in mediation of aging and its molecular mechanism have been totally unknown. Here we have identified, for the first time, the importance of the cutaneous lymphatic system in the process of ultraviolet (UV) B-induced skin-damage. UVB induced the prominent enlargement of lymphatic vessels which were leaky and hyperpermeable, suggesting that the function of enlarged lymphatic vessels induced by UVB was impaired. Moreover, impaired lymphatic function could cause prolonged inflammation with retained macrophages in the dermis, eventually leading to wrinkle formation. A potent lymphangiogenesis factor, VEGFC was downregulated after UVB irradiation in vitro as well as in vivo, suggesting that the impairment of lymphatic function was triggered by VEGFC downregulation. MACC, which was found to be a novel VEGFC-inducing compound in keratinocytes, has a strong potential to prevent UVB-induced skin damage/wrinkle formation by promoting lymphatic vessel growth and function.
