Acacetin resists UVA photoaging by mediating the SIRT3/ROS/MAPKs pathway

Area of Science:

• Dermatology
• Biochemistry
• Molecular Biology

Background:

• Ultraviolet A (UVA) radiation significantly contributes to skin photoaging.
• Understanding molecular mechanisms underlying UVA-induced skin damage is crucial for developing effective interventions.

Purpose of the Study:

• To investigate the protective effects of Acacetin against UVA-induced skin photoaging.
• To elucidate the role of SIRT3 in Acacetin's photoprotective mechanisms.

Main Methods:

• UVA irradiation was applied to mice and human dermal fibroblasts (HDF).
• Acacetin was administered topically to mice and to HDF cultures prior to UVA exposure.
• Key molecular markers including SIRT3, MAPKs, MMPs, TGF-β, and Smad3 were analyzed.
• The SIRT3 inhibitor 3-TYP was used to confirm the dependency of Acacetin's effects.

Main Results:

• Acacetin ameliorated UVA-induced oxidative stress and cell death in both mice and HDF.
• Acacetin prevented UVA-induced decrease in SIRT3 expression.
• Acacetin inhibited the activation of MAPKs (p-38, p-JNK) and reduced MMPs.
• Acacetin increased collagen-promoting proteins (TGF-β, Smad3) and its protective effects were SIRT3-dependent.

Conclusions:

• Acacetin demonstrates significant photoprotective effects against UVA radiation.
• The mechanism involves the upregulation of SIRT3, leading to reduced oxidative stress, inflammation, and enhanced collagen synthesis.
• Acacetin is a promising therapeutic agent for mitigating skin photoaging.