MiR-23a-depressed autophagy is a participant in PUVA- and UVB-induced premature senescence

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Autophagy is a key cellular process involved in stress response and linked to aging and cancer.
• MicroRNAs (miRNAs) are emerging as critical regulators of autophagy.
• The specific role of miR-23a in photoaging remains largely unexplored.

Purpose of the Study:

• To investigate the role of autophagy-related microRNA miR-23a in the process of photoaging.
• To identify the molecular targets and mechanisms through which miR-23a influences UV-induced cellular damage.

Main Methods:

• Utilized antagomirs to inactivate miR-23a in human fibroblasts.
• Assessed autophagy flux following PUVA and UVB irradiation.
• Identified and validated AMBRA1 as a direct target of miR-23a using bioinformatics and experimental approaches.
• Investigated the effects of AMBRA1 overexpression and miR-23a modulation on fibroblast protection from UV-induced damage.

Main Results:

• Inactivation of miR-23a stimulated autophagy flux suppressed by PUVA and UVB radiation.
• miR-23a inactivation protected human fibroblasts from premature senescence.
• AMBRA1 was identified as a direct target of miR-23a, with its levels increasing upon miR-23a inhibition.
• AMBRA1 overexpression and Rapamycin treatment rescued fibroblasts from UV-induced autophagy inhibition, but these effects were diminished by miR-23a overexpression.

Conclusions:

• miR-23a acts as a significant regulator of autophagy in the context of ultraviolet-induced premature senescence.
• AMBRA1 is a critical, rate-limiting miRNA target within the miR-23a-mediated pathway controlling photoaging.