Ultraviolet-A triggers photoaging in model nematode Caenorhabditis elegans in a DAF-16 dependent pathway.

Ultraviolet radiations (UV) are the primary causative agent for skin aging (photoaging) and cancer, especially UV-A. The mode of action and the molecular mechanism behind the damages caused by UV-A is not well studied, in vivo. The current study was employed to investigate the impact of UV-A exposure using the model organism, Caenorhabditis elegans. Analysis of lifespan, healthspan, and other cognitive behaviors were done which was supported by the molecular mechanism. UV-A exposure on collagen damages the synthesis and functioning which has been monitored kinetically using engineered strain, col-19:: GFP. The study results suggested that UV-A accelerated the aging process in an insulin-like signaling pathway dependent manner. Mutant (daf-2)-based analysis concrete the observations of the current study. The UV-A exposure affected the usual behavior of the worms like pharyngeal movements and brood size. Quantitative PCR profile of the candidate genes during UV-A exposure suggested that continuous exposure has damaged the neural network of the worms, but the mitochondrial signaling and dietary restriction pathway remain unaffected. Western blot analysis of HSF-1 evidenced the alteration in protein homeostasis in UV-A exposed worms. Outcome of the current study supports our view that C. elegans can be used as a model to study photoaging, and the mode of action of UV-A-mediated damages can be elucidated which will pave the way for drug developments against photoaging.