Longevity and circadian rhythm in Caenorhabditis elegans: the impact of lithium chloride

Abstract

Lithium chloride (LiCl) is a popular treatment for various neurological disorders, especially bipolar disorders. While its complete mechanism of action remains partially elucidated, LiCl has been found to support new memory formation by triggering the construction of new neurons, reducing senescence, and regulating the circadian rhythm, particularly in bipolar patients, where it counteracts their abnormally fast biological clock. The circadian rhythm is vital in determining efficiency, understanding energy consumption, and biochemical balance for all organisms. This rhythm includes regulating body functions by the day/night cycle. Caenorhabditis elegans (C. elegans) is one of the most robust organisms for modeling circadian rhythm, although it lives in the soil. Therefore, by employing C. elegans as a model system, valuable insights could be gained for these complex processes. This study aims to elucidate the complex relationship between LiCl, circadian rhythms, and longevity, as disruptions in these pathways are implicated in neurodegenerative diseases and age-related cognitive and motor decline. In this project, white light was employed to manipulate the circadian rhythm in C. elegans, with one group additionally receiving LiCl treatment in addition to light exposure. The study focused on longevity, response to environmental factors, and circadian rhythm. To elucidate the effect on longevity, lifespan measurements showed that LiCl treatment extended the lifespan of C. elegans under both light and dark conditions, with a shorter lifespan observed in the light. Additionally, when comparing the effect of specific developmental time points, the signs of aging appeared later in the dark compared to the light. The differential gene expression of longevity genes suggested that LiCl treatment could impact gene expression, particularly the age-1 gene, but not the daf-16 gene. Furthermore, the response to environmental changes was examined imilarly and it was observed that C. elegans responded to the circadian rhythm disruption caused by light and LiCl administration. In conclusion, this study suggests that LiCl treatment has the potential to mitigate the adverse effects of circadian rhythm disruptions and reverse the aging process of C. elegans.