Tetramethylpyrazine Nitrone Delays the Aging Process of C. Elegans by Improving Mitochondrial Function Through the AMPK/mTORC1 Signaling Pathway

Aging is characterized as the process of functional decline in an organism from adulthood, often marked by a progressive loss of cellular function and systemic deterioration of multiple tissues. Among the numerous molecular, cellular, and systemic hallmarks associated with aging, mitochondrial dysfunction is considered one of the pivotal factors that initiates the aging process. During aging, mitochondria undergo varying degrees of damage, resulting in impaired energy production and disruption of the homeostatic regulation of mitochondrial quality control systems, which in turn affects cellular energy metabolism and results in cellular dysfunction, accelerating the aging process. AMP-activated protein kinase (AMPK) and the mechanistic target of rapamycin complex 1 (mTORC1) are two central kinase complexes responsible for sensing intracellular nutrient levels, regulating metabolic homeostasis, modulating aging and play a crucial role in maintaining the homeostatic balance of mitochondria. Our previous studies found that the novel compound tetramethylpyrazine nitrone (TBN) can protect mitochondria via the AMPK/mTOR pathway in many animal models, extending healthy lifespan through the Nrf2 signaling pathway in nematodes. Building upon this foundation, we have posited a reasonable hypothesis, TBN can improve mitochondrial function to delay aging by regulating the AMPK/mTORC1 signaling pathway. This study focuses on the C. elegans, exploring the impact and underlying mechanisms of TBN on aging and mitochondrial function (especially the mitochondrial quality control system) during the aging process. The present studies demonstrated that TBN extends lifespan of wild-type nematodes and is associated with the AMPK/mTORC1 signaling pathway. TBN elevated ATP and NAD+ levels in aging nematodes while orchestrating mitochondrial biogenesis and mitophagy. Moreover, TBN was observed to significantly enhance normal activities during aging in C. elegans, such as mobility and pharyngeal pumping, concurrently impeding lipofuscin accumulation that were closely associated with AMPK and mTORC1. This study not only highlights the delayed effects of TBN on aging but also underscores its potential application in strategies aimed at improving mitochondrial function via the AMPK/mTOR pathway in C. elegans.