生物钟是生物体内的一种内在节律调控系统，能够调节和协调身体的众多生理功能，如行为学、新陈代谢、体温调节和激素分泌等。这种内在机制对有机体的适应和生存至关重要，使其能够适应日常环境变化并优化生理功能和行为模式。然而，随着年龄的增长，生物钟的调控能力逐渐下降。这种退化不仅影响个体的生活质量，还加速衰老过程，并增加了心血管疾病、代谢综合征和神经退行性疾病等慢性疾病的风险。此外，肥胖也会对全身器官的功能产生负面影响。尽管越来越多的研究表明，增强生物钟功能可能在一定程度上减缓这些疾病的进展，但尚缺乏针对性的策略来恢复昼夜节律，以减缓与肥胖和衰老相关的疾病，并延长寿命。因此，探索恢复昼夜节律以促进老龄动物健康长寿及抵抗代谢性疾病的机制迫在眉睫。

本研究利用实验室筛选出的具有调节生物钟的小分子化合物3’-脱氧腺苷，以评估其在促进老龄鼠健康长寿及预防代谢紊乱相关疾病方面的潜力。观察了该化合物对高脂饮食诱导的肥胖小鼠模型和老龄鼠自主活动和能量消耗的昼夜节律、行为学、细胞衰老标志物的影响，并通过转录组学分析、表观遗传学分析、全脑免疫荧光c-FOS+ mapping、化学遗传学和光遗传学等方法探讨其具体作用和机制。

研究结果表明，3’-脱氧腺苷增强了肥胖小鼠和老龄鼠自主活动量、内分泌激素的合成与分泌和能量消耗的昼夜节律幅度,表明3’-脱氧腺苷有效地恢复了生物钟的正常功能。这一发现具有重要意义，因为昼夜节律的增强意味着生物体能够更好地适应环境变化，从而优化其生理功能。进一步的实验显示，3’-脱氧腺苷改善了肥胖小鼠和老龄鼠的行为和多种生理功能，包括运动协调、肌肉耐力、胰岛素敏感性、脂质稳态和内分泌节律等。这些改善有助于提高老龄鼠的生活质量，也延缓了其衰老的进程。例如，改善运动协调有助于减少跌倒的风险和预防运动障碍的发生，而肌肉耐力的增加则有助于维持体力活动水平。此外，胰岛素敏感性的提高和脂质稳态的改善有助于降低代谢疾病的风险。

在细胞层面上，3’-脱氧腺苷表现出显著的抗衰老效果。研究发现，该化合物能够降低DNA损伤，抑制活性氧（ROS）的产生，减缓衰老细胞的积累，并具有抗炎作用。活性氧的过度产生是导致细胞老化和疾病的重要因素之一，而3’-脱氧腺苷通过抑制ROS的产生，有效地保护了细胞免受氧化损伤。此外，它还可以通过减少衰老细胞的积累，从而减缓组织功能的退化。

从表观遗传学的角度来看，3’-脱氧腺苷改善了与衰老和激素合成及分泌相关通路的节律性，并降低了多种组织的DNA甲基化年龄。DNA甲基化是表观遗传调控的重要机制之一，其变化与衰老密切相关。研究表明，3’-脱氧腺苷能够降低DNA甲基化水平，从而延缓老龄鼠的生物学衰老进程，并延长其生存率。

此外，深入的转录组学分析和c-FOS+ 脑成像揭示了3’-脱氧腺苷作用的靶向脑区，即下丘脑室旁核神经元。下丘脑对生物钟的调节非常关键，该研究发现，通过化学遗传学和光遗传学方法增强这些神经元的昼夜节律，能够有效改善老龄鼠的衰老及代谢紊乱。这些结果不仅为理解3’-脱氧腺苷的具体作用机制提供了新的视角，也为开发新的抗衰老策略提供了关键的靶点。

同时，研究还证实AAA+家族ATPase分子Ruvbl2基因是3’-脱氧腺苷调节PVN神经元生物钟的分子靶点。 Ruvbl2基因在染色质重塑、调节细胞周期和DNA修复等基本生物过程中扮演着重要角色，其与生物钟调节的关系为进一步研究提供了一个崭新的方向。通过干预RUVBL2蛋白作用于生物钟蛋白复合体，调控多种细胞功能，从而实现其抗衰老效应。

综上所述，本研究通过多角度、多层次的实验，深入探讨了3’-脱氧腺苷在调节生物钟以抵抗代谢性疾病及延缓衰老方面的机制和作用。研究强调了调节下丘脑室旁核神经元昼夜节律的潜力，并提出通过优化生物钟功能来促进整体健康和延长寿命的可能性。这一研究不仅为理解老龄化过程中生物钟的变化提供了新的见解，也为开发对抗肥胖和延缓衰老的干预措施奠定了基础。未来，随着对3’-脱氧腺苷及其靶向途径的进一步研究，有望揭示更多关于生物钟与健康老龄化之间的复杂关系，从而为人类健康长寿提供新的策略和希望。

The circadian clock is an internal rhythmic regulation system within organisms that orchestrates various physiological functions, including behavior, metabolism, thermoregulation, and hormone secretion. This internal mechanism is essential for the adaptation and survival of organisms, enabling them to adjust to daily environmental changes and optimize physiological functions and behavioral patterns. However, the regulatory capacity of the circadian clock diminishes with aging. This decline not only affects the quality of life but also accelerates the aging process and increases the risk of chronic diseases such as cardiovascular diseases, metabolic syndrome, and neurodegenerative disorders. Furthermore, obesity negatively influences organ functions throughout the body. Although growing evidence suggests that enhancing circadian clock function can partially slow the progression of these diseases, targeted strategies to restore circadian rhythms to mitigate obesity and age-related diseases and extend lifespan remain lacking. Thus, it is imperative to explore mechanisms for restoring circadian rhythms to promote healthy longevity in aging organisms and protect against metabolic diseases.

This study utilized the small molecule compound 3’-deoxyadenosine，identified through laboratory screening for its circadian clock-regulating properties, to evaluate its potential in promoting healthy longevity in aged mice and protecting against obesity. The effects of this compound on circadian rhythms of locomotor activity and energy expenditure, as well as cellular senescence markers，were observed in aging and high-fat diet induced obesity mice, and further investigated the molecular and neuronal mechanisms through transcriptomic analysis, epigenetic profiling, whole-brain immunofluorescence c-FOS+ brain mapping, chemogenetics, and optogenetics.

Our results showed that 3’-deoxyadenosine significantly enhanced the rhythms of locomotor activity, the synthesis and secretion of endocrine hormones, and energy expenditure in obesity and aging mice, suggesting that 3’-deoxyadenosine effectively restores normal circadian clock function. This finding is significant because an increased circadian rhythm amplitude suggests improved adaptation to environmental changes and optimized physiological functions. Further experiments revealed that 3’-deoxyadenosine improved both behavioral and physiological functions in obesity and aging mice, including motor coordination, muscle endurance, insulin sensitivity, lipid homeostasis, and endocrine rhythms. These improvements contributed to enhanced the quality of life and slowed aging process in aged mice. For instance, improved motor coordination may reduce the risk of falls and prevent movement disorders, and increased muscle endurance supports maintaining physical activity levels. Additionally, enhanced insulin sensitivity and improved lipid homeostasis reduce the risk of metabolic diseases.

At the cellular level, 3’-deoxyadenosine exhibits significant anti-aging effects. The compound reduced DNA damage, inhibited the production of reactive oxygen species (ROS), slowed the accumulation of senescent cells, and attenuated inflammaging. The overproduction of reactive oxygen species (ROS) is a key factor contributing to cellular aging and disease, and 3’-deoxyadenosine effectively protects cells from oxidative damage by inhibiting ROS production. Additionally, it slows the degradation of tissue function by reducing the accumulation of senescent cells.

From an epigenetic perspective, 3’-deoxyadenosine improves the rhythmicity of pathways associated with aging，as well as hormone synthesis and secretion, and reduces DNA methylation age in multiple tissues. DNA methylation is one of the important mechanisms of epigenetic regulation, and its alterations are closely associated with aging. 3’-deoxyadenosine was shown to reduce DNA methylation levels, thereby slowing biological aging process and extending the lifespan of aged mice.

Additionally, comprehensive transcriptomic analysis and whole-brain c-FOS+ brain mapping identified the hypothalamic paraventricular nucleus (PVN) as the primary brain region targeted by 3’-deoxyadenosine. The hypothalamus plays a crucial role in the regulation of the biological clock, and the study found that enhancing the circadian rhythms of PVN neurons through chemogenetic and optogenetic approaches effectively mitigated aging and metabolic disorders in aged mice. These results provide new insights into the specific mechanisms of 3’-deoxyadenosine action and identify crucial targets for developing novel anti-aging strategies.

Furthermore, the study confirmed that the Ruvbl2 gene, a member of the AAA+ family of ATPases, serves as a molecular target for 3'-deoxyadenosine in regulating the biological clock of PVN neurons. The Ruvbl2 gene plays an important role in fundamental biological processes such as chromatin remodeling, cell cycle regulation, and DNA repair, and its relationship with biological clock regulation provides a novel direction for further research. By intervening in the action of RUVBL2 protein on the biological clock protein complex, various cellular functions can be regulated, thereby achieving its anti-aging effects.

In summary, this study investigated the effects and mechanisms of 3’-deoxyadenosine in regulating the circadian clock to combat metabolic disease and delay aging through multi-faceted and multi-layered experiments. The research highlights the potential of modulating circadian rhythms in PVN neurons and suggests the possibility of promoting overall health and extending lifespan by optimizing circadian clock function. This study not only provides new insights into circadian clock changes during aging but also lays the groundwork for developing interventions to slow aging and combat obesity disease. As research into 3’-deoxyadenosine and its targeted pathways progresses, it is anticipated that more will be revealed about the complex relationship between circadian clocks and healthy aging, offering new strategies and hope for human health and longevity.