Urolithin A abolishes high anxiety and rescues the associated mitochondrial transcriptomic signatures and synaptic function

Background Chronic anxiety imposes a major global health burden, yet existing treatments remain inadequate, with limited efficacy or significant side effects. Mitochondrial abnormalities have emerged as key contributors to anxiety-related phenotypes, suggesting that targeting mitochondrial function may offer a novel therapeutic avenue. Urolithin A (UA), a gut microbiota-derived metabolite known to enhance mitochondrial function, has shown neuroprotective effects in preclinical models of aging and neurodegeneration. However, its potential in modulating anxiety and underlying neuronal mechanisms remains unexplored. Methods We examined the effects of UA in two rodent models of heightened anxiety: a natural variation model and a genetically selected high stress-reactivity line. Animals received chronic UA supplementation, and anxiety-like behaviors were assessed across multiple paradigms. Single-nucleus RNA sequencing was performed to identify molecular alterations in nucleus accumbens (NAc) medium spiny neurons (MSNs), incorporating MitoPathway analyses to examine mitochondrion-related transcriptomic signatures. Electrophysiological, immunohistochemical, and morphological analyses were conducted to assess mitochondrial pathways and synaptic function. Results UA selectively reduced anxiety-like behaviors in high-anxiety animals, both males and females, leaving non-anxious controls unaffected. Transcriptomic analyses revealed widespread mitochondrial and synaptic dysregulation in high-anxiety MSNs, with impaired mitophagy emerging as a core feature. UA treatment restored these transcriptomic signatures, normalizing mitophagy-related pathways across all MSN subtypes tightly linked to restored synaptic pathways. These changes translated into structural and functional rescue of MSN dendritic architecture, spine density, and excitatory synaptic transmission. Conclusions These findings identify mitophagy deficits in NAc MSNs as a hallmark of heightened anxiety and highlight UA as a promising mechanism-based intervention.背景 慢性焦虑已构成重大全球健康负担，但现有治疗手段仍存在不足，存在疗效有限或副作用显著的问题。线粒体异常已被证实是焦虑相关表型的关键致病因素，这提示靶向线粒体功能或许能开辟全新的治疗途径。尿石素A（Urolithin A，UA）是一种肠道菌群衍生的代谢物，已知可增强线粒体功能，在衰老与神经退行性疾病的临床前模型中已展现出神经保护作用。然而，其在调节焦虑及潜在神经元机制方面的潜力仍未得到探索。 方法 本研究针对两种焦虑加剧的啮齿动物模型探究UA的作用效果：自然变异模型与经遗传筛选的高应激反应品系。对动物进行长期UA给药，并通过多种实验范式评估其类焦虑行为。通过单细胞核RNA测序鉴定伏隔核（nucleus accumbens，NAc）中型多棘神经元（medium spiny neurons，MSNs）的分子改变，并结合MitoPathway分析探究线粒体相关转录组特征。开展电生理、免疫组织化学及形态学分析，以评估线粒体通路与突触功能。 结果 UA可选择性降低高焦虑动物（包括雄性与雌性）的类焦虑行为，而对非焦虑对照组无影响。转录组分析显示，高焦虑状态下的MSNs存在广泛的线粒体与突触功能失调，其中受损的线粒体自噬是核心特征之一。UA给药可修复这些转录组特征，使所有与突触通路恢复紧密相关的MSN亚型的线粒体自噬相关通路恢复正常。这些变化最终实现了MSN树突结构、棘突密度与兴奋性突触传递的结构与功能修复。 结论 本研究证实伏隔核MSNs的线粒体自噬缺陷是焦虑加剧的标志性特征，并揭示UA是一种极具前景的基于机制的干预手段。