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. Outbred Wistar rats were classified based on their anxiety profiles using elevated plus maze and open field/novel object tests. Half of the high anxious (HA) group received Urolithin A for two months (HAUA), followed by sacrifice and acquisition of the Nucleus Accumbens punches. Nuclei isolation was performed on the punches, followed by library preparation with Chromium Single Cell 3’ Library & Gel Bead Kit v3.1 (10x Genomics)