Chidomere, C. L. | bioRxiv Science

bioRxiv2025

Activation of the cGAS-STING pathway contributes to cancer-related fatigue in a murine model of head and neck cancer

Cancer-related inflammation and metabolic alterations extend beyond the tumor microenvironment, exerting systemic effects that disrupt energy homeostasis and contribute to reduced physical function and chronic fatigue. The cGAS-STING pathway has emerged as a key regulator of innate immunity and inflammation; however, its role in cancer-associated fatigue remains poorly understood. In this study, we investigated the contribution of cGAS- STING-mediated inflammation to cancer- and/or its treatment-induced fatigue using a mouse model of human papillomavirus-related head and neck cancer. Wheel running activity, along with inflammatory and metabolic changes in tumor and liver tissues, were assessed following chemoradiotherapy and pharmacological inhibition of STING in tumor-bearing and tumor-free control mice. The results revealed that tumor growth and chemoradiotherapy activated the cGAS-STING pathway, together with an upregulation of proinflammatory mediators and alterations of mitochondrial and metabolic gene expression in the liver. To inhibit STING activation, mice were administered H-151, a specific STING antagonist. This intervention attenuated hepatic inflammatory signatures and mitigated tumor and/or chemoradiotherapy-associated behavioral fatigue measured by decreased voluntary wheel running. These findings implicate for the first time the cGAS-STING signaling pathway and metabolic homeostasis in cancer- and cancer therapy-related fatigue.

cancer biology↗

bioRxiv2024

Neural signatures of opioid-induced risk-taking behavior in the prelimbic prefrontal cortex

Opioid use disorder occurs alongside impaired risk-related decision-making, but the underlying neural correlates are unclear. We developed an approach-avoidance conflict task using a modified conditioned place preference procedure to study neural signals of risky opioid seeking in the prefrontal cortex, a region implicated in executive decision-making. Following morphine conditioned place preference, rats underwent a conflict test in which fear-inducing cat odor was introduced in the previously drug-paired side of the apparatus. While the saline-exposed control group avoided cat odor, the morphine group included two subsets of rats that either maintained a preference for the paired side despite the presence of cat odor (Risk-Takers) or exhibited increased avoidance (Risk-Avoiders), as revealed by K-means clustering. Single-unit recordings from the prelimbic cortex (PL) demonstrated decreased neuronal activity upon acute morphine exposure in both Risk-Takers and Risk-Avoiders, but this firing rate suppression was absent after repeated morphine administration. Risk-Avoiders also displayed distinct post-morphine excitation in PL which persisted across conditioning. During the preference test, subpopulations of PL neurons in all groups were either excited or inhibited when rats entered the paired side. Interestingly, the inhibition in PL activity was lost during the subsequent conflict test in both saline and Risk-Avoider groups, but persisted in Risk-Takers. Additionally, Risk-Takers showed an increase in the proportion of PL neurons displaying location-specific firing in the drug-paired side from the preference to the conflict test. Together, our results suggest that persistent PL inhibitory signaling in the drug-associated context during motivational conflict may underlie increased risk-taking behavior following opioid exposure. SIGNIFICANCE STATEMENTRisky opioid use is well established in opioid use disorder, but the underlying neural correlates are poorly understood. In this study, we present findings from a novel behavioral task in which rats face a motivational conflict between contextual opioid reward memory and a naturalistic predator threat. Performing neuronal recordings in the prelimbic prefrontal cortex (PL), a brain region critical for executive decision-making, we demonstrate enhanced representation of drug-associated context and persistent inhibitory signaling by PL neurons that occur alongside opioid-induced risk-taking behavior. Our findings refine a preclinical model for studying addiction, establish PL as a prime region for investigating drug-environment interactions, and positions the prefrontal cortex as a candidate region for translational studies targeting risky opioid use.

neuroscience↗