Voss, O. | Search bioRxiv

bioRxiv2024

Altered physiological, affective, and functional connectivity responses to acute stress in patients with alcohol use disorder

BackgroundThere is evidence that the processing of acute stress is altered in alcohol use disorder (AUD), but little is known about how this is manifested simultaneously across different stress parameters and which neural processes are involved. The present study examined physiological and affective responses to stress and functional connectivity in AUD. MethodsSalivary cortisol samples, pulse rate, and affect ratings were collected on two days from 34 individuals with moderate or severe AUD and 34 controls. On one day, stress was induced, and on the other day, a non-stressful control task was performed. Following the intervention, participants underwent fMRI to assess functional connectivity, focusing on cortical and subcortical seed regions previously reported to be involved in AUD and/or stress. ResultsFor pulse rate and cortisol, stress responses were blunted in AUD, whereas negative affect was increased. Furthermore, stress-related changes in pulse rate, cortisol, and affect were only correlated in healthy controls. Neuroimaging analyses revealed stress-related group differences in functional connectivity, involving the connectivity of striatal seeds with the posterior DMN, cerebellum and midcingulate cortex, and of the posterior DMN seed with the striatum and thalamus. ConclusionsThe results suggest a dissociation between subjective experienced distress and the physiological stress response in AUD as well as stress-related alterations in functional connectivity. These findings highlight the complex interplay between chronic alcohol use and acute stress regulation, offering valuable considerations for the development of therapeutic strategies.

neuroscience↗

bioRxiv2022

Pathogenic Rickettsia species evade autophagosomal maturation and reduce anti-microbicidal pro-inflammatory IL-1 responses to support their intracellular survival.

Species of genus Rickettsia are obligate intracellular bacterial parasites of a wide range of arthropod and vertebrate hosts. Some Rickettsia species are responsible for several serious human diseases. One fascinating feature of these stealthy group of pathogens is their ability to exploit host cytosolic defense responses to their benefits. However, the precise mechanism by which pathogenic Rickettsia elude host immune defense responses remains to be determined. Here, we observed that pathogenic R. typhi and R. rickettsii, but not non-pathogenic R. montanensis become ubiquitinated and induce autophagy upon entry into bone-marrow-derived macrophages. Moreover, unlike R. montanensis, R. typhi, and R. rickettsii colocalized with LC3B but not with Lamp2 upon host cell entry. Finally, we observed that pathogenic but not non-pathogenic Rickettsia reduce pro-inflammatory IL-1 responses. In sum, we identified a previously unappreciated pathway by which pathogenic, but not non-pathogenic, Rickettsia become ubiquitinated and induced autophagy, but avoided autophagolysosomal destruction as well as inflammasome-mediated anti-microbicidal IL-1 cytokine responses to establish an intracytosolic niche in macrophages.

microbiology↗