Stress, immune mechanisms, and mental illness: from etiology to treatment

It is now well-established that a strong relationship exists between psychiatric disorders and disturbances of immune mechanisms at different stages of life. Indeed, a derangement in the expression and function of specific immune elements may predispose and contribute to the development of different psychopathologic conditions and could also represent an important component that must be targeted by therapeutic intervention. The proposed symposium will summarize authoritatively the important recent advances on the immune mechanisms contributing to the etiology of psychiatric disorders, with a specific focus on the role of stress, and it will discuss if and how the effectiveness of therapeutic intervention may depend on the ability to regulate immune mechanisms that are altered under pathologic conditions. The symposium will unfold upon the discussion of preclinical and clinical studies addressing different aspects related to psychiatric disorders. Prof. A. Pillai (University of Texas, U.S.A.) will specifically discuss the roles of neuroinflammation and synapse loss in IFN-I signaling-mediated social deficits under chronic stress conditions. He will discuss how peripheral blockade of IFN-I signaling attenuated stress-induced neuroimmune alterations and social behavioral deficits and also the key role of complement component 3a receptor 1 (C3ar1) in these mechanisms. Along this line, Prof. M.A. Riva (University of Milan, Italy) will show how immune mechanisms and dysregulation of microglial function may contribute to the vulnerability to stress at different life stages, from adolescence to adulthood. Moreover, he will discuss how the normalization of some of these mechanisms following pharmacological intervention may contribute to therapeutic effectiveness in the treatment of different psychiatric disorders characterized, particularly in patients characterized by a higher inflammatory status. At the clinical level, Dr. G. Scaini (University of Texas, U.S.A.) will discuss the interplay between inflammation, stress, and mitochondria in bipolar disorder patients. She will highlight the significant correlation between alterations in mitochondrial proteins and inflammatory markers with a decrease in functional status and an increase in the severity of symptoms. Lastly, Prof. J. Felger (Emory Univ.) will discuss how depressed patients with increased inflammation show altered functional connectivity within the ventral striatum to ventromedial prefrontal cortex reward circuitry in relation to symptoms of anhedonia. These changes can be improved by pharmacological intervention aimed to increase dopamine levels suggesting that functional connectivity in reward circuitry may also serve as a modifiable imaging biomarker for the efficacy of pharmacological and/or behavioral interventions to reverse the impact of inflammation on the brain of depressed subjects.