DZPG-CIRC: Immune mechanisms in mental health

Project partners
Christian Geis (J), Ildiko Dunay (MD), Johann Steiner (MD)
Young DZPG: Dr. rer. med. Patrick Müller (Kardiologie, DZNE Magdeburg), Dr. med. Alexander Refisch (Psychiatrie Jena), Dr. med. Ha-Yeun Chung (Neurologie Jena)
Central project: JE4: immune mechanisms;
Related project: JE1: circuit mechanisms, JE5 physico-mental Interplay cardiometabolic dimension
Associated partner: Axel Brakhage (J) microbiome analysis;
Collaboration within CIRC: see PIs above; further possible internal collaborations: Mathias Pletz/Sebastian Weis (J) patient cohorts and metabolic cages (mouse models), S. Remy (MD) circuit analysis; V. Leßmann (MD) synaptic plasticity, R. Stumm (J) transgenic animal models for immune cell fate mapping; A. Haghikia (MD)
Possible collaboration within DZPG: J. Priller (Munich) microglia involvement in disease pathology
PPI association: Patients, family members and the Trialogical Advisory Board will be included in data acquisition, interpretation and development of ideas for intervention strategies
Project summary:
The project aims at elucidating how inflammation-triggered immune mechanisms influence mental health. Based on preliminary work and current knowledge we will focus on cognitive dysfunction and depression for which a direct link to systemic and CNS immune activation has been established. To this end, we propose to (i) characterize neuropsychiatric symptoms and perform immunophenotyping in patients with systemic inflammation and in patients with atypical depression which is known to be associated with low-grade inflammation and to (ii) unravel mechanistic events of immune-mediated brain dysfunction leading to neuropsychiatric disease.
WP1 C. Geis will explore mechanistic events how severe systemic inflammation affects neuronal function and induces brain circuit pathology. Here, we will apply a well established polymicrobial infection mouse model in transgenic mouse lines to investigate innate immune cell activation and fate mapping at CNS border areas. Resulting neuronal circuit dysfunction will be determined by standardized behavioral phenotyping (cognition, anxiety, and depressive behavior) together with patch-clamp electrophysiology and analysis and computational modeling of hippocampal network oscillations and plasticity. Following projects will address interventional strategies using immune cell depletion or modification using genetic and pharmacological approaches.
WP2 IR. Dunay will investigate longitudinally 1) cytokine profile and soluble neurodegenerative markers in patients with typical / atypical depression 2) correlate the data with microglia and blood-brain-barrier-derived extracellular vesicles (EV) from plasma as novel biomarker for disease severity and progression 3) functional characterize the peripheral blood mononuclear cells (PBMC surface receptors, intracellular cell-subtype-specific cytokine production, phagocytic capacity as well as metabolic profile) to gain a deeper understanding of the immunological processes underlying depression and treatment effectiveness. In addition, in the murine model from Christian Geis, the synaptic changes will be elucidated by the newly established method: Flow Synaptometry. V. Leßmann (Physiology, Magdeburg) will support these immune tests and investigate the topic of neuroregeneration e.g. by concomitant BDNF analyses.
WP3 J. Steiner will 1.) continue to recruit clinically patients with typical / atypical depression, including clinical ratings and blood sampling (established biobanking since 2007); 2.) immunocharacterize the blood samples via Flow cytometry (link to I. Dunay) and perform neutrophil function tests in patients and matched controls. Moreover, he will test if disturbances of the intestinal barrier (surrogate markers: Zonula occludens-1, Occludin & Claudin-5, Intestinal-fatty acid binding protein / I-FABP, Mucin 2 / MUC2) or blood-CSF-barrier (albumin CSF-serum-ratio) are associated with the identified immunometabolic and microbiome abnormalities in atypical depression (link to A. Brakhage & A. Haghikia).