This K23 proposal is designed to provide the applicant with protected time, resources and a supervised research experience that will facilitate the development of an independent research career at the interface of behavioral immunology and neuroimaging. Neuropsychiatric disorders including depression in the medically ill are of significant public health concern, occurring in up to 50% of patients and having a major impact on treatment adherence, quality of life, morbidity and mortality. Mounting data indicate that peripheral immune system activation/inflammation and the associated release of inflammatory cytokines may play a role in the development of neuropsychiatric disorders including depression in the medically ill as well as in medically healthy individuals. Nevertheless, few studies have examined the impact of peripherally elaborated cytokines on the brain, especially the metabolism of relevant CNS cell types including both neurons and glia. The long- term objective of the proposed research and career development plan is to utilize neuroimaging technologies such as magnetic resonance spectroscopy (MRS) to measure the consequences of peripheral inflammation on brain metabolism during depression. To accomplish this goal, the applicant proposes a training plan which encompasses: a) a comprehensive set of didactics in behavioral neuroscience, neuroimaging and immunology, b) one-on-one supervision with a primary mentor and consultants, and c) a hands-on supervised research experience. The research project aims to study the association between inflammatory cytokines and behavior and makes use of the model of neuropsychiatric symptoms precipitated by the inflammatory cytokine, interferon (IFN)-alpha. Previous work in the mentor's laboratory has established that administration of IFN-alpha to humans reliably causes symptoms of depression while inducing a CNS inflammatory response. Thus, IFN-alpha provides a unique model system for testing neuroimaging strategies such as MRS to identify metabolic processes that may participate in behavioral changes that occur in the context of inflammation. The primary aim of the proposed research is to test the hypothesis that IFN-alpha-induced behavioral and cognitive changes will be associated with increased markers of glial activation and excitatory neurotransmission, accompanied by decreased markers of neuronal viability. These CNS metabolic changes in turn will be associated with activation of CNS inflammatory responses and cytokine-induced increases in excitotoxic kynurenine metabolites, including quinolinic acid. To test these hypotheses, 50 adult patients with hepatitis C will be studied pre- and post-IFN-alpha. Concentrations of biomarkers of glial activation, excitotoxicity and neuronal dysfunction in relevant brain regions including the basal ganglia will be measured by single voxel proton MRS and correlated with blood and cerebrospinal fluid biomarkers of immune activation and kynurenine metabolism. Aside from providing important insight into the mechanism by which cytokines influence behavior, these data will provide a foundation for the applicant's elaboration of an independent research program.

Public Health Relevance

This K23 proposal is designed to promote the career development of the applicant, while also exploring novel brain imaging methods to investigate the impact of the immune system on the brain. Cytokines released by an activated immune system have been associated with the development of depression in both medically ill and medically healthy individuals. The proposed research will explore the mechanism of these effects by using advanced neuroimaging strategies to measure brain metabolism before and after cytokine administration and relate changes in brain metabolism to cytokine-induced changes in behavior.

National Institute of Health (NIH)
National Institute of Mental Health (NIMH)
Mentored Patient-Oriented Research Career Development Award (K23)
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Biobehavioral Mechanisms of Emotion, Stress and Health Study Section (MESH)
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Chavez, Mark
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Emory University
Schools of Medicine
United States
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Mehta, Neeti D; Haroon, Ebrahim; Xu, Xiaodan et al. (2018) Inflammation negatively correlates with amygdala-ventromedial prefrontal functional connectivity in association with anxiety in patients with depression: Preliminary results. Brain Behav Immun 73:725-730
Haroon, Ebrahim; Chen, Xiangchuan; Li, Zhihao et al. (2018) Increased inflammation and brain glutamate define a subtype of depression with decreased regional homogeneity, impaired network integrity, and anhedonia. Transl Psychiatry 8:189
Haroon, Ebrahim; Miller, Andrew H; Sanacora, Gerard (2017) Inflammation, Glutamate, and Glia: A Trio of Trouble in Mood Disorders. Neuropsychopharmacology 42:193-215
Goldsmith, David R; Haroon, Ebrahim; Woolwine, Bobbi J et al. (2016) Inflammatory markers are associated with decreased psychomotor speed in patients with major depressive disorder. Brain Behav Immun 56:281-8
Felger, Jennifer C; Haroon, Ebrahim; Woolwine, Bobbi J et al. (2016) Interferon-alpha-induced inflammation is associated with reduced glucocorticoid negative feedback sensitivity and depression in patients with hepatitis C virus. Physiol Behav 166:14-21
Haroon, E; Fleischer, C C; Felger, J C et al. (2016) Conceptual convergence: increased inflammation is associated with increased basal ganglia glutamate in patients with major depression. Mol Psychiatry 21:1351-7
Felger, J C; Li, Z; Haroon, E et al. (2016) Inflammation is associated with decreased functional connectivity within corticostriatal reward circuitry in depression. Mol Psychiatry 21:1358-65
Felger, Jennifer C; Haroon, Ebrahim; Miller, Andrew H (2015) Risk and Resilience: Animal Models Shed Light on the Pivotal Role of Inflammation in Individual Differences in Stress-Induced Depression. Biol Psychiatry 78:7-9
Haroon, Ebrahim; Felger, Jennifer C; Woolwine, Bobbi J et al. (2015) Age-related increases in basal ganglia glutamate are associated with TNF, reduced motivation and decreased psychomotor speed during IFN-alpha treatment: Preliminary findings. Brain Behav Immun 46:17-22
Rilling, James K; Demarco, Ashley C; Hackett, Patrick D et al. (2014) Sex differences in the neural and behavioral response to intranasal oxytocin and vasopressin during human social interaction. Psychoneuroendocrinology 39:237-48

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