Browsing by Author "Hodes, Georgia E."

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    Altered peripheral immune profiles in treatment-resistant depression: response to ketamine and prediction of treatment outcome.
    Kiraly, D. D.; Horn, S. R.; Van Dam, N. T.; Costi, S.; Schwartz, J.; Kim-Schulze, S.; Patel, M.; Hodes, Georgia E.; Russo, Scott J.; Merad, Miriam; Iosifescu, D. V.; Charney, D. S.; Murrough, J.W. (2017-03-21)
    A subset of patients with depression have elevated levels of inflammatory cytokines, and some studies demonstrate interaction between inflammatory factors and treatment outcome. However, most studies focus on only a narrow subset of factors in a patient sample. In the current study, we analyzed broad immune profiles in blood from patients with treatment-resistant depression (TRD) at baseline and following treatment with the glutamate modulator ketamine. Serum was analyzed from 26 healthy control and 33 actively depressed TRD patients free of antidepressant medication, and matched for age, sex and body mass index. All subjects provided baseline blood samples, and TRD subjects had additional blood draw at 4 and 24 h following intravenous infusion of ketamine (0.5 mg kg-1). Samples underwent multiplex analysis of 41 cytokines, chemokines and growth factors using quantitative immunoassay technology. Our a priori hypothesis was that TRD patients would show elevations in canonical pro-inflammatory cytokines; analyses demonstrated significant elevation of the pro-inflammatory cytokine interleukin-6. Further exploratory analyses revealed significant regulation of four additional soluble factors in patients with TRD. Several cytokines showed transient changes in level after ketamine, but none correlated with treatment response. Low pretreatment levels of fibroblast growth factor 2 were associated with ketamine treatment response. In sum, we found that patients with TRD demonstrate a unique pattern of increased inflammatory mediators, chemokines and colony-stimulating factors, providing support for the immune hypothesis of TRD. These patterns suggest novel treatment targets for the subset of patients with TRD who evidence dysregulated immune functioning.
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    Crystallin Mu in Medial Amygdala Mediates the Effect of Social Experience on Cocaine Seeking in Males but Not in Females
    Walker, Deena M.; Zhou, Xianxiao; Cunningham, Ashley M.; Ramakrishnan, Aarthi; Cates, Hannah M.; Lardner, Casey K.; Pena, Catherine J.; Bagot, Rosemary C.; Issler, Orna; van der Zee, Yentl; Lipschultz, Andrew P.; Godino, Arthur; Browne, Caleb J.; Hodes, Georgia E.; Parise, Eric M.; Torres-Berrio, Angelica; Kennedy, Pamela J.; Shen, Li; Zhang, Bin; Nestler, Eric J. (Elsevier, 2022-06-30)
    Background: Social experiences influence susceptibility to substance use disorder. The adolescent period is associated with the development of social reward and is exceptionally sensitive to disruptions to reward-associated behaviors by social experiences. Social isolation (SI) during adolescence alters anxiety- and reward-related behaviors in adult males, but little is known about females. The medial amygdala (meA) is a likely candidate for the modulation of social influence on drug reward because it regulates social reward, develops during adolescence, and is sensitive to social stress. However, little is known regarding how the meA responds to drugs of abuse. Methods: We used adolescent SI coupled with RNA sequencing to better understand the molecular mechanisms underlying meA regulation of social influence on reward. Results: We show that SI in adolescence, a well-established preclinical model for addiction susceptibility, enhances preference for cocaine in male but not in female mice and alters cocaine-induced protein and transcriptional profiles within the adult meA particularly in males. To determine whether transcriptional mechanisms within the meA are important for these behavioral effects, we manipulated Crym expression, a sex-specific key driver gene identified through differential gene expression and coexpression network analyses, specifically in meA neurons. Overexpression of Crym, but not another key driver that did not meet our sex-specific criteria, recapitulated the behavioral and transcriptional effects of adolescent SI. Conclusions: These results show that the meA is essential for modulating the sex-specific effects of social experience on drug reward and establish Crym as a critical mediator of sex-specific behavioral and transcriptional plasticity.
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    Differential regulation of herpes simplex virus-1 and herpes simplex virus-2 during latency and post reactivation in response to stress hormones and nerve trauma in primary adult sensory and sympathetic neurons
    Goswami, Poorna (Virginia Tech, 2022-08-18)
    The contrasting infection strategy of herpes simplex virus (HSV) consists of an initial primary lytic infection in epithelial cells, followed by establishment of lifelong latency in sensory and autonomic neurons of the peripheral nervous system that innervate the site of infection. Any cellular stress trigger, ranging from external stimuli such as UV radiation or nerve injury to psychological and physiological stress, can reactivate HSV from latency in the neurons, resulting in recurrent disease episodes. Stress hormones and deprivation of neurotrophic factor (NTF) both have a strong correlation with HSV reactivation from neurons. However, neuronal signaling pathways cardinal to HSV latency and reactivation are still not clear. This dissertation provides new understanding of HSV latency and reactivation in response to two orthogonal stress stimuli, viz. stress hormones epinephrine (EPI) and corticosterone (CORT), as well as NTF deprivation that simulates a nerve injury in primary neuronal cultures. In this dissertation, we demonstrate that physiological stress hormones EPI and CORT differentially regulate HSV-1 and HSV-2 reactivation in adult neurons. Both EPI and CORT treatment reactivated only HSV-1 in sympathetic superior cervical ganglia (SCG) neurons, while HSV-2 was reactivated only by CORT in both sensory trigeminal ganglia (TG) neurons and sympathetic superior cervical (SCG) neurons. EPI utilized the combination of α and β adrenergic receptor complex, while CORT signaled through glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) to reactivate HSV in the neurons. NTFs are tissue-target derived growth factors required for neuronal protection and survival. Neurotrophins are also required for maintaining HSV latency, as NTF deprivation reactivates both HSV-1 and HSV-2 in adult sensory TG and sympathetic SCG neurons. In addition, assessing the temporal kinetics of HSV gene expression showed differential expression profiles of viral immediate-early (IE) genes ICP0, ICP4, ICP27 and trans-activator VP16 following treatment with stress hormones and NTF deprivation in HSV-1 and HSV-2 infected neurons. We also show that different molecular mechanisms are involved in HSV latency and reactivation, which are dependent on the stimuli and the type of neurons. Tyrosine kinase receptor-mediated PI3K-Akt-mTORC signaling cascades have been studied for their role in maintaining HSV latency. Activation of β-catenin signalosome expression has also been implicated during HSV latency and following reactivation. GSK3β is a key effector molecule that inter-connects Akt and β-catenin mediated pathways, forming an Akt-GSK3β-β-catenin signaling axis. Analyzing the Akt-GSK3β-β-catenin signaling in response to stress hormone and NTF deprivation revealed significant differences in protein expression levels between HSV-1 and HSV-2 infected sensory and sympathetic neurons. In HSV-1 infected neurons, the Akt-GSK3β-β-catenin maintains the signal transmission in order to keep the neurons alive, but HSV-2 infections obliterated the entire axis in the adult neurons, particularly in sympathetic neurons. In summary, we demonstrate that HSV-1 and HSV-2 do not have a 'one for all' infection mechanism. Establishment of latency and reactivation by HSV is virus specific, stimulus specific and neuron specific.
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    Epigenetic modulation of inflammation and synaptic plasticity promotes resilience against stress in mice
    Wang, Jun; Hodes, Georgia E.; Zhang, Hongxing; Zhang, Song; Zhao, Wei; Golden, Sam A.; Bi, Weina; Menard, Caroline; Kana, Veronika; Leboeuf, Marylene; Xie, Marc; Bregman, Dana; Pfau, Madeline L.; Flanigan, Meghan E.; Estebam-Fernández, Adelaida; Yemul, Shrishailam; Sharma, Ali; Ho, Lap; Dixon, Richard A.; Merad, Miriam; Han, Ming-Hu; Russo, Scott J.; Pasinetti, Giulio M. (Nature, 2018)
    Major depressive disorder is associated with abnormalities in the brain and the immune system. Chronic stress in animals showed that epigenetic and inflammatory mechanisms play important roles in mediating resilience and susceptibility to depression. Here, through a highthroughput screening, we identify two phytochemicals, dihydrocaffeic acid (DHCA) and malvidin-3′-O-glucoside (Mal-gluc) that are effective in promoting resilience against stress by modulating brain synaptic plasticity and peripheral inflammation. DHCA/Mal-gluc also significantly reduces depression-like phenotypes in a mouse model of increased systemic inflammation induced by transplantation of hematopoietic progenitor cells from stresssusceptible mice. DHCA reduces pro-inflammatory interleukin 6 (IL-6) generations by inhibiting DNA methylation at the CpG-rich IL-6 sequences introns 1 and 3, while Mal-gluc modulates synaptic plasticity by increasing histone acetylation of the regulatory sequences of the Rac1 gene. Peripheral inflammation and synaptic maladaptation are in line with newly hypothesized clinical intervention targets for depression that are not addressed by currently available antidepressants.
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    Estrogen receptor α drives pro-resilient transcription in mouse models of depression
    Lorsch, Zachary S.; Loh, Yong-Hwee Eddie; Purushothaman, Immanuel; Walker, Deena M.; Parise, Eric M.; Salery, Marine; Cahill, Michael E.; Hodes, Georgia E.; Pfau, Madeline L.; Kronman, Hope; Hamilton, Peter J.; Issler, Orna; Labonte, Benoit; Symonds, Ann E.; Zucker, Matthew; Zhang, Tie Yuan; Meaney, Michael J.; Russo, Scott J.; Shen, Li; Bagot, Rosemary C.; Nestler, Eric J. (Nature Publishing Group, 2018-03-16)
    Most people exposed to stress do not develop depression. Animal models have shown that stress resilience is an active state that requires broad transcriptional adaptations, but how this homeostatic process is regulated remains poorly understood. In this study, we analyze upstream regulators of genes differentially expressed after chronic social defeat stress. We identify estrogen receptor α (ERα) as the top regulator of pro-resilient transcriptional changes in the nucleus accumbens (NAc), a key brain reward region implicated in depression. In accordance with these findings, nuclear ERα protein levels are altered by stress in male and female mice. Further, overexpression of ERα in the NAc promotes stress resilience in both sexes. Subsequent RNA-sequencing reveals that ERα overexpression in NAc reproduces the transcriptional signature of resilience in male, but not female, mice. These results indicate that NAc ERα is an important regulator of pro-resilient transcriptional changes, but with sex-specific downstream targets.
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    Evaluation of Sex Differences in the Hippocampus and Pituitary of Egr1 conditional knockout mice mediated by Nestin-Cre
    Swilley, Cody Lynn (Virginia Tech, 2023-08-29)
    Early growth response 1 (Egr1) is a transcription factor critical for learning and memory in the hippocampus and pituitary cell differentiation. Egr1 has been shown to extend continuation of the long-term potentiation in the hippocampus and is credited for forming long-term memories. The somatotrophs in the pituitary produce growth hormone and are found to be decreased in Egr1KO mice. These animals are also found to be sterile due to a decrease in LHB, which blocks ovulation. All previous studies have evaluated these physiological processes with complete Egr1KO research strains or antisense oligonucleotides, up until now, no data specific to individual type of cells has been generated. In an attempt to focus on the understanding of the functions of Egr1 gene in neural cell lineage, we are using an Egr1cKO Nestin-Cre model. Nestin allows for targeting neuronal lineage specific cells. In Chapter 1, we provide a systemic view of Egr1 gene and Nestin-Cre as a system for generating conditional knockout mouse strains. The Chapter begins with the identification of Egr1 gene and its protein structure, then proceeds to grasp its link to memory with behavior testing. The critical role of Egr1 in the pituitary and what cell populations are affected is also described. The same goes for Nestin-Cre, along with its limitations and understanding how to account for them in a study. The Egr1cKO Nestin-Cre system is the best form to understand neurological cell populations with Egr1 removal. In Chapter 2 and Chapter 3, we employ the Egr1cKO Nestin-Cre mouse model to understand cell-specific knockout of Egr1 in the nervous system by evaluating the hippocampus and pituitary. We explore learning and memory through behavioral tests and ribonucleic acid sequencing (RNA-seq) analysis to understand gene expression changes with Egr1 removal. Females showed higher activity during behavior tests, with more movement in the elevated plus maze and lower freezing times during the contextual fear conditioning. RNA-seq had higher changes in females than males but was not affected by the Nestin-Cre system overall. The same RNA-seq changes in the pituitary gland were present, with females having higher genomic differentiation. Females had growth-specific pathways altered by Nestin-Cre.
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    Investigation of somatomotor-sympathetic brain circuit abnormalities in two rat models featuring inborn differences in emotional behavior
    Shupe, Elizabeth Anne (Virginia Tech, 2023-07-27)
    Major depressive disorder (MDD) features symptoms spanning cognitive, affective, behavioral, and physiological domains. While many of the neural circuit disruptions mediating emotional and cognitive disturbances in depression have been described, far fewer studies have explored neurobiological mechanisms underlying its associated motor or physiological impairments. Emotionally motivated behaviors, including responses to stress, are characterized by concomitant somatomotor actions and autonomic changes that require intricate coordination of the motor and autonomic systems. Prior investigations by our group used a pseudorabies virus (PRV)-mediated retrograde tract-tracing approach to identify brain regions with parallel descending premotor and presympathetic efferents that play a role in integrating somatomotor and sympathetic functions. Several nodes of this circuitry, including the hypothalamic paraventricular nucleus (PVN), locus coeruleus (LC), and periaqueductal gray (PAG), are implicated in responses to stressful and emotionally salient stimuli. Based on this observation, it was hypothesized that these parallel descending circuits shape responses to diverse stressors and are altered in clinical depression and comorbid anxiety disorders. To explore this possibility, the experiments in this dissertation used two recombinant PRV strains to trace polysynaptic premotor and presympathetic pathways innervating sympathectomized skeletal muscle and adrenal gland, respectively, in two rat models with heritable differences in emotionality and stress reactivity: the Wistar-Kyoto (WKY) rat and the selectively bred Low Novelty Responder (bLR) rat. During our initial neuroanatomical investigations in the PVN, we observed that both WKY and bLR rats displayed significant decreases in the quantity of PVN neurons with premotor projections to skeletal muscle compared to their respective control strains. Labeling of neurons with presympathetic projections to adrenal gland or dual-labeled polysynaptic projections to both motor and sympathetic targets was not altered in either model. Our subsequent neuroanatomical studies focused on comparing premotor efferent projections from LC and PAG. In LC, fewer premotor efferent projections to skeletal muscle were observed in both models. There were also reductions in the number of premotor efferents in the four subdivisions of the PAG. WKY rats had significantly fewer premotor projections in the dorsomedial (DMPAG), lateral (LPAG), and ventrolateral (VLPAG) subdivisions, while bLR rats had significantly fewer premotor efferents in dorsolateral (DL)PAG. The final experiments in this dissertation sought to determine whether one potential therapeutic intervention, environmental enrichment during late childhood and adolescence, can improve emotional behavior disturbances and reverse premotor circuit alterations in bLR rats. Rearing young bLR rats in conditions with increased environmental complexity partially but incompletely improved aspects of depression- and anxiety-relevant behaviors and their corresponding PVN premotor circuit abnormalities. Cumulatively, these findings highlight somatomotor circuits in several brain structures involved in responses to stress and emotional stimuli that could be implicated in mediating motor-related impairments in clinical depression.
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    A Role for Microglia Activation in Modulating Behavior in a Variable Stress Model for Depression
    Tsyglakova, Mariya (Virginia Tech, 2022-06-23)
    Major Depressive Disorder is a common mood disorder, affecting more than 300 million people worldwide. Stress, being a potent trigger for various mood disorders, including depression, affects both the peripheral and central immune systems. Microglia are the resident immune cells in the brain and changes in their morphology and state of activation in response to stress have been reported in a number of brain regions, however most studies examined only male subjects. In our studies we investigated morphological changes in microglia in the nucleus accumbens and subregions of the hippocampus in both male and female mice following variable stress. Our findings demonstrate that following 6 days of variable stress female microglia acquire a more activated phenotype compared to microglia in males. These sex specific effects in microglia activation were also observed in the nucleus accumbes, but not the dentate gyrus after 28 days of stress. Utilizing a number of pharmacological agents, we further investigated whether changes in the inflammatory states of microglia modulate behavior in female mice in a variable stress model for depression. We found that rosiglitazone, peroxisome proliferator activated receptor gamma PPAR) agonist, which causes microglial shift to an anti-inflammatory state, conferred social resilience in female mice after 6 days of variable stress. We further demonstrated that blocking pro-inflammatory activation of microglia with minocycline, a tetracyclic antibiotic, did not prevent the stress effects on behavior. Surprisingly, prior pro-inflammatory activation of microglia with lipopolysaccharide (LPS), an endotoxin from gram-negative bacteria, was protective against subsequent variable stress. Finally, I describe the impact of systemic application of these drugs on microglia morphology and activation state, and cytokine levels in the nucleus accumbens of female mice. Taken together this body of work contributes to a growing number of studies demonstrating neuro-immune mechanisms associated with depression.
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    Sex and region-specific effects of variable stress on microglia morphology
    Tsyglakovaa, Mariya; Huskey, Alisa M.; Hurst, Emily H.; Telep, Natalie M.; Wilding, Mary C.; Babington, Meghan E.; Rainville, Jennifer R.; Hodes, Georgia E. (Elsevier, 2021-11-06)
    Major Depressive Disorder (MDD) is a common and debilitating mood disorder that is more prevalent in women than men. In humans, PET imaging of microglia activation is currently being explored as a potential biomarker of MDD and suicidal ideation. Stress is a trigger for many mood disorders, including MDD. Microglial changes in morphology and activation state in response to stress has been reported in various brain regions, but most studies only examined male subjects. Here we report changes in microglia morphology in the nucleus accumbens (NAc) and subregions of the hippocampus (HPC) in both male and female mice following variable stress of 6 or 28 days in duration. Our data demonstrate that after 6 days of stress, microglia in the female NAc and dentate gyrus have a reduction in homeostatic associated morphology and an increase in primed microglia. After 28 days some of these sex specific stress effects were still present in microglia within the NAc but not the dentate gyrus. There were no effects of stress in either sex at either timepoint in CA1. In female mice, anti-inflammatory activation of microglia using rosiglitazone promoted sociability behavior after 6 days of stress. Furthermore, both drug and stress have impact on microglia morphology and activation state in the NAc. These data suggest that microglia morphology and activation state are altered by 6 days of variable stress in a region-specific manner and may contribute to, or potentially compensate for, the onset of stress susceptibility rather than impacting long term exposure to stress.
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    Sex as a biological variable in stress and mood disorder research
    Hodes, Georgia E.; Kropp, Dawson R. (Springer Nature, 2023-07)
    In 2016, changes were mandated for basic research, including using sex as a biological variable. This policy change was due to the lack of research performed in female animals. This resulted in a mismatch between the sex of the subjects being used for drug development and the sex of the participants in subsequent clinical trials hampering the translational success of novel therapeutics, especially treatments for mood disorders. While it is now clear that sex differences exist, the field needs to move to the next frontier in sex-difference research. We need to start exploring why and how these sex differences exist. What are their functions? How do we harness this information to develop novel sex-specific treatments for mental illness? This Review will address what we have learned from using sex as a biological variable and how we can utilize these data to better understand and treat sex-based disparities in mental health.
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    Sex differences in depression: An immunological perspective
    Kropp, Dawson R.; Hodes, Georgia E. (Pergamon-Elsevier, 2023-05)
    Depression is a heterogenous disorder with symptoms that present differently across individuals. In a subset of people depression is associated with alterations of the immune system that may contribute to disorder onset and symptomology. Women are twice as likely to develop depression and on average have a more sensitive adaptive and innate immune system when compared to men. Sex differences in pattern recognition receptors (PRRs), release of damage-associated molecular patterns (DAMPs), cell populations, and circulating cytokines play a critical role in inflammation onset. Sex differences in innate and adaptive immunity change the response of and repair to damage caused by dangerous pathogens or molecules in the body. This article reviews the evidence for sex specific immune responses that contribute to the sex differences in symptoms of depression that may account for the higher rate of depression in women.
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    Sex linked behavioral and hippocampal transcriptomic changes in mice with cell-type specific Egr1 loss
    Swilley, Cody; Lin, Yu; Zheng, Yuze; Xu, Xiguang; Liu, Min; Jarome, Timothy J.; Hodes, Georgia E.; Xie, Hehuang (Frontiers, 2023-10-19)
    The transcription factor EGR1 is instrumental in numerous neurological processes, encompassing learning and memory as well as the reaction to stress. Egr1 complete knockout mice demonstrate decreased depressive or anxiety-like behavior and impaired performance in spatial learning and memory. Nevertheless, the specific functions of Egr1 in distinct cell types have been largely underexplored. In this study, we cataloged the behavioral and transcriptomic character of Nestin-Cre mediated Egr1 conditional knockout (Egr1cKO) mice together with their controls. Although the conditional knockout did not change nociceptive or anxiety responses, it triggered changes in female exploratory activity during anxiety testing. Hippocampus-dependent spatial learning in the object location task was unaffected, but female Egr1cKO mice did exhibit poorer retention during testing on a contextual fear conditioning task compared to males. RNA-seq data analyses revealed that the presence of the floxed Egr1 cassette or Nestin-Cre driver alone exerts a subtle influence on hippocampal gene expression. The sex-related differences were amplified in Nestin-Cre mediated Egr1 conditional knockout mice and female mice are more sensitive to the loss of Egr1 gene. Differentially expressed genes resulted from the loss of Egr1 in neuronal cell lineage were significantly associated with the regulation of Wnt signaling pathway, extracellular matrix, and axon guidance. Altogether, our results demonstrate that Nestin-Cre and the loss of Egr1 in neuronal cell lineage have distinct impacts on hippocampal gene expression in a sex-specific manner.
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    Sex, stress, and epigenetics: regulation of behavior in animal models of mood disorders
    Hodes, Georgia E. (BMC, 2013)
    Women have a higher incidence of stress related disorders including depression and generalized anxiety disorder, and epigenetic mechanisms likely contribute to this sex difference. Evidence from preclinical research suggests that epigenetic mechanisms are responsible for both sexual dimorphism of brain regions and sensitivity of the stress response. Epigenetic modifications such as DNA methylation and histone modifications can occur transgenerationally, developmentally, or in response to environmental stimuli such as stress exposure. This review will provide an overview of the various forms of epigenetic modifications observed in the central nervous system and will explain how these mechanisms contribute to a sexually dimorphic brain. It will also discuss the ways in which epigenetic alterations coincide with, and functionally contribute to, the behavioral response to stress across the lifespan. Ultimately, this review will focus on novel research utilizing animal models to investigate sex differences in epigenetic mechanisms that influence susceptibility to stress. Exploration of this relationship reveals epigenetic mechanisms with the potential to explain sexual dimorphism in the occurrence of stress related disorders.