Abstract Osteosarcoma (OS) is an aggressive pediatric solid tumor that is difficult to treat with established therapies. We mined the DepMap data in 13 OS cell line this data to identify enriched dependencies whose knockout (KO) leads to selective anti-viability in OS. We observed that SMARCAL1 as a selective dependency in OS (p<0.0001; effect size = -0.275). We reasoned that SMARCAL1 is important given the genomic instability of OS and SMARCAL1’s known role in replication stress. We first validated screen findings by CRISPR KO in OS lines in vitro. This demonstrated selective antiviability effect of SMARCAL1 KO in dependent OS lines. To orthogonally validate SMARCAL1 dependency, we deployed a dTAG system that utilizes a hetero-bifunctional small molecule targeting the tagged protein for degradation by an E3 ubiquitin ligase. We observed significant antiviability of dependent OS after SMARCAL1 degradation. In parallel, in order to ascertain SMARCAL1’s relevance as a target in OS in vivo, we performed a pooled barcoded CRISPR screen (n=1,626 guides) against pre-selected OS dependencies in an OS cell line xenograft in NSG mice. After sequencing of tumor gDNA, we identified SMARCAL1 as a top hit, suggesting its importance in OS in vivo. We next investigated biomarkers of SMARCAL1 dependency. A role for SMARCAL1 has been described in alternative lengthening of telomeres (ALT). With this knowledge, we asked whether ALT+ OS lines are enriched for SMARCAL1 dependence. We found a correlation between ALT+ OS and SMARCAL1 dependence in our CRISPR screens. We then asked if this extends to other ALT+ tumors. Neuroblastoma (NB), the most common extracranial pediatric solid tumor, is ALT-enriched. When we looked specifically at NB, we observed that SMARCAL1 was the most enriched dependency in ALT+ NB compared with other NB lines (p<0.0001; effect size = -0.785). When then performed KO of SMARCAL1 in 2 ALT+ ATRX altered NB lines and one ALT+ ATRX wildtype (WT) NB line. We found that SMARCAL1 KO led to antiviability in ATRX altered ALT+ cell lines, while the ALT+, ATRX WT cell line was unaffected. This suggests that dependency on SMARCAL1 is specific to ATRX/DAXX alteration, rather than only ALT. In order to confirm synthetic lethality between ATRX and SMARCAL1, we next utilized a human OS line which has biallelic inactivation of SMARCAL1. We infected this line with our SMARCAL1 dTAG, leading to constitutive overexpression of tagged SMARCAL1, and then performed ATRX CRISPR KO. We observed that SMARCAL1 overexpression rescued the antiviability effect of ATRX KO, and that this could be reversed by degradation of exogenous SMARCAL1, suggesting that ATRX and SMARCAL1 can compensate for one another. Taken together, these findings demonstrate that SMARCAL1 is a selective dependency that is engendered by the loss of WT ATRX/DAXX in OS and NB and that SMARCAL1 is playing a critical role in mediating ALT. Studies are ongoing to determine the mechanism of SMARCAL1’s activity and potential for targeting this enzyme for therapeutic benefit. Citation Format: Monika Wierdl, Jerrel L. Catlett, Nicole Ocasio-Martinez, John D. Johnson Jr, Amy Herman, Neekesh V. Dharia, Gabriela Alexe, E. Alejandro Sweet-Cordero, Emily Bernstein, Kimberly Stegmaier, Lillian M. Guenther. SMARCAL1 is a selective dependency and a novel synthetic lethal target in ATRX/DAXX mutant ALT+ osteosarcoma and neuroblastoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Damage Repair: From Basic Science to Future Clinical Application; 2024 Jan 9-11; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2024;84(1 Suppl):Abstract nr PR004.

Tyrosine hydroxylase (TH) catalyzes the rate-limiting step in the catecholamine (CA) biosynthesis pathway, making TH a molecular target for controlling CA production, specifically dopamine. Dysregulation of dopamine is correlated with neurological diseases such as Parkinson's disease (PD) and post-traumatic stress disorder (PTSD), among others. Previously, we showed that a 49-nucleotide guanine (G)-rich sequence within the human TH promoter adopts two different sets of G-quadruplex (GQ) structures (5'GQ and 3'GQ), where the 5'GQ uses G-stretches I, II, IV, and VI in TH49, which enIV, VI, and VII, which represses transcription. Herein, we demonstrated targeted switching of these GQs to their active state using rationally designed DNA GQ Clips (5'GQ and 3'GQ Clips) to modulate endogenous TH gene expression and dopamine production. As a translational approach, we synthesized a targeted nanoparticle delivery system to effectively deliver the 5'GQ Clip in vivo. We believe this strategy could potentially be an improved approach for controlling dopamine production in a multitude of neurological disorders, including PD.

Circadian rhythms play a prominent role in psychiatric health with disruption in rhythms associated with poor mental health. Corticosterone (CORT) is an important hormone in entraining the biological rhythms of many cells throughout the body and coordinating peripheral rhythms with the central master clock. Here, we tested the hypothesis that excess CORT during the circadian trough would lead to a flattening of period genes (Per1 and Per2) rhythms in limbic brain areas, and thus impact emotional behaviors. Male rats were injected daily with 2.5 mg/kg CORT or vehicle for 21 days at either ZT0 or ZT12 and sucrose preference, open field, and forced swim behaviors measured during the dark phase of the light cycle. After three weeks of injections, a reduction in sucrose preference was observed in animals injected with CORT at ZT0 and the reduction significantly correlated with reductions in Per2 mRNA expression in the central amygdala (CeA) and bed nucleus of the stria terminalis (BNST). No changes in behavior or period gene expression were observed in animals injected with CORT at ZT12. DsiRNA was used to directly reduce Per2 levels in either the CeA or BNST and behavior was assessed. Despite reductions in Per2 expression in the CeA, no behavioral changes were observed. In contrast, a reduction in Per2 expression in the BNST was sufficient to reduce sucrose preference. The results demonstrate that CORT significantly contributes to the circadian expression of Period genes in certain limbic brain areas and disruption in diurnal CORT or Per2 expression can lead to impaired emotional behavioral responses.

Following a stressful event, the hypothalamus-pituitary-adrenal axis mediates the release of the stress hormone cortisol (corticosterone in rodents; CORT). Elevated CORT binds to glucocorticoid receptors to mediate physiological responses including facilitating memory formation. Previous work from our laboratory demonstrated that male rats exposed to chronic stress demonstrate enhanced contextual fear memories and sensitized CORT responses to subsequent stress exposure; however, this is unknown in female rats. The experiments here tested whether chronic stress enhances fear memory formation in female rats and whether the sensitized CORT response in chronic stress rats contributes to their enhanced fear memory. Studies first examined CORT responses to contextual fear conditioning in male and female rats and examined whether chronic stress enhanced the formation of contextual fear memories 24 h later. Studies then used metyrapone, a CORT synthesis inhibitor, to investigate whether blockade of plasma CORT would eliminate the chronic stress-induced enhancement in contextual fear memory. Results show that female rats have greater CORT responses than males, and chronic stress sensitizes the CORT response to fear conditioning in both sexes. However, female rats do not show enhanced contextual fear memory following chronic stress. Chronically stressed male rats show greater memory acquisition and show greater contextual fear memory 24 h later following fear conditioning. Metyrapone dampens contextual fear memory in all rats but does not eliminate the enhancement in freezing behavior in chronic stress rats. Collectively, these studies indicate sensitized CORT responses in chronically stressed rats is likely not the mechanism by which chronic stress facilitates memory formation.

Abstract There is growing evidence that stress-induced brain cytokines are important in the etiology of depression and anxiety. Here, we review how the neuroendocrine responses to psychological stressors affect the immediate and long-term regulation of inflammatory cytokines within the brain and highlight how the regulation changes across time with repeated stress exposure. In doing so, we report on the percentage of studies in the literature that observed increases in either IL-1β, TNF-α, or IL-6 within the hypothalamus, hippocampus, or prefrontal cortex after either acute or chronic stress exposure. The key takeaway is that catecholamines and glucocorticoids play critical roles in the regulation of brain cytokines after psychological stress exposure. Central catecholamines stimulate the release of IL-1β from microglia, which is a key factor in the further activation of microglia and recruitment of monocytes into the brain. Meanwhile, the acute elevation of glucocorticoids inhibits the production of brain cytokines via two mechanisms: the suppression of noradrenergic locus coeruleus neurons and inhibition of the NFκB signaling pathway. However, glucocorticoids and peripheral catecholamines facilitate inflammatory responses to future stimuli by stimulating monocytes to leave the bone marrow, downregulating inhibitory receptors on microglia, and priming inflammatory responses mediated by peripheral monocytes or macrophages. The activation of microglia and the elevation of peripheral glucocorticoid and catecholamine levels are both necessary during times of stress exposure for the development of psychopathologies.

Elevations in brain interleukin-1 beta (IL-1β) during chronic stress exposure have been implicated in behavioral and cognitive impairments associated with depression and anxiety. Two critical regulators of brain IL-1β production during times of stress are glucocorticoids and catecholamines. These hormones work in opposition to one another to inhibit (via glucocorticoid receptors) or stimulate (via beta-adrenergic receptors: β-AR) IL-1β production. While chronic stress often heightens both corticosterone and catecholamine levels, it remains unknown as to how chronic stress may affect the "yin-yang" balance between adrenergic stimulation and glucocorticoid suppression of brain IL-1β. To investigate this further, male and female rats underwent 4 days of stress exposure or served as non-stressed controls. On day 5, animals were administered propranolol (β-AR antagonist), metyrapone (a glucocorticoid synthesis inhibitor), vehicle, or both drugs and brain IL-1β mRNA was measured by rtPCR in limbic brain areas. In males, administration of propranolol had no effect on IL-1β expression in non-stressed controls but significantly reduced IL-1β in the hippocampus and amygdala of chronically stressed animals. In females, propranolol significantly reduced IL-1β in the amygdala and hypothalamus of both control and stressed rats. In male rats, metyrapone treatment significantly increased IL-1β mRNA regardless of stress treatment in all brain areas, while in female rats metyrapone only increased IL-1β in the hypothalamus. Interestingly, propranolol treatment blocked the metyrapone-induced increase in brain IL-1β indicating the increase in brain IL-1β following metyrapone treatment was due to increase β-AR activation. Additional studies revealed that metyrapone significantly increases norepinephrine turnover in the hypothalamus and medial prefrontal cortex in male rats and that microglia appear to be the cell type contributing to the production of IL-1β. Overall, data reveal that stress exposure in male rats affects the regulation of brain IL-1β by the norepinephrine-β-AR pathway, while stress had no effect in the regulation of brain IL-1β in female rats.

Impaired fear extinction, combined with the likelihood of fear relapse after exposure therapy, contributes to the persistence of many trauma-related disorders such as anxiety and post-traumatic stress disorder. Identifying mechanisms to aid fear extinction and reduce relapse could provide novel strategies for augmentation of exposure therapy. Exercise can enhance learning and memory and augment fear extinction of traumatic memories in humans and rodents. One factor that could contribute to enhanced fear extinction following exercise is the mammalian target of rapamycin (mTOR). mTOR is a translation regulator involved in synaptic plasticity and is sensitive to many exercise signals such as monoamines, growth factors, and cellular metabolism. Further, mTOR signaling is increased after chronic exercise in brain regions involved in learning and emotional behavior. Therefore, mTOR is a compelling potential facilitator of the memory-enhancing and overall beneficial effects of exercise on mental health. The goal of the current study is to test the hypothesis that mTOR signaling is necessary for the enhancement of fear extinction produced by acute, voluntary exercise. We observed that intracerebral-ventricular administration of the mTOR inhibitor rapamycin reduced immunoreactivity of phosphorylated S6, a downstream target of mTOR, in brain regions involved in fear extinction and eliminated the enhancement of fear extinction memory produced by acute exercise, without reducing voluntary exercise behavior or altering fear extinction in sedentary rats. These results suggest that mTOR signaling contributes to exercise-augmentation of fear extinction.

Exposure to chronic stress often elevates basal circulating glucocorticoids during the circadian nadir and leads to exaggerated glucocorticoid production following exposure to subsequent stressors. While glucocorticoid production is primarily mediated by the hypothalamic-pituitary-adrenal (HPA) axis, there is evidence that the sympathetic nervous system can affect diurnal glucocorticoid production by direct actions at the adrenal gland. Experiments here were designed to examine the role of the HPA and sympathetic nervous system in enhancing corticosterone production following chronic stress. Rats were exposed to a four-day stress paradigm or control conditions then exposed to acute restraint stress on the fifth day to examine corticosterone and ACTH responses. Repeated stressor exposure resulted in a small increase in corticosterone, but not ACTH, during the circadian nadir, and also resulted in exaggerated corticosterone production 5, 10, and 20 min following restraint stress. While circulating ACTH levels increased after 5 min of restraint, levels were not greater in chronic stress animals compared to controls until following 20 min. Administration of astressin (a CRH antagonist) prior to restraint stress significantly reduced ACTH responses but did not prevent the sensitized corticosterone response in chronic stress animals. In contrast, administration of chlorisondamine (a ganglionic blocker) returned basal corticosterone levels in chronic stress animals to normal levels and reduced early corticosterone production following restraint (up to 10 min) but did not block the exaggerated corticosterone response in chronic stress animals at 20 min. These data indicate that increased sympathetic nervous system tone contributes to elevated basal and rapid glucocorticoid production following chronic stress, but HPA responses likely mediate peak corticosterone responses to stressors of longer duration. (C) 2016 Published by Elsevier Ltd.

There is growing evidence that metabolic stressors increase an organism's risk of depression. Chronic mild stress is a popular animal model of depression and several serendipitous findings have suggested that food deprivation prior to sucrose testing in this model is necessary to observe anhedonic behaviors. Here, we directly tested this hypothesis by exposing animals to chronic mild stress and used an overnight 2-bottle sucrose test (food ad libitum) on Day 5 and 10, then food and water deprive animals overnight and tested their sucrose consumption and preference in a 1-hr sucrose test the following morning. Approximately 65% of stressed animals consumed sucrose and showed a sucrose preference similar to nonstressed controls in an overnight sucrose test, and 35% showed a decrease in sucrose intake and preference. Following overnight food and water deprivation the previously "resilient" animals showed a significant decrease in sucrose preference and greatly reduced sucrose intake. In addition, we evaluated whether the onset of anhedonia following food and water deprivation corresponds to alterations in corticosterone, epinephrine, circulating glucose, or interleukin-1 beta (IL-1β) expression in limbic brain areas. Although all stressed animals showed adrenal hypertrophy and elevated circulating epinephrine, only stressed animals that were food deprived were hypoglycemic compared with food-deprived controls. Additionally, food and water deprivation significantly increased hippocampus IL-1β while food and water deprivation only increased hypothalamus IL-1β in stress-susceptible animals. These data demonstrate that metabolic stress of food and water deprivation interacts with chronic stressor exposure to induce physiological and anhedonic responses.

Memory formation is promoted by stress via the release of norepinephrine and stimulation of beta-adrenergic receptors (β-ARs). Previous data demonstrate that repeated stressor exposure increases norepinephrine turnover and β-AR signaling within the amygdala, which led to the hypothesis that some stress-induced behavioral changes are likely due to facilitated associative learning. To test this, Fischer rats were exposed to chronic mild stress for four days. On day 5, subjects (including non-stressed controls) were injected with the beta-blocker propranolol or vehicle prior to conditioning in an operant box (animals receive two mild foot shocks) or passive avoidance apparatus (animals received a foot shock upon entry into the dark chamber). Twenty-four hours later, subjects were returned to the operant box for measurement of freezing or returned to the passive avoidance apparatus for measurement of latency to enter the dark chamber. Subjects were also tested in an open field to assess context-independent anxiety-like behavior. Animals exposed to chronic stress showed significantly more freezing behavior in the operant box than did controls, and this exaggerated freezing was blocked by propranolol during the conditioning trial. There was no effect of stress on behavior in the open field. Unexpectedly, retention latency was significantly reduced in subjects exposed to chronic stress. These results indicate that chronic exposure to stress results in complex behavioral changes. While repeated stress appears to enhance the formation of fearful memories, it also results in behavioral responses that resemble impulsive behaviors that result in poor decision-making.

1. INTRODUCTION Recent studies have highlighted the importance of improving education for a new generation of students in data-driven information systems (IS) educational areas (Chen, Chiang, and Storey, 2012; Chiang, Goes, and Stohr, 2012). Among courses offered by IS faculty, database management is the most consistently offered course among the IS 2010 curriculum model (IS 2010.2) with approximately 97% of programs including this class (Bell, Mills, and Fadel, 2013). Demand for graduates with expertise in Structured Query Language (SQL) and database management remains strong. The growth of SQL is often attributed to its role as a standard data access method for big data (Soat, 2014). Both Computer Weekly and ZDNet find SQL as the software skill most in demand (Flinders, 2011; Lomas, 2011). Student's graduating with a background in database often find themselves in a unique situation when interviewing for a professional IS position. Many interviews not only require students to be proficient in database nomenclature, but are often required to write structured query language code to solve business problems as part of the interview (Kadlec, 2008). Many professors have recognized the importance of writing code by organizing coding labs for applied practice. Unfortunately, database education often includes lectures and slides with lots of terminology as the only instructional approach to transfer this knowledge to the learner. As a result, students are unprepared to solve complex problems in industry including the rigorous interviewing process (Schank, 2002; Tang, Lee, and Koh, 2000). Strategically bridging new information to an individual's prior knowledge is documented in the literature as a way to improve the learning process (Catrambone and Holyoak, 1989; Gentner and Holyoak, 1997). Analogy problem construction represents an instructional strategy used to link prior knowledge to new knowledge (Togo, 2002). Analogy problem construction involves students creating their own analogous problems to better understand and retain new knowledge (Bernardo, 2001). The focus of this technique is to tap into a learner's existing knowledge structures and leverage this prior knowledge to new knowledge. The use of analogies in learning are credited as among the most effective method of solidifying abstract concepts to better understanding and retention of new knowledge (Dincer, 2011). As a result, linking new knowledge to personal knowledge contribute to meaningful, active, and effective learning (Seyihoglu and Ozgurbuz, 2015). Prior research also suggests learning styles potentially have an impact on user learning (Bostrom, Olfman, and Sein, 1990). The Felder and Soloman Index of Learning Styles instrument was specifically created to identify learning styles in a classroom setting (De Vita, 2001). The instrument organizes competing learning styles, which include active versus reflective, sensing versus intuitive, visual versus verbal, and sequential versus global preferences. Felder (1993) argues sound instruction should incorporate a variety of teaching styles addressing each side of the learning dimensions at least part of the time. Although research related to analogy problem construction and learning styles are examined in some detail (Cellucci et al., 2011; Togo, 2002; Zheng et al., 2008), there is a dearth of research in information systems education (Cegielski, Hazen, and Rainer, 2011). Felder and Silverman (1988) argue students absorb concepts more quickly when instructional strategies are consistent with the student's learning style. A recent information systems study supports the value of matching activities with learning styles when possible. The study examined learning styles and object-oriented computer programming and found performance increases when the instructional strategies closely matched the student's learning style (Cegielski, Hazen, and Rainer, 2011). The authors conclude the research "serve[s] as a foundation from which to launch a detailed research agenda in the area of learning styles within the IS educational domain" (Cegielski, Hazen, and Rainer, 2011, p. …

Case-based research has been an important approach to evaluate models of tax law. One area of tax law that has been controversial for decades is the worker classification issue. This study uses artificial intelligence methods to construct a model to help resolve this controversy. Another purpose is to evaluate the performance of neural networks in case-based research. Models were developed using step-wise multiple regression, step-wise logistic regression, discriminant analysis and an artificial neural network (ANN).The ANN model is shown to outperform these other models with its predictive ability. This result points to the importance of ANN in case-based research. Worker classification for federal tax purposes (both income and employment tax) has been a controversial area for decades. Distinguishing between an employee and independent contractor may be difficult, yet necessary in order to comply with tax laws and regulatory agency requirements. Previous studies concerning this problem fail to account for possible nonlinear and cross product effects that are expected in the data. The purpose of this study is to use artificial intelligence methods to construct a model that will help resolve this controversy and to demonstrate the effectiveness of these methods. Specifically artificial neural networks (ANN), which account for possible cross product effects and provide a flexible nonlinear functional form, are used. Since 1988, the Internal Revenue Service (IRS) has conducted a high priority campaign to address worker classification issues, with revenue officers performing special audits to uncover misclassification. By 1996, this aggressive enforcement program resulted in 12,983 employment tax audits and the reclassification of 527,000 workers in Vizcaino v. Microsoft Corp. 97 F3d 1187, 1202 (CA-9, 1996). As Microsoft learned, the consequences of reclassification can be more pervasive than the amount of assessed taxes, plus any penalty and interest. After the IRS reclassified Microsoft's "freelancers" from independent contractors to employees, several such 'freelancers' sought various employee benefits from Microsoft. Circuit Judge Trott (in his dissent) laments that the IRS's tough enforcement policy not only collects more money for the government, but it has unforeseen consequences of forcing employers to

Exaggerated pro-inflammatory cytokine production by primed microglia is thought to mediate pathology during stress, aging, and neurodegeneration. Recently, it was demonstrated that beta-adrenergic receptor (β-AR) antagonism prevents priming of microglia in mice exposed to chronic stress. To determine if β-AR stimulation is sufficient to prime microglia, rats were intra-cerebroventricularly administered isoproterenol (β-AR agonist) or vehicle and 24 h later hippocampal microglia were placed in culture with media or LPS. Prior isoproterenol treatment significantly enhanced IL-1β and IL-6, but not TNF-α production following LPS stimulation. These data suggest that central β-AR stimulation is sufficient to prime microglia cytokine responses.

Major depression is a debilitating disorder, characterized by feelings of worthlessness, persistent sadness and lack of motivation. Depression is also recognized to be a chronic, recurrent disorder, and each depressive episode increases an individual's susceptibility to future occurrences. The current study aimed to develop an animal model of recurrent depression in order to examine possible biological mechanisms responsible for this increased susceptibility. We hypothesized that animals with a prior depressive episode would be sensitive to future stressors, causing the animals to display depressive-like behaviors more rapidly or to a greater extent. Fisher rats (n = 15) were exposed to chronic mild stress for 35 days or remained in their home cage as controls. During the initial stress, animals showed a slow decrease in sucrose consumption. Following the 35 days, animals went through a 20 day recovery phase where no stressors were present and animals showed a steady increase in sucrose consumption back to baseline levels. At this time animals were re-exposed to the chronic mild stress for 15 days. A rapid decline in sucrose consumption was observed. Linear regression lines were calculated for each animal's sucrose consumption during the first and second stressor exposure and a paired t-test of the slope of each line revealed re-exposure to stress resulted in a significantly more rapid decline in sucrose consumption compared to that observed during the initial stressor exposure.

Evacuation planning for private-sector organizations is an important consideration given the continuing occurrence of both natural and human-caused disasters that inordinately affect them. Unfortunately, the traditional management approach that is focused on fire drills presents several practical challenges at the scale required for many organizations but especially those responsible for national critical infrastructure assets such as airports and sports arenas. In this research we developed Exitus, a comprehensive decision support system that may be used to simulate large-scale evacuations of such structures. The system is unique because it considers individuals with disabilities explicitly in terms of physical and psychological attributes. It is also capable of classifying the environment in terms of accessibility characteristics encompassing various conditions that have been shown to have a disproportionate effect upon the behavior of individuals with disabilities during an emergency. The system was applied to three unique test beds: a multi-story office building, an international airport, and a major sports arena. Several simulation experiments revealed specific areas of concern for both building managers and management practice in general. In particular, we were able to show (a) how long evacuations of heterogeneous populations may be expected to last, (b) who the most vulnerable groups of people are, (c) the risk engendered from particular design features for individuals with disabilities, and (d) the potential benefits from adopting alternate evacuation strategies, among others. Considered together, the findings provide a useful foundation for the development of best practices and policies addressing the evacuation concerns surrounding heterogeneous populations in large, complex environments. Ultimately, a capabilities-based approach featuring both tactical and strategic planning with an eye toward the unique problems presented by individuals with disabilities is recommended.

Activation of the in vivo stress response can facilitate antibacterial host defenses. One possible mechanism for this effect is stress-induced release of heat shock protein 72 (Hsp72) into the extracellular environment. Hsp72 is a ubiquitous cellular protein that is up-regulated in response to cellular stress, and modulates various aspects of immune function including macrophage inflammatory/bactericidal responses and T-cell function when found in the extracellular environment. The current study tested the hypothesis that in vivo extracellular Hsp72 (eHsp72) at the site of inflammation contributes to stress-induced restricted development of bacteria, and facilitated recovery from bacteria-induced inflammation, and that this effect is independent of alpha beta (αβ) T cells. Male F344 rats were exposed to either inescapable electrical tail-shocks or no stress, and subcutaneously injected with Escherichia coli (ATCC 15746). The role of eHsp72 was investigated by Hsp72-immunoneutralization at the inflammatory site. The potential contribution of T cells was examined by testing male athymic (rnu/rnu) nude rats lacking mature αβ T cells and heterozygous thymic intact control (rnu/+) rats. The results were that stressor exposure increased plasma concentrations of eHsp72 and facilitated recovery from bacterial inflammation. Immunoneutralization of eHsp72 at the inflammatory site attenuated this effect. Stressor exposure impacted bacterial inflammation and eHsp72 equally in both athymic and intact control rats. These results support the hypothesis that eHsp72 at the site of inflammation, and not αβ T cells, contributes to the effect of stressor exposure on subcutaneous bacterial inflammation.

There is high comorbidity between metabolic syndrome and depression. Here we examine if acute metabolic stressors, either overnight food deprivation or 2-deoxyglucose injection (250 mg/kg), would potentiate anhedonia and IL-1β expression following chronic mild stress. To test this we measured sucrose preference and IL-1β in both control and stressed animals with or without a metabolic stressor. Our results found that chronic mild stress induced depressive behaviors in only a portion of the animals (stress-susceptible), while other animals continued to have high levels of sucrose preference that were similar to controls (stress-resistant). Exposure to food deprivation prior to testing did not affect sucrose preference in control animal nor did it alter the reduced sucrose preference in stress-susceptible animals, but overnight food deprivation caused a significant decrease in sucrose preference in stress-resistant animals. 2-Deoxyglucose injection caused a significant reduction in both control and stressed animals' preference for sucrose. Additionally, there was no effect of chronic stress on IL-1β levels, but food deprivation caused an increase of IL-1β in the hippocampus and brainstem; decreased levels in the prefrontal cortex; and a potential interaction between stress and food deprivation in the hypothalamus (p = 0.10). Our results indicate that metabolic stressors likely interact with psychological stressors to promote depression-like responses and that more severe metabolic stressors may themselves induce anhedonic responses. Furthermore, metabolic stressors affect regional levels of brain cytokines.

It has been proposed that increased brain cytokines during repeated stressor exposure can contribute to neuropathological changes that lead to the onset of depression. Previous studies demonstrate that norepinephrine acting via beta-adrenergic receptors (β-ARs) mediate brain IL-1 production during acute stressor exposure. The aim of the current studies was to examine how the regulation of brain cytokines by adrenergic signaling might change following repeated stressor exposure. Fischer rats were exposed to four days of chronic mild stress and 24 h after the last stressors β-AR expression, norepinephrine turnover, and β-AR-mediated induction of brain IL-1 were measured in limbic areas (e.g. hypothalamus, hippocampus, amygdala, and prefrontal cortex) and brainstem. Repeated stressor exposure resulted in decreases in β-AR expression (Bmax) measured by saturation binding curves in many limbic brain areas, while an increase was observed in the brainstem. This coincided with significant increases in norepinephrine turnover in the prefrontal cortex, hypothalamus, and amygdala, a significant increase in norepinephrine turnover was not observed in the hippocampus or brainstem. Stress increased overall IL-1 production in the amygdala (both basal and stimulated). While stress did not affect basal IL-1 levels in any other brain area, central administration of isoproterenol (a β-AR agonist) augmented IL-1 production in the hypothalamus of stressed animals. These data indicate that repeated stressor exposure results in brain area specific enhancements in β-AR-mediated IL-1 production and extends current knowledge of stress-induced enhancement of brain cytokine beyond sensitized response to immunological stimuli.