Knockout of the circadian gene, Per2, disrupts corticosterone secretion and results in depressive-like behaviors and deficits in startle responses.

BACKGROUND: The Period Circadian Regulator 2 (Per2) gene is important for the modulation of circadian rhythms that influence biological processes. Circadian control of the hypothalamus-pituitary-adrenal (HPA) axis is critical for regulation of hormones involved in the stress response. Dysregulation of the HPA axis is associated with neuropsychiatric disorders. Therefore, it is important to understand how disruption of the circadian rhythm alters the HPA axis. One way to address this question is to delete a gene involved in regulating a central circadian gene such as Per2 in an animal model and to determine how this deletion may affect the HPA axis and behaviors that are altered when the HPA axis is dysregulated. To study this, corticosterone (CORT) levels were measured through the transition from light (inactive phase) to dark (active phase). Additionally, CORT levels as well as pituitary and adrenal mRNA expression were measured following a mild restraint stress. Mice were tested for depressive-like behaviors (forced swim test (FST)), acoustic startle response (ASR), and pre-pulse inhibition (PPI). RESULTS: The present results showed that Per2 knockout impacted CORT levels, mRNA expression, depressive-like behaviors, ASR and PPI. Unlike wild-type (WT) mice, Per2 knockout (Per2) mice showed no diurnal rise in CORT levels at the onset of the dark cycle. Per2-/- mice had enhanced CORT levels and adrenal melanocortin receptor 2 (Mc2R) mRNA expression following restraint. There were no changes in expression of any other pituitary or adrenal gene. In the FST, Per2-/- mice spent more time floating (less time struggling) than WT mice, suggesting increased depressive-like behaviors. Per2-/- mice had deficits in ASR and PPI startle responses compared to WT mice. CONCLUSIONS: In summary, these findings showed that disruption of the circadian system via Per2 gene deletion dysregulated the HPA stress axis and is subsequently correlated with increased depressive-like behaviors and deficits in startle response.

Sex differences in the hypothalamic-pituitary-adrenal axis response following a single or multiple days of sleep restriction.

One in three adults reports experiencing inadequate or disrupted sleep throughout the night, with the incidence being higher in women than in men. Disturbances in nightly sleep result in physiological alterations that contribute to a number of disorders. Poor sleep quality is believed to contribute to the pathogenesis of these disorders through interactions with the hypothalamic-pituitary-adrenal (HPA) axis. The present study investigated the effect of one and three days of restricted sleep on HPA axis reactivity. Male and female C57BL/6J (n = 8/group) mice were sleep-deprived for a 20 h period for one day or three consecutive days using the modified multiple platform method, and then subjected to acute restraint stress. In response to sleep restriction, males showed blunted restraint-induced rises in CORT relative to controls. After three days of restricted sleep, females showed a similar attenuation in restraint-induced CORT. However, this effect was ablated after a single day of sleep restriction. Analyses of gene expression revealed significant elevations in the expression of pituitary HPA axis regulatory genes proopiomelanocortin and corticotropin releasing factor receptor 1 in both sexes following sleep restriction. In males, but not females, adrenal mRNA expression of 11ß-hydroxylase and melanocortin receptor 2 were also increased. Altogether, these data suggest several possible mechanisms are involved in the HPA axis dysregulation following sleep restriction, and that there are sex differences in how the HPA axis responds to sleep loss.Lay summarySleep restriction alters the stress response differently in males and females following varying nights of sleep restriction. These alterations are accompanied by changes in gene expression in the pituitary and adrenal glands.

Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation.

BACKGROUND: Increased secretion of growth hormone leads to gigantism in children and acromegaly in adults; the genetic causes of gigantism and acromegaly are poorly understood. METHODS: We performed clinical and genetic studies of samples obtained from 43 patients with gigantism and then sequenced an implicated gene in samples from 248 patients with acromegaly. RESULTS: We observed microduplication on chromosome Xq26.3 in samples from 13 patients with gigantism; of these samples, 4 were obtained from members of two unrelated kindreds, and 9 were from patients with sporadic cases. All the patients had disease onset during early childhood. Of the patients with gigantism who did not carry an Xq26.3 microduplication, none presented before the age of 5 years. Genomic characterization of the Xq26.3 region suggests that the microduplications are generated during chromosome replication and that they contain four protein-coding genes. Only one of these genes, GPR101, which encodes a G-protein-coupled receptor, was overexpressed in patients' pituitary lesions. We identified a recurrent GPR101 mutation (p.E308D) in 11 of 248 patients with acromegaly, with the mutation found mostly in tumors. When the mutation was transfected into rat GH3 cells, it led to increased release of growth hormone and proliferation of growth hormone-producing cells. CONCLUSIONS: We describe a pediatric disorder (which we have termed X-linked acrogigantism [X-LAG]) that is caused by an Xq26.3 genomic duplication and is characterized by early-onset gigantism resulting from an excess of growth hormone. Duplication of GPR101 probably causes X-LAG. We also found a recurrent mutation in GPR101 in some adults with acromegaly. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and others.).

Dietary Isoflavone-Dependent and Estradiol Replacement Effects on Body Weight in the Ovariectomized (OVX) Rat.

17ß-Estradiol is known to regulate energy metabolism and body weight. Ovariectomy results in body weight gain while estradiol administration results in a reversal of weight gain. Isoflavones, found in rodent chow, can mimic estrogenic effects making it crucial to understand the role of these compounds on metabolic regulation. The goal of this study is to examine the effect of dietary isoflavones on body weight regulation in the ovariectomized rat. This study will examine how dietary isoflavones can interact with estradiol treatment to affect body weight. Consistent with previous findings, animals fed an isoflavone-rich diet had decreased body weight (p<0.05), abdominal fat (p<0.05), and serum leptin levels (p<0.05) compared to animals fed an isoflavone-free diet. Estradiol replacement resulted in decreased body weight (p<0.05), abdominal fat (p<0.05), and serum leptin (p<0.05). Current literature suggests the involvement of cytokines in the inflammatory response of body weight gain. We screened a host of cytokines and chemokines that may be altered by dietary isoflavones or estradiol replacement. Serum cytokine analysis revealed significant (p<0.05) diet-dependent increases in inflammatory cytokines (keratinocyte-derived chemokine). The isoflavone-free diet in OVX rats resulted in the regulation of the following cytokines and chemokines: interleukin-10, interleukin-18, serum regulated on activation, normal T cell expressed and secreted, and monocyte chemoattractant protein-1 (p<0.05). Overall, these results reveal that estradiol treatment can have differential effects on energy metabolism and body weight regulation depending on the presence of isoflavones in rodent chow.

Chronically stressed male and female mice show a similar peripheral and central pro-inflammatory profile after an immune challenge.

Although acute stressors are known for stimulating the production of glucocorticoids and pro-inflammatory cytokines in rodents, the effects of chronic stressors on cytokine levels and the activation of the hypothalamic-pituitary-adrenal (HPA) axis, especially in response to a subsequent challenge, are less clear. In this study, male and female mice were exposed to 6 weeks of chronic variable stress (CVS) and the peripheral and central levels of IL-1ß, IL-6, and TNF-α, as well as the HPA axis reactivity, were measured after an acute injection of LPS. The findings indicate that the pro-inflammatory profile in the plasma, regardless of stress exposure, was similar between male and female animals, whereas there was a region-, sex-, and stress-dependent pattern in the brain. Exposure to chronic stressors blunted the HPA reactivity to the LPS challenge, indicating a modulatory effect on the stress axis responsiveness.

Effects of Repetitive Mild Traumatic Brain Injury on Corticotropin-Releasing Factor Modulation of Lateral Habenula Excitability and Motivated Behavior.

Mild traumatic brain injury (mTBI) is a significant health burden due to mTBI-related chronic debilitating cognitive and psychiatric morbidities. Recent evidence from our laboratory suggests a possible dysregulation within reward/motivational circuit function at the level of a subcortical structure, the lateral habenula (LHb), where we demonstrated a causal role for hyperactive LHb in mTBI-induced motivational deficits in self-care grooming behavior in young adult male mice when exposed to mTBI injury during late adolescence (at ~8 weeks old). Here we extended this observation by further characterizing neurobehavioral effects of this repetitive closed head injury model of mTBI in both young adult male and female mice on LHb excitability, corticotropin releasing factor (CRF) modulation of LHb activity, and behavioral responses of motivation to self-care behavior, and approach versus avoidance behavior in the presence of a social- or threat-related stimulus. We show that mTBI increases LHb spontaneous tonic activity in female mice similar to what we previously observed in male mice as well as promoting LHb neuronal hyperexcitability and hyperpolarization-induced LHb bursting in both male and female mice. Interestingly, mTBI only increases LHb intrinsic excitability in male mice coincident with higher levels of the hyperpolarization-activated cation currents (HCN/Ih) and reduces levels of the M-type potassium currents while potentiating M-currents without altering intrinsic excitability in LHb neurons of female mice. Since persistent dysregulation of brain CRF systems is suggested to contribute to chronic psychiatric morbidities and that LHb neurons are highly responsive to CRF, we then tested whether LHb CRF subsystem becomes engaged following mTBI. We found that in vitro inhibition of CRF receptor type 1 (CRFR1) within the LHb reverses mTBI-induced enhancement of LHb tonic activity and hyperexcitability in both sexes, suggesting that an augmented intra-LHb CRF-CRFR1-mediated signaling contributes to the overall LHb hyperactivity following mTBI. Behaviorally, mTBI diminishes motivation for self-care grooming in female mice as in male mice. mTBI also alters defensive behaviors in the looming shadow task by shifting the innate defensive behaviors towards more passive action-locking rather than escape behaviors in response to an aerial threat in both male and female mice as well as prolonging the latency to escape responses in female mice. While, this model of mTBI reduces social preference in male mice, it induces higher social novelty seeking during the novel social encounters in both male and female mice. Overall, our study provides further translational validity for the use of this preclinical model of mTBI for investigation of mTBI-related reward circuit dysfunction and mood/motivation-related behavioral deficits in both sexes while uncovering a few sexually dimorphic neurobehavioral effects of this model that may differentially affect young males and females when exposed to this type of mTBI injury during late adolescence.

Effects of Repetitive Mild Traumatic Brain Injury on Corticotropin-Releasing Factor Modulation of Lateral Habenula Excitability and Motivated Behavior.

Mild traumatic brain injury (mTBI) is a significant health burden due to mTBI-related chronic debilitating cognitive and psychiatric morbidities. Recent evidence from our laboratory suggests a possible dysregulation within reward/motivational circuit function at the level of a subcortical structure, the lateral habenula (LHb), where we demonstrated a causal role for hyperactive LHb in mTBI-induced motivational deficits in self-care grooming behavior in young adult male mice when exposed to mTBI injury during late adolescence (at ~8 weeks old). Here we extended this observation by further characterizing neurobehavioral effects of this repetitive closed head injury model of mTBI in both young adult male and female mice on LHb excitability, corticotropin releasing factor (CRF) modulation of LHb activity, and behavioral responses of motivation to self-care behavior, and approach versus avoidance behavior in the presence of a social- or threat-related stimulus. We show that mTBI increases LHb spontaneous tonic activity in female mice similar to what we previously observed in male mice as well as promoting LHb neuronal hyperexcitability and hyperpolarization-induced LHb bursting in both male and female mice. Interestingly, mTBI only increases LHb intrinsic excitability in male mice coincident with higher levels of the hyperpolarization-activated cation currents (HCN/Ih) and reduces levels of the M-type potassium currents while potentiating M-currents without altering intrinsic excitability in LHb neurons of female mice. Since persistent dysregulation of brain CRF systems is suggested to contribute to chronic psychiatric morbidities and that LHb neurons are highly responsive to CRF, we then tested whether LHb CRF subsystem becomes engaged following mTBI. We found that in vitro inhibition of CRF receptor type 1 (CRFR1) within the LHb normalizes mTBI-induced enhancement of LHb tonic activity and hyperexcitability in both sexes, suggesting that an augmented intra-LHb CRF-CRFR1-mediated signaling contributes to the overall LHb hyperactivity following mTBI. Behaviorally, mTBI diminishes motivation for self-care grooming in female mice as in male mice. mTBI also alters defensive behaviors in the looming shadow task by shifting the innate defensive behaviors towards more passive action-locking rather than escape behaviors in response to an aerial threat in both male and female mice as well as prolonging the latency to escape responses in female mice. While, this model of mTBI reduces social preference in male mice, it induces higher social novelty seeking during the novel social encounters in both male and female mice. Overall, our study provides further translational validity for the use of this preclinical model of mTBI for investigation of mTBI-related reward circuit dysfunction and mood/motivation-related behavioral deficits in both sexes while uncovering a few sexually dimorphic neurobehavioral effects of this model that may differentially affect young males and females when exposed to this type of mTBI injury during late adolescence.

The role of GnRH metabolite, GnRH-(1-5), in endometrial cancer.

From the time of its discovery and isolation in the mammalian hypothalamus, the decapeptide, gonadotropin-releasing hormone (GnRH), has also been found to be expressed in non-hypothalamic tissues and can elicit a diverse array of functions both in the brain and periphery. In cancer, past studies have targeted the gonadotropin-releasing hormone receptors (GnRHR) as a way to treat reproductive cancers due to its anti-tumorigenic effects. On the contrary, its metabolite, GnRH-(1-5), behaves divergently from its parental peptide through putative orphan G-protein coupled receptor (oGPCR), GPR101. In this review, we will focus on the potential roles of GnRH-(1-5) in the periphery with an emphasis on its effects on endometrial cancer progression.

Physical Health and Well-being: Updates and the Way Ahead.

INTRODUCTION: The Women in Combat Summit 2021 "Forging the Future: How Women Enhance the Fighting Force" took place during February 9-11, 2021, via a virtual conference platform. The third and final day of the Summit regarded the physical health and well-being of military women and included the topics of urogenital health, nutrition and iron-deficiency anemia, unintended pregnancy and contraception, and traumatic brain injury. MATERIALS AND METHODS: After presentations on the topics earlier, interested conference attendees were invited to participate in focus groups to discuss and review policy recommendations for physical health and well-being in military women. Discussions centered around the topics discussed during the presentations, and suggestions for future Women in Combat Summits were noted. Specifics of the methods of the Summit are presented elsewhere in this supplement. RESULTS: We formulated research and policy recommendations for urogenital health, nutrition and iron-deficiency anemia, contraception and unintended pregnancy, and traumatic brain injury. CONCLUSIONS: In order to continue to develop the future health of military women, health care providers, researchers, and policymakers should consider the recommendations made in this supplement as they continue to build on the state of the science and forge the future.

The Effects of Chronic Variable Stress and Photoperiod Alteration on the Hypothalamic-Pituitary-Adrenal Axis Response and Behavior of Mice.

The hypothalamic-pituitary-adrenal (HPA) axis mediates the physiological response to stressors and also synchronizes different physiological systems to environmental cues. Changes in day length (i.e., photoperiod) as well as chronic exposure to stressors are known to impact the HPA axis activity regulating the levels of glucocorticoid hormones. Over-exposure to inappropriate levels of glucocorticoids has been implicated in increased disease risk. In the present study, we examined the impact of chronic stress, using a chronic variable stress (CVS) paradigm, in combination with changes in photoperiod on physiological and behavioral measures, as well as on the reactivity and regulation of the HPA axis, in male and female mice. Six weeks of CVS, regardless of the photoperiod condition, decreased the body weight and attenuated the HPA axis reactivity to an acute stressor in both sexes. The attenuated HPA axis reactivity observed in stressed animals was related to reduced Pro-opiomelanocortin (POMC) mRNA levels in the pituitary of females. The gene expression analyses of key regulators of the HPA axis also indicated a sex-dependent effect with opposite patterns in the pituitary and adrenal glands. CVS effects on behavior were limited and related to an anxiety-like phenotype in both sexes, regardless of photoperiod condition. Our findings highlight sex-specific differences in the HPA axis and also sex-dependent effects of CVS on physiological parameters.

Glucocorticoid regulation of diurnal spine plasticity in the murine ventromedial prefrontal cortex.

The ventromedial prefrontal cortex (vmPFC) regulates fear acquisition, fear extinction, mood, and HPA axis function. Multiple brain regions exhibit time-of-day dependent variations in learning, long term potentiation (LTP), and dendritic morphology. Glucocorticoids have been implicated in the regulation of dendritic structure in the context of stress. Glucocorticoids are also known to regulate molecular clock entrainment via upregulation of Per1 transcription. In the present study, C57BL/6 N mice were sacrificed at three distinct times of day (ZT3, ZT12, and ZT16, lights off at ZT12) and Per1 mRNA expression was measured in the infralimbic and prelimbic vmPFC subregions using droplet digital (dd) PCR after recovering from adrenalectomy or sham surgery for 10 days. Sham mice showed Per1 rhythmicity in both infralimbic (IL) and prelimbic (PL) cortex, with peak expression occurring at ZT12. Adrenalectomized mice showed reductions in Per1 amplitude at ZT12 in both IL and PL, suggesting that the vmPFC molecular clock is entrained by diurnal glucocorticoid oscillations. Thy1-eGFP mice were used to visualize and quantify dendritic spine density on deep layer pyramidal dendrites at ZT 3, 12, and 16. Spine density in both PL and IL exhibited changes between the light (inactive) and dark (active) phases, with peak spine density observed at ZT16 and trough spine density observed at ZT3. These changes in spine density were restricted to changes in long thin and stubby type spines. To determine if changes in spine density is regulated by glucocorticoid oscillations, the 11ß-hydroxylase inhibitor metyrapone was administered 2 h prior to the onset of the active phase (ZT10) daily for 7 days. Metyrapone administration blocked both the diurnal peak of plasma corticosterone and peak spine densities in the IL and PL at ZT16. These results suggest that vmPFC molecular clock gene and dendritic spine diurnal rhythms depend on intact diurnal glucocorticoid oscillations.

Long-term increase in sensitivity to ketamine's behavioral effects in mice exposed to mild blast induced traumatic brain injury.

Neurobehavioral deficits emerge in nearly 50% of patients following a mild traumatic brain injury (TBI) and may persist for months. Ketamine is used frequently as an anesthetic/analgesic and for management of persistent psychiatric complications. Although ketamine may produce beneficial effects in patients with a history of TBI, differential sensitivity to its impairing effects could make the therapeutic use of ketamine in TBI patients unsafe. This series of studies examined male C57BL/6 J mice exposed to a mild single blast overpressure (mbTBI) for indications of altered sensitivity to ketamine at varying times after injury. Dystaxia (altered gait), diminished sensorimotor gating (reduced prepulse inhibition) and impaired working memory (step-down inhibitory avoidance) were examined in mbTBI and sham animals 15 min following intraperitoneal injections of saline or R,S-ketamine hydrochloride, from day 7-16 post injury and again from day 35-43 post injury. Behavioral performance in the forced swim test and sucrose preference test were evaluated on day 28 and day 74 post injury respectively, 24 h following drug administration. Dynamic gait stability was compromised in mbTBI mice on day 7 and 35 post injury and further exacerbated following ketamine administration. On day 14 and 42 post injury, prepulse inhibition was robustly decreased by mbTBI, which ketamine further reduced. Ketamine-associated memory impairment was apparent selectively in mbTBI animals 1 h, 24 h and day 28 post shock (tested on day 15/16/43 post injury). Ketamine selectively reduced immobility scores in the FST in mbTBI animals (day 28) and reversed mbTBI induced decreases in sucrose consumption (Day 74). These results demonstrate increased sensitivity to ketamine in mice when tested for extended periods after TBI. The results suggest that ketamine may be effective for treating neuropsychiatric complications that emerge after TBI but urge caution when used in clinical practice for enhanced sensitivity to its side effects in this patient population.

Effects of immobilization stress and hormonal treatment on nociception.

The purpose of this study was to evaluate the effects of stress and estradiol (E2) on pain tolerance. Ovariectomized rats were assigned to treatment groups based on a 2 x 4 factorial design comprising stress (nonstress x stress) and hormone treatment vehicle x E2 [0.25 mg/kg/d]) x estrogen receptor alpha (ERalpha)-selective agonist propyl pyrazole triol (1 mg/kg/d) x estrogen receptor beta (ERbeta)-selective agonist diarylpropionitrile (1 mg/kg/d). Stressed animals underwent daily 60-minute immobilization for 22 days. Pain tolerance was assessed with the hot plate test, an acute thermal pain test. In this study, stressed rats showed increased (P < .05) pain tolerance compared with nonstressed rats (25.0 +/- 1.92 s vs 20.4 +/- 1.02 s, respectively). Increased (P < .05) pain threshold was observed in nonstressed and stressed rats treated with E2 and the ERalpha agonist compared with vehicle-treated rats. Interestingly, the ERbeta agonist only increased (P < .10) pain thresholds in stressed rats. Stressed rats exhibited higher (P < .05) beta-endorphin levels compared with nonstressed rats in all hormone-treatment groups. With the exception of stressed rats treated with the ERbeta agonist, there was no hormone effect on beta-endorphin levels. These studies suggest that E2's effect on pain thresholds may be mediated via the ERalpha, while the interaction between chronic stress and ERbeta may also enhance pain threshold.

RNA-sequencing of AVPV and ARH reveals vastly different temporal and transcriptomic responses to estradiol in the female rat hypothalamus.

In females, estrogens have two main modes of action relating to gonadotropin secretion: positive feedback and negative feedback. Estrogen positive and negative feedback are controlled by different regions of the hypothalamus: the preoptic area/anterior portion (mainly the anteroventral periventricular nucleus, AVPV) of the hypothalamus is associated with estrogen positive feedback while the mediobasal hypothalamus (mainly the arcuate nucleus of the hypothalamus, ARH), is associated with estrogen negative feedback. In this study, we examined the temporal pattern of gene transcription in these two regions following estrogen treatment. Adult, ovariectomized, Long Evans rats received doses of estradiol benzoate (EB) or oil every 4 days for 3 cycles. On the last EB priming cycle, hypothalamic tissues were dissected into the AVPV+ and ARH+ at 0 hrs (baseline/oil control), 6 hrs, or 24 hrs after EB treatment. RNA was extracted and sequenced using bulk RNA sequencing. Differential gene analysis, gene ontology, and weighted correlation network analysis (WGCNA) was performed. Overall, we found that the AVPV+ and ARH+ respond differently to estradiol stimulation. In both regions, estradiol treatment resulted in more gene up-regulation than down-regulation. S100g was very strongly up-regulated by estradiol in both regions at 6 and 24 hrs after EB treatment. In the AVPV+ the highest number of differentially expressed genes occurred 24 hrs after EB. In the ARH+, the highest number of genes differentially expressed by EB occurred between 6 and 24 hrs after EB, while in the AVPV+, the fewest genes changed their expression between these time points, demonstrating a temporal difference in the way that EB regulates transcription these two areas. Several genes strongly implicated in gonadotropin release were differentially affected by estradiol including Esr1, encoding estrogen receptor-α and Kiss1, encoding kisspeptin. As an internal validation, Kiss1 was up-regulated in the AVPV+ and down-regulated in the ARH+. Gene network analysis revealed the vastly different clustering of genes modulated by estradiol in the AVPV+ compared with the ARH+. These results indicate that gene expression in these two hypothalamic regions have specific responses to estradiol in timing and direction.

Blast-Induced Mild Traumatic Brain Injury Alterations of Corticotropin-Releasing Factor Neuronal Activity in the Mouse Hypothalamic Paraventricular Nucleus.

Blast-induced mild traumatic brain injury (mbTBI) is the most common cause of TBI in US service members and veterans. Those exposed to TBI are at greater risk of developing neuropsychiatric disorders such as posttraumatic stress disorder, anxiety and depressive disorders, and substance use disorders following TBI. Previously, we have demonstrated that mbTBI increases anxiety-like behaviors in mice and dysregulates stress at the level of corticotropin-releasing factor (CRF) neurons in the paraventricular nucleus (PVN). To expand on how mTBI may dysregulate the stress axis centrally, here PVN CRF neuronal activity was evaluated using whole cell-patch clamp recordings in hypothalamic slices from sham and mbTBI adult male CRF:tdTomato mice 7 days post-injury. We found that mbTBI generally did not affect the neuronal excitability and intrinsic membrane properties of PVN CRF neurons; this injury selectively increased the frequency of spontaneous neuronal firing of PVN CRF neurons localized to the dorsal PVN (dPVN) but not ventral PVN (vPVN). Consistently, mbTBI-induced dPVN CRF hyperactivity was associated with pre- and post-synaptic depression of spontaneous GABAergic transmission onto dPVN CRF neurons suggesting that mbTBI-induced GABAergic synaptic dysfunction may underlie dPVN CRF neuronal hyperactivity and increases in dPVN CRF signaling. The present results provide the first evidence for mbTBI-induced alterations in PVN CRF neuronal activity and GABAergic synaptic function that could mediate hypothalamic CRF dysregulation following mbTBI contributing to stress psychopathology associated with blast injury.

Gut microbiota and metabolic marker alteration following dietary isoflavone-photoperiod interaction.

Introduction: The interaction between isoflavones and the gut microbiota has been highlighted as a potential regulator of obesity and diabetes. In this study, we examined the interaction between isoflavones and a shortened activity photoperiod on the gut microbiome. Methods: Male mice were exposed to a diet containing no isoflavones (NIF) or a regular diet (RD) containing the usual isoflavones level found in a standard vivarium chow. These groups were further divided into regular (12L:12D) or short active (16L:8D) photoperiod, which mimics seasonal changes observed at high latitudes. White adipose tissue and genes involved in lipid metabolism and adipogenesis processes were analysed. Bacterial genomic DNA was isolated from fecal boli, and 16S ribosomal RNA sequencing was performed. Results: NIF diet increased body weight and adipocyte size when compared to mice on RD. The lack of isoflavones and photoperiod alteration also caused dysregulation of lipoprotein lipase (Lpl), glucose transporter type 4 (Glut-4) and peroxisome proliferator-activated receptor gamma (Pparg) genes. Using 16S ribosomal RNA sequencing, we found that mice fed the NIF diet had a greater proportion of Firmicutes than Bacteroidetes when compared to animals on the RD. These alterations were accompanied by changes in the endocrine profile, with lower thyroid-stimulating hormone levels in the NIF group compared to the RD. Interestingly, the NIF group displayed increased locomotion as compared to the RD group. Conclusion: Together, these data show an interaction between the gut bacterial communities, photoperiod length and isoflavone compounds, which may be essential for understanding and improving metabolic health.

Comparative transcriptome analysis between patient and endometrial cancer cell lines to determine common signaling pathways and markers linked to cancer progression.

The rising incidence and mortality of endometrial cancer (EC) in the United States calls for an improved understanding of the disease's progression. Current methodologies for diagnosis and treatment rely on the use of cell lines as models for tumor biology. However, due to inherent heterogeneity and differential growing environments between cell lines and tumors, these comparative studies have found little parallels in molecular signatures. As a consequence, the development and discovery of preclinical models and reliable drug targets are delayed. In this study, we established transcriptome parallels between cell lines and tumors from The Cancer Genome Atlas (TCGA) with the use of optimized normalization methods. We identified genes and signaling pathways associated with regulating the transformation and progression of EC. Specifically, the LXR/RXR activation, neuroprotective role for THOP1 in Alzheimer's disease, and glutamate receptor signaling pathways were observed to be mostly downregulated in advanced cancer stage. While some of these highlighted markers and signaling pathways are commonly found in the central nervous system (CNS), our results suggest a novel function of these genes in the periphery. Finally, our study underscores the value of implementing appropriate normalization methods in comparative studies to improve the identification of accurate and reliable markers.

Is the metalloendopeptidase EC 3.4.24.15 (EP24.15), the enzyme that cleaves luteinizing hormone-releasing hormone (LHRH), an activating enzyme?

LHRH (GNRH) was first isolated in the mammalian hypothalamus and shown to be the primary regulator of the reproductive neuroendocrine axis comprising of the hypothalamus, pituitary and gonads. LHRH acts centrally through its initiation of pituitary gonadotrophin release. Since its discovery, this form of LHRH (LHRH-I) has been shown to be one of over 20 structural variants with a variety of roles in both the brain and peripheral tissues. LHRH-I is processed by a zinc metalloendopeptidase EC 3.4.24.15 (EP24.15) that cleaves the hormone at the fifth and sixth bond of the decapeptide (Tyr(5)-Gly(6)) to form LHRH-(1-5). We have previously reported that the auto-regulation of LHRH-I (GNRH1) gene expression and secretion can also be mediated by itself and its processed peptide, LHRH-(1-5), centrally and in peripheral tissues. In this review, we present the evidence that EP24.15 is the main enzyme of LHRH metabolism. Following this, we look at the metabolism of other neuropeptides where an active peptide fragments is formed during degradation and use this as a platform to postulate that EP24.15 may also produce an active peptide fragment in the process of breaking down LHRH. We close this review by the role EP24.15 may have in regulation of the complex LHRH system.

Sex-related differences in intravenous ketamine effects on dissociative stereotypy and antinociception in male and female rats.

Ketamine, a multimodal dissociative anesthetic drug, is widely used to treat various conditions including acute pain and treatment-resistant depression. We previously reported that subanesthetic doses of intravenous (i.v.) ketamine produced transient dissociative stereotypy and antinociception in male rats. However, sex-related differences in the effects of i.v. ketamine on these measures are not well characterized. Adult male and female Sprague-Dawley rats (10 weeks old) received an i.v. bolus saline or ketamine (2 and 5 mg/kg), and dissociative stereotypy (head weaving, ataxia, and circling) and natural behaviors (horizontal activity, rearing, and grooming) were quantified over a 10-min period. Ten minutes after the behavioral observation, antinociception was measured using a tail flick test. The i.v. ketamine administration increased head weaving, ataxia, circling, and horizontal activity while decreasing rearing and grooming behaviors in male and female rats. Following 5 mg/kg ketamine administration, ataxia was greater in female rats, while head weaving was greater in male rats. Among the female rats, head weaving was greater in the low estrogen group (diestrus phase) as compared to the high estrogen group (proestrus/estrus phase). Ketamine doses (2 and 5 mg/kg) produced antinociception in male and female rats, and female rats were more sensitive to the antinociceptive effects of 2 mg/kg ketamine. The current findings suggest that i.v. ketamine administration, a clinically relevant route of administration, may produce sex-related differences in dissociative behaviors and analgesia between males and females.

Vendor differences in anxiety-like behaviors in female and male Sprague Dawley rats.

Although Sprague Dawley outbred rats are commonly used in behavioral, physiological, and pharmacological studies, dramatic differences in responses may emerge from rats obtained from different suppliers even when sex, age, and environmental conditions are maintained constant. In the present study, we compared behavioral responses on three tests related to anxiety of Sprague Dawley female and male rats obtained from three different vendors in the United States: Charles River, Envigo, and Taconic. All rats were tested in the open field, light-dark box, and elevated zero maze. We found reduced time spent in the center area of the open field and decreased light compartment duration in the light-dark box test in female and male rats from Taconic compared to Charles River and Envigo rats, suggesting anxiety-like behaviors differ between the three vendors. No vendor differences were found on performance in the elevated zero maze. Furthermore, the contribution of stress hormones to vendor differences was examined by measuring serum corticosterone levels in rats 30 min after exposure to the elevated zero maze. There were no vendor differences in corticosterone levels, suggesting that endogenous levels of stress hormones most likely did not contribute to vendor differences in anxiety-like behaviors. Collectively, these findings highlight the importance of vendor selection of the Sprague Dawley stock for research involving behavioral tests related to anxiety.