Phosphorylated delta sleep inducing peptide restores spatial memory and p-CREB expression by improving sleep architecture at high altitude

Oral quercetin nanoparticles in hydrogel microspheres alleviate high-altitude sleep disturbance based on the gut-brain axis

High-altitude sleep disturbance is a common symptom of acute mountain sickness, which can be alleviated via modulation of the gut-brain axis. Quercetin (Que) is used to modulate gut microbiota and serves as a potential drug to regulate the gut-brain axis, but the poor solubility and bioavailability affect its biological functions. Here, Que nanoparticles (QNPs) were prepared with zein using an antisolvent method, and QNP-loaded calcium alginate hydrogel microspheres (QNP@HMs) were prepared using electrospinning technology to improve the gastrointestinal stability and intestinal adhesion of QNPs. In the mouse model of high-altitude sleep disturbance, oral administration of QNP@HMs before the mice entering high altitude prolonged sleep duration, improved blood cell recovery, spontaneous behavior and short-term memory, and reduced such inflammation factors as TNF-α and iNOS. Moreover, QNP@HMs enhanced the abundance of probiotics in the gut, including Lactobacillus and Lachnospira, and reduced intestinal inflammation. However, in the mice after gut sterilization by long-term oral antibiotics, QNP@HMs showed no therapeutic effect. QNP@HMs are a promising medication for the prevention of high-altitude sleep disturbance based on the gut-brain axis.

Combination of Walnut Peptide and Casein Peptide alleviates anxiety and improves memory in anxiety mices

Introduction

Anxiety disorders continue to prevail as the most prevalent cluster of mental disorders following the COVID-19 pandemic, exhibiting substantial detrimental effects on individuals' overall well-being and functioning. Even after a search spanning over a decade for novel anxiolytic compounds, none have been approved, resulting in the current anxiolytic medications being effective only for a specific subset of patients. Consequently, researchers are investigating everyday nutrients as potential alternatives to conventional medicines. Our prior study analyzed the antianxiety and memory-enhancing properties of the combination of Walnut Peptide (WP) and Casein Peptide (CP) in zebrafish.

Methods and Results

Based on this work, our current research further validates their effects in mice models exhibiting elevated anxiety levels through a combination of gavage oral administration. Our results demonstrated that at 170 + 300 mg human dose, the WP + CP combination significantly improved performances in relevant behavioral assessments related to anxiety and memory. Furthermore, our analysis revealed that the combination restores neurotransmitter dysfunction observed while monitoring Serotonin, gamma-aminobutyric acid (GABA), dopamine (DA), and acetylcholine (ACh) levels. This supplementation also elevated the expression of brain-derived neurotrophic factor mRNA, indicating protective effects against the neurological stresses of anxiety. Additionally, there were strong correlations among behavioral indicators, BDNF (brain-derived neurotrophic factor), and numerous neurotransmitters.

Conclusion

Hence, our findings propose that the WP + CP combination holds promise as a treatment for anxiety disorder. Besides, supplementary applications are feasible when produced as powdered dietary supplements or added to common foods like powder, yogurt, or milk.

Disrupted gut microbiota aggravates spatial memory dysfunction induced by high altitude exposure: A link between plateau environment and microbiome-gut-brain axis

Approximately 400 million people work and live in high-altitude areas and suffer from memory dysfunction worldwide. Until now, the role of the intestinal flora in plateau-induced brain damage has rarely been reported. To address this, we investigated the effect of intestinal flora on spatial memory impairment induced by high altitudes based on the microbiome-gut-brain axis theory. C57BL/6 mice were divided into three groups: control, high-altitude (HA), and high-altitude antibiotic treatment (HAA) group. The HA and HAA groups were exposed to a low-pressure oxygen chamber that simulated an altitude of 4000 m above sea level (m. a. s.l.) for 14 days, with the air pressure in the chamber set at 60-65 kPa. The results showed that spatial memory dysfunction induced by the high-altitude environment was aggravated by antibiotic treatment, manifesting as lowered escape latency and hippocampal memory-related proteins (BDNF and PSD-95). 16 S rRNA sequencing showed a remarkable separation of the ileal microbiota among the three groups. Antibiotic treatment exacerbated the reduced richness and diversity of the ileal microbiota in mice in the HA group. Lactobacillaceae were the main target bacteria and were significantly reduced in the HA group, which was exacerbated by antibiotic treatment. Meanwhile, reduced intestinal permeability and ileal immune function in mice exposed high-altitude environment was also aggravated by antibiotic treatment, as indicated by the lowered tight junction proteins and IL-1β and IFN-γ levels. Furthermore, indicator species analysis and Netshift co-analysis revealed that Lactobacillaceae (ASV11) and Corynebacteriaceae (ASV78, ASV25, and ASV47) play important roles in high-altitude exposure-induced memory dysfunction. Interestingly, ASV78 was negatively correlated with IL-1β and IFN-γ levels, indicating that ASV78 may be induced by reduced ileal immune function, which mediates high-altitude environment exposure-induced memory dysfunction. This study provides evidence that the intestinal flora is effective in preventing brain dysfunction caused by exposure to high-altitude environments, suggesting a relationship between the microbiome-gut-brain axis and altitude exposure.

Hypobaric Hypoxia Induces Deficits in Adult Neurogenesis and Social Interaction via Cyclooxygenase-1/ EP1 Receptor Pathway Activating NLRP3 Inflammasome

Low oxygen environments, like hypobaric hypoxia (HH), are common nodes in a number of diseases characterized by neuroinflammation, which is detrimental to the structural and functional aspects of hippocampal circuitry. Hypoxic conditions lead to elevation of inflammasome-mediated inflammation that may contribute to cognitive deficits. However, a systematic investigation of the impact of inflammasome-mediated neuroinflammation on the components of neurogenic niche during HH remains to be elusive. Cerebral hypoxia was induced in adult male Sprague Dawley rats via decreasing partial pressure of oxygen. The effect of HH (1, 3, and 7 days at 25,000 ft) on social memory, anxiety, adult neurogenesis, and NLRP3- (NLR family pyrin domain containing 3) mediated neuroinflammation in the dentate gyrus (DG) was explored in detail. Furthermore, we explored the therapeutic efficacy of cyclooxygenase-1 inhibitor (valeryl salicylate, 5 mg/kg/day, i.p.) and EP1 receptor (EP1R) antagonist (SC19220, 1 mg/kg/day, i.p.) on HH-induced deficits. Seven days of HH exposure induced alteration in social and anxiety-like behavior along with perturbation in adult neurogenesis. Elevation in NLRP3, caspase-1, and IL-1β levels was observed during HH from day 1. A notable increase in the COX-1/EP1R pathway in activated glial cells in DG was evident during HH. COX-1 inhibitor and EP1R antagonist mitigated the detrimental effects of HH on social memory, adult neurogenesis via blunting NLRP3-mediated inflammation. Our data showed induction of the COX-1/EP1R pathway in the glial cells, which is detrimental to neurogenesis and social memory, opening up the possibility that the COX-1/EP1R pathway is a plausible target for inflammasome-related neurogenesis impairments.

Methamphetamine exacerbates pathophysiology of traumatic brain injury at high altitude. Neuroprotective effects of nanodelivery of a potent antioxidant compound H-290/51

Military personnel are often exposed to high altitude (HA, ca. 4500-5000m) for combat operations associated with neurological dysfunctions. HA is a severe stressful situation and people frequently use methamphetamine (METH) or other psychostimulants to cope stress. Since military personnel are prone to different kinds of traumatic brain injury (TBI), in this review we discuss possible effects of METH on concussive head injury (CHI) at HA based on our own observations. METH exposure at HA exacerbates pathophysiology of CHI as compared to normobaric laboratory environment comparable to sea level. Increased blood-brain barrier (BBB) breakdown, edema formation and reductions in the cerebral blood flow (CBF) following CHI were exacerbated by METH intoxication at HA. Damage to cerebral microvasculature and expression of beta catenin was also exacerbated following CHI in METH treated group at HA. TiO2-nanowired delivery of H-290/51 (150mg/kg, i.p.), a potent chain-breaking antioxidant significantly enhanced CBF and reduced BBB breakdown, edema formation, beta catenin expression and brain pathology in METH exposed rats after CHI at HA. These observations are the first to point out that METH exposure in CHI exacerbated brain pathology at HA and this appears to be related with greater production of oxidative stress induced brain pathology, not reported earlier.

Endogenous Opiates and Behavior: 2018

This paper is the forty-first consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2018 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (2), the roles of these opioid peptides and receptors in pain and analgesia in animals (3) and humans (4), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (5), opioid peptide and receptor involvement in tolerance and dependence (6), stress and social status (7), learning and memory (8), eating and drinking (9), drug abuse and alcohol (10), sexual activity and hormones, pregnancy, development and endocrinology (11), mental illness and mood (12), seizures and neurologic disorders (13), electrical-related activity and neurophysiology (14), general activity and locomotion (15), gastrointestinal, renal and hepatic functions (16), cardiovascular responses (17), respiration and thermoregulation (18), and immunological responses (19).

Heat stress induced oxidative damage and perturbation in BDNF/ERK1/2/CREB axis in hippocampus impairs spatial memory

Heat exposure is an environmental stress that causes diverse heat related pathophysiological changes under extreme conditions. The brain including hippocampal region which is associated with learning and memory is significantly affected by heat stress resulting in memory impairment. However, the effect of heat on the spatial memory remains unclear. The present study aimed to explore the effect of heat stress on hippocampus and spatial memory in rats. Rat model of acute heat stress was used which was divided into two groups, viz. moderate heat stress (MHS) and severe heat stress (SHS). Redox parameters evaluation revealed that MHS and SHS exposure markedly increase the production of malondialdehyde (MDA), oxidised glutathione (GSSG), reactive oxidative species (ROS), protein oxidation level and decrease the reduced glutathione (GSH) levels in the hippocampal tissue. Furthermore, Cresyl Violet (CV) staining of hippocampal region showed higher pyknosis in rats exposed to SHS. Pronounced increase of caspase3 expression and Fluoro Jade-C (FJ-C) positive cells were observed in SHS resulting in neuronal injury and apoptosis in CA3 region of hippocampus culminating in spatial memory deficit. Our data also suggest that heat stress induces phospho Extracellular signal-regulated kinases (pERK)1/2 activation induced by Brain-derived neurotrophic factor (BDNF) leading to further activation of phospho cAMP-response element binding protein (pCREB) under MHS. However, during SHS, BDNF and pCREB expression were completely dysregulated and not sufficient to rescue cognitive decline in rats. In conclusion, SHS induces pathological alterations that include oxidative damage and apoptosis of hippocampal neurons, disturbing BDNF/ERK1/2/CREB axis that may affect spatial memory.