Sodium butyrate prevents radiation-induced cognitive impairment by restoring pCREB/BDNF expression

Possible association of G6PC2 and MUC6 induced by low‑dose‑rate irradiation in mouse intestine with inflammatory bowel disease

Although there are several types of radiation exposure, it is debated whether low‑dose‑rate (LDR) irradiation (IR) affects the body. Since the small intestine is a radiation‑sensitive organ, the present study aimed to evaluate how it changes when exposed to LDR IR and identify the genes sensitive to these doses. After undergoing LDR (6.0 mGy/h) γ radiation exposure, intestinal RNA from BALB/c mice was extracted 1 and 24 h later. Mouse whole genome microarrays were used to explore radiation‑induced transcriptional alterations. Reverse transcription‑quantitative (RT‑q) PCR was used to examine time‑ and dose‑dependent radiation responses. The histopathological status of the jejunum in the radiated mouse was not changed by 10 mGy of LDR IR; however, 23 genes were upregulated in response to LDR IR of the jejunum in mice after 1 and 24 h of exposure. Upregulated genes were selected to validate the results of the RNA sequencing analysis for RT‑qPCR detection and results showed that only Na+/K+ transporting subunit α4, glucose‑6‑phosphatase catalytic subunit 2 (G6PC2), mucin 6 (MUC6) and transient receptor potential cation channel subfamily V member 6 levels significantly increased after 24 h of LDR IR. Furthermore, G6PC2 and MUC6 were notable genes induced by LDR IR exposure according to protein expression via western blot analysis. The mRNA levels of G6PC2 and MUC6 were significantly elevated within 24 h under three conditions: i) Exposure to LDR IR, ii) repeated exposure to LDR IR and iii) exposure to LDR IR in the presence of inflammatory bowel disease. These results could contribute to an improved understanding of immediate radiation reactions and biomarker development to identify radiation‑susceptible individuals before histopathological changes become noticeable. However, further investigation into the specific mechanisms involving G6PC2 and MUC6 is required to accomplish this.

Neuroprotective effects of saxagliptin against radiation-induced cognitive impairment: Insights on Akt/CREB/SIRT1/BDNF signaling pathway

Radiation-induced cognitive impairment has recently fueled scientific interest with an increasing prevalence of cancer patients requiring whole brain irradiation (WBI) in their treatment algorithm. Saxagliptin (SAXA), a dipeptidyl peptidase-IV (DPP-IV) inhibitor, has exhibited competent neuroprotective effects against varied neurodegenerative disorders. Hence, this study aimed at examining the efficacy of SAXA in alleviating WBI-induced cognitive deficits. Male Sprague Dawley rats were distributed into control group, WBI group exposed to 20 Gy ϒ-radiation, SAXA group treated for three weeks with SAXA (10 mg/kg. orally, once daily), and WBI/SAXA group exposed to 20 Gy ϒ-radiation then treated with SAXA (10 mg/kg. orally, once daily). SAXA effectively reversed memory deterioration and motor dysfunction induced by 20 Gy WBI during behavioural tests and preserved normal histological architecture of the hippocampal tissues of irradiated rats. Mechanistically, SAXA inhibited WBI-induced hippocampal oxidative stress via decreasing lipid peroxidation while restoring catalase antioxidant activity. Moreover, SAXA abrogated radiation-induced hippocampal neuronal apoptosis through downregulating proapoptotic Bcl-2 Associated X-protein (Bax) and upregulating antiapoptotic B-cell lymphoma 2 (Bcl-2) expressions and eventually diminishing expression of cleaved caspase 3. Furthermore, SAXA boosted hippocampal neurogenesis by upregulating brain-derived neurotrophic factor (BDNF) expression. These valuable neuroprotective capabilities of SAXA were linked to activating protein kinase B (Akt), and cAMP-response element-binding protein (CREB) along with elevating the expression of sirtuin 1 (SIRT-1). SAXA successfully mitigated cognitive dysfunction triggered by WBI, attenuated oxidative injury, and neuronal apoptosis, and enhanced neurogenesis through switching on Akt/CREB/BDNF/SIRT-1 signaling axes. Such fruitful neurorestorative effects of SAXA provide an innovative therapeutic strategy for improving the cognitive capacity of cancer patients exposed to radiotherapy.

TRIBUTYRIN REVERSES THE DELETERIOUS EFFECT OF SATURATED FAT ON WORKING MEMORY AND SYNAPTIC PLASTICITY IN JUVENILE MICE: DIFFERENTIAL EFFECTS IN MALES AND FEMALES

Short-chain fatty acids, such as butyric acid, derived from the intestinal fermentation of dietary fiber, have been proposed as a treatment for certain pathologies of the central nervous system. Our research group has shown that tributyrin (TB), a butyric acid prodrug, reverses deficits in spatial memory and modulates hippocampal synaptic plasticity. In the present work, diets enriched in either saturated (SOLF; Saturated OiL-enriched Food) or unsaturated (UOLF; Unsaturated OiL-enriched Food) fat were supplied during either 2 hours or 8 weeks to 5-week-old male and female mice undergoing a treatment schedule with TB. After the dietary treatment, spatial learning and memory (SLM) was assessed in both the Y-maze and the eight-arm radial maze (RAM). Hippocampal expression of genes involved in glutamatergic transmission as well as synaptic plasticity (long-term potentiation -LTP- and long-term depression -LTD-) were also analyzed. Our results show that 2 h of SOLF intake impaired LTP as well as the performance in the Y-Maze in juvenile male mice whereas no effect was found in females. Moreover, TB reversed both effects in SLM and LTP in males. In the case of chronic intake, both SOLF and UOLF deteriorated SLM measured in the RAM in both sexes whereas TB only reversed LTP impairment induced by SOLF in male mice. These results suggest that TB may have a potentially beneficial influence on learning and memory processes, contingent upon the type of diet and the sex of the individuals.

Microbiota-Gut-Brain Axis Dysregulation in Alzheimer's Disease: Multi-Pathway Effects and Therapeutic Potential

An essential regulator of neurodegenerative conditions like Alzheimer's disease (AD) is the gut microbiota. Alterations in intestinal permeability brought on by gut microbiota dysregulation encourage neuroinflammation, central immune dysregulation, and peripheral immunological dysregulation in AD, as well as hasten aberrant protein aggregation and neuronal death in the brain. However, it is unclear how the gut microbiota transmits information to the brain and how it influences brain cognition and function. In this review, we summarized the multiple pathways involved in the gut microbiome in AD and provided detailed treatment strategies based on the gut microbiome. Based on these observations, this review also discusses the problems, challenges, and strategies to address current therapeutic strategies.

Microbial perspective on the skin-gut axis and atopic dermatitis

Atopic dermatitis (AD) is a relapsing inflammatory skin condition that has become a global health issue with complex etiology and mounting prevalence. The association of AD with skin and gut microbiota has been revealed by virtue of the continuous development of sequencing technology and genomics analysis. Also, the gut-brain-skin axis and its mutual crosstalk mechanisms have been gradually verified. Accordingly, the microbiota-skin-gut axis also plays an important role in allergic skin inflammation. Herein, we reviewed the relationship between the microbiota-skin-gut axis and AD, explored the underlying signaling molecules and potential pathways, and focused on the potential mechanisms of probiotics, antimicrobial peptides (AMPs), coagulase-negative staphylococci transplantation, fecal microbiota transplantation, AMPs, and addition of essential fatty acids in alleviating AD, with the aim to provide a new perspective for targeting microbiota in the treatment of allergic skin inflammation.

Acetylome analyses provide novel insights into the effects of chronic intermittent hypoxia on hippocampus-dependent cognitive impairment

Introduction

Chronic intermittent hypoxia (CIH) can negatively affect hippocampal function through various molecular mechanisms. Protein acetylation, a frequently occurring modification, plays crucial roles in synaptic plasticity and cognitive processes. However, the global protein acetylation induced by CIH in the hippocampus and its specific effects on hippocampal function and behavior remain poorly understood.

Methods

To address this gap, we conducted a study using liquid chromatography-tandem mass spectrometry to analyze the lysine acetylome and proteome of the hippocampus in healthy adult mice exposed to intermittent hypoxia for 4 weeks (as a CIH model) compared to normoxic mice (as a control).

Results

We identified and quantified a total of 2,184 lysine acetylation sites in 1,007 proteins. Analysis of these acetylated proteins revealed disturbances primarily in oxidative phosphorylation, the tricarboxylic acid (TCA) cycle, and glycolysis, all of which are localized exclusively to mitochondria. Additionally, we observed significant changes in the abundance of 21 proteins, some of which are known to be associated with cognitive impairments.

Discussion

This study helps to elucidate the molecular mechanisms underlying CIH-induced changes in protein acetylation in the hippocampus. By providing valuable insights into the pathophysiological processes associated with CIH and their impacts on hippocampal function, our findings contribute to a better understanding of the consequences of CIH-induced changes in protein acetylation in the hippocampus and the potential role of CIH in cognitive impairment.

Agathobaculum butyriciproducens improves ageing-associated cognitive impairment in mice

AIMS

The gut microbiota is increasingly recognised as a pivotal regulator of immune system homeostasis and brain health. Recent research has implicated the gut microbiota in age-related cognitive impairment and dementia. Agathobaculum butyriciproducens SR79 T (SR79), which was identified in the human gut, has been reported to be beneficial in addressing cognitive deficits and pathophysiologies in a mouse model of Alzheimer's disease. However, it remains unknown whether SR79 affects age-dependent cognitive impairment.

MAIN METHOD

To explore the effects of SR79 on cognitive function during ageing, we administered SR79 to aged mice. Ageing-associated behavioural alterations were examined using the open field test (OFT), tail suspension test (TST), novel object recognition test (NORT), Y-maze alternation test (Y-maze), and Morris water maze test (MWM). We investigated the mechanisms of action in the gut and brain using molecular and histological analyses.

KEY FINDINGS

Administration of SR79 improved age-related cognitive impairment without altering general locomotor activity or depressive behaviour in aged mice. Furthermore, SR79 increased mature dendritic spines in the pyramidal cells of layer III and phosphorylation of CaMKIIα in the cortex of aged mice. Age-related activation of astrocytes in the cortex of layers III-V of the aged brain was reduced following SR79 administration. Additionally, SR79 markedly increased IL-10 production and Foxp3 and Muc2 mRNA expression in the colons of aged mice.

SIGNIFICANCE

These findings suggest that treatment with SR79 may be a beneficial microbial-based approach for enhancing cognitive function during ageing.

Advances in Brain-Gut-Microbiome Interactions: A Comprehensive Update on Signaling Mechanisms, Disorders, and Therapeutic Implications

The complex, bidirectional interactions between the brain, the gut, and the gut microbes are best referred to as the brain gut microbiome system. Animal and clinical studies have identified specific signaling mechanisms within this system, with gut microbes communicating to the brain through neuronal, endocrine, and immune pathways. The brain, in turn, modulates the composition and function of the gut microbiota through the autonomic nervous system, regulating gut motility, secretion, permeability, and the release of hormones impacting microbial gene expression. Perturbations at any level of these interactions can disrupt the intricate balance, potentially contributing to the pathogenesis of intestinal, metabolic, neurologic, and psychiatric disorders. Understanding these interactions and their underlying mechanisms holds promise for identifying biomarkers, as well as novel therapeutic targets, and for developing more effective treatment strategies for these complex disorders. Continued research will advance our knowledge of this system, with the potential for improved understanding and management of a wide range of disorders. This review provides an update on the current state of knowledge regarding this system, with a focus on recent advancements and emerging research areas.

Electroacupuncture Pretreatment Attenuates Learning Memory Impairment Induced by Repeated Propofol Exposure and Modulates Hippocampal Synaptic Plasticity in Rats

Background

Recurrent propofol anesthesia in the peak of neurodevelopment may lead to learning-memory decline. This study aimed to examine the efficacy of electroacupuncture pretreatment in ameliorating the aforementioned learning memory deficits and to explore its underlying mechanisms in a rat model of repeated propofol exposure.

Methods

10-day-old Sprague Dawley rats were randomly assigned to five groups: the control, fat emulsion, propofol, electroacupuncture pretreatment and electroacupuncture pretreatment combined with propofol groups. The electroacupuncture pretreatment involved three consecutive daily sessions, while propofol was received intraperitoneally once daily for five days. Following the modeling period, the rats' learning-memory performance was assessed using the New Novel Arm Y-maze, New Object Recognition, and Morris Water Maze. The Nissl staining method was used to observe the development of hippocampal neurons, while Golgi staining was employed to observe hippocampal synaptic development.

Results

The electroacupuncture pretreatment significantly attenuated the learning and memory impairment induced by recurring propofol exposure in rats. Additionally, it facilitated the development of hippocampal neurons and synaptic plasticity in the hippocampus. Immunofluorescence and Western Blot analyses were conducted to detect the expression of proteins related to apoptosis, learning memory, and synaptic plasticity. In the propofol group, the pro-apoptotic factors Caspase-3 and Bax was up-regulated, while the anti-apoptotic factor Bcl-2 was down-regulated, as compared to the blank group. Additionally, the phosphorylated cAMP-response element binding protein (pCREB), brain-derived neurotrophic factor (BDNF), synaptophysin, and growth associated protein-43 (GAP-43) was significantly decreased. In contrast, the electroacupuncture pretreatment combined with propofol group exhibited decreased the Caspase-3 and Bax and increased the Bcl-2, as compared to the propofol group, meanwhile, the pCREB, BDNF, Synaptophysin and GAP-43 was increased.

Conclusion

Our findings indicate that electroacupuncture pretreatment can alleviate the learning and memory impairment induced by recurring propofol exposure in rats. This is achieved by enhancing hippocampal synaptic plasticity, activating the pCREB/BDNF pathway and inhibiting neuronal apoptosis.

Probiotics, Live Biotherapeutic Products (LBPs), and Gut-Brain Axis Related Psychological Conditions: Implications for Research and Dietetics

It is well-known that probiotics have key roles in the crosstalk between the gut and brain in terms of nutrition and health. However, when investigating their role in nutrition and health, it can be important to discriminate probiotics used as foods, food supplements, or drugs. For clarification of this terminology, the Food and Drug Administration (FDA) has established a new "live biotherapeutic products" (LBP) category, expressing pharmaceutical expectations and to reduce confusion in the literature. Growing evidence advises that the community of microorganisms found in the gut microbiota is associated with psychological conditions. Hence, it is thought that LBPs may positively affect depression, anxiety, bipolar disorder, and schizophrenia by reducing inflammation, improving gut microbiota, and balancing gut neurometabolites. This review focuses on the specific position of probiotics as LBPs in psychological conditions. Condition-specific potential pathways and mechanisms of LBPs and the prominent strains are discussed in the light of novel studies for future research, dietetic and pharmaceutical applications.

Functional effects of gut microbiota-derived metabolites in Alzheimer's disease

The precise causation of Alzheimer's disease (AD) is unknown, and the factors that contribute to its etiology are highly complicated. Numerous research has been conducted to investigate the potential impact of various factors to the risk of AD development or prevention against it. A growing body of evidence suggests to the importance of the gut microbiota-brain axis in the modulation of AD, which is characterized by altered gut microbiota composition. These changes can alter the production of microbial-derived metabolites, which may play a detrimental role in disease progression by being involved in cognitive decline, neurodegeneration, neuroinflammation, and accumulation of Aβ and tau. The focus of this review is on the relationship between the key metabolic products of the gut microbiota and AD pathogenesis in the brain. Understanding the action of microbial metabolites can open up new avenues for the development of AD treatment targets.

Cracking Brain Diseases from Gut Microbes-Mediated Metabolites for Precise Treatment

The gut-brain axis has been a subject of significant interest in recent years. Understanding the link between the gut and brain axis is crucial for the treatment of disorders. Here, the intricate components and unique relationship between gut microbiota-derived metabolites and the brain are explained in detail. Additionally, the association between gut microbiota-derived metabolites and the integrity of the blood-brain barrier and brain health is emphasized. Meanwhile, gut microbiota-derived metabolites with their recent applications, challenges and opportunities their pathways on different disease treatment are focus discussed. The prospective strategy of gut microbiota-derived metabolites potential applies to the brain disease treatments, such as Parkinson's disease and Alzheimer's disease, is proposed. This review provides a broad perspective on gut microbiota-derived metabolites characteristics facilitate understand the connection between gut and brain and pave the way for the development of a new medication delivery system for gut microbiota-derived metabolites.

Gut microbiota and ionizing radiation-induced damage: Is there a link?

According to observational findings, ionizing radiation (IR) triggers dysbiosis of the intestinal microbiota, affecting the structural composition, function, and species of the gut microbiome and its metabolites. These modifications can further exacerbate IR-induced damage and amplify proinflammatory immune responses. Conversely, commensal bacteria and favorable metabolites can remodel the IR-disturbed gut microbial structure, promote a balance between anti-inflammatory and proinflammatory mechanisms in the body, and mitigate IR toxicity. The discovery of effective and safe remedies to prevent and treat radiation-induced injuries is vitally needed because of the proliferation of radiation toxicity threats produced by recent radiological public health disasters and increasing medical exposures. This review examines how the gut microbiota and its metabolites are linked to the processes of IR-induced harm. We highlight protective measures based on interventions with gut microbes to optimize the distress caused by IR damage to human health. We offer prospects for research in emerging and promising areas targeting the prevention and treatment of IR-induced damage.

Sodium butyrate attenuated diet-induced obesity, insulin resistance and inflammation partly by promoting fat thermogenesis via intro-adipose sympathetic innervation

Emerging evidence suggests that butyrate, a short-chain fatty acid, may have beneficial effects on obesity and its associated metabolic comorbidities, but the related molecular mechanism is largely unknown. This study aims to investigate the role of butyrate in diet-induced obesity and metabolic disorders and the relevant regulatory mechanisms. Here, dietary supplementation with Sodium butyrate (NaB) was carried out in mice fed with a high-fat diet (HFD) or chow diet. At week 14, mice on HFD displayed an obese phenotype and down-regulated expression of thermogenic regulators including Ucp-1 and Pgc-1α in adipose tissue. Excitingly, NaB add-on treatment abolished these detrimental effects. Moreover, the obesity-induced insulin resistance, inflammation, fatty liver, and intestinal dysfunction were also attenuated by NaB administration. Mechanistically, NaB can promote fat thermogenesis via the increased local sympathetic innervation of adipose tissue, and blocking the β3-adrenergic signaling pathway by 6-hydroxydopamine abolished NaB-induced thermogenesis. Our study reveals a potential pharmacological target for NaB to combat obesity and metabolic disorders.

Mechanisms of Short-Chain Fatty Acids Derived from Gut Microbiota in Alzheimer's Disease

Short-chain fatty acids (SCFAs) are important metabolites derived from the gut microbiota through fermentation of dietary fiber. SCFAs participate a number of physiological and pathological processes in the human body, such as host metabolism, immune regulation, appetite regulation. Recent studies on gut-brain interaction have shown that SCFAs are important mediators of gut-brain interactions and are involved in the occurrence and development of many neurodegenerative diseases, including Alzheimer's disease. This review summarizes the current research on the potential roles and mechanisms of SCFAs in AD. First, we introduce the metabolic distribution, specific receptors and signaling pathways of SCFAs in human body. The concentration levels of SCFAs in AD patient/animal models are then summarized. In addition, we illustrate the effects and mechanisms of SCFAs on the cognitive level, pathological features (Aβ and tau) and neuroinflammation in AD. Finally, we analyze the translational value of SCFAs as potential therapeutic targets for the treatment of AD.

The Efficacy of S-Adenosyl Methionine and Probiotic Supplementation on Depression: A Synergistic Approach

Depression is a common and serious health issue affecting around 280 million people around the world. Suicidal ideation more frequently occurs in people with moderate to severe depression. Psychotherapy and pharmacological drugs are the mainstay of available treatment options for depressive disorders. However, pharmacological options do not offer complete cure, especially in moderate to severe depression, and are often seen with a range of adverse events. S-adenosyl methionine (SAMe) supplementation has been widely studied, and an impressive collection of literature published over the last few decades suggests its antidepressant efficacy. Probiotics have gained significant attention due to their wide array of clinical uses, and multiple studies have explored the link between probiotic species and mood disorders. Gut dysbiosis is one of the risk factors in depression by inducing systemic inflammation accompanied by an imbalance in neurotransmitter production. Thus, concomitant administration of probiotics may be an effective treatment strategy in patients with depressed mood, particularly in resistant cases, as these can aid in dysbiosis, possibly resulting in the attenuation of systemic inflammatory processes and the improvement of the therapeutic efficacy of SAMe. The current review highlights the therapeutic roles of SAMe and probiotics in depression, their mechanistic targets, and their possible synergistic effects and may help in the development of food supplements consisting of a combination of SAMe and probiotics with new dosage forms that may improve their bioavailability.

The effect of serum lipids and short-chain fatty acids on cognitive functioning in drug-naïve, first episode schizophrenia patients

OBJECTIVE

Many studies have reported the important role of serum levels of short-chain fatty acids (SCFAs) in lipid metabolism and cognitive dysfunction. This study investigated the role of plasma lipids and SCFAs on cognitive functioning in drug- naïve first episode schizophrenia.

METHODS

This study recruited 44 schizophrenia inpatients and 35 healthy controls. Plasma lipid metabolism was characterized using standard enzymatic methods and an automated analyzer. Serum levels of SCFAs were measured by Gas chromatography mass spectrometry (GC-MS). Cognitive performance was evaluated by the MATRICS Consensus Cognitive Battery (MCCB).

RESULTS

The patient group showed significantly higher serum levels of total SCFAs, acetic acid, acetic acid/ propionic acid ratio, and poorer cognitive scores compared with the control group (p's < 0.05). Within the patient group, the lipid levels were positively associated with acetic acid/ propionic acid ratio (p's < 0.05). Furthermore, multiple regression analysis revealed that the interactions of LDL level × acetic acid/ propionic acid ratio was a significant predictor of the MCCB working memory, and processing speed subscale scores within the patient group.

CONCLUSIONS

Cognitive dysfunction and abnormal serum levels of SCFAs occur in the early phase of schizophrenia. Lipid metabolism and serum levels of SCFAs might be, both independently or interactively, associated with cognitive dysfunction in schizophrenia.

Prediction of the Mechanism of Sodium Butyrate against Radiation-Induced Lung Injury in Non-Small Cell Lung Cancer Based on Network Pharmacology and Molecular Dynamic Simulations and Molecular Dynamic Simulations

Background

Radiation-induced lung injury (RILI) is a severe side effect of radiotherapy for non-small cell lung cancer (NSCLC) ,and one of the major hindrances to improve the efficacy of radiotherapy. Previous studies have confirmed that sodium butyrate (NaB) has potential of anti-radiation toxicity. However, the mechanism of the protective effect of NaB against RILI has not yet been clarified. This study aimed to explore the underlying protective mechanisms of NaB against RILI in NSCLC through network pharmacology, molecular docking, molecular dynamic simulations and in vivo experiments.

Methods

The predictive target genes of NaB were obtained from the PharmMapper database and the literature review. The involved genes of RILI and NSCLC were predicted using OMIM and GeneCards database. The intersectional genes of drug and disease were identified using the Venny tool and uploaded to the Cytoscape software to identify 5 core target genes of NaB associated with RILI. The correlations between the 5 core target genes and EGFR, PD-L1, immune infiltrates, chemokines and chemokine receptors were analyzed using TIMER 2.0, TIMER and TISIDB databases. We constructed the mechanism maps of the 3 key signaling pathways using the KEGG database based on the results of GO and KEGG analyses from Metascape database. The 5 core target genes and drug were docked using the AutoDock Vina tool and visualized using PyMOL software. GROMACS software was used to perform 100 ns molecular dynamics simulation. Irradiation-induced lung injury model in mice were established to assess the therapeutic effects of NaB.

Results

A total of 51 intersectional genes involved in NaB against RILI in NSCLC were identified. The 5 core target genes were AKT1, TP53, NOTCH1, SIRT1, and PTEN. The expressions of the 5 core target genes were significantly associated with EGFR, PD-L1, immune infiltrates, chemokines and chemokine receptors, respectively. The results from GO analysis of the 51 intersectional genes revealed that the biological processes were focused on the regulation of smooth muscle cell proliferation, oxidative stress and cell death, while the three key KEGG pathways were enriched in PI3K-Akt signal pathway, p53 signal pathway, and FOXO signal pathway. The docking of NaB with the 5 core target genes showed affinity and stability, especially AKT1. In vivo experiments showed that NaB treatment significantly protected mice from RILI, with reduced lung histological damage. In addition, NaB treatment significantly inhibited the PI3K/Akt signaling pathway.

Conclusions

NaB may protect patients from RILI in NSCLC through multiple target genes including AKT1, TP53, NOTCH1, SIRT1 and PTEN, with multiple signaling pathways involving, including PI3K-Akt pathway, p53 pathway, and FOXO pathways. Our findings effectively provide a feasible theoretical basis to further elucidate the mechanism of NaB in the treatment of RILI.

Intake of flavonoids from Astragalus membranaceus ameliorated brain impairment in diabetic mice via modulating brain-gut axis

Background

Brain impairment is one of a major complication of diabetes. Dietary flavonoids have been recommended to prevent brain damage. Astragalus membranaceus is a herbal medicine commonly used to relieve the complications of diabetes. Flavonoids is one of the major ingredients of Astragalus membranaceus, but its function and mechanism on diabetic encepholopathy is still unknown.

Methods

Type 2 diabetes mellitus (T2DM) model was induced by high fat diet and STZ in C57BL/6J mice, and BEnd.3 and HT22 cell lines were applied in the in vitro study. Quality of flavonoids was evaluated by LC–MS/MS. Differential expressed proteins in the hippocampus were evaluated by proteomics; influence of the flavonoids on composition of gut microbiota was analyzed by metagenomics. Mechanism of the flavonoids on diabetic encepholopathy was analyzed by Q-PCR, Western Blot, and multi-immunological methods et al.

Results

We found that flavonoids from Astragalus membranaceus (TFA) significantly ameliorated brain damage by modulating gut-microbiota-brain axis: TFA oral administration decreased fasting blood glucose and food intake, repaired blood brain barrier, protected hippocampus synaptic function; improved hippocampus mitochondrial biosynthesis and energy metabolism; and enriched the intestinal microbiome in high fat diet/STZ-induced diabetic mice. In the in vitro study, we found TFA increased viability of HT22 cells and preserved gut barrier integrity in CaCO₂ monocellular layer, and PGC1α/AMPK pathway participated in this process.

Conclusion

Our findings demonstrated that flavonoids from Astragalus membranaceus ameliorated brain impairment, and its modulation on gut-brain axis plays a pivotal role. Our present study provided an alternative solution on preventing and treating diabetic cognition impairment.

Gut microbiota and neuropsychiatric disorders: Implications for neuroendocrine-immune regulation

Recently, increasing evidence has shown gut microbiota dysbiosis might be implicated in the physiological mechanisms of neuropsychiatric disorders. Altered microbial community composition, diversity and distribution traits have been reported in neuropsychiatric disorders. However, the exact pathways by which the intestinal microbiota contribute to neuropsychiatric disorders remain largely unknown. Given that the onset and progression of neuropsychiatric disorders are characterized with complicated alterations of neuroendocrine and immunology, both of which can be continually affected by gut microbiota via "microbiome-gut-brain axis". Thus, we assess the complicated crosstalk between neuroendocrine and immunological regulation might underlie the mechanisms of gut microbiota associated with neuropsychiatric disorders. In this review, we summarized clinical and preclinical evidence on the role of the gut microbiota in neuropsychiatry disorders, especially in mood disorders and neurodevelopmental disorders. This review may elaborate the potential mechanisms of gut microbiota implicating in neuroendocrine-immune regulation and provide a comprehensive understanding of physiological mechanisms for neuropsychiatric disorders.

Histone deacetylase in neuropathology

Neuroepigenetics, a new branch of epigenetics, plays an important role in the regulation of gene expression. Neuroepigenetics is associated with holistic neuronal function and helps in formation and maintenance of memory and learning processes. This includes neurodevelopment and neurodegenerative defects in which histone modification enzymes appear to play a crucial role. These modifications, carried out by acetyltransferases and deacetylases, regulate biologic and cellular processes such as apoptosis and autophagy, inflammatory response, mitochondrial dysfunction, cell-cycle progression and oxidative stress. Alterations in acetylation status of histone as well as non-histone substrates lead to transcriptional deregulation. Histone deacetylase decreases acetylation status and causes transcriptional repression of regulatory genes involved in neural plasticity, synaptogenesis, synaptic and neural plasticity, cognition and memory, and neural differentiation. Transcriptional deactivation in the brain results in development of neurodevelopmental and neurodegenerative disorders. Mounting evidence implicates histone deacetylase inhibitors as potential therapeutic targets to combat neurologic disorders. Recent studies have targeted naturally-occurring biomolecules and micro-RNAs to improve cognitive defects and memory. Multi-target drug ligands targeting HDAC have been developed and used in cell-culture and animal-models of neurologic disorders to ameliorate synaptic and cognitive dysfunction. Herein, we focus on the implications of histone deacetylase enzymes in neuropathology, their regulation of brain function and plausible involvement in the pathogenesis of neurologic defects.

Proteolytic cleavage of proBDNF to mBDNF in neuropsychiatric and neurodegenerative diseases

Brain-derived neurotrophic factor (BDNF) is involved in pathophysiological mechanisms in neuropsychiatric diseases, including depression, anxiety, and schizophrenia (SZ), as well as neurodegenerative diseases like Parkinson's disease (PD) and Alzheimer's disease (AD). An imbalance or insufficient pro-brain-derived neurotrophic factor (proBDNF) transformation into mature BDNF (mBDNF) is potentially critical to the disease pathogenesis by impairing neuronal plasticity as suggested by results from many studies. Thus, promoting proBDNF transformation into mBDNF is therefore hypothesized as beneficial for the treatment of neuropsychiatric and neurodegenerative diseases. ProBDNF is proteolytically cleaved into the mBDNF by intracellular furin/proprotein convertases and extracellular proteases (plasmin/matrix metallopeptidases). This article reviews the mechanisms of the conversion of proBDNF to mBDNF and the research status of intracellular/extracellular proteolytic proteases for neuropsychiatric and neurodegenerative disorders.

Fingolimod (FTY720) improves postoperative cognitive dysfunction in mice subjected to D-galactose-induced aging

Neurocognitive dysfunction is a common postoperative complication, especially in older adult patients. Fingolimod (FTY720) is a sphingosine-1-phosphate receptor modulator that has been found to be neuroprotective in several animal models of central nervous system disease. However, few reports have examined whether FTY720 could mitigate postoperative cognitive dysfunction. In this study, we investigated whether FTY720 could prevent postoperative neurocognitive impairment in mice subjected to D-galactose-induced aging. We induced an accelerated model of aging by administering an intraperitoneal injection of D-galactose. Subsequently, we performed a partial hepatolobectomy under sevoflurane anesthesia. FTY720 (1 mg/kg) was administered intraperitoneally 3 hours before and 24 hours after anesthesia and surgery. Our results indicated that anesthesia and surgery significantly impaired spatial memory in the Y-maze test 6 hours after surgery. We also found that problem solving ability and long-term memory in the puzzle box test on postoperative days 2-4 were significantly improved by FTY720 treatment. Immunohistochemical staining and western blot assay demonstrated that FTY720 significantly inhibited microglial activation in the hippocampal CA1 region of mice 6 hours and 3 days after anesthesia, and down-regulated the expression of synaptic-related proteins postsynaptic density protein 95 and GluR2 in the hippocampus. These results indicate that FTY720 improved postoperative neurocognitive dysfunction in mice subjected to D-galactose-induced aging. This study was approved by the Experimental Animal Ethics Committee of the Third Xiangya Hospital of Central South University of China (approval No. LLSC (LA) 2016-025) on September 27, 2016.

Proprotein convertase 1/3-mediated down-regulation of brain-derived neurotrophic factor in cortical neurons induced by oxygen-glucose deprivation

Brain-derived neurotrophic factor (BDNF) has robust effects on synaptogenesis, neuronal differentiation and synaptic transmission and plasticity. The maturation of BDNF is a complex process. Proprotein convertase 1/3 (PC1/3) has a key role in the cleavage of protein precursors that are directed to regulated secretory pathways; however, it is not clear whether PC1/3 mediates the change in BDNF levels caused by ischemia. To clarify the role of PC1/3 in BDNF maturation in ischemic cortical neurons, primary cortical neurons from fetal rats were cultured in a humidified environment of 95% N₂ and 5% CO₂ in a glucose-free Dulbecco’s modified Eagle’s medium at 37°C for 3 hours. Enzyme-linked immunosorbent assays and western blotting showed that after oxygen-glucose deprivation, the secreted and intracellular levels of BDNF were significantly reduced and the intracellular level of PC1/3 was decreased. Transient transfection of cortical neurons with a PC1/3 overexpression plasmid followed by oxygen-glucose deprivation resulted in increased PC1/3 levels and increased BDNF levels. When levels of the BDNF precursor protein were reduced, the concentration of BDNF in the culture medium was increased. These results indicate that PC1/3 cleavage of BDNF is critical for the conversion of pro-BDNF in rat cortical neurons during ischemia. The study was approved by the Animal Ethics Committee of Wuhan University School of Basic Medical Sciences.