Butyrate enhances mitochondrial function during oxidative stress in cell lines from boys with autism

Hypoxia-inducible factor-driven glycolytic adaptations in host-microbe interactions

Mammalian cells utilize glucose as a primary carbon source to produce energy for most cellular functions. However, the bioenergetic homeostasis of cells can be perturbed by environmental alterations, such as changes in oxygen levels which can be associated with bacterial infection. Reduction in oxygen availability leads to a state of hypoxia, inducing numerous cellular responses that aim to combat this stress. Importantly, hypoxia strongly augments cellular glycolysis in most cell types to compensate for the loss of aerobic respiration. Understanding how this host cell metabolic adaptation to hypoxia impacts the course of bacterial infection will identify new anti-microbial targets. This review will highlight developments in our understanding of glycolytic substrate channeling and spatiotemporal enzymatic organization in response to hypoxia, shedding light on the integral role of the hypoxia-inducible factor (HIF) during host-pathogen interactions. Furthermore, the ability of intracellular and extracellular bacteria (pathogens and commensals alike) to modulate host cellular glucose metabolism will be discussed.

The Association Between Branched-Chain Amino Acid Concentrations and the Risk of Autism Spectrum Disorder in Preschool-Aged Children

Several studies have linked branched-chain amino acid (BCAA) metabolism disorders with autism spectrum disorder (ASD), but the results have been inconsistent. The purpose of this study was to explore the association between BCAA concentrations and the risk of ASD. A total of 313 participants were recruited from two tertiary referral hospitals from May 2018 to July 2021. Concentrations of BCAAs in dried blood spots were analyzed using liquid chromatography-tandem mass spectrometry-based analysis. Multivariate analyses and restricted cubic spline models were used to identify the association between BCAAs and the risk of ASD, and a nomogram was developed by using multivariate logistic regression and the risk was determined by receiver operating characteristic curve analysis and calibration curve analysis. Concentrations of total BCAA, valine, and leucine/isoleucine were higher in the ASD group, and all of them were positively and non-linearly associated with the risk of ASD even after adjusting for potential confounding factors such as age, gender, body mass index, and concentrations of BCAAs (P < 0.05). The nomogram integrating total BCAA and valine showed a good discriminant AUC value of 0.756 (95% CI 0.676-0.835). The model could yield net benefits across a reasonable range of risk thresholds. In the stratified analysis, the diagnostic ability of the model was more pronounced in children older than 3 years. We provide evidence that increased levels of BCAAs are associated with the risk of ASD, and the nomogram model of BCAAs presented here can serve as a marker for the early diagnosis of ASD.

Biomarkers of mitochondrial dysfunction in autism spectrum disorder: A systematic review and meta-analysis

Autism spectrum disorder (ASD) is a neurodevelopmental disorder affecting 1 in 36 children and is associated with physiological abnormalities, most notably mitochondrial dysfunction, at least in a subset of individuals. This systematic review and meta-analysis discovered 204 relevant articles which evaluated biomarkers of mitochondrial dysfunction in ASD individuals. Significant elevations (all p < 0.01) in the prevalence of lactate (17%), pyruvate (41%), alanine (15%) and creatine kinase (9%) were found in ASD. Individuals with ASD had significant differences (all p < 0.01) with moderate to large effect sizes (Cohen's d' ≥ 0.6) compared to controls in mean pyruvate, lactate-to-pyruvate ratio, ATP, and creatine kinase. Some studies found abnormal TCA cycle metabolites associated with ASD. Thirteen controlled studies reported mitochondrial DNA (mtDNA) deletions or variations in the ASD group in blood, peripheral blood mononuclear cells, lymphocytes, leucocytes, granulocytes, and brain. Meta-analyses discovered significant differences (p < 0.01) in copy number of mtDNA overall and in ND1, ND4 and CytB genes. Four studies linked specific mtDNA haplogroups to ASD. A series of studies found a subgroup of ASD with elevated mitochondrial respiration which was associated with increased sensitivity of the mitochondria to physiological stressors and neurodevelopmental regression. Lactate, pyruvate, lactate-to-pyruvate ratio, carnitine, and acyl-carnitines were associated with clinical features such as delays in language, social interaction, cognition, motor skills, and with repetitive behaviors and gastrointestinal symptoms, although not all studies found an association. Lactate, carnitine, acyl-carnitines, ATP, CoQ10, as well as mtDNA variants, heteroplasmy, haplogroups and copy number were associated with ASD severity. Variability was found across biomarker studies primarily due to differences in collection and processing techniques as well as the intrinsic heterogeneity of the ASD population. Several studies reported alterations in mitochondrial metabolism in mothers of children with ASD and in neonates who develop ASD. Treatments targeting mitochondria, particularly carnitine and ubiquinol, appear beneficial in ASD. The link between mitochondrial dysfunction in ASD and common physiological abnormalities in individuals with ASD including gastrointestinal disorders, oxidative stress, and immune dysfunction is outlined. Several subtypes of mitochondrial dysfunction in ASD are discussed, including one related to neurodevelopmental regression, another related to alterations in microbiome metabolites, and another related to elevations in acyl-carnitines. Mechanisms linking abnormal mitochondrial function with alterations in prenatal brain development and postnatal brain function are outlined. Given the multisystem complexity of some individuals with ASD, this review presents evidence for the mitochondria being central to ASD by contributing to abnormalities in brain development, cognition, and comorbidities such as immune and gastrointestinal dysfunction as well as neurodevelopmental regression. A diagnostic approach to identify mitochondrial dysfunction in ASD is outlined. From this evidence, it is clear that many individuals with ASD have alterations in mitochondrial function which may need to be addressed in order to achieve optimal clinical outcomes. The fact that alterations in mitochondrial metabolism may be found during pregnancy and early in the life of individuals who eventually develop ASD provides promise for early life predictive biomarkers of ASD. Further studies may improve the understanding of the role of the mitochondria in ASD by better defining subgroups and understanding the molecular mechanisms driving some of the unique changes found in mitochondrial function in those with ASD.

Sodium butyrate ameliorates high glucose-suppressed neuronal mitophagy by restoring PRKN expression via inhibiting the RELA-HDAC8 complex

Damaged mitochondria accumulation in diabetes is one of the main features that contribute to increased incidence of cognitive impairment by inducing apoptosis. Butyrate is a major metabolite produced by microbiota that has neuroprotective effects by regulating mitochondrial function. However, detailed mechanisms underlying how butyrate can regulate neuronal mitophagy remain unclear. Here, we examined the regulatory effects of sodium butyrate (NaB) on high glucose-induced mitophagy dysregulation, neuronal apoptosis, and cognitive impairment and its underlying mechanisms in human-induced pluripotent stem cell-derived neurons, SH-SY5Ys, and streptozotocin (STZ)-induced diabetic mice. In our results, diabetic mice showed gut-microbiota dysbiosis, especially a decreased number of butyrate-producing bacteria and reduced NaB plasma concentration. NaB ameliorated high glucose-induced neuronal mitochondrial dysfunction by recovering PRKN/Parkin-mediated mitophagy. High glucose-induced reactive oxygen species (ROS) and -inhibited PRKAA/AMPKα stimulated the RELA/p65-HDAC8 complex, which downregulated PRKN protein expression by binding to the PRKN promoter region. NaB restored PRKN expression by blocking RELA nuclear translocation and directly inhibiting HDAC8 in the nucleus. In addition, HDAC8 overexpression inhibited the positive effect of NaB on high glucose-induced mitophagy dysfunction and neuronal apoptosis. Oral administration of NaB improved cognitive impairment in diabetic mice by restoring mitophagy in the hippocampus. Taken together, NaB ameliorates neuronal mitophagy through PRKN restoration by inhibiting RELA-HDAC8 complexes, suggesting that NaB is an important substance for protecting neuronal apoptosis in diabetes-associated cognitive impairment.

The Combination of Bacillus natto JLCC513 and Ginseng Soluble Dietary Fiber Attenuates Ulcerative Colitis by Modulating the LPS/TLR4/NF-κB Pathway and Gut Microbiota

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) that is currently difficult to treat effectively. Both Bacillus natto (BN) and ginseng-soluble dietary fiber (GSDF) are anti-inflammatory and helps sustain the intestinal barrier. In this study, the protective effects and mechanism of the combination of B. natto JLCC513 and ginseng-soluble dietary fiber (BG) in DSS-induced UC mice were investigated. Intervention with BG worked better than taking BN or GSDF separately, as evidenced by improved disease activity index, colon length, and colon injury and significantly reduced the levels of oxidative and inflammatory factors (LPS, ILs, and TNF-α) in UC mice. Further mechanistic study revealed that BG protected the intestinal barrier integrity by maintaining the tight junction proteins (Occludin and Claudin1) and inhibited the LPS/TLR4/NF-κB pathway in UC mice. In addition, BG increased the abundance of beneficial bacteria such as Bacteroides and Turicibacter and reduced the abundance of harmful bacteria such as Allobaculum in the gut microbiota of UC mice. BG also significantly upregulated genes related to linoleic acid metabolism in the gut microbiota. These BG-induced changes in the gut microbiota of mice with UC were significantly correlated with changes in pathological indices. In conclusion, this study demonstrated that BG exerts protective effect against UC by regulating the LPS/TLR4/NF-κB pathway and the structure and metabolic function of gut microbiota. Thus, BG can be potentially used in intestinal health foods to treat UC.

Gut Microbiome Interactions with Oxidative Stress: Mechanisms and Consequences for Health

Understanding how gut flora interacts with oxidative stress has been the subject of significant research in recent years. There is much evidence demonstrating the existence of the microbiome-oxidative stress interaction. However, the biochemical basis of this interaction is still unclear. In this narrative review, possible pathways of the gut microbiota and oxidative stress interaction are presented, among which genetic underpinnings play an important role. Trimethylamine-N-oxide, mitochondria, short-chain fatty acids, and melatonin also appear to play roles. Moreover, the relationship between oxidative stress and the gut microbiome in obesity, metabolic syndrome, chronic ethanol consumption, dietary supplements, and medications is considered. An investigation of the correlation between bacterial community features and OS parameter changes under normal and pathological conditions might provide information for the determination of new research methods. Furthermore, such research could contribute to establishing a foundation for determining the linkers in the microbiome-OS association.

Efficacy of Probiotic Strains Lactobacillus sakei Probio65 and Lactobacillus plantarum Probio-093 in Management of Obesity: An In Vitro and In Vivo Analysis

The prevalence of obesity, characterized by an excessive accumulation of adipose tissue and adipocyte hypertrophy, presents a major public health challenge. This study investigates the therapeutic potential of two probiotic strains, Lactobacillus sakei Probio65 and Lactobacillus plantarum Probio-093, in the context of obesity. Utilizing 3T3-L1 cell-derived human adipocytes, we assessed Probio65's and Probio-093's capacity to mitigate triglyceride accumulation and influence adipocytokine production in vitro. Subsequently, an in vivo trial with male C57BL/6J mice examined the effects of both probiotic strains on adipose tissue characteristics, body weight, fat mass, and obesity-related gene expression. This study employed both live and ethanol-extracted bacterial cells. The results demonstrated significant reductions in the triglyceride deposition, body weight, and adipose tissue mass in the treated groups (p < 0.05). Furthermore, both strains modulated adipokine profiles by downregulating proinflammatory markers such as PAI-1, leptin, TNF-α, STAMP2, F4/80, resistin, and MCP-1, and upregulating the insulin-sensitive transporter GLUT4 and the anti-inflammatory adiponectin (p < 0.05). Our findings suggest that Lactobacillus sakei Probio65 and Lactobacillus plantarum Probio-093 are promising agents for microbiome-targeted anti-obesity therapies, offering the effective mitigation of obesity and improvement in adipocyte function in a murine model.

Systematic Review: Autism Spectrum Disorder and the Gut Microbiota

Objective

Autism spectrum disorders (ASD) are a varying group of disorders characterized by deficiency in social interaction and restrictive patterns of behavior and interests. While there are several studies focusing on the neuro-psychiatric pathogenesis of ASD, its etiology remains unclear. The role of gut-brain-axis in ASD has been studied increasingly and a correlation between symptoms and the composition of gut microbiota has been documented in various works. Despite this, the significance of individual microbes and their function is still widely unknown. This work aims to elucidate the current knowledge of the interrelations between ASD and the gut microbiota in children based on scientific evidence.

Methods

This is a systematic review done by a literature search focusing on the main findings concerning the gut microbiota composition, interventions targeting the gut microbiota, and possible mechanisms explaining the results in children aged between 2 and 18 years of age.

Results

Most studies in this review found significant differences between microbial communities, while there was notable variation in results regarding diversity indices or taxonomic level abundance. The most consistent results regarding taxa differences in ASD children's gut microbiota were higher levels of Proteobacteria, Actinobacteria and Sutterella compared to controls.

Conclusion

These results show that the gut microbiota of children with ASD is altered compared to one of neurotypically developed children. More research is needed to discover whether some of these features could be used as potential biomarkers for ASD and how the gut microbiota could be targeted in therapeutical interventions.Appeared originally in Acta Psychiatr Scand 2023;148:242-254.

Gastrointestinal and brain barriers: unlocking gates of communication across the microbiota-gut-brain axis

Crosstalk between gut and brain has long been appreciated in health and disease, and the gut microbiota is a key player in communication between these two distant organs. Yet, the mechanisms through which the microbiota influences development and function of the gut-brain axis remain largely unknown. Barriers present in the gut and brain are specialized cellular interfaces that maintain strict homeostasis of different compartments across this axis. These barriers include the gut epithelial barrier, the blood-brain barrier and the blood-cerebrospinal fluid barrier. Barriers are ideally positioned to receive and communicate gut microbial signals constituting a gateway for gut-microbiota-brain communication. In this Review, we focus on how modulation of these barriers by the gut microbiota can constitute an important channel of communication across the gut-brain axis. Moreover, barrier malfunction upon alterations in gut microbial composition could form the basis of various conditions, including often comorbid neurological and gastrointestinal disorders. Thus, we should focus on unravelling the molecular and cellular basis of this communication and move from simplistic framing as 'leaky gut'. A mechanistic understanding of gut microbiota modulation of barriers, especially during critical windows of development, could be key to understanding the aetiology of gastrointestinal and neurological disorders.

Bioenergetic signatures of neurodevelopmental regression

Background: Studies have linked autism spectrum disorder (ASD) to physiological abnormalities including mitochondrial dysfunction. Mitochondrial dysfunction may be linked to a subset of children with ASD who have neurodevelopmental regression (NDR). We have developed a cell model of ASD which demonstrates a unique mitochondrial profile with mitochondrial respiration higher than normal and sensitive to physiological stress. We have previously shown similar mitochondrial profiles in individuals with ASD and NDR. Methods: Twenty-six ASD individuals without a history of NDR (ASD-NoNDR) and 15 ASD individuals with a history of NDR (ASD-NDR) were recruited from 34 families. From these families, 30 mothers, 17 fathers and 5 typically developing (TD) siblings participated. Mitochondrial respiration was measured in peripheral blood mononuclear cells (PBMCs) with the Seahorse 96 XF Analyzer. PBMCs were exposed to various levels of physiological stress for 1 h prior to the assay using 2,3-dimethoxy-1,4-napthoquinone. Results: ASD-NDR children were found to have higher respiratory rates with mitochondria that were more sensitive to physiological stress as compared to ASD-NoNDR children, similar to our cellular model of NDR. Differences in mitochondrial respiration between ASD-NDR and TD siblings were similar to the differences between ASD-NDR and ASD-NoNDR children. Interesting, parents of children with ASD and NDR demonstrated patterns of mitochondrial respiration similar to their children such that parents of children with ASD and NDR demonstrated elevated respiratory rates with mitochondria that were more sensitive to physiological stress. In addition, sex differences were seen in ASD children and parents. Age effects in parents suggested that mitochondria of older parents were more sensitive to physiological stress. Conclusion: This study provides further evidence that children with ASD and NDR may have a unique type of mitochondrial physiology that may make them susceptible to physiological stressors. Identifying these children early in life before NDR occurs and providing treatment to protect mitochondrial physiology may protect children from experiencing NDR. The fact that parents also demonstrate mitochondrial respiration patterns similar to their children implies that this unique change in mitochondrial physiology may be a heritable factor (genetic or epigenetic), a result of shared environment, or both.

Targeting DSS-induced ulcerative colitis: evaluating the therapeutic potential of WPI-stachyose conjugates

The pursuit of food-based alternatives to conventional therapies for ulcerative colitis (UC) demands immediate attention. In prior investigations, we synthesized WPI-stachyose conjugates through the Maillard reaction, identifying them as functional prebiotics. However, their impact on in vivo regulation of gut microbiota remains inadequately explored. To bridge this gap, we delved into the therapeutic effects and mechanisms of WPI-stachyose conjugates as prebiotic-functional components in C57BL/6J mice afflicted with dextran sodium sulfate (DSS)-induced UC. The treatment involving WPI-stachyose conjugates led to significant therapeutic advancements, evident in the reduction of pro-inflammatory cytokine levels and restoration of gut microbiota composition. Noticeable enhancements were observed in UC-associated symptoms, including weight loss, colon length reduction, and tissue damage, notably improving in the treated mice. Remarkably, both the conjugates and the physical combination effectively lowered pro-inflammatory cytokines and oxidative stress, with the conjugates demonstrating enhanced effectiveness. Furthermore, the simultaneous administration of WPI-stachyose conjugates further amplified the presence of beneficial bacteria and elevated short-chain fatty acids, acknowledged for their favorable impact across various conditions. These findings underscore the potential therapeutic application of WPI-stachyose conjugates in addressing DSS-induced UC, offering insights into innovative therapeutic strategies.

The influence of microbiota on ferroptosis in intestinal diseases

Ferroptosis is a distinctive form of iron-dependent necrotic cell death, characterized by excessive lipid peroxidation on cellular membranes and compromised cellular antioxidant defenses. Multiple metabolic pathways, including iron and lipid metabolism, as well as antioxidant systems, contribute to the execution of ferroptosis. The gut microbiota exerts regulatory effects on ferroptosis through its microbial composition, biological functions, and metabolites. Notably, most pathogenic bacteria tend to promote ferroptosis, thereby inducing or exacerbating diseases, while most probiotics have been shown to protect against cell death. Given microbiota colonization in the gut, an intimate association is found between intestinal diseases and microbiota. This review consolidates the essential aspects of ferroptotic processes, emphasizing key molecules and delineating the intricate interplay between gut microbiota and ferroptosis. Moreover, this review underscores the potential utility of gut microbiota modulation in regulating ferroptosis for the treatment of intestinal diseases.

Acetate mitigates cardiac mitochondrial dysfunction in experimental model of polycystic ovarian syndrome by modulating GPCR41/43 and PROKR1

The role of short chain fatty acid, acetate in cardiac mitochondrial dysfunction especially in PCOS individuals is unknown. Therefore, the present study investigated the modulatory role of GPCRs (41 and 43) by acetate on cardiac mitochondrial status in PCOS rat model. Eight-week-old female Wistar rats were randomly allotted into four groups (n = 5). Polycystic ovarian syndrome was induced by administering letrozole (1 mg/kg p.o.) once daily for 21 days, thereafter the animals were treated with 200 mg/kg (oral gavage) of acetate for six weeks. Letrozole-induced PCOS rats showed elevated circulating testosterone and anti-mullerian hormone, with multiple ovarian cysts. In addition, these rats also manifested insulin resistance, hyperinsulinemia, and increased plasma triglyceride (TG), TG/HDLc and decreased HDLc, as well as elevated level of cardiac TG, glycogen, glycogen synthase, and plasma/cardiac NF-kB, TNF-α, and SDF-1. Cardiac MDA and caspase-6 increased, while plasma/cardiac NrF2 decreased in PCOS animals. A decrease in mitochondrial ATP synthase, ATP/AMP ratio, CPT2 and SDH, and increased HDAC2 were observed in PCOS rats with decreased level of GPCR 41 and 43 when compared with control. Immunohistochemical evaluation of cardiac tissue also showed decrease expression of PROKR1 in PCOS rats compared with control rats. However, treatment with acetate reversed these systemic, cardiac and mitochondrial anomalies. The present results suggest the therapeutic benefit of acetate, an HDAC2i against cardiac mitochondrial dysfunction in PCOS rat model, by attenuating cardiac inflammation, oxidative stress and apoptosis and these effects are accompanied by modulation of GPCR41 and 43 as well as increased expression of PROKR1.

The microbiome-gut-brain axis in epilepsy: pharmacotherapeutic target from bench evidence for potential bedside applications

The gut-brain axis augments the bidirectional communication between the gut and brain and modulates gut homeostasis and the central nervous system through the hypothalamic-pituitary-adrenal axis, enteroendocrine system, neuroendocrine system, inflammatory and immune pathways. Preclinical and clinical reports showed that gut dysbiosis might play a major regulatory role in neurological diseases such as epilepsy, Parkinson's, multiple sclerosis, and Alzheimer's disease. Epilepsy is a chronic neurological disease that causes recurrent and unprovoked seizures, and numerous risk factors are implicated in developing epilepsy. Advanced consideration of the gut-microbiota-brain axis can reduce ambiguity about epilepsy pathology, antiepileptic drugs, and effective therapeutic targets. Gut microbiota sequencing analysis reported that the level of Proteobacteria, Verrucomicrobia, Fusobacteria, and Firmicutes was increased and the level of Actinobacteria and Bacteroidetes was decreased in epilepsy patients. Clinical and preclinical studies also indicated that probiotics, ketogenic diet, faecal microbiota transplantation, and antibiotics can improve gut dysbiosis and alleviate seizure by enhancing the abundance of healthy biota. This study aims to give an overview of the connection between gut microbiota, and epilepsy, how gut microbiome changes may cause epilepsy, and whether gut microbiome restoration could be used as a treatment for epilepsy.

The potential mechanism of gut microbiota-microbial metabolites-mitochondrial axis in progression of diabetic kidney disease

Diabetic kidney disease (DKD), has become the main cause of end-stage renal disease (ESRD) worldwide. Lately, it has been shown that the onset and advancement of DKD are linked to imbalances of gut microbiota and the abnormal generation of microbial metabolites. Similarly, a body of recent evidence revealed that biological alterations of mitochondria ranging from mitochondrial dysfunction and morphology can also exert significant effects on the occurrence of DKD. Based on the prevailing theory of endosymbiosis, it is believed that human mitochondria originated from microorganisms and share comparable biological characteristics with the microbiota found in the gut. Recent research has shown a strong correlation between the gut microbiome and mitochondrial function in the occurrence and development of metabolic disorders. The gut microbiome's metabolites may play a vital role in this communication. However, the relationship between the gut microbiome and mitochondrial function in the development of DKD is not yet fully understood, and the role of microbial metabolites is still unclear. Recent studies are highlighted in this review to examine the possible mechanism of the gut microbiota-microbial metabolites-mitochondrial axis in the progression of DKD and the new therapeutic approaches for preventing or reducing DKD based on this biological axis in the future.

The Intertwining Roads between Psychological Distress and Gut Microbiota in Inflammatory Bowel Disease

Inflammatory bowel disease represents one of the most life-altering gastrointestinal pathologies, with its multifactorial nature and unclear physiopathology. The most relevant clinical forms, ulcerative colitis and Crohn's disease, clinically manifest with mild to severe flares and remission periods that alter the patient's social, familial and professional integration. The chronic inflammatory activity of the intestinal wall determines severe modifications of the local environment, such as dysbiosis, enteric endocrine, nervous and immune system disruptions and intestinal wall permeability changes. These features are part of the gastrointestinal ecosystem that modulates the bottom-to-top signaling to the central nervous system, leading to a neurobiologic imbalance and clinical affective and/or behavioral symptoms. The gut-brain link is a bidirectional pathway and psychological distress can also affect the central nervous system, which will alter the top-to-bottom regulation, leading to possible functional digestive symptoms and local inflammatory responses. In the middle of this neuro-gastrointestinal system, the microbiome is a key player, as its activities offer basic functional support for both relays. The present article presents current scientific information that links the pathophysiology and clinical aspects of inflammatory bowel disease and psychiatric symptomatology through the complex mechanism of the gut-brain axis and the modulatory effects of the gut microbiota.

Sodium Butyrate as Key Regulator of Mitochondrial Function and Barrier Integrity of Human Glomerular Endothelial Cells

The gut microbiota has emerged as an important modulator of cardiovascular and renal homeostasis. The composition of gut microbiota in patients suffering from chronic kidney disease (CKD) is altered, where a lower number of bacteria producing short chain fatty acids (SCFAs) is observed. It is known that SCFAs, such as butyrate and acetate, have protective effects against cardiovascular diseases and CKD but their mechanisms of action remain largely unexplored. In the present study, we investigated the effect of butyrate and acetate on glomerular endothelial cells. Human glomerular microvascular endothelial cells (hgMVECs) were cultured and exposed to butyrate and acetate and their effects on cellular proliferation, mitochondrial mass and metabolism, as well as monolayer integrity were studied. While acetate did not show any effects on hgMVECs, our results revealed that butyrate reduces the proliferation of hgMVECs, strengthens the endothelial barrier through increased expression of VE-cadherin and Claudin-5 and promotes mitochondrial biogenesis. Moreover, butyrate reduces the increase in oxygen consumption induced by lipopolysaccharides (LPS), revealing a protective effect of butyrate against the detrimental effects of LPS. Taken together, our data show that butyrate is a key player in endothelial integrity and metabolic homeostasis.

Epigenetic Aberrations in Major Psychiatric Diseases Related to Diet and Gut Microbiome Alterations

Nutrition and metabolism modify epigenetic signatures like histone acetylation and DNA methylation. Histone acetylation and DNA methylation in the central nervous system (CNS) can be altered by bioactive nutrients and gut microbiome via the gut-brain axis, which in turn modulate neuronal activity and behavior. Notably, the gut microbiome, with more than 1000 bacterial species, collectively contains almost three million functional genes whose products interact with millions of human epigenetic marks and 30,000 genes in a dynamic manner. However, genetic makeup shapes gut microbiome composition, food/nutrient metabolism, and epigenetic landscape, as well. Here, we first discuss the effect of changes in the microbial structure and composition in shaping specific epigenetic alterations in the brain and their role in the onset and progression of major mental disorders. Afterward, potential interactions among maternal diet/environmental factors, nutrition, and gastrointestinal microbiome, and their roles in accelerating or delaying the onset of severe mental illnesses via epigenetic changes will be discussed. We also provide an overview of the association between the gut microbiome, oxidative stress, and inflammation through epigenetic mechanisms. Finally, we present some underlying mechanisms involved in mediating the influence of the gut microbiome and probiotics on mental health via epigenetic modifications.

Liposomal Epigallocatechin-3-Gallate for the Treatment of Intestinal Dysbiosis in Children with Autism Spectrum Disorder: A Comprehensive Review

Autism Spectrum Disorder (ASD) is characterized by varying degrees of difficulty in social interaction and communication. These deficits are often associated with gastrointestinal symptoms, indicating alterations in both intestinal microbiota composition and metabolic activities. The intestinal microbiota influences the function and development of the nervous system. In individuals with ASD, there is an increase in bacterial genera such as Clostridium, as well as species involved in the synthesis of branched-chain amino acids (BCAA) like Prevotella copri. Conversely, decreased amounts of Akkermansia muciniphila and Bifidobacterium spp. are observed. Epigallocatechin-3-gallate (EGCG) is one of the polyphenols with the greatest beneficial activity on microbial growth, and its consumption is associated with reduced psychological distress. Therefore, the objective of this review is to analyze how EGCG and its metabolites can improve the microbial dysbiosis present in ASD and its impact on the pathology. The analysis reveals that EGCG inhibits the growth of pathogenic bacteria like Clostridium perfringens and Clostridium difficile. Moreover, it increases the abundance of Bifidobacterium spp. and Akkermansia spp. As a result, EGCG demonstrates efficacy in increasing the production of metabolites involved in maintaining epithelial integrity and improving brain function. This identifies EGCG as highly promising for complementary treatment in ASD.

Novel Lipids to Regulate Obesity and Brain Function: Comparing Available Evidence and Insights from QSAR In Silico Models

Lipid molecules, such as policosanol, ergosterol, sphingomyelin, omega 3 rich phosphatidylcholine, α-tocopherol, and sodium butyrate, have emerged as novel additions to the portfolio of bioactive lipids. In this state-of-the-art review, we discuss these lipids, and their activity against obesity and mental or neurological disorders, with a focus on their proposed cellular targets and the ways in which they produce their beneficial effects. Furthermore, this available information is compared with that provided by in silico Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) models in order to understand the usefulness of these tools for the discovery of new bioactive compounds. Accordingly, it was possible to highlight how these lipids interact with various cellular targets related to the molecule transportation and absorption (e.g., α-tocopherol transfer protein for α-Tocopherol, ATP-binding cassette ABC transporters or Apolipoprotein E for sphingomyelins and phospholipids) or other processes, such as the regulation of gene expression (involving Sterol Regulatory Element-Binding Proteins for ergosterol or Peroxisome Proliferator-Activated Receptors in the case of policosanol) and inflammation (the regulation of interleukins by sodium butyrate). When comparing the literature with in silico Quantitative Structure-Activity Relationship (QSAR) models, it was observed that although they are useful for selecting bioactive molecules when compared in batch, the information they provide does not coincide when assessed individually. Our review highlights the importance of considering a broad range of lipids as potential bioactives and the need for accurate prediction of ADMET parameters in the discovery of new biomolecules. The information presented here provides a useful resource for researchers interested in developing new strategies for the treatment of obesity and mental or neurological disorders.

PRKN/parkin-mediated mitophagy is induced by the probiotics Saccharomyces boulardii and Lactococcus lactis

Mitochondrial impairment is a hallmark feature of neurodegenerative disorders, such as Parkinson disease, and PRKN/parkin-mediated mitophagy serves to remove unhealthy mitochondria from cells. Notably, probiotics are used to alleviate several symptoms of Parkinson disease including impaired locomotion and neurodegeneration in preclinical studies and constipation in clinical trials. There is some evidence to suggest that probiotics can modulate mitochondrial quality control pathways. In this study, we screened 49 probiotic strains and tested distinct stages of mitophagy to determine whether probiotic treatment could upregulate mitophagy in cells undergoing mitochondrial stress. We found two probiotics, Saccharomyces boulardii and Lactococcus lactis, that upregulated mitochondrial PRKN recruitment, phospho-ubiquitination, and MFN degradation in our cellular assays. Administration of these strains to Drosophila that were exposed to paraquat, a mitochondrial toxin, resulted in improved longevity and motor function. Further, we directly observed increased lysosomal degradation of dysfunctional mitochondria in the treated Drosophila brains. These effects were replicated in vitro and in vivo with supra-physiological concentrations of exogenous soluble factors that are released by probiotics in cultures grown under laboratory conditions. We identified methyl-isoquinoline-6-carboxylate as one candidate molecule, which upregulates mitochondrial PRKN recruitment, phospho-ubiquitination, MFN degradation, and lysosomal degradation of damaged mitochondria. Addition of methyl-isoquinoline-6-carboxylate to the fly food restored motor function to paraquat-treated Drosophila. These data suggest a novel mechanism that is facilitated by probiotics to stimulate mitophagy through a PRKN-dependent pathway, which could explain the potential therapeutic benefit of probiotic administration to patients with Parkinson disease.

Regulation of Acetylation States by Nutrients in the Inhibition of Vascular Inflammation and Atherosclerosis

Atherosclerosis (AS) is a chronic metabolic disorder and primary cause of cardiovascular diseases, resulting in substantial morbidity and mortality worldwide. Initiated by endothelial cell stimulation, AS is characterized by arterial inflammation, lipid deposition, foam cell formation, and plaque development. Nutrients such as carotenoids, polyphenols, and vitamins can prevent the atherosclerotic process by modulating inflammation and metabolic disorders through the regulation of gene acetylation states mediated with histone deacetylases (HDACs). Nutrients can regulate AS-related epigenetic states via sirtuins (SIRTs) activation, specifically SIRT1 and SIRT3. Nutrient-driven alterations in the redox state and gene modulation in AS progression are linked to their protein deacetylating, anti-inflammatory, and antioxidant properties. Nutrients can also inhibit advanced oxidation protein product formation, reducing arterial intima-media thickness epigenetically. Nonetheless, knowledge gaps remain when it comes to understanding effective AS prevention through epigenetic regulation by nutrients. This work reviews and confirms the underlying mechanisms by which nutrients prevent arterial inflammation and AS, focusing on the epigenetic pathways that modify histones and non-histone proteins by regulating redox and acetylation states through HDACs such as SIRTs. These findings may serve as a foundation for developing potential therapeutic agents to prevent AS and cardiovascular diseases by employing nutrients based on epigenetic regulation.

Enteric nervous system damage caused by abnormal intestinal butyrate metabolism may lead to functional constipation

Functional constipation (FC) is a high morbidity gastrointestinal disease for which dysfunction in the enteric nervous system is a major pathogenesis mechanism. To enhance our understanding of the involvement of intestinal microbiota and its metabolites in the pathogenesis of FC, we conducted a shotgun metagenomic sequencing analysis of gut microbiota and serum short-chain fatty acids (SCFAs) analysis in 460 Chinese women with different defecation frequencies. We observed that the abundance ofFusobacterium_varium, a butyric acid-producing bacterium, was positively correlated (P = 0.0096) with the frequency of defecation; however, the concentrations of serum butyric acid was negatively correlated (P = 3.51E-05) with defecation frequency. These results were verified in an independent cohort (6 patients with FC and 6 controls). To further study the effects of butyric acid on intestinal nerve cells, we treated mouse intestinal neurons in vitro with various concentrations of butyrate (0.1, 0.5, 1, and 2.5 mM). We found that intestinal neurons treated with 0.5 mM butyrate proliferated better than those in the other treatment groups, with significant differences in cell cycle and oxidative phosphorylation signal pathways. We suggest that the decreased butyrate production resulting from the reduced abundance of Fusobacterium in gut microbiota affects the proliferation of intestinal neurons and the energy supply of intestinal cells. However, with FC disease advancing, the consumption and excretion of butyric acid reduce, leading to its accumulation in the intestine. Moreover, the accumulation of an excessively high amount of butyric acid inhibits the proliferation of nerve cells and subsequently exacerbates the disease.

Application background and mechanism of short-chain fatty acids in sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE) is a frequent brain dysfunction found in sepsis patients, manifesting as delirium, cognitive impairment, and abnormal behaviors. The gut microbiome and short-chain fatty acids (SCFAs) are particularly associated with neuroinflammation in patients with SAE, thus noticeably attracting scholars’ attention. The association of brain function with the gut-microbiota-brain axis was frequently reported. Although the occurrence, development, and therapeutic strategies of SAE have been extensively studied, SAE remains a critical factor in determining the long-term prognosis of sepsis and is typically associated with high mortality. This review concentrated on the interaction of SCFAs with microglia in the central nervous system and discussed the anti-inflammatory and immunomodulatory effects of SCFAs by binding to free fatty acid receptors or acting as histone deacetylase inhibitors. Finally, the prospects of dietary intervention using SCFAs as dietary nutrients in improving the prognosis of SAE were reviewed.

From Dysbiosis to Neurodegenerative Diseases through Different Communication Pathways: An Overview

The microbiome research field has rapidly evolved over the last few decades, becoming a major topic of scientific and public interest. The gut microbiota (GM) is the microbial population living in the gut. The GM has many functions, such as maintaining gut homeostasis and host health, providing defense against enteric pathogens, and involvement in immune system development. Several studies have shown that GM is implicated in dysbiosis and is presumed to contribute to neurodegeneration. This review focuses mainly on describing the connection between the intestinal microbiome alterations (dysbiosis) and the onset of neurodegenerative diseases to explore the mechanisms that link the GM to nervous system health, such as the gut-brain axis, as well as the mitochondrial, the adaptive humoral immunity, and the microvesicular pathways. The gut-brain communication depends on a continuous bidirectional flow of molecular signals exchanged through the neural and the systemic circulation. These pathways represent a possible new therapeutic target against neuroinflammation and neurodegeneration. Progress in this context is desperately needed, considering the severity of most neurodegenerative diseases and the current lack of effective treatments.

Molecular Landscape of Tourette's Disorder

Tourette's disorder (TD) is a highly heritable childhood-onset neurodevelopmental disorder and is caused by a complex interplay of multiple genetic and environmental factors. Yet, the molecular mechanisms underlying the disorder remain largely elusive. In this study, we used the available omics data to compile a list of TD candidate genes, and we subsequently conducted tissue/cell type specificity and functional enrichment analyses of this list. Using genomic data, we also investigated genetic sharing between TD and blood and cerebrospinal fluid (CSF) metabolite levels. Lastly, we built a molecular landscape of TD through integrating the results from these analyses with an extensive literature search to identify the interactions between the TD candidate genes/proteins and metabolites. We found evidence for an enriched expression of the TD candidate genes in four brain regions and the pituitary. The functional enrichment analyses implicated two pathways ('cAMP-mediated signaling' and 'Endocannabinoid Neuronal Synapse Pathway') and multiple biological functions related to brain development and synaptic transmission in TD etiology. Furthermore, we found genetic sharing between TD and the blood and CSF levels of 39 metabolites. The landscape of TD not only provides insights into the (altered) molecular processes that underlie the disease but, through the identification of potential drug targets (such as FLT3, NAALAD2, CX3CL1-CX3CR1, OPRM1, and HRH2), it also yields clues for developing novel TD treatments.

Protective Role of Short-Chain Fatty Acids against Ang- II-Induced Mitochondrial Dysfunction in Brain Endothelial Cells: A Potential Role of Heme Oxygenase 2

OBJECTIVES

Short-chain fatty acids (SCFAs), the main metabolites released from the gut microbiota, are altered during hypertension and obesity. SCFAs play a beneficial role in the cardiovascular system. However, the effect of SCFAs on cerebrovascular endothelial cells is yet to be uncovered. In this study, we use brain endothelial cells to investigate the in vitro effect of SCFAs on heme oxygenase 2 (HO-2) and mitochondrial function after angiotensin II (Ang-II) treatment.

METHODS

Brain human microvascular endothelial cells were treated with Ang-II (500 nM for 24 h) in the presence and absence of an SCFAs cocktail (1 μM; acetate, propionate, and butyrate) and/or HO-2 inhibitor (SnPP 5 μM). At the end of the treatment, HO-2, endothelial markers (p-eNOS and NO production), inflammatory markers (TNFα, NFκB-p50, and -p65), calcium homeostasis, mitochondrial membrane potential, mitochondrial ROS and H2O2, and mitochondrial respiration were determined in all groups of treated cells.

KEY RESULTS

Our data showed that SCFAs rescued HO-2 after Ang-II treatment. Additionally, SCFAs rescued Ang-II-induced eNOS reduction and mitochondrial membrane potential impairment and mitochondrial respiration damage. On the other hand, SCFAs reduced Ang-II-induced inflammation, calcium dysregulation, mitochondrial ROS, and H2O2. All of the beneficial effects of SCFAs on endothelial cells and mitochondrial function occurred through HO-2.

CONCLUSIONS

SCFAs treatment restored endothelial cells and mitochondrial function following Ang-II-induced oxidative stress. SCFAs exert these beneficial effects by acting on HO-2. Our results are opening the door for more studies to investigate the effect the of SCFAs/HO-2 axis on hypertension and obesity-induced cerebrovascular diseases.

Butyrate Supplementation Exacerbates Myocardial and Immune Cell Mitochondrial Dysfunction in a Rat Model of Faecal Peritonitis

Mitochondrial dysfunction and immune cell dysfunction are commonplace in sepsis and are associated with increased mortality risk. The short chain fatty acid, butyrate, is known to have anti-inflammatory effects and promote mitochondrial biogenesis. We therefore explored the immunometabolic effects of butyrate in an animal model of sepsis. Isolated healthy human volunteer peripheral mononuclear cells were stimulated with LPS in the presence of absence of butyrate, and released cytokines measured. Male Wistar rats housed in metabolic cages received either intravenous butyrate infusion or placebo commencing 6 h following faecal peritonitis induction. At 24 h, splenocytes were isolated for high-resolution respirometry, and measurement of mitochondrial membrane potential (MMP), reactive oxygen species (mtROS), and intracellular cytokines (TNF alpha, IL-10) using flow cytometry. Isolated splenocytes from septic and septic butyrate treated rats were stimulated with LPS for 18 h and the effects of butyrate on cytokine release assessed. Ex vivo, butyrate (1.8 mM) reduced LPS-induced TNF alpha (p = 0.019) and IL-10 (p = 0.001) release by human PBMCs. In septic animals butyrate infusion reduced the respiratory exchange ratio (p < 0.001), consistent with increased fat metabolism. This was associated with a reduction in cardiac output (p = 0.001), and increased lactate (p = 0.031) compared to placebo-treated septic animals (p < 0.05). Butyrate treatment was associated with a reduction in splenocyte basal respiration (p = 0.077), proton leak (p = 0.022), and non-mitochondrial respiration (p = 0.055), and an increase in MMP (p = 0.007) and mtROS (p = 0.027) compared to untreated septic animals. Splenocyte intracellular cytokines were unaffected by butyrate, although LPS-induced IL-10 release was impaired (p = 0.039). In summary, butyrate supplementation exacerbates myocardial and immune cell mitochondrial dysfunction in a rat model of faecal peritonitis.

Associations of air PM2.5 level with gut microbiota in Chinese Han preschoolers and effect modification by oxytocin receptor gene polymorphism

Variations in the single nucleotide polymorphisms (SNPs) of the oxytocin receptors (OXTR) indicate individual differences in stress response, social behavior, and psychopathology, but very few paper mentioned OXTR as part of the mechanism linking exposure to air pollution and poor social interactions. The authors investigated the moderating role of Oxytocin receptor (OXTR) rs53576 polymorphism in the relationship between PM_2.5 level and gut microbiota in children, in an attempt to provide some reference for the evidence linking biological and environmental factors to children brain development. The study included 86 healthy Chinese preschoolers (50 males, 36 females) from two campuses of a kindergarten with different air PM_2.5 levels. Atmospheric PM_2.5 values released by air quality monitoring stations where the two campuses are located were collected for 30 days. The genotypes of OXTR rs53576 were determined by PCR and restriction fragment length polymorphism. The gut microbiota situation was evaluated by determining urinary concentrations of short-chain fatty acids. Urinary levels of cortisone and cortisol were determined to assess the impact of air pollution on the HPA axis. Urinary 2'-Deoxy-7,8-dihydro-8-oxoguanosine and 8-oxo-7,8-dihydroguanosine were measured to evaluate the oxidative stress state. The genotype distribution frequency of rs53576 polymorphism was consistent with Hardy-Weinberg equilibrium. The average urinary concentrations of cortisone, cortisol and 8-OHdG in high pollution campus preschoolers were significantly higher than those in low pollution campus preschoolers, while situations were opposite for acetic acid, propionic acid, isobutyric acid, butyric acid and valeric acid. The interaction between OXTR rs53576 and air pollution had a significant effect on urinary acetic acid. Allele G of rs53576 may be a risk factor for gut microbiota disorder caused by air pollution, and children with GA/GG genotype may be more susceptible than those with AA genotype.

Air Pollution and Maximum Temperature Are Associated with Neurodevelopmental Regressive Events in Autism Spectrum Disorder

Neurodevelopmental regression (NDR) is an enigmatic event associated with autism spectrum disorder (ASD) during which a child loses previously acquired skills and develops ASD symptoms. In some, a trigger which precedes the NDR event, such as a fever, can be identified, but in many cases no trigger is obvious. We hypothesize that air pollution (PM_2.5) may trigger NDR, especially in those children without an identified trigger. Average daily PM_2.5, ozone, precipitation and maximum temperature (T_max) were derived from Environmental Protection Agency models and National Oceanic and Atmospheric Administration monitors based on zip-code information from 83 ASD participants during the six-weeks following the onset month of an NDR event and a reference period defined as one year before and one year after the event. Seasonally adjusted logistic regression (LR) and linear mixed models (LMM) compared cases (with a history of NDR) and matched controls (without a history of NDR). LR models found that the risk of NDR was related to higher PM_2.5 during 3 to 6 weeks of the NDR event period, particularly in those without a trigger. Overall, both models converged on NDR being related to a higher PM_2.5 and lower T_max both during the NDR event period as well as the reference period, particularly in those without a known trigger. This temporal pattern suggests that environmental triggers, particularly PM_2.5, could be related to NDR, especially in those without an identifiable trigger. Further studies to determine the underlying biological mechanism of this observation could help better understand NDR and provide opportunities to prevent NDR.

Gastrointestinal symptoms have a minor impact on autism spectrum disorder and associations with gut microbiota and short-chain fatty acids

Children with autism spectrum disorder (ASD) experience gastrointestinal (GI) issues more frequently and severely than children who are typically developing (TD). The connections between gastrointestinal problems, microbiota, and short-chain fatty acids (SCFAs) in ASD are still being debated. We enrolled 90 children, 45 of whom were diagnosed with ASD, and examined the impact of GI disorders on ASD. The six-item GI Severity Index questionnaire was used to evaluate gastrointestinal symptoms, while the Social Responsiveness Scale was used to evaluate autism symptoms. Further, the Children’s Sleep Habits Questionnaire and the Children’s Eating Behavior Questionnaire are used to assess sleep and eating disorders in children. We assessed fecal microbiota by 16S rRNA gene sequencing, and SCFA concentrations by gas chromatography/mass spectrometry. The results revealed that children with ASD exhibited a high rate of gastrointestinal issues (78%), as well as higher rates of social impairment and poor sleeping habits, compared to TD children. However, GI disturbances have a minor impact on autism. In addition, the levels of propionic acid, butyric acid, and valeric acid were significantly higher in the ASD group. Besides, the ASD, TD, and GI subgroups possessed distinct microbiome profiles. These findings suggest that gastrointestinal disturbances have no discernible effect on the core symptoms of autism. Although autism may not cause an increase in GI symptoms directly, alterations in metabolites, such as SCFAs, may cause GI symptoms.

Microbiota mitochondria disorders as hubs for early age-related macular degeneration

Age-related macular degeneration (AMD) is a progressive neurodegenerative disease affecting the central area (macula lutea) of the retina. Research on the pathogenic mechanism of AMD showed complex cellular contribution governed by such risk factors as aging, genetic predisposition, diet, and lifestyle. Recent studies suggested that microbiota is a transducer and a modifier of risk factors for neurodegenerative diseases, and mitochondria may be one of the intracellular targets of microbial signaling molecules. This review explores studies supporting a new concept on the contribution of microbiota-mitochondria disorders to AMD. We discuss metabolic, vascular, immune, and neuronal mechanism in AMD as well as key alterations of photoreceptor cells, retinal pigment epithelium (RPE), Bruch's membrane, choriocapillaris endothelial, immune, and neuronal cells. Special attention was paid to alterations of mitochondria contact sites (MCSs), an organelle network of mitochondria, endoplasmic reticulum, lipid droplets (LDs), and peroxisomes being documented based on our own electron microscopic findings from surgically removed human eyes. Morphometry of Bruch's membrane lipids and proteoglycans has also been performed in early AMD and aged controls. Microbial metabolites (short-chain fatty acids, polyphenols, and secondary bile acids) and microbial compounds (lipopolysaccharide, peptidoglycan, and bacterial DNA)-now called postbiotics-in addition to local effects on resident microbiota and mucous membrane, regulate systemic metabolic, vascular, immune, and neuronal mechanisms in normal conditions and in various common diseases. We also discuss their antioxidant, anti-inflammatory, and metabolic effects as well as experimental and clinical observations on regulating the main processes of photoreceptor renewal, mitophagy, and autophagy in early AMD. These findings support an emerging concept that microbiota-mitochondria disorders may be a crucial pathogenic mechanism of early AMD; and similarly, to other age-related neurodegenerative diseases, new treatment approaches should be targeted at these disorders.

Microbiota-derived metabolites as drivers of gut-brain communication

Alterations in the gut microbiota composition have been associated with a range of neurodevelopmental, neurodegenerative, and neuropsychiatric disorders. The gut microbes transform and metabolize dietary- and host-derived molecules generating a diverse group of metabolites with local and systemic effects. The bi-directional communication between brain and the microbes residing in the gut, the so-called gut-brain axis, consists of a network of immunological, neuronal, and endocrine signaling pathways. Although the full variety of mechanisms of the gut-brain crosstalk is yet to be established, the existing data demonstrates that a single metabolite or its derivatives are likely among the key inductors within the gut-brain axis communication. However, more research is needed to understand the molecular mechanisms underlying how gut microbiota associated metabolites alter brain functions, and to examine if different interventional approaches targeting the gut microbiota could be used in prevention and treatment of neurological disorders, as reviewed herein.Abbreviations:4-EPS 4-ethylphenylsulfate; 5-AVA(B) 5-aminovaleric acid (betaine); Aβ Amyloid beta protein; AhR Aryl hydrocarbon receptor; ASD Autism spectrum disorder; BBB Blood-brain barrier; BDNF Brain-derived neurotrophic factor; CNS Central nervous system; GABA ɣ-aminobutyric acid; GF Germ-free; MIA Maternal immune activation; SCFA Short-chain fatty acid; 3M-4-TMAB 3-methyl-4-(trimethylammonio)butanoate; 4-TMAP 4-(trimethylammonio)pentanoate; TMA(O) Trimethylamine(-N-oxide); TUDCA Tauroursodeoxycholic acid; ZO Zonula occludens proteins.

SCFAs Ameliorate Chronic Postsurgical Pain-Related Cognition Dysfunction via the ACSS2-HDAC2 Axis in Rats

Patients with chronic postsurgical pain (CPSP) frequently exhibit comorbid cognitive deficits. Recent observations have emphasized the critical effects of gut microbial metabolites, like short-chain fatty acids (SCFAs), in regulating cognitive function. However, the underlying mechanisms and effective interventions remain unclear. According to hierarchical clustering and 16S rRNA analysis, over two-thirds of the CPSP rats had cognitive impairment, and the CPSP rats with cognitive impairment had an aberrant composition of gut SCFA-producing bacteria. Then, using feces microbiota transplantation, researchers identified a causal relationship between cognitive-behavioral and microbic changes. Similarly, the number of genera that generated SCFAs was decreased in the feces from recipients of cognitive impairment microbiota. Moreover, treatment with the SCFAs alleviated the cognitive-behavioral deficits in the cognitively compromised pain rats. Finally, we observed that SCFA supplementation improved histone acetylation and abnormal synaptic transmission in the medial prefrontal cortex (mPFC), hippocampal CA1, and central amygdala (CeA) area via the ACSS2 (acetyl-CoA synthetase2)-HDAC2 (histone deacetylase 2) axis. These findings link pain-related cognition dysfunction, gut microbiota, and short-chain fatty acids, shedding fresh insight into the pathogenesis and therapy of pain-associated cognition dysfunction.

Mitochondrial Ultrastructure and Activity Are Differentially Regulated by Glycolysis-, Krebs Cycle-, and Microbiota-Derived Metabolites in Monocytes

Several intermediate metabolites harbour cell-signalling properties, thus, it is likely that specific metabolites enable the communication between neighbouring cells, as well as between host cells with the microbiota, pathogens, and tumour cells. Mitochondria, a source of intermediate metabolites, participate in a wide array of biological processes beyond that of ATP production, such as intracellular calcium homeostasis, cell signalling, apoptosis, regulation of immune responses, and host cell-microbiota crosstalk. In this regard, mitochondria's plasticity allows them to adapt their bioenergetics status to intra- and extra-cellular cues, and the mechanisms driving such plasticity are currently a matter of intensive research. Here, we addressed whether mitochondrial ultrastructure and activity are differentially shaped when human monocytes are exposed to an exogenous source of lactate (derived from glycolysis), succinate, and fumarate (Krebs cycle metabolic intermediates), or butyrate and acetate (short-chain fatty acids produced by intestinal microbiota). It has previously been shown that fumarate induces mitochondrial fusion, increases the mitochondrial membrane potential (Δψ_m), and reshapes the mitochondrial cristae ultrastructure. Here, we provide evidence that, in contrast to fumarate, lactate, succinate, and butyrate induce mitochondrial fission, while acetate induces mitochondrial swelling. These traits, along with mitochondrial calcium influx kinetics and glycolytic vs. mitochondrial ATP-production rates, suggest that these metabolites differentially shape mitochondrial function, paving the way for the understanding of metabolite-induced metabolic reprogramming of monocytes and its possible use for immune-response intervention.

Modern Biomarkers for Autism Spectrum Disorder: Future Directions

Autism spectrum disorder is an increasingly prevalent neurodevelopmental disorder in the world today, with an estimated 2% of the population being affected in the USA. A major complicating factor in diagnosing, treating, and understanding autism spectrum disorder is that defining the disorder is solely based on the observation of behavior. Thus, recent research has focused on identifying specific biological abnormalities in autism spectrum disorder that can provide clues to diagnosis and treatment. Biomarkers are an objective way to identify and measure biological abnormalities for diagnostic purposes as well as to measure changes resulting from treatment. This current opinion paper discusses the state of research of various biomarkers currently in development for autism spectrum disorder. The types of biomarkers identified include prenatal history, genetics, neurological including neuroimaging, neurophysiologic, and visual attention, metabolic including abnormalities in mitochondrial, folate, trans-methylation, and trans-sulfuration pathways, immune including autoantibodies and cytokine dysregulation, autonomic nervous system, and nutritional. Many of these biomarkers have promising preliminary evidence for prenatal and post-natal pre-symptomatic risk assessment, confirmation of diagnosis, subtyping, and treatment response. However, most biomarkers have not undergone validation studies and most studies do not investigate biomarkers with clinically relevant comparison groups. Although the field of biomarker research in autism spectrum disorder is promising, it appears that it is currently in the early stages of development.

Selective Probiotic Treatment Positively Modulates the Microbiota-Gut-Brain Axis in the BTBR Mouse Model of Autism

Recent studies have shown promise for the use of probiotics in modulating behaviour through the microbiota–gut–brain axis. In the present study, we assessed the impact of two probiotic strains in mitigating autism-related symptomology in the BTBR T⁺ Itpr3^tf/J mouse model of autism spectrum disorder (ASD). Male juvenile BTBR mice were randomized into: (1) control, (2) Lr probiotic (1 × 10⁹ CFU/mL Lacticaseibacillus rhamnosus HA-114), and (3) Ls probiotic groups (1 × 10⁹ CFU/mL Ligilactobacillus salivarius HA-118) (n = 18–21/group), receiving treatments in drinking water for 4 weeks. Gut microbiota profiling by 16S rRNA showed Lr, but not Ls supplementation, to increase microbial richness and phylogenetic diversity, with a rise in potential anti-inflammatory and butyrate-producing taxa. Assessing serum and brain metabolites, Lr and Ls supplementation produced distinct metabolic profiles, with Lr treatment elevating concentrations of potentially beneficial neuroactive compounds, such as 5-aminovaleric acid and choline. As mitochondrial dysfunction is often observed in ASD, we assessed mitochondrial oxygen consumption rates in the prefrontal cortex and hippocampus. No differences were observed for either treatment. Both Lr and Ls treatment reduced behavioural deficits in social novelty preference. However, no changes in hyperactivity, repetitive behaviour, and sociability were observed. Results show Lr to impart positive changes along the microbiota–gut–brain axis, exhibiting beneficial effects on selected behaviour, gut microbial diversity, and metabolism in BTBR mice.

Uncovering the Mechanism of the Xingnaojing Injection against Ischemic Stroke Using a Combined Network Pharmacology Approach and Gut Microbiota Analysis

Objective

To explore the brain protection mechanism of Xingnaojing injection (XNJ) against ischemic stroke (IS) by the network pharmacology approach and gut microbiota analysis.

Methods

We used network pharmacology analysis to identify the active components of XNJ and its potential targets against IS and inflammatory bowel disease (IBD) and carried out network analysis, functional annotation, and pathway enrichment analysis. Then, transient middle cerebral artery occlusion (tMCAO) mice model was used to verify the molecular mechanism of XNJ.

Results

36 active compounds were identified from XNJ, and the effect of XNJ against IS was related to the VEGF signaling pathway, NF-kappa B signaling pathway, and gap junction. The effect of XNJ against IBD was related to the T cell receptor signaling pathway, NF-kappa B signaling pathway, and gap junction. In vitro experiments showed that XNJ significantly improved the neurological function of tMCAO mice, reduced the size of cerebral infarction, decreased the permeability of blood-brain barrier (BBB), downregulated the expressions of TLR4, MyD88, and NF-kappa B in the ischemic site, and upregulated the expressions of occludin and ZO-1 in the colon. High-throughput 16S rDNA gene sequencing showed that XNJ upregulated the levels of Akkermansia and downregulated the levels of Flavobacteriaceae, Deferribacteraceae, and Deferribacteres. XNJ increased the concentrations of the short-chain fatty acids (SCFAs) PA (propionate), VA (valerate), IBA (isobutyrate), and IVA (isovalerate) in the feces of the sham germ-free experiment group (SGFEG) mice.

Conclusion

IS causes dysbiosis of some specific bacteria in the gut microbiota. XNJ is an effective treatment for IS, and its mechanism was related to improving intestinal barrier function and regulating intestinal flora and SCFAs. Network pharmacology revealed that XNJ acts through multiple targets and multiple pathways.

Sodium butyrate reverses lipopolysaccharide-induced mitochondrial dysfunction in lymphoblasts

Butyrate is a short-chain fatty acid that is produced by commensal microbes within the intestinal microbiome through fermentation of dietary fibre. Microbial-derived butyrate has been shown to promote immunologic and metabolic homeostasis, in part through its beneficial effects on mitochondrial function, and thus has been proposed as a possible anti-inflammatory therapy. We tested the hypothesis that butyrate could mitigate the decrease in mitochondrial respiration in immune cells under septic conditions as a preliminary step towards better understanding the potential for butyrate as a novel therapy in sepsis. Mitochondrial respiration and content (measured as citrate synthase activity) were compared within four Epstein-Barr virus-transformed lymphoblast (LB) cell lines exposed to either control media or lipopolysaccharide (LPS) 100 ng/ml. Both co-incubation of LBs with LPS + butyrate and treatment with butyrate after LPS stimulation reversed the decrease in mitochondrial respiration observed in LBs exposed to LPS without butyrate. Neither LPS nor butyrate led to significant changes in citrate synthase activity. The preliminary findings support further investigation of a potential mitochondrial-based mechanism through which butyrate may help to mitigate the immuno-inflammatory response in sepsis.

Postnatal baicalin ameliorates behavioral and neurochemical alterations in valproic acid-induced rodent model of autism: The possible implication of sirtuin-1/mitofusin-2/ Bcl-2 pathway

Autism spectrum disorder (ASD) is characterized by pervasive impairments in social communication along with repetitive or stereotyped behaviors. Although its distinctive etiology isn`t completely understood, genetic and environmental risk factors were incriminated. Being a flavonoid of high biomedical value, baicalin was recently verified as an emerging medicinal herb with numerous pharmacological activities. The objective of this study was to investigate the feasible effects of baicalin on valproic acid (VPA)-induced autism regarding its potential mitochondrial modulatory, antioxidant, and antiapoptotic effects. The present study was performed using a rodent model of autism by exposing rat fetuses to VPA on the 12.5th day of gestation. Ten male Wistar rats that were born from control pregnant females were considered as group I (control group). Twenty male Wistar rats that were born from prenatal VPA- treated females were further divided into two groups: Group II (VPA- induced ASD) and group III (VPA + Baicalin). Postnatal baicalin promoted postnatal growth and maturation. In addition, it improved motor development and ameliorated repetitive behavior as well as social deficits in prenatally exposed VPA rats. Moreover, baicalin enhanced neuronal mitochondrial functions as evidenced by elevation of mitochondrial adenosine triphosphate (ATP) level and promotion of mitofusin-2 expression. Furthermore, baicalin elevated sirtuin-1 (SIRT1) level in VPA rats' brain tissues and restored the antioxidant defense mechanisms. Besides, it abrogated the neuronal histopathological changes in the brain tissues. Based on the data herein, baicalin may provide a promising pre-clinical therapeutic line in ASD as a mitochondrial function modulator, antioxidant and anti-apoptotic agent.

Cross-species metabolomic analysis of tau- and DDT-related toxicity

Exposure to the pesticide dichlorodiphenyltrichloroethane (DDT) has been associated with increased risk of Alzheimer's disease (AD), a disease also associated with hyperphosphorylated tau (p-tau) protein aggregation. We investigated whether exposure to DDT can exacerbate tau protein toxicity in Caenorhabditiselegans using a transgenic strain that expresses human tau protein prone to aggregation by measuring changes in size, swim behavior, respiration, lifespan, learning, and metabolism. In addition, we examined the association between cerebrospinal fluid (CSF) p-tau protein-as a marker of postmortem tau burden-and global metabolism in both a human population study and in C. elegans, using the same p-tau transgenic strain. From the human population study, plasma and CSF-derived metabolic features associated with p-tau levels were related to drug, amino acid, fatty acid, and mitochondrial metabolism pathways. A total of five metabolites overlapped between plasma and C. elegans, and four between CSF and C. elegans. DDT exacerbated the inhibitory effect of p-tau protein on growth and basal respiration. In the presence of p-tau protein, DDT induced more curling and was associated with reduced levels of amino acids but increased levels of uric acid and adenosylselenohomocysteine. Our findings in C. elegans indicate that DDT exposure and p-tau aggregation both inhibit mitochondrial function and DDT exposure can exacerbate the mitochondrial inhibitory effects of p-tau aggregation. Further, biological pathways associated with exposure to DDT and p-tau protein appear to be conserved between species.

Central Nervous System Metabolism in Autism, Epilepsy and Developmental Delays: A Cerebrospinal Fluid Analysis

Neurodevelopmental disorders are associated with metabolic pathway imbalances; however, most metabolic measurements are made peripherally, leaving central metabolic disturbances under-investigated. Cerebrospinal fluid obtained intraoperatively from children with autism spectrum disorder (ASD, n = 34), developmental delays (DD, n = 20), and those without known DD/ASD (n = 34) was analyzed using large-scale targeted mass spectrometry. Eighteen also had epilepsy (EPI). Metabolites significantly related to ASD, DD and EPI were identified by linear models and entered into metabolite–metabolite network pathway analysis. Common disrupted pathways were analyzed for each group of interest. Central metabolites most involved in metabolic pathways were L-cysteine, adenine, and dodecanoic acid for ASD; nicotinamide adenine dinucleotide phosphate, L-aspartic acid, and glycine for EPI; and adenosine triphosphate, L-glutamine, ornithine, L-arginine, L-lysine, citrulline, and L-homoserine for DD. Amino acid and energy metabolism pathways were most disrupted in all disorders, but the source of the disruption was different for each disorder. Disruption in vitamin and one-carbon metabolism was associated with DD and EPI, lipid pathway disruption was associated with EPI and redox metabolism disruption was related to ASD. Two microbiome metabolites were also detected in the CSF: shikimic and cis-cis-muconic acid. Overall, this study provides increased insight into unique metabolic disruptions in distinct but overlapping neurodevelopmental disorders.

Time dependent changes in the bioenergetics of peripheral blood mononuclear cells: processing time, collection tubes and cryopreservation effects

OBJECTIVES

Bioenergetic measurements in peripheral blood mononuclear cells (PBMCs) using high-throughput respirometry is a promising minimally invasive approach to studying mitochondrial function in humans. However, optimal methods for collecting PBMCs are not well studied.

METHODS

Bioenergetics and viability were measured across processing delays, tube type and cryopreservation.

RESULTS

Storage of collection tubes on dry ice resulted in unrecoverable samples and using the Cell Preparation Tube (CPT^TM) significantly reduced viability. Thus, storage in Sodium Citrate (NaC) and ethylenediaminetetraacetic acid (EDTA) tubes were studied in detail. Cell viability decreased by 0.5% for each hour the samples remained on wet ice prior to processing while cryopreservation decreased viability by 9.6% with viability remaining stable for about one month in liquid nitrogen. Adenosine triphosphate linked respiration (ALR) and proton-leak respiration (PLR) changed minimally while maximal respiratory capacity (MRC) and reserve capacity (RC) decreased markedly with collection tubes stored on wet ice over 24 hrs. Changes in respiratory parameters were more modest over the first 8 hours. Manipulations to replace media did not attenuate changes in respiratory parameters. Cryopreservation decreased ALR, MRC and RC by 17.20, 95.30 and 54.92 pmol/min, respectively and increased PLR by 2.65 pmol/min. PLR, MRC and RC changed moderately during the first month in liquid nitrogen for freshly frozen PBMCs.

CONCLUSIONS

Our results suggest that bioenergetics in PBMCs vary based on the processing time from specimen collection and preservation method. Changes in bioenergetics can be minimized by processing samples with a minimal time delay. Changes in viability are minimal and may not correspond to changes in bioenergetics.

Butyrate Ameliorates Mitochondrial Respiratory Capacity of The Motor-Neuron-like Cell Line NSC34-G93A, a Cellular Model for ALS

Mitochondrial defects in motor neurons are pathological hallmarks of ALS, a neuromuscular disease with no effective treatment. Studies have shown that butyrate, a natural gut-bacteria product, alleviates the disease progression of ALS mice overexpressing a human ALS-associated mutation, hSOD1^G93A. In the current study, we examined the potential molecular mechanisms underlying the effect of butyrate on mitochondrial function in cultured motor-neuron-like NSC34 with overexpression of hSOD1^G93A (NSC34-G93A). The live cell confocal imaging study demonstrated that 1mM butyrate in the culture medium improved the mitochondrial network with reduced fragmentation in NSC34-G93A cells. Seahorse analysis revealed that NSC34-G93A cells treated with butyrate showed an increase of ~5-fold in mitochondrial Spare Respiratory Capacity with elevated Maximal Respiration. The time-dependent changes in the mRNA level of PGC1α, a master regulator of mitochondrial biogenesis, revealed a burst induction with an early increase (~5-fold) at 4 h, a peak at 24 h (~19-fold), and maintenance at 48 h (8-fold) post-treatment. In line with the transcriptional induction of PGC1α, both the mRNA and protein levels of the key molecules (MTCO1, MTCO2, and COX4) related to the mitochondrial electron transport chain were increased following the butyrate treatment. Our data indicate that activation of the PGC1α signaling axis could be one of the molecular mechanisms underlying the beneficial effects of butyrate treatment in improving mitochondrial bioenergetics in NSC34-G93A cells.

Dynamic and Systemic Perspective in Autism Spectrum Disorders: A Change of Gaze in Research Opens to A New Landscape of Needs and Solutions

The first step for a harmonious bio-psycho-social framework in approaching autism spectrum disorders (ASD) is overcoming the conflict between the biological and the psychosocial perspective. Biological research can provide clues for a correct approach to clinical practice, assuming that it would lead to the conceptualization of a pathogenetic paradigm able to account for epidemiologic and clinical findings. The upward trajectory in ASD prevalence and the systemic involvement of other organs besides the brain suggest that the epigenetic paradigm is the most plausible one. The embryo-fetal period is the crucial window of opportunity for keeping neurodevelopment on the right tracks, suggesting that women's health in pregnancy should be a priority. Maladaptive molecular pathways beginning in utero, in particular, a vicious circle between the immune response, oxidative stress/mitochondrial dysfunction, and dysbiosis-impact neurodevelopment and brain functioning across the lifespan and are the basis for progressive multisystemic disorders that account for the substantial health loss and the increased mortality in ASD. Therefore, the biological complexity of ASD and its implications for health requires the enhancement of clinical skills on these topics, to achieve an effective multi-disciplinary healthcare model. Well-balanced training courses could be a promising starting point to make a change.

Redox signaling, mitochondrial metabolism, epigenetics and redox active phytochemicals

Biological redox signaling plays an important role in many diseases. Redox signaling involves reductive and oxidative mechanisms. Oxidative stress occurs when reductive mechanism underwhelms oxidative challenges. Cellular oxidative stress occurs when reactive oxygen/nitrogen species (RO/NS) exceed the cellular reductive/antioxidant capacity. Endogenously produced RO/NS from mitochondrial metabolic citric-acid-cycle coupled with electron-transport-chain or exogenous stimuli trigger cellular signaling events leading to homeostatic response or pathological damage. Recent evidence suggests that RO/NS also modulate epigenetic machinery driving gene expression. RO/NS affect DNA methylation/demethylation, histone acetylation/deacetylation or histone methylation/demethylation. Many health beneficial phytochemicals possess redox capability that counteract RO/NS either by directly scavenging the radicals or via inductive mechanism of cellular defense antioxidant/reductive enzymes. Amazingly, these phytochemicals also possess epigenetic modifying ability. This review summarizes the latest advances on the interactions between redox signaling, mitochondrial metabolism, epigenetics and redox active phytochemicals and the future challenges of integrating these events in human health.

Nutraceuticals and Physical Activity as Antidepressants: The Central Role of the Gut Microbiota

Major depressive disorder (MDD) is a common mental illness. Evidence suggests that the gut microbiota play an essential role in regulating brain functions and the pathogenesis of neuropsychiatric diseases, including MDD. There are numerous mechanisms through which the gut microbiota and brain can exchange information in a continuous, bidirectional communication. Current research emphasizes the interexchange of signals influenced by the gut microbiota that are detected and transduced in information from the gut to the nervous system involving neural, endocrine, and inflammatory mechanisms, suggesting a relationship between oxidative stress and the pathophysiology of MDD via the hyperactivation of inflammatory responses. Potential sources of inflammation in the plasma and hippocampus of depressed individuals could stem from increases in intestinal permeability. Some nutraceuticals, such as specific probiotics, namely psychobiotics, polyphenols, carotenoids, butyrate, and prebiotics, have been demonstrated to exert an antidepressant activity, but most of them need to be metabolized and activated by gut microorganisms. By inducing changes in the gut microbiota composition, physical exercise might also exert a role in alleviating depression-like symptoms. The mutual relationships among nutraceuticals, exercise, and depression will be discussed, and the potential role of the gut microbiota as a therapeutic target to treat depression will be explored.

The Human Gut Microbiome as a Potential Factor in Autism Spectrum Disorder

The high prevalence of gastrointestinal (GI) disorders among autism spectrum disorder (ASD) patients has prompted scientists to look into the gut microbiota as a putative trigger in ASD pathogenesis. Thus, many studies have linked the gut microbial dysbiosis that is frequently observed in ASD patients with the modulation of brain function and social behavior, but little is known about this connection and its contribution to the etiology of ASD. This present review highlights the potential role of the microbiota–gut–brain axis in autism. In particular, it focuses on how gut microbiota dysbiosis may impact gut permeability, immune function, and the microbial metabolites in autistic people. We further discuss recent findings supporting the possible role of the gut microbiome in initiating epigenetic modifications and consider the potential role of this pathway in influencing the severity of ASD. Lastly, we summarize recent updates in microbiota-targeted therapies such as probiotics, prebiotics, dietary supplements, fecal microbiota transplantation, and microbiota transfer therapy. The findings of this paper reveal new insights into possible therapeutic interventions that may be used to reduce and cure ASD-related symptoms. However, well-designed research studies using large sample sizes are still required in this area of study.