APOE genotype and postnatal chlorpyrifos exposure modulate gut microbiota and cerebral short-chain fatty acids in preweaning mice

The gut-brain axis: Unveiling the impact of xenobiotics on neurological health and disorders

The Gut-Brain Axis (GBA) is a crucial link between the gut microbiota and the central nervous system. Xenobiotics, originating from diverse sources, play a significant role in shaping this interaction. This review examines how these compounds influence neurotransmitter dynamics within the GBA. Environmental pollutants can disrupt microbial populations, impacting neurotransmitter synthesis-especially serotonin, gamma-aminobutyric acid (GABA), and dopamine pathways. Such disruptions affect mood regulation, cognition, and overall neurological function. Xenobiotics also contribute to the pathophysiology of neurological disorders, with changes in serotonin levels linked to mood disorders and imbalances in GABA and dopamine associated with anxiety, stress, and reward pathway disorders. These alterations extend beyond the GBA, leading to complications in neurological health, including increased risk of neurodegenerative diseases due to neuroinflammation triggered by neurotransmitter imbalances. This review provides a comprehensive overview of how xenobiotics influence the GBA and their implications for neurological well-being.

Childhood and adolescent residential and farm pesticide exposures and inflammatory bowel disease incidence in a U.S. cohort of women

BACKGROUND AND AIMS

There are few known risk factors for inflammatory bowel disease (IBD), an autoimmune disease characterized by chronic intestinal inflammation. Use of specific pesticides has been associated with higher incidence of IBD among pesticide applicators and their spouses, but no study has examined pesticide exposure in early life, a period where the human immune system undergoes rapid changes. We evaluated pesticide use during childhood and adolescence and incidence of IBD among US women enrolled in the Sister Study.

METHODS

Incident IBD diagnoses between enrollment (2003-2009) and 2021 were identified and validated with medication use and colectomy/colostomy surgery. We estimated hazard ratios (HR) and 95 % confidence intervals (CI) for the relationship of childhood/adolescent residential and farm pesticide exposures with IBD incidence using Cox models, accounting for age, race and ethnicity, education, smoking, and birth year.

RESULTS

We identified 277 incident IBD cases among 48,382 eligible participants. IBD hazard was elevated among those whose childhood residence was regularly treated with pesticides, especially among those who ever personally applied pesticides (HR = 1.39, 95%CI: 0.65, 2.99). We observed a positive association between IBD and exposure to broadcast pesticide sprays before DDT was banned (>6 times vs. never HR = 1.56, 95%CI: 1.06, 2.31). Among participants who lived on a farm during childhood/adolescence for ≥1 year (N = 9162), IBD hazards were higher among those who were in crop fields during pesticide application (HR = 2.06, 95%CI: 0.94, 4.51) and who ever personally applied pesticides on crops (HR = 1.85, 95%CI: 0.81, 4.18) or livestock (HR = 2.58, 95%CI: 1.14, 5.83).

CONCLUSION

Early-life pesticide exposure may be a novel risk factor for IBD. Practices that reduce pesticide exposure during early life may help reduce the burden of this disease.

Multi-omics and gut microbiome: Unveiling the pathogenic mechanisms of early-life pesticide exposure

The extensive application of pesticides in agricultural production has raised significant concerns about its impact on human health. Different pesticides, including fungicides, insecticides, and herbicides, cause environmental pollution and health problems for non-target organisms. Infants and young children are so vulnerable to the harmful effects of pesticide exposure that early-life exposure to pesticides deserves focused attention. Recent research lays emphasis on understanding the mechanism between negative health impacts and early-life exposure to various pesticides. Studies have explored the impacts of exposure to these pesticides on model organisms (zebrafish, rats, and mice), as well as the mechanism of negative health effects, based on advanced methodologies like gut microbiota and multi-omics. These methodologies help comprehend the pathogenic mechanisms associated with early-life pesticide exposure. In addition to presenting health problems stemming from early-life exposure to pesticides and their pathogenic mechanisms, this review proposes expectations for future research. These proposals include focusing on identifying biomarkers that indicate early-life pesticide exposure, investigating transgenerational effects, and seeking effective treatments for diseases arising from such exposure. This review emphasizes how to understand the pathogenic mechanisms of early-life pesticide exposure through gut microbiota and multi-omics, as well as the adverse health effects of such exposure.

Maternal exposure of mice to glyphosate induces depression- and anxiety-like behavior in the offspring via alterations of the gut-brain axis

The past decade has been characterized by increased awareness and de-stigmatization of mental health issues, in particular the most common neuropsychiatric disorders depression and anxiety. Further, with growing understanding of neurodevelopmental disorders such as attention deficit and hyperactivity disorder and autism spectrum disorder, the number of diagnosed patients has increased. The pathogenesis of these behavioral disorders is multifactorial and early-life exposure to environmental chemicals has been proposed to be a relevant risk factor that might mediate these effects by disturbances on the gut-brain-axis. However, for glyphosate, the most widely used pesticide worldwide, there are only limited and inconsistent findings that link chronic low-dose exposure in particular during early life to neurobehavioral disorders. Here, we explored the impact of maternal oral glyphosate exposure (0.5 and 50 mg/kg body weight/day) during pregnancy and the lactational period on offspring's behavior, brain gene expression and gut microbiota using a cross-generational mouse model. Behavioral analyses revealed a depression- and anxiety-like behavior as well as social deficits most notably in adult female offspring of glyphosate-exposed dams. Furthermore, the expression of tryptophan hydroxylase 2, an enzyme discussed to be linked to behavioral problems, was reduced in the hippocampus of female offspring and correlated to a glyphosate-induced DNA hypermethylation of the gene. Moreover, maternal glyphosate exposure significantly altered the gut microbiota in the female offspring including a decreased abundance of Akkermansia and increased abundance of Alistipes and Blautia, bacteria involved in tryptophan metabolism and associated with depression- and anxiety-like disorders. Our results suggest that glyphosate might influence the gut-brain axis crosstalk following in-utero and lactational exposure. This study underlines the importance of understanding the impact of exposure to pesticides on the gut-brain axis and further emphasizes the need for microbiome analyses to be compulsorily included in health risk assessments of pesticides.

Microbiota-Induced Epigenetic Alterations in Depressive Disorders Are Targets for Nutritional and Probiotic Therapies

Major depressive disorder (MDD) is a complex disorder and a leading cause of disability in 280 million people worldwide. Many environmental factors, such as microbes, drugs, and diet, are involved in the pathogenesis of depressive disorders. However, the underlying mechanisms of depression are complex and include the interaction of genetics with epigenetics and the host immune system. Modifications of the gut microbiome and its metabolites influence stress-related responses and social behavior in patients with depressive disorders by modulating the maturation of immune cells and neurogenesis in the brain mediated by epigenetic modifications. Here, we discuss the potential roles of a leaky gut in the development of depressive disorders via changes in gut microbiota-derived metabolites with epigenetic effects. Next, we will deliberate how altering the gut microbiome composition contributes to the development of depressive disorders via epigenetic alterations. In particular, we focus on how microbiota-derived metabolites such as butyrate as an epigenetic modifier, probiotics, maternal diet, polyphenols, drugs (e.g., antipsychotics, antidepressants, and antibiotics), and fecal microbiota transplantation could positively alleviate depressive-like behaviors by modulating the epigenetic landscape. Finally, we will discuss challenges associated with recent therapeutic approaches for depressive disorders via microbiome-related epigenetic shifts, as well as opportunities to tackle such problems.

Developmental brain lipidomics is influenced by postnatal chlorpyrifos exposure and APOE genetic background in mice

Lipids are a major component of the brain, and are involved in structural and neurodevelopmental processes such as neurogenesis, synaptogenesis and signaling. Apolipoprotein E (apoE) is the main lipoprotein involved in lipid transport in the brain. The apoE isoforms can determine vulnerability to the toxic effects of the pesticide chlorpyrifos (CPF), which can interfere with normal neurodevelopment. We aimed to study the effects of postnatal exposure to CPF and of the APOE genotype on the lipid composition of the brain at early ages. For it, we used apoE3 and apoE4 targeted-replacement (TR) male mice, as well as wild-type C57BL/6. The mice were orally exposed to 1 mg/kg/day of CPF on postnatal days 10-15 and, four hours after the treatment, we obtained samples to assess the cerebral lipid composition. Differences between APOE genotypes were found in the cerebral lipid profile in the postnatal period. ApoE4-TR mice exhibited higher lipid concentrations compared to the other groups in most of the cases. CPF exposure led to a decrease in cholesteryl ester and triglyceride concentrations, while modulating the levels of phosphatidylcholine species based on the apoE isoform. Specifically, CPF treatment decreased the concentration of some species of this lipid (PC30:0, PC31:0, PC32:2, PC36:5, PC40:4 and PC40:5) in C57BL/6 mice exposed to CPF, increased (PC31:0 and PC37:6) in apoE3-TR exposed mice while exposed apoE4-TR mice remained unaltered. These results provide further insights into the lipid composition of the brain at early ages, and how it can be modulated by environmental and genetic factors.

Impact of pesticides exposure during neurodevelopmental period on autism spectrum disorders - A focus on gut microbiota

Accumulating evidence indicates exposure to pesticides during the crucial neurodevelopmental period increases susceptibility to many diseases, including the neurodevelopmental disorder known as autism spectrum disorder (ASD). In the last few years, it has been hypothesized that gut microbiota dysbiosis is strongly implicated in the aetiopathogenesis of ASD. Recently, new studies have suggested that the gut microbiota may be involved in the neurological and behavioural defects caused by pesticides, including ASD symptoms. This review highlights the available evidence from recent animal and human studies on the relationship between pesticides that have the potential to disturb intestinal microbiota homeostasis, and ASD symptoms. The mechanisms through which gut microbiota dysbiosis may trigger ASD-like behaviours induced by pesticides exposure during the neurodevelopmental period via the altered production of bacterial metabolites (short chain fatty acids, lipids, retinol, and amino acid) are also described. According to recent research, gut microbiota dysbiosis may be a major contributor to the symptoms of ASD associated with pesticides exposure. However, to determine the detailed mechanism of action of gut microbiota on pesticide-induced ASD behaviours, actual population exposure scenarios from epidemiological studies should be used as the basis for the appropriate exposure pattern and dosage to be used in animal studies.

Exposure to chlorpyrifos during pregnancy differentially affects social behavior and GABA signaling elements in an APOE- and sex-dependent manner in a transgenic mouse model

The massive use of chlorpyrifos (CPF) has been associated with an increased prevalence of neurodevelopmental disorders. Some previous studies have shown that prenatal, but not postnatal, CPF exposure causes social behavior deficits in mice depending on sex while others have found that in transgenic mice models carrying the human apolipoprotein E (APOE) ε3 and ε4 allele confer different vulnerabilities to either behavioral or metabolic disorders after CPF exposure. This study aims to evaluate, in both sexes, how prenatal CPF exposure and APOE genotype impact on social behavior and its relation to changes in GABAergic and glutamatergic systems. For this purpose, apoE3 and apoE4 transgenic mice were exposed through the diet to 0 or 1 mg/kg/day of CPF, between gestational day 12 and 18. A three-chamber test was used to assess social behavior on postnatal day (PND) 45. Then, mice were sacrificed, and hippocampal samples were analyzed to study the gene expression of GABAergic and glutamatergic elements. Results showed that prenatal exposure to CPF impaired social novelty preference and increased the expression of GABA-A α1 subunit in females of both genotypes. In addition, the expression of GAD1, the ionic cotransporter KCC2 and the GABA-A α2 and α5 subunits were increased in apoE3 mice, whereas CPF treatment only accentuated the expression of GAD1 and KCC2. Nevertheless, future research is needed to evaluate whether the influences detected in the GABAergic system are present and functionally relevant in adults and old mice.

Inactivation of the MSTN gene expression changes the composition and function of the gut microbiome in sheep

Background

Myostatin (MSTN) negatively regulates the muscle growth in animals and MSTN deficient sheep have been widely reported previously. The goal of this study was to explore how MSTN inactivation influences their gut microbiota composition and potential functions.

Results

We compared the slaughter parameters and meat quality of 3 MSTN-edited male sheep and 3 wild-type male sheep, and analyzed the gut microbiome of the MSTN-edited sheep (8 female and 8 male sheep) and wild-type sheep (8 female and 8 male sheep) through metagenomic sequencing. The results showed that the body weight, carcass weight and eye muscle area of MSTN-edited sheep were significantly higher, but there were no significant differences in the meat quality indexes. At the microbial level, the alpha diversity was significantly higher in the MSTN-edited sheep (P < 0.05), and the microbial composition was significantly different by PCoA analysis in the MSTN-edited and wild-type sheep. The abundance of Firmicutes significantly increased and Bacteroidota significantly decreased in the MSTN-edited sheep. At genus level, the abundance of Flavonifractor, Subdoligranulum, Ruthenibacterium, Agathobaculum, Anaerotignum, Oribacterium and Lactobacillus were significantly increased in the MSTN-edited sheep (P < 0.05). Further analysis of functional differences was found that the carotenoid biosynthesis was significantly increased and the peroxisome, apoptosis, ferroptosis, N-glycan biosynthesis, thermogenesis, and adipocytokines pathways were decreased in the MSTN-edited sheep (P < 0.05). Moreover, carbohydrate-active enzymes (CAZymes) results certified the abundance of the GH13_39, GH4, GH137, GH71 and PL17 were upregulated, and the GT41 and CBM20 were downregulated in the MSTN-edited sheep (P < 0.05).

Conclusions

Our study suggested that MSTN inactivation remarkably influenced the composition and potential function of hindgut microbial communities of the sheep, and significantly promoted growth performance without affecting meat quality.

Chronic Effects of Dietary Pesticides on the Gut Microbiome and Neurodevelopment

Many agricultural pesticides include substances that are known to be harmful to human health and while some have been banned from developed countries, they are still being used in developing countries such as Brazil. Recent studies have shown that low-level chronic dietary exposure to pesticides can affect the human gut microbiota. This possible hazardous effect of pesticides on human health has not been specifically recognized by government regulatory agencies. In Brazil, for instance, of the 10 best-selling active ingredients in pesticides in 2019, two are considered extremely toxic, Paraquat and Chlorpyrifos. Even though Paraquat has been banned in Brazil since 2020, the values of maximum residue limits (MRLs) of toxic pesticides allowed in the country are still higher than in other countries. Unfortunately, many developing countries still lack the resources and expertise needed to monitor adequately and systematically the presence of pesticide residues on food. In this work, we raise awareness to the danger the chronic exposure to high dietary levels of pesticides can pose to the public, especially considering their prolonged effects on the gut microbiome.

To the Gut Microbiome and Beyond: The Brain-First or Body-First Hypothesis in Parkinson's Disease

There is continued debate regarding Parkinson’s disease etiology and whether it originates in the brain or begins in the gut. Recently, evidence has been provided for both, with Parkinson’s disease onset presenting as either a “body-first” or “brain-first” progression. Most research indicates those with Parkinson’s disease have an altered gut microbiome compared to controls. However, some studies do not report gut microbiome differences, potentially due to the brain or body-first progression type. Based on the etiology of each proposed progression, individuals with the body-first progression may exhibit altered gut microbiomes, i.e., where short-chain fatty acid producing bacteria are reduced, while the brain-first progression may not. Future microbiome research should consider this hypothesis and investigate whether gut microbiome differences exist between each type of progression. This may further elucidate the impact of the gut microbiome in Parkinson’s disease and show how it may not be homogenous across individuals with Parkinson’s disease.

Impact of Contaminants on Microbiota: Linking the Gut-Brain Axis with Neurotoxicity

Over the last years, research has focused on microbiota to establish a missing link between neuronal health and intestine imbalance. Many studies have considered microbiota as critical regulators of the gut–brain axis. The crosstalk between microbiota and the central nervous system is mainly explained through three different pathways: the neural, endocrine, and immune pathways, intricately interconnected with each other. In day-to-day life, human beings are exposed to a wide variety of contaminants that affect our intestinal microbiota and alter the bidirectional communication between the gut and brain, causing neuronal disorders. The interplay between xenobiotics, microbiota and neurotoxicity is still not fully explored, especially for susceptible populations such as pregnant women, neonates, and developing children. Precisely, early exposure to contaminants can trigger neurodevelopmental toxicity and long-term diseases. There is growing but limited research on the specific mechanisms of the microbiota–gut–brain axis (MGBA), making it challenging to understand the effect of environmental pollutants. In this review, we discuss the biological interplay between microbiota–gut–brain and analyse the role of endocrine-disrupting chemicals: Bisphenol A (BPA), Chlorpyrifos (CPF), Diethylhexyl phthalate (DEHP), and Per- and polyfluoroalkyl substances (PFAS) in MGBA perturbations and subsequent neurotoxicity. The complexity of the MGBA and the changing nature of the gut microbiota pose significant challenges for future research. However, emerging in-silico models able to analyse and interpret meta-omics data are a promising option for understanding the processes in this axis and can help prevent neurotoxicity.

Microbially-derived short-chain fatty acids impact astrocyte gene expression in a sex-specific manner

Recent investigations in neuroscience implicate the role of microbial-derived metabolites, such as short-chain fatty acids (SCFAs) in brain health and disease. The SCFAs acetate, propionate and butyrate have pleiotropic effects within the nervous system. They are crucial for the maturation of the brain's innate immune cells, the microglia, and modulate other glial cells through the aryl-hydrocarbon receptor. Investigations in preclinical and clinical models find that SCFAs exert neuroprotective and antidepressant affects, while also modulating the stress response and satiety. However, many investigations thus far have not assessed the impact of sex on SCFA activity. Our novel investigation tested the impact of physiologically relevant doses of SCFAs on male and female primary cortical astrocytes. We find that butyrate (0–25 ​μM) correlates with increased Bdnf and Pgc1-α expression, implicating histone-deacetylase inhibitor pathways. Intriguingly, this effect is only seen in females. We also find that acetate (0–1500 ​μM) correlates with increased Ahr and Gfap expression in males only, suggesting immune modulatory pathways. In males, propionate (0–35 ​μM) correlates with increased Il-22 expression, further suggesting immunomodulatory actions. These findings show a novel sex-dependent impact of acetate and butyrate, but not propionate on astrocyte gene expression.

Immunoinflammatory role of apolipoprotein E4 in malnutrition and enteric infections and the increased risk for chronic diseases under adverse environments

Apolipoprotein E plays a crucial role in cholesterol metabolism. The immunomodulatory functions of the human polymorphic APOE gene have gained particular interest because APOE4, a well-recognized risk factor for late-onset Alzheimer's disease, has also been recently linked to increased risk of COVID-19 infection severity in a large UK biobank study. Although much is known about apoE functions in the nervous system, much less is known about APOE polymorphism effects on malnutrition and enteric infections and the consequences for later development in underprivileged environments. In this review, recent findings are summarized of apoE's effects on intestinal function in health and disease and the role of APOE4 in protecting against infection and malnutrition in children living in unfavorable settings, where poor sanitation and hygiene prevail, is highlighted. The potential impact of APOE4 on later development also is discussed and gaps in knowledge are identified that need to be addressed to protect children's development under adverse environments.

Genetic and environmental factors in Alzheimer's and Parkinson's diseases and promising therapeutic intervention via fecal microbiota transplantation

Neurodegenerative diseases are characterized by neuronal impairment and loss of function, and with the major shared histopathological hallmarks of misfolding and aggregation of specific proteins inside or outside cells. Some genetic and environmental factors contribute to the promotion of the development and progression of neurodegenerative diseases. Currently, there are no effective treatments for neurodegenerative diseases. It has been revealed that bidirectional communication exists between the brain and the gut. The gut microbiota is a changeable and experience-dependent ecosystem and can be modified by genetic and environmental factors. The gut microbiota provides potential therapeutic targets that can be regulated as new interventions for neurodegenerative diseases. In this review, we discuss genetic and environmental risk factors for neurodegenerative diseases, summarize the communication among the components of the microbiota-gut-brain axis, and discuss the treatment strategy of fecal microbiota transplantation (FMT). FMT is a promising treatment for neurodegenerative diseases, and restoration of the gut microbiota to a premorbid state is a novel goal for prevention and treatment strategies.

Toxicology and Microbiota: How Do Pesticides Influence Gut Microbiota? A Review

In recent years, new targets have been included between the health outcomes induced by pesticide exposure. The gastrointestinal tract is a key physical and biological barrier and it represents a primary site of exposure to toxic agents. Recently, the intestinal microbiota has emerged as a notable factor regulating pesticides’ toxicity. However, the specific mechanisms related to this interaction are not well known. In this review, we discuss the influence of pesticide exposure on the gut microbiota, discussing the factors influencing gut microbial diversity, and we summarize the updated literature. In conclusion, more studies are needed to clarify the host–microbial relationship concerning pesticide exposure and to define new prevention interventions, such as the identification of biomarkers of mucosal barrier function.

NMR-Based Metabolomics Approach to Explore Brain Metabolic Changes Induced by Prenatal Exposure to Autism-Inducing Chemicals

NMR offers the unique potential to holistically screen hundreds of metabolites and has already proved to be a powerful technique able to provide a global picture of a wide range of metabolic processes underlying complex and multifactorial diseases, such as neurodegenerative and neurodevelopmental diseases. The aim of this study was to apply an NMR-based metabolomics approach to explore brain metabolic changes in both male and female rats induced by prenatal exposure to two chemicals associated with autism disorders-the organophosphorus pesticide chlorpyrifos (CPF) and the antiepileptic drug valproic acid (VPA)-at different postnatal ages. Depending on the age and on the brain region (hippocampus and cerebellum), several metabolites were shown to be significantly affected by exposure to both compounds. The evaluation of the spectral profiles revealed that the nervous-system-specific metabolite N-acetylaspartate (NAA), amino acid neurotransmitters (e.g., glutamate, glutamine, GABA, glycine), pyroglutamic acid, unsaturated fatty acids, and choline-based compounds are discriminant biomarkers. Additionally, metabolic changes varied as a function of age, but importantly not of sex.

Chronic oral exposure to pesticides and their consequences on metabolic regulation: role of the microbiota

Pesticides have long been used in agriculture and household treatments. Pesticide residues can be found in biological samples for both the agriculture workers through direct exposure but also to the general population by indirect exposure. There is also evidence of pesticide contamination in utero and trans-generational impacts. Whilst acute exposure to pesticides has long been associated with endocrine perturbations, chronic exposure with low doses also increases the prevalence of metabolic disorders such as obesity or type 2 diabetes. Dysmetabolism is a low-grade inflammation disorder and as such the microbiota plays a role in its etiology. It is therefore important to fully understand the role of microbiota on the genesis of subsequent health effects. The digestive tract and mostly microbiota are the first organs of contact after oral exposure. The objective of this review is thus to better understand mechanisms that link pesticide exposure, dysmetabolism and microbiota. One of the key outcomes on the microbiota is the reduced Bacteroidetes and increased Firmicutes phyla, reflecting both pesticide exposure and risk factors of dysmetabolism. Other bacterial genders and metabolic activities are also involved. As for most pathologies impacting microbiota (including inflammatory disorders), the role of prebiotics can be suggested as a prevention strategy and some preliminary evidence reinforces this axis.

Azadirachtin directly or indirectly affects the abundance of intestinal flora of Spodoptera litura and the energy conversion of intestinal contents mediates the energy balance of intestine-brain axis, and along with decreased expression CREB in the brain neurons

Azadirachtin is a good growth inhibitor for Lepidopteran larvae, but its effect on the brain neurons, intestinal flora and intestinal contents caused by the growth inhibition mechanism has not been reported yet. This study explored the mechanism of azadirachtin on the growth and development of Spodoptera litura larvae and brain neurons through three aspects: intestinal pathology observation, intestinal flora sequencing, and intestinal content analysis. The results showed that the treatment of azadirachtin led to the pathological changes in the structure of the midgut and the goblet cells in the intestinal wall cells to undergo apoptosis. Changes in the host environment of the intestinal flora lead to changes in the abundance value of the intestinal flora, showing an increase in the abundance value of harmful bacteria such as Sphingomonas and Enterococcus, as well as an increase in the abundance value of excellent flora such as Lactobacillus and Bifidobacterium. Changes in the abundance of intestinal flora will result in changes in intestinal contents and metabolites. The test results show that after azadirachtin treatment, the alkane compounds in the intestinal contents of the larvae are greatly reduced, and the number of the long carbon chain and multi-branched hydrocarbon compounds is increased, unsaturated fatty acids, silicon‑oxygen compounds and ethers. The production of similar substances indicates that azadirachtin has an inhibitory effect on digestive enzymes in the intestines, which results in the inhibition of substance absorption and energy transmission, and ultimately the inhibition of larval growth and brain neurons.

Integrated Microbiome and Metabolome Analysis Reveals a Positive Change in the Intestinal Environment of Myostatin Edited Large White Pigs

Myostatin (MSTN) functional inactivation can change the proportion of lean meat and fat content in pigs. While both genotype and microbial composition are known to affect the host phenotype, so far there has been no systematic study to detect the changes in the intestinal microbial composition and metabolome of MSTN single copy mutant pigs. Here, we used 16S rDNA sequencing and metabolome analysis to investigate how MSTN gene editing affects changes in the microbial and metabolome composition in the jejunum and the cecum of Large White pigs. Our results showed that Clostridium_sensu_stricto_1, Bifidobacterium, Lachnospiraceae_UCG-007, Clostridium_sensu_stricto_6, Ruminococcaceae_UCG-002, and Ruminococcaceae_UCG-004 were significantly upregulated; while Treponema_2 and T34_unclassified were significantly downregulated in the jejunum of MSTN pigs. Similarly, Phascolarctobacterium, Ruminiclostridium_9, Succinivibrio, Longibaculum, and Candidatus_Stoquefichus were significantly upregulated, while Barnesiella was significantly downregulated in the cecum of MSTN pigs. Moreover, metabolomics analysis showed significant changes in metabolites involved in purine, sphingolipid and tryptophan metabolism in the jejunum, while those associated with glycerophospholipid and pyrimidine metabolism were changed in the cecum. Spearman correlation analysis further demonstrated that there was a significant correlation between microflora composition and metabolites. Our analyses indicated the MSTN editing affects the composition of metabolites and microbial strains in the jejunum and the cecum, which might provide more useable nutrients for the host of MSTN± Large White pigs.

A comprehensive review on chlorpyrifos toxicity with special reference to endocrine disruption: Evidence of mechanisms, exposures and mitigation strategies

Chlorpyrifos (CPF) is a broad-spectrum chlorinated organophosphate (OP) pesticide used for the control of a variety of insects and pathogens in crops, fruits, vegetables, as well as households, and various other locations. The toxicity of CPF has been associated with neurological dysfunctions, endocrine disruption, and cardiovascular diseases (CVDs). It can also induce developmental and behavioral anomalies, hematological malignancies, genotoxicity, histopathological aberrations, immunotoxicity, and oxidative stress as evidenced by animal modeling. Moreover, eye irritation and dermatological defects are also reported due to CPF toxicity. The mechanism of action of CPF involves blocking the active sites of the enzyme, acetylcholinesterase (AChE), thereby producing adverse nervous system effects. Although CPF has low persistence in the body, its active metabolites, 3,5,6-trichloro-2-pyridinol (TCP), and chlorpyrifos-oxon (CPO) are comparatively more persistent, albeit equally toxic, and thus produce serious health complications. The present review has been compiled taking into account the work related to CPF toxicity and provides a brief compilation of CPF-induced defects in animals and humans, emphasizing the abnormalities leading to endocrine disruption, neurotoxicity, reproductive carcinogenesis, and disruptive mammary gland functionality. Moreover, the clinical signs and symptoms associated with the CPF exposure along with the possible pharmacological treatment are reported in this treatise. Additionally, the effect of food processing methods in reducing CPF residues from different agricultural commodities and dietary interventions to curtail the toxicity of CPF has also been discussed.

Pesticides-induced energy metabolic disorders

Metabolic disorders have become a heavy burden on society. Recently, through excessive use, pesticides have been found to be present in environmental matrixes and sometimes even accumulate in humans or other mammals through the food chain, which then causes health concerns. Evidence has indicated that pesticides have the potential to induce energy metabolic disorders by disturbing the physical process of energy absorption in the intestine and energy storage in the liver, adipose tissue and skeletal muscle in humans or other mammals. In addition, the homeostasis of energy regulation by the pancreas and immune cells is also affected by pesticides. These pesticide-induced disruptions ultimately cause abnormal levels of blood glucose and lipids, which in turn induce the development of related metabolic diseases, including overweight, underweight, insulin resistance and even diabetes. In this review, the results of previous studies focused on the induction of metabolic disorders by pesticides are summarized. We hope that this work will facilitate the discovery of a potential strategy for the treatment of diseases caused by pesticides.

Toxicomicrobiomics: The Human Microbiome vs. Pharmaceutical, Dietary, and Environmental Xenobiotics

The harmful impact of xenobiotics on the environment and human health is being more widely recognized; yet, inter- and intraindividual genetic variations among humans modulate the extent of harm, mostly through modulating the outcome of xenobiotic metabolism and detoxification. As the Human Genome Project revealed that host genetic, epigenetic, and regulatory variations could not sufficiently explain the complexity of interindividual variability in xenobiotics metabolism, its sequel, the Human Microbiome Project, is investigating how this variability may be influenced by human-associated microbial communities. Xenobiotic-microbiome relationships are mutual and dynamic. Not only does the human microbiome have a direct metabolizing potential on xenobiotics, but it can also influence the expression of the host metabolizing genes and the activity of host enzymes. On the other hand, xenobiotics may alter the microbiome composition, leading to a state of dysbiosis, which is linked to multiple diseases and adverse health outcomes, including increased toxicity of some xenobiotics. Toxicomicrobiomics studies these mutual influences between the ever-changing microbiome cloud and xenobiotics of various origins, with emphasis on their fate and toxicity, as well the various classes of microbial xenobiotic-modifying enzymes. This review article discusses classic and recent findings in toxicomicrobiomics, with examples of interactions between gut, skin, urogenital, and oral microbiomes with pharmaceutical, food-derived, and environmental xenobiotics. The current state and future prospects of toxicomicrobiomic research are discussed, and the tools and strategies for performing such studies are thoroughly and critically compared.

Does the perigestational exposure to chlorpyrifos and/or high-fat diet affect respiratory parameters and diaphragmatic muscle contractility in young rats?

The perinatal period is characterized by developmental stages with high sensitivity to environmental factors. Among the risk factors, maternal High-Fat Diet (HFD) consumption and early-life pesticide exposure can induce metabolic disorders at adulthood. We established the effects of perigestational exposure to Chlorpyrifos (CPF) and/or HFD on respiratory parameters, sleep apnea and diaphragm contractility in adult rats. Four groups of female rats were exposed starting from 4 months before gestation till the end of lactation period to CPF (1 mg/kg/day vs. vehicle) with or without HFD. Sleep apnea and respiratory parameters were measured by whole-body plethysmography in male offspring at postnatal day 60. Then diaphragm strips were dissected for the measurement of contractility, acetylcholinesterase (AChE) activity, and gene expression. The perigestational exposure to CPF and/or HFD increased the sleep apnea index but decreased the respiratory frequency. The twitch tension and the fatigability index were also increased, associated with reduced AChE activity and elevated mRNA expression of AChE, ryanodine receptor, and myosin heavy chain isoforms. Therefore, the perigestational exposure to either CPF and/or HFD could program the risks for altered ventilatory parameters and diaphragm contractility in young adult offspring despite the lack of direct contact to CPF and/or HFD.

Neuropathological Mechanisms Associated with Pesticides in Alzheimer's Disease

Environmental toxicants have been implicated in neurodegenerative diseases, and pesticide exposure is a suspected environmental risk factor for Alzheimer’s disease (AD). Several epidemiological analyses have affirmed a link between pesticides and incidence of sporadic AD. Meanwhile, in vitro and animal models of AD have shed light on potential neuropathological mechanisms. In this paper, a perspective on neuropathological mechanisms underlying pesticides’ induction of AD is provided. Proposed mechanisms range from generic oxidative stress induction in neurons to more AD-specific processes involving amyloid-beta (Aβ) and hyperphosphorylated tau (p-tau). Mechanisms that are more speculative or indirect in nature, including somatic mutation, epigenetic modulation, impairment of adult neurogenesis, and microbiota dysbiosis, are also discussed. Chronic toxicity mechanisms of environmental pesticide exposure crosstalks in complex ways and could potentially be mutually enhancing, thus making the deciphering of simplistic causal relationships difficult.