The effect of lead exposure on fatty acid composition in mouse brain analyzed using pseudo-catalytic derivatization

Fermented mixed grain ameliorates chronic stress-induced depression-like behavior and memory deficit

Fermented mixed grain (FG) has beneficial anti-cancer, antioxidant, and anti-inflammatory effects. In this study, we investigated the effects of FG on gut inflammation, brain dysfunction, and anxiety/depression-like behavior induced by unpredictable chronic mild stress (UCMS) in mice. Mice were administered mixed grain or FG for 3 weeks and were then exposed to UCMS for 4 weeks. FG administration ameliorated stress-induced anxiety/despair-like behavior. FG administration also prevented UCMS-induced memory impairment. Additionally, the mRNA levels of 5-HTR1A and IL-6 were restored to normal levels in the brains of FG-administered mice. FG administration also inhibited intestinal damage in stressed mice compared with that in the UCMS (without FG) group. These results suggest that FG can alleviate stress-induced intestinal damage, brain dysfunction, and cognitive impairment.

Lead exposure induced lipid metabolism disorders by regulating the lipophagy process in microglia

Environmental lead (Pb) pollution is a worldwide public health problem and causes various diseases, especially neurodegenerative diseases. It is increasingly recognized that microglia-mediated neuroinflammation plays a crucial role in lead neurotoxicity, but the underlying mechanisms remain to be further explored. Recent studies indicated that cell metabolism, especially lipid metabolism, regulates many microglial functions, including cytokine secretion and phagocytosis. Whether lipid metabolism is involved in Pb-induced neuroinflammation is still unknown. In the current studies, we investigated the effects of Pb on microglial lipid metabolism by utilizing lipidomics. Histochemistry staining and oxygen consumption rate (OCR) were used to validate lipidomics results. Fenofibrate (FEN), a peroxisome proliferator-activated receptor-α (PPAR-α) agonist, was applied to investigate whether lipid metabolism regulation mitigated Pb's neuroinflammatory response. Microglial autophagic proteins were detected to investigate the role of lipophagy in Pb's effect on lipid metabolism. Our results showed that Pb exposure increased concentrations of various lipid metabolites and induced lipid metabolism disorders, especially in fatty acid metabolism. Pb caused lipid droplet (LD) accumulation and slightly enhanced fatty acid oxidation (FAO) in microglia. FEN pretreatment markedly inhibited Pb's effects on LDs and further mitigated Pb-induced inflammatory response by reducing pro-cytokines' expression and enhancing phagocytosis function. FEN intervention also inhibited Pb's neurotoxicity by improving cognition-related behaviors. Pb exposure induced an abnormal increase of autophagic proteins, but the FEN addition partially neutralized Pb's effects on autophagy. Our data indicate that the Pb-induced neuroinflammation is regulated by fatty acid metabolism via the lipophagy process. Therapies focusing on lipid metabolism regulation are powerful tactics in Pb toxicity prevention and treatment.

Bisphenol S Impairs Behaviors through Disturbing Endoplasmic Reticulum Function and Reducing Lipid Levels in the Brain of Zebrafish

The number of neurotoxic pollutants is increasing, but their mechanism of action is unclear. Here, zebrafish were exposed to 0, 1, 10, and 100 μg/L bisphenol S (BPS) for different durations beginning at 2 h postfertilization (hpf) to explore the neurotoxic mechanisms of BPS. Zebrafish larvae exposed to BPS displayed abnormal neurobehaviors. At 48 and 120 hpf, BPS inhibited yolk lipid consumption and reduced the lipid distribution in the zebrafish brain. Moreover, BPS downregulated the mRNA levels of genes involved in fatty acid elongation in the endoplasmic reticulum (ER) and activated ER stress pathways at 48 and 120 hpf, and KEGG analysis after RNA-seq showed that the protein processing pathway in the ER was significantly enriched after BPS exposure. Exposure to ER toxicants (thapsigargin and tunicamycin), two positive controls, induced neurotoxic effects on zebrafish embryos and larvae similar to those of BPS exposure. These data suggested that BPS and ER toxicants disturbed ER function and reduced brain lipid levels. Continued exposure to BPS into adulthood not only inhibited brain fatty acid elongation and ER function but also caused abnormal swelling of the ER in zebrafish. Our data provide new insights into the neurotoxic mechanism of BPS.

Role of metallic pollutants in neurodegeneration: effects of aluminum, lead, mercury, and arsenic in mediating brain impairment events and autism spectrum disorder

Autism spectrum disorder (ASD) is a developmental disorder of the brain characterized by shortfall in the social portfolio of an individual and abbreviated interactive and communication aspects rendering stereotypical behavior and pitfalls in a child's memory, thinking, and learning capabilities. The incidence of ASD has accelerated since the past decade, portraying environment as one of the primary assets, comprising of metallic components aiming to curb the neurodevelopmental pathways in an individual. Many regulations like Clean Air Act and critical steps taken by countries all over the globe, like Sweden and the USA, have rendered the necessity to study the effects of environmental metallic components on ASD progression. The review focuses on the primary metallic components present in the environment (aluminum, lead, mercury, and arsenic), responsible for accelerating ASD symptoms by a set of general mechanisms like oxidative stress reduction, glycolysis suppression, microglial activation, and metalloprotein disruption, resulting in apoptotic signaling, neurotoxic effects, and neuroinflammatory responses. The effect of these metals can be retarded by certain protective strategies like chelation, dietary correction, certain agents (curcumin, mangiferin, selenium), and detoxification enhancement, which can necessarily halt the neurodegenerative effects.

Analysis of fatty acids in mouse tissue via in situ transmethylation with biochar

Lipid derivatization technology-mediated fatty acid profiling studies have been suggested to dissect the contents of lipids in white fat and brown fat tissue. The focus of this study is to profile fatty acid lipidomics in brown adipose tissue and white adipose tissue of mice by derivatizing their lipids into fatty acid methyl esters via in situ transmethylation using a rice husk-derived biochar as porous media. The in situ transmethylation using biochar is advantageous in biological analysis because there was no loss of samples inevitably occurring in the loss of lipid in solvent extraction and purification steps.

Biodiesel synthesis from fish waste via thermally-induced transesterification using clay as porous material

The valorization of organic waste through biodiesel synthesis was investigated to explore the concept of hazardous waste-to-energy. Fish waste (mackerel waste) was chosen as a case study because of the growing concern regarding the treatment of food waste, which is potentially hazardous to the environment. This study focused on the thermally-induced transesterification of fish waste for the production of biodiesel (i.e., fatty acid methyl esters (FAMEs)). This process requires a porous material that allows for the collision between reactants (fish waste and methanol) to increase inside its pores at high temperatures. Therefore, commercial clay (montmorillonite) was used as the porous material in this study. The optimal temperature for the thermally-induced transesterification of unpurified mackerel oil was 380 °C, and the FAME recovery reached up to ˜72 wt.%. This study also proved that thermal cracking of polyunsaturated FAME species was initiated at temperatures ≥390 °C, and that fish waste is a promising feedstock for biodiesel when it is produced via thermally-induced transesterification over clay as a porous material.

Fatty acid levels alterations in THP-1 macrophages cultured with lead (Pb)

OBJECTIVE

As cardiovascular events are one of the main causes of death in developed countries, each factor potentially increasing the risk of cardiovascular disease deserves special attention. One such factor is the potentially atherogenic effect of lead (Pb) on lipid metabolism, and is significant in view of the still considerable Pb environmental pollution and the non-degradability of Pb compounds.

METHODS

Analysis of saturated fatty acids (SFA) (caprylic acid (C8:0), decanoic acid (C10:0), lauric acid (C12:0), tridecanoic acid (C13:0), myristic acid (C14:0), pentadecanoic acid (C15:0), palmitic acid (C16:0), heptadecanoic acid (C17:0), stearic acid (C18:0), and behenic acid (C22:0)), monounsaturated fatty acid (MUFA) (palmitoleic acid (C16:1), oleic acid (18:1w9), trans-vaccenic acid (C18:1 trans11)), and polyunsaturated fatty acid (PUFA) (linoleic acid (C18:2n6), gamma-linolenic acid (C18:3n6), arachidonic acid (C20:4n6)), was conducted by gas chromatography. Analysis of stearoyl-CoA desaturase (SCD), fatty acid desaturase 1 (FADS1) and fatty acid desaturase 2 (FADS2) expression was performed using qRT-PCR. Oxidative stress intensity (malondialdehyde - MDA concentration) was measured using spectrophotometric method. Intracellular generation of reactive oxygen species (ROS) in macrophages was visualized by fluorescence microscopy and quantitatively measured by plate reader.

RESULTS

Pb caused quantitative alterations in FAs profile in macrophages; the effect was Pb-concentration dependent and selective (i.e. concerned only selected FAs). In general, the effect of Pb was biphasic, with Pb levels of 1.25 μg/dL and 2.5 μg/dL being stimulatory, and 10 μg/dL being inhibitory on concentrations of selected FAs. The most potent Pb concentration, resulting in increase in levels of 9 FAs, was 2.5 μg/dL, the Pb-level corresponding to the mean blood Pb concentrations of people living in urban areas not contaminated by Pb. Pb was found to exert similar, biphasic effect on the expression of FADS1. However, Pb decreased, in a concentration-dependent manner, the expression of SCD and FADS2. Pb significantly increased MDA and ROS concentration in macrophages.

CONCLUSION

Environmental Pb exposure might be a risk factor resulting in alterations in FAs levels, oxidative stress and increased MDA concentration in macrophages, which might lead to the formation of foam cells and to inflammatory reactions.

Investigation into role of CO2 in two-stage pyrolysis of spent coffee grounds

As a way of improving process efficiency of pyrolysis of waste biomass, the effect of carbon dioxide (CO₂) on pyrolysis of spent coffee grounds (SCGs) was examined using a two-stage pyrolysis reactor consisting of a region with increasing temperature and an isothermal region. It was experimentally validated that CO₂ accelerates thermal cracking of organic compounds formed during the pyrolysis of SCGs. The expedited thermal cracking attributed to employing CO₂ in pyrolysis of SCGs led to changing pyrolytic products in gas, liquid, and solid phases. The production of gaseous carbon monoxide was increased when using CO₂ as the pyrolysis medium. In liquid pyrolytic products, the formation of phenolic compounds was hindered in the CO₂-assited pyrolysis. Biochar morphology (solid pyrolytic product) was also changed with different pyrolysis environments. This study shows that CO₂ can help improve applicability of pyrolysis of waste biomass by modifying three phase pyrolytic products in a two-stage pyrolyzer.

Toxic metal(loid)-based pollutants and their possible role in autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social interaction, verbal and non-verbal communication, and stereotypic behaviors. Many studies support a significant relationship between many different environmental factors in ASD etiology. These factors include increased daily exposure to various toxic metal-based environmental pollutants, which represent a cause for concern in public health. This article reviews the most relevant toxic metals, commonly found, environmental pollutants, i.e., lead (Pb), mercury (Hg), aluminum (Al), and the metalloid arsenic (As). Additionally, it discusses how pollutants can be a possible pathogenetic cause of ASD through various mechanisms including neuroinflammation in different regions of the brain, fundamentally occurring through elevation of the proinflammatory profile of cytokines and aberrant expression of nuclear factor kappa B (NF-κB). Due to the worldwide increase in toxic environmental pollution, studies on the role of pollutants in neurodevelopmental disorders, including direct effects on the developing brain and the subjects' genetic susceptibility and polymorphism, are of utmost importance to achieve the best therapeutic approach and preventive strategies.

Dietary grape seed proanthocyanidin extract regulates metabolic disturbance in rat liver exposed to lead associated with PPARα signaling pathway

Lead, a pervasive environmental hazard worldwide, causes a wide range of physiological and biochemical destruction, including metabolic dysfunction. Grape seed proanthocyanidin extract (GSPE) is a natural production with potential metabolic regulation in liver. This study was performed to investigate the protective role of GSPE against lead-induced metabolic dysfunction in liver and elucidate the potential molecular mechanism of this event. Wistar rats received GSPE (200 mg/kg) daily with or without lead acetate (PbA, 0.5 g/L) exposure for 56 d. According to biochemical and histopathologic analysis, GSPE attenuated lead-induced metabolic dysfunction, oxidative stress, and liver dysfunction. Liver gene expression profiling was assessed by RNA sequencing and validated by qRT-PCR. Expression of some genes in peroxisome proliferator-activated receptor alpha (PPARα) signaling pathway was significantly suppressed in PbA group and revived in PbA + GSPE group, which was manifested by Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis and validated by western blot analysis. This study supports that dietary GSPE ameliorates lead-induced fatty acids metabolic disturbance in rat liver associated with PPARα signaling pathway, and suggests that dietary GSPE may be a protector against lead-induced metabolic dysfunction and liver injury, providing a novel therapy to protect liver against lead exposure.