Developmental neurotoxic effects of Malathion on 3D neurosphere system

The protective role of resveratrol against sulfoxaflor-induced toxicity in testis of adult male rats

This work was designed to explore the protective role of resveratrol (RES) against sulfoxaflor (Sulfx)-induced reproductive toxicity in adult male rats. The animals were divided into six groups: Control group, Sulfx treated groups (79.5 and 205 mg/kg/day), RES treated group (20 mg/kg/day), RES + Sulfx treated groups (20 mg/kg Res + 79.5 or 205 mg/kg Sulfx) orally for 28 consecutive days. Testicular samples were collected from all groups at the end of the treatment period. Tissue supernatants were isolated for oxidative stress and cellular energy parameters; tissue samples were prepared for histopathological examination. In addition, caspase-3 activity was calculated to assess spermatogenesis. Finally, DNA laddering assay was performed to detect DNA fragmentation as a hallmark of apoptosis. Our results showed that Sulfx treatment induced a significant increase in testicular levels of MDA, NOx, GSSG and reduced GSH level and cellular energy parameters in a dose-dependent manner compared to the control group. The results were confirmed by histopathological study which showed pathological changes in Sulfx treated groups. A significant increase in caspase 3 and DNA fragmentation was also observed. However, concomitant administration of RES to Sulfx -treated rats showed significant modulation against Sulfx-induced reproductive toxicity and attenuated the biochemical, apoptotic and histopathological changes. In conclusion, our results suggest that exposure to Sulfx at the two selected doses induces testicular toxicity and these effects can be ameliorated by supplementation of RES.

Endocrine disruptors also function as nervous disruptors and can be renamed endocrine and nervous disruptors (ENDs)

Endocrine disruption (ED) and endocrine disruptors (EDs) emerged as scientific concepts in 1995, after numerous chemical pollutants were found to be responsible for reproductive dysfunction. The World Health Organization established in the United Nations Environment Programme a list of materials, plasticizers, pesticides, and various pollutants synthesized from petrochemistry that impact not only reproduction, but also hormonal functions, directly or indirectly. Cells communicate via either chemical or electrical signals transmitted within the endocrine or nervous systems. To investigate whether hormone disruptors may also interfere directly or indirectly with the development or functioning of the nervous system through either a neuroendocrine or a more general mechanism, we examined the scientific literature to ascertain the effects of EDs on the nervous system, specifically in the categories of neurotoxicity, cognition, and behaviour. To date, we demonstrated that all of the 177 EDs identified internationally by WHO are known to have an impact on the nervous system. Furthermore, the precise mechanisms underlying this neurodisruption have also been established. It was previously believed that EDs primarily function via the thyroid. However, this study presents substantial evidence that approximately 80 % of EDs operate via other mechanisms. It thus outlines a novel concept: EDs are also neurodisruptors (NDs) and can be collectively termed endocrine and nervous disruptors (ENDs). Most of ENDs are derived from petroleum residues, and their various mechanisms of action are similar to those of "spam" in electronic communications technologies. Therefore, ENDs can be considered as an instance of spam in a biological context.

Neuron and astrocyte aggregation and sorting in three-dimensional neuronal constructs

Aggregation and self-sorting of cells in three dimensional cultures have been described for non-neuronal cells. Despite increased interest in engineered neural tissues for treating brain injury or for modeling neurological disorders in vitro, little data is available on collective cell movements in neuronal aggregates. Migration and sorting of cells may alter these constructs' morphology and, therefore, the function of their neural circuitry. In this work, linear, adhered rat and human 3D neuronal-astrocyte cultures were developed to enable the study of aggregation and sorting of these cells. An in silico model of the contraction, clustering, and cell sorting in the 3D cultures was also developed. Experiments and computational modeling showed that aggregation was mainly a neuron mediated process, and formation of astrocyte-rich sheaths in 3D cultures depended on differential attraction between neurons and astrocytes. In silico model predicted formation of self-assembled neuronal layers in disk-shaped 3D cultures. Neuronal activity patterns were found to correlate with local morphological differences. This model of neuronal and astrocyte aggregation and sorting may benefit future design of neuronal constructs.

Environment permissible concentrations of glyphosate in drinking water can influence the fate of neural stem cells from the subventricular zone of the postnatal mouse

The developing nervous system is highly vulnerable to environmental toxicants especially pesticides. Glyphosate pesticide induces neurotoxicity both in humans and rodents, but so far only when exposed to higher concentrations. A few studies, however, have also reported the risk of general toxicity of glyphosate at concentrations comparable to allowable limits set up by environmental protection authorities. In vitro data regarding glyphosate neurotoxicity at concentrations comparable to maximum permissible concentrations in drinking water is lacking. In the present study, we established an in vitro assay based upon neural stem cells (NSCs) from the subventricular zone of the postnatal mouse to decipher the effects of two maximum permissible concentrations of glyphosate in drinking water on the basic neurogenesis processes. Our results demonstrated that maximum permissible concentrations of glyphosate recognized by environmental protection authorities significantly reduced the cell migration and differentiation of NSCs as demonstrated by the downregulation of the expression levels of the neuronal ß-tubulin III and the astrocytic S100B genes. The expression of the cytoprotective gene CYP1A1 was downregulated whilst the expression of oxidative stresses indicator gene SOD1 was upregulated. The concentration comparable to non-toxic human plasma concentration significantly induced cytotoxicity and activated Ca2+ signalling in the differentiated culture. Our findings demonstrated that the permissible concentrations of glyphosate in drinking water recognized by environmental protection authorities are capable of inducing neurotoxicity in the developing nervous system.

GBA mutation promotes early mitochondrial dysfunction in 3D neurosphere models

Glucocerebrosidase (GBA) mutations are the most important genetic risk factor for the development of Parkinson disease (PD). GBA encodes the lysosomal enzyme glucocerebrosidase (GCase). Loss-of-GCase activity in cellular models has implicated lysosomal and mitochondrial dysfunction in PD disease pathogenesis, although the exact mechanisms remain unclear. We hypothesize that GBA mutations impair mitochondria quality control in a neurosphere model.

We have characterized mitochondrial content, mitochondrial function and macroautophagy flux in 3D-neurosphere-model derived from neural crest stem cells containing heterozygous and homozygous _N370SGBA mutations, under carbonyl cyanide-m-chlorophenyl-hydrazine (CCCP)- induced mitophagy.

Our findings on mitochondrial markers and ATP levels indicate that mitochondrial accumulation occurs in mutant _N370SGBA neurospheres under basal conditions, and clearance of depolarised mitochondria is impaired following CCCP-treatment. A significant increase in TFEB-mRNA levels, the master regulator of lysosomal and autophagy genes, may explain an unchanged macroautophagy flux in _N370SGBA neurospheres. PGC1α-mRNA levels were also significantly increased following CCCP-treatment in heterozygote, but not homozygote neurospheres, and might contribute to the increased mitochondrial content seen in cells with this genotype, probably as a compensatory mechanism that is absent in homozygous lines.

Mitochondrial impairment occurs early in the development of GCase-deficient neurons. Furthermore, impaired turnover of depolarised mitochondria is associated with early mitochondrial dysfunction.

In summary, the presence of GBA mutation may be associated with higher levels of mitochondrial content in homozygous lines and lower clearance of damaged mitochondria in our neurosphere model.

Gestational Exposure to Common Endocrine Disrupting Chemicals and Their Impact on Neurodevelopment and Behavior

Endocrine disrupting chemicals are common in our environment and act on hormone systems and signaling pathways to alter physiological homeostasis. Gestational exposure can disrupt developmental programs, permanently altering tissues with impacts lasting into adulthood. The brain is a critical target for developmental endocrine disruption, resulting in altered neuroendocrine control of hormonal signaling, altered neurotransmitter control of nervous system function, and fundamental changes in behaviors such as learning, memory, and social interactions. Human cohort studies reveal correlations between maternal/fetal exposure to endocrine disruptors and incidence of neurodevelopmental disorders. Here, we summarize the major literature findings of endocrine disruption of neurodevelopment and concomitant changes in behavior by four major endocrine disruptor classes:bisphenol A, polychlorinated biphenyls, organophosphates, and polybrominated diphenyl ethers. We specifically review studies of gestational and/or lactational exposure to understand the effects of early life exposure to these compounds and summarize animal studies that help explain human correlative data.

Effects of prenatal exposure to temephos on behavior and social interaction

The neurodevelopment period is susceptible to alterations by genetic and environmental factors, such as the exposure to organophosphates (OP). The OP is neurotoxic and has been associated with neurological diseases pathophysiology. The OP temephos is widely used against Aedes aegypti in Brazil's public health programs.

PURPOSE

To evaluate behavioral effects of prenatal exposition to temephos in Wistar rats.

METHODS

First, we divided pregnant females into groups: those who received temephos diluted in distilled water by gavage between gestational days 6-13 and those who received only distilled water in the same period and volume. Then, we divided pups according to sex and exposure, and we made the behavioral tests on postnatal day 30.

RESULTS

Prenatal exposure to temephos caused hyperactivity, stereotyped behavior, and social impairment in animals.

CONCLUSION

These results are similar to the altered behavior presented in some neurobiological diseases models, like Attention Deficit Hyperactivity Disorder and Autism Spectrum Disorders, and this study may bring a red alert to the large use of temephos in Brazil, due to the damage caused by its exposure.

Novel putative drugs and key initiating genes for neurodegenerative disease determined using network-based genetic integrative analysis

Understanding the genetic causes of neurodegenerative disease (ND) can be useful for their prevention and treatment. Among the genetic variations responsible for ND, heritable germline variants have been discovered in genome-wide association studies (GWAS), and nonheritable somatic mutations have been discovered in sequencing projects. Distinguishing the important initiating genes in ND and comparing the importance of heritable and nonheritable genetic variants for treating ND are important challenges. In this study, we analysed GWAS results, somatic mutations and drug targets of ND from large databanks by performing directed network-based analysis considering a randomised network hypothesis testing procedure. A disease-associated biological network was created in the context of the functional interactome, and the nonrandom topological characteristics of directed-edge classes were interpreted. Hierarchical network analysis indicated that drug targets tend to lie upstream of somatic mutations and germline variants. Furthermore, using directed path length information and biological explanations, we provide information on the most important genes in these created node classes and their associated drugs. Finally, we identified nine germline variants overlapping with drug targets for ND, seven somatic mutations close to drug targets from the hierarchical network analysis and six crucial genes in controlling other genes from the network analysis. Based on these findings, some drugs have been proposed for treating ND via drug repurposing. Our results provide new insights into the therapeutic actionability of GWAS results and somatic mutations for ND. The interesting properties of each node class and the existing relationships between them can broaden our knowledge of ND.

Engineering principles for guiding spheroid function in the regeneration of bone, cartilage, and skin

There is a critical need for strategies that effectively enhance cell viability and post-implantation performance in order to advance cell-based therapies. Spheroids, which are dense cellular aggregates, overcome many current limitations with transplanting individual cells. Compared to individual cells, the aggregation of cells into spheroids results in increased cell viability, together with enhanced proangiogenic, anti-inflammatory, and tissue-forming potential. Furthermore, the transplantation of cells using engineered materials enables localized delivery to the target site while providing an opportunity to guide cell fate in situ, resulting in improved therapeutic outcomes compared to systemic or localized injection. Despite promising early results achieved by freely injecting spheroids into damaged tissues, growing evidence demonstrates the advantages of entrapping spheroids within a biomaterial prior to implantation. This review will highlight the basic characteristics and qualities of spheroids, describe the underlying principles for how biomaterials influence spheroid behavior, with an emphasis on hydrogels, and provide examples of synergistic approaches using spheroids and biomaterials for tissue engineering applications.

The organophosphate malathion disturbs gut microbiome development and the quorum-Sensing system

The gut microbiome has tremendous potential to impact health and disease. Various environmental toxicants, including insecticides, have been shown to alter gut microbiome community structures. However, the mechanism that compositionally and functionally regulates gut microbiota remains unclear. Quorum sensing is known to modulate intra- and interspecies gene expression and coordinate population responses. It is unknown whether quorum sensing is disrupted when environmental toxicants cause perturbations in the gut microbiome community structure. To reveal the response of the quorum-sensing system to environmental exposure, we use a combination of Illumina-based 16S rRNA gene amplicon and shotgun metagenome sequencing to examine the impacts of a widely used organophosphate insecticide, malathion, on the gut microbiome trajectory, quorum sensing system and behaviors related to quorum sensing, such as motility and pathogenicity. Our results demonstrated that malathion perturbed the gut microbiome development, quorum sensing and quorum sensing related behaviors. These findings may provide a novel mechanistic understanding of the role of quorum-sensing in the gut microbiome toxicity of malathion.