Establishment of human cerebral organoid systems to model early neural development and assess the central neurotoxicity of environmental toxins

Human brain development is a complex process,and animal models often have significant limitations.To address this,researchers have developed pluripotent stem cell-derived three-dimensional structures,known as brain-like organoids,to more accurately model early human brain development and disease.To enable more consistent and intuitive reproduction of early brain development,in this study,we incorporated forebrain organoid culture technology into the traditional unguided method of brain organoid culture.This involved embedding organoids in matrigel for only 7 days during the rapid expansion phase of the neural epithelium and then removing them from the matrigel for further cultivation,resulting in a new type of human brain organoid system.This cerebral organoid system replicated the temporospatial characteristics of early human brain development,including neuroepithelium derivation,neural progenitor cell production and maintenance,neuron differentiation and migration,and cortical layer patterning and formation,providing more consistent and reproducible organoids for developmental modeling and toxicology testing.As a proof of concept,we applied the heavy metal cadmium to this newly improved organoid system to test whether it could be used to evaluate the neurotoxicity of environmental toxins.Brain organoids exposed to cadmium for 7 or 14 days manifested severe damage and abnormalities in their neurodevelopmental patterns,including bursts of cortical cell death and premature differentiation.Cadmium exposure caused progressive depletion of neural progenitor cells and loss of organoid integrity,accompanied by compensatory cell proliferation at ectopic locations.The convenience,flexibility,and controllability of this newly developed organoid platform make it a powerful and affordable alternative to animal models for use in neurodevelopmental,neurological,and neurotoxicological studies.

Considerations on the role of environmental toxins in idiopathic Parkinson’s disease pathophysiology

Neurodegenerative diseases are characterized by a progressive dysfunction of the nervous system.Often associated with atrophy of the affected central or peripheral nervous structures,they include diseases such as Parkinson’s Disease(PD),Alzheimer’s Disease and other dementias,Genetic Brain Disorders,Amyotrophic Lateral Sclerosis(ALS or Lou Gehrig’s Disease),Huntington’s Disease,Prion Diseases,and others.The prevalence of neurodegenerative diseases has increased over the last years.This has had a major impact both on patients and their families and has exponentially increased the medical bill by hundreds of billions of Euros.Therefore,understanding the role of environmental and genetic factors in the pathogenesis of PD is crucial to develop preventive strategies.While some authors believe that PD is mainly genetic and that the aging of the society is the principal cause for this increase,different studies suggest that PD may be due to an increased exposure to environmental toxins.In this article we review epidemiological,sociological and experimental studies to determine which hypothesis is more plausible.Our conclusion is that,at least in idiopathic PD(iPD),the exposure to toxic environmental substances could play an important role in its aetiology.

Effect of Change in Rate of Emissions Furan/Dioxin of Public Health Risk on WTE Gede Bage

Bandung, adopted a policy to build Waste to Energy （WTE） systems with a combustion capacity of 500 tons/day. WTE technologies will burn waste that is fed and utilized energy generated to be converted into electrical energy. This technology has the potential to reduce the volume of waste more effectively, but WTE also emit various harmful contaminants, including Polychlorinated Dibenzofurans （PCDF） and Polychlorinated Dibenzo-p-Dioxins （PCDDs）. WTE equipped with air pollution control, so that the emission of harmful contaminants can be controlled and detected continuously. This study only discusses contaminants PCDF and PCDDs, and the effect of air pollution control work against public health risks. In this study, the efficiency of air pollution control is assumed at 0%, 25%, 50%, 75%, 90% and 99%, while the public health risk assessment carried out for the projected 15 years into the future. Public health risk assessment carried out by the calculation of the health risk of carcinogenic （liver cancer）. A causal relationship between the independent variable efficiency of air pollution control with one dependent variable number of liver cancer patients, obtained the simple linear regression equation Y = 76.4592 - 0.7692X.

The interplay of aging,genetics and environmental factors in the pathogenesis of Parkinson’s disease

Background:Parkinson’s disease(PD)is characterized by dopaminergic neuronal loss in the substantia nigra pars compacta and intracellular inclusions called Lewy bodies(LB).During the course of disease,misfoldedα-synuclein,the major constituent of LB,spreads to different regions of the brain in a prion-like fashion,giving rise to successive non-motor and motor symptoms.Etiology is likely multifactorial,and involves interplay among aging,genetic susceptibility and environmental factors.Main body:The prevalence of PD rises exponentially with age,and aging is associated with impairment of cellular pathways which increases susceptibility of dopaminergic neurons to cell death.However,the majority of those over the age of 80 do not have PD,thus other factors in addition to aging are needed to cause disease.Discovery of neurotoxins which can result in parkinsonism led to efforts in identifying environmental factors which may influence PD risk.Nevertheless,the causality of most environmental factors is not conclusively established,and alternative explanations such as reverse causality and recall bias cannot be excluded.The lack of geographic clusters and conjugal cases also go against environmental toxins as a major cause of PD.Rare mutations as well as common variants in genes such as SNCA,LRRK2 and GBA are associated with risk of PD,but Mendelian causes collectively only account for 5%of PD and common polymorphisms are associated with small increase in PD risk.Heritability of PD has been estimated to be around 30%.Thus,aging,genetics and environmental factors each alone is rarely sufficient to cause PD for most patients.Conclusion:PD is a multifactorial disorder involving interplay of aging,genetics and environmental factors.This has implications on the development of appropriate animal models of PD which take all these factors into account.Common converging pathways likely include mitochondrial dysfunction,impaired autophagy,oxidative stress and neuroinflammation,which are associated with the accumulation and spread of misfoldedα-synuclein and neurodegeneration.Understanding the mechanisms involved in the initiation and progression of PD may lead to potential therapeutic targets to prevent PD or modify its course.

Targeted methylation sequencing reveals dysregulated Wnt signaling in Parkinson disease

Parkinson disease（PD） is a progressive neurodegenerative movement disorder. Both environmental and genetic factors play important roles in PD etiology. A number of environmental toxins cause parkinsonism in human and animal models. Genetic studies of rare early onset familial PD cases resulted in identification of disease-linked mutations in multiple genes. Nevertheless, the potential interaction between environment and genetics in PD pathogenesis remains largely unknown. We hypothesized that environmental factors induce abnormal epigenetic regulation that is involved in the pathogenesis of both familial and sporadic PD. We determined the global methylation status of 80,000e110,000 Cp G sites in each of the five sporadic PD patient brains and five age and postmodern interval matched control brains utilizing bisulfite padlock sequencing. Multiple genes involved in neurogenesis, particularly the ones in the Wnt signaling pathway, were hypermethylated in PD brains compared to their matched control brains. Consistent with the DNA methylation changes, marked reduction of protein expression was observed for four Wnt and neurogenesis related genes（FOXC1, NEURG2, SPRY1, and CTNNB1） in midbrain dopaminergic（DA） neurons of PD. The treatment of low concentration of 1-methyl-4-phenylpyridinium（MPPt） for cells resulted in downregulation of Wnt related genes. The study revealed an important link between the epigenetic disregulation of Wnt signaling and the pathogenesis and progression of PD.