Quantitative proteomics reveals the neurotoxicity of trimethyltin chloride on mitochondria in the hippocampus of mice.

Trimethyltin chloride (TMT) is a potent neurotoxin widely used as a constituent of polyvinyl chloride plastic in the industrial and agricultural fields. However, the underlying mechanisms by which TMT leads to neurotoxicity remain elusive. In the present study, we constructed a dose and time dependent neurotoxic mouse model of TMT exposure to explore the molecular mechanisms involved in TMT-induced neurological damage. Based on this model, the cognitive ability of TMT exposed mice was assessed by the Morris water maze test and a passive avoidance task. The ultrastructure of hippocampus was analyzed by the transmission electron microscope. Subsequently, proteomics integrated with bioinformatics and experimental verification were employed to reveal potential mechanisms of TMT-induced neurotoxicity. Gene ontology (GO) and pathway enrichment analysis were done by using Metascape and GeneCards database respectively. Our results demonstrated that TMT-exposed mice exhibited cognitive disorder, and mitochondrial respiratory chain abnormality of the hippocampus. Proteomics data showed that a total of 7303 proteins were identified in hippocampus of mice of which 224 ones displayed a 1.5-fold increase or decrease in TMT exposed mice compared with controls. Further analysis indicated that these proteins were mainly involved in tricarboxylic acid (TCA) cycle and respiratory electron transport, proteasome degradation, and multiple metabolic pathways as well as inflammatory signaling pathways. Some proteins, including succinate-CoA ligase subunit (Suclg1), NADH dehydrogenase subunit 5 (Nd5), NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 4-like 2 (Ndufa4l2) and cytochrome c oxidase assembly factor 7 (Coa7), which were closely related to mitochondrial respiratory electron transport, showed TMT dose and time dependent changes in the hippocampus of mice. Moreover, apoptotic molecules Bax and cleaved caspase-3 were up-regulated, while anti-apoptotic Bcl-2 was down-regulated compared with controls. In conclusion, our findings suggest that impairment of mitochondrial respiratory chain transport and promotion of apoptosis are the potential mechanisms of TMT induced hippocampus toxicity in mice.

Folic acid ameliorates N-methyl-N'-nitro-N-nitrosoguanidine-induced esophageal inflammation via modulation of the NF-κB pathway.

N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) is a common alkylating agent, which can be experimentally used as a chemical mutagen and carcinogen, extensively existing in the environment. Folic acid (FA), part of the B group of vitamins, plays an important role in defending against inflammation and reducing the risk of cancers. Nevertheless, there is little research on the protective effects of FA against MNNG-induced esophageal inflammation, and its underlying mechanism still remains elusive. Hence, in the present study, we exposed MNNG to SD rats and esophageal cells to establish the esophageal inflammation models. Our research aims to explore the protective roles of FA against esophageal inflammation induced by MNNG via NF-κB pathway by CCK-8, EdU, RT-qPCR, ELISA, H&E, Western blot. Our results revealed that MNNG decreased the viability of esophageal cells, which was restored under FA intervention. Besides, FA relieved the elevation of IL-6, IL-8 and TNF-α in MNNG-induced esophageal inflammation. Moreover, histopathological analysis showed that epithelial spinous cells proliferated in mucous layer, and inflammatory cells were locally infiltrated in the submucosa after MNNG exposure, while the pathological damage of esophageal tissues was gradually alleviated along with increasing FA doses. And Western blot results demonstrated that FA could relieve the rise of phosphorylated IκBα (p-IκBα) and phosphorylated p65 (p-p65) proteins induced by MNNG. Therefore, it is reasonable to believe that FA has a crucial role in preventing MNNG-induced esophageal inflammation through inhibiting the NF-κB pathway, thereby down-regulating the expressions of IL-6, IL-8 and TNF-α.

Copper-catalyzed thiocarbonylation and thiolation of alkyl iodides.

In the present study, an efficient Cu-catalyzed transthiolation of alkyl iodides is developed. Notably, in the presence of CO, thioesters could also be obtained with copper and cobalt as the co-catalyst. This transformation displayed good functional group tolerance and afforded thioesters or sulfides from the corresponding alkyl iodides.