Trimethyltin (TMT) is widely used as a major component of plastic stabilizers in agriculture and industry, and can accumulate in large quantities in the liver. To investigate the relationship between liver tissue damage induced by TMT exposure and YAP phosphorylation in mice, we gave the mice drinking water containing 0.01 mg/mL TMT for 14 days to establish an in vivo experimental model, and continuously treated AML12 cells with 20 μM TMT for 24 h to establish an in vitro experimental model. Transcriptomics revealed that TMT exposure altered 62,466 apparently diversely expressed genes, including 1197 upregulated and 899 downregulated genes, and that enrichment of the Hippo pathway occurred. Moreover, western blotting (WB) and quantitative real-time PCR (qRTPCR) results showed that TMT exposure triggered an increase in the expression of P-YAP, apoptosis and necroptosis-interrelated genes, and a decrease in Bcl-2 expression in mouse livers tissues and AML12 cells. The expression of P-YAP was significantly suppressed in the TRULI-treated TMT-exposed AML12 cells, while oxidative stress levels and damage were also significantly attenuated. In conclusion, TMT triggers YAP phosphorylation to induce oxidative stress inducing apoptosis and necroptosis in mouse livers tissues. Our results confirm the liver toxic effect and specific mechanism of TMT.

Trimethyltin (TMT) is widely used in industry and agriculture. The present study aims to clarify the effects of in vitro TMT exposure on androgen biosynthesis and metabolism in immature Leydig cells (ILCs), and to unveil the underlying mechanism. It was found that 1-10μM TMT decreased ILC androgen productions under basal conditions. TMT at 10μM decreased luteinizing hormone (LH) or 8-Br-cAMP (8BR)-stimulated androgen productions from ILCs. TMT at 10μM decreased 22R-hydroxycholesterol (22R) and androstenedione (D4)-mediated androgen productions from ILCs. TMT at 0.1-10μM down-regulated the mRNA or protein expression levels of STAR, CYP11A1, 17β-HSD3, or NR5A1. TMT at 10μM directly inhibited the enzyme activities of CYP11A1 and 17β-HSD3. In conclusion, the present study demonstrated that in vitro TMT exposure decreased ILC function of androgen production, via exerting negative effects on the mRNA/protein expression levels, or enzyme activities of STAR, CYP11A1, 17β-HSD3, or NR5A1.

Trimethyltin chloride (TMT) is widely used as a constituent of fungicides and plastic stabilizers in the industrial and agricultural fields, and is generally acknowledged to have potent neurotoxicity, especially in the hippocampus; however, the mechanism of induction of neurotoxicity by TMT remains elusive. Herein, we exposed Neuro-2a cells to different concentrations of TMT (2, 4, and 8 μM) for 24 h. Proteomic analysis, coupled with bioinformatics analysis, revealed the important role of macroautophagy/autophagy-lysosome machinery in TMT-induced neurotoxicity. Further analysis indicated significant impairment of autophagic flux by TMT via suppressed lysosomal function, such as by inhibiting lysosomal proteolysis and changing the lysosomal pH, thereby contributing to defects in autophagic clearance and subsequently leading to nerve cell death. Mechanistically, molecular interaction networks of Ingenuity Pathway Analysis identified a downregulated molecule, KIF5A (kinesin family member 5A), as a key target in TMT-impaired autophagic flux. TMT decreased KIF5A protein expression, disrupted the interaction between KIF5A and lysosome, and impaired lysosomal axonal transport. Moreover, Kif5a overexpression restored axonal transport, increased lysosomal dysfunction, and antagonized TMT-induced neurotoxicity in vitro. Importantly, in TMT-administered mice with seizure symptoms and histomorphological injury in the hippocampus, TMT inhibited KIF5A expression in the hippocampus. Gene transfer of Kif5a enhanced autophagic clearance in the hippocampus and alleviated TMT-induced neurotoxicity in vivo. Our results are the first to demonstrate KIF5A-dependent axonal transport deficiency to cause autophagic flux impairment via disturbance of lysosomal function in TMT-induced neurotoxicity; manipulation of KIF5A may be a therapeutic approach for antagonizing TMT-induced neurotoxicity.Abbreviations: 3-MA: 3-methyladenine; AAV: adeno-associated virus; ACTB: actin beta; AGC: automatic gain control; ATG: autophagy-related; ATP6V0D1: ATPase H+ transporting lysosomal V0 subunit D1; ATP6V1E1: ATPase H+ transporting lysosomal V1 subunit E1; CA: cornu ammonis; CQ: chloroquine; CTSB: cathepsin B; CTSD: cathepsin D; DCTN1: dynactin subunit 1; DG: dentate gyrus; DYNLL1: dynein light chain LC8-type 1; FBS: fetal bovine serum; GABARAP: GABA type A receptor-associated protein; GABARAPL1: GABA type A receptor associated protein like 1; GABARAPL2: GABA type A receptor associated protein like 2; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; IPA: Ingenuity Pathway Analysis; KEGG: Kyoto Encyclopedia of Genes and Genomes; KIF5A: kinesin family member 5A; LAMP: lysosomal-associated membrane protein; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; NBR1: NBR1 autophagy cargo receptor; OPTN: optineurin; PBS: phosphate-buffered saline; PFA: paraformaldehyde; PIK3C3/VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; PRM: parallel reaction monitoring; siRNA: small interfering RNA; SQSTM1/p62: sequestosome 1; SYP: synaptophysin; TAX1BP1: Tax1 binding protein 1; TMT: trimethyltin chloride; TUB: tubulin.

Trimethyltin (TMT) is widely used as a plastic heat stabilizer and can cause severe toxicity. Here, the effects of TMT on testosterone production by adult Leydig cells and the related mechanisms of action were investigated. Eighteen adult male Sprague Dawley rats (56 days old) were randomly divided into 3 groups and given intraperitoneal injection of TMT for 21 consecutive days at the doses of 0 (vehicle control), 5, or 10 mg/kg/d. After treatment, trunk blood was collected for hormonal analysis. In addition, related gene and protein expression in testes was detected. At 10 mg/kg, TMT significantly reduced serum testosterone levels but increased serum luteinizing and follicle-stimulating hormone levels. The messenger RNA and protein levels of luteinizing hormone/chorionic gonadotropin receptor, steroidogenic acute regulatory protein, cytochrome P450 17-hydroxylase/17,20-lyase, follicle-stimulating hormone receptor, and SRY box 9 were significantly lower in the TMT-treated testes than in controls. Immunohistochemical study showed that TMT decreased adult Leydig cell number. In conclusion, these findings indicate that TMT reduced adult Leydig cell testosterone production in vivo by directly downregulating the expression of steroidogenic enzymes and decreasing adult Leydig cell number in the testis.

Trimethyltin chloride (TMT) is a potent neurotoxin that causes neuroinflammation and neuronal cell death. Melatonin is a well-known anti-inflammatory agent with significant neuroprotective activity. Male C57BL/6J mice were intraperitoneally injected with a single dose of melatonin (10 mg/kg) before exposure to TMT (2.8 mg/kg, ip). Thereafter, the mice received melatonin (10 mg/kg, ip) once a day for another three consecutive days. Melatonin dramatically alleviated TMT-induced neurotoxicity in mice by attenuating hippocampal neuron loss, inhibiting epilepsy-like seizures, and ameliorating memory deficits. Moreover, melatonin markedly suppressed TMT-induced neuroinflammatory responses and astrocyte activation, as shown by a decrease in inflammatory cytokine production as well as the downregulation of neurotoxic reactive astrocyte phenotype markers. Mechanistically, serine peptidase inhibitor clade A member 3N (SERPINA3N) was identified as playing a central role in the protective effects of melatonin based on quantitative proteome and bioinformatics analysis. Most importantly, melatonin significantly suppressed TMT-induced SERPINA3N upregulation at both the mRNA and protein levels. The overexpression of Serpina3n in the mouse hippocampus abolished the protective effects of melatonin on TMT-induced neuroinflammation and neurotoxicity. Melatonin protected cells against TMT-induced neurotoxicity by inhibiting SERPINA3N-mediated neuroinflammation. Melatonin may be a promising and practical agent for reducing TMT-induced neurotoxicity in clinical practice.

Trimethyltin (TMT), a neurotoxic organotin compound, is selectively localized within the limbic system. The mechanisms of TMT-induced hippocampal neurodegeneration include inflammatory responses, oxidative stress, and neuronal death. Increasing evidence shows that the inflammatory response, mediated by activated inflammasomes, is involved in apoptosis and cellular dysfunction during brain injury. This study aimed to assess the role of the nucleotide-binding oligomerization domain-like receptor pyrin-domain-containing protein 3 (NLRP3) inflammasome in TMT-induced central nervous system (CNS) injury. In addition, the mechanisms underlying TMT neurotoxicity are similar to those involved in the pathogenesis of multiple neurodegenerative diseases; hence, a study on TMT cytotoxicity may be informative for the understanding of human CNS diseases. Microglia were significantly activated in the rat hippocampal dentate gyrus after TMT treatment. The mRNA expression of pro-inflammatory cytokines, interleukin-1β and interleukin-18, was induced both in vitro and in vivo. TMT treatment activated the NLRP3 inflammasome in the microglial cell line BV2. NLRP3 RNA interference significantly protected these cells from TMT-induced neuroinflammation. Our results demonstrate that the NLRP3 inflammasome is a key mediator of neuroinflammation and plays an important role in TMT-induced neuroinflammation.

Trimethyltin (TMT) is an occupational and environmental health hazard behaving as a potent neurotoxin known to affect the central nervous system as well as the peripheral auditory system. However, the mechanisms underlying TMT-induced ototoxicity are poorly understood. To elucidate the effects of TMT on the cochlea, a single injection of 4 or 8 mg/kg TMT was administered intraperitoneally to adult rats. The compound action potential (CAP) threshold was used to assess the functional status of the cochlea and histological techniques were used to assess the condition of the hair cells and auditory nerve fibers. TMT at 4 mg/kg produced a temporary CAP threshold elevation of 25-60 dB that recovered by 28 d post-treatment. Although there was no hair cell loss with the 4 mg/kg dose, there was a noticeable loss of auditory nerve fibers particularly beneath the inner hair cells. TMT at 8 mg/kg produced a large permanent CAP threshold shift that was greatest at the high frequencies. The CAP threshold shift was associated with the loss of outer hair cells and inner hair cells in the basal, high-frequency region of the cochlea, considerable loss of auditory nerve fibers and a significant loss of spiral ganglion neurons in the basal turn. Spiral ganglion neurons showed evidence of soma shrinkage and nuclear condensation and fragmentation, morphological features of apoptotic cell death. TMT-induced damage was greatest in the high-frequency, basal region of the cochlea and the nerve fibers beneath the inner hair cells were the most vulnerable structures.

Trimethyltin (TMT) is a potent neurotoxicant that affects various regions within the central nervous system, including the neocortex, cerebellum, and hippocampus. In the present study, ginsenoside Rd was investigated as a candidate neuroprotective agent in a primary hippocampal neuron culture and mouse models. TMT induced neurotoxicity in a seven-day primary hippocampal neuron culture in a dose-dependent manner (2.5-10 µM). However, pre-treatment with 20 µg/ml ginsenoside Rd for 24 h reversed the toxic action. ICR mice were administered a single injection of 2 mg/kg body weight TMT. Apparent tremor seizure and impaired passive avoidance tests demonstrated significant differences when compared with a saline treated control group. Nissl staining was performed to evaluate the neuronal loss in the hippocampus. In addition, immunostaining of glial fibrillary acidic protein characterized the features of astroglial activation. These results demonstrated that TMT markedly induced Cornu Ammonis 1 subregion neuronal loss and reactive astrocytes in the hippocampus, indicating disrupted hippocampal function. Notably, ginsenoside Rd attenuated the tremor seizures and cognitive decline in behavioral tests. Additionally, significantly reduced neuronal loss (P=0.018) and active astroglials (P=0.003) were observed in the ginsenoside Rd treated group. Ginsenoside Rd prevented TMT-induced cell apoptosis via regulation of B-cell lymphoma 2 (Bcl-2), bcl-2-like protein 4 and caspase-3. These results demonstrate that ginsenoside may be developed as a neuroprotective agent to prevent TMT-induced neurotoxicity.

As ubiquitous environmental toxicants, organotin (IV) compounds (OTC) accumulate in the food chain and potential effects on human health are disquieting. The present study compared the cytotoxicity of three diorganotins, namely, dimethyltin (DMT), dibutyltin (DBT) and diphenyltin (DPT), in rat pheochromocytoma (PC12) cells, and the molecular mechanisms responsible for their cytotoxic effects were also explored. Twenty-four hours exposure of PC12 cells to DBT and DPT resulted in a concentration-dependent decrease in cell viability with median lethal concentration (LC₅₀) of 2.97 μM and 7.24 μM, respectively. However, DMT at concentrations up to 128 μM had no obvious effect on cell viability. The mechanistic study revealed that the extent of apoptosis was greater for DBT than that for DPT, followed by DMT, as evidenced by acridine orange/ethidium bromide (AO/EB) fluorescent staining method and annexin V-FITC/PI staining flow cytometry analysis, as well as generation of intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP) disruption, release of cytochrome c (Cyt c), and consequent activation of caspase-9, and -3. These investigations suggested that the cytotoxic potency of three diorganotins in PC12 cells was in the order of DBT>DPT≫DMT, and these compounds could induce PC12 cells apoptosis through ROS mediated mitochondrial pathway.