The effects of antimony on Alzheimer's disease-like pathological changes in mice brain

Antimony induces mitochondria-dependent and ER stress-triggered apoptosis via the oxidative stress-activated JNK signaling pathway in pancreatic islet β-cells

Antimony (Sb), a silvery-white metal, is a heavy metal of particular prevalence that has the ability to result in adverse effects in humans through environmental exposure resulting from natural processes and human activities. Epidemiological studies have suggested that Sb has an association with the potential for diabetes mellitus (DM) development. However, the mechanisms by which Sb exerts toxicological effects on pancreatic islet β-cells are still not clear. In this investigation, Sb exposure significantly inhibited rat pancreatic islet β-cell-derived RIN-m5F cell viability and insulin secretion, while inducing mitochondria-dependent apoptotic signals, inclusive of increased apoptotic cell populations, caspase-3 activity, the expression of PARP and caspase-3/-7/-9, and mitochondrial dysfunction. RIN-m5F cells exposure to Sb also led to the triggering of endoplasmic reticulum (ER) stress via the induction of a number of vital molecules, including CHOP, XBP-1s, and caspase-12. In Sb-exposed RIN-m5F cells, 4-PBA pretreatment (an inhibitor of ER stress) significantly suppressed protein expression related to ER stress and events of an apoptotic nature. Furthermore, exposure to Sb resulted in the significant activation of AMPKα, ERK1/2, and JNK signaling, as well as reactive oxygen species (ROS) generation. Pretreatment with SP600125 (an inhibitor of JNK) and antioxidant NAC, but not PD98059 (an inhibitor of ERK) or compound C (an inhibitor of AMPK), effectively abrogated the cytotoxicity, ER stress responses, mitochondrial dysfunction, apoptotic events, insulin secretion inhibition, and JNK activation in Sb-exposed rat pancreatic islet β-cells. However, SP600125 did not prevent ROS generation, which was inhibited by the antioxidant NAC. Collectively, the results demonstrate exposure to Sb to exert β-cell cytotoxicity through oxidative stress-activated JNK signaling downstream-regulated mitochondria-dependent and ER stress-triggered cell apoptotic pathways, eventually resulting in the death of rat pancreatic islet β-cells.

Antimony-induced hippocampal neuronal impairment through ferroptosis activation from NCOA4-mediated ferritinophagy

Recently, our group identified antimony (Sb) as a novel nerve pollutant, can lead to neuronal injure. However, Sb-associated neurotoxicological mechanisms yet remain unclear. Herein, we found Sb induced hippocampal neuronal ferroptosis in vivo and in vitro. Moreover, ferroptosis inhibition using ferrostatin-1 effectively attenuated Sb-induced neuronal damage in PC12 cells and mice hippocampal regions. Furthermore, iron chelator deferoxamine (DFO) also effectively attenuated ferroptosis and cytotoxicity in PC12 cells. In vitro, Sb treatment reduced expression of the heavy (H)- and light (L)-chain subunits of ferritin (FTH1 and FTL). Moreover, Sb accelerated FTH1 and FTL protein degradation, while ferritin overexpression by plasmid or hippocampal AAV injections dramatically weaken Sb-induced ferroptosis. Sb exposure accelerated autophagic flux, and autophagy inhibition with beclin1 knockdown effectively reduced Sb-mediated ferroptosis. 3-methyladenine treatment in Sb-exposed mice prevented the decrease of FTH1 and FTL protein, resulting in recovery of Sb-induced hippocampal ferroptosis as well as neuronal loss, suggesting that Sb triggered hippocampal neuronal ferritinophagy. Finally, we found Sb upregulated NCOA4 protein expression, while NCOA4 knockdown significantly attenuated Sb-triggered ferroptosis. Collectively, our results proved that Sb triggers hippocampal neuronal ferroptosis through NCOA4-dependent ferritinophagy.

Nano-mediated Management of Metal Toxicity-induced Neurodegeneration: A Critical Review

Heavy metals, omnipresent in the environment, though imperative in trace quantities for human physiology, become a serious health hazard due to their toxicity. Copper, arsenic, lead, iron, and mercury are some examples of the heavy metals responsible for oxidative stress, which is one of the primary factors behind neurodegenerative diseases like Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis. Neurodegeneration is caused by toxicity due to environmental exposure to these toxic substances or genetic variation. Conventional therapies, relying on chelation and antioxidants, suffer from the broader perspective of metal removal in a non-selective manner and poor targeting of the brain. In this respect, treatments based on nanotechnology that employ nanoparticles such as dendrimers, micelles, and liposomes constitute a promising interest in enhancing drug delivery with minimal neurotoxicity. The present review outlines the heavy metals responsible for neurodegenerative diseases, their pathophysiology, management strategies available at present, and the scope of nanotechnology intervention in overcoming shortcomings of conventional therapies. The genetic influence of heavy metals on neurological health is also part of this article.

Exposure to nano-polystyrene during pregnancy leads to Alzheimer's disease-related pathological changes in adult offspring

Nanoplastics are common environmental pollutants. As of now, research has yet to explore how exposure to nanomaterials during gestation might influence the risk of developing Alzheimer's disease (AD) in offspring. Throughout the research, we assessed the AD pathology in adult offspring of mice prenatal 80 nm polystyrene nanoparticles (PS-NPs) exposure. In contrast with the control group, prenatal PS-NPs exposure obviously decreased brain tissue weight and the organ coefficient (brain weight/body weight) in adult male mice, but it only led to changes in the low-dose group of female mice. Histological examination of the adult offspring brains revealed alterations following exposure to PS-NPs during gestation. Specifically, there was a substantial reduction in neuron cells, significant changes in the number of Nissl bodies, noticeable loss of cell nucleus, and increased presence of neurofibrillary tangles in adult offspring mice exposed to PS-NPs during gestation. Furthermore, the phosphorylation levels of tau proteins at ser396 and ser199 were dramatically enhanced in the PS-NPs exposed group. Furthermore, the expression of Aβ protein was markedly increased, consistent with typical AD pathological features. Our findings suggest that being exposed to PS-NPs during pregnancy substantially raises the risk of AD in offspring.

[Research progress on metal pollutants inducing neurotoxicity through ferroptosis]

It has been confirmed that exposure to various metal pollutants can induce neurotoxicity, which is closely associated with the occurrence and development of neurological disorders. Ferroptosis is a form of cell death in response to metal pollutant exposure and it is closely related to oxidative stress, iron metabolism and lipid peroxidation. Recent studies have revealed that ferroptosis plays a significant role in the neurotoxicity induced by metals such as lead, cadmium, manganese, nickel, and antimony. Lead exposure triggers ferroptosis through oxidative stress, iron metabolism disorder and inflammation. Cadmium can induce ferroptosis through iron metabolism, oxidative stress and ferroptosis related signaling pathways. Manganese can promote ferroptosis through mitochondrial dysfunction, iron metabolism disorder and oxidative stress. Nickel can promote ferroptosis by influencing mitochondrial function, disrupting iron homeostasis and facilitating lipid peroxidation in the central nervous system. Antimony exposure can induce glutathione depletion by activating iron autophagy, resulting in excessive intracellular iron deposition and ultimately causing ferroptosis. This article reviews the effects of metal pollutants on ferroptosis-related indicators and discusses the specific mechanisms by which each metal triggers ferroptosis. It provides a reference for identifying targets for preventing neurotoxicity and for developing treatment strategies for neurological disorders.

Insights into the biogeochemical transformation, environmental impacts and biochar-based soil decontamination of antimony

Every year, a significant amount of antimony (Sb) enters the environment from natural and anthropogenic sources like mining, smelting, industrial operations, ore processing, vehicle emissions, shooting activities, and coal power plants. Humans, plants, animals, and aquatic life are heavily exposed to hazardous Sb or antimonide by either direct consumption or indirect exposure to Sb in the environment. This review summarizes the current knowledge about Sb global occurrence, its fate, distribution, speciation, associated health hazards, and advanced biochar composites studies used for the remediation of soil contaminated with Sb to lessen Sb bioavailability and toxicity in soil. Anionic metal(loid) like Sb in the soil is significantly immobilized by pristine biochar and its composites, reducing their bioavailability. However, a comprehensive review of the impacts of biochar-based composites on soil Sb remediation is needed. Therefore, the current review focuses on (1) the fundamental aspects of Sb global occurrence, global soil Sb contamination, its transformation in soil, and associated health hazards, (2) the role of different biochar-based composites in the immobilization of Sb from soil to increase biochar applicability toward Sb decontamination. The review aids in developing advanced, efficient, and effective engineered biochar composites for Sb remediation by evaluating novel materials and techniques and through sustainable management of Sb-contaminated soil, ultimately reducing its environmental and health risks.

Association of four metalloids in the serum and urine of individuals with major depressive disorders: a case-control study

Background

Major depressive disorder (MDD) pathogenesis may involve metalloids in a significant way. The aim of our study was to identify potential links between MDD and metalloid elements [boron (B), germanium (Ge), arsenic (As), antimony (Sb)].

Methods

A total of 72 MDD cases and 75 healthy controls (HCs) were recruited from Zhumadian Second People's Hospital in Henan Province, China. The levels of four metallic elements (B, Ge, As, and Sb) in the serum and urine were measured using inductively coupled plasma mass spectrometry (ICP-MS).

Results

In comparison to the HCs, the B, As, and Sb levels were considerably lower in the MDD group (p < 0.05) in the serum; the MDD group had significantly higher (p < 0.05) and significantly lower (p < 0.001) B and Sb levels in the urine. After adjusting for potential confounders, serum B (OR = 0.120; 95% CI, 0.048, 0.300; p < 0.001) and Sb (OR = 0.133; 95% CI, 0.055, 0.322; p < 0.001) showed a negative correlation with MDD. Urine B had a negative correlation (OR = 0.393; 95% CI, 0.193, 0.801; p = 0.01) with MDD, while urine Sb had a positive correlation (OR = 3.335; 95% CI, 1.654, 6.726; p = 0.001) with MDD.

Conclusion

Our current research offers insightful hints for future investigation into the function of metalloids in connection to MDD processes.

A Prospective Cohort Study of Antimony Exposure and Cognitive Impairment in Older Adults - China, 2017-2021

What is already known about this topic?

Antimony (Sb) has been identified as a new neurotoxicant that impacts neurological functions in animal studies. However, its effects on the human population remain unknown.

What is added by this report?

The study reveals that there is an association between exposure to Sb and a higher incidence of cognitive impairment in older adults. The dose-response curve demonstrates that the risk of cognitive impairment consistently increased with higher levels of Sb exposure without a discernible threshold.

What are the implications for public health practice?

Reducing exposure to Sb may have a beneficial effect in delaying or preventing the onset of cognitive impairment. This intervention has the potential to significantly decrease the disease burden associated with cognitive impairment, ultimately contributing to social development.

Single-cell RNA sequencing analysis to evaluate antimony exposure effects on cell-lineage communications within the Drosophila testicular niche

The increasing production and prevalence of antimony (Sb)-related products raise concerns regarding its potential hazards to reproductive health. Upon environmental exposure, Sb reportedly induces testicular toxicity during spermatogenesis; moreover, it is known to affect various testicular cell populations, particularly germline stem cell populations. However, the cell-cell communication resulting from Sb exposure within the testicular niche remains poorly understood. To address this gap, herein we analyzed testicular single-cell RNA sequencing data from Sb-exposed Drosophila. Our findings revealed that the epidermal growth factor receptor (EGFR) and WNT signaling pathways were associated with the stem cell niche in Drosophila testes, which may disrupt the homeostasis of the testicular niche in Drosophila. Furthermore, we identified several ligand-receptor pairs, facilitating the elucidation of intercellular crosstalk involved in Sb-mediated reproductive toxicology. We employed scRNA-seq analysis and conducted functional verification to investigate the expression patterns of core downstream factors associated with EGFR and WNT signatures in the testes under the influence of Sb exposure. Altogether, our results shed light on the potential mechanisms of Sb exposure-mediated testicular cell-lineage communications.

A Drosophila model of gestational antimony exposure uncovers growth and developmental disorders caused by disrupting oxidative stress homeostasis

The toxic heavy metal antimony (Sb) is ubiquitous in our daily lives. Various models have shown that Sb induces neuronal and reproductive toxicity. However, little is known about the developmental toxicity of Sb exposure during gestation and the underlying mechanisms. To study its effects on growth and development, Drosophila stages from eggs to pupae were exposed to different Sb concentrations (0, 0.3, 0.6 and 1.2 mg/mL Sb); RNA sequencing was used to identify the underlying mechanism. The model revealed that prenatal Sb exposure significantly reduced larval body size and weight, the pupation and eclosion rates, and the number of flies at all stages. With 1.2 mg/mL Sb exposure in 3rd instar larvae, 484 genes were upregulated and 694 downregulated compared to controls. Biological analysis showed that the disrupted transcripts were related to the oxidative stress pathway, as verified by reactive oxygen species (ROS) scavenger N-acetylcysteine (NAC) and glutathione (GSH) intervention experiments. Sb exposure induced oxidative stress imbalance could be rectified by chelation and antioxidant effects of NAC/GSH. The Drosophila Schneider 2 (S2) model further demonstrated that NAC and GSH greatly ameliorated cell death induced by Sb exposure. In conclusion, gestational Sb exposure disrupted oxidative stress homeostasis, thereby impairing growth and development.

Mechanisms of genotoxicity and proteotoxicity induced by the metalloids arsenic and antimony

Arsenic and antimony are metalloids with profound effects on biological systems and human health. Both elements are toxic to cells and organisms, and exposure is associated with several pathological conditions including cancer and neurodegenerative disorders. At the same time, arsenic- and antimony-containing compounds are used in the treatment of multiple diseases. Although these metalloids can both cause and cure disease, their modes of molecular action are incompletely understood. The past decades have seen major advances in our understanding of arsenic and antimony toxicity, emphasizing genotoxicity and proteotoxicity as key contributors to pathogenesis. In this review, we highlight mechanisms by which arsenic and antimony cause toxicity, focusing on their genotoxic and proteotoxic effects. The mechanisms used by cells to maintain proteostasis during metalloid exposure are also described. Furthermore, we address how metalloid-induced proteotoxicity may promote neurodegenerative disease and how genotoxicity and proteotoxicity may be interrelated and together contribute to proteinopathies. A deeper understanding of cellular toxicity and response mechanisms and their links to pathogenesis may promote the development of strategies for both disease prevention and treatment.

Single-cell RNA sequencing reveals cell landscape following antimony exposure during spermatogenesis in Drosophila testes

Antimony (Sb), is thought to induce testicular toxicity, although this remains controversial. This study investigated the effects of Sb exposure during spermatogenesis in the Drosophila testis and the underlying transcriptional regulatory mechanism at single-cell resolution. Firstly, we found that flies exposed to Sb for 10 days led to dose-dependent reproductive toxicity during spermatogenesis. Protein expression and RNA levels were measured by immunofluorescence and quantitative real-time PCR (qRT-PCR). Single-cell RNA sequencing (scRNA-seq) was performed to characterize testicular cell composition and identify the transcriptional regulatory network after Sb exposure in Drosophila testes. scRNA-seq analysis revealed that Sb exposure influenced various testicular cell populations, especially in GSCs_to_Early_Spermatogonia and Spermatids clusters. Importantly, carbon metabolism was involved in GSCs/early spermatogonia maintenance and positively related with SCP-Containing Proteins, S-LAPs, and Mst84D signatures. Moreover, Seminal Fluid Proteins, Mst57D, and Serpin signatures were highly positively correlated with spermatid maturation. Pseudotime trajectory analysis revealed three novel states for the complexity of germ cell differentiation, and many novel genes (e.g., Dup98B) were found to be expressed in state-biased manners during spermatogenesis. Collectively, this study indicates that Sb exposure negatively impacts GSC maintenance and spermatid elongation, damaging spermatogenesis homeostasis via multiple signatures in Drosophila testes and therefore supporting Sb-mediated testicular toxicity.

Association of urinary heavy metals co-exposure and adult depression: Modification of physical activity

OBJECTIVE

This study aimed to evaluate the association between urinary heavy metal mixture exposure and depression, and the modifying role of physical activity in the effects of heavy metal mixture on depression risk was also considered.

METHODS

Data of this study were derived from the National Health and Nutrition Examination Survey 2011-2016. Depression was measured by the Patient Health Questionnaire. We first selected 6 (cadmium, cobalt, tin, antimony, thallium, and mercury) from 14 heavy metals through elastic net regression for further analysis. Then binomial logistic regression, generalized additive model, environment risk score (ERS), and weighted quantile sum (WQS) regression were adopted to assess the effects of six metals individual and cumulative exposure on depression risk. Finally, we also examined whether physical activity could mitigate the effects of heavy metal co-exposure on depression risk.

RESULTS

Totally, 4212 participants were included and 7.40% of subjects were with depression. We found urinary tin and antimony were separately associated with increased odds of depression (Sb: OR = 1.285, 95% CI: 1.064-1.553; Sn: OR = 1.281, 95% CI: 1.097-1.495), and a linear dose-response relationship between tin and depression was also noticed (P < 0.05). Meanwhile, urinary heavy metals co-exposure was positively related to depression risk (ERS_Q4: OR = 2.691, 95% CI: 1.399-5.174; WQS_positive: OR = 1.465, 95% CI: 1.063-2.021), in which tin, antimony, and cadmium were identified with greater contributions to the overall mixture effect. In both ERS and WQS models, the significant positive association between the metal mixture and depression risk remained only in those who were inactive in physical activity.

CONCLUSION

Our study concluded the detrimental effect of heavy metals in combined exposure on the risk of depression, which might be attenuated by physical activity.

Resection of Scar Tissue in Rats With Spinal Cord Injury Can Promote the Expression of βⅢ-tubulin in the Injured Area

BACKGROUND

Previous research shows that scar tissue formed in the injured area after spinal cord injury blocks nerve regeneration and functional recovery. However, those researchers tried to prevent the formation of scar after spinal cord injury to promote nerve regeneration, but it ran counter to their desire, indicating that the formation of scar might play a role in functional recovery after spinal cord injury.

METHODS

To investigate roles of scar formation on functional repair after spinal cord injury, we selected several different key time points to resect the scar tissue formed after spinal cord injury based on the rat models of the T8-T9 transection injury of spinal cord. First, the recovery of motor function was evaluated by Basso Beattie Bresnahan score and electrophysiologic examination; second, the pathologic features of functional recovery were analyzed mainly by immunofluorescence βⅢ-tubulin staining; finally, the genes related to the recovery of motor function were predicted by high-throughput sequencing analysis.

RESULTS

Immunofluorescence results showed that the resection of scar tissue promoted significantly the recovery of motor function and the expression of βⅢ-tubulin in the injured area in the second week after spinal cord injury. Furthermore, RNA-seq studies showed that Tubb3 and Tubb6 gene expression and other neural regeneration pathways were significantly different in the tissue before and after early resection.

CONCLUSIONS

Excision of scar tissue in the second week promoted nerve regeneration after spinal cord injury. Tubb3 and Tubb6 genes might be the potential targets for spinal cord injury therapy in our study.

Level-specific associations of urinary antimony with cognitive function in US older adults from the National Health and Nutrition Examination Survey 2011-2014

BACKGROUND

We have looked at antimony (Sb) as a new neurotoxin which causes neuronal apoptosis in animal studies. At the population level, however, there is no direct evidence for a relationship between Sb exposure and cognitive performance.

METHOD

The study comprehensively assessed the correlation between urinary antimony levels and cognitive test scores in 631 creatinine-corrected older persons using data from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2014.

RESULTS

Using logistic regression, the study looked at the prevalence of cognitive impairment at different levels of urine antimony concentrations and found that, after controlling for covariates, higher doses of urinary antimony were positively associated with cognitive function compared to controls, odds ratio (ORs) with 95% confidence interval (CI) were 0.409 (0.185-0.906) and 0.402 (0.186-0.871) respectively. Restricted cubic spline curves showed a non-linear and dose-specific correlation between urinary antimony and cognitive performance, with lower doses associated with better cognitive performance, while higher doses may be associated with cognitive impairment.

CONCLUSIONS

Our data provide evidence for a correlation between Sb and cognitive function at the population level, although the specific mechanisms need to be investigated further.

Shen Qi Wan Ameliorates Learning and Memory Impairment Induced by STZ in AD Rats through PI3K/AKT Pathway

Alzheimer’s disease is the most common form of neurodegenerative disease, and increasing evidence shows that insulin signaling has crucial roles in AD initiation and progression. In this study, we explored the effect and underlying mechanism of SQW, a representative formula for tonifying the kidney and promoting yang, on improving the cognitive function in a streptozotocin-induced model of AD rats. We investigated memory impairment in the AD rats by using the Morris water test. HE and Nissl staining were employed to observe the histomorphological changes in the hippocampal. Expression levels of NeuN and proteins related to Tau and apoptosis were measured using immunohistochemistry and Western blotting, respectively. Additionally, we performed RNA sequencing, and the selected hub genes were then validated by qRT-PCR. Furthermore, the protein expression levels of PI3K/AKT pathway-related proteins were detected by Western blot. We found that SQW treatment significantly alleviated learning and memory impairment, pathological damage, and apoptosis in rats, as evidenced by an increased level of NeuN and Bcl-2, and decreased phosphorylation of Tau, Bax, and Caspase-3 protein expression. SQW treatment reversed the expression of insulin resistance-related genes (Nr4a1, Lpar1, Bdnf, Atf2, and Ppp2r2b) and reduced the inhibition of the PI3K/AKT pathway. Our results demonstrate that SQW could contribute to neuroprotection against learning and memory impairment in rats induced by STZ through activation of the PI3K/AKT pathway.

GPX4 degradation via chaperone-mediated autophagy contributes to antimony-triggered neuronal ferroptosis

Exposure to antimony (Sb), recently identified as a nerve pollutant, can result in neuron damage; but, associated-neurotoxicological mechanisms were still not clear. Herein, we assessed the role of ferroptosis in Sb-mediated neurotoxicity and clarified the underlying mechanism. Following Sb exposure, ferroptosis was significantly promoted in vivo and in vitro. Moreover, following use of ferrostatin-1 (fer-1) to inhibit ferroptosis, Sb-induced ferroptosis in PC12 cells was effectively attenuated. Sb accelerated lysosomal transport and subsequent degradation of glutathione peroxidase 4 (GPX4), resulting in ferroptosis. Furthermore, chaperone-mediated autophagy (CMA) was activated following treatment with Sb, while inhibition of CMA by lysosomal associated protein 2 A (LAMP2A) knockdown attenuated Sb-induced GPX4 degradation. Sb treatment also increased expression of the chaperones heat shock cognate protein 70 (HSC70) and heat shock protein 90 (HSP90) and the lysosome receptor LAMP2A, and increased binding of HSP90, HSC70, and LAMP2A with GPX4 was observed, indicating increased formation of the chaperone-GPX4 complex. Finally, GPX4 overexpression significantly protected PC12 cells from activation of Sb-stimulated ferroptosis and subsequent cytotoxicity. Collectively, our results provide a original mechanism by which Sb triggers neurotoxicity, to concluded that Sb stimulates neuronal ferroptosis through CMA-mediated GPX4 degradation.

Relationships between urinary antimony concentrations and depressive symptoms in adults

BACKGROUND

Antimony is widely used in industrial production. The general population may be exposed to long-term low-dose antimony, and there are no studies on antimony and depression symptoms. This study aims to explore the relationships between urinary antimony concentrations and depressive symptoms in adults.

METHODS

We conducted a cross-sectional study using data from U.S. National Health and Nutrition Examination Survey (NHANES) 2007-2016 for urinary antimony (N = 8538). Depressive symptoms were assessed through Patient's Health Questionnaire (PHQ-9). In order to determine the relationships between urinary antimony concentrations and depressive symptoms, binary logistic regression model and restricted cubic spline were used. Dominance analysis was used to explore the relative importance between variables associated with depressive symptoms.

RESULTS

There was a significant positive relationship between urinary antimony concentrations and depressive symptoms in the general population, and OR with 95% CI was 1.72 (1.15, 2.60). This relationship also occurred in participants without disease status, and OR with 95% CI was 2.05 (1.10, 3.82). After stratified gender, the urinary antimony concentrations were positively correlated with depressive symptoms in the highest tertiles of female participants, and OR with 95% CI was 1.74 (1.06, 2.86). After adjusted urinary lead, arsenic, cadmium, and mercury as covariates, the result was still statistically significant, and OR with 95% CI was 1.83 (1.23, 2.72). Restricted cubic spline showed a nonlinear positive relationship between urinary antimony and depressive symptoms. Based on the result of dominance analysis, the relative importance of urinary antimony concentration accounted for 3.58%.

CONCLUSION

This study indicated that urinary antimony was positively related to depressive symptoms, especially in female.

Antimony-induced astrocyte activation via mitogen-activated protein kinase activation-dependent CREB phosphorylation

Recent studies suggest that the chemical element antimony (Sb) is neurotoxic; however, the molecular mechanisms behind Sb-related neuronal damage are currently unknown. In this study, we found that Sb exposure promoted astrocyte proliferation and increased the expression of inducible nitric oxide synthase (iNOS) and glial fibrillary acidic protein (GFAP), two key protein markers of reactive astrogliosis, at both the gene and protein level, suggesting that Sb induced astrocyte activation. Moreover, the p38 mitogen-activated protein kinase (p38 MAPK) and extracellular signal-related kinase (ERK) pathways were activated following Sb exposure. Inhibition of p38 MAPK reduced Sb-induced iNOS and GFAP upregulation, while inhibiting ERK reduced GFAP expression only, in Sb-exposed C6 cells. Sb treatment also induced the phosphorylation of cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB), and the inhibition of CREB caused a reduction in Sb-induced GFAP and iNOS expression. Furthermore, inhibiting both p38 MAPK and ERK effectively alleviated CREB phosphorylation in Sb-exposed C6 cells. Taken together, our results suggest that p38 MAPK and ERK activation mediate Sb-induced astrocyte activation through CREB phosphorylation. These results help to clarify the molecular mechanisms underlying Sb-associated neurotoxicity.

Down-regulated long non-coding RNA RMST ameliorates dopaminergic neuron damage in Parkinson's disease rats via regulation of TLR/NF-κB signaling pathway

OBJECTIVE

Current treatment and prognosis of Parkinson's disease (PD) are not ideal. This study explored the mechanism of long non-coding RNA (lncRNA) rhabdomyosarcoma 2-associated transcript (RMST) in dopaminergic (DA) neuron damage in PD rats.

METHODS

PD rats were modeled and injected with RMST silence or overexpression vectors to figure out its roles in oxidative stress, the apoptosis of DA neurons in brain substantia nigra (SN), and neurobehavioral activities of PD rats. Tyrosine hydroxylase (TH), synaptophysin (SYN), glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule (Iba-1) in SN were detected. RMST and Toll-like receptor (TLR)/nuclear factor kappa B (NF-κB) pathway-related factors were detected.

RESULTS

RMST expression in brain SN of rats, TLR2, TLR4 expression in neurons and NF-κB expression in cell nucleus were increased. Silenced RMST improved the neurobehavioral activities, depressed oxidative stress and neuronal apoptosis, increased TH and SYN expression, and reduced the activation degree of glial cells in SN and the inflammatory response via reducing GFAP and Iba-1. Moreover, reduced RMST reduced TLR2 and TLR4 expression in neurons and NF-κB expression in cell nucleus in PD rats.

CONCLUSION

Inhibited RMST attenuates DA neuron damage in PD rats, which may be implicated with TLR/NF-κB signaling pathway.