Simvastatin attenuates silica-induced pulmonary inflammation and fibrosis in rats via the AMPK-NOX pathway.

BACKGROUND: Simvastatin (Sim), a hydroxy-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, has been widely used in prevention and treatment of cardiovascular diseases. Studies have suggested that Sim exerts anti-fibrotic effects by interfering fibroblast proliferation and collagen synthesis. This study was to determine whether Sim could alleviate silica-induced pulmonary fibrosis and explore the underlying mechanisms. METHODS: The rat model of silicosis was established by the tracheal perfusion method and treated with Sim (5 or 10 mg/kg), AICAR (an AMPK agonist), and apocynin (a NOX inhibitor) for 28 days. Lung tissues were collected for further analyses including pathological histology, inflammatory response, oxidative stress, epithelial mesenchymal transformation (EMT), and the AMPK-NOX pathway. RESULTS: Sim significantly reduced silica-induced pulmonary inflammation and fibrosis at 28 days after administration. Sim could reduce the levels of interleukin (IL)-1ß, IL-6, tumor necrosis factor-α and transforming growth factor-ß1 in lung tissues. The expressions of hydroxyproline, α-SMA and vimentin were down-regulated, while E-cad was increased in Sim-treated rats. In addition, NOX4, p22pox, p40phox, p-p47phox/p47phox expressions and ROS levels were all increased, whereas p-AMPK/AMPK was decreased in silica-induced rats. Sim or AICAR treatment could notably reverse the decrease of AMPK activity and increase of NOX activity induced by silica. Apocynin treatment exhibited similar protective effects to Sim, including down-regulating of oxidative stress and inhibition of the EMT process and inflammatory reactions. CONCLUSIONS: Sim attenuates silica-induced pulmonary inflammation and fibrosis by downregulating EMT and oxidative stress through the AMPK-NOX pathway.

The value of single biomarkers in the diagnosis of silicosis: A meta-analysis.

This study aims to establish a scientific foundation for early detection and diagnosis of silicosis by conducting meta-analysis on the role of single biomarkers in independent diagnosis. The combined sensitivity (Sen), specificity (Spe), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic score, and diagnostic odds ratio (DOR) were 0.84 (95% confidence interval (CI): 0.77-0.90), 0.83 (95% CI: 0.78-0.88), 5.08 (95% CI: 3.92-6.59), 0.19 (95% CI: 0.13-0.27), 3.31 (95% CI: 2.88-3.74) and 27.29 (95% CI: 17.77-41.91), respectively. The area under the curve (AUC) was 0.90 (95% CI: 0.88-0.93). The Fagan plot shows a positive posterior probability of 82% and a negative posterior probability of 15%. This study establishes an academic basis for the swift identification, mitigation, and control of silicosis through scientific approaches. The assessed biomarkers offer precision and dependability in silicosis diagnosis, opening novel paths for early detection and intervention, thereby mitigating the disease burden associated with silicosis.

Methylmercury induces inflammatory response and autophagy in microglia through the activation of NLRP3 inflammasome.

Methylmercury (MeHg) is a global environmental pollutant with neurotoxicity, which can easily crosses the blood-brain barrier and cause irreversible damage to the human central nervous system (CNS). CNS inflammation and autophagy are known to be involved in the pathology of neurodegenerative diseases. Meanwhile, MeHg has the potential to induce microglia-mediated neuroinflammation as well as autophagy. This study aims to further explore the exact molecular mechanism of MeHg neurotoxicity. We conducted in vitro studies using BV2 microglial cell from the central nervous system of mice. The role of inflammation and autophagy in the damage of BV2 cells induced by MeHg was determined by detecting cell viability, cell morphology and structure, reactive oxygen species (ROS), antioxidant function, inflammatory factors, autophagosomes, inflammation and autophagy-related proteins. We further investigated the relationship between the inflammatory response and autophagy induced by MeHg by inhibiting them separately. The results indicated that MeHg could invade cells, change cell structure, activate NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome and autophagosome, release a large amount of inflammatory factors and trigger the inflammatory response and autophagy. It was also found that MeHg could disrupt the antioxidant function of cells. In addition, the inhibition of NLRP3 inflammasome alleviated both cellular inflammation and autophagy, while inhibition of autophagy increased cellular inflammation. Our current research suggests that MeHg might induce BV2 cytotoxicity through inflammatory response and autophagy, which may be mediated by the NLRP3 inflammasome activated by oxidative stress.

Inhibiting ferroptosis in brain microvascular endothelial cells: A potential strategy to mitigate polystyrene nanoplastics‒induced blood‒brain barrier dysfunction.

Polystyrene nanoplastics (PS-NPs), a group of ubiquitous pollutants, may injure the central nervous system through the blood‒brain barrier (BBB). However, whether exposure to PS-NPs contributes to BBB disruption and the underlying mechanisms are still unclear. In vivo, we found that PS-NPs (25 mg/kg BW) could significantly increase BBB permeability in mice and downregulate the distribution of the tight junction-associated protein zona occludens 1 (ZO-1) in brain microvascular endothelial cells (BMECs). Using an in vitro BBB model, exposure to PS-NPs significantly reduced the transendothelial electrical resistance and altered ZO-1 expression and distribution in a dose-dependent manner. RNA-seq analysis and functional investigations were used to investigate the molecular pathways involved in the response to PS-NPs. The results revealed that the ferroptosis and glutathione metabolism signaling pathways were related to the disruption of the BBB model caused by the PS-NPs. PS-NPs treatment promoted ferroptosis in bEnd.3 cells by inducing disordered glutathione metabolism in addition to Fe2+ and lipid peroxide accumulation, while suppressing ferroptosis with ferrostatin-1 (Fer-1) suppressed ferroptosis-related changes in bEnd.3 cells subjected to PS-NPs. Importantly, Fer-1 alleviated the decrease in ZO-1 expression in bEnd.3 cells and the exacerbation of BBB damage induced by PS-NPs. Collectively, our findings suggest that inhibiting ferroptosis in BMECs may serve as a potential therapeutic target against BBB disruption induced by PS-NPs exposure.

Silica nanoparticles induce ferroptosis of HUVECs by triggering NCOA4-mediated ferritinophagy.

Silica nanoparticles (SiNPs) have been widely used in electronics, chemistry, and biomedicine. Human exposure to SiNPs and possible health effects have attracted much attention. The potential cardiovascular toxicity of SiNPs and their related mechanisms are still unclear. Therefore, in this study, we investigated the toxic effects of SiNPs on human umbilical vein endothelial cells (HUVECs). We found that SiNPs could induce HUVECs ferroptosis. The results showed that the level of intracellular divalent iron and lipid peroxidation increased, and mitochondrial cristae decreased. In addition, the pretreatment of the iron chelator deferoxamine mesylate (DFO) could alleviate the ferroptosis of cells. Interestingly, pretreatment of 3-methyladenine (3-MA), an autophagy/PI3K inhibitor could partially inhibit autophagy and reduce ferroptosis, which indicated that autophagy played an important role in cell ferroptosis. Additionally, after knocking down nuclear receptor coactivator 4 (NCOA4), Ferritin Heavy Chain 1 (FTH1) expression was up-regulated, and the levels of divalent iron and lipid peroxidation decreased, which suggested that NCOA4 mediated the ferroptosis of HUVECs induced by SiNPs. In conclusion, this study shows that SiNPs can induce cardiovascular toxicity in which there is ferroptosis. NCOA4-mediated ferritinophagy and resultant ferroptosis by SiNPs may play an important role. This study provides a new theoretical strategy for the treatment and prevention of cardiovascular diseases in the future.

Involvement of the JNK/HO­1/FTH1 signaling pathway in nanoplastic­induced inflammation and ferroptosis of BV2 microglia cells.

Nanoplastics (NPs) are a newly discovered type of environmental pollutant. The potential for neurotoxicity caused by NPs and their mechanisms are unclear. The present study aimed to determine the molecular mechanism underlying neurotoxicity induced by NPs. Microglia (BV2) cells were used for in vitro studies, and it was found that NPs invaded cells, activated inflammasomes, induced the release of significant quantities of inflammatory factors by detection of inflammatory response­associated proteins through Western blot and ELISA. By detection of FITC, SOD, GSH, cellular iron level, and ferroptosis­related proteins, it was found that NPs compromised the anti­oxidative mechanisms of cells, increased intracellular lipid peroxidation and Fe2+ concentration and triggered inflammatory reactions and ferroptosis. Pretreatment with reactive oxygen species (ROS) inhibitor N­acetylcysteine (NAC) alleviated induction of inflammatory reactions and ferroptosis of cells. In addition, inhibiting expression of c­Jun N­terminal kinase (JNK) increased expression of heme oxygenase (HO­1), resulting in decreased ferroptosis, indicating that the JNK/HO­1 signaling pathway was involved in NP­induced effects on ferroptosis in BV2 cells. In conclusion, NPs could induce inflammatory responses and ferroptosis in BV2 cells. JNK/HO­1 mediated ferroptosis may serve an important role in the toxicity of microglia induced by NPs. This study provided novel evidence for the toxic effects of NPs and highlighted a theoretical mechanistic basis for safe prevention and treatment of plastic pollution­induced neurotoxicity.

Efficacy of Alveolar Type II Epithelial Cell Transplantation for Pulmonary Fibrosis: A Meta-Analysis.

Background: Cell transplantation is a promising therapeutic strategy for pulmonary fibrosis. In order to clarify the alveolar type II epithelial cell potential utility in the treatment of lung disease, we conducted a meta-analysis, to evaluate alveolar type II epithelial cells in animal models of lung injury and pulmonary fibrosis. Methods: This review followed the recommendations from the PRISMA statements, Comprehensive retrieval method was used to search Embase, PubMed, Cochrane, Chinese Knowledge Infrastructure, VIP and Wanfang databases. A total of 7 studies and 286 model rats were included. Two researchers independently screened the identified studies, based on inclusion and exclusion criteria. All analyses were conducted using Review Manager V.5.3 software. The combined standard mean difference (SMD) and 95% confidence interval (CI) of data from the included studies were calculated using fixed or random-effects models. Results: The analysis of three outcome indexes showed that the heterogeneity of the oxygen saturation group was high (I2=85%), the lung weight group (I2=64%) was close to moderate heterogeneity, and the lung hydroxyproline content group (I2=0) was not heterogeneous. Conclusion: Meta-analysis showed that transplantation of alveolar type II epithelial cells has beneficial effects, and no obvious adverse reactions. Alveolar type II epithelial cell transplantation can significantly reduce the intervention group and lung hydroxyproline content weight, improve the blood oxygen saturation, lung histo-pathology showed significant improvement in pulmonary fibrosis.

Silica Nanoparticles Cause Activation of NLRP3 Inflammasome in-vitro Model-Using Microglia.

Introduction: Silica nanoparticles (SiNPs) have been widely used in food, cosmetics, medicine and other fields; however, there have been growing concerns regarding their potential adverse effects on health. A large number of studies have confirmed that SiNPs with small particle diameters can pass through the blood brain barrier, causing irreversible damage to the nervous system. This study aims to further explore the molecular mechanism of neurotoxicity of SiNPs and provide a toxicological basis for the medical application of SiNPs. Methods: We conducted an in vitro study using neuroimmune cells (mouse microglial cells, BV2) of the central nervous system to study inflammation and ferroptosis after exposure to SiNPs. We detected cell viability, morphology and ultrastructure, antioxidant function, inflammation, and ferroptosis-related proteins to explore the role of pyroptosis and ferroptosis in the damage of BV2 cells induced by SiNPs. We further explored the relationship between the inflammatory response and ferroptosis induced by SiNPs by silencing the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) gene and inhibiting ferroptosis. Results: The results showed that SiNPs could invade the cytoplasm, change the ultrastructure, activate NLRP3 inflammasomes, release a large number of inflammatory factors, and trigger inflammatory reaction. We also found that SiNPs could disrupt cellular antioxidant function, increase intracellular ferrous ion level and induce ferroptosis. In addition, both inflammation and ferroptosis are alleviated in NLRP3 gene-silenced cells. Conclusion: SiNPs could induce BV2 cytotoxicity through inflammatory response and ferroptosis, which may be mediated by the activation of the NLRP3 inflammasomes.

Methylmercury induced apoptosis of human neuroblastoma cells through the reactive oxygen species mediated caspase and poly ADP-ribose polymerase/apoptosis-inducing factor dependent pathways.

Methylmercury (MeHg) is an environmental neurotoxic substance, which can easily cross the blood-brain barrier, causing irreversible damage to the human central nervous system. Reactive oxygen species (ROS) are involved in various ways of intracellular physiological or pathological processes including neuronal apoptosis. This study attempted to explore the role of ROS-mediated poly ADP-ribose polymerase (PARP)/apoptosis-inducing factor (AIF) apoptosis signaling pathway in the process of MeHg-induced cell death of human neuroblastoma cells (SH-SY5Y). Here, we found that SH-SY5Y cells underwent apoptosis in response to MeHg, which was accompanied by the increased levels of ROS and calcium ion, and the activation of caspase cascades and PARP. Inhibiting the production of ROS can reduce the apoptosis rate to a certain extent. PARP/AIF apoptotic pathway is independent of caspase dependent signaling pathway and regulates it. In conclusion, these results suggest that ROS mediated activation of caspase pathway and PARP/AIF signaling pathway are involved in MeHg induced apoptosis, and these two pathways interact with each other.

Integrative transcriptomic and proteomic analysis reveals mechanisms of silica-induced pulmonary fibrosis in rats.

BACKGROUND: Silicosis is a systemic disease characterized by persistent inflammation and incurable pulmonary fibrosis. Although great effort has been made to understand the pathogenesis of the disease, molecular mechanism underlying silicosis is not fully elucidated. This study was aimed to explore proteomic and transcriptomic changes in rat model of silicosis. METHODS: Twenty male Wistar rats were randomly divided into two groups with 10 rats in each group. Rats in the model group were intratracheally instilled with 50 mg/mL silicon dioxide (1 mL per rat) and rats in the control group were treated with 1.0 mL saline (1 mL per rat). Twenty-eight days later, transcriptomic analysis by microarray and tandem mass tags (TMT)-based proteomic analysis were performed to reveal the expression of mRNAs and proteins in lung tissues. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were applied to analyze the altered genes and proteins. The integrated analysis was performed between transcriptome and proteome. The data were further verified by RT-qPCR and parallel reaction monitoring (PRM). RESULTS: In total, 1769 differentially expressed genes (DEGs) and 650 differentially expressed proteins (DEPs) were identified between the silicosis model and control groups. The integrated analysis showed 250 DEPs were correlated to the corresponding DEGs (cor-DEPs-DEGs), which were mainly enriched in phagosome, leukocyte transendothelial migration, complement and coagulation cascades and cellular adhesion molecule (CAM). These pathways are interrelated and converged at common points to produce an effect. GM2a, CHI3L1, LCN2 and GNAI1 are involved in the extracellular matrix (ECM) and inflammation contributing to fibrosis. CONCLUSION: Our comprehensive transcriptome and proteome data provide new insights into the mechanisms of silicosis and helpful information for more targeted prevention and treatment of silicosis.

Microcrystalline silica particles induce inflammatory response via pyroptosis in primary human respiratory epithelial cells.

The mechanism of the sterile inflammatory response in the respiratory tract induced by exposure to sterile particles has not been fully elucidated. The aim of our study is to explore the earlier events in initiating inflammatory response at molecular and cellular level in primary cultured human airway epithelial cells (AEC) exposed to silica particles in order to provide information for earlier diagnosis and prevention of silica particle-induced toxicity as well as possible information on the genesis of silicosis. We isolated primary AEC from three healthy adults and treated them with silica particles at different concentrations for 48 h. We found evidence for silica-induced inflammasome activation by the co-localization of Caspase-1 and NLRP3, as well as increased levels of IL-1ß and IL-18. Lactate dehydrogenase and NucGreen analysis proved the occurrence of pyroptosis. High throughput mRNA sequencing showed that the inflammatory response and NF-κB signaling pathways were significantly enriched in gene ontology and Kyoto encyclopedia of genes and genomes analysis, and pyroptosis-related genes were up-regulated. The miR-455-3p and five lncRNAs (LOC105375913, NEAT1, LOC105375181, LOC100506098, and LOC105369370) were verified as key factors related to the mechanism by ceRNA network analysis. LOC105375913 was first discovered to be associated with inflammation in AEC. These data suggest that microcrystalline silica can induce significant inflammation and pyroptosis in human primary AEC through NLRP3 inflammasome pathway and NF-κB signaling pathway at both the gene and protein levels, and the possible mechanism could be miR-455-3p mediated ceRNA hypothesis. Our data provide a method for the studies of the respiratory toxicity of fine particulate matter and the pathogenesis of early silicosis. The miR-455-3p and five lncRNAs related ceRNA network might be the toxicity mechanism of microcrystalline silica particles to AEC.

Activation of pyroptosis and ferroptosis is involved in the hepatotoxicity induced by polystyrene microplastics in mice.

Microplastics (MPs) are new environmental pollutants and have received widespread attention in recent years, but the toxicity of the MPs remains to be fully elucidated. To explore the effect of MPs on hepatotoxicity in mice and unravel the mechanism of pyroptosis and ferroptosis in the process of liver injury, we treated mice with 5.0 µm polypropylene microplastics (MPs) at 0.1, 0.5 and 1 mg/mL for 4 weeks. Results revealed that MPs could damage liver structure and function with broken and reduced mitochondrial cristae, as well as increased levels of aspartate minotransferase (AST), alanine aminotransferase (ALT), AST/ALT, alkaline phosphatase (ALP) and lactate dehydrogenase (LDH). Treatment with MPs resulted in pyroptosis as evidenced by increasing expressions of interleukin IL-1ß, IL-18. Additionally, MPs were shown to induce the NOD-like receptor protein 3 (NLRP3) inflammasomes and apoptosis associated speck-like protein (ASC) containing a caspase recruitment domain activation in liver tissue, enabling activation of Caspase-1-dependent signaling pathway induced by inflammatory stimuli resulting from oxidative stress. In addition, the increase of malondialdehyde (MDA) and decrease of glutathione (GSH) and superoxide dismutase (SOD) in the liver indicated that MPs could induce oxidative damage. Moreover, MPs induced lipid peroxidation in the liver of mice could activate the expression of ferroptosis related proteins, including iron metabolism, such as transferrin receptor (TFRC) was active but ferritin heavy chain 1 (FTH1) was inhibited; amino acid metabolism, such as XCT system and glutathione peroxidase 4 (GPX4) were inhibited; lipid metabolism, such as acyl-CoA synthetase long-chain family member 4 (ACSL4) was inhibited. Collectively, these findings evidenced that pyroptosis and ferroptosis occurred in MPs-induced liver injury accompanied by intense oxidative stress and inflammation.

Exosomes derived from bone marrow mesenchymal stem cells reverse epithelial-mesenchymal transition potentially via attenuating Wnt/ß-catenin signaling to alleviate silica-induced pulmonary fibrosis.

Pulmonary fibrosis induced by silica dust is an irreversible, chronic, and fibroproliferative lung disease with no effective treatment at present. BMSCs-derived exosomes (BMSCs-Exo) possess similar functions to their parent cells. In this study, we investigated the therapeutic potential and underlying molecular mechanism for BMSCs-Exo in the treatment of silica-induced pulmonary fibrosis. The rat model of experimental silicosis pulmonary fibrosis was induced with 1.0 mL of one-off infusing silica suspension using the non-exposed intratracheal instillation (50 mg/mL/rat). In vivo transplantation of BMSCs-Exo effectively alleviated silica-induced pulmonary fibrosis, including a reduction in collagen accumulation, inhibition of TGF-ß1, and decreased HYP content. Treatment of BMSCs-Exo increased the expression of epithelial marker proteins including E-cadherin (E-cad) and cytokeratin19 (CK19) and reduced the expression of fibrosis marker proteins including α-Smooth muscle actin (α-SMA) after exposure to silica suspension. Furthermore, we found that BMSCs-Exo inhibited the expression of Wnt/ß-catenin pathway components (P-GSK3ß, ß-catenin, Cyclin D1) in pulmonary fibrosis tissue. BMSCs-Exo is involved in the alleviation of silica-induced pulmonary fibrosis by reducing the level of profibrotic factor TGF-ß1 and inhibiting the progression of epithelial-mesenchymal transition (EMT). Additionally, attenuation of the Wnt/ß-catenin signaling pathway closely related to EMT may be one of the mechanisms involved in anti-fibrotic effects of exosomes.

Activation of Nrf2/HO-1 signaling pathway attenuates ROS-mediated autophagy induced by silica nanoparticles in H9c2 cells.

Silica nanoparticles (SiNPs) as one of the most productive nano-powder, has been extensively applied in various fields. There has been increasing concern about the adverse effects of SiNPs on the health of ecological organisms and human. The potential cardiovascular toxicity of SiNPs and involved mechanisms remain elusive. Hence, in this study, we investigated the cardiovascular toxicity of SiNPs (60 nm) and explored the underlying mechanisms using H9c2 cardiomyocytes. Results showed that SiNPs induced oxidative stress and activated the Nrf2/HO-1 antioxidant pathway. Autophagy was also activated by SiNPs. Interestingly, N-acetyl-L-cysteine (NAC）attenuated autophagy after inhibiting reactive oxygen species (ROS). Meanwhile, down-regulation of Nrf2 enhanced autophagy. In summary, these data indicated that SiNPs induce autophagy in H9c2 cardiomyocytes through oxidative stress, and the Nrf2/HO-1 pathway has a negative regulatory effect on autophagy. This study provides new evidence for the cardiovascular toxicity of SiNPs and provides a reference for the safe use of nanomaterials in the future.

High-fat diet exacerbates lead-induced blood-brain barrier disruption by disrupting tight junction integrity.

Environmental exposure to lead (Pb) can damage to the central nervous system (CNS) in humans. High-fat diet (HFD) also has been suggested to impair neurocognitive function. Blood-brain barrier (BBB) is a rigorous permeability barrier for maintaining homeostasis of CNS. The damage of BBB caused by tight junctions (TJs) disruption is central to the etiology of various CNS disorders. This study aimed to investigate whether HFD could exacerbate Pb exposure induced the destruction of BBB integrity by TJs disruption. To this end, we measured cell viability assay, trans-endothelial electrical resistance assay, horseradish peroxidase flux measurement, Western blot analysis, and immunofluorescence experiments. The results showed that palmitic acid (PA), the most common saturated fatty acid found in the human body, can increase the permeability of the BBB in vitro which formed in bEnd.3 cells induced by Pb exposure, and decrease the expression of TJs, such as zonula occludins-1 (ZO-1) and occludin. Besides, we found that PA could promote the up-regulation of matrix metalloproteinase (MMP)-9 expression and activate the c-Jun N-terminal kinase (JNK) pathway induced by Pb. MMP-9 inhibitor or JNK inhibitor could increase BBB integrity and up-regulate the expressions of ZO-1 and occludin after treatment, respectively. Moreover, the JNK inhibitor could down-regulate the expression of MMP-9. In conclusion, these results suggested that HFD exacerbates Pb-induced BBB disruption by disrupting TJs integrity. This may be because PA promotes the activation of JNK pathway and then up-regulated the expression of MMP-9 after Pb-exposure. It is suggested that people with HFD exposed to environmental Pb may cause more serious damage to the CNS.

Understanding the mechanisms of silica nanoparticles for nanomedicine.

As a consequence of recent progression in biomedicine and nanotechnology, nanomedicine has emerged rapidly as a new discipline with extensive application of nanomaterials in biology, medicine, and pharmacology. Among the various nanomaterials, silica nanoparticles (SNPs) are particularly promising in nanomedicine applications due to their large specific surface area, adjustable pore size, facile surface modification, and excellent biocompatibility. This paper reviews the synthesis of SNPs and their recent usage in drug delivery, biomedical imaging, photodynamic and photothermal therapy, and other applications. In addition, the possible adverse effects of SNPs in nanomedicine applications are reviewed from reported in vitro and in vivo studies. Finally, the potential opportunities and challenges for the future use of SNPs are discussed. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Lead-induced cardiomyocytes apoptosis by inhibiting gap junction intercellular communication via autophagy activation.

Lead (Pb) is one of the most common heavy metal contaminants in the environment. Pb can cause pathophysiological changes in several organ systems, including the cardiovascular system, but the molecular mechanism remains elusive. The study aimed to study the effects of Pb on Gap junction intercellular communication (GJIC) and its role in Pb-induced apoptosis. The present study aims to determine whether Pb-induced autophagy promotes apoptosis of rat cardiac myocytes (H9c2 cells) by downregulating GJIC using CCK-8 Kit, scrape loading/dye transfer assay, Annexin V/PI assays, Western blot analysis and double-immunofluorescence experiments. The results showed that Pb elicited cytotoxicity in a time- and concentration-dependent manner and led to increased apoptosis in a concentration-dependent manner in H9c2 cells. Pb also reduced GJIC in H9c2 cells in a concentration-dependent manner through the downregulation of connexin (Cx) 43. Inhibition of gap junctions by gap junction blocker carbenoxolone disodium (CBX) resulted in increased apoptosis. Furthermore, Pb increased autophagy in a concentration-dependent manner in H9c2 cells, decreasing the distribution of Cx43 on the cell membrane, and targeted Cx43 to autophagosome via light chain 3 (LC3). However, autophagy inhibitor 3-Methyladenine (3-MA) can slow down the downregulation of Cx43 induced by Pb in H9c2 cells. In conclusion, our results provide evidence that Pb-decreased GJIC promotes apoptosis in cardiomyocytes. This is probably because of the fact that Pb-induced autophagy exacerbates GJIC inhibition and downregulation of Cx43.

Silica nanoparticles induce mitochondrial pathway-dependent apoptosis by activating unfolded protein response in human neuroblastoma cells.

The application of silica nanoparticles (SiNPs) in areas of agriculture and medicine has raised great concerns for the potential adverse effects of SiNPs. The increasing toxicological studies focused mainly on the lung and cardiovascular system, but the adverse effects of SiNPs on nervous system have not been well explored. This study aimed to evaluate the role and mechanism of unfolded protein reaction (UPR) in SiNPs-induced cell injury on nerve cells in vitro. We investigated the UPR-mediated apoptosis caused by SiNPs in human neuroblastoma (SH-SY5Y) cell line. The size of SiNPs and its effect on cell ultrastructure were observed by transmission electron microscopy (TEM). Cell growth, mitochondrial membrane potential (MMP), calcium ion (Ca2+ ), apoptosis rate, and the expression level of related proteins were evaluated using MTT, flow cytometry, and western blot in SH-SY5Y cells exposed to SiNPs. The results showed that with the increase of SiNPs concentration, cell viability decreased, MMP decreased, active oxygen (ROS), and Ca2+ levels increased in a dose-dependent manner. In addition, protein expression of PERK, GRP78, and other related proteins in the unfolded protein response increased in a dose-response manner together with the expression of apoptosis proteins. Conclusively, this study confirmed that SiNPs can affect the neural system by interfering structure and functional and inducing apoptosis in nerve cells through unfolded protein response.

Investigation on risk factors of haemorrhagic fever with renal syndrome (HFRS) in Xuancheng City in Anhui Province, Mainland China.

Haemorrhagic fever with renal syndrome (HFRS), a rodent-borne disease, is a major public health concern in both developed and developing countries. China is the most severe endemic country in the world, constituting 90% of the cases. Although the incidence of HFRS has substantively decreased in most areas of China, HFRS has rebounded remarkably in some epidemic areas. Xuancheng is one of these areas. In this study, we collected the case data reported recently in Xuancheng and designed a 1:3 case-control study. The Chi-square test, univariate and multivariate logistic regression analysis were performed. In all cases, farmers made up the highest proportion of occupations. And there were 20 variables with statistical significance including indoor hygienic conditions; the surrounding environment; whether bitten by rats at work and other criteria. In addition, exposure to rodents and rats bites is a high-risk factor for HFRS. Rodent density was calculated at 20.9% (159/760), the virus carrier rate was 9.4% (15/159) and the index of rats with a virus was about 2.0%. Exposure to rodents and insect bites is also high-risk factors for HFRS among local residents in Xuancheng. More importantly, during the flood years, the increased density of rodents led to an increased risk of human exposure to rodents. As our statistical analysis proves, targeted strategies should be developed and implemented to reduce the incidence of local diseases in the future.

Comparative proteomic analysis of silica-induced pulmonary fibrosis in rats based on tandem mass tag (TMT) quantitation technology.

Silicosis is a systemic disease characterized by chronic persistent inflammation and incurable pulmonary fibrosis with the underlying molecular mechanisms to be fully elucidated. In this study, we employed tandem mass tag (TMT) based on quantitative proteomics technology to detect differentially expressed proteins (DEPs) in lung tissues of silica-exposed rats. A total of 285 DEPs (145 upregulated and 140 downregulated) were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to predict the biological pathway and functional classification of the proteins. Results showed that these DEPs were mainly enriched in the phagosome, lysosome function, complement and the coagulation cascade, glutathione metabolism, focal adhesion and ECM-receptor interactions. To validate the proteomics data, we selected and analyzed the expression trends of six proteins including CD14, PSAP, GM2A, COL1A1, ITGA8 and CLDN5 using parallel reaction monitoring (PRM). The consistent result between PRM and TMT indicated the reliability of our proteomic data. These findings will help to reveal the pathogenesis of silicosis and provide potential therapeutic targets. Data are available via ProteomeXchange with identifier PXD020625.