iTRAQ-based quantitative proteomic analysis reveals important metabolic pathways for arsenic-induced liver fibrosis in rats

Chronic Exposure to Arsenic and Fluoride Starting at Gestation Alters Liver Mitochondrial Protein Expression and Induces Early Onset of Liver Fibrosis in Male Mouse Offspring

The presence of arsenic (As) and fluoride (F-) in drinking water is of concern due to the enormous number of individuals exposed to this condition worldwide. Studies in cultured cells and animal models have shown that As- or F-induced hepatotoxicity is primarily associated with redox disturbance and altered mitochondrial homeostasis. To explore the hepatotoxic effects of chronic combined exposure to As and F- in drinking water, pregnant CD-1 mice were exposed to 2 mg/L As (sodium arsenite) and/or 25 mg/L F- (sodium fluoride). The male offspring continued the exposure treatment up to 30 (P30) or 90 (P90) postnatal days. GSH levels, cysteine synthesis enzyme activities, and cysteine transporter levels were investigated in liver homogenates, as well as the expression of biomarkers of ferroptosis and mitochondrial biogenesis-related proteins. Serum transaminase levels and Hematoxylin-Eosin and Masson trichrome-stained liver tissue slices were examined. Combined exposure at P30 significantly reduced GSH levels and the mitochondrial transcription factor A (TFAM) expression while increasing lipid peroxidation, free Fe 2+, p53 expression, and serum ALT activity. At P90, the upregulation of cysteine uptake and synthesis was associated with a recovery of GSH levels. Nevertheless, the downregulation of TFAM continued and was now associated with a downstream inhibition of the expression of MT-CO2 and reduced levels of mtDNA and fibrotic liver damage. Our experimental approach using human-relevant doses gives evidence of the increased risk for early liver damage associated with elevated levels of As and F- in the diet during intrauterine and postnatal period.

Proteomic analysis of hepatic fibrosis induced by a high starch diet in largemouth bass (Micropterus salmoides)

Largemouth bass is sensitive to the dietary starch level and excess starch can induce metabolic liver diseases (MLD). Hepatic fibrosis is a typical pathological phenotype of MLD in largemouth bass, but the molecular basis underlying is largely unclear. This study fed fish with a low or high starch diet for 4 weeks. Liver tissues with or without fibrotic symptoms were recognized through histopathological and molecular markers analysis of hepatic fibrosis, following TMT Quantitative proteomics and conducted Parallel Reaction Monitoring (PRM) analyses. 2455 differentially expressed proteins with 1618 up-regulated and 837 down-regulated were identified in this study. In GO terms, up-regulated proteins were correlated with cytoskeleton organization, supramolecular fiber, cytoskeleton protein binding, and actin-binding, while down-regulated proteins were involved in mainly metabolism-related processes, and molecular binding activity. Down-regulated proteins were enriched in 63 KEGG pathways and concentrated in metabolism-related pathways, especially glucose, lipid, and amino acid metabolism. 70 KEGG pathways of up-regulated proteins mainly included immunity and inflammation-related pathways. The expression trends of 11 differentially expressed proteins were consistent with proteome results by PRM analysis. In conclusion, the development of hepatic fibrosis induced by high starch may be related to multi-signaling pathways, metabolism processes, and targets, which provides important data for further study on revealing the molecular mechanism of hepatic fibrosis.

Global Quantitative Proteomics Analysis Reveals the Downstream Signaling Networks of Msx1 and Msx2 in Myoblast Differentiation

The msh homeobox 1 (Msx1) and msh homeobox 2 (Msx2) coordinate in myoblast differentiation and also contribute to muscle defects if altered during development. Deciphering the downstream signaling networks of Msx1 and Msx2 in myoblast differentiation will help us to understand the molecular events that contribute to muscle defects. Here, the proteomics characteristics in Msx1- and Msx2-mediated myoblast differentiation was evaluated  using isobaric tags for the relative and absolute quantification labeling technique (iTRAQ). The downstream regulatory proteins of Msx1- and Msx2-mediated differentiation were identified. Bioinformatics analysis revealed that these proteins were primarily associated with xenobiotic metabolism by cytochrome P450, fatty acid degradation, glycolysis/gluconeogenesis, arginine and proline metabolism, and apoptosis. In addition, our data show Acta1 was probably a core of the downstream regulatory networks of Msx1 and Msx2 in myoblast differentiation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-022-00049-y.

Investigating the Neurotoxic Impacts of Arsenic and the Neuroprotective Effects of Dictyophora Polysaccharide Using SWATH-MS-Based Proteomics

Arsenic (As) is one of the most important toxic elements in the natural environment. Currently, although the assessment of the potential health risks of chronic arsenic poisoning has received great attention, the research on the effects of arsenic on the brain is still limited. It has been reported that dictyophora polysaccharide (DIP), a common bioactive natural compound found in dietary plants, could reduce arsenic toxicity. Following behavioral research, comparative proteomics was performed to explore the molecular mechanism of arsenic toxicity to the hippocampi of SD (Sprague Dawley) rats and the protective effect of DIP. The results showed that exposure to arsenic impaired the spatial learning and memory ability of SD rats, while DIP treatment improved both the arsenic-exposed rats. Proteomic analysis showed that arsenic exposure dysregulated the expression of energy metabolism, apoptosis, synapse, neuron, and mitochondria related proteins in the hippocampi of arsenic-exposed rats. However, DIP treatment reversed or restored the expression levels of these proteins, thereby improving the spatial learning and memory ability of arsenic-exposed rats. This study is the first to use high-throughput proteomics to reveal the mechanism of arsenic neurotoxicity in rats as well as the protective mechanism of DIP against arsenic neurotoxicity.

Protective Effect of Dictyophora Polysaccharides on Sodium Arsenite-Induced Hepatotoxicity: A Proteomics Study

The purpose of this study is to understand the mechanism of sodium arsenite (NaAsO₂)-induced apoptosis of L-02 human hepatic cells, and how Dictyophora polysaccharide (DIP) protects L-02 cells from arsenic-induced apoptosis. The results revealed that DIP pretreatment inhibited NaAsO₂ induced L-02 cells apoptosis by increasing anti-apoptotic Bcl-2 expression and decreasing pro-apoptotic Bax expression. Proteomic analysis showed that arsenic treatment disrupted the expression of metabolism and apoptosis associated proteins, including ribosomal proteins (RPs). After pretreatment with DIP, the expression levels of these proteins were reversed or restored. For the first time, it was observed that the significant decrease of cytoplasmic RPs and the increase of mitochondrial RPs were related to human normal cell apoptosis induced by arsenic. This is also the first report that the protective effect of DIP on cells was related to RPs. The results highlight the relationship between RPs and apoptosis, as well as the relationship between RPs and DIP attenuating arsenic-induced apoptosis.

miR-21-regulated M2 polarization of macrophage is involved in arsenicosis-induced hepatic fibrosis through the activation of hepatic stellate cells

Arsenicosis induced by chronic exposure to arsenic is recognized as one of the main damaging effects on public health. Exposure to arsenic can cause hepatic fibrosis, but the molecular mechanisms by which this occurs are complex and elusive. It is not known if miRNAs are involved in arsenic-induced liver fibrosis. We found that in the livers of mice exposed to arsenite, there were elevated levels of microRNA-21 (miR-21), phosphorylated mammalian target of rapamycin (p-mTOR), and arginase 1 (Arg1); low levels of phosphatase and tensin homolog (PTEN); and more extensive liver fibrosis. For cultured cells, arsenite-induced miR-21, p-mTOR, and Arg1; decreased PTEN; and promoted M2 polarization of macrophages derived from THP-1 monocytes (THP-M), which caused secretion of fibrogenic cytokines, including transforming growth factor-β1. Coculture of arsenite-treated, THP-M with LX-2 cells induced α-SMA and collagen I in the LX-2 cells and resulted in the activation of these cells. Downregulation of miR-21 in THP-M inhibited arsenite-induced M2 polarization and activation of LX-2 cells, but cotransfection with PTEN siRNA or a miR-21 inhibitor reversed this inhibition. Moreover, knockout of miR-21 in mice attenuated liver fibrosis and M2 polarization compared with WT mice exposed to arsenite. Additionally, LN, PCIII, and HA levels were higher in patients with higher hair arsenic levels, and levels of miR-21 were higher than controls and positively correlated with PCIII, LN, and HA levels. Thus, arsenite induces the M2 polarization of macrophages via miR-21 regulation of PTEN, which is involved in the activation of hepatic stellate cells and hepatic fibrosis. The results establish a previously unknown mechanism for arsenicosis-induced fibrosis.

Oxymatrine exerts anti-fibrotic effects in a rat model of hepatic fibrosis by suppressing endoplasmic reticulum stress

OBJECTIVE

This study evaluated the anti-fibrotic effects of oxymatrine and the role of endoplasmic reticulum (ER) stress in hepatic fibrosis (HF) in animal models.

METHODS

The HF rat model was established by exposure to NaAsO2, followed by treatment with oxymatrine. Biomarkers of HF and ER stress were measured. The difference in protein expression between groups was evaluated using isobaric tag for relative and absolute quantification (iTRAQ) analysis. The mechanism by which oxymatrine modulated ER stress to alleviate arsenic-induced HF was evaluated using LX2 hepatic stellate cells in vitro.

RESULTS

The rat model mimicked the pathological and physical phenotypes of HF including ER stress, oxidative stress, impaired liver function, and fibrosis. Treatment with oxymatrine suppressed these responses. Moreover, apoptosis, inflammation, and hepatic stellate cell activation were also inhibited by oxymatrine treatment. The differentially expressed proteins and pathways related to ER stress were identified in the HF and oxymatrine-treated groups via iTRAQ analysis combined with liquid chromatography-mass spectrometry. LX2 cells were activated by NaAsO2 in vitro. Meanwhile, oxymatrine suppressed the activation of LX2 cells by alleviating ER stress and regulating cellular calcium homeostasis.

CONCLUSIONS

Oxymatrine could reverse NaAsO2-induced HF by alleviating ER stress.

G3BP1-linked mRNA partitioning supports selective protein synthesis in response to oxidative stress

Cells limit energy-consuming mRNA translation during stress to maintain metabolic homeostasis. Sequestration of mRNAs by RNA binding proteins (RBPs) into RNA granules reduces their translation, but it remains unclear whether RBPs also function in partitioning of specific transcripts to polysomes (PSs) to guide selective translation and stress adaptation in cancer. To study transcript partitioning under cell stress, we catalogued mRNAs enriched in prostate carcinoma PC-3 cell PSs, as defined by polysome fractionation and RNA sequencing (RNAseq), and compared them to mRNAs complexed with the known SG-nucleator protein, G3BP1, as defined by spatially-restricted enzymatic tagging and RNAseq. By comparing these compartments before and after short-term arsenite-induced oxidative stress, we identified three major categories of transcripts, namely those that were G3BP1-associated and PS-depleted, G3BP1-dissociated and PS-enriched, and G3BP1-associated but also PS-enriched. Oxidative stress profoundly altered the partitioning of transcripts between these compartments. Under arsenite stress, G3BP1-associated and PS-depleted transcripts correlated with reduced expression of encoded mitochondrial proteins, PS-enriched transcripts that disassociated from G3BP1 encoded cell cycle and cytoprotective proteins whose expression increased, while transcripts that were both G3BP1-associated and PS-enriched encoded proteins involved in diverse stress response pathways. Therefore, G3BP1 guides transcript partitioning to reprogram mRNA translation and support stress adaptation.

Comparative proteomics analysis of patients with quick development and slow development Chronic Obstructive Pulmonary Disease (COPD)

BACKGROUND

The development of Chronic Obstructive Pulmonary Disease (COPD) has been assessed and divided into slow development (SD), normal development (ND) and quick development (QD). Little is known about the plasma proteome characters among these three phenotypes.

METHODS

We performed a comparative proteomic analysis in the plasma of normal control (NC), SD, ND and QD phenotype COPD patients using isobaric tags for relative and absolute quantitation (iTRAQ) technique.

RESULTS

A total of 683 proteins were successfully identified in the plasma samples, of which 394 were considered as high-quality proteins (95% confidential peptides ≥ 2). Further, a total of 25, 19 and 27 different abundant proteins (DAPs) were identified in SD, ND and QD groups, respectively. Gene ontology (GO) classification analysis of all DAPs showed that immune system process (GO:0002376) were the most significant. The pathway enrichment analysis showed that innate immune response (GO:0045087), receptor-mediated endocytosis (GO:0006898) and proteolysis (GO:0006508) were the branch-end terms. Notably, the 15 QD special DAPs were considered as potential markers for identify patient might have quick development COPD, and thus provided more aggressive treatment strategy for these patients.

CONCLUSION

This work provides an insight into global plasma proteome profiles among the SD, ND and QD phenotypes of COPD patients. The most significant GO terms that the DAPs enriched in were immune system related terms. In addition, the 15 QD specific DPAs provided candidates of potential markers to predict the development types of COPD patients.

IRE1α/NOX4 signaling pathway mediates ROS-dependent activation of hepatic stellate cells in NaAsO2 -induced liver fibrosis

Liver fibrosis is a severe health problem worldwide, and it is characterized by the activation of hepatic stellate cells (HSCs) and excessive deposition of collagen. Prolonged arsenic exposure can induce HSCs activation and liver fibrosis. In the present study, the results showed that chronic NaAsO₂ ingestion could result in liver fibrosis and oxidative stress in Sprague-Dawley rats, along with representative collagen deposition and HSCs activation. In addition, the inositol-requiring enzyme 1α (IRE1α)-endoplasmic reticulum (ER)-stress pathway was activated, and the activity of nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) was upregulated in rat livers. Simultaneously, the excessive production of reactive oxygen species (ROS) could induce HSCs activation, and NOX4 played an important role in generating ROS in vitro. Moreover, ER stress occurred with HSCs activation at the same time under NaAsO₂ exposure, and during ER stress, the IRE1α pathway was responsible for NOX4 activation. Therefore, inhibition of IRE1α activation could attenuate the HSCs activation induced by NaAsO₂ . In conclusion, the present study manifested that inorganic arsenic exposure could activate HSCs through IRE1α/NOX4-mediated ROS generation.

Comparative Proteomic Investigation of Plasma Reveals Novel Potential Biomarker Groups for Acute Aortic Dissection

Acute aortic dissection (AAD) is a catastrophic cardiovascular disease with high disability and mortality due to multiple fatal complications. However, the molecular changes of the serum proteome after AAD are not very clear. Here, we performed isobaric tags for relative and absolute quantitation- (iTRAQ-) based comparative proteomic analysis to investigate the proteome profile changes after AAD by collecting plasma samples from 20 AAD patients and 20 controls. Out of the 345 identified proteins, 266 were considered as high-quality quantified proteins (95%confident peptides ≥ 2), of which 25 proteins were accumulated and 12 were reduced in AAD samples. Gene ontology enrichment analysis showed that the 25 AAD-accumulated proteins were enriched in high-density lipoprotein particles for the cellular component category and protein homodimerization acidity for the molecular function category. Protein-protein interaction network analysis showed that serum amyloid A proteins (SAAs), complement component proteins, and carboxypeptidase N catalytic chain proteins (CPNs) possessed the key nodes of the network. The expression levels of six selected AAD-accumulated proteins, B2-GP1, CPN1, F9, LBP, SAA1, and SAA2, were validated by ELISA. Moreover, ROC analysis showed that the AUCs of B2-GP1 and CPN1 were 0.808 and 0.702, respectively. Our data provide insights into molecular change profiles in proteome levels after AAD and indicate that B2-GP1 and CPN1 are potential biomarkers for AAD.

Autophagic-CTSB-inflammasome axis modulates hepatic stellate cells activation in arsenic-induced liver fibrosis

Long-term exposure to arsenic can cause liver injury and fibrosis. The activation of hepatic stellate cells (HSCs) plays an essential role in the process of liver fibrosis. We found that NaAsO₂ caused liver damage and fibrosis in vivo, accompanied by excessive collagen deposition and HSCs activation. In addition, NaAsO₂ upregulated autophagy flux, elevated the level of cytoplasmic cathepsin B (CTSB), and activated the NOD-like receptors containing pyrin domain 3 (NLRP3) inflammasome in a subtle way. Consistent with these findings in vivo, we demonstrated that NaAsO₂-induced activation of HSCs depended on CTSB-mediated NLRP3 inflammasome activation in HSC-t6 cells and rats primary HSCs. Moreover, inhibition of autophagy decreased the cytoplasmic CTSB and alleviated the activation of the NLRP3 inflammasome, thereby attenuating the NaAsO₂-induced HSCs activation. In summary, these results indicated that NaAsO₂ induced HSCs activation via autophagic-CTSB-NLRP3 inflammasome pathway. These findings may provide a novel insight into the potential mechanism of NaAsO₂-induced liver fibrosis.

iTRAQ-Based Proteomics Analysis of Plasma of Myasthenia Gravis Patients Treated with Jia Wei Bu Zhong Yi Qi Decoction

Myasthenia gravis (MG) is an autoimmune disease. A proportion of MG patients did not get satisfactory results after treatment with pyridostigmine and prednisone. Jia Wei Bu Zhong Yi Qi (Jia Wei BZYQ) decoction, a water extract from multiple herbs, has been demonstrated to be effective in the treatment of multiple "Qi deficiency type" diseases including MG in China. In this text, we investigated protein alterations in the plasma from healthy volunteers (C), MG patients without any treatment (T1), MG patients with routine western medical treatment (T2), and MG patients with combined treatments of Jia Wei BZYQ decoction and routine western medicines (T3) and identified some potential proteins involved in the pathogenesis and treatment of MG. iTRAQ (isobaric tags for relative and absolute quantitation) and 2D-LC-MS/MS (two-dimensional liquid chromatography-tandem mass spectrometry technologies) were employed to screen differentially expressed proteins. The identification, quantification, functional annotation, and interaction of proteins were analyzed by matching software and databases. In our project, 618 proteins were identified, among which 447 proteins had quantitative data. The number of differentially expressed proteins was 110, 117, 143, 115, 86, and 158 in T1 vs. C, T2 vs. C, T2 vs. T1, T3 vs. C, T3 vs. T1, and T3 vs. T2 groups, respectively. Functional annotation results showed that many differentially expressed proteins were closely associated with immune responses. For instance, some key proteins such as C-reactive protein, apolipoprotein C-III, apolipoprotein A-II, alpha-actinin-1, and thrombospondin-1 have been found to be abnormally expressed in T3 group compared to T1 group or T2 group. Interaction network analyses also provided some potential biomarkers or targets for MG management.

Effects of Proanthocyanidins on Arsenic Methylation Metabolism and Efflux in Human Hepatocytes L-02

This study investigated the effects of proanthocyanidins (PC) on arsenic methylation metabolism and efflux in human hepatocytes (L-02), as well as the relationships between PC and GSH, MRP1 and other molecules. Cells were randomly divided into blank control group, arsenic trioxide exposure group (ATO, As₂O₃, 25μmol/L), and PC-treated arsenic exposure group (10, 25, 50mg/L). After 24/48h, the contents of different forms of arsenic were determined, and the methylation indexes were calculated. Intracellular S-adenosyl methionine (SAM), arsenic (+3 oxidation state) methyltransferase (AS3MT), multidrug resistance-associated protein 1 (MRP1), and reduced glutathione (GSH) were ascertained. Changing trends were observed and the correlation between arsenic metabolism and efflux related factors and arsenic metabolites was analyzed. We observed that cells showed increased levels of content/constituent ratio of methyl arsenic, primary/secondary methylation index, methylation growth efficiency/rate, and the difference of methyl arsenic content in cells and culture medium (P<0.05, resp.). Compared with ATO exposure group, the intracellular SAM content in PC-treated group decreased, and the contents of GSH, AS3MT, and MRP1 increased (P<0.05, resp.). There was a positive correlation between the content of intracellular GSH/AS3MT and methyl arsenic. The content of MRP1 was positively correlated with the difference of methyl arsenic content in cell and culture medium; conversely, the SAM content was negatively correlated with intracellular methyl arsenic content (P<0.05, resp.). Taken together, these results prove that PC can promote arsenic methylation metabolism and efflux in L-02 cells, which may be related to the upregulation of GSH, MRP1, and AS3MT levels by PC.