ITRAQ-based quantitative proteomic analysis of processed Euphorbia lathyris L. for reducing the intestinal toxicity

The pro-absorptive effect of glycosylated zein-fatty acid complexes on fucoxanthin via the lipid transporter protein delivery pathway

Growing research confirms that lipid transport proteins play a key role in the trans-intestinal epithelial transport of carotenoids. In this study, to simultaneously improve the digestive stability and intestinal absorption of fucoxanthin (FX), functionalized vectors with a capability of up-regulating the expression of FX-specific lipid transporter proteins was fabricated. The results showed that myristic acid, palmitic acid, and stearic acid effectively promoted FX-specific lipid transporter protein expression and formed stable self-assembly complexes with Millard-modified zein (MZ). The FX was sufficiently encapsulated in the MZ-fatty acid (FA) particles, forming spherical nanoparticles with a "core-shell" structure. Simulated gastrointestinal digestion showed that FA introduction significantly increased the FX bioaccessibility. In vivo results further verified that adding FAs dramatically increased the FX serum response concentration. These findings suggest that incorporating nutrients that can promote lipid transporter protein expression into delivery vehicles should be an effective strategy for improving oral carotenoid absorption.

Euphorbia factor L1 inhibited transport channel and energy metabolism in human colon adenocarcinoma cell line Caco-2

Euphorbia factor L1 (EFL1) is a kind of lathyrane-type diterpenoid and is isolated from the medical herb Euphorbia lathyris L. (Euphorbiaceae); it has been reported with the toxicity that causes intestinal irritation, but the underlying mechanisms are still obscure. The objective of this study was to assess the EFL1-induced intestinal cytotoxicity in human colon adenocarcinoma Caco-2 cells. The Caco-2 cells were treated with EFL1, and the intracellular calcium ion concentration, mitochondrial membrane potential (MMP), mitochondrial permeability transition pore (mPTP), adenosine 5'-triphosphate (ATP) content, ATPase activities, TGF-β1 concentration, and transepithelial electrical resistance (TEER) were detected. The interaction between EFL1 and the tight junction proteins Occludin, Claudin-4, Tricellulin, ZO-1, JAM-1, and E-cadherin was simulated by molecular docking. The expression of proteins involved in the energy metabolism, the ion transporters and aquaporins, the tight junction, and the F-actin cytoskeleton were detected by Western blotting and cell immunofluorescence. As a result, EFL1 decreased the intracellular Ca2+, MMP, mPTP, ATP content, and ATPase activities in the Caco-2 cells. The AMPK/SIRT1/PGC-1α signaling pathway, which regulates the energy metabolism, was inhibited. The ion transporters NEH and CFTR, as well as the aquaporins in the Caco-2 cells, were decreased. The tight junction proteins were down-regulated, and the integrity of the intestinal barrier was injured; TGF-β1 was compensatively increased; so, the intestinal permeability was increased and was characterized by decreased TEER. The morphology of the F-actin cytoskeleton was destroyed. These findings indicated that EFL1 caused cytotoxicity in the human intestinal Caco-2 cells through mitochondrial damage, inhibition of the energy metabolism, and suppression of the ion and water molecule transporters, as well as the down-regulation tight junction and cytoskeleton protiens.

Proteomic analysis of metabolic mechanisms associated with fatty acid biosynthesis during Styrax tonkinensis kernel development

BACKGROUND

Styrax tonkinensis is a white-flowered tree with considerable potential as a feedstock source for biodiesel production from the oily seed contained within its nutlike drupes. Transcriptome changes during oil accumulation have been previously reported, but not concurrent changes in the proteome.

RESULTS

Using proteomic analysis of samples collected at 50, 70, 100 and 130 days after flowering (DAF), we identified 1472 differentially expressed proteins (DEPs). Based on their expression patterns, we grouped the DEPs into nine clusters and analyzed the pathway enrichment. Proteins related to starch and sucrose metabolism were most abundant at 50 DAF. Proteins involved in fatty acid (FA) biosynthesis were mainly grouped into a cluster that peaked at 70 DAF. Proteins related to protein processing in endoplasmic reticulum had two major patterns, trending either upwards or downwards, while proteins involved in amino acid biosynthesis showed more complex relationships. We identified 42 key enzymes involved in lipid accumulation during kernel development, including the acetyl-CoA carboxylase complex (ACC) and the pyruvate dehydrogenase complex (PDC). One oil body membrane protein, oleosin, continuously increased during kernel development.

CONCLUSION

A regulatory network of oil accumulation processes was built based on protein and available transcriptome expression data, which were in good temporal agreement. This analysis placed ACC and PDC in the center of the network, suggesting that the glycolytic provision of substrate plays a central regulatory role in FA biosynthesis and oil accumulation. © 2021 Society of Chemical Industry.

Incomptine A Induces Apoptosis, ROS Production and a Differential Protein Expression on Non-Hodgkin's Lymphoma Cells

Sesquiterpene lactones are of pharmaceutical interest due their cytotoxic and antitumor properties, which are commonly found within plants of several genera from the Asteraceae family such as the Decachaeta genus. From Decachaeta incompta four heliangolide, namely incomptines A-D have been isolated. In this study, cytotoxic properties of incomptine A (IA) were evaluated on four lymphoma cancer cell lines: U-937, Farage, SU-DHL-2, and REC-1. The type of cell death induced by IA and its effects on U-937 cells were analyzed based on its capability to induce apoptosis and produce reactive oxygen species (ROS) through flow cytometry with 4′,6-diamidino-2-phenylindole staining, dual annexin V/DAPI staining, and dichlorofluorescein 2′,7′-diacetate, respectively. A differential protein expression analysis study was carried out by isobaric tags for relative and absolute quantitation (iTRAQ) through UPLC-MS/MS. Results reveal that IA exhibited cytotoxic activity against the cell line U-937 (CC₅₀ of 0.12 ± 0.02 μM) and the incubation of these cells in presence of IA significantly increased apoptotic population and intracellular ROS levels. In the proteomic approach 1548 proteins were differentially expressed, out of which 587 exhibited a fold-change ≥ 1.5 and 961 a fold-change ≤ 0.67. Most of these differentially regulated proteins are involved in apoptosis, oxidative stress, glycolytic metabolism, or cytoskeleton structuration.

Comparison of Pharmacokinetics and Tissue Distribution Characteristics of Three Diterpenoid Esters in Crude and Prepared Semen Euphorbiae

Background

Semen Euphorbiae (SE) and Semen Euphorbiae Pulveratum (SEP) have a long history of medicinal use. SEP is the processed product of SE; both ancient and modern studies have shown that SEP has a lower toxicity compared to SE. To clarify the influence of processing on the pharmacological properties of SE and SEP, a study was carried out to compare the pharmacokinetics and distribution characteristics of three active compounds after oral administration of SE and SEP extracts.

Methods

A UPLC-MS/MS method was established to simultaneously determine the contents of Euphorbia factors L₁, L₂, and L₃ in rat plasma and mouse tissues after an oral administration of crude and processed SE with approximately the same dosage. Plasma and heart, liver, spleen, lung, kidney, and colon tissue samples were treated with ethyl acetate and separated by gradient elution on a C18 column with a mobile phase of 0.1% formic acid and methanol.

Results

The established method had good selectivity, linear range, accuracy, precision, stability, matrix effect, and extraction recovery. The area under the concentration time curve, time to maximum concentration, maximum concentration, half-life of elimination, and mean retention time of plasma samples in SEP-treated group decreased, and the clearance in SEP-treated group increased. Moreover, the active component concentrations in colon, liver, and kidney tissues were more followed by those in the heart, lungs, and spleen.

Conclusion

These results indicate that the processing could influence the pharmacokinetics and tissue distribution of Euphorbia factors L₁, L₂, and L₃ after oral administration of crude and processed SE. The data obtained may lay a foundation for the clinical use of SE and for further study on the processing mechanism of SE.

Bacterial dormancy: A subpopulation of viable but non-culturable cells demonstrates better fitness for revival

The viable but non culturable (VBNC) state is a condition in which bacterial cells are viable and metabolically active, but resistant to cultivation using a routine growth medium. We investigated the ability of V. parahaemolyticus to form VBNC cells, and to subsequently become resuscitated. The ability to control VBNC cell formation in the laboratory allowed us to selectively isolate VBNC cells using fluorescence activated cell sorting, and to differentiate subpopulations based on their metabolic activity, cell shape and the ability to cause disease in Galleria mellonella. Our results showed that two subpopulations (P1 and P2) of V. parahaemolyticus VBNC cells exist and can remain dormant in the VBNC state for long periods. VBNC subpopulation P2, had a better fitness for survival under stressful conditions and showed 100% revival under favourable conditions. Proteomic analysis of these subpopulations (at two different time points: 12 days (T12) and 50 days (T50) post VBNC) revealed that the proteome of P2 was more similar to that of the starting microcosm culture (T0) than the proteome of P1. Proteins that were significantly up or down-regulated between the different VBNC populations were identified and differentially regulated proteins were assigned into 23 functional groups, the majority being assigned to metabolism functional categories. A lactate dehydrogenase (lldD) protein, responsible for converting lactate to pyruvate, was significantly upregulated in all subpopulations of VBNC cells. Deletion of the lactate dehydrogenase (RIMD2210633:ΔlldD) gene caused cells to enter the VBNC state significantly more quickly compared to the wild-type, and adding lactate to VBNC cells aided their resuscitation and extended the resuscitation window. Addition of pyruvate to the RIMD2210633:ΔlldD strain restored the wild-type VBNC formation profile. This study suggests that lactate dehydrogenase may play a role in regulating the VBNC state.

Multiomics Profiling Reveals Protective Function of Schisandra Lignans against Acetaminophen-Induced Hepatotoxicity

The action principles of traditional Chinese medicines (TCMs) feature multiactive components, multitarget sites, and weak combination with action targets. In the present study, we performed an integrated analysis of metabonomics, proteomics, and lipidomics to establish a scientific research system on the underlying mechanism of TCMs, and Schisandra lignan extract (SLE) was selected as a model TCM. In metabonomics, several metabolic pathways were found to mediate the liver injury induced by acetaminophen (APAP), and SLE could regulate the disorder of lipid metabolism. The proteomic study further proved that the hepatoprotective effect of SLE was closely related to the regulation of lipid metabolism. Indeed, the results of lipidomics demonstrated that SLE dosing has an obvious callback effect on APAP-induced lipidic profile shift. The contents of 25 diglycerides (DAGs) and 21 triglycerides (TAGs) were enhanced significantly by APAP-induced liver injury, which could further induce liver injury and inflammatory response by upregulating protein kinase C (PKCβ, PKCγ, PKCδ, and PKCθ). The upregulated lipids and PKCs could be reversed to the normal level by SLE dosing. More importantly, phosphatidic acid phosphatase, fatty acid transport protein 5, and diacylglycerol acyltransferase 2 were proved to be positively associated with the regulation of DAGs and TAGs. SIGNIFICANCE STATEMENT: Integrated multiomics was first used to reveal the mechanism of APAP-induced acute liver failure (ALF) and the hepatoprotective role of SLE. The results showed that the ALF caused by APAP was closely related to lipid regulation and that SLE dosing could exert a hepatoprotective role by reducing intrahepatic diglyceride and triglyceride levels. Our research can not only promote the application of multicomponent technology in the study of the mechanism of traditional Chinese medicines but also provide an effective approach for the prevention and treatment of ALF.

Comparative proteomic analysis of the brain and colon in three rat models of irritable bowel syndrome

Background

Irritable bowel syndrome (IBS) has been gradually recognized as a disorder of the brain-gut interaction, but the molecular changes in the brain and colon that occur in disease development remain poorly understood. We employed proteomic analysis to identify differentially expressed proteins in both the brain and colon of three IBS models.

Methods

To explore the relevant protein abundance changes in the brain and colon, isobaric tags for relative and absolute quantitation (iTRAQ), liquid chromatography and tandem mass spectrometry (LC-MS) and Western blotting methods were used in three IBS models, including maternal separation (MS, group B), chronic wrap restraint stress (CWRS, group C) and a combination of MS and CWRS (group D).

Results

We identified 153, 280, and 239 proteins that were common and differentially expressed in the two tissue types of groups B, C and D, respectively; 43 differentially expressed proteins showed the same expression changes among the three groups, including 25 proteins upregulated in the colon and downregulated in the brain, 7 proteins downregulated in the colon and upregulated in the brain, and 3 proteins upregulated and 8 downregulated in both tissues. Gene ontology analysis showed that the differentially expressed proteins were mainly associated with cellular assembly and organization and cellular function and maintenance. Protein interaction network and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that the differentiated proteins were mainly involved in the protein ubiquitination pathway and mitochondrial dysfunction.

Conclusions

Taken together, the data presented represent a comprehensive and quantitative proteomic analysis of the brain and colon in IBS models, providing new evidence of an abnormal brain-gut interaction in IBS. These data may be useful for further investigation of potential targets in the diagnosis and treatment of IBS.

Responses of the proteome in testis of mice exposed chronically to environmentally relevant concentrations of Microcystin-LR

Microcystin-LR (MC-LR), a widespread environmental contaminant, has been shown to have potent acute testicular toxicity. However, magnitudes of toxic effects, induced by MCs, depend on route and magnitude of exposure to the toxin. In the present study, male mice were orally exposed 1, 10 or 100 μg/L MC-LR for 90 or 180 days, and pathological approach and the isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics were employed with testes. Proteomics revealed that a number of differentially altered proteins may be involved in MC-LR-induced chronic testicular toxicity. The biological process analysis indicated the altered proteins played an important role in biological adhesion, cellular process, response to stimulus or rhythmic process. The cellular component analysis revealed that most of the proteins with altered expression associated with cell part, extracellular region, extracellular region part, membrane, membrane part, organelle or organelle part. The molecular function showed that these proteins were critical in molecular transducer activity. Integrity analyses provide first compelling evidence that MC-LR significantly cause dysfunction of blood-testis barrier (BTB) through affecting tight junctions and gap junctions. Moreover, phosphatidylinositol 3-kinase (PI3K)/AKT eventually contributed to injury result from chronic low-level MC-LR treatment. Identification of proteins in testis responsive to MC-LR provides insights into molecular mechanisms of chronic toxicity of MCs.

Effect of Euphorbia factor L1 on intestinal barrier impairment and defecation dysfunction in Caenorhabditis elegans

BACKGROUND

Euphorbia factor L1 (EFL1) is a lathyrane-type diterpenoid from the medicinal herb Euphorbia lathyris L., and has been reported with intestinal toxicity, but the potential mechanisms remain unknown.

PURPOSE

The objective of this study was to investigate the intestinal toxicity of EFL1 and the underlying mechanisms using nematode Caenorhabditis elegans.

METHODS

C. elegans were exposed to 0-200 μM EFL1 for 72 h, then the survival rate, body length and body width, locomotion and chemoreception behavior, intestinal ROS and lipofuscin accumulation, intestinal permeability, and defecation rhythm were detected. The γ-aminobutyric acid（GABA) energic neurons AVL and DVB were shown via green fluorescent protein under a laser scanning confocal microscope. The structure of GABA transporter UNC-47 were predicted by homology modeling, and the interaction between EFL1 and UNC-47 was simulated by molecular docking. The mRNA expression of genes related to oxidative stress, intestinal permeability and defecation after EFL1 exposure were detected by RT-qPCR.

RESULTS

EFL1 did not induce lethality of nematodes. The general toxicity was characterized by abnormal growth, locomotion and chemoreception. The intestinal barrier was leaky, due to down-regulated cell junction and active cation transport. The mean defecation cycle length in nematodes was decreased, relating to disorder vesicular and ion transport, enhanced rhythm behavior and muscle contraction. The dysfunctional defecation also attributed to injured UNC-47 protein, as well as GABAergic neurons AVL and DVB. Excessive ROS and lipofuscin accumulation were observed in intestine, along with activation of antioxidant enzymes of SOD, COQ7 and CAT.

CONCLUSION

This study elucidated the EFL1-induced intestinal toxicity in nematodes, characterized as leaky intestinal barrier and accelerated defecation behavior. The underlying mechanisms were involved in oxidative stress, cell junctions, transportation, rhythm behavior, muscle contraction, and GABAergic neurons.

iTRAQ-based proteomics analysis reveals the deregulated proteins related to liver toxicity induced by melamine with or without cyanuric acid in mice

The administration of melamine alone or its combination with cyanuric acid was shown to have certain liver toxicity. However, the injury mechanism of melamine-related toxicity to liver remains poorly understood. In the present study, we investigated the deregulated proteins related to liver toxicity induced by melamine with or without cyanuric acid in mice using iTRAQ quantitative proteomics technique. A total of 166 proteins were significantly changed by the melamine treatment, of which, 36 proteins were up-regulated and 130 proteins were down-regulated. Whereas, 242 proteins were significantly changed by the combined treatment of melamine and cyanuric acid, of which 81 proteins were up-regulated and 161 proteins were down-regulated. The enriched analysis of GO terms and KEGG pathway on the altered proteins showed that both enriched main GO terms and KEGG pathways appear to be different between the two kinds of treatments: melamine and mixture of melamine and cyanuric acid. Based on western blotting technique, it was confirmed that the expression of three proteins: heat shock protein 70 (HSP70), protein disulphide isomerase 6 (PDIA6) and heat shock 70 kDa protein 4-like (HSPA4L) were agreement with the findings in iTRAQ-Based quantitative analysis. These identified proteins might participate in the regulation of a wide range of biological processes, such as immune and inflammatory function, unfolded proteins response in endoplasmic reticulum, DNA damage, and the apoptosis of liver cells. These results from this study provide a new way to gain insight into the mechanisms of melamine-related toxicity to liver in animals.

Differential proteomics for studying action mechanisms of traditional Chinese medicines

Differential proteomics, which has been widely used in studying of traditional Chinese medicines (TCMs) during the past 10 years, is a powerful tool to visualize differentially expressed proteins and analyzes their functions. In this paper, the applications of differential proteomics in exploring the action mechanisms of TCMs on various diseases including cancers, cardiovascular diseases, diabetes, liver diseases, kidney disorders and obesity, etc. were reviewed. Furthermore, differential proteomics in studying of TCMs identification, toxicity, processing and compatibility mechanisms were also included. This review will provide information for the further applications of differential proteomics in TCMs studies.

Comparative proteomic analysis of Ulva prolifera response to high temperature stress

Background

Ulva prolifera belongs to green macroalgae and is the dominant species of green tide. It is distributed worldwide and is therefore subject to high-temperature stress during the growth process. However, the adaptation mechanisms of the response of U. prolifera to high temperatures have not been clearly investigated yet.

Methods

In this study, isobaric tags for relative and absolute quantitation (iTRAQ) labelling was applied in combination with the liquid chromatography-tandem mass spectrometry (LC-MS/MS) to conduct comparative proteomic analysis of the response of U. prolifera to high-temperature stress and to elucidate the involvement of this response in adaptation mechanisms. Differentially expressed proteins (DEPs) of U. prolifera under high temperature (denote UpHT) compared with the control (UpC) were identified. Bioinformatic analyses including GO analysis, pathway analysis, and pathway enrichment analysis was performed to analyse the key metabolic pathways that underlie the thermal tolerance mechanism through protein networks. Quantitative real-time PCR and western blot were performed to validate selected proteins.

Results

In the present study, 1223 DEPs were identified under high temperature compared with the control, which included 790 up-regulated and 433 down-regulated proteins. The high-temperature stimulus mainly induced the expression of glutathione S-transferase, heat shock protein, ascorbate peroxidase, manganese superoxide dismutase, ubiquitin-related protein, lhcSR, rubisco activase, serine/threonine protein kinase 2, adenylate kinase, Ca²⁺-dependent protein kinase (CDPK), disease resistance protein EDS1, metacaspase type II, NDPK2a, 26S proteasome regulatory subunit, ubiquinone oxidoreductase, ATP synthase subunit, SnRK2s, and cytochrome P450. The down-regulated proteins were photosynthesis-related proteins, glutathione reductase, catalase-peroxidase, thioredoxin, thioredoxin peroxidase, PP2C, and carbon fixation-related proteins. Furthermore, biological index analysis indicated that protein content and SOD activity decreased; the value of Fv/Fm dropped to the lowest point after culture for 96 h. However, APX activity and MDA content increased under high temperature.

Conclusion

The present study implied an increase in proteins that were associated with the stress response, oxidative phosphorylation, the cytokinin signal transduction pathway, the abscisic acid signal transduction pathway, and the glutathione metabolism pathway. Proteins that were associated with photosynthesis, carbon fixation in photosynthesis organisms, and the photosynthesis antenna protein pathway were decreased. These pathways played a pivotal role in high temperature regulation. These novel proteins provide a good starting point for further research into their functions using genetic or other approaches. These findings significantly improve the understanding of the molecular mechanisms involved in the tolerance of algae to high-temperature stress.

Electronic supplementary material

The online version of this article (10.1186/s12953-018-0145-5) contains supplementary material, which is available to authorized users.

Roseburia intestinalis-derived flagellin is a negative regulator of intestinal inflammation

Our previous study showed that the Roseburia intestinalis (R. intestinalis), one of the dominant intestinal bacterial microbiota, was significantly decreased in Crohn's disease patients and protected colon epithelial cells from inflammatory damage. However, the roles of lncRNAs in R. intestinalis flagellin-mediated anti-inflammation remain unclear. In this study, we investigate global lncRNA expression profiles using microarray analysis of ulcerative colitis samples from DSS/Flagellin-challenged mice and identified a Flagellin-induced upregulated lncRNA (HIF1A-AS2). Flagellin induced HIF1A-AS2 expression in a dose- and time-dependent manner via p38-stat1 activation. Selective pharmacological inhibitors of Stat1 and p38, and genetic knockdown of these genes abolished Flagellin-induced HIF1A-AS2 expression. In addition, luciferase reporter assay showed that Flagellin activated HIF1A-AS2 promotor via increasing stat1 phosphorylation. Silencing of HIF1A-AS2 abolished Flagellin-mediated anti-inflammatory effects, evaluating by upregulation of cytokines expression, including TNF-α, IL-1β, IL-6 and IL-12, but not TNFβ. In addition, knockdown of HIF1A-AS2 significantly increased p65 and Jnk phosphorylation, and sufficiently abolished Flagellin-mediated anti-inflammatory affects in vivo. Our study provides new insights into the mechanisms that lncRNAs regulate flagellin-mediated alleviation of colonic inflammation. It is indicated that HIF1A-AS2 may be a modulator of intestinal inflammation and represent a novel target for future therapeutics.