scholarly journals Proatherogenic gut-microbiome metabolite trimethylamine elicits a gut-liver circuit to regulate TMAO metabolism and atherosclerosis via mediation of CREBH

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
Q Su ◽  
S Kaluzny
Keyword(s):  
Cardiovascular Disease ◽  
Gut Microbiome ◽  
Ldl Receptor ◽  
Immunoblotting Analysis ◽  
Metabolic System ◽  
Metabolic Inflammation ◽  
Vldl Remnant ◽  
Factor C ◽  
Metabolomics Analysis

Abstract Introduction In humans, circulating metabolite Trimethylamine N-oxide (TMAO) is closely associated with higher risk of cardiovascular disease. Trimethylamine (TMA), a precursor of TMAO, is produced by gut microbiome using dietary components, i.e., choline and carnitine, as substrates. The gut-derived TMA is then transferred to the liver where it is further oxidized to TMAO by the flavin-containing monooxygenases (FMOs). The ER-resident transcription factor c-AMP responsive element binding protein H (CREBH/CREB3L3) is exclusively expressed in the liver and intestine. Perturbation of CREBH activity contributes to the development of hyperlipidemia and cardiovascular disease. Therefore, the Purpose of this study is to investigate the regulatory effect of a gut bacterium, Akkermansia muciniphila (A. muciniphila), on TMA and TMAO metabolism and the role of CREBH in this process. Methods Two groups of wild type (WT) and CREBH knockout (CREBH-KO) mice were inoculated with 200 μL of A. muciniphila (2×108 cfu/0.2 mL) in PBS or the vehicle (PBS) alone as control every other day through oral gavage for 2 weeks. Plasmas, liver and intestinal tissues were collected for metabolomics analysis, immunoblotting analysis and q-RT-PCR. Results Metabolomics analysis of the plasmas from the experimental mice revealed that increased colonization of A. muciniphila in the gut significantly reduced circulating TMA in the WT mice but not in CREBH-KO mice (P<0.05), suggesting that depletion of CREBH altered the microenvironment of gut microbiome which affected the metabolism of TMA by gut bacteria. In the livers, A. muciniphila treatment markedly reduced mRNA expression of FMO1 and FMO3 (P<0.05), which subsequently inhibited the enzymatic conversion of TMA to TMAO in hepatocytes. Immunoblotting analysis further revealed that LDL receptor was upregulated whereas ER stress markers, GRP94 and JNK1/2, were downregulated in the A. muciniphila treated KO mice, indicating an acceleration in lipoprotein (VLDL remnant) clearance from the circulation and the improvement of metabolic inflammation. In vitro, incubation of mouse hepatocytes AML12 with TMA (600 mM) for 12 hours stimulated expression of FMOs to facilitate the conversion of TMA to TMAO and induced lipotoxicity. Conclusion CREBH mediates the crosstalk between gut microbiome and liver metabolic system that regulates TMA and TMAO metabolism, which contributes to the induction of metabolic inflammation and atherogenesis. This novel finding may lend support to the therapeutic strategy of atherosclerosis. FUNDunding Acknowledgement Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

The Migration of Human Smooth Muscle Cells In Vitro Is Mediated by Plasminogen Activation and Can Be Inhibited by α2-Macroglobulin Receptor Associated Protein

1997 ◽  
Vol 78 (02) ◽  
pp. 880-886 ◽  
Author(s):  
Monique J Wijnberg ◽  
Paul H A Quax ◽  
Nancy M E Nieuwenbroek ◽  
Jan H Verheijen
Keyword(s):  
Smooth Muscle ◽  
Cell Migration ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Ldl Receptor ◽  
Migration And Invasion ◽  
Invasion Assay ◽  
Plasminogen Activation ◽  
Smooth Muscle Cell Migration

SummaryThe plasminogen activation system is thought to be important in cell migration processes. A role for this system during smooth muscle cell migration after vascular injury has been suggested from several animal studies. However, not much is known about its involvement in human vascular remodelling. We studied the involvement of the plasminogen activation system in human smooth muscle cell migration in more detail using an in vitro wound assay and a matrix invasion assay. Inhibition of plasmin activity or inhibition of urokinase-type plasminogen activator (u-PA) activity resulted in approximately 40% reduction of migration after 24 h in the wound assay and an even stronger reduction (70-80%) in the matrix invasion assay. Migration of smooth muscle cells in the presence of inhibitory antibodies against tissue-type plasminogen activator (t-PA) was not significantly reduced after 24 h, but after 48 h a 30% reduction of migration was observed, whereas in the matrix invasion assay a 50% reduction in invasion was observed already after 24 h. Prevention of the interaction of u-PA with cell surface receptors by addition of soluble u-PA receptor or α2-macroglobulin receptor associated protein (RAP) to the culture medium, resulted in a similar inhibition of migration and invasion. From these results it can be concluded that both u-PA and t-PA mediated plasminogen activation can contribute to in vitro human smooth muscle cell migration and invasion. Furthermore, the interaction between u-PA and its cell surface receptor appears also to be involved in this migration and invasion process. The inhibitory effects on migration and invasion by the addition of RAP suggests an involvement of a RAP sensitive receptor of the LDL receptor family, possibly the LDL-receptor related protein (LRP) and/or the VLDL receptor.

Nanodrugs as a new approach in therapy of cardiovascular diseases and cancer with tumor-associated angiogenesis

2020 ◽  
Vol 28 ◽  
Author(s):  
Justyna Hajtuch ◽  
Karolina Niska ◽  
Iwona Inkielewicz-Stepniak
Keyword(s):  
Cardiovascular Disease ◽  
Cardiovascular Diseases ◽  
Controlled Drug Release ◽  
Biological Properties ◽  
Comprehensive Information ◽  
Conventional Drug ◽  
Key Factor ◽  
Functionalized Materials

Background: Cancer along with cardiovascular diseases are globally defined as leading causes of death. Importantly, some risk factors are common to these diseases. The process of angiogenesis and platelets aggregation are observed in cancer development and progression. In recent years, studies have been conducted on nanodrugs in these diseases that have provided important information on the biological and physicochemical properties of nanoparticles. Their attractive features are that they are made of biocompatible, well-characterized and easily functionalized materials. Unlike conventional drug delivery, sustained and controlled drug release can be obtained by using nanomaterials. Methods: In this article, we review the latest research to provide comprehensive information on nanoparticle-based drugs for the treatment of cancer, cardiovascular disease associated with abnormal haemostasis, and the inhibition of tumorassociated angiogenesis. Results: The results of the analysis of data based on nanoparticles with drugs confirm their improved pharmaceutical and biological properties, which gives promising antiplatelet, anticoagulant and antiangiogenic effects. Moreover, the review included in vitro, in vivo research and presented nanodrugs with chemotherapeutics approved by Food and Drug Administration. Conclusion: By the optimization of nanoparticles size and surface properties, nanotechnology are able to deliver drugs with enhanced bioavailability in treatment of cardiovascular disease, cancer and inhibition of cancer-related angiogenesis. Thus, nanotechnology can improve the therapeutic efficacy of the drug, but there is a need for a better understanding of the nanodrugs interaction in the human body, because this is a key factor in the success of potential nanotherapeutics.

Interference of Gold Nanoparticles with In vitro Endotoxin Detection Assays

2020 ◽  
Vol 16 (2) ◽  
pp. 204-213 ◽  
Author(s):  
Melissa A. Vetten ◽  
Mary Gulumian
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Surface Reactivity ◽  
In Vitro Assays ◽  
Limulus Amebocyte Lysate ◽  
Chromogenic Assay ◽  
Nanoparticle Suspensions ◽  
Endotoxin Contamination ◽  
Factor C

Background: Endotoxin-free engineered nanoparticle suspensions are imperative for their successful applications in the field of nanomedicine as well as in the investigations in their toxicity. Gold nanoparticles are known to interfere with various in vitro assays due to their optical properties and potential for surface reactivity. In vitro endotoxin testing assays are known to be susceptible to interference caused by the sample being tested. Objective: This study aimed to identify a preferred assay for the testing of endotoxin contamination in gold nanoparticle suspensions. Methods: The interference by gold nanoparticles on three assays namely, the commonly used limulus amebocyte lysate chromogenic assay, the limulus amebocyte lysate gel-clot method, and the less common recombinant Factor C (rFC) assay, was tested. Results: Possible interference could be observed with all three assays. The interference with the absorbance- based chromogenic assay could not be overcome by dilution; whilst the qualitative nature of the gel-clot assay excluded the possibility of distinguishing between a false positive result due to enhancement of the sensitivity of the assay, and genuine endotoxin contamination. However, interference with the rFC assay was easily overcome through dilution. Conclusion: The rFC assay is recommended as an option for endotoxin contamination detection in gold nanoparticle suspensions.

scholarly journals Eukaryotic clamp loaders and unloaders in the maintenance of genome stability

2020 ◽  
Vol 52 (12) ◽  
pp. 1948-1958
Author(s):  
Kyoo-young Lee ◽  
Su Hyung Park
Keyword(s):  
Dna Damage ◽  
Genomic Instability ◽  
Genome Stability ◽  
Critical Role ◽  
Nuclear Antigen ◽  
Checkpoint Activation ◽  
Sliding Clamp ◽  
Clamp Loaders ◽  
Factor C

AbstractEukaryotic sliding clamp proliferating cell nuclear antigen (PCNA) plays a critical role as a processivity factor for DNA polymerases and as a binding and acting platform for many proteins. The ring-shaped PCNA homotrimer and the DNA damage checkpoint clamp 9-1-1 are loaded onto DNA by clamp loaders. PCNA can be loaded by the pentameric replication factor C (RFC) complex and the CTF18-RFC-like complex (RLC) in vitro. In cells, each complex loads PCNA for different purposes; RFC-loaded PCNA is essential for DNA replication, while CTF18-RLC-loaded PCNA participates in cohesion establishment and checkpoint activation. After completing its tasks, PCNA is unloaded by ATAD5 (Elg1 in yeast)-RLC. The 9-1-1 clamp is loaded at DNA damage sites by RAD17 (Rad24 in yeast)-RLC. All five RFC complex components, but none of the three large subunits of RLC, CTF18, ATAD5, or RAD17, are essential for cell survival; however, deficiency of the three RLC proteins leads to genomic instability. In this review, we describe recent findings that contribute to the understanding of the basic roles of the RFC complex and RLCs and how genomic instability due to deficiency of the three RLCs is linked to the molecular and cellular activity of RLC, particularly focusing on ATAD5 (Elg1).

scholarly journals Xylitol enhances synthesis of propionate in the colon via cross-feeding of gut microbiota

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Shasha Xiang ◽  
Kun Ye ◽  
Mian Li ◽  
Jian Ying ◽  
Huanhuan Wang ◽  
...  
Keyword(s):  
Gut Microbiome ◽  
Lactobacillus Reuteri ◽  
Carbon Sources ◽  
Short Chain Fatty Acids ◽  
Microbial Composition ◽  
Key Enzymes ◽  
Rrna Sequencing ◽  
Phosphate Acetyltransferase

Abstract Background Xylitol, a white or transparent polyol or sugar alcohol, is digestible by colonic microorganisms and promotes the proliferation of beneficial bacteria and the production of short-chain fatty acids (SCFAs), but the mechanism underlying these effects remains unknown. We studied mice fed with 0%, 2% (2.17 g/kg/day), or 5% (5.42 g/kg/day) (weight/weight) xylitol in their chow for 3 months. In addition to the in vivo digestion experiments in mice, 3% (weight/volume) (0.27 g/kg/day for a human being) xylitol was added to a colon simulation system (CDMN) for 7 days. We performed 16S rRNA sequencing, beneficial metabolism biomarker quantification, metabolome, and metatranscriptome analyses to investigate the prebiotic mechanism of xylitol. The representative bacteria related to xylitol digestion were selected for single cultivation and co-culture of two and three bacteria to explore the microbial digestion and utilization of xylitol in media with glucose, xylitol, mixed carbon sources, or no-carbon sources. Besides, the mechanisms underlying the shift in the microbial composition and SCFAs were explored in molecular contexts. Results In both in vivo and in vitro experiments, we found that xylitol did not significantly influence the structure of the gut microbiome. However, it increased all SCFAs, especially propionate in the lumen and butyrate in the mucosa, with a shift in its corresponding bacteria in vitro. Cross-feeding, a relationship in which one organism consumes metabolites excreted by the other, was observed among Lactobacillus reuteri, Bacteroides fragilis, and Escherichia coli in the utilization of xylitol. At the molecular level, we revealed that xylitol dehydrogenase (EC 1.1.1.14), xylulokinase (EC 2.7.1.17), and xylulose phosphate isomerase (EC 5.1.3.1) were key enzymes in xylitol metabolism and were present in Bacteroides and Lachnospiraceae. Therefore, they are considered keystone bacteria in xylitol digestion. Also, xylitol affected the metabolic pathway of propionate, significantly promoting the transcription of phosphate acetyltransferase (EC 2.3.1.8) in Bifidobacterium and increasing the production of propionate. Conclusions Our results revealed that those key enzymes for xylitol digestion from different bacteria can together support the growth of micro-ecology, but they also enhanced the concentration of propionate, which lowered pH to restrict relative amounts of Escherichia and Staphylococcus. Based on the cross-feeding and competition among those bacteria, xylitol can dynamically balance proportions of the gut microbiome to promote enzymes related to xylitol metabolism and SCFAs.

scholarly journals Antiproliferative Activity and Potential Mechanism of Marine-Sourced Streptoglutarimide H against Lung Cancer Cells

Marine Drugs ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 79
Author(s):  
Hengju Ge ◽  
Di Zhang ◽  
Muran Shi ◽  
Xiaoyuan Lian ◽  
Zhizhen Zhang
Keyword(s):  
Lung Cancer ◽  
Cell Cycle ◽  
Cancer Cells ◽  
Antiproliferative Activity ◽  
Lung Cancer Cells ◽  
Potential Mechanism ◽  
Nucleotide Synthesis ◽  
Factor C ◽  
Antiglioma Activity

In 2019, streptoglutarimide H (SGH) was characterized as a new glutarimide from the secondary metabolites produced by a marine-derived actinomycete Streptomyces sp. ZZ741 and shown to have in vitro antiglioma activity. However, the antiproliferative activity and potential mechanism of SGH against lung cancer cells have not yet been characterized. This study demonstrated that SGH significantly inhibited the proliferation of different lung cancer cells. In terms of mechanism of action, SGH downregulated cell cycle- and nucleotide synthesis-related proteins to block cell cycle at G0/G1 phase, reduced the expression levels of glycolytic metabolic enzymes to inhibit glycolysis, and downregulated the important cancer transcription factor c-Myc and the therapeutic target deubiquitinase USP28. Potent anticancer activity and multiple mechanisms indicated SGH to be a novel antitumor compound against lung cancer cells.

scholarly journals Oxidative Stress Biomarkers, Nut-Related Antioxidants, and Cardiovascular Disease

Nutrients ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 682 ◽  
Author(s):  
Julia Lorenzon dos Santos ◽  
Alexandre Schaan de Quadros ◽  
Camila Weschenfelder ◽  
Silvia Bueno Garofallo ◽  
Aline Marcadenti
Keyword(s):  
Oxidative Stress ◽  
Cardiovascular Disease ◽  
Cardiovascular Prevention ◽  
Food Sources ◽  
Dietary Antioxidants ◽  
Oxidative Stress Biomarkers ◽  
Atherosclerosis Progression ◽  
Coronary Syndrome ◽  
Biomarkers Of Oxidative Stress

Atherosclerosis is related to fat accumulation in the arterial walls and vascular stiffening, and results in acute coronary syndrome which is commonly associated with acute myocardial infarction. Oxidative stress participates in the pathogenesis of atherosclerosis. Thus, the inclusion of food sources of dietary antioxidants, such as different kinds of nuts, may improve biomarkers related to oxidative stress, contributing to a possible reduction in atherosclerosis progression. This article has briefly highlighted the interaction between oxidative stress, atherosclerosis, and cardiovascular disease, in addition to the effect of the consumption of different nuts and related dietary antioxidants—like polyphenols and vitamin E—on biomarkers of oxidative stress in primary and secondary cardiovascular prevention. Studies in vitro suggest that nuts may exert antioxidant effects by DNA repair mechanisms, lipid peroxidation prevention, modulation of the signaling pathways, and inhibition of the MAPK pathways through the suppression of NF-κB and activation of the Nrf2 pathways. Studies conducted in animal models showed the ability of dietary nuts in improving biomarkers of oxidative stress, such as oxLDL and GPx. However, clinical trials in humans have not been conclusive, especially with regards to the secondary prevention of cardiovascular disease.

scholarly journals The sugar composition of the fibre in selected plant foods modulates weaning infants’ gut microbiome composition and fermentation metabolites in vitro

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shanthi G. Parkar ◽  
Jovyn K. T. Frost ◽  
Doug Rosendale ◽  
Halina M. Stoklosinski ◽  
Carel M. H. Jobsis ◽  
...  
Keyword(s):  
Gut Microbiome ◽  
Gas Production ◽  
Sugar Composition ◽  
Microbiome Composition ◽  
Fibre Concentration ◽  
Microbiome Profile ◽  
Infant Gut Microbiome ◽  
Immune Health ◽  
Faecal Bacteria

AbstractEight plant-based foods: oat flour and pureed apple, blackcurrant, carrot, gold- and green-fleshed kiwifruit, pumpkin, sweetcorn, were pre-digested and fermented with pooled inocula of weaning infants’ faecal bacteria in an in vitro hindgut model. Inulin and water were included as controls. The pre-digested foods were analysed for digestion-resistant fibre-derived sugar composition and standardised to the same total fibre concentration prior to fermentation. The food-microbiome interactions were then characterised by measuring microbial acid and gas metabolites, microbial glycosidase activity and determining microbiome structure. At the physiologically relevant time of 10 h of fermentation, the xyloglucan-rich apple and blackcurrant favoured a propiogenic metabolic and microbiome profile with no measurable gas production. Glucose-rich, xyloglucan-poor pumpkin caused the greatest increases in lactate and acetate (indicative of high fermentability) commensurate with increased bifidobacteria. Glucose-rich, xyloglucan-poor oats and sweetcorn, and arabinogalactan-rich carrot also increased lactate and acetate, and were more stimulatory of clostridial families, which are indicative of increased microbial diversity and gut and immune health. Inulin favoured a probiotic-driven consortium, while water supported a proteolytic microbiome. This study shows that the fibre-derived sugar composition of complementary foods may shape infant gut microbiome structure and metabolic activity, at least in vitro.

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