A phloroglucinol from Melicope ptelefolia preserves barrier integrity of lipopolysaccharide-induced endothelial cells: study on junctional proteins and cytoskeleton remodeling

Under normal condition, the endothelial cells form a compact monolayer to line the blood vessel. The integrity of this monolayer can be disrupted by lipopolysaccharide (LPS), where LPS could increase the permeability of the endothelium via dissociation of cell-to-cell junctions and rearrangement of cytoskeleton. Prolonged LPS-induced inflammation may lead to excessive plasma leakage and leukocyte migration, leading to fatal outcomes such as shock and multiple organ dysfunctions. Control on this hallmark of inflammation was suggested as a mean of therapeutic interference to improve inflammation. In this study, we investigated the capability of tHGA on maintaining barrier integrity of LPS-induced endothelial cells. tHGA is a phloroglucinol found in Melicope ptelefolia. The compound was previously proven to have strong therapeutic potential with anti-asthma, anti cancer and anti-inflammatory properties. In murine experimental asthma model, tHGA has been shown to inhibit cytokine secretion and leukocyte infiltration, both of which are hallmarks of LPS-induced inflammation. Therefore, it is highly probable that tHGA may have anti-inflammatory effects on LPS-induced inflammation, Human Umbilical Vein Endothelial Cells (HUVECs) were used as an in vitro representative of endothelial cells. HUVECs were seeded to confluence in cell culture insert, where the cells were pretreated with tHGA and induced with LPS. Tracer dyes or monocytes were then allowed to pass the endothelium to examine severity of vascular leakage. To examine F-actin rearrangement, pretreated HUVECs were stained with Alexa-Fluur 488 Phalloidin prior to microscopic examination. The effect of tHGA on preserving junctional protein expression were examined via Western Blot. tHGA reduced permeability and monocyte transendothelial migration at 5µM and 20µM. Furthermore, tHGA inhibited LPS-induced cytoskeletal rearrangement of HUVECs. Additionally, tHGA is able to preserve the protein expression of F-cadherin and Occludin. tHGA is able to preserve barrier integrity of LPS-induced endothelial cells via preservation of actin cytoskeleton and junctional proteins

Barrier protective effects of 2,4,6-trihydroxy-3-geranyl acetophenone on lipopolysaccharides-stimulated inflammatory responses in human umbilical vein endothelial cells

Pharmocological relevance: 2,4,6-trihydroxy-3-geranyl acetophenone (tHGA), is a phloroglucinol compound found naturally in Melicope ptelefolia. Melicope ptelefolia has been used traditionally for centuries as natural remedy for wound infections and inflammatory diseases. Aim of the study: Endothelial barrier dysfunction is a pathological hallmark of many diseases and can be caused by lipopolysaccharides (LPS) stimulation. Therefore, this study aims to investigate the possible barrier protective effects of tHGA upon LPS-stimulated inflammatory responses in human umbilical vein endothelial cells (HUVECs). Materials and methods: HUVECs were pretreated with tHGA prior to LPS stimulation, where inflammatory parameters including permeability, monocyte adhesion and migration, and release of pro-inflammatory mediators were examined. Additionally, the effect of tHGA on F-actin rearrangement and adhesion protein expression of LPS-stimulated HUVECs was evaluated. Results: It was found that pretreatment with tHGA inhibited monocyte adhesion and transendothelial migration, reduced endothelial hyperpermeability and secretion of prostaglandin E2 (PGE2). Additionally, tHGA inhibited cytoskeletal rearrangement and adhesion protein expression on LPS-stimulated HUVECs. Conclusion: As the regulation of endothelial barrier dysfunction can be one of the therapeutic strategies to improve the outcome of inflammation, tHGA may be able to preserve vascular barrier integrity of endothelial cells following LPS-stimulated dysfunction, thereby endorsing its potential usefulness in vascular inflammatory diseases

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Continuous operation of the potassium-based dry sorbent CO2 capture process with two fluidized-bed reactors

The dry sorbent CO2 capture process is an advanced concept to efficiently remove CO2 from flue gas with two fluidized-bed reactors. This paper summarizes the results of performance of the two fluidized-bed reactors in the continuous solid circulation mode to investigate the feasibility of using potassium carbonate-based solid sorbent (Sorb KX35). The parameters such as gas velocity, solid circulation, carbonation temperature, and water vapor content were investigated during several continuous operations of two fluidized-bed reactors. The CO2 removal increased as gas velocity was decreased and as solid circulation rate was increased. The CO2 removal ranged from 26% to 73% was rather sensitive to the water vapor content among other parameters. A 20 h continuous operation conducted in a bench scale fast fluidized-bed reactor system indicated that the spray-dried potassium-based sorbent, Sorb KX35 having superior attrition resistance and high bulk density, had a promising CO2 removal capacity of 50-73% at steady state and was able to regenerate and reuse. The results from this work are good enough to prove the concept of the dry sorbent CO2 capture process to be one of viable methods for capturing CO2 from dilute flue gas of fossil fuel-fired power plants.close728

Barrier protective effects of 2,4,6-trihydroxy-3-geranyl acetophenone on lipopolysaccharides-stimulated inflammatory responses in human umbilical vein endothelial cells

Pharmocological relevance: 2,4,6-trihydroxy-3-geranyl acetophenone (tHGA), is a phloroglucinol compound found naturally in Melicope ptelefolia. Melicope ptelefolia has been used traditionally for centuries as natural remedy for wound infections and inflammatory diseases. Aim of the study: Endothelial barrier dysfunction is a pathological hallmark of many diseases and can be caused by lipopolysaccharides (LPS) stimulation. Therefore, this study aims to investigate the possible barrier protective effects of tHGA upon LPS-stimulated inflammatory responses in human umbilical vein endothelial cells (HUVECs). Materials and methods: HUVECs were pretreated with tHGA prior to LPS stimulation, where inflammatory parameters including permeability, monocyte adhesion and migration, and release of pro-inflammatory mediators were examined. Additionally, the effect of tHGA on F-actin rearrangement and adhesion protein expression of LPS-stimulated HUVECs was evaluated. Results: It was found that pretreatment with tHGA inhibited monocyte adhesion and transendothelial migration, reduced endothelial hyperpermeability and secretion of prostaglandin E2 (PGE2). Additionally, tHGA inhibited cytoskeletal rearrangement and adhesion protein expression on LPS-stimulated HUVECs. Conclusion: As the regulation of endothelial barrier dysfunction can be one of the therapeutic strategies to improve the outcome of inflammation, tHGA may be able to preserve vascular barrier integrity of endothelial cells following LPS-stimulated dysfunction, thereby endorsing its potential usefulness in vascular inflammatory diseases

A Review of Malaysian Herbal Plants and Their Active Constituents with Potential Therapeutic Applications in Sepsis

Sepsis refers to organ failure due to uncontrolled body immune responses towards infection. The systemic inflammatory response triggered by pathogen-associated molecular patterns (PAMPs), such as lipopolysaccharide (LPS) from Gram-negative bacteria, is accompanied by the release of various proinflammatory mediators that can lead to organ damage. The progression to septic shock is even more life-threatening due to hypotension. Thus, sepsis is a leading cause of death and morbidity globally. However, current therapies are mainly symptomatic treatment and rely on the use of antibiotics. The lack of a specific treatment demands exploration of new drugs. Malaysian herbal plants have a long history of usage for medicinal purposes. A total of 64 Malaysian plants commonly used in the herbal industry have been published in Malaysian Herbal Monograph 2015 and Globinmed website (http://www.globinmed.com/). An extensive bibliographic search in databases such as PubMed, ScienceDirect, and Scopus revealed that seven of these plants have antisepsis properties, as evidenced by the therapeutic effect of their extracts or isolated compounds against sepsis-associated inflammatory responses or conditions in in vitro or/and in vivo studies. These include Andrographis paniculata, Zingiber officinale, Curcuma longa, Piper nigrum, Syzygium aromaticum, Momordica charantia, and Centella asiatica. Among these, Z. officinale is the most widely studied plant and seems to have the highest potential for future therapeutic applications in sepsis. Although both extracts as well as active constituents from these herbal plants have demonstrated potential antisepsis activity, the activity might be primarily contributed by the active constituent(s) from each of these plants, which are andrographolide (A. paniculata), 6-gingerol and zingerone (Z. officinale), curcumin (C. longa), piperine and pellitorine (P. nigrum), biflorin (S. aromaticum), and asiaticoside, asiatic acid, and madecassoside (C. asiatica). These active constituents have shown great antisepsis effects, and further investigations into their clinical therapeutic potential may be worthwhile

The synthetic curcuminoid BHMC restores endotoxin-stimulated HUVEC dysfunction: specific disruption on enzymatic activity of p38 MAPK

2,6-bis-(4-hydroxyl-3-methoxybenzylidine)cyclohexanone (BHMC) has been proven to selectively inhibit the synthesis of proinflammatory mediators in lipopolysaccharide-induced U937 monocytes through specific interruption of p38 Mitogen-Activated Protein Kinase enzymatic activity and improves the survival rate in a murine lethal sepsis model. The present study addressed the effects of BHMC upon lipopolysaccharide-induced endothelial dysfunction in human umbilical vein endothelial cells to determine the underlying mechanisms. The cytotoxicity effect of BHMC on HUVEC were determined by MTT assay. The effects of BHMC on endothelial dysfunction induced by lipopolysaccharide such as endothelial hyperpermeability, monocyte-endothelial adhesion, transendothelial migration, up-regulation of adhesion molecules and chemokines were evaluated. The effects of BHMC at transcriptional and post-translational levels were determined by Reverse Transcriptase-Polymerase Chain Reaction and Western Blots. The mode of action of BHMC was dissected by looking into the activation of Nuclear Factor-kappa B and Mitogen-Activated Protein Kinases. BHMC concentration-dependently reduced endothelial hyperpermeability, leukocyte-endothelial cell adhesion and monocyte transendothelial migration through inhibition of the protein expression of adhesion molecules (Intercellular Adhesion Molecule-1 and Vascular Cell Adhesion Molecule-1) and secretion of chemokines (Monocyte Chemotactic Protein-1) at the transcriptional level. BHMC restored endothelial dysfunction via selective inhibition of p38 Mitogen-Activated Protein Kinase enzymatic activity which indirectly prevents the activation of Nuclear Factor-kappaB and Activator Protein-1 transcription factors. These findings further support earlier observations on the inhibition of BHMC on inflammatory events through specific disruption of p38 Mitogen-Activated Protein Kinase enzymatic activity and provide new insights into the inhibitory effects of BHMC on lipopolysaccharide-induced endothelial dysfunction