Inhibition of nuclear factor-kappaB-mediated adhesion molecule expression in human endothelial cells

Heterogeneous Patterns of Endothelial NF-κB p65 and MAPK c-Jun Activation, Adhesion Molecule Expression, and Leukocyte Recruitment in Lung Microvasculature of Mice with Sepsis

BACKGROUND

Sepsis is an uncontrolled systemic inflammatory response to an infection that can result in acute failure of the function of the lung called acute respiratory distress syndrome. Leukocyte recruitment is an important hallmark of acute lung failure in patients with sepsis. Endothelial cells (EC) participate in this process by facilitating tethering, rolling, adhesion, and transmigration of leukocytes via adhesion molecules on their cell surface. In in vivo studies, endothelial nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65 and mitogen-activated protein kinase (MAPK) c-Jun intracellular signal transduction pathways were reported to regulate the expression of adhesion molecules.

METHODS

Mice underwent cecal ligation and puncture (CLP) to induce polymicrobial sepsis and were sacrificed at different time points up to 72 h after sepsis onset. Immunohistochemistry and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analyses were used to determine the kinetics of nuclear localization of p65 and c-Jun in EC, expression and location of adhesion molecules E-selectin and vascular cell adhesion molecule 1 (VCAM-1). Furthermore, the extent and location of leukocyte recruitment were assessed based on Ly6G staining of neutrophils, cluster determinant (CD) 3 staining of T lymphocytes, and CD68 staining of macrophages.

RESULTS

In all pulmonary microvascular beds, we identified p65 and c-Jun nuclear accumulation in a subset of endothelial cells within the first 24 h after CLP-sepsis initiation. E-selectin protein was expressed in a subset of microvessels at 4 and 7 h after sepsis initiation, while VCAM-1 was expressed in a scattered pattern in alveolar tissue and microvessels, without discernible changes during sepsis development. CLP-induced sepsis predominantly promoted the accumulation of neutrophils and T lymphocytes 4 and 7 h after disease onset. Neutrophil accumulation occurred in all pulmonary microvascular beds, while T lymphocytes were present in alveolar tissue and postcapillary venules. Taken together, nuclear localization of p65 and c-Jun in EC and neutrophil recruitment could be associated with induced E-selectin expression in the pulmonary microvessels in CLP-septic mice at the early stage of the disease. In alveolar capillaries, on the other hand, activation of these molecular pathways and leukocyte accumulation occurred in the absence of E-selectin or VCAM-1.

CONCLUSIONS

Endothelial activation and leukocyte recruitment in sepsis-induced lung injury are regulated by multiple, heterogeneously controlled mechanisms, which vary depending on the type of microvascular bed involved.

Sepsis-Induced myocardial dysfunction: heterogeneity of functional effects and clinical significance

Sepsis is a life-threatening disease state characterized by organ dysfunction and a dysregulated response to infection. The heart is one of the many organs affected by sepsis, in an entity termed sepsis-induced cardiomyopathy. This was initially used to describe a reversible depression in ejection fraction with ventricular dilation but advances in echocardiography and introduction of new techniques such as speckle tracking have led to descriptions of other common abnormalities in cardiac function associated with sepsis. This includes not only depression of systolic function, but also supranormal ejection fraction, diastolic dysfunction, and right ventricular dysfunction. These reports have led to inconsistent definitions of sepsis-induced cardiomyopathy. Just as there is heterogeneity among patients with sepsis, there is heterogeneity in the cardiac response; thus resuscitating these patients with a single approach is likely suboptimal. Many factors affect the heart in sepsis including inflammatory mediators, catecholamine responsiveness, and pathogen related toxins. This review will discuss different functional effects characterized by echocardiographic changes in sepsis and their prognostic and management implications.

Efficacy of CU06-1004 via regulation of inflammation and endothelial permeability in LPS-induced acute lung injury

BACKGROUND

Acute lung injury (ALI) is a life-threatening condition that fundamentally results from inflammation and edema in the lung. There are no effective treatments available for clinical use. Previously, we found that as a leakage blocker CU06-1004 prevents endothelial barrier disruption and enhances endothelial cell survival under inflammatory conditions. In this study, we aimed to elucidate the effect of CU06-1004 in terms of prevention of inflammation and endothelial dysfunction in an ALI mouse model.

METHODS

An ALI model was established that included intraperitoneal administration of LPS. Following LPS administration, survival rates and lung wet/dry ratios were assessed. Histological analysis was performed using hematoxylin and eosin staining. Scanning electron microscopy was used to examine alveolar and capillary morphology. Cytokines such as IL-1β, IL-6, and TNF-α were analyzed using an ELISA assay of bronchoalveolar lavage fluid (BALF) and serum. Neutrophil infiltration was observed in BALF using Wright-Giemsa staining, and myeloperoxidase (MPO) activity was assessed. Pulmonary vascular leakage was confirmed using Evans-blue dye, and the expression of junctional proteins was evaluated using immunofluorescent staining. Expression of adhesion molecules was observed using immunofluorescence staining. NF-κB activation was determined using immunohistochemistry and western blot analysis.

RESULTS

Survival rates and pulmonary edema were ameliorated with CU06-1004 treatment. Administration of CU06-1004 normalized histopathological changes induced by LPS, and alveolar-capillary wall thickening was reduced. Compared with the LPS-challenged group, after CU06-1004 treatment, the infiltration of immune cells was decreased in the BALF, and MPO activity in lung tissue was reduced. Similarly, in the CU06-1004 treatment group, pro-inflammatory cytokines were significantly inhibited in both BALF and serum. Evans-blue leakage was reduced, and the expression of junctional proteins was recovered in the CU06-1004 group. Adhesion molecules were downregulated and NF-κB activation was inhibited after CU06-1004 treatment.

CONCLUSIONS

These results suggested that CU06-1004 had a therapeutic effect against LPS-induced ALI via alleviation of the inflammatory response and protection of vascular integrity.

Formononetin attenuates Aβ25-35-induced adhesion molecules in HBMECs via Nrf2 activation

Brain vascular inflammation plays a crucial role in the pathogenesis of Alzheimer's disease (AD). As a central pathogenic factor in AD, the extracellular buildup of amyloid-β (Aβ) induces brain microvascular endothelial cells activation, impairs endothelial structure and function. Formononetin (FMN) has been reported to protect against Alzheimer's disease (AD) and attenuates vascular inflammation in atherosclerosis. However, its involvement in regulating vascular inflammation of AD has not been investigated. In the study, we found that FMN significantly attenuates Aβ_25-35-induced expression of adhesion molecules, including intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in the human brain microvascular endothelial cells (HBMECs), suggesting that FMN inhibits Aβ_25-35-induced brain endothelial cells inflammatory response. Moreover, we observed that FMN attenuates Aβ_25-35-induced translocation of NFκB (p65) into the nucleus of HBMECs, and found that FMN treatment induces Nrf2 expression and attenuates Nrf2-Keap1 association in a dose-dependent manner in HBMECs. Furthermore, we demonstrated that Nrf2 silencing significantly attenuates FMN-reduced NFκB (p65) activation and nuclear translocation. Lastly, our results showed that FMN treatment attenuates Aβ_25-35-induced adhesion of THP-1 cell to endothelial cell monolayer. Collectively, these findings suggest that FMN attenuates Aβ_25-35-induced activation in human brain microvascular endothelial cells, which at least in part was mediated through Nrf2 pathways.

Vascular endotheliitis associated with infections: Its pathogenetic role and therapeutic implication

Vascular endothelial cells are major participants in and regulators of immune responses and inflammation. Vascular endotheliitis is regarded as a host immune-inflammatory response of the endothelium forming the inner surface of blood vessels in association with a direct consequence of infectious pathogen invasion. Vascular endotheliitis and consequent endothelial dysfunction can be a principle determinant of microvascular failure, which would favor impaired perfusion, tissue hypoxia, and subsequent organ failure. Emerging evidence suggests the role of vascular endotheliitis in the pathogenesis of coronavirus disease 2019 (COVID-19) and its related complications. Thus, once initiated, vascular endotheliitis and resultant cytokine storm cause systemic hyperinflammation and a thrombotic phenomenon in COVID-19, leading to acute respiratory distress syndrome and widespread organ damage. Vascular endotheliitis also appears to be a contributory factor to vasculopathy and coagulopathy in sepsis that is defined as life-threatening organ dysfunction due to a dysregulated response of the host to infection. Therefore, protecting endothelial cells and reversing vascular endotheliitis may be a leading therapeutic goal for these diseases associated with vascular endotheliitis. In this review, we outline the etiological and pathogenic importance of vascular endotheliitis in infection-related inflammatory diseases, including COVID-19, and possible mechanisms leading to vascular endotheliitis. We also discuss pharmacological agents which may be now considered as potential endotheliitis-based treatment modalities for those diseases.

Endothelial Barrier Function and Leukocyte Transmigration in Atherosclerosis

The vascular endothelium is a highly specialized barrier that controls passage of fluids and migration of cells from the lumen into the vessel wall. Endothelial cells assist leukocytes to extravasate and despite the variety in the specific mechanisms utilized by different leukocytes to cross different vascular beds, there is a general principle of capture, rolling, slow rolling, arrest, crawling, and ultimately diapedesis via a paracellular or transcellular route. In atherosclerosis, the barrier function of the endothelium is impaired leading to uncontrolled leukocyte extravasation and vascular leakage. This is also observed in the neovessels that grow into the atherosclerotic plaque leading to intraplaque hemorrhage and plaque destabilization. This review focuses on the vascular endothelial barrier function and the interaction between endothelial cells and leukocytes during transmigration. We will discuss the role of endothelial dysfunction, transendothelial migration of leukocytes and plaque angiogenesis in atherosclerosis.

Gold nanoparticles coated with polyvinylpyrrolidone and sea urchin extracellular molecules induce transient immune activation

We report that the immunogenicity of colloidal gold nanoparticles coated with polyvinylpyrrolidone (PVP-AuNPs) in a model organism, the sea urchin Paracentrotus lividus, can function as a proxy for humans for in vitro immunological studies. To profile the immune recognition and interaction from exposure to PVP-AuNPs (1 and 10 μg mL^-1), we applied an extensive nano-scale approach, including particle physicochemical characterisation involving immunology, cellular biology, and metabolomics. The interaction between PVP-AuNPs and soluble proteins of the sea urchin physiological coelomic fluid (blood equivalent) results in the formation of a protein "corona" surrounding the NPs from three major proteins that influence the hydrodynamic size and colloidal stability of the particle. At the lower concentration of PVP-AuNPs, the P. lividus phagocytes show a broad metabolic plasticity based on the biosynthesis of metabolites mediating inflammation and phagocytosis. At the higher concentration of PVP-AuNPs, phagocytes activate an immunological response involving Toll-like receptor 4 (TLR4) signalling pathway at 24 hours of exposure. These results emphasise that exposure to PVP-AuNPs drives inflammatory signalling by the phagocytes and the resolution at both the low and high concentrations of the PVP-AuNPs and provides more details regarding the immunogenicity of these NPs.

N‑acetyl cysteine protects HUVECs against lipopolysaccharide‑mediated inflammatory reaction by blocking the NF‑κB signaling pathway

The purpose of the study was to explore the potential protective effects of N‑acetylcysteine (NAC) against lipopolysaccharide (LPS)‑induced inflammatory injury to human umbilical vein endothelial cells (HUVECs). It was also assessed whether the underlying mechanism of this protective effect is mediated via suppression of the nuclear factor‑kappa B (NF‑κB) signaling pathway. Cell viability of HUVECs treated with different concentrations of NAC was assessed using Cell Counting Kit‑8 (CCK‑8) assay. The mRNA expression of inflammatory factors [interleukin‑8 (IL‑8), tumor necrosis factor α (TNF‑α), inducible nitric oxide synthase (iNOS), and intercellular cell adhesive molecule 1 (ICAM‑1)] were assessed using real time semi‑quantitative polymerase chain reaction. Protein expression levels of TNF‑α and IL‑8 were assessed using enzyme‑linked immunosorbent assay. Protein expression levels of ICAM‑1 and the NF‑κB signaling pathway were assessed using western blotting. Nitric reductase method was used to quantify nitric oxide (NO) and iNOS. LPS stimulated the production of TNF‑α, IL‑8, NO, and ICAM‑1 by HUVECs. Moreover, LPS induced activation of the NF‑κB signaling pathway and increased the protein expression of phosphorylated p65. However, pretreatment of HUVECs with NAC significantly attenuated the increase in the expression of inflammatory factors and the level of phosphorylated p65; this indicated that NAC prevented the activation of the NF‑κB signaling pathway. The present findings indicated that NAC protects HUVECs against LPS‑mediated inflammatory reaction and alleviates inflammation. The underlying mechanism is related to the NF‑κB signaling pathway. NAC appears to be a promising agent for prevention and treatment of inflammatory diseases.

Indirect effect of PM1 on endothelial cells via inducing the release of respiratory inflammatory cytokines

A large number of epidemiological studies have shown that increased cardiovascular morbidity and mortality are associated with exposure to high concentrations of PM_2.5. One of the ways that PM_2.5 affects the cardiovascular system is through systemic inflammation. Inflammatory cytokines such as TNF-α, IL-1β, IL-6, and IL-8 stimulate endothelial cells, which leads to endothelial dysfunction. Compared with PM_2.5, PM₁ is smaller in size, has a larger surface area and absorbs more toxic substances such as heavy metals, organic compounds, and black carbon. However, the effect of PM₁ on human health is less studied. Here, we used BEAS-2B cells and differentiated THP-1 cells to simulate epithelial cells and macrophages in the lung, respectively. The indirect effect of PM₁ on endothelial cells was studied with a coculture model consisting of two cell lines (BEAS-2B cells and macrophages) in the top compartment and one cell line, human umbilical vein endothelial cells (EA.hy926), in the bottom compartment of a transwell plate. The results showed that PM₁ could promote the release of inflammatory cytokines, including TNF-α and IL-6, from BEAS-2B cells and macrophages. In addition, PM₁ upregulated ICAM-1 expression in EA.hy926 cells through TNF-α/NF-κB signaling pathways, promoting the adhesion of endothelial cells and monocytes, a key event in the initiation of atherosclerosis.

Enhanced Glycolytic Metabolism Contributes to Cardiac Dysfunction in Polymicrobial Sepsis

Background

Cardiac dysfunction is present in >40% of sepsis patients and is associated with mortality rates of up to 70%. Recent evidence suggests that glycolytic metabolism plays a critical role in host defense and inflammation. Activation of Toll-like receptors on immune cells can enhance glycolytic metabolism. This study investigated whether modulation of glycolysis by inhibition of hexokinase will be beneficial to septic cardiomyopathy.

Methods

Male C57B6/J mice were treated with a hexokinase inhibitor (2-deoxy-d-glucose [2-DG], 0.25-2 g/kg, n = 6-8) before cecal ligation and puncture (CLP) induced sepsis. Untreated septic mice served as control. Sham surgically operated mice treated with or without the 2-DG inhibitor served as sham controls. Cardiac function was assessed 6 hours after CLP sepsis by echocardiography. Serum was harvested for measurement of inflammatory cytokines and lactate.

Results

Sepsis-induced cardiac dysfunction was significantly attenuated by administration of 2-DG. Ejection fraction and fractional shortening in 2-DG-treated septic mice were significantly (P < .05) greater than in untreated CLP mice. 2-DG administration also significantly improved survival outcome, reduced kidney and liver injury, attenuated sepsis-increased serum levels of tumor necrosis factor α and interleukin 1β as well as lactate, and enhanced the expression of Sirt1 and Sirt3 in the myocardium, which play an important role in mitochondrial function and metabolism. In addition, 2-DG administration suppresses sepsis-increased expression of apoptotic inducers Bak and Bax as well as JNK phosphorylation in the myocardium.

Conclusions

Glycolytic metabolism plays an important role in mediating sepsis-induced septic cardiomyopathy. The mechanisms may involve regulation of inflammatory response and apoptotic signaling.

Anti-inflammatory effects of dabrafenib in vitro and in vivo

The screening of bioactive compound libraries can be an effective approach for repositioning FDA-approved drugs or discovering new treatments for human diseases (drug repositioning). Drug repositioning refers to the development of existing drugs for new indications. Dabrafenib (DAB) is a B-Raf inhibitor and initially used for the treatment of metastatic melanoma therapy. Here, we tested the possible use of DAB in the treatment of lipopolysaccharide (LPS)-mediated vascular inflammatory responses. The anti-inflammatory activities of DAB were determined by measuring permeability, neutrophils adhesion and migration, and activation of pro-inflammatory proteins in LPS-activated human umbilical vein endothelial cells (HUVECs) and mice. We found that DAB inhibited LPS-induced barrier disruption, expression of cell adhesion molecules (CAMs), and adhesion and transendothelial migration of neutrophils to human endothelial cells. DAB also suppressed LPS-induced hyperpermeability and leukocytes migration in vivo. Furthermore, DAB suppressed the production of tumor necrosis factor-α (TNF-α) or interleukin (IL)-6 and the activation of nuclear factor-κB (NF-κB) or extracellular regulated kinases (ERK) 1/2 by LPS. Moreover, treatment with DAB resulted in reduced LPS-induced lethal endotoxemia. These results suggest that DAB possesses anti-inflammatory functions by inhibiting hyperpermeability, expression of CAMs, and adhesion and migration of leukocytes, thereby endorsing its usefulness as a therapy for vascular inflammatory diseases.

ROS Signaling in the Pathogenesis of Acute Lung Injury (ALI) and Acute Respiratory Distress Syndrome (ARDS)

The generation of reactive oxygen species (ROS) plays an important role for the maintenance of cellular processes and functions in the body. However, the excessive generation of oxygen radicals under pathological conditions such as acute lung injury (ALI) and its most severe form acute respiratory distress syndrome (ARDS) leads to increased endothelial permeability. Within this hallmark of ALI and ARDS, vascular microvessels lose their junctional integrity and show increased myosin contractions that promote the migration of polymorphonuclear leukocytes (PMNs) and the transition of solutes and fluids in the alveolar lumen. These processes all have a redox component, and this chapter focuses on the role played by ROS during the development of ALI/ARDS. We discuss the origins of ROS within the cell, cellular defense mechanisms against oxidative damage, the role of ROS in the development of endothelial permeability, and potential therapies targeted at oxidative stress.

Suppressive effects of pelargonidin on PolyPhosphate-mediated vascular inflammatory responses

Previous reports suggest that human endothelial cells-derived PolyPhosphate (PolyP) is one of the pro-inflammatory mediators. As a well-known red pigment and found in plants, Pelargonidin (PEL) has been known to have several biological activates which are beneficial for human health. This study was undertaken to investigate whether PEL can modulate PolyP-mediated inflammatory responses in human umbilical vein endothelial cells (HUVECs) and in mice. The anti-inflammatory activities of PEL were determined by measuring permeability, leukocytes adhesion and migration, and activation of pro-inflammatory proteins in PolyP-activated HUVECs and mice. In addition, the beneficial effects of PEL on survival rate in PolyP-injected mice. We found that PEL inhibits PolyP-mediated barrier disruption, the expressions of cell adhesion molecules, and leukocyte to HUVEC adhesion/migration. Interestingly, PolyP-induced NF-κB activation and the productions of TNF-α and IL-6 were inhibited by PEL in HUVECs. These anti-inflammatory functions of PEL were confirmed in PolyP injected mice. These results suggest that PEL have therapeutic potential for various systemic inflammatory diseases.

Paeonol promotes microRNA-126 expression to inhibit monocyte adhesion to ox-LDL-injured vascular endothelial cells and block the activation of the PI3K/Akt/NF-κB pathway

Paeonol (2'-hydroxy-4'-methoxyacetophenone) is an active component isolated from the root of Paeonia Suffruticosa Andrews. We previously found that paeonol inhibited vascular cell adhesion molecule-1 (VCAM‑1) expression, and thus may be useful for the prevention and treatment of rabbit atherosclerosis (AS); however, the underlying mechanisms are not yet well known. Recently, microRNAs (miRNAs or miRs) have been reported to play an important role in the pathogenesis of AS. In the present study, we examined the effects of paeonol on miRNA-126 (miR‑126) expression, and its ability to inhibit monocyte adhesion to oxidized low-density lipoprotein (ox-LDL)-injured vascular endothelial cells (VECs). VECs were isolated from the rat thoracic aorta and stimulated with ox-LDL (20 mg/l) in the presence of paeonol. We found that miR‑126 had a lower expression in the ox-LDL-injured VECs, and VCAM‑1 was identified as a target gene of miR‑126. Furthermore, paeonol promoted miR‑126 expression and suppressed VCAM‑1 expression at the mRNA and protein level. It also inhibited monocyte adhesion to ox-LDL-injured VECs through the promotion of miR‑126 expression. Furthermore, it was demonstrated that paeonol blocked the activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/nuclear factor-κB (NF-κB) signaling pathway by promoting miR-126 expression. Taken together, and to the best of our knowledge, the findings of this study provide the first evidence that paeonol promotes miR‑126 expression to inhibit monocyte adhesion to ox-LDL-injured VECs and block the activation of the PI3K/Akt/NF-κB signaling pathway. Our data suggest that miR‑126 plays a crucial role in vascular inflammation and may be an important therapeutic target in the treatment of AS with the use of paeonol.

Inhibitory Effect of Three Diketopiperazines from Marine-Derived Bacteria on HMGB1-Induced Septic Responsesin Vitroandin Vivo

The nucleosomal protein high-mobility group box-1 (HMGB1), which has recently been established as a late mediator of lethal systemic inflammation, has a relatively wide therapeutic window for pharmacological interventions. Compounds produced by marine-derived microbes have been widely investigated for their potential use as bioactive natural products. Cyclic dipeptides, which are also known as diketopiperazines, are molecules that are frequently found in marine-derived microorganisms. While their pharmacological potential has been well established, their biological activities against septic responses have not yet been reported. Here, three diketopiperazines (1–3) isolated from two strains of marine-derived bacteria were investigated for their potential activities against HMGB1-mediated septic responses. The data showed that 1–3 effectively inhibited the lipopolysaccharide (LPS)-induced release of HMGB1 and suppressed the HMGB1-mediated septic responses, including hyperpermeability, leukocyte adhesion and migration, and cell adhesion molecule expression. In addition, 1–3 inhibited the HMGB1-mediated production of tumor necrosis factor-[Formula: see text] (TNF-[Formula: see text] and interleukin (IL)-6 and the activation of nuclear factor-[Formula: see text]B (NF-[Formula: see text]B) and extracellular signal-regulated kinase (ERK) 1 and ERK2. Collectively, these results indicated that 1–3 might act as potential therapeutic agents for various severe vascular inflammatory diseases through the inhibition of the HMGB1 signaling pathway.

MicroRNA-125b Prevents Cardiac Dysfunction in Polymicrobial Sepsis by Targeting TRAF6-Mediated Nuclear Factor κB Activation and p53-Mediated Apoptotic Signaling

BACKGROUND

 This study examined the effect of microRNA-125b (miR-125b) on sepsis-induced cardiac dysfunction.

METHODS

 Mouse hearts were transfected with lentivirus expressing miR-125b (LmiR-125b) 7 days before cecal ligation and puncture (CLP)-induced sepsis. Cardiac function was examined by echocardiography before and 6 hours after CLP (n = 6/group). Survival was monitored following CLP-induced sepsis (n = 12/group).

RESULTS

 LmiR-125b transfection significantly attenuated cardiac dysfunction due to CLP-induced sepsis. Fractional shortening and ejection fraction values were significantly (P < .05) higher in the LmiR-125b-treated CLP group than in the untreated CLP group. Survival outcome in LmiR-125b-transfected septic mice was markedly improved, compared with mice with CLP-induced sepsis. Transfection of LmiR-125b into the heart significantly suppressed the expression of ICAM-1 and VCAM-1, decreased the accumulation of macrophages and neutrophils in the myocardium, and decreased serum levels of tumor necrosis factor α and interleukin 1β by targeting tumor necrosis factor receptor-associated factor 6 (TRAF6)-mediated nuclear factor κB (NF-κB) activation. In addition, sepsis-induced myocardial apoptosis was markedly attenuated by LmiR-125b transfection through suppression of p53, Bax, and Bak1 expression. In vitro transfection of endothelial cells with miR-125b mimics attenuate LPS-induced ICAM-1 and VCAM-1 expression by suppressing TRAF6 and NF-κB activation.

CONCLUSIONS

 Increased myocardial miR-125b expression attenuates sepsis-induced cardiac dysfunction and improves survival. miR-125b may be a target for septic cardiomyopathy.

Ameliorative Effect of Vicenin-2 and Scolymoside on TGFBIp-Induced Septic Responses

Transforming growth factor β-induced protein (TGFBIp) is an extracellular matrix protein whose expression in several cell types is greatly increased by TGF-β. TGFBIp is released by the human umbilical vein endothelial cells (HUVECs) and functions as a mediator of experimental sepsis. Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain in biological processes. In this study, we investigated the antiseptic effects and underlying mechanisms of vicenin-2 and scolymoside, two active compounds in C. subternata against TGFBIp-mediated septic responses in HUVECs and mice. The anti-inflammatory activities of vicenin-2 or scolymoside were determined by measuring permeability, human neutrophils adhesion and migration, and activation of pro-inflammatory proteins in TGFBIp-activated HUVECs and mice. According to the results, vicenin-2 or scolymoside effectively inhibited lipopolysaccharide-induced release of TGFBIp and suppressed TGFBIp-mediated septic responses, such as hyperpermeability, adhesion and migration of leukocytes, and expression of cell adhesion molecules. In addition, vicenin-2 or scolymoside suppressed the production of tumor necrosis factor-α and interleukin 6 and activation of nuclear factor-κB and extracellular regulated kinases 1/2 by TGFBIp. Vicenin-2 or scolymoside reduced cecal ligation and puncture (CLP)-induced septic mortality and pulmonary injury. Collectively, these results indicate that vicenin-2 and scolymoside could be a potential therapeutic agent for treatment of various severe vascular inflammatory diseases via inhibition of the TGFBIp signaling pathway.

Common Genetic Polymorphisms within NFκB-Related Genes and the Risk of Developing Invasive Aspergillosis

Invasive Aspergillosis (IA) is an opportunistic infection caused by Aspergillus, a ubiquitously present airborne pathogenic mold. A growing number of studies suggest a major host genetic component in disease susceptibility. Here, we evaluated whether 14 single-nucleotide polymorphisms within NFκB1, NFκB2, RelA, RelB, Rel, and IRF4 genes influence the risk of IA in a population of 834 high-risk patients (157 IA and 677 non-IA) recruited through a collaborative effort involving the aspBIOmics consortium and four European clinical institutions. No significant overall associations between selected SNPs and the risk of IA were found in this large cohort. Although a hematopoietic stem cell transplantation (HSCT)-stratified analysis revealed that carriers of the IRF4_{rs12203592T/T} genotype had a six-fold increased risk of developing the infection when compared with those carrying the C allele (OR_REC = 6.24, 95%CI 1.25–31.2, P = 0.026), the association of this variant with IA risk did not reach significance at experiment-wide significant threshold. In addition, we found an association of the IRF4_AATC and IRF4_GGTC haplotypes (not including the IRF4_rs12203592T risk allele) with a decreased risk of IA but the magnitude of the association was similar to the one observed in the single-SNP analysis, which indicated that the haplotypic effect on IA risk was likely due to the IRF4_rs12203592 SNP. Finally, no evidence of significant interactions among the genetic markers tested and the risk of IA was found. These results suggest that the SNPs on the studied genes do not have a clinically relevant impact on the risk of developing IA.

Dietary Selenium Supplementation Modulates Growth of Brain Metastatic Tumors and Changes the Expression of Adhesion Molecules in Brain Microvessels

Various dietary agents can modulate tumor invasiveness. The current study explored whether selenoglycoproteins (SeGPs) extracted from selenium-enriched yeast affect tumor cell homing and growth in the brain. Mice were fed diets enriched with specific SeGPs (SeGP40 or SeGP65, 1 mg/kg Se each), glycoproteins (GP40 or GP65, 0.2-0.3 mg/kg Se each) or a control diet (0.2-0.3 mg/kg Se) for 12 weeks. Then, murine Lewis lung carcinoma cells were infused into the brain circulation. Analyses were performed at early (48 h) and late stages (3 weeks) post tumor cell infusion. Imaging of tumor progression in the brain revealed that mice fed SeGP65-enriched diet displayed diminished metastatic tumor growth, fewer extravasating tumor cells and smaller metastatic lesions. While administration of tumor cells resulted in a significant upregulation of adhesion molecules in the early stage of tumor progression, overexpression of VCAM-1 (vascular call adhesion molecule-1) and ALCAM (activated leukocyte cell adhesion molecule) messenger RNA (mRNA) was diminished in SeGP65 supplemented mice. Additionally, mice fed SeGP65 showed decreased expression of acetylated NF-κB p65, 48 h post tumor cell infusion. The results indicate that tumor progression in the brain can be modulated by specific SeGPs. Selenium-containing compounds were more effective than their glycoprotein controls, implicating selenium as a potential negative regulator of metastatic process.

Suppressive effects of methylthiouracil on polyphosphate-mediated vascular inflammatory responses

Drug repositioning is used to discover drug candidates to treat human diseases, through the application of drugs or compounds that are approved for the treatment of other diseases. This method can significantly reduce the time required and cost of discovering new drug candidates for human diseases. Previous studies have reported pro‐inflammatory responses of endothelial cells to the release of polyphosphate (PolyP). In this study, we examined the anti‐inflammatory responses and mechanisms of methylthiouracil (MTU), which is an antithyroid drug, and its effects on PolyP‐induced septic activities in human umbilical vein endothelial cells (HUVECs) and mice. The survival rates, septic biomarker levels, behaviour of human neutrophils and vascular permeability were determined in PolyP‐activated HUVECs and mice. MTU suppressed the PolyP‐mediated vascular barrier permeability, up‐regulation of inflammatory biomarkers, adhesion/migration of leucocytes, and activation and/or production of nuclear factor‐κB, tumour necrosis factor‐α and interleukin‐6. Furthermore, MTU demonstrated protective effects on PolyP‐mediated lethal death and the levels of the related septic biomarkers. Therefore, these results indicated the therapeutic potential of MTU on various systemic inflammatory diseases, such as sepsis or septic shock.

Rutin Inhibits Neuroinflammation and Provides Neuroprotection in an Experimental Rat Model of Subarachnoid Hemorrhage, Possibly Through Suppressing the RAGE-NF-κB Inflammatory Signaling Pathway

As is known to all, neuroinflammation plays a vital role in early brain injury pathogenesis following subarachnoid hemorrhage (SAH). It has been shown that rutin have a property of inhibiting inflammation in many kinds of animal models. However, the effect of rutin on neuroinflammation after SAH remains uninvestigated. In this study, we investigated the potential effects of rutin on neuroinflammation and the underlying mechanism in an experimental rat model of SAH performed by endovascular perforation. Adult male SD rats were randomly divided into three groups, including sham group, SAH + vehicle group and SAH + rutin group (50 mg/kg) intraperitoneally (i.p.) administered at 30 min after SAH. After sacrificed at 24 h after SAH, all rats were examined by following tests, including neurologic scores, blood-brain barrier permeability, brain water content and neuronal cell death in cerebral cortex. The level of inflammation in brain was estimated by means of multiple molecules, including RAGE, NF-κB, and inflammation cytokines. Our results indicated that rutin could significantly downregulate the increased level of REGE, NF-κB and inflammatory cytokines in protein level. In addition, rutin could also ameliorate a series of secondary brain injuries such as brain edema, destruction of blood-brain barrier, neurological deficits and neuronal death. This study indicated that rutin administration had a neuroprotective effect in an experimental rat model of SAH, possibly through inhibiting RAGE-NF-κB mediated inflammation signaling pathway.

Flavanones and Chromones from Salicornia herbacea Mitigate Septic Lethality via Restoration of Vascular Barrier Integrity

Salicornia herbacea is an annual halophytic glasswort that has been employed as a culinary vegetable, salad, and traditional medicinal resource. Chemical investigation of the aerial parts of S. herbacea led to the isolation of two new (1, 2) and known (3) flavanones as well as a new nature-derived (4) and two known chromone derivatives (5, 6). These purified compounds were evaluated for their suppressive potentials against the release of high-mobility group box 1 protein (HMGB1), which has captured attention as a viable target for alleviating serious septic manifestations or septicemia. The phenolic compounds improved the survival rates of cecal ligation and puncture operation (CLP) in murine models, simulating severe septic shock and its related complications, to 40-60%. These results collectively validate that flavanone- and chromone-based secondary metabolites may serve as prospective prodrugs or food additives that may be commercialized for the control of septic complications and lethality.

Anti-inflammatory effects of Baicalin, Baicalein, and Wogonin in vitro and in vivo

Here, three structurally related polyphenols found in the Chinese herb Huang Qui, namely baicalin, baicalein, and wogonin, were examined for its effects on inflammatory responses by monitoring the effects of baicalin, baicalein, and wogonin on lipopolysaccharide (LPS)-mediated vascular inflammatory responses. We found that each compound inhibited LPS-induced barrier disruption, expression of cell adhesion molecules (CAMs), and adhesion/transendothelial migration of monocytes to human endothelial cells. Each compound induced potent inhibition of phorbol-12-myristate 13-acetate and LPS-induced endothelial cell protein C receptor shedding. It also suppressed LPS-induced hyperpermeability and leukocytes migration in vivo. Furthermore, each compound suppressed the production of tumor necrosis factor-α or interleukin-6 and the activation of nuclear factor-κB or extracellular regulated kinases 1/2 by LPS. Moreover, treatment with each compound resulted in reduced LPS-induced lethal endotoxemia. These results suggest that baicalin, baicalein, and wogonin posses anti-inflammatory functions by inhibiting hyperpermeability, expression of CAMs, and adhesion and migration of leukocytes, thereby endorsing its usefulness as a therapy for vascular inflammatory diseases.

Ameliorative Effect of Aspalathin and Nothofagin from Rooibos (Aspalathus linearis) on HMGB1-Induced Septic ResponsesIn VitroandIn Vivo

The ubiquitous nuclear protein, high mobility group box 1 (HMGB1), is released by activated macrophages and human umbilical vein endothelial cells (HUVECs) and functions as a late mediator of experimental sepsis. Aspalathin (Asp) and nothofagin (Not), which have been reported to have anti-oxidant activity, are the two major active dihydrochalcones found in green rooibos. In this study, we investigated the antiseptic effects and underlying mechanisms of Asp and Not against HMGB1-mediated septic responses in HUVECs and mice. The anti-inflammatory activities of Asp and Not were determined by measuring permeability, monocyte adhesion and migration, and activation of proinflammatory proteins in HMGB1-activated HUVECs and mice. According to the results, Asp and Not effectively inhibited lipopolysaccharide (LPS)-induced release of HMGB1, and suppressed HMGB1-mediated septic responses, such as hyperpermeability, adhesion and migration of leukocytes, and expression of cell adhesion molecules. In addition, Asp and Not suppressed the production of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6), the activation of nuclear factor-κB (NF-κB) and extracellular signal-regulated kinases 1 and 2 (ERK1/2) by HMGB1. Collectively, these results indicate that Asp and Not could be potential therapeutic agents for the treatment of various severe vascular inflammatory diseases via the inhibition of the HMGB1 signaling pathway.

Inhibitory effects of polyozellin from Polyozellus multiplex on HMGB1-mediated septic responses

AIM AND OBJECTIVE

The ubiquitous nuclear protein, high-mobility group box 1 (HMGB1), is released by activated macrophages and human umbilical vein endothelial cells (HUVECs) and functions as a late mediator of experimental sepsis. Polyozellin, which has been reported to have a variety of biological activities including antioxidant and anticancer activity, is the major active compound found in edible mushroom (Polyozellus multiplex). In this study, we investigated the antiseptic effects and underlying mechanisms of polyozellin against HMGB1-mediated septic responses in HUVECs and mice.

METHODS

The anti-inflammatory activities of polyozellin were determined by measuring permeability, human neutrophil adhesion and migration, and activation of proinflammatory proteins in HMGB1-activated HUVECs and mice.

RESULTS

According to the results, polyozellin effectively inhibited lipopolysaccharide (LPS)-induced release of HMGB1, and suppressed HMGB1-mediated septic responses, such as hyperpermeability, adhesion and migration of leukocytes, and expression of cell adhesion molecules. In addition, polyozellin suppressed the production of tumor necrosis factor-α and interleukin (IL)-6, and the activation of nuclear factor-κB and extracellular signal-regulated kinases 1/2 by HMGB1.

CONCLUSION

Collectively, these results indicate that P. multiplex containing polyozellin could be commercialized as functional food for preventing and treatment of various severe vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

Anti-septic effects of fisetin in vitro and in vivo

Sepsis is a state of disrupted inflammatory homeostasis that is initiated by infection. High mobility group box 1 (HMGB1) protein acting as a late mediator of severe vascular inflammatory conditions, such as sepsis and endothelial cell protein C receptor (EPCR), is involved in vascular inflammation. Fisetin, an active compound from the family Fabaceae, was reported to have antiviral, neuroprotective, and anti-inflammatory activities. Here, we determined the anti-septic effects of fisetin on HMGB1-mediated inflammatory responses and on the shedding of EPCR in vitro and in vivo, for the first time. First, we monitored the effects of post-treatment fisetin on lipopolysaccharide (LPS) and cecal ligation and puncture (CLP)-mediated release of HMGB1 and HMGB1-mediated regulation of pro-inflammatory responses in human umbilical vein endothelial cells (HUVECs) and septic mice. Post-treatment fisetin was found to suppress LPS-mediated release of HMGB1 and HMGB1-mediated cytoskeletal rearrangements. Fisetin also inhibited HMGB1-mediated hyperpermeability and leukocyte migration in septic mice. Fisetin induced potent inhibition of phorbol-12-myristate 13-acetate (PMA) and CLP-induced EPCR. Fisetin also inhibited the expression and activity of tumor necrosis factor-α converting enzyme, induced by PMA in endothelial cells. In addition, fisetin inhibited the production of tumor necrosis factor-α and the activation of AKT, nuclear factor-κB, and extracellular regulated kinases 1/2 by HMGB1 in HUVECs. Fisetin also down-regulated CLP-induced release of HMGB1, production of interleukin 1β, and reduced septic mortality. Collectively, these results suggest that fisetin may be a candidate therapeutic agent for the treatment of vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

Exendin-4 inhibits HMGB1-induced inflammatory responses in HUVECs and in murine polymicrobial sepsis

Exendin-4 (EX4) has been reported to attenuate myocardial ischemia and reperfusion (I/R) injury and inflammatory and oxidative responses. Nuclear DNA-binding protein high-mobility group box 1 (HMGB1) protein acts as a late mediator of severe vascular inflammatory conditions. However, the effect of EX4 on HMGB1-induced inflammatory response has not been studied. First, we accessed this question by monitoring the effects of posttreatment EX4 on lipopolysaccharide (LPS) and cecal ligation and puncture (CLP)-mediated release of HMGB1 and HMGB1-mediated regulation of proinflammatory responses in human umbilical vein endothelial cells (HUVECs) and septic mice. Posttreatment EX4 was found to suppress LPS-mediated release of HMGB1 and inhibited HMGB1-mediated hyperpermeability and leukocyte migration in septic mice. EX4 also induced downregulation of CLP-induced release of HMGB1, production of IL-6, and mortality. Collectively, these results suggest that EX4 may be regarded as a candidate therapeutic agent for treatment of vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

Oleanolic acid regulates NF-κB signaling by suppressing MafK expression in RAW 264.7 cells

Oxidative stress and inflammation are common to many pathological conditions. Defense mechanisms protect cells from oxidative stress, but can become over-activated following injury and inflammation. NF-κB and Nrf2 transcription factors regulate proinflammatory and antioxidant gene expression, respectively. Studies have shown that many natural dietary compounds regulate NF-κB and Nrf2, preventing inflammation and oxidative stress. Here, we report major compounds of Prunella vulgaris var. lilacina such as rosmarinic acid, oleanolic acid, ursolic acid and caffeic acid as a potential therapeutic for oxidative stress and inflammation. The major compounds exhibited high anti-inflammatory activity, inhibiting NO, PGE2 production, NF-κB expression and activating Nrf2 expression. In addition, we examined the effect of major compounds on MafK expression. Among the compounds, oleanolic acid significantly decreased MafK expression and MafK-mediated p65 acetylation. These findings suggest that oleanolic acid as NF-κB inhibitors can potentially be used in therapeutic applications for the treatment of oxidative stressnduced diseases. [BMB Reports 2014; 47(9): 524-529]

Antiseptic effect of vicenin-2 and scolymoside from Cyclopia subternata (honeybush) in response to HMGB1 as a late sepsis mediator in vitro and in vivo

Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain. In this study, we investigated the antiseptic effects and underlying mechanisms of vicenin-2 and scolymoside, which are 2 active compounds from C. subternata that act against high mobility group box 1 (HMGB1)-mediated septic responses in human umbilical vein endothelial cells (HUVECs) and mice. The antiseptic activities of vicenin-2 and scolymoside were determined by measuring permeability, neutrophil adhesion and migration, and activation of proinflammatory proteins in HMGB1-activated HUVECs and mice. According to the results, vicenin-2 and scolymoside effectively inhibited lipopolysaccharide-induced release of HMGB1, and suppressed HMGB1-mediated septic responses such as hyperpermeability, the adhesion and migration of leukocytes, and the expression of cell adhesion molecules. In addition, vicenin-2 and scolymoside suppressed the production of tumor necrosis factor-α and interleukin 6, and activation of nuclear factor-κB and extracellular regulated kinases 1/2 by HMGB1. Collectively, these results indicate that vicenin-2 and scolymoside could be a potential therapeutic agents for the treatment of various severe vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

Thiram activates NF-kappaB and enhances ICAM-1 expression in human microvascular endothelial HMEC-1 cells

Thiram (TMTD) is a fungicidal and bactericidal agent used as antiseptic, seed disinfectant and animal repellent. In the light of known properties, thiram is considered to be used as an inhibitor of angiogenesis and/or inflammation. Since angiogenesis requires the growth of vascular endothelial cells we have used microvascular endothelial cell line HMEC-1 to elucidate the effect of thiram on normal and stimulated cells. We cultured HMEC-1 cells in the presence of thiram at low concentration (0.5 µg/mL or 2 µg/mL) (0.2 µM or 0.8 µM) or TNF-α (10 ng/mL) alone, and thiram together with TNF-α. TNF-α was used as a cytokine that triggers changes characteristic for inflammatory state of the cell. We carried out an in vitro study aimed at assessing generation of reactive oxygen species (ROS), activation of NF-κB, and expression of cell adhesion molecules ICAM-1, VCAM-1, PECAM-1. It was found that TMTD produced ROS and activated NF-κB. Activation of NF-κB was concurrent with an increase in ICAM-1 expression on the surface of HMEC-1 cells. ICAM-1 reflects intensity of inflammation in endothelial cell milieu. The expression of VCAM-1 and PECAM-1 on these cells was not changed by thiram. It was also found that stimulation of the HMEC-1 cells with the pro-inflammatory cytokine TNF-α caused activation of ICAM-1 and VCAM-1 expression with concomitant decrease of PECAM-1 cell surface expression above the control levels. Treatment with thiram and TNF-α changed cellular response compared with effects observed after treatment with TNF-α alone, i.e. further increase of ICAM-1 expression and impairment of the TNF-α effect on PECAM-1 and VCAM-1 expression. This study demonstrated that thiram acts as a pro-oxidant, and elicits in endothelial cell environment effects characteristic for inflammation. However, when it is present concurrently with pro-inflammatory cytokine TNF-α interferes with its action.