TNFR1-induced NF-kappaB, but not ERK, p38MAPK or JNK activation, mediates TNF-induced ICAM-1 and VCAM-1 expression on endothelial cells

Krüppel-like factor 2 is an endoprotective transcription factor in diabetic kidney disease

Diabetic kidney disease (DKD) is a microvascular complication of diabetes, and glomerular endothelial cell (GEC) dysfunction is a key driver of DKD pathogenesis. Krüppel-like factor 2 (KLF2), a shear stress-induced transcription factor, is among the highly regulated genes in early DKD. In the kidney, KLF2 expression is mostly restricted to endothelial cells, but its expression is also found in immune cell subsets. KLF2 expression is upregulated in response to increased shear stress by the activation of mechanosensory receptors but suppressed by inflammatory cytokines, both of which characterize the early diabetic kidney milieu. KLF2 expression is reduced in progressive DKD and hypertensive nephropathy in humans and mice, likely due to high glucose and inflammatory cytokines such as TNF-α. However, KLF2 expression is increased in glomerular hyperfiltration-induced shear stress without metabolic dysregulation, such as in settings of unilateral nephrectomy. Lower KLF2 expression is associated with CKD progression in patients with unilateral nephrectomy, consistent with its endoprotective role. KLF2 confers endoprotection by inhibition of inflammation, thrombotic activation, and angiogenesis, and thus KLF2 is considered a protective factor for cardiovascular disease (CVD). Based on similar mechanisms, KLF2 also exhibits renoprotection, and its reduced expression in endothelial cells worsens glomerular injury and albuminuria in settings of diabetes or unilateral nephrectomy. Thus KLF2 confers endoprotective effects in both CVD and DKD, and its activators could potentially be developed as a novel class of drugs for cardiorenal protection in diabetic patients.

Role of non-coding RNAs and exosomal non-coding RNAs in vasculitis: A narrative review

A category of very uncommon systemic inflammatory blood vessel illnesses known as vasculitides. The pathogenesis and etiology of vasculitis are still poorly known. Despite all of the progress made in understanding the genetics and causes behind vasculitis, there is still more to learn. Epigenetic dysregulation is a significant contributor to immune-mediated illnesses, and epigenetic aberrancies in vasculitis are becoming more widely acknowledged. Less than 2 % of the genome contains protein-encoding DNA. Studies have shown that a variety of RNAs originating from the non-coding genome exist. Long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs) have attracted the most attention in recent years as they are becoming more and more important regulators of different biological processes, such as diseases of the veins. Extracellular vehicles (EVs) such as exosomes, are membrane-bound vesicular structures that break free either during programmed cell death, such as apoptosis, pyroptosis, and necroptosis or during cell activation. Exosomes may be involved in harmful ways in inflammation, procoagulation, autoimmune reactions, endothelial dysfunction/damage, intimal hyperplasia and angiogenesis, all of which may be significant in vasculitis. Herein, we summarized various non-coding RNAs that are involved in vasculitides pathogenesis. Moreover, we highlighted the role of exosomes in vasculitides.

Pathogenesis of Extraarticular Manifestations in Rheumatoid Arthritis-A Comprehensive Review

Rheumatoid arthritis (RA) is among the most prevalent and debilitating autoimmune inflammatory chronic diseases. Although it is primarily characterized by destructive peripheral arthritis, it is a systemic disease, and RA-related extraarticular manifestations (EAMs) can affect almost every organ, exhibit a multitude of clinical presentations, and can even be asymptomatic. Importantly, EAMs largely contribute to the quality of life and mortality of RA patients, particularly substantially increased risk of cardiovascular disease (CVD) which is the leading cause of death in RA patients. In spite of known risk factors related to EAM development, a more in-depth understanding of its pathophysiology is lacking. Improved knowledge of EAMs and their comparison to the pathogenesis of arthritis in RA could lead to a better understanding of RA inflammation overall and its initial phases. Taking into account that RA is a disorder that has many faces and that each person experiences it and responds to treatments differently, gaining a better understanding of the connections between the joint and extra-joint manifestations could help to create new treatments and improve the overall approach to the patient.

E3 Ubiquitin Ligase Midline 1 Regulates Endothelial Cell ICAM-1 Expression and Neutrophil Adhesion in Abdominal Sepsis

Septic lung damage is associated with endothelial cell and neutrophil activation. This study examines the role of the E3 ubiquitin ligase midline 1 (Mid1) in abdominal sepsis. Mid1 expression was increased in endothelial cells derived from post-capillary venules in septic mice and TNF-α challenge increased Mid1 levels in endothelial cells in vitro. The siRNA-mediated knockdown of Mid1 decreased TNF-α-induced upregulation of ICAM-1 and neutrophil adhesion to endothelial cells. Moreover, Mid1 silencing reduced leukocyte adhesion in post-capillary venules in septic lungs in vivo. The silencing of Mid1 not only decreased Mid1 expression but also attenuated expression of ICAM-1 in lungs from septic mice. Lastly, TNF-α stimulation decreased PP2Ac levels in endothelial cells in vitro, which was reversed in endothelial cells pretreated with siRNA directed against Mid1. Thus, our novel data show that Mid1 is an important regulator of ICAM-1 expression and neutrophil adhesion in vitro and septic lung injury in vivo. A possible target of Mid1 is PP2Ac in endothelial cells. Targeting the Mid1-PP2Ac axis may be a useful way to reduce pathological lung inflammation in abdominal sepsis.

Soybean-Derived Tripeptide Leu-Ser-Trp (LSW) Protects Human Vascular Endothelial Cells from TNFα-Induced Oxidative Stress and Inflammation via Modulating TNFα Receptors and SIRT1

Soybean is a rich source of high-quality proteins and an excellent food source of bioactive peptides. A tripeptide, Leu−Ser−Trp (LSW), was previously identified from soybean as an angiotensin-converting enzyme inhibitory peptide. In the present work, we further studied its antioxidant and anti-inflammatory activities in human vascular endothelial cells (EA.hy926) and elucidated the mechanisms underlying these biological activities. In tumor necrosis factor alpha (TNFα)-stimulated EA.hy926 cells, LSW significantly inhibited oxidative stress, both reduced superoxide and malondialdehyde levels (p < 0.001), owing to its free-radical-scavenging ability. LSW treatment also mitigated the elevated protein expression of vascular adhesion molecule-1 (p < 0.001) and cyclooxygenase 2 (p < 0.01) via inhibition of NF-κB and p38/JNK signaling, respectively. Additionally, LSW also inhibited the endogenous formation of TNFα and attenuated the expression of its two receptors in EA.hy926 cells. Furthermore, LSW upregulated sirtuin-1 level, which partially contributed to its anti-inflammatory activity. These results demonstrate the multiple roles of LSW in ameliorating vascular endothelial oxidative stress and inflammatory responses, which support its uses as a nutraceutical or functional food ingredient for combating endothelial dysfunction and cardiovascular diseases.

Effect of sulfasalazine on endothelium-dependent vascular response by the activation of Nrf2 signalling pathway

Background: Diabetes mellitus leads to endothelial dysfunction and accumulation of oxygen radicals. Sulfasalazine-induced Nrf2 activation reduces oxidative stress in vessels. Thus, in the present study, we investigated the effects of sulfasalazine on endothelial dysfunction induced by high glucose. We also ascribed the underlying mechanism involved in glucose-induced endothelial dysfunction.

Methods: For this experiment we used 80 Wistar Albino rats thoracic aorta to calculate the dose response curve of noradrenaline and acetylcholine. Vessels were incubated in normal and high glucose for 2 h. To investigate glucose and sulfasalazine effects the vessels of the high glucose group were pre-treated with sulfasalazine (300 mM), JNK inhibitor (SP600125), and ERK inhibitor (U0126) for 30 min. The dose response curve was calculated through organ bath. The eNOS, TAS, TOS, and HO-1 levels were estimated by commercially available ELISA kits.

Results: In the high glucose group, the E_max for contraction was significantly higher (p < 0.001), and E_max for relaxation was lower than that of control. These functional changes were parallel with the low levels of eNOS (p < 0.05). High glucose vessel treated with sulfasalazine showed low E_max value for contraction (p < 0.001) however, the E_max for relaxation was significantly high (p < 0.001) when compared to high glucose group. In the JNK group, E_max for contraction and relaxation was inhibited (p < 0.001) compared to sulfasalazine treated vessels. HO—1 enzyme levels were significantly low (p < 0.01) with sulfasalazine but higher with ERK inhibitor (p < 0.05).

Conclusion: High glucose induced endothelial dysfunction and sulfasalazine reduced damage in high glucose vessels by activating eNOS, antioxidant effect through HO-1 enzymes and particularly inducing Nrf2 via the ERK and JNK pathways.

High Fluid Shear Stress Inhibits Cytokine‐Driven Smad2/3 Activation in Vascular Endothelial Cells

Background

Atherosclerosis occurs preferentially in regions of low and disturbed fluid shear stress (FSS) but is limited in regions of high laminar FSS as a result of inhibition of endothelial inflammatory pathways. Recent work has identified endothelial to mesenchymal transition (EndMT) driven by TGFβ2 (transforming growth factor beta 2)–Smad2/3 (mothers against decapentaplegic) signaling as a critical component of atherogenesis. However, interactions between FSS and EndMT in this context have not been investigated.

Methods and Results

Endothelial cells were treated with TGFβ2 and inflammatory cytokines (interleukin 1β and tumor necrosis factor alpha) with or without high FSS in a parallel plate flow chamber. Smad2/3 nuclear translocation and target gene expression, assayed by immunofluorescence and quantitative polymerase chain reaction, revealed that high FSS blocked the Smad2/3‐EndMT pathway. In vivo, mice were injected with TGFβ2 and inflammatory cytokines, then regions of the aorta under low versus high FSS were examined. TGFβ2 and inflammatory cytokine treatment stimulated Smad2/3 nuclear translocation and target gene expression predominantly in regions of low FSS with little effect in regions of high FSS.

Conclusions

High FSS inhibits endothelial Smad2/3 activation and EndMT in response to inflammatory mediators, resulting in selective EndMT at athero‐susceptible, low FSS regions of arteries.

Lysophosphatidic Acid Is a Proinflammatory Stimulus of Renal Tubular Epithelial Cells

Chronic kidney disease (CKD) refers to a spectrum of diseases defined by renal fibrosis, permanent alterations in kidney structure, and low glomerular-filtration rate. Prolonged epithelial-tubular damage involves a series of changes that eventually lead to CKD, highlighting the importance of tubular epithelial cells in this process. Lysophosphatidic acid (LPA) is a bioactive lipid that signals mainly through its six cognate LPA receptors and is implicated in several chronic inflammatory pathological conditions. In this report, we have stimulated human proximal tubular epithelial cells (HKC-8) with LPA and 175 other possibly pathological stimuli, and simultaneously detected the levels of 27 intracellular phosphoproteins and 32 extracellular secreted molecules with multiplex ELISA. This quantification revealed a large amount of information concerning the signaling and the physiology of HKC-8 cells that can be extrapolated to other proximal tubular epithelial cells. LPA responses clustered with pro-inflammatory stimuli such as TNF and IL-1, promoting the phosphorylation of important inflammatory signaling hubs, including CREB1, ERK1, JUN, IκΒα, and MEK1, as well as the secretion of inflammatory factors of clinical relevance, including CCL2, CCL3, CXCL10, ICAM1, IL-6, and IL-8, most of them shown for the first time in proximal tubular epithelial cells. The identified LPA-induced signal-transduction pathways, which were pharmacologically validated, and the secretion of the inflammatory factors offer novel insights into the possible role of LPA in CKD pathogenesis.

Chicken muscle protein-derived peptide VVHPKESF reduces TNFα-induced inflammation and oxidative stress by suppressing TNFR1 signaling in human vascular endothelial cells

SCOPE

This study aimed to investigate the protective effects of four chicken muscle-derived peptides (Val-Arg-Pro (VRP), Leu-Lys-Tyr (LKY), Val-Arg-Tyr (VRY), and Val-Val-His-Pro-Lys-Glu-Ser-Phe [VVHPKESF (V-F)] on tumor necrosis factor alpha (TNFα)-induced endothelial inflammation and oxidative stress in human vascular endothelial EA.hy926 cells.

METHODS AND RESULTS

Inflammation and oxidative stress are induced in EA.hy926 cells by TNFα (10 ng/mL) treatment for different periods of time. Inflammatory proteins and signaling molecules including inducible nitric oxide synthase, intracellular cell adhesion molecule-1, vascular cell adhesion molecule-1 (VCAM-1), cyclooxygenase 2 (COX2), nuclear factor kappa B (NF-κB), mitogen-activated protein kinases (MAPKs), and TNFα receptor 1 (TNFR1) were measured by qRT-PCR or western blotting; soluble TNFR1 level and NADPH oxidase activity were determined by Elisa kits; superoxide was measured by dihydroethidium staining. Only V-F treatment inhibited the expression of VCAM-1 and COX2, via suppressing NF-κB and p38 MAPK signaling, respectively, while reduced oxidative stress via the inhibition of NADPH oxidase activity; V-F treatment attenuated both gene and protein expressions of TNFR1.

CONCLUSION

V-F treatment ameliorated TNFα-induced endothelial inflammation and oxidative stress possibly via the inhibition of TNFR1 signaling, suggesting its potential as a functional food ingredient or nutraceutical in the prevention and treatment of hypertension and cardiovascular diseases. This article is protected by copyright. All rights reserved.

N-Glycosylation and Inflammation; the Not-So-Sweet Relation

Chronic inflammation is the main feature of many long-term inflammatory diseases such as autoimmune diseases, metabolic disorders, and cancer. There is a growing number of studies in which alterations of N-glycosylation have been observed in many pathophysiological conditions, yet studies of the underlying mechanisms that precede N-glycome changes are still sparse. Proinflammatory cytokines have been shown to alter the substrate synthesis pathways as well as the expression of glycosyltransferases required for the biosynthesis of N-glycans. The resulting N-glycosylation changes can further contribute to disease pathogenesis through modulation of various aspects of immune cell processes, including those relevant to pathogen recognition and fine-tuning the inflammatory response. This review summarizes our current knowledge of inflammation-induced N-glycosylation changes, with a particular focus on specific subsets of immune cells of innate and adaptive immunity and how these changes affect their effector functions, cell interactions, and signal transduction.

Unlocking the Untapped Potential of Endothelial Kinase and Phosphatase Involvement in Sepsis for Drug Treatment Design

Sepsis is a devastating clinical condition that can lead to multiple organ failure and death. Despite advancements in our understanding of molecular mechanisms underlying sepsis and sepsis-associated multiple organ failure, no effective therapeutic treatment to directly counteract it has yet been established. The endothelium is considered to play an important role in sepsis. This review highlights a number of signal transduction pathways involved in endothelial inflammatory activation and dysregulated endothelial barrier function in response to sepsis conditions. Within these pathways – NF-κB, Rac1/RhoA GTPases, AP-1, APC/S1P, Angpt/Tie2, and VEGF/VEGFR2 – we focus on the role of kinases and phosphatases as potential druggable targets for therapeutic intervention. Animal studies and clinical trials that have been conducted for this purpose are discussed, highlighting reasons why they might not have resulted in the expected outcomes, and which lessons can be learned from this. Lastly, opportunities and challenges that sepsis and sepsis-associated multiple organ failure research are currently facing are presented, including recommendations on improved experimental design to increase the translational power of preclinical research to the clinic.

Dichotomous Role of Tumor Necrosis Factor in Pulmonary Barrier Function and Alveolar Fluid Clearance

Alveolar-capillary leak is a hallmark of the acute respiratory distress syndrome (ARDS), a potentially lethal complication of severe sepsis, trauma and pneumonia, including COVID-19. Apart from barrier dysfunction, ARDS is characterized by hyper-inflammation and impaired alveolar fluid clearance (AFC), which foster the development of pulmonary permeability edema and hamper gas exchange. Tumor Necrosis Factor (TNF) is an evolutionarily conserved pleiotropic cytokine, involved in host immune defense against pathogens and cancer. TNF exists in both membrane-bound and soluble form and its mainly -but not exclusively- pro-inflammatory and cytolytic actions are mediated by partially overlapping TNFR1 and TNFR2 binding sites situated at the interface between neighboring subunits in the homo-trimer. Whereas TNFR1 signaling can mediate hyper-inflammation and impaired barrier function and AFC in the lungs, ligand stimulation of TNFR2 can protect from ventilation-induced lung injury. Spatially distinct from the TNFR binding sites, TNF harbors within its structure a lectin-like domain that rather protects lung function in ARDS. The lectin-like domain of TNF -mimicked by the 17 residue TIP peptide- represents a physiological mediator of alveolar-capillary barrier protection. and increases AFC in both hydrostatic and permeability pulmonary edema animal models. The TIP peptide directly activates the epithelial sodium channel (ENaC) -a key mediator of fluid and blood pressure control- upon binding to its α subunit, which is also a part of the non-selective cation channel (NSC). Activity of the lectin-like domain of TNF is preserved in complexes between TNF and its soluble TNFRs and can be physiologically relevant in pneumonia. Antibody- and soluble TNFR-based therapeutic strategies show considerable success in diseases such as rheumatoid arthritis, psoriasis and inflammatory bowel disease, but their chronic use can increase susceptibility to infection. Since the lectin-like domain of TNF does not interfere with TNF's anti-bacterial actions, while exerting protective actions in the alveolar-capillary compartments, it is currently evaluated in clinical trials in ARDS and COVID-19. A more comprehensive knowledge of the precise role of the TNFR binding sites versus the lectin-like domain of TNF in lung injury, tissue hypoxia, repair and remodeling may foster the development of novel therapeutics for ARDS.

Benzo(α)pyrene induces oxidative stress and inflammation in human vascular endothelial cells through AhR and NF-κB pathways

Exposure to polycyclic aromatic hydrocarbons (PAHs) contributes to development and exacerbation of atherosclerosis and cardiovascular disease. However, the underlying molecular mechanisms remain elusive. In the current study, the effect of benzo(α)pyrene (BaP) in human umbilical vein endothelial cells (HUVECs) was investigated, including its impact on apoptosis, cell viability, oxidative stress and inflammatory cytokine release. The role of aryl hydrocarbon receptor (AhR) and NF-κB signaling pathways involved in BaP-induced oxidative stress and inflammation was further investigated. Exposure to BaP induced cell apoptosis and terminal oxidative stress and inflammation responses in HUVECs. BaP also increased the expression of ICAM-1 and VCAM-1. Furthermore, BaP treatment of HUVECs activated AhR and NF-κB signaling pathways, and promoted reactive oxygen species generation and inflammatory cytokine release. The current findings suggest that BaP induced inflammatory cytokine release from HUVECs through oxidative stress accompanied with AhR and NF-κB pathway activation.

Oncolytic Vaccinia Virus Gene Modification and Cytokine Expression Effects on Tumor Infection, Immune Response, and Killing

Oncolytic vaccinia viruses have promising efficacy and safety profiles in cancer therapy. Although antitumor activity can be increased by manipulating viral genes, the relative efficacy of individual modifications has been difficult to assess without side-by-side comparisons. This study sought to compare the initial antitumor activity after intravenous administration of five vaccinia virus variants of the same Western Reserve backbone and thymidine kinase gene deletion in RIP-Tag2 transgenic mice with spontaneous pancreatic neuroendocrine tumors. Tumors had focal regions of infection at 5 days after all viruses. Natural killer (NK) cells were restricted to these sites of infection, but CD8⁺ T cells and tumor cell apoptosis were widespread and varied among the viruses. Antitumor activity of virus VV-A34, bearing amino acid substitution A34^K151E to increase viral spreading, and virus VV-IL2v, expressing a mouse IL2 variant (mIL2v) with attenuated IL2 receptor alpha subunit binding, was similar to control virus VV-GFP. However, antitumor activity was significantly greater after virus VV-A34/IL2v, which expressed mIL2v together with A34^K151E mutation and viral B18R gene deletion, and virus VV-GMCSF that expressed mouse GM-CSF. Both viruses greatly increased expression of CD8 antigens Cd8a/Cd8b1 and cytotoxicity genes granzyme A, granzyme B, Fas ligand, and perforin-1 in tumors. VV-A34/IL2v led to higher serum IL2 and greater tumor expression of death receptor ligand TRAIL, but VV-GMCSF led to higher serum GM-CSF, greater expression of leukocyte chemokines and adhesion molecules, and more neutrophil recruitment. Together, the results show that antitumor activity is similarly increased by viral expression of GM-CSF or IL2v combined with additional genetic modifications.

TRIM65 E3 ligase targets VCAM-1 degradation to limit LPS-induced lung inflammation

Although the adhesion molecules-mediated leukocyte adherence and infiltration into tissues is an important step of inflammation, the post-translational regulation of these proteins on the endothelial cells is poorly understood. Here, we report that TRIM65, an ubiquitin E3 ligase of tripartite protein family, selectively targets vascular cell adhesion molecule 1 (VCAM-1) and promotes its ubiquitination and degradation, by which it critically controls the duration and magnitude of sepsis-induced pulmonary inflammation. TRIM65 is constitutively expressed in human vascular endothelial cells. During TNFα-induced endothelial activation, the protein levels of TRIM65 and VCAM-1 are inversely correlated. Expression of wild-type TRIM65, but not expression of a TRIM65 mutant that lacks E3 ubiquitin ligase function in endothelial cells, promotes VCAM-1 ubiquitination and degradation, whereas small interference RNA-mediated knockdown of TRIM65 attenuates VCAM-1 protein degradation. Further experiments show that TRIM65 directly interacts with VCAM-1 protein and directs its polyubiquitination, by which TRIM65 controls monocyte adherence and infiltration into tissues during inflammation. Importantly, TRIM65-deficient mice are more sensitive to lipopolysaccharide-induced death, due to sustained and severe pulmonary inflammation. Taken together, our studies suggest that TRIM65-mediated degradation of VCAM-1 represents a potential mechanism that controls the duration and magnitude of inflammation.

Effects from the induction of heat shock proteins in a murine model due to progression of aortic atherosclerosis

Heat shock proteins (HSPs) are molecular chaperones that repair denatured proteins. The relationship between HSPs and various diseases has been extensively studied. However, the relationship between HSPs and atherosclerosis remains unclear. In this study, we induced the expression of HSPs and analyzed the effects on the development/progression of atherosclerosis in vivo. Remarkably, when HSPs were induced in apolipoprotein E deficient (ApoE^-/-) mice prior to the formation of atheromas, the progression of atherosclerosis was inhibited; the short-term induction of HSPs significantly decreased the mRNA expression of intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) in the aorta. In contrast, the induction of HSPs after the formation of atheromas promoted the progression of atherosclerosis. In fact, the short-term induction of HSPs, after the formation of atheromas, significantly increased the mRNA expression of tumor necrosis factor-alpha, and interleukin 6 in the aorta. Of note, the induction of HSPs also promoted the formation of macrophage-derived foam cells. Overall, these results indicate that HSPs exerts different effects in the context of aortic atherosclerosis, depending on its degree of progression. Therefore, the induction and inhibition of HSPs should be considered for the prevention and treatment of atherosclerosis, respectively.

Endothelial Rap1 (Ras-Association Proximate 1) Restricts Inflammatory Signaling to Protect From the Progression of Atherosclerosis

OBJECTIVE

Small GTPase Rap1 (Ras-association proximate 1) is a novel, positive regulator of NO release and endothelial function with a potentially key role in mechanosensing of atheroprotective, laminar flow. Our objective was to delineate the role of Rap1 in the progression of atherosclerosis and its specific functions in the presence and absence of laminar flow, to better define its role in endothelial mechanisms contributing to plaque formation and atherogenesis. Approach and Results: In a mouse atherosclerosis model, endothelial Rap1B deletion exacerbates atherosclerotic plaque formation. In the thoracic aorta, where laminar shear stress-induced NO is otherwise atheroprotective, plaque area is increased in Athero-Rap1BiΔEC (atherogenic endothelial cell-specific, tamoxifen-inducible Rap1A+Rap1B knockout) mice. Endothelial Rap1 deficiency also leads to increased plaque size, leukocyte accumulation, and increased CAM (cell adhesion molecule) expression in atheroprone areas, whereas vascular permeability is unchanged. In endothelial cells, in the absence of protective laminar flow, Rap1 deficiency leads to an increased proinflammatory TNF-α (tumor necrosis factor alpha) signaling and increased NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activation and elevated inflammatory receptor expression. Interestingly, this increased signaling to NF-κB activation is corrected by AKTVIII-an inhibitor of Akt (protein kinase B) translocation to the membrane. Together, these data implicate Rap1 in restricting Akt-dependent signaling, preventing excessive cytokine receptor signaling and proinflammatory NF-κB activation.

CONCLUSIONS

Via 2 distinct mechanisms, endothelial Rap1 protects from the atherosclerosis progression in the presence and absence of laminar flow; Rap1-stimulated NO release predominates in laminar flow, and restriction of proinflammatory signaling predominates in the absence of laminar flow. Our studies provide novel insights into the mechanisms underlying endothelial homeostasis and reveal the importance of Rap1 signaling in cardiovascular disease.

Bazedoxifene Plays a Protective Role against Inflammatory Injury of Endothelial Cells by Targeting CD40

The inflammatory response and oxidative stress play key roles in the formation and development of atherosclerosis. Bazedoxifene is a new IL6/GP130 inhibitor recommended by the FDA for clinical use as a selective estrogen receptor modulator. However, its role in cardiovascular diseases has been poorly studied. In our study, we explored the mechanism of bazedoxifene's protective effect against inflammatory injury of vascular endothelial cells (VECs) stimulated by TNF-α. Various methods were used to verify the effect of bazedoxifene on VECs, including a cell viability assay, a wound healing assay, immunofluorescence staining, and western blotting. Our results showed that TNF-α could induce inflammatory damage to VECs, which manifested as upregulated expression of CD40, increased production of ROS, enhanced adhesion of THP-1 cells to VECs, and impaired viability and migration of VECs, while bazedoxifene could significantly reduce the endothelial damage caused by TNF-α. In addition, we found that an siRNA targeting CD40 dramatically alleviated the VEC damage induced by TNF-α. Therefore, we explored the potential relationship between bazedoxifene and CD40. Our data suggest that bazedoxifene has a protective effect against VEC damage induced by TNF-α and that its underlying mechanism may be related to the regulation of CD40.

High Endothelial Venules Accelerate Naive T Cell Recruitment by Tumor Necrosis Factor-Mediated R-Ras Upregulation

Recruitment of naive T cells to lymph nodes is essential for the development of adaptive immunity. Upon pathogen infection, lymph nodes promptly increase the influx of naive T cells from the circulation in order to screen and prime the T cells. The precise contribution of the lymph node vasculature to the regulation of this process remains unclear. Here we show a role for the Ras GTPase, R-Ras, in the functional adaptation of high endothelial venules to increase naive T cell trafficking to the lymph nodes. R-Ras is transiently up-regulated in the endothelium of high endothelial venules by the inflammatory cytokine tumor necrosis factor (TNF) within 24 hours of pathogen inoculation. TNF induces R-Ras upregulation in endothelial cells via JNK and p38 mitogen-activated protein kinase but not NF-κB. Studies of T cell trafficking found that the loss of function of endothelial R-Ras impairs the rapid acceleration of naive T cell recruitment to the lymph nodes upon inflammation. This defect diminished the ability of naive OT-1 T cells to develop antitumor activity against ovalbumin-expressing melanoma. Proteomic analyses suggest that endothelial R-Ras facilitates TNF-dependent transendothelial migration (diapedesis) of naive T cells by modulating molecular assembly the at T cell-endothelial cell interface. These findings give new mechanistic insights into the functional adaptation of high endothelial venules to accelerate naive T cell recruitment to the lymph nodes.

Pathophysiological landscape of osteoarthritis

A sharp rise in osteoarthritis (OA) incidence is expected as over 25% of world population ages in the coming decade. Although OA is considered a degenerative disease, mounting evidence suggests a strong connection with chronic metabolic conditions and low-grade inflammation. OA pathology is increasingly understood as a complex interplay of multiple pathological events including oxidative stress, synovitis and immune responses revealing its intricate nature. Cellular, biochemical and molecular aspects of these pathological events along with major outcomes of the relevant research studies in this area are discussed in the present review. With reference to their published and unpublished work, the authors strongly propose synovitis as a central OA pathology and the key OA pathological events are described in connection with it. Recent research outcomes also have succeeded to establish a linkage between metabolic syndrome and OA, which has been precisely included in the present review. Impact of aging process cannot be neglected in OA. Cell senescence is an important mechanism of aging through which it facilitates development of OA like other degenerative disorders, also discussed within a frame of OA. Conclusively, the reviewers urge low-grade inflammation linked to aging and derailed immune function as a pathological platform for OA development and progression. Thus, interventions targeted to prevent inflammaging hold a promising potential in effective OA management and efforts should be invested in this direction.

Roseltide rT7 is a disulfide-rich, anionic, and cell-penetrating peptide that inhibits proteasomal degradation

Disulfide-rich plant peptides with molecular masses of 2-6 kDa represent an expanding class of peptidyl-type natural products with diverse functions. They are structurally compact, hyperstable, and underexplored as cell-penetrating agents that inhibit intracellular functions. Here, we report the discovery of an anionic, 34-residue peptide, the disulfide-rich roseltide rT7 from Hibiscus sabdariffa (of the Malvaceae family) that penetrates cells and inhibits their proteasomal activities. Combined proteomics and NMR spectroscopy revealed that roseltide rT7 is a cystine-knotted, six-cysteine hevein-like cysteine-rich peptide. A pair-wise comparison indicated that roseltide rT7 is >100-fold more stable against protease degradation than its S-alkylated analog. Confocal microscopy studies and cell-based assays disclosed that after roseltide rT7 penetrates cells, it causes accumulation of ubiquitinated proteins, inhibits human 20S proteasomes, reduces tumor necrosis factor-induced IκBα degradation, and decreases expression levels of intercellular adhesion molecule-1. Structure-activity studies revealed that roseltide rT7 uses a canonical substrate-binding mechanism for proteasomal inhibition enabled by an IIML motif embedded in its proline-rich and exceptionally long intercysteine loop 4. Taken together, our results provide mechanistic insights into a novel disulfide-rich, anionic, and cell-penetrating peptide, representing a potential lead for further development as a proteasomal inhibitor in anti-cancer or anti-inflammatory therapies.

MicroRNA-29a-3p Reduces TNFα-Induced Endothelial Dysfunction by Targeting Tumor Necrosis Factor Receptor 1

miR-29a-3p has been shown to be associated with cardiovascular diseases; however, the effect of miR-29a-3p on endothelial dysfunction is unclear. This study aimed to reveal the effects and mechanisms of miR-29a-3p on endothelial dysfunction. The levels of vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), and E-selectin were determined by real-time PCR and immunofluorescence staining to reveal the degree of tumor necrosis factor alpha (TNFα)-induced endothelial dysfunction. A luciferase activity assay and cell transfection with a miR-29a-3p mimic or an inhibitor were used to reveal the underlying mechanisms of miR-29a-3p action. Furthermore, the effects of miR-29a-3p on endothelial dysfunction were assessed in C57BL/6 mice injected with TNFα and/or a miR-29a-3p agomir. The results showed that the expression of TNFα-induced adhesion molecules in vascular endothelial cells (EA.hy926 cells, human aortic endothelial cells [HAECs], and primary human umbilical vein endothelial cells [pHUVECs]) and smooth muscle cells (human umbilical vein smooth muscle cells [HUVSMCs]) was significantly decreased following transfection with miR-29a-3p. This effect was reversed by cotransfection with a miR-29a-3p inhibitor. As a key target of miR-29a-3p, tumor necrosis factor receptor 1 mediated the effect of miR-29a-3p. Moreover, miR-29a-3p decreased the plasma levels of TNFα-induced VCAM-1 (32.62%), ICAM-1 (38.22%), and E-selectin (39.32%) in vivo. These data indicate that miR-29a-3p plays a protective role in TNFα-induced endothelial dysfunction, suggesting that miR-29a-3p is a novel target for the prevention and treatment of atherosclerosis.

Salidroside prevents tumor necrosis factor-α-induced vascular inflammation by blocking mitogen-activated protein kinase and NF-κB signaling activation

Vascular inflammation is a key factor in the pathogenesis of atherosclerosis. Salidroside is an important active ingredient extracted from the root of the Rhodiola rosea plant, which has been reported to have antioxidative, anti-cancer, neuroprotective and cardioprotective effects. However, the effects of salidroside on vascular inflammation have not been clarified. The purpose of the present study was to investigate the protective effects of salidroside against tumor necrosis factor (TNF)-α-induced vascular inflammation in cardiac microvascular endothelial cells (CMECs), a specific cell type derived from coronary micro-vessels. Over a 24-h period, salidroside did not exert any significant cytotoxicity up to a dose of 100 µM. Additionally, salidroside decreased the expression levels of the cell adhesion molecule vascular cell adhesion molecule-1 (VCAM-1) in TNF-α-stimulated CMECs, thus suppressing monocyte-to-CMEC adhesion. Salidroside also decreased the production of inflammatory cytokines such as interleukin (IL)-1β, IL-6 and monocyte chemotactic protein 1 (MCP-1) in TNF-α-induced CMECs, as well as suppressing TNF-α-activated mitogen-activated protein kinase (MAPK) and NF-κB activation. Since MAPKs and NF-κB both serve notable roles in regulating the expression of VCAM-1, IL-1β, IL-6 and MCP-1, the present study provided a preliminary understanding of the mechanism underlying the protective effects of salidroside. Overall, salidroside alleviated vascular inflammation by mediating MAPK and NF-κB activation in TNF-α-induced CMECs. These results indicated that salidroside may have potential applications as a therapeutic agent against vascular inflammation and atherosclerosis.

Tumor necrosis factor alpha (TNF-α) and its soluble receptors are associated with disability, disability progression and clinical forms of multiple sclerosis

BACKGROUND

The association between tumor necrosis factor (TNF)-α, soluble TNF receptor (sTNFR)1 and sTNFR2 with clinical characteristics of multiple sclerosis (MS) remains unclear.

OBJECTIVE

To examine whether TNF-α, sTNFR1 and sTNFR2 are associated with MS diagnosis, disability, disability progression and clinical forms of MS.

MATERIALS AND SUBJECTS

The study included 147 patients with relapsing-remitting MS (RRMS), 21 with progressive clinical forms (ProgMS) and 70 controls. Expanded Disability Status Scale (EDSS) evaluated disability as mild (EDSS < 3.0) or moderate/high (EDSS ≥ 3.0). Multiple Sclerosis Severity Score (MSSS) evaluated disability progression as no progression (MSSS < 5) and progression (MSSS ≥ 5). Baseline data of subjects and plasma levels of TNF-α, sTNFR1, sTNFR2 were obtained.

RESULTS

The MS diagnosis explained 44.6% and 12.3% of TNF-α and sTNFR2 levels, respectively. Moderate/high disability and disability progression were best predicted by sTNFR1 and age (positively) and ProgMS were best predicted by sTNFR1 (positively) and sTNFR2 (negatively), coupled with age and sex. A composite score reflecting the sTNFR1/sTNFR2 ratio showed a positive association with ProgMS after adjusting for age and sex.

CONCLUSION

Increased sTNFR1 and age were positively associated with disability and disability progression, whereas increased sTNFR1 (positively) and sTNFR2 (negatively) were associated with ProgMS, suggesting a distinct role of them in the immunopathological mechanisms of MS.

Exosomes Derived From Low-Intensity Pulsed Ultrasound-Treated Dendritic Cells Suppress Tumor Necrosis Factor-Induced Endothelial Inflammation

OBJECTIVES

Endothelial cell inflammation plays an important role in atherosclerosis. Low-intensity pulsed ultrasonography (LIPUS) exerts an anti-inflammatory function on endothelial cells, whereas the underlying mechanism has not been fully elucidated.

METHODS

Bone marrow dendritic cells (BMDCs) derived from bone barrow cells were treated with LIPUS, and exosomes secreted into the supernatant were purified. The isolated exosomes were incubated with human umbilical vein endothelial cells (HUVECs) to investigate their effect on tumor necrosis factor (TNF)-α-induced endothelial inflammation. Ultrastructure was analyzed by transmission electron microscopy. Messenger RNA levels were determined by quantitative reverse transcription polymerase chain reaction, and protein levels were analyzed by western blot.

RESULTS

The isolated exosomes presented a typical exosomal size of 30 to 100 nm in diameter and expressed exosome positive markers (Alix, CD63, and TSG101) but not the exosome negative marker (Calnexin). Exosomes derived from LIPUS-treated BMDCs were rich in miR-16 and miR-21, which could be engulfed by HUVECs. Pretreatment with exosomes impeded TNFα-induced HUVEC activation and downregulated TNFα-stimulated expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1, thus preventing TNFα-induced activation of the nuclear factor-κB signaling pathway.

CONCLUSION

Exosomes derived from LIPUS-treated BMDC inhibit TNFα-induced endothelial inflammation by inhibiting the nuclear factor-κB signaling pathway.

Vx-11e protects against titanium-particle-induced osteolysis and osteoclastogenesis by supressing ERK activity

Wear particle-induced osteolysis around the prosthesis is the most common long-term complication after total joint replacement surgery which often leads to aseptic loosening of the prosthesis. Osteoclasts play key roles in the osteolytic process. Currently there is a lack of clinically effective measures to prevent or treat peri-prosthetic osteolysis and thus identification of new agents that can inhibit the enhanced osteoclastic bone resorption is warranted. Through this study, we discovered that the specific and potent ERK1/2 inhibitor, Vx-11e, can protect against calvarial osteolysis caused by titanium (Ti) particles in vivo. Low doses of Vx-11e mildly reduced osteoclast resorption whilst no calvarial osteolysis was observed with high dose Vx-11e treatment. Histological examination showed fewer osteoclasts and reduced bone erosion in the Vx-11e treated groups. In vitro cellular analyses showed that Vx-11e inhibited osteoclast formation from BMM precursors in response to RANKL, as well as bone resorption by mature osteoclasts. Mechanistically, Vx-11e impaired RANKL-induced ERK1/2 signaling by inhibiting its kinase activity thereby blocking the phosphorylation of downstream substrates. Moreover, Vx-11e significantly reduced the expression of RANKL-mediated genes such as ACP5/TRAcP, CTR, MMP-9, CTSK. Collectively, our data provides evidence for the potential therapeutic use of Vx-11e for the treatment of osteolysis diseases caused by extremely actived osteoclastogenesis.

Label-Free Multi Parameter Optical Interrogation of Endothelial Activation in Single Cells using a Lab on a Disc Platform

Cellular activation and inflammation leading to endothelial dysfunction is associated with cardiovascular disease (CVD). We investigated whether a single cell label-free multi parameter optical interrogation system can detect endothelial cell and endothelial progenitor cell (EPC) activation in vitro and ex vivo, respectively. Cultured human endothelial cells were exposed to increasing concentrations of tumour necrosis factor alpha (TNF-α) or lipopolysaccharide (LPS) before endothelial activation was validated using fluorescence-activated cell sorting (FACS) analysis of inflammatory marker expression (PECAM-1, E-selectin and ICAM-1). A centrifugal microfluidic system and V-cup array was used to capture individual cells before optical measurement of light scattering, immunocytofluorescence, auto-fluorescence (AF) and cell morphology was determined. In vitro, TNF-α promoted specific changes to the refractive index and cell morphology of individual cells concomitant with enhanced photon activity of fluorescently labelled inflammatory markers and increased auto-fluorescence (AF) intensity at three different wavelengths, an effect blocked by inhibition of downstream signalling with Iκβ. Ex vivo, there was a significant increase in EPC number and AF intensity of individual EPCs from CVD patients concomitant with enhanced PECAM-1 expression when compared to normal controls. This novel label-free 'lab on a disc' (LoaD) platform can successfully detect endothelial activation in response to inflammatory stimuli in vitro and ex vivo.

Role of Serum miR-181b, Proinflammatory Cytokine, and Adhesion Molecules in Behçet's Disease

Behçet's disease (BD) is a chronic multi-systemic inflammatory disease of uncertain pathogenesis and with no definitive diagnostic test. The aims of this study were to investigate serum levels of miR-181b in BD patients and to correlate this candidate biomarker with disease activity, cytokines, and adhesion molecules to identify new markers that can be used as a diagnostic tool for BD. Blood samples were collected from 96 participants who were classified according to their BD current activity form into 3 groups: healthy control, active BD, and inactive BD patients. MiR-181b was estimated by real-time polymerase chain reaction. However, high sensitive C-reactive protein (hs-CRP), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), E-selectin, and vascular cell adhesion molecule 1 (VCAM-1) levels were determined by enzyme-linked immunosorbent assay. Serum levels of miR-181b, hs-CRP, TNF-α, IL-6, E-selectin, and VCAM-1 were significantly higher in patients than in controls, but no significant difference was observed between the active and inactive BD groups. IL-6 was positively correlated with adhesion molecules, E-selectin, and VCAM-1. MiR-181b was positively correlated with hs-CRP, TNF-α, IL-6, and VCAM-1 in all subjects. In conclusion, miR-181b could play an important role in BD pathophysiology. MiR-181b could be utilized as potential biomarker for diagnosis and therapeutic targeting of BD. However, further studies with larger patient number are required to support these findings.

Inflammatory adipocyte-derived extracellular vesicles promote leukocyte attachment to vascular endothelial cells

BACKGROUND AND AIMS

Obesity is associated with an increased risk of cardiovascular disease, but the mechanisms involved are not completely understood. In obesity, the adipocyte microenvironment is characterised by both hypoxia and inflammation. Therefore, we sought to determine whether extracellular vesicles (EVs) derived from adipocytes in this setting might be involved in mediating cardiovascular disease, specifically by promoting leukocyte attachment to vascular endothelial cells.

METHODS

Mature 3T3-L1 adipocytes were incubated for 24 h under control, TNF-α (30 ng/mL), hypoxia (1% O₂), or TNF-α+hypoxia (30 ng/mL, 1% O₂) conditions. EVs were isolated by differential ultracentrifugation and analysed by nanoparticle tracking analysis. Primary human umbilical vein endothelial cells (HUVECs) were treated with EVs for 6 h before being lysed for Western blotting to investigate changes in adhesion molecule production, or for use in leukocyte attachment assays.

RESULTS

EVs from adipocytes treated with TNF-α and TNF-α+hypoxia increased vascular cell adhesion molecule (VCAM-1) production in HUVECs compared to basal level (4.2 ± 0.6 and 3.8 ± 0.3-fold increase, respectively (p < 0.05)), an effect that was inhibited by an anti-TNF-α neutralising antibody. Production of other adhesion molecules (E-selectin, P-selectin, platelet endothelial cell adhesion molecule and VE-Cadherin) was unchanged. Pre-incubating HUVECs with TNF-α+hypoxia EVs significantly increased leukocyte attachment compared to basal level (3.0 ± 0.4-fold increase (p < 0.05)).

CONCLUSIONS

Inflammatory adipocyte EVs induce VCAM-1 production in vascular endothelial cells, accompanied by enhanced leukocyte attachment. Preventing adipocyte derived EV-induced VCAM-1 upregulation may offer a novel therapeutic target in the prevention of obesity-driven cardiovascular disease.

Anti-GRP78 autoantibodies induce endothelial cell activation and accelerate the development of atherosclerotic lesions

The 78-kDa glucose-regulated protein (GRP78) is an ER molecular chaperone that aids in protein folding and secretion. However, pathological conditions that cause ER stress can promote the relocalization of GRP78 to the cell surface (csGRP78), where it acts as a signaling receptor to promote cancer progression. csGRP78 also possesses antigenic properties, leading to the production of anti-GRP78 autoantibodies, which contribute to tumor growth. In contrast, the presence and role of anti-GRP78 autoantibodies in atherosclerosis is unknown. Here, we show that atherosclerotic-prone ApoE-/- mice develop circulating anti-GRP78 autoantibodies that bind to csGRP78 on lesion-resident endothelial cells. Moreover, GRP78-immunized ApoE-/- mice exhibit a marked increase in circulating anti-GRP78 autoantibody titers that correlated with accelerated lesion growth. Mechanistically, engagement of anti-GRP78 autoantibodies with csGRP78 on human endothelial cells activated NF-κB, thereby inducing the expression of ICAM-1 and VCAM-1, a process blocked by NF-κB inhibitors. Disrupting the autoantibody/csGRP78 complex with enoxaparin, a low-molecular-weight heparin, reduced the expression of adhesion molecules and attenuated lesion growth. In conclusion, anti-GRP78 autoantibodies play a crucial role in atherosclerosis development, and disruption of the interaction between anti-GRP78 autoantibodies and csGRP78 represents a therapeutic strategy.

Krüppel-like factor 14, a coronary artery disease associated transcription factor, inhibits endothelial inflammation via NF-κB signaling pathway

BACKGROUND AND AIMS

Human genetic studies indicated that variations near the transcription factor Krüppel-like factor 14 (KLF14) gene locus are highly associated with coronary artery disease. Activation of endothelial cells (ECs) by pro-inflammatory molecules and pathways is a primary step in atherosclerosis development. We aimed to investigate the effects and mechanism of KLF14 on inflammatory responses in ECs.

METHODS

Adenovirus-mediated overexpression of human KLF14 and EC specific Klf14 knockout mice were applied to study the role of KLF14 in EC inflammation. Intravital microscopy was used to examine leukocyte-endothelial cell interactions in vivo.

RESULTS

The expression of Klf14 was markedly decreased in mouse aortic ECs in both acute and chronic inflammatory conditions. Overexpression of KLF14 inhibited inflammatory activation of human ECs stimulated by interleukin 1β and tumor necrosis factor α. Primary pulmonary ECs from Klf14 knockout mice showed increased expression of adhesion molecules under IL-1β stimuli. Mechanistically, KLF14 inhibited NF-κB signaling pathway by transcriptionally suppressing the expression of p65, resulting in significantly decreased leukocyte adhesion to activated ECs. Using intravital microscopy, an increased leukocyte-endothelial cell interaction was observed in endothelial specific Klf14 knockout mice compared to wild type control mice. Additionally, perhexiline, a KLF14 activator, induces KLF14 expression in ECs and reduced leukocyte-endothelial cell interactions in vitro and in vivo.

CONCLUSIONS

The data revealed that KLF14 inhibited the inflammatory response in ECs and the protective effects were mediated by transcriptional inhibition of NF-κB signaling pathway. Endothelial KLF14 could be a potential therapeutic target for cardiovascular diseases.

LPA4-Mediated Vascular Network Formation Increases the Efficacy of Anti-PD-1 Therapy against Brain Tumors

: The structure and function of tumor blood vessels profoundly affects the tumor microenvironment. Signals mediated through the lysophosphatidic acid receptor 4 (LPA4) promote vascular network formation to restore normal vascular barrier function in subcutaneous tumors and thus improve drug delivery. However, the characteristics of the vasculature vary by organ and tumor types, and how drug delivery and leukocyte trafficking are affected by modification of vascular function by LPA in different cancers is unclear. Here, we show that LPA4 activation promotes the formation of fine vascular structures in brain tumors. RhoA/ROCK signaling contributed to LPA-induced endothelial cell-cell adhesion, and RhoA/ROCK activity following LPA4 stimulation regulated expression of VCAM-1. This resulted in increased lymphocyte infiltration into the tumor. LPA improved delivery of exogenous IgG into brain tumors and enhanced the anticancer effect of anti-programmed cell death-1 antibody therapy. These results indicate the effects of LPA on vascular structure and function apply not only to chemotherapy but also to immunotherapy. SIGNIFICANCE: These findings demonstrate that lysophosphatidic acid, a lipid mediator, promotes development of a fine capillary network in brain tumors by inducing tightening of endothelial cell-to-cell adhesion, facilitating improved drug delivery, and lymphocyte penetration.

Attenuation of antimalarial agent hydroxychloroquine on TNF-α-induced endothelial inflammation

OBJECTIVE

Hydroxychloroquine (HCQ) is an antimalarial drug that is widely used in the treatment of some autoimmune diseases. In the present study, we explore the role of HCQ in regulating endothelial inflammation and its underlying mechanism.

METHODS

Human umbilical vein endothelial cells (HUVECs) were isolated from fresh umbilical cords. Protein expression was measured by Western blot or immunofluorescence staining. Endothelial adhesion ability was determined by leukocyte-endothelial monolayer adhesion assay. Transwell assay was used to measure the transendothelial-migration of PBMCs.

RESULTS

TNF-α-induced endothelial-leukocyte adhesion and the leukocyte transmigration were profoundly reduced by HCQ treatment. HCQ treatment dramatically inhibited the expression of TNF-α-induced endothelial ICAM-1 and VCAM-1. Furthermore, treatment with HCQ prevented the TNF-α-induced translocation of NF-κB p65 into the nucleus and the phosphorylation of the p65 subunit in HUVECs. HCQ inhibited the expression of phosphorylated p38 and JNK protein but not ERK. Treatment with NF-κB, p38 and JNK inhibitor could also reduce TNF-α-induced endothelial-leukocyte adhesion and the endothelial expression of ICAM-1 and VCAM-1. HCQ administration also suppressed TNF-α induced lung injury in mice by reducing neutrophil infiltration in pulmonary interstitial tissue.

CONCLUSIONS

This work shows the inhibitory effect of HCQ on endothelial inflammatory response through, at least in part, blocking NF-κB, p38 and JNK pathways. Our findings suggest that HCQ may be a promising approach for the treatment of inflammatory vascular disease beyond its immunomodulatory actions.

Protective effect of KLF15 on vascular endothelial dysfunction induced by TNF‑α

Atherosclerosis (AS) is a cardiovascular disease with a relatively high incidence rate. Krüppel-like factor 15 (KLF15) has a role in numerous pathological processes, including nephropathy, abnormal glucose metabolism and myocardial injury. The aim of the present study was to investigate the function of KLF15 in vascular endothelial dysfunction. MTT analyses, nitric oxide (NO) detection and cell adhesion detection kits were used to investigate the viability and adhesion of, and quantity of NO released by Eahy926 cells induced by tumor necrosis factor (TNF)-α, respectively. Reverse transcription-quantitative polymerase chain reaction and western blot analyses were performed to determine the expression levels of KLF15, endothelial nitric oxide synthase, monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), transforming growth factor-β1 (TGF-β1), phosphorylated (p-)transcription factor p65 (p65) and nuclear factor erythroid 2-related factor 2 (Nrf2). The results of the present study demonstrated that TNF-α was able to induce vascular endothelial dysfunction in Eahy926 cells at an optimum concentration of 10 ng/ml. Overexpression of KLF15 markedly enhanced cell viability in addition to the quantity of released NO of TNF-α-induced Eahy926 cells, and increased the expression levels of eNOS and Nrf2. Furthermore, overexpression of KLF15 markedly suppressed the rate of cellular adhesion, and downregulated levels of MCP-1, ICAM-1, TGF-β1 and p-p65 in TNF-α induced Eahy926 cells. In conclusion, the results of the present study suggested that overexpression of KLF15 in Eahy926 cells exhibited a protective effect against TNF-α induced dysfunction via activation of Nrf2 signaling and inhibition of nuclear factor κB signaling.

Chemokines cooperate with TNF to provide protective anti-viral immunity and to enhance inflammation

The role of cytokines and chemokines in anti-viral defense has been demonstrated, but their relative contribution to protective anti-viral responses in vivo is not fully understood. Cytokine response modifier D (CrmD) is a secreted receptor for TNF and lymphotoxin containing the smallpox virus-encoded chemokine receptor (SECRET) domain and is expressed by ectromelia virus, the causative agent of the smallpox-like disease mousepox. Here we show that CrmD is an essential virulence factor that controls natural killer cell activation and allows progression of fatal mousepox, and demonstrate that both SECRET and TNF binding domains are required for full CrmD activity. Vaccination with recombinant CrmD protects animals from lethal mousepox. These results indicate that a specific set of chemokines enhance the inflammatory and protective anti-viral responses mediated by TNF and lymphotoxin, and illustrate how viruses optimize anti-TNF strategies with the addition of a chemokine binding domain as soluble decoy receptors.

The beclomethasone anti-inflammatory effect occurs in cell/mediator-dependent manner and is additively enhanced by formoterol: NFkB, p38, PKA analysis

AIMS

Beclomethasone/formoterol (BDP/FOR) has been reported to be more effective than its separate components in airway disease control and in airway inflammation improvement. However, BDP/FOR effects on cytokine-induced inflammation in structural cells have not been described and whether these effects occur in a cell- and mediator-dependent manner has not been fully elucidated. We sought to evaluate BDP and/or FOR effects on endothelial ICAM-1, E-selectin, IL-8 and on bronchial epithelial ICAM-1 and IL-8. Specific intracellular signaling pathways were also investigated.

MATERIALS AND METHODS

Surface adhesion molecule expression and IL-8 release induced by TNF-alpha were measured by ELISA. Intracellular signaling pathways were investigated by a) EMSA and Western blot analysis to evaluate NF-κB DNA-binding and MAPK-p38 phosphorylation; b) PDTC/SB203580 as NF-κB/p38 inhibitors; c) forskolin/H-89 as PKA activator/inhibitor.

KEY FINDINGS

BDP/FOR additively reduced endothelial E-selectin and IL-8 as well as bronchial epithelial ICAM-1 and IL-8. BDP/FOR and SB203580 showed the highest inhibitory effect on epithelial IL-8, whereas endothelial ICAM-1 was never affected by BDP/FOR and PDTC. TNF-alpha-induced NF-κB DNA-binding and MAPK-p38 phosphorylation were not influenced by BDP/FOR. Forskolin mimicked FOR effects; H-89 partially reversed the BDP/FOR inhibition in a mediator-dependent manner.

SIGNIFICANCE

The BDP/FOR inhibition degree was related to the inflammatory mediator- and cell-type considered. FOR additively enhanced BDP effects by partially involving both dependent- and independent-PKA mechanisms. Our results might contribute to highlight the strong relationship between specific molecular pathways and different sensitivity to the corticosteroid/β2-agonist effects and to clarify the molecular mechanisms underlying the BDP/FOR anti-inflammatory activity in vivo.

Dual specificity phosphatase DUSP6 promotes endothelial inflammation through inducible expression of ICAM-1

Tumor necrosis factor (TNF)-α activates a diverse array of signaling pathways in vascular endothelial cells (ECs), leading to the inflammatory phenotype that contributes to the vascular dysfunction and neutrophil emigration in patients with sepsis. To date, it is not well understood what key regulator might coordinate signaling pathways to achieve inflammatory response in TNF-α-stimulated ECs. This study investigated the role of dual specificity phosphatase-6 (DUSP6) in the regulation of endothelial inflammation. Using knockout mice, we found that DUSP6 is important for TNF-α-induced endothelial intercellular adhesion molecule-1 (ICAM-1) expression in aorta and in vein. Moreover, genetic deletion of Dusp6 in pulmonary circulation significantly alleviated the susceptibility of mice to lung injury caused by neutrophil recruitment during experimental sepsis induced by TNF-α or lipopolysaccharide (LPS). The role of DUSP6 was further investigated in primary human umbilical vein endothelial cells (HUVECs). Employing RNAi approach in which endogenous DUSP6 was ablated, we showed a critical function of DUSP6 to facilitate TNF-α-induced ICAM-1 expression and endothelial leukocyte interaction. Interestingly, DUSP6-promoted endothelial inflammation is independent of extracellular signaling-regulated kinase (ERK) signaling. On the other hand, inducible DUSP6 leads to activation of canonical nuclear factor (NF)-κB-mediated transcription of ICAM-1 gene in TNF-α-stimulated human ECs. These results are the first to demonstrate a positive role of DUSP6 in endothelial inflammation-mediated pathological process and the underlying mechanism through which DUSP6 promotes NF-κB signaling in the inflamed ECs. Our findings suggest that manipulation of DUSP6 holds great potential for the treatment of acute inflammatory diseases.

Role of tumour necrosis factor receptor-1 and nuclear factor-κB in production of TNF-α-induced pro-inflammatory microparticles in endothelial cells

Tumour necrosis factor-α (TNF-α) is upregulated in many inflammatory diseases and is also a potent agent for microparticle (MP) generation. Here, we describe an essential role of TNF-α in the production of endothelial cell-derived microparticles (EMPs) in vivo and the function of TNF-α-induced EMPs in endothelial cells. We found that TNF-α rapidly increased blood levels of EMPs in mice. Treatment of human umbilical vein endothelial cells (HUVECs) with TNF-α also induced EMP formation in a time-dependent manner. Silencing of TNF receptor (TNFR)-1 or inhibition of the nuclear factor-κB (NF-κB) in HUVECs impaired the production of TNF-α-induced EMP. Incubation of HUVECs with PKH-67-stained EMPs showed that endothelial cells readily engulfed EMPs, and the engulfed TNF-α-induced EMPs promoted the expression of pro-apoptotic molecules and upregulated intercellular adhesion molecule-1 level on the cell surface, which led to monocyte adhesion. Collectively, our findings indicate that the generation of TNF-α-induced EMPs was mediated by TNFR1 or NF-κB and that EMPs can contribute to apoptosis and inflammation of endothelial cells.

Quinic acid inhibits vascular inflammation in TNF-α-stimulated vascular smooth muscle cells

Atherosclerosis is a chronic inflammatory disease, and the increased expression of adhesion molecules on vascular smooth muscle cells contributes to the progression of vascular disease. Quinic acid (QA) has been shown to possess radioprotection, anti-neuroinflammatory, and anti-oxidant activities; however, an anti-vascular inflammatory effect has not been reported. This study investigated the effect of QA on the expression of vascular cell adhesion molecule-1 (VCAM-1) stimulated by TNF-α in MOVAS cells. Pre-incubation of MOVAS cells, the mouse vascular smooth muscle cell line for 2h with QA (0.1, 1 and 10 μg/mL) dose-dependently inhibits TNF-α-induced mRNA and protein expression of VCAM-1 and monocyte adhesion. QA inhibits TNF-α-stimulated phosphorylation of MAP kinase and NK-κB activation. Our results indicate that QA inhibits the TNF-α-stimulated induction of VCAM-1 in VSMC by inhibiting the MAP kinase and NF-κB signaling pathways and the adhesion capacity of VSMC, which may explain the ability of QA to inhibit vascular inflammation such as atherosclerosis.

Pretreatment Liver Injury Predicts Poor Prognosis of DLBCL Patients

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous group of lymphoma, with different clinical manifestation and prognosis. The International Prognostic Index (IPI), an index designed during the prerituximab era for aggressive lymphoma, showed variable values in the prediction of patient clinical outcomes. The aim of this study was to analyze the prognostic value and causes of pretreatment liver injury in 363 de novo DLBCL patients in our institution. Pretreatment liver impairment, commonly detected in lymphoma patients, showed significant association with poor outcomes and increased serum inflammatory cytokines in DLBCL patients but had no relation to hepatitis B virus replication nor lymphomatous hepatic infiltration. Multivariate analysis revealed that liver dysfunction, advanced Ann Arbor stage, and elevated lactate dehydrogenase (LDH) were independent adverse prognostic factors of both PFS and OS. Accordingly, a new liver-IPI prognostic model was designed by adding liver injury as an important factor in determining IPI score. Based on Kaplan-Meier curves for PFS and OS, the liver-IPI showed better stratification in DLBCL patients than either the IPI or the revised IPI in survival prediction.

iNOS-derived peroxynitrite mediates high glucose-induced inflammatory gene expression in vascular smooth muscle cells through promoting KLF5 expression and nitration

Inducible NO synthase (iNOS) expression and peroxynitrite formation are significantly increased in diabetic vascular tissues. Transcription factor KLF5 activates iNOS gene transcription and is involved in vascular inflammatory injury and remodeling. However, mutual regulation between KLF5, iNOS and peroxynitrite in diabetic vascular inflammation, as well as the underlying mechanisms, remain largely unknown. In this study, we found a marked increase in KLF5 and iNOS expression in vascular smooth muscle cells (VSMC) of diabetic patients. High glucose-induced expression of KLF5 and iNOS was also observed in cultured mouse VSMCs. Further investigation showed that high glucose induced KLF5 nitration by iNOS-mediated peroxynitrite generation, and nitrated KLF5 increased its interaction with NF-κB p50 and thus cooperatively activated the expression of inflammatory cytokines TNF-α and IL-1β. Furthermore, we showed that the VSMC-specific knockout of KLF5 dramatically reduced inflammatory cytokine expression in the vascular tissues of diabetic mice. Moreover, 17β-estradiol (E2) inhibited high glucose-mediated effects in VSMCs, and in the response to E2, estrogen receptor (ER) α competed with KLF5 for binding to NF-κB p50, which in turn leads to the suppression of inflammatory gene expression in VSMCs. Together, the present findings were the first to show that KLF5 expression and nitration by iNOS-mediated peroxynitrite are necessary for the induction of TNF-α and IL-1β expression in VSMCs of diabetic vascular tissues.

Schisandrin B inhibits LPS-induced inflammatory response in human umbilical vein endothelial cells by activating Nrf2

Schisandrin B (SchB), an active ingredient extracted from Schisandra chinensis (Turcz.) Baill, has been known to have anti-oxidant and anti-inflammatory activities. In this study, we investigated the anti-inflammatory effects and mechanism of SchB in LPS-stimulated human umbilical vein endothelial cells (HUVECs). The effects of SchB on VCAM-1, ICAM-1, NF-κB and Nrf2 expression were detected by western blot analysis. The effects of SchB on TNF-α and IL-8 production were detected by ELISA. The results showed that SchB strongly suppressed the production of TNF-α and IL-8 in HUVECs stimulated with LPS. SchB also inhibited LPS-induced VCAM-1 and ICAM-1 expression. Furthermore, SchB blocked the activation of NF-κB induced by LPS. In addition, SchB increased the expression of Nrf2 and HO-1 in a concentration-dependent manner. And the inhibition of TNF-α and IL-8 production by SchB was blocked by transfection with Nrf2 siRNA. Our findings showed that SchB inhibited LPS-induced inflammation in HUVECs by activating Nrf2 signaling pathway.

Characterisation of extracellular vesicle-subsets derived from brain endothelial cells and analysis of their protein cargo modulation after TNF exposure

Little is known about the composition and functional differences between extracellular vesicle (EV) subsets, such as microvesicles (MVs) and exosomes (EXOs), nor to what extent their cargo reflects the phenotypic state of the cell of origin. Brain endothelial cells are the constitutive part of the blood–brain barrier (BBB), a selective barrier that maintains brain homeostasis. BBB impairment is associated with several neuroinflammatory diseases with the pro-inflammatory cytokine tumour necrosis factor (TNF) often playing a key role. In the present study, shotgun proteomics and parallel reaction monitoring (PRM)-based targeted mass spectrometry were used to characterise brain endothelial cell-released EVs, and to study how TNF exposure modulated EV protein cargoes. MVs were found to be enriched in mitochondrial and cytoskeletal proteins, whereas EXOs were enriched in adhesion, histone and ribosomal proteins. After stimulation with TNF, several proteins involved in TNF and NF-κB signalling pathways, that were found to be differentially expressed in cells, were also differentially expressed in both MVs and EXOs. Thus, our results revealed some novel proteins as potentially useful candidates for discriminating between MVs and EXOs, together with additional evidence that cells “package” proteins in EVs systematically and according to their phenotypic state.

Bilirubin Prevents Atherosclerotic Lesion Formation in Low-Density Lipoprotein Receptor-Deficient Mice by Inhibiting Endothelial VCAM-1 and ICAM-1 Signaling

Background

Numerous epidemiological studies support an inverse association between serum bilirubin levels and the incidence of cardiovascular disease; however, the mechanism(s) by which bilirubin may protect against atherosclerosis is undefined. The goals of the present investigations were to assess the ability of bilirubin to prevent atherosclerotic plaque formation in low‐density lipoprotein receptor‐deficient (Ldlr^−/−) mice and elucidate the molecular processes underlying this effect.

Methods and Results

Bilirubin, at physiological concentrations (≤20 μmol/L), dose‐dependently inhibits THP‐1 monocyte migration across tumor necrosis factor α–activated human umbilical vein endothelial cell monolayers without altering leukocyte binding or cytokine production. A potent antioxidant, bilirubin effectively blocks the generation of cellular reactive oxygen species induced by the cross‐linking of endothelial vascular cell adhesion molecule 1 (VCAM‐1) or intercellular adhesion molecule 1 (ICAM‐1). These findings were validated by treating cells with blocking antibodies or with specific inhibitors of VCAM‐1 and ICAM‐1 signaling. When administered to Ldlr^−/− mice on a Western diet, bilirubin (30 mg/kg intraperitoneally) prevents atherosclerotic plaque formation, but does not alter circulating cholesterol or chemokine levels. Aortic roots from bilirubin‐treated animals exhibit reduced lipid and collagen deposition, decreased infiltration of monocytes and lymphocytes, fewer smooth muscle cells, and diminished levels of chlorotyrosine and nitrotyrosine, without changes in VCAM‐1 or ICAM‐1 expression.

Conclusions

Bilirubin suppresses atherosclerotic plaque formation in Ldlr^−/− mice by disrupting endothelial VCAM‐1‐ and ICAM‐1‐mediated leukocyte migration through the scavenging of reactive oxygen species signaling intermediaries. These findings suggest a potential mechanism for the apparent cardioprotective effects of bilirubin.

A Phenanthrene Derivative, 5,7-Dimethoxy-1,4-Phenanthrenequinone, Inhibits Cell Adhesion Molecule Expression and Migration in Vascular Endothelial and Smooth Muscle Cells

The activation of endothelial cells (ECs) and migration of vascular smooth muscle cells (VSMCs) have played a crucial role in monocyte chemotaxis/adhesion and intima thickening during vascular injury and atherosclerosis, respectively. Several phenanthrenes isolated from plants and natural products have been shown to possess different bioactivities such as anti-platelet aggregation and anti-inflammation. The current study was designated to investigate the effects of a phenanthrene derivative, 5,7-dimethoxy-1,4-phenanthrenequinone (DMPQ), on cell adhesion molecule (CAM) expression in vascular ECs and migration in VSMCs. The DMPQ attenuated monocyte-EC interaction but it did not affect monocyte adhesion to matrix. In parallel, DMPQ reduced tumor necrosis factor-α (TNF-α)-induced intercellular adhesion molecule and vascular CAM expression in ECs. DMPQ compromised TNF-α-induced IκB activation, nuclear factor-kappa B (NF-κB) translocation, and NF-κB-DNA complex formation. Moreover, it affected TNF-α- and hydrogen peroxide (H2O2)-induced reactive oxygen species production and IκB activation. These suggest that DMPQ affects CAM expression by affecting NF-κB signaling. Meanwhile, DMPQ could also inhibit platelet-derived growth factor (PDGF)-induced VSMC migration toward collagen by affecting cellular PDGF signaling, including PDGFRβ, PLCγ, ERK1/2, and Akt phosphorylation. The VSMC adhesion to collagen and collagen-induced focal adhesion kinase activation during cell adhesion were impaired by DMPQ treatment. This study reveals a phenanthrene derivative-DMPQ-with anti-inflammatory and anti-migratory bioactivity toward vascular ECs and SMCs, suggesting its protective effect on vascular injuries.