RhoA/Rho-associated kinase pathway selectively regulates thrombin-induced intercellular adhesion molecule-1 expression in endothelial cells via activation of I kappa B kinase beta and phosphorylation of RelA/p65

Rho-GTPases subfamily: cellular defectors orchestrating viral infection

Ras homolog gene family-guanosine triphosphatases (Rho-GTPases), key molecular switches regulating cytoskeletal dynamics and cellular signaling, play a pivotal role in viral infections by modulating critical processes such as viral entry, replication, and release. This review elucidates the intricate mechanisms through which Rho-GTPases, via interactions with guanine nucleotide exchange factors (GEFs), GTPase-activating proteins (GAPs), and other signaling pathways, including the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), rat sarcoma (Ras), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways, facilitate viral pathogenesis. Specific viruses, such as influenza A virus (IAV), herpesviruses, human immunodeficiency virus (HIV), and respiratory syncytial virus (RSV), exploit Rho-GTPase-mediated cytoskeletal reorganization to enhance infectivity. For example, Rho-GTPases promote actin remodeling and membrane fusion, which are essential for viral entry and intracellular transport. Furthermore, Rho-GTPases modulate immune responses, often suppressing antiviral defenses to favor viral replication. Despite these insights, the molecular mechanisms underlying Rho-GTPase regulation during viral infections remain incompletely understood. Future research should focus on delineating the precise roles of Rho-GTPases in distinct viral life cycles, uncovering novel regulatory mechanisms, and developing targeted antiviral therapies that selectively inhibit Rho-GTPase signaling without compromising host cell functions. Such advancements could pave the way for broad-spectrum antiviral strategies, particularly against viruses that heavily rely on cytoskeletal manipulation for infection.

Oxymatrine for inflammatory bowel disease in preclinical studies: a systematic review and meta-analysis

Background

Inflammatory Bowel Disease (IBD) is a chronic, idiopathic inflammatory disorder of the intestines. Oxymatrine (OMT) is a naturally active substance found in the desiccated roots of Sophora flavescens. It possesses anti-tumor, antiviral, and anti-inflammatory properties. In recent years, its therapeutic role in IBD has gradually been discovered. This review aims to explore the impact of OMT on inflammatory bowel disease by animal models.

Methods

Conduct a systematic search in the PubMed, Embase, Web of Science, Cochrane, and Medline databases. Using SYRCLE's risk of bias tool to assess the bias risk and quality of the included studies. For some data presented as figures, Web Plot Digitizer 4.2 software was used to extract it. STATA 16.0 was selected for the final meta-analysis.

Results

After rigorous literature screening, 12 studies were included. The data analysis results indicated that the disease activity index (DAI), histopathological score (HS), interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), nuclear factor-κB (NF-κB), and myeloperoxidase (MPO) activity in the IBD animal models significantly decreased following intervention with oxymatrine. Furthermore, OMT also extended the colon length in the animal models and improved the expression level of zonula occludens-1(ZO-1) and occludin. These results suggested that OMT may improve the condition of IBD through anti-inflammatory, antioxidative stress and protecting the intestinal barrier.

Conclusion

Meta-analysis suggests oxymatrine positively affects IBD animal models. This provides new insights for the clinical treatment of inflammatory bowel disease.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/view/CRD42024570580, identifier [CRD42024570580].

Extravasation of immune and tumor cells from an endothelial perspective

Crossing the vascular endothelium is a necessary stage for circulating cells aiming to reach distant organs. Leukocyte passage through the endothelium, known as transmigration, is a multistep process during which immune cells adhere to the vascular wall, migrate and crawl along the endothelium until they reach their exit site. Similarly, circulating tumor cells (CTCs), which originate from the primary tumor or reseed from early metastatic sites, disseminate using the blood circulation and also must cross the endothelial barrier to set new colonies in distant organs. CTCs are thought to mimic arrest and extravasation utilized by leukocytes; however, their extravasation also requires processes that, from an endothelial perspective, are specific to cancer cells. Although leukocyte extravasation relies on maintaining endothelial impermeability, it appears that cancer cells can indoctrinate endothelial cells into promoting their extravasation independently of their normal functions. In this Review, we summarize the common and divergent mechanisms of endothelial responses during extravasation of leukocytes (in inflammation) and CTCs (in metastasis), and highlight how these might be leveraged in the development of anti-metastatic treatments.

A systematic review on anti-diabetic action of 7-O-galloyl-D-sedoheptulose, a polyphenol from Corni Fructus, in type 2 diabetic mice with hepatic and pancreatic damage

Traditional medicines are recently being focused on to treat diabetes and its complications because of their lack of toxic and/or side effects. This report describes the effects of 7-O-galloyl-D-sedoheptulose (GS), a polyphenolic compound isolated from Corni Fructus, on type 2 diabetic db/db mice with hepatic and pancreatic damage. We examined several biochemical factors and oxidative stress- and inflammation-related markers. In the serum, levels of glucose, leptin, insulin, C-peptide, resistin, tumor necrosis factor-α, and interleukin-6 were down-regulated, while adiponectin was augmented by GS treatment. In addition, GS suppressed the reactive oxygen species and lipid peroxidation in the serum, liver, and pancreas, but increased the pancreatic insulin and pancreatic C-peptide contents. These results were derived from attenuating the expression of nicotinamide adenine dinucleotide phosphate oxidase subunit proteins, Nox-4 and p22^phox. Augmented nuclear factor (NF)-E2-related factor 2 and heme oxygenase-1 were reduced with a decrease in oxidative stress during GS treatment. NF-κB-related pro-inflammatory factors were also alleviated in hepatic tissue. Moreover, GS modulated the protein expressions of pro-inflammatory NF-κB, cyclooxygenase-2, inducible nitric oxide synthase, c-Jun N-terminal kinase (JNK), phosphor-JNK, activator protein-1, transforming growth factor-β₁, and fibronectin. Based on these results, we demonstrated that the anti-diabetic action of GS may be due to its anti-oxidative stress property and anti-inflammatory action.

Three Major Causes of Metabolic Retinal Degenerations and Three Ways to Avoid Them

An imbalance of homeostasis in the retina leads to neuron loss and this eventually results in a deterioration of vision. If the stress threshold is exceeded, different protective/survival mechanisms are activated. Numerous key molecular actors contribute to prevalent metabolically induced retinal diseases-the three major challenges are age-related alterations, diabetic retinopathy and glaucoma. These diseases have complex dysregulation of glucose-, lipid-, amino acid or purine metabolism. In this review, we summarize current knowledge on possible ways of preventing or circumventing retinal degeneration by available methods. We intend to provide a unified background, common prevention and treatment rationale for these disorders and identify the mechanisms through which these actions protect the retina. We suggest a role for herbal medicines, internal neuroprotective substances and synthetic drugs targeting four processes: parainflammation and/or glial cell activation, ischemia and related reactive oxygen species and vascular endothelial growth factor accumulation, apoptosis and/or autophagy of nerve cells and an elevation of ocular perfusion pressure and/or intraocular pressure. We conclude that in order to achieve substantial preventive or therapeutic effects, at least two of the mentioned pathways should be targeted synergistically. A repositioning of some drugs is considered to use them for the cure of the other related conditions.

GEF-H1/RhoA signaling pathway mediates pro-inflammatory effects of NF-κB on CD40L-induced pulmonary endothelial cells

One of the key targets of the inflammatory response in acute lung injury (ALI) is the human pulmonary micro-vascular endothelial cells (HPMVECs). Owing to its role in the activation of endothelial cells (ECs), CD40L figures prominently in the pathogenesis of ALI. Increasing evidences have showed that CD40L mediates inflammatory effects on ECs, at least in part, by triggering NF-κB-dependent gene expression. However, the mechanisms of such signal transmission remain unknown. In this study, we found that CD40L stimulated the transactivation of NF-κB and expression of its downstream cytokines in a p38 MAPK-dependent mechanism in HPMVECs. In addition, CD40L-mediated inflammatory effects might be correlated with the activation of the IKK/IκB/NF-κB pathway and nuclear translocation of NF-κB, being accompanied by dynamic cytoskeletal changes. GEF-H1/RhoA signaling is best known for its role in regulating cytoskeletal rearrangements. An interesting finding was that CD40L induced the activation of p38 and IKK/IκB, and the subsequent transactivation of NF-κB via GEF-H1/RhoA signaling. The critical role of GEF-H1/RhoA in CD40L-induced inflammatory responses in the lung was further confirmed in GEF-H1 and RhoA knockout mouse models, both of which were established by adeno-associated virus (AAV)-mediated delivery of sgRNAs into mice with EC-specific Cas9 expression. These results taken together suggested that p38 and IKK/IκB-mediated signaling pathways, both of which lied downstream of GEF-H1/RhoA, may coordinately regulate the transactivation of NF-κB in CD40L-activated HPMVECs. These findings may help to determine key pharmacological targets of intervention for CD40L-activated inflammatory effects associated with ALI.

Therapeutic Targeting of NF-κB in Acute Lung Injury: A Double-Edged Sword

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a devastating disease that can be caused by a variety of conditions including pneumonia, sepsis, trauma, and most recently, COVID-19. Although our understanding of the mechanisms of ALI/ARDS pathogenesis and resolution has considerably increased in recent years, the mortality rate remains unacceptably high (~40%), primarily due to the lack of effective therapies for ALI/ARDS. Dysregulated inflammation, as characterized by massive infiltration of polymorphonuclear leukocytes (PMNs) into the airspace and the associated damage of the capillary-alveolar barrier leading to pulmonary edema and hypoxemia, is a major hallmark of ALI/ARDS. Endothelial cells (ECs), the inner lining of blood vessels, are important cellular orchestrators of PMN infiltration in the lung. Nuclear factor-kappa B (NF-κB) plays an essential role in rendering the endothelium permissive for PMN adhesion and transmigration to reach the inflammatory site. Thus, targeting NF-κB in the endothelium provides an attractive approach to mitigate PMN-mediated vascular injury, not only in ALI/ARDS, but in other inflammatory diseases as well in which EC dysfunction is a major pathogenic mechanism. This review discusses the role and regulation of NF-κB in the context of EC inflammation and evaluates the potential and problems of targeting it as a therapy for ALI/ARDS.

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.

Microtubules as Major Regulators of Endothelial Function: Implication for Lung Injury

Endothelial dysfunction has been attributed as one of the major complications in COVID-19 patients, a global pandemic that has already caused over 4 million deaths worldwide. The dysfunction of endothelial barrier is characterized by an increase in endothelial permeability and inflammatory responses, and has even broader implications in the pathogenesis of acute respiratory syndromes such as ARDS, sepsis and chronic illnesses represented by pulmonary arterial hypertension and interstitial lung disease. The structural integrity of endothelial barrier is maintained by cytoskeleton elements, cell-substrate focal adhesion and adhesive cell junctions. Agonist-mediated changes in endothelial permeability are directly associated with reorganization of actomyosin cytoskeleton leading to cell contraction and opening of intercellular gaps or enhancement of cortical actin cytoskeleton associated with strengthening of endothelial barrier. The role of actin cytoskeleton remodeling in endothelial barrier regulation has taken the central stage, but the impact of microtubules in this process remains less explored and under-appreciated. This review will summarize the current knowledge on the crosstalk between microtubules dynamics and actin cytoskeleton remodeling, describe the signaling mechanisms mediating this crosstalk, discuss epigenetic regulation of microtubules stability and its nexus with endothelial barrier maintenance, and overview a role of microtubules in targeted delivery of signaling molecules regulating endothelial permeability and inflammation.

Role of ROCK/NF‑κB/AQP8 signaling in ethanol‑induced intestinal epithelial barrier dysfunction

The present study aimed to investigate the signaling pathways and the underlying molecular mechanisms involved in ethanol‑induced intestinal epithelial barrier (IEB) dysfunction. Therefore, an in vitro experimental model of IEB was established using an ethanol‑treated Caco‑2 intestinal epithelial cell monolayer. The results confirmed that Rho‑associated kinases (ROCKs), namely ROCK1 and ROCK2, were involved in the underlying pathway of ethanol‑induced IEB dysfunction. Ethanol exposure significantly increased the expression of both ROCK isoforms and the activity of nuclear factor κB (NF‑κB). Furthermore, ROCK1‑ and ROCK2‑specific small interfering RNAs (siRNAs), and the NF‑κB inhibitor ammonium pyrrolidine dithiocarbamate partially inhibited transepithelial electrical resistance in Caco‑2 cells in an in vitro IEB model. In addition, ROCK1‑ and ROCK2‑specific siRNAs inhibited the activity of NF‑κB, thereby downregulating the expression of aquaporin 8 (AQP8). Taken together, the results of the present study suggested that ROCK1/ROCK2‑mediated activation of NF‑κB and upregulation of AQP8 expression levels may represent a novel mechanism of ethanol‑induced impairment of IEB function.

Neuregulin‑1: An underlying protective force of cardiac dysfunction in sepsis (Review)

Neuregulin-1 (NRG-1) is a type of epidermal growth factor‑like protein primarily distributed in the nervous and cardiovascular systems. When sepsis occurs, the incidence of cardiac dysfunction in myocardial injury is high and the mechanism is complicated. It directly causes myocardial cell damage, whilst also causing damage to the structure and function of myocardial cells, weakening of endothelial function and coronary microcirculation, autonomic dysfunction, and activation of myocardial inhibitory factors. Studies investigating NRG‑1 have been performed using a variety of methods, including in vitro models, and animal and human clinical trials; however, the results are not consistent. NRG‑1/ErbBs signaling is involved in a variety of cardiac processes, from the development of the myocardium and cardiac conduction systems to the promotion of angiogenesis in cardiomyocytes, and in cardio‑protective effects during injury. NRG‑1 may exert a multifaceted cardiovascular protective effect by activating NRG‑1/ErbBs signaling and regulating multiple downstream signaling pathways, thereby improving myocardial cell dysfunction in sepsis, and protecting cardiomyocytes and endothelial cells. It may alleviate myocardial microvascular endothelial injury in sepsis; its anti‑inflammatory effects inhibit the production of myocardial inhibitory factors in sepsis, improve myocardial ischemia, decrease oxidative stress, regulate the disruption to the homeostasis of the autonomic nervous system, improve diastolic function, and offer protective effects at multiple target sites. As the mechanism of action of NRG‑1 intersects with the pathways involved in the pathogenesis of sepsis, it may be applicable as a treatment strategy to numerous pathological processes in sepsis.

RhoE Fine-Tunes Inflammatory Response in Myocardial Infarction

BACKGROUND

Inflammatory response after myocardial infarction (MI) is essential for cardiac healing, whereas excessive and prolonged inflammation extends the infarction and promotes adverse cardiac remodeling. Understanding the mechanistic insight of these tightly controlled inflammatory processes has a significant impact on post-MI recovery and therapy. Here, we uncover the critical role of small GTPase RhoE in post-MI recovery and its clinical implication.

METHODS

Three genetic mouse lines are used: global RhoE knockout, cardiomyocyte-specific RhoE heterozygous, and cardiomyocyte-specific RhoE overexpression mice. A set of molecular signaling experiments, including bimolecular fluorescence complementation, immunoprecipitation, electrophoretic mobility shift assay, and mRNA microarray analysis, were conducted. Permanent ligation of the left anterior descending artery was performed, followed by the assessments of cardiac function, inflammation, and survival in the first week after MI. Finally, we examined the correlation of the expression levels of RhoE in MI patient heart and patient prognosis.

RESULTS

RhoE deficiency turns on a group of proinflammatory gene expressions in mouse heart. Mice with cardiomyocyte-specific haploinsufficiency exhibit excessive inflammatory response with deleterious cardiac function after MI. A profound increase in nuclear factor-κB activity is detected in the mutant heart and the isolated cardiomyocytes. We further find that the expression of RhoE is upregulated in response to MI. Mechanistically, RhoE interacts with p65 and p50 individually in cytosol and blocks their nuclear translocation. RhoE also occupies the dimerization domain of p65 and subsequently disrupts the heterodimerization between p65 and p50. Cardiac RhoE overexpression inhibits nuclear factor-κB activity, restrains post-MI inflammation, and improves cardiac function and survival. Consistently, we find that the expression level of RhoE is elevated in the heart of patients with MI and that the patients with a higher expression level of RhoE exhibit a better prognosis in cardiac function recovery.

CONCLUSIONS

The study uncovers RhoE as a new fine-tuning factor modulating MI-induced inflammation and promoting injured heart recovery. RhoE may serve as a new potential biomarker for the assessment of MI patient prognosis. Manipulation of RhoE could be as a potential therapeutic approach for MI and other inflammatory diseases.

Short-Term Microgravity Influences Cell Adhesion in Human Breast Cancer Cells

With the commercialization of spaceflight and the exploration of space, it is important to understand the changes occurring in human cells exposed to real microgravity (r-µg) conditions. We examined the influence of r-µg, simulated microgravity (s-µg, incubator random positioning machine (iRPM)), hypergravity (hyper-g), and vibration (VIB) on triple-negative breast cancer (TNBC) cells (MDA-MB-231 cell line) with the aim to study early changes in the gene expression of factors associated with cell adhesion, apoptosis, nuclear factor "kappa-light-chain-enhancer" of activated B-cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling. We had the opportunity to attend a parabolic flight (PF) mission and to study changes in RNA transcription in the MDA-MB cells exposed to PF maneuvers (29th Deutsches Zentrum für Luft- und Raumfahrt (DLR) PF campaign). PF maneuvers induced an early up-regulation of ICAM1, CD44 and ERK1 mRNAs after the first parabola (P1) and a delayed upregulation of NFKB1, NFKBIA, NFKBIB, and FAK1 after the last parabola (P31). ICAM-1, VCAM-1 and CD44 protein levels were elevated, whereas the NF-κB subunit p-65 and annexin-A2 protein levels were reduced after the 31st parabola (P31). The PRKCA, RAF1, BAX mRNA were not changed and cleaved caspase-3 was not detectable in MDA-MB-231 cells exposed to PF maneuvers. Hyper-g-exposure of the cells elevated the expression of CD44 and NFKBIA mRNAs, iRPM-exposure downregulated ANXA2 and BAX, whereas VIB did not affect the TNBC cells. The early changes in ICAM-1 and VCAM-1 and the rapid decrease in the NF-κB subunit p-65 might be considered as fast-reacting, gravity-regulated and cell-protective mechanisms of TNBC cells exposed to altered gravity conditions. This data suggest a key role for the detected gravity-signaling elements in three-dimensional growth and metastasis.

Rho and Reactive Oxygen Species at Crossroads of Endothelial Permeability and Inflammation

Significance: Increased endothelial permeability and inflammation are two major hallmarks of the life-threatening conditions such as acute respiratory distress syndrome and sepsis. There is a growing consensus in the field that the Rho family of small guanosine triphosphates are critical regulators of endothelial function at both physiological and pathological states. A basal level of reactive oxygen species (ROS) is essential for maintaining metabolic homeostasis, vascular tone, and angiogenesis; however, excessive ROS generation impairs endothelial function and promotes lung inflammation. In this review, we will focus on the role of Rho in control of endothelial function and also briefly discuss a nexus between ROS generation and Rho activation during endothelial dysfunction. Recent Advances: Extensive studies in the past decades have established that a wide range of barrier-disruptive and proinflammatory agonists activate the Rho pathway that, ultimately, leads to endothelial dysfunction via disruption of endothelial barrier and further escalation of inflammation. An increasing body of evidence suggests that a bidirectional interplay exists between the Rho pathway and ROS generation during endothelial dysfunction. Rac, a member of the Rho family, is directly involved in ROS production and ROS, in turn, activate RhoA, Rac, and Cdc42. Critical Issues: A precise mechanism of interaction between ROS generation and Rho activation and its impact on endothelial function needs to be elucidated. Future Directions: By employing advanced molecular techniques, the sequential cascades in the Rho-ROS crosstalk signaling axis need to be explored. The therapeutic potential of the Rho pathway inhibitors in endothelial-dysfunction associated cardiopulmonary disorders needs to be evaluated.

Passing the Vascular Barrier: Endothelial Signaling Processes Controlling Extravasation

A central function of the vascular endothelium is to serve as a barrier between the blood and the surrounding tissue of the body. At the same time, solutes and cells have to pass the endothelium to leave or to enter the bloodstream to maintain homeostasis. Under pathological conditions, for example, inflammation, permeability for fluid and cells is largely increased in the affected area, thereby facilitating host defense. To appropriately function as a regulated permeability filter, the endothelium uses various mechanisms to allow solutes and cells to pass the endothelial layer. These include transcellular and paracellular pathways of which the latter requires remodeling of intercellular junctions for its regulation. This review provides an overview on endothelial barrier regulation and focuses on the endothelial signaling mechanisms controlling the opening and closing of paracellular pathways for solutes and cells such as leukocytes and metastasizing tumor cells.

Critical role of autophagy regulator Beclin1 in endothelial cell inflammation and barrier disruption

Recent studies have implicated autophagy in several inflammatory diseases involving aberrant endothelial cell (EC) responses, such as acute lung injury (ALI). However, the mechanistic basis for a role of autophagy in EC inflammation and permeability remain poorly understood. In this study, we impaired autophagy by silencing the essential Beclin1 autophagy gene in human pulmonary artery EC. This resulted in reduced expression of proinflammatory genes in response to thrombin, a procoagulant and proinflammatory mediator whose concentration is elevated in many diseases including sepsis and ALI. These (Beclin1-depleted) cells also displayed a marked decrease in NF-κB activity secondary to impaired DNA binding of RelA/p65 in the nucleus, but exhibited normal IκBα degradation in the cytosol. Further analysis showed that Beclin1 knockdown was associated with impaired RelA/p65 translocation to the nucleus. Additionally, Beclin1 knockdown attenuated thrombin-induced phosphorylation of RelA/p65 at Ser536, a critical event necessary for the transcriptional activity of RelA/p65. Beclin1 silencing also protected against thrombin-induced EC barrier disruption by preventing the loss of VE-cadherin at adherens junctions. Moreover, Beclin1 knockdown reduced thrombin-induced phosphorylation/inactivation of actin depolymerizing protein Cofilin1 and thereby actin stress fiber formation required for EC permeability as well as RelA/p65 nuclear translocation. Together, these data identify Beclin1 as a novel mechanistic link between autophagy and EC dysfunction (inflammation and permeability).

ROCK Inhibition Drives Resolution of Acute Inflammation by Enhancing Neutrophil Apoptosis

Uncontrolled inflammation leads to tissue damage and it is central for the development of chronic inflammatory diseases and autoimmunity. An acute inflammatory response is finely regulated by the action of anti-inflammatory and pro-resolutive mediators, culminating in the resolution of inflammation and restoration of homeostasis. There are few studies investigating intracellular signaling pathways associated with the resolution of inflammation. Here, we investigate the role of Rho-associated kinase (ROCK), a serine/threonine kinase, in a model of self-resolving neutrophilic inflammatory. We show that ROCK activity, evaluated by P-MYPT-1 kinetics, was higher during the peak of lipopolysaccharide-induced neutrophil influx in the pleural cavity of mice. ROCK inhibition by treatment with Y-27632 decreased the accumulation of neutrophils in the pleural cavity and was associated with an increase in apoptotic events and efferocytosis, as evaluated by an in vivo assay. In a model of gout, treatment with Y-27632 reduced neutrophil accumulation, IL-1β levels and hypernociception in the joint. These were associated with reduced MYPT and IκBα phosphorylation levels and increased apoptosis. Finally, inhibition of ROCK activity also induced apoptosis in human neutrophils and destabilized cytoskeleton, extending the observed effects to human cells. Taken together, these data show that inhibition of the ROCK pathway might represent a potential therapeutic target for neutrophilic inflammatory diseases.

Neuregulin‑1 protects cardiac function in septic rats through multiple targets based on endothelial cells

The primary mechanism underlying sepsis-induced cardiac dysfunction is loss of endothelial barrier function. Neuregulin-1 (NRG-1) exerts its functions on multiple targets. The present study aimed to identify the protective effects of NRG-1 in myocardial cells, including endothelial, anti-inflammatory and anti-apoptotic effects. Subsequent to lipopolysaccharide (LPS)-induced sepsis, rats were administered with either a vehicle or recombinant human NRG-1 (rhNRG-1; 10 µg/kg/day) for one or two days. H9c2 cardio-myoblasts were subjected to LPS (10 µg/ml) treatment for 12 and 24 h with or without rhNRG-1 (1 µg/ml). Survival rates were recorded at 48 h following sepsis induction. The hemo-dynamic method was performed to evaluate cardiac function, and myocardial morphology was observed. Von Willebrand Factor levels were detected using an immunofluorescence assay. Serum levels of tumor necrosis factor α, interleukin-6, intercellular cell adhesion molecule-1 and vascular endothelial growth factor were detected using an enzyme-linked immuno-sorbent assay; the reductase method was performed to detect serum nitric oxide levels. Apoptosis rates were determined using terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Ras homolog family member A (RhoA) and Rho-associated protein kinase 1 (ROCK1) protein levels were assessed using western blotting. Transmission electron microscopy was used to observe endothelial cells and myocardial ultrastructure changes. Results revealed that NRG-1-treated rats displayed less myocardial damage compared with sham rats. NRG-1 administration strengthened the barrier function of the vasculature, reduced the secretion of endothelial-associated biomarkers and exerted anti-inflammatory and anti-apoptotic effects. In addition, NRG-1 inhibited RhoA and ROCK1 signaling. The results revealed that NRG-1 improves cardiac function, increases the survival rate of septic rats and exerts protective effects via multiple targets throughout the body. The present results contribute to the development of a novel approach to reverse damage to myocardial and endothelial cells during sepsis.

Small GTPase RHOE/RND3, a new critical regulator of NF-κB signalling in glioblastoma multiforme?

Objectives

Abnormal activation of NF‐κB signalling is a major mechanism of apoptosis resistance in glioblastoma multiforme (GBM). Therefore, better understanding of the regulation of NF‐κB signalling has a significant impact for GBM therapy. Here, we uncovered a critical role of the small GTPase RND3 in regulating the p65 subunit of NF‐κB and NF‐κB signalling in GBM.

Materials and methods

Human GBM samples, GBM cells and a human orthotopic GBM‐xenografted animal model were used. The mechanisms of RND3 in regulation of NF‐κB signalling and GBM cell apoptosis were examined by luciferase assay, quantitative PCR, immunostaining, immunoblotting, immunofluorescence, coimmunoprecipitation, TUNEL staining, JC‐1 analysis and flow cytometry.

Results

Overexpression of RND3 led to reduced p65 activity in GBM‐cultured cells and a GBM animal model, indicating that the NF‐κB pathway is negatively regulated by RND3 in GBM. Mechanistically, we found that RND3 bound p65 and promoted p65 ubiquitination, leading to decreased p65 protein levels. Furthermore, RND3 enhanced cleaved caspase 3 levels and promoted apoptosis in GBM cells, and RND3 expression was positively correlated with cleaved caspase 3 and IL‐8 in human GBM samples. The effect of RND3 on promoting apoptosis disappeared when p65 ubiquitination was blocked by protease inhibitor carfilzomib or upon co‐expression of ectopic p65.

Conclusions

RND3 binds p65 protein and promotes its ubiquitination, resulting in reduced p65 protein expression and inhibition of NF‐κB signalling to induce GBM cell apoptosis.

Protective effects of oxymatrine against DSS-induced acute intestinal inflammation in mice via blocking the RhoA/ROCK signaling pathway

Oxymatrine (OMT) is an important quinoxaline alkaloid that has a wide range of pharmacological effects and has been shown to alleviate ulcerative colitis due to its profound anti-inflammatory effects. The RhoA/ROCK (Rho kinase) signaling pathway has been shown to be related to the pathogenesis of several autoimmune diseases; however, the specific mechanisms of RhoA/ROCK signaling in inflammatory bowel disease (IBD) remain elusive. Therefore, we sought to determine whether OMT could ameliorate acute intestinal inflammation by targeting the RhoA/ROCK signaling pathway. The potential therapeutic effect of OMT on acute intestinal inflammation and its impact on the RhoA/ROCK signaling pathway were assessed in six groups of mice treated with low, medium and high doses of OMT (25, 50 and 100 mg/kg, respectively), and an inhibitor of ROCK, Y-27632, as a positive control, after initiating dextran sodium sulfate (DSS)-induced acute intestinal inflammation. The model group and normal group were injected intraperitoneally with equal doses of PBS. Our results showed that OMT treatment could protect the integrity of the epithelial barrier, relieve oxidative stress, inhibit the expression of inflammatory mediators and pro-inflammatory cytokines, restrain the differentiation of Th17 cells and promote the differentiation of Treg cells via inhibition of the RhoA/ROCK pathway, thus providing therapeutic benefits for ulcerative colitis (UC). Therefore, inhibiting the RhoA/ROCK pathway might be a new approach that can be used in UC therapy, which deserves to be investigated further.

ROCK2 Regulates Monocyte Migration and Cell to Cell Adhesion in Vascular Endothelial Cells

The small GTPase Rho and its downstream effector, Rho-kinase (ROCK), regulate various cellular functions, including organization of the actin cytoskeleton, cell adhesion and migration. A pro-inflammatory lipid mediator, lysophosphatidic acid (LPA), is a potent activator of the Rho/ROCK signalling pathway and has been shown to induce the expression of chemokines and cell adhesion molecules (CAMs). In the present study, we aimed to elucidate the precise mechanism by which ROCK regulates LPA-induced expressions and functions of chemokines and CAMs. We observed that ROCK blockade reduced LPA-induced phosphorylation of IκBα and inhibited NF-κB RelA/p65 phosphorylation, leading to attenuation of RelA/p65 nuclear translocation. Furthermore, small interfering RNA-mediated ROCK isoform knockdown experiments revealed that LPA induces the expression of monocyte chemoattractant protein-1 (MCP-1) and E-selectin via ROCK2 in human aortic endothelial cells (HAECs). Importantly, we found that ROCK2 but not ROCK1 controls LPA-induced monocytic migration and monocyte adhesion toward endothelial cells. These findings demonstrate that ROCK2 is a key regulator of endothelial inflammation. We conclude that targeting endothelial ROCK2 is potentially effective in attenuation of atherosclerosis.

Staphylococcus aureus-induced endothelial permeability and inflammation are mediated by microtubule destabilization

Staphylococcus aureus is a major etiological agent of sepsis and induces endothelial cell (EC) barrier dysfunction and inflammation, two major hallmarks of acute lung injury. However, the molecular mechanisms of bacterial pathogen-induced EC barrier disruption are incompletely understood. Here, we investigated the role of microtubules (MT) in the mechanisms of EC barrier compromise caused by heat-killed S. aureus (HKSA). Using a customized monolayer permeability assay in human pulmonary EC and MT fractionation, we observed that HKSA-induced barrier disruption is accompanied by MT destabilization and increased histone deacetylase-6 (HDAC6) activity resulting from elevated reactive oxygen species (ROS) production. Molecular or pharmacological HDAC6 inhibition rescued barrier function in HKSA-challenged vascular endothelium. The HKSA-induced EC permeability was associated with impaired MT-mediated delivery of cytoplasmic linker-associated protein 2 (CLASP2) to the cell periphery, limiting its interaction with adherens junction proteins. HKSA-induced EC barrier dysfunction was also associated with increased Rho GTPase activity via activation of MT-bound Rho-specific guanine nucleotide exchange factor-H1 (GEF-H1) and was abolished by HDAC6 down-regulation. HKSA activated the NF-κB proinflammatory pathway and increased the expression of intercellular and vascular cell adhesion molecules in EC, an effect that was also HDAC6-dependent and mediated, at least in part, by a GEF-H1/Rho-dependent mechanism. Of note, HDAC6 knockout mice or HDAC6 inhibitor-treated WT mice were partially protected from vascular leakage and inflammation caused by both HKSA or methicillin-resistant S. aureus (MRSA). Our results indicate that S. aureus-induced, ROS-dependent up-regulation of HDAC6 activity destabilizes MT and thereby activates the GEF-H1/Rho pathway, increasing both EC permeability and inflammation.

Rho-Associated Coiled-Coil Kinase (ROCK) in Molecular Regulation of Angiogenesis

Identified as a major downstream effector of the small GTPase RhoA, Rho-associated coiled-coil kinase (ROCK) is a versatile regulator of multiple cellular processes. Angiogenesis, the process of generating new capillaries from the pre-existing ones, is required for the development of various diseases such as cancer, diabetes and rheumatoid arthritis. Recently, ROCK has attracted attention for its crucial role in angiogenesis, making it a promising target for new therapeutic approaches. In this review, we summarize recent advances in understanding the role of ROCK signaling in regulating the permeability, migration, proliferation and tubulogenesis of endothelial cells (ECs), as well as its functions in non-ECs which constitute the pro-angiogenic microenvironment. The therapeutic potential of ROCK inhibitors in angiogenesis-related diseases is also discussed.

The Ocular Hypotensive Efficacy of Topical Fasudil, a Rho-Associated Protein Kinase Inhibitor, in Patients With End-Stage Glaucoma

To investigate the effects of topical administration of a selective Rho-associated kinase (ROCK) inhibitor, fasudil 0.5% and 1.2% in glaucomatous patients. In this interventional case series study, 4 eyes of 4 patients with unilateral end-stage primary open-angle glaucoma and no light perception vision were assigned to receive topical fasudil 0.5% (in 3 eyes) or 1.2% (in 1 eye) ophthalmic solution twice daily for 8 weeks. At weeks 1, 2, 3, 4, and 8, intraocular pressure (IOP) and adverse events were evaluated. Baseline mean IOP was 53.5 ± 3.4 mm Hg and mean IOP reductions of the last visit were -8.25 ± 1.2 mm Hg at 2 hours and -8.75 ± 2.2 mm Hg at 4 hours. Mean IOP reductions were clinically and statistically significant with 0.5% and 1.2% fasudil and peak effects occurred 2-4 hours after application (P = 0.0002). The largest IOP reductions were produced by 1.2% fasudil (up to -12 mm Hg). Conjunctival hyperemia was found in 1 patient with 1.2% fasudil. Topical administration of fasudil in end-stage primary open-angle glaucoma patients, caused reduction in IOP and was well tolerated. ROCK inhibitors could be considered as a candidate for glaucoma therapy in future.

Noncanonical Matrix Metalloprotease 1-Protease-Activated Receptor 1 Signaling Drives Progression of Atherosclerosis

OBJECTIVE

Protease-activated receptor-1 (PAR1) is classically activated by thrombin and is critical in controlling the balance of hemostasis and thrombosis. More recently, it has been shown that noncanonical activation of PAR1 by matrix metalloprotease-1 (MMP1) contributes to arterial thrombosis. However, the role of PAR1 in long-term development of atherosclerosis is unknown, regardless of the protease agonist.

APPROACH AND RESULTS

We found that plasma MMP1 was significantly correlated (R=0.33; P=0.0015) with coronary atherosclerotic burden as determined by angiography in 91 patients with coronary artery disease and acute coronary syndrome undergoing cardiac catheterization or percutaneous coronary intervention. A cell-penetrating PAR1 pepducin, PZ-128, currently being tested as an antithrombotic agent in the acute setting in the TRIP-PCI study (Thrombin Receptor Inhibitory Pepducin-Percutaneous Coronary Intervention), caused a significant decrease in total atherosclerotic burden by 58% to 70% (P<0.05) and reduced plaque macrophage content by 54% (P<0.05) in apolipoprotein E-deficient mice. An MMP1 inhibitor gave similar beneficial effects, in contrast to the thrombin inhibitor bivalirudin that gave no improvement on atherosclerosis end points. Mechanistic studies revealed that inflammatory signaling mediated by MMP1-PAR1 plays a critical role in amplifying tumor necrosis factor α signaling in endothelial cells.

CONCLUSIONS

These data suggest that targeting the MMP1-PAR1 system may be effective in tamping down chronic inflammatory signaling in plaques and halting the progression of atherosclerosis.

Importins α and β signaling mediates endothelial cell inflammation and barrier disruption

Nucleocytoplasmic shuttling via importins is central to the function of eukaryotic cells and an integral part of the processes that lead to many human diseases. In this study, we addressed the role of α and β importins in the mechanism of endothelial cell (EC) inflammation and permeability, important pathogenic features of many inflammatory diseases such as acute lung injury and atherosclerosis. RNAi-mediated knockdown of importin α4 or α3 each inhibited NF-κB activation, proinflammatory gene (ICAM-1, VCAM-1, and IL-6) expression, and thereby endothelial adhesivity towards HL-60 cells, upon thrombin challenge. The inhibitory effect of α4 and α3 knockdown was associated with impaired nuclear import and consequently, DNA binding of RelA/p65 subunit of NF-κB and occurred independently of IκBα degradation. Intriguingly, knockdown of importins α4 and α3 also inhibited thrombin-induced RelA/p65 phosphorylation at Ser536, showing a novel role of α importins in regulating transcriptional activity of RelA/p65. Similarly, knockdown of importin β1, but not β2, blocked thrombin-induced activation of RelA/p65 and its target genes. In parallel studies, TNFα-mediated inflammatory responses in EC were refractory to knockdown of importins α4, α3 or β1, indicating a stimulus-specific regulation of RelA/p65 and EC inflammation by these importins. Importantly, α4, α3, or β1 knockdown also protected against thrombin-induced EC barrier disruption by inhibiting the loss of VE-cadherin at adherens junctions and by regulating actin cytoskeletal rearrangement. These results identify α4, α3 and β1 as critical mediators of EC inflammation and permeability associated with intravascular coagulation.

Inhibition of Rho kinase protects against colitis in mice by attenuating intestinal epithelial barrier dysfunction via MLC and the NF-κB pathway

The aim of the present study was to investigate the role of Rho kinase (also known as ROCK) inhibitor in 2,4,6-trinitrobenzene sulfonic acid induced mouse colitis; and to elucidate the underlying mechanism of ROCK1/ROCK2 inhibition in enhancing intestinal epithelial barrier (IEB) function. A specific inhibitor of ROCK, Y-27632, was used to examine the role of ROCK in mouse colitis models. ROCK1 and ROCK2 were silenced respectively using RNA interference in Caco-2 cells. The expression of tight junction proteins and the downstream molecules of ROCK were assessed. Y-27632 alleviated colonic inflammation and decreased intestinal permeability. ROCK-myosin light chain (MLC) and ROCK-NF-κB pathway were activated in colitis and inhibited by Y-27632. In vitro, ROCK1 RNAi primarily downregulated the phosphorylation of myosin phosphatase-targeting subunit-1 (MYPT-1) and MLC, while ROCK2 RNAi inhibited phosphorylation of nuclear factor-κB (NF-κB). In conclusion, the results suggested that the ROCK inhibitor alleviated colitis and IEB dysfunction. Inhibition of phospho-MYPT-1 and MLC by ROCK1 knockout or inhibition of NF-κB phosphorylation by ROCK2 knockout may be the underlying mechanisms.

ROCK inhibitors for the treatment of ocular diseases

The Rho-kinase/ROCK (Rho-associated coiled-coil-containing protein kinase) pathway is involved in the pathogenesis of multiple ocular and systemic disorders. Recently, ROCK inhibitors have been suggested as novel treatments for various ocular diseases. Several in vitro, in vivo and clinical studies have demonstrated the safety and efficacy of ROCK inhibitors in the management of ocular disorders such as corneal epithelial and endothelial damage, glaucoma, retinal and choroidal neovascularisation, diabetic macular oedema and optic nerve disorders. In this review, these studies are explored with focus on the relevant clinical investigations.

Rho-Kinase/ROCK as a Potential Drug Target for Vitreoretinal Diseases

Rho-associated kinase (Rho-kinase/ROCK) was originally identified as an effector protein of the G protein Rho. Its involvement in various diseases, particularly cancer and cardiovascular disease, has been elucidated, and ROCK inhibitors have already been applied clinically for cerebral vasospasm and glaucoma. Vitreoretinal diseases including diabetic retinopathy, age-related macular degeneration, and proliferative vitreoretinoapthy are still a major cause of blindness. While anti-VEGF therapy has recently been widely used for vitreoretinal disorders due to its efficacy, attention has been drawn to new unmet needs. The importance of ROCK in pathological vitreoretinal conditions has also been elucidated and is attracting attention as a potential therapeutic target. ROCK is involved in angiogenesis and hyperpermeability and also in the pathogenesis of various pathologies such as inflammation and fibrosis. It has been expected that ROCK inhibitors will become new molecular target drugs for vitreoretinal diseases. This review summarizes the recent progress on the mechanisms of action of ROCK and their applications in disease treatment.

Sphingosine-1-phosphate restores endothelial barrier integrity in ovarian hyperstimulation syndrome

STUDY QUESTION

Are follicular fluid (FF) sphingosine-1-phosphate (S1P) levels in patients at risk of developing ovarian hyperstimulation syndrome (OHSS) altered and in part responsible for the high vascular permeability observed in these patients.

STUDY ANSWER

FF S1P levels are lower in FF from patients at risk of OHSS and treatment with S1P may reduce vascular permeability in these patients.

WHAT IS KNOWN ALREADY

Although advances have been made in the diagnosis, and management of OHSS and in basic knowledge of its development, complete prevention has proven difficult.

STUDY DESIGN, SIZE, DURATION

A total of 40 FF aspirates were collected from patients undergoing ART. The women (aged 25-39 years old) were classified into a control group (n = 20) or a group at risk of OHSS (n = 20). The EA.hy926 endothelial cell line was used to assess the efffects of FF from patients at risk of OHSS with or without the addition of S1P. An animal model that develops OHSS in immature Sprague-Dawley rats were also used.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Migration assays, confocal microscopy analysis of actin filaments, immunoblotting and quail chorioallantoic membrane (CAM) assays of in-vivo angiogenesis were performed and statistical comparisons between groups were made.

MAIN RESULTS AND THE ROLE OF CHANCE

The S1P concentration was significantly lower in FF from patients at risk of OHSS (P = 0.03). The addition of S1P to this FF decreased cell migration (P < 0.05) and prevented VE-cadherin phosphorylation in endothelial cells (P < 0.05). S1P in the FF from patients at risk of OHSS increased the levels of VE-cadherin (P < 0.05), N-cadherin (P < 0.05) and β-catenin (P < 0.05), and partially reversed actin redistribution in endothelial cells. The addition of S1P in FF from patients at risk of OHSS also decreased the levels of vascular endothelial growth factor (VEGF121; P < 0.01) and S1P lyase (SPL; P < 0.05) and increased the levels of S1PR1 (P < 0.05) in endothelial cells. In CAMs incubated with FF from patients at risk of OHSS with S1P, the number of vessel branch points decreased while the periendothelial cell coverage increased. Additionally, in a rat OHSS model, we demonstrated that vascular permeability and VEGF121 and its receptor KDR expression were increased in the OHSS group compared to the control group and that S1P administration decreased these parameters.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The results of this study were generated from an in-vitro system. This model reflects the microvasculature in vivo. Even though the ideal model would be the use of human endothelial cells from the ovary, it is obviously not possible to carry out this kind of approach in ovaries of patients from ART. More studies will be necessary to delineate the effects of S1P in the pathogenesis of OHSS. Hence, clinical studies are needed in order to choose the most appropriate method of prevention and management.

WIDER IMPLICATIONS OF THE FINDINGS

The use of bioactive sphingolipid metabolites may contribute to finding better and safer therapeutic strategies for the treatment of OHSS and other human diseases that display aberrant vascular leakage.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by grants ANPCyT (PICT 2012-897), CONICET (PIP 5471), Roemmers and Baron Foundation, Argentina. The authors declare no conflict of interest.

AMA0428, A Potent Rock Inhibitor, Attenuates Early and Late Experimental Diabetic Retinopathy

PURPOSE

Diabetic retinopathy (DR) is characterized by an early stage of inflammation and vessel leakage, and an advanced vasoproliferative stage. Also, neurodegeneration might play an important role in disease pathogenesis. The aim of this study was to investigate the effect of the Rho kinase (ROCK) inhibitor, AMA0428, on these processes.

METHODS

The response to ROCK inhibition by AMA0428 (1 µg) was studied in vivo using the murine model for streptozotocin (STZ)-induced diabetes, focusing on early non-proliferative DR features and the oxygen-induced retinopathy (OIR) model to investigate proliferative DR. Intravitreal (IVT) administration of AMA0428 was compared with murine anti-VEGF-R2 antibody (DC101, 6.2 µg) and placebo (H₂O/PEG; 1C8). Outcome was assessed by analyzing leukostasis using fluorescein isothiocyanate coupled concanavalin A (FITC-ConA) and vessel leakage (bovine serum albumin conjugated with fluorescein isothiocyanate; FITC-BSA)/neovascularization and neurodegeneration by immunohistological approaches (hematoxylin and eosin (H&E), terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling (TUNEL), Brn3a). ELISA and Western blotting were employed to unravel the consequences of ROCK inhibition (1 µM AMA0428) on myosin phosphatase target protein (MYPT)-1 phosphorylation, endothelial nitric oxide synthase (eNOS) phosphorylation, and vascular endothelial growth factor (VEGF) levels in retinas of diabetic mice, on NF-κβ activity and ICAM-1 expression in endothelial cells (ECs).

RESULTS

In vivo, AMA0428 significantly reduced vessel leakage and neovascularization, respectively, in the STZ and OIR model, comparable to DC101 therapy. Additionally, the ROCK inhibitor decreased neurodegeneration in both models and inhibited leukostasis by 30% (p < 0.05) in the STZ model (p < 0.05), while DC101 had no positive effect on the outcome of these latter processes. ROCK activity was upregulated in the diabetic retina and AMA0428 administration resulted in decreased phospho-MYPT-1, enhanced phospho-eNOS, and reduced VEGF levels. In vitro, AMA0428 interfered with NF-κβ activity, thereby inhibiting ICAM-1 expression in ECs.

CONCLUSIONS

Targeting ROCK with AMA0428 effectively attenuated outcome in an early DR model (STZ) and a late vasoproliferative retinopathy model (OIR). These findings make AMA0428 a promising candidate with an additional anti-inflammatory and neuroprotective benefit for DR patients, as compared with anti-VEGF treatment.

Phospholipase C-ε signaling mediates endothelial cell inflammation and barrier disruption in acute lung injury

Phospholipase C-ε (PLC-ε) is a unique PLC isoform that can be regulated by multiple signaling inputs from both Ras family GTPases and heterotrimeric G proteins and has primary sites of expression in the heart and lung. Whereas the role of PLC-ε in cardiac function and pathology has been documented, its relevance in acute lung injury (ALI) is unclear. We used PLC-ε(-/-) mice to address the role of PLC-ε in regulating lung vascular inflammation and injury in an aerosolized bacterial LPS inhalation mouse model of ALI. PLC-ε(-/-) mice showed a marked decrease in LPS-induced proinflammatory mediators (ICAM-1, VCAM-1, TNF-α, IL-1β, IL-6, macrophage inflammatory protein 2, keratinocyte-derived cytokine, monocyte chemoattractant protein 1, and granulocyte-macrophage colony-stimulating factor), lung neutrophil infiltration and microvascular leakage, and loss of VE-cadherin compared with PLC-ε(+/+) mice. These data identify PLC-ε as a critical determinant of proinflammatory and leaky phenotype of the lung. To test the possibility that PLC-ε activity in endothelial cells (EC) could contribute to ALI, we determined its role in EC inflammation and barrier disruption. RNAi knockdown of PLC-ε inhibited NF-κB activity in response to diverse proinflammatory stimuli, thrombin, LPS, TNF-α, and the nonreceptor agonist phorbol 13-myristate 12-acetate (phorbol esters) in EC. Depletion of PLC-ε also inhibited thrombin-induced expression of NF-κB target gene, VCAM-1. Importantly, PLC-ε knockdown also protected against thrombin-induced EC barrier disruption by inhibiting the loss of VE-cadherin at adherens junctions and formation of actin stress fibers. These data identify PLC-ε as a novel regulator of EC inflammation and permeability and show a hitherto unknown role of PLC-ε in the pathogenesis of ALI.

MicroRNA-155 contributes to shear-resistant leukocyte adhesion to human brain endothelium in vitro

Background

Increased leukocyte adhesion to brain endothelial cells forming the blood–brain barrier (BBB) precedes extravasation into the central nervous system (CNS) in neuroinflammatory diseases such as multiple sclerosis (MS). Previously, we reported that microRNA-155 (miR-155) is up-regulated in MS and by inflammatory cytokines in human brain endothelium, with consequent modulation of endothelial paracellular permeability. Here, we investigated the role of endothelial miR-155 in leukocyte adhesion to the human cerebral microvascular endothelial cell line, hCMEC/D3, under shear forces mimicking blood flow in vivo.

Results

Using a gain- and loss-of-function approach, we show that miR-155 up-regulation increases leukocyte firm adhesion of both monocyte and T cells to hCMEC/D3 cells. Inhibition of endogenous endothelial miR-155 reduced monocytic and T cell firm adhesion to naïve and cytokines-induced human brain endothelium. Furthermore, this effect is partially associated with modulation of the endothelial cell adhesion molecules VCAM1 and ICAM1 by miR-155.

Conclusions

Our results suggest that endothelial miR-155 contribute to the regulation of leukocyte adhesion at the inflamed BBB. Taken together with previous observations, brain endothelial miR-155 may constitute a potential molecular target for treatment of neuroinflammation diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12987-016-0032-3) contains supplementary material, which is available to authorized users.

Conditional knockout of polarity complex (atypical) PKCι reveals an anti-inflammatory function mediated by NF-κB

Atypical PKC, Par6, and Par3 constitute a conserved complex signaling cell asymmetry. In contrast to its role in other tissues, atypical PKC inhibits NF-κB activation in epithelia and may function in maintaining low levels of inflammation in addition to establishing apicobasal polarity.

The conserved proteins of the polarity complex made up of atypical PKC (aPKC, isoforms ι and ζ), Par6, and Par3 determine asymmetry in several cell types, from Caenorhabditis elegans oocytes to vertebrate epithelia and neurons. We previously showed that aPKC is down-regulated in intestinal epithelia under inflammatory stimulation. Further, expression of constitutively active PKCι decreases NF-κB activity in an epithelial cell line, the opposite of the effect reported in other cells. Here we tested the hypothesis that aPKC has a dual function in epithelia, inhibiting the NF-κB pathway in addition to having a role in apicobasal polarity. We achieved full aPKC down-regulation in small intestine villi and colon surface epithelium using a conditional epithelium-specific knockout mouse. The results show that aPKC is dispensable for polarity after cell differentiation, except for known targets, including ROCK and ezrin, claudin-4 expression, and barrier permeability. The aPKC defect resulted in increased NF-κB activity, which could be rescued by IKK and ROCK inhibitors. It also increased expression of proinflammatory cytokines. In contrast, expression of anti-inflammatory IL-10 decreased. We conclude that epithelial aPKC acts upstream of multiple mechanisms that participate in the inflammatory response in the intestine, including, but not restricted to, NF-κB.

Effect of adrenomedullin on intestinal permeability in rats with ulcerative colitis

AIM: To investigate the possible mechanism of adrenomedullin (AM) to protect the intestinal epithelial barrier function in a rat model of ulcerative colitis (UC).

METHODS: Twenty-four male Sprague-Dawley rats were randomly divided into three groups: a normal control group, a model group and an AM group. Each group contained 8 rats. All the rats except those in the normal control group were administered with TNBS to induce colitis. Rats in the normal control group was given physiological saline instead. Forty-eight hours after inducing colitis, in the AM group, AM (1.0 μg of AM diluted in 1.0 mL of saline) was injected into the lumen of the colon. Rats in the normal control group and model group were given 1.0 mL of saline instead. All of them were treated for seven consecutive days. Blood samples were collected to measure serum tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) levels by ELISA. Colon tissues were taken to detect the protein expression of RhoA, Rho associated kinase 1 (ROCK1), MLCK, nuclear factor-κB (NF-κB) p65 and Occludin by Western blot analysis.

RESULTS: All the rats induced with TNBS developed symptoms such as profound and sustained weight loss, bradykinesia and purulent and bloody stools. The levels of serum TNF-α and IFN-γ in model rats were significantly higher than those in the normal group (P < 0.05), however, serum TNF-α and IFN-γ were significantly decreased after AM treatment (P < 0.05). The expression levels of RhoA, ROCKI, MLCK and NF-κB p65 showed a significant increase in the model group compared with the normal group (P < 0.05), while treatment with AM clearly reduced their expression. The expression of Occludin in model rats was significantly decreased (P < 0.05), while in the AM group, the reduced Occludin expression appeared to resume (P < 0.05).

CONCLUSION: AM improves intestinal mucosal barrier function in UC possibly by regulating the NF-κB p65/MLCK signal pathway mediated by RhoA.

Intravitreal Injection of a Rho-Kinase Inhibitor (Fasudil) for Recent-Onset Nonarteritic Anterior Ischemic Optic Neuropathy

This study evaluated the effects of intravitreal injection of fasudil (IVF), a Rho-kinase inhibitor, in cases of recent-onset nonarteritic anterior ischemic optic neuropathy (NAION). In this interventional case series, 13 eyes of 13 patients diagnosed with NAION within 14 days of onset were included. The affected eyes received a 0.025 mg/0.05 mL IVF. Functional and structural outcomes were assessed 1 and 3 months following treatment. Best corrected visual acuity (BCVA) was the main outcome measured, with mean deviation (MD) index of the VF test and peripapillary retinal nerve fiber layer thickness as secondary measures. There was a statistically significant improvement in the patients' BCVA 1 and 3 months following IVF; BCVA improved from 1.69 ± 0.55 logMAR at baseline to 0.98 ± 0.47 and 0.93 ± 0.51 logMAR at 1 and 3 months, respectively (P = .004). The change in BCVA was not significant between month 1 and month 3 (P = .22). Peripapillary retinal nerve fiber layer thickness decreased from 173.5 ± 29.28 µm in the baseline evaluation to 85.8 ± 8.8 µm at 1 month, and 62.9 ± 5.97 µm at 3 months (P = .003). MD values changed from 24.60 ± 3.80 to 21.0 ± 6.10 and 20.5 ± 6.50 at 1 and 3 months, respectively (P = .007 and .005, respectively). This pilot study suggests that IVF may be an effective treatment for patients with recent-onset NAION. Larger studies are required to establish the therapeutic role of fasudil for NAION.

Effect of Rho-kinase Inhibitor, Y27632, on Porcine Corneal Endothelial Cell Culture, Inflammation and Immune Regulation

PURPOSE

To investigate the effect of the Rho-kinase inhibitor, Y27632, on pig corneal endothelial cell (pCEC) culture, and on inflammation and immune regulation of the responses of human cells to pCECs.

METHODS

pCECs were cultured with/without Y27632 to assess cell proliferation and in vitro wound healing assay. The level of MCP-1 and VEGF in pCECs stimulated with human TNF-α were measured. Proliferation of human PBMCs stimulated with pCECs, and cytokine production in human T cells, and monocyte migration after stimulation were investigated.

RESULTS

Y27632 promoted pCEC proliferation, prevented pCEC death, and enhanced in vitro wound healing. After stimulation, there were significantly lower levels of MCP-1 and VEGF measured in pCECs cultured with Y27632, and significantly reduced human PBMC proliferation, cytokine production, and monocyte migration.

CONCLUSIONS

The application of the Rho-kinase inhibitor will be beneficial when culturing pCECs, and may provide a novel therapy to reduce inflammation after corneal xenotransplantation.

G Protein-Coupled Receptor and RhoA-Stimulated Transcriptional Responses: Links to Inflammation, Differentiation, and Cell Proliferation

The low molecular weight G protein RhoA (rat sarcoma virus homolog family member A) serves as a node for transducing signals through G protein-coupled receptors (GPCRs). Activation of RhoA occurs through coupling of G proteins, most prominently, G12/13, to Rho guanine nucleotide exchange factors. The GPCR ligands that are most efficacious for RhoA activation include thrombin, lysophosphatidic acid, sphingosine-1-phosphate, and thromboxane A2. These ligands also stimulate proliferation, differentiation, and inflammation in a variety of cell and tissues types. The molecular events underlying these responses are the activation of transcription factors, transcriptional coactivators, and downstream gene programs. This review describes the pathways leading from GPCRs and RhoA to the regulation of activator protein-1, NFκB (nuclear factor κ-light-chain-enhancer of activated B cells), myocardin-related transcription factor A, and Yes-associated protein. We also focus on the importance of two prominent downstream transcriptional gene targets, the inflammatory mediator cyclooxygenase 2, and the matricellular protein cysteine-rich angiogenic inducer 61 (CCN1). Finally, we describe the importance of GPCR-induced activation of these pathways in the pathophysiology of cancer, fibrosis, and cardiovascular disease.

Elevated cytokines, thrombin and PAI-1 in severe HCPS patients due to Sin Nombre virus

Sin Nombre Hantavirus (SNV, Bunyaviridae Hantavirus) is a Category A pathogen that causes Hantavirus Cardiopulmonary Syndrome (HCPS) with case fatality ratios generally ranging from 30% to 50%. HCPS is characterized by vascular leakage due to dysregulation of the endothelial barrier function. The loss of vascular integrity results in non-cardiogenic pulmonary edema, shock, multi-organ failure and death. Using Electric Cell-substrate Impedance Sensing (ECIS) measurements, we found that plasma samples drawn from University of New Mexico Hospital patients with serologically-confirmed HCPS, induce loss of cell-cell adhesion in confluent epithelial and endothelial cell monolayers grown in ECIS cultureware. We show that the loss of cell-cell adhesion is sensitive to both thrombin and plasmin inhibitors in mild cases, and to thrombin only inhibition in severe cases, suggesting an increasing prothrombotic state with disease severity. A proteomic profile (2D gel electrophoresis and mass spectrometry) of HCPS plasma samples in our cohort revealed robust antifibrinolytic activity among terminal case patients. The prothrombotic activity is highlighted by acute ≥30 to >100 fold increases in active plasminogen activator inhibitor (PAI-1) which, preceded death of the subjects within 48 h. Taken together, this suggests that PAI-1 might be a response to the severe pathology as it is expected to reduce plasmin activity and possibly thrombin activity in the terminal patients.

Receptor proximal kinases in NF-κB signaling as potential therapeutic targets in cancer and inflammation

Many signaling pathways leading to activation of transcription factors and gene expression are characterized by phosphorylation events mediated by specific kinases. The transcription factor NF-κB plays a key role in multiple cellular processes, including immune signaling, inflammation, development, proliferation and survival. Dysregulated NF-κB activation is associated with autoimmunity, chronic inflammation and cancer. Activation of NF-κB requires IκB kinase (IKK)α or β, the activity of which is regulated via phosphorylation by specific IKK kinases and by autophosphorylation. Receptor specificity is further obtained by the use of multiple upstream receptor proximal kinases. We review the identities of several IKK regulatory kinases as well as the proposed molecular mechanisms. In addition, we discuss the potential for therapeutic targeting of some of these kinases in the context of inflammatory diseases and cancer.

Adenosine regulates the proinflammatory signaling function of thrombin in endothelial cells

The plasma level of the regulatory metabolite adenosine increases during the activation of coagulation and inflammation. Here we investigated the effect of adenosine on modulation of thrombin-mediated proinflammatory responses in HUVECs. We found that adenosine inhibits the barrier-disruptive effect of thrombin in HUVECs by a concentration-dependent manner. Analysis of cell surface expression of adenosine receptors revealed that A2A and A2B are expressed at the highest level among the four receptor subtypes (A2B  > A2A  > A1  > A3 ) on HUVECs. The barrier-protective effect of adenosine in response to thrombin was recapitulated by the A2A specific agonist, CGS 21680, and abrogated both by the siRNA knockdown of the A2A receptor and by the A2A -specific antagonists, ZM-241385 and SCH-58261. The thrombin-induced RhoA activation and its membrane translocation were both inhibited by adenosine in a cAMP-dependent manner, providing a molecular mechanism through which adenosine exerts a barrier-protective function. Adenosine also inhibited thrombin-mediated activation of NF-κB and decreased adhesion of monocytic THP-1 cells to stimulated HUVECs via down-regulation of expression of cell surface adhesion molecules, VCAM-1, ICAM-1, and E-selectin. Moreover, adenosine inhibited thrombin-induced elevated expression of proinflammatory cytokines, IL-6 and HMGB-1; and chemokines, MCP-1, CXCL-1, and CXCL-3. Taken together, these results suggest that adenosine may inhibit thrombin-mediated proinflammatory signaling responses, thereby protecting the endothelium from injury during activation of coagulation and inflammation.

Rho protein GTPases and their interactions with NFκB: crossroads of inflammation and matrix biology

The RhoGTPases, with RhoA, Cdc42 and Rac being major members, are a group of key ubiquitous proteins present in all eukaryotic organisms that subserve such important functions as cell migration, adhesion and differentiation. The NFκB (nuclear factor κB) is a family of constitutive and inducible transcription factors that through their diverse target genes, play a major role in processes such as cytokine expression, stress regulation, cell division and transformation. Research over the past decade has uncovered new molecular links between the RhoGTPases and the NFκB pathway, with the RhoGTPases playing a positive or negative regulatory role on NFκB activation depending on the context. The RhoA–NFκB interaction has been shown to be important in cytokine-activated NFκB processes, such as those induced by TNFα (tumour necrosis factor α). On the other hand, Rac is important for activating the NFκB response downstream of integrin activation, such as after phagocytosis. Specific residues of Rac1 are important for triggering NFκB activation, and mutations do obliterate this response. Other upstream triggers of the RhoGTPase–NFκB interactions include the suppressive p120 catenin, with implications for skin inflammation. The networks described here are not only important areas for further research, but are also significant for discovery of targets for translational medicine.

Rad GTPase inhibits the NFκB pathway through interacting with RelA/p65 to impede its DNA binding and target gene transactivation

Rad is a Ras-related small GTPase shown to inhibit cancer cell migration, and its expression is frequently lost in lung cancer cells. Here we provide evidence that Rad can negatively regulate the NFκB pathway. Overexpressing Rad in cells lowered both the basal and TNFα-stimulated transcriptional activity of NFκB. Compared with control cells, Rad-overexpressing cells displayed more cytoplasmic distribution of the NFκB subunit RelA/p65, while Rad-knockdown cells had higher levels of nuclear RelA/p65. Depleting Rad did not affect the kinetics of TNFα-induced IκB degradation, suggesting that Rad-mediated regulation of NFκB was through an IκB-independent mechanism. Expression of a nucleus-localized mutant Rad was sufficient to inhibit the NFκB transcriptional activity, whereas expressing the scaffolding protein 14-3-3γ to retain Rad in the cytoplasm alleviated the suppressive effect of Rad on NFκB. GST pull-down assays showed that Rad could directly bind to RelA/p65, and co-immunoprecipitation demonstrated that the Rad-p65 interaction primarily occurred in the nucleus. Adding Rad-containing nuclear extracts or purified GST-Rad in the electrophoretic mobility shift assays dose-dependently decreased the binding of RelA/p65 to an oligonucleotide probe containing the NFκB response element, suggesting that Rad may directly impede the interaction between RelA/p65 and DNA. Rad depletion altered the expression of an array of NFκB target genes, including upregulating MMP9. Knockdown of Rad expression in cells increased both basal and TNFα-stimulated MMP9 activities and cell invasion. Collectively, our results disclose a novel role of nuclear Rad in inhibiting the NFκB pathway function.

Linking phenotype to kinase: identification of a novel benzoxaborole hinge-binding motif for kinase inhibition and development of high-potency rho kinase inhibitors

Benzoxaboroles are a novel class of drug-like compounds that have been rich sources of novel inhibitors for various enzymes and of new drugs. While examining benzoxaborole activity in phenotypic screens, our attention was attracted by the (aminomethylphenoxy)benzoxaborole family, which potently inhibited Toll-like receptor-stimulated cytokine secretion from leukocytes. After considering their structure-activity relationships and the central role of kinases in leukocyte biology, we performed a kinome-wide screen to investigate the members of the (aminomethylphenoxy)benzoxaborole family. This technique identified Rho-activated kinase (ROCK) as a target. We showed competitive behavior, with respect to ATP, and then determined the ROCK2-drug cocrystal structure. The drug occupies the ATP site in which the oxaborole moiety provides hydrogen bond donors and acceptors to the hinge, and the aminomethyl group interacts with the magnesium/ATP-interacting aspartic acid common to protein kinases. The series exhibits excellent selectivity against most of the kinome, with greater than 15-fold selectivity against the next best member of the AGC protein kinase subfamily. Medicinal chemistry efforts with structure-based design resulted in a compound with a Ki of 170 nM. Cellular studies revealed strong enzyme inhibition rank correlation with suppression of intracellular phosphorylation of a ROCK substrate. The biochemical potencies of these compounds also translated to functional activity, causing smooth muscle relaxation in rat aorta and guinea pig trachea. The series exhibited oral availability and one member reduced rat blood pressure, consistent with ROCK's role in smooth muscle contraction. Thus, the benzoxaborole moiety represents a novel hinge-binding kinase scaffold that may have potential for therapeutic use.

Thrombin selectively engages LIM kinase 1 and slingshot-1L phosphatase to regulate NF-κB activation and endothelial cell inflammation

Endothelial cell (EC) inflammation is a central event in the pathogenesis of many pulmonary diseases such as acute lung injury and its more severe form acute respiratory distress syndrome. Alterations in actin cytoskeleton are shown to be crucial for NF-κB regulation and EC inflammation. Previously, we have described a role of actin binding protein cofilin in mediating cytoskeletal alterations essential for NF-κB activation and EC inflammation. The present study describes a dynamic mechanism in which LIM kinase 1 (LIMK1), a cofilin kinase, and slingshot-1Long (SSH-1L), a cofilin phosphatase, are engaged by procoagulant and proinflammatory mediator thrombin to regulate these responses. Our data show that knockdown of LIMK1 destabilizes whereas knockdown of SSH-1L stabilizes the actin filaments through modulation of cofilin phosphorylation; however, in either case thrombin-induced NF-κB activity and expression of its target genes (ICAM-1 and VCAM-1) is inhibited. Further mechanistic analyses reveal that knockdown of LIMK1 or SSH-1L each attenuates nuclear translocation and thereby DNA binding of RelA/p65. In addition, LIMK1 or SSH-1L depletion inhibited RelA/p65 phosphorylation at Ser(536), a critical event conferring transcriptional competency to the bound NF-κB. However, unlike SSH-1L, LIMK1 knockdown also impairs the release of RelA/p65 by blocking IKKβ-dependent phosphorylation/degradation of IκBα. Interestingly, LIMK1 or SSH-1L depletion failed to inhibit TNF-α-induced RelA/p65 nuclear translocation and proinflammatory gene expression. Thus this study provides evidence for a novel role of LIMK1 and SSH-1L in selectively regulating EC inflammation associated with intravascular coagulation.

Critical role of sphingosine-1-phosphate receptor 2 (S1PR2) in acute vascular inflammation

The endothelium, as the interface between blood and all tissues, plays a critical role in inflammation. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid, highly abundant in plasma, that potently regulates endothelial responses through interaction with its receptors (S1PRs). Here, we studied the role of S1PR2 in the regulation of the proadhesion and proinflammatory phenotype of the endothelium. By using genetic approaches and a S1PR2-specific antagonist (JTE013), we found that S1PR2 plays a key role in the permeability and inflammatory responses of the vascular endothelium during endotoxemia. Experiments with bone marrow chimeras (S1pr2(+/+) → S1pr2(+/+), S1pr2(+/+) → S1pr2(-/-), and S1pr2(-/-) → S1pr2(+/+)) indicate the critical role of S1PR2 in the stromal compartment, in the regulation of vascular permeability and vascular inflammation. In vitro, JTE013 potently inhibited tumor necrosis factor α-induced endothelial inflammation. Finally, we provide detailed mechanisms on the downstream signaling of S1PR2 in vascular inflammation that include the activation of the stress-activated protein kinase pathway that, together with the Rho-kinase nuclear factor kappa B pathway (NF-kB), are required for S1PR2-mediated endothelial inflammatory responses. Taken together, our data indicate that S1PR2 is a key regulator of the proinflammatory phenotype of the endothelium and identify S1PR2 as a novel therapeutic target for vascular disorders.