Regulation of endothelial permeability and transendothelial migration of cancer cells by tropomyosin-1 phosphorylation

Development of a biofabricated 3Din vitrovessel model for investigating transendothelial migration in stem cell therapy

Systemic stem cell therapies hold promise for treating severe diseases, but their efficiency is hampered by limited migration of injected stem cells across vascular endothelium towards diseased tissues. Understanding transendothelial migration is crucial for improving therapy outcomes. We propose a novel 3Din vitrovessel model that aids to unravel these mechanisms and thereby facilitates stem cell therapy development. Our model simulates inflammation through cytokine diffusion from the tissue site into the vessel. It consists of a biofabricated vessel embedded in a fibrin hydrogel, mimicking arterial wall composition with smooth muscle cells and fibroblasts. The perfusable channel is lined with a functional endothelium which expresses vascular endothelial cadherin, provides an active barrier function, aligns with flow direction and is reconstructed byin situtwo-photon-microscopy. Inflammatory cytokine release (tumor necrosis factorα, stromal-derived factor (1) is demonstrated in both a transwell assay and the 3D model. In proof-of-principle experiments, mesoangioblasts, known as a promising candidate for a stem cell therapy against muscular dystrophies, are injected into the vessel model, showing shear-resistant endothelial adhesion under capillary-like flow conditions. Our 3Din vitromodel offers significant potential to study transendothelial migration mechanisms of stem cells, facilitating the development of improved stem cell therapies.

Alterations in the expression pattern of RBC membrane associated proteins (RMAPs) in whole body γ-irradiated Sprague Dawley rats

PURPOSE

Peripheral blood serum/plasma proteins are frequently studied for their potential use as radiation exposure biomarkers. Here we report RBC membrane associated proteins (RMAPs), which show alterations in expression level following whole-body γ-irradiation of rats at sub-lethal/lethal doses.

MATERIALS AND METHODS

RBCs from peripheral blood of Sprague Dawley rats were segregated using the Ficoll-Hypaque method, and membrane fractions were hypotonically isolated at various time points (6 h, 24 h, 48 h) after γ-irradiation at 2 Gy, 5 Gy, and 7.5 Gy doses. Following purification of proteins from these fractions, two-dimensional electrophoresis (2-DE) was carried out. Treatment induced differentially expressed protein spots (≥2 fold increase/decrease) were picked up, trypsinized, and identified using LC-MS/MS analysis. Western immunoblots using protein specific antibodies were used to confirm the results. Gene ontology and interactions of these proteins were also studied.

RESULTS

From a number of differentially expressed radiation-responsive 2-DE protein spots detected, eight were identified unequivocally using LC-MS/MS. Out of these, actin, cytoplasmic 1 (ACTB) showed detectable yet insignificant variation (<50%) in expression. In contrast, peroxiredoxin-2 (PRDX2) and 26S proteasome regulatory subunit RPN11 (PSMD14) were the two most prominently over-expressed proteins. Five more proteins, namely tropomyosin alpha-3 chain (TPM3), exosome component 6 (EXOSC6), isoform 4 of tropomyosin alpha-1 chain (TPM1), serum albumin (ALB), and the 55 kDa erythrocyte membrane protein (P55) showed distinct alteration in their expression at different time-points and doses. ALB, EXOSC6, and PSMD14 were the most responsive at 2 Gy, albeit at different time-points. While EXOSC6 and PSMD14 showed maximum over-expression (5-12 fold) at 6 h post-irradiation, ALB expression increased progressively (4 up to 7 fold) from 6 h to 48 h. TPM1 showed over-expression (2-3 fold) at all doses and time-points tested. TPM3 showed a dose-dependent response at all time-points studied; with no variation at 2 Gy, ∼2 fold increase at 5 Gy, and 3-6 fold at the highest dose used (7.5 Gy). The p55 protein was over-expressed (∼2.5 fold) only transiently at 24 h following the lethal (7.5 Gy) dose.

CONCLUSION

This is the first study to report γ-radiation induced alterations in the RBC membrane associated proteins. We are further evaluating the potential of these proteins as radiation biomarkers. Due to the abundance and easy use of RBCs, this approach can prove very useful for detecting ionizing radiation exposure.

Interaction of Drug-Sensitive and -Resistant Human Melanoma Cells with HUVEC Cells: A Label-Free Cell-Based Impedance Study

Cancer cell extravasation is a crucial step in cancer metastasis. However, many of the mechanisms involved in this process are only now being elucidated. Thus, in the present study we analysed the trans-endothelial invasion of melanoma cells by a high throughput label-free cell impedance assay applied to transwell chamber invasion assay. This technique monitors and quantifies in real-time the invasion of endothelial cells by malignant tumour cells, for a long time, avoiding artefacts due to preparation of the end point measurements. Results obtained by impedance analysis were compared with endpoint measurements. In this study, we used human melanoma M14 wild type (WT) cells and their drug resistant counterparts, M14 multidrug resistant (ADR) melanoma cells, selected by prolonged exposure to doxorubicin (DOX). Tumour cells were co-cultured with monolayers of human umbilical vein endothelial cells (HUVEC). Results herein reported demonstrated that: (i) the trans-endothelial migration of resistant melanoma cells was faster than sensitive ones; (ii) the endothelial cells appeared to be strongly affected by the transmigration of melanoma cells which showed the ability to degrade their cytoplasm; (iii) resistant cells preferentially adopted the transcellular invasion vs. the paracellular one; (iv) the endothelial damage mediated by tumour metalloproteinases seemed to be reversible.

Emerging Role of Plant-Based Dietary Components in Post-Translational Modifications Associated with Colorectal Cancer

Colorectal cancer (CRC) is one of the most common cancers worldwide. Its main modifiable risk factors are diet, alcohol consumption, and smoking. Thus, the right approach through lifestyle changes may lead to its prevention. In fact, some natural dietary components have exhibited chemopreventive activity through modulation of cellular processes involved in CRC development. Although cancer is a multi-factorial process, the study of post-translational modifications (PTMs) of proteins associated with CRC has recently gained interest, as inappropriate modification is closely related to the activation of cell signalling pathways involved in carcinogenesis. Therefore, this review aimed to collect the main PTMs associated with CRC, analyse the relationship between different proteins that are susceptible to inappropriate PTMs, and review the available scientific literature on the role of plant-based dietary compounds in modulating CRC-associated PTMs. In summary, this review suggested that some plant-based dietary components such as phenols, flavonoids, lignans, terpenoids, and alkaloids may be able to correct the inappropriate PTMs associated with CRC and promote apoptosis in tumour cells.

Identification of hub genes and regulatory networks in histologically unstable carotid atherosclerotic plaque by bioinformatics analysis

Objective

This study identified underlying genetic molecules associated with histologically unstable carotid atherosclerotic plaques through bioinformatics analysis that may be potential biomarkers and therapeutic targets.

Methods

Three transcriptome datasets (GSE41571, GSE120521 and E-MTAB-2055) and one non-coding RNA dataset (GSE111794) that met histological grouping criteria of unstable plaque were downloaded. The common differentially expressed genes (co-DEGs) of unstable plaques identified from three mRNA datasets were annotated by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomics (KEGG). A protein–protein interaction (PPI) network was constructed to present the interaction between co-DEGs and screen out hub genes. MiRNet database and GSE111794 dataset were used to identify the miRNAs targeting hub genes. Associated transcription factors (TFs) and drugs were also predicted. These predicted results were used to construct miRNA/TFs-hub gene and drug-hub gene regulatory networks.

Results

A total of 105 co-DEGs were identified, including 42 up-regulated genes and 63 down-regulated genes, which were mainly enriched in collagen-containing extracellular matrix, focal adhesion, actin filament bundle, chemokine signaling pathway and regulates of actin cytoskeleton. Ten hub genes (up-regulated: HCK, C1QC, CD14, FCER1G, LCP1 and RAC2; down-regulated: TPM1, MYH10, PLS3 and FMOD) were screened. HCK and RAC2 were involved in chemokine signaling pathway, MYH10 and RAC2 were involved in regulation of actin cytoskeleton. We also predicted 12 miRNAs, top5 TFs and 25 drugs targeting hub genes. In the miRNA/TF-hub gene regulatory network, PLS3 was the most connected hub genes and was targeted by six miRNAs and all five screened TFs. In the drug-hub gene regulatory network, HCK was targeted by 20 drugs including 10 inhibitors.

Conclusions

We screened 10 hub genes and predicted miRNAs and TFs targeting them. These molecules may play a crucial role in the progression of histologically unstable carotid plaques and serve as potential biomarkers and therapeutic targets.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01257-1.

A reciprocal feedback of miR-548ac/YB-1/Snail induces EndMT of HUVECs during acidity microenvironment

Background

Researches indicated the process of Endothelial-Mesenchymal-Transition (EndMT) of vascular endothelial cells (ECs) was critically involved in the progression of tumor. ECs demonstrated functional and phenotypic heterogeneity when located under different microenvironments. The extracellular pH of tumor tissues was acidic compared to that of normal tissues. However, there was still unclear whether the acidic microenvironment affected the EndMT of vascular ECs.

Methods

Human Umbilical Vein Endothelial Cell (HUVECs) was cultured under the normal or acidic medium to evaluate the alteration of morphology, migration, permeability, and EndMT markers. Microarray assay was adopted to analyze the differential expression of miRNAs in the acidity-treated HUVECs. Gain- and loss- of function experiments were performed to evaluate the functional role of miRNA-548ac on acidity-induced EndMT of HUVECs. Luciferase reporter and Chromatin-immunoprecipitation assays were conducted to assess the downstream pathway of miRNA-548ac in acidity-induced EndMT of HUVECs.

Results

Our results showed that HUVECs demonstrated mesenchymal transition under acidic conditions with the increase of migration, permeability, and expression of α-SMA and Vimentin, but the expression of vascular endothelial cadherin (VE-cadherin) and CD31 were reduced. In addition, the acidity-treated HUVECs remarkably facilitated the transmigration of pancreatic cancer cells. The expression of miRNA-548ac was significantly decreased in the acidity-treated HUVECs. Moreover, overexpression of miR-548ac inhibited the EndMT of HUVECs and consequently impeded the transmigration of pancreatic cancer cells. The miR-548ac inhibited the expression of YB-1 by binding to the 3’UTR of its mRNA, and YB-1 promoted the translation of Snail which was a critical regulator of EndMT. What’s more, Snail transcriptionally inhibited the expression of miR-548ac through binding to the promoter of its host gene.

Conclusions

Our data implicated that the acidic microenvironment promoted the EndMT of HUVECs by the miR-548ac/YB-1/Snail axis, which could contribute to the metastasis of pancreatic cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02388-8.

HA and HS Changes in Endothelial Inflammatory Activation

Cardiovascular diseases are a group of disorders caused by the presence of a combination of risk factors, such as tobacco use, unhealthy diet and obesity, physical inactivity, etc., which cause the modification of the composition of the vessel’s matrix and lead to the alteration of blood flow, matched with an inflammation condition. Nevertheless, it is not clear if the inflammation is a permissive condition or a consequent one. In order to investigate the effect of inflammation on the onset of vascular disease, we treated endothelial cells with the cytokine TNF-α that is increased in obese patients and is reported to induce cardiometabolic diseases. The inflammation induced a large change in the extracellular matrix, increasing the pericellular hyaluronan and altering the heparan sulfate Syndecans sets, which seems to be related to layer permeability but does not influence cell proliferation or migration nor induce blood cell recruitment or activation.

RBM3 Increases Cell Survival but Disrupts Tight Junction of Microvascular Endothelial Cells in Acute Lung Injury

BACKGROUND

RNA-binding motif protein 3 (RBM3) is an important cold shock protein, which also responds to hypothermia or hypoxia. RBM3 is involved into multiple physiologic processes, such as promoting cell survival. However, its expression and function in acute lung injury (ALI) have not been reported.

METHODS

A mouse ALI model was established by lipopolysaccharides (LPS) treatment. The RBM3 and cold inducible RNA-binding protein mRNA levels were examined by RT-qPCR, and MMP9 mRNA stability was determined by actinomycin D assay. RBM3 and MMP9 mRNA was tested by RNA immunoprecipitation (RIP assay). RBM3 overexpression or silent stable cell lines were established using recombinant lentivirus and subsequently used for cell survival and tight junction measurements.

RESULTS

In this study, we found that RBM3, rather than cold inducible RNA-binding protein, was upregulated in lung tissue of ALI mice. RBM3 was increased in human pulmonary microvascular endothelial cells (HPMVECs) in response to LPS treatment, which is modulated by the NF-κB signaling pathway. Furthermore, RBM3 could reduce cell apoptosis induced by LPS, probably through suppressing p53 expression. Because increased permeability of HPMVECs leads to pulmonary edema in ALI, we subsequently examined the effect of RBM3 on cell tight junctions. Unexpectedly, RBM3 decreased the expression of tight junction protein zonula occludens-1 and increased cell permeability, and RBM3 overexpression increased MMP9 mRNA stability. Furthermore, RIP assay confirmed the interaction between RBM3 and MMP9 mRNA, possibly explaining the contribution of RBM3 to increase cell permeability.

CONCLUSIONS

RBM3 seems to act as a "double-edged sword" in ALI, that RBM3 alleviates cell apoptosis but increases HPMVEC permeability in ALI.

Further Investigation into the Biochemical Effects of Phosphorylation of Tropomyosin Tpm1.1(α). Serine-283 Is in Communication with the Midregion

The phosphorylated and unphosphorylated forms of tropomyosin Tpm1.1(α) are prepared from adult rabbit heart and compared biochemically. Electrophoresis confirms the high level of enrichment of the chromatography fractions and is consistent with a single site of phosphorylation. Covalently bound phosphate groups at position 283 of Tpm1.1(α) increase the rate of digestion at Leu-169, suggestive of a conformational rearrangement that extends to the midregion. Such a rearrangement, which is supported by ellipticity measurements between 25 and 42 °C, is consistent with a phosphorylation-mediated tightening of the interaction between various myofilament components. In a nonradioactive, co-sedimentation assay [30 mM KCl, 1 mM Mg(II), and 4 °C], phosphorylated Tpm1.1(α) displays a higher affinity for F-actin compared to that of the unphosphorylated control (K_d, 0.16 μM vs 0.26 μM). Phosphorylation decreases the concentration of thin filaments (pCa 4 plus ATP) required to attain a half-maximal rate of release of product from a pre-power stroke complex [myosin-S1-2-deoxy-3-O-(N-methylanthraniloyl)ADP-P_i], as investigated by double-mixing stopped-flow fluorescence, suggestive of a change in the proportion of active (turned on) and inactive (turned off) conformers, but similar maximum rates of product release are observed with either type of reconstituted thin filament. Phosphorylated thin filaments (pCa 4 and 8) display a higher affinity for myosin-S1(ADP) versus the control scenario without affecting isotherm steepness. Specific activities of ATP and Tpm1.1(α) are determined during an in vitro incubation of rat cardiac tissue [12 day-old, 50% phosphorylated Tpm1.1(α)] with [³²P]orthophosphate. The incorporation of an isotope into tropomyosin lags behind that of ATP by a factor of approximately 10, indicating that transfer is a comparatively slow process.

Endothelial cells and organ function: applications and implications of understanding unique and reciprocal remodelling

The microvasculature is a heterogeneous, dynamic and versatile component of the systemic circulation, with a unique ability to locally self-regulate and to respond to organ demand and environmental stimuli. Endothelial cells from different organs display considerable variation, but it is currently unclear to what extent functional properties of organ-specific endothelial cells are intrinsic, acquired and/or reprogrammable. Vascular function is a fundamental pillar of homeostasis, and dysfunction results in systemic consequences for the organism. Additionally, vascular failure can occur downstream of organ disease or environmental stress, often driving an exacerbation of symptoms and pathologies originally independent of the local circulation. The understanding of the molecular mechanisms underlying endothelial physiology and metabolism holds the promise to inform and improve diagnosis, prognosis and treatment options for a myriad of conditions as unrelated as cancer, neurodegeneration or pulmonary hypertension, and likely everything in between, if we consider that also treatments for such conditions are primarily distributed via the bloodstream. However, studying endothelial function has its challenges: the origin, isolation, culture conditions and preconditioning stimuli make this an extremely variable cell type to study and difficult to source. Animal models exist but are neither trivial to generate, nor necessarily adequately translatable to human disease. In this article, we aim to illustrate the breadth of microvascular functions in different environments, highlighting current and pioneering studies that have advanced our insight into the importance of the integrity of this tissue, as well as the limitations posed by its heterogeneity and plasticity.

6-Gingerol stabilized the p-VEGFR2/VE-cadherin/β-catenin/actin complex promotes microvessel normalization and suppresses tumor progression

BACKGROUND

Anti-angiogenic therapies demonstrate anti-tumor effects by decreasing blood supply to tumors and inhibiting tumor growth. However, anti-angiogenic therapy may leads to changes in tumor microenvironment and increased invasiveness of tumor cells, which in turn promotes distant metastasis and increased drug resistance.

METHODS

The CO-IP assays, N-STORM and cytoskeleton analysis were used to confirm the mechanism that p-VEGFR2/VE-cadherin/β-catenin/actin complex regulates vascular remodeling and improves the tumor microenvironment. 6-gingerol (6G), the major bioactive component in ginger, stabilized this complex by enhancing the binding of VEGFa to VEGFR2 with non-pathway dependent. Biacore, pull down and molecular docking were employed to confirm the interaction between 6G and VEGFR2 and enhancement of VEGFa binding to VEGFR2.

RESULTS

Here, we report that microvascular structural entropy (MSE) may be a prognostic factor in several tumor types and have potential as a biomarker in the clinic. 6G regulates the structural organization of the microvascular bed to decrease MSE via the p-VEGFR2/VE-cadherin/β-catenin/actin complex and inhibit tumor progression. 6G promotes the normalization of tumor vessels, improves the tumor microenvironment and decreases MSE, facilitating the delivery of chemotherapeutic agents into the tumor core and thereby reducing tumor growth and metastasis.

CONCLUSIONS

This study demonstrated the importance of vascular normalization in tumor therapy and elucidated the mechanism of action of ginger, a medicinal compound that has been used in China since ancient times.

Biofabrication strategies for creating microvascular complexity

Design and fabrication of effective biomimetic vasculatures constitutes a relevant and yet unsolved challenge, lying at the heart of tissue repair and regeneration strategies. Even if cell growth is achieved in 3D tissue scaffolds or advanced implants, tissue viability inevitably requires vascularization, as diffusion can only transport nutrients and eliminate debris within a few hundred microns. This engineered vasculature may need to mimic the intricate branching geometry of native microvasculature, referred to herein as vascular complexity, to efficiently deliver blood and recreate critical interactions between the vascular and perivascular cells as well as parenchymal tissues. This review first describes the importance of vascular complexity in labs- and organs-on-chips, the biomechanical and biochemical signals needed to create and maintain a complex vasculature, and the limitations of current 2D, 2.5D, and 3D culture systems in recreating vascular complexity. We then critically review available strategies for design and biofabrication of complex vasculatures in cell culture platforms, labs- and organs-on-chips, and tissue engineering scaffolds, highlighting their advantages and disadvantages. Finally, challenges and future directions are outlined with the hope of inspiring researchers to create the reliable, efficient and sustainable tools needed for design and biofabrication of complex vasculatures.

Vulpinic acid, a lichen metabolite, emerges as a potential drug candidate in the therapy of oxidative stress–related diseases, such as atherosclerosis

Vulpinic acid, a lichen compound, has been shown to have many beneficial effects and its medicinal value increases day by day. As in atherosclerosis, endothelial damage is the basis of many diseases. The aim of this study is to investigate the effects of vulpinic acid against oxidative stress damage induced by hydrogen peroxide (H2O2) in endothelial cells. In order to find the IC50 of H2O2 and the protective dose of vulpinic acid, methyl thiazolyldiphenyl tetrazolium bromide (MTT) assays were performed. The amount of reactive oxygen species (ROS) induced by H2O2 and the protective effects of vulpinic acid against ROS were examined by fluorometric DCF-DA kit. The effects of H2O2 and vulpinic acid on actin filaments were determined by tetramethyl rhodamine (TRITC)-phalloidin fluorescence staining. Expression of Tie2 proteins was immunocytochemically analyzed in H2O2- and vulpinic acid-treated cells. After 24 h, the IC50 was found to be 215 μM in HUVECs treated with H2O2. The most effective dose of vulpinic acid against H2O2-associated damage was found to be 15 μM. Vulpinic acid pretreatment was shown to reduce H2O2-induced ROS production significantly ( p < 0.05). It was shown that 215 μM of H2O2 caused actin fragmentation, cell shrinkage, and decrease in actin florescence intensity while vulpinic acid protected the cells from these damages. It was found that Tie2 immunoreactivity was decreased in H2O2-treated groups and vulpinic acid pretreatment reduced the expression of this protein. In conclusion, vulpinic acid decreases H2O2-induced oxidative stress and oxidative stress–related damages in HUVECs. It may be drug candidate in the therapy of atherosclerosis.

Stress phase angle regulates differentiation of human adipose-derived stem cells toward endothelial phenotype

Endothelial cells are subjected to cyclic shear by pulsatile blood flow and pressures due to circumferential stresses. Although most of the researches on this topic have considered the effects of these two biomechanical forces separately or concurrently, few studies have noticed the interaction of these cyclic loadings on endothelial behavior. Negative temporal stress phase angle, defined by the phase lag between cyclic shear and tensile stresses, is an established parameter which is known to have substantial effects on blood vessel remodeling and progression of some serious cardiovascular diseases. In this research, intermittent shear and tensile stresses with different stress phase angle values were applied on human adipose stem cells (ASC). The expression level of three major endothelial-specific genes, elastic modulus of cells and cytoskeleton actin structure of cells were studied and compared among control and three test groups subjected to stress phase angle values at 0°, - 45°, and - 90°. Mechanical properties of ASCs were determined by atomic force microscopy and actin fiber structure was visualized by confocal imaging through Phalloidin staining. Results described a decrease in expression of FLK-1 and VE-cadherin and rise of vWF marker expression in case of higher negative stress phase angles. The Young's moduli of cells were significantly higher and cytoskeletal actin structure was more organized with higher thickness for all test samples subjected to combined stresses; however, these features were less magnificent for applied stress phase angles with higher negative values. The results confirmed significant effects of SPA on endothelial differentiation of mesenchymal stem cells.

Fluorescence tumor imaging by i.v. administered indocyanine green in a mouse model of colitis-associated colon cancer

Fluorescence tumor imaging using exogenous fluorescent tumor‐targeting agents has potential to improve early tumor detection. The fluorescent contrast agent indocyanine green (ICG) is used in medical diagnostics. The aim of the present study is to investigate the tumor imaging capability and the imaging mechanism of i.v. administered ICG in a mouse model of colitis‐associated colon cancer. To do this, an azoxymethane/dextran sodium sulfate‐induced colon cancer mouse model was used. Ex vivo imaging experiments were carried out 1 hour after i.v. injection of ICG. The ICG fluorescence was observed in the colon tumor tissues, with sufficient tumor to normal tissue ratio, correlating with tumor malignancy. In the tumor tissues, ICG fluorescence was localized in the vascular interstitial tissue. Immunofluorescence microscopy revealed that tumor cells formed tight junctions normally, suggesting an inability of tumor cellular uptake of ICG. In contrast, tumor tissues increased the CD31‐immunoreactive endothelial cell area, and accumulated stromal cells immunoreactive for COX‐2 and tumor cell population immunoreactive for inducible nitric oxide synthase. In vivo vascular permeability assay revealed that prostaglandin E₂ promoted the endothelial cell permeability of ICG. In conclusion, our data indicated that fluorescence contrast‐enhanced imaging following i.v. administered ICG can be applied to the detection of colon tumors in a mouse colitis‐associated colon cancer model. The tumor tissue preference of ICG in the present model can be attributed to the enhanced vascular leakage of ICG involving inflammatory mediators, such as COX‐2 and inducible nitric oxide synthase, in conjunction with increased tumor vascularity.

Proteomic analysis and comparison of intra‑ and extracranial cerebral atherosclerosis responses to hyperlipidemia in rabbits

The present study aimed to investigate protein expression levels of intra‑ and extracranial atherosclerosis in rabbits following administration of a high‑fat diet. Rabbits were randomly divided into control (group A; n=9) and high‑fat diet (group B; n=9) groups. At week 12, tissues were sectioned from the common carotid artery (CCA) and middle cerebral artery (MCA). Pathological analysis was performed. Differential protein expression levels were examined by 2‑D gel electrophoresis (2‑DE) and mass spectrometry (MS) analysis and validated by western blotting. Serum lipid levels, the intima‑media thickness (IMT) and degree of atherosclerosis of the CCA and MCA were increased at week 12 in the high‑fat diet group compared with rabbits that received a normal diet. 2‑DE and MS analysis of the protein extracted from CCA and MCA detected >439 different proteins; the expression of 25 proteins was altered, and 8 proteins [albumin A chain, tropomyosin α‑1 chain (TPM1), heat shock protein 70 (HSP70), α‑smooth muscle actin, β‑galactose binding agglutinin, TPM4 isoform 2, cell keratin 9, single octylic acid glyceride β‑2) demonstrated significant alterations in expression levels. Due to limited antibody sources, only three differentially expressed proteins (TPM1, HSP70 and α‑smooth muscle actin) were examined by western blotting. The results of our previous study demonstrated that hyperlipidemia affected the IMT of intracranial and extracranial cerebral arteries. In the present study, protein expression levels of TPM1 and α‑smooth muscle actin from extracranial cerebral arteries were significantly increased compared with intracranial cerebral arteries; however, protein expression levels of HSP70 from intracranial cerebral arteries was increased compared with extracranial cerebral arteries. The differences may be closely associated with cell proliferation and metastasis, and oxidoreduction, in intra‑ and extracranial cerebral atherosclerosis. HSP70 may have protective properties against atherosclerosis via underlying anti‑inflammatory mechanisms, furthermore, differential protein expression levels (TPM1, HSP70 and α‑smooth muscle actin) between intra‑ and extracranial cerebral arteries may facilitate the identification of novel biological markers for the diagnosis and treatment of cerebral arteriosclerosis.

The p38 pathway, a major pleiotropic cascade that transduces stress and metastatic signals in endothelial cells

By gating the traffic of molecules and cells across the vessel wall, endothelial cells play a central role in regulating cardiovascular functions and systemic homeostasis and in modulating pathophysiological processes such as inflammation and immunity. Accordingly, the loss of endothelial cell integrity is associated with pathological disorders that include atherosclerosis and cancer. The p38 mitogen-activated protein kinase (MAPK) cascades are major signaling pathways that regulate several functions of endothelial cells in response to exogenous and endogenous stimuli including growth factors, stress and cytokines. The p38 MAPK family contains four isoforms p38α, p38β, p38γ and p38δ that are encoded by four different genes. They are all widely expressed although to different levels in almost all human tissues. p38α/MAPK14, that is ubiquitously expressed is the prototype member of the family and is referred here as p38. It regulates the production of inflammatory mediators, and controls cell proliferation, differentiation, migration and survival. Its activation in endothelial cells leads to actin remodeling, angiogenesis, DNA damage response and thereby has major impact on cardiovascular homeostasis, and on cancer progression. In this manuscript, we review the biology of p38 in regulating endothelial functions especially in response to oxidative stress and during the metastatic process.

Visualization of endothelial barrier damage prior to formation of atherosclerotic plaques

En-face fat staining is frequently used to visualize atherosclerotic lesions. This method, however, is not suitable to visualize endothelial barrier damage prior to microscopically detectable morphological alterations of the arterial wall such as sub-endothelial lipid deposition. To enable the investigation of early endothelial barrier damage and in particular the initial steps of atherosclerosis, a new method has to fulfill three requirements: (i) easy and fast to perform, (ii) low cost of applicability without requirement for highly sophisticated technical equipment, and (iii) reliable reproducibility of valid results. To this end, we used intracardial Evans blue dye injection after washout of blood and measured dye deposition within the aortic wall as a parameter of endothelial barrier leakiness, which is recognized as one of the earliest signs of atherosclerotic plaque formation. These analyses were performed in ApoE ^-/-, LDL receptor ^-/- and Cc1 ^-/- mouse models which have been reported to develop aortic plaques with or without high cholesterol diet. Our data show that sub-endothelial dye deposition is a reliable and reproducible readout parameter to assess endothelial barrier damage. Along these lines, measurements of aortic intima areas with Evans blue deposition in relation to total intima circumference enabled quantitative assessments of the results. Our technique enables the imaging of endothelial barrier damage prior to detectable aortic lipid deposition and plaque development. Thus, it will facilitate the detection of the initial vascular pathogenetic processes that lead to cardiovascular diseases. It will also enable the testing of new drugs and therapeutic procedures to prevent these disorders.

Protective effect of prostacyclin against pre-cardiac edema caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin and a thromboxane receptor agonist in developing zebrafish

The role of prostaglandin pathways has been suggested in some toxicological responses to dioxins. Cyclooxygenase type 2b (COX2b), thromboxane synthase, and the thromboxane receptor (TP) pathway have been implicated in mediating 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced pre-cardiac edema in developing zebrafish at 55 h post fertilization (hpf). Pre-cardiac edema refers to edema located in a small cavity between the heart and body wall of zebrafish eleutheroembryos. In the present study, we assessed the role of prostacyclin, which counteracts some biological effects of thromboxane, in TCDD-induced pre-cardiac edema. Pre-cardiac edema induced by TCDD exposure (0.5 and 1 ppb) beginning at 24 hpf was markedly inhibited by exposure to beraprost (5 and 10 μM), a prostacyclin receptor (IP) agonist, beginning at 33 hpf. The preventive effect of beraprost was reduced by exposure to CAY10441 (10 μM), an IP antagonist starting at 33 hpf. Knockdowns of the IP receptor (IP-KD) with two different morpholinos caused edema by themselves and enhanced pre-cardiac edema caused by the low concentration of TCDD (0.5 ppb). On the other hand, short exposure beginning at 48 hpf to U46619 (7.5-30 μM), a thromboxane receptor agonist caused pre-cardiac edema, which was inhibited by exposure beginning at 48 hpf to both ICI-192,605 (24 μM), a TP antagonist, and beraprost. Expression of prostacyclin synthase was increased from fertilization, plateaued by 48 hpf, and was maintained until at least 96 hpf. Overall, the results demonstrate a preventive effect of prostacyclin on TCDD-induced pre-cardiac edema in developing zebrafish.

Angiopoietin-like 4: A double-edged sword in atherosclerosis and ischemic stroke?

Ischemic stroke is one of the leading causes of death in the world, and thus is a major public health concern. Atherosclerosis, also known as atherogenesis, is a crucial risk factor for cerebral ischemia, yet how it develops remains largely unknown. It has been found, however, that angiopoietin-like protein 4 (ANGPTL4), a protein expressed in vascular endothelial cells, plays a role in the pathophysiology of atherosclerosis and may therefore be involved in ischemic stroke. ANGPTL4 activity is associated with endothelial cell integrity, inflammation, oxidative stress, and lipid metabolism. ANGPTL4 also serves as a potent inhibitor of the lipoprotein lipase, and may inhibit atherogenesis via regulating inflammatory signaling and lipid metabolism. In addition, ANGPTL4 plays a role in the regulation of oxidative stress. However, there currently exists a controversy on the role of ANGPTL4 in endothelial cells. Some studies indicate that ANGPTL4 can protect the integrity of endothelial cells, while others have shown that it can be destructive to the endothelium, thereby leading to the initiation of atherosclerosis. Thus, the effects of ANGPTL4 on development of atherosclerosis and thereby ischemic stroke, are undefined. Further research is needed to better understand ANGPTL4-mediated signaling pathways in endothelial function and to determine its potentials as therapeutic target for atherosclerosis and ischemic stroke.

Recombinant Treponema pallidum protein Tp0965 activates endothelial cells and increases the permeability of endothelial cell monolayer

The recombinant Treponema pallidum protein Tp0965 (rTp0965), one of the many proteins derived from the genome of T. pallidum subsp. pallidum, shows strong immunogenicity and immunoreactivity. In this study, we investigated the effects of rTp0965 on the endothelial barrier. Treatment of human umbilical vein endothelial cells (HUVECs) with rTp0965 resulted in increased levels of ICAM-1, E-selectin, and MCP-1 mRNA and protein expression. These increases contributed to the adhesion and chemataxis of monocytes (THP-1 cells) to HUVECs preincubated with rTp0965. In addition, rTp0965 induced reorganization of F-actin and decreased expression of claudin-1 in HUVECs. Interestingly, inhibition of the RhoA/ROCK signal pathway protected against rTp0965-induced higher endothelial permeability as well as transendothelial migration of monocytes. These data indicate that Tp0965 protein may play an important role in the immunopathogenesis of syphilis.

Carbonic anhydrase activation is associated with worsened pathological remodeling in human ischemic diabetic cardiomyopathy

Background

Diabetes mellitus (DM) has multifactorial detrimental effects on myocardial tissue. Recently, carbonic anhydrases (CAs) have been shown to play a major role in diabetic microangiopathy but their role in the diabetic cardiomyopathy is still unknown.

Methods and Results

We obtained left ventricular samples from patients with DM type 2 (DM‐T2) and nondiabetic (NDM) patients with postinfarct heart failure who were undergoing surgical coronary revascularization. Myocardial levels of CA‐I and CA‐II were 6‐ and 11‐fold higher, respectively, in DM‐T2 versus NDM patients. Elevated CA‐I expression was mainly localized in the cardiac interstitium and endothelial cells. CA‐I induced by high glucose levels hampers endothelial cell permeability and determines endothelial cell apoptosis in vitro. Accordingly, capillary density was significantly lower in the DM‐T2 myocardial samples (mean±SE=2152±146 versus 4545±211/mm²). On the other hand, CA‐II was mainly upregulated in cardiomyocytes. The latter was associated with sodium‐hydrogen exchanger‐1 hyperphosphorylation, exaggerated myocyte hypertrophy (cross‐sectional area 565±34 versus 412±27 μm²), and apoptotic death (830±54 versus 470±34 per 10⁶ myocytes) in DM‐T2 versus NDM patients. CA‐II is activated by high glucose levels and directly induces cardiomyocyte hypertrophy and death in vitro, which are prevented by sodium‐hydrogen exchanger‐1 inhibition. CA‐II was shown to be a direct target for repression by microRNA‐23b, which was downregulated in myocardial samples from DM‐T2 patients. MicroRNA‐23b is regulated by p38 mitogen‐activated protein kinase, and it modulates high‐glucose CA‐II–dependent effects on cardiomyocyte survival in vitro.

Conclusions

Myocardial CA activation is significantly elevated in human diabetic ischemic cardiomyopathy. These data may open new avenues for targeted treatment of diabetic heart failure.

Structure and biomechanics of the endothelial transcellular circumferential invasion array in tumor invasion

Cancer cells breach the endothelium not only through cell-cell junctions but also via individual endothelial cells (ECs), or transcellular invasion. The underlying EC forms a circular structure around the transcellular invasion pore that is dependent on myosin light chain kinase (MLCK) and myosin II regulatory light chain (RLC) phosphorylation. Here we offer mechanistic insights into transcellular invasive array formation amid persistent tensile force from activated EC myosin. Fluorescence recovery after photobleaching (FRAP) experiments, sarcomeric distance measurements using super-resolution microscopy and electron microscopy provide details about the nature of the myosin II invasion array. To probe the relationship between biomechanical forces and the tension required to maintain the curvature of contractile filaments, we targeted individual actin-myosin fibers at the invasion site for photoablation. We showed that adjacent filaments rapidly replace the ablat11ed structures. We propose that the transcellular circumferential invasion array (TCIA) provides the necessary constraint within the EC to blunt the radial compression from the invading cancer cell.

Crossing the endothelial barrier during metastasis

During metastasis, cancer cells disseminate to other parts of the body by entering the bloodstream in a process that is called intravasation. They then extravasate at metastatic sites by attaching to endothelial cells that line blood vessels and crossing the vessel walls of tissues or organs. This Review describes how cancer cells cross the endothelial barrier during extravasation and how different receptors, signalling pathways and circulating cells such as leukocytes and platelets contribute to this process. Identification of the mechanisms that underlie cancer cell extravasation could lead to the development of new therapies to reduce metastasis.