High shear stress suppresses proliferation and migration but promotes apoptosis of endothelial cells co-cultured with vascular smooth muscle cells via down-regulating MAPK pathway

Improvement of cellular pattern organization and clarity through centrifugal force

Rapid and strategic cell placement is necessary for high throughput tissue fabrication. Current adhesive cell patterning systems rely on fluidic shear flow to remove cells outside of the patterned regions, but limitations in washing complexity and uniformity prevent adhesive patterns from being widely applied. Centrifugation is commonly used to study the adhesive strength of cells to various substrates; however, the approach has not been applied to selective cell adhesion systems to create highly organized cell patterns. This study shows centrifugation as a promising method to wash cellular patterns after selective binding of cells to the surface has taken place. After patterning H9C2 cells using biotin-streptavidin as a model adhesive patterning system and washing with centrifugation, there is a significant number of cells removed outside of the patterned areas of the substrate compared to the initial seeding, while there is not a significant number removed from the desired patterned areas. This method is effective in patterning multiple size and linear structures from line widths of 50-200 μm without compromising immediate cell viability below 80%. We also test this procedure on a variety of tube-forming cell lines (MPCs, HUVECs) on various tissue-like surface materials (collagen 1 and Matrigel) with no significant differences in their respective tube formation metrics when the cells were seeded directly on their unconjugated surface versus patterned and washed through centrifugation. This result demonstrates that our patterning and centrifugation system can be adapted to a variety of cell types and substrates to create patterns tailored to many biological applications.

Unveiling the immunomodulatory dance: endothelial cells' function and their role in non-small cell lung cancer

The dynamic interactions between tumor endothelial cells (TECs) and the immune microenvironment play a critical role in the progression of non-small cell lung cancer (NSCLC). In general, endothelial cells exhibit diverse immunomodulatory properties, influencing immune cell recruitment, antigen presentation, and regulation of immune checkpoint expression. Understanding the multifaceted roles of TECs as well as assigning specific functional hallmarks to various TEC phenotypes offer new avenues for targeted development of therapeutic interventions, particularly in the context of advanced immunotherapy and anti-angiogenic treatments. This review provides insights into the complex interplay between TECs and the immune system in NSCLC including discussion of potential optimized therapeutic opportunities.

Development of Pyramidal Microwells for Enhanced Cell Spheroid Formation in a Cell-on-Chip Microfluidic System for Cardiac Differentiation of Mouse Embryonic Stem Cells

Three-dimensional (3D) tissue culture models provide in vivo-like conditions for studying cell physiology. This study aimed to examine the efficiency of pyramidal microwell geometries in microfluidic devices on spheroid formation, cell growth, viability, and differentiation in mouse embryonic stem cells (mESCs). The static culture using the hanging drop (HD) method served as a control. The microfluidic chips were fabricated to have varying pyramidal tip angles, including 66°, 90°, and 106°. From flow simulations, when the tip angle increased, streamline distortion decreased, resulting in more uniform flow and a lower velocity gradient near the spheroids. These findings demonstrate the significant influence of microwell geometry on fluid dynamics. The 90° microwells provide optimal conditions, including uniform flow and reduced shear stress, while maintaining the ability for waste removal, resulting in superior spheroid growth compared to the HD method and other microwell designs. From the experiments, by Day 3, spheroids in the 90° microwells reached approximately 400 µm in diameter which was significantly larger than those in the 66° microwells, 106° microwells, and HD cultures. Brachyury gene expression in the 90° microwells was four times higher than the HD method, indicating enhanced mesodermal differentiation essential for cardiac differentiation. Immunofluorescence staining confirmed cardiomyocyte differentiation. In conclusion, microwell geometry significantly influences 3D cell culture outcomes. The pyramidal microwells with a 90° tip angle proved most effective in promoting spheroid growth and cardiac differentiation of mESC differentiation, providing insights for optimizing microfluidic systems in tissue engineering and regenerative medicine.

Multimodal monitoring of cerebral perfusion in carotid endarterectomy patients: a computational fluid dynamics study

Objective

To evaluate postoperative cerebral perfusion changes and their influencing factors in carotid endarterectomy (CEA) patients by integrating multimodal monitoring methods, including cerebral regional oxygen saturation (rSO2), carotid ultrasound (CU), computed tomographic angiography (CTA), and computed tomographic perfusion imaging (CTP), with computational fluid dynamics (CFD) assessment.

Methods

We conducted a cohort study on patients with internal carotid artery (ICA) stenosis undergoing CEA at our institution. Pre- and postoperative assessments included CU, CTA, CTP, and rSO2 monitoring. Hemodynamic parameters recorded were mean flow velocity (MFV), peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI), rSO2, and cerebral blood flow (CBF). CFD quantified the total pressure (TP), wall shear stress (WSS), wall shear stress ratio (WSSR), and translesional pressure ratio (PR) of the ICA. Pearson correlation was used to analyze factors influencing cerebral perfusion changes. Multivariate logistic regression identified risk factors for cerebral hyperperfusion (CH). The predictive value of multimodal and single-modality monitoring for CH was evaluated using ROC curve analysis.

Results

Fifty-six patients were included, with nine developing postoperative CH. CU showed significant reductions in MFV, PSV, EDV, and RI of the ICA (p < 0.001). Ipsilateral rSO2 increased significantly (p = 0.013), while contralateral rSO2 showed no significant change (p = 0.861). CFD revealed significant decreases in TP, WSS, and WSSR (p < 0.001), along with a significant increase in PR (p < 0.001). Pearson analysis indicated that change rate of CBF (ΔCBF) positively correlated with ΔPR and ΔrSO2, and negatively correlated with ΔTP, ΔWSS, and Δ WSSR. Multivariate logistic regression identified preoperative WSSR (pre-WSSR) and ΔPR as risk factors for CH following CEA. Combined ΔPR, ΔrSO2, ΔMFV, and pre-WSSR had higher sensitivity and specificity than single-modality monitoring for predicting CH.

Conclusion

CFD-based multimodal monitoring effectively identified cerebral perfusion changes and risk factors for CH in CEA patients, with superior predictive accuracy compared to single-modality methods. Nevertheless, further validation is necessary to establish its clinical utility.

Bioengineering vascularization

This Review explores the rapidly evolving field of bioengineered vasculature, a key area of focus in tissue engineering and regenerative medicine. The broad relevance of this topic is attributed to its impacts on a wide range of biological processes, enabling studies in tissue development, fundamental biology and drug discovery, and the applications in tissue engineering and regenerative medicine. We outline the design criteria for bioengineered vasculature and the methodologies for constructing these systems by self-assembly and in microfluidics, organs-on-a-chip and macroscale tubular systems that often rely on biofabrication approaches such as 3D printing. We discuss existing challenges in developing functional vasculature that closely mirrors its native equivalent, including achieving hierarchical branching with organ and vessel-specific endothelial and supporting cells, providing perusable vasculature within organoids and scaling the systems for implantation and direct vascular anastomosis.

Highly scalable and standardized organ-on-chip platform with TEER for biological barrier modeling

The development of new therapies is hampered by the lack of predictive, and patient-relevant in vitro models. Organ-on-chip (OOC) technologies can potentially recreate physiological features and hold great promise for tissue and disease modeling. However, the non-standardized design of these chips and perfusion control systems has been a barrier to quantitative high-throughput screening (HTS). Here we present a scalable OOC microfluidic platform for applied kinetic in vitro assays (AKITA) that is applicable for high, medium, and low throughput. Its standard 96-well plate and 384-well plate layouts ensure compatibility with existing laboratory workflows and high-throughput data collection and analysis tools. The AKITA plate is optimized for the modeling of vascularized biological barriers, primarily the blood-brain barrier, skin, and lung, with precise flow control on a custom rocker. The integration of trans-epithelial electrical resistance (TEER) sensors allows rapid and repeated monitoring of barrier integrity over long time periods. Together with automated liquid handling and compound permeability testing analyses, we demonstrate the flexibility of the AKITA platform for establishing human-relevant models for preclinical drug and precision medicine's efficacy, toxicity, and permeability under near-physiological conditions.

FGL2/FcγRIIB Signalling Mediates Arterial Shear Stress-Mediated Endothelial Cell Apoptosis: Implications for Coronary Artery Bypass Vein Graft Pathogenesis

The sudden exposure of venous endothelial cells (vECs) to arterial fluid shear stress (FSS) is thought to be a major contributor to coronary artery bypass vein graft failure (VGF). However, the effects of arterial FSS on the vEC secretome are poorly characterised. We propose that analysis of the vEC secretome may reveal potential therapeutic approaches to suppress VGF. Human umbilical vein endothelial cells (HUVECs) pre-conditioned to venous FSS (18 h; 1.5 dynes/cm2) were exposed to venous or arterial FSS (15 dynes/cm2) for 24 h. Tandem Mass Tagging proteomic analysis of the vEC secretome identified significantly increased fibroleukin (FGL2) in conditioned media from HUVECs exposed to arterial FSS. This increase was validated by Western blotting. Application of the NFκB inhibitor BAY 11-7085 (1 µM) following pre-conditioning reduced FGL2 release from vECs exposed to arterial FSS. Exposure of vECs to arterial FSS increased apoptosis, measured by active cleaved caspase-3 (CC3) immunocytochemistry, which was likewise elevated in HUVECs treated with recombinant FGL2 (20 ng/mL) for 24 h under static conditions. To determine the mechanism of FGL2-induced apoptosis, HUVECs were pre-treated with a blocking antibody to FcγRIIB, a receptor FGL2 is proposed to interact with, which reduced CC3 levels. In conclusion, our findings indicate that the exposure of vECs to arterial FSS results in increased release of FGL2 via NFκB signalling, which promotes endothelial apoptosis via FcγRIIB signalling. Therefore, the inhibition of FGL2/FcγRIIB signalling may provide a novel approach to reduce arterial FSS-induced vEC apoptosis in vein grafts and suppress VGF.

Modelling and breaking down the biophysical barriers to drug delivery in pancreatic cancer

The pancreatic ductal adenocarcinoma (PDAC) stroma and its inherent biophysical barriers to drug delivery are central to therapeutic resistance. This makes PDAC the most prevalent pancreatic cancer with poor prognosis. The chemotherapeutic drug gemcitabine is used against various solid tumours, including pancreatic cancer, but with only a modest effect on patient survival. The growing PDAC tumour mass with high densities of cells and extracellular matrix (ECM) proteins, i.e., collagen, results in high interstitial pressure, leading to vasculature collapse and a dense, hypoxic, mechanically stiff stroma with reduced interstitial flow, critical to drug delivery to cells. Despite this, most drug studies are performed on cellular models that neglect these biophysical barriers to drug delivery. Microfluidic technology offers a promising platform to emulate tumour biophysical characteristics with appropriate flow conditions and transport dynamics. We present a microfluidic PDAC culture model, encompassing the disease's biophysical barriers to therapeutics, to evaluate the use of the angiotensin II receptor blocker losartan, which has been found to have matrix-depleting properties, on improving gemcitabine efficacy. PDAC cells were seeded into our 5-channel microfluidic device for a 21-day culture to mimic the rigid, collagenous PDAC stroma with reduced interstitial flow, which is critical to drug delivery to the cancer cells, and for assessment with gemcitabine and losartan treatment. With losartan, our culture matrix was more porous with less collagen, resulting in increased hydraulic conductivity of the culture interstitial space and improved gemcitabine effect. We demonstrate the importance of modelling tumour biophysical barriers to successfully assess new drugs and delivery methods.

Stent underexpansion is associated with high wall shear stress: a biomechanical analysis of the shear stent study

Coronary stent underexpansion is associated with restenosis and stent thrombosis. In clinical studies of atherosclerosis, high wall shear stress (WSS) has been associated with activation of prothrombotic pathways, upregulation of matrix metalloproteinases, and future myocardial infarction. We hypothesized that stent underexpansion is predictive of high WSS. WSS distribution was investigated in patients enrolled in the prospective randomized controlled study of angulated coronary arteries randomized to undergo percutaneous coronary intervention with R-ZES or X-EES. WSS was calculated from 3D reconstructions of arteries from intravascular ultrasound (IVUS) and angiography using computational fluid dynamics. A logistic regression model investigated the relationship between WSS and underexpansion and the relationship between underexpansion and stent platform. Mean age was 63±11, 78% were male, 35% had diabetes, mean pre-stent angulation was 36.7°±14.7°. Underexpansion was assessed in 83 patients (6,181 IVUS frames). Frames with stent underexpansion were significantly more likely to exhibit high WSS (> 2.5 Pa) compared to those without underexpansion with an OR of 2.197 (95% CI = [1.233-3.913], p = 0.008). There was no significant association between underexpansion and low WSS (< 1.0 Pa) and no significant differences in underexpansion between R-ZES and X-EES. In the Shear Stent randomized controlled study, underexpanded IVUS frames were more than twice as likely to be associated with high WSS than frames without underexpansion.

Effects of Elasticity on Cell Proliferation in a Tissue-Engineering Scaffold Pore

Scaffolds engineered for in vitro tissue engineering consist of multiple pores where cells can migrate along with nutrient-rich culture medium. The presence of the nutrient medium throughout the scaffold pores promotes cell proliferation, and this process depends on several factors such as scaffold geometry, nutrient medium flow rate, shear stress, cell-scaffold focal adhesions and elastic properties of the scaffold material. While numerous studies have addressed the first four factors, the mathematical approach described herein focuses on cell proliferation rate in elastic scaffolds, under constant flux of nutrients. As cells proliferate, the scaffold pores radius shrinks and thus, in order to sustain the nutrient flux, the inlet applied pressure on the upstream side of the scaffold pore must be increased. This results in expansion of the elastic scaffold pore, which in turn further increases the rate of cell proliferation. Considering the elasticity of the scaffold, the pore deformation allows further cellular growth beyond that of inelastic conditions. In this paper, our objectives are as follows: (i) Develop a mathematical model for describing fluid dynamics, scaffold elasticity and cell proliferation for scaffolds consist of identical nearly cylindrical pores; (ii) Solve the models and then simulate cellular proliferation within an elastic pore. The simulation can emulate real life tissue growth in a scaffold and offer a solution which reduces the numerical burdens. Lastly, our results demonstrated are in qualitative agreement with experimental observations reported in the literature.

Cholesterol efflux regulator ABCA1 exerts protective role against high shear stress-induced injury of HBMECs via regulating PI3K/Akt/eNOS signaling

Background

In brain, microvascular endothelial cells are exposed to various forces, including shear stress (SS). However, little is known about the effects of high shear stress (HSS) on human brain microvascular endothelial cells (HBMECs) and the underlying mechanism. The cholesterol efflux regulator ATP-binding cassette subfamily A member 1 (ABCA1) has been demonstrated to exert protective effect on HBMECs. However, whether ABCA1 is involved in the mechanism underneath the effect of HSS on HBMECs remains obscure. In the present study, a series of experiments were performed to better understand the effect of HSS on cellular processes of HBMECs and the possible involvement of ABCA1 and PI3K/Akt/eNOS in the underlying mechanisms.

Results

HBMECs were subjected to physiological SS (PSS) or high SS (HSS). Cell migration was evaluated using Transwell assay. Apoptotic HBMECs were detected by flow cytometry or caspase3/7 activity. IL-1β, IL-6, MCP-1 and TNF-α levels were measured by ELISA. RT-qPCR and western blotting were used for mRNA and protein expression detection, respectively. ROS and NO levels were detected using specific detection kits. Compared to PSS, HBMECs exhibited decreased cell viability and migration and increased cell apoptosis, increased levels of inflammatory cytokines, and improved ROS and NO productions after HSS treatment. Moreover, HSS downregulated ABCA1 but upregulated the cholesterol efflux-related proteins MMP9, AQP4, and CYP46 and activated PI3K/Akt/eNOS pathway. Overexpression of ABCA1 in HBMECS inhibited PI3K/Akt/eNOS pathway and counteracted the deleterious effects of HSS. Contrary effects were observed by ABCA1 silencing. Inhibiting PI3K/Akt/eNOS pathway mimicked ABCA1 effects, suggesting that ABCA1 protects HBMECs from HSS via PI3K/Akt/eNOS signaling.

Conclusion

These results advanced our understanding on the mechanisms of HSS on HBMECs and potentiated ABCA1/PI3K/Akt/eNOS pathway as therapeutic target for cerebrovascular diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12868-022-00748-2.

Progress in research on the role of exosomal miRNAs in the diagnosis and treatment of cardiovascular diseases

Cardiovascular diseases are the most common diseases threatening the health of the elderly, and the incidence and mortality rates associated with cardiovascular diseases remain high and are increasing gradually. Studies on the treatment and prevention of cardiovascular diseases are underway. Currently, several research groups are studying the role of exosomes and biomolecules incorporated by exosomes in the prevention, diagnosis, and treatment of clinical diseases, including cardiovascular diseases. Now, based on the results of published studies, this review discusses the characteristics, separation, extraction, and identification of exosomes, specifically the role of exosomal miRNAs in atherosclerosis, myocardial injury and infarction, heart failure, aortic dissection, myocardial fibrosis, ischemic reperfusion, atrial fibrillation, and other diseases. We believe that the observations noted in this article will aid in the prevention, diagnosis, and treatment of cardiovascular diseases.

Mulberry Leaf and Neochlorogenic Acid Alleviates Glucolipotoxicity-Induced Oxidative Stress and Inhibits Proliferation/Migration via Downregulating Ras and FAK Signaling Pathway in Vascular Smooth Muscle Cell

Mulberry leaf (Morus alba L.) has been used as a health food and in traditional medicine to treat several metabolic diseases, including diabetes, hypertension, and hyperlipidemia. However, the mechanism by which mulberry leaf and its functional components mediate atherosclerosis remains unclear. This study aimed to determine the effect of mulberry leaf extract (MLE) and its major component, neochlorogenic acid (nCGA), on the proliferation and migration of rat aortic vascular smooth muscle cells (VSMCs, A7r5 cell line) under diabetic cultured conditions (oleic acid and high glucose, OH). Our findings showed that MLE and nCGA significantly inhibited cell proliferation and migration in A7r5 cells as determined by a scratch wound assay and a Transwell assay. Furthermore, we observed MLE and nCGA inhibited cell proliferation and migration, such as reducing the phosphoinositide 3-kinases (PI3K)/protein kinase B (Akt), focal adhesion kinase (FAK), and small GTPase proteins using Western blot analysis. In conclusion, we confirmed the anti-atherosclerotic effects of MLE and nCGA in reducing vascular smooth muscle cell (VSMC) migration and proliferation under diabetic cultured conditions via inhibition of FAK/small GTPase proteins, PI3K/Akt, and Ras-related signaling.

A Review of Functional Analysis of Endothelial Cells in Flow Chambers

The vascular endothelial cells constitute the innermost layer. The cells are exposed to mechanical stress by the flow, causing them to express their functions. To elucidate the functions, methods involving seeding endothelial cells as a layer in a chamber were studied. The chambers are known as parallel plate, T-chamber, step, cone plate, and stretch. The stimulated functions or signals from endothelial cells by flows are extensively connected to other outer layers of arteries or organs. The coculture layer was developed in a chamber to investigate the interaction between smooth muscle cells in the middle layer of the blood vessel wall in vascular physiology and pathology. Additionally, the microfabrication technology used to create a chamber for a microfluidic device involves both mechanical and chemical stimulation of cells to show their dynamics in in vivo microenvironments. The purpose of this study is to summarize the blood flow (flow inducing) for the functions connecting to endothelial cells and blood vessels, and to find directions for future chamber and device developments for further understanding and application of vascular functions. The relationship between chamber design flow, cell layers, and microfluidics was studied.

Acute shear stress and vein graft disease

The long saphenous vein is commonly used in cardiac surgery to bypass occluded coronary arteries. Its use is complicated by late stenosis and occlusion due to the development of intimal hyperplasia. It is accepted that intimal hyperplasia is a multifactorial inflammatory process that starts immediately after surgery. The role of acute changes in haemodynamic conditions when the vein is implanted into arterial circulation, especially shear stress, is not fully appreciated. This review provides an overview of intimal hyperplasia and the effect of acute shear stress changes on the activation of pro-inflammatory mediators.

Mechanism of cell death of endothelial cells regulated by mechanical forces

Cell death of endothelial cells (ECs) is a common devastating consequence of various vascular-related diseases. Atherosclerosis, hypertension, sepsis, diabetes, cerebral ischemia and cardiac ischemia/reperfusion injury, and chronic kidney disease remain major causes of morbidity and mortality worldwide, in which ECs are constantly subjected to a great amount of dynamic changed mechanical forces including shear stress, extracellular matrix stiffness, mechanical stretch and microgravity. A thorough understanding of the regulatory mechanisms by which the mechanical forces controlled the cell deaths including apoptosis, autophagy, and pyroptosis is crucial for the development of new therapeutic strategies. In the present review, experimental and clinical data highlight that nutrient depletion, oxidative stress, tumor necrosis factor-α, high glucose, lipopolysaccharide, and homocysteine possess cytotoxic effects in many tissues and induce apoptosis of ECs, and that sphingosine-1-phosphate protects ECs. Nevertheless, EC apoptosis in the context of those artificial microenvironments could be enhanced, reduced or even reversed along with the alteration of patterns of shear stress. An appropriate level of autophagy diminishes EC apoptosis to some extent, in addition to supporting cell survival upon microenvironment challenges. The intervention of pyroptosis showed a profound effect on atherosclerosis. Further cell and animal studies are required to ascertain whether the alterations in the levels of cell deaths and their associated regulatory mechanisms happen at local lesion sites with considerable mechanical force changes, for preventing senescence and cell deaths in the vascular-related diseases.

Role of Venous Endothelial Cells in Developmental and Pathologic Angiogenesis

BACKGROUND

Angiogenesis is a dynamic process that involves expansion of a preexisting vascular network that can occur in a number of physiological and pathological settings. Despite its importance, the origin of the new angiogenic vasculature is poorly defined. In particular, the primary subtype of endothelial cells (capillary, venous, arterial) driving this process remains undefined.

METHODS

Endothelial cells were fate-mapped with the use of genetic markers specific to arterial and capillary cells. In addition, we identified a novel venous endothelial marker gene (Gm5127) and used it to generate inducible venous endothelium-specific Cre and Dre driver mouse lines. Contributions of these various types of endothelial cells to angiogenesis were examined during normal postnatal development and in disease-specific setting.

RESULTS

Using a comprehensive set of endothelial subtype-specific inducible reporter mice, including tip, arterial, and venous endothelial reporter lines, we showed that venous endothelial cells are the primary endothelial subtype responsible for the expansion of an angiogenic vascular network. During physiological angiogenesis, venous endothelial cells proliferate, migrating against the blood flow and differentiating into tip, capillary, and arterial endothelial cells of the new vasculature. Using intravital 2-photon imaging, we observed venous endothelial cells migrating against the blood flow to form new blood vessels. Venous endothelial cell migration also plays a key role in pathological angiogenesis. This was observed both in formation of arteriovenous malformations in mice with inducible endothelium-specific Smad4 deletion mice and in pathological vessel growth seen in oxygen-induced retinopathy.

CONCLUSIONS

Our studies establish that venous endothelial cells are the primary endothelial subtype responsible for normal expansion of vascular networks, formation of arteriovenous malformations, and pathological angiogenesis. These observations highlight the central role of the venous endothelium in normal development and disease pathogenesis.

Vascular dysfunction and pathology: focus on mechanical forces

The role of mechanical forces is emerging as a new player in the pathophysiologic programming of the cardiovascular system. The ability of the cells to 'sense' mechanical forces does not relate only to perception of movement or flow, as intended traditionally, but also to the biophysical properties of the extracellular matrix, the geometry of the tissues, and the force distribution inside them. This is also supported by the finding that cells can actively translate mechanical cues into discrete gene expression and epigenetic programming. In the present review, we will contextualize these new concepts in the vascular pathologic programming.

Targeting of the COX-2/PGE2 axis enhances the antitumor activity of T7 peptide in vitro and in vivo

T7 peptide is considered as an antiangiogenic polypeptide. The presents study aimed to further detect the antiangiogenic mechanisms of T7 peptide and determine whether combining T7 peptide and meloxicam (COX-2/PGE2 specific inhibitor) could offer a better therapy to combat hepatocellular carcinoma (HCC). T7 peptide suppressed the proliferation, migration, tube formation, and promoted the apoptosis of endothelial cells under both normoxic and hypoxic conditions via integrin α3β1 and αvβ3 pathways. Cell proliferation, migration, apoptosis, or tube formation ability were detected, and the expression of integrin-associated regulatory proteins was detected. The anti-tumor activity of T7 peptide, meloxicam, and their combination were evaluated in HCC tumor models established in mice. T7 peptide suppressed the proliferation, migration, tube formation, and promoted the apoptosis of endothelial cells under both normoxic and hypoxic conditions via integrin α3β1 and αvβ3 pathways. Meloxicam enhanced the activity of T7 peptide under hypoxic condition. T7 peptide partly inhibited COX-2 expression via integrin α3β1 not αvβ3-dependent pathways under hypoxic condition. T7 peptide regulated apoptosis associated protein through MAPK-dependent and -independent pathways under hypoxic condition. The MAPK pathway was activated by the COX-2/PGE2 axis under hypoxic condition. The combination of T7 and meloxicam showed a stronger anti-tumor effect against HCC tumors in mice. The data highlight that meloxicam enhanced the antiangiogenic activity of T7 peptide in vitro and in vivo.

The role of endothelial shear stress on haemodynamics, inflammation, coagulation and glycocalyx during sepsis

Sepsis is a multifactorial syndrome primarily determined by the host response to an invading pathogen. It is common, with over 48 million cases worldwide in 2017, and often lethal. The sequence of events in sepsis begins with the damage of endothelium within the microvasculature, as a consequence of the inflammatory and coagulopathic responses to the pathogen that can progress to multiple organ failure and death. Most therapeutic interventions target the inflammation and coagulation pathways that act as an auto-amplified vicious cycle, which, if unchecked can be fatal. Normal blood flow and shear stress acting on a healthy endothelium and intact glycocalyx have anti-inflammatory, anticoagulant and self-repairing effects. During early stages of sepsis, the vascular endothelium and its glycocalyx become dysfunctional, yet they are essential components of resuscitation and recovery from sepsis. The effects of shear forces on sepsis-induced endothelial dysfunction, including inflammation, coagulation, complement activation and microcirculatory breakdown are reviewed. It is suggested that early therapeutic strategies should prioritize on the restoration of shear forces and endothelial function and on the preservation of the endothelial-glycocalyx barrier.

Berberine inhibits proliferation and apoptosis of vascular smooth muscle cells induced by mechanical stretch via the PDI/ERS and MAPK pathways

AIMS

We recently demonstrated that mechanical stretch increases the proliferation and apoptosis of vascular smooth muscle cells (VSMCs) by activating the protein disulfide isomerase (PDI) redox system, thus accelerating atherosclerotic lesion formation in the transplanted vein. At present, there are no efficient intervention measures to prevent this phenomenon. Berberine inhibits pathological vascular remodeling caused by hypertension, but the underlying mechanism is controversial. Herein, we investigate the role of berberine and the underlying mechanism of its effects on mechanical stretch-induced VSMC proliferation and apoptosis.

MAIN METHODS

Mouse VSMCs cultivated on flexible membranes were pretreated for 1 h with one of the following substances: berberine, PDI inhibitor bacitracin, MAPK inhibitors, or ERS inhibitor 4-PBA. VSMCs were then subjected to mechanical stretch. Immunofluorescence and western blot were used to detect proliferation and apoptosis, as well as to analyze signaling pathways in VSMCs.

KEY FINDINGS

Our results showed that berberine inhibits the PDI-endoplasmic reticulum stress system, thereby attenuating the simultaneous increase of VSMC proliferation and apoptosis in response to mechanical stretch. Interestingly, MAPK inhibitors PD98059, SP600125, and SB202190 significantly reduced the activation of ERS signaling cascades, and their combination with berberine had additive effects. The ERS inhibitor 4-PBA reduced PDI activation and ERS signaling, but not MAPK phosphorylation. Moreover, caspase-3 and caspase-12 were downregulated by berberine.

SIGNIFICANCE

These results illustrate a novel mechanism of action of berberine that has practical implications. Our data provide important insights for the prevention and treatment of vascular remodeling and diseases caused by mechanical stretching during hypertension.

Fluid shear stress modulates endothelial inflammation by targeting LIMS2

Mechanosensitive genes regulate multiple cardiovascular pathophysiological processes and disorders; however, the role of flow-sensitive genes in atherosclerosis is still unknown. In this study, we identify LIM Zinc Finger Domain Containing 2 (LIMS2) that acts as a mechanosensitive gene downregulated by disturbed flow (d-flow) both in human endothelial cells (ECs) in vitro and in mice in vivo. Mechanistically, d-flow suppresses LIMS2 expression, which leads to endothelial inflammation by upregulating typical inflammatory factors, VCAM-1, and ICAM-1 in human ECs. The findings indicate that LIMS2, the new flow-sensitive gene, may help us to find a new insight to explain how d-flow caused endothelial inflammation and provide a new therapeutic approach for atherosclerosis in the future.