Aspirin-Triggered Resolvin D1 Inhibits TGF-β1-Induced EndMT through Increasing the Expression of Smad7 and Is Closely Related to Oxidative Stress

Beyond VICs: Shedding light on the overlooked VECs in calcific aortic valve disease

Calcific aortic valve disease (CAVD) is prevalent in developed nations and has emerged as a pressing global public health concern due to population aging. The precise etiology of this disease remains uncertain, and recent research has primarily focused on examining the role of valvular interstitial cells (VICs) in the development of CAVD. The predominant treatment options currently available involve open surgery and minimally invasive interventional surgery, with no efficacious pharmacological treatment. This article seeks to provide a comprehensive understanding of valvular endothelial cells (VECs) from the aspects of valvular endothelium-derived nitric oxide (NO), valvular endothelial mechanotransduction, valvular endothelial injury, valvular endothelial-mesenchymal transition (EndMT), and valvular neovascularization, which have received less attention, and aims to establish their role and interaction with VICs in CAVD. The ultimate goal is to provide new perspectives for the investigation of non-invasive treatment options for this disease.

β-Sitosterol Inhibits The Proliferation of Endometrial Cells via Regulating Smad7-Mediated TGF-β/Smads Signaling Pathway

OBJECTIVE

To investigate the effect of β-sitosterol on endometrial cells to understand the underlying mechanism.

MATERIALS AND METHODS

This is a laboratory-based experimental study conducted on animals and cells. Histological assays were performed to determine the effect of β-sitosterol on endometrial cells. The CCK-8 assay was used to assess the inhibitory effect of β-sitosterol on the proliferation of ectopic endometrial stromal cells (hEM15A). Flow cytometry was performed to evaluate the induction of apoptosis by β-sitosterol in hEM15A cells. The transwell invasion assay was conducted to measure the suppression of hEM15A cell migration by β-sitosterol. Western blot analyses were performed to analyze the effect of β-sitosterol on the expression of Smad family member 7 (Smad7) and the activity of transforming growth factor-β (TGF-β1), as well as the phosphorylation of Smad2 and Smad3.

RESULTS

Histological assays showed that β-sitosterol regulates histopathology and induces apoptosis of endometrial cells in vivo. The CCK-8 assay revealed that β-sitosterol could inhibit the proliferation of hEM15A in human endometriosis patients. Flow cytometry showed that apoptosis was triggered by β-sitosterol in hEM15A. The transwell invasion assay indicated that the hEM15A migration under the β-sitosterol treatment group was suppressed. Western blot analyses suggested that β-sitosterol increased the expression of Smad7, decreased the activity of TGF-β1, and reduced the phosphorylation of Smad2 and Smad3. The effect of β-sitosterol was weakened by the silence of Smad7.

CONCLUSION

The results suggest that β-sitosterol can inhibit the proliferation of endometrial cells and relieve endometriosis by inhibiting TGF-β-induced phosphorylation of Smads through regulation of Smad7.

Endothelial Cell Phenotype, a Major Determinant of Venous Thrombo-Inflammation

Reduced blood flow velocity in the vein triggers inflammation and is associated with the release into the extracellular space of alarmins or damage-associated molecular patterns (DAMPs). These molecules include extracellular nucleic acids, extracellular purinergic nucleotides (ATP, ADP), cytokines and extracellular HMGB1. They are recognized as a danger signal by immune cells, platelets and endothelial cells. Hence, endothelial cells are capable of sensing environmental cues through a wide variety of receptors expressed at the plasma membrane. The endothelium is then responding by expressing pro-coagulant proteins, including tissue factor, and inflammatory molecules such as cytokines and chemokines involved in the recruitment and activation of platelets and leukocytes. This ultimately leads to thrombosis, which is an active pro-inflammatory process, tightly regulated, that needs to be properly resolved to avoid further vascular damages. These mechanisms are often dysregulated, which promote fibrinolysis defects, activation of the immune system and irreversible vascular damages further contributing to thrombotic and inflammatory processes. The concept of thrombo-inflammation is now widely used to describe the complex interactions between the coagulation and inflammation in various cardiovascular diseases. In endothelial cells, activating signals converge to multiple intracellular pathways leading to phenotypical changes turning them into inflammatory-like cells. Accumulating evidence suggest that endothelial to mesenchymal transition (EndMT) may be a major mechanism of endothelial dysfunction induced during inflammation and thrombosis. EndMT is a biological process where endothelial cells lose their endothelial characteristics and acquire mesenchymal markers and functions. Endothelial dysfunction might play a central role in orchestrating and amplifying thrombo-inflammation thought induction of EndMT processes. Mechanisms regulating endothelial dysfunction have been only partially uncovered in the context of thrombotic diseases. In the present review, we focus on the importance of the endothelial phenotype and discuss how endothelial plasticity may regulate the interplay between thrombosis and inflammation. We discuss how the endothelial cells are sensing and responding to environmental cues and contribute to thrombo-inflammation with a particular focus on venous thromboembolism (VTE). A better understanding of the precise mechanisms involved and the specific role of endothelial cells is needed to characterize VTE incidence and address the risk of recurrent VTE and its sequelae.

Chlorogenic acid improves diabetic retinopathy by alleviating blood-retinal-barrier dysfunction via inducing Nrf2 activation

As one of the major diabetic microvascular complications, diabetic retinopathy (DR) is mainly initiated by the blood-retinal barrier (BRB) dysfunction. Chlorogenic acid (CGA) is a natural polyphenolic compound in Lonicerae Japonicae Flos, which traditionally has the beneficial function for eyes and is commonly included in many anti-diabetic formulas. In this study, the potential protective mechanism of CGA against DR was investigated. Streptozotocin (STZ) was used to induce diabetes in mice. CGA attenuated BRB dysfunction and reversed endothelial-mesenchymal transition (EndoMT) and epithelial-mesenchymal transition (EMT) in retinas in vivo. CGA inhibited microglia activation and reduced tumor necrosis factor (TNF)α release both in vivo and in vitro. CGA promoted nuclear factor erythroid 2-related factor 2 (Nrf2) activation and prevented EndoMT/EMT in TNFα-treated human retinal endothelial cells (HRECs) or retinal pigment epithelial APRE19 cells. CGA alleviated endothelial/epithelial barrier oxidative injury in HRECs or APRE19 cells stimulated with TNFα, but this effect was disappeared in cells co-incubated with Nrf2 inhibitor. Additionally, the CGA-supplied alleviation on BRB damage and EndoMT/EMT was markedly weakened in retinas from STZ-treated Nrf2 knock-out mice. All results suggest that CGA improves DR through attenuating BRB injury by reducing microglia-initiated inflammation and preventing TNFα-induced EndoMT/EMT and oxidative injury via inducing Nrf2 activation.

ATRvD1 Attenuates Renal Tubulointerstitial Injury Induced by Albumin Overload in Sepsis-Surviving Mice

Novel strategies for the prevention and treatment of sepsis-associated acute kidney injury and its long-term outcomes have been required and remain a challenge in critical care medicine. Therapeutic strategies using lipid mediators, such as aspirin-triggered resolvin D1 (ATRvD1), can contribute to the resolution of acute and chronic inflammation. In this study, we examined the potential effect of ATRvD1 on long-term kidney dysfunction after severe sepsis. Fifteen days after cecal ligation and puncture (CLP), sepsis-surviving BALB/c mice were subjected to a tubulointerstitial injury through intraperitoneal injections of bovine serum albumin (BSA) for 7 days, called the subclinical acute kidney injury (subAKI) animal model. ATRvD1 treatment was performed right before BSA injections. On day 22 after CLP, the urinary protein/creatinine ratio (UPC), histologic parameters, fibrosis, cellular infiltration, apoptosis, inflammatory markers levels, and mRNA expression were determined. ATRvD1 treatment mitigated tubulointerstitial injury by reducing proteinuria excretion, the UPC ratio, the glomerular cell number, and extracellular matrix deposition. Pro-fibrotic markers, such as transforming growth factor β (TGFβ), type 3 collagen, and metalloproteinase (MMP)-3 and -9 were reduced after ATRvD1 administration. Post-septic mice treated with ATRvD1 were protected from the recruitment of IBA1⁺ cells. The interleukin-1β (IL-1β) levels were increased in the subAKI animal model, being attenuated by ATRvD1. Tumor necrosis factor-α (TNF-α), IL-10, and IL-4 mRNA expression were increased in the kidney of BSA-challenged post-septic mice, and it was also reduced after ATRvD1. These results suggest that ATRvD1 protects the kidney against a second insult such as BSA-induced tubulointerstitial injury and fibrosis by suppressing inflammatory and pro-fibrotic mediators in renal dysfunction after sepsis.

MiR-200c-3p promotes ox-LDL-induced endothelial to mesenchymal transition in human umbilical vein endothelial cells through SMAD7/YAP pathway

BACKGROUND

Endothelial to mesenchymal transition (EndMT) participates in the progression of atherosclerosis (AS). MiR-200c-3p has been implicated in EndMT. However, the functional role of miR-200c-3p in AS remains largely unknown. Here, we demonstrated the critical role of miR-200c-3p in regulating EndMT in AS.

METHODS

ApoE-/- mice were fed with high-fat diet to establish AS mouse model, and human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL) to mimic AS cell model. The expression of miR-200c-3p, SMAD7 and YAP in ApoE-/- mice and HUVECs was detected by quantitative real-time PCR. Rhodamine phalloidin staining and Western blot were performed to observe cell morphology and EndMT marker expression of HUVECs. Luciferase reporter assay and Co-Immunoprecipitation were performed to verify the relationship among miR-200c-3p, SMAD7, and YAP.

RESULTS

MiR-200c-3p was highly expressed, and SMAD7 and YAP were down-regulated in the aortic tissues of ApoE-/- mice and ox-LDL-treated HUVECs. MiR-200c-3p overexpression promoted the transformation of ox-LDL-treated HUVECs from cobblestone-like epithelial phenotype to a spindle-like mesenchymal phenotype. Meanwhile, miR-200c-3p up-regulation repressed the expression of endothelial markers CD31 and vWF and promoted the expression of mesenchymal markers α-SMA and vimentin in the ox-LDL-treated HUVECs. MiR-200c-3p inhibited SMAD7 and YAP expression by interacting with 3' untranslated region of SMAD7. Moreover, miR-200c-3p promoted EndMT in ox-LDL-treated HUVECs by inhibiting SMAD7/YAP pathway.

CONCLUSION

This work demonstrated that MiR-200c-3p promoted ox-LDL-induced EndMT in HUVECs through SMAD7/YAP pathway, which may be important for the onset of atherosclerosis.

Naringin Ameliorates Monocrotaline-Induced Pulmonary Arterial Hypertension Through Endothelial-To-Mesenchymal Transition Inhibition

Pulmonary arterial hypertension (PAH) caused by enhanced arterial pressure increases vessel resistance in the lung. Endothelial-to-mesenchymal transition (EndMT) plays key roles in the vascular remodeling in PAH. Naringin, a protective gaseous mediator is commonly extracted from tomatoes and citrus fruits (such as grapefruits), and demonstrates anti-inflammation, anti-oxidant, anti-proliferation, and anti-tumor effects. Meanwhile, the association of Naringin and the process of EndMT is still unclear. In this study, monocrotaline (MCT) administration (60 mg/kg) was delivered for the induction of PAH in rats. Following this, Naringin (concentrations: 25, 50, and 100 mg/kg/day) was used for treatments. Human Umbilical Vein Endothelial Cells (HUVECs) were stimulated with Naringin and transforming growth factor β1 (TGFβ1, 10 ng/ml). As the result, Naringin was demonstrated to inhibit EndMT and alleviate PAH progression. In particular, in HUVECs, Naringin significantly suppressed the mesenchymal marker expression induced by TGFβ1 treatment, enhanced the endothelial marker expression, and inhibited the activation of ERK and NF-κB signaling pathways. To conclude, this study provided novel evidence suggesting the beneficial effects of Naringin in PAH through the inhibition of the ERK and NF-κB signaling pathways and the EndMT progression in pulmonary arteries.

Modulation of EndMT by Hydrogen Sulfide in the Prevention of Cardiovascular Fibrosis

Endothelial mesenchymal transition (EndMT) has been described as a fundamental process during embryogenesis; however, it can occur also in adult age, underlying pathological events, including fibrosis. Indeed, during EndMT, the endothelial cells lose their specific markers, such as vascular endothelial cadherin (VE-cadherin), and acquire a mesenchymal phenotype, expressing specific products, such as α-smooth muscle actin (α-SMA) and type I collagen; moreover, the integrity of the endothelium is disrupted, and cells show a migratory, invasive and proliferative phenotype. Several stimuli can trigger this transition, but transforming growth factor (TGF-β1) is considered the most relevant. EndMT can proceed in a canonical smad-dependent or non-canonical smad-independent manner and ultimately regulate gene expression of pro-fibrotic machinery. These events lead to endothelial dysfunction and atherosclerosis at the vascular level as well as myocardial hypertrophy and fibrosis. Indeed, EndMT is the mechanism which promotes the progression of cardiovascular disorders following hypertension, diabetes, heart failure and also ageing. In this scenario, hydrogen sulfide (H₂S) has been widely described for its preventive properties, but its role in EndMT is poorly investigated. This review is focused on the evaluation of the putative role of H₂S in the EndMT process.

Impact of resolvin mediators in the immunopathology of diabetes and wound healing

Introduction: Wound healing in diabetes may be delayed by persistent wound infection due to deficient immune and cellular response to tissue injury. Hyperglycemia due to decreased insulin availability and increased insulin resistance affects the immune response of the body. Accumulation of inflammatory immune cells and pro-inflammatory cytokines results in chronic inflammation and an altered resolution and remodeling phase of wound healing.Areas covered: Pro-resolving mediators called 'resolvins' target the resolution phase of wound healing and are becoming an area of increased interest. Resolvins stimulate self-limited innate immune responses and enhance innate microbial killing and clearance. Resolvins resolve inflammation by decreasing neutrophil infiltration and transmigration, increasing the phagocytic activity of macrophages, decreasing adipose tissue macrophages, downregulating platelet activation, suppressing nuclear factor-kappa beta activation, promoting the apoptosis of polymorphonuclear leukocytes, and improving insulin sensitivity. This review discusses the role of resolvins in diabetic wound healing and potential therapeutic strategies. The review is based on a literature search of PubMed and the Web of Science restricted to publications between January 2001 and October 2020.Expert opinion: There is increasing support for the use of resolvins in clinical applications related to diabetes and wound healing. Further research will help clarify this potential.

Endothelial to Mesenchymal Transition in the Cardiogenesis and Cardiovascular Diseases

Today, cardiovascular diseases remain a leading cause of morbidity and mortality worldwide. Endothelial to mesenchymal transition (EndMT) does not only play a major role in the course of development but also contributes to several cardiovascular diseases in adulthood. EndMT is characterized by down-regulation of the endothelial proteins and highly up-regulated fibrotic specific genes and extracellular matrix-forming proteins. EndMT is also a transforming growth factor-β-driven (TGF-β) process in which endothelial cells lose their endothelial characteristics and acquire a mesenchymal phenotype with expression of α-smooth muscle actin (α-SMA), fibroblast-specific protein 1, etc. EndMT is a vital process during cardiac development, thus disrupted EndMT gives rise to the congenital heart diseases, namely septal defects and valve abnormalities. In this review, we have discussed the main signaling pathways and mechanisms participating in the process of EndMT such as TGF-β and Bone morphogenetic protein (BMP), Wnt^#, and Notch signaling pathway and also studied the role of EndMT in physiological cardiovascular development and pathological conditions including myocardial infarction, pulmonary arterial hypertension, congenital heart defects, cardiac fibrosis, and atherosclerosis. As a perspective view, having a clear understanding of involving cellular and molecular mechanisms in EndMT and conducting Randomized controlled trials (RCTs) with a large number of samples for involving pharmacological agents may guide us into novel therapeutic approaches of congenital disorders and heart diseases.

Therapeutic Effects of Specialized Pro-Resolving Lipids Mediators on Cardiac Fibrosis via NRF2 Activation

Heart disease is the number one mortality disease in the world. In particular, cardiac fibrosis is considered as a major factor causing myocardial infarction and heart failure. In particular, oxidative stress is a major cause of heart fibrosis. In order to control such oxidative stress, the importance of nuclear factor erythropoietin 2 related factor 2 (NRF2) has recently been highlighted. In this review, we will discuss the activation of NRF2 by docosahexanoic acid (DHA), eicosapentaenoic acid (EPA), and the specialized pro-resolving lipid mediators (SPMs) derived from polyunsaturated lipids, including DHA and EPA. Additionally, we will discuss their effects on cardiac fibrosis via NRF2 activation.

Protective Effects and Molecular Signaling of n-3 Fatty Acids on Oxidative Stress and Inflammation in Retinal Diseases

Oxidative stress and inflammation play crucial roles in the development and progression of retinal diseases. Retinal damage by various etiologies can result in retinopathy of prematurity (ROP), diabetic retinopathy (DR), and age-related macular degeneration (AMD). n-3 fatty acids are essential fatty acids and are necessary for homeostasis. They are important retinal membrane components and are involved in energy storage. n-3 fatty acids also have antioxidant and anti-inflammatory properties, and their suppressive effects against ROP, DR, and AMD have been previously evaluated. α-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and their metabolites have been shown to alleviate retinal oxidative stress and inflammation involving various biological signaling pathways. In this review, we summarize the current understanding of the n-3 fatty acids effects on the mechanisms of these retinal diseases and how they exert their therapeutic effects, focusing on ALA, EPA, DHA, and their metabolites. This knowledge may provide new remedial strategies for n-3 fatty acids in the prevention and treatment of retinal diseases associated with oxidative stress and inflammation.

The Effect of Salvianolic Acid on Vascular Protection and Possible Mechanisms

Salvia miltiorrhiza (Danshen), as an important traditional Chinese medicinal plant, has been used in China for the treatment of cardiovascular diseases for hundreds of years. Salvianolic acids (salvianolic acid A and salvianolic acid B) as the most abundant water-soluble component extracted from Salvia miltiorrhiza have attracted more and more attention from cardiovascular scientists due to its comprehensive cardiovascular actions. In vivo and in vitro studies have rendered salvianolic acid an excellent drug candidate for the treatment and prevention of cardiovascular diseases. In this review, we surveyed the protective effects of salvianolic acid A and salvianolic acid B against cardiovascular diseases and the pharmacological basis, providing a strong scientific rationale for elucidating the important role of Salvia miltiorrhiza in cardiovascular therapy. More importantly, we also hope to provide new inspiration and perspectives on the development and innovation of small-molecule cardiovascular drugs based on salvianolic acid.

Curcumin attenuates endothelial cell fibrosis through inhibiting endothelial-interstitial transformation

Curcumin (Cur) has various pharmacological activities, including anti-inflammatory, antiapoptotic and anticancer effects. However, there is no report on the effect of Cur on endothelial cell fibrosis. This study was designed to investigate the effect and mechanism of Cur on endothelial cell fibrosis. An endothelial cell fibrosis model was established by using transforming growth factor (TGF) induction. Proliferation assays, qRT-PCR, western blotting and immunostaining were performed to investigate the effects and mechanism of Cur on endothelial cell fibrosis. We found that in human umbilical vein endothelial cells (HUVECs), TGF-β1 treatment significantly decreased the expression of nuclear factor erythroid-2-related factor 2 (NRF-2), dimethylarginine dimethylaminohydrolase-1 (DDAH1), and VE-cadherin, the secretion of cellular nitric oxide (NO) and the activity of nitrous oxide synthase (NOS), while asymmetric dimethylarginine (ADMA) and the release of inflammatory factors were elevated. Immunofluorescence showed decreased CD31 and increased α-smooth muscle actin (α-SMA). Overexpression of NRF-2 significantly attenuated the effects of TGF-β1, while downregulation of DDAH1 potently counteracted the effect of NRF-2. In addition, ADMA treatment resulted in similar results to those of TGF-β1, and Cur significantly attenuated the effect of TGF-β1, accompanied by increased VE-cadherin, DDAH1 and NRF-2 and decreased matrix metalloproteinase-9 (MMP-9) and extracellular regulated protein kinases 1/2 (ERK1/2) phosphorylation. The NRF-2 inhibitor ML385 had the opposite effect as that of Cur. These results demonstrated that Cur inhibits TGF-β1-induced endothelial-to-mesenchymal transition (EndMT) by stimulating DDAH1 expression via the NRF-2 pathway, thus attenuating endothelial cell fibrosis.

EOFAZ inhibits endothelial‑to‑mesenchymal transition through downregulation of KLF4

Essential oil from Alpinia zerumbet rhizome (EOFAZ), which is termed Yan shanjiang in China, is extensively used as an herbal medicine in the Guizhou area and has been shown to protect against the damaging effects of cardiovascular injury in vitro and in vivo. In the present study, it was hypothesized that the protective effects of EOFAZ on transforming growth factor (TGF)-β1-induced endothelial-to-mesenchymal transition (EndMT) in human umbilical vein endothelial cells (HUVECs) were mediated by inhibition of Krüppel-like factor 4 (KLF4). Cell motility was assessed using wound healing and Transwell assays. The expression of endothelial markers and mesenchymal markers were determined by reverse transcription-quantitative PCR, immunofluorescence staining and western blotting, and additionally, phosphorylated NF-κB p65 expression was determined by western blotting. Furthermore, the involvement of KLF4 in EndMT was determined using RNA interference to knockdown the expression of KLF4. TGF-β1 treatment significantly promoted EndMT, as evidenced by downregu-lation of vascular endothelial-cadherin and upregulation of α-smooth muscle actin in HUVECs, and by enhancing cell migration. Small interfering RNA-mediated knockdown of KLF4 reversed TGF-β1-induced EndMT. Additionally, treatment with EOFAZ inhibited TGF-β1-induced EndMT in a dose-dependent manner. These results suggest that TGF-β1 may induce EndMT through upregulation of KLF4, and this may be reversed by EOFAZ. Therefore, EOFAZ was shown to inhibit TGF-β1-induced EndMT through regulation of KLF4.

TGF-β1-induced SMAD2/3/4 activation promotes RELM-β transcription to modulate the endothelium-mesenchymal transition in human endothelial cells

Endothelial-to-mesenchymal transition (EndMT), which is characterized by increased proliferation, migration and invasion of endothelial cells, increased expression of mesenchymal markers and reduced expression of endothelial markers, has been reported to be closely related to the pathogenesis of several diseases, including pulmonary fibrosis. Resistin-like molecule-β (RELM-β), also known as "found in inflammatory zone 2″ (FIIZ2), plays an essential role in airway remodeling and pulmonary fibrosis; however, its role and mechanism in EndMT remain unclear. Herein, we used TGF-β1-induced EndMT cell model in human umbilical vein endothelial cells (HUVECs) and human primary pulmonary artery endothelial cells (HPAECs) to investigate the function and mechanism of RELM-β in TGF-β1-induced EndMT in endothelial cell lines. We found that TGF-β1 stimulation significantly upregulated RELM-β expression; RELM-β knockdown could attenuate TGF-β1-induced cell proliferation and migration of endothelial cell lines and changes in protein levels of EndMT markers. SB432542, an inhibitor of SMADs, could partially reverse TGF-β1-induced RELM-β expression, endothelial cell migration and changes in EndMT marker protein levels. SMADs complex exerted its effects through SMAD2/3/4 complex mediating RELM-β transcription. In conclusion, TGF-β1 induces RELM-β transcription to promote EndMT in HUVECs and HPAECs through activation of SMAD2/3/4; blocking SMADs-mediated RELM-β transcription might ameliorate TGF-β1-induced EndMT in endothelial cells.

DUOX2-mediated production of reactive oxygen species induces epithelial mesenchymal transition in 5-fluorouracil resistant human colon cancer cells

The therapeutic benefits offered by 5-fluorouracil (5-FU) are limited because of the acquisition of drug resistance, the main cause of treatment failure and metastasis. The ability of the cancer cells to undergo epithelial-mesenchymal transition (EMT) contributes significantly to cancer metastatic potential and chemo-resistance. However, the underlying molecular mechanisms of 5-FU-resistance have remained elusive. Here, we show that reactive oxygen species (ROS), produced by dual oxidase 2 (DUOX2), promote 5-FU-induced EMT. First, we showed that 5-FU–resistant SNUC5 colon cancer cells (SNUC5/FUR cells) undergo EMT by analyzing the expression of EMT markers such as N-cadherin, vimentin and E-cadherin. In addition, we found that the resistant cells expressed higher levels of Snail, Slug, Twist and Zeb1, which are all critical EMT regulators and had enhanced migratory and invasive capabilities. Furthermore, SNUC5/FUR cells had increased level of DUOX2, resulting in increased ROS level. This effect was due to the enhanced binding of the ten eleven translocation 1 (TET1) demethylase to the DUOX2 promoter in the SNUC5/FUR cells. Importantly, silencing of TET1 reversed the effects of 5-FU on the cells. Finally, the antioxidant N-acetylcysteine attenuated the effects of 5-FU on EMT and metastasis. Our study demonstrates the existence of a TET1/DUOX2/ROS/EMT axis that could play a role in colon cancer chemo-resistance and the aggressiveness of this cancer.

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5-Fluorouracil (FU)-resistance is associated with epithelial-mesenchymal transition.

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ROS play a key role in EMT induction in 5-FU resistant colon cancer cells.

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5-FU-resistant cells overexpress the DNA demethylase TET1, which binds to the promoter of the NADPH oxidase DUOX2 and induces its expression.

MicroRNA-142-3p inhibits high-glucose-induced endothelial-to-mesenchymal transition through targeting TGF-β1/Smad pathway in primary human aortic endothelial cells

Myocardial fibrosis is an important pathological feature of diabetic cardiomyopathy (DCM) and endothelial-to-mesenchymal transition (EndMT) is an essential process for myocardial fibrosis. Recent studies have demonstrated an association between miRs and DCM. Therefore, the aim of this study is to investigate the role and the mechanism of miRNAs in the process of EndMT. We simulated the conditions occurring in EndMT by application of high glucose in primary human aortic endothelial cells (HAECs). Firstly, we compared the expression profiles of miRNAs in HAECs with or without HG treatment using microarray. Then, after addition of miR-142-3p mimics, the expression levels of EndMT markers were assessed by qRT-PCR and Western Blot. Moreover, bioinformatics analysis and luciferase assay were used to confirm the direct regulation of miR-142-3p to TGF-β1. Furthermore, the role of TGF-β1 in the inhibitory effect of miR-142-3p on EndMT was evaluated. In addition, the expressions of TGF-β1/Smad signaling signatures were measured by Western Blot. MiR-142-3p screened by miRNA microarray was significantly down-regulated in HAECs under HG stimulation in a dose and time dependent manner. Subsequently, we found that overexpression of miR-142-3p could inhibit HG-induced EndMT, as evidenced by decreased α-SMA and vimentin expression, and increased CD31 and VE-cadherin expression. Of note, transforming growth factor beta 1 (TGF-β1), one of the molecular mediators implicated in the progression of EndMT, was confirmed to be downstream target gene of miR-142-3p in HAECs. Moreover, TGF-β1 overexpression remarkably abolished the inhibitory effects of miR-142-3p overexpression on HG induced EndMT. Finally, miR-142-3p also mediated its anti-EndMT action by inactivation of TGF-β1/Smad pathway, as demonstrated by downregulation of TGF-β1, phospho-Smad2 and phospho-Smad2. Our findings demonstrated that miR-142-3p could attenuate HG-induced EndMT in HAECs, the mechanism of which may be at least partly through blocking TGF-β1/Smad signaling pathway. This might provide a potential therapeutic target for DCM in future.

AT-RVD1 repairs mouse lung after cigarette smoke-induced emphysema via downregulation of oxidative stress by NRF2/KEAP1 pathway

Long-term exposure to cigarette smoke (CS) results in alveolar parenchyma destruction due to chronic inflammatory response and the imbalance between oxidants and antioxidants, and proteases and antiproteases. Emphysema is the main symptom of chronic obstructive pulmonary disease. Current treatment focuses on relieving respiratory symptoms, and inflammation resolution failure is an important pathophysiological element of the disease. Specialized pro-resolving mediators (SPMs) synthesized endogenously during resolution processes demonstrated beneficial effects in murine models of airway inflammation. Here, we aimed to test the SPM AT-RvD1 in a murine model of CS-induced emphysema. AT-RvD1 restored elastic fibers and lung morphology, with reduction in MMP-3, neutrophils, and myeloperoxidase activity and increases in macrophages and IL-10 levels. AT-RvD1 also decreased levels of oxidative stress markers and ROS via upregulation of the Nrf2/Keap1 pathway. Therefore, we suggest that AT-RvD1 causes pro-resolutive action in our murine model of CS-induced emphysema by upregulation of the Nrf2/Keap1 pathway.

Synergistic effect of nutlin-3 combined with aspirin in hepatocellular carcinoma HepG2 cells through activation of Bcl-2/Bax signaling pathway

Aspirin as an antitumor drug has been studied in various malignancies with regards to its effects on apoptosis, proliferation, metastasis and senescence of tumor cells. However, the clinical application is limited by its side effects. Nutlin-3 is a novel antitumor compound, which has not been clinically approved. The present study investigated the value of combining aspirin and nutlin-3 on hepatocellular carcinoma (HCC) cells. MTT was performed to detect the proliferation of HepG2 cells treated with aspirin or/and nutlin-3. Transwell invasion assays were performed to estimate the invasion ability of HepG2 cells treated with aspirin or/and nutlin-3. Then the apoptotic analysis of HepG2 cells evaluated the synergistic effect of aspirin and nutlin-3. Apoptosis markers, including B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), caspase-3, caspase-8 and caspase-9 were estimated by western blot analysis at various time points. In addition, a Xenograft mouse model was established by infection with HepG2 cells, and aspirin and/or nutlin-3 was administrated to verify the anti-apoptotic effect of the two drugs in vivo. A high dose of aspirin and nutlin-3 inhibit the proliferation and apoptosis of HepG2 cells. The antitumor effect was enhanced with the combined treatment of the two drugs, particularly in the group with a low concentration of aspirin and nutlin-3. Nutlin-3 was able to increase the level of Bax in HepG2 cells treated with aspirin significantly after treatment for 8 h. When treated with a low concentration of aspirin and nutlin-3, the level of Bax in HepG2 cells was enhanced for 2 h. In the animal model, tumor volume and tumor angiogenesis were significantly decreased in combination group compared with other groups (P<0.01). Although there were side effects in the group treated with aspirin alone, no side effects were observed in the combination group. Nutlin-3 enhanced the apoptotic effect of a low dose of aspirin by upregulating Bax expression in the HepG2 cell line and in vivo. The synergistic effect of nutlin-3 in aspirin antitumor therapy contributed to diminishing the dose of aspirin required and decreased the occurrence of adverse drug events in HCC through targeting the Bcl-2/Bax signaling pathway.

Salvianolic Acid A, a Component of Salvia miltiorrhiza, Attenuates Endothelial-Mesenchymal Transition of HPAECs Induced by Hypoxia

Salvianolic acid A (SAA), a polyphenols acid, is a bioactive ingredient from a traditional Chinese medicine called Dan shen (Salvia Miltiorrhiza Bunge). According to previous studies, it was shown to have various effects such as anti-oxidative stress, antidiabetic complications and antipulmonary hypertension. This study aimed to investigate the effect of SAA on pulmonary arterial endothelial-mesenchymal transition (EndoMT) induced by hypoxia and the underlying mechanisms. Primary cultured human pulmonary arterial endothelial cells (HPAECs) were exposed to 1% O₂ for 48[Formula: see text]h with or without SAA treatment. SAA treatment improved the morphology of HPAECs and inhibited the cytoskeleton remodeling. A total of 3[Formula: see text][Formula: see text]M SAA reduced migration distances from 262.2[Formula: see text][Formula: see text]m to 198.4[Formula: see text][Formula: see text]m at 24[Formula: see text]h and 344.8[Formula: see text][Formula: see text]m to 109.3[Formula: see text][Formula: see text]m at 48[Formula: see text]h. It was observed that the production of ROS in cells was significantly reduced by the treatment of 3[Formula: see text][Formula: see text]M SAA. Meanwhile, SAA alleviated the loss of CD31 and slightly inhibited the expression of [Formula: see text]-SMA. The mechanisms study shows that SAA treatment increased the phosphorylation levels of Smad1/5, but inhibited that of Smad2/3. Furthermore, SAA attenuated the phosphorylation levels of ERK and Cofilin, which were enhanced by hypoxia. Based on these results, our study indicated that SAA treatment can protect HPAECs from endoMT induced by hypoxia, which may perform via the inhibition on ROS production and further through the downstream effectors of BMPRs or TGF[Formula: see text]R including Smads, ERK and ROCK/cofilin pathways.

Activation of Nrf2 Attenuates Pulmonary Vascular Remodeling via Inhibiting Endothelial-to-Mesenchymal Transition: an Insight from a Plant Polyphenol

The endothelial-to-mesenchymal transition (EndMT) has been demonstrated to be involved in pulmonary vascular remodeling. It is partly attributed to oxidative and inflammatory stresses in endothelial cells. In current study, we conducted a series of experiments to clarify the effect of salvianolic acid A (SAA), a kind of polyphenol compound, in the process of EndMT in human pulmonary arterial endothelial cells and in vivo therapeutic efficacy on vascular remodeling in monocrotaline (MCT)-induced EndMT. EndMT was induced by TGFβ1 in human pulmonary arterial endothelial cells (HPAECs). SAA significantly attenuated EndMT, simultaneously inhibited cell migration and reactive oxygen species (ROS) formation. In MCT-induced pulmonary arterial hypertension (PAH) model, SAA improved vascular function, decreased TGFβ1 level and inhibited inflammation. Mechanistically, SAA stimulated Nrf2 translocation and subsequent heme oxygenase-1 (HO-1) up-regulation. The effect of SAA on EndMT in vitro was abolished by ZnPP, a HO-1 inhibitor. In conclusion, this study indicates a deleterious impact of oxidative stress on EndMT. Polyphenol antioxidant treatment may provide an adjunctive action to alleviate pulmonary vascular remodeling via inhibiting EndMT.

The mechanism of TGF-β/miR-155/c-Ski regulates endothelial-mesenchymal transition in human coronary artery endothelial cells

Human coronary artery endothelial cells (HCAECs) have the potential to undergo fibrogenic endothelial–mesenchymal transition (EndMT), which results in matrix-producing fibroblasts and thereby contributes to the pathogenesis of cardiac fibrosis. Recently, the profibrotic cytokine transforming growth factor-β (TGF-β) is shown to be the crucial pathogenic driver which has been verified to induce EndMT. C-Ski is an important regulator of TGF-β signaling. However, the detailed role of c-Ski and the molecular mechanisms by which c-Ski affects TGF-β-induced EndMT in HCAECs are not largely elucidated. In the present study, we treated HCAECs with TGF-β of different concentrations to induce EndMT. We found that overexpression of c-Ski in HCAECs either blocked EndMT via hindering Vimentin, Snail, Slug, and Twist expression while enhancing CD31 expression, with or without TGF-β treatment. In contrast, suppression of c-Ski further enhanced EndMT. Currently, miRNA expression disorder has been frequently reported associating with cardiac fibrosis. By using online tools, we regarded miR-155 as a candidate miRNA that could target c-Ski, which was verified using luciferase assays. C-Ski expression was negatively regulated by miR-155. TGF-β-induced EndMT was inhibited by miR-155 silence; the effect of TGF-β on Vimentin, CD31, Snail, Slug, and Twist could be partially restored by miR-155. Altogether, these findings will shed light on the role and mechanism by which miR-155 regulates TGF-β-induced HCAECs EndMT via c-Ski to affect cardiac fibrosis, and miR-155/c-Ski may represent novel biomarkers and therapeutic targets in the treatment of cardiac fibrosis.

Endothelial to mesenchymal transition in the cardiovascular system

Endothelial to mesenchymal transition (EndMT) is a special type of epithelial to mesenchymal transition. It is a process that is characterized by the loss of features of endothelial cells and acquisition of specific markers of mesenchymal cells. A variety of stimuli, such as inflammation, growth factors, and hypoxia, regulate EndMT through various signaling pathways and intracellular transcription factors. It has been demonstrated that epigenetic modifications are also involved in this process. Recent studies have identified the essential role of EndMT in the cardiovascular system. EndMT contributes to steps in cardiovascular development, such as cardiac valve formation and septation, as well as the pathogenesis of various cardiovascular disorders, such as congenital heart disease, myocardial fibrosis, myocardial infarction and pulmonary arterial hypertension. Thus, comprehensive understanding of the underlying mechanisms of EndMT will provide novel therapeutic strategies to overcome congenital heart disease due to abnormal development and other cardiovascular diseases. This review will focus on summarizing the currently understood signaling pathways and epigenetic modifications involved in the regulation of EndMT and the role of EndMT in pathophysiological conditions of the cardiovascular system.

Role of endothelial-to-mesenchymal transition induced by TGF-β1 in transplant kidney interstitial fibrosis

Chronic allograft dysfunction (CAD) induced by kidney interstitial fibrosis is the main cause of allograft failure in kidney transplantation. Endothelial‐to‐mesenchymal transition (EndMT) may play an important role in kidney fibrosis. We, therefore, undertook this study to characterize the functions and potential mechanism of EndMT in transplant kidney interstitial fibrosis. Proteins and mRNAs associated with EndMT were examined in human umbilical vein endothelial cells (HUVECs) treated with transforming growth factor‐beta1 (TGF‐β1) at different doses or at different intervals with western blotting, qRT‐PCR and ELISA assays. Cell motility and migration were evaluated with motility and migration assays. The mechanism of EndMT induced by TGF‐β1 was determined by western blotting analysis of factors involved in various canonical and non‐canonical pathways. In addition, human kidney tissues from control and CAD group were also examined for these proteins by HE, Masson's trichrome, immunohistochemical, indirect immunofluorescence double staining and western blotting assays. TGF‐β1 significantly promoted the development of EndMT in a time‐dependent and dose‐dependent manner and promoted the motility and migration ability of HUVECs. The TGF‐β/Smad and Akt/mTOR/p70S6K signalling pathways were found to be associated with the pathogenesis of EndMT induced by TGF‐β1, which was also proven in vivo by the analysis of specimens from the control and CAD groups. EndMT may promote transplant kidney interstitial fibrosis by targetting the TGF‐β/Smad and Akt/mTOR/p70S6K signalling pathways, and hence, result in the development of CAD in kidney transplant recipients.

Hypoxia-induced endothelial-mesenchymal transition is associated with RASAL1 promoter hypermethylation in human coronary endothelial cells

Cardiac fibrosis is integral in chronic heart disease, and one of the cellular processes contributing to cardiac fibrosis is endothelial-to-mesenchymal transition (EndMT). We recently found that hypoxia efficiently induces human coronary artery endothelial cells (HCAEC) to undergo EndMT through a hypoxia inducible factor-1α (HIF1α)-dependent pathway. Promoter hypermethylation of Ras-Gap-like protein 1 (RASAL1) has also been recently associated with EndMT progression and cardiac fibrosis. Our findings suggest that HIF1α and transforming growth factor (TGF)/SMAD signalling pathways synergistically regulate hypoxia-induced EndMT through both DNMT3a-mediated hypermethylation of RASAL1 promoter and direct SNAIL induction. The findings indicate that multiple cascades may be activated simultaneously to mediate hypoxia-induced EndMT.