Endothelial to mesenchymal transition contributes to arsenic-trioxide-induced cardiac fibrosis

Diosgenin alleviates arsenic trioxide induced cardiac fibrosis by inhibiting endothelial mesenchymal transition

BACKGROUD

Arsenic trioxide (ATO), the first-line drug in treating acute premyelogenous leukemia, has the profound side effect of inducing endothelial mesenchymal transition (EndMT) and causing cardiac fibrosis. Diosgenin (DIO), a pharmaceutical compound found in Paris polyphylla, exhibits promising potential in safeguarding cardiovascular health by mitigating EndMT.

PURPOSE

This study aims to explore the role and mechanism of DIO in ATO-induced myocardial fibrosis to provide a novel therapeutic agent for ATO-induced cardiac fibrosis.

METHODS

Wistar rats were given DIO by gavage and ATO by tail vein. Cardiac function and fibrosis were evaluated by echocardiography and Masson's trichrome staining in rats. Human aortic endothelial cells (HAECs) were utilized to analyze ATO-induced EndMT in vitro. The cytoskeleton of HAECs was visualized using F-actin staining to observe cell morphology, while Dil-Ac-LDL staining was employed to assess cell functionality. EndMT-related factors (CD31 and α-SMA), glucocorticoid receptor (GR) and interleukin-6 (IL-6) were detected by immunofluorescence and Western blot in vivo and in vitro. Furthermore, GR was knocked down by si-GR, and IL-6 was blocked by IL-6 neutralizing antibody to verify their role in the effect of DIO on ATO-induced EndMT in HAECs.

RESULTS

DIO exhibited significant efficacy in ATO-induced damage to both cardiac diastolic and systolic function, along with mitigating cardiac fibrosis. Additionally, DIO alleviated the loss of cytoskeletal anisotropy and enhanced the uptake of Dil-Ac-LDL in HAECs. Furthermore, it reversed the ATO-induced downregulation of endothelial-specific markers CD31 and GR, while suppressing the upregulation of mesenchymal markers α-SMA and IL-6, both in vivo and in vitro. Notably, the protective effect of DIO was compromised upon knockdown of GR, which also led to a reversal of DIO-induced IL-6 downregulation. Furthermore, the neutralization of IL-6 with specific antibodies abolished the ATO-induced changes related to EndMT.

CONCLUSION

In this study, we clarified the protective effect of DIO on ATO-induced myocardial fibrosis against EndMT via the GR/IL-6 axis for the first time and provided a potential therapeutic agent for preventing heart damage caused by ATO.

Endothelial-to-Mesenchymal Transition in Human and Murine Models of Congenital Diaphragmatic Hernia

INTRODUCTION

Congenital diaphragmatic hernia (CDH) is a complex congenital disorder, characterized by pulmonary hypertension (PH) and hypoplasia. PH secondary to CDH (CDH-PH) features devastating morbidity and mortality (25-30%) among neonates. An unmet need is determining mechanisms triggering CDH-PH to save infants. Prior data suggest abnormal remodeling of the pulmonary vascular extracellular matrix (ECM), presumed to be driven by endothelial-to-mesenchymal transition (EndoMT), hinders postnatal vasodilation and limits anti-PH therapy in CDH. There are limited data on the role of EndoMT in CDH-PH.

METHODS

The purpose of the study was to investigate how EndoMT contributes to CDH-PH by identifying cells undergoing EndoMT noted by alpha smooth muscle actin (α-SMA) expression in human umbilical vein endothelial cells (HUVECs) and lung tissue obtained from murine pups using the nitrofen model. N = 8 CDH, N = 8 control HUVECs were stained for α-SMA and CD31 after being exposed for 24 h to TGFB, a known EndoMT promoter. N = 8 nitrofen, N = 8 control murine pup lungs were also stained for α-SMA and CD31. α-SMA and CD31 expression was quantified in HUVECs and murine tissue using Fiji imaging software and normalized to the total number of cells per slide noted by DAPI staining.

RESULTS

CDH HUVECs demonstrated a 1.1-fold increase in α-SMA expression (p = 0.02). The murine model did not show statistical significance between nitrofen and control pup lungs; however, there was a 0.4-fold increase in α-SMA expression with a 0.8-fold decrease in CD31 expression in the nitrofen pup lungs when compared to controls.

CONCLUSION

These results suggest that EndoMT could potentially play a role in the ECM remodeling seen in CDH-PH.

SIRT1 mediates the inhibitory effect of Dapagliflozin on EndMT by inhibiting the acetylation of endothelium Notch1

BACKGROUND

Endothelial-mesenchymal transition (EndMT) plays a crucial role in promoting myocardial fibrosis and exacerbating cardiac dysfunction. Dapagliflozin (DAPA) is a sodium-glucose-linked transporter 2 (SGLT-2) inhibitor that has been shown to improve cardiac function in non-diabetic patients with heart failure (HF). However, the precise mechanisms by which DAPA exerts its beneficial effects are yet to be fully elucidated.

METHODS

Isoproterenol (ISO) was used to generate a HF model in mice. For in vitro experiments, we used TGF-β1-stimulated human umbilical vein endothelial cells (HUVECs) and mouse aortic endothelial cells (MAECs).

RESULTS

Both our in vivo and in vitro results showed that EndMT occurred with decreased SIRT1 (NAD+-dependent deacetylase) protein expression, which could be reversed by DAPA therapy. We found that the protective effect of DAPA was significantly impaired upon SIRT1 inhibition. Mechanistically, we observed that SIRT1 phosphorylation, a required modification for its ubiquitination and degradation, was reduced by DAPA treatment, which induces the nucleus translocation of SIRT1 and promotes its binding to the active intracellular domain of Notch1 (NICD). This interaction led to the deacetylation and degradation of NICD, and the subsequent inactivation of the Notch1 signaling pathway which contributes to ameliorating EndMT.

CONCLUSIONS

Our study revealed that DAPA can attenuate EndMT induced by ISO in non-diabetic HF mice. This beneficial effect is achieved through SIRT1-mediated deacetylation and degradation of NICD. Our findings provide greater insight into the underlying mechanisms of the therapeutic effects of DAPA in non-diabetic HF.

Endothelial activation and fibrotic changes are impeded by laminar flow-induced CHK1-SENP2 activity through mechanisms distinct from endothelial-to-mesenchymal cell transition

Background

The deSUMOylase sentrin-specific isopeptidase 2 (SENP2) plays a crucial role in atheroprotection. However, the phosphorylation of SENP2 at T368 under disturbed flow (D-flow) conditions hinders its nuclear function and promotes endothelial cell (EC) activation. SUMOylation has been implicated in D-flow-induced endothelial-to-mesenchymal transition (endoMT), but the precise role of SENP2 in counteracting this process remains unclear.

Method

We developed a phospho-specific SENP2 S344 antibody and generated knock-in (KI) mice with a phospho-site mutation of SENP2 S344A using CRISPR/Cas9 technology. We then investigated the effects of SENP2 S344 phosphorylation under two distinct flow patterns and during hypercholesteremia (HC)-mediated EC activation.

Result

Our findings demonstrate that laminar flow (L-flow) induces phosphorylation of SENP2 at S344 through the activation of checkpoint kinase 1 (CHK1), leading to the inhibition of ERK5 and p53 SUMOylation and subsequent suppression of EC activation. We observed a significant increase in lipid-laden lesions in both the aortic arch (under D-flow) and descending aorta (under L-flow) of female hypercholesterolemic SENP2 S344A KI mice. In male hypercholesterolemic SENP2 S344A KI mice, larger lipid-laden lesions were only observed in the aortic arch area, suggesting a weaker HC-mediated atherogenesis in male mice compared to females. Ionizing radiation (IR) reduced CHK1 expression and SENP2 S344 phosphorylation, attenuating the pro-atherosclerotic effects observed in female SENP2 S344A KI mice after bone marrow transplantation (BMT), particularly in L-flow areas. The phospho-site mutation SENP2 S344A upregulates processes associated with EC activation, including inflammation, migration, and proliferation. Additionally, fibrotic changes and up-regulated expression of EC marker genes were observed. Apoptosis was augmented in ECs derived from the lungs of SENP2 S344A KI mice, primarily through the inhibition of ERK5-mediated expression of DNA damage-induced apoptosis suppressor (DDIAS).

Summary

In this study, we have revealed a novel mechanism underlying the suppressive effects of L-flow on EC inflammation, migration, proliferation, apoptosis, and fibrotic changes through promoting CHK1-induced SENP2 S344 phosphorylation. The phospho-site mutation SENP2 S344A responds to L-flow through a distinct mechanism, which involves the upregulation of both mesenchymal and EC marker genes.

Cellular and Molecular Mechanisms of Intestinal Fibrosis

Intestinal fibrosis associated stricture is a common complication of inflammatory bowel disease usually requiring endoscopic or surgical intervention. Effective anti-fibrotic agents aiming to control or reverse intestinal fibrosis are still unavailable. Thus, clarifying the mechanism underpinning intestinal fibrosis is imperative. Fibrosis is characterized by an excessive accumulation of extracellular matrix (ECM) proteins at the injured sites. Multiple cellular types are implicated in fibrosis development. Among these cells, mesenchymal cells are major compartments that are activated and then enhance the production of ECM. Additionally, immune cells contribute to the persistent activation of mesenchymal cells and perpetuation of inflammation. Molecules are messengers of crosstalk between these cellular compartments. Although inflammation is necessary for fibrosis development, purely controlling intestinal inflammation cannot halt the development of fibrosis, suggesting that chronic inflammation is not the unique contributor to fibrogenesis. Several inflammation-independent mechanisms including gut microbiota, creeping fat, ECM interaction, and metabolic reprogramming are involved in the pathogenesis of fibrosis. In the past decades, substantial progress has been made in elucidating the cellular and molecular mechanisms of intestinal fibrosis. Here, we summarized new discoveries and advances of cellular components and major molecular mediators that are associated with intestinal fibrosis, aiming to provide a basis for exploring effective anti-fibrotic therapies in this field.

Endothelial-to-Mesenchymal Transition: Potential Target of Doxorubicin-Induced Cardiotoxicity

The use of chemotherapeutic agents is becoming more frequent as the proportion of new oncology patients increases worldwide, with prolonged survival after treatment. As one of the most popular chemotherapy drugs, doxorubicin plays a substantial role in the treatment of tumors. Unfortunately, the use of doxorubicin is associated with several adverse effects, particularly severe cardiotoxicity that can be life-threatening, which greatly limits its clinical use. For decades, scientists have tried to explore many cardioprotective agents and therapeutic approaches, but their efficacy remains controversial, and some drugs have even brought about significant adverse effects. The concrete molecular mechanism of doxorubicin-induced cardiotoxicity is still to be unraveled, yet endothelial damage is gradually being identified as an important mechanism triggering the development and progression of doxorubicin-induced cardiotoxicity. Endothelial-to-mesenchymal transition (EndMT), a fundamental process regulating morphogenesis in multicellular organisms, is recognized to be associated with endothelial damage repair and acts as an important factor in the progression of cardiovascular diseases, tumors, and rheumatic immune diseases. Mounting evidence suggests that endothelial-mesenchymal transition may play a non-negligible role in doxorubicin-induced cardiotoxicity. In this paper, we reviewed the molecular mechanisms and signaling pathways of EndMT and outlined the molecular mechanisms of doxorubicin-induced cardiotoxicity and the current therapeutic advances. Furthermore, we summarized the basic principles of doxorubicin-induced endothelial-mesenchymal transition that lead to endothelial dysfunction and cardiotoxicity, aiming to provide suggestions or new ideas for the prevention and treatment of doxorubicin-induced endothelial and cardiac injury.

Distinct tissue niches direct lung immunopathology via CCL18 and CCL21 in severe COVID-19

Prolonged lung pathology has been associated with COVID-19, yet the cellular and molecular mechanisms behind this chronic inflammatory disease are poorly understood. In this study, we combine advanced imaging and spatial transcriptomics to shed light on the local immune response in severe COVID-19. We show that activated adventitial niches are crucial microenvironments contributing to the orchestration of prolonged lung immunopathology. Up-regulation of the chemokines CCL21 and CCL18 associates to endothelial-to-mesenchymal transition and tissue fibrosis within these niches. CCL21 over-expression additionally links to the local accumulation of T cells expressing the cognate receptor CCR7. These T cells are imprinted with an exhausted phenotype and form lymphoid aggregates that can organize in ectopic lymphoid structures. Our work proposes immune-stromal interaction mechanisms promoting a self-sustained and non-resolving local immune response that extends beyond active viral infection and perpetuates tissue remodeling.

Endothelial-mesenchymal transition as a novel mechanism for generating myofibroblasts during wound healing and scarring

BACKGROUND

The endothelial-mesenchymal transition (EndMT) is an important mechanism in tissue regeneration and the development of organ fibrosis. Whether EndMT occurs in wound healing and scarring remains unknown.

MATERIALS AND METHODS

The isolated cells from the normal dermal tissue and the wound tissue of mouse with full-thickness skin wound, and human scar tissue sections were performed with CD31/factorVII and α-SMA immunohistochemical staining and H and E staining. The ratio of factor VII or CD31/α-SMA double-positive cells in factor VII-positive cells was assessed in the isolated cells and in scar tissues.

RESULTS

In this study, we found that approximately 27-60% of ECs coexpressed VII factor and α-SMA in the isolated cells from the wound tissues of mice, which was significantly higher than that of normal dermal tissue cells. Accordingly, the number of CD31/α-SMA double-positive cells in mouse wound tissue sections was also significantly more than that in normal dermal tissue sections. In scar tissues, in addition to high-density microvessels, a large number of proliferative ECs in scar strama and CD31/α-SMA double-positive cells were also found. Approximately 46.82 to 84.11% of ECs and 68.77 to 95.25% of myofibroblasts coexpressed VII factor and α-SMA, and these two values in hypertrophic scars were significantly higher than those in keloids.

CONCLUSION

These results confirmed that ECs might contribute to the emergence of myofibroblasts in the wound and scar tissue via the process of EndMT.

Arsenic exposure promotes the emergence of cardiovascular diseases

A large number of studies conducted in the past decade 2010-2020 refer to the impact of arsenic (As) exposure on cardiovascular risk factors. The arsenic effect on humans is complex and mainly depends on the varying individual susceptibilities, its numerous toxic expressions and the variation in arsenic metabolism between individuals. In this review we present relevant data from studies which document the association of arsenic exposure with various biomarkers, the effect of several genome polymorphisms on arsenic methylation and the underling molecular mechanisms influencing the cardiovascular pathology. The corresponding results provide strong evidence that high and moderate-high As intake induce oxidative stress, inflammation and vessel endothelial dysfunction that are associated with increased risk for cardiovascular diseases (CVDs) and in particular hypertension, myocardial infarction, carotid intima-media thickness and stroke, ventricular arrhythmias and peripheral arterial disease. In addition, As exposure during pregnancy implies risks for blood pressure abnormalities among infants and increased mortality rates from acute myocardial infarction during early adulthood. Low water As concentrations are associated with increased systolic, diastolic and pulse pressure, coronary heart disease and incident stroke. For very low As concentrations the relevant studies are few. They predict a risk for myocardial infarction, stroke and ischemic stroke and incident CVD, but they are not in agreement regarding the risk magnitude.

Limb-Bud and Heart (LBH) Upregulation in Cardiomyocytes under Hypoxia Promotes the Activation of Cardiac Fibroblasts via Exosome Secretion

The activation of cardiac fibroblasts (CFs) after myocardial infarction (MI) is essential for post-MI infarct healing, during which the regulation of transforming growth factor beta1 (TGF-β1) signaling is predominant. We have demonstrated that TGF-β1-mediated upregulation of LBH contributes to post-MI CF activation via modulating αB-crystallin (CRYAB), after being upregulated by TGF-β1. In this study, the effect of LBH-CRYAB signaling on the cardiac microenvironment via exosome communication and the corresponding mechanisms were investigated. The upregulation of LBH and CRYAB was verified in both cardiomyocytes (CMs) and CFs in hypoxic, post-MI peri-infarct tissues. CM-derived exosomes were isolated and identified, and LBH distribution was elevated in exosomes derived from LBH-upregulated CMs under hypoxia. Treatment with LBH+ exosomes promoted cellular proliferation, differentiation, and epithelial-mesenchymal transition-like processes in CFs. Additionally, in primary LBH^KO CFs, western blotting showed that LBH knockout partially inhibited TGF-β1-induced CF activation, while LBH-CRYAB signaling affected TGF-β1 expression and secretion through a positive feedback loop. The administration of a Smad3 phosphorylation inhibitor to LBH^KO CFs under TGF-β1 stimulation indicated that Smad3 phosphorylation partially accounted for TGF-β1-induced LBH upregulation. In conclusion, LBH upregulation in CMs in post-MI peri-infarct areas correlated with a hypoxic cardiac microenvironment and led to elevated exosomal LBH levels, promoting the activation of recipient CFs, which brings new insights into the studies and therapeutic strategies of post-MI cardiac repair.

Fibrotic Scar in CNS Injuries: From the Cellular Origins of Fibroblasts to the Molecular Processes of Fibrotic Scar Formation

Central nervous system (CNS) trauma activates a persistent repair response that leads to fibrotic scar formation within the lesion. This scarring is similar to other organ fibrosis in many ways; however, the unique features of the CNS differentiate it from other organs. In this review, we discuss fibrotic scar formation in CNS trauma, including the cellular origins of fibroblasts, the mechanism of fibrotic scar formation following an injury, as well as the implication of the fibrotic scar in CNS tissue remodeling and regeneration. While discussing the shared features of CNS fibrotic scar and fibrosis outside the CNS, we highlight their differences and discuss therapeutic targets that may enhance regeneration in the CNS.

An In Vitro Platform to Study Reversible Endothelial-to-Mesenchymal Transition

Endothelial cells can acquire a mesenchymal phenotype in response to external stimuli through both mechanical and biological factors, using a process known as endothelial-to-mesenchymal (EndoMT) transition. EndoMT is characterized by the decrease in endothelial characteristics, increase in mesenchymal markers, and morphological changes. It has been recognized not only during development but also in different pathological conditions including organ/tissue fibrosis in adults. The ability to modulate the EndoMT process could have a therapeutic potential in many fibrotic diseases. An in vitro method is presented here to induce EndoMT with Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME) and angiotensin II (Ang II) followed by a protocol to study the reversibility of EndoMT. Using this method, we furnish evidence that the combination of L-NAME and Ang II can stimulate EndoMT in Human umbilical vascular endothelial cells (HUVECs) and this process can be reversed as observed using endothelial functionality assays. This method may serve as a model to screen and identify potential pharmacological molecules to target and regulate the EndoMT process, with applications in drug discovery for human diseases.

Honokiol attenuate the arsenic trioxide-induced cardiotoxicity by reducing the myocardial apoptosis

Despite advantages of arsenic trioxide (ATO) in oncological practice, its clinical applications have been hampered by severe cardiotoxicity. The general mechanism of ATO-induced cardiotoxicity has been attributed to its damage to mitochondria, resulting in cardiac remodeling. Honokiol (HKL) is a naturally occurring compound derived from Magnolia bark. Previous studies have demonstrated that HKL exerts cardio-protective effects on ischemia/reperfusion (I/R) or chemical-induced cardiotoxicity by counteracting the toxic effects on mitochondria. The present study was conducted to investigate whether HKL pretreatment protects against ATO-induced cardiac oxidative damage and cell death. For the in vitro study, we evaluated the effects of ATO and/or Honokiol on reactive oxygen species (ROS) production and apoptosis induction in primary cultured cardiomyocytes; for the in vivo study, BALB/c mice were administrated with ATO and/or HKL for a period of 4 weeks, myocardial apoptosis, cardiac function, and cardiac remodeling (cardiac hypertrophy and cardiac fibrosis) were assessed at the end of administration. Our results demonstrated Honokiol pretreatment alleviated the ATO-induced boost in ROS concentration and the following apoptosis induction in primary cultured cardiomyocytes. In the mouse model, Honokiol pretreatment ameliorated ATO-induced myocardial apoptosis, cardiac dysfunction, and cardiac remodeling. Collectively, these results indicated that Honokiol provide a protection against ATO-induced cardiotoxicity by reducing mitochondrial damage. In addition, given that Honokiol has shown considerable suppressive effects on leukemia cells, our data also imply that ATO and Honokiol combination may possibly be a superior avenue in leukemia therapy.

Deciphering the Dynamic Molecular Program of Radiation-Induced Endothelial Senescence

PURPOSE

Radiation-induced cellular senescence is a double-edged sword, acting as both a tumor suppression process limiting tumor proliferation, and a crucial process contributing to normal tissue injury. Endothelial cells play a role in normal tissue injury after radiation therapy. Recently, a study observed an accumulation of senescent endothelial cells (ECs) around radiation-induced lung focal lesions following stereotactic radiation injury in mice. However, the effect of radiation on EC senescence remains unclear because it depends on dose and fractionation, and because the senescent phenotype is heterogeneous and dynamic.

METHODS AND MATERIALS

Using a systems biology approach in vitro, we deciphered the dynamic senescence-associated transcriptional program induced by irradiation.

RESULTS

Flow cytometry and single-cell RNA sequencing experiments revealed the heterogeneous senescent status of irradiated ECs and allowed to deciphered the molecular program involved in this status. We identified the Interleukin-1 signaling pathway as a key player in the radiation-induced premature senescence of ECs, as well as the endothelial-to-mesenchymal transition process, which shares strong hallmarks of senescence.

CONCLUSIONS

Our work provides crucial information on the dynamics of the radiation-induced premature senescence process, the effect of the radiation dose, as well as the molecular program involved in the heterogeneous senescent status of ECs.

Endocardial Endothelial Dysfunction and Unknown Polymorphic Composite Accumulation in Heart Failure

The accumulation of unknown polymorphic composites in the endocardium damages the endocardial endothelium (EE). However, the composition and role of unknown polymorphic composites in heart failure (HF) progression remain unclear. Here, we aimed to explore composite deposition during endocardium damage and HF progression. Adult male Sprague–Dawley rats were divided into two HF groups—angiotensin II-induced HF and left anterior descending artery ligation-induced HF. Heart tissues from patients who had undergone coronary artery bypass graft surgery (non-HF) and those with dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) were collected. EE damage, polymorphic unknown composite accumulation, and elements in deposits were examined. HF progression reduced the expression of CD31 in the endocardium, impaired endocardial integrity, and exposed the myofibrils and mitochondria. The damaged endocardial surface showed the accumulation of unknown polymorphic composites. In the animal HF model, especially HF caused by myocardial infarction, the weight and atomic percentages of O, Na, and N in the deposited composites were significantly higher than those of the other groups. The deposited composites in the human HF heart section (DCM) had a significantly higher percentage of Na and S than the other groups, whereas the percentage of C and Na in the DCM and ICM groups was significantly higher than those of the control group. HF causes widespread EE dysfunction, and EndMT was accompanied by polymorphic composites of different shapes and elemental compositions, which further damage and deteriorate heart function.

Co-exposure to inorganic arsenic and fluoride prominently disrupts gut microbiota equilibrium and induces adverse cardiovascular effects in offspring rats

Co-exposure to inorganic arsenic (iAs) and fluoride (F^-) and their collective actions on cardiovascular systems have been recognized as a global public health concern. Emerging studies suggest an association between the perturbation of gut bacterial microbiota and adverse cardiovascular effects (CVEs), both of which are the consequence of iAs and F^- exposure in human and experimental animals. The aim of this study was to fill the gap of understanding the relationship among co-exposure to iAs and F^-, gut microbiota perturbation, and adverse CVEs. We systematically assessed cardiac morphology and functions (blood pressure, echocardiogram, and electrocardiogram), and generated gut microbiota profiles using 16S rRNA gene sequencing on rats exposed to iAs (50 mg/L NaAsO₂), F^- (100 mg/L NaF) or combined iAs and F^- (50 mg/L NaAsO₂ + 100 mg/L NaF), in utero and during early postnatal periods (postnatal day 90). Correlation analysis was then performed to examine relationship between significantly altered microbiota and cardiac performance indices. Our results showed that co-exposure to iAs and F^- resulted in more prominent effects in CVEs and perturbation of gut microbiota profiles, compared to iAs or F^- treatment alone. Furthermore, nine bacterial genera (Adlercreutzia, Clostridium sensu stricto 1, Coprococcus 3, Romboutsia, [Bacteroides] Pectinophilus group, Lachnospiraceae NC2004 group, Desulfovibrio, and two unidentified genera in Muribaculaceae and Ruminococcaceae family), which differed significantly in relative abundance between control and iAs and F^- co-exposure group, were strongly correlated with the higher risk of CVEs (correlation coefficient = 0.70-0.88, p < 0.05). Collectively, these results suggest that co-exposure to iAs and F^- poses a higher risk of CVEs, and the part of the mode of action is potentially through inducing gut microbiota disruption, and the strong correlations between them indicate a high potential for the development of novel microbiome-based biomarkers of iAs and/or F^- associated CVEs.

Tumor necrosis factor superfamily 14 is critical for the development of renal fibrosis

Objective: Tumor necrosis factor superfamily protein 14 (TNFSF14) was recently identified as a risk factor in some fibrosis diseases. However, the role of TNFSF14 in renal fibrosis pathogenesis remains unknown.

Results: It was found that TNFSF14 levels were significantly increased both in UUO-induced renal fibrotic mice and in patients with fibrotic nephropathy, compared with those in controls. Accordingly, Tnfsf14 deficiency led to a marked reduction in renal fibrosis lesions and inflammatory cytokines expression in the UUO mice. Furthermore, the levels of Sphk1, a critical molecule that causes fibrotic nephropathy, were remarkably reduced in Tnfsf14 KO mice with UUO surgery. In vitro recombinant TNFSF14 administration markedly up-regulated the expression of Sphk1 of primary mouse renal tubular epithelial cells (mTECs).

Conclusion: TNFSF14 is a novel pro-fibrotic factor of renal fibrosis, for which TNFSF14 up-regulates Sphk1 expression, which may be the underlying mechanism of TNFSF14-mediated renal fibrosis.

Methods: We investigated the effect of TNFSF14 on renal fibrosis and the relationship between TNFSF14 and pro-fibrotic factor sphingosine kinase 1 (Sphk1) by using the unilateral urethral obstruction (UUO)-induced mice renal fibrosis as a model and the specimen of patients with fibrosis nephropathy, by Masson trichrome staining, immunohistochemistry, qRT-PCR, and western blot analysis.

Fibrotic Changes and Endothelial-to-Mesenchymal Transition Promoted by VEGFR2 Antagonism Alter the Therapeutic Effects of VEGFA Pathway Blockage in a Mouse Model of Choroidal Neovascularization

Many patients with wet age-related macular degeneration do not respond well to anti- vascular endothelial growth factor A (VEGFA) therapy for choroidal neovascularization (CNV), and the efficacy of anti-VEGFA decreases over time. We investigated the hypothesis that fibrotic changes, in particular via endothelial-to-mesenchymal transition (EndoMT), play a role in CNV and alter the therapeutic effects of VEGFA pathway blockage. Induction of EndoMT of primary human retinal endothelial cells led to a significantly reduced response to VEGFA at the level of gene expression, cellular proliferation, migration, and tube formation. Suppression of EndoMT restored cell responsiveness to VEGFA. In a mouse model of spontaneous CNV, fibrotic changes and EndoMT persisted as the CNV lesions became more established over time. VEGFA receptor-2 (VEGFR2) antagonism further induced fibrosis and EndoMT in the CNV. The combination of VEGFR2 antagonism and fibrosis/EndoMT inhibition was more effective than either individual treatment in reducing CNV. Our data indicate that fibrosis and EndoMT are involved in the progression of CNV, are exacerbated by VEGFR2 inhibition, and could provide an explanation for the reduced efficacy of anti-VEGFA treatment over time.

The New Model of Snail Expression Regulation: The Role of MRTFs in Fast and Slow Endothelial-Mesenchymal Transition

Endothelial–mesenchymal transition (EndMT) is a crucial phenomenon in regulating the development of diseases, including cancer metastasis and fibrotic disorders. The primary regulators of disease development are zinc-finger transcription factors belonging to the Snail family. In this study, we characterized the myocardin-related transcription factor (MRTF)-dependent mechanisms of a human snail promoter regulation in TGF-β-stimulated human endothelial cells. Although in silico analysis revealed that the snail promoter’s regulatory fragment contains one GCCG and two SP1 motifs that could be occupied by MRTFs, the genetic study confirmed that MRTF binds only to SP1 sites to promote snail expression. The more accurate studies revealed that MRTF-A binds to both SP1 elements, whereas MRTF-B to only one (SP1near). Although we found that each MRTF alone is capable of inducing snail expression, the direct cooperation of these proteins is required to reinforce snail expression and promote the late stages of EndMT within 48 hours. Furthermore, genetic and biochemical analysis revealed that MRTF-B alone could induce the late stage of EndMT. However, it requires a prolonged time. Therefore, we concluded that MRTFs might cause EndMT in a fast- and slow-dependent manner. Based on MRTF-dependent Snail upregulation, we recognized that TGF-β1, as an MRTF-B regulator, is involved in slow EndMT induction, whereas TGF-β2, which altered both MRTF-A and MRTF-B expression, promotes a fast EndMT process.

NF-κB pathway activation during endothelial-to-mesenchymal transition in a rat model of doxorubicin-induced cardiotoxicity

Doxorubicin is a commonly used anthracycline chemotherapeutic agent; however, its application is limited owing to its cardiotoxicity. Current clinical treatments cannot efficiently or fully prevent doxorubicin-induced toxicity, primarily because its pathogenesis and mechanisms of action remain unknown. In this study, we established a rat model of chronic doxorubicin-induced cardiotoxicity, in which the severity of cardiac fibrosis and hydroxyproline levels increased in a time-dependent manner. Doxorubicin damaged the mitochondria and blood vessels and induced autophagy. Cells undergoing endothelial-to-mesenchymal transition (EndoMT)and those expressing endothelial cell and myofibroblast markers were simultaneously observed in vitro and in rats treated with doxorubicin. The NF-κB pathway was activated during EndoMT, andp65 and p-p65 were strongly expressed in the nucleus of endothelial cells in vitro. Taken together, these results suggest that vascular injury and cardiac fibrosis are characteristic symptoms of doxorubicin-induced cardiotoxicity. The NF-κB pathway-associated EndoMT may influence the pathogenesis of doxorubicin-induced cardiotoxicity, and the constituents of this pathway may be potential therapeutic targets to prevent the development of this condition.

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 downregulation 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.

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.

Endothelial-to-mesenchymal transition in anticancer therapy and normal tissue damage

Endothelial-to-mesenchymal transition (EndMT) involves the phenotypic conversion of endothelial-to-mesenchymal cells, and was first discovered in association with embryonic heart development. EndMT can regulate various processes, such as tissue fibrosis and cancer. Recent findings have shown that EndMT is related to resistance to cancer therapy, such as chemotherapy, antiangiogenic therapy, and radiation therapy. Based on the known effects of EndMT on the cardiac toxicity of anticancer therapy and tissue damage of radiation therapy, we propose that EndMT can be targeted as a strategy for overcoming tumor resistance while reducing complications, such as tissue damage. In this review, we discuss EndMT and its roles in damaging cardiac and lung tissues, as well as EndMT-related effects on tumor vasculature and resistance in anticancer therapy. Modulating EndMT in radioresistant tumors and radiation-induced tissue fibrosis can especially increase the efficacy of radiation therapy. In addition, we review the role of hypoxia and reactive oxygen species as the main stimulating factors of tissue damage due to vascular damage and EndMT. We consider drugs that may be clinically useful for regulating EndMT in various diseases. Finally, we argue the importance of EndMT as a therapeutic target in anticancer therapy for reducing tissue damage.

A process of cellular conversion known as endothelial-to-mesenchymal transition (EndMT) may offer a valuable target for treating cancer and other diseases. In EndMT, the cells lining blood vessels undergo a striking change in shape and physiology, acquiring features of cells called fibroblasts. Fibroblasts form the body’s connective tissue, but also produce scar tissue that impairs organ function. Researchers led by Yoon-Jin Lee of the Korea Institute of Radiological & Medical Sciences in Seoul, South Korea, have reviewed the impact of this transformation on human disease. EndMT is seen as a prelude to heart failure, in lung tissue affected by pulmonary fibrosis, and within tumors, where the process recruits cells that further stimulate cancer progression. The authors highlight the potential of using drugs that target EndMT to bolster the efficacy and safety of tumor therapy.

Effects of Arsenic on wnt/β-catenin Signaling Pathway: A Systematic Review and Meta-analysis

We aimed to systematically evaluate the regulatory effect of arsenic on wnt/β-catenin signaling pathway and to provide theoretical basis for revealing the mechanism of the relationship between arsenic and cell proliferation. The meta-analysis was carried out using Revman5.2 and Stata13.0 to describe the differences between groups with standard mean difference. We found in normal cells that the levels of wnt3a, β-catenin, glycogen synthase kinase-3β phosphorylated at serine 9 (p-GSK-3β(Ser9)), cyclinD1, proto-oncogene c-myc, and vascular endothelial growth factor (VEGF) in the arsenic intervention group were higher than those in the control group, and the level of glycogen synthase kinase-3β (GSK-3β) was lower than that in the control group (P < 0.05, respectively). Subgroup analysis showed that for a long time period (>24 h), the level of β-catenin in the arsenic intervention group was higher than that in the control group, and the level of GSK-3β of the same long-time period (>24 h) with low-dose (≤5 μM) intervention was lower than those in the control group (P < 0.05, respectively). In cancer cells, the levels of β-catenin, cyclinD1, c-myc, and VEGF in the arsenic intervention group were lower than those in the control group, while the level of GSK-3β in the arsenic intervention group was higher than that in the control group (P < 0.05, respectively). Subgroup analysis showed that the levels of β-catenin, cyclinD1, and c-myc in the high-dose (>5 μM) arsenic intervention group were lower than those in the control group, and the levels of β-catenin and cyclinD1 in the high-dose (>5 μM) arsenic intervention group were lower than those in the low-dose (≤5 μM) arsenic intervention group (P < 0.05, respectively). In addition, the regulation of arsenic on β-catenin was dose-dependent in the range of arsenic concentration from 0 to 7.5 μM. This study revealed that arsenic could upregulate wnt/β-catenin signaling pathway in normal cells and downregulate it in cancer cells, and its effect was affected by time and dose.

Non-ischemic dilated cardiomyopathy and cardiac fibrosis

Cardiac fibrosis is associated with non-ischemic dilated cardiomyopathy, increasing its morbidity and mortality. Cardiac fibroblast is the keystone of fibrogenesis, being activated by numerous cellular and humoral factors. Macrophages, CD4+ and CD8+ T cells, mast cells, and endothelial cells stimulate fibrogenesis directly by activating cardiac fibroblasts and indirectly by synthetizing various profibrotic molecules. The synthesis of type 1 and type 3 collagen, fibronectin, and α-smooth muscle actin is rendered by various mechanisms like transforming growth factor-beta/small mothers against decapentaplegic pathway, renin angiotensin system, and estrogens, which in turn alter the extracellular matrix. Investigating the underlying mechanisms will allow the development of diagnostic and prognostic tools and discover novel specific therapies. Serum biomarkers aid in the diagnosis and tracking of cardiac fibrosis progression. The diagnostic gold standard is cardiac magnetic resonance with gadolinium administration that allows quantification of cardiac fibrosis either by late gadolinium enhancement assessment or by T1 mapping. Therefore, the goal is to stop and even reverse cardiac fibrosis by developing specific therapies that directly target fibrogenesis, in addition to the drugs used to treat heart failure. Cardiac resynchronization therapy had shown to revert myocardial remodeling and to reduce cardiac fibrosis. The purpose of this review is to provide an overview of currently available data.

Tongxinluo Attenuates Myocardiac Fibrosis after Acute Myocardial Infarction in Rats via Inhibition of Endothelial-to-Mesenchymal Transition

Endothelial-to-mesenchymal transition (EndMT) is an essential mechanism in myocardial fibrosis (MF). Tongxinluo (TXL) has been confirmed to protect the endothelium against reperfusion injury after acute myocardial infarction (AMI). However, whether TXL can inhibit MF after AMI via inhibiting EndMT remained unknown. This study aims to identify the role of EndMT in MF after AMI as well as the protective effects and underlying mechanisms of TXL on MF. The AMI model was established in rats by ligating left anterior descending coronary artery. Then, rats were administered with high- (0.8 g·kg⁻¹·d⁻¹), mid- (0.4 g·kg⁻¹·d⁻¹), and low- (0.2 g·kg⁻¹·d⁻¹) dose Tongxinluo and benazepril for 4 weeks, respectively. Cardiac function, infarct size, MF, and related indicators of EndMT were measured. In vitro, human cardiac microvascular endothelial cells (HCMECs) were pretreated with TXL for 4 h and then incubated in hypoxia conditions for 3 days to induce EndMT. Under this hypoxic condition, neuregulin-1 (NRG-1) siRNA were further applied to silence NRG-1 expression. Immunofluorescence microscopy was used to assess expression of endothelial marker of vWF and fibrotic marker of Vimentin. Related factors of EndMT were determined by Western blot analysis. TXL treatment significantly improved cardiac function, ameliorated MF, reduced collagen of fibrosis area (types I and III collagen) and limited excessive extracellular matrix deposition (mmp2 and mmp9). In addition, TXL inhibited EndMT in cardiac tissue and hypoxia-induced HCMECs. In hypoxia-induced HCMECs, TXL increased the expression of endothelial markers, whereas decreasing the expression of fibrotic markers, partially through enhanced expressions of NRG-1, phosphorylation of ErbB2, ErbB4, AKT, and downregulated expressions of hypoxia inducible factor-1a and transcription factor snail. After NRG-1 knockdown, the protective effect of TXL on HCMEC was partially abolished. In conclusion, TXL attenuates MF after AMI by inhibiting EndMT and through activating the NRG-1/ErbB- PI3K/AKT signalling cascade.

Salinomycin triggers endoplasmic reticulum stress through ATP2A3 upregulation in PC-3 cells

Background

Salinomycin is a monocarboxylic polyether antibiotic and is a potential chemotherapy drug. Our previous studies showed that salinomycin inhibited cell growth and targeted CSCs in prostate cancer. However, the precise target of salinomycin action is unclear.

Methods

In this work, we analyzed and identified differentially expressed genes (DEGs) after treatment with or without salinomycin using a gene expression microarray in vitro (PC-3 cells) and in vivo (NOD/SCID mice xenograft model generated from implanted PC-3 cells). Western blotting and immunohistochemical staining were used to analyze the expression of ATP2A3 and endoplasmic reticulum (ER) stress biomarkers. Flow cytometry was used to analyze the cell cycle, apoptosis and intracellular Ca²⁺ concentration.

Results

A significantly upregulated gene, ATPase sarcoplasmatic/endoplasmatic reticulum Ca²⁺ transporting 3 (ATP2A3), was successfully identified. In subsequent studies, we found that ATP2A3 overexpression could trigger ER stress and exert anti-cancer effects in PC-3 and DU145 cells. ATP2A3 was slightly expressed, but the ER stress biomarkers showed strong staining in prostate cancer tissues. We also found that salinomycin could trigger ER stress, which might be related to ATP2A3-mediated Ca²⁺ release in PC-3 cells. Furthermore, we found that salinomycin-triggered ER stress could promote apoptosis and thus exert anti-cancer effects in prostate cancer cells.

Conclusion

This study demonstrates that ATP2A3 might be one of the potential targets for salinomycin, which can inhibit Ca²⁺ release and trigger ER stress to exert anti-cancer effects.

Pharmacological inhibition of β-catenin prevents EndMT in vitro and vascular remodeling in vivo resulting from endothelial Akt1 suppression

Endothelial to mesenchymal transition (EndMT), where endothelial cells acquire mesenchymal characteristics has been implicated in several cardiopulmonary, vascular and fibrotic diseases. The most commonly studied molecular mechanisms involved in EndMT include TGFβ, Notch, interleukin, and interferon-γ signaling. As of today, the contributions of Akt1, an important mediator of TGFβ signaling and a key regulator of endothelial barrier function to EndMT remains unclear. By using the ShRNA based gene silencing approach and endothelial-specific inducible Akt1 knockdown (ECKO^Akt1) mice, we studied the role of Akt1 in EndMT in vitro and pathological vascular remodeling in vivo. Stable, Akt1 silenced (ShAkt1) human microvascular endothelial cells (HMECs) indicated increased expression of mesenchymal markers such as N-cadherin and α-SMA, phosphorylation of Smad2/3, cellular stress via activation of p38 MAP Kinase and the loss of endothelial nitric oxide synthase (eNOS) accompanied by a change in the morphology of HMECs in vitro and co-localization of endothelial and mesenchymal markers promoting EndMT in vivo. EndMT as a result of Akt1 loss was associated with increased expression of TGFβ2, a potent inducer of EndMT and mesenchymal transcription factors Snail1, and FoxC2. We observed that hypoxia-induced lung vascular remodeling is exacerbated in ECKO^Akt1 mice, which was reversed by pharmacological inhibition of β-catenin. Thus, we provide novel insights into the role of Akt1-mediated β-catenin signaling in EndMT and pathological vascular remodeling, and present β-catenin as a potential target for therapy for various cardiopulmonary diseases involving vascular remodeling.

Ganoderma triterpenes Protect Against Hyperhomocysteinemia Induced Endothelial-Mesenchymal Transition via TGF-β Signaling Inhibition

Endothelial dysfunction is one of the most important pathological status in hyperhomocysteinemia (HHcy) related cardiovascular diseases. Whereas, the underlying mechanisms have not been fully elucidated yet, concomitant with the absence of effective treatment. The purpose of this study was to explore the main mechanisms involved in HHcy-induced endothelial injury and identify the protective effect of Ganoderma triterpenes (GT). Bovine aortic endothelial cells (BAECs) were applied as in vitro experimental model. The small molecular inhibitors were used to explore the signalings involved in HHcy-induced endothelial injury. The experimental results provided initial evidence that HHcy led to endothelial-mesenchymal transition (EndMT). Meanwhile, TGF-β/Smad, PI3K/AKT and MAPK pathways were activated in this process, which was demonstrated by pretreatment with TGF-β RI kinase inhibitor VI SB431542, PI3K inhibitor LY294002, p38 inhibitor SB203580, and ERK inhibitor PD98059. Furthermore, it was found that GT restrained the process of HHcy-induced EndMT via reducing oxidative stress and suppressing fore mentioned pathways with further inhibiting the activity of Snail. These results implicate that there is an untapped potential for GT as a novel therapeutic candidate for HHcy-induced EndMT through alleviating oxidative stress and canonical TGF-β/Smad and non-Smad dependent signaling pathways.

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.

Bone morphogenetic protein-7 inhibits endothelial-mesenchymal transition in pulmonary artery endothelial cell under hypoxia

Pulmonary artery hypertension (PAH) is characterized by structural changes in pulmonary arteries. Increased numbers of cells expressing α-smooth muscle actin (α-SMA) is a nearly universal finding in the remodeled artery. It has been confirmed endothelial-to-mesenchymal transition (EndoMT) may be a source of those α-SMA-expressing cells. In addition, the EndoMT is reversible. Here, we show that under hypoxia, the expression of bone morphogenetic protein 7 (BMP-7) was decreased both in vivo and in vitro. We also found that under normoxia, BMP-7 deficiency induced spontaneous EndoMT and cell migration. The hypoxia-induced EndoMT and cell migration were markedly attenuated after pretreatment with rh-BMP-7. Moreover, m-TOR phosphorylation was involved in EndoMT and BMP-7 suppressed hypoxia-induced m-TORC1 phosphorylation in pulmonary artery endothelial cells. Our results demonstrate that BMP-7 attenuates the hypoxia-induced EndoMT and cell migration by suppressing the m-TORC1 signaling pathway. Our study revealed a novel mechanism underlying the hypoxia-induced EndoMT in pulmonary artery endothelial cells and suggested a new therapeutic strategy targeting EndoMT for the treatment of pulmonary arterial hypertension.

Prolyl 4-Hydroxylase Domain Protein 3 Overexpression Improved Obstructive Sleep Apnea-Induced Cardiac Perivascular Fibrosis Partially by Suppressing Endothelial-to-Mesenchymal Transition

BACKGROUND

Intermittent hypoxia (IH) induced by obstructive sleep apnea is the key factor involved in cardiovascular fibrosis. Under persistent hypoxia condition, endothelial cells respond by endothelial-to-mesenchymal transition (EndMT), which is associated with cardiovascular fibrosis. Prolyl 4-hydroxylase domain protein 3 (PHD3) is a cellular oxygen sensor and its expression increased in hypoxia. However, its role in obstructive sleep apnea-induced EndMT and cardiovascular fibrosis is still uncertain. We investigated the potential mechanism of obstructive sleep apnea-induced cardiac perivascular fibrosis and the role of PHD3 in it.

METHODS AND RESULTS

In vivo, C56BL/6 mice were exposed to IH for 12 weeks. PHD3 expression was changed by lentivirus-mediated short-hairpin PHD3 and lentivirus carrying PHD3 cDNA. EndMT related protein levels, histological and functional parameters were detected after 12 weeks. In vitro, human umbilical vein endothelial cells were treated with IH/short-hairpin PHD3/lentivirus carrying PHD3 cDNA to explore the mechanism of PHD3 in altered function of human umbilical vein endothelial cells. We found that chronic intermittent hypoxia increase PHD3 expression and EndMT. In vivo, IH accelerate cardiac dysfunction and aggravate collagen deposition via the process of EndMT. And, when PHD3 were overexpressed, cardiac dysfunction and collagen excessive deposition were improved. In vitro, IH induced EndMT, which endow human umbilical vein endothelial cells spindle morphology and an enhanced ability to migration and collagen secretion. PHD3 overexpression in cultured human umbilical vein endothelial cells ameliorated IH-induced EndMT through inactivating hypoxia-inducible factor 1 alpha and small mothers against decapentaplegic 2 and 3.

CONCLUSIONS

Obstructive sleep apnea-induced cardiac perivascular fibrosis is associated with EndMT, and PHD3 overexpression might be beneficial in the prevention of it by inhibiting EndMT. PHD3 overexpression might have therapeutic potential in the treatment of the disease.

TGF-β-Induced Endothelial-Mesenchymal Transition in Fibrotic Diseases

Fibrotic diseases are characterized by net accumulation of extracellular matrix proteins in affected organs leading to their dysfunction and ultimate failure. Myofibroblasts have been identified as the cells responsible for the progression of the fibrotic process, and they originate from several sources, including quiescent tissue fibroblasts, circulating CD34⁺ fibrocytes and the phenotypic conversion of various cell types into activated myofibroblasts. Several studies have demonstrated that endothelial cells can transdifferentiate into mesenchymal cells through a process termed endothelial- mesenchymal transition (EndMT) and that this can give rise to activated myofibroblasts involved in the development of fibrotic diseases. Transforming growth factor β (TGF-β) has a central role in fibrogenesis by modulating the fibroblast phenotype and function, inducing myofibroblast transdifferentiation and promoting matrix accumulation. In addition, TGF-β by inducing EndMT may further contribute to the development of fibrosis. Despite extensive investigation of the pathogenesis of fibrotic diseases, no effective treatment strategies are available. Delineation of the mechanisms responsible for initiation and progression of fibrotic diseases is crucial for the development of therapeutic strategies for the treatment of the disease. In this review, we summarize the role of the TGF-β signaling pathway and EndMT in the development of fibrotic diseases and discuss their therapeutic potential.

Comparative proteomic analysis reveals heart toxicity induced by chronic arsenic exposure in rats

Arsenic is a widespread metalloid in the environment, which poses a broad spectrum of adverse effects on human health. However, a global view of arsenic-induced heart toxicity is still lacking, and the underlying molecular mechanisms remain unclear. By performing a comparative quantitative proteomic analysis, the present study aims to investigate the alterations of proteome profile in rat heart after long-term exposure to arsenic. As a result, we found that the abundance of 81 proteins were significantly altered by arsenic treatment (35 up-regulated and 46 down-regulated). Among these, 33 proteins were specifically associated with cardiovascular system development and function, including heart development, heart morphology, cardiac contraction and dilation, and other cardiovascular functions. It is further proposed that the aberrant regulation of 14 proteins induced by arsenic would disturb cardiac contraction and relaxation, impair heart morphogenesis and development, and induce thrombosis in rats, which is mediated by the Akt/p38 MAPK signaling pathway. Overall, these findings will augment our knowledge of the involved mechanisms and develop useful biomarkers for cardiotoxicity induced by environmental arsenic exposure.

Proteomics/phosphoproteomics of left ventricular biopsies from patients with surgical coronary revascularization and pigs with coronary occlusion/reperfusion: remote ischemic preconditioning

Remote ischemic preconditioning (RIPC) by repeated brief cycles of limb ischemia/reperfusion reduces myocardial ischemia/reperfusion injury. In left ventricular (LV) biopsies from patients undergoing coronary artery bypass grafting (CABG), only the activation of signal transducer and activator of transcription 5 was associated with RIPC’s cardioprotection. We have now used an unbiased, non-hypothesis-driven proteomics and phosphoproteomics approach to analyze LV biopsies from patients undergoing CABG and from pigs undergoing coronary occlusion/reperfusion without (sham) and with RIPC. False discovery rate-based statistics identified a higher prostaglandin reductase 2 expression at early reperfusion with RIPC than with sham in patients. In pigs, the phosphorylation of 116 proteins was different between baseline and early reperfusion with RIPC and/or with sham. The identified proteins were not identical for patients and pigs, but in-silico pathway analysis of proteins with ≥2-fold higher expression/phosphorylation at early reperfusion with RIPC in comparison to sham revealed a relation to mitochondria and cytoskeleton in both species. Apart from limitations of the proteomics analysis per se, the small cohorts, the sampling/sample processing and the number of uncharacterized/unverifiable porcine proteins may have contributed to this largely unsatisfactory result.

Lovastatin Alleviates Endothelial-to-Mesenchymal Transition in Glomeruli via Suppression of Oxidative Stress and TGF-β1 Signaling

Statins may decrease chronic kidney diseases (CKDs) risk, but their underlying molecular mechanisms are not completely understood. Recent studies indicate Endothelial-to-mesenchymal transition (EndMT) plays an important role contributing to renal interstitial fibrosis. In the present study, we first investigated whether lovastatin could ameliorate renal fibrosis via suppression of EndMT and its possible mechanism. In vitro experiments, lovastatin significantly ameliorated microalbuminuria and pathologic changes in diabetic rats. Double labeling immunofluorescence showed lovastatin could inhibit EndMT in glomeruli. Furthermore, lovastatin could inhibit oxidative stress and down-regulate TGF-β1-Smad signaling. Consistent alterations were observed in vivo that lovastatin substantially suppressed EndMT and TGF-β1 signaling induced by high glucose in glomerular endothelial cells (GEnCs). These data indicated that lovastatin could ameliorate EndMT in glomeruli in diabetic nephropathy, the mechanism of which might be at least partly through suppression of oxidative stress and TGF-β1/Smad signaling pathway.

Salinomycin Exerts Anticancer Effects on PC-3 Cells and PC-3-Derived Cancer Stem Cells In Vitro and In Vivo

Salinomycin is an antibiotic isolated from Streptomyces albus that selectively kills cancer stem cells (CSCs). However, the antitumor mechanism of salinomycin is unclear. This study investigated the chemotherapeutic efficacy of salinomycin in human prostate cancer PC-3 cells. We found that cytotoxicity of salinomycin to PC-3 cells was stronger than to nonmalignant prostate cell RWPE-1, and exposure to salinomycin induced G2/M phage arrest and apoptosis of PC-3 cells. A mechanistic study found salinomycin suppressed Wnt/β-catenin pathway to induce apoptosis of PC-3 cells. An in vivo experiment confirmed that salinomycin suppressed tumorigenesis in a NOD/SCID mice xenograft model generated from implanted PC-3 cells by inhibiting the Wnt/β-catenin pathway, since the total β-catenin protein level was reduced and the downstream target c-Myc level was significantly downregulated. We also showed that salinomycin, but not paclitaxel, triggered more apoptosis in aldehyde dehydrogenase- (ALDH-) positive PC-3 cells, which were considered as the prostate cancer stem cells, suggesting that salinomycin may be a promising chemotherapeutic to target CSCs. In conclusion, this study suggests that salinomycin reduces resistance and relapse of prostate tumor by killing cancer cells as well as CSCs.

Endothelial-to-mesenchymal transition: A novel therapeutic target for cardiovascular diseases

Endothelial-to-mesenchymal transition (EndMT) is a complex biological process in which endothelial cells lose their specific markers and acquire a mesenchymal or myofibroblastic phenotype. Similar to epithelial-to-mesenchymal transition (EMT), EndMT can be induced by multiple stimulants such as cytokines and metabolic factors that play crucial roles in the development of the cardiovascular system. Recent studies have demonstrated that EndMT may play a significant role in the pathogenesis of cardiovascular diseases (CVDs), and may represent a novel therapeutic target for cardiovascular remodeling and fibrotic disorders. The exact molecular mechanisms involved in cardiovascular pathogenesis that occur as a result of EndMT, however, are not fully explained. In this review, we reveal the multiple intercellular mechanisms of EndMT including stimulants, signaling pathways, and seek to explore the relationship between this biological process, cardiovascular system development, and CVDs that may lead to new therapeutic strategies for the treatment of CVDs.