Signaling by ALK5 mediates TGF-β-induced ET-1 expression in endothelial cells: a role for migration and proliferation

ALK5/VEGFR2 dual inhibitor TU2218 alone or in combination with immune checkpoint inhibitors enhances immune-mediated antitumor effects

Transforming growth factor β (TGFβ) is present in blood of patients who do not respond to anti-programmed cell death (ligand) 1 [PD-(L)1] treatment, and through synergy with vascular endothelial growth factor (VEGF), it helps to create an environment that promotes tumor immune evasion and immune tolerance. Therefore, simultaneous inhibition of TGFβ/VEGF is more effective than targeting TGFβ alone. In this study, the dual inhibitory mechanism of TU2218 was identified through in vitro analysis mimicking the tumor microenvironment, and its antitumor effects were analyzed using mouse syngeneic tumor models. TU2218 directly restored the activity of damaged cytotoxic T lymphocytes (CTLs) and natural killer cells inhibited by TGFβ and suppressed the activity and viability of regulatory T cells. The inactivation of endothelial cells induced by VEGF stimulation was completely ameliorated by TU2218, an effect not observed with vactosertib, which inhibits only TGFβ signaling. The combination of TU2218 and anti-PD1 therapy had a significantly greater antitumor effect than either drug alone in the poorly immunogenic B16F10 syngeneic tumor model. The mechanism of tumor reduction was confirmed by flow cytometry, which showed upregulated VCAM-1 expression in vascular cells and increased influx of CD8 + CTLs into the tumor. As another strategy, combination of anti-CTLA4 therapy and TU2218 resulted in high complete regression (CR) rates in CT26 and WEHI-164 tumor models. In particular, immunological memory generated by the combination of anti-CTLA4 and TU2218 in the CT26 model prevented the development of tumors after additional tumor cell transplantation, suggesting that the TU2218-based combination has therapeutic potential in immunotherapy.

Tanshinone IIA: a Chinese herbal ingredient for the treatment of atherosclerosis

Tanshinone IIA (Tan IIA) is a fat-soluble compound extracted from Salvia miltiorrhiza, which has a protective effect against atherosclerosis (AS). Tan IIA can inhibit oxidative stress and inflammatory damage of vascular endothelial cells (VECs) and improve endothelial cell dysfunction. Tan IIA also has a good protective effect on vascular smooth muscle cells (VSMCs). It can reduce vascular stenosis by inhibiting the proliferation and migration of vascular smooth muscle cells (VSMCs), and improve the stability of the fibrous cap of atherosclerotic plaque by inhibiting apoptosis and inflammation of VSMCs. In addition, Tan IIA inhibits the inflammatory response of macrophages and the formation of foam cells in atherosclerotic plaques. In summary, Tan IIA improves AS through a complex pathway. We propose to further study the specific molecular targets of Tan IIA using systems biology methods, so as to fundamentally elucidate the mechanism of Tan IIA. It is worth mentioning that there is a lack of high-quality evidence-based medical data on Tan IIA treatment of AS. We recommend that a randomized controlled clinical trial be conducted to evaluate the exact efficacy of Tan IIA in improving AS. Finally, sodium tanshinone IIA sulfonate (STS) can cause adverse drug reactions in some patients, which needs our attention.

The Role of Polymorphism in the Endothelial Homeostasis and Vitamin D Metabolism Genes in the Severity of Coronary Artery Disease

Coronary artery disease (CAD) remains one of the leading causes of cardiovascular morbidity and mortality worldwide. The maintenance of endothelial homeostasis and vitamin D metabolism play an important role in CAD pathogenesis. This study aimed to determine the association of endothelial homeostasis and vitamin D metabolism gene polymorphism with CAD severity. A total of 224 low-risk patients (SYNTAX score ≤ 31) and 36 high-risk patients (SYNTAX score > 31) were recruited for this study. The serum level of E-, L- and P-selectins; endothelin; eNOS; 25OH; and 1.25-dihydroxy vitamin D was measured using an enzyme-linked immunosorbent assay (ELISA). Polymorphic variants in SELE, SELP, SELPLG, END1, NOS3, VDR and GC were analyzed using a polymerase chain reaction (PCR). We found no differences in the serum levels of the studied markers between high- and low-risk patients. Three polymorphic variants associated with CAD severity were discovered: END1 rs3087459, END1 rs5370 and GC rs2298849 in the log-additive model. Moreover, we discovered a significantly decreased serum level of 1.25-dihydroxy vitamin D in high-risk CAD patients with the A/A-A/G genotypes of the rs2228570 polymorphism of the VDR gene, the A/A genotype of the rs7041 polymorphism of the GC gene and the A/A genotype of the rs2298849 polymorphism of the GC gene.

Smad3 promotes adverse cardiovascular remodeling and dysfunction in doxorubicin-treated hearts

Many anticancer therapies cause serious cardiovascular complications that degrade quality of life and cause early mortality in treated patients. Specifically, doxorubicin is known as an effective anticancer agent that causes cardiomyopathy in treated patients. There has been growing interest in defining the role of endothelial cells in cardiac damage by doxorubicin. We have shown in the present study that endothelial nuclei accumulate more intravenously administered doxorubicin than other cardiac cell types. Doxorubicin enhanced cardiac production of the transforming growth factor-β (TGF-β) ligands and nuclear translocation of phospho-Smad3 in both cultured and in vivo cardiac endothelial cells. To examine the role of the TGF-β/mothers against decapentaplegic homolog 3 (Smad3) pathway in cardiac damage by doxorubicin, we used both Smad3 shRNA stable endothelial cell lines and Smad3-knockout mice. We demonstrated using endothelial transcriptome analysis that upregulation of the TGF-β and inflammatory cytokine/cytokine receptor pathways, as well as suppression of cell cycle and angiogenesis by doxorubicin, were alleviated in Smad3-deficient endothelial cells. The results of transcriptomic analysis were validated using qPCR, immunoblotting, and ex vivo aortic ring sprouting assays. Similarly, increased cardiac expression of cytokines and chemokines observed in treated wild-type mice was diminished in treated Smad3-knockout animals. We also detected increased end-diastolic diameter and depressed systolic function in doxorubicin-treated wild-type but not Smad3-knockout mice. This work provides evidence for the critical role of the canonical TGF-β/Smad3 pathway in cardiac damage by doxorubicin.NEW & NOTEWORTHY Microvascular endothelial cells in the heart accumulate more intravenously administered doxorubicin than nonendothelial cardiac cell types. The treatment enhanced the TGF-β/Smad3 pathway and elicited endothelial cell senescence and inflammatory responses followed by adverse cardiac remodeling and dysfunction in wild-type but not Smad3-deficient animals. Our study suggests that the TGF-β/Smad3 pathway contributes to the development of doxorubicin cardiomyopathy and the potential value of novel approaches to ameliorate cardiotoxicity by targeting the Smad3 transcription factor.

Deciphering the myth of icariin and synthetic derivatives in improving erectile function from a molecular biology perspective: a narrative review

Background and Objective

Although epimedium herb (EH) has been widely used in ancient Chinese medicine to enhance sexual activity, its pharmacological mechanism is not clear. Modern studies have shown that epimedium herb is rich in icariin (ICA, a flavonoid compound), and 91.2% of icariin is converted to icariside II (ICA II) by hydrolytic enzymes in intestinal bacteria after oral administration. YS-10 is a synthetic derivative of icariside II. The aim of this review was to summarize the contemporary evidence regarding the pharmacokinetics, therapeutic properties, and molecular biological mechanisms of ICA and some ICA derivatives for erectile dysfunction therapy.

Methods

A detailed search was conducted in the PubMed database using keywords and phrases, such as “icariin” AND “erectile dysfunction”, “icariside II” AND “erectile dysfunction”. The publication time is limited to last 20 years. Articles had to be published in peer reviewed journals.

Key Content and Findings

ICA and its some derivatives showed the specific inhibition on phosphodiesterase type 5 (PDE5) and the promotion of testosterone synthesis. In addition, by regulating various reliable evidence of signaling pathways such as PI3K/AKT, TGFβ1/Smad2, p38/MAPK, Wnt and secretion of various cytokines, ICA and ICA derivatives can activate endogenous stem cells (ESCs) leading to endothelial cell and smooth muscle cell proliferation, nerve regeneration and fibrosis inhibition, repair pathological changes in penile tissue and improve erectile function.

Conclusions

ICA and some of its derivatives could be a potential treatment for restoring spontaneous erections. In addition ICA and his derivatives may also be valuable as a regenerative medicine approach for other diseases, but more clinical and basic researches with high quality and large samples are recommended.

The role of endothelin and RAS/ERK signaling in immunopathogenesis-related fibrosis in patients with systemic sclerosis: an updated review with therapeutic implications

Systemic sclerosis (SSc) is a disease of connective tissue with high rate of morbidity and mortality highlighted by extreme fibrosis affecting various organs such as the dermis, lungs, and heart. Until now, there is no specific cure for the fibrosis occurred in SSc disease. The SSc pathogenesis is yet unknown, but transforming growth factor beta (TGF-β), endothelin-1 (ET-1), and Ras-ERK1/2 cascade are the main factors contributing to the tissue fibrosis through extracellular matrix (ECM) accumulation. Several studies have hallmarked the association of ET-1 with or without TGF-β and Ras-ERK1/2 signaling in the development of SSc disease, vasculopathy, and fibrosis of the dermis, lungs, and several organs. Accordingly, different clinical and experimental studies have indicated the potential therapeutic role of ET-1 and Ras antagonists in these situations in SSc. In addition, ET-1 and connective tissue growth factor (CTGF) as a cofactor of the TGF-β cascade play a substantial initiative role in inducing fibrosis. Once initiated, TGF-β alone or in combination with ET-1 and CTGF can activate several kinase proteins such as the Ras-ERK1/2 pathway that serve as the fundamental factor for developing fibrosis. Furthermore, Salirasib is a synthetic small molecule that is able to inhibit all Ras forms. Therefore, it can be used as a potent therapeutic factor for fibrotic disorders. So, this review discusses the role of TGF-β/ET-1/Ras signaling and their involvement in SSc pathogenesis, particularly in its fibrotic situation.

Endothelial cell-derived fibroblast growth factor-18 regulates ovarian function in sheep

Increasing the efficiency of farm animal reproduction is necessary to reduce the environmental impact of food production systems. One approach is to increase the number of healthy eggs (oocytes) produced per female for fertilization, thus it is important to understand factors that decrease oocyte health. One paracrine factor that decreases ovarian follicle growth is fibroblast growth factor 18 (FGF18) secreted by cells in the theca layer of the ovarian follicle, however the factors that regulate FGF18 secretion are unknown. In this study we hypothesized that FGF18 secretion is controled by intrafollicular factors and is linked to fertility, which we tested by using cell culture and sheep genetic models in vivo. Separation of theca cell populations revealed that FGF18 messenger RNA (mRNA) is located mainly in thecal endothelial rather than endocrine cells, and immunohistochemistry localized FGF18 protein to microvessels in the theca layer in situ. Culture of ovine theca-derived endothelial cells was used to demonstrate stimulation of FGF18 mRNA and protein abundance by bone morphogenetic protein 4 (BMP4), a growth factor derived from theca endocrine cells. Taking advantage of a sheep genetic model, we demonstrate reduced ovarian and peripheral FGF18 concentrations in the hyperprolific Booroola ewe harboring the FecB^B mutation in BMPR1B. These data suggest a novel control of fertility by follicular endothelial cells, in which theca endocrine cells secrete BMP4 that stimulates the secretion of FGF18 from thecal endothelial cells, which in turn diffuses into the granulosa cell layer and promotes apoptosis.

Therapeutic Approaches for Treating Pulmonary Arterial Hypertension by Correcting Imbalanced TGF-β Superfamily Signaling

Pulmonary arterial hypertension (PAH) is a rare disease characterized by high blood pressure in the pulmonary circulation driven by pathological remodeling of distal pulmonary arteries, leading typically to death by right ventricular failure. Available treatments improve physical activity and slow disease progression, but they act primarily as vasodilators and have limited effects on the biological cause of the disease—the uncontrolled proliferation of vascular endothelial and smooth muscle cells. Imbalanced signaling by the transforming growth factor-β (TGF-β) superfamily contributes extensively to dysregulated vascular cell proliferation in PAH, with overactive pro-proliferative SMAD2/3 signaling occurring alongside deficient anti-proliferative SMAD1/5/8 signaling. We review the TGF-β superfamily mechanisms underlying PAH pathogenesis, superfamily interactions with inflammation and mechanobiological forces, and therapeutic strategies under development that aim to restore SMAD signaling balance in the diseased pulmonary arterial vessels. These strategies could potentially reverse pulmonary arterial remodeling in PAH by targeting causative mechanisms and therefore hold significant promise for the PAH patient population.

Promising Biomarkers of Radiation-Induced Lung Injury: A Review

Radiation-induced lung injury (RILI) is one of the main dose-limiting side effects in patients with thoracic cancer during radiotherapy. No reliable predictors or accurate risk models are currently available in clinical practice. Severe radiation pneumonitis (RP) or pulmonary fibrosis (PF) will reduce the quality of life, even when the anti-tumor treatment is effective for patients. Thus, precise prediction and early diagnosis of lung toxicity are critical to overcome this longstanding problem. This review summarizes the primary mechanisms and preclinical animal models of RILI reported in recent decades, and analyzes the most promising biomarkers for the early detection of lung complications. In general, ideal integrated models considering individual genetic susceptibility, clinical background parameters, and biological variations are encouraged to be built up, and more prospective investigations are still required to disclose the molecular mechanisms of RILI as well as to discover valuable intervention strategies.

Tanshinone IIA protects mice against atherosclerotic injury by activating the TGF-β/PI3K/Akt/eNOS pathway

Explored the mechanism of action of tanshinone IIA (TIIA) against atherosclerosis.

A GSK3-SRF Axis Mediates Angiotensin II Induced Endothelin Transcription in Vascular Endothelial Cells

Endothelin, encoded by ET1, is a vasoactive substance primarily synthesized in vascular endothelial cells (VECs). Elevation of endothelin levels, due to transcriptional hyperactivation, has been observed in a host of cardiovascular diseases. We have previously shown that serum response factor (SRF) is a regulator of ET1 transcription in VECs. Here we report that angiotensin II (Ang II) induced ET1 transcription paralleled activation of glycogen synthase kinase 3 (GSK3) in cultured VECs. GSK3 knockdown or pharmaceutical inhibition attenuated Ang II induced endothelin expression. Of interest, the effect of GSK3 on endothelin transcription relied on the conserved SRF motif within the ET1 promoter. Further analysis revealed that GSK3 interacted with and phosphorylated SRF at serine 224. Phosphorylation of SRF by GSK3 did not influence its recruitment to the ET1 promoter. Instead, GSK3-mediated SRF phosphorylation potentiated its interaction with MRTF-A, a key co-factor for SRF, which helped recruit the chromatin remodeling protein BRG1 to the ET1 promoter resulting in augmented histone H3 acetylation/H3K4 trimethylation. Consistently, over-expression of a constitutively active GSK enhanced Ang II-induced ET1 transcription and knockdown of either MRTF-A or BRG1 abrogated the enhancement of ET1 transcription. In conclusion, our data highlight a previously unrecognized mechanism that contributes to the transcriptional regulation of endothelin. Targeting this GSK3-SRF axis may yield novel approaches in the intervention of cardiovascular diseases.

The Genomic Response to TGF-β1 Dictates Failed Repair and Progression of Fibrotic Disease in the Obstructed Kidney

Tubulointerstitial fibrosis is a common and diagnostic hallmark of a spectrum of chronic renal disorders. While the etiology varies as to the causative nature of the underlying pathology, persistent TGF-β1 signaling drives the relentless progression of renal fibrotic disease. TGF-β1 orchestrates the multifaceted program of kidney fibrogenesis involving proximal tubular dysfunction, failed epithelial recovery or re-differentiation, capillary collapse and subsequent interstitial fibrosis eventually leading to chronic and ultimately end-stage disease. An increasing complement of non-canonical elements function as co-factors in TGF-β1 signaling. p53 is a particularly prominent transcriptional co-regulator of several TGF-β1 fibrotic-response genes by complexing with TGF-β1 receptor-activated SMADs. This cooperative p53/TGF-β1 genomic cluster includes genes involved in cellular proliferative control, survival, apoptosis, senescence, and ECM remodeling. While the molecular basis for this co-dependency remains to be determined, a subset of TGF-β1-regulated genes possess both p53- and SMAD-binding motifs. Increases in p53 expression and phosphorylation, moreover, are evident in various forms of renal injury as well as kidney allograft rejection. Targeted reduction of p53 levels by pharmacologic and genetic approaches attenuates expression of the involved genes and mitigates the fibrotic response confirming a key role for p53 in renal disorders. This review focuses on mechanisms underlying TGF-β1-induced renal fibrosis largely in the context of ureteral obstruction, which mimics the pathophysiology of pediatric unilateral ureteropelvic junction obstruction, and the role of p53 as a transcriptional regulator within the TGF-β1 repertoire of fibrosis-promoting genes.

Dihydroartemisinin inhibits endothelial cell migration via the TGF-β1/ALK5/SMAD2 signaling pathway

Anti-angiogenesis therapy is a novel treatment method for malignant tumors. Endothelial cell (EC) migration is an important part of angiogenesis. Dihydroartemisinin (DHA) exhibits strong anti-angiogenic and anti-EC migration effects; however, the underlying molecular mechanisms are yet to be elucidated. The TGF-β1/activin receptor-like kinase 5 (ALK5)/SMAD2 signaling pathway serves an important role in the regulation of migration. The present study aimed to explore the effects of DHA treatment on EC migration and the TGF-β1/ALK5/SMAD2 signaling pathway. The effects of DHA on human umbilical vein EC migration were assessed using wound healing and Transwell assays. The effects of DHA on the TGF-β1/ALK5/SMAD2 signaling pathway were detected using western blotting. DHA exhibited an inhibitory effect on EC migration in the wound healing and Transwell assays. DHA treatment upregulated the expression levels of ALK5 and increased the phosphorylation of SMAD2 in ECs. SB431542 rescued the inhibitory effect of DHA during EC migration. DHA inhibited EC migration via the TGF-β1/ALK5/SMAD2-dependent signaling pathway, and DHA may be a novel drug for the treatment of patients with malignant tumors.

Endothelin antagonism and sodium glucose Co-transporter 2 inhibition. A potential combination therapeutic strategy for COVID-19

The novel coronavirus 2019 (COVID-19) infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a global pandemic that requires a multi-faceted approach to tackle this unprecedent health crisis. Therapeutics to treat COVID-19 are an integral part of any such management strategy and there is a substantial unmet need for treatments for individuals most at risk of severe disease. This perspective review provides rationale of a combined therapeutic regimen of selective endothelin-A (ET-A) receptor antagonism and sodium glucose co-transporter-2 (SGLT-2) inhibition to treat COVID-19. Endothelin is a potent vasoconstrictor with pro-inflammatory and atherosclerotic effects. It is upregulated in a number of conditions including acute respiratory distress syndrome and cardiovascular disease. Endothelin mediates vasocontractility via endothelin (ET-A and ET-B) receptors on vascular smooth muscle cells (VSMCs). ET-B receptors regulate endothelin clearance and are present on endothelial cells, where in contrast to their role on VSMCs, mediate vasodilation. Therefore, selective endothelin-A (ET-A) receptor inhibition is likely the optimal approach to attenuate the injurious effects of endothelin and may reduce ventilation-perfusion mismatch and pulmonary inflammation, whilst improving pulmonary haemodynamics and oxygenation. SGLT-2 inhibition may dampen inflammatory cytokines, reduce hyperglycaemia if present, improve endothelial function, cardiovascular haemodynamics and cellular bioenergetics. This combination therapeutic approach may therefore have beneficial effects to mitigate both the pulmonary, metabolic and cardiorenal manifestations of COVID-19. Given these drug classes include medicines licensed to treat heart failure, diabetes and pulmonary hypertension respectively, information regarding their safety profile is established. Randomised controlled clinical trials are the best way to determine efficacy and safety of these medicines in COVID-19.

ROLE OF THE TRANSFORMING GROWTH FACTOR β1 IN THE GENESIS OF ARTERIAL HYPERTENSION AND ITS COMPLICATIONS

Transforming growth factor beta 1 (TGFβ1) is an actively studied cytokine with rather contradictory effects. The article systematizes and summarizes the scientific data on TGFβ1 and its role in the development and progression of arterial hypertension, with an emphasis on arterial stiffness.

The role of endothelin-1 and its autoantibodies in the pathogenesisof atopic dermatitis: a case-control study

Background. Atopic dermatitis is a chronic multifactorial dermatosis with a complex pathophysiological basis. One of the poorly studied links in the pathogenesis of the disease is endothelin-1. Its main biological effects include pronounced vasoconstriction of blood vessels. Aim. To study the role of endothelin-1 and its autoantibodies in the pathogenesis of atopic dermatitis. Materials and methods. The study included 40 patients with common and limited forms of atopic dermatitis in the period of exacerbation and remission. The concentration of endothelin-1 and autoantibodies to it in the blood serum was determined by the ELISA method. Statistical processing of the obtained data was performed using Statistica 6.0. Statistical significance was determined at p 0.05. Results. High concentrations of endothelin-1 and autoantibodies to it were determined during the exacerbation of the disease. When the clinical picture was resolved; the concentration of endothelin-1 and autoantibodies to it significantly decreased; but remained higher than the control group. Based on the data obtained; it can be assumed that an increase in the concentration of endothelin-1 may be a marker of white dermographism and a regulator of the microcirculation process in the skin. Conclusions. A high level of endothelin-1 contributes to the development of inflammatory reactions in the skin; white dermographism and itching. Endothelin-1 receptors may be potential aim for targeted therapy of atopic dermatitis.

ALK5 deficiency inhibits macrophage inflammation and lipid loading by targeting KLF4

The transforming growth factor type-β (TGF-β) has been demonstrated to play an important role in the development of atherosclerosis through binding to the serine/threonine kinase transmembrane type I and type II receptors. However, as a key type I receptor for TGF-β, the exact role and the underlying mechanism of Activin receptor-like kinase 5 (ALK5) on macrophage activation involved in atherogenesis remain unclear. In the present study, enhanced ALK5 expression was found in bone marrow derived macrophages (BMDMs) upon OX-LDL stimulation tested by RT-PCR and Western blot, which was further verified by co-immunofluorescence staining. Next, the loss-of-function of ALK5 used AdshALK5 transfection was performed to test the effect of ALK5 on macrophage activation. We observed that ALK5 silencing inhibited pro-inflammatory but promoted anti-inflammatory macrophage markers expression. Moreover, decreased foam cell formation was found in ALK5 knockdown macrophages accompanied by increased cholesterol efflux. Mechanistically, ALK5 knockdown significantly increased KLF4 expression that was responsible for the attenuated macrophage activation induced by ALK5 knockdown. Collectively, these findings suggested that neutralization of ALK5 may act as a promising strategy for the management of atherosclerosis.

Growth factor signaling pathways in vascular development and disease

Angiogenic blood vessel growth is essential to ensure organs receive adequate blood supply to support normal organ function and homeostasis. Angiogenesis involves a complex series of cellular events through which new vessels grow out from existing vasculature. Growth factor signaling, layered over a range of other signaling inputs, orchestrates this process. The response of endothelial cells (ECs) to growth factor signals must be carefully controlled through feedback mechanisms to prevent excessive vessel growth, remodeling or destabilization. In this article, we summarize recent findings describing how ECs respond to growth factor signals during blood vessel development and homeostasis and how perturbation of these responses can lead to disease.

Absence of transforming growth factor beta 1 in murine platelets reduces neointima formation without affecting arterial thrombosis

Platelet degranulation at the site of vascular injury prevents bleeding and may affect the chronic vascular wound healing response. Transforming Growth Factor (TGF)-β1 is a major component of platelet α-granules known to accumulating in thrombi. It was our aim to determine the role of TGFβ1 released from activated platelets for neointima formation following arterial injury and thrombosis. Mice with platelet-specific deletion of TGFβ1 (Plt.TGFβ-KO) underwent carotid artery injury. Immunoassays confirmed the absence of active TGFβ1 in platelet releasates and plasma of Plt.TGFβ-KO mice. Whole blood analyses revealed similar haematological parameters, and tail cut assays excluded major bleeding defects. Platelet aggregation and the acute thrombotic response to injury in vivo did not differ between Plt.TGFβ-KO and Plt.TGFβ-WT mice. Morphometric analysis revealed that absence of TGFβ1 in platelets resulted in a significant reduction of neointima formation with lower neointima area, intima-to-media ratio, and lumen stenosis. On the other hand, the media area was enlarged in mice lacking TGFβ1 in platelets and contained increased amounts of proteases involved in latent TGFβ activation, including MMP2, MMP9 and thrombin. Significantly increased numbers of proliferating cells and cells expressing the mesenchymal markers platelet-derived growth factor receptor-β or fibroblast-specific protein-1, and the macrophage antigen F4/80, were observed in the media of Plt.TGFβ-KO mice, whereas the medial smooth muscle-actin-immunopositive area and collagen content did not differ between genotypes. Our findings support an essential role for platelet-derived TGFβ1 for the vascular remodelling response to arterial injury, apparently independent from the role of platelets in thrombosis or haemostasis.

Mesenchymal stem cells attenuate doxorubicin‑induced cellular senescence through the VEGF/Notch/TGF‑β signaling pathway in H9c2 cardiomyocytes

The clinical use of doxorubicin (Dox) is limited by its cardiotoxicity. The fundamental changes it induces include interstitial myocardial fibrosis and the appearance of senescent cardiomyocytes. Mesenchymal stem cell (MSC)‑based therapies have also been reported to modulate cellular senescence, and have been used effectively to treat age‑related cardiovascular diseases. In the present study, the Transwell system was used to coculture H9c2 cells with MSCs, and their proliferation and viability were assessed. The expression of senescence‑related genes p53 and p16, and telomere length were measured using reverse transcription‑quantitative polymerase chain reaction analysis, and the Jagged‑1/Notch‑1 signaling pathway was detected using western blot analysis. The results revealed that Dox induced the senescence of H9c2 cells, characterized by a low proliferation rate, poor viability, reduced telomere length and impaired telomerase activity, and by marked increases in the expression of p53 and p16. By contrast, when cocultured with MSCs in the presence of Dox, H9c2 cell proliferation and viability increased, whereas the expression levels of p53 and p16 decreased, and telomere length and telomerase activity increased. The mechanism underlying the antisenescence function of MSCs was clarified, which involved the vascular endothelial growth factor (VEGF)/Jagged‑1/Notch‑1/transforming growth factor‑β1 (TGF‑β1) signaling pathway. It was confirmed that inhibiting VEGF, or silencing Jagged‑1 or Notch‑1 with small interfering RNA, or using recombinant TGF‑β1 eliminated the antisenescence effects of MSCs on the Dox‑treated H9c2 cells. The results revealed that MSCs rescued H9c2 cells from Dox‑induced senescence through the release of VEGF, which activated the Jagged‑1/Notch‑1 signaling pathway, leading to the inhibition of TGF‑β1 release. Therefore, treatment with MSCs may have important therapeutic implications on the attenuation of cardiotoxicity in patients with cancer treated with Dox.

The Activation of Human Dermal Microvascular Cells by Poly(I:C), Lipopolysaccharide, Imiquimod, and ODN2395 Is Mediated by the Fli1/FOXO3A Pathway

Endothelial cell (EC) dysfunction has been associated with inflammatory and autoimmune diseases; however, the factors contributing to this dysfunction have not been fully explored. Because activation of TLRs has been implicated in autoimmune diseases, the goal of this study was to determine the effects of TLR ligands on EC function. Human dermal microvascular ECs (HDMECs) treated with TLR3 [Poly(I:C)], TLR4 (LPS), and TLR7 (imiquimod) agonists showed decreased proliferation and a reduced total number of branching tubules in three-dimensional human dermal organoid ex vivo culture. In contrast, the TLR9 ligand class C, ODN2395, increased angiogenesis. The antiproliferative effects of TLR3, TLR4, and TLR7 ligands correlated with significant downregulation of a key regulator of vascular homeostasis, Fli1, whereas TLR9 increased Fli1 levels. Furthermore, Poly(I:C) and LPS induced endothelial to mesenchymal transition that was reversed by the pretreatment with TGF-β neutralizing Ab or re-expression of Fli1. We showed that Fli1 was required for the HDMEC proliferation by transcriptionally repressing FOXO3A. In contrast to TLR9, which suppressed activation of the FOXO3A pathway, TLR3, TLR4, and TLR7 ligands activated FOXO3A as indicated by decreased phosphorylation and increased nuclear accumulation. The inverse correlation between Fli1 and FOXO3A was also observed in the vasculature of scleroderma patients. This work revealed opposing effects of TLR9 and TLR3, TLR4, and TLR7 on the key angiogenic pathways, Fli1 and FOXO3A. Our results provide a mechanistic insight into the regulation of angiogenesis by TLRs and confirm a central role of Fli1 in regulating vascular homeostasis.

The Cellular and Molecular Mechanism of Radiation-Induced Lung Injury

The lung is one of several moderately radiosensitive organs. Radiation-induced lung injury (RILI), including acute radiation pneumonitis and chronic radiation-induced pulmonary fibrosis, occurs most often in radiotherapy of lung cancer, esophageal cancer, and other thoracic cancers. Clinical symptoms of RILI include dry cough, shortness of breath, chest pain, fever, and even severe respiratory failure and death. The occurrence of RILI is a complex process that includes a variety of cellular and molecular interactions which ultimately leads to large fibroblast accumulation, proliferation, and differentiation, resulting in excessive extracellular matrix deposits, causing pulmonary fibrosis. The progress that has been made in recent years in the understanding of cellular and molecular mechanisms of RILI is summarized in this review.

Pulmonary hypertension due to left heart disease causes intrapulmonary venous arterialization in rats

OBJECTIVE

A rat model of left atrial stenosis-associated pulmonary hypertension due to left heart diseases was prepared to elucidate its mechanism.

METHODS

Five-week-old Sprague-Dawley rats were randomly divided into 2 groups: left atrial stenosis and sham-operated control. Echocardiography was performed 2, 4, 6, and 10 weeks after surgery, and cardiac catheterization and organ excision were subsequently performed at 10 weeks after surgery.

RESULTS

Left ventricular inflow velocity, measured by echocardiography, significantly increased in the left atrial stenosis group compared with that in the sham-operated control group (2.2 m/s, interquartile range [IQR], 1.9-2.2 and 1.1 m/s, IQR, 1.1-1.2, P < .01), and the right ventricular pressure-to-left ventricular systolic pressure ratio significantly increased in the left atrial stenosis group compared with the sham-operated control group (0.52, IQR, 0.54-0.60 and 0.22, IQR, 0.15-0.27, P < .01). The right ventricular weight divided by body weight was significantly greater in the left atrial stenosis group than in the sham-operated control group (0.54 mg/g, IQR, 0.50-0.59 and 0.39 mg/g, IQR, 0.38-0.43, P < .01). Histologic examination revealed medial hypertrophy of the pulmonary vein was thickened by 1.6 times in the left atrial stenosis group compared with the sham-operated control group. DNA microarray analysis and real-time polymerase chain reaction revealed that transforming growth factor-β mRNA was significantly elevated in the left atrial stenosis group. The protein levels of transforming growth factor-β and endothelin-1 were increased in the lung of the left atrial stenosis group by Western blot analyses.

CONCLUSIONS

We successfully established a novel, feasible rat model of pulmonary hypertension due to left heart diseases by generating left atrial stenosis. Although pulmonary hypertension was moderate, the pulmonary hypertension due to left heart diseases model rats demonstrated characteristic intrapulmonary venous arterialization and should be used to further investigate the mechanism of pulmonary hypertension due to left heart diseases.

Human Pericardial Fluid Contains Exosomes Enriched with Cardiovascular-Expressed MicroRNAs and Promotes Therapeutic Angiogenesis

The pericardial fluid (PF) is contained in the pericardial sac surrounding the heart. MicroRNA (miRNA) exchange via exosomes (endogenous nanoparticles) contributes to cell-to-cell communication. We investigated the hypotheses that the PF is enriched with miRNAs secreted by the heart and that it mediates vascular responses through exosome exchange of miRNAs. The study was developed using leftover material from aortic valve surgery. We found that in comparison with peripheral plasma, the PF contains exosomes enriched with miRNAs co-expressed in patients' myocardium and vasculature. At a functional level, PF exosomes improved survival, proliferation, and networking of cultured endothelial cells (ECs) and restored the angiogenic capacity of ECs depleted (via Dicer silencing) of their endogenous miRNA content. Moreover, PF exosomes improved post-ischemic blood flow recovery and angiogenesis in mice. Mechanistically, (1) let-7b-5p is proangiogenic and inhibits its target gene, TGFBR1, in ECs; (2) PF exosomes transfer a functional let-7b-5p to ECs, thus reducing their TGFBR1 expression; and (3) let-7b-5p depletion in PF exosomes impairs the angiogenic response to these nanoparticles. Collectively, our data support the concept that PF exosomes orchestrate vascular repair via miRNA transfer.

Transforming growth factor beta 1 induced endothelin-1 release is peroxisome proliferator-activated receptor gamma dependent in A549 cells

Background

Endothelin-1 (ET-1) is involved in pulmonary vascular remodeling. The aim of this study was to investigate the biochemical interactions between PPAR-γ, TGF-β1 and ET-1 in vitro.

Methods

A549 cells were pre-treated with S2505 (10 μM), S2871 (10 μM) with/without SB203580 (10 μM) for 60 min following 2 h treatment with 10 ng/mL TGF-β1. A549 cells were also transfected with positive or negative PPAR-γ plasmids for comparison. RT-PCR, ELISA, western blotting and confocal laser scanning microscopy (CLSM) were used to measure the relevant expression of mRNA, protein, mediators of pathways and nuclear factor translocation.

Results

SB203580 inhibited TGF-β1 induced ET-1 expression in A549 cells. S2871 decreased PPAR-γ mRNA and increase TGF-β1-induced ET-1 expression. S2871 increased phosphorylation of p38 MAPK and Smad2. Cells transfected with PPAR-γ negative plasmid increased TGF-β1 induced ET-1 expression, and increased the expression of phospho-p38 MAPK and phospho-Smad2. S2505 increased PPAR-γ mRNA expression, suppressed the increased TGF-β1-induced expression of ET-1. S2505 inhibited TGF-β1 induced phosphorylation of p38 MAPK and Smad2, also the nuclear translocation of Smad2. Cells transfected with PPAR-γ positive plasmid reduced TGF-β1-induced ET-1 expression, and inhibited the expression of phospho-p38 MAPK and phospho-Smad2.

Conclusions

TGF-β1 induced release of endothelin-1 is PPAR-γ dependent in cultured A549 cells.

Endothelin

The endothelins comprise three structurally similar 21-amino acid peptides. Endothelin-1 and -2 activate two G-protein coupled receptors, ETA and ETB, with equal affinity, whereas endothelin-3 has a lower affinity for the ETA subtype. Genes encoding the peptides are present only among vertebrates. The ligand-receptor signaling pathway is a vertebrate innovation and may reflect the evolution of endothelin-1 as the most potent vasoconstrictor in the human cardiovascular system with remarkably long lasting action. Highly selective peptide ETA and ETB antagonists and ETB agonists together with radiolabeled analogs have accurately delineated endothelin pharmacology in humans and animal models, although surprisingly no ETA agonist has been discovered. ET antagonists (bosentan, ambrisentan) have revolutionized the treatment of pulmonary arterial hypertension, with the next generation of antagonists exhibiting improved efficacy (macitentan). Clinical trials continue to explore new applications, particularly in renal failure and for reducing proteinuria in diabetic nephropathy. Translational studies suggest a potential benefit of ETB agonists in chemotherapy and neuroprotection. However, demonstrating clinical efficacy of combined inhibitors of the endothelin converting enzyme and neutral endopeptidase has proved elusive. Over 28 genetic modifications have been made to the ET system in mice through global or cell-specific knockouts, knock ins, or alterations in gene expression of endothelin ligands or their target receptors. These studies have identified key roles for the endothelin isoforms and new therapeutic targets in development, fluid-electrolyte homeostasis, and cardiovascular and neuronal function. For the future, novel pharmacological strategies are emerging via small molecule epigenetic modulators, biologicals such as ETB monoclonal antibodies and the potential of signaling pathway biased agonists and antagonists.

The TGF-β pathway mediates doxorubicin effects on cardiac endothelial cells

Elevated ALK4/5 ligands including TGF-β and activins have been linked to cardiovascular remodeling and heart failure. Doxorubicin (Dox) is commonly used as a model of cardiomyopathy, a condition that often precedes cardiovascular remodeling and heart failure. In 7-8-week-old C57Bl/6 male mice treated with Dox we found decreased capillary density, increased levels of ALK4/5 ligand and Smad2/3 transcripts, and increased expression of Smad2/3 transcriptional targets. Human cardiac microvascular endothelial cells (HCMVEC) treated with Dox also showed increased levels of ALK4/5 ligands, Smad2/3 transcriptional targets, a decrease in proliferation and suppression of vascular network formation in a HCMVEC and human cardiac fibroblasts co-culture assay. Our hypothesis is that the deleterious effects of Dox on endothelial cells are mediated in part by the activation of the TGF-β pathway. We used the inhibitor of ALK4/5 kinases SB431542 (SB) in concert with Dox to ascertain the role of TGF-β pathway activation in doxorubicin induced endothelial cell defects. SB prevented the suppression of HCMVEC proliferation in the presence of TGF-β2 and activin A, and alleviated the inhibition of HCMVEC proliferation by Dox. SB also prevented the suppression of vascular network formation in co-cultures of HCMVEC and human cardiac fibroblasts treated with Dox. Our results show that the inhibition of the TGF-β pathway alleviates the detrimental effects of Dox on endothelial cells in vitro.

Icariside II ameliorates diabetic nephropathy in streptozotocin-induced diabetic rats

Purpose

To investigate the therapeutic effects and potential mechanisms of icariside II (ICA II) on reversing diabetic nephropathy in streptozotocin (STZ)-induced type I diabetic rats.

Methods

Newborn male Sprague Dawley rats were labeled with thymidine analog 5-ethynyl-2-deoxyuridine (EdU) for tracking endogenous label retaining progenitor cells (LRCs). At age of 8 weeks, 48 rats were randomly divided into three groups: normal control group (n=16), diabetes mellitus group (DM; n=16), and diabetes mellitus plus ICA II therapy group (DM+ICA II, n=16). Eight weeks induced for diabetes with STZ, rats in DM group and DM+ICA II group were treated with vehicle or ICA II (5 mg/kg/day) for another 8 weeks, respectively. Then, blood creatinine, 24-hour urine protein, blood urea nitrogen, and glycosylated hemoglobin were measured, as well as the expression of von Willebrand factor, malondialdehyde, transforming growth factor-β/drosophila mothers against decapentaplegic protein/connective tissue growth factor (TGF-β/Smad/CTGF) signaling, marker of proliferation Ki-67, and EdU+ LRCs in renal tissues.

Results

Increased levels of creatinine, 24-hour urine protein, and blood urea nitrogen and remarkably decreased proportion of normal glomeruli and increased proportions of I, IIa, IIb, and III glomeruli were observed in diabetic rats, while ICA II could reverse these changes. Interestingly, ICA II could significantly downregulate the levels of malondialdehyde and TGF-β/Smad/CTGF signaling and increase the expression of von Willebrand factor, Ki-67, and EdU+ LRCs in the kidney.

Conclusion

ICA II treatment could ameliorate diabetic nephropathy in STZ-induced diabetic rats by increasing endothelial cell contents, downregulating TGF-β/Smad/CTGF signaling pathway and oxidative stress level, and promoting cell proliferation both in kidney cortex and medulla. These beneficial effects appear to be mediated by its antioxidant capacity and recruitment of endogenous EdU+ progenitor cells into the kidney tissue.

Role of secreted modular calcium-binding protein 1 (SMOC1) in transforming growth factor β signalling and angiogenesis

AIMS

Secreted modular calcium-binding protein 1 (SMOC1) is a matricellular protein that potentially interferes with growth factor receptor signalling. The aim of this study was to determine how its expression is regulated in endothelial cells and its role in the regulation of endothelial cell function.

METHODS AND RESULTS

SMOC1 was expressed by native murine endothelial cells as well as by cultured human, porcine, and murine endothelial cells. SMOC1 expression in cultured cells was increased by hypoxia via the down-regulation of miR-223, and SMOC1 expression was increased in lungs from miR-223-deficient mice. Silencing SMOC1 (small interfering RNA) attenuated endothelial cell proliferation, migration, and sprouting in in vitro angiogenesis assays. Similarly endothelial cell sprouting from aortic rings ex vivo as well as postnatal retinal angiogenesis in vivo was attenuated in SMOC1(+/-) mice. In endothelial cells, transforming growth factor (TGF)-β signalling via activin-like kinase (ALK) 5 leads to quiescence, whereas TGF-β signalling via ALK1 results in endothelial cell activation. SMOC1 acted as a negative regulator of ALK5/SMAD2 signalling, resulting in altered α2 integrin levels. Mechanistically, SMOC1 associated (immunohistochemistry, proximity ligation assay, and co-immunoprecipitation) with endoglin; an endothelium-specific type III auxiliary receptor for the TGF-β super family and the effects of SMOC1 down-regulation on SMAD2 phosphorylation were abolished by the down-regulation of endoglin.

CONCLUSION

These results indicate that SMOC1 is an ALK5 antagonist produced by endothelial cells that tips TGF-β signalling towards ALK1 activation, thus promoting endothelial cell proliferation and angiogenesis.

ALK5 and ALK1 play antagonistic roles in transforming growth factor β-induced podosome formation in aortic endothelial cells

Transforming growth factor β (TGF-β) and related cytokines play a central role in the vascular system. In vitro, TGF-β induces aortic endothelial cells to assemble subcellular actin-rich structures specialized for matrix degradation called podosomes. To explore further this TGF-β-specific response and determine in which context podosomes form, ALK5 and ALK1 TGF-β receptor signaling pathways were investigated in bovine aortic endothelial cells. We report that TGF-β drives podosome formation through ALK5 and the downstream effectors Smad2 and Smad3. Concurrent TGF-β-induced ALK1 signaling mitigates ALK5 responses through Smad1. ALK1 signaling induced by BMP9 also antagonizes TGF-β-induced podosome formation, but this occurs through both Smad1 and Smad5. Whereas ALK1 neutralization brings ALK5 signals to full potency for TGF-β-induced podosome formation, ALK1 depletion leads to cell disturbances not compatible with podosome assembly. Thus, ALK1 possesses passive and active modalities. Altogether, our results reveal specific features of ALK1 and ALK5 signaling with potential clinical implications.

Differentially expressed plasma microRNAs and the potential regulatory function of Let-7b in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a progressive disease characterized by misguided thrombolysis and remodeling of pulmonary arteries. MicroRNAs are small non-coding RNAs involved in multiple cell processes and functions. During CTEPH, circulating microRNA profile endued with characteristics of diseased cells could be identified as a biomarker, and might help in recognition of pathogenesis. Thus, in this study, we compared the differentially expressed microRNAs in plasma of CTEPH patients and healthy controls and investigated their potential functions. Microarray was used to identify microRNA expression profile and qRT-PCR for validation. The targets of differentially expressed microRNAs were identified in silico, and the Gene Ontology database and Kyoto Encyclopedia of Genes and Genomes pathway database were used for functional investigation of target gene profile. Targets of let-7b were validated by fluorescence reporter assay. Protein expression of target genes was determined by ELISA or western blotting. Cell migration was evaluated by wound healing assay. The results showed that 1) thirty five microRNAs were differentially expressed in CTEPH patients, among which, a signature of 17 microRNAs, which was shown to be related to the disease pathogenesis by in silico analysis, gave diagnostic efficacy of both sensitivity and specificity >0.9. 2) Let-7b, one of the down-regulated anti-oncogenic microRNAs in the signature, was validated to decrease to about 0.25 fold in CTEPH patients. 3) ET-1 and TGFBR1 were direct targets of let-7b. Altering let-7b level influenced ET-1 and TGFBR1 expression in pulmonary arterial endothelial cells (PAECs) as well as the migration of PAECs and pulmonary arterial smooth muscle cells (PASMCs). These results suggested that CTEPH patients had aberrant microRNA signature which might provide some clue for pathogenesis study and biomarker screening. Reduced let-7b might be involved in the pathogenesis of CTEPH by affecting ET-1 expression and the function of PAECs and PASMCs.

Key role of the endothelial TGF-β/ALK1/endoglin signaling pathway in humans and rodents pulmonary hypertension

Mutations affecting transforming growth factor-beta (TGF-β) superfamily receptors, activin receptor-like kinase (ALK)-1, and endoglin (ENG) occur in patients with pulmonary arterial hypertension (PAH). To determine whether the TGF-β/ALK1/ENG pathway was involved in PAH, we investigated pulmonary TGF-β, ALK1, ALK5, and ENG expressions in human lung tissue and cultured pulmonary-artery smooth-muscle-cells (PA-SMCs) and pulmonary endothelial cells (PECs) from 14 patients with idiopathic PAH (iPAH) and 15 controls. Seeing that ENG was highly expressed in PEC, we assessed the effects of TGF-β on Smad1/5/8 and Smad2/3 activation and on growth factor production by the cells. Finally, we studied the consequence of ENG deficiency on the chronic hypoxic-PH development by measuring right ventricular (RV) systolic pressure (RVSP), RV hypertrophy, and pulmonary arteriolar remodeling in ENG-deficient (Eng+/-) and wild-type (Eng+/+) mice. We also evaluated the pulmonary blood vessel density, macrophage infiltration, and cytokine expression in the lungs of the animals. Compared to controls, iPAH patients had higher serum and pulmonary TGF-β levels and increased ALK1 and ENG expressions in lung tissue, predominantly in PECs. Incubation of the cells with TGF-β led to Smad1/5/8 phosphorylation and to a production of FGF2, PDGFb and endothelin-inducing PA-SMC growth. Endoglin deficiency protected mice from hypoxic PH. As compared to wild-type, Eng+/- mice had a lower pulmonary vessel density, and no change in macrophage infiltration after exposure to chronic hypoxia despite the higher pulmonary expressions of interleukin-6 and monocyte chemoattractant protein-1. The TGF-β/ALK1/ENG signaling pathway plays a key role in iPAH and experimental hypoxic PH via a direct effect on PECs leading to production of growth factors and inflammatory cytokines involved in the pathogenesis of PAH.

Grape seed pro-anthocyanidins ameliorates radiation-induced lung injury

Radiation-induced lung injury (RILI) is a potentially fatal and dose-limiting complication of thoracic radiotherapy. This study was to investigate the protective effects of grape seed pro-anthocyanidins (GSPs), an efficient antioxidant and anti-carcinogenic agent, on RILI. In our study, it was demonstrated that acute and late RILI was ameliorated after GSPs treatment possibly through suppressing TGF-β1/Smad3/Snail signalling pathway and modulating the levels of cytokines (interferon-γ, IL-4 and IL-13) derived from Th1/Th2 cells. In addition, a sustained high level of PGE2 was also maintained by GSPs treatment to limited fibroblast functions. As shown by electron spin resonance spectrometry, GSPs could scavenge hydroxyl radical (•OH) in a dose-dependent manner, which might account for the mitigation of lipid peroxidation and consequent apoptosis of lung cells. In vitro, GSPs radiosensitized lung cancer cell A549 while mitigating radiation injury on normal alveolar epithelial cell RLE-6TN. In conclusion, the results showed that GSPs protects mice from RILI through scavenging free radicals and modulating RILI-associated cytokines, suggesting GSPs as a novel protective agent in RILI.

Effect of placenta secretory products on migration activity of endothelial EA.Hy926 cells

We studied the influence of factors secreted by the placenta in physiological and preeclampsia-complicated pregnancy on migration activity of endothelial EA.Hy926 cells. It was found that migration of endothelial cells was more intensive in the presence of secretory factors from trimester I placentas in comparison with trimester III placentas and was lower in the presence of placental factors in preeclampsia in comparison with physiological pregnancy.

Over, and underexpression of endothelin 1 and TGF-beta family ligands and receptors in lung tissue of broilers with pulmonary hypertension

Transforming growth factor beta (TGF β ) is a family of genes that play a key role in mediating tissue remodeling in various forms of acute and chronic lung disease. In order to assess their role on pulmonary hypertension in broilers, we determined mRNA expression of genes of the TGF β family and endothelin 1 in lung samples from 4-week-old chickens raised either under normal or cold temperature conditions. Both in control and cold-treated groups of broilers, endothelin 1 mRNA expression levels in lungs from ascitic chickens were higher than levels from healthy birds (P < 0.05), whereas levels in animals with cardiac failure were intermediate. Conversely, TGF β 2 and TGF β 3 gene expression in lungs were higher in healthy animals than in ascitic animals in both groups (P < 0.05). TGF β 1, T β RI, and T β RII mRNA gene expression among healthy, ascitic, and chickens with cardiac failure showed no differences (P > 0.05). BAMBI mRNA gene expression was lowest in birds with ascites only in the control group as compared with the values from healthy birds (P < 0.05).

Effectiveness of intracavernous delivery of adenovirus encoding Smad7 gene on erectile function in a mouse model of cavernous nerve injury

INTRODUCTION

Men with erectile dysfunction (ED) respond poorly to oral phosphodiesterase-5 inhibitors following radical prostatectomy. Recent studies have reported that up-regulation of transforming growth factor-β1 (TGF-β1) and activation of the Smad signaling pathway play important roles in cavernous fibrosis and in the deterioration of erectile function in a mouse model of cavernous nerve injury (CNI) and in patients with spinal cord injury. The mothers against decapentaplegic homolog 7 (Smad7) is known to inhibit the phosphorylation of Smad2 and Smad3.

AIM

To investigate the effectiveness of adenoviruses encoding Smad7 gene (Ad-Smad7) on erectile function in a mouse model of CNI.

METHODS

Twelve-week-old C57BL/6J mice were used and distributed into 7 groups: sham operation group, untreated CNI group, and CNI groups receiving a single intracavernous injection of adenovirus encoding LacZ (1 × 10(8) virus particles [vp]/20 μL) or adenovirus encoding Smad7 (Ad-Smad7; 1 × 10(7), 1 × 10(8), 2 × 10(8), or 1 × 10(9) vp/20 μL).

MAIN OUTCOME MEASURES

Two weeks after bilateral cavernous nerve crushing and treatment, erectile function was measured by electrical stimulation of the cavernous nerve. The penis was harvested for histologic examinations and Western blot analysis.

RESULTS

The highest erectile response was noted in CNI mice treated with Ad-Smad7 at a dose of 1 × 10(8)  vp, which reached up to 82-85% of sham control values. Local delivery of Ad-Smad7 significantly decreased endothelial cell apoptosis and the production of extracellular matrix proteins, including plasminogen activator inhibitor-1, fibronectin, collagen I, and collagen IV, and induced endothelial nitric oxide synthase phosphorylation in the corpus cavernosum tissue of CNI mice.

CONCLUSION

The adenovirus-mediated gene transfer of Smad7 successfully restored erectile function by enhancing endothelial cell function and through antifibrotic effects. These findings suggest that inhibition of the TGF-β signaling pathway by use of Smad7 may represent a promising therapeutic strategy for ED induced by radical prostatectomy.

The ALK-1/Smad1 pathway in cardiovascular physiopathology. A new target for therapy?

Activin receptor-like kinase-1 or ALK-1 is a type I cell surface receptor for the transforming growth factor-β (TGF-β) family of proteins. The role of ALK-1 in endothelial cells biology and in angiogenesis has been thoroughly studied by many authors. However, it has been recently suggested a possible role of ALK-1 in cardiovascular homeostasis. ALK-1 is not only expressed in endothelial cells but also in smooth muscle cells, myofibroblast, hepatic stellate cells, chondrocytes, monocytes, myoblasts, macrophages or fibroblasts, but its role in these cells have not been deeply analyzed. Due to the function of ALK-1 in these cells, this receptor plays a role in several cardiovascular diseases. Animals with ALK-1 haploinsufficiency and patients with mutations in Acvrl1 (the gene that codifies for ALK-1) develop type-2 Hereditary Hemorrhagic Telangiectasia. Moreover, ALK-1 heterozygous mice develop pulmonary hypertension. Higher levels of ALK-1 have been observed in atherosclerotic plaques, suggesting a possible protector role of this receptor. ALK-1 deficiency is also related to the development of arteriovenous malformations (AVMs). Besides, due to the ability of ALK-1 to regulate cell proliferation and migration, and to modulate extracellular matrix (ECM) protein expression in several cell types, ALK-1 has been now demonstrated to play an important role in cardiovascular remodeling. In this review, we would like to offer a complete vision of the role of ALK-1 in many process related to cardiovascular homeostasis, and the involvement of this protein in the development of cardiovascular diseases, suggesting the possibility of using the ALK-1/smad-1 pathway as a powerful therapeutic target.

Fenofibrate Inhibits Endothelin-1 Expression by Peroxisome Proliferator–Activated Receptor α–Dependent and Independent Mechanisms in Human Endothelial Cells

Objective—

Dyslipidemia contributes to endothelial dysfunction in type 2 diabetes mellitus. Fenofibrate (FF), a ligand of the peroxisome proliferator–activated receptor-α (PPARα), has beneficial effects on microvascular complications. FF may act on the endothelium by regulating vasoactive factors, including endothelin-1 (ET-1). In vitro, FF decreases ET-1 expression in human microvascular endothelial cells. We investigated the molecular mechanisms involved in the effect of FF treatment on plasma levels of ET-1 in type 2 diabetes mellitus patients.

Methods and Results—

FF impaired the capacity of transforming growth factor-β to induce ET-1 gene expression. PPARα activation by FF increased expression of the transcriptional repressor Krüppel-like factor 11 and its binding to the ET-1 gene promoter. Knockdown of Krüppel-like factor 11 expression potentiated basal and transforming growth factor-β–stimulated ET-1 expression, suggesting that Krüppel-like factor 11 downregulates ET-1 expression. FF, in a PPARα-independent manner, and insulin enhanced glycogen synthase kinase-3β phosphorylation thus reducing glycogen synthase kinase-3 activity that contributes to the FF-mediated reduction of ET-1 gene expression. In type 2 diabetes mellitus, improvement of flow-mediated dilatation of the brachial artery by FF was associated with a decrease in plasma ET-1.

Conclusion—

FF decreases ET-1 expression by a PPARα-dependent mechanism, via transcriptional induction of the Krüppel-like factor 11 repressor and by PPARα-independent actions via inhibition of glycogen synthase kinase-3 activity.

ALK2 and BMPR2 knockdown and endothelin-1 production by pulmonary microvascular endothelial cells

BACKGROUND

Many cases of pulmonary arterial hypertension (PAH) are heritable and related to gene mutations in bone morphogenic receptor-2 (BMPR2). These patients consequently may have a signaling imbalance within the transforming growth factor beta (TGFβ) receptor superfamily. The causes of increased endothelin-1 (ET-1), which contributes to PAH, are unknown, and we therefore studied the contribution of various BMPs and their receptors on ET-1 production in vitro, after knockdown of BMPR2 in human pulmonary microvascular endothelial cells (HMVEC-LBl).

METHODOLOGY/PRINCIPAL FINDINGS

Receptor knockdown in HMVEC-LBl was performed using siRNA to BMPR2, and activin like-kinases 1 and 2 (ALK1, ALK2). ET-1 and TGFβ levels in the medium were measured by ELISA. In some experiments, cells were exposed to TGFβ or BMP7 or FK506 (tacrolimus). Using Western blotting, levels of BMPR2, endothelin ET(B) receptor, phosphorylated SMAD 2 (pSMAD 2), phosphorylated SMAD 1,5 (pSMAD 1,5), ALK1, ALK2, ALK5, TGFβ receptor 2, plasminogen activator inhibitor-1 (PAI-1) and ID1 were measured. BMPR2 knockdown significantly increased ET-1 levels. It did not affect ET(B) receptor or TGFβ levels. TGFβ increased ET-1 levels, with or without BMPR2 knockdown. BMPR2 knockdown did not affect TGFβ (pSMAD 2 and PAI-1) signaling. BMP7 increased ET-1 levels after BMPR2 knockdown but this was prevented by ALK2 knockdown as was the increase in ID1 caused by BMPR2 knockdown. FK506, which interacts with ALK2, increased ET-1 levels and ID1 levels, and this was blocked by ALK2 knockdown.

CONCLUSION/SIGNIFICANCE

ALK2 may be an important receptor in ET-1 production during BMPR2 knockdown.

The complex regulation of TGF-β in cardiovascular disease

Transforming growth factor β (TGF-β1) is a pleiotropic cytokine with many and complex effects in cell and tissue physiology. This is made possible by a very complex and interwoven signaling system, whose regulation continues to be the focus of a growing line of research. This complex regulation translates to a key role in cardiovascular physiology, hemostasis, and the blood–vessel interface. In accordance with this, the TGF-β1 pathway appears to be deregulated in related disorders, such as atherosclerotic vascular disease and myeloproliferative syndromes. It is expected that the growing amount of experimental and clinical research will yield medical advances in the applications of knowledge of the TGF-β1 pathway to diagnosis and therapeutics.

APC and Smad7 link TGFβ type I receptors to the microtubule system to promote cell migration

Cell migration occurs by activation of complex regulatory pathways that are spatially and temporally integrated in response to extracellular cues. Binding of adenomatous polyposis coli (APC) to the microtubule plus ends in polarized cells is regulated by glycogen synthase kinase 3β (GSK-3β). This event is crucial for establishment of cell polarity during directional migration. However, the role of APC for cellular extension in response to extracellular signals is less clear. Smad7 is a direct target gene for transforming growth factor-β (TGFβ) and is known to inhibit various TGFβ-induced responses. Here we report a new function for Smad7. We show that Smad7 and p38 mitogen-activated protein kinase together regulate the expression of APC and cell migration in prostate cancer cells in response to TGFβ stimulation. In addition, Smad7 forms a complex with APC and acts as an adaptor protein for p38 and GSK-3β kinases to facilitate local TGFβ/p38-dependent inactivation of GSK-3β, accumulation of β-catenin, and recruitment of APC to the microtubule plus end in the leading edge of migrating prostate cancer cells. Moreover, the Smad7-APC complex links the TGFβ type I receptor to the microtubule system to regulate directed cellular extension and migratory responses evoked by TGFβ.

Critical role of hydrogen peroxide signaling in the sequential activation of p38 MAPK and eNOS in laminar shear stress

Laminar shear stress (LSS) is a protective hemodynamic regulator of endothelial function and limits the development of atherosclerosis and other vascular wall diseases related to pathophysiological generation of reactive oxygen species. LSS activates several endothelial signaling responses, including the activation of MAPKs and eNOS. Here, we explored the mechanisms of activation of these key endothelial signaling pathways. Using the cone/plate model we found that LSS (12 dyn/cm(2)) rapidly promotes endothelial intracellular generation of superoxide and hydrogen peroxide (H(2)O(2)). Physiological concentrations of H(2)O(2) (flux of 0.1 nM/min and 15 μM added extracellularly) significantly activated both eNOS and p38 MAPK. Pharmacological inhibition of NADPH oxidases (NOXs) and specific knockdown of NOX4 decreased LSS-induced p38 MAPK activation. Whereas the absence of eNOS did not alter LSS-induced p38 MAPK activation, pharmacological inhibition and knockdown of p38α MAPK blocked H(2)O(2)- and LSS-induced eNOS phosphorylation and reduced (•)NO levels. We propose a model in which LSS promotes the formation of signaling levels of H(2)O(2), which in turn activate p38α MAPK and then stimulate eNOS, leading to increased (•)NO generation and protection of endothelial function.

BMP-9 induced endothelial cell tubule formation and inhibition of migration involves Smad1 driven endothelin-1 production

BACKGROUND

Bone morphogenetic proteins (BMPs) and their receptors, such as bone morphogenetic protein receptor (BMPR) II, have been implicated in a wide variety of disorders including pulmonary arterial hypertension (PAH). Similarly, endothelin-1 (ET-1), a mitogen and vasoconstrictor, is upregulated in PAH and endothelin receptor antagonists are used in its treatment. We sought to determine whether there is crosstalk between BMP signalling and the ET-1 axis in human pulmonary artery endothelial cells (HPAECs), possible mechanisms involved in such crosstalk and functional consequences thereof.

METHODOLOGY/PRINCIPAL FINDING

Using western blot, real time RT-PCR, ELISA and small RNA interference methods we provide evidence that in HPAECs BMP-9, but not BMP-2, -4 and -6 significantly stimulated ET-1 release under physiological concentrations. This release is mediated by both Smad1 and p38 MAPK and is independent of the canonical Smad4 pathway. Moreover, knocking down the ALK1 receptor or BMPR II attenuates BMP-9 stimulated ET-1 release, whilst causing a significant increase in prepro ET-1 mRNA transcription and mature peptide release. Finally, BMP-9 induced ET-1 release is involved in both inhibition of endothelial cell migration and promotion of tubule formation.

CONCLUSIONS/SIGNIFICANCE

Although our data does not support an important role for BMP-9 as a source of increased endothelial ET-1 production seen in human PAH, BMP-9 stimulated ET-1 production is likely to be important in angiogenesis and vascular stability. However, increased ET-1 production by endothelial cells as a consequence of BMPR II dysfunction may be clinically relevant in the pathogenesis of PAH.

TGFβ signaling and cardiovascular diseases

Transforming growth factor β (TGFβ) family members are involved in a wide range of diverse functions and play key roles in embryogenesis, development and tissue homeostasis. Perturbation of TGFβ signaling may lead to vascular and other diseases. In vitro studies have provided evidence that TGFβ family members have a wide range of diverse effects on vascular cells, which are highly dependent on cellular context. Consistent with these observations genetic studies in mice and humans showed that TGFβ family members have ambiguous effects on the function of the cardiovascular system. In this review we discuss the recent advances on TGFβ signaling in (cardio)vascular diseases, and describe the value of TGFβ signaling as both a disease marker and therapeutic target for (cardio)vascular diseases.