Angiotensin II modulates VEGF-driven angiogenesis by opposing effects of type 1 and type 2 receptor stimulation in the microvascular endothelium

Targeting the Renin-angiotensin-aldosterone System (RAAS) for Cardiovascular Protection and Enhanced Oncological Outcomes: Review

OPINION STATEMENT

The renin-angiotensin-aldosterone system (RAAS) is a crucial regulator of the cardiovascular system and a target for widely used therapeutic drugs. Dysregulation of RAAS, implicated in prevalent diseases like hypertension and heart failure, has recently gained attention in oncological contexts due to its role in tumor biology and cardiovascular toxicities (CVTs). Thus, RAAS inhibitors (RAASi) may be used as potential supplementary therapies in cancer treatment and CVT prevention. Oncological treatments have evolved significantly, impacting patient survival and safety profiles. However, they pose cardiovascular risks, necessitating strategies for mitigating adverse effects. The main drug classes used in oncology include anthracyclines, anti-HER2 therapies, immune checkpoint inhibitors (ICIs), and vascular endothelial growth factor (VEGF) signaling pathway inhibitors (VSPI). While effective against cancer, these drugs induce varying CVTs. RAASi adjunctive therapy shows promise in enhancing clinical outcomes and protecting the cardiovascular system. Understanding RAAS involvement in cancer and CVT can inform personalized treatment approaches and improve patient care.

Endoplasmic reticulum stress-a key guardian in cancer

Endoplasmic reticulum stress (ERS) is a cellular stress response characterized by excessive contraction of the endoplasmic reticulum (ER). It is a pathological hallmark of many diseases, such as diabetes, obesity, and neurodegenerative diseases. In the unique growth characteristic and varied microenvironment of cancer, high levels of stress are necessary to maintain the rapid proliferation and metastasis of tumor cells. This process is closely related to ERS, which enhances the ability of tumor cells to adapt to unfavorable environments and promotes the malignant progression of cancer. In this paper, we review the roles and mechanisms of ERS in tumor cell proliferation, apoptosis, metastasis, angiogenesis, drug resistance, cellular metabolism, and immune response. We found that ERS can modulate tumor progression via the unfolded protein response (UPR) signaling of IRE1, PERK, and ATF6. Targeting the ERS may be a new strategy to attenuate the protective effects of ERS on cancer. This manuscript explores the potential of ERS-targeted therapies, detailing the mechanisms through which ERS influences cancer progression and highlighting experimental and clinical evidence supporting these strategies. Through this review, we aim to deepen our understanding of the role of ER stress in cancer development and provide new insights for cancer therapy.

Angiotensin II - AT1 receptor signalling regulates the plasminogen-plasmin system in human stromal endometrial cells increasing extracellular matrix degradation, cell migration and inducing a proinflammatory profile

The pivotal role of human endometrial stromal cells (hESCs) in the development of endometriosis lies in their ability to adopt a pro-invasive and proinflammatory profile upon migration to areas outside the uterus. However, the molecular mechanisms involved in these events remain unclear. In this study, we investigated how angiotensin II (Ang II) affects the plasminogen-plasmin system in hESCs, and the mechanisms underlying cell proliferation, migration, matrix degradation, and inflammation. Precursors, receptors, and peptidases involved in angiotensin metabolism increased significantly in Ang II-treated hESCs. The expression and activity of tissue (tPA)- and urokinase (uPA)- type plasminogen activators and the receptor for uPA (uPAR) were induced in the presence of Ang II. The up-regulation of tPA-uPA/uPAR pathway significantly contributes to heightened plasmin production both on the surface of hESCs and in their conditioned media. As a result, the plasmin generation induced by Ang II enhances the degradation of fibrin and matrix proteins, while also boosting hESC viability, proliferation, and migration through the up-regulation of growth factor expression. Notably, Ang II-induced hESC migration was dependent on the generation of active plasmin on cell surface. Ang II regulates oxidative and inflammatory signalling in hESCs primarily via NADPH oxidase and through the up-regulation of proinflammatory cytokines and adhesion molecules. Interestingly, Ang II receptor (AT1R) blockage, decreased plasmin generation, tPA-uPA/uPAR expression and hESC migration. Our results suggest that Ang II/AT1R axis regulates hESC proliferation and migration through tPA-uPA/uPAR pathway activation and plasmin generation. We propose the Ang II/AT1R axis as a potential target for endometriosis treatment.

Lymphatic vessels and the renin-angiotensin-system

The lymphatic system is an integral part of the circulatory system and plays an important role in the fluid homeostasis of the human body. Accumulating evidence has recently suggested the involvement of lymphatic dysfunction in the pathogenesis of cardio-reno-vascular (CRV) disease. However, how the sophisticated contractile machinery of lymphatic vessels is modulated and, possibly impaired in CRV disease, remains largely unknown. In particular, little attention has been paid to the effect of the renin-angiotensin-system (RAS) on lymphatics, despite the high concentration of RAS mediators that these tissue-draining vessels are exposed to and the established role of the RAS in the development of classic microvascular dysfunction and overt CRV disease. We herein review recent studies linking RAS to lymphatic function and/or plasticity and further highlight RAS-specific signaling pathways, previously shown to drive adverse arterial remodeling and CRV organ damage that have potential for direct modulation of the lymphatic system.

Potential molecular and cellular mechanisms for adverse placental outcomes in pregnancies complicated by SARS-CoV-2 infection-A scoping review

BACKGROUND

Emerging evidence suggests that SARS-CoV-2 infection during pregnancy can result in placental damage and poor placental outcomes. However, the mechanisms by which SARS-CoV-2 infection leads to placental damage are not well understood. With a rapid expansion of literature on this topic, it is critical to assess the quality and synthesize the current state of literature. The objective of this scoping review is to highlight underlying mechanisms of SARS-CoV-2 mediated placental pathology in pregnant individuals and identify literature gaps regarding molecular and cellular mechanisms of poor placental outcomes.

METHODS

The review was conducted and reported following the recommendations of the PRISMA extension for Scoping Reviews. The study protocol was registered with Open Science Framework (https://osf.io/p563s/). Five databases (MEDLINE, EMBASE, Scopus, CINAHL, PubMed) were searched for studies published between September 2019 until April 2022. Studies assessing placental outcomes with respect to SARS-CoV-2 infection in pregnancy were eligible for inclusion. Outcomes of interest included histopathology, and molecular or cellular analysis. All records were uploaded into Covidence and extracted using the Joanna Briggs Institute method. Studies were assessed for risk of bias using the Newcastle Ottawa scale and a narrative synthesis of results was generated.

RESULTS

Twenty-seven studies reporting on molecular and/or cellular mechanisms of SARS-CoV-2 mediated placental outcomes were included in this review. SARS-CoV-2 infection was associated with perturbations in the ACE2 pathway, inflammatory mediators and immune cell populations and mitochondrial function in placentas.

CONCLUSIONS

Our findings suggest that changes in the ACE2 pathway, mitochondrial dysfunction, and/or inflammatory processes may lead to placental damage observed in SARS-CoV-2 infection during pregnancy. More research is needed to understand the role of these pathways further, in addition to data collection related to trimester, severity, and strain.

Microglia: The breakthrough to treat neovascularization and repair blood-retinal barrier in retinopathy

Microglia are the primary resident retinal macrophages that monitor neuronal activity in real-time and facilitate angiogenesis during retinal development. In certain retinal diseases, the activated microglia promote retinal angiogenesis in hypoxia stress through neurovascular coupling and guide neovascularization to avascular areas (e.g., the outer nuclear layer and macula lutea). Furthermore, continuously activated microglia secrete inflammatory factors and expedite the loss of the blood-retinal barrier which causes irreversible damage to the secondary death of neurons. In this review, we support microglia can be a potential cellular therapeutic target in retinopathy. We briefly describe the relevance of microglia to the retinal vasculature and blood-retinal barrier. Then we discuss the signaling pathway related to how microglia move to their destinations and regulate vascular regeneration. We summarize the properties of microglia in different retinal disease models and propose that reducing the number of pro-inflammatory microglial death and conversing microglial phenotypes from pro-inflammatory to anti-inflammatory are feasible for treating retinal neovascularization and the damaged blood-retinal barrier (BRB). Finally, we suppose that the unique properties of microglia may aid in the vascularization of retinal organoids.

Salvianolic acid B, a new type I IRE1 kinase inhibitor, abrogates AngII-induced angiogenesis by interacting with IRE1 in its active conformation

Angiotensin II (AngII)-mediated pathological angiogenesis is one of the important factors promoting the progression of atherosclerosis, tumour metastasis, and diabetic retinopathy. Here, we first demonstrate that salvianolic acid B (Sal B) attenuated AngII-induced angiogenesis by downregulating the IRE1/ASK1/JNK/p38MAPK signalling pathway and protected vascular endothelial cells from hypoxia-induced damage. These pharmacological consequences could be ascribed to the unique interactions between Sal B and the ATP-binding cavity of IREIα, leading to bi-directional roles of IRE1 kinase and endonuclease activity; this may possibly be one of the essential mechanisms of the bi-directional regulation of angiogenesis in different conditions. Moreover, our results indicated that IRE1 was a novel anti-angiogenesis target and type I IRE1 kinase inhibitor (e.g., Sal B, APY29) and might be a potentially eligible low-toxicity drug for treating AngII-mediated pathological angiogenesis.

Impact of renin-angiotensin system inhibitors on the survival of patients with rectal cancer

Background

Renin-angiotensin system inhibitors (RASIs) are widely used in the treatment of hypertension. However, their impact on the outcome of the combined treatment of rectal cancer is poorly understood. The aim of this study was to assess the effect of RASIs on the survival of rectal cancer patients with associated hypertension after neoadjuvant treatment and radical resection.

Methods

Between 2008 and 2016, 242 radical (R0) rectal resections for cancer were performed after neoadjuvant treatment in patients with associated hypertension. At the time of treatment, 158 patients were on RASIs, including 35 angiotensin-receptor antagonists (ARB) users and 123 angiotensin-converting enzyme inhibitors (ACEI) users. Eighty-four patients were on drugs other than RASIs (non-RASI users). The survival analysis was performed using the Kaplan–Meier estimator with the log-rank test and the Cox proportional hazards model.

Results

The log-rank test showed a significantly worse overall survival (OS) in the group of ACEI users compared to ARB users (p = 0.009) and non-RASI users (p = 0.013). Disease-free survival (DFS) was better in the group of ARB users compared to ACEI users. However, the difference was not statistically significant (p = 0.064). The Multivariate Cox analysis showed a significant beneficial effect of ARBs on OS (HR: 0.326, 95% CI: 0.147–0.724, p = 0.006) and ARBs on DFS (HR: 0.339, 95% CI: 0.135–0.850, p = 0.021) compared to ACEIs. Other factors affecting OS included age (HR: 1.044, 95% CI: 1.016–1.073, p = 0.002), regional lymph node metastasis (ypN +) (HR: 2.157, 95% CI: 1.395–3.334, p = 0.001) and perineural invasion (PNI) (HR: 3.864, 95% CI: 1.799–8.301, p = 0.001). Additional factors affecting DFS included ypN + (HR: 2.310, 95% CI: 1.374–3.883, p = 0.002) and PNI (HR: 4.351, 95% CI: 1.584–11.954, p = 0.004).

Conclusions

The use of ARBs instead of ACEIs may improve the outcome of the combined therapy for rectal cancer patients with associated hypertension.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09919-0.

Angiotensin-(1-9) in hypertension

Angiotensin-(1-9) [Ang-(1-9)] is a peptide of the non-canonical renin-angiotensin system (RAS) synthesized from angiotensin I by the monopeptidase angiotensin-converting enzyme type 2 (ACE2). Using osmotic minipumps, infusion of Ang-(1-9) consistently reduces blood pressure in several rat hypertension models. In these animals, hypertension-induced end-organ damage is also decreased. Several pieces of evidence suggest that Ang-(1-9) is the endogenous ligand that binds and activates the type-2 angiotensin II receptor (AT2R). Activation of AT2R triggers different tissue-specific signaling pathways. This phenomenon could be explained by the ability of AT2R to form different heterodimers with other G protein-coupled receptors. Because of the antihypertensive and protective effects of AT2R activation by Ang-(1-9), associated with a short half-life of RAS peptides, several synthetic AT2R agonists have been synthesized and assayed. Some of them, particularly CGP42112, C21 and novokinin, have demonstrated antihypertensive properties. Only two synthetic AT2R agonists, C21 and LP2-3, have been tested in clinical trials, but none of them like an antihypertensive. Therefore, Ang-(1-9) is a promising antihypertensive drug that reduces hypertension-induced end-organ damage. However, further research is required to translate this finding successfully to the clinic.

AT2R activation increases in vitro angiogenesis in pregnant human uterine artery endothelial cells

Angiogenesis is vital during pregnancy for remodeling and enhancing vasodilation of maternal uterine arteries, and increasing uterine blood flow. Abnormal angiogenesis is associated with decreased uteroplacental blood flow and development of pregnancy disorders such as gestational hypertension, preeclampsia, fetal growth restriction, preterm delivery, stillbirth, and miscarriage. The mechanisms that contribute to normal angiogenesis remain obscure. Our previous studies demonstrated that expression of the angiotensin type 2 receptor (AT2R) is increased while the angiotensin type 1 receptor (AT1R) is unchanged in the endothelium of uterine arteries, and that AT2R-mediated pregnancy adaptation facilitates enhanced vasodilation and uterine arterial blood flow. However, the role of AT2R in regulating angiogenesis during pregnancy has never been studied. This study examines whether or not AT2R activation induces angiogenesis and, if so, what mechanisms are involved. To this end, we used primary human uterine artery endothelial cells (hUAECs) isolated from pregnant and nonpregnant women undergoing hysterectomy. The present study shows that Compound 21, a selective AT2R agonist, induced proliferation of pregnant-hUAECs, but not nonpregnant-hUAECs, in a concentration-dependent manner, and that this C21-induced mitogenic effect was blocked by PD123319, a selective AT2R antagonist. The mitogenic effects induced by C21 were inhibited by blocking JNK—but not ERK, PI3K, and p38—signaling pathways. In addition, C21 concentration dependently increased cell migration and capillary-like tube formation in pregnant-hUAECs. The membrane-based antibody array showed that C21 increased expression of multiple angiogenic proteins, including EGF, bFGF, leptin, PLGF, IGF-1, and angiopoietins. Our qPCR analysis demonstrates that C21-induced increase in expression of these angiogenic proteins correlates with a proportional increase in mRNA expression, indicating that AT2R activates angiogenic proteins at the transcriptional level. In summary, the present study shows that AT2R activation induces angiogenesis of hUAECs in a pregnancy-specific manner through JNK-mediated pathways with associated transcriptional upregulation of multiple proangiogenic proteins.

Paradigms in chronic subdural hematoma pathophysiology: Current treatments and new directions

ABSTRACT

Chronic subdural hematomas (CSDHs) are an increasingly common pathology encountered in a neurosurgical trauma practice. Although the operative and nonoperative management of CSDH has been studied extensively, the recurrence rate of CSDH remains high, with no significant decrease in recent years. We undertook a detailed assessment of the known pathophysiological mechanisms by which CSDHs recur to improve our ability to treat patients with this disease successfully. In this review of the literature from the PubMed and Scopus databases, we used the search terms "(pathophysiology) AND chronic subdural hematoma [tiab]" to identify pertinent reviews and articles in English. The results demonstrated a complex inflammatory response to subdural blood, which begins with the formation of a collagen neomembrane around the clot itself. Proinflammatory mediators, such as vascular endothelial growth factor, interleukin-6, interleukin-8, tissue necrosis factor α, matrix metalloproteinases, and basic fibroblast growth factor, then contribute to chronic microbleeding by promoting the formation of fragile, leaky blood vessels, and widening of gap junctions of existing vessels. It is evident that the lack of improvement in recurrence rate is due to pathological factors that are not entirely alleviated by simple subdural evacuation. Targeted approaches, such as middle meningeal artery embolization and anti-inflammatory therapies, have become increasingly common and require further prospective analysis to aid in the determination of their efficacy.

Dual effects of atorvastatin on angiogenesis pathways in the differentiation of mesenchymal stem cells

Atorvastatin (ATO) can improve the transplantation efficacy of mesenchymal stem cells (MSCs) after acute myocardial infarction. The present study aimed at ATO effects on the angiogenesis-signaling pathways from MSCs' differentiation to tissue angiogenesis. MSCs were first prepared from BALB/c mouse bone marrow. MTT assay was then done for the biodegradability of MSCs with the extracellular matrix. After that, the differentiation of cells into the bone and fat tissues was confirmed by Alizarin and Oil Red O staining. The extracellular matrix was then combined with the cells to the implant. Animals were intraperitoneally treated with ATO (2 and 40 mg/kg, daily) three days before cell transplantation to one week after. Finally, the assays were carried out by electron microscopy, immunocytochemistry, ELISA, Western blot, and RT-qPCR techniques. A phase-contrast microscope confirmed the morphology of cells. The cell differentiation into bone and fat tissues was confirmed by Alizarin red staining and flow cytometry, and the cell proliferation was confirmed by MTT assay. Unlike ATO 40 mg/kg group, ATO 2 mg/kg was significantly increased the CD31, eNOS, podocalyxin, von Willibrand factor, and alpha-smooth muscle actin proteins levels compared to the control group in vitro experiment. The expression of CD31 and VEGF proteins, as angiogenesis markers, and Ki-67 protein, as a proliferation marker, was significantly higher in a low dose of ATO (2 mg/kg) than that of the control group in vivo experiment. Unlike ATO 40 mg/kg, the expression levels of ERK, AKT, NF-ҝB, Rho, STAT3, Ets-1, HIF-1α, and VEGF proteins and genes were significantly increased in ATO 2 mg/kg compared to the control. A low dose of ATO can be a beneficial tool in the function of MSCs and their differentiation to tissue angiogenesis.

Angiotensin II Induces Oxidative Stress and Endothelial Dysfunction in Mouse Ophthalmic Arteries via Involvement of AT1 Receptors and NOX2

Angiotensin II (Ang II) has been implicated in the pathophysiology of various age-dependent ocular diseases. The purpose of this study was to test the hypothesis that Ang II induces endothelial dysfunction in mouse ophthalmic arteries and to identify the underlying mechanisms. Ophthalmic arteries were exposed to Ang II in vivo and in vitro to determine vascular function by video microscopy. Moreover, the formation of reactive oxygen species (ROS) was quantified and the expression of prooxidant redox genes and proteins was determined. The endothelium-dependent artery responses were blunted after both in vivo and in vitro exposure to Ang II. The Ang II type 1 receptor (AT1R) blocker, candesartan, and the ROS scavenger, Tiron, prevented Ang II-induced endothelial dysfunction. ROS levels and NOX2 expression were increased following Ang II incubation. Remarkably, Ang II failed to induce endothelial dysfunction in ophthalmic arteries from NOX2-deficient mice. Following Ang II incubation, endothelium-dependent vasodilation was mainly mediated by cytochrome P450 oxygenase (CYP450) metabolites, while the contribution of nitric oxide synthase (NOS) and 12/15-lipoxygenase (12/15-LOX) pathways became negligible. These findings provide evidence that Ang II induces endothelial dysfunction in mouse ophthalmic arteries via AT1R activation and NOX2-dependent ROS formation. From a clinical point of view, the blockade of AT1R signaling and/or NOX2 may be helpful to retain or restore endothelial function in ocular blood vessels in certain ocular diseases.

Cabergoline versus calcium infusion in the prevention of ovarian hyperstimulation syndrome: a randomised controlled study

The aim of this study was to compare the efficacy of calcium infusion versus cabergoline in the prevention of ovarian hyperstimulation syndrome (OHSS) in IVF patients at high risk for OHSS. One hundred and seventy patients who were stimulated using the long luteal GnRH agonist protocol and at high risk for developing OHSS were randomised in a 1:1 ratio to cabergoline group and calcium gluconate group. In cabergoline group, 0.5 mg of cabergoline was administered once daily p.o. for eight days starting on the day of HCG administration. In calcium gluconate group, intravenous calcium gluconate (10%, 10 ml in 200 ml of physiologic saline) was administered daily for four days starting on the day of ovum pickup. Six patients in cabergoline group and eight patients in calcium gluconate group developed moderate OHSS. One patient in each group developed severe OHSS. The incidence of moderate/severe OHSS was comparable between both groups (8.24% vs. 10.59%, p value  =  .599, OR = 0.76, 95% CI [0.269-2.138]). The implantation, clinical and ongoing pregnancy rates were similar in the two groups (16.91% vs. 15.84%, p = .771, 35.29% vs. 32.94%, p = .746, and 30.59% vs. 28.24%, p = .736, respectively). In conclusion, calcium infusion and cabergoline have comparable effectiveness in the prevention of OHSS. Both drugs are well tolerated, cheap and have no adverse effects on the reproductive outcomes of IVF cycle.Clinical trial registration: The trial was registered on clinical trials.gov database [NCT02875587].Impact StatementWhat is already known on this subject? The effectiveness of cabergoline in the prevention of OHSS in IVF patients at high risk for OHSS is confirmed by overwhelming scientific evidence. Calcium infusion is a novel strategy for prevention of OHSS. Few studies reported the use of calcium infusion in the prevention of OHSS. A retrospective study and a randomised controlled study revealed that calcium infusion reduces the incidence of OHSS. Moreover, a quasi-randomised study revealed that calcium infusion is as effective as cabergoline in the prevention of OHSS.What the results of this study add? Calcium infusion and cabergoline have comparable effectiveness in the prevention of OHSS. Both drugs are well tolerated, cheap and have no adverse effects on the reproductive outcomes of IVF cycle.What the implications are of these findings for clinical practice and/or further research? Calcium infusion should be used to minimise the incidence of OHSS in IVF patients at high risk for OHSS.

RAAS: A Convergent Player in Ischemic Heart Failure and Cancer

The current global prevalence of heart failure is estimated at 64.34 million cases, and it is expected to increase in the coming years, especially in countries with a medium-low sociodemographic index where the prevalence of risk factors is increasing alarmingly. Heart failure is associated with many comorbidities and among them, cancer has stood out as a contributor of death in these patients. This connection points out new challenges both in the context of the pathophysiological mechanisms involved, as well as in the quality of life of affected individuals. A hallmark of heart failure is chronic activation of the renin-angiotensin-aldosterone system, especially marked by a systemic increase in levels of angiotensin-II, a peptide with pleiotropic activities. Drugs that target the renin-angiotensin-aldosterone system have shown promising results both in the prevention of secondary cardiovascular events in myocardial infarction and heart failure, including a lower risk of certain cancers in these patients, as well as in current cancer therapies; therefore, understanding the mechanisms involved in this complex relationship will provide tools for a better diagnosis and treatment and to improve the prognosis and quality of life of people suffering from these two deadly diseases.

PPARγ Agonists: Emergent Therapy in Endometriosis

Endometriosis is one of the major gynecological diseases of reproductive-age women. This disease is characterized by the presence of glands and stroma outside the uterine cavity. Several studies have shown the major role of inflammation, angiogenesis, adhesion and invasion, and apoptosis in endometriotic lesions. Nevertheless, the mechanisms underlying endometriotic mechanisms still remain unclear and therapies are not currently efficient. The introduction of new agents can be effective by improving the condition of patients. PPARγ ligands can directly modulate these pathways in endometriosis. However, data in humans remain low. Thus, the purpose of this review is to summarize the potential actions of PPARγ agonists in endometriosis by acting on inflammation, angiogenesis, invasion, adhesion, and apoptosis.

Angioregulatory microRNAs in breast cancer: Molecular mechanistic basis and implications for therapeutic strategies

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Cancer-associated angiogenesis is a fundamental process in tumor growth and metastasis.

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Angioregulatory miRNA–target gene interaction is not only involved in sprouting vessels of breast tumors but also, trans-differentiation of breast cancer cells to endothelial cells in a process termed vasculogenic mimicry.

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Successful targeting of tumor angiogenesis is still a missing link in the treatment of Breast cancer (BC) due to the low effectiveness of anti-angiogenic therapies in this cancer.

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Response to anti-angiogenic therapeutics are controlled by a miRNAs, so the identification of interaction networks of miRNAs–targets can be applicable in determining anti-angiogeneic therapy and new biomarkers in BC.

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Angioregulatory miRNAs in breast cancer cells and their microenvironment have therapeutic potential in cancer treatment.

Background

Cancer-associated angiogenesis is a fundamental process in tumor growth and metastasis. A variety of signaling regulators and pathways contribute to establish neovascularization, among them as small endogenous non-coding RNAs, microRNAs (miRNAs) play prominent dual regulatory function in breast cancer (BC) angiogenesis.

Aim of Review

This review aims at describing the current state-of-the-art in BC angiogenesis-mediated by angioregulatory miRNAs, and an overview of miRNAs dysregulation association with the anti-angiogenic response in addition to potential clinical application of miRNAs-based therapeutics.

Key Scientific Concepts of Review

Angioregulatory miRNA–target gene interaction is not only involved in sprouting vessels of breast tumors but also, trans-differentiation of BC cells to endothelial cells (ECs) in a process termed vasculogenic mimicry. Using canonical and non-canonical angiogenesis pathways, the tumor cell employs the oncogenic characteristics such as miRNAs dysregulation to increase survival, proliferation, oxygen and nutrient supply, and treatment resistance. Angioregulatory miRNAs in BC cells and their microenvironment have therapeutic potential in cancer treatment. Although, miRNAs dysregulation can serve as tumor biomarker nevertheless, due to the association of miRNAs dysregulation with anti-angiogenic resistant phenotype, clinical benefits of anti-angiogenic therapy might be challenging in BC. Hence, unveiling the molecular mechanism underlying angioregulatory miRNAs sparked a booming interest in finding new treatment strategies such as miRNA-based therapies in BC.

Breast cancer and the renin-angiotensin system (RAS): Therapeutic approaches and related metabolic diseases

The Renin-Angiotensin System (RAS) is classically recognized for regulating blood pressure and fluid balance. Recently, this role has extended to other areas including inflammation, obesity, diabetes, as well as breast cancer. RAS components are expressed in normal and cancerous breast tissues, and downregulation of RAS inhibits metastasis, proliferation, angiogenesis, and desmoplasia in the tumor microenvironment. Therefore, RAS inhibitors (Angiotensin receptor blockers, ARBs, or angiotensin converting enzyme inhibitors, ACE-I) may be beneficial as preventive adjuvant therapies to thwart breast cancer development and improve outcomes, respectively. Given the beneficial effects of RAS inhibitors in metabolic diseases, which often co-exist in breast cancer patients, combining RAS inhibitors with other breast cancer therapies may enhance the effectiveness of current treatments. This review scrutinizes above associations, to advance our understanding of the role of RAS in breast cancer and its potential for repurposing of RAS inhibitors to improve the therapeutic approach for breast cancer patients.

CCL5 production by fibroblasts through a local renin-angiotensin system in malignant melanoma affects tumor immune responses

PURPOSE

To enhance the antitumor effects of anti-programmed death-1 (PD-1) antibodies, it is important to reverse cancer-induced immunosuppression. We previously reported that a localized renin-angiotensin system in the tumor microenvironment inhibited tumor immunity via macrophages. In this study, we analyzed the underlying mechanism through which fibroblasts express tumor immunity influenced by the angiotensin receptor.

METHODS

We used an angiotensin receptor inhibitor (ARB) to inhibit renin-angiotensin system. Furthermore, angiotensin receptors were knocked out from mice fibroblasts, which were then collected. The fibroblasts and a malignant melanoma were then transfused into a mouse model and tumor immunity response was analyzed.

RESULTS

Fibroblasts produced CC motif chemokine ligand 5 (CCL5) on renin-angiotensin system stimulation, and this production decreased after ARB administration. In mice with transplanted malignant melanoma, ARB administration resulted in decreased CCL5 concentration in the blood, increase in tumor-infiltrating T cells, decrease in regulatory T cells, as well as an increase in tumor antigen-specific T-cell responses. The mice in which the angiotensin receptor knockout fibroblasts and malignant melanoma were transplanted showed a similar decrease in CCL5 concentration and increased tumor antigen-specific T-cell responses. Furthermore, ARB and anti-PD-1 antibody were administered in combination, which resulted in significantly better tumor growth inhibition over monotherapy.

CONCLUSION

Inhibiting renin-angiotensin system restored the therapeutic efficacy of inhibited anti-PD-1 antibodies. Thus, this could be considered a valid approach to enhance the therapeutic efficacy of anti-PD-1 antibodies.

Renin-Angiotensin System in the Tumor Microenvironment

For enhancing the antitumor effects of current immunotherapies including immune-checkpoint blockade, it is important to reverse cancer-induced immunosuppression. The renin-angiotensin system (RAS) controls systemic body fluid circulation; however, the presence of a local RAS in tumors has been reported. Furthermore, the local RAS in tumors influences various immune and interstitial cells and affects tumor immune response. RAS stimulation through the angiotensin II type 1 receptor has been reported to inhibit tumor immune response. Therefore, RAS inhibitors and combined treatment with immunotherapy are expected in the future. In this chapter, we provide a background on the RAS and describe the tumor environment with regard to the RAS and tumor immune response.

A role for aldehyde dehydrogenase (ALDH) 2 in angiotensin II-mediated decrease in angiogenesis of coronary endothelial cells

Diabetes-induced coronary endothelial cell (CEC) dysfunction contributes to diabetic heart diseases. Angiotensin II (Ang II), a vasoactive hormone, is upregulated in diabetes, and is reported to increase oxidative stress in CECs. 4-hydroxy-2-nonenal (4HNE), a key lipid peroxidation product, causes cellular dysfunction by forming adducts with proteins. By detoxifying 4HNE, aldehyde dehydrogenase (ALDH) 2 reduces 4HNE mediated proteotoxicity and confers cytoprotection. Thus, we hypothesize that ALDH2 improves Ang II-mediated defective CEC angiogenesis by decreasing 4HNE-mediated cytotoxicity. To test our hypothesis, we treated the cultured mouse CECs (MCECs) with Ang II (0.1, 1 and 10 μM) for 2, 4 and 6 h. Next, we treated MCECs with Alda-1 (10 μM), an ALDH2 activator or disulfiram (2.5 μM)/ALDH2 siRNA (1.25 nM), the ALDH2 inhibitors, or blockers of angiotensin II type-1 and 2 receptors i.e. Losartan and PD0123319 respectively before challenging MCECs with 10 μM Ang II. We found that 10 μM Ang II decreased tube formation in MCECs with in vitro angiogenesis assay (P < .0005 vs control). 10 μM Ang II downregulated the levels of vascular endothelial growth factor receptor 1 (VEGFR1) (p < .005 for mRNA and P < .05 for protein) and VEGFR2 (p < .05 for mRNA and P < .005 for protein) as well as upregulated the levels of angiotensin II type-2 receptor (AT2R) (p < .05 for mRNA and P < .005 for protein) and 4HNE-adducts (P < .05 for protein) in cultured MCECs, compared to controls. ALDH2 inhibition with disulfiram/ALDH2 siRNA exacerbated 10 μM Ang II-induced decrease in coronary angiogenesis (P < .005) by decreasing the levels of VEGFR1 (P < .005 for mRNA and P < .05 for protein) and VEGFR2 (P < .05 for both mRNA and protein) and increasing the levels of AT2R (P < .05 for both mRNA and protein) and 4HNE-adducts (P < .05 for protein) relative to Ang II alone. AT2R inhibition per se improved angiogenesis in MCECs. Additionally, enhancing ALDH2 activity with Alda 1 rescued Ang II-induced decrease in angiogenesis by increasing the levels of VEGFR1, VEGFR2 and decreasing the levels of AT2R. In summary, ALDH2 can be an important target in reducing 4HNE-induced proteotoxicity and improving angiogenesis in MCECs. Finally, we conclude ALDH2 activation can be a therapeutic strategy to improve coronary angiogenesis to ameliorate cardiometabolic diseases.

Cognitive impact of COVID-19: looking beyond the short term

COVID-19 is primarily a respiratory disease but up to two thirds of hospitalised patients show evidence of central nervous system (CNS) damage, predominantly ischaemic, in some cases haemorrhagic and occasionally encephalitic. It is unclear how much of the ischaemic damage is mediated by direct or inflammatory effects of virus on the CNS vasculature and how much is secondary to extracranial cardiorespiratory disease. Limited data suggest that the causative SARS-CoV-2 virus may enter the CNS via the nasal mucosa and olfactory fibres, or by haematogenous spread, and is capable of infecting endothelial cells, pericytes and probably neurons. Extracranially, SARS-CoV-2 targets endothelial cells and pericytes, causing endothelial cell dysfunction, vascular leakage and immune activation, sometimes leading to disseminated intravascular coagulation. It remains to be confirmed whether endothelial cells and pericytes in the cerebral vasculature are similarly targeted. Several aspects of COVID-19 are likely to impact on cognition. Cerebral white matter is particularly vulnerable to ischaemic damage in COVID-19 and is also critically important for cognitive function. There is accumulating evidence that cerebral hypoperfusion accelerates amyloid-β (Aβ) accumulation and is linked to tau and TDP-43 pathology, and by inducing phosphorylation of α-synuclein at serine-129, ischaemia may also increase the risk of development of Lewy body disease. Current therapies for COVID-19 are understandably focused on supporting respiratory function, preventing thrombosis and reducing immune activation. Since angiotensin-converting enzyme (ACE)-2 is a receptor for SARS-CoV-2, and ACE inhibitors and angiotensin receptor blockers are predicted to increase ACE-2 expression, it was initially feared that their use might exacerbate COVID-19. Recent meta-analyses have instead suggested that these medications are protective. This is perhaps because SARS-CoV-2 entry may deplete ACE-2, tipping the balance towards angiotensin II-ACE-1-mediated classical RAS activation: exacerbating hypoperfusion and promoting inflammation. It may be relevant that APOE ε4 individuals, who seem to be at increased risk of COVID-19, also have lowest ACE-2 activity. COVID-19 is likely to leave an unexpected legacy of long-term neurological complications in a significant number of survivors. Cognitive follow-up of COVID-19 patients will be important, especially in patients who develop cerebrovascular and neurological complications during the acute illness.

Rho kinase inhibitor fasudil reduces l-DOPA-induced dyskinesia in a rat model of Parkinson's disease

BACKGROUND AND PURPOSE

Rho kinase (ROCK) activation is involved in neuroinflammatory processes leading to progression of neurodegenerative diseases such as Parkinson's disease. Furthermore, ROCK plays a major role in angiogenesis. Neuroinflammation and angiogenesis are mechanisms involved in developing l-DOPA-induced dyskinesias (LID). However, it is not known whether ROCK plays a role in LID and whether ROCK inhibitors may be useful against LID.

EXPERIMENTAL APPROACH

In rats, we performed short- and long-term dopaminergic lesions using 6-hydroxydopamine and developed a LID model. Effects of dopaminergic lesions and LID on the RhoA/ROCK levels were studied by western blot, real-time PCR analyses and ROCK activity assays in the substantia nigra and striatum. The effects of the ROCK inhibitor fasudil on LID were particularly investigated.

KEY RESULTS

Short-term 6-hydroxydopamine lesions increased nigrostriatal RhoA/ROCK expression, apparently related to the active neuroinflammatory process. However, long-term dopaminergic denervation (completed and stabilized lesions) led to a decrease in RhoA/ROCK levels. Rats with LID showed a significant increase of RhoA and ROCK expression. The development of LID was reduced by the ROCK inhibitor fasudil (10 and 40 mg·kg^-1 ), without interfering with the therapeutic effect of l-DOPA. Interestingly, treatment of 40 mg·kg^-1 of fasudil also induced a significant reduction of dyskinesia in rats with previously established LID.

CONCLUSION AND IMPLICATIONS

The present results suggest that ROCK is involved in the pathophysiology of LID and that ROCK inhibitors such as fasudil may be a novel target for preventing or treating LID. Furthermore, previous studies have revealed neuroprotective effects of ROCK inhibitors.

Immunomodulatory effects of renin-angiotensin system inhibitors on T lymphocytes in mice with colorectal liver metastases

BACKGROUND

It is now recognized that many anticancer treatments positively modulate the antitumor immune response. Clinical and experimental studies have shown that inhibitors of the classical renin-angiotensin system (RAS) reduce tumor progression and are associated with better outcomes in patients with colorectal cancer. RAS components are expressed by most immune cells and adult hematopoietic cells, thus are potential targets for modulating tumor-infiltrating immune cells and can provide a mechanism of tumor control by the renin-angiotensin system inhibitors (RASi).

AIM

To investigate the effects of the RASi captopril on tumor T lymphocyte distribution in a mouse model of colorectal liver metastases.

METHODS

Liver metastases were established in a mouse model using an autologous colorectal cancer cell line. RASi (captopril 750 mg/kg) or carrier (saline) was administered to the mice daily via intraperitoneal injection, from day 1 post-tumor induction to endpoint (day 15 or 21 post-tumor induction). At the endpoint, tumor growth was determined, and lymphocyte infiltration and composition in the tumor and liver tissues were analyzed by flow cytometry and immunohistochemistry (IHC).

RESULTS

Captopril significantly decreased tumor viability and impaired metastatic growth. Analysis of infiltrating T cells into liver parenchyma and tumor tissues by IHC and flow cytometry showed that captopril significantly increased the infiltration of CD3+ T cells into both tissues at day 15 following tumor induction. Phenotypical analysis of CD45+ CD3+ T cells indicated that the major contributing phenotype to this influx is a CD4 and CD8 double-negative T cell (DNT) subtype, while CD4+ T cells decreased and CD8+ T cells remained unchanged. Captopril treatment also increased the expression of checkpoint receptor PD-1 on CD8+and DNT subsets .

CONCLUSION

Captopril treatment modulates the immune response by increasing the infiltration and altering the phenotypical composition of T lymphocytes and may be a contributing mechanism for tumor control.

Chinese Medicine She-Xiang-Xin-Tong-Ning, Containing Moschus, Corydalis and Ginseng, Protects from Myocardial Ischemia Injury via Angiogenesis

The Chinese patent medicine She-Xiang-Xin-Tong-Ning (SXXTN) is a clinical medication for coronary heart disease (CHD) and angina pectoris. This study aimed to investigate pharmacological effects of SXXTN and elucidate the role in angiogenesis on human umbilical vein endothelial cells (HUVECs) and acute myocardial ischemia (AMI) rats. We prepared SXXTN to treat the cells to reveal their effects on oxidative stress-damaged cell viability, as well as cell proliferation, migration, and tube formation processes. SXXTN was also used to treat coronary artery ligation-induced acute myocardial ischemia rats to confirm whether it had positive effect on myocardial issues by hematoxylin and eosin (HE), 2,3,5-triphenyltetrazolium chloride (TTC) staining and immunohistochemical staining. We measured the levels of peroxidative damage-related enzymes in cytoplasm and serum by biochemical kits and detected vascular endothelial growth factor (VEGF), angiotensin II (Ang II), thromboxane B2 (TXB2), and 6-keto-prostaglandin F1 alpha (6-keto-PGF1[Formula: see text]) levels in cells and rats by enzyme-linked immunosorbent assay (ELISA) kits. The results showed that SXXTN protects HUVECs against oxidative stress damage and reversed the decrease of superoxide dismutase (SOD), glutathione (GSH) and increase of creatine kinase (CK), lactate dehydrogenase (LDH) caused by oxidative stress. SXXTN promoted angiogenesis through stimulating cell migration, tube formation, and activating VEGF/VEGFR2 and ERK1/2 pathways. Furthermore, SXXTN reduced infarct size and inhibited PGI2/TXA2 imbalance, preventing atherosclerosis plaque rupture leading to worsening coronary heart disease. Taken together, we report the first in vivo and in vitro evidence that SXXTN reduced oxidative stress-mediated damage and enhanced angiogenesis, which might be useful in treatment of myocardial infarction.

Analysis of key candidate genes and pathways of endometriosis pathophysiology by a genomics-bioinformatics approach

Endometriosis is a common disease in women, but the signaling pathways and driven genes involved remain unclear. This study integrated four datasets to elucidate potential key candidate genes and pathways in endometriosis. Four expression profile datasets including 29 endometriosis lesions and 37 normal tissues were integrated and analyzed. Differentially expressed genes (DEGs) were sorted, and the gene ontology, pathway enrichment, and protein-protein interaction network of candidate genes were then analyzed. A total of 94 shared DEGs were identified from the four datasets. The DEGs were clustered based on functions and signaling pathways through the analysis of significant enrichment. Among the DEG protein-protein interaction network complex, 87 nodes/DEGs were identified. Furthermore, 18 central node genes were identified, and most of the corresponding genes were involved in the angiotensin system, smooth muscle contraction, cell junction organization, and lipoxin pathways. Through integrated bioinformatic analysis, we identified candidate genes and pathways in endometriosis, which could improve our understanding of endometriosis.

cAMP guided his way: a life for G protein-mediated signal transduction and molecular pharmacology-tribute to Karl H. Jakobs

Karl H. Jakobs, former editor-in-chief of Naunyn-Schmiedeberg's Archives of Pharmacology and renowned molecular pharmacologist, passed away in April 2018. In this article, his scientific achievements regarding G protein-mediated signal transduction and regulation of canonical pathways are summarized. Particularly, the discovery of inhibitory G proteins for adenylyl cyclase, methods for the analysis of receptor-G protein interactions, GTP supply by nucleoside diphosphate kinases, mechanisms in phospholipase C and phospholipase D activity regulation, as well as the development of the concept of sphingosine-1-phosphate as extra- and intracellular messenger will presented. His seminal scientific and methodological contributions are put in a general and timely perspective to display and honor his outstanding input to the current knowledge in molecular pharmacology.

Inflammation leads through PGE/EP3 signaling to HDAC5/MEF2-dependent transcription in cardiac myocytes

The myocyte enhancer factor 2 (MEF2) regulates transcription in cardiac myocytes and adverse remodeling of adult hearts. Activators of G protein-coupled receptors (GPCRs) have been reported to activate MEF2, but a comprehensive analysis of GPCR activators that regulate MEF2 has to our knowledge not been performed. Here, we tested several GPCR agonists regarding their ability to activate a MEF2 reporter in neonatal rat ventricular myocytes. The inflammatory mediator prostaglandin E₂ (PGE₂) strongly activated MEF2. Using pharmacological and protein-based inhibitors, we demonstrated that PGE₂ regulates MEF2 via the EP₃ receptor, the βγ subunit of G_i/o protein and two concomitantly activated downstream pathways. The first consists of Tiam1, Rac1, and its effector p21-activated kinase 2, the second of protein kinase D. Both pathways converge on and inactivate histone deacetylase 5 (HDAC5) and thereby de-repress MEF2. In vivo, endotoxemia in MEF2-reporter mice induced upregulation of PGE₂ and MEF2 activation. Our findings provide an unexpected new link between inflammation and cardiac remodeling by de-repression of MEF2 through HDAC5 inactivation, which has potential implications for new strategies to treat inflammatory cardiomyopathies.

Rho-Associated Coiled-Coil Kinase (ROCK) in Molecular Regulation of Angiogenesis

Identified as a major downstream effector of the small GTPase RhoA, Rho-associated coiled-coil kinase (ROCK) is a versatile regulator of multiple cellular processes. Angiogenesis, the process of generating new capillaries from the pre-existing ones, is required for the development of various diseases such as cancer, diabetes and rheumatoid arthritis. Recently, ROCK has attracted attention for its crucial role in angiogenesis, making it a promising target for new therapeutic approaches. In this review, we summarize recent advances in understanding the role of ROCK signaling in regulating the permeability, migration, proliferation and tubulogenesis of endothelial cells (ECs), as well as its functions in non-ECs which constitute the pro-angiogenic microenvironment. The therapeutic potential of ROCK inhibitors in angiogenesis-related diseases is also discussed.

Angiotensin II Attenuates the Bioactivities of Human Endothelial Progenitor Cells via Downregulation of β2-Adrenergic Receptor

Cross talks between the renin-angiotensin system (RAS), sympathetic nervous system, and vascular homeostasis are tightly coordinated in hypertension. Angiotensin II (Ang II), a key factor in RAS, when abnormally activated, affects the number and bioactivity of circulating human endothelial progenitor cells (hEPCs) in hypertensive patients. In this study, we investigated how the augmentation of Ang II regulates adrenergic receptor-mediated signaling and angiogenic bioactivities of hEPCs. Interestingly, the short-term treatment of hEPCs with Ang II drastically attenuated the expression of beta-2 adrenergic receptor (ADRB2), but did not alter the expression of beta-1 adrenergic receptor (ADRB1) and Ang II type 1 receptor (AT1R). EPC functional assay clearly demonstrated that the treatment with ADRB2 agonists significantly increased EPC bioactivities including cell proliferation, migration, and tube formation abilities. However, EPC bioactivities were decreased dramatically when treated with Ang II. Importantly, the attenuation of EPC bioactivities by Ang II was restored by treatment with an AT1R antagonist (telmisartan; TERT). We found that AT1R binds to ADRB2 in physiological conditions, but this binding is significantly decreased in the presence of Ang II. Furthermore, TERT, an Ang II-AT1R interaction blocker, restored the interaction between AT1R and ADRB2, suggesting that Ang II might induce the dysfunction of EPCs via downregulation of ADRB2, and an AT1R blocker could prevent Ang II-mediated ADRB2 depletion in EPCs. Taken together, our report provides novel insights into potential therapeutic approaches for hypertension-related cardiovascular diseases.

Renin-angiotensin inhibitors reprogram tumor immune microenvironment: A comprehensive view of the influences on anti-tumor immunity

Renin-angiotensin system inhibitors (RASi) have shown potential anti-tumor effects that may have a significant impact in cancer therapy. The components of the renin-angiotensin system (RAS) including both, conventional and alternative axis, appear to have contradictory effects on tumor biology. The mechanisms by which RASi impair tumor growth extend beyond their function of modulating tumor vasculature. The major focus of this review is to analyze other mechanisms by which RASi reprogram the tumor immune microenvironment. These involve impairing hypoxia and acidosis within the tumor stroma, regulating inflammatory signaling pathways and oxidative stress, modulating the function of the non-cellular components and immune cells, and regulating the cross-talk between kalli krein kinin system and RAS.

Early increase in blood supply (EIBS) is associated with tumor risk in the Azoxymethane model of colon cancer

Background

The present study aimed to investigate the role of blood supply in early tumorigenesis in colorectal cancer. We leveraged the renin angiotensin system (RAS) to alter colonic blood supply and determine the effect on tumor initiation and progression.

Methods

To test the effect of blood supply on tumorigenesis, 53 male A/J mice were randomly assigned to one of three RAS modulation groups and one of two AOM treatments. The RAS modulation groups were I) water (RAS-unmodulated) as a control group, II) angiotensin-II and III) the angiotensin receptor blocker, Losartan. The mice in each group were then randomly split into either the saline control condition or the AOM-treated condition in which tumors were induced with a standard protocol of serial azoxymethane (AOM) injections. To monitor microvascular changes in the rectal mucosa during the study, we used confocal laser endomicroscopy (CLE) with FITC-Dextran for in-vivo imaging of vessels and polarization-gated spectroscopy (PGS) to quantify rectal hemoglobin concentration ([Hb]) and blood vessel radius (BVR).

Results

At 12 weeks post-AOM injections and before tumor formation, CLE images revealed many traditional hallmarks of angiogenesis including vessel dilation, loss of co-planarity, irregularity, and vessel sprouting in the pericryptal capillaries of the rectal mucosa in AOM-Water tumor bearing mice. PGS measurements at the same time-point showed increased rectal [Hb] and decreased BVR. At later time points, CLE images showed pronounced angiogenic features including irregular networks throughout the colon. Notably, the AOM-Losartan mice had significantly lower tumor multiplicity and did not exhibit the same angiogenic features observed with CLE, or the increase in [Hb] or decrease in BVR measured with PGS. The AOM-AngII mice did not have any significant trends.

Conclusion

In-vivo PGS measurements of rectal colonic blood supply as well as CLE imaging revealed angiogenic disruptions to the capillary network prior to tumor formation. Losartan demonstrated an effective way to mitigate the changes to blood supply during tumorigenesis and reduce tumor multiplicity. These effects can be used in future studies to understand the early vessel changes observed.

Catecholamines facilitate VEGF-dependent angiogenesis via β2-adrenoceptor-induced Epac1 and PKA activation

Chronic stress has been associated with the progression of cancer and antagonists for β-adrenoceptors (βAR) are regarded as therapeutic option. As they are also used to treat hemangiomas as well as retinopathy of prematurity, a role of endothelial β₂AR in angiogenesis can be envisioned. We therefore investigated the role of β₂AR-induced cAMP formation by analyzing the role of the cAMP effector molecules exchange factor directly activated by cAMP 1 (Epac1) and protein kinase A (PKA) in endothelial cells (EC). Epac1-deficient mice showed a reduced amount of pre-retinal neovascularizations in the model of oxygen-induced retinopathy, which is predominantly driven by vascular endothelial growth factor (VEGF). siRNA-mediated knockdown of Epac1 in human umbilical vein EC (HUVEC) decreased angiogenic sprouting by lowering the expression of the endothelial VEGF-receptor-2 (VEGFR-2). Conversely, Epac1 activation by β₂AR stimulation or the Epac-selective activator cAMP analog 8-p-CPT-2’-O-Me-cAMP (8-pCPT) increased VEGFR-2 levels and VEGF-dependent sprouting. Similar to Epac1 knockdown, depletion of the monomeric GTPase Rac1 decreased VEGFR-2 expression. As Epac1 stimulation induces Rac1 activation, Epac1 might regulate VEGFR-2 expression through Rac1. In addition, we found that PKA was also involved in the regulation of angiogenesis in EC since the adenylyl cyclase (AC) activator forskolin (Fsk), but not 8-pCPT, increased sprouting in Epac1-depleted HUVEC and this increase was sensitive to a selective synthetic peptide PKA inhibitor. In accordance, β₂AR- and AC-activation, but not Epac1 stimulation increased VEGF secretion in HUVEC.

Our data indicate that high levels of catecholamines, which occur during chronic stress, prime the endothelium for angiogenesis through a β₂AR-mediated increase in endothelial VEGFR-2 expression and VEGF secretion.

Renal cell carcinoma: new insights and challenges for a clinician scientist

There is a growing recognition of the complex interplay between renal cell cancer (RCC), kidney function, mechanical reduction of nephron mass, and systemic agents targeting the cancer. Earlier detection of RCC and rising life expectancy of cancer survivors places a greater emphasis on preservation of renal function after cancer resection and during systemic therapy. Unique adverse effects associated with RCC drugs not only help reveal cancer pathophysiology but also expand our knowledge of normal cell signaling and metabolism. In this review, we outline our current understanding of RCC biology and treatment, their bidirectional relationship with kidney function, and unmet research needs in this field.

Combination therapy with telmisartan and parecoxib induces regression of endometriotic lesions

BACKGROUND AND PURPOSE

Telmisartan suppresses the development of endometriotic lesions. However, the drug also up-regulates the expression of COX-2, which has been suggested to promote the progression of endometriosis. Accordingly, in the present study we analysed whether a combination therapy with telmisartan and a COX-2 inhibitor may be more effective in the treatment of endometriotic lesions than the application of telmisartan alone.

EXPERIMENTAL APPROACH

Endometriotic lesions were induced in the peritoneal cavity of C57BL/6 mice, which were treated daily with an i.p. injection of telmisartan (10 mg·kg^-1 ), parecoxib (5 mg·kg^-1 ), a combination of telmisartan and parecoxib or vehicle. Therapeutic effects on lesion survival, growth, vascularization, innervation and protein expression were studied over 4 weeks by high-resolution ultrasound imaging as well as immunohistochemical and Western blot analyses.

KEY RESULTS

Telmisartan-treated lesions exhibited a significantly reduced lesion volume when compared with vehicle-treated controls and parecoxib-treated lesions. This inhibitory effect of telmisartan was even more pronounced when it was used in combination with parecoxib. The combination therapy resulted in a reduced microvessel density as well as lower numbers of proliferating Ki67-positive cells and higher numbers of apoptotic cleaved caspase-3-positive stromal cells within the lesions. This was associated with a lower expression of COX-2, MMP-9 and p-Akt/Akt when compared with controls. The application of the two drugs further inhibited the ingrowth of nerve fibres into the lesions.

CONCLUSIONS AND IMPLICATIONS

Combination therapy with telmisartan and a COX-2 inhibitor represents a novel, effective pharmacological strategy for the treatment of endometriosis.

A precision-guided MWNT mediated reawakening the sunk synergy in RAS for anti-angiogenesis lung cancer therapy

Multi-walled carbon nanotube (MWNT) with its versatility has exhibited tremendous superiority in drug delivery. Despite plenty of researches on MWNT based delivery systems, precision-guided assistances to maximize their profitable properties are still lacking in substantive progress. We developed here a dual-targeting and co-delivery system based on MWNT for antiangiogenesis therapy in lung cancer which aimed at renin-angiotensin system (RAS) dysregulation by synergistically conducting angiotensin II type 1 receptor (AT₁R) and type 2 receptor (AT₂R) pathway. In this work, iRGD peptide connected to polyethyleneimine (PEI) was linked to MWNT skeleton, accompanying with candesartan (CD) conjugated to MWNT mediated by cystamine (SS). The functionalized MWNT is assembled with plasmid AT₂ (pAT₂) to form iRGD-PEI-MWNT-SS-CD/pAT₂ complexes. iRGD and CD act as pilots for complexes to dually target symbolic ανβ3-integrin and AT₁R both overexpressed on tumor angiogenic endothelium and lung cancer cell. CD as chemotherapy showed synergistic downregulation of VEGF when combining of pAT₂ and efficiently inhibited angiogenesis. iRGD-PEI-MWNT-SS-CD/pAT₂ complexes greatly appreciated drug activities by changing drug distribution and exhibited remarkable tumor growth suppression in A549 xenograft nude mice. Our work presents that such dual-targeting strategy highly improves the delivery performance of MWNT and open a new avenue for RAS related lung cancer therapy.

Role of agonistic autoantibodies against type-1 angiotensin II receptor in the pathogenesis of retinopathy in preeclampsia

To investigate the mechanism underlying AT1-AA-induced retinopathy in severe preeclampsia by measuring the positive rate and titer of AT1-AA in plasma from women with severe preeclampsia and normal pregnant women to see whether AT1-AA titer was correlated with the grade of retinopathy. A preeclampsia rat model was also established by intravenous injection of AT1-AA extracted from the plasma of patient suffering from severe preeclampsia. The results showed that the plasma titer and positive rate of AT1-AA were significantly higher in women with severe preeclampsia than normal pregnant women. The antibody titer in cases of severe preeclampsia was associated with the grade of retinopathy, and positively correlated with the level of TNF-α and VEGF. The animal experiment results showed that the modeled rats presented symptoms very similar to symptoms of human preeclampsia, including retinopathy. Ocular fundus examination showed retinal microvascular abnormalities, hemorrhaging and leakage in the severe preeclampsia. Morphological changes included edema, thickening of the INL and ONL, and pigment atrophy. TNF-α and VEGF levels were increased in the vitreous humor and retina of the model rats. Our studies results suggest that abnormal expression of AT1-AA could induce damage to retinal capillary endothelial cells and increase vascular permeability, resulting in retinopathy.

Renin-angiotensin system as a potential therapeutic target in stroke and retinopathy: experimental and clinical evidence

As our knowledge expands, it is now clear that the renin-angiotensin (Ang) system (RAS) mediates functions other than regulating blood pressure (BP). The RAS plays a central role in the pathophysiology of different neurovascular unit disorders including stroke and retinopathy. Moreover, the beneficial actions of RAS modulation in brain and retina have been documented in experimental research, but not yet exploited clinically. The RAS is a complex system with distinct yet interconnected components. Understanding the different RAS components and their functions under brain and retinal pathological conditions is crucial to reap their benefits. The aim of the present review is to provide an experimental and clinical update on the role of RAS in the pathophysiology and treatment of stroke and retinopathy. Combining the evidence from both these disorders allows a unique opportunity to move both fields forward.

Angiotensin II type 1 receptor antagonists in animal models of vascular, cardiac, metabolic and renal disease

We have reviewed the effects of angiotensin II type 1 receptor antagonists (ARBs) in various animal models of hypertension, atherosclerosis, cardiac function, hypertrophy and fibrosis, glucose and lipid metabolism, and renal function and morphology. Those of azilsartan and telmisartan have been included comprehensively whereas those of other ARBs have been included systematically but without intention of completeness. ARBs as a class lower blood pressure in established hypertension and prevent hypertension development in all applicable animal models except those with a markedly suppressed renin-angiotensin system; blood pressure lowering even persists for a considerable time after discontinuation of treatment. This translates into a reduced mortality, particularly in models exhibiting marked hypertension. The retrieved data on vascular, cardiac and renal function and morphology as well as on glucose and lipid metabolism are discussed to address three main questions: 1. Can ARB effects on blood vessels, heart, kidney and metabolic function be explained by blood pressure lowering alone or are they additionally directly related to blockade of the renin-angiotensin system? 2. Are they shared by other inhibitors of the renin-angiotensin system, e.g. angiotensin converting enzyme inhibitors? 3. Are some effects specific for one or more compounds within the ARB class? Taken together these data profile ARBs as a drug class with unique properties that have beneficial effects far beyond those on blood pressure reduction and, in some cases distinct from those of angiotensin converting enzyme inhibitors. The clinical relevance of angiotensin receptor-independent effects of some ARBs remains to be determined.

Angiotensin system inhibitors and survival in patients with metastatic renal cell carcinoma treated with VEGF-targeted therapy: A pooled secondary analysis of clinical trials

Use of angiotensin system inhibitors (ASIs; angiotensin receptor blockers or angiotensin-converting enzyme inhibitors) has been reported to be associated with improved survival in metastatic renal cell carcinoma (mRCC), particularly when used with vascular endothelial growth factor-targeted therapies. This study was a secondary pooled analysis of two Phase III randomized controlled trials (RCTs) of patients with mRCC: NCT00334282 comparing pazopanib to placebo and NCT00720941 comparing pazopanib to sunitinib. ASI users were defined as patients using an ASI at baseline. Association with overall survival (OS; primary outcome) and progression-free survival (PFS) was evaluated using Cox proportional hazards regression. The association was adjusted in multivariable analysis for baseline systolic blood pressure (SBP), use of other antihypertensive drugs and prognostic factors comprising the Heng risk criteria for mRCC. Of 1,545 patients pooled from the two RCTs, 649 (42%) were using one or more antihypertensive drugs at baseline, 385 (59%) of which were using an ASI. In the multivariable analysis of patients using pazopanib or sunitinib, no significant association was observed between baseline ASI use and OS (hazard ratio [HR] 0.97 [95% confidence interval (CI) 0.80-1.18], p = 0.80) or PFS (HR 0.88 [95% CI 0.73-1.06], p = 0.17). Exploratory subgroup analysis of NCT00720941 highlighted that the effect of baseline ASI use on OS may differ between patients treated with sunitinib and pazopanib. In conclusion, use of ASIs at baseline was not a significant independent prognostic factor for improved survival in a pooled analysis of mRCC patients treated with pazopanib or sunitinib.

Age-Related Macular Degeneration and Intracrine Biology: An Hypothesis

This laboratory has studied the intracellular actions of angiotensin II and other signaling proteins that can act in the intracellular space-peptides/proteins we have called intracrines. Moreover, we have suggested that general principles of intracrine action exist and can help explain the progression of some chronic degenerative diseases such as diabetic nephropathy and congestive heart failure. Here, a similar analysis is carried out in the case of age-related macular degeneration. We propose that intracrine mechanisms are operative in this disorder. In particular, we hypothesize that intracrine loops involving renin, angiotensin II, transforming growth factor-beta, vascular endothelial growth factor, bone morphogenetic protein-4, and p53, among other factors, are involved. If this analysis is correct, it suggests a commonality of mechanism linking chronic progressive renal diseases, congestive heart failure, and macular degeneration.

[Angiotensin converting enzyme: the antigenic properties of the domain, role in Alzheimer's disease and tumor progression]

Angiotensin converting enzyme (ACE, EC 3.4.15.1) was discovered and characterized in the Laboratory of biochemistry and chemical pathology of proteins under the direction of academician V.N. Orekhovich, where its physiological function, associated with a key role in the regulation of the renin-angiotensin (RAS) and the kallikrein-kinin systems that control blood flow in the body and homeostasis was first deciphered. We carried out a search for structural differences between the two highly homologous domains (N- and C-domains) of somatic ACE (sACE); it was based on a comparative analysis of antigenic determinants (or B-epitopes) of both domains. The revealed epitopes were classified with variable and conserved regions and functionally important sites of the molecule ACE. Essential difference was demonstrated between locations of the epitopes in the N- and C-domains. These data indicate the existence of structural differences between the domains of sACE. We studied the role of the domains of ACE in the metabolism of human amyloid beta peptide (Ab) - the main component of senile plaques, found in the brains of patients with Alzheimer's disease (AD). Our results demonstrated that only N-domain ACE cleaved the Ab between residues R5-H6, while, the C-domain of ACE failed to hydrolyze this region. In addition, the effect of post-translational modifications of Ab on its hydrolysis by the ACE was investigated. We show that isomerization of residue D7, a common non-enzymatic age-related modification found in AD-associated species, does not reduce the affinity of the peptide to the N-domain of ACE, and conversely, it increases. According to our data, the role of ACE in the metabolism of Ab becomes more significant in the development of AD. RAS is involved in malignant transformation and tumor progression. RAS components, including ACE and angiotensin II receptors type 1 (AT1R) are expressed in various human tumors. We found a significant increase in the level of ACE activity in the tumor tissue of squamous cell carcinoma of the cervix. In our viewpoint, the increase in ACE activity may be a marker of poor clinical prognosis.

Impact of renin-angiotensin system blockade on clinical outcome in glioblastoma

BACKGROUND AND PURPOSE

Despite surgery, radiotherapy (RT) and temozolomide (TMZ), the prognosis of glioblastoma (GBM) patients remains dismal. Normally prescribed with the aim to lower blood pressure, angiotensin-II (Ang-II) inhibitors were reported to reduce angiogenesis and tumour growth in several tumour models including one glioma. Thus whether treatment with Ang-II inhibitors could be associated with a better clinical outcome in GBM patients was investigated.

METHODS

A series of 81 consecutive patients, homogeneously treated with RT and TMZ for a newly diagnosed, supratentorial GBM, were analysed. The objective of this retrospective study was to assess the impact of angiotensin-converting enzyme inhibitors (ACEIs) and Ang-II receptor 1 blockers (ARBs) on functional independence, progression-free survival (PFS) and overall survival (OS).

RESULTS

Amongst the 81 GBM patients analysed, 26 were already treated for high blood pressure (seven with ACEIs and 19 with ARBs). The number of patients who remained functionally independent at 6 months after RT was higher in the group of patients treated with Ang-II inhibitors compared to the other patients (85% vs. 56%, P = 0.01). In patients treated with Ang-II inhibitors, PFS was 8.7 months (vs. 7.2 months in the other patients) and OS was 16.7 months (vs. 12.9 months). The use of Ang-II inhibitors was a significant prognostic factor for both PFS (P = 0.04) and OS (P = 0.04) in multivariate analysis.

CONCLUSION

Treatment with Ang-II inhibitors in combination with RT and TMZ might improve clinical outcome in GBMs. Prospective trials are needed to test this hypothesis.

Rho/MRTF-A-Induced Integrin Expression Regulates Angiogenesis in Differentiated Multipotent Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are known to undergo endothelial differentiation in response to treatment with vascular endothelial growth factor (VEGF), but their angiogenic ability is poorly characterized. In the present study, we aimed to further investigate the role of Rho/MRTF-A in angiogenesis by MSCs and the effect of the Rho/MRTF-A pathway on the expression of integrins α1β1 and α5β1, which are known to mediate physiological and pathological angiogenesis. Our results showed that increased expression of α1, α5, and β1 was observed during angiogenesis of differentiated MSCs, and the Rho/MRTF-A signaling pathway was demonstrated to be involved in regulating the expression of integrins α1, α5, and β1. Luciferase reporter assay and ChIP assay determined that MRTF-A could bind to and transactivate the integrin α1 and α5 promoters. Treatment with the Rho inhibitor C3 transferase, the Rho-associated protein kinase (ROCK) inhibitor Y27632 or with shMRTF-A inhibited both the upregulation of α1, α5, and β1 as well as angiogenesis. Furthermore, in human umbilical vein endothelial cells (HUVECs), MRTF-A deletion led to marked reductions in cell migration and vessel network formation compared with the control. These data demonstrate that Rho/MRTF-A signaling is an important mediator that controls integrin gene expression during MSC-mediated angiogenic processes.

Synergistic effect of angiotensin II on vascular endothelial growth factor-A-mediated differentiation of bone marrow-derived mesenchymal stem cells into endothelial cells

INTRODUCTION

Increased levels of angiotensin II (Ang II) and activity of Ang II receptor type 1 (AT1R) elicit detrimental effects in cardiovascular disease. However, the role of Ang II receptor type 2 (AT2R) remains poorly defined. Mesenchymal stem cells (MSCs) replenish and repair endothelial cells in the cardiovascular system. Herein, we investigated a novel role of angiotensin signaling in enhancing vascular endothelial growth factor (VEGF)-A-mediated differentiation of MSCs into endothelial cells (ECs).

METHODS

Bone marrow was aspirated from the femurs of Yucatan microswine. MSCs were extracted via ficoll density centrifugation technique and were strongly immunopositive for MSC markers, CD44, CD90, and CD105, but negative for hematopoietic markers, CD14 and CD45. Subsequently, naïve MSCs were differentiated for 10 days in varying concentrations and combinations of VEGF-A, Ang II, and AT1R or AT2R antagonists. Markers specific to ECs were determined by FACS analysis.

RESULTS

AT1R and AT2R expression and cellular localization was demonstrated in MSCs stimulated with VEGF-A and Ang II via quantitative RT-PCR and immunofluorescence, respectively. Differentiation of naïve MSCs in media containing Ang II (2 ng/ml) plus low-dose VEGF-A (2 ng/ml) produced a significantly higher percentage of cells that were positive for expression of EC markers (for example, platelet endothelial cell adhesion molecule, vascular endothelial Cadherin and von Willebrand factor) compared to VEGF-A alone. Ang II alone failed to induce EC marker expression. MSCs differentiated with the combination of Ang II and VEGF-A were capable of forming capillary tubes using an in vitro angiogenesis assay. Induction of EC marker expression was greatly attenuated by co-treatment of Ang II/VEGF-A with the AT2R antagonist PD123319, but not the AT1R antagonist telmisartan.

CONCLUSIONS

We report the presence of functional AT2R receptor on porcine bone marrow-derived MSCs, where it positively regulates EC differentiation. These findings have significant implications toward therapeutic approaches based on activation of AT2R, which could be a means to stimulate regeneration of damaged endothelium and prevent vascular thrombosis.

[Matrix metalloproteinases 2 and 9, their endogenous regulators, and angiotensin-converting enzyme in cervical squamous cell carcinoma]

OBJECTIVE

to investigate the specific features of the expression of matrix metalloproteinases 2 and 9 (MMP-2, MMP-9), tissue inhibitor of metalloptoteinase 2 (TIMP-2), urokinase-type plasminogen activator (uPA), and angiotensin-converting enzyme (ACE) in cervical squamous cell carcinoma (CSCC).

MATERIAL AND METHODS

The samples of tumor tissue and morphologically normal tissue adjacent to the tumor were investigated. Enzymatic assays applying specific substrates, as well as zymographic and immunohistochemical studies were used.

RESULTS

The invasive potential of CSCC has been established to be substantially influenced by the increased expression of MMP-9 and uPA and by the decreased expression of TIMP-2, as well as to a lesser extent by a change in MMP-2 expression. MMP-9 may serve as a marker for invasive growth. Enhanced ACE activity in cancer confirms the involvement of this enzyme in tumor progression. The morphologically normal tissue adjacent to the tumor shows the substantial expression of MMP-2 and MMP-9 and in some cases the enhanced activity of uPA and ACE, which makes an additional contribution to the increased invasive potential of tumor.

CONCLUSION

The findings are important in understanding the mechanisms of cancer progression and may affect therapeutic strategies for the patient.

Nucleoside diphosphate kinase B regulates angiogenesis through modulation of vascular endothelial growth factor receptor type 2 and endothelial adherens junction proteins

OBJECTIVE

Nucleoside diphosphate kinase B (NDPKB) participates in the activation of heterotrimeric and monomeric G proteins, which are pivotal mediators in angiogenic signaling. The role of NDPKB in angiogenesis has to date not been defined. Therefore, we analyzed the contribution of NDPKB to angiogenesis and its underlying mechanisms in well-characterized in vivo and in vitro models.

APPROACH AND RESULTS

Zebrafish embryos were depleted of NDPKB by morpholino-mediated knockdown. These larvae displayed severe malformations specifically in vessels formed by angiogenesis. NDPKB-deficient (NDPKB(-/-)) mice were subjected to oxygen-induced retinopathy. In this model, the number of preretinal neovascularizations in NDPKB(-/-) mice was strongly reduced in comparison with wild-type littermates. In accordance, a delayed blood flow recovery was detected in the NDPKB(-/-) mice after hindlimb ligation. In in vitro studies, a small interfering RNA-mediated knockdown of NDPKB was performed in human umbilical endothelial cells. NDPKB depletion impaired vascular endothelial growth factor (VEGF)-induced sprouting and hampered the VEGF-induced spatial redistributions of the VEGF receptor type 2 and VE-cadherin at the plasma membrane. Concomitantly, NDPKB depletion increased the permeability of the human umbilical endothelial cell monolayer.

CONCLUSIONS

This is the first report to show that NDPKB is required for VEGF-induced angiogenesis and contributes to the correct localization of VEGF receptor type 2 and VE-cadherin at the endothelial adherens junctions. Therefore, our data identify NDPKB as a novel molecular target to modulate VEGF-dependent angiogenesis.