Endothelial Cell Metabolism in Health and Disease

Effects of Berberine on Atherosclerosis

Atherosclerosis is an epidemic across the globe[A1], and its morbidity and mortality remain high, involving various complications and poor prognoses. In atherosclerosis, endothelial cells (ECs) dysfunction, vascular smooth muscle cells (VSMCs) migration and proliferation, foam cell formation, and inflammatory cell recruitment contribute to disease progression. Vascular stem cells (VSCs) also play a critical role in the cardiovascular system. Important data showed that the simultaneous increase of proliferation and apoptosis of VSMCs is the main cause of graft vein stenosis, suggesting that inhibition of VSMCs proliferation and apoptosis simultaneously is an important strategy for the treatment of atherosclerotic stenosis. Complementary and alternative medicine use among patients with cardiovascular disease (CVD) is growing. Berberine is an extract of Chinese traditional herbs that is known for its antimicrobial and anti-inflammatory effects in the digestive system. Its underlying anti-CVD mechanisms are currently attracting interest, and its pharmacological actions, such as antioxidation, regulation of neurotransmitters and enzymes, and cholesterol-lowering effects, have been substantiated. Recent studying found that berberine could inhibit both the proliferation and apoptosis of VSMCs induced by mechanical stretch stress simultaneously, which suggests that berberine might be an excellent drug to treat atherosclerosis. This review will focus on the recent progress of the effect of berberine on vascular cells, especially VSMCs, to provide important data and a new perspective for the application of berberine in anti-atherosclerosis.

Extracellular vesicles: General features and usefulness in diagnosis and therapeutic management of colorectal cancer

In the world, among all type of cancers, colorectal cancer (CRC) is the third most commonly diagnosed in males and the second in females. In most of cases, (RP1) patients’ prognosis limitation with malignant tumors can be attributed to delayed diagnosis of the disease. Identification of patients with early-stage disease leads to more effective therapeutic interventions. Therefore, new screening methods and further innovative treatment approaches are mandatory as they may lead to an increase in progression-free and overall survival rates. For the last decade, the interest in extracellular vesicles (EVs) research has exponentially increased as EVs generation appears to be a universal feature of every cell that is strongly involved in many mechanisms of cell-cell communication either in physiological or pathological situations. EVs can cargo biomolecules, such as lipids, proteins, nucleic acids and generate transmission signal through the intercellular transfer of their content. By this mechanism, tumor cells can recruit and modify the adjacent and systemic microenvironment to support further invasion and dissemination. This review intends to cover the most recent literature on the role of EVs production in colorectal normal and cancer tissues. Specific attention is paid to the use of EVs for early CRC diagnosis, follow-up, and prognosis as EVs have come into the spotlight of research as a high potential source of ‘liquid biopsies’. The use of EVs as new targets or nanovectors as drug delivery systems for CRC therapy is also summarized.

Involvement of multiple scavenger receptors in advanced glycation end product-induced vessel tube formation in endothelial cells

Toxic advanced glycation end products (toxic AGEs) derived from glycolaldehyde (AGE3) have been implicated in the development of diabetic vascular complications such as retinopathy characterised by excessive angiogenesis. Different receptor types, such as receptor for AGEs (RAGE), Toll like receptor-4 and scavenger receptors, are expressed in endothelial cells and contribute to AGE-elicited alteration of cell function. In the present study, we examined the involvement of AGE-related receptors on AGE-induced angiogenesis in endothelial cells. The effects of pharmacological inhibitors or receptor neutralizing antibodies on AGE3-induced tube formation were investigated using the in vitro Matrigel tube formation assay in b.End5 cells (mouse endothelial cells). AGE3-induced signalling pathways and receptor expression changes were analysed by Western blot analysis and flow cytometry, respectively. Both FPS-ZM1, a RAGE inhibitor, and fucoidan, a ligand for scavenger receptors, suppressed AGE3-induced tube formation. Cocktails of neutralizing antibodies against the scavenger receptors CD36, CD163 and LOX-1 prevented AGE3-induced tube formation. AGE3 activated mTOR signalling, resulting in facilitation of tube formation. Activation of the AGE-RAGE pathway also led to the upregulation of scavenger receptors. Taken together, our findings suggest that the scavenger receptors CD36, CD163 and LOX-1 in conjunction with the RAGE receptor work together to mediate toxic AGE-induced facilitation of angiogenesis.

Endothelial Heme Dynamics Drive Cancer Cell Metabolism by Shaping the Tumor Microenvironment

The crosstalk among cancer cells (CCs) and stromal cells within the tumor microenvironment (TME) has a prominent role in cancer progression. The significance of endothelial cells (ECs) in this scenario relies on multiple vascular functions. By forming new blood vessels, ECs support tumor growth. In addition to their angiogenic properties, tumor-associated ECs (TECs) establish a unique vascular niche that actively modulates cancer development by shuttling a selected pattern of factors and metabolites to the CC. The profile of secreted metabolites is strictly dependent on the metabolic status of the cell, which is markedly perturbed in TECs. Recent evidence highlights the involvement of heme metabolism in the regulation of energy metabolism in TECs. The present study shows that interfering with endothelial heme metabolism by targeting the cell membrane heme exporter Feline Leukemia Virus subgroup C Receptor 1a (FLVCR1a) in TECs, resulted in enhanced fatty acid oxidation (FAO). Moreover, FAO-derived acetyl-CoA was partly consumed through ketogenesis, resulting in ketone bodies (KBs) accumulation in FLVCR1a-deficient TECs. Finally, the results from this study also demonstrate that TECs-derived KBs can be secreted in the extracellular environment, inducing a metabolic rewiring in the CC. Taken together, these data may contribute to finding new metabolic vulnerabilities for cancer therapy.

Role of PKM2-Mediated Immunometabolic Reprogramming on Development of Cytokine Storm

The cytokine storm is a marker of severity of various diseases and increased mortality. The altered metabolic profile and energy generation of immune cells affects their activation, exacerbating the cytokine storm. Currently, the emerging field of immunometabolism has highlighted the importance of specific metabolic pathways in immune regulation. The glycolytic enzyme pyruvate kinase M2 (PKM2) is a key regulator of immunometabolism and bridges metabolic and inflammatory dysfunction. This enzyme changes its conformation thus walks in different fields including metabolism and inflammation and associates with various transcription factors. This review summarizes the vital role of PKM2 in mediating immunometabolic reprogramming and its role in inducing cytokine storm, with a focus on providing references for further understanding of its pathological functions and for proposing new targets for the treatment of related diseases.

Tumor Microenvironment of Esophageal Cancer

Simple Summary

Esophageal cancer is one of the top ten most deadly cancers. Even when diagnosed in a curable stage, patients prognosis poor. One of the parameters that is very relevant for long-term survival is response to radio(chemo)therapy prior surgery. Complete response rates are between 24 and 50 percent. This puts more than a half of every esophageal cancer patient that is diagnosed in a non-metastasized stage at high risk of recurrence. To improve response rates of treatment regimens prior curative surgery is, therefore, a major challenge in treating esophageal cancer. Not only the response of the cancer cell itself to cancer therapy is determining patients’ fate. Cells around the tumor cells called the tumor microenvironment that together with the cancer cell constitute a malignant tumor are also involved in tumor progression and therapy response. This review depicts the most important parts of the esophageal cancer microenvironment, evaluates chances and challenges of current already established therapeutic concepts that target this microenvironment. It furthermore elucidates specific pathways that are potential valuable targets in the future.

Abstract

Esophageal cancer is among the top ten most deadly cancers worldwide with adenocarcinomas of the esophagus showing increasing incidences over the last years. The prognosis is determined by tumor stage at diagnosis and in locally advanced stages by response to (radio-)chemotherapy followed by radical surgery. Less than a third of patients with esophageal adenocarcinomas completely respond to neoadjuvant therapies which urgently asks for further strategies to improve these rates. Aiming at the tumor microenvironment with novel targeted therapies can be one strategy to achieve this goal. This review connects experimental, translational, and clinical findings on each component of the esophageal cancer tumor microenvironment involving tumor angiogenesis, tumor-infiltrating immune cells, such as macrophages, T-cells, myeloid-derived suppressor cells, and cancer-associated fibroblasts. The review evaluates the current state of already approved concepts and depicts novel potentially targetable pathways related to esophageal cancer tumor microenvironment.

Combined Treatment with Acalabrutinib and Rapamycin Inhibits Glioma Stem Cells and Promotes Vascular Normalization by Downregulating BTK/mTOR/VEGF Signaling

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults, with a median duration of survival of approximately 14 months after diagnosis. High resistance to chemotherapy remains a major problem. Previously, BTK has been shown to be involved in the intracellular signal transduction including Akt/mTOR signaling and be critical for tumorigenesis. Thus, we aim to evaluate the effect of BTK and mTOR inhibition in GBM. We evaluated the viability of GBM cell lines after treatment with acalabrutinib and/or rapamycin through a SRB staining assay. We then evaluated the effect of both drugs on GBM stem cell-like phenotypes through various in vitro assay. Furthermore, we incubated HUVEC cells with tumorsphere conditioned media and observed their angiogenesis potential, with or without treatment. Finally, we conducted an in vivo study to confirm our in vitro findings and analyzed the effect of this combination on xenograft mice models. Drug combination assay demonstrated a synergistic relationship between acalabrutinib and rapamycin. CSCs phenotypes, including tumorsphere and colony formation with the associated expression of markers of pluripotency are inhibited by either acalabrutinib or rapamycin singly and these effects are enhanced upon combining acalabrutinib and rapamycin. We showed that the angiogenesis capabilities of HUVEC cells are significantly reduced after treatment with acalabrutinib and/or rapamycin. Xenograft tumors treated with both drugs showed significant volume reduction with minimal toxicity. Samples taken from the combined treatment group demonstrated an increased Desmin/CD31 and col IV/vessel ratio, suggesting an increased rate of vascular normalization. Our results demonstrate that BTK-mTOR inhibition disrupts the population of GBM-CSCs and contributes to normalizing GBM vascularization and thus, may serve as a basis for developing therapeutic strategies for chemoresistant/radioresistant GBM.

Early Life Stress and Metabolic Plasticity of Brain Cells: Impact on Neurogenesis and Angiogenesis

Early life stress (ELS) causes long-lasting changes in brain plasticity induced by the exposure to stress factors acting prenatally or in the early postnatal ontogenesis due to hyperactivation of hypothalamic-pituitary-adrenal axis and sympathetic nervous system, development of neuroinflammation, aberrant neurogenesis and angiogenesis, and significant alterations in brain metabolism that lead to neurological deficits and higher susceptibility to development of brain disorders later in the life. As a key component of complex pathogenesis, ELS-mediated changes in brain metabolism associate with development of mitochondrial dysfunction, loss of appropriate mitochondria quality control and mitochondrial dynamics, deregulation of metabolic reprogramming. These mechanisms are particularly critical for maintaining the pool and development of brain cells within neurogenic and angiogenic niches. In this review, we focus on brain mitochondria and energy metabolism related to tightly coupled neurogenic and angiogenic events in healthy and ELS-affected brain, and new opportunities to develop efficient therapeutic strategies aimed to restore brain metabolism and reduce ELS-induced impairments of brain plasticity.

The Role of Adenosine Receptor A2A in the Regulation of Macrophage Exosomes and Vascular Endothelial Cells During Bone Healing

Background

Macrophage exosomes and vascular endothelial cells (VECs) are critical to bone healing. However, few studies explore the molecular regulation of them in the bone fracture microenvironment.

Methods

In this study, we explored the effects of adenosine receptor A2A (ADA2AR) in macrophage exosomes and VECs during bone healing. CGS21680 (an ADA2AR agonist) and ZM241385 (an ADA2AR antagonist) were used. First, the effects of the ADA2AR on VECs during bone healing were studied in vivo in a rat tibial fracture model. Second, the effects of ADA2AR on VECs and in the regulation of VECs by macrophages were examined in the bone fracture microenvironment. Third, the effects of ADA2AR on the regulation of macrophage exosomes on VECs were analyzed. Finally, the genes and long non-coding RNAs (lncRNAs) associated with the regulation of VECs by the ADA2AR were examined by high-throughput sequencing and bioinformatics analysis.

Results

CGS21680 accelerated VEC proliferation in the early stage of bone healing and that ZM241385 suppressed VEC proliferation in vivo. ZM241385 inhibited cell viability and tube formation in vitro. However, CGS21680 did not promote tube formation, cell proliferation, or cell migration in vitro. The inhibition of macrophage exosomes could suppress tube formation and VEC migration. CGS21680 had no effects on tube formation in a macrophage-VEC co-culture. The macrophage exosomes were purified and CGS21680 promoted the macrophage secretion of exosomes. In contrast, ZM241385 inhibited the macrophage secretion exosomes. Finally, the lncRNA and mRNA involved in the activation of the ADA2AR in VECs were analyzed. CGS21680 upregulated 3274 mRNAs and downregulated 2236 mRNAs, and upregulated 1696 lncRNAs and downregulated 1882 lncRNAs. The hub genes involved in angiogenesis were Flt1, Fgf2, Mapk14, Fn1, and Jun.

Conclusion

The activation of ADA2AR was essential for angiogenesis and the secretion of exosomes by macrophages during bone healing; moreover, the inactivation of the ADA2AR led to poor angiogenesis and bone nonunion.

Endothelial GABBR2 Regulates Post-ischemic Angiogenesis by Inhibiting the Glycolysis Pathway

Purpose: Angiogenesis post-ischemia plays an essential role in preventing ischemic damage to tissue by improving the blood recovery. Determining the regulatory mechanism of ischemic angiogenesis, therefore, could provide effective therapeutics for ischemic injury. Materials and Methods: The RNA sequencing (RNA-seq) database was used to predict the association of gamma-aminobutyric acid type B receptor subunit 2 (GABBR2) with endothelial-specific expression. The role of GABBR2 in angiogenesis was verified in vitro by downregulating GABBR2 in human umbilical vein endothelial cells (HUVECs) with lentiviral vectors. Besides, the in vivo effect of GABBR2 on the blood recovery of an ischemic hindlimb was demonstrated by establishing a hindlimb ischemia model in normal and GABBR2 adenoviral vector-infected mice. Then, the mobilization of endothelial progenitor cells (EPCs) in peripheral blood post-ischemia was determined by flow cytometry. Finally, the XF analyzer and Western blot were used to determine the effect of GABBR2 on endothelial metabolism. Results: The RNA-seq results indicated a strong association between GABBR2 and endothelial revascularization, and the upregulation of GABBR2 was detected in both hypoxia-treated HUVECs and ischemic mouse hindlimb. Hypoxia treatment for 6 h increased the proliferation, migration, and tube formation of HUVECs, which were inhibited by GABBR2 knockdown. Additionally, GABBR2 downregulation significantly decreased the blood flow recovery of mouse ischemic hindlimb. The expressions of the EPC markers CD34⁺ and CD133⁺ significantly decreased in the peripheral blood in hindlimb post-ischemia. Mechanically, glycolysis-dominated metabolism of HUVECs was compromised by GABBR2 knockdown. Evidences of the decreased expressions of HKII, PFKFB3, and PKM1 also supported the compromised glycolysis induced by GABBR2 downregulation. Conclusion: Our study demonstrated that GABBR2 regulated angiogenesis post-ischemia by inhibiting the glycolysis pathway.

The therapeutic effect and mechanism of Qishen Yiqi dripping pills on cardiovascular and cerebrovascular diseases and diabetic complications

The alterations in vascular homeostasis is deeply involved in the development of numerous diseases, such as coronary heart disease, stroke, and diabetic complications. Changes in blood flow and endothelial permeability caused by vascular dysfunction are the common mechanisms for these three types of diseases. The disorders of glucose and lipid metabolism can result in changes of the energy production patterns in endothelium and surrounding cells which may consequently cause local energy metabolic disorders, oxidative stress and inflammatory responses. Traditional Chinese medicine (TCM) follows the principle of the "treatment by the syndrome differentiation". TCM considers of that coronary heart disease, stroke and diabetes complications all as the type of "Qi deficiency and Blood stasis" syndrome, which mainly happens to the vascular system. Therefore, the common pathogenesis of these three types of diseases suggests the treatment strategy by TCM should be in a close manner and named as "treating different diseases by the same treatment". Qishen Yiqi dripping pills is a modern Chinese herbal medicine which has been widely used for treatment of patients with coronary heart disease characterized as "Qi deficiency and blood stasis" in China. Recently, many clinical reports have demonstrated the potent therapeutic effects of Qishen Yiqi dripping pills on ischemic stroke and diabetic nephropathy. Based on these reports, we will summarize the clinical applications of Qishen Yiqi dripping pills on coronary heart disease, ischemic stroke and diabetic nephropathy, including the involved mechanisms with basic researches.

Activating transcription factor 4 regulates angiogenesis under lipid overload via methionine adenosyltransferase 2A-mediated endothelial epigenetic alteration

Lipid overload is intimately connected with the change of endothelial epigenetic status which impacts cellular signaling activities and endothelial function. Activating transcription factor 4 (ATF4) is involved in the regulation of lipid metabolism and meanwhile an epigenetic modifier. However, the role of ATF4 in the angiogenesis under lipid overload is not well understood. Here, to induce lipid overload status, we employed high-fat diet (HFD)-induced obese mouse model in vivo and palmitic acid (PA) to stimulate endothelial cells in vitro. Compared with mice fed with normal chow diet (NCD), HFD-induced obese mice showed angiogenic defects evidenced by decline in (1) blood flow recovery after hind limb ischemia, (2) wound healing speed after skin injury, (3) capillary density in injured tissues and matrigel plugs, and (4) endothelial sprouts of aortic ring. ATF4 deficiency aggravated above angiogenic defects in mice while ATF4 overexpression improved the blunted angiogenic response. Mechanistically, lipid overload lowered the H3K4 methylation levels at the regulatory regions of NOS3 and ERK1 genes, leading to reduced angiogenic signaling activity. Methionine adenosyltransferase 2A (MAT2A) is identified as a target of ATF4 and formed complex with ATF4 to direct lysine methyltransferase 2A (MLL1) to the regulatory regions of both genes for the maintenance of the H3K4 methylation level and angiogenic signaling activity. Here, we uncovered a novel metabolic-epigenetic coupling orchestrated by the ATF4-MAT2A axis for angiogenesis. The ATF4-MAT2A axis links lipid overload milieu to altered epigenetic status of relevant angiogenic signaling in endothelial cells, suggesting a potential therapeutic target for angiogenesis impaired by lipid overload.

Normalization in tumor ecosystem: Opportunities and challenges

Current research in cancer therapy aims to exploit efficient strategies to have long-lasting effects on tumors and to reduce or even revoke the chance of recurrence. Within the tumor stroma, O₂ and nutrients are abnormally distributed between various cells (preferentially for supplying cancer cells), the immune contexture is abnormally positioned (permissive essentially for cells exhibiting tumor-promoting capacity), the fibroblast and fibrotic content is abnormally distributed (presence of both extracellular matrix [ECM] stiffening and ECM-degrading factors both for tumor-promoting purposes), and the tumor vasculature is abnormally orchestrated (for hindering drug delivery and increasing the chance of tumor metastasis). Resistance is actually an adaptive response to an imbalance in the tumor ecosystem; thus, the key consideration for effective cancer therapy is to bring back the normal status in this ecosystem so as to reach the desired durable outcome. Vascular normalization, metabolic modulation (glucose delivery in particular), balancing cellular dispersion, and balancing the pH rate and O₂ delivery within the tumor microenvironment are suggested strategies to reverse abnormality within the tumor stroma.

Vascular Endothelial Senescence: Pathobiological Insights, Emerging Long Noncoding RNA Targets, Challenges and Therapeutic Opportunities

Cellular senescence is a stable form of cell cycle arrest in response to various stressors. While it serves as an endogenous pro-resolving mechanism, detrimental effects ensue when it is dysregulated. In this review, we introduce recent advances for cellular senescence and inflammaging, the underlying mechanisms for the reduction of nicotinamide adenine dinucleotide in tissues during aging, new knowledge learned from p16 reporter mice, and the development of machine learning algorithms in cellular senescence. We focus on pathobiological insights underlying cellular senescence of the vascular endothelium, a critical interface between blood and all tissues. Common causes and hallmarks of endothelial senescence are highlighted as well as recent advances in endothelial senescence. The regulation of cellular senescence involves multiple mechanistic layers involving chromatin, DNA, RNA, and protein levels. New targets are discussed including the roles of long noncoding RNAs in regulating endothelial cellular senescence. Emerging small molecules are highlighted that have anti-aging or anti-senescence effects in age-related diseases and impact homeostatic control of the vascular endothelium. Lastly, challenges and future directions are discussed including heterogeneity of endothelial cells and endothelial senescence, senescent markers and detection of senescent endothelial cells, evolutionary differences for immune surveillance in mice and humans, and long noncoding RNAs as therapeutic targets in attenuating cellular senescence. Accumulating studies indicate that cellular senescence is reversible. A better understanding of endothelial cellular senescence through lifestyle and pharmacological interventions holds promise to foster a new frontier in the management of cardiovascular disease risk.

Ketogenic Metabolic Therapy, Without Chemo or Radiation, for the Long-Term Management of IDH1-Mutant Glioblastoma: An 80-Month Follow-Up Case Report

Background: Successful treatment of glioblastoma (GBM) remains futile despite decades of intense research. GBM is similar to most other malignant cancers in requiring glucose and glutamine for growth, regardless of histological or genetic heterogeneity. Ketogenic metabolic therapy (KMT) is a non-toxic nutritional intervention for cancer management. We report the case of a 32-year-old man who presented in 2014 with seizures and a right frontal lobe tumor on MRI. The tumor cells were immunoreactive with antibodies to the IDH1 (R132H) mutation, P53 (patchy), MIB-1 index (4–6%), and absent ATRX protein expression. DNA analysis showed no evidence of methylation of the MGMT gene promoter. The presence of prominent microvascular proliferation and areas of necrosis were consistent with an IDH-mutant glioblastoma (WHO Grade 4).

Methods: The patient refused standard of care (SOC) and steroid medication after initial diagnosis, but was knowledgeable and self-motivated enough to consume a low-carbohydrate ketogenic diet consisting mostly of saturated fats, minimal vegetables, and a variety of meats. The patient used the glucose ketone index calculator to maintain his Glucose Ketone Index (GKI) near 2.0 without body weight loss.

Results: The tumor continued to grow slowly without expected vasogenic edema until 2017, when the patient opted for surgical debulking. The enhancing area, centered in the inferior frontal gyrus, was surgically excised. The pathology specimen confirmed IDH1-mutant GBM. Following surgery, the patient continued with a self-administered ketogenic diet to maintain low GKI values, indicative of therapeutic ketosis. At the time of this report (May 2021), the patient remains alive with a good quality of life, except for occasional seizures. MRI continues to show slow interval progression of the tumor.

Conclusion: This is the first report of confirmed IDH1-mutant GBM treated with KMT and surgical debulking without chemo- or radiotherapy. The long-term survival of this patient, now at 80 months, could be due in part to a therapeutic metabolic synergy between KMT and the IDH1 mutation that simultaneously target the glycolysis and glutaminolysis pathways that are essential for GBM growth. Further studies are needed to determine if this non-toxic therapeutic strategy could be effective in providing long-term management for other GBM patients with or without IDH mutations.

The Activation of Endothelial Cells Relies on a Ferroptosis-Like Mechanism: Novel Perspectives in Management of Angiogenesis and Cancer Therapy

The activation of endothelial cells (ECs) is a crucial step on the road map of tumor angiogenesis and expanding evidence indicates that a pro-oxidant tumor microenvironment, conditioned by cancer metabolic rewiring, is a relevant controller of this process. Herein, we investigated the contribution of oxidative stress-induced ferroptosis to ECs activation. Moreover, we also addressed the anti-angiogenic effect of Propranolol. We observed that a ferroptosis-like mechanism, induced by xCT inhibition with Erastin, at a non-lethal level, promoted features of ECs activation, such as proliferation, migration and vessel-like structures formation, concomitantly with the depletion of reduced glutathione (GSH) and increased levels of oxidative stress and lipid peroxides. Additionally, this ferroptosis-like mechanism promoted vascular endothelial cadherin (VE-cadherin) junctional gaps and potentiated cancer cell adhesion to ECs and transendothelial migration. Propranolol was able to revert Erastin-dependent activation of ECs and increased levels of hydrogen sulfide (H₂S) underlie the mechanism of action of Propranolol. Furthermore, we tested a dual-effect therapy by promoting ECs stability with Propranolol and boosting oxidative stress to induce cancer cell death with a nanoformulation comprising selenium-containing chrysin (SeChry) encapsulated in a fourth generation polyurea dendrimer (SeChry@PURE_G4). Our data showed that novel developments in cancer treatment may rely on multi-targeting strategies focusing on nanoformulations for a safer induction of cancer cell death, taking advantage of tumor vasculature stabilization.

Mesenchymal stem cell-derived extracellular vesicles in the failing heart: past, present, and future

Cardiovascular disease (CVD) is the leading cause of death globally. Current treatment options include lifestyle changes, medication, and surgical intervention. However, many patients are unsuitable candidates for surgeries due to comorbidities, diffuse coronary artery disease, or advanced stages of heart failure. The search for new treatment options has recently transitioned from cell-based therapies to stem-cell-derived extracellular vesicles (EVs). A number of challenges remain in the EV field, including the effect of comorbidities, characterization, and delivery. However, recent revolutionary developments and insight into the potential of personalizing EV contents by bioengineering methods to alter specific signaling pathways in the ischemic myocardium hold promise. Here, we discuss the past limitations of cell-based therapies and recent EV studies involving in vivo, in vitro, and omics, and future challenges and opportunities in EV-based treatments in CVD.

The changing landscape of atherosclerosis

Emerging evidence has spurred a considerable evolution of concepts relating to atherosclerosis, and has called into question many previous notions. Here I review this evidence, and discuss its implications for understanding of atherosclerosis. The risk of developing atherosclerosis is no longer concentrated in Western countries, and it is instead involved in the majority of deaths worldwide. Atherosclerosis now affects younger people, and more women and individuals from a diverse range of ethnic backgrounds, than was formerly the case. The risk factor profile has shifted as levels of low-density lipoprotein (LDL) cholesterol, blood pressure and smoking have decreased. Recent research has challenged the protective effects of high-density lipoprotein, and now focuses on triglyceride-rich lipoproteins in addition to low-density lipoprotein as causal in atherosclerosis. Non-traditional drivers of atherosclerosis-such as disturbed sleep, physical inactivity, the microbiome, air pollution and environmental stress-have also gained attention. Inflammatory pathways and leukocytes link traditional and emerging risk factors alike to the altered behaviour of arterial wall cells. Probing the pathogenesis of atherosclerosis has highlighted the role of the bone marrow: somatic mutations in stem cells can cause clonal haematopoiesis, which represents a previously unrecognized but common and potent age-related contributor to the risk of developing cardiovascular disease. Characterizations of the mechanisms that underpin thrombotic complications of atherosclerosis have evolved beyond the 'vulnerable plaque' concept. These advances in our understanding of the biology of atherosclerosis have opened avenues to therapeutic interventions that promise to improve the prevention and treatment of now-ubiquitous atherosclerotic diseases.

Does exercise training improve the function of vascular smooth muscle? A systematic review and meta-analysis

We aimed to determine the effects of exercise training on the function of vascular smooth muscle cells. PubMed and Web of Science about the effects of exercise training on vascular smooth muscle cells were searched up to August 2020. The effect sizes were estimated in terms of the standardized mean difference. The number of studies included was thirty-five overall. Exercise training had positive effects on vascular smooth muscle cells function in participants older than 40. Effect sizes for HIGH intensity and MIX were positive but small, and also when training duration was longer than 12 weeks. We concluded that vascular smooth muscle cells response can be promoted by exercise training. Vigorous aerobic exercise and mixture training modality were the best ways to promote the dilation response of vascular smooth muscle cells. Additionally, the significant improvement induced by exercise training only occurred when training lasted for longer than 12 weeks.

Roxarsone Promotes Glycolysis and Angiogenesis by Inducing Hypoxia-Inducible Factor-1α In Vitro and In Vivo

Roxarsone (Rox) is an organic arsenic compound used as a feed additive to promote animal growth. The release of Rox into the environment poses risks to human health. Rox demonstrated tumor-promoting and proangiogenic effects in xenograft models. Increasing studies revealed the tight relationship among angiogenesis, carcinogenesis, tumorigenesis, and glycolysis. Glycolysis, via hypoxia-inducible factor-1α (HIF-1α), controls vascular endothelial cell (VEC) growth. To date, there has been no literature report on the effect of Rox on HIF-1α-dependent glycolysis. Herein, we report that Rox promoted glycolysis in rat VECs, as shown by the increased adenosine triphosphate production, the lactic acid release, the activity and content of aldolase (ALD), and the expression levels of ALD A and glucose transporter 1 (GLUT1). Rox also increased the cellular levels of HIF-1α. Treatment with the HIF-1α inhibitor YC-1 reversed Rox-increased ALD A and GLUT1 levels and attenuated Rox-induced VEC viability, suggesting that Rox-induced HIF-1α contributes to the glycolytic and angiogenic effects of Rox. Rox also promoted tumor growth and angiogenesis and increased the levels of ALD A, GLUT1, and HIF-1α in the tumor tissue of a mouse xenograft model, whereas these effects were abolished using YC-1. Our findings indicated that Rox induces HIF-1α in VECs to promote glycolysis and angiogenesis thus enhancing the tumor growth.

Anti-Angiogenic Therapy: Current Challenges and Future Perspectives

Anti-angiogenic therapy is an old method to fight cancer that aims to abolish the nutrient and oxygen supply to the tumor cells through the decrease of the vascular network and the avoidance of new blood vessels formation. Most of the anti-angiogenic agents approved for cancer treatment rely on targeting vascular endothelial growth factor (VEGF) actions, as VEGF signaling is considered the main angiogenesis promotor. In addition to the control of angiogenesis, these drugs can potentiate immune therapy as VEGF also exhibits immunosuppressive functions. Despite the mechanistic rational that strongly supports the benefit of drugs to stop cancer progression, they revealed to be insufficient in most cases. We hypothesize that the rehabilitation of old drugs that interfere with mechanisms of angiogenesis related to tumor microenvironment might represent a promising strategy. In this review, we deepened research on the molecular mechanisms underlying anti-angiogenic strategies and their failure and went further into the alternative mechanisms that impact angiogenesis. We concluded that the combinatory targeting of alternative effectors of angiogenic pathways might be a putative solution for anti-angiogenic therapies.

Effects of the Novel PFKFB3 Inhibitor KAN0438757 on Colorectal Cancer Cells and Its Systemic Toxicity Evaluation In Vivo

BACKGROUND

Despite substantial progress made in the last decades in colorectal cancer (CRC) research, new treatment approaches are still needed to improve patients' long-term survival. To date, the promising strategy to target tumor angiogenesis metabolically together with a sensitization of CRC to chemo- and/or radiotherapy by PFKFB3 (6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-3) inhibition has never been tested. Therefore, initial evaluation and validation of newly developed compounds such as KAN0438757 and their effects on CRC cells are crucial steps preceding to in vivo preclinical studies, which in turn may consolidate new therapeutic targets.

MATERIALS AND METHODS

The efficiency of KAN0438757 to block PFKFB3 expression and translation in human CRC cells was evaluated by immunoblotting and real-time PCR. Functional in vitro assays assessed the effects of KAN0438757 on cell viability, proliferation, survival, adhesion, migration and invasion. Additionally, we evaluated the effects of KAN0438757 on matched patient-derived normal and tumor organoids and its systemic toxicity in vivo in C57BL6/N mice.

RESULTS

High PFKFB3 expression is correlated with a worse survival in CRC patients. KAN0438757 reduces PFKFB3 protein expression without affecting its transcriptional regulation. Additionally, a concentration-dependent anti-proliferative effect was observed. The migration and invasion capacity of cancer cells were significantly reduced, independent of the anti-proliferative effect. When treating colonic patient-derived organoids with KAN0438757 an impressive effect on tumor organoids growth was apparent, surprisingly sparing normal colonic organoids. No high-grade toxicity was observed in vivo.

CONCLUSION

The PFKFB3 inhibitor KAN0438757 significantly reduced CRC cell migration, invasion and survival. Moreover, on patient-derived cancer organoids KAN0438757 showed significant effects on growth, without being overly toxic in normal colon organoids and healthy mice. Our findings strongly encourage further translational studies to evaluate KAN0438757 in CRC therapy.

Integrin Regulation in Immunological and Cancerous Cells and Exosomes

Integrins represent the biologically and medically significant family of cell adhesion molecules that govern a wide range of normal physiology. The activities of integrins in cells are dynamically controlled via activation-dependent conformational changes regulated by the balance of intracellular activators, such as talin and kindlin, and inactivators, such as Shank-associated RH domain interactor (SHARPIN) and integrin cytoplasmic domain-associated protein 1 (ICAP-1). The activities of integrins are alternatively controlled by homotypic lateral association with themselves to induce integrin clustering and/or by heterotypic lateral engagement with tetraspanin and syndecan in the same cells to modulate integrin adhesiveness. It has recently emerged that integrins are expressed not only in cells but also in exosomes, important entities of extracellular vesicles secreted from cells. Exosomal integrins have received considerable attention in recent years, and they are clearly involved in determining the tissue distribution of exosomes, forming premetastatic niches, supporting internalization of exosomes by target cells and mediating exosome-mediated transfer of the membrane proteins and associated kinases to target cells. A growing body of evidence shows that tumor and immune cell exosomes have the ability to alter endothelial characteristics (proliferation, migration) and gene expression, some of these effects being facilitated by vesicle-bound integrins. As endothelial metabolism is now thought to play a key role in tumor angiogenesis, we also discuss how tumor cells and their exosomes pleiotropically modulate endothelial functions in the tumor microenvironment.

Analysis of Differentially Expressed Genes in Endothelial Cells Following Tumor Cell Adhesion, and the Role of PRKAA2 and miR-124-3p

Tumor cell adhesion to the endothelium is one pattern of tumor-endothelium interaction and a key step during tumor metastasis. Endothelium integrity is an important barrier to prevent tumor invasion and metastasis. Changes in endothelial cells (ECs) due to tumor cell adhesion provide important signaling mechanisms for the angiogenesis and metastasis of tumor cells. However, the changes happened in endothelial cells when tumor-endothelium interactions are still unclear. In this study, we used Affymetrix Gene Chip Human Transcriptome Array 2.0. and quantitative real-time PCR (qPCR) to clarify the detailed gene alteration in endothelial cells adhered by prostate tumor cells PC-3M. A total of 504 differentially expressed mRNAs and 444 lncRNAs were obtained through chip data analysis. Gene Ontology (GO) function analysis showed that differentially expressed genes (DEGs) mainly mediated gland development and DNA replication at the biological level; at the cell component level, they were mainly involved in the mitochondrial inner membrane; and at the molecular function level, DEGs were mainly enriched in ATPase activity and catalytic activity. Kyoto Encyclopedia of Genes and Genomes (KEGG) signal pathway analysis showed that the DEGs mainly regulated pathways in cancer, cell cycle, pyrimidine metabolism, and the mTOR signaling pathway. Then, we constructed a protein-protein interaction functional network and mRNA-lncRNA interaction network using Cytoscape v3.7.2. to identify core genes, mRNAs, and lncRNAs. The miRNAs targeted by the core mRNA PRKAA2 were predicted using databases (miRDB, RNA22, and Targetscan). The qPCR results showed that miR-124-3p, the predicted target miRNA of PRKAA2, was significantly downregulated in endothelial cells adhered by PC-3M. With a dual luciferase reporter assay, the binding of miR-124-3p with PRKAA2 3'UTR was confirmed. Additionally, by using the knockdown lentiviral vectors of miR-124-3p to downregulate the miR-124-3p expression level in endothelial cells, we found that the expression level of PRKAA2 increased accordingly. Taken together, the adhesion of tumor cells had a significant effect on mRNAs and lncRNAs in the endothelial cells, in which PRKAA2 is a notable changed molecule and miR-124-3p could regulate its expression and function in endothelial cells.

Metabolic Reprogramming of Vascular Endothelial Cells: Basic Research and Clinical Applications

Vascular endothelial cells (VECs) build a barrier separating the blood from the vascular wall. The vascular endothelium is the largest endocrine organ, and is well-known for its crucial role in the regulation of vascular function. The initial response to endothelial cell injury can lead to the activation of VECs. However, excessive activation leads to metabolic pathway disruption, VEC dysfunction, and angiogenesis. The pathways related to VEC metabolic reprogramming recently have been considered as key modulators of VEC function in processes such as angiogenesis, inflammation, and barrier maintenance. In this review, we focus on the changes of VEC metabolism under physiological and pathophysiological conditions.

Selective glutamine metabolism inhibition in tumor cells improves antitumor T lymphocyte activity in triple-negative breast cancer

Rapidly proliferating tumor and immune cells need metabolic programs that support energy and biomass production. The amino acid glutamine is consumed by effector T cells and glutamine-addicted triple-negative breast cancer (TNBC) cells, suggesting that a metabolic competition for glutamine may exist within the tumor microenvironment, potentially serving as a therapeutic intervention strategy. Here, we report that there is an inverse correlation between glutamine metabolic genes and markers of T cell-mediated cytotoxicity in human basal-like breast cancer (BLBC) patient data sets, with increased glutamine metabolism and decreased T cell cytotoxicity associated with poor survival. We found that tumor cell-specific loss of glutaminase (GLS), a key enzyme for glutamine metabolism, improved antitumor T cell activation in both a spontaneous mouse TNBC model and orthotopic grafts. The glutamine transporter inhibitor V-9302 selectively blocked glutamine uptake by TNBC cells but not CD8+ T cells, driving synthesis of glutathione, a major cellular antioxidant, to improve CD8+ T cell effector function. We propose a "glutamine steal" scenario, in which cancer cells deprive tumor-infiltrating lymphocytes of needed glutamine, thus impairing antitumor immune responses. Therefore, tumor-selective targeting of glutamine metabolism may be a promising therapeutic strategy in TNBC.

Increased Environment-Related Metabolism and Genetic Expression in the In Vitro Matured Mouse Oocytes by Transcriptome Analysis

Infertility in humans at their reproductive age is a world-wide problem. Oocyte in vitro maturation (IVM) is generally used in such cases to acquire the embryo in assisted reproductive technology (ART). However, the differences between an in vivo (IVO) and IVM culture environment in the RNA expression profile in oocytes, remains unclear. In this study, we compared the global RNA transcription pattern of oocytes from in vitro and in vivo maturation. Our results showed that 1,864 genes differentially expressed between the IVO and IVM oocytes. Among these, 1,638 genes were up-regulated, and 226 genes were down-regulated, and these changes were mainly divided into environmental adaption, metabolism, and genetic expression. Our detailed analysis showed that the expression of genes that belonged to metabolism-related processes such as energy metabolism, nucleotide metabolism, and carbohydrate metabolism was changed; and these genes also belonged to organismal systems including environmental adaptation and the circulatory system; moreover, we also found that the relative gene expression of genetic expression processes, such as protein synthesis, modification, and DNA replication and repair were also altered. In conclusion, our data suggests that in vitro maturation of mouse oocyte resulted in metabolism and genetic expression changes due to environmental changes compared with in vivo matured oocytes.

Endothelial Cell Glucose Metabolism and Angiogenesis

Angiogenesis, a process of new blood vessel formation from the pre-existing vascular bed, is a critical event in various physiological and pathological settings. Over the last few years, the role of endothelial cell (EC) metabolism in angiogenesis has received considerable attention. Accumulating studies suggest that ECs rely on aerobic glycolysis, rather than the oxidative phosphorylation pathway, to produce ATP during angiogenesis. To date, numerous critical regulators of glucose metabolism, fatty acid oxidation, and glutamine metabolism have been identified to modulate the EC angiogenic switch and pathological angiogenesis. The unique glycolytic feature of ECs is critical for cell proliferation, migration, and responses to environmental changes. In this review, we provide an overview of recent EC glucose metabolism studies, particularly glycolysis, in quiescent and angiogenic ECs. We also summarize and discuss potential therapeutic strategies that take advantage of EC metabolism. The elucidation of metabolic regulation and the precise underlying mechanisms could facilitate drug development targeting EC metabolism to treat angiogenesis-related diseases.

Intercellular Communication by Vascular Endothelial Cell-Derived Extracellular Vesicles and Their MicroRNAs in Respiratory Diseases

Respiratory diseases and their comorbidities, such as cardiovascular disease and muscle atrophy, have been increasing in the world. Extracellular vesicles (EVs), which include exosomes and microvesicles, are released from almost all cell types and play crucial roles in intercellular communication, both in the regulation of homeostasis and the pathogenesis of various diseases. Exosomes are of endosomal origin and range in size from 50 to 150 nm in diameter, while microvesicles are generated by the direct outward budding of the plasma membrane in size ranges of 100-2,000 nm in diameter. EVs can contain various proteins, metabolites, and nucleic acids, such as mRNA, non-coding RNA species, and DNA fragments. In addition, these nucleic acids in EVs can be functional in recipient cells through EV cargo. The endothelium is a distributed organ of considerable biological importance, and disrupted endothelial function is involved in the pathogenesis of respiratory diseases such as chronic obstructive pulmonary disease, pulmonary hypertension, and acute respiratory distress syndrome. Endothelial cell-derived EVs (EC-EVs) play crucial roles in both physiological and pathological conditions by traveling to distant sites through systemic circulation. This review summarizes the pathological roles of vascular microRNAs contained in EC-EVs in respiratory diseases, mainly focusing on chronic obstructive pulmonary disease, pulmonary hypertension, and acute respiratory distress syndrome. Furthermore, this review discusses the potential clinical usefulness of EC-EVs as therapeutic agents in respiratory diseases.

MALAT1 sponges miR-26a and miR-26b to regulate endothelial cell angiogenesis via PFKFB3-driven glycolysis in early-onset preeclampsia

6-phosphofructo-2-kinase (PFKFB3) is a crucial regulator of glycolysis that has been implicated in angiogenesis and the development of diverse diseases. However, the functional role and regulatory mechanism of PFKFB3 in early-onset preeclampsia (EOPE) remain to be elucidated. According to previous studies, noncoding RNAs play crucial roles in EOPE pathogenesis. The goal of this study was to investigate the functional roles and co-regulatory mechanisms of the metastasis-associated lung adenocarcinoma transcript-1 (MALAT1)/microRNA (miR)-26/PFKFB3 axis in EOPE. In our study, decreased MALAT1 and PFKFB3 expression in EOPE tissues correlates with endothelial cell (EC) dysfunction. The results of in vitro assays revealed that PFKFB3 regulates the proliferation, migration, and tube formation of ECs by modulating glycolysis. Furthermore, MALAT1 regulates PFKFB3 expression by sponging miR-26a/26b. Finally, MALAT1 knockout reduces EC angiogenesis by inhibiting PFKFB3-mediated glycolysis flux, which is ameliorated by PFKFB3 overexpression. In conclusion, decreased MALAT1 expression in EOPE tissues reduces the glycolysis of ECs in a PFKFB3-dependent manner by sponging miR-26a/26b and inhibits EC proliferation, migration, and tube formation, which may contribute to abnormal angiogenesis in EOPE. Thus, strategies targeting PFKFB3-driven glycolysis may be a promising approach for the treatment of EOPE.

Microarray expression profile of mRNAs and long noncoding RNAs and the potential role of PFK-1 in infantile hemangioma

BACKGROUND

Infantile hemangioma (IH) is the most common benign tumor in children. Long noncoding RNAs (lncRNAs) play a critical role in tumorigenesis. However, the expression levels and biological functions of lncRNAs in IH have not been well-studied. This study aimed to analyze the expression profile of lncRNAs and mRNAs in proliferating and involuting IHs.

METHODS

The expression profiles of lncRNAs and mRNAs in proliferating and involuting IHs were identified by microarray analysis. Subsequently, detailed bioinformatics analyses were performed. Finally, quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC) analyses were conducted to validate the microarray results.

RESULTS

In total, 146 differentially expressed (DE) lncRNAs and 374 DE mRNAs were identified. The DE mRNAs were enriched mostly in angiogenesis-related biological processes (BPs) and pathways by bioinformatics analysis. In addition, metabolism-related BPs (e.g., "glycogen biosynthetic process" and "metabolic process") and pathways (e.g., "oxidative phosphorylation") were identified. A lncRNA-mRNA co-expression network was constructed from 42 DE lncRNAs and 217 DE mRNAs. Twelve lncRNAs were predicted to have cis-regulated target genes. The microarray analysis results were validated by qRT-PCR using 5 randomly selected lncRNAs and 13 mRNAs. The IHC results revealed that both LOXL2 and FPK-1 exhibited higher protein expression levels in proliferating IH than in involuting IH. Moreover, inhibition of PFK-1 could suppress hemangioma-derived endothelial cell proliferation and migration, induce cell arrest, and reduce glucose uptake and lactate and ATP production.

CONCLUSIONS

The findings suggest that the identified DE lncRNAs and mRNAs may be associated with the pathogenesis of IH. The data presented herein can improve our understanding of IH development and provide direction for further studies investigating the mechanism underlying IH.

YAP promotes ocular neovascularization by modifying PFKFB3-driven endothelial glycolysis

Ocular neovascularization is the leading cause of vision impairment in a variety of ocular diseases, such as age-related macular degeneration and retinopathy of prematurity. Emerging studies have suggested that the yes-associated protein (YAP), a downstream effector of the Hippo pathway, is involved in the pathological angiogenesis, but the mechanism are largely unknown. Here, we demonstrated that hypoxic treatment triggered YAP expression and nuclear translocation in human umbilical vein endothelial cells (HUVECs). YAP acted as a transcriptional co-activator working together with transcriptional enhancer activator domain 1 (TEAD1) to binds the promoter of the key glycolytic regulator 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase3 (PFKFB3), and thereby increases PFKFB3 expression. Moreover, silencing of YAP inhibited glycolysis as well as proliferation, migration, sprouting and tube formation of HUVECs under hypoxia, all of which could be reversed by enforced expression of PFKFB3. Finally, our animal study also showed that intravitreal injection of small interfering RNA of YAP or PFKFB3 dramatically suppressed the neovascular growth in mouse models of choroidal neovascularization and oxygen-induced retinopathy. These findings provide new insights into a previously unrecognized effect of YAP on endothelial glycolysis and highlight the potential of targeting YAP/PFKFB3 axis in the treatment of ocular neovascularization.

Lipid Metabolism and Tumor Antigen Presentation

Tumors always evade immune surveillance and block T cell activation in a poorly immunogenic and immunosuppressive environment. Cancer cells and immune cells exhibit metabolic reprogramming in the tumor microenvironment (TME), which intimately links immune cell function and edits tumor immunology. In addition to glucose metabolism, amino acid and lipid metabolism also provide the materials for biological processes crucial in cancer biology and pathology. Furthermore, lipid metabolism is synergistically or negatively involved in the interactions between tumors and the microenvironment and contributes to the regulation of immune cells. Antigen processing and presentation as the initiation of adaptive immune response play a critical role in antitumor immunity. Therefore, a relationship exists between antigen-presenting cells and lipid metabolism in TME. This chapter introduces the updated understandings of lipid metabolism of tumor antigen-presenting cells and describes new directions in the manipulation of immune responses for cancer treatment.

Exosomes secreted from mesenchymal stem cells mediate the regeneration of endothelial cells treated with rapamycin by delivering pro-angiogenic microRNAs

Delayed endothelial healing after drug eluting stent (DES) implantation is a critical clinical problem in treatment of coronary artery diseases. Exosomes exhibit proangiogenic potential in a variety of ischemic diseases. However, the association of exosomes with endothelial regeneration after DES implantation has been rarely reported. In this study, we aimed to investigate the therapeutic effects of mesenchymal stem cell (MSC)-derived exosomes on endothelial cells treated with rapamycin and explore the potential mechanisms of MSC-derived exosomes in promoting endothelial regeneration. Exosomes were isolated from MSCs by ultracentrifugation and identified by transmission electron microscopy, nanoparticle tracking analysis, and Western blot assay. The in vitro effects of MSC-derived exosomes on the proliferation and migration of endothelial cells treated with rapamycin were evaluated by integrated experiment, cell counting kit-8, scratch, tube formation, and transwell assays. And the apoptosis of rapamycin-induced endothelial cells loaded with MSC-derived exosomes was detected using TUNEL and Annexin-V FITC and PI double-staining assays. The microRNA (miRNA) cargo of MSC-derived exosomes was identified by high-throughput RNA sequencing. Pro-angiogenic miRNAs and key pathways were further characterized. Our results indicated that MSC-derived exosomes could be ingested into umbilical vein endothelial cells (HUVECs) and significantly enhanced cell proliferation rate, migratory and tube-forming capabilities in vitro. MSC-derived exosomes also inhibited the apoptosis of HUVECs induced by rapamycin. A distinct class of exosomal miRNAs was further identified, including six miRNAs tightly related to neovasculogenesis. Silencing the expression of exosomal miRNA-21-5p and let-7c-5p attenuated the pro-proliferative and pro-migratory capacity of MSC-derived exosomes. Moreover, functional enrichment analysis indicated that metabolic pathways might contribute to reendothelialization. This study highlights a proregenerative effect of MSC-derived exosomes in vitro, which may be partly explained by the delivery of pro-angiogenic miRNAs to endothelial cells.

Flow-mediated outward arterial remodeling in aging

The present review focuses on the effect of aging on flow-mediated outward remodeling (FMR) via alterations in estrogen metabolism, oxidative stress and inflammation. In ischemic disorders, the ability of the vasculature to adapt or remodel determines the quality of the recovery. FMR, which has a key role in revascularization, is a complex phenomenon that recruits endothelial and smooth muscle cells as well as the immune system. FMR becomes progressively less with age as a result of an increase in inflammation and oxidative stress, in part of mitochondrial origin. The alteration in FMR is greater in older individuals with risk factors and thus the therapy cannot merely amount to exercise with or without a mild vasodilating drug. Interestingly, the reduction in FMR occurs later in females. Estrogen and its alpha receptor (ERα) play a key role in FMR through the control of dilatory pathways including the angiotensin II type 2 receptor, thus providing possible tools to activate FMR in older subjects although only experimental data is available. Indeed, the main issue is the reversibility of the vascular damage induced over time, and to date promoting prevention and limiting exposure to the risk factors remain the best options in this regard.

Inhibition of glycolytic activator PFKFB3 suppresses tumor growth and induces tumor vessel normalization in hepatocellular carcinoma

Glycolysis emerges as a new therapeutic target for malignancies. The inhibition of glycolytic activator, PFKFB3, repairs tumor endothelial cell function, and normalizing the tumor microenvironment. We aimed to investigate the significance of PFKFB3 in HCC, and the effects of the PFKFB3 inhibitor, PFK15, in HCC tumor cells and tumor endothelial cells. Double immunofluorescent staining of PFKFB3 and CD31 in HCC tissues revealed that high PFKFB3 expression in both tumor cells and tumor endothelial cells was significantly correlated with poor prognosis. Multivariate analysis identified PFKFB3 expression as an independent prognostic factor. PFK15 suppressed proliferation of HCC cell line and tumor endothelial cells in vitro. In a subcutaneous tumor model of the HCC cell line with tumor endothelial cells, PFK15 suppressed tumor growth and induced apoptosis. Moreover, PFK15 treatment induced tumor vessel normalization, decreasing vessel diameter with pericyte attachment and improving vessel perfusion. High PFKFB3 expression in both tumor cells and tumor endothelial cells was identified as a novel prognostic marker in HCC. Targeting PFKFB3 via PFK15 might be a promising strategy for suppressing tumor growth and inducing tumor vessel normalization.

Single-cell gene profiling and lineage tracing analyses revealed novel mechanisms of endothelial repair by progenitors

Stem/progenitor cells (SPCs) have been implicated to participate in vascular repair. However, the exact role of SPCs in endothelial repair of large vessels still remains controversial. This study aimed to delineate the cellular heterogeneity and possible functional role of endogenous vascular SPCs in large vessels. Using single-cell RNA-sequencing (scRNA-seq) and genetic lineage tracing mouse models, we uncovered the cellular heterogeneity of SPCs, i.e., c-Kit+ cells in the mouse aorta, and found that endogenous c-Kit+ cells acquire endothelial cell fate in the aorta under both physiological and pathological conditions. While c-Kit+ cells contribute to aortic endothelial turnover in the atheroprone regions during homeostasis, recipient c-Kit+ cells of nonbone marrow source replace both luminal and microvessel endothelial cells in transplant arteriosclerosis. Single-cell pseudotime analysis of scRNA-seq data and in vitro cell experiments suggest that vascular SPCs display endothelial differentiation potential and undergo metabolic reprogramming during cell differentiation, in which AKT/mTOR-dependent glycolysis is critical for endothelial gene expression. These findings demonstrate a critical role for c-Kit lineage cells in aortic endothelial turnover and replacement, and may provide insights into therapeutic strategies for vascular diseases.

BDNF corrects NLRP3 inflammasome-induced pyroptosis and glucose metabolism reprogramming through KLF2/HK1 pathway in vascular endothelial cells

NLRP3 inflammasome-mediated vascular EC pyroptosis is a key event in the pathogenesis of atherosclerosis. Dysregulation of glucose metabolism is involved in EC dysfunction. Although BDNF plays a protective role in vascular endothelium physiological activity, the mechanisms underlying this activity are not yet clear. In this study, we investigated the role of BDNF in NLRP3 inflammasome-mediated EC pyroptosis and its associated reprogramming of glucose metabolism. HUVECs were treated with human rBDNF under ox-LDL stimulation. rBDNF alleviated ox-LDL-induced NLRP3 inflammasome formation and HUVEC pyroptosis, as evaluated by NLRP3, caspase1-p10, interleukin-18, and interleukin-1β protein levels, co-localization of NLRP3 and apoptosis-associated speck-like protein, and lactate dehydrogenase release. These effects were prevented by tropomyosin receptor kinase B inhibition and KLF2 silencing. The hyper-activation of glycolysis induced by ox-LDL-induced was mitigated by rBDNF via KLF2 as assessed by glucose uptake, lactate production, and extracellular acidification rate. In addition, the BDNF/KLF2 pathway preserved the mitochondrial membrane potential, intracellular reactive oxygen species generation, electron transport chain processing, oxygen consumption rate, and adenosine triphosphate production. Furthermore, KLF2 interacted with HK1 and HK1 overexpression evoked NLRP3 inflammasome formation. At the clinical level, plasma BDNF and lactate levels were measured in 274 patients who underwent computed tomography and coronary angiography for CAD diagnosis. Patients with CAD had lower BDNF and increased lactate levels than those without CAD. In 94 patients with CAD, circulating BDNF levels were inversely associated with lactate levels. In the receiver operating characteristic analysis of CAD, the areas under the curves for 1/BDNF, lactate, and 1/BDNF+lactate were 0.707, 0.702, and 0.753 respectively. These results indicate that BDNF and lactate are linked in atherosclerotic patients, and BDNF inhibits ox-LDL induced NLRP3 inflammasome formation and pyroptosis in HUVECs via KLF2/HK1-mediated glucose metabolism modulation and mitochondrial homeostasis preservation.

BTX-A Promotes Expression of Angiogenesis-Associated Genes in Human Umbilical Vein Endothelial Cells

Raynaud's phenomenon (RP) is an episodic vasospasm of the peripheral arteries caused by an exaggerated reaction to cold temperature or emotional stress. Restoring the angiogenesis capability of the acral lesional skin is a critical strategy to treat RP. Local injection of botulinum toxin-A (BTX-A) has also been reported for treatment of RP. However, since the exact mechanisms of BTX-A action are still unclear, its administration for treatment of RP is not widely used. In the present study, BTX-A was found to promote angiogenesis and relieve RP in the patient. To elucidate its mechanisms against angiogenesis, BTX-A was used to treat human umbilical vein endothelial cells (HUVECs), one of the most popular in vitro models of angiogenesis, and RNA sequencing was used to investigate differentially expressed genes. A total of 413 genes were upregulated, and 1634 were downregulated, with fold-changes >2.0 in HUVECs treated with BTX-A. Gene ontology annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed BTX-A affected expression of angiogenesis-associated, angiogenesis-associated signaling pathway-related, metabolic pathway, and epigenetic regulation-related genes. These results demonstrate potential biomarkers of BTX-A action, thereby providing potential therapeutic mechanism(s) by which BTX-A relieves RP symptoms.

Mapping endothelial-cell diversity in cerebral cavernous malformations at single-cell resolution

Cerebral cavernous malformation (CCM) is a rare neurovascular disease that is characterized by enlarged and irregular blood vessels that often lead to cerebral hemorrhage. Loss-of-function mutations to any of three genes results in CCM lesion formation; namely, KRIT1, CCM2, and PDCD10 (CCM3). Here, we report for the first time in-depth single-cell RNA sequencing, combined with spatial transcriptomics and immunohistochemistry, to comprehensively characterize subclasses of brain endothelial cells (ECs) under both normal conditions and after deletion of Pdcd10 (Ccm3) in a mouse model of CCM. Integrated single-cell analysis identifies arterial ECs as refractory to CCM transformation. Conversely, a subset of angiogenic venous capillary ECs and respective resident endothelial progenitors appear to be at the origin of CCM lesions. These data are relevant for the understanding of the plasticity of the brain vascular system and provide novel insights into the molecular basis of CCM disease at the single cell level.

3D printed in vitro tumor tissue model of colorectal cancer

Rationale: The tumor microenvironment (TME) determines tumor progression and affects clinical therapy. Its basic components include cancer-associated fibroblasts (CAFs) and tumor-associated endothelial cells (TECs), both of which constitute the tumor matrix and microvascular network. The ability to simulate interactions between cells and extracellular matrix in a TME in vitro can assist the elucidation of cancer growth and evaluate the efficiency of therapies. Methods: In the present study, an in vitro 3D model of tumor tissue that mimicked in vivo cell physiological function was developed using tumor-associated stromal cells. Colorectal cancer cells, CAFs, and TECs were co-cultured on 3D-printed scaffolds so as to constitute an extracellular matrix (ECM) that allowed cell processes such as adhesion, stemness, proliferation, and vascularization to take place. Normal stromal cells were activated and reprogrammed into tumor-related stromal cells to construct a TME of tumor tissues. Results: The activated stromal cells overexpressed a variety of tumor-related markers and remodeled the ECM. Furthermore, the metabolic signals and malignant transformation of the in vitro 3D tumor tissue was substantially similar to that observed in tumors in vivo. Conclusions: The 3D tumor tissue exhibited physiological activity with high drug resistance. The model is suitable for research studies of tumor biology and the development of personalized treatments for cancer.

Exosome-mediated metabolic reprogramming: the emerging role in tumor microenvironment remodeling and its influence on cancer progression

Metabolic reprogramming is reported to be one of the hallmarks of cancer, which is an adaptive mechanism by which fast-growing cancer cells adapt to their increasing energy demands. Recently, extracellular vesicles (EVs) known as exosomes have been recognized as crucial signaling mediators in regulating the tumor microenvironment (TME). Meanwhile, the TME is a highly heterogeneous ecosystem incorporating cancer cells, fibroblasts, adipocytes, endothelial cells, mesenchymal stem cells, and extracellular matrix. Accumulated evidence indicates that exosomes may transfer biologically functional molecules to the recipient cells, which facilitate cancer progression, angiogenesis, metastasis, drug resistance, and immunosuppression by reprogramming the metabolism of cancer cells and their surrounding stromal cells. In this review, we present the role of exosomes in the TME and the underlying mechanism of how exosomes exacerbate tumor development through metabolic reprogramming. In addition, we will also discuss the potential role of exosomes targeting metabolic process as biomarkers for tumor diagnosis and prognosis, and exosomes-mediated metabolic reprogramming as potential targets for cancer therapy. Furthermore, a better understanding of the link between exosomes and metabolic reprogramming, and their impact on cancer progression, would provide novel insights for cancer prevention and treatment in the future.

Tubulin carboxypeptidase activity of vasohibin-1 inhibits angiogenesis by interfering with endocytosis and trafficking of pro-angiogenic factor receptors

Receptor endocytosis is crucial for integrating extracellular stimuli of pro-angiogenic factors, including vascular endothelial growth factor (VEGF), into the cell via signal transduction. VEGF not only triggers various angiogenic events including endothelial cell (EC) migration, but also induces the expression of negative regulators of angiogenesis, including vasohibin-1 (VASH1). While we have previously reported that VASH1 inhibits angiogenesis in vitro and in vivo, its mode of action on EC behavior remains elusive. Recently VASH1 was shown to have tubulin carboxypeptidase (TCP) activity, mediating the post-translational modification of microtubules (MTs) by detyrosination of α-tubulin within cells. However, the role of VASH1 TCP activity in angiogenesis has not yet been clarified. Here, we showed that VASH1 detyrosinated α-tubulin in ECs and suppressed in vitro and in vivo angiogenesis. In cultured ECs, VASH1 impaired endocytosis and trafficking of VEGF receptor 2 (VEGFR2), which resulted in the decreased signal transduction and EC migration. These effects of VASH1 could be restored by tubulin tyrosine ligase (TTL) in ECs, suggesting that detyrosination of α-tubulin negatively regulates angiogenesis. Furthermore, we found that detyrosinated tubulin-rich MTs were not adequate as trafficking rails for VEGFR2 endocytosis. Consistent with these results, inhibition of TCP activity of VASH1 led to the inhibition of VASH1-mediated suppression of VEGF-induced signals, EC migration, and in vivo angiogenesis. Our results indicate a novel mechanism of VASH1-mediated inhibition of pro-angiogenic factor receptor trafficking via modification of MTs.

Identification of bioactive anti-angiogenic components targeting tumor endothelial cells in Shenmai injection using multidimensional pharmacokinetics

Shenmai injection (SMI) is a well-defined herbal preparation that is widely and clinically used as an adjuvant therapy for cancer. Previously, we found that SMI synergistically enhanced the activity of chemotherapy on colorectal cancer by promoting the distribution of drugs in xenograft tumors. However, the underlying mechanisms and bioactive constituents remained unknown. In the present work, the regulatory effects of SMI on tumor vasculature were determined, and the potential anti-angiogenic components targeting tumor endothelial cells (TECs) were identified. Multidimensional pharmacokinetic profiles of ginsenosides in plasma, subcutaneous tumors, and TECs were investigated. The results showed that the concentrations of protopanaxadiol-type (PPD) ginsenosides (Rb1, Rb2/Rb3, Rc, and Rd) in both plasma and tumors, were higher than those of protopanaxatriol-type (Rg1 and Re) and oleanane-type (Ro) ginsenosides. Among PPD-type ginsenosides, Rd exhibited the greatest concentrations in tumors and TECs after repeated injection. In vivo bioactivity results showed that Rd suppressed neovascularization in tumors, normalized the structure of tumor vessels, and improved the anti-tumor effect of 5-fluorouracil (5FU) in xenograft mice. Furthermore, Rd inhibited the migration and tube formation capacity of endothelial cells in vitro. In conclusion, Rd may be an important active form to exert the anti-angiogenic effect on tumor after SMI treatment.

Lipid-mediated regulation of the cancer-immune crosstalk

Besides acting as principle cellular building blocks and energy reservoirs, lipids also carry important signals associated with many fundamental cell biological processes, such as proliferation, differentiation, migration, stress responses and cell demise. Hyperactive lipid metabolism is closely associated with cancer progression and unfavorable outcomes. The underlying mechanisms are being gradually deciphered. In this review, we aim to summarize recent advances on how reprogrammed lipid metabolism and accompanying signaling cascades directly modulate cancer cells, as well as influencing stromal cells and immune cells within the tumor microenvironment. For future studies, special attention should be paid to lipid-mediated crosstalk among cancer cells, their neighboring stromal cells, and immune cells, plus how these multi-level communications determine anti-tumor immunity and bring novel immunotherapeutic opportunities.

Metabolism of vascular smooth muscle cells in vascular diseases

Vascular smooth muscle cells (VSMCs) are the fundamental component of the medial layer of arteries and are essential for arterial physiology and pathology. It is becoming increasingly clear that VSMCs can alter their metabolism to fulfill the bioenergetic and biosynthetic requirements. During vascular injury, VSMCs switch from a quiescent "contractile" phenotype to a highly migratory and proliferative "synthetic" phenotype. Recent studies have found that the phenotype switching of VSMCs is driven by a metabolic switch. Metabolic pathways, including aerobic glycolysis, fatty acid oxidation, and amino acid metabolism, have distinct, indispensable roles in normal and dysfunctional vasculature. VSMCs metabolism is also related to the metabolism of endothelial cells. In the present review, we present a brief overview of VSMCs metabolism and how it regulates the progression of several vascular diseases, including atherosclerosis, systemic hypertension, diabetes, pulmonary hypertension, vascular calcification, and aneurysms, and the effect of the risk factors for vascular disease (aging, cigarette smoking, and excessive alcohol drinking) on VSMC metabolism to clarify the role of VSMCs metabolism in the key pathological process.

Selective inhibition of mTORC1 in tumor vessels increases antitumor immunity

A tumor blood vessel is a key regulator of tissue perfusion, immune cell trafficking, cancer metastasis, and therapeutic responsiveness. mTORC1 is a signaling node downstream of multiple angiogenic factors in the endothelium. However, mTORC1 inhibitors have limited efficacy in most solid tumors, in part due to inhibition of immune function at high doses used in oncology patients and compensatory PI3K signaling triggered by mTORC1 inhibition in tumor cells. Here we show that low-dose RAD001/everolimus, an mTORC1 inhibitor, selectively targets mTORC1 signaling in endothelial cells (ECs) without affecting tumor cells or immune cells, resulting in tumor vessel normalization and increased antitumor immunity. Notably, this phenotype was recapitulated upon targeted inducible gene ablation of the mTORC1 component Raptor in tumor ECs (RaptorECKO). Tumors grown in RaptorECKO mice displayed a robust increase in tumor-infiltrating lymphocytes due to GM-CSF-mediated activation of CD103+ dendritic cells and displayed decreased tumor growth and metastasis. GM-CSF neutralization restored tumor growth and metastasis, as did T cell depletion. Importantly, analyses of human tumor data sets support our animal studies. Collectively, these findings demonstrate that endothelial mTORC1 is an actionable target for tumor vessel normalization, which could be leveraged to enhance antitumor immune therapies.

Flavin adenine dinucleotide ameliorates hypertensive vascular remodeling via activating short chain acyl-CoA dehydrogenase

AIMS

Flavin adenine dinucleotide (FAD), participates in fatty acid β oxidation as a cofactor, which has been confirmed to enhance SCAD activity and expression. However, the role of FAD on hypertensive vascular remodeling is unclear. In this study, we investigated the underlying mechanisms of FAD on vascular remodeling and endothelial homeostasis.

MAIN METHODS

Morphological examination of vascular remodeling were analyzed with hematoxylin and eosin (HE) staining, Verhoeff's Van Gieson (EVG) staing, Dihydroethidium (DHE) staining and Sirius red staining. HUVECs apoptotic rate was detected by flow cytometry and HUVECs reactive oxygen species (ROS) was detected by DHE-probe. Enzymatic reactions were used to detect SCAD enzyme activity. The protein level was detected by Western Blots, the mRNA level was detected by quantitative real-time PCR.

KEY FINDINGS

In vivo experiments, FAD significantly decreased blood pressure and ameliorated vascular remodeling by increasing SCAD expression, Nitric Oxide (NO) production and reducing ROS production. In vitro experiments, FAD protected against the tBHP induced injury in HUVEC, by increasing the activity of SCAD, increasing the elimination of free fatty acid (FFA), scavenging ROS, reducing apoptotic rate, thereby improving endothelial cell function.

SIGNIFICANCE

FAD has a new possibility for preventing and treating hypertensive vascular remodeling.

Mitochondrial respiration controls neoangiogenesis during wound healing and tumour growth

The vasculature represents a highly plastic compartment, capable of switching from a quiescent to an active proliferative state during angiogenesis. Metabolic reprogramming in endothelial cells (ECs) thereby is crucial to cover the increasing cellular energy demand under growth conditions. Here we assess the impact of mitochondrial bioenergetics on neovascularisation, by deleting cox10 gene encoding an assembly factor of cytochrome c oxidase (COX) specifically in mouse ECs, providing a model for vasculature-restricted respiratory deficiency. We show that EC-specific cox10 ablation results in deficient vascular development causing embryonic lethality. In adult mice induction of EC-specific cox10 gene deletion produces no overt phenotype. However, the angiogenic capacity of COX-deficient ECs is severely compromised under energetically demanding conditions, as revealed by significantly delayed wound-healing and impaired tumour growth. We provide genetic evidence for a requirement of mitochondrial respiration in vascular endothelial cells for neoangiogenesis during development, tissue repair and cancer.

During angiogenesis the vasculature switches from a quiescent to a proliferative state. Here the authors show that mitochondrial respiration in endothelial cells controls angiogenesis during development, tumour growth and tissue repair.