The PTEN/PI3K pathway governs normal vascular development and tumor angiogenesis

DNA aptamer-conjugated lipid nanoparticle for targeted PTEN mRNA delivery to prostate cancer cells

The use of messenger RNA (mRNA) as a cancer vaccine and gene therapy requires targeted vehicle delivery to the site of disease. Here, we designed a mRNA-encapsulating lipid nanoparticle (LNP) conjugated with anti-programmed death-ligand 1 (PD-L1) DNA aptamer that delivers mRNA encoding a tumor suppressor gene, namely phosphatase and tensin homolog (PTEN), to castration-resistant prostate cancer (CRPC) cells expressing PD-L1 on the cell surface. The DNA aptamer-conjugated LNP-based mRNA delivery system (Apt-LNP[PTEN mRNA]) mediated efficient mRNA delivery and transfection in CRPC cells than LNPs without targeting ligands. Cancer-targeted PTEN mRNA delivery using Apt-LNPs achieved significantly higher PTEN expression via aptamer-mediated endocytosis in target cancer cells compared with non-targeted LNP delivery, resulting in significant downregulation of AKT phosphorylation. This enhanced PI3K/AKT pathway regulation, and in turn reduced cell migration after two days along with a 70 % decrease in cell viability, leading to effective apoptotic cell death. In a CRPC xenograft model, Apt-LNP[PTEN mRNA] led to an approximate 60 % reduction in tumor growth, which was attributable to the effective PTEN restoration and PI3K/AKT signaling pathway regulation. PTEN expression was significantly enhanced in CRPC tumor tissues, which abolished cancer cell tumorigenicity. These findings demonstrated the potential of Apt-LNPs for targeted mRNA delivery to cancer cells, thus providing a promising tool for targeted mRNA delivery to a range of cancers and tissues using a conventional LNP systems.

Shear stress and pathophysiological PI3K involvement in vascular malformations

Molecular characterization of vascular anomalies has revealed that affected endothelial cells (ECs) harbor gain-of-function (GOF) mutations in the gene encoding the catalytic α subunit of PI3Kα (PIK3CA). These PIK3CA mutations are known to cause solid cancers when occurring in other tissues. PIK3CA-related vascular anomalies, or "PIKopathies," range from simple, i.e., restricted to a particular form of malformation, to complex, i.e., presenting with a range of hyperplasia phenotypes, including the PIK3CA-related overgrowth spectrum. Interestingly, development of PIKopathies is affected by fluid shear stress (FSS), a physiological stimulus caused by blood or lymph flow. These findings implicate PI3K in mediating physiological EC responses to FSS conditions characteristic of lymphatic and capillary vessel beds. Consistent with this hypothesis, increased PI3K signaling also contributes to cerebral cavernous malformations, a vascular disorder that affects low-perfused brain venous capillaries. Because the GOF activity of PI3K and its signaling partners are excellent drug targets, understanding PIK3CA's role in the development of vascular anomalies may inform therapeutic strategies to normalize EC responses in the diseased state. This Review focuses on PIK3CA's role in mediating EC responses to FSS and discusses current understanding of PIK3CA dysregulation in a range of vascular anomalies that particularly affect low-perfused regions of the vasculature. We also discuss recent surprising findings linking increased PI3K signaling to fast-flow arteriovenous malformations in hereditary hemorrhagic telangiectasias.

Review: The PI3K-AKT-mTOR signal transduction pathway in canine cancer

Tumors in dogs and humans share many similar molecular and genetic features, incentivizing a better understanding of canine neoplasms not only for the purpose of treating companion animals, but also to facilitate research of spontaneously developing tumors with similar biologic behavior and treatment approaches in an immunologically competent animal model. Multiple tumor types of both species have similar dysregulation of signal transduction through phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB; AKT), and mechanistic target of rapamycin (mTOR), collectively known as the PI3K-AKT-mTOR pathway. This review aims to delineate the pertinent aspects of the PI3K-AKT-mTOR signaling pathway in health and in tumor development. It will then present a synopsis of current understanding of PI3K-AKT-mTOR signaling in important canine cancers and advancements in targeted inhibitors of this pathway.

Generation of Slco1a4-CreERT2-tdTomato Knock-in Mice for Specific Cerebrovascular Endothelial Cell Targeting

The cerebrovascular endothelial cells with distinct characteristics line cerebrovascular blood vessels and are the fundamental structure of the blood-brain barrier, which is important for the development and homeostatic maintenance of the central nervous system. Cre-LoxP system-based spatial gene manipulation in mice is critical for investigating the physiological functions of key factors or signaling pathways in cerebrovascular endothelial cells. However, there is a lack of Cre recombinase mouse lines that specifically target cerebrovascular endothelial cells. Here, using a publicly available single-cell RNAseq database, we screened the solute carrier organic anion transporter family member 1a4 (Slco1a4) as a candidate marker of cerebrovascular endothelial cells. Then, we generated an inducible Cre mouse line in which a CreERT2-T2A-tdTomato cassette was placed after the initiation codon ATG of the Slco1a4 locus. We found that tdTomato, which can indicate the endogenous Slco1a4 expression, was expressed in almost all cerebrovascular endothelial cells but not in any other non-endothelial cell types in the brain, including neurons, astrocytes, oligodendrocytes, pericytes, smooth muscle cells, and microglial cells, as well as in other organs. Consistently, when crossing the ROSA26LSL-EYFP Cre reporter mouse, EYFP also specifically labeled almost all cerebrovascular endothelial cells upon tamoxifen induction. Overall, we generated a new inducible Cre line that specifically targets cerebrovascular endothelial cells.

Endothelial plasticity across PTEN and Hippo pathways: A complex hormetic rheostat modulated by extracellular vesicles

Vascularization is a multifactorial and spatiotemporally regulated process, essential for cell and tissue survival. Vascular alterations have repercussions on the development and progression of diseases such as cancer, cardiovascular diseases, and diabetes, which are the leading causes of death worldwide. Additionally, vascularization continues to be a challenge for tissue engineering and regenerative medicine. Hence, vascularization is the center of interest for physiology, pathophysiology, and therapeutic processes. Within vascularization, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and Hippo signaling have pivotal roles in the development and homeostasis of the vascular system. Their suppression is related to several pathologies, including developmental defects and cancer. Non-coding RNAs (ncRNAs) are among the regulators of PTEN and/or Hippo pathways during development and disease. The purpose of this paper is to review and discuss the mechanisms by which exosome-derived ncRNAs modulate endothelial cell plasticity during physiological and pathological angiogenesis, through the regulation of PTEN and Hippo pathways, aiming to establish new perspectives on cellular communication during tumoral and regenerative vascularization.

PI(4,5)P2-dependent regulation of endothelial tip cell specification contributes to angiogenesis

Dynamic positioning of endothelial tip and stalk cells, via the interplay between VEGFR2 and NOTCH signaling, is essential for angiogenesis. VEGFR2 activates PI3K, which phosphorylates PI(4,5)P₂ to PI(3,4,5)P₃, activating AKT; however, PI3K/AKT does not direct tip cell specification. We report that PI(4,5)P₂ hydrolysis by the phosphoinositide-5-phosphatase, INPP5K, contributes to angiogenesis. INPP5K ablation disrupted tip cell specification and impaired embryonic angiogenesis associated with enhanced DLL4/NOTCH signaling. INPP5K degraded a pool of PI(4,5)P₂ generated by PIP5K1C phosphorylation of PI(4)P in endothelial cells. INPP5K ablation increased PI(4,5)P₂, thereby releasing β-catenin from the plasma membrane, and concurrently increased PI(3,4,5)P₃-dependent AKT activation, conditions that licensed DLL4/NOTCH transcription. Suppression of PI(4,5)P₂ in INPP5K-siRNA cells by PIP5K1C-siRNA, restored β-catenin membrane localization and normalized AKT signaling. Pharmacological NOTCH or AKT inhibition in vivo or genetic β-catenin attenuation rescued angiogenesis defects in INPP5K-null mice. Therefore, PI(4,5)P₂ is critical for β-catenin/DLL4/NOTCH signaling, which governs tip cell specification during angiogenesis.

TWEAK and TNFα, Both TNF Ligand Family Members and Multiple Sclerosis-Related Cytokines, Induce Distinct Gene Response in Human Brain Microvascular Endothelial Cells

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) is a member of the TNF ligand family involved in various diseases including brain inflammatory pathologies such as multiple sclerosis. It has been demonstrated that TWEAK can induce cerebrovascular permeability in an in vitro model of the blood-brain barrier. The molecular mechanisms playing a role in TWEAK versus TNFα signaling on cerebral microvascular endothelial cells are not well defined. Therefore, we aimed to identify gene expression changes in cultures of human brain microvascular endothelial cells (hCMEC/D3) to address changes initiated by TWEAK exposure. Taken together, our studies highlighted that gene involved in leukocyte extravasation, notably claudin-5, were differentially modulated by TWEAK and TNFα. We identified differential gene expression of hCMEC/D3 cells at three timepoints following TWEAK versus TNFα stimulation and also found distinct modulations of several canonical pathways including the actin cytoskeleton, vascular endothelial growth factor (VEGF), Rho family GTPases, and phosphatase and tensin homolog (PTEN) pathways. To our knowledge, this is the first study to interrogate and compare the effects of TWEAK versus TNFα on gene expression in brain microvascular endothelial cells.

Combining radiation with PI3K isoform-selective inhibitor administration increases radiosensitivity and suppresses tumor growth in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a malignant lung tumor with a dismal prognosis. The activation of the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway is common in many tumor types including NSCLC, which results in radioresistance and changes in the tumor microenvironment. Although pan-PI3K inhibitors have been tested in clinical trials to overcome radioresistance, concerns regarding their excessive side effects led to the consideration of selective inhibition of PI3K isoforms. In this study, we assessed whether combining radiation with the administration of the PI3K isoform-selective inhibitors reduces radioresistance and tumor growth in NSCLC. Inhibition of the PI3K/AKT pathway enhanced radiosensitivity substantially, and PI3K-α inhibitor showed superior radiosensitizing effect similar to PI3K pan-inhibitor, both in vitro and in vivo. Additionally, a significant increase in DNA double-strand breaks (DSB) and a decrease in migration ability were observed. Our study revealed that combining radiation and the PI3K-α isoform improved radiosensitivity that resulted in a significant delay in tumor growth and improved survival rate.

Phosphatase and Tensin Homology Deleted on Chromosome 10 Inhibitors Promote Neural Stem Cell Proliferation and Differentiation

Phosphatase and tensin homology deleted on chromosome 10 (PTEN) is a tumor suppressor gene. Its encoded protein has phosphatase and lipid phosphatase activities, which regulate the growth, differentiation, migration, and apoptosis of cells. The catalytic activity of PTEN is crucial for controlling cell growth under physiological and pathological conditions. It not only affects the survival and proliferation of tumor cells, but also inhibits a variety of cell regeneration processes. The use of PTEN inhibitors is being explored as a potentially beneficial therapeutic intervention for the repair of injuries to the central nervous system. PTEN influences the proliferation and differentiation of NSCs by regulating the expression and phosphorylation of downstream molecular protein kinase B (Akt) and the mammalian target of rapamycin (mTOR). However, the role of PTEN inhibitors in the Akt/mTOR signaling pathway in NSC proliferation and differentiation is unclear. Dipotassium bisperoxo (picolinoto) oxovanadate (V) [bpv(pic)] is a biologically active vanadium compound that blocks PTEN dephosphorylation and suppresses its activity, and has been used as a PTEN lipid phosphatase inhibitor. Here, bpv(pic) intervention was found to significantly increase the number of rat NSCs, as determined by bromodeoxyuridine staining and the cell counting kit-8, and to increase the percentage of neurons undergoing differentiation, as shown by immunofluorescence staining. Bpv(pic) intervention also significantly increased PTEN and mTOR expression, as shown by real-time PCR analysis and western blotting. In conclusion, PTEN inhibitor bpv(pic) promotes the proliferation and differentiation of NSCs into neurons.

Cancer-Induced Metabolic Rewiring of Tumor Endothelial Cells

Simple Summary

Angiogenesis, the formation of new blood vessels from preexisting ones, is a complex and demanding biological process that plays an important role in physiological, as well as pathological conditions, including cancer. During tumor growth, the induction of angiogenesis allows tumor cells to grow, invade, and metastasize. Recent evidence supports endothelial cell metabolism as a critical regulator of angiogenesis. However, whether and how tumor endothelial cells rewire their metabolism in cancer remains elusive. In this review, we discussed the metabolic signatures of tumor endothelial cells and their symbiotic, competitive, and mechanical metabolic interactions with tumor cells. We also discussed the recent works that may provide a rationale for attractive metabolic targets and strategies for developing specific therapies against tumor angiogenesis.

Abstract

Cancer is a leading cause of death worldwide. If left untreated, tumors tend to grow and spread uncontrolled until the patient dies. To support this growth, cancer cells need large amounts of nutrients and growth factors that are supplied and distributed to the tumor tissue by the vascular system. The aberrant tumor vasculature shows deep morphological, molecular, and metabolic differences compared to the blood vessels belonging to the non-malignant tissues (also referred as normal). A better understanding of the metabolic mechanisms driving the differences between normal and tumor vasculature will allow the designing of new drugs with a higher specificity of action and fewer side effects to target tumors and improve a patient’s life expectancy. In this review, we aim to summarize the main features of tumor endothelial cells (TECs) and shed light on the critical metabolic pathways that characterize these cells. A better understanding of such mechanisms will help to design innovative therapeutic strategies in healthy and diseased angiogenesis.

Deletion of MicroRNA-21 Impairs Neovascularization Following Limb Ischemia: From Bedside to Bench

With an increasing prevalence, peripheral arterial disease (PAD), cause by atherosclerosis is a new threat to public health beyond coronary artery disease and involves aberrant vascular endothelial cell proliferation and angiogenesis. The degree of vascular remodeling is influenced by the processes described. MicroRNA-21 (miR-21) has been found to play a critical role in cellular functions, including angiogenesis. Nevertheless, the effect of miR-21 on endothelial cells in response to hypoxia is largely unknown. Using wild-type C57BL/6J and miR-21^–/– mice, we compared the capability of angiogenesis in response to hindlimb hypoxic/ischemia. In an in vitro study, we further studied whether overexpression of miR-21 mitigates hypoxia-induced apoptosis and impaired angiogenesis. Also, we prospectively collected the sera of patients with limb ischemia and followed the clinical information, including major adverse limb events (MALEs). Using laser Doppler perfusion imaging and CD31 staining, compared with miR-21^–/– mice, wild-type mice expressed a significantly higher capability of angiogenesis and less apoptosis following 28 days of hindlimb hypoxic/ischemic surgery. In our in vitro study, after 24 h of hypoxia, proliferation, migration, and tube formation were significantly impaired in cells treated with the miR-21 inhibitor but rescued by the miR-21 mimic. Mechanistically, by suppressing PTEN/PI3K/AKT, miR-21 promoted angiogenesis and suppressed apoptosis in endothelial cells post hypoxia. In patients with limb ischemia, the high expression of circulating miR-21 was associated with less subsequent MALE. Collectively, miR-21 could be a biomarker associated with the endogenous ability of angiogenesis and reflect subsequent MALE in patients. Additionally, abolishing miR-21 impairs angiogenesis and promotes apoptosis post limb ischemia. Further studies are required to elucidate the clinical applications of miR-21.

Formation of a de novo intracranial arteriovenous fistula in a child with PTEN hamartoma tumor syndrome

PURPOSE

Dural arteriovenous fistulae (dAVF) are an uncommon feature of PTEN hamartoma tumor syndrome (PHTS). We report a case of an adolescent male diagnosed with PHTS following the treatment of multiple intracranial dAVF to emphasize the association of vascular anomalies with this disorder and discuss potential implications.

CASE REPORT

An adolescent male presented with bilateral proptosis secondary to intracranial venous hypertension. Workup revealed the presence of a complex intracranial dAVF which was treated with several embolization procedures. Following treatment, a de novo dAVF was identified on surveillance imaging. A genetic workup revealed a pathogenic mutation in PTEN consistent with a diagnosis of PHTS.

CONCLUSIONS

Recognition that PHTS may be associated with dAVF, and potentially delayed spontaneous formation of dAVF, is critically important due to the potential for devastating yet preventable neurologic sequelae.

Discovery of novel selective PI3Kγ inhibitors through combining machine learning-based virtual screening with multiple protein structures and bio-evaluation

Introduction

Phosphoinositide 3-kinase gamma (PI3Kγ) has been regarded as a promising drug target for the treatment of various diseases, and the diverse physiological roles of class I PI3K isoforms (α, β, δ, and γ) highlight the importance of isoform selectivity in the development of PI3Kγ inhibitors. However, the high structural conservation among the PI3K family makes it a big challenge to develop selective PI3Kγ inhibitors.

Objectives

A novel machine learning-based virtual screening with multiple PI3Kγ protein structures was developed to discover novel PI3Kγ inhibitors.

Methods

A large chemical database was screened using the virtual screening model, the top-ranked compounds were then subjected to a series of bio-evaluations, which led to the discovery of JN-KI3. The selective inhibition mechanism of JN-KI3 against PI3Kγ was uncovered by a theoretical study.

Results

49 hits were identified through virtual screening, and the cell-free enzymatic studies found that JN-KI3 selectively inhibited PI3Kγ at a concentration as low as 3,873 nM but had no inhibitory effect on Class IA PI3Ks, leading to the selective cytotoxicity on hematologic cancer cells. Meanwhile, JN-KI3 potently blocked the PI3K signaling, finally led to distinct apoptosis of hematologic cell lines at a low concentration. Lastly, the key residues of PI3Kγ and the structural characteristics of JN-KI3, which both would influence γ isoform-selective inhibition, were highlighted by systematic theoretical studies.

Conclusion

The developed virtual screening model strongly manifests the robustness to find novel PI3Kγ inhibitors. JN-KI3 displays a specific cytotoxicity on hematologic tumor cells, and significantly promotes apoptosis associated with the inhibition of the PI3K signaling, which depicts PI3Kγ as a potential target for the hematologic tumor therapy. The theoretical results reveal that those key residues interacting with JN-KI3 are less common compared to most of the reported PI3Kγ inhibitors, indicating that JN-KI3 has novel structural characteristics as a selective PIK3γ inhibitor.

OUP accepted manuscript

Paediatric intracranial dural arteriovenous shunts have clinical presentations and evolutions, with angiographic characteristics that differ from those described in adults. We report our experience concerning their therapeutic management, emphasizing the relevance of early diagnosis and appropriate treatment for satisfactory neurocognitive development. Using a prospective database, we reviewed the clinical and radiological data of all children with dural arteriovenous shunts managed between 2002 and 2020. Dural shunts were categorized into three types: dural sinus malformations with arteriovenous shunts; infantile dural arteriovenous shunts; and adult-type dural arteriovenous shunts. Therapeutic strategies and outcomes were analysed depending on lesional subtypes. Modified Rankin Scale for the paediatric population was assessed pre-treatment and at last follow-up. Twenty-eight patients [16 girls (57.1%); 12 boys (42.9%)] were included: 17 dural sinus malformation [10 boys (58.8%); seven girls (41.2%)], three infantile shunts [three girls (100%)], eight adult-type shunts [four girls (50%)]; four boys (50%)], with a mean age of 19.2 ± 36.6 months at presentation. Twelve (42.9%) had a modified Rankin Scale score of 0–2, four (14.3%) had a score of 3, three (10.7%) had a score of 4 and eight (28.6%) had a score of 5. Embolization was performed in 22 children [78.6%; 12 girls (54.5%); 10 boys (45.5%)]. Fifteen patients could be cured (68.2%): 11 dural sinus malformations (73.3%), four adult-type lesions (100%) but no infantile shunt. Mean post-treatment follow-up was 39.5 months (max. 139 months): 14 patients (63.6%) presented a modified Rankin Scale score of 0–2 and eight (36.4%) had a score ≥3. In the dural sinus malformation group, the modified Rankin Scale score was improved in 11 patients (73.3%) and unchanged in three (20%). Only one patient with infantile subtype (33.3%) improved clinically. In the adult-subtype group, all children (100%) improved. Of six untreated patients [four girls (66.7%); two boys (33.3%)], four with adult-subtype shunts showed uneventful evolutions, one with dural sinus malformation died, and therapeutic abortion was conducted in an antenatally diagnosed dural sinus malformation. Paediatric dural fistulas comprise different subtypes with variable clinical courses. Proper diagnosis is mandatory for optimal therapeutic strategies within appropriate therapeutic windows.

FGD5 regulates endothelial cell PI3 kinase-β to promote neo-angiogenesis

Angiogenesis is required in embryonic development and tissue repair in the adult. Vascular endothelial growth factor (VEGF) initiates angiogenesis, and VEGF or its receptor is targeted therapeutically to block pathological angiogenesis. Additional pro-angiogenic cues, such as CXCL12 acting via the CXCR4 receptor, co-operate with VEGF/VEGFR2 to cue vascular patterning. We studied the role of FGD5, an endothelial Rho GTP/GDP exchange factor (RhoGEF), to regulate CXCR4-dependent signals in the endothelial cell (EC). Patient-derived renal cell carcinomas produce a complex milieu of growth factors that stimulated sprouting angiogenesis and endothelial tip cell differentiation ex vivo that was blocked by EC FGD5 loss. In a simplified model, CXCL12 augmented sprouting and tip gene expression under conditions where VEGF was limiting. CXCL12-stimulated tip cell differentiation was dependent on PI3 kinase (PI3K)-β activity. Knockdown of EC FGD5 abolished CXCR4 signaling to PI3K-β and Akt. Further, inhibition of Rac1, a Rho GTPase required for PI3K-β activity, recapitulated the signaling defects of FGD5 deficiency, suggesting that FGD5 may regulate PI3K-β activity through Rac1. Overexpression of a RhoGEF deficient, Dbl domain-deleted FGD5 mutant reduced CXCL12-stimulated Akt phosphorylation and failed to rescue PI3K signaling in native FGD5-deficient EC, indicating that FGD5 RhoGEF activity is required for FDG5 function. Endothelial expression of mutant PI3K-β with an inactivated Rho binding domain confirmed that CXCL12-stimulated PI3K activity in EC requires Rac1-GTP co-regulation. Together, this data identify the role of FGD5 to generate Rac1-GTP to regulate pro-angiogenic CXCR4-dependent PI3K-β signaling in EC. Inhibition of FGD5 activity may complement current angiogenesis inhibitor drugs.

Importance of Thai macaque bioresources for biological research and human health

During the past century, macaque bioresources have provided remarkable scientific and biomedical discoveries related to the understanding of human physiology, neuroanatomy, reproduction, development, cognition, and pathology. Considerable progress has been made, and an urgent need has arisen to develop infrastructure and viable settings to meet the current global demand in research models during the so-called new normal after COVID-19 era. This review highlights the critical need for macaque bioresources and proposes the establishment of a designated primate research center to integrate research in primate laboratories for the rescue and rehabilitation of wild macaques. Key areas where macaque models have been and continue to be essential for advancing fundamental knowledge in biomedical and biological research are outlined. Detailed genetic studies on macaque bioresources of Thai origin can further facilitate the rapid pace of vaccine discovery.

Hypoxia conditioned mesenchymal stem cells in tissue regeneration application

Mesenchymal stem cells (MSCs) have been demonstrated as promising cell sources for tissue regeneration due to their capability of self-regeneration, differentiation and immunomodulation. MSCs also exert extensive paracrine effects through release of trophic factors and extracellular vesicles. However, despite extended exploration of MSCs in pre-clinical studies, the results are far from satisfactory due to the poor engraftment and low level of survival after implantation. Hypoxia preconditioning has been proposed as an engineering approach to improve the therapeutic potential of MSCs. During in vitro culture, hypoxic conditions can promote MSC proliferation, survival and migration through various cellular responses to the reduction of oxygen tension. The multilineage differentiation potential of MSCs is altered under hypoxia, with consistent reports of enhanced chondrogenesis. Hypoxia also stimulates the paracrine activities of MSCs and increases the production of secretome both in terms of soluble factors as well as extracellular vesicles. The secretome from hypoxia preconditioned MSCs play important roles in promoting cell proliferation and migration, enhancing angiogenesis while inhibiting apoptosis and inflammation. In this review, we summarise current knowledge of hypoxia-induced changes in MSCs and discuss the application of hypoxia preconditioned MSCs as well as hypoxic secretome in different kinds of disease models.

Lymphatic-specific intracellular modulation of receptor tyrosine kinase signaling improves lymphatic growth and function

Exogenous administration of lymphangiogenic growth factors is widely used to study changes in lymphatic function in pathophysiology. However, this approach can result in off-target effects, thereby generating conflicting data. To circumvent this issue, we modulated intracellular VEGF-C signaling by conditionally knocking out the lipid phosphatase PTEN using the Vegfr3 promoter to drive the expression of Cre-lox in lymphatic endothelial cells (LECs). PTEN is an intracellular brake that inhibits the downstream effects of the activation of VEGFR3 by VEGF-C. Activation of Cre-lox recombination in adult mice resulted in an expanded functional lymphatic network due to LEC proliferation that was independent of lymphangiogenic growth factor production. Furthermore, compared with lymphangiogenesis induced by VEGF-C injection, LECPTEN animals had mature, nonleaky lymphatics with intact cell-cell junctions and reduced local tissue inflammation. Last, compared with wild-type or VEGF-C-injected mice, LECPTEN animals had an improved capacity to resolve inflammatory responses. Our findings indicate that intracellular modulation of lymphangiogenesis is effective in inducing functional lymphatic networks and has no off-target inflammatory effects.

Effects of shear stress on differentiation of stem cells into endothelial cells

Stem cell transplantation is an appealing potential therapy for vascular diseases and an indispensable key step in vascular tissue engineering. Substantial effort has been made to differentiate stem cells toward vascular cell phenotypes, including endothelial cells (ECs) and smooth muscle cells. The microenvironment of vascular cells not only contains biochemical factors that influence differentiation but also exerts hemodynamic forces, such as shear stress and cyclic strain. More recently, studies have shown that shear stress can influence the differentiation of stem cells toward ECs. A deep understanding of the responses and underlying mechanisms involved in this process is essential for clinical translation. This review highlights current data supporting the role of shear stress in stem cell differentiation into ECs. Potential mechanisms and signaling cascades for transducing shear stress into a biological signal are proposed. Further study of stem cell responses to shear stress will be necessary to apply stem cells for pharmacological applications and cardiovascular implants in the realm of regenerative medicine.

Brain endothelial PTEN/AKT/NEDD4-2/MFSD2A axis regulates blood-brain barrier permeability

The low level of transcytosis is a unique feature of cerebrovascular endothelial cells (ECs), ensuring restrictive blood-brain barrier (BBB) permeability. Major facilitator superfamily domain-containing 2a (MFSD2A) is a key regulator of the BBB function by suppressing caveolae-mediated transcytosis. However, the mechanisms regulating MFSD2A at the BBB have been barely explored. Here, we show that cerebrovascular EC-specific deletion of Pten (phosphatase and tensin homolog) results in a dramatic increase in vesicular transcytosis by the reduction of MFSD2A, leading to increased transcellular permeability of the BBB. Mechanistically, AKT signaling inhibits E3 ubiquitin ligase NEDD4-2-mediated MFSD2A degradation. Consistently, cerebrovascular Nedd4-2 overexpression decreases MFSD2A levels, increases transcytosis, and impairs BBB permeability, recapitulating the phenotypes of Pten-deficient mice. Furthermore, Akt deletion decreases phosphorylated NEDD4-2 levels, restores MFSD2A levels, and normalizes BBB permeability in Pten-mutant mice. Altogether, our work reveals the essential physiological function of the PTEN/AKT/NEDD4-2/MFSD2A axis in the regulation of BBB permeability.

Exosomal miR-130b-3p Promotes Progression and Tubular Formation Through Targeting PTEN in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC), accounting for two-thirds of head and neck cancer, is characterized by poor prognosis and a high rate of mortality. Exosomes have emerged as potential molecule-shuttle in intercellular communication, thereby regulating the physiological processes of recipient cells. To date, the effect of exosomal microRNAs (miRNAs) on the progression of OSCC has not been fully investigated. In this study, we found that the protein, but not mRNA expression of Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) was decreased in OSCC. The results revealed that miR-130b-3p was an important negative regulator for PTEN expression. Additionally, overexpression and knockdown of miR-130b-3p enhanced and inhibited angiogenesis in human umbilical vein endothelial cells (HUVECs), respectively. Also, miR-130b-3p was transferred by exosomes to HUVECs and then promoted angiogenesis and inhibit the expression of PTEN. Furthermore, exosomal miR-130b-3p derived from OSCC cells promoted tumor growth and blood vessel formation in the xenograft mice model. Taken together, we demonstrated that exosome-mediated miR-130b-3p promoted progression and tubular formation in OSCC in vitro and in vivo. These results would provide new insight into exploring biomarkers and effective therapeutic strategies for OSCC.

Tumor Hypoxia Regulates Immune Escape/Invasion: Influence on Angiogenesis and Potential Impact of Hypoxic Biomarkers on Cancer Therapies

The environmental and metabolic pressures in the tumor microenvironment (TME) play a key role in molding tumor development by impacting the stromal and immune cell fractions, TME composition and activation. Hypoxia triggers a cascade of events that promote tumor growth, enhance resistance to the anti-tumor immune response and instigate tumor angiogenesis. During growth, the developing angiogenesis is pathological and gives rise to a haphazardly shaped and leaky tumor vasculature with abnormal properties. Accordingly, aberrantly vascularized TME induces immunosuppression and maintains a continuous hypoxic state. Normalizing the tumor vasculature to restore its vascular integrity, should hence enhance tumor perfusion, relieving hypoxia, and reshaping anti-tumor immunity. Emerging vascular normalization strategies have a great potential in achieving a stable normalization, resulting in mature and functional blood vessels that alleviate tumor hypoxia. Biomarkers enabling the detection and monitoring of tumor hypoxia could be highly advantageous in aiding the translation of novel normalization strategies to clinical application, alone, or in combination with other treatment modalities, such as immunotherapy.

Endothelial Cells as Tools to Model Tissue Microenvironment in Hypoxia-Dependent Pathologies

Endothelial cells (ECs) lining the blood vessels are important players in many biological phenomena but are crucial in hypoxia-dependent diseases where their deregulation contributes to pathology. On the other hand, processes mediated by ECs, such as angiogenesis, vessel permeability, interactions with cells and factors circulating in the blood, maintain homeostasis of the organism. Understanding the diversity and heterogeneity of ECs in different tissues and during various biological processes is crucial in biomedical research to properly develop our knowledge on many diseases, including cancer. Here, we review the most important aspects related to ECs’ heterogeneity and list the available in vitro tools to study different angiogenesis-related pathologies. We focus on the relationship between functions of ECs and their organo-specificity but also point to how the microenvironment, mainly hypoxia, shapes their activity. We believe that taking into account the specific features of ECs that are relevant to the object of the study (organ or disease state), especially in a simplified in vitro setting, is important to truly depict the biology of endothelium and its consequences. This is possible in many instances with the use of proper in vitro tools as alternative methods to animal testing.

Intrauterine Inflammation Alters the Transcriptome and Metabolome in Placenta

Placental insufficiency is implicated in spontaneous preterm birth (SPTB) associated with intrauterine inflammation. We hypothesized that intrauterine inflammation leads to deficits in the capacity of the placenta to maintain bioenergetic and metabolic stability during pregnancy ultimately resulting in SPTB. Using a mouse model of intrauterine inflammation that leads to preterm delivery, we performed RNA-seq and metabolomics studies to assess how intrauterine inflammation alters gene expression and/or modulates metabolite production and abundance in the placenta. 1871 differentially expressed genes were identified in LPS-exposed placenta. Among them, 1,149 and 722 transcripts were increased and decreased, respectively. Ingenuity pathway analysis showed alterations in genes and canonical pathways critical for regulating oxidative stress, mitochondrial function, metabolisms of glucose and lipids, and vascular reactivity in LPS-exposed placenta. Many upstream regulators and master regulators important for nutrient-sensing and mitochondrial function were also altered in inflammation exposed placentae, including STAT1, HIF1α, mTOR, AMPK, and PPARα. Comprehensive quantification of metabolites demonstrated significant alterations in the glucose utilization, metabolisms of branched-chain amino acids, lipids, purine and pyrimidine, as well as carbon flow in TCA cycle in LPS-exposed placenta compared to control placenta. The transcriptome and metabolome were also integrated to assess the interactions of altered genes and metabolites. Collectively, significant and biologically relevant alterations in the placenta transcriptome and metabolome were identified in placentae exposed to intrauterine inflammation. Altered mitochondrial function and energy metabolism may underline the mechanisms of inflammation-induced placental dysfunction.

MiR-624-3p Promotes Esophageal Squamous Cell Carcinoma Progression via Targeting Phosphatase and Tensin Homologue

The emerging role of miRNA as regulators in esophageal squamous cell carcinoma (ESCC) progression has aroused great attention recently. In this study, the effects of miR-624-3p in ESCC progression were explored through cell proliferation, colony formation, cell cycle, and apoptosis analyses. Results showed that increased expression of miR-624-3p enhanced cancer cell viability, proliferation, migration, and invasion but inhibited apoptosis in ESCC. Moreover, luciferase reporter assay demonstrated that miR-624-3p bound to the 3'-untranslated region of phosphatase and tensin homologue (PTEN). Further study showed that miR-624-3p exerted its tumor promoting role through targeting PTEN. Taken together, these results elucidate the regulatory role of miR-624-3p in ESCC progression, shedding light on its possible clinical application in ESCC treatment.

Inactivation of endothelial cell phosphoinositide 3-kinase β inhibits tumor angiogenesis and tumor growth

Angiogenesis inhibitors, such as the receptor tyrosine kinase (RTK) inhibitor sunitinib, target vascular endothelial growth factor (VEGF) signaling in cancers. However, only a fraction of patients respond, and most ultimately develop resistance to current angiogenesis inhibitor therapies. Activity of alternative pro-angiogenic growth factors, acting via RTK or G-protein coupled receptors (GPCR), may mediate VEGF inhibitor resistance. The phosphoinositide 3-kinase (PI3K)β isoform is uniquely coupled to both RTK and GPCRs. We investigated the role of endothelial cell (EC) PI3Kβ in tumor angiogenesis. Pro-angiogenic GPCR ligands were expressed by patient-derived renal cell carcinomas (PD-RCC), and selective inactivation of PI3Kβ reduced PD-RCC-stimulated EC spheroid sprouting. EC-specific PI3Kβ knockout (ΕC-βKO) in mice potentiated the sunitinib-induced reduction in subcutaneous growth of LLC1 and B16F10, and lung metastasis of B16F10 tumors. Compared to single-agent sunitinib treatment, tumors in sunitinib-treated ΕC-βKO mice showed a marked decrease in microvessel density, and reduced new vessel formation. The fraction of perfused mature tumor microvessels was increased in ΕC-βKO mice suggesting immature microvessels were most sensitive to combined sunitinib and PI3Kβ inactivation. Taken together, EC PI3Kβ inactivation with sunitinib inhibition reduces microvessel turnover and decreases heterogeneity of the tumor microenvironment, hence PI3Kβ inhibition may be a useful adjuvant antiangiogenesis therapy with sunitinib.

Immune phenotyping of diverse syngeneic murine brain tumors identifies immunologically distinct types

Immunotherapy has emerged as a promising approach to treat cancer, however, its efficacy in highly malignant brain-tumors, glioblastomas (GBM), is limited. Here, we generate distinct imageable syngeneic mouse GBM-tumor models and utilize RNA-sequencing, CyTOF and correlative immunohistochemistry to assess immune-profiles in these models. We identify immunologically-inert and -active syngeneic-tumor types and show that inert tumors have an immune-suppressive phenotype with numerous exhausted CD8 T cells and resident macrophages; fewer eosinophils and SiglecF+ macrophages. To mimic the clinical-settings of first line of GBM-treatment, we show that tumor-resection invigorates an anti-tumor response via increasing T cells, activated microglia and SiglecF+ macrophages and decreasing resident macrophages. A comparative CyTOF analysis of resected-tumor samples from GBM-patients and mouse GBM-tumors show stark similarities in one of the mouse GBM-tumors tested. These findings guide informed choices for use of GBM models for immunotherapeutic interventions and offer a potential to facilitate immune-therapies in GBM patients.

Syngeneic mouse models for glioblastoma (GBM) cannot fully recapitulate clinical findings and response to therapy in patients. Here the authors perform a comprehensive immune profiling of different syngeneic GBM tumour models and compare it with the immune landscape of GBM patients to identify similarities and potential confounding differences.

Extracranial arteriovenous malformations: from bedside to bench

Arteriovenous malformation (AVM) is defined as a fast-flow vascular anomaly that shunts blood from arteries directly to veins. This short circuit of blood flow contributes to progressive expansion of draining veins, resulting in ischaemia, tissue deformation and in some severe cases, congestive heart failure. Various medical interventions have been employed to treat AVM, however, management of which remains a huge challenge because of its high recurrence rate and lethal complications. Thus, understanding the underlying mechanisms of AVM development and progression will help direct discovery and a potential cure. Here, we summarize current findings in the field of extracranial AVMs with the aim to provide insight into their aetiology and molecular influences, in the hope to pave the way for future treatment.

Shear Stress Triggers Angiogenesis of Late Endothelial Progenitor Cells via the PTEN/Akt/GTPCH/BH4 Pathway

Background

Shear stress is an effective modulator of endothelial progenitor cells (EPCs) and has been suggested to play an important role in angiogenesis. The phosphatase and tensin homolog (PTEN)/Akt and guanosine triphosphate cyclohydrolase (GTPCH)/tetrahydrobiopterin (BH4) pathways regulate the function of early EPCs. However, the role of these pathways in the shear stress-induced angiogenesis of late EPCs remains poorly understood. Therefore, we aim to investigate whether shear stress could upregulate the angiogenesis capacity of late EPCs and to further explore the possible underlying mechanisms.

Methods

Late EPCs were subjected to laminar shear stress (LSS), and their in vitro migration, proliferation, and tube formation capacity were determined. In addition, the in vivo angiogenesis capacity was explored, along with the expression of molecules involved in the PTEN/Akt and GTPCH/BH4 pathways.

Results

LSS elevated the in vitro activities of late EPCs, which were accompanied by downregulated PTEN expression, accelerated Akt phosphorylation, and GTPCH/BH4 pathway activation (all P < 0.05). Following Akt inhibition, LSS-induced upregulated GTPCH expression, BH4, and NO level of EPCs were suppressed. LSS significantly improved the migration, proliferation, and tube formation ability (15 dyn/cm² LSS vs. stationary: 72.2 ± 5.5 vs. 47.3 ± 7.3, 0.517 ± 0.05 vs. 0.367 ± 0.038, and 1.664 ± 0.315 vs. 1 ± 0, respectively; all P < 0.05) along with the in vivo angiogenesis capacity of late EPCs, contributing to the recovery of limb ischemia. These effects were also blocked by Akt inhibition or GTPCH knockdown (P < 0.05, respectively).

Conclusions

This study provides the first evidence that shear stress triggers angiogenesis in late EPCs via the PTEN/Akt/GTPCH/BH4 pathway, providing a potential nonpharmacologic therapeutic strategy for promoting angiogenesis in ischemia-related diseases.

Naringin inhibits colorectal cancer cell growth by repressing the PI3K/AKT/mTOR signaling pathway

In recent years, the incidence of colorectal cancer (CRC) has increased and research into new treatment methods for CRC has become a hot topic. Naringin has an inhibitory effect on the PI3k/AKT/mTOR signaling pathway in various tumor cell types and the effect of naringin is closely related to the occurrence and proliferation of tumor cells. The aim of this present study was to investigate whether naringin could inhibit the proliferation of CRC cells by inhibiting the PI3K/AKT/mTOR signaling pathway. This could provide a more mechanism-based treatment for CRC. MTT assays were used to detect the proliferation of CRC cells treated with various concentrations of naringin. The degree of apoptosis and the expression of apoptosis-related proteins (Bcl-2 and Bax) in CRC cells stimulated by naringin was detected using flow cytometry and western blot assays, respectively. The expression levels of PI3K/AKT/mTOR-related proteins [PI3K, AKT, mTOR, phosphorylated (p)-PI3K, p-AKT and p-mTOR] after naringin stimulation in CRC cells were detected using western blot assays. Naringin inhibited the proliferation of CRC cells in a dose-dependent manner. Naringin promoted the apoptosis of CRC cells and inhibited the activation of the PI3K/AKT/mTOR signaling pathway in a dose-dependent manner. The results demonstrated that naringin may be a promising therapeutic agent for the treatment of CRC, which may inhibit the proliferation of CRC cells and induce apoptosis by inhibiting the PI3K/AKT/mTOR signaling pathway.

Characterization of Antineovascularization Activity and Ocular Pharmacokinetics of Phosphoinositide 3-Kinase/Mammalian Target of Rapamycin Inhibitor GNE-947

The objectives of the present study were to characterize GNE-947 for its phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) inhibitory activities, in vitro anti-cell migration activity in human umbilical vein endothelial cells (HUVECs), in vivo antineovascularization activity in laser-induced rat choroidal neovascular (CNV) eyes, pharmacokinetics in rabbit plasma and eyes, and ocular distribution using matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) and autoradioluminography. Its PI3K and mTOR K _i were 0.0005 and 0.045 µM, respectively, and its HUVEC IC₅₀ was 0.093 µM. GNE-947 prevented neovascularization in the rat CNV model at 50 or 100 µg per eye with repeat dosing. After a single intravenous injection at 2.5 and 500 μg/kg in rabbits, its plasma terminal half-lives (t _1/2) were 9.11 and 9.59 hours, respectively. After a single intravitreal injection of a solution at 2.5 μg per eye in rabbits, its apparent t _1/2 values were 14.4, 16.3, and 23.2 hours in the plasma, vitreous humor, and aqueous humor, respectively. After a single intravitreal injection of a suspension at 33.5, 100, 200 μg per eye in rabbits, the t _1/2 were 29, 74, and 219 days in the plasma and 46, 143, and 191 days in the eyes, respectively. MALDI-IMS and autoradioluminography images show that GNE-947 did not homogenously distribute in the vitreous humor and aggregated at the injection sites after injection of the suspension, which was responsible for the long t _1/2 of the suspension because of the slow dissolution process. This hypothesis was supported by pharmacokinetic modeling analyses. In conclusion, the PI3K/mTOR inhibitor GNE-947 prevented neovascularization in a rat CNV model, with t _1/2 up to approximately 6 months after a single intravitreal injection of the suspension in rabbit eyes. SIGNIFICANCE STATEMENT: GNE-947 is a potent phosphoinositide 3-kinase/mammalian target of rapamycin inhibitor and exhibits anti-choroidal neovascular activity in rat eyes. The duration of GNE-947 in the rabbit eyes after intravitreal injection in a solution is short, with a half-life (t _1/2) of less than a day. However, the duration after intravitreal dose of a suspension is long, with t _1/2 up to 6 months due to low solubility and slow dissolution. These results indicate that intravitreal injection of a suspension for low-solubility drugs can be used to achieve long-term drug exposure.

miR-136-3p targets PTEN to regulate vascularization and bone formation and ameliorates alcohol-induced osteopenia

Alcohol consumption is regarded as one of the leading risk factors for secondary osteopenia. Coupled angiogenesis and osteogenesis via distinct type-H vessels orchestrates subtle biological processes of bone homeostasis. The dysfunction of angiogenesis and osteogenesis contributes to decreased bone mass during the development of osteopenia. Herein, we identified microRNA-136-3p was remarkedly downregulated in the mouse model of alcohol-induced osteopenia. Following the alcohol administration, downregulated microRNA-136-3p significantly suppressed vascularization and osteogenic differentiation in human umbilical vein endothelial cells (HUVECs) and bone mesenchymal stem cells (BMSCs), respectively. Furthermore, microRNA-136-3p could target phosphatase and tensin homolog deleted on chromosome ten (PTEN) in both HUVECs and BMSCs, thus substantially modulating the capacity of vessel formation and osteogenic differentiation. In the mouse model, microRNA-136-3p Agomir ameliorated alcohol-induced osteopenia, with the concomitant restoration of bone mass and type-H vessel formation. For the first time, this study demonstrated the pivotal role of microRNA-136-3p/PTEN axis in regulations of vascularization and bone formation, which might become the potential therapeutic target of alcohol-induced bone loss.

First-in-Human Phase I Study to Evaluate the Brain-Penetrant PI3K/mTOR Inhibitor GDC-0084 in Patients with Progressive or Recurrent High-Grade Glioma

PURPOSE

GDC-0084 is an oral, brain-penetrant small-molecule inhibitor of PI3K and mTOR. A first-in-human, phase I study was conducted in patients with recurrent high-grade glioma.

PATIENTS AND METHODS

GDC-0084 was administered orally, once daily, to evaluate safety, pharmacokinetics (PK), and activity. Fluorodeoxyglucose-PET (FDG-PET) was performed to measure metabolic responses.

RESULTS

Forty-seven heavily pretreated patients enrolled in eight cohorts (2-65 mg). Dose-limiting toxicities included 1 case of grade 2 bradycardia and grade 3 myocardial ischemia (15 mg), grade 3 stomatitis (45 mg), and 2 cases of grade 3 mucosal inflammation (65 mg); the MTD was 45 mg/day. GDC-0084 demonstrated linear and dose-proportional PK, with a half-life (∼19 hours) supportive of once-daily dosing. At 45 mg/day, steady-state concentrations exceeded preclinical target concentrations producing antitumor activity in xenograft models. FDG-PET in 7 of 27 patients (26%) showed metabolic partial response. At doses ≥45 mg/day, a trend toward decreased median standardized uptake value in normal brain was observed, suggesting central nervous system penetration of drug. In two resection specimens, GDC-0084 was detected at similar levels in tumor and brain tissue, with a brain tissue/tumor-to-plasma ratio of >1 and >0.5 for total and free drug, respectively. Best overall response was stable disease in 19 patients (40%) and progressive disease in 26 patients (55%); 2 patients (4%) were nonevaluable.

CONCLUSIONS

GDC-0084 demonstrated classic PI3K/mTOR-inhibitor related toxicities. FDG-PET and concentration data from brain tumor tissue suggest that GDC-0084 crossed the blood-brain barrier.

Imaging of PTEN-related abnormalities in the central nervous system

The phosphatase and tensin homolog (PTEN) located at 10q23.31 is a tumor suppressor gene expressed ubiquitously, and loss of function mutations lead to aberrant growth, angiogenesis, and an increased risk for a variety of tumors. PTEN mutations have been associated with multiple abnormalities in the central nervous system, and a number of clinical phenotypes are now attributed to germline PTEN mutations, collectively referred to as PTEN hamartoma tumor syndrome (PHTS). Most notably, these include Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), and autism spectrum disorders with macrocephaly. It is important to recognize the neuroimaging features associated with PTEN mutations to not only avoid misdiagnosis in cases of known PHTS but also to guide genetic testing in patients who do not yet have an established diagnosis. In this review, the central nervous system imaging features of PTEN-related disorders are discussed.

Revisiting PI3-kinase signalling in angiogenesis

PI3Ks belong to a family of lipid kinases that comprises eight isoforms. They phosphorylate the third position of the inositol ring present in phosphatidylinositol lipids and, in turn, activate a broad range of proteins. The PI3K pathway regulates primal cellular responses, including proliferation, migration, metabolism and vesicular traffic. These processes are fundamental for endothelial cell function during sprouting angiogenesis, the most common type of blood vessel formation. Research in animal models has revealed key functions of PI3K family members and downstream effectors in angiogenesis. In addition, perturbations in PI3K signalling have been associated with aberrant vascular growth including tumour angiogenesis and vascular malformations. Together, this highlights that endothelial cells are uniquely sensitive to fluctuations in PI3K signalling. Here, we aim to update the current view on this important signalling cue in physiological and pathological blood vessel growth.

PTEN in the Stroma

Although tremendous progress has been made in understanding the functions of Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in tumor cells, only recently have tumor cell-non-autonomous PTEN actions within the tumor microenvironment (TME) been appreciated. While it is accepted that the TME actively communicates with cancer cells to influence disease progression, our understanding of the genes and pathways responsible is still evolving. Given that inactivation of PTEN in the stroma is correlated with worse outcomes in human cancers, determining the unique functions and mechanisms of PTEN regulation in various TME cell compartments is essential. In this review, the evidence for PTEN function in different TME cell compartments, the mechanisms governing PTEN inactivation, and the downstream pathways regulated by PTEN that are critical for intracellular communication, are covered. The potential clinical implications of these findings as well as the future directions for the study of stromal PTEN are discussed.

Predicting Functional Responses of Progenitor Cell Exosome Potential with Computational Modeling

Congenital heart disease can lead to severe right ventricular heart failure (RVHF). We have shown that aggregated c‐kit⁺ progenitor cells (CPCs) can improve RVHF repair, likely due to exosome‐mediated effects. Here, we demonstrate that miRNA content from monolayer (2D) and aggregated (3D) CPC exosomes can be related to in vitro angiogenesis and antifibrosis responses using partial least squares regression (PLSR). PLSR reduced the dimensionality of the data set to the top 40 miRNAs with the highest weighted coefficients for the in vitro biological responses. Target pathway analysis of these top 40 miRNAs demonstrated significant fit to cardiac angiogenesis and fibrosis pathways. Although the model was trained on in vitro data, we demonstrate that the model can predict angiogenesis and fibrosis responses to exosome treatment in vivo with a strong correlation with published in vivo responses. These studies demonstrate that PLSR modeling of exosome miRNA content has the potential to inform preclinical trials and predict new promising CPC therapies. stem cells translational medicine2019;8:1212–1221

Rational Design of Novel Phosphoinositide 3-Kinase Gamma (PI3Kγ) Selective Inhibitors: A Computational Investigation Integrating 3D-QSAR, Molecular Docking and Molecular Dynamics Simulation

Phosphoinositide 3-kinase gamma (PI3Kγ) draws an increasing attention due to its link with deadly cancer, chronic inflammation and allergy. But the development of PI3Kγ selective inhibitors is still a challenging endeavor because of the high sequence homology with the other PI3K isoforms. In order to acquire valuable information about the interaction mechanism between potent inhibitors and PI3Kγ, a series of PI3Kγ isoform-selective inhibitors were analyzed by a systematic computational method, combining 3D-QSAR, molecular docking, molecular dynamic (MD) simulations, free energy calculations and decomposition. The general structure-activity relationships were revealed and some key residues relating to selectivity and high activity were highlighted. It provides precious guidance for rational virtual screening, modification and design of selective PI3Kγ inhibitors. Finally, ten novel inhibitors were optimized and P10 showed satisfactory predicted bioactivity, demonstrating the feasibility to develop potent PI3Kγ inhibitors through this computational modeling and optimization.

Endothelial to Mesenchymal Transition in Cardiovascular Disease: JACC State-of-the-Art Review

Endothelial to mesenchymal transition (EndMT) is a process whereby an endothelial cell undergoes a series of molecular events that lead to a change in phenotype toward a mesenchymal cell (e.g., myofibroblast, smooth muscle cell). EndMT plays a fundamental role during development, and mounting evidence indicates that EndMT is involved in adult cardiovascular diseases (CVDs), including atherosclerosis, pulmonary hypertension, valvular disease, and fibroelastosis. Therefore, the targeting of EndMT may hold therapeutic promise for treating CVD. However, the field faces a number of challenges, including the lack of a precise functional and molecular definition, a lack of understanding of the causative pathological role of EndMT in CVDs (versus being a "bystander-phenomenon"), and a lack of robust human data corroborating the extent and causality of EndMT in adult CVDs. Here, we review this emerging but exciting field, and propose a framework for its systematic advancement at the molecular and translational levels.

Arthroscopic Excision of Angio-Fibro-Lipomatous Hamartoma of the Knee: A Rare Case Report

Angio-fibro-lipomatous hamartoma is a benign adipose tissue tumor very rarely seen in musculoskeletal distribution, and its incidence in the knee joint has never been reported. The patient in our case presented with knee pain of 2 years' duration, following blunt trauma. Preoperatively, veno-lymphatic malformation/hemangioma was considered as the diagnosis. Only after arthroscopic excision biopsy, histopathological examination, retrospective radiological analysis, and a review of literature, we were able to diagnose this rare condition. The histopathological picture of this benign adipose tissue tumor contained a mixture of mature adipose tissue and fibrous and vascular tissues. Here, in this case report, we discuss about PTEN gene causing PTEN hamartoma of soft tissue and angiolipoma presentations and its variants.

To Explore the Pathogenesis of Vascular Lesion of Type 2 Diabetes Mellitus Based on the PI3K/Akt Signaling Pathway

BACKGROUND

Type 2 diabetes mellitus (T2DM) has become a chronic disease, serious harm to human health. Complications of the blood pipe are the main cause of disability and death in diabetic patients, including vascular lesions that directly affects the prognosis of patients with diabetes and survival. This study was to determine the influence of high glucose and related mechanism of vascular lesion of type 2 diabetes mellitus pathogenesis.

METHODS

In vivo aorta abdominalis of GK rats was observed with blood pressure, heart rate, hematoxylin and eosin (H&E), Masson, and Verhoeff staining. In vitro cells were cultured with 30 mM glucose for 24 h. RT-QPCR was used to detect the mRNA expression of endothelial markers PTEN, PI3K, Akt, and VEGF. Immunofluorescence staining was used to detect the expression of PTEN, PI3K, Akt, and VEGF. PI3K and Akt phosphorylation levels were detected by Western blot analysis.

RESULTS

Heart rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure in the GK control group were higher compared with the Wistar control group and no difference compared with the GK experimental model group. Fluorescence intensity of VEGF, Akt, and PI3K in the high-sugar stimulus group was stronger than the control group; PTEN in the high-sugar stimulus group was weakening than the control group. VEGF, Akt, and PI3K mRNA in the high-sugar stimulus group were higher than the control group; protein expressions of VEGF, Akt, and PI3K in the high-sugar stimulus group were higher than the control group. PTEN mRNA in the high-sugar stimulus group was lower than the control group. Protein expression of PTEN in the high-sugar stimulus group was lower than the control group.

CONCLUSIONS

Angiogenesis is an important pathogenesis of T2DM vascular disease, and PTEN plays a negative regulatory role in the development of new blood vessels and can inhibit the PI3K/Akt signaling pathway.

Effective angiogenesis requires regulation of phosphoinositide signaling

Phosphoinositide signaling regulates numerous downstream effectors that mediate cellular processes which influence cell cycle progression, migration, proliferation, growth, survival, metabolism and vesicular trafficking. A prominent role for phosphoinositide 3-kinase, which generates phosphatidylinositol 3,4,5-trisphosphate, a phospholipid that activates a plethora of effectors including AKT and FOXO during embryonic and postnatal angiogenesis, has been described. In addition, phosphatidylinositol 3-phosphate signaling is required for endosomal trafficking, which contributes to vascular remodeling. This review will examine the role phosphoinositide signaling plays in the endothelium and its contribution to sprouting angiogenesis.

Restoration of tumour-growth suppression in vivo via systemic nanoparticle-mediated delivery of PTEN mRNA

PTEN is a well-characterized tumour-suppressor gene that is lost or mutated in about half of metastatic castration-resistant prostate cancers and in many other human cancers. The restoration of functional PTEN as a treatment for prostate cancer has however proven difficult. Here, we show that PTEN mRNA can be reintroduced into PTEN-null prostate cancer cells in vitro and in vivo via its encapsulation in polymer-lipid hybrid nanoparticles coated with a poly(ethylene glycol) shell. The nanoparticles are stable in serum, elicit low toxicity, enable high PTEN mRNA transfection in prostate cancer cells, and lead to significant inhibition of tumour growth when delivered systemically in multiple mouse models of prostate cancer. We also show that the restoration of PTEN function in PTEN-null prostate cancer cells inhibits the PI3K-AKT pathway and enhances apoptosis. Our findings provide proof-of-principle evidence of the restoration of mRNA-based tumour suppression in vivo.

Circulating miRNome profiling in Moyamoya disease-discordant monozygotic twins and endothelial microRNA expression analysis using iPS cell line

Background

Moyamoya disease (MMD) is characterized by progressive stenosis of intracranial arteries in the circle of Willis with unknown etiology even after the identification of a Moyamoya susceptible gene, RNF213. Recently, differences in epigenetic regulations have been investigated by a case-control study in MMD. Here, we employed a disease discordant monozygotic twin-based study design to unmask potential confounders.

Methods

Circulating genome-wide microRNA (miRNome) profiling was performed in MMD-discordant monozygotic twins, non-twin-MMD patients, and non-MMD healthy volunteers by microarray followed by qPCRvalidation, using blood samples. Differential plasma-microRNAs were further quantified in endothelial cells differentiated from iPS cell lines (iPSECs) derived from another independent non-twin cohort. Lastly, their target gene expression in the iPSECs was analyzed.

Results

Microarray detected 309 plasma-microRNAs in MMD-discordant monozygotic twins that were also detected in the non-twin cohort. Principal component analysis of the plasma-microRNA expression level demonstrated distinct 2 groups separated by MMD and healthy control in the twin- and non-twin cohorts. Of these, differential upregulations of hsa-miR-6722-3p/− 328-3p were validated in the plasma of MMD (absolute log2 expression fold change (logFC) > 0.26 for the twin cohort; absolute logFC > 0.26, p < 0.05, and q < 0.15 for the non-twin cohort). In MMD derived iPSECs, hsa-miR-6722-3p/− 328-3p showed a trend of up-regulation with a 3.0- or higher expression fold change. Bioinformatics analysis revealed that 41 target genes of miR-6722-3p/− 328-3p were significantly down-regulated in MMD derived iPSECs and were involved in STAT3, IGF-1-, and PTEN-signaling, suggesting a potential microRNA-gene expression interaction between circulating plasma and endothelial cells.

Conclusions

Our MMD-discordant monozygotic twin-based study confirmed a novel circulating microRNA signature in MMD as a potential diagnostic biomarker minimally confounded by genetic heterogeneity. The novel circulating microRNA signature can contribute for the future functional microRNA analysis to find new diagnostic and therapeutic target of MMD.

Electronic supplementary material

The online version of this article (10.1186/s12920-018-0385-3) contains supplementary material, which is available to authorized users.