Expression Of Angiopoietin-1 Research Articles

Angiopoietin-1 Upregulates Cancer Cell Motility in Colorectal Cancer Liver Metastases through Actin-Related Protein 2/3.

Simple SummaryVessel co-option has been recognized as a mechanism associated with resistance to anti-angiogenic treatment in colorectal cancer liver metastases (CRCLMs). Recently, we reported that Angiopoietin-1 (Ang1) stimulates vessel co-option in CRCLM through an unknown mechanism. In this manuscript, we found the molecular pathways that mediate the function of Ang1 in CRCLM. We showed that Ang1 induces the expression levels of actin-related protein 2/3 (ARP2/3) in the cancer cells via various mechanisms. Importantly, different studies have shown that high levels of ARP2/3 in cancer cells are essential for the formation of vessel co-opting CRCLM tumours. Highlighting these pathways is an important step to identify therapeutic strategies to overcome vessel co-option and resistance to anti-angiogenic therapy in CRCLM.Resistance to anti-angiogenic therapy is a major challenge in the treatment of colorectal cancer liver metastases (CRCLMs). Vessel co-option has been identified as a key contributor to anti-angiogenic therapy resistance in CRCLMs. Recently, we identified a positive correlation between the expression of Angiopoietin1 (Ang1) in the liver and the development of vessel co-opting CRCLM lesions in vivo. However, the mechanisms underlying its stimulation of vessel co-option are unclear. Herein, we demonstrated Ang1 as a positive regulator of actin-related protein 2/3 (ARP2/3) expression in cancer cells, in vitro and in vivo, which is known to be essential for the formation of vessel co-option in CRCLM. Significantly, Ang1-dependent ARP2/3 expression was impaired in the cancer cells upon Tie2 or PI3K/AKT inhibition in vitro. Taken together, our results suggest novel mechanisms by which Ang1 confers the development of vessel co-option in CRCLM, which, targeting this pathway, may serve as promising therapeutic targets to overcome the development of vessel co-option in CRCLM.

The natural compound atraric acid suppresses androgen-regulated neo-angiogenesis of castration-resistant prostate cancer through angiopoietin 2

Castration-resistant prostate cancer (CRPC) is an aggressive lethal form of prostate cancer (PCa). Atraric acid (AA) not only inhibits the wild-type androgen receptor (AR) but also those AR mutants that confer therapy resistance to other clinically used AR antagonists, indicating a different mode of AR antagonism. AA induces cellular senescence and inhibits CRPC tumour growth in in vivo xenograft mouse model associated with reduced neo-angiogenesis suggesting the repression of intratumoural neo-angiogenesis by AA. In line with this, the secretome of CRPC cells mediates neo-angiogenesis in an androgen-dependent manner, which is counteracted by AA. This was confirmed by two in vitro models using primary human endothelial cells. Transcriptome sequencing revealed upregulated angiogenic pathways by androgen, being however VEGF-independent, and pointing to the pro-angiogenic factor angiopoietin 2 (ANGPT2) as a key driver of neo-angiogenesis induced by androgens and repressed by AA. In agreement with this, AA treatment of native patient-derived PCa tumour samples ex vivo inhibits ANGPT2 expression. Mechanistically, in addition to AA, immune-depletion of ANGPT2 from secretome or blocking ANGPT2-receptors inhibits androgen-induced angiogenesis. Taken together, we reveal a VEGF-independent ANGPT2-mediated angiogenic pathway that is inhibited by AA leading to repression of androgen-regulated neo-angiogenesis.

MO270: N-3-Oxododecanoyl Homoserine Lactone Inhibits Angiogenesis by Activating the Angiopoietin-Tie System in Human Endothelial Cells

Abstract BACKGROUND AND AIMS The dysregulation of the angiopoietin–Tie system is associated with the development of sepsis-associated endothelial dysfunction. Bacterial quorum-sensing molecules act as pathogen-associated molecular patterns; however, the effect of quorum-sensing molecules on the angiopoietin–Tie system remains uncertain. METHOD This study investigated the molecular mechanisms of endothelial dysfunction in human umbilical vein endothelial cells treated with N-3-oxododecanoyl homoserine lactone (3OC12-HSL) derived from Pseudomonas aeruginosa. RESULTS Treatment with 3OC12-HSL reduced cell viability in a dose-dependent manner. Moreover, 3OC12-HSL treatment impaired the ability of tube formation even at non-lethal concentrations. The patterns of mRNA expression regarding the angiopoietin-Tie axis were assessed and the increased mRNA expressions of angiopoietin-2, Foxo-1, Tie1, and VEGFR2 were found in the 3OC12-HSL-treated cells. Western blot revealed that treatment with 3OC12-HSL increased the relative expressions of agiopoietin-2 and Foxo-1 and decreased the expression of Tie2. The study further evaluated the expression of IQGAP1 and the expressions of IQGAP1 and Rac1 decreased in cells treated with 3OC12-HSL. In addition, coimmunoprecipitation studies showed that treatment with 3OC12-HSL decreased the association between IQGAP1 and Rac1 in endothelial cells. CONCLUSION 3OC12-HSL can impair endothelial angiogenesis via the activation of the angiopoietin-Tie pathway. In addition, it may induce the dissociation of IQGAP1 with Rac1. Adjuvant therapy for blocking the quorum-sensing systems can help preserve endothelial cell integrity and prevent organ failure in patients with sepsis.

Mechanical Tension‐induced Vascular and Alveolar Morphogenesis during Lung Regeneration

Mechanical forces altered after unilateral pneumonectomy (PNX) control post‐PNX vascular and alveolar morphogenesis. This study aims to understand the mechanosensitive mechanism of lung vascular and alveolar regeneration in the post‐PNX mouse lungs. Vascular formation is stimulated at the subpleural region in the remaining mouse lung after unilateral PNX, where mechanical stretch is enhanced, while inhibition of mechanical tension by insertion of prosthesis attenuates these effects. The focal adhesion protein, paxillin senses mechanical stretch after PNX and the levels of paxillin are upregulated in SPB‐positive alveolar epithelial type II (ATII) cells and endothelial cells (ECs), which stimulates the expression of angiogenic factor angiopoietin‐1 (Ang1) in ATII cells and Ang2 in ECs to induce EC directional motility to the subpleural region. Cellular stretching increases the expression of paxillin, which induces expression of Ang2 in ECs and Ang1 in ATII cells in vitro. Post‐PNX lung growth and vascular formation toward the subpleural region are suppressed in Pxnfl/fl‐Sftpc‐CreERT2 mouse lungs, in which paxillin expression is attenuated in ATII cells. Structure of lamellar bodies that control surfactant homeostasis is also disrupted in post‐PNX Pxnfl/fl‐Sftpc‐CreERT2 mouse lung ATII cells. These results suggest that cooperative action of mechanosensitive paxillin signaling in ECs and ATII cells mediates vascular and alveolar epithelial formation during post‐PNX lung growth.

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

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

Angiopoietin2-mediated caveolin1 phosphorylation regulating transcytosis of renal tubular epithelial cell contributes to the occurrence of albuminuria under high glucose exposure

BackgroundMicrolbuminuria is the earliest clinical evidence of diabetic kidney disease (DKD) and contributes to the induction and/or progression of DKD. Previous studies have shown that increased expression of angiopoietin2 (ANGPT2) is correlated with an increase in albuminuria. However, the critical role of ANGPT2 in albuminuria development remains unclear. Some studies have shown the significance of transcytosis in the occurrence of albuminuria, but it is unknown whether it takes place in albumin recycling in renal tubular cells of patients with DKD. Furthermore, the potential mechanism of this association also remains unclear.MethodsIn this study, human renal tubular epithelial cells (HK-2) were cultured with high glucose in a Transwell plate to establish a transcytosis model, while C57BL/6 mice were intraperitoneally injected with streptozotocin to establish a DKD model. The expression of ANGPT2 and caveolin1 (CAV1) phosphorylation was dectected through immunohistochemistry and western blot analysis.ResultsTranscytosis of albumin in renal tubular epithelial cells was downregulated after high glucose exposure, and increased expression of ANGPT2 and CAV1 phosphorylation both in vivo and in vitro was observed. Inhibition of ANGPT2 and CAV1 independently promoted transcytosis. Furthermore, ANGPT2 downregulation inhibited CAV1 phosphorylation, whereas CAV1 phosphorylation had no effect on the expression of ANGPT2.ConclusionsANGPT2 reduces albumin transcytosis across renal tubular epithelial cells under high glucose conditions by activating CAV1 phosphorylation, thus increasing albuminuria in DKD. These findings suggested that ANGPT2 and CAV1 may be promising therapeutic targets for albuminuria in DKD.

Microvascular remodeling and altered angiogenic signaling in human kidneys distal to occlusive atherosclerotic renal artery stenosis.

Renal artery stenosis (RAS) is an important cause of chronic kidney disease and secondary hypertension. In animal models, renal ischemia leads to downregulation of growth factor expression and loss of intrarenal microcirculation. However, little is known about the sequelae of large-vessel occlusive disease on the microcirculation within human kidneys. This study included five patients who underwent nephrectomy due to renovascular occlusion and seven nonstenotic discarded donor kidneys (four deceased donors). Micro-computed tomography was performed to assess microvascular spatial densities and tortuosity, an index of microvascular immaturity. Renal protein expression, gene expression and histology were studied in vitro using immunoblotting, polymerase chain reaction and staining. RAS demonstrated a loss of medium-sized vessels (0.2-0.3 mm)comparedwithdonorkidneys (P=0.037) and increased microvascular tortuosity. RAS kidneys had greater protein expression of angiopoietin-1, hypoxia-inducible factor-1α and thrombospondin-1 but lower protein expression of vascular endothelial growth factor (VEGF) than donor kidneys. Renal fibrosis, loss of peritubular capillaries (PTCs) and pericyte detachment were greater in RAS, yet they had more newly formed PTCs than donor kidneys. Therefore, our study quantified significant microvascular remodeling in the poststenotic human kidney. RAS induced renal microvascular loss, vascular remodeling and fibrosis. Despite downregulated VEGF, stenotic kidneys upregulated compensatory angiogenic pathways related to angiopoietin-1. These observations underscore the nature of human RAS as a microvascular disease distal to main vessel stenosis and support therapeutic strategies directly targeting the poststenotic kidney microcirculation in patients with RAS.

Med23 supports angiogenesis and maintains vascular integrity through negative regulation of angiopoietin2 expression

The mammalian Mediator complex consists of over 30 subunits and functions as a transcriptional hub integrating signaling for tissue-specific gene expression. Although the role of the Mediator complex in transcription has been extensively investigated, the functions of distinct Mediator subunits in development are not well understood. Here, we dissected the role of the Mediator subunit Med23 in mouse cardiovascular development. Endothelial-specific Med23 deletion caused embryonic lethality before embryonic day 13.5 (E13.5). The mutant embryos exhibited intracranial hemorrhage and diminished angiogenesis with dilated blood vessels in the head region, where the expression of Med23 was abundant at E10.5. Med23 deficiency impaired vasculogenesis in the head region and impeded retinal angiogenesis. Knocking down Med23 in human umbilical vein endothelial cells (HUVECs) resulted in angiogenic defects, recapitulating the vascular defects in Med23-mutant mice in a cell-autonomous manner. RNA sequencing in HUVECs indicated that Med23 deficiency resulted in the interruption of angiogenesis and the upregulation of angiopoietin2 (Ang2), an inducing factor for vascular network instability. Inhibition of Ang2 partially rescued angiogenic sprouting and lumen dilation defects in tube formation assays. Collectively, our findings demonstrate that Med23 promotes angiogenesis and maintains vascular integrity, in part by suppressing Ang2 signaling.

MG53 represses high glucose-induced inflammation and angiogenesis in human retinal endothelial cells by repressing the EGR1/STAT3 axis

Background Diabetic retinopathy (DR) is a vascular complication of diabetes mellitus that leads to visual injury and blindness. Both angiogenesis and inflammation play an important role in the pathogenesis of DR. Here we aimed to explore the mechanisms of mitsugumin 53 (MG53) in ameliorating the dysfunction induced by high glucose (HG) in humans retinal microvascular endothelial cells (HRECs). Methods HRECs were subjected to HG in the presence or absence of MG53 overexpression. The effect of MG53 on cell viability and inflammatory response in HG-treated HRECs was measured using the Cell Counting Kit-8 and ELISAs, respectively. Expression of MG53, EGR1, p-STAT3, FGF2, TGFB1, and Angiopoietin-1 in HG-treated HRECs was quantified by western blot or quantitative real-time polymerase chain reaction. Results HG significantly downregulated MG53 in HRECs, which reduced cell viability while inducing angiogenesis and inflammatory response. Upregulation of MG53 reversed these effects of HG. MG53 directly interacted with EGR1 and repressed its expression, which decreased phosphorylation of STAT3 and downregulated FGF2, TGFB1, and Angiopoietin-1. EGR1 up-regulation or STAT3 activation antagonized the protective effects of MG53. Conclusion MG53 alleviates HG-induced dysfunction in HRECs by repressing EGR1/STAT3 signaling. Thereby MG53 may have therapeutic potential in DR.

Topical Application of Antrodia cinnamomea Ointment in Diabetic Wound Healing.

The number of diagnosed diabetic patients is increasing worldwide. Many people with diabetes develop wounds that are slow to, or never, heal, which can lead to serious health issues. Diabetes causes long-term excessive blood glucose buildup in human body, which leads to an over-reactive inflammatory response and excessive oxidative stress. As a result, varied wound healing effects were observed according to different circumstances and stage of healing. We used two diabetic wound animal models to analyze the wound healing effect of Antrodia cinnamomea ointment in either topical application and/or oral administration, and explored its mechanism by Western blot analysis. The results showed that topical Antrodia cinnamomea treatment can significantly promote wound healing. The increased expressions of angiopoietin 1 and angiopoietin 2 protein and reduction of CD68 expression were found around wound area. Simultaneous treatment of oral and topical Antrodia cinnamomea ointment did not show an accelerated healing effect in our animal model. This study is the first report to demonstrate the effect of topical application of Antrodia cinnamomea ointment on diabetic wounds healing, and its relationship with angiogenesis. This may also open a new field for future development and application of Taiwan Antrodia cinnamomea.

SiRNA knockdown of angiopoietin 2 significantly reduces neovascularization in diabetic rats

Diabetes is a disease that leads to proliferative diabetic retinopathy (PDR), which is associated with an increase of new vessels formation due to an overexpression of angiogenic factors, such as angiopoietin 2 (ANGPT2). The aim of this work was to design a siRNA targeting ANGPT2 to decrease the retinal neovascularization associated with PDR. Adult male Wistar rats weighing 325–375 g were used. Diabetes was induced by a single dose of streptozotocin (STZ, 60 mg/kg i.p.). The siRNAs were designed, synthesised, and administered intravitreally at the beginning of diabetes induction (t0), and after 4 weeks of diabetes evolution (t4), subsequently evaluated the retinal neovascularization (junctions and lacunarity) and ANGPT2 expression in the retina by RT-PCR, after 4 weeks of the siRNAs administration. The results showed that the administration of STZ produced significant increases in blood glucose levels, retinal neovascularization (augmented junctions and lower lacunarity), and ANGPT2 expression, while the administration of the ANGPT2-siRNAs at different groups (t0 and t4) reduces the junctions and increases the lacunarity in diabetic rats. Therefore, we conclude that the administration of siRNAs targeting ANGPT2 could be an option to decrease the retinal neovascularization associated with PDR and halt the progression of blindness caused by diabetes.

The Osteocyte Stimulated by Wnt Agonist SKL2001 Is a Safe Osteogenic Niche Improving Bioactivities in a Polycaprolactone and Cell Integrated 3D Module.

Finding and constructing an osteogenic microenvironment similar to natural bone tissue has always been a frontier topic in orthopedics. We found that osteocytes are targeting cells controlling bone anabolism produced by PTH (JBMR 2017, PMID: 27704638), and osteocytes with activated Wnt signaling orchestrate bone formation and resorption (PNAS 2015, PMID: 25605937). However, methods for taking advantage of the leading role of osteocytes in bone regeneration remain unexplored. Herein, we found that the osteocytes with SKL2001-activated Wnt signaling could be an osteogenic microenvironment (SOOME) which upregulates the expression of bone transcription factor Runx2 and Bglap and promotes the differentiation of bone marrow stromal cell ST2 into osteoblasts. Interestingly, 60 μM SKL2001 treatment of osteocytic MLO-Y4 for 24 h maintained Wnt signaling activation for three days after removal, which was sufficient to induce osteoblast differentiation. Triptonide, a Wnt inhibitor, could eliminate this differentiation. Moreover, on day 5, the Wnt signaling naturally decreased to the level of the control group, indicating that this method of Wnt-signaling induction is safe to use. We quickly verified in vivo function of SOOME to a good proximation in 3D bioprinted modules composed of reciprocally printed polycaprolactone bundles (for support) and cell bundles (for bioactivity). In the cell bundles, SOOME stably supported the growth and development of ST2 cells, the 7-day survival rate was as high as 91.6%, and proliferation ability increased linearly. Similarly, SOOME greatly promoted ST2 differentiation and mineralization for 28 days. In addition, SOOME upregulated the expression of angiopoietin 1, promoted endothelial cell migration and angiogenesis, and increased node number and total length of tubes and branches. Finally, we found that the function of SOOME could be realized through the paracrine pathway. This study reveals that osteocytes with Wnt signaling activated by SKL2001 are a safe osteogenic microenvironment. Both SOOME itself and its cell-free culture supernatant can improve bioactivity for osteoblast differentiation, with composite scaffolds especially bearing application value.

Plasma angiopoietin 2 as a novel prognostic biomarker in alcohol-related cirrhosis and hepatitis

Background and aimSevere alcoholic hepatitis (SAH), the most florid form of alcohol-related liver disease (ALD), has a mortality rate of 16% at 28 days. The angiopoietin-Tie 2 system regulates angiogenesis and inflammation, both of which are implicated in the pathogenesis of ALD. This study examined plasma and hepatic gene expression of angiopoietin 1 (ANG1) and angiopoietin 2 (ANG2) in patients with SAH and ALD and investigated their roles as prognostic biomarkers. MethodsA case-control study was performed measuring plasma levels of ANG1 and ANG2 by enzyme-linked immunosorbent assay (ELISA) from 30 patients with SAH (Maddrey's discriminant function ≥32), 32 patients with ALD cirrhosis and 15 healthy controls (HC). RNA sequencing for ANG1, ANG2, TIE1 (codes for Tie1 receptor) and TEK (codes for Tie2 receptor) gene expression from a separate cohort study of 79 patients was also performed. ResultsPlasma levels of ANG1 were lower (P = 0.010) and ANG2 were higher (P < 0.0001) in patients with ALD/SAH compared to HC. The ANG2: ANG1 ratio was higher in those with ALD/SAH compared to HC (P < 0.0001). ANG2 levels were the highest in patients who developed sepsis (P = 0.030) and those dying within 90 days (P = 0.020). ANG2 levels correlated positively with model for end-stage liver disease (MELD) score (r = 0.30, P = 0.020), Child-Pugh score (r = 0.38, P = 0.003), international normalized ratio (r = 0.41, P = 0.001) and white blood cell count (r = 0.28, P = 0.040) and inversely correlated with albumin (r = −0.26, P = 0.040).ANG1 gene expression from liver biopsies was higher in SAH than that in HC (P < 0.0001), and greater in severe disease (P < 0.0001). ANG2 gene expression trended towards being lower in SAH than that in HC (P = 0.070) though was upregulated in severe disease (P = 0.0003). ConclusionsPlasma ANG2 is raised in SAH and ALD and could be useful as a prognostic biomarker in this patient population.

Increasing angiotensin-converting enzyme (ACE) 2/ACE axes ratio alleviates early pulmonary vascular remodeling in a porcine model of acute pulmonary embolism with cardiac arrest.

Acute pulmonary embolism (APE) with cardiac arrest (CA) is characterized by high mortality in emergency due to pulmonary arterial hypertension (PAH). This study aims to determine whether early pulmonary artery remodeling occurs in PAH caused by massive APE with CA and the protective effects of increasing angiotensin-converting enzyme (ACE) 2-angiotensin (Ang) (1-7)-Mas receptor axis and ACE-Ang II-Ang II type 1 receptor (AT1) axis (ACE2/ACE axes) ratio on pulmonary artery lesion after return of spontaneous circulation (ROSC). To establish a porcine massive APE with CA model, autologous thrombus was injected into the external jugular vein until mean arterial pressure dropped below 30 mmHg (1 mmHg=0.133 kPa). Cardiopulmonary resuscitation and thrombolysis were delivered to regain spontaneous circulation. Pigs were divided into four groups of five pigs each: control group, APE-CA group, ROSC-saline group, and ROSC-captopril group, to examine the endothelial pathological changes and expression of ACE2/ACE axes in pulmonary artery with or without captopril. Histological analysis of samples from the APE-CA and ROSC-saline groups showed that pulmonary arterioles were almost completely occluded by accumulated endothelial cells. Western blotting analysis revealed a decrease in the pulmonary arterial ACE2/ACE axes ratio and increases in angiopoietin-2/angiopoietin-1 ratio and expression of vascular endothelial growth factor (VEGF) in the APE-CA group compared with the control group. Captopril significantly suppressed the activation of angiopoietin-2/angiopoietin-1 and VEGF in plexiform lesions formed by proliferative endothelial cells after ROSC. Captopril also alleviated endothelial cell apoptosis by increasing the B-cell lymphoma-2 (Bcl-2)/Bcl-2-associated X (Bax) ratio and decreasing cleaved caspase-3 expression. Increasing the ACE2/ACE axes ratio may ameliorate pulmonary arterial remodeling by inhibiting the apoptosis and proliferation of endothelial cells after ROSC induced by APE.

Low Dose Chronic Angiotensin II Induces Selective Senescence of Kidney Endothelial Cells.

Angiotensin II can cause oxidative stress and increased blood pressure that result in long term cardiovascular pathologies. Here we evaluated the contribution of cellular senescence to the effect of chronic exposure to low dose angiotensin II in a model that mimics long term tissue damage. We utilized the INK-ATTAC (p16Ink4a–Apoptosis Through Targeted Activation of Caspase 8) transgenic mouse model that allows for conditional elimination of p16Ink4a -dependent senescent cells by administration of AP20187. Angiotensin II treatment for 3 weeks induced ATTAC transgene expression in kidneys but not in lung, spleen and brain tissues. In the kidneys increased expression of ATM, p15 and p21 matched with angiotensin II induction of senescence-associated secretory phenotype genes MMP3, FGF2, IGFBP2, and tPA. Senescent cells in the kidneys were identified as endothelial cells by detection of GFP expressed from the ATTAC transgene and increased expression of angiopoietin 2 and von Willebrand Factor, indicative of endothelial cell damage. Furthermore, angiotensin II induced expression of the inflammation-related glycoprotein versican and immune cell recruitment to the kidneys. AP20187-mediated elimination of p16-dependent senescent cells prevented physiologic, cellular and molecular responses to angiotensin II and provides mechanistic evidence of cellular senescence as a driver of angiotensin II effects.

Endothelial Dysfunction in Fabry Disease Is Related to Glycocalyx Degradation.

Fabry disease (FD) is an X-linked multisystemic lysosomal storage disease due to a deficiency of α-galactosidase A (GLA/AGAL). Progressive cellular accumulation of the AGAL substrate globotriaosylceramide (Gb3) leads to endothelial dysfunction. Here, we analyzed endothelial function in vivo and in vitro in an AGAL-deficient genetic background to identify the processes underlying this small vessel disease. Arterial stiffness and endothelial function was prospectively measured in five males carrying GLA variants (control) and 22 FD patients under therapy. AGAL-deficient endothelial cells (EA.hy926) and monocytes (THP1) were used to analyze endothelial glycocalyx structure, function, and underlying inflammatory signals. Glycocalyx thickness and small vessel function improved significantly over time (p<0.05) in patients treated with enzyme replacement therapy (ERT, n=16) and chaperones (n=6). AGAL-deficient endothelial cells showed reduced glycocalyx and increased monocyte adhesion (p<0.05). In addition, increased expression of angiopoietin-2, heparanase and NF-κB was detected (all p<0.05). Incubation of wild-type endothelial cells with pathological globotriaosylsphingosine concentrations resulted in comparable findings. Treatment of AGAL-deficient cells with recombinant AGAL (p<0.01), heparin (p<0.01), anti-inflammatory (p<0.001) and antioxidant drugs (p<0.05), and a specific inhibitor (razuprotafib) of angiopoietin-1 receptor (Tie2) (p<0.05) improved glycocalyx structure and endothelial function in vitro. We conclude that chronic inflammation, including the release of heparanases, appears to be responsible for the degradation of the endothelial glycocalyx and may explain the endothelial dysfunction in FD. This process is partially reversible by FD-specific and anti-inflammatory treatment, such as targeted protective Tie2 treatment.

BMAL1 may be involved in angiogenesis and peritumoral cerebral edema of human glioma by regulating VEGF and ANG2.

The rhythm gene BMAL1 (Brain and Muscle ARNT-Like 1) may play an important role in glioma tolerance for anti-angiogenesis therapy. In humans with glioma of different pathological grades, BMAL1 expression was significantly different, and the expression of ANG2 (Angiopoietin 2) and VEGF (Vascular endothelial growth factor) was positively correlated with the expression of BMAL1. Additionally, BMAL1 expression is positively correlated with the microvascular density and peritumoral edema of glioma. According to in vitro experiments, silencing the expression of BMAL1 in primary glioma cells results in a decrease in the expression of VEGF. In contrast, overexpression of BMAL1 promotes the expression of ANG2 and VEGF via HIF-1a pathway. Therefore, BMAL1 likely participates in the angiogenesis of glioma by modulating ANG2 and VEGF expression, alters the therapeutic effect of anti-angiogenic treatments, and promotes peritumoral brain edema of glioma.

MALAT1 improves functional recovery after traumatic brain injury through promoting angiogenesis in experimental mice

As a highly evolutionary conserved lncRNA, MALAT1 was first demonstrated to associate with metastasis of lung tumor by promoting angiogenesis. Activated vasculature was recently indicated to assist neurogenesis by secreting neurotrophic factor Ang1 (Angiopoietin-1). The purpose of this study is to investigate the potential role of MALAT1 in angiogenesis following traumatic brain injury (TBI). Adult male mice were subjected to controlled cortical impact (CCI) and brain microvascular endothelial cells were exposed to oxygen-glucose deprivation (OGD). MALAT1 RNA levels were quantified by qRT-PCR in different cells of CNS and located by RNA-FISH. Angiogenesis were measured by cell viability, migration assay, tube formation assay in vitro, and immunohistochemistry in vivo. Expression of Angiopoietin-1 was assessed by Western blot. Neurological functions were performed by NSS, Wire grip and MWM tests. Our results indicated that 1) MALAT1 RNA was localized in cerebral endothelium, enhanced by OGD stimuli. 2) Inhibition of MALAT1 by siRNA suppressed angiogenesis, as indicated by endothelial viability, tube formation, migration, and functional vessel density. 3) MALAT1 inhibition further decreased Ang1 expression in the endothelium. 4) Mice with MALAT1 inhibition exhibited worse behavioral performances (NSS, wire grip, Morris water maze), as compared to control. MALAT1 could promote angiogenesis, subsequently contributing to the Ang1 synthesis from active vasculature. It may eventually benefit to functional recovery following TBI.

Role of Proangiogenic Tyrosine Kinase with Immunoglobulin and Endothelial Growth Factor Homology Domains 2 Expressing Monocytes in Chronic Lymphocytic Leukemia

Background: Globally, highest hematologic malignancy in prevalence is considered chronic lymphocytic leukemia (CLL). The expression of angiopoietin-2 (Ang2) and tyrosine kinase with immunoglobulin and endothelial growth factor homology domains (Tie1), two critical components of the Ang-Tie2 pro-angiogenic pathway, in CLL cells has been demonstrated. Objective: Clarification of Tie2-expressing monocytes’ (TEMs) involvement in the pathophysiology of CLL is the goal of this study. Patients and Methods: The study was case control, which was performed on 21 CLL patients; their age ranged from 46 to 71 with a mean of 58.2 ± 6.9, in addition to 21 age and sex matched healthy control subjects. Full medical histories, clinical examinations, and laboratory tests were conducted on all individuals. The percentage of TEMs in peripheral blood was determined by flow cytometry and their phenotypic characteristics defined as CD14+/CD16+/Tie-2+ cells. Results: Compared to the control group, there was a statistically significant increase in TEMs in the cases group. Among the cases group there was a statistical significant increase in LDH, uric acid, WBCs, reticulocyte, CD 38 β2 microglobulin and TEMS and statistical significant decrease in Hb with increase Binet stage. There was a statistical significant +ve correlation between TEMs and LDH, WBCs, reticulocytes, CD38 and β2 microglobulin. Also, there was a statistical significant negative correlation between TEMs and Hb and platelets count among the cases group. TEMs percentage had sensitivity, specificity and accuracy (100%) in diagnosis of leukemia at cut off > 20.95%. Conclusion: TEMs could be a part of CLL pathogenesis which can be a predictor of disease progression alongside with other prognostic indicators.

Apelin Promotes Endothelial Progenitor Cell Angiogenesis in Rheumatoid Arthritis Disease via the miR-525-5p/Angiopoietin-1 Pathway.

Angiogenesis is a critical process in the formation of new capillaries and a key participant in rheumatoid arthritis (RA) pathogenesis. The adipokine apelin (APLN) plays critical roles in several cellular functions, including angiogenesis. We report that APLN treatment of RA synovial fibroblasts (RASFs) increased angiopoietin-1 (Ang1) expression. Ang1 antibody abolished endothelial progenitor cell (EPC) tube formation and migration in conditioned medium from APLN-treated RASFs. We also found significantly higher levels of APLN and Ang1 expression in synovial fluid from RA patients compared with those with osteoarthritis. APLN facilitated Ang1-dependent EPC angiogenesis by inhibiting miR-525-5p synthesis via phospholipase C gamma (PLCγ) and protein kinase C alpha (PKCα) signaling. Importantly, infection with APLN shRNA mitigated EPC angiogenesis, articular swelling, and cartilage erosion in ankle joints of mice with collagen-induced arthritis. APLN is therefore a novel therapeutic target for RA.