Endostatin Prevents Dietary-Induced Obesity by Inhibiting Adipogenesis and Angiogenesis

Unveiling the Regulatory Role of LncRNA MYU in Hypoxia-Induced Angiogenesis via the miR-23a-3p Axis in Endothelial Cells

Background: Angiogenesis is essential for various physiological and pathological processes, such as embryonic development and cancer cell proliferation, migration, and invasion. Long noncoding RNAs (lncRNAs) play pivotal roles in normal homeostasis and disease processes by regulating gene expression through various mechanisms, including competing endogenous RNAs (ceRNAs) of target microRNAs (miRNAs). The lncRNA MYU is known to promote prostate cancer proliferation via the miR-184/c-Myc regulatory axis and to be upregulated in vascular endothelial cells under hypoxic conditions, which often occurs in solid tumors. In the present study, we investigated whether MYU might affect cancer growth by regulating angiogenesis in vascular endothelial cells under hypoxia. Methods: The expression of MYU-regulated miR-23a-3p and interleukin-8 (IL-8) in HUVEC cell lines was examined using qRT-PCR. The CCK-8 assay, EdU assay, wound-healing assay, and tube-formation assay were used to assess the effects of MYU on cell proliferation, migration, and tube formation of HUVEC cells in vitro. The dual-luciferase reporter assay was performed to examine the effects of miR-23a-3p on MYU and IL-8 expression. Results: We found that the overexpression of MYU and knockdown of miR-23a-3p in human umbilical vein endothelial cells (HUVECs) under hypoxia promoted cell proliferation, migration, and tube formation. Mechanistically, MYU was shown to bind competitively to miR-23a-3p, thereby preventing miR-23a-3p binding to the 3' untranslated region of IL-8 mRNA. In turn, increased production of pro-angiogenic IL-8 promoted HUVEC proliferation, migration, and tube formation under hypoxia. Conclusion: This study identified a new role for lncRNA MYU as a ceRNA for miR-23a-3p and uncovered a novel MYU-miR-23a-3p-IL-8 regulatory axis for angiogenesis. MYU and/or miR-23a-3p may thus represent new targets for the treatment of hypoxia-related diseases by promoting angiogenesis.

Adipose tissue angiogenesis genes are down-regulated by grape polyphenols supplementation during a human overfeeding trial

The adaptive response to overfeeding is associated with profound modifications of gene expression in adipose tissue to support lipid storage and weight gain. The objective of this study was to assess in healthy lean men whether a supplementation with polyphenols could interact with these molecular adaptations. Abdominal subcutaneous adipose tissue biopsies were sampled from 42 subjects participating to an overfeeding protocol providing an excess of 50% of their total energy expenditure for 31 days, and who were supplemented with 2 g/day of grape polyphenols or a placebo. Gene expression profiling was performed by RNA sequencing. Overfeeding led to a modification of the expression of 163 and 352 genes in the placebo and polyphenol groups, respectively. The GO functions of these genes were mostly involved in lipid metabolism, followed by genes involved in adipose tissue remodeling and expansion. In response to overfeeding, 812 genes were differentially regulated between groups. Among them, a set of 41 genes were related to angiogenesis and were downregulated in the polyphenol group. Immunohistochemistry targeting PECAM1, as endothelial cell marker, confirmed reduced angiogenesis in this group. Finally, quercetin and isorhamnetin, two polyphenol species enriched in the plasma of the volunteers submitted to the polyphenols, were found to inhibit human umbilical vein endothelial cells migration in vitro. Polyphenol supplementation do not prevent the regulation of genes related to lipid metabolism in human adipose tissue during overfeeding, but impact the angiogenesis pathways. This may potentially contribute to a protection against adipose tissue expansion during dynamic phase of weight gain.

Adipose endothelial cells mastering adipose tissues metabolic fate

Dynamic communication within adipose tissue depends on highly vascularized structural characteristics to maintain systemic metabolic homoeostasis. Recently, it has been noted that adipose endothelial cells (AdECs) act as essential bridges for biological information transmission between adipose-resident cells. Hence, paracrine regulators that mediate crosstalk between AdECs and adipose stromal cells were summarized. We also highlight the importance of AdECs to maintain adipocytes metabolic homoeostasis by regulating insulin sensitivity, lipid turnover and plasticity. The differential regulation of AdECs in adipose plasticity often depends on vascular density and metabolic states. Although choosing pro-angiogenic or anti-angiogenic therapies for obesity is still a matter of debate in clinical settings, the growing numbers of drugs have been confirmed to play an anti-obesity effect by affecting vascularization. Pharmacologic angiogenesis intervention has great potential as therapeutic strategies for obesity.

Obesity: The Fat Tissue Disease Version of Cancer

Obesity is a disease with high potential for fatality. It perfectly fits the disease definition, as cancer does. This is because it damages body structure and functions, both mechanically and biologically, and alters physical, mental, and social health. In addition, it shares many common morbid characteristics with the most feared disease, cancer. For example, it is influenced by a sophisticated interaction between a person’s genetics, the environment, and an increasing number of other backgrounds. Furthermore, it displays abnormal cell growth and proliferation events, only limited to white fat, resulting in adipose tissue taking up an increasing amount of space within the body. This occurs through fat “metastases” and via altered signaling that further aggravates the pathology of obesity by inducing ubiquitous dishomeostasis. These metastases can be made graver by angiogenesis, which might boost diseased tissue growth. More common features with cancer include its progressive escalation through different levels of severity and its possibility of re-onset after recovery. Despite all these similarities with cancer, obesity is substantially less agitating for most people. Thus, the ideas proposed herein could have utility to sensitize the public opinion about the hard reality of obesity. This is increasingly needed, as the obesity pandemic has waged a fierce war against our bodies and society in general, while there is still doubt about whether it is a real disease or not. Hence, raising public consciousness to properly face health issues is crucial to improving our health instead of gaining weight unhealthily. It is obviously illogical to fight cancer extremely seriously on the one hand and to consider dying with obesity as self-inflicted on the other. In fact, obesity merits a top position among the most lethal diseases besides cancer.

Effect of Weight Loss Surgery on Biomarkers of Angiogenesis in Obese Patients

BACKGROUND

The present study aims to clarify the effects of weight loss on biomarkers associated with angiogenesis in patients who underwent laparoscopic sleeve gastrectomy (SG) or adjustable gastric banding (LAGB) in the 12-month follow-up study.

MATERIALS AND METHODS

We studied 24 obese patients who underwent laparoscopic weight loss surgery, 13 of whom underwent SG and 11 of whom underwent LAGB. We evaluated the circulating level of angiogenesis biomarkers preoperatively and 12 months after surgery.

RESULTS

Before surgery, the following angiogenic circulating factors were significantly higher than those of healthy subjects: angiopoietin 2 (ANG-2) (p < .05), granulocyte colony-stimulating factor (G-CSF) (p < .05), hepatocyte growth factor (HGF) (p < .01), platelet endothelial cell adhesion molecule (PECAM-1) (p < .01), and vascular endothelial growth factor (VEGF) (p < .05). The following angiogenesis biomarkers decreased significantly after weight loss compared with their baseline values: ANG-2 (p < .05), follistatin (p < .05), HGF (p < .01), PECAM-1 (p < .01), and VEGF (p < .05). There were no significant differences in the circulating levels of angiogenesis biomarkers between individuals who underwent SG and those who underwent LAGB; however, HGF, PECAM-1, and VEGF tended to be lower after SG. %BMI correlated negatively with HGF, PECAM-1, and VEGF. A similar significant negative correlation was found for %WL and %EWL. WHR correlated with PDGF-B and VEGF.

CONCLUSIONS

We concluded that weight loss surgery induces the changes of circulating levels of angiogenesis biomarkers in obese patients. The changes in angiogenesis status in obese patients who lost weight after bariatric surgery depended on the amount of weight loss.

Angiogenesis in Adipose Tissue: The Interplay Between Adipose and Endothelial Cells

Obesity is a worldwide health problem, and as its prevalence increases, so does the burden of obesity-associated co-morbidities like type 2 diabetes or cardiovascular diseases (CVDs). Adipose tissue (AT) is an endocrine organ embedded in a dense vascular network. AT regulates the production of hormones, angiogenic factors, and cytokines. During the development of obesity, AT expands through the increase in fat cell size (hypertrophy) and/or fat cell number (hyperplasia). The plasticity and expansion of AT is related to its angiogenic capacities. Angiogenesis is a tightly orchestrated process, which involves endothelial cell (EC) proliferation, migration, invasion, and new tube formation. The expansion of AT is accelerated by hypoxia, inflammation, and structural remodeling of blood vessels. The paracrine signaling regulates the functional link between ECs and adipocytes. Adipocytes can secrete both pro-angiogenic molecules, e.g., tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), or vascular endothelial growth factor (VEGF), and anti-angiogenic factors, e.g., serpins. If the pro-angiogenic molecules dominate, the angiogenesis is dysregulated and the endothelium becomes dysfunctional. However, if anti-angiogenic molecules are overexpressed relative to the angiogenic regulators, the angiogenesis is repressed, and AT becomes hypoxic. Furthermore, in the presence of chronic nutritional excess, endothelium loses its primary function and contributes to the inflammation and fibrosis of AT, which increases the risk for CVDs. This review discusses the current understanding of ECs function in AT, the cross-talk between adipose and ECs, and how obesity can lead to its dysfunction. Understanding the interplay of angiogenesis with AT can be an approach to therapy obesity and obesity-related diseases such as CVDs.

Identification of the Myogenetic Oligodeoxynucleotides (myoDNs) That Promote Differentiation of Skeletal Muscle Myoblasts by Targeting Nucleolin

Herein we report that the 18-base telomeric oligodeoxynucleotides (ODNs) designed from the Lactobacillus rhamnosus GG genome promote differentiation of skeletal muscle myoblasts which are myogenic precursor cells. We termed these myogenetic ODNs (myoDNs). The activity of one of the myoDNs, iSN04, was independent of Toll-like receptors, but dependent on its conformational state. Molecular simulation and iSN04 mutants revealed stacking of the 13-15th guanines as a core structure for iSN04. The alkaloid berberine bound to the guanine stack and enhanced iSN04 activity, probably by stabilizing and optimizing iSN04 conformation. We further identified nucleolin as an iSN04-binding protein. Results showed that iSN04 antagonizes nucleolin, increases the levels of p53 protein translationally suppressed by nucleolin, and eventually induces myotube formation by modulating the expression of genes involved in myogenic differentiation and cell cycle arrest. This study shows that bacterial-derived myoDNs serve as aptamers and are potential nucleic acid drugs directly targeting myoblasts.

Regulation of Obesity by Antiangiogenic Herbal Medicines

Obesity is the result of an energy imbalance caused by an increased ratio of caloric intake to energy expenditure. In conjunction with obesity, related metabolic disorders, such as dyslipidemia, atherosclerosis, and type 2 diabetes, have become global health problems. Obesity progression is thought to be associated with angiogenesis and extracellular matrix (ECM) remodeling. Angiogenesis occurs in growing adult adipose tissues, which are similar to neoplastic tissues. Adipose tissue is highly vascularized, and each adipocyte is nourished by an extensive capillary network. Adipocytes produce proangiogenic factors, such as vascular endothelial growth factor A and fibroblast growth factor 2, which promote neovascularization within the adipose tissue. Furthermore, matrix metalloproteinases (MMPs), including MMP-2 and MMP-9, play important roles in adipose tissue development and microvessel maturation by modifying the ECM. Thus, modulation of angiogenesis and MMP activity provides a promising therapeutic approach for controlling human obesity and its related disorders. Over the past decade, there has been a great increase in the use of alternative treatments, such as herbal remedies, for these diseases. This review will focus on the role of angiogenesis in adipose tissue growth and the regulation of obesity by antiangiogenic herbal medicines.

Diagnostic Values of Inflammatory and Angiogenic Factors for Acute Joint Bleeding in Patients With Severe Hemophilia A

This study was conducted to assess the levels of inflammatory factors and angiogenic factors in patients with severe hemophilia A and evaluate their diagnostic values for acute joint bleeding. This study included a total of 144 patients with severe hemophilia A. Of them, 66 had acute joint bleeding. Ninety healthy volunteers were recruited as control. The levels of leukocytes, monocytes, platelets, hemoglobin, phagocyte migration inhibitory factor (MIF), plasminogen, fibrin/fibrinogen degradation products, d-dimer, and α2 antifibrinolytic enzyme were measured using hematology analyzer. Thrombomodulin, endostatin, intercellular adhesion molecule 1, and vascular endothelial growth factor (VEGF) were assessed using enzyme-linked immunosorbent assay. Logistic regression analysis was performed to analyze the factors affecting acute joint bleeding. Compared with healthy volunteers, the levels of leukocytes, C-reactive protein (CRP), MIF, and VEGF were significantly (P < .05) elevated in the patients with severe hemophilia A and were significantly higher in patients with joint bleeding than in patients with nonbleeding (P < .05). Multivariate analysis showed that CRP and VEGF were independent risk factors for acute joint bleeding (P < .05). The area under the curve, sensitivity, and specificity of CRP for the diagnosis of acute joint bleeding were 0.829, 88.43%, and 67.87%, respectively, and those of VEGF were 0.758, 82.8%, and 68.3%, respectively. The levels of inflammatory factors and angiogenesis factors are elevated in patients with severe hemophilia A and both CRP and VEGF are closely related to acute joint bleeding and may be used as potential biomarkers for predicting acute joint bleeding in patients with severe hemophilia A.

The Effects of a Novel Series of KTTKS Analogues on Cytotoxicity and Proteolytic Activity

KTTKS is a matrikine that originates from the proteolytic hydrolysis of collagen. This peptide stimulates ECM production and types I and III collagen expression in vitro. A more stable form of KTTKS is pal-KTTKS, known as Matrixyl^® or palmitoyl pentapeptide-3. A series of novel pentapeptides, analogues of KTTKS with the general formula X-KTTKS-OH(NH₂), where X = acetyl, lipoyl, palmitoyl residues, was designed and synthesized. Their effect on amidolytic activity of urokinase, thrombin, trypsin, plasmin, t-PA, and kallikrein were tested. Cytotoxic tests on fibroblasts, as well as collagen and DNA biosynthesis tests for selected peptides, were also carried out. The test results showed that the most active plasmin inhibitors were palmitoyl peptides, whether in acid or amide form. No biological effects of lysine modification to arginine in the synthesized peptides were found. None of the synthesized peptides was not cytotoxic on fibroblasts, and three of them showed cell growth. These three compounds showed no concentration-activity relationship in the collagen and DNA biosynthesis assays.

Loss of SRSF3 in Cardiomyocytes Leads to Decapping of Contraction-Related mRNAs and Severe Systolic Dysfunction

RATIONALE

RBPs (RNA binding proteins) play critical roles in the cell by regulating mRNA transport, splicing, editing, and stability. The RBP SRSF3 (serine/arginine-rich splicing factor 3) is essential for blastocyst formation and for proper liver development and function. However, its role in the heart has not been explored.

OBJECTIVE

To investigate the role of SRSF3 in cardiac function.

METHODS AND RESULTS

Cardiac SRSF3 expression was high at mid gestation and decreased during late embryonic development. Mice lacking SRSF3 in the embryonic heart showed impaired cardiomyocyte proliferation and died in utero. In the adult heart, SRSF3 expression was reduced after myocardial infarction, suggesting a possible role in cardiac homeostasis. To determine the role of this RBP in the adult heart, we used an inducible, cardiomyocyte-specific SRSF3 knockout mouse model. After SRSF3 depletion in cardiomyocytes, mice developed severe systolic dysfunction that resulted in death within 8 days. RNA-Seq analysis revealed downregulation of mRNAs encoding sarcomeric and calcium handling proteins. Cardiomyocyte-specific SRSF3 knockout mice also showed evidence of alternative splicing of mTOR (mammalian target of rapamycin) mRNA, generating a shorter protein isoform lacking catalytic activity. This was associated with decreased phosphorylation of 4E-BP1 (eIF4E-binding protein 1), a protein that binds to eIF4E (eukaryotic translation initiation factor 4E) and prevents mRNA decapping. Consequently, we found increased decapping of mRNAs encoding proteins involved in cardiac contraction. Decapping was partially reversed by mTOR activation.

CONCLUSIONS

We show that cardiomyocyte-specific loss of SRSF3 expression results in decapping of critical mRNAs involved in cardiac contraction. The molecular mechanism underlying this effect likely involves the generation of a short mTOR isoform by alternative splicing, resulting in reduced 4E-BP1 phosphorylation. The identification of mRNA decapping as a mechanism of systolic heart failure may open the way to the development of urgently needed therapeutic tools.

Difference in Serum Endostatin Levels in Diabetic Patients with Critical Limb Ischemia Treated by Autologous Cell Therapy or Percutaneous Transluminal Angioplasty

The aim of this study was to compare the serum levels of the anti-angiogenic factor endostatin (S-endostatin) as a potential marker of vasculogenesis after autologous cell therapy (ACT) versus percutaneous transluminal angioplasty (PTA) in diabetic patients with critical limb ischemia (CLI). A total of 25 diabetic patients with CLI treated in our foot clinic during the period 2008–2014 with ACT generating potential vasculogenesis were consecutively included in the study; 14 diabetic patients with CLI who underwent PTA during the same period were included in a control group in which no vasculogenesis had occurred. S-endostatin was measured before revascularization and at 1, 3, and 6 months after the procedure. The effect of ACT and PTA on tissue ischemia was confirmed by transcutaneous oxygen pressure (TcPO₂) measurement at the same intervals. While S-endostatin levels increased significantly at 1 and 3 months after ACT (both P < 0.001), no significant change of S-endostatin after PTA was observed. Elevation of S-endostatin levels significantly correlated with an increase in TcPO₂ at 1 month after ACT (r = 0.557; P < 0.001). Our study showed that endostatin might be a potential marker of vasculogenesis because of its significant increase after ACT in diabetic patients with CLI in contrast to those undergoing PTA. This increase may be a sign of a protective feedback mechanism of this anti-angiogenic factor.

Ginsenoside Rg1 inhibits dietary-induced obesity and improves obesity-related glucose metabolic disorders

Obesity and its consequent type 2 diabetes are significant threats to global health. Emerging evidence indicates that ginsenosides from ginseng (Panax ginseng) have anti-diabetic activity. We hypothesized that ginsenosides Rg1 could suppress dietary-induced obesity and improve obesity-related glucose metabolic disorders. Our results showed that ginsenoside Rg1 attenuated dietary-induced body weight gain and fat accumulation in white adipocyte tissue of mice fed a high-fat diet. Furthermore, we found that ginsenosides Rg1 not only decreased fasting glucose concentration and the 2-h postprandial glucose concentration, but also improved insulin resistance and glucose intolerance in those mice. Ginsenoside Rg1 also activated the AMPK pathway in vitro and in vivo and increased plasma membrane translocation of GLUT4 in C2C12 skeletal muscle cells. In conclusion, our observations suggested that ginsenoside Rg1 inhibited dietary-induced obesity and improved obesity-related insulin resistance and glucose intolerance by activation of the AMPK pathway.

Treatment with 20(S)-ginsenoside Rg3 reverses multidrug resistance in A549/DDP xenograft tumors

Multidrug resistance (MDR) is an obstacle for cancer chemotherapy. It was reported that 20(S)-ginsenoside Rg3 (hereafter Rg3) was able to regulate MDR in mouse leukemia cells. The present study investigated the effect of Rg3 on the MDR of A549 lung cancer cells. A cell viability assay revealed that Rg3 treatment increased cisplatin (DDP) cytotoxicity in DDP resistant A549 cells (A549/DDP). Furthermore, Rg3 increases the antitumor effect of DDP on A549/DDP xenograft mice. The expression of MDR-mediated proteins, including P-glycoprotein (P-gp), multidrug resistance-associated protein (MPR1) and lung resistance protein 1 (LPR1), was detected in tumor tissue of A549/DDP xenograft mice. The results revealed that Rg3 treatment inhibited the expression of these MDR-associated proteins. Additionally, technetium-99m labeled hexakis-2-methoxyisobutylisonitrile (^99mTc-MIBI) single-photon emission computed tomography was used to monitor the effect of Rg3 on cisplatin sensitivity of A549/DDP xenograft tumors. It was observed that uptake of ^99mTc-MIBI was increased by Rg3 treatment, which indicated that Rg3 is able to effectively enhance chemotherapy sensitivity of A549/DDP xenograft tumors. Taken together, these results revealed that Rg3 may be able to reverse MDR of lung cancer via the downregulation of P-gp, MPR1 and LPR1.

Endostatin: a promising biomarker in the cardiovascular continuum?

The current review article aims to provide an up-to-date summary of previous studies in humans that have reported the association between circulating endostatin levels and different cardiovascular phenotypes. We also aim to provide suggestions for future directions of future research evaluating endostatin as a clinically relevant cardiovascular biomarker. With a few exceptions, higher circulating levels of endostatin seem to reflect vascular and myocardial damage, and a worsened prognosis for cardiovascular events or mortality in individuals with hypertension, diabetes, kidney disease, cardiovascular disease, as well as in the general population. Circulating endostatin seems to be a promising biomarker for cardiovascular pathology, but there is not enough evidence to date to support the use of endostatin measurements in clinical practice.

E-M, an Engineered Endostatin with High ATPase Activity, Inhibits the Recruitment and Alternative Activation of Macrophages in Non-small Cell Lung Cancer

Endostatin recently was reported by our laboratory to possess ATPase activity that is indispensable for its anti-angiogenesis and anti-tumor effects. An engineered endostatin, E-M, which owns higher ATPase activity exhibits stronger inhibitory effects on angiogenesis. Tumor-associated macrophages (TAMs), especially M2-polarized TAMs, contribute to tumor progression by promoting tumor cell proliferation, metastasis, angiogenesis, and immunosuppression, thus emerging as crucial targets for therapeutic intervention. Endostatin reportedly modulated functions of TAMs, but the detailed mechanisms remain unclear. Here, in our study, we demonstrated that E-M exhibited stronger inhibitory effects on macrophages than endostatin and other low ATPase mutants, which indicates that the ATPase activity is required for the inhibitory effects of endostatin on TAMs. Moreover, we elucidated that endostatin co-receptor, nucleolin and integrin α5β1, overexpressed on the surface of M2 macrophages, facilitated the internalization of E-M via the caveolae/lipid raft- and clathrin-dependent pathways. E-M inhibited the migration of TAMs through blockade of p38 MAP kinase and Erk1/2 signaling pathways, and prevented the alternative activation of TAMs. As a result, TAM-induced tumor cell proliferation and angiogenic activities in vitro were dramatically suppressed by E-M. In a transplanted non-small cell lung cancer model, E-M remarkably decreased the density of intratumoral macrophages and blood vessels, leading to tumor regression. This study unravels a novel mechanism of endostatin on regulating TAM recruitment and polarization, and suggests that E-M is a remarkably promising and multifunctional anti-tumor agent.

Transcriptome profiling in preadipocytes identifies long noncoding RNAs as Sam68 targets

The KH-type RNA binding protein Sam68 is required for adipogenesis. We have previously shown that Sam68-deficient mice have a lean phenotype and are protected against dietary-induced obesity due to defects in mTOR and S6K1 alternative splicing. Herein we profiled the transcriptome of Sam68 wild type and deficient 3T3-L1 mouse preadipocytes. We identified 652 protein-coding genes and 9 ncRNAs that were significantly altered with the loss of Sam68. As expected, downregulated genes were significantly associated with GO terms linked to cell migration, motility, and fat cell differentiation, while upregulated genes were mostly associated with GO terms linked to neurogenesis. Of the lncRNAs, we identified Hotair, Mir155hg, as well as two new lncRNAs (SR-lncRNA-1 and SR-lncRNA-2) that were regulated by Sam68, and contained consensus Sam68 binding sites. RNA stability assays showed that Sam68-deficiency decreased the half-life of Hotair, and increased the half-lives of Mir155hg and SR-lncRNA-2, while the stability of SR-lncRNA-1 was unaffected. Depletion of Hotair and SR-lncRNA-1 in wild type 3T3-L1 cells led to defects in adipogenesis, whereas depletion of SR-lncRNA-2 in Sam68-deficient 3T3-L1 cells partially rescued the adipogenesis defect observed in these cells. Collectively, our findings define a new role for Sam68 as a regulator of lncRNAs during adipogenic differentiation.

Anti-angiogenic nanotherapy via active targeting systems to tumors and adipose tissue vasculature

Sophisticated drug delivery systems (DDS) are required for delivering drugs, especially macromolecules such as nucleic acids or proteins, to their sites of action. Therefore it is a prerequisite that future DDS are designed to selectively target a tissue. In this review, we focus on systems that actively target the vasculature in tumors or adipose tissues. For targeting tumor vasculatur, a new strategy referred to as dual-targeting is proposed that uses a combination of a receptor specific ligand and a cell penetrating peptide, which can induce the synergistic enhancement of tissue selectivity under in vivo conditions. A novel pH-sensitive cationic lipid was designed to enhance the endosomal release of encapsulated compounds such as siRNA as well as to improve the stability in blood circulation after intravenous administration. A cyclic RGD peptide is used as an active targeting ligand. For targeting adipose vasculature, prohibitin, which is expressed on the surface of adipose endothelial cells, was targeted with KGGRAKD peptides on the surface of PEGylated nanoparticles. Prohibitin targeted nanoparticles (PTNP) encapsulating Cytochrome c (CytC) can selectively target adipose vasculature by optimizing the lengths of the PEG linkers and can deliver CytC to adipose endothelial cells. PTNP can successfully induce anti-obese effects as well as apoptosis by delivering CytC to the cytosol in endothelial cells. Unexpectedly, the EPR (enhanced permeability and retention) effect, which is usually observed in tumor tissue, was also observed in the adipose vasculature, especially in obese mice, where PEGylated nanoparticles can pass through the endothelial barriers in adipose tissue. We believe that these achievements in active targeting will allow a greatly expanded use of DDS for nanomedicines.

Apelin/APJ system: A novel promising therapy target for pathological angiogenesis

Apelin is the endogenous ligand of the G protein-coupled receptor APJ. Both Apelin and APJ receptor are widely distributed in various tissues such as heart, brain, limbs, retina and liver. Recent research indicates that the Apelin/APJ system plays an important role in pathological angiogenesis which is a progress of new blood branches developing from preexisting vessels via sprouting. In this paper, we review the important role of the Apelin/APJ system in pathological angiogenesis. The Apelin/APJ system promotes angiogenesis in myocardial infarction, ischemic stroke, critical limb ischemia, tumor, retinal angiogenesis diseases, cirrhosis, obesity, diabetes and other related diseases. Furthermore, we illustrate the detailed mechanism of pathological angiogenesis induced by the Apelin/APJ system. In conclusion, the Apelin/APJ system would be a promising therapeutic target for angiogenesis-related diseases.

Glucagon-like peptide 1 improves insulin resistance in vitro through anti-inflammation of macrophages

Glucagon-like peptide 1 (GLP-1), a kind of gut hormone, is used in the treatment of type 2 diabetes (T2D). Emerging evidence indicates that GLP-1 has anti-inflammatory activity. Chronic inflammation in the adipose tissue of obese individuals is a cause of insulin resistance and T2D. We hypothesized that GLP-1 analogue therapy in patients with T2D could suppress the inflammatory response of macrophages, and therefore inhibit insulin resistance. Our results showed that GLP-1 agonist (exendin-4) not only attenuated macrophage infiltration, but also inhibited the macrophage secretion of inflammatory cytokines including TNF-β, IL-6, and IL-1β. Furthermore, we observed that lipopolysaccharide (LPS)-induced macrophage conditioned media could impair insulin-stimulated glucose uptake. This effect was compensated by treatment with the conditioned media from macrophages treated with the combination of LPS and exendin-4. It was also observed that exendin-4 directly inhibited the activation of NF-κB in macrophages. In conclusion, our results indicated that GLP-1 improved inflammatory macrophage-derived insulin resistance by inhibiting NF-κB pathway and secretion of inflammatory cytokines in macrophages. Furthermore, our observations suggested that the anti-inflammatory effect of GLP-1 on macrophages can contribute to GLP-1 analogue therapy of T2D.

The anti-angiogenic herbal extract from Melissa officinalis inhibits adipogenesis in 3T3-L1 adipocytes and suppresses adipocyte hypertrophy in high fat diet-induced obese C57BL/6J mice

ETHNOPHARMACOLOGICAL RELEVANCE

Melissa officinalis L. (Labiatae; lemon balm) has been used traditionally and contemporarily as an anti-stress herb. Current hypotheses suggest that not only chronic stress promotes angiogenesis, but angiogenesis also modulates adipogenesis and obesity. Because the herbal extract ALS-L1023 from M. officinalis L. (Labiatae; lemon balm) has an anti-angiogenic activity, we hypothesized that ALS-L1023 could inhibit adipogenesis and adipocyte hypertrophy.

MATERIALS AND METHODS

ALS-L1023 was prepared by a two-step organic solvent fractionation from M. officinalis. The effects of ALS-L1023 on adipogenesis in 3T3-L1 adipocytes and adipocyte hypertrophy in high fat diet (HFD)-fed obese mice were measured using in vivo and in vitro approaches.

RESULTS

ALS-L1023 inhibited angiogenesis in a dose-dependent manner in the HUVEC tube formation assay in vitro. Treatment of cells with ALS-L1023 inhibited lipid accumulation and adipocyte-specific gene expression caused by troglitazone or MDI differentiation mix. ALS-L1023 reduced mRNA expression of angiogenic factors (VEGF-A and FGF-2) and MMPs (MMP-2 and MMP-9) in differentiated cells. In contrast, mRNA levels of angiogenic inhibitors (TSP-1, TIMP-1, and TIMP-2) increased. Protease activity, as measured by zymography, showed that activity of MMP-2 and MMP-9 decreased in ALS-L1023-treated cells. ALS-L1023 also inhibited MMP-2 and MMP-9 reporter gene expression in the presence of the MMP inducer phorbol 12-myristate 13-acetate. An in vivo study showed that ALS-L1023 not only decreased adipose tissue mass and adipocyte size, but also reduced mRNA levels of adipose tissue angiogenic factors and MMPs in HFD-fed obese mice.

CONCLUSIONS

These results suggest that the anti-angiogenic herbal extract ALS-L1023 suppresses adipogenesis and adipocyte hypertrophy, and this effect may be mediated by inhibiting angiogenesis and MMP activities. Thus, by curbing adipogenesis, anti-angiogenic ALS-L1023 yields a possible therapeutic choice for the prevention and treatment of human obesity and its associated conditions.

Comparisons of biophysical properties and bioactivities of mono-PEGylated endostatin and an endostatin analog

Background

Endostatin (ES) is a well-established potent endogenous antiangiogenic factor. An ES variant, called zinc-binding protein-ES (ZBP-ES), is clinically available; however, its use is limited by rapid renal clearance and short residence time. PEGylation has been exploited to overcome these shortcomings, and mono-PEGylated ES (called M₂ES) as well as mono-PEGylated ZBP-ES (MZBP-ES) are developed in our study. This study aimed to compare the biophysical properties and biological effects of M₂ES and MZBP-ES to evaluate their druggability.

Methods

Circular dichroism and tryptophan emission fluorescence were used to monitor the conformational changes of M₂ES and MZBP-ES. Their resistance to trypsin digestion and guanidinium chloride (GdmCl)-induced unfolding was examined by Coomassie staining and tryptophan emission fluorescence, respectively. The biological effects of M₂ES and MZBP-ES on endothelial cell migration were evaluated using Transwell migration and wound healing assays, and the uptake of M₂ES and MZBP-ES in endothelial cells was also compared by Western blotting and immunofluorescence.

Results

Structural analyses revealed that M₂ES has a more compact tertiary structure than MZBP-ES. Moreover, M₂ES was more resistant to trypsin digestion and GdmCl-induced unfolding compared with MZBP-ES. In addition, although M₂ES and MZBP-ES showed comparable levels of inhibiting transwell migration and wound healing of endothelial cells, M₂ES displayed an increased ability to enter cells compared with MZBP-ES, possibly caused by the enhanced interaction with nucleolin.

Conclusions

M₂ES has a more compact tertiary structure, is more stable for trypsin digestion and GdmCl-induced unfolding, exhibits increased cellular uptake and shows equivalent inhibitory effects on cell migration relative to MZBP-ES, indicating that M₂ES is a more promising candidate for anticancer drug development compared with MZBP-ES.

Endostatin's emerging roles in angiogenesis, lymphangiogenesis, disease, and clinical applications

BACKGROUND

Angiogenesis is the process of neovascularization from pre-existing vasculature and is involved in various physiological and pathological processes. Inhibitors of angiogenesis, administered either as individual drugs or in combination with other chemotherapy, have been shown to benefit patients with various cancers. Endostatin, a 20-kDa C-terminal fragment of type XVIII collagen, is one of the most potent inhibitors of angiogenesis.

SCOPE OF REVIEW

We discuss the biology behind endostatin in the context of its endogenous production, the various receptors to which it binds, and the mechanisms by which it acts. We focus on its inhibitory role in angiogenesis, lymphangiogenesis, and cancer metastasis. We also present emerging clinical applications for endostatin and its potential as a therapeutic agent in the form a short peptide.

MAJOR CONCLUSIONS

The delicate balance between pro- and anti-angiogenic factors can be modulated to result in physiological wound healing or pathological tumor metastasis. Research in the last decade has emphasized an emerging clinical potential for endostatin as a biomarker and as a therapeutic short peptide. Moreover, elevated or depressed endostatin levels in diseased states may help explain the pathophysiological mechanisms of the particular disease.

GENERAL SIGNIFICANCE

Endostatin was once sought after as the 'be all and end all' for cancer treatment; however, research throughout the last decade has made it apparent that endostatin's effects are complex and involve multiple mechanisms. A better understanding of newly discovered mechanisms and clinical applications still has the potential to lead to future advances in the use of endostatin in the clinic.