Advancement in the research on vascular endothelial growth inhibitor (VEGI)

Homeostatic Regulation of Pro-Angiogenic and Anti-Angiogenic Proteins via Hedgehog, Notch Grid, and Ephrin Signaling in Tibial Dyschondroplasia

Precise coupling of two fundamental mechanisms, chondrogenesis and osteogenesis via angiogenesis, plays a crucial role during rapid proliferation of growth plates, and alteration in their balance might lead to pathogenic conditions. Tibial dyschondroplasia (TD) is characterized by an avascular, non-mineralized, jade-white "cartilaginous wedge" with impaired endochondral ossification and chondrocyte proliferation at the proximal end of a tibial bone in rapidly growing poultry birds. Developing vascular structures are dynamic with cartilage growth and are regulated through homeostatic balance among pro and anti-angiogenic proteins and cytokines. Pro-angiogenic factors involves a wide spectrum of multifactorial mitogens, such as vascular endothelial growth factors (VEGF), platelet-derived growth factors (PDGF), basic fibroblast growth factor (bFGF), placental growth factors, transforming growth factor-β (TGF-β), and TNF-α. Considering their regulatory role via the sonic hedgehog, notch-gridlock, and ephrin-B2/EphB4 pathways and inhibition through anti-angiogenic proteins like angiostatin, endostatin, decoy receptors, vasoinhibin, thrombospondin, PEX, and troponin, their possible role in persisting inflammatory conditions like TD was studied in the current literature review. Balanced apoptosis and angiogenesis are vital for physiological bone growth. Any homeostatic imbalance among apoptotic, angiogenetic, pro-angiogenic, or anti-angiogenic proteins ultimately leads to pathological bone conditions like TD and osteoarthritis. The current review might substantiate solid grounds for developing innovative therapeutics for diseases governed by the disproportion of angiogenesis and anti-angiogenesis proteins.

An Update on Novel Ocular Nanosystems with Possible Benefits in the Treatment of Corneal Neovascularization

Corneal neovascularization (CNV) is an ocular pathological change that results from an imbalance between angiogenic factors and antiangiogenic factors as a result of various ocular insults, including infection, inflammation, hypoxia, trauma, corneal degeneration, and corneal transplantation. Current clinical strategies for the treatment of CNV include pharmacological treatment and surgical intervention. Despite some degree of success, the current treatment strategies are restricted by limited efficacy, adverse effects, and a short duration of action. Recently, gene-based antiangiogenic therapy has become an emerging strategy that has attracted considerable interest. However, potential complications with the use of viral vectors, such as potential genotoxicity resulting from long-term expression and nonspecific targeting, cannot be ignored. The use of ocular nanosystems (ONS) based on nanotechnology has emerged as a great advantage in ocular disease treatment during the last two decades. The potential functions of ONS range from nanocarriers, which deliver drugs and genes to target sites in the eye, to therapeutic agents themselves. Various preclinical studies conducted to date have demonstrated promising results of the use of ONS in the treatment of CNV. In this review, we provide an overview of CNV and its current therapeutic strategies and summarize the properties and applications of various ONS related to the treatment of CNV reported to date. Our goal is to provide a comprehensive review of these considerable advances in ONS in the field of CNV therapy over the past two decades to fill the gaps in previous related reports. Finally, we discuss existing challenges and future perspectives of the use of ONS in CNV therapy, with the goal of providing a theoretical contribution to facilitate future practical growth in the area.

The essential anti-angiogenic strategies in cartilage engineering and osteoarthritic cartilage repair

In the cartilage matrix, complex interactions occur between angiogenic and anti-angiogenic components, growth factors, and environmental stressors to maintain a proper cartilage phenotype that allows for effective load bearing and force distribution. However, as seen in both degenerative disease and tissue engineering, cartilage can lose its vascular resistance. This vascularization then leads to matrix breakdown, chondrocyte apoptosis, and ossification. Research has shown that articular cartilage inflammation leads to compromised joint function and decreased clinical potential for regeneration. Unfortunately, few articles comprehensively summarize what we have learned from previous investigations. In this review, we summarize our current understanding of the factors that stabilize chondrocytes to prevent terminal differentiation and applications of these factors to rescue the cartilage phenotype during cartilage engineering and osteoarthritis treatment. Inhibiting vascularization will allow for enhanced phenotypic stability so that we are able to develop more stable implants for cartilage repair and regeneration.

Tumor necrosis factor ligand-related molecule 1A maintains blood-retinal barrier via modulating SHP-1-Src-VE-cadherin signaling in diabetic retinopathy

An impaired blood-retinal barrier (BRB) leads to diabetic macular edema (DME), which is a major complication of Diabetic retinopathy (DR). Mediators such as inflammation cause BRB breakdown. However, the explicit mechanism of its disruption is largely unknown. In this study, we identified tumor necrosis factor ligand-related molecule 1A (TL1A) as a crucial factor which protect retinal endothelial cells integrity in DR. By providing both human and mouse data, we show that TL1A is significantly decreased in the retinas of DME patients and diabetic rodents. We further demonstrate that the loss of TL1A accelerated diabetes-induced retinal barrier breakdown. TL1A supplementation protects the diabetic retina against BRB breakdown. Mechanistically, TL1A stabilize intracellular junctions and protect vascular integrity by blocking SHP1-Src-regulated VE-cadherin phosphorylation. Collectively, our findings reveal that loss of TL1A in the retina leads to increased vascular permeability in DR, and that TL1A treatment is of potential therapeutic interest for the treatment of DME.

VEGI downregulation is correlated with nodal metastasis and poor prognosis in lung adenocarcinoma

Although the incidence of lung cancer is increasing worldwide, the molecular mechanisms for its tumorigenesis, progression and prognosis remain unknown. As a member of the tumor necrosis factor superfamily, vascular endothelial growth inhibitor (VEGI) is involved in the development and progression of many malignant diseases. In the present study, the expression of VEGI and CD31 was examined via immunohistochemistry in non-small cell lung cancer (NSCLC) tissues obtained from 150 patients with NSCLC. The inhibitory effect of VEGI on tumor-associated blood vessel formation and growth was investigated by determining the relationship between VEGI protein expression and microvascular density (MVD). Prognostic significance was evaluated using the Kaplan-Meier method. VEGI expression was downregulated or lost in 68.7% (103/150) of patients with NSCLC, an effect that was more prevalent in adenocarcinoma (AC), 76.0% (57/75), than in squamous cell carcinoma, 61.3% (46/75). A significant negative correlation was indentified between VEGI expression and lymphovascular invasion (P=0.039) and lymph node metastasis (P=0.017) in AC tissue. Additionally, MVD was significantly lower in the VEGI-rich group compared with the VEGI-poor group. The downregulation of VEGI expression was also associated with poorer overall survival (P=0.011) in patients with AC. The present study therefore provides evidence that VEGI may be a new and effective prognostic marker of lung AC.

Tumour-associated macrophages as a novel target of VEGI-251 in cancer therapy

Tumour‐associated macrophages (TAMs), which possess M2‐like characters and are derived from immature monocytes in the circulatory system, represent a predominant population of inflammatory cells in solid tumours. TAM infiltration in tumour microenvironment can be used as an important prognostic marker in many cancer types and is a potential target for cancer prevention or treatment. VEGI‐251 not only is involved in the inhibition of tumour angiogenesis, but also participates in the regulation of host immunity. This work aimed to investigate the involvement of VEGI‐251 in the regulation of specific antitumour immunity. We found that recombinant human VEGI‐251(rhVEGI‐251) efficiently mediated the elimination of TAMs in tumour tissue in mice, and induced apoptosis of purified TAMs in vitro. During this process, caspase‐8 and caspase‐3 were activated, leading to PARP cleavage and apoptosis. Most importantly, we further elucidated the mechanism underlying VEGI‐251‐triggered TAM apoptosis, which suggests that ASK1, an intermediate component of the VEGI‐251, activates the JNK pathway via TRAF2 in a potentially DR3‐dependent manner in the process of TAM apoptosis. Collectively, our findings provide new insights into the basic mechanisms underlying the actions of VEGI‐251 that might lead to future development of antitumour therapeutic strategies using VEGI‐251 to target TAMs.

Intraocular tumour necrosis factor ligand related molecule 1 A links disease progression of proliferative diabetic retinopathy after primary vitrectomy

Tumour necrosis factor ligand related molecule 1 A (TL1A), a member of tumour necrosis factor superfamily, has been identified as a crucial regulator for vascular homeostasis and inflammation. However, the function of TL1A in diabetic retinopathy (DR) is largely unknown. This study aims to examine levels of TL1A in serum and intraocular fluid in patients with proliferative diabetic retinopathy (PDR), and to explore the correlation of intraocular TL1A with the prognosis of PDR progression after primary vitrectomy. Seventy-five patients (75 eyes) with PDR who underwent pars plana vitrectomy (PPV) and 19 patients (19 eyes) who received vitrectomy for idiopathic macular holes (IMH) as non-diabetic control group were enrolled in this prospective study. Serum, aqueous and vitreous fluid samples were collected during cataract and PPV surgery. Protein expressions of TL1A as well as other angiogenic and inflammatory cytokines in serum and intraocular fluid were measured. Correlations of intraocular TL1A concentrations with inflammatory cytokines were analyzed. We found both aqueous and vitreous TL1A levels were significantly higher in the PDR group than in control group (P_aqueous  = 0.026; P_vitreous <0.001). Angiogenic and inflammatory cytokines such as VEGF, IL-6, IL-8, MCP-1, MIP-1α, and MIP-1β were significantly higher in intraocular fluid in PDR group than in controls, which MCP-1 and MIP-1α showed positive correlation with intraocular TL1A levels. There is no significant difference in the levels of serum TL1A as well as other inflammatory cytokines between PDR patients and controls. Intraocular levels of TL1A were significantly lower in PDR progression group than in the stable group (P_aqueous <0.001; P_vitreous <0.001). Multivariate logistic regression analyses revealed that lower levels of intraocular TL1A was an important risk factor for predicting PDR progression after primary PPV (OR_aqueous  = 0.717, P_aqueous  = 0.001; OR_vitreous  = 0.684; P_vitreous  = 0.002). In conclusion, TL1A and multiple inflammatory cytokines were highly enriched in the intraocular fluid of PDR patients compared with the controls. Lower levels of intraocular TL1A were associated with development of PDR complications after primary PPV and might be used as prognostic factor in predicting the vitrectomy outcome in PDR patients.

TNFSF15 is likely a susceptibility gene for systemic lupus erythematosus

We aim to explore the correlation of TNFSF15 genetic polymorphisms with susceptibility to systemic lupus erythematosus (SLE). This study enrolled SLE patients and healthy individuals to detect three single nucleotide polymorphisms (SNPs) of TNFSF15 (rs3810936, rs6478108 and rs4979462) through using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to analyze the possible association of these three SNPs with the risk of SLE and the mRNA level of TNFSF15 was quantified by real-time PCR. The rs3810936 T allele carrier greatly decreased risk of SLE (OR = 0.620, 95% CI = 0.454-0.849, P = 0.003), while the risk of SLE for rs4979462 T allele carrier was significantly increased (OR = 1.66, 95% CI = 1.243-2.218, P < 0.001). The mRNA level of TNFSF15 was obviously higher in SLE patients, and specifically, the patients who carried the CC genotype of TNFSF15 rs3810936 had a higher TNFSF15 mRNA, but the rs4979462 CC genotype carriers appeared to be associated with the decreased TNFSF15 mRNA (all P < 0.05). Besides, the genotypes of rs3810936 and rs4979462 of TNFSF15 were significantly associated with butterfly rash, arthritis, serositis, renal nephritis, hematological disorder, immunological disorder and positive antinuclear antibody (ANA) of SLE patients (all P < 0.05). CCT and CTT haplotypes were risk factors of SLE, but CCC and TTT were protective factors of SLE (all P < 0.05). Logistic regression analysis showed that rs3810936 and rs4979462 of TNFSF15, histories of chilblain and wet living environment were independently associated with the risk of SLE (all P < 0.05).The current results suggested that TNFSF15 (rs3810936 and rs4979462) SNPs may confer susceptibility to SLE risk, which were significantly associated with the clinical phenotypes of SLE.

Vascular precursor cells in tissue injury repair

Vascular precursor cells include stem cells and progenitor cells giving rise to all mature cell types in the wall of blood vessels. When tissue injury occurs, local hypoxia and inflammation result in the generation of vasculogenic mediators which orchestrate migration of vascular precursor cells from their niche environment to the site of tissue injury. The intricate crosstalk among signaling pathways coordinates vascular precursor cell proliferation and differentiation during neovascularization. Establishment of normal blood perfusion plays an essential role in the effective repair of the injured tissue. In recent years, studies on molecular mechanisms underlying the regulation of vascular precursor cell function have achieved substantial progress, which promotes exploration of vascular precursor cell-based approaches to treat chronic wounds and ischemic diseases in vital organ systems. Verification of safety and establishment of specific guidelines for the clinical application of vascular precursor cell-based therapy remain major challenges in the field.

Antagonistic effects of endostatin-vascular endothelial growth inhibitor chimeric recombinant adenovirus on homocysteine-induced vascular endothelial cells injury in vitro and in vivo

BACKGROUND

The study is inclined to investigate the antagonistic effects of endostatin-vascular endothelial growth inhibitor chimeric recombinant adenovirus (Ad-hENDO-VEGI) on homocysteine (Hcy)-induced vascular endothelial cells (VECs) injury in vitro and in vivo.

METHODS

Human VECs cell line ECV304 was selected and infected with Ad-hENDO-VEGI. The LDH leakage, SOD activity, and MDA levels were measured by the automatic biochemical analyzer. Cell survival rate was counted by Trypanblau dying. The TNF-α and MCP-1 protein expressions were detected by ELISA assay. The protein expressions of fusion protein of Ad-hENDO-VEGI, nuclear factor kappa B p65 (NF-kappa B p65), and NF-kappa B inhibitor alpha (I-kappa B-α) were detected by Western blotting. A rat model of hyper-homocysteinemia was constructed. Thirty-six Wistar rats were randomly divided into 3 groups: the control group, the model group, and the Ad-hENDO-VEGI group. Serum Hcy levels in rats were measured with enzymatic cycling method. Endothelial vasodilation function was evaluated with the treatment of sodium nitroprusside and acetylcholine.

RESULTS

After Ad-hENDO-VEGI infection, high expressions (41 kD) of fusion proteins in ECV304 cells were observed. The injury severity of Hcy on ECV304 cells had a dose-dependent manner, and the injury reached a steady stage at 1.0 mmol/L. Thus, 1.0 mmol/L Hcy was selected for further experiments. With an increase of Ad-hENDO-VEGI in ECV304 cells after Hcy treatment, LDH leakage, MDA, TNF-α, MCP-1, and nuclear NF-kappa B p65 protein expression were gradually decreased, and cell survival rate, SOD activity, and I-kappa B-α protein expression were gradually increased. Compared with the control group, the model group had a higher Hcy level and attenuated vasodilator response. The Ad-hENDO-VEGI group exhibited a lower Hcy level and enhanced vasodilator response than the model group.

CONCLUSION

These results indicated that Ad-hENDO-VEGI could down-regulate NF-kappa B p65 expression and suppress inflammatory response, thereby alleviating Hcy-induced VECs injury.

Evaluation of (188)Re-labeled NGR-VEGI protein for radioimaging and radiotherapy in mice bearing human fibrosarcoma HT-1080 xenografts

Vascular endothelial growth inhibitor (VEGI) is an anti-angiogenic protein, which includes three isoforms: VEGI-174, VEGI-192, and VEGI-251. The NGR (asparagine-glycine-arginine)-containing peptides can specifically bind to CD13 (Aminopeptidase N) receptor which is overexpressed in angiogenic blood vessels and tumor cells. In this study, a novel NGR-VEGI fusion protein was prepared and labeled with (188)Re for radioimaging and radiotherapy in mice bearing human fibrosarcoma HT-1080 xenografts. Single photon emission computerized tomography (SPECT) imaging results revealed that (188)Re-NGR-VEGI exhibits good tumor-to-background contrast in CD13-positive HT-1080 tumor xenografts. The CD13 specificity of (188)Re-NGR-VEGI was further verified by significant reduction of tumor uptake in HT-1080 tumor xenografts with co-injection of the non-radiolabeled NGR-VEGI protein. The biodistribution results demonstrated good tumor-to-muscle ratio (4.98 ± 0.25) of (188)Re-NGR-VEGI at 24 h, which is consistent with the results from SPECT imaging. For radiotherapy, 18.5 MBq of (188)Re-NGR-VEGI showed excellent tumor inhibition effect in HT-1080 tumor xenografts with no observable toxicity, which was confirmed by the tumor size change and hematoxylin and eosin (H&E) staining of major mouse organs. In conclusion, these data demonstrated that (188)Re-NGR-VEGI has the potential as a theranostic agent for CD13-targeted tumor imaging and therapy.

In vivo NIRF imaging-guided delivery of a novel NGR-VEGI fusion protein for targeting tumor vasculature

Pathological angiogenesis is crucial in tumor growth, invasion and metastasis. Previous studies demonstrated that the vascular endothelial growth inhibitor (VEGI), a member of the tumor necrosis factor superfamily, can be used as a potent endogenous inhibitor of tumor angiogenesis. Molecular probes containing the asparagine-glycine-arginine (NGR) sequence can specifically bind to CD13 receptor which is overexpressed on neovasculature and several tumor cells. Near-infrared fluorescence (NIRF) optical imaging for targeting tumor vasculature offers a noninvasive method for early detection of tumor angiogenesis and efficient monitoring of response to anti-tumor vasculature therapy. The aim of this study was to develop a new NIRF imaging probe on the basis of an NGR-VEGI protein for the visualization of tumor vasculature. The NGR-VEGI fusion protein was prepared from prokaryotic expression, and its function was characterized in vitro. The NGR-VEGI protein was then labeled with a Cy5.5 fluorophore to afford Cy5.5-NGR-VEGI probe. Using the NIRF imaging technique, we visualized and quantified the specific delivery of Cy5.5-NGR-VEGI protein to subcutaneous HT-1080 fibrosarcoma tumors in mouse xenografts. The Cy5.5-NGR-VEGI probe exhibited rapid HT-1080 tumor targeting, and highest tumor-to-background contrast at 8 h post-injection (pi). Tumor specificity of Cy5.5-NGR-VEGI was confirmed by effective blocking of tumor uptake in the presence of unlabeled NGR-VEGI (20 mg/kg). Ex vivo NIRF imaging further confirmed in vivo imaging findings, demonstrating that Cy5.5-NGR-VEGI displayed an excellent tumor-to-muscle ratio (18.93 ± 2.88) at 8 h pi for the non-blocking group and significantly reduced ratio (4.92 ± 0.75) for the blocking group. In conclusion, Cy5.5-NGR-VEGI provided highly sensitive, target-specific, and longitudinal imaging of HT-1080 tumors. As a novel theranostic protein, Cy5.5-NGR-VEGI has the potential to improve cancer treatment by targeting tumor vasculature.

MicroRNA/mRNA profiling and regulatory network of intracranial aneurysm

Background

Intracranial aneurysm (IA) is one of the most lethal forms of cerebrovascular diseases characterized by endothelial dysfunction, vascular smooth muscle cell phenotypic modulation, inflammation and consequently loss of vessel cells and extracellular matrix degradation. Besides environmental factors, genetics seem to be a very important factor in the genesis of this disease. Previous mRNA expression studies revealed a large number of differentially expressed genes between IA and control tissue. However, microRNAs (miRNA), small non-coding RNAs which are post-transcriptional regulators of gene expression, have been barely studied. Studying miRNAs could provide a hypothetical mechanism underlying rupture of IA.

Methods

A microarray study was carried out to determine difference in microRNAs and mRNA between patients’ IA tissues and controls. Quantitative RT-PCR assay compared the expression level between two groups (14 IA domes vs. 14 controls) were used for validation. Validated miRNAs were analyzed using Ingenuity Pathway Analysis (IPA) to identify the networks and pathways.

Results

18 miRNAs were confirmed by qPCR to be robustly down-regulated in 14 ruptured IA patients including hsa-mir-133b, hsa-mir-133a, hsa-mir-1, hsa-mir-143-3p, hsa-mir-145-3p, hsa-mir-145-5p, hsa-mir-455-5p, hsa-mir-143-5p, hsa-mir-23b-3p etc., of which 11 miRNAs are clusters: hsa-mir-1/has-mir-133a, hsa-mir-143/hsa-mir-145, hsa-mir-23b/hsa-mir-24-1, and hsa-mir-29b-2/hsa-mir-29c. 12 predicted functions were generated using IPA which showed significant associations with migration of phagocytes, proliferation of mononuclear leukocytes, cell movement of mononuclear leukocytes, cell movement of smooth muscle cells etc.

Conclusion

These data support common disease mechanisms that may be under miRNA control and provide exciting directions for further investigations aimed at elucidating the miRNA mechanisms and targets that may yield new therapies for IA.

Expression and function of vascular endothelial growth inhibitor in aged porcine bladder detrusor muscle cells

Aging of the bladder detrusor muscle plays an important role in lower urinary tract symptoms in elderly people. Our previous work demonstrated that elderly patients have increased levels of vascular endothelial growth inhibitor (VEGI) in bladder tissue. Therefore, we hypothesized that VEGI may play a role in aging of the bladder detrusor muscle cells. This study aims to develop and characterize primary cultures of aged porcine bladder detrusor muscle cells in order to explore the expression and function of VEGI. Bladder samples from female pigs were divided into two groups: the aged group (Model) and the young group (Control). We confirmed β-galactosidase expression, a marker for senescence, in aged muscle cells (identified by α-smooth muscle actin (α-SMA) staining), but not in the young group. mRNA levels of VEGI-251 and death receptor 3 (DR3) were up-regulated (P < 0.05) and total cell protein levels of VEGI-251, DR3 and nuclear factor-kappa B [NF-κB (p65)], membrane protein levels of DR3, and nuclear protein levels of NF-κB (p65) were significantly higher (P < 0.01) in the Model cells compared to Control cells. In conclusion, we have established a method to culture aged detrusor muscle cells derived from porcine bladder. Higher levels of VEGI-251, DR3 and NF-κB (p65) were observed in the aged cells. VEGI-251 may function by increasing DR3 on cellular membranes and promoting the transfer of NF-κB into the nucleus. This suggests that VEGI may be a target for reversing the aging process of bladder detrusor muscle cells.