Insulin-like growth factor binding protein-7 (IGFBP7) blocks vascular endothelial cell growth factor (VEGF)-induced angiogenesis in human vascular endothelial cells

Association of baseline and longitudinal changes in insulin-like growth factor-binding protein-7 with the risk of incident heart failure: Data from the PREVEND study

AIM

Senescence is a major risk factor for heart failure (HF), and insulin-like growth factor-binding protein-7 (IGFBP7) has been identified as an important senescence-inducing factor. The aim of this study was to examine the value of baseline and repeat IGFBP7 measurements in predicting future HF among community-dwelling Dutch adults from the Prevention of Renal and Vascular End-stage Disease (PREVEND) study.

METHODS AND RESULTS

Individuals without prevalent HF who attended PREVEND visits 2 and 4 median of 5.1 years apart (25th-75th percentile, 4.9-5.2) with measurements of IGFBP7 were included. We used Cox proportional hazards models to investigate the association between IGFBP7 and HF incidence. A total of 6125 participants attending visit 2 (mean ± standard deviation [SD] age 53.1 ± 12.2 years; 3151 [51.4%] men) were followed for a median of 8.4 (7.8-8.9) years, and 194 participants (3.2%) developed incident HF. Median baseline IGFBP7 concentration was 87.0 (75.1-97.3) ng/ml, and baseline IGFBP7 levels were significantly associated with risk for incident HF (HF risk factors adjusted hazard ratio [HR] per 1 SD change in log-transformed IGFBP7: 1.22, 95% confidence interval [CI] 1.03-1.46). Baseline IGFBP7 was also significantly associated with incident HF in individuals with N-terminal pro-B-type natriuretic peptide <125 ng/L. Among 3879 participants attending both visits 2 and 4 (mean ± SD age 57.5 ± 11.3 years; 1952 [50.3%] men), 93 individuals developed HF (after visit 4) during a median follow-up of 3.2 (2.8-3.9) years. Median increase in IGFBP7 concentration between visits was 0.68 (-7.09 to 8.36) ng/ml, and changes in IGFBP7 levels were significantly associated with risk for incident HF (HF risk factors adjusted HR per 1 SD change in log-transformed IGFBP7: 1.68, 95% CI 1.19-2.36).

CONCLUSIONS

Both baseline as well as repeat IGFBP7 measurements provide information about the risk of developing HF.

Early Injury Landscape in Vein Harvest by Single-Cell and Spatial Transcriptomics

BACKGROUND

Vein graft failure following cardiovascular bypass surgery results in significant patient morbidity and cost to the healthcare system. Vein graft injury can occur during autogenous vein harvest and preparation, as well as after implantation into the arterial system, leading to the development of intimal hyperplasia, vein graft stenosis, and, ultimately, bypass graft failure. Although previous studies have identified maladaptive pathways that occur shortly after implantation, the specific signaling pathways that occur during vein graft preparation are not well defined and may result in a cumulative impact on vein graft failure. We, therefore, aimed to elucidate the response of the vein conduit wall during harvest and following implantation, probing the key maladaptive pathways driving graft failure with the overarching goal of identifying therapeutic targets for biologic intervention to minimize these natural responses to surgical vein graft injury.

METHODS

Employing a novel approach to investigating vascular pathologies, we harnessed both single-nuclei RNA-sequencing and spatial transcriptomics analyses to profile the genomic effects of vein grafts after harvest and distension, then compared these findings to vein grafts obtained 24 hours after carotid-carotid vein bypass implantation in a canine model (n=4).

RESULTS

Spatial transcriptomic analysis of canine cephalic vein after initial conduit harvest and distention revealed significant enrichment of pathways (P<0.05) involved in the activation of endothelial cells (ECs), fibroblasts, and vascular smooth muscle cells, namely pathways responsible for cellular proliferation and migration and platelet activation across the intimal and medial layers, cytokine signaling within the adventitial layer, and ECM (extracellular matrix) remodeling throughout the vein wall. Subsequent single-nuclei RNA-sequencing analysis supported these findings and further unveiled distinct EC and fibroblast subpopulations with significant upregulation (P<0.05) of markers related to endothelial injury response and cellular activation of ECs, fibroblasts, and vascular smooth muscle cells. Similarly, in vein grafts obtained 24 hours after arterial bypass, there was an increase in myeloid cell, protomyofibroblast, injury response EC, and mesenchymal-transitioning EC subpopulations with a concomitant decrease in homeostatic ECs and fibroblasts. Among these markers were genes previously implicated in vein graft injury, including VCAN, FBN1, and VEGFC, in addition to novel genes of interest, such as GLIS3 and EPHA3. These genes were further noted to be driving the expression of genes implicated in vascular remodeling and graft failure, such as IL-6, TGFBR1, SMAD4, and ADAMTS9. By integrating the spatial transcriptomics and single-nuclei RNA-sequencing data sets, we highlighted the spatial architecture of the vein graft following distension, wherein activated and mesenchymal-transitioning ECs, myeloid cells, and fibroblasts were notably enriched in the intima and media of distended veins. Finally, intercellular communication network analysis unveiled the critical roles of activated ECs, mesenchymal-transitioning ECs, protomyofibroblasts, and vascular smooth muscle cells in upregulating signaling pathways associated with cellular proliferation (MDK [midkine], PDGF [platelet-derived growth factor], VEGF [vascular endothelial growth factor]), transdifferentiation (Notch), migration (ephrin, semaphorin), ECM remodeling (collagen, laminin, fibronectin), and inflammation (thrombospondin), following distension.

CONCLUSIONS

Vein conduit harvest and distension elicit a prompt genomic response facilitated by distinct cellular subpopulations heterogeneously distributed throughout the vein wall. This response was found to be further exacerbated following vein graft implantation, resulting in a cascade of maladaptive gene regulatory networks. Together, these results suggest that distension initiates the upregulation of pathological pathways that may ultimately contribute to bypass graft failure and presents potential early targets warranting investigation for targeted therapies. This work highlights the first applications of single-nuclei and spatial transcriptomic analyses to investigate venous pathologies, underscoring the utility of these methodologies and providing a foundation for future investigations.

Focused cancer pathway analysis revealed unique therapeutic targets in retinoblastoma

Retinoblastoma (RB) is a pediatric cancer of the eye that occurs in 1/15000 live births worldwide. Albeit RB is initiated by the inactivation of RB1 gene, the disease progression relies largely on transcriptional alterations. Therefore, evaluating gene expression is vital to unveil the therapeutic targets in RB management. In this study, we employed an RT2 Profiler™ PCR array for a focused analysis of 84 cancer-specific genes in RB. An interaction network was built with gene expression data to identify the dysregulated pathways in RB. The key transcript alterations identified in 13 tumors by RT2 Profiler™ PCR array was further validated in 15 tumors by independent RT-qPCR. Out of 84 cancer-specific genes, 68 were dysregulated in RB tumors. Among the 68 genes, 23 were chosen for further analysis based on statistical significance and abundance across multiple tumors. Pathway analysis of altered genes showed the frequent perturbations of cell cycle, angiogenesis and apoptotic pathways in RB. Notably, upregulation of MCM2, MKI67, PGF, WEE1, CDC20 and downregulation of COX5A were found in all the tumors. Western blot confirmed the dysregulation of identified targets at protein levels as well. These alterations were more prominent in invasive RB, correlating with the disease pathogenesis. Our molecular analysis thus identified the potential therapeutic targets for improving retinoblastoma treatment. We also suggest that PCR array can be used as a tool for rapid and cost-effective gene expression analysis.

CD93 maintains endothelial barrier function and limits metastatic dissemination

Compromised vascular integrity facilitates extravasation of cancer cells and promotes metastatic dissemination. CD93 has emerged as a target for antiangiogenic therapy, but its importance for vascular integrity in metastatic cancers has not been evaluated. Here, we demonstrate that CD93 participates in maintaining the endothelial barrier and reducing metastatic dissemination. Primary melanoma growth was hampered in CD93-/- mice, but metastatic dissemination was increased and associated with disruption of adherens and tight junctions in tumor endothelial cells and elevated expression of matrix metalloprotease 9 at the metastatic site. CD93 directly interacted with vascular endothelial growth factor receptor 2 (VEGFR2) and its absence led to VEGF-induced hyperphosphorylation of VEGFR2 in endothelial cells. Antagonistic anti-VEGFR2 antibody therapy rescued endothelial barrier function and reduced the metastatic burden in CD93-/- mice to wild-type levels. These findings reveal a key role of CD93 in maintaining vascular integrity, which has implications for pathological angiogenesis and endothelial barrier function in metastatic cancer.

Integrated single-nuclei and spatial transcriptomic analysis reveals propagation of early acute vein harvest and distension injury signaling pathways following arterial implantation

Background

Vein graft failure (VGF) following cardiovascular bypass surgery results in significant patient morbidity and cost to the healthcare system. Vein graft injury can occur during autogenous vein harvest and preparation, as well as after implantation into the arterial system, leading to the development of intimal hyperplasia, vein graft stenosis, and, ultimately, bypass graft failure. While previous studies have identified maladaptive pathways that occur shortly after implantation, the specific signaling pathways that occur during vein graft preparation are not well defined and may result in a cumulative impact on VGF. We, therefore, aimed to elucidate the response of the vein conduit wall during harvest and following implantation, probing the key maladaptive pathways driving graft failure with the overarching goal of identifying therapeutic targets for biologic intervention to minimize these natural responses to surgical vein graft injury.

Methods

Employing a novel approach to investigating vascular pathologies, we harnessed both single-nuclei RNA-sequencing (snRNA-seq) and spatial transcriptomics (ST) analyses to profile the genomic effects of vein grafts after harvest and distension, then compared these findings to vein grafts obtained 24 hours after carotid-cartoid vein bypass implantation in a canine model (n=4).

Results

Spatial transcriptomic analysis of canine cephalic vein after initial conduit harvest and distention revealed significant enrichment of pathways (P < 0.05) involved in the activation of endothelial cells (ECs), fibroblasts (FBs), and vascular smooth muscle cells (VSMCs), namely pathways responsible for cellular proliferation and migration and platelet activation across the intimal and medial layers, cytokine signaling within the adventitial layer, and extracellular matrix (ECM) remodeling throughout the vein wall. Subsequent snRNA-seq analysis supported these findings and further unveiled distinct EC and FB subpopulations with significant upregulation (P < 0.00001) of markers related to endothelial injury response and cellular activation of ECs, FBs, and VSMCs. Similarly, in vein grafts obtained 24 hours after arterial bypass, there was an increase in myeloid cell, protomyofibroblast, injury-response EC, and mesenchymal-transitioning EC subpopulations with a concomitant decrease in homeostatic ECs and fibroblasts. Among these markers were genes previously implicated in vein graft injury, including VCAN (versican), FBN1 (fibrillin-1), and VEGFC (vascular endothelial growth factor C), in addition to novel genes of interest such as GLIS3 (GLIS family zinc finger 3) and EPHA3 (ephrin-A3). These genes were further noted to be driving the expression of genes implicated in vascular remodeling and graft failure, such as IL-6, TGFBR1, SMAD4, and ADAMTS9. By integrating the ST and snRNA-seq datasets, we highlighted the spatial architecture of the vein graft following distension, wherein activated and mesenchymal-transitioning ECs, myeloid cells, and FBs were notably enriched in the intima and media of distended veins. Lastly, intercellular communication network analysis unveiled the critical roles of activated ECs, mesenchymal transitioning ECs, protomyofibroblasts, and VSMCs in upregulating signaling pathways associated with cellular proliferation (MDK, PDGF, VEGF), transdifferentiation (Notch), migration (ephrin, semaphorin), ECM remodeling (collagen, laminin, fibronectin), and inflammation (thrombospondin), following distension.

Conclusions

Vein conduit harvest and distension elicit a prompt genomic response facilitated by distinct cellular subpopulations heterogeneously distributed throughout the vein wall. This response was found to be further exacerbated following vein graft implantation, resulting in a cascade of maladaptive gene regulatory networks. Together, these results suggest that distension initiates the upregulation of pathological pathways that may ultimately contribute to bypass graft failure and presents potential early targets warranting investigation for targeted therapies. This work highlights the first applications of single-nuclei and spatial transcriptomic analyses to investigate venous pathologies, underscoring the utility of these methodologies and providing a foundation for future investigations.

Angiogenesis modulated by CD93 and its natural ligands IGFBP7 and MMRN2: a new target to facilitate solid tumor therapy by vasculature normalization

The tumor vasculature was different from the normal vasculature in both function and morphology, which caused hypoxia in the tumor microenvironment (TME). Previous anti-angiogenesis therapy had led to a modest improvement in cancer immunotherapy. However, antiangiogenic therapy only benefitted a few patients and caused many side effects. Therefore, there was still a need to develop a new approach to affect tumor vasculature formation. The CD93 receptor expressed on the surface of vascular endothelial cells (ECs) and its natural ligands, MMRN2 and IGFBP7, were now considered potential targets in the antiangiogenic treatment because recent studies had reported that anti-CD93 could normalize the tumor vasculature without impacting normal blood vessels. Here, we reviewed recent studies on the role of CD93, IGFBP7, and MMRN2 in angiogenesis. We focused on revealing the interaction between IGFBP7-CD93 and MMRN2-CD93 and the signaling cascaded impacted by CD93, IGFBP7, and MMRN2 during the angiogenesis process. We also reviewed retrospective studies on CD93, IGFBP7, and MMRN2 expression and their relationship with clinical factors. In conclusion, CD93 was a promising target for normalizing the tumor vasculature.

Low-affinity insulin-like growth factor binding protein 7 and its association with pulmonary arterial hypertension severity and survival

Insulin-like growth factor (IGF) binding proteins (IGFBPs) are a family of growth factor modifiers, some of which are known to be independently associated with pulmonary arterial hypertension (PAH) survival. IGF factor binding protein 7 (IGFBP7) is a unique low-affinity IGFBP that, independent of IGF, stimulates prostacyclin production. This study proposed to establish associations between IGFBP7 and PAH severity and survival, using enrollment and longitudinal samples. Serum IGFBP7 levels were significantly elevated in patients with PAH compared to controls. After adjusting for age and sex, logarithmic increases in IGFBP7 were associated with a 20 m shorter six-minute walk distance (6MWD; p < 0.001), a 2-3 mmHg higher mean right atrial pressure (p < 0.001 and 0.02), and a higher likelihood of a greater REVEAL 2.0 risk category placement (p < 0.001). Kaplan-Meier analysis demonstrated significantly decreased survival with IGFBP7 above the median and Cox multivariable analysis adjusted for age and sex, demonstrated higher serum IGFBP7 was an independent predictor of survival. Though the exact mechanism is still unknown, given IGFBP7's role as a prostacyclin stimulant, it has potential use as a therapeutic target for disease modulation.

Endothelial cell-leukemia interactions remodel drug responses, uncovering T-ALL vulnerabilities

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive and often incurable disease. To uncover therapeutic vulnerabilities, we first developed T-ALL patient-derived tumor xenografts (PDXs) and exposed PDX cells to a library of 433 clinical-stage compounds in vitro. We identified 39 broadly active drugs with antileukemia activity. Because endothelial cells (ECs) can alter drug responses in T-ALL, we developed an EC/T-ALL coculture system. We found that ECs provide protumorigenic signals and mitigate drug responses in T-ALL PDXs. Whereas ECs broadly rescued several compounds in most models, for some drugs the rescue was restricted to individual PDXs, suggesting unique crosstalk interactions and/or intrinsic tumor features. Mechanistically, cocultured T-ALL cells and ECs underwent bidirectional transcriptomic changes at the single-cell level, highlighting distinct "education signatures." These changes were linked to bidirectional regulation of multiple pathways in T-ALL cells as well as in ECs. Remarkably, in vitro EC-educated T-ALL cells transcriptionally mirrored ex vivo splenic T-ALL at single-cell resolution. Last, 5 effective drugs from the 2 drug screenings were tested in vivo and shown to effectively delay tumor growth and dissemination thus prolonging overall survival. In sum, we developed a T-ALL/EC platform that elucidated leukemia-microenvironment interactions and identified effective compounds and therapeutic vulnerabilities.

Retinal arterial macroaneurysms with supravalvular pulmonic stenosis syndrome can be associated with coronary and major systemic arterial disease

Purpose

To report novel life-threatening coronary and systemic arterial disease associated with Retinal Arterial Macroaneurysms with Supravalvular Pulmonic Stenosis (RAMSVPS) syndrome, previously known as Familial Retinal Arterial Macroaneurysms (FRAM).

Observations

A 29-years old woman with longstanding poor vision in her right eye presented with acute myocardial infarction and subclavian bruit. Her polyangiogram showed peculiar ostial coronary aneurysms, left anterior descending coronary artery stenosis, occlusion of the left subclavian artery, stenosis of both renal arteries, irregularities in the mesenteric artery and tapering of the aorta. Takayasu arteritis was initially presumed, however fundus examination revealed beading and macroaneurysms along major retinal arteries, intraretinal exudation and hemorrhages, retinal arterial sheathing and stenosis, Coats’-like features and submacular gliosis in the right eye, vitreous hemorrhage in the left eye, and persistent hyaloid artery remnant in both eyes. These features evoked RAMSVPS syndrome. Genetic testing identified the same homozygous IGFBP7 c.830-1G > A mutation reported with RAMSVPS syndrome, rectifying the systemic diagnosis.

Conclusion and importance

RAMSVPS syndrome can be associated with more life-threatening coronary and widespread major arterial disease than previously recognized. It is crucial for ophthalmologists to recognize RAMSVPS syndrome and refer patients for a thorough cardiovascular evaluation. Likewise, a careful retinal examination and the possibility of an IGFBP7 mutation should be considered in the setting of systemic arterial or cardiac disease.

Deconvolution of the hematopoietic stem cell microenvironment reveals a high degree of specialization and conservation

Understanding the regulation of normal and malignant human hematopoiesis requires comprehensive cell atlas of the hematopoietic stem cell (HSC) regulatory microenvironment. Here, we develop a tailored bioinformatic pipeline to integrate public and proprietary single-cell RNA sequencing (scRNA-seq) datasets. As a result, we robustly identify for the first time 14 intermediate cell states and 11 stages of differentiation in the endothelial and mesenchymal BM compartments, respectively. Our data provide the most comprehensive description to date of the murine HSC-regulatory microenvironment and suggest a higher level of specialization of the cellular circuits than previously anticipated. Furthermore, this deep characterization allows inferring conserved features in human, suggesting that the layers of microenvironmental regulation of hematopoiesis may also be shared between species. Our resource and methodology is a stepping-stone toward a comprehensive cell atlas of the BM microenvironment.

Regulatory role of insulin-like growth factor-binding proteins in odontogenic mineralization in rats

Much information is currently available for molecules in early odontogenesis, but there is limited knowledge regarding terminal cytodifferentiation of ameloblasts and odontoblasts for the determination of normal crown morphology. The present differential display PCR (DD-PCR) revealed that insulin-like growth factor-binding protein 5 (IGFBP5) was differentially expressed in molar tooth germs between the cap (before crown mineralization) and root formation (after crown mineralization) stages. Real-time PCR confirmed that the expression levels of IGFBP1-4 were not significantly changed but those of IGFBP5-7 were upregulated in a time-dependent manner. Immunoreactivities for IGFBP5-7 were hardly seen in molar germs at the cap/early bell stage and protective-stage ameloblasts at the root formation stage. However, the reactivity was strong in odontoblasts and maturation-stage ameloblasts, which are morphologically and functionally characterized by wide intercellular space and active enamel matrix mineralization. The localization of each IGFBP was temporospatial. IGFBP5 was localized in the nuclei of fully differentiated odontoblasts and ameloblasts, while IGFBP6 was localized in the apical cytoplasm of ameloblasts and odontoblasts with dentinal tubules, and IGFBP7 was mainly found in the whole cytoplasm of odontoblasts and the intercellular space of ameloblasts. IGFBP silencing using specific siRNAs upregulated representative genes for dentinogenesis and amelogenesis, such as DMP1 and amelogenin, respectively, and augmented the differentiation media-induced mineralization, which was confirmed by alizarin red s and alkaline phosphatase staining. These results suggest that IGFBP5-7 may play independent and redundant regulatory roles in late-stage odontogenesis by modulating the functional differentiation of ameloblasts and odontoblasts.

An Integrated Transcriptome Analysis Reveals IGFBP7 Upregulation in Vasculature in Traumatic Brain Injury

Vasculature plays critical roles in the pathogenesis and neurological repair of traumatic brain injury (TBI). However, how vascular endothelial cells respond to TBI at the molecular level has not been systematically reviewed. Here, by integrating three transcriptome datasets including whole cortex of mouse brain, FACS-sorted mouse brain endothelial cells, and single cell sequencing of mouse brain hippocampus, we revealed the key molecular alteration of endothelial cells characterized by increased Myc targets and Epithelial-Mesenchymal Transition signatures. In addition, immunofluorescence staining of patients’ samples confirmed that IGFBP7 was up-regulated in vasculature in response to TBI. TGFβ1, mainly derived from microglia and endothelial cells, sufficiently induces IGFBP7 expression in cultured endothelial cells, and is significantly upregulated in response to TBI. Our results identified IGFBP7 as a potential biomarker of vasculature in response to TBI, and indicate that TGFβ signaling may contribute to the upregulation of IGFBP7 in the vasculature.

Identification of a Prognostic Signature Based on the Expression of Genes Related to the Insulin Pathway in Early Breast Cancer

Introduction

Insulin and the insulin-like growth factor (IGF) family play a key role in breast cancer (BC).

Objective

In this study, we evaluated on a genomic scale the potential prognostic value of insulin signaling in early BC.

Methods

Candidate genes were selected from the published literature and gene expression profiling experiments. Three publicly available BC datasets, containing gene expression data on 502 cases, were used to test the prognostic ability of the score. The gene signature was developed on GSE1456, containing microarray data from 159 patients, split into a training set (102 breast tumors) and a validation set (n = 57). GSE3494 and GSE2990 (350 patients) were used for external validation. Univariate Mann-Whitney test was used to identify genes differentially expressed between relapsed and nonrelapsed patients. Expression of genes significantly correlated with relapse was combined in a linear score. Patients were classified as low or high risk with respect to the median value.

Results

On the training set, 15 genes turned out to be differentially expressed: 8-year disease-free survival (DFS) was 51 and 91% in the high- and low-risk group (p < 0.001), respectively. In the validation set, DFS was 97 and 54% (p = 0.009), respectively. External validation: 8-year DFS was 72 and 61%, respectively, in GSE3494 (p = 0.03) and 74 and 55% in GSE2990 (p = 0.03). By multivariate analyses, the insulin signature was significantly associated with DFS, independently of age, hormone receptor status, nodal status, and grade.

Conclusions

Our findings indicate that the insulin pathway is involved in BC prognosis at a genomic level and provide a window of selectivity for preventive and treatment strategies targeting the insulin/IGF pathway in BC patients.

The secretome from embryonic stem cell cardiomyogenesis: Same signals, different cellular feedbacks

Ischemic heart diseases are a global health problem that requires the search for alternative therapies to the current treatments. Thus, an understanding of how cardiomyogenic signals can affect cellular behavior would allow us to create strategies to improve the cell recovery in damaged tissues. In this study, we aimed to evaluate the effects of the conditioned medium (CM), collected at different time points during in vitro cardiomyogenesis of human embryonic stem cells (hESCs), to direct cell behavior. We assayed different cell types to demonstrate noncytotoxic effects from the collected CM and that the CM obtained at initial time points of cardiomyogenic differentiation could promote the cell proliferation. Otherwise, the secretome derived from cardiac committed cells during cardiomyogenesis was unable to improve angiogenesis or migration in endothelial cells, and ineffective to stimulate the differentiation of cardioblasts or increase the differentiation efficiency of hESC. Therefore, we demonstrated that the effectiveness of the CM response varies depending on the cell type and the differentiation step of hESC-derived cardiomyocytes.

Angiomodulin (IGFBP7) is a cerebral specific angiocrine factor, but is probably not a blood-brain barrier inducer

BACKGROUND

Several secreted factors have been identified as drivers of cerebral vasculature development and inducers of blood-brain barrier (BBB) differentiation. Vascular endothelial growth factor A (VEGF-A) is central for driving cerebral angiogenesis and Wnt family factors (Wnt7a, Wnt7b and norrin) are central for induction and maintenance of barrier properties. Expressed by developing neural tissue (neuron and glia progenitors), they influence the formation of central nervous system (CNS) vascular networks. Another type of factors are tissue-specific paracrine factors produced by endothelial cells (ECs), also known as 'angiocrine' factors, that provide instructive signals to regulate homeostatic and regenerative processes. Very little is known about CNS angiocrine factors and their role in BBB development. Angiomodulin (AGM) was reported to be expressed by developing vasculature and by pathological tumor vasculature. Here we investigated AGM in the developing CNS and its function as a potential BBB inducer.

METHODS

We analyzed microarray data to identify potential angiocrine factors specifically expressed at early stages of barrier formation. We then tested AGM expression with immunofluorescence and real-time PCR in various organs during development, post-natal and in adults. Permeability induction with recombinant proteins (Miles assay) was used to test potential interaction of AGM with VEGF-A.

RESULTS

Several angiocrine factors are differentially expressed by CNS ECs and AGM is a prominent CNS-specific angiocrine candidate. Contrary to previous reports, we found that AGM protein expression is specific to developing CNS endothelium and not to highly angiogenic developing vasculature in general. In skin vasculature we found that AGM antagonizes VEGF-A-induced vascular hyperpermeability. Finally, CNS AGM expression is not specific to BBB vasculature and AGM is highly expressed in non-BBB choroid-plexus vasculature.

CONCLUSIONS

We propose AGM as a developmental CNS vascular-specific marker. AGM is not a pan-endothelial marker, nor a general marker for developing angiogenic vasculature. Thus, AGM induction in the developing CNS might be distinct from its induction in pathology. While AGM is able to antagonize VEGF-A-induced vascular hyperpermeability in the skin, its high expression levels in non-BBB CNS vasculature does not support its potential role as a BBB inducer. Further investigation including loss-of-function approaches might elucidate AGM function in the developing CNS.

Insulin-like growth factor-binding protein 7 (IGFBP7): Novel, independent marker of cardiometabolic diseases?

Insulin-like growth factor-binding protein 7 (IGFBP7) is a 30kDa modular secreted protein involved in many physiologic processes, including cell proliferation, adhesion, senescence and angiogenesis. It is expressed in many organs and specific cells. It can interact with insulin-like growth factor 1(IGF-1), as well as with insulin. By binding to IGF-1, it limits IGF-1 access to IGF- receptor (IGF-R) and consequently neutralizes IGF-1 activity. Moreover, due to its high affinity to insulin, it may interfere with biological response of insulin and, therefore, it may be involved in the development of diabetes and cardiovascular diseases. According to research, it could be a good biomarker of heart failure. Its elevated serum concentrations were found in patients with heart failure, both with reduced ejection fraction and preserved ejection fraction. Moreover, IGFBP7 could be useful in predicting the presence of atherosclerotic lesions in coronary vessels, although its concentration does not reflect a degree of coronary artery disease (CAD) advancement and it cannot be used as a marker of acute ischemia. Its concentration is also associated with insulin resistance and the risk of metabolic syndrome. What is more, together with tissue inhibitor of metalloproteinases-2, it is a novel marker of tubular damage and it can be used for an early detection of acute kidney injury (AKI) endangered patients, which could allow for subsequent adjustments in medical therapy and the prevention of AKI. IGFBP7 is also regarded as a potential tumor suppressor in various cancers. Its low expression is potentially correlated with increased cancer cell proliferation.

Non-nutritional sweeteners effects on endothelial vascular function

AIM

Hyperglycemia status induces endothelial dysfunction, although the underlying pathogenic mechanisms are not fully understood. There are several studies connecting sugar/sweetened beverages to the cardiovascular disease. Currently, many sweeteners have been extensively introduced into lifestyle to normalize blood glucose levels without altering the sweet taste. However, there is growing concern for their impact on metabolic health.

METHODS

Human endothelial cells were treated with Glucose, Fructose, Aspartame, Rebaudioside A, Stevioside, or Steviol. Morphological characteristics, in vitro angiogenesis and array gene expression were analyzed.

RESULTS

High-glucose and fructose concentrations significantly decreased cell features such as angiogenic capability. Interestingly, non-caloric sweeteners did not significantly modified all cell characteristics and they did not compromised cell angiogenic ability. Array gene expression analysis revealed that the chemokine fractalkine (CX3CL1) and the enzyme transferase (HPRT1) were always significantly upregulated and downregulated respectively, after glucose and fructose treatments (P > .05), whereas they were non-differentially expressed with all the other sweeteners. Interestingly, both genes are considered as cardiovascular disease risk biomarkers. Specifically, upregulation of CX3CL1/CX3CR1 occurs in the human placenta and serum levels of the ligand are associated with markers of insulin resistance in GDM.

CONCLUSIONS

Differently from glucose and fructose, steviol glycosides do not damage endothelial cells. Prospective preclinical studies and clinical trials are warranted to confirm the long-term safety of such compounds.

Downregulated IGFBP7 facilitates liver metastasis by modulating epithelial‑mesenchymal transition in colon cancer

Distant metastasis is a major cause of cancer-associated mortality in patients with colon cancer. Insulin-like growth factor binding protein 7 (IGFBP7) has been identified as a crucial inhibitor of human cancer. However, the role of IGFBP7 in the pathogenesis of metastatic colon cancer has not been investigated. In the present study, the expression of IGFBP7 in 81 pairs of colon cancer tissues and adjacent normal tissues were investigated using immunohistochemistry. Furthermore, 24 pairs of primary colon cancer and matched liver metastasis tissues were analyzed. LοVο cells with IGFBP7-knockdown and HT-29 cells with IGFBP7-overexpression were employed. The expression levels of E-cadherin, N-cadherin and Vimentin were quantified and compared. Significant alterations in the expression of IGFBP7 between late stage (III + IV) colon cancer and adjacent normal colonic mucosa were observed. (P=0.031). The association between IGFBP7 and epithelial-mesenchymal transition (EMT) markers were validated in primary colon cancer and matched liver metastasis tissues. The invasive front of liver metastatic colon tissues revealed reduced IGFBP7 expression. Additionally, knockdown of IGFBP7 in LοVο cells resulted in decreased E-cadherin, and increased N-cadherin and Vimentin expression compared with the control group. Overexpression of IGFBP7 in HT-29 cells induced an upregulation of E-cadherin; however, the N-cadherin and Vimentin levels were decreased. In conclusion, the results of the present study suggested that IGFBP7 may prevent colon cancer metastasis by inhibiting EMT, and serves as a potential diagnostic marker and therapeutic target for patients with colon cancer.

Insulin-like growth factor binding protein-7: A marker of conjunctivalization in an animal model of limbal stem cell deficiency

PURPOSE

Limbal stem cell deficiency (LSCD) is characterized by the loss of limbal epithelial stem cells, resulting in a pathological process termed 'conjunctivalization' which compromises corneal transparency, leading to blindness. Current diagnosis for LSCD is limited because reliable conjunctiva-specific biomarkers are lacking. This study sought to address this shortcoming through the serendipitous discovery of insulin-like growth factor binding protein (IGFBP)-7.

METHODS

IGFBP-7 expression was determined in normal (n=83) and conjunctivalized (n=52) mouse corneas with experimentally-induced LSCD, and in cadaveric normal human corneas (n=7) and human pterygia (n=15); a disease characterized by the invasion of a conjunctivalized, fibrovascular pannus. Clinical assessments including slit-lamp microscopy, fluorescein staining and impression cytology, and biochemical, molecular and immunological assays were also conducted.

RESULTS

Mass spectrometry of conditioned media from mouse limbal explant-derived cells revealed the presence of IGFBP-7. This factor was expressed in normal limbal and conjunctival epithelium and conjunctivalized corneas from mice with LSCD, and in human pterygium epithelium but not in normal mouse or human corneal epithelium. Four weeks after inducing LSCD, IGFBP-7 staining was increased by 2.9-fold in mouse corneas compared to steady-state, and by 1.6-fold in impression cytology specimens derived from the same mice. Notably, IGFBP-7 was detected approximately 2-weeks earlier than Muc5AC.

CONCLUSIONS

This study provides novel insights into the specificity of IGFBP-7 for the mammalian conjunctival epithelium in health and disease. A point-of-care test for IGFBP-7 could be developed to assist clinicians in early diagnosis, and in monitoring disease progression, severity and therapeutic outcomes in patients with LSCD.

Insulin-like growth factor binding proteins and angiogenesis: from cancer to cardiovascular disease

Angiogenesis is a tightly regulated activity that is vital during embryonic development and for normal physiological repair processes and reproduction in healthy adults. Pathological angiogenesis is a driving force behind a variety of diseases including cancer and retinopathies, and inhibition of angiogenesis is a therapeutic option that has been the subject of much research, with several inhibitory agents now available for medical therapy. Conversely, therapeutic angiogenesis has been mooted as having significant potential in the treatment of ischemic conditions such as angina pectoris and peripheral arterial disease, but so far there has been less translation from lab to bedside. The insulin-like growth factor binding proteins (IGFBP) are a family of seven proteins essential for the binding and transport of the insulin-like growth factors (IGF). It is being increasingly recognised that IGFBPs have a significant role beyond simply modulating IGF activity, with evidence of both IGF dependent and independent actions through a variety of mechanisms. Moreover, the action of the IGFBPs can be stimulatory or inhibitory depending on the cell type and environment. Specifically the IGFBPs have been heavily implicated in angiogenesis, both pathological and physiological, and they have significant promise as targeted cell therapy agents for both pathological angiogenesis inhibition and therapeutic angiogenesis following ischemic injury. In this short review we will explore the current understanding of the individual impact of each IGFBP on angiogenesis, and the pathways through which these effects occur.

Insulin-like growth factor-binding protein 7 (IGFBP 7) as a new biomarker in coronary heart disease

PURPOSE

The role of insulin-like growth factor-binding protein-7 (IGFBP-7) in atherosclerosis is still not well-known. The objective of this study was to find out the following: 1) whether IGFBP-7 may act as a biomarker of coronary artery disease (CAD) occurrence and extent; 2) whether IGFBP-7 is potentially related to the classical and new markers of cardiovascular risk (carotid intima-media thickness - cIMT); 3) whether IGFBP-7 may be a marker of mortality in the group of patients with myocardial infarction (MI).

MATERIALS/METHODS

The study group consisted of 212 patients with MI and 75 patients with stable CAD, the control group included 100 healthy volunteers. IGFBP-7 serum concentration was measured.

RESULTS

IGFBP-7 value was considerably higher in the study group (MI and CAD patients - 35.1 ng/ml (P = 0.000001) and 32.7ng/ml (P = 0.0001), respectively), than in the controls - 25.2ng/ml. No statistically significant differences between IGFBP-7 concentrations in the MI and CAD group were found. No relationship between IGFBP-7 and the coronary lesions advancement in the study group was observed. No changes in IGFBP-7 concentration in the MI patients during hospitalization were observed. In the group of MI patients who died during follow-up, a considerably higher cIMT values were found whereas no statistically significant difference was observed in relation to IGFBP-7 (34.6 vs. 35.2 ng/ml).

CONCLUSIONS

IGFBP-7 is a good biomarker of CAD occurrence but not of its advancement. We demonstrated the existence of the relation between higher IGFBP-7 concentration and the selected classical risk factors of cardiovascular events as well as cIMT values. IGFBP-7 cannot serve as a marker of acute ischemia. Also, IGFBP-7 was not confirmed as a predictor of mortality in the MI patients.

Insulin-like growth factor binding protein related protein 1 knockdown attenuates hepatic fibrosis via the regulation of MMPs/TIMPs in mice

BACKGROUND

Previous research suggested that insulin-like growth factor binding protein related protein 1 (IGFBPrP1), as a novel mediator, contributes to hepatic fibrogenesis. Matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) play an essential role in hepatic fibrogenesis by regulating homeostasis and remodeling of the extracellular matrix (ECM). However, the interaction between IGFBPrP1 and MMP/TIMP is not clear. The present study was to knockdown IGFBPrP1 to investigate the correlation between IGFBPrP1 and MMP/TIMP in hepatic fibrosis.

METHODS

Hepatic fibrosis was induced by thioacetamide (TAA) in mice. Knockdown of IGFBPrP1 expression by ultrasound-targeted microbubble destruction-mediated CMB-shRNA-IGFBPrP1 delivery, or inhibition of the Hedgehog (Hh) pathway by cyclopamine treatment, was performed in TAA-induced liver fibrosis mice. Hepatic fibrosis was determined by hematoxylin and eosin and Sirius red staining. Hepatic expression of IGFBPrP1, α-smooth muscle actin (α-SMA), transforming growth factor β 1 (TGFβ1), collagen I, MMPs/TIMPs, Sonic Hedgehog (Shh), and glioblastoma family transcription factors (Gli1) were investigated by immunohistochemical staining and Western blotting analysis.

RESULTS

We found that hepatic expression of IGFBPrP1, TGFβ1, α-SMA, and collagen I were increased longitudinally in mice with TAA-induced hepatic fibrosis, concomitant with MMP2/TIMP2 and MMP9/TIMP1 imbalance and Hh pathway activation. Knockdown of IGFBPrP1 expression, or inhibition of the Hh pathway, reduced the hepatic expression of IGFBPrP1, TGFβ1, α-SMA, and collagen I and re-established MMP2/TIMP2 and MMP9/TIMP1 balance.

CONCLUSIONS

Our findings suggest that IGFBPrP1 knockdown attenuates liver fibrosis by re-establishing MMP2/TIMP2 and MMP9/TIMP1 balance, concomitant with the inhibition of hepatic stellate cell activation, down-regulation of TGFβ1 expression, and degradation of the ECM. Furthermore, the Hh pathway mediates IGFBPrP1 knockdown-induced attenuation of hepatic fibrosis through the regulation of MMPs/TIMPs balance.

Single-cell transcriptomic analysis of mouse neocortical development

The development of the mammalian cerebral cortex depends on careful orchestration of proliferation, maturation, and migration events, ultimately giving rise to a wide variety of neuronal and non-neuronal cell types. To better understand cellular and molecular processes that unfold during late corticogenesis, we perform single-cell RNA-seq on the mouse cerebral cortex at a progenitor driven phase (embryonic day 14.5) and at birth-after neurons from all six cortical layers are born. We identify numerous classes of neurons, progenitors, and glia, their proliferative, migratory, and activation states, and their relatedness within and across age. Using the cell-type-specific expression patterns of genes mutated in neurological and psychiatric diseases, we identify putative disease subtypes that associate with clinical phenotypes. Our study reveals the cellular template of a complex neurodevelopmental process, and provides a window into the cellular origins of brain diseases.

The determinants, biomarkers, and consequences of microvascular injury in kidney transplant recipients

Independent of the initial cause of kidney disease, microvascular injury to the peritubular capillary network appears to play a central role in the development of interstitial fibrosis in both native and transplanted kidney disease. This association is explained by mechanisms such as the upregulation of profibrotic genes and epigenetic changes induced by hypoxia, capillary leakage, endothelial and pericyte transition to interstitial fibroblasts, as well as modifications in the secretome of endothelial cells. Alloimmune injury due to antibody-mediated rejection and ischemia-reperfusion injury are the two main etiologies of microvascular damage in kidney transplant recipients. The presence of circulating donor-specific anti-human leukocyte antigen (HLA) antibodies, histological findings, such as diffuse C4d staining in peritubular capillaries, and the extent and severity of peritubular capillaritis, are commonly used clinically to provide both diagnostic and prognostic information. Complement-dependent assays, circulating non-HLA antibodies, or evaluation of the microvasculature with novel imaging techniques are the subject of ongoing studies.

A single-cell survey of the human first-trimester placenta and decidua

The placenta and decidua interact dynamically to enable embryonic and fetal development. Here, we report single-cell RNA sequencing of 14,341 and 6754 cells from first-trimester human placental villous and decidual tissues, respectively. Bioinformatic analysis identified major cell types, many known and some subtypes previously unknown in placental villi and decidual context. Further detailed analysis revealed proliferating subpopulations, enrichment of cell type-specific transcription factors, and putative intercellular communication in the fetomaternal microenvironment. This study provides a blueprint to further the understanding of the roles of these cells in the placenta and decidua for maintenance of early gestation as well as pathogenesis in pregnancy-related disorders.

Human adipose tissue-derived stem cells inhibit the activity of keloid fibroblasts and fibrosis in a keloid model by paracrine signaling

BACKGROUND

Human adipose tissue-derived mesenchymal stem cells (ASCs) have potential utility as modulators of the regeneration of tissue that is inflamed or scarred secondary to injuries such as burns or trauma. However, the effect of ASCs on one particular type of scarring, keloidal disease, remains unknown. The absence of an optimal model for investigation has hindered the development of an effective therapy using ASCs for keloids.

OBJECTIVE

To investigate the influence of ASCs on angiogenesis, extracellular matrix deposition, and inflammatory cell influx in keloids.

METHODS

We analyzed the proliferation, migration, and apoptosis of human keloid-derived fibroblasts treated with a starvation-induced, conditioned medium from ASCs (ASCs-CM). This was achieved by Brdu proliferation assay, a validated co-culture migration assay, and flow cytometry, respectively. To assess the change in phenotype to a pro-fibrotic state, fibroblasts were analyzed by real-time PCR and contraction assay. A keloid implantation animal model was used to assess the paracrine effect of ASCs histochemically and immunohistochemically on scar morphology, collagen deposition, inflammatory cell composition, and blood vessel density. In tandem, an antibody-based array was used to identify protein concentration in the presence of ASCs-CM at time point 0, 24, and 48h.

RESULTS

ASCs-CM inhibited the proliferation and collagen synthesis of human keloid-derived fibroblasts. ASCs-CM was associated with reduced inflammation and fibrosis in the keloid implantation model. Thirty-four cytokines were differentially regulated by ASCs-CM at 24h. These included molecules associated with apoptosis, matrix metalloproteases, and their inhibitors. The same molecules were present at relatively higher concentrations at the 48h timepoint.

CONCLUSION

These results suggest that ASCs are associated with the inhibition of fibrosis in keloids by a paracrine effect. This phenomenon may have utility as a therapeutic approach in the clinical environment.

Combined detection of insulin-like growth factor-binding protein 7 promoter methylation improves the diagnostic efficacy of AFP in hepatitis B virus-associated hepatocellular carcinoma

This study quantitatively assessed serum insulin-like growth factor-binding protein 7 (IGFBP7) promoter methylation in hepatocellular carcinoma (HCC), and explored its clinical value. A total of 80 patients with hepatitis B virus-associated HCC, 35 patients with chronic hepatitis B (CHB), and 20 healthy controls (HC) were enrolled. MethyLight was used to quantitatively assess the methylation levels of serum IGFBP7 promoter. A logistic regression model was established for the combined evaluation of AFP and serum IGFBP7 promoter methylation. The results showed that mean methylation levels of serum IGFBP7 promoter were significantly higher in HCC (5.33%, interquartile range [IQR] 1.14-15.70%) patients than in individuals with CHB (1.54%, IQR 0.64-2.45%; P<0.01) and HC (0.63%, IQR 0.22-0.98%; P<0.01). In HCC subgroups, patients with vascular invasion, tumor size >3cm and advanced tumor node metastasis (TNM) showed higher methylation levels compared with the remaining groups (P<0.05). Compared with AFP alone, combined determination based on logistic regression analysis significantly improved the area under the receiver operating characteristic (ROC) curve (AUC) (0.759 vs 0.623, P<0.05). In addition, the Youden index was increased from 5.71%, 11.25% and 15.18%, when considering AFP alone at cut-off values of 20, 200, and 400ng/ml, respectively, to 45.71% with IGFBP7 promoter methylation taken into consideration (all P<0.05). These results suggested that combined quantitative measurement of serum IGFBP7 promoter methylation could enhance the diagnostic ability of AFP in distinguishing hepatitis B virus-associated HCC from CHB.

Insulin-like growth factor axis targeting in cancer and tumour angiogenesis - the missing link

Numerous molecular players in the process of tumour angiogenesis have been shown to offer potential for therapeutic targeting. Initially denoted to be involved in malignant transformation and tumour progression, the insulin-like growth factor (IGF) signalling axis has been subject to therapeutic interference, albeit with limited clinical success. More recently, IGFs and their receptors have received attention for their contribution to tumour angiogenesis, which offers novel therapeutic opportunities. Here we review the contribution of this signalling axis to tumour angiogenesis, the mechanisms of resistance to therapy and the interplay with other pro-angiogenic pathways, to offer insight in the renewed interest in the application of IGF axis targeting agents in anti-cancer combination therapies.

Screening for and validation of a hepatic fibrosis-related pathway induced by insulin-like growth factor-binding protein-related protein 1

OBJECTIVE

Our previous studies characterized insulin-like growth factor-binding protein-related protein 1 (IGFBPrP1) as a molecule that promotes hepatic fibrogenesis, but its mechanism has not been fully elucidated. Here, we have investigated the effect of IGFBPrP1 on gene expression in the hepatic fibrosis-related pathway.

MATERIALS AND METHODS

Sprague-Dawley rats received injections of an adenovirus carrying IGFBPrP1 or EGFP cDNA into their tail veins. In hepatic preparations, hepatic stellate cell activation was determined by α-smooth muscle actin expression and hepatic fibrosis by Sirius red staining and hydroxyproline content analysis. IGFBPrP1-inducible genes of the hepatic fibrosis-related pathway were assessed by PCR array. Expression of IGFBPrP1 and transforming growth factor β1 (TGFβ1) and array results were evaluated by quantitative real-time PCR and western blotting.

RESULTS

IGFBPrP1-overexpressing rats showed an increase in α-smooth muscle actin expression and collagen and hydroxyproline content in the liver. The PCR array results indicated that some genes were upregulated and some were downregulated in Ad-IGFBPrP1-infected rats. Among these, Egr1, MAP2K2 (MEK2) and MAPK3 (ERK1) expression increased, whereas PTEN and Hhip mRNA expression decreased. Egr1 protein levels increased and peaked 2 weeks after infection and then decreased gradually. PTEN protein decreased gradually in Ad-IGFBPrP1-infected rats with a concurrent increase in the degree of hepatic fibrosis. TGFβ1 levels increased during hepatic fibrosis development in liver tissues.

CONCLUSION

Egr1, PTEN, Hhip, MAP2K2 (MEK2) and MAPK3 (ERK1) were identified as candidate genes of the IGFBPrP1-induced hepatic fibrosis-related pathway. IGFBPrP1 promoted hepatic fibrosis mainly by enhancing the TGFβ1 expression that it triggered.

Biomarkers in Acute Kidney Injury

Acute kidney injury (AKI) is a common and often lethal complication that is also associated with severe morbidity in hospitalized patients. During the last decade, the standardization of AKI diagnostic criteria has helped to facilitate several large-scale investigations of biomarkers of AKI. These studies have led to the international clinical implementation of several biomarkers of renal injury. This review summarizes the results of many of these multicenter investigations and discusses the clinical utility and interpretation of several of these new clinical tests. The merits of combining biomarkers of kidney function is also discussed.

Insulin like growth factor binding protein 7 (IGFBP7) expression is linked to poor prognosis but may protect from bone disease in multiple myeloma

Background

Insulin like growth factor binding protein 7 (IGFBP7) is a secreted protein binding insulin like growth factor 1 (IGF-1), insulin, vascular endothelial growth factor A (VEGFA), and activin A. It antagonizes bone morphogenetic proteins and is involved in the tumour propagation of solid as well as haematological malignancies. Its role in multiple myeloma (MM) is not defined so far. We therefore aim here to investigate its prognostic and pathophysiological role in MM.

Methods

The clinical significance of IGFBP7 gene expression was investigated by gene expression profiling in two independent cohorts (n = 948) of newly-diagnosed MM patients. Methylation of the IGFBP7 promoter was analysed by pyrosequencing and treatment of MM cell lines with 5-aza-2-deoxycytidine. The impact of IGFBP7 on MM cells was studied by CCK-8 assay, BrdU assay and flow cytometry, respectively. IGFBP7 expression in bone marrow stromal cells (BMSCs) was studied by quantitative RT-PCR. For osteoblast development, immortalized and primary human BMSCs were cultured in osteogenic differentiation medium for 7–14 days in the presence of recombinant human IGFBP7 and/or activin A.

Results

Median IGFBP7 expression is significantly lower in CD138-purified plasma cells from individuals with MGUS and MM, compared to normal bone marrow plasma cells. IGFBP7 gene expression in MM cells is regulated by methylation, shown by pyrosequencing and exposure to demethylating agents (5-aza-2-deoxycytidine). High expression of IGFBP7 in MM cells is associated with adverse survival in two independent cohorts of 247 and 701 newly-diagnosed MM patients treated with high-dose therapy and autologous stem cell transplantation. IGFBP7 is associated with prognostically adverse chromosomal aberrations (t(4;14) and gain of 1q21), MMSET expression, and higher myeloma cell proliferation. In vitro, IGFBP7 overcomes activin A induced osteoblast suppression and promotes osteogenesis. MM cells downregulate IGFBP7 in stromal cells, possibly contributing to the osteoblast suppression found in MM. Conversely, higher IGFBP7 expression is associated with a lower probability of myeloma bone disease.

Conclusions

Our data indicate that IGFBP7 expression is a marker for a specific methylation pattern in myeloma, linked to translocation t(4;14) associated MMSET expression, showing clinical features of adverse prognosis with absence of myeloma bone disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-014-0105-1) contains supplementary material, which is available to authorized users.

Inhibitory effect of insulin-like growth factor-binding protein-7 (IGFBP7) on in vitro angiogenesis of vascular endothelial cells in the rat corpus luteum

Angiogenesis in the developing corpus luteum (CL) is a prerequisite for establishment and maintenance of an early pregnancy. To explore the physiological significance of insulin-like growth factor-binding protein-7 (IGFBP7) in the developing CL, the effects of IGFBP7 on vascular endothelial growth factor (VEGFA)- and luteinizing hormone (LH)-induced in vitro tube formation were tested using isolated luteal microvascular endothelial cells (LECs). Capillary-like tube formation of LECs and their proliferation were stimulated by both VEGFA and LH. IGFBP7 treatment suppressed VEGFA- or LH-induced tube formation. The proliferation and migration of LECs, and phosphorylation of mitogen-activated protein kinase kinase and extracellular signal-regulated kinase 1/2 were inhibited by IGFBP7. Furthermore, IGFBP7 attenuated VEGFA-enhanced cyclooxygenase (COX)-2 mRNA expression and prostaglandin E₂ secretion. These findings suggest the possibility that luteal IGFBP7 secretion may suppress the stimulatory effect of VEGFA on angiogenesis in the early CL.

Low expression of insulin-like growth factor binding protein 7 associated with poor prognosis in human glioma

OBJECTIVES

To investigate insulin-like growth factor binding protein 7 (IGFBP7) mRNA levels in human glioma and normal brain tissue, and to determine their clinical significance.

METHODS

In this retrospective study, IGFBP7 mRNA was quantified by real-time reverse transcription-polymerase chain reaction in brain tissue samples from patients with glioma and normal control subjects. Kaplan-Meier and Cox proportional hazards analyses were performed to determine any clinical and prognostic associations.

RESULTS

IGFBP7 mRNA levels were significantly lower in glioma tissue (n = 120) than in normal brain tissue (n = 20). Low (i.e. below the median, 5.9) IGFBP7 mRNA levels were significantly associated with larger tumour size (≥ 5 cm, compared with <5 cm, diameter). Patients with high (above median) IGFBP7 had longer overall survival than those with low IGFBP7. Tumour grade and IGFBP7 mRNA level were independent predictors of overall survival.

CONCLUSIONS

IGFBP7 downregulation is associated with poor prognosis in glioma, and this molecule may represent both a prognostic marker and a potential therapeutic target.

Platelet-derived growth factor regulates the secretion of extracellular vesicles by adipose mesenchymal stem cells and enhances their angiogenic potential

BACKGROUND

Several studies demonstrate the role of adipose mesenchymal stem cells (ASCs) in angiogenesis. The angiogenic mechanism has been ascribed to paracrine factors since these cells secrete a plenty of signal molecules and growth factors. Recently it has been suggested that besides soluble factors, extracellular vesicles (EVs) that include exosomes and microvesicles may play a major role in cell-to-cell communication. It has been shown that EVs are implicated in the angiogenic process.

RESULTS

Herein we studied whether EVs released by ASCs may mediate the angiogenic activity of these cells. Our results demonstrated that ASC-derived EVs induced in vitro vessel-like structure formation by human microvascular endothelial cells (HMEC). EV-stimulated HMEC when injected subcutaneously within Matrigel in SCID mice formed vessels. Treatment of ASCs with platelet-derived growth factor (PDGF) stimulated the secretion of EVs, changed their protein composition and enhanced the angiogenic potential. At variance of EVs released in basal conditions, PDGF-EVs carried c-kit and SCF that played a role in angiogenesis as specific blocking antibodies inhibited in vitro vessel-like structure formation. The enhanced content of matrix metalloproteinases in PDGF-EVs may also account for their angiogenic activity.

CONCLUSIONS

Our findings indicate that EVs released by ASCs may contribute to the ASC-induced angiogenesis and suggest that PDGF may trigger the release of EVs with an enhanced angiogenic potential.

Insulin-like growth factor binding protein-related protein 1 contributes to hepatic fibrogenesis

OBJECTIVE

The aim of this study was to investigate the role of insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1) in the development of hepatic fibrogenesis in experimental disease models and human liver samples.

METHODS

Cellular distribution patterns of IGFBP-rP1 were assessed by immunohistochemistry in fibrotic and cirrhotic human liver specimens. Gene silencing of IGFBP-rP1 was performed on cultured hepatic stellate cells (HSCs) by small interfering RNA (siRNA), and the silencing effect was determined by quantitative real-time polymerase chain reaction (PCR) and Western blot. We also determined the effects of siRNA-mediated gene silencing of IGFBP-rP1 on the production of extracellular matrix (ECM) components by Western blot. The expression of ECM components and transforming growth factor (TGF)-β1 was studied by immunohistochemistry and Western blot in C57BL/6 wild-type mice treated with recombinant IGFBP-rP1 (rIGFBP-rP1).

RESULTS

Expression of IGFBP-rP1 was significantly elevated in fibrotic and cirrhotic human liver specimens, and this increase was positively correlated with the number of collagen fibers observed. siRNA-mediated gene silencing of IGFBP-rP1 resulted in significantly decreased levels of collagen I and fibronectin in HSCs. Moreover, IGFBP-rP1 overexpression significantly increased the production of collagen, fibronectin and TGF-β1 in rIGFBP-rP1-treated mice.

CONCLUSIONS

IGFBP-rP1 contributes to the development of liver fibrosis and may be a novel molecule involved in the progression of hepatic fibrogenesis.

Emerging role of insulin-like growth factor-binding protein 7 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a vicious and highly vascular cancer with a dismal prognosis. It is a life-threatening illness worldwide that ranks fifth in terms of cancer prevalence and third in cancer deaths. Most patients are diagnosed at an advanced stage by which time conventional therapies are no longer effective. Targeted molecular therapies, such as the multikinase inhibitor sorafenib, provide a modest increase in survival for advanced HCC patients and display significant toxicity. Thus, there is an immense need to identify novel regulators of HCC that might be targeted effectively. The insulin-like growth factor (IGF) axis is commonly abnormal in HCC. Upon activation, the IGF axis controls metabolism, tissue homeostasis, and survival. Insulin-like growth factor-binding protein 7 (IGFBP7) is a secreted protein of a family of low-affinity IGF-binding proteins termed “IGFBP-related proteins” that have been identified as a potential tumor suppressor in HCC. IGFBP7 has been implicated in regulating cellular proliferation, senescence, and angiogenesis. In this review, we provide a comprehensive discussion of the role of IGFBP7 in HCC and the potential use of IGFBP7 as a novel biomarker for drug resistance and as an effective therapeutic strategy.

Insulin-like growth factor binding protein-related protein 1 and cancer

Insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1) belongs to the IGFBP family whose members have a conserved structural homology. It has a low affinity for IGFs and a high affinity for insulin, suggesting that IGFBP-rP1 may have a biological function distinct from other members of the family. IGFBP-rP1 is ubiquitously expressed in normal human tissues and has diverse biological functions, regulating cell proliferation, apoptosis and senescence; it may also have a key role in vascular biology. Increasing evidence suggests that IGFBP-rP1 acts as a tumor suppressor. It elicits its biological effects by both insulin/IGF-dependent and -independent mechanisms. This paper provides a brief overview of the structure and regulation of IGFBP-rP1 and its various biological functions in cancer, as well as the underlying molecular mechanisms.

Generating new neurons to circumvent your fears: the role of IGF signaling

Extinction of fear memory is a particular form of cognitive function that is of special interest because of its involvement in the treatment of anxiety and mood disorders. Based on recent literature and our previous findings (EMBO J 30(19):4071-4083, 2011), we propose a new hypothesis that implies a tight relationship among IGF signaling, adult hippocampal neurogenesis and fear extinction. Our proposed model suggests that fear extinction-induced IGF2/IGFBP7 signaling promotes the survival of neurons at 2-4 weeks old that would participate in the discrimination between the original fear memory trace and the new safety memory generated during fear extinction. This is also called "pattern separation", or the ability to distinguish similar but different cues (e.g., context). To understand the molecular mechanisms underlying fear extinction is therefore of great clinical importance.

Von Willebrand factor, angiodysplasia and angiogenesis

The large multimeric glycoprotein Von Willebrand factor (VWF) is best known for its role in haemostasis; however in recent years other functions of VWF have been identified, indicating that this protein is involved in multiple vascular processes. We recently described a new role for VWF in controlling angiogenesis, which may have significant clinical implications for patients with Von Willebrand disease (VWD), a genetic or acquired condition caused by the deficiency or dysfunction of VWF. VWD can be associated with angiodysplasia, a condition of degenerative blood vessels often present in the gastrointestinal tract, linked to dysregulated angiogenesis. Angiodysplasia can cause severe intractable bleeding, often refractory to conventional VWD treatments. In this review we summarise the evidence showing that VWF controls angiogenesis, and review the angiogenic pathways which have been implicated in this process. We discuss the possible mechanisms though which VWF regulates angiopoietin-2 (Ang-2) and integrin αvβ3, leading to signalling through vascular endothelial growth factor receptor-2 (VEGFR2), one of the most potent activators of angiogenesis. We also review the evidence that links VWF with angiodysplasia, and how the newly identified function of VWF in controlling angiogenesis may pave the way for the development of novel therapies for the treatment of angiodysplasia in congenital VWD and in acquired conditions such as Heyde syndrome.

Loss of IGFBP7 expression and persistent AKT activation contribute to SMARCB1/Snf5-mediated tumorigenesis

SMARCB1 (Snf5/Ini1/Baf47) is a potent tumor suppressor, the loss of which serves as the diagnostic feature in malignant rhabdoid tumors (MRT) and atypical teratoid/rhabdoid tumors (AT/RT), two highly aggressive forms of pediatric neoplasms. SMARCB1 is a core subunit of Swi/Snf chromatin remodeling complexes, and loss of SMARCB1 or other subunits of these complexes has been observed in a variety of tumor types. Here, we restore Smarcb1 expression in cells derived from Smarcb1-deficient tumors, which developed in Smarcb1 heterozygous p53(-/-) mice. We find that while re-introduction of Smarcb1 does not induce growth arrest, it restores sensitivity to programmed cell death and completely abolishes the ability of the tumor cells to grow as xenografts. We describe persistent activation of AKT signaling in Smarcb1-deficient cells, which stems from PI3K (phosphatidylinositol 3'-kinase)-mediated signaling and which contributes to the survival and proliferation of the tumor cells. We further demonstrate that inhibition of AKT is effective in preventing proliferation of Smarcb1-deficient cells in vitro and inhibits the development of xenografted tumors in vivo. Profiling Smarcb1-dependent gene expression, we find genes that require Smarcb1 and Swi/Snf for their expression to be enriched for extracellular matrix and cell adhesion functions. We find that Smarcb1 is required for transcriptional activation of Igfbp7, a member of the insulin-like growth factor-binding proteins family and a tumor suppressor in itself, and show that re-introduction of Igfbp7 alone can hinder tumor development. Our results define a novel mechanism for Smarcb1-mediated tumorigenesis and highlight potential therapeutic targets.

A novel role of IGFBP7 in mouse uterus: regulating uterine receptivity through Th1/Th2 lymphocyte balance and decidualization

Previously we have screened out Insulin-like Growth Factor Binding Protein 7 (IGFBP7) as a differentially expressed gene in post-implantation uterus versus pre-implantation uterus by suppressive subtractive hybridation. However its function in uterus was not clearly identified. In this research, the expression and function of IGFBP7 during post-implantation were studied. We found that IGFBP7 was mainly located in the glandular epithelium and the stroma, and was upregulated after embryo implantation. The vector pCR3.1-IGFBP7-t expressing partial IGFBP7 was constructed. Inhibition of IGFBP7 by specific DNA immunization induced significant reduction of implanted embryos and pregnancy rate. The number of implanted embryos (5.68±0.46) was significantly reduced after immunization with pCR3.1-IGFBP7-t, as compared with that of the mice immunized with the control vector (12.29±0.36) or saline (14.58±0.40) (p<0.01). After specific inhibition of IGFBP7, the T helper type 1 (Th1) cytokine IFNγ, was significantly elevated (p<0.05) and the Th2 cytokines IL-4 and IL-10, were reduced in uteri (p<0.05). The increase of Tbet and the decrease of Gata3 were found in mice peripheral lymphocytes by flow cytometry. The expression of decidualization marker IGFBP1 and angiogenesis regulator VEGF were declined in uteri (p<0.05). The expression of apoptosis-associated proteins, caspase3 and Bcl-2, were also declined (p<0.05). These results showed that inhibition of IGFBP7 induced pregnancy failure by shifting uterine cytokines to Th1 type dominance and repressing uterine decidualization.

Urinary proteomic shotgun approach for identification of potential acute rejection biomarkers in renal transplant recipients

BACKGROUND

Acute rejection (AR) episodes in renal transplant recipients are suspected when plasma creatinine is elevated and other potential causes out ruled. Graft biopsies are however needed for definite diagnosis. Non-invasive AR-biomarkers is an unmet clinical need. The urinary proteome is an interesting source in the search for such a biomarker in this population.

METHODS

In this proof of principle study, serial urine samples in the early post transplant phase from 6 patients with biopsy verified acute rejections and 6 age-matched controls without clinical signs of rejection were analyzed by shotgun proteomics.

RESULTS

Eleven proteins fulfilled predefined criteria for regulation in association with AR. They presented detectable regulation already several days before clinical suspicion of AR (increased plasma creatinine). The regulated proteins could be grouped by their biological function; proteins related to growth and proteins related to immune response. Growth-related proteins (IGFBP7, Vasorin, EGF and Galectin-3-binding protein) were significantly up-regulated in association with AR (P = 0.03) while proteins related to immune response (MASP2, C3, CD59, Ceruloplasmin, PiGR and CD74) tended to be up-regulated ( P = 0.13).

CONCLUSION

The use of shotgun proteomics provides a robust and sensitive method for identification of potentially predictive urinary biomarkers of AR. Further validation of the current findings is needed to establish their potential clinical role with regards to clinical AR diagnosis.

TRIAL REGISTRATION

ClinicalTrials.gov number NCT00139009.

IGFBP7's susceptibility to proteolysis is altered by A-to-I RNA editing of its transcript

The selective deamination of adenosines (A) to inosines (I) in messenger RNAs (mRNAs) can alter the encoded protein's amino acid sequence, with often critical consequences on protein stability, localization, and/or function. Insulin-like growth factor-binding protein 7 (IGFBP7) supports cell-adhesion and stimulates fibroblast proliferation with IGF and insulin. It exists in both proteolytically processed and unprocessed forms with altered cell-extracellular matrix interactions. Here we show that editing of IGFBP7 transcripts impacts the protein's susceptibility to proteolytic cleavage, thus providing a means for a cell to modulate its functionality through A-to-I RNA editing.

Proteomic screen identifies IGFBP7 as a novel component of endothelial cell-specific Weibel-Palade bodies

Vascular endothelial cells contain unique storage organelles, designated Weibel-Palade bodies (WPBs), that deliver inflammatory and hemostatic mediators to the vascular lumen in response to agonists like thrombin and vasopressin. The main component of WPBs is von Willebrand factor (VWF), a multimeric glycoprotein crucial for platelet plug formation. In addition to VWF, several other components are known to be stored in WPBs, like osteoprotegerin, monocyte chemoattractant protein-1 and angiopoetin-2 (Ang-2). Here, we used an unbiased proteomics approach to identify additional residents of WPBs. Mass spectrometry analysis of purified WPBs revealed the presence of several known components such as VWF, Ang-2, and P-selectin. Thirty-five novel candidate WPB residents were identified that included insulin-like growth factor binding protein-7 (IGFBP7), which has been proposed to regulate angiogenesis. Immunocytochemistry revealed that IGFBP7 is a bona fide WPB component. Cotransfection studies showed that IGFBP7 trafficked to pseudo-WPB in HEK293 cells. Using a series of deletion variants of VWF, we showed that targeting of IGFBP7 to pseudo-WPBs was dependent on the carboxy-terminal D4-C1-C2-C3-CK domains of VWF. IGFBP7 remained attached to ultralarge VWF strings released upon exocytosis of WPBs under flow. The presence of IGFBP7 in WPBs highlights the role of this subcellular compartment in regulation of angiogenesis.