Legumain-deficient macrophages regulate inflammation and lipid metabolism in adipose tissues to protect against diet-induced obesity

Adipose tissue macrophages (ATMs) are key players in the development of obesity and associated metabolic inflammation, which contributes to systemic metabolic dysfunction, and understanding the interaction between macrophages and adipocytes is crucial for developing novel macrophage-based strategies against obesity. Here, we found that Legumain (Lgmn), a well-known lysosomal cysteine protease, is expressed mainly in the ATMs of obese mice. To further define the potential role of Lgmn-expressing macrophages in the generation of an aberrant metabolic state, LgmnF/F; LysMCre mice, which do not express Lgmn in macrophages, were maintained on a high-fat diet (HFD), and metabolic parameters were assessed. Macrophage-specific Lgmn deficiency protects mice against HFD-induced obesity, diminishes the quantity of proinflammatory macrophages in obese adipose tissues, and alleviates hepatic steatosis and insulin resistance. By analysing the transcriptome and proteome of murine visceral white adipose tissue (vWAT) after HFD feeding, we determined that macrophage Lgmn deficiency causes changes in lipid metabolism and the inflammatory response. Furthermore, the reciprocity of macrophage-derived Lgmn with integrin α5β1 in adipocytes was tested via colocalization analyses. It is further demonstrated in macrophage and adipocyte coculture system that macrophage derived Lgmn bound to integrin α5β1 in adipocytes, therefore attenuating PKA activation, downregulating lipolysis-related proteins and eventually exacerbating obesity development. Overall, our study identified Lgmn as a previously unrecognized regulator involved in the interaction between ATMs and adipocytes contributing to diet-induced obesity and suggested that Lgmn is a potential target for treating metabolic disorders.

Rejuvenating Hyaline Cartilaginous Phenotype of Dedifferentiated Chondrocytes in Collagen II Scaffolds: A Mechanism Study Using Chondrocyte Membrane Nanoaggregates as Antagonists

Joint cartilage lesions affect the global population in the current aging society. Maintenance and rejuvenation of articular cartilage with hyaline phenotype remains a challenge as the underlying mechanism has not been completely understood. Here, we have designed and performed a mechanism study using scaffolds made of type II collagen (Col2) as the 3D cell cultural platforms, on some of which nanoaggregates comprising extracts of chondrocyte membrane (CCM) were coated as the antagonist of Col2. Dedifferentiated chondrocytes were, respectively, seeded into these Col2 based scaffolds with (antCol2S) or without (Col2S) CCM coating. After 6 weeks, in Col2S, the chondrocytes were rejuvenated to regain hyaline phenotype, whereas this redifferentiation effect was attenuated in antCol2S. Transcriptomic and proteomic profiling indicated that the Wnt/β-catenin signaling pathway, which is an opponent to maintenance of the hyaline cartilaginous phenotype, was inhibited in Col2S, but it was contrarily upregulated in antCol2S due to the antagonism and shielding against Col2 by the CCM coating. Specifically, in antCol2S, since the coated CCM nanoaggregates contain the same components as those present on the surface of the seeded chondrocytes, the corresponding ligand sites on Col2 had been preoccupied and saturated by CCM coating before exposure to the seeded cells. The results indicated that the ligation between Col2 ligands and integrin α5 receptors on the surface of the seeded chondrocytes in antCol2S was antagonized by the CCM coating, which facilitates the Wnt/β-catenin signaling toward the loss of hyaline cartilaginous phenotype. This finding reveals the contribution of Col2 for maintenance and rejuvenation of the hyaline cartilaginous phenotype in chondrocytes.

PDE4 Phosphodiesterases in Cardiovascular Diseases: Key Pathophysiological Players and Potential Therapeutic Targets

3',5'-cyclic adenosine monophosphate (cAMP) is a second messenger critically involved in the control of a myriad of processes with significant implications for vascular and cardiac cell function. The temporal and spatial compartmentalization of cAMP is governed by the activity of phosphodiesterases (PDEs), a superfamily of enzymes responsible for the hydrolysis of cyclic nucleotides. Through the fine-tuning of cAMP signaling, PDE4 enzymes could play an important role in cardiac hypertrophy and arrhythmogenesis, while it decisively influences vascular homeostasis through the control of vascular smooth muscle cell proliferation, migration, differentiation and contraction, as well as regulating endothelial permeability, angiogenesis, monocyte/macrophage activation and cardiomyocyte function. This review summarizes the current knowledge and recent advances in understanding the contribution of the PDE4 subfamily to cardiovascular function and underscores the intricate challenges associated with targeting PDE4 enzymes as a therapeutic strategy for the management of cardiovascular diseases.

Rhinovirus infection of bronchial epithelium induces specific bronchial smooth muscle cell migration of severe asthmatic patients

BACKGROUND

Patients with severe asthma show an increase in both exacerbation frequency and bronchial smooth muscle (BSM) mass. Rhinovirus (RV) infection of the bronchial epithelium (BE) is the main trigger of asthma exacerbations. Histological analysis of biopsies shows that a close connection between BE and hypertrophic BSM is a criterion for severity of asthma.

OBJECTIVE

We hypothesized that RV infection of BE specifically increases asthmatic BSM cell migration.

METHODS

Serum samples, biopsies or BSM cells were obtained from 86 patients with severe asthma and 31 non-asthmatic subjects. BE cells from non-asthmatic subjects were cultured in an air-liquid interface and exposed to RV-16. Migration of BSM cells was assessed in response to BE supernatant using chemotaxis assays. Chemokine concentrations were analyzed by transcriptomics and ELISAs. Immunocytochemistry, western blotting and flow cytometry were used to quantify CXCR3 isoform distribution. CXCR3 downstream signaling pathways were assessed by calcium imaging and western blots.

RESULTS

BSM cells from severe asthmatic patients specifically migrated toward RV-infected BE, whereas those from non-asthmatic subjects did not. This specific migration is driven by BE CXCL10, which was increased in vitro in response to RV infection as well as in vivo in serum from exacerbating patients with severe asthma. The mechanism is related to both decreased expression and activation of the CXCR3-B-specific isoform in severe asthmatic BSM cells.

CONCLUSION

We have demonstrated a novel mechanism of BSM remodeling in severe asthmatic patients following RV exacerbation. This study highlights the CXCL10/CXCR3-A axis as a potential therapeutic target in severe asthma.

Apoptotic and anti-angiogenic effects of propolis against human bladder cancer: molecular docking and in vitro screening

INTRODUCTION

Bladder cancer is still of unknown initiation and progression, it is difficult to treat the patient once bladder cancer have a distant metastasis.

MATERIALS AND METHODS

In the present study, propolis extract was evaluated against bladder cancer cells (T24). Two independent pathways were investigated, apoptosis and angiogenesis, Bax, Bcl-2, P53, and caspase-3 for apoptosis, vascular endothelial growth factor receptor and protein kinase A as angiogenesis potential targets.

OBJECTIVES

Molecular docking studies will be conducted for the major known constituents of Egyptian propolis into apoptotic and angiogenic protein targets, to give better insights to the possible binding mode and interactions and investigate the ability of propolis constituents to target both apoptotic and angiogenic pathways.

RESULTS

Propolis showed anti-proliferative activity against T24 cancer cell line, the IC₅₀ value was 6.36 µg/ml. Also significant effects of propolis on Bax, Bcl-2, P53, and caspase-3 were observed.

DISCUSSION

These obtained results proved the ability of propolis to induce cell death. Also it has revealed noticeable effects on protein kinase A and vascular endothelial growth factor receptor.

CONCLUSION

The obtained results can encourage us to say that propolis extract can induce a programmed cell death in human bladder cancer cells, and also affect angiogenesis.

Contribution of CXCR3-mediated signaling in the metastatic cascade of solid malignancies

Metastasis is a significant cause of the mortality resulting from solid malignancies. The process of metastasis is complex and is regulated by numerous cancer cell-intrinsic and -extrinsic factors. CXCR3 is a chemokine receptor that is frequently expressed by cancer cells, endothelial cells and immune cells. CXCR3A signaling in cancer cells tends to promote the invasive and migratory phenotype of cancer cells. Indirectly, CXCR3 modulates the anti-tumor immune response resulting in variable effects that can permit or inhibit metastatic progression. Finally, the activity of CXCR3B in endothelial cells is generally angiostatic, which limits the access of cancer cells to key conduits to secondary sites. However, the interaction of these activities within a tumor and the presence of opposing CXCR3 splice variants clouds the picture of the role of CXCR3 in metastasis. Consequently, thorough analysis of the contributions of CXCR3 to cancer metastasis is necessary. This review is an in-depth examination of the involvement of CXCR3 in the metastatic process of solid malignancies.

Restraint stress induces uterine microenvironment disorder in mice during early pregnancy through the β2-AR/cAMP/PKA pathway

During pregnancy, uterus undergoes the environment adaptation as part of a program of development. In the world, one in four people worldwide suffer from mental illness, especially pregnant women. β-Adrenergic receptor (β-AR) is an important regulator that converts environmental stimuli into intracellular signals in mice uterus. CD-1 (ICR) mice undergone restraint stress, which was a case in model to simulate the psychological stress. The plasma and implantation sites in uterus were obtained and examined. PCR analysis demonstrated that β₂-AR expression levels in embryo day (E) 3, 5 and 7 were kept at a significantly higher level (p < 0.05) under restraint stress and higher than β₁-AR and β₃-AR in different gestation ages. The β₂-AR protein levels were obviously increased (p < 0.05) due to the markedly elevated norepinephrine (NE) concentration (p < 0.05). In our previous study, restraint stress can induce the apoptosis and inflammation. Also, the matrix metalloprotein-9 (MMP-9) was decreased significantly (p < 0.05) under restraint stress. Meanwhile, Caspase3, p-NF-κB p65 and p-ERK1/2 were obviously increased (p < 0.05) in the work. In vitro studies showed that the p-ERK1/2 and Caspase-3 levels were raised (p < 0.05) after β₂-AR was activated. However, they were decreased when PKA was blocked. The protein levels of Caspase-3 were reduced when ERK and NF-κB were blocked (p < 0.05). In conclusion, the β₂-AR/cAMP/PKA pathway promoted apoptosis and affected the development of the uterus through the ERK and NF-κB signaling pathway. The findings of this study may provide evidence for female reproduction under psychological stress.

Caffeine Inhibits Direct and Indirect Angiogenesis in Zebrafish Embryos

In this study, we report the effects of caffeine on angiogenesis in zebrafish embryos both during normal development and after exposure to Fibroblast Growth Factor 2 (FGF2). As markers of angiogenesis, we measured the length and width of intersegmental vessels (ISVs), performed whole-mount in situ hybridization with fli1 and cadh5 vascular markers, and counted the number of interconnecting vessels (ICVs) in sub-intestinal venous plexus (SIVP). In addition, we measured angiogenesis after performing zebrafish yolk membrane (ZFYM) assay with microinjection of fibroblast growth factor 2 (FGF2) and perivitelline tumor xenograft assay with microinjection of tumorigenic FGF2-overexpressing endothelial (FGF2-T-MAE) cells. The results showed that caffeine treatment causes a shortening and thinning of ISVs along with a decreased expression of the vascular marker genes and a decrease in the number of ICVs in the SIVP. Caffeine was also able to block angiogenesis induced by exogenous FGF2 or FGF2-producing cells. Overall, our results are suggestive of the inhibitory effect of caffeine in both direct and indirect angiogenesis.

Targeting RGD-binding integrins as an integrative therapy for diabetic retinopathy and neovascular age-related macular degeneration

Integrins are a class of transmembrane receptors that are involved in a wide range of biological functions. Dysregulation of integrins has been implicated in many pathological processes and consequently, they are attractive therapeutic targets. In the ophthalmology arena, there is extensive evidence suggesting that integrins play an important role in diabetic retinopathy (DR), age-related macular degeneration (AMD), glaucoma, dry eye disease and retinal vein occlusion. For example, there is extensive evidence that arginyl-glycyl-aspartic acid (Arg-Gly-Asp; RGD)-binding integrins are involved in key disease hallmarks of DR and neovascular AMD (nvAMD), specifically inflammation, vascular leakage, angiogenesis and fibrosis. Based on such evidence, drugs that engage integrin-linked pathways have received attention for their potential to block all these vision-threatening pathways. This review focuses on the pathophysiological role that RGD-binding integrins can have in complex multifactorial retinal disorders like DR, diabetic macular edema (DME) and nvAMD, which are leading causes of blindness in developed countries. Special emphasis will be given on how RGD-binding integrins can modulate the intricate molecular pathways and regulate the underlying pathological mechanisms. For instance, the interplay between integrins and key molecular players such as growth factors, cytokines and enzymes will be summarized. In addition, recent clinical advances linked to targeting RGD-binding integrins in the context of DME and nvAMD will be discussed alongside future potential for limiting progression of these diseases.

Protein kinase A negatively regulates VEGF-induced AMPK activation by phosphorylating CaMKK2 at serine 495

Activation of AMP-activated protein kinase (AMPK) in endothelial cells by vascular endothelial growth factor (VEGF) via the Ca2+/calmodulin-dependent protein kinase kinase 2 (CaMKK2) represents a pro-angiogenic pathway, whose regulation and function is incompletely understood. This study investigates whether the VEGF/AMPK pathway is regulated by cAMP-mediated signalling. We show that cAMP elevation in endothelial cells by forskolin, an activator of the adenylate cyclase, and/or 3-isobutyl-1-methylxanthine (IBMX), an inhibitor of phosphodiesterases, triggers protein kinase A (PKA)-mediated phosphorylation of CaMKK2 (serine residues S495, S511) and AMPK (S487). Phosphorylation of CaMKK2 by PKA led to an inhibition of its activity as measured in CaMKK2 immunoprecipitates of forskolin/IBMX-treated cells. This inhibition was linked to phosphorylation of S495, since it was not seen in cells expressing a non-phosphorylatable CaMKK2 S495C mutant. Phosphorylation of S511 alone in these cells was not able to inhibit CaMKK2 activity. Moreover, phosphorylation of AMPK at S487 was not sufficient to inhibit VEGF-induced AMPK activation in cells, in which PKA-mediated CaMKK2 inhibition was prevented by expression of the CaMKK2 S495C mutant. cAMP elevation in endothelial cells reduced basal and VEGF-induced acetyl-CoA carboxylase (ACC) phosphorylation at S79 even if AMPK was not inhibited. Together, this study reveals a novel regulatory mechanism of VEGF-induced AMPK activation by cAMP/PKA, which may explain, in part, inhibitory effects of PKA on angiogenic sprouting and play a role in balancing pro- and anti-angiogenic mechanisms in order to ensure functional angiogenesis.

Review of Integrin-Targeting Biomaterials in Tissue Engineering

The ability to direct cell behavior has been central to the success of numerous therapeutics to regenerate tissue or facilitate device integration. Biomaterial scientists are challenged to understand and modulate the interactions of biomaterials with biological systems in order to achieve effective tissue repair. One key area of research investigates the use of extracellular matrix-derived ligands to target specific integrin interactions and induce cellular responses, such as increased cell migration, proliferation, and differentiation of mesenchymal stem cells. These integrin-targeting proteins and peptides have been implemented in a variety of different polymeric scaffolds and devices to enhance tissue regeneration and integration. This review first presents an overview of integrin-mediated cellular processes that have been identified in angiogenesis, wound healing, and bone regeneration. Then, research utilizing biomaterials are highlighted with integrin-targeting motifs as a means to direct these cellular processes to enhance tissue regeneration. In addition to providing improved materials for tissue repair and device integration, these innovative biomaterials provide new tools to probe the complex processes of tissue remodeling in order to enhance the rational design of biomaterial scaffolds and guide tissue regeneration strategies.

IFN-I Mediates Dysfunction of Endothelial Progenitor Cells in Atherosclerosis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease including the cardiovascular system. Atherosclerosis is the most common cardiovascular complication of SLE and a significant risk factor for morbidity and mortality. Vascular damage/protection mechanism in SLE patients is out of balance, caused by the cascade reaction among oxidative stress, proinflammatory cytokines, Neutrophil Extracellular Traps, activation of B cells and autoantibodies and abnormal T cells. As a precursor cell repairing vascular endothelium, endothelial progenitor cells (EPCs) belong to the protective mechanism and show the reduced number and impaired function in SLE. However, the pathological mechanism of EPCs dysfunction in SLE remains ill-defined. This paper reviews the latest SLE epidemiology and pathogenesis, discusses the changes in the number and function of EPCs in SLE, expounds the role of EPCs in SLE atherosclerosis, and provides new guidance and theoretical basis for exploring novel targets for SLE treatment.

The Integrin Inhibitor Cilengitide and Bleomycin-Induced Pulmonary Fibrosis : Cilengitide and Bleomycin-Induced Pulmonary Fibrosis

PURPOSE

Fibroproliferation and excess deposition of extracellular matrix (ECM) are the pathologic hallmarks of idiopathic pulmonary fibrosis (IPF), a chronic progressive disorder with high mortality and suboptimal treatment options. Although the etiologic mechanisms responsible for the development and progression of IPF remain unclear, cell-ECM interactions and growth factors are considered important. Cilengitide is a cyclic RGD pentapeptide with anti-angiogenic activity that targets αvβ3, αvβ5 and α5β1, integrins known to mediate cell-ECM interactions and activate the pro-fibrotic growth factor Transforming Growth Factor beta (TGF-β).

METHODS

Cilengitide was studied in vitro with the use of NIH/3T3 cells and primary lung fibroblasts, and in vivo in the well-characterized bleomycin-induced lung injury model. The extent of ECM deposition was determined by RT-PCR, Western blot, histologic analysis and hydroxyproline assay of lung tissue. Bronchoalveolar lavage analysis was used to determine cell counts.

RESULTS

Cilengitide treatment of cultured fibroblasts showed decreased adhesion to vitronectin and fibronectin, both integrin-dependent events. Cilengitide also inhibited TGF-β-induced fibronectin gene expression and reduced the accumulation of mRNAs and protein for fibronectin and collagen type I. Both preventive and treatment effects of daily injections of cilengitide (20 mg/kg) failed to inhibit the development of pulmonary fibrosis as determined by histological analysis (Ashcroft scoring), bronchoalveolar lavage (BAL) fluid cell counts, and hydroxyproline content.

CONCLUSIONS

Overall, our data suggest that, despite its in vitro activity in fibroblasts, daily injections of cilengitide (20 mg/kg) did not inhibit the development of or ameliorate bleomycin-induced pulmonary fibrosis in mice.

NRP2 as an Emerging Angiogenic Player; Promoting Endothelial Cell Adhesion and Migration by Regulating Recycling of α5 Integrin

Angiogenesis relies on the ability of endothelial cells (ECs) to migrate over the extracellular matrix via integrin receptors to respond to an angiogenic stimulus. Of the two neuropilin (NRP) orthologs to be identified, both have been reported to be expressed on normal blood and lymphatic ECs, and to play roles in the formation of blood and lymphatic vascular networks during angiogenesis. Whilst the role of NRP1 and its interactions with integrins during angiogenesis has been widely studied, the role of NRP2 in ECs is poorly understood. Here we demonstrate that NRP2 promotes Rac-1 mediated EC adhesion and migration over fibronectin (FN) matrices in a mechanistically distinct fashion to NRP1, showing no dependence on β3 integrin (ITGB3) expression, or VEGF stimulation. Furthermore, we highlight evidence of a regulatory crosstalk between NRP2 and α5 integrin (ITGA5) in ECs, with NRP2 depletion eliciting an upregulation of ITGA5 expression and disruptions in ITGA5 cellular organization. Finally, we propose a mechanism whereby NRP2 promotes ITGA5 recycling in ECs; NRP2 depleted ECs were found to exhibit reduced levels of total ITGA5 subunit recycling compared to wild-type (WT) ECs. Our findings expose NRP2 as a novel angiogenic player by promoting ITGA5-mediated EC adhesion and migration on FN.

Vascularized human cortical organoids (vOrganoids) model cortical development in vivo

Modeling the processes of neuronal progenitor proliferation and differentiation to produce mature cortical neuron subtypes is essential for the study of human brain development and the search for potential cell therapies. We demonstrated a novel paradigm for the generation of vascularized organoids (vOrganoids) consisting of typical human cortical cell types and a vascular structure for over 200 days as a vascularized and functional brain organoid model. The observation of spontaneous excitatory postsynaptic currents (sEPSCs), spontaneous inhibitory postsynaptic currents (sIPSCs), and bidirectional electrical transmission indicated the presence of chemical and electrical synapses in vOrganoids. More importantly, single-cell RNA-sequencing analysis illustrated that vOrganoids exhibited robust neurogenesis and that cells of vOrganoids differentially expressed genes (DEGs) related to blood vessel morphogenesis. The transplantation of vOrganoids into the mouse S1 cortex resulted in the construction of functional human-mouse blood vessels in the grafts that promoted cell survival in the grafts. This vOrganoid culture method could not only serve as a model to study human cortical development and explore brain disease pathology but also provide potential prospects for new cell therapies for nervous system disorders and injury.

This study establishes a method to generate vascularized cortical organoids. This shows that in addition to reducing hypoxia and cell death, the vascular system promotes neural development in organoids. When transplanting these organoids into host mice, a graft-host vascular system could be reconstructed.

Role of Chemokine (C-X-C Motif) Ligand 10 (CXCL10) in Renal Diseases

Chemokine C-X-C ligand 10 (CXCL10), also known as interferon-γ-inducible protein 10 (IP-10), exerts biological function mainly through binding to its specific receptor, CXCR3. Studies have shown that renal resident mesangial cells, renal tubular epithelial cells, podocytes, endothelial cells, and infiltrating inflammatory cells express CXCL10 and CXCR3 under inflammatory conditions. In the last few years, strong experimental and clinical evidence has indicated that CXCL10 is involved in the development of renal diseases through the chemoattraction of inflammatory cells and facilitation of cell growth and angiostatic effects. In addition, CXCL10 has been shown to be a significant biomarker of disease severity, and it can be used as a prognostic indicator for a variety of renal diseases, such as renal allograft dysfunction and lupus nephritis. In this review, we summarize the structures and biological functions of CXCL10 and CXCR3, focusing on the important role of CXCL10 in the pathogenesis of kidney disease, and provide a theoretical basis for CXCL10 as a potential biomarker and therapeutic target in human kidney disease.

The CC and CXC chemokines: major regulators of tumor progression and the tumor microenvironment

Chemokines are a family of soluble cytokines that act as chemoattractants to guide the migration of cells, in particular of immune cells. However, chemokines are also involved in cell proliferation, differentiation, and survival. Chemokines are associated with a variety of human diseases including chronic inflammation, immune dysfunction, cancer, and metastasis. This review discusses the expression of CC and CXC chemokines in the tumor microenvironment and their supportive and inhibitory roles in tumor progression, angiogenesis, metastasis, and tumor immunity. We also specially focus on the diverse roles of CXC chemokines (CXCL9-11, CXCL4 and its variant CXCL4L1) and their two chemokine receptor CXCR3 isoforms, CXCR3-A and CXCR3-B. These two distinct isoforms have divergent roles in tumors, either promoting (CXCR3-A) or inhibiting (CXCR3-B) tumor progression. Their effects are mediated not only directly in tumor cells but also indirectly via the regulation of angiogenesis and tumor immunity. A full comprehension of their mechanisms of action is critical to further validate these chemokines and their receptors as biomarkers or therapeutic targets in cancer.

Thy-1/CD90 a Bidirectional and Lateral Signaling Scaffold

Thy-1/CD90 is a glycoprotein attached to the outer face of the plasma membrane with various functions, which depend on the context of specific physiological or pathological conditions. Many of these reported functions for Thy-1/CD90 arose from studies by our group, which identified the first ligand/receptor for Thy-1/CD90 as an integrin. This finding initiated studies directed toward unveiling the molecular mechanisms that operate downstream of Thy-1/CD90 activation, and its possible interaction with proteins in the membrane plane to regulate their function. The association of Thy-1/CD90 with a number of cell surface molecules allows the formation of extra/intracellular multiprotein complexes composed of various ligands and receptors, extracellular matrix proteins, intracellular signaling proteins, and the cytoskeleton. The complexes sense changes that occur inside and outside the cells, with Thy-1/CD90 at the core of this extracellular molecular platform. Molecular platforms are scaffold-containing microdomains where key proteins associate to prominently influence cellular processes and behavior. Each component, by itself, is less effective, but when together with various scaffold proteins to form a platform, the components become more specific and efficient to convey the messages. This review article discusses the experimental evidence that supports the role of Thy-1/CD90 as a membrane-associated platform (ThyMAP).

Epac agonist improves barrier function in iPSC-derived endothelial colony forming cells for whole organ tissue engineering

Whole organ engineering paradigms typically involve repopulating acellular organ scaffolds with recipient-compatible cells, to generate a neo-organ that may provide key physiological functions. In the case of whole lung engineering, functionally endothelialized pulmonary vasculature is critical for establishing a fluid-tight barrier at the level of the alveolus, so that oxygen and carbon dioxide can be exchanged in the organ. We have previously developed a protocol to efficiently seed endothelial cells into the microvascular channels of decellularized lung scaffolds, but fully functional endothelial coverage, in terms of barrier function and resistance to thrombosis, was not achieved. In this study, we investigated whether various small molecules could favorably impact endothelial functionality after seeding into decellularized lung scaffolds. We demonstrated that the Epac-selective cAMP analog 8CPT-2Me-cAMP improves endothelial barrier function in repopulated lung scaffolds. When treated with the Epac agonist, barrier function of human umbilical vein endothelial cells (HUVECs) improved, and was maintained for at least three days, whereas the effect of other tested molecules lasted for only 5 h. Treatment with the Epac agonist re-organized actin structure, and appeared to increase the continuity of junction proteins such as VE-cadherin and ZO1. Blockade of actin polymerization abolished the effect of the Epac agonist on barrier function and actin reorganization, confirming a strong actin-mediated effect. Similarly, after treatment with Epac agonist, the barrier function in iPSC-derived endothelial colony forming cells (ECFCs) was increased and the enhanced barrier was maintained for at least 60 h. After culture in lung scaffolds for 5 days, iPSC-ECFCs maintained their phenotype by expressing CD31, eNOS, vWF, and VE-Cadherin. Treatment with the Epac agonist significantly improved the barrier function of iPSC-ECFC-repopulated lung for at least 6 h. Taken together, these findings demonstrated that Epac-selective 8CPT-2Me-cAMP activation enhanced vascular barrier in iPSC-ECFC-engineered lungs, and may be useful to improve endothelial functionality for whole organ tissue engineering.

Cysteine-Based Redox Sensing and Its Role in Signaling by Cyclic Nucleotide-Dependent Kinases in the Cardiovascular System

Oxidant molecules are produced in biological systems and historically have been considered causal mediators of damage and disease. While oxidants may contribute to the pathogenesis of disease, evidence continues to emerge that shows these species also play important regulatory roles in health. A major mechanism of oxidant sensing and signaling involves their reaction with reactive cysteine thiols within proteins, inducing oxidative posttranslational modifications that can couple to altered function to enable homeostatic regulation. Protein kinase A and protein kinase G are regulated by oxidants in this way, and this review focuses on our molecular-level understanding of these events and their role in regulating cardiovascular physiology during health and disease.

Phase I study of the anti-α5β1 monoclonal antibody MINT1526A with or without bevacizumab in patients with advanced solid tumors

PURPOSE

MINT1526A is a monoclonal antibody that blocks the interaction of integrin alpha 5 beta 1 (α5β1) with its extracellular matrix ligands. This phase I study evaluated the safety and pharmacokinetics of MINT1526A with or without bevacizumab in patients with advanced solid tumors.

METHODS

MINT1526A was administered every 3 weeks (Q3W) as monotherapy (arm 1) or in combination with bevacizumab 15 mg/kg, Q3W (arm 2). Each arm included a 3 + 3 dose-escalation stage and a dose-expansion stage.

RESULTS

Twenty-four patients were enrolled in arm 1 (dose range 2-30 mg/kg) and 30 patients were enrolled in arm 2 (dose range 3-15 mg/kg). Monocyte α5β1 receptor occupancy was saturated at a dose of 15 mg/kg. No dose-limiting toxicities were observed, and the maximum tolerated dose was not reached in either arm. The most common adverse events, regardless of causality, included abdominal pain (25%), diarrhea (25%), nausea (21%), vomiting (21%), and fatigue (21%) in arm 1 and nausea (40%), fatigue (33%), vomiting (30%), dehydration (30%), headache (30%), and hypertension (30%) in arm 2. No grade ≥ 3 bleeding events were observed in either arm. No confirmed partial responses (PR) were observed in arm 1. In arm 2, one patient with thymic carcinoma experienced a confirmed PR and two patients with hepatocellular carcinoma (HCC) experienced durable minor radiographic responses.

CONCLUSIONS

MINT1526A, with or without bevacizumab, was well-tolerated. Preliminary evidence of combination efficacy, including in patients with HCC, was observed, but cannot be distinguished from bevacizumab monotherapy in this phase I study.

Biology Informs Treatment Choices in Diffuse Large B Cell Lymphoma

The effective deployment of rationally developed therapies for diffuse large B cell lymphoma (DLBCL) requires rapid assimilation of new biological data. Within this framework, here we address topical issues at the intersection of DLBCL biology and the clinic. We discuss targeting of B cell receptor (BCR) signaling, with emphasis on identifying patients who may benefit from this maneuver and how to best achieve it. We address strategies to modulate the DLBCL microenvironment, including the use of immune checkpoint inhibitors in selected DLBCL subsets, and the potential activity of alternative antiangiogenic therapies. Lastly, we highlight the emerging recognition of MYC and BCL2 coexpression as the most robust predictor of DLBCL outcome, and discuss rationally conceived experimental approaches to treat these high-risk patients.

Ligand activation induces different conformational changes in CXCR3 receptor isoforms as evidenced by plasmon waveguide resonance (PWR)

The chemokine receptor CXCR3 plays important roles in angiogenesis, inflammation and cancer. Activation studies and biological functions of CXCR3 are complex due to the presence of spliced isoforms. CXCR3-A is known as a pro-tumor receptor whereas CXCR3-B exhibits anti-tumor properties. Here, we focused on the conformational change of CXCR3-A and CXCR3-B after agonist or antagonist binding using Plasmon Waveguide Resonance (PWR). Agonist stimulation induced an anisotropic response with very distinct conformational changes for the two isoforms. The CXCR3 agonist bound CXCR3-A with higher affinity than CXCR3-B. Using various concentrations of SCH546738, a CXCR3 specific inhibitor, we demonstrated that low SCH546738 concentrations (≤1 nM) efficiently inhibited CXCR3-A but not CXCR3-B’s conformational change and activation. This was confirmed by both, biophysical and biological methods. Taken together, our study demonstrates differences in the behavior of CXCR3-A and CXCR3-B upon ligand activation and antagonist inhibition which may be of relevance for further studies aimed at specifically inhibiting the CXCR3A isoform.

E-Prostanoid 3 Receptor Mediates Sprouting Angiogenesis Through Suppression of the Protein Kinase A/β-Catenin/Notch Pathway

Objective—

Angiogenesis is a hallmark of embryonic development and various ischemic and inflammatory diseases. Prostaglandin E2 receptor subtype 3 (EP3) plays an important role in pathophysiologic angiogenesis; however, the precise mechanisms remain unknown. Here, we investigated the role of EP3 in zebra fish embryo and mouse retina angiogenesis and evaluated the underlying mechanisms.

Approach and Results—

The EP3 receptor was highly expressed in the vasculature in both zebra fish embryos and murine fetal retinas. Pharmacological inhibition or genetic deletion of EP3 significantly reduced vasculature formation in zebra fish embryos and mouse retinas. Further characterization revealed reduced filopodia extension of tip cells in embryonic retinas in EP3-deficient mice. EP3 deletion activated Notch activity by upregulation of delta-like ligand 4 expression in endothelial cells (ECs). Inhibition of Notch signaling rescued the angiogenic defects in EP3-deficient mouse retinas. Moreover, EP3 deficiency led to a significant increase in β-catenin phosphorylation at Ser675 and nuclear accumulation of β-catenin in ECs. Knockdown or inhibition of β-catenin restored the impaired sprouting angiogenesis resulting from EP3 deficiency in ECs. The EP3 receptor depressed protein kinase A activity in ECs by coupling to Gαi. Inhibition of protein kinase A activity significantly reduced Ser675 phosphorylation and nuclear translocation of β-catenin, abolished the increased delta-like ligand 4 expression, and subsequently restored the impaired angiogenic capacity of EP3-deficient ECs both in vitro and in vivo.

Conclusions—

Activation of the EP3 receptor facilitates sprouting angiogenesis through protein kinase A–dependent Notch signaling, suggesting that EP3 and its downstream pathways maybe potential therapeutic targets in the treatment of ischemic diseases.

Chemokine receptor CXCR3 deficiency exacerbates murine autoimmune cholangitis by promoting pathogenic CD8+ T cell activation

CXC Chemokine Receptor 3 (CXCR3) is functionally pleiotropic and not only plays an important role in chemotaxis, but also participates in T cell differentiation and may play a critical role in inducing and maintaining immune tolerance. These observations are particularly critical for autoimmune cholangitis in which CXCR3 positive T cells are found around the portal areas of both humans and mouse models of primary biliary cholangitis (PBC). Herein, we investigated the role of CXCR3 in the pathogenesis of autoimmune cholangitis. We have taken advantage of a unique CXCR3 knockout dnTGFβRII mouse to focus on the role of CXCR3, both by direct observation of its influence on the natural course of disease, as well as through adoptive transfer studies into Rag-/- mice. We report herein that not only do CXCR3 deficient mice develop an exacerbation of autoimmune cholangitis associated with an expanded effector memory T cell number, but also selective adoptive transfer of CXCR3 deficient CD8⁺ T cells induces autoimmune cholangitis. In addition, gene microarray analysis of CXCR3 deficient CD8⁺ T cells reveal an intense pro-inflammatory profile. Our data suggests that the altered gene profiles induced by CXCR3 deficiency promotes autoimmune cholangitis through pathogenic CD8⁺ T cells. These data have significance for human PBC and other autoimmune liver diseases in which therapeutic intervention might be directed to chemokines and/or their receptors.

Lebecetin, a C-type lectin, inhibits choroidal and retinal neovascularization

Angiogenesis is a cause of visual impairment and blindness in the wet form of age-related macular degeneration and in ischemic retinopathies. Current therapies include use of anti-VEGF agents to reduce choroidal neovascularization (CNV) and edema. These treatments are effective in most cases, but spontaneous or acquired resistance to anti-VEGF and possible adverse effects of long-term VEGF inhibition in the retina and choroid highlight a need for additional alternative therapies. Integrins αvβ3 and αvβ5, which regulate endothelial cell proliferation and stabilization, have been implicated in ocular angiogenesis. Lebecetin (LCT) is a 30-kDa heterodimeric C-type lectin that is isolated from Macrovipera lebetina venom and interacts with α5β1- and αv-containing integrins. We previously showed that LCT inhibits human brain microvascular endothelial cell adhesion, migration, proliferation, and tubulogenesis. To evaluate the inhibitory effect of LCT on ocular angiogenesis, we cultured aortic and choroidal explants in the presence of LCT and analyzed the effect of LCT on CNV in the mouse CNV model and on retinal neovascularization in the oxygen-induced retinopathy model. Our data demonstrate that a single injection of LCT efficiently reduced CNV and retinal neovascularization in these models.-Montassar, F., Darche, M., Blaizot, A., Augustin, S., Conart, J.-B., Millet, A., Elayeb, M., Sahel, J.-A., Réaux-Le Goazigo, A., Sennlaub, F., Marrakchi, N., Messadi, E., Guillonneau, X. Lebecetin, a C-type lectin, inhibits choroidal and retinal neovascularization.

Phosphodiesterase 4 inhibitors have wide-ranging activity in B-cell malignancies

Phosphodiesterase 4 (PDE4) inhibition restores the suppressive effects of 3',5'-cyclic adenosine monophosphate in lymphocytes. In this concise review, we detail how PDE4 inhibition downmodulates the B-cell receptor (BCR)-related kinases spleen tyrosine kinase and phosphatidylinositol 3-kinase and inhibits vascular endothelial growth factor A secretion by tumor cells, inducing cancer cell apoptosis and blocking angiogenesis in the microenvironment. We describe the successful clinical repurposing of PDE4 inhibitors in B-cell malignancies, and propose that given their anti-inflammatory/immunomodulatory activity, these agents will suppress BCR signals without the toxicity associated with other targeted biological doublets.

A phosphodiesterase 4B-dependent interplay between tumor cells and the microenvironment regulates angiogenesis in B-cell lymphoma

Angiogenesis associates with poor outcome in diffuse large B-cell lymphoma (DLBCL), but the contribution of the lymphoma cells to this process remains unclear. Addressing this knowledge gap may uncover unsuspecting proangiogenic signaling nodes and highlight alternative antiangiogenic therapies. Here we identify the second messenger cyclic-AMP (cAMP) and the enzyme that terminates its activity, phosphodiesterase 4B (PDE4B), as regulators of B-cell lymphoma angiogenesis. We first show that cAMP, in a PDE4B-dependent manner, suppresses PI3K/AKT signals to down-modulate VEGF secretion and vessel formation in vitro. Next, we create a novel mouse model that combines the lymphomagenic Myc transgene with germline deletion of Pde4b. We show that lymphomas developing in a Pde4b-null background display significantly lower microvessel density in association with lower VEGF levels and PI3K/AKT activity. We recapitulate these observations by treating lymphoma-bearing mice with the FDA-approved PDE4 inhibitor Roflumilast. Lastly, we show that primary human DLBCLs with high PDE4B expression display significantly higher microvessel density. Here, we defined an unsuspected signaling circuitry in which the cAMP generated in lymphoma cells downmodulates PI3K/AKT and VEGF secretion to negatively influence vessel development in the microenvironment. These data identify PDE4 as an actionable antiangiogenic target in DLBCL.

PKA turnover by the REGγ-proteasome modulates FoxO1 cellular activity and VEGF-induced angiogenesis

The REGγ-proteasome serves as a short-cut for the destruction of certain intact mammalian proteins in the absence of ubiquitin- and ATP. The biological roles of the proteasome activator REGγ are not completely understood. Here we demonstrate that REGγ controls degradation of protein kinase A catalytic subunit-α (PKAca) both in primary human umbilical vein endothelial cells (HUVECs) and mouse embryonic fibroblast cells (MEFs). Accumulation of PKAca in REGγ-deficient HUVECs or MEFs results in phosphorylation and nuclear exclusion of the transcription factor FoxO1, indicating that REGγ is involved in preserving FoxO1 transcriptional activity. Consequently, VEGF-induced expression of the FoxO1 responsive genes, VCAM-1 and E-Selectin, was tightly controlled by REGγ in a PKA dependent manner. Functionally, REGγ is crucial for the migration of HUVECs. REGγ(-/-) mice display compromised VEGF-instigated neovascularization in cornea and aortic ring models. Implanted matrigel plugs containing VEGF in REGγ(-/-) mice induced fewer capillaries than in REGγ(+/+) littermates. Taken together, our study identifies REGγ as a novel angiogenic factor that plays an important role in VEGF-induced expression of VCAM-1 and E-Selectin by antagonizing PKA signaling. Identification of the REGγ-PKA-FoxO1 pathway in endothelial cells (ECs) provides another potential target for therapeutic intervention in vascular diseases.

Role of AKAP 149-PKA-PDE4A complex in cell survival and cell differentiation processes

The cellular localization of A-kinase anchoring proteins (AKAPs), protein kinase A (PKAs) and phosphodiesterases (PDEs) is a key step to the spatiotemporal regulation of the second messenger adenosine 3',5'-cyclic monophosphate (cAMP). In this paper the cellular distribution of the mitochondrial AKAP 149-PKA-PDE4A complex and its implications in the cell death induced by YTX treatment, a known PDE modulator, was studied. K-562 cell line was incubated with YTX for 24 or 48 h. Under these conditions AKAP 149, PKA and type-4A PDE (PDE4A) levels were measured in the cytosol, in the plasma membrane and in the nucleus. Apoptotic hallmarks were also measured after the same conditions. In addition, YTX effect on cell viability was checked after AKAP 149 and PDE4A silencing. The results obtained show a decrease in AKAP 149-PKA-PDE4A levels in cytosol after YTX exposure. 24h after the toxin addition, the complex expression increased in the plasma membrane and after 48 h in the nucleus domain. Furthermore Bcl-2 levels were decreased and the expression of caspase 3 together with caspase 8 activity were increased after 24h of toxin incubation but not after 48 h. These results suggest apoptotic cell death at 24h and a non-apoptotic cell death after 48 h. When AKAP 149 and PDE4A were silenced YTX did not induce cellular death. In summary, AKAP 149-PKA-PDE4A complex localization is related with YTX effect in K-562 cell line. When this complex is mainly located in the plasma membrane apoptosis is activated while when the complex is in the nuclear domain non-apoptotic cellular death or cellular differentiation is activated. Therefore AKAP 149-PKA-PDE4A distribution and integrity have a key role in cellular survival.

Whole genome expression profiling and screening for differentially expressed cytokine genes in human bone marrow endothelial cells treated with humoral inhibitors in liver cirrhosis

Bone marrow endothelial cells (BMECs) are important components of the hematopoietic microenvironment in bone marrow, and they can secrete several types of cytokines to regulate the functions of hematopoietic stem/progenitor cells. To date, it is unknown whether BMECs undergo functional changes and lead to hematopoietic abnormalities in cases of liver cirrhosis (LC). In the present study, whole genome microarray analysis was carried out to detect differentially expressed genes in human BMECs treated for 48 h with medium supplemented with 20% pooled sera from 26 patients with LC or 10 healthy volunteers as the control group. A total of 1,106 upregulated genes and 766 downregulated genes were identified. In Gene Ontology analysis, the most significant categories of genes were revealed. A large number of the upregulated genes were involved in processes, such as cell-cell adhesion, apoptosis and cellular response to stimuli and the downregulated genes were involved in the negative regulation of secretion, angiogenesis, blood vessel development and cell growth. Pathway analysis revealed that the upregulated genes were either cell adhesion molecules or parts of the apoptotic signaling pathway and the downregulated genes were involved in the Wnt signaling pathway and MAPK signaling pathway. These were the pathways with the highest enrichment scores. The results of apoptosis assays revealed that the humoral inhibitors in the sera of patients with LC induced the apoptosis of BMECs, which confirmed the accuracy of bioinformatic analysis. Moreover, we screened and verified 21 differentially expressed cytokine genes [transforming growth factor (TGF)B1, tumor necrosis factor (TNF)B, TNF receptor superfamily, member 11b (TNFRSF11B), TNF (ligand) superfamily, member 13b (TNFSF13B), interleukin (IL)1A, IL6, IL11, IL17C, IL24, family with sequence similarity 3, member B (FAM3B), Fas ligand (FASLG), matrix metallopeptidase (MMP)3, MMP15, vitronectin (VTN), insulin-like growth factor 1 (IGF1), fibroblast growth factor 22 (FGF22), slit homolog 2 (Drosophila) (SLIT2), thrombospondin (THBS)2, THBS3, chemokine (C-C motif) ligand 28 (CCL28) and macrophage stimulating 1 (MST1)] from 97 cytokine genes in BMECs treated with serum from patients with LC. The results from our study demonstrate that the humoral inhibitors in the sera of patients with LC induce the dysfunction and abnormal cytokine secretion by BMECs, which may be a novel mechanism responsible for hematological abnormalities in patients with LC.

CXCR3, a double-edged sword in tumor progression and angiogenesis

CXC chemokines are involved in chemotaxis, regulation of cell growth, induction of apoptosis and modulation of angiostatic effects. CXCL9, CXCL10, CXCL11, CXCL4 and its variant CXCL4L1 are members of the CXC chemokine family, which bind to the CXCR3 receptor to exert their biological effects. These chemokines are associated with a variety of human diseases including chronic inflammation, immune dysfunction, cancer and metastasis. In this review, we focus on accumulating evidence demonstrating the pivotal role of CXCR3 in tumor progression. Its effects are mediated directly in tumor cells or indirectly through the regulation of angiogenesis and tumor immunity. Understanding the emerging role of CXCR3 and its signaling mechanisms further validates this receptor as a biomarker and therapeutic target for tumor progression and tumor angiogenesis.

CREB-binding protein (CBP) regulates β-adrenoceptor (β-AR)-mediated apoptosis

Catecholamines regulate the β-adrenoceptor/cyclic AMP-regulated protein kinase A (cAMP/PKA) pathway. Deregulation of this pathway can cause apoptotic cell death and is implicated in a range of human diseases, such as neuronal loss during aging, cardiomyopathy and septic shock. The molecular mechanism of this process is, however, only poorly understood. Here we demonstrate that the β-adrenoceptor/cAMP/PKA pathway triggers apoptosis through the transcriptional induction of the pro-apoptotic BH3-only Bcl-2 family member Bim in tissues such as the thymus and the heart. In these cell types, the catecholamine-mediated apoptosis is abrogated by loss of Bim. Induction of Bim is driven by the transcriptional co-activator CBP (CREB-binding protein) together with the proto-oncogene c-Myc. Association of CBP with c-Myc leads to altered histone acetylation and methylation pattern at the Bim promoter site. Our findings have implications for understanding pathophysiology associated with a deregulated neuroendocrine system and for developing novel therapeutic strategies for these diseases.

Inhibition of integrins αv/α5-dependent functions in melanoma cells by an ECD-disintegrin acurhagin-C

Acurhagin-C, a Glu-Cys-Asp (ECD)-disintegrin from Agkistrodon acutus venom, has been reported as an endothelial apoptosis inducer, previously. Here we further evaluate its potential applications in cancer therapy. In vitro assays indicated that acurhagin-C not only may influence the cell viability at higher concentration, but also can potently and dose-dependently decrease cell proliferation in murine B16-F10 melanoma. Otherwise, it also had a dose-dependent inhibition on B16-F10 cell adhesion to extracellular matrices, collagen VI, gelatin B and fibronectin, as well as disturbed transendothelial migration of B16-F10 cell. Morphological study found that acurhagin-C dramatically affected B16-F10 cell adhesion to immobilized fibronectin, leading to the formation of multicellular aggregates with rounded shape. Detected by flow cytometry, acurhagin-C was able to induce B16-F10 cell apoptosis and alter cell cycle distribution through its interactions with integrins αv/α5, and thereafter initiation the apoptotic pathways of caspase-8/-9. Furthermore, acurhagin-C could synergistically enhance the anti-proliferative activity of methotrexate in B16-F10 cells and human melanoma SK-MEL-1 cells, without diminishing the growth of human epidermal melanocytes. Taken together, acurhagin-C proved to be a potent inhibitor of integrin-based functions in melanoma cells by activating the complex apoptotic pathways.

Integrin α5β1, the Fibronectin Receptor, as a Pertinent Therapeutic Target in Solid Tumors

Integrins are transmembrane heterodimeric proteins sensing the cell microenvironment and modulating numerous signalling pathways. Changes in integrin expression between normal and tumoral cells support involvement of specific integrins in tumor progression and aggressiveness. This review highlights the current knowledge about α5β1 integrin, also called the fibronectin receptor, in solid tumors. We summarize data showing that α5β1 integrin is a pertinent therapeutic target expressed by tumoral neovessels and tumoral cells. Although mainly evaluated in preclinical models, α5β1 integrin merits interest in particular in colon, breast, ovarian, lung and brain tumors where its overexpression is associated with a poor prognosis for patients. Specific α5β1 integrin antagonists will be listed that may represent new potential therapeutic agents to fight defined subpopulations of particularly aggressive tumors.

Emerging role of PKA/eNOS pathway in therapeutic angiogenesis for ischaemic tissue diseases

Although an abundant amount of research has been devoted to the study of angiogenesis, its precise mechanisms are incompletely understood. Numerous clinical trials focused on therapeutic angiogenesis for the treatment of tissue ischaemia have not been as successful as those of preclinical studies. Thus, additional studies are needed to better understand critical molecular mechanisms regulating ischaemic neovascularization to identify novel therapeutic agents. Nitric oxide (NO) plays a central role in ischaemic neovascularization through the generation of cyclic guanosine monophosphate (cGMP) and the activation of several other signalling responses. Accumulated evidence suggests that endothelial protein kinase A/endothelial NO synthase (PKA/eNOS) signalling may play an important role in ischaemic disorders by promoting neovascularization. This review highlights recent advances in the role of the PKA/eNOS and NO-cGMP-kinase cascade pathway in ischaemic neovascularization. We also discuss molecular relationships of PKA/eNOS with other angiogenic pathways and explore the possibility of activation of the NO/nitrite endocrine system as potential therapeutic targets for ischaemic angiogenesis.

CXCL10: a candidate biomarker in transplantation

Interferon (IFN) γ-induced protein 10 kDa (IP-10) or C-X-C motif chemokine 10 (CXCL10) is a small cytokine belonging to the CXC chemokine family. This family of signaling molecules is known to control several biological functions and to also play pivotal roles in disease initiation and progression. By binding to its specific cognate receptor CXCR3, CXCL10 critically regulates chemotaxis during several immune-inflammatory processes. In particular, this chemokine controls chemotaxis during the inflammatory response resulting from allograft rejection after transplantation. Interestingly, a strong association has been described between CXCL10 production, immune response and the fate of the graft following allotransplantation. Enhanced CXCL10 production has been observed in recipients of transplants of different organs. This enhanced production likely comes from either the graft or the immune cells and is correlated with an increase in the concentration of circulating CXCL10. Because CXCL10 can be easily measured in the serum and plasma from a patient, the detection and quantitation of circulating CXCL10 could be used to reveal a transplant recipient's immune status. The purpose of this review is to examine the critical role of CXCL10 in the pathogenesis of allograft rejection following organ transplantation. This important role highlights the potential utilization of CXCL10 not only as a therapeutic target but also as a biomarker to predict the severity of rejection, to monitor the inflammatory status of organ recipients and, hopefully, to fine-tune patient therapy in transplantation.

ZEB2 upregulates integrin α5 expression through cooperation with Sp1 to induce invasion during epithelial-mesenchymal transition of human cancer cells

Epithelial-mesenchymal transition (EMT) is a process implicated in tumor invasion, metastasis, embryonic development and wound healing. ZEB2 is a transcription factor involved in EMT that represses E-cadherin transcription. Although E-cadherin downregulation is a major event during EMT and tumor progression, E-cadherin reduction is probably not sufficient for full invasiveness. The mechanisms by which E-cadherin transcriptional repressors induce mesenchymal genes during EMT remain largely unknown. Here, we investigated the role of ZEB2 in the induction of integrin α5 during cancer EMT and its underlying mechanism. In human cancer cells, ZEB2 was found to directly upregulate integrin α5 transcription in a manner that is independent of the regulation of E-cadherin expression. Conversely, depletion of ZEB2 by small interfering RNA suppressed integrin α5 expression, leading to reduced invasion. Suppression of integrin α5 inhibited cancer cell invasion, suggesting an important role for integrin α5 in cancer progression. Furthermore, ZEB2 was found to activate the integrin α5 and vimentin promoters by interacting with and activating the transcription factor Sp1, suggesting that cooperation between ZEB2 and Sp1 represents a novel mechanism of mesenchymal gene activation during EMT. These findings increase our understanding of the pathways beyond E-cadherin reduction that regulate mesenchymal gene expression during EMT and cancer progression.

Targeting of α(v)-integrins in stem/progenitor cells and supportive microenvironment impairs bone metastasis in human prostate cancer

Acquisition of an invasive phenotype by cancer cells is a requirement for bone metastasis. Transformed epithelial cells can switch to a motile, mesenchymal phenotype by epithelial-mesenchymal transition (EMT). Recently, it has been shown that EMT is functionally linked to prostate cancer stem cells, which are not only critically involved in prostate cancer maintenance but also in bone metastasis. We showed that treatment with the non-peptide α(v)-integrin antagonist GLPG0187 dose-dependently increased the E-cadherin/vimentin ratio, rendering the cells a more epithelial, sessile phenotype. In addition, GLPG0187 dose-dependently diminished the size of the aldehyde dehydrogenase high subpopulation of prostate cancer cells, suggesting that α(v)-integrin plays an important role in maintaining the prostate cancer stem/progenitor pool. Our data show that GLPG0187 is a potent inhibitor of osteoclastic bone resorption and angiogenesis in vitro and in vivo. Real-time bioluminescent imaging in preclinical models of prostate cancer demonstrated that blocking α(v)-integrins by GLPG0187 markedly reduced their metastatic tumor growth according to preventive and curative protocols. Bone tumor burden was significantly lower in the preventive protocol. In addition, the number of bone metastases/mouse was significantly inhibited. In the curative protocol, the progression of bone metastases and the formation of new bone metastases during the treatment period was significantly inhibited. In conclusion, we demonstrate that targeting of integrins by GLPG0187 can inhibit the de novo formation and progression of bone metastases in prostate cancer by antitumor (including inhibition of EMT and the size of the prostate cancer stem cell population), antiresorptive, and antiangiogenic mechanisms.

PRKX critically regulates endothelial cell proliferation, migration, and vascular-like structure formation

Angiogenesis is a fundamental step in several important physiological events and pathological conditions including embryonic development, wound repair, tumor growth and metastasis. PRKX was identified as a novel type-I cAMP-dependent protein kinase gene expressed in multiple developing tissues. PRKX has also been shown to be phylogenetically and functionally distinct from PKA. This study presents the first evidence that PRKX stimulates endothelial cell proliferation, migration, and vascular-like structure formation, which are the three essential processes for angiogenesis. In contrast, classic PKA demonstrated an inhibitory effect on endothelia vascular-like structure formation. Our findings suggest that PRKX is an important protein kinase engaged in the regulation of angiogenesis and could play critical roles in various physiological and pathological conditions involving angiogenesis. PRKX binds to Pin-1, Magi-1 and Bag-3, which regulate cell proliferation, apoptosis, differentiation and tumorigenesis. The interaction of PRKX with Pin-1, Magi-1 and Bag-3 could contribute to the stimulating role of PRKX in angiogenesis.

CXCL10/IP-10 in infectious diseases pathogenesis and potential therapeutic implications

C-X-C motif chemokine 10 (CXCL10) also known as interferon γ-induced protein 10 kDa (IP-10) or small-inducible cytokine B10 is a cytokine belonging to the CXC chemokine family. CXCL10 binds CXCR3 receptor to induce chemotaxis, apoptosis, cell growth and angiostasis. Alterations in CXCL10 expression levels have been associated with inflammatory diseases including infectious diseases, immune dysfunction and tumor development. CXCL10 is also recognized as a biomarker that predicts severity of various diseases. A review of the emerging role of CXCL10 in pathogenesis of infectious diseases revealed diverse roles of CXCL10 in disease initiation and progression. The potential utilization of CXCL10 as a therapeutic target for infectious diseases is discussed.

Pharmacoproteomic analysis of a novel cell-permeable peptide inhibitor of tumor-induced angiogenesis

P11, a novel peptide ligand containing a PDZ-binding motif (Ser-Asp-Val) with high affinity to integrin α(v)β(3) was identified from a hexapeptide library (PS-SPCL) using a protein microarray chip-based screening system. Here, we investigated the inhibitory mechanism of P11 (HSDVHK) on tumor-induced angiogenesis via a pharmacoproteomic approach. P11 was rapidly internalized by, human umbilical vein endothelial cells (HUVECs) via an integrin α(v)β(3)-mediated event. Caveolin and clathrin appeared to be involved in the P11 uptake process. The cell-penetrating P11 resulted in suppression of bFGF-induced HUVEC proliferation in a dose-dependent manner. Phosphorylation of extracellular-signal regulated kinase (ERK1/2) and mitogen-activated protein kinase kinase (MEK) in bFGF-stimulated HUVECs was inhibited by cell-permeable P11. Proteomic analysis via antibody microarray showed up-regulation of p53 in P11-treated HUVECs, resulting in induction of apoptosis via activation of caspases-3, -8, and -9. Several lines of experimental evidence strongly suggest that the molecular mechanism of P11, a novel anti-angiogenic agent, inhibits bFGF-induced HUVEC proliferation via mitogen-activated protein kinase kinase and extracellular-signal regulated kinase inhibition as well as p53-mediated apoptosis related with activation of caspases.

The emerging role of CXCL10 in cancer (Review)

The chemokine interferon-γ inducible protein 10 kDa (CXCL10) is a member of the CXC chemokine family which binds to the CXCR3 receptor to exert its biological effects. CXCL10 is involved in chemotaxis, induction of apoptosis, regulation of cell growth and mediation of angiostatic effects. CXCL10 is associated with a variety of human diseases including infectious diseases, chronic inflammation, immune dysfuntion, tumor development, metastasis and dissemination. More importantly, CXCL10 has been identified as a major biological marker mediating disease severity and may be utilized as a prognostic indicator for various diseases. In this review, we focus on current research elucidating the emerging role of CXCL10 in the pathogenesis of cancer. Understanding the role of CXCL10 in disease initiation and progression may provide the basis for developing CXCL10 as a potential biomarker and therapeutic target for related human malignancies.