IFN-gamma acts as anti-angiogenic cytokine in the human cornea by regulating the expression of VEGF-A and sVEGF-R1

Gut microbiome-derived butyrate inhibits the immunosuppressive factors PD-L1 and IL-10 in tumor-associated macrophages in gastric cancer

Early detection and surgical treatment are essential to achieve a good outcome in gastric cancer (GC). Stage IV and recurrent GC have a poor prognosis. Therefore, new treatments for GC are needed. We investigated the intestinal microbiome of GC patients and attempted to reverse the immunosuppression of the immune and cancer cells of GC patients through the modulation of microbiome metabolites. We evaluated the levels of programmed death-ligand 1 (PD-L1) and interleukin (IL)-10 in the peripheral blood immunocytes of GC patients. Cancer tissues were obtained from patients who underwent surgical resection of GC, and stained sections of cancer tissues were visualized via confocal microscopy. The intestinal microbiome was analyzed using stool samples of healthy individuals and GC patients. Patient-derived avatar model was developed by injecting peripheral blood mononuclear cells (PBMCs) from advanced GC (AGC) patients into NSG mice, followed by injection of AGS cells. PD-L1 and IL-10 had higher expression levels in immune cells of GC patients than in those of healthy controls. The levels of immunosuppressive factors were increased in the immune and tumor cells of tumor tissues of GC patients. The abundances of Faecalibacterium and Bifidobacterium in the intestinal flora were lower in GC patients than in healthy individuals. Butyrate, a representative microbiome metabolite, suppressed the expression levels of PD-L1 and IL-10 in immune cells. In addition, the PBMCs of AGC patients showed increased levels of immunosuppressive factors in the avatar mouse model. Butyrate inhibited tumor growth in mice. Restoration of the intestinal microbiome and its metabolic functions inhibit tumor growth and reverse the immunosuppression due to increased PD-L1 and IL-10 levels in PBMCs and tumor cells of GC patients.

Macrophages in the process of osseointegration around the implant and their regulatory strategies

PURPOSE/AIM OF THE STUDY

To summarize and discuss macrophage properties and their roles and mechanisms in the process of osseointegration in a comprehensive manner, and to provide theoretical support and research direction for future implant surface modification efforts.

MATERIALS AND METHODS

Based on relevant high-quality articles, this article reviews the role of macrophages in various stages of osseointegration and methods of implant modification.

RESULTS AND CONCLUSIONS

Macrophages not only promote osseointegration through immunomodulation, but also secrete a variety of cytokines, which play a key role in the angiogenic and osteogenic phases of osseointegration. There is no "good" or "bad" difference between the M1 and M2 phenotypes of macrophages, but their timely presence and sequential switching play a crucial role in implant osseointegration. In the implant surface modification strategy, the induction of sequential activation of the M1 and M2 phenotypes of macrophages is a brighter prospect for implant surface modification than inducing the polarization of macrophages to the M1 or M2 phenotypes individually, which is a promising pathway to enhance the effect of osseointegration and increase the success rate of implant surgery.

Insights into the role of DNA methylation and gene expression in Graves' orbitopathy

CONTEXT

A role of DNA methylation in Graves' orbitopathy (GO) has been proposed. Design. To investigate DNA methylation and gene expression in orbital fibroblasts from control and GO patients, under basal conditions or following challenge with an anti-TSH receptor antibody (M22) or cytokines involved in GO; to investigate the relationship between DNA methylation and cell function (proliferation); to perform a methylome analysis. Setting. Referral Center. Materials. Orbital fibroblasts from six GO and six control patients. Intervention. None. Main Outcome Measure. Methylome analysis of the whole genome. Results. Global DNA methylation increased significantly both in control and GO fibroblasts upon incubation with M22. Expression of two selected genes (CYP19A1 and AIFM2) was variably affected by M22 and interleukin-6. M22 increased cell proliferation in control and GO fibroblasts, which correlated with global DNA methylation. Methylome analysis revealed 19,869 DNA regions differently methylated in GO fibroblasts, encompassing 3,957 genes and involving CpG islands, shores and shelves. One-hundred and nineteen gene families and subfamilies, 89 protein groups, 402 biological processes and seven pathways were involved. Three genes found to be differentially expressed were concordantly hyper- or hypomethylated. Among the differently methylated genes, insulin-like growth factor-1 receptor and several fibroblast growth factors and receptors were included.

CONCLUSIONS

We propose that, when exposed to an autoimmune environment, orbital fibroblasts undergo hyper- or hypomethylation of certain genes, involving CpG promoters, which results in differential gene expression, which may be responsible for functional alterations, in particular higher proliferation, and ultimately for the GO phenotype in vivo.

Interferon γ neutralization reduces blood pressure, uterine artery resistance index, and placental oxidative stress in placental ischemic rats

Preeclampsia (PE) is characterized by maternal hypertension, intrauterine growth restriction, and increased cytolytic natural killer cells (cNKs), which secrete interferon γ (IFNγ). However, the precise role of IFNγ in contributing to PE pathophysiology remains unclear. Using the reduced uterine perfusion pressure (RUPP) rat model of placental ischemia, we tested the hypothesis that neutralization of IFNγ in RUPPs will decrease placental reactive oxygen species (ROS) and improve vascular function resulting in decreased MAP and improved fetal growth. On gestation day (GD) 14, the RUPP procedure was performed and on GDs 15 and 18, a subset of normal pregnant rats (NP) and RUPP rats were injected with 10 μg/kg of an anti-rat IFNγ monoclonal antibody. On GD 18, uterine artery resistance index (UARI) was measured via Doppler ultrasound and on GD 19, mean arterial pressure (MAP) was measured, animals were euthanized, and blood and tissues were collected for analysis. Increased MAP was observed in RUPP rats compared with NP and was reduced in RUPP + anti-IFNγ. Placental ROS was also increased in RUPP rats compared with NP rats and was normalized in RUPP + anti-IFNγ. Fetal and placental weights were reduced in RUPP rats, but were not improved following anti-IFNγ treatment. However, UARI was elevated in RUPP compared with NP rats and was reduced in RUPP + anti-IFNγ. In conclusion, we observed that IFNγ neutralization reduced MAP, UARI, and placental ROS in RUPP recipients. These data suggest that IFNγ is a potential mechanism by which cNKs contribute to PE pathophysiology and may represent a therapeutic target to improve maternal outcomes in PE.

Double-edged effects of interferons on the regulation of cancer-immunity cycle

Interferons (IFNs) are a large family of pleiotropic cytokines that regulate both innate and adaptive immunity and show anti-cancer effects in various cancer types. Moreover, it was revealed that IFN signaling plays critical roles in the success of cancer therapy strategies, thereby enhancing their therapeutic effects. However, IFNs have minimal or even adverse effects on cancer eradication, and mediate cancer immune escape in some instances. Thus, IFNs have a double-edged effect on the cancer immune response. Recent studies suggest that IFNs regulate each step of the cancer immunity-cycle, consisting of cancer antigen release, presentation of antigens and activation of T cells, trafficking and infiltration of effector T cells into the tumor microenvironment, and recognition and killing of cancer cells, which contributes to our understanding of the mechanisms of IFNs in regulating cancer immunity. In this review, we focus on IFNs and cancer immunity and elaborate on the roles of IFNs in regulating the cancer-immunity cycle.

Corneal angiogenic privilege and its failure

The cornea actively maintains its own avascular status to preserve its ultimate optical function. This corneal avascular state is also defined as "corneal angiogenic privilege", which results from a critical and sensitive balance between anti-angiogenic and pro-angiogenic mechanisms. In our review, we aim to explore the complex equilibrium among multiple mediators which prevents neovascularization in the resting cornea, as well as to unveil the evolutive process which leads to corneal angiogenesis in response to different injuries.

Loss of FOXC1 contributes to the corneal epithelial fate switch and pathogenesis

Forkhead box C1 (FOXC1) is required for neural crest and ocular development, and mutations in FOXC1 lead to inherited Axenfeld-Rieger syndrome. Here, we find that FOXC1 and paired box 6 (PAX6) are co-expressed in the human limbus and central corneal epithelium. Deficiency of FOXC1 and alternation in epithelial features occur in patients with corneal ulcers. FOXC1 governs the fate of the corneal epithelium by directly binding to lineage-specific open promoters or enhancers marked by H3K4me2. FOXC1 depletion not only activates the keratinization pathway and reprograms corneal epithelial cells into skin-like epithelial cells, but also disrupts the collagen metabolic process and interferon signaling pathways. Loss of interferon regulatory factor 1 and PAX6 induced by FOXC1 dysfunction is linked to the corneal ulcer. Collectively, our results reveal a FOXC1-mediated regulatory network responsible for corneal epithelial homeostasis and provide a potential therapeutic target for corneal ulcer.

The Effect of Androgens on Proinflammatory Cytokine Secretion from Human Ocular Surface Epithelial Cells

Purpose: The purpose of this study is to explore the effects of dihydrotestosterone (DHT) on lipopolysaccharide (LPS)-induced proinflammatory cytokine release in human ocular surface epithelial cells exposed to LPS and LPS-binding protein (LBP).Methods: Immortalized human corneal, conjunctival, and meibomian gland epithelial cells were cultured in keratinocyte-free medium. After confluency, they were exposed to a stratification medium Dulbecco's modified Eagle medium (DMEM)/F12 in the presence of fetal bovine serum and were exposed to vehicle, LPS + LBP, or DHT. Culture media were processed for multiplex-bead analysis of specific proinflammatory cytokines including interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-2, IL-4, IL-8, IL-6, IL-10, IL-1β, vascular endothelial growth factor (VEGF)-A. Cytokine concentrations were compared by analysis of variance with Tukey post hoc testing. p < 0.05 was considered statistically significant.Results: The results are LPS + LBP-induced the secretion of IFN-γ, IL-6, IL-10, IL-1β, VEGF-A cytokines in corneal epithelial cells; TNF-α, IL-2, IL-8, IL-6, IL-1β, VEGF-A cytokines in conjunctival epithelial cells; and IL-8, IL-6, IL-1β, VEGF-A cytokines in meibomian gland epithelial cells. When these LPS + LBP-stimulated cells were exposed to DHT for 2 days, it was found that DHT suppressed the secretion of IL-6, IL-10, IL-1β, VEGF-A cytokines in corneal epithelial cells; TNF-α, IL-6, IL-1β, VEGF-A cytokines in conjunctival epithelial cells; and IL-6, IL-1β, VEGF-A cytokines in meibomian gland epithelial cells.Conclusion: LPS + LBP is shown to induce the secretion of certain proinflammatory cytokines from ocular surface and adnexal epithelial cells. DHT showed anti-inflammatory activity by suppressing some of those cytokines in these cell lines.

Epithelial Membrane Protein-2 (EMP2) Antibody Blockade Reduces Corneal Neovascularization in an In Vivo Model

Purpose

Pathologic corneal neovascularization is a major cause of blindness worldwide, and treatment options are currently limited. VEGF is one of the critical mediators of corneal neovascularization but current anti-VEGF therapies have produced limited results in the cornea. Thus, additional therapeutic agents are needed to enhance the antiangiogenic arsenal. Our group previously demonstrated epithelial membrane protein-2 (EMP2) involvement in pathologic angiogenesis in multiple cancer models including breast cancer and glioblastoma. In this paper, we investigate the efficacy of anti-EMP2 immunotherapy in the prevention of corneal neovascularization.

Methods

An in vivo murine cornea alkali burn model was used to study pathologic neovascularization. A unilateral corneal burn was induced using NaOH, and subconjunctival injection of either anti-EMP2 antibody, control antibody, or sterile saline was performed after corneal burn. Neovascularization was clinically scored at 7 days postalkali burn, and eyes were enucleated for histologic analysis and immunostaining including VEGF, CD31, and CD34 expression.

Results

Anti-EMP2 antibody, compared to control antibody or vehicle, significantly reduced neovascularization as measured by clinical score and central cornea thickness, as well as by histologic reduction of neovascularization, decreased CD34 staining, and decreased CD31 staining. Incubation of corneal limbal cells in vitro with anti-EMP2 blocking antibody significantly decreased EMP2 expression, VEGF expression and secretion, and cell migration.

Conclusions

This work demonstrates the effectiveness of EMP2 as a novel target in pathologic corneal neovascularization in an animal model and supports additional investigation into EMP2 antibody blockade as a potential new therapeutic option.

NK Cells Control Tumor-Promoting Function of Neutrophils in Mice

Although natural killer (NK) cells are recognized as direct antitumor effectors, the ability of NK cells to control cancer-associated inflammation, which facilitates tumor progression, remains unknown. In this study, we demonstrate that NK cells control tumor-promoting inflammation through functional modification of neutrophils. NK cells control the tumor-promoting function of neutrophils through an IFNγ-dependent mechanism. Tumor progression in an NK cell-depleted host is diminished when the IL17A-neutrophil axis is absent. In NK cell-depleted mice, neutrophils acquire a tumor-promoting phenotype, characterized by upregulation of VEGF-A expression, which promotes tumor growth and angiogenesis. A VEGFR inhibitor which preferentially suppressed tumor growth in NK cell-depleted mice was dependent on neutrophils. Furthermore, the systemic neutropenia caused by an antimetabolite treatment showed an anticancer effect only in mice lacking NK cells. Thus, NK cells likely control the tumor-promoting and angiogenic function of neutrophils. Cancer Immunol Res; 6(3); 348-57. ©2018 AACR.

Corneal Mesenchymal Stromal Cells Are Directly Antiangiogenic via PEDF and sFLT-1

Purpose

To evaluate the angiogenic properties of corneal derived mesenchymal stromal cells (Co-MSC).

Methods

Co-MSCs were extracted from human cadaver, and wild-type (C57BL/6J) and SERPINF1^−/− mice corneas. The MSC secretome was collected in a serum-free medium. Human umbilical vein endothelial cell (HUVEC) tube formation and fibrin gel bead assay (FIBA) sprout formation were used to assess the angiogenic properties of Co-MSC secretome. Complete corneal epithelial debridement was used to induce corneal neovascularization in wild-type mice. Co-MSCs embedded in fibrin gel was applied over the debrided cornea to evaluate the angiogenic effects of Co-MSCs in vivo. Immunoprecipitation was used to remove soluble fms-like tyrosine kinase-1 (sFLT-1) and pigment epithelium-derived factor (PEDF, SERPINF1 gene) from the Co-MSC secretome.

Results

Co-MSC secretome significantly inhibited HUVECs tube and sprout formation. Co-MSCs from different donors consistently contained high levels of antiangiogenic factors including sFLT-1 and PEDF; and low levels of the angiogenic factor VEGF-A. In vivo, application of Co-MSCs to mouse corneas after injury prevented the development of corneal neovascularization. Removing PEDF or sFLT-1 from the secretome significantly diminished the antiangiogenic effects of Co-MSCs. Co-MSCs isolated from SERPINF1^−/− mice had significantly reduced antiangiogenic effects compared to SERPINF1^+/+ (wild-type) Co-MSCs.

Conclusions

These results illustrate the direct antiangiogenic properties of Co-MSCs, the importance of sFLT-1 and PEDF, and their potential clinical application for preventing pathologic corneal neovascularization.

Proangiogenic Function of T Cells in Corneal Transplantation

BACKGROUND

Corneal neovascularization increases the risk of T cell-mediated allograft rejection. Here, we investigate whether T cells promote angiogenesis in transplantation.

METHODS

Conventional effector T cells were collected from draining lymph nodes of allogeneic or syngeneic corneal transplanted BALB/c mice. T cells were either cocultured with vascular endothelial cells (VECs) to assess VEC proliferation or used in a mixed lymphocyte reaction assay. Messenger RNA (mRNA) expression of vascular endothelial growth factor (VEGF)-A, -C, and VEGF receptor 2 (VEGF-R2) in VECs was assessed by real-time PCR. VEGF-A protein expression was determined by enzyme-linked immunosorbent assay. Flow cytometry was used to analyze VEGF-R2 expression in corneal CD31 cells, and VEGF-A and IFNγ expression in corneal CD4 T cells.

RESULTS

Allogeneic T cells from high-risk (HR) grafted mice induced more VEC proliferation than those from syngeneic transplant recipients (P = 0.03). Vascular endothelial growth factor-A mRNA and protein expression were higher in T cells from draining lymph nodes (P = 0.03 and P = 0.04, respectively) and cornea (protein; P = 0.04) of HR compared with low-risk (LR) grafted hosts. Vascular endothelial growth factor-A, VEGF-C, and VEGF-R2 mRNA expression were increased in VECs when cocultured with T cells from HR transplants compared with LR transplants and naive mice. In addition, IFNγ blockade in T cell/VEC coculture increased VEC proliferation and VEGF-A protein expression, whereas blocking VEGF-A significantly reduced VEC proliferation (P = 0.04).

CONCLUSIONS

Allogeneic T cells from corneal transplant hosts promote VEC proliferation, probably via VEGF-A signaling, whereas IFNγ shows an antiangiogenic effect. Our data suggest that T cells are critical mediators of angiogenesis in transplantation.

Inflammatory cytokines regulate secretion of VEGF and chemokines by human conjunctival fibroblasts: Role in dysfunctional tear syndrome

Ocular surface inflammation is one of the primary mechanisms associated with dysfunctional tear syndrome (DTS), also known as dry eye disease. DTS, more prevalent in older populations, causes ocular discomfort and visual disturbance due to dryness on the surface layer in the eye. We used human conjunctival fibroblast cultures (HCJVF) to investigate the effects of inflammatory cytokines IFN-γ, TNF-α and IL-1β (ITI) on the secretions of VEGF and chemokines. Our results demonstrate the elevated secretion of angiogenic VEGF molecules by ITI without affecting anti-angiogenic molecules, PEDF, endostatin, thrombospondin and sVEGF-R1. The secretion of interferon-γ inducible chemokines, CXCL9, -10, -11 by HCJVF were significantly enhanced by ITI. Our in vitro study supports previously reported observations of elevated VEGF and chemokines in tear fluids of DTS patients, reiterating the role of inflammatory reactions in DTS.

The Interplay Between Monocytes/Macrophages and CD4(+) T Cell Subsets in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by inflammation of the synovial lining (synovitis). The inflammation in the RA joint is associated with and driven by immune cell infiltration, synovial hyperproliferation, and excessive production of proinflammatory mediators, such as tumor necrosis factor α (TNFα), interferon γ (IFNγ), interleukin (IL)-1β, IL-6, and IL-17, eventually resulting in damage to the cartilage and underlying bone. The RA joint harbors a wide range of immune cell types, including monocytes, macrophages, and CD4(+) T cells (both proinflammatory and regulatory). The interplay between CD14(+) myeloid cells and CD4(+) T cells can significantly influence CD4(+) T cell function, and conversely, effector vs. regulatory CD4(+) T cell subsets can exert profound effects on monocyte/macrophage function. In this review, we will discuss how the interplay between CD4(+) T cells and monocytes/macrophages may contribute to the immunopathology of RA.

IL-4 regulates specific Arg-1(+) macrophage sFlt-1-mediated inhibition of angiogenesis

One of the main drivers for neovascularization in age-related macular degeneration is activation of innate immunity in the presence of macrophages. Here, we demonstrate that T helper cell type 2 cytokines and, in particular, IL-4 condition human and murine monocyte phenotype toward Arg-1(+), and their subsequent behavior limits angiogenesis by increasing soluble fms-like tyrosine kinase 1 (sFlt-1) gene expression. We document that T helper cell type 2 cytokine-conditioned murine macrophages neutralize vascular endothelial growth factor-mediated endothelial cell proliferation (human umbilical vein endothelial cell and choroidal vasculature) in a sFlt-1-dependent manner. We demonstrate that in vivo intravitreal administration of IL-4 attenuates laser-induced choroidal neovascularization (L-CNV) due to specific IL-4 conditioning of macrophages. IL-4 induces the expression of sFlt-1 by resident CD11b(+) retinal microglia and infiltrating myeloid cells but not from retinal pigment epithelium. IL-4-induced suppression of L-CNV is not prevented when sFlt-1 expression is attenuated in retinal pigment epithelium. IL-4-mediated suppression of L-CNV was abrogated in IL-4R-deficient mice and in bone marrow chimeras reconstituted with myeloid cells that had undergone lentiviral-mediated shRNA silencing of sFlt-1, demonstrating the critical role of this cell population. Together, these data establish how lL-4 directly drives macrophage sFlt-1 production expressing an Arg-1(+) phenotype and support the therapeutic potential of targeted IL-4 conditioning within the tissue to regulate disease conditions such as neovascular age-related macular degeneration.

Regulation of indoleamine 2,3-dioxygenase in primary human saphenous vein endothelial cells

BACKGROUND

Indoleamine 2,3-dioxygenase (IDO) is an enzyme associated with the regulation of immune responses. Cytokines such as IFNγ induce its expression in endothelial cells originating from immune-privileged sites. In this study, we investigate regulators of IDO in primary endothelial cells from a non-immune-privileged site and determine whether IDO expression affects immune cell behavior.

METHODS

IDO expression was determined using real-time quantitative polymerase chain reaction and immunoblotting. IDO activity was estimated using an IDO enzyme assay. Primary cells were transfected using microporation, and T-cell migration was determined using a cell transmigration assay.

RESULTS

IDO is expressed in human saphenous vein endothelial cells after stimulation with IFNγ but not after treatment with TNFα, IL-1β, IL-2, IL-4, IL-6, or IL-10. VEGFβ and heparin negatively regulate IFNγ-driven increases in IDO. Overexpression of IDO in endothelial cells does not affect transmigration of T-cells.

CONCLUSION

IDO is expressed in human saphenous vein endothelial cells after stimulation with IFNγ. Heparin and angiogenesis stimulators such as VEGFβ negatively regulate its expression.

Fibromodulin Enhances Angiogenesis during Cutaneous Wound Healing

Supplemental Digital Content is available in the text.

Background:

Fibromodulin (FMOD) plays a critical role in the wound-healing process. Our previous studies revealed that FMOD deficiency led to marked alterations in adult wound healing characterized by delayed dermal cell migration, postponed wound closure, and increased scar formation, all accompanied by impeded angiogenesis. Therefore, the aim of this study was to reveal the effect of FMOD on angiogenesis during the wound-healing process.

Methods:

In vivo angiogenic effects of FMOD were assessed by a chick embryo chorioallantoic membrane assay, a Matrigel (BD Bioscience, Franklin Lakes, N.J.) plug implant assay, and rodent primary closure wound models. In vitro angiogenic effects of FMOD were recorded by cell invasion and dimensional and topological parameters of human umbilical vein endothelial cells.

Results:

We provided evidence that FMOD significantly enhanced vascularization: first, FMOD boosted blood vessel formation on the chorioallantoic membrane; second, FMOD markedly stimulated capillary infiltration into Matrigel plugs subcutaneously implanted in adult mice; and finally, FMOD robustly promoted angiogenesis in multiple adult rodent cutaneous wound models. Furthermore, FMOD administration restored the vascularity of fmod^−/− mouse wounds. In support of this, FMOD endorsed an angiogenesis-favored microenvironment in adult rodent wounds not only by upregulating angiogenic genes but also by downregulating angiostatic genes. In addition, FMOD significantly enhanced human umbilical vein endothelial cell invasion and tube-like structure formation in vitro.

Conclusions:

Altogether, we demonstrated that in addition to reducing scar formation, FMOD also promotes angiogenesis. As blood vessels organize and regulate wound healing, its potent angiogenic properties will further expand the clinical application of FMOD for cutaneous healing of poorly vascularized wounds.

Inhibition of tumor angiogenesis by interferon-γ by suppression of tumor-associated macrophage differentiation

Tumor-associated macrophages (TAMs) differentiate from monocytes and are the M2-polarized macrophages in most human tumors, secreting generous vascular endothelial growth factor (VEGF) to promote angiogenesis. Although it has been shown in vitro that interferon-γ (IFN-γ) can inhibit monocytes differentiating to M2 macrophages in the tumor microenvironment and switch TAMs from M2 into M1, suppressing the ability of secreting VEGF, its effects on TAMs in vivo remains unknown. Here we tried to examine the effects of IFN-γ on the recruitment of monocyte/macrophage differentiation of TAMs and tumor angiogenesis in vivo. We built a gallbladder cancer model by inoculating subcutaneously the human gallbladder cancer cell line (GBC-SD) into BALB/C nude mice and injected the recombinant mouse IFN-γ intratumorally. We found that in the IFN-γ group, the number of monocytes/macrophages was significantly higher than that in the control group (p < 0.01), and TAM differentiation rate, which we defined as the number of TAMs / the number of monocytes/macrophages × 100%, mice-VEGF concentration, and microvessels density (MVD) were significantly lower than those in the control group (p < 0.01, p < 0.05, and p < 0.01). Our results suggest that IFN-γ can induce monocytes/macrophages recruiting into the tumor microenvironment, but inhibit them, differentiating to TAMs in vivo, which may reduce the concentration of VEGF and angiogenesis in tumor.

[Corneal neovascularization: epidemiological, physiopathological, and clinical features]

Corneal neovascularization is defined as the presence of vessels within the normally avascular corneal stroma. This physiopathological process is the consequence of local hyper-expression of pro-angiogenic factors in response to tissue damage. These new vessels (neovessels), initially immature and poorly developed, predispose the cornea to lipid exudation, inflammation, and scarring. Additionally, the influx of vascular cells into the stroma induces a loss of the cornea's immune privilege, resulting in a higher rate of graft rejection. In this literature review, we touch on epidemiological, physiopathological, and clinical aspects of corneal neovascularization, as well as secondary complications.

Transforming growth factor-β regulates the expression of anosmin (KAL-1) in human retinal pigment epithelial cells

In a microarray analysis of human retinal pigment epithelial cells (HRPE) treated with TGF-β, in addition to the alteration of a number of known Extracellular matrix (ECM)-related genes regulated by TGF-β, we found a significant increase in the expression of Kallmann Syndrome (KAL)-1 gene, that codes for the protein anosmin-1. Enhanced expression of KAL-1 by TGF-β was validated by real-time PCR analysis. In in vitro experiments, TGF-β receptor inhibitor abolished TGF-β-induced expression of KAL-1. Immunofluorescence staining showed increased presence of anosmin-1 in TGF-β treated HRPE cells, with distinct localization at the intercellular junctions. Treatment of HRPE cells with TGF-β enhanced secretion of anosmin-1 and the release of anosmin-1 was further augmented by heparin sulfate. Enhanced secretion of anosmin-1 in the presence of TGF-β and heparin was also observed in other ocular cells such as corneal epithelial and corneal fibroblast cultures. The role of anosmin-1, a protein with adhesion functions, in retinal structure, function and pathology has not been known and remains to be investigated.

Adenovirus-mediated delivery of interferon-γ gene inhibits the growth of nasopharyngeal carcinoma

Background

Interferon-γ (IFN-γ) is regarded as a potent antitumor agent, but its clinical application is limited by its short half-life and significant side effects. In this paper, we tried to develop IFN-γ gene therapy by a replication defective adenovirus encoding the human IFN-γ (Ad-IFNγ), and evaluate the antitumoral effects of Ad-IFNγ on nasopharyngeal carcinoma (NPC) cell lines in vitro and in xenografts model.

Methods

The mRNA levels of human IFN-γ in Ad-IFNγ-infected NPC cells were detected by reverse transcription-polymerase chain reaction (RT-PCR), and IFN-γ protein concentrations were measured by enzyme-linked immunosorbent assay (ELISA) in the culture supernatants of NPC cells and tumor tissues and bloods of nude mice treated with Ad-IFNγ. The effects of Ad-IFNγ on NPC cell proliferation was determined using MTT assay, cell cycle distribution was determined by flow cytometry analysis for DNA content, and cells apoptosis were analyzed by Annexin V-FITC/7-AAD binding assay and hoechst 33342/PI double staining. The anti-tumor effects and toxicity of Ad-IFNγ were evaluated in BALB/c nude mice carrying NPC xenografts.

Results

The results demonstrated that Ad-IFNγ efficiently expressed human IFN-γ protein in NPC cell lines in vitro and in vivo. Ad-IFNγ infection resulted in antiproliferative effects on NPC cells by inducing G1 phase arrest and cell apoptosis. Intratumoral administration of Ad-IFNγ significantly inhibited the growth of CNE-2 and C666-1 cell xenografts in nude mice, while no significant toxicity was observed.

Conclusions

These findings indicate IFN-γ gene therapy mediated by replication defective adenoviral vector is likely a promising approach in the treatment of nasopharyngeal carcinoma.

TGF-β1 signaling and Krüppel-like factor 10 regulate bone marrow-derived proangiogenic cell differentiation, function, and neovascularization

Emerging evidence demonstrates that proangiogenic cells (PACs) originate from the BM and are capable of being recruited to sites of ischemic injury where they contribute to neovascularization. We previously determined that among hematopoietic progenitor stem cells, common myeloid progenitors (CMPs) and granulocyte-macrophage progenitor cells (GMPs) differentiate into PACs and possess robust angiogenic activity under ischemic conditions. Herein, we report that a TGF-β1-responsive Krüppel- like factor, KLF10, is strongly expressed in PACs derived from CMPs and GMPs, ∼ 60-fold higher than in progenitors lacking PAC markers. KLF10(-/-) mice present with marked defects in PAC differentiation, function, TGF-β responsiveness, and impaired blood flow recovery after hindlimb ischemia, an effect rescued by wild-type PACs, but not KLF10(-/-) PACs. Overexpression studies revealed that KLF10 could rescue PAC formation from TGF-β1(+/-) CMPs and GMPs. Mechanistically, KLF10 targets the VEGFR2 promoter in PACs which may underlie the observed effects. These findings may be clinically relevant because KLF10 expression was also found to be significantly reduced in PACs from patients with peripheral artery disease. Collectively, these observations identify TGF-β1 signaling and KLF10 as key regulators of functional PACs derived from CMPs and GMPs and may provide a therapeutic target during cardiovascular ischemic states.

Suppressive effect of juzentaihoto on vascularization induced by b16 melanoma cells in vitro and in vivo

Juzentaihoto (JTT) is well known to be one of Japanese herbal medicines, and used for the supplemental therapy of cancer patients with remarkable success. The present study, therefore, was undertaken to examine the possible therapeutic mechanisms of JTT on cancer using B16 melanoma cell (B16 cell)/experimental mouse system. JTT was well mixed with rodent chow at 3.0% concentrations, and was administered orally ad libitum. Administration of JTT was started one week before tumor cell injection and continued throughout the experiment. Administration of JTT into mice significantly inhibited tumor metastasis in lungs after intravenous injection of 2 × 10⁵ B16 cells in a volume of 50 μL. JTT also significantly suppressed enlargement of tumor size in hind footpad after the subcutaneous injection of 2 × 10⁵ (50 μL) B16 cells. In the second part of experiments, the chamber that containing B16 cells was buried in the murine back. In JTT administrated group, vascular endothelial growth factor (VEGF) of chamber internal fluid significantly decreased, and vascularization of chamber circumference was also inhibited. These results strongly suggest that oral administration of JTT caused decrease in the generation of VEGF, which is responsible for vascularization, and results in inhibition of B16 cell metastasis.

Absence of IFN-γ accelerates thrombus resolution through enhanced MMP-9 and VEGF expression in mice

Deep vein thrombosis (DVT) is a major cause of pulmonary thromboembolism, a leading cause of death in individuals with DVT. Several lines of evidence indicate proinflammatory cytokines such as TNF-α are involved in thrombus formation and resolution, but the roles of IFN-γ remain unclear. To address this issue, we performed ligation of the inferior vena cava to induce DVT in WT and IFN-γ-deficient (Ifng-/-) mice. In WT mice, intrathrombotic IFN-γ levels were elevated progressively as the postligation interval was extended. Thrombus size was substantially smaller at 10 and 14 days in Ifng-/- mice than in WT mice. Intrathrombotic collagen content was remarkably reduced at more than 10 days after the ligation in Ifng-/- mice compared with WT mice. The expression and activity of MMP-9, but not MMP-2, was higher at the late phase in Ifng-/- mice than in WT mice. Moreover, intrathrombotic recanalization was increased in Ifng-/- mice, with enhanced Vegf gene expression, compared with that in WT mice. Activation of the IFN-γ/Stat1 signal pathway suppressed PMA-induced Mmp9 and Vegf gene expression in peritoneal macrophages. Furthermore, administration of anti-IFN-γ mAbs accelerated thrombus resolution in WT mice. Collectively, these findings indicate that IFN-γ can have detrimental roles in thrombus resolution and may be a good molecular target for the acceleration of thrombus resolution in individuals with DVT.

Differential cytokine responses in human and mouse lymphatic endothelial cells to cytokines in vitro

BACKGROUND

Inflammatory cytokines dysregulate microvascular function, yet how cytokines affect lymphatic endothelial cells (LEC) are unclear.

METHODS AND RESULTS

We examined effects of TNF-α, IL-1 beta, and IFN-gamma on LEC proliferation, endothelial cell adhesion molecule (ECAM) expression, capillary formation, and barrier changes in murine (SV-LEC) and human LECs (HMEC-1a).

RESULTS

All cytokines induced ICAM-1, VCAM-1, MAdCAM-1, and E-selectin in SV-LECs; TNF-α, IL-1 beta; and IFN-gamma induced ECAMs (but not MAdCAM-1) in HMEC-1a. IL-1 beta increased, while IFN-gamma and TNF-α reduced SV-LEC proliferation. While TNF-α induced, IFN-gamma decreased, and IL-1 beta did not show any effect on HMEC-1a proliferation. TNF-α, IL-1 beta, and IFN-gamma each reduced capillary formation in SV-LEC and in HMEC-1a. TNF-α and IL-1 beta reduced barrier in SV-LEC and HMEC-1a; IFN-gamma did not affect SV-LEC barrier, but enhanced HMEC-1a barrier. Inflammatory cytokines alter LEC growth, activation and barrier function in vitro and may disturb lymphatic clearance increasing tissue edema in vivo.

CONCLUSION

Therapies that maintain or restore lymphatic function (including cytokines blockade), may represent important strategies for limiting inflammation.

The detrimental effects of IFN-α on vasculogenesis in lupus are mediated by repression of IL-1 pathways: potential role in atherogenesis and renal vascular rarefaction

Systemic lupus erythematosus (SLE) is characterized by increased vascular risk due to premature atherosclerosis independent of traditional risk factors. We previously proposed that IFN-α plays a crucial role in premature vascular damage in SLE. IFN-α alters the balance between endothelial cell apoptosis and vascular repair mediated by endothelial progenitor cells (EPCs) and myeloid circulating angiogenic cells (CACs). In this study, we demonstrate that IFN-α promotes an antiangiogenic signature in SLE and control EPCs/CACs, characterized by transcriptional repression of IL-1α and β, IL-1R1, and vascular endothelial growth factor A, and upregulation of IL-1R antagonist and the decoy receptor IL-1R2. IL-1β promotes significant improvement in the functional capacity of lupus EPCs/CACs, therefore abrogating the deleterious effects of IFN-α. The beneficial effects from IL-1 are mediated, at least in part, by increases in EPC/CAC proliferation, by decreases in EPC/CAC apoptosis, and by preventing the skewing of CACs toward nonangiogenic pathways. IFN-α induces STAT2 and 6 phosphorylation in EPCs/CACs, and JAK inhibition abrogates the transcriptional antiangiogenic changes induced by IFN-α in these cells. Immunohistochemistry of renal biopsies from patients with lupus nephritis, but not anti-neutrophil cytoplasmic Ab-positive vasculitis, showed this pathway to be operational in vivo, with increased IL-1R antagonist, downregulation of vascular endothelial growth factor A, and glomerular and blood vessel decreased capillary density, compared with controls. Our study introduces a novel putative pathway by which type I IFNs may interfere with vascular repair in SLE through repression of IL-1-dependent pathways. This could promote atherosclerosis and loss of renal function in this disease.

Pro-angiogenic effect of IFNgamma is dependent on the PI3K/mTOR/translational pathway in human retinal pigmented epithelial cells

PURPOSE

To investigate the molecular signaling pathway of Interferon gamma (IFNgamma) contributing to angiogenesis in retinal pigmented epithelial (RPE) cells and the role of Phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) in this process.

METHODS

Human adult and fetal RPE cells were used in this study. Real-time polymerase chain reaction was used to detect human vascular endothelial growth factor (VEGF) mRNA expression. Thiazolyl blue tetrazolium bromide (MTT) assay was used to detect cell viability. VEGF expression from cell supernatant was measured using enzyme-linked immunosorbent assay (ELISA). Small interfering RNA (SiRNA) of signal transducers and activators of transcription 1 (stat1) and protein kinases B (akt) were transfected into ARPE-19 cells to directly study the roles of these molecules in VEGF expression. Sodium dodecyl sulfate PAGE (SDS-PAGE) and western blot analysis were used to detect the expression of signaling molecules.

RESULTS

IFNgamma promoted human VEGF expression in both adult and fetal RPE cells. The PI-3K/Akt/mTOR/p70 S6 kinase pathway is required for IFNgamma-induced VEGF expression in retinal cells. The mTOR inhibitor, rapamycin, along with the SiRNA targeted to akt and the PI3K inhibitor, LY294002, decreased hVEGF secretion from RPE cells. Moreover, IFNgamma-induced hVEGF expression was not affected by SiRNA targeted to Stat1, implying that the classic Jak-Stat1 pathway of IFNgamma may not be involved in this process.

CONCLUSIONS

We provide evidence that IFNgamma induces VEGF expression in human retinal pigment epithelial cells. Our work emphasizes that the activation of the PI-3K/mTOR/translational pathway is important for IFNgamma-mediated VEGF expression in RPE cells. By elucidating molecular signaling involved in this process, our findings provide further mechanistic insight into the successful clinical application of rapamycin therapy for choroidal neovascularization in age-related macular degeneration (AMD) and uveitis.

Pro-angiogenic effect of IFNgamma is dependent on the PI3K/mTOR/translational pathway in human retinal pigmented epithelial cells

Background

Mutations in COL8A2 gene which encodes the collagen alpha-2 (VIII) chain have been identified in both familial and sporadic cases of Fuchs endothelial corneal dystrophy (FECD). Heterozygous mutations in the SLC4A11 gene are also known to cause late-onset FECD. Therefore we screened for COL8A2, SLC4A11 gene variants in Indian FECD patients.

Methods

Eighty patients with clinically diagnosed FECD and 100 age matched normal individuals were recruited. Genomic DNA was isolated from peripheral blood leukocytes. Mutations in COL8A2, SLC4A11 coding regions were screened using bi-directional sequencing. Fischer's exact test or Pearson's chi squared test were used to predict the statistical association of genotypes with the phenotype.

Results

Screening of COL8A2 gene revealed 2 novel c.1610G>A, c.1643A>G and 3 reported variations c.112G>A, c.464G>A and c.1485G>A. In SLC4A11 gene, novel c.1659C>T, c.1974C>T and reported c.405G>A, c.481A>C and c.639G>A variants were identified. However all the variations in both the genes were also present in unaffected controls.

Conclusions

This is the first study analysing COL8A2 gene in Indian patients with FECD. No pathogenic mutations were identified in COL8A2. Merely silent changes, which showed statistically insignificant association with FECD, were identified in the screening of SLC4A11 gene. These results suggest that COL8A2, SLC4A11 genes may not be responsible for FECD in patients examined in this study.

Novel aspects of corneal angiogenic and lymphangiogenic privilege

In this article, we provide the results of experimental studies demonstrating that corneal avascularity is an active process involving the production of anti-angiogenic factors, which counterbalance the pro-angiogenic/lymphangiogenic factors that are upregulated during wound healing. We also summarize pertinent published reports regarding corneal neovascularization (NV), corneal lymphangiogenesis and corneal angiogenic/lymphangiogenic privilege. We outline the clinical causes of corneal NV, and discuss the angiogenic proteins (VEGF and bFGF) and angiogenesis regulatory proteins. We also describe the role of matrix metalloproteinases MMP-2, -7, and MT1-MMP, anti-angiogenic factors, and lymphangiogenic regulatory proteins during corneal wound healing. Established and potential new therapies for the treatment of corneal neovascularization are also discussed.

IL-11 expression in retinal and corneal cells is regulated by interferon-gamma

Interleukin-11 (IL-11) is an anti-apoptotic, anti-inflammatory cytokine with hematopoietic potential. The expression and protective actions of IL-11 have not been explored in the eye. The expression of IL-11 in primary cultures of human retinal pigment epithelial (HRPE) and human corneal fibroblast (HCRF) cells were evaluated in these studies. Constitutive secretion of IL-11 was not observed in either HRPE or HCRF. TNF-alpha+IL-1 induced IL-11 secretion and this production was inhibited by NFkappaB pathway inhibitors. IFN-gamma significantly inhibited TNF-alpha and IL-1 induced IL-11 secretion and inhibitors of JAK-STAT pathway reversed this inhibition. TGF-beta induced IL-11 secretion that was blocked by TGF-beta receptor 1 inhibitor but not by IFN-gamma. RT-PCR analysis confirmed the effects of IL-1, TNF-alpha, IFN-gamma and TGF-beta on IL-11 secretion at mRNA levels. Our results demonstrate that IL-11 is dramatically up regulated in retina and cornea cells and that IFN-gamma is a physiological inhibitor of IL-11 expression.

Vascular endothelial growth factor receptor-1 (VEGFR-1) expression in human corneal fibroblast decreased with age

PURPOSE

Mechanisms by which fibroblast networks between stromal lamellae are laid in the corneal stroma are far from clear. We have investigated the role of vascular endothelial growth factor receptors (VEGFRs) by in vitro studies in the human corneal network formation obtained from donors whose ages ranged from 19 to 89 years.

METHODS

Corneal fibroblasts were prepared from cornea donations. The functional properties of these cells to form networks were analyzed using a semi solid matrix (substratum) of Matrigel. The presence of VEGF receptor-1 (VEGFR-1) and the functionality in these fibroblasts were investigated using immunofluorescence, molecular analysis (gene microarray, reverse transcription polymerase chain reaction [RT-PCR] and VEGFR siRNA transfections), and cell culture.

RESULTS

Corneal fibroblasts from 61 donors were classified into two groups according to whether they formed (82%) a reticulum on Matrigel or not (18%). By RT-PCR and immunofluorescence analysis, we showed that corneal fibroblasts expressed VEGFR-1 (mRNA and protein). Further, cell culture analysis revealed that only the network (reticulum) forming corneal fibroblast expressed VEGFR-1 in contrast to non network-forming fibroblasts. Use of inhibitors such as VEGFR-1 siRNA transfection or neutralizing antibody (Avastin) indicated that VEGFR-1 was essential to the formation of the corneal network in vitro.

CONCLUSIONS

The cell reticulum formation seemed to be directly related to the expression of VEGFR-1 in the corneal fibroblast, and this expression decreased with age. The decrease in VEGFR-1 expression is probably related to the diminution of autocrine functions, which may alter the overall tissular homeostasis. This may culminate in the gradual development of poor vision, which is observed in certain pathologies and in aging individuals.

Inhibition of vascular endothelial growth factor reduces angiogenesis and modulates immune cell infiltration of orthotopic breast cancer xenografts

Vascular endothelial growth factor (VEGF) is a primary stimulant of angiogenesis and is a macrophage chemotactic protein. Inhibition of VEGF is beneficial in combination with chemotherapy for some breast cancer patients. However, the mechanism by which inhibition of VEGF affects tumor growth seems to involve more than its effect on endothelial cells. In general, increased immune cell infiltration into breast tumors confers a worse prognosis. We have shown previously that 2C3, a mouse monoclonal antibody that prevents VEGF from binding to VEGF receptor 2 (VEGFR2), decreases tumor growth, angiogenesis, and macrophage infiltration into pancreatic tumors and therefore hypothesized that r84, a fully human IgG that phenocopies 2C3, would similarly affect breast tumor growth and immune cell infiltration. In this study, we show that anti-VEGF therapy with bevacizumab, 2C3, or r84 inhibits the growth of established orthotopic MDA-MB-231 breast tumors in severe combined immunodeficiency (SCID) mice, reduces tumor microvessel density, limits the infiltration of tumor-associated macrophages, but is associated with elevated numbers of tumor-associated neutrophils. In addition, we found that treatment with r84 reduced the number of CD11b(+)Gr1(+) double-positive cells in the tumor compared with tumors from control-treated animals. These results show that selective inhibition of VEGFR2 with an anti-VEGF antibody is sufficient for effective blockade of the protumorigenic activity of VEGF in breast cancer xenografts. These findings further define the complex molecular interactions in the tumor microenvironment and provide a translational tool that may be relevant to the treatment of breast cancer.

Corneal transparency: genesis, maintenance and dysfunction

Optimal vision is contingent upon transparency of the cornea. Corneal neovascularization, trauma and, surgical procedures such as photorefractive keratectomy and graft rejection after penetrating keratoplasty can lead to corneal opacification. In this article we identify the underlying basis of corneal transparency and factors that compromise the integrity of the cornea. With evidence from work on animal models and clinical studies, we explore the molecular mechanisms of both corneal avascularity and its dysfunction. We also seek to review therapeutic regimens that can safely salvage and restore corneal transparency.