CXCL10 suppression of hem- and lymph-angiogenesis in inflamed corneas through MMP13

New targets of nascent lymphatic vessels in ocular diseases

Recent advancements in the field of endothelial markers of lymphatic vessels and lymphangiogenic factors have shed light on the association between several ocular diseases and ocular nascent lymphatic vessels. The immune privilege of corneal tissue typically limits the formation of lymphatic vessels in a healthy eye. However, vessels in the eyes can potentially undergo lymphangiogenesis and be conditionally activated. It is evident that nascent lymphatic vessels in the eyes contribute to various ocular pathologies. Conversely, lymphatic vessels are present in the corneal limbus, ciliary body, lacrimal glands, optic nerve sheaths, and extraocular muscles, while a lymphatic vasculature-like system exists in the choroid, that can potentially cause several ocular pathologies. Moreover, numerous studies indicate that many ocular diseases can influence or activate nascent lymphatic vessels, ultimately affecting patient prognosis. By understanding the mechanisms underlying the onset, development, and regression of ocular nascent lymphatic vessels, as well as exploring related research on ocular diseases, this article aims to offer novel perspectives for the treatment of such conditions.

Carbon Ions Suppress Angiogenesis and Lung Metastases in Melanoma by Targeting CXCL10

Carbon-ion radiotherapy (CIRT) enhanced local control in patients with malignant melanoma. In several in vitro studies, carbon ions (C ions) have been also shown to decrease the metastatic potential of melanoma cells. CXC motif 10 (CXCL10) has been shown to play a crucial role in regulating tumor metastasis and it significantly increase in human embryonic kidney cells after heavy ion irradiations. This study sought to explore the regulatory effect of C ions on melanoma metastasis, emphasizing the role of CXCL10 in this process. To explore the potential regulatory effect of C ions on tumor metastasis in vivo, we developed a lung metastasis mouse model by injecting B16F10 cells into the footpad and subjected all mice to treatment with X rays and C ions. Subsequently, a series of assays, including histopathological analysis, enzyme-linked immunosorbent assay, real-time PCR, and western blotting, were conducted to assess the regulatory effects of C ions on melanoma. Our results showed that mice treated with C ions exhibited significantly less tumor vascularity, enhanced tumor necrosis, alleviated lung metastasis, and experienced longer survival than X-ray irradiated mice. Moreover, VEGF expression in B16F10 cells was significantly reduced by C-ion treatment, which could be alleviated by CXCL10 knockdown in vitro. Further investigations revealed that co-culturing with HUVECs resulted in a significant inhibition of proliferation, migration, and tube formation ability in the C-ion treated group, while the opposite effect was observed in the C-ion treated with si-CXCL10 group. In conclusion, our findings demonstrate that treatment with carbon-ion radiation can suppress angiogenesis and lung metastases in melanoma by specifically targeting CXCL10. These results suggest the potential utility of carbon ions in treating melanoma.

Assessing the effects of aging on the renal endothelial cell landscape using single-cell RNA sequencing

Endothelial cells (ECs) with senescence-associated secretory phenotypes (SASP) have been identified as a key mechanism of aging that contributes to various age-related kidney diseases. In this study, we used single-cell RNA sequencing (scRNA-seq) to create a transcriptome atlas of murine renal ECs and identify transcriptomic changes that occur during aging. We identified seven different subtypes of renal ECs, with glomerular ECs and angiogenic ECs being the most affected by senescence. We confirmed our scRNA-seq findings by using double immunostaining for an EC marker (CD31) and markers of specialized EC phenotypes. Our analysis of the dynamics of capillary lineage development revealed a chronic state of inflammation and compromised glomerular function as prominent aging features. Additionally, we observed an elevated pro-inflammatory and pro-coagulant microenvironment in aged glomerular ECs, which may contribute to age-related glomerulosclerosis and renal fibrosis. Through intercellular communication analysis, we also identified changes in signaling involved in immune regulation that may contribute to a hostile microenvironment for renal homeostasis and function. Overall, our findings provide new insights into the mechanisms of aging in the renal endothelium and may pave the way for the discovery of diagnostic biomarkers and therapeutic interventions against age-related kidney diseases.

Altered cytokine levels in the cerebrospinal fluid of adult patients with autism spectrum disorder

BACKGROUND

Despite intensive research, the etiological causes of autism spectrum disorder (ASD) remain elusive. Immunological mechanisms have recently been studied more frequently in the context of maternal autoantibodies and infections, as well as altered cytokine profiles. For the detection of immunological processes in the central nervous system, analyses of cerebrospinal fluid (CSF) are advantageous due to its proximity to the brain. However, cytokine studies in the CSF of ASD patients are sparse.

METHODS

CSF was collected from a patient sample of 24 adults (m = 16, f = 8, age: 30.3 ± 11.6 years) with ASD and compared to a previously published mentally healthy control sample of 39 neurological patients with idiopathic intracranial hypertension. A magnetic bead multiplexing immunoassay was used to measure multiple cytokines in CSF.

RESULTS

Significantly decreased interferon-γ-induced protein-10 (p = 0.001) and monocyte chemoattractant protein-1 (p = 0.041) levels as well as significantly higher interleukin-8 levels (p = 0.041) were detected in patients with ASD compared with the control group.

CONCLUSION

The main finding of this study is an altered cytokine profile in adult patients with ASD compared to the control group. This may indicate immune dysregulation in a subgroup of adult ASD patients. Further studies in larger cohorts that examine a broader spectrum of chemokines and cytokines in general are needed to detect possible specific immune signatures in ASD.

Lymphangiogenesis Guidance Mechanisms and Therapeutic Implications in Pathological States of the Cornea

Corneal lymphangiogenesis is one component of the neovascularization observed in several inflammatory pathologies of the cornea including dry eye disease and corneal graft rejection. Following injury, corneal (lymph)angiogenic privilege is impaired, allowing ingrowth of blood and lymphatic vessels into the previously avascular cornea. While the mechanisms underlying pathological corneal hemangiogenesis have been well described, knowledge of the lymphangiogenesis guidance mechanisms in the cornea is relatively scarce. Various signaling pathways are involved in lymphangiogenesis guidance in general, each influencing one or multiple stages of lymphatic vessel development. Most endogenous factors that guide corneal lymphatic vessel growth or regression act via the vascular endothelial growth factor C signaling pathway, a central regulator of lymphangiogenesis. Several exogenous factors have recently been repurposed and shown to regulate corneal lymphangiogenesis, uncovering unique signaling pathways not previously known to influence lymphatic vessel guidance. A strong understanding of the relevant lymphangiogenesis guidance mechanisms can facilitate the development of targeted anti-lymphangiogenic therapeutics for corneal pathologies. In this review, we examine the current knowledge of lymphatic guidance cues, their regulation of inflammatory states in the cornea, and recently discovered anti-lymphangiogenic therapeutic modalities.

Case report: JAK inhibition as promising treatment option of fatal RVCLS due to TREX1 mutation (pVAL235Glyfs*6)

Introduction

Autosomal dominant mutations in the C-terminal part of TREX1 (pVAL235Glyfs^*6) result in fatal retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCLS) without any treatment options. Here, we report on a treatment of a RVCLS patient with anti-retroviral drugs and the janus kinase (JAK) inhibitor ruxolitinib.

Methods

We collected clinical data of an extended family with RVCLS (TREX1 pVAL235Glyfs^*6). Within this family we identified a 45-year-old woman as index patient that we treated experimentally for 5 years and prospectively collected clinical, laboratory and imaging data.

Results

We report clinical details from 29 family members with 17 of them showing RVCLS symptoms. Treatment of the index patient with ruxolitinib for >4 years was well-tolerated and clinically stabilized RVCLS activity. Moreover, we noticed normalization of initially elevated CXCL10 mRNA in peripheral blood monocular cells (PBMCs) and a reduction of antinuclear autoantibodies.

Discussion

We provide evidence that JAK inhibition as RVCLS treatment appears safe and could slow clinical worsening in symptomatic adults. These results encourage further use of JAK inhibitors in affected individuals together with monitoring of CXCL10 transcripts in PBMCs as useful biomarker of disease activity.

CXCR3 deletion aggravates corneal neovascularization in a corneal alkali-burn model

Corneal neovascularization can cause devastating consequences including vision impairment and even blindness. Corneal inflammation is a crucial factor for the induction of corneal neovascularization. Current anti-inflammatory approaches are of limited value with poor therapeutic effects. Therefore, there is an urgent need to develop new therapies that specifically modulate inflammatory pathways and inhibit neovascularization in the cornea. The interaction of chemokines and their receptors plays a key role in regulating leukocyte migration during inflammatory response. CXCR3 is essential for mediating the recruitment of activated T cells and microglia/macrophages, but the role of CXCR3 in the initiation and promotion of corneal neovascularization remains unclear. Here, we showed that the expression of CXCL10 and CXCR3 was significantly increased in the cornea after alkali burn. Compared with WT mice, CXCR3-/- mice exhibited significantly increased corneal hemangiogenesis and lymphangiogenesis after alkali burn. In addition, exaggerated leukocyte infiltration and leukostasis, and elevated expression of inflammatory cytokines and angiogenic factor were also found in the corneas of CXCR3-/- mice subjected to alkali burn. With bone marrow (BM) transplantation, we further demonstrated that the deletion of CXCR3 in BM-derived leukocytes plays a key role in the acceleration of alkali burn-induced corneal neovascularization. Taken together, our results suggest that upregulation of CXCR3 does not exhibit its conventional action as a proinflammatory cytokine but instead serves as a self-protective mechanism for the modulation of inflammation and maintenance of corneal avascularity after corneal alkali burn.

The Peripheral Lymphatic System Is Impaired by the Loss of Neuronal Control Associated with Chronic Spinal Cord Injury

Spinal cord injury (SCI) is associated with venous vascular dysfunction below the level of injury, resulting in dysregulation of tissue fluid homeostasis in afflicted skin. The purpose of this study was to determine whether loss of neuronal control in chronic SCI also affects the skin lymphatic system. Morphology of lymphatics was characterized by immunohistochemistry and lymphatic gene expression profiles determined by DNA microarray analysis. In SCI, skin lymphatic function appeared to be impaired, because the ratio of functionally dilated versus collapsed lymphatic vessels was decreased 10-fold compared with control. Consequently, the average lumen area of lymphatic vessels was almost halved, possibly due to the known impaired connective tissue integrity of SCI skin. In fact, collagenases were found to be overexpressed in SCI skin, and dermal collagen structure was impaired. Molecular profiling also suggested an SCI-specific phenotype of increased connective tissue turnover and decreased lymphatic contractility. The total number of lymphatic vessels in SCI skin, however, was doubled, pointing to enhanced lymphangiogenesis. In conclusion, these data show, for the first time, that lymphatic function and development in human skin are under neuronal control. Because peripheral venous and lymphatic vascular defects are associated with disturbed fluid homeostasis, inappropriate wound healing reactions, and impaired skin immunity, they might contribute to the predisposition of afflicted individuals to pressure ulcer formation and wound healing disorders.

The Role of Geranylgeraniol in Managing Bisphosphonate-Related Osteonecrosis of the Jaw

Medication-related osteonecrosis of the jaw (ONJ) is a rare but significant adverse side effect of antiresorptive drugs. Bisphosphonate-related ONJ (BRONJ) is the most prevalent condition due to the extensive use of the drug in cancer and osteoporosis treatment. Nitrogen-containing bisphosphonates suppress osteoclastic resorption by inhibiting farnesyl pyrophosphate synthase in the mevalonate pathway, leading to deficiency of the substrate for GTPase prenylation. The bone remodelling process is uncoupled, subsequently impairing bone healing and causing ONJ. Targeted administration of geranylgeraniol (GGOH) represents a promising approach to mitigate BRONJ because GGOH is a substrate for GTPase prenylation. In the current review, the in vitro effects of GGOH on osteoclasts, osteoblasts and other related cells of the jaw are summarised. We also present and appraise the current in vivo evidence of GGOH in managing BRONJ in animal models. Lastly, several considerations of using GGOH in the clinical management of BRONJ are highlighted. As a conclusion, GGOH is a promising topical agent to manage BRONJ, pending more research on an effective delivery system and validation from a clinical trial.

PABPC1-induced stabilization of IFI27 mRNA promotes angiogenesis and malignant progression in esophageal squamous cell carcinoma through exosomal miRNA-21-5p

BACKGROUND

Emerging evidence has demonstrated that RNA-binding protein dysregulation is involved in esophageal squamous cell carcinoma (ESCC) progression. However, the role of poly (A) binding protein cytoplasmic 1 (PABPC1) in ESCC is unclear. We therefore aimed to explore the functions and potential mechanisms of PABPC1 in ESCC progression.

METHODS

PABPC1 expression was characterized using immunohistochemistry and qRT-PCR in ESCC tissues and cell lines. Chromatin immunoprecipitation (ChIP) and luciferase reporter assays were used to detect histone acetylation in the promoter region of PABPC1. A series of in vitro and in vivo assays were further applied to elucidate the functions and underlying molecular mechanisms of PABPC1 in ESCC angiogenesis and malignant procession.

RESULTS

PABPC1 expression was upregulated in ESCC tissues compared with in normal esophageal epithelial tissues. Elevated PABPC1 expression was correlated with tumor cell differentiation and poor prognosis in patients. Sp1 and p300 cooperated to increase the level of H2K37ac in the PABPC1 promoter. Functionally, PABPC1 overexpression enhanced esophageal squamous cell proliferation and invasion by activating the IFN/IFI27 signaling pathway. PABPC1 interacted with eIF4G to increase the stability of IFI27 mRNA by competing with RNA exosomes in ESCC. Furthermore, PABPC1/IFI27 could increase miR-21-5p expression to enable exosomal delivery of miR-21-5p to human umbilical vein endothelial cells to increase angiogenesis via inhibiting CXCL10.

CONCLUSION

PABPC1 plays a critical role in ESCC malignant progression by interacting with eIF4G to regulate IFI27 mRNA stability and promote angiogenesis via exosomal miR-21-5p/CXCL10. Taken together, our results suggest that PABPC1 is a promising therapeutic target for ESCC.

Role of CXCL10 in Spinal Cord Injury

Spinal cord injury (SCI) results in acute inflammatory responses and secondary damages, including neuronal and glial cell death, axonal damage and demyelination, and blood-brain barrier (BBB) damage, eventually leading to neuronal dysfunction and other complications. C-X-C motif Chemokine Ligand 10 (CXCL10) is expressed after the injury, playing multiple roles in the development and progression of SCI. Moreover, the CXCL10 antagonist can restrict inflammatory immune responses and promote neuronal regeneration and functional recovery. In this review, we summarize the structure and biological functions of CXCL10, and the roles of the CXCL10 / CXCR3 axis in acute inflammatory responses, secondary damages, and complications during SCI, thus providing a potential theoretical basis by highlighting CXCL10 as a new potential drug target for the treatment of SCI.

Role of IL-36γ/IL-36R Signaling in Corneal Innate Defense Against Candida albicans Keratitis

Purpose

Interleukin (IL)-36 cytokines have been shown to play either beneficial or detrimental roles in the infection of mucosal tissues in a pathogen-dependent manner, but their involvement in fungal keratitis remains elusive. We herein investigated their expression and function in mediating corneal innate immunity against Candida albicans infection.

Methods

Gene expression in mouse corneas with or without C. albicans infection was determined by regular RT- and real-time (q)-PCR, Western blot analysis, ELISA or proteome profile assay. The severity of C. albicans keratitis was assessed using clinical scoring, bacterial counting, and myeloperoxidase (MPO) activity as an indicator of neutrophil infiltration. IL36R knockout mice and IL-33-specific siRNA were used to assess the involvement IL-33 signaling in C. albicans-infected corneas. B6 CD11c-DTR mice and clodronate liposomes were used to define the involvement of dendritic cells (DCs) and macrophages in IL-36R signaling and C. albicans keratitis, respectively.

Results

IL-36γ were up-regulated in C57BL6 mouse corneas in response to C. albicans infection. IL-36 receptor-deficient mice display increased severity of keratitis, with a higher fungal load, MPO, and IL-1β levels, and lower soluble sIL-1Ra and calprotectin levels. Exogenous IL-36γ prevented fungal keratitis pathogenesis with lower fungal load and MPO activity, higher expression of sIL-1Ra and calprotectin, and lower expression of IL-1β, at mRNA or protein levels. Protein array analysis revealed that the expression of IL-33 and REG3G were related to IL-36/IL36R signaling, and siRNA downregulation of IL-33 increased the severity of C. albicans keratitis. Depletion of dendritic cells or macrophages resulted in severe C. albicans keratitis and yet exhibited minimal effects on exogenous IL-36γ-induced protection against C. albicans infection in B6 mouse corneas.

Conclusions

IL-36/IL36R signaling plays a protective role in fungal keratitis by promoting AMP expression and by suppressing fungal infection-induced expression of proinflammatory cytokines in a dendritic cell- and macrophage-independent manner.

CNTF Prevents Development of Outer Retinal Neovascularization Through Upregulation of CxCl10

Purpose

Ciliary neurotrophic factor (CNTF) is a well-characterized neurotrophic factor currently in clinical trials for the treatment of macular telangiectasia type II. Our previous work showed that CNTF-induced STAT3 signaling is a potent inhibitor of pathologic preretinal neovascular tuft formation in the mouse model of oxygen-induced retinopathy. In this study, we investigated the effect of CNTF on outer retinal and choroidal angiogenesis and the mechanisms that underpin the observed decrease in outer retinal neovascularization following CNTF treatment.

Methods

In the Vldlr^–/– and laser-CNV mouse models, mice received a one-time injection (on postnatal day [P] 12 in the Vldlr^–/– model and 1 day after laser in the Choroidal Neovascularization (CNV) model) of recombinant CNTF or CxCl10, and the extent of neovascular lesions was assessed 6 days posttreatment. STAT3 downstream targets affected by CNTF treatment were identified using quantitative PCR analysis. A proteome array was used to compare media conditioned by CNTF-treated and control-treated primary Müller cells to screen for CNTF-induced changes in secreted angiogenic factors.

Results

Intravitreal treatment with recombinant CNTF led to significant reduction in neovascularization in the Vldlr^–/– and laser-CNV mouse models. Treatment effect in the Vldlr^–/– was long-lasting but time sensitive, requiring intravitreal treatment before P19. Mechanistic workup in vitro as well as in vivo confirmed significant activation of the STAT3-signaling pathway in Müller cells in response to CNTF treatment and upregulation of CxCl10. Intravitreal injections of recombinant CxCl10 significantly reduced outer retinal neovascularization in vivo in both the Vldlr^–/– and laser-CNV mouse models.

Conclusions

CNTF treatment indirectly affects outer retinal and choroidal neovascularization by inducing CxCl10 secretion from retinal Müller cells.

Effects of Retinal Transcription Regulation After GB20 Needling Treatment in Retina With Optic Neuritis

Optic neuritis (ON) is one of the most frequent symptoms of multiple sclerosis (MS) that results in progressive loss of axons and neurons. In clinical trials of Traditional Chinese Medicine, needling at the GB20 acupoint has been widely used for the treatment of ocular diseases, including ON. However, the molecular mechanisms of needling at this site are still unclear. In this study, we generated an experimental autoimmune encephalomyelitis (EAE) mouse model and investigated the effects of needling treatment at the GB20 acupoint on retina with EAE-associated ON. RNA sequencing of the retinal transcriptome revealed that, of the 234 differentially expressed genes induced by ON, 100 genes were upregulated, and 134 genes were downregulated by ON, while needling at the GB20 acupoint specifically reversed the expression of 21 genes compared with control treatment at GV16 acupoint. Among the reversed genes, Nr4a3, Sncg, Uchl1, and Tppp3 were involved in axon development and regeneration and were downregulated by ON, indicating the beneficial effect of needling at GB20. Further gene ontology (GO) enrichment analysis revealed that needling at GB20 affected the molecular process of Circadian rhythm in mouse retina with ON. Our study first reported that needling treatment after ON at the GB20 acupoint regulated gene expression of the retina and reversed the expression of downregulated axon development-related genes. This study also demonstrated that GV16 was a perfect control treatment site for GB20 in animal research. Our study provided a scientific basis for needling treatments at GB20 for ocular diseases.

Pharmacological Inhibition of Caspase-8 Suppresses Inflammation-Induced Angiogenesis in the Cornea

Inflammation-induced angiogenesis is closely related to many diseases and has been regarded as a therapeutic target. Caspase-8 has attracted increasing attention for its immune properties and therapeutic potential in inflammatory disorders. The aim of our study is to investigate the clinical application of pharmacological inhibition of caspase-8 and the underlying molecular mechanisms in inflammation-induced angiogenesis in the cornea. A model of alkali burn (AB)-induced corneal neovascularization (CNV) in C57BL/6 wild-type (WT) mice and toll-like receptor 4 knockout (Tlr4^-/-) mice was used. We found that AB increased caspase-8 activity and the pharmacological inhibition of caspase-8 exerted substantial inhibitory effects on CNV, with consistent decreases in caspase-8 activity, inflammatory cell infiltration, macrophage recruitment and activation, VEGF-A, TNF-α, IL-1β, MIP-1, and MCP-1 expression in the cornea. In vitro, caspase-8 mediated TLR4–dependent chemokines and VEGF-A production by macrophages. The TLR4 knockout significantly alleviated CNV, suppressed caspase-8 activity and downregulated expression of inflammatory cytokines and chemokines after AB. Taken together, these findings provide the first demonstration that the pharmacological inhibition of caspase-8 suppresses inflammation-induced angiogenesis and support the use of a pharmacological caspase-8 inhibitor as a novel clinical treatment for CNV and other angiogenic disorders.

Exploring the Key Genes and Pathways in the Formation of Corneal Scar Using Bioinformatics Analysis

The Corneal wound healing results in the formation of opaque corneal scar. In fact, millions of people around the world suffer from corneal scars, leading to loss of vision. This study aimed to identify the key changes of gene expression in the formation of opaque corneal scar and provided potential biomarker candidates for clinical treatment and drug target discovery. We downloaded Gene expression dataset GSE6676 from NCBI-GEO, and analyzed the Differentially Expressed Genes (DEGs), Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway analyses, and protein-protein interaction (PPI) network. A total of 1377 differentially expressed genes were identified and the result of Functional enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) identification and protein-protein interaction (PPI) networks were performed. In total, 7 hub genes IL6 (interleukin-6), MMP9 (matrix metallopeptidase 9), CXCL10 (C-X-C motif chemokine ligand 10), MAPK8 (mitogen-activated protein kinase 8), TLR4 (toll-like receptor 4), HGF (hepatocyte growth factor), EDN1 (endothelin 1) were selected. In conclusion, the DEGS, Hub genes and signal pathways identified in this study can help us understand the molecular mechanism of corneal scar formation and provide candidate targets for the diagnosis and treatment of corneal scar.

Deriving a Boolean dynamics to reveal macrophage activation with in vitro temporal cytokine expression profiles

BACKGROUND

Macrophages show versatile functions in innate immunity, infectious diseases, and progression of cancers and cardiovascular diseases. These versatile functions of macrophages are conducted by different macrophage phenotypes classified as classically activated macrophages and alternatively activated macrophages due to different stimuli in the complex in vivo cytokine environment. Dissecting the regulation of macrophage activations will have a significant impact on disease progression and therapeutic strategy. Mathematical modeling of macrophage activation can improve the understanding of this biological process through quantitative analysis and provide guidance to facilitate future experimental design. However, few results have been reported for a complete model of macrophage activation patterns.

RESULTS

We globally searched and reviewed literature for macrophage activation from PubMed databases and screened the published experimental results. Temporal in vitro macrophage cytokine expression profiles from published results were selected to establish Boolean network models for macrophage activation patterns in response to three different stimuli. A combination of modeling methods including clustering, binarization, linear programming (LP), Boolean function determination, and semi-tensor product was applied to establish Boolean networks to quantify three macrophage activation patterns. The structure of the networks was confirmed based on protein-protein-interaction databases, pathway databases, and published experimental results. Computational predictions of the network evolution were compared against real experimental results to validate the effectiveness of the Boolean network models.

CONCLUSION

Three macrophage activation core evolution maps were established based on the Boolean networks using Matlab. Cytokine signatures of macrophage activation patterns were identified, providing a possible determination of macrophage activations using extracellular cytokine measurements.

Systemic Sclerosis Serum Significantly Impairs the Multi-Step Lymphangiogenic Process: in Vitro Evidence

In systemic sclerosis (SSc), the possible involvement of lymphatic microcirculation and lymphangiogenesis has traditionally been overshadowed by the greater emphasis placed on dysfunctional blood vascular system and angiogenesis. In the present in vitro study, we explore for the first time whether the SSc microenvironment may interfere with lymphangiogenesis, a complex, multi-step process in which lymphatic microvascular endothelial cells (LMVECs) sprout, migrate, and proliferate to generate new lymphatic capillaries. Normal human adult dermal LMVECs from three donors were treated with serum from SSc patients (n = 8), serum from healthy individuals (n = 8), or recombinant human vascular endothelial growth factor (VEGF)-C as a positive control for lymphangiogenesis. Cell proliferation, Boyden chamber Matrigel chemoinvasion, wound healing capacity, and lymphatic capillary morphogenesis on Geltrex were assayed. VEGF-C serum levels were measured by enzyme-linked immunosorbent assay. Gene and protein expression levels of the lymphangiogenic orchestrators VEGF receptor-3 (VEGFR-3)/Flt-4 and neuropilin-2 (NRP-2) were determined by real-time PCR and Western blotting, respectively. Conditioning with SSc serum significantly inhibited LMVEC proliferation, Matrigel invasion, and wound healing capacity with respect to healthy serum. The ability of LMVECs to form lymphatic tubes on Geltrex was also severely compromised in the presence of SSc serum. VEGF-C levels were comparable in SSc and healthy sera. Treatment with SSc serum resulted in a significant downregulation of both VEGFR-3/Flt-4 and NRP-2 mRNA and protein levels. In SSc, the pathologic environment severely hampers every lymphangiogenesis step, likely through the reduction of pro-lymphangiogenic VEGFR-3/NRP-2 co-receptor signaling. The impairment of the lymphangiogenic process opens a new scenario underlying SSc vascular pathophysiology, which is worth investigating further.

Fungal keratitis: Pathogenesis, diagnosis and prevention

As a kind of serious, potentially sight-threatening corneal infections with poor prognosis, fungal keratitis can bring a heavy economic burden to patients and seriously affect the quality of life, especially those in developing countries where fungal keratitis is more prevalent. Typical clinical features include immune rings, satellite lesions, pseudopods, hypha moss, hypopyon and endothelial plaques. The ideal therapeutic effects could not be achieved by current treatments for many reasons. Therefore, under the current status, understanding the pathogenesis, early diagnosis and prevention strategies might be of great importance. Here, in this review, we discuss the recent progresses that may advance our understanding of pathogenesis, early diagnosis and prevention of fungal keratitis.

Increased succinate receptor GPR91 involved in the pathogenesis of Mooren's ulcer

AIM

To investigate the expression of succinate receptor GPR91 and its pathogenic roles in Mooren's ulcer (MU).

METHODS

Biopsy specimens were obtained from 7 patients with MU and 6 healthy donors. The expression of GPR91 in MU tissues was evaluated using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). Succinate was used to activate GPR91 signaling, and the effect of GPR91 on the expression of interleukin-1β (IL-1β), NLRP3, vascular endothelial growth factor (VEGF) and matrix metalloproteinase-13 (MMP-13) in human peripheral blood mononuclear cells (PBMCs) was determined. The influence of GPR91 on the nuclear factor-κB (NF-κB) signaling in PBMCs was investigated by detecting the phosphorylation of p65. Moreover, the expression of IL-1β, VEGF, MMP-13 and phosphorylated p65 (p-p65) in the tissues of MU was examined by qRT-PCR or IHC.

RESULTS

GPR91 mRNA expression showed a higher level in the MU group than in the healthy control group. IHC analysis also revealed that the expression of GPR91 was elevated in patients with MU compared with healthy controls. Moreover, ligation of GPR91 with succinate promoted the lipopolysaccharide-induced production of NLRP3, IL-1β, VEGF and MMP-13 in PBMCs through increased phosphorylation of p65. Pharmacological inhibition of the NF-κB signaling reversed GPR91 induced production of NLRP3, IL-1β, VEGF and MMP-13. These findings, coupled with the elevated amounts of IL-1β, VEGF, MMP-13 and p-p65 observed in the MU biopsies, constituted a rational basis for the involvement of GPR91 in the pathogenesis of MU.

CONCLUSION

This study indicates the increased succinate receptor GPR91 in conjunctival or corneal tissues is involved in the pathogenesis of MU through elevated NF-κB activity, which may provide a new therapeutic target for MU.

Consensus guidelines for the use and interpretation of angiogenesis assays

The formation of new blood vessels, or angiogenesis, is a complex process that plays important roles in growth and development, tissue and organ regeneration, as well as numerous pathological conditions. Angiogenesis undergoes multiple discrete steps that can be individually evaluated and quantified by a large number of bioassays. These independent assessments hold advantages but also have limitations. This article describes in vivo, ex vivo, and in vitro bioassays that are available for the evaluation of angiogenesis and highlights critical aspects that are relevant for their execution and proper interpretation. As such, this collaborative work is the first edition of consensus guidelines on angiogenesis bioassays to serve for current and future reference.

Characterization of multi-cellular dynamics of angiogenesis and vascular remodelling by intravital imaging of the wounded mouse cornea

Establishment of the functional blood vasculature involves extensive cellular rearrangement controlled by growth factors, chemokines and flow-mediated shear forces. To record these highly dynamic processes in mammalians has been technically demanding. Here we apply confocal and wide field time-lapse in vivo microscopy to characterize the remodelling vasculature of the wounded mouse cornea. Using mouse lines with constitutive or inducible endogenous fluorescent reporters, in combination with tracer injections and mosaic genetic recombination, we follow processes of sprouting angiogenesis, sprout fusion, vessel expansion and pruning in vivo, at subcellular resolution. We describe the migratory behaviour of endothelial cells of perfused vessels, in relation to blood flow directionality and vessel identity. Live-imaging following intravascular injection of fluorescent tracers, allowed for recording of VEGFA-induced permeability. Altogether, live-imaging of the remodelling vasculature of inflamed corneas of mice carrying endogenous fluorescent reporters and conditional alleles, constitutes a powerful platform for investigation of cellular behaviour and vessel function.

B-cell leukemia/lymphoma 10 promotes angiogenesis in an experimental corneal neovascularization model

PURPOSE

Corneal neovascularization (CrNV) arises from many causes including corneal inflammatory, infectious, or traumatic insult, and frequently leads to impaired vision. This study seeks to determine the role of B-cell leukemia/lymphoma 10 (BCL-10) in the development of experimental CrNV.

METHODS

Corneas from BCL-10 knockout (KO) mice and wild-type (WT) mice were burned by sodium hydroxide (NaOH) to create the CrNV model and neovascular formation in the corneas was assessed 2 weeks later. Intracorneal macrophage accumulation and the expression of angiogenic factors were quantified by flow cytometric analysis (FCM) and real-time PCR, respectively.

RESULTS

The amount of CrNV was determined 2 weeks after alkali burn. Compared to WT mice, the amount of CrNV in BCL-10 KO mice was significantly decreased. FCM revealed that F4/80-positive macrophages were markedly decreased in BCL-10 KO mice compared with WT mice. Reverse transcription PCR showed that the mRNA expression levels of intracorneal vascular endothelial growth factor-A (VEGF-A), basic fibroblast growth factor (bFGF) and monocyte chemotactic protein 1 were reduced in BCL-10 KO mice compared with WT mice.

CONCLUSION

BCL-10 KO mice exhibited reduced alkali-induced CrNV by suppressing intracorneal macrophage infiltration, which subsequently led to decreased VEGF-A and bFGF expression, suggesting that BCL-10 may become a potential clinical intervening target of CrNV.

Opposing Effects of IL-1Ra and IL-36Ra on Innate Immune Response to Pseudomonas aeruginosa Infection in C57BL/6 Mouse Corneas

Pseudomonas aeruginosa keratitis is characterized by severe corneal ulceration and may lead to blindness if not treated properly in a timely manner. Although the roles of the IL-1 subfamily of cytokines are well established, as a newly discovered subfamily, IL-36 cytokine regulation, immunological relevance, and relation with IL-1 cytokines in host defense remain largely unknown. In this study, we showed that P. aeruginosa infection induces the expression of IL-36α and IL-36γ, as well as IL-1β and secreted IL-1Ra (sIL-1Ra), but not IL-36Ra. Downregulation of IL-1Ra increases, whereas downregulation of IL-36Ra decreases the severity of P. aeruginosa keratitis. IL-1R and IL-36Ra downregulation have opposing effects on the expression of IL-1β, sIL-1Ra, IL-36γ, S100A8, and CXCL10 and on the infiltration of innate immune cells. Administration of recombinant IL-1Ra improved, whereas IL-36Ra worsened the outcome of P. aeruginosa keratitis. Local application of IL-36γ stimulated the expression of innate defense molecules S100A9, mouse β-defensin 3, but suppressed IL-1β expression in B6 mouse corneas. IL-36γ diminished the severity of P. aeruginosa keratitis, and its protective effects were abolished in the presence of S100A9 neutralizing Ab and partially affected by CXCL10 and CXCR3 neutralizations. Thus, our data reveal that IL-1Ra and IL-36Ra have opposing effects on the outcome of P. aeruginosa keratitis and suggest that IL-36 agonists may be used as an alternative therapeutic to IL-1β-neutralizing reagents in controlling microbial keratitis and other mucosal infections.

Overview of the Mechanisms that May Contribute to the Non-Redundant Activities of Interferon-Inducible CXC Chemokine Receptor 3 Ligands

The inflammatory chemokines CXCL9, CXCL10, and CXCL11 are predominantly induced by interferon (IFN)-γ and share an exclusive chemokine receptor named CXC chemokine receptor 3 (CXCR3). With a prototype function of directing temporal and spatial migration of activated T cells and natural killer cells, and inhibitory effects on angiogenesis, these CXCR3 ligands have been implicated in infection, acute inflammation, autoinflammation and autoimmunity, as well as in cancer. Intense former research efforts led to recent and ongoing clinical trials using CXCR3 and CXCR3 ligand targeting molecules. Scientific evidence has claimed mutual redundancy, ligand dominance, collaboration or even antagonism, depending on the (patho)physiological context. Most research on their in vivo activity, however, illustrates that CXCL9, CXCL10, and CXCL11 each contribute to the activation and trafficking of CXCR3 expressing cells in a non-redundant manner. When looking into detail, one can unravel a multistep machinery behind final CXCR3 ligand functions. Not only can specific cell types secrete individual CXCR3 interacting chemokines in response to certain stimuli, but also the receptor and glycosaminoglycan interactions, major associated intracellular pathways and susceptibility to processing by particular enzymes, among others, seem ligand-specific. Here, we overview major aspects of the molecular properties and regulatory mechanisms of IFN-induced CXCR3 ligands, and propose that their in vivo non-redundancy is a reflection of the unprecedented degree of versatility that seems inherent to the IFN-related CXCR3 chemokine system.