Interleukin (IL)-17A Promotes Angiogenesis in an Experimental Corneal Neovascularization Model

Cyclopamine inhibits corneal neovascularization and fibrosis by alleviating inflammatory macrophage recruitment and endothelial cell activation

PURPOSE

To explore the function of cyclopamine in corneal neovascularization and subsequent fibrosis after cornea alkali-burn injury.

METHODS

In vivo, mice cornea were injured by NaOH, and then treated with cyclopamine, clodronate liposomes (CLO-LPS), and vehicle of cyclopamine separately by subconjunctival injections. Clinical features were observed and pathological characteristics were examined. In vitro, M1 macrophages (M1φ) and human umbilical vein endothelial cells (HUVECs) were co-cultured, and the abilities of proliferation, migration, and tube formation of HUVECs were detected under different interventions of M1φ.

RESULTS

Alkali-burn injury induced massive angiogenesis and decreased transparency of the cornea, along with numerous macrophages infiltration and Shh protein expression in the cornea. However, corneal neovascularization, macrophage infiltration, and Shh expression could suppressed by cyclopamine and CLO-LPS significantly. In addition, treatment with cyclopamine also reduced the expression of inflammatory factors (TNF-α, IL-6) and fibrosis factors (VIM, α-SMA). In vitro, M1φ promotes migration and tube formation of HUVECs by secreting Shh protein, which could be inhibited by cyclopamine.

CONCLUSION

Cyclopamine could suppress inflammation and angiogenesis of alkali-burned cornea, as well as subsequent fibrosis. The study reveals that cyclopamine suppresses corneal neovascularization in a dual mechanism of inhibiting macrophage infiltration and suppressing Shh signaling.

Integrating network pharmacology and transcriptomics to study the potential mechanism of Jingzhi Niuhuang Jiedu tablet in rats with accumulation of heat in the lungs and stomach

ETHNOPHARMACOLOGICAL RELEVANCE

Accumulation of heat in the lungs and stomach (AHLS) is an important syndrome within the realm of traditional Chinese medicine (TCM). It is the fundamental reason behind numerous illnesses, including mouth ulcers, dermatological conditions, acne, and pharyngitis. Jingzhi Niuhuang Jiedu tablet (JN) serves as the representative prescription for treatment of AHLS clinically. However, the effective components and mechanism of JN's impact on AHLS remain unexplored.

AIM OF THE STUDY

The objective of this research was to analyze the effective components of JN and investigate the therapeutic effect and potential mechanism of JN on AHLS.

MATERIALS AND METHODS

The effective compounds of JN extract were analyzed and identified using UHPLC-Q-Exactive/HRMS. Utilizing network pharmacology to investigate JN's multi-target, multi-pathway process in treating AHLS. Subsequently, anti-inflammatory activities of JN extract were evaluated in the RAW264.7 cells stimulated by lipopolysaccharide (LPS). In addition, a rat AHLS model induced by LPS and dried ginger was established. Pathological changes in rat lung and stomach tissues observed by HE staining and Masson's trichrome staining. Additionally, the expression of TNF-α, IL-6, and IL-1β in bronchoalveolar lavage fluid (BALF) was identified through the ELISA assay. For a deeper understanding of how JN might affect AHLS, transcriptomics was utilized to examine differential genes and their underlying mechanisms. Concurrently, techniques like quantitative polymerase chain reaction (q-PCR), immunofluorescence, and western blotting (WB) were employed to confirm various mRNA and protein expression, including Il17ra, Il17re, IL-17A, IL-1β, IL-6, PPARγ, PGC1-α and UCP1.

RESULTS

We identified 178 potential effective components in the JN extract. Network pharmacology analysis showed that the 144 components in JN act on 200 key targets for the treatment of AHLS by suppressing inflammation, regulating energy metabolism, and gastric function. In addition, JN suppressed the LPS-stimulated generation of NO, TNF-α, IL-1β, and IL-6 in RAW264.7 cells. And JN treatment effectively alleviated lung and stomach injury and reduced inflammation in rats. Analysis of RNA-seq from lung tissues revealed JN's substantial control over crucial genes in the IL-17 signaling pathway, including Il1b and Il17ra. Likewise, RNA sequencing of stomach tissues revealed that JN markedly decreased crucial genes in the Thermogenesis pathway, including Ppargc1a and Ppara. Additional experimental findings confirmed that treatment with JN significantly reduced the expression levels of mRNA (Il17ra, Il17re, Il1b, Ppargc1a and Ucp1), and the expression levels of protein (IL-17A, IL-1β, IL-6, PPARγ, PGC1-α and UCP1).

CONCLUSION

This study not only analyzes the effective components of JN but also reveals that JN could effectively ameliorate AHLS by inhibiting IL-17 signaling pathway and Thermogenesis pathway, which provides evidence for subsequent clinical studies and drug development.

Inhibition of Experimental Corneal Neovascularization by the Tight Junction Protein ZO-1

Purpose: To explore the effects of the tight junction protein zonula occludens 1 (ZO-1) on experimental corneal neovascularization (CNV). Methods: CNV models were established in the left eyes of BALB/c mice using NaOH. Anti-ZO-1 neutralizing antibody was topically applied to the burnt corneas after modeling thrice a day for 1 week. CD31 expression was analyzed to calculate the ratio of CNV number to area using a corneal whole-mount fluorescent immunohistochemical assay. Messenger ribonucleic acid (mRNA) and protein expression levels of ZO-1, vascular endothelial growth factor (VEGF), interleukin (IL)-1β, IL-6, IL-8, IL-18, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor alpha (TNF-α), phosphorylated protein kinase C (pPKC), and clusterin in burned corneas were detected by reverse transcriptase polymerase chain reaction (PCR) and western blot analyses. Infiltration of neutrophils, macrophages, and progenitor cells was examined by flow cytometry. Results: CNV was obviously greater in 45 s than in 15 s alkali injury group. In another experiment, CNV was obviously greater in the ZO-1 antibody group than in the vehicle-treated group. Corneal mRNA and protein expression levels of VEGF, IL-1β, IL-6, IL-8, IL-18, and MCP-1 were significantly higher in the ZO-1 antibody group than in the control group. Infiltration of neutrophils, macrophages, and progenitor cells was significantly greater in the ZO-1 antibody group than in the control group. TNF-α expression was much higher in 45 s than in 15 s alkali injury group. However, protein expression of pPKC and clusterin was much lower in 45 s than in 15 s alkali injury group. Conclusions: Anti-ZO-1 neutralizing antibody-treated mice exhibited enhanced alkali-induced CNV through enhanced intracorneal infiltration of progenitor and inflammatory cells.

Role of macrophage in ocular neovascularization

Ocular neovascularization is the leading cause of blindness in clinical settings. Pathological angiogenesis of the eye can be divided into corneal neovascularization (CoNV), retinal neovascularization (RNV, including diabetic retinopathy and retinopathy of prematurity), and choroidal neovascularization (CNV) based on the anatomical location of abnormal neovascularization. Although anti-Vascular endothelial growth factor (VEGF) agents have wide-ranging clinical applications and are an effective treatment for neovascular eye disease, many deficiencies in this treatment strategy remain. Recently, emerging evidence has demonstrated that macrophages are vital during the process of physiological and pathological angiogenesis. Monocyte-macrophage lineage is diverse and plastic, they can shift between different activation modes and have different functions. Due to the obvious regulatory effect of macrophages on inflammation and angiogenesis, macrophages have been increasingly studied in the field of ophthalmology. Here, we detail how macrophage activated and the role of different subtypes of macrophages in the pathogenesis of ocular neovascularization. The complexity of macrophages has recently taken center stage owing to their subset diversity and tightly regulated molecular and metabolic phenotypes. In this review, we reveal the functional and phenotypic characterization of macrophage subsets associated with ocular neovascularization, more in-depth research is needed to explore the specific mechanisms by which macrophages regulate angiogenesis as well as macrophage polarization. Targeted regulation of macrophage differentiation based on their phenotype and function could be an effective approach to treat and manage ocular neovascularization in the future.

Upadacitinib inhibits corneal inflammation and neovascularization by suppressing M1 macrophage infiltration in the corneal alkali burn model

Alkali burn-induced corneal inflammation and subsequent corneal neovascularization (CNV) are major causes of corneal opacity and vision loss. M1 macrophages play a central role in inflammation and CNV. Therefore, modulation of M1 macrophage polarization is a promising strategy for corneal alkali burns. Here, we illustrate the effect and underlying mechanisms of upadacitinib on corneal inflammation and CNV induced by alkali burns in mice. The corneas of BALB/c mice were administered with 1 M NaOH for 30 s and randomly assigned to the vehicle group and the upadacitinib-treated group. Corneal opacity and corneal epithelial defects were assessed clinically. Quantitative real-time PCR (qRT-PCR), immunohistochemistry, and western blot analysis were performed to detect M1 macrophage polarization and CD31⁺ corneal blood vessels. The results showed that upadacitinib notably decreased corneal opacity, and promoted corneal wound healing. On day 7 and 14 after alkali burns, upadacitinib significantly suppressed CNV. Corneal alkali injury caused M1 macrophage recruitment in the cornea. In contrast to the vehicle, upadacitinib suppressed M1 macrophage infiltration and decreased the mRNA expression levels of inducible nitric oxide synthase (iNOS), monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-1β, and vascular endothelial growth factor A (VEGF-A) in alkali-injured corneas. Moreover, upadacitinib dose-dependently inhibited M1 macrophage polarization by suppressing interferon (IFN)-γ-/lipopolysaccharide-stimulated STAT1 activation in vitro. Our findings reveal that upadacitinib can efficiently alleviate alkali-induced corneal inflammation and neovascularization by inhibiting M1 macrophage infiltration. These data demonstrate that upadacitinib is an effective drug for the treatment of corneal alkali burns.

Enriched environment promotes post-stroke angiogenesis through astrocytic interleukin-17A

Objective

Our previous studies have revealed that the protective effect of an enriched environment (EE) may be linked with astrocyte proliferation and angiogenesis. However, the relationship between astrocytes and angiogenesis under EE conditions still requires further study. The current research examined the neuroprotective effects of EE on angiogenesis in an astrocytic interleukin-17A (IL-17A)-dependent manner following cerebral ischemia/reperfusion (I/R) injury.

Methods

A rat model of ischemic stroke based on middle cerebral artery occlusion (MCAO) for 120 min followed by reperfusion was established, after which rats were housed in either EE or standard conditions. A set of behavior tests were conducted, including the modified neurological severity scores (mNSS) and the rotarod test. The infarct volume was evaluated by means of 2,3,5-Triphenyl tetrazolium chloride (TTC) staining. To evaluate the levels of angiogenesis, the protein levels of CD34 were examined by means of immunofluorescence and western blotting, while the protein and mRNA levels of IL-17A, vascular endothelial growth factor (VEGF), and the angiogenesis-associated factors interleukin-6 (IL-6), JAK2, and STAT3 were detected by western blotting and real-time quantitative PCR (RT-qPCR).

Results

We found that EE promoted functional recovery, reduced infarct volume, and enhanced angiogenesis compared to rats in standard conditions. IL-17A expression in astrocytes was also increased in EE rats. EE treatment increased the levels of microvascular density (MVD) and promoted the expression of CD34, VEGF, IL-6, JAK2, and STAT3 in the penumbra, while the intracerebroventricular injection of the IL-17A-neutralizing antibody in EE rats attenuated EE-mediated functional recovery and angiogenesis.

Conclusion

Our findings revealed a possible neuroprotective mechanism of astrocytic IL-17A in EE-mediated angiogenesis and functional recovery after I/R injury, which might provide the theoretical basis for EE in clinical practise for stroke patients and open up new ideas for the research on the neural repair mechanism mediated by IL-17A in the recovery phase of stroke.

Impaired Autophagy Causes Severe Corneal Neovascularization

PURPOSE

To investigate the role of macrophage autophagy in the process of corneal neovascularization (CNV).

METHODS

In vivo, mice CNV was induced by alkali injury and compared with rapamycin-treated alkaline burn mice. Western blot was used to determine the autophagic status of the macrophages. We quantified the levels of macrophage polarization markers (CD86, INOS, CD163, CD206) by RT-qPCR and measured inflammatory factors through ELISA (IL-6 and TNF-α) in the early phase after injury. In vitro, the human umbilical vein endothelial cells (HUVECs) were co-cultured with macrophage-conditioned medium (MCM) induced by the THP-1 cell line to simulate the neovascular microenvironment. The vascularization capacity of HUVECs was examined using the CCK-8 assay kit, tube formation assay, and scratch wound-healing assay.

RESULTS

In vivo, the mRNA expression of Beclin-1 and ATG5 was increased, together with the upregulation of M1 macrophage markers (CD86 and INOS) in corneas after early alkali injury. The area of CNV is effectively relieved in the rapamycin-treated mice. In vitro, upregulation of autophagy level by pretreatment with 3-methyladenine (3-MA) could increase the mRNA expression of the M1 markers. Macrophage-conditioned medium with impaired autophagy contains more IL-6 and TNF-α compared to the M1 macrophage-conditioned medium, promoting HUVEC proliferation, migration, and tube formation capacity. Enhancing the autophagy level with rapamycin (RAPA) could reverse this phenomenon.

CONCLUSIONS

Impaired autophagy promoted macrophage polarization toward M1 type and increased the expression of IL-6 and TNF-α, which led to severe CNV. Using the autophagy activator (RAPA) could effectively alleviate CNV by promoting autophagy.

Bioadhesive glycosylated nanoformulations for extended trans-corneal drug delivery to suppress corneal neovascularization

Eye-drop formulations as conventional regimens to tackle ocular diseases are far from efficient due to the rapid clearance by eye tears and the blockage of the corneal epithelium barrier. Here, we describe a bioadhesive glycosylated nanoplatform with boric acid pendants as a drug carrier for noninvasive trans-corneal delivery of drugs to treat corneal neovascularization (CNV), a serious corneal disease resulting in significant vision impairment. This biocompatible nanoplatform is formulated from a synthetic amphiphilic boric acid-based copolymer self-assembling to form highly stable micelles with a high loading capacity for dexamethasone (DEX). The nanoplatform is demonstrated to be in contact with the corneal epithelium for a long period under the bioadhesive function of boric acid modules and releases the drug over 96 h in a controlled manner. Our results also suggest that the nanoplatform can be efficiently internalized by corneal epithelial cells in vitro and realize transcytosis in vivo to greatly enhance the transcorneal penetration of the loaded drugs into the pathological corneal stroma. On topical application against rat corneal alkali burn, the nanoformulation presents more robust efficacy on neovascularization suppression and inflammation elimination than free DEX with a negligible effect on normal tissues. This bioadhesive strategy which focuses on extending ocular drug retention and improving trans-corneal drug delivery not only highlights an approach for alternative noninvasive therapy of CNV but also provides a versatile paradigm for other biomedical applications by overcoming protective barriers.

The Role of Inflammatory Cytokines in Neovascularization of Chemical Ocular Injury

Aim: Chemical injuries can potentially lead to the necrosis anterior segment of the eye, and cornea in particular. Inflammatory cytokines are the first factors produced after chemical ocular injuries. Inflammation via promoting the angiogenesis factor tries to implement the wound healing mechanism in the epithelial and stromal layer of the cornea. Methods: Narrative review.Results: In our review, we described the patterns of chemical injuries in the cornea and their molecular mechanisms associated with the expression of inflammatory cytokines. Moreover, the effects of inflammation signals on angiogenesis factors and CNV were explained. Conclusion: The contribution of inflammation and angiogenesis causes de novo formation of blood vessels that is known as the corneal neovascularization (CNV). The new vascularity interrupts cornea clarity and visual acuity. Inflammation also depleted the Limbal stem cells (LSCs) in the limbus causing the failure of normal corneal epithelial healing and conjunctivalization of the cornea.

Interleukin-17: The Role for Pathological Angiogenesis in Ocular Neovascular Diseases

Ocular neovascular diseases are featured by abnormal angiogenesis in the eye, and they seriously threaten the human visual health. These diseases include proliferative diabetic retinopathy (PDR), age-related macular degeneration (AMD), retinopathy of prematurity (ROP), and retinal vein occlusion (RVO). In fact, ocular neovascular diseases represent the leading causes of vision impairment and blindness worldwide. Ocular neovascularization, the process of pathological vessel formation in eye, underlies ocular neovascular diseases. Cytokines have important regulatory roles in neovascularization through immunological networks. Interleukin (IL)-17, the signature cytokine produced by T helper 17 (Th17) cells, has proven to be involved in ocular neovascularization. However, roles of IL-17 in ocular neovascular diseases still remain controversial. This review provides an overview of the functional roles of IL-17 in ocular neovascular diseases from basic research to clinical evidence by focusing on PDR, AMD, ROP, and RVO. The possible roles of IL-17 in neovascularization are achieved through a regulatory network of cytoskeleton remodeling, vascular endothelial growth factor (VEGF), VEGF-related cytokines, and complement components. Current applications as well as potential therapies targeting IL-17 with genome editing systems are also outlined and discussed. Targeting IL-17 might be a promising therapeutic strategy against ocular neovascular diseases.

The long-term effect of tacrolimus on alkali burn-induced corneal neovascularization and inflammation surpasses that of anti-vascular endothelial growth factor

Purpose

To investigate the effect of tacrolimus in alkali burn-induced corneal neovascularization (NV) and inflammation and to compare with anti-vascular endothelial growth factor (anti-VEGF).

Methods

After corneal alkali-burn, 84 Wistar rats were randomly divided into three groups and received either saline solution or 0.05% tacrolimus (0.5 mg/mL) four times daily, or subconjunctival anti-VEGF injection (0.5 mg/0.05 mL). Corneal NV, opacity and epithelial defects, the status of inflammation, and the levels of proinflammatory and angiogenic cytokines were assessed on Days 3, 7, 14 and 28 post-injury.

Results

Compared with the control, tacrolimus significantly reduced corneal NV on Days 7, 14 and 28 post-injury, and anti-VEGF significantly reduced corneal NV at each assessment. Nevertheless, the tacrolimus group had significantly less corneal NV than the anti-VEGF group on Days 14 and 28. Furthermore, both tacrolimus and anti-VEGF significantly decreased the VEGF-A expression on Days 7 and 14, with no significant difference between the two groups. Moreover, corneal inflammatory response was alleviated, and corneal opacity and epithelial defects were significantly reduced by tacrolimus. Additionally, the expression of IL-1β, IL-6, monocyte chemotactic protein-1, macrophage inflammatory protein-1α and TGF-β were significantly decreased by tacrolimus.

Conclusion

Our findings suggested that 0.05% tacrolimus suspension eye drops effectively reduced alkali burn-induced corneal NV and inflammation, with a better effect than subconjunctival anti-VEGF injections on Days 14 and 28.