Engineering extracellular vesicles with macrophage membrane fusion for ameliorating imiquimod-induced psoriatic skin inflammation.

INTRODUCTION: Herein, we developed an engineered extracellular vehicle (EV)-based method for ameliorating inflammatory responses in psoriasis. METHODS: EVs, derived from annexin A1 (ANXA1) overexpressing T cells, were co-extruded with M2 macrophage membrane to obtain engineered EVs. In vitro, the effect of engineered EVs on macrophage polarization was evaluated by real-time PCR. In imiquimod (IMQ)-induced psoriasis-like mouse model, the efficacy of engineered EVs in ameliorating psoriatic inflammation was evaluated by Psoriasis Area and Severity Index (PASI) score and immunohistochemistry staining after subcutaneous injection of EVs. RESULTS: The engineered EVs not only preserved the high stability of M2 macrophage membrane but also retained the macrophage reprogramming potential of ANXA1 overexpressed in T cells. In the psoriasis-like mouse model, subcutaneous injection of engineered EVs successfully reduced the PASI score and the levels of pro-inflammatory cytokines, including IL-1ß, IL-6, and TNF-α. Along with high biosafety, the administration of EVs also rescued the histomorphological changes of spleen, liver, and kidney. CONCLUSIONS: The engineered EVs exhibited the potential to alleviate inflammation of psoriasis, providing new insights and potential strategies for the immunotherapies of psoriasis.

Sex differences in the association between plasma polyunsaturated fatty acids levels and moderate-to-severe plaque psoriasis severity: a cross-sectional and longitudinal study.

BACKGROUND: Psoriasis is a chronic inflammatory skin disease with metabolic abnormalities serving as important contributors for pathogenesis and progression. Polyunsaturated fatty acids (PUFAs) have been found to be associated with human diseases, including psoriasis. However, differences and controversies exist regarding their content and roles. METHODS: Plasma PUFAs concentrations were measured in 296 patients with moderate-to-severe plaque psoriasis from the Shanghai Psoriasis Effectiveness Evaluation CoHort. Disease severity was assessed using Clinician-Reported Outcomes (ClinROs), including Psoriasis Area and Severity Index (PASI), Body Surface Area (BSA) and Physician Global Assessment (PGA), as well as Patient-Reported Outcomes (PROs), including Patient Global Assessment (PtGA) and Dermatology Life Quality Index (DLQI). Multivariate generalized linear regression models (GLMs), subgroup and interaction analysis, and restricted cubic spline were used to estimate the cross-sectional associations between PUFAs concentrations and disease severity. Longitudinal assessments of PASI scores and PASI response were conducted at a 12-week follow-up. Associations between baseline plasma PUFAs levels and prospective PASI scores or PASI response were assessed using multivariate GLMs or logistic regression models. RESULTS: Males suffered severer psoriasis and presented lower plasma docosahexaenoic acid (DHA) and arachidonic acid (ARA) levels compared to females. Among males, plasma eicosadienoic acid (EDA) level was positively associated with PASI, BSA and PGA scores, while total Omega-3 PUFAs and/or eicosapentaenoic acid (EPA) levels exhibited non-linear associations with PASI and/or BSA scores. α-Linolenic acid (ALA) was negatively, whereas ARA was positively, associated with DLQI scores. In females, Omega-3 PUFAs, including EPA, DHA, and total Omega-3 PUFAs, showed inverse associations with PASI and BSA scores. Longitudinally, plasma total Omega-6 PUFAs were positively associated with the likelihood of achieving PASI 100 at 12 weeks in males. In females, concentrations of dohomo-γ-linolenic acid were prospectively associated with an increase in PASI scores, and DHA was associated with the likelihood of achieving PASI 75 and PASI 90 decline. CONCLUSIONS: Sex differences cross-sectionally exist in disease severity and plasma PUFAs levels. The association between PUFAs and psoriasis severity also varies cross-sectionally and longitudinally between males and females. Sex differences should be considered when studying the function and clinical application of PUFAs in psoriasis.

The role of microRNA in psoriasis: A review.

Psoriasis is a chronic immune-mediated inflammatory skin disease that involves a complex interplay between infiltrated immune cells and keratinocytes. Great progress has been made in the research on the molecular mechanism of coding and non-coding genes, which has helped in clinical treatment. However, our understanding of this complex disease is far from clear. MicroRNAs (miRNAs) are small non-coding RNA molecules that are involved in post-transcriptional regulation, characterised by their role in mediating gene silencing. Recent studies on miRNAs have revealed their important role in the pathogenesis of psoriasis. We reviewed the current advances in the study of miRNAs in psoriasis; the existing research has found that dysregulated miRNAs in psoriasis notably affect keratinocyte proliferation and/or differentiation processes, as well as inflammation progress. In addition, miRNAs also influence the function of immune cells in psoriasis, including CD4+ T cells, dendritic cells, Langerhans cells and so on. In addition, we discuss possible miRNA-based therapy for psoriasis, such as the topical delivery of exogenous miRNAs, miRNA antagonists and miRNA mimics. Our review highlights the potential role of miRNAs in the pathogenesis of psoriasis, and we expect more research progress with miRNAs in the future, which will help us understand this complex skin disease more accurately.

Implications of LncRNAs and CircRNAs in psoriasis: a review.

Psoriasis is a chronic inflammatory skin disease characterized by skin infiltration of immune cells and abnormal epidermal thickening. The initial pathogenesis has not been fully elucidated. Non-coding RNAs (ncRNAs), which include long ncRNAs (lncRNAs) and circular RNAs (circRNAs), comprise the majority of genome transcripts and are important influencers of gene transcription and post-transcription modulations. Emerging roles of ncRNAs in psoriasis were identified recently. This review summarizes the existing studies of psoriasis-related lncRNAs and circRNAs. A considerable proportion of the studied lncRNAs and circRNAs regulate keratinocyte mobility, such as keratinocyte proliferation and differentiation. Some lncRNAs and circRNAs are tightly related to keratinocyte inflammation reactions. Other reports demonstrated that they are also implicated in modulating immune cell differentiation, proliferation, and activation. This review might illuminate future psoriasis research and highlight that lncRNAs and circRNAs might act as therapeutic targets.

Abnormal lipid metabolism in epidermal Langerhans cells mediates psoriasis-like dermatitis.

Psoriasis is a chronic, inflammatory skin disease, frequently associated with dyslipidemia. Lipid disturbance in psoriasis affects both circulatory system and cutaneous tissue. Epidermal Langerhans cells (LCs) are tissue-resident DCs that maintain skin immune surveillance and mediate various cutaneous disorders, including psoriasis. However, the role of LCs in psoriasis development and their lipid metabolic alternation remains unclear. Here, we demonstrate that epidermal LCs of psoriasis patients enlarge with longer dendrites and possess elevated IL-23p19 mRNA and a higher level of neutral lipids when compared with normal LCs of healthy individuals. Accordantly, epidermal LCs from imiquimod-induced psoriasis-like dermatitis in mice display overmaturation, enhanced phagocytosis, and excessive secretion of IL-23. Remarkably, these altered immune properties in lesional LCs are tightly correlated with elevated neutral lipid levels. Moreover, the increased lipid content of psoriatic LCs might result from impaired autophagy of lipids. Bulk RNA-Seq analysis identifies dysregulated genes involved in lipid metabolism, autophagy, and immunofunctions in murine LCs. Overall, our data suggest that dysregulated lipid metabolism influences LC immunofunction, which contributes to the development of psoriasis, and therapeutic manipulation of this metabolic process might provide an effective measurement for psoriasis.

IL-17A Promotes Psoriasis-Associated Keratinocyte Proliferation through ACT1-Dependent Activation of YAP-AREG Axis.

Psoriasis is a recurrent inflammatory skin disorder characterized by epidermal hyperplasia, which is primarily driven by IL-17A. The Hippo-YAP signaling pathway plays a vital role in cell survival and tissue growth, and its target gene, AREG, has been reported to promote the development of psoriasis. However, whether IL-17A promotes keratinocyte proliferation through regulating Hippo-YAP signaling has not been explored. In this study, we show that the YAP-AREG pathway is activated in human psoriatic skin and is suppressed by IL-17A antagonist secukinumab and that imiquimod and IL-17A administration activates the YAP-AREG axis in mice epidermis. In vitro studies using HaCaT and normal human epidermal keratinocyte cells suggest that IL-17A enhances AREG expression and keratinocyte proliferation by activating Hippo-YAP signaling. Mechanistically, IL-17A stimulates the recruitment of MST1 to ACT1 in keratinocytes, which leads to reduced MST1-LATS1 interaction and YAP dephosphorylation. Together, our findings reveal a previously unknown mechanism in which IL-17A promotes keratinocyte proliferation in psoriasis, namely through activating YAP-AREG signaling.

Human umbilical cord-derived mesenchymal stem cells ameliorate psoriasis-like dermatitis by suppressing IL-17-producing γδ T cells.

Mesenchymal stem cells (MSCs) have shown great potential in treating autoimmune diseases due to their immunomodulatory capability, which has been verified in both animal experiments and clinical trials. Psoriasis is a chronic and remitting immune-related disease. Limited studies have demonstrated that MSCs might be an effective therapeutic approach for managing psoriasis, whose underlying mechanism remains to be elucidated. In our present study, human umbilical cord-derived MSCs (hUC-MSCs) were subcutaneously injected into mice with imiquimod (IMQ)-induced psoriasis-like skin inflammation to explore the feasibility of this cellular therapy. The severity of psoriasis-like dermatitis was evaluated by cumulative psoriasis area and severity index score and epidermal thickness of skin tissue sections. Flow cytometric analysis was utilized to detect T helper cells, regulatory T cells, and γδ T cells in skin-draining lymph nodes. Real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay were used to assess the expression levels of psoriasis-related cytokines and chemokines in mouse dorsal skin lesions. We discovered that hUC-MSCs drastically diminished the severity of IMQ-induced psoriasis-like dermatitis and suppressed inflammatory cell response. Although the tail vein injection of hUC-MSCs was also effective, it was correlated with higher mortality owing to pulmonary embolism. By comparison, subcutaneous injection with two million hUC-MSCs was identified to be the optimal therapeutic strategy. Furthermore, we uncovered that hUC-MSCs might repress skin inflammation probably through inhibiting interleukin-17-producing γδ T cells. In conclusion, subcutaneous administration of hUC-MSCs might be a promising therapeutic approach for psoriasis. Our findings provide novel insights into the underpinning mechanism of hUC-MSC treatment in the management of psoriasis.

Xiao-Yin-Fang Therapy Alleviates Psoriasis-like Skin Inflammation Through Suppressing γδT17 Cell Polarization.

Psoriasis is an immune-mediated chronic inflammatory skin disease primarily mediated by the activation of interleukin (IL)-17-producing T cells. Traditional Chinese Medicine (TCM) represents one of the most effective complementary and alternative medicine (CAM) agents for psoriasis, which provides treasured sources for the development of anti-psoriasis medications. Xiao-Yin-Fang (XYF) is an empirically developed TCM formula that has been used to treat psoriasis patients in Shanghai Changhai Hospital for over three decades. Imiquimod (IMQ)-induced psoriasis-like dermatitis mouse model was utilized to investigate the therapeutic effects of XYF by the assessment of disease severity and skin thickness. Flow cytometric assay was performed to explore the influence of XYF on skin-related immunocytes, primarily T cells. And, RNA sequencing analysis was employed to determine the alternation in gene expression upon XYF therapy. We discovered that XYF alleviated psoriasis-like skin inflammation mainly through suppressing dermal and draining lymph-node IL-17-producing γδT (γδT17) cell polarization. Moreover, XYF therapy ameliorated the relapse of psoriasis-like dermatitis and prohibited dermal γδT cell reactivation. Transcriptional analysis suggested that XYF might regulate various inflammatory signaling pathways and metabolic processes. In conclusion, our results clarified the therapeutic efficacy and inner mechanism of XYF therapy in psoriasis, which might promote its clinical application in psoriasis patients and facilitate the development of novel anti-psoriasis drugs based on the bioactive components of XYF.

Infliximab modifies regulatory T cells and co-inhibitory receptor expression on circulating T cells in psoriasis.

BACKGROUND: Psoriasis is a T cell-mediated autoimmune skin disease. Accumulating evidence has demonstrated that co-inhibitory receptors (CIRs) play a vital role in regulating T cell-mediated immune response, especially in neoplasm and autoimmunity. However, the immuno-function of CIRs in the development of psoriasis remains unclear. OBJECTIVE: We investigated the expression of CIRs on the circulating T lymphocytes of psoriasis patients before and after anti-tumor necrosis factor-α (TNF-α) therapy. METHODS: We enrolled 17 patients with moderate-to-severe plaque psoriasis, 17 patients with mild plaque psoriasis, and 18 healthy controls in this study. Fourteen of the moderate-to-severe psoriasis patients were treated with infliximab, a monoclonal antibody against TNF-α. Peripheral blood was collected, and peripheral blood mononuclear cells were extracted. The proportion of T cell subsets along with their expression of CIRs, namely T cell immunoreceptor with Ig and ITIM domains (TIGIT), lymphocyte activating gene 3 (LAG-3), cytotoxic T-lymphocyte associated protein 4 (CTLA-4), B and T lymphocyte-associated protein (BTLA), endothelial protein C receptor (PROCR), podoplanin (PDPN), programmed cell death 1 (PD-1), and T cell immunoglobulin mucin family containing molecule 3 (TIM-3), were determined by flow cytometric assay. RESULTS: The moderate-to-severe plaque psoriasis patients had less circulating Tregs, which increased after infliximab treatment. They also had decreased TIGIT, LAG-3 but increased PDPN expression on peripheral CD4+ T cells. Infliximab enhanced TIGIT, LAG-3, CTLA-4 but reduced PROCR expression on circulating CD4+ T cells. Remarkably, both the frequency of circulating Tregs and the expression level of TIGIT on CD4+ T cells at baseline (pre-treatment) negatively correlated with the extent of PASI score reduction benefited from infliximab therapy. CONCLUSION: Anti-TNF-α therapy increased the frequency of Tregs and TIGIT, LAG-3, CTLA-4 expression but reduced PROCR expression on circulating CD4+ T cells in psoriasis patients. The baseline proportion of Tregs and the expression level of TIGIT on circulating CD4+ T cells might serve as predictive markers for the degree of disease remission benefited from infliximab treatment.

Dysregulated Peripheral Invariant Natural Killer T Cells in Plaque Psoriasis Patients.

Background: Psoriasis is a common immune-mediated skin disease that involves T-cell-mediated immunity. Invariant natural killer T (iNKT) cells are a unique lymphocyte subpopulation that share properties and express surface markers of both NK cells and T cells. Previous reports indicate that iNKT cells regulate the development of various inflammatory diseases. IL-17 is a key cytokine in the pathogenesis of psoriasis and a key therapeutic target. Secukinumab is a fully human IgG1κ antibody that targets IL-17A, thereby antagonizing the biological effects of IL-17. Objective: To explore the expression of iNKT cells in psoriasis patients and the effect of secukinumab on them. Methods: We examined the frequencies of iNKT cells, Tregs, naïve and memory CD4+and CD8+T cells in the PBMCs as well as their cytokine production in a cohort of 40 patients with moderate-to-severe plaque psoriasis and 40 gender- and age-matched healthy controls. We further collected peripheral blood of another 15 moderate-to-severe plaque psoriasis patients who were treated with secukinumab and evaluated the proportion of iNKT cells in the PBMCs at baseline and week 12. Results: The frequencies of conventional CD4+ T cells, CD8+ T cells, and Tregs in the PBMCs were comparable between psoriasis patients and healthy controls, but the frequencies of Th17 cells, Tc1 cells and Tc17 cells were increased in psoriasis patients. The frequency of peripheral iNKT cells and CD69+ iNKT cells was significantly decreased in psoriasis patients. Both iNKT2 cells and iNKT17 cells were increased in psoriasis patients, but the ratio of iNKT2 cells vs iNKT17 cells was significantly reduced in psoriasis patients. After receiving secukinumab, the proportion of iNKT cells in the PBMCs of patients was increased, while the proportion of iNKT17 cells was decreased. Conclusion: Dysregulated iNKT cells may be involved in the pathogenesis of psoriasis and secukinumab may play a regulatory role on iNKT cells.

High-throughput transcriptome and pathogenesis analysis of clinical psoriasis.

BACKGROUND: Previous psoriasis studies have mostly focused on skin-related immunology, but the exact mechanisms remain elusive. Clinical evidence, such as higher morbidity among obese individuals and emotional factors, indicate that psoriasis is a complex systemic disease. High-throughput transcriptome analysis provides an effective method to comprehensively assess the disease. OBJECTIVE: The present study is aiming to understand transcriptome changes of clinical psoriasis skins and comprehensively assess the diseases using pathways analysis. METHODS: We performed transcriptome sequence of clinical psoriatic samples. Biological pathway analyses were conducted using differentially expressed RNAs, as well as identified competing endogenous RNAs (ceRNAs). qRT-PCR and histological immunofluorescence staining was conducted to verify the differentially expressed RNAs (DE_RNAs) and the three important enriched biological pathways. RESULTS: Numerous DE_RNAs were identified between psoriasis patients and healthy people. Functional analysis indicated PPAR-fatty acids metabolism pathways, neural-hormone regulations, circadian entrainment were the three mostly appeared pathways. For PPAR-fatty acids metabolism pathways, the expression of seven randomly selected genes, including ACSBG1, ACOT2), CYP27A1, ELOVL3, FABP7, FADS2 and PPARG were all significantly decreased in psoriasis lesions. For neural-hormone regulation pathways, the expression of CFL1, EPHA2, HRAS were all significantly upregulated in psoriasis lesions. While the expression of four randomly selected genes from circadian entrainment pathways, including CRY2, PER3, NR1D1 and RORC were all significantly downregulated. Histological immunofluorescence staining of FADS2, EPHA2 and CRY2 were consistent with their genes' expressions. CONCLUSION: Our results revealed transcriptome changes of psoriasis, and indicated three important pathways involved in psoriasis, including PPAR-fatty acids metabolism pathways, neural-hormone regulations, circadian entrainment.

Erianin alleviates diabetic retinopathy by reducing retinal inflammation initiated by microglial cells via inhibiting hyperglycemia-mediated ERK1/2-NF-κB signaling pathway.

Blood-retinal barrier (BRB) breakdown is a typical event in the early stage of diabetic retinopathy (DR). This study aims to elucidate the protection of erianin, a natural compound isolated from Dendrobium chrysotoxum Lindl, against DR development. Erianin alleviated BRB breakdown and rescued the reduced claudin1 and occludin expression in retinas from streptozotocin-induced diabetic mice. Erianin reduced microglial activation, ERK1/2 phosphorylation, NF-κB transcriptional activation, and the elevated TNF-α expression both in vitro and in vivo. ERK1/2 inhibitor U0126 abrogated NF-κB activation in d-glucose-treated BV2 cells. Erianin reduced cellular glucose uptake, and molecular docking analysis indicated the potential interaction of erianin with glucose transporter (GLUT)1. GLUT1 inhibitor (STF31) reduced the activation of the ERK1/2-NF-κB signaling pathway. Coculture with d-glucose-stimulated microglial BV2 cells and with TNF-α stimulation both induced inner BRB and outer BRB damage in human retinal endothelial cells and APRE19 cells, but erianin improved all these damages. In summary, erianin attenuated BRB breakdown during DR development by inhibiting microglia-triggered retinal inflammation via reducing cellular glucose uptake and abrogating the subsequent activation of the downstream ERK1/2-NF-κB pathway. Moreover, erianin also alleviated BRB damage induced by TNF-α released from the activated microglia.-Zhang, T., Ouyang, H., Mei, X., Lu, B., Yu, Z., Chen, K., Wang, Z., Ji, L. Erianin alleviates diabetic retinopathy by reducing retinal inflammation initiated by microglial cells via inhibiting hyperglycemia-mediated ERK1/2-NF-κB signaling pathway.

Ginsenoside compound K ameliorates imiquimod-induced psoriasis-like dermatitis through inhibiting REG3A/RegIIIγ expression in keratinocytes.

BACKGROUND: Psoriasis is a chronic inflammatory skin disease characterized by keratinocyte hyperproliferation. Ginsenoside compound K (CK), a bioactive metabolite of ginseng, modulates various skin disorders with an impact on keratinocyte biology. However, the effect of Ginsenoside CK in psoriasis has not been explored. OBJECTIVE: Our aim was to investigate whether ginsenoside CK could affect the homeostasis of keratinocytes and their expression of psoriasis-associated antimicrobial protein regenerating islet-derived protein 3-alpha (REG3A) and its murine ortholog RegIIIγ. We further explored the therapeutic potential of ginsenoside CK in imiquimod (IMQ)-induced psoriasis-like dermatitis. METHODS: The effects of ginsenoside CK in cell growth and apoptosis of human keratinocytes were measured by MTT assay and flow cytometry, respectively. Bax levels were evaluated by Western blot in HaCaT cells following ginsenoside CK stimulation. REG3A levels were assessed by RT-PCR and Western blot in human keratinocytes following interleukin (IL)-36γ and ginsenoside CK co-simulation. Utilizing IMQ-induced psoriasis mouse model, the therapeutic effects of 0.1% and 1% ginsenoside CK cream were assessed by skin thicknesses and histological examinations, and RegIIIγ level in the lesional skin was detected by Western blot and immunofluorescence. RESULTS: Ginsenoside CK prohibited human keratinocyte proliferation but did not affect their apoptosis. Moreover, it inhibited IL-36γ-induced REG3A expression in HaCaT cells. Ginsenoside CK alleviated imiquimod-induced psoriasis-like hyperkeratosis and reduced RegIIIγ expression in the keratinocytes from lesional skin. CONCLUSION: Ginsenoside CK ameliorated IMQ-induced psoriasis-like dermatitis possibly through inhibiting REG3A/RegIIIγ expression in keratinocytes, which highlighted a therapeutic potential of ginsenoside CK in psoriasis.

Natural flavonoid galangin alleviates microglia-trigged blood-retinal barrier dysfunction during the development of diabetic retinopathy.

Hyperglycemia-induced blood-retinal barrier (BRB) breakdown is an early and typical event of diabetic retinopathy (DR). Although chronic inflammation plays an important role in DR development, the concrete mechanism remains unclear. This study aims to investigate the role of microglia cells-triggered inflammatory response in hyperglycemia-induced BRB breakdown and the amelioration of galangin, a natural flavonoid. Galangin alleviated BRB breakdown in streptozotocin-induced diabetic mice. D-glucose (25 mM)-stimulated microglia BV2 cells induced BRB damage in vitro, but galangin reversed this injury. Galangin decreased the activation of microglia cells, ROS formation, the phosphorylation of extracellular-signal-regulated protein kinase (ERK)1/2, the transcriptional activation of nuclear factor κB (NFκB) and early growth response (Egr1) protein, and the elevated expression of tumor necrosis factor (TNF)-α both in vitro and in vivo. ERK1/2 inhibitor U0126 reduced ROS formation, the activation of NFκB and Egr1, and the elevated TNFα expression in D-glucose-stimulated BV2 cells. N-acetylcysteine, a well-known antioxidant, abrogated D-glucose-induced NFκB and Egr1 activation in BV2 cells. Galangin also reversed the decreased expression of claudin1 and occludin, and the increased BRB injury and ROS formation in TNFα-treated human retinal endothelial cells (HRECs) and ARPE19 cells. Galangin induced the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) in both HRECs and ARPE19 cells. Moreover, the galangin-provided attenuation on BRB breakdown was diminished in Nrf2 knockout diabetic mice. In conclusion, galangin alleviated DR by attenuating BRB damage via inhibiting microglia-triggered inflammation and further reversing TNFα-induced BRB dysfunction by abrogating oxidative stress injury via activating Nrf2.

Erianin inhibits high glucose-induced retinal angiogenesis via blocking ERK1/2-regulated HIF-1α-VEGF/VEGFR2 signaling pathway.

Erianin is a natural compound found in Dendrobium chrysotoxum Lindl. Diabetic retinopathy (DR) is a serious and common microvascular complication of diabetes. This study aims to investigate the inhibitory mechanism of erianin on retinal neoangiogenesis and its contribution to the amelioration of DR. Erianin blocked high glucose (HG)-induced tube formation and migration in choroid-retinal endothelial RF/6A cells. Erianin inhibited HG-induced vascular endothelial growth factor (VEGF) expression, hypoxia-inducible factor 1-alpha (HIF-1α) translocation into nucleus and ERK1/2 activation in RF/6A and microglia BV-2 cells. MEK1/2 inhibitor U0126 blocked HG-induced HIF-1α and ERK1/2 activation in both above two cells. In addition, erianin abrogated VEGF-induced angiogenesis in vitro and in vivo, and also inhibited VEGF-induced activation of VEGF receptor 2 (VEGFR2) and its downstream cRaf-MEK1/2-ERK1/2 and PI3K-AKT signaling pathways in RF/6A cells. Furthermore, erianin reduced the increased retinal vessels, VEGF expression and microglia activation in streptozotocin (STZ)-induced hyperglycemic and oxygen-induced retinopathy (OIR) mice. In conclusion, our results demonstrate that erianin inhibits retinal neoangiogenesis by abrogating HG-induced VEGF expression by blocking ERK1/2-mediated HIF-1α activation in retinal endothelial and microglial cells, and further suppressing VEGF-induced activation of VEGFR2 and its downstream signals in retinal endothelial cells.

Lonicerae Japonicae Flos attenuates diabetic retinopathy by inhibiting retinal angiogenesis.

ETHNOPHARMACOLOGICAL RELEVANCE: Lonicerae Japonicae Flos (Jin-Yin-Hua) is a well-known traditional Chinese medicine used for clearing away heat and toxic material. AIM OF THE STUDY: This study aims to observe the attenuation of aqueous extract of Lonicerae Japonicae Flos (FL) against streptozotocin (STZ)-induced diabetic retinopathy (DR) and its engaged mechanism. MATERIALS AND METHODS: STZ-induced proliferative DR (PDR) for 5 month in C57BL/6 mice was used in this study. Retinal vessels were observed by immunofluorescence staining with cluster of differentiation 31 (CD31) and histopathological evaluation. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum vascular endothelial growth factor (VEGF) content. Cell proliferation was detected by 3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyltetrazolium bromide (MTT) assay in choroid-retinal endothelial RF/6A cells. VEGF-induced tube formation in RF/6A cells was observed. The contents of chlorogenic acid (CGA), caffeic acid (CA), and luteolin in FL were detected by high-performance liquid chromatography (HPLC). RESULTS: Histopathological evaluation demonstrated that retinal vessels were increased in STZ-induced PDR mice, whereas FL decreased such increase. The results of CD31 staining also showed that FL decreased the increased number of retinal vessels in STZ-induced PDR mice. In addition, FL reduced the increased serum VEGF content in STZ-induced PDR mice. FL reduced VEGF-induced RF/6A cell proliferation in the concentration-dependent manner, but had no obvious effect on RF/6A cell viability without VEGF stimulation. VEGF-induced tube formation in RF/6A cells was inhibited by different concentrations of FL. CGA, CA and luteolin all inhibited VEGF-induced tube formation in RF/6A cells, and the lowest effective concentration of CGA and CA was both 0.625µM, but of luteolin was 5µM. Furthermore, the results of HPLC demonstrated that the amount of CGA was the highest in FL. CONCLUSIONS: FL ameliorates STZ-induced PDR by inhibiting retinal angiogenesis. Phenolic acid CGA is the main compound contributing to the inhibition of FL on retinal angiogenesis.

The Development of Diabetic Retinopathy in Goto-Kakizaki Rat and the Expression of Angiogenesis-Related Signals.

The Goto-Kakizaki (GK) rat is a genetic model of type 2 diabetes. Diabetic retinopathy (DR) is a common complication of diabetes. In this study, we observed the development of DR in GK rats and the expression of some angiogenesis-related signals. GK rats were housed for 5, 6 and 7 months. Results of retinal vessels stained by cluster of differentiation 31 (CD31) showed that the number of retinal vessels was increased in GK rats at both 6 and 7 months. Retinal histological observation also evidenced such increase. Retinal mRNA expression of hypoxia inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), VEGFB and its receptors (VEGFR1/2), basic fibroblast growth factor (bFGF), and platelet-derived growth factor (PDGF) A/B was increased in GK rats at both 6 and 7 months. Retinal mRNA expressions of matrix metalloproteinase (MMP) 2/9 and insulin-like growth factor 1 (IGF-1) were increased at 7 months. Retinal mRNA expression of pigment epithelium-derived factor (PEDF) was increased in GK rats at 6 months. Serum contents of VEGF, bFGF, PDGFA, MMP2/9, IGF-1, PEDF were increased in GK rats at both 6 and 7 months, while PDGFB was increased at 7 months. In summary, our results indicate that retinal angiogenesis occurred in GK rats at 6 and 7 months, and the expressions of some angiogenesis related factors were increased during the development of DR in GK rats.

Andrographolide ameliorates diabetic retinopathy by inhibiting retinal angiogenesis and inflammation.

BACKGROUND: Andrographolide (Andro) is the main compound distributed in medicinal herb Andrographis paniculata. This study aims to observe the amelioration of Andro on streptozotocin (STZ)-induced diabetic retinopathy (DR) in mice. METHODS: STZ-induced non-proliferative DR (NPDR) for 2 months and proliferative DR (PDR) for 5 month in C57BL/6 mice were used in this study, respectively. Retinal vessels were observed by immunofluorescence staining for cluster of differentiation 31 (CD31). Evans blue permeation assay was used to detect the breakdown of blood-retinal barrier (BRB). Real-time PCR and immune-blot were used to detect mRNA and protein expression. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1ß. RESULTS: Retinal immunofluorescence staining with CD31 showed that Andro reduced the increased retinal vessels in STZ-induced PDR mice. Evans blue permeation results demonstrated that Andro attenuated the breakdown of BRB in STZ-induced NPDR mice. In STZ-induced PDR mice, Andro decreased the increased vascular endothelial growth factor (VEGF) in serum and vitreous cavity, and reduced the increased retinal mRNA expression of VEGF and its receptors. In STZ-induced NPDR mice, Andro abrogated the nuclear translocation of nuclear factor κB (NF-κB) p65 and early growth response-1 (Egr-1), and reduced the increased phospho-NF-κBp65, -inhibitor of kappa B (IκB), and -IκB kinase (IKK). Andro also decreased the increased serum and retinal mRNA expression of TNF-α, IL-6, IL-1ß, serpine1, and tissue factor (TF). CONCLUSIONS: Andro ameliorates DR via attenuating retinal angiogenesis and inflammation, and VEGF, NF-κB, and Egr1 signaling pathways all play important roles in this process.

Dendrobium chrysotoxum Lindl. alleviates diabetic retinopathy by preventing retinal inflammation and tight junction protein decrease.

Diabetic retinopathy (DR) is a serious complication of diabetes mellitus. This study aimed to observe the alleviation of the ethanol extract of Dendrobium chrysotoxum Lindl. (DC), a traditional Chinese herbal medicine, on DR and its engaged mechanism. After DC (30 or 300 mg/kg) was orally administrated, the breakdown of blood retinal barrier (BRB) in streptozotocin- (STZ-) induced diabetic rats was attenuated by DC. Decreased retinal mRNA expression of tight junction proteins (including occludin and claudin-1) in diabetic rats was also reversed by DC. Western blot analysis and retinal immunofluorescence staining results further confirmed that DC reversed the decreased expression of occludin and claudin-1 proteins in diabetic rats. DC reduced the increased retinal mRNA expressions of intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor α (TNFα), interleukin- (IL-) 6, and IL-1ß in diabetic rats. In addition, DC alleviated the increased 1 and phosphorylated p65, IκB, and IκB kinase (IKK) in diabetic rats. DC also reduced the increased serum levels of TNFα, interferon-γ (IFN-γ), IL-6, IL-1ß, IL-8, IL-12, IL-2, IL-3, and IL-10 in diabetic rats. Therefore, DC can alleviate DR by inhibiting retinal inflammation and preventing the decrease of tight junction proteins, such as occludin and claudin-1.

Ethanol extract of Dendrobium chrysotoxum Lindl ameliorates diabetic retinopathy and its mechanism.

Diabetic retinopathy (DR) is the most common and serious complication of diabetes mellitus (DM). The present study investigates the amelioration of ethanol extract of Dendrobium chrysotoxum Lindl (DC) on streptozotocin (STZ)-induced DR and its engaged mechanism. Retinal immunofluorescence staining with cluster of differentiation 31 (CD31) demonstrated that DC (30-300 mg/kg) decreased the increased retinal vessels in STZ-induced diabetic rats. Retinal histopathological observation also showed that retinal vessels were decreased in DC-treated diabetic rats. DC decreased the increased retinal mRNA expression of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) in diabetic rats, and DC also decreased the elevated serum VEGF level. Immunohistochemical staining further evidenced that DC decreased VEGF and VEGFR2 expression in retinas. Retinal mRNA expression of matrix metalloproteinase (MMP) 2/9 was decreased in DC (300 mg/kg)-treated diabetic rats. Serum levels of MMP 2/9, basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF) A/B, insulin-like growth factor 1 (IGF-1), interleukin 1ß (IL-1ß), and IL-6 were all decreased in DC-treated diabetic rats. In addition, DC decreased the increased phosphorylation of p65 and the increased expression of intercellular adhesion molecule-1 (ICAM-1). In conclusion, DC can alleviate retinal angiogenesis during the process of DR via inhibiting the expression of VEGF/VEGFR2, and some other pro-angiogenic factors such as MMP 2/9, PDGF A/B, bFGF, IGF-1. In addition, DC can also ameliorate retinal inflammation via inhibiting NFκB signaling pathway.