Angiogenesis In Diabetic Retinopathy Research Articles

Altered Functionality of Lipoprotein(a) Impacts on Angiogenesis in Diabetic Retinopathy.

Diabetic retinopathy (DR) is a complication of type 2 diabetes mellitus (T2DM). Lipoprotein(a) (Lp(a)) contributes to the progression of DR, but how is unclear. In homeostasis of the retinal microvasculature, myeloid-derived pro-angiogenic cells (PACs) also play a pivotal role, and fail to function properly in diabetic conditions. Here, we explored the putative contribution of Lp(a) from patients with T2DM with/without DR and healthy controls on inflammation and angiogenesis of retinal endothelial cells (RECs), and on PAC differentiation. Subsequently, we compared the lipid composition of Lp(a) from patients to that from healthy controls. Lp(a)/LDL obtained from patients and healthy controls were added to TNF-alpha-activated RECs. Expression of VCAM-1/ICAM-1 was measured using flowcytometry. Angiogenesis was determined in REC-pericyte co-cultures stimulated by pro-angiogenic growth factors. PAC differentiation from peripheral blood mononuclear cells was determined by measuring expression of PAC markers. The lipoprotein lipid composition was quantified using detailed lipidomics analysis. Lp(a) from patients with DR (DR-Lp(a)) failed to block TNF-alpha-induced expression of VCAM-1/ICAM-1 in REC whereas Lp(a) from healthy controls (healthy control [HC]-Lp(a)) did. DR-Lp(a) increased REC angiogenesis more than HC-Lp(a) did. Lp(a) from patients without DR showed intermediate profiles. HC-Lp(a) reduced the expression of CD16 and CD105 in PAC, but T2DM-Lp(a) did not. Phosphatidylethanolamine content was lower in T2DM-Lp(a) than in HC-Lp(a). DR-Lp(a) does not show the anti-inflammatory capacity seen with HC-Lp(a), but increases REC angiogenesis, and affects PAC differentiation less than HC-Lp(a). These functional differences in Lp(a) in T2DM-related retinopathy are associated with alterations in the lipid composition as compared to healthy conditions.

Up-regulation of miR-192-5p inhibits the ELAVL1/PI3Kδ axis and attenuates microvascular endothelial cell proliferation, migration and angiogenesis in diabetic retinopathy.

Diabetic retinopathy (DR) is a common complication of diabetes mellitus that poses a threat to adults. MicroRNAs (miRNAs) play a key role in DR progression. However, the role and mechanism of miR-192-5p in DR remain unclear. We aimed to investigate the effect of miR-192-5p on cell proliferation, migration and angiogenesis in DR. Expression of miR-192-5p, ELAV-like RNA binding protein 1 (ELAVL1) and phosphoinositide 3-kinase delta (PI3Kδ) in human retinal fibrovascular membrane (FVM) samples and human retinal microvascular endothelial cells (HRMECs) was assessed using RT-qPCR. ELAVL1 and PI3Kδ protein levels were evaluated by Western blot. RIP and dual luciferase reporter assays were performed to confirm the miR-192-5p/ELAVL1/PI3Kδ regulatory networks. Cell proliferation, migration and angiogenesis were assessed by CCK8, transwell and tube formation assays. MiR-192-5p was decreased in FVM samples from DR patients and high glucose (HG)-treated HRMECs. Functionally, overexpressed miR-192-5p inhibited cell proliferation, migration and angiogenesis in HG-treated HRMECs. Mechanically, miR-192-5p directly targeted ELAVL1 and decreased its expression. We further verified that ELAVL1 bound to PI3Kδ and maintained PI3Kδ mRNA stability. Rescue analysis demonstrated that the suppressive effects of HG-treated HRMECs caused by miR-192-5p up-regulation were overturned by overexpressed ELAVL1 or PI3Kδ. MiR-192-5p attenuates DR progression by targeting ELAVL1 and reducing PI3Kδ expression, suggesting a biomarker for the treatment of DR.

Hsa_circ_0000047 targeting miR-6720-5p/CYB5R2 axis alleviates inflammation and angiogenesis in diabetic retinopathy

Context: Diabetic retinopathy (DR) is a common complication of diabetes mellitus (DM). Circular RNAs (circRNAs) act as key regulators of DR development by regulating inflammation and angiogenesis. Objective: This study aimed to elucidate the function and mechanism of hsa_circ_0000047 in DR. Materials and methods: High glucose (HG) was used to induce human retinal microvascular endothelial cells (hRMECs) to construct a DR model in vitro. Qualitative real-time polymerase chain reaction (qRT-PCR) or western blotting were used to detected the levels of hsa_circ_0000047, miR-6720-5p, and CYB5R2 in DR and HG-indeced hRMECs. Cell functional experiments were performed to detect the change of viability, inflammation, migration, invasion, and angiogenesis of HG-induced hRMECs. Besides, the correlation between miR-6720-5p and hsa_circ_0000047/CYB5R2 was confirmed by luciferase assay and Pearson correlation analysis. Results: hsa_circ_0000047 and CYB5R2 were downregulated in DR, whereas miR-6720-5p was upregulated in DR. Cell functional experiments showed that hsa_circ_0000047 overexpression restrained viability, inflammation, migration, invasion, and angiogenesis of HG-induced hRMECs. Regarding mechanism, hsa_circ_0000047 could sponge miR-6720-5p to regulate CYB5R2 expression in hRMECs. Additionally, CYB5R2 knockdown reversed the effects of hsa_circ_0000047 overexpression on HG-induced hRMECs. Conclusion: Our study revealed that hsa_circ_0000047 alleviated inflammation and angiogenesis in HG-induced hRMECs by targeting the miR-6720-5p/CYB5R2 axis, which may be a novel biomarker for DR therapy.

USP14 Regulates ATF2/PIK3CD Axis to Promote Microvascular Endothelial Cell Proliferation, Migration, and Angiogenesis in Diabetic Retinopathy.

Diabetic retinopathy (DR) is one of the leading causes of blindness in diabetic patients. However, the pathogenesis of DR is complex, and no firm conclusions have been drawn so far. It has become a hot spot in ophthalmology research to deeply study the mechanism of DR pathological changes and find effective treatment options. Human retinal microvascular endothelial cells (HRMECs) were induced by high glucose (HG) to construct DR cell model. CCK-8 assay was used to detect the viability of HRMECs. Transwell assay was used to detect the migration ability of HRMECs. Tube formation assay was used to identify the tube formation ability of HRMECs. The expressions of USP14, ATF2 and PIK3CD were detected by Western blot analysis and qRT-PCR assay. Immunoprecipitation (IP) was used to ascertain the relationship of USP14 and ATF2. To explore the regulatory relationship between ATF2 and PIK3CD by dual-luciferase reporter gene assay and Chromatin immunoprecipitation (ChIP) assay. High glucose treatment promoted the proliferation, migration, and tube formation of HRMEC, and the expressions of USP14, ATF2 and PIK3CD were significantly up-regulated. USP14 or ATF2 knockdown inhibited HG-induced HRMECs proliferation, migration, and tube formation. USP14 regulated the expression of ATF2, and ATF2 promoted PIK3CD expression. PIK3CD overexpression attenuated the inhibitory effectiveness of USP14 knockdown on proliferation, migration and tube formation of DR cell model. Here, we revealed that USP14 regulated the ATF2/PIK3CD axis to promote proliferation, migration, and tube formation in HG-induced HRMECs.

The effect of palm oil-derived tocotrienol-rich fraction in preserving normal retinal vascular diameter in streptozotocin-induced diabetic rats.

Angiogenesis in diabetic retinopathy (DR) is associated with increased retinal expression of angiopoietin-2 (Ang-2) and protein kinase C (PKC). Tocotrienol-rich fraction (TRF) has been shown to reduce the expression vascular endothelial growth factor (VEGF) in several experimental models. However, its effect against other angiogenic markers such as Ang-2 and PKC in rat modelof diabetes remains unknown. Therefore, we investigated the effect of TRF on the retinal vascular changes and Ang-2 and PKC expressions in rats with streptozotocin (STZ)-induced DR. Sprague-Dawley rats were divided into normal control rats (N) which received vehicle, and diabetic rats which either received vehicle (DV) or 100mg/kg of TRF (DT). Diabetes was induced with intraperitoneal injection of STZ (60mg/kg body weight). Treatments were given orally, once daily, for 12weeks after confirmation of hyperglycaemia. Fundus photographs were captured at baseline, 6- and 12-week post-STZ injection and average diameter of retinal veins and arteries were measured. At 12-week post-STZ injection, rats were euthanised, and retinae were collected for measurement of Ang-2 and PKC gene and protein expressions. Retinal venous and arterial diameters were significantly greater in DV compared to DT at week 12 post-STZ injection (p < 0.001 and < 0.05, respectively). The vesseldiameter measurements in DT were comparable to N and this effect of TRF was associated with significantly lower Ang-2 and PKC gene and protein expressions compared to DV. Oral TRF reduces the expression of retinal angiogenic markers and preserves the retinalvascular diameter of rats withSTZ-induced DR.

Fisetin Prevents Angiogenesis in Diabetic Retinopathy by Downregulating VEGF.

Diabetic retinopathy (DR) is one of the more serious complications of diabetes. However, the mechanisms involved in DR are complex and still need to be investigated. The beneficial effects of fisetin have been widely reported, but whether it is beneficial in DR is not clear yet. This study was designed to investigate the regulatory role of fisetin in regulating DR and explore the involved mechanism. First, 30 mM glucose was used to establish DR cell model in vitro. Cell counting kit 8 (CCK8) assay was utilized to study the effects of fisetin on cell viability through treating human retinal microvascular endothelial cells (HRMECs) with 25, 50, and 100 μM fisetin. Transwell and wound healing assays were used to detect the function of fisetin on the migration and angiogenesis on HG-induced HRMECs. Finally, OE-VEGF was used as a mimic of VEGF, and western blotting (WB) was used to verify the targeting genes of fisetin. HG induced an increase in cell viability, cell migration, and angiogenesis in HRMECs, whereas fisetin inhibited these enhancements induced by HG through inhibiting VEGF. In conclusion, fisetin prevents angiogenesis in DR by downregulating VEGF.

Inflammation in diabetic retinopathy: possible roles in pathogenesis and potential implications for therapy.

Diabetic retinopathy, characterized as a microangiopathy and neurodegenerative disease, is the leading cause of visual impairment in diabetic patients. Many clinical features observed in diabetic retinopathy, such as capillary occlusion, acellular capillaries and retinal non-perfusion, aggregate retinal ischemia and represent relatively late events in diabetic retinopathy. In fact, retinal microvascular injury is an early event in diabetic retinopathy involving multiple biochemical alterations, and is manifested by changes to the retinal neurovascular unit and its cellular components. Currently, intravitreal anti-vascular endothelial growth factor therapy is the first-line treatment for diabetic macular edema, and benefits the patient by decreasing the edema and improving visual acuity. However, a significant proportion of patients respond poorly to anti-vascular endothelial growth factor treatments, indicating that factors other than vascular endothelial growth factor are involved in the pathogenesis of diabetic macular edema. Accumulating evidence confirms that low-grade inflammation plays a critical role in the pathogenesis and development of diabetic retinopathy as multiple inflammatory factors, such as interleukin-1β, monocyte chemotactic protein-1 and tumor necrosis factor -α, are increased in the vitreous and retina of diabetic retinopathy patients. These inflammatory factors, together with growth factors such as vascular endothelial growth factor, contribute to blood-retinal barrier breakdown, vascular damage and neuroinflammation, as well as pathological angiogenesis in diabetic retinopathy, complicated by diabetic macular edema and proliferative diabetic retinopathy. In addition, retinal cell types including microglia, Müller glia, astrocytes, retinal pigment epithelial cells, and others are activated, to secrete inflammatory mediators, aggravating cell apoptosis and subsequent vascular leakage. New therapies, targeting these inflammatory molecules or related signaling pathways, have the potential to inhibit retinal inflammation and prevent diabetic retinopathy progression. Here, we review the relevant literature to date, summarize the inflammatory mechanisms underlying the pathogenesis of diabetic retinopathy, and propose inflammation-based treatments for diabetic retinopathy and diabetic macular edema.

Thioredoxin-Interacting Protein Inhibited Vascular Endothelial Cell-Induced HREC Angiogenesis Treatment of Diabetic Retinopathy.

Diabetic retinopathy is the most common reason for blindness among employed adults worldwide. Hyperglycemia and the overaccumulation of vascular endothelial growth factor (VEGF) lead to diabetic retinopathy, pathological angiogenesis in diabetic retinopathy, and consequent visual impairment. Expression levels of thioredoxin-interacting protein (TXNIP) substantially increase in retinal endothelial cells in diabetic circumstances. The part of TXNIP in retinal angiogenesis combined with diabetes remains unclear. This study examined the effect of reduced TXNIP expression levels and determined how it affects diabetic retinal angiogenesis. Display of human retinal vascular endothelial cells (HRECs) to moderately high glucose (MHG) encouraged tube formation and cell migration, not cell proliferation. In response to MHG conditions, in HRECs, TXNIP knockdown inhibited the production of reactive oxygen species (ROS), cell migration, tube formation, and the Akt/mTOR activation pathway. In addition, gene silencing of TXNIP decreased the VEGF-triggered angiogenic response in HRECs by preventing activation of both VEGF receptor 2 and the downstream components of the Akt/mTOR pathway signaling. Furthermore, TXNIP knockout mice reduced VEGF-induced or VEGF- and MHG-triggered ex vivo retinal angiogenesis compared to wild-type mice. Finally, our findings revealed that TXNIP knockdown suppressed VEGF- and MHG-triggered angiogenic responses in HRECs and mouse retinas, indicating that TXNIP is a promising therapeutic window against the proliferation of diabetic patients' retinopathy.

Inhibition of KCTD10 Affects Diabetic Retinopathy Progression by Reducing VEGF and Affecting Angiogenesis.

We purposed to evaluate the KCTD10 effects of angiogenesis in diabetic retinopathy (DR). We induced a DR cell model using high glucose (HG) treatment of HRECs and ARPE-19 cells. A DR rat was established by injecting streptozotocin. Small interference RNA targeted KCTD10 (si-KCTD10) was used to mediate KCTD10 inhibition in cell and animal models. The roles of KCTD10 on cell viability, apoptosis, angiogenesis, and related proteins (VEGF and HIF-1α) were observed by RT-qPCR, Western blot, CCK-8 assay, TUNEL staining, tube formation assay, ELISA, and immunohistochemistry assay. KCTD10 expression was upregulated in DR cells and retinal tissue of DR rats. Treatment of the cells with si-KCTD10 increased cell viability and decreased apoptosis and angiogenesis in DR cells. Inhibition of KCTD10 could reduce the expression of VEGF and HIF-1α in DR cells. Furthermore, KCTD10 inhibition reduced VEGF levels in the retinal tissue of DR rats. This work showed that inhibition of KCTD10 relieved angiogenesis in DR.

MicroRNA-150 (miR-150) and Diabetic Retinopathy: Is miR-150 Only a Biomarker or Does It Contribute to Disease Progression?

Diabetic retinopathy (DR) is a chronic disease associated with diabetes mellitus and is a leading cause of visual impairment among the working population in the US. Clinically, DR has been diagnosed and treated as a vascular complication, but it adversely impacts both neural retina and retinal vasculature. Degeneration of retinal neurons and microvasculature manifests in the diabetic retina and early stages of DR. Retinal photoreceptors undergo apoptosis shortly after the onset of diabetes, which contributes to the retinal dysfunction and microvascular complications leading to vision impairment. Chronic inflammation is a hallmark of diabetes and a contributor to cell apoptosis, and retinal photoreceptors are a major source of intraocular inflammation that contributes to vascular abnormalities in diabetes. As the levels of microRNAs (miRs) are changed in the plasma and vitreous of diabetic patients, miRs have been suggested as biomarkers to determine the progression of diabetic ocular diseases, including DR. However, few miRs have been thoroughly investigated as contributors to the pathogenesis of DR. Among these miRs, miR-150 is downregulated in diabetic patients and is an endogenous suppressor of inflammation, apoptosis, and pathological angiogenesis. In this review, how miR-150 and its downstream targets contribute to diabetes-associated retinal degeneration and pathological angiogenesis in DR are discussed. Currently, there is no effective treatment to stop or reverse diabetes-caused neural and vascular degeneration in the retina. Understanding the molecular mechanism of the pathogenesis of DR may shed light for the future development of more effective treatments for DR and other diabetes-associated ocular diseases.

Downregulation of glycoprotein non-metastatic melanoma protein B prevents high glucose-induced angiogenesis in diabetic retinopathy.

Diabetic retinopathy (DR), a microvascular complication characterized by abnormal angiogenesis, is the most common reason for irreversible blindness. Glycoprotein non-metastatic melanoma protein B (GPNMB), as a transmembrane protein, was found to be associated with angiogenesis. This study aims to investigate the role of GPNMB in DR. The levels of GPNMB and Integrin β1 were detected by real-time PCR and western blot and were found to be increased in human retinal microvascular endothelial cells (HRMECs) with high glucose (HG, 25mmol/L) treatment. Knockdown of GPNMB was mediated by lentivirus carrying shRNA targeting GPNMB in vivo and in vitro. Functional experiments, including cell counting kit-8 (CCK-8), scratch, and tube formation assays, showed the anti-proliferative, anti-migrative, and anti-angiogenic roles of GPNMB knockdown in HRMECs using the lentivirus system following HG challenge. Additionally, increased GPNMB levels were detected in the retina of DR rats induced by a single intraperitoneal injection of streptozotocin (60mg/kg) using real-time PCR, western blot, and immunofluorescence assays. Downregulation of GPNMB inhibited the angiogenesis and vascular endothelial growth factor production in the retina of rats with DR. Furthermore, overexpression of Integrin β1 led to increased angiogenesis in DR. Integrin β1 was indicated as a target protein of GPNMB. Upregulated-Integrin β1 restored GPNMB knockdown-induced inhibition of cell viability, migration, and tube formation in HRMECs. In conclusion, we provide evidence for the angiogenic role of GPNMB and demonstrate that silencing GPNMB may represent a therapeutic potential in the treatment of DR.

The mechanism by which crocetin regulates the lncRNA NEAT1/miR-125b-5p/SOX7 molecular axis to inhibit high glucose-induced diabetic retinopathy

Diabetic retinopathy (DR) is a high-incidence microvascular complication with retinal neovascularization that generates irreversible visual impairment. However, the mechanism of DR is unclear and needs to be further explored. To explore the the effects of crocetin on expression of NEAT1 and miR-125b-5p and the proliferation activity, migration ability, and angiogenesis ability of human retinal microvascular endothelial cells (hRMECs), RT-qPCR, CCK-8, Transwell, and tube formation assays were performed. Additionally, Western blot was used to detect the expression of SOX7, VEGFA and CD31. Furthermore, a dual-luciferase reporter gene was used to verify the targeting connection. The DR mouse model was constructed by STZ. The effect of crocetin on DR angiogenesis was detected by hematoxylin-eosin (HE) staining, immunohistochemistry (IHC), retinal digest preparations and Western blot. The results showed that crocetin inhibited the high-glucose (Hg)-induced upregulation of NEAT1 and SOX7 and the downregulation of miR-125b-5p. Crocetin inhibited Hg-induced proliferation, migration and angiogenesis by upregulating the targeted inhibition of SOX7 by miR-125b-5p through the inhibition of NEAT1. To summarize, our study revealed that crocetin has a protective effect on Hg-induced DR by regulating the lncRNA NEAT1/miR-125b-5p/SOX7 molecular axis.

LncRNA MALAT1 aggravates the retinal angiogenesis via miR-320a/HIF-1α axis in diabetic retinopathy

Diabetic retinopathy (DR) is one of the most serious microvascular complications of diabetes and an important cause of blindness in adults. In previous study, we found that miR-320a alleviated the damage of muller cells in DR. In this study, we mainly explored the mechanism of lncRNA MALAT1 on retinal angiogenesis in DR by regulating miR-320a/HIF-1α. The expression of MALAT1 and miR-320a was detected by RT-qPCR, and the expression of HIF-1α was detected by Western blot. The superoxide anion level, invasion, angiogenesis, and vascular permeability of mouse retinal microvascular endothelial cells (MRMECs) co-cultured with muller cells were evaluated by dihydroethidium, transwell, angiogenesis and immunofluorescence assay. In order to analyze the targeting relationship between miR-320a and MALAT1 or HIF-1α, we performed dual luciferase reporter gene, fluorescence in situ hybridization (FISH), RNA immunoprecipitation (RIP) and RNA pulldown experiments. The results should that MALAT1 and HIF-1α were highly expressed and miR-320a was low expressed in high glucose (HG)-induced muller cells, and MALAT1 could competitively bind with HIF-1α. Knocking down miR-320a inhibited MRMECs invasion angiogenesis, and vascular permeability by targeting miR-320a. Overexpression of miR-320a down regulated HIF-1α and inhibited the invasion, angiogenesis, and vascular permeability of MRMECs. In conclusion, MALAT1 inhibits HIF-1α expression and MRMECs angiogenesis in DR through spongy miR-320a.

Lactucaxanthin Regulates the Cascade of Retinal Oxidative Stress, Endoplasmic Reticulum Stress and Inflammatory Signaling in Diabetic Rats

ABSTRACT Purpose The purpose of this study is to investigate the protective mechanism of lactucaxanthin against retinal angiogenesis in diabetic retinopathy. Methods Streptozotocin-induced diabetic rats were orally gavaged with either lactucaxanthin or lutein (n=12/group) for 8 weeks. Serum and retina collected from euthanized rats were subjected to assess oxidative stress, ER stress and inflammatory response. Results Lactucaxanthin administration was found to lower oxidative stress markers (protein carbonylation and lipid peroxidation) by augmenting antioxidant activity expression and ameliorated VEGF-A levels in diabetic group. Likewise, it suppressed the expression of ER stress (ATF4, ATF6, and XBP1), and inflammatory (TNF-α, IL-6, NF-κB, and ICAM-1) markers in diabetic retina. In addition, lactucaxanthin improved glucose tolerance and lipid profile under diabetic condition and suppressed the crosstalk between OS, ER stress, and inflammation. Conclusion Lactucaxanthin could be used as a promising therapeutic bioactive for treating DR condition, and retinal angiogenesis. Expert opinion Limitation of the study includes the sample size and the duration of treatment. Despite these limitations, this study has revealed the potential of lactucaxanthin in treating eye related diabetic complications. To validate the results obtained from this study, clinical study must be performed to understand the relative benefit of lactucaxanthin in DR treatment.

Cyanidin-3-o-glucoside (C3G) inhibits vascular leakage regulated by microglial activation in early diabetic retinopathy and neovascularization in advanced diabetic retinopathy

ABSTRACT Cyanidin-3-O-glucoside (C3G) is a kind of anthocyanin which shows strong anti-inflammation, anti-tumor and anti-oxidant properties. This paper was designed to explore the potential effects of C3G on diabetic retinopathy (DR). C57BL/6 mice were administrated with streptozotocin (STZ) or vehicle control for the establishment of diabetic models. To simulate hyperglycemia and hypoxia, D-glucose (30 mM) and CoCl2 (200 μm/l) were utilized to treat HRECs, respectively. The migration, invasion, inflammation and tube formation abilities of cells were evaluated with the adoption of wound healing, transwell, ELISA and tube formation assays, respectively. Besides, immunofluorescence staining was utilized to detect proliferation and retinal vessels. Evans blue permeation assay were performed to evaluate the vascular leakage in DR mice. Moreover, western blot and qPCR were used to quantify the mRNA and protein expressions of ionized calcium-binding adapter molecule (Iba)-1 and tight junction proteins. Results showed that C3G alleviated the inflammation, microglial activation and angiogenesis in DR mice. Moreover, the proliferation and inflammation of BV2 cells induced by high glucose (HG) were suppressed by C3G. Evans blue permeation assay demonstrated the potency of C3G in attenuating vascular leakage. In addition, C3G suppressed the migration, invasion and angiogenesis of human retinal endothelial cells (HRECs) DR model in vitro. By confirming the role of C3G in inhibiting vascular leakage regulated by microglia activation in early DR and angiogenesis in advanced DR, this study pointed out the potential of C3G as a therapeutic drug for DR management.

A novel regulatory network of linc00174/miR-150-5p/VEGFA modulates pathological angiogenesis in diabetic retinopathy.

Diabetic retinopathy (DR) has been regarded as a sight-threatening vascular complication of diabetes mellitus. Accumulating evidence has identified the involvement of long non-coding RNAs (lncRNAs) in DR pathogenesis. We aim to investigate the role and underlying mechanism of linc00174 in the DR process. Samples of human vitreous humour from proliferative DR and non-diabetic individuals were collected to examine the levels of linc00174. Human retinal microvascular endothelial cells (HRMECs) exposed with high glucose (HG) were employed to simulate the pathological statues of DR. Short hairpin RNA specifically targeting linc00174 was applied. CCK-8, transwell, and matrigel tube formation were performed to evaluate cell proliferation, migration, and angiogenesis. Bioinformatics analysis and luciferase reporter assay were conducted to verify the linc00174/miR-150-5p/vascular endothelial growth factor A (VEGFA) regulatory network. Western blotting was employed to determine the expression of VEGFA. Linc00174 was significantly elevated in patients with DR, as well as HG-stimulated HRMECs, of which knockdown repressed HG-induced proliferation, migration, and angiogenesis. miR-150-5p was identified as a downstream effector to be involved in linc00174-mediated protective effects. miR-150-5p directly bound to the 3' untranslated region of VEGFA. The linc00174/miR-150-5p/VEGFA axis was confirmed in retinal vascular dysfunction. The linc00174 deteriorates diabetic retinal microangiopathy via regulating miR-150-5p/VEGFA pathway, indicating a novel therapeutic target for DR treatment.

The Long Non-Coding RNA HOTAIR Is a Critical Epigenetic Mediator of Angiogenesis in Diabetic Retinopathy.

PurposeDiabetic retinopathy (DR) remains a pressing issue worldwide. Abnormal angiogenesis is a distinct vascular lesion in DR, and research has established that vascular endothelial growth factor A (VEGF-A) is a primary mediator of such changes. However, limitations in current anti-VEGF therapies suggest that our understanding of molecular networks underlying ocular angiogenesis remains far from complete. Based on our long non-coding RNA (lncRNA) array analyses, HOX antisense intergenic RNA (HOTAIR) was identified as one of the top upregulated lncRNAs in high glucose-cultured human retinal endothelial cells (HRECs). Given the well-documented roles of HOTAIR in cancer, no studies have examined the epigenetic implications of HOTAIR in DR, and we investigated such relationships herein.MethodsWe used HRECs exposed to various glucose concentrations and epigenetic modulators to examine HOTAIR, angiogenic, and DR-related molecular markers. Oxidative stress, angiogenesis, and mitochondrial dysfunction were assessed. Retinal tissues of diabetic rodents and the vitreous humor and serum of patients with proliferative DR were also investigated.ResultsHyperglycemia significantly augmented HOTAIR expression in HRECs and promoted angiogenesis, oxidative damage, and mitochondrial aberrations. Similarly, vitreous humor and serum from proliferative DR patients and retinas from diabetic animals demonstrated increased HOTAIR expression compared to non-diabetic controls. HOTAIR knockdown protected against glucose-induced increases of angiogenic and diabetes-associated molecules in the retina. Mechanistically, we showed that HOTAIR exerts its capabilities by preventing oxidative stress and modulating epigenetic pathways involving histone methylation, histone acetylation, DNA methylation, and transcription factors.ConclusionsOur findings suggest that HOTAIR is a critical lncRNA in the pathogenesis of DR and may potentially be important for diagnostic and therapeutic targeting.

Lactucaxanthin protects retinal pigment epithelium from hyperglycemia-regulated hypoxia/ER stress/VEGF pathway mediated angiogenesis in ARPE-19 cell and rat model

Hyperglycemia mediated perturbations in biochemical pathways induce angiogenesis in diabetic retinopathy (DR) pathogenesis. The present study aimed to investigate the protective effects of lactucaxanthin, a predominant lettuce carotenoid, on hyperglycemia-mediated activation of angiogenesis in vitro and in vivo diabetic model. ARPE-19 cells cultured in 30 mM glucose concentration were treated with lactucaxanthin (5 μM and 10 μM) for 48 h. They were assessed for antioxidant enzyme activity, mitochondrial membrane potential, reactive oxygen species, and cell migration. In the animal experiment, streptozotocin-induced diabetic male Wistar rats were gavaged with lactucaxanthin (200 μM) for 8 weeks. Parameters like animal weight gain, feed intake, water intake, urine output, and fasting blood glucose level were monitored. In both models, lutein-treated groups were considered as a positive control. Hyperglycemia-mediated angiogenic marker expressions in ARPE-19 and retina of diabetic rats were quantified through the western blot technique. Expression of hypoxia, endoplasmic reticulum stress markers, and vascular endothelial growth factor were found to be augmented in the hyperglycemia group compared to control (P < 0.05). Hyperglycemia plays a crucial role in increasing cellular migration and reactive oxygen species besides disrupting tight junction protein. Compared to lutein, lactucaxanthin aids retinal pigment epithelium (RPE) function from hyperglycemia-induced stress conditions via downregulating angiogenesis markers expression. Lactucaxanthin potentiality observed in protecting tight junction protein expression via modulating reactive oxygen species found to conserve RPE integrity. Results demonstrate that lactucaxanthin exhibits robust anti-angiogenic activity for the first time and, therefore, would be useful as an alternative therapy to prevent or delay DR progression.

MiR-7a Targets Insulin Receptor Substrate-2 Gene and Suppresses Viability and Invasion of Cells in Diabetic Retinopathy Mice via PI3K-Akt-VEGF Pathway.

IntroductionDiabetic retinopathy (DR) is one of the major leading causes for vision loss globally. Current study illustrates the role of miR-7a in DR.Material and MethodsRetinal pericytes (RPs) and Endothelial cells (ECs) were isolated from mouse model of DR. qRT-PCR was done for expression of miR-7a and target gene mRNA, Western blot for protein expression. Identification of miR-7a target gene was done by TargetScan and Luciferase assay. Cell viability and invasion was done by MTT and Transwell chamber assay.ResultsThe expression of miR-7a was down-regulated whereas level of IRS-2 was unregulated in isolated RPs and ECs. Luciferase assay suggested correlation between miR-7a and IRS-2, over-expression of miR-7a using a mimic resulted in suppression in viability and invasion capacity of RPs and ECs and inhibited the protein levels of PI3K/Akt cascade and IRS-2, and however the inhibitor reversed them respectively. Transfection of siRNA targeting IRS-2 caused alteration in miR-7a mediated changes in ECs suggesting that miR-7a may decrease angiogenesis in DR by inhibiting the levels of IRS-2.ConclusionmiR-7a suppresses PI3K/Akt cascade via targeting IRS-2, thus decreasing the viability and invasion capacity of RPs and ECs, suggesting an interesting treatment target for DR.

ASK1/p38‑mediated NLRP3 inflammasome signaling pathway contributes to aberrant retinal angiogenesis in diabetic retinopathy.

Diabetic retinopathy (DR) is the leading cause of blindness among the working-age population in several countries. Despite the available treatments, some patients are diagnosed at the late stages of the disease when treatment is more difficult. Hence, it is crucial that novel targets are identified in order to improve the clinical therapy of DR. In the present study, an animal model of DR and a cell model using primary human retinal microvascular endothelial cells exposed to high glucose were constructed to examine the association between apoptosis signal-regulating kinase 1 (ASK1)/p38 and NLR family pyrin domain containing 3 (NLRP3) in DR. The results revealed that DR induced inflammatory response and micro-vascular cell proliferation. NLRP3 contributed to DR-mediated inflammatory development and progression, which promoted the expression of inflammatory-related cytokines. In addition, NLRP3 promoted the tube formation of retinal microvascular endothelial cells and angiogenesis. Moreover, further research indicated that the NLRP3-mediated aberrant retinal angiogenesis in DR was regulated by ASK1 and p38. It was thus suggested that ASK1/p38 may be novel target for the treatment of DR.