Effects of miRNA-200b on the development of diabetic retinopathy by targeting VEGFA gene

Post-stroke cognitive impairment: exploring molecular mechanisms and omics biomarkers for early identification and intervention

Post-stroke cognitive impairment (PSCI) is a major stroke consequence that has a severe impact on patients' quality of life and survival rate. For this reason, it is especially crucial to identify and intervene early in high-risk groups during the acute phase of stroke. Currently, there are no reliable and efficient techniques for the early diagnosis, appropriate evaluation, or prognostication of PSCI. Instead, plenty of biomarkers in stroke patients have progressively been linked to cognitive impairment in recent years. High-throughput omics techniques that generate large amounts of data and process it to a high quality have been used to screen and identify biomarkers of PSCI in order to investigate the molecular mechanisms of the disease. These techniques include metabolomics, which explores dynamic changes in the organism, gut microbiomics, which studies host-microbe interactions, genomics, which elucidates deeper disease mechanisms, transcriptomics and proteomics, which describe gene expression and regulation. We looked through electronic databases like PubMed, the Cochrane Library, Embase, Web of Science, and common databases for each omics to find biomarkers that might be connected to the pathophysiology of PSCI. As all, we found 34 studies: 14 in the field of metabolomics, 5 in the field of gut microbiomics, 5 in the field of genomics, 4 in the field of transcriptomics, and 7 in the field of proteomics. We discovered that neuroinflammation, oxidative stress, and atherosclerosis may be the primary causes of PSCI development, and that metabolomics may play a role in the molecular mechanisms of PSCI. In this study, we summarized the existing issues across omics technologies and discuss the latest discoveries of PSCI biomarkers in the context of omics, with the goal of investigating the molecular causes of post-stroke cognitive impairment. We also discuss the potential therapeutic utility of omics platforms for PSCI mechanisms, diagnosis, and intervention in order to promote the area's advancement towards precision PSCI treatment.

Identifying the stability of housekeeping genes to be used for the quantitative real-time PCR normalization in retinal tissue of streptozotocin-induced diabetic rats

AIM

To investigate the stability of the seven housekeeping genes: beta-actin (ActB), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), 18s ribosomal unit 5 (18s), cyclophilin A (CycA), hypoxanthine-guanine phosphoribosyl transferase (HPRT), ribosomal protein large P0 (36B4) and terminal uridylyl transferase 1 (U6) in the diabetic retinal tissue of rat model.

METHODS

The expression of these seven genes in rat retinal tissues was determined using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) in two groups; normal control rats and streptozotocin-induced diabetic rats. The stability analysis of gene expression was investigated using geNorm, NormFinder, BestKeeper, and comparative delta-Ct (ΔCt) algorithms.

RESULTS

The 36B4 gene was stably expressed in the retinal tissues of normal control animals; however, it was less stable in diabetic retinas. The 18s gene was expressed consistently in both normal control and diabetic rats' retinal tissue. That this gene was the best reference for data normalisation in RT-qPCR studies that used the retinal tissue of streptozotocin-induced diabetic rats. Furthermore, there was no ideal gene stably expressed for use in all experimental settings.

CONCLUSION

Identifying relevant genes is a need for achieving RT-qPCR validity and reliability and must be appropriately achieved based on a specific experimental setting.

Transthyretin-Regulated Diabetic Retinopathy Through the VEGFA/PI3K/AKT Pathway

Purpose

Transthyretin (TTR) plays a regulatory role in a variety of diabetes-related diseases. The objective of this work was to probe whether TTR affects diabetic retinopathy (DR) through the VEGFA/PI3K/AKT pathway.

Methods

High glucose (HG, 25 mM) was used to treat human retinal microvascular endothelial cells (hRMECs) and C57BL/6J mice were intraperitoneally injected with STZ (50 mg/kg) to construct a DR model. In vitro, the effect of TTR on DR was evaluated by measuring hRMEC proliferation, migration, and angiogenesis. The changes in retinal tissue were observed by hematoxylin and eosin staining in vivo. ELISA, immunohistochemistry, and immunofluorescence staining were used to measure VEGFA or CD31 levels. The levels of all proteins were evaluated through Western blot.

Results

The increase of proliferation, migration, and angiogenesis and decrease of apoptosis in hRMECs caused by HG were notably reversed by TTR. TTR greatly impeded HG-raised VEGFA, PI3K p-p85, and p-AKT in hRMECs. Inhibition of TTR further exacerbated the effect of HG-induced hRMECs. Inhibition of VEGFA reversed the effect of HG-induced hRMECs. VEGFA neutralized the function of TTR on cell proliferation, apoptosis, migration, and angiogenesis in HG-triggered hRMECs. It was further confirmed in vivo that TTR can alleviate the occurrence of DR in diabetic mice models.

Conclusions

TTR significantly restrained the progression of DR via molecular modulation of the VEGFA/PI3K/AKT axis.

Advances and Perspectives in Relation to the Molecular Basis of Diabetic Retinopathy-A Review

Diabetes mellitus (DM) is a growing problem nowadays, and diabetic retinopathy (DR) is its predominant complication. Currently, DR diagnosis primarily relies on fundoscopic examination; however, novel biomarkers may facilitate that process and make it widely available. In this current review, we delve into the intricate roles of various factors and mechanisms in DR development, progression, prediction, and their association with therapeutic approaches linked to the underlying pathogenic pathways. Specifically, we focus on advanced glycation end products, vascular endothelial growth factor (VEGF), asymmetric dimethylarginine, endothelin-1, and the epigenetic regulation mediated by microRNAs (miRNAs) in the context of DR.

circFTO upregulates transforming growth factor-alpha through sponging miR-148a-3p to regulate high glucose-induced ARPE-19 cells injury

Diabetic retinopathy (DR) is one of the most common retinal microvascular diseases in diabetic patients. Therefore, elucidating the underlying molecular mechanism of DR is of great significance for its clinical treatment. This study explores the effects of the upregulated circFTO in DR patients in terms of cell apoptosis and viability. Several molecular assays are employed to explore these molecular mechanistic aspects, such as luciferase reporter, RNA pull-down, RT-qPCR, Western blot, and ELISA assays. miR-148a-3p is downregulated in DR patients. The expression of circFTO promoted ARPE-19 cells apoptosis and inhibited proliferation, reflecting the regulatory effect of circFTO/miR-148a-3p on retinal epithelial cells injury. In addition, the absence of circFTO could reduce ARPE-19 cells injury caused by HG by inhibiting oxidative stress and inflammation. Further, the investigations at the molecular level showed that circFTO could regulate the level of miR-148a-3p and TGFA in vitro. As the molecular sponge of miR-148a-3p, circFTO regulated cell viability and apoptosis and promoted the progression of DR through regulating the expression of TGFA. Together, this study provides new targets and markers for early diagnosis and therapy of DR.

Adiponectin Ameliorates Hyperglycemia-Induced Retinal Endothelial Dysfunction, Highlighting Pathways, Regulators, and Networks

Background

The pathophysiology of diabetic retinopathy (DR) is multifaced. A low level of circulating adiponectin (APN) in type 2 diabetes is associated with microvasculature complications, and its role in the evolution of DR is complex.

Aim

This study is designed to explore the potential impact of APN in the pathogenesis of DR, linking the changes in cellular and biological processes with the pathways, networks, and regulators involved in its actions.

Methods

Human microvascular retinal endothelial cells (HMRECs) were exposed to 30mM glucose (HG) and treated with globular adiponectin (30μg/mL) for 24 hours. The cells were evaluated for reactive oxidative stress (ROS) and apoptosis. RT-PCR profile arrays were utilized to evaluate the profile of genes involved in endothelial functions, angiogenesis, extracellular matrix, and adhesion molecules for hyperglycemic HMRECs treated with adiponectin. In addition, the barrier function, leukocyte migration, and angiogenesis were evaluated. The differential expressed genes (DEGs) were outlined, and bioinformatic analysis was applied.

Results

Adiponectin suppresses ROS production and apoptosis in HMRECs under HG conditions. Adiponectin improved migration and barrier functions in hyperglycemic cells. The bioinformatic analysis highlighted that the signaling pathways of integrin, HMGB1, and p38 AMPK, are mainly involved in the actions of APN on HMRECs. APN significantly affects molecular functions, including the adhesion of cells, chemotaxis, migration of WBCs, and angiogenesis. STAT3, NFKB, IKBKB, and mir-8 are the top upstream regulators, which affect the expressions of the genes of the data set, while TNF and TGFB1 are the top regulators.

Conclusion

Adiponectin significantly counteracts hyperglycemia at various cellular and molecular levels, reducing its impact on the pathophysiological progression towards DR in vitro using HMRECs. Adiponectin ameliorates inflammatory response, oxidative stress, and endothelial barrier dysfunction using a causal network of NFBk complex, TNF, and HMGB1 and integrin pathways.

Decreased Levels of miR-126 and miR-132 in Plasma and Vitreous Humor of Non-Proliferative Diabetic Retinopathy Among Subjects with Type-2 Diabetes Mellitus

PURPOSE

Diabetic retinopathy (DR), the leading cause of blindness among working adults, is an urgent public health problem as diabetes mellitus (DM) is increasing at an alarming rate. Hyperglycemia-induced endothelial dysfunction is the principal contributing factor leading to the development of microangiopathy. Altered levels of microRNA (miR), the negative regulator of protein-coding genes, have been observed and considered to be markers for DR. Present study aimed to find out whether miR levels in plasma could be effective biomarkers to differentiate between type 2 diabetes mellitus (T2DM) with non-proliferative retinopathy (NPDR) from T2DM with no-DR (DNR).

METHODS

We recruited 50 T2DM subjects comprising 31 NPDR and 19 DNR individuals. Surrogate markers of systemic oxidative stress and vascular endothelial growth factor (VEGF) were measured in plasma. Levels of miR-126 and miR-132 were determined in plasma and vitreous fluid using real-time PCR.

RESULTS

We observed that levels of miR-126 and miR-132 were decreased in NPDR subjects in comparison to DNR. Plasma levels of miRs were inversely correlated with secreted levels of VEGF and oxidative stress marker. The levels of these miRs showed discriminating ability between NPDR and DNR.

CONCLUSION

Circulating miRs 126 and 132 in plasma or vitreous may serve as biomarkers for early diabetic retinopathy risk prediction, provided validated in a larger cohort and other forms of retinal vasculopathy or retinopathy in the future.

Dissecting the Pathogenesis of Diabetic Retinopathy Based on the Biological ceRNA Network and Genome Variation Disturbance

Background

Diabetic retinopathy (DR) is the most important manifestation of diabetic microangiopathy. It is essential to explore the gene regulatory relationship and genomic variation disturbance of biological networks in DR progression.

Methods

In this study, we constructed a comprehensive lncRNA-mRNA ceRNA network of DR procession (CLMN) and explored its topological characteristics.

Results

Modular and functional analysis indicated that the organization of CLMN performed fundamental and specific functions in diabetes and DR pathology. The differential expression of hub ceRNA nodes and positive correlation reveals the highly connected ceRNA regulation and important roles in the regulating of DR pathology. A large proportion of SNPs in the TFBS, DHS, and enhancer regions of lncRNAs will affect lncRNA transcription and further cause expression variation. Some SNPs were found to disrupt the lncRNA functional elements such as miRNA target binding sites. These results indicate the complex nature of genotypic effects in the disturbing of CLMN and further contribute to gene expression variation and different disease phenotypes.

Conclusion

The identification of individual genomic variations and analysis of biological network disturbance by these genomic variations will help provide more personalized treatment plans and promote the development of precision medicine for DR.

MicroRNA-93-5p participates in type 2 diabetic retinopathy through targeting Sirt1

OBJECTIVE

To investigate the role of miR-93-5p in rats with type 2 diabetic retinopathy (DR) through targeting Sirt1.

METHODS

The targeting correlation between miR-93-5p and Sirt1 was validated by dual-luciferase reporter gene assay. Type 2 diabetes mellitus (T2DM) rat models were received intravitreal injection of antagomir NC (negative control), miR-93-5p antagomir, miR-93-5p agomir and/or recombinant Sirt1, followed by observation of pathological changes in retina via HE staining. Besides, retinal vascular permeability was determined by fluorescein isothiocyanate-bovine serum albumin (FITC-BSA), while the retinal vasculature was observed through retinal trypsin digestion. Expression of miR-93-5p and Sirt1 was measured by qRT-PCR and Western blotting, while the levels of VEGF, proinflammatory cytokines and anti-oxidative indicators were determined using corresponding kits.

RESULTS

MiR-93-5p could target Sirt1 as analyzed by the luciferase reporter gene assay. Rats in the T2DM group presented the up-regulation of miR-93-5p and down-regulation of Sirt1 in the retina, and miR-93-5p inhibition could up-regulate Sirt1 expression in the T2DM rats. Recombinant Sirt1 decreased retinal vascular permeability and acellular capillaries with improved pathological changes in retina from T2DM rats, which was abolished by miR-93-5p agomir. Moreover, miR-93-5p inhibition or Sirt1 overexpression decreased the levels of VEGF and proinflammatory cytokines while enhancing the activity of anti-oxidative indicators. However, indicators above had no significant differences between T2DM group and T2DM + agomir + Sirt1 group.

CONCLUSION

MiR-93-5p, via targeting Sirt1, could affect the vascular permeability and acellular capillaries and mitigate the inflammation and oxidative stress in the retinas, which may play a critical role in DR.

Bone marrow mesenchymal stem cells-induced exosomal microRNA-486-3p protects against diabetic retinopathy through TLR4/NF-κB axis repression

AIM

Diabetic retinopathy (DR) is a chronic disease causing health and economic burdens on individuals and society. Thus, this study is conducted to figure out the mechanisms of bone marrow mesenchymal stem cells (BMSCs)-induced exosomal microRNA-486-3p (miR-486-3p) in DR.

METHODS

The putative miR-486-3p binding sites to 3'untranslated region of Toll-like receptor 4 (TLR4) was verified by luciferase reporter assay. High glucose (HG)-treated Muller cells were transfected with miR-486-3p or TLR4-related oligonucleotides and plasmids to explore theirs functions in DR. Additionally, HG-treated Muller cells were co-cultured with BMSC-derived exosomes, exosomes collected from BMSCs that had been transfected with miR-486-3p or TLR4-related oligonucleotides and plasmids to explore their functions in DR. MiR-486-3p, TLR4 and nuclear factor-kappaB (NF-κB) expression, angiogenesis-related factors, oxidative stress factors, viability and apoptosis in HG-treated Muller cells were detected by RT-qPCR, western blot analysis, ELISA, MTT assay and flow cytometry, respectively.

RESULTS

MiR-486-3p was poorly expressed while TLR4 and NF-κB were highly expressed in HG-treated Muller cells. TLR4 was a target of miR-486-3p. Upregulating miR-486-3p or down-regulating TLR4 inhibited oxidative stress, inflammation and apoptosis, and promoted proliferation of HG-treated Muller cells. Meanwhile, BMSC-derived exosomes inhibited oxidative stress, inflammation and apoptosis, and promoted proliferation of HG-treated Muller cells. Restoring miR-486-3p further enhanced, while up-regulating TLR4 reversed, the improvement of exosomes treatment.

CONCLUSION

Our study highlights that up-regulation of miR-486-3p induced by BMSC-derived exosomes played a protective role in DR mice via TLR4/NF-κB axis repression.

The Role of microRNAs in the Development of Type 2 Diabetes Complications

MicroRNAs represent a class of small (19-25 nucleotides) single-strand pieces of RNA that are noncoding ones. They are synthesized by RNA polymerase II from transcripts that fold back on themselves. They mostly act as gene regulatory agents that pair with complementary sequences on mRNA and produce silencing complexes, which, in turn, suppress coding genes at a post-transcriptional level. There is now evidence that microRNAs may affect insulin secretion or insulin action, as they can alter pancreatic beta cells development, insulin production, as well as insulin signaling. Any molecular disorder that affects these pathways can deteriorate insulin resistance and lead to type 2 diabetes mellitus (T2DM) onset. Furthermore, the expression of several microRNAs is up- or down-regulated in the presence of diabetic microvascular complications (i.e., peripheral neuropathy, nephropathy, retinopathy, foot ulcers), as well as in patients with coronary heart disease, stroke, and peripheral artery disease. However, more evidence is needed, specifically regarding T2DM patients, to establish the use of such microRNAs as diagnostical biomarkers or therapeutic targets in daily practice.

The effects of chronic hypoxia on the endocrine-related parameters in elderly rats with type 2 diabetes mellitus

OBJECTIVE

This study aimed to investigate the effects of chronic hypoxia on the endocrine-related parameters in elderly rats with type 2 diabetes mellitus.

METHODS

Sixty, 55-week-old, female SD rats were studied, among which 20 were randomly divided into a blank control group (the BCG), and 40 were intraperitoneally injected with low-dose streptozotocin (STZ) for modeling and divided into a model control group (the MCG, n=20) and a hypoxic group (the HG, n=20). The BCG and the MCG were fed routinely under normoxia, while the HG was fed in the hypoxic environment of an OxyCycler Model A84XO hypoxic chamber. After 12 weeks of intervention, the body weights, the fasting blood glucose (FBG) levels, the fasting insulin (FINS) levels, the blood lipid metabolism levels, the bone densities, the fresh weights of the femurs, the biomechanical properties of the femurs, the inflammatory factor levels, the H&E staining of the liver tissue, and the oil red O staining were compared.

RESULTS

The increases in weight gain and the FBG and FINS levels in the HG were lower than the corresponding levels in the MCG and were higher than the levels in the BCG (P<0.05). The TC, TG, and LDL-C levels in the HG were lower than they were in the MCG and higher than they were in the BCG (P<0.05). The bone density and fresh weight of the femurs at 12 weeks after the intervention in the HG were higher than they were in the MCG and lower than they were in the BCG (P<0.05). The maximum stress, maximum load, fracture load, and elastic modulus in the HG were higher than they were in the MCG and lower than they were in the BCG (P<0.05). The TNF-α, IL-6, PAI-1, and CRP levels in the HG were lower than they were in the MCG and higher than they were in the BCG (P<0.05).

CONCLUSION

Chronic hypoxia can improve the endocrine parameters and insulin resistance, improve the insulin sensitivity and the femoral biomechanics, reduce the inflammatory factors levels, and improve the glucose and lipid metabolism levels and liver function in elderly rats with type 2 diabetes.

Down-regulating NEAT1 inhibited the viability and vasculogenic mimicry formation of sinonasal squamous cell carcinoma cells via miR-195-5p/VEGFA axis

The role of long non-coding RNA nuclear-enriched abundant transcript 1 (lncRNA NEAT1) in sinonasal squamous cell carcinoma (SNSCC) remained obscure. Target genes and potential binding sites of NEAT1, microRNA (miR)-195-5p and VEGFA were predicted using StarBase and TargetScan, and confirmed by dual-luciferase reporter assay. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expressions of NEAT1, vascular endothelial growth factor A (VEGFA) and miR-195-5p. Pearson's correlation analysis of NEAT1, miR-195-5p and VEGFA was conducted. Cell viability, apoptosis and tube formation capability were assessed by MTT assay, flow cytometry and capillary-like tube formation assay, respectively. Expressions of VEGFA and proteins related to the phosphatidylinositide 3-kinase/Protein Kinase B (PI3K/AKT) pathway were measured by Western blot. In SNSCC tissues and cells, the expressions of NEAT1 and VEGFA were up-regulated while the expression of miR-195-5p was down-regulated, and NEAT1 was negatively correlated with miR-195-5p yet positively correlated with VEGFA. Overexpressed VEGFA promoted the viability and capillary-like tube formation of SNSCC cells yet suppressed their apoptosis, while silencing VEGFA led to the opposite results. MiR-195-5p could bind to NEAT1, and down-regulating miR-195-5p reversed the effects of silencing NEAT1 on the expressions of NEAT1 and miR-195-5p, cell viability, apoptosis and capillary-like tube formation as well as PI3K/AKT pathway activation. VEGFA was the target of miR-195-5p, and overexpressed VEGFA reversed the effects of miR-195-5p. Down-regulating NEAT1 inhibited the viability and vasculogenic mimicry formation of SNSCC cells yet promoted their apoptosis via the miR-195-5p/VEGFA axis, providing a possible therapeutic target for SNSCC treatment.

miR-200-3p suppresses cell proliferation and reduces apoptosis in diabetic retinopathy via blocking the TGF-β2/Smad pathway

Increasing evidence has shown that microRNAs (miRNAs) play an important role in the pathogenesis of diabetic retinopathy (DR). However, the role and mechanism of miRNA in regulating high glucose (HG)-induced ARPE-19 cell injury are still not well understood. The present study aimed to investigate the effects of miR-200a-3p on DR progression and reveal the underlying mechanisms of their effects. In the present study, we observed that miR-200a-3p was significantly decreased, while transforming growth factor-β2 (TGF-β2) expression was up-regulated in ARPE-19 cells treated with HG and retina tissues of DR rats. Subsequently, overexpression of miR-200a-3p significantly promoted cell proliferation, reduced apoptosis, as well as inhibited the levels of inflammatory cytokines secreted, matrix metalloprotease 2/9 (MMP2/9), and vascular endothelial growth factor (VEGF) in HG-injured ARPE-19 cells. Moreover, miR-200a-3p was proved to target TGF-β2 mRNA by binding to its 3′ untranslated region (3′UTR) using a luciferase reporter assay. Mechanistically, overexpression of miR-200a-3p reduced HG-induced ARPE-19 cell injury and reduced inflammatory cytokines secreted, as well as down-regulated the expression of VEGF via inactivation of the TGF-β2/Smad pathway in vitro. In vivo experiments, up-regulation of miR-200a-3p ameliorated retinal neovascularization and inflammation of DR rats. In conclusion, our findings demonstrated that miR-200a-3p-elevated prevented DR progression by blocking the TGF-β2/Smad pathway, providing a new therapeutic biomarker for DR treatment in the clinic.

Recent Highlights of Research on miRNAs as Early Potential Biomarkers for Cardiovascular Complications of Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) and its complications pose a serious threat to the life and health of patients around the world. The most dangerous complications of this disease are vascular complications. Microvascular complications of T2DM include retinopathy, nephropathy, and neuropathy. In turn, macrovascular complications include coronary artery disease, peripheral artery disease, and cerebrovascular disease. The currently used diagnostic methods do not ensure detection of the disease at an early stage, and they also do not predict the risk of developing specific complications. MicroRNAs (miRNAs) are small, endogenous, noncoding molecules that are involved in key processes, such as cell proliferation, differentiation, and apoptosis. Recent research has assigned them an important role as potential biomarkers for detecting complications related to diabetes. We suggest that utilizing miRNAs can be a routine approach for early diagnosis and prognosis of diseases and may enable the development of better therapeutic approaches. In this paper, we conduct a review of the latest reports demonstrating the usefulness of miRNAs as biomarkers in the vascular complications of T2DM.

Human umbilical cord mesenchymal stem cells-derived exosomal microRNA-17-3p ameliorates inflammatory reaction and antioxidant injury of mice with diabetic retinopathy via targeting STAT1

BACKGROUND

Accumulating evidence has reported the role of microRNA (miR) on diabetic retinopathy (DR). Thus, the aim of the study was to investigate the effect of exosomal miR-17-3p targeting signal transducer and activator of transcription 1 (STAT1) on inflammatory reaction and antioxidant injury of DR mice.

METHODS

A mouse diabetes model was established and injected with miR-17-3p-containing human umbilical cord mesenchymal stem cells (hucMSCs)-derived exosomes to ascertain the role of exosomal miR-17-3p. The blood glucose, glycosylated hemoglobin (HbAlc), weight, hemoglobin (Hb) content, inflammatory factors, oxidative stress factors, vascular endothelial growth factor (VEGF), apoptosis index and glutamine synthetase (GS) level in serum and/or retinal tissues of DR mice were measured. miR-17-3p and STAT1 expression in retinal tissues as well as the target relationship between miR-17-3p and STAT1 were tested.

RESULTS

miR-17-3p decreased and STAT1 increased in retinal tissues of DR mice, and STAT1 was the target gene of miR-17-3p. Injection of up-regulated exosomal miR-17-3p reduced the blood glucose and HbAlc, increased the weight, Hb content and GS level, decreased contents of inflammatory factors and VEGF, alleviated oxidative injury, and inhibited retinal cell apoptosis in DR mice through inhibiting STAT1.

CONCLUSION

Functional studies reveal that hucMSCs-derived exosomes shuffle miR-17-3p to ameliorate inflammatory reaction and oxidative injury of DR mice via targeting STAT1.

Luo Tong Formula Alleviates Diabetic Retinopathy in Rats Through Micro-200b Target

Aim: Diabetic retinopathy (DR) is a serious complication of diabetes (DM). Luo Tong formula (LTF) exerts protective effects against DR in rats, but its underlying mechanism remains unknown. Methods: Sprague-Dawley rats injected with streptozotocin (STZ) were used as an experimental diabetes model. LTF or calcium dobesilate (CaD) was administered to diabetic rats via gastric gavage. After the 12 weeks of treatment, blood and tissue samples were collected to determine serum glucose and retinal structure. Blood samples were collected for blood glucose and hemorheology analysis. Gene or protein expression levels were evaluated by immunohistochemistry, western blotting and/or quantitative real-time polymerase chain reaction (PCR). Results: DM rats exhibits significantly increased blood retinal-barrier (BRB) breakdown and VEGF/VEGFR expression in the retina, and decreased miR-200b and tight junction ZO-1/Occludin/ Claudin-5 genes expression, as well as Ang-1/Tie-2 expressions in the retina compared to normal control group. LTF treatment significantly moderated histological abnormalities in diabetic rats, independent of blood glucose level; improved some hemorrheological parameters; decreased the expressions of VEGF/VEGFR and BRB breakdown, significantly increased PEDF and tight junction proteins ZO-1/Occludin, as well as increased retinal miR-200b expression compared to non-treatment diabetic rats. Moreover, LTF prevented the reduction in Ang-1/Tie-2 expression. Conclusions: LTF treatment ameliorated DR through its repair vascular and attenuate vascular leakage. A mechanism involving miR-200b may contribute to benefit effects.

MicroRNA-15b Targets VEGF and Inhibits Angiogenesis in Proliferative Diabetic Retinopathy

BACKGROUND

Vascular endothelial growth factor (VEGF)-induced angiogenesis is a critical compensatory response to microvascular rarefaction in the diabetic retina that contributes to proliferative diabetic retinopathy (PDR). In this study, we sought to determine the role of specific micro ribonucleic acids (RNAs) (miRs) associated with VEGF in patients with PDR pathology.

METHODS

RNA sequencing was employed to detect differentially circulating miR associated with VEGF in patients with diabetes mellitus (DM), nonproliferative diabetic retinopathy (NPDR) and PDR. Quantitative real-time polymerase chain reaction was performed to measure the concentration of miR-15b in the serum of patients with DM (n = 115), NPDR (n = 47), or PDR (n = 76). The effects of miR-15b on DR and regulation of VEGF and endothelial cell function were also characterized.

RESULTS

We demonstrated that circulating miR-15b was directly associated with VEGF compared with other miRs in patients with PDR. We found a significant inverse relationship between low levels of miR-15b and high levels of VEGF in patients with PDR when compared with the DM or NPDR groups. We found that miR-15b regulates the expression of VEGF by targeting the 3'-untranslated regions to inhibit its transcription. Similarly, overexpression of miR-15b suppressed vascular abnormalities in vivo in diabetic GK rats, inhibiting endothelial tube formation and VEGF expression.

CONCLUSION

Circulating miR-15b is associated with PDR and may be targeted to regulate VEGF expression and angiogenesis.

Overexpression of histone deacetylase SIRT1 exerts an antiangiogenic role in diabetic retinopathy via miR-20a elevation and YAP/HIF1α/VEGFA depletion

As a basic member of the Class III histone deacetylases, SIRT1 has been implicated in the occurrence and progression of diabetic retinopathy (DR). The current study aimed to investigate the roles of SIRT1/miR-20a/Yse-associated protein (YAP)/hypoxia-inducible factor 1 α (HIF1α)/vascular endothelial growth factor A (VEGFA) in DR. The expression of SIRT1 was initially determined through quantitative RT-PCR and Western blot analysis following the successful establishment of a DR mouse model, followed by detection of SIRT1 catalytic activity. Retinal microvascular endothelial cells (RMECs) were cultured in media supplemented with normal glucose (NG) or high glucose (HG). Thereafter, SIRT1 was either silenced or overexpressed in RMECs, after which EdU staining and Matrigel-based tube formation assay were performed to assess cell proliferation and tube formation. The binding relationship between YAP, HIF1α, and VEGFA was further illustrated using dual-luciferase reporter assay. Preretinal neovascular cell number was tallied with the IB4-positive vascular endothelial cells, as determined by immunofluorescence. SIRT1 was poorly expressed in mice with DR and HG-treated RMECs with low catalytic activity. The proliferation and tube formation capabilities of RMECs were elevated under HG conditions, which could be reversed following overexpression of SIRT1. SIRT1 was identified as positively regulating the expression of miR-20a with YAP detected as the key target gene of miR-20a. Our data suggested that YAP could upregulate VEGFA via induction of HIF1α. Moreover, SIRT1 overexpression strongly repressed RMEC proliferation and angiogenesis, which could be reversed via restoration of YAP/HIF1α/VEGFA expression. Taken together, the key findings of our study suggest that upregulation of SIRT1 inhibits the development of DR via miR-20a-induced downregulation of YAP/HIF1α/VEGFA.

MicroRNA and vascular pathology of the eye

Since the discovery of microRNAs just a few decades ago, our knowledge of these molecules and their potential as diagnostic biomarkers and therapeutic targets has significantly expanded. There is an ongoing discussion in the scientific community about the possibility of using microRNA for the diagnosis of cardiovascular diseases. It has been shown recently that levels of some microRNAs vary in vascular eye disorders, such as age-related macular degeneration and diabetic retinopathy. However, despite serious advances in our understanding of microRNA’s role in eye pathology, we still do not know whether it is possible to use microRNA as a biomarker for central retinal vein occlusion. Perhaps, the discovery of such candidate microRNAs will help in making the timely diagnosis and improve the quality of medical care in patients with retinal vein occlusion.

Molecular biomarkers in diabetes mellitus (DM)

Background: Diabetes mellitus (DM) is a growing epidemic metabolic syndrome, which affects near 5.6% of the world's population. Almost 12% of health expenditure is dedicated to this disorder. Discovering and developing biomarkers as a practical guideline with high specificity and sensitivity for the diagnosis, prognosis, and clinical management of DM is one of the subjects of great interest among DM researchers due to the long-lasting asymptomatic clinical manifestation of DM. In this study, we described a recently identified molecular biomarker involved in DM. Methods: This review study was done at the Diabetes Research Center affiliated to Shahid Sadoughi University of Medical Sciences. PubMed, Scopus, Google Scholar, and Web of Science were searched using the following keywords: "diabetes mellitus", "biomarker", "microRNA", "diagnostic tool" and "clinical manifestation." Results: A total of 107 studies were finally included in this review. After evaluating numerous articles, including original, metaanalysis, and review studies, we focused on molecular biomarkers involved in DM diagnosis and management. Conclusion: Increasing interest in biomarkers associated with DM goes back to its role in decreasing diabetes-related morbidity and mortality. This review focused on major molecular biomarkers such as proteomic and microRNA (miRNAs) as novel and interesting DM biomarkers that can help achieve timely diagnosis of DM.

OIP5-AS1 Attenuates Microangiopathy in Diabetic Mouse by Regulating miR-200b/ACE2

OBJECTIVE

This study aimed to investigate OIP5-AS1 effects on microangiopathy in diabetic mouse.

METHODS

The expression levels of OIP5-AS1, miR-200b, and ACE2 expression were measured by RT-qPCR. Western blot was conducted to detect The ACE2 and Ang-(1-7) expression. Luciferase reporter assays were used to identify the interaction between miR-200b and OIP5-AS1 or ACE2. Morris water maze test was performed for detecting cognitive function.

RESULTS

Our results indicated that diabetic mice exhibited much lower OIP5-AS1 expression in the hippocampus than normal mice. Diabetic mice of OIP5-AS1 KO group showed remarkably lower OIP5-AS1 expression in the hippocampus, longer escape latency and lower percentage of CD31+ cells in the hippocampusthan those of WT group. OIP5-AS1 knockdown directly up-regulated miR-200b expression and ACE2 was directly inhibited by miR-200b. Relative to normal mice, diabetic mice had markedly higher miR-200b expression and lower ACE2 expression in the hippocampus. Diabetic mice of OIP5-AS1 KO group were with obviously higher miR-200b expression and lower ACE2 expression in the hippocampus than those of WT group. Compared with diabetic mice of OIP5-AS1 KO group, those of WT group, OIP5-AS1 KO + miR-200b inhibitor group and OIP5-AS1 KO + ACE2 group had obviously shorter escape latency and higher percentage of CD31⁺ cells and more caspase-3 protein expression in the hippocampus.

CONCLUSIONS

OIP5-AS1 attenuated microangiopathy in diabetic mouse by regulating miR-200b/ACE2.

MicroRNAs in Vascular Eye Diseases

Since the discovery of the first microRNA (miRNA) decades ago, studies of miRNA biology have expanded in many biomedical research fields, including eye research. The critical roles of miRNAs in normal development and diseases have made miRNAs useful biomarkers or molecular targets for potential therapeutics. In the eye, ocular neovascularization (NV) is a leading cause of blindness in multiple vascular eye diseases. Current anti-angiogenic therapies, such as anti-vascular endothelial growth factor (VEGF) treatment, have their limitations, indicating the need for investigating new targets. Recent studies established the roles of various miRNAs in the regulation of pathological ocular NV, suggesting miRNAs as both biomarkers and therapeutic targets in vascular eye diseases. This review summarizes the biogenesis of miRNAs, and their functions in the normal development and diseases of the eye, with a focus on clinical and experimental retinopathies in both human and animal models. Discovery of novel targets involving miRNAs in vascular eye diseases will provide insights for developing new treatments to counter ocular NV.

Oxidative stress-induced angiogenesis is mediated by miR-205-5p

miR‐205‐5p is known to be involved in VEGF‐related angiogenesis and seems to regulate associated cell signalling pathways, such as cell migration, proliferation and apoptosis. Therefore, several studies have focused on the potential role of miR‐205‐5p as an anti‐angiogenic factor. Vascular proliferation is observed in diabetic retinopathy and the ‘wet’ form of age‐related macular degeneration. Today, the most common treatments against these eye‐related diseases are anti‐VEGF therapies. In addition, both AMD and DR are typically associated with oxidative stress; hence, the use of antioxidant agents is accepted as a co‐adjuvant therapy for these patients. According to previous data, ARPE‐19 cells release pro‐angiogenic factors when exposed to oxidative insult, leading to angiogenesis. Matching these data, results reported here, indicate that miR‐205‐5p is modulated by oxidative stress and regulates VEGFA‐angiogenesis. Hence, miR‐205‐5p is proposed as a candidate against eye‐related proliferative diseases.

Long noncoding RNA MALAT1 participates in the pathological angiogenesis of diabetic retinopathy in an oxygen-induced retinopathy mouse model by sponging miR-203a-3p

Diabetic retinopathy (DR) is a devastating complication of diabetes. The aim of the present study is to investigate the exact role and mechanism of long noncoding RNA MALAT1 (MALAT1) in the progress of DR. An oxygen-induced retinopathy (OIR) mouse model and high glucose (HG) stimulated human retinal microvascular endothelial cells (HRMECs) were employed to mimic the pathological statues of DR. Quantitative real-time PCR (qRT-PCR) and Western blot results showed that MALAT1, VEGFA, and HIF-1α levels were increased in DR retinal tissues and HG-stimulated HRMECs, whereas the expression of miR-203a-3p was decreased. Knockdown of MALAT1 or upregulation of miR-203a-3p both suppressed HG-induced proliferation, migration, and tube formation of HRMECs. A dual-luciferase reporter assay showed that miR-203a-3p could bind to the predicted seed regions of MALAT1 as evidenced by the reduced luciferase activity. Furthermore, enforced downregulation of miR-203a-3p abolished the suppressive effect of MALAT1 silencing on HRMEC cell migration and tube formation. In conclusion, these data demonstrated that MALAT1 may affect angiogenesis by sponging miR-203a-3p in DR, suggesting that MALAT1 may act as a novel therapeutic target for the treatment of DR.

MicroRNAs as biomarkers of diabetic retinopathy and disease progression

Diabetes mellitus, together with its complications, has been increasing in prevalence worldwide. Its complications include cardiovascular disease (e.g., myocardial infarction, stroke), neuropathy, nephropathy, and eye complications (e.g., glaucoma, cataracts, retinopathy, and macular edema). In patients with either type 1 or type 2 diabetes mellitus, diabetic retinopathy is the leading cause of visual impairment or blindness. It is characterized by progressive changes in the retinal microvasculature. The progression from nonproliferative diabetic retinopathy to a more advanced stage of moderate to severe nonproliferative diabetic retinopathy and proliferative diabetic retinopathy occurs very quickly after diagnosis of mild nonproliferative diabetic retinopathy. The etiology of diabetic retinopathy is unclear, and present treatments have limited effectiveness. Currently diabetic retinopathy can only be diagnosed by a trained specialist, which reduces the population that can be examined. A screening biomarker of diabetic retinopathy with high sensitivity and specificity would aid considerably in identifying those individuals in need of clinical assessment and treatment. The majority of the studies reviewed identified specific microRNAs in blood serum/plasma able to distinguish diabetic patients with retinopathy from those without retinopathy and for the progresion of the disease from nonproliferative diabetic retinopathy to proliferative diabetic retinopathy. In addition, certain microRNAs in vitreous humor were dysregulated in proliferative diabetic retinopathy compared to controls. A very high percentage of patients with diabetic retinopathy develop Alzheimer's disease. Thus, identifying diabetic retinopathy by measurement of suitable biomarkers would also enable better screening and treatment of those individuals at risk of Alzheimer's disease.

Downregulation of circRNA DMNT3B contributes to diabetic retinal vascular dysfunction through targeting miR-20b-5p and BAMBI

Background

Diabetic retinopathy, a vascular complication of diabetes mellitus, is the leading cause of visual impairment and blindness. circRNAs act as competing endogenous RNA, sponging target miRNA and thus influencing mRNA expression in vascular diseases. We investigated whether and how circDNMT3B is involved in retinal vascular dysfunction under diabetic conditions.

Methods

qRT-PCR was performed to detect expression of circDNMT3B, miR-20b-5p, and BAMBI in retinal microvascular endothelial cells under diabetic conditions. Western blot, Cell Counting Kit-8, Transwell, Matrigel tube formation, and retinal trypsin digestion assays were conducted to explore the roles of circDNMT3B/miR-20b-5p/BAMBI in retinal vascular dysfunction. Bioinformatics analysis and luciferase reporter, siRNA, and overexpression assays were used to reveal the mechanisms of the circDNMT3B/miR-20b-5p/BAMBI interaction. Electroretinograms were used to evaluate visual function.

Findings

Upregulation of miR-20b-5p under diabetic conditions promoted proliferation, migration, and tube formation of human retinal microvascular endothelial cells (HRMECs), which was mediated by downregulated BAMBI. Under diabetic conditions, circDNMT3B, which acts as a sponge of miR-20b-5p, is downregulated. circDNMT3B overexpression reduced retinal acellular capillary number and alleviated visual damage in diabetic rats. Changes in expression of circDNMT3B and miR-20b-5p were confirmed in the proliferative fibrovascular membranes of patients with diabetic retinopathy.

Interpretation

Downregulation of circDNMT3B contributes to vascular dysfunction in diabetic retinas through regulating miR-20b-5p and BAMBI, providing a potential treatment strategy for diabetic retinopathy.

Funding

National Natural Science Foundation of China, National Key Basic Research Program of China, Shanghai Municipal Science and Technology Major Project, and ZJLab.

miRNA-200b improves hepatic fibrosis induced by CCL4 by regulating toll-like receptor 4 in mice

To study the effect of miRNA-200b on hepatic fibrosis induced by CCl4 in mice. The C59BL/6 mice were randomly divided into three groups (normal control [NC], CCLR model [Model], and CCl 4  + miRNA-200b [miRNA]). The hepatic fibrosis was induced by CCl 4 injected subcutaneously twice per week in Model and miRNA groups. After 6 weeks building model, the mice of miRNA group were injected the miRNA-200b from caudal vein twice per week. The mice of Model and miRNA groups were continuously fed for 3 weeks. The IL-1β, IL-6, and TNF-α concentrations of serum were measured by enzyme-linked immunosorbent assay. The hepatic tissues of difference groups were observed by hematoxylin and eosin (H&E) staining, sirius red staining, Masson staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling assay and measured toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) proteins expressions by western blot assay. The correlation between miRNA-200b and TLR4 were analyzed by dual luciferase target assay. Compared with NC group, the interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) concentrations of Model group were significantly upregulated (P < 0.05, respectively). With miRNA-200b overexpression, the IL-1β, IL-6, and TNF-α concentrations were significantly suppressed (P < 0.05, respectively). The pathologies were improved by H&E staining, sirius red staining, and Masson staining; meanwhile, the hepatic cell apoptosis rate was significantly suppressed (P < 0.05). The TLR4 and NF-κB protein expressions of miRNA group were significantly suppressed compared with the Model group (P < 0.05, respectively). By dual luciferase target assay, the TLR4 was a target gene of miRNA-200b. The miRNA-200b upregulation improved hepatic fibrosis induced by CCl 4 via regulation of TLR4 in vivo.

Long non-coding RNA HEIH contributes to diabetic retinopathy by regulating miR-939/VEGF axis

Diabetes is one of the most prevalent metabolic diseases in the world. This study explored the role of long non-coding RNA HEIH in regulating the development of diabetic retinopathy (DR). The expression of HEIH gene was detected in the serum of patients with DR. Subsequently, high concentrations of D-glucose (HG) were used to stimulate ARPE-19 cells to construct a cell model of DR. HEIH was overexpressed and suppressed to further investigate the effects of HEIH on HG-induced ARPE-19 cell injury. Moreover, the regulatory relationship between HEIH and miR-939 was investigated, and a target relationship between miR-939 and VEGF in ARPE-19 cells was explored. We elucidated an association between HEIH/miR-939/VEGF axis and the PI3K/AKT pathway. HEIH was highly expressed in the serum of patients with DR. Moreover, HG-induced ARPE-19 cell injury and expression of HEIH. The overexpression of HEIE aggravated HG-induced ARPE-19 cell injury by significantly inhibiting cell viability, inducing apoptosis, promoting cytochrome C release from mitochondria to cytoplasm, and enhancing the caspase-3 activity, whereas suppression of HEIE had the opposite effects. In addition, the effects of the suppression of HEIH on HG-induced ARPE-19 cell injury were markedly reversed by inhibiting miR-939. miR-939 regulated HG-induced ARPE-19 cell injury by targeting VEGF. The suppression of HEIH reversed HG-induced activation of the PI3K/AKT signaling pathway. Our findings revealed that HEIH may contribute to DR by sponging miR-939 to target VEGF expression and by regulating the activation of the PI3K/AKT pathway. Inhibition of epidermal growth factor receptor and PI3K/Akt signaling suppresses cell proliferation and survival through regulation of Stat3 activation in human cutaneous squamous cell carcinoma. HEIH/miR-939/VEGF axis may provide a novel perspective for DR therapy.

MMP targeting in the battle for vision: Recent developments and future prospects in the treatment of diabetic retinopathy

Matrix metalloproteinases (MMPs) are enzymes capable of degrading nearly all types of extracellular matrix. They perform a wide range of roles in physiological processes, which is the reason for their strict regulation by numerous mechanisms including natural tissue inhibitors of metalloproteinases (TIMP). Research only started to shed light on more troublesome aspects of MMPs function, like cancer progression, Alzheimer's disease, atherosclerosis, ageing. Moreover, their profound role in diabetes is being carefully investigated including one of its most debilitating complications - diabetic retinopathy (DR), the leading cause of acquired blindness worldwide. Traditional treatment of this condition seems to be only mildly satisfactory, which elicited substantial interest in the field of new therapeutic methods including MMP targeting. So far, significant roles of MMP-2 and MMP-9 in the development of retinopathy have been established, with special attention given to the process of blood-retinal barrier impairment. Further exploration revealed MMP-10 and MMP-14 involvement as well as changes in MMP/TIMP ratio. In this review, we provide insight into MMPs role in diabetic retinopathy with a clarification of various mechanisms regulating MMP activity in the light of the recent studies. We conclude with an overview of novel DR therapies targeting MMPs and point to the need of further examination of their usefulness in clinical setting, with an eye towards future research.

Increased Extracellular Matrix Protein Production in Chronic Diabetic Complications: Implications of Non-Coding RNAs

Management of chronic diabetic complications remains a major medical challenge worldwide. One of the characteristic features of all chronic diabetic complications is augmented production of extracellular matrix (ECM) proteins. Such ECM proteins are deposited in all tissues affected by chronic complications, ultimately causing organ damage and dysfunction. A contributing factor to this pathogenetic process is glucose-induced endothelial damage, which involves phenotypic transformation of endothelial cells (ECs). This phenotypic transition of ECs, from a quiescent state to an activated dysfunctional state, can be mediated through alterations in the synthesis of cellular proteins. In this review, we discussed the roles of non-coding RNAs, specifically microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), in such processes. We further outlined other epigenetic mechanisms regulating the biogenesis and/or function of non-coding RNAs. Overall, we believe that better understanding of such molecular processes may lead to the development of novel biomarkers and therapeutic strategies in the future.

Plasma levels of miR-29b and miR-200b in type 2 diabetic retinopathy

MicroRNAs (miRNAs/miRs) are involved in the pathogenesis of diabetes mellitus and its chronic complications, and their circulating levels have emerged as potential biomarkers for the development and progression of diabetes. However, few studies have examined the expression of miRNAs in diabetic retinopathy (DR) in humans. This case-control study aimed to investigate whether the plasma levels of miR-29b and miR-200b are associated with DR in 186 South Brazilians with type 2 diabetes (91 without DR, 46 with non-proliferative DR and 49 with proliferative DR). We also included 20 healthy blood donors to determine the miRNA expression in the general population. Plasma levels of miR-29b and miR-200b were quantified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Proliferative DR was inversely associated with plasma levels of miR-29b (unadjusted OR = 0.694, 95% CI: 0.535-0.900, P = 0.006) and miR-200b (unadjusted OR = 0.797, 95% CI: 0.637-0.997, P = 0.047). However, these associations were lost after controlling for demographic and clinical covariates. In addition, patients with type 2 diabetes had lower miR-200b levels than blood donors. Our findings reinforce the importance of addressing the role of circulating miRNAs, including miR-29 and miR-200b, in DR.

Remodeling of Retinal Architecture in Diabetic Retinopathy: Disruption of Ocular Physiology and Visual Functions by Inflammatory Gene Products and Pyroptosis

Diabetic patients suffer from a host of physiological abnormalities beyond just those of glucose metabolism. These abnormalities often lead to systemic inflammation via modulation of several inflammation-related genes, their respective gene products, homocysteine metabolism, and pyroptosis. The very nature of this homeostatic disruption re-sets the overall physiology of diabetics via upregulation of immune responses, enhanced retinal neovascularization, upregulation of epigenetic events, and disturbances in cells' redox regulatory system. This altered pathophysiological milieu can lead to the development of diabetic retinopathy (DR), a debilitating vision-threatening eye condition with microvascular complications. DR is the most prevalent cause of irreversible blindness in the working-age adults throughout the world as it can lead to severe structural and functional remodeling of the retina, decreasing vision and thus diminishing the quality of life. In this manuscript, we attempt to summarize recent developments and new insights to explore the very nature of this intertwined crosstalk between components of the immune system and their metabolic orchestrations to elucidate the pathophysiology of DR. Understanding the multifaceted nature of the cellular and molecular factors that are involved in DR could reveal new targets for effective diagnostics, therapeutics, prognostics, preventive tools, and finally strategies to combat the development and progression of DR in susceptible subjects.

PIWI-like protein, HIWI2: A novel player in proliferative diabetic retinopathy

Diabetic retinopathy (DR) is one of the major causes of blindness resulting from prolonged hyperglycemia which leads to breakdown of blood retinal barrier and excessive neovascularization. In our previous study, we demonstrated the presence of germline-specific PIWI-like proteins in human retina and retinal pigment epithelium (RPE) and a discrete function of HIWI2 (PIWIL4) in the assembly of tight junction through Akt/GSK3α/β. Recently, PIWI/piRNA has been suggested to be involved in the development of diabetes. Here, we have investigated the role of HIWI2 in proliferative diabetic retinopathy (PDR). Interestingly, Western blot analysis indicated the elevated expression of HIWI2 in vitreous aspirates of patients with PDR in comparison to macular hole (MH) and rhegmatogenous retinal detachment (RRD). In addition, treatment of ARPE19 with 25% of PDR vitreous aspirate significantly increased the expression of HIWI2. Moreover, exposure of ARPE19 to oxidative stress and VEGF, induced the expression of HIWI2. Further, we knocked down HIWI2 in ARPE19 cells to understand its role in the disease progression. Silencing HIWI2 reduced the expression of growth factors, VEGF and TGFβ1, and altered the expression of epithelial to mesenchymal transition (EMT) markers E-cadherin and αSMA. In addition, expression of MMP9 and cell migration was reduced in Si-HIWI2. Collectively, our report highlights a novel function and association of a piRNA binding protein, HIWI2 to PDR. The elevated expression of HIWI2 in PDR could influence various aspects of the disease pathogenesis, like EMT changes and cell migration. Hence, understanding the exact function of HIWI2 in retina could reveal its potential as a therapeutic target for retinopathy.

miR-200b downregulates Kruppel Like Factor 2 (KLF2) during acute hypoxia in human endothelial cells

The role of microRNAs in controlling angiogenesis is recognized as a promising therapeutic target in both cancer and cardiovascular disorders. However, understanding a miRNA's pleiotropic effects on angiogenesis is a limiting factor for these types of therapeutic approaches. Using genome-wide next-generation sequencing, we examined the role of an antiangiogenic miRNA, miR-200b, in primary human endothelial cells. The results indicate that miR-200b has complex effects on hypoxia-induced angiogenesis in human endothelia and importantly, that many of the reported miR-200b effects using miRNA overexpression may not be representative of the physiological role of this miRNA. We also identified the antiangiogenic KLF2 gene as a novel target of miR-200b. Our studies indicate that the physiological changes in miR-200b levels during acute hypoxia may actually have a proangiogenic effect through Klf2 downregulation and subsequent stabilization of HIF-1 signaling. Moreover, we provide a viable approach for differentiating direct from indirect miRNA effects in order to untangle the complexity of individual miRNA networks.

Roles of miRNAs and long noncoding RNAs in the progression of diabetic retinopathy

Diabetic retinopathy (DR) is the leading cause of blindness in working-age adults across the world. The pathogenesis of DR is multifactorial and the molecular mechanisms are still not fully understood. Accumulating evidence has demonstrated that noncoding RNAs (ncRNAs) may be aberrantly expressed and may play vital roles in the development of DR. Amongst ncRNAs, miRNAs and long ncRNAs (lncRNAs) are known for their regulatory functions. Here, we summarize the functions and mechanisms of known aberrantly expressed miRNAs and lncRNAs in DR. Additionally, a novel lncRNA–mRNA–miRNA network is included in this review. We highlight original studies that provide detailed data about the mechanisms of miRNAs and lncRNAs, their applications as diagnostic or prognostic biomarkers, and their potential therapeutic targets. In conclusion, this review will help us gain a better understanding of the molecular mechanisms by which miRNAs and lncRNAs perform their functions in DR, and provide general strategies and directions for future research.

MicroRNA-299-3p suppresses proliferation and invasion by targeting VEGFA in human colon carcinoma

Accumulating evidences have shown that microRNAs (miRNAs) are vital regulators and possess huge capabilities in post-transcriptional control. Although a large number of miRNAs have been identified to be dysregulated in human cancers especially in colon cancer, our understandings of the function of most miRNAs are still largely limited. In this study, we have demonstrated that miR-299-3p plays a critical role in suppressing colon carcinoma progression by targeting Vascular Endothelial Growth Factor A (VEGFA). We observed that miR-299-3p was down-regulated in colon carcinoma tissues and colon cancer cell lines. The level of miR-299-3p was significantly negatively correlated with that of VEGFA mRNA level in colon carcinoma. More importantly, the low level of miR-299-3p predicted poor prognosis of colon cancer patients. Functionally, overexpression of miR-299-3p inhibited the proliferation and invasion of colon carcinoma cells and suppressed the growth of colon cancer xenografts in nude mice. Luciferase reporter assays showed that miR-299-3p could target VEGFA 3' UTR. In addition, up-regulation of miR-299-3p decreased VEGFA expression both in vitro and in vivo, showing that miR-299-3p plays a suppressive effect on VEGFA via post-transcriptional control. However, ectopical expression of VEGFA could abrogate this effect and also abolish miR-299-3p-induced inhibition of cell proliferation and invasion. Taken together, our study provides evidences showing that miR-299-3p functions as a suppressor in colon cancer by targeting VEGFA, suggesting that miR-299-3p might serve as a novel target for colon cancer therapy.