miR-204-5p promotes diabetic retinopathy development via downregulation of microtubule-associated protein 1 light chain 3

TFEB attenuates hyperglycemia-induced retinal capillary endothelial cells injury via autophagy regulation

Diabetic retinopathy is a common microvascular complication of diabetes mellitus. The maintenance of retinal capillary endothelial cell homeostasis requires a complete and unobtrusive flow of autophagy because it may help combat the inflammatory response, apoptosis, and oxidative stress damage of cells in diabetes mellitus. The transcription factor EB is a master regulator of autophagy and lysosomal biogenesis, but its role in diabetic retinopathy remains unknown. This study aimed to confirm the involvement of transcription factor EB in diabetic retinopathy and explore the role of transcription factor EB in hyperglycemia-linked endothelial injury in vitro. First, the expression levels, including the nuclear location of transcription factor EB and autophagy, were reduced in diabetic retinal tissues and high glucose-treated human retinal capillary endothelial cells. Subsequently, autophagy was mediated by transcription factor EB in vitro. Moreover, transcription factor EB overexpression reversed high glucose-induced autophagy inhibition and lysosomal dysfunction and protected human retinal capillary endothelial cells from inflammation, apoptosis, and oxidative stress damage caused by high glucose treatment. Additionally, under high-glucose stimulation, the autophagy inhibitor chloroquine attenuated transcription factor EB overexpression-mediated protection, and the autophagy agonist Torin1 rescued transcription factor EB knockdown-induced damage effects. Taken together, these results suggest that transcription factor EB is involved in the development of diabetic retinopathy. In addition, transcription factor EB protects human retinal capillary endothelial cells from high glucose-induced endothelial damage via autophagy.

Down-regulation of miR-204-5p ameliorates sevoflurane-induced brain injury in neonatal rats through targeting VCAM1

To confirm the regulation of miR-204-5p on VCAM1 and its effect on sevoflurane-induced brain injury in neonatal rats. We adopted the sevoflurane-induced brain injury model, and the double luciferase reporter gene assay was applied to explore the targeting relationship between vascular adhesion factor 1 (VCAM1) and miR-204-5p. RT-qPCR was applied to assess the levels of miR-204-5. VCAM1, LC3, P62 and cleaved-caspase 3 levels in the hippocampus were estimated by western blot. The number of autophagosomes in the cerebral cortex was assessed via Transmission electron microscopy (TEM), and histopathological changes within the hippocampus by HE staining. miR-204-5p levels were remarkably increased, but VCAM1 expression was decreased after neonatal rat brain injury. Furthermore, miR-204-5p directly targeted VCAM1. The escape latency, swimming distance, autophagosome number, neuronal apoptosis ratio, LC3 II and Cleaved-caspase 3 expression were reduced after miR-204-5p inhibition interference, whereas crossing times, and P62 expression increased in the sevoflurane-induced brain injury model. Furthermore down-regulation of VCAM1 reversed the trend of these indices. These results suggest that down-regulation of miR-204-5p ameliorates sevoflurane-induced cognitive impairment and hippocampal pathology and inhibits neuronal autophagy and apoptosis by targeting VCAM1.

Experiment-Based Interventions to Diabetic Retinopathy: Present and Advances

Diabetic retinopathy is the major blinding disease among working-age populations, which is becoming more significant due to the growth of diabetes. The metabolic-induced oxidative and inflammatory stress leads to the insult of neovascular unit, resulting in the core pathophysiology of diabetic retinopathy. Existing therapies focus on the inflammation, oxidation, and angiogenesis phenomena of diabetic retinopathy, without effect to radically cure the disease. This review also summarizes novel therapeutic attempts for diabetic retinopathy along with their advantages and disadvantages, mainly focusing on those using cellular and genetic techniques to achieve remission on a fundamental level of disease.

Mechanism of miR-204-5p in exosomes derived from bronchoalveolar lavage fluid on the progression of pulmonary fibrosis via AP1S2

Background

Exosomes are nanoscale vesicles secreted by various types of cells that are responsible for intracellular communication. Despite that bronchoalveolar lavage fluid (BALF) has been proven to involve in tumor development, more efforts are required to investigate the impact of BALF on pulmonary fibrosis (PF). This study aimed to investigate the mechanism of how exosomal miR-204-5p from BALF facilitates PF progression in rats.

Methods

PF rat model was established by intratracheal injection of bleomycin. BALF-derived exosomes (Exo) were extracted from normal and PF rats. PF-Exo (BALF-derived Exo from PF rats) and miR-204-5p antagomir were injected into rats to investigate the effect of exosomal miR-204-5p on PF. Collagen content in lung tissues of rats was assessed by Masson staining, hydroxyproline (HYP) content assay and immunohistochemistry (IHC). Primary lung fibroblasts were isolated, and treated by TGF-β1. After co-transfection of PF-Exo, miR-204-5p inhibitor and sh-AP1S2, cell proliferation, levels of miR-204-5p, fibrotic markers α-SMA and collagen 1 (Col 1), and proteins of autophagy markers LC3II, LC3I and P62 were measured. The interaction between miR-204-5p and AP1S2 was determined by bioinformatics online software TargetScan and dual-luciferase reporter assay.

Results

miR-204-5p was abundantly expressed in the PF-Exo group. PF-Exo injection potentiated PF progression and proliferation ability of lung fibroblasts in vivo and in vitro. Injection with PF-Exo and miR-204-5p antagomir significantly increased the LC3II/I ratio and decreased the HYP content, proteins of α-SMA, Col 1 and P62, collagen content in rat lung tissues of PF rats. TGF-β1 induction elevated the LC3II/LC3I ratio, suppressed the cell proliferation rate, and decreased the levels of α-SMA, Col 1 and P62. Additionally, AP1S2 was a direct target of miR-204-5p. miR-204-5p inhibitor can counteract the effect of PF-Exo in proliferation of lung fibroblasts, while sh-AP1S2 eliminated the effect of miR-204-5p inhibitor.

Conclusions

Exosomal miR-204-5p from BALF inhibits autophagy to promote the progression of PF rats by targeting AP1S2.

Autophagy: A Novel Pharmacological Target in Diabetic Retinopathy

Autophagy is the major catabolic pathway involved in removing and recycling damaged macromolecules and organelles and several evidences suggest that dysfunctions of this pathway contribute to the onset and progression of central and peripheral neurodegenerative diseases. Diabetic retinopathy (DR) is a serious complication of diabetes mellitus representing the main preventable cause of acquired blindness worldwide. DR has traditionally been considered as a microvascular disease, however this concept has evolved and neurodegeneration and neuroinflammation have emerged as important determinants in the pathogenesis and evolution of the retinal pathology. Here we review the role of autophagy in experimental models of DR and explore the potential of this pathway as a target for alternative therapeutic approaches.

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.

Protective or Harmful: The Dual Roles of Autophagy in Diabetic Retinopathy

Autophagy is a self-degradative pathway involving intracellular substance degradation and recycling. Recently, this process has attracted a great deal of attention for its fundamental effect on physiological processes in cells, tissues, and the maintenance of organismal homeostasis. Dysregulation of autophagy occurs in some diseases, including immune disease, cancer, and neurodegenerative conditions. Diabetic retinopathy (DR), as a serious microvascular complication of diabetes, is the main cause of visual loss in working-age adults worldwide. The pathogenic mechanisms of DR are thought to be associated with accumulation of oxidative stress, retinal cell apoptosis, inflammatory response, endoplasmic reticulum (ER) stress, and nutrient starvation. These factors are closely related to the regulation of autophagy under pathological conditions. Increasing evidence has demonstrated the potential role of autophagy in the progression of DR through different pathways. However, to date this role is not understood, and whether the altered level of autophagy flux protects DR, or instead aggravates the progression, needs to be explored. In this review, we explore the alterations and functions of autophagy in different retinal cells and tissues under DR conditions, and explain the mechanisms involved in DR progression. We aim to provide a basis on which DR associated stress-modulated autophagy may be understood, and to suggest novel targets for future therapeutic intervention in DR.

Updates on Gene Therapy for Diabetic Retinopathy

PURPOSE OF REVIEW

Diabetic retinopathy (DR), a leading cause of visual impairment in the developed country, is characterized by vascular lesions and neuronal damage of the retina. Treatment options for this condition are currently limited. The advent of therapy targeting vascular endothelial growth factor (VEGF) demonstrated significant benefits to patients with DR. However, this treatment is limited by its short half-life and requirement for frequent invasive intravitreal injections. In addition, many patients failed to achieve clinically significant improvement in visual function. Gene therapy has the potential to provide an alternative treatment for DR with distinct advantages, such as longer therapeutic effect, less injection frequency, ability to intervene at disease onset, and potentially fewer side effects.

RECENT FINDINGS

Strategies for gene therapy in DR, stemming from the current understanding of the disease pathogenesis, focus on the inhibition of neovascularization and protection of neurovascular degeneration in the retina. Studies with promising results have mainly focussed on animal models due to efficacy and safety concerns, despite a number of successful preclinical studies using adeno-associated virus-mediated transduction to treat both vascular dysfunction and neuronal degeneration. With the optimization of delivery vectors, transgene regulation, and outcome measure, gene therapy will potentially become available for patients with DR. This review provides an update on the current strategies utilized in DR gene therapy research. Several barriers to the clinical application of gene therapy for DR are highlighted, and future directions for this research are proposed.

The long non-coding RNA LOC285758 promotes invasion of acute myeloid leukemia cells by down-regulating miR-204-5p

Acute myeloid leukemia (AML) is the second most common type of leukemia worldwide. It was previously reported that expression of the long noncoding RNA LOC285758 is positively associated with AML cell proliferation, but the underlying mechanisms have not previously been reported. Here, we report that LOC285758 expression is higher in clinical AML blood samples and cultured AML cells. miR‐204‐5p was confirmed to be a target gene of LOC285758 by bioinformatics analysis and luciferase assay. LOC285758 overexpression promoted AML cell viability and invasion abilities, which were effectively inhibited by miR‐204‐5p overexpression; moreover, miR‐204‐5p overexpression also regulated the expression of E‐cadherin, N‐cadherin and Twist1. The data also showed that increased LOC285758 expression could effectively suppress the earlier effects of miR‐204‐5p on AML cells. Our findings suggest that targeting of miR‐204‐5p by LOC285758 promotes the cell viability and invasion of AML cells, and thus LOC285758 may have potential as a therapeutic target for AML treatment.