Gene Expression In Retinal Cells Research Articles

Crosstalk between MIR-96 and IRS/PI3K/AKT/VEGF cascade in hRPE cells; A potential target for preventing diabetic retinopathy.

Regulation of visual system function demands precise gene regulation. Dysregulation of miRNAs, as key regulators of gene expression in retinal cells, contributes to different eye disorders such as diabetic retinopathy (DR), macular edema, and glaucoma. MIR-96, a member of the MIR-183 cluster family, is widely expressed in the retina, and its alteration is associated with neovascular eye diseases. MIR-96 regulates protein cascades in inflammatory and insulin signaling pathways, but further investigation is required to understand its potential effects on related genes. For this purpose, we identified a series of key target genes for MIR-96 based on gene and protein interaction networks and utilized text-mining resources. To examine the MIR-96 impact on candidate gene expression, we overexpressed MIR-96 via adeno-associated virus (AAV)-based plasmids in human retinal pigment epithelial (RPE) cells. Based on Real-Time PCR results, the relative expression of the selected genes responded differently to overexpressed MIR-96. While the expression levels of IRS2, FOXO1, and ERK2 (MAPK1) were significantly decreased, the SERPINF1 gene exhibited high expression simultaneously. pAAV-delivered MIR-96 had no adverse effect on the viability of human RPE cells. The data showed that changes in insulin receptor substrate-2 (IRS2) expression play a role in disrupted retinal insulin signaling and contribute to the development of diabetic complications. Considered collectively, our findings suggest that altered MIR-96 and its impact on IRS/PI3K/AKT/VEGF axis regulation contribute to DR progression. Therefore, further investigation of the IRS/PI3K/AKT/VEGF axis is recommended as a potential target for DR treatment.

Statement of Retraction: A new Cu (II)-coordination polymer: inhibiting bcl-2 gene expression in retinal cells and exerting treatment activity on diabetic retinopathy

Statement of Retraction: A new Cu (II)-coordination polymer: inhibiting bcl-2 gene expression in retinal cells and exerting treatment activity on diabetic retinopathy

A single-cell guide to retinal development: Cell fate decisions of multipotent retinal progenitors in scRNA-seq

Recent advances in high throughput single-cell RNA sequencing (scRNA-seq) technology have enabled the simultaneous transcriptomic profiling of thousands of individual cells in a single experiment. To investigate the intrinsic process of retinal development, researchers have leveraged this technology to quantify gene expression in retinal cells across development, in multiple species, and from numerous important models of human disease. In this review, we summarize recent applications of scRNA-seq and discuss how these datasets have complemented and advanced our understanding of retinal progenitor cell competence, cell fate specification, and differentiation. Finally, we also highlight the outstanding questions in the field that advances in single-cell data generation and analysis will soon be able to answer.

RETRACTED ARTICLE: A new Cu (II)-coordination polymer: inhibiting bcl-2 gene expression in retinal cells and exerting treatment activity on diabetic retinopathy

We, the Editors and Publisher of the journal Inorganic and Nano-Metal Chemistry, have retracted the following article: An-Dai Wu & Hai-Long Lu. A new Cu (II)-coordination polymer: inhibiting bcl-2 gene expression in retinal cells and exerting treatment activity on diabetic retinopathy, Inorganic and Nano-Metal Chemistry. 2021, VOL. 51, NO. 11, 1453–1458, DOI: 10.1080/24701556.2020.1841228 Since publication, concerns have been raised about the integrity of the data in the article. When approached for an explanation, the authors have been unable to address the concerns raised and have not been able to provide sufficient supporting information. As verifying the validity of published work is core to the integrity of the scholarly record, we are therefore retracting the article. The corresponding author listed in this publication has been informed. The authors have agreed to the retraction. We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’.

The Relationships between SORD -888G>C Gene Polymorphism and Diabetic Retinopathy in a South Sumatran Malay Population

The sorbitol dehydrogenase (SORD) enzyme has 2 promoter regions with polymorphisms at -1214 C>G (rs2055858) and -888 G>C (rs3759890), which have a complete imbalance, related to gene expression in retinal cells of diabetic patients, and more likely to have a role in diabetic retinopathy (DR) pathogenesis. The SORD -888G>C genotype occurs more often in Japanese DR patients than in patients without complications. A relationship between DR and the G allele in -888G>C polymorphism is observed in Diabetes Mellitus (DM) type-2 patients. This study aims to elucidate the relationship between the SORD -888 G>C gene polymorphism to the occurrence of DR cases in Malay population in South Sumatra. This is a case-control study. Malay DM type-2 patients who undergo direct ophthalmoscopy and fundus imaging in the Dr. Mohammad Husein Central General Hospital eye clinic in Palembang, South Sumatra, Indonesia were the subjects of this study. Patient DNA was isolated from blood samples, PCR analyzed and sequenced in order to determine the polymorphism frequencies of the SORD -888 G>C gene. The results showed that every subject had GG genotype in SORD -888 G>C gene promoter. There was no observable polymorphism in SORD -888G>C gene in the authentic Malay population in South Sumatra.

Fetal Alcohol Syndrome Effects in Retinal Cell Gene Expression and Development

Alcohol exposure during embryonic development has many adverse effects on development, and this is termed fetal alcohol spectrum disorder (FASD). Retinal development is consistently affected by ethanol exposure in animal models, and vision is frequently impaired in human patients. The zebrafish is an excellent model to study FASD due to their experimental accessibility and similar developmental pathways to humans. Previous studies show that ethanol exposure caused retinal cell differentiation defects leading to retinal defects, including photoreceptor defects. These defects persist in to juvenile stages, suggesting that the retinal stem cells are permanently altered. This research aims to understand gene expression changes that occur in retinal cells in the retina, and particularly the ciliary marginal zone (CMZ) stem cell compartment due to ethanolexposure. Zebrafish embryos exposed to ethanol [100, 150 mM EtOH], from 2–24 hours postfertilization (hpf), were grown in regular medium until 72 hpf. Eyes from ethanol treated and control zebrafish embryos were dissected and total RNA was isolated.. The RNA is then purified and then reverse transcribed into cDNA. Quantitative PCR was then used to analyze the cDNA using gene specific primers to determine relative expression levels of various genes present in the retinal developmental pathway. Experiments examined specific signaling pathways including, wnt, notch and proneural gene targets, and other specific markers expressed by retinal precursor cell and differentiating cell populations. This research will provide insight into gene expression changes affecting retinal development in specific cell types after alcohol exposure. Our goal is to understand the genesis of FASD birth defects caused by ethanol exposure, and this research will possibly identify ethanol toxicity targets and therapeutic strategies to prevent or reverse the damage.Support or Funding InformationResearch was supported by NIAAA.

Development of gene therapy for treatment of age-related macular degeneration.

Intraocular neovascular diseases are the leading cause of blindness in the Western world in individuals over the age of 50. Age-related macular degeneration (AMD) is one of these diseases. Exudative AMD, the late-stage form, is characterized by abnormal neovessel development, sprouting from the choroid into the avascular subretinal space, where it can suddenly cause irreversible damage to the vulnerable photoreceptor (PR) cells essential for our high-resolution, central vision. The molecular basis of AMD is not well understood, but several growth factors have been implicated including vascular endothelial growth factor (VEGF), and the advent of anti-VEGF therapy has markedly changed the outcome of treatment. However, common to all current therapies for exudative AMD are the complications of repeated monthly intravitreal injections, which must be continued throughout one's lifetime to maintain visual benefits. Additionally, some patients do not benefit from established treatments. Strategies providing long-term suppression of inappropriate ocular angiogenesis are therefore needed, and gene therapy offers a potential powerful technique. This study aimed to develop a strategy based on RNA interference (RNAi) for the sustained attenuation of VEGF. We designed a panel of anti-VEGF short hairpin RNAs (shRNA), and based on the most potent shRNAs, microRNA (miRNA)-mimicked hairpins were developed. We demonstrated an additive VEGF silencing effect when we combined the miRNAs in a tricistronic miRNA cluster. To meet the requirements for development of medical treatments for AMD with long-term effects, the shRNA/miRNA is expressed from vectors based on adeno-associated virus (AAV) or lentivirus (LV). Both vector systems have been found superior in terms of transduction efficiency and persistence in gene expression in retinal cells. The capacity of AAV-encoded RNAi effector molecules to silence endogenous VEGF gene expression was evaluated in mouse models, including the model of laser-induced choroidal neovascularization (CNV), and we found that subretinal administration of self-complementary (sc)-AAV2/8 encoding anti-VEGF shRNAs can impair vessel formation. In parallel, a significant reduction of endogenous VEGF was demonstrated following injection of scAAV2/8 vectors expressing multiple anti-VEGF miRNAs into murine hind limb muscles. Furthermore, in an ongoing project we have designed versatile, multigenic LV vectors with combined expression of multiple miRNAs and proteins, including pigment epithelium-derived factor (PEDF), a multifunctional, secreted protein that has anti-angiogenic and neurotrophic functions. Co-expression of miRNAs and proteins from a single viral vector increases safety by minimizing the viral load necessary to obtain a therapeutic effect and thereby reduces the risk of insertional mutagenesis as well as the immune response against viral proteins. Our results show co-expression of functional anti-VEGF-miRNAs and PEDF in cell studies, and in vivo studies reveal an efficient retinal pigment epithelium (RPE)-specific gene expression following the incorporation of the vitelliform macular dystrophy 2 (VMD2) promoter, demonstrating the potential applicability of our multigenic LV vectors in ocular anti-VEGF gene therapy, including combination therapy for treatment of exudative AMD. In conclusion, these highly promising data clearly demonstrate that viral-encoded RNAi effector molecules can be used for the inhibition of neovascularization and will, in combination with the growing interest of applying DNA- or RNA-based technologies in the clinic, undoubtedly contribute to the development of efficacious long-term gene therapy treatment of intraocular neovascular diseases.

Ocular Delivery of Compacted DNA-Nanoparticles Does Not Elicit Toxicity in the Mouse Retina

Subretinal delivery of polyethylene glycol-substituted lysine peptide (CK30PEG)-compacted DNA nanoparticles results in efficient gene expression in retinal cells. This work evaluates the ocular safety of compacted DNA nanoparticles. CK30PEG-compacted nanoparticles containing an EGFP expression plasmid were subretinally injected in adult mice (1 µl at 0.3, 1.0 and 3.0 µg/µl). Retinas were examined for signs of inflammation at 1, 2, 4 and 7 days post-injection. Neither infiltration of polymorphonuclear neutrophils or lymphocytes was detected in retinas. In addition, elevation of macrophage marker F4/80 or myeloid marker myeloperoxidase was not detected in the injected eyes. The chemokine KC mRNA increased 3–4 fold in eyes injected with either nanoparticles or saline at 1 day post-injection, but returned to control levels at 2 days post-injection. No elevation of KC protein was observed in these mice. The monocyte chemotactic protein-1, increased 3–4 fold at 1 day post-injection for both nanoparticle and saline injected eyes, but also returned to control levels at 2 days. No elevations of tumor necrosis factor alpha mRNA or protein were detected. These investigations show no signs of local inflammatory responses associated with subretinal injection of compacted DNA nanoparticles, indicating that the retina may be a suitable target for clinical nanoparticle-based interventions.