Circ-CARD6 inhibits oxidative stress-induced apoptosis and autophagy in ARPE-19 cells via the miR-29b-3p/PRDX6/PI3K/Akt axis.

BACKGROUND: Oxidative stress-induced damage and dysfunction of retinal pigment epithelium (RPE) cells are important pathogenetic factors of age-related macular degeneration (AMD) and hereditary retinopathy diseases (HRDs). This study aimed to elucidate the roles and mechanisms of circ-CARD6 and miR-29b-3p in oxidative stress-induced RPE and provide new ideas for the diagnosis and treatment of retinopathy disease (RD). METHODS: A model of oxidative stress-induced RPE (ARPE-19) was established, and the level of malondialdehyde (MDA) and concentration of reactive oxygen species (ROS) were detected by a DCFH-DA fluorescent probe and MDA kit. The cell viability was measured by a CCK-8 assay. The expression of PRDX6/PI3K/Akt axis genes and proteins related to apoptosis and autophagy were determined by RT‒qPCR and Western blot analyses. The dual-luciferase reporter system confirmed the targeting relationship between miR-29b-3p and circ-CARD6 and between miR-29b-3p and PRDX6. RESULTS: In H2O2-treated ARPE-19 cells, the expression of circ-CARD6 and PRDX6 was decreased, while the expression of miR-29b-3p was increased. The overexpression of circ-CARD6 inhibits oxidative stress-induced increases in ROS, apoptosis and autophagy in ARPE-19 cells. circ-CARD6 targets miR-29b-3p, miR-29b-3p targets PRDX6, and circ-CARD6 regulates PRDX6 via miR-29b-3p. Further studies showed that circ-CARD6 acts as a competitive endogenous RNA of miR-29b-3p to affect the expression of PRDX6, thereby inhibiting autophagy and apoptosis in ARPE-19 cells. CONCLUSION: circ-CARD6 can inhibit oxidative stress and apoptosis by regulating the miR-29b-3p/PRDX6/PI3K/Akt axis.

A novel missense mutation in the CRYBA2 caused autosomal dominant presenile cataract in a Chinese family.

Presenile cataract is a relatively rare type of cataract, but its genetic mechanisms are currently not well understood. The precise identification of these causative genes is crucial for effective genetic counseling for patients and their families. The aim of our study was to identify the causative gene associated with presenile cataract in a Chinese family. In February 2020, a four-generation pedigree of presenile cataract patients was recruited at the 2nd Affiliated Hospital of Kunming Medical University. One patient and her healthy husband from the family underwent whole exome sequencing. The variant was validated through sanger sequencing, and co-segregation analysis was conducted in all family members to assess its pathogenicity. Molecular dynamics simulation (MDS) was used to analyze the conformation of both the wild type and pathogenic mutant loci p.Y153H of CRYBA2. We identified presenile cataract in the pedigree, which follows an autosomal-dominant pattern of inheritance. The family includes five clinically affected patients who all developed presenile cataract between the ages from 24 to 30. We confirmed the pathogenicity of a heterozygous missense variant (NM_057093:c.457T >C) in CRYBA2 within this family. The affected amino acid demonstrates high conservation across species. Subsequent sanger sequencing confirmed co-segregation of the disease in all family members. MDS analysis revealed that the p.Y153H mutant disrupted hydrogen bond formation between Y153 and R193 within the two ß-strands of the fourth Greek key domain, leading to destabilization of the ßA2-crystallin. In conclusion, a novel causative mutation (NM_057093:c.457T>C) in CRYBA2 might contribute to autosomal dominant presenile cataract.

Novel Advances in the Study of IgG4-Related Disease in the Eye and Ocular Adnexa.

Immunoglobin G4 (IgG4)-related disease in the eye and ocular adnexa (IgG4-ROD) is a newly discovered autoimmune disease that histologically exhibits extensive lymphocyte and plasma cell infiltration, occlusive phlebitis, and mat or whorled fibrosis. The disease can affect multiple ocular tissues and organs, such as the lacrimal gland, extraocular muscles, orbital fat, and trigeminal nerve. The main clinical manifestations are chronic, painless swelling of the orbit or unilateral orbit and proptosis, which may be accompanied by peripheral lymphadenopathy. Usually, visual impairment is not apparent, but in severe cases, it can cause a loss of function of the tissues and organs involved and affect the daily lives of patients. The pathogenesis of IgG4-ROD is not clear. Based on existing literature, it is speculated that it may be related to factors such as autoantibody production, microbial infection, and genetic inheritance. For the treatment of IgG4-ROD, glucocorticoids, immunosuppressive agents, biological agents, and surgery are mainly used in clinical practice. Although these treatment methods can achieve a particular effect, they have limitations, such as high recurrence rates, serious side effects, and postoperative complications. With the increase in IgG4-ROD-related reports, some progress has been made in the current understanding and research of the disease.

PRDX6 regulates the H2O2 and blue light-induced APRE-19 cell apoptosis via down-regulating and interacting with RARA.

Hereditary retinal disease (HRD) is the primary retinal degeneration that leads to severe visual impairments and refractory blindness, and the therapy of HRD was most important in ophthalmology. The apoptosis of retinal cells plays important roles in HRD progression. Therefore, in this study, we explore the mechanism of H2O2 and blue light-induced apoptosis of ARPE-19 cells. Co-immunoprecipitation (Co-IP) is employed to test the interactions between proteins, and western blotting is used to detect the protein levels. Apoptosis is analyzed by Flow cytometry. Our results found that PRDX6 could interact with RARA in ARPE-19 cells, and H2O2 and blue light could significantly reduce the RARA protein expression, and also could inhibit the interaction between PRDX6 and RARA. Using a rescue experiment, we further elucidated that H2O2 and blue light reduced the RARA expression via down-regulating PRDX6. And H2O2 and blue light induced the ARPE-19 cell apoptosis via decreasing the expression of PRDX6. Our results suggested that the interaction between PRDX6 and RARA played important roles in the apoptosis of ARPE-19 cells.

A novel nonsense mutation in ADAMTS17 caused autosomal recessive inheritance Weill-Marchesani syndrome from a Chinese family.

Weill-Marchesani syndrome (WMS) is a rare connective tissue disorder characterized by short stature, brachydactyly, joint stiffness, eye anomalies, including microspherophakia, ectopia of the lenses, severe myopia, glaucoma and occasionally heart defects. Given these complex clinical manifestations and genetic heterogeneity, WMS patients presented misdiagnosed as high myopia or angle closure glaucoma. Here, we report ADAMTS17 mutations, a member of the extracellular matrix protease family, from a Chinese family. Patients have features that fall within the WMS spectrum. The exome (protein-coding regions of the genome) makes up ~1 % of the genome, it contains about 85% of known disease-related variants. Whole exome sequencing (WES) has been performed to identify the disease-associated genes, including one patient, his healthy sister, and his asymptomatic wife. Genome-wide homozygosity map was used to identify the disease caused locus. SNVs and INDELs were further predicted with MutationTaster, LRT, SIFT and SiPhy and compared to dbSNP150 and 1000 Genomes project. Filtered mutation was confirmed with Sanger sequencing in whole family members. The Genome-wide homozygosity map based on WES identified a total of 20 locus which were possible pathogenic. Further, a novel nonsense mutation c.1051A >T result in p.(lys351Ter) in ADAMTS17 had been identified in a candidate loci. The Sanger sequencing data has verified two consanguineous WMS patients in the family pedigree and revealed autosomal recessive (AR) inheritance pattern. The nonsense mutation in ADAMTS17 was analyzed in silico to explore its effects on protein function. We predicted the mutation produced non-function protein sequence. A novel nonsense mutation c.1051 A > T in ADAMTS17 had been identified caused autosomal recessive WMS in the Chinese family.

PRDX6 Protects ARPE-19 Cells from Oxidative Damage via PI3K/AKT Signaling.

BACKGROUND/AIMS: Oxidative stress that damages cells of the retinal pigment epithelium (RPE) can cause the development of hereditary retinal disease (HRD). PRDX6, which is a member of the PRDX family, is essential for removing metabolic free radicals from the body. However, the effect of PRDX6 on oxidative stress in HRD remains unknown. In this study, we sought to investigate the role of PRDX6 in oxidative stress-induced HRD in ARPE-19 cells and the molecular mechanism involved. METHODS: ARPE-19 cells were used in the current study. Intracellular ROS levels were determined by flow cytometry. Lipid peroxidation was measured using a commercial MDA assay kit. Cellular variability was determined by MTT assay. Apoptosis was determined using an Annexin V-FITC Apoptosis Detection Kit. mRNA and protein expression levels were detected by real-time PCR and western blot analysis, respectively. RESULTS: We found that H2O2 and blue light could induce significant oxidative stress damage and cell death in ARPE-19 cells. Furthermore, we found that PRDX6 levels significantly decreased after H2O2 treatment. PRDX6 overexpression protected ARPE-19 cells from H2O2- and blue light-induced oxidative damage, while PRDX6 knockdown enhanced oxidative damage in these cells. Mechanistically, we found that PRDX6 prevented oxidative damage and promoted ARPE-19 cell survival through the PI3K/AKT signaling pathway. CONCLUSIONS: Collectively, these results suggest that PRDX6 protects ARPE-19 cells from H2O2-induced oxidative stress and apoptosis and that this protection is mediated at least partially through the PI3K/AKT pathway.