Effects of Bevacizumab, Ranibizumab, and Aflibercept on MicroRNA Expression in a Retinal Pigment Epithelium Cell Culture Model of Oxidative Stress

Deciphering the role of miR-71 and let-7 in the fertility of cystic echinococcosis cysts: a preliminary assessment

Cystic echinococcosis (CE) is a neglected helminthic zoonosis in many parts of the world. Some CE cysts in the intermediate host are non-fertile. Considering the function of microRNAs in many biological processes such as embryonic development, cell proliferation, and apoptosis, this study investigated the function and comparison of miR-71 and let-7 in fertile and non-fertile CE cysts. Here, we determined the expression level of the miRNAs for 33 animal cysts and 16 human cysts (Echinococcus granulosus sensu stricto (G1). The quantitative real-time PCR method was conducted for the expression evaluation of miR-71 and let-7. The expression of both miRNAs in all samples was determined using the following formula: [ΔCT = CT (target) - CT (internal control)]. A comparison of Δct of miR-71 and let-7 in fertile and non-fertile cysts did not show a significant difference (P = 0.911 and 0.354). In cattle, sheep, and humans, Δct of miR-71, and let-7 were higher, respectively. Therefore, the mean expression of miR-71 and let-7 indicates an increase in humans compared to other intermediate hosts. Also, statistical results show a significant difference in the expression of these miRNAs in sheep, cattle, and human cysts (P = 0.025 and 0.01). The lower expression of these miRNAs in cattle cysts and their common infertility might be associated with the hypothesis and function of miRNAs in the fertility of CE cysts. So we should not ignore the function and role of miRNAs in this subject due to the importance of infertility in E. granulosus epidemiology.

Anti-VEGF Drugs Influence Epigenetic Regulation and AMD-Specific Molecular Markers in ARPE-19 Cells

Our study assesses the effects of anti-VEGF (Vascular Endothelial Growth Factor) drugs and Trichostatin A (TSA), an inhibitor of histone deacetylase (HDAC) activity, on cultured ARPE-19 (Adult Retinal Pigment Epithelial-19) cells that are immortalized human retinal pigment epithelial cells. ARPE-19 cells were treated with the following anti-VEGF drugs: aflibercept, ranibizumab, or bevacizumab at 1× and 2× concentrations of the clinical intravitreal dose (12.5 μL/mL and 25 μL/mL, respectively) and analyzed for transcription profiles of genes associated with the pathogenesis age-related macular degeneration (AMD). HDAC activity was measured using the Fluorometric Histone Deacetylase assay. TSA downregulated HIF-1α and IL-1β genes, and upregulated BCL2L13, CASPASE-9, and IL-18 genes. TSA alone or bevacizumab plus TSA showed a significant reduction of HDAC activity compared to untreated ARPE-19 cells. Bevacizumab alone did not significantly alter HDAC activity, but increased gene expression of SOD2, BCL2L13, CASPASE-3, and IL-18 and caused downregulation of HIF-1α and IL-18. Combination of bevacizumab plus TSA increased gene expression of SOD2, HIF-1α, GPX3A, BCL2L13, and CASPASE-3, and reduced CASPASE-9 and IL-β. In conclusion, we demonstrated that anti-VEGF drugs can: (1) alter expression of genes involved in oxidative stress (GPX3A and SOD2), inflammation (IL-18 and IL-1β) and apoptosis (BCL2L13, CASPASE-3, and CASPASE-9), and (2) TSA-induced deacetylation altered transcription for angiogenesis (HIF-1α), apoptosis, and inflammation genes.

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.

miR302a and 122 are deregulated in small extracellular vesicles from ARPE-19 cells cultured with H2O2

Age related macular degeneration (AMD) is a common retina-related disease leading to blindness. Little is known on the origin of the disease, but it is well documented that oxidative stress generated in the retinal pigment epithelium and choroid neovascularization are closely involved. The study of circulating miRNAs is opening new possibilities in terms of diagnosis and therapeutics. miRNAs can travel associated to lipoproteins or inside small Extracellular Vesicles (sEVs). A number of reports indicate a significant deregulation of circulating miRNAs in AMD and experimental approaches, but it is unclear whether sEVs present a significant miRNA cargo. The present work studies miRNA expression changes in sEVs released from ARPE-19 cells under oxidative conditions (i.e. hydrogen peroxide, H₂O₂). H₂O₂ increased sEVs release from ARPE-19 cells. Moreover, 218 miRNAs could be detected in control and H₂O₂ induced-sEVs. Interestingly, only two of them (hsa-miR-302a and hsa-miR-122) were significantly under-expressed in H₂O₂-induced sEVs. Results herein suggest that the down regulation of miRNAs 302a and 122 might be related with previous studies showing sEVs-induced neovascularization after oxidative challenge in ARPE-19 cells.

The effect of albendazole sulfoxide on the expression of miR-61 and let-7 in different in vitro developmental stages of Echinococcus granulosus

Albendazole, as the main anti-echinococcal benzimidazole, has demonstrated safe and effective therapeutic outcomes in the treatment of echinococcosis. The emergence of resistance or reduced response to albendazole sulfoxide (ABZ_SOX) and other benzimidazoles have been demonstrated in several parasitic helminths of medical and veterinary importance. As the genetic makeup and miRNA profile of helminths affects their response to albendazole sulfoxide, the present study was conducted to investigate the expression of miRNAs in different developmental stages of Echinococcus granulosus exposed to albendazole sulfoxide in vitro. Different developmental stages of the helminth were obtained from in vitro cultured E. granulosus in monophasic and diphasic media. In both ABZ-SOX-treated and control parasites miRNAs were extracted from microcysts, intact protoscoleces and strobilated worms with one and three segments. Expression of two miRNAs, let-7 and miR-61 was evaluated using RT-qPCR for each stage. Results of the present study revealed significant differential expression of both let-7 and miR-61 at different drug concentrations. A significant difference of let-7 expression was observed between the strobilated and metacestode stages of E. granulosus exposed to ABZ-SOX. In the treated protoscoleces, let-7 expression was significantly reduced in the presence of ABZ-SOX at 1000 μg/ml concentration. In contrast higher expression levels were documented in the segmented worms. In the microcysts exposed to different drug concentrations a significant decline of miR-61 expression was demonstrated. Also, a significant increase in expression of miR-61 was observed in one proglottid worms as well as the protoscoleces. Under high drug concentration or long-term exposure of the protoscoleces to ABZ-SOX significantly higher miR-61 expression was observed compared to the controls. Our findings suggested that under in vitro benzimidazole exposure the expression of two E. granulosus miRNAs were significantly affected in the microcyst stage. This study presents the first evidence of the nature of benzimidazole effects on miRNA expression in platyhelminths.

S-Allylmercapro-N-Acetylcysteine Attenuates the Oxidation-Induced Lens Opacification and Retinal Pigment Epithelial Cell Death In Vitro

The capacity of S-Allylmercapto-N-acetylcysteine (ASSNAC) to protect human retinal pigment epithelial (RPE) cells (line ARPE-19) and porcine lenses from oxidative stress was studied. Confluent ARPE-19 cultures were incubated with ASSNAC or N-acetyl-cysteine (NAC) followed by exposure to oxidants and glutathione level and cell survival were determined. Porcine lenses were incubated with ASSNAC and then exposed to H₂O₂ followed by lens opacity measurement and determination of glutathione (reduced (GSH) and oxidized (GSSG)) in isolated lens adhering epithelial cells (lens capsule) and fiber cells consisting the lens cortex and nucleus (lens core). In ARPE-19 cultures, ASSNAC (0.2 mM; 24 h) increased glutathione level by 2–2.5-fold with significantly higher increase in GSH compared to NAC treated cultures. Similarly, ex-vivo exposure of lenses to ASSNAC (1 mM) significantly reduced the GSSG level and prevented H₂O₂ (0.5 mM)-induced lens opacification. These results demonstrate that ASSNAC up-regulates glutathione level in RPE cells and protects them from oxidative stress-induced cell death as well as protects lenses from oxidative stress-induced opacity. Further validation of these results in animal models may suggest a potential use for ASSNAC as a protective therapy in retinal degenerative diseases as well as in attenuation of oxidative stress-induced lens opacity.