4-hydroxy-2-nonenal and Retinal-Neovascularization

Reactive oxygen species (ROS), a by-product of oxygen metabolism mainly originating from mitochondria, participate in many pathological processes related to ophthalmopathy. Excessive production of ROS leads to oxidative stress, which influences the permeability, proliferation, migration, and tube formation of human retinal microcapillary endothelial cells (HRMECs). The molecular mechanisms underlying the effects of ROS are not clear. In Vldlr-/- mice, we used fundus fluorescein angiography and retinal flat mount staining to observe the effect of polypyrimidine tract-binding protein-associated splicing factor (PSF) on pathological retinal neovascularization in vivo. Additionally, in human retinal microvascular endothelial cells treated with 4-HNE, cell viability, tube formation, wound healing, and Transwell assays were performed to study the effect of PSF on the proliferation, migration, and tube formation of retinal vascular endothelial cells in vitro. Moreover, reactive oxygen species assay, real-time PCR, and Western blot were included to analyze the potential mechanism of PSF in the above series of effects. PSF ameliorated intraretinal neovascularization (IRNV) in vivo in Vldlr-/- mice. Under 4-hydroxynonenal (4-HNE) conditions in vitro, PSF reprogrammed mitochondrial bioenergetic and glycolytic profiles. It also reduced ROS levels and inhibited 4-HNE-induced angiogenesis, which involves the proliferation, migration, and tube formation of HRMECs. These results suggest that PSF participates in the regulation of HRMECs proliferation and migration during the development of pathological angiogenesis. We demonstrated that PSF enhanced Nrf2 activation and heme oxygenase-1 (HO-1) expression via extracellular signal-regulated kinase (ERK) and Akt signaling in HRMECs, which subsequently resulted in intracellular ROS scavenging. PSF restored endoplasmic reticulum (ER) redox homeostasis, which was indicated by an increase in protein disulfide isomerase (PDI) and Ero-1α and a reduction in GRP78 and C/EBP homologous protein (CHOP). PSF also attenuated ER stress via regulation of the protein kinase R (PKR)-like endoplasmic reticulum kinase PERK/eukaryotic translation factor 2 alpha (eIF2α)/activating transcription factor 4 (ATF4) pathway in 4-HNE-treated HRMECs. Our research shows that PSF may be a potential antioxidant that regulates pathological angiogenesis through ERK-AKT/Nrf2/HO-1 and PERK/eIF2α/ATF4 signal regulation. KEY MESSAGES: Reactive oxygen species (ROS

Topics: Activating Transcription Factor 4; Aldehydes; Animals; Cells, Cultured; eIF-2 Kinase; Endoplasmic Reticulum Stress; Endothelial Cells; Eukaryotic Initiation Factor-2; Extracellular Signal-Regulated MAP Kinases; Heme Oxygenase-1; Humans; Mice, Inbred C57BL; Mice, Knockout; Microvessels; Mitochondria; Proto-Oncogene Proteins c-akt; PTB-Associated Splicing Factor; Reactive Oxygen Species; Receptors, LDL; Retina; Retinal Neovascularization

Diabetic retinopathy (DR) is characterized by increased oxidative and nitrosative stress, both of which lead to neurotoxicity and vascular permeability. Previous studies on a variety of organs indicate that hydrogen-rich saline not only has considerable antioxidant and anti-inflammatory properties, but also suppresses oxidative stress-induced injury. In the present study, we assessed the effects of hydrogen-rich saline on neurovascular dysfunction and oxidative stress in an animal model (rat) of DR.. Male Sprague-Dawley rats with streptozotocin (STZ)-induced diabetes mellitus (DM) were injected intraperitoneally with 5 ml/kg hydrogen-saturated (experimental) or plain (control) saline daily for one month. Visual function and blood-retinal barrier (BRB) integrity were evaluated by electroretinography (ERG) and bovine serum albumin (BSA)-fluorescence, respectively. Histological changes in the inner retina were assessed by light microscopy. Biomarkers of oxidative stress, including 4-hydroxynonenal (4-HNE) and 8-hydroxy-2-deoxyguanosine (8-OH-dG), and antioxidant enzymes, including superoxide dismutase, glutathione peroxidase, glutathione reductase and glutathione transferase, were evaluated by ELISA. Synaptophysin and brain-derived neurotrophic factor (BDNF) levels were measured by immunoblotting.. STZ-diabetic rats were marked by clearly reduced b-wave amplitudes and oscillatory potentials, DM-related BRB breakdown and histological changes in the inner retina, all of which were suppressed following treatment with hydrogen-rich saline. Furthermore, hydrogen-rich saline reduced oxidative stress, increased antioxidant enzyme activities and preserved synaptophysin and BDNF levels in the diabetic rat retina.. Based on its inhibition of oxidative stress and up-regulation of anti-oxidative enzymes, we conclude that hydrogen-rich saline is a potentially valuable therapeutic modality for the treatment of DR.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aldehydes; Animals; Blood Glucose; Blood-Retinal Barrier; Blotting, Western; Body Weight; Brain-Derived Neurotrophic Factor; Deoxyguanosine; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Electroretinography; Enzyme-Linked Immunosorbent Assay; Male; Oxidative Stress; Oxidoreductases; Rats; Rats, Sprague-Dawley; Retinal Neovascularization; Sodium Chloride; Synaptophysin