salvianolic-acid-a and Macular-Degeneration

Salvianolic acid A (Sal A), an active monomer of Salvia miltiorrhiza, is a phenolic carboxylic acid derivative. The present study was performed to investigate the underlying mechanism of the anti-inflammation effect of Sal A, especially focusing on mTOR-KEAP1-Nrf2 and P2X7R-PKR-NLRP3 signaling pathways.. SD mice were divided into four groups: PBS, oxidized-low density lipoprotein (ox-LDL, 3 mg/kg), and ox-LDL (3 mg/kg) + Sal A (5 mg/kg) and + Sal A (10 mg/ml) groups. In in vitro experiments, ARPE-19 cells were cultured with serum free medium (SFM) or ox-LDL (100 mg/L), with or without Sal A (5 µM/50 µM) for 24 hours.. Sal A attenuated ox-LDL-induced lipidosis and apoptosis in the retinal pigment epithelium (RPE) layer. Ox-LDL elevated ROS level and induced RPE inflammation, which were inhibited by Sal A pretreatment. Sal A activated PI3K/AKT/mTOR signaling pathway, which further promoted the disassociation of Keap1-Nrf2 complex and the phosphorylation of Nrf2. PI3K and mTOR chemical inhibitors abolished Sal A-induced Nrf2 activation while it had no influence on nlrp3 expression. Sal A also inhibited RPE inflammation by inactivating the P2x7r-Pkr-Nlrp3 signaling pathway.. The above results indicate that Sal A protects RPE from lipid oxidative damage and chronic inflammation through up-regulating Nrf2 and inactivating the P2x7r-Pkr-Nlrp3 signaling pathway.

Topics: Animals; Apoptosis; Blotting, Western; Caffeic Acids; Cell Line; Cell Survival; Enzyme-Linked Immunosorbent Assay; Immunohistochemistry; Immunoprecipitation; In Situ Nick-End Labeling; Lactates; Lipoproteins, LDL; Macular Degeneration; Male; Mice; Oxidative Stress; Proto-Oncogene Proteins c-akt; Rats, Sprague-Dawley; Reactive Oxygen Species; Retinal Pigment Epithelium; Signal Transduction

Age-related macular degeneration is closely related to lipid oxidation, while relationship between OX-LDL and choroidal neovascularization is unclear. Recently, cylindromatosis is proved to regulate angiogenesis. However, its role in CNV progression remained unclear. Salvianolic acid A is widely used in vascular diseases. We investigated the relationship between OX-LDL and CNV and explore antineovascularization mechanism of Sal A.. C57BL6/J mice were randomized into four groups and injected with PBS or OX-LDL, together with Sal A for one week. CNV was induced by laser; CNV severity was analyzed by fundus fluorescein angiography, H&E staining, and choroid flat mount after 1 week. In in vitro experiments, ARPE-19 and HUVECs were cultured with OX-LDL (with or without Sal A) for 48 hours. Angiogenic proteins, cell junction integrity, and tube formation were measured.. OX-LDL promoted laser-induced CNV volume by increasing VEGF, PDGF, and CYLD levels. Sal A antagonized OX-LDL effects and restrained CNV progression by decreasing VEGF/PDGF/CYLD, increasing antiangiostatin levels, and promoting P62-CYLD-TRAF6 interaction.. We demonstrated oxidation damage exacerbates CNV progression, and Sal A could be a clinical therapeutic reagent to exudative AMD.

Topics: Animals; Caffeic Acids; Choroidal Neovascularization; Down-Regulation; Humans; Lactates; Lipoproteins, LDL; Macular Degeneration; Mice; Mice, Inbred C57BL

Reactive oxygen species (ROS) impair the physiological functions of retinal pigment epithelial (RPE) cells, which is known as one major cause of age-related macular degeneration. Salvianolic acid A (Sal A) is the main effective aqueous extract of Salvia miltiorrhiza. The aim of this study was to test the potential role of Sal A against oxidative stress in cultured RPE cells and to investigate the underlying mechanistic signaling pathways. We observed that Sal A significantly inhibited hydrogen peroxide (H2O2)-induced primary and transformed RPE cell death and apoptosis. H2O2-stimulated mitogen-activated protein kinase activation, ROS production, and subsequent proapoptotic AMP-activated protein kinase activation were largely inhibited by Sal A. Further, Sal A stimulation resulted in a fast and dramatic activation of Akt/mammalian target of rapamycin complex 1 (mTORC1) signaling, followed by phosphorylation, accumulation, and nuclear translocation of the NF-E2-related factor 2 (Nrf2), along with increased expression of the antioxidant-response element-dependent gene heme oxygenase-1 (HO-1). Both Nrf2 and HO-1 were required for Sal A-mediated cytoprotective effect, as Nrf2/HO-1 inhibition abolished Sal A-induced beneficial effects against H2O2. Meanwhile, the PI3K/Akt/mTORC1 chemical inhibitors not only suppressed Sal A-induced Nrf2/HO-1 activation, but also eliminated its cytoprotective effect in RPE cells. These observations suggest that Sal A activates the Nrf2/HO-1 axis in RPE cells and protects against oxidative stress via activation of Akt/mTORC1 signaling.

Topics: Animals; Apoptosis; Caffeic Acids; Heme Oxygenase-1; Lactates; Macular Degeneration; Mechanistic Target of Rapamycin Complex 1; Membrane Proteins; Multiprotein Complexes; NF-E2-Related Factor 2; Oxidative Stress; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; Retinal Pigment Epithelium; Signal Transduction; TOR Serine-Threonine Kinases