Crocetin Prevents RPE Cells from Oxidative Stress through Protection of Cellular Metabolic Function and Activation of ERK1/2

Abstract

Age-related macular degeneration (AMD) is a leading cause for visual impairment in aging populations with limited established therapeutic interventions available. Oxidative stress plays an essential role in the pathogenesis of AMD, damaging the retinal pigment epithelium (RPE), which is essential for the function and maintenance of the light-sensing photoreceptors. This study aimed to evaluate the effects of crocetin, one of the main components of Saffron, on an in vitro RPE model of tert-butyl hydroperoxide (TBHP) induced oxidative stress using ARPE19 cells. The effects of crocetin were assessed using lactate de-hydrogenase (LDH) and ATP assays, as well as immunocytochemistry for cell morphology, junctional integrity, and nuclear morphology. The mechanism of crocetin action was determined via assessment of energy production pathways, including mitochondrial respiration and glycolysis in real-time as well as investigation of extracellular signal-regulated kinase 1/2 (ERK1/2) activation and distribution. Our results show that crocetin pre-treatment protects ARPE19 cells from TBHP-induced LDH release, intracellular ATP depletion, nuclear condensation, and disturbance of junctional integrity and cytoskeleton. The protective effect of crocetin is mediated via the preservation of energy production pathways and activation of ERK1/2 in the first minutes of TBHP exposure to potentiate survival pathways. The combined data suggest that a natural antioxidant, such as crocetin, represents a promising candidate to prevent oxidative stress in RPE cells and might halt or delay disease progression in AMD.

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“…In this model, neuroprotection by saffron was associated with a reduction of intracellular calcium increase induced by ATP and was mediated through saffron action on the purinergic P2X7 receptor [ 83 ]. In parallel, it has been shown in vitro as well that crocetin reduces the effects of oxidative stress induced by tert -butyl-hydroperoxide in the ARPE-19 cell line [ 84 ]. Pretreatment of RPE cells with crocetin prevented apoptosis evidenced by lactate dehydrogenase release, intracellular ATP depletion, and nuclear condensation [ 84 ].…”

“…In parallel, it has been shown in vitro as well that crocetin reduces the effects of oxidative stress induced by tert -butyl-hydroperoxide in the ARPE-19 cell line [ 84 ]. Pretreatment of RPE cells with crocetin prevented apoptosis evidenced by lactate dehydrogenase release, intracellular ATP depletion, and nuclear condensation [ 84 ]. Crocetin preserved junctional and cytoskeleton integrity that are essential for RPE functionality [ 84 ].…”

“…Pretreatment of RPE cells with crocetin prevented apoptosis evidenced by lactate dehydrogenase release, intracellular ATP depletion, and nuclear condensation [ 84 ]. Crocetin preserved junctional and cytoskeleton integrity that are essential for RPE functionality [ 84 ]. The neuroprotective effect of saffron components could also be related to their known anti-inflammatory properties.…”

Crocetin and Its Glycoside Crocin, Two Bioactive Constituents From Crocus sativus L. (Saffron), Differentially Inhibit Angiogenesis by Inhibiting Endothelial Cytoskeleton Organization and Cell Migration Through VEGFR2/SRC/FAK and VEGFR2/MEK/ERK Signaling Pathways

“…Anti-VEGF agents are currently used for the treatment of CNV in AMD. Interestingly, a recent study showed that saffron extract ameliorated the retinal degenerative processes in AMD patients, possibly through neuroprotective activities (Di Marco et al, 2019), while another study showed that crocetin prevented retinal pigment epithelia (RPE) from incurring oxidative stress- induced damage and might halt or delay AMD disease progression (Karimi et al, 2020). Additionally, lutein (another carotenoid) has been recommended as a health supplement for AMD patients by the NIH (Melendez-Martinez, 2019).…”

Correction: Karimi, P., et al. Crocetin Prevents RPE Cells from Oxidative Stress through Protection of Cellular Metabolic Function and Activation of ERK1/2. Int. J. Mol. Sci. 2020, 21, 2949

“…The authors wish to make the following correction to Figure 6B of this article [ 1 ]: the merge image of group “Pre 15min” (row 5, column 3) was also added by mistake as the merge image of group “TBHP only 15min” (row 3, column 3). The images of the DAPI and pERK1/2 single channels are correct for all experimental groups.…”