bims-mideyd 2022-02-13 papers

on Mitochondrial dysfunction in eye diseases

Issue of 2022–02–13
two papers selected by
Rajalekshmy “Raji” Shyam, Indiana University Bloomington

Filtering blue light mitigates the deleterious effects induced by the oxidative stress in human retinal pigment epithelial cells.
Nicotinamide mononucleotide increases cell viability and restores tight junctions in high-glucose-treated human corneal epithelial cells via the SIRT1/Nrf2/HO-1 pathway.

Exp Eye Res. 2022 Feb 05. pii: S0014-4835(22)00059-8. [Epub ahead of print] 108978

Filtering blue light mitigates the deleterious effects induced by the oxidative stress in human retinal pigment epithelial cells.

Mohamed Abdouh, Melissa Lu, Yunxi Chen, Alicia Goyeneche, Julia Valdemarin Burnier, Miguel N Burnier.

  Age-related macular degeneration (AMD) is a major cause of blindness in elderly. It is characterized by the loss of central vision due to damaged retinal pigment epithelial (RPE) cells and photoreceptors. Blue Light (BL) exposure was proposed as a risk factor for AMD progression. We undertook this study to determine the effects of BL on the behaviour of RPE cells and their potential mitigation by BL-filtering intraocular lenses (IOL). Human RPE cells were exposed or not to BL, with the absence or presence of either a clear ultraviolet (UV)-filtering IOL (CIOL), or a yellow UV- and BL-filtering IOL (YIOL). Cells were analyzed for their oxidative stress by measuring the levels of reactive oxygen species (ROS), and their viability. BL exposure significantly increased the levels of both total cellular and mitochondrial ROS. While this increase was not affected by placing the CIOL in the BL beam, YIOL decreased the levels of both ROS reservoirs. Increased ROS production was accompanied by increased cell death which was similarly decreased when cells were protected with the YIOL. Pre-treatment of cells with N-acetylcycteine (NAC) abolished the increased cell death, suggesting that the effects of BL on cell viability were mainly due to increased levels of ROS. BL is deleterious to RPE cells due to increased oxidative stress and cell death. These effects were mitigated by filtering these radiations. The use of BL-filtering devices may represent a strategy to reduce these effects on RPE cells and delay the onset of AMD.

Keywords:  Blue light; Intraocular lens; Oxidative stress; Retinal pigment epithelial cells

DOI:  https://doi.org/10.1016/j.exer.2022.108978
Biomed Pharmacother. 2022 Feb 02. pii: S0753-3322(22)00047-6. [Epub ahead of print]147 112659

Nicotinamide mononucleotide increases cell viability and restores tight junctions in high-glucose-treated human corneal epithelial cells via the SIRT1/Nrf2/HO-1 pathway.

Qi Pu, Xiao-Xiao Guo, Jing-Jie Hu, Ao-Ling Li, Gui-Gang Li, Xin-Yu Li.

   BACKGROUND: Diabetes mellitus (DM)-related corneal epithelial dysfunction is a severe ocular disorder; however, the effects of nicotinamide mononucleotide (NMN) on high-glucose (HG)-treated human corneal epithelial cells (HCECs) remain unclear.
METHODS: We conducted an in-vitro study to examine the effects of NMN treatment on HG-treated HCECs. Cell viability was measured using trypan blue stain, mitochondrial membrane potential was measured using JC-1 stain, and intracellular reactive oxygen species and apoptosis assays were conducted using flow cytometry. Transepithelial electrical resistance (TEER) and zonula occludens-1 (ZO-1) immunofluorescence for tight junction examinations were conducted. Immunoblot analyses were conducted to analyze the expression of silent information regulator-1 (SIRT1), nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) of the SIRT1/Nrf2/HO-1 pathway.
RESULTS: NMN increased cell viability by reducing cell damage, reducing apoptosis, increasing cell migration, and restoring tight junctions in HG-treated HCECs. By analyzing the expressions of SIRT1, Nrf2, HO-1, NMN demonstrated protective effects via the SIRT1/Nrf2/HO-1 pathway.
CONCLUSIONS: NMN increases cell viability by reversing cell damage, reducing apoptosis, increasing cell migration, and restoring tight junctions in HG-treated HCECs, and these effects may be mediated by the SIRT1/Nrf2/HO-1 pathway.

Keywords:  Corneal epithelial cell; Diabetes mellitus; Heme oxygenase-1; Nicotinamide mononucleotide; Nuclear factor erythroid 2-related factor 2; Silent information regulator-1

DOI:  https://doi.org/10.1016/j.biopha.2022.112659