bims-mideyd 2024-09-15 papers

Issue of 2024‒09‒15
four papers selected by
Rajalekshmy “Raji” Shyam, Indiana University Bloomington

Environ Toxicol. 2024 Sep 13.

The Novel Application of EUK-134 in Retinal Degeneration: Preventing Mitochondrial Oxidative Stress-Triggered Retinal Pigment Epithelial Cell Apoptosis by Suppressing MAPK/p53 Signaling Pathway.

Shang-Chun Tsou, Chen-Ju Chuang, Chin-Lin Hsu, Tzu-Chun Chen, Jui-Hsuan Yeh, Meilin Wang, Inga Wang, Yuan-Yen Chang, Hui-Wen Lin.

Age-related macular degeneration (AMD), a leading cause of blindness, is characterized by mitochondrial dysfunction of retinal pigment epithelium (RPE) cells. EUK-134 is a mimetic of SOD2 and catalase, widely used for its antioxidant properties in models of light-induced damage or oxidative stress. However, its effects on the retina are not yet clear. Here, we investigated the capability of EUK-134 in averting AMD using sodium iodate (NaIO3)-induced Balb/c mouse and ARPE-19 cells (adult RPE cell line). In vivo, EUK-134 effectively antagonized NaIO3-induced retinal deformation and prevented outer and inner nuclear layer thinning. In addition, it was found that the EUK-134-treated group significantly down-regulated the expression of cleaved caspase-3 compared with the group treated with NaIO3 alone. Our results found that EUK-134 notably improved cell viability by preventing mitochondrial ROS accumulation-induced membrane potential depolarization-mediated apoptosis in NaIO3-inducted ARPE-19 cells. Furthermore, we found that EUK-134 could inhibit p-ERK, p-p38, p-JNK, p-p53, Bax, cleaved caspase-9, cleaved caspase-3, and cleaved PARP by increasing Bcl-2 protein expression. Additionally, we employed MAPK pathway inhibitors by SB203580 (a p38 inhibitor), U0126 (an ERK inhibitor), and SP600125 (a JNK inhibitor) to corroborate the aforementioned observation. The results support that EUK-134 may effectively prevent mitochondrial oxidative stress-mediated retinal apoptosis in NaIO3-induced retinopathy.

Keywords: EUK‐134; MAPK signaling pathway; age‐related macular degeneration (AMD); retinal pigment epithelium (RPE); sodium iodate (NaIO3)

DOI: https://doi.org/10.1002/tox.24416

Int J Mol Sci. 2024 Aug 27. pii: 9267. [Epub ahead of print]25(17):

Galectin-1 Attenuates PDGF-Mediated AKT Signaling in Retinal Pigment Epithelial Cells.

Martina Bizzotto, Annabella Ostermaier, Caspar Liesenhoff, Wenxiu Ma, Arie Geerlof, Siegfried G Priglinger, Claudia S Priglinger, Andreas Ohlmann.

Galectins have the potential to interact with transmembrane glycoproteins to modulate their functions. Since galectin-1 interacts with PDGF-Rβ, we analyzed the effect of galectin-1 on PDGF-BB-mediated AKT signaling in primary human retinal pigment epithelial (RPE) cells and galectin-1-deficient immortalized human RPE cells (LGALS1-/-/ARPE-19) following incubation with PDGF-BB and galectin-1. Expression and localization of galectin-1, PDGF-Rβ and pAKT were investigated using western blot analysis and immunohistochemical staining. Cell proliferation of RPE cells was analyzed using BrdU ELISA. Following treatment of human RPE cells with human recombinant (hr)-galectin-1 and PDGF-BB, an intense clustering of PDGF-Rβ and colocalization with galectin-1 were detected. By Western blot analysis and immunocytochemistry of human RPE cells, an enhanced PDGF-BB-mediated expression of pAKT was observed, which was substantially reduced by additional incubation with hr-galectin-1. Vice versa, in LGALS1-/-/ARPE-19 cells, the PDGF-BB-induced pAKT signal was enhanced compared to wild-type cells. Furthermore, a decreased expression of PDGF-Rβ in human RPE cells was observed after treatment with PDGF-BB and hr-galectin-1, while in untreated LGALS1-/-/ARPE-19 cells, its constitutive expression was increased. In addition, after treatment of RPE cells with hr-galectin-1, the PDGF-BB-induced proliferation was markedly reduced. In summary, galectin-1 has the distinct potential to reduce PDGF-mediated pAKT signaling and proliferation in human RPE cells-an effect that is most likely facilitated via a decreased expression of PDGF-Rβ.

Keywords: AKT signaling; ARPE-19; ERK signaling; PDGF; PDGF-Rβ; galectin-1; galectin-1 deficiency; pAKT; pERK; retinal pigment epithelium cells

DOI: https://doi.org/10.3390/ijms25179267

Cells. 2024 Aug 27. pii: 1433. [Epub ahead of print]13(17):

Metformin Alleviates Inflammation and Induces Mitophagy in Human Retinal Pigment Epithelium Cells Suffering from Mitochondrial Damage.

Maija Toppila, Sofia Ranta-Aho, Kai Kaarniranta, Maria Hytti, Anu Kauppinen.

Mitochondrial malfunction, excessive production of reactive oxygen species (ROS), deficient autophagy/mitophagy, and chronic inflammation are hallmarks of age-related macular degeneration (AMD). Metformin has been shown to activate mitophagy, alleviate inflammation, and lower the odds of developing AMD. Here, we explored the ability of metformin to activate mitophagy and alleviate inflammation in retinal pigment epithelium (RPE) cells. Human ARPE-19 cells were pre-treated with metformin for 1 h prior to exposure to antimycin A (10 µM), which induced mitochondrial damage. Cell viability, ROS production, and inflammatory cytokine production were measured, while autophagy/mitophagy proteins were studied using Western blotting and immunocytochemistry. Metformin pre-treatment reduced the levels of proinflammatory cytokines IL-6 and IL-8 to 42% and 65% compared to ARPE-19 cells exposed to antimycin A alone. Metformin reduced the accumulation of the autophagy substrate SQSTM1/p62 (43.9%) and the levels of LC3 I and II (51.6% and 48.6%, respectively) after antimycin A exposure. Metformin also increased the colocalization of LC3 with TOM20 1.5-fold, suggesting active mitophagy. Antimycin A exposure increased the production of mitochondrial ROS (226%), which was reduced by the metformin pre-treatment (84.5%). Collectively, metformin showed anti-inflammatory and antioxidative potential with mitophagy induction in human RPE cells suffering from mitochondrial damage.

Keywords: AMD; RPE; autophagy; inflammation; metformin; mitochondrial ROS

DOI: https://doi.org/10.3390/cells13171433

Mol Med. 2024 Sep 09. 30(1): 142

Protective effect of ghrelin in oxidative stress-induced age-related macular degeneration in vitro and in vivo.

Jie Bai, Yanqing Wang, Yanze Li, Yan Liu, Shan Wang.

Oxidative damage to human retinal pigment epithelial (RPE) cells is the main cause of age-related macular degeneration (AMD), in our previous work, we showed that ghrelin has an antioxidative effect on human lens epithelium (HLE) cells, however, the studies of using ghrelin in treating the degenerative diseases of the retina have rarely been reported. In this article, we assessed the effect of ghrelin on preventing oxidative stress induced by hydrogen peroxide (H2O2) in ARPE-19 cells and its mechanism. We observed that pretreatment with ghrelin protected ARPE-19 cells from H2O2-induced cell oxidative injuries and apoptosis responses. Furthermore, an oxidative stress-induced mouse model of AMD was established via injection of sodium iodate (NaIO3) to tail veins, and treatment with ghrelin preserved retinal function, and protected photoreceptors.

Keywords: Age-related macular degeneration; Ghrelin; Oxidative stress; Vitro and vivo

DOI: https://doi.org/10.1186/s10020-024-00920-w