bims-mideyd 2025-02-02 papers

Antioxidants (Basel). 2025 Jan 15. pii: 92. [Epub ahead of print]14(1):

Cobalt Protoporphyrin Downregulates Hyperglycemia-Induced Inflammation and Enhances Mitochondrial Respiration in Retinal Pigment Epithelial Cells.

Peng-Hsiang Fang, Tzu-Yu Lin, Chiu-Chen Huang, Yung-Chang Lin, Cheng-Hung Lai, Bill Cheng.

Diabetic retinopathy is characterized by hyperglycemic retinal pigment epithelial cells that secrete excessive pro-inflammatory cytokines and VEGF, leading to retinal damage and vision loss. Cobalt protoporphyrin (CoPP) is a compound that can reduce inflammatory responses by inducing high levels of HO-1. In the present study, the therapeutic effects of CoPP were examined in ARPE-19 cells under hyperglycemia. ARPE-19 cells were incubated in culture media containing either 5.5 mM (NG) or 25 mM (HG) glucose, with or without the addition of 0.1 µM CoPP. Protein expressions in samples were determined by either Western blotting or immunostaining. A Seahorse metabolic analyzer was used to assess the impact of CoPP treatment on mitochondrial respiration in ARPE-19 cells in NG or HG media. ARPE-19 cells cultured in NG media displayed different cell morphology than those cultured in HG media. CoPP treatment induced high HO-1 expressions and significantly enhanced the viability of ARPE-19 cells under hyperglycemia. Moreover, CoPP significantly downregulated expressions of inflammatory and apoptotic markers and significantly upregulated mitochondrial respiration in APRPE-19 cells under hyperglycemia. CoPP treatment significantly enhanced cell viability in ARPE-19 cells under hyperglycemia. The treatment also downregulated the expressions of pro-inflammatory and upregulated mitochondrial respiration in the hyperglycemic cells.

Keywords: ARPE-19; cobalt protoporphyrin; diabetic retinopathy; hyperglycemia; mitochondria

DOI: https://doi.org/10.3390/antiox14010092

Invest Ophthalmol Vis Sci. 2025 Jan 02. 66(1): 63

CAMK2D and Complement Factor I-Involved Calcium/Calmodulin Signaling Modulates Sodium Iodate-Induced Mouse Retinal Degeneration.

Weixing Xu, Liu Cao, Hua Liu.

Purpose: To investigate the effect of Ca2+/calmodulin-dependent protein kinase II (CAMKII) δ subtypes (CAMK2D) on sodium iodate (NaIO3)-induced retinal degeneration in mice.
Methods: Bioinformatics analysis and Western blot experiments were used to screen the significantly differentially expressed genes in age-related macular degeneration (AMD) disease. CAMK2D knockdown and overexpression models were constructed by lentivirus (LV) infection of adult retinal pigment epithelial cell line-19 (ARPE-19) cells in vitro. Flow cytometry was used to detect ARPE-19 cell apoptosis induced by NaIO3. In vivo, CAMK2D knockdown and overexpression mouse models were generated by infecting mouse retinal pigment epithelium (RPE) with adeno-associated virus (AAV). Retinography, optical coherence tomography (OCT), and histological analysis (hematoxylin and eosin staining) were used to detect NaIO3-induced retinal structural changes in mice. Electroretinography (ERG) was used to detect NaIO3-induced retinal function changes in mice. TdT-mediated dUTP nick-end labeling (TUNEL) staining was used to detect the apoptosis of retinal cells induced by NaIO3. RNA sequencing (RNA-Seq) and bioinformatics analysis were used to screen for target genes affected by CAMK2D in CAMK2D-overexpressing ARPE-19 cells. And flow cytometry, OCT, and ERG were used to evaluate the regulatory effect of CAMK2D on target genes.
Results: Bioinformatics analysis found the expression of genes related to Ca2+ signal was significantly reduced in AMD patients. Western blot showed that in a mouse model of dry AMD induced by NaIO3, CAMK2D expression in RPE-Choroid tissue significantly lower than normal mice. In vitro, our results showed that overexpression of CAMK2D in ARPE-19 cells decreased apoptosis induced by NaIO3 and knockdown increased apoptosis. In vivo, CAMK2D overexpression in RPE cells can attenuate the retina degeneration induced by NaIO3 and CAMK2D knockdown aggravated degeneration. The bioinformatics analysis indicated that CAMK2D might affect AMD pathology through complement factor I (CFI). In vitro, knockdown of CFI in ARPE-19 cells increased apoptosis induced by NaIO3. In knockdown CFI ARPE-19 cells, overexpression of CAMK2D reduced the above apoptosis. In mice retina, CFI knockdown can aggravate the retina degeneration induced by NaIO3. In knockdown CFI mice, overexpression of CAMK2D in RPE can attenuate the above retina degeneration. Western blot confirmed that CAMK2D regulated the expression of CFI in mice.
Conclusions: CAMK2D can attenuate the retinal degeneration induced by NaIO3, which was achieved by regulating the CFI.

DOI: https://doi.org/10.1167/iovs.66.1.63

Cell Death Dis. 2025 Jan 27. 16(1): 49

Absent in melanoma 2: a potent suppressor of retinal pigment epithelial-mesenchymal transition and experimental proliferative vitreoretinopathy.

Yu Chen, Mingyuan Jiang, Liping Li, Shanshan Yang, Zuimeng Liu, Shiwen Lin, Wanxiao Wang, Jinyang Li, Feng Chen, Qiang Hou, Xiaoyin Ma, Ling Hou.

Epithelial-to-mesenchymal transition (EMT) is a critical and complex process involved in normal embryonic development, tissue regeneration, and tumor progression. It also contributes to retinal diseases, such as age-related macular degeneration (AMD) and proliferative vitreoretinopathy (PVR). Although absent in melanoma 2 (AIM2) has been linked to inflammatory disorders, autoimmune diseases, and cancers, its role in the EMT of the retinal pigment epithelium (RPE-EMT) and retinal diseases remains unclear. The present study demonstrated that AIM2 functions as a potent suppressor of RPE cell proliferation and EMT to maintain retinal homeostasis. Transcriptome analysis using RNA-sequencing (RNA-Seq) revealed that AIM2 was significantly downregulated in primary human RPE (phRPE) cells undergoing EMT and proliferation. Consequently, Aim2-deficient mice showed morphological changes and increased FN expression in RPE cells under physiological conditions, whereas AIM2 overexpression in phRPE cells inhibited EMT. In a retinal detachment-induced PVR mouse model, AIM2 deficiency promotes RPE-EMT, resulting in severe experimental PVR. Clinical samples further confirmed the downregulation of AIM2 in the PVR membranes from patients. Kyoto Encyclopedia of Genes and Genome analysis revealed that the PI3K-AKT signaling pathway was significantly related to RPE-EMT and that AIM2 inhibited AKT activation in RPE cells by reducing its phosphorylation. Moreover, treatment with eye drops containing an AKT inhibitor alleviated RPE-EMT and the severity of experimental PVR. These findings provide new insights into the complex mechanisms underlying RPE-EMT and PVR pathogenesis, with implications for rational strategies for potential therapeutic applications in PVR by targeting RPE-EMT.

DOI: https://doi.org/10.1038/s41419-025-07367-9

Front Nutr. 2024 ;11 1485466

Sulforaphane acutely activates multiple starvation response pathways.

Kendra S Plafker, Constantin Georgescu, Nathan Pezant, Atul Pranay, Scott M Plafker.

Sulforaphane (SFN) is an isothiocyanate derived from cruciferous vegetables that has demonstrated anti-cancer, anti-microbial and anti-oxidant properties. SFN ameliorates various disease models in rodents (e.g., cancer, diabetes, seizures) that are likewise mitigated by dietary restrictions leading us to test the hypothesis that this compound elicits cellular responses consistent with being a fasting/caloric restriction mimetic. Using immortalized human retinal pigment epithelial cells, we report that SFN impacted multiple nutrient-sensing pathways consistent with a fasted state. SFN treatment (i) increased mitochondrial mass and resistance to oxidative stress, (ii) acutely suppressed markers of mTORC1/2 activity via inhibition of insulin signaling, (iii) upregulated autophagy and further amplified autophagic flux induced by rapamycin or nutrient deprivation while concomitantly promoting lysosomal biogenesis, and (iv) acutely decreased glucose uptake and lactate secretion followed by an adaptive rebound that coincided with suppressed protein levels of thioredoxin-interacting protein (TXNIP) due to early transcriptional down-regulation. This early suppression of TXNIP mRNA expression could be overcome with exogenous glucosamine consistent with SFN inhibiting glutamine F6P amidotransferase, the rate limiting enzyme of the hexosamine biosynthetic pathway. SFN also altered levels of multiple glycolytic and tricarboxylic acid (TCA) cycle intermediates while reducing the inhibitory phosphorylation on pyruvate dehydrogenase, indicative of an adaptive cellular starvation response directing pyruvate into acetyl coenzyme A for uptake by the TCA cycle. RNA-seq of cells treated for 4 h with SFN confirmed the activation of signature starvation-responsive transcriptional programs. Collectively, these data support that the fasting-mimetic properties of SFN could underlie both the therapeutic efficacy and potential toxicity of this phytochemical.

Keywords: Sestrin 2; Txnip; autophagy; mTOR; starvation; sulforaphane

DOI: https://doi.org/10.3389/fnut.2024.1485466