bims-mideyd 2023-09-17 papers

bims-mideyd

Biomed News

on Mitochondrial dysfunction in eye diseases

Issue of 2023–09–17
six papers selected by
Rajalekshmy “Raji” Shyam, Indiana University Bloomington

Integration of human stem cell-derived in vitro systems and mouse preclinical models identifies complex pathophysiologic mechanisms in retinal dystrophy.
Insulin-like growth factor binding protein-3 mediates hyperosmolar stress-induced mitophagy through the mechanistic target of rapamycin.
OGD/R-induced ferroptosis and pyroptosis in retinal pigment epithelium cells: Role of PLD1 and PLD2 modulation.
Role of autophagy in stress and drug-responsive cell death in Entamoeba histolytica and its cross-talk with apoptosis-inducing factor.
Selective effects of estradiol on human corneal endothelial cells.
Identification and Analysis of Primary Cilia in the Corneal Endothelial Cells of Patients with Bullous Keratopathy.

Front Cell Dev Biol. 2023 ;11 1252547

Integration of human stem cell-derived in vitro systems and mouse preclinical models identifies complex pathophysiologic mechanisms in retinal dystrophy.

Melissa K Jones, Luz D Orozco, Han Qin, Tom Truong, Patrick Caplazi, Justin Elstrott, Zora Modrusan, Shawnta Y Chaney, Marion Jeanne.

  Rare DRAM2 coding variants cause retinal dystrophy with early macular involvement via unknown mechanisms. We found that DRAM2 is ubiquitously expressed in the human eye and expression changes were observed in eyes with more common maculopathy such as Age-related Macular Degeneration (AMD). To gain insights into pathogenicity of DRAM2-related retinopathy, we used a combination of in vitro and in vivo models. We found that DRAM2 loss in human pluripotent stem cell (hPSC)-derived retinal organoids caused the presence of additional mesenchymal cells. Interestingly, Dram2 loss in mice also caused increased proliferation of cells from the choroid in vitro and exacerbated choroidal neovascular lesions in vivo. Furthermore, we observed that DRAM2 loss in human retinal pigment epithelial (RPE) cells resulted in increased susceptibility to stress-induced cell death in vitro and that Dram2 loss in mice caused age-related photoreceptor degeneration. This highlights the complexity of DRAM2 function, as its loss in choroidal cells provided a proliferative advantage, whereas its loss in post-mitotic cells, such as photoreceptor and RPE cells, increased degeneration susceptibility. Different models such as human pluripotent stem cell-derived systems and mice can be leveraged to study and model human retinal dystrophies; however, cell type and species-specific expression must be taken into account when selecting relevant systems.

Keywords:  DRAM2; disease modeling; human stem cells; mouse models; retinal dystrophy; retinal organoids; single cell sequencing

DOI:  https://doi.org/10.3389/fcell.2023.1252547
J Biol Chem. 2023 Sep 08. pii: S0021-9258(23)02267-6. [Epub ahead of print] 105239

Insulin-like growth factor binding protein-3 mediates hyperosmolar stress-induced mitophagy through the mechanistic target of rapamycin.

Whitney Stuard Sambhariya, Ian J Trautmann, Danielle M Robertson.

Hyperosmolarity of the ocular surface triggers inflammation and pathological damage in dry eye disease (DED). In addition to a reduction in quality of life, DED causes vision loss and when severe, blindness. Mitochondrial dysfunction occurs as a consequence of hyperosmolar stress. We have previously reported on a role for the insulin-like growth factor binding protein-3 (IGFBP-3) in the regulation of mitochondrial ultrastructure and metabolism in mucosal surface epithelial cells; however, this appears to be context specific. Due to the finding that IGFBP-3 expression is decreased in response to hyperosmolar stress in vitro and in an animal model of DED, we next sought to determine whether the hyperosmolar stress-mediated decrease in IGFBP-3 alters mitophagy, a key mitochondrial quality control mechanism. Here we show that hyperosmolar stress induces mitophagy through differential regulation of BNIP3L/NIX and PINK1-mediated pathways. In corneal epithelial cells, this was independent of p62. The addition of exogenous IGFBP-3 abrogated the increase in mitophagy. This occurred through regulation of mTOR, highlighting the existence of a new IGFBP-3-mTOR signaling pathway. Together, these findings support a novel role for IGFBP-3 in mediating mitochondrial quality control in DED and have broad implications for epithelial tissues subject to hyperosmolar stress and other mitochondrial diseases.

DOI: https://doi.org/10.1016/j.jbc.2023.105239
Cell Biochem Funct. 2023 Sep 10.

OGD/R-induced ferroptosis and pyroptosis in retinal pigment epithelium cells: Role of PLD1 and PLD2 modulation.

Sun Young Park, He Mi Kang, Geuntae Park, Jin-Woo Oh, Young-Whan Choi.

  This study investigated the role of phospholipase D (PLD) in retinal ischemia-reperfusion (I/R) injury using an oxygen-glucose deprivation/reperfusion (OGD/R) model commonly used in retinal I/R injury research. To create an in vitro cellular I/R model, pharmacological inhibitors and small interfering RNA (siRNA) were used to target PLD1 and PLD2 in retinal pigment epithelial (RPE) cells. Treatment with PLD inhibitors and siRNA reduced reactive oxygen species (ROS) and malondialdehyde (MDA) induced by OGD/R in RPE cells and increased the levels of superoxide dismutase (SOD) and glutathione (GSH), indicating a reduction in oxidative damage and improvement in the antioxidant system. Next, we showed that inhibiting PLD1 or PLD2 reduced intracellular iron levels and lipid peroxidation, which are critical factors in ferroptosis. Additionally, PLD1 and PLD2 modulated the expression of proteins involved in the regulation of ferroptosis, including GPX4, SLC7A11, FTH1, and ACSL4. We also investigated the roles of PLD1 and PLD2 in preventing pyroptosis, another form of programmed cell death associated with inflammation. Our study found that OGD/R significantly increased the production of pro-inflammatory cytokines and activated caspase-1, NLRP3, ASC, cleaved-caspase 1 (C-caspase-1), and GSDMD-N in RPE cells, indicating pyroptosis induction. However, PLD1 and PLD2 inhibition or knockdown significantly inhibited the production of pro-inflammatory cytokines and activation of the NLRP3 inflammasome, Taken together, our findings support the hypothesis that the PLD signaling pathway plays a key role in OGD/R-induced ferroptosis and pyroptosis induction and may be a potential therapeutic target for preventing or treating retinal dysfunction and degeneration.

Keywords:  OGD/R; PLD; ferroptosis; pyroptosis; retinal pigment epithelium

DOI:  https://doi.org/10.1002/cbf.3848
Mol Biochem Parasitol. 2023 Sep 12. pii: S0166-6851(23)00051-8. [Epub ahead of print]256 111593

Role of autophagy in stress and drug-responsive cell death in Entamoeba histolytica and its cross-talk with apoptosis-inducing factor.

Anwesha Bandyopadhyay, Sudip Kumar Ghosh.

  Cell death in unicellular protozoan parasite Entamoeba histolytica is not yet reported though it displays several features of autophagic cell death. Autophagic cell death was reported to take place in ancient protozoans under several stresses. Here we report the occurrence of autophagic cell death in the Entamoeba histolytica trophozoites under oxidative stress as well as by the treatment with metronidazole, the most-widely-used drug for amoebiasis treatment and was shown to generate oxidative stress in the trophozoites. The autophagic flux increases during nutrient deprivation and metronidazole treatment and decreases upon oxidative stress. During oxidative stress the autophagy leads to nucleophagy that is ultimately destined to be digested within the lysosomal chamber. The formation of nucleophagosome depends on the apoptosis-inducing factor (AIF) that translocates to the nucleus from cytoplasm upon oxidative stress. It was experimentally proved that ATG8 (Autophagy-related protein 8) binds with the AIF in the nucleus of the trophozoites and helps in ATG8 recruitment and autophagy initiation overall suggesting that oxidative stress-driven AIF translocation to nucleus results in binding with ATG8 and initiates nucleophagy leading to cell death.

Keywords:  AIF; Autophagy; Entamoeba; Metronidazole; Nucleophagy

DOI:  https://doi.org/10.1016/j.molbiopara.2023.111593
Sci Rep. 2023 Sep 15. 13(1): 15279

Selective effects of estradiol on human corneal endothelial cells.

Seoyoung Han, Christian Mueller, Caitlin Wuebbolt, Sean Kilcullen, Varinda Nayyar, Brayan Calle Gonzalez, Ali Mahdavi Fard, Jamie C Floss, Michael J Morales, Sangita P Patel.

In Fuchs endothelial corneal dystrophy (FECD), mitochondrial and oxidative stresses in corneal endothelial cells (HCEnCs) contribute to cell demise and disease progression. FECD is more common in women than men, but the basis for this observation is poorly understood. To understand the sex disparity in FECD prevalence, we studied the effects of the sex hormone 17-β estradiol (E2) on growth, oxidative stress, and metabolism in primary cultures of HCEnCs grown under physiologic ([O2]2.5) and hyperoxic ([O2]A) conditions. We hypothesized that E2 would counter the damage of oxidative stress generated at [O2]A. HCEnCs were treated with or without E2 (10 nM) for 7-10 days under both conditions. Treatment with E2 did not significantly alter HCEnC density, viability, ROS levels, oxidative DNA damage, oxygen consumption rates, or extracellular acidification rates in either condition. E2 disrupted mitochondrial morphology in HCEnCs solely from female donors in the [O2]A condition. ATP levels were significantly higher at [O2]2.5 than at [O2]A in HCEnCs from female donors only, but were not affected by E2. Our findings demonstrate the resilience of HCEnCs against hyperoxic stress. The effects of hyperoxia and E2 on HCEnCs from female donors suggest cell sex-specific mechanisms of toxicity and hormonal influences.

DOI: https://doi.org/10.1038/s41598-023-42290-z
Curr Eye Res. 2023 Sep 14. 1-9

Identification and Analysis of Primary Cilia in the Corneal Endothelial Cells of Patients with Bullous Keratopathy.

Hideto Deguchi, Hidetoshi Tanioka, Mako Watanabe, Noriko Horiuchi, Hideki Fukuoka, Osamu Hieda, Tsutomu Inatomi, Shigeru Kinoshita, Chie Sotozono.

   PURPOSE: To identify primary cilia in human corneal endothelial cells (CECs) obtained from patients with bullous keratopathy (BK).
METHODS: This study involved CEC specimens obtained from 10 eyes of 10 consecutive patients (3 males and 7 females; mean age: 74.5 years, range: 68-90 years) with BK who underwent Descemet's stripping automated endothelial keratoplasty at Baptist Eye Institute, Kyoto, Japan between August 2019 and September 2020. Three corneal buttons obtained from 3 patients who underwent penetrating keratoplasty for keratoconus were used as 'non-BK' controls. All specimens were evaluated with immunofluorescence staining using an antibody against acetylated α-tubulin.
RESULTS: Ciliary expression was observed in 6 of the 10 CEC specimens; i.e., in 2 specimens obtained from BK patients after glaucoma surgery (trabeculectomy), in 2 specimens obtained from patients with Fuchs endothelial corneal dystrophy, and in 2 specimens obtained from a patient with BK after laser iridotomy for primary angle closure. There was acetylated α-tubulin staining but no hair-like structures in 2 specimens, and ciliary expression was unknown in 2 specimens due to the absence of cells. The length of the primary cilia varied between all specimens. In contrast, no primary cilia were observed in the corneal buttons obtained from the 3 keratoconus patients.
CONCLUSION: The findings in this study clearly demonstrate the expression of primary cilia in the CECs of patients afflicted with BK.

Keywords:  DSAEK; bullous keratopathy; corneal endothelial cells; primary cilia

DOI:  https://doi.org/10.1080/02713683.2023.2259633