bims-mideyd 2024-02-18 papers

on Mitochondrial dysfunction in eye diseases

Issue of 2024–02–18
two papers selected by
Rajalekshmy “Raji” Shyam, Indiana University Bloomington

Ochratoxin A induces mitochondrial dysfunction, oxidative stress, and apoptosis of retinal ganglion cells (RGCs), leading to retinal damage in mice.
Clinically compliant cryopreservation of differentiated retinal pigment epithelial cells.

Int Ophthalmol. 2024 Feb 13. 44(1): 72

Ochratoxin A induces mitochondrial dysfunction, oxidative stress, and apoptosis of retinal ganglion cells (RGCs), leading to retinal damage in mice.

Miao Fu, Yuanyuan Chen, Anhuai Yang.

   PURPOSE: Ochratoxin A (OTA) contamination of food and feed is a serious problem worldwide. OTA is considered a carcinogen and immunotoxic, nephrotoxic, and neurotoxic mycotoxin. The present study aims to determine the toxic effects of OTA on retinal ganglion cells (RGCs) and assess the resulting impairment of retinal function in mice.
METHODS: RGC-5 cells were exposed to OTA (100 and 200 μg/L) for 3 days, and the mice were fed OTA-contain (100 and 200 μg/kg) diets for 4 weeks. Antioxidant indices were detected by spectrophotometer. The apoptosis of RGC-5 cells was determined by flow cytometry. Mitochondrial morphology and mitochondrial membrane potential were detected by immunofluorescence. RGC survival was determined by immunofluorescence staining with Brn3a. Flash electroretinography (ERG) was conducted to assess visual function.
RESULTS: The oxidative-antioxidant balance suggested that OTA-induced severe oxidative stress, including increased reactive oxygen species (ROS) and malondialdehyde (MDA) levels in the OTA-exposed RGC-5 cells, and the reduced activity of superoxide dismutase (SOD) and glutathione-S-transferase (GST) in the OTA exposed group. Furthermore, OTA exposure led to remarkable apoptosis in RGC-5 cells. The mitochondrial detection showed that OTA caused significant mitochondrial membrane potential reduction and mitochondrial fragmentation, which may be the cause of apoptosis of RGC-5 cells. Additionally, in vivo experiments demonstrated that OTA resulted in significant death of RGCs and subsequent retinal dysfunction in mice.
CONCLUSION: Ochratoxin A induces mitochondrial dysfunction, oxidative stress, and RGCs death in mice.

Keywords:  Apoptosis; Mitochondrial; Ochratoxin A; Oxidative stress; Retinal ganglion cells

DOI:  https://doi.org/10.1007/s10792-024-03032-w
Cytotherapy. 2024 Feb 13. pii: S1465-3249(24)00046-X. [Epub ahead of print]

Clinically compliant cryopreservation of differentiated retinal pigment epithelial cells.

Laura Baqué-Vidal, Heather Main, Sandra Petrus-Reurer, Alex R Lederer, Nefeli-Eirini Beri, Frederik Bär, Hugo Metzger, Cheng Zhao, Paschalis Efstathopoulos, Sarah Saietz, Andreas Wrona, Elham Jaberi, Hanni Willenbrock, Hazel Reilly, Mona Hedenskog, Elisabeth Moussaud-Lamodière, Anders Kvanta, J Carlos Villaescusa, Gioele La Manno, Fredrik Lanner.

   BACKGROUND AIMS: Age-related macular degeneration (AMD) is the most common cause of blindness in elderly patients within developed countries, affecting more than 190 million worldwide. In AMD, the retinal pigment epithelial (RPE) cell layer progressively degenerates, resulting in subsequent loss of photoreceptors and ultimately vision. There is currently no cure for AMD, but therapeutic strategies targeting the complement system are being developed to slow the progression of the disease.
METHODS: Replacement therapy with pluripotent stem cell-derived (hPSC) RPEs is an alternative treatment strategy. A cell therapy product must be produced in accordance with Good Manufacturing Practices at a sufficient scale to facilitate extensive pre-clinical and clinical testing. Cryopreservation of the final cell product is therefore highly beneficial, as the manufacturing, pre-clinical and clinical testing can be separated in time and location.
RESULTS: We found that mature hPSC-RPE cells do not survive conventional cryopreservation techniques. However, replating the cells 2-5 days before cryopreservation facilitates freezing. The replated and cryopreserved hPSC-RPE cells maintained their identity, purity and functionality as characteristic RPEs, shown by cobblestone morphology, pigmentation, transcriptional profile, RPE markers, transepithelial resistance and pigment epithelium-derived factor secretion. Finally, we showed that the optimal replating time window can be tracked noninvasively by following the change in cobblestone morphology.
CONCLUSIONS: The possibility of cryopreserving the hPSC-RPE product has been instrumental in our efforts in manufacturing and performing pre-clinical testing with the aim for clinical translation.

Keywords:  age-related macular degeneration; clinical translation; cryopreservation; manufacturing; retinal pigment epithelium

DOI:  https://doi.org/10.1016/j.jcyt.2024.01.014