A time window for rescuing dying retinal ganglion cells

© 2024. The Author(s)..

BACKGROUND: Retinal ganglion cell (RGC) degeneration and death cause vision loss in patients with glaucoma. Regulated cell death, once initiated, is generally considered to be an irreversible process. Recently, we showed that, by timely removing the cell death stimulus, stressed neuronal PC12 cells can recover from phosphatidylserine (PS) exposure, nuclear shrinkage, DNA damage, mitochondrial fragmentation, mitochondrial membrane potential loss, and retraction of neurites, all hallmarks of an activated cell death program. Whether the cell death process can be reversed in neurons of the central nervous system, like RGCs, is still unknown. Here, we studied reversibility of the activated cell death program in primary rat RGCs (prRGCs).

METHODS: prRGCs were exposed to ethanol (5%, vol/vol) to induce cell death. At different stages of the cell death process, ethanol was removed by washing and injured prRGCs were further cultured in fresh medium to see whether they recovered. The dynamics of single cells were monitored by high-resolution live-cell spinning disk microscopy. PS exposure, mitochondrial structure, membrane potential, and intracellular Ca2+ were revealed by annexin A5-FITC, Mito-tracker, TMRM, and Fluo 8-AM staining, respectively. The distribution of cytochrome c was investigated by immunofluorescence. The ultrastructure of mitochondria was studied by electron microscopy.

RESULTS: Analysis of temporal relationships between mitochondrial changes and PS exposure showed that fragmentation of the mitochondrial network and loss of mitochondrial membrane potential occurred before PS exposure. Mitochondrial changes proceeded caspase-independently, while PS exposure was caspase dependent. Interestingly, prRGCs recovered quickly from these mitochondrial changes but not from PS exposure at the plasma membrane. Correlative light and electron microscopy showed that stress-induced decrease in mitochondrial area, length and cristae number was reversible. Intracellular Ca2+ was elevated during this stage of reversible mitochondrial injury, but there was no sign of mitochondrial cytochrome c release.

CONCLUSIONS: Our study demonstrates that RGCs with impaired mitochondrial structure and function can fully recover if there is no mitochondrial cytochrome c release yet, and no PS is exposed at the plasma membrane. This finding indicates that there is a time window for rescuing dying or injured RGCs, by simply removing the cell death stimulus. Video Abstract.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:22

Enthalten in:

Cell communication and signaling : CCS - 22(2024), 1 vom: 31. Jan., Seite 88

Sprache:

Englisch

Beteiligte Personen:

You, Wenting [VerfasserIn]
Knoops, Kèvin [VerfasserIn]
Boesten, Iris [VerfasserIn]
Berendschot, Tos T J M [VerfasserIn]
van Zandvoort, Marc A M J [VerfasserIn]
Benedikter, Birke J [VerfasserIn]
Webers, Carroll A B [VerfasserIn]
Reutelingsperger, Chris P M [VerfasserIn]
Gorgels, Theo G M F [VerfasserIn]

Links:

Volltext

Themen:

3K9958V90M
9007-43-6
Caspases
Cytochrome c release
Cytochromes c
EC 3.4.22.-
Ethanol
Journal Article
Mitochondrial fragmentation
PS exposure
Primary RGCs
Research Support, Non-U.S. Gov't
Reversible cell death program
Video-Audio Media

Anmerkungen:

Date Completed 09.02.2024

Date Revised 20.03.2024

published: Electronic

Citation Status MEDLINE

doi:

10.1186/s12964-023-01427-3

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM367866382