Prevention of Cell Death by Activation of Hydroxycarboxylic Acid Receptor 1 (GPR81) in Retinal Explants.

ABSTRACT:

Background

Progressive retinal ganglion cell (RGC) dysfunction and death are common characteristics of retinal neurodegenerative diseases. Recently, hydroxycarboxylic acid receptor 1 (HCA₁R, GPR81) was identified as a key modulator of mitochondrial function and cell survival. Thus, we aimed to test whether activation of HCA₁R with 3,5-Dihydroxybenzoic acid (DHBA) also promotes RGC survival and improves energy metabolism in mouse retinas.

Methods

Retinal explants were treated with 5 mM of the HCA₁R agonist, 3,5-DHBA, for 2, 4, 24, and 72 h. Additionally, explants were also treated with 15 mM of L-glutamate to induce toxicity. Tissue survival was assessed through lactate dehydrogenase (LDH) viability assays. RGC survival was measured through immunohistochemical (IHC) staining. Total ATP levels were quantified through bioluminescence assays. Energy metabolism was investigated through stable isotope labeling and gas chromatography-mass spectrometry (GC-MS). Lactate and nitric oxide levels were measured through colorimetric assays.

Results

HCA₁R activation with 3,5-DHBAincreased retinal explant survival. During glutamate-induced death, 3,5-DHBA treatment also increased survival. IHC analysis revealed that 3,5-DHBA treatment promoted RGC survival in retinal wholemounts. 3,5-DHBA treatment also enhanced ATP levels in retinal explants, whereas lactate levels decreased. No effects on glucose metabolism were observed, but small changes in lactate metabolism were found. Nitric oxide levels remained unaltered in response to 3,5-DHBA treatment.

Conclusion

The present study reveals that activation of HCA₁R with 3,5-DHBA treatment has a neuroprotective effect specifically on RGCs and on glutamate-induced retinal degeneration. Hence, HCA₁R agonist administration may be a potential new strategy for rescuing RGCs, ultimately preventing visual disability.

SUBMITTER: Vohra R 

PROVIDER: S-EPMC9265426 | biostudies-literature |

REPOSITORIES: biostudies-literature