Abstract
Purpose :
Peptide Lv (PLv) is a small (~40 amino acids) endogenous secretory peptide expressed in various organs including the retina, vascular endothelium, and brain. Peptide Lv augments the protein expression and current densities of the L-type voltage-gated calcium channels in photoreceptors. As a newly identified bioactive peptide, our understanding of its diverse functions is still evolving. To further elucidate the potential roles of PLv in the eye, we examined the longitudinal changes in the neural and vascular retinas in PLv null (PLv-/-) mice.
Methods :
At different ages (2, 3, 6, 9, 12, and 15 months old), PLv-/- and age-matched control (PLv+/+) littermates were examined in vivo using electroretinogram recordings (ERG) and fluorescein angiography. Dark-adapted retinal light responses were recorded with light flashes of 0.1, 0.3, 1.0, 3.0,10 and 25 cd.s/m2 intensities. Mice were injected intraperitoneally with 10% sodium fluorescein (2 μL/g body weight) and the retinal vasculature was imaged under a blue-fluorescent illumination, 5 minutes post injection. The mice eyes were then enucleated, fixed with 4% paraformaldehyde, and processed for histological sections stained with H&E for retinal morphometric analyses.
Results :
At 2 months old, PLv-/- mice had smaller dark-adapted ERG amplitudes compared to age-matched controls, but there was no difference in retinal microvascular densities between PLv-/- and the controls. However, by 3 months old, the retinas of PLv-/- mice were thinner than the controls particularly at the photoreceptor (inner segment/outer nuclear) and inner nuclear layers.
Conclusions :
Peptide Lv deficiency is not fatal, but PLv might be indispensable in maintaining the structural and functional integrity of the retina.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.