Fig. 2

Increased lactate production in rods with chronically active HIFs. a Expression of the lactate sensor Laconic in photoreceptors after subretinal AAV application. Scale bar, 50 \(\upmu\)m. b Preparation of acute retinal slices from flat mounted half retinas and imaging of Laconic by TPLSM. c Schematic representation of monocarboxylate transporter (MCT) trans-acceleration with high extracellular levels of oxamate causing export of lactate. d Laconic raw FRET signal (individual values and means ± SD) in PRs at baseline (BL) and at minimum (MIN) obtained after exposure to oxamate (orange; 6 retinal slices from 2 mice) or to aglycemic medium (blue; 11 retinal slices from 4 mice). e Laconic traces (mean ± SD) in PRs of \(rod^{\varDelta \ Vhl}\) (orange; 19 retinal slices from 10 mice) and ctrl mice (black; 21 retinal slices from 11 mice) during MCT trans-acceleration with oxamate. Traces were normalized to “zero” lactate (values at the end of the experiment). f Basal lactate levels (individual values and means ± SD) in \(rod^{\varDelta \ Vhl}\) and ctrl PRs calculated from the laconic traces shown in (e). g Schematic representation of lactate transport inhibition by pharmacologically blocking MCT activity with AR-C155858. h Laconic traces (mean ± SD) in PRs of \(rod^{\varDelta \ Vhl}\) (orange; 24 retinal slices from 11 mice) and ctrl mice (black; 23 retinal slices from 8 mice) during MCT block with AR-C155858. Traces were normalized to baseline (values before MCT inhibition). i Intracellular lactate accumulation (amplitude, left) and production rate (slope, right) calculated from the laconic traces shown in (h). Shown are individual values and means ± SD. Statistics: Mann-Whitney nonparametric test. PS: photoreceptor segments. ONL: outer nuclear layer. OPL: outer plexiform layer. INL: inner nuclear layer