Abstract
Purpose :
We recently reported that a 4-month period of repetitive hypoxic conditioning (RHC) in F0 adult mice results in functional protection of their adult F1 (first-generation) offspring. This “inherited” resilience to retinal injury in F1 mice likely involves epigenetic modifications of the resting retina, prior to ischemia (a “priming of the pump”), as well as additional reprogramming that is initiated by ischemia itself. To begin to elucidate the mechanism of such intergenerational epigenetic inheritance, we performed mass spectrometry on the resting retinas from these F1 mice, and the resting retinas from matched F1 control mice derived from F0 parents without RHC treatment.
Methods :
At 12 wks of age, F0 Swiss-Webster ND4 mice were exposed to 16 wks of RHC and mated a week later. When their offspring reached 30 wks of age, their retinae were harvested and processed for MS3 analysis on a Fusion Orbitrap Mass Spectrometerusing TMT labels for quantification, A 1.5 FC was used with a <1% FDR. Proteins of interest (POIs) were validated using Western blot analysis and parallel reaction monitoring (PRM). Subsequent bioinformatic analysis was performed on the differentially expressed proteins using Ingenuity Pathway Analysis software.
Results :
MS3 analysis identified a total of 4,176 proteins, of which, 4,041 were quantified. 471 proteins exhibited significant abundance differences, with 363 up and 108 down, in retinae of F1 mice derived from RHC-treated F0 parents relative to retinae of F1 mice from untreated F0 parents. 13C-peptides were used in POI-PRM. Bioinformatic analysis revealed broad changes in fundamental biochemical pathways in the F1 retinae including metabolism, mitochondrial oxidative phosphorylation, G-protein signaling, synaptogenesis, and photoreceptor visual transduction.
Conclusions :
These findings reveal broad changes in the resting proteomic signature of the F1 retina involving critical metabolic and structural shifts that are likely to contribute to the tissue’s resilience to ischemic injuries. This remodeled retinal proteome not only identifies many unique targets for advancing neuroprotective therapeutics for ischemic retinopathies, but also provides key mechanistic insights into how intergenerational epigenetics results in the manifestation of an adaptive phenotype in tissues of the adult progeny secondary to treating only the parents.
This is a 2020 ARVO Annual Meeting abstract.