Abstract
The onset of neurodegenerative diseases activates inflammation that leads to progressive neuronal cell death and impairments in cognition (Alzheimer's disease) and sight (age-related macular degeneration [AMD]). How neuroinflammation can be counteracted is not known. In AMD, amyloid β-peptide (Aβ) accumulates in subretinal drusen. In the 5xFAD retina, we found early functional deficiencies (ERG) without photoreceptor cell (PRC) death and identified early insufficiency in biosynthetic pathways of prohomeostatic/neuroprotective mediators neuroprotectin D1 (NPD1) and elovanoids (ELVs). To mimic an inflammatory milieu in wild-type mouse, we triggered retinal pigment epithelium (RPE) damage/PRC death by subretinally injected oligomeric β-amyloid (OAβ) and observed that ELVs administration counteracted their effects, protecting these cells. In addition, ELVs prevented OAβ-induced changes in gene expression engaged in senescence, inflammation, autophagy, extracellular matrix remodeling, and AMD. Moreover, as OAβ targets the RPE, we used primary human RPE cell cultures and demonstrated that OAβ caused cell damage, while ELVs protected and restored gene expression as in mouse. Our data show OAβ activates senescence as reflected by enhanced expression of p16(INK4a), MMP1, p53, p21, p27, and Il-6, and of senescence-associated phenotype secretome, followed by RPE and PRC demise, and that ELVs 32 and 34 blunt these events and elicit protection. In addition, ELVs counteracted OAβ-induced expression of genes engaged in AMD, autophagy, and extracellular matrix remodeling. Overall, our data uncovered that ELVs downplay OAβ-senescence program induction and inflammatory transcriptional events and protect RPE cells and PRC, and therefore have potential as a possible therapeutic avenue for AMD.