Calreticulin (crt-1) silencing reduces Aß1–42-induced toxicity and restores muscle function in C. elegans.

Abstract

Accumulation of aggregated β-amyloid peptide is a key histopathological feature of Alzheimer's Disease (AD). Experimental models of AD based on β-amyloid peptide display calcium (Ca²⁺) signaling alterations, and targeting key components of the cellular Ca²⁺ signaling system has been postulated to modulate AD onset and progression. Here we have taken advantage of a C. elegans strain that over-expresses the most toxic human ß-amyloid peptide (Aß_1–42) in body-wall muscle cells, to study the impact of calreticulin (crt-1) silencing on body-wall muscle performance. Crt-1 knockdown reduced the percentage of paralyzed worms in a dose-dependent manner and improved locomotion parameters in free-mobility assays in Aß_1–42-overexpressing worms. At the cellular level, crt-1 silencing prevented Aß_1–42-induced exacerbated mitochondrial respiration and mitochondrial ROS production without impacting mitochondrial sarcomere organization. Crt-1 knockdown reduced the number and size of Aß_1–42 aggregates in body-wall muscle cells and prevented the formation of Aß_1–42 oligomers. We propose that crt-1 depletion reduces the number of Aß_1–42 aggregates, precluding Aß_1–42-induced mitochondrial toxicity and improving muscle function. We identify C. elegans crt-1 as a gene involved in the toxicity associated with the expression of human Aß_1–42, and thus a potential new target for treatment.