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

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 (Aß1-42) 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 Aß1-42-overexpressing worms. At the cellular level, crt-1 silencing prevented Aß1-42-induced exacerbated mitochondrial respiration and mitochondrial ROS production without impacting mitochondrial sarcomere organization. Crt-1 knockdown reduced the number and size of Aß1-42 aggregates in body-wall muscle cells and prevented the formation of Aß1-42 oligomers. We propose that crt-1 depletion reduces the number of Aß1-42 aggregates, precluding Aß1-42-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 Aß1-42, and thus a potential new target for treatment.