Beta-Amyloid is a Substrate of Autophagy in Sporadic Inclusion Body Mysositis

Sporadic Inclusion Body Myositis (sIBM) is the most common acquired muscle disease in patients above 50 years of age. Apart from inflammation in the skeletal muscle, overexpression of amyloid precursor protein (APP) and intracellular accumulation of its proteolytic fragment beta-amyloid play a central role in the pathogenesis of sIBM. We demonstrate here that the essential autophagy protein Atg8/LC3, which associates with preautophagosomal and autophagosomal membranes via lipidation, colocalizes with APP in cultured human muscle cells. In addition, APP/beta-amyloid-containing autophagosomes can be observed at in…