Inhibition of 37/67kDa Laminin-1 Receptor Restores APP Maturation and Reduces Amyloid-β in Human Skin Fibroblasts from Familial Alzheimer's Disease

Alzheimer's disease (AD) is a fatal neurodegenerative disorder caused by protein misfolding and aggregation, affecting brain function and causing dementia. Amyloid beta (A beta), a peptide deriving from amyloid precursor protein (APP) cleavage by-and gamma-secretases, is considered a pathological hallmark of AD. Our previous study, together with several lines of evidence, identified a strict link between APP, A beta and 37/67kDa laminin receptor (LR), finding the possibility to regulate intracellular APP localization and maturation through modulation of the receptor. Here, we report that in fibroblasts from familial AD (fAD), APP was prevalently expressed as an immature isoform and accumulated preferentially in the transferrin-positive recycling compartment rather than in the Golgi apparatus. Moreover, besides the altered mitochondrial network exhibited by fAD patient cells, the levels of pAkt and pGSK3 were reduced in respect to healthy control fibroblasts and were accompanied by an increased amount of secreted A beta in conditioned medium from cell cultures. Interestingly, these features were reversed by inhibition of 37/67kDa LR by NSC47924 a small molecule that was able to rescue the typical APP localization in the Golgi apparatus, with consequences on the A beta level and mitochondrial network. Altogether, these findings suggest that 37/67kDa LR modulation may represent a useful tool to control APP trafficking and A beta levels with implications in Alzheimer's disease.