Autophagy dysregulation in human fibroblasts from Niemann‐Pick type C patients

• Published in: Alzheimer's & dementia Vol. 19; no. S13
• Main Authors: Pradel‐Bernal, Tamara Patricia, Alcala‐Flores, Rebeca‐Leticia, Gomez‐Virgilio, Laura, Silva‐Lucero, Maria‐del‐Carmen, Rivera‐Osorio, Jared, Cardenas‐Aguayo, Maria‐del‐Carmen
• Format: Journal Article
• Language: English
• Published: 01.12.2023
• ISSN: 1552-5260; 1552-5279
• DOI: 10.1002/alz.079446

Background Niemann‐Pick disease type C (NPC) results from a mutation in the gene that encodes endolysosomal cholesterol‐transport proteins NPC1. NPC is characterized by the accumulation of unesterified cholesterol and other lipids within the cell causing the impaired function of lysosomes and the autophagy flux. The symptoms of the disease are variable and may include: enlarged liver or/and spleen, learning difficulties, seizures, gait problems, dementia, and loss of muscle tone, among others. Macroautophagy is the main recycling pathway of organelles and cellular components in mammalian cells to obtain primary elements in stress conditions such as the absence of nutrients and maintaining cellular homeostasis. During disease, it also helps to get rid of toxic misfolding protein aggregates. Many neurodegenerative diseases are characterized by autophagy impairment. Method In this study, we worked with 3 skin fibroblast cells lines from apparently healthy subjects and 3 from Niemann‐Pick’s patients to corroborate altered autophagy flux made an autophagy induction by chloroquine (10 uM) and serum starvation, first we performed the Cyto‐ID autophagy (Enzo) detection kit and then we analyzed by Western blotting the expression of proteins that are involved in the autophagy pathway to find the altered mechanisms. Result Chloroquine treatment induced a significant decrease in the viability of NPC cells as compared to controls, which correlates with an increase in cytoplasmic autophagy vacuoles (Avs) and an increase in LC3‐II. Also, there was an increased trend in LC3‐II, ATG5, ATG16‐L1 in NPC cells cultured in the presence and absence of nutrients. No significant changes were observed in the expression of p62 between NPCs and control cells. Conclusion NPCs are more sensitive to autophagy induction by Chloroquine than control cells, as demonstrated by morphology (increase in AVs) and LC3‐II, ATG5 and ATG16L1 expression, detected by Western blotting.