| Autor: |
Kruger TM; Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy , The University of Iowa , Iowa City , Iowa 52242 , United States., Bell KJ; Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy , The University of Iowa , Iowa City , Iowa 52242 , United States., Lansakara TI; Department of Chemistry , The University of Iowa , Iowa City , Iowa 52242 , United States., Tivanski AV; Department of Chemistry , The University of Iowa , Iowa City , Iowa 52242 , United States., Doorn JA; Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy , The University of Iowa , Iowa City , Iowa 52242 , United States., Stevens LL; Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy , The University of Iowa , Iowa City , Iowa 52242 , United States. |
| Abstrakt: |
Alzheimer's disease (AD), the most common neurodegenerative disorder, is characterized by the extracellular deposition of dense amyloid beta plaques. Emerging evidence suggests that the production of these plaques is initiated by the intracellular uptake and lysosomal preconcentration of the amyloid-beta (Aβ) peptide. All previous endocytosis studies assess Aβ uptake with cells plated on traditional tissue culture plastic; however, brain tissue is distinctly soft with a low-kPa stiffness. Use of an ultrastiff plastic/glass substrate prompts a mechanosensitive response (increased cell spreading, cell stiffness, and membrane tension) that potentially distorts a cell's endocytic behavior from that observed in vivo or in a more physiologically relevant mechanical environment. Our studies demonstrate substrate stiffness significantly modifies the behavior of undifferentiated SH-SY5Y neuroblastoma, where cells plated on soft (∼1 kPa) substrates display a rounded morphology, decreased actin polymerization, reduced adhesion (decreased β 1 integrin expression), and reduced cell stiffness compared to cells plated on tissue culture plastic. Moreover, these neuroblastoma on softer substrates display a preferential increase in the uptake of the Aβ(1-42) compared to Aβ(1-40), while both isoforms display a clear stiffness-dependent increase of uptake relative to cells plated on plastic. Considering the brain is a soft tissue that continues to soften with age, this mechanosensitive endocytosis of Aβ has significant implications for understanding age-related neurodegeneration and the mechanism behind Aβ uptake and fibril production. Overall, identifying these physical factors that contribute to the pathology of AD may offer novel avenues of therapeutic intervention. |
