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Effects of micrometric titanium particles on osteoblast attachment and cytoskeleton architecture

Paper ID Volume ID Publish Year Pages File Format Full-Text
2546 114 2010 12 PDF Available
Title
Effects of micrometric titanium particles on osteoblast attachment and cytoskeleton architecture
Abstract

Titanium (Ti) and its alloys are widely used in biomedical devices as bone tissue replacements due to their advantageous bulk mechanical properties and biocompatibility. It is known that particles released from Ti-based implants impair essential functions of osteoblasts, which for survival require attachment to specific extracellular matrix proteins at the bone surface. This study investigates whether Ti particles of micrometric sizes affect the osteoblast attachment machinery. Exposure of human osteoblastic Saos-2 cells to Ti particles impaired their adhesion strength, migration and proliferation. Attenuation of these functions was associated with reduced cell spreading, cell membrane disruptions and loss of cell shape. Cell exposure to Ti particles led to changes in cytoskeletal structures, including reduced ventral stress fibers combined with a disorderly arrangement of β-tubulin and acetylated α-tubulin fibers. Cytoskeleton disassembly was associated with a reduction in overall cell adhesion area, characterized by fewer centrally localized focal adhesions and shorter focal contacts at the periphery. Paxillin adaptor protein redistributed to peripheral corner regions, colocalizing with poorly organized actin fibers at attachment sites. Total focal adhesion kinase (FAK) protein amounts, as well as its degree of phosphorylation on the active form p-FAK (Tyr-397), decreased, which was accompanied by a lesser extent of co-localization with paxillin in focal contacts. On the other hand, p-FAK (Tyr-407), an inhibitory form of FAK, accumulated in the focal contacts of Ti-treated cells. Pyk2 phosphorylated on Tyr-402 colocalized with paxillin in focal contacts of untreated cells, while it was barely detected upon exposure to particles. In summary, changes in the phosphorylation states of both FAK and Pyk2 tyrosine kinases at focal contacts underlie impaired bone-forming cell attachment after exposure to Ti particles of micrometric sizes.

Keywords
Titanium; Microparticles; Osteoblasts; Cell adhesion; Confocal microscopy
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Effects of micrometric titanium particles on osteoblast attachment and cytoskeleton architecture
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Publisher
Database: Elsevier - ScienceDirect
Journal: Acta Biomaterialia - Volume 6, Issue 4, April 2010, Pages 1649–1660
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us