(a) You would like to test the adhesion of osteoblasts on different extracellula
ID: 163834 • Letter: #
Question
(a) You would like to test the adhesion of osteoblasts on different extracellular matrix (ECM) proteins. You first spot the ECM proteins directly on glass slides. Then, the osteoblasts are cultured in media containing serum for 2 days on the slides. When you examine the slides, you find that the cells have attached to the entire glass slide (not just your spotted ECM proteins). Explain this result.
(b) A coworker gives you another slide with the ECM proteins already spotted. They mention that they first coated the glass slide with Polymer A-silane. What is a surface modification technique that may have been used to alter the slide with the
Polymer A-silane?
(c) When you culture the osteoblasts under the same conditions, you find that after 2 days the cells now only adhere to the regions of the spotted ECM proteins. Explain why Polymer A prevented the cells from adhering to the glass.
(d) How are the cells interacting with the protein-spotted materials?
(e) Due to favorable cell-material interactions with spots, what could then occur tothe osteoblasts (e.g., what cell function(s) are affected) (there are many answers – only one potential outcome is necessary)? How does the extracellular interaction get ranslocated intracellularly to affect cell function?
Explanation / Answer
Answer (a):
Anchorage (Adhesion) of Osteoblast cells rely not only on physical substrates, such as glass or plastic, for attachment and differentiation, but also on proteins. Cell spreading, proliferation, and repair pathways are influenced by biochemical adhesion factors on the surface. These biochemical signals may result from the presence of peptides, proteins, carbohydrates, and other molecules soluble in the cellular environment.
An early adhesion signifies that most of the cells are concentrated into the graft with a strong attachment and therefore cells will start sooner to spread.
Fibronectin is an extracellular matrix protein and Fibronectin enhancing effect on cell adhesion has been proved in several cell types. Initial approaches of coating dishes and analyzing cell adhesion have proved that fibronectin enhances rapid cell adhesion and spreading of mesenchymal stem cells (multipotent stromal cells that can differentiate into a variety of cell types, including: osteoblasts).
Also, it has been demonstrated that collagen type I (another extracellular matrix protein) speeds up initial adhesion of osteoblasts compared with fetal calf serum after 1 h cells flat and spread.
It is because of this phenomenon that the osteoblast cells have spread and attached to the entire glass slide (and not just the spotted ECM proteins).
Thank you!
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