Lecture 23 - Mechanobiology I Flashcards
What is mechanobiology?
The study oof how physical forces and changes in cell or tissue mechanics contribute to development, physiology and disease
What is Mechanotransduction?
Conversion of physical forces into a biochemical response
What is Mechanosensing?
When a protein or cellular structure responds to a physical cue to initiate mechanotransduction
What are the separate steps in Mechanotransduction?
1.Mechanosensing - cells test environment (adhesion receptors, membrane proteins probe ECM)
2. Signal transduction - mechanical signal transduced along a linked network. Cytoskeleton is the force conduit
3. Signal integration at the nucleus - accumulation of signals over time. Chromatin rearrangement, nuclear pore opening
4. Cellular response - from microseconds to minutes. Cell shape, fate, motility and growth
(can skip signal integration at nucleus step sometimes)
How is mechanotransduction used in BP autoregulation?
Increased BP means blood flow is faster, body keeps blood flow constant so needs to counteract this.
After 3rd threshold is exceeded diameter of artery decreases in order to limit blood flow.
What causes strain in fluid flow?
Cells change their cytoskeleton upon fluid flow
Mechanical cue in the blood system is fluid flow which causes the force STRAIN.
Cell recognises the mechanical cue of fluid flow.
What causes strain in fluid flow?
Cells change their cytoskeleton upon fluid flow
Mechanical cue in the blood system is fluid flow which causes the force STRAIN.
Cell recognises the mechanical cue of fluid flow.
What sort of Mechnotransduction is present in the ear?
Stereocilia - deflect when sound reaches ear. Movement of gel in ear. Movement exerts force on cilia, they bend and this bending opens ion channel
What does a lung-on-chip do?
It reconstitutes organ-level lung functions on a chip. Emulates lung activity.
Used to study lung inflammation
Alveoli is a tissues constantly contracting and expanding where gas exchange occurs. But it’s an important interface to the environment.
How does a lung chip actually emulate the lungs?
- To recognise alveoli, 2 cell types, epithelial cells and endothelial cells.
- Sysytem emulates these 2 cells being close. Achieved through membrane with small pores and is stretchy.
- 2 side chambers allow us to add and release a vacuum, shows a change in membrane (starts to stretch)
What forms when cell layers are stretched?
Forms proper tight junctions
What does the uptake of nanoparticles require?
Mechanical strecthing
