Related Experiment Videos
The phorbol ester, TPA, increases transepithelial epidermal growth factor flux
FEBS Letters
|September 14, 1987
Summary
Tumor promoter TPA increases kidney cell permeability, significantly raising the flux of mannitol and epidermal growth factor (EGF) across cell layers. This suggests TPA disrupts intercellular junctions, potentially via protein kinase C activation.
Area of Science:
- Cell Biology
- Biochemistry
- Renal Physiology
Background:
- Kidney epithelial cells form tight barriers crucial for function.
- Tumor promoters like TPA can disrupt cellular processes.
- Protein kinase C is a key signaling pathway involved in cell regulation.
Purpose of the Study:
- To investigate the effect of TPA on kidney epithelial cell permeability.
- To determine if TPA alters intercellular junction integrity.
- To explore the role of protein kinase C in TPA-induced permeability changes.
Main Methods:
- Exposure of LLC-PK1 cell sheets to TPA.
- Measurement of transepithelial voltage and D-mannitol flux.
- Dual labeling with D-[14C]mannitol and 125I-EGF.
- Gel filtration and electrophoresis to quantify EGF flux.
Main Results:
- TPA rapidly decreased transepithelial voltage.
- TPA caused a >40-fold increase in D-mannitol flux, indicating leaky junctions.
- TPA treatment increased transepithelial EGF flux by 35-fold.
- Diacylglycerols also increased junctional permeability.
Conclusions:
- TPA disrupts intercellular junctions in kidney epithelial cells.
- The observed effects suggest protein kinase C involvement in TPA-induced permeability.
- TPA significantly enhances the passage of molecules like EGF across the cell barrier.