Studies on localization and function of annexin A4a within urinary bladder epithelium using a mouse knockout model
Warren G Hill1, Susan Meyers, Maximilian von Bodungen
1Division of Matrix Biology, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA.
American Journal of Physiology. Renal Physiology
|February 8, 2008
Summary
Annexin A4 (anxA4) protein is present in mouse bladders but its absence does not impact bladder barrier function, membrane trafficking, or voiding behavior in knockout mice.
Area of Science:
- Urology
- Cell Biology
- Membrane Biology
Background:
- Annexin A4 (anxA4) is a calcium-dependent protein involved in membrane regulation.
- Annexins 1-6 are expressed in the bladder urothelium, with differential localization of anxA4a.
Purpose of the Study:
- To investigate the role of annexin A4a (anxA4a) in mouse bladder barrier function and membrane trafficking.
- To assess the impact of anxA4a deficiency on bladder physiology and morphology.
Main Methods:
- Generated and utilized an anxA4a-knockout mouse model.
- Performed immunofluorescence, immunoblotting, Ussing chamber experiments, capacitance measurements, cystometrograms, and electron microscopy.
Main Results:
- Annexin A4a knockout bladders showed no alterations in transepithelial resistance, water, or urea permeability.
- Hydrostatic pressure-induced membrane trafficking and bladder voiding parameters were normal in knockout mice.
- No significant differences in bladder surface morphology or cellular architecture were observed.
Conclusions:
- Loss of urothelial annexin A4a does not compromise bladder barrier integrity.
- Annexin A4a is not essential for stretch-activated membrane trafficking or normal bladder function.
- The study clarifies the non-essential role of anxA4a in maintaining bladder homeostasis.
