Related Experiment Videos
Neprilysin activity and expression are controlled by nicastrin
R Pardossi-Piquard1, J Dunys, G Yu
1Institut de Pharmacologie Moléculaire et Cellulaire du Centre National de la Recherche Scientifique, Equipe labellisée Fondation pour la Recherche Médicale, Valbonne, France.
Journal of Neurochemistry
|April 12, 2006
Summary
Nicastrin (NCT), a gamma-secretase component, is crucial for neprilysin expression and activity, an enzyme that degrades amyloid beta (Abeta) in Alzheimer's disease. Its absence impairs neprilysin, highlighting the need for the complete gamma-secretase complex for proper Abeta clearance regulation.
Area of Science:
- Neuroscience
- Molecular Biology
- Biochemistry
Background:
- The presenilin-dependent gamma-secretase complex regulates neprilysin, a key enzyme for amyloid beta-peptide (Abeta) degradation.
- Alzheimer's disease is characterized by the accumulation of Abeta.
- Nicastrin (NCT) is a crucial component of the gamma-secretase complex.
Purpose of the Study:
- To investigate the role of endogenous nicastrin (NCT) in neprilysin physiology.
- To determine if NCT influences the expression and activity of neprilysin and other Abeta-degrading enzymes.
- To elucidate the mechanism by which the gamma-secretase complex modulates neprilysin.
Main Methods:
- Studied the effects of nicastrin deficiency on neprilysin expression, activity, and mRNA levels in fibroblasts.
- Assessed the impact of nicastrin on other Abeta-cleaving enzymes: endothelin-converting enzyme and insulin-degrading enzyme.
- Utilized NCT cDNA transfection in wild-type and NCT-deficient fibroblasts to observe rescue effects and temporal dynamics.
Main Results:
- Nicastrin deficiency significantly reduced neprilysin expression, membrane-bound activity, and mRNA levels.
- Nicastrin deficiency did not affect the expression of endothelin-converting enzyme or insulin-degrading enzyme.
- Nicastrin restored neprilysin activity and expression in nicastrin-deficient cells, but not in presenilin-deficient cells, indicating the necessity of the complete gamma-secretase complex.
- NCT expression peaked at 24 hours post-transfection, while neprilysin expression increased significantly after 36 hours, suggesting a delayed, indirect transcriptional regulation.
Conclusions:
- Endogenous nicastrin is essential for maintaining neprilysin expression and activity.
- The complete gamma-secretase complex, including nicastrin, is required for the proper regulation of neprilysin.
- The gamma-secretase complex indirectly modulates neprilysin expression at the transcriptional level with a delayed effect.