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Bradykinin activates ADP-ribosyl cyclase in neuroblastoma cells: intracellular concentration decrease in NAD and
Haruhiro Higashida1, Alla Salmina, Minako Hashii
1Department of Biophysical Genetics, Kanazawa University Graduate School of Medicine, 13-1 Takara, Kanazawa, Ishikawa 920-8640, Japan. haruhiro@med.kanazawa-u.ac.jp
FEBS Letters
|August 15, 2006
Summary
Bradykinin (BK) stimulates ADP-ribosyl cyclase activity in NGPM1-27 cells, increasing cyclic ADP-ribose (cADPR) levels. This suggests cADPR acts as a second messenger for B(2) BK receptors.
Area of Science:
- Biochemistry
- Cell Signaling
- Neuroscience
Background:
- Neuroblastoma x glioma hybrid cells (NGPM1-27) possess ADP-ribosyl cyclase activity.
- Nicotinamide adenine dinucleotide (NAD+) is a substrate for ADP-ribosyl cyclase.
- Cyclic ADP-ribose (cADPR) is a known intracellular calcium-mobilizing second messenger.
Purpose of the Study:
- To investigate the effect of bradykinin (BK) on ADP-ribosyl cyclase activity in NGPM1-27 cells.
- To determine if cADPR is involved in the signaling pathway of B(2) BK receptors.
Main Methods:
- Measurement of [(3)H] cADPR formation from [(3)H] NAD(+) in crude membrane fractions.
- Stimulation of living NGPM1-27 cells with BK.
- Quantification of intracellular NAD(+) and cADPR levels using radiolabeling techniques.
Main Results:
- 100nM BK treatment resulted in a 2.5-fold increase in ADP-ribosyl cyclase activity.
- Application of 300nM BK to living cells decreased NAD(+) levels to 78% within 30 seconds.
- Intracellular cADPR concentrations increased 2-3 fold between 30 and 120 seconds post-BK stimulation.
Conclusions:
- Bradykinin significantly enhances ADP-ribosyl cyclase activity in NGPM1-27 cells.
- BK stimulation leads to a decrease in NAD(+) and a subsequent increase in intracellular cADPR.
- These findings support the role of cADPR as a second messenger downstream of B(2) BK receptors.