Award details

Synthesis and biological testing of cell-permeant NAADP

Reference	BB/D012694/1
Principal Investigator / Supervisor	Dr Grant Churchill
Co-Investigators / Co-Supervisors
Institution	University of Oxford
Department	Pharmacology
Funding type	Research
Value (£)	213,016
Status	Completed
Type	Research Grant
Start date	01/05/2006
End date	30/04/2009
Duration	36 months

Abstract

Inside cells calcium functions as a messenger and drives many processes such as fertilization, muscle contraction, secretion and even regulated cell death. The molecule NAADP (nicotinic acid adenine dinucleotide phosphate) releases calcium from intracellular stores and may also stimulate influx. Although NAADP is known to releases calcium in several cell types, including many mammalian cells, the precise physiological role of NAADP is ill defined in all but the pancreatic acinar cells. A large impediment to research in this area is that NAADP has three phosphates and a carboxylic acid group and thus possesses a net negative charge. Being relatively large and highly charged it is does not cross membranes and has to be introduced by microinjection or other techniques that breech the plasma membrane. Cell permeant versions of NAADP would greatly facilitate research into NAADP in all mammalian cell types in which it has been implicated to have a role (based on calcium release). Moreover, cell-permeant caged NAADP would enable many elegant experiments that would reveal much about the physiology of NAADP. To this end, we are particularly excited about a role for NAADP in serotonin (5-hydroxytryptamine) signalling in the brain. We propose to make cell-permeant and caged versions of NAADP, fully characterize them in terms of uptake and metabolism, and then use them to further define the role of NAADP in serotonin signalling.

Summary

Cells communicate with other cells and internally via chemical messengers. These messenger are molecules and exhibit features that make them uniquely recognizable to specialised receptors, or biological message centres. Messengers are made inside the cell membrane in response to outside stimuli, but cannot cross to or from the outside. This is because cells are enveloped by a membrane which keeps the contents in and potential contaminants outside. We are interested in a messenger molecule that increases calcium levels inside cells, called NAADP. Changes in calcium levels is what drives your heart to contract, your arm muscle to contract to raise a cup to your mouth and even the cells in your brain to talk to each other. Nobody is yet sure NAADP is working, so we want to get it into cells and find out. This messenger molecule does not naturally cross the cell membrane, so current state of the art techniques involve destroying the membrane then rebuilding it. This is difficult and requires specialised skills. We propose to try a different, more subtle approach by masking the molecules appearance, so that it can slip through the membrane. Once inside, the molecule sheds its mask, regains its appearance and provides its message. Getting NAADP across the cell membrane by stealth will provide us with new information about how this messenger works in different cells. Successful development of this new method will allow many more scientists to study this fascinating molecule.

Committee	Closed Committee - Biochemistry & Cell Biology (BCB)
Research Topics	Neuroscience and Behaviour
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

Associated awards:

BB/D010810/1 Synthesis and biological testing of cell-permeant NAADP

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