Project Outline

The brain is very reliant upon a constant supply of oxygen and glucose for the mitochondrial synthesis of ATP to meet the high metabolic demands of neuronal activity. During instances when this supply is interrupted or when the ATP demands of neuronal activity outstrip the synthesis of ATP, the brain utilises a biochemical pathway that salvages ATP metabolites for resynthesis into ATP. Importantly, the metabolism of ATP yields a molecule (adenosine) that acts to reduce neuronal energy demands, while the resynthesis of ATP via the salvage pathway can be enhanced by providing brain tissue with the two primary components of adenosine, ribose and adenine.

In this project we will use imaging approaches based upon mass spectrometry to follow ATP and its metabolites through the salvage pathway. This imaging approach involves using a laser to ionise molecules in brain tissue sections. These molecules are then analysed via the mass spectrometer to build up, pixel by pixel, an image of the location of molecules, in highly defined regions (~10 µm diameter spots), across entire brain sections. With this approach we can ask how the metabolic profile of the brain is affected changes in the supply of oxygen and glucose and intense neuronal activity, how the metabolic profile of the brain changes with ageing and age-related brain conditions, and whether supplementation with ribose and adenine, two compounds used in humans, can improve brain energy metabolism.

The project will involve training in imaging mass spectrometry and in vitro and in vivo approaches for the preparation of brain tissue samples.

References

Gessner P, Lum J, Frenguelli BG. The mammalian purine salvage pathway as an exploitable route for cerebral bioenergetic support after brain injury. Neuropharmacology. 2023 224:109370. https://doi.org/10.1016/j.neuropharm.2022.109370

Frenguelli BG. (2019) The Purine Salvage Pathway and the Restoration of Cerebral ATP: Implications for Brain Slice Physiology and Brain Injury. Neurochem Res. 44:661-675. https://link.springer.com/article/10.1007/s11064-017-2386-6

Techniques

• Mass spectrometry
• Matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI)
• In vitro tissue preparation
• In vivo models of cerebral blood flow reduction
• Electrophysiology
• Cerebral blood flow imaging