Neuroscientists at UQ's Queensland Brain Institute (QBI) have revealed two major discoveries, edging them closer to harnessing the brain's inherent powers of self-repair and regeneration.
In findings published in the Journal of Neuroscience, QBI neuroscientists have identified the stem cell population responsible for production of neurons and the mechanism which drives this process.
The research – published in two scientific papers – builds on the pioneering 1992 discovery of the presence of precursors in the adult brain which have the potential to produce neurons, a process also called neurogenesis.
QBI Director Professor Perry Bartlett said the research offered a ‘new insight' into how this regulation might occur.
“For the first time, we've been able to identify a mechanism that's able to regulate production of nerve cells, a step that's crucial to our understanding of memory and learning,” Professor Bartlett said.
“The same mechanism helps regulate growth of healthy brain tissue, so identifying this process is essential for the development of therapeutics to treat conditions such as dementia.”
Neuroscientists at UQ have long been intrigued by the way nerve cells are formed in the hippocampus – a part of the brain crucial to memory – as this function is known to degenerate with age or disease.
“For more than 15 years, we've known that the brain contains stem cells, but until now we have not been able to identify the mechanisms that regulate production of these new nerve cells,” Professor Bartlett said.
He said the latest research was more evidence the human central nervous system had the potential capacity to respond to its outside environment by generating new nerve cells.
Both the QBI studies confirmed that the naturally occurring protein – brain-derived neurotrophic factor (BDNF) – is vital for neurons to develop from precursor-stage cells.
In one of the QBI studies, a series of experiments demonstrated that the chemical receptor (p75) plays an important role in enhancing nerve cell production.
In the other study, a team of QBI neuroscientists found a way to identify neurons at the intermediate stage of development, when the cells are in the process of changing from stem cells to mature nerve cells.
The discovery charts how this complex natural process occurs in a healthy brain, using the protein Doublecortin (DCX) as a marker.
Using the DCX marker to identify intermediate cells advances understanding of the hippocampus and provides researchers with a powerful new way of visualising a mechanism which had until recently been essentially theoretical.
QBI's Dr Tara Walker said the DCX findings meant scientists could now isolate and study specific cells of interest in the hippocampus, a region which has a high turnover of neural stem cells.
“Our immediate goal was to identify the genes important in promoting the survival and differentiation of these immature nerve cells,” she said.
“With this knowledge, we are well placed to further develop our understanding of the basic mechanisms that regulate the generation of healthy, new nerve cells in the brain.”
“Our long-term goal is to develop new therapies whereby nerve cells can be generated to replace those lost or damaged in disease or trauma,” she said.
The QBI research augments on-going efforts to identify mechanisms that can repair compromised brain tissue and represents another milestone in understanding the fundamental workings of the brain.
Significant advances in determining the molecular regulation of nerve cell function and development will have a major impact on our understanding of more complex areas such as behaviour, cognition, ageing, neurological disease and mental illness.
Mental and neurological diseases account for about 45 per cent of the burden of disease in Australia.
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Notes to the Editor
QUEENSLAND BRAIN INSTITUTE
The Queensland Brain Institute was formed in 2003 as part of the Queensland Government’s Smart State Initiative, building on a long history of neuroscience at The University of Queensland. QBI is dedicated to understanding the molecular basis of brain function and applying this knowledge to the development of new therapeutics to treat brain and mental health disorders.
RELEVANT RESEARCH PAPERS
p75 Neurotrophin Receptor Expression Defines a Population of BDNF-Responsive Neurogenic Precursor Cells – Journal of Neuroscience, 9 May 2007
The Doublecortin-Expressing Population in the Developing and Adult Brain Contains Multipotential Precursors in Addition to Neuronal-Lineage Cells – Journal of Neuroscience, 4 April 2007