Quick Project Snapshot
Bioengineered 3D astrocytes to reveal healthy biology and neurotherapeutic targets
Are Astrocytes are the most important cells in the mammalian brain? They are not just “housekeeping” cells:
- Outnumber neurons (60% of total cells)
- Maintain the integrity of blood-brain-barrier
- Support tight junction formation
- Provide energy substrates to neurons
- Remove toxic L-glutamate
- Release L-glutamine for neuronal synthesis of L-glutamate
- Release gliotransmitters
- Synthesise and release BDNF/GDNF
- Site of major anti-oxidant activity in brain
And this is healthy brain! They are even more important in pathologies? A revolution is underway in our understanding of astrogliosis – researchers now believe astrocytes can be recruited to display a “good” (i.e. healthy) rather than “bad” phenotype in the inflammatory milieu of reactive gliosis. Using a unique experimental model (3D astrocytes) we have defined this healthy phenotype as possessing elevated L-glutamate (Glu) transport, BDNF and anti-oxidant activities, and stellated morphology reminiscent of in vivo. We are the FIRST GROUP INTERNATIONALLY to achieve long-term culture of mature astrocytes in 3D (Journal of Neurochemistry (2014) 130: 215-26), giving us a unique opportunity to advance astrocyte biology! We contend the failure to manage inflammation in neuropathologies has been a shortcoming in our understanding of molecular signatures governing astrocyte health. Thus whilst we have the “signposts” of a healthy astrocyte, we shall use our 3D astrocytes to fully elucidate the mechanisms governing promotion of this healthy phenotype and to identify neurotherapeutic targets beneficial in diverse pathologies.
Aim: To elucidate the mechanisms altering astrocytic morphology and biology, and hence determining astrocytic health.
Techniques involved: Primary culture; Use of bioengineered scaffolds; Immunocytochemistry; Confocal microscopy; Western blotting; Proteomics; Bioinformatics
- 3D Electrospun scaffolds promote a cytotrophic phenotype of cultured primary astrocytes. Lau CL, Kovacevic M, Tingleff TS, Forsythe JS, Cate HS, Merlo D, Cederfur C, Maclean FL, Parish CL, Horne MK, Nisbet DR, Beart PM. J Neurochem. 130: 215-26 (2014).
- Transcriptomic profiling of astrocytes treated with the Rho kinase inhibitor fasudil reveals cytoskeletal and pro-survival responses. Lau CL, Perreau VM, Chen MJ, Cate HS, Merlo D, Cheung NS, O'Shea RD, Beart PM. J Cell Physiol. 227: 1199-211 (2012).
- The Rho kinase inhibitor Fasudil up-regulates astrocytic glutamate transport subsequent to actin remodelling in murine cultured astrocytes. Lau CL, O'Shea RD, Broberg BV, Bischof L, Beart PM. Br J Pharmacol. 163: 533-45 (2011).
Cellular Neurodegeneration Laboratory
Pathological mechanisms affecting neurons and astrocytes, which have an interdependent relationship essential to brain health, are the focus of our laboratory. Diverse experimental approaches provide insights into how new strategies may be targeted to rescue threatened neurones and to establish a supportive environment near an injury zone.
Ageing or injured neurones accumulate damaged molecules and organelles which affect their function. This process is termed autophagy (“self-eating”) and represents one of the cellular rubbish removal mechanisms. If the load becomes too extreme or if the autophagic mechanisms become compromised, the process can become a form of programmed cell death. Most research into the controlling mechanisms has been performed in non-mammalian cells, so our work in primary neurones is groundbreaking. Damaged mitochondria also enter the autophagic cascade through a process termed mitophagy. We have found that disturbed energy generation causes mitochondria to lose their membrane potential with a concomitant drop in ATP production and entry into mitophagy. Since disturbed energetics underpins various forms of neurodegeneration, we believe that this cascade contributes to many degenerative conditions. We are currently investigating autophagy in other brain injury models.
Over many years our team has studied the neurobiology of astrocytes and made impressive advances in defining “good” or “bad” responses which relate to the state of inflammation in brain patholgies. By culturing mature astrocyes in 3D on bioscaffolds, we found a healthy astrocytic phenotype displaying reduced GFAP, and increased G-actin, glutamate transport, brain-derived trophic factor (BDNF) and anti-oxidant activity. These “signposts” guide current studies where a novel bioscaffold presenting sugar moieties has shown promise in minimising inflammation in studies performed in cultured astrocytes and in vivo in model of traumatic brain injury. The ultimate goal is a safe, bio-injectable to prevent untoward glial scarring and to promote regeneration.
All Projects by this LabBioengineered 3D astrocytes to reveal healthy biology and neurotherapeutic targets
Dr Lachlan Thompson
Prof David Finkelstein
Scientists in the Neurodegeneration division interrogate how neurones live, die and can be rescued to improve brain function in degenerative conditions such as Parkinson’s and Motor Neuron Diseases. There is no effective treatment for Motor Neurone Disease and the incidence of Parkinson’s Disease is rising alarmingly in our aging community. Gene abnormalities, energy deprivation, toxic rubbish accumulation and inflammation all contribute to a toxic environment for brain cells. Our teams study these events in animal models and cultured cells, with a view to translating knowledge into new therapies for human patients.