Research Projects
Molecular Basis of Neuronal Mitochondria Functions in Normal Ageing and Parkinson’S Disease Using In Vitro and In Vivo Experimental Models

Objective and Significance:

Parkinson's disease (PD) is characterized by loss of nigrostriatal dopaminergic (DA) neurons which control body movement and stability. Mitochondrial dysfunction and neuroinflammation cause reactive oxygen species (ROS) generation, which is a major cause of DA cell death in PD. Mitochondrial Complex-I deficiency and neuroinflammation form a vicious cycle resulting in further damage. Developing strategies to slow down neurodegeneration from inflammatory damages remain a viable approach to delay PD progression. Our studies aim to elucidate the bioenergetic mechanism of how neuronal mitochondrial uncoupling proteins (UCPs) regulate respiratory complexes activity and oxygen consumption to increase ATP synthesis, and prevent ROS generation; and to elucidate how UCP expression maintain oxidative balance and energy supply in survival of primary neuron against inflammatory stresses, and how UCP expression under NF-κB activation in astrocytes affects the release of neurotrophic factors and neuronal survival. Our present work highlights the possibility of improving cellular energy homeostasis by intervention to mitochondrial respiratory complexes to support neuronal survival.

Research Plan and Methodology:

To understand the changes of mitochondria bioenergetics, we will use human neuroblastoma cells either overexpressing or knocking down UCP expression to study the changes in mitochondrial membrane potential (MMP), the overall ATP output, and the levels of ROS generation during normal and stressed conditions. We will measure mitochondrial complexes activity by spectrophotometry enzyme assays, changes in MMP by JC-1 staining, superoxide levels by DHE staining, and ATP production via either Complex-I or -II respiration. Mitochondria will be isolated to measure oxygen consumption and their state of coupling to demonstrate the efficiency of mitochondria (e.g. State4:State3; ADP:O ratios). Also, we will determine cell survival against inflammatory stresses after modulating expression level of UCP in primary neurons and astrocytes. We will assess the level of neuronal cell death (both necrotic and apoptotic) using cell viability assays and flow cytometry, followed by sets of mitochondrial assays as described. For astrocytes, we will compare the release of neurotrophic factors, including BDNF, GDNF, NGF, glutamate, and ATP, after overexpressing or knocking down UCP4 by western blot and ELISA as previously described. Levels of neurotrophic factors will be determined in astrocyte conditioned medium with and without inflammatory stimuli (e.g. TNFα and LPS), to determine the potential effects of astrocyte released factors on neuronal survival.

Professor SL Ho, Department of Medicine

Biography
slho@hku.hk

For more information or to express interest for this project, please email the supervisor or the specified contact point in the project description.  Interested candidates are advised to enclose with your email:

1. your CV,
2. a brief description of your research interest and experience, and
3. two reference letters (not required for HKUMed UG students seeking MRes[Med]/URIS projects).

Information on the research programme, funding support and admission documentations could be referenced online at the Research Postgraduate Admissions website. General admission enquiries should be directed to rpgmed@hku.hk.

HKUMed MBBS students interested in the Master of Research in Medicine (MRes[Med]) programme may visit the programme website for more information.  

HKUMed UG students interested in the Undergraduate Research Internship Scheme (URIS) may visit the scheme’s website for more information.