Cellular Mechanisms Underlying the Nervous System

The long term goal of my research is to decipher the cellular structure and functions in neurons. From my academic training and research experience, I have acquired a diverse set of research expertise in biochemistry, molecular biology, neurophysiology, neuroanatomy and behavioral neuroscience.

During my undergraduate and graduate careers, I received a number of academic and clinical awards.

As a predoctoral student, my research focused on collagen in diabetic wounds from the perspectives of biomechanical assessment and electromagnetic treatment, in which I gained expertise in biomechanical, biochemical and histological characterization of tissues from rodents.

During my predoctoral training, I also conducted research related to the nervous system. First, I found that electromagnetic intervention can increase VEGF expression of hippocampus challenged by diabetic condition in rats. The electromagnetic intervention appears to be also able to partly rescue the memory deficit under diabetic condition. This result led to a platform presentation in a renowned international conference.

Second, I found that Lycium bararum polysaccharides, a fruit extract, rescues apoptosis around vasculature in the hippocampus of diabetic rats, associated with a trend of better performance in memory test. The result led to a poster presentation in an international conference.

Third, in collaboration with Dr. Stuart Peirson and Prof. Russell Foster who are prestige chronobiologists and neuroscientists, we found that both hippocampus and olfactory bulbs have their own intrinsic circadian rhythm which is coordinated by the suprachiasmatic nucleus. Constant light can dampen the circadian rhythm of the suprachiasmatic nucleus and disrupt the coordination of circadian rhythm between hippocampus and olfactory bulbs. The hippocampus and olfactory bulbs then retain their own intrinsic circadian rhythm. This study establishes important and novel findings and implications in the previously unexplored field of chronobiology and neuroscience. The result was published in Journal of Neuroscience.

From the above work, I am fascinated by the functional changes of the nervous system brought by neuroplasticity. Therefore, for my postdoctoral training, I continue to utilize my expertise in biochemistry, molecular biology and behavioral neuroscience to study the nervous system in greater details. As synapse is the primary functional unit of neurons, which is the basic unit of the nervous system, I worked with Dr. Geoff Lau to investigate the synaptic plasticity under physiological and pathological conditions using the anterior piriform cortex as a model system, through which I have also acquired extra skills in electrophysiology and neuroanatomy. In this project, I characterized the excitatory/inhibitory synaptic plasticity in the anterior piriform cortex under sensory deprived and epileptic conditions. The findings were presented in a local conference.

Now, I am working with Dr. Marta Lipinski as a postdoc fellow to investigate autophagy secondary to spinal cord injury, which has potential implications in the dysfunctions of neurites. I have contributed to characterize autophagy markers and the role of mTOR pathway in autophagy and necroptosis after spinal cord injury. The result led to a poster presentation in a renowned international conference and a submitted manuscript. Recently, I started to focus on autophagy in injured axons.

With my expertise in biochemistry, molecular biology, neurophysiology, neuroanatomy and behavioral neuroscience, as well as extensive experience in the nervous system, I am confident to the success of my research goals.

1. Li Y, Jones JW, Choi HMC, Sarkar C, Kane MA, Koh EY, Lipinski MM, Wu J. cPLA2 activation contributes to lysosomal defects leading to impairment of autophagy after spinal cord injury. Cell Death and Disease. 2019; 10: 531.

2. Liu S, Li Y, Choi HMC, Sarkar C, Koh EY, Wu J, Lipinski MM. Lysosomal damage after spinal cord injury causes accumulation of RIPK1 and RIPK3 proteins and potentiation of necroptosis. Cell Death and Disease. 2018; 9: 476.

3. Choi HMC, Chiu A, Sze CCY, Lau GCY. Plasticity mechanisms of cortical GABAergic circuits in health and disease. Biomedical Sciences Departmental Research Gala; 2017 June; City University of Hong Kong, Hong Kong.

4. Tam SKE, Hasan S, Choi HMC, Brown LA, Jagannath A, Hughes S, Hankins MW, Foster RG, Vyazovskiy VV, Bannerman DM, Peirson SN. Constant light desynchronises olfactory versus object and visuospatial recognition memory performance. Journal of Neuroscience. 2017; 37(13): 3555-3567.

5. Choi MC, Cheung KK, Zhang Y, Cheing GLY. Can pulsed electromagnetic field (PEMF) be a potential treatment for promoting angiogenesis in diabetic brain? Physiotherapy. 2015; 101: e247.

6. Zhang Y, Choi MC, Cheung KK, So KF, Cheing GLY. Oral administration of Lycium barbarum polysaccharides (LBP) reduce apoptosis in blood vessels of diabetic rat brains. 3rd World Congress on Interventional Therapies for Type 2 Diabetes; 2015 September;​​​ London, UK.