Parkinson’s disease is a neurodegenerative disorder which is difficult to detect in preclinical state. Often times, patients are diagnosed in advanced stages where they already are observed with signs of Parkinson’s disease.
Researchers in the National University of Singapore co-led by Professor Yao Shao Qin from the Department of Chemistry, Faculty of Science and Associate Professor Lim Kah Leong, from the National Neuroscience Institute and also the Department of Physiology at NUS Yong Loo Lin School of Medicine, have created a solution to this problem. Their team was able to develop the world’s first small, two-photon fluorogenic molecular probe which may help in the assessment of the potential risk an individual may have to develop Parkinson’s disease and also detect the disease in persons who are yet to develop Parkinson’s disease symptoms.
The human brain contains Monoamine Oxidase A (MAO-A) and Monoamine Oxidase B (MAO-B) which work hand in hand in the check and balance of the different neurotransmitters of the brain. In patients affected with this disorder, the MAO-B is overexpressed, thereby causing the symptoms of Parkinson’s disease and other neurological abnormalities. The observed increase of MAO-B in patients diagnosed with Parkinson’s has been proposed to be recognized as a biomarker. However, small probes specific for detecting this substance in vivo is currently unavailable. The current probes in the field require the addition of an activating reagent. This may affect the detection of MAO-B by affecting the properties of the enzymes. Still other probes are nonspecific and are not able to identify the difference between MAO-A and MAO-B.
The probe developed by the team in NUS is able to address these problems by developing a small molecular probe which effectively identifies MAO-B specifically. The fluorescent glow it emits is also detectable by a high resolution imaging modality in vivo at up to one millimeter depth.
MAO-B’s potential as a biomarker is reinforced by the finding that the activities of MAO-B are detected in B-lymphocytes, but are lacking in connective tissue cells. Assoc. Prof Lim points out that this highlights the potential of MAO-B as a peripheral biomarker which is readily accessible. Furthermore, he mentioned that this property of MAO-B makes it as a possible indicator for treatment response and disease progression.
Dr. Li Lin, first author of the paper and a post-doctoral fellow in Prof Yao’s lab, said that the findings in this recent study serves as important milestones for the utilization of small probe imaging techniques. Moreover, Lin explains that through further exploration of MAO-B in vivo, further non-invasive imaging diagnostic techniques can be developed.