Study 4 - Early Bio-marker for Parkinson’s Disease ... An update

Out of each of the studies I have planned, trying to utilise the data and information that I have learnt from the other studies together in such a way that we may highlight particular patterns that are linked with early cognitive or motor declines that can be potentially used as an early bio-marker is the hardest to draw to a conclusion that seems to make sense.

My current thinking is that we can't simply analyse the proteomic results, find particular protein aberrations, then analyse a younger sample ie 30 year olds, to see if the same proteins are showing any form of change or impairment. The problem is that the sample may be taken randomly from a younger person who may never go on to develop any form of neurodegenerative disease.

So how to overcome this dead end issue. We know from other studies that mitochondrial disease is definitely linked to other diseases such as coronary, vascular disease, diabetes, schizophrenia etc. which also have a higher correlation of being linked as comorbid diseases with Parkinson's disease.

By the time someone presents with Parkinson's they have already lost around 80% of their dopaminergic neurons, and research has indicated that this damage has been occuring over a period of upto 15 years. So if we can we identify a younger sample from individuals already showing signs of these other comorbid diseases and take our samples from this cohort, then this may increase the probability that some of the cohort will go on to develop Parkinson's in the future. An alternative tho this would be to run a cognitive battery of tests over the younger cohort and use samples that show cognitive changes compared to the test norm. 

Applications of mass spectrometry-based proteomics in research Workshop

Registered for the Applications of mass spectrometry-based proteomics in research workshop to be held on Friday 26th 2020. I did this course last year, but not having read up on proteomics, the information was a little confusing and hard to assemble into a logical process workflow.

It is now anticipated that I will include Label Free Liquid Chromatography and Mass Spectrometry into my research program to investigate the differences in protein content, abundance and structure between age and gender matched Parkinson's disease patients and healthy controls.

Abnormal serum concentrations of proteins in Parkinson’s disease

Comparative proteomics of serum samples of PD patients and controls

Blood proteins are constantly changing in response to metabolic processes going on in the body which are also influenced by environmental factors. Because blood contains a wealth of proteins and dynamically changes it is an excellent source of information to analyse disease progression. Research by Goldknopf, (2009), found : 

"... alterations in 21 proteins belonging to different categories such as cell degeneration, oxidative stress, and inflammation. Out of these, 11 proteins were abnormally expressed only in the patients having mild symptoms and 14 in moderate-to-severe PD stage which shows that the proteome component of blood responds to disease severity (Goldknopf et al. 2009)..."

Goldknopf, I. L., Bryson, J. K., Strelets, I., Quintero, S., Sheta, E. A., Mosqueda, M., . . . Markopoulou, K. (2009). Abnormal serum concentrations of proteins in Parkinson's disease. Biochemical and biophysical research communications, 389(2), 321-327. doi:10.1016/j.bbrc.2009.08.150

Proteomic analysis shows PD mitochondria are upregulated

Starting to make some progress on understanding how proteomic analysis may work. The attached article has some interesting points:

1. proteomic results for upregulated Mitochondria, oxidative stress, and energy metabolism in SNpC
2. proteomic results for upregulated Inflammation, phagocytosis, cell signalling in blood plasma
3. “… Proteomic analysis of SN region of human brain demonstrated upregulation of mitochondrial complex III, ATP synthase D, complexin I, profilin, L-type calcium channel δ-subunit, and fatty acid-binding protein in PD patients in comparison to control subjects. These results provide the evidence of disrupted mitochondrial and antioxidant function in PD (Basso et al. 2004). Two other proteomic studies utilizing SN region of PD patients also confirmed the involvement of mitochondrial dysfunction, cytoskeleton impairment, and oxidative stress in PD pathogenesis (Kitsou et al. 2008; Licker et al. 2012)…”
4. “… mitochondria are the most studied organelle for understanding PD pathogenesis and are known to play a central role in PD pathology. A number of proteins related to disease such as PINK1, DJ-1, and parkin are either localized inside or interact with mitochondria, and death of dopaminergic neurons is caused due to induction of oxidative stress and apoptotic pathways involving mitochondria (Nicotra and Parvez 2002; Dixit et al. 2013). However, only a single proteomic study has been conducted on the mitochondrial fraction of the SN region of the PD brain, which demonstrated that 119 out of 842 identified proteins were significantly different in their relative abundance in comparison to age-matched controls…”

Each of these points seem to suggest that proteomic analysis of PD patients found changes to mitochondrial proteins were upregulated in all cases and in the case of oxidative stress and inflammation the proteins were also up[regulated.

Dixit, A., Mehta, R., & Singh, A. K. (2019). Proteomics in Human Parkinson's Disease: Present Scenario and Future Directions. Cellular & Molecular Neurobiology, 39(7), 901-915. 

Search for competing research

A search of the PROSPERO International prospective register of systematic reviews found only one close review to my proposed work.

Topic: Analysis of neuroinflammatory cell mechanisms associated with neurodegenerative
process in Parkinson's disease: a systematic review

Proposed by: Mirian David, Renaly Rodrigues, Carlúcia Franco, Clarissa Bezerra

Review question: What are the neuroinflammatory cellular mechanisms associated with the neurodegenerative process in Parkinson's Disease?

The main key difference is that Mirian et.al. are investigating how the immune response of astrocytes and microglia are showing up in post mortem brain slices, whilst we are proposing to look at changes and mutations in protein structures and mitochondria in neural cells using proteomics and Seahorse oxidative respiration analysis.

Document link:

PROSPERO Link for Analysis of neuroinflammatory cell mechanisms: A systematic Review