Showing posts with label Oxidative respiration. Show all posts
Showing posts with label Oxidative respiration. Show all posts

Tuesday, 28 July 2020

Understanding Membrane Permeabilization ...

My initial understanding of how permeabilization worked was that when the permeabilizing agent of recombinant cytolysin protein was injected to create large pores in the leukocytes outer membrane, we would see a normal OXPHOS blueprint from each of the working complexes and a flatline for the impaired complex.


However on reflection, once the leukocytes outer membrane was permeabilized and the cells contents leaked out into the cytosol, there would be no further substrates of any type left in the cell to fuel any of the enzyme complexes CI-CIV.


What I now expect to see is that once the leukocytes membrane is permeabilized, and a specific substrate is injected, the only enzyme complex that will be activated to process the substrate and produce ATP, will be the complex that can oxidise the substrate injected into the cell.



As an example, by selectively injecting succinate we can test complex II’s ability to produce ATP.  Any increase or change in OCR will indicate production of ATP indicating that Complex II is working normally. However if there is no OCR consumption, then Complex II has been identified as impaired suggesting that CII, may be the cause of the PD mitochondrial bioenergetic impairment. This then gives us a target for more specific clinical and pharmaceutical investigation.


Monday, 27 July 2020

Study 1 - Bioenergetic changes ...

The first study will look at analysing changes in bioenergetic levels between Parkinson disease participants (PD)and healthy controls (HC) across differing age groups and by gender.

Initially in this study the levels of mitochondrial oxidative respiration will be measure using a Seahorse XFe-96 to simultaneously measure the oxygen consumption rate (OCR) and changes in glycosylation via the Extracellular Acidification Rate (ECAR).

Both oxygen and glucose are necessary in the production of ATP, so by measuring the OCR & ECAR we can estimate the ATP level of production. By measuring OCR & ECAR for healthy individual over the two age groups (40-50 & 60-70 yrs.), we can set up a benchmark to identify how mitochondrial bioenergetic levels change as individuals age.

These levels can be then used as a benchmark for comparison to the same measures in Parkinson disease participants as they age and also between gender.


Monday, 29 June 2020

OXPHOX XFe-96 well plate design

The Seahorse XFe-96 well plate designs in the confirmation paper were based on comparing just PD samples across different age groups or gender.  In the design below comparisons with the healthy controls (HC) would have been made difficult because the HC sample were planned to be on different plates ie plates for the PD and plates for the HC.



In the updated well plate design we now have both the PD and HC samples for the same age category or gender in the same well plate. This design is better in that both the PD and HC samples are subject to the same treatments in the same XFe-96 test run rather than running two separate plates.

Under the new design, the samples for HC and PD will be prepared at the same time and submitted to the various inhibitors around the same time in the micro-chambers.


Thursday, 20 June 2019

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, CarlĂșcia 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.