|News and Events||Working Groups||Short-Term Scientific Missions||Management Committee||Members|
COST Action CA15203 (2016-2021): MitoEAGLE
Evolution-Age-Gender-Lifestyle-Environment: mitochondrial fitness mapping
MitoPedia topics: EAGLE
COST WG2: WG2
|Institution||Manchester Metropolitan University, UK|
|Address||John Dalton Building Chester Street, M1 5GD|
|Eggelbusch 2022 Abstract Bioblast||2022||7.1. «5 min» https://doi.org/10.26124/bec:2022-0001|
|Giakoumaki 2019 MiPschool Coimbra||2019|
MitoEAGLE Short-Term Scientific Mission
- Work Plan summary
- 1. Aim and motivation – Please explain the scientific and/or other motivation for the STSM and what scientific and/or other outcomes you aim to accomplish with the STSM
- Mitochondrial function and neuromuscular junction (NMJ) integrity are compromised in neuromuscular diseases, ageing and conditions associated with skeletal muscle wasting (i.e. in microgravity conditions during space flight, chronic diseases and bed-rest during hospitalisation). Although the exact link between NMJ integrity, skeletal muscle wasting and mitochondrial dysfunction remains unknown, previous studies indicated that mitochondrial dysfunction via ROS generation and induction of AMPK-FoxO3 signalling activates proteolysis (Powers et. al. 2012). Particularly, ROS generation could compromise the integrity of the NMJ and thereby the neuromuscular interaction. Countermeasures to ameliorate mitochondrial dysfunction could thus prove to be a novel approach to protect NMJ integrity and attenuate skeletal muscle weakness and atrophy.
- In a large NASA/ESA-supported bed rest study run in Cologne in 2019, we have the opportunity to measure mitochondrial respiration in skeletal muscle biopsies from human participants undergoing a 60-day bed rest (to mimic microgravity). Specifically, we will assess mitochondrial integrity and function in biopsies taken from the vastus lateralis muscle before and after 5 and 60 days of bed rest. In half of the participants the efficacy of daily centrifugation to prevent or attenuate the bed rest-induced muscle wasting, loss of NMJ integrity and mitochondrial dysfunction will be assessed.
- We hypothesize that 1) mitochondrial dysfunction during inactivity is linked to degradation of the intermediate filament protein desmin and loss of acetylcholine receptor (AChR) anchoring that compromises the neuromuscular interaction and 2) that daily centrifugation during bed rest ameliorates mitochondrial dysfunction and therefore ensures NMJ integrity.
- In order to test these hypotheses, I have the opportunity to perform high-resolution respirometry (by OROBOROS Oxygraph-2k), but currently lack the skills to perform these measurements. To fully capitalise on this opportunity, this STSM gives me the chance to learn high-resolution respirometry in the lab of Dr Wüst, whose lab has been awarded the ‘Reference laboratory for mitochondrial function (MiPNet)’ at the VU University in Amsterdam.
- Work Plan summary
- 2. Proposed contribution to the scientific objectives of this Action
- The “L” within “MitoEAGLE” stands for lifestyle. Activity and inactivity are major lifestyle components that are studied in great detail within the consortium. Here, I have the unique opportunity to perform high-resolution respirometry in vastus lateralis biopsies from humans undergoing long-term bed rest. These experiments will be performed in close collaboration with the current ongoing human skeletal muscle study (with Dr Pablo Garcia-Roves amongst others) as part of work package 2. Preliminary results of the study will be shared with consortium members during upcoming MitoEAGLE meetings.
- 3. Techniques – Please detail what techniques or equivalent you may learn to use, if applicable
- To test the hypotheses described above, a portion of the muscle biopsy obtained from the vastus lateralis muscle will be used for assessment of mitochondrial respiration by high-resolution OROBOROS respirometry. This platform is a state-of-the-art instrument that allows the assessment of mitochondrial function in small tissue samples. In order to ensure accurate analysis and high-quality results, training on the operation of the OROBOROS instrument is required.
- Sample preparation will be a crucial part of the training. A longitudinal 1-1.5 mm bundle of the muscle biopsy will be removed and mechanically separated into bundles of 5-10 muscle fibres that remain connected at least on one end, forming a “mesh-like” structure. Such small muscle bundles allow proper permeabilisation of the muscle tissue, a requirement for respirometry. To achieve appropriate preparation of the tissue sample, training will be required, which will be provided by the host institution.
- 4. Planning – Please detail the steps you will take to achieve your proposed aim
- To ensure optimal preparation of the human biopsy samples and high-quality performance and analysis of mitochondrial respiration, appropriate training must have taken place before the start of the study. Training will include muscle bundle preparation, use and maintenance of OROBOROS Oxygraph-2K instrument, preparation of solutions necessary for use in the respirometry experiments and test runs using rodent skeletal muscle tissue. The training will also include discussion and illustration of potential problems and pitfalls and how to recognise and tackle them. I will also be taught how to analyse and interpret results by Dr Wüst, in close collaboration with other members of the MitoEAGLE consortium. This will ensure optimal preparation to deal with unforeseen eventualities. I have the privilege to be given the opportunity to be taught by Dr Wüst who has a wealth of experience using the OROBOROS instruments, as reflected by published papers and the status of his lab as a ‘Reference Laboratory for Mitochondrial Physiology (MiPNet)’, that is well embedded in the MitoEAGLE consortium. I will be in his lab for two weeks for fulltime training, after which Dr Wüst will join me during the first week of experiments in Cologne.