SUIT-008 O2 pfi D014

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SUIT-008 O2 pfi D014

Description

1PM;2D;2c;3G;4S;5U;6Rot;7Ama;8AsTm;9Azd.png


Reference: A - Lemieux 2017 Sci Rep - SUIT-008

SUIT number: D014_1PM;2D;2c;3G;4S;4D;5U;6Rot;7Ama;8AsTm;9Azd

O2k-Application: O2

MitoPedia: SUIT - O2 pfi D014 protocol was used a a reference protocol in MitoEAGLE project (WG2) to evaluate the researcher skills preparing permeabilized fibers
SUIT protocol pattern: 1PM;2D;3G;4S;5U;6Rot

The SUIT-008 O2 pfi D014 protocol is designed to assess the additivity between the N- and S-pathway in the Q-junction, providing a physiologically relevant estimate of maximum mitochondrial respiratory capacity in permeabilized fibers. It also serves as a diagnostic tool for the activity of the glutamate dehydrogenase and its linked pathways, which could be relevant in some pathologies. SUIT-008 O2 pfi D014 can be easily extended with the CIV assay module.

Communicated by Huete-Ortega M, Iglesias-Gonzalez J and Gnaiger E (last update 2019-06-06)

Representative traces

D014 O2 traces.png

MitoPedia: SUIT

Steps and respiratory states

SUIT-008

Step State Pathway Q-junction Comment - Events (E) and Marks (M)
1PM PML(n) N CI 1PM
2D PMP N CI 1PM;2D
2c PMcP N CI 1PM;2D;2c
  • NADH-linked substrates (type N-pathway to Q).
  • Addition of cytochrome c yields a test for integrity of the mtOM. Stimulation by added cytochrome c would indicate an injury of the mtOM and limitation of respiration in the preceding state without added c due to loss of cytochrome c. Typically, cytochrome c is added immediately after the earliest ADP-activation step (P, OXPHOS-capacity with saturating [ADP]).
  • OXPHOS capacity, P (with saturating [ADP]), active OXPHOS state.
3G PGMP N CI 1PM;2D;2c;3G
4S PGMSP NS CI&II 1PM;2D;2c;3G;4S
  • Respiratory stimulation by simultaneous action of type N substrates & succinate, with convergent electron flow in the NS-pathway for reconstitution of TCA cycle function.
  • OXPHOS capacity, P (with saturating [ADP]), active OXPHOS state.
5U PGMSE NS CI&II 1PM;2D;2c;3G;4S;5U
6Rot SE S CII 1PM;2D;2c;3G;4S;5U;6Rot
7Ama ROX 1PM;2D;2c;3G;4S;5U;6Rot;7Ama
  • Rox is the residual oxygen consumption in the ROX state, due to oxidative side reactions, estimated after addition of Antimycin A (inhibitor of CIII). Rox is subtracted from oxygen flux as a baseline for all respiratory states, to obtain mitochondrial respiration (mt).
Step Respiratory state Pathway control ET-Complex entry into Q-junction Comment
## AsTm AsTmE CIV CIV
## Azd ROX


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Strengths and limitations

+ NS-OXPHOS capacity provides a physiologically relevant estimate of maximum mitochondrial respiratory capacity.
+ The presence of PGM and S establishes fully operative TCA cycle activity.
+ This protocol allows to analyse the convergence of pathways at the Q-junction (N, NS, S).
+ Mitochondrial external membrane can be measured with the addition of cytochrome c. Application of the cytochrome c test early in the protocol ensures comparability of all states in case of any effect of c.
+ Reasonable duration of the experiment.
+ Complex IV activity can be measured.
+ GM and PM yield typically identical fluxes in human skeletal muscle fibres. However, PM is the superior alternative to GM: the fraction of the N-pathway is lower and of the S-pathway is higher with GM compared to PM (GMP is inhibited by the CII inhibitor malonic acid to a larger extent than PMP). PM, therefore, yields a more sensitive assay for the diagnosis of injuries in the N-pathway, since an impairment of N-pathway capacity can be compensated partially by activation of the S-pathway. This is an advantage compared to SUIT-011 for diagnosis of N-capacity.
- Fatty acid oxidation is not analysed.
- When evaluating the additive effect of the N- and S-pathway, it has to be considered that NSP- and NSE-capacities can only be compared with NP- and SE-capacities. This is not a problem when NSP = NSE (Gnaiger 2009). In this case, it may be assumed that SP = SE (Votion et al 2012), such that NSP can be compared with NP + SP. SUIT-004 should be chosen for the additive effect in the ET-state.
- Careful washing is required after the experiment to avoid carry-over of inhibitors and uncoupler.

Compare SUIT protocols

  • SUIT-004 1PM;2D;3U;4S;5Rot- The SUIT-004 protocols provide a quick assessment of the linear coupling control (L- P- E) with NADH linked-substrates (PM) and the control in ET state (N, NS, S)
  • SUIT-011 1GM;2D;3S;4U;5Rot- The SUIT-011 protocols are designed to study physiologically relevant maximum mitochondrial respiratory capacity (OXPHOS with NS substrates) and coupling/pathway control.

References

 YearReferenceOrganismTissue;cell
Votion 2012 PLoS One2012Votion DM, Gnaiger E, Lemieux H, Mouithys-Mickalad A, Serteyn D (2012) Physical fitness and mitochondrial respiratory capacity in horse skeletal muscle. PLoS One 7:e34890.HorseSkeletal muscle


MitoPedia concepts: SUIT protocol, SUIT A, Find 


MitoPedia methods: Respirometry