Mitochondrial redox and pH signaling occurs in axonal and synaptic organelle clusters

Michael O. Breckwoldt, Antonis A. Armoundas, Miguel A. Aon, Martin Bendszus, Brian O'Rourke, Markus Schwarzländer, Tobias P. Dick, Felix T. Kurz

Research output: Contribution to journalArticle

Abstract

Redox switches are important mediators in neoplastic, cardiovascular and neurological disorders. We recently identified spontaneous redox signals in neurons at the single mitochondrion level where transients of glutathione oxidation go along with shortening and re-elongation of the organelle. We now have developed advanced image and signal-processing methods to re-assess and extend previously obtained data. Here we analyze redox and pH signals of entire mitochondrial populations. In total, we quantified the effects of 628 redox and pH events in 1797 mitochondria from intercostal axons and neuromuscular synapses using optical sensors (mito-Grx1-roGFP2; mito-SypHer). We show that neuronal mitochondria can undergo multiple redox cycles exhibiting markedly different signal characteristics compared to single redox events. Redox and pH events occur more often in mitochondrial clusters (medium cluster size: 34.1 ± 4.8 μm2). Local clusters possess higher mitochondrial densities than the rest of the axon, suggesting morphological and functional inter-mitochondrial coupling. We find that cluster formation is redox sensitive and can be blocked by the antioxidant MitoQ. In a nerve crush paradigm, mitochondrial clusters form sequentially adjacent to the lesion site and oxidation spreads between mitochondria. Our methodology combines optical bioenergetics and advanced signal processing and allows quantitative assessment of entire mitochondrial populations.

Original languageEnglish (US)
Article number23251
JournalScientific Reports
Volume6
DOIs
StatePublished - Mar 22 2016

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Organelles
Oxidation-Reduction
Mitochondria
Axons
Nerve Crush
Nervous System Diseases
Synapses
Energy Metabolism
Population
Glutathione
Antioxidants
Neurons

ASJC Scopus subject areas

  • General

Cite this

Breckwoldt, M. O., Armoundas, A. A., Aon, M. A., Bendszus, M., O'Rourke, B., Schwarzländer, M., ... Kurz, F. T. (2016). Mitochondrial redox and pH signaling occurs in axonal and synaptic organelle clusters. Scientific Reports, 6, [23251]. https://doi.org/10.1038/srep23251

Mitochondrial redox and pH signaling occurs in axonal and synaptic organelle clusters. / Breckwoldt, Michael O.; Armoundas, Antonis A.; Aon, Miguel A.; Bendszus, Martin; O'Rourke, Brian; Schwarzländer, Markus; Dick, Tobias P.; Kurz, Felix T.

In: Scientific Reports, Vol. 6, 23251, 22.03.2016.

Research output: Contribution to journalArticle

Breckwoldt, MO, Armoundas, AA, Aon, MA, Bendszus, M, O'Rourke, B, Schwarzländer, M, Dick, TP & Kurz, FT 2016, 'Mitochondrial redox and pH signaling occurs in axonal and synaptic organelle clusters', Scientific Reports, vol. 6, 23251. https://doi.org/10.1038/srep23251
Breckwoldt MO, Armoundas AA, Aon MA, Bendszus M, O'Rourke B, Schwarzländer M et al. Mitochondrial redox and pH signaling occurs in axonal and synaptic organelle clusters. Scientific Reports. 2016 Mar 22;6. 23251. https://doi.org/10.1038/srep23251
Breckwoldt, Michael O. ; Armoundas, Antonis A. ; Aon, Miguel A. ; Bendszus, Martin ; O'Rourke, Brian ; Schwarzländer, Markus ; Dick, Tobias P. ; Kurz, Felix T. / Mitochondrial redox and pH signaling occurs in axonal and synaptic organelle clusters. In: Scientific Reports. 2016 ; Vol. 6.
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