Volani 2015 Abstract IOC106

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Volani C, Haschka D, Demetz E, Doerrier C, Gnaiger E, Weiss G (2015) Determination of mitochondrial respiration in peripheral blood mononuclear cells. Mitochondr Physiol Network 20.10.

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Volani C, Haschka D, Demetz E, Doerrier C, Gnaiger E, Weiss G (2015)

Event: IOC106 Schroecken

Mitochondria are dynamic organelles, involved in fundamental cell processes, including oxidative phosphorylation [1,2]. Iron plays a decisive role in these processes because it is central part of mitochondrial enzyme complexes but also regulates citric acid cycle activity by modulating mitochondrial aconitase expression. Hence, imbalances of iron homeostasis impact on mitochondrial activity and, thus, on cell and organ functions [3]. So far, little information is available on how to best measure mitochondrial activity and its interaction with iron homeostasis in vivo; therefore we questioned whether determination of mitochondrial respiration in peripheral blood mononuclear cells (PBMCs) could be a good surrogate marker for that.

Human PBMCs were collected from buffy coats, purified cells (2x10^6 cells/ml) were resuspended in mitochondrial respiration medium (MiR05), and mitochondrial activity was assessed by high resolution respirometry (Oroboros Instruments, Austria). Moreover, to access the impact of iron on mitochondrial respiration we studied mitochondrial respiration in hearts and livers of mice, receiving either iron deficient- or standard iron-diet one week before being sacrificed. Organs were collected and stored in Custadiol prior to homogenization in MiR05. Mitochondrial routine respiration, complex I and II maximal oxidative phosphorylation together with non-coupled respiration of the homogenates were assessed at a final concentration between 1 and 2 mg.

Our ongoing experiments indicate that mitochondrial function testing can be successfully performed in human PBMCs as well as in mouse tissues. Analyses of organ samples from mice indicate that dietary iron supplementation leads to enhanced oxidative phosphorylation. Furthermore, it is plausible to hypothesize that PBMCs mitochondrial activity can reflect this organ increase. In conclusion, the use of high-resolution respirometry (Oroboros Instruments, Austria) represents a powerful and reliable tool to investigate mitochondrial respiration in PBMCs and tissues, and to systemically study the effects of iron homeostasis on mitochondrial function. Moreover, determination of mitochondrial function in PBMCs might provide useful information on mitochondrial activity in tissues.

Keywords: PBMC

O2k-Network Lab: AT Innsbruck Oroboros, ES Granada Acuna-Castroviejo D, AT Innsbruck Gnaiger E, AT Innsbruck MitoCom


Labels: MiParea: Respiration, Instruments;methods, Exercise physiology;nutrition;life style 


Organism: Human, Mouse  Tissue;cell: Heart, Liver, Blood cells, Lymphocyte  Preparation: Intact cells, Homogenate 


Coupling state: ROUTINE, OXPHOS, ET  Pathway: N, S  HRR: Oxygraph-2k 


References

  1. Karabatsiakis A, Böck C, Salinas-Manrique J, Kolassa S, Calzia E, Dietrich DE, Kolassa IT (2014) Mitochondrial respiration in peripheral blood mononuclear cells correlates with depressive subsymptoms and severity of major depression. Transl Psychiatry 4:e397.
  2. Horowitz MP, Greenamyre JT (2010) Mitochondrial iron metabolism and its role in neurodegeneration. J Alzheimers Dis 20 Suppl 2:S551-68.
  3. Lakhal-Littleton S, Wolna M, Carr CA, Miller JJ, Christian HC, Ball V, Santos A, Diaz R, Biggs D, Stillion R, Holdship P, Larner F, Tyler DJ, Clarke K, Davies B, Robbins PA (2015) Cardiac ferroportin regulates cellular iron homeostasis and is important for cardiac function. PNAS 112:3164-9.

Affiliations

1-Dept Internal Medicine VI, Medical Univ Innsbruck; 2-Oroboros Instruments, Innsbruck, Austria