Plecita-Hlavata 2013 Abstract MiP2013

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Plecita-Hlavata L, Engstova H, Spacek T, Alan L, Stradalova V, Malinsky J, Jezek P(2013) Mitochondrial network and cristae remodeling upon hypoxia. Mitochondr Physiol Network 18.08.
Link:
Lydie Plecita-Hlavata
MiP2013, Book of Abstracts Open Access

Plecita-Hlavata L, Engstova H, Spacek T, Alan L, Stradalova V, Malinsky J, Jezek P (2013)

Event: MiPNet18.08_MiP2013

We have observed thinning of mitochondrial matrix space (mtMS) at negligible changes of mitochondrial outer membrane (mtOM) tubules in HepG2 cells during hypoxic adaptation at 5% oxygen by means of various methods such as 3D high-resolution 4Pi microscopy, 3D super-resolution fluorescent photo-activated localization (BiplaneFPALM) microscopy [1] and cryo-electron microscopy (EM). This phenotype is hypoxia-induced-factor– (HIF–) dependent (maximal HIF1alpha stabilization is around 5th hour in hypoxia [2,3]) and is independent of the type of energy metabolism, i.e. sole aerobic glycolysis (glycemic cells) or oxidative phosphorylation (OXPHOS cells). More extensive mtMS shrinkage inside the mtOM reflected the expansion of intermembrane space (IMS), documented by EM as shrinkage of matrix space of cristae in parallel to IMS visualization using Eos-conjugated truncated lactamase-#. This remodelation proceeded along the predominant length of mitochondrial network tubules. The hypoxic IMS expansion resembles Hackenbrock’s classic observation of condensed cristae conformation for isolated mitochondria at phosphorylating state OXPHOS, however it is not encountered in situ [4]. Confirmation of paradoxical observations of orthodox cristae, in cells undoubtedly phosphorylating in atmospheric conditions, were observed by electron microscopy. The mitochondria had more shrunken IMS and expanded mtMS. In turn, upon hypoxia, the IMS expansion reflected the established Hackenbrock’s condensed cristae conformation [5]. We suggest that easier oxygen diffusion throughout the expanded IMS benefits the cells upon hypoxic adaptation.


O2k-Network Lab: CZ Prague Jezek P


Labels: MiParea: mt-Structure;fission;fusion, mt-Membrane 

Stress:Ischemia-reperfusion 





MiP2013 

Affiliations and author contributions

1 - Institute of Physiology, Academy of Sciences, Prague, Czech Republic; 2 - Microscopy unit, Institute of Experimental Medicine, Academy of Sciences, Prague, Czech Republic. - Email: plecita@biomed.cas.cz

Supported by GACR grant P302/10/0346 (to JP) and Czech Ministry of education LH11055 (to PHL).


References

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  2. Semenza GL (2007) Oxygen-dependent regulation of mitochondrial respiration by hypoxia-inducible factor 1. Biochem J 405: 1–9.
  3. Ježek P, Plecitá-Hlavatá L, Smolková K, Rossignol R (2010) Distinctions and similarities of cell bioenergetics and role of mitochondria in hypoxia, cancer, and embryonic development. Int J Biochem Cell Biol 42: 604–622.
  4. Sun MG, Williams J, Munoz-Pinedo C, Perkins GA, Brown JM, Ellisman MH, Green DR, Frey TG. (2007) Correlated three-dimensional light and electron microscopy reveals transformation of mitochondria during apoptosis. Nat Cell Biol 9: 1057–1065.
  5. Hackenbrock CR (1966) Ultrastructural bases for metabolically linked mechanical activity in mitochondria. I. Reversible ultrastructural changes with change in metabolic steady state in isolated liver mitochondria. J Cell Biol 30: 269–297.