A Comprehensive Approach to Sample Preparation for Electron Microscopy and the Assessment of Mitochondrial Morphology in Tissue and Cultured Cells
Antentor Hinton, Prasanna Katti, Trace Christensen, Margaret Mungai, Jianqiang Shao, Liang Zhang, Sergey Trushin, Ahmad F. Alghanem, Adam Jaspersen, Rachel E. Geroux, Kit Neikirk, Michelle Biete, Edgar Garza-López, Bryanna Shao, Zer Vue, Larry Vang, Heather K. Beasley, Andrea G. Marshall, Dominique Stephens, Steven M. Damo, Jessica Ponce, Christopher K. E. Bleck, Innes Hicsasmaz, Sandra Murray, Ranthony A. C. Edmonds, Andres Dajles, Young Do Koo, Serif Bacevac, Jeffrey L. Salisbury, Renata O. Pereira, Brian Glancy, Eugenia Trushina, E. Dale Abel
Abstract
Mitochondria respond to metabolic demands of the cell and to incremental damage, in part, through dynamic structural changes that include fission (fragmentation), fusion (merging of distinct mitochondria), autophagic degradation (mitophagy), and biogenic interactions with the endoplasmic reticulum (ER). High resolution study of mitochondrial structural and functional relationships requires rapid preservation of specimens to reduce technical artifacts coupled with quantitative assessment of mitochondrial architecture. A practical approach for assessing mitochondrial fine structure using two dimensional and three dimensional high-resolution electron microscopy is presented, and a systematic approach to measure mitochondrial architecture, including volume, length, hyperbranching, cristae morphology, and the number and extent of interaction with the ER is described. These methods are used to assess mitochondrial architecture in cells and tissue with high energy demand, including skeletal muscle cells, mouse brain tissue, and Drosophila muscles. The accuracy of assessment is validated in cells and tissue with deletion of genes involved in mitochondrial dynamics.