Abstract: FR-PO180

Super Resolution Imaging of Kidney Tissue Is a Novel Technique to Study Three Dimensional Mitochondrial Networks and Functional Correlates In Vivo

Session Information

  • Mitochondriacs and More
    November 03, 2017 | Location: Hall H, Morial Convention Center
    Abstract Time: 10:00 AM - 10:00 AM

Category: Cell Biology

  • 201 Cell Signaling, Oxidative Stress

Authors

  • Brooks, Craig R., Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Taguchi, Kensei, Department of Nephrology and Hypertension, Nashville, Tennessee, United States
Background

Mitochondria are essential for all eukaryotic life. Kidney proximal tubule cells (PTCs) have the highest content of mitochondria, by surface area, of any cell type in mammals. The large complement of mitochondria is necessary to support the tremendous amount of transport that occurs in the PTC during the reabsorption of sodium and other solutes from urine. Previous studies have demonstrated that mitochondrial morphology is important to maintain both the health and functionality of mitochondria.

Methods

Sham or ischemically injured kidneys from wild-type C57BL/6 mice were fixed and embedded in paraffin following standard protocols. Sections of the kidneys were mounted on (3-Aminopropyl)trimethoxysilane treated coverslips and stained for mitochondrial and PTC markers, and then imaged by Structured Illumination Microscopy (SIM) or Zeiss Airyscan.

Results

Super resolution imaging enabled the resolution of not only individual mitochondria but also distinguished inner membrane space vs. outer membrane. SIM revealed that PTC mitochondria form a 3D network in vivo. Mitochondrial networks extend throughout the cell body and into the interdigitations of the PTCs. Co-staining of mitochondrial makers with Na+-K+-ATPase revealed a tight association of the mitochondria with interdigitations of the basolateral membrane in PTCs, in which mitochondria from one PTC often run parallel to the mitochondria of neighboring cells within Na+-K+-ATPase positive inholdings of the plasma membrane. Injury to the kidney led to reduced mitochondrial interconnectivity and rearrangement of the inner membrane space. Injury also resulted in retraction of the basolateral interdigitations of the plasma membrane.

Conclusion

Super resolution imaging provides a novel approach to analyze individual mitochondria and inner vs. outer membrane structure in vivo and provides a 3D morphological analysis of the cell and mitochondrial network. Individual mitochondria that extend through interdigitations of the PTCs are part of a larger network that extends through the cell body. Injury to the kidney leads to a breakdown of this network and disassociation of mitochondria from the basolateral membrane.

Funding

  • NIDDK Support