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Publications

Journal Article Preprint Epublish

PubMed: 40654983 DOI: 10.1101/2025.05.05.652276

A Platform for Mitochondrial Profiling in Enriched Kidney Segments Under Thermodynamic Control.

bioRxiv

Authors: Stephen T Decker, Precious C Opurum, Ran Hee Choi, Venisia L Paula, Anu S Kurian, Deborah Stuart, Linda S Nikolova, Alejandro Sanchez, Laith Al-Rabadi, Nirupama Ramkumar, Kelsey H Fisher-Wellman, Katsuhiko Funai

Affiliations

  • Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah.
  • Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah.
  • Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah. Department of Kinesiology, University of Utah, Salt Lake City, Utah. Haumana 'O Pasifika Program, University of Utah, Salt Lake City, Utah.
  • Division of Nephrology and Hypertension, University of Utah School of Medicine, Salt Lake City, Utah.
  • Electron Microscopy Core Facility; University of Utah; Salt Lake City, UT; USA.
  • Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, Utah, USA.
  • Huntsman Cancer Institute, Cancer Hospital, Salt Lake City, Utah, USA.
  • Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.

Abstract

Mitochondrial function varies widely across kidney nephron segments, yet conventional approaches lack the resolution and control needed to assess cell-type-specific bioenergetics in situ. We present a methodological platform that enables segment-resolved profiling of mitochondrial respiration, conductance, and membrane potential in freshly isolated mouse nephron segments. Combining mechanical sieving and adhesion-based enrichment with permeabilized high-resolution respirometry, we adapted the creatine kinase clamp to quantify oxygen flux and mitochondrial membrane potential across defined free energies. Using this approach, we found that proximal tubules exhibit high respiratory conductance and dynamic mitochondrial polarization, while distal tubules and glomeruli maintain static membrane potential and low conductance. In a model of adenine-induced nephropathy, only proximal tubule mitochondria showed marked reductions in respiration and ATP production. This segment-specific dysfunction was not detectable in bulk mitochondrial isolates. Our approach provides thermodynamically anchored, segment-resolved insight into mitochondrial adaptation under physiological and pathological conditions. It is broadly applicable to other tissues with metabolic heterogeneity and compatible with disease models, genetic tools, and pharmacological interventions. This platform bridges a critical gap between conventional respirometry and functional mitochondrial phenotyping in native tissue structures.

MeSH

Nephrons, Respiration, Membrane Potentials, Mitochondria, Kidney, Tissues, Membranes