Mitochondrial proteomic analysis reveals deficiencies in oxygen utilization in medullary thick ascending limb of Henle in the Dahl salt-sensitive rat

Physiol Genomics. 2012 Sep 1;44(17):829-42. doi: 10.1152/physiolgenomics.00060.2012. Epub 2012 Jul 17.

Abstract

The renal medullary thick ascending limb (mTAL) of the Dahl salt-sensitive (SS) rat is the site of enhanced NaCl reabsorption and excess superoxide production. In the present studies we isolated mitochondria from mTAL of SS and salt-resistant control strain SS.13(BN) rats on 0.4 and 8% salt diet for 7 days and performed a proteomic analysis. Purity of mTAL and mitochondria isolations exceeded 93.6 and 55%, respectively. Using LC/MS spectral analysis techniques we identified 96 mitochondrial proteins in four biological mTAL mitochondria samples, run in duplicate, as defined by proteins with a false discovery rate <5% and scan count ≥2. Seven of these 96 proteins, including IDH2, ACADM, SCOT, Hsp60, ATPA, EFTu, and VDAC2 were differentially expressed between the two rat strains. Oxygen consumption and high-resolution respirometry analyses showed that mTAL cells and the mitochondria in the outer medulla of SS rats fed high-salt diet exhibited lower rates of oxygen utilization compared with those from SS.13(BN) rats. These studies advance the conventional proteomic paradigm of focusing exclusively upon whole tissue homogenates to a focus upon a single cell type and specific subcellular organelle. The results reveal the importance of a largely unexplored role for deficiencies of mTAL mitochondrial metabolism and oxygen utilization in salt-induced hypertension and renal medullary oxidative stress.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Blotting, Western
  • Chromatography, Liquid
  • Isocitrate Dehydrogenase / metabolism
  • Loop of Henle / metabolism*
  • Loop of Henle / physiology
  • Mass Spectrometry
  • Microscopy, Fluorescence
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism*
  • Oxygen Consumption / physiology*
  • Proteomics / methods*
  • Rats
  • Rats, Inbred Dahl / genetics
  • Rats, Inbred Dahl / metabolism*
  • Rats, Inbred Dahl / physiology

Substances

  • Mitochondrial Proteins
  • Isocitrate Dehydrogenase