New findings on protein expression in copper deficient rat heart using proteomic approaches

Abstract

Dietary Cu-deficiency not only causes a hypertrophic cardiomyopathy but also increases cancer risk in rodent models. The present studies were undertaken to determine the effect of Cu-deficiency on protein profiles in rat heart tissue. Male Sprague-Dawley rats were fed diets that were either copper adequate (6.0 μg copper/g diet n = 6) or copper deficient (0.3 μg copper/g diet n = 6) for 5 wk. An approach using liquid chromatography mass spectrometry analysis coupled with DNA gel shift and immunodection dot blotting revealed a 132 kDa protein complex in the protein extract from hearts of Cu-deficient, but not Cu-adequate rats. This complex contained a collagen alpha (I) chain precursor as well as a leucine-rich protein 130 (DNA binding protein). These data suggest that Cu-deficiency may have a potential to influence DNA stability and mRNA transcript processing. Another approach to determine the effect of Cu deficiency on protein profiles used the combination of the isotope-coded affinity tag (ICAT) method and Western blotting analysis. ICAT analysis suggested that protein profiles from heart tissue of Cu-deficient rats were different from those of Cu-adequate rats; seven major protein species differed by more than a 100% increase or a 50% decrease. Western blotting analysis confirmed an 85% increase in fibulin-5 (also known DANCE/EVEC) in Cu-deficient rat heart, and suggested a critical biological function of Cu in controlling vascular redox state, scaffolding of cells to elastic fiber, and preventing elastinopathy in the rat heart.