Autophagy in chronically ischemic myocardium

作者：Lin Yan, Dorothy E. Vatner, Song‐Jung Kim, Hui Ming Ge, Malthi Masurekar, William H. Massover, Guiping Yang, Yutaka Matsui, Junichi Sadoshima, Stephen F. Vatner · 发表于：Proceedings of the National Academy of Sciences · 年份：2005 · DOI：10.1073/pnas.0506843102 · 被引用次数：498 · 研究领域：Autophagy in Disease and Therapy、Calpain Protease Function and Regulation、Endoplasmic Reticulum Stress and Disease

We tested the hypothesis that chronically ischemic (IS) myocardium induces autophagy, a cellular degradation process responsible for the turnover of unnecessary or dysfunctional organelles and cytoplasmic proteins, which could protect against the consequences of further ischemia. Chronically instrumented pigs were studied with repetitive myocardial ischemia produced by one, three, or six episodes of 90 min of coronary stenosis (30% reduction in baseline coronary flow followed by reperfusion every 12 h) with the non-IS region as control. In this model, wall thickening in the IS region was chronically depressed by approximately 37%. Using a nonbiased proteomic approach combining 2D gel electrophoresis with in-gel proteolysis, peptide mapping by MS, and sequence database searches for protein identification, we demonstrated increased expression of cathepsin D, a protein known to mediate autophagy. Additional autophagic proteins, cathepsin B, heat shock cognate protein Hsc73 (a key protein marker for chaperone-mediated autophagy), beclin 1 (a mammalian autophagy gene), and the processed form of microtubule-associated protein 1 light chain 3 (a marker for autophagosomes), were also increased. These changes, not evident after one episode, began to appear after two or three episodes and were most marked after six episodes of ischemia, when EM demonstrated autophagic vacuoles in chronically IS myocytes. Conversely, apoptosis, which was most marked after three episodes, decreased strik...