Expression of SM22α (Transgelin) in Glomerular and Interstitial Renal Injury

Background/Aims: SM22 alpha, transgelin, is abundantly expressed in smooth muscle tissues and our previous work demonstrated that it is a novel marker of injured glomerular epithelial cells in rat antiglomerular basement membrane nephritis. In this study, we investigated SM22 alpha expression in models of glomerular and interstitial renal injury. Methods: The 5/6 nephrectomy (Nx) model, ischemia-reperfusion (I/R) model and puromycin aminonucleoside (PAN) nephrosis of rats were studied. Immunohistochemical analyses and immunoelectron microscopic studies of SM22 alpha expression were performed. Results: In the 5/6 Nx model, SM22 alpha was first expressed in peritubular interstitial cells and was also expressed in injured glomerular epithelial cells at 8 weeks. In the I/R model, SM22 alpha expression was induced in peritubular interstitial cells as early as 12 h after I/R with expression sustained at 7 days. However, SM22 alpha was not detected in any glomerular cells or tubular epithelial cells. In PAN nephrosis, SM22 alpha was only expressed in glomerular epithelial cells after 1 week, but expression was transient. Conclusion: SM22 alpha was expressed in glomerular epithelial cells and interstitial cells in renal injury. SM22 alpha is differentially upregulated in various models of renal injury and merits further study. Copyright (C) 2010 S. Karger AG, Basel