Expression of SM22α (transgelin) in glomerular and interstitial renal injury

SM22α, 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 SM22α expression in models of glomerular and interstitial renal injury.

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 SM22α expression were performed.

In the 5/6 Nx model, SM22α was first expressed in peritubular interstitial cells and was also expressed in injured glomerular epithelial cells at 8 weeks. In the I/R model, SM22α expression was induced in peritubular interstitial cells as early as 12 h after I/R with expression sustained at 7 days. However, SM22α was not detected in any glomerular cells or tubular epithelial cells. In PAN nephrosis, SM22α was only expressed in glomerular epithelial cells after 1 week, but expression was transient.

SM22α was expressed in glomerular epithelial cells and interstitial cells in renal injury. SM22α is differentially upregulated in various models of renal injury and merits further study.