Expression and significance of integrin-linked kinase in cultured cells, normal tissue, and diseased tissue of aging rat kidneys.

Integrin-linked kinase (ILK) is an integrin-binding cytoplasmic protein that has been implicated in regulating numerous cellular processes and fibronectin (Fn) deposition through mediated integrin, but the expression and significance of ILK in the aging kidney have not yet been reported. We report here that mRNA and protein expression of ILK increased in primary cultured mesangial and tubular epithelial cells, and normal and unilateral ureteral obstructed kidney tissues in 28-month-old rats but not in 3-month-old rats, moreover, accompanied by the over-expression of Fn and integrin-beta1 in the aging kidney, by means of Northern blot, Western blot, and immunofluorescent double-staining immunohistochemistry. In addition, in the primary cultured kidney cells, ILK expression was positively correlated with senescence-associated beta-gal positive staining and negatively correlated with cellular proliferation. The results suggest that ILK may be involved in the fibrotic or senescent process in the aging kidney.