EXPRESSION OF HEAT-SHOCK-PROTEIN-47 IS INCREASED IN REMNANT KIDNEY AND CORRELATES WITH DISEASE PROGRESSION

Glomerulosclerosis is characterized by accumulation of the mesangial e xtracellular matrix, including type I and IV collagen. The processing for the collagens in the glomeruli may play a critical role for develo pment of glomerulosclerosis. We examined the expression of heat shock protein 47 (HSP47), a collagen-binding molecular chaperone in the prog resive glomerulosclerosis model. Subtotally nephrectomized rats, unlik e sham-operated rats, developed focal and segmental glomerulosclerosis . Immunological staining demonstrated an increased expression of HSP47 which paralleled the expression of type I and IV collagen in the glom eruli of the nephrectomized rats as the glomerulosclerosis developed. The mRNA levels encoding type I and type IV collagen and HSP47 were in creased 3.4 fold, 3.6 fold and 2.8 fold, respectively, at week 7 after nephrectomy. By in situ hybridization, the expression of HSP47 mRNA w as determined to be localized to the glomeruli with segmental sclerosi s. These results suggest that HSP47 may play a central role in the pro cess of extracellular matrix accumulation during the development of gl omerulosclerosis.