EXPRESSION OF HEAT-SHOCK-PROTEIN-27 IN DEVELOPING AND ADULT HUMAN KIDNEY

The expression of heat shock protein (hsp) 27 was examined in the deve loping and adult human kidney. Immunolocalization using a monoclonal a ntibody against human hsp 27 demonstrated immunoreactivity in both the developing and adult kidney, Low to moderate immunoreactivity for hsp 27 was observed in the fetal and adult proximal tubule, distal tubule , and mesangial cells of the glomeruli, Intense immunoreactivity for h sp 27 was localized to the cortical and medullary collecting ducts in both the adult and fetal kidney, with the most intense staining in the medullary regions, The loop of Henle demonstrated no immunoreactivity for hsp 27. The blastemal element of the developing kidney showed no hsp 27 immunostaining and the ureteric bud demonstrated moderate stain ing. Western, northern, and reverse transcription-polymerase chain rea ction (RT-PCR) analyses disclosed no significant differences in hsp 27 mRNA or protein level as a function of gestational age. An analysis o f the phosphorylation state of hsp 27 showed the majority of hsp 27 to be present in the unphosphorylated isoform for both adult and fetal s amples. These studies are the first to demonstrate the presence of hsp 27 in the human kidney. It is suggested that this pool of hsp 27 is c onstitutive as it appears in an inactivated state; localized to the cy toplasm and in an unphosphorylated state.