HSP27 regulation in acute unilateral obstructed kidney, along with RMIC and collecting duct cells subjected to mechanical, oxidative, and inflammatory stress

Abstract

In vivo, renal medullary interstitial cells (RMIC) and collecting duct (CD) cells are subjected to mechanical, oxidative and inflammatory stress as a result of ureteral obstruction. Heat shock protein 27 (HSP27) is expressed in RMIC and CD cells in vivo and in vitro, and plays a role in stabilization of actin filaments. Both HSP27 and the phosphorylated‐form (pHSP27) have anti‐apoptotic functions.In vivo studies using rats subjected to acute unilateral ureteral obstruction (UUO) for 6h and 12h showed unchanged HSP27 protein level in kidney inner medulla (IM). pHSP27 protein level was increased in obstructed kidney IM compared to both sham and contralateral kidney. Further examination of HSP27 protein abundance in response to mechanical, oxidative, and inflammatory stress in vitro, we subjected RMIC and CD cell to pressure, H2O2 and interleukin 1â (IL‐1â) stimulation for 2–24h. Applying oxidative stress to RMIC and CD cells increased HSP27. Inflammatory stress with IL‐1â increased HSP27 and pHSP27. Pressure of 60 mmHg was explored directly in RMIC which increased HSP27.These data indicates that in response to acute UUO different forms of cellular stress increase expression of HSP27 and pHSP27, which may play a role in the cytoprotection of RMIC and CD cells.