Overexpression of the human 72 kDa heat shock protein in renal tubular cells confers resistance against oxidative injury and cisplatin toxicity

T cells reactive against immunodominant regions of inducible heat shock proteins (HSPs) have been identified in the chronic inflammatory lesions of several experimental autoimmune diseases. Since HSPs are known to be induced by a number of renal tubular epithelial cell toxins associated with chronic interstitial nephritis, we investigated the relevance of HSP expression and T cell reactivity to HSP70 in a model of progressive inflammatory interstitial nephritis. Chronic administration of cadmium chloride (CdCl2) to SJL/J mice induces HSP70 expression in renal tubular cells 4-5 wk before the development of interstitial mononuclear cell infiltrates. CdCl2 also induces HSP70 expression in cultured tubular epithelial cells from SJL/J mice. CD4+, TCR-alpha/beta+ T cell lines specific for an immunodominant HSP peptide are cytotoxic to heat stressed or CdCl2-treated renal tubular cells. Such HSP-reactive T cells mediate an inflammatory interstitial nephritis after adoptive transfer to CdCl2-treated mice at a time when immunoreactive HSP70 is detectable in the kidneys, but before the development of interstitial mononuclear cell infiltrates. T cells isolated from the nephritic kidneys of mice treated with CdCl2 for 13 wk are also cytotoxic to heat shocked or cadmium-treated tubular cells. These kidney-derived T cells additionally induced interstitial nephritis after passive transfer, indicating their pathogenic significance. Our studies strongly support a role for HSP-reactive T cells in CdCl2-induced interstitial nephritis and suggest that the induction of HSPs in the kidney by a multitude of "non-immune" events may initiate or facilitate inflammatory damage by HSP-reactive lymphocytes.

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Heat shock prevents simulated ischemia-induced apoptosis in renal tubular cells via a PKC-dependent mechanism

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.2001.281.1.r359 ◽

2001 ◽

Vol 281 (1) ◽

pp. R359-R364 ◽

Cited By ~ 27

Author(s):

K. K. Meldrum ◽

D. R. Meldrum ◽

S. F. Sezen ◽

J. K. Crone ◽

A. L. Burnett

Keyword(s):

Heat Stress ◽

Thermal Stress ◽

Heat Shock ◽

Ischemic Tolerance ◽

Tubular Cells ◽

Renal Tubular Cells ◽

Simulated Ischemia ◽

Renal Tubular ◽

Induced Apoptosis ◽

Dependent Mechanism

Heat shock produces cellular tolerance to a variety of adverse conditions; however, the protective effect of heat shock on renal cell ischemic injury remains unclear. Protein kinase C (PKC) has been implicated in the signaling mechanisms of acute preconditioning, yet it remains unknown whether PKC mediates heat shock-induced delayed preconditioning in renal cells. To study this, renal tubular cells (LLC-PK1) were exposed to thermal stress (43°C) for 1 h and heat shock protein (HSP) 72 induction was confirmed by Western blot analysis. Cells were subjected to simulated ischemia 24 h after thermal stress, and the effect of heat shock (delayed preconditioning) on ischemia-induced apoptosis (terminal deoxynucleotidyl transferase dUTP nick-end labeling) and B cell lymphoma 2 (Bcl2) expression (Western) was determined. Subsequently, the effect of PKC inhibition on HSP72 induction and heat stress-induced ischemic tolerance was evaluated. Thermal stress induced HSP72 production, increased Bcl2 expression, and prevented simulated ischemia-induced renal tubular cell apoptosis. PKC inhibition abolished thermal induction of HSP72 and prevented heat stress-induced ischemic tolerance. These data demonstrate that thermal stress protects renal tubular cells from simulated ischemia-induced apoptosis through a PKC-dependent mechanism.

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