MCP-1 is up-regulated in unstressed and stressed HO-1 knockout mice: Pathophysiologic correlates

  • Siobhan T. Pittock
  • , Suzanne M. Norby
  • , Joseph P. Grande
  • , Anthony J. Croatt
  • , Gary D. Bren
  • , Andrew D. Badley
  • , Noel M. Caplice
  • , Matthew D. Griffin
  • , Karl A. Nath

Research output: Contribution to journalArticlepeer-review

Abstract

Background. Up-regulation of heme oxygenase-1 (HO-1) occurs in, and often confers protection to, the injured kidney. Up-regulation of monocyte chemoattractant protein-1 (MCP-1) promotes not only acute and chronic nephritides but also acute ischemic and nephrotoxic injury. The present study was stimulated by the hypothesis that expression of MCP-1 is suppressed by HO-1, and analyzed the effect of HO-1 on the expression of MCP-1 in stressed and unstressed conditions. Methods. Expression of MCP-1 and pathophysiologic correlates were examined in HO-1 knockout (HO-1-/-) and wild-type (HO-1+/+) mice in the unstressed state in young and aged mice, and following nephrotoxic and ischemic insults. Results. In unstressed HO-1-/- mice, plasma levels of MCP-1 protein were elevated, and MCP-1 mRNA expression was increased in circulating leukocytes and in the kidney. Such early and heightened up-regulation of MCP-1 was eventually accompanied by phenotypic changes in the aged kidney consistent with MCP-1, namely, proliferative changes in glomeruli, tubulointerstitial disease, and up-regulation of transforming growth factor-β1 (TGF-β1) and collagens I, III, and IV. In response to a nephrotoxic insult such as hemoglobin, MCP-1 mRNA was up-regulated in a markedly sustained manner in HO-1-/- mice. In response to a duration of ischemia that exerted little effect in HO-1+/+ mice, HO-1-/- mice exhibited higher expression of MCP-1 mRNA, enhanced activation of nuclear factor-κB (NF-κB) (the transcription factor that regulates MCP-1), markedly greater functional and structural renal injury, increased caspase-3 expression, and increased mortality. Conclusion. In the absence of HO-1, expression of MCP-1 is significantly and consistently enhanced in unstressed and stressed conditions. We speculate that the protective effects of HO-1 in injured tissue may involve, at least in part, the capacity of HO-1 to restrain up-regulation of MCP-1.

Original languageEnglish
Pages (from-to)611-622
Number of pages12
JournalKidney International
Volume68
Issue number2
DOIs
Publication statusPublished - Aug 2005
Externally publishedYes

Keywords

  • Cytoprotection
  • Heme oxygenase-1
  • Ischemia
  • Kidney
  • Monocyte chemoattractant protein-1

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