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Hierarchical change in antioxidant enzyme gene expression and activity in acute cardiac rejection: role of inducible nitric oxide synthase. Mol Cell Biochem 2005 Feb;270(1-2):39-47

Date

03/29/2005

Pubmed ID

15792352

DOI

10.1007/s11010-005-3639-2

Scopus ID

2-s2.0-15944396597   14 Citations

Abstract

Reactive oxygen and nitrogen may mediate inflammation injury, but the status of the antioxidant defense system that might influence this process is unknown. In the present study, we examined the expression profile of the antioxidant enzymes, manganese superoxide dismutase (MnSOD), catalase and glutathione peroxidase (GPX) in acutely rejecting cardiac allografts and the potential role of inducible nitric oxide synthase (iNOS) in modulating antioxidant gene expression and activity. Donor hearts from Lewis (isograft) or Wistar-Furth (allograft) rats were transplanted into Lewis recipient rats. A subset of the allografts received L-N6-(1-imino-ethyl) lysine (L-NIL), a specific iNOS inhibitor, beginning the day of surgery until the day of harvesting. Catalase and glutathione peroxidase (GPX) protein levels were significantly decreased by postoperative day 4 (POD4) and postoperative day 5 (POD5), respectively, in allografts compared to isografts. While CuZn superoxide dismutase (CuZn SOD) levels were unchanged, there was a 50% decrease in MnSOD protein in allografts at postoperative day 6 (POD6). The sequential loss in antioxidant protein levels was not due to transcriptional regulation since there was no change in RNA levels for any of the genes tested. L-NIL did not alter catalase protein; however, the loss of MnSOD protein at POD6 was prevented by L-NIL. Consistent with a decrease in antioxidant protein levels, there was a sequential loss in enzyme activity for MnSOD, catalase and GPX. L-NIL however, restored MnSOD and GPX activities but not catalase activity. Treatment with CsA restored both protein and enzyme activities of GPX and MnSOD but not catalase. These results indicate that the loss in MnSOD and GPX protein and activity in allografts occurs via an iNOS-dependent mechanism whereas the decrease in catalase appears to be iNOS-independent. This suggests a differential role for iNOS in regulating post-translational modification of individual antioxidant enzymes in acute cardiac transplantation.

Author List

Nilakantan V, Zhou X, Hilton G, Roza AM, Adams MB, Johnson CP, Pieper GM

Authors

Christopher P. Johnson MD Professor in the Surgery department at Medical College of Wisconsin
Allan M. Roza MD Professor in the Surgery department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Antioxidants
Blotting, Western
Catalase
Cyclosporine
Densitometry
Down-Regulation
Enzyme Inhibitors
Gene Expression Regulation
Glutathione Peroxidase
Graft Rejection
Heart Transplantation
Immunosuppressive Agents
Inflammation
Lysine
Nitric Oxide
Nitric Oxide Synthase
Nitric Oxide Synthase Type II
Protein Processing, Post-Translational
RNA
Rats
Rats, Inbred Lew
Rats, Inbred WF
Reactive Nitrogen Species
Reactive Oxygen Species
Reverse Transcriptase Polymerase Chain Reaction
Superoxide Dismutase
Time Factors
Transcription, Genetic
jenkins-FCD Prod-478 d1509cf07a111124a2d122fd3df854cc0b993c00