Heat shock protein 27 in chronic allograft nephropathy: a local stress response.
BACKGROUND
Heat shock protein (HSP) 27 plays a cytoprotective role through its antioxidant, antiapoptotic, and actin-stabilizing properties during cell stress. The authors hypothesized that HSP27 is involved in chronic allograft nephropathy (CAN), a chronic state of inflammation and stress.


METHODS
The authors used the Fisher 344-to-Lewis model of CAN. Transplants were performed in 3-month-old recipient rats. HSP27 mRNA and protein levels were determined using semiquantitative polymerase chain reaction, microarray (stress-toxicity, GEArray) analyses, gene sequencing, immunoblotting, and immunohistochemical analyses at 10 days and 6 months posttransplant. P38 mitogen-activated protein kinase (MAPK), manganese (Mn) superoxide dismutase (SOD), copper-zinc (CuZn) SOD, FasL, Bax, hypoxia-inducible factor (HIF)-1alpha, and CD3 lymphocytes were studied in parallel as selective biomarkers of oxidative stress (OS), apoptosis, hypoxia, and graft-infiltrating immune cells.


RESULTS
Six months after transplantation, kidney allografts displayed histologic and functional features of CAN, including tubular atrophy, interstitial fibrosis, glomerulosclerosis, and increased proteinuria and serum creatinine levels. HSP27 mRNA and protein levels in CAN were reduced by 50% and 85%, respectively (P=0.04). Immunohistochemical analyses revealed a "shift" in HSP27 from the medulla to the cortex in allografts with CAN. Bax, phosphorylated p38-MAPK, HIF-1alpha, and MnSOD followed a parallel relocation pattern. CD3 lymphocyte density and tubular FasL expression were also greater in the cortex of allografts with CAN. Time-course analyses revealed that most of these changes were present as early as 10 days posttransplant.


CONCLUSIONS
The shift of HSP27 from the medulla to the cortex, combined with greater CD3, p38-MAPK, Bax, FasL, HIF-1alpha, and MnSOD immunoreactivity in this area of the kidney, likely represents an allograft-level response to CAN-related OS-hypoxia.
Djamali
Arjang
A
Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA.
Reese
Shannon
S
Oberley
Terry
T
Hullett
Debra
D
Becker
Bryan
B
D000818:Animals; D001483:Base Sequence; D002908:Chronic Disease; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000032:analysis* / Q000235:genetics*; D007672:Kidney Cortex / Q000166:cytology / Q000473:pathology; D007679:Kidney Medulla / Q000166:cytology / Q000473:pathology; D016030:Kidney Transplantation / Q000473:pathology*; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000032:analysis* / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014184:Transplantation, Homologous / Q000473:pathology*
D055551:HSP27 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D012333:RNA, Messenger