IL-1RI deficiency ameliorates early experimental renal interstitial fibrosis.
BACKGROUND
IL-1beta has the potential to promote progressive renal disease by effects on macrophage recruitment and activation or by effects mediated through tubular cell transforming growth factor (TGF)-beta production, previously demonstrated in vitro.


METHODS
The in vivo roles of endogenous IL-1beta and its type I receptor (IL-1RI) in renal fibrosis were studied using wild-type C57BL/6 mice, IL-1beta(-/-) and IL-1RI(-/-) mice with unilateral ureteric obstruction.


RESULTS
After 7 days, IL-1RI(-/-) mice (IL-1alpha and IL-1beta deficient) were protected from injury and collagen accumulation. IL-1beta(-/-) mice demonstrated some histological protection, but no reduction in alpha1(1) procollagen mRNA or biochemically measured collagen accumulation. Compared with obstructed kidneys from wild-type mice, TGF-beta1 mRNA was reduced in IL-1RI(-/-) mice (with trends to reduced TGF-beta2 and TGF-beta3). Expression of a downstream TGF-beta effector, connective tissue growth factor, was decreased in IL-1RI(-/-) mice. IL-1RI(-/-) mice exhibited less tubulointerstitial apoptosis compared with wild-type mice. Macrophage infiltration and adhesion molecule mRNA expression was unchanged in IL-1beta(-/-) or IL-1RI(-/-) mice. While TNF expression was similar to wild-type mice, IFN-gamma expression was reduced in both IL-1beta(-/-) and IL-1RI(-/-) mice. IL-1RI(-/-) mice at 14 days showed a catch-up in fibrosis compared with wild-type mice.


CONCLUSIONS
IL-1/IL-1RI interactions are profibrotic in renal fibrosis. IL-1RI(-/-) mice were more protected at an early stage, associated with changes in TGF-beta and downstream mediators of fibrosis, but independent of the presence of infiltrating macrophages.
Jones
Lynelle K
LK
Department of Medicine, Centre for Inflammatory Diseases, Monash University, Monash Medical Centre, Clayton, Victoria, Australia.
O'Sullivan
Kim M
KM
Semple
Timothy
T
Kuligowski
Michael P
MP
Fukami
Kei
K
Ma
Frank Y
FY
Nikolic-Paterson
David J
DJ
Holdsworth
Stephen R
SR
Kitching
A Richard
AR
D000818:Animals; D005355:Fibrosis / Q000209:etiology; D007668:Kidney / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D053573:Receptors, Interleukin-1 Type I / Q000172:deficiency* / Q000502:physiology
D053573:Receptors, Interleukin-1 Type I