Nuclear factor-kappaB motif and interferon-alpha-stimulated response element co-operate in the activation of guanylate-binding protein-1 expression by inflammatory cytokines in endothelial cells.

The large GTPase GBP-1 (guanylate-binding protein-1) is a major IFN-gamma (interferon-gamma)-induced protein with potent anti-angiogenic activity in endothelial cells. An ISRE (IFN-alpha-stimulated response element) is necessary and sufficient for the induction of GBP-1 expression by IFN-gamma. Recently, we have shown that in vivo GBP-1 expression is strongly endothelial-cell-associated and is, in addition to IFN-gamma, also activated by interleukin-1beta and tumour necrosis factor-alpha, both in vitro and in vivo [Lubeseder-Martellato, Guenzi, Jörg, Töpolt, Naschberger, Kremmer, Zietz, Tschachler, Hutzler, Schwemmle et al. (2002) Am. J. Pathol. 161, 1749-1759; Guenzi, Töpolt, Cornali, Lubeseder-Martellato, Jörg, Matzen, Zietz, Kremmer, Nappi, Schwemmle et al. (2001) EMBO J. 20, 5568-5577]. In the present study, we identified a NF-kappaB (nuclear factor kappaB)-binding motif that, together with ISRE, is required for the induction of GBP-1 expression by interleukin-1beta and tumour necrosis factor-alpha. Deactivation of the NF-kappaB motif reduced the additive effects of combinations of these cytokines with IFN-gamma by more than 50%. Importantly, NF-kappaB p50 rather than p65 activated the GBP-1 promoter. The NF-kappaB motif and ISRE were detected in an almost identical spatial organization, as in the GBP-1 promoter, in the promoter regions of various inflammation-associated genes. Therefore both motifs may constitute a cooperative inflammatory cytokine response module that regulates GBP-1 expression. Our findings may open new perspectives for the use of NF-kappaB inhibitors to support angiogenesis in inflammatory diseases including ischaemia.

Angiotensin inhibition reduces glomerular damage and renal chemokine expression in MRL/lpr mice.

Beneficial effects of angiotensin II inhibition during inflammatory renal disease may involve both hemodynamic and nonhemodynamic mechanisms. To analyze whether angiotensin II inhibition has protective effects on lupus-like, autoimmune-mediated renal damage in MRL/lpr mice, four groups of mice were treated orally for 6 weeks with: 1) vehicle, 2) enalapril (3.0 mg/kg per day), 3) candesartan cilexetil (5.0 mg/kg), or 4) amlodipine (10 mg/kg) as a blood pressure control (n = 9-12/group). All antihypertensive treatments lowered blood pressure to a similar level compared with vehicle group (enalapril: 99.8 +/- 8.3 mm Hg; candesartan: 101 +/- 9 mm Hg; amlodipine: 103.8 +/- 6.7 mm Hg; vehicle: 113.5 +/- 4.6 mm Hg). Vehicle-treated mice developed a moderate glomerular injury with albuminuria (35.1 +/- 39.0 microg/mg of creatinine). Glomerular lesions consisted of immune complex deposition and mesangial expansion with increased mesangial cell proliferation. Amlodipine treatment had no significant protective effects. In contrast to vehicle- and amlodipine-treated mice, those subjected to angiotensin II blockade with enalapril or candesartan had reduced albuminuria, glomerular expansion, and mesangial proliferation. This was associated with significantly reduced renal chemokine mRNA expression compared with vehicle treatment. Our results show that inhibition of angiotensin II has protective effects on the glomerular damage of MRL/lpr mice that extend beyond hemodynamics and involve down-modulation of glomerular inflammation, reduction of mesangial cell proliferation, and decrease in chemokine expression.