Interleukin-10: Is it good or bad for the kidney?

Production of the novel mesangial autocrine growth factors GDNF and IL-10 is regulated by the immunomodulator AS101

Mesangial cell (MC) proliferation is essential for the pathogenesis and progression of various glomerular diseases. This study shows that glial cell line-derived neurotrophic factor (GDNF) and IL-10 are mesangial autocrine growth factors that play a pivotal role in rat MC proliferation in vitro. Downstream targets of GDNF signaling and their role in MC hyperplasia are identified. The phosphatidylinositol 3-kinase (PI3K) pathway and its downstream target NF-kappaB were found to mediate GDNF-induced MC mitogenesis. This pathway also mediates GDNF-induced decrease in the cyclin-dependent kinase inhibitor p27(kip1) expression, resulting in the increased formation of cyclin D1/cdk4 and cyclin E/cdk2 complexes, followed by hyperphosphorylation of retinoblastoma, a key event for G1 to S phase progression. IL-10 appears to be a more potent MC growth factor that negatively regulates GDNF expression. Indeed, its inhibition by the nontoxic tellurium anti-IL-10 compound, ammonium trichloro(dioxoethylene-o,o') tellurate (AS101), extensively decreased MC clonogenicity despite GDNF upregulation. Identification of the mesangial GDNF and IL-10 pathways as critical mediators of mesangial cell proliferation may provide another target for therapeutic intervention in certain glomerular diseases. In vivo animal studies using AS101, currently undergoing phase II clinical trials on cancer patients, are warranted to determine its potential in the management of glomerular diseases associated with mesangial cell proliferation.

Interleukin-10 inhibits experimental mesangial proliferative glomerulonephritis

Conflicting reports exist regarding the effects of interleukin-10 (IL-10) on mesangial cells. There have been reports of both proliferative and antiproliferative effects, and both proinflammatory and anti-inflammatory effects of IL-10 on mesangial cells. However, the potential for IL-10 to affect glomerulonephritis characterized by mesangial proliferation is not known. To test the hypothesis that IL-10 would limit experimental mesangial proliferative glomerulonephritis, IL-10 was administered to rats in which mesangial proliferative glomerulonephritis was induced by administration of anti-Thy 1 antibody. Compared to control treated rats, IL-10 treated rats showed less proliferation, with fewer cells in glomeruli. Glomerular cellular proliferation was reduced, assessed by the numbers of cells within glomeruli expressing either proliferating cell nuclear antigen (PCNA) or bromodeoxyuridine. Glomerular macrophage influx (but not the proportion of glomerular macrophages that were PCNA positive) was reduced by IL-10 administration. There was no significant reduction in glomerular alpha-smooth muscle actin staining. IL-10 treatment resulted in reduced renal IL-1beta mRNA expression and reduced glomerular ICAM-1 expression, but renal expression of MCP-1 and osteopontin mRNA was unaltered. This study demonstrates that in experimental mesangial proliferative glomerulonephritis IL-10 diminishes inflammatory cell recruitment and mesangial cell proliferation. The effects of IL-10 in inhibiting mesangial cell proliferation are likely to be due to a combination of direct effects of IL-10 on mesangial cells and effects mediated by macrophages.

Endogenous interleukin-10 regulates Th1 responses that induce crescentic glomerulonephritis

BACKGROUND

Interleukin (IL)-10 plays a pivotal role in regulating the Th1/Th2 predominance of immune responses. Exogenously administered IL-10 suppresses nephritogenic Th1 responses, inhibits macrophage function, and attenuates crescentic glomerulonephritis (GN). To determine the role of endogenous IL-10, the development of the nephritogenic immune response and crescentic GN was compared in IL-10-deficient (IL-10-/-) and normal (IL-10+/+) C57BL/6 mice.

METHODS

GN was initiated in sensitized mice by the intravenous administration of sheep antimouse glomerular basement membrane globulin. Renal injury was evaluated 21 days later.

RESULTS

Following the administration of anti-glomerular basement membrane globulin, normal (IL-10+/+) C57BL/6 mice developed proliferative GN with occasional crescents, glomerular CD4+ T-cell and macrophage accumulation, and fibrin deposition. Using an identical induction protocol, IL-10-/-mice developed more severe GN. Crescent formation (IL-10-/-, 23 +/- 2% of glomeruli; IL-10+/+, 5 +/- 2%), glomerular CD4+ T cells [IL-10-/-, 1. 0 +/- 0.2 cells per glomerular cross-section (c/gcs); IL-10 +/+, 0.3 +/- 0.05 c/gcs], glomerular macrophages (IL-10-/-, 4.8 +/- 0.3 c/gcs; IL-10 +/+, 1.7 +/- 0.2 c/gcs), fibrin deposition [fibrin score (range 0 to 3+); IL-10-/-, 1.10 +/- 0.04; IL-10+/+, 0.6 +/- 0. 07], and serum creatinine (IL-10-/-, 30 +/- 2 micromol/L; IL-10 +/+, 23 +/- 1 micromol/L) were all significantly increased in IL-10-/- mice (P < 0.05). Circulating antibody (IL-10-/-, 1.05 +/- 0.16 OD units; IL-10+/+, 0.63 +/- 0.08 OD units) and cutaneous delayed-type hypersensitivity (skin swelling; IL-10-/-, 0.21 +/- 0.03 mm; IL-10+/+, 0.12 +/- 0.02 mm) to the nephritogenic antigen (sheep globulin) were also increased (both P < 0.05). Interferon-gamma production by cultured splenocytes was increased (IL-10-/- 7.9 +/- 2. 5 ng/4 x 106 cells, IL-10+/+ 0.28 +/- 0.09 ng/4 x 106 cells, P < 0. 05), but IL-4 production was unchanged.

CONCLUSIONS

Endogenous IL-10 counter-regulates nephritogenic Th1 responses and attenuates crescentic GN.