| AB STRACTIn the initiation and progression of glomerulonephritis, it has been postulated that various cytokines play crucial roles. Cytokines exert their activity on two levels:one is offending factors, which initiate and promote the magnification of inflammatory processes; the other is defense machinaery, which exert local defense. The balance between local offense factors and defense machinery determines the fate of tissue injury: progression or resolution, in glomerular research, the most interest has been on the offensive side, for example, the roles of leukocytes, platelets, complement, cytokines, eicosanoids, and oxygen radical intermediates. There has been little focus on the defensive side, which is responsible for the attenuation and resolution of disease.Interleukin(IL)- 13 is a novel anti-inflammatory cytokine, and inhibits synthesis of pro-inflammatoy cytokines, including tumor necrosis factor-cL, IL-i, IL-6, IL-8, and up-regulates IL-i receptor antagonist (IL-ira) and IL-i decoy receptor. In the previous study, we demonstrated that IL- 13 levels were significantly increased in childhood with nephrotic syndrome. However, the role of IL- 13 in the pathogenesis of glomerulonephritis is undetermined. Careful study of the expression of IL-13 in glomerulonephritis in vivo and in vitro, effect of IL-13 on pro-inflammatoy cytokines and the signal transduction involved may be helpful to explain the pathogensis of glomerular injury, and ultimately lead to novel therapeutic approaches to renal diseases.The present study consists four parts:Part I: Expression of IL-13 in glomerulonephritis in vivo and in vitroObjective:The purpose of this study was to determine the expression of antiinflammatory cytokine, interleukin-13 (IL-13) in renal tissue of human diseased kidney and the regulation of IL-13 expression in cultured mesangial cells.Methods:The IL-i 3 cDNA fragment was amplified, from PHA- and PMA5activated periPheral blood mononuclear cells (PBMC) by using RT-PCR and thencloned into pUCm-T veCtOr tO prePare IL-l3 cDNA probe. Non-radioactive in situhybridization with DIGlabeled hIL-l3 cDNA probe and true-color medical imagesystem were used to examine the expression of IL-l3 theA in tissues fromproliferative and non-proliferative glomerulonephritis and the relationship wereanalyzed betWeen the expression of IL-l3 mRNA and the degree of glomerularinjUry The IL-l3 mRNA expression and protein production by LPS, IL-l0-, andWiF-a-activated HMC were detected by semiquantitaive reverse transcription-PCR a-nd ELISA, respectively. Cytoplasmic IL-l3 production by LPS-activatedHMC was mesasured by intracytoplasmic cytokine staining with anti-IL-l3 mAband flow cytometry.ResuIts: In the normal kidney, a constitutive expression of IL-l3 mRNA wasobserved in the podocyte, cel1s of the Browma-n's capsule and distal tubularepithelial cells. In diseased glomeruli, IL-13 mRNA was strongly expressed inresident glomerular cells, including mesangial cells, endothelial cel1s, glomerularepithelial cel1s, cells of the Bowman's caPsule, and the infiltrating inflammatorycells. In MsPGN, IL-l3 expression correlated positively with the degree ofmesangial hypercellularity and extrace1lular matrix expansion. HMC stimulatedwith LPS, IL-l0, and 'I'NF-a produced IL-l3 in a dose-dependent and time-dependent manner. Anti-mF-a partia1ly decreased IL-l3 production by LPS-stimulated HMC.ConIusion: These results suggested that an autocrine andjor paracrine IL-l6 andThF-a played an important ro1e in regulation of IL-l3 expression in HMC. Renalresidents cells activated by pro-inflanunatoy mediators may cause the uPregulationof IL-l3 in glomerulonephritis and IL-l3 may be involved in tissue injury inglomeru1onephritis.Part II: Inhibitory cffect of IL-13 on innammation of mesangial celIs.Objective: In the previous study, we have demonstrated that IL-l3 was an6auocrine cytokine of mesangial cells. The present study was to investigate the role... |
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