Effect of calcineurin inhibitors on extracellular matrix turnover in isolated human glomeruli.
ABSTRACT Although chronic cyclosporine toxicity is mainly characterized by tubular atrophy and interstitial fibrosis, glomerular injury with expansion of mesangial matrix and sclerosis is not uncommon. Tacrolimus is a newer calcineurin inhibitor that has been used in renal transplant recipients as primary or rescue therapy. Clinical trials suggest an improved long-term graft survival among patients treated with tacrolimus. Recently we have shown that tacrolimus and cyclosporine have similar effects on extracellular matrix turnover in cultured cells. The present study was performed to investigate the effects of the calcineurin inhibitors on whole glomeruli extracellular matrix turnover.
Human glomeruli isolated from kidney biopsies just before transplantation were incubated with culture media containing either cyclosporine (200 ng/mL) or tacrolimus (10 ng/mL) for 24 hours. Glomeruli incubated only with culture medium were used as control.
The expressions of (alpha2)IV collagen, metalloprotease 9 (MMP9), tissue inhibitors of metalloproteases 2 (TIMP-2), and TGFbeta were evaluated by in situ reverse transcription and polymerase chain reactions (RT-PCR). beta-actin was used as a control gene. Cyclosporine (but not tacrolimus) increased the expression of (alpha2)IV collagen and TIMP2 in isolated glomeruli. TGF-beta was markedly increased by cyclosporine. MMP9 expression was not affected by the calcineurin inhibitors. By light microscopy kidney biopsies did not show pathologic changes.
Cyclosporine treatment modulates extracellular matrix turnover in isolated human glomeruli, inducing an imbalance between synthesis and degradation. This effect, not observed in tacrolimus-treated human glomeruli, may induce the extracellular matrix deposition and sclerosis characteristic of chronic cyclosporine toxicity.
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ABSTRACT: Exploring the expression of Toll-like receptor (TLR) in cyclosporine (CsA)-induced renal injury in humans, we evaluated the expression of TLR4 in both biopsied renal tissue and cultured tubular cells. Immunohistochemical stains for TLR4, heat shock protein (HSP) 47, and HSP70 were performed in both pre- and post-treatment biopsies obtained from 18 patients of minimal change nephrotic syndrome or IgA nephropathy treated with CsA, and the percentage of positive tubules was compared in each case. For in vitro experiments, HK-2 cells were treated with CsA (2, 5, and 10 microg/ml) for 24, 48, and 72 h. TLR4 mRNA and protein were measured using real-time RT-PCR and Western blot. In addition, hypoxic effect was added by GasPak System. The tubular expressions of TLR4 (2.2 +/- 1.2% vs 4.4 +/- 2.0%, p < 0.001) and HSP70 (2.6 +/- 2.8% vs 6.1 +/- 4.2%, p = 0.002) were increased after CsA treatment. TLR4 mRNA and protein expression were also increased in a dose-dependent manner. Hypoxia enormously increased TLR4 expression. In summary, CsA increased tubular expression of TLR4 and its ligand HSP70. As hypoxia was shown to be a strong stimulus for TLR4 expression, it can be said that TLR4 is influenced by both direct toxicity and impediment of renal microcirculation in human CsA nephrotoxicity.Apmis 08/2009; 117(8):583-91. · 1.92 Impact Factor
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ABSTRACT: The MMPs and their inhibitors [tissue inhibitor of MMPs (TIMPs) ] form the mainstay of extracellular matrix homeostasis. They are expressed in response to numerous stimuli including cytokines and GPCR activation. This review highlights the importance of adrenoceptors and phosphoprotein phosphatases (PPP) in regulating MMPs in the cardiovascular system, which may help explain some of the beneficial effects of targeting the adrenoceptor system in tissue remodelling and will establish emerging crosstalk between these three systems. Although - and β-adrenoceptor activation increases MMP but decreases TIMP expression, MMPs are implicated in the growth stimulatory effects of adrenoceptor activation through transactivation of epidermal growth factor receptor. Furthermore, they have recently been found to catalyse the proteolysis of β-adrenoceptors and modulate vascular tone. While the mechanisms underpinning these effects are not well defined, reversible protein phosphorylation by kinases and phosphatases may be key. In particular, PPP (Ser/Thr phosphatases) are not only critical in resensitization and internalization of adrenoceptors but also modulate MMP expression. The interrelationship is complex as isoprenaline (ISO) inhibits okadaic acid [phosphoprotein phosphatase type 1/phosphoprotein phosphatase type 2A (PP2A) inhibitor]-mediated MMP expression. While this may be simply due to its ability to transiently increase PP2A activity, there is evidence for MMP-9 that ISO prevents okadaic acid-mediated expression of MMP-9 through a β-arrestin, NF-κB-dependent pathway, which is abolished by knock-down of PP2A. It is essential that crosstalk between MMPs, adrenoceptors and PPP are investigated further as it will provide important insight into how adrenoceptors modulate cardiovascular remodelling, and may identify new targets for pharmacological manipulation of the MMP system.British Journal of Pharmacology 05/2012; 166(4):1225 - 1243. · 5.07 Impact Factor
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ABSTRACT: Background: Regulatory T-cells (Treg) are natural suppressors of autoimmunity. Previous studies indicate that immunosuppressive drugs, especially calcineurin-inhibitors, may interfere with Treg homeostasis. Inflammatory bowel disease (IBD) can relapse or develop de novo after liver transplantation. IBD is associated with a relative deficiency of Treg. The aim of this study was to determine the effect of long-term immunosuppression on the presence of Treg in the noninflamed colonic mucosa of liver transplant recipients.Methods: Colonic biopsies of normal mucosa of 36 liver transplant recipients on different types of immunosuppression and 11 controls were studied. Treg marker Foxp3 and Treg products transforming growth factor-β (TGF-β) and interleukin-10 (IL-10) were studied by quantitative polymerase chain reaction (Q-PCR) and immunohistochemistry. TGF-β-induced Smad-protein 3 and 7 were studied by Q-PCR.Results: No significant differences between controls and patients were observed in IL-10, TGF-β, and Smad expression. Mucosal Foxp3 mRNA levels and Foxp3+CD3+ cells were significantly reduced in transplant recipients using prednisone/azathioprine/tacrolimus compared with controls but no direct relationship between Foxp3 expression and 1 specific drug was detected.Conclusions: These results challenge the hypothesis that calcineurin-induced reduction of Treg or TGF-β expression predisposes nontransplanted tissue to inflammation, but indicate that combined immunosuppression hampers Treg development in the intestine.(Inflamm Bowel Dis 2007)Inflammatory Bowel Diseases 05/2007; 13(6):703 - 709. · 5.12 Impact Factor