Protective role of JAK/STAT signaling against renal fibrosis in mice with unilateral ureteral obstruction

Inflammation is involved in renal fibrosis, a final common pathway for kidney diseases. To clarify how JAK/STAT/SOCS system was involved in renal fibrosis, UUO was induced in BALB/c or SOCS3^+/− mice in the presence or absence of JAK inhibitor-incorporated nanoparticle (pyridine6–PGLA). UUO increased pSTAT3 and subsequently elevated SOCS3 levels in the obstructed kidneys. pSTAT3 levels were further increased in SOCS3^+/− mice. UUO-induced renal fibrosis was markedly suppressed in SOCS3^+/− mice, while it was aggravated by pre-treatment with pyridine6–PGLA. Although there were no differences in renal mRNA levels of TGF-β and collagens between wild and SOCS3^+/− mice, MMP-2 activity was enhanced in SOCS3^+/− UUO mice. Activated MMP-2 was completely suppressed by pyridine6–PGLA-pre-treatment. TNF-α one of JAK/STAT activators, increased pSTAT3 levels and subsequently induced MMP-2 activation in proximal tubular cells. These results suggest that JAK/STAT3 signaling may play a role in repair process of renal fibrosis in UUO partly via MMP-2 activation.     

丹参酮ⅡA磺酸钠对单侧输尿管梗阻病人肾间质成纤维细胞Cyclin D1蛋白表达的影响及意义

目的:研究丹参酮ⅡA磺酸钠(sodium tanshinone Ⅱ-A sulfonate,DS-201)对单侧输尿管梗阻(UUO)病人肾间质纤维化来源的成纤维细胞(hRIFs)体外增殖及细胞周期素D1(cyclin D1)蛋白表达的影响,探讨该药治疗肾间质纤维化的作用机制.方法:体外培养鉴定hRIFs;用四甲基偶氮唑(MTT)法检测对照组与不同DS-201浓度组hRIFs的增殖活性;用免疫细胞化学SABC法和图像分析技术检测对照组与不同DS-201浓度组hRIFs cyclin D1基因的表达.结果:随药物浓度的升高和作用时间的延长,抑制率逐渐升高,抑制作用逐渐增强,呈剂量依赖性和时间依赖性;用药组阳性细胞的光密度值在第3、5、7、9天显著低于对照组(P＜0.05,P＜0.01),第1天各组之间无统计学差异(P＞0.05).结论:①DS-201对UUO病人hRIFs体外增殖有显著抑制作用,可能是其治疗肾间质纤维化的机制之一;②DS-201抑制UUO病人hRIFs体外增殖可能是通过抑制细胞中cyclin D1基因表达,延长细胞周期实现的.     

Effect of Astragalus membranaceus and Angelica sinensis combined with Enalapril in rats with obstructive uropathy

ACE inhibitors (ACEi) reduce renal tubulointerstitial fibrosis but are not completely effective. Combined extract of Astragalus membranaceus and Angelica sinensis (A&A) is a traditional antifibrotic agent in China. The present investigation aimed to determine whether an ACEi (Enalapril) and A&A together have a better antifibrotic effect in unilateral ureteral obstruction (UUO) than monotherapy with either agent. Male Sprague‐Dawley rats (N = 4 per group) had either sham operation or UUO alone, with A&A (combined aqueous and ethanol extract equivalent to 2.1 g dried herbs), with Enalapril (in drinking water at 200 mg/mL) or with both treatments. Kidney and liver were collected for protein extraction or fixed for histologic stains, immunohistochemistry (IHC), microscopy. Enalapril or A&A individually were antifibrotic. Transforming growth factor‐β1, fibroblast activation, collagen deposition, macrophage accumulation and tubular cell apoptosis were all decreased. The combination of the two drugs was significantly more effective than Enalapril alone in reducing tumor necrosis factor‐α, collagen accumulation, activation of fibroblasts, and tubular cell apoptosis. In conclusion, Enalapril with A&A significantly decreased tubulointerstitial fibrosis to a greater extent than treatment with Enalapril alone. Further studies focusing on the isolation of the active constituents of A&A and the clinical application of the combination of ACEi plus A&A are warranted to determine the value of this treatment in humans. Copyright © 2009 John Wiley & Sons, Ltd.     

Expression of intronic miRNAs and their host gene Igf2 in a murine unilateral ureteral obstruction model

The objective of this study was to determine the expression of miR-483 and miR-483* and the relationship among them, their host gene (Igf2), and other cytokines in a murine model of renal fibrosis. The extent of renal fibrosis was visualized using Masson staining, and fibrosis was scored 3 days and 1 and 2 weeks after unilateral ureteral obstruction (UUO). Expression of miR-483, miR-483* and various cytokine mRNAs was detected by real-time polymerase chain reaction (PCR). Expression of miR-483 and miR-483* was significantly upregulated in the UUO model, particularly miR-483 expression was the greatest 2 weeks after surgery. Additionally, miR-483 and miR-483* expression negatively correlated with Bmp7 expression and positively correlated with Igf2, Tgfβ, Hgf, and Ctgf expression, as determined by Pearson''s correlation analysis. Hgf expression significantly increased at 1 and 2 weeks after the surgery compared to the control group. This study showed that miR-483 and miR-483* expression was upregulated in a murine UUO model. These data suggest that miR-483 and miR-483* play a role in renal fibrosis and that miR-483* may interact with miR-483 in renal fibrosis. Thus, these miRNAs may play a role in the pathogenesis of renal fibrosis and coexpression of their host gene Igf2.     

六味地黄汤对UUO大鼠肾组织Fas和FasL表达的影响

目的：探讨六味地黄汤对UUO大鼠肾组织Fas、FasL（Fas、FasL蛋白）表达的影响。方法：将清洁级SD大鼠随机分成假手术组、模型组、依那普利组、六味地黄组。模型组、依那普利组和六味地黄组进行左侧输尿管结扎;假手术组只分离左侧输尿管,不结扎。六味地黄组给予等效的六味地黄超微饮片灌胃,依那普利组每天给予等剂量的依那普利灌胃,模型组、假手术组以等体积的0.9%生理盐水灌胃,于术后7d,14d,21d每组大鼠中随机取6只处死。HE和Masson染色方法观察左肾组织形态学改变,免疫组化学检测大鼠肾组织中Fas和FasL的表达。结果：同模型组相比,术后7d,治疗组肾间质纤维化程度减轻,Fas、FasL表达下调,术后14d,21d更加明显,组间差异有统计学意义（P〈0.05）;六味地黄组同依那普利组相比,组间差异无统计学意义（P〉0.05）。结论：六味地黄汤能够减轻单侧输尿管结扎大鼠肾间质纤维化程度,其疗效可能是通过降低肾组织Fas、FasL的表达。     

Renal targeting of kinase inhibitors

Activation of proximal tubular cells by fibrotic and inflammatory mediators is an important hallmark of chronic kidney disease. We have developed a novel strategy to intervene in renal fibrosis, by means of locally delivered kinase inhibitors. Such compounds will display enhanced activity within tubular cells and reduced unwanted systemic effects. In our approach kinase inhibitors are linked to the renal carrier lysozyme using a platinum-based linker that binds drugs via a coordinative linkage. Many kinase inhibitors contain aromatic nitrogen atoms able to bind to this linker without the need of prior derivatization. The resulting drug-lysozyme conjugates are rapidly filtered in the glomerulus into the tubular lumen and subsequently reabsorbed via the endocytic pathway for clearance of low-molecular weight proteins. An important property of the formed conjugates is their in vivo stability and the sustained drug release profile within target cells. This review summarizes the state-of-the-art of drug targeting to the kidney. Furthermore, we will highlight recent results obtained with kinase inhibitor-lysozyme conjugates targeted to different kinases, i.e. the transforming growth factor (TGF)-beta-receptor kinase, p38 MAPkinase and Rho-associated kinase. Both in vitro and in vivo results demonstrated their efficient tubular uptake and beneficial therapeutic effects, superior to treatment with free kinase inhibitors. These proof-of-concept studies clearly indicate the feasibility of drug targeting for improving the renal specificity of kinase inhibitors.     

槐杞黄清膏抑制UUO大鼠肾间质纤维化的初步研究

目的:探讨槐杞黄清膏对肾间质纤维化的疗效及其作用机制.方法:Wistar大鼠随机分为5组,每组5只, 分别为假手术组、UUO(unilateral ureteral obstruction)组,1.5 g·kg^-1槐杞黄治疗组,2.25 g·kg^-1槐杞黄治疗组和3.0 g·kg^-1槐杞黄治疗组.于术后第3天开始,每天分别给予治疗组大鼠1.5 g·kg^-1, 2.25 g·kg^-1,3.0 g·kg^-1槐杞黄清膏水溶剂灌胃;于术后第14 d处死大鼠后获取肾脏组织.梗阻侧肾脏组织行HE、Masson染色,观测肾间质病理改变;免疫组化方法检测肾间质肌成纤维细胞堆积程度;Western-Blot方法检测梗阻侧肾组织α-SMA蛋白表达水平.结果:与假手术组相比,UUO模型组大鼠建模后14 d肾间质严重损伤并伴明显纤维化病变,大量肌成纤维细胞在肾间质广泛堆积.2.25 g·kg^-1,3.0 g·kg^-1槐杞黄清膏治疗UUO大鼠后,间质纤维沉积及间质肌成纤维细胞浸润明显减少.Western Blot检测结果显示2.25 g·kg^-1、3.0 g·kg^-1剂量槐杞黄清膏治疗UUO大鼠14 d时,α-SMA蛋白表达下调.结论:在肾间质纤维化早期使用2.25 g·kg^-1、3.0 g·kg^-1槐杞黄可减轻UUO大鼠肾间质肌成纤维细胞堆积从而减轻肾间质纤维化.     

Baicalin protects against renal interstitial fibrosis in mice by inhibiting the TGF-β/Smad signalling pathway

ContextBaicalin, a flavonoid extracted from radix scutellariae, possesses various pharmacological effects, including protective effects on renal interstitial fibrosis (RIF), but its possible role and mechanisms have not been fully elucidated.ObjectiveThis study explores the protective effects and mechanisms of baicalin on RIF.Materials and methodsC57BL/6 male mice were divided into six groups: sham, model, low baicalin, middle baicalin, high baicalin and positive drug groups. The unilateral ureteral obstruction (UUO) model of RIF was constructed and treated with baicalin doses (10, 20 and 40 mg/kg) and a positive control drug (valsartan, 8 mg/kg). H&E staining was used to observe the pathological changes in renal tissues, Masson staining was performed to evaluate collagen deposition in renal tissues, and immunohistochemical examination was adopted to determine α-SMA and extracellular matrix (ECM) expression. Primary mouse fibroblasts were isolated, extracted and treated with baicalin and/or TGF-β. qRT-PCR and enzyme-linked immunosorbent assay (ELISA) were applied to detect the inflammatory responses. Moreover, ECM and TGF-β/Smad expression levels were evaluated by western blot assay.ResultsBaicalin ameliorated RIF in UUO mice by inhibiting fibrosis and inflammatory responses. The TGF-β/Smad pathway was significantly suppressed in the UUO mouse model. Additionally, baicalin significantly inhibited ECM expression and inflammatory factors in fibroblasts treated with TGF-β. TGF-β/Smad pathway activation was significantly decreased in fibroblasts.Discussion and conclusionsThese findings support the use of baicalin as a potential therapeutic option for the treatment of RIF by possibly inhibiting the TGF-β/Smad signalling pathway.     

Enhanced mobilization of bone marrow cells does not ameliorate renal fibrosis.

BACKGROUND: The plasticity of bone marrow-derived stem cells, also comprising haematopoietic stem cells, has been shown to extend to renal epithelial lineages. Yet, the low rate of their contribution to the injured kidney has led to questions regarding their significance in tissue repair after acute injury. We describe here the effect of stem cell mobilization therapy on the progression of renal fibrosis in a mouse model of chronic obstructive nephropathy. METHODS: Mice were subjected to unilateral ureter obstruction (UUO) and treated with stem cell factor (SCF) and granulocyte-colony stimulating factor (G-CSF) or saline. Circulating cells were analysed by flow cytometry; labelled bone marrow c-KIT(HIGH) cells were injected into animals subjected to UUO. Granulocytes, macrophages, cellular proliferation or apoptosis and myofibroblasts were detected by immunostaining. Collagen deposition was determined by measuring renal hydroxyproline contents. Cytokine levels were measured by ELISA. RESULTS: SCF/G-CSF treatment of mice induced significant haematopoietic stem and progenitor cell mobilization from the bone marrow. Although these cells are able to migrate to the obstructed kidney, they did not influence renal damage, fibrosis and inflammatory cell influx. CONCLUSIONS: Although SCF/G-CSF treatment significantly enhanced the availability of haematopoietic stem cells to the obstructed kidney, the progression of renal fibrosis could not be delayed or halted. Our results indicate that effective stem cell mobilization does not alter renal fibrosis.