High glucose decreases matrix metalloproteinase-2 activity in rat mesangial cells via transforming growth factor-beta1.

Diabetic nephropathy is characterized by accumulation of mesangial matrix. Glucose-induced inhibition of matrix-degrading enzymes such as collagenases is believed to contribute to matrix accumulation. We have previously demonstrated that 72 kDa type IV collagenase activity is decreased in the rat mesangial cells cultured in high glucose media [Diabetes 1995;44:929-935]. The present studies were designed to investigate if the cytokine transforming growth factor-beta1 (TGF-beta1) mediates this effect of glucose. Type IV collagenases degrade type IV collagen as well as gelatin (denatured collagen) and are thus also called gelatinases. They belong to the family of matrix metalloproteinases (MMPs); MMP activity is controlled by tissue inhibitors of metalloproteinases (TIMPs). The activity of 72 kDa type IV collagenase, also known as matrix metalloproteinase-2 (MMP-2), was assessed using three methods: (1) fluoresceinated gelatin degradation assay to detect free enzyme activity (activity which is present in excess of TIMP-inhibited activity); (2) zymography to measure total (free + TIMP-bound) enzyme activity; (3) ELISA using specific antibodies to measure MMP-2 levels. TGF-beta1 and TIMP-2 levels were also determined by ELISA. Incubation of primary cultures of rat mesangial cells for 5 days in 30 vs. 5 mM glucose resulted in a 3-fold increase in production of total TGF-beta1, a significant decrease in MMP-2 activity and immunoreactive MMP-2 levels, and an increase in TIMP-2 levels. Addition of exogenous TGF-beta1 to mesangial cells incubated in 5 mM glucose replicated the high glucose effect by producing a significant decrease in MMP-2 levels with a concurrent increase in TIMP-2 levels. Furthermore, glucose-induced inhibition of MMP-2 activity was completely blocked by neutralization of TGF-beta1 with anti-TGF-beta1 antibody. We conclude that the decrease in MMP-2 activity induced by glucose loading is mediated via TGF-beta1.     

megsin基因转染对高糖环境中肾小球系膜细胞增殖和基质金属蛋白酶2及其抑制因子表达的影响

目的 观察megsin基因转染对高糖环境中肾小球系膜细胞基质金属蛋白酶2（MMP-2）和组织金属蛋白酶抑制因子2（TIMP-2）的表达及Ⅳ型胶原水平的影响,探讨megsin与系膜细胞增殖和细胞外基质代谢的关系。 方法 高糖环境中培养小鼠肾小球系膜细胞,分别于培养12、24、48 h末,应用MTT法检测细胞增殖程度;Western印迹法检测系膜细胞megsin、MMP-2、TIMP-2蛋白表达水平;放免法检测细胞培养上清Ⅳ型胶原浓度。 结果 高糖环境中肾小球系膜细胞megsin、TIMP-2表达上调,MMP-2表达下调,细胞增殖明显,细胞上清液中Ⅳ型胶原浓度升高。megsin基因转染后上述变化趋势更加显著。 结论 megsin可诱导系膜细胞增殖,并通过上调TIMP-2、下调MMP-2抑制细胞外基质降解,是加速肾小球硬化的可能机制之一。     

肝门胆管癌基质金属蛋白酶MMP-2及其组织抑制因子TIMP-2表达及意义的研究

目的：探讨基质金属蛋白酶MMP－2及其组织抑制因子TIMP－2在肝门胆管癌的表达及其与肝门胆管癌浸润、转移及预后间的关系。方法：采用免疫组化S－P法对78例肝门胆管癌的MMP－2及其组织抑制因子TIMP－2的表达进行了检测。对MMP－2及TIMP－2的表达与肝门胆管癌的组织分化程度、浸润转移及预后之间的关系进行分析。结果：MMP－2和TIMP－2表达阳性率分别为72％和76％。MMP－2的阳性表达率有淋巴结浸润的肝门胆管癌高于无淋巴结浸润的肝门胆管癌，低分化的肝门胆管癌高于高分化的肝门胆管癌。TIMP－2阳性表达率与以上相反。MMP－2表达与肝门胆管癌术后生存期呈负相关（γ=-0.713,P＜0．01），TIMP－2表达与肝门胆管癌术后生存期呈正相关（γ=0.652,P＜0．01）。MMP－2与TIMP－2具有负相关关系，（γ=-0.708,P＜0．01）。结论：MMP－2与TIMP－2是反映肝门胆管癌浸润、转移及预后的指标。     

Platelet-derived growth factor stimulates matrix metalloproteinase-2 secretion in cultured human mesangial cells

Background. Platelet-derived growth factor (PDGF) is an important mediator of mesangial proliferative glomerulonephritis. Little is known about the role of PDGF in the regulation of intraglomerular extracellular matrix turnover. Method. Effects of PDGF on the secretion of matrix metalloproteinase-2 (MMP-2), tissue inhibitor of MMP-2 (TIMP-2), and type IV collagen by cultured human mesangial cells (HMCs) were examined in the present study. Secretion of MMP-2, TIMP-2, and type IV collagen by HMCs was quantified with an enzyme immunoassay. Collagenase activity of HMCs was evaluated by gelatin zymography. Results. Recombinant human PDGF (10–20 ng/ml) stimulated MMP-2 secretion by HMCs in a dose-dependent fashion. PDGF (20 ng/ml) increased TIMP-2 secretion by HMCs to a lesser extent. Enhanced activity of 72-kDa collagenase derived from HMCs incubated with PDGF was demonstrated by zymography. Although PDGF alone did not affect type IV collagen secretion by HMCs, PDGF increased type IV collagen secretion in the presence of TIMP. Conclusions. PDGF may contribute to intraglomerular matrix turnover by up-regulating secretion and activation of MMP-2 by HMCs. Received: January 24, 2001 / Accepted: September 13, 2002 Correspondence to:H. Osawa     

Effect of glucose and heparin on mesangial alpha 1(IV)COLL and MMP- 2/TIMP-2 mRNA expression

Mesangial cells are responsible for the synthesis of mesangial matrix as well as its degradation, which is mediated by a number of proteolytic activities, including metalloproteinases (MMPs). Imbalanced matrix protein metabolism may be responsible for mesangial expansion and glomerulosclerosis in diabetic nephropathy. Heparin prevents this complication. In human and murine mesangial cell cultures, RT-PCR was able to detect mRNA expression for a number of molecules involved in the mesangial extracellular matrix turnover: type IV collagen [alpha 1(IV)COLL], MMP-1, MMP-2, MMP-3, MMP-9 and MMP-10, and the tissue inhibitors TIMP-1 and TIMP-2. The expression of mRNA for alpha 1(IV)COLL and MMP-2/TIMP-2 balance was studied in human cells in the presence of high glucose and heparin. mRNAs for all the studied molecules were expressed at different levels. Interestingly, a shift in the balance of alpha 1(IV)COLL, MMP-2 and TIMP-2 was observed in high glucose, which was partially reversed by heparin supplementation. The new equilibrium was mostly due to the down-regulation of type IV collagen expression, rather than further reduction of potential proteolysis. Our data, while extending the list of potential mediators of mesangial matrix catabolism, highlight a molecular mechanism by which the pathogenesis of diabetic nephropathy may be sustained, and at the same time suggest that heparin may have the potential to correct this abnormality.      

Evidence for a role of transforming growth factor (TGF)-beta1 in the induction of postglomerular albuminuria in diabetic nephropathy: amelioration by soluble TGF-beta type II receptor

Transforming growth factor-beta (TGF-beta) has previously been implicated in the progression of diabetic nephropathy, including the onset of fibrosis and albuminuria. Here we report for the first time the use of a high-affinity TGF-beta1 binding molecule, the soluble human TGF-beta type II receptor (sTbetaRII.Fc), in the treatment of diabetic nephropathy in 12-week streptozotocin-induced diabetic Sprague-Dawley rats. In vitro studies using immortalized rat proximal tubule cells revealed that 50 pmol/l TGF-beta1 disrupted albumin uptake (P < 0.001 vs. control), an inhibition significantly reversed by the use of the sTbetaRII.Fc (1,200 pmol/l). In vivo studies demonstrated that treatment with sTbetaRII.Fc reduced urinary albumin excretion by 36% at 4 weeks, 59% at 8 weeks (P < 0.001), and 45% at 12 weeks (P < 0.01 for diabetic vs. treated). This was correlated with an increase in megalin expression (P < 0.05 for diabetic vs. treated) and a reduction in collagen IV expression following sTbetaRII.Fc treatment (P < 0.001 for diabetic vs. treated). These changes occurred independently of changes in blood glucose levels. This study demonstrates that the sTbetaRII.Fc is a potential new agent for the treatment of fibrosis and albuminuria in diabetic nephropathy and may reduce albuminuria by reducing TGF-beta1-induced disruptions of renal proximal tubule cell uptake of albumin.     

Reversibility of glucose-induced changes in mesangial cell extracellular matrix depends on the genetic background.

Adequate glycemic control protects most patients with diabetes from nephropathy, but a substantial fraction of patients develop progressive disease despite lowering glycemia. We isolated mesangial cells (MC) from the glomeruli of mouse strains that model these two outcomes in patients with diabetes, namely those that have the propensity (ROP) or resistance (B6) to develop progressive diabetic nephropathy. We determined the nature and reversibility of changes in selected extracellular matrix-related molecules after chronic exposure to elevated glucose concentration. MC were exposed to 25 mmol/l glucose for 5 weeks followed by 6 mmol/l glucose and 19 mmol/l mannitol for an additional 5 weeks. Matrix metalloproteinase-2 (MMP-2) and transforming growth factor-beta(1) (TGF-beta(1)) levels increased in B6 MC exposed to 25 mmol/l glucose but returned to baseline levels when the glucose concentration was reduced to 6 mmol/l. MMP-2 and TGF-beta(1) were higher in ROP MC at baseline and increased in response to 25 mmol/l glucose, but remained elevated when glucose concentration was reduced. Type I collagen expression and accumulation increased in a reversible manner in B6 MC exposed to 25 mmol/l glucose. However, type I collagen expression was higher in ROP MC at baseline and remained unaffected by changes in glucose concentration. Thus, 25 mmol/l glucose induced reversible changes in MMP-2, TGF-beta(1), and type I collagen in MC of sclerosis-resistant mice but not in MC from sclerosis-prone mice. Therefore, progressive diabetic nephropathy may be secondary to stable alterations in the phenotype of MC as a result of the interplay between the genetic background and elevated glucose concentrations.     

Minocycline with Aspirin: An Approach to Attenuate Diabetic Nephropathy in Rats

Degradation of extracellular matrix (ECM) by enhanced production of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in diabetes leads to nephropathy. Cyclooxygenases (COX) further increase levels of these MMPs. The objective of present study was to inhibit MMP-2 and MMP-9 by combination of minocycline and aspirin to treat diabetic nephropathy. Diabetes was induced in male Wistar rats by streptozotocin (STZ, 55 mg/kg i.p.). Four weeks after diabetes induction, the rats were treated with minocycline (50 mg/kg, p.o.), aspirin (50 mg/kg, p.o.), or minocycline (50 mg/kg, p.o.) plus aspirin (50 mg/kg, p.o.) for a period of 4 weeks. At the end of eighth week fluid input, urine output, and renal function tests were carried out for diagnosis of diabetic nephropathy. Renal hypertrophy was measured and histopathology was done to evaluate renal damage. Diabetes produced significant loss of body weight, polyuria, polydipsia, hyperglycemia, and increase in blood pressure. Serum creatinine, urea, and blood urea nitrogen levels were found to be increased significantly in the STZ group diabetic rats. Treatment with combination of minocycline and aspirin significantly prevented the rise in creatinine, urea, and blood urea nitrogen levels and increased creatinine clearance. Image analysis of kidneys revealed that collagen level was significantly decreased in combined treated group when compared with control. Results of present study suggest that MMP-2 and MMP-9 inhibition in presence of COX inhibitor prevents the development of experimental diabetic nephropathy in rats and can be a potential approach for the treatment.     

膀胱癌中MMP-2、TIMP-2的表达及其与浅表性肿瘤复发的关系

目的：研究基质金属蛋白酶－2（MMP－2）和金属蛋白酶组织抑制因子－2（TIMP－2）在膀胱癌中的表达以及它们与肿瘤临床病理因素和复发的关系。方法：用免疫组织化学SP法检测46例膀胱移行细胞癌标本中MMP－2、TIMP－2的表达，并将它们与肿瘤临床和病理参数相比较。结果：在46例膀胱癌中，MMP－2、TIMP－2的阳性率分别为47.8%和58.7%，TIMP－2在间质中的表达率为47.8%。MMP－2表达率随着肿瘤理分级、临床分期的升高而增加，而TIMP－2表达率则呈下降趋势，但在浅表性膀胱癌（Ta-T1）中，TIMP－2的表达与MMP－2相似，随着肿瘤分期分级的升高而增加，TIMP－2间质表达阳性组中浅表性膀胱癌的2年复发率显著高于表达阴性组。结论：MMP－2和TIMP－2的相互作用对于膀胱癌的侵袭发展发挥了重要作用。TIMP－2在间质中表达可作为判断浅表性膀胱癌复发的预后指标。     

Combined effects of moderately elevated blood glucose and locally produced TGF-beta1 on glomerular morphology and renal collagen production.

BACKGROUND: There is a correlation between renal graft rejection and blood glucose (BG) levels. Furthermore, diabetic patients may develop non-diabetic renal diseases, which in some circumstances progress rapidly. Since transforming growth factor-beta1 (TGF-beta) levels are elevated in many renal diseases, the accelerated progression may be due to interactions between glucose and locally produced TGF-beta1. Therefore, we investigated the effect of mild hyperglycaemia on glomerular morphology and collagen production in TGF-beta1 transgenic mice. METHODS: To achieve BG concentrations of approximately 15 mmol/l in TGF-beta1 transgenic and non-transgenic mice, we used multiple streptozotocin (STZ) injections, and after 8 weeks, we measured the changes in glomerular morphology and total collagen content. We also analysed extracellular matrix (ECM) and protease mRNA levels using real-time polymerase chain reaction (PCR) and phosphorylated extracellular signal-regulated kinase 1/2 (pERK) expression by immunohistochemistry. RESULTS: Mild hyperglycaemia alone had no effect on glomerular structure or ECM deposition. Over-expression of TGF-beta1 increased basement membrane thickness (BMT) and the mesangial volume fraction. Furthermore, it augmented ECM, Matrix metalloproteinase-2 (MMP), MMP-9, plasminogen activator inhibitor-1 (PAI) and tissue inhibitor of metalloproteinase-1 (TIMP) gene expression and pERK1/2 immunostaining. Elevated BG in combination with TGF-beta1 resulted in enlargement of glomerular volume, total mesangial volume and renal collagen content. Moreover, high BG exaggerated TGF-beta1-induced changes in the BMT, MMP-2 and TIMP-1 expression and pERK1/2 staining. CONCLUSION: Even moderate elevations in BG accelerate the progression of those kidney diseases in which TGF-beta1 is involved. This emphasizes the importance of strict BG control in renal transplant patients and diabetic patients with renal malfunctions unrelated to diabetes.     

Increase of matrix metalloproteinase-2 in dialysate of rat sclerosing encapsulating peritonitis model

SUMMARY: Sclerosing peritonitis (SP) and sclerosing encapsulating peritonitis (SEP) are serious complications of continuous ambulatory peritoneal dialysis (CAPD). the mortality rate of SP/SEP is extremely high. It is important to clarify the mechanism of progression of SP/SEP, and to prevent this complication. We prepared an animal model of SEP by intraperitoneal administration of chlorhexidine gluconate (CHX) using male Sprague-Dawley rats. Dialysate drained from these animals was analysed by gelatin zymography. In this animal model of SEP, fibrous peritoneal thickening accompanied by cellular infiltration and peritoneal adhesion, were observed. Four of six rats presented with a so-called abdominal cocoon. an increase of peritoneal absorption of glucose was also confirmed. Zymographic analysis revealed that the matrix metalloproteinase-2 (MMP-2) level was high in the dialysate from the animal model, although MMP-9 was hardly detected. From these results, the MMP-2 level in drained dialysate was considered to increase in SP/SEP. Matrix metalloproteinase-2 might be associated with the progression of SP/SEP.     

Serum matrix metalloproteinases MMP-2 and MMP-9 and metalloproteinase tissue inhibitors TIMP-1 and TIMP-2 in diabetic nephropathy

BACKGROUND: The regulation of mesangial extracellular matrix (ECM) turnover engages a number of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). High glucose concentration affects ECM degradation and the activities of MMPs and TIMPs. ECM accumulation is involved in the pathogenesis of diabetic nephropathy. METHODS: Serum MMP-9, MMP-2, TIMP-2 and TIMP-1 were measured with ELISA in patients with either chronic renal failure (CRF, n=20), type 2 diabetes mellitus (DM2, n=16) or diabetic nephropathy (DM2+CRF, n=14), and healthy controls (n=20). RESULTS: Diabetic nephropathy was related with profound decrease of serum TIMP-2 (122.2 +/- 47.2 vs. 263.0 +/- 89.2 ng/mL), TIMP-1 (242.5 +/- 96.9 vs. 347.4 +/- 87.2 ng/mL) and MMP-2 (385.4 +/- 42.6 vs. 517.2 +/- 75.4 ng/mL) (p<0.001). Both TIMP-1 and TIMP-2 were reduced in diabetic nephropathy in comparison with either diabetes alone (p<0.01 and p<0.001; respectively) or CRF alone (p<0.001 for both). An approximately 2-fold increase of MMP-9/TIMP-1 and MMP-2/TIMP-2 ratio was found in diabetic nephropathy when compared with diabetes with normal renal function (p<0.01). Further, in DM2 patients, TIMP-2 was decreased when compared with CRF alone (219.2 +/- 71.8 vs. 296.8 +/- 58.4 ng/mL). MMP-2 was lowered in both groups of DM2 and CRF patients (413.8 +/- 59.0 ng/mL and 409.7 +/- 93.1 ng/mL, vs. normal control value of 517.2 +/- 75.4 ng/mL; p<0.001). CONCLUSIONS: These data indicate that circulating TIMP-1, TIMP-2 and MMP-2 are decreased in patients with diabetic nephropathy when compared with either CRF or diabetes.     

Activation of matrix metalloproteinase-2 causes peritoneal injury during peritoneal dialysis in rats.

BACKGROUND: Sclerosing peritonitis (SP) and encapsulating peritoneal sclerosis (EPS) are serious complications of continuous ambulatory peritoneal dialysis. Although we have shown previously that matrix metalloproteinase-2 (MMP-2) is increased in peritoneal injury leading to SP/EPS, most of the MMP-2 in the dialysate drained from the peritoneal cavity was the latent form that was lacking activity. In the present study, we investigated whether MMP-2 causes peritoneal injury. METHODS: To create an animal model of peritoneal injury, we administered intraperitoneally chlorhexidine gluconate to rats. Dialysate drained from these rats was analysed by gelatin zymography and MMP-2 activity was analysed by an in situ film zymography method. In vitro myofibroblasts were cultured in collagen three-dimensional culture and then MMP-2 in conditioned medium from the culture was analysed by gelatin zymography. RESULTS: Zymographic analysis revealed that latent form MMP-2 levels were high in the dialysate from peritoneal injury rats, whereas the active form was barely detectable. MMP-2 activity in the peritoneal tissue of the peritoneal injury rats was strongly detected by in situ film zymography. In vitro myofibroblasts were promoted to produce MMP-2 and to activate MMP-2 in collagen three-dimensional culture. CONCLUSIONS: In the present model, most of the MMP-2 was in the latent form, but activation of MMP-2 was promoted in the peritoneum during peritoneal injury. Activated MMP-2 may be associated with the progression of peritoneal injury.     

Connective tissue growth factor increases matrix metalloproteinase-2 and suppresses tissue inhibitor of matrix metalloproteinase-2 production by cultured renal interstitial fibroblasts

The involvement of gelatinase (matrix metalloproteinase-2 [MMP-2] and MMP-9) in the matrix remodeling and development of tubulointerstitial fibrosis has been studied recently, but relatively little is known about the regulators and the mechanisms controlling the activation and expression of gelatinase in renal fibroblasts. In these studies, the production and underlying signaling pathway for gelatinase by exogenous connective tissue growth factor (CTGF) treatment were investigated. Here, we show that CTGF acts as a potent promoter of the activation and expression of MMP-2, but not MMP-9 in normal rat kidney fibroblasts cell line (NRK-49F). We found that CTGF significantly increased the activity of MMP-2, as well as MMP-2 protein in conditioned medium and MMP-2 mRNA levels in cells. In studies to address the mechanisms involved in the regulation of MMP-2 activity, we found that the tissue inhibitor of matrix metalloproteinase-2 (TIMP-2), the inhibitor of MMP-2, decreased significantly when cells were treated with CTGF. Further studies showed that extracellular signal-regulated kinase (ERK) signaling is responsible for most of the CTGF-induced MMP-2 expression and TIMP-2 suppression. When NRK-49F fibroblasts were incubated with CTGF, activation of ERK1/2 signaling was observed. Suppression of ERK1/2 activation with nontoxic concentrations of PD98059, a specific inhibitor of ERK activation, was associated with a reduction of CTGF-stimulated MMP-2 activity and protein expression. In addition, the CTGF-mediated reduction of TIMP-2 activity and protein expression was prevented when ERK1/2 activation was inhibited by PD98059. These results provide evidence that CTGF augments activation of MMP-2 through an effect on MMP-2 protein expression and TIMP-2 suppression, and that these effects are dependent on the activation of the ERK1/2 pathway.     

黄芪、太子参对大鼠肾小球系膜细胞MMP-2及TIMP-2-mRNA表达的影响

目的：观察黄芪、太子参对大鼠肾小球系膜细胞基质金属蛋白酶-2（matrix metalloproteinase-2,MMP-2）及基质金属蛋白酶抑制剂-2（tissue inhibitor of metalloproteinase-2,TIMP-2）-mRNA表达的影响。探讨黄芪、太子参对肾小球硬化的防治作用。方法：（1）应用血清药理学方法,制取中药的药理血清。（2）采用血管紧张素Ⅱ（angiotensinⅡ,AngⅡ）作为刺激因子,培养大鼠肾小球系膜细胞,使其发生增殖。（3）应用反转录多聚酶链反应技术（RT-PCR）观察各组间MMP-2及TIMP-2m-RNA表达的情况。结果：黄芪、太子参对TIMP-2有显著地抑制作用,与对照组比较差异有统计学意义（P〈0.05）。对MMP-2的影响差异无统计学意义。结论：黄芪、太子参通过抑制TIMP-2的基因表达,从而达到延缓肾小球硬化的作用。     

基质金属蛋白酶-9及其抑制因子在肾细胞癌组织中的表达和意义

目的　探讨基质金属蛋白酶 9(MMP 9)和金属蛋白酶组织抑制因子 1(TIMP 1)在肾细胞癌中的表达及其与临床病理参数之间的关系。方法　采用免疫组织化学链霉菌抗生物素蛋白过氧化酶 (SP)法检测 5 5例肾细胞癌中MMP 9和TIMP 1的表达情况。结果　MMP 9、TIMP 1蛋白在肾细胞癌和正常肾组织中的阳性表达率各为 63 .63 %和 10 .0 0 % (P <0 .0 5 ) ;60 .0 0 %和10 .0 0 % (P <0 .0 5 )。在肾癌中 ,MMP 9蛋白表达与肿瘤Robson分期、肾包膜侵袭和淋巴结转移密切相关 (P <0 .0 5 ) ,而与组织学类型无关 (P >0 .0 5 ) ;TIMP 1蛋白表达与肾细胞癌的临床病理参数无关 (P >0 .0 5 )。结论　MMP 9蛋白高表达参与了肾癌的发展 ,MMP 9和TIMP 1的平衡失调可能在肾癌的侵袭转移中发挥重要作用。     

甲状旁腺素对人肾小管上皮细胞细胞外基质合成与降解的影响

目的 研究甲状旁腺素（PTH）对人肾小管上皮细胞（HK-2）合成分泌Ⅲ型胶原、纤连蛋白以及对纤溶酶原激活物抑制物1（PAI-1）、基质金属蛋白酶1（MMP-1）、金属蛋白酶1组织抑制剂（TIMP-1）基因表达的影响,以探讨PTH在肾间质纤维化发病机制中的作用。 方法 HK-2细胞培养于含5％ FBS的DMEM-F12培养液中,加入终浓度为0、10-12、10-11、10-10、10-9、10-8 mol/L PTH的培养液刺激HK-2细胞48 h,或10-8 mol/L PTH刺激HK-2细胞不同时间（0、12、24、48、72 h）。应用半定量RT-PCR法检测细胞中Ⅲ型胶原、纤连蛋白、PAI-1、MMP-1、TIMP-1基因的表达;Western印迹法检测HK-2细胞中Ⅲ型胶原的蛋白表达;ELISA法检测细胞培养上清液中纤连蛋白的含量。 结果 PTH 呈剂量和时间依赖性促进HK-2细胞中Ⅲ型胶原、纤连蛋白、PAI-1、TIMP-1 mRNA的表达,抑制MMP-1 mRNA的表达,MMP-1/TIMP-1 比值降低。PTH呈剂量和时间依赖性增加HK-2细胞中Ⅲ型胶原的蛋白表达及细胞培养上清液中纤连蛋白的含量。 结论 PTH通过促进HK-2细胞中PAI-1、TIMP-1的基因表达,抑制MMP-1的基因表达,导致细胞外基质合成增加而降解减少。     

Specific changes in plasma concentrations of matrix metalloproteinase-2 and -9, TIMP-1 and TGF-beta1 in patients with distinct types of primary glomerulonephritis.

BACKGROUND: Dysregulated renal expression of matrix metalloproteinases (MMPs), tissue inhibitors of MMPs (TIMP) and TGF-beta1 contribute to the development of tubulo-interstitial fibrosis characteristic of progressive forms of primary glomerulonephritis (GN). There is little information on the circulating levels of these proteins in human GNs. Here, we assessed whether different histopathological GN types could be associated with distinct plasma patterns of MMPs and regulatory proteins. METHODS: Protein levels of MMP-2, MMP-9, TGF-beta1 and TIMP-1 were measured by ELISA in plasma from venous blood of 108 untreated patients with various types of primary GN defined by kidney biopsy, namely IgAN (n=63), membranous GN (MN, n=26), minimal change nephrotic syndrome (MCNS, n=12) and focal and segmental glomerular sclerosis (FSGS, n=7), and were compared with levels in 50 healthy subjects. Plasma samples were assayed for gelatinolytic activity (zymography). RESULTS: Zymography detected the proforms of MMP-2 and MMP-9. Compared with controls, IgAN patients exhibited a significant, parallel decrease in plasma levels of MMP-2, MMP-9 and TGF-beta1. In MN patients, decreased MMP-9 level contrasted with a high MMP-2 level and a normal TGF-beta1 level. In the MCNS/FSGS group, increased MMP-2 level contrasted with unchanged MMP-9 and decreased TGF-beta1 levels. Plasma concentration of TIMP-1 was elevated in all GN groups. There was no correlation between baseline MMP-2/MMP-9/TIMP-1/TGF-beta1 levels and the degree of renal dysfunction or with progression toward ESRD. CONCLUSIONS: Plasma concentrations of MMP-2, MMP-9 and TGF-beta1 significantly differed between the various histopathological types of primary GNs, thus suggesting the involvement of different underlying mechanisms in the regulation of glomerular and tubulointerstitial fibrosis in these renal diseases.