钙化血管平滑肌细胞肾上腺髓质素及其受体系统的基因表达上调

探讨钙化的血管平滑肌细胞肾上腺髓质素生成和肾上腺髓质素受体系统一降钙素受体样受体和受体活性修饰蛋白基因表达的改变及其病理意义。采用β-甘油磷酸盐诱导培养的大鼠血管平滑肌细胞钙化;放射免疫法测定血管平滑肌细胞分泌的肾上腺髓质素含量;半定量逆转录聚合酶链反应测定细胞肾上腺髓质素、降钙素受体样受体和受体活性修饰蛋白的mRNA水平;原子吸收分光光度计测定细胞钙含量;碱性磷酸酶试剂盒测定血管平滑肌细胞碱性磷酸酶活性;β液体闪烁计数仪测定45Ca2+放射活性。结果发现,与非钙化血管平滑肌细胞比较,钙化血管平滑肌细胞内钙含量、45Ca2+摄入及碱性磷酸酶活性分别增加118％、174％和7倍(P<0.01);钙化细胞肾上腺髓质素分泌量增高99％(P<0.01),肾上腺髓质素、降钙素受体样受体、受体活性修饰蛋白2和3的mRNA水平分别增加78％、93.7％、91.8％和109.5％(P均<0.01)。肾上腺髓质素与降钙素受体样受体、受体活性修饰蛋白2和3的mRNA水平呈正相关,其相关系数分别为0.83、0.92和0.93(P均<0.01)。结果提示,血管平滑肌细胞肾上腺髓质素 旁/自分泌功能改变可能参与血管钙化的调节过程。     

转化生长因子β的丝裂原激活蛋白激酶通路与肝纤维化

转化生长因子β(transforming growth factor-β,TGF-β)是一个结构相关生长因子大家族的一员,这个家族包括TGF-β、激活素和骨形成蛋白。TGF-β是一个多功能的生长因子,由多种细胞产生,对细胞的生长、分化、迁移、凋亡及细胞外基质(extra-cellular matrix,ECM)的生成发挥调节作用,但在病理情况下,TGF-β是肝纤维化最主要的促纤维形成细胞因子。在纤维化形成过程中活化的肝星状细胞     

激活素对神经损伤作用的研究进展

激活素(activin)最初是作为垂体前叶的调节因子于1986年被分离和纯化的,能够刺激卵泡刺激素(FSH)的分泌.激活素属于转化生长因子-β(TGF-β)超家族的多功能生长和分化因子,分布广泛,在初期胚形成、神经细胞分化发育、造血细胞增殖和分化、细胞凋亡及癌肿形成、性激素分泌等方面发挥重要的调节作用~([1]).     

人重组骨形成蛋白-7对高糖诱导的肾系膜细胞转化生长因子-β1及结缔组织生长因子表达的影响

目的 探讨人重组骨形成蛋白-7(rhBMP-7)对高糖诱导的大鼠肾小球系膜细胞转化生长因子-β1(TGF-β1)、结缔组织生长因子(CTGF)基因表达及细胞外基质(ECM)成分Ⅳ型胶原(ColⅣ)和纤维黏连蛋白(FN)分泌的影响.方法 体外培养大鼠肾小球系膜细胞,分为四组:正常对照组(DMEM培养基含1 000 mg/L葡萄糖)、高糖组(DMEM培养基含4 500 mg/L葡萄糖)、rhBMP-7低剂量组(DMEM培养基含4 500 mg/L葡萄糖+50 nmol/L rhBMP-7)、rhBMP-7高剂量组(DMEM培养基含4 500 mg/L葡萄糖+100 nmol/L rhBMP-7).RT-PCR技术检测TGF-β1和CTGF基因表达水平,ELISA技术检测上清液中TGFβ1、ColⅣ、FN含量.结果 高糖组系膜细胞TGF-β1和CTGF mRNA水平明显高于正常对照组(P<0.01),TGF-β1、ColⅣ和FN分泌增多,与正常对照组比较,差异有统计学意义(P<0.05);与高糖组比较,rhBMP-7不同剂量(50、100 ng/ml)TGF-β1和CTGF mRNA表达明显降低,培养上清中TGF-β1、ColⅣ及FN分泌量亦明显减少,且差异显著(P<0.05).结论 RhBMP-7通过抑制高糖诱导的大鼠肾小球系膜细胞TGF-β1、CTGF基因表达和ECM的分泌可能起到抗纤维化作用.     

转化生长因子-β1对人近端肾小管上皮细胞结缔组织生长因子表达的影响

目的:探讨转化生长因子-β1(TGF-β1)对人肾小管上皮细胞结缔组织生长因子(CTGF)表达的影响,同时观察TGF-β1对肾小管上皮细胞合成细胞外基质(ECM)、组织金属蛋白酶抑制剂-1(TIMP-1)及α-平滑肌肌动蛋白(α-SMA)的影响.方法:应用逆转录-聚合酶链反应(RT-PCR)技术,观察TGF-β1诱导人近端肾小管上皮细胞系(HK-2)合成CTGF、ECM、TIMP-1及α-SMA的情况.结果:在无TGF-β1刺激的情况下,HK-2细胞中有基础量的CTGF mRNA表达,TGF-β1以剂量和时间依赖的方式诱导HK-2细胞合成CTGF mRNA,其表达在24h时达高峰,同时TGF-β1可使HK-2细胞合成ECM、α-SMA增多,但在时相上均晚于CTGF.随着TGF-β1浓度的增加,HK-2细胞合成TIMP-1也随之增加,但较大剂量的TGF-β1(15ng/ml)方可使TIMP-1 mRNA的表达明显增加(P＜0.05).结论:TGF-β1可直接诱导体外培养的人近端肾小管上皮细胞表达CTGF,其表达转录水平要早于ECM、α-SMA的表达,提示CTGF可能介导了TGF-β1的促肾小管上皮细胞ECM合成和转分化的作用.     

转化生长因子β1与肝纤维化的基因治疗

肝纤维化是一个极为复杂的病理过程,其形成的关键环节是肝脏星状细胞(HSC)的活化并转化成为肌纤维样母细胞(MFB),进而合成、分泌大量细胞外基质(ECM),导致ECM代谢失衡.在人们所发现的哺乳动物转化生长因子β(transforming growth factor beta,TGF-β)超家族中,TGF-β1是其中的主要成员,它既能抑制肝细胞、内皮细胞、上皮细胞的增殖,诱导细胞外基质的形成,又可以诱导肝细胞凋亡,是HSC向MFB转化进程中最重要的促进因子.因此,抑制TGF-β1生成,从分子水平阻断TGF-β1的信号转导,才有可能从"源头"上中止肝纤维化的形成.本文将从抑制TGF-β1的产生,阻断其与受体结合以及调控其胞内信号转导过程三个方面对近年来转化生长因子β1与肝纤维化的实验性基因治疗研究状况作一综述.     

转化生长因子β1在肝纤维化研究及应用中的意义

肝纤维化是肝脏受损伤之后细胞外基质(ECM)尤其是Ⅰ、Ⅲ、Ⅳ型胶原过度增生沉积、降解减少造成的病理性结果。既往对ECM的生成与沉积研究较多,近年对ECM降解的研究也日益深入,在ECM降解过程中,基质金属蛋白酶(MMPs)及其抑制因子(TIMPs)的平衡及转化生长因子-β1(TGF-β1)起着至关重要的作用。TGF-β1是组织生长、修复炎症的重要细胞转化生长因子。分子生物学研究显示,TGF-β1与肝纤维化的发生     

腺病毒介导反义Smad4基因大鼠体内转移对实验性肝纤维化的治疗作用

肝纤维化本质是过多的细胞外基质(extracellular matrix，ECM)沉积于肝内。转化生长因子(TGF)-β1是最重要的促肝纤维化因子，它能促进肝贮脂细胞(HSC)合成胶原、纤维连接蛋白及蛋白多糖等ECM，抑制基质金属蛋白酶(MMP)合成，并促进HSC分泌组织金属蛋白酶Ⅰ抑制剂(TIMP-1)等从而减少ECM降解。Smad4是TGF-β信号传导通路中的一个关键性因子，因此，我们将腺病毒介导的反义Smad4基因转移至大鼠体内，观察其对CCl4／乙醇诱导大鼠肝纤维化模型的影响。     

转化生长因子beta1在肝纤维化中的作用

肝纤维化是多种慢性肝病共有的组织学改变,它不仅是慢性肝炎向肝硬变发展的必经之路,而且贯穿于肝硬变的始终.目前认为,许多致病因素如HBV、HCV、血吸虫、酒精等,通过直接作用和(或)其介导的免疫病理损害,使肝细胞反复受损.同时,贮脂细胞、窦状内皮细胞、Kupffer细胞等间质细胞合成并分泌大量的细胞外基质(ECM),导致肝纤维化.肝间质细胞对ECM的分泌作用由多种细胞因子介导并调节.其中,转化生长因子β1(TGF-β1)在肝纤维化的形成过程中的作用逐渐被大家认识,本文通过总结近年来有关TGF-β1的研究进展,对TGF-β1的结构、来源、生物学活性及其对肝纤维化的作用作一综述.     

转化生长因子β1在肝纤维化中的作用

肝纤维化是多种慢性肝病共有的组织学改变,它不仅是慢性肝炎向肝硬变发展的必经之路,而且贯穿于肝硬变的始终.目前认为,许多致病因素如HBV、HCV、血吸虫、酒精等,通过直接作用和(或)其介导的免疫病理损害,使肝细胞反复受损.同时,贮脂细胞、窦状内皮细胞、Kupffer细胞等间质细胞合成并分泌大量的细胞外基质(ECM),导致肝纤维化.肝间质细胞对ECM的分泌作用由多种细胞因子介导并调节.其中,转化生长因子β1(TGF-β1)在肝纤维化的形成过程中的作用逐渐被大家认识,本文通过总结近年来有关TGF-β1的研究进展,对TGF-β1的结构、来源、生物学活性及其对肝纤维化的作用作一综述.     

Complement factor H genotypes impact risk of age-related macular degeneration by interaction with oxidized phospholipids

The rs1061170T/C variant encoding the Y402H change in complement factor H (CFH) has been identified by genome-wide association studies as being significantly associated with age-related macular degeneration (AMD). However, the precise mechanism by which this CFH variant impacts the risk of AMD remains largely unknown. Oxidative stress plays an important role in many aging diseases, including cardiovascular disease and AMD. A large amount of oxidized phospholipids (oxPLs) are generated in the eye because of sunlight exposure and high oxygen content. OxPLs bind to the retinal pigment epithelium and macrophages and strongly activate downstream inflammatory cascades. We hypothesize that CFH may impact the risk of AMD by modulating oxidative stress. Here we demonstrate that CFH binds to oxPLs. The CFH 402Y variant of the protective rs1061170 genotype binds oxPLs with a higher affinity and exhibits a stronger inhibitory effect on the binding of oxPLs to retinal pigment epithelium and macrophages. In addition, plasma from non-AMD subjects with the protective genotype has a lower level of systemic oxidative stress measured by oxPLs per apolipoprotein B (oxPLs/apoB). We also show that oxPL stimulation increases expression of genes involved in macrophage infiltration, inflammation, and neovascularization in the eye. OxPLs colocalize with CFH in drusen in the human AMD eye. Subretinal injection of oxPLs induces choroidal neovascularization in mice. In addition, we show that the CFH risk allele confers higher complement activation and cell lysis activity. Together, these findings suggest that CFH influences AMD risk by modulating oxidative stress, inflammation, and abnormal angiogenesis.     

Factor H autoantibodies in atypical hemolytic uremic syndrome correlate with CFHR1/CFHR3 deficiency

Atypical hemolytic uremic syndrome (aHUS) is a severe renal disease that is associated with defective complement regulation caused by multiple factors. We previously described the deficiency of factor H-related proteins CFHR1 and CFHR3 as predisposing factor for aHUS. Here we identify in an extended cohort of 147 aHUS patients that 16 juvenile individuals (ie, 11%) who either lacked the CFHR1/CFHR3 completely (n = 14) or showed extremely low CFHR1/CFHR3 plasma levels (n = 2) are positive for factor H (CFH) autoantibodies. The binding epitopes of all 16 analyzed autoantibodies were localized to the C-terminal recognition region of factor H, which represents a hot spot for aHUS mutations. Thus we define a novel subgroup of aHUS, termed DEAP HUS (deficiency of CFHR proteins and CFH autoantibody positive) that is characterized by a combination of genetic and acquired factors. Screening for both factors is obviously relevant for HUS patients as reduction of CFH autoantibody levels represents a therapeutic option.     

Adrenomedullin gene delivery attenuates hypertension, cardiac remodeling, and renal injury in deoxycorticosterone acetate-salt hypertensive rats

Adrenomedullin (AM) is a potent vasodilator and natriuretic peptide that plays an important role in cardiorenal function. In this study, we explored the potential protective role of AM in volume-dependent hypertension by somatic gene delivery. Adenovirus containing the human AM cDNA under the control of the cytomegalovirus promoter/enhancer was administered into deoxycorticosterone acetate (DOCA)-salt hypertensive rats via tail vein injection. A single injection of the human AM gene resulted in a prolonged reduction of blood pressure with a maximal reduction of 41 mm Hg 9 days after gene delivery. Human AM gene delivery enhanced renal function, as indicated by a 3-fold increase in renal blood flow and a 2-fold increase in glomerular filtration rate (n=5, P<0.05). Histological examination of the kidney revealed a significant reduction in glomerular sclerosis, tubular injury, luminol protein cast accumulation, and interstitial fibrosis as well as urinary protein. Human AM gene delivery caused significant decreases in left ventricular weight and cardiomyocyte diameter, which were accompanied by reduced interstitial fibrosis and extracellular matrix formation within the heart. Expression of human AM mRNA was detected in the kidney, adrenal gland, heart, aorta, lung, and liver; immunoreactive human AM levels were measured in urine and plasma. Significant increases in urinary and cardiac cAMP levels were observed in DOCA-salt rats receiving the human AM gene, indicating activation of the AM receptor. These findings showed that AM gene delivery attenuates hypertension, protects against cardiac remodeling and renal damage in volume-overload hypertension, and may have significance in therapeutic applications in cardiovascular and renal diseases.     

Atypical hemolytic-uremic syndrome related to abnormalities within the complement system

Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy (TMA) disorder characterised by the association of haemolytic anaemia, thrombocytopenia and acute renal failure. Atypical forms (non-shigatoxin related forms) may be familial or sporadic, frequently with relapses and most of them lead to end stage renal failure. During the last years, different groups have demonstrated genetic predisposition to atypical HUS (aHUS) involving five genes encoding for complement components which play a role in the activation or control of the alternative pathway: encoding factor H (CFH), accounting for 30% of aHUS; CD46 (encoding membrane cofactor protein [MCP]) accounting for approximately 10% of aHUS; CFI (encoding factor I) accounting for an estimated 5-15% of patients; C3 (encoding C3) accounting for approximately 10% of aHUS; and rarely CFB (encoding factor B). Predisposition to aHUS is inherited with incomplete penetrance. It is admitted that mutations confer a predisposition to develop aHUS rather than directly causing the disease and that a second event (genetic or environmental) is required for disease manifestation. HUS onset follows a triggering event in most cases (frequently banal seasonal infection and pregnancy). Uncontrolled C3 convertase leads to increased deposition of C3b on vascular endothelium and participates to the prothrombotic state. The phenotype of aHUS is variable ranging from mild forms, with complete recovery of renal function to severe forms with end stage renal disease within the first year after the onset. Overall, the outcome is severe with a mortality rate of 10% and with more than 60% of patients on dialysis. The most severe prognosis was in the CFH mutation group. There is a high risk of recurrence of the disease after renal transplantation in patients with mutations in CFH, CFI, CFB and C3. Plasma therapy may allow complete haematological remission but frequently with persistent renal damage. Some patients are plasma resistant and some are plasma dependent. The recent progress in the determination of the susceptibility factors for aHUS, have allowed to propose new diagnostic tests including a molecular genetic testing and may permit to consider some new specific treatments in this disease (human plasma-derived CFH or complement inhibitors).     

罗格列酮对高糖诱导下大鼠肾小球系膜细胞增殖及细胞周期的影响

以大鼠肾小球系膜细胞株(HBZY-1)为靶细胞,观察不同浓度不同时间罗格列酮(RSG)对高糖培养的系膜细胞的作用,发现RSG在一定范围内以剂量和时间依赖关系抑制高糖诱导的肾小球系膜细胞增殖,阻止系膜细胞由G1期进入S期,并诱导细胞凋亡。RSG有效减轻了高糖诱导的肾小球系膜细胞的病理损伤。     

Cardiac adrenomedullin: its role in cardiac hypertrophy and heart failure

Co-localization of adrenomedullin (AM) and its receptor components such as calcitonin receptor like receptor (CRLR), receptor activity modifying protein (RAMP)2 and RAMP3 in peripheral tissues, including the heart, kidney, and vasculature, suggests an important role for the peptide as a regulator of cardiovascular function. Indeed, we previously reported that AM gene expression and / or immunoreactivity are increased in the ventricles of cardiac hypertrophy and heart failure. Recently, we also found that not only levels of AM peptide and AM gene expression, but also mRNA levels of CRLR, RAMP2 and RAMP3 are increased in cardiac hypertrophy and failing heart. Cardiac myocytes and fibroblast produce and secrete two molecular forms of AM and express CRLR, RAMP2 and RAMP3, and AM is known to have inhibitory effect of collagen synthesis and antiproliferative effect in cardiac fibroblasts. Stimulation by IL-1beta significantly increased gene expression of AM and its receptor components in cardiac fibroblasts. Preincubated IL-1beta elevated the intracellular cAMP response to exogenous administered AM. AM antisense oligodeoxynucleotide treatment significantly lowered AM levels in cultured medium. IL-1beta significantly increased (3)H-proline incorporation and AM antisense oligodeoxynucleotide treatment further increased (3)H-proline incorporation. Collectively, these results support a protective role for increased AM in the cardiac hypertrophy and heart failure. Then, we tested the effects of acute administration of AM in experimental and human heart failure, because AM has hemodynamic effects including vasodilation, increases in cardiac contractility, cardiac output, diuresis, and natriuresis. We observed profound and sustained cardiovascular, hormonal and renal effects. These effects may incorporate many of the therapeutic goals of heart failure management.     

Membrane cofactor protein and factor I: mutations and transplantation

Mutations in the genes for three complement regulators-complement factor H (CFH), membrane cofactor protein (MCP), and factor I (IF)-have now been described in patients with atypical HUS. The functional effects of these mutations have been studied in detail and have been shown to affect secretion, expression, and regulatory function. Genotype-phenotype correlations have shown that the majority of patients with CFH, MCP, and FI mutations develop end-stage renal failure. The outcome of transplantation is poor in patients known to have either a CFH or FI mutation, with approximately 80% of patients losing the graft to recurrent disease within 2 years. In contrast, patients known to have only an MCP mutation have a satisfactory transplantation outcome. This is expected because MCP is a transmembrane regulator and allografts will therefore be protected by wild-type MCP. Combined liver/kidney transplantation for patients known to have a CFH mutation has not been successful to date. There is optimism that in the future, targeted complement inhibitors will be of major therapeutic benefit in this condition.     

Alterations of intrarenal adrenomedullin and its receptor system in heart failure rats

Calcitonin receptor-like receptor/receptor activity-modifying protein 2 (CRLR/RAMP2) and CRLR/RAMP3 complexes have been reported to be specific adrenomedullin (AM) receptors. In the present study, we evaluated the pathophysiological significance of renal AM and its receptor system in aortocaval shunt (ACS) rats. Renal AM levels were measured serially during 5 weeks after the operation. Renal gene expressions of AM, CRLR, RAMP2, and RAMP3 were measured at 2 weeks (decompensated phase) and 5 weeks (compensated phase) after the operation. Immunohistochemical localizations of renal AM were also evaluated. Furthermore, the relations between urinary sodium excretion (UNaV) and renal AM levels were evaluated. Renal AM levels were higher in ACS than in control animals only at 1, 2, and 3 weeks after the operation. At 2 weeks after the operation, renal AM mRNA expression was also higher in ACS than in control animals. CRLR, RAMP2, and RAMP3 mRNAs were expressed in the kidney, but there were no differences between the 2 groups. Immunohistochemistry revealed the positive AM immunostaining within the renal tubular cells, and it was more intense in ACS than in control animals. There were significant correlations between UNaV and renal AM levels. At 5 weeks after the operation, there were no differences in mRNA levels of AM, CRLR, RAMP2, and RAMP3 between the 2 groups. There was a significant correlation between UNaV and medullary AM levels. The present findings suggest that increased renal AM levels in decompensated heart failure, presumably due to increased AM production in renal tubules, in part, are involved in the regulation of sodium excretion.     

Usefulness of combining complement factor H and C-reactive protein genetic profiles for predicting myocardial infarction (from the Rotterdam Study)

Complement factor H (CFH) is an important regulator of the complement cascade. Binding of C-reactive protein (CRP) to CFH augments the ability of CFH to downregulate the effect of complement in atherosclerotic lesions. The CFH Tyr402His polymorphism has been suggested to influence the ability of CFH to bind CRP. We hypothesized that the combined presence of unfavorable CRP and CFH genetic profiles is associated with risk of myocardial infarction (MI). The Rotterdam Study is a population-based cohort study in 7,983 men and women aged > or =55 years. The CFH Tyr402His (rs1061170) polymorphism was determined (His(402) allele 37%), and using 3 tagging polymorphisms (rs1130864, rs1205, and rs3093068), CRP haplotypes were inferred (1 = CTC, 2 = TCC, 3 = CCC, 4 = CCG; frequencies of 33%, 32%, 30%, and 6%, respectively). Participants were grouped by CFH genotype (TyrTyr [reference], TyrHis, and HisHis) and CRP haplotype (haplotype 1 homozygotes [reference], haplotype 2 carriers, haplotype 3 carriers, and haplotype 4 carriers), which resulted in a total of 12 groups. CFH His(402) homozygotes who were also CRP haplotype 3 carriers had an age- and gender-adjusted hazard ratio of 5.9 (95% confidence interval 2.1 to 16.5) to develop MI compared with the reference group. In conclusion, this population-based study suggests that the combined presence of unfavorable CFH and CRP genetic profiles is associated with risk of MI.     

Genetics of HUS: the impact of MCP, CFH, and IF mutations on clinical presentation, response to treatment, and outcome

Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy with manifestations of hemolytic anemia, thrombocytopenia, and renal impairment. Genetic studies have shown that mutations in complement regulatory proteins predispose to non-Shiga toxin-associated HUS (non-Stx-HUS). We undertook genetic analysis on membrane cofactor protein (MCP), complement factor H (CFH), and factor I (IF) in 156 patients with non-Stx-HUS. Fourteen, 11, and 5 new mutational events were found in MCP, CFH, and IF, respectively. Mutation frequencies were 12.8%, 30.1%, and 4.5% for MCP, CFH, and IF, respectively. MCP mutations resulted in either reduced protein expression or impaired C3b binding capability. MCP-mutated patients had a better prognosis than CFH-mutated and nonmutated patients. In MCP-mutated patients, plasma treatment did not impact the outcome significantly: remission was achieved in around 90% of both plasma-treated and plasma-untreated acute episodes. Kidney transplantation outcome was favorable in patients with MCP mutations, whereas the outcome was poor in patients with CFH and IF mutations due to disease recurrence. This study documents that the presentation, the response to therapy, and the outcome of the disease are influenced by the genotype. Hopefully this will translate into improved management and therapy of patients and will provide the way to design tailored treatments.