Roles of TGF-beta1 and apoptosis in the progression of glomerulosclerosis in human IgA nephropathy

Apoptotic glomerular cells have been detected in the severely damaged glomeruli that are a consequence of human IgA nephropathy. Transforming growth factor-(TGF) beta1 is known to induce apoptosis in cultured mesangial cells. To clarify whether TGF-beta1 contributes to the progression of IgA nephropathy by activating apoptosis in glomerular cells, we examined the expression of TGF-beta1 gene and apoptotic changes in kidney biopsy samples, and assessed those relations to the severity of nephropathy. 32 patients with IgA nephropathy, showing proteinuria (> 1 g/day) and serum creatinine less than 1.5 mg/dl were classified according to glomerular sclerosis index (GSI) into 3 groups (Group I: GSI < 0.3,Group 11: 0.3 < or = GSI < 1.0, Group: III GSI > or = 1.0). Computer-aided morphometry of glomeruli and arteries, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling of fragmented DNA (TUNEL) staining were performed. Expression of TGF-beta1 and caspase-3 mRNAs in renal biopsy samples was analyzed by real-time PCR (Taq Man method). Increased glomerular area, interstitial fibrosis, lymphocytic infiltration, and tubulointerstitial changes were observed to accompany increased severity of GSI. TUNEL index was higher in Group III. The levels of TGF-beta1 and caspase-3 mRNAs were significantly increased in Group III (183 and 190%, respectively). Furthermore, caspase-3 mRNA levels were tightly associated with TGF-beta1 mRNA expression (r = 0.677, p < 0.0001). The present study suggests that the activation of TGF-beta1 plays a role in the progression of IgA nephropathy even in the moderate degree of glomerular injury, in part via activation of apoptosis of glomerular cells.     

Inhibition of glomerular cell apoptosis by heparin.

BACKGROUND: Heparin, the multifunctional glycosaminoglycan, has been considered a therapeutic agent for glomerular diseases. Although a number of biological properties are postulated to explain its therapeutic utility, it is unknown whether heparin affects cell survival in the glomerulus. In this report, we investigated the effect of heparin on apoptosis of glomerular cells. METHODS: Cultured rat mesangial cells were pretreated with heparin or heparan sulfate proteoglycan (HSPG) and were exposed to proapoptotic stimuli. To examine an effect of heparin on spontaneous apoptosis that occurs in explanted glomeruli, isolated rat glomeruli were incubated in the presence or absence of heparin. Apoptosis was evaluated by Hoechst 33258 staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, and agarose gel electrophoresis to detect DNA fragmentation. The effect of heparin on activator protein 1 (AP-1), a crucial mediator for oxidant-induced apoptosis, was examined by Northern blot analysis and a reporter assay. RESULTS: Heparin and HSPG inhibited apoptosis of mesangial cells triggered by hydrogen peroxide. It was associated with blunted expression of c-fos/c-jun mRNAs and suppression of AP-1 activation. The cytoprotective effect of heparin was also observed in other cell types and in apoptosis triggered by different stimuli. That is, (a) heparin inhibited mesangial cell apoptosis induced by staurosporine, pyrrolidine dithiocarbamate, and ultraviolet light, and (b) heparin suppressed oxidant-induced apoptosis of NRK49F fibroblasts and Madin-Darby canine kidney epithelial cells. Furthermore, heparin attenuated spontaneous apoptosis of podocytes in explanted glomeruli. CONCLUSIONS: These results indicate the novel potential of heparin as an inhibitor of apoptosis in several cell types, including glomerular cells.     

Retinoic acid regulation of mesangial cell apoptosis

Retinoic acid (RA) is recently used for the treatment of experimental glomerular diseases. However, mechanisms underlying its therapeutic effects are largely unknown. We recently reported that RA has the potential for protecting certain cells from particular injury. A typical example is its effect on oxidant-induced apoptosis of mesangial cells. Mesangial cells exposed to hydrogen peroxide undergo apoptosis through activation of the c-Jun N-terminal kinase activator protein 1 pathway. RA dramatically inhibits this process via suppression of c-fos/c-jun expression and inhibition of the c-Jun N-terminal kinase activation. The anti-apoptotic effect of RA is mediated by both nuclear receptor dependent and nuclear receptor independent mechanisms and is, at least in part, mediated by induction of mitogen-activated protein kinase phosphatase 1. In this review, we briefly summarize the current knowledge on molecular mechanisms involved in the anti-apoptotic effects of RA.     

Methylglyoxal induces apoptosis through activation of p38 mitogen-activated protein kinase in rat mesangial cells

BACKGROUND: The formation of methylglyoxal (MG), a highly reactive dicarbonyl compound, is accelerated through several pathways, including the glycation reaction under diabetic conditions, presumably contributing to tissue injury in diabetes. On the other hand, apoptotic cell death of glomerular cells has been suggested to play a role in the development of glomerulosclerosis in various types of glomerular injuries. We therefore examined whether MG was capable of inducing apoptosis in rat mesangial cells to address the possible mechanism by which hyperglycemia-related products accelerated pathologic changes in diabetic glomerulosclerosis. METHODS: Rat mesangial cells were incubated with 0 to 400 micromol/L MG, followed by the detection of apoptosis by both TUNEL method and electrophoretic analysis for DNA fragmentation. In addition, we investigated intracellular mechanisms mediating MG-induced apoptosis, focusing especially on the p38 mitogen-activated protein kinase (MAPK) pathway. RESULTS: MG induced apoptosis in rat mesangial cells in a dose-dependent manner and was accompanied by the activation of p38alpha isoform. Aminoguanidine and N-acetyl-l-cysteine inhibited the MG-induced p38 MAPK activation, as well as apoptosis in rat mesangial cells, suggesting the involvement of oxidative stress in these phenomena. SB203580, a specific inhibitor of p38 MAPK also suppressed the MG-induced apoptosis in rat mesangial cells. CONCLUSIONS: These results suggest a potential role for MG in glomerular injury through p38 MAPK activation under diabetic conditions and may serve as a novel insight into the therapeutic strategies for diabetic nephropathy.     

Anti-apoptotic effect of quercetin: intervention in the JNK- and ERK-mediated apoptotic pathways

BACKGROUND: Bioflavonoid quercetin inhibits hydrogen peroxide (H2O2)-induced apoptosis via intervention in the activator protein 1 (AP-1)-mediated apoptotic pathway. In this report, we investigated molecular events involved in the anti-apoptotic effect of quercetin, focusing especially on its effects on the family of mitogen-activated protein (MAP) kinases. METHODS: Cultured mesangial cells were exposed to H2O2, and activation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinases (ERKs), and p38 MAP kinase was evaluated in the presence or absence of quercetin. Using pharmacological and genetic inhibitors, the roles for individual MAP kinases in H2O2-induced apoptosis were examined. Involvement of ERKs in the induction and activation of AP-1 was also investigated using Northern blot analysis and a reporter assay. RESULTS: Mesangial cells exposed to H2O2 exhibited rapid phosphorylation of JNK, ERKs, and p38 MAP kinase. Quercetin abrogated the activation of all three MAP kinases in response to H2O2. Pretreatment with MAP kinase kinase inhibitor PD098059 or JNK-c-Jun/AP-1 inhibitor curcumin attenuated the H2O2-induced apoptosis. In contrast, the p38 MAP kinase inhibitor SB203580 did not improve the cell survival. Consistently, transfection with dominant-negative mutants of ERK1 and ERK2 or a dominant-negative mutant of JNK inhibited H2O2-induced apoptosis. Transfection with a dominant-negative p38 MAP kinase did not attenuate the apoptotic process. Inhibition of ERKs by PD098059 suppressed induction of c-fos without affecting early induction of c-jun, leading to attenuated activation of AP-1 in response to H2O2. CONCLUSIONS: These results suggested that (1) activation of JNK and ERKs, but not p38 kinase, is required for the H2O2-induced apoptosis; and (2) suppression of the JNK-c-Jun/AP-1 pathway and the ERK-c-Fos/AP-1 pathway is involved in the anti-apoptotic effect of quercetin.     

Endothelial cell apoptosis during glomerular capillary lumen formation in vivo

Transforming growth factor-beta (TGF-beta) stimulates endothelial cell apoptosis in vitro, and inhibition of TGF-beta1 leads to retention of undifferentiated endothelial cells in developing glomerular capillaries and reduced lumen formation in vivo. This study explored the question whether glomerular capillary lumen formation in vivo may involve TGF-beta1-dependent endothelial cell apoptosis. Neutralizing anti-TGF-beta1 or non-immune IgY were infused into the renal arteries of 3-d-old rats, and the kidneys were examined 2 d later. By transmission electron microscopy, endocapillary apoptotic cells were observed at a frequency of 0.10/loop in immature glomeruli of 3-d-old rat pups. In 5-d-old rat pups given neutralizing TGF-beta1 antibody or control IgY, the frequency of endocapillary apoptotic cells was 0.03 and 0.09/loop, respectively (P < 0.001, chi(2)). Dual labeling with TUNEL and anti-von Willebrand factor (vWF) antibody showed that apoptotic cells in immature glomeruli of 5-d-old rat pups are endothelial cells. Quantitative analysis showed significantly fewer TUNEL/vWF-labeled cells in glomeruli after anti-TGF-beta1 antibody infusion than in controls. No endocapillary apoptotic cells were observed in any group in C-shaped or S-shaped bodies, and the TUNEL assay revealed no glomerular apoptotic cells in kidneys from mature rats. These findings suggest that superfluous endothelial cells are cleared from immature glomerular capillaries by apoptosis, a process regulated by TGF-beta1. Taken together with the previous finding, that TGF-beta1 blockade blunts glomerular capillary lumen formation in vivo, it is proposed that TGF-beta1-dependent apoptosis serves to open capillary lumens in this vascular bed during glomerular development.     

Shedding of growth-suppressive gangliosides from glomerular mesangial cells undergoing apoptosis

BACKGROUND: Apoptosis of glomerular mesangial cells is a common feature in several types of glomerular diseases. However, its pathophysiologic significance is not known. We recently identified gangliosides as a major growth-inhibitory substance in the conditioned medium of mesangial cells. In this report, we tested whether biologically distinct forms of cell fate, apoptosis and necrosis, could modulate ganglioside shedding from mesangial cells. METHODS: Mesangial cells were exposed to low (10 to 40 mJ/cm2) and high (400 mJ/cm2) doses of ultraviolet light to induce apoptosis and necrosis, respectively. Conditioned media were collected and examined for its growth-inhibitory activity for mesangial cells. Ganglioside shedding was analyzed using metabolic labeling and thin-layer chromatography (TLC). RESULTS: Shedding of gangliosides as well as growth-inhibitory activity in the conditioned medium predominantly increased when mesangial cells were undergoing apoptosis in contrast to that of viable or necrotic mesangial cells. The inhibitory substance in the conditioned medium from apoptotic mesangial cells completely fulfilled the characteristic criteria of gangliosides. This substance was less than 3 kD and was sensitive to neuraminidase digestion. Shedding of gangliosides from mesangial cells reduced significantly when apoptosis was inhibited by overexpression of antiapoptotic gene, Bcl-XL. In addition, ganglioside shedding also increased when mesangial cells were exposed to other inducers of apoptosis for mesangial cells (i.e., H2O2 and staurosporin). CONCLUSION: These results provide the novel link between masangial cell apoptosis and increased release of gangliosides that potentially suppress mesangial cell proliferation and thus indicate a mechanism for the negative regulation of mesangial cell growth by apoptosis.     

槲皮素联合survivin反义核苷酸对肝癌细胞凋亡协同作用的研究

目的 探讨槲皮素联合survivin反义核苷酸(ASODN)对肝癌SSMC-7721细胞株增殖、凋亡和细胞周期的影响.方法 常规培养SSMC-7721细胞,用四甲基偶氮唑盐法(MTT法)评价survivin ASODN联合槲皮素对肝癌细胞增殖的影响;流式细胞仪(FCM)检测细胞凋亡率和细胞周期;荧光染色观察细胞形态学变化;并通过RT-PCR和免疫组化方法检测survivin基因表达变化.结果 survivin反义寡核苷酸转染SSMC-7721细胞后,可以显著抑制细胞增殖,其抑制作用具有剂量依赖性,且能诱导肝癌细胞凋亡;联合槲皮索和survivin反义寡核苷酸抑制作用更为显著(t=4.317,P<0.01);RT-PCR及免疫组化显示ASODN和槲皮素均使survivin mRNA和蛋白表达下降.结论 survivin基因反义寡核苷酸联合槲皮素能明显抑制肝癌SSMC-7721细胞增殖、诱导细胞凋亡和下调survivin基因表达;两者具有协同作用.     

15-Deoxy-Delta12,14-prostaglandin J2 regulates mesangial cell proliferation and death

BACKGROUND: Proliferation of intrinsic glomerular cells is a common response to renal injury. Acutely, proliferation may be beneficial, but sustained glomerular hypercellularity after injury is associated with progressive renal failure. To identify endogenous factors that may be responsible for regulating glomerular cell number, the effects of J-series cyclopentenone prostaglandins (PGs) on human glomerular mesangial cell proliferation and death were examined. METHODS: Human mesangial cells were grown in the presence or absence of PGJ2 or its metabolite 15-Deoxy-Delta12,14-PGJ2 (15dPGJ2). The number of viable cells was measured by the reduction of the tetrazolium MTS to a colored formazan product. Apoptosis was assessed by caspase-3 activation and DNA fragmentation. RESULTS: PGJ2 at concentrations up to 10 micromol/L caused mesangial proliferation. 15dPGJ2 also caused mesangial proliferation at low concentrations (< or =2.5 micromol/L), but induced mesangial cell death at higher concentrations (>5 micromol/L). Cell death occurred in part through apoptosis, measured as an increase in caspase-3 activity and DNA fragmentation in 15dPGJ2-treated cells. Cell death was associated with a decline in baseline phosphorylation of the survival factor Akt and increased Akt degradation, whereas 15dPGJ2-induced mesangial proliferation was blocked by inhibition of the PI 3-kinase/Akt pathway. 15dPGJ2 is a potent PPARgamma agonist. Like 15dPGJ2, treatment of mesangial cells with thiazolidinedione-type PPARgamma ligands (10 to 20 micromol/L) caused significant cell death, but at lower concentrations also caused a small degree of proliferation. CONCLUSIONS: J-series prostaglandins thus may be involved in the initiation of glomerular hypercellularity through Akt-dependent proliferation, and restoration of normal glomerular architecture through PPARgamma-mediated apoptosis. Manipulation of these prostaglandins may be relevant to the treatment of progressive glomerular disease.     

精甘天丝四肽对人肾小球系膜细胞肌动蛋白及凋亡的影响

观察精-甘-天-丝(RGDS)四肽对肾小球系膜细胞肌动蛋白及凋亡的影响,以探讨细胞外基质(ECM)-整合素-细胞骨架的相互作用机制。方法 共聚焦显微镜观察肾小球系膜细胞肌动蛋白微丝的变化;以流式细胞仪和DNA电泳方法检测细胞凋亡。结果 用RGDS肽处理2小时后,系膜细胞开始由梭形变为圆形或卵圆形,同时细胞质的肌动蛋白微丝亦由弥漫分布变为聚集成团,居于细胞质一侧,形成着边现象,这些细胞继而脱壁、悬浮于培养上清中,脱落细胞经碘化丙啶染色见细胞核固缩、破碎。至第10小时RGDS处理组的系膜细胞大都脱壁,脱落细胞的DNA电泳呈现梯形条带,流式细胞仪分析显示处理组系膜细胞中出现了低二倍体细胞群(A_0峰),证实处理组的脱落细胞发生了细胞凋亡。在实验观察期间对照组的系膜细胞始终呈贴壁状态生长,细胞质肌动蛋白微丝呈弥漫分布。结论 RGDS肽可以使肾小球系膜细胞细胞骨架肌动蛋白微丝分布异常,导致肾小球系膜细胞变形、脱壁和凋亡。     

Increased glomerular cell heparan sulfates in vitro by ciclosporin A: a Possible explanation of Its beneficial effect in idiopathic nephrotic syndrome

BACKGROUND/AIM: In idiopathic nephrotic syndrome (INS), ciclosporin A (CsA) was shown to decrease proteinuria, an effect explained by its immunologic and hemodynamic actions. In order to determine whether CsA could have a direct action on glomerular cells, we studied the effect of CsA on glomerular cells in vitro, particularly on glycosaminoglcycans (GAG) and heparan sulfates (HS) which are decreased in INS patients. METHODS: Human glomerular epithelial cells and rat mesangial cells were cultured at various concentrations of CsA. HS were quantified using a cationic membrane after metabolic labeling. RESULTS: Mesangial cell GAG and HS and epithelial cell HS increased significantly when cells were cultured with CsA. For both cell types this increase was prevailing on the secreted fraction of HS in comparison with the cellular fraction. CsA induced also an increase in cellular cAMP levels, but the effect of CsA was not transduced via a cAMP pathway. CONCLUSIONS: CsA is able to increase glomerular GAG and HS in vitro. As this effect of CsA was the opposite effect on glomerular cells to the effect of plasma from INS patients, we conclude that this direct action of CsA on glomerular cells could explain in part the effect of this drug in decreasing proteinuria in INS.     

TGF-beta1 regulates the PINCH-1-integrin-linked kinase-alpha-parvin complex in glomerular cells

Glomerular damage is a major cause of renal failure. Recent studies suggest that a ternary protein complex that consists of PINCH-1, integrin-linked kinase, and alpha-parvin, cytoplasmic components of cell-extracellular matrix adhesions, plays pivotal roles in regulation of glomerular cell behavior. It is reported here that TGF-beta1, a key factor in the progression of glomerular failure, regulates the PINCH-1-integrin-linked kinase-alpha-parvin (PIP) complex formation in glomerular podocytes and mesangial cells. Treatment of podocytes with TGF-beta1 inhibited the PIP complex formation. Forced disruption of the PIP complex in podocytes activated p38 mitogen-activated protein kinase and promoted apoptosis. Importantly, inhibition of p38 mitogen-activated protein kinase, either with a chemical p38 inhibitor (SB202190) or with a dominant negative form of p38alpha, alleviates podocyte apoptosis that is induced by the disruption of the PIP complex. In contrast to an inhibitory role in podocytes, TGF-beta1 promotes the PIP complex formation in mesangial cells. Thus, TGF-beta1 regulates the PIP complex in a cell type-dependent manner. Because the PIP complex promotes glomerular mesangial matrix deposition and protects podocytes from apoptosis, the TGF-beta1-induced up- and downregulation of the PIP complex likely contribute to the pleiotropic effects of TGF-beta1 on different glomerular cell types and hence the progression of glomerular failure.     

Gentamicin treatment induces simultaneous mesangial proliferation and apoptosis in rats

BACKGROUND: Gentamicin (G)-induced acute renal failure is characterized by an impairment of glomerular function without apparent changes in glomerular structure. However, G stimulates reactive oxygen species (ROS)-mediated mesangial cell proliferation in vitro. We studied whether G promotes mesangial cell apoptosis in vitro, and if apoptosis and proliferation in parallel may occur in glomerular cells in vivo after a renal damage induced by G treatment. METHODS: For in vivo studies, rats were treated with G (100 mg/kg body weight/day) for 6 days, and functional and histologic studies were performed. For in vitro studies, mesangial cell proliferation and apoptosis were evaluated after 24, 48, and 72 hours of 10(-5) mol/L G incubation. RESULTS: After G injections, the number of nuclei per glomerulus did not change, whereas proliferating and apoptotic cell numbers increased. G increases DNA synthesis and cell number in cultured mesangial cells, and increases markedly the apoptotic cell number. ROS scavengers superoxide dismutase and catalase reduce G-induced mesangial cell apoptosis, whereas the incubation with the ROS donor system xanthine plus xanthine oxidase increases apoptosis to levels similar to G. G-induced cellular proliferation and apoptosis either in vitro or in vivo is associated to an early increase in the pro-apoptotic protein Bax and a delayed increase in the survival protein Bcl-2. CONCLUSION: G simultaneously induces proliferation and apoptosis of mesangial cells in vitro and glomerular mesangial cells in vivo. ROS may mediate G-induced mesangial apoptosis in vitro. The equilibrium proliferation/apoptosis may maintain mesangial cell number within normal limits after a G-induced glomerular insult.     

尿毒清对晚期糖基化终末产物作用下肾小球系膜细胞影响

目的观察尿毒清对晚期糖基化终末产物（advanced glycosylation end products, AGEs）作用下肾小球系膜细胞的影响,探讨中药尿毒清在治疗糖尿病肾脏疾病（diabetic kidney dis-ease,DKD）中对肾小球系膜细胞的保护作用。方法采用冻干牛血清白蛋白和糖制备无内毒素的AGE-BSA及人工培养牛肾小球系膜细胞,培养时分为3组,在加入终浓度为0.25 mg/ml AGEs 的同时给予浓度为0.2 mg/ml的尿毒清成分溶液为尿毒清组,加入终浓度为0.25 mg/ml AGEs 为 AGEs组,同时设空白对照组,应用 MTT比色法,观察尿毒清组对体外 AGEs 培养的牛肾小球系膜细胞增殖的影响;以系膜细胞与 Alcain Blue（AB,阿利新蓝）结合量为指标,观察尿毒清组对 AGEs导致的系膜细胞膜表面电荷的影响;利用 AO/EB染料观察尿毒清组对 AGEs 诱导作用下的牛肾小球系膜细胞凋亡的影响,并利用荧光显微镜观察尿毒清的抑制作用。结果尿毒清组可以有效地抑制 AGEs对牛肾系膜细胞的促进增殖作用;对抗 AGEs 诱导的牛肾小球系膜细胞表面电荷的影响;减少 AGEs诱导的牛肾小球系膜细胞凋亡。结论尿毒清组能减少对晚期糖基化终末产物作用下肾小球系膜细胞增殖和凋亡,保护肾小球系膜细胞表面电荷。     

槲皮素对人肾癌细胞增殖、凋亡及stat3、survivin表达的影响

目的探讨槲皮素对人肾癌细胞增殖、凋亡及stat3、survivin表达的影响。方法在肾癌细胞体外培养的基础上,根据不同浓度槲皮素（20μmol／L、40μmol／L和80μmol／L）分别3组,即低、中、高浓度干预组;另设空白对照组。观察不同浓度的槲皮素对肾癌细胞增殖、凋亡及stat3、survivin的mRNA和蛋白表达的影响。采用MTT法检测槲皮素对细胞的毒性作用。用流式细胞仪检测细胞凋亡。Real Time PCR检测stag和survivin的mRNA表达,采用Western blot检测star3和survivin的蛋白表达。结果随作用时间延长和浓度增高,槲皮素对细胞增殖的抑制作用增强。各槲皮素干预组与空白对照组比较均具有统计学差异（P〈0．05）。在槲皮素作用48h时检测,槲皮素（20μmol／L）组细胞早期凋亡率为20．17％、槲皮素（40μmol／L）组细胞早期凋亡率为61．93％、槲皮素（80μmol／L）组细胞早期凋亡率为82．24％。各槲皮素干预组与空白对照组比较差异均有统计学意义（P〈0．05）。stat3与survivin mRNA之间呈直线相关关系（r=0．697,P=0．002）,且磷酸化staG（p-staG）和survivin蛋白也呈直线相关关系（r=0．748,P=0．003）。结论槲皮素可抑制肾癌细胞的增殖,诱导细胞凋亡,下调stat3和survivin的mRNA和蛋白表达。     

Efficacy of galectins in the amelioration of nephrotoxic serum nephritis in Wistar Kyoto rats

BACKGROUND: Galectins are characterized by specific affinity for beta-galactoside sugars, and they play a role in diverse biological processes, including cell adhesion, cell proliferation, and apoptosis. Galectin-1, -3, and -9 have been implicated in modulating the immune response. METHODS: Nephrotoxic serum nephritis, which is characterized by crescent formation and glomerular influx of CD8+ cells into glomerular capillaries, was induced in Wistar Kyoto (WKY) rats by injecting rabbit antiglomerular basement membrane serum. Following induction, the rats were treated either with phosphate-buffered saline or dexamethasone, galectin-1, galectin-3, or galectin-9 on alternate days and were sacrificed at day 14. At day 8, splenic lymphocytes were isolated and employed for terminal deoxytransferase-mediated uridine triphosphate nick end-labeling (TUNEL) assay to assess the degree of apoptosis, and the kidneys were utilized to determine the extent of influx of CD4(+) and CD8(+) cells and glomerular damage. RESULTS: Dexamethasone induced a marked apoptosis of splenic CD4(+) and CD8(+) cells, and it inhibited the production of anti-rabbit IgG and the influx of CD8+ cells and macrophages into the renal glomeruli. Crescent formation and excretion of urinary proteins were also reduced. Galectin-9 failed to induce apoptosis in the CD4(+) cells; however, it induced apoptosis in the CD8(+) cells and inhibited the infiltration of CD8(+) cells. Although galectin-1 and -3 did not induce the apoptosis in the T cells, they inhibited the accumulation of macrophages in the renal glomeruli. Like dexamethasone, the galectins also reduced the crescentic formation, proliferation of glomerular cells, and excretion of urinary proteins. CONCLUSIONS: Galectin-9 selectively induces apoptosis of the activated CD8(+) cells, while the macrophage influx into the kidney is modulated by all three galectins. This finding raises an interesting possibility for the utility of galectins in the modulation of macrophages that are involved in immune-mediated glomerular diseases.     

Histopathological atlas of renal diseases: ANCA-associated vasculitis (Second part)

In the first part of Histopathological Atlas of Renal Diseases we described the typical morphological features of Anca-associated vasculitis. The histological features in Wegener's granulomatosis, Micropolyarteritis and its renal-limited variant, are characterized by "pauci immune" necrotizing extracapillary glomerulonephritis. The cellular composition of glomerular crescent and the mechanisms underlying crescent formation are still incompletely understood. The recent availability of monoclonal antibodies directed against epithelial cells and leucocytes allowed a more precise identification of the crescent cells. In this chapter we will describe the prevalent presence of monocytes in the crescents, the possible mechanisms of recruitment of these cells and the morphological consequences of this glomerular infiltration for the chronic progression of lesions.