Inhibition of cell proliferation in glomeruli using overexpression of anti-oxidative enzyme

慢性肾小球肾炎肾小球细胞增殖与晚期糖基化终产物等氧化产物的积聚密切相关，并伴有炎症细胞的侵袭。在含有细胞外基质的分化条件下，人肾小球系膜细胞表达EC-SOD。细胞外超氧化物歧化酶(EC-SOD)是由间充质来源的细胞合成的，具有保护氧自由基损伤的作用。我们研究了肾小球系膜细胞(MC)是否产生EC-SOD，以及其产生与趋化因子分泌的关系。在非刺激条件下，MCs产生EC-SOD，其产生与环磷酸腺苷(CAMP)呈正相关，与IL-6、IL-8产生呈负相关。经强的松龙或佛波酯处理后，EC-SOD水平与IL-6、IL-8水平呈负相关。腺苷环化酶抑制剂2‘，3’-二脱氧腺苷的存在使强的松龙作用消失。The…强的松龙通过cAMP途径对系膜细胞产生更多的超氧化物歧化酶可能是其重要作用之一。为了研究强的松龙对系膜区氧自由基的保护作用，我们测定了体外培养的系膜细胞产生的细胞外超氧化物歧化酶(EC-SOD)。这些细胞对细胞外空间中的氧自由基具有主要的保护作用。在含胎牛血清的“生长液”和含还原生长因子的“分化液”两种不同的培养条件下，分别加入I型胶原、IV型胶原、层粘连蛋白和纤维连接蛋白四种细胞外基质。分化培养基能诱导EC-SOD的高表达，与其抑制IL-6、IL-8产生和减缓细胞增殖有关。随着细胞外基质的不同，VI型胶原和层粘连蛋白的存在促进EC-SOD的产生比纤维连接蛋白和I型胶原更高。与以病理状态为主的I型胶原和纤维连接蛋白相比，IV型胶原和层粘连蛋白与肾小球的生理状态相关促进EC-SOD的产生。肾小球系膜增殖性肾炎系膜细胞增殖过程中EC-SOD生成受到抑制，与分化培养上清液相比，趋化因子生成增多，可能与肾小球系膜细胞对氧自由基毒性的保护能力降低类似。I型胶原和纤维连接蛋白可促进肾小球系膜细胞增殖，增加肾小球内氧自由基毒性，并通过抑制EC-SOD的生成而加速肾小球硬化。较少

Glomerular cell plorifrration in hronic glomerular nephritis was closely associated with the accumulation of the advanced glycation end products and other oxidative products with inflammatory cell invasion. Under the differentiated condition with extra-cellular matrix, human mesangial cel express the EC-SOD. Extracellular superoxide dismutase (EC-SOD) is synthesized in mesenchymally derived cells and prevents the oxygen radical-induced injury. We studied whether kidney mesangial cells (MCs) produce EC-SOD and how its production is associated with chemokine secretion. Under unstimulated condition, MCs produced EC-SOD, and its production was correlated positively with cyclic adenosine monophosphate (cAMP), but negatively with interleukin (IL)-6 or IL-8 production. By prednisolone or phorbol myristate acetate treatment, EC-SOD levels were correlated negatively with levels of IL-6 and IL-8. The presence of adenylate cyclase inhibitor 2',3'-dideoxyadenosine lost the prednisolone effect. The … More stimulation of EC-SOD production might be one of the important effects of prednisolone via cAMP pathway in MCs.To study the protective function against oxygen radicals in the mesangial area, we assessed extracellular superoxide dismutase (EC-SOD) production in mesangial cells (MCs) in vitro. These cells have a major protective function against oxygen radicals in the extracellular space. In two different kinds of culture conditions : "growth medium" with fetal cow serum, and "differentiation medium" with reduced growth factor, and four extracellular matrixes ; type I collagen, type IV collagen, laminin and fibronectin, were added to the MC culture. With the difference in the culture media, differentiation medium induced EC-SOD hyper-production associated with the both of the slowing down of cell proliferation and the suppression of IL-6 and IL-8 production. With difference in the extracellular matrix, the presence of type VI collagen and laminin promoted higher production of EC-SOD than fibronectin and type I collagen. Type IV collagen and laminin associated with the physiological condition of the glomeruli promoted EC-SOD production compared with the presence of type I collagen and fibronectin dominantly located in pathological condition. Suppression of EC-SOD production in growth medium along with MC proliferation and chemokine hyper-production compared with production in differentiation medium might mimic reduction of the protective capacity against oxygen radical toxity during mesangial proliferation in the glomerular nephritis. MC proliferation with type I collagen and fibronectin might enhance oxygen radical toxity in the glomeruli, and accelerate glomerular sclerosis through the suppression of EC-SOD production. Less