纤维连接蛋白或精甘天冬氨酸肽促进兔支气管上皮细胞NO合成

Fibronectin or RGD peptide promotes nitric oxide synthesis of rabbit bronchial epithelial cells

为验证细胞外基质成分纤维连接蛋白 (fibronectin ,Fn)对气道上皮细胞具有调控作用 ,本文用硝酸还原酶法测定了原代培养的兔支气管上皮细胞 (bronchialepithelialcells,BEC)的一氧化氮 (nitricoxide ,NO)释放 ,并测定了细胞内一氧化氮合酶 (nitricoxidesynthesase ,NOS)活性 ,观察纤维连接蛋白、精 甘 天冬氨酸肽 (Arg Gly Asppep tide ,RGD)处理的影响 ,设置臭氧攻击组为阳性对照。结果 :(1)臭氧攻击 2h后 ,NO释放增多 (P <0 0 1,n =7) ,Fn (15 μg/ml)也能增加NO释放 (P <0 0 1) ,并被钙调素抑制剂N (6 氨基己烷 ) 5 氯 1 萘酚 磺酰胺 (N (6 Amino hexyl) 5 chloro 1 naphthalene sulfonamide ,W7) (10 -5mol/L)所阻断 (P <0 0 1) ;(2 )Fn (5～ 2 0 μg/ml)及RGD (15～ 6 0μg/ml)均显示对NO释放量的剂量依赖性促进作用 (分别为r=0 85和r =0 89) ;(3)Fn (15 μg/ml)明显提高BEC的NOS活性 (P <0 0 1,n =7) ,此效应也能被W7阻断 (P <0 0 1)。Fn及RGD对NOS活性的上调有量 效关系 ,分别为r=0 93及r=0 90。结果提示 ,Fn及其特殊识别片段RGD肽与BEC整合素分子的结合 ,可上调细胞的NOS活性及NO释放 ,其效应发挥与钙调素途径有关。

To find out whether the extracellular matrix component fibronectin plays a regulatory and protective role in bronchial epithelial cells, the present study was undertaken to detect the NO released from primary cultured rabbit bronchial epithelial cells (BEC) and the activity of NO synthesase (NOS) in cells. Stress with ozone was taken as the positive control, and the effects of fibronectin (Fn) or its specific sequence Arg Gly Asp (RGD peptide) was observed. The results showed: (1) Ozone stress enhanced NO release from BEC, and treatment with Fn also promoted the NO production. The effect of Fn could be blocked by calmodulin inhibitor W 7. (2) Both Fn and RGD showed a dose dependent promotion on NO release. (3) The NOS activity was significantly elevated in Fn treated group and the effect of Fn was abolished by W 7. A dose response relation in NOS activity was observed in either Fn treated or RGD treated group. It is concluded that the binding of fibronectin or its specific sequence RGD peptide with integrins of BEC plays a role in upregulating the NOS activity and the NO release, and calmodulin may take part in the pathway of signal transduction.[WT5HZ]