Weerackody R P, Chatterjee P K, Mistry S K, McLaren J, Hawksworth G M, McLay J S
Department of Medicine and Therapeutics, University of Aberdeen, UK.
Exp Nephrol. 1997 May-Jun;5(3):253-62.
The proliferation and hypertrophy of renal tubular cells are primary features in the progression of both acute and chronic renal disease often indicating a poor prognosis. Angiotensin II (ANG II), acting alone or in combination with other growth factors, has been implicated in this process. The aims of this study were to identify the importance of both ANG II and serum-derived factors upon cellular DNA synthesis and protein synthesis in renal proximal tubular cells and to identify the roles of the ANG II receptor subtypes in these processes together with the underlying intracellular signalling mechanisms involved. Primary cultures of renal proximal tubular cells were prepared from freshly isolated rat kidney cortex. Cells were cultured in either serum-replete Dulbecco's modified Eagle's/Ham's F12 or serum-deplete defined medium containing insulin, hydrocortisone, sodium selenite, transferrin, and tri-iodothyronine. Cells were incubated with ANG II (10(-10), 10(-8), 10(-6) M) for 24-120 h either alone or in combination with losartan, PD123319, or pertussis toxin. Incubation of proximal tubular cells in the presence of serum and ANG II (10(-8) M) induced a significant early (24 h) increase in DNA synthesis, together with a significant late (96 h) increase in protein content. [3H]thymidine uptake increased by 56% (p < 0.001) and total protein content by 23% (p < 0.05). In defined media, ANG II (10(-8) M) stimulated protein synthesis only. [3H]uridine uptake, [3H]leucine uptake, and total protein content increased by 25, 57, and 17% (p < 0.05), respectively. In both serum-replete and serum-deplete media, the effects upon protein synthesis of ANG II were inhibited by pertussis toxin and losartan, but not by PD123319. ANG II is clearly a potent stimulator of renal tubular cell DNA and protein synthesis-a response mediated via the AT1 receptor coupled to a pertussis toxin sensitive Gi protein.
肾小管细胞的增殖和肥大是急性和慢性肾病进展的主要特征，常提示预后不良。血管紧张素II（ANG II）单独或与其他生长因子联合作用，与这一过程有关。本研究的目的是确定ANG II和血清衍生因子对肾近端小管细胞中细胞DNA合成和蛋白质合成的重要性，并确定ANG II受体亚型在这些过程中的作用以及所涉及的潜在细胞内信号传导机制。从新鲜分离的大鼠肾皮质制备肾近端小管细胞的原代培养物。细胞在富含血清的杜氏改良 Eagle's/Ham's F12培养基或含有胰岛素、氢化可的松、亚硒酸钠、转铁蛋白和三碘甲状腺原氨酸的无血清限定培养基中培养。细胞单独或与氯沙坦、PD123319或百日咳毒素联合，用ANG II（10(-10)、10(-8)、10(-6) M）孵育24 - 120小时。在血清和ANG II（10(-8) M）存在的情况下孵育近端小管细胞，可导致DNA合成在早期（24小时）显著增加，同时蛋白质含量在晚期（96小时）显著增加。[3H]胸苷摄取增加56%（p < 0.001），总蛋白质含量增加23%（p < 0.05）。在限定培养基中，ANG II（10(-8) M）仅刺激蛋白质合成。[3H]尿苷摄取、[3H]亮氨酸摄取和总蛋白质含量分别增加25%、57%和17%（p < 0.05）。在富含血清和无血清培养基中，ANG II对蛋白质合成的作用均被百日咳毒素和氯沙坦抑制，但不被PD123319抑制。ANG II显然是肾小管细胞DNA和蛋白质合成的有效刺激物——这一反应是通过与百日咳毒素敏感的Gi蛋白偶联的AT1受体介导的。
