Le Magueresse-Battistoni B, Pernod G, Kolodié L, Morera A M, Benahmed M
INSERM U-407, Batiment 3B, Centre Hospitalier Lyon-Sud, Pierre-Benite, France.
Endocrinology. 1997 Mar;138(3):1097-105. doi: 10.1210/endo.138.3.4963.
We examined the regulation by tumor necrosis factor-alpha (TNF alpha) of plasminogen activator inhibitor-1 (PAI-1) in cultured peritubular cells recovered from 20-day-old rat testes. We demonstrated that TNF alpha in a nanomolar dose range stimulated PAI-1 messenger RNA (mRNA; Northern blots) as well as immunoreactive (Western blots) and bioactive (Stachrom) PAI-1 protein. Induction of PAI-1 mRNA started 4 h after the addition of TNF alpha (2.5-fold increase) and peaked (7-fold increase) after 24 h of treatment. Actinomycin D and cycloheximide inhibited the effects of TNF alpha on PAI-1 mRNA, suggesting that ongoing RNA and protein syntheses were required. The combined actions of transforming growth factor-alpha (TGF alpha), a potent inducer of PAI-1, and TNF alpha on PAI-1 were less than additive, suggesting the activation of some common pathway. TNF alpha action on PAI-1, like that of TGF alpha demonstrated previously, was masked by a preexposure to phorbol myristate acetate (a stimulator of protein kinase C) and strongly reduced by staurosporine (an inhibitor of the protein kinase C). Furthermore, using genistein to inhibit tyrosine kinase activity, we not only blocked the action of TGF alpha on PAI-1 [initiated upon binding to the tyrosine kinase epidermal growth factor/TGF alpha receptor (EGFR)], but also markedly reduced that of TNF alpha. Finally, TNF alpha, at a dose range that stimulated PAI-1, enhanced EGFR mRNA levels and EGF binding. Together, the present findings suggest that some of the biological effects of TNF alpha on PAI-1 might be secondary to de novo synthesis of EGFR. Because TNF alpha probably originates from testicular macrophages, such a regulation of PAI-1 by TNF alpha may occur in the context of physiological interactions between the testis and the immune system.
我们研究了肿瘤坏死因子-α（TNFα）对从20日龄大鼠睾丸中分离出的培养肾小管周细胞中纤溶酶原激活物抑制剂-1（PAI-1）的调控作用。我们发现，纳摩尔剂量范围的TNFα可刺激PAI-1信使核糖核酸（mRNA；Northern印迹法）以及免疫反应性（Western印迹法）和生物活性（Stachrom）PAI-1蛋白。添加TNFα后4小时开始诱导PAI-1 mRNA（增加2.5倍），处理24小时后达到峰值（增加7倍）。放线菌素D和环己酰亚胺可抑制TNFα对PAI-1 mRNA的作用，表明需要持续的RNA和蛋白质合成。转化生长因子-α（TGFα，一种PAI-1的强效诱导剂）与TNFα对PAI-1的联合作用小于两者单独作用之和，提示存在一些共同的信号通路被激活。TNFα对PAI-1的作用，与先前证明的TGFα的作用一样，在预先暴露于佛波酯肉豆蔻酸酯乙酸盐（一种蛋白激酶C的刺激剂）后被掩盖，而被星形孢菌素（一种蛋白激酶C的抑制剂）强烈降低。此外，使用染料木黄酮抑制酪氨酸激酶活性，我们不仅阻断了TGFα对PAI-1的作用[该作用在与酪氨酸激酶表皮生长因子/TGFα受体（EGFR）结合后启动]，而且还显著降低了TNFα的作用。最后，在刺激PAI-1的剂量范围内，TNFα可提高EGFR mRNA水平和EGF结合能力。总之，目前的研究结果表明，TNFα对PAI-1的一些生物学效应可能继发于EGFR的从头合成。由于TNFα可能起源于睾丸巨噬细胞，TNFα对PAI-1的这种调控可能发生在睾丸与免疫系统的生理相互作用过程中。
