Raymond P, Bouvier M, Drapeau G, Blais C, Morais R, Adam A
Faculté de Pharmacie, Université de Montréal, Québec, Canada.
Peptides. 1996;17(7):1171-6. doi: 10.1016/s0196-9781(96)00180-5.
Using the rat H4-II-E-C3 hepatoma cell line, we investigated the presence of [125I][Tyr8]BK binding sites and the direct modulation of T-kininogen synthesis, an acute phase protein of inflammation, by bradykinin (BK) analogues. H4-II-E-C3 membrane preparations exhibited [125I][Tyr8]BK binding sites with a Kd of 4 nM and a Bmax of 120 fmol/mg of protein. Des-Arg9-BK showed no affinity (Ki > 10(-4) M) for these sites. The B2 metabolism-resistant and selective agonist [Phe8 psi (CH2-NH)Arg9]BK decreased the T-kininogen concentration in H4-II-E-C3 medium by 23% (p < 0.05). This effect was reversed by coincubation with the B2 antagonist HOE140. The B1 agonist Sar[D-Phe8]des-Arg9-BK and the B1 antagonist Lys[Leu8]des-Arg9-BK did not modify T-kininogen concentrations. The interaction between cytokines and kinins in the modulation of T-kininogen synthesis was also studied. Preincubation of hepatoma cells for 1 h with interleukin-1 alpha (IL-1 alpha) alone reduced T-kininogen concentrations by 37%, and this effect was blocked by co-addition of HOE140. Preincubation with interleukin-6 (IL-6) increased T-kininogen levels by threefold. Coincubation in the presence of the B2 agonist decreased this augmentation by 24%. The latter effect was reversed by co-addition of HOE140. None of the cytokines tested induced a response to the B1 agonist or antagonist under the experimental conditions studied. Overall, these results support the presence of a functional B2 receptor on H4-II-E-C3 cells that modulates T-kininogen synthesis. We suggest that the receptor is involved in vivo in a retroaction loop between kinins and T-kininogen production during inflammation. We speculate that BK could be a mediator in the modulation of acute phase protein synthesis by the cytokines IL-1 alpha and IL-6.
利用大鼠H4-II-E-C3肝癌细胞系，我们研究了[125I][Tyr8]缓激肽（BK）结合位点的存在情况，以及BK类似物对炎症急性期蛋白T-激肽原合成的直接调节作用。H4-II-E-C3细胞膜制剂表现出[125I][Tyr8]BK结合位点，解离常数（Kd）为4 nM，最大结合容量（Bmax）为120 fmol/mg蛋白质。去精氨酸9-缓激肽（Des-Arg9-BK）对这些位点无亲和力（抑制常数Ki>10(-4) M）。抗B2代谢且具有选择性的激动剂[Phe8ψ(CH2-NH)Arg9]BK使H4-II-E-C3培养基中的T-激肽原浓度降低了23%（p<0.05）。与B2拮抗剂HOE140共同孵育可逆转此效应。B1激动剂Sar[D-Phe8]去精氨酸9-缓激肽和B1拮抗剂Lys[Leu8]去精氨酸9-缓激肽不改变T-激肽原浓度。我们还研究了细胞因子和激肽在调节T-激肽原合成中的相互作用。肝癌细胞单独用白细胞介素-1α（IL-1α）预孵育1小时可使T-激肽原浓度降低37%，而HOE140的共同添加可阻断此效应。用白细胞介素-6（IL-6）预孵育可使T-激肽原水平增加三倍。在B2激动剂存在下共同孵育可使这种增加减少24%。HOE140的共同添加可逆转后一种效应。在所研究的实验条件下，所测试的细胞因子均未诱导对B1激动剂或拮抗剂的反应。总体而言，这些结果支持H4-II-E-C3细胞上存在功能性B2受体，其可调节T-激肽原的合成。我们认为该受体在体内炎症过程中激肽与T-激肽原产生之间的反馈回路中发挥作用。我们推测BK可能是细胞因子IL-1α和IL-6调节急性期蛋白合成的介质。
