Laporte J D, Moore P E, Panettieri R A, Moeller W, Heyder J, Shore S A
Physiology Program, Harvard School of Public Health, Boston, Massachusetts 02115, USA.
Am J Physiol. 1998 Sep;275(3):L491-501. doi: 10.1152/ajplung.1998.275.3.L491.
We have previously reported that pretreatment of cultured human airway smooth muscle (HASM) cells with interleukin-1beta (IL-1beta) results in decreased beta-adrenergic responsiveness. The purpose of this study was to determine whether prostanoids released as a result of cyclooxygenase-2 (COX-2) induction by IL-1beta contribute to this effect of the cytokine. Confluent serum-deprived HASM cells were studied in passages 4-7. IL-1beta (20 ng/ml for 22 h) reduced the ability of the beta-agonist isoproterenol (Iso) to decrease stiffness of HASM cells as measured by magnetic twisting cytometry. The effect of IL-1beta on Iso-induced changes in cell stiffness was abolished by nonselective [indomethacin (Indo), 10(-6) M] and selective (NS-398, 10(-5) M) COX-2 inhibitors. Indo and NS-398 also inhibited both the increased basal cAMP and the decreases in Iso-stimulated cAMP production induced by IL-1beta. IL-1beta (20 ng/ml for 22 h) caused an increase in both basal (15-fold) and arachidonic acid (AA)-stimulated (10-fold) PGE2 release. Indo blocked basal and AA-stimulated PGE2 release in both control and IL-1beta-treated cells. NS-398 also markedly reduced basal and AA-stimulated PGE2 release in IL-1beta-treated cells but had no significant effect on AA-stimulated PGE2 release in control cells. Western blot analysis confirmed the induction of COX-2 by IL-1beta. Exogenously administered PGE2 (10(-7) M, 22 h) caused a significant reduction in the ability of Iso to decrease cell stiffness, mimicking the effects of IL-1beta. Cycloheximide (10 microg/ml for 24 h), an inhibitor of protein synthesis, also abolished the effects of IL-1beta on Iso-induced cell stiffness changes and cAMP formation. In summary, our results indicate that IL-1beta significantly increases prostanoid release by HASM cells as a result of increased COX-2 expression. The prostanoids appear to contribute to beta-adrenergic hyporesponsiveness, perhaps by heterologous desensitization of the beta2 receptor.
我们之前曾报道，用白细胞介素-1β（IL-1β）预处理培养的人气道平滑肌（HASM）细胞会导致β-肾上腺素能反应性降低。本研究的目的是确定由IL-1β诱导环氧化酶-2（COX-2）释放的前列腺素是否促成了这种细胞因子的作用。在第4至7代研究汇合的血清饥饿HASM细胞。IL-1β（20 ng/ml，作用22小时）降低了β-激动剂异丙肾上腺素（Iso）降低HASM细胞硬度的能力，这通过磁扭细胞术测量。非选择性[吲哚美辛（Indo），10^(-6) M]和选择性（NS-398，10^(-5) M）COX-2抑制剂消除了IL-1β对Iso诱导的细胞硬度变化的影响。Indo和NS-398还抑制了IL-1β诱导的基础cAMP增加以及Iso刺激的cAMP产生减少。IL-1β（20 ng/ml，作用22小时）导致基础（15倍）和花生四烯酸（AA）刺激（10倍）的PGE2释放增加。Indo阻断了对照细胞和IL-1β处理细胞中的基础和AA刺激的PGE2释放。NS-398也显著降低了IL-1β处理细胞中的基础和AA刺激的PGE2释放，但对对照细胞中AA刺激的PGE2释放没有显著影响。蛋白质印迹分析证实了IL-1β对COX-2的诱导。外源性给予PGE2（10^(-7) M，22小时）导致Iso降低细胞硬度的能力显著降低，模拟了IL-1β的作用。蛋白质合成抑制剂放线菌酮（10 μg/ml，作用24小时）也消除了IL-1β对Iso诱导的细胞硬度变化和cAMP形成的影响。总之，我们的结果表明，由于COX-2表达增加，IL-1β显著增加了HASM细胞的前列腺素释放。前列腺素似乎促成了β-肾上腺素能低反应性，可能是通过β2受体的异源脱敏。
