The mechanism of Ca2+ ion inflow regulated by KF506 binding proteins (FKBP) and Calcineurin.

我们研究了FKBPs(FK506结合蛋白)和钙调神经磷酸酶对神经元和肌肉细胞内钙离子内流的调节机制。在疾病动物模型中，我们进一步探讨了钙离子内流的病理生理机制。使用已建立的和原代培养的细胞系统和大鼠肥大的膀胱模型进行研究。在两年的深入研究中，我们得到了如下结果：1)建立了胎鼠海马神经元的原代培养，并用谷氨酸和NMDA诱导了兴奋性神经元的死亡。2)我们发现钙调神经磷酸酶抑制剂FK506和环孢菌素A可以抑制兴奋性神经元的死亡，但不能抑制雷帕霉素。3)在兴奋性神经元死亡中，钙离子内流和钙调神经磷酸酶的连续激活是诱导神经元死亡的重要前提。4)激活的钙调神经磷酸酶诱导转录因子NF-AT从胞浆到胞核的移位。在一个肥大的膀胱模型中，1)肌动蛋白和肌球蛋白表达增加，钙调神经磷酸酶表达改变。2)钙调神经磷酸酶抑制剂FK506抑制膀胱肥大。3)肥大的膀胱平滑肌细胞通过依赖于ATP的钙通道钙离子内流增加。

We investigated the mechanism of Ca2+ ion inflow into neurons and muscle cells regulated by FKBPs (FK506 binding proteins) and Calcineurin. We further investigated Pathophysiological mechanism of Ca2+ inflow in animal model of diseases. Established and primary cultured cell systems and a rat hypertrophic urinary bladder model were used for this investigations. In intensive research for two years supported by this grant, we have got results as follows,1) We established primary culture of fetal rat hippocampal neurons and induced excitatory neuronal cell death by glutamate and NMDA.2) We showed that calcineurin inhibitors, FK506 and Cyclosporin A inhibited the excitatory neuronal cell death but not Rapamycin.3) In the excitatory neuronal cell death, the Ca2+ ion inflow and the successive activation of calcineurin is essentially important as prerequisites for the induction of neuron death.4) The activated calcineurin induced translocation of a transcription factor, NF-AT from cytoplasm to nuclear compartment of neurons.In a hypertrophic urinary bladder model,1) We showed the increment of actin and myosin expression and the change of calcineurin expression during hypertrophy induction.2) Calcineurin inhibitor, FK506 inhibited bladder hypertrophy.3) Hypertrophic bladder smooth muscle cells showed increased Ca2+ ion inflow through ATP dependent Ca channels.