■糖尿病的胃肠道症状,慢性便秘,严重影响患者的生活。然而,慢性便秘的机制仍然不明确,导致这种症状缺乏有效的治疗方法。作为平滑肌细胞的一部分,Cajal间质细胞,和血小板衍生生长因子受体α阳性(PDGFRα)细胞合胞体(SIP合胞体),PDGFRα+细胞在调节结肠运动中起重要作用。根据我们之前的研究,在糖尿病小鼠结肠的PDGFRα+细胞中,P2Y1嘌呤受体/3型小电导钙激活钾(SK3)通道信号通路的功能得到加强,这可能会导致结肠运动障碍。目的探讨糖尿病小鼠PDGFRα+细胞SK3通道特性的变化。
■全细胞膜片钳,西方印迹,超氧化物歧化酶活性测定,丙二醛的测定是本研究的主要方法。
■本研究表明,当用低钙离子(Ca2)溶液透析时,糖尿病小鼠PDGFRα+细胞的SK3电流密度明显降低。然而,当用高Ca2溶液透析时,糖尿病小鼠PDGFRα细胞中的SK3电流密度增强。此外,过氧化氢处理在SK3转基因HEK293细胞中模拟了这种现象。SK3通道的亚基,蛋白激酶CK2在结肠肌肉层和过氧化氢处理的HEK293细胞中上调。此外,蛋白磷酸酶2A,SK3通道的子单元,在链脲佐菌素处理的小鼠结肠或过氧化氢处理的HEK293细胞中没有变化。
■糖尿病氧化应激诱导的CK2上调有助于调节结肠PDGFRα+细胞中SK3通道对Ca2+的敏感性,这可能导致糖尿病小鼠的结肠运动障碍。
UNASSIGNED: The gastrointestinal symptom of diabetes mellitus, chronic constipation, seriously affects patients\' life. Whereas, the mechanism of chronic constipation is still ambiguous, resulting in a lack of effective therapies for this symptom. As a part of the smooth muscle cells, interstitial cells of Cajal, and platelet-derived growth factor receptor alpha-positive (PDGFRα+) cells syncytium (SIP syncytium), PDGFRα+ cells play an important role in regulating colonic motility. According to our previous study, in PDGFRα+ cells in colons of diabetic mice, the function of the P2Y1 purinergic receptor/type 3 small-conductance calcium-activated potassium (SK3) channel signaling pathway is strengthened, which may lead to colonic dysmotility. The purpose of this study is to investigate the changes in SK3 channel properties of PDGFRα+ cells in diabetic mice.
UNASSIGNED: Whole-cell patch clamp, Western blotting, superoxide dismutase activity measurement, and malondialdehyde measurement were main methods in the present study.
UNASSIGNED: The present study revealed that when dialysed with low calcium ion (Ca2+) solution, the SK3 current density was significantly decreased in PDGFRα+ cells from diabetic mice. However, the SK3 current density in PDGFRα+ cells was enhanced from diabetic mice when dialysed with high Ca2+ solution. Moreover, hydrogen peroxide-treatment mimicked this phenomenon in SK3 transgenic HEK293 cells. The subunit of SK3 channels, protein kinase CK2, was up-regulated in colonic muscle layers and hydrogen peroxide-treated HEK293 cells. Additionally, protein phosphatase 2A, the subunit of SK3 channels, was not changed in streptozotocin-treated mouse colons or hydrogen peroxide-treated HEK293 cells.
UNASSIGNED: The diabetic oxidative stress-induced upregulation of CK2 contributed to modulating SK3 channel sensitivity to Ca2+ in colonic PDGFRα+ cells, which may result in colonic dysmotility in diabetic mice.