MECHANISMS OF MG2+ TRANSPORT IN SUBLINGUAL ACINAR CELLS

研究表明，镁离子缺乏是引起糖尿病的重要因素 在许多疾病和紊乱中，可能包括唾液腺 功能障碍 美国人口的很大一部分，多达75%， 可能面临潜在的Mg 2+缺乏症。 Mg 2+在许多方面起着关键作用。 细胞功能，例如，Mg 2+与ATP形成复合底物， 柠檬酸盐等; Mg 2+是激酶、磷酸酶和 Mg 2+稳定膜和核糖体的结构 在蛋白质合成过程中; Mg 2+调节离子通道，交换剂， 协同转运体和泵活动。 我们发现Mg 2+有效地 调节细胞内Na+浓度，影响细胞内Na+浓度， 大鼠舌下腺泡细胞的pH值。 由于细胞内pH和Na+水平 对于调节体液分泌过程非常重要，Mg 2+可能 在调节外分泌功能中起重要作用 唾液腺 然而，细胞Mg 2+稳态的调节是 仍然知之甚少。 在初步研究中，我们发现在大鼠中， 舌下腺泡细胞，细胞内游离Mg 2+浓度为 由质膜中的Mg 2+转运系统和 胞内Mg 2+池。 Mg 2+从细胞内池中迁移 可能依赖于Ca 2+，尽管Mg 2+运输的潜在机制 在质膜和细胞内池中的作用仍然未知。 因此，在本发明中， 本项目的目的是探索Mg 2+的吸收和流出 在质膜和细胞内池的途径。 1)我们将 使用以下方法表征质膜中的Mg 2+转运途径： Mg 2+敏感荧光指示剂mag-fura-2，用于监测Mg 2+内流 和挤出分离的舌下腺泡或单细胞， 阳离子通道阻滞剂、激活剂和离子交换抑制剂， 表征Mg 2_流入和流出途径。 此外，我们将申请 蛋白激酶C激活剂和抑制剂以及操纵 细胞内cAMP水平，以阐明Mg 2+的调节机制 剂. 2)我们将探讨Mg 2+吸收和释放的机制， 细胞内Mg 2+池，特别是Ca 2+在Mg 2+中的作用 运动 在本项目中，我们将阐明Ca 2+在Mg 2+中的作用， 通过操纵细胞内游离Ca 2+的摄取和释放 浓度. 这些研究的结果将为以下方面提供见解： 阐明了Mg ~（2+）和Mg ~（2+）对唾液分泌的调节机制， 预防和治疗与Mg 2+相关的唾液腺功能障碍 缺陷

Studies indicate that Mg2+ deficiency is an important etiological factor in many diseases and disorders, possibly including salivary gland dysfunction. A large proportion of the U.S. population, as many as 75%, may face a latent Mg2+ deficiency. Mg2+ plays a critical role in many cell functions, for example, Mg2+ forms complex substrates with ATP, citrate, etc.; Mg2+ is a co-factor for kinases, phosphatases, and synthetases; Mg2+ stabilizes the structure of membranes and ribosomes during protein synthesis; and Mg2+ regulates ion channel, exchanger, cotransporter, and pump activities. We found that Mg2+ effectively regulates the intracellular Na+ concentration and affects intracellular pH in rat sublingual acinar cells. Since intracellular pH and Na+ level are very important for regulating the fluid secretion process, Mg2+ may play a vital role in the modulation of the secretory function of exocrine salivary glands. However,the regulation of cell Mg2+ homeostasis is still poorly understood. In preliminary studies, we found that in rat sublingual acinar cells, the intracellular free Mg2+ concentration is regulated by the Mg2+ transport systems in the plasma membrane and by an intracellular Mg2+ pool. Mg2+ mobilization from the intracellular pool may depend on Ca2+, although the underlying mechanisms of Mg2+ transport in the plasma membrane and intracellular pool are still unknown. thus, the purpose of this project is to explore the Mg2+ uptake and efflux pathways in the plasma membrane and intracellular pool. 1) we will characterize the Mg2+ transport pathways in the plasma membrane using Mg2+-sensitive fluorescent indicator, mag-fura-2, to monitor Mg2+ influx and extrusion in isolated sublingual acini or single cells, and using cation channel blockers, activators, and ion exchange inhibitors to characterize the Mg2_ influx and efflux pathways. Also, we will apply the activators and inhibitors of protein kinase C and manipulate intracellular cAMP levels to clarify the regulatory mechanism of Mg2+ fluxes. 2) we will explore the mechanisms of Mg2+ uptake and release in the intracellular Mg2+ pool, in particular the role of Ca2+ in Mg2+ movement. In this project, we will clarify the role of Ca2+ in Mg2+ uptake and release by manipulating the intracellular free Ca2+ concentration. The results from these studies will provide insight for elucidating the regulatory mechanism of saliva secretion by Mg2+ and in preventing and treating salivary gland dysfunctions associated with Mg2+ deficiency.