MECHANISMS OF MG2+ TRANSPORT IN SUBLINGUAL ACINAR CELLS

舌下腺泡细胞中 MG2 转运机制

• 批准号: 3425907
• 负责人: GUO HE ZHANG
• 金额: $ 3.83万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-03-01 至 1995-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3425907
• 关键词: acinar cell; calcium; calcium indicator; cell membrane; cyclic AMP; enzyme inhibitors; fluorimetry; intracellular; ion transport; laboratory rat; magnesium; membrane channels; protein kinase C; single cell analysis; sublingual gland

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.

研究表明MG2+缺乏是重要的病因。 在许多疾病和疾病中，可能包括唾液腺 功能障碍。 美国人口中很大一部分，多达75％ 可能面临潜在的MG2+缺陷。 MG2+在许多人中起着至关重要的作用 例如，细胞函数，mg2+与ATP形成复杂底物 柠檬酸盐等； MG2+是激酶，磷酸酶和 合成酶； MG2+稳定膜和核糖体的结构 在蛋白质合成期间； MG2+调节离子通道，交换器， 共转运者和泵活动。 我们发现MG2+有效 调节细胞内Na+浓度并影响细胞内 大鼠舌下腺细胞中的pH。 由于细胞内pH和Na+水平 对于调节流体分泌过程非常重要，Mg2+可能 在外分泌的分泌功能的调节中起着至关重要的作用 唾液腺。 但是，细胞MG2+稳态的调节是 仍然很了解。 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MG2+浓度为 由质膜中的MG2+传输系统和 细胞内MG2+池。 MG2+来自细胞内池的动员 尽管MG2+转运的基本机制可能取决于Ca2+ 在质膜中，细胞内池仍然未知。 因此， 该项目的目的是探索MG2+摄取和排出 质膜和细胞内池中的途径。 1）我们会的 使用使用MG2+传输途径在质膜中使用 MG2+ - 敏感的荧光指示器Mag-Fura-2，以监视MG2+涌入 并在孤立的舌下Acini或单个细胞中挤出，并使用 阳离子通道阻滞剂，激活剂和离子交换抑制剂 表征MG2_涌入和外排途径。 另外，我们将申请 蛋白激酶C的激活剂和抑制剂并操纵 细胞内营地水平阐明MG2+的调节机制 通量。 2）我们将探索MG2+摄取的机制并释放 细胞内MG2+池，特别是Ca2+在Mg2+中的作用 移动。 在这个项目中，我们将阐明Ca2+在MG2+中的作用 通过操纵细胞内游离CA2+的吸收和释放 专注。 这些研究的结果将为 阐明MG2+和IN唾液分泌的调节机制 防止和治疗与MG2+相关的唾液腺功能障碍 不足。