First Dept. of Medicine, Univ. of Szeged, H-6720, Korányi fasor 8-10, Szeged, Hungary.
Am J Physiol Gastrointest Liver Physiol. 2013 Oct 15;305(8):G552-63. doi: 10.1152/ajpgi.00394.2012. Epub 2013 Aug 1.
Gastrointestinal myofibroblasts are contractile, electrically nonexcitable, transitional cells that play a role in extracellular matrix production, in ulcer healing, and in pathophysiological conditions they contribute to chronic inflammation and tumor development. Na+/Ca2+ exchangers (NCX) are known to have a crucial role in Ca2+ homeostasis of contractile cells, however, no information is available concerning the role of NCX in the proliferation and migration of gastrointestinal myofibroblasts. In this study, our aim was to investigate the role of NCX in the Ca2+ homeostasis, migration, and proliferation of human gastrointestinal myofibroblasts, focusing on human gastric myofibroblasts (HGMs). We used microfluorometric measurements to investigate the intracellular Ca2+ and Na+ concentrations, PCR analysis and immunostaining to show the presence of the NCX, patch clamp for measuring NCX activity, and proliferation and migration assays to investigate the functional role of the exchanger. We showed that 53.0±8.1% of the HGMs present Ca2+ oscillations, which depend on extracellular Ca2+ and Na+, and can be inhibited by NCX inhibitors. NCX1, NCX2, and NCX3 were expressed at both mRNA and protein levels in HGMs, and they contribute to the intracellular Ca2+ and Na+ homeostasis as well, regardless of the oscillatory activity. NCX inhibitors significantly blocked the basal and insulin-like growth factor II-stimulated migration and proliferation rates of HGMs. In conclusion, we showed that NCX plays a pivotal role in regulating the Ca2+ homeostasis, migration, and proliferation of HGMs. The inhibition of NCX activity may be a potential therapeutic target in hyperproliferative gastric diseases.
胃肠道肌纤维母细胞是具有收缩性、无电兴奋性的过渡细胞，在细胞外基质的产生、溃疡愈合以及在病理生理条件下促进慢性炎症和肿瘤发展等方面发挥作用。已知钠钙交换器 (NCX) 在收缩细胞的钙稳态中具有重要作用，然而，关于 NCX 在胃肠道肌纤维母细胞的增殖和迁移中的作用尚没有信息。在这项研究中，我们的目的是研究 NCX 在人胃肠道肌纤维母细胞（HGMs）的钙稳态、迁移和增殖中的作用，重点研究人胃肌纤维母细胞（HGMs）。我们使用微荧光测量法来研究细胞内 Ca2+和 Na+浓度，PCR 分析和免疫染色显示 NCX 的存在，膜片钳测量 NCX 活性，以及增殖和迁移测定来研究交换器的功能作用。我们表明，53.0±8.1%的 HGMs 存在 Ca2+振荡，这依赖于细胞外 Ca2+和 Na+，并且可以被 NCX 抑制剂抑制。NCX1、NCX2 和 NCX3 在 HGMs 中均在 mRNA 和蛋白质水平上表达，并且无论振荡活性如何，它们都有助于细胞内 Ca2+和 Na+的稳态。NCX 抑制剂显著阻断了 HGMs 的基础和胰岛素样生长因子 II 刺激的迁移和增殖率。总之，我们表明 NCX 在调节 HGMs 的钙稳态、迁移和增殖中起着关键作用。抑制 NCX 活性可能是治疗过度增殖性胃部疾病的潜在治疗靶点。
