Pyruvate inhibits zinc-mediated pancreatic islet cell death and diabetes
Pyruvate inhibits zinc-mediated pancreatic islet cell death and diabetes
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DOI：
10.1007/s00125-003-1171-z
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发表时间：
2003-09-01
期刊：
影响因子：
8.2
通讯作者：
Lee, MS
中科院分区：
文献类型：
--
作者：
Chang, I;Cho, N;Lee, MS
目的/假设。我们已经表明，锌离子（Zn 2+）在胰腺β细胞分泌颗粒可以作为一个旁分泌死亡效应链脲佐菌素诱导的糖尿病。由于Zn 2+已被报道干扰糖酵解，我们研究了丙酮酸盐是否可以通过正常化细胞内能量代谢来抑制Zn 2+介导的体外胰岛细胞死亡和链脲佐菌素诱导的体内糖尿病。通过定量活细胞染色和Hoechst/碘化丙啶染色测量细胞死亡。ATP的测定采用生物发光法。丙酮酸通过尾静脉注入链脲佐菌素给药前1小时。β细胞体积通过含胰岛素细胞的点计数来测量。Zn ~（2+）可诱导MIN 6 N8胰岛素瘤细胞发生典型的坏死，并使细胞内ATP水平迅速下降。丙酮酸抑制Zn ~（2+）诱导的胰岛素瘤细胞坏死和Zn ~（2+）引起的细胞内ATP耗竭。丙酮酸不抑制其他类型的坏死或凋亡。能量底物，如草酰乙酸，α-酮戊二酸和琥珀酸二甲酯也衰减锌+诱导的胰岛素瘤细胞死亡。在细胞质中不产生NAD（+）的丙酮酸甲酯或仅在线粒体中刺激ATP产生的α-酮异己酸也保护胰岛素瘤细胞免受Zn 2+诱导的坏死。丙酮酸输注通过保护链脲佐菌素给药后的β细胞群抑制糖尿病的发展。这些结果表明，丙酮酸盐通过保护细胞内ATP水平来抑制体外Zn 2+诱导的β细胞坏死，并且还抑制体内链脲霉素诱导的糖尿病，其中已报道Zn 2+充当旁分泌死亡效应物。
Aims/hypothesis. We have shown that zinc ion (Zn2+) in secretory granules of pancreatic beta cells could act as a paracrine death effector in streptozotocin-induced diabetes. As Zn2+ has been reported to perturb glycolysis, we studied if pyruvate could inhibit Zn2+-mediated islet cell death in vitro and streptozotocin-induced diabetes in vivo by normalizing intracellular energy metabolism.Methods. Cell death was measured by quantitative viable cell staining and Hoechst/propidium iodide staining. ATP was measured by bioluminescence determination. Pyruvate was infused through the tail vein 1 h before streptozotocin administration. Beta-cell volume was measured by point counting of the insulin-containing cells.Results. Zn2+ induced classical necrosis on MIN6N8 insulinoma cells which was associated with a rapid decline of intracellular ATP levels. Pyruvate inhibited Zn2+-induced necrosis of insulinoma cells and depletion of intracellular ATP by Zn2+. Pyruvate did not inhibit other types of necrosis or apoptosis. Energy substrates such as oxaloacetate, alpha-ketoglutarate and succinic acid dimethylester also attenuated Zn2+-induced insulinoma cell death. Methylpyruvate that does not generate NAD(+) in the cytoplasm or alpha-ketoisocaproate that stimulates ATP generation exclusively in mitochondria also protected insulinoma cells from Zn2+-induced necrosis. Pyruvate infusion inhibited the development of diabetes by protecting beta-cell mass after streptozotocin administration.Conclusion/interpretation. These results indicate that pyruvate inhibits Zn2+-induced necrosis of beta cells in vitro by protecting intracellular ATP levels and also streptozotocin-induced diabetes in vivo where Zn2+ has been reported to act as a paracrine death effector.