Functional and molecular characterisation of lactic acid transport in bovine articular chondrocytes
Functional and molecular characterisation of lactic acid transport in bovine articular chondrocytes
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DOI：
10.1159/000066282
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发表时间：
2002-01-01
影响因子：
--
通讯作者：
Wilkins, R
中科院分区：
文献类型：
--
作者：
Meredith, D;Bell, P;Wilkins, R
控制软骨更新的软骨细胞由于组织的无血管性质而主要经历糖酵解代谢。这将导致高水平的乳酸产生，并且这种乳酸必须离开细胞以维持其正常的细胞内pH。然而，迄今为止，乳酸从软骨细胞中去除的机制尚未阐明。在本研究中，乳酸转运的特点是使用细胞内pH敏感的荧光染料BCECF测量细胞内pH值（pH值）。添加细胞外乳酸诱导了对α-氰基-4-羟基肉桂酸（α-CHC）和根皮素敏感的酸化，表明涉及单羧酸转运蛋白（MCT）家族的亚型。转运动力学研究结果与其他糖酵解细胞常见的MCT 4亚型（K-m 14.1 mM）一致。Western印迹证实，MCT 4是主要表达的同种型，尽管当通过RT-PCR测定细胞时，存在MCT 1和MCT 4转录物。通过对pH（i）的影响，这种转运蛋白的活性可能因此改变软骨周转。版权所有（C）2002 S. Karger AG，巴塞尔。
Chondrocytes, which control the turnover of cartilage, undergo predominantly glycolytic metabolism due to the avascular nature of the tissue. This will result in high levels of lactic acid production, and this lactic acid must leave the cells for their normal intracellular pH to be maintained. However to date the mechanism by which lactic acid is removed from the chondrocyteshas not been elucidated. In the present study lactic acid transport has been characterised using the intracellular pH-sensitive fluorimetric dye BCECF to measure intracellular pH (pH). Addition of extracellular lactic acid-induced an acidification which was sensitive to alpha-cyano-4-hydroxycinnamate (alpha-CHC) and phloretin indicating the involvement of isoform(s) of the monocarboxylate transporter (MCT) family. The results studies of transport kinetics were consistent with the MCT4 isoform (K-m 14.1 mM), common to other glycolytic cells. Western blotting confirmed that MCT4 was the predominantly expressed isoform, although both MCT1 and MCT4 transcripts were present when cells were assayed by RT-PCR. Through effects on pH(i), the activity of this transporter may therefore modify cartilage turnover. Copyright (C) 2002 S. Karger AG, Basel.