Expression of MAK-V/Hunk in renal distal tubules and its possible involvement in proliferative suppression
Expression of MAK-V/Hunk in renal distal tubules and its possible involvement in proliferative suppression
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DOI：
10.1152/ajprenal.00451.2006
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发表时间：
2007-05-01
影响因子：
4.2
通讯作者：
Umemura, Satoshi
中科院分区：
文献类型：
--
作者：
Sakai, Masashi;Tamura, Kouichi;Umemura, Satoshi
MAK-V/Hunk是一种snf1相关的丝氨酸/苏氨酸激酶，在乳腺和中枢神经系统中高度表达。在本研究中，我们发现MAK-V/Hunk从胚胎期到成体期在肾脏的厚升肢和远曲小管（DCT）中大量特异性表达。我们证明，与正常盐饮食相比，饮食盐消耗显著提高肾脏makv /Hunk mRNA水平。为了分析这种激酶可能的肾细胞功能，我们使用小鼠远曲小管（mDCT）细胞。逆转录聚合酶链反应和Western blot分析结果显示，MAK-V/Hunk在mDCT细胞中内源性表达。通过腺病毒基因转移过表达MAK-V/Hunk可显著抑制ANG ii诱导的c-fos基因转录的刺激，抑制ANG ii介导的将生长因子β转化到培养基中的增加。这种现象伴随着ANG ii诱导的BrdU掺入活化的抑制。另一方面，siRNA敲低MAK-V/Hunk可激活ANG ii诱导的c-fos基因表达。在MAK-V/Hunk和AT(1)受体连续染色的切片中，MAK-V/Hunk免疫阳性的远端小管表达AT(1)受体。这是关于MAK-V/Hunk在肾小管细胞内定位及其细胞功能的首次报道。
MAK-V/Hunk is an SNF1-related serine/threonine kinase which was previously shown to be highly expressed in the mammary gland and central nervous system. In this study, we found MAK-V/Hunk is abundantly and specifically expressed in the thick ascending limbs and distal convoluted tubules (DCT) of the kidney from the embryonic stage to the adult stage. We demonstrated that dietary salt depletion significantly enhances renal MAK-V/Hunk mRNA levels compared with a normal-salt diet. To analyze the possible renal cellular function of this kinase, we employed mouse distal convoluted tubule (mDCT) cells. The results of reverse transcriptase-polymerase chain reaction and Western blot analysis revealed that MAK-V/Hunk is expressed endogenously in mDCT cells. Overexpression of MAK-V/Hunk by adenoviral gene transfer significantly inhibited the ANG II-induced stimulation of c-fos gene transcription and suppressed the ANG II-mediated increases in transforming growth factor-beta production into the medium. This phenomenon was accompanied by inhibition of ANG II-induced activation of BrdU incorporation. On the other hand, the MAK-V/Hunk knockdown by siRNA activated the ANG II-induced c-fos gene expression. In the consecutive sections stained for MAK-V/Hunk and AT(1) receptor, MAK-V/Hunk-immunopositive distal tubules expressed the AT(1) receptor. This is the first report on the intrarenal localization of MAK-V/Hunk and its cellular function in renal tubular cells.