Differential expression of Na+-Cl- cotransporter and Na+-K+-Cl- cotransporter 2 in the distal nephrons of euryhaline and seawater pufferfishes
Differential expression of Na+-Cl- cotransporter and Na+-K+-Cl- cotransporter 2 in the distal nephrons of euryhaline and seawater pufferfishes
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DOI：
10.1152/ajpregu.00725.2009
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发表时间：
2011-02-01
影响因子：
2.8
通讯作者：
Hirose, Shigehisa
中科院分区：
文献类型：
--
作者：
Kato, Akira;Muro, Takayuki;Hirose, Shigehisa
Kato A，Muro T，Kimura Y，Li S，Islam Z，Ogoshi M，Doi H，Hirose S. Na ~+-Cl ~-协同转运体和Na ~+-K ~+-Cl ~-协同转运体2在广盐性和海水性河豚鱼远端肾单位中的差异表达Am J Physiol Regul Integr Comp Physiol 300：R284-R297，2011年。首次发表于2010年11月17日; doi：10.1152/ajpregu.00725.2009.- NaCl在远端肾单位重吸收的过程，使淡水鱼排泄低渗尿和海水鱼排泄尿液含有高浓度的二价离子，相关的转运，但是，尚未确定。在哺乳动物远端肾单位中，NaCl的吸收由粗升支中的Na+-K+-Cl-共转运蛋白2（NKCC 2，Slc 12 a1）、远端曲小管中的Na+-Cl-共转运蛋白（NCC，Slc 12 a3）和集合管中的上皮钠通道（ENaC）介导。在这项研究中，我们比较了这些蛋白质在广盐性和海水河豚鱼肾脏的表达谱。挖掘河豚基因组鉴定出一个NKCC 2基因和一个NCC基因，但没有ENaC基因。RT-PCR和原位杂交分析表明，NKCC 2在广盐性河豚鱼（mefugu，Takifugu obscurus）的远端小管中高表达，NCC在集合管中高表达。另一方面，缺乏远端小管的海水河豚（torafugu，Takifugu rubripes）的肾脏表达极低水平的NCC，而在集合管中，表达高水平的NKCC 2。海河豚适应海水导致NCC表达降低2.7倍，而NKCC 2表达没有受到明显影响。此外，还观察到NCC从集合管顶面内化。这些结果表明，NaCl重吸收在远端肾单位的鱼肾介导的NCC和NKCC 2在淡水和NKCC 2在海水中。
Kato A, Muro T, Kimura Y, Li S, Islam Z, Ogoshi M, Doi H, Hirose S. Differential expression of Na+-Cl- cotransporter and Na+-K+-Cl- cotransporter 2 in the distal nephrons of euryhaline and seawater pufferfishes. Am J Physiol Regul Integr Comp Physiol 300: R284-R297, 2011. First published November 17, 2010; doi: 10.1152/ajpregu.00725.2009.-The process of NaCl reabsorption in the distal nephron allows freshwater fishes to excrete hypotonic urine and seawater fishes to excrete urine containing high concentrations of divalent ions; the relevant transporters, however, have not yet been identified. In the mammalian distal nephron, NaCl absorption is mediated by Na+-K+-Cl- cotransporter 2 (NKCC2, Slc12a1) in the thick ascending limb, Na+-Cl- cotransporter (NCC, Slc12a3) in the distal convoluted tubule, and epithelial sodium channel (ENaC) in the collecting duct. In this study, we compared the expression profiles of these proteins in the kidneys of euryhaline and seawater pufferfishes. Mining the fugu genome identified one NKCC2 gene and one NCC gene, but no ENaC gene. RT-PCR and in situ hybridization analyses demonstrated that NKCC2 was highly expressed in the distal tubules and NCC was highly expressed in the collecting ducts of euryhaline pufferfish (mefugu, Takifugu obscurus). On the other hand, the kidney of seawater pufferfish (torafugu, Takifugu rubripes), which lacked distal tubules, expressed very low levels of NCC, and, in the collecting ducts, high levels of NKCC2. Acclimation of mefugu to seawater resulted in a 2.7X decrease in NCC expression, whereas NKCC2 expression was not markedly affected. Additionally, internalization of NCC from the apical surface of the collecting ducts was observed. These results suggest that NaCl reabsorption in the distal nephron of the fish kidney is mediated by NCC and NKCC2 in freshwater and by NKCC2 in seawater.