Effect of acid/base balance on H-ATPase 31 kD subunit mRNA levels in collecting duct cells.
Effect of acid/base balance on H-ATPase 31 kD subunit mRNA levels in collecting duct cells.
复制标题
酸/碱平衡对集合管细胞中 H-ATPase 31 kD 亚基 mRNA 水平的影响。
DOI：
10.1038/ki.1995.431
复制
发表时间：
1995
影响因子：
19.6
通讯作者：
Náray-Fejes-Tóth,A
中科院分区：
文献类型：
--
作者：
Fejes-Tóth,G;Náray-Fejes-Tóth,A
酸碱平衡对集合管细胞H-ATP酶31 kD亚基mRNA水平的影响皮质集合管（CCD）通过调节HCO 3运输的方向和幅度来适应酸碱平衡的紊乱。参与这种适应的分子事件还不完全清楚，但似乎适应伴随着液泡H-ATP酶活性和细胞内分布的变化。本研究的目的是研究代谢性酸中毒和碱负荷对兔CCD细胞液泡H-ATP酶31 kD亚基mRNA表达的影响。两对家兔分别接受NH 4Cl负荷和NaHCO 3负荷16小时，尿pH值分别为5.53 ± 0.38和8.42 ± 0.10。通过免疫分离法分离CCD细胞，并通过定量RT-PCR从相同的cDNA样品中测定H-ATP酶31 kD亚基和β-肌动蛋白的mRNA水平。酸中毒组CCD细胞H-ATP酶mRNA水平显著高于碱中毒组（2.51 ± 1.3vs.0.65 ± 0.2; P < 0.05）。北方印迹法也观察到H-ATP酶31 kD亚基mRNA水平的相似差异。两组CCD细胞中β-actin mRNA水平相当。用荧光激活细胞分选法分离出α-ICC和β-ICC细胞及主细胞（PC），测定了H-ATP酶31 kD亚基mRNA在CCD三种细胞类型中的分布。α-ICC和β-ICC的表达水平相当，而PC含有非常低水平的H-ATP酶mRNA。在α-ICC和β-ICC中，31 kD H-ATP酶mRNA的表达在酸负荷组明显高于碱负荷组。这些结果表明，在兔CCD的酸/碱平衡的变化不仅调节液泡H-ATP酶的亚细胞分布，但也改变其表达，至少在mRNA水平上。
Effect of acid/base balance on H-ATPase 31 kD subunit mRNA levels in collecting duct cells. The cortical collecting duct (CCD) adapts to disturbances of acid/base balance by adjusting the direction and magnitude of its HCO3transport. The molecular events involved in this adaptation are incompletely understood, but it seems that adaptation is accompanied by changes in the activity and intracellular distribution of the vacuolar H-ATPase. The goal of this study was to examine the effects of metabolic acidosis and alkali load on the expression of the mRNA encoding the 31 kD subunit of the vacuolar H-ATPase in rabbit CCD cells. Pairs of rabbits received either a NH4Cl load or a NaHCO3load for 16 hours, resulting in a urinary pH of 5.53 ± 0.38 and 8.42 ± 0.10, respectively. CCD cells were isolated by immunodissection and mRNA levels of the H-ATPase 31 kD subunit and of β-actin were determined from the same cDNA samples by quantitative RT-PCR. H-ATPase mRNA levels were significantly higher in CCD cells from acidotic than alkali-loaded rabbits (2.51 ± 1.3 vs. 0.65 ± 0.2; P < 0.05). Similar differences in the H-ATPase 31 kD subunit mRNA levels were observed by Northern blotting. β-actin mRNA levels were comparable in CCD cells of the two groups. The distribution of the H-ATPase 31 kD subunit mRNA was determined among the three cell types of the CCD, that is in α- and β-intercalated cells (α-ICC and β-ICC) and principal cells (PC) isolated by fluorescence-activated cell sorting. The level of expression was comparable in α-ICCs and β-ICCs, whereas PCs contained very low levels of H-ATPase mRNA. In both α-ICC and β-ICC the levels of the 31 kD H-ATPase mRNA were significantly higher in acidotic than in alkaliloaded rabbits. These results indicate that in the rabbit CCD changes in acid/base balance not only regulate the subcellular distribution of the vacuolar H-ATPase but also alter its expression, at least at the mRNA level.