Suppression of Cl^- -ATPase activity in Alzheimer's disease brain

Cl^- - atp酶通过保持细胞内氯离子浓度低而抑制GABA的神经传递。我们之前报道了Cl^- - atp酶活性在阿尔茨海默病大脑中下降，低剂量淀粉样蛋白β(Aβ)抑制Cl^- - atp酶活性导致细胞内氯水平升高。在本研究中，我们研究了Aβ对易于从患者身上获得的淋巴细胞中Cl^- - atp酶活性的影响，以观察淋巴细胞中Cl^- - atp酶活性是否反映了大脑的活性。【材料与方法】以t细胞源性人白血病细胞系Jurkat、髓细胞源性人白血病细胞系HL-60和外周血淋巴细胞为实验对象，观察了Aβ对Cl - - - atp酶和Na-K atp酶活性及细胞活力的影响。细胞在含有10% FCS的RPMI1640中培养，分别添加或不添加a β 25-35 （1μM）或a β 1-42 (100 nM)，或20μM槲皮素作为PI4激酶抑制剂或0.05μM wartmannin作为PI3激酶抑制剂。[更多结果]白血病细胞系的膜组分显示Cl^- - atp酶和Na-K atp酶活性。在健康志愿者的外周血中，淋巴细胞和中性粒细胞中检测到Cl^- - atp酶活性，而红细胞中未检测到Cl^- - - atp酶活性，而na - k - atp酶活性在所有细胞中均观察到。a β 25-35 （1μM）或a β 1-42 （100 nM）显著降低淋巴细胞Cl^- - atp酶活性，并有降低na - k - atp酶活性的趋势。PI4激酶抑制剂20μM槲皮素显著降低了Cl^- - atp酶的活性，而PI3激酶抑制剂0.5μM瓦特曼宁对其活性无明显影响。【讨论】本研究表明，Cl^- - atp酶在人淋巴细胞中可检测到，并且在大脑中观察到的活性被Aβ和PI4激酶抑制剂抑制，这表明抑制作用涉及相同的机制，并且Aβ对大脑的影响可以反映在容易获得的淋巴细胞上。淋巴细胞Cl^- - atp酶的测定可能用于阿尔茨海默病的早期诊断。少

Cl^- -ATPase enables the inhibitory neurotransmission by GABA by keeping the intracellular chloride concentration low. We previously reported that Cl^- -ATPase activity decreased in Alzheimer's disease brains and that low dose amyloid β(Aβ) inhibited Cl^- -ATPase activity leading to the elevation of intracellular chloride levels. In the present study, we investigated the effects of Aβ on Cl^- -ATPase activity in lymphocytes which are easily obtained from patients to see if the Cl^- -ATPase activity in lymphocytes reflects that of brains.[Materials and Methods]Effects Aβ on Cl^- -ATPase and Na-K ATPase activities, and on cell viability were examined in T-cell derived human leulemic cell line (Jurkat), myeloid cell derived human leukemic cell line (HL-60) and human peripheral lymphocytes. The cells were cultured in RPMI1640 containing 10% FCS with or without Aβ 25-35 (1μM) or Aβ 1-42 (100 nM), or 20μM quercetin as a PI4 kinase inhibitor or 0.05μM wartmannin as a PI3 kinase inhibitor.[Res … More ults]Membrane fractions from leukemic cell lines showed Cl^- -ATPase and Na-K ATPase activities. In peripheral blood from healthy volunteers, Cl^- -ATPase activity was detected in lymphocytes and neutrophils but not in red blood cells, while Na-K-ATPase activity was observed in all cells. Aβ 25-35 (1μM) or Aβ 1-42 (100 nM) significantly reduced Cl^- -ATPase in lymphocytes and had a tendency to decrease Na-K-ATPase activity. PI4 kinase inhibitor, 20μM quercetin significantly reduced Cl^- -ATPase, while PI3 kinase inhibitor, 0.5μM wartmannin did not alter the activity.[Discussion]The present study showed that Cl^- -ATPase was detectable in human lymphocytes and the activity was inhibited by Aβ and PI4 kinase inhibitor as observed in brains, suggesting that the same mechanisms are involved for the inhibition and that the effects of Aβ on brains can be reflected in those on lymphocytes which are easily obtainable. Measurement of Cl^- -ATPase in lymphocytes may possibly be used for early diagnosis of Alzheimer's disease. Less