REGULATION OF CATION CONTENT AND CELL-VOLUME IN HEMOGLOBIN ERYTHROCYTES FROM PATIENTS WITH HOMOZYGOUS HEMOGLOBIN-C DISEASE
REGULATION OF CATION CONTENT AND CELL-VOLUME IN HEMOGLOBIN ERYTHROCYTES FROM PATIENTS WITH HOMOZYGOUS HEMOGLOBIN-C DISEASE
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DOI：
10.1172/jci111867
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发表时间：
1985-01-01
影响因子：
15.9
通讯作者：
TOSTESON, DC
中科院分区：
文献类型：
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作者：
BRUGNARA, C;KOPIN, AS;TOSTESON, DC
来自纯合子Hb C疾病患者的红细胞（CC细胞）比来自仅含有Hb A的正常受试者的红细胞（AA细胞）含有更少的K、Na和H2O。显然，CC细胞的K含量和体积的减少是由于K转运系统在这些细胞中而不是在AA细胞中的活性，该系统对哇巴因和布美他尼不敏感，并且通过增加细胞体积来刺激，并且依赖于内部pH（pHi）。当CC细胞的阳离子和H2O含量增加（通过用制霉菌素使膜暂时对阳离子可渗透），然后将细胞在含有140 mM NaCl和4 mM KCl的等渗培养基中孵育时，它们失去K并向原始体积收缩。哇巴因或布美他尼不抑制这种调节性K和体积减少。当CC细胞在低渗培养基中与哇巴因和布美他尼一起孵育时，它们也失去了K并向原始体积收缩。在对照AA细胞中未观察到这种行为。CC细胞的哇巴因和布美他尼抗性K流出是体积和pH依赖性的：CC细胞的K流出从5-6升至20-25 mmol/L细胞×。h时，通过增加细胞溶质含量（制霉菌素法）或暴露于低渗培养基来增加细胞体积。在CC细胞中，K流出对pHo的依赖性呈钟形，具有最大通量（20-25 mmol/L细胞× 10 - 15 ml）。h）在pH 6.8-7.0下。在pH7.4（1.2mmol/升细胞× 100 ml）时，来自对照细胞的K流出量最小。为了研究pH_i和pH_o对K流出的影响，用4，4“-二异硫氰基二苯乙烯-2，2”-二磺酸孵育CC细胞（150 μ M）和乙酰唑胺（1 mM）在不同pHi（6.7，7.3和7.8），并重新悬浮在培养基中具有不同的pH值（6.75，7.4和8）：K流出刺激降低pH值，但不依赖于pH值。哇巴因和布美他尼耐药的CC细胞钾外流不受某些钙激活钾渗透性抑制剂的抑制。血红蛋白C的一级结构的遗传决定的变化似乎直接或间接地导致这种修改K转运。一种可能的机制可能涉及C Hb和红细胞膜成分之间的静电相互作用。
Erythrocytes from patients with homozygous Hb C disease (CC cells) contain less K, Na and H2O than do erythrocytes from normal subjects that contain only Hb A (AA cells). Evidently, the reduced K content and volume of CC cells are due to the activity in these but not in AA cells of a K transport system that is: insensitive to ouabain and bumetanide, and stimulated by increased cell volume, and dependent on internal pH (pHi). When the cation and H2O content of CC cells was increased (by making the membrane temporarily permeable to cations with nystatin) and the cells were then incubated in an isotonic medium containing 140 mM NaCl and 4 mM KCl, they lost K and shrunk back toward the original volume. This regulatory K and volume decrease was not inhibited by ouabain or bumetanide. When CC cells were incubated in a hypotonic medium, with ouabain and bumetanide, they also lost K and shrunk toward the original volume. This behavior was not observed in control AA cells. The ouabain- and bumetanide-resistant K efflux from CC cells was volume and pH dependent: K efflux from CC cells rose from 5-6 to 20-25 mmol/liter of cells .times. h, when cell volume was increased by increasing cell solute content (nystatin method) or by exposure to hypotonic media. In CC cells, the dependence of K efflux on pHo had a bell shape, with a maximal flux (20-25 mmol/liter of cells .times. h) at pHo 6.8-7.0. The K efflux from control cells was minimal at pH 7.4 (1.2 mmol/liter of cells .times. h) and was slightly stimulated by both acid and alkaline pH. In order to study the effect of pHi and pHo on K efflux, CC cells were incubated with 4,4''-diisothiocyanostilbene-2,2''-disulfonic acid (150 .mu.M) and acetazolamide (1 mM) at different pHi (6.7, 7.3 and 7.8), and resuspended in media with different pHo (6.75, 7.4 and 8): K efflux was stimulated by reducing pHi but was independent of pHo. The ouabain- and bumetanide-resistant K efflux from CC cells was not inhibited by some inhibitors of the Ca2+-activated K permeability. The genetically determined change in the primary structure of Hb C directly or indirectly seems to cause this modification in K transport. One possible mechanism could involve an electrostatic interaction between C Hb and components of the erythrocyte membrane.