Acidic conditions ameliorate both adenosine triphosphate depletion and the development of hyperpermeability in cultured Caco-2BBe enterocytic monolayers subjected to metabolic inhibition.
Acidic conditions ameliorate both adenosine triphosphate depletion and the development of hyperpermeability in cultured Caco-2BBe enterocytic monolayers subjected to metabolic inhibition.
复制标题
酸性条件可改善三磷酸腺苷的消耗和培养的受到代谢抑制的 Caco-2BBe 肠细胞单层细胞通透性过高的发展。
DOI：
10.1016/s0039-6060(97)90056-8
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发表时间：
1997
期刊：
影响因子：
3.8
通讯作者：
Fink,MP
中科院分区：
文献类型：
--
作者：
Unno,N;Menconi,MJ;Smith,M;Hagen,SJ;Brown,DA;Aguirre,DE;Fink,MP
BackgroundWe recently reported that moderate degrees of adenosine triphosphate (ATP) depletion induced by chronic glycolytic inhibition or hypoxia increase the permeability of Caco-2BBeenterocytic monolayers. Interestingly, the development of lactic acidosis induced by anaerobic glycolysis ameliorates the development of hyperpermeability caused by chronic ATP depletion. We sought to further elucidate the mechanism(s) responsible for the apparent protection against epithelial hyperpermeability afforded by mild acidosis under conditions of metabolic inhibition.MethodsCaco-2BBemonolayers growing on permeable supports in bicameral chambers were incubated with 2-deoxyglucose (2DOG) in a glucose-free (Glu-) environment to inhibit glycolysis. Permeability was determined by measuring the transepithelial flux of fluorescein sulfonic acid. Concentrations of intracellular calcium [Ca2+]iwere determined fluorometrically by using fura-2.ResultsWhen extracellular pH (pH0) was maintained at 7.4 or 5.5, incubation of monolayers for 24 hours with Glu-/2DOG increased permeability and depleted intracellular ATP levels. However, keeping pH0at 7.0 to 6.0 ameliorated both the development of hyperpermeability and the depletion of ATP induced by Glu-/2DOG. These protective effects were observed under acidic conditions created either by addition to the medium of HCl or by incubation under an atmosphere containing 20% CO2. Incubation with Glu-/2DOG caused bulging of the apical membranes of cells (electron microscopy) and derangements in the perijunctional distribution of actin (fluorescence microscopy); however, these structural changes were ameliorated by mild acidosis. Acute chemical hypoxia at pH07.4 induced by Glu-/2DOG plus antimycin A decreased cellular ATP levels and elevated [Ca2+]i. Lowering pH0to 6.8 ameliorated both the depletion of ATP and the increase in [Ca2+]iinduced by Glu-/2DOG + antimycin A.ConclusionsModerate decreases in pH ameliorate the hyperpermeability induced by metabolic inhibition, possibly by diminishing ATP depletion and blunting increases in [Ca2+]i.
