Lactic acid produced from the cells is a potential cause of extra- and intracellular acidification. Due to scarce technical tools, lactic acid that leads to acidification could not be reduced and direct evidence of the relationship between metabolic lactate and apoptosis has not yet been elucidated. In this study, we designed a cellular pH regulation system in CHO cells by a reduction of lactate dehydrogenase (LDH) activity through LDH antisense mRNA expression. This inhibited lactate production and, therefore, acidification of the cytosol. Under HCO3- -buffered growth conditions, both the parent CHO cells and the engineered CHO ceils maintained their extracellular pH and intracellular pH fairly well. However, upon acidification of the cytosol, only the parent CHO cells underwent apoptosis under HCO3-free conditions. In fact, we observed a number of apoptosis-related events only in control cells, including mitochondrial dysfunction, cytochrome c release, and an increase in caspase-3 enzymatic activity.
|Number of pages
|Biochemical and biophysical research communications
|Published - 2001 Dec 21
Bibliographical noteFunding Information:
This work was supported by a grant from the Ministry of Science and Technology, Republic of Korea to I. Y. Kim (00-J-BP-01-B-62).
- Lactate dehydrogenase
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology