TY - JOUR
T1 - The Na+/H+ exchanger, NHE1, differentially regulates mitogen-activated protein kinase subfamilies after osmotic shrinkage in Ehrlich Lettre Ascites cells.
AU - Petersen, Stine Helene Falsig
AU - Rasmussen, Maria
AU - Darborg, Barbara Vasek
AU - Nylandsted, Jesper
AU - Hoffmann, Else Kay
N1 - Keywords: Animals; Carcinoma, Ehrlich Tumor; Cation Transport Proteins; Cell Line, Tumor; Cell Survival; Enzyme Activation; Enzyme Inhibitors; Humans; JNK Mitogen-Activated Protein Kinases; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Models, Biological; Osmotic Pressure; Sodium-Hydrogen Antiporter; p38 Mitogen-Activated Protein Kinases
PY - 2007
Y1 - 2007
N2 - Osmotic stress modulates mitogen activated protein kinase (MAPK) activities, leading to altered gene transcription and cell death/survival balance, however, the mechanisms involved are incompletely elucidated. Here, we show, using a combination of biochemical and molecular biology approaches, that three MAPKs exhibit unique interrelationships with the Na(+)/H(+) exchanger, NHE1, after osmotic cell shrinkage: Extracellular Signal Regulated Kinase (ERK1/2) is inhibited in an NHE1-dependent, pH(i)-independent manner, c-Jun N-terminal kinase (JNK1/2) is stimulated, in part through NHE1-mediated intracellular alkalinization, and p38 MAPK is activated in an NHE1-independent manner, and contributes to NHE1 activation and ERK inhibition. Shrinkage-induced ERK1/2 inhibition was attenuated in Ehrlich Lettre Ascites cells by NHE1 inhibitors (EIPA, cariporide) or removal of extracellular Na(+), and mimicked by human (h) NHE1 expression in cells lacking endogenous NHE1 activity. The effect of NHE1 on ERK1/2 was pH(i)-independent and upstream of MEK1/2. Shrinkage-activation of JNK1/2 was attenuated by EIPA, augmented by hNHE1 expression, and abolished in the presence of HCO(3)(-). Basal JNK activity was augmented at alkaline pH(i). Shrinkage-activation of p38 MAPK was NHE1-independent, and p38 MAPK inhibition (SB203580) attenuated NHE1 activation and ERK1/2 inhibition. Long-term shrinkage elicited caspase-3 activation and a loss of cell viability, which was augmented by ERK1/2 or JNK1/2 inhibition, and attenuated by p38 MAPK inhibition.
AB - Osmotic stress modulates mitogen activated protein kinase (MAPK) activities, leading to altered gene transcription and cell death/survival balance, however, the mechanisms involved are incompletely elucidated. Here, we show, using a combination of biochemical and molecular biology approaches, that three MAPKs exhibit unique interrelationships with the Na(+)/H(+) exchanger, NHE1, after osmotic cell shrinkage: Extracellular Signal Regulated Kinase (ERK1/2) is inhibited in an NHE1-dependent, pH(i)-independent manner, c-Jun N-terminal kinase (JNK1/2) is stimulated, in part through NHE1-mediated intracellular alkalinization, and p38 MAPK is activated in an NHE1-independent manner, and contributes to NHE1 activation and ERK inhibition. Shrinkage-induced ERK1/2 inhibition was attenuated in Ehrlich Lettre Ascites cells by NHE1 inhibitors (EIPA, cariporide) or removal of extracellular Na(+), and mimicked by human (h) NHE1 expression in cells lacking endogenous NHE1 activity. The effect of NHE1 on ERK1/2 was pH(i)-independent and upstream of MEK1/2. Shrinkage-activation of JNK1/2 was attenuated by EIPA, augmented by hNHE1 expression, and abolished in the presence of HCO(3)(-). Basal JNK activity was augmented at alkaline pH(i). Shrinkage-activation of p38 MAPK was NHE1-independent, and p38 MAPK inhibition (SB203580) attenuated NHE1 activation and ERK1/2 inhibition. Long-term shrinkage elicited caspase-3 activation and a loss of cell viability, which was augmented by ERK1/2 or JNK1/2 inhibition, and attenuated by p38 MAPK inhibition.
U2 - 10.1159/000110434
DO - 10.1159/000110434
M3 - Journal article
C2 - 17982256
SN - 1015-8987
VL - 20
SP - 735
EP - 750
JO - Cellular Physiology and Biochemistry
JF - Cellular Physiology and Biochemistry
IS - 6
ER -