TY - JOUR
T1 - JNK1 protects against glucolipotoxicity-mediated beta-cell apoptosis
AU - Prause, Michala
AU - Christensen, Dan Ploug
AU - Billestrup, Nils
AU - Mandrup-Poulsen, Thomas
PY - 2014
Y1 - 2014
N2 - Pancreatic β-cell dysfunction is central to type 2 diabetes pathogenesis. Prolonged elevated levels of circulating free-fatty acids and hyperglycemia, also termed glucolipotoxicity, mediate β-cell dysfunction and apoptosis associated with increased c-Jun N-terminal Kinase (JNK) activity. Endoplasmic reticulum (ER) and oxidative stress are elicited by palmitate and high glucose concentrations further potentiating JNK activity. Our aim was to determine the role of the JNK subtypes JNK1, JNK2 and JNK3 in palmitate and high glucose-induced β-cell apoptosis. We established insulin-producing INS1 cell lines stably expressing JNK subtype specific shRNAs to understand the differential roles of the individual JNK isoforms. JNK activity was increased after 3 h of palmitate and high glucose exposure associated with increased expression of ER and mitochondrial stress markers. JNK1 shRNA expressing INS1 cells showed increased apoptosis and cleaved caspase 9 and 3 compared to non-sense shRNA expressing control INS1 cells when exposed to palmitate and high glucose associated with increased CHOP expression, ROS formation and Puma mRNA expression. JNK2 shRNA expressing INS1 cells did not affect palmitate and high glucose induced apoptosis or ER stress markers, but increased Puma mRNA expression compared to non-sense shRNA expressing INS1 cells. Finally, JNK3 shRNA expressing INS1 cells did not induce apoptosis compared to non-sense shRNA expressing INS1 cells when exposed to palmitate and high glucose but showed increased caspase 9 and 3 cleavage associated with increased DP5 and Puma mRNA expression. These data suggest that JNK1 protects against palmitate and high glucose-induced β-cell apoptosis associated with reduced ER and mitochondrial stress.
AB - Pancreatic β-cell dysfunction is central to type 2 diabetes pathogenesis. Prolonged elevated levels of circulating free-fatty acids and hyperglycemia, also termed glucolipotoxicity, mediate β-cell dysfunction and apoptosis associated with increased c-Jun N-terminal Kinase (JNK) activity. Endoplasmic reticulum (ER) and oxidative stress are elicited by palmitate and high glucose concentrations further potentiating JNK activity. Our aim was to determine the role of the JNK subtypes JNK1, JNK2 and JNK3 in palmitate and high glucose-induced β-cell apoptosis. We established insulin-producing INS1 cell lines stably expressing JNK subtype specific shRNAs to understand the differential roles of the individual JNK isoforms. JNK activity was increased after 3 h of palmitate and high glucose exposure associated with increased expression of ER and mitochondrial stress markers. JNK1 shRNA expressing INS1 cells showed increased apoptosis and cleaved caspase 9 and 3 compared to non-sense shRNA expressing control INS1 cells when exposed to palmitate and high glucose associated with increased CHOP expression, ROS formation and Puma mRNA expression. JNK2 shRNA expressing INS1 cells did not affect palmitate and high glucose induced apoptosis or ER stress markers, but increased Puma mRNA expression compared to non-sense shRNA expressing INS1 cells. Finally, JNK3 shRNA expressing INS1 cells did not induce apoptosis compared to non-sense shRNA expressing INS1 cells when exposed to palmitate and high glucose but showed increased caspase 9 and 3 cleavage associated with increased DP5 and Puma mRNA expression. These data suggest that JNK1 protects against palmitate and high glucose-induced β-cell apoptosis associated with reduced ER and mitochondrial stress.
KW - Animals
KW - Apoptosis/drug effects
KW - Apoptosis Regulatory Proteins/genetics
KW - Caspase 3/genetics
KW - Caspase 9/genetics
KW - Cell Line
KW - Diabetes Mellitus, Type 2/enzymology
KW - Gene Expression Regulation
KW - Glucose/pharmacology
KW - Humans
KW - Insulin-Secreting Cells/drug effects
KW - Mitogen-Activated Protein Kinase 10/antagonists & inhibitors
KW - Mitogen-Activated Protein Kinase 8/antagonists & inhibitors
KW - Mitogen-Activated Protein Kinase 9/antagonists & inhibitors
KW - Palmitic Acid/pharmacology
KW - RNA, Messenger/antagonists & inhibitors
KW - RNA, Small Interfering/genetics
KW - Rats
KW - Signal Transduction
KW - Transcription Factor CHOP/genetics
U2 - 10.1371/journal.pone.0087067
DO - 10.1371/journal.pone.0087067
M3 - Journal article
C2 - 24475223
SN - 1932-6203
VL - 9
SP - e87067
JO - PLoS One
JF - PLoS One
IS - 1
ER -