A load of mice to hypergravity causes AMPKα repression with liver injury, which is overcome by preconditioning loads via Nrf2.
An understanding of the effects of hypergravity on energy homeostasis is necessary in managing proper physiological countermeasures for aerospace missions. This study investigated whether a single or multiple load(s) of mice to hypergravity has an effect on molecules associated with energy metabolism. In the liver, AMPKα level and its signaling were repressed 6 h after a load to +9 Gz hypergravity for 1 h, and then gradually returned toward normal. AMPKα level was restored after 3 loads to +9 Gz, suggestive of preconditioning adaptation. In cDNA microarray analyses, 221 genes were differentially expressed by +9 Gz, and the down-regulated genes included Nrf2 targets. Nrf2 gene knockout abrogated the recovery of AMPKα elicited by 3 loads to +9 Gz, indicating that Nrf2 plays a role in the adaptive increase of AMPKα. In addition, +9 Gz stress decreased STAT3, FOXO1/3 and CREB levels, which was attenuated during the resting time. Similarly, apoptotic markers were enhanced in the liver, indicating that the liver may be vulnerable to hypergravity stress. Preconditioning loads prevented hepatocyte apoptosis. Overall, a load of mice to +9 Gz hypergravity causes AMPKα repression with liver injury, which may be overcome by multiple loads to hypergravity as mediated by Nrf2.
College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea.
Sang Gil
SG
Lee
College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea.
Chan Gyu
CG
Lee
College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea.
Hong Min
HM
Wu
Aerospace Medical Center, ROKAF, Cheong-ju, Korea.
Choong Sik
CS
Oh
Aerospace Medical Center, ROKAF, Cheong-ju, Korea.
So Won
SW
Chung
College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea.
Sang Geon
SG
Kim
D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D018471:Hypergravity; D008099:Liver / Q000293:injuries*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008930:Mitochondria, Liver / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism
D015415:Biomarkers; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; D014157:Transcription Factors; D055372:AMP-Activated Protein Kinases