Elabela-APLNR Inhibits Cerebral Ischemia/Reperfusion Injury Through AMPK/SIRT3/PGC-1α and Akt/Nrf2 Pathways

Abstract Inhibiting mitochondrial dysfunction and oxidative stress has benefits effects for the treatment of cerebral ischemia/reperfusion injury (CI/RI). Elabela/APLENR system had showed to be protective against ischemia/reperfusion induced injury in other tissue. However, whether Elabela had protective effects against CI/RI and its possible mechanisms were largely unknown. This study was designed to evaluate the effects of Elabela 32 (ELA32) against CI/RI. In vivo, behavioral test, infarct size and brain edema were evaluated on rats middle cerebral artery occlusion/reperfusion (MCAO/R) model after treated by ELA32. In vitro, HT22 cells were subjected to glucose deprivation/reperfusion (OGD/R) and treated with ELA32 in presence of SIRT3-siRNA, or AMPK-siRNA, or Nrf2-siRNA. Cell viability, cell apoptosis, ROS and ATP levels, mitochondrial related proteins and oxidative related cytokines were measured by relative methods.As the results showed, neurological scores, infarct size, brain edema and injury cytokines were improved by ELA32 treatment in rats. Subsequently, we found that ELA32 inhibited cell apoptosis, mitochondrial dysfunction, and oxidative stress in a dose dependent manner in brain and HT22 cell. Western blotting results showed that ELA32 induced the deacetylation and phosphorylation of PGC-1α, the expression of Nrf2, SIRT3 and APLNR, and the phosphorylation of AMPK and Akt. Further, the crosstalk relationship between APLNR, SIRT3, AMPK, PGC-1α, Akt and Nrf2 were verified by the specific targeted siRNA transfection. The same effects on APLNR related pathways were also observed in rats.In conclusion, ELA32 improved mitochondrial dysfunction and oxidative stress through regulating APLNR mediated AMPK/SIRT3/PGC-1α pathway and Akt/Nrf2 pathway. These results indicated that ELA32/APLNR system plays some role in central nervous system, and more studies should be performed to confirm these effects.

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Neuroprotection of chromobox 7 knockout in the mouse after cerebral ischemia-reperfusion injury via nuclear factor E2-related factor 2/hemeoxygenase-1 signaling pathway

Human & Experimental Toxicology ◽

10.1177/09603271211036122 ◽

2021 ◽

pp. 096032712110361

Author(s):

Hai-Tao Zhang ◽

Xi-Zeng Wang ◽

Qing-Mei Zhang ◽

Han Zhao

Keyword(s):

Oxidative Stress ◽

Cerebral Ischemia ◽

Infarct Size ◽

Water Content ◽

Cell Apoptosis ◽

Ischemia Reperfusion ◽

Related Factor ◽

Nuclear Factor ◽

Cerebral Ischemia Reperfusion ◽

And Oxidative Stress

Objective To explore the mechanism of chromobox 7 (CBX7)-mediated nuclear factor E2-related factor 2 (Nrf2)/hemeoxygenase-1 (HO-1) signaling pathway in the cerebral ischemia/reperfusion (I/R) injury. Methods The experimental wild-type (WT) and CBX7-/- mice were used to establish cerebral I/R models using the middle cerebral artery occlusion (MCAO) surgery to determine CBX7 levels at different time points after MCAO injury. For all mice, neurological behavior, infarct size, water content, and oxidative stress–related indicators were determined, and transferase (TdT)-mediated dUTP-biotin nick-end labeling (terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL)) staining method was employed to observe cell apoptosis, while Western blot to measure the expression of CBX7 and Nrf/HO-1 pathway-related proteins. Results At 6 h, 12 h, 24 h, 3 days, and 7 days after mice with MCAO, CBX7 expression was gradually up-regulated and the peak level was reached at 24 h. Mice in the WT + MCAO group had increased infarct size, with significant increases in the modified neurological severity scores and water content in the brain, as well as the quantity of TUNEL-positive cells. For the oxidative stress-indicators, an increase was seen in the content of MDA (malondial dehyde), but the activity of SOD (superoxide dismutase) and content of GSH-PX (glutathione peroxidase) and CAT (catalase) were decreased; meanwhile, the protein expression of CBX7, HO-1, and nuclear Nrf2 was up-regulated, while the cytoplasmic Nrf2 was down-regulated. Moreover, CBX7 knockout attenuated I/R injury in mice. Conclusion Knockout of CBX7 may protect mice from cerebral I/R injury by reducing cell apoptosis and oxidative stress, possibly via activating the Nrf2/HO-1 pathway.

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