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Remote Limb Ischemic Preconditioning: A Neuroprotective Technique in Rodents
Published on: June 2, 2015
Autophagy regulates endoplasmic reticulum stress in ischemic preconditioning
Rui Sheng1, Xiao-Qian Liu, Li-Sha Zhang
1Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Soochow University School of Medicine, Suzhou, China.
Autophagy
|February 25, 2012
Summary
Ischemic preconditioning (IPC) activates autophagy, a cellular process that reduces endoplasmic reticulum (ER) stress and protects neurons from ischemic injury. Inhibiting autophagy exacerbates ER stress and neuronal damage, while enhancing it offers neuroprotection.
Area of Science:
- Neuroscience
- Cellular Biology
- Pathophysiology
Background:
- Ischemic preconditioning (IPC) is known to protect against neuronal injury.
- Autophagy, a cellular degradation process, is implicated in the prosurvival role of IPC.
- The interplay between autophagy and endoplasmic reticulum (ER) stress in IPC remains to be fully elucidated.
Purpose of the Study:
- To investigate the relationship between autophagy and ER stress during ischemic preconditioning.
- To determine the role of autophagy activation in neuroprotection conferred by IPC.
- To assess the impact of modulating autophagy on ER stress markers and neuronal damage.
Main Methods:
- Primary cultured murine cortical neurons were subjected to oxygen-glucose deprivation (OGD) with or without IPC.
- Rats underwent IPC followed by permanent focal ischemia (PFI) using suture occlusion.
- Autophagy inhibitors (3-MA, bafilomycin A1), an ER stress inhibitor (Sal), and an autophagy enhancer (rapamycin) were used to modulate cellular pathways.
- Protein levels of autophagy markers (LC3-II, p62), ER stress markers (HSP70, HSP60, GRP78, CHOP), and apoptosis markers (caspase-12, caspase-3) were analyzed.
Main Results:
- IPC activated autophagy, evidenced by increased LC3-II and decreased p62 levels.
- IPC significantly reduced OGD-induced neuronal damage, an effect abolished by autophagy inhibitors.
- Autophagy inhibition exacerbated ER stress and increased apoptosis markers, while Sal treatment restored IPC's neuroprotection.
- Rapamycin pre-treatment reduced ER stress and ischemia-induced neuronal damage in both in vitro and in vivo models.
Conclusions:
- Pre-activation of autophagy by IPC enhances endogenous defense mechanisms against ischemic injury.
- IPC-induced autophagy upregulates molecular chaperones, thereby mitigating excessive ER stress during fatal ischemia.
- Targeting autophagy represents a potential therapeutic strategy for neuroprotection in ischemic stroke.
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