EF1A1/HSC70 Cooperatively Suppress Brain Endothelial Cell Apoptosis via Regulating JNK Activity

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• Eukaryotic elongation factor 1 alpha 1 (eEF1A1) is a newly identified target for protecting against brain ischemia injury.
• The precise mechanism underlying eEF1A1's protective role in brain ischemia remains largely unknown.

Purpose of the Study:

• To identify downstream cellular protein interactions of eEF1A1.
• To elucidate the mechanism of eEF1A1 in brain ischemia protection.

Main Methods:

• Co-immunoprecipitation and mass spectrometry were used to identify proteins interacting with eEF1A1 in bEnd3 cells.
• HSC70 was identified as a binding protein of eEF1A1.
• Knockdown studies and apoptosis assays (Annexin V-FITC/PI staining) were performed.
• Western blotting was used to assess protein expression levels, including phosphorylated JNK, c-JUN, cleaved caspase-9, and cleaved caspase-3.

Main Results:

• Heat shock cognate 70 kDa protein (HSC70) was identified as a binding partner of eEF1A1.
• Knockdown of either eEF1A1 or HSC70 exacerbated oxygen-glucose deprivation (OGD)-induced apoptosis in brain vascular endothelial cells.
• Knockdown of eEF1A1 or HSC70 led to increased expression of phosphorylated JNK, phosphorylated c-JUN, cleaved caspase-9, and cleaved caspase-3.
• The observed increases in apoptosis markers were reversed by a JNK inhibitor.

Conclusions:

• eEF1A1 and HSC70 interact as chaperones in brain vascular endothelial cells.
• This interaction plays a protective role in ischemic stroke.
• The protective mechanism involves the inhibition of JNK signaling pathway activation.