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Hsp70 overexpression sequesters AIF and reduces neonatal hypoxic/ischemic brain injury
Yasuhiko Matsumori1, Shwuhuey M Hong, Koji Aoyama
1Department of Neurological Surgery, University of California at San Francisco 94121, USA.
Summary
Overexpressing heat shock protein (Hsp) 70 protects neonatal brains from hypoxic-ischemic injury. Hsp70 interacts with apoptosis-inducing factor (AIF), reducing its nuclear translocation and subsequent cell death.
Area of Science:
- Neuroscience
- Cellular Biology
- Biochemistry
Background:
- Neonatal hypoxic-ischemic (H/I) brain injury involves multiple cell death pathways, including apoptosis.
- Heat shock protein (Hsp) 70 is an antiapoptotic protein with potential protective roles.
Purpose of the Study:
- To investigate the neuroprotective effects of Hsp70 overexpression in a neonatal H/I brain injury model.
- To elucidate the molecular pathways involved in Hsp70-mediated protection.
Main Methods:
- Utilized transgenic mice overexpressing Hsp70 and wild-type littermates subjected to H/I injury.
- Analyzed cell death markers, mitochondrial protein translocation (cytochrome c, Smac/DIABLO, AIF), and protein interactions using Western blot and coimmunoprecipitation.
Main Results:
- Hsp70 overexpression significantly reduced H/I-induced neuroinflammation and brain injury in neonatal mice.
- Reduced translocation of cytochrome c from mitochondria to cytosol was observed in Hsp70 transgenic mice.
- Increased binding of Hsp70 to apoptosis-inducing factor (AIF) was detected, correlating with reduced nuclear AIF translocation.
Conclusions:
- Hsp70 overexpression confers significant neuroprotection against H/I injury in the neonatal brain.
- Hsp70-mediated protection involves inhibiting mitochondrial apoptotic pathways and modulating AIF translocation.
- The interaction between Hsp70 and AIF is a key mechanism in reducing H/I-induced neuronal cell death.