The 70 kDa heat shock protein suppresses matrix metalloproteinases in astrocytes

The 70 kDa heat shock protein (Hsp70) is synthesized in response to a variety of stresses, including ischemia, and is thought to act as a molecular chaperone to prevent protein denaturation and facilitate protein folding. Matrix metalloproteinases (MMPs), a family of serine proteases, are also upregulated by ischemia and are thought to promote cell death and tissue injury. We examined the influence of Hsp70 on expression and activity of MMPs. Astrocyte cultures were prepared from neonatal mice and transfected with retroviral vectors containing hsp70 or lacZ or mock infected, then exposed to oxygen-glucose deprivation followed by reperfusion. Zymograms and Western blots showed that Hsp70 over-expression suppressed MMP-2 and MMP-9. These findings suggest that Hsp70 may protect by regulating MMPs.