The Reck tumor suppressor protein alleviates tissue damage and promotes functional recovery after transient cerebral ischemia in mice

The extracellular matrix (ECM) is important for both structural integrity and functions of the brain. Matrix metalloproteinases (MMPs) play major roles in ECM-remodeling under both physiological and pathological conditions. Reversion-inducing cysteine-rich protein with Kazal motifs (Reck) is a membrane-anchored MMP-regulator implicated in coordinated regulation of pericellular proteolysis. Although patho-physiological importance of MMPs and another group of MMP-regulators, tissue inhibitor of metalloproteinases, in brain ischemia has been demonstrated, little is known about the role of Reck in this process. In this study, we found that Reck is up-regulated in hippocampus and penumbra of subventricular zone after transient cerebral ischemia in mice. Most of the Reck-positive cells found at day 2 after ischemia are positive for Nestin as well as Ki67 and localized to the CA2 region of the hippocampus. At day 7 after ischemia, the Reck-positive cells increased in number, extended processes, expressed the reactive astrocyte marker GFAP and the neuronal marker NF200, and were widely distributed in the hippocampus. In the mutant mice carrying single functional Reck allele (Reck+/-), tissue damage and cell death after cerebral ischemia were augmented, the recovery of long-term potentiation in the hippocampus was compromised, NR2C subunit of NMDA receptor was up-regulated, gelatinolytic activity of MMPs were up-regulated and laminin-immunoreactivity was reduced. Our data implicate Reck in protection of ECM/tissue integrity and promotion of functional recovery in the brain after transient cerebral ischemia.