Experience-dependent cortical plasticity declines with age. At the molecular level, experience-dependent proteolytic activity of @entity35311 ( @entity35311 ) becomes restricted in the adult brain if @entity19 are raised in standard cages. Understanding the mechanism for the loss of permissive proteolytic activity is therefore a key link for improving function in adult brains. Using the @entity19 primary visual cortex (V1) as a model, we demonstrate that @entity35311 activity in V1 can be unmasked following 4 d of monocular deprivation when the @entity19 older than 2 months are raised in standard cages by the genetic removal of @entity68338 , a negative regulator of adult plasticity. This was also associated with the reduction of stubby and thin spine density and enhancement of ocular dominance shift in adult V1 of @entity68338 knock-out (KO) @entity19 . These structural and functional changes were @entity35311 -dependent because genetic removal of @entity35311 in @entity68338 KO @entity19 can block the monocular deprivation-dependent reduction of dendritic spine density, whereas both genetic and adult specific inhibition of @entity35311 activity can ablate the ocular dominance shift in @entity68338 KO @entity19 . Our work demonstrates that the adult brain has an intrinsic potential for experience-dependent elevation of proteolytic activity to express juvenile-like structural and functional changes but is effectively limited by @entity68338 if @entity19 are raised in standard cages. Insights into the @entity68338 - @entity35311 plasticity mechanism may provide novel therapeutic targets for adult @entity75 . SIGNIFICANCE STATEMENT: Experience-dependent proteolytic activity of @entity35311 ( @entity35311 ) becomes restricted in the adult brain in correlation with the decline in cortical plasticity when @entity19 are raised in standard cages. We demonstrated that removal of @entity68338 , one of negative regulators of plasticity, unmasks experience-dependent @entity35311 elevation in visual cortex of adult @entity19 reared in standard cages. This proteolytic elevation facilitated dendritic spine reduction and ocular dominance plasticity in adult visual cortex. This is the first demonstration of adult brain to retain the intrinsic capacity to elevate @entity35311 in an experience-dependent manner but is effectively limited by @entity68338 . @entity35311 - @entity68338 may potentially be a new candidate mechanism for interventions that were shown to activate plasticity in adult brain.

Unmasking Proteolytic Activity for Adult Visual Cortex Plasticity by the Removal of XXXX .

@entity35311 :: ('18791(Tax:10090)', 'Gene') :: ['tPA', 'tissue plasminogen activator'] @entity68338 :: ('23936(Tax:10090)', 'Gene') :: ['Lynx1'] @entity19 :: ('10090', 'Species') :: ['mice', 'mouse'] @entity75 :: ('MESH:D001927', 'Disease') :: ['brain disorders']
@entity68338 :: (23936(Tax:10090),Gene) :: ['Lynx1']
