Unconjugated
Ubiquitin C-terminal hydrolase L1 (UCH-L1) is abundantly expressed in the brain and is critical for the normal function of synapses. cAMP response element binding protein (CREB) is a transcription factor which initiates the expression of proteins that related to the regulation of synaptic plasticity and memory function. Studies have shown that UCH-L1 can influence the expression and activity of CREB, but the underlying mechanisms remain unclear. In this study, we used UCH-L1 inhibitor LDN to treat mice hippocampal slices and found that UCH-L1 inhibition caused the dephosphorylation of CREB at Ser133 site. Meanwhile, hyperphosphorylation of microtubule-associated protein tau; increased expression of synaptic protein components of PSD-95 and synapsin-1, and decreased activity of tyrosine kinase Fyn were observed after UCH-L1 inhibition. Moreover, all these alternations have an influence on the normal function of N-methyl-D-aspartate (NMDA) receptor NR2B subunit which is likely to result in the dephosphorylation of CREB. We also found that LDN treatment mediated protein kinase A (PKA) deactivation was involved in the dephosphorylation of CREB. Thus, our study introduces a novel possible mechanism for elaborating the effects of UCH-L1 inhibition on the CREB activity and the implicated signaling pathways.
BACKGROUND:
Dementia is the most prevalent neurological disease in aged people. Chronic cerebral hypoperfusion (CCH) is one of the causes of vascular dementia (VaD) and is also an etiological factor for Alzheimer's disease (AD). However, effective therapy for those two diseases is still missing. Resveratrol is a polyphenol produced by plants that have multiple biological functions, such as increased life span and delay in the onset of diseases associated with aging. It is known supplement with resveratrol could exert neuroprotection against multiple injury factors induced neuronal death and degeneration, as well as the cognitive decline of CCH rat model.
METHODS:
The morris water maze was used to evaluate the learning and memory, electrophysiological recording was used to detect the synaptic plasticity, the Golgi staining was used to examine the change of dendritic spines, the western blot was used to detect the proteins levels.
RESULTS:
We reported that resveratrol pretreatment effectively restore the synaptic plasticity in CCH rats both functional and structural. We also found that the PKA-CREB activation may be a major player in resveratrol-mediated neuroprotection in CCH model.
CONCLUSIONS:
Our data provide the mechanistic evidence for the neuroprotective effects of resveratrol in vascular dementia.
Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.