ABSTRACT
RTP801/REDD1 is a stress-regulated protein whose upregulation is necessary and sufficient to trigger neuronal death in in vitro and in vivo models of Parkinson’s and Huntington’s diseases and is up regulated in compromised neurons in human postmortem brains of both neurodegenerative disorders. Indeed, in both Parkinson’s and Huntington’s disease mouse models, RTP801 knockdown alleviates motor-learning deficits.
Here, we investigated the physiological role of RTP801 in neuronal plasticity. RTP801 is found in rat, mouse and human synapses. The absence of RTP801 enhanced excitatory synaptic transmission in both neuronal cultures and brain slices from RTP801 knock-out (KO) mice. Indeed, RTP801 KO mice showed improved motor learning, which correlated with lower spine density but increased basal filopodia and mushroom spines in the motor cortex layer V. This paralleled with higher levels of synaptosomal GluA1 and TrkB receptors in homogenates derived from KO mice motor cortex, proteins that are associated with synaptic strengthening. Altogether, these results indicate that RTP801 has an important role modulating neuronal plasticity in motor learning.
ABBREVIATIONS
- (AD)
- Alzheimer’s disease;
- (HD)
- Huntington’s disease;
- (KO)
- knock out;
- (mTOR)
- mechanistic target of rapamycin;
- (LV)
- primary motor cortex (M1), motor cortex layer V;
- (mhtt)
- mutant huntingtin;
- (MEAs)
- microelectrode arrays;
- (mEPSC)
- miniature excitatory postsynaptic currents;
- (PD)
- Parkinson’s disease;
- (iPSC)
- induced pluripotent stem cells;
- (PSD)
- postsynaptic density;
- (TEM)
- transmission electron microscopy;
- (TSC1/2)
- tuberous sclerosis complex;
- (SNpc)
- substantia nigra pars compacta;
- (WT)
- wild type.