Inhibitory designer receptors aggravate memory loss in a mouse model of down syndrome

Neurobiology of Disease

Aurélie Ledreux¹  Gary Aston-Jones²  Daniel Paredes³  Eric D. Hamlett⁴  Anah Gilmore⁵  Elena M. Vazey⁵  Ann-Charlotte E. Granholm⁵  Heather A. Boger⁶ 

[1] Corresponding author at: Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 173 Ashley Avenue MSC 908, Charleston, SC 29425, USA.;Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA;Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA;Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29425, USA;Knoebel Institute for Healthy Aging, University of Denver, Denver, CO 80208, USA;Rutgers Brain Health Institute, Rutgers University, Piscataway, NJ 08854, USA;

关键词: Down syndrome;    Locus Coeruleus;    Norepinephrine;    Designer receptors exclusively activated by designer drugs (DREADD);    Alzheimer's disease;    Memory;   

DOI  :  

来源: DOAJ

【 摘 要 】

The pontine nucleus locus coeruleus (LC) is the primary source of noradrenergic (NE) projections to the brain and is important for working memory, attention, and cognitive flexibility. Individuals with Down syndrome (DS) develop Alzheimer's disease (AD) with high penetrance and often exhibit working memory deficits coupled with degeneration of LC-NE neurons early in the progression of AD pathology. Designer receptors exclusively activated by designer drugs (DREADDs) are chemogenetic tools that allow targeted manipulation of discrete neuronal populations in the brain without the confounds of off-target effects. We utilized male Ts65Dn mice (a mouse model for DS), and male normosomic (NS) controls to examine the effects of inhibitory DREADDs delivered via an AAV vector under translational control of the synthetic PRSx8, dopamine β hydroxylase (DβH) promoter. This chemogenetic tool allowed LC inhibition upon administration of the inert DREADD ligand, clozapine-N-oxide (CNO). DREADD-mediated LC inhibition impaired performance in a novel object recognition task and reversal learning in a spatial task. DREADD-mediated LC inhibition gave rise to an elevation of α-adrenoreceptors both in NS and in Ts65Dn mice. Further, microglial markers showed that the inhibitory DREADD stimulation led to increased microglial activation in the hippocampus in Ts65Dn but not in NS mice. These findings strongly suggest that LC signaling is important for intact memory and learning in Ts65Dn mice and disruption of these neurons leads to increased inflammation and dysregulation of adrenergic receptors.

【 授权许可】

Unknown