Affiliations: [a] Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| [b] Xiangya Hospital, Central South University, Changsha, Hunan Province, China
Correspondence to: Robert M. Friedlander, 200 Lothrop Street Suite B200, Presbyterian Hospital, Pittsburgh PA 15213, USA. Tel.: +1 412-647-6358; E-mail: [email protected].
Note: [#] These authors contributed equally to this work.
Abstract: Background:Selective serotonin reuptake inhibitors (SSRIs) target the serotonin transporter (SERT) and are commonly prescribed for depression in Huntington’s disease (HD) patients. However, SERT expression in HD has not been carefully evaluated in patients or mouse models. Objective:In this study, we investigated SERT levels in HD patients and HD mouse models. Methods:We obtained HD patient brain striatal samples and matched controls, as well as brain tissue from CAG140 and R6/2 mice. SERT mRNA and protein levels were analyzed using quantitative RT-PCR and immunoblotting. Results and Conclusions:We found that SERT protein, but not mRNA is markedly increased in grade 4 HD patient striatal tissue. These findings suggest posttranscriptional or translational SERT dysregulation as a possible etiologic factor modulating psychopathology in HD. Interestingly, SERT expression is variable in mouse models of the disease. Increased SERT levels are demonstrated in the brain of CAG140 mice, a full-length knock-in mouse model of the disease, but not in the striatum of the R6/2 fragment murine model of the disease. Based on this parameter, the CAG140 huntingtin knock-in mouse model is more suitable than the R6/2 model for the study of serotonergic pathway pathology in Huntington’s disease.