RT Journal Article
SR Electronic
T1 Microarray profiling of hypothalamic gene expression changes in Huntington’s disease mouse models
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.03.15.484411
DO 10.1101/2022.03.15.484411
A1 Dickson, Elna
A1 Dwijesha, Amoolya Sai
A1 Andersson, Natalie
A1 Lundh, Sofia
A1 Björkqvist, Maria
A1 Petersén, Åsa
A1 Soylu-Kucharz, Rana
YR 2022
UL http://biorxiv.org/content/early/2022/03/17/2022.03.15.484411.abstract
AB Structural changes and neuropathology in the hypothalamus have been suggested to contribute to the non-motor manifestations of Huntington’s disease (HD), a neurodegenerative disorder caused by an expanded CAG repeat in the huntingtin (HTT) gene. In the present study, we investigated whether transcriptional changes would be part of hypothalamic pathology induced by the disease-causing huntingtin (HTT) protein. We performed microarray analysis using the Affymetrix platform on total hypothalamic RNA isolated from two HD mouse models and their littermate controls; BACHD mice with ubiquitous expression of full-length mutant HTT (mHTT) and wild-type mice with targeted hypothalamic overexpression of either wild-type HTT (wtHTT) or mHTT fragments. To analyze microarray datasets (34760 variables) and obtain functional implications of differential expression patterns, we used Linear Models for Microarray Data (limma) followed by Gene Set Enrichment Analysis (GSEA) using ClusterProfiler. Limma identified 735 and 721 significantly differentially expressed genes (adjusted p < 0.05) in hypothalamus of AAV datasets wtHTT vs control and mHTT vs control. In contrast, for BACHD datasets and the AAV mHTT vs. wtHTT dataset, none of the genes were differentially expressed (adjusted p-value > 0.05 for all probe IDs). In AAV groups, from the combined limma with GSEA using ClusterProfiler, we found both shared and unique gene sets and pathways for mice with wtHTT overexpression compared to mice with mHTT overexpression. mHTT caused widespread suppression of neuroendocrine networks, as evident by GSEA enrichment of GO-terms related to neurons and/or specific neuroendocrine populations. Using qRT-PCR, we confirmed that mHTT overexpression caused significant downregulation of key enzymes involved in neuropeptide synthesis, including histidine and dopa decarboxylases, compared to wtHTT overexpression. Multiple biosynthetic pathways such as sterol synthesis were among the top shared processes, where both unique and shared genes constituted leading-edge subsets. In conclusion, mice with targeted overexpression of HTT (wtHTT or mHTT) in the hypothalamus show dysregulation of pathways, of which there are subsets of shared pathways and pathways unique to either wtHTT or mHTT overexpression.Competing Interest StatementThe authors have declared no competing interest.AAVadeno-associated viral vectorAvpVasopressinBACbacterial artificial chromosomeBMIbody mass indexCckrCholecystokinin receptorCxclC-X-C motif chemokinesDdcdopa decarboxylaseFAfatty acidFCfold changeGAPDHglyceraldehyde 3-phosphate dehydrogenaseGFPgreen fluorescent proteinGrhGrowth hormoneHcrtorexin/hypocretin proteinHDHuntington’s diseaseHdchistidine decarboxylaseHTThuntingtinIgImmunoglobulinIgfInsulin-like growth factorlimmaLinear Models for Microarray AnalysisMaoMonoamide oxidaseNESnormalized enrichment scoreNmNeuromedinOxtOxytocinPtgerprostaglandin E receptorqRT-PCRquantitative real-time polymerase chain reactionrAAV5recombinant AAV vector serotype 5RINRNA integrity numberRMARobust Multi-Array AverageSREBPSterol-regulatory element binding proteinStoml3Stomatin-like protein 3SstSomatostatinSyn-1Synapsin-1Sv2cSynaptic vesicle glycoprotein 2CTacr3Tachykinin receptor 3ThTyrosine-hydroxylaseTyrTyrosinaseWTwild-typewtHTTwild-type huntingtinmHTTmutant huntingtin