GEOapplication/xmlftp://ftp.ncbi.nlm.nih.gov/geo/series/GSE349nnn/GSE349117/primaryOK200TranscriptomicsMus musculusExpression profiling by high throughput sequencinghttps://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE349117GEOGSEfalseViral Delivery of Cre-Recombinase into the Hypothalamic Arcuate Nucleus Causes Cellular Toxicity and Energy Balance Phenotypes in Mice Independent of Cre-Mediated RecombinationThe Cre-lox system is widely used to interrogate gene function in a cell type-specific manner, and adeno-associated viruses (AAVs) have become a standard means of delivering Cre recombinase (AAV-Cre). Because some AAV-Cre vectors induce cellular toxicity in the brain, we tested whether different AAV-Cre vectors produce distinct toxicity and metabolic phenotypes when injected into the arcuate nucleus of the hypothalamus (ARC), a central node for energy homeostasis. Mice received bilateral stereotaxic ARC injections of AAV vectors expressing Cre, a catalytically inactive Cre mutant (dCre; CreY324F), or GFP, or were left untreated. Energy balance, body composition, ARC histology (NeuN, GFAP), and bulk RNA sequencing were assessed. Ai9 reporter mice were used to verify recombinase activity. One Cre-expressing vector induced hyperphagia and obesity, accompanied by loss of NeuN-positive cells and marked gliosis within the ARC. This phenotype persisted in mice harboring genomic loxP sequences, in which RNA sequencing revealed a pronounced inflammatory signature alongside negative enrichment of oxidative phosphorylation. The catalytically inactive mutant reproduced the same phenotype, indicating toxicity independent of Cre-mediated DNA cleavage. Newly engineered vectors placing Cre or dCre downstream of an internal ribosomal entry site (IRES) retained recombinase activity yet produced no detectable toxicity. Appropriate controls are essential when using AAV-Cre in metabolically sensitive brain regions. Catalytically inactive and expression-attenuated vectors offer improved tools for future studies.2026/10/04GSE349117GSM10087308GSM10087309GSM10087306GSM10087307GSM10087315GSM10087316GSM10087305GSM10087313GSM10087314GSM10087311GSM10087312GSM1008731034290349117Mus musculus