Analysis script for snRNA-seq of the mediobasal hypothalamus and dorsal vagal complex
Neuronal nutrient sensing in the hypothalamus and brainstem is thought to regulate energy and glucose homeostasis, yet how these brain regions respond to elevated adiposity or blood glucose remains unclear. We aimed to identify brain cell populations altered by diet-induced obesity (DIO), determine which also respond to acute hyperglycemia, and assess how DIO modifies these responses. We performed single-nucleus RNA-sequencing (snRNA-seq) on 75,787 cells from the arcuate nucleus, ventromedial hypothalamus (ARC/VMH), and dorsal vagal complex (DVC) of lean and diet-induced obese mice following 60-minute intravenous glucose or saline infusion. In lean mice, hyperglycemia triggered conserved transcriptional responses in astrocytes, oligodendrocytes, and notably in growth hormone-releasing hormone (Ghrh), consistent with reduced Ghrh neuron activity. DIO broadly altered gene expression across brain cell types, with pronounced effects in ARC astrocytes and specific neuronal populations, including Th/Slc6a3, Agrp, Ghrh, and Trh/Cxcl12 neurons. The activity-associated transcriptional responses in Ghrh and other neurons were largely absent or reversed in DIO. Genes enriched in both mouse and human GHRH neurons overlapped with loci linked to human glycemic traits, pointing to a conserved role in brain glucose regulation. These findings reveal the brain’s intrinsic capacity to sense hyperglycemia and demonstrate that this detection system is profoundly impaired in obesity. This study provides the first direct link between obesity-associated metabolic dysfunction and disrupted central glucose sensing.Neuronal nutrient sensing in the hypothalamus and brainstem is thought to regulate energy and glucose homeostasis, yet how these brain regions respond to elevated adiposity or blood glucose remains unclear. We aimed to identify brain cell populations altered by diet-induced obesity (DIO), determine which also respond to acute hyperglycemia, and assess how DIO modifies these responses. We performed single-nucleus RNA-sequencing (snRNA-seq) on 75,787 cells from the arcuate nucleus, ventromedial hypothalamus (ARC/VMH), and dorsal vagal complex (DVC) of lean and diet-induced obese mice following 60-minute intravenous glucose or saline infusion. In lean mice, hyperglycemia triggered conserved transcriptional responses in astrocytes, oligodendrocytes, and notably in growth hormone-releasing hormone (Ghrh), consistent with reduced Ghrh neuron activity. DIO broadly altered gene expression across brain cell types, with pronounced effects in ARC astrocytes and specific neuronal populations, including Th/Slc6a3, Agrp, Ghrh, and Trh/Cxcl12 neurons. The activity-associated transcriptional responses in Ghrh and other neurons were largely absent or reversed in DIO. Genes enriched in both mouse and human GHRH neurons overlapped with loci linked to human glycemic traits, pointing to a conserved role in brain glucose regulation. These findings reveal the brain’s intrinsic capacity to sense hyperglycemia and demonstrate that this detection system is profoundly impaired in obesity. This study provides the first direct link between obesity-associated metabolic dysfunction and disrupted central glucose sensing.