Fig. 5: Effects of icv FGF1 on Agrp neurons.

a UMAP clustering of neurons from the snRNA-seq dataset that confidently mapped to published datasets^16,17,18. Original cell type annotations from the published datasets are indicated in brackets. b Numbers of DEGs for neuron subclusters identified using repeated downsampling (10 cells/group/cell type/iteration, 100 iterations; n = 3 mice/group), median (IQR). c Volcano plot of pseudobulk DEGs in Agrp neurons from the Day 1 snRNA-seq dataset between FGF1 and vehicle. Red, genes with FDR < 0.05 and |log₂ fold change| > 0.25; green, genes with an |log₂ fold change| > 0.25; gray, genes below both thresholds. d Gene Ontology (biological process; red) and REACTOME (blue) terms enriched for DEGs in Agrp neurons at Day 1. Circle size denotes gene overlap with the identified geneset. e Principal component analysis of Agrp neurons sampled at Days 1 and 5 (vehicle and FGF1) revealed strong separation from other groups at PC4 and PC5, respectively (n = 3 mice/group Day 1, n = 2 mice/group Day 5), median (IQR). f Gene Ontology term (biological processes) of highly loading genes on PC5. g Normalized expression of Agrp and Npy in Agrp neurons across the 4 groups (FGF1, Days 1 and 5; vehicle, Days 1 and 5; n = 3 mice/group Day 1, n = 2 mice/group Day 5). h Top panel: representative electron microscopic images of coverage of synapses between axonal boutons (B) and dendritic spines (S) by peri-synaptic astrocytic in the ARC area of Lep^ob/ob mice. Bottom panel: immunostaining for Npy. Scale bar 500 nm. Quantification: dots represent percentage of astrocytic coverage for individual animals (mean of 30 synapses per animal, n = 4/group), mean ± SEM. Unpaired t test, two tailed, ***p < 0.0001 (not adjusted). i Contacts between GFAP(+) astrocytes (green) and Agrp(+) neurons in the ARC area (equivalent to outline in g) 1 week following icv FGF1 or vehicle injection of Lep^ob/ob. Yellow represents co-labeled GFAP-positive and Agrp-positive voxels. Scale bar 8 μm. Pixel dimensions: 0.057 × 0.057 × 0.500 microns. Quantification: dots represent mean contact volume over high power field (hpf: 116.5 × 116.5 microns) for individual animals (2 sections per animal, n = 4/group), mean ± SEM. Unpaired t test, two tailed, **p = 0.0093 (not adjusted). Source data and summary statistics are provided as a Source data file.