Abstract Rationale Obesity is associated with increased asthma risk, severity, and morbidity, but the mechanisms underlying this association are not fully understood. No pediatric studies of obesity-related asthma (ORA) have analyzed gene expression profiles in adipose tissue at the single-cell level. Methods We obtained omental (OM) adipose tissue in the GenOAAT study, a prospective cohort of youth, ages 6-20 years, with and without asthma. We isolated OM single nuclei, including from adipocytes, immune cells, and the stromovascular fraction using our robust protocols. Using oligo DNA-barcoded tagging antibodies, we conducted multiplexed single-nucleus RNA sequencing (snRNAseq) on 8 samples (asthma=4, controls=4). After quality control and normalization, data were integrated across batches using Harmony. Dimensionality reduction was performed with UMAP (uniform manifold approximation and projection), followed by clustering to define distinct cell populations. Cell types were annotated based on canonical markers and cross-referenced with published adipose single-cell atlases. To compare tissue and phenotype specific cellular compositions, we computed sample-level cell-type proportions. Results During QC, mitochondrial genes (0.5% of total counts) were filtered, and 28,607 high-quality cells with a median of 2,994 detected genes were retained for downstream analysis, confirming excellent data quality. Our analysis of snRNAseq from OM (asthma=4, controls=4) identified several relevant cell type clusters, including adipocytes, pre-adipocytes, vascular/stromal cells, and several immune cells (B-cells, T-cells, macrophages, and monocytes) (Figure 1A). We then identified cell type proportions within each sample based on gene expression profiles and performed unsupervised clustering analysis (Figure 1B). OM samples from youth with asthma had significantly higher proportions of macrophages, mesothelial cells, and mesothelium-derived fibroblasts; whereas OM samples from controls had higher proportions of adipocytes, adipose stem and progenitor cells, and endothelial cells (Figure 1B). The main genes that differentiated cell clusters/types include ADIPOQ, MAFB, CDH5, PDGFRA, JAM2, STEAP4, and other relevant genes associated with adipose tissue metabolism, inflammation, and immune cell signaling. Conclusions Cell composition and clustering in adipose tissue differed significantly between youth with obesity-related asthma and their peers without asthma. To our knowledge, this is the first transcriptomic analysis of adipose tissue and obesity-related asthma at single-cell resolution. Figure1: (A) Omental adipose tissue cell type clusters based on single-nucleus RNAseq. (B) Sample clustering based on cell type proportions estimated from snRNAseq. OM = omental adipose tissue. This abstract is funded by: HL149693 (NIH)
He et al. (Fri,) studied this question.