1973-P: Single-Nuclei Transcriptomics of Human Adipose Tissue Identify Distinct Adipocyte Progenitor Subpopulations in Type 2 Diabetes

Abstract

Altered adipocyte function underlies type 2 diabetes (DM) pathogenesis. We hypothesized that adipocyte dysfunction in visceral adipose tissue (VAT) in DM originates from distinct adipocyte progenitor cell (APC) subpopulations. VAT was collected from bariatric surgery patients with (HbA1c>6.5) and without DM (NDM, HbA1c<5.7). Single-nuclei RNA sequencing was performed in VAT nuclei (n= 1 NDM, 2 DM) using 10X Genomics. Transcriptionally distinct cell subpopulations were identified by DEG: mature adipocytes (ADIPOQ, LEP), endothelial cells (VWR), immune cells (F13A1, MSR1), and two major APC subpopulations (S1: FABP4, ADIRF, ITLN1 and MSLN; S2: APOD, CFD and WISP2). S2 was uniquely identified by the upregulation of extracellular matrix accumulation and fibrosis markers: LUM, DCN, FBN1, and COL1A1, 3A1, 6A1 and 6A3. S2 had higher expression of APC and committed preadipocyte markers, such as PLIN1, GNAI1, CXCL14, CP, and CRISPLD2, while S1 had higher mesothelial-like cell markers GPM6A, PKHD1L1, LRRN4, CXADR, SLPI, and UPK3B. We FACS-isolated S1 and S2 from VAT CD31-CD45- cells (n= 3 NDM, 5 DM) using the surface marker TM4SF1, which was abundantly expressed in S1, but not S2. TM4SF1 expression (qPCR) was 50% higher in S1 (TM4SF1+) than in S2 (TM4SF1-). TM4SF1 immunostaining of human SVF confirmed distinct APC subpopulations. S1 corresponded to 15 ± 3% and S2 to 69 ± 2% of CD31-CD45- cells. In DM compared to NDM, S2 fraction was increased by 12% while S1 was decreased by 45%. We tested the metabolic function of S1 and S2 sorted from 5 DM VAT. Both subpopulations differentiated into lipid-filled adipocytes upon adipogenic induction in vitro. However, S2 compared to S1, manifested decreased proliferation and increased intracellular lipid accumulation and lipolytic response, consistent with a pro-hypertrophic, lipolytic adipocyte phenotype in DM. Our data suggest that distinct APC subpopulations in human obese VAT contribute to adipose tissue dysfunction in DM. Disclosure C. Strieder-Barboza: None. C.G. Flesher: None. L.M. Geletka: None. R.W. ORourke: None. C.N. Lumeng: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases (R01DK115190, DK090262)