A transcriptional and cellular exploration of obesity and type-II diabetes in human adipose tissues
Data files
Oct 12, 2026 version files 9.80 GB
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Blood_Chemokine.zip
28.88 MB
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Flow_Data_1.xlsx
306.89 KB
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Histology.zip
9.77 GB
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Patient_Data_1.xlsx
11.85 KB
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README.md
30.82 KB
Abstract
Obesity is a major risk factor for type-II diabetes (T2D), yet many people living with obesity never develop it, and what makes some individuals susceptible is still unclear. To examine this at the level of adipose tissue, we collected paired omental and subcutaneous fat, together with blood, from 58 people with obesity undergoing bariatric surgery. Participants either had (Ob+T2D) or did not have (Ob) a clinical diagnosis of T2D. Subsets of the cohort were analysed with several methods: 1) single-cell RNA sequencing of adipose stromal cells (n = 10), 2) flow cytometry of adipose stromal cells and blood mononuclear cells, at baseline and after stimulation (n = 42), 3) stimulation of omental stromal cells with Toll-like receptor agonists (n = 20), 4) histology of adipose sections (n = 17), and 5) multiplex chemokine measurement in serum (n = 35). In T2D, the omental stromal compartment was remodelled, most prominently in mesothelial and endothelial cells. Mesothelial and IGFBP2+ cells took on a fibrotic, epithelial–mesenchymal transition-like state. Omental endothelial cells carried signatures of lipid overload, inflammation and antigen presentation. Innate T cells and macrophages differed in phenotype between the two fat depots, and innate T cells showed inflammatory profiles that diverged between omental and subcutaneous tissue. Together, the data point to depot-specific changes in adipose tissue in T2D, and to compensatory cell networks that could be targeted therapeutically. This deposit contains: 1) adipose histology images and adipocyte size measurements, 2) gated flow cytometry statistics 3) serum chemokine data, and 4) de-identified patient clinical metadata. Single-cell sequencing data are available from GEO (GSE278526).
William V Trim, Kseniia Petrova, Katie Healy, Brenneth M Stevens, John G Scanlan, Heather J Faust, Sara Svensson Akusjärvi, Katie L O'Brien, Donal O'Shea, Michael B Brenner, Helen Heneghan, and Lydia Lynch
Corresponding authors:
- William V. Trim, PhD — Harvard Medical School — William_Trim@hms.harvard.edu
- Lydia Lynch, PhD — Princeton University — lydialynch@princeton.edu
Description of the study
This dataset comes from a study of stromal and immune cells in paired subcutaneous and omental adipose tissue from people with obesity, with or without type-II diabetes (T2D). Samples were collected from 58 adults undergoing elective bariatric surgery in Ireland, between 2020 and 2021. All participants gave written informed consent (PHS IRB: 2019P001128). How samples were collected, processed and analysed is described in the Methods section of this Dryad record, and in full in the associated article.
Patients were grouped as obese (Ob, sometimes labelled MHO) or obese with type-II diabetes (Ob+T2D, sometimes labelled MUO). Ob+T2D required a clinical T2D diagnosis together with HbA1c ≥ 39 mmol/mol (≥ 5.7 %). Each of the 58 patients contributed to one or more of the following analyses, and the cohorts overlap:
- flow cytometry of adipose stromal cells and PBMCs: n = 42 (P01–P42)
- TLR-agonist stimulation of omental stromal cells: n = 20 (11 of these patients are also in the n = 42 flow cytometry cohort and 9 are not)
- single-cell RNA-sequencing: n = 10 (the same patients as the LPS + Poly(I:C) stimulation experiments)
- histology of whole adipose sections: n = 17
- multiplex chemokine/cytokine quantification in serum: n = 35
Patients are identified throughout by an anonymised patient number (P##), and Patient_Data_1.xlsx shows which analyses each patient contributed to. Patient_Data_1.xlsx lists 60 patient IDs (P01–P60). P43 and P54 did not have sufficient clinical information and were not used in the final analyses. They contribute no data to any other file in this deposit but are included in Patient_Data_1.xlsx for transparency, so the 58 analysed patients are the remaining 58 IDs.
Two related resources are not included in this deposit. Raw flow cytometry .fcs files can be requested by contacting William_Trim@hms.harvard.edu (see Flow_Data_1.xlsx, below). Single-cell RNA-sequencing raw data and analysis code are hosted elsewhere (see the section on single-cell RNA-sequencing, below).
Description of the data and file structure
This deposit (Trim et al. Dataset) consists of two compressed archives and two spreadsheets. The spreadsheets contain no formatting, formulas, merged cells, images or comments, and each sheet holds plain tabular data. Each archive, and the flow cytometry spreadsheet, corresponds to one experimental method. The second spreadsheet holds patient metadata.
Trim et al. Dataset/
├── Histology.zip (raw + AdipoSoft-analysed adipose histology images)
├── Flow_Data_1.xlsx (flow cytometry gated population data: fresh adipose/PBMC panels + stimulation panels)
├── Blood_Chemokine.zip (multiplex serum chemokine/cytokine assay: raw .fcs files + results as CSV)
└── Patient_Data_1.xlsx (patient clinical and anthropometric metadata)
Histology.zip
H&E-stained sections of formalin-fixed, paraffin-embedded adipose tissue, imaged at 10× magnification, with adipocyte size measured using the AdipoSoft plugin for ImageJ (see Methods).
Top-level structure:
Histology/
<patient>-Om/ or <patient> - Om/ Omental adipose tissue, patient <patient>
<patient>-SQ/ or <patient> - Sq/ Subcutaneous adipose tissue, patient <patient>
Patient identifiers are P-prefixed throughout (e.g. P28). Om = omentum; SQ/Sq = subcutaneous adipose.
Each patient/tissue folder contains:
| File pattern | Description |
|---|---|
| Image_#####.tif or lettered names (e.g. A1.tif) | Raw microscopy image, one per field of view |
<foldername>.xls (e.g. P28-Om.xls) |
Combined adipocyte measurement table for the whole sample, concatenating results across all fields of view. Despite the .xls extension this is a tab-delimited plain-text file, not a binary Excel file. Columns: row index, Label (source image filename), Area (adipocyte cross-sectional area, µ2), D-eq (equivalent diameter, µm). Each row is one segmented adipocyte |
Flow_Data_1.xlsx
Gated population statistics exported from FlowJo v10.8.1. Fresh adipose stromal cells and PBMCs were stained with Panels 1–3 (lymphocytes, innate lymphocytes, myeloid cells/granulocytes). Panel 4 was used after PMA/ionomycin stimulation and Panel 5 after TLR-agonist stimulation of omental stromal cells. PBMCs were stained with Panels 1, 2 and 4 only. Stimulation conditions, staining and the full antibody list are given in Methods.
Raw .fcs files are not included in this deposit. They cover all panels and patients described here, together with single-stain compensation controls, unstained controls, compensation matrices and, for the stimulation experiments, the paired unstimulated samples. They can be requested by contacting William_Trim@hms.harvard.edu.
Flow_Data_1.xlsx has two sheets:
| Sheet | Contents |
|---|---|
| Flow_All | All flow cytometry data from Panels 1–4 (fresh lymphocyte, innate lymphocyte, and myeloid/granulocyte panels, plus PMA/ionomycin stimulation), for subcutaneous adipose, omental adipose and PBMCs (n = 42 patients) |
| MSNL_Mac_Data | Mesothelial, macrophage and other stromal cell data from the omental TLR-agonist stimulation experiments (Panel 5; n = 20 patients) |
Flow_All sheet
One column per patient and one row per measured parameter. Patient columns run from column D to column AS (P01–P42): columns D–AA are Ob (MHO) patients (n = 24) and columns AB–AS are Ob+T2D (MUO) patients (n = 18). Group is also given by the T2DM row (0 = MHO, 1 = MUO) and in Patient_Data_1.xlsx.
| Column | Description |
|---|---|
| A — Data Type | Tissue and measurement type for the row (codes below). N/A or blank marks patient annotation rows at the top of the sheet |
| B — Patient / parameter | The population or parameter measured in that row. In the annotation rows it holds the label "Patient" (row 1); it is blank in rows 2–4 |
| C — Key | Unique row identifier combining columns A and B for the flow cytometry rows (e.g. SQ%-Live % of Tot). In the annotation rows it holds the row label instead, including the HTN, Dyslipidaemia and T2DM labels in rows 2–4 |
| D–AS — P## | Values for each patient. Row 1 gives the patient ID |
Patient annotation rows 1–4 at the top of the sheet give, for each patient: patient ID; HTN, Dyslipidaemia and T2DM (0 = null, 1 = positive). Group, sex, age band and the full clinical and anthropometric metadata are in Patient_Data_1.xlsx, below, linked by patient ID. Flow cytometry data start at row 5.
Data Type codes in column A:
| Code | Description |
|---|---|
SQ% |
Subcutaneous adipose stromal cells, population frequencies (%) |
OM% |
Omental adipose stromal cells, population frequencies (%) |
PB% |
Peripheral blood mononuclear cells (PBMCs), population frequencies (%) |
SQ# |
Subcutaneous adipose stromal cells, absolute cell counts (cells per gram of tissue) |
OM# |
Omental adipose stromal cells, absolute cell counts (cells per gram of tissue) |
PB# |
PBMCs, absolute cell counts (cells per µL of blood) |
In the percentage (%) blocks, the row label in column B gives the population and its reference gate (e.g. "CD206+ ATM % of CD45+" is CD206+ adipose tissue macrophages as a percentage of CD45+ cells). Within each tissue, rows cover:
- viability and CD45+ leukocytes
- monocytes, adipose tissue macrophage (ATM) subsets (CD9, CD63, CD206, CD36, HLA-DR, TREM2) and granulocytes (all three adipose tissue only; Panel 3)
- CD4+ and CD8+ T cell memory subsets (EMRA, naïve [NA], central memory [CM], effector memory [EM]) with CD36 and HLA-DR expression, and B cell subsets
- MAIT, iNKT, Vδ1 and Vδ2 cells with PLZF and RORγt expression, and Treg cells
- in rows marked "(stim)": cytokine production (IFNγ, IL-4, IL-10, IL-17A, IL-17F, TNF and their combinations) by MAIT, iNKT, CD4+, CD8+, γδ (yd) and lineage-negative (Lin-) cells after PMA/ionomycin stimulation (Panel 4)
PBMCs were not stained with Panel 3, so PB% and PB# have no myeloid or granulocyte rows.
In the absolute count (#) blocks, values are absolute cell numbers calculated using Precision Count Beads, expressed as cells per gram of adipose tissue (SQ#, OM#) or cells per µL of blood (PB#). Some row labels in these blocks keep the wording of the matching percentage row (e.g. "CD3+ % of CD45+" in the PB# block); in every # block the values are counts, not percentages.
Patients with no subcutaneous data (P01, P02, P10, P11, P16, P29, P36, P37) or no PBMC data (P36) have blank cells in those blocks.
MSNL_Mac_Data sheet
Two tables stacked vertically, one per stimulation condition, each with 10 patients (5 Ob+T2D [MUO] and 5 Ob [MHO]). Values are from TLR-agonist-stimulated samples. One column per patient; columns H and N are blank spacers.
| Rows | Condition | Patients |
|---|---|---|
| 1–81 | Full Stim — broad TLR agonist cocktail: Poly(I:C), LPS, R848, CpG | MUO: P12, P20, P27, P29, P42; MHO: P35, P36, P37, P38, P60 |
| 83–163 | LPS+PolyIC — LPS and Poly(I:C) only (the 10 patients used for scRNA-seq) | MUO: P39, P40, P52, P53, P57; MHO: P44, P45, P46, P58, P59 |
The first three rows of each table give the stimulation condition, the group (MUO or MHO), and the source sample name (Stimulated_P##.fcs, where P## is the patient ID).
| Column | Description |
|---|---|
| A | FlowJo gating path and statistic, separated by " | " (e.g. "Singlets/All Viable Cells/Live Cells/CD45+ | Freq. of Parent") |
| B | Short name of the population or parameter (e.g. CD45+, Meso IL6, FIPs TNF). Blank for intermediate and quadrant gates that have no short name |
| C–G | MUO patients |
| I–M | MHO patients |
Statistics named in column A are:
- Freq. of Parent: percentage of the parent gate
- Median (LIPIDTOX): median LipidTOX Green fluorescence intensity, labelled "LT" in column B
- Median (HLA-DR): median HLA-DR fluorescence intensity
Rows with an entry in column B and none in column A (e.g. "Macrophages (CD16-CD11b+) % of CD45+") are calculated values, not direct FlowJo exports.
Populations cover CD45+ leukocytes, CD16+ monocytes, CD16- macrophages split into CD11b+ and CD11b- subsets, and the CD45- compartment: endothelial cells (Endo), fibro-adipogenic progenitors (FIPs) and mesothelial cells (Meso). Each monocyte, macrophage, endothelial, FIP and mesothelial population has rows for IFNγ, IL-6, IL-17A and TNF production and IFNγ/TNF quadrant gates (Q1–Q4).
Blood_Chemokine.zip
Serum chemokines measured with the LEGENDplex™ human pro-inflammatory chemokine 13-plex bead assay (BioLegend). Serum preparation, acquisition and the quality filters applied in the associated article are described in Methods.
Blood_Chemokine.zip
18JULY2023_Chemokine_Serum Obesity/ 86 raw .fcs files (one 96-well plate)
Blood_Chemokine_Experiment.csv Assay run metadata
Blood_Chemokine_Standard_Curves.csv Standard-curve fit for each analyte
Blood_Chemokine_Predicted_Conc.csv Results: concentration per well and analyte
Blood_Chemokine_Plate_Layout.csv 96-well plate map
The 86 .fcs files comprise 16 standard-curve wells (8 standard concentrations × 2 replicates) and 70 patient sample wells (35 patients × 2 technical replicates). Patient well filenames give the patient ID, well ID and plate coordinate, e.g. P02_A3_A03.fcs = patient P02, well A3, plate position A03. Standard well filenames are numbered C0–C7 by well order on the plate. This numbering is not the standard's concentration level (see Blood_Chemokine_Predicted_Conc.csv, below).
The four CSV files (UTF-8, comma-separated) contain the results exported from the LEGENDplex™ analysis software. Each file is described below.
Blood_Chemokine_Experiment.csv gives the assay run metadata as field/value pairs: experiment name, number of standard and sample wells, analysing user, and report date. "MHO_Serum" is the experiment name assigned in the analysis software. The plate contains serum from both Ob (MHO) and Ob+T2D (MUO) patients.
Blood_Chemokine_Standard_Curves.csv has one row per analyte, with the bead plate coordinate in brackets, e.g. IL-8 (A4). Columns:
| Column | Description |
|---|---|
| Target (Bead) | Analyte and bead position |
| Fit | Curve model (5PL = five-parameter logistic) |
| IC50 | Curve midpoint, pg/mL |
| R² | Goodness of fit |
| N | Number of standard wells used |
| Converged | Whether the fit converged |
| LOD | Limit of detection, pg/mL |
| LOQ | Limit of quantification, pg/mL |
Blood_Chemokine_Predicted_Conc.csv has one row per well (86 rows). Columns:
| Column | Description |
|---|---|
| experiment | Experiment name |
| well | Source .fcs filename |
| patient_id | Patient ID (P##), taken from the well filename; blank for standard wells |
| patient_replicate | Technical replicate (1 or 2) for that patient; blank for standard wells |
| sample | Sample label assigned by the analysis software. For standard wells this is the standard's concentration level, from C7 (highest) to C0 (blank). For patient wells it is a sequential label (Sample1–Sample35) that does not identify the patient; use patient_id instead |
| dilution | Sample dilution factor (1 = neat) |
| replicate | Replicate number assigned by the analysis software. For patient wells, use patient_replicate instead |
| sample_type | Standard or Sample |
| IL-8 (A4) … MIP-1β (B9) | Concentration of each analyte, pg/mL |
patient_id and patient_replicate were added for this deposit, because the software's own sample and replicate labels do not follow patients.
Analyte values have three special forms:
- values prefixed with ">" are above the top of the standard curve (e.g. >10000.0)
- values prefixed with "<" are below that analyte's limit of detection, with the LOD given (e.g. <98.97)
- blank cells mean the software returned no concentration for that well
MIG and MIP-3α were not reported in the associated article, and replicates with a coefficient of variation above 30% were excluded from its analyses (see Methods). This file contains all values before those filters.
Blood_Chemokine_Plate_Layout.csv is a 96-well plate map, with rows A–H in the "row" column and plate columns 1–12. Each cell shows which standard well (C0–C7, numbered by well order as in the .fcs filenames) or patient (P##) occupies that position.
Patient_Data_1.xlsx
Patient-level clinical and anthropometric metadata, one row per patient (P01, P02, …), linking across all three data types above. Columns:
| Column | Description |
|---|---|
| Patient | Patient ID |
| Chemokine_Multiplex (0 = null, 1 = present) | 1 if this patient's serum was included in the Blood_Chemokine.zip LEGENDplex assay (n = 35) |
| TLR_Full_Stim (0 = null, 1 = present) | 1 if this patient's omental stromal cells were stimulated with the broader TLR agonist cocktail (Poly(I:C), LPS, R848, CpG); data in the Full Stim table of the MSNL_Mac_Data sheet of Flow_Data_1.xlsx (n = 10) |
| LPS-PolyIC Stim (0 = null, 1 = present) | 1 if this patient's omental stromal cells were stimulated with LPS + Poly(I:C) only; data in the LPS+PolyIC table of the MSNL_Mac_Data sheet of Flow_Data_1.xlsx (n = 10 — the same 10 patients used for scRNA-seq) |
| scRNAseq (0 = null, 1 = present) | 1 if this patient's paired omental/subcutaneous adipose was used for single-cell RNA-sequencing (n = 10; data hosted on GEO, not in this deposit — see the single-cell RNA-sequencing section, below) |
| Flow Cytometry (0 = null, 1 = present) | 1 if this patient's adipose stromal cells/PBMCs were profiled with Panels 1–4; data in the Flow_All sheet of Flow_Data_1.xlsx (n = 42) |
| Histology (0 = null, 1 = present) | 1 if this patient's adipose sections were imaged in Histology.zip (n = 17) |
| Group | MHO (obese, Ob) or MUO (obese with T2D, Ob+T2D) |
| Sex | M / F |
| Age band (years, at inclusion) | <40, 40-49, 50-59, ≥60 |
| BMI band (kg/2) | 35-44.9, 45-54.9, ≥55 |
| Glucose, tot. chol, TG, HDL, non-HDL, LDL (Calc) | Fasting bloods, mmol/L |
| CRP (<1 = 1) | C-reactive protein, mg/L; values below the assay's detection limit of 1 are recorded as 1 |
| Insulin | µU/mL |
| HbA1c (mmol/mol) Menarini HPLC | Glycated haemoglobin, measured by HPLC (Menarini) |
| T2DM | Clinically diagnosed type-II diabetes (0/1) |
| HTN | Hypertension (0/1) |
| Dyslipidaemia | 0/1 |
Blank cells throughout this dataset indicate missing data, data not available, or a value below the detectable limit of the relevant assay.
Single-cell RNA-sequencing (not included in this deposit)
Single-cell RNA-sequencing of paired omental and subcutaneous adipose stromal cells (n = 10 patients; 5 Ob, 5 Ob+T2D) was also performed as part of this study, but the sequencing data are not part of this Dryad deposit. They are hosted separately:
- Raw scRNA-seq data: GEO accession [GSE278526](https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE278526. FASTQ files were sanitised with BAMboozle to remove genetic variation before deposit. Patient and cell-type annotations are provided on the GEO record
- Analysis code and package versions: github.com/TRIMW/Defining-Metabolically-Healthy-Obesity-in-Humans
Library preparation, sequencing, patient demultiplexing and the downstream analysis workflow are summarised in Methods.
De-identification
All participants are identified only by an anonymised study code (P##) that is not derived from any personal information. The deposit contains no direct identifiers: no names, initials, dates of birth, dates of surgery or sampling, hospital or medical record numbers, or addresses.
To comply with Dryad's limit of three indirect identifiers, the participant-level data keep only:
- sex
- age, as a 10-year band (<40, 40-49, 50-59, ≥60), with the youngest and oldest participants grouped into open-ended bands
- BMI, as a band (35-44.9, 45-54.9, ≥55 kg/m2), with the top band capping extreme values
Exact age and BMI were removed from all participant-level files. Age is given only as a band in Patient_Data_1.xlsx and was removed from Flow_Data_1.xlsx. Height, weight, surgical risk scores (ASA, OSMRS), diabetes medication, other comorbidities and free-text notes, and the type of bariatric procedure were also removed. The location is given only at country level, and the recruiting hospitals are not named. Clinical laboratory values and diagnoses of T2D, hypertension and dyslipidaemia, all common conditions in this population, are retained because they define the study groups and are needed to reproduce the analyses. Histology images show adipose tissue sections only and contain no identifying features.
Sharing and access information
Data are released under a CC0 1.0 Universal waiver, as required by Dryad. All patient data have been de-identified as described above.
Raw flow cytometry .fcs files, including compensation controls and matrices, are not part of this deposit. They can be requested by contacting William_Trim@hms.harvard.edu.
Human subjects data
All participants are identified only by an arbitrary study code (P##) not derived from personal information. No direct identifiers are included (no names, initials, dates of birth, dates of surgery or sampling, medical record numbers or addresses). Indirect identifiers are limited to three: sex, age in 10-year bands (<40, 40–49, 50–59, ≥60) and BMI in bands (35–44.9, 45–54.9, ≥55 kg/m²), with open-ended top and bottom bands to mask outliers. Exact age, BMI, height, weight, medication use, surgical risk scores, procedure type, additional comorbidities and free-text clinical notes were removed. Recruitment sites are not named; location is given at country level only. Laboratory values and diagnoses of T2D, hypertension and dyslipidaemia, all common conditions in this population, are retained because they define the study groups and are required to reproduce the published analyses. Participants gave written informed consent under PHS IRB 2019P001128.
Full experimental detail is available in the associated article. A summary relevant to users of this dataset follows.
Participants, ethics and group assignment
Participants were 58 adults with obesity having elective bariatric surgery at St. Vincent’s University Hospital and St. Michael’s Hospital, Dublin, Ireland. They were recruited consecutively from July 2020 to June 2021, and each provided written informed consent. Each donated venous blood plus paired abdominal subcutaneous and omental adipose tissue, with omental tissue taken from the left lower edge of the greater omentum. The study was approved under PHS IRB protocol 2019P001128 and followed the Declaration of Helsinki (2013). Specimens and clinical records were separated from identifying information and given an anonymised code (P##).
Participants were assigned to one of two groups: obesity without T2D (Ob) or obesity with T2D (Ob+T2D). Assignment to Ob+T2D required both a clinical T2D diagnosis and an HbA1c of at least 39 mmol/mol (5.7 %, the pre-diabetes threshold) on routine pre-operative bloods (1). For exploratory analyses in the flow cytometry cohort, participants were also classified by whether they had hypertension and dyslipidaemia.
Not every participant contributed to every analysis. Allocation depended on how much tissue and blood was available on the day of surgery:
- flow cytometry of adipose stromal cells and PBMCs, unstimulated and stimulated: n = 42
- single-cell RNA sequencing (scRNA-seq) of adipose immune and non-immune stromal cells: n = 10. Omental tissue from these same participants was also used for TLR stimulation with LPS and Poly(I:C)
- TLR stimulation with LPS, Poly(I:C), R848 and CpG: omental tissue from 10 further participants
- histology: n = 17, using tissue left over after the other analyses
- serum chemokine/cytokine multiplex: n = 35, all available serum samples
Clinical characteristics for each analysis are tabulated in the associated article (Tables S1–S8 in associated article).
Sample collection and transport
Blood was drawn at the start of surgery and adipose tissue was taken during the procedure. Tissue went straight into plain Hanks’ Balanced Salt Solution (HBSS; Sigma-Aldrich, Darmstadt, DE) pre-chilled to 4 °C and reached the laboratory within 20–30 minutes. Venous blood from an antecubital vein was collected into BD Vacutainer tubes (BD, Berkshire, UK): serum-separation tubes for serum, and EDTA tubes for plasma and leukocytes.
Blood processing
Serum tubes were left to clot for about 30 minutes at room temperature (RT), then spun at 3,000 × g for 10 minutes at 4 °C. Serum was removed, held at −20 °C for about 1 hour and then moved to −80 °C until use.
PBMCs were isolated from the EDTA blood over a Ficoll density gradient (Sigma-Aldrich), and plasma was collected from the same separation. Part of the fresh PBMC fraction was set aside for flow cytometry. The rest was cryopreserved in RPMI 1640 (Gibco, Thermo Fisher Scientific, Leicestershire, UK) with 40 % foetal bovine serum (FBS) and 10 % DMSO (both Sigma-Aldrich), cooled at a controlled rate to −80 °C in Mr. Frosty containers (Thermo Fisher Scientific). Plasma was stored the same way as serum.
Adipose tissue processing and digestion
Tissue (1–12 g) was taken out of HBSS and rinsed on 100 µm gauze with PBS (Thermo Fisher Scientific) warmed to 37 °C to remove residual blood. It was then weighed and divided three ways:
- a 0.5–5 g piece for immediate enzymatic digestion
- a small piece into 10 % neutral buffered formalin at RT for histology
- the remainder frozen in CryoStor CS10 (STEMCELL Technologies, Cambridge, UK), cooled at a controlled rate to −80 °C in Mr. Frosty containers
For digestion, tissue was finely minced and placed in 6 mL of adipose buffer pre-warmed to 37 °C. Adipose buffer was pH 7.4 and contained:
- 140 mM NaCl, 4.7 mM KCl, 1.25 mM MgSO₄·7H₂O, 2.5 mM CaCl2·2H2O and 2.5 mM NaH2PO4·2H2O
- 10 mM HEPES
- 5.5 mM D-glucose
- 2 % BSA fraction V
All buffer components were from Sigma-Aldrich. Type-1 collagenase (250 U/mL; Worthington Biochemical, NJ, US) was added. Samples were shaken at 180–200 rpm and 37 °C for 45–60 minutes, and digestion was stopped by adding EDTA to 2 mM.
The digest was passed through 400 µm gauze and spun at 100 × g for 1 minute at RT. The remaining solution was spun at 300 × g for 7 minutes at RT. Red cells were then lysed for 10 minutes at RT in 9 volumes of lysis buffer (155.1 mM NH₄Cl, 9.9 mM KHCO₃, 0.1 mM EDTA; Sigma-Aldrich). After lysis, cells were diluted in adipose buffer and spun again (300 × g, 7 minutes, RT), and the supernatant was discarded. The cells were then resuspended in adipose buffer, filtered through 100 µm gauze and spun a final time under the same conditions. The final cell suspension was taken up in FACS buffer (PBS with 2 mM EDTA and 2 % FBS).
Stimulation of PBMCs and adipose leukocytes
PMA/ionomycin (Panel 4). PBMCs and adipose leukocytes were resuspended in complete RPMI and cultured at 37 °C, 5 % CO₂ and 95 % humidity. Complete RPMI was RPMI with 10 % FBS, 100 U/mL penicillin and 0.1 mg/mL streptomycin (Thermo Fisher Scientific), plus 2 mM L-glutamine. Stimulated wells received Cell Activation Cocktail without brefeldin A, which contains PMA and ionomycin (BioLegend). Brefeldin A (BioLegend; 5 µg/mL final) was added to both stimulated and unstimulated wells, and cells were cultured for 4 hours. They were then spun at 1,500 × g for 5 minutes, washed twice in FACS buffer and stained. Unstimulated wells were used to set cytokine gates.
TLR agonists (Panel 5). Cryopreserved omental tissue from the 10 scRNA-seq participants was thawed and digested as above, and the cells were cultured in complete RPMI under the same conditions. Stimulated wells received LPS (100 ng/mL; Enzo Life Sciences, NY, US) and Poly(I:C) (50 µg/mL; InvivoGen, CA, US). Omental cells from another 10 participants (5 per group) were stimulated in the same way with a broader TLR agonist cocktail:
- Poly(I:C), 50 µg/mL
- LPS, 100 ng/mL
- resiquimod (R848), 10 µg/mL
- CpG oligonucleotides, 1 µM
Except for LPS, the agonists came from InvivoGen. All wells contained brefeldin A (5 µg/mL), and cells were cultured for 6 hours with or without stimulation. They were then washed and stained as for Panel 4, and unstimulated wells were again used for gating.
Flow cytometry
Cells were stained with Zombie Aqua or Zombie Yellow fixable viability dye (BioLegend; 1:200 in FBS-free PBS) for 20 minutes at RT in the dark. Each sample was about 250,000 PBMCs or up to 500,000 adipose stromal cells. After a wash in FACS buffer (1,500 × g, 5 minutes), surface markers were stained for 20 minutes at RT in the dark. Staining was done in 100 µL of FACS buffer containing 5 % Human TruStain FcX Fc-receptor block (BioLegend) and antibodies at 1:50. Cells were then fixed in BioLegend fixation buffer and permeabilised according to the manufacturer’s instructions. Nuclear transcription factors used the FOXP3 Fix/Perm buffer set (BioLegend), and intracellular cytokines used the Intracellular Staining buffer (BioLegend). As a last step before acquisition, LipidTOX Green (Invitrogen) was added at 1:100 for 30 minutes at RT in the dark.
Fresh adipose leukocytes were stained with three panels: lymphocytes (Panel 1), innate lymphocytes (Panel 2), and myeloid cells and granulocytes (Panel 3). Panels 4 and 5 were used for the PMA/ionomycin and TLR stimulations respectively. PBMCs were stained with Panels 1, 2 and 4. Gating trees are shown in the associated article (Figs. S3–S6).
Precision Count Beads (BioLegend) were added to every sample to calculate absolute cell numbers. Data were acquired on BD FACSAria III and LSRFortessa cytometers. Compensation used UltraComp eBeads (Thermo Fisher Scientific), with one exception: in the TLR experiments, LipidTOX Green and Zombie Aqua were compensated using adipose tissue cells. Gating and export were done in FlowJo v10.8.1 (FlowJo LLC, OR, US).
Antibodies are listed below by fluorochrome as target (clone; supplier). BD = BD Biosciences; BL = BioLegend.
- BUV395: CD16 (3G8; BD)
- FITC: CD36 (5-271; BL); CD235a (GA-R2; BD); Vα7.2 (3C10; BL); CD8a (RPA-T8; BL)
- PerCP: CD45 (2D1; BD); CD34 (8G12; BD)
- PerCP-Cy5.5: IL-4 (MP4-25D2; BL)
- APC: CD15 (HI98; BD); HLA-DR (L243; BL); CD4 (A161A1; BL); Vδ3 (P11.5B; Beckman Coulter, CA, USA); CD1d tetramer (PBS-57; NIH Tetramer Core Facility, GA, US)
- Alexa Fluor 700: TNF (MAb11; BL); CD3 (UCHT1; BD); CD11b (ICRF44; BD)
- APC-H7: CD14 (MφP9; BD)
- APC-Cy7: CD31 (WM59; BL); CD4 (OKT4; BL); IL-17A (BL168; BL)
- BV421: TNF (MAb11; BL); HLA-DR (G46-6; BD); CD66b (G10F5; BD); CD1d tetramer (PBS-57; NIH Tetramer Core Facility); TCR-γδ (B1; BL)
- BV510: CD3 (OKT3; BL)
- BV605: CD14 (M5E2; BL); CD3 (SK7; BD); Siglec-8 (837535; BD); CD8 (SK1; BL); CD45 (HI30; BL)
- BV650: IFNγ (4S.B3; BD); CD8 (SK1; BL); CD161 (DX12; BD); CD206 (19.2; BD); RORγt (Q21-559; BD)
- BV711: CD3 (OKT3; BL); Vα7.2 (OF-5A12; BD); Vδ2 (B6; BL); CD11b (ICRF44; BD); CD19 (HIB19; BD); CD63 (H5C6; BL)
- BV785/BV786: CD45RA (HI100; BL); CD45 (HI30; BD, BV786); CD45 (HI30; BL, BV786); HLA-DR (G46-6; BD); CD4 (OKT4; BL); CD8 (SK1; BL)
- PE: CD161 (HP-3G10; BL); IL-10 (JES3-19F1; BL); IL-4 (MP4-25D2; BL); CD27 (L128; BD); MSLN (420411; R&D Systems, MN, USA); TREM2 (237920; R&D Systems)
- PE-CF594: PLZF (R17-809; BD); IL-6 (MQ2-13A5; BD); CD9 (M-L13; BD); IgD (IA6-2; BD); IFNγ (B27; BD); IL-17F (O33-782; BD)
- PE-Cy5: CD56 (B159; BD)
- PE-Cy7: IL-17A (BL168; BL); Vδ1 (TS8.2; Invitrogen); CD16 (3G8; BD); TCR-γδ (B1; BL); IFNγ (B27; BL); CD44 (G44-26; BD)
Adipose histology
Tissue was fixed in formalin for 24 hours at RT and taken through 2-hour ethanol steps of increasing concentration, from 30 % to 70 % in distilled water. It was then held overnight in 70 % ethanol at 4 °C. Samples were placed in cassettes (VWR International, Dublin, IE), dehydrated and embedded in paraffin. Sections of 7–10 µm were cut on a microtome (Leica Biosystems, IL, US), mounted on glass slides (VWR) and baked overnight at 60 °C. H&E staining was done on a Leica Autostainer XL ST5010, and slides were coverslipped on a Leica CV5030. Slides were imaged at 10× on an Olympus BX51 upright microscope. Adipocyte size was measured in batch with the Adiposoft plugin (2) for ImageJ (3). Crown-like structures were counted by hand and expressed per cm² of imaged tissue.
Serum chemokines
Serum chemokines were measured with the LEGENDplex human pro-inflammatory chemokine 13-plex bead assay (BioLegend), following the kit instructions. Data were acquired on a BD LSRFortessa and analysed with BioLegend’s online LEGENDplex analysis software. Two analytes were not reported in the associated article because too few samples gave usable data: MIG (monokine induced by gamma interferon) and MIP-3α (macrophage inflammatory protein-3α). Measurements whose technical replicates differed by a coefficient of variation above 30 % were excluded.
Single-cell RNA sequencing
Paired omental and subcutaneous tissue from 10 participants (5 per group) was digested as above. Stromal cells were sorted into CD45+ and CD45− fractions on a BD FACSAria III using the following stains (gating in Fig. S1 of the associated article):
- CD45–BV785 (BL)
- CD235a–FITC (BL)
- Zombie Aqua (BL)
- propidium iodide (Thermo Fisher Scientific)
Up to 5,000 cells per sample, half CD45+ and half CD45−, went forward. Cells from the five participants in each group were pooled and loaded on a single lane of a Chromium chip (10x Genomics, CA, US) with the Single Cell 3′ kit. cDNA and libraries were made according to the manufacturer’s protocol. Sequencing was done on an Illumina NextSeq 500 (Illumina, CA, US) at an average of 25,726 reads per cell. Per-cell transcript counts were generated with Cell Ranger v3.1, using the STAR aligner against the GRCh38-3.0.0 reference.
Demultiplexing. Cells were assigned to participants by genotype using souporcell (4), with no reference genotypes and the number of clusters set to five, one per participant in each pool. As validation, souporcell was first run separately on the omental and subcutaneous pools, and the SNP calls of the resulting clusters were compared by intersection over union. Each omental cluster matched exactly one subcutaneous cluster, as expected for paired samples. Sex-specific gene expression gave three female and two male clusters per pool, matching the three women and two men in each group (Fig. S2 of the associated article). For the final assignment, omental and subcutaneous data were merged within each group to increase coverage, and souporcell was rerun with five clusters (Ob and Ob+T2D kept separate). Cells not assigned to a single participant were discarded.
Quality control and clustering. Cells were kept if they expressed at least 100 genes and had less than 20 % mitochondrial reads, and genes were kept if detected in at least three cells. This left 25,830 omental and 9,127 subcutaneous cells. Downstream analysis used Scanpy (5) and Seurat (6) in R (7). Counts were normalised with analytic Pearson residuals (8), and the top 1,000 highly variable genes were used for PCA. A neighbourhood graph built from the PCA coordinates was used for UMAP embedding and Leiden clustering (9). Cell types were annotated by hand from marker gene expression, guided by published adipose tissue atlases (10–12). Participant and cell-type annotations are provided on the GEO record.
Downstream analyses.
- Differential abundance: per-participant cell-type proportions were tested with scCODA (13) within the pertpy framework (14).
- Cell–cell communication: predicted with MultiNicheNet (15), using the NicheNet v2 ligand–target and ligand–receptor networks (16, 17). To find shared outgoing signalling patterns, MultiNicheNet prioritisation scores summarised at group level (Ob+T2D vs Ob) were factorised separately for each depot by non-negative matrix factorisation (NMF R package (18)). Each sender cell type × ligand score matrix was split into four patterns, each a set of prioritised ligands shared across cell types, with scores giving each cell type’s contribution to each pattern.
- Multicellular programmes: inferred with DIALOGUE (19), which gave three programmes in omental tissue. The third captured genes involved in immune–stromal interactions.
- Trajectories: groups were integrated with Harmony (20). Diffusion pseudotime (21) in Scanpy was used for two proposed transitions: mesothelial cells → IGFBP2+ cells → fibro-adipogenic progenitors (FAPs), and FAPs → pre-adipocytes. Slingshot (22) trajectories were tested with tradeSeq (23) and visualised with ForceAtlas2 (24) at the cell level and PAGA (25) at the cluster level.
- Differential expression and enrichment: Ob+T2D was compared with Ob within each cell type using MAST (26) on single cells, with participant sex and cell coverage as covariates. Gene set enrichment was run with fgsea (27) against KEGG (28) and Gene Ontology (29, 30), ranking genes by sign(logFC) × −log10(FDR).
- Visualisation: ComplexHeatmap (31), seaborn (32) and ggplot2 (33).
Code and package versions are available at https://github.com/TRIMW/Defining-Metabolically-Healthy-Obesity-in-Humans. Raw data are at GEO (GSE278526). Before deposit, genetic variation was removed from the FASTQ files using BAMboozle v0.5.0 (34). Claude Code (Anthropic) was used to help customise the R and Python scripts for the MultiNicheNet, DIALOGUE, pseudotime and MOFA2 analyses.
Statistical analysis
Group comparisons. Normality was checked with the Shapiro–Wilk test, and p < 0.05 was taken as non-normal. Ob and Ob+T2D were compared with Welch’s or independent-samples t-tests for normal data. Non-normal data were compared with Mann–Whitney U tests with tie and continuity correction. Adipocyte size distributions were compared by two-way mixed-model ANOVA with Bonferroni post hoc correction. Correlations used Spearman’s ρ or Pearson’s r.
Covariates and comorbidities.
- Covariate effects were assessed by comparing ANOVA with ANCOVA for normal data, or Kruskal–Wallis with Quade tests for non-normal data.
- The cumulative burden of clinically diagnosed comorbidities was tested by simple linear regression, or by the Jonckheere–Terpstra test for non-normal data.
- The effects of combinations of T2D, hypertension and dyslipidaemia on flow cytometry readouts were tested by two-way ANOVA with type III sums of squares for normal data, or by the Scheirer–Ray–Hare test for non-normal data. Comparisons against the group negative for both conditions used Dunnett’s test, and comparisons across all groups used Benjamini–Hochberg FDR correction. Each pair of conditions was analysed by crossing positive/negative status for one (e.g. T2D −/+) with positive/negative status for the other (e.g., hypertension −/+).
- Sex differences were tested with the same two-way approach, followed by Tukey’s HSD.
Effect sizes and reporting. Effect sizes are Hedges’ g for n ≤ 20 and Cohen’s d for n > 20. Descriptive statistics are mean ± SD. Analyses were run in R, Python, SPSS (IBM, NY, US) and Prism (GraphPad Software, CA, US).
MOFA2. Proportional flow cytometry variables were analysed with Multi-Omics Factor Analysis v2 (MOFA2) (35). Variables were arranged into six views, one per sample type (blood, omental adipose, subcutaneous adipose) and condition (basal or PMA/ionomycin-stimulated), with participants shared across views. Basal data came from the fresh unstimulated panels (Panels 1–3). The unstimulated wells of the stimulation panels were not used: they received only 5–10 % of the cells and served solely as gating controls, so no basal cytokine data were generated. Variables were filtered by variance and inverse-normal transformed before training. Training requested 10 factors in slow convergence mode. Factors that explained less than 1 % of variance across all views were dropped, leaving 8. Per-participant factor scores were correlated with clinical and biochemical variables by Pearson correlation, with FDR correction across all factor–variable tests. The flow cytometry variables behind each factor were identified from its feature weights.
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