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Objective: The objective of this study was to identify the transcriptional landscape of insulin resistance (IR) in subcutaneous adipose tissue (SAT) in humans across the spectrum of obesity., Methods: We used SAT RNA sequencing in 220 individuals with metabolic phenotyping., Results: We identified a 35-gene signature with high predictive accuracy for homeostatic model of IR that was expressed across a variety of non-immune cell populations. We observed primarily "protective" IR associations for adipocyte transcripts and "deleterious" associations for macrophage transcripts, as well as a high concordance between SAT and visceral adipose tissue (VAT). Multiple SAT genes exhibited dynamic expression 5 years after weight loss surgery and with insulin stimulation. Using available expression quantitative trait loci in SAT and/or VAT, we demonstrated similar genetic effect sizes of SAT and VAT on type 2 diabetes and BMI., Conclusions: SAT is conventionally viewed as a metabolic buffer for lipid deposition during positive energy balance, whereas VAT is viewed as a dominant contributor to and prime mediator of IR and cardiometabolic disease risk. Our results implicate a dynamic transcriptional architecture of IR that resides in both immune and non-immune populations in SAT and is shared with VAT, nuancing the current VAT-centric concept of IR in humans., (© 2024 The Authors. Obesity published by Wiley Periodicals LLC on behalf of The Obesity Society.)

Obesity-associated inflammation is a systemic process that affects all metabolic organs. Prominent among these is adipose tissue, where cells of the innate and adaptive immune system are markedly changed in obesity, implicating these cells in a range of processes linking immune memory to metabolic regulation. Furthermore, weight loss and weight cycling have unexpected effects on adipose tissue immune populations. Here, we review the current literature on the roles of various immune cells in lean and obese adipose tissue. Within this context, we discuss pharmacological and nonpharmacological approaches to obesity treatment and their impact on systemic inflammation.

While antiretroviral therapy (ART) has proven effective in suppressing viremia and disease progression among people living with human immunodeficiency virus (HIV; PLWH), suboptimal CD4 + T cell reconstitution remains a major obstacle in nearly 30% of ART-treated individuals. Epidemiological studies demonstrate that obesity, or a body mass index (BMI) ≥ 30 kg/m 2 , is positively correlated with greater CD4 + T cell recovery in PLWH on ART. Leptin is a known immunomodulator that is produced in proportion to fat mass and is increased in obese individuals, including PLWH. We hypothesized that CD4 + T cells from obese PLWH have increased cell proliferation and cytokine production compared to cells from lean PLWH, potentially modulated by differential effects of leptin signaling. To test this hypothesis, peripheral blood mononuclear cells from obese and lean PLWH with long-term virologic suppression on the same ART regimen were pretreated with recombinant leptin and then stimulated with anti-CD3/CD28 or PMA/ionomycin to measure Ki67 expression, leptin receptor (LepR) surface expression and cytokine production. In the absence of leptin, Ki67 expression and IL-17A production were significantly higher in CD4 + T cells from obese compared to lean PLWH. However, LepR expression was significantly lower on CD4 + T cells from obese compared to lean PLWH. After leptin treatment, Ki67 expression was significantly increased in CD4 + T cells from obese PLWH compared to the lean participants. Leptin also increased IL-17A production in CD4 + T cells from obese healthy controls. In contrast, leptin decreased IL-17A production in CD4 + T cells from both obese and lean PLWH. Combined, these results demonstrate that obesity is associated with greater CD4 + T cell proliferation among PLWH, and that higher circulating leptin levels in obesity may contribute to improved CD4 + T reconstitution in PLWH initiating ART., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Fuseini, Smith, Nochowicz, Simmons, Hannah, Wanjalla, Gabriel, Mashayekhi, Bailin, Castilho, Hasty, Koethe and Kalams.)

Aims: To investigate the hypothesis that weight loss with the glucagon‐like peptide‐1 receptor agonist (GLP‐1RA) liraglutide alone would lead to a greater reduction in the proportion of fat to lean tissue mass when compared to caloric restriction (CR) alone, as well as when compared to treatment with sitagliptin, a dipeptidyl peptidase‐4 (DPP‐4) inhibitor, that also enhances GLP‐1 activity ‐ to determine the independent effects of each treatment. Methods: A total of 88 adults with obesity and prediabetes were randomized to 14 weeks of intervention with CR (−390 kcal/d), liraglutide (1.8 mg/d), or the dipeptidyl peptidase‐4 inhibitor sitagliptin (100 mg/d) as a weight‐neutral comparator. Changes between groups in appetite and hunger ratings measured via visual analogue scales, dietary intakes, body weight, body composition via dual energy x‐ray absorptiometry, and resting energy expenditure via indirect calorimetry were assessed using the Kruskal‐Wallis test or Pearson's chi‐squared test. Results: Weight loss ≥5% of baseline body weight occurred in 44% of participants in the CR group, 22% of the liraglutide group and 5% of the sitagliptin group (p = 0.02). The ratio of fat to lean mass decreased by 6.5% in the CR group, 2.2% in the liraglutide group, and 0% in the sitagliptin group (p = 0.02). Visceral fat reduced by 9.5% in the CR group, 4.8% in the liraglutide group, and 0% in the sitagliptin group (p = 0.04). A spontaneous reduction in dietary simple carbohydrates in the CR group was associated with improved homeostatic model assessment of insulin resistance score (HOMA‐IR). Conclusions: Although both liraglutide and CR are valuable strategies for cardiometabolic risk reduction, CR was associated with greater weight loss and more favourable improvements in body composition than treatment with liraglutide alone. Differences in the response to each of these interventions enables patients to be stratified to the most optimal intervention for their personal risk factors. [ABSTRACT FROM AUTHOR]

• sEH inhibition decreases adipose tissue IFNγ-producing T helper cells and secreted TNFα. • sEH inhibition does not affect adipose tissue IL-17A production. • Modulating the sEH/EET pathway has anti-inflammatory potential in humans. Adipose tissue contains a complex immune environment and is a central contributor to heightened systemic inflammation in obese persons. Epoxyeicosatrienoic acids (EETs) are lipid signaling molecules that decrease inflammation in obese animals, but their effect on inflammation in humans is unknown. The enzyme soluble epoxide hydrolase (sEH) hydrolyzes EETs to less active diols, and we hypothesized that pharmacologic sEH inhibition would decrease adipose inflammation in obese individuals. We treated obese prediabetic adults with the sEH inhibitor GSK2256294 versus placebo in a crossover design, collected subcutaneous abdominal adipose tissue via lipoaspiration and characterized the tissue T cell profile. Treatment with GSK2256294 decreased the percentage of pro-inflammatory T cells producing interferon-gamma (IFNγ), but not interleukin (IL)-17A, and decreased the amount of secreted tumor necrosis factor-alpha (TNFα). Understanding the contribution of the EET/sEH pathway to inflammation in obesity could lead to new strategies to modulate adipose and systemic inflammation. [ABSTRACT FROM AUTHOR]