bims-adipim Biomed News
on Adipose immunity and immunometabolism
Issue of 2023‒10‒01
four papers selected by
Matthew C. Sinton, University of Glasgow

  1. STAR Protoc. 2023 Sep 23. pii: S2666-1667(23)00574-9. [Epub ahead of print]4(4): 102607
      Pro-preadipocytes are adipocyte progenitor cells within subcutaneous adipose tissue that are conserved in human adipose tissue with distinct cellular energetics. Here, we detail a protocol to quantify cellular oxygen consumption rates of primary human cells harvested from adipose tissue. We describe steps for primary cell expansion, cell seeding, transfection, differentiation, and respirometry followed by Agilent Seahorse Analytics. The measurement of bioenergetic profiles and resulting data further expand our knowledge of the functional properties of primary cells isolated from adipose tissue. For complete details on the use and execution of this protocol, please refer to Chen et al. (2023).1.
    Keywords:  Cell Biology; Cell Culture; Cell Isolation; Metabolism
  2. J Endocrinol. 2023 Sep 01. pii: JOE-23-0180. [Epub ahead of print]
      The prevalence of obesity is increasing exponentially across the globe. The lack of effective treatment options for long-term weight loss has magnified the enormity of this problem. Studies continue to demonstrate that adipose tissue holds a biological memory that is one of the most important determinant of long-term weight homeostasis. This phenomenon is consistent with the metabolically dynamic role of adipose tissue: it adapts and expands to store for excess energy and serves as an endocrine organ capable of synthesizing a number of biologically active molecules that regulate metabolic homeostasis. An important component of the plasticity of adipose tissue is the extracellular matrix, essential for structural support, mechanical stability, cell signaling and function. Chronic obesity upends a delicate balance of extracellular matrix synthesis and degradation, and the ECM accumulates in such a way that prevents the plasticity and function of the diverse cell types in adipose tissue. A series of maladaptive responses among the cells in adipose tissue lead to inflammation and fibrosis, major mechanisms that explain the link between obesity and insulin resistance, risk of type 2 diabetes, cardiovascular disease, and non-alcoholic fatty liver disease. Adipose tissue fibrosis persists after weight loss and further enhances adipose tissue dysfunction if weight is regained. Here, we highlight the current knowledge of the cellular events governing adipose tissue ECM remodeling during development of obesity. Our goal is to delineate the relationship more clearly between adipose tissue ECM and metabolic disease, an important step towards better defining the pathophysiology of dysfunctional adipose tissue.
  3. Cell Rep. 2023 Sep 27. pii: S2211-1247(23)01152-X. [Epub ahead of print]42(10): 113140
      Dietary fiber strongly impacts the microbiota. Here, we show that a low-fiber diet changes the small intestinal (SI) microbiota and impairs SI Th17, TCRαβ+CD8αβ+ and TCRαβ+CD8αα+ intraepithelial T cell development. We restore T cell development with dietary fiber supplementation, but this defect becomes persistent over generations with constant low-fiber diets. Offspring of low-fiber diet-fed mice have reduced SI T cells even after receiving a fiber-rich diet due to loss of bacteria important for T cell development. In these mice, only a microbiota transplant from a fiber-rich diet-fed mouse and a fiber-rich diet can restore T cell development. Low-fiber diets reduce segmented filamentous bacteria (SFB) abundance, impairing its vertical transmission. SFB colonization and a fiber-rich diet partially restore T cell development. Finally, we observe that low-fiber diet-induced T cell defects render mice more susceptible to Citrobacter rodentium infection. Together, these results demonstrate the importance of fiber to microbiota vertical transmission and host immune system development.
    Keywords:  CD8αβ(+) IEL; CP: Immunology; CP: Microbiology; IEL T cells; Th17; dietary fiber; interleukin 17; intraepithelial; microbiota; segmented filamentous bacteria
  4. Sci Rep. 2023 Sep 28. 13(1): 16350
      Reduction in visceral adipose tissue (VAT) mass reduces body weight and metabolic disease risk in obese patients. However surgical removal of VAT is highly invasive and thus not clinically feasible. We developed an injectable ice slurry for selective reduction of adipose tissue through cryolipolysis. The aim of this study was to investigate safety, feasibility and mechanism of ice slurry-induced cryolipolysis of VAT. Perigonadal VAT in diet-induced obese mice and rats was subjected to slurry or sham treatment. Body weight and blood chemistry were monitored for 56 days post-treatment. Histological analysis and molecular studies were performed to elucidate mechanisms of fat reduction. Treatment of VAT was well tolerated in all animals. Slurry induced adipocyte cell death via selective cryolipolysis; significant weight loss was noted at day 21 post-treatment. RNA sequencing from treated VAT samples showed increased expression of genes involved in inflammation, immune response, collagen biosynthesis and wound healing, and decreased expression of adipokines. This study demonstrates that slurry treatment is safe and effective in inducing cryolipolysis of VAT and subsequent weight loss in mice. Ice slurry is promising as a minimally-invasive treatment to reduce visceral adipose tissue.