Innate T Cells Govern Adipose Tissue Biology

immune cells resident in adipose tissue have important functions in local and systemic metabolic homeostasis. Nevertheless, these immune cell populations remain poorly characterized in bovines. Recently, we described diverse lymphocyte subpopulations in adipose tissue of Holstein-Friesian cows. Here, we aimed at characterising myeloid cell populations present in bovine adipose tissue using multicolour flow cytometry, cell sorting and histochemistry/immunohistochemistry. Macrophages, CD14 + CD11b + MHc-ii + CD45 + cells, were identified in mesenteric and subcutaneous adipose tissue, though at higher proportions in the latter. Mast cells, identified as SSC-A high CD11b −/+ CD14 − MHcii − CH138A − CD45 + cells, were also observed in adipose tissue and found at higher proportions than macrophages in mesenteric adipose tissue. Neutrophils, presenting a CH138A + CD11b + phenotype, were also detected in mesenteric and subcutaneous adipose tissue, however, at much lower frequencies than in the blood. Our gating strategy allowed identification of eosinophils in blood but not in adipose tissue although being detected by morphological analysis at low frequencies in some animals. A population not expressing CD45 and with the CH138A + CD11b − MHc-ii − phenotype, was found abundant and present at higher proportions in mesenteric than subcutaneous adipose tissue. The work reported here may be useful for further studies addressing the function of the described cells.www.nature.com/scientificreports www.nature.com/scientificreports/ colour-flow cytometry revealed the presence of CD14 + cells, CD172a + cells, CD11c + cells and CD163 + cells in the stromal vascular fraction (SVF) of subcutaneous and omental adipose tissue 23,24 . Recently, Aylward et al. 25 reported the presence of CD172a + CD11b + cells, CD11c + MHC-II + cells, and CD11b + CD11c + cells in mesenteric adipose tissue. However, these markers are not exclusive to macrophages but common to other myeloid cell populations or can be even expressed in non-hematopoietic cells. As an example, studies in humans and mice have shown that CD14 can be expressed in non-myeloid cells 26 such as preadipocytes 27 and epithelial cells 28 . Also, CD172a is expressed by granulocytes such as eosinophils 29 and mast cells 30 beside its expression in monocytes/ macrophages. Since mast cells 31,32 and eosinophils 3,33 have already been described in adipose tissue, single markers analysis limits the interpretation of the data. Therefore, to characterize the different myeloid cell populations in bovine adipose tissue we used a multicolour flow cytometry panel associated with cell sorting and histochemistry/immunohistochemistry analysis. Our strategy allowed identification and isolation of macrophages, mast cells and neutrophils with macrophages being observed at different proportions in mesenteric adipose tissue (MAT) and subcutaneous adipose tissue (SAT). We also showed that CD45 negative cells represent more than 40% of all the cells in the adipose tissue SVF of MAT. A non-leukocyte populat...

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confidence: 99%

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confidence: 99%

Characterization of Myeloid Cellular Populations in Mesenteric and Subcutaneous Adipose Tissue of Holstein-Friesian Cows

Oliveira

Pinto

Correia

et al. 2020

“…Functionally distinct NKT cell effector subpopulations, primed to secrete unique combinations of cytokines and defined by particular transcription factor expression patterns, potently modulate disparate aspects of immunity [49][50][51][52] . In this present study, we uncovered a small population of NKT cells that expressed low levels of the transcription factor YY1.…”

Section: Discussionmentioning

confidence: 99%

YY1lo NKT cells are dedicated IL-10 producers

Darcy

Denzin

Sant’Angelo

2020

Co-expression of Yin Yang 1 (YY1) is required for the full function of the transcription factor, PLZF, which is essential for the development of natural killer T cell (NKT cell) effector functions. Discordant expression of YY1 and PLZF, therefore, might define NKT cell subsets with distinct effector functions. A subset of NKT cells was identified that expressed low levels of YY1. YY1 lo nKt cells were found in all tissues, had a mature phenotype and, distinct from other NKT cells, expressed almost no ThPOK or Tbet. When activated, YY1 lo NKT cells produced little IL-4 or IFN-γ. YY1 lo nKt cells were found to constitutively transcribe IL-10 mRNA and, accordingly, produced IL-10 upon primary activation. Finally, we find that tumor infiltrating NKT cells are highly enriched for the YY1 lo subset. Low YY1 expression, therefore, defines a previously unrecognized NKT cell subset that is committed to producing IL-10.YY1 hi PLZF lo NKT cells and YY1 hi PLZF hi NKT cells, suggesting that differential TCRVβ usage did not impact the unique transcription factor expression pattern of the YY1 lo NKT cells. Scientific RepoRtS |(2020) 10:3897 | https://doi.

“…The adipose tissue is no longer regarded as a simple organ for lipid storage, but is recognized as an endocrine organ important for metabolism homeostasis 1,2 . It has been shown that immune cell populations resident in adipose tissue have a critical role in regulation of not only local but also systemic metabolic homeostasis 3,4 . Studies in humans and mice have shown that cells like γδ and NK T cells are enriched in the adipose tissue and have an important role in maintaining its homeostasis 3,5 .…”

Section: Introductionmentioning

confidence: 99%

“…It has been shown that immune cell populations resident in adipose tissue have a critical role in regulation of not only local but also systemic metabolic homeostasis 3,4 . Studies in humans and mice have shown that cells like γδ and NK T cells are enriched in the adipose tissue and have an important role in maintaining its homeostasis 3,5 . These populations interact with and promote T regulatory cells (Treg), an important population for the maintenance of an anti-inflammatory environment in that tissue 3,5 .…”

Section: Introductionmentioning

confidence: 99%

T cells in mesenteric and subcutaneous adipose tissue of Holstein-Friesian cows

Oliveira

Rasteiro

Correia

et al. 2019

The importance of immune cells present in the adipose tissue to metabolic homeostasis has been increasingly recognized. Nevertheless, in bovines few studies have so far addressed the immune cell populations resident in this tissue. Here we developed an eight-colour flow cytometry panel to address T cell populations present in bovine adipose tissue. Our results showed that γδ T cells, CD4 + and CD8 + CD3 + non-γδ T cells, as well as NK cells, are present in the mesenteric and subcutaneous adipose tissue of Holstein-Friesian cows. The frequency of both γδ T cells and CD8 + non-γδ T cells was found higher in mesenteric than in subcutaneous adipose tissue. The majority of T cells in adipose tissue presented a CD45RO + CD62L − phenotype, characteristic of effector memory cells, and the frequency of these cellular populations was higher than in the blood. The ratio of CD4 + T cells over CD8 + T cells was similar between subcutaneous and mesenteric adipose tissue but different from the one found in blood. Overall, our results highlight particular phenotypic characteristics of bovine adipose tissue T cell populations.