Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2015 Jan 13;112(2):482-7.
doi: 10.1073/pnas.1423486112. Epub 2014 Dec 30.

Appearance and disappearance of the mRNA signature characteristic of Treg cells in visceral adipose tissue: age, diet, and PPARγ effects

Affiliations

Appearance and disappearance of the mRNA signature characteristic of Treg cells in visceral adipose tissue: age, diet, and PPARγ effects

Daniela Cipolletta et al. Proc Natl Acad Sci U S A. .

Abstract

A unique population of Foxp3(+)CD4(+) regulatory T (Treg) cells resides in visceral adipose tissue (VAT) of lean mice, especially in the epididymal fat depot. VAT Tregs are unusual in their very high representation within the CD4(+) T-cell compartment, their transcriptome, and their repertoire of antigen-specific T-cell receptors. They are important regulators of local and systemic inflammation and metabolism. The overall goal of this study was to learn how the VAT Treg transcriptome adapts to different stimuli; in particular, its response to aging in lean mice, to metabolic perturbations associated with obesity, and to certain signaling events routed through PPARγ, the "master-regulator" of adipocyte differentiation. We show that the VAT Treg signature is imposed early in life, well before age-dependent expansion of the adipose-tissue Treg population. VAT Tregs in obese mice lose the signature typical of lean individuals but gain an additional set of over- and underrepresented transcripts. This obese mouse VAT Treg signature depends on phosphorylation of the serine residue at position 273 of PPARγ, in striking parallel to a pathway recently elucidated in adipocytes. These findings are important to consider in designing drugs to target type 2 diabetes and other features of the "metabolic syndrome."

Keywords: Foxp3; inflammation; obesity; regulatory T cell; type 2 diabetes.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
Treg dynamics and phenotype with aging. Tregs were isolated from VAT and spleen of lean B6 males at the indicated ages. (A) Cytofluorometric analysis of Foxp3+CD4+CD3+ T cells. (Left) Representative dot plots. Numbers indicate the percentage Foxp3+ of CD4+ cells for that particular experiment. (Right) Summary data from at least three independent experiments. (B) Treg numbers for the same mice. (C) As per A, except Gata3+Foxp3+ cells were examined. Numbers refer to the percentage Gata3+ of Foxp3+ cells for that particular experiment. Mean ± SD; **P < 0.01; ***P < 0.001; NS, not significant; by the Student’s t test.
Fig. 2.
Fig. 2.
Treg transcriptome evolution with aging. (A) Normalized microarray-determined expression values for transcripts from VAT vs. LN Tregs of B6 mice. Values in the corners refer to numbers of transcripts up- (Upper) or down- (Lower) regulated in VAT Tregs. Lines indicate the twofold cutoff. (B) As in panel a except LN transcriptomes from 5- and 25-wk-old mice are compared. (C) Same data as in A except the VAT Treg up- (pink) and down- (green) signatures are overlain (from Dataset S1). (D) Principal components analysis of the same microarray data.
Fig. 3.
Fig. 3.
Treg numbers and phenotype in obese mice. (AC) Treg cell representation in the CD4+ compartment. Cells were isolated from the VAT and spleen of 14-wk-old B6-ob/ob vs. B6-WT mice or of B6 mice fed HFD vs. NCD between the ages of 8 and 16 wk. Percentage Foxp3+ of CD4+ T cells (A), number of such cells (B), and percentage Gata3+ of Foxp3+ cells were analyzed and displayed as per the corresponding panels in Fig. 1. For AC, mean ± SD; *P < 0.05; **P < 0.01; ***P < 0.001; NS, not significant; by the Student’s t test. (D) Volcano plots comparing transcriptomes of obese and lean mice in the two models. Overlain are the VAT Treg up- (pink) and down- (green) signatures (from Dataset S1). P values from the χ2 test. (E) Representative dot plots of Klrg1 (Left) and CCR2 (Right) expression by VAT and spleen Tregs from obese mice and their lean controls. Percentages refer to the fraction of Foxp3+ cells constituted by the gated population. (F) Volcano plots comparing transcriptomes of obese and lean mice for the two models. Highlighted are the transcripts up- (orange) or down- (aqua) regulated ≥1.5-fold in obese mice (with a P value of ≤0.05 in three replicates). The omVAT Treg up- and down-signatures sum the altered transcripts from the two models (Dataset S2).
Fig. 4.
Fig. 4.
PPARγ and transcriptome changes with obesity. (A) Volcano plot comparing the VAT Treg transcriptomes of mice lacking PPARγ only in Tregs (Treg Pparg mut) vs. of their WT littermates (Pparg WT). Highlighted are the omVAT Treg up- (orange) and down- (aqua) signatures (from Dataset S2). P values from the χ2 test. (B) Pparg transcript levels. Extracted from the microarray data of Fig. 3. Mean ± SD. NS = P value not significant by the Student’s t test.
Fig. 5.
Fig. 5.
Effect of PPARγ phosphorylation on the VAT Treg signatures. Naïve CD25CD4+ T cells were stimulated ex vivo, and were transduced with retroviruses encoding Foxp3 and WT Pparg (Pparg WT) or Pparg bearing the S273A phosphorylation-site mutation. Infected cells were treated with TNFα or vehicle in the presence or absence of the Cdk5 inhibitor, SR1664, and then were sorted for GFP and Thy1.1 positivity before RNA processing. (AD) Microarray analysis. Volcano plots comparing the effects of TNFα (A), of the S273A mutation in the absence (B) or presence (C) of TNFα, and of the Cdk5 inhibitor, SR 1664, in the presence of TNFα (D). Highlighted are the omVAT Treg up- (orange) and down- (aqua) signatures. P values from the χ2 test. (E) Western blotting. Same samples as in AD, except an additional sample from cells treated with TNFα plus pio was included. (Left) An example blot using Abs that detect total PPARγ (clone E-8, Santa Cruz) or PPARγ phosphorylated at position 273 (7). (Right) Quantification from two experiments. For each experiment, the value for vehicle-treated cells was set at 1. Mean ± SD; *P = <0.05; NS, not significant; by the Student’s t test.

Similar articles

Cited by

References

    1. Osborn O, Olefsky JM. The cellular and signaling networks linking the immune system and metabolism in disease. Nat Med. 2012;18(3):363–374. - PubMed
    1. Mathis D. Immunological goings-on in visceral adipose tissue. Cell Metab. 2013;17(6):851–859. - PMC - PubMed
    1. Cipolletta D. Adipose tissue-resident regulatory T cells: Phenotypic specialization, functions and therapeutic potential. Immunology. 2014;142(4):517–525. - PMC - PubMed
    1. Feuerer M, et al. Lean, but not obese, fat is enriched for a unique population of regulatory T cells that affect metabolic parameters. Nat Med. 2009;15(8):930–939. - PMC - PubMed
    1. Cipolletta D, et al. PPAR-γ is a major driver of the accumulation and phenotype of adipose tissue Treg cells. Nature. 2012;486(7404):549–553. - PMC - PubMed

Publication types

MeSH terms