MicroRNA 10a Marks Regulatory T Cells

MicroRNAs (miRNAs) are crucial for regulatory T cell (Treg) stability and function. We report that microRNA-10a (miR-10a) is expressed in Tregs but not in other T cells including individual thymocyte subsets. Expression profiling in inbred mouse strains demonstrated that non-obese diabetic (NOD) mice with a genetic susceptibility for autoimmune diabetes have lower Treg-specific miR-10a expression than C57BL/6J autoimmune resistant mice. Inhibition of miR-10a expression in vitro leads to reduced FoxP3 expression levels and miR-10a expression is lower in unstable “exFoxP3” T cells. Unstable in vitro TGF-ß-induced, iTregs do not express miR-10a unless cultured in the presence of retinoic acid (RA) which has been associated with increased stability of iTreg, suggesting that miR-10a might play a role in stabilizing Treg. However, genetic ablation of miR-10a neither affected the number and phenotype of natural Treg nor the capacity of conventional T cells to induce FoxP3 in response to TGFβ, RA, or a combination of the two. Thus, miR-10a is selectively expressed in Treg but inhibition by antagomiRs or genetic ablation resulted in discordant effects on FoxP3

microRNA-17-92 regulates IL-10 production by regulatory T cells and control of experimental autoimmune encephalomyelitis

microRNAs (miRNA) are essential for regulatory T cell (Treg) function but little is known about the functional relevance of individual miRNA loci. We identified the miR-17-92 cluster as CD28 costimulation dependent, suggesting that it may be key for Treg development and function. Although overall immune homeostasis was maintained in mice with miR-17-92-deficient Tregs, expression of the miR-17-92 miRNA cluster was critical for Treg accumulation and function during an acute organ-specific autoimmune disease in vivo. Treg-specific loss of miR-17-92 expression resulted in exacerbated experimental autoimmune encephalitis and failure to establish clinical remission. Using peptide-MHC tetramers, we demonstrate that the miR-17-92 cluster was specifically required for the accumulation of activated Ag-specific Treg and for differentiation into IL-10-producing effector Treg

microRNA-17–92 Regulates IL-10 Production by Regulatory T Cells and Control of Experimental Autoimmune Encephalomyelitis

microRNAs (miRNA) are essential for regulatory T cell (Treg) function but little is known about the functional relevance of individual miRNA loci. We identified the miR-17–92 cluster as CD28 costimulation dependent, suggesting that it may be key for Treg development and function. Although overall immune homeostasis was maintained in mice with miR-17–92–deficient Tregs, expression of the miR-17–92 miRNA cluster was critical for Treg accumulation and function during an acute organ-specific autoimmune disease in vivo. Treg-specific loss of miR-17–92 expression resulted in exacerbated experimental autoimmune encephalitis and failure to establish clinical remission. Using peptide-MHC tetramers, we demonstrate that the miR-17–92 cluster was specifically required for the accumulation of activated Ag-specific Treg and for differentiation into IL-10–producing effector Treg

Interleukin-5-producing group 2 innate lymphoid cells control eosinophilia induced by interleukin-2 therapy.

Interleukin (IL)-2 promotes regulatory T-cell development and function, and treatment with IL-2 is being tested as therapy for some autoimmune diseases. However, patients receiving IL-2 treatment also experience eosinophilia due to an unknown mechanism. Here, we show that patients receiving low-dose IL-2 have elevated levels of serum IL-5, and this correlates with their degree of eosinophilia. In mice, low-dose IL-2-anti-IL-2 antibody complexes drove group 2 innate lymphoid cells (ILC2) to produce IL-5 and proliferate. Using genetic approaches in mice, we demonstrate that activation of ILC2 was responsible for the eosinophilia observed with IL-2 therapy. These observations reveal a novel cellular network that is activated during IL-2 treatment. A better understanding of the cross talk between these cell populations may lead to more effective targeting of IL-2 to treat autoimmune disease

The chromatin-modifying enzyme Ezh2 is critical for the maintenance of regulatory T cell identity after activation.

Regulatory T cells (Treg cells) are required for immune homeostasis. Chromatin remodeling is essential for establishing diverse cellular identities, but how the epigenetic program in Treg cells is maintained throughout the dynamic activation process remains unclear. Here we have shown that CD28 co-stimulation, an extracellular cue intrinsically required for Treg cell maintenance, induced the chromatin-modifying enzyme, Ezh2. Treg-specific ablation of Ezh2 resulted in spontaneous autoimmunity with reduced Foxp3(+) cells in non-lymphoid tissues and impaired resolution of experimental autoimmune encephalomyelitis. Utilizing a model designed to selectively deplete wild-type Treg cells in adult mice co-populated with Ezh2-deficient Treg cells, Ezh2-deficient cells were destabilized and failed to prevent autoimmunity. After activation, the transcriptome of Ezh2-deficient Treg cells was disrupted, with altered expression of Treg cell lineage genes in a pattern similar to Foxp3-deficient Treg cells. These studies reveal a critical role for Ezh2 in the maintenance of Treg cell identity during cellular activation

miR-10a expression in Treg inversely correlates with susceptibility to autoimmune disease.

<p>qRT-PCR for miR-10a expression by FACS-purified CD4⁺CD25⁺CD62L^hi Treg. a) Amplification plots for miR-10a on Treg cDNA from B6 and NOD mice. The sno202 signal for B6 and NOD completely overlapped. The signal for Tconv is comparable to miR-10a in NOD Treg (data not shown). b) Relative miR-10a expression in Treg from B6, 129X1/SvJ, 129S6/SvEvTac, DBA/2J, BALB/c and NOD/ShiLtJ mice. Bars represent means of pooled data from 3 (B6), one (129X1/SvJ), one (129S6/SvEvTac), 2 (DBA/2J), one (BALB/c) and 3 (NOD/ShiLtJ) biologic replicates. Error bars: SEM. All samples were normalized to miR-10a expression in BALB/c mice.</p

All-trans retinoic acid but not TGF-ß induces miR-10a in CD4⁺ T cells.

<p>FACS-purified CD4⁺CD62L^hiGFP^- cells from FoxP3-GFP reporter mice were cultured with plate-bound anti-CD3 and anti-CD28 antibodies +/− TGF-ß and/or retinoic acid. After 72 h the CD4⁺GFP^- and CD4⁺GFP⁺ cells were purified by flow cytometry for RNA extraction. miRNA levels were assessed by qPCR in technical triplicates. Shown is a representative experiment of two independent experiments. Error bars: SD of triplicates.</p

miR-10a marks Treg cells.

<p>qPCR analysis of relative expression of miR-10a in purified T cells. a) Thymocytes: CD4^-CD8^- double negative (DN), CD4⁺CD8⁺ double positive (DP), CD4⁺CD8^- single positive (CD4SP), CD8⁺CD4^- single positive (CD8SP), CD4⁺CD8^-FoxP3-GFP^- (CD4SP GFP^-) and CD4⁺CD8^-FoxP3-GFP⁺ (CD4 SP GFP⁺). b) CD4 SP FoxP3-GFP^-R26YFP^- (GFP^-YFP^-), CD4 SP FoxP3-GFP⁺R26YFP^- (GFP⁺YFP^-) and CD4 SP FoxP3-GFP⁺R26YFP⁺ (GFP⁺YFP⁺) thymocytes. c) CD4⁺GFP^-YFP^- (Tconv), CD4⁺GFP⁺YFP⁺ (nTreg) and CD4⁺GFP^-YFP⁺ (exFoxP3) cells purified from pooled LN and spleen. Shown is one representative experiment from four (a) and two (b, c) independent experiments. Error bars: SD of triplicates.</p