Th17 Differentiation In Mice Research Articles

The Transcription Factor ELF4 Restrains the Inflammatory Potential of CD4+ T Cells

Abstract ELF4 is a member of the ETS family of transcription factors, known to be involved in the regulation and development of immune cells. Yet, the primary function of ELF4 was unknown prior to our discovery of patients with loss-of-function mutations in ELF4 that cause the monogenic autoinflammatory disease Deficiency in ELF4, X-linked (DEX), driven by aberrant inflammation. While it has been demonstrated by our lab that global loss of ELF4 results in hyper-cytokine release in macrophages and restrains Th17 differentiation in mice, the breadth and mechanisms of CD4+ T cell regulation by ELF4 remain enigmatic. Here, we show that loss of T cell-intrinsic ELF4 leads to enhanced interferon gamma and IL-17A production upon activation of naïve CD4+ T cells and demonstrate modulation of CD4+ T cell cytokine production by ELF4 is independent of its presence during T cell development as well as extrinsic signaling in vivo. Further, absence of T cell-intrinsic ELF4 leads to decreased expression of ATF4, a master regulator of the integrated stress response demonstrated to be crucial in restraining cytokine release upon initial activation of naïve T cells. Notably, we found ELF4 binds to the promoter region of ATF4, and expression of ATF4-induced genes is significantly reduced in CD4+ T cells in the absence of ELF4 post-activation. Thus, we elucidate an essential mechanism for restraining CD4+ T cell inflammatory potential dependent on regulation of the integrated stress response by ELF4.

Sirtuin-1 Activation Controls Tumor Growth by Impeding Th17 Differentiation via STAT3 Deacetylation

Sirtuin-1 deacetylates proteins and has emerged asacritical regulator of different cellular processes, particularly inflammation. Basal SIRT1 activity was previously found to limit Th9 and enhance Th17 differentiation in mice, but the effect of pharmacological SIRT1 activation on Tcell differentiation and antitumor responses remains unclear. Here, we find that SIRT1 pharmacological agonists selectively impede mouse and human Th17 cell differentiation. SIRT1activation induces STAT3 deacetylation, thus reducing its ability to translocate into the nucleus, bind to Rorc promoter, and induce its transcription. SIRT1 agonists reduce tumor growth in mice by blocking Th17 cell differentiation. In cancer patients, the SIRT1 agonist metformin reduced the frequency of Th17 cells and STAT3 acetylation levels. Altogether, these data underscore that SIRT1 activation impedes Th17 cell differentiation and thereby limits tumor growth and suggest that SIRT1 activators may directly target IL-17A functions.

Disulfiram and Diphenhydramine Hydrochloride Upregulate miR-30a to Suppress IL-17-Associated Autoimmune Inflammation.

T-helper 17 (Th17) cells play an important role in the pathogenesis of multiple sclerosis (MS), an autoimmune demyelinating disease that affects the CNS. In the present study, MicroRNA sequencing (miRNA-seq) was performed in mouse Th0 and Th17 cells to determine the critical miRNAs that are related to Th17 differentiation. We found that miR-30a was significantly downregulated during mouse Th17 differentiation. In addition, the level of miR-30a in CD4(+) T cells from peripheral blood of MS patients and experimental autoimmune encephalomyelitis (EAE) animal models was also decreased and inversely correlated with the expression of interleukin 17a, the canonical cytokine of Th17 cells. Moreover, overexpression of miR-30a inhibited Th17 differentiation and prevented the full development of EAE, whereas interference of miR-30a promoted Th17 differentiation. Mechanism studies showed that miR-30a reduced IRF4 expression by specifically binding with the 3'-untranslated region. Through screening of 640 different Food and Drug Administration (FDA)-approved drugs, we found that disulfiram and diphenhydramine hydrochloride were effective candidates for inhibiting Th17 differentiation and ameliorating EAE development through upregulating miR-30a. To our knowledge, the present work is not only the first miRNA-seq study focusing on Th17 differentiation, but also the first chemical screening for FDA-approved drugs that inhibit Th17 differentiation through regulating miRNA expression. The present work is the first miRNA sequencing (miRNA-seq) study focusing on T-helper 17 (Th17) differentiation. By miRNA deep sequencing, we found that miR-30a was downregulated during Th17 differentiation. miR-30a was also decreased in CD4(+) T cells from multiple sclerosis patients and experimental autoimmune encephalomyelitis (EAE) mice. miR-30a reduced IRF4 expression by specific binding with the 3'-untranslated region and thus suppressed Th17 differentiation and prevented the full development of EAE. Interestingly, by performing a chemical screen with Food and Drug Administration-approved small-molecule drugs, we found that disulfiram and diphenhydramine upregulated miR-30a and suppressed Th17-associated autoimmune demyelination.

Th17 cytokine differentiation and loss of plasticity after SOCS1 inactivation in a cutaneous T-cell lymphoma.

We propose that deregulated T-helper-cell (Th) signaling underlies evolving Th17 cytokine expression seen during progression of cutaneous T-cell lymphoma (CTCL). Accordingly, we developed a lymphoma progression model comprising cell lines established at indolent (MAC-1) and aggressive (MAC-2A) CTCL stages. We discovered activating JAK3 (V722I) mutations present at indolent disease, reinforced in aggressive disease by novel compound heterozygous SOCS1 (G78R/D105N) JAK-binding domain inactivating mutations. Though isogenic, indolent and aggressive-stage cell lines had diverged phenotypically, the latter expressing multiple Th17 related cytokines, the former a narrower profile. Importantly, indolent stage cells remained poised for Th17 cytokine expression, readily inducible by treatment with IL-2 - a cytokine which mitigates Th17 differentiation in mice. In indolent stage cells JAK3 expression was boosted by IL-2 treatment. Th17 conversion of MAC-1 cells by IL-2 was blocked by pharmacological inhibition of JAK3 or STAT5, implicating IL2RG - JAK3 – STAT5 signaling in plasticity responses. Like IL-2 treatment, SOCS1 knockdown drove indolent stage cells to mimic key aggressive stage properties, notably IL17F upregulation. Co-immunoprecipitation experiments showed that SOCS1 mutations abolished JAK3 binding, revealing a key role for SOCS1 in regulating JAK3/STAT5 signaling. Collectively, our results show how JAK/STAT pathway mutations contribute to disease progression in CTCL cells by potentiating inflammatory cytokine signaling, widening the potential therapeutic target range for this intractable entity. MAC-1/2A cells also provide a candidate human Th17 laboratory model for identifying potentally actionable CTCL markers or targets and testing their druggability in vitro.

Suppression of human and mouse Th17 differentiation and autoimmunity by an endogenous Interleukin 23 receptor cytokine-binding homology region

T-helper 17 (Th17) cells, a recently identified CD4+ T subset with a unique characteristic to produce Interleukin-17 (IL-17), are critical for the development of autoimmune diseases such as multiple sclerosis, in which IL-23 plays an important role in the differentiation of Th17 cells through IL-23/IL-23-receptor/STAT3 pathway. Previously, soluble recombinant human IL-23 receptor cytokine-binding homology region (hIL23R-CHR) was constructed in our laboratory to neutralize IL-23 and inhibit murine Th17 development in vitro. Herein we present that hIL23R-CHR could inhibit both differentiation and function of human/murine Th17 cells. The present in vivo study further demonstrated that hIL23R-CHR inhibited murine Th17 cell development by down regulating IL-17 gene expression and protected mice against the development of experimental autoimmune encephalomyelitis (EAE) through suppression of CNS inflammation and pro-inflammatory cytokine production. In addition to the in vitro inhibition of human Th17 cells in a dose-dependent manner, the antagonizing effect of hIL23R-CHR was confirmed by reduced levels of IL-23 in both blood and brain of EAE mice and STAT3 phosphorylation in vivo. Taken together, our data demonstrated that hIL23R-CHR could be an effective and specific immunosuppressive molecule for the treatment of Th17-related autoimmune diseases.

CD30 Ligand/CD30 Plays a Critical Role in Th17 Differentiation in Mice

A CD30 ligand (CD30L; CD153) and its receptor, CD30, is a membrane-associated glycoprotein belonging to the TNF superfamily and TNFR superfamily. These were expressed preferentially by activated CD4(+)T cells. In this paper, we show that CD44(low)CD62(hi)CD4(+) T cells from CD30L(-/-) or CD30(-/-) mice exhibited impaired differentiation into Th17 cells but an increased ability to produce IL-2 after in vitro culture under Th17-polarizing conditions. Neutralization with IL-2 by anti-IL-2 mAb partly restored the ability of Th17 differentiation in CD30L(-/-) or CD30(-/-) T cells. Stimulation via CD30L by immobilized anti-CD30L mAb suppressed IL-2 production by CD30(-/-)CD4(+) T cells, indicating that the reverse signal to CD30L is responsible for downregulation of IL-2 production. In vivo Th17 differentiation of CD30L(-/-)CD4(+)CD45RB(high) T cells was also impaired after transfer into SCID mice, whereas CD30L(+/+)CD4(+)CD45RB(high) T cells normally differentiated into Th17 cells in CD30L(-/-) SCID mice. The results of these studies demonstrate that CD30L/CD30 signaling executed by the T-T cell interaction plays a critical role in Th17 cell differentiation, at least partly via downregulation of IL-2 production.

IL-6-independent arthritis and Th17 differentiation in mice

IL-6-independent arthritis and Th17 differentiation in mice

The nuclear receptor PPARγ selectively inhibits Th17 differentiation in a T cell–intrinsic fashion and suppresses CNS autoimmunity

T helper cells secreting interleukin (IL)-17 (Th17 cells) play a crucial role in autoimmune diseases like multiple sclerosis (MS). Th17 differentiation, which is induced by a combination of transforming growth factor (TGF)-β/IL-6 or IL-21, requires expression of the transcription factor retinoic acid receptor–related orphan receptor γt (RORγt). We identify the nuclear receptor peroxisome proliferator–activated receptor γ (PPARγ) as a key negative regulator of human and mouse Th17 differentiation. PPARγ activation in CD4+ T cells selectively suppressed Th17 differentiation, but not differentiation into Th1, Th2, or regulatory T cells. Control of Th17 differentiation by PPARγ involved inhibition of TGF-β/IL-6–induced expression of RORγt in T cells. Pharmacologic activation of PPARγ prevented removal of the silencing mediator for retinoid and thyroid hormone receptors corepressor from the RORγt promoter in T cells, thus interfering with RORγt transcription. Both T cell–specific PPARγ knockout and endogenous ligand activation revealed the physiological role of PPARγ for continuous T cell–intrinsic control of Th17 differentiation and development of autoimmunity. Importantly, human CD4+ T cells from healthy controls and MS patients were strongly susceptible to PPARγ-mediated suppression of Th17 differentiation. In summary, we report a PPARγ-mediated T cell–intrinsic molecular mechanism that selectively controls Th17 differentiation in mice and in humans and that is amenable to pharmacologic modulation. We therefore propose that PPARγ represents a promising molecular target for specific immunointervention in Th17-mediated autoimmune diseases such as MS.