Pharmacologic Inhibition of RORγt Regulates Th17 Signature Gene Expression and Suppresses Cutaneous Inflammation In Vivo

Abstract

IL-17–producing CD4+Th17 cells, CD8+Tc17 cells, and γδ T cells play critical roles in the pathogenesis of autoimmune psoriasis. RORγt is required for the differentiation of Th17 cells and expression of IL-17. In this article, we describe a novel, potent, and selective RORγt inverse agonist (TMP778), and its inactive diastereomer (TMP776). This chemistry, for the first time to our knowledge, provides a unique and powerful set of tools to probe RORγt-dependent functions. TMP778, but not TMP776, blocked human Th17 and Tc17 cell differentiation and also acutely modulated IL-17A production and inflammatory Th17-signature gene expression (Il17a, Il17f, Il22, Il26, Ccr6, and Il23) in mature human Th17 effector/memory T cells. In addition, TMP778, but not TMP776, inhibited IL-17A production in both human and mouse γδ T cells. IL-23–induced IL-17A production was also blocked by TMP778 treatment. In vivo targeting of RORγt in mice via TMP778 administration reduced imiquimod-induced psoriasis-like cutaneous inflammation. Further, TMP778 selectively regulated Th17-signature gene expression in mononuclear cells isolated from both the blood and affected skin of psoriasis patients. In summary, to our knowledge, we are the first to demonstrate that RORγt inverse agonists: 1) inhibit Tc17 cell differentiation, as well as IL-17 production by γδ T cells and CD8+ Tc17 cells; 2) block imiquimod-induced cutaneous inflammation; 3) inhibit Th17 signature gene expression by cells isolated from psoriatic patient samples; and 4) block IL-23–induced IL-17A expression. Thus, RORγt is a tractable drug target for the treatment of cutaneous inflammatory disorders, which may afford additional therapeutic benefit over existing modalities that target only IL-17A.

RORγt+Foxp3+ Cells are an Independent Bifunctional Regulatory T Cell Lineage and Mediate Crescentic GN

“…This is of special importance because the Th17 defining transcription factor RORgt has proven to be a potent proinflammatory mediator during glomerulonephritis 20 and multiple blocking agents have been developed and await clinical testing. [25][26][27][28] Our analyses showed regular presence of biTregs in both spleens and kidneys of healthy mice. Interestingly, we observed a rapid and massive biTreg expansion early during the course of NTN which paralleled Th17 cells.…”

“…Importantly, given the dominant role of RORgt in development of pathogenic Th17 responses, multiple research groups and companies are in the process of establishing blocking agents. [25][26][27][28] Therefore it is of great interest to better characterize all cell populations expressing RORgt, especially in the light of potential clinical applications. We thus decided to study the NTN model of acute GN to address the following aspects: (1) characterize RORgt + Foxp3 + biTreg dynamics during the course of GN, (2) determine whether biTregs represent Treg17 cells, Treg/Th17 intermediates or a unique cell population, (3) investigate the functional role of biTregs in GN.…”

The role of interleukin-17 in immune-mediated inflammatory myopathies and possible therapeutic implications

“…A number of RORƴt small-molecule inhibitors have been identified and have been shown to inhibit the differentiation and function of Th17 and CD8Tc17 cells [80,126]. This approach is thought to be particularly advantageous as targeting RORƴt inhibits not only Th17 differentiation and IL-17 secretion but also the production of other proinflammatory cytokines secreted by Th17 cells.…”

An activated Th17-prone T cell subset involved in chronic graft-versus-host disease sensitive to pharmacological inhibition

“…Thus, we evaluated the in vivo cGvHD effect of pharmacological inhibition of RORγt with a small-molecule inhibitor that showed strong efficiency in other Th17-driven disease (40) and under the in vitro Th17 polarizing conditions from HD described immediately above. TMP778 interacts with RORγt to hamper its transcription factor activity and, consequently, IL-17 secretion (40,41). Toward clinical translation, we treated recipients with TMP778 beginning on day 28 (d28) at the time of established cGvHD.…”

“…One such small-molecule RORγt inhibitor is TMP778, which acts through several modalities: interruption of RORγt binding its target genes, disrupting RORγt interaction with other transcription factors or coactivators, and promotion of Gata3 transactivation (40). Previous reports demonstrated the role of TMP778 interfering with Th17 cell differentiation and its activity during mouse models of autoimmune diseases (40,41). Molecular studies showing a STAT3-dependent mechanism of action suggest RORγt inhibitor use as a candidate treatment of cGvHD.…”