MOG-specific CAR Tregs: a novel approach to treat multiple sclerosis.

Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system (CNS) with the immune system attacking myelin sheaths leading to neuronal death. While several disease-modifying therapies are available to treat MS, these therapies are not universally effective and do not stop disease progression. More personalized long-term treatment options that target specific aspects of the disease, such as reducing relapse frequency, delaying disability accumulation, and addressing symptoms that impact daily functioning, as well as therapies that can promote neuroprotection and repair are needed. Chimeric Antigen Receptor (CAR) Tcell therapies have revolutionized cancer treatment by intravenously (IV) administering a defined dose of T cells with high specificity provided by the CAR. An autologous CAR T cell therapy using suppressive regulatory T cells (Tregs) inducing long-lasting tolerance would be the ideal treatment for patients. Hence, we expanded the application of CAR-T cells by introducing a CAR into Tregs to treat MS patients. We developed a myelin oligodendrocyte glycoprotein (MOG)-specific CAR Treg cell therapy for patients with MS. MOG is expressed on the outer membrane of the myelin sheath, the insulating layer the forms around nerves, making it an ideal target for CAR Treg therapy. Our lead candidate is a 2nd generation CAR, composed of an anti-MOG scFv screened from a large human library. In vitro, we demonstrated CAR-dependent functionality and showed efficacy in vivo using a passive EAE mouse model. Additionally, the MOG-CAR Tregs have very low tonic signaling with a desirable signal-to-noise ratio resulting in a highly potent CAR. In summary our data suggest that MOG-CAR Tregs are a promising MS treatment option with the potential to induce long-lasting tolerance in patients.

The Cytosolic Microbial Receptor Nod2 Regulates Small Intestinal Crypt Damage and Epithelial Regeneration following T Cell-Induced Enteropathy.

Loss of function in the NOD2 gene is associated with a higher risk of developing Crohn's disease (CD). CD is characterized by activation of T cells and activated T cells are involved in mucosal inflammation and mucosal damage. We found that acute T cell activation with anti-CD3 mAb induced stronger small intestinal mucosal damage in NOD2(-/-) mice compared with wild-type mice. This enhanced mucosal damage was characterized by loss of crypt architecture, increased epithelial cell apoptosis, delayed epithelial regeneration and an accumulation of inflammatory cytokines and Th17 cells in the small intestine. Partial microbiota depletion with antibiotics did not decrease mucosal damage 1 d after anti-CD3 mAb injection, but it significantly reduced crypt damage and inflammatory cytokine secretion in NOD2(-/-) mice 3 d after anti-CD3 mAb injection, indicating that microbial sensing by Nod2 was important to control mucosal damage and epithelial regeneration after anti-CD3 mAb injection. To determine which cells play a key role in microbial sensing and regulation of mucosal damage, we engineered mice carrying a cell-specific deletion of Nod2 in villin and Lyz2-expressing cells. T cell activation did not worsen crypt damage in mice carrying either cell-specific deletion of Nod2 compared with wild-type mice. However, increased numbers of apoptotic epithelial cells and higher expression of TNF-α and IL-22 were observed in mice carrying a deletion of Nod2 in Lyz2-expressing cells. Taken together, our results demonstrate that microbial sensing by Nod2 is an important mechanism to regulate small intestinal mucosal damage following acute T cell activation.

IL23R-specific CAR Tregs for the treatment of Crohn's disease.

BACKGROUND AND AIMS: Regulatory T cells (Tregs) are key regulators in maintaining tissue homeostasis. Disrupted immune homeostasis is associated with Crohn's disease (CD) pathogenesis. Thus, Treg therapy represents a promising long-acting treatment to restore immune balance in the diseased intestine. CAR (Chimeric Antigen Receptor) T-cell therapy has revolutionized cancer treatment. This innovative approach also provides the opportunity to improve therapy for CD. By targeting a disease-relevant protein, Interleukin-23 receptor (IL23R), we engineered Tregs expressing IL23R-CAR for treating active CD. METHODS: Intestinal IL23R expression from active CD was verified by immunohistochemical analysis. Phenotypic and functional characteristics of IL23R-CAR Tregs were assessed using in vitro assays and their migration capacity was monitored in a xenograft tumor model. Transcriptomic and proteomic analyses were performed to associate molecular profiles with IL23R-CAR Treg activation against colon biopsy-derived cells from active CD patients. RESULTS: Our study showed that IL23R-CAR displayed negligible tonic signalling and strong signal-to-noise ratio. IL23R-CAR Tregs maintained regulatory phenotype during in vitro expansion, even when chronically exposed to proinflammatory cytokines and target antigen. IL23R engagement on IL23R-CAR Tregs triggered CAR-specific activation and significantly enhanced their suppressive activity. Also, IL23R-CAR Tregs migrated to IL23R-expressing tissue in humanized mice. Finally, IL23R-CAR Tregs elicited a specific activation against colon biopsy-derived cells from active CD, suggesting an efficient CAR engagement in active CD. Molecular profiling of CD patient biopsies also revealed transcriptomic and proteomic patterns associated with IL23R-CAR activation. CONCLUSIONS: Overall, our results demonstrate that IL23R-CAR Tregs represent a promising therapy for active CD.

Type 1 regulatory T cells specific for collagen type II as an efficient cell-based therapy in arthritis.

INTRODUCTION: Regulatory T (Treg) cells play a crucial role in preventing autoimmune diseases and are an ideal target for the development of therapies designed to suppress inflammation in an antigen-specific manner. Type 1 regulatory T (Tr1) cells are defined by their capacity to produce high levels of interleukin 10 (IL-10), which contributes to their ability to suppress pathological immune responses in several settings. The aim of this study was to evaluate the therapeutic potential of collagen type II-specific Tr1 (Col-Treg) cells in two models of rheumatoid arthritis (RA) in mice. METHODS: Col-Treg clones were isolated and expanded from collagen-specific TCR transgenic mice. Their cytokine secretion profile and phenotype characterization were studied. The therapeutic potential of Col-Treg cells was evaluated after adoptive transfer in collagen-antibody- and collagen-induced arthritis models. The in vivo suppressive mechanism of Col-Treg clones on effector T-cell proliferation was also investigated. RESULTS: Col-Treg clones are characterized by their specific cytokine profile (IL-10(high)IL-4(neg)IFN-γ(int)) and mediate contact-independent immune suppression. They also share with natural Tregs high expression of GITR, CD39 and granzyme B. A single infusion of Col-Treg cells reduced the incidence and clinical symptoms of arthritis in both preventive and curative settings, with a significant impact on collagen type II antibodies. Importantly, injection of antigen-specific Tr1 cells decreased the proliferation of antigen-specific effector T cells in vivo significantly. CONCLUSIONS: Our results demonstrate the therapeutic potential of Col-Treg cells in two models of RA, providing evidence that Col-Treg could be an efficient cell-based therapy for RA patients whose disease is refractory to current treatments.