Regulatory T cells in dominant immunologic tolerance

Epigenetically Reprogrammed Nanovesicles as Inverse Vaccines for Antigen-Specific Immune Tolerance in Autoimmune Diseases

The development of antigen-specific immunotherapy for autoimmune diseases constitutes an important unmet clinical need. Here we present an innovative inverse vaccine platform leveraging epigenetic reprogramming to induce durable antigen-specific immune tolerance. This inverse vaccine (mDCNVreg) is constructed using artificial cell membrane nanovesicles derived from IFN-γ-primed regulatory dendritic cells subjected to epigenetic modulation. The engineered mDCNVreg features upregulated MHC-II expression enabling targeted antigen presentation, suppressed costimulatory molecules expression, and an enhanced coinhibitory molecules display. Through coordinated mechanisms involving enhanced lymphoid trafficking and phenotype stabilization, this platform significantly enhances antigen delivery to secondary lymphoid organs while maintaining tolerogenic potency. Crucially, mDCNVreg directly induces CD4+ T cell clonal anergy through epitope-specific interactions, establishing long-lasting immune tolerance. This work demonstrates a promising epigenetic engineering approach for reverse vaccine design in personalized autoimmune disease therapy.

Genetic and epigenetic regulation of Treg cell fitness by autism-related chromatin remodeler CHD8

BACKGROUND

Chromatin remodeler chromodomain helicase DNA-binding protein 8 (CHD8) defines a subtype of autism that is associated with immune disorders. It remains unknown whether CHD8 plays a cell-intrinsic role in immune cells such as regulatory T cells (Tregs) that maintain immune tolerance through suppressing CD4+ and CD8+ effector T cells.

METHODS

Treg-specific conditional CHD8-deficient mice were generated by crossing Chd8Flox/Flox mice with Foxp3YFP-cre transgenic mice. Effects of CHD8 deficiency were investigated using hematoxylin and eosin (H&E) staining, flow cytometry, and multi-omics, including RNA-sequencing (RNA-seq), assay for transposase-accessible chromatin sequencing (ATAC-seq), and chromatin immunoprecipitation sequencing (CHIP-seq).

RESULTS

We found that Treg-specific CHD8 deletion led to early, fatal inflammation owing to increased CD4+ and CD8+ effector T cells. CHD8 deletion did not alter Treg homeostasis but increased their functional plasticity with elevated expression of effector T cell cytokines. CHIP-seq of Tregs uncovered that CHD8 binding genes were enriched in phosphatidylinositol-3 kinase (PI3K)-protein kinase B (Akt)-mammalian target of rapamycin (mTOR) signaling and several other pathways. RNA-seq and ATAC-seq revealed that CHD8 deletion upregulated a number of pathways, notably mammalian target of rapamycin complex 1 (mTORC1) signaling and its mediated glycolysis that have been reported to promote Treg plasticity. Integrating RNA-seq data with CHIP-seq and ATAC-seq data identified a number of CHD8 target genes whose expression depends on CHD8 direct binding-mediated chromatin remodeling.

CONCLUSIONS

Our findings suggest that CHD8 plays an important role in maintaining Treg fitness through genetic and epigenetic mechanisms to control autoimmunity, which may have important implications in immune changes in autism.

Notch4 regulatory T cells and SARS-CoV-2 viremia shape COVID19 survival outcome

BACKGROUND

Immune dysregulation and SARS-CoV-2 plasma viremia have been implicated in fatal COVID-19 disease. However, how these two factors interact to shape disease outcomes is unclear.

METHODS

We carried out viral and immunological phenotyping on a prospective cohort of 280 patients with COVID-19 presenting to acute care hospitals in Boston, Massachusetts and Genoa, Italy between June 1, 2020 and February 8, 2022. Disease severity, mortality, plasma viremia, and immune dysregulation were assessed. A mouse model of lethal H1N1 influenza infection was used to analyze the therapeutic potential of Notch4 and pyroptosis inhibition in disease outcome.

RESULTS

Stratifying patients based on %Notch4+ Treg cells and/or the presence of plasma viremia identified four subgroups with different clinical trajectories and immune phenotypes. Patients with both high %Notch4+ Treg cells and viremia suffered the most disease severity and 90-day mortality compared to the other groups even after adjusting for baseline comorbidities. Increased Notch4 and plasma viremia impacted different arms of the immune response in SARS-CoV-2 infection. Increased Notch4 was associated with decreased Treg cell amphiregulin expression and suppressive function whereas plasma viremia was associated with increased monocyte cell pyroptosis. Combinatorial therapies using Notch4 blockade and pyroptosis inhibition induced stepwise protection against mortality in a mouse model of lethal H1N1 influenza infection.

CONCLUSIONS

The clinical trajectory and survival outcome in hospitalized patients with COVID-19 is predicated on two cardinal factors in disease pathogenesis: viremia and Notch4+ Treg cells. Intervention strategies aimed at resetting the immune dysregulation in COVID-19 by antagonizing Notch4 and pyroptosis may be effective in severe cases of viral lung infection.

Interleukin-38-overexpressing adenovirus infection in dendritic cell-based treatment enhances immunotherapy for allergic asthma via inducing Foxp3+ regulatory T cells

Allergic asthma is a chronic disease tied to unusual immune reactions involving type 2 T helper (Th2) cells specific to allergens. Dendritic cells (DCs) play a crucial role in guiding T-cell responses. Regulatory T (Treg) cells have the ability to suppress effector T-cell responses, and interleukin (IL)-38 is involved in Treg cell differentiation. In this study, we explored impacts of IL-38 on the activation and function of DCs, and we then developed an IL-38-overexpressing adenovirus (Ad-IL38) to evaluate its effectiveness in treating allergic asthma in mice through the adaptive transfer of Ad-IL38-infected DCs (IL38-DCs). Treating lipopolysaccharide (LPS)-activated bone marrow-derived DCs with recombinant IL-38 reduced cluster of differentiation 80 (CD80), CD86, and major histocompatibility complex (MHC) II expressions and decreased IL-1β, IL-6, and tumor necrosis factor (TNF)-α while increasing IL-10 secretion. The simultaneous culture of these semi-mature DCs with allogeneic CD4+ T cells facilitated the production of Forkhead box protein P3-positive (Foxp3+) Treg cells. A transcriptomic analysis revealed downregulation of the Chil3, Inhba, and Ctgf genes that are crucial for regulating inflammatory responses and cytokine-mediated signaling pathways in IL-38-treated DCs. In an animal model of asthma, IL38-DC treatment effectively decreased levels of an ovalbumin (OVA)-specific immunoglobulin E (IgE) antibody in serum, attenuated the severity of airway hyperresponsiveness, reduced the production of Th2-type cytokines (IL-4, IL-5, and IL-13) and proinflammatory cytokines (IL-6 and TNF-α) in bronchoalveolar lavage fluid, lowered expressions of the Th2-related cytokines IL-25 and thymic stromal-derived lymphopoietin (TSLP) by lung epithelial cells, and mitigated airway inflammation. Notably, enhanced expression of Foxp3+ Treg cells was linked to increased mRNA levels of transforming growth factor (TGF)-β production in vivo. In conclusion, we comprehensively clarified the immunomodulatory effects of IL-38 on DCs and provide a new treatment with IL-38 genetically modified DCs for alleviating Th2-mediated allergic diseases.

Development of Hypoallergenic Derivatives of Cra a 1 with B Cell Epitope Deletion and T Cell Epitope Retention

Tropomyosin was reported as an important allergen in Crassostrea angulata and designated as Cra a 1. The localization of the T cell epitopes and the reduction of the immunoreactivity of Cra a 1 are still lacking. In this study, four T cell epitopes were identified by using wild-type Cra a 1 (wtCra a 1)-immunized mouse splenocytes cultured with synthetic peptides. The immunoreactivity was maintained after chemical denaturation treatment, indicating that the linear epitope is an immunodominant epitope of wtCra a 1. Furthermore, the hypoallergenic derivative (mCra a 1) was developed by the deletion of linear B cell epitopes and retention of T cell epitopes. mCra a 1 could stimulate CD4+T cell proliferation and upregulate interleukin-10 secretion. Overall, basophil activation by mCra a 1 was low, but its ability to induce T cell proliferation was retained, suggesting that mCra a 1 may serve as a viable candidate for treating oyster allergy.

Deciphering the developmental trajectory of tissue-resident Foxp3+ regulatory T cells

Foxp3+ TREG cells have been at the focus of intense investigation for their recognized roles in preventing autoimmunity, facilitating tissue recuperation following injury, and orchestrating a tolerance to innocuous non-self-antigens. To perform these critical tasks, TREG cells undergo deep epigenetic, transcriptional, and post-transcriptional changes that allow them to adapt to conditions found in tissues both at steady-state and during inflammation. The path leading TREG cells to express these tissue-specialized phenotypes begins during thymic development, and is further driven by epigenetic and transcriptional modifications following TCR engagement and polarizing signals in the periphery. However, this process is highly regulated and requires TREG cells to adopt strategies to avoid losing their regulatory program altogether. Here, we review the origins of tissue-resident TREG cells, from their thymic and peripheral development to the transcriptional regulators involved in their tissue residency program. In addition, we discuss the distinct signalling pathways that engage the inflammatory adaptation of tissue-resident TREG cells, and how they relate to their ability to recognize tissue and pathogen-derived danger signals.