TGF-ß controls development of TCRγδ+CD8αα+ intestinal intraepithelial lymphocytes.

γδ intestinal intraepithelial lymphocytes (IELs) constitute the majority of IELs with unique CD8αα+ homodimers that are distinct from γδT cells in other tissues. However, it remains largely unclear how those cells develop. Here we show that transforming growth factor beta (TGF-ß) signaling controls the development of TCRγδ+CD8αα+ IELs. Deletion of TGF-ß receptors or Smad3 and Smad2 in bone marrow stem cells caused a deficiency of TCRγδ+CD8αα+ IELs in mixed bone marrow chimeric mice. Mechanistically, TGF-ß is required for the development of TCRγδ+CD8αα+ IELs thymic precursors (CD44-CD25- γδ thymocytes). In addition, TGF-ß signaling induced CD8α in thymic γδT cells and maintained CD8α expression and survival in TCRγδ+CD8αα+ IELs. Moreover, TGF-ß also indirectly controls TCRγδ+CD8αα+ IELs by modulating the function of intestinal epithelial cells (IECs). Importantly, TGF-ß signaling in TCRγδ+CD8αα+ IELs safeguarded the integrity of the intestinal barrier in dextran sulfate sodium (DSS)-induced colitis.

TGF-ß uncouples glycolysis and inflammation in macrophages and controls survival during sepsis.

Changes in metabolism of macrophages are required to sustain macrophage activation in response to different stimuli. We showed that the cytokine TGF-ß (transforming growth factor-ß) regulates glycolysis in macrophages independently of inflammatory cytokine production and affects survival in mouse models of sepsis. During macrophage activation, TGF-ß increased the expression and activity of the glycolytic enzyme PFKL (phosphofructokinase-1 liver type) and promoted glycolysis but suppressed the production of proinflammatory cytokines. The increase in glycolysis was mediated by an mTOR-c-MYC-dependent pathway, whereas the inhibition of cytokine production was due to activation of the transcriptional coactivator SMAD3 and suppression of the activity of the proinflammatory transcription factors AP-1, NF-κB, and STAT1. In mice with LPS-induced endotoxemia and experimentally induced sepsis, the TGF-ß-induced enhancement in macrophage glycolysis led to decreased survival, which was associated with increased blood coagulation. Analysis of septic patient cohorts revealed that the expression of PFKL, TGFBRI (which encodes a TGF-ß receptor), and F13A1 (which encodes a coagulation factor) in myeloid cells positively correlated with COVID-19 disease. Thus, these results suggest that TGF-ß is a critical regulator of macrophage metabolism and could be a therapeutic target in patients with sepsis.

In Vivo Generation of SSA/Ro Antigen-Specific Regulatory T Cells Improves Experimental Sjögren's Syndrome in Mice.

OBJECTIVE: Sjögren's syndrome (SS) is a systemic autoimmune disease, and T cells play an important role in the initiation and perpetuation of the disease. In this study, we developed an immunotherapy for NOD/LtJ mice with SS-like symptoms by combining a transient depletion of CD4+ T cells with the administration of autoantigen-specific peptide Ro480. METHODS: NOD/LtJ mice were treated with single anti-CD4 monoclonal antibody (mAb) followed 2 days later by a series of 6 intraperitoneal injections of Ro480-494 every other day. Salivary flow rates were determined pre- and posttreatment once a week. Mice were euthanized 6 weeks after the initial anti-CD4 mAb treatment, salivary glands (SGs) were collected for analyses of histologic disease scores and inflammatory cell infiltration, polymerase chain reaction determination of genes was conducted, and flow cytometry analysis including major histocompatibility complex class II tetramer staining of immune cells was performed. In addition, adoptive transfer of Treg cells was administrated to investigate the function of the newly generating Treg cells in vivo. RESULTS: The combination of anti-CD4 mAb with autoantigen-specific peptide Ro480 generated SSA/Ro antigen-specific Treg cells in vivo, which can suppress interferon-γ production of CD4+ T cells and inflammation infiltration in SGs and maintain the function of SGs. CONCLUSION: Our findings provide a new approach to generating antigen-specific Treg cells in vivo for SS treatment, which may have implications for potential therapy for patients with SS.

Adipose-mesenchymal stromal cells suppress experimental Sjögren syndrome by IL-33-driven expansion of ST2+ regulatory T cells.

Adipose-derived mesenchymal stromal cells (ADSCs) play important roles in the alleviation of inflammation and autoimmune diseases. Interleukin-33 (IL-33), a member of the IL-1 family, has been shown to regulate innate and adaptive immunity. However, it is still unknown whether ADSCs regulate immune responses via IL-33. We show here that ADSCs produced IL-33 in response to IL-1ß stimulation, which depended on TAK1, ERK, and p38 pathways. ADSCs-derived IL-33 drove the proliferation of CD4+Foxp3+ST2+ regulatory T cells (Tregs) and alleviated experimental autoimmune Sjögren syndrome in mice. Importantly, human ADSCs also produced IL-33 in response to IL-1ß. Thus, we have revealed a previously unrecognized immunoregulatory function of ADSCs by IL-33 production in experimental autoimmunity, which may have clinical applications for human immunopathology.