Graphical abstract

The intestinal immune system is constantly challenged by commensal bacteria; therefore, it must maintain quiescence via several regulatory mechanisms. Although intestinal macrophages (Mϕs) have been implicated in repression of excessive inflammation, it remains unclear how their functions are regulated during inflammation. In this study, we report that semaphorin 7A (Sema7A), a GPI-anchored semaphorin expressed in intestinal epithelial cells (IECs), induces IL-10 production by intestinal Mφs to regulate intestinal inflammation. Sema7A-deficient mice showed severe signs of dextran sodium sulfate-induced colitis due to reduced intestinal IL-10 levels. We further identified CX3CR1+MHC class IIintF4/80hiCD11bhi Mφs as the main producers of IL-10 via αvβ1 integrin in response to Sema7A. Notably, Sema7A was predominantly expressed on the basolateral side of IECs, and its expression pattern was responsible for protective effects against dextran sodium sulfate-induced colitis and IL-10 production by Mφs during interactions between IECs and Mφs. Furthermore, we determined that the administration of recombinant Sema7A proteins ameliorated the severity of colitis, and these effects were diminished by IL-10–blocking Abs. Therefore, our findings not only indicate that Sema7A plays crucial roles in suppressing intestinal inflammation through αvβ1 integrin, but also provide a novel mode of IL-10 induction via interactions between IECs and Mφs.

Cancer immunotherapy using chimeric antigen receptor-armed T (CAR T) cells have been shown to improve outcomes significantly in patients with hematological malignancies. However, cytokine release syndrome (CRS) remains a risk. CRS is characterized by the excessive activation of CAR T cells and macrophages. Signs and symptoms of CRS are usually resolved after steroid administration, but steroids abrogate the expansion and persistence of CAR T cell populations. Tocilizumab is a humanized monoclonal antibody (mAb) that attenuates CRS without significant loss of CAR T cell activity. However, interleukin-6 (IL-6)/ IL-6 receptor (IL-6R) blockade alone cannot relieve CRS symptoms fully, and novel treatments are needed to prevent or cure CRS. TO-207 is an N-benzoyl-L-phenylalanine derivative that significantly inhibits inflammatory cytokine production in human monocyte and macrophage-specific manner. We investigated whether TO-207 could inhibit cytokine production without impairing CAR T cell function in a CRS-simulating co-culture system.

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Background: Stimulation with antigen and IgE is known to activate NF-κB in mast cells. In the present research, we studied the role of NF-κB on cellular migration in mast cell-like RBL-2H3 cells and bone marrow-derived mast cells (BMMCs) using the NF-κB inhibitor (-)-DHMEQ. Methods: A Matrigel invasion chamber was used to evaluate cell migration. A PCR array was used to screen the expression of 84 key genes involved in cell migration. Results: (-)-DHMEQ inhibited antigen/IgE-induced NF-κB activation and expressions of its target genes such as IL-6 and TNF-α. (-)-DHMEQ was found to inhibit in vitro invasion toward the antigen without any toxicity. We then looked for NF-κB-dependent genes that would be important for mast cell invasion using the PCR array. (-)-DHMEQ was found to lower the expression of matrix metalloproteinase (MMP)-2. The MMP inhibitor GM6001 also inhibited cellular invasion toward the antigen. These effects of (-)-DHMEQ were obtained in both RBL-2H3 cells and BMMCs. Conclusions: These findings indicate that (-)-DHMEQ suppressed mast cell migration via the inhibition of NF-κB-regulated MMP-2 expression.