TIPE2 deficiency prolongs mouse heart allograft survival by facilitating immature DCs-induced Treg generation.

It has been reported that deletion of tumor necrosis factor-α-induced protein-8 like 2 (TNFAIP8L2, TIPE2) facilitates the activation of T-cell receptors. However, the role of TIPE2 in T-cell-mediated acute transplant rejection remains unclear. To illustrate the underlying cellular mechanisms, we transplanted BALB/c hearts into C57BL/6 wild-type (WT) or C57BL/6 mice deficient for TIPE2 (TIPE2-/-) and found that TIPE2-/- recipient mice showed significantly prolonged survival of heart allografts and suppressed maturation of CD11c+ dendritic cells (DCs), which largely abolished the activation and proliferation of alloreactive T cells and their cytotoxic activity. TIPE2-/- DCs increased CD4+CD25+Foxp3+CD127- regulatory T cells (Tregs)generation, likely by inhibiting DCs maturation and CD80 and CD86 expression. Administration of anti-CD25 abolished the allograft survival induced by TIPE2 deficiency. Moreover, TIPE2 deficiency increased IL-10 production in T cells and in recipient serum and allografts. Mechanistic studies revealed that TIPE2-/- restrained the maturation of DCs via inhibition of PI3K/AKT phosphorylation during alloantigen stimulation. Taken together, TIPE2 deficiency in recipient mice inhibited acute rejection by increasing Tregs generated by immature DCs. Thus, TIPE2 could be a therapeutic target for suppressing rejection in organ transplantation.

TIPE2 knockout reduces myocardial cell damage by inhibiting IFN-γ-mediated ferroptosis.

Acute rejection of the transplanted heart is mediated by oxidative programmed cell death through the synergistic effects of the innate and adaptive immune systems. However, the role of ferroptosis, a newly discovered form of oxidative cell death, has not been widely evaluated. Tumor necrosis factor-α-induced protein-8 like 2 (TNFAIP8L2), also known as TIPE2, is required for maintaining immune homeostasis. To characterize the role of TIPE2 in mediating heart allografts, BALB/c hearts were transplanted into C57BL/6 wild-type (WT) and TIPE2-/- recipient mice. In TIPE2-/- recipient mice, allograft injury in BALB/c allograft hearts was significantly reduced through the inhibition of allograft ferroptosis. On day 3 and day 6 post-transplantation, the numbers of CD3+, CD4+, and CD8+ cells among splenocytes and draining lymph node cells were significantly decreased, and the activation of CD4+ and CD8+ cells in grafts was decreased in TIPE2-/- recipient mice compared with WT mice. Moreover, CD4+ and CD8+ T cells in TIPE2-/- recipient mice were characterized by deficient capacities for interferon-γ (IFN-γ) production through the TBK1 signaling axis and increased glutathione peroxidase 4 (GPX4). In cell experiments, treatment with IFN-γ enhanced ferroptosis-specific lipid peroxidation in myocardial cells and correlated inversely with GPX4 expression. Mechanistically, IFN-γ administration decreased the expression of GPX4 by inhibiting MEK/ERK phosphorylation. In summary, our findings demonstrated that TIPE2 deficiency inhibits T-cell production of IFN-γ to reduce ferroptosis in allografts by restraining lipid peroxidation.

MSI2 deficiency in ILC3s attenuates DSS-induced colitis by affecting the intestinal microbiota.

Background: The etiology and pathogenesis of inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are generally believed to be related to immune dysfunction and intestinal microbiota disorder. However, the exact mechanism is not yet fully understood. The pathological changes associated with dextran sodium sulfate (DSS)-induced colitis are similar to those in human UC. As a subgroup of the innate immune system, group 3 innate lymphoid cells (ILC3s) are widely distributed in the lamina propria of the intestinal mucosa, and their function can be regulated by a variety of molecules. Musashi2 (MSI2) is a type of evolutionarily conserved RNA-binding protein that maintains the function of various tissue stem cells and is essential for postintestinal epithelial regeneration. The effect of MSI2 deficiency in ILC3s on IBD has not been reported. Thus, mice with conditional MSI2 knockout in ILC3s were used to construct a DSS-induced colitis model and explore its effects on the pathogenesis of IBD and the species, quantity and function of the intestinal microbiota. Methods: Msi2flox/flox mice (Msi2fl/fl ) and Msi2flox/floxRorcCre mice (Msi2ΔRorc ) were induced by DSS to establish the IBD model. The severity of colitis was evaluated by five measurements: body weight percentage, disease activity index, colon shortening degree, histopathological score and routine blood examination. The species, quantity and function of the intestinal microbiota were characterized by high-throughput 16S rRNA gene sequencing of DNA extracted from fecal samples. Results: MSI2 was knocked out in the ILC3s of Msi2ΔRorc mice. The Msi2ΔRorc mice exhibited reductions in body weight loss, the disease activity index, degree of colon shortening, tissue histopathological score and immune cells in the peripheral blood compared to those of Msi2fl/fl mice after DSS administration. The 16S rRNA sequencing results showed that the diversity of the intestinal microbiota in DSS-treated Msi2ΔRorc mice changed, with the abundance of Firmicutes increasing and that of Bacteroidetes decreasing. The linear discriminant analysis effect size (LEfSe) approach revealed that Lactobacillaceae could be the key bacteria in the Msi2ΔRorc mouse during the improvement of colitis. Using PICRUST2 to predict the function of the intestinal microbiota, it was found that the functions of differential bacteria inferred by modeling were mainly enriched in infectious diseases, immune system and metabolic functions. Conclusions: MSI2 deficiency in ILC3s attenuated DSS-induced colonic inflammation in mice and affected intestinal microbiota diversity, composition, and function, with Lactobacillaceae belonging to the phylum Firmicutes possibly representing the key bacteria. This finding could contribute to our understanding of the pathogenesis of IBD and provide new insights for its clinical diagnosis and treatment.

Poly[bis-{µ-N'-[(pyridin-4-yl)methyl-idene]benzohydrazidato}copper(II)].

In the title complex, [Cu(C13H10N3O)2] n , the copper(II) cation is located on a crystallographic inversion centre and adopts an elongated octa-hedral coordination geometry with the equatorial plane provided by trans-arranged bis-N,O-chelating acyl-hydrazine groups from two ligands and the apices by the N atoms of two pyridine rings belonging to symmetry-related ligands. The ligand adopts a Z conformation about the C=N double bond. The dihedral angle between the pyridine and phenyl rings is 2.99 (13)°. An intra-ligand C-H⋯N hydrogen bond is observed. In the crystal, each ligand bridges two adjacent metal ions, forming a (4,4) grid layered structure. π-π stacking inter-actions [centroid-centroid distances in the range 3.569 (4)-3.584 (9) Å] involving rings of adjacent layers result in the formation of a three-dimensional supra-molecular network.