Immunometabolism is critical in the regulation of immunity and inflammation; however, the mechanism of preventing aberrant activation-induced immunopathology remains largely unclear. Here, we report that glyoxalase II (GLO2) in the glycolysis branching pathway is specifically downregulated by NF-κB signaling during innate immune activation via tristetraprolin (TTP)-mediated mRNA decay. As a result, its substrate S-D-lactoylglutathione (SLG) accumulates in the cytosol and directly induces D-lactyllysine modification of proteins. This nonenzymatic lactylation by SLG is greatly facilitated by a nearby cysteine residue, as it initially reacts with SLG to form a reversible S-lactylated thiol intermediate, followed by SN-transfer of the lactyl moiety to a proximal lysine. Lactylome profiling identifies 2255 lactylation sites mostly in cytosolic proteins of activated macrophages, and global protein structure analysis suggests that proximity to a cysteine residue determines the susceptibility of lysine to SLG-mediated D-lactylation. Furthermore, lactylation is preferentially enriched in proteins involved in immune activation and inflammatory pathways, and D-lactylation at lysine 310 (K310) of RelA attenuates inflammatory signaling and NF-κB transcriptional activity to restore immune homeostasis. Accordingly, TTP-binding site mutation or overexpression of GLO2 in vivo blocks this feedback lactylation in innate immune cells and promotes inflammation, whereas genetic deficiency or pharmacological inhibition of GLO2 restricts immune activation and attenuates inflammatory immunopathology both in vitro and in vivo. Importantly, dysregulation of the GLO2/SLG/D-lactylation regulatory axis is closely associated with human inflammatory phenotypes. Overall, our findings uncover an immunometabolic feedback loop of SLG-induced nonenzymatic D-lactylation and implicate GLO2 as a promising target for combating clinical inflammatory disorders.
© 2024. The Author(s).

Studies suggest that the dynamic changes in cellular response might correlate with disease severity and outcomes in SARS-CoV-2 patients. The study aimed to investigate the dynamic changes of lymphocyte subsets in patients with COVID-19. In this regard, 53 patients with COVID-19 were prospectively included, classified as mild, moderate, and severe. The peripheral lymphocyte profiles (LyT, LyB, and NK cells), as well as CD4+/CD8+, CD3+/CD19+, CD3+/NK and CD19+/NK ratios, and their dynamic changes during hospitalization and correlation with disease severity and outcome were assessed. We found significant differences in CD3+ lymphocytes between severity groups (p < 0.0001), with significantly decreased CD3+CD4+ and CD3+CD8+ in patients with severe disease (p < 0.0001 and p = 0.048, respectively). Lower CD3+/CD19+ and CD3+/NK ratios among patients with severe disease (p = 0.019 and p = 0.010, respectively) were found. The dynamic changes of lymphocyte subsets showed a significant reduction in NK cells (%) and a significant increase in CD3+CD4+ and CD3+CD8+ cells in patients with moderate and severe disease. The ROC analysis on the relationship between CD3+ cells and fatal outcome yielded an AUC of 0.723 (95% CI 0.583-0.837; p = 0.007), while after addition of age and SpO2, ferritin and NLR, the AUC significantly improved to 0.927 (95%CI 0.811-0.983), p < 0.001 with a sensitivity of 90.9% (95% CI 58.7-99.8%) and specificity of 85.7% (95% CI 69.7-95.2%). The absolute number of CD3+ lymphocytes might independently predict fatal outcomes in COVID-19 patients and T-lymphocyte subset evaluation in high-risk patients might be useful in estimating disease progression.

Inborn errors of human IFN-γ-dependent macrophagic immunity underlie mycobacterial diseases, whereas inborn errors of IFN-α/β-dependent intrinsic immunity underlie viral diseases. Both types of IFNs induce the transcription factor IRF1. We describe unrelated children with inherited complete IRF1 deficiency and early-onset, multiple, life-threatening diseases caused by weakly virulent mycobacteria and related intramacrophagic pathogens. These children have no history of severe viral disease, despite exposure to many viruses, including SARS-CoV-2, which is life-threatening in individuals with impaired IFN-α/β immunity. In leukocytes or fibroblasts stimulated in vitro, IRF1-dependent responses to IFN-γ are, both quantitatively and qualitatively, much stronger than those to IFN-α/β. Moreover, IRF1-deficient mononuclear phagocytes do not control mycobacteria and related pathogens normally when stimulated with IFN-γ. By contrast, IFN-α/β-dependent intrinsic immunity to nine viruses, including SARS-CoV-2, is almost normal in IRF1-deficient fibroblasts. Human IRF1 is essential for IFN-γ-dependent macrophagic immunity to mycobacteria, but largely redundant for IFN-α/β-dependent antiviral immunity.Crown Copyright © 2022. Published by Elsevier Inc. All rights reserved.

Risk factors for the development of severe COVID-19 include several comorbidities, but age was the most striking one since elderly people were disproportionately affected by SARS-Cov-2. Major drivers that can explain this markedly unfavourable response in the elderly are inflammaging and immunosenescence. Recent reports have shown that the relationship between immunosenescence and COVID-19 can be bidirectional, since hospitalized patients with severe COVID-19 have an accumulation of senescent T cells suggesting that immunosenescence can be also exacerbated by SARS-CoV-2 infection. Therefore, the present work was designed to examine the emergence of immunosenescence in a longitudinal study in two distinct cohorts of COVID-19 patients, and to determine whether the senescence alterations were restricted to severe cases of the disease. Our data, with patients from Portugal and Brazil, identified their distinctive inflammatory profile and provided evidence of increased frequencies of senescent and exhausted T cells within a seven-day period in patients with mild to severe COVID-19. These results support the view that SARS-CoV2 infection can accelerate immunosenescence in both CD4 and CD8 T cell compartments in a short period of time.

Background: Adoptive T cell therapies including T cell receptor-engineered T (TCR-T) cell therapy are limited by poor in-vivo persistence. According to literature, aurora kinase inhibitors elicit glycolysis suppression and fatty acid oxidation enhancement. Less differentiated memory T cells rely more on fatty acid oxidation with better proliferative potency. Therefore, this study aims to determine whether aurora kinase inhibition during TCR-T cell preparation and expansion promote a more long-lived phenotype leading to T cells with increased in vivo persistence and efficacy. Methods The study involves preparing TCR-T cells with aurora kinase inhibitors for 7 days with anti-CD3/CD28 beads and IL-2. And the antitumor effects of these TCR-T cells were investigated in vitro and in subcutaneous and metastatic melanoma models. Results TCR-T cells cultured with aurora kinase A and B inhibitor generated more effector T cells (~ 79% and ~ 77%) when compared to cells with beads alone (~ 36%) after in-vitro re-stimulation. And aurora kinase B inhibitor-treatment benefits in vivo persistence of TCR-T cells and extends survival in both subcutaneous and metastatic melanoma model. Phenotypic analysis shows an increased percentage of T cells stem cell-like memory properties in terms of aurora kinase inhibition. The stemness of T cells is maintained by delaying proliferation mediated by limitation of mTOR activity. Conclusion Taken together, these data suggest that incorporation of aurora kinase inhibitor in TCR-T cells preparation might be a potential method to generate long-live TCR-T cells with potent therapeutic characteristics.