Changing phases of thermoelectrochemical cells
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Solar-driven interfacial evaporation technologies for food, energy and water
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Frequency of change determines effectiveness of microbial response strategies
Nature challenges microbes with change at different frequencies and demands an effective response for survival. Here, we used controlled laboratory experiments to investigate the effectiveness of different response strategies, such as post-translational modification, transcriptional regulation, and specialized versus adaptable metabolisms. For this, we inoculated replicated chemostats with an enrichment culture obtained from sulfidic stream microbiomes 16 weeks prior. The chemostats were submitted to alternatingly oxic and anoxic conditions at three frequencies, with periods of 1, 4 and 16 days. The microbial response was recorded with 16S rRNA gene amplicon sequencing, shotgun metagenomics, transcriptomics and proteomics. Metagenomics resolved provisional genomes of all abundant bacterial populations, mainly affiliated with Proteobacteria and Bacteroidetes. Almost all these populations maintained a steady growth rate under both redox conditions at all three frequencies of change. Our results supported three conclusions: (1) Oscillating oxic/anoxic conditions selected for generalistic species, rather than species specializing in only a single condition. (2) A high frequency of change selected for strong codon usage bias. (3) Alignment of transcriptomes and proteomes required multiple generations and was dependent on a low frequency of change.
Terminal differentiation and persistence of effector regulatory T cells essential for preventing intestinal inflammation
Regulatory T (Treg) cells are a specialized CD4+ T cell lineage with essential anti-inflammatory functions. Analysis of Treg cell adaptations to non-lymphoid tissues that enable their specialized immunosuppressive and tissue-supportive functions raises questions about the underlying mechanisms of these adaptations and whether they represent stable differentiation or reversible activation states. Here, we characterize distinct colonic effector Treg cell transcriptional programs. Attenuated T cell receptor (TCR) signaling and acquisition of substantial TCR-independent functionality seems to facilitate the terminal differentiation of a population of colonic effector Treg cells that are distinguished by stable expression of the immunomodulatory cytokine IL-10. Functional studies show that this subset of effector Treg cells, but not their expression of IL-10, is indispensable for colonic health. These findings identify core features of the terminal differentiation of effector Treg cells in non-lymphoid tissues and their function.
Cell-associated galectin 9 interacts with cytotoxic T cells confers resistance to tumor killing in nasopharyngeal carcinoma through autophagy activation
Immune effector cells, including cytotoxic T lymphocytes (CTLs) play essential roles in eliminating cancer cells. However, their functionality is often compromised, even when they infiltrate the tumor microenvironment (TME) or are transferred to cancer patients adoptively. In this study, we focused on galectin 9 (G9), an inhibitory ligand that we observed to be predominately positioned on the plasma membrane and readily interacts with CD8 + CTL in the TME of nasopharyngeal carcinoma (NPC). We discovered that cell-cell contact between activated effector CTLs and target tumor cells (TarTC) with G9 overexpression led to cellular death defects. Despite the formation of CTL–TarTC conjugates, there is no impact on the cell number nor viability of CTL, and the release of cytolytic content and associated activity were not completely abrogated. Instead, this interaction promoted autophagy and restricted necrosis in the TarTC. Furthermore, reducing G9 expression in tumor cells enhanced the suppressive effect on tumor growth upon adoptive transfer of activated effector CTL. Additionally, inhibiting autophagy effectively controlled tumor growth in cases of G9 overexpression. Therefore, we highlight the contribution of G9 in facilitating the resistance of NPC to CTL-mediated killing by inducing a selection-cell death state in tumor cells, characterized by increased autophagy and decreased necrosis.
γδ T-cell autoresponses to ectopic membrane proteins: a new type of pattern recognition
T-cell receptor (TCR) γδ-expressing cells are conserved lymphocytes of innate immunity involved in first-line defense and immune surveillance. TCRγδ recognizes protein/nonprotein ligands without the help of the major histocompatibility complex (MHC), especially via direct binding to protein ligands, which is dependent primarily on the δ chain complementary determining region 3 (CDR3δ). However, the mechanism of protein‒antigen recognition by human γδ TCRs remains poorly defined. We hypothesize that γδ TCRs recognize self-proteins expressed ectopically on the cell membrane that are derived from intracellular components under stress. Here, we mapped 16 intercellular self-proteins among 21,000 proteins with a huProteinChip as putative ligands for Vδ1/Vδ2 TCRs, 13 for Vδ1 TCRs and 3 for Vδ2 TCRs. Functional tests confirmed that ectopic nucleolin (NCL) is a ligand for the Vδ1 TCR, whereas protein-glutamine γ-glutamyltransferase K (TGM1) is a ligand for the Vδ2 TCR. In the context of radiation exposure, the ectopic expression of intracellular proteins on the tumor cell surface is related to the increased antitumor cytotoxicity of γδ T cells both in vitro and in vivo. In conclusion, the recognition of intracellular proteins that are ectopically expressed on somatic cells by human γδ TCRs is a basic interaction mechanism that enables new types of immune pattern recognition and a novel γδ TCR-ligand-based strategy for tumor immunotherapy.
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