Regulatory T (Treg) cells are considered as key regulators of adipose homeostasis and metabolic health. However, the underlying regulatory mechanisms remain unclear. Here we show that expression of G-protein-signaling modulator 1 (GPSM1) in CD4+ T cells in peripheral blood and visceral fat is significantly upregulated in humans upon obesity and glucose dysregulation. Genomic deletion of GPSM1 in CD4+ T cells or Treg cells in mice results in increased numbers of Treg cells in adipose tissues, restrained inflammation and improved insulin and glucose tolerance upon feeding with high fat diet. These metabolic changes are mediated by the maintenance of a specific CD73+CD103+ Treg cell subpopulation. By contrast, mice with CD4+ T-cell-specific overexpression of GPSM1 are characterized by decreased numbers of Treg cells and are more prone to adipose tissue dysfunction and metabolic deterioration. Mechanistically, a RHOA-cell stiffness-TAZ axis mediates the effects of GPSM1 on the abundance of Treg cells. Furthermore, adoptive transfer of GPSM1-deficent Treg cells promotes energy expenditure and improve glucose and lipid metabolism in Rag1 -/- mice. In summary, GSPM1 expression in Treg cells and especially in a subset specialized for metabolic regulation is an important regulator of the overall energy homeostasis.
© 2026. The Author(s).

Sensing of viral pathogens by RIG-I-like receptors (RLRs) requires their priming via dephosphorylation mediated by the protein phosphatase 1 regulatory subunit 12 C (R12C), which is activated upon virus-induced actin rearrangements. Here, we show that the HIV-1 accessory protein Nef prevents R12C-mediated RLR priming, thereby suppressing viral sensing. HIV-1 variants containing single point mutations in Nef (F/R191A) that ablate its ability to bind the actin-modulating kinase PAK2 trigger increased interferon (IFN) responses in primary CD4+ T cells, macrophages, and dendritic cells. Neutralization of IFN suppresses innate immune activation and enhances the replication of Nef-mutated HIV-1. We further demonstrate that HIV-1 encoding Nef F/R191A is sensed by MDA5 after proviral integration in an R12C-dependent manner. Mechanistically, PAK2 binding by Nef promotes actin repair and stabilization, thereby preventing re-localization of R12C to MDA5 and RIG-I and their subsequent dephosphorylation. Our data identify Nef as an antagonist of actin-R12C-mediated RLR priming, enabling HIV-1 to escape immune control.
© 2025. The Author(s).

More than 90% of advanced gastric cancers (GC) are microsatellite-stable (MSS). Compared to the high response rate of immune checkpoint inhibitors (ICI) in microsatellite-instability-high (MSI-H) GCs, only 10% of unstratified MSS GCs respond to ICIs. In this study, we apply semi-supervised learning to stratify potential ICI responders in MSS GCs, achieving high accuracy, quantified by an area under the curve of 0.924. Spatial analysis of the tumor microenvironment of ICI-sensitive GCs reveals a high level of T-bet+ CD8 + T cell infiltration in their tumor compartments. T-bet+ CD8 + T cells exhibit superior anti-tumor activity due to their increased ability to infiltrate tumors and secrete cytotoxic molecules. Adoptive transfer of T-bet+ CD8 + T cells boosts anti-tumor immunity and confers susceptibility to ICIs in immune-ignorant MSS GCs in a humanized mouse model. Spatial RNA sequencing suggests a positive-feedback loop between T-bet+ T cells and PD-L1+ tumor cells, which eventually drives T cell exhaustion and can therefore be leveraged for ICI therapy. In summary, our research provides insights into the underlying mechanism of anti-tumor immunity and deepens our understanding of varied ICI responses in MSS GCs.
© 2025. The Author(s).

Chimeric antigen receptor (CAR) T cell therapy represents a cutting-edge cancer treatment, making the development and testing of CAR T cells crucial for advancing this therapeutic strategy. We present a protocol for creating and characterizing human epidermal growth factor receptor 2 (HER2)- and glypican-3 (GPC3)-metabolic reprogramming (MR)-CAR T cells by overexpressing adenosine deaminase 1 (ADA1) and CD26 (also known as dipeptidylpeptidase-4 or DPP4). This approach effectively converts immunosuppressive adenosine into inosine, which supports T cell survival in glucose-deficient tumor microenvironments. The protocol includes producing retroviral vectors, generating CAR T cells, and conducting ecto-ADA1 activity, cytotoxicity, cell migration, and RNA sequencing assays. For complete details on the use and execution of this protocol, please refer to Hu et al.1.
Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.

Chimeric antigen receptor (CAR) T cell therapy is hindered in solid tumor treatment due to the immunosuppressive tumor microenvironment and suboptimal T cell persistence. Current strategies do not address nutrient competition in the microenvironment. Hence, we present a metabolic refueling approach using inosine as an alternative fuel. CAR T cells were engineered to express membrane-bound CD26 and cytoplasmic adenosine deaminase 1 (ADA1), converting adenosine to inosine. Autocrine secretion of ADA1 upon CD3/CD26 stimulation activates CAR T cells, improving migration and resistance to transforming growth factor β1 suppression. Fusion of ADA1 with anti-CD3 scFv further boosts inosine production and minimizes tumor cell feeding. In mouse models of hepatocellular carcinoma and non-small cell lung cancer, metabolically refueled CAR T cells exhibit superior tumor reduction compared to unmodified CAR T cells. Overall, our study highlights the potential of selective inosine refueling to enhance CAR T therapy efficacy against solid tumors.
Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.