ATF4-SLC7A11-GSH axis mediates the acquisition of immunosuppressive properties by activated CD4+ T cells in low arginine condition.

The tumor microenvironment (TME) is restricted in metabolic nutrients including the semi-essential amino acid arginine. While complete arginine deprivation causes T cell dysfunction, it remains unclear how arginine levels fluctuate in the TME to shape T cell fates. Here, we find that the 20-µM low arginine condition, representing the levels found in the plasma of patients with cancers, confers Treg-like immunosuppressive capacities upon activated T cells. In vivo mouse tumor models and human single-cell RNA-sequencing datasets reveal positive correlations between low arginine condition and intratumoral Treg accumulation. Mechanistically, low arginine-activated T cells engage in metabolic and transcriptional reprogramming, using the ATF4-SLC7A11-GSH axis, to preserve their suppressive function. These findings improve our understanding of the role of arginine in human T cell biology with potential applications for immunotherapy strategies.

Trophoblast-Derived Extracellular Vesicles Promote Preeclampsia by Regulating Macrophage Polarization.

BACKGROUND: Systemic inflammation caused by dysfunctional macrophages is a crucial pathogenetic event in preeclampsia (PE). Trophoblast-derived extracellular vesicles (T-EVs) are potent immune cell signaling modulators in pregnancy. Herein, we aimed to investigate T-EVs' effect and mechanism on macrophage polarization and its role in PE pathogenesis, which remain unclear. METHODS: Flow cytometry and immunochemistry were used to determine placental macrophage phenotypes. T-EVs were immuno-isolated via placental alkaline phosphatase antibody and identified by transmission electron microscopy and nanoparticle tracking analysis. Quantitative real-time polymerase chain reaction and flow cytometry were used to examine the effects of T-EVs on macrophage polarization, and correlation analysis of T-EVs lipidomics and macrophages transcriptome were performed to explore how T-EVs modulate macrophages. Animal experiments were established to investigate the relationship among PE, T-EVs, and macrophages. RESULTS: Macrophages shift from the M2 to M1 phenotype in the preeclamptic placenta. Also, T-EVs from women with PE (PE-EVs) significantly upregulated M1 gene markers and significantly downregulated CD163 expression in macrophages compared with T-EVs in women with normal pregnancies (NP-EVs). Mechanistically, correlation analysis with T-EVs lipidome and the transcriptome of macrophages treated with PE-EVs or NP-EVs indicated that 37 lipids altered in PE-EVs considerably affected classical inflammatory biological pathways in macrophages. Finally, animal experiments revealed that PE-EVs triggered PE-like symptoms in pregnant mice, which were alleviated after macrophage depletion. CONCLUSIONS: T-EVs from women with PE could promote preeclampsia by inducing macrophage imbalance polarization, signifying a potential novel interventional target for the prevention and management of PE.

Extracellular Vesicle-Mediated Secretion of HLA-E by Trophoblasts Maintains Pregnancy by Regulating the Metabolism of Decidual NK Cells.

Extracellular vesicles derived from trophoblasts (T-EVs) play an important role in pregnancy, but the mechanism is not entirely clear. In this study, we found that HLA-E, which is mostly confined to the cytoplasm of trophoblast cells, was secreted by T-EVs. The level of HLA-E in T-EVs from unexplained recurrent spontaneous abortion (URSA) patients was lower than that in normal pregnancy (NP) and RSA patients who had an abnormal embryo karyotype (AK-RSA). T-EVs promoted secretion of IFN-γ and VEGFα by decidual NK (dNK) cells from URSA patients via HLA-E, VEGFα was necessary for angiogenesis and trophoblast growth, and IFN-γ inhibited Th17 induction. Glycolysis and oxidative phosphorylation (OxPhos) were involved in this process. Glycolysis but not OxPhos of dNK cells facilitated by T-EVs was dependent on mTORC1 activation. Inhibition of T-EV production in vivo increased the susceptibility of mice to embryo absorption, which was reversed by transferring exogenous T-EVs. T-EVs promoted secretion of IFN-γ and VEGFα by dNK cells to maintain pregnancy via Qa-1 in abortion-prone mouse models. This study reveals a new mechanism of pregnancy maintenance mediated by HLA-E via T-EVs.

TPX2 silencing mediated by joint action of microvesicles and ultrasonic radiation inhibits the migration and invasion of SKOV3 cells.

Ovarian cancer, with its high morbidity, has one of the highest mortality rates among gynecological malignant tumors. Overexpression of targeting protein for Xklp2 (TPX2) has been identified in numerous malignant tumors. The present study sought to determine whether TPX2 silencing inhibited the growth and metastasis of ovarian cancer cells, and whether microvesicles­ and ultrasonic radiation­mediated small interfering (si)RNA­TPX2 transfection may improve the therapeutic effect. The SKOV3 cell line, derived from papillary serous cytadenocarcinoma of the human ovary, was selected as a cell model. Cells were divided into five groups: Control, siRNA­TPX2, siRNA­TPX2 + microvesicle (M), siRNA­TPX2 + ultrasonic irradiation (UI), and siRNA­TPX2 + M + UI. Cell viability was evaluated under the aforementioned conditions via the Cell Counting kit 8 (CCK8) assay. Cell migration and invasion were detected using Transwell assays. The expression levels of associated genes, including epithelial cadherin (E­cadherin), metalloproteinase inhibitor 2 (TIMP­2), metastasis associated 1 (MTA1) and matrix metallopeptidase 2 (MMP2), were analyzed using reverse transcription­quantitative polymerase chain reaction analysis and western blotting. MMP2 activity was determined using a gelatin zymography assay. The results suggested that TPX2 serves an important role in the development of SKOV3 cells; it is additionally able to inhibit cell migration and invasion by upregulating E­cadherin and TIMP2, downregulating MMP2 and MTA1, and inhibiting the phosphorylation of p38 and c­Jun N­terminal kinase. The inhibitory effect of siRNA­TPX2 on SKOV3 cellular metastasis in the presence of microvesicles and ultrasonic radiation was observed to be improved compared with the control. It is proposed that the combination of microvesicles and ultrasonic radiation with TPX2 silencing has the potential to be an effective gene therapy against ovarian cancer.