Complex regulation of T cell functions during pregnancy is required to ensure materno-fetal tolerance. Here we reveal a novel pathway for the temporary suppression of maternal T cell responses in uncomplicated human pregnancies. Our results show that arginase activity is significantly increased in the peripheral blood of pregnant women and remarkably high arginase activities are expressed in term placentae. High enzymatic activity results in high turnover of its substrate L-arginine and concomitant reduction of this amino acid in the microenvironment. Amino acid deprivation is emerging as a regulatory pathway of lymphocyte responses and we assessed the consequences of this enhanced arginase activity on T cell responses. Arginase-mediated L-arginine depletion induces down-regulation of CD3 zeta, the main signalling chain of the TCR, and functional T cell hyporesponsiveness. Importantly, this arginase-mediated T cell suppression was reversible, as inhibition of arginase activity or addition of exogenous L-arginine restored CD3 zeta chain expression and T cell proliferation. Thus, L-arginine metabolism constitutes a novel physiological mechanism contributing to the temporary suppression of the maternal immune response during human pregnancy.
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http://dx.doi.org/10.1002/eji.200636542 | DOI Listing |
Nitric Oxide
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Division of Systems Biomedicine and Pharmacology, LACDR, Leiden University, the Netherlands.
COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), primarily manifests as a flu-like illness with lung injury, often necessitating supplemental oxygen. Elderly individuals and those with pre-existing cardiovascular diseases are at increased risk of mortality. The endothelial barrier disruption observed in patients indicates systemic viral invasion and widespread endotheliitis.
View Article and Find Full Text PDFPlacenta
January 2025
Department of Obstetrics and Gynecology, Affiliated Xiaoshan Hospital, Hangzhou Normal University, Hangzhou, Zhejiang, 311200, China. Electronic address:
Introduction: Pre-eclampsia (PE) is a pregnancy complication featuring hypertension and proteinuria. Metformin exerts clinically preventive effects on PE with an unspecified mechanism.
Methods: Placental tissues from PE patients and normal pregnant (NP) women were collected.
JCI Insight
January 2025
Department of Radiology, and.
Lung cancer is the leading cause of cancer deaths in the United States. New targeted therapies against the once-deemed undruggable oncogenic KRAS are changing current therapeutic paradigms. However, resistance to targeted KRAS inhibitors almost inevitably occurs; resistance can be driven by tumor cell-intrinsic changes or by changes in the microenvironment.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Spinal Surgery, The Third Affiliated Hospital of Soochow University, Changzhou, China.
Inflammation aggravates secondary damage following spinal cord injury (SCI). M1 microglia induce inflammation and exert neurotoxic effects, whereas M2 microglia exert anti-inflammatory and neuroprotective effects. The sine oculis homeobox (SIX) gene family consists of six members, including sine oculis homeobox homolog 1 (SIX1)-SIX6.
View Article and Find Full Text PDFGlioblastoma tumors remain a formidable challenge for immune-based treatments because of their molecular heterogeneity, poor immunogenicity, and growth in the largely isolated and immunosuppressive neural environment. As the tumor grows, GBM cells change the composition and architecture of the neural extracellular matrix (ECM), affecting the mobility, survival, and function of immune cells such as tumor-associated microglia and infiltrated macrophages (TAMs). We have previously described the unique expression of the ECM protein EFEMP1/fibulin-3 in GBM compared to normal brain and demonstrated that this secreted protein promotes the growth of the GBM stem cell (GSC) population.
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