Project description:Obesity is characterized by accumulation of T cells in insulin-sensitive tissues, including the visceral adipose tissue (VAT), that can interfere with the insulin signaling pathway eventually leading to insulin resistance (IR) and type 2 diabetes. Here, we found that PD-1+CD4 conventional T (Tconv) cells, endowed with a transcriptomic and functional profile of partially dysfunctional cells, are diminished in VAT of obese patients with dysglycemia (OB-Dys). These cells showed enhanced capacity to recirculate into the bloodstream and had a non-restricted TCRβ repertoire divergent from that of normoglycemic obese and lean individuals. PD-1+CD4 Tconv were reduced in the circulation of OB-Dys, exhibited an altered migration potential, and were detected in the liver of patients with non-alcoholic steatohepatitis. The findings suggest that dysglycemia in individuals with obesity is associated with recirculation of a heterogeneous population of partially dysfunctional PD-1+CD4 Tconv cells. These changes may contribute to the inter-organ crosstalk underlying IR
Project description:<p>PD-1 is an important immune checkpoint inhibitor that shows great promise in the clinic, particularly for melanoma and lung cancers. Since PD-1 is also expressed on infiltrating CD4+ Treg and Teffector cells in glioblastoma, we sought to better understand the role of PD-1 on these infiltrating CD4+ Treg and Teffector cells. To this end, we performed functional and transcriptional profiling using CD4+ Treg and Teffector cells isolated from healthy donors and glioblastoma patients (from both tumors and blood).</p>
Project description:Glioblastoma is the most common primary malignant brain tumor in adults and associated with poor survival. Standard-of-care chemotherapy and radiation confer a median overall survival of under two years. The Ivy Foundation Early Phase Clinical Trials Consortium conducted a randomized, multi institution clinical trial to evaluate immune responses and survival following neoadjuvant and/or adjuvant therapy with pembrolizumab, a programmed cell death protein 1 (PD-1) monoclonal antibody, in 35 patients with recurrent, surgically resectable glioblastoma. Patients who were randomized to receive neoadjuvant pembrolizumab, with continued adjuvant therapy following surgery, had significantly extended overall survival compared to patients that were randomized to receive adjuvant, post-surgical PD-1 blockade alone (hazard ratio = 0.39; P = 0.04, log-rank test). Neoadjuvant PD-1 blockade was associated with upregulation of T cell and interferon-γ-related genes, but downregulation of cell cycle related genes within the tumor, which was not seen in patients that received adjuvant therapy alone. Focal induction of programmed death-ligand 1 (PD-L1) in the tumor microenvironment was observed more frequently in the neoadjuvant group than in tumors obtained from patients treated only in the adjuvant setting. Similarly, neoadjuvant pembrolizumab was associated with clonal T cell expansion and the overlap of T cell receptors between tumor and blood, decreased PD-1 expression in T cells and a decreasing peripheral monocytic population. These findings suggest that the neoadjuvant administration of PD-1 blockade enhances the local and systemic anti-tumor immune response and may represent a more efficacious approach to the treatment of this uniformly lethal brain tumor. This trial was registered with ClinicalTrials.gov under the identifier NCT02852655 (https://clinicaltrials.gov/ct2/show/NCT02852655).
Project description:Glioblastoma is the most aggressive primary brain tumor in adults, with limited therapeutic success and, therefore, poor prognosis. Its malignancy is partly driven by the high proliferative capacity of glioblastoma cells, yet the underlying molecular mechanisms remain unclear. Recent studies have revealed transcriptomic similarities between glioblastoma cells and human fetal neural stem/progenitor cells (NSCs), suggesting that glioblastoma may exploit developmental programs that promote NSC proliferation. Fetal human NSCs rely on glutaminolysis—a metabolic pathway induced by the human-specific mitochondrial protein ARHGAP11B—to sustain proliferation. Here, we show that ARHGAP11B expression correlates with glioma malignancy and is essential for glioblastoma cell proliferation, implicating a critical role of glutaminolysis in tumor growth. Among glutaminolysis-related enzymes, glutamic-oxaloacetic transaminase 2 (GOT2) shows a strong positive correlation with glioma grade and poor patient prognosis. Functional assays reveal that GOT2 knockdown significantly suppresses glioblastoma cell growth, indicating that GOT2-mediated glutaminolysis is critical for their proliferation. Metabolomic profiling further shows that GOT2 is required for nucleotide precursor synthesis, underscoring its role in supporting DNA replication. Consistently, GOT2 depletion reduces the proportion of glioblastoma cells in the S phase of the cell cycle. These findings suggest glioblastoma cells hijack an evolutionarily adapted metabolic program to support malignant growth.