Biology subjects

Gourhand, V.

Publications and source records attributed to Gourhand, V..

3 recordsLinked to original sources

bioRxiv2025

Targeting CXCR4-expressing TAMs in muscle-invasive bladder cancer to enhance tumor control after immunotherapy

Bladder cancer (BC) is a prevalent malignancy with poor prognosis in advanced stages. While immune checkpoint blockade has revolutionized immunotherapy, its efficacy remains limited for most advanced BC patients. The detailed characterization of BCs tumor microenvironment (TME) is a prerequisite to understand these mechanisms of resistance and to develop new therapeutic strategies. In this study, we used a genetically engineered BC mouse model resistant to anti-PD1 treatment, and BC patient samples, to investigate the evolution of tumor-associated macrophages (TAMs) during BC progression. We identified a subset of pro-tumor TAMs expressing CXCR4, predominantly found in advanced stages of BC-bearing mice and in half of muscle-invasive BC patients from the studied cohort. Interestingly, CXCR4+ TAM-rich regions were associated with CD8 T cell-excluded areas in both mice and patients. Administration of a small molecule CXCR4 inhibitor significantly reduced the number of pro-tumor TAMs within the tumor and markedly prolonged mouse survival. Incorporating this inhibitor into a tri-immunotherapy regimen further enhanced survival, highlighting the potential of targeting multiple pathways to strongly enhance anti-tumor effects and offering new hope for improving immunotherapy in advanced BC.

immunology↗

bioRxiv2024

Plasma cell heterogeneity is driven by type of immune challenge

Plasma cells play an essential role in humoral immunity, but many questions remain regarding the heterogeneity of this population, both in terms of ontogeny and involvement in the immune response. In this work, we have identified 5 subsets of plasma cells in human and mouse lymphoid tissues. These subpopulations were distinguished by differential expression of CD62L, CXCR4, Fc{gamma}RIIb and CD93. The antigenic context as well as the B cell of origin directed plasma cell differentiation towards specific subtypes that display distinct migratory and survival abilities in vivo. Altogether, ours results unveil that plasma cell phenotypic and functional heterogeneity relies on intrinsic imprinting during B cell activation.

immunology↗

bioRxiv2023

CXCR4 signaling strength regulates hematopoietic multipotent progenitor fate through extrinsic and intrinsic mechanisms

How cell-extrinsic niche-related and cell-intrinsic cues drive lineage specification of hematopoietic multipotent progenitors (MPPs) in the bone marrow (BM) is partly understood. We show that CXCR4 signaling strength regulates localization and fate of MPPs. In mice phenocopying the BM myeloid skewing of patients with WHIM Syndrome (WS), a rare immunodeficiency caused by gain-of-function CXCR4 mutations, enhanced mTOR signaling and overactive Oxphos metabolism were associated with myeloid rewiring of lymphoid-primed MPPs (or MPP4). Fate decision of MPP4 was also affected by molecular changes established at the MPP1 level. Mutant MPP4 displayed altered BM localization relative to peri-arteriolar structures, suggesting that extrinsic cues contribute to their myeloid skewing. Chronic treatment with CXCR4 antagonist AMD3100 or mTOR inhibitor Rapamycin rescued lymphoid capacities of mutant MPP4, demonstrating a pivotal role for the CXCR4-mTOR axis in regulating MPP4 fate. Our study thus provides mechanistic insights into how CXCR4 signaling regulates the lymphoid potential of MPPs.

cell biology↗