Pulmonary and systemic effects of inhaled crystalline silica in the HOCl-induced mouse model of systemic sclerosis: An experimental model of Erasmus syndrome.

Occupational exposure to crystalline silica is etiologically linked to an increased incidence of systemic sclerosis (SSc), also called Erasmus syndrome. The underlying mechanisms of silica-related SSc are still poorly understood. We demonstrated that early and repeated silica exposure contribute to the severity of SSc symptoms in the hypochloric acid (HOCl)-induced SSc mouse model.

Imaging Mass Cytometry to Decipher the Maturation of Tertiary Lymphoid Structures.

In the realm of inflammation, including conditions like cancers, infections, and autoimmune diseases, the emergence of tertiary lymphoid structures (TLS) holds significant implications for prognosis and treatment response. Yet, traditional methodologies such as immunohistochemistry and immunofluorescence falter in capturing the nuanced complexities of TLS, necessitating innovative approaches, like imaging mass cytometry (IMC), to unravel their significance. With the capacity to concurrently assess nearly 40 markers within the same tissue section, IMC transcends the constraints of traditional approaches.

Phenotypic, transcriptomic, and spatial characterization of CD45RB naïve mature B cells: Implications in Sjögren's disease.

The conventional classification of mature B cells overlooks the diversity within IgD CD27 naïve B cells. Here, to identify distinct mature naïve B cells, we categorized CD45RB B cells (NA RB-) and CD45RB B cells (NA RB+) and explore their function and localization in circulation and tissues under physiological and pathological conditions. NA RB+ B cells, found in secondary lymphoid organs, differentiate into plasmablasts and secrete IgM.

CD8 tissue-resident memory T cells are expanded in primary Sjögren's disease and can be therapeutically targeted by CD103 blockade.

Objective: Tissue-resident memory cells (Trm) are a subset of T cells residing persistently and long-term within specific tissues that contribute to persistent inflammation and tissue damage. We characterised the phenotype and function of Trm and the role of CD103 in primary Sjogren's syndrome (pSS).

Methods: In both pSS and non-pSS sicca syndrome patients, we examined Trm frequency, cytokine production in salivary glands (SG) and peripheral blood (PB).

Coupling imaging mass cytometry with Alcian blue histochemical staining for a single-slide approach.

Imaging mass cytometry (IMC) is a metal mass spectrometry-based method allowing highly multiplex immunophenotyping of cells within tissue samples. However, some limitations of IMC are its 1-µm resolution and its time and costs of analysis limiting respectively the detailed histopathological analysis of IMC-produced images and its application to small selected tissue regions of interest (ROI) of one to few square millimeters. Coupling on a single-tissue section, IMC and histopathological analyses could permit a better selection of the ROI for IMC analysis as well as co-analysis of immunophenotyping and histopathological data until the single-cell level.

High-content multimodal analysis supports the IL-7/IL-7 receptor axis as a relevant therapeutic target in primary Sjögren's syndrome.

Objective: While the involvement of IL-7/IL-7R axis in pSS has been described in relation to T cells, little is known about the contribution of this pathway in relationship with other immune cells, and its implication in autoimmunity. Using high-content multiomics data, we aimed at characterizing IL-7R expressing cells and the involvement of IL-7/IL-7R pathway in pSS pathophysiology.

Methods: An IL-7 signature established using RNA-sequencing of human PBMCs incubated with IL-7 was applied to 304 pSS patients, and on RNA-Seq datasets from tissue biopsies.

YOUPI: Your powerful and intelligent tool for segmenting cells from imaging mass cytometry data.

The recent emergence of imaging mass cytometry technology has led to the generation of an increasing amount of high-dimensional data and, with it, the need for suitable performant bioinformatics tools dedicated to specific multiparametric studies. The first and most important step in treating the acquired images is the ability to perform highly efficient cell segmentation for subsequent analyses. In this context, we developed YOUPI (Your Powerful and Intelligent tool) software.

Memory CD4+ T-Cell Lymphocytic Angiopathy in Fatal Forms of COVID-19 Pulmonary Infection.

The immunopathological pulmonary mechanisms leading to Coronavirus Disease (COVID-19)-related death in adults remain poorly understood. Bronchoalveolar lavage (BAL) and peripheral blood sampling were performed in 74 steroid and non-steroid-treated intensive care unit (ICU) patients (23-75 years; 44 survivors). Peripheral effector SARS-CoV-2-specific T cells were detected in 34/58 cases, mainly directed against the S1 portion of the spike protein.

Application of High-Throughput Imaging Mass Cytometry Hyperion in Cancer Research.

Imaging mass cytometry (IMC) enables the analysis of in-depth-phenotyped cells in their native microenvironment within the preserved architecture of a single tissue section. To date, it permits the simultaneous analysis of up to 50 different protein- markers targeted by metal-conjugated antibodies. The application of IMC in the field of cancer research may notably help 1) to define biomarkers of prognostic and theragnostic significance for current and future treatments against well-established and novel therapeutic targets and 2) to improve our understanding of cancer progression and its resistance mechanisms to immune system and how to overcome them.

High Dimensional Imaging Mass Cytometry Panel to Visualize the Tumor Immune Microenvironment Contexture.

The integrative analysis of tumor immune microenvironment (TiME) components, their interactions and their microanatomical distribution is mandatory to better understand tumor progression. Imaging Mass Cytometry (IMC) is a high dimensional tissue imaging system which allows the comprehensive and multiparametric exploration of tumor microenvironments at a single cell level. We describe here the design of a 39-antibody IMC panel for the staining of formalin-fixed paraffin-embedded human tumor sections.

STIM1 at the plasma membrane as a new target in progressive chronic lymphocytic leukemia.

Background: Dysregulation in calcium (Ca) signaling is a hallmark of chronic lymphocytic leukemia (CLL). While the role of the B cell receptor (BCR) Ca pathway has been associated with disease progression, the importance of the newly described constitutive Ca entry (CE) pathway is less clear. In addition, we hypothesized that these differences reflect modifications of the CE pathway and Ca actors such as Orai1, transient receptor potential canonical (TRPC) 1, and stromal interaction molecule 1 (STIM1), the latter being the focus of this study.

OMIP-048 MC: Quantification of calcium sensors and channels expression in lymphocyte subsets by mass cytometry.

Calcium (Ca ) signaling controls T-cell activation and functions. Ca concentrations are locally detected and controlled by Ca -sensors (STIM1 and 2 detecting the depletion from ER stores channels) and Ca -channels (ORAI1-3 in the cell membrane and VDAC1 in the outer mitochondrial membrane). We first validated and titrated antibodies to assess the expression of these Ca -sensors and -channels in human and murine cells, and further devised a 18-antibodies mass cytometry panel to characterize their expression in primary murine lymphocyte subsets.

Dysregulated Lymphoid Cell Populations in Mouse Models of Systemic Lupus Erythematosus.

Biases in the distribution and phenotype of T, B, and antigen-presenting cell populations are strongly connected to mechanisms of disease development in mouse models of systemic lupus erythematosus (SLE). Here, we describe longitudinal changes in lymphoid and antigen-presenting cell subsets in bone marrow, blood and spleen from two lupus-prone strains (MRL/lpr and B6.Sle1.

Calcium Signaling: From Normal B Cell Development to Tolerance Breakdown and Autoimmunity.

Maintenance of self-tolerance of auto-reactive lymphocytes is a fundamental mechanism to prevent the onset of autoimmune diseases. Deciphering the mechanisms involved in the deregulations leading to tolerance disruption and autoimmunity is still a major area of interest to identify new therapeutic targets and options. Ca signaling plays a major role in B cell normal development and is therefore finely tuned by B cell receptor (BCR)-dependent and independent pathways.

Efficient Plasma Cell Differentiation and Trafficking Require Cxcr4 Desensitization.

CXCR4 plays a central role in B cell immune response, notably by promoting plasma cell (PC) migration and maintenance in the bone marrow (BM). Gain-of-function mutations in CXCR4 affecting receptor desensitization have been reported in the rare immunodeficiency called WHIM syndrome (WS). Despite lymphopenia, patients mount an immune response but fail to maintain it over time.

Neutropenic Mice Provide Insight into the Role of Skin-Infiltrating Neutrophils in the Host Protective Immunity against Filarial Infective Larvae.

Our knowledge and control of the pathogenesis induced by the filariae remain limited due to experimental obstacles presented by parasitic nematode biology and the lack of selective prophylactic or curative drugs. Here we thought to investigate the role of neutrophils in the host innate immune response to the infection caused by the Litomosoides sigmodontis murine model of human filariasis using mice harboring a gain-of-function mutation of the chemokine receptor CXCR4 and characterized by a profound blood neutropenia (Cxcr4(+/1013)). We provided manifold evidence emphasizing the major role of neutrophils in the control of the early stages of infection occurring in the skin.

Symptomatic Improvement in Human Papillomavirus-Induced Epithelial Neoplasia by Specific Targeting of the CXCR4 Chemokine Receptor.

Human papillomavirus (HPV) infection is estimated to be the causal agent in 5% of all human cancers and is the leading cause of genital warts, which is the most common sexually transmitted viral disease. Currently, there are no medications to treat HPV infection, and therapeutic strategies primarily target HPV-related cancer rather than viral infection. HPV infection has severe effects on patients who display selective susceptibility to the virus in the context of primary immunodeficiencies, such as the warts, hypogammaglobulinemia, infections, and myelokathexis syndrome, which is caused by dysfunctions of CXCR4, the receptor for the CXCL12 chemokine.

Calcium signaling and cell fate: how can Ca2+ signals contribute to wrong decisions for Chronic Lymphocytic Leukemic B lymphocyte outcome?

Ca(2+) signaling is a key regulator of B lymphocyte cell fate and defects in this signaling pathway have been reported in numerous diseases such as Chronic lymphocytic leukemia (CLL). CLL is a B cell clonal disorder characterized by the accumulation of mature monoclonal CD5(+) B cells. Although CLL could be considered to be a proliferative disease, most circulating CLL B cells are arrested in the G0 phase of the cell cycle and present both defects in calcium (Ca(2+)) homeostasis and signaling.

Decreased expression of the glucocorticoid receptor-GILZ pathway in Kupffer cells promotes liver inflammation in obese mice.

Background & Aims: Kupffer cells (KC) play a key role in the onset of inflammation in non-alcoholic steatohepatitis (NASH). The glucocorticoid receptor (GR) induces glucocorticoid-induced leucine zipper (GILZ) expression in monocytes/macrophages and is involved in several inflammatory processes. We hypothesized that the GR-GILZ axis in KC may contribute to the pathophysiology of obesity-induced liver inflammation.

Inhibition of CD39 enzymatic function at the surface of tumor cells alleviates their immunosuppressive activity.

The ectonucleotidases CD39 and CD73 hydrolyze extracellular adenosine triphosphate (ATP) and adenosine diphosphate (ADP) to generate adenosine, which binds to adenosine receptors and inhibits T-cell and natural killer (NK)-cell responses, thereby suppressing the immune system. The generation of adenosine via the CD39/CD73 pathway is recognized as a major mechanism of regulatory T cell (Treg) immunosuppressive function. The number of CD39⁺ Tregs is increased in some human cancers, and the importance of CD39⁺ Tregs in promoting tumor growth and metastasis has been demonstrated using several in vivo models.

CXCR4 dysfunction in non-alcoholic steatohepatitis in mice and patients.

Homing of inflammatory cells to the liver is key in the progression of non-alcoholic steatohepatitis (NASH). An abnormal response of CD4+ T-cells from obese mice to the chemotactic effect of CXCL12 has been reported but the mechanism involved in this process and relevance in patients are unknown. We aimed to explore the mechanism involved in the abnormal chemotaxis of CXC chemokine ligand 12 (CXCL12) in several mouse models of NASH and the relevance in the context of human non-alcoholic fatty liver disease (NAFLD).