Alteration of innate lymphoid cell homeostasis mainly concerns salivary glands in primary Sjögren's syndrome.

OBJECTIVE: Innate lymphoid cells (ILCs) are a cell population implicated in the pathogenesis of various chronic inflammatory diseases, but little is known about their role in primary Sjögren's syndrome (pSS). The aim of this study was to assess the frequency of ILC subsets in peripheral blood (PB) and their quantity and location in minor salivary glands (MSGs) in pSS. METHODS: The frequency of ILC subsets was analysed in the PB of patients with pSS and healthy controls (HCs) by flow cytometry. The amount and location of ILC subsets in MSGs were studied in patients with pSS and sicca controls by immunofluorescence assay. RESULTS: In PB, the frequency of ILC subsets did not differ between patients with pSS and HCs. The circulating frequency of the ILC1 subset was increased in patients with pSS with positive anti-SSA antibodies and that of the ILC3 subset was reduced in patients with pSS with glandular swelling. In MSGs, the ILC3 number was higher in lymphocytic-infiltrated than non-infiltrated tissue in patients with pSS and normal glandular tissues in sicca controls. The ILC3 subset was preferentially located at the periphery of infiltrates and was more abundant in small infiltrates of recently diagnosed pSS. CONCLUSION: Altered ILC homeostasis mainly concerns salivary glands in pSS. Most ILCs in MSGs consist of the ILC3 subset, located at the periphery of lymphocytic infiltrates. The ILC3 subset is more abundant in smaller infiltrates and in recently diagnosed pSS. It might play a pathogenic role in the development of T and B lymphocyte infiltrates in the early stages of pSS.

Association Between Bruton's Tyrosine Kinase Gene Overexpression and Risk of Lymphoma in Primary Sjögren's Syndrome.

OBJECTIVE: We undertook this study to analyze whole blood gene expression and to investigate the role of B cell genes in primary Sjögren's syndrome-related non-Hodgkin lymphoma (primary SS-NHL). METHODS: Peripheral whole blood samples were collected from 345 well-phenotyped patients with primary SS enrolled in the prospective Assessment of Systemic Signs and Evolution in Sjögren's Syndrome (ASSESS) cohort. Transcriptomic analysis was performed using human Clariom S Arrays (Affymetrix). In our primary analysis, we considered patients with incident lymphoma (i-primary SS-NHL) as the case group and all patients without lymphoma as the comparison group. In our sensitivity analyses, we considered all patients with primary SS-NHL, including those with a history of lymphoma (h-primary SS-NHL), as the case group and primary SS patients without lymphoma, stratified on their risk factors of lymphoma, as the comparison group. RESULTS: Twenty-one patients with primary SS-NHL (including 8 with i-primary SS-NHL and 13 h-primary SS-NHL) were eligible for transcriptomic analysis; we compared these patients to 324 primary SS controls without lymphoma, including 110 with moderate to severe disease activity and 61 with no risk factor of lymphoma. Functional clustering analyses revealed an enrichment of genes related to innate and adaptive immunity, including B cell-related genes. Bruton's tyrosine kinase (BTK) and a proliferation-inducing ligand (APRIL) genes were overexpressed before the occurrence of lymphoma in patients with incident lymphoma compared with patients without lymphoma. In sensitivity analyses, BTK was consistently up-regulated across all comparisons performed. BTK expression was associated with risk of lymphoma on multivariate analyses, which considered 9 validated predictors of lymphoma in primary SS. CONCLUSION: BTK and APRIL were overexpressed in the peripheral blood of primary SS patients prior to lymphoma. The association between BTK, APRIL, and primary SS-NHL requires confirmation in other prospective cohorts.

Identification of new candidate drugs for primary Sjögren's syndrome using a drug repurposing transcriptomic approach.

OBJECTIVES: To date, no immunomodulatory drug has demonstrated its efficacy in primary SS (pSS). We sought to analyse potential commonalities between pSS transcriptomic signatures and signatures of various drugs or specific knock-in or knock-down genes. METHODS: Gene expression from peripheral blood samples of patients with pSS was compared with that of healthy controls in two cohorts and three public databases. In each of the five datasets, we analysed the 150 most up- and downregulated genes between pSS patients and controls with regard to the differentially expressed genes resulting from the biological action on nine cell lines of 2837 drugs, 2160 knock-in and 3799 knock-down genes in the Connectivity Map database. RESULTS: We analysed 1008 peripheral blood transcriptomes from five independent studies (868 patients with pSS and 140 healthy controls). Eleven drugs could represent potential candidate drugs, with histone deacetylases and PI3K inhibitors among the most significantly associated. Twelve knock-in genes were associated with a pSS-like profile and 23 knock-down genes were associated with a pSS-revert profile. Most of those genes (28/35, 80%) were interferon-regulated. CONCLUSION: This first drug repositioning transcriptomic approach in SS confirms the interest of targeting interferons and identifies histone deacetylases and PI3K inhibitors as potential therapeutic targets.

Temporal multiomic modeling reveals a B-cell receptor proliferative program in chronic lymphocytic leukemia.

B-cell receptor (BCR) signaling is crucial for the pathophysiology of most mature B-cell lymphomas/leukemias and has emerged as a therapeutic target whose effectiveness remains limited by the occurrence of mutations. Therefore, deciphering the cellular program activated downstream this pathway has become of paramount importance for the development of innovative therapies. Using an original ex vivo model of BCR-induced proliferation of chronic lymphocytic leukemia cells, we generated 108 temporal transcriptional and proteomic profiles from 1 h up to 4 days after BCR activation. This dataset revealed a structured temporal response composed of 13,065 transcripts and 4027 proteins, comprising a leukemic proliferative signature consisting of 430 genes and 374 proteins. Mathematical modeling of this complex cellular response further highlighted a transcriptional network driven by 14 early genes linked to proteins involved in cell proliferation. This group includes expected genes (EGR1/2, NF-kB) and genes involved in NF-kB signaling modulation (TANK, ROHF) and immune evasion (KMO, IL4I1) that have not yet been associated with leukemic cells proliferation. Our study unveils the BCR-activated proliferative genetic program in primary leukemic cells. This approach combining temporal measurements with modeling allows identifying new putative targets for innovative therapy of lymphoid malignancies and also cancers dependent on ligand-receptor interactions.

BCR-associated factors driving chronic lymphocytic leukemia cells proliferation ex vivo.

A chronic antigenic stimulation is believed to sustain the leukemogenic development of chronic lymphocytic leukemia (CLL) and most of lymphoproliferative malignancies developed from mature B cells. Reproducing a proliferative stimulation ex vivo is critical to decipher the mechanisms of leukemogenesis in these malignancies. However, functional studies of CLL cells remains limited since current ex vivo B cell receptor (BCR) stimulation protocols are not sufficient to induce the proliferation of these cells, pointing out the need of mandatory BCR co-factors in this process. Here, we investigated benefits of several BCR co-stimulatory molecules (IL-2, IL-4, IL-15, IL-21 and CD40 ligand) in multiple culture conditions. Our results demonstrated that BCR engagement (anti-IgM ligation) concomitant to CD40 ligand, IL-4 and IL-21 stimulation allowed CLL cells proliferation ex vivo. In addition, we established a proliferative advantage for ZAP70 positive CLL cells, associated to an increased phosphorylation of ZAP70/SYK and STAT6. Moreover, the use of a tri-dimensional matrix of methylcellulose and the addition of TLR9 agonists further increased this proliferative response. This ex vivo model of BCR stimulation with T-derived cytokines is a relevant and efficient model for functional studies of CLL as well as lymphoproliferative malignancies.

Reduced DICER1 Expression Bestows Rheumatoid Arthritis Synoviocytes Proinflammatory Properties and Resistance to Apoptotic Stimuli.

OBJECTIVE: While the regulatory role of individual microRNAs (miRNAs) in rheumatoid arthritis (RA) is well established, the role of DICER1 in the pathogenesis of the disease has not yet been investigated. The purpose of this study was to analyze the expression of factors involved in miRNA biogenesis in fibroblast-like synoviocytes (FLS) from RA patients and to monitor the arthritis triggered by K/BxN serum transfer in mice deficient in the Dicer gene (Dicer(d/d) ). METHODS: The expression of genes and precursor miRNAs was quantified by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). MicroRNA macroarray profiling was monitored by qRT-PCR. Cytokines were quantified by enzyme-linked immunosorbent assay. Experimental arthritis in mice was achieved by the transfer of serum from K/BxN donors. Apoptosis was quantified using an enzyme-linked immunosorbent assay. RESULTS: We found decreased DICER1 and mature miRNA expression in synovial fibroblasts from RA patients. These cells were hyperresponsive to lipopolysaccharide, as evidenced by their increased interleukin-6 secretion upon stimulation. Experimental serum-transfer arthritis in Dicer(d/d) mice confirmed that an unbalanced biogenesis of miRNAs correlated with an enhanced inflammatory response. Synoviocytes from both RA patients and Dicer(d/d) mice exhibited increased resistance to apoptotic stimuli. CONCLUSION: The findings of this study further substantiate the important role of DICER1 in the maintenance of homeostasis and the regulation of inflammatory responses.