RNA Sequencing Detection of Gene Dysregulation in Epithelial Cells Sorted from Salivary Gland Tissue Reveals Interesting Pathways Involved in Primary Sjögren’s Syndrome Pathophysiology

Elodie Rivière^1,2, Nicolas Tchitchek¹, Gaetane Nocturne^1,3, Juliette Pascaud¹, Alexandre Virone¹, Saida Boudaoud¹, Alice Thai⁴, Normand Allaire⁴, Bernd Jagla⁵, Michael Mingueneau⁴ and Xavier Mariette^1,3, ¹Immunology of viral Infections and Autoimmune Diseases, IDMIT, CEA - Université Paris Sud - INSERM U1184, Le Kremlin Bicêtre & Fontenay aux Roses, France, ²Arthritis Fondation Courtin, Paris, France, ³Rheumatology, Université Paris Sud, Le Kremlin Bicêtre, France, ⁴Immunology Research, Biogen, Cambridge, MA, ⁵Biomarker Discovery Platform UTechS CB, Hub de Bioinformatique et biostatistique C3IB, Institut Pasteur, Paris, France

Meeting: 2018 ACR/ARHP Annual Meeting

Keywords: Gene Expression, Sjogren's syndrome and salivary gland

Session Information

Date: Monday, October 22, 2018

Title: Sjögren's Syndrome – Basic and Clinical Science Poster

Session Type: ACR Poster Session B

Session Time: 9:00AM-11:00AM

Background/Purpose: Primary Sjögren’s syndrome (pSS) is a chronic autoimmune disorder characterized by lymphocytic infiltrates and destruction of the salivary glands. Several lines of evidence support the hypothesis that salivary gland epithelial cells (SGECs) are not only the target of autoimmunity in pSS patients but may also play a role for its initiation and maintenance.

The objective of this study was to establish a transcriptomic map of differentially expressed genes in SGEC from pSS patients compared to controls using RNASeq analysis.

Methods: Patients had pSS according to 2016 EULAR/ACR criteria and controls had sicca symptoms without any antibodies and with normal lip biopsy. SGEC, B, T CD4 and CD8 lymphocytes were sorted from salivary gland biopsies from 9 pSS patients and 4 controls, using a FACS ARIA. Total RNASeq profiling was performed using MiSeq (Illumina). For SGEC subset, 4 samples were excluded due to a contamination by B lymphocytes, thus analysis was performed on 5 pSS and 4 controls. We identified transcriptional differences between pSS and controls SGEC using R software. Functional enrichment analysis was performed with Ingenuity Pathway Analysis software.

Results: In SGEC, 495 genes were differentially expressed between pSS and controls. 280 genes were up-regulated, and 215 genes were down-regulated. Enrichment analysis (Table 1) highlighted IL-7 signaling pathways (including IL-7, STAT5A, STAT1 genes) and interferon signaling (including OAS1, IFIT3, IFI6, TAP1 genes). Other genes potentially involved in immune responses and interactions between SGEC and lymphocytes were significantly up-regulated, including bone marrow stromal cell antigen 2, HLA-DRA, BAFF-R and IL-23 A (Table2). These results need to be confirmed by RT qPCR. However, consistent results have already been obtained in our laboratory, showing that IL-7 serum level is increased in pSS patients compared to controls and that SGECs secrete IL-7 after interferon stimulation. The analysis of the other sorted cells subtypes is ongoing.

Conclusion: Immune interactions between SGEC and B or T lymphocytes could represent a key in the understanding of the initiation and/or maintenance of autoimmunity in pSS. Our study highlights the key role of epithelial cells in activation of immune cells. In vitro experiments are needed to confirm these results and elucidate the molecular mechanisms.

Table 1: Pathways identified as statistically over-represented with Ingenuity Pathways Analysis in epithelial cells from pSS compared to controls.

Pathway	-log p-value
Primary Immunodeficiency Signaling	4,08
Interferon Signaling	3,52
B Cell Development	2,89
Role of JAK2 in Hormone-like Cytokine Signaling	2,73
IL-7 Signaling Pathway	2,51

Table 2: Selection of genes differentially expressed between pSS and controls in SGEC

Gene Symbol	log2 fold-change	p-value
IL-7	2.56	0.002
BST2	4.08	0.0002
HLA-DRA	1.84	0.0372
IL-23 A	3.59	0.0155
BAFF-R	4.94	0.0097

Disclosure: E. Rivière, Arthritis Fondation PhD fellowship, 2; N. Tchitchek, None; G. Nocturne, None; J. Pascaud, None; A. Virone, None; S. Boudaoud, None; A. Thai, Biogen, 3; N. Allaire, Biogen Idec, 3; B. Jagla, None; M. Mingueneau, Biogen, 3; X. Mariette, None.

To cite this abstract in AMA style:

Rivière E, Tchitchek N, Nocturne G, Pascaud J, Virone A, Boudaoud S, Thai A, Allaire N, Jagla B, Mingueneau M, Mariette X. RNA Sequencing Detection of Gene Dysregulation in Epithelial Cells Sorted from Salivary Gland Tissue Reveals Interesting Pathways Involved in Primary Sjögren’s Syndrome Pathophysiology [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 9). https://acrabstracts.org/abstract/rna-sequencing-detection-of-gene-dysregulation-in-epithelial-cells-sorted-from-salivary-gland-tissue-reveals-interesting-pathways-involved-in-primary-sjogrens-syndrome-pathophysiology/. Accessed .

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