Monocyte-Derived Dendritic Cells (MDDCs) from Spondyloarthritis (SpA) Patients Exhbit a Coordinated Downregulation of the Cholesterol (chol) Biosynthesis Pathway That Relates to Lipid Overload

Maxime Breban¹, Clémence Desjardin², Emmanuel Chaplais³, Alice Talpin³, Felicie Costantino⁴, Christophe Hue³, Aude Jobart-Malfait⁵, Benoit Maury⁶, Stanislas Grassin-Delyle³, Nelly Bonilla⁷, Ariane Leboime⁸, Roula Said Nahal⁹, Franck Letourneur⁷, Sébastien Jacques⁷, Anne Boland¹⁰, Jean-François Deleuze¹⁰, Gilles Chiocchia¹¹ and Henri-Jean Garchon^3,6,12, ¹Rheumatology, Ambroise Paré Hospital (AP-HP), Versailles Saint Quentin en Yvelines University, INSERM UMR1173, Boulogne-Billancourt, France, ²INSERM UMR1173, Montigny-le-Bretonneux, France, ³Inserm U1173, Montigny-le-Bretonneux, France, ⁴Hôpital Universitaire Ambroise Pare, Paris, France, ⁵INSERM-U1173, University of Versailles Saint-Quentin-en-Yvelines, France, Montigny-le-Bretonneux, France, ⁶University of Versailles Saint-Quentin, Simone Veil school of Health Sciences, Montigny-le-Bretonneux, France, ⁷Institut Cochin, Inserm U1016, Paris, France, ⁸Ambroise Paré Hospital Division of Rheumatology, Assistance Publique des Hopitaux de Paris, Boulogne-Billancourt, France, ⁹Ambroise Paré Hospital, Boulogne-Billancourt, France, ¹⁰Centre National de Recherche en Génomique Humaine, Evry, France, ¹¹Service d'Immunologie, Ambroise Paré Hospital, University of Versailles Saint-Quentin-en-Yvelines, Boulogne, France, Boulogne-Billancourt, France, ¹²Ambroise Paré Hospital Division of Genetics, AP-HP, Boulogne-Billancourt, France

Meeting: 2017 ACR/ARHP Annual Meeting

Date of first publication: September 18, 2017

Keywords: Cholesterol, Dendritic cells, human leukocyte antigens (HLA), spondylarthritis and transcriptional regulation

Session Information

Date: Monday, November 6, 2017

Title: Spondyloarthropathies and Psoriatic Arthritis – Pathogenesis, Etiology Poster II

Session Type: ACR Poster Session B

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

Background/Purpose:

Gene expression studies are useful to investigate the pathogenesis of complex diseases. The critical role of antigen-presenting cells such as dendritic cells (DCs) being suspected in SpA, we wished to study their particular biology, starting from unbiased transcriptomic experiment.

Methods:

MDDCs were obtained from circulating CD14+ monocytes after 7 days of culture with GMCSF + IL-4. Transcriptomes were profiled using Affymetrix microarrays (HuGene 1.0 ST) and further confirmed by RNA-seq (78 million paired-end reads (2×100 nt) per sample). Differentially expressed (DE) genes between SpA (ASAS criteria) and healthy controls (HC) were listed with LIMMA. Functional annotation was performed with DAVID and InnateDB. RT-qPCR was used to test the reproducibility of the signature over time. Intra-cellular lipid dropplets (LD) volume and number were quantified by Bodipy® labeling and confocal microscopy . Cellular content of chol pathway metabolites was quantified by mass spectrometry (MS).

Results:

For transcriptomic analysis, we generated 3 lists of DE genes (nominal p < 0.01) comparing (A) HLA-B27+ SpA (n=40) to B27-neg HC (n=30), (B) B27+ HC (n=44) to B27-neg HC and (C) B27+ SpA to B27+ HC. Subtraction A–B and intersection with C yielded a robust list of 68 genes affected by SpA controlling for unrelated HLA-B27 effect. Analysis of functional pathways revealed a significant overrepresentation of genes involved in chol biosynthesis and its regulation (p < 1×10^-4). Five of the 6 genes in this pathway (SQLE, MSMO1, LDLR, INSIG1, SREBF2) were downregulated in SpA. These findings were confirmed by RNA-seq on the same samples and by qPCR on a new series of samples drawn from the same group of individuals (11 SpA vs. 10 HC). Using MS, we evidenced a significant increase of chol and 27-OH-chol content in MDDC from another panel of SpA (n = 14) compared to HC (n = 8) (p < 0.05), suggesting that downregulation of cholesterol synthesis might be secondary to chol overload. Consistently, there was a highly significant increase in the size (p = 5×10^-4) and overall volume (p < 2×10^-4) of LD in SpA (n=12) compared to HC (n=11) MDDCs (Figure). Importantly, there was no difference of total nor fractionated chol plasma levels between SpA and controls.

Conclusion:

Our study identified a downregulation of the chol synthesis pathway in MDDCs from SpA patients that seems to be secondary to lipid overload in those cells. Our findings are consistent with a state of pre-activation of those cells that could lead to a strong inflammatory response to endogenous or environmental stimuli.

Figure:

Disclosure: M. Breban, None; C. Desjardin, None; E. Chaplais, None; A. Talpin, None; F. Costantino, None; C. Hue, None; A. Jobart-Malfait, None; B. Maury, None; S. Grassin-Delyle, None; N. Bonilla, None; A. Leboime, None; R. Said Nahal, None; F. Letourneur, None; S. Jacques, None; A. Boland, None; J. F. Deleuze, None; G. Chiocchia, None; H. J. Garchon, None.

To cite this abstract in AMA style:

Breban M, Desjardin C, Chaplais E, Talpin A, Costantino F, Hue C, Jobart-Malfait A, Maury B, Grassin-Delyle S, Bonilla N, Leboime A, Said Nahal R, Letourneur F, Jacques S, Boland A, Deleuze JF, Chiocchia G, Garchon HJ. Monocyte-Derived Dendritic Cells (MDDCs) from Spondyloarthritis (SpA) Patients Exhbit a Coordinated Downregulation of the Cholesterol (chol) Biosynthesis Pathway That Relates to Lipid Overload [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/monocyte-derived-dendritic-cells-mddcs-from-spondyloarthritis-spa-patients-exhbit-a-coordinated-downregulation-of-the-cholesterol-chol-biosynthesis-pathway-that-relates-to-lipid-overload/. Accessed .

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