028 – Transcriptional analysis of peripheral monocytes upon fingolimod treatment in Relapsing Remitting Multiple Sclerosis patients
Giacomo Sferruzza (1) – Ferdinando Clarelli (2) – Laura Ferr (2) – Elisabetta Mascia (2) – Linda Ottoboni (3) – Melissa Sorosina (2) – Silvia Santoro (2) – Lucia Moiola (1) – Vittorio Martinelli (1) – Giancarlo Comi (1) – Filippo Martinelli Boneschi (4) – Paolo Provero (5) – Massimo Filippi (1) – Federica Esposito (2)
San Raffaele Scientific Institute, Neurology, Milano, Italy (1) – San Raffaele Scientific Institute, Laboratory of Human Genetics of Neurological Disorders, Milano, Italy (2) – San Raffaele Scientific Institute, Neuroimmunology Unit, Milano, Italy (3) – University of Milan, Departemente of Biomedical Sciences for Health, Milano, Italy (4) – University of Turin, Molecular Biotechnology and Heath Sciences, Torino, Italy (5)
Introduction: fingolimod (FTY) is a second-line drug approved for Relapsing Remitting Multiple Sclerosis (RRMS). FTY prevents lymphocyte migration outside lymph nodes, reducing peripheral lymphocytes counts, but several pieces of evidences suggest that it also inhibits myeloid cells activation. We investigated transcriptional changes induced by the drug in monocytes in order to better elucidate its mechanisms of action at the molecular and pathway levels.
Materials and Methods: 24 RRMS patients were sampled at baseline and after 6 months of FTY treatment. CD14+ monocytes were sorted with MACS MicroBeads system and RNA sequencing performed using Illumina NextSeq500 platform. Differentially expressed genes (DEGs) were identified and genes modulated by FTY (fold change [FC]>2 or FC<0.5 and false discovery rate [FDR]<5%) were considered for a pathway analysis based on KEGG database.
Subpaths activation state was also tested using MinePath tool.
Results: a marked down-regulation was observed in monocytes (208 down-regulated vs 0 up-regulated genes). Most of the down-regulated DEGs resulted implicated in cell migration or monocytes differentiation, both into macrophage and dendritic cells. Among the top down-regulated genes we observed CCR7 (padjusted= 3.1×10-30, FC=0.22), IL7R (padjusted= 1.98×10-23, FC=0.32) and AQP3 (padjusted= 4.85×10-21, FC=0.31). Pathway and subpath analyses confirmed an involvement of processes related with immune function and cell migration.
Conclusions: Our data suggest that FTY induces transcriptional changes on monocytes, down-regulating genes with cell migration functions and associated with monocytes differentiation.