Journal Article

Monocytes from inflammatory arthritis patients accumulate methotrexate and their transcriptome predicts methotrexate clinical response

Puig-Kröger, Amaya, Castrejón, Isabel, Schiaffino, María Teresa, Torres-Torresano, Mónica, López-Navarro, Baltasar, Álvarez, Susana, Román, Manuel, Struys, Eduard A., de Jonge, Robert, Castañeda, Santos, González-Álvaro, Isidoro, Triguero-Martínez, Ana, Garcia-Castañeda, Noelia, Lin, Marry, Abad-Santos, Francisco, Ríos, Israel, Jansen, Gerrit

2026

Overview

Monocytes and monocyte-derived macrophages play a key pathogenic role in inflammatory arthritis. Methotrexate (MTX) is the first-line disease-modifying antirheumatic drug (DMARD) for arthritis, yet the mechanisms and kinetics of its effects on monocyte/macrophages remain poorly understood. We have now investigated the temporal dynamics of the MTX's anti-inflammatory action by initially performing a phase I clinical trial (METOMAC) on healthy individuals following a single MTX dose, which revealed that MTX plasma levels peak at 1 h after MTX treatment, with maximal suppression of LPS-induced IL-1β and IL-6 in whole blood 5 days after MTX exposure. Building on these findings, we performed an observational clinical study (METOMAC-PAC) on 29 DMARD-naïve early arthritis patients receiving a weekly dose of MTX over a 3 month period. The METOMAC-PAC study revealed that MTX polyglutamates (MTX-PG) accumulates in peripheral blood monocytes, where MTX-PG is detected as early as 5 days post-treatment, and modulates the monocyte gene profile after 4 MTX doses, with specific enrichment of the aryl-hydrocarbon receptor (AhR)-molecular signature and genes coding for anti-inflammatory factors. Importantly, stratification of METOMAC-PAC patients according to their clinical response revealed that Good Responders exhibit increased expression of “non-classical monocyte”-specific genes ( MAF , FCGR3B , ICAM4 ) both before and after MTX treatment, while Partial Responders patients showed a higher baseline expression of genes preferentially expressed by “classical monocytes”. Our results elucidate the kinetics of the anti-inflammatory action of MTX, demonstrate that MTX modulates the monocyte transcriptional signature in vivo , and identify “non-classical monocyte”-associated genes as predictors for an effective MTX clinical response. Graphical abstract

• Publisher: Springer International Publishing,Springer Nature B.V,Springer
• Subject: Acids / Adult / Antirheumatic Agents - pharmacology / Antirheumatic Agents - therapeutic use / Arthritis / Arthritis - drug therapy / Arthritis - genetics / Arthritis - pathology / Arthritis, Rheumatoid - drug therapy / Aryl hydrocarbon receptor / Biochemistry / Biomedical and Life Sciences / Biomedicine / Blood / Cell Biology / Disease / Drug dosages / Fc receptors / Female / Genes / Health services / Hospitals / Humans / Inflammation / Inflammation - drug therapy / Inflammatory arthritis / Kinetics / Life Sciences / Macrophages / Male / Methotrexate / Methotrexate - analogs & derivatives / Methotrexate - blood / Methotrexate - pharmacology / Methotrexate - therapeutic use / Middle Aged / Monocytes / Monocytes - drug effects / Monocytes - metabolism / Original / Original Article / Patients / Peripheral blood / Pilot projects / Plasma levels / Proteins / Transcriptome - drug effects / Transcriptomes / Vitamin B