135: The role of Leukaemia Inhibitory Factor in Inflammatory Arthritis Pain

Topic: Basic Science
Subtopic: Pain category (ICD-11), Chronic secondary musculoskeletal pain, , , , , , , , , , Pharmacological interventions, Assessment and Measurement of Pain/Nociception, Behavioral studies

Background and Aims: The development of disease-modifying anti-rheumatic drugs (DMARDs) has been revolutionary for the treatment of Rheumatoid Arthritis (RA). However, many patients continue to experience pain despite reduced inflammation. One treatment that has shown promise in treating RA pain is JAK inhibition (JAKi), however concerns over potential cardiovascular and oncogenic side effects have been raised, limiting prescription(1). Cytokines upstream of the JAK-STAT pathway, such as Leukaemia Inhibitory Factor (LIF) and Interleukin 6 (IL-6) are enriched in RA Synovial Fluid and can induce JAK-STAT pathway activation in cultured human sensory neurones(2). Here we investigate the potential role of LIF in RA pain.

Methods: Stem cells (IPSC, one male and one female line) were differentiated into sensory neurons using the Chambers protocol(3). Three separate differentiations each were treated with LIF (100ng/ml) +/- JAKi (tofacitinib, 2µM) or IL-6 (100ng/ml) +/- JAKi. RNA was extracted and sequenced (30M, 150bp, PE reads).
The antigen-induced arthritis (AIA) mouse model was induced using standard protocols(4) and joint inflammation was assayed using joint thickness. An ELISA was used to measure LIF in the supernatant of digested mouse knee tissue.
Finally, LIF will be injected intraarticularly into healthy mouse knees. The weight-bearing assay will be used to assess joint pain levels.

Results: Using RNAseq, we found that LIF upregulates transcripts related to neuronal hyperexcitability in human sensory neurons in vitro and that this effect is inhibited by addition of the JAKi, tofacitinib. IL-6 upregulated only a subset of the same transcripts, indicating that LIF has a superior capacity to induce intracellular sensory neuron activation.
In mice, LIF concentration was shown to be significantly enriched in inflamed knees following AIA. The effects of LIF on mouse behaviour will be reported at the congress.

Conclusions: Recent published results from our group suggest that LIF is elevated in inflamed joints and may play a role in neuronal hyperexcitability(2). Here we investigated this further, revealing that LIF administration drastically affects the neuronal transcriptome, dysregulating genes related to sensory neuron hyper-excitability and peripheral sensitisation. We also show that AIA in mice results in clear enrichment of LIF protein in inflamed joints. Our aim is to further study whether LIF drives pain behaviours in vivo. Targeting LIF may be a strategy to recapitulate or improve on the analgesic effects of JAKi, increasing efficacy and/or reducing side effects.

References: (1) Rutter-Locher, Z., et al., An interdisciplinary perspective on peripheral drivers of pain in rheumatoid arthritis. Nat Rev Rheumatol, 2024. 20(11): p. 671-682.
(2) Li, Y., et al., Rheumatoid arthritis synovial fluid induces JAK-dependent intracellular activation of human sensory neurons. JCI Insight, 2025. 10(12).
(3) Chambers, S.M., et al., Combined small-molecule inhibition accelerates developmental timing and converts human pluripotent stem cells into nociceptors. Nat Biotechnol, 2012. 30(7): p. 715-20.
(4) Goodwin, G., et al., Antigen induced arthritis in mice. Protocols.io, 2024. DOI: dx.doi.org/10.17504/protocols.io.36wgqnp9ogk5/v1

All work was funded by a Wellcome Trust Collaborative Award (224257/Z/21/Z)

Presenting Author: Julia Vlachaki Walker
Submitting Author: Julia Vlachaki Walker

Senior Author: Franziska Denk

IASP 2026 Global Year theme of Neuropathic Pain: No

• Yuening Li - Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
• Rosie Ross - Centre for Inflammation Biology & Cancer Immunology, Department of Inflammation Biology, School of Immunology & Microbial Sciences
• Alina-Cristina Marin - Wolfson Sensory, Pain and Regeneration Centre (SPaRC), Guy's Campus
• Irene Zebochin - Wolfson Sensory, Pain and Regeneration Centre (SPaRC), Guy's Campus
• Teodora Trendafilova - Wolfson Sensory, Pain and Regeneration Centre (SPaRC), Guy's Campus
• Leonie S Taams - Centre for Inflammation Biology & Cancer Immunology, Department of Inflammation Biology, School of Immunology & Microbial Sciences
• Franziska Denk - Wolfson Sensory, Pain and Regeneration Centre (SPaRC), Guy's Campus