The chemokine CCL17, produced by macrophages under GM-CSF control, drives inflammatory and arthritic pain through a pathway requiring nerve growth factor, CGRP, and substance P.
3 mediators requiredNGF, CGRP, and substance P are all necessary for CCL17-driven inflammatory pain
What the researchers found
A GM-CSF→CCL17 pathway in macrophages drives inflammatory pain through nerve growth factor, CGRP, and substance P signaling in non-bone-marrow-derived cells.
Why it matters
Identifying that CCL17 funnels through neuropeptides like CGRP and substance P to cause pain reveals multiple potential drug targets for inflammatory and arthritic pain.
The numbers in context
CCL17 from macrophages (GM-CSF-dependent); acts on CCR4+ non-BM cells; NGF, CGRP, substance P all required for pain
How the study worked
Multiple mouse inflammation and arthritis models using Ccl17 reporter mice, radiation chimeras, and pharmacological blockade of downstream mediators (NGF, CGRP, substance P).
Who was studied
CCL17 reporter mice and wild-type mice in inflammation/arthritis models
What this study cannot tell us
Mouse models only; group sizes not specified; the specific CCR4+ non-bone-marrow cells responding to CCL17 were not fully identified.
How to read the evidence
Moderate — robust mechanistic animal study using multiple models and reporter mice, but no human data.
When this study was published
Published in 2020; CGRP-targeting therapies have since expanded significantly.
The bigger picture
CGRP-blocking drugs (like migraine medications) and substance P antagonists already exist. Understanding how CCL17 engages these pathways could expand their use to arthritic and inflammatory pain.
Questions still open
- Would CGRP-blocking antibodies (used for migraine) also reduce CCL17-driven arthritic pain?
- Which specific non-bone-marrow cell types express CCR4 and mediate the pain response?
- Does this pathway operate similarly in human inflammatory conditions?
Common questions
What is CCL17?
How does this relate to CGRP migraine drugs?
Read the original research
CCL17 in Inflammation and Pain.
Journal of immunology (Baltimore, Md. : 1950), 205(1), 213-222
Citation
Lee, Kevin M-C; Jarnicki, Andrew; Achuthan, Adrian; Fleetwood, Andrew J; Anderson, Gary P; Ellson, Christian; Feeney, Maria; Modis, Louise K; Smith, Julia E; Hamilton, John A; Cook, Andrew. (2020). CCL17 in Inflammation and Pain.. Journal of immunology (Baltimore, Md. : 1950), 205(1), 213-222. https://doi.org/10.4049/jimmunol.2000315