Immune Cells Enter the Brain After Stroke and Promote Blood Vessel Repair via CGRP | Research

The takeaway

ILC2 immune cells infiltrate the brain after stroke and promote new blood vessel growth through α-CGRP production, improving long-term recovery.

α-CGRP
Produced by brain-infiltrating ILC2s to initiate angiogenic sprouting after ischemic stroke

What the researchers found

ILC2s infiltrate the brain post-stroke via CXCR1 and produce α-CGRP that initiates angiogenic sprouting, improving long-term functional recovery.

Why it matters

Stroke recovery options are limited — harnessing the brain's own immune repair system through ILC2s and CGRP could open new therapeutic pathways.

The numbers in context

ILC2s enter brain parenchyma via CXCR1 after ischemic stroke. Alpha-CGRP production by ILC2s required for angiogenic sprouting. CGRP-depleted ILC2s failed to initiate angiogenesis. CGRP receptor impairment on endothelial cells abolished the effect.

How the study worked

In vivo and in vitro ILC2 expansion studies in ischemic stroke mouse models with functional recovery assessment.

Who was studied

Mouse ischemic stroke model

What this study cannot tell us

Mouse model study — human stroke pathophysiology and immune responses may differ. In vivo ILC2 expansion techniques are not yet clinically available.

How to read the evidence

Preclinical mouse study with robust mechanistic evidence — highly informative but requires human translation.

When this study was published

Published in 2025, revealing a novel neuroimmune repair mechanism post-stroke.

The bigger picture

This reveals CGRP as a brain repair molecule (not just a migraine target), expanding our understanding of how the immune and vascular systems collaborate after brain injury.

Questions still open

Could boosting ILC2 numbers or CGRP levels after stroke improve human outcomes?
Do anti-CGRP migraine drugs interfere with stroke recovery?

Common questions

How do immune cells help repair the brain after stroke?

ILC2 cells enter the brain from the bloodstream and produce CGRP, which triggers new blood vessel growth essential for recovery.

Could this discovery lead to new stroke treatments?

Potentially — boosting ILC2 activity or CGRP production after stroke could become a therapeutic strategy, but human studies are needed first.

Read the original research

Brain-infiltrating ILC2s boost poststroke angiogenic initiation through α-CGRP production.

The Journal of experimental medicine, 222(11)

View on PubMed ↗Publisher’s paper ↗

Citation

Ping, An; Yang, Fan; Lu, Lingxiao; Zhang, Xiaotao; Lu, Jianan; Li, Huaming; Gu, Yichen; Jin, Ziyang; Zhang, Jianmin; Shi, Ligen. (2025). Brain-infiltrating ILC2s boost poststroke angiogenic initiation through α-CGRP production.. The Journal of experimental medicine, 222(11). https://doi.org/10.1084/jem.20241830