# Endothelial‐Targeted Metallothionein‐2 shRNA Nanoparticles Alleviate Migraine‐Like Symptoms

## TL;DR

This study shows that reducing Mt2 in blood vessel cells using nanoparticles can ease migraine symptoms like light sensitivity and pain in mice.

## Contribution

The study identifies Mt2 in endothelial cells as a novel therapeutic target for migraine treatment.

## Key findings

- Mt2 is significantly upregulated in vascular endothelial cells during migraine.
- Downregulating Mt2 with shRNA nanoparticles reduces migraine-related behaviors and vasodilation.
- Mt2 suppression decreases NO production and neuroinflammation markers in migraine models.

## Abstract

Migraine is a common chronic neurological disorder manifesting as recurrent moderate‐to‐severe headaches. It continues to present therapeutic challenges due to population heterogeneity in treatment response. This study investigates the unexplored role of metallothionein‐2 (Mt2) in migraine pathophysiology.

We employed the EGR1‐GFP reporter system to identify activated cortical cells induced by nitroglycerin (NTG). RNA sequencing of somatosensory activated cortex cells revealed marked Mt2 upregulation particularly in vascular endothelial cells. To elucidate Mt2's function in migraine pathogenesis, endothelial‐targeted nanoparticles encapsulating Mt2‐shRNA were engineered and administered via tail‐vein injection in migraine model mice. Behavioral assays assessed photophobia and hyperalgesia, while two‐photon microscopy evaluated cerebral vasodilation. Pathway enrichment analysis identified critical biological pathways linked to Mt2 activity.

Suppression of Mt2 in endothelial cells via shRNA nanoparticles alleviated migraine‐related behaviors, including photophobia and hyperalgesia. RNA‐seq and pathway analysis highlighted Mt2's involvement in cerebrovascular endothelial cell development, migration, and inflammation pathways. Crucially, two‐photon imaging demonstrated that downregulation of Mt2 markedly attenuated NTG‐induced cerebral vasodilation.

This study establishes Mt2 as a regulator of vascular tone and inflammatory signaling in migraine pathogenesis, proposing novel therapeutic targets. These findings provide insight in understanding the interplay between vascular dysfunction and migraine.

This schematic illustrates the therapeutic effects of endothelial‐targeted Mt2‐shRNA nanoparticles in a migraine model. In saline‐treated controls (Normal), cerebral vasculature remains balanced. Nitroglycerin (NTG) triggers pathological vasodilation in the migraine mice model, accompanied by elevated Mt2, nitric oxide (NO), and pro‐inflammatory markers (CGRP, IL‐6, TNF‐α), alongside neuronal activation. Administration of Mt2‐shRNA nanoparticles reverses these effects: Mt2 suppression reduces NO production via NOS2 downregulation, normalizes vascular tone, and attenuates neuroinflammation. Concurrently, activated neurons decrease, demonstrating dual modulation of cerebrovascular dysfunction and inflammatory signaling. Two‐photon imaging validates restored vascular dynamics, highlighting Mt2 as a pivotal therapeutic target for migraine intervention.