RGD-modified TREX1-loaded EVs attenuate neuroinflammation and improve recovery after ischemic stroke
Background
Ischemic stroke is a leading cause of global mortality and permanent functional deficits, with current interventions severely limited by post-ischemic neuroinflammation. Cerebral ischemic injury triggers an inflammatory surge driven by the cGAS-STING signaling cascade, initiated by cytosolic DNA. Three-prime repair exonuclease 1 (TREX1), a cytosolic DNA exonuclease, negatively regulates STING signaling, but its efficient delivery to the ischemic brain remains a significant challenge. This study addresses the need for targeted delivery of anti-inflammatory agents to improve stroke outcomes.
Study Design
Researchers engineered mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) to deliver TREX1. They created a palmitoylation signal-fused construct (PALM-TREX1) for efficient protein loading into EVs. For targeted delivery, the C1C2 domains of lactadherin and the RGD-4C peptide were fused, enabling EV surface functionalization for enhanced ischemic targeting via phosphatidylserine interaction. In a mouse model of middle cerebral artery occlusion (MCAO), RGD-EV-TREX1 was administered, and its accumulation, STING pathway activation, microglial activation, pro-inflammatory cytokine expression, neuronal DNA damage, apoptosis, and neurological functional recovery were assessed.
Results
RGD-modified TREX1-loaded EVs (RGD-EV-TREX1) demonstrated preferential accumulation in ischemic regions of the mouse brain. This targeted delivery led to a significant suppression of STING pathway activation, which is critical in post-ischemic inflammation.
The intervention also markedly reduced microglial activation and the expression of pro-inflammatory cytokines, indicating a potent anti-neuroinflammatory effect. Furthermore, RGD-EV-TREX1 treatment resulted in a reduction in neuronal DNA damage and decreased apoptosis, protecting brain cells from secondary injury. Ultimately, these cellular and molecular improvements facilitated improved neurological functional recovery in the
MCAOmouse model, highlighting the therapeutic potential of this engineered EV strategy for ischemic stroke.
Key Findings
- Engineered RGD-EV-TREX1 preferentially accumulated in ischemic brain regions in a mouse
MCAOmodel. - Treatment with RGD-EV-TREX1 suppressed
STINGpathway activation in the ischemic brain. - RGD-EV-TREX1 reduced microglial activation and pro-inflammatory cytokine expression.
- Neuronal DNA damage and apoptosis were reduced following RGD-EV-TREX1 administration.
- RGD-EV-TREX1 treatment ultimately facilitated improved neurological functional recovery.
Why It Matters
This research introduces a novel, cell-free therapeutic strategy for ischemic stroke that overcomes the challenge of targeted delivery for anti-inflammatory agents like TREX1. By engineering EVs with specific targeting peptides, it's possible to concentrate the therapeutic payload where it's most needed, potentially reducing systemic side effects. This approach offers a promising avenue for developing more effective treatments for neuroinflammation post-stroke, moving beyond current limitations. While preclinical, it lays the groundwork for future clinical translation, suggesting that engineered EVs could become a key component in neuroprotective and regenerative medicine, potentially influencing future protocols for acute stroke management.
trex1
extracellular-vesicles
ischemic-stroke
neuroinflammation
cgas-sting
mcao