Related Experiment Video

Updated: Jul 15, 2026

Mouse Model of Alloimmune-induced Vascular Rejection and Transplant Arteriosclerosis
07:05

Mouse Model of Alloimmune-induced Vascular Rejection and Transplant Arteriosclerosis

Published on: May 17, 2015

Syk from M1 macrophage exosomes drives vascular injury in kidney transplant rejection

Jinxu Miao1, Yuxi Chen1, Zhou Hang1

  • 1Department of Urology, Jiangsu Key Laboratory of Urological Disease Prevention and Treatment, The Second Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China.

Transplant Immunology
|July 13, 2026
PubMed

Insights

M1 macrophage exosomes, enriched with spleen tyrosine kinase (Syk), drive kidney transplant rejection by activating endothelial cells. Inhibiting Syk in these exosomes reduces vascular injury and rejection signs.

Area of Science:

  • Immunology
  • Transplantation Biology
  • Cell Biology

Background:

  • Antibody-mediated rejection (ABMR) is a major cause of kidney transplant failure, involving inflammation and damage to blood vessels.
  • M1-polarized macrophages accumulate in rejected allografts, but their exosomes' role in vascular injury is unclear.

Purpose of the Study:

  • To investigate the role of exosomes secreted by M1 macrophages (M1-Exos) in endothelial injury during ABMR.
  • To identify specific molecules within M1-Exos mediating this vascular damage.

Main Methods:

  • Transcriptomic and proteomic analysis of M1-Exos to identify key proteins.
  • In vitro functional assays using endothelial cells to assess M1-Exo effects.
  • Inhibition and genetic deletion of identified proteins (Syk) to determine their role.
  • Murine model of renal transplantation to evaluate M1-Exo effects in vivo.

Main Results:

  • M1-Exos significantly induce endothelial activation, upregulating ICAM-1 and VCAM-1.
  • Spleen tyrosine kinase (Syk) was identified as highly enriched in M1-Exos.
  • Exosomal Syk transfer to endothelial cells activates the NLRP3 inflammasome and caspase-1.
  • Inhibition or absence of Syk in M1-Exos reduced endothelial inflammation and ABMR severity in a murine model.

Conclusions:

  • Exosomes derived from M1 macrophages mediate endothelial inflammation and vascular injury in ABMR.
  • Exosomal Syk is a key mediator, transferred from M1 macrophages to endothelial cells, driving inflammasome activation.
  • Targeting exosomal Syk presents a potential therapeutic strategy for mitigating ABMR and improving transplant outcomes.
Keywords:
Acute rejectionExosomeInflammation injuryKidney transplantationMacrophage polarizationSyk

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