Research Paper Volume 13, Issue 2 pp 3060—3079

Human umbilical cord mesenchymal stem cell-derived exosomal miR-146a-5p reduces microglial-mediated neuroinflammation via suppression of the IRAK1/TRAF6 signaling pathway after ischemic stroke

Zhongfei Zhang1, *, , Xiaoxiong Zou1, *, , Run Zhang1, *, , Yu Xie1, , Zhiming Feng1, , Feng Li1, , Jianbang Han1, , Haitao Sun1, , Qian Ouyang1, , Shiting Hua1, , Bingke Lv1, , Tian Hua1, , Zhizheng Liu1, , Yingqian Cai1, , Yuxi Zou1, , Yanping Tang1, , Xiaodan Jiang1,2, ,

  • 1 Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, The National Key Clinical Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Guangzhou, China
  • 2 Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou, China
* Equal contribution

Received: February 1, 2020       Accepted: September 9, 2020       Published: January 21, 2021
How to Cite

Copyright: © 2021 Zhang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


To investigate the therapeutic mechanism of action of transplanted stem cells and develop exosome-based nanotherapeutics for ischemic stroke, we assessed the effect of exosomes (Exos) produced by human umbilical cord mesenchymal stem cells (hUMSCs) on microglia-mediated neuroinflammation after ischemic stroke. Our results found that injected hUMSC-Exos were able to access the site of ischemic damage and could be internalized by cells both in vivo and in vitro. In vitro, treatment with hUMSC-Exos attenuated microglia-mediated inflammation after oxygen-glucose deprivation (OGD). In vivo results demonstrated that treatment with hUMSC-Exos significantly reduced infarct volume, attenuated behavioral deficits, and ameliorated microglia activation, as measured three days post-transient brain ischemia. Furthermore, miR-146a-5p knockdown (miR-146a-5p k/d Exos) partially reversed the neuroprotective effect of hUMSC-Exos. Our mechanistic study demonstrated that miR-146a-5p in hUMSC-Exos reduces microglial-mediated neuroinflammatory response through IRAK1/TRAF6 pathway. We conclude that miR-146a-5p derived from hUMSC-Exos can attenuate microglia-mediated neuroinflammation and consequent neural deficits following ischemic stroke. These results elucidate a potential therapeutic mechanism of action of mesenchymal stem cells and provide evidence that hUMSC-Exos represent a potential cell-free therapeutic option for ischemic stroke.


hUMSC: human umbilical cord mesenchymal stem cell; Exos: exosomes; IRAK1: interleukin-1 receptor-associated kinase 1; TRAF6: TNF receptor-associated factor 6; MCAO: middle cerebral artery occlusion; PBS: phosphate-buffered saline; TTC: 2,3,5-triphenyltetrazolium chloride; FBS: fetal bovine serum; OGD: oxygen-glucose deprivation; ECL: enhanced chemiluminescence; H&E: hematoxylin and eosin; siRNA: small interfering RNA.