Frontiers in Molecular Neuroscience (Sep 2023)

Brain cell-specific origin of circulating microRNA biomarkers in experimental temporal lobe epilepsy

  • Elizabeth Brindley,
  • Mona Heiland,
  • Mona Heiland,
  • Catherine Mooney,
  • Catherine Mooney,
  • Mairead Diviney,
  • Omar Mamad,
  • Omar Mamad,
  • Thomas D. M. Hill,
  • Thomas D. M. Hill,
  • Yan Yan,
  • Yan Yan,
  • Morten T. Venø,
  • Morten T. Venø,
  • Cristina R. Reschke,
  • Cristina R. Reschke,
  • Aasia Batool,
  • Elena Langa,
  • Elena Langa,
  • Amaya Sanz-Rodriguez,
  • Amaya Sanz-Rodriguez,
  • Janosch P. Heller,
  • Janosch P. Heller,
  • Janosch P. Heller,
  • Gareth Morris,
  • Gareth Morris,
  • Gareth Morris,
  • Gareth Morris,
  • Karen Conboy,
  • Karen Conboy,
  • Jørgen Kjems,
  • Gary P. Brennan,
  • Gary P. Brennan,
  • David C. Henshall,
  • David C. Henshall

DOI
https://doi.org/10.3389/fnmol.2023.1230942
Journal volume & issue
Vol. 16

Abstract

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The diagnosis of epilepsy is complex and challenging and would benefit from the availability of molecular biomarkers, ideally measurable in a biofluid such as blood. Experimental and human epilepsy are associated with altered brain and blood levels of various microRNAs (miRNAs). Evidence is lacking, however, as to whether any of the circulating pool of miRNAs originates from the brain. To explore the link between circulating miRNAs and the pathophysiology of epilepsy, we first sequenced argonaute 2 (Ago2)-bound miRNAs in plasma samples collected from mice subject to status epilepticus induced by intraamygdala microinjection of kainic acid. This identified time-dependent changes in plasma levels of miRNAs with known neuronal and microglial-cell origins. To explore whether the circulating miRNAs had originated from the brain, we generated mice expressing FLAG-Ago2 in neurons or microglia using tamoxifen-inducible Thy1 or Cx3cr1 promoters, respectively. FLAG immunoprecipitates from the plasma of these mice after seizures contained miRNAs, including let-7i-5p and miR-19b-3p. Taken together, these studies confirm that a portion of the circulating pool of miRNAs in experimental epilepsy originates from the brain, increasing support for miRNAs as mechanistic biomarkers of epilepsy.

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