Intrahippocampal Inoculation of Aβ1-42 Peptide in Rat as a Model of Alzheimer's Disease Identified MicroRNA-146a-5p as Blood Marker with Anti-Inflammatory Function in Astrocyte Cells

Cells. 2023 Feb 22;12(5):694. doi: 10.3390/cells12050694.

Abstract

Circulating microRNAs (miRNAs) have aroused a lot of interest as reliable blood diagnostic biomarkers of Alzheimer's disease (AD). Here, we investigated the panel of expressed blood miRNAs in response to aggregated Aβ1-42 peptides infused in the hippocampus of adult rats to mimic events of the early onset of non-familial AD disorder. Aβ1-42 peptides in the hippocampus led to cognitive impairments associated with an astrogliosis and downregulation of circulating miRNA-146a-5p, -29a-3p, -29c-3p, -125b-5p, and-191-5p. We established the kinetics of expression of selected miRNAs and found differences with those detected in the APPswe/PS1dE9 transgenic mouse model. Of note, miRNA-146a-5p was exclusively dysregulated in the Aβ-induced AD model. The treatment of primary astrocytes with Aβ1-42 peptides led to miRNA-146a-5p upregulation though the activation of the NF-κB signaling pathway, which in turn downregulated IRAK-1 but not TRAF-6 expression. As a consequence, no induction of IL-1β, IL-6, or TNF-α was detected. Astrocytes treated with a miRNA-146-5p inhibitor rescued IRAK-1 and changed TRAF-6 steady-state levels that correlated with the induction of IL-6, IL-1β, and CXCL1 production, indicating that miRNA-146a-5p operates anti-inflammatory functions through a NF-κB pathway negative feedback loop. Overall, we report a panel of circulating miRNAs that correlated with Aβ1-42 peptides' presence in the hippocampus and provide mechanistic insights into miRNA-146a-5p biological function in the development of the early stage of sporadic AD.

Keywords: Alzheimer’s disease; Aβ1–42 peptide; biomarkers; diagnosis; miRNA-146a-5p; microRNAs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alzheimer Disease* / metabolism
  • Animals
  • Anti-Inflammatory Agents / metabolism
  • Astrocytes / metabolism
  • Interleukin-6 / metabolism
  • Mice
  • MicroRNAs* / metabolism
  • NF-kappa B / metabolism
  • Rats

Substances

  • amyloid beta-protein (1-42)
  • Anti-Inflammatory Agents
  • Interleukin-6
  • MicroRNAs
  • NF-kappa B
  • MIRN146a microRNA, rat

Grants and funding

This research was funded by CNRS and the University of Orléans. R.A. received a fellowship from the Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica (CONCYTEC), Cayetano Heredia Peruvian University, and the University of Orléans, through the French-Peruvian PhD program in Life Sciences. This work was also supported by European funding in Région Centre-Val de Loire (FEDER No. EX016008 TARGET-EX).