Loss of the neurodevelopmental disease-associated gene miR-146a impairs neural progenitor differentiation and causes learning and memory deficits.
Julien Fregeac, Stéphanie Moriceau, Antoine Poli and 3 others
PMID 32228681WHAT IT FOUND
Mouse loss of miR-146a shifted early neural progenitor balance, increased hippocampal asymmetry, and impaired fear, object, and location memory.
It is a basic mechanism study, not evidence for human therapy.
Key findings
01In E14.5 mutant mouse cortex, miR-146a loss produced a 10% decrease of PAX6+ cells and a 10% increase of TBR2+ cells compared with controls.
02miR-146a loss impaired hippocampal-dependent spatial learning and memory, episodic memory, and associative fear memory, independent of inflammation.
03Selective adult hippocampal knockdown of miR-146a caused behavioral deficits and a drastic decrease of DCX+ cells in the dentate gyrus.
STILL TO COME
How it was doneWhat they found
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What it does not show
This is a mouse mechanistic study, not a human rehabilitation trial, so it does not test therapy or patient outcomes. The MRI group was small and sex-mismatched: four mutant mice were males, while controls included one female and two males. Mice were analyzed before 6 months to avoid inflammatory disease signs, so later disease states were not modeled. The paper does not establish the mechanism by which miR-146a loss causes defective neuronal differentiation. Adult hippocampal knockdown used viral shRNA in normal mice, so it does not show what happens in human development or therapy.
Declared interests
Funding was from Fondation pour Recherche Médicale, Crédit Agricole d'Ile-de-France Mécénat, Fondation pour la Recherche Médicale, Ville de Paris, Fondation Schlumberger pour l’Education et la Recherche, and Agence Nationale de la Recherche. The supplied text does not state author conflicts of interest.
The easy way to misread this
Do not read the mouse learning and memory deficits as evidence that miR-146a testing or manipulation can guide human therapy. The study used genetically modified mice, embryonic tissue, MRI, and direct hippocampal virus injections, not patients or rehabilitation outcomes.