Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Nutr. 2013 Mar;143(3):260-6. doi: 10.3945/jn.112.168617. Epub 2013 Jan 9.

Neuronal-specific iron deficiency dysregulates mammalian target of rapamycin signaling during hippocampal development in nonanemic genetic mouse models.

Author information

  • 1Department of Pediatrics, University of Minnesota School of Medicine, Minneapolis, MN, USA.

Abstract

Iron deficiency (ID) is the most common nutrient deficiency worldwide, disproportionally affecting infants, children, and women of childbearing age. Although ID commonly occurs with anemia (IDA), nonanemic ID is 3 times more common than IDA in toddlers and also occurs in infants following gestational complications. Both conditions negatively affect motor, socio-emotional, and cognitive behaviors, suggesting that iron, apart from anemia, has a critical role in neurodevelopment. Here, the specific role of iron in regulation of mammalian target of rapamycin (mTOR) signaling (a kinase pathway that integrates metabolic supply and demand to regulate cell growth and morphology) was examined using 2 hippocampal, pyramidal cell-specific, nonanemic, genetic mouse models of ID: a CAMKIIα cre-loxP permanent knockout of divalent metal transporter-1 (DMT-1 CKO) and a CAMKIIα-tTA-driven reversible, overexpression of nonfunctional, dominant negative transferrin receptor-1 (DN TfR-1). In both models, mTOR activity, assessed by phosphorylation levels of key proteins, was upregulated during development by ID [S6K(Thr389) phosphorylation increased 87 and 57% in the DMT-1 CKO and DN TfR-1 models, respectively; P < 0.05]. This effect was shown to be iron-dependent, because iron repletion at postnatal d 21 normalized mTOR activity in the reversible DN TfR-1 model (62% reduction compared with unrepleted mice; P < 0.05). In the permanent DMT-1 CKO model, suppression of ID-induced mTOR hyperactivity by rapamycin administered during the sensitive period for iron improved Morris water maze performance despite ongoing ID (DMT-1 wild-type and DMT-1 CKO mice reached criterion in 3 d compared with 4 d necessary for vehicle-treated DMT-1 CKO mice; P < 0.05). Together, these findings implicate mTOR dysregulation as a cellular mechanism underlying the acute and persistent neurodevelopmental deficits that accompany early-life ID.

PMID:
23303869
[PubMed - indexed for MEDLINE]
PMCID:
PMC3713018
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk