CAV2-Cre was used to determine whether iron transported from the vHip to the mPFC travels specifically in vHip–mPFC projections, AAV- EGFP- SLC40A1 was used to examine the effect of overexpressing FPN in the vHip–mPFC projections. (All viruses were packaged by BrainVTA)

CRE Recombinase	PT-0136 AAV2-RETRO-hSyn-Cre  PT-0025 AAV2/9-CMV-Cre-pA
Control	PT-0099 AAV2-RETRO-EF1α-mCherry  PT-0098 AAV2-RETRO-EF1α-EGFP  PT-0142 AAV2/9-CMV-EGFP  AAV2/9-CMV-DIO-EGFP-T2A
Custom-Made AAVs	AAV2/9-CMV-DIO-EGFP-T2A-SLC40A1
CAV	C000101 CAV2-CMV-Cre

Pub Date: 2019-10-07,  DOI: 10.1038/s41589-019-0371-x Email: [email protected]
Zhuo Wang, Yuan-Ning Zeng, Peng Yang, Li-Qiang Jin, Wen-Chao Xiong, Min-Zhen Zhu, Jun-Zhe Zhang, Xiao He and Xin-Hong Zhu Iron is essential for a broad range of biochemical processes in the brain, but the mechanisms of iron metabolism in the brain remain elusive. Here we show that iron functionally translocates among brain regions along specific axonal projections. We identified two pathways for iron transport in the brain: a pathway from ventral hippocampus (vHip) to medial prefrontal cortex (mPFC) to substantia nigra; and a pathway from thalamus (Tha) to amygdala (AMG) to mPFC. While vHip–mPFC transport modulates anxiety-related behaviors, impairment of Tha–AMG–mPFC transport did not. Moreover, vHip–mPFC iron transport is necessary for the behavioral effects of diazepam, a well-known anxiolytic drug. By contrast, genetic or pharma-cological promotion of vHip–mPFC transport produced anxiolytic-like effects and restored anxiety-like behaviors induced by repeated restraint stress. Taken together, these findings provide key insights into iron metabolism in the brain and identify the mechanisms underlying iron transport in the brain as a potential target for development of novel anxiety treatments.