Reciprocal repulsions instruct the precise assembly of parallel hippocampal networks

Mammalian medial and lateral hippocampal networks preferentially process spatial- and object-related information, respectively. However, the mechanisms underlying the assembly of such parallel networks during development remain largely unknown. Our study shows that, in mice, complementary expression of cell surface molecules teneurin-3 (Ten3) and latrophilin-2 (Lphn2) in the medial and lateral hippocampal networks, respectively, guides the precise assembly of CA1-to-subiculum connections in both networks. In the medial network, Ten3-expressing (Ten3+) CA1 axons are repelled by target-derived Lphn2, revealing that Lphn2- and Ten3-mediated heterophilic repulsion and Ten3-mediated homophilic attraction cooperate to control precise target selection of CA1 axons. In the lateral network, Lphn2-expressing (Lphn2+) CA1 axons are confined to Lphn2+ targets via repulsion from Ten3+ targets. Our findings demonstrate that assembly of parallel hippocampal networks follows a Ten3 -> Ten3, Lphn2 -> Lphn2 rule instructed by reciprocal repulsions.

Automated summary

The study reveals that in mice, the complementary expression of cell surface molecules teneurin-3 (Ten3) and latrophilin-2 (Lphn2) guides the precise assembly of CA1-to-subiculum connections in the medial and lateral hippocampal networks. The repulsion and attraction mechanisms mediated by Lphn2 and Ten3 cooperate to control the target selection of CA1 axons. The assembly of parallel hippocampal networks follows a Ten3 -> Ten3, Lphn2 -> Lphn2 rule instructed by reciprocal repulsions.