Murine arcuate nucleus kisspeptin neurons communicate with GnRH neurons in utero

TY - JOUR

T1 - Murine arcuate nucleus kisspeptin neurons communicate with GnRH neurons in utero

AU - Kumar, Devesh

AU - Freese, Maria

AU - Drexler, Dagmar

AU - Hermans-Borgmeyer, Irm

AU - Marquardt, Annette

AU - Boehm, Ulrich

PY - 2014/3/5

Y1 - 2014/3/5

N2 - Puberty is a transition period of reproductive development from juvenile stages to adulthood and depends upon the activity of gonadotropin-releasing hormone (GnRH) neurons. GnRH neurons are initially activated in utero but remain quiescent throughout the juvenile period. Premature reactivation of GnRH neurons results in precocious puberty in mice and humans, but the mechanisms underlying developmental control of GnRH neuron activity remain unknown. The neuropeptide kisspeptin, a potent activator of GnRH neurons that is implicated as a critical permissive signal triggering puberty and a major regulator of the adult female hypothalamus-pituitary-gonadal axis, is paradoxically produced by neurons in the developing brain well before puberty onset. Thus, the neural circuits controlling the timing of reproductive maturation remain elusive. Here, we delineate the underlying neural circuitry using conditional genetic transsynaptic tracing in female mouse embryos. We find that kisspeptin-producing neurons in the arcuate nucleus (ARC) already communicate with a specific subset of GnRH neurons in utero. We show that ARC kisspeptin neurons are upstream of GnRH neurons, and that GnRH neuron connectivity to ARC kisspeptin neurons does not depend on their spatial position in the brain. Furthermore, we demonstrate that the neural circuits between ARC kisspeptin and GnRH neurons are fully established and operative before birth. Finally, we find that most GnRH neurons express the kisspeptin receptor GPR54 upon circuit formation, suggesting that the signaling system implicated in gatekeeping puberty becomes operative in the embryo.

AB - Puberty is a transition period of reproductive development from juvenile stages to adulthood and depends upon the activity of gonadotropin-releasing hormone (GnRH) neurons. GnRH neurons are initially activated in utero but remain quiescent throughout the juvenile period. Premature reactivation of GnRH neurons results in precocious puberty in mice and humans, but the mechanisms underlying developmental control of GnRH neuron activity remain unknown. The neuropeptide kisspeptin, a potent activator of GnRH neurons that is implicated as a critical permissive signal triggering puberty and a major regulator of the adult female hypothalamus-pituitary-gonadal axis, is paradoxically produced by neurons in the developing brain well before puberty onset. Thus, the neural circuits controlling the timing of reproductive maturation remain elusive. Here, we delineate the underlying neural circuitry using conditional genetic transsynaptic tracing in female mouse embryos. We find that kisspeptin-producing neurons in the arcuate nucleus (ARC) already communicate with a specific subset of GnRH neurons in utero. We show that ARC kisspeptin neurons are upstream of GnRH neurons, and that GnRH neuron connectivity to ARC kisspeptin neurons does not depend on their spatial position in the brain. Furthermore, we demonstrate that the neural circuits between ARC kisspeptin and GnRH neurons are fully established and operative before birth. Finally, we find that most GnRH neurons express the kisspeptin receptor GPR54 upon circuit formation, suggesting that the signaling system implicated in gatekeeping puberty becomes operative in the embryo.

KW - Animals

KW - Arcuate Nucleus of Hypothalamus

KW - Female

KW - Gonadotropin-Releasing Hormone

KW - Mice

KW - Mice, 129 Strain

KW - Mice, Inbred C57BL

KW - Nerve Net

KW - Neurons

KW - Pregnancy

KW - Receptors, G-Protein-Coupled

U2 - 10.1523/JNEUROSCI.5123-13.2014

DO - 10.1523/JNEUROSCI.5123-13.2014

M3 - SCORING: Journal article

C2 - 24599473

VL - 34

SP - 3756

EP - 3766

JO - J NEUROSCI

JF - J NEUROSCI

SN - 0270-6474

IS - 10

ER -