Deciphering molecular inputs to CRH neurons from POMC neurons

Area of Science:

• Neuroscience
• Endocrinology
• Molecular Biology

Background:

• Stress hormones play a crucial role in energy balance and survival behaviors.
• Proopiomelanocortin (POMC) neurons in the arcuate nucleus (ARC) influence satiety and autonomic responses.
• Corticotropin-releasing hormone neurons (CRHNs) in the paraventricular nucleus (PVN) are activated during stress.

Purpose of the Study:

• To elucidate the neurotransmitter-based regulatory mechanisms between POMC and CRHNs.
• To investigate the role of glutamatergic signaling in POMC-CRHNs interactions.
• To explore the evolutionary conservation of this neural circuit.

Main Methods:

• Analysis of single-cell RNA sequencing (scRNA-seq) datasets from mouse and human hypothalamus.
• Viral tracing experiments in mice to track neuronal activation and connectivity.
• Comparative analysis of gene expression patterns related to neurotransmission.

Main Results:

• Single-cell RNA sequencing revealed a dominant glutamatergic signaling pathway between POMC and CRHNs.
• Human hypothalamic data confirmed the prevalence of glutamatergic over GABAergic signaling.
• Viral tracing supported that restraint-activated POMC neurons predominantly express glutamatergic genes.

Conclusions:

• Glutamatergic signaling is the primary mode of communication from POMC neurons to CRHNs.
• This POMC-CRHNs glutamatergic interaction modulates the autonomic stress response.
• The findings highlight conserved molecular mechanisms in stress-responsive hypothalamic networks across species.