Search bioRxiv⌕ Search

Biology subjects

Faour, M.

Publications and source records attributed to Faour, M..

2 recordsLinked to original sources

Parathyroid Hormone Receptor 1 Signaling Encodes Multifaceted Metabolic Programs in AgRP Neurons

Organisms continuously adapt food intake and nutrient utilization to fluctuating energy demands, requiring the brain to accurately integrate signals coming from diverse metabolic organs and local signals into distinct physiological responses. How hypothalamic neurons discriminate these signals to independently regulate feeding behavior and peripheral metabolism remains poorly understood. In recent years, a coordinated regulation between bone physiology and the central control of energy metabolism has emerged, opening questions about potential common hormonal networks and signaling pathways between the bone and the brain. Here, we identify parathyroid hormone receptor 1 (PTH1R) signaling, a master regulator of calcium ion biochemistry and bone formation, in Agouti-related peptide (AgRP) neurons as an unexpected neuroendocrine mechanism for the control of feeding behaviourand nutrient partitioning. the two cognate endocrine and paracrine ligands, PTH and PTH-related peptide (PTHrP), selectively activat segregated intracellular kinases activation and lipophagic processes in AgRP neuron, ultimately producing convergent physiological outputs. Together, our findings identify the parathyroid hormonal system acts as a fine-tuning mechanism in specialized neuronal circuits allowing for hypothalamic adaptive responses to energy demands and systemic metabolic signals. Keywords: Parathyroid hormone-related peptide (PTHrP), hypothalamus, arcuate nucleus, agouti-related peptide neurons, energy metabolism, fasting, autophagy, free fatty acids

neuroscience↗

CaMK1D signaling in AgRP neurons promotes ghrelin-mediated food intake

Hypothalamic AgRP/NPY neurons are key players in the control of feeding behavior. Ghrelin, a major hormone released under fasting conditions, activates orexigenic AgRP/NPY neurons to stimulate food intake and adiposity. However, cell-autonomous ghrelin-dependent signaling mechanisms in AgRP/NPY neurons remain poorly defined. Here we demonstrate that calcium/calmodulin-dependent protein kinase ID (CaMK1D), a genetic hot spot in type 2 diabetes, is activated in hypothalamus upon ghrelin stimulation and acts in AgRP neurons to promote ghrelin-dependent food intake. Global CaMK1D knockout mice are resistant to the orexigenic action of ghrelin, gain less body weight and are protected against high-fat diet-induced obesity. Deletion of CaMK1D in AgRP but not in POMC neurons is sufficient to recapitulate above phenotypes. Lack of CaMK1D attenuates phosphorylation of CREB and CREB-dependent expression of the orexigenic neuropeptides AgRP/NPY as well as the amount of AgRP fiber projections to the Paraventricular nucleus (PVN), while electrical activity of AgRP neurons and 5 AMP-activated protein kinase (AMPK) signaling are unaffected. Hence, CaMK1D links ghrelin action to transcriptional control of orexigenic neuropeptide availability in AgRP neurons. HighlightsO_LIWhole-body deletion of CaMK1D in mice reduces food intake, ghrelin sensitivity and protects against obesity. C_LIO_LIAgRP/NPY neuron-specific deletion of CaMK1D reduces food intake, ghrelin sensitivity, energy expenditure and protects against obesity. C_LIO_LICaMK1D is dispensable for ghrelin-stimulated electrical activity of AgRP neurons and hypothalamic AMPK signaling. C_LIO_LICaMK1D controls phosphorylation of CREB and CREB-dependent expression of the orexigenic neuropeptides AgRP and NPY. C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=174 HEIGHT=200 SRC="FIGDIR/small/471546v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@40d7d7org.highwire.dtl.DTLVardef@11a8c64org.highwire.dtl.DTLVardef@1f6fad3org.highwire.dtl.DTLVardef@1cd5581_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗