Project description:Neuroendocrine regulation is essential for maintaining metabolic homeostasis. However, whether neuroendocrine pathway influence bone metabolism is unelucidated. Here, we identify a central neuroendocrine circuit that directly controls osteogenesis. Using virus based tracing, weidentify that melanin concentrating hormone (MCH) expressing neuronsin the lateral hypothalamus (LH) are connected to the bone.Chemogenetic activation of MCH neurons in the LH induces osteogenesis, whereas inhibiting these neurons reduces osteogenesis.Meanwhile, MCH is released into the circulation upon chemogenetic activation of these neurons. Single cell sequencing reveals that blocking MCH neurons in the LH diminishes osteogenic differentiation of bone marrow stromal cells (BMSCs). Mechanistically, MCH promotes BMSC differentiation by activating MCHR1 via PKA signaling and activating MCHR1 by MCH agonists attenuate osteoporosis in mice. By elucidating a brain-bone connection that autonomously enhances osteogenesis, these findings uncover the neuroendocrinological mechanisms governing bone mass regulation.
Project description:Imprinted genes are highly expressed in the hypothalamus, however whether specific imprinted genes affect hypothalamic neuromodulators and their functions is unknown. It has been suggested that Prader-Willi syndrome (PWS), a neurodevelopmental disorder caused by lack of paternal expression at the chromosome 15q11-q13, characterised with a hypothalamic insufficiency. Here we investigate the role of paternally expressed Snord116 gene within the context of sleep and metabolic abnormalities of PWS, and we report a novel role of this imprinted gene in the function and organisation of the two main neuromodulatory systems of the lateral hypothalamus (LH), namely the orexin (OX) and the melanin concentrating hormone (MCH). We observe that the dynamic between neuronal discharge in the LH and sleep-wake states of mice carrying the paternal deletion of the Snord116 (PWScrm+/p-) is compromised. This abnormal state-dependent neuronal activity is paralleled by a significant reduction of OX neurons in LH of mutants. Therefore, we propose that unbalance between OX- and MCH- expressing neurons in the LH of mutants reflects in a series of deficits manifested in the PWS, such as dysregulation of rapid eye movement (REM) sleep, food intake and temperature control.
Project description:We report phosphoRiboTrap experiments result which aim to explore the nature of the cell types in the Median Eminence (ME) regulated as a consequene of chemogenetic MCH neuron activation. Control and MCH-hM3Dq mice were 12 hrs-fasted and i.p. injected with CNO (3 mg/kg), Arcuate (ARC) and median eminence expat were extracted for preciptation of S6-marked ribosomes from both groups of mice. Extracted RNA from Immunoprecipitated ribosomes (IP) and total tissue (ARC+ME) from each mouse were subjected to deep mRNA sequencing. By analyzing the overlap of genes enriched in the IP/Input of MCH neuron activated mice with previously identified cell types using single cell mRNA sequencing of cells in the mediobasal hypothalamus (Campbell et al., 2017), we identified gene clusters which were activated upon MCH neuron activation.
Project description:The postnatal neurodevelopmental disorder Rett syndrome (RTT) is caused by mutations in the gene encoding Methyl-CpG-binding Protein 2 (MeCP2). Despite decades of research, it remains unclear how MeCP2 actually regulates transcription or why RTT features appear only 6-18 months after birth. We examined MeCP2 binding to methylated cytosine in the CH context (mCH, where H = A, C, or T) in the adult mouse brain and found that MeCP2 binds these mCH sites, influencing nucleosome positioning and transcription. Strikingly, this pattern is unique to the mature nervous system, as it requires the increase in mCH after birth to reveal differences in MeCP2 binding to mCG, mCH, and non-methylated DNA elements. This study provides insight into the molecular mechanism governing MeCP2 targeting and how this targeting might contribute to the delayed onset of RTT symptoms. mRNA-Seq were conducted from 7-week-old hypothalamus from MeCP2 knockout mice and their age and genetic background matched wild types control mice. Additonal mRNA-Seq were conducted from 7-week-old hypothalamus from MeCP2 transgenic mice and their age and genetic background matched wild types control mice.
Project description:The postnatal neurodevelopmental disorder Rett syndrome (RTT) is caused by mutations in the gene encoding Methyl-CpG-binding Protein 2 (MeCP2). Despite decades of research, it remains unclear how MeCP2 actually regulates transcription or why RTT features appear only 6-18 months after birth. We examined MeCP2 binding to methylated cytosine in the CH context (mCH, where H = A, C, or T) in the adult mouse brain and found that MeCP2 binds these mCH sites, influencing nucleosome positioning and transcription. Strikingly, this pattern is unique to the mature nervous system, as it requires the increase in mCH after birth to reveal differences in MeCP2 binding to mCG, mCH, and non-methylated DNA elements. This study provides insight into the molecular mechanism governing MeCP2 targeting and how this targeting might contribute to the delayed onset of RTT symptoms. MeCP2 ChIP-Seq were conducted from ~ 7-week-old hypothalamus tissues from Mecp2-/y; MECP2-EGFP mice.
Project description:The postnatal neurodevelopmental disorder Rett syndrome (RTT) is caused by mutations in the gene encoding Methyl-CpG-binding Protein 2 (MeCP2). Despite decades of research, it remains unclear how MeCP2 actually regulates transcription or why RTT features appear only 6-18 months after birth. We examined MeCP2 binding to methylated cytosine in the CH context (mCH, where H = A, C, or T) in the adult mouse brain and found that MeCP2 binds these mCH sites, influencing nucleosome positioning and transcription. Strikingly, this pattern is unique to the mature nervous system, as it requires the increase in mCH after birth to reveal differences in MeCP2 binding to mCG, mCH, and non-methylated DNA elements. This study provides insight into the molecular mechanism governing MeCP2 targeting and how this targeting might contribute to the delayed onset of RTT symptoms. Mnase-Seq were conducted from 7-week-old hypothalamus from MeCP2 knockout mice and their age and genetic background matched wild types control mice.
Project description:Hypothalamic hypocretin (HCRT) and melanin concentrating hormone (MCH) have multiple functions including sleep and metabolism. How these neuropeptides are produced and involved in divers functions remain unknown. We developed methods to sort and purify HCRT and MCH neurons from mouse hypothalamus. RNA-sequencing revealed key factors of fate determination for HCRT (Peg3, Ahr1, Six6, Nr2f2 and Prrx1) and MCH (Lmx1, Gbx2 and Peg3) neurons. Amongst these, loss of Peg3 in mice significantly reduces HCRT and MCH cell numbers while knock-down of Peg3 ortholog in zebrafish completely abolishes their expression resulting in a two fold increase in sleep. The transcriptome results were used to produce HCRT and MCH neurons from induced pluripotent stem cells (iPSCs) and ascorbic acid was found necessary for HCRT and BMP7 for MCH cell differentiation. Our results provide a platform to understand the development and expression of HCRT and MCH and their multiple functions in health and disease.
Project description:In Alzheimer’s disease (AD), pathophysiological changes in the hippocampus cause deficits in episodic memory formation, leading to cognitive impairment. Hippocampal hyperactivity and decreased sleep quality are associated with early AD, but their basis is poorly understood. We find that homeostatic mechanisms transiently counteract increased excitatory drive of hippocampal CA1 neurons in AppNL-G-F mice, but fail to stabilize it at control levels. Spatial transcriptomics (ST) analysis identifies the Pmch gene encoding Melanin-Concentrating Hormone (MCH) as part of the adaptive response in AppNL-G-F mice. Hypothalamic MCH peptide is produced in sleep-active lateral hypothalamic neurons that project to CA1 and modulate memory. We show that MCH downregulates synaptic transmission and modulates firing rate homeostasis in hippocampal neurons. Moreover, MCH reverses the increased excitatory drive of CA1 neurons in AppNL-G-F mice. Consistent with our finding that a reduced fraction of MCH-neurons is active in AppNL-G-F mice, these animals spend less time in rapid eye movement (REM) sleep. In addition, MCH-axons projecting to CA1 become progressively impaired in both AppNL-G-F mice and AD patients. Our findings identify the MCH-system as vulnerable in early AD and suggest that impaired MCH-system function contributes to aberrant excitatory drive and sleep defects, which can compromise hippocampal-dependent functions.
Project description:In order to understand heterogeneity of MCH neurons, by using MCH-Cre dependent ZsGreen (fl/fl) reporter mice, we isolated nuclear from 16 hypothalami of 16 mice at the age of 16-18weeks. Through flow cytometry, we were able to distinguish ZsGreen positive nuclei, and collected puried MCH nuclei in suspension. Those nuclei suspension were subjected to single cell sequence by 10x™ GemCode™ Technology for further single nuleus mRNA analysis and unravel subclusters of MCH neurons