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Ainiwan Y, Chen Y, Mao C, Peng J, Chen S, Wei S, Qi S, Pan J. Adamantinomatous craniopharyngioma cyst fluid can trigger inflammatory activation of microglia to damage the hypothalamic neurons by inducing the production of β-amyloid. J Neuroinflammation 2022; 19:108. [PMID: 35525962 PMCID: PMC9080190 DOI: 10.1186/s12974-022-02470-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 04/27/2022] [Indexed: 12/20/2022] Open
Abstract
INTRODUCTION The mechanism by which adamantinomatous craniopharyngioma (ACP) damages the hypothalamus is still unclear. Cyst fluid rich in lipids and inflammatory factors is a characteristic pathological manifestation of ACP and may play a very important role in hypothalamic injury caused by tumors. OBJECTIVE The objective of this study was to construct a reliable animal model of ACP cyst fluid-induced hypothalamic injury and explore the specific mechanism of hypothalamic injury caused by cyst fluid. METHODS An animal model was established by injecting human ACP cyst fluid into the bilateral hypothalamus of mice. ScRNA-seq was performed on the mice hypothalamus and on an ACP sample to obtain a complete gene expression profile for analysis. Data verification was performed through pathological means. RESULTS ACP cystic fluid caused growth retardation and an increased obesity index in mice, affected the expression of the Npy, Fgfr2, Rnpc3, Sst, and Pcsk1n genes that regulate growth and energy metabolism in hypothalamic neurons, and enhanced the cellular interaction of Agrp-Mc3r. ACP cystic fluid significantly caused inflammatory activation of hypothalamic microglia. The cellular interaction of CD74-APP is significantly strengthened between inflammatory activated microglia and hypothalamic neurons. Beta-amyloid, a marker of neurodegenerative diseases, was deposited in the ACP tumor tissues and in the hypothalamus of mice injected with ACP cyst fluid. CONCLUSION In this study, a novel animal model of ACP cystic fluid-hypothalamic injury was established. For the first time, it was found that ACP cystic fluid can trigger inflammatory activation of microglia to damage the hypothalamus, which may be related to the upregulation of the CD74-APP interaction and deposition of β-amyloid, implying that there may be a similar mechanism between ACP cystic fluid damage to the hypothalamus and neurodegenerative diseases.
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Affiliation(s)
- Yilamujiang Ainiwan
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, No. 1838, Guangzhou North Road, Guangzhou, Guangdong, China
| | - Yiguang Chen
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, No. 1838, Guangzhou North Road, Guangzhou, Guangdong, China
| | - Chaofu Mao
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, No. 1838, Guangzhou North Road, Guangzhou, Guangdong, China
| | - Junxiang Peng
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, No. 1838, Guangzhou North Road, Guangzhou, Guangdong, China
| | - Siyuan Chen
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, No. 1838, Guangzhou North Road, Guangzhou, Guangdong, China
| | - Songtao Wei
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, No. 1838, Guangzhou North Road, Guangzhou, Guangdong, China
| | - Songtao Qi
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, No. 1838, Guangzhou North Road, Guangzhou, Guangdong, China.
| | - Jun Pan
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, No. 1838, Guangzhou North Road, Guangzhou, Guangdong, China.
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Alshafie W, Francis V, Bednarz K, Pan YE, Stroh T, McPherson PS. Regulated resurfacing of a somatostatin receptor storage compartment fine-tunes pituitary secretion. J Cell Biol 2020; 219:132745. [PMID: 31825461 PMCID: PMC7039187 DOI: 10.1083/jcb.201904054] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/26/2019] [Accepted: 10/25/2019] [Indexed: 12/15/2022] Open
Abstract
In pituitary cells, internalized somatostatin receptor is held in a GLUT4-like storage compartment. The receptor rapidly resurfaces in response to selective signaling pathways in a process that fine-tunes pituitary hormone release. The surfacing of the glucose transporter GLUT4 driven by insulin receptor activation provides the prototypic example of a homeostasis response dependent on mobilization of an intracellular storage compartment. Here, we generalize this concept to a G protein–coupled receptor, somatostatin receptor subtype 2 (SSTR2), in pituitary cells. Following internalization in corticotropes, SSTR2 moves to a juxtanuclear syntaxin-6–positive compartment, where it remains until the corticotropes are stimulated with corticotropin releasing factor (CRF), whereupon SSTR2 exits the compartment on syntaxin-6–positive vesicular/tubular carriers that depend on Rab10 for their fusion with the plasma membrane. As SSTR2 activation antagonizes CRF-mediated hormone release, this storage/resurfacing mechanism may allow for a physiological homeostatic feedback system. In fact, we find that SSTR2 moves from an intracellular compartment to the cell surface in pituitary gland somatotropes, concomitant with increasing levels of serum growth hormone (GH) during natural GH cycles. Our data thus provide a mechanism by which signaling-mediated plasma membrane resurfacing of SSTR2 can fine-tune pituitary hormone release.
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Affiliation(s)
- Walaa Alshafie
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Vincent Francis
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Klaudia Bednarz
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Yingzhou Edward Pan
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Thomas Stroh
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Peter S McPherson
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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Bednarz K, Alshafie W, Aufmkolk S, Desserteaux T, Markam PS, Storch KF, Stroh T. Ultradian Secretion of Growth Hormone in Mice: Linking Physiology With Changes in Synapse Parameters Using Super-Resolution Microscopy. Front Neural Circuits 2020; 14:21. [PMID: 32523515 PMCID: PMC7261915 DOI: 10.3389/fncir.2020.00021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/14/2020] [Indexed: 01/19/2023] Open
Abstract
Neuroendocrine circuits are orchestrated by the pituitary gland in response to hypothalamic hormone-releasing and inhibiting factors to generate an ultradian and/or circadian rhythm of hormone secretion. However, mechanisms that govern this rhythmicity are not fully understood. It has been shown that synaptic transmission in the rodent hypothalamus undergoes cyclical changes in parallel with rhythmic hormone secretion and a growing body of evidence suggests that rapid rewiring of hypothalamic neurons may be the source of these changes. For decades, structural synaptic studies have been utilizing electron microscopy, which provides the resolution suitable for visualizing synapses. However, the small field of view, limited specificity and manual analysis susceptible to bias fuel the search for a more quantitative approach. Here, we apply the fluorescence super-resolution microscopy approach direct Stochastic Optical Reconstruction Microscopy (dSTORM) to quantify and structurally characterize excitatory and inhibitory synapses that contact growth hormone-releasing-hormone (GHRH) neurons during peak and trough values of growth hormone (GH) concentration in mice. This approach relies on a three-color immunofluorescence staining of GHRH and pre- and post-synaptic markers, and a quantitative analysis with a Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm. With this method we confirm our previous findings, using electron microscopy, of increased excitatory synaptic input to GHRH neurons during peak levels of GH. Additionally, we find a shift in synapse numbers during low GH levels, where more inhibitory synaptic inputs are detected. Lastly, we utilize dSTORM to study novel aspects of synaptic structure. We show that more excitatory (but not inhibitory) pre-synaptic clusters associate with excitatory post-synaptic clusters during peaks of GH secretion and that the numbers of post-synaptic clusters increase during high hormone levels. The results presented here provide an opportunity to highlight dSTORM as a valuable quantitative approach to study synaptic structure in the neuroendocrine circuit. Importantly, our analysis of GH circuitry sheds light on the potential mechanism that drives ultradian changes in synaptic transmission and possibly aids in GH pulse generation in mice.
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Affiliation(s)
- Klaudia Bednarz
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.,Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Walaa Alshafie
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Sarah Aufmkolk
- Department of Genetics, Harvard Medical School, Boston, MA, United States
| | - Théotime Desserteaux
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Pratap Singh Markam
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.,Douglas Mental Health University Institute, Montreal, QC, Canada
| | - Kai-Florian Storch
- Douglas Mental Health University Institute, Montreal, QC, Canada.,Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - Thomas Stroh
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.,Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
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Somatostatin triggers rhythmic electrical firing in hypothalamic GHRH neurons. Sci Rep 2016; 6:24394. [PMID: 27072430 PMCID: PMC4829871 DOI: 10.1038/srep24394] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 03/29/2016] [Indexed: 12/12/2022] Open
Abstract
Hypothalamic growth hormone-releasing hormone (GHRH) neurons orchestrate body growth/maturation and have been implicated in feeding responses and ageing. However, the electrical patterns that dictate GHRH neuron functions have remained elusive. Since the inhibitory neuropeptide somatostatin (SST) is considered to be a primary oscillator of the GH axis, we examined its acute effects on GHRH neurons in brain slices from male and female GHRH-GFP mice. At the cellular level, SST irregularly suppressed GHRH neuron electrical activity, leading to slow oscillations at the population level. This resulted from an initial inhibitory action at the GHRH neuron level via K+ channel activation, followed by a delayed, sst1/sst2 receptor-dependent unbalancing of glutamatergic and GABAergic synaptic inputs. The oscillation patterns induced by SST were sexually dimorphic, and could be explained by differential actions of SST on both GABAergic and glutamatergic currents. Thus, a tripartite neuronal circuit involving a fast hyperpolarization and a dual regulation of synaptic inputs appeared sufficient in pacing the activity of the GHRH neuronal population. These “feed-forward loops” may represent basic building blocks involved in the regulation of GHRH release and its downstream sexual specific functions.
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Musumeci G, Castorina S, Castrogiovanni P, Loreto C, Leonardi R, Aiello FC, Magro G, Imbesi R. A journey through the pituitary gland: Development, structure and function, with emphasis on embryo-foetal and later development. Acta Histochem 2015; 117:355-66. [PMID: 25858531 DOI: 10.1016/j.acthis.2015.02.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 12/28/2014] [Accepted: 02/05/2015] [Indexed: 12/22/2022]
Abstract
The pituitary gland and the hypothalamus are morphologically and functionally associated in the endocrine and neuroendocrine control of other endocrine glands. They therefore play a key role in a number of regulatory feedback processes that co-ordinate the whole endocrine system. Here we review the neuroendocrine system, from the discoveries that led to its identification to some recently clarified embryological, functional, and morphological aspects. In particular we review the pituitary gland and the main notions related to its development, organization, cell differentiation, and vascularization. Given the crucial importance of the factors controlling neuroendocrine system development to understand parvocellular neuron function and the aetiology of the congenital disorders related to hypothalamic-pituitary axis dysfunction, we also provide an overview of the molecular and genetic studies that have advanced our knowledge in the field. Through the action of the hypothalamus, the pituitary gland is involved in the control of a broad range of key aspects of our lives: the review focuses on the hypothalamic-pituitary-gonadal axis, particularly GnRH, whose abnormal secretion is associated with clinical conditions involving delayed or absent puberty and reproductive dysfunction.
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6
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Wang X, Yang L, Wang H, Shao F, Yu J, Jiang H, Han Y, Gong D, Gu Z. Growth hormone-regulated mRNAs and miRNAs in chicken hepatocytes. PLoS One 2014; 9:e112896. [PMID: 25386791 PMCID: PMC4227886 DOI: 10.1371/journal.pone.0112896] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 10/16/2014] [Indexed: 12/02/2022] Open
Abstract
Growth hormone (GH) is a key regulatory factor in animal growth, development and metabolism. Based on the expression level of the GH receptor, the chicken liver is a major target organ of GH, but the biological effects of GH on the chicken liver are not fully understood. In this work we identified mRNAs and miRNAs that are regulated by GH in primary hepatocytes from female chickens through RNA-seq, and analyzed the functional relevance of these mRNAs and miRNAs through GO enrichment analysis and miRNA target prediction. A total of 164 mRNAs were found to be differentially expressed between GH-treated and control chicken hepatocytes, of which 112 were up-regulated and 52 were down-regulated by GH. A total of 225 chicken miRNAs were identified by the RNA-Seq analysis. Among these miRNAs 16 were up-regulated and 1 miRNA was down-regulated by GH. The GH-regulated mRNAs were mainly involved in growth and metabolism. Most of the GH-upregulated or GH-downregulated miRNAs were predicted to target the GH-downregulated or GH-upregulated mRNAs, respectively, involved in lipid metabolism. This study reveals that GH regulates the expression of many mRNAs involved in metabolism in female chicken hepatocytes, which suggests that GH plays an important role in regulating liver metabolism in female chickens. The results of this study also support the hypothesis that GH regulates lipid metabolism in chicken liver in part by regulating the expression of miRNAs that target the mRNAs involved in lipid metabolism.
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Affiliation(s)
- Xingguo Wang
- Department of Life Science and Technology, Changshu Institute of Technology, Changshu, P R China
- College of Animal Science and Technology, Yangzhou University, Yangzhou, P R China
| | - Lei Yang
- Department of Life Science and Technology, Changshu Institute of Technology, Changshu, P R China
| | - Huijuan Wang
- Department of Life Science and Technology, Changshu Institute of Technology, Changshu, P R China
| | - Fang Shao
- Department of Life Science and Technology, Changshu Institute of Technology, Changshu, P R China
| | - JianFeng Yu
- Department of Life Science and Technology, Changshu Institute of Technology, Changshu, P R China
| | - Honglin Jiang
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Yaoping Han
- Department of Life Science and Technology, Changshu Institute of Technology, Changshu, P R China
| | - Daoqing Gong
- College of Animal Science and Technology, Yangzhou University, Yangzhou, P R China
| | - Zhiliang Gu
- Department of Life Science and Technology, Changshu Institute of Technology, Changshu, P R China
- * E-mail:
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7
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Toossi H, Del Cid-Pellitero E, Stroh T, Jones BE. Somatostatin varicosities contain the vesicular GABA transporter and contact orexin neurons in the hypothalamus. Eur J Neurosci 2012; 36:3388-95. [PMID: 22925106 DOI: 10.1111/j.1460-9568.2012.08253.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Somatostatin (SST) is a neuropeptide with known inhibitory actions in the hypothalamus, where it inhibits release of growth hormone-releasing hormone (GHRH), while also influencing the sleep-wake cycle. Here we investigated in the rat whether SST neurons might additionally release GABA (gamma-aminobutyric acid) or glutamate in different regions and whether they might contact orexin neurons that play an important role in the maintenance of wakefulness. In dual-immunostained sections viewed by epifluorescence microscopy, we examined if SST varicosities were immunopositive for the vesicular transporter for GABA (VGAT) or glutamate (VGLUT2) in the posterolateral hypothalamus and neighboring arcuate nucleus and median eminence. Of the SST varicosities in the posterolateral hypothalamus, 18% were immunopositive for VGAT, whereas ≤ 1% were immunopositive for VGLUT2. In the arcuate and median eminence, 26 and 64% were VGAT+ and < 3% VGLUT2 + , respectively. In triple-immunostained sections viewed by epifluorescence and confocal microscopy, SST varicosities were seen in contact with orexin somata, and of these varicosities, a significant proportion (23%) contained VGAT along with synaptophysin, the presynaptic marker for small synaptic vesicles, and a similar proportion (25%) abutted puncta that were immunostained for gephyrin, the postsynaptic marker for GABAergic synapses. Our results indicate that a significant proportion of SST varicosities in the hypothalamus have the capacity to release GABA, to form inhibitory synapses upon orexin neurons, and accordingly through their peptide and/or amino acid, to inhibit orexin neurons, as well as GHRH neurons. Thus while regulating GHRH release, SST neurons could serve to attenuate arousal and permit progression through the sleep cycle.
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Affiliation(s)
- Hanieh Toossi
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada H3A 2B4
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8
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Shpakov AO, Shpakova EA. [Development of non-hormonal regulators of adenylyl cyclase signaling system on the basis of peptides, derivatives of the third intracellular loop of somatostatin receptors]. BIOMEDITSINSKAIA KHIMIIA 2012; 58:446-456. [PMID: 23413689 DOI: 10.18097/pbmc20125804446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In the majority of the serpentine type receptors the third intracellular loop (ICL-3) is responsible for interaction with heterotrimeric G-proteins and for transduction of hormonal signal to the enzymes, generators of the second messengers. It was found that the peptides corresponding to ICL-3 influence functional activity of hormonal signaling systems in the absence of the hormone and, in consequence, can be considered as prototypes for the development of selective regulators of these systems. We have originally synthesized peptides corresponding to C-terminal regions 255-269 and 240 254 of ICL-3 of type 1 and 2 rat somatostatin receptors (Som1R and Som2R). Micromolar concentrations of these peptides activated Gi-proteins and inhibited forskolin-stimulated activity of adenylyl cyclase (AC) in rat brain tissues. The peptide 255-269 of Som1R is a selective antagonist of Som1R, and the peptide 240-254 of Som2R is an agonist of Som1R. So, the peptide 255-269 of Som1R decreased the regulatory effects of somatostatin and selective Som1R-agonist CH-275 realized via the receptor homologous to them, while the peptide 240-254 of Som2R, on the contrary, increased AC inhibitory action of CH-275. Both peptides insignificantly influenced regulatory effects of the Som2R-agonist octreotide. Summing up, the peptides studied by us are selective regulators of somatostatin-sensitive AC system. Using the peptides it was shown that ICL-3 of Som1R and Som2R includes the main molecular determinants that are responsible for activation of Gi-proteins and regulation of AC system by somatostatin and its analogues.
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Gene expression changes in the septum: possible implications for microRNAs in sculpting the maternal brain. PLoS One 2012; 7:e38602. [PMID: 22701680 PMCID: PMC3368935 DOI: 10.1371/journal.pone.0038602] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 05/12/2012] [Indexed: 01/08/2023] Open
Abstract
The transition from the non-maternal to the maternal state is characterized by a variety of CNS alterations that support the care of offspring. The septum (including lateral and medial portions) is a brain region previously linked to various emotional and motivational processes, including maternal care. In this study, we used microarrays (PLIER algorithm) to examine gene expression changes in the septum of postpartum mice and employed gene set enrichment analysis (GSEA) to identify possible regulators of altered gene expression. Genes of interest identified as differentially regulated with microarray analysis were validated with quantitative real-time PCR. We found that fatty acid binding protein 7 (Fabp7) and galanin (Gal) were downregulated, whereas insulin-like growth factor binding protein 3 (Igfbp3) was upregulated in postpartum mice compared to virgin females. These genes were previously found to be differentially regulated in other brain regions during lactation. We also identified altered expression of novel genes not previously linked to maternal behavior, but that could play a role in postpartum processes, including glutamate-ammonia ligase (Glul) and somatostatin receptor 1 (Sstr1) (both upregulated in postpartum). Genes implicated in metabolism, cell differentiation, or proliferation also exhibited altered expression. Unexpectedly, enrichment analysis revealed a high number of microRNAs, transcription factors, or conserved binding sites (177 with corrected P-value <0.05) that were significantly linked to maternal upregulated genes, while none were linked to downregulated genes. MicroRNAs have been linked to placenta and mammary gland development, but this is the first indication they may also play a key role in sculpting the maternal brain. Together, this study provides new insights into genes (along with possible mechanisms for their regulation) that are involved in septum-mediated adaptations during the postpartum period.
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Abstract
The neuropeptide somatostatin (SRIF) is an important modulator of neurotransmission in the central nervous system and acts as a potent inhibitor of hormone and exocrine secretion. In addition, SRIF regulates cell proliferation in normal and tumorous tissues. The six somatostatin receptor subtypes (sst1, sst2A, sst2B, sst3, sst4, and sst5), which belong to the G protein-coupled receptor (GPCR) family, share a common molecular topology: a hydrophobic core of seven transmembrane-spanning α-helices, three intracellular loops, three extracellular loops, an amino-terminus outside the cell, and a carboxyl-terminus inside the cell. For most of the GPCRs, intracytosolic sequences, and more particularly the C-terminus, are believed to interact with proteins that are mandatory for either exporting neosynthesized receptor, anchoring receptor at the plasma membrane, internalization, recycling, or degradation after ligand binding. Accordingly, most of the SRIF receptors can traffic not only in vitro within different cell types but also in vivo. A picture of the pathways and proteins involved in these processes is beginning to emerge.
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Affiliation(s)
- Zsolt Csaba
- INSERM, Unité Mixte de Recherche U676, Paris, France
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11
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Anderson LL, Scanes CG. Nanobiology and physiology of growth hormone secretion. Exp Biol Med (Maywood) 2012; 237:126-42. [DOI: 10.1258/ebm.2011.011306] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Growth hormone (GH) secretion is controlled by hypothalamic releasing hormones from the median eminence together with hormones and neuropeptides produced by peripheral organs. Secretion of GH involves movement of secretory vesicles along microtubules, transient ‘docking’ with the porosome in the cell membrane and subsequent release of GH. Release of GH is stimulated by GH releasing hormone (GHRH) and inhibited by somatostatin (SRIF). Ghrelin may be functioning to stimulate GH release from somatotropes acting via the GH secretagogue (GHS) receptor (GHSR). However, recent physiological studies militate against this. In addition, ghrelin does influence GH release acting within the hypothalamus. Release of GH from the somatotropes involves the GH-containing secretory granules moving close to the cell surface followed by transitory fusion of the secretory granules with the porosomes located in multiple secretory pits in the cell membrane. Other peptides/proteins can influence GH secretion, particularly in species of non-mammalian vertebrates.
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Affiliation(s)
- Lloyd L Anderson
- Department of Animal Science
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011
| | - Colin G Scanes
- Department of Biological Sciences, University of Wisconsin, Milwaukee, WI 53211, USA
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Girardet C, Bosler O. [Structural plasticity of the adult central nervous system: insights from the neuroendocrine hypothalamus]. Biol Aujourdhui 2011; 205:179-97. [PMID: 21982406 DOI: 10.1051/jbio/2011018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Indexed: 01/26/2023]
Abstract
Accumulating evidence renders the dogma obsolete according to which the structural organization of the brain would remain essentially stable in adulthood, changing only in response to a need for compensatory processes during increasing age and degeneration. It has indeed become clear from investigations on various models that the adult nervous system can adapt to physiological demands by altering reversibly its synaptic circuits. This potential for structural and functional modifications results not only from the plastic properties of neurons but also from the inherent capacity of the glial cellular components to undergo remodeling as well. This is currently known for astrocytes, the major glial cells in brain which are well-recognized as dynamic partners in the mechanisms of synaptic transmission, and for the tanycytes and pituicytes which contribute to the regulation of neurosecretory processes in neurohemal regions of the hypothalamus. Studies on the neuroendocrine hypothalamus, whose role is central in homeostatic regulations, have gained good insights into the spectacular neuronal-glial rearrangements that may subserve functional plasticity in the adult brain. Following pioneering works on the morphological reorganizations taking place in the hypothalamo-neurohypophyseal system under certain physiological conditions such as dehydration and lactation, studies on the gonadotropic system that orchestrates reproductive functions have re-emphasized the dynamic interplay between neurons and glia in brain structural plasticity processes. This review summarizes the major contributions provided by these researches in the field and also addresses the question of the morphological rearrangements that occur on a 24-h basis in the central component of the circadian clock responsible for the temporal aspects of endocrine regulations. Taken together, the reviewed data highlight the close cooperation between neurons and glia in developing strategies for functional adaptation of the brain to the changing conditions of the internal and external environment.
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Affiliation(s)
- Clémence Girardet
- Centre de Recherche en Neurobiologie-Neurophysiologie de Marseille, France.
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Shpakov AO, Shpakova EA. Development of non-hormonal regulators of the adenylyl cyclase signaling system based on the peptides, derivatives of the third intracellular loop of somatostatin receptors. BIOCHEMISTRY (MOSCOW) SUPPLEMENT SERIES B: BIOMEDICAL CHEMISTRY 2011. [DOI: 10.1134/s1990750811030127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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14
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Shpakova EA, Shpakov AO. Peptides corresponding to intracellular regions of somatostatin receptors with agonist and antagonist activity. DOKL BIOCHEM BIOPHYS 2011; 437:68-71. [PMID: 21590378 DOI: 10.1134/s1607672911020049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Indexed: 11/23/2022]
Affiliation(s)
- E A Shpakova
- Institute of High-Molecular-Weight Compounds, Russian Academy of Sciences St. Petersburg, 199004, Russia
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Girardet C, Becquet D, Blanchard MP, François-Bellan AM, Bosler O. Neuroglial and synaptic rearrangements associated with photic entrainment of the circadian clock in the suprachiasmatic nucleus. Eur J Neurosci 2010; 32:2133-42. [DOI: 10.1111/j.1460-9568.2010.07520.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Goebel M, Stengel A, Wang L, Coskun T, Alsina-Fernandez J, Rivier J, Taché Y. Pattern of Fos expression in the brain induced by selective activation of somatostatin receptor 2 in rats. Brain Res 2010; 1351:150-164. [PMID: 20637739 DOI: 10.1016/j.brainres.2010.07.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 06/28/2010] [Accepted: 07/08/2010] [Indexed: 02/08/2023]
Abstract
Central activation of somatostatin (sst) receptors by oligosomatostatin analogs inhibits growth hormone and stress-related rise in catecholamine plasma levels while stimulating grooming, feeding behaviors, gastric transit and acid secretion, which can be mimicked by selective sst(2) receptor agonist. To evaluate the pattern of neuronal activation induced by peptide sst receptor agonists, we assessed Fos-expression in rat brain after intracerebroventricular (i.c.v.) injection of a newly developed selective sst(2) agonist compared to the oligosomatostatin ODT8-SST, a pan-sst(1-5) agonist. Ninety min after injection of vehicle (10 microl) or previously established maximal orexigenic dose of peptides (1 microg=1 nmol/rat), brains were assessed for Fos-immunohistochemistry and doublelabeling. Food and water were removed after injection. The sst(2) agonist and ODT8-SST induced a similar Fos distribution pattern except in the arcuate nucleus where only the sst(2) agonist increased Fos. Compared to ODT8-SST, the sst(2) agonist induced higher Fos-expression by 3.7-times in the basolateral amygdaloid nucleus, 1.2-times in the supraoptic nucleus (SON), 1.6-times in the magnocellular paraventricular hypothalamic nucleus (mPVN), 4.1-times in the external lateral parabrachial nucleus, and 2.6-times in both the inferior olivary nucleus and superficial layer of the caudal spinal trigeminal nucleus. Doublelabeling in the hypothalamus showed that ODT8-SST activates 36% of oxytocin, 63% of vasopressin and 79% of sst(2) immunoreactive neurons in the mPVN and 28%, 55% and 25% in the SON, respectively. Selective activation of sst(2) receptor results in a more robust neuronal activation than the pan-sst(1-5) agonist in various brain regions that may have relevance in sst(2) mediated alterations of behavioral, autonomic and endocrine functions.
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Affiliation(s)
- Miriam Goebel
- CURE/Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division, Department of Medicine, David Geffen School of Medicine, UCLA and VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Andreas Stengel
- CURE/Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division, Department of Medicine, David Geffen School of Medicine, UCLA and VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Lixin Wang
- CURE/Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division, Department of Medicine, David Geffen School of Medicine, UCLA and VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Tamer Coskun
- Biotechnology Discovery Research, Eli Lilly and Company, Indianapolis, IN, USA
| | | | - Jean Rivier
- Peptide Biology Laboratories, Salk Institute, La Jolla, CA, USA
| | - Yvette Taché
- CURE/Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division, Department of Medicine, David Geffen School of Medicine, UCLA and VA Greater Los Angeles Healthcare System, Los Angeles, California, USA.
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