1
|
Thornburg-Suresh EJC, Richardson JE, Summers DW. The Stathmin-2 membrane-targeting domain is required for axon protection and regulated degradation by DLK signaling. J Biol Chem 2023; 299:104861. [PMID: 37236359 PMCID: PMC10404615 DOI: 10.1016/j.jbc.2023.104861] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 05/16/2023] [Accepted: 05/19/2023] [Indexed: 05/28/2023] Open
Abstract
Axon integrity is essential for functional connectivity in the nervous system. The degeneration of stressed or damaged axons is a common and sometimes initiating event in neurodegenerative disorders. Stathmin-2 (Stmn2) is an axon maintenance factor that is depleted in amyotrophic lateral sclerosis, and replenishment of Stmn2 can restore neurite outgrowth in diseased neurons. However, mechanisms responsible for Stmn2-mediated axon maintenance in injured neurons are not known. We used primary sensory neurons to interrogate the role of Stmn2 in the degeneration of severed axons. We discover that membrane association of Stmn2 is critical for its axon-protective activity. Structure-function studies revealed that axonal enrichment of Stmn2 is driven by palmitoylation as well as tubulin interaction. Using live imaging, we discover that another Stmn, Stmn3, comigrates with Stmn2-containing vesicles. We also demonstrate that Stmn3 undergoes regulated degradation through dual leucine zipper kinase (DLK)-c-Jun N-terminal kinase signaling. The Stmn2 membrane-targeting domain is both necessary and sufficient for localization to a specific vesicle population and confers sensitivity to DLK-dependent degradation. Our findings reveal a broader role for DLK in tuning the local abundance of palmitoylated Stmns in axon segments. Moreover, palmitoylation is a critical component of Stmn-mediated axon protection, and defining the Stmn2-containing vesicle population will provide important clues toward mechanisms of axon maintenance.
Collapse
Affiliation(s)
- Emma J C Thornburg-Suresh
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa, USA; Department of Biology, University of Iowa, Iowa City, Iowa, USA
| | | | - Daniel W Summers
- Department of Biology, University of Iowa, Iowa City, Iowa, USA; Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA.
| |
Collapse
|
2
|
Asadi F, Fernandez Andrade JA, Gillies R, Lee K, Dhanvantari S, Hardy DB, Arany EJ. Sex-dependent Effect of In-utero Exposure to Δ 9-Tetrahydrocannabinol on Glucagon and Stathmin-2 in Adult Rat Offspring. Can J Diabetes 2022; 46:851-862. [PMID: 35985923 DOI: 10.1016/j.jcjd.2022.06.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 06/15/2022] [Accepted: 06/27/2022] [Indexed: 01/06/2023]
Abstract
OBJECTIVES Administration of Δ9-tetrahydrocannabinol (Δ9-THC) to pregnant rats results in glucose intolerance, insulin resistance and reduced islet mass in female, but not male, offspring. The effects of Δ9-THC on other islet hormones is not known. One downstream target of the cannabinoid receptor, stathmin-2 (Stmn2), has recently been shown to suppress glucagon secretion, thereby suggesting Δ9-THC may also affect alpha-cell function. The aim of the present study was to determine the effects of in-utero Δ9-THC exposure on the profile of glucagon, insulin and Stmn2 in the rat offspring islet and serum. METHODS Pregnant Wistar rat dams were injected with Δ9-THC (3 mg/kg per day, intraperitoneally) or vehicle from gestational day 6 to birth. Offspring were euthanized at postnatal day 21 (PND21) or at 5 months (adult) to collect blood and pancreata. RESULTS At PND21, control and Δ9-THC-exposed offspring showed that Stmn2 had a strong colocalization with glucagon (Pearson's correlation coefficient ≥0.6), and a weak colocalization with insulin (Pearson's correlation coefficient <0.4) in both males and females, with no changes by either treatment or sex. In adult female offspring in the Δ9-THC group, intensity analysis indicated an increased insulin-to-glucagon (I/G; p<0.05) ratio and a decreased glucagon-to-Stmn2 (G/S; p<0.01) ratio, and no changes in these ratios in adult males. Furthermore, Δ9-THC did not alter fasting blood glucose and serum insulin levels in either male or female adult offspring. However, female Δ9-THC-exposed offspring exhibited an increased I/G ratio (p<0.05) and decreased G/S ratio in serum by adulthood (p<0.05). CONCLUSION Collectively, the reduced G/S ratio in both islet and serum in association with an increased serum I/G ratio has direct correlations with early glucose intolerance and insulin resistance observed exclusively in females' offspring in this prenatal cannabinoid model.
Collapse
Affiliation(s)
- Farzad Asadi
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada
| | - Juan Andres Fernandez Andrade
- Lawson Health Research Institute, London, Ontario, Canada; Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Ryan Gillies
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada
| | - Kendrick Lee
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Obstetrics and Gynecology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Savita Dhanvantari
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada; Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Daniel Barry Hardy
- Lawson Health Research Institute, London, Ontario, Canada; Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Obstetrics and Gynecology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Edith Juliana Arany
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada.
| |
Collapse
|
3
|
Asadi F, Dhanvantari S. Stathmin-2 Mediates Glucagon Secretion From Pancreatic α-Cells. Front Endocrinol (Lausanne) 2020; 11:29. [PMID: 32117057 PMCID: PMC7011091 DOI: 10.3389/fendo.2020.00029] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 01/14/2020] [Indexed: 01/26/2023] Open
Abstract
Inhibition of glucagon hypersecretion from pancreatic α-cells is an appealing strategy for the treatment of diabetes. Our hypothesis is that proteins that associate with glucagon within alpha cell secretory granules will regulate glucagon secretion, and may provide druggable targets for controlling abnormal glucagon secretion in diabetes. Recently, we identified a dynamic glucagon interactome within the secretory granules of the α cell line, αTC1-6, and showed that select proteins within the interactome could modulate glucagon secretion. In the present study, we show that one of these interactome proteins, the neuronal protein stathmin-2, is expressed in αTC1-6 cells and in mouse pancreatic alpha cells, and is a novel regulator of glucagon secretion. The secretion of both glucagon and Stmn2 was significantly enhanced in response to 55 mM K+, and immunofluorescence confocal microscopy showed co-localization of stathmin-2 with glucagon and the secretory granule markers chromogranin A and VAMP-2 in αTC1-6 cells. In mouse pancreatic islets, Stathmin-2 co-localized with glucagon, but not with insulin, and co-localized with secretory pathway markers. To show a function for stathmin-2 in regulating glucagon secretion, we showed that siRNA-mediated depletion of stathmin-2 in αTC1-6 cells caused glucagon secretion to become constitutive without any effect on proglucagon mRNA levels, while overexpression of stathmin-2 completely abolished both basal and K+-stimulated glucagon secretion. Overexpression of stathmin-2 increased the localization of glucagon into the endosomal-lysosomal compartment, while depletion of stathmin-2 reduced the endosomal localization of glucagon. Therefore, we describe stathmin-2 as having a novel role as an alpha cell secretory granule protein that modulates glucagon secretion via trafficking through the endosomal-lysosomal system. These findings describe a potential new pathway for the regulation of glucagon secretion, and may have implications for controlling glucagon hypersecretion in diabetes.
Collapse
Affiliation(s)
- Farzad Asadi
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - Savita Dhanvantari
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
- Department of Medical Biophysics, Western University, London, ON, Canada
- Lawson Health Research Institute, London, ON, Canada
- *Correspondence: Savita Dhanvantari
| |
Collapse
|
4
|
Ito T, Matsubara D, Tanaka I, Makiya K, Tanei ZI, Kumagai Y, Shiu SJ, Nakaoka HJ, Ishikawa S, Isagawa T, Morikawa T, Shinozaki-Ushiku A, Goto Y, Nakano T, Tsuchiya T, Tsubochi H, Komura D, Aburatani H, Dobashi Y, Nakajima J, Endo S, Fukayama M, Sekido Y, Niki T, Murakami Y. Loss of YAP1 defines neuroendocrine differentiation of lung tumors. Cancer Sci 2016; 107:1527-1538. [PMID: 27418196 PMCID: PMC5084673 DOI: 10.1111/cas.13013] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/21/2016] [Accepted: 07/12/2016] [Indexed: 01/24/2023] Open
Abstract
YAP1, the main Hippo pathway effector, is a potent oncogene and is overexpressed in non‐small‐cell lung cancer (NSCLC); however, the YAP1 expression pattern in small‐cell lung cancer (SCLC) has not yet been elucidated in detail. We report that the loss of YAP1 is a special feature of high‐grade neuroendocrine lung tumors. A hierarchical cluster analysis of 15 high‐grade neuroendocrine tumor cell lines containing 14 SCLC cell lines that depended on the genes of Hippo pathway molecules and neuroendocrine markers clearly classified these lines into two groups: the YAP1‐negative and neuroendocrine marker‐positive group (n = 11), and the YAP1‐positive and neuroendocrine marker‐negative group (n = 4). Among the 41 NSCLC cell lines examined, the loss of YAP1 was only observed in one cell line showing the strong expression of neuroendocrine markers. Immunostaining for YAP1, using the sections of 189 NSCLC, 41 SCLC, and 30 large cell neuroendocrine carcinoma (LCNEC) cases, revealed that the loss of YAP1 was common in SCLC (40/41, 98%) and LCNEC (18/30, 60%), but was rare in NSCLC (6/189, 3%). Among the SCLC and LCNEC cases tested, the loss of YAP1 correlated with the expression of neuroendocrine markers, and a survival analysis revealed that YAP1‐negative cases were more chemosensitive than YAP1‐positive cases. Chemosensitivity test for cisplatin using YAP1‐positive/YAP1‐negative SCLC cell lines also showed compatible results. YAP1‐sh‐mediated knockdown induced the neuroendocrine marker RAB3a, which suggested the possible involvement of YAP1 in the regulation of neuroendocrine differentiation. Thus, we showed that the loss of YAP1 has potential as a clinical marker for predicting neuroendocrine features and chemosensitivity.
Collapse
Affiliation(s)
- Takeshi Ito
- Molecular Pathology Laboratory, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Daisuke Matsubara
- Molecular Pathology Laboratory, Institute of Medical Science, University of Tokyo, Tokyo, Japan. .,Department of Integrative Pathology, Jichi Medical University, Tochigi, Japan.
| | - Ichidai Tanaka
- Division of Molecular Oncology, Aichi Cancer Center Research Institute, Aichi, Japan
| | - Kanae Makiya
- Molecular Pathology Laboratory, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Zen-Ichi Tanei
- Molecular Pathology Laboratory, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Yuki Kumagai
- Molecular Pathology Laboratory, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Shu-Jen Shiu
- Molecular Pathology Laboratory, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Hiroki J Nakaoka
- Molecular Pathology Laboratory, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Shumpei Ishikawa
- Department of Genomic Pathology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takayuki Isagawa
- Department of Genomic Pathology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Teppei Morikawa
- Department of Human Pathology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Aya Shinozaki-Ushiku
- Department of Human Pathology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Yasushi Goto
- Department of Respiratory Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Tomoyuki Nakano
- Department of Thoracic Surgery, Jichi Medical University, Tochigi, Japan
| | | | - Hiroyoshi Tsubochi
- Department of Thoracic Surgery, Jichi Medical University Saitama Medical Center, Saitama, Japan
| | - Daisuke Komura
- Division of Genome Science, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, Japan
| | - Hiroyuki Aburatani
- Division of Genome Science, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, Japan
| | - Yoh Dobashi
- Department of Pathology, Jichi Medical University Saitama Medical Center, Saitama, Japan
| | - Jun Nakajima
- Department of Thoracic Surgery, University of Tokyo, Tokyo, Japan
| | - Shunsuke Endo
- Department of Thoracic Surgery, Jichi Medical University, Tochigi, Japan
| | - Masashi Fukayama
- Department of Human Pathology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Yoshitaka Sekido
- Division of Molecular Oncology, Aichi Cancer Center Research Institute, Aichi, Japan
| | - Toshiro Niki
- Department of Integrative Pathology, Jichi Medical University, Tochigi, Japan
| | - Yoshinori Murakami
- Molecular Pathology Laboratory, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| |
Collapse
|
5
|
Zhang Y, Ni S, Huang B, Wang L, Zhang X, Li X, Wang H, Liu S, Hao A, Li X. Overexpression of SCLIP promotes growth and motility in glioblastoma cells. Cancer Biol Ther 2015; 16:97-105. [PMID: 25511414 DOI: 10.4161/15384047.2014.987037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
SCLIP, a microtubule-destabilizing phosphoprotein, is known to be involved in the development of the central nervous system (CNS). It has been well established that there are notable parallels between normal development and tumorigenesis, especially in glioma. However, no studies have examined the significance of SCLIP in gliomagenesis. To address this, we investigated the expression of SCLIP and its roles in the development of gliomas. Notably, we found that SCLIP was highly expressed in various grades of glioma samples, as compared with normal brain tissues. Overexpression of SCLIP dramatically stimulated tumor cell migration and invasion as well as proliferation and downregulation of SCLIP showed opposite effects, establishing an important oncogenic role for this gene. Furthermore, we revealed that STAT3 was required to maintain SCLIP stability, suggesting that overexpression of STAT3 may be a critical step to facilitate microtubule dynamics and subsequently promotes migration and invasion of glioma cells. Taken together, our findings demonstrate that SCLIP plays an important role in glioma pathology, and may represent a novel therapeutic strategy against human glioma.
Collapse
Key Words
- BrdU, Bromodeoxyuridine
- CHX, cycloheximide
- ELISA, enzyme-linked immunosorbent assay
- GBM, glioblastoma
- HRP, horseradish peroxidase
- IHC, immunohistochemical
- MTT, 3-[4,5-dimethylthiazol-2-yl] -2,5-diphenyl-tetrazolium bromide
- RT-PCR, reversed transcription polymerase chain reaction
- SCLIP
- SCLIP, SCG10 (superior cervical ganglia protein 10)-like protein Op18, Oncoprotein 18
- STAT3
- WHO, World Health Organization
- glioma
- growth
- motility
- progression
- tumorigenesis
Collapse
Affiliation(s)
- Yanmin Zhang
- a Key Laboratory of the Ministry of Education for Experimental Teratology; Department of Histology and Embryology ; Shandong University School of Medicine ; Jinan , China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Chauvin S, Sobel A. Neuronal stathmins: A family of phosphoproteins cooperating for neuronal development, plasticity and regeneration. Prog Neurobiol 2015; 126:1-18. [DOI: 10.1016/j.pneurobio.2014.09.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 09/23/2014] [Accepted: 09/29/2014] [Indexed: 02/06/2023]
|
7
|
Ratié L, Ware M, Jagline H, David V, Dupé V. Dynamic expression of Notch-dependent neurogenic markers in the chick embryonic nervous system. Front Neuroanat 2014; 8:158. [PMID: 25565981 PMCID: PMC4270182 DOI: 10.3389/fnana.2014.00158] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 12/04/2014] [Indexed: 11/13/2022] Open
Abstract
The establishment of a functional nervous system requires a highly orchestrated process of neural proliferation and differentiation. The evolutionary conserved Notch signaling pathway is a key regulator of this process, regulating basic helix-loop-helix (bHLH) transcriptional repressors and proneural genes. However, little is known about downstream Notch targets and subsequently genes required for neuronal specification. In this report, the expression pattern of Transgelin 3 (Tagln3), Chromogranin A (Chga) and Contactin 2 (Cntn2) was described in detail during early chick embryogenesis. Expression of these genes was largely restricted to the nervous system including the early axon scaffold populations, cranial ganglia and spinal motor neurons. Their temporal and spatial expression were compared with the neuronal markers Nescient Helix-Loop-Helix 1 (Nhlh1), Stathmin 2 (Stmn2) and HuC/D. We show that Tagln3 is an early marker for post-mitotic neurons whereas Chga and Cntn2 are expressed in mature neurons. We demonstrate that inhibition of Notch signaling during spinal cord neurogenesis enhances expression of these markers. This data demonstrates that Tagln3, Chga and Cntn2 represent strong new candidates to contribute to the sequential progression of vertebrate neurogenesis.
Collapse
Affiliation(s)
- Leslie Ratié
- CNRS UMR6290, Faculté de Médecine, Institut de Génétique et Développement de Rennes, Université de Rennes 1 Rennes, France
| | - Michelle Ware
- CNRS UMR6290, Faculté de Médecine, Institut de Génétique et Développement de Rennes, Université de Rennes 1 Rennes, France
| | - Hélène Jagline
- CNRS UMR6290, Faculté de Médecine, Institut de Génétique et Développement de Rennes, Université de Rennes 1 Rennes, France
| | - Véronique David
- CNRS UMR6290, Faculté de Médecine, Institut de Génétique et Développement de Rennes, Université de Rennes 1 Rennes, France ; Laboratoire de Génétique Moléculaire, CHU Pontchaillou Rennes Cedex, France
| | - Valérie Dupé
- CNRS UMR6290, Faculté de Médecine, Institut de Génétique et Développement de Rennes, Université de Rennes 1 Rennes, France
| |
Collapse
|
8
|
Dev NB, Mir SA, Gayen JR, Siddiqui JA, Mustapic M, Vaingankar SM. Cardiac electrical activity in a genomically "humanized" chromogranin a monogenic mouse model with hyperadrenergic hypertension. J Cardiovasc Transl Res 2014; 7:483-493. [PMID: 24821335 DOI: 10.1007/s12265-014-9563-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 04/06/2014] [Indexed: 12/16/2022]
Abstract
The prohormone chromogranin A (CHGA) is ubiquitously found in vesicles of adrenal chromaffin cells and adrenergic neurons, and it is processed to the hypotensive hormone peptide catestatin (CST). Both CHGA and CST regulate blood pressure and cardiac function. This study addresses their role in cardiac electrical activity. We have generated two genomically "humanized" transgenic mouse strains (Tg31CHGA+/+; Chga-/- (HumCHGA31) and Tg19CHGA+/+; Chga-/- (HumCHGA19)) with varied CHGA expression and the ability to rescue the Chga-/- phenotype (hypertensive, hyperadrenergic with dilated cardiomyopathy). The normotensive HumCHGA31 mice express CHGA at levels comparable to wild-type. In contrast, the hypertensive HumCHGA19 mice have low levels of CHGA. EKG recordings revealed that the QT interval, R-amplitude, and QRS time-voltage integral are markedly longer in HumCHGA19 compared to wild-type and HumCHGA31 mice. These differences are accompanied by increased heart rate and QT variability, indicating that ventricular assault happens in a status of low levels of circulating CST.
Collapse
Affiliation(s)
- Nagendu B Dev
- Department of Medicine, University of California at San Diego, USA
| | - Saiful A Mir
- Department of Medicine, University of California at San Diego, USA
| | | | - Jawed A Siddiqui
- Department of Medicine, University of California at San Diego, USA
| | - Maja Mustapic
- Department of Medicine, University of California at San Diego, USA
| | | |
Collapse
|
9
|
Ratié L, Ware M, Barloy-Hubler F, Romé H, Gicquel I, Dubourg C, David V, Dupé V. Novel genes upregulated when NOTCH signalling is disrupted during hypothalamic development. Neural Dev 2013; 8:25. [PMID: 24360028 PMCID: PMC3880542 DOI: 10.1186/1749-8104-8-25] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 12/10/2013] [Indexed: 12/11/2022] Open
Abstract
Background The generation of diverse neuronal types and subtypes from multipotent progenitors during development is crucial for assembling functional neural circuits in the adult central nervous system. It is well known that the Notch signalling pathway through the inhibition of proneural genes is a key regulator of neurogenesis in the vertebrate central nervous system. However, the role of Notch during hypothalamus formation along with its downstream effectors remains poorly defined. Results Here, we have transiently blocked Notch activity in chick embryos and used global gene expression analysis to provide evidence that Notch signalling modulates the generation of neurons in the early developing hypothalamus by lateral inhibition. Most importantly, we have taken advantage of this model to identify novel targets of Notch signalling, such as Tagln3 and Chga, which were expressed in hypothalamic neuronal nuclei. Conclusions These data give essential advances into the early generation of neurons in the hypothalamus. We demonstrate that inhibition of Notch signalling during early development of the hypothalamus enhances expression of several new markers. These genes must be considered as important new targets of the Notch/proneural network.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Valérie Dupé
- Institut de Génétique et Développement de Rennes, CNRS UMR6290, Université de Rennes 1, IFR140 GFAS, Faculté de Médecine, Rennes, France.
| |
Collapse
|
10
|
Wang J, Shan C, Cao W, Zhang C, Teng J, Chen J. SCG10 promotes non-amyloidogenic processing of amyloid precursor protein by facilitating its trafficking to the cell surface. Hum Mol Genet 2013; 22:4888-900. [DOI: 10.1093/hmg/ddt339] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
|
11
|
Abstract
hid-1 was originally identified as a Caenorhabditis elegans gene encoding a novel conserved protein that regulates the decision to enter into the enduring dauer larval stage. We isolated a novel allele of hid-1 in a forward genetic screen for mutants mislocalizing RBF-1 rabphilin, a RAB-27 effector. Here we demonstrate that HID-1 functions in the nervous system to regulate neuromuscular signaling and in the intestine to regulate the defecation motor program. We further show that a conserved N-terminal myristoylated motif of both invertebrate and vertebrate HID-1 is essential for its association with intracellular membranes in nematodes and PC12 cells. C. elegans neuronal HID-1 resides on intracellular membranes in neuronal cell somas; however, the kinesin UNC-104 also transports HID-1 to synaptic regions. HID-1 accumulates in the axons of unc-13 and unc-31 mutants, suggesting it is associated with neurosecretory vesicles. Consistent with this, genetic studies place HID-1 in a peptidergic signaling pathway. Finally, a hid-1 null mutation reduces the levels of endogenous neuropeptides and alters the secretion of fluorescent-tagged cargos derived from neuronal and intestinal dense core vesicles (DCVs). Taken together, our findings indicate that HID-1 is a novel component of a DCV-based neurosecretory pathway and that it regulates one or more aspects of the biogenesis, maturation, or trafficking of DCVs.
Collapse
|
12
|
Courel M, Soler-Jover A, Rodriguez-Flores JL, Mahata SK, Elias S, Montero-Hadjadje M, Anouar Y, Giuly RJ, O'Connor DT, Taupenot L. Pro-hormone secretogranin II regulates dense core secretory granule biogenesis in catecholaminergic cells. J Biol Chem 2010; 285:10030-10043. [PMID: 20061385 PMCID: PMC2843166 DOI: 10.1074/jbc.m109.064196] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 12/16/2009] [Indexed: 11/06/2022] Open
Abstract
Processes underlying the formation of dense core secretory granules (DCGs) of neuroendocrine cells are poorly understood. Here, we present evidence that DCG biogenesis is dependent on the secretory protein secretogranin (Sg) II, a member of the granin family of pro-hormone cargo of DCGs in neuroendocrine cells. Depletion of SgII expression in PC12 cells leads to a decrease in both the number and size of DCGs and impairs DCG trafficking of other regulated hormones. Expression of SgII fusion proteins in a secretory-deficient PC12 variant rescues a regulated secretory pathway. SgII-containing dense core vesicles share morphological and physical properties with bona fide DCGs, are competent for regulated exocytosis, and maintain an acidic luminal pH through the V-type H(+)-translocating ATPase. The granulogenic activity of SgII requires a pH gradient along this secretory pathway. We conclude that SgII is a critical factor for the regulation of DCG biogenesis in neuroendocrine cells, mediating the formation of functional DCGs via its pH-dependent aggregation at the trans-Golgi network.
Collapse
Affiliation(s)
- Maïté Courel
- Department of Medicine, University of California San Diego, La Jolla, California 92093-0838.
| | - Alex Soler-Jover
- Department of Medicine, University of California San Diego, La Jolla, California 92093-0838
| | | | - Sushil K Mahata
- Department of Medicine, University of California San Diego, La Jolla, California 92093-0838; Veteran Affairs San Diego Healthcare System, San Diego, California 92093
| | - Salah Elias
- INSERM U982, University of Rouen, 76821 Mont-St.-Aignan Cedex, France
| | | | - Youssef Anouar
- INSERM U982, University of Rouen, 76821 Mont-St.-Aignan Cedex, France
| | - Richard J Giuly
- National Center for Microscopy and Imaging Research, University of California San Diego, La Jolla, California 92093
| | - Daniel T O'Connor
- Department of Medicine, University of California San Diego, La Jolla, California 92093-0838; Veteran Affairs San Diego Healthcare System, San Diego, California 92093.
| | - Laurent Taupenot
- Department of Medicine, University of California San Diego, La Jolla, California 92093-0838; Veteran Affairs San Diego Healthcare System, San Diego, California 92093.
| |
Collapse
|
13
|
Modlin IM, Gustafsson BI, Moss SF, Pavel M, Tsolakis AV, Kidd M. Chromogranin A--biological function and clinical utility in neuro endocrine tumor disease. Ann Surg Oncol 2010; 17:2427-43. [PMID: 20217257 DOI: 10.1245/s10434-010-1006-3] [Citation(s) in RCA: 244] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Indexed: 02/06/2023]
Abstract
BACKGROUND Neuroendocrine tumors (NETs) are a form of cancer that differ from other neoplasia in that they synthesize, store, and secrete peptides, e.g., chromogranin A (CgA) and amines. A critical issue is late diagnosis due to failure to identify symptoms or to establish the biochemical diagnosis. We review here the utility of CgA measurement in NETs and describe its biological role and the clinical value of its measurement. METHODS Literature review and analysis of the utility of plasma/serum CgA measurements in NETs and other diseases. RESULTS CgA is a member of the chromogranin family; its transcription and peptide processing are well characterized, but its precise function remains unknown. Levels are detectable in the circulation but vary substantially (approximately 25%) depending on which assay is used. Serum and plasma measurements are concordant. CgA is elevated in approximately 90% of gut NETs and correlates with tumor burden and recurrence. Highest values are noted in ileal NETs and gastrointestinal NETs associated with multiple endocrine neoplasia type 1. Both functioning and nonfunctioning pancreatic NETs have elevated values. CgA is more frequently elevated in well-differentiated tumors compared to poorly differentiated NETs. Effective treatment is often associated with decrease in CgA levels. Proton pump inhibitors falsely increase CgA, but levels normalize with therapy cessation. CONCLUSIONS CgA is currently the best available biomarker for the diagnosis of NETs. It is critical to establish diagnosis and has some utility in predicting disease recurrence, outcome, and efficacy of therapy. Measurement of plasma CgA is mandatory for the effective diagnosis and management of NET disease.
Collapse
Affiliation(s)
- Irvin M Modlin
- Gastrointestinal Pathobiology Research Group, Yale University School of Medicine, New Haven, CT, USA.
| | | | | | | | | | | |
Collapse
|
14
|
Sahu BS, Sonawane PJ, Mahapatra NR. Chromogranin A: a novel susceptibility gene for essential hypertension. Cell Mol Life Sci 2010; 67:861-74. [PMID: 19943077 PMCID: PMC11115493 DOI: 10.1007/s00018-009-0208-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 11/06/2009] [Accepted: 11/06/2009] [Indexed: 12/25/2022]
Abstract
Chromogranin A (CHGA) is ubiquitously expressed in secretory cells of the endocrine, neuroendocrine, and neuronal tissues. Although this protein has long been known as a marker for neuroendocrine tumors, its role in cardiovascular disease states including essential hypertension (EH) has only recently been recognized. It acts as a prohormone giving rise to bioactive peptides such as vasostatin-I (human CHGA(1-76)) and catestatin (human CHGA(352-372)) that exhibit several cardiovascular regulatory functions. CHGA is over-expressed but catestatin is diminished in EH. Moreover, genetic variants in the promoter, catestatin, and 3'-untranslated regions of the human CHGA gene alter autonomic activity and blood pressure. Consistent with these findings, targeted ablation of this gene causes severe arterial hypertension and ventricular hypertrophy in mice. Transgenic expression of the human CHGA gene or exogenous administration of catestatin restores blood pressure in these mice. Thus, the accumulated evidence establishes CHGA as a novel susceptibility gene for EH.
Collapse
Affiliation(s)
- Bhavani S. Sahu
- Cardiovascular Genetics Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, 600036 India
| | - Parshuram J. Sonawane
- Cardiovascular Genetics Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, 600036 India
| | - Nitish R. Mahapatra
- Cardiovascular Genetics Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, 600036 India
| |
Collapse
|
15
|
SCG10-like protein (SCLIP) is a STAT3-interacting protein involved in maintaining epithelial morphology in MCF-7 breast cancer cells. Biochem J 2009; 425:95-105. [PMID: 19824884 DOI: 10.1042/bj20091213] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
STAT (signal transducer and activator of transcription) 3 is a key contributor to cancer cell migration and invasion, with excessive STAT3 activity promoting growth arrest, cell-cell dissociation and increased migration of breast cancer epithelial cells. The STAT3-regulated mechanisms involved in this process, however, are not fully defined. Previously, we had revealed SCLIP [SCG10 (superior cervical ganglia protein 10)-like protein] as a novel STAT3-interacting protein. In the present study, we show that STAT3 binds the C-terminal tubulin-associating region of SCLIP. In a search for a function of SCLIP, we show that SCLIP was down-regulated during OSM (oncostatin M) treatment in MCF-7 cells, which also stimulates epithelial morphology loss. SCLIP knockdown likewise triggered a loss of epithelial morphology which included reduced E-cadherin expression. We found that STAT3 was required to maintain SCLIP stability. Furthermore, inhibition of OSM-induced STAT3 activity preserved SCLIP expression and MCF-7 epithelial monolayers. Taken together, we propose that a STAT3-SCLIP interaction is required to preserve SCLIP stability and contributes to the maintenance of normal epithelial morphology. Disruption of the STAT3-SCLIP interaction with OSM may contribute to cytokine-mediated loss in cell-cell attachment and morphology transition in MCF-7 cells.
Collapse
|
16
|
Zhou W, Chen H, Zhang L. The PcG protein hPc2 interacts with the N-terminus of histone demethylase JARID1B and acts as a transcriptional co-repressor. BMB Rep 2009; 42:154-9. [PMID: 19336002 DOI: 10.5483/bmbrep.2009.42.3.154] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
JARID1B (jumonji AT rich interactive domain 1B) is a large nuclear protein that is highly expressed in breast cancers and is proposed to function as a repressor of gene expression. In this paper, a phage display screen using the N-terminus of JARID1B as bait identified one of the JARID1B interacting proteins, namely PcG protein (Polycomb group) hPc2. We demonstrated that the C-terminal region, including the COOH box, was required for the interaction with the N-terminus of JARID1B. In a reporter assay system, co-expression of JARID1B with hPc2 significantly enhanced the transcriptional repression. These results support a role for hPc2 acting as a transcriptional co-repressor.
Collapse
Affiliation(s)
- Wu Zhou
- Institute of Immunology, Zhejiang University, Hangzhou 210058, China
| | | | | |
Collapse
|