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Ruscu M, Capitanescu B, Rupek P, Dandekar T, Radu E, Hermann DM, Popa-Wagner A. The post-stroke young adult brain has limited capacity to re-express the gene expression patterns seen during early postnatal brain development. Brain Pathol 2024; 34:e13232. [PMID: 38198833 PMCID: PMC11328347 DOI: 10.1111/bpa.13232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
The developmental origins of the brain's response to injury can play an important role in recovery after a brain lesion. In this study, we investigated whether the ischemic young adult brain can re-express brain plasticity genes that were active during early postnatal development. Differentially expressed genes in the cortex of juvenile post-natal day 3 and the peri-infarcted cortical areas of young, 3-month-old post-stroke rats were identified using fixed-effects modeling within an empirical Bayes framework through condition-specific comparison. To further analyze potential biological processes, upregulated and downregulated genes were assessed for enrichment using GSEA software. The genes showing the highest expression changes were subsequently verified through RT-PCR. Our findings indicate that the adult brain partially recapitulates the gene expression profile observed in the juvenile brain but fails to upregulate many genes and pathways necessary for brain plasticity. Of the upregulated genes in post-stroke brains, specific roles have not been assigned to Apobec1, Cenpf, Ect2, Folr2, Glipr1, Myo1f, and Pttg1. New genes that failed to upregulate in the adult post-stroke brain include Bex4, Cd24, Klhl1/Mrp2, Trim67, and St8sia2. Among the upregulated pathways, the largest change was observed in the KEGG pathway "One carbon pool of folate," which is necessary for cellular proliferation, followed by the KEGG pathway "Antifolate resistance," whose genes mainly encode the family of ABC transporters responsible for the efflux of drugs that have entered the brain. We also noted three less-described downregulated KEGG pathways in experimental models: glycolipid biosynthesis, oxytocin, and cortisol pathways, which could be relevant as therapeutic targets. The limited brain plasticity of the adult brain is illustrated through molecular and histological analysis of the axonal growth factor, KIF4. Collectively, these results strongly suggest that further research is needed to decipher the complex genetic mechanisms that prevent the re-expression of brain plasticity-associated genes in the adult brain.
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Affiliation(s)
- Mihai Ruscu
- Vascular Neurology and Dementia, Department of Neurology, University Hospital Essen, Essen, Germany
- University of Medicine and Pharmacy Craiova, Craiova, Romania
| | | | - Paul Rupek
- Chair of Bioinformatics, University of Würzburg, Wuerzburg, Germany
| | - Thomas Dandekar
- Chair of Bioinformatics, University of Würzburg, Wuerzburg, Germany
| | - Eugen Radu
- University of Medicine and Pharmacy Carol Davila, Bucharest, Romania
| | - Dirk M Hermann
- Vascular Neurology and Dementia, Department of Neurology, University Hospital Essen, Essen, Germany
- University of Medicine and Pharmacy Craiova, Craiova, Romania
| | - Aurel Popa-Wagner
- Vascular Neurology and Dementia, Department of Neurology, University Hospital Essen, Essen, Germany
- University of Medicine and Pharmacy Craiova, Craiova, Romania
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2
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Holling T, Abdelrazek IM, Elhady GM, Abd Elmaksoud M, Ryu SW, Abdalla E, Kutsche K. A homozygous nonsense variant in the alternatively spliced VLDLR exon 4 causes a neurodevelopmental disorder without features of VLDLR cerebellar hypoplasia. J Hum Genet 2024:10.1038/s10038-024-01279-w. [PMID: 39085459 DOI: 10.1038/s10038-024-01279-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 07/17/2024] [Accepted: 07/20/2024] [Indexed: 08/02/2024]
Abstract
VLDLR cerebellar hypoplasia is characterized by intellectual disability, non-progressive cerebellar ataxia, and seizures. The characteristic MRI findings include hypoplasia of the inferior portion of the cerebellar vermis and hemispheres, simplified cortical gyration, and a small brain stem. Biallelic VLDLR pathogenic variants cause loss-of-function of the encoded very low-density lipoprotein receptor. VLDLR exons 4 and 16 are alternatively spliced, resulting in the expression of four transcript variants, including two exon 4-lacking mRNAs expressed in the human brain. Previously reported VLDLR pathogenic variants affect all four transcript variants. Here we report on two sisters with facial dysmorphism, microcephaly, intellectual disability, and normal brain imaging. Exome sequencing in one patient identified the homozygous VLDLR nonsense variant c.376C>T; p.(Gln126*) in exon 4; her similarly affected sister also carried the homozygous variant and parents were heterozygous carriers. VLDLR transcript analysis identified mRNAs with and without exon 4 in patient fibroblasts, while exon 4-containing VLDLR mRNAs were predominantly detected in control fibroblasts. We found significantly reduced VLDLR mRNA levels in patient compared to control cells, likely caused by nonsense-mediated mRNA decay of exon 4-containing VLDLR transcripts. Expression of neuronal VLDLR isoforms produced from exon 4-lacking transcripts may have protected both patients from developing the cerebellar hypoplasia phenotype.
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Affiliation(s)
- Tess Holling
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ibrahim M Abdelrazek
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Ghada M Elhady
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Marwa Abd Elmaksoud
- Neurology Unit, Pediatric Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | | | - Ebtesam Abdalla
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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Passarella D, Ciampi S, Di Liberto V, Zuccarini M, Ronci M, Medoro A, Foderà E, Frinchi M, Mignogna D, Russo C, Porcile C. Low-Density Lipoprotein Receptor-Related Protein 8 at the Crossroad between Cancer and Neurodegeneration. Int J Mol Sci 2022; 23:ijms23168921. [PMID: 36012187 PMCID: PMC9408729 DOI: 10.3390/ijms23168921] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/07/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022] Open
Abstract
The low-density-lipoprotein receptors represent a family of pleiotropic cell surface receptors involved in lipid homeostasis, cell migration, proliferation and differentiation. The family shares common structural features but also has significant differences mainly due to tissue-specific interactors and to peculiar proteolytic processing. Among the receptors in the family, recent studies place low-density lipoprotein receptor-related protein 8 (LRP8) at the center of both neurodegenerative and cancer-related pathways. From one side, its overexpression has been highlighted in many types of cancer including breast, gastric, prostate, lung and melanoma; from the other side, LRP8 has a potential role in neurodegeneration as apolipoprotein E (ApoE) and reelin receptor, which are, respectively, the major risk factor for developing Alzheimer’s disease (AD) and the main driver of neuronal migration, and as a γ-secretase substrate, the main enzyme responsible for amyloid formation in AD. The present review analyzes the contributions of LDL receptors, specifically of LRP8, in both cancer and neurodegeneration, pointing out that depending on various interactions and peculiar processing, the receptor can contribute to both proliferative and neurodegenerative processes.
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Affiliation(s)
- Daniela Passarella
- Department of Medicine and Health Sciences “V. Tiberio”, University of Molise, 86100 Campobasso, Italy
| | - Silvia Ciampi
- Department of Medicine and Health Sciences “V. Tiberio”, University of Molise, 86100 Campobasso, Italy
| | - Valentina Di Liberto
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, 90133 Palermo, Italy
| | - Mariachiara Zuccarini
- Department of Medical Oral and Biotechnological Sciences, University of Chieti-Pescara, 66100 Chieti, Italy
| | - Maurizio Ronci
- Department of Pharmacy, University of Chieti-Pescara, 66100 Chieti, Italy
| | - Alessandro Medoro
- Department of Medicine and Health Sciences “V. Tiberio”, University of Molise, 86100 Campobasso, Italy
| | - Emanuele Foderà
- Department of Medicine and Health Sciences “V. Tiberio”, University of Molise, 86100 Campobasso, Italy
| | - Monica Frinchi
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, 90133 Palermo, Italy
| | - Donatella Mignogna
- Department of Medicine and Health Sciences “V. Tiberio”, University of Molise, 86100 Campobasso, Italy
| | - Claudio Russo
- Department of Medicine and Health Sciences “V. Tiberio”, University of Molise, 86100 Campobasso, Italy
- Correspondence: ; Tel.: +39-0874404897
| | - Carola Porcile
- Department of Medicine and Health Sciences “V. Tiberio”, University of Molise, 86100 Campobasso, Italy
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Fan J, Yang Y, Qian JK, Zhang X, Ji JQ, Zhang L, Li SZ, Yuan F. Aberrant Expression of PAFAH1B3 Affects Proliferation and Apoptosis in Osteosarcoma. Front Oncol 2021; 11:664478. [PMID: 34136395 PMCID: PMC8201501 DOI: 10.3389/fonc.2021.664478] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/29/2021] [Indexed: 12/16/2022] Open
Abstract
Osteosarcoma is a major malignant tumor of bone and soft tissue, which is presenting with early metastasis and a high mortality rate. Platelet activating factor acetylhydrolase 1B3 (PAFAH1B3), a cancer-relevant molecular, was found to play a vital role in tumorigenesis and aggressiveness in several cancer types. However, the roles and the regulating mechanisms of PAFAH1B3 in osteosarcoma progression remain unclear. PAFAH1B3 expression was detected by immunohistochemistry in 83 osteosarcoma tissues and 44 paired adjacent normal bone tissues. In vitro, loss-of-function assay was performed to explore the role of PAFAH1B3 in osteosarcoma cells. Tumor xenograft growth assay was used to verify the effect of PAFAH1B3 knockdown on osteosarcoma growth in vivo. Chip assay was carried out to investigate the mechanism in osteosarcoma proliferation regulated by PAFAH1B3. PAFAH1B3 was overexpressed in osteosarcoma tissues and cell lines. Moreover, PAFAH1B3 knockdown inhibited osteosarcoma cell proliferation and promoted apoptosis in vitro, and also suppressed osteosarcoma growth in vivo. Furthermore, the proliferative effect of PAFAH1B3 in osteosarcoma was related to the regulation of the expression of EIF4EBP1, MYC, PTGS2 and RPS6KB1. This study demonstrated the biological function of PAFAH1B3 on osteosarcoma proliferation. This research suggested that PAFAH1B3 could be a novel therapeutic target for osteosarcoma patients.
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Affiliation(s)
- Jian Fan
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai, China
| | - Yi Yang
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai, China
| | - Ji-Kui Qian
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai, China
| | - Xin Zhang
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai, China
| | - Jia-Qing Ji
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai, China
| | - Li Zhang
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai, China
| | - Shan-Zhu Li
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai, China
| | - Feng Yuan
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai, China
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The Reeler Mouse: A Translational Model of Human Neurological Conditions, or Simply a Good Tool for Better Understanding Neurodevelopment? J Clin Med 2019; 8:jcm8122088. [PMID: 31805691 PMCID: PMC6947477 DOI: 10.3390/jcm8122088] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/26/2019] [Accepted: 11/28/2019] [Indexed: 12/25/2022] Open
Abstract
The first description of the Reeler mutation in mouse dates to more than fifty years ago, and later, its causative gene (reln) was discovered in mouse, and its human orthologue (RELN) was demonstrated to be causative of lissencephaly 2 (LIS2) and about 20% of the cases of autosomal-dominant lateral temporal epilepsy (ADLTE). In both human and mice, the gene encodes for a glycoprotein referred to as reelin (Reln) that plays a primary function in neuronal migration during development and synaptic stabilization in adulthood. Besides LIS2 and ADLTE, RELN and/or other genes coding for the proteins of the Reln intracellular cascade have been associated substantially to other conditions such as spinocerebellar ataxia type 7 and 37, VLDLR-associated cerebellar hypoplasia, PAFAH1B1-associated lissencephaly, autism, and schizophrenia. According to their modalities of inheritances and with significant differences among each other, these neuropsychiatric disorders can be modeled in the homozygous (reln−/−) or heterozygous (reln+/−) Reeler mouse. The worth of these mice as translational models is discussed, with focus on their construct and face validity. Description of face validity, i.e., the resemblance of phenotypes between the two species, centers onto the histological, neurochemical, and functional observations in the cerebral cortex, hippocampus, and cerebellum of Reeler mice and their human counterparts.
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Vandenberghe LTM, Heindryckx B, Smits K, Szymanska K, Ortiz-Escribano N, Ferrer-Buitrago M, Pavani K, Peelman L, Deforce D, De Sutter P, Van Soom A, De Schauwer C. Platelet-activating factor acetylhydrolase 1B3 (PAFAH1B3) is required for the formation of the meiotic spindle during in vitro oocyte maturation. Reprod Fertil Dev 2019; 30:1739-1750. [PMID: 30008286 DOI: 10.1071/rd18019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 06/06/2018] [Indexed: 11/23/2022] Open
Abstract
Platelet-activating factor (PAF) is a well-described autocrine growth factor involved in several reproductive processes and is tightly regulated by its hydrolysing enzyme, PAF acetylhydrolase 1B (PAFAH1B). This intracellular enzyme consists of three subunits: one regulatory, 1B1, and two catalytic, 1B2 and 1B3. PAFAH1B3 has remained uncharacterised until now. Here, we report that PAFAH1B3 is present during the different stages of the first meiotic division in bovine, murine and human oocytes. In these species, the PAFAH1B3 subunit was clearly present in the germinal vesicle, while at metaphase I and II, it localised primarily at the meiotic spindle structure. In cattle, manipulation of the microtubules of the spindle by nocodazole, taxol or cryopreservation revealed a close association with PAFAH1B3. On the other hand, disruption of the enzyme activity either by P11, a selective inhibitor of PAFAH1B3, or by PAFAH1B3 antibody microinjection, caused arrest at the MI stage with defective spindle morphology and consequent failure of first polar body extrusion. In conclusion, our results show that one of the catalytic subunits of PAFAH1B, namely PAFAH1B3, is present in bovine, murine and human oocytes and that it plays a functional role in spindle formation and meiotic progression during bovine oocyte maturation.
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Affiliation(s)
- L T M Vandenberghe
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - B Heindryckx
- Ghent-Fertility and Stem Cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, 9000 Ghent, Belgium
| | - K Smits
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - K Szymanska
- Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| | - N Ortiz-Escribano
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - M Ferrer-Buitrago
- Ghent-Fertility and Stem Cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, 9000 Ghent, Belgium
| | - K Pavani
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - L Peelman
- Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, 9820 Merelbeke, Belgium
| | - D Deforce
- Laboratory of Pharmaceutical Biotechnology, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium
| | - P De Sutter
- Ghent-Fertility and Stem Cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, 9000 Ghent, Belgium
| | - A Van Soom
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - C De Schauwer
- Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
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7
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Li CL, Chu CH, Lee HC, Chou MC, Liu CK, Chen CH, Ke LY, Chen SL. Immunoregulatory effects of very low density lipoprotein from healthy individuals and metabolic syndrome patients on glial cells. Immunobiology 2019; 224:632-637. [PMID: 31402151 DOI: 10.1016/j.imbio.2019.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/08/2019] [Accepted: 07/30/2019] [Indexed: 01/07/2023]
Abstract
Epidemiological studies have reported that elderly patients with metabolic syndrome (MetS) are significantly more likely to develop neuronal degenerative diseases than those without MetS. Our previous study showed that patients with MetS had significantly higher levels of negatively charged very low density lipoproteins (VLDLs) in the plasma than healthy controls. Highly electronegative VLDL is a key risk factor for endothelial dysfunction and atrial fibrillation. However, the impact of negatively charged VLDL in brain immunity remains unclear. In this study, VLDLs were isolated from normal healthy (nVLDL) individuals or patients with MetS (metVLDL). Primary astroglia and microglia mixed cell cultures as well as microglial-enriched cultures were used to test the effects of VLDLs. Microglia/astroglia activation as evidenced by their morphological changes and production of pro-inflammatory factors, such as tumor necrosis factor-α (TNF-α) and prostaglandin E2 (PGE2), were assessed by immunofluorescence staining and ELISA, respectively. Our results showed that metVLDLs mainly act on the microglia, and not the astroglia, with low concentration (0.05-0.5 μg/mL) inducing cell morphological changes and decreased cellular processes in the microglia. However, nVLDL treatment at these concentrations had no effects on microglia and astroglia. Most importantly, TNF-α and PGE2 levels significantly increased in the microglia treated with metVLDL via a dose-dependent manner. Together, our data indicate that metVLDLs can contribute to MetS-associated brain disorders through microglia activation and neuroinflammation.
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Affiliation(s)
- Chia-Ling Li
- Graduate Institute of Medicine & M.Sc. Program in Tropical Medicine, College of Medicine, Kaohsiung Medical University (KMU), Kaohsiung, Taiwan, ROC
| | - Chun-Hsien Chu
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Hsiang-Chun Lee
- Division of Cardiology, Department of Internal Medicine, KMU Hospital, Kaohsiung, Taiwan, ROC; Center for Lipid Bioscience, Lipid Science and Aging Research Center, College of Medicine, KMU, Kaohsiung, Taiwan, ROC
| | - Mei-Chuan Chou
- Graduate Institute of Clinical Medicine, College of Medicine, KMU, Kaohsiung, Taiwan, ROC; Department of Neurology, Kaohsiung Municipal Ta-Tung Hospital, KMU, Kaohsiung, Taiwan, ROC; Division of Neurology, Department of Internal Medicine, KMU Hospital, Kaohsiung, Taiwan, ROC
| | - Ching-Kuan Liu
- Division of Neurology, Department of Internal Medicine, KMU Hospital, Kaohsiung, Taiwan, ROC; Department of Neurology, Faculty of Medicine, College of Medicine, KMU, Kaohsiung, Taiwan, ROC
| | - Chu-Huang Chen
- Center for Lipid Bioscience, Lipid Science and Aging Research Center, College of Medicine, KMU, Kaohsiung, Taiwan, ROC; Vascular and Medicinal Research, Texas Heart Institute, Houston, TX, USA
| | - Liang-Yin Ke
- Center for Lipid Bioscience, Lipid Science and Aging Research Center, College of Medicine, KMU, Kaohsiung, Taiwan, ROC
| | - Shiou-Lan Chen
- Graduate Institute of Medicine & M.Sc. Program in Tropical Medicine, College of Medicine, Kaohsiung Medical University (KMU), Kaohsiung, Taiwan, ROC; Department of Medical Research, KMU Hospital, Kaohsiung, Taiwan, ROC; Department of Psychiatry, College of Medicine, NCKU, Tainan, Taiwan, ROC.
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8
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Xu J, Zang Y, Cao S, Lei D, Pan X. Aberrant expression of PAFAH1B3 associates with poor prognosis and affects proliferation and aggressiveness in hypopharyngeal squamous cell carcinoma. Onco Targets Ther 2019; 12:2799-2808. [PMID: 31043794 PMCID: PMC6469483 DOI: 10.2147/ott.s196324] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background Hypopharyngeal squamous cell carcinoma (HSCC) is among the most lethal tumors encountered in the head and neck, and currently lacks satisfactory therapeutic targets. Platelet activating factor acetylhydrolase 1B3 (PAFAH1B3), a cancer-relevant metabolic driver, is reported to play a critical role in controlling tumorigenesis and aggressiveness in several types of cancers. However, the role of PAFAH1B3 in HSCC progression has not yet been identified. Methods The expression pattern of PAFAH1B3 was examined using immunohistochemistry in 83 HSCC tumor tissues and 44 paired adjacent non-tumor samples. Univariate and multivariate analyses were conducted to explore its association with prognosis of HSCC. In vitro loss-of-function assays were performed to explore the impact of PAFAH1B3 knockdown on the biological phenotype of the human HSCC cell line, ie, FaDu cells. Results PAFAH1B3 was overly expressed in the HSCC tumor tissues compared with the adjacent non-tumor samples. Moreover, high expression of PAFAH1B3 was positively correlated with cervical lymph node metastasis. PAFAH1B3 overexpression was associated with poor outcome in HSCC, but it was not an independent prognostic indicator. Furthermore, in vitro loss-of function experiments demonstrated that PAFAH1B3 knockdown suppressed cell proliferation by inducing apoptosis and disrupting cell cycle process, and the migratory and invasive capacities were also attenuated in the absence of PAFAH1B3. Conclusion This study for the first time demonstrated the clinical value and the role of PAFAH1B3 in the biological function of HSCC. This work suggested that PAFAH1B3 might serve as a potential therapeutic target for HSCC patients.
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Affiliation(s)
- Jianing Xu
- Department of Otorhinolaryngology, Qilu Hospital, Shandong University, Jinan, Shandong 250012, People's Republic of China, .,NHC Key Laboratory of Otorhinolaryngology, Shandong University, Jinan, Shandong 250012, People's Republic of China,
| | - Yuanwei Zang
- Department of Urology, Qilu Hospital, Shandong University, Jinan, Shandong 250012, China
| | - Shengda Cao
- Department of Otorhinolaryngology, Qilu Hospital, Shandong University, Jinan, Shandong 250012, People's Republic of China, .,NHC Key Laboratory of Otorhinolaryngology, Shandong University, Jinan, Shandong 250012, People's Republic of China,
| | - Dapeng Lei
- Department of Otorhinolaryngology, Qilu Hospital, Shandong University, Jinan, Shandong 250012, People's Republic of China, .,NHC Key Laboratory of Otorhinolaryngology, Shandong University, Jinan, Shandong 250012, People's Republic of China,
| | - Xinliang Pan
- Department of Otorhinolaryngology, Qilu Hospital, Shandong University, Jinan, Shandong 250012, People's Republic of China, .,NHC Key Laboratory of Otorhinolaryngology, Shandong University, Jinan, Shandong 250012, People's Republic of China,
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The Role of APOE and TREM2 in Alzheimer's Disease-Current Understanding and Perspectives. Int J Mol Sci 2018; 20:ijms20010081. [PMID: 30587772 PMCID: PMC6337314 DOI: 10.3390/ijms20010081] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 12/19/2018] [Accepted: 12/21/2018] [Indexed: 12/12/2022] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia worldwide. The extracellular deposits of Amyloid beta (Aβ) in the brain-called amyloid plaques, and neurofibrillary tangles-intracellular tau aggregates, are morphological hallmarks of the disease. The risk for AD is a complicated interplay between aging, genetic risk factors, and environmental influences. One of the Apolipoprotein E (APOE) alleles-APOEε4, is the major genetic risk factor for late-onset AD (LOAD). APOE is the primary cholesterol carrier in the brain, and plays an essential role in lipid trafficking, cholesterol homeostasis, and synaptic stability. Recent genome-wide association studies (GWAS) have identified other candidate LOAD risk loci, as well. One of those is the triggering receptor expressed on myeloid cells 2 (TREM2), which, in the brain, is expressed primarily by microglia. While the function of TREM2 is not fully understood, it promotes microglia survival, proliferation, and phagocytosis, making it important for cell viability and normal immune functions in the brain. Emerging evidence from protein binding assays suggests that APOE binds to TREM2 and APOE-containing lipoproteins in the brain as well as periphery, and are putative ligands for TREM2, thus raising the possibility of an APOE-TREM2 interaction modulating different aspects of AD pathology, potentially in an isoform-specific manner. This review is focusing on the interplay between APOE isoforms and TREM2 in association with AD pathology.
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Canet-Pons J, Schubert R, Duecker RP, Schrewe R, Wölke S, Kieslich M, Schnölzer M, Chiocchetti A, Auburger G, Zielen S, Warnken U. Ataxia telangiectasia alters the ApoB and reelin pathway. Neurogenetics 2018; 19:237-255. [DOI: 10.1007/s10048-018-0557-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/09/2018] [Indexed: 02/07/2023]
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The Reelin Receptors Apolipoprotein E receptor 2 (ApoER2) and VLDL Receptor. Int J Mol Sci 2018; 19:ijms19103090. [PMID: 30304853 PMCID: PMC6213145 DOI: 10.3390/ijms19103090] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/03/2018] [Accepted: 10/03/2018] [Indexed: 01/28/2023] Open
Abstract
Apolipoprotein E receptor 2 (ApoER2) and VLDL receptor belong to the low density lipoprotein receptor family and bind apolipoprotein E. These receptors interact with the clathrin machinery to mediate endocytosis of macromolecules but also interact with other adapter proteins to perform as signal transduction receptors. The best characterized signaling pathway in which ApoER2 and VLDL receptor (VLDLR) are involved is the Reelin pathway. This pathway plays a pivotal role in the development of laminated structures of the brain and in synaptic plasticity of the adult brain. Since Reelin and apolipoprotein E, are ligands of ApoER2 and VLDLR, these receptors are of interest with respect to Alzheimer’s disease. We will focus this review on the complex structure of ApoER2 and VLDLR and a recently characterized ligand, namely clusterin.
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12
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Lin CC, Lo MC, Moody R, Jiang H, Harouaka R, Stevers N, Tinsley S, Gasparyan M, Wicha M, Sun D. Targeting LRP8 inhibits breast cancer stem cells in triple-negative breast cancer. Cancer Lett 2018; 438:165-173. [PMID: 30227220 DOI: 10.1016/j.canlet.2018.09.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/23/2018] [Accepted: 09/11/2018] [Indexed: 12/30/2022]
Abstract
Triple-negative breast cancer (TNBC) is the most difficult subtype of breast cancer to treat due to a paucity of effective targeted therapies. Many studies have reported that breast cancer stem cells (BCSCs) are enriched in TNBC and are responsible for chemoresistance and metastasis. In this study, we identify LRP8 as a novel positive regulator of BCSCs in TNBC. LRP8 is highly expressed in TNBC compared to other breast cancer subtypes and its genomic locus is amplified in 24% of TNBC tumors. Knockdown of LRP8 in TNBC cell lines inhibits Wnt/β-catenin signaling, decreases BCSCs, and suppresses tumorigenic potential in xenograft models. LRP8 knockdown also induces a more differentiated, luminal-epithelial phenotype and thus sensitizes the TNBC cells to chemotherapy. Together, our study highlights LRP8 as a novel therapeutic target for TNBC as inhibition of LRP8 can attenuate Wnt/β-catenin signaling to suppress BCSCs.
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Affiliation(s)
- Chang-Ching Lin
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Miao-Chia Lo
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Rebecca Moody
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109, USA; Chemical Biology Program, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Hui Jiang
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ramdane Harouaka
- Department of Internal Medicine, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI, 48109, USA
| | - Nicholas Stevers
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Samantha Tinsley
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Mari Gasparyan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Max Wicha
- Department of Internal Medicine, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI, 48109, USA
| | - Duxin Sun
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, 48109, USA; Chemical Biology Program, University of Michigan, Ann Arbor, MI, 48109, USA.
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13
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The functions of Reelin in membrane trafficking and cytoskeletal dynamics: implications for neuronal migration, polarization and differentiation. Biochem J 2017; 474:3137-3165. [PMID: 28887403 DOI: 10.1042/bcj20160628] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 07/27/2017] [Accepted: 08/01/2017] [Indexed: 02/06/2023]
Abstract
Reelin is a large extracellular matrix protein with relevant roles in mammalian central nervous system including neurogenesis, neuronal polarization and migration during development; and synaptic plasticity with its implications in learning and memory, in the adult. Dysfunctions in reelin signaling are associated with brain lamination defects such as lissencephaly, but also with neuropsychiatric diseases like autism, schizophrenia and depression as well with neurodegeneration. Reelin signaling involves a core pathway that activates upon reelin binding to its receptors, particularly ApoER2 (apolipoprotein E receptor 2)/LRP8 (low-density lipoprotein receptor-related protein 8) and very low-density lipoprotein receptor, followed by Src/Fyn-mediated phosphorylation of the adaptor protein Dab1 (Disabled-1). Phosphorylated Dab1 (pDab1) is a hub in the signaling cascade, from which several other downstream pathways diverge reflecting the different roles of reelin. Many of these pathways affect the dynamics of the actin and microtubular cytoskeleton, as well as membrane trafficking through the regulation of the activity of small GTPases, including the Rho and Rap families and molecules involved in cell polarity. The complexity of reelin functions is reflected by the fact that, even now, the precise mode of action of this signaling cascade in vivo at the cellular and molecular levels remains unclear. This review addresses and discusses in detail the participation of reelin in the processes underlying neurogenesis, neuronal migration in the cerebral cortex and the hippocampus; and the polarization, differentiation and maturation processes that neurons experiment in order to be functional in the adult brain. In vivo and in vitro evidence is presented in order to facilitate a better understanding of this fascinating system.
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14
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Pohlkamp T, Wasser CR, Herz J. Functional Roles of the Interaction of APP and Lipoprotein Receptors. Front Mol Neurosci 2017; 10:54. [PMID: 28298885 PMCID: PMC5331069 DOI: 10.3389/fnmol.2017.00054] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 02/16/2017] [Indexed: 11/24/2022] Open
Abstract
The biological fates of the key initiator of Alzheimer’s disease (AD), the amyloid precursor protein (APP), and a family of lipoprotein receptors, the low-density lipoprotein (LDL) receptor-related proteins (LRPs) and their molecular roles in the neurodegenerative disease process are inseparably interwoven. Not only does APP bind tightly to the extracellular domains (ECDs) of several members of the LRP group, their intracellular portions are also connected through scaffolds like the one established by FE65 proteins and through interactions with adaptor proteins such as X11/Mint and Dab1. Moreover, the ECDs of APP and LRPs share common ligands, most notably Reelin, a regulator of neuronal migration during embryonic development and modulator of synaptic transmission in the adult brain, and Agrin, another signaling protein which is essential for the formation and maintenance of the neuromuscular junction (NMJ) and which likely also has critical, though at this time less well defined, roles for the regulation of central synapses. Furthermore, the major independent risk factors for AD, Apolipoprotein (Apo) E and ApoJ/Clusterin, are lipoprotein ligands for LRPs. Receptors and ligands mutually influence their intracellular trafficking and thereby the functions and abilities of neurons and the blood-brain-barrier to turn over and remove the pathological product of APP, the amyloid-β peptide. This article will review and summarize the molecular mechanisms that are shared by APP and LRPs and discuss their relative contributions to AD.
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Affiliation(s)
- Theresa Pohlkamp
- Department of Molecular Genetics, UT Southwestern Medical CenterDallas, TX, USA; Center for Translational Neurodegeneration Research, UT Southwestern Medical CenterDallas, TX, USA
| | - Catherine R Wasser
- Department of Molecular Genetics, UT Southwestern Medical CenterDallas, TX, USA; Center for Translational Neurodegeneration Research, UT Southwestern Medical CenterDallas, TX, USA
| | - Joachim Herz
- Department of Molecular Genetics, UT Southwestern Medical CenterDallas, TX, USA; Center for Translational Neurodegeneration Research, UT Southwestern Medical CenterDallas, TX, USA; Department of Neuroscience, UT Southwestern Medical CenterDallas, TX, USA; Department of Neurology and Neurotherapeutics, UT Southwestern Medical CenterDallas, TX, USA
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15
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Chai X, Frotscher M. How does Reelin signaling regulate the neuronal cytoskeleton during migration? NEUROGENESIS 2016; 3:e1242455. [PMID: 28265585 DOI: 10.1080/23262133.2016.1242455] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 09/15/2016] [Accepted: 09/25/2016] [Indexed: 01/17/2023]
Abstract
Neuronal migration is an essential step in the formation of laminated brain structures. In the developing cerebral cortex, pyramidal neurons migrate toward the Reelin-containing marginal zone. Reelin is an extracellular matrix protein synthesized by Cajal-Retzius cells. In this review, we summarize our recent results and hypotheses on how Reelin might regulate neuronal migration by acting on the actin and microtubule cytoskeleton. By binding to ApoER2 receptors on the migrating neurons, Reelin induces stabilization of the leading processes extending toward the marginal zone, which involves Dab1 phosphorylation, adhesion molecule expression, cofilin phosphorylation and inhibition of tau phosphorylation. By binding to VLDLR and integrin receptors, Reelin interacts with Lis1 and induces nuclear translocation, accompanied by the ubiquitination of phosphorylated Dab1. Eventually Reelin induces clustering of its receptors resulting in the endocytosis of a Reelin/receptor complex (particularly VLDLR). The resulting decrease in Reelin contributes to neuronal arrest at the marginal zone.
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Affiliation(s)
- Xuejun Chai
- Institute for Structural Neurobiology, Center for Molecular Neurobiology Hamburg (ZMNH) , Hamburg, Germany
| | - Michael Frotscher
- Institute for Structural Neurobiology, Center for Molecular Neurobiology Hamburg (ZMNH) , Hamburg, Germany
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16
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Simard-Bisson C, Bidoggia J, Larouche D, Guérin SL, Blouin R, Hirai SI, Germain L. A Role for DLK in Microtubule Reorganization to the Cell Periphery and in the Maintenance of Desmosomal and Tight Junction Integrity. J Invest Dermatol 2016; 137:132-141. [PMID: 27519653 DOI: 10.1016/j.jid.2016.07.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 07/13/2016] [Accepted: 07/28/2016] [Indexed: 12/24/2022]
Abstract
Dual leucine zipper-bearing kinase (DLK) is an inducer of keratinocyte differentiation, a complex process also involving microtubule reorganization to the cell periphery. However, signaling mechanisms involved in this process remain to be elucidated. Here, we demonstrate that DLK enhances and is required for microtubule reorganization to the cell periphery in human cell culture models and in Dlk knockout mouse embryos. In tissue-engineered skins with reduced DLK expression, cortical distribution of two microtubule regulators, LIS1 and HSP27, is impaired as well as desmosomal and tight junction integrity. Altered cortical distribution of desmosomal and tight junction proteins was also confirmed in Dlk knockout mouse embryos. Finally, desmosomal and tight junction defects were also observed after microtubule disruption in nocodazole-treated tissue-engineered skins, thus confirming a role for microtubules in the maintenance of these types of cell junctions. Globally, this study demonstrates that DLK is a key regulator of microtubule reorganization to the cell periphery during keratinocyte differentiation and that this process is required for the maintenance of desmosomal and tight junction integrity.
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Affiliation(s)
- Carolyne Simard-Bisson
- Centre de Recherche du CHU de Québec-Université Laval and Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Québec, Québec, Canada; Département de Chirurgie, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Julie Bidoggia
- Centre de Recherche du CHU de Québec-Université Laval and Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Québec, Québec, Canada
| | - Danielle Larouche
- Centre de Recherche du CHU de Québec-Université Laval and Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Québec, Québec, Canada; Département de Chirurgie, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Sylvain L Guérin
- Centre de Recherche du CHU de Québec-Université Laval and Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Québec, Québec, Canada; Centre Universitaire d'Ophtalmologie (CUO)-Recherche, Québec, Québec, Canada; Département d'Ophtalmologie, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Richard Blouin
- Département de biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Syu-Ichi Hirai
- Department of Molecular Biology, Yokohama City University Graduate School of Medicine, Yokohama, Japan; Department of Biology, Wakayama Medical University School of Medicine, Wakayama, Japan
| | - Lucie Germain
- Centre de Recherche du CHU de Québec-Université Laval and Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Québec, Québec, Canada; Département de Chirurgie, Faculté de Médecine, Université Laval, Québec, Québec, Canada; Département d'Ophtalmologie, Faculté de Médecine, Université Laval, Québec, Québec, Canada.
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17
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Bock HH, May P. Canonical and Non-canonical Reelin Signaling. Front Cell Neurosci 2016; 10:166. [PMID: 27445693 PMCID: PMC4928174 DOI: 10.3389/fncel.2016.00166] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 06/08/2016] [Indexed: 12/11/2022] Open
Abstract
Reelin is a large secreted glycoprotein that is essential for correct neuronal positioning during neurodevelopment and is important for synaptic plasticity in the mature brain. Moreover, Reelin is expressed in many extraneuronal tissues; yet the roles of peripheral Reelin are largely unknown. In the brain, many of Reelin's functions are mediated by a molecular signaling cascade that involves two lipoprotein receptors, apolipoprotein E receptor-2 (Apoer2) and very low density-lipoprotein receptor (Vldlr), the neuronal phosphoprotein Disabled-1 (Dab1), and members of the Src family of protein tyrosine kinases as crucial elements. This core signaling pathway in turn modulates the activity of adaptor proteins and downstream protein kinase cascades, many of which target the neuronal cytoskeleton. However, additional Reelin-binding receptors have been postulated or described, either as coreceptors that are essential for the activation of the "canonical" Reelin signaling cascade involving Apoer2/Vldlr and Dab1, or as receptors that activate alternative or additional signaling pathways. Here we will give an overview of canonical and alternative Reelin signaling pathways, molecular mechanisms involved, and their potential physiological roles in the context of different biological settings.
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Affiliation(s)
- Hans H Bock
- Clinic of Gastroenterology and Hepatology, Heinrich-Heine-University Düsseldorf Düsseldorf, Germany
| | - Petra May
- Clinic of Gastroenterology and Hepatology, Heinrich-Heine-University Düsseldorf Düsseldorf, Germany
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18
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Lee GH, D'Arcangelo G. New Insights into Reelin-Mediated Signaling Pathways. Front Cell Neurosci 2016; 10:122. [PMID: 27242434 PMCID: PMC4860420 DOI: 10.3389/fncel.2016.00122] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 04/27/2016] [Indexed: 11/21/2022] Open
Abstract
Reelin, a multifunctional extracellular protein that is important for mammalian brain development and function, is secreted by different cell types in the prenatal or postnatal brain. The spatiotemporal regulation of Reelin expression and distribution during development relates to its multifaceted function in the brain. Prenatally Reelin controls neuronal radial migration and proper positioning in cortical layers, whereas postnatally Reelin promotes neuronal maturation, synaptic formation and plasticity. The molecular mechanisms underlying the distinct biological functions of Reelin during and after brain development involve unique and overlapping signaling pathways that are activated following Reelin binding to its cell surface receptors. Distinct Reelin ligand isoforms, such as the full-length protein or fragments generated by proteolytic cleavage differentially affect the activity of downstream signaling pathways. In this review, we discuss recent advances in our understanding of the signaling transduction pathways activated by Reelin that regulate different aspects of brain development and function. A core signaling machinery, including ApoER2/VLDLR receptors, Src/Fyn kinases, and the adaptor protein Dab1, participates in all known aspects of Reelin biology. However, distinct downstream mechanisms, such as the Crk/Rap1 pathway and cell adhesion molecules, play crucial roles in the control of neuronal migration, whereas the PI3K/Akt/mTOR pathway appears to be more important for dendrite and spine development. Finally, the NMDA receptor (NMDAR) and an unidentified receptor contribute to the activation of the MEK/Erk1/2 pathway leading to the upregulation of genes involved in synaptic plasticity and learning. This knowledge may provide new insight into neurodevelopmental or neurodegenerative disorders that are associated with Reelin dysfunction.
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Affiliation(s)
- Gum Hwa Lee
- College of Pharmacy, Chosun University Gwangju, South Korea
| | - Gabriella D'Arcangelo
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey Piscataway, NJ, USA
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19
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Abstract
Platelet-activating factor (PAF) is a phospholipid mediator whose synthesis and degradation depend on specific sets of enzymes. PAF-acetylhydrolase (PAF-AH) hydrolyzes the acetyl moiety of PAF at its sn-2 position and thereby inactivates it. PAF-AH Ib, originally identified in brain, exists in the cytoplasm of many (probably all) types of mammalian cells and tissues. PAF-AH Ib consists of three subunits (α1, α2, and β), in which the α subunits provide the catalytic activity. The finding that the β subunit is the product of the causative gene for Miller-Dieker lissencephaly led to extensive analyses of PAF-AH Ib subunits in the field of cell biology and neurobiology. More than 20 molecules are known to bind to PAF-AH Ib subunits, and PAF-AH Ib has been implicated in neuronal development, neuronal functions, Alzheimer's disease, bipolar disorder, cancer, spermatogenesis, and tolerance to hypoxia. However, in almost all of these cases, how the catalytic activity is involved and the identity of the most important substrate of this enzyme are unclear. In this chapter, the structure and functions of PAF-AH Ib and its subunit proteins are summarized and their contributions to human diseases are discussed.
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Affiliation(s)
- Mitsuharu Hattori
- Department of Biomedical Science, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi, Japan
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, the University of Tokyo, Tokyo, Japan.
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20
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NDEL1 was decreased in the CA3 region but increased in the hippocampal blood vessel network during the spontaneous seizure period after pilocarpine-induced status epilepticus. Neuroscience 2014; 268:276-83. [DOI: 10.1016/j.neuroscience.2014.03.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Revised: 03/14/2014] [Accepted: 03/17/2014] [Indexed: 12/19/2022]
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21
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Förster E. Reelin, neuronal polarity and process orientation of cortical neurons. Neuroscience 2014; 269:102-11. [PMID: 24657457 DOI: 10.1016/j.neuroscience.2014.03.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 03/01/2014] [Accepted: 03/04/2014] [Indexed: 12/22/2022]
Abstract
Deficient reelin signaling leads to characteristic layering malformations in the cerebral cortex and causes polarity defects of cortical neurons. Since the discovery of reelin much has been learned about the molecular mechanisms that underlie the characteristic defects of layering defects in the reeler mutant. More recent studies provided insights in the crosstalk between reelin signaling and molecular pathways that control polarity development of radially migrating neurons. The present review summarizes and discusses recent findings on the role of reelin in modulating polarization and process orientation of neurons in the neocortex and hippocampus.
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Affiliation(s)
- E Förster
- Institute of Neuroanatomy, University Medical Center Hamburg Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
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22
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Belvindrah R, Nosten-Bertrand M, Francis F. Neuronal migration and its disorders affecting the CA3 region. Front Cell Neurosci 2014; 8:63. [PMID: 24624057 PMCID: PMC3941003 DOI: 10.3389/fncel.2014.00063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 02/13/2014] [Indexed: 11/15/2022] Open
Abstract
In this review, we focus on CA3 neuronal migration disorders in the rodent. We begin by introducing the main steps of hippocampal development, and we summarize characteristic hippocampal malformations in human. We then describe various mouse mutants showing structural hippocampal defects. Notably, genes identified in human cortical neuronal migration disorders consistently give rise to a CA3 phenotype when mutated in the mouse. We successively describe their molecular, physiological and behavioral phenotypes that together contribute to a better understanding of CA3-dependent functions. We finally discuss potential factors underlying the CA3 vulnerability revealed by these mouse mutants and that may also contribute to other human neurological and psychiatric disorders.
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Affiliation(s)
- Richard Belvindrah
- INSERM UMR-S 839 Paris, France ; Sorbonne Universités, Université Pierre et Marie Curie, Univ Paris 06 Paris, France ; Institut du Fer à Moulin Paris, France
| | - Marika Nosten-Bertrand
- INSERM UMR-S 839 Paris, France ; Sorbonne Universités, Université Pierre et Marie Curie, Univ Paris 06 Paris, France ; Institut du Fer à Moulin Paris, France
| | - Fiona Francis
- INSERM UMR-S 839 Paris, France ; Sorbonne Universités, Université Pierre et Marie Curie, Univ Paris 06 Paris, France ; Institut du Fer à Moulin Paris, France
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23
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Reelin in the Years: Controlling Neuronal Migration and Maturation in the Mammalian Brain. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/597395] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The extracellular protein Reelin was initially identified as an essential factor in the control of neuronal migration and layer formation in the developing mammalian brain. In the years following its discovery, however, it became clear that Reelin is a multifunctional protein that controls not only the positioning of neurons in the developing brain, but also their growth, maturation, and synaptic activity in the adult brain. In this review, we will highlight the major discoveries of the biological activities of Reelin and the underlying molecular mechanisms that affect the development and function of the mammalian brain, from embryonic ages to adulthood.
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24
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Dubuissez M, Faiderbe P, Pinte S, Dehennaut V, Rood BR, Leprince D. The Reelin receptors ApoER2 and VLDLR are direct target genes of HIC1 (Hypermethylated In Cancer 1). Biochem Biophys Res Commun 2013; 440:424-30. [PMID: 24076391 DOI: 10.1016/j.bbrc.2013.09.091] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 09/17/2013] [Indexed: 11/16/2022]
Abstract
The tumor suppressor gene HIC1 (Hypermethylated In Cancer 1) is located in 17p13.3 a region frequently hypermethylated or deleted in tumors and in a contiguous-gene syndrome, the Miller-Dieker syndrome which includes classical lissencephaly (smooth brain) and severe developmental defects. HIC1 encodes a transcriptional repressor involved in the regulation of growth control, DNA damage response and cell migration properties. We previously demonstrated that the membrane-associated G-protein-coupled receptors CXCR7, ADRB2 and the tyrosine kinase receptor EphA2 are direct target genes of HIC1. Here we show that ectopic expression of HIC1 in U2OS and MDA-MB-231 cell lines decreases expression of the ApoER2 and VLDLR genes, encoding two canonical tyrosine kinase receptors for Reelin. Conversely, knock-down of endogenous HIC1 in BJ-Tert normal human fibroblasts through RNA interference results in the up-regulation of these two Reelin receptors. Finally, through chromatin immunoprecipitation (ChIP) in BJ-Tert fibroblasts, we demonstrate that HIC1 is a direct transcriptional repressor of ApoER2 and VLDLR. These data provide evidence that HIC1 is a new regulator of the Reelin pathway which is essential for the proper migration of neuronal precursors during the normal development of the cerebral cortex, of Purkinje cells in the cerebellum and of mammary epithelial cells. Deregulation of this pathway through HIC1 inactivation or deletion may contribute to its role in tumor promotion. Moreover, HIC1, through the direct transcriptional repression of ATOH1 and the Reelin receptors ApoER2 and VLDLR, could play an essential role in normal cerebellar development.
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Affiliation(s)
- Marion Dubuissez
- CNRS-UMR 8161, Institut de Biologie de Lille, Université de Lille Nord de France, Institut Pasteur de Lille, IFR 142, 1 rue Calmette, BP447, 59017 Lille Cedex, France
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25
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Folsom TD, Fatemi SH. The involvement of Reelin in neurodevelopmental disorders. Neuropharmacology 2013; 68:122-35. [PMID: 22981949 PMCID: PMC3632377 DOI: 10.1016/j.neuropharm.2012.08.015] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 08/14/2012] [Accepted: 08/16/2012] [Indexed: 12/21/2022]
Abstract
Reelin is a glycoprotein that serves important roles both during development (regulation of neuronal migration and brain lamination) and in adulthood (maintenance of synaptic function). A number of neuropsychiatric disorders including autism, schizophrenia, bipolar disorder, major depression, Alzheimer's disease and lissencephaly share a common feature of abnormal Reelin expression in the brain. Altered Reelin expression has been hypothesized to impair neuronal connectivity and synaptic plasticity, leading ultimately to the cognitive deficits present in these disorders. The mechanisms for abnormal Reelin expression in some of these disorders are currently unknown although possible explanations include early developmental insults, mutations, hypermethylation of the promoter for the Reelin gene (RELN), miRNA silencing of Reelin mRNA, FMRP underexpression and Reelin processing abnormalities. Increasing Reelin expression through pharmacological therapies may help ameliorate symptoms resulting from Reelin deficits. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.
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Affiliation(s)
- Timothy D. Folsom
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN 55455, USA
| | - S. Hossein Fatemi
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN 55455, USA
- Department of Pharmacology, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN 55455, USA
- Department of Neuroscience, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN 55455, USA
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26
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Escamez T, Bahamonde O, Tabares-Seisdedos R, Vieta E, Martinez S, Echevarria D. Developmental dynamics of PAFAH1B subunits during mouse brain development. J Comp Neurol 2013; 520:3877-94. [PMID: 22522921 DOI: 10.1002/cne.23128] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Platelet-activating factor (PAF) mediates an array of biological processes in the mammalian central nervous system as a bioactive lipid messenger in synaptic function and dysfunction (plasticity, memory, and neurodegeneration). The intracellular enzyme that deacetylates the PAF (PAFAH1B) is composed of a tetramer of two catalytic subunits, ALPHA1 (PAFAH1B3) and ALPHA2 (PAFAH1B2), and a regulatory dimer of LIS1 (PAFAH1B1). We have investigated the mouse PAFAH1B subunit genes during brain development in normal mice and in mice with a hypomorphic allele for Lis1 (Lis1/sLis1; Cahana et al. [2001] Proc Natl Acad Sci U S A 98:6429-6434). We have analyzed quantitatively (by means of real-time polymerase chain reaction) and qualitatively (by in situ hybridization techniques) the amounts and expression patterns of their transcription in developing and postnatal brain, focusing mainly on differences in two laminated encephalic regions, the forebrain (telencephalon) and hindbrain (cerebellum) separately. The results revealed significant differences in cDNA content between these two brain subdivisions but, more importantly, between the LIS1 complex subunits. In addition, we found significant spatial differences in gene expression patterns. Comparison of results obtained with Lis1/sLis1 analysis also revealed significant temporal and spatial differences in Alpha1 and Lis1 expression levels. Thus, small changes in the amount of the Lis1 gene may differentially regulate expression of Alpha1 and Alpha2, depending on the brain region, which suggests different roles for each LIS1 complex subunit during neural differentiation and neural migration.
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Affiliation(s)
- Teresa Escamez
- Unidad Mixta de Investigación UVEG-UMH-CIBERSAM, Centro de Investigación Biomédica en Red en el Area de Salud Mental, 03550 San Juan de Alicante, Spain
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27
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Loss of PAFAH1B2 reduces amyloid-β generation by promoting the degradation of amyloid precursor protein C-terminal fragments. J Neurosci 2013; 32:18204-14. [PMID: 23238734 DOI: 10.1523/jneurosci.2681-12.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Amyloid-β peptide (Aβ) is believed to play a central role in the pathogenesis of Alzheimer's disease. In view of the side effects associated with inhibiting the secretases that produce Aβ, new molecular targets are required to provide alternative therapeutic options. We used RNA interference (RNAi) to systematically screen the Drosophila genome to identify genes that modulate Aβ production upon knockdown. RNAi of 41 genes in Drosophila cells significantly lowered Aβ without affecting general secretion or viability. After the γ-secretase complex components, the most potent effect was observed for platelet activating factor acetylhydrolase α (Paf-AHα), and, in mammalian cells, the effect was replicated for its ortholog PAFAH1B2. Knockdown of PAFAH1B2 strongly reduced Aβ secretion from human cells, and this effect was confirmed in primary cells derived from PAFAH1B2 knock-out mice. Reduced Aβ production was not attributable to altered β-amyloid precursor protein (APP) ectodomain shedding but was a result of an enhanced degradation of APP C-terminal fragments (CTFs) in the absence of PAFAH1B2 but not its close homolog PAFAH1B3. Enhanced degradation of APP CTFs was selective because no such effects were obtained for Notch or E-/N-cadherin. Thus, we have identified an important protein that can selectively modify Aβ generation via a novel mechanism, namely enhanced degradation of its immediate precursor. In view of the absence of a neurological phenotype in PAFAH1B2 knock-out mice, targeted downregulation of PAFAH1B2 may be a promising new strategy for lowering Aβ.
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Bechler ME, Brown WJ. PAFAH Ib phospholipase A2 subunits have distinct roles in maintaining Golgi structure and function. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:595-601. [PMID: 23262398 DOI: 10.1016/j.bbalip.2012.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 12/06/2012] [Accepted: 12/07/2012] [Indexed: 12/27/2022]
Abstract
Recent studies showed that the phospholipase subunits of Platelet Activating Factor Acetylhydrolase (PAFAH) Ib, α1 and α2 partially localize to the Golgi complex and regulate its structure and function. Using siRNA knockdown of individual subunits, we find that α1 and α2 perform overlapping and unique roles in regulating Golgi morphology, assembly, and secretory cargo trafficking. Knockdown of either α1 or α2 reduced secretion of soluble proteins, but neither single knockdown reduced secretion to the same degree as knockdown of both. Knockdown of α1 or α2 inhibited reassembly of an intact Golgi complex to the same extent as knockdown of both. Transport of VSV-G was slowed but at different steps in the secretory pathway: reduction of α1 slowed trans Golgi network to plasma membrane transport, whereas α2 loss reduced endoplasmic reticulum to Golgi trafficking. Similarly, knockdown of either subunit alone disrupted the Golgi complex but with markedly different morphologies. Finally, knockdown of α1, or double knockdown of α1 and α2, resulted in a significant redistribution of kinase dead protein kinase D from the Golgi to the plasma membrane, whereas loss of α2 alone had no such effect. These studies reveal an unexpected complexity in the regulation of Golgi structure and function by PAFAH Ib. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism.
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Affiliation(s)
- Marie E Bechler
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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Meseke M, Cavus E, Förster E. Reelin promotes microtubule dynamics in processes of developing neurons. Histochem Cell Biol 2012; 139:283-97. [PMID: 22990595 DOI: 10.1007/s00418-012-1025-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2012] [Indexed: 11/24/2022]
Abstract
The extracellular matrix protein reelin controls radial migration and layer formation of cortical neurons, in part by modulation of cytoskeletal dynamics. A stabilizing effect of reelin on the actin cytoskeleton has been described recently. However, it is poorly understood how reelin modulates microtubule dynamics. Here, we provide evidence that reelin increases microtubule assembly. This effect is mediated, at least in part, by promoting microtubule plus end dynamics in processes of developing neurons. Thus, we treated primary neuronal cultures with nocodazole to disrupt microtubules. After nocodazole washout, we found microtubule reassembly to be accelerated in the presence of reelin. Moreover, we show that reelin treatment promoted the formation of microtubule plus end binding protein 3 (EB3) comets in developing dendrites, and that EB3 immunostaining in the developing wild-type neocortex is most intense in the reelin-rich marginal zone where leading processes of radially migrating neurons project to. This characteristic EB3 staining pattern was absent in reeler. Also reassembly of nocodazole-dispersed dendritic Golgi apparati, which are closely associated to microtubules, was accelerated by reelin treatment, though with a substantially slower time course when compared to microtubule reassembly. In support of our in vitro results, we found that the subcellular distribution of α-tubulin and acetylated tubulin in reeler cortical sections differed from wild-type and from mice lacking the very low density lipoprotein receptor (VLDLR), known to bind reelin. Taken together, our results suggest that reelin promotes microtubule assembly, at least in part, by increasing microtubule plus end dynamics.
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Affiliation(s)
- Maurice Meseke
- Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
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30
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Imai H, Oomiya Y, Kikkawa S, Shoji W, Hibi M, Terashima T, Katsuyama Y. Dynamic changes in the gene expression of zebrafish Reelin receptors during embryogenesis and hatching period. Dev Growth Differ 2012; 54:253-63. [PMID: 22364494 DOI: 10.1111/j.1440-169x.2012.01327.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The brain morphology of vertebrates exhibits huge evolutionary diversity, but one of the shared morphological features unique to vertebrate brain is laminar organization of neurons. Because the Reelin signal plays important roles in the development of the laminar structures in mammalian brain, investigation of Reelin signal in lower vertebrates will give some insights into evolution of vertebrate brain morphogenesis. Although zebrafish homologues of Reelin, the ligand, and Dab1, a cytoplasmic component of the signaling pathway, have been reported, the Reelin receptor molecules of zebrafish are not reported yet. Here, we sought cDNA sequence of zebrafish homologue of the receptors, vldlr and apoer2, and examined their expression patterns by in situ hybridization. Developmental gene expression pattern of reelin, dab1, vldlr, and apoer2 in the central nervous system of zebrafish was compared, and their remarkable expression was detected in the developing laminar structures, such as the tectum and the cerebellum, and also non-laminated structures, such as the pallium. The Reelin receptors exhibited different spatial and temporal gene expression. These results suggest a possibility that duplication and subsequent functional diversity of Reelin receptors contributed to the morphological and functional evolution of vertebrate brain.
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Affiliation(s)
- Hideaki Imai
- Division of Anatomy and Neurobiology, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
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31
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Moore KD, Chen R, Cilluffo M, Golden JA, Phelps PE. Lis1 reduction causes tangential migratory errors in mouse spinal cord. J Comp Neurol 2012; 520:1198-211. [PMID: 21935943 PMCID: PMC4079006 DOI: 10.1002/cne.22768] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mutations in human LIS1 cause abnormal neuronal migration and a smooth brain phenotype known as lissencephaly. Lis1+/− (Pafah1b1) mice show defective lamination in the cerebral cortex and hippocampal formation, whereas homozygous mutations result in embryonic lethality. Given that Lis1 is highly expressed in embryonic neurons, we hypothesized that sympathetic and parasympathetic preganglionic neurons (SPNs and PPNs) would exhibit migratory defects in Lis1+/− mice. The initial radial migration of SPNs and PPNs that occurs together with somatic motor neurons appeared unaffected in Lis1+/− mice. The subsequent dorsally directed tangential migration, however, was aberrant in a subset of these neurons. At all embryonic ages analyzed, the distribution of SPNs and PPNs in Lis1+/− mice was elongated dorsoventrally compared with Lis1+/+ mice. Individual cell bodies of ectopic preganglionic neurons were found in the ventral spinal cord with their leading processes oriented along their dorsal migratory trajectory. By birth, Lis1+/− SPNs and PPNs were separated into distinct groups, those that were correctly, and those incorrectly positioned in the intermediate horn. As mispositioned SPNs and PPNs still were detected in P30 Lis1+/− mice, we conclude that these neurons ceased migration prematurely. Additionally, we found that a dorsally located group of somatic motor neurons in the lumbar spinal cord, the retrodorsolateral nucleus, showed delayed migration in Lis1+/− mice. These results suggest that Lis1 is required for the dorsally directed tangential migration of many sympathetic and parasympathetic preganglionic neurons and a subset of somatic motor neurons.
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Affiliation(s)
- Katherine D. Moore
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, California 90095-7239
| | - Renee Chen
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, California 90095-7239
| | - Marianne Cilluffo
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, California 90095-7239
| | - Jeffrey A. Golden
- Department of Pathology and Laboratory Medicine, The Children’s Hospital of Philadelphia and the University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Patricia E. Phelps
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, California 90095-7239
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Development and dysgenesis of the cerebral cortex: malformations of cortical development. Neuroimaging Clin N Am 2012; 21:483-543, vii. [PMID: 21807310 DOI: 10.1016/j.nic.2011.05.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The cerebral cortex develops in several stages from a pseudostratified epithelium at 5 weeks to an essentially complete cortex at 47 weeks. Cortical connectivity starts with thalamocortical connections in the 3rd trimester only and continues until well after birth. Vascularity adapts to proliferation and connectivity. Malformations of cortical development are classified into disorders of specification, proliferation/apoptosis, migration, and organization. However, all processes are intermingled, as for example a dysplastic cell may migrate incompletely and not connect appropriately. However, this classification is convenient for didactic purposes as long as the complex interactions between the different processes are kept in mind.
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Bechler ME, de Figueiredo P, Brown WJ. A PLA1-2 punch regulates the Golgi complex. Trends Cell Biol 2011; 22:116-24. [PMID: 22130221 DOI: 10.1016/j.tcb.2011.10.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 10/19/2011] [Accepted: 10/20/2011] [Indexed: 12/14/2022]
Abstract
The mammalian Golgi complex, trans Golgi network (TGN) and ER-Golgi intermediate compartment (ERGIC) are comprised of membrane cisternae, coated vesicles and membrane tubules, all of which contribute to membrane trafficking and maintenance of their unique architectures. Recently, a new cast of players was discovered to regulate the Golgi and ERGIC: four unrelated cytoplasmic phospholipase A (PLA) enzymes, cPLA(2)α (GIVA cPLA(2)), PAFAH Ib (GVIII PLA(2)), iPLA(2)-β (GVIA-2 iPLA(2)) and iPLA(1)γ. These ubiquitously expressed enzymes regulate membrane trafficking from specific Golgi subcompartments, although there is evidence for some functional redundancy between PAFAH Ib and cPLA(2)α. Three of these enzymes, PAFAH Ib, cPLA(2)α and iPLA(2)-β, exert effects on Golgi structure and function by inducing the formation of membrane tubules. We review our current understanding of how PLA enzymes regulate Golgi and ERGIC morphology and function.
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Affiliation(s)
- Marie E Bechler
- Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY 14853, USA
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Pawlisz AS, Feng Y. Three-dimensional regulation of radial glial functions by Lis1-Nde1 and dystrophin glycoprotein complexes. PLoS Biol 2011; 9:e1001172. [PMID: 22028625 PMCID: PMC3196477 DOI: 10.1371/journal.pbio.1001172] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 08/30/2011] [Indexed: 01/09/2023] Open
Abstract
Lis1-Nde1 integrates cerebral cortical neurogenesis with neuronal migration by stabilizing the basal-lateral surface of radial glial cells. Radial glial cells (RGCs) are distinctive neural stem cells with an extraordinary slender bipolar morphology and dual functions as precursors and migration scaffolds for cortical neurons. Here we show a novel mechanism by which the Lis1-Nde1 complex maintains RGC functions through stabilizing the dystrophin/dystroglycan glycoprotein complex (DGC). A direct interaction between Nde1 and utrophin/dystrophin allows for the assembly of a multi-protein complex that links the cytoskeleton to the extracellular matrix of RGCs to stabilize their lateral membrane, cell-cell adhesion, and radial morphology. Lis1-Nde1 mutations destabilized the DGC and resulted in deformed, disjointed RGCs and disrupted basal lamina. Besides impaired RGC self-renewal and neuronal migration arrests, Lis1-Nde1 deficiencies also led to neuronal over-migration. Additional to phenotypic resemblances of Lis1-Nde1 with DGC, strong synergistic interactions were found between Nde1 and dystroglycan in RGCs. As functional insufficiencies of LIS1, NDE1, and dystroglycan all cause lissencephaly syndromes, our data demonstrated that a three-dimensional regulation of RGC's cytoarchitecture by the Lis1-Nde1-DGC complex determines the number and spatial organization of cortical neurons as well as the size and shape of the cerebral cortex. The processes of neurogenesis and neuronal migration within the developing cerebral cortex must be tightly orchestrated to enable ordered generation and transportation of neurons to designated cortical layers. The mechanism by which these two processes are integrated remains elusive. Radial glial cells, the major neural stem cells in the developing brain, serve both as progenitors and migration scaffolds for cortical neurons as they migrate. The cortical developmental disease lissencephaly (smooth brain) is a result of defects in neurogenesis and neuronal migration, and is associated with the protein LIS1 and its binding partner NDE1. In this study, we show that several key players in human cerebral cortical development, including LIS1, NDE1, dystrophin, and dystroglycan, form a molecular complex to regulate cortical neurogenesis and neuronal migration in a mouse model. This multi-protein complex is active on the basal-lateral surface of radial glial cells, which is known to provide guidance to migrating neurons. When we depleted NDE1 in mice, dystrophin and dystroglycan were lost from the membrane and radial glial cells were deformed, indicating the importance of the multi-protein complex for proper cell morphology. This effect on morphology resulted in a loss of normal migration and cortical phenotypes similar to lissencephaly. Our findings suggest that genes that regulate the structure and function of the basal-lateral membrane of radial glial cells may integrate the dual functions of these cells and determine the size, shape, and function of the cerebral cortex.
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Affiliation(s)
- Ashley S. Pawlisz
- Department of Neurology and Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Yuanyi Feng
- Department of Neurology and Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
- * E-mail:
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35
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Zhao Y, Chen X, Yang H, Zhou L, Okoro EU, Guo Z. A novel function of apolipoprotein E: upregulation of ATP-binding cassette transporter A1 expression. PLoS One 2011; 6:e21453. [PMID: 21779326 PMCID: PMC3136925 DOI: 10.1371/journal.pone.0021453] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 05/28/2011] [Indexed: 11/18/2022] Open
Abstract
Despite the well known importance of apolipoprotein (Apo) E in cholesterol efflux, the effect of ApoE on the expression of ATP-binding cassette transporter A1 (ABCA1) has never been investigated. The objective of this study was to determine the effect of ApoE on ApoB-carrying lipoprotein-induced expression of ABCA1, a protein that mediates cholesterol efflux. Our data demonstrate that ApoB-carrying lipoproteins obtained from both wild-type and ApoE knockout mice induced ApoAI-mediated cholesterol efflux in mouse macrophages, which was associated with an enhanced ABCA1 promoter activity, and an increased ABCA1 mRNA and protein expression. In addition, these lipoproteins increased the level of phosphorylated specificity protein 1 (Sp1) and the amount of Sp1 bound to the ABCA1 promoter. However, all these inductions were significantly diminished in cells treated with ApoE-free lipoproteins, when compared to those treated with wild-type lipoproteins. Enrichment with human ApoE3 reversed the reduced inducibility of ApoE-free lipoproteins. Moreover, we observed that inhibition of Sp1 DNA-binding by mithramycin A diminished ABCA1 expression and ApoAI-mediated cholesterol efflux induced by ApoB-carrying lipoproteins, and that mutation of the Sp1-binding motif in the ABCA1 promoter region diminished ApoB-carrying lipoprotein-induced ABCA1 promoter activity. Collectively, these data suggest that ApoE associated with ApoB-carrying lipoproteins has an upregulatory role on ABCA1 expression, and that induction of Sp1 phosphorylation is a mechanism by which ApoE upregulates ABCA1 expression.
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Affiliation(s)
- Yanfeng Zhao
- Department of Physiology, Wuhan University School of Basic Medical Science, Wuhan, People's Republic of China
| | - Xinping Chen
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Hong Yang
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Lichun Zhou
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Emmanuel U. Okoro
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Zhongmao Guo
- Department of Physiology, Meharry Medical College, Nashville, Tennessee, United States of America
- * E-mail:
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Reddy SS, Connor TE, Weeber EJ, Rebeck W. Similarities and differences in structure, expression, and functions of VLDLR and ApoER2. Mol Neurodegener 2011; 6:30. [PMID: 21554715 PMCID: PMC3113299 DOI: 10.1186/1750-1326-6-30] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 05/09/2011] [Indexed: 11/29/2022] Open
Abstract
Very Low Density Lipoprotein Receptor (VLDLR) and Apolipoprotein E Receptor 2 (ApoER2) are important receptors in the brain for mediating the signaling effects of the extracellular matrix protein Reelin, affecting neuronal function in development and in the adult brain. VLDLR and ApoER2 are members of the low density lipoprotein family, which also mediates the effects of numerous other extracellular ligands, including apolipoprotein E. Although VLDLR and ApoER2 are highly homologous, they differ in a number of ways, including structural differences, expression patterns, alternative splicing, and binding of extracellular and intracellular proteins. This review aims to summarize important aspects of VLDLR and ApoER2 that may account for interesting recent findings that highlight the unique functions of each receptor.
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Affiliation(s)
- Sunil S Reddy
- Department of Neuroscience; Georgetown University Medical Center, 3970 Reservoir Rd, NW, Washington, DC, 20007, USA.
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37
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Dieckmann M, Dietrich MF, Herz J. Lipoprotein receptors--an evolutionarily ancient multifunctional receptor family. Biol Chem 2011; 391:1341-63. [PMID: 20868222 DOI: 10.1515/bc.2010.129] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The evolutionarily ancient low-density lipoprotein (LDL) receptor gene family represents a class of widely expressed cell surface receptors. Since the dawn of the first primitive multicellular organisms, several structurally and functionally distinct families of lipoprotein receptors have evolved. In accordance with the now obsolete 'one-gene-one-function' hypothesis, these cell surface receptors were originally perceived as mere transporters of lipoproteins, lipids, and nutrients or as scavenger receptors, which remove other kinds of macromolecules, such as proteases and protease inhibitors from the extracellular environment and the cell surface. This picture has since undergone a fundamental change. Experimental evidence has replaced the perception that these receptors serve merely as cargo transporters. Instead it is now clear that the transport of macromolecules is inseparably intertwined with the molecular machinery by which cells communicate with each other. Lipoprotein receptors are essentially sensors of the extracellular environment that participate in a wide range of physiological processes by physically interacting and coevolving with primary signal transducers as co-regulators. Furthermore, lipoprotein receptors modulate cellular trafficking and localization of the amyloid precursor protein (APP) and the β-amyloid peptide (Aβ), suggesting a role in the pathogenesis of Alzheimer's disease. Moreover, compelling evidence shows that LDL receptor family members are involved in tumor development and progression.
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Affiliation(s)
- Marco Dieckmann
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9046, USA
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38
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Zhao S, Frotscher M. Go or stop? Divergent roles of Reelin in radial neuronal migration. Neuroscientist 2011; 16:421-34. [PMID: 20817919 DOI: 10.1177/1073858410367521] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Neuronal migration is an essential step of brain development and is controlled by a variety of cellular proteins and extracellular matrix molecules. Reelin, an extracellular matrix protein, is required for neuronal migration. Over the past 10 years, the Reelin signaling cascade has been studied intensively. However, the role of Reelin in neuronal migration has remained unclear. Different Reelin fragments and different Reelin receptors suggest multiple functions of Reelin. In this review, the authors focus on Reelin effects on the actin cytoskeleton of migrating neurons.
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Affiliation(s)
- Shanting Zhao
- Institute of Anatomy and Cell Biology, University of Freiburg, Freiburg, Germany
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39
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Host L, Anglard P, Romieu P, Thibault C, Dembele D, Aunis D, Zwiller J. Inhibition of histone deacetylases in rats self-administering cocaine regulates lissencephaly gene-1 and reelin gene expression, as revealed by microarray technique. J Neurochem 2010; 113:236-47. [DOI: 10.1111/j.1471-4159.2010.06591.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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40
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Dekimoto H, Terashima T, Katsuyama Y. Dispersion of the neurons expressing layer specific markers in the reeler brain. Dev Growth Differ 2010; 52:181-93. [PMID: 20067496 DOI: 10.1111/j.1440-169x.2009.01153.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Neurons with similar functions including neuronal connectivity and gene expression form discrete condensed structures within the vertebrate brain. This is exemplified within the circuitry formed by the cortical layers and the neuronal nuclei. It is well known that the Reelin protein is required for development of these neuronal structures in rodents and human, but the function of Reelin remains controversial. In this report, we used "layer-specific markers" of the cerebral cortex to carry out detailed observations of spatial distribution of the neuronal subpopulations in the brain of the Reelin deficient mouse, reeler. We observed a spatially dispersed expression of the markers in the reeler cerebral cortex. These markers are expressed also in other laminated and non-laminated structures of brain, in which we observed similar abnormal gene expression. Our observations suggest that neurons within the brain structures (such as the layers and the nuclei), which normally exhibit condensed distribution of marker expressions, loosen their segregation or scatter by a lack of Reelin.
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Affiliation(s)
- Hideyuki Dekimoto
- Division of Anatomy and Neurobiology, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
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41
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Gopal PP, Simonet JC, Shapiro W, Golden JA. Leading process branch instability in Lis1+/- nonradially migrating interneurons. ACTA ACUST UNITED AC 2009; 20:1497-505. [PMID: 19861636 DOI: 10.1093/cercor/bhp211] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mammalian forebrain development requires extensive migration, yet the mechanisms through which migrating neurons sense and respond to guidance cues are not well understood. Similar to the axon growth cone, the leading process and branches of neurons may guide migration, but the cytoskeletal events that regulate branching are unknown. We have previously shown that loss of microtubule-associated protein Lis1 reduces branching during migration compared with wild-type neurons. Using time-lapse imaging of Lis1(+/-) and Lis1(+/+) cells migrating from medial ganglionic eminence explant cultures, we show that the branching defect is not due to a failure to initiate branches but a defect in the stabilization of new branches. The leading processes of Lis1(+/-) neurons have reduced expression of stabilized, acetylated microtubules compared with Lis1(+/+) neurons. To determine whether Lis1 modulates branch stability through its role as the noncatalytic beta regulatory subunit of platelet-activating factor (PAF) acetylhydrolase 1b, exogenous PAF was applied to wild-type cells. Excess PAF added to wild-type neurons phenocopies the branch instability observed in Lis1(+/-) neurons, and a PAF antagonist rescues leading process branching in Lis1(+/-) neurons. These data highlight a role for Lis1, acting through the PAF pathway, in leading process branching and microtubule stabilization.
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Affiliation(s)
- Pallavi P Gopal
- University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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42
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Abstract
Genetic microcephaly and lissencephaly are 2 of the most common brain malformations. Each of them is a heterogeneous group of disorders caused by mutations of many different genes. They are a significant cause of neurological morbidity in children worldwide, responsible for many cases of mental retardation, cerebral palsy, and epilepsy. Recent advances in molecular genetics have led to the identification of several genes causing these disorders, and thus accurate molecular diagnosis and improved genetic counseling has become available for many patients and their families. More recently identified genes include STIL, causing primary autosomal recessive microcephaly (microcephaly vera), and TUBA1A, causing lissencephaly. Numerous other disease genes are likely still to be identified. Functional studies of genes that cause microcephaly and lissencephaly have provided valuable insight into the molecular mechanisms of human brain development.
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Affiliation(s)
- Ganeshwaran H Mochida
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA.
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43
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Molecular regulation of neuronal migration during neocortical development. Mol Cell Neurosci 2009; 42:11-22. [PMID: 19523518 DOI: 10.1016/j.mcn.2009.06.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 06/03/2009] [Indexed: 11/21/2022] Open
Abstract
Neocortex, a distinct six-layered neural structure, is one of the most exquisite nerve tissues in the human body. Proper assembly of neocortex requires precise regulation of neuronal migration and abnormalities can result in severe neurological diseases. Three major types of neuronal migration have been implicated in corticogenesis: radial migration of excitatory neuron precursors and tangential migration of interneurons as well as Cajal-Retzius cells. In the past several years, significant progress has been made in understanding how these parallel events are regulated and coordinated during corticogenesis. New insights have been gained into regulation of radial neuron migration by the well-known Reelin signal. New pathways have also been identified that regulate radial as well as tangential migration. Equally important, better understandings have been obtained on the cellular and molecular mechanics of cell migration by both projection neurons and interneurons. These findings have not only enhanced our understanding of normal neuron migration but also revealed insights into the etiologies of several neurological diseases where these processes go awry.
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Abstract
PURPOSE OF REVIEW Over the past few years, apolipoprotein E (ApoE) receptors, also known as LDL receptor-related proteins, have distinguished themselves as functionally diverse signaling receptors with pivotal roles not only in the vascular system but also in the nervous system and during development. RECENT FINDINGS The expanding roles of ApoE receptors for cellular signal transduction at the same time transcend and integrate their lipid transport roles into a larger biological and clinical context. ApoE receptors are essential for the development of the nervous system, the regulation of synaptic plasticity, neuroprotection and the innervation of the muscle. They also regulate the metabolism of the amyloid precursor protein on multiple levels, implicating them in the pathogenesis of Alzheimer's disease. SUMMARY ApoE, a common ligand for all members of the evolutionarily ancient LDL receptor gene family, is the major genetic modifier of the age of onset of Alzheimer's disease. The underlying molecular mechanisms remain shrouded in mystery, but the numerous critical functions of ApoE receptors within and outside the nervous system that have recently emerged make it likely that these multifunctional signal modulators participate in Alzheimer's disease pathogenesis. This review attempts to summarize the most recent and relevant findings in this area.
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Affiliation(s)
- Joachim Herz
- Department of Molecular Genetics, UT Southwestern, Dallas, Texas 75390-9046, USA.
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Zhang G, Assadi AH, Roceri M, Clark GD, D'Arcangelo G. Differential interaction of the Pafah1b alpha subunits with the Reelin transducer Dab1. Brain Res 2009; 1267:1-8. [PMID: 19272360 DOI: 10.1016/j.brainres.2009.02.059] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 02/19/2009] [Accepted: 02/19/2009] [Indexed: 02/04/2023]
Abstract
The Reelin signaling pathway controls radial neuronal migration and maturation in the developing brain. The platelet activating factor (PAF) acetyl hydrolase 1b (Pafah1b) complex is also involved in multiple aspects of brain development. We previously showed that the Reelin pathway and the Pafah1b complex interact genetically and biochemically. Lis1, the regulatory subunit of Pafah1b interacts with phosphoDab1, an essential mediator of Reelin signaling. Compound mutants carrying mutations in both, the Reelin pathway and Lis1 exhibit hydrocephalus, a phenotype that is suppressed by mutations in the gene encoding the Alpha2 subunit of Pafah1b. This subunit, like the Alpha1 catalytic subunit of Pafah1b also binds the Reelin receptor VLDLR. Here we investigated the molecular interactions of the Pafah1b catalytic subunits with Dab1. We found that Alpha2 coprecipitates with Dab1 from brain extracts of normal and reeler mutant mice lacking Reelin, and from cell-free extracts containing normal or a phosphorylation mutant form of Dab1, suggesting that Dab1 phosphorylation is not necessary for binding to Alpha2. This interaction is specific for Alpha2 and not Alpha1, and depends on a unique tyrosine residue of Alpha2. Biochemical assays using mutant mice lacking Alpha2 further demonstrated that this subunit is not required for Reelin-induced Dab1 phosphorylation. However, increasing amounts of Alpha2 in a cell-free system disrupted the formation of Dab1-Lis1 complexes without affecting the association of Dab1 with VLDLR. Our data suggest that the Alpha2 subunit may play a modulatory role in the formation of protein complexes that affect brain development and hydrocephalus.
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Affiliation(s)
- Guangcheng Zhang
- The Cain Foundation Laboratories, Texas Children's Hospital, Houston, TX 77030, USA
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Assadi AH, Zhang G, McNeil R, Clark GD, D'Arcangelo G. Pafah1b2 mutations suppress the development of hydrocephalus in compound Pafah1b1; Reln and Pafah1b1; Dab1 mutant mice. Neurosci Lett 2008; 439:100-5. [PMID: 18514414 DOI: 10.1016/j.neulet.2008.04.096] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 04/21/2008] [Accepted: 04/22/2008] [Indexed: 11/29/2022]
Abstract
Reelin, an extracellular protein that signals through the Dab1 adapter protein, and Lis1 regulate neuronal migration and cellular layer formation in the brain. Loss of Reelin and reduction in Lis1 activity in mice or humans results in the disorganization of cortical structures. Lis1, the product of the Pafah1b1 gene associates with Alpha1 (the product of the Pafah1b3 gene) and Alpha2 (the product of the Pafah1b2 gene) to form the Pafah1b heterotrimeric complex. This complex interacts biochemically and genetically with the Reelin pathway, however, the role of Alpha1 and Alpha2 in brain development is poorly understood. We previously demonstrated that compound mutations of Pafah1b1 with genes in Reelin pathway result in layering defects and the appearance of hydrocephalus in double mutant mice. Here, we generate triple mouse mutants to investigate the effect of individual Pafah1b Alpha subunits on cellular layer formation and hydrocephalus. We found that Pafah1b3 mutations exacerbate the layering defects, whereas Pafah1b2 mutations strongly suppress the hydrocephalus phenotype of compound mutant mice. The data indicate that the two Pafah1b Alpha subunits have profoundly different effects on brain development and interact in a significantly different manner with the Reelin signaling pathway.
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Affiliation(s)
- Amir H Assadi
- The Cain Foundation Laboratories, Texas Children's Hospital, Houston, TX 77030, USA
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Cerebellar hypoplasia, with quadrupedal locomotion, caused by mutations in the very low-density lipoprotein receptor gene. Eur J Hum Genet 2008; 16:1070-4. [PMID: 18364738 DOI: 10.1038/ejhg.2008.73] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The cerebellum is the primary motor coordination centre of the central nervous system. Lesions or congenital defects of the cerebellum cause incoordination of the muscles resulting in irregular gait and falling. Recently, we reported a large family with cerebellum hypoplasia and quadrupedal locomotion as a recessive trait, which we mapped to chromosome 17p13. We identified one additional family with the same condition and mapped the underlying gene to a 14-cM interval on chromosome 9ptel using a genome-wide linkage approach. Sequencing of candidate genes identified a homozygous frameshift mutation in the very low-density lipoprotein receptor (VLDLR) gene in all affected individuals. The association of cerebellar hypoplasia with mutations in VLDLR has been reported previously in the Hutterite population and in a family from Iran. However, quadrupedal locomotion was never observed indicating that environmental factors play a major role in the pathogenesis of this form of locomotion.
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Suzuki K, Nakamura K, Iwata Y, Sekine Y, Kawai M, Sugihara G, Tsuchiya KJ, Suda S, Matsuzaki H, Takei N, Hashimoto K, Mori N. Decreased expression of reelin receptor VLDLR in peripheral lymphocytes of drug-naive schizophrenic patients. Schizophr Res 2008; 98:148-56. [PMID: 17936586 DOI: 10.1016/j.schres.2007.09.029] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 09/12/2007] [Accepted: 09/18/2007] [Indexed: 12/19/2022]
Abstract
Reelin, a secretory protease that plays major roles in neurodevelopment and synaptic plasticity, may also play a role in the pathogenesis of schizophrenia. The present study was undertaken to examine whether the expression of two receptors for reelin, very low-density lipoprotein receptor (VLDLR) and apolipoprotein E receptor type 2 (ApoER2), were abnormal in peripheral blood lymphocytes of schizophrenic patients. In this study, we measured the mRNA levels of VLDLR and ApoER2 in blood lymphocytes from patients with schizophrenia (drug-naive patients (n=20) and medicated patients (n=20)) and age-and gender-matched healthy controls (n=40) using quantitative real-time RT-PCR. Furthermore, we examined the correlation between mRNA levels and clinical variables in patients. Levels of VLDLR mRNA in drug-naive, unmedicated patients with schizophrenia were significantly lower than those of controls. In contrast, levels of ApoER2 mRNA in drug-naive patients did not differ from those of controls, although the levels of ApoER2 mRNA in medicated patients were significantly lower than those of controls. Interestingly, levels of VLDLR mRNA in drug-naive patients showed significant increases with respect to baseline after six months of antipsychotic treatment, whereas levels of ApoER2 mRNA were significantly lower than baseline after six months of treatment. In all patients, there was a negative correlation between VLDLR mRNA levels and the severity of clinical symptoms. Our findings suggest that peripheral VLDLR mRNA levels may serve as a reliable peripheral biological marker of schizophrenia, and that the reelin-VLDLR/ApoER2 signaling pathway plays a role in the pathophysiology of schizophrenia.
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Affiliation(s)
- Katsuaki Suzuki
- Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Kerjan G, Gleeson JG. Genetic mechanisms underlying abnormal neuronal migration in classical lissencephaly. Trends Genet 2007; 23:623-30. [PMID: 17997185 DOI: 10.1016/j.tig.2007.09.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 09/18/2007] [Accepted: 09/18/2007] [Indexed: 11/26/2022]
Abstract
Classical lissencephaly is a human developmental brain disorder characterized by a paucity of cortical gyration and thickening of the cortical gray matter, leading to severe epilepsy and mental retardation. Loss-of-function mutations in the microtubule-associated protein encoding genes, PAFAH1B1 (encoding the protein LIS1), DCX and TUBA1A have been implicated in the pathogenesis of the condition. Animal models are required to understand the basis of this disease, which is a challenge, given that mice normally have a smooth cortex. Recent advances toward this goal have come from stepwise reduction in gene function, deletion of redundant genes and acute gene inactivation using short hairpin RNA (shRNA). These approaches have implicated genes that regulate the microtubule cytoskeleton during neuronal division, migration and maturation.
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Affiliation(s)
- Geraldine Kerjan
- Neurogenetics Laboratory, Department of Neurosciences, LBR3A16, UCSD School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093-0691, USA
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