1
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Wang Y, Wang B, Cao W, Xu X. TGF-β-activated circRYK drives glioblastoma progression by increasing VLDLR mRNA expression and stability in a ceRNA- and RBP-dependent manner. J Exp Clin Cancer Res 2024; 43:73. [PMID: 38454465 PMCID: PMC10921701 DOI: 10.1186/s13046-024-03000-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Accepted: 03/01/2024] [Indexed: 03/09/2024] Open
Abstract
BACKGROUND The TGF-β signalling pathway is intricately associated with the progression of glioblastoma (GBM). The objective of this study was to examine the role of circRNAs in the TGF-β signalling pathway. METHODS In our research, we used transcriptome analysis to search for circRNAs that were activated by TGF-β. After confirming the expression pattern of the selected circRYK, we carried out in vitro and in vivo cell function assays. The underlying mechanisms were analysed via RNA pull-down, luciferase reporter, and RNA immunoprecipitation assays. RESULTS CircRYK expression was markedly elevated in GBM, and this phenotype was strongly associated with a poor prognosis. Functionally, circRYK promotes epithelial-mesenchymal transition and GSC maintenance in GBM. Mechanistically, circRYK sponges miR-330-5p and promotes the expression of the oncogene VLDLR. In addition, circRYK could enhance the stability of VLDLR mRNA via the RNA-binding protein HuR. CONCLUSION Our findings show that TGF-β promotes epithelial-mesenchymal transition and GSC maintenance in GBM through the circRYK-VLDLR axis, which may provide a new therapeutic target for the treatment of GBM.
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Affiliation(s)
- Yuhang Wang
- Department of Neurosurgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, 210000, China
| | - Binbin Wang
- Department of Neurosurgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, 210000, China
| | - Wenping Cao
- Department of Neurosurgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, 210000, China.
| | - Xiupeng Xu
- Department of Neurosurgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, 210000, China.
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2
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Iwasaki T, Watanabe R, Zhang H, Hashimoto M, Morinobu A, Matsuda F. Identification of the VLDLR locus associated with giant cell arteritis and the possible causal role of low-density lipoprotein cholesterol in its pathogenesis. Rheumatology (Oxford) 2024:keae075. [PMID: 38317496 DOI: 10.1093/rheumatology/keae075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 01/11/2024] [Accepted: 01/19/2024] [Indexed: 02/07/2024] Open
Abstract
OBJECTIVES To elucidate the association between genetic variants and the risk of giant cell arteritis (GCA) via large-scale genome-wide association studies (GWAS). In addition, to assess the causal effect of a specific molecule by employing the obtained GWAS results as genetic epidemiological tools. METHODS We applied additional variant quality control to the publicly available GWAS results from the biobank of the United Kingdom (UKBB) and Finnish (FinnGen), which comprised 532 cases vs 408 565 controls and 884 cases vs 332 115 controls, respectively. We further meta-analyzed these two sets of results. We performed two-sample Mendelian randomization (MR) to test the causal effect of low-density lipoprotein (LDL) cholesterol on the risk of GCA. RESULTS The MHC class II region showed significant associations in UKBB, FinnGen, and the meta-analysis. The VLDLR region was associated with GCA risk in the meta-analysis. The T allele of rs7044155 increased the expression of VLDLR, decreased the LDL cholesterol level, and decreased the disease risk. The subsequent MR results indicated that a 1-standard deviation increase in LDL cholesterol was associated with an increased risk of GCA (odds ratio [OR] 1.21, 95% confidence interval [CI] 1.01-1.45; p = 0.04). CONCLUSIONS Our study identified associations between GCA risk and the MHC class II and VLDLR regions. Moreover, LDL cholesterol was suggested to have a causal effect on the risk of developing GCA.
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Affiliation(s)
- Takeshi Iwasaki
- Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Rheumatology and Clinical Immunology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Ryu Watanabe
- Department of Clinical Immunology, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Hui Zhang
- Department of Rheumatology and Clinical Immunology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Motomu Hashimoto
- Department of Clinical Immunology, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Akio Morinobu
- Department of Rheumatology and Clinical Immunology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Fumihiko Matsuda
- Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
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3
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Bristow CL. Silencing Very-Low-Density Lipoprotein Receptor Reveals Alpha-1 Antitrypsin Role in HIV Infectivity. Methods Mol Biol 2024; 2750:175-184. [PMID: 38108977 DOI: 10.1007/978-1-0716-3605-3_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Here we describe methods for investigating alpha-1 antitrypsin (AAT) and very-low-density lipoprotein receptor (VLDLR) interactions with infectious and non-infectious HIV-1 virions. Using silencing RNA to transiently block expression of VLDLR and the receptor-associated protein (RAP) to continuously block VLDLR activity, AAT is demonstrated to participate with VLDLR during internalization and infectivity of HIV-1 virions.
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Affiliation(s)
- Cynthia L Bristow
- Alpha-1 Biologics, Long Island High Technology Incubator, Stony Brook University, Stony Brook, NY, USA.
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4
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Gupta T, Kaur M, Gupta M, Singla N, Kharbanda PS, Bansal YS, Radotra BD, Gupta SK. Analysis of distribution and localization of proteins of the reelin signalling pathway in mesial temporal lobe epilepsy. Int J Neurosci 2023:1-15. [PMID: 38060511 DOI: 10.1080/00207454.2023.2292957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 12/02/2023] [Indexed: 12/17/2023]
Abstract
INTRODUCTION Granule cell dispersion (GCD) is pathognomonic of hippocampal sclerosis seen in the mesial temporal lobe epilepsy (MTLE). Current animal studies indicate deficiency of Reelin is associated with abnormal granule cell migration leading to GCD. The present study aimed to evaluate complete Reelin signalling pathway to assess whether Reelin deficiency is related to MTLE. MATERIALS AND METHODS Hippocampal sclerosis was confirmed by H and E stain. To explore the amount and cellular location of the Reelin cascade molecules, the hippocampal tissues from MTLE surgery and controls (n = 15 each) were studied using Immuno-histochemistry (IHC). Additionally, confocal imaging was used to validate the IHC findings by co-localization of different proteins. Quantification of IHC images was performed using histo-score and confocal images by Image J software. RESULTS Immune expression of active Reelin was significantly reduced in patients. Reelin receptors were deranged, apolipoprotein E receptor 2 was increased while very low-density lipoprotein receptor was reduced. Disabled-1, a downstream molecule was significantly reduced in MTLE. Its ultimate target, cofilin was thus disinhibited and expressed more in MTLE. Reelin cleaving protease, matrix metalloprotease-9 (MMP-9) and MMP-9 inhibitor, tissue inhibitor of matrix protease-1, showed reduced expression in extracellular matrix. Semi-quantification of immunohistochemistry was done using Histo (H) score. H score of Reelin in diseased patients was 15 against 125 for control patients. These results were validated by confocal fluorescence microscopy. CONCLUSIONS Reelin signalling cascade was deranged in chronic MTLE. Pharmacological manipulation of Reelin cascade can be done at various levels and it may provide novel treatment options for MTLE.
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Affiliation(s)
- Tulika Gupta
- Department of Anatomy, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Mandeep Kaur
- Department of Anatomy, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Mili Gupta
- Department of Biochemistry, Dr. Harvansh Singh Judge Institute of Dental Sciences and Hospital, Panjab University, Chandigarh, India
| | - Navneet Singla
- Department of Neurosurgery, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Parampreet S Kharbanda
- Department of Neurology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Yogender S Bansal
- Department of Forensic Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - B D Radotra
- Department of Histopathology Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - S K Gupta
- Department of Neurosurgery, Post Graduate Institute of Medical Education and Research, Chandigarh, India
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5
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Cao D, Ma B, Cao Z, Zhang X, Xiang Y. Structure of Semliki Forest virus in complex with its receptor VLDLR. Cell 2023; 186:2208-2218.e15. [PMID: 37098345 DOI: 10.1016/j.cell.2023.03.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 01/22/2023] [Accepted: 03/28/2023] [Indexed: 04/27/2023]
Abstract
Semliki Forest virus (SFV) is an alphavirus that uses the very-low-density lipoprotein receptor (VLDLR) as a receptor during infection of its vertebrate hosts and insect vectors. Herein, we used cryoelectron microscopy to study the structure of SFV in complex with VLDLR. We found that VLDLR binds multiple E1-DIII sites of SFV through its membrane-distal LDLR class A (LA) repeats. Among the LA repeats of the VLDLR, LA3 has the best binding affinity to SFV. The high-resolution structure shows that LA3 binds SFV E1-DIII through a small surface area of 378 Å2, with the main interactions at the interface involving salt bridges. Compared with the binding of single LA3s, consecutive LA repeats around LA3 promote synergistic binding to SFV, during which the LAs undergo a rotation, allowing simultaneous key interactions at multiple E1-DIII sites on the virion and enabling the binding of VLDLRs from divergent host species to SFV.
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Affiliation(s)
- Duanfang Cao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Bingting Ma
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Ziyi Cao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences (CAS), Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinzheng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences (CAS), Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Ye Xiang
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing 100084, China.
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6
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Yang M, Zhan Y, Hou Z, Wang C, Fan W, Guo T, Li Z, Fang L, Lv S, Li S, Gu C, Ye M, Qin H, Liu Q, Cui X. VLDLR disturbs quiescence of breast cancer stem cells in a ligand-independent function. Front Oncol 2022; 12:887035. [PMID: 36568166 PMCID: PMC9767959 DOI: 10.3389/fonc.2022.887035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 11/11/2022] [Indexed: 12/12/2022] Open
Abstract
Breast cancer stem cells are responsible for cancer initiation, progression, and drug resistance. However, effective targeting strategies against the cell subpopulation are still limited. Here, we unveil two splice variants of very-low-density lipoprotein receptor, VLDLR-I and -II, which are highly expressed in breast cancer stem cells. In breast cancer cells, VLDLR silencing suppresses sphere formation abilities in vitro and tumor growth in vivo. We find that VLDLR knockdown induces transition from self-renewal to quiescence. Surprisingly, ligand-binding activity is not involved in the cancer-promoting functions of VLDLR-I and -II. Proteomic analysis reveals that citrate cycle and ribosome biogenesis-related proteins are upregulated in VLDLR-I and -II overexpressed cells, suggesting that VLDLR dysregulation is associated with metabolic and anabolic regulation. Moreover, high expression of VLDLR in breast cancer tissues correlates with poor prognosis of patients. Collectively, these findings indicate that VLDLR may be an important therapeutic target for breast cancer treatment.
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Affiliation(s)
- Mengying Yang
- The First Affiliated Hospital, Dalian Medical University, Dalian, China,Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian, China,State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-sen University, Guangzhou, China
| | - Yajing Zhan
- Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian, China
| | - Zhijie Hou
- Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian, China
| | - Chunli Wang
- Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian, China
| | - Wenjun Fan
- Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian, China
| | - Tao Guo
- The First Affiliated Hospital, Dalian Medical University, Dalian, China
| | - Zhuoshi Li
- The First Affiliated Hospital, Dalian Medical University, Dalian, China
| | - Lei Fang
- The First Affiliated Hospital, Dalian Medical University, Dalian, China
| | - Shasha Lv
- Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian, China
| | - Sisi Li
- Department of Pathology, Harbin Medical University Cancer Hospital, Harbin, China
| | - Chundong Gu
- The First Affiliated Hospital, Dalian Medical University, Dalian, China
| | - Mingliang Ye
- Chinese Academy of Sciences (CAS) Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, China
| | - Hongqiang Qin
- Chinese Academy of Sciences (CAS) Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, China,*Correspondence: Xiaonan Cui, ; Quentin Liu, ; Hongqiang Qin,
| | - Quentin Liu
- Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian, China,State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-sen University, Guangzhou, China,*Correspondence: Xiaonan Cui, ; Quentin Liu, ; Hongqiang Qin,
| | - Xiaonan Cui
- The First Affiliated Hospital, Dalian Medical University, Dalian, China,*Correspondence: Xiaonan Cui, ; Quentin Liu, ; Hongqiang Qin,
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7
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Calvier L, Herz J, Hansmann G. Interplay of Low-Density Lipoprotein Receptors, LRPs, and Lipoproteins in Pulmonary Hypertension. JACC Basic Transl Sci 2022; 7:164-180. [PMID: 35257044 PMCID: PMC8897182 DOI: 10.1016/j.jacbts.2021.09.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/17/2021] [Accepted: 09/18/2021] [Indexed: 12/21/2022]
Abstract
LDLR regulates oxidized LDL level, which is increased in lung and blood from PAH patients. LRP1 preserving vascular homeostasis is decreased in PAH patients. LRP5/6 regulating Wnt signaling is upregulated in PH. The LRP8 (aka ApoER2) ligand ApoE protects from PAH.
The low-density lipoprotein receptor (LDLR) gene family includes LDLR, very LDLR, and LDL receptor–related proteins (LRPs) such as LRP1, LRP1b (aka LRP-DIT), LRP2 (aka megalin), LRP4, and LRP5/6, and LRP8 (aka ApoER2). LDLR family members constitute a class of closely related multifunctional, transmembrane receptors, with diverse functions, from embryonic development to cancer, lipid metabolism, and cardiovascular homeostasis. While LDLR family members have been studied extensively in the systemic circulation in the context of atherosclerosis, their roles in pulmonary arterial hypertension (PAH) are understudied and largely unknown. Endothelial dysfunction, tissue infiltration of monocytes, and proliferation of pulmonary artery smooth muscle cells are hallmarks of PAH, leading to vascular remodeling, obliteration, increased pulmonary vascular resistance, heart failure, and death. LDLR family members are entangled with the aforementioned detrimental processes by controlling many pathways that are dysregulated in PAH; these include lipid metabolism and oxidation, but also platelet-derived growth factor, transforming growth factor β1, Wnt, apolipoprotein E, bone morpohogenetic proteins, and peroxisome proliferator-activated receptor gamma. In this paper, we discuss the current knowledge on LDLR family members in PAH. We also review mechanisms and drugs discovered in biological contexts and diseases other than PAH that are likely very relevant in the hypertensive pulmonary vasculature and the future care of patients with PAH or other chronic, progressive, debilitating cardiovascular diseases.
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Key Words
- ApoE, apolipoprotein E
- Apoer2
- BMP
- BMPR, bone morphogenetic protein receptor
- BMPR2
- COPD, chronic obstructive pulmonary disease
- CTGF, connective tissue growth factor
- HDL, high-density lipoprotein
- KO, knockout
- LDL receptor related protein
- LDL, low-density lipoprotein
- LDLR
- LDLR, low-density lipoprotein receptor
- LRP
- LRP, low-density lipoprotein receptor–related protein
- LRP1
- LRP1B
- LRP2
- LRP4
- LRP5
- LRP6
- LRP8
- MEgf7
- Mesd, mesoderm development
- PAH
- PAH, pulmonary arterial hypertension
- PASMC, pulmonary artery smooth muscle cell
- PDGF
- PDGFR-β, platelet-derived growth factor receptor-β
- PH, pulmonary hypertension
- PPARγ
- PPARγ, peroxisome proliferator-activated receptor gamma
- PVD
- RV, right ventricle/ventricular
- RVHF
- RVSP, right ventricular systolic pressure
- TGF-β1
- TGF-β1, transforming growth factor β1
- TGFBR, transforming growth factor β1 receptor
- TNF, tumor necrosis factor receptor
- VLDLR
- VLDLR, very low density lipoprotein receptor
- VSMC, vascular smooth muscle cell
- Wnt
- apolipoprotein E receptor 2
- endothelial cell
- gp330
- low-density lipoprotein receptor
- mRNA, messenger RNA
- megalin
- monocyte
- multiple epidermal growth factor-like domains 7
- pulmonary arterial hypertension
- pulmonary vascular disease
- right ventricle heart failure
- smooth muscle cell
- very low density lipoprotein receptor
- β-catenin
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Affiliation(s)
- Laurent Calvier
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Center for Translational Neurodegeneration Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Joachim Herz
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Center for Translational Neurodegeneration Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Georg Hansmann
- Department of Pediatric Cardiology and Critical Care, Hannover Medical School, Hannover, Germany.,Pulmonary Vascular Research Center, Hannover Medical School, Hannover, Germany
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8
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Jin BR, Lee M, An HJ. Nodakenin represses obesity and its complications via the inhibition of the VLDLR signalling pathway in vivo and in vitro. Cell Prolif 2021; 54:e13083. [PMID: 34165214 PMCID: PMC8349651 DOI: 10.1111/cpr.13083] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/22/2021] [Accepted: 05/29/2021] [Indexed: 12/11/2022] Open
Abstract
Objectives Nodakenin (NK) is a coumarin glucoside that is found in the roots of Angelicae gigas. A limited number of studies have been conducted on the pharmacological activities of NK. Although NK is an important natural resource having anti‐inflammatory and antioxidant effects, no investigation has been conducted to examine the effects of NK on obesity and obesity‐induced inflammation. Materials and Methods The present study investigated the therapeutic effects of NK treatment on obesity and its complications, and its mechanism of action using differentiated 3T3‐L1 adipocytes and high‐fat diet (HFD)‐induced obese mice. Oil red O staining, western blot assay, qRT‐PCR assay, siRNA transfection, enzyme‐linked immunosorbent assay, H&E staining, immunohistochemistry, molecular docking and immunofluorescence staining were utilized. Results Treatment with NK demonstrated anti‐adipogenesis effects via the regulation of adipogenic transcription factors and genes associated with triglyceride synthesis in differentiated 3T3‐L1 adipocytes. Compared with the control group, the group administered NK showed a suppression in weight gain, dyslipidaemia and the development of fatty liver in HFD‐induced obese mice. In addition, NK administration inhibited adipogenic differentiation and obesity‐induced inflammation and oxidative stress via the suppression of the VLDLR and MEK/ERK1/2 pathways. This is the first study that has documented the interaction between NK and VLDLR structure. Conclusion These results demonstrate the potential of NK as a natural product‐based therapeutic candidate for the treatment of obesity and its complications by targeting adipogenesis and adipose tissue inflammation‐associated markers.
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Affiliation(s)
- Bo-Ram Jin
- Department of Pharmacology, College of Korean Medicine, Sangji University, Wonju, Korea
| | - Minho Lee
- Department of Life Science, Dongguk University-Seoul, Goyang-si, Korea
| | - Hyo-Jin An
- Department of Pharmacology, College of Korean Medicine, Sangji University, Wonju, Korea
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9
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Turk LS, Kuang X, Dal Pozzo V, Patel K, Chen M, Huynh K, Currie MJ, Mitchell D, Dobson RCJ, D'Arcangelo G, Dai W, Comoletti D. The structure-function relationship of a signaling-competent, dimeric Reelin fragment. Structure 2021; 29:1156-1170.e6. [PMID: 34089653 DOI: 10.1016/j.str.2021.05.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/26/2021] [Accepted: 05/14/2021] [Indexed: 01/21/2023]
Abstract
Reelin operates through canonical and non-canonical pathways that mediate several aspects of brain development and function. Reelin's dimeric central fragment (CF), generated through proteolytic cleavage, is required for the lipoprotein-receptor-dependent canonical pathway activation. Here, we analyze the signaling properties of a variety of Reelin fragments and measure the differential binding affinities of monomeric and dimeric CF fragments to lipoprotein receptors to investigate the mode of canonical signal activation. We also present the cryoelectron tomography-solved dimeric structure of Reelin CF and support it using several other biophysical techniques. Our findings suggest that Reelin CF forms a covalent parallel dimer with some degree of flexibility between the two protein chains. As a result of this conformation, Reelin binds to lipoprotein receptors in a manner inaccessible to its monomeric form and is capable of stimulating canonical pathway signaling.
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Affiliation(s)
- Liam S Turk
- Child Health Institute of New Jersey, New Brunswick, NJ 08901, USA; Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA; School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Xuyuan Kuang
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Department of Hyperbaric Oxygen, Central South University, Changsha, Hunan Province, China
| | - Valentina Dal Pozzo
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Khush Patel
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Muyuan Chen
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kevin Huynh
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Michael J Currie
- Biomolecular Interactions Centre and School of Biological Sciences, University of Canterbury, Christchurch 8041, New Zealand
| | - Daniel Mitchell
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Renwick C J Dobson
- Biomolecular Interactions Centre and School of Biological Sciences, University of Canterbury, Christchurch 8041, New Zealand; Bio21 Molecular Science and Biotechnology Institute, Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Gabriella D'Arcangelo
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Wei Dai
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
| | - Davide Comoletti
- Child Health Institute of New Jersey, New Brunswick, NJ 08901, USA; Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA; School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand.
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10
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Gao S, Li R, Heng N, Chen Y, Wang L, Li Z, Guo Y, Sheng X, Wang X, Xing K, Ni H, Qi X. Effects of dietary supplementation of natural astaxanthin from Haematococcus pluvialis on antioxidant capacity, lipid metabolism, and accumulation in the egg yolk of laying hens. Poult Sci 2020; 99:5874-5882. [PMID: 33142505 PMCID: PMC7647864 DOI: 10.1016/j.psj.2020.08.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 07/18/2020] [Accepted: 08/07/2020] [Indexed: 01/21/2023] Open
Abstract
The present study evaluated the effects of natural astaxanthin (ASTA) from Haematococcus pluvialis on the antioxidant capacity, lipid metabolism, and ASTA accumulation in the egg yolk of laying hens. Hy-Line Brown layers (n = 288, 50 wk old) were randomly assigned to 1 of 4 dietary treatment groups. Each group had 6 replicates of 12 hens each. All birds were given a corn-soybean meal-based diet containing 0, 25, 50, or 100 mg/kg ASTA for 6 wk. The results showed that the total antioxidant capacity, superoxide dismutase level, and glutathione peroxidase level in the plasma, livers, and egg yolks were significantly increased in the ASTA groups compared with those of the control group (P < 0.05), whereas the content of malondialdehyde linearly decreased (P < 0.05). The plasma levels of high-density and very-low-density lipoprotein cholesterol in the ASTA groups were significantly higher than those in the control group (P < 0.05). In addition, ASTA supplementation decreased low-density lipoprotein cholesterol and triglyceride plasma levels (P < 0.05). However, there were no significant differences in the other lipid metabolism parameters among the ASTA-supplemented groups relative to the control group except for an increase in high-density lipoprotein cholesterol in the liver. Compared with the control, dietary ASTA supplementation significantly increased the enrichment of ASTA in egg yolks at the end of week 2, 4, and 6 (P < 0.05). The mRNA expression of scavenger receptor class B type 1 (SCARB1) and very-low-density lipoprotein receptor (VLDLR) in the ASTA groups was markedly higher (P < 0.05) than that in the control group in the liver and ovaries, respectively. In conclusion, these results suggest that dietary ASTA enhances the antioxidant capacity and regulates lipid metabolism in laying hens. ASTA enrichment in egg yolks may be closely related to the upregulation of SCARB1 and VLDLR gene expression.
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Affiliation(s)
- Shan Gao
- Animal Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Runhua Li
- Animal Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Nuo Heng
- Animal Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Yu Chen
- Department of Livestock and Poultry Products Testing, Beijing General Station of Animal Husbandry, Beijing 100107, China
| | - Liang Wang
- Department of Livestock and Poultry Products Testing, Beijing General Station of Animal Husbandry, Beijing 100107, China
| | - Zheng Li
- Feed Analysis Lab, Beijing Institute of Feed Control, Beijing 100012, China
| | - Yong Guo
- Animal Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Xihui Sheng
- Animal Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Xiangguo Wang
- Animal Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Kai Xing
- Animal Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Hemin Ni
- Animal Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Xiaolong Qi
- Animal Science and Technology College, Beijing University of Agriculture, Beijing 102206, China.
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11
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Barroso E, Rodríguez-Rodríguez R, Zarei M, Pizarro-Degado J, Planavila A, Palomer X, Villarroya F, Vázquez-Carrera M. SIRT3 deficiency exacerbates fatty liver by attenuating the HIF1α-LIPIN 1 pathway and increasing CD36 through Nrf2. Cell Commun Signal 2020; 18:147. [PMID: 32912335 PMCID: PMC7488148 DOI: 10.1186/s12964-020-00640-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 08/07/2020] [Indexed: 12/15/2022] Open
Abstract
Background Deficiency of mitochondrial sirtuin 3 (SIRT3), a NAD+-dependent protein deacetylase that maintains redox status and lipid homeostasis, contributes to hepatic steatosis. In this study, we investigated additional mechanisms that might play a role in aggravating hepatic steatosis in Sirt3-deficient mice fed a high-fat diet (HFD). Methods Studies were conducted in wild-type (WT) and Sirt3−/− mice fed a standard diet or a HFD and in SIRT3-knockdown human Huh-7 hepatoma cells. Results Sirt3−/− mice fed a HFD presented exacerbated hepatic steatosis that was accompanied by decreased expression and DNA-binding activity of peroxisome proliferator-activated receptor (PPAR) α and of several of its target genes involved in fatty acid oxidation, compared to WT mice fed the HFD. Interestingly, Sirt3 deficiency in liver and its knockdown in Huh-7 cells resulted in upregulation of the nuclear levels of LIPIN1, a PPARα co-activator, and of the protein that controls its levels and localization, hypoxia-inducible factor 1α (HIF-1α). These changes were prevented by lipid exposure through a mechanism that might involve a decrease in succinate levels. Finally, Sirt3−/− mice fed the HFD showed increased levels of some proteins involved in lipid uptake, such as CD36 and the VLDL receptor. The upregulation in CD36 was confirmed in Huh-7 cells treated with a SIRT3 inhibitor or transfected with SIRT3 siRNA and incubated with palmitate, an effect that was prevented by the Nrf2 inhibitor ML385. Conclusion These findings demonstrate new mechanisms by which Sirt3 deficiency contributes to hepatic steatosis. Video abstract
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Affiliation(s)
- Emma Barroso
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain.,Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain.,Research Institute-Hospital Sant Joan de Déu, L'Hospitalet de Llobregat, Spain
| | - Rosalía Rodríguez-Rodríguez
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain.,Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain.,Research Institute-Hospital Sant Joan de Déu, L'Hospitalet de Llobregat, Spain
| | - Mohammad Zarei
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain.,Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain.,Research Institute-Hospital Sant Joan de Déu, L'Hospitalet de Llobregat, Spain
| | - Javier Pizarro-Degado
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain.,Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain.,Research Institute-Hospital Sant Joan de Déu, L'Hospitalet de Llobregat, Spain
| | - Anna Planavila
- Research Institute-Hospital Sant Joan de Déu, L'Hospitalet de Llobregat, Spain.,Department of Biochemistry and Molecular Biomedicine and IBUB, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Spanish Biomedical Research Center in Physiopathology of Obesity and Nutrition (CIBEROBN)-Instituto de Salud Carlos III, Barcelona, Spain
| | - Xavier Palomer
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain.,Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain.,Research Institute-Hospital Sant Joan de Déu, L'Hospitalet de Llobregat, Spain
| | - Francesc Villarroya
- Research Institute-Hospital Sant Joan de Déu, L'Hospitalet de Llobregat, Spain.,Department of Biochemistry and Molecular Biomedicine and IBUB, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Spanish Biomedical Research Center in Physiopathology of Obesity and Nutrition (CIBEROBN)-Instituto de Salud Carlos III, Barcelona, Spain
| | - Manuel Vázquez-Carrera
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain. .,Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain. .,Research Institute-Hospital Sant Joan de Déu, L'Hospitalet de Llobregat, Spain. .,Facultat de Farmàcia i Ciències de l'Alimentació, Unitat de Farmacologia, Farmacognòsia i Terapèutica, Av. Joan XXIII 27-31, E-08028, Barcelona, Spain.
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12
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Bestetti I, Castronovo C, Sironi A, Caslini C, Sala C, Rossetti R, Crippa M, Ferrari I, Pistocchi A, Toniolo D, Persani L, Marozzi A, Finelli P. High-resolution array-CGH analysis on 46,XX patients affected by early onset primary ovarian insufficiency discloses new genes involved in ovarian function. Hum Reprod 2020; 34:574-583. [PMID: 30689869 PMCID: PMC6389867 DOI: 10.1093/humrep/dey389] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/23/2018] [Accepted: 12/27/2018] [Indexed: 12/21/2022] Open
Abstract
STUDY QUESTION Can high resolution array-CGH analysis on a cohort of women showing a primary ovarian insufficiency (POI) phenotype in young age identify copy number variants (CNVs) with a deleterious effect on ovarian function? SUMMARY ANSWER This approach has proved effective to clarify the role of CNVs in POI pathogenesis and to better unveil both novel candidate genes and pathogenic mechanisms. WHAT IS KNOWN ALREADY POI describes the progression toward the cessation of ovarian function before the age of 40 years. Genetic causes are highly heterogeneous and despite several genes being associated with ovarian failure, most of genetic basis of POI still needs to be elucidated. STUDY DESIGN, SIZE, DURATION The current study included 67 46,XX patients with early onset POI (<19 years) and 134 control females recruited between 2012 and 2016 at the Medical Cytogenetics and Molecular Genetics Lab, IRCCS Istituto Auxologico Italiano. PARTICIPANTS/MATERIALS, SETTING, METHODS High resolution array-CGH analysis was carried out on POI patients’ DNA. Results of patients and female controls were analyzed to search for rare CNVs. All variants were validated and subjected to a gene content analysis and disease gene prioritization based on the present literature to find out new ovary candidate genes. Case-control study with statistical analysis was carried out to validate our approach and evaluate any ovary CNVs/gene enrichment. Characterization of particular CNVs with molecular and functional studies was performed to assess their pathogenic involvement in POI. MAIN RESULTS AND THE ROLE OF CHANCE We identified 37 ovary-related CNVs involving 44 genes with a role in ovary in 32 patients. All except one of the selected CNVs were not observed in the control group. Possible involvement of the CNVs in POI pathogenesis was further corroborated by a case-control analysis that showed a significant enrichment of ovary-related CNVs/genes in patients (P = 0.0132; P = 0.0126). Disease gene prioritization identified both previously reported POI genes (e.g. BMP15, DIAPH2, CPEB1, BNC1) and new candidates supported by transcript and functional studies, such as TP63 with a role in oocyte genomic integrity and VLDLR which is involved in steroidogenesis. LARGE SCALE DATA ClinVar database (http://www.ncbi.nlm.nih.gov/clinvar/); accession numbers SCV000787656 to SCV000787743. LIMITATIONS, REASONS FOR CAUTION This is a descriptive analysis for almost all of the CNVs identified. Inheritance studies of CNVs in some non-familial sporadic cases was not performed as the parents’ DNA samples were not available. Addionally, RT-qPCR analyses were carried out in few cases as RNA samples were not always available and the genes were not expressed in blood. WIDER IMPLICATIONS OF THE FINDINGS Our array-CGH screening turned out to be efficient in identifying different CNVs possibly implicated in disease onset, thus supporting the extremely wide genetic heterogeneity of POI. Since almost 50% of cases are negative rare ovary-related CNVs, array-CGH together with next generation sequencing might represent the most suitable approach to obtain a comprehensive genetic characterization of POI patients. STUDY FUNDING/COMPETING INTEREST(S) Supported by Italian Ministry of Health grants ‘Ricerca Corrente’ (08C203_2012) and ‘Ricerca Finalizzata’ (GR-2011-02351636, BIOEFFECT) to IRCCS Istituto Auxologico Italiano.
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Affiliation(s)
- I Bestetti
- Istituto Auxologico Italiano, IRCCS, Lab of Medical Cytogenetics and Molecular Genetics, Milan, Italy.,Department of Medical Biotechnology and Translational Medicine, University of Milan, Segrate, Milan, Italy
| | - C Castronovo
- Istituto Auxologico Italiano, IRCCS, Lab of Medical Cytogenetics and Molecular Genetics, Milan, Italy
| | - A Sironi
- Istituto Auxologico Italiano, IRCCS, Lab of Medical Cytogenetics and Molecular Genetics, Milan, Italy.,Department of Medical Biotechnology and Translational Medicine, University of Milan, Segrate, Milan, Italy
| | - C Caslini
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Segrate, Milan, Italy
| | - C Sala
- Division of Genetics and Cell Biology, San Raffaele Research Institute and Vita Salute University, Milan, Italy
| | - R Rossetti
- Istituto Auxologico Italiano, IRCCS, Division of Endocrine and Metabolic Diseases and Lab of Endocrine and Metabolic Research, Milan, Italy
| | - M Crippa
- Istituto Auxologico Italiano, IRCCS, Lab of Medical Cytogenetics and Molecular Genetics, Milan, Italy.,Department of Medical Biotechnology and Translational Medicine, University of Milan, Segrate, Milan, Italy
| | - I Ferrari
- Istituto Auxologico Italiano, IRCCS, Division of Endocrine and Metabolic Diseases and Lab of Endocrine and Metabolic Research, Milan, Italy
| | - A Pistocchi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Segrate, Milan, Italy
| | - D Toniolo
- Division of Genetics and Cell Biology, San Raffaele Research Institute and Vita Salute University, Milan, Italy
| | - L Persani
- Istituto Auxologico Italiano, IRCCS, Division of Endocrine and Metabolic Diseases and Lab of Endocrine and Metabolic Research, Milan, Italy.,Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - A Marozzi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Segrate, Milan, Italy
| | - P Finelli
- Istituto Auxologico Italiano, IRCCS, Lab of Medical Cytogenetics and Molecular Genetics, Milan, Italy.,Department of Medical Biotechnology and Translational Medicine, University of Milan, Segrate, Milan, Italy
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13
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Hirota Y, Nakajima K. VLDLR is not essential for reelin-induced neuronal aggregation but suppresses neuronal invasion into the marginal zone. Development 2020; 147:147/12/dev189936. [PMID: 32540847 DOI: 10.1242/dev.189936] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/26/2020] [Indexed: 11/20/2022]
Abstract
In the developing neocortex, radially migrating neurons stop migration and form layers beneath the marginal zone (MZ). Reelin plays essential roles in these processes via its receptors, apolipoprotein E receptor 2 (ApoER2) and very low density lipoprotein receptor (VLDLR). Although we recently reported that reelin causes neuronal aggregation via ApoER2, which is thought to be important for the subsequent layer formation, it remains unknown what effect reelin exerts via the VLDLR. Here, we found that ectopic reelin overexpression in the Vldlr-mutant mouse cortex causes neuronal aggregation, but without an MZ-like cell-sparse central region that is formed when reelin is overexpressed in the normal cortex. We also found that both the early-born and late-born Vldlr-deficient neurons invade the MZ and exhibit impaired dendrite outgrowth from before birth. Rescue experiments indicate that VLDLR suppresses neuronal invasion into the MZ via a cell-autonomous mechanism, possibly mediated by Rap1, integrin and Akt. These results suggest that VLDLR is not a prerequisite for reelin-induced neuronal aggregation and that the major role of VLDLR is to suppress neuronal invasion into the MZ during neocortical development.
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Affiliation(s)
- Yuki Hirota
- Department of Anatomy, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Kazunori Nakajima
- Department of Anatomy, Keio University School of Medicine, Tokyo 160-8582, Japan
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14
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Cawley NX, Lyons AT, Abebe D, Wassif CA, Porter FD. Evaluation of the Potential Role of Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) in Niemann-Pick Disease, Type C1. Int J Mol Sci 2020; 21:E2430. [PMID: 32244519 DOI: 10.3390/ijms21072430] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/27/2020] [Accepted: 03/28/2020] [Indexed: 12/12/2022] Open
Abstract
Niemann–Pick disease, type C1, is a cholesterol storage disease where unesterified cholesterol accumulates intracellularly. In the cerebellum this causes neurodegeneration of the Purkinje neurons that die in an anterior-to-posterior and time-dependent manner. This results in cerebellar ataxia as one of the major outcomes of the disease. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a significant role in the regulation of serum cholesterol levels by modulating LDL receptor levels on peripheral tissues. In the central nervous system, PCSK9 may have a similar effect on the closely related VLDL and ApoE2 receptors to regulate brain cholesterol. In addition, regulation of VLDLR and ApoER2 by PCSK9 may contribute to neuronal apoptotic pathways through Reelin, the primary ligand of VLDLR and ApoER2. Defects in reelin signaling results in cerebellar dysfunction leading to ataxia as seen in the Reeler mouse. Our recent findings that Pcsk9 is expressed ~8-fold higher in the anterior lobules of the cerebellum compared to the posterior lobule X, which is resistant to neurodegeneration, prompted us to ask whether PCSK9 could play a role in NPC1 disease progression. We addressed this question genetically, by characterizing NPC1 disease in the presence or absence of PCSK9. Analysis of double mutant Pcsk9-/-/Npc1-/- mice by disease severity scoring, motor assessments, lifespan, and cerebellar Purkinje cell staining, showed no obvious difference in NPC1 disease progression with that of Npc1-/- mice. This suggests that PCSK9 does not play an apparent role in NPC1 disease progression.
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15
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Kizhakkedath P, John A, Al‐Sawafi BK, Al‐Gazali L, Ali BR. Endoplasmic reticulum quality control of LDLR variants associated with familial hypercholesterolemia. FEBS Open Bio 2019; 9:1994-2005. [PMID: 31587492 PMCID: PMC6823279 DOI: 10.1002/2211-5463.12740] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 09/05/2019] [Accepted: 10/04/2019] [Indexed: 02/05/2023] Open
Abstract
Loss-of-function mutations in the low-density lipoprotein receptor (LDLR) gene can cause familial hypercholesterolemia (FH), but detailed functional evidence for pathogenicity is limited to a few reported mutations. Here, we investigated the cellular pathogenic mechanisms of three mutations in LDLR causing FH, which are structurally identical to pathogenic mutations in the very low-density lipoprotein receptor (VLDLR). Similar to the VLDLR mutants, LDLR mutants D482H and C667F were found to be localized to the ER, while D445E, which is a conserved amino acid change, did not affect the trafficking of the receptor to the plasma membrane, as confirmed by the N-glycosylation profile. Although the ER-retained mutant proteins were soluble, induction of ER stress was observed as indicated by spliced X-box binding protein-1 (XBP-1) mRNA levels. The mutants were found to associate with ER quality control components, and their stability was enhanced by inhibitors of proteasome. Our results contribute to the growing list of transport-deficient class II LDLR variants leading to FH and provide evidence for the involvement of endoplasmic reticulum-associated degradation in their stability.
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Affiliation(s)
- Praseetha Kizhakkedath
- Department of PathologyCollege of Medicine and Health SciencesUnited Arab Emirates UniversityAl‐AinUnited Arab Emirates
| | - Anne John
- Department of PathologyCollege of Medicine and Health SciencesUnited Arab Emirates UniversityAl‐AinUnited Arab Emirates
| | - Buthaina K. Al‐Sawafi
- Department of PathologyCollege of Medicine and Health SciencesUnited Arab Emirates UniversityAl‐AinUnited Arab Emirates
| | - Lihadh Al‐Gazali
- Department of PaediatricsCollege of Medicine and Health SciencesUnited Arab Emirates UniversityAl‐AinUnited Arab Emirates
| | - Bassam R. Ali
- Department of PathologyCollege of Medicine and Health SciencesUnited Arab Emirates UniversityAl‐AinUnited Arab Emirates
- Zayed Center for Health SciencesUnited Arab Emirates UniversityAl‐AinUnited Arab Emirates
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16
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Abstract
Emerging evidence suggest that macrophage and osteoclast are two competing differentiation outcomes from myeloid progenitors. In this review, we summarize recent advances in the understanding of the molecular mechanisms controlling the polarization of macrophage and osteoclast. These include nuclear receptors/transcription factors such as peroxisome proliferator-activated receptor γ (PPARγ) and estrogen-related receptor α (ERRα), their transcription cofactor PPARγ coactivator 1-β (PGC-1β), metabolic factors such as mitochondrial complex I (CI) component NADH:ubiquinone oxidoreductase iron-sulfur protein 4 (Ndufs4), as well as transmembrane receptors such as very-low-density-lipoprotein receptor (VLDLR). These molecular rheostats promote osteoclast differentiation but suppress proinflammatory macrophage activation and inflammation, by acting lineage-intrinsically, systemically or cross generation. These findings provide new insights to the understanding of the interactions between innate immunity and bone remodeling, advancing the field of osteoimmunology.
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Affiliation(s)
- Dengbao Yang
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Yihong Wan
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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17
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Cao D, Wang W, Li S, Lai W, Huang X, Zhou J, Chen X, Li X. TLR2-Deficiency Promotes Prenatal LPS Exposure-Induced Offspring Hyperlipidemia. Front Physiol 2019; 10:1102. [PMID: 31507457 PMCID: PMC6713936 DOI: 10.3389/fphys.2019.01102] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/08/2019] [Indexed: 12/15/2022] Open
Abstract
Toll-like receptor 2 (TLR2), which recognizes several lipopeptides and transduces inflammatory signaling, promotes the pathogenesis of diet-induced dyslipidemia and obesity. TLR2-deficient mice were shown to have improved insulin sensitivity and reduced diet-induced metabolic syndrome. Previous studies demonstrated that prenatal lipopolysaccharide (LPS) exposure causes dyslipidemia accompanied by increased body weight and insulin resistance in offspring. To determine whether TLRs are involved in this complex abnormal phenotype, we analyzed TLR2 and TLR4 expression levels in adipose tissues from offspring with prenatal LPS-exposure (offspring-pLPS) and compared these levels to those of control offspring with prenatal saline-exposure (offspring-pSaline). TLR2 expression was specifically upregulated in the adipose tissue of offspring-pLPS mice. However, unexpectedly, TLR2-deficient offspring-pLPS mice not only presented with an abnormal phenotype comparable to that of wild-type offspring-pLPS mice but also exhibited significantly more severe hyperlipidemia. Our further analyses revealed a dramatic upregulation of TLR4 expression and overactivation of the TLR4/Myd88 signaling pathway in TLR2-deficient offspring-pLPS adipose tissue. Our finding suggests a compensatory genetic interaction between TLR2 and TLR4 in the context of prenatal inflammatory stimulation, and this interaction likely contributes to the prenatal inflammation-induced hyperlipidemia and lipid overload-induced obesity, thus providing a potential mechanism for the fetal origin of adult metabolic diseases.
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Affiliation(s)
- Dayan Cao
- Institute of Materia Medica, Department of Pharmaceutics, College of Pharmacy, Army Medical University, Chongqing, China
| | - Wenjia Wang
- Institute of Materia Medica, Department of Pharmaceutics, College of Pharmacy, Army Medical University, Chongqing, China
| | - Shuhui Li
- Department of Clinical Biochemistry, College of Pharmacy, Army Medical University, Chongqing, China
| | - Wenjing Lai
- Department of Pharmacy, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Xiaoyong Huang
- Institute of Immunology, PLA, Army Medical University, Chongqing, China
| | - Jianzhi Zhou
- Institute of Materia Medica, Department of Pharmaceutics, College of Pharmacy, Army Medical University, Chongqing, China
| | - Xin Chen
- Institute of Materia Medica, Department of Pharmaceutics, College of Pharmacy, Army Medical University, Chongqing, China
| | - Xiaohui Li
- Institute of Materia Medica, Department of Pharmaceutics, College of Pharmacy, Army Medical University, Chongqing, China
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18
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Kolaka R, Chotwiwatthanakun C, Chutabhakdikul N. Fetal exposure to high levels of maternal glucocorticoids alters reelin signaling in the prefrontal cortex of rat pups. Int J Dev Neurosci 2019; 78:185-190. [PMID: 31014819 DOI: 10.1016/j.ijdevneu.2019.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 04/06/2019] [Accepted: 04/10/2019] [Indexed: 10/27/2022] Open
Abstract
Maternal stress (MS) is associated with various neuropsychiatric disorders and cognitive impairment in the offspring. However, it is unclear how early life stress alters the pup's brain development and how it contributes to the pathology of neuropsychiatric disorders later in life. Reelin is a large extracellular matrix glycoprotein that plays essential roles in early brain development such as neural migration, synaptic development, and maturation. Dysregulation of reelin and its signaling proteins is associated with the emergence of neuropsychiatric disorders in adulthood. This study examined the effect of repeated maternal Carbenoxolone (CBX) injection during late gestation on reelin signaling in the prefrontal cortex (PFC) of rat pups. CBX is a selective 11β-HSD2 enzyme inhibitor that promotes the direct transfer of maternal corticosteroids (CORT) to the fetus. Therefore, treatment with CBX can mimic the animal model of early life exposure to high levels of maternal stress hormone. In this study, pregnant rats were injected daily with either saline or CBX during gestation day (GD) 14-21, and the levels of reelin and its signaling proteins were examined in the PFC of rat pups at different postnatal age from P0-P21. The main result of this study is the repeated maternal CBX injections during GD14-21 acutely increase reln mRNA and protein expression in the PFC of rat pups at birth (P0) and follow by a significant decrease during P7-P14. The treatment also causes long term decreases in the amount of VLDLR and Dab1 which are the downstream signaling proteins for the reelin pathway, at least until P21. Our results indicated that fetal exposure to high levels of maternal CORT interferes with reelin signaling which might have profound effects on cortical development associated with neuropsychiatric disorders later in life.
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Affiliation(s)
- Ratirat Kolaka
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Nakornpathom, Thailand
| | | | - Nuanchan Chutabhakdikul
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Nakornpathom, Thailand
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19
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Zarei M, Barroso E, Palomer X, Escolà-Gil JC, Cedó L, Wahli W, Vázquez-Carrera M. Pharmacological PPARβ/δ activation upregulates VLDLR in hepatocytes. Clin Investig Arterioscler 2019; 31:111-118. [PMID: 30987865 DOI: 10.1016/j.arteri.2019.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 01/08/2019] [Accepted: 01/17/2019] [Indexed: 12/12/2022]
Abstract
The very low-density lipoprotein receptor (VLDLR) plays an important function in the control of serum triglycerides and in the development of non-alcoholic fatty liver disease (NAFLD). In this study, we investigated the role of peroxisome proliferator-activated receptor (PPAR)β/δ activation in hepatic VLDLR regulation. Treatment of mice fed a high-fat diet with the PPARβ/δ agonist GW501516 increased the hepatic expression of Vldlr. Similarly, exposure of human Huh-7 hepatocytes to GW501516 increased the expression of VLDLR and triglyceride accumulation, the latter being prevented by VLDLR knockdown. Finally, treatment with another PPARβ/δ agonist increased VLDLR levels in the liver of wild-type mice, but not PPARβ/δ-deficient mice, confirming the regulation of hepatic VLDLR by this nuclear receptor. Our results suggest that upregulation of hepatic VLDLR by PPARβ/δ agonists might contribute to the hypolipidemic effect of these drugs by increasing lipoprotein delivery to the liver. Overall, these findings provide new effects by which PPARβ/δ regulate VLDLR levels and may influence serum triglyceride levels and NAFLD development.
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Affiliation(s)
- Mohammad Zarei
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM), Instituto de Salud Carlos III, Spain; Research Institute, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Emma Barroso
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM), Instituto de Salud Carlos III, Spain; Research Institute, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Xavier Palomer
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM), Instituto de Salud Carlos III, Spain; Research Institute, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Joan Carles Escolà-Gil
- Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM), Instituto de Salud Carlos III, Spain; Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Barcelona, Spain; Departament de Bioquímica i Biología Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Lidia Cedó
- Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM), Instituto de Salud Carlos III, Spain; Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Barcelona, Spain; Departament de Bioquímica i Biología Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Walter Wahli
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore; INRA ToxAlim, UMR1331, Chemin de Tournefeuille, Toulouse Cedex, France
| | - Manuel Vázquez-Carrera
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM), Instituto de Salud Carlos III, Spain; Research Institute, Hospital Sant Joan de Déu, Barcelona, Spain.
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Dlugosz P, Tresky R, Nimpf J. Differential Action of Reelin on Oligomerization of ApoER2 and VLDL Receptor in HEK293 Cells Assessed by Time-Resolved Anisotropy and Fluorescence Lifetime Imaging Microscopy. Front Mol Neurosci 2019; 12:53. [PMID: 30873003 PMCID: PMC6403468 DOI: 10.3389/fnmol.2019.00053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/12/2019] [Indexed: 01/12/2023] Open
Abstract
The canonical Reelin signaling cascade regulates correct neuronal layering during embryonic brain development. Details of this pathway are still not fully understood since the participating components are highly variable and create a complex mixture of interacting molecules. Reelin is proteolytically processed resulting in five different fragments some of which carrying the binding site for two different but highly homologous receptors, apolipoprotein E receptor 2 (ApoER2) and very low density lipoprotein receptor (VLDLR). The receptors are expressed in different variants in different areas of the developing brain. Binding of Reelin and its central fragment to the receptors results in phosphorylation of the intracellular adapter disabled-1 (Dab1) in neurons. Here, we studied the changes of the arrangement of the receptors upon Reelin binding and its central fragment at the molecular level in human embryonic kidney 293 (HEK293) cells by time-resolved anisotropy and fluorescence lifetime imaging microscopy (FLIM). In the off-state of the pathway ApoER2 and VLDLR form homo or hetero-di/oligomers. Upon binding of full length Reelin ApoER2 and VLDLR homo-oligomers are rearranged to higher order receptor clusters which leads to Dab1 phosphorylation. When the central fragment of Reelin binds to the receptors the cluster size of homo-oligomers is not affected and Dab1 is not phosphorylated. Hetero-oligomerization, however, can be induced, but does not lead to Dab1 phosphorylation. Cells expressing only ApoER2 or VLDLR change their shape when stimulated with the central fragment. Cells expressing ApoER2 produce filopodia/lamellipodia and cell size increases, whereas VLDLR-expressing cells decrease in size. These findings demonstrate that the primary event in the canonical Reelin pathway is the rearrangement of preformed receptor homo-oligomers to higher order clusters. In addition the possibility of yet another signaling mechanism which is mediated by the central Reelin fragment independent of Dab1 phosphorylation became apparent.
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Affiliation(s)
- Paula Dlugosz
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University Vienna, Vienna, Austria
| | - Roland Tresky
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University Vienna, Vienna, Austria
| | - Johannes Nimpf
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University Vienna, Vienna, Austria
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Huynh H, Wei W, Wan Y. mTOR Inhibition Subdues Milk Disorder Caused by Maternal VLDLR Loss. Cell Rep 2018; 19:2014-2025. [PMID: 28591574 DOI: 10.1016/j.celrep.2017.05.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 04/14/2017] [Accepted: 05/10/2017] [Indexed: 01/01/2023] Open
Abstract
It is unknown whether and how very-low density lipoprotein receptors (VLDLRs) impact skeletal homeostasis. Here, we report that maternal and offspring VLDLRs play opposite roles in osteoclastogenesis and bone resorption. VLDLR deletion in the offspring augments osteoclast differentiation by enhancing RANKL signaling, leading to osteoporosis. In contrast, VLDLR deletion in the mother alters milk metabolism, which inhibits osteoclast differentiation and causes osteopetrosis in the offspring. The maternal effects are dominant. VLDLR-null lactating mammary gland exhibits higher mTORC1 signaling and cholesterol biosynthesis. Pharmacological probing reveals that rapamycin, but not statin, treatment of the VLDLR-null mother can prevent both the low bone resorption and our previously described inflammatory fur loss in their offspring. Genetic rescue reveals that maternal mTORC1 attenuation in adipocytes, but not in myeloid cells, prevents offspring osteopetrosis and fur loss. Our studies uncover functions of VLDLR and mTORC1 in lactation and osteoclastogenesis, illuminating key mechanisms and therapeutic insights for bone and metabolic diseases.
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Affiliation(s)
- HoangDinh Huynh
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Wei Wei
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yihong Wan
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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22
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Lauda A, Bruehschwein A, Ficek J, Schmidt MJ, Klima A, Meyer-Lindenberg A, Fischer A. Caudal Fossa Ratio in Normal Dogs and Eurasier Dogs with VLDLR-Associated Genetic Cerebellar Hypoplasia. Front Vet Sci 2018; 4:241. [PMID: 29404343 PMCID: PMC5786823 DOI: 10.3389/fvets.2017.00241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 12/20/2017] [Indexed: 12/26/2022] Open
Abstract
Cerebellar and hindbrain malformations, such as cerebellar hypoplasia (CH), vermis hypoplasia, and Dandy–Walker malformation, occur in dogs as well as in humans. Neuroimaging is essential for a precise description of these malformations and defining translational animal models. Neuroimaging is increasingly performed in puppies, but there is a lack of data on developmental changes in the caudal fossa, which can impair assessment of caudal fossa size in this age group. The purpose of this study was to validate caudal fossa ratio (CFR) in dogs and to explore CFR in Eurasier dogs with genetic CH. CFR was calculated from midsagittal brain images of 130 dogs as caudal fossa area/total cranial cavity area. In addition, the volume of the caudal fossa was measured in 64 randomly selected dogs from this group. Repeated measurements were used to investigate inter- and intra-rater variability and influence of imaging modality. Furthermore, the influence of age, weight, and breed was explored. The CFR was a reliable parameter with negligible influence from the examiners, imaging modality, and weight of the dog. The midsagittal area of the caudal fossa and the volume of the caudal fossa correlated closely with each other. In this study, we observed a smaller CFR in puppies. The CFR in adult dogs lies within 0.255 and 0.330, while CFR is smaller in puppies up to 4 months of age. Besides age, there was also an effect of breed, which should be explored in larger data sets. Measurements of CFR in Eurasier dogs with genetic CH caused by a mutation in the very-low-density-lipoprotein-receptor gene revealed the presence of two variants, one with an enlarged caudal fossa and one with a normal to small caudal fossa. This observation indicates that there is phenotypic heterogeneity and interaction between the developing cerebellum and the surrounding mesenchyme in this animal model.
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Affiliation(s)
- Alexander Lauda
- Centre for Clinical Veterinary Medicine, Clinic of Small Animal Medicine, LMU Munich, Munich, Germany
| | - Andreas Bruehschwein
- Centre for Clinical Veterinary Medicine, Clinic of Small Animal Surgery and Reproduction, LMU Munich, Munich, Germany
| | - Joanna Ficek
- Statistical Consulting Unit StaBLab, Department of Statistics, LMU Munich, Munich, Germany
| | - Martin J Schmidt
- Department of Veterinary Clinical Science, Small Animal Clinic, Justus-Liebig-University, Giessen, Germany
| | - André Klima
- Statistical Consulting Unit StaBLab, Department of Statistics, LMU Munich, Munich, Germany
| | - Andrea Meyer-Lindenberg
- Centre for Clinical Veterinary Medicine, Clinic of Small Animal Surgery and Reproduction, LMU Munich, Munich, Germany
| | - Andrea Fischer
- Centre for Clinical Veterinary Medicine, Clinic of Small Animal Medicine, LMU Munich, Munich, Germany
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Zarei M, Barroso E, Palomer X, Dai J, Rada P, Quesada-López T, Escolà-Gil JC, Cedó L, Zali MR, Molaei M, Dabiri R, Vázquez S, Pujol E, Valverde ÁM, Villarroya F, Liu Y, Wahli W, Vázquez-Carrera M. Hepatic regulation of VLDL receptor by PPARβ/δ and FGF21 modulates non-alcoholic fatty liver disease. Mol Metab 2017; 8:117-131. [PMID: 29289645 PMCID: PMC5985050 DOI: 10.1016/j.molmet.2017.12.008] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 12/08/2017] [Accepted: 12/13/2017] [Indexed: 12/22/2022] Open
Abstract
Objective The very low-density lipoprotein receptor (VLDLR) plays an important role in the development of hepatic steatosis. In this study, we investigated the role of Peroxisome Proliferator-Activated Receptor (PPAR)β/δ and fibroblast growth factor 21 (FGF21) in hepatic VLDLR regulation. Methods Studies were conducted in wild-type and Pparβ/δ-null mice, primary mouse hepatocytes, human Huh-7 hepatocytes, and liver biopsies from control subjects and patients with moderate and severe hepatic steatosis. Results Increased VLDLR levels were observed in liver of Pparβ/δ-null mice and in Pparβ/δ-knocked down mouse primary hepatocytes through mechanisms involving the heme-regulated eukaryotic translation initiation factor 2α (eIF2α) kinase (HRI), activating transcription factor (ATF) 4 and the oxidative stress-induced nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathways. Moreover, by using a neutralizing antibody against FGF21, Fgf21-null mice and by treating mice with recombinant FGF21, we show that FGF21 may protect against hepatic steatosis by attenuating endoplasmic reticulum (ER) stress-induced VLDLR upregulation. Finally, in liver biopsies from patients with moderate and severe hepatic steatosis, we observed an increase in VLDLR levels that was accompanied by a reduction in PPARβ/δ mRNA abundance and DNA-binding activity compared with control subjects. Conclusions Overall, these findings provide new mechanisms by which PPARβ/δ and FGF21 regulate VLDLR levels and influence hepatic steatosis development. PPARβ/δ deficiency leads to increased levels of hepatic VLDLR levels. FGF21 protects against hepatic steatosis by attenuating ER stress-induced VLDLR upregulation. Human hepatic steatosis is accompanied by increased levels of VLDLR and reduced expression of PPARβ/δ. PPARβ/δ and FGF21 may influence NAFLD development by regulating VLDLR levels.
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Affiliation(s)
- Mohammad Zarei
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain; Research Institute-Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Emma Barroso
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain; Research Institute-Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Xavier Palomer
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain; Research Institute-Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain
| | - Jianli Dai
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Shanghai, China
| | - Patricia Rada
- Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain; Instituto de Investigaciones Biomédicas Alberto Sols (CSIC/UAM), Madrid, Spain
| | - Tania Quesada-López
- Research Institute-Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine and IBUB, University of Barcelona, Barcelona, Spain; Spanish Biomedical Research Center in Physiopathology of Obesity and Nutrition (CIBEROBN)-Instituto de Salud Carlos III, Spain
| | - Joan Carles Escolà-Gil
- Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain; Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Barcelona, Spain; Departament de Bioquímica i Biología Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Lidia Cedó
- Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain; Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Barcelona, Spain
| | - Mohammad Reza Zali
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahsa Molaei
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Reza Dabiri
- lnternal Medicine Department, Semnan University of Medical Sciences, Semnan, Iran
| | - Santiago Vázquez
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
| | - Eugènia Pujol
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
| | - Ángela M Valverde
- Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain; Instituto de Investigaciones Biomédicas Alberto Sols (CSIC/UAM), Madrid, Spain
| | - Francesc Villarroya
- Research Institute-Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine and IBUB, University of Barcelona, Barcelona, Spain; Spanish Biomedical Research Center in Physiopathology of Obesity and Nutrition (CIBEROBN)-Instituto de Salud Carlos III, Spain
| | - Yong Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Institute for Advanced Studies, Wuhan University, Wuhan, China
| | - Walter Wahli
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland; Lee Kong Chian School of Medicine, Nanyang Technological University, 308232, Singapore; INRA ToxAlim, UMR1331, Chemin de Tournefeuille, Toulouse Cedex, France
| | - Manuel Vázquez-Carrera
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Center in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Barcelona, Spain; Research Institute-Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain.
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Santana J, Marzolo MP. The functions of Reelin in membrane trafficking and cytoskeletal dynamics: implications for neuronal migration, polarization and differentiation. Biochem J 2017; 474:3137-65. [PMID: 28887403 DOI: 10.1042/BCJ20160628] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Ha S, Tripathi PP, Mihalas AB, Hevner RF, Beier DR. C-Terminal Region Truncation of RELN Disrupts an Interaction with VLDLR, Causing Abnormal Development of the Cerebral Cortex and Hippocampus. J Neurosci 2017; 37:960-71. [PMID: 28123028 DOI: 10.1523/JNEUROSCI.1826-16.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 11/03/2016] [Accepted: 11/19/2016] [Indexed: 11/21/2022] Open
Abstract
We discovered a hypomorphic reelin (Reln) mutant with abnormal cortical lamination and no cerebellar hypoplasia. This mutant, RelnCTRdel, carries a chemically induced splice-site mutation that truncates the C-terminal region (CTR) domain of RELN protein and displays remarkably distinct phenotypes from reeler The mutant does not have an inverted cortex, but cortical neurons overmigrate and invade the marginal zone, which are characteristics similar to a phenotype seen in the cerebral cortex of Vldlrnull mice. The dentate gyrus shows a novel phenotype: the infrapyramidal blade is absent, while the suprapyramidal blade is present and laminated. Genetic epistasis analysis showed that RelnCTRdel/Apoer2null double homozygotes have phenotypes akin to those of reeler mutants, while RelnCTRdel/Vldlrnull mice do not. Given that the receptor double knock-out mice resemble reeler mutants, we infer that RelnCTRdel/Apoer2null double homozygotes have both receptor pathways disrupted. This suggests that CTR-truncation disrupts an interaction with VLDLR (very low-density lipoprotein receptor), while the APOER2 signaling pathway remains active, which accounts for the hypomorphic phenotype in RelnCTRdel mice. A RELN-binding assay confirms that CTR truncation significantly decreases RELN binding to VLDLR, but not to APOER2. Together, the in vitro and in vivo results demonstrate that the CTR domain confers receptor-binding specificity of RELN. SIGNIFICANCE STATEMENT Reelin signaling is important for brain development and is associated with human type II lissencephaly. Reln mutations in mice and humans are usually associated with cerebellar hypoplasia. A new Reln mutant with a truncation of the C-terminal region (CTR) domain shows that Reln mutation can cause abnormal phenotypes in the cortex and hippocampus without cerebellar hypoplasia. Genetic analysis suggested that CTR truncation disrupts an interaction with the RELN receptor VLDLR (very low-density lipoprotein receptor); this was confirmed by a RELN-binding assay. This result provides a mechanistic explanation for the hypomorphic phenotype of the CTR-deletion mutant, and further suggests that Reln mutations may cause more subtle forms of human brain malformation than classic lissencephalies.
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Sun Y, Liegl R, Gong Y, Bühler A, Cakir B, Meng SS, Burnim SB, Liu CH, Reuer T, Zhang P, Walz JM, Ludwig F, Lange C, Agostini H, Böhringer D, Schlunck G, Smith LEH, Stahl A. Sema3f Protects Against Subretinal Neovascularization In Vivo. EBioMedicine 2017; 18:281-287. [PMID: 28373097 PMCID: PMC5405173 DOI: 10.1016/j.ebiom.2017.03.026] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 03/17/2017] [Accepted: 03/17/2017] [Indexed: 12/26/2022] Open
Abstract
Pathological neovascularization of the outer retina is the hallmark of neovascular age-related macular degeneration (nAMD). Building on our previous observations that semaphorin 3F (Sema3f) is expressed in the outer retina and demonstrates anti-angiogenic potential, we have investigated whether Sema3f can be used to protect against subretinal neovascularization in two mouse models. Both in the very low-density lipid-receptor knockout (Vldlr−/−) model of spontaneous subretinal neovascularization as well as in the mouse model of laser-induced choroidal neovascularization (CNV), we found protective effects of Sema3f against the formation of pathologic neovascularization. In the Vldlr−/− model, AAV-induced overexpression of Sema3f reduced the size of pathologic neovascularization by 56%. In the laser-induced CNV model, intravitreally injected Sema3f reduced pathologic neovascularization by 30%. Combined, these results provide the first evidence from two distinct in vivo models for a use of Sema3f in protecting the outer retina against subretinal neovascularization. Sema3f is expressed in the physiologically avascular layers of the outer retina. Vldlr−/− mice have reduced Sema3f and form spontaneous subretinal neovascularization. AAV-mediated increase of Sema3f protects against neovascularization in Vldlr−/− mice. Sema3f also reduces pathologic neovascularization in eyes with laser-induced CNV.
Abnormal formation of new blood vessels in the retina is one of the hallmarks of a potentially blinding eye disease called wet (or exudative) macular degeneration. Here we investigated in two independent mouse models whether Sema3f (a protein involved in guiding blood vessel growth) can be modulated to protect against abnormal blood vessel growth. In both mouse models, we found protective effects of Sema3f against abnormal blood vessel formation in the retina. Combined, these results provide the first evidence that Sema3f could be modulated to protect against wet macular degeneration.
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Affiliation(s)
- Ye Sun
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Raffael Liegl
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Yan Gong
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Anima Bühler
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Bertan Cakir
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Steven S Meng
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Samuel B Burnim
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Chi-Hsiu Liu
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Tristan Reuer
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Peipei Zhang
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Johanna M Walz
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Franziska Ludwig
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Clemens Lange
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Hansjürgen Agostini
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Daniel Böhringer
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Günther Schlunck
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany
| | - Lois E H Smith
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Andreas Stahl
- Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany.
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Riaz MA, Stammler A, Borgers M, Konrad L. Clusterin signals via ApoER2/ VLDLR and induces meiosis of male germ cells. Am J Transl Res 2017; 9:1266-1276. [PMID: 28386352 PMCID: PMC5376017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 10/24/2016] [Indexed: 06/07/2023]
Abstract
Clusterin (CLU) is a ubiquitously expressed heterodimeric glycoprotein that is involved in a variety of functions like cell-cell interactions, apoptosis, epithelial-mesenchymal transition, carcinogenesis, and chaperone function. In the testis, CLU is strongly expressed especially in Sertoli cells but very little is known about its testicular function, regulation of secretion and most enigmatic, its receptor(s). In this study, we approached these questions with a special emphasis on the link between CLU and meiosis. In cultured seminiferous tubules, we found that secretion of CLU protein is upregulated by transforming growth factor-betas (TGF-β1-3) and observed inhibition of staurosporine-induced apoptosis by recombinant CLU. Clusterin signaling in testicular cells seems to be modulated by very low density lipoprotein receptor (VLDLR) and apolipoprotein E receptor 2 (ApoER2), because these members of the low density lipoprotein (LDL) receptor family are present in rat germ cells. Furthermore, inhibition of VLDLR/ApoER2 by a specific inhibitor abrogates CLU-mediated phosphorylation of Akt, which mediates VLDLR/ApoER2 signaling. We could also show in tubules treated with recombinant CLU a significant upregulation of several meiosis-associated proteins such as V-myb avian myeloblastosis viral oncogene homolog-like 1 (Mybl1), stimulated by retinoic acid gene 8 (Stra8), lactate dehydrogenase C (LDHC), cAMP response element-binding protein (CREB) and histone H3 (H3S10P). Collectively, our data show for the first time the involvement of CLU in upregulation of meiosis through VLDLR/ApoER2 in male germ cells.
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Affiliation(s)
- Muhammad Assad Riaz
- Center of Gynecology and Obstetrics, Medical Faculty, Feulgenstr. 12, Justus-Liebig-University Giessen35392, Giessen, Germany
| | - Angelika Stammler
- Institute of Anatomy and Cell Biology, Signaling Group, Justus-Liebig-University Giessen35392, Giessen, Germany
| | - Mareike Borgers
- Center of Gynecology and Obstetrics, Medical Faculty, Feulgenstr. 12, Justus-Liebig-University Giessen35392, Giessen, Germany
| | - Lutz Konrad
- Center of Gynecology and Obstetrics, Medical Faculty, Feulgenstr. 12, Justus-Liebig-University Giessen35392, Giessen, Germany
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Mihail A, Coman G, Staniceanu F, Coman L, Zurac S, Coman OA. Reelin and its receptors, VLDLR and ApoER2, in melanocytic nevi. J Med Life 2017; 10:85-89. [PMID: 28255385 PMCID: PMC5304381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Reelin is an extracellular signaling protein synthesized by Cajal-Retius cells in utero and early after birth, its presence being signaled in adult life too. Reelin acts on its receptors, VLDLR and ApoER2, acting on cytoskeleton, controlling migration and subsequently positioning and stabilizing the cortical neurons. We investigated the reelin presence and its receptors, VLDLR and ApoER2, in melanocytic nevi considering the neural crest origin of the nevus cells and their migration into skin during embrionary period. Melanocytic nevi present a strict cellular architecture and an increased malignant transforming capacity. We investigated reelin presence in 32 melanocytic nevi (5 junctional, 27 compound or 14 dysplastic nevi and 18 non dysplastic nevi). The assessment of reelin presence was performed by histological semiquantitative criteria. Results showed the presence of reelin in 29 cases (29/ 32). The presence of reelin was elevated in junctional areas as in dysplastic nevi. VLDLR presented positive values in 16 cases (16/ 32) and ApoER2 was weak positive in 7 cases. Reelin or its receptors was peritumorally absent. Our study showed the presence of reelin in nevus cells from cutaneous melanocytic nevi and, in these cells, only the VLDLR receptor was present in half of the cases. The significance of the reelin presence in cutaneous nevus cells may be hypothetically considered correlated with the position maintenance of the nevus cells or migration of these cells in malignant transforming situation. Abbreviations: ApoER2 = apolipoprotein receptor 2, VLDLR = very low density lipoprotein receptor, DAB-1 = DIABLO protein, HMB45 = gene HMB45.
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Affiliation(s)
- A Mihail
- Department of Dermatology, “Dr. Victor Babeş” Clinical Hospital of Infectious and Tropical Diseases, Bucharest, Romania
,Department of Dermatology, “Titu Maiorescu” University, Bucharest, Romania
| | - G Coman
- Department of Dermatology, “Dr. Victor Babeş” Clinical Hospital of Infectious and Tropical Diseases, Bucharest, Romania
| | - F Staniceanu
- Department of Pathology, “Colentina” Clinical Hospital Bucharest, Romania
| | - L Coman
- Department of Physiology, Faculty of Medicine, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania
| | - S Zurac
- Department of Pathology, “Colentina” Clinical Hospital Bucharest, Romania
| | - OA Coman
- Department of Dermatology, “Dr. Victor Babeş” Clinical Hospital of Infectious and Tropical Diseases, Bucharest, Romania
,Department of Pharmacology, Faculty of Medicine, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania
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Micalizzi A, Moroni I, Ginevrino M, Biagini T, Mazza T, Romani M, Valente EM. Very mild features of dysequilibrium syndrome associated with a novel VLDLR missense mutation. Neurogenetics 2016; 17:191-5. [PMID: 27251579 DOI: 10.1007/s10048-016-0488-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/29/2016] [Indexed: 10/21/2022]
Abstract
Dysequilibrium syndrome (DES) is a non-progressive congenital ataxia characterized by severe intellectual deficit, truncal ataxia and markedly delayed, quadrupedal or absent ambulation. Recessive loss-of-function mutations in the very low density lipoprotein receptor (VLDLR) gene represent the most common cause of DES. Only two families have been reported harbouring homozygous missense mutations, both with a similarly severe phenotype. We report an Italian girl with very mild DES caused by the novel homozygous VLDLR missense mutation p.(C419Y). This unusually benign phenotype possibly relates to a less disruptive effect of the mutation, falling within a domain (EGF-B) not predicted as crucial for the protein function.
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Ranaivoson FM, von Daake S, Comoletti D. Structural Insights into Reelin Function: Present and Future. Front Cell Neurosci 2016; 10:137. [PMID: 27303268 PMCID: PMC4882317 DOI: 10.3389/fncel.2016.00137] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 05/10/2016] [Indexed: 12/20/2022] Open
Abstract
Reelin is a neuronal glycoprotein secreted by the Cajal-Retzius cells in marginal regions of the cerebral cortex and the hippocampus where it plays important roles in the control of neuronal migration and the formation of cellular layers during brain development. This 3461 residue-long protein is composed of a signal peptide, an F-spondin-like domain, eight Reelin repeats (RR1-8), and a positively charged sequence at the C-terminus. Biochemical data indicate that the central region of Reelin binds to the low-density lipoprotein receptors apolipoprotein E receptor 2 (ApoER2) and the very-low-density lipoprotein receptor (VLDLR), leading to the phosphorylation of the intracellular adaptor protein Dab1. After secretion, Reelin is rapidly degraded in three major fragments, but the functional significance of this degradation is poorly understood. Probably due to its large mass and the complexity of its architecture, the high-resolution, three-dimensional structure of Reelin has never been determined. However, the crystal structures of some of the RRs have been solved, providing important insights into their fold and the interaction with the ApoER2 receptor. This review discusses the current findings on the structure of Reelin and its binding to the ApoER2 and VLDLR receptors, and we discuss some areas where proteomics and structural biology can help understanding Reelin function in brain development and human health.
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Affiliation(s)
- Fanomezana M Ranaivoson
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA; Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA
| | - Sventja von Daake
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA; Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA
| | - Davide Comoletti
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA; Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA; Department of Pediatrics, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA
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Valence S, Garel C, Barth M, Toutain A, Paris C, Amsallem D, Barthez MA, Mayer M, Rodriguez D, Burglen L. RELN and VLDLR mutations underlie two distinguishable clinico-radiological phenotypes. Clin Genet 2016; 90:545-549. [PMID: 27000652 DOI: 10.1111/cge.12779] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 12/17/2022]
Abstract
Pontocerebellar hypoplasias (PCH) are characterized by lack of development and/or early neurodegeneration of cerebellum and brainstem. We report five patients referred for PCH, showing atypical clinical and magnetic resonance imaging (MRI) features suggestive of defects in the Reelin pathway. We screened for mutations in RELN or VLDLR and compared the phenotype of these patients with that of previously reported patients. All patients had profound cerebellar hypoplasia on MRI with peculiar cerebellar morphology, associated with flattened pons and neocortical abnormalities. Patient 1 had profound motor and intellectual disability with moderate lissencephaly suggestive of RELN mutations and was shown to harbor a splicing homozygous RELN mutation. The four other patients had a milder phenotype consistent with CARMQ1 (cerebellar ataxia and mental retardation with or without quadrupedal locomotion). These patients showed mild simplification or thickening of cortical gyration and had VLDLR mutations. Reelin signaling regulates neuronal migration in the developing mammalian brain. VLDLR is a key component of the Reelin pathway. Our patients had a very small and dysplatic cerebellar vermis that should suggest the involvement of these genes. Moreover, differences in clinical severity, involvement of the cerebellar hemispheres, together with the severity of the neocortical defect, enables RELN-mutated patients to be distinguished from VLDLR-mutated patients.
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Affiliation(s)
- S Valence
- APHP, GHUEP, Hôpital Armand Trousseau, Centre de Référence 'Malformations et maladies congénitales du cervelet', Paris, France.,APHP, GHUEP, Hôpital Armand-Trousseau, Service de Neuropédiatrie, Paris, France.,Sorbonne Universités, UPMC Université Paris 06, GRC-UPMC ConCer-LD, Paris, France
| | - C Garel
- APHP, GHUEP, Hôpital Armand Trousseau, Centre de Référence 'Malformations et maladies congénitales du cervelet', Paris, France.,APHP, GHUEP, Hôpital Armand-Trousseau, Service de Radiologie, Paris, France
| | - M Barth
- Service de Génétique, CHU d'Angers, Angers, France
| | - A Toutain
- Service de Génétique, CHU de Tours, and UMR_INSERM U930, Faculté de Médecine, Université François Rabelais, Tours, France
| | - C Paris
- Service de Neurologie Pédiatrique, CHU J Minjoz, Besançon, France
| | - D Amsallem
- Service de Neurologie Pédiatrique, CHU J Minjoz, Besançon, France
| | - M-A Barthez
- Service de Neurologie Pédiatrique, CHU de Tours, Tours, France
| | - M Mayer
- APHP, GHUEP, Hôpital Armand-Trousseau, Service de Neuropédiatrie, Paris, France
| | - D Rodriguez
- APHP, GHUEP, Hôpital Armand Trousseau, Centre de Référence 'Malformations et maladies congénitales du cervelet', Paris, France.,APHP, GHUEP, Hôpital Armand-Trousseau, Service de Neuropédiatrie, Paris, France.,Sorbonne Universités, UPMC Université Paris 06, GRC-UPMC ConCer-LD, Paris, France
| | - L Burglen
- APHP, GHUEP, Hôpital Armand Trousseau, Centre de Référence 'Malformations et maladies congénitales du cervelet', Paris, France.,Neuroprotection du cerveau en développement, INSERM U1141, Paris, France.,APHP, GHUEP, Hôpital Armand-Trousseau, Département de Génétique, Paris, France
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Adam I, Mendoza E, Kobalz U, Wohlgemuth S, Scharff C. FoxP2 directly regulates the reelin receptor VLDLR developmentally and by singing. Mol Cell Neurosci 2016; 74:96-105. [PMID: 27105823 DOI: 10.1016/j.mcn.2016.04.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 03/10/2016] [Accepted: 04/18/2016] [Indexed: 12/15/2022] Open
Abstract
Mutations of the transcription factor FOXP2 cause a severe speech and language disorder. In songbirds, FoxP2 is expressed in the medium spiny neurons (MSNs) of the avian basal ganglia song nucleus, Area X, which is crucial for song learning and adult song performance. Experimental downregulation of FoxP2 in Area X affects spine formation, prevents neuronal plasticity induced by social context and impairs song learning. Direct target genes of FoxP2 relevant for song learning and song production are unknown. Here we show that a lentivirally mediated FoxP2 knockdown in Area X of zebra finches downregulates the expression of VLDLR, one of the two reelin receptors. Zebra finch FoxP2 binds to the promoter of VLDLR and activates it, establishing VLDLR as a direct FoxP2 target. Consistent with these findings, VLDLR expression is co-regulated with FoxP2 as a consequence of adult singing and during song learning. We also demonstrate that knockdown of FoxP2 affects glutamatergic transmission at the corticostriatal MSN synapse. These data raise the possibility that the regulatory relationship between FoxP2 and VLDLR guides structural plasticity towards the subset of FoxP2-positive MSNs in an activity dependent manner via the reelin pathway.
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Affiliation(s)
- Iris Adam
- Department for Animal Behavior, Freie Universität Berlin, Takustr. 6, 14195 Berlin, Germany.
| | - Ezequiel Mendoza
- Department for Animal Behavior, Freie Universität Berlin, Takustr. 6, 14195 Berlin, Germany.
| | - Ursula Kobalz
- Department for Animal Behavior, Freie Universität Berlin, Takustr. 6, 14195 Berlin, Germany.
| | - Sandra Wohlgemuth
- Department for Animal Behavior, Freie Universität Berlin, Takustr. 6, 14195 Berlin, Germany.
| | - Constance Scharff
- Department for Animal Behavior, Freie Universität Berlin, Takustr. 6, 14195 Berlin, Germany.
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Kysenius K, Huttunen HJ. Stress-induced upregulation of VLDL receptor alters Wnt-signaling in neurons. Exp Cell Res 2016; 340:238-47. [PMID: 26751967 DOI: 10.1016/j.yexcr.2016.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 12/16/2015] [Accepted: 01/01/2016] [Indexed: 12/12/2022]
Abstract
Lipoprotein receptor family members hold multiple roles in the brain, and alterations in lipoprotein receptor expression and function are implicated in neuronal stress, developmental disorders and neurodegenerative diseases, such as Alzheimer's disease. Berberine (BBR), a nutraceutical shown to have both neuroprotective and neurotoxic properties, is suggested to regulate lipoprotein receptor expression. We show that subtoxic concentration of BBR regulates neuronal lipoprotein receptor expression in a receptor- and time-dependent fashion in cerebellar granule neurons (CGN). Similarly to BBR, subtoxic concentrations of neuronal stressors cobalt chloride, thapsigargin and rotenone increased very-low-density lipoprotein receptor (VLDLR) mRNA and protein expression in CGN suggesting a conserved pathway for stress-induced upregulation of VLDLR in neurons. We also show that VLDLR upregulation is accompanied by transiently increased stabilization of hypoxia-induced factor 1 alpha (HIF-1α) and decreased β-catenin levels affecting the Wnt pathway through GSK3β phosphorylation, a crucial player in neurodegenerative processes. Our results indicate that neuronal stress differentially regulates lipoprotein receptor expression in neurons, with VLDLR upregulation as a common element as a modulator of neuronal Wnt signaling.
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Ujino S, Nishitsuji H, Hishiki T, Sugiyama K, Takaku H, Shimotohno K. Hepatitis C virus utilizes VLDLR as a novel entry pathway. Proc Natl Acad Sci U S A. 2016;113:188-193. [PMID: 26699506 DOI: 10.1073/pnas.1506524113] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Various host factors are involved in the cellular entry of hepatitis C virus (HCV). In addition to the factors previously reported, we discovered that the very-low-density lipoprotein receptor (VLDLR) mediates HCV entry independent of CD81. Culturing Huh7.5 cells under hypoxic conditions significantly increased HCV entry as a result of the expression of VLDLR, which was not expressed under normoxic conditions in this cell line. Ectopic VLDLR expression conferred susceptibility to HCV entry of CD81-deficient Huh7.5 cells. Additionally, VLDLR-mediated HCV entry was not affected by the knockdown of cellular factors known to act as HCV receptors or HCV entry factors. Because VLDLR is expressed in primary human hepatocytes, our results suggest that VLDLR functions in vivo as an HCV receptor independent of canonical CD81-mediated HCV entry.
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Wang Z, Cheng R, Lee K, Tyagi P, Ding L, Kompella UB, Chen J, Xu X, Ma JX. Nanoparticle-mediated expression of a Wnt pathway inhibitor ameliorates ocular neovascularization. Arterioscler Thromb Vasc Biol 2015; 35:855-64. [PMID: 25657312 DOI: 10.1161/atvbaha.114.304627] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE The deficiency of very low-density lipoprotein receptor resulted in Wnt signaling activation and neovascularization in the retina. The present study sought to determine whether the very low-density lipoprotein receptor extracellular domain (VLN) is responsible for the inhibition of Wnt signaling in ocular tissues. APPROACH AND RESULTS A plasmid expressing the soluble VLN was encapsulated with poly(lactide-co-glycolide acid) to form VLN nanoparticles (VLN-NP). Nanoparticles containing a plasmid expressing the low-density lipoprotein receptor extracellular domain nanoparticle were used as negative control. MTT, modified Boyden chamber, and Matrigel (™) assays were used to evaluate the inhibitory effect of VLN-NP on Wnt3a-stimulated endothelial cell proliferation, migration, and tube formation. Vldlr(-/-) mice, oxygen-induced retinopathy, and alkali burn-induced corneal neovascularization models were used to evaluate the effect of VLN-NP on ocular neovascularization. Wnt reporter mice (BAT-gal), Western blotting, and luciferase assay were used to evaluate Wnt pathway activity. Our results showed that VLN-NP specifically inhibited Wnt3a-induced endothelial cell proliferation, migration, and tube formation. Intravitreal injection of VLN-NP inhibited abnormal neovascularization in Vldlr(-/-), oxygen-induced retinopathy, and alkali burn-induced corneal neovascularization models, compared with low-density lipoprotein receptor extracellular domain nanoparticle. VLN-NP significantly inhibited the phosphorylation of low-density lipoprotein receptor-related protein 6, the accumulation of β-catenin, and the expression of vascular endothelial growth factor in vivo and in vitro. CONCLUSIONS Taken together, these results suggest that the soluble VLN is a negative regulator of the Wnt pathway and has antiangiogenic activities. Nanoparticle-mediated expression of VLN may thus represent a novel therapeutic approach to treat pathological ocular angiogenesis and potentially other vascular diseases affected by Wnt signaling.
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Affiliation(s)
- Zhongxiao Wang
- From the Department of Ophthalmology, Shanghai First People's Hospital Affiliated to Shanghai Jiaotong University, Shanghai, China (Z.W., X.X.); Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City (Z.W., R.C., K.L., L.D., J.-x.M.); Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora (P.T., U.B.K.); Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China (L.D.); and Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, MA (J.C.)
| | - Rui Cheng
- From the Department of Ophthalmology, Shanghai First People's Hospital Affiliated to Shanghai Jiaotong University, Shanghai, China (Z.W., X.X.); Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City (Z.W., R.C., K.L., L.D., J.-x.M.); Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora (P.T., U.B.K.); Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China (L.D.); and Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, MA (J.C.)
| | - Kyungwon Lee
- From the Department of Ophthalmology, Shanghai First People's Hospital Affiliated to Shanghai Jiaotong University, Shanghai, China (Z.W., X.X.); Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City (Z.W., R.C., K.L., L.D., J.-x.M.); Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora (P.T., U.B.K.); Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China (L.D.); and Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, MA (J.C.)
| | - Puneet Tyagi
- From the Department of Ophthalmology, Shanghai First People's Hospital Affiliated to Shanghai Jiaotong University, Shanghai, China (Z.W., X.X.); Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City (Z.W., R.C., K.L., L.D., J.-x.M.); Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora (P.T., U.B.K.); Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China (L.D.); and Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, MA (J.C.)
| | - Lexi Ding
- From the Department of Ophthalmology, Shanghai First People's Hospital Affiliated to Shanghai Jiaotong University, Shanghai, China (Z.W., X.X.); Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City (Z.W., R.C., K.L., L.D., J.-x.M.); Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora (P.T., U.B.K.); Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China (L.D.); and Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, MA (J.C.)
| | - Uday B Kompella
- From the Department of Ophthalmology, Shanghai First People's Hospital Affiliated to Shanghai Jiaotong University, Shanghai, China (Z.W., X.X.); Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City (Z.W., R.C., K.L., L.D., J.-x.M.); Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora (P.T., U.B.K.); Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China (L.D.); and Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, MA (J.C.)
| | - Jing Chen
- From the Department of Ophthalmology, Shanghai First People's Hospital Affiliated to Shanghai Jiaotong University, Shanghai, China (Z.W., X.X.); Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City (Z.W., R.C., K.L., L.D., J.-x.M.); Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora (P.T., U.B.K.); Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China (L.D.); and Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, MA (J.C.)
| | - Xun Xu
- From the Department of Ophthalmology, Shanghai First People's Hospital Affiliated to Shanghai Jiaotong University, Shanghai, China (Z.W., X.X.); Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City (Z.W., R.C., K.L., L.D., J.-x.M.); Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora (P.T., U.B.K.); Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China (L.D.); and Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, MA (J.C.).
| | - Jian-Xing Ma
- From the Department of Ophthalmology, Shanghai First People's Hospital Affiliated to Shanghai Jiaotong University, Shanghai, China (Z.W., X.X.); Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City (Z.W., R.C., K.L., L.D., J.-x.M.); Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora (P.T., U.B.K.); Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China (L.D.); and Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, MA (J.C.).
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DiBattista AM, Dumanis SB, Song JM, Bu G, Weeber E, Rebeck GW, Hoe HS. Very low density lipoprotein receptor regulates dendritic spine formation in a RasGRF1/CaMKII dependent manner. Biochim Biophys Acta 2015; 1853:904-17. [PMID: 25644714 DOI: 10.1016/j.bbamcr.2015.01.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 12/20/2014] [Accepted: 01/22/2015] [Indexed: 11/17/2022]
Abstract
Very Low Density Lipoprotein Receptor (VLDLR) is an apolipoprotein E receptor involved in synaptic plasticity, learning, and memory. However, it is unknown how VLDLR can regulate synaptic and cognitive function. In the present study, we found that VLDLR is present at the synapse both pre- and post-synaptically. Overexpression of VLDLR significantly increases, while knockdown of VLDLR decreases, dendritic spine number in primary hippocampal cultures. Additionally, knockdown of VLDLR significantly decreases synaptophysin puncta number while differentially regulating cell surface and total levels of glutamate receptor subunits. To identify the mechanism by which VLDLR induces these synaptic effects, we investigated whether VLDLR affects dendritic spine formation through the Ras signaling pathway, which is involved in spinogenesis and neurodegeneration. Interestingly, we found that VLDLR interacts with RasGRF1, a Ras effector, and knockdown of RasGRF1 blocks the effect of VLDLR on spinogenesis. Moreover, we found that VLDLR did not rescue the deficits induced by the absence of Ras signaling proteins CaMKIIα or CaMKIIβ. Taken together, our results suggest that VLDLR requires RasGRF1/CaMKII to alter dendritic spine formation.
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Affiliation(s)
| | - Sonya B Dumanis
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC 20057, USA; Max Delbreuck Center for Molecular Medicine, Berlin, Germany
| | - Jung Min Song
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Edwin Weeber
- Department of Molecular Pharmacology and Physiology, USF Health Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33613, USA
| | - G William Rebeck
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Hyang-Sook Hoe
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC 20057, USA; Department of Neurology, Georgetown University Medical Center, Washington, DC 20057, USA.
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Hirota Y, Kubo KI, Katayama KI, Honda T, Fujino T, Yamamoto TT, Nakajima K. Reelin receptors ApoER2 and VLDLR are expressed in distinct spatiotemporal patterns in developing mouse cerebral cortex. J Comp Neurol 2014; 523:463-78. [PMID: 25308109 DOI: 10.1002/cne.23691] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 10/07/2014] [Accepted: 10/07/2014] [Indexed: 01/31/2023]
Abstract
In mammalian developing brain, neuronal migration is regulated by a variety of signaling cascades, including Reelin signaling. Reelin is a glycoprotein that is mainly secreted by Cajal-Retzius neurons in the marginal zone, playing essential roles in the formation of the layered neocortex via its receptors, apolipoprotein E receptor 2 (ApoER2) and very low density lipoprotein receptor (VLDLR). However, the precise mechanisms by which Reelin signaling controls the neuronal migration process remain unclear. To gain insight into how Reelin signaling controls individual migrating neurons, we generated monoclonal antibodies against ApoER2 and VLDLR and examined the localization of Reelin receptors in the developing mouse cerebral cortex. Immunohistochemical analyses revealed that VLDLR is localized to the distal portion of leading processes in the marginal zone (MZ), whereas ApoER2 is mainly localized to neuronal processes and the cell membranes of multipolar cells in the multipolar cell accumulation zone (MAZ). These different expression patterns may contribute to the distinct actions of Reelin on migrating neurons during both the early and late migratory stages in the developing cerebral cortex.
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Affiliation(s)
- Yuki Hirota
- Department of Anatomy, Keio University School of Medicine, Tokyo, 160-8582, Japan
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Kizhakkedath P, Loregger A, John A, Bleijlevens B, Al-Blooshi AS, Al-Hosani AH, Al-Nuaimi AM, Al-Gazali L, Zelcer N, Ali BR. Impaired trafficking of the very low density lipoprotein receptor caused by missense mutations associated with dysequilibrium syndrome. Biochim Biophys Acta 2014; 1843:2871-7. [PMID: 25173816 DOI: 10.1016/j.bbamcr.2014.08.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 08/18/2014] [Accepted: 08/22/2014] [Indexed: 02/08/2023]
Abstract
Dysequilibrium syndrome (DES, OMIM 224050) is a genetically heterogeneous condition that combines autosomal recessive non-progressive cerebellar ataxia with mental retardation. The subclass dysequilibrium syndrome type 1 (CAMRQ1) has been attributed to mutations in the VLDLR gene encoding the very low density lipoprotein receptor (VLDLR). This receptor is involved in the Reelin signaling pathway that guides neuronal migration in the cerebral cortex and cerebellum. Three missense mutations (c.1459G>T; p.D487Y, c.1561G>C; p.D521H and c.2117G>T; p.C706F) have been previously identified in VLDLR gene in patients with DES. However, the functional implications of those mutations are not known and therefore we undertook detailed functional analysis to elucidate the cellular mechanisms underlying their pathogenicity. The mutations have been generated by site-directed mutagenesis and then expressed in cultured cell lines. Confocal microscopy and biochemical analysis have been employed to examine the subcellular localization and functional activities of the mutated proteins relative to wild type. Our results indicate that the three missense mutations lead to defective intracellular trafficking and ER retention of the mutant VLDLR protein. This trafficking impairment prevents the mutants from reaching the plasma membrane and binding exogenous Reelin, the initiating event in Reelin signaling. Collectively, our results provide evidence that ER quality control is involved in the functional inactivation and underlying pathogenicity of these DES-associated mutations in the VLDLR.
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Nguyen A, Tao H, Metrione M, Hajri T. Very low density lipoprotein receptor ( VLDLR) expression is a determinant factor in adipose tissue inflammation and adipocyte-macrophage interaction. J Biol Chem 2013; 289:1688-703. [PMID: 24293365 DOI: 10.1074/jbc.m113.515320] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Obesity is associated with adipose tissue remodeling, characterized by adipocyte hypertrophy and macrophage infiltration. Previously, we have shown that very low density lipoprotein receptor (VLDLR) is virtually absent in preadipocytes but is strongly induced during adipogenesis and actively participates in adipocyte hypertrophy. In this study, we investigated the role of VLDLR in adipose tissue inflammation and adipocyte-macrophage interactions in wild type and VLDLR-deficient mice fed a high fat diet. The results show that VLDLR deficiency reduced high fat diet-induced inflammation and endoplasmic reticulum (ER) stress in adipose tissue in conjunction with reduced macrophage infiltration, especially those expressing pro-inflammatory markers. In adipocyte culture, VLDLR deficiency prevented adipocyte hypertrophy and strongly reduced VLDL-induced ER stress and inflammation. Likewise, cultures of primary peritoneal macrophages show that VLDLR deficiency reduced lipid accumulation and inflammation but did not alter chemotactic response of macrophages to adipocyte signals. Moreover, VLDLR deficiency tempered the synergistic inflammatory interactions between adipocytes and macrophages in a co-culture system. Collectively, these results show that VLDLR contributes to adipose tissue inflammation and mediates VLDL-induced lipid accumulation and induction of inflammation and ER stress in adipocytes and macrophages.
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Affiliation(s)
- Andrew Nguyen
- From the Department of Surgery, Hackensack University Medical Center, Hackensack, New Jersey 07601 and
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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: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Magome T, Hattori T, Taniguchi M, Ishikawa T, Miyata S, Yamada K, Takamura H, Matsuzaki S, Ito A, Tohyama M, Katayama T. XLMR protein related to neurite extension (Xpn/KIAA2022) regulates cell-cell and cell-matrix adhesion and migration. Neurochem Int 2013; 63:561-9. [PMID: 24071057 DOI: 10.1016/j.neuint.2013.09.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 09/07/2013] [Accepted: 09/13/2013] [Indexed: 11/22/2022]
Abstract
X-linked mental retardation (XLMR) is a common cause of moderate to severe intellectual disability in males. XLMR protein related to neurite extension (Xpn, also known as KIAA2022) has been implicated as a gene responsible for XLMR in humans. Although Xpn is highly expressed in the developing brain and is involved in neurite outgrowth in PC12 cells and neurons, little is known about the functional role of Xpn. Here, we show that Xpn regulates cell-cell and cell-matrix adhesion and migration in PC12 cells. Xpn knockdown enhanced cell-cell and cell-matrix adhesion mediated by N-cadherin and β1-integrin, respectively. N-Cadherin and β1-integrin expression at the mRNA and protein levels was significantly increased in Xpn knockdown PC12 cells. Furthermore, overexpressed Xpn protein was strongly expressed in the nuclei of PC12 and 293T cells. Finally, depletion of Xpn perturbed cellular migration by enhancing N-cadherin and β1-integrin expression in a PC12 cell wound healing assay. We conclude that Xpn regulates cell-cell and cell-matrix adhesion and cellular migration by regulating the expression of adhesion molecules.
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Urban D, Pöss J, Böhm M, Laufs U. Targeting the proprotein convertase subtilisin/kexin type 9 for the treatment of dyslipidemia and atherosclerosis. J Am Coll Cardiol 2013; 62:1401-8. [PMID: 23973703 DOI: 10.1016/j.jacc.2013.07.056] [Citation(s) in RCA: 214] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 07/18/2013] [Accepted: 07/23/2013] [Indexed: 01/07/2023]
Abstract
Hypercholesterolemia is a major risk factor for cardiovascular diseases, increasing the incidence of myocardial infarction and death. Statin-induced lowering of low-density lipoprotein cholesterol (LDL-C) reduces cardiovascular morbidity and mortality. However, many individuals treated with statins do not achieve their target levels of LDL-C, and thus, LDL-associated residual risk remains. Gain-of-function mutations of the proprotein convertase subtilisin/kexin type 9 (PCSK9) are associated with hypercholesterolemia and increased risk of cardiovascular events. Conversely, loss-of-function mutations are linked to low plasma LDL-C levels and a reduction of cardiovascular risk without known unwanted effects on individual health. Experimental studies have revealed that PCSK9 reduces the hepatic uptake of LDL-C by increasing the endosomal and lysosomal degradation of LDL receptors (LDLR). Low intracellular cholesterol levels in response to statin treatment activate the sterol regulatory element-binding protein-2 (SREBP-2), resulting in coexpression of LDLR and PCSK9. Although this self-regulatory mechanism contributes to maintain cholesterol homeostasis preventing excessive cholesterol uptake, it may limit the therapeutic effect of statins. A number of clinical studies have demonstrated that inhibition of PCSK9 alone and in addition to statins potently reduces serum LDL-C concentrations. Moreover, experimental studies indicate that PCSK9 might accelerate atherosclerosis by promoting inflammation, endothelial dysfunction, and hypertension by mechanisms independent of the LDLR. Further research is needed to characterize the potential therapeutic and to rule out unwanted off-target effects of PCSK9 inhibition. In this review we elucidate the role of PCSK9 in lipid homeostasis, highlight the impact of PCSK9 on atherosclerosis, and summarize current therapeutic strategies targeting PCSK9.
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Affiliation(s)
- Daniel Urban
- Klinik für Innere Medizin III, Kardiologie, Angiologie und Internistische Intensivmedizin, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany.
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Azmanov DN, Chamova T, Tankard R, Gelev V, Bynevelt M, Florez L, Tzoneva D, Zlatareva D, Guergueltcheva V, Bahlo M, Tournev I, Kalaydjieva L. Challenges of diagnostic exome sequencing in an inbred founder population. Mol Genet Genomic Med 2013; 1:71-6. [PMID: 24498604 PMCID: PMC3865571 DOI: 10.1002/mgg3.7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 03/06/2013] [Accepted: 03/08/2013] [Indexed: 11/17/2022] Open
Abstract
Exome sequencing was used as a diagnostic tool in a Roma/Gypsy family with three subjects (one deceased) affected by lissencephaly with cerebellar hypoplasia (LCH), a clinically and genetically heterogeneous diagnostic category. Data analysis identified high levels of unreported inbreeding, with multiple rare/novel “deleterious” variants occurring in the homozygous state in the affected individuals. Step-wise filtering was facilitated by the inclusion of parental samples in the analysis and the availability of ethnically matched control exome data. We identified a novel mutation, p.Asp487Tyr, in the VLDLR gene involved in the Reelin developmental pathway and associated with a rare form of LCH, the Dysequilibrium Syndrome. p.Asp487Tyr is the third reported missense mutation in this gene and the first example of a change affecting directly the functionally crucial β-propeller domain. An unexpected additional finding was a second unique mutation (p.Asn494His) with high scores of predicted pathogenicity in KCNV2, a gene implicated in a rare eye disorder, retinal cone dystrophy type 3B. This result raised diagnostic and counseling challenges that could be resolved through mutation screening of a large panel of healthy population controls. The strategy and findings of this study may inform the search for new disease mutations in the largest European genetic isolate.
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Affiliation(s)
- Dimitar N Azmanov
- Laboratory for Molecular Genetics, Centre for Medical Research/Western Australian Institute for Medical Research, The University of Western Australia Perth, WA, Australia
| | | | - Rick Tankard
- Bioinformatics Division, The Walter and Eliza Hall Institute Melbourne, VIC, Australia
| | - Vladimir Gelev
- Faculty of Chemistry and Pharmacy, Sofia University Sofia, Bulgaria
| | - Michael Bynevelt
- Department of Surgery, School of Medicine, The University of Western Australia Perth, WA, Australia ; Neurological Intervention and Imaging Service (WA), Sir Charles Gairdner Hospital Perth, WA, Australia
| | - Laura Florez
- Laboratory for Molecular Genetics, Centre for Medical Research/Western Australian Institute for Medical Research, The University of Western Australia Perth, WA, Australia
| | - Dochka Tzoneva
- Department of Anesthesiology and Intensive Care, University Hospital "Alexandrovska" Sofia, Bulgaria
| | - Dora Zlatareva
- Department of Diagnostic Imaging, University Hospital "Alexandrovska" Sofia, Bulgaria
| | | | - Melanie Bahlo
- Bioinformatics Division, The Walter and Eliza Hall Institute Melbourne, VIC, Australia ; Department of Mathematics and Statistics, The University of Melbourne Melbourne, VIC, Australia
| | - Ivailo Tournev
- Department of Neurology, Medical University Sofia, Bulgaria ; Department of Cognitive Science and Psychology, New Bulgarian University Sofia, Bulgaria
| | - Luba Kalaydjieva
- Laboratory for Molecular Genetics, Centre for Medical Research/Western Australian Institute for Medical Research, The University of Western Australia Perth, WA, Australia
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Chen T, Wu F, Chen FM, Tian J, Qu S. Variations of very low-density lipoprotein receptor subtype expression in gastrointestinal adenocarcinoma cells with various differentiations. World J Gastroenterol 2005; 11:2817-21. [PMID: 15884130 PMCID: PMC4305924 DOI: 10.3748/wjg.v11.i18.2817] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: This study is aimed at investigating the expression and possible significances of very low-density lipoprotein receptor (VLDLR) subtypes in gastroenteric adenocarcinoma tissues and cells with various differentiations.
METHODS: Thirty-one cases of gastroenteric carcinoma/adjacent normal tissues were enrolled in the study, which were diagnosed and classified by the clinicopathological diagnosis. The expression of VLDLR subtypes was detected in gastroenteric carcinoma/adjacent normal tissues and three various differentiated human gastric adenocarcinoma cell lines (MKN28, SGC7901 and MKN45) by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis.
RESULTS: Two VLDLR subtypes, namely, type II VLDLR and type I VLDLR, were found to express changes in gastroenteric carcinoma tissues, their adjacent normal tissue, and gastric adenocarcinoma cell lines as well. Type II VLDLR is predominantly expressed in poorly- or moderately-differentiated gastroenteric carcinoma tissues and gastric adenocarcinoma cell lines, whereas type I VLDLR is mainly detected in well-differentiated intestinal carcinoma tissues and gastric adenocarcinoma cells compared with the adjacent normal tissues.
CONCLUSION: The results suggested that the variations of the VLDLR subtype expression might be correlated with the progress and differentiation of gastroenteric carcinoma.
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Affiliation(s)
- Tao Chen
- Department of Biochemistry and Molecular Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China
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