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Smith BC, Silvers R. 1H, 13C, and 15N resonance assignments of the La Motif of the human La-related protein 1. BIOMOLECULAR NMR ASSIGNMENTS 2024; 18:111-118. [PMID: 38691336 DOI: 10.1007/s12104-024-10176-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 04/22/2024] [Indexed: 05/03/2024]
Abstract
Human La-related protein 1 (HsLARP1) is involved in post-transcriptional regulation of certain 5' terminal oligopyrimidine (5'TOP) mRNAs as well as other mRNAs and binds to both the 5'TOP motif and the 3'-poly(A) tail of certain mRNAs. HsLARP1 is heavily involved in cell proliferation, cell cycle defects, and cancer, where HsLARP1 is significantly upregulated in malignant cells and tissues. Like all LARPs, HsLARP1 contains a folded RNA binding domain, the La motif (LaM). Our current understanding of post-transcriptional regulation that emanates from the intricate molecular framework of HsLARP1 is currently limited to small snapshots, obfuscating our understanding of the full picture on HsLARP1 functionality in post-transcriptional events. Here, we present the nearly complete resonance assignment of the LaM of HsLARP1, providing a significant platform for future NMR spectroscopic studies.
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Affiliation(s)
- Benjamin C Smith
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, FL, 32306, USA
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, 32306, USA
| | - Robert Silvers
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, FL, 32306, USA.
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, 32306, USA.
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2
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Smith BC, Silvers R. NMR Resonance Assignment of the LA Motif of Human LA-Related Protein 1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.09.539749. [PMID: 37214987 PMCID: PMC10197598 DOI: 10.1101/2023.05.09.539749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Human La-related protein 1 (HsLARP1) is involved in post-transcriptional regulation of certain 5' s terminal oligopyrimidine (5'TOP) mRNAs as well as other mRNAs and binds to both the 5'TOP motif and the 3'-poly(A) tail of certain mRNAs. HsLARP1 is heavily involved in cell proliferation, cell cycle defects, and cancer, where HsLARP1 is significantly upregulated in malignant cells and tissues. Like all LARPs, HsLARP1 contains a folded RNA binding domain, the La motif (LaM). Our current understanding of post-transcriptional regulation that emanates from the intricate molecular framework of HsLARP1 is currently limited to small snapshots, obfuscating our understanding of the full picture on HsLARP1 functionality in post-transcriptional events. Here, we present the nearly complete resonance assignment of the LaM of HsLARP1, providing a significant platform for future NMR spectroscopic studies.
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3
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Long X, Liu X, Deng T, Chen J, Lan J, Zhang S, Zhou M, Guo D, Zhou J. LARP6 suppresses colorectal cancer progression through ZNF267/SGMS2-mediated imbalance of sphingomyelin synthesis. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2023; 42:33. [PMID: 36691044 PMCID: PMC9872320 DOI: 10.1186/s13046-023-02605-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 01/18/2023] [Indexed: 01/25/2023]
Abstract
BACKGROUND With increasing incidence and mortality, colorectal cancer (CRC) seriously endangers human health. LARP6, a member of La-related protein (LARP) family, is a RNA binding protein and probably associates with CRC progression, but its specific roles and mechanisms in CRC still remain unknown. METHOD Quantitative real-time PCR (qPCR), western blot, and immunohistochemistry were employed to examine LARP6 expression in CRC tissues. Using the stable LARP6 overexpression or interference CRC cell lines, the effect of LARP6 on CRC progression were evaluated. High-throughput RNA immunoprecipitation sequencing (RIP-seq) and a series of relevant experiments were conducted to explain how LARP6 functions. SPSS software was used for statistical analysis. RESULT In this study, we found that LARP6 expression is downregulated in CRC and correlates with patients' overall survival and relapse-free survival. Furthermore, altered LARP6 expression influences CRC cells invasion and metastasis. Mechanically, we discovered that LARP6 bind ZNF267 mRNA and regulated its stability and translation. LARP6 inhibited expression of SGMS2, a downstream target of ZNF267, resulting in ceramide and sphingomyelin imbalance in CRC cells. Interestingly, LARP6 also enhances autophagy activity of CRC cells, and the effect was at least partially determined by the inhibition of SGMS2-mediated sphingomyelin synthesis. CONCLUSION Our study showed how LARP6/ZNF267/SGMS2 axis influence CRC progression, which contributes to further understanding of the molecular mechanisms underlying CRC development.
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Affiliation(s)
- Xiaoli Long
- grid.284723.80000 0000 8877 7471Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 China ,grid.284723.80000 0000 8877 7471Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 China
| | - Xunhua Liu
- grid.284723.80000 0000 8877 7471Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 China ,grid.284723.80000 0000 8877 7471Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 China
| | - Ting Deng
- Department of Pathology, YunFu People’s Hospital, Yunfu, 527300 China
| | - Jianxiong Chen
- grid.284723.80000 0000 8877 7471Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 China ,grid.284723.80000 0000 8877 7471Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 China
| | - Jiawen Lan
- grid.284723.80000 0000 8877 7471Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 China ,grid.284723.80000 0000 8877 7471Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 China
| | - Sijing Zhang
- grid.284723.80000 0000 8877 7471Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 China
| | - Miao Zhou
- grid.284723.80000 0000 8877 7471Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 China
| | - Dan Guo
- grid.284723.80000 0000 8877 7471Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 China
| | - Jun Zhou
- grid.284723.80000 0000 8877 7471Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 China ,grid.284723.80000 0000 8877 7471Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 China ,Department of Pathology, YunFu People’s Hospital, Yunfu, 527300 China
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Laverty KU, Jolma A, Pour SE, Zheng H, Ray D, Morris Q, Hughes TR. PRIESSTESS: interpretable, high-performing models of the sequence and structure preferences of RNA-binding proteins. Nucleic Acids Res 2022; 50:e111. [PMID: 36018788 DOI: 10.1093/nar/gkac694] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 07/22/2022] [Accepted: 08/03/2022] [Indexed: 12/23/2022] Open
Abstract
Modelling both primary sequence and secondary structure preferences for RNA binding proteins (RBPs) remains an ongoing challenge. Current models use varied RNA structure representations and can be difficult to interpret and evaluate. To address these issues, we present a universal RNA motif-finding/scanning strategy, termed PRIESSTESS (Predictive RBP-RNA InterpretablE Sequence-Structure moTif regrESSion), that can be applied to diverse RNA binding datasets. PRIESSTESS identifies dozens of enriched RNA sequence and/or structure motifs that are subsequently reduced to a set of core motifs by logistic regression with LASSO regularization. Importantly, these core motifs are easily visualized and interpreted, and provide a measure of RBP secondary structure specificity. We used PRIESSTESS to interrogate new HTR-SELEX data for 23 RBPs with diverse RNA binding modes and captured known primary sequence and secondary structure preferences for each. Moreover, when applying PRIESSTESS to 144 RBPs across 202 RNA binding datasets, 75% showed an RNA secondary structure preference but only 10% had a preference besides unpaired bases, suggesting that most RBPs simply recognize the accessibility of primary sequences.
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Affiliation(s)
- Kaitlin U Laverty
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Arttu Jolma
- Department of Molecular Genetics, University of Toronto, Toronto, Canada.,Donnelly Centre, University of Toronto, Toronto, Canada
| | - Sara E Pour
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Hong Zheng
- Donnelly Centre, University of Toronto, Toronto, Canada
| | - Debashish Ray
- Donnelly Centre, University of Toronto, Toronto, Canada
| | - Quaid Morris
- Department of Molecular Genetics, University of Toronto, Toronto, Canada.,Computational and Systems Biology, Memorial Sloan Kettering Cancer Center, New York, USA
| | - Timothy R Hughes
- Department of Molecular Genetics, University of Toronto, Toronto, Canada.,Donnelly Centre, University of Toronto, Toronto, Canada
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Dong M, Zhang L, Wu P, Feng L, Jiang W, Liu Y, Kuang S, Li S, Mi H, Tang L, Zhou X. Dietary protein levels changed the hardness of muscle by acting on muscle fiber growth and the metabolism of collagen in sub-adult grass carp (Ctenopharyngodon idella). J Anim Sci Biotechnol 2022; 13:109. [PMID: 36002862 PMCID: PMC9404606 DOI: 10.1186/s40104-022-00747-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 06/22/2022] [Indexed: 01/24/2023] Open
Abstract
Background Nutrient regulation has been proven to be an effective way to improve the flesh quality in fish. As a necessary nutrient for fish growth, protein accounts for the highest proportion in the fish diet and is expensive. Although our team found that the effect of protein on the muscle hardness of grass carp was probably related to an increased collagen content, the mechanism for this effect has not been deeply explored. Moreover, few studies have explored the protein requirements of sub-adult grass crap (Ctenopharyngodon idella). Therefore, the effects of different dietary protein levels on the growth performance, nutritional value, muscle hardness, muscle fiber growth, collagen metabolism and related molecule expression in grass carp were investigated. Methods A total of 450 healthy grass carp (721.16 ± 1.98 g) were selected and assigned randomly to six experimental groups with three replicates each (n = 25/replicate), and were fed six diets with 15.91%, 19.39%, 22.10%, 25.59%, 28.53% and 31.42% protein for 60 d. Results Appropriate levels of dietary protein increased the feed intake, percentage weight gain, specific growth rate, body composition, unsaturated fatty acid content in muscle, partial free amino acid content in muscle, and muscle hardness of grass carp. These protein levels also increased the muscle fiber density, the frequency of new muscle fibers, the contents of collagen and IGF-1, and the enzyme activities of prolyl 4-hydroxylases and lysyloxidase, and decreased the activity of matrix metalloproteinase-2. At the molecular level, the optimal dietary protein increased collagen type I α1 (Colα1), Colα2, PI3K, Akt, S6K1, La ribonucleoprotein domain family member 6a (LARP6a), TGF-β1, Smad2, Smad4, Smad3, tissue inhibitor of metalloproteinase-2, MyoD, Myf5, MyoG and MyHC relative mRNA levels. The levels of the myostatin-1 and myostatin-2 genes were downregulated, and the protein expression levels of p-Smad2, Smad2, Smad4, p-Akt, Akt, LARP6 and Smad3 were increased. Conclusions The appropriate levels of dietary protein promoted the growth of sub-adult grass carp and improved muscle hardness by promoting the growth of muscle fibers, improving collagen synthesis and depressing collagen degradation. In addition, the dietary protein requirements of sub-adult grass carp were 26.21% and 24.85% according to the quadratic regression analysis of growth performance (SGR) and the muscle hardness (collagen content), respectively. Supplementary Information The online version contains supplementary material available at 10.1186/s40104-022-00747-7.
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Affiliation(s)
- Min Dong
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130, China.,Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China.,Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan Province, Sichuan, 611130, China
| | - Lu Zhang
- Healthy Aquaculture Key Laboratory of Sichuan Province, Tongwei Co., Ltd., Chengdu China, Sichuan, 610041, China
| | - Pei Wu
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130, China.,Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China.,Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan Province, Sichuan, 611130, China
| | - Lin Feng
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130, China.,Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China.,Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan Province, Sichuan, 611130, China
| | - Weidan Jiang
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130, China.,Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China.,Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan Province, Sichuan, 611130, China
| | - Yang Liu
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130, China.,Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China.,Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan Province, Sichuan, 611130, China
| | - Shengyao Kuang
- Animal Nutrition Institute, Sichuan Academy of Animal Science, Sichuan Animtech Feed Co. Ltd, Chengdu, 610066, China
| | - Shuwei Li
- Animal Nutrition Institute, Sichuan Academy of Animal Science, Sichuan Animtech Feed Co. Ltd, Chengdu, 610066, China
| | - Haifeng Mi
- Healthy Aquaculture Key Laboratory of Sichuan Province, Tongwei Co., Ltd., Chengdu China, Sichuan, 610041, China
| | - Ling Tang
- Animal Nutrition Institute, Sichuan Academy of Animal Science, Sichuan Animtech Feed Co. Ltd, Chengdu, 610066, China
| | - Xiaoqiu Zhou
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130, China. .,Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China. .,Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan Province, Sichuan, 611130, China.
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Morin C, Moyret-Lalle C, Mertani HC, Diaz JJ, Marcel V. Heterogeneity and dynamic of EMT through the plasticity of ribosome and mRNA translation. Biochim Biophys Acta Rev Cancer 2022; 1877:188718. [PMID: 35304296 DOI: 10.1016/j.bbcan.2022.188718] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/02/2022] [Accepted: 03/11/2022] [Indexed: 02/06/2023]
Abstract
Growing evidence exposes translation and its translational machinery as key players in establishing and maintaining physiological and pathological biological processes. Examining translation may not only provide new biological insight but also identify novel innovative therapeutic targets in several fields of biology, including that of epithelial-to-mesenchymal transition (EMT). EMT is currently considered as a dynamic and reversible transdifferentiation process sustaining the transition from an epithelial to mesenchymal phenotype, known to be mainly driven by transcriptional reprogramming. However, it seems that the characterization of EMT plasticity is challenging, relying exclusively on transcriptomic and epigenetic approaches. Indeed, heterogeneity in EMT programs was reported to depend on the biological context. Here, by reviewing the involvement of translational control, translational machinery and ribosome biogenesis characterizing the different types of EMT, from embryonic and adult physiological to pathological contexts, we discuss the added value of integrating translational control and its machinery to depict the heterogeneity and dynamics of EMT programs.
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Affiliation(s)
- Chloé Morin
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon, Université Claude Bernard Lyon 1, Centre Léon Bérard, F-69373 Lyon Cedex 08, France; Institut Convergence PLAsCAN, 69373 Lyon cedex 08, France; DevWeCan Labex Laboratory, 69373 Lyon cedex 08, France
| | - Caroline Moyret-Lalle
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon, Université Claude Bernard Lyon 1, Centre Léon Bérard, F-69373 Lyon Cedex 08, France; Institut Convergence PLAsCAN, 69373 Lyon cedex 08, France; DevWeCan Labex Laboratory, 69373 Lyon cedex 08, France
| | - Hichem C Mertani
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon, Université Claude Bernard Lyon 1, Centre Léon Bérard, F-69373 Lyon Cedex 08, France; Institut Convergence PLAsCAN, 69373 Lyon cedex 08, France; DevWeCan Labex Laboratory, 69373 Lyon cedex 08, France
| | - Jean-Jacques Diaz
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon, Université Claude Bernard Lyon 1, Centre Léon Bérard, F-69373 Lyon Cedex 08, France; Institut Convergence PLAsCAN, 69373 Lyon cedex 08, France; DevWeCan Labex Laboratory, 69373 Lyon cedex 08, France
| | - Virginie Marcel
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon, Université Claude Bernard Lyon 1, Centre Léon Bérard, F-69373 Lyon Cedex 08, France; Institut Convergence PLAsCAN, 69373 Lyon cedex 08, France; DevWeCan Labex Laboratory, 69373 Lyon cedex 08, France.
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7
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Shi R, Zhang Z, Zhu A, Xiong X, Zhang J, Xu J, Sy MS, Li C. Targeting Type I Collagen for Cancer Treatment. Int J Cancer 2022; 151:665-683. [PMID: 35225360 DOI: 10.1002/ijc.33985] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 11/07/2022]
Abstract
Collagen is the most abundant protein in animals. Interactions between tumor cells and collagen influence every step of tumor development. Type I collagen is the main fibrillar collagen in the extracellular matrix and is frequently up-regulated during tumorigenesis. The binding of type I collagen to its receptors on tumor cells promotes tumor cell proliferation, epithelial-mesenchymal transition, and metastasis. Type I collagen also regulates the efficacy of tumor therapies, such as chemotherapy, radiotherapy, and immunotherapy. Furthermore, type I collagen fragments are diagnostic markers of metastatic tumors and have prognostic value. Inhibition of type I collagen synthesis has been reported to have anti-tumor effects in animal models. However, collagen has also been shown to possess anti-tumor activity. Therefore, the roles that type I collagen plays in tumor biology are complex and tumor type-dependent. In this review, we discuss the expression and regulation of synthesis of type I collagen, as well as the role up-regulated type I collagen plays in various stages of cancer progression. We also discuss the role of collagen in tumor therapy. Finally, we highlight several recent approaches targeting type I collagen for cancer treatment. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Run Shi
- Affiliated Cancer Hospital & Institute of Guangzhou Medical University, State Key Laboratory of Respiratory Disease, Key Laboratory for Cell Homeostasis and Cancer Research of Guangdong High Education Institute, Guangzhou, China
| | - Zhe Zhang
- Affiliated Cancer Hospital & Institute of Guangzhou Medical University, State Key Laboratory of Respiratory Disease, Key Laboratory for Cell Homeostasis and Cancer Research of Guangdong High Education Institute, Guangzhou, China
| | - Ankai Zhu
- Affiliated Cancer Hospital & Institute of Guangzhou Medical University, State Key Laboratory of Respiratory Disease, Key Laboratory for Cell Homeostasis and Cancer Research of Guangdong High Education Institute, Guangzhou, China
| | - Xingxing Xiong
- Department of Operating Room, Jiangxi Cancer Hospital of Nanchang University, Nanchang, China
| | - Jie Zhang
- Affiliated Cancer Hospital & Institute of Guangzhou Medical University, State Key Laboratory of Respiratory Disease, Key Laboratory for Cell Homeostasis and Cancer Research of Guangdong High Education Institute, Guangzhou, China
| | - Jiang Xu
- Department of Stomatology, First Affiliated Hospital, School of Medicine, Shihezi University, Shihezi, China
| | - Man-Sun Sy
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Chaoyang Li
- Affiliated Cancer Hospital & Institute of Guangzhou Medical University, State Key Laboratory of Respiratory Disease, Key Laboratory for Cell Homeostasis and Cancer Research of Guangdong High Education Institute, Guangzhou, China
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8
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Stefanovic L, Gordon BH, Silvers R, Stefanovic B. Characterization of Sequence-Specific Binding of LARP6 to the 5' Stem-Loop of Type I Collagen mRNAs and Implications for Rational Design of Antifibrotic Drugs. J Mol Biol 2022; 434:167394. [PMID: 34896113 PMCID: PMC8752511 DOI: 10.1016/j.jmb.2021.167394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/29/2021] [Accepted: 12/01/2021] [Indexed: 02/01/2023]
Abstract
Excessive synthesis of type I collagen is a hallmark of fibrotic diseases. Binding of La-related protein 6 (LARP6) to the 5' stem-loop (5'SL) of collagen mRNAs regulates their translation leading to an unnaturally elevated rate of collagen biosynthesis in fibrosis. Previous work suggested that LARP6 needs two domains to form stable complex with 5'SL RNA, the La domain and the juxtaposed RNA recognition motif (RRM), jointly called the La-module. Here we describe that La domain of LARP6 is necessary and sufficient for recognition of 5'SL in RNA sequence specific manner. A three-amino-acid motif located in the flexible loop connecting the second α-helix to the β-sheet of the La domain, called the RNK-motif, is critical for binding. Mutation of any of these three amino acids abolishes the binding of the La domain to 5'SL. The major site of crosslinking of LARP6 to 5'SL RNA was mapped to this motif, as well. The RNK-motif is not found in other LARPs, which cannot bind 5'SL. Presence of RRM increases the stability of complex between La domain and 5'SL RNA and RRM domain does not make extensive contacts with 5'SL RNA. We propose a model in which the initial recognition of 5'SL by LARP6 is mediated by the RNK epitope and further stabilized by the RRM domain. This discovery suggests that the interaction between LARP6 and collagen mRNAs can be blocked by small molecules that target the RNK epitope and will help rational design of the LARP6 binding inhibitors as specific antifibrotic drugs.
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Affiliation(s)
- Lela Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
| | - Blaine H Gordon
- Department of Chemistry and Biochemistry, College of Arts and Sciences, Florida State University, Tallahassee, FL 32306, USA; Institute of Molecular Biophysics, College of Arts and Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Robert Silvers
- Department of Chemistry and Biochemistry, College of Arts and Sciences, Florida State University, Tallahassee, FL 32306, USA; Institute of Molecular Biophysics, College of Arts and Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Branko Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA.
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9
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Kim KI, Kwon CI, Lee JH, Kim CD, Yoon TJ. Inhibitory Effect of Mitoxantrone on Collagen Synthesis in Dermal Fibroblasts. Ann Dermatol 2022; 34:206-211. [PMID: 35721328 PMCID: PMC9171176 DOI: 10.5021/ad.2022.34.3.206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 12/21/2021] [Accepted: 02/14/2022] [Indexed: 11/21/2022] Open
Abstract
Background Fibroblasts produce collagen molecules that support the structure of the skin. The decrease and hypersynthesis of collagen causes skin problems such as skin atrophy, wrinkles and scars. Objective The purpose of this study is to investigate the mechanism of mitoxantrone on collagen synthesis in fibroblasts. Methods Cultured fibroblasts were treated with mitoxantrone, and then collagen synthesis was confirmed by reverse transcription-polymerase chain reaction and Western blot. Results Mitoxantrone inhibited the expression of type I collagen in fibroblasts at both the mRNA and protein levels. In the collagen gel contraction assay, mitoxantrone significantly inhibited gel contraction compared to the control group. Mitoxantrone inhibited transforming growth factor (TGF)-β-induced phosphorylation of SMAD3. Finally, mitoxantrone inhibited the expression of LARP6, an RNA-binding protein that regulates collagen mRNA stability. Conclusion These results suggest that mitoxantrone reduces collagen synthesis by inhibiting TGF-β/SMAD signaling and LARP6 expression in fibroblasts, which can be developed as a therapeutic agent for diseases caused by collagen hypersynthesis.
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Affiliation(s)
- Kyung-Il Kim
- Department of Dermatology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Korea
- Department of Medical Science, Chungnam National University School of Medicine, Daejeon, Korea
- Department of Dermatology, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Chang-Il Kwon
- Department of Dermatology, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
- Gyeongsang Institute of Health Sciences, Jinju, Korea
| | | | - Chang-Deok Kim
- Department of Dermatology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Korea
- Department of Medical Science, Chungnam National University School of Medicine, Daejeon, Korea
| | - Tae-Jin Yoon
- Department of Dermatology, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju, Korea
- Gyeongsang Institute of Health Sciences, Jinju, Korea
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10
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Ramirez-Perez FI, Woodford ML, Morales-Quinones M, Grunewald ZI, Cabral-Amador FJ, Yoshida T, Brenner DA, Manrique-Acevedo C, Martinez-Lemus LA, Chandrasekar B, Padilla J. Mutation of the 5'-untranslated region stem-loop mRNA structure reduces type I collagen deposition and arterial stiffness in male obese mice. Am J Physiol Heart Circ Physiol 2021; 321:H435-H445. [PMID: 34242094 PMCID: PMC8526337 DOI: 10.1152/ajpheart.00076.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Arterial stiffening, a characteristic feature of obesity and type 2 diabetes, contributes to the development and progression of cardiovascular diseases (CVD). Currently, no effective prophylaxis or therapeutics is available to prevent or treat arterial stiffening. A better understanding of the molecular mechanisms underlying arterial stiffening is vital to identify newer targets and strategies to reduce CVD burden. A major contributor to arterial stiffening is increased collagen deposition. In the 5'-untranslated regions of mRNAs encoding for type I collagen, an evolutionally conserved stem-loop (SL) structure plays an essential role in its stability and post-transcriptional regulation. Here, we show that feeding a high-fat/high-sucrose (HFHS) diet for 28 wk increases adiposity, insulin resistance, and blood pressure in male wild-type littermates. Moreover, arterial stiffness, assessed in vivo via aortic pulse wave velocity, and ex vivo using atomic force microscopy in aortic explants or pressure myography in isolated femoral and mesenteric arteries, was also increased in those mice. Notably, all these indices of arterial stiffness, along with collagen type I levels in the vasculature, were reduced in HFHS-fed mice harboring a mutation in the 5'SL structure, relative to wild-type littermates. This protective vascular phenotype in 5'SL-mutant mice did not associate with a reduction in insulin resistance or blood pressure. These findings implicate the 5'SL structure as a putative therapeutic target to prevent or reverse arterial stiffening and CVD associated with obesity and type 2 diabetes.NEW & NOTEWORTHY In the 5'-untranslated (UTR) regions of mRNAs encoding for type I collagen, an evolutionally conserved SL structure plays an essential role in its stability and posttranscriptional regulation. We demonstrate that a mutation of the SL mRNA structure in the 5'-UTR decreases collagen type I deposition and arterial stiffness in obese mice. Targeting this evolutionarily conserved SL structure may hold promise in the management of arterial stiffening and CVD associated with obesity and type 2 diabetes.
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Affiliation(s)
- Francisco I Ramirez-Perez
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri.,Department of Biomedical, Biological and Chemical Engineering, University of Missouri, Columbia, Missouri
| | - Makenzie L Woodford
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri.,Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | | | - Zachary I Grunewald
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri.,Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | | | - Tadashi Yoshida
- Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana
| | - David A Brenner
- School of Medicine, University of California-San Diego, La Jolla, California
| | - Camila Manrique-Acevedo
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri.,Division of Endocrinology and Metabolism, Department of Medicine, University of Missouri, Columbia, Missouri.,Harry S. Truman Memorial Veterans' Hospital, Columbia, Missouri
| | - Luis A Martinez-Lemus
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri.,Department of Biomedical, Biological and Chemical Engineering, University of Missouri, Columbia, Missouri.,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Bysani Chandrasekar
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri.,Harry S. Truman Memorial Veterans' Hospital, Columbia, Missouri.,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri.,Division of Cardiovascular Medicine, Department of Medicine, University of Missouri, Columbia, Missouri
| | - Jaume Padilla
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri.,Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
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11
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Stefanovic B, Stefanovic L, Manojlovic Z. Imaging of type I procollagen biosynthesis in cells reveals biogenesis in highly organized bodies; Collagenosomes. Matrix Biol Plus 2021; 12:100076. [PMID: 34278289 PMCID: PMC8261018 DOI: 10.1016/j.mbplus.2021.100076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/18/2021] [Accepted: 06/18/2021] [Indexed: 10/26/2022] Open
Abstract
Mechanistic aspects of type I procollagen biosynthesis in cells are poorly understood. To provide more insight into this process we designed a system to directly image type I procollagen biogenesis by co-expression of fluorescently labeled full size procollagen α1(I) and one α2(I) polypeptides. High resolution images show that collagen α1(I) and α2(I) polypeptides are produced in coordination in discrete structures on the ER membrane, which we termed the collagenosomes. Collagenosomes are disk shaped bodies, 0.5-1 μM in diameter and 200-400 nm thick, in the core of which folding of procollagen takes place. Collagenosomes are intimately associated with the ER membrane and their formation requires intact translational machinery, suggesting that they are the sites of nascent procollagen biogenesis. Collagenosomes show little co-localization with the COPII transport vesicles, which export type I procollagen from the ER, suggesting that these two structures are distinct. LARP6 is the protein which regulates translation of type I collagen mRNAs. The characteristic organization of collagenosomes depends on binding of LARP6 to collagen mRNAs. Without LARP6 regulation, collagenosomes are poorly organized and the folding of α1(I) and α2(I) polypeptides into procollagen in their cores is diminished. This indicates that formation of collagenosomes is dependent on regulated translation of collagen mRNAs. In live cells the size, number and shape of collagenosomes show little change within several hours, suggesting that they are stable structures of type I procollagen biogenesis. This is the first report of structural organization of type I collagen biogenesis in collagenosomes, while the fluorescent reporter system based on simultaneous imaging of both type I collagen polypeptides will enable the detailed elucidation of their structure and function.
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Affiliation(s)
- Branko Stefanovic
- Department of Biomedical Sciences and Translational Science Laboratory, College of Medicine, Florida State University, 1115 West Call Street, Tallahassee, FL 32306, USA
| | - Lela Stefanovic
- Department of Biomedical Sciences and Translational Science Laboratory, College of Medicine, Florida State University, 1115 West Call Street, Tallahassee, FL 32306, USA
| | - Zarko Manojlovic
- Keck School of Medicine of University of Southern California, 1450 Biggy Street, NRT 4510, Los Angeles, CA 90033, USA
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12
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Stefanovic B, Michaels HA, Nefzi A. Discovery of a Lead Compound for Specific Inhibition of Type I Collagen Production in Fibrosis. ACS Med Chem Lett 2021; 12:477-484. [PMID: 33738075 DOI: 10.1021/acsmedchemlett.1c00006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 02/23/2021] [Indexed: 02/06/2023] Open
Abstract
Fibrosis is a major medical problem caused by excessive synthesis of the extracellular matrix, composed predominantly of type I collagen, in various tissues. There are no approved antifibrotic drugs, and the major obstacle in finding clinically relevant compounds is the lack of specificity of current experimental drugs for type I collagen. Here we describe the discovery of a lead compound that specifically inhibited secretion of type I collagen by fibroblasts in culture at IC50 = 4.5 μM. The inhibition was specific for type I collagen, because secretion of fibronectin was not affected. In vitro, the compound inhibited binding of LARP6, the master regulator of translation of type I collagen mRNAs, to the 5' stem-loop sequence element which regulates their translation. Because binding of LARP6 to collagen mRNAs is crucial for the development of fibrosis, this inhibitor represents a promising lead for optimization into specific antifibrotic drugs.
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Affiliation(s)
- Branko Stefanovic
- Florida State University, 1115 West Call Street, Tallahassee, Florida 32306, United States
| | | | - Adel Nefzi
- Florida International University, Port Saint Lucie, Florida 34987, United States
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13
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Al-Ashtal HA, Rubottom CM, Leeper TC, Berman AJ. The LARP1 La-Module recognizes both ends of TOP mRNAs. RNA Biol 2021; 18:248-258. [PMID: 31601159 PMCID: PMC7927982 DOI: 10.1080/15476286.2019.1669404] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/22/2019] [Accepted: 09/12/2019] [Indexed: 12/11/2022] Open
Abstract
La-Related Protein 1 (LARP1) is an RNA-binding protein that regulates the stability and translation of mRNAs encoding the translation machinery, including ribosomal proteins and translation factors. These mRNAs are characterized by a 5'-terminal oligopyrimidine (TOP) motif that coordinates their temporal and stoichiometric expression. While LARP1 represses TOP mRNA translation via the C-terminal DM15 region, the role of the N-terminal La-Module in the recognition and translational regulation of TOP mRNAs remains elusive. Herein we show that the LARP1 La-Module also binds TOP motifs, although in a cap-independent manner. We also demonstrate that it recognizes poly(A) RNA. Further, our data reveal that the LARP1 La-Module can simultaneously engage TOP motifs and poly(A) RNA. These results evoke an intriguing molecular mechanism whereby LARP1 could regulate translation and stabilization of TOP transcripts.
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Affiliation(s)
- Hiba A. Al-Ashtal
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Courtney M. Rubottom
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Thomas C. Leeper
- Department of Chemistry & Biochemistry, Kennesaw State University, Kennesaw, GA, USA
| | - Andrea J. Berman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
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14
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Hau HTA, Ogundele O, Hibbert AH, Monfries CAL, Exelby K, Wood NJ, Nevarez-Mejia J, Carbajal MA, Fleck RA, Dermit M, Mardakheh FK, Williams-Ward VC, Pipalia TG, Conte MR, Hughes SM. Maternal Larp6 controls oocyte development, chorion formation and elevation. Development 2020; 147:dev187385. [PMID: 32054660 PMCID: PMC7055395 DOI: 10.1242/dev.187385] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 01/23/2020] [Indexed: 12/19/2022]
Abstract
La-related protein 6 (Larp6) is a conserved RNA-binding protein found across eukaryotes that has been suggested to regulate collagen biogenesis, muscle development, ciliogenesis, and various aspects of cell proliferation and migration. Zebrafish have two Larp6 family genes: larp6a and larp6b Viable and fertile single and double homozygous larp6a and larp6b zygotic mutants revealed no defects in muscle structure, and were indistinguishable from heterozygous or wild-type siblings. However, larp6a mutant females produced eggs with chorions that failed to elevate fully and were fragile. Eggs from larp6b single mutant females showed minor chorion defects, but chorions from eggs laid by larp6a;larp6b double mutant females were more defective than those from larp6a single mutants. Electron microscopy revealed defective chorionogenesis during oocyte development. Despite this, maternal zygotic single and double mutants were viable and fertile. Mass spectrometry analysis provided a description of chorion protein composition and revealed significant reductions in a subset of zona pellucida and lectin-type proteins between wild-type and mutant chorions that paralleled the severity of the phenotype. We conclude that Larp6 proteins are required for normal oocyte development, chorion formation and egg activation.
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Affiliation(s)
- Hoi Ting A Hau
- Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Oluwaseun Ogundele
- Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Andrew H Hibbert
- Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Clinton A L Monfries
- Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Katherine Exelby
- Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Natalie J Wood
- Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Jessica Nevarez-Mejia
- Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
| | | | - Roland A Fleck
- Centre for Ultrastructural Imaging, King's College London, London SE1 1UL, UK
| | - Maria Dermit
- Barts Cancer Institute, Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London EC1M 6BQ, UK
| | - Faraz K Mardakheh
- Barts Cancer Institute, Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London EC1M 6BQ, UK
| | - Victoria C Williams-Ward
- Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Tapan G Pipalia
- Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Maria R Conte
- Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Simon M Hughes
- Randall Centre for Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL, UK
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15
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Circadian control of the secretory pathway maintains collagen homeostasis. Nat Cell Biol 2020; 22:74-86. [DOI: 10.1038/s41556-019-0441-z] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 11/22/2019] [Indexed: 12/30/2022]
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16
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Slocum E, Craig A, Villanueva A, Germain D. Parity predisposes breasts to the oncogenic action of PAPP-A and activation of the collagen receptor DDR2. Breast Cancer Res 2019; 21:56. [PMID: 31046834 PMCID: PMC6498606 DOI: 10.1186/s13058-019-1142-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 04/16/2019] [Indexed: 12/11/2022] Open
Abstract
Background Women who had children at a young age (less than 25) show a reduced overall risk of breast cancer. However, epidemiological studies showed that for all other women, pregnancy increases the risk of breast cancer and the risk remains higher for decades. Further, even in women who had children at a young age, there is a transient increase risk that peaks 6 years after pregnancy. Women diagnosed with breast cancer following pregnancy show a higher rate of metastasis. Yet, the factors that increase the predisposition of post-partum breasts to more aggressive cancers remain unknown. Pregnancy-associated plasma protein A (PAPP-A) is a secreted protease that is overexpressed in more than 70% of breast cancers. However, PAPP-A is a collagen-dependent oncogene. We initiated this study to test the effect of PAPP-A on the predisposition of post-partum breasts. Methods We used PAPP-A mouse models for the analysis of its effect on virgin, involuting, or post-partum mammary glands. We performed second-harmonic generation microscopy for the analysis of collagen, defined tumor-associated collagen signature (TACS), the rate of mammary tumors, and the status of the collagen-DDR2-Snail axis of metastasis. We knockdown DDR2 by CRISPR and performed invasion assays. A transcriptomic approach was used to define a PAPP-A and parity-dependent genetic signature and assess its correlation with breast cancer recurrence in humans. Results We confirmed that post-partum mammary glands have a higher level of collagen than virgin glands and that this collagen is characterized by an anti-proliferative architecture. However, PAPP-A converts the anti-proliferative post-partum collagen into pro-tumorigenic collagen. We show that PAPP-A activates the collagen receptor DDR2 and metastasis. Further, deletion of DDR2 by CRISPR abolished the effect of PAPP-A on invasion. We defined a PAPP-A-driven genetic signature that identifies patients at higher risk of metastasis. Conclusions These results support the notion that information about pregnancy may be critical in the prognosis of breast cancer as passage through a single pregnancy predisposes to the oncogenic action of PAPP-A. Our data indicate that history of pregnancy combined with the expression of PAPP-A-driven genetic signature may be useful to identify patients at higher risk of metastatic disease. Electronic supplementary material The online version of this article (10.1186/s13058-019-1142-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elizabeth Slocum
- Department of Medicine, Division of Hematology/Oncology, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Amanda Craig
- Department of Medicine, Division of Liver Diseases, Liver Cancer Program, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Augusto Villanueva
- Department of Medicine, Division of Liver Diseases, Liver Cancer Program, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Doris Germain
- Department of Medicine, Division of Hematology/Oncology, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA. .,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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17
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Stefanovic L, Stefanovic B. Technology for Discovery of Antifibrotic Drugs: Phenotypic Screening for LARP6 Inhibitors Using Inverted Yeast Three Hybrid System. Assay Drug Dev Technol 2019; 17:116-127. [PMID: 30901265 DOI: 10.1089/adt.2018.904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Fibrosis is defined by excessive production of type I collagen in various organs. Excessive type I collagen production in fibrosis is stimulated by binding of RNA protein LARP6 to the structural element of collagen mRNAs, the 5' stem loop (5'SL). The LARP6-dependent regulation is specific for type I collagen and critical for fibrosis development. Inhibitors of LARP6 binding have potential to be specific antifibrotic drugs, as evidenced by the discovery of one such inhibitor. To create technology for phenotypic screening of additional compounds we developed an inverted yeast three hybrid system. The system is based on expression of human LARP6 and a short RNA containing the 5'SL of human collagen α1(I) mRNA in Saccharomyces cerevisiae cells. The cells were engineered in such a way that when LARP6 is bound to 5'SL RNA they fail to grow in a specific synthetic medium. Dissociation of LARP6 from 5'SL RNA permits the cell growth, allowing identification of the inhibitors of LARP6 binding. The assay simply involves measuring optical density of cells growing in multiwall plates and is pertinent for high throughput applications. We describe the specificity of the system and its characteristics for high throughput screening. As a proof of principle, the result of one screen using collection of FDA approved drugs is also presented. This screen demonstrates that using this technology discovery of novel LARP6 inhibitors is possible.
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Affiliation(s)
- Lela Stefanovic
- 1 Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida
| | - Branko Stefanovic
- 1 Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida
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18
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Stefanovic B, Manojlovic Z, Vied C, Badger CD, Stefanovic L. Discovery and evaluation of inhibitor of LARP6 as specific antifibrotic compound. Sci Rep 2019; 9:326. [PMID: 30674965 PMCID: PMC6344531 DOI: 10.1038/s41598-018-36841-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 11/27/2018] [Indexed: 01/17/2023] Open
Abstract
Fibrosis is characterized by excessive production of type I collagen. Biosynthesis of type I collagen in fibrosis is augmented by binding of protein LARP6 to the 5' stem-loop structure (5'SL), which is found exclusively in type I collagen mRNAs. A high throughput screen was performed to discover inhibitors of LARP6 binding to 5'SL, as potential antifibrotic drugs. The screen yielded one compound (C9) which was able to dissociate LARP6 from 5' SL RNA in vitro and to inactivate the binding of endogenous LARP6 in cells. Treatment of hepatic stellate cells (liver cells responsible for fibrosis) with nM concentrations of C9 reduced secretion of type I collagen. In precision cut liver slices, as an ex vivo model of hepatic fibrosis, C9 attenuated the profibrotic response at 1 μM. In prophylactic and therapeutic animal models of hepatic fibrosis C9 prevented development of fibrosis or hindered the progression of ongoing fibrosis when administered at 1 mg/kg. Toxicogenetics analysis revealed that only 42 liver genes changed expression after administration of C9 for 4 weeks, suggesting minimal off target effects. Based on these results, C9 represents the first LARP6 inhibitor with significant antifibrotic activity.
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Affiliation(s)
- Branko Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, 1115 West Call Street, Tallahassee, FL, 32306, USA.
| | - Zarko Manojlovic
- Keck School of Medicine of University of Southern California, 1450 Biggy Street, NRT 4510, Los Angeles, CA, 90033, USA
| | - Cynthia Vied
- Translational Science Laboratory, College of Medicine, Florida State University, 1115 West Call Street, Tallahassee, FL, 32306, USA
| | - Crystal-Dawn Badger
- Translational Science Laboratory, College of Medicine, Florida State University, 1115 West Call Street, Tallahassee, FL, 32306, USA
- Proteomics and Metabolomics Facility, Colorado State University, 401 West Pitkin Street, Fort Collins, CO, 80521, USA
| | - Lela Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, 1115 West Call Street, Tallahassee, FL, 32306, USA
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19
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20
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Schildgen V, Pieper M, Khalfaoui S, Arnold WH, Schildgen O. Human Bocavirus Infection of Permanent Cells Differentiated to Air-Liquid Interface Cultures Activates Transcription of Pathways Involved in Tumorigenesis. Cancers (Basel) 2018; 10:cancers10110410. [PMID: 30380741 PMCID: PMC6267225 DOI: 10.3390/cancers10110410] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/12/2018] [Accepted: 10/26/2018] [Indexed: 02/07/2023] Open
Abstract
The parvoviral human bocavirus (HBoV) is a respiratory pathogen, able to persist in infected cells. The viral DNA has been identified in colorectal and lung tumors and thus it was postulated that the virus could be associated with tumorigenesis. This assumption was supported by the fact that in HBoV-infected patients and in an in vitro cell culture system, pro-cancerogenic and -fibrotic cytokines were expressed. In this work, it is shown by a whole transcriptome analysis that, also at the mRNA level, several pathways leading to neoplasia and tumorigenesis are significantly upregulated. In total, a set of 54 transcripts are specifically regulated by HBoV, of which the majority affects canonical pathways that may lead to tumor development if they become deregulated. Moreover, pathways leading to necrosis, apoptosis and cell death are downregulated, supporting the hypothesis that HBoV might contribute to the development of some kinds of cancer.
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Affiliation(s)
- Verena Schildgen
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Kliniken der Privaten Universität Witten/Herdecke mit Sitz in Köln, Ostmerheimer Str. 200, D-51109 Köln/Cologne, Germany.
| | - Monika Pieper
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Kliniken der Privaten Universität Witten/Herdecke mit Sitz in Köln, Ostmerheimer Str. 200, D-51109 Köln/Cologne, Germany.
| | - Soumaya Khalfaoui
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Kliniken der Privaten Universität Witten/Herdecke mit Sitz in Köln, Ostmerheimer Str. 200, D-51109 Köln/Cologne, Germany.
| | - Wolfgang H Arnold
- Universität Witten/Herdecke, Lehrstuhl für Biologische und Materialkundliche Grundlagen der Zahnmedizin, D-58448 Witten, Germany.
| | - Oliver Schildgen
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Kliniken der Privaten Universität Witten/Herdecke mit Sitz in Köln, Ostmerheimer Str. 200, D-51109 Köln/Cologne, Germany.
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21
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Weng L, Jia S, Xu C, Ye J, Cao Y, Liu Y, Zheng M. Nogo-C regulates post myocardial infarction fibrosis through the interaction with ER Ca 2+ leakage channel Sec61α in mouse hearts. Cell Death Dis 2018; 9:612. [PMID: 29795235 PMCID: PMC5966439 DOI: 10.1038/s41419-018-0598-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/10/2018] [Accepted: 04/13/2018] [Indexed: 12/13/2022]
Abstract
Cardiac fibrosis is an independent risk factor for heart failure and even the leading cause of death in myocardial infarction patients. However, molecular mechanisms associated with the pathogenesis of cardiac fibrosis following myocardial infarction are not yet fully understood. Nogo-C protein ubiquitously expresses in tissues including in the heart. Our previous study found that Nogo-C regulated cardiomyocyte apoptosis during myocardial infarction. In the present study, we found that Nogo-C was upregulated in fibrotic hearts after myocardial infarction and in Ang II- or TGF-β1-stimulated cardiac fibroblasts. Overexpression of Nogo-C in cardiac fibroblasts increased expression of pro-fibrogenic proteins, while knockdown of Nogo-C inhibited the fibrotic responses of cardiac fibroblasts to Ang II- or TGF-β1 stimulation. Functionally, Nogo-C deficiency suppressed pro-fibrogenic proteins in post-myocardial infarction hearts and ameliorated post-myocardial infarction cardiac function. Mechanistically, we found that Nogo-C increased intracellular Ca2+ concentration and buffering Ca2+ totally abolished Nogo-C-induced fibrotic responses. Moreover, overexpression of Nogo-C caused increased Sec61α, the Ca2+ leakage channel on endoplasmic reticulum membrane. Nogo-C interacted with Sec61α on endoplasmic reticulum and stabilized Sec61α protein by inhibiting its ubiquitination. Inhibition or knockdown of Sec61α blocked Nogo-C-induced increase of cytosolic Ca2+ concentration and inhibited Nogo-C- and TGF-β1-induced fibrotic responses in cardiac fibroblasts, suggesting that Nogo-C regulates cardiac fibrosis through interacting with Sec61α to mediate the Ca2+ leakage from endoplasmic reticulum. Thus, our results reveal a novel mechanism underlying cardiac fibrosis following myocardial infarction, and provide a therapeutic strategy for cardiac remodeling related heart diseases.
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Affiliation(s)
- Lin Weng
- Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Shi Jia
- Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Chunling Xu
- Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Jingjing Ye
- Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Yangpo Cao
- Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Yingying Liu
- Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Ming Zheng
- Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China.
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22
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Maraia RJ, Mattijssen S, Cruz-Gallardo I, Conte MR. The La and related RNA-binding proteins (LARPs): structures, functions, and evolving perspectives. WILEY INTERDISCIPLINARY REVIEWS. RNA 2017; 8:10.1002/wrna.1430. [PMID: 28782243 PMCID: PMC5647580 DOI: 10.1002/wrna.1430] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/12/2017] [Accepted: 05/15/2017] [Indexed: 01/02/2023]
Abstract
La was first identified as a polypeptide component of ribonucleic protein complexes targeted by antibodies in autoimmune patients and is now known to be a eukaryote cell-ubiquitous protein. Structure and function studies have shown that La binds to a common terminal motif, UUU-3'-OH, of nascent RNA polymerase III (RNAP III) transcripts and protects them from exonucleolytic decay. For precursor-tRNAs, the most diverse and abundant of these transcripts, La also functions as an RNA chaperone that helps to prevent their misfolding. Related to this, we review evidence that suggests that La and its link to RNAP III were significant in the great expansions of the tRNAomes that occurred in eukaryotes. Four families of La-related proteins (LARPs) emerged during eukaryotic evolution with specialized functions. We provide an overview of the high-resolution structural biology of La and LARPs. LARP7 family members most closely resemble La but function with a single RNAP III nuclear transcript, 7SK, or telomerase RNA. A cytoplasmic isoform of La protein as well as LARPs 6, 4, and 1 function in mRNA metabolism and translation in distinct but similar ways, sometimes with the poly(A)-binding protein, and in some cases by direct binding to poly(A)-RNA. New structures of LARP domains, some complexed with RNA, provide novel insights into the functional versatility of these proteins. We also consider LARPs in relation to ancestral La protein and potential retention of links to specific RNA-related pathways. One such link may be tRNA surveillance and codon usage by LARP-associated mRNAs. WIREs RNA 2017, 8:e1430. doi: 10.1002/wrna.1430 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Richard J. Maraia
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
- Commissioned Corps, U.S. Public Health Service, Rockville, MD USA
| | - Sandy Mattijssen
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Isabel Cruz-Gallardo
- Randall Division of Cell and Molecular Biophysics, King's College London, Guy's Campus, London, UK
| | - Maria R. Conte
- Randall Division of Cell and Molecular Biophysics, King's College London, Guy's Campus, London, UK
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Manojlovic Z, Earwood R, Kato A, Perez D, Cabrera OA, Didier R, Megraw TL, Stefanovic B, Kato Y. La-related protein 6 controls ciliated cell differentiation. Cilia 2017; 6:4. [PMID: 28344782 PMCID: PMC5364628 DOI: 10.1186/s13630-017-0047-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 02/16/2017] [Indexed: 01/07/2023] Open
Abstract
Background La-related protein 6 (LARP6) is an evolutionally conserved RNA-binding protein. Vertebrate LARP6 binds the 5′ stem-loop found in mRNAs encoding type I collagen to regulate their translation, but other target mRNAs and additional functions for LARP6 are unknown. The aim of this study was to elucidate an additional function of LARP6 and to evaluate the importance of its function during development. Methods To uncover the role of LARP6 in development, we utilized Morpholino Oligos to deplete LARP6 protein in Xenopus embryos. Then, embryonic phenotypes and ciliary structures of LAPR6 morphants were examined. To identify the molecular mechanism underlying ciliogenesis regulated by LARP6, we tested the expression level of cilia-related genes, which play important roles in ciliogenesis, by RT-PCR or whole mount in situ hybridization (WISH). Results We knocked down LARP6 in Xenopus embryos and found neural tube closure defects. LARP6 mutant, which compromises the collagen synthesis, could rescue these defects. Neural tube closure defects are coincident with lack of cilia, antenna-like cellular organelles with motility- or sensory-related functions, in the neural tube. The absence of cilia at the epidermis was also observed in LARP6 morphants, and this defect was due to the absence of basal bodies which are formed from centrioles and required for ciliary assembly. In the process of multi-ciliated cell (MCC) differentiation, mcidas, which activates the transcription of genes required for centriole formation during ciliogenesis, could partially restore MCCs in LARP6 morphants. In addition, LARP6 likely controls the expression of mcidas in a Notch-independent manner. Conclusions La-related protein 6 is involved in ciliated cell differentiation during development by controlling the expression of cilia-related genes including mcidas. This LARP6 function involves a mechanism that is distinct from its established role in binding to collagen mRNAs and regulating their translation. Electronic supplementary material The online version of this article (doi:10.1186/s13630-017-0047-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zarko Manojlovic
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA.,Department of Translational Genomics, Keck School of Medicine of University of Southern California, Los Angeles, CA 90089-9601 USA
| | - Ryan Earwood
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Akiko Kato
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Diana Perez
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Oscar A Cabrera
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Ruth Didier
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Timothy L Megraw
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Branko Stefanovic
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Yoichi Kato
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
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Abstract
Parameters of bone geometry such as width, length, and cross-sectional area are major determinants of bone strength. Although these traits are highly heritable, few genes influencing bone geometry have been identified. Here, we dissect a major quantitative trait locus (QTL) influencing femur size. This QTL was originally identified in an F2 cross between the C57BL/6J-hg/hg (HG) and CAST/EiJ strains and was referred to as femur length in high growth mice 2 (Feml2). Feml2 was located on chromosome (Chr.) 9 at ∼20 cM. Here, we show that the HG.CAST-(D9Mit249-D9Mit133)/Ucd congenic strain captures Feml2. In an F2 congenic cross, we fine-mapped the location of Feml2 to an ∼6 Mbp region extending from 57.3 to 63.3 Mbp on Chr. 9. We have identified candidates by mining the complete genome sequence of CAST/EiJ and through allele-specific expression (ASE) analysis of growth plates in C57BL/6J × CAST/EiJ F1 hybrids. Interestingly, we also find that the refined location of Feml2 overlaps a cluster of six independent genome-wide associations for human height. This work provides the foundation for the identification of novel genes affecting bone geometry.
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Guo Y, Tang CY, Man XF, Tang HN, Tang J, Zhou CL, Tan SW, Wang M, Feng YZ, Zhou HD. Insulin-like growth factor-1 promotes osteogenic differentiation and collagen I alpha 2 synthesis via induction of mRNA-binding protein LARP6 expression. Dev Growth Differ 2017; 59:94-103. [PMID: 28211947 DOI: 10.1111/dgd.12342] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 01/21/2017] [Accepted: 01/22/2017] [Indexed: 11/30/2022]
Abstract
This study explored the mechanism underlying the stimulation of collagen synthesis and osteoblastic differentiation by insulin-like growth factor 1 (IGF1) in primary mouse osteoblasts. Primary mouse calvarial osteoblasts were cultured and treated with various doses of IGF1 before transfection with siRNA targeting the collagen type I alpha 2 (Col1a2) or La ribonucleoprotein domain family member 6 (Larp6) genes. Alkaline phosphatase (ALP) activity, osteocalcin staining, alizarin red quantification and the expression level of runt-related transcription factor 2 (RUNX2) were performed to assess the differentiation of pre-osteoblasts. Based on Western blot analysis, IGF1 up-regulated COL1A2 protein expression in the primary osteoblasts in a dose- and time-dependent manner. In addition, Col1a2 interference inhibited the differentiation and mineralization of osteoblasts. IGF1 also stimulated the differentiation of mouse primary osteoblasts and increased LARP6 expression during osteogenic differentiation. RNA-Immunoprecipitation (IP) indicated that LARP6 could bind to Col1a2 mRNA after IGF1 stimulation. However, transfection of Larp6-specific siRNA significantly reduced collagen and ALP secretion, mineralization and inhibited the expression of osteocalcin and RUNX2, indicating that Larp6 interference inhibited the differentiation ability of primary mouse calvarial osteoblasts, and these effects could not be reversed by IGF1. Thus, IGF1 could promote COL1A2 expression and osteoblast differentiation in primary mouse calvarial pre-osteoblasts by increasing LARP6 expression via a posttranscriptional mechanism.
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Affiliation(s)
- Yue Guo
- Department of Metabolism & Endocrinology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, ChangSha, Hunan, China
| | - Chen-Yi Tang
- Department of Metabolism & Endocrinology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, ChangSha, Hunan, China
| | - Xiao-Fei Man
- Department of Metabolism & Endocrinology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, ChangSha, Hunan, China
| | - Hao-Neng Tang
- Department of Metabolism & Endocrinology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, ChangSha, Hunan, China
| | - Jun Tang
- Department of Metabolism & Endocrinology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, ChangSha, Hunan, China
| | - Ci-La Zhou
- Department of Metabolism & Endocrinology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, ChangSha, Hunan, China
| | - Shu-Wen Tan
- Department of Metabolism & Endocrinology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, ChangSha, Hunan, China
| | - Min Wang
- Department of Metabolism & Endocrinology, Xiangya Hospital, Central South University, ChangSha, Hunan, China
| | - Yun-Zhi Feng
- Department of Stomatology, The Second Xiangya Hospital, Central South University, ChangSha, Hunan, China
| | - Hou-De Zhou
- Department of Metabolism & Endocrinology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, ChangSha, Hunan, China
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Zhang Y, Stefanovic B. mTORC1 phosphorylates LARP6 to stimulate type I collagen expression. Sci Rep 2017; 7:41173. [PMID: 28112218 PMCID: PMC5255556 DOI: 10.1038/srep41173] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/16/2016] [Indexed: 11/09/2022] Open
Abstract
Excessive deposition of type I collagen causes fibrotic diseases. Binding of La ribonucleoprotein domain family, member 6 (LARP6) to collagen mRNAs regulates their translation and is necessary for high type I collagen expression. Here we show that mTORC1 phosphorylates LARP6 on S348 and S409. The S348A/S409A mutant of LARP6 acts as a dominant negative protein in collagen biosynthesis, which retards secretion of type I collagen and causes excessive posttranslational modifications. Similar effects are seen using mTORC1 inhibitor rapamycin or by knocking down raptor. The S348A/S409A mutant weakly interacts with the accessory protein STRAP, needed for coordinated translation of collagen mRNAs. The interaction of wt LARP6 and STRAP is also attenuated by rapamycin and by raptor knockdown. Additionally, in the absence of S348/S409 phosphorylation LARP6 is sequestered in increasing amounts at the ER membrane. We postulate that phosphorylation of S348/S409 by mTORC1 stimulates the interaction of LARP6 and STRAP to coordinate translation of collagen mRNAs and to release LARP6 from the ER for new round of translation. These mechanisms contribute to high level of collagen expression in fibrosis.
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Affiliation(s)
- Yujie Zhang
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA
| | - Branko Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA
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Zhang Y, Stefanovic B. LARP6 Meets Collagen mRNA: Specific Regulation of Type I Collagen Expression. Int J Mol Sci 2016; 17:419. [PMID: 27011170 PMCID: PMC4813270 DOI: 10.3390/ijms17030419] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/15/2016] [Accepted: 03/17/2016] [Indexed: 01/15/2023] Open
Abstract
Type I collagen is the most abundant structural protein in all vertebrates, but its constitutive rate of synthesis is low due to long half-life of the protein (60-70 days). However, several hundred fold increased production of type I collagen is often seen in reparative or reactive fibrosis. The mechanism which is responsible for this dramatic upregulation is complex, including multiple levels of regulation. However, posttranscriptional regulation evidently plays a predominant role. Posttranscriptional regulation comprises processing, transport, stabilization and translation of mRNAs and is executed by RNA binding proteins. There are about 800 RNA binding proteins, but only one, La ribonucleoprotein domain family member 6 (LARP6), is specifically involved in type I collagen regulation. In the 5'untranslated region (5'UTR) of mRNAs encoding for type I and type III collagens there is an evolutionally conserved stem-loop (SL) structure; this structure is not found in any other mRNA, including any other collagen mRNA. LARP6 binds to the 5'SL in sequence specific manner to regulate stability of collagen mRNAs and their translatability. Here, we will review current understanding of how is LARP6 involved in posttranscriptional regulation of collagen mRNAs. We will also discuss how other proteins recruited by LARP6, including nonmuscle myosin, vimentin, serine threonine kinase receptor associated protein (STRAP), 25 kD FK506 binding protein (FKBP25) and RNA helicase A (RHA), contribute to this process.
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Affiliation(s)
- Yujie Zhang
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA.
| | - Branko Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA.
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Zhang Y, Stefanovic B. Akt mediated phosphorylation of LARP6; critical step in biosynthesis of type I collagen. Sci Rep 2016; 6:22597. [PMID: 26932461 PMCID: PMC4773855 DOI: 10.1038/srep22597] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 02/17/2016] [Indexed: 12/31/2022] Open
Abstract
La ribonucleoprotein domain family, member 6 (LARP6) is the RNA binding protein, which regulates translation of collagen mRNAs and synthesis of type I collagen. Posttranslational modifications of LARP6 and how they affect type I collagen synthesis have not been studied. We show that in lung fibroblasts LARP6 is phosphorylated at 8 serines, 6 of which are located within C-terminal domain. Phosphorylation of LARP6 follows a hierarchical order; S451 phosphorylation being a prerequisite for phosphorylations of other serines. Inhibition of PI3K/Akt pathway reduced the phosphorylation of LARP6, but had no effect on the S451A mutant, suggesting that PI3K/Akt pathway targets S451 and we have identified Akt as the responsible kinase. Overexpression of S451A mutant had dominant negative effect on collagen biosynthesis; drastically reduced secretion of collagen and induced hyper-modifications of collagen α2 (I) polypeptides. This indicates that LARP6 phosphorylation at S451 is critical for regulating translation and folding of collagen polypeptides. Akt inhibitor, GSK-2141795, which is in clinical trials for treatment of solid tumors, reduced collagen production by human lung fibroblasts with EC50 of 150 nM. This effect can be explained by inhibition of LARP6 phosphorylation and suggests that Akt inhibitors may be effective in treatment of various forms of fibrosis.
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Affiliation(s)
- Yujie Zhang
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA
| | - Branko Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA
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