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Xu Y, Patterson MT, Dolfi B, Zhu A, Bertola A, Schrank PR, Gallerand A, Kennedy AE, Hillman H, Dinh L, Shekhar S, Tollison S, Bold TD, Ivanov S, Williams JW. Adrenal gland macrophages regulate glucocorticoid production through Trem2 and TGF-β. JCI Insight 2024; 9:e174746. [PMID: 38869957 PMCID: PMC11383592 DOI: 10.1172/jci.insight.174746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 06/07/2024] [Indexed: 06/15/2024] Open
Abstract
Glucocorticoid synthesis by adrenal glands (AGs) is regulated by the hypothalamic-pituitary-adrenal axis to facilitate stress responses when the host is exposed to stimuli. Recent studies implicate macrophages as potential steroidogenic regulators, but the molecular mechanisms by which AG macrophages exert such influence remain unclear. In this study, we investigated the role of AG macrophages in response to cold challenge or atherosclerotic inflammation as physiologic models of acute or chronic stress. Using single-cell RNA sequencing, we observed dynamic AG macrophage polarization toward classical activation and lipid-associated phenotypes following acute or chronic stimulation. Among transcriptional alterations induced in macrophages, triggering receptor expressed on myeloid cells 2 (Trem2) was highlighted because of its upregulation following stress. Conditional deletion of macrophage Trem2 revealed a protective role in stress responses. Mechanistically, Trem2 deletion led to increased AG macrophage death, abolished the TGF-β-producing capacity of AG macrophages, and resulted in enhanced glucocorticoid production. In addition, enhanced glucocorticoid production was replicated by blockade of TGF-β signaling. Together, these observations suggest that AG macrophages restrict steroidogenesis through Trem2 and TGF-β, which opens potential avenues for immunotherapeutic interventions to resolve stress-related disorders.
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Affiliation(s)
- Yingzheng Xu
- Center for Immunology and
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Michael T Patterson
- Center for Immunology and
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Alisha Zhu
- Center for Immunology and
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Patricia R Schrank
- Center for Immunology and
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Ainsley E Kennedy
- Center for Immunology and
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Hannah Hillman
- Center for Immunology and
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Lynn Dinh
- Center for Immunology and
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Sia Shekhar
- Center for Immunology and
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Samuel Tollison
- Center for Immunology and
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Tyler D Bold
- Center for Immunology and
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Jesse W Williams
- Center for Immunology and
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota, USA
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2
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Su CT, See DHW, Huang YJ, Jao TM, Liu SY, Chou CY, Lai CF, Lin WC, Wang CY, Huang JW, Hung KY. LTBP4 Protects Against Renal Fibrosis via Mitochondrial and Vascular Impacts. Circ Res 2023; 133:71-85. [PMID: 37232163 DOI: 10.1161/circresaha.123.322494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 05/04/2023] [Indexed: 05/27/2023]
Abstract
BACKGROUND As a part of natural disease progression, acute kidney injury (AKI) can develop into chronic kidney disease via renal fibrosis and inflammation. LTBP4 (latent transforming growth factor beta binding protein 4) regulates transforming growth factor beta, which plays a role in renal fibrosis pathogenesis. We previously investigated the role of LTBP4 in chronic kidney disease. Here, we examined the role of LTBP4 in AKI. METHODS LTBP4 expression was evaluated in human renal tissues, obtained from healthy individuals and patients with AKI, using immunohistochemistry. LTBP4 was knocked down in both C57BL/6 mice and human renal proximal tubular cell line HK-2. AKI was induced in mice and HK-2 cells using ischemia-reperfusion injury and hypoxia, respectively. Mitochondrial division inhibitor 1, an inhibitor of DRP1 (dynamin-related protein 1), was used to reduce mitochondrial fragmentation. Gene and protein expression were then examined to assess inflammation and fibrosis. The results of bioenergetic studies for mitochondrial function, oxidative stress, and angiogenesis were assessed. RESULTS LTBP4 expression was upregulated in the renal tissues of patients with AKI. Ltbp4-knockdown mice showed increased renal tissue injury and mitochondrial fragmentation after ischemia-reperfusion injury, as well as increased inflammation, oxidative stress, and fibrosis, and decreased angiogenesis. in vitro studies using HK-2 cells revealed similar results. The energy profiles of Ltbp4-deficient mice and LTBP4-deficient HK-2 cells indicated decreased ATP production. LTBP4-deficient HK-2 cells exhibited decreased mitochondrial respiration and glycolysis. Human aortic endothelial cells and human umbilical vein endothelial cells exhibited decreased angiogenesis when treated with LTBP4-knockdown conditioned media. Mitochondrial division inhibitor 1 treatment ameliorated inflammation, oxidative stress, and fibrosis in mice and decreased inflammation and oxidative stress in HK-2 cells. CONCLUSIONS Our study is the first to demonstrate that LTBP4 deficiency increases AKI severity, consequently leading to chronic kidney disease. Potential therapies focusing on LTBP4-associated angiogenesis and LTBP4-regulated DRP1-dependent mitochondrial division are relevant to renal injury.
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Affiliation(s)
- Chi-Ting Su
- Department of Medicine, National Taiwan University Cancer Center Hospital, Taipei (C.-T.S., D.H.W.S., Y.-J.H.)
- National Taiwan University College of Medicine, Taipei (C.-T.S., D.H.W.S., C.-Y.C., C.-F.L., W.-C.L., C.-Y.W., J.-W.H., K.-Y.H.)
| | - Daniel H W See
- Department of Medicine, National Taiwan University Cancer Center Hospital, Taipei (C.-T.S., D.H.W.S., Y.-J.H.)
- National Taiwan University College of Medicine, Taipei (C.-T.S., D.H.W.S., C.-Y.C., C.-F.L., W.-C.L., C.-Y.W., J.-W.H., K.-Y.H.)
| | - Yue-Jhu Huang
- Department of Medicine, National Taiwan University Cancer Center Hospital, Taipei (C.-T.S., D.H.W.S., Y.-J.H.)
| | - Tzu-Ming Jao
- Global Innovation Joint-Degree Program International Joint Degree Master's Program in Agro-Biomedical Science in Food and Health, College of Medicine, National Taiwan University, Taipei (T.-M.J.)
| | - Shin-Yun Liu
- Liver Disease Prevention and Treatment Research Foundation, Taipei, Taiwan (S.-Y.L.)
| | - Chih-Yi Chou
- National Taiwan University College of Medicine, Taipei (C.-T.S., D.H.W.S., C.-Y.C., C.-F.L., W.-C.L., C.-Y.W., J.-W.H., K.-Y.H.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, National Taiwan University Hospital, National Taiwan University, Taipei (C.-Y.W.)
| | - Chun-Fu Lai
- National Taiwan University College of Medicine, Taipei (C.-T.S., D.H.W.S., C.-Y.C., C.-F.L., W.-C.L., C.-Y.W., J.-W.H., K.-Y.H.)
- Renal Division, Department of Internal Medicine (C.-F.L.), National Taiwan University Hospital, Taipei
| | - Wei-Chou Lin
- Department of Pathology (W.-C.L.), National Taiwan University Hospital, Taipei
| | - Chih-Yuan Wang
- National Taiwan University College of Medicine, Taipei (C.-T.S., D.H.W.S., C.-Y.C., C.-F.L., W.-C.L., C.-Y.W., J.-W.H., K.-Y.H.)
| | - Jenq-Wen Huang
- National Taiwan University College of Medicine, Taipei (C.-T.S., D.H.W.S., C.-Y.C., C.-F.L., W.-C.L., C.-Y.W., J.-W.H., K.-Y.H.)
- Renal Division, Department of Internal Medicine, National Taiwan University Yunlin Branch, Douliu (J.-W.H.)
| | - Kuan-Yu Hung
- National Taiwan University College of Medicine, Taipei (C.-T.S., D.H.W.S., C.-Y.C., C.-F.L., W.-C.L., C.-Y.W., J.-W.H., K.-Y.H.)
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3
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Zhang X, Alanazi YF, Jowitt TA, Roseman AM, Baldock C. Elastic Fibre Proteins in Elastogenesis and Wound Healing. Int J Mol Sci 2022; 23:4087. [PMID: 35456902 PMCID: PMC9027394 DOI: 10.3390/ijms23084087] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/31/2022] [Accepted: 04/03/2022] [Indexed: 12/30/2022] Open
Abstract
As essential components of our connective tissues, elastic fibres give tissues such as major blood vessels, skin and the lungs their elasticity. Their formation is complex and co-ordinately regulated by multiple factors. In this review, we describe key players in elastogenesis: fibrillin-1, tropoelastin, latent TGFβ binding protein-4, and fibulin-4 and -5. We summarise their roles in elastogenesis, discuss the effect of their mutations on relevant diseases, and describe their interactions involved in forming the elastic fibre network. Moreover, we look into their roles in wound repair for a better understanding of their potential application in tissue regeneration.
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Affiliation(s)
- Xinyang Zhang
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK; (X.Z.); (T.A.J.)
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK;
| | - Yasmene F. Alanazi
- Department of Biochemistry, Faculty of Science, University of Tabuk, Tabuk 71491, Saudi Arabia;
| | - Thomas A. Jowitt
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK; (X.Z.); (T.A.J.)
| | - Alan M. Roseman
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK;
| | - Clair Baldock
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK; (X.Z.); (T.A.J.)
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PT, UK;
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4
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Rifkin D, Sachan N, Singh K, Sauber E, Tellides G, Ramirez F. The role of LTBPs in TGF beta signaling. Dev Dyn 2022; 251:95-104. [PMID: 33742701 DOI: 10.1002/dvdy.331] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/25/2021] [Accepted: 03/13/2021] [Indexed: 01/20/2023] Open
Abstract
The purpose of this review is to discuss the transforming growth factor beta (TGFB) binding proteins (LTBP) with respect to their participation in the activity of TGFB. We first describe pertinent aspects of the biology and cell function of the LTBPs. We then summarize the physiological consequences of LTBP loss in humans and mice. Finally, we consider a number of outstanding questions relating to LTBP function.
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Affiliation(s)
- Daniel Rifkin
- Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, USA
| | - Nalani Sachan
- Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, USA
| | - Karan Singh
- Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, USA
| | - Elyse Sauber
- Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, USA
| | - George Tellides
- Department of Surgery, Yale School of Medicine, New Haven, Connecticut, USA
| | - Francesco Ramirez
- Department of Pharmacological Sciences, Icahn School of Medicine at Mt Sinai, New York, New York, USA
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5
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Alanazi YF, Lockhart-Cairns MP, Cain SA, Jowitt TA, Weiss AS, Baldock C. Autosomal Recessive Cutis Laxa 1C Mutations Disrupt the Structure and Interactions of Latent TGFβ Binding Protein-4. Front Genet 2021; 12:706662. [PMID: 34539739 PMCID: PMC8446450 DOI: 10.3389/fgene.2021.706662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/23/2021] [Indexed: 11/29/2022] Open
Abstract
Latent TGFβ binding protein-4 (LTBP4) is a multi-domain glycoprotein, essential for regulating the extracellular bioavailability of TGFβ and assembly of elastic fibre proteins, fibrillin-1 and tropoelastin. LTBP4 mutations are linked to autosomal recessive cutis laxa type 1C (ARCL1C), a rare congenital disease characterised by high mortality and severely disrupted connective tissues. Despite the importance of LTBP4, the structure and molecular consequences of disease mutations are unknown. Therefore, we analysed the structural and functional consequences of three ARCL1C causing point mutations which effect highly conserved cysteine residues. Our structural and biophysical data show that the LTBP4 N- and C-terminal regions are monomeric in solution and adopt extended conformations with the mutations resulting in subtle changes to their conformation. Similar to LTBP1, the N-terminal region is relatively inflexible, whereas the C-terminal region is flexible. Interaction studies show that one C-terminal mutation slightly decreases binding to fibrillin-1. We also found that the LTBP4 C-terminal region directly interacts with tropoelastin which is perturbed by both C-terminal ARCL1C mutations, whereas an N-terminal mutation increased binding to fibulin-4 but did not affect the interaction with heparan sulphate. Our results suggest that LTBP4 mutations contribute to ARCL1C by disrupting the structure and interactions of LTBP4 which are essential for elastogenesis in a range of mammalian connective tissues.
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Affiliation(s)
- Yasmene F Alanazi
- Wellcome Trust Centre for Cell Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Science, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Michael P Lockhart-Cairns
- Wellcome Trust Centre for Cell Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Science, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Stuart A Cain
- Wellcome Trust Centre for Cell Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Science, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Thomas A Jowitt
- Wellcome Trust Centre for Cell Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Science, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Anthony S Weiss
- Charles Perkins Centre, University of Sydney, Darlington, NSW, Australia.,School of Life and Environmental Sciences, Darlington, NSW, Australia.,Sydney Nano Institute, The University of Sydney, Darlington, NSW, Australia
| | - Clair Baldock
- Wellcome Trust Centre for Cell Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Science, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
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6
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Voulgaris TA, Karamanolis GP. Esophageal manifestation in patients with scleroderma. World J Clin Cases 2021; 9:5408-5419. [PMID: 34307594 PMCID: PMC8281422 DOI: 10.12998/wjcc.v9.i20.5408] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 04/22/2021] [Accepted: 05/10/2021] [Indexed: 02/06/2023] Open
Abstract
The esophagus is the most commonly affected part of the gastrointestinal system in patients with systemic sclerosis (SSc). Esophageal involvement may lead to a significant reduction in patient quality of life. The exact pathophysiology is complex and not yet fully elucidated. Ultimately, esophageal smooth muscle becomes atrophied and replaced by fibrous tissue leading to severe motility disturbance of the distal esophagus. Symptoms are mainly attributed to gastroesophageal reflux disease and to esophageal dysmotility. Compelling evidence has correlated esophageal involvement to the severity of pulmonary disease. No formed guidelines exist about the diagnostic modalities used to assess esophageal disease in patients with SSc, though upper gastrointestinal endoscopy is the first and most important modality used as it can reveal alterations commonly observed in patients with SSc. Further exploration can be made by high resolution manometry and pH-impedance study. Proton pump inhibitors remain the mainstay of treatment, while prokinetic agents are commonly used as add-on therapy in patients with symptoms attributed to gastroesophageal reflux disease not responding to standard therapy as well as to motility disturbances. Gastroesophageal reflux disease symptoms in patients with SSc are frequently difficult to manage, and new therapeutic modalities are emerging. The role of surgical treatment is restricted and should only be preserved for resistant cases.
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Affiliation(s)
- Theodoros A Voulgaris
- Department of Gastroenterology and Hepatology, Laiko General Hospital, National and Kapodistian University of Athens, Athens 11527, Greece
| | - Georgios P Karamanolis
- Department of Gastroenterology and Hepatology, Laiko General Hospital, National and Kapodistian University of Athens, Athens 11527, Greece
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7
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Su CT, Urban Z. LTBP4 in Health and Disease. Genes (Basel) 2021; 12:genes12060795. [PMID: 34071145 PMCID: PMC8224675 DOI: 10.3390/genes12060795] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/14/2021] [Accepted: 05/21/2021] [Indexed: 12/20/2022] Open
Abstract
Latent transforming growth factor β (TGFβ)-binding protein (LTBP) 4, a member of the LTBP family, shows structural homology with fibrillins. Both these protein types are characterized by calcium-binding epidermal growth factor-like repeats interspersed with 8-cysteine domains. Based on its domain composition and distribution, LTBP4 is thought to adopt an extended structure, facilitating the linear deposition of tropoelastin onto microfibrils. In humans, mutations in LTBP4 result in autosomal recessive cutis laxa type 1C, characterized by redundant skin, pulmonary emphysema, and valvular heart disease. LTBP4 is an essential regulator of TGFβ signaling and is related to development, immunity, injury repair, and diseases, playing a central role in regulating inflammation, fibrosis, and cancer progression. In this review, we focus on medical disorders or diseases that may be manipulated by LTBP4 in order to enhance the understanding of this protein.
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Affiliation(s)
- Chi-Ting Su
- Department of Internal Medicine, Renal Division, National Taiwan University Hospital Yunlin Branch, Douliu 640, Taiwan;
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Department of Medicine, National Taiwan University Cancer Center Hospital, Taipei 106, Taiwan
| | - Zsolt Urban
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Correspondence: ; Tel.: +1-412-648-8269
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8
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Krakhotkin DV, Chernylovskyi VA, Mottrie A, Greco F, Bugaev RA. New insights into the pathogenesis of Peyronie's disease: A narrative review. Chronic Dis Transl Med 2020; 6:165-181. [PMID: 32885153 PMCID: PMC7451633 DOI: 10.1016/j.cdtm.2020.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Indexed: 12/11/2022] Open
Abstract
Peyronie's disease (PD) is a benign, progressive fibrotic disorder characterized by scar or plaques within the tunica albuginea (TA) of the penis. This study provides new insights into the pathogenesis of PD based on data from different studies regarding the roles of cytokines, cell signaling pathways, biochemical mechanisms, genetic factors responsible for fibrogenesis. A growing body of literature has shown that PD is a chronically impaired, localized, wound healing process within the TA and the Smith space. It is caused by the influence of different pathological stimuli, most often the effects of mechanical stress during sexual intercourse in genetically sensitive individuals with unusual anatomical TA features, imbalanced matrix metalloproteinase/tissue inhibitor of metalloproteinase (MMP/TIMP), and suppressed antioxidant systems during chronic inflammation. Other intracellular signal cascades are activated during fibrosis along with low expression levels of their negative regulators and transforming growth factor-β1 signaling. The development of multikinase agents with minimal side effects that can block several signal cell pathways would significantly improve fibrosis in PD tissues by acting on common downstream mediators.
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Affiliation(s)
- Denis V Krakhotkin
- Outpatient Department, Central District Hospital, Kamenolomni, Rostov Region, Russia
| | | | - Alexandre Mottrie
- Department of Urology, Onze Lieve Vrouw Hospital, Aalst, Belgium.,ORSI Academy, Melle, Belgium
| | | | - Ruslan A Bugaev
- Outpatient Department, Central District Hospital, Kamenolomni, Rostov Region, Russia
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9
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Gupta N, Langeh N, Sridharan A, Kabra M. Identification of a Novel 19-bp Deletion Mutation in LTBP4 Using Exome Sequencing in Two Siblings with Autosomal Recessive Cutis Laxa Type 1C. J Pediatr Genet 2020; 9:125-131. [PMID: 32341818 DOI: 10.1055/s-0039-1698806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 09/08/2019] [Indexed: 10/25/2022]
Abstract
Autosomal recessive type I cutis laxa is genetically heterogeneous. Biallelic mutations in latent transforming growth factor β-binding protein 4 (LTBP4; MIM*604710) lead to type 1C cutis laxa due to nonsense, frameshift, single base pair indels, or duplication mutations. In this report, we describe the first Indian family with cutis laxa as a result of a novel 19 base pair homozygous deletion leading to premature termination of short isoform LTBP-4S.
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Affiliation(s)
- Neerja Gupta
- Division of Genetics, Department of Pediatrics, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | - Nitika Langeh
- Division of Genetics, Department of Pediatrics, All India Institute of Medical Sciences (AIIMS), New Delhi, India
| | | | - Madhulika Kabra
- Division of Genetics, Department of Pediatrics, All India Institute of Medical Sciences (AIIMS), New Delhi, India
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10
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Fibulin-4 exerts a dual role in LTBP-4L-mediated matrix assembly and function. Proc Natl Acad Sci U S A 2019; 116:20428-20437. [PMID: 31548410 DOI: 10.1073/pnas.1901048116] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Elastogenesis is a hierarchical process by which cells form functional elastic fibers, providing elasticity and the ability to regulate growth factor bioavailability in tissues, including blood vessels, lung, and skin. This process requires accessory proteins, including fibulin-4 and -5, and latent TGF binding protein (LTBP)-4. Our data demonstrate mechanisms in elastogenesis, focusing on the interaction and functional interdependence between fibulin-4 and LTBP-4L and its impact on matrix deposition and function. We show that LTBP-4L is not secreted in the expected extended structure based on its domain composition, but instead adopts a compact conformation. Interaction with fibulin-4 surprisingly induced a conformational switch from the compact to an elongated LTBP-4L structure. This conversion was only induced by fibulin-4 multimers associated with increased avidity for LTBP-4L; fibulin-4 monomers were inactive. The fibulin-4-induced conformational change caused functional consequences in LTBP-4L in terms of binding to other elastogenic proteins, including fibronectin and fibrillin-1, and of LTBP-4L assembly. A transient exposure of LTBP-4L with fibulin-4 was sufficient to stably induce conformational and functional changes; a stable complex was not required. These data define fibulin-4 as a molecular extracellular chaperone for LTBP-4L. The altered LTBP-4L conformation also promoted elastogenesis, but only in the presence of fibulin-4, which is required to escort tropoelastin onto the extended LTBP-4L molecule. Altogether, this study provides a dual mechanism for fibulin-4 in 1) inducing a stable conformational and functional change in LTBP-4L, and 2) promoting deposition of tropoelastin onto the elongated LTBP-4L.
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11
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Bultmann-Mellin I, Dinger K, Debuschewitz C, Loewe KMA, Melcher Y, Plum MTW, Appel S, Rappl G, Willenborg S, Schauss AC, Jüngst C, Krüger M, Dressler S, Nakamura T, Wempe F, Alejandre Alcázar MA, Sterner-Kock A. Role of LTBP4 in alveolarization, angiogenesis, and fibrosis in lungs. Am J Physiol Lung Cell Mol Physiol 2017; 313:L687-L698. [PMID: 28684544 DOI: 10.1152/ajplung.00031.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 06/22/2017] [Accepted: 06/29/2017] [Indexed: 12/31/2022] Open
Abstract
Deficiency of the extracellular matrix protein latent transforming growth factor-β (TGF-β)-binding protein-4 (LTBP4) results in lack of intact elastic fibers, which leads to disturbed pulmonary development and lack of normal alveolarization in humans and mice. Formation of alveoli and alveolar septation in pulmonary development requires the concerted interaction of extracellular matrix proteins, growth factors such as TGF-β, fibroblasts, and myofibroblasts to promote elastogenesis as well as vascular formation in the alveolar septae. To investigate the role of LTBP4 in this context, lungs of LTBP4-deficient (Ltbp4-/-) mice were analyzed in close detail. We elucidate the role of LTBP4 in pulmonary alveolarization and show that three different, interacting mechanisms might contribute to alveolar septation defects in Ltbp4-/- lungs: 1) absence of an intact elastic fiber network, 2) reduced angiogenesis, and 3) upregulation of TGF-β activity resulting in profibrotic processes in the lung.
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Affiliation(s)
- Insa Bultmann-Mellin
- Center for Experimental Medicine, Medical Faculty, University of Cologne, Cologne, Germany
| | - Katharina Dinger
- Center for Experimental Medicine, Medical Faculty, University of Cologne, Cologne, Germany.,Department of Pediatrics and Adolescent Medicine, Medical Faculty, University of Cologne, Cologne, Germany
| | - Carolin Debuschewitz
- Center for Experimental Medicine, Medical Faculty, University of Cologne, Cologne, Germany
| | - Katharina M A Loewe
- Center for Experimental Medicine, Medical Faculty, University of Cologne, Cologne, Germany
| | - Yvonne Melcher
- Center for Experimental Medicine, Medical Faculty, University of Cologne, Cologne, Germany
| | - Miro T W Plum
- Center for Experimental Medicine, Medical Faculty, University of Cologne, Cologne, Germany
| | - Sarah Appel
- Department of Pediatrics and Adolescent Medicine, Medical Faculty, University of Cologne, Cologne, Germany
| | - Gunter Rappl
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Department I of Internal Medicine, University Hospital Cologne, Cologne, Germany
| | | | - Astrid C Schauss
- Cluster of Excellence, Cellular Stress Response in Aging-Related Diseases, Core Facility Imaging, University of Cologne, Cologne, Germany
| | - Christian Jüngst
- Cluster of Excellence, Cellular Stress Response in Aging-Related Diseases, Core Facility Imaging, University of Cologne, Cologne, Germany
| | - Marcus Krüger
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cluster of Excellence, Cellular Stress Response in Aging-Related Diseases, Core Facility Proteomics, University of Cologne, Cologne, Germany.,Institute for Genetics, University of Cologne, Cologne, Germany
| | - Sven Dressler
- Institute of Medical Immunology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Tomoyuki Nakamura
- Department of Pharmacology, Kansai Medical University, Osaka, Japan; and
| | - Frank Wempe
- Department of Molecular Hematology, University of Frankfurt Medical School, Frankfurt am Main, Germany
| | - Miguel A Alejandre Alcázar
- Department of Pediatrics and Adolescent Medicine, Medical Faculty, University of Cologne, Cologne, Germany
| | - Anja Sterner-Kock
- Center for Experimental Medicine, Medical Faculty, University of Cologne, Cologne, Germany;
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12
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Troilo H, Steer R, Collins RF, Kielty CM, Baldock C. Independent multimerization of Latent TGFβ Binding Protein-1 stabilized by cross-linking and enhanced by heparan sulfate. Sci Rep 2016; 6:34347. [PMID: 27677855 PMCID: PMC5039643 DOI: 10.1038/srep34347] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 09/08/2016] [Indexed: 11/09/2022] Open
Abstract
TGFβ plays key roles in fibrosis and cancer progression, and latency is conferred by covalent linkage to latent TGFβ binding proteins (LTBPs). LTBP1 is essential for TGFβ folding, secretion, matrix localization and activation but little is known about its structure due to its inherent size and flexibility. Here we show that LTBP1 adopts an extended conformation with stable matrix-binding N-terminus, extended central array of 11 calcium-binding EGF domains and flexible TGFβ-binding C-terminus. Moreover we demonstrate that LTBP1 forms short filament-like structures independent of other matrix components. The termini bind to each other to facilitate linear extension of the filament, while the N-terminal region can serve as a branch-point. Multimerization is enhanced in the presence of heparin and stabilized by the matrix cross-linking enzyme transglutaminase-2. These assemblies will extend the span of LTBP1 to potentially allow simultaneous N-terminal matrix and C-terminal fibrillin interactions providing tethering for TGFβ activation by mechanical force.
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Affiliation(s)
- Helen Troilo
- The Wellcome Trust Centre for Cell-Matrix Research is within the School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Ruth Steer
- The Wellcome Trust Centre for Cell-Matrix Research is within the School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Richard F Collins
- The Wellcome Trust Centre for Cell-Matrix Research is within the School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Cay M Kielty
- The Wellcome Trust Centre for Cell-Matrix Research is within the School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Clair Baldock
- The Wellcome Trust Centre for Cell-Matrix Research is within the School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
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13
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Bultmann-Mellin I, Essers J, van Heijingen PM, von Melchner H, Sengle G, Sterner-Kock A. Function of Ltbp-4L and fibulin-4 in survival and elastogenesis in mice. Dis Model Mech 2016; 9:1367-1374. [PMID: 27585882 PMCID: PMC5117228 DOI: 10.1242/dmm.026005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/15/2016] [Indexed: 12/18/2022] Open
Abstract
LTBP-4L and LTBP-4S are two isoforms of the extracellular matrix protein latent-transforming growth factor beta-binding protein 4 (LTBP-4). The mutational inactivation of both isoforms causes autosomal recessive cutis laxa type 1C (ARCL1C) in humans and an ARCL1C-like phenotype in Ltbp4-/- mice, both characterized by high postnatal mortality and severely affected elastogenesis. However, genetic data in mice suggest isoform-specific functions for Ltbp-4 because Ltbp4S-/- mice, solely expressing Ltbp-4L, survive to adulthood. This clearly suggests a requirement of Ltbp-4L for postnatal survival. A major difference between Ltbp4S-/- and Ltbp4-/- mice is the matrix incorporation of fibulin-4 (a key factor for elastogenesis; encoded by the Efemp2 gene), which is normal in Ltbp4S-/- mice, whereas it is defective in Ltbp4-/- mice, suggesting that the presence of Ltbp-4L might be required for this process. To investigate the existence of a functional interaction between Ltbp-4L and fibulin-4, we studied the consequences of fibulin-4 deficiency in mice only expressing Ltbp-4L. Resulting Ltbp4S-/-;Fibulin-4R/R mice showed a dramatically reduced lifespan compared to Ltbp4S-/- or Fibulin-4R/R mice, which survive to adulthood. This dramatic reduction in survival of Ltbp4S-/-;Fibulin-4R/R mice correlates with severely impaired elastogenesis resulting in defective alveolar septation and distal airspace enlargement in lung, and increased aortic wall thickness with severely fragmented elastic lamellae. Additionally, Ltbp4S-/-;Fibulin-4R/R mice suffer from aortic aneurysm formation combined with aortic tortuosity, in contrast to Ltbp4S-/- or Fibulin-4R/R mice. Together, in accordance with our previous biochemical findings of a physical interaction between Ltbp-4L and fibulin-4, these novel in vivo data clearly establish a functional link between Ltbp-4L and fibulin-4 as a crucial molecular requirement for survival and elastogenesis in mice.
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Affiliation(s)
- Insa Bultmann-Mellin
- Center for Experimental Medicine, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Jeroen Essers
- Department of Molecular Genetics, Cancer Genomics Centre, Erasmus MC, 3015 CN Rotterdam, The Netherlands.,Department of Radiation Oncology, Erasmus MC, 3015 CN Rotterdam, The Netherlands.,Department of Vascular Surgery, Erasmus MC, 3015 CN Rotterdam, The Netherlands
| | - Paula M van Heijingen
- Department of Molecular Genetics, Cancer Genomics Centre, Erasmus MC, 3015 CN Rotterdam, The Netherlands
| | - Harald von Melchner
- Department of Molecular Hematology, University of Frankfurt Medical School, 60590 Frankfurt am Main, Germany
| | - Gerhard Sengle
- Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Anja Sterner-Kock
- Center for Experimental Medicine, Medical Faculty, University of Cologne, 50931 Cologne, Germany
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14
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Robertson IB, Rifkin DB. Regulation of the Bioavailability of TGF-β and TGF-β-Related Proteins. Cold Spring Harb Perspect Biol 2016; 8:8/6/a021907. [PMID: 27252363 DOI: 10.1101/cshperspect.a021907] [Citation(s) in RCA: 265] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The bioavailability of members of the transforming growth factor β (TGF-β) family is controlled by a number of mechanisms. Bona fide TGF-β is sequestered into the matrix in a latent state and must be activated before it can bind to its receptors. Here, we review the molecules and mechanisms that regulate the bioavailability of TGF-β and compare these mechanisms with those used to regulate other TGF-β family members. We also assess the physiological significance of various latent TGF-β activators, as well as other extracellular modulators of TGF-β family signaling, by examining the available in vivo data from knockout mouse models and other biological systems.
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Affiliation(s)
- Ian B Robertson
- Departments of Cell Biology, New York University School of Medicine, New York, New York 10016
| | - Daniel B Rifkin
- Departments of Cell Biology, New York University School of Medicine, New York, New York 10016 Departments of Medicine, New York University School of Medicine, New York, New York 10016
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15
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Overexpression of Latent TGFβ Binding Protein 4 in Muscle Ameliorates Muscular Dystrophy through Myostatin and TGFβ. PLoS Genet 2016; 12:e1006019. [PMID: 27148972 PMCID: PMC4858180 DOI: 10.1371/journal.pgen.1006019] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 04/08/2016] [Indexed: 01/06/2023] Open
Abstract
Latent TGFβ binding proteins (LTBPs) regulate the extracellular availability of latent TGFβ. LTBP4 was identified as a genetic modifier of muscular dystrophy in mice and humans. An in-frame insertion polymorphism in the murine Ltbp4 gene associates with partial protection against muscular dystrophy. In humans, nonsynonymous single nucleotide polymorphisms in LTBP4 associate with prolonged ambulation in Duchenne muscular dystrophy. To better understand LTBP4 and its role in modifying muscular dystrophy, we created transgenic mice overexpressing the protective murine allele of LTBP4 specifically in mature myofibers using the human skeletal actin promoter. Overexpression of LTBP4 protein was associated with increased muscle mass and proportionally increased strength compared to age-matched controls. In order to assess the effects of LTBP4 in muscular dystrophy, LTBP4 overexpressing mice were bred to mdx mice, a model of Duchenne muscular dystrophy. In this model, increased LTBP4 led to greater muscle mass with proportionally increased strength, and decreased fibrosis. The increase in muscle mass and reduction in fibrosis were similar to what occurs when myostatin, a related TGFβ family member and negative regulator of muscle mass, was deleted in mdx mice. Supporting this, we found that myostatin forms a complex with LTBP4 and that overexpression of LTBP4 led to a decrease in myostatin levels. LTBP4 also interacted with TGFβ and GDF11, a protein highly related to myostatin. These data identify LTBP4 as a multi-TGFβ family ligand binding protein with the capacity to modify muscle disease through overexpression. Muscular dystrophy is a genetic disease with muscle weakness, replacement of muscle tissue with fibrosis, and premature death. The gene for latent TGFβ binding protein 4 (LTBP4) was previously found to modify muscular dystrophy in both mice and humans with variants that confer protection from disease. In order to better understand this modifier gene, the protective version of LTBP4 was overexpressed specifically in the skeletal muscles of mice. Increased levels of LTBP4 protein resulted in increased muscle mass. Overexpression of LTBP4 in a mouse model of Duchenne muscular dystrophy alleviated many disease-associated features producing larger muscles, increased strength, and reduced fibrosis in muscle. LTBP4 formed a complex with myostatin, a protein that when inhibited leads to muscle growth. In LTBP4-overexpressing mice, active myostatin protein was decreased. This study shows that LTBP4 modifies muscular dystrophy based on its ability to scaffold and regulate multiple TGFβ family members including myostatin.
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16
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Abstract
The LTBPs (or latent transforming growth factor β binding proteins) are important components of the extracellular matrix (ECM) that interact with fibrillin microfibrils and have a number of different roles in microfibril biology. There are four LTBPs isoforms in the human genome (LTBP-1, -2, -3, and -4), all of which appear to associate with fibrillin and the biology of each isoform is reviewed here. The LTBPs were first identified as forming latent complexes with TGFβ by covalently binding the TGFβ propeptide (LAP) via disulfide bonds in the endoplasmic reticulum. LAP in turn is cleaved from the mature TGFβ precursor in the trans-golgi network but LAP and TGFβ remain strongly bound through non-covalent interactions. LAP, TGFβ, and LTBP together form the large latent complex (LLC). LTBPs were originally thought to primarily play a role in maintaining TGFβ latency and targeting the latent growth factor to the extracellular matrix (ECM), but it has also been shown that LTBP-1 participates in TGFβ activation by integrins and may also regulate activation by proteases and other factors. LTBP-3 appears to have a role in skeletal formation including tooth development. As well as having important functions in TGFβ regulation, TGFβ-independent activities have recently been identified for LTBP-2 and LTBP-4 in stabilizing microfibril bundles and regulating elastic fiber assembly.
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17
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Bultmann-Mellin I, Conradi A, Maul AC, Dinger K, Wempe F, Wohl AP, Imhof T, Wunderlich FT, Bunck AC, Nakamura T, Koli K, Bloch W, Ghanem A, Heinz A, von Melchner H, Sengle G, Sterner-Kock A. Modeling autosomal recessive cutis laxa type 1C in mice reveals distinct functions for Ltbp-4 isoforms. Dis Model Mech 2015; 8:403-15. [PMID: 25713297 PMCID: PMC4381339 DOI: 10.1242/dmm.018960] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/16/2015] [Indexed: 01/03/2023] Open
Abstract
Recent studies have revealed an important role for LTBP-4 in elastogenesis. Its mutational inactivation in humans causes autosomal recessive cutis laxa type 1C (ARCL1C), which is a severe disorder caused by defects of the elastic fiber network. Although the human gene involved in ARCL1C has been discovered based on similar elastic fiber abnormalities exhibited by mice lacking the short Ltbp-4 isoform (Ltbp4S(-/-)), the murine phenotype does not replicate ARCL1C. We therefore inactivated both Ltbp-4 isoforms in the mouse germline to model ARCL1C. Comparative analysis of Ltbp4S(-/-) and Ltbp4-null (Ltbp4(-/-)) mice identified Ltbp-4L as an important factor for elastogenesis and postnatal survival, and showed that it has distinct tissue expression patterns and specific molecular functions. We identified fibulin-4 as a previously unknown interaction partner of both Ltbp-4 isoforms and demonstrated that at least Ltbp-4L expression is essential for incorporation of fibulin-4 into the extracellular matrix (ECM). Overall, our results contribute to the current understanding of elastogenesis and provide an animal model of ARCL1C.
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Affiliation(s)
- Insa Bultmann-Mellin
- Center for Experimental Medicine, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Anne Conradi
- Center for Experimental Medicine, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Alexandra C Maul
- Center for Experimental Medicine, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Katharina Dinger
- Center for Experimental Medicine, Medical Faculty, University of Cologne, 50931 Cologne, Germany. Department of Pediatrics and Adolescent Medicine, Medical Faculty, University of Cologne, 50937 Cologne, Germany
| | - Frank Wempe
- Department of Molecular Hematology, University of Frankfurt Medical School, 60590 Frankfurt am Main, Germany
| | - Alexander P Wohl
- Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Thomas Imhof
- Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany. Institute for Dental Research and Oral Musculoskeletal Biology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - F Thomas Wunderlich
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany. Max Planck Institute for Metabolism Research, 50931 Cologne, Germany. Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Alexander C Bunck
- Department of Radiology, Medical Faculty, University of Cologne, 50937 Cologne, Germany
| | - Tomoyuki Nakamura
- Department of Pharmacology, Kansai Medical University, Osaka 570-8506, Japan
| | - Katri Koli
- Research Programs Unit and Transplantation Laboratory, Haartman Institute, University of Helsinki, 00014 Helsinki, Finland
| | - Wilhelm Bloch
- Institute of Cardiology and Sports Medicine, German Sport University Cologne, 50933 Cologne, Germany
| | - Alexander Ghanem
- Department of Medicine/Cardiology, University of Bonn, 53127 Bonn, Germany
| | - Andrea Heinz
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Harald von Melchner
- Department of Molecular Hematology, University of Frankfurt Medical School, 60590 Frankfurt am Main, Germany
| | - Gerhard Sengle
- Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany. Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Anja Sterner-Kock
- Center for Experimental Medicine, Medical Faculty, University of Cologne, 50931 Cologne, Germany.
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18
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Dabovic B, Robertson IB, Zilberberg L, Vassallo M, Davis EC, Rifkin DB. Function of latent TGFβ binding protein 4 and fibulin 5 in elastogenesis and lung development. J Cell Physiol 2015; 230:226-36. [PMID: 24962333 DOI: 10.1002/jcp.24704] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 06/20/2014] [Indexed: 01/20/2023]
Abstract
Mice deficient in Latent TGFβ Binding Protein 4 (Ltbp4) display a defect in lung septation and elastogenesis. The lung septation defect is normalized by genetically decreasing TGFβ2 levels. However, the elastic fiber assembly is not improved in Tgfb2(-/-) ;Ltbp4S(-/-) compared to Ltbp4S(-/-) lungs. We found that decreased levels of TGFβ1 or TGFβ3 did not improve lung septation indicating that the TGFβ isoform elevated in Ltbp4S(-/-) lungs is TGFβ2. Expression of a form of Ltbp4 that could not bind latent TGFβ did not affect lung phenotype indicating that normal lung development does not require the formation of LTBP4-latent TGFβ complexes. Therefore, the change in TGFβ-level in the lungs is not directly related to Ltbp4 deficiency but probably is a consequence of changes in the extracellular matrix. Interestingly, combination of the Ltbp4S(-/-) mutation with a fibulin-5 null mutant in Fbln5(-/-) ;Ltbp4S(-/-) mice improves the lung septation compared to Ltbp4S(-/-) lungs. Large globular elastin aggregates characteristic for Ltbp4S(-/-) lungs do not form in Fbln5(-/-) ;Ltbp4S(-/-) lungs and EM studies showed that elastic fibers in Fbln5(-/-) ;Ltbp4S(-/-) lungs resemble those found in Fbln5(-/-) mice. These results are consistent with a role for TGFβ2 in lung septation and for Ltbp4 in regulating fibulin-5 dependent elastic fiber assembly.
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Affiliation(s)
- Branka Dabovic
- Departments of Cell Biology, New York University Medical Center, 550 First Avenue, New York, NY, USA
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19
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Yang JO, Hwang S, Kim WY, Park SJ, Kim SC, Park K, Lee B. Identification of ethnically specific genetic variations in pan-asian ethnos. Genomics Inform 2014; 12:42-7. [PMID: 24748860 PMCID: PMC3990765 DOI: 10.5808/gi.2014.12.1.42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 11/27/2013] [Accepted: 11/29/2013] [Indexed: 11/24/2022] Open
Abstract
Asian populations contain a variety of ethnic groups that have ethnically specific genetic differences. Ethnic variants may be highly relevant in disease and human differentiation studies. Here, we identified ethnically specific variants and then investigated their distribution across Asian ethnic groups. We obtained 58,960 Pan-Asian single nucleotide polymorphisms of 1,953 individuals from 72 ethnic groups of 11 Asian countries. We selected 9,306 ethnic variant single nucleotide polymorphisms (ESNPs) and 5,167 ethnic variant copy number polymorphisms (ECNPs) using the nearest shrunken centroid method. We analyzed ESNPs and ECNPs in 3 hierarchical levels: superpopulation, subpopulation, and ethnic population. We also identified ESNP- and ECNP-related genes and their features. This study represents the first attempt to identify Asian ESNP and ECNP markers, which can be used to identify genetic differences and predict disease susceptibility and drug effectiveness in Asian ethnic populations.
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Affiliation(s)
- Jin Ok Yang
- Korean BioInformation Center (KOBIC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 305-806, Korea
| | - Sohyun Hwang
- Korean BioInformation Center (KOBIC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 305-806, Korea
| | - Woo-Yeon Kim
- Bioinformatics Team, CSP R&D Center, Samsung SDS, Seoul 135-918, Korea
| | - Seong-Jin Park
- Korean BioInformation Center (KOBIC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 305-806, Korea
| | - Sang Cheol Kim
- Samsung Genome Institute, Samsung Medical Center, Seoul 135-710, Korea
| | - Kiejung Park
- Korean BioInformation Center (KOBIC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 305-806, Korea
| | - Byungwook Lee
- Korean BioInformation Center (KOBIC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 305-806, Korea
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20
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Urban Z, Davis EC. Cutis laxa: intersection of elastic fiber biogenesis, TGFβ signaling, the secretory pathway and metabolism. Matrix Biol 2013; 33:16-22. [PMID: 23954411 DOI: 10.1016/j.matbio.2013.07.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 07/08/2013] [Accepted: 07/09/2013] [Indexed: 12/11/2022]
Abstract
Cutis laxa (CL), a disease characterized by redundant and inelastic skin, displays extensive locus heterogeneity. Together with geroderma osteodysplasticum and arterial tortuosity syndrome, which show phenotypic overlap with CL, eleven CL-related genes have been identified to date, which encode proteins within 3 groups. Elastin, fibulin-4, fibulin-5 and latent transforming growth factor-β-binding protein 4 are secreted proteins which form elastic fibers and are involved in the sequestration and subsequent activation of transforming growth factor-β (TGFβ). Proteins within the second group, localized to the secretory pathway, perform transport and membrane trafficking functions necessary for the modification and secretion of elastic fiber components. Key proteins include a subunit of the vacuolar-type proton pump, which ensures the efficient secretion of tropoelastin, the precursor or elastin. A copper transporter is required for the activity of lysyl oxidases, which crosslink collagen and elastin. A Rab6-interacting goglin recruits kinesin motors to Golgi-vesicles facilitating the transport from the Golgi to the plasma membrane. The Rab and Ras interactor 2 regulates the activity of Rab5, a small guanosine triphosphatase essential for the endocytosis of various cell surface receptors, including integrins. Proteins of the third group related to CL perform metabolic functions within the mitochondria, inhibiting the accumulation of reactive oxygen species. Two of these proteins catalyze subsequent steps in the conversion of glutamate to proline. The third transports dehydroascorbate into mitochondria. Recent studies on CL-related proteins highlight the intricate connections among membrane trafficking, metabolism, extracellular matrix assembly, and TGFβ signaling.
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Affiliation(s)
- Zsolt Urban
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, United States.
| | - Elaine C Davis
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, H3A 0C7 Canada
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21
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Robertson IB, Rifkin DB. Unchaining the beast; insights from structural and evolutionary studies on TGFβ secretion, sequestration, and activation. Cytokine Growth Factor Rev 2013; 24:355-72. [PMID: 23849989 DOI: 10.1016/j.cytogfr.2013.06.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 06/18/2013] [Accepted: 06/19/2013] [Indexed: 02/06/2023]
Abstract
TGFβ is secreted in a latent state and must be "activated" by molecules that facilitate its release from a latent complex and allow binding to high affinity cell surface receptors. Numerous molecules have been implicated as potential mediators of this activation process, but only a limited number of these activators have been demonstrated to play a role in TGFβ mobilisation in vivo. Here we review the process of TGFβ secretion and activation using evolutionary data, sequence conservation and structural information to examine the molecular mechanisms by which TGFβ is secreted, sequestered and released. This allows the separation of more ancient TGFβ activators from those factors that emerged more recently, and helps to define a potential hierarchy of activation mechanisms.
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Affiliation(s)
- Ian B Robertson
- Department of Cell Biology, New York University School of Medicine, 550 First Avenue, Cell Biology Floor 6 Room 650, Medical Science Building, New York, NY 10016, United States.
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22
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Bultmann I, Conradi A, Kretschmer C, Sterner-Kock A. Latent transforming growth factor β-binding protein 4 is downregulated in esophageal cancer via promoter methylation. PLoS One 2013; 8:e65614. [PMID: 23741501 PMCID: PMC3669142 DOI: 10.1371/journal.pone.0065614] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 04/26/2013] [Indexed: 02/07/2023] Open
Abstract
Latent transforming growth factor β-binding protein 4 (LTBP4) is an extracellular matrix molecule that is a member of important connective tissue networks and is needed for the correct folding and the secretion of TGF-β1. LTBP4 is downregulated in carcinomas of various tissues. Here we show that LTBP4 is also downregulated in adenocarcinomas and squamous cell carcinomas of the esophagus in vitro and in vivo. Re-expression of LTBP4 in esophageal cancer cell lines reduced cell migration ability, whereas cell viability and cell proliferation remained unchanged. Hypermethylation of the promoter regions of the two main human LTBP4 transcriptional forms, LTBP4L and LTBP4S, was found to be involved in LTBP4 silencing. Detailed investigations of the methylation patterns of the promoter regions of LTBP4L and LTBP4S identified GATA1, SP1, E2F4 and SMAD3 as potential transcription factors involved in LTBP4 expression. In in vitro transcription factor activity studies we discovered E2F4 as novel powerful regulator for LTBP4S expression.
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Affiliation(s)
- Insa Bultmann
- Center for Experimental Medicine, Medical Faculty, University of Cologne, Cologne, Germany
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23
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Latent TGF-β binding protein 4 promotes elastic fiber assembly by interacting with fibulin-5. Proc Natl Acad Sci U S A 2013; 110:2852-7. [PMID: 23382201 DOI: 10.1073/pnas.1215779110] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Elastic fiber assembly requires deposition of elastin monomers onto microfibrils, the mechanism of which is incompletely understood. Here we show that latent TGF-β binding protein 4 (LTBP-4) potentiates formation of elastic fibers through interacting with fibulin-5, a tropoelastin-binding protein necessary for elastogenesis. Decreased expression of LTBP-4 in human dermal fibroblast cells by siRNA treatment abolished the linear deposition of fibulin-5 and tropoelastin on microfibrils. It is notable that the addition of recombinant LTBP-4 to cell culture medium promoted elastin deposition on microfibrils without changing the expression of elastic fiber components. This elastogenic property of LTBP-4 is independent of bound TGF-β because TGF-β-free recombinant LTBP-4 was as potent an elastogenic inducer as TGF-β-bound recombinant LTBP-4. Without LTBP-4, fibulin-5 and tropoelastin deposition was discontinuous and punctate in vitro and in vivo. These data suggest a unique function for LTBP-4 during elastic fibrogenesis, making it a potential therapeutic target for elastic fiber regeneration.
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24
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Abstract
Latent transforming growth factor beta (TGF-β) binding proteins (LTBPs) are large extracellular glycoproteins structurally similar to fibrillins. They perform intricate and important roles in the extracellular matrix (ECM) and perturbations of their function manifest as a wide range of diseases. LTBPs are major regulators of TGF-β bioavailability and action. In addition, LTBPs interact with other ECM proteins-from cytokines to large multi-factorial aggregates like microfibrils and elastic fibers, affecting their genesis, structure, and performance. In the present article, we review recent advancements in the field and relate the complex roles of LTBP in development and homeostasis.
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Affiliation(s)
- Vesna Todorovic
- Department of Cell Biology, NYU Langone Medical Center, New York, New York 10016, USA.
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25
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Swaggart KA, Heydemann A, Palmer AA, McNally EM. Distinct genetic regions modify specific muscle groups in muscular dystrophy. Physiol Genomics 2010; 43:24-31. [PMID: 20959497 DOI: 10.1152/physiolgenomics.00172.2010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Phenotypic expression in the muscular dystrophies is variable, even with the identical mutation, providing strong evidence that genetic modifiers influence outcome. To identify genetic modifier loci, we used quantitative trait locus mapping in two differentially affected mouse strains with muscular dystrophy. Using the Sgcg model of limb girdle muscular dystrophy that lacks the dystrophin-associated protein γ-sarcoglycan, we evaluated chromosomal regions that segregated with two distinct quantifiable characteristics of muscular dystrophy, membrane permeability and fibrosis. We previously identified a single major locus on murine chromosome 7 that influences both traits of membrane permeability and fibrosis in the quadriceps muscle. Using a larger cohort, we now found that this same interval strongly associated with both traits in all limb skeletal muscle groups studied, including the gastrocnemius/soleus, gluteus/hamstring, and triceps muscles. In contrast, the muscles of the trunk were modified by distinct genetic loci, possibly reflecting the embryological origins and physiological stressors unique to these muscle groups. A locus on chromosome 18 was identified that modified membrane permeability of the abdominal muscles, and a locus on chromosome 3 was found that regulated diaphragm and abdominal muscle fibrosis. Fibrosis in the heart associated with a region on chromosome 9 and likely reflects differential function between cardiac and skeletal muscle. These data underscore the complexity of inheritance and penetrance of single-gene disorders.
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