The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Robert P Mecham - One of the best experts on this subject based on the ideXlab platform.
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Elastic Fiber ultrastructure and assembly
Matrix Biology, 2019Co-Authors: Beth A Kozel, Robert P MechamAbstract:Abstract Studies over the years have described a filamentous structure to mature elastin that suggests a complicated packing arrangement of tropoelastin subunits. The currently accepted mechanism for tropoelastin assembly requires microfibrils to serve as a physical extracellular scaffold for alignment of tropoelastin monomers during and before crosslinking. However, recent evidence suggests that the initial stages of tropoelastin assembly occur within the cell or at unique assembly sites on the plasma membrane where tropoelastin self assembles to form elastin aggregates. Outside the cell, elastin aggregates transfer to growing Elastic Fibers in the extracellular matrix where tensional forces on microfibrils generated through cell movement help shape the growing Fiber. Overall, these observations challenge the widely held idea that interaction between monomeric tropoelastin and microfibrils is a requirement for elastin assembly, and point to self-assembly of tropoelastin as a driving force in elastin maturation.
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fibulin 4 e57k knock in mice recapitulate cutaneous vascular and skeletal defects of recessive cutis laxa 1b with both Elastic Fiber and collagen fibril abnormalities
Journal of Biological Chemistry, 2015Co-Authors: Olga Igoucheva, Vitali Alexeev, Carmen M Halabi, Sheila M Adams, Machiko Arita, Adele Donahue, Robert P Mecham, Ivan Stoilov, Takako Sasaki, David E BirkAbstract:Abstract Fibulin-4 is an extracellular matrix protein essential for Elastic Fiber formation. Frameshift and missense mutations in the fibulin-4 gene (EFEMP2/FBLN4) cause autosomal recessive cutis laxa (ARCL) 1B, characterized by loose skin, aortic aneurysm, arterial tortuosity, lung emphysema and skeletal abnormalities. Homozygous missense mutations in FBLN4 are a prevalent cause of ARCL 1B. Here we generated a knock-in mouse strain bearing a recurrent fibulin-4 E57K homozygous missense mutation. The mutant mice survived into adulthood and displayed abnormalities in multiple organ systems, including loose skin, bent forelimb, aortic aneurysm, tortuous artery and pulmonary emphysema. Biochemical studies of dermal fibroblasts showed that fibulin-4 E57K mutant protein was produced, but was prone to dimer formation and inefficiently secreted, thereby triggering an endoplasmic reticulum stress response. Immunohistochemistry detected a low level of fibulin-4 E57K protein in the knock-in skin along with altered expression of selected Elastic Fiber components. Processing of a precursor to mature lysyl oxidase, an enzyme involved in crosslinking of elastin and collagen, was compromised. The knock-in skin had a reduced level of desmosine, an elastin-specific crosslink compound, and ultrastructurally abnormal Elastic Fibers. Surprisingly, structurally aberrant collagen fibrils and altered organization into Fibers were characteristics of the knock-in dermis and forelimb tendons. Type I collagen extracted from the knock-in skin had decreased amounts of covalent intermolecular crosslinks, which could contribute to the collagen fibril abnormalities. Our studies provide the first evidence that fibulin-4 plays a role in regulating collagen fibril assembly and offer a preclinical platform for developing treatments for ARCL 1B.
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Oxidative and Nitrosative Modifications of Tropoelastin Prevent Elastic Fiber Assembly in Vitro
The Journal of biological chemistry, 2010Co-Authors: Kamal Akhtar, Robert P Mecham, Barry Starcher, Thomas J. Broekelmann, Ming Miao, Fred W. Keeley, Richard A. Pierce, Tracy L. Adair-kirkAbstract:Elastic Fibers are extracellular structures that provide stretch and recoil properties of tissues, such as lungs, arteries, and skin. Elastin is the predominant component of Elastic Fibers. Tropoelastin (TE), the precursor of elastin, is synthesized mainly during late fetal and early postnatal stages. The turnover of elastin in normal adult tissues is minimal. However, in several pathological conditions often associated with inflammation and oxidative stress, elastogenesis is re-initiated, but newly synthesized Elastic Fibers appear abnormal. We sought to determine the effects of reactive oxygen and nitrogen species (ROS/RNS) on the assembly of TE into Elastic Fibers. Immunoblot analyses showed that TE is oxidatively and nitrosatively modified by peroxynitrite (ONOO−) and hypochlorous acid (HOCl) and by activated monocytes and macrophages via release of ONOO− and HOCl. In an in vitro Elastic Fiber assembly model, oxidatively modified TE was unable to form Elastic Fibers. Oxidation of TE enhanced coacervation, an early step in Elastic Fiber assembly, but reduced cross-linking and interactions with other proteins required for Elastic Fiber assembly, including fibulin-4, fibulin-5, and fibrillin-2. These findings establish that ROS/RNS can modify TE and that these modifications affect the assembly of Elastic Fibers. Thus, we speculate that oxidative stress may contribute to the abnormal structure and function of Elastic Fibers in pathological conditions.
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New insights into Elastic Fiber assembly
Birth defects research. Part C Embryo today : reviews, 2007Co-Authors: Jessica E. Wagenseil, Robert P MechamAbstract:Elastic Fibers provide recoil to tissues that undergo repeated stretch, such as the large arteries and lung. These large extracellular matrix (ECM) structures contain numerous components, and our understanding of Elastic Fiber assembly is changing as we learn more about the various molecules associated with the assembly process. The main components of Elastic Fibers are elastin and microfibrils. Elastin makes up the bulk of the mature Fiber and is encoded by a single gene. Microfibrils consist mainly of fibrillin, but also contain or associate with proteins such as microfibril associated glycoproteins (MAGPs), fibulins, and EMILIN-1. Microfibrils were thought to facilitate alignment of elastin monomers prior to cross-linking by lysyl oxidase (LOX). We now know that their role, as well as the overall assembly process, is more complex. Elastic Fiber formation involves elaborate spatial and temporal regulation of all of the involved proteins and is difficult to recapitulate in adult tissues. This report summarizes the known interactions between elastin and the microfibrillar proteins and their role in Elastic Fiber assembly based on in vitro studies and evidence from knockout mice. We also propose a model of Elastic Fiber assembly based on the current data that incorporates interactions between elastin, LOXs, fibulins and the microfibril, as well as the pivotal role played by cells in structuring the final functional Fiber.
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Microfibril-associated MAGP-2 stimulates Elastic Fiber assembly
The Journal of biological chemistry, 2006Co-Authors: Raphael Lemaire, Robert P Mecham, Julie Bayle, Robert LafyatisAbstract:Abstract Elastic Fibers are complex structures composed of a tropoelastin inner core and microfibril outer mantle guiding tropoelastin deposition. Microfibrillar proteins mainly include fibrillins and microfibril-associated glycoproteins (MAGPs). MAGP-2 exhibits developmental expression peaking at Elastic Fiber onset, suggesting that MAGP-2 mediates Elastic Fiber assembly. To determine whether MAGP-2 regulates Elastic Fiber assembly, we used an in vitro model featuring doxycycline-regulated cells conditionally overexpressing exogenous MAGP-2 and constitutively expressing enhanced green fluorescent protein-tagged tropoelastin. Analysis by immunofluorescent staining showed that MAGP-2 overexpression dramatically increased Elastic Fibers levels, independently of extracellular levels of soluble tropoelastin, indicating that MAGP-2 stimulates Elastic Fiber assembly. This was associated with increased levels of matrix-associated MAGP-2. Electron microscopy showed that MAGP-2 specifically associates with microfibrils and that elastin globules primarily colocalize with MAGP-2-associated microfibrils, suggesting that microfibril-associated MAGP-2 facilitates Elastic Fiber assembly. MAGP-2 overexpression did not change levels of matrix-associated fibrillin-1, MAGP-1, fibulin-2, fibulin-5, or emilin-1, suggesting that microfibrils and other Elastic Fiberassociated proteins known to regulate elastogenesis do not mediate MAGP-2-induced Elastic Fiber assembly. Moreover, mutation analysis showed that MAGP-2 does not stimulate Elastic Fiber assembly through its RGD motif, suggesting that integrin receptor binding does not mediate MAGP-2-induced Elastic Fiber assembly. Because MAGP-2 interacts with Jagged-1 that controls cell-matrix interaction and cell motility, two key factors in Elastic Fiber macroassembly, microfibril-associated MAGP-2 may stimulate Elastic Fiber macroassembly by targeting the release of elastin globules from the cell membrane onto developing Elastic Fibers.
Yan Huang - One of the best experts on this subject based on the ideXlab platform.
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high performance stretchable yarn supercapacitor based on ppy cnts urethane Elastic Fiber core spun yarn
Nano Energy, 2016Co-Authors: Yan Huang, Chenxi Fu, Zhengyue Wang, Yang Huang, Hong HuAbstract:Abstract Yarn supercapacitors, as knittable and weavable energy storage devices, are attracting more and more attention in recent years. Similar to various yarns with different physical and mechanical properties available in textile industry, different yarn supercapacitors should be developed as well. However, as a device, stretchable yarn supercapacitors suffer a lot from limited stretchability, complicated and high cost fabrication, which greatly restrict their wide adoptions. Here, we use urethane Elastic Fiber core spun yarns (UY) with intrinsic high stretchability for the first time, as a wearable scaffold for hosting conductive CNT and electrocapacitive PPy to fabricate large-scale highly stretchable yarn electrodes via a simple two-step process (CNTs dipping and PPy electrodeposition). The yarn supercapacitor keeps the excellent stretchability of the UY without using any extra stretchy substrate or wavy structure as most stretchable yarn supercapacitors used, and at the same time, exhibits a high areal capacitance of 69 mF cm −2 (normalized to two electrodes) as well as a good rate capacity. Furthermore, the capacitive performance of the yarn supercapacitor remains nearly unchanged even at a high strain of 80%. The high-performance stretchable yarn supercapacitor with the use of intrinsically stretchable yarns paves a way for the production of large-size fabrics for wearable electronic applications.
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High-performance stretchable yarn supercapacitor based on PPy@CNTs@urethane Elastic Fiber core spun yarn
Nano Energy, 2016Co-Authors: Jinfeng Sun, Zhengyue Wang, Yang Huang, Yan Huang, Minshen Zhu, Chunyi ZhiAbstract:Abstract Yarn supercapacitors, as knittable and weavable energy storage devices, are attracting more and more attention in recent years. Similar to various yarns with different physical and mechanical properties available in textile industry, different yarn supercapacitors should be developed as well. However, as a device, stretchable yarn supercapacitors suffer a lot from limited stretchability, complicated and high cost fabrication, which greatly restrict their wide adoptions. Here, we use urethane Elastic Fiber core spun yarns (UY) with intrinsic high stretchability for the first time, as a wearable scaffold for hosting conductive CNT and electrocapacitive PPy to fabricate large-scale highly stretchable yarn electrodes via a simple two-step process (CNTs dipping and PPy electrodeposition). The yarn supercapacitor keeps the excellent stretchability of the UY without using any extra stretchy substrate or wavy structure as most stretchable yarn supercapacitors used, and at the same time, exhibits a high areal capacitance of 69 mF cm −2 (normalized to two electrodes) as well as a good rate capacity. Furthermore, the capacitive performance of the yarn supercapacitor remains nearly unchanged even at a high strain of 80%. The high-performance stretchable yarn supercapacitor with the use of intrinsically stretchable yarns paves a way for the production of large-size fabrics for wearable electronic applications.
Chunyi Zhi - One of the best experts on this subject based on the ideXlab platform.
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High-performance stretchable yarn supercapacitor based on PPy@CNTs@urethane Elastic Fiber core spun yarn
Nano Energy, 2016Co-Authors: Jinfeng Sun, Zhengyue Wang, Yang Huang, Yan Huang, Minshen Zhu, Chunyi ZhiAbstract:Abstract Yarn supercapacitors, as knittable and weavable energy storage devices, are attracting more and more attention in recent years. Similar to various yarns with different physical and mechanical properties available in textile industry, different yarn supercapacitors should be developed as well. However, as a device, stretchable yarn supercapacitors suffer a lot from limited stretchability, complicated and high cost fabrication, which greatly restrict their wide adoptions. Here, we use urethane Elastic Fiber core spun yarns (UY) with intrinsic high stretchability for the first time, as a wearable scaffold for hosting conductive CNT and electrocapacitive PPy to fabricate large-scale highly stretchable yarn electrodes via a simple two-step process (CNTs dipping and PPy electrodeposition). The yarn supercapacitor keeps the excellent stretchability of the UY without using any extra stretchy substrate or wavy structure as most stretchable yarn supercapacitors used, and at the same time, exhibits a high areal capacitance of 69 mF cm −2 (normalized to two electrodes) as well as a good rate capacity. Furthermore, the capacitive performance of the yarn supercapacitor remains nearly unchanged even at a high strain of 80%. The high-performance stretchable yarn supercapacitor with the use of intrinsically stretchable yarns paves a way for the production of large-size fabrics for wearable electronic applications.
Hong Hu - One of the best experts on this subject based on the ideXlab platform.
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high performance stretchable yarn supercapacitor based on ppy cnts urethane Elastic Fiber core spun yarn
Nano Energy, 2016Co-Authors: Yan Huang, Chenxi Fu, Zhengyue Wang, Yang Huang, Hong HuAbstract:Abstract Yarn supercapacitors, as knittable and weavable energy storage devices, are attracting more and more attention in recent years. Similar to various yarns with different physical and mechanical properties available in textile industry, different yarn supercapacitors should be developed as well. However, as a device, stretchable yarn supercapacitors suffer a lot from limited stretchability, complicated and high cost fabrication, which greatly restrict their wide adoptions. Here, we use urethane Elastic Fiber core spun yarns (UY) with intrinsic high stretchability for the first time, as a wearable scaffold for hosting conductive CNT and electrocapacitive PPy to fabricate large-scale highly stretchable yarn electrodes via a simple two-step process (CNTs dipping and PPy electrodeposition). The yarn supercapacitor keeps the excellent stretchability of the UY without using any extra stretchy substrate or wavy structure as most stretchable yarn supercapacitors used, and at the same time, exhibits a high areal capacitance of 69 mF cm −2 (normalized to two electrodes) as well as a good rate capacity. Furthermore, the capacitive performance of the yarn supercapacitor remains nearly unchanged even at a high strain of 80%. The high-performance stretchable yarn supercapacitor with the use of intrinsically stretchable yarns paves a way for the production of large-size fabrics for wearable electronic applications.
Zhengyue Wang - One of the best experts on this subject based on the ideXlab platform.
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high performance stretchable yarn supercapacitor based on ppy cnts urethane Elastic Fiber core spun yarn
Nano Energy, 2016Co-Authors: Yan Huang, Chenxi Fu, Zhengyue Wang, Yang Huang, Hong HuAbstract:Abstract Yarn supercapacitors, as knittable and weavable energy storage devices, are attracting more and more attention in recent years. Similar to various yarns with different physical and mechanical properties available in textile industry, different yarn supercapacitors should be developed as well. However, as a device, stretchable yarn supercapacitors suffer a lot from limited stretchability, complicated and high cost fabrication, which greatly restrict their wide adoptions. Here, we use urethane Elastic Fiber core spun yarns (UY) with intrinsic high stretchability for the first time, as a wearable scaffold for hosting conductive CNT and electrocapacitive PPy to fabricate large-scale highly stretchable yarn electrodes via a simple two-step process (CNTs dipping and PPy electrodeposition). The yarn supercapacitor keeps the excellent stretchability of the UY without using any extra stretchy substrate or wavy structure as most stretchable yarn supercapacitors used, and at the same time, exhibits a high areal capacitance of 69 mF cm −2 (normalized to two electrodes) as well as a good rate capacity. Furthermore, the capacitive performance of the yarn supercapacitor remains nearly unchanged even at a high strain of 80%. The high-performance stretchable yarn supercapacitor with the use of intrinsically stretchable yarns paves a way for the production of large-size fabrics for wearable electronic applications.
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High-performance stretchable yarn supercapacitor based on PPy@CNTs@urethane Elastic Fiber core spun yarn
Nano Energy, 2016Co-Authors: Jinfeng Sun, Zhengyue Wang, Yang Huang, Yan Huang, Minshen Zhu, Chunyi ZhiAbstract:Abstract Yarn supercapacitors, as knittable and weavable energy storage devices, are attracting more and more attention in recent years. Similar to various yarns with different physical and mechanical properties available in textile industry, different yarn supercapacitors should be developed as well. However, as a device, stretchable yarn supercapacitors suffer a lot from limited stretchability, complicated and high cost fabrication, which greatly restrict their wide adoptions. Here, we use urethane Elastic Fiber core spun yarns (UY) with intrinsic high stretchability for the first time, as a wearable scaffold for hosting conductive CNT and electrocapacitive PPy to fabricate large-scale highly stretchable yarn electrodes via a simple two-step process (CNTs dipping and PPy electrodeposition). The yarn supercapacitor keeps the excellent stretchability of the UY without using any extra stretchy substrate or wavy structure as most stretchable yarn supercapacitors used, and at the same time, exhibits a high areal capacitance of 69 mF cm −2 (normalized to two electrodes) as well as a good rate capacity. Furthermore, the capacitive performance of the yarn supercapacitor remains nearly unchanged even at a high strain of 80%. The high-performance stretchable yarn supercapacitor with the use of intrinsically stretchable yarns paves a way for the production of large-size fabrics for wearable electronic applications.