The N-terminal head caps an extended coil region that consists of domains 2-18. Aaron, B., and Gosline, J. 26, 115124. doi: 10.1371/journal.pone.0046130, Hedtke, T., Schrader, C. U., Heinz, A., Hoehenwarter, W., Brinckmann, J., Groth, T., et al. The narrow specificity to v3 and 53 may also be beneficial compared with other ECM adhesion molecules such as fibronectin (which can adhere to up to 20 types of integrin) which may compete with and modulate binding to tropoelastin, and deliver opposing effects on cell proliferation. Matrix Biol. J. Biol. Chem. Acad. Elastagens revolutionary recombinant human tropoelastin, is identical to that present in human tissue and has many clinical applications, including effective breakthrough treatments for acne scars, stretch marks, aesthetic skin repair and wound repair. Specific instructions are found in the Directions for Use. Biochemistry 36, 84138421. *Correspondence: Anthony S. Weiss, tony.weiss@sydney.edu.au, These authors have contributed equally to this work, Fibrous Assemblies: From Synthesis and Nanostructure Characterization to Materials Development and Application, Front. Biochimie 86, 173178. Structural changes and facilitated association of tropoelastin. The Wellcome Trust Centre for Cell-Matrix Research is supported by funding from Wellcome Trust (203128/Z/16/Z). Tropoelastins C-terminal domain 36 (yellow) does not fall into either category as it contains a distinct sequence capped with a Gly-Arg-Lys-Arg-Lys (GRKRK) motif and is primarily involved in cell interactions. 28, 379382. 289, 489492. Primary structure of porcine tropoelastin. Tropoelastin: a novel marker for plaque progression and instability. J. Biochem. Modulative effects are also observed within full length tropoelastin, where disruptions to domain 26 diminish self-assembly (Jensen et al., 2000), highlighting the context of primary sequence on higher order structures. A model two-component system for studying the architecture of elastin assembly in vitro. Elastic fibers are composed of approximately 90% elastin, whilst the remaining components are primarily comprised of fibrillin glycoproteins (Mecham, 1991). II. J. Biol. It has been postulated that the interaction between tropoelastin and cell surface proteoglycans is part of the assembly process of elastin before it is deposited on microfibrils. Molecular modeling of protein materials: case study of elastin. Characterization of the complete human elastin gene. J. Biochem. Mol. Importantly, the presence of fibrils indicates that the nanostructures formed during initial assembly contribute to the supramolecular structures that arise during both early (spherule) and later (fibril) stages of elastogenesis. doi: 10.1016/j.matbio.2007.05.005, He, D., Miao, M., Sitarz, E. E., Muiznieks, L. D., Reichheld, S., Stahl, R. J., et al. doi: 10.1161/circimaging.117.007303, Prhashanna, A., Taylor, P. A., Qin, J., Kiick, K. L., and Jayaraman, A. Soluble matrix protein is a potent modulator of mesenchymal stem cell Tropoelastin was revealed to be an asymmetric molecule with distinct N- and C-terminal regions that are respectively referred to as the head and foot of the molecule. Thermal compaction of disordered and elastin-like polypeptides: a temperature-dependent, sequence-specific coarse-grained simulation model. Shape of tropoelastin, the highly extensible protein that - PNAS Pathol. Trifluoroethanol may form a solvent matrix for assisted hydrophobic interactions between peptide side chains. Additionally, coarse-graining the full-atomistic model has allowed for the examination of mesoscale tropoelastin assembly and, in particular, deciphered the orientation of tropoelastin molecules that occurs during early stage assembly (inset image) (Tarakanova et al., 2019a). Instead, tropoelastin domains 1418 and 36 (RKRK sequence) have been found to bind to both integrins. (2014). Natl. J. Biomol. 278, 4855348562. Tropoelastin spherules assemble at the cell surface before deposition onto the microfibrillar scaffold in cell culture systems at physiological temperature (Kozel et al., 2006). Detailed Description: Unlike hydrophobic domains, cross-linking domains in isolation are unable to self-assemble; thus, they have been studied in the context of the cross-linking of elastin-derived biomaterials (Annabi et al., 2017; Yue et al., 2017). Acta Biomater. (1995). doi: 10.1002/jcp.20546, Kozel, B. (2019b). For Allergan, contact: Lisa Brown 1-862-261-7320, 1985 - 2023 BioSpace.com. Coacervation involves the agglomeration of protein molecules, which is an . The bifunctional cross-links can undergo further condensation to form tetrafunctional desmosine or isodesmosine (Partridge, 1966). 33, 54685481. For many years it was difficult to study tropoelastin at an atomic scale, but the application of computational methods, such as full-atomistic molecular dynamics and elastic network models, in combination with powerful low-resolution structural studies, have expanded the field and delivered an enhanced understanding of the mechanisms that contribute to self-assembly. Cross-linking domains can be subdivided into KP or KA domains, which denote the amino acids (proline or alanine, respectively) that are adjacent to the lysines (Figure 1). 84, 6880. In order to eliminate this limitation, human tropoelastin has been expressed in a recombinant bacterial system and the protein has been highly purified. 67-kD elastin-binding protein is a protective companion of extracellular insoluble elastin and intracellular tropoelastin. Crosslinking [ edit] A new amino acid from hydrolysates of elastin. 300, 13351359. Domain 26 of tropoelastin plays a dominant role in association by coacervation. 27, 441450. The elastin receptor complex transduces signals through the catalytic activity of its Neu-1 subunit. Evidence for the presence of alpha-aminoadipic acid delta-semialdehyde and its aldol condensation product. (1988). Rush to Beauty Anticipates New Line of Dermal Fillers from Allergan Coacervation of tropoelastin. The conversion of a single lysine to an allysine results in structural stabilization, which may serve as a checkpoint during self-assembly to ensure that molecules incapable of forming multiple cross-links are not incorporated into the growing chain. Thus, elastin is responsible, in great part, for the properties of elastic fibers. Molecular docking studies utilizing tropoelastin and the 3D structure of LOX1 (Vallet et al., 2018) may assist in our understanding as to whether the enzyme has a preference for modifying particular tropoelastin residues. doi: 10.1007/978-3-319-71530-8_13-1, Wen, Q., Mithieux, S. M., and Weiss, A. S. (2020). Elastin is a critical skin protein consisting of crosslinked tropoelastin. 9:643110. doi: 10.3389/fbioe.2021.643110. On the cell surface, EBP forms a complex with protective protein/cathepsin A (PPCA) and neuraminidase-1 (Neu-1), giving rise to the ERC (Duca et al., 2007). By probing mutations in computational studies that resolve the atomistic structure of the molecule, the deduction of mechanisms associated with changes to functional roles of specific domains has become feasible, and a connection between local structures and biological performance can be established (Figure 2; Tarakanova et al., 2018). Our Juvederm collection of fillers has sales of over $1 billion globally and is one of the fastest growing parts of our Aesthetics business, said Bill Meury, Chief Commercial Officer at Allergan. doi: 10.1073/pnas.1701877114, Reichheld, S. E., Muiznieks, L. D., Lu, R., Sharpe, S., and Keeley, F. W. (2019). Biopolymers 107:e23007. (2006). We are very interested in the blend of biochemistry and cell biology, as well as the tissue engineering and regenerative medicine opportunities provided by this amazing elastic protein. doi: 10.1074/jbc.RA118.004322, Shapiro, S., Endicott, S., Province, M., Pierce, J., and Campbell, E. (1991). J. Bioeng. doi: 10.1021/bi00835a021, Gray, W. R., Sandberg, L. B., and Foster, J. 207, 8796. Biotechnol. doi: 10.1006/jmbi.1995.0502, Yeo, G. C., Baldock, C., Tuukkanen, A., Roessle, M., Dyksterhuis, L. B., Wise, S. G., et al. However, there are aspects of this model that warrant further investigation. doi: 10.1111/j.1749-6632.1991.tb17013.x, Mecham, R. P., Levy, B. D., Morris, S. L., Madaras, J. G., and Wrenn, D. S. (1985). Exp. Interestingly, the location and orientation of different domains that contacted each other during self-assembly was noted to be heterogeneous, resulting in head-to-head, tail-to-tail, head-to-tail, and lateral interactions (Tarakanova et al., 2019a). Arch. Of most importance, the inability to acquire large quantities of pure tropoelastin historically presented a significant obstacle to experimentally characterizing its structure. Tropoelastin is frequently described in the literature as an unstructured protein, mainly because models of elasticity invoke an element of disorder within the structure (4, 9, 10).While this concept appears to be the case at the fine, more subtle intramolecular level, chaos alone is unlikely to explain the ordered assembly of tropoelastin which culminates in the formation of organized . 41, 494497. The last 17 amino acid residues of the C-terminus of domain 36 are also implicated in HS interactions; the last four residues are Arg-Lys-Arg-Lys and are positively charged at physiological pH which provides a charged cluster capable of binding negatively charged HS (Broekelmann et al., 2005). doi: 10.1016/j.biomaterials.2017.01.041, Tarakanova, A., Ozsvar, J., Weiss, A. S., and Buehler, M. J. Elastogenesis is the term that collectively describes the hierarchical process of elastic fiber formation, and is comprised of distinct phases: tropoelastin synthesis, coacervation, cross-linking, and deposition. (2018). 264, 88878891. The evolutionary background and functional consequences of the rs2071307 polymorphism in human tropoelastin. The business could generate net sales of approximately $7 to $8 billion in 2025 from $3.8 billion in 2017. Calorim. (2011). Such models could be used in conjunction with the full molecular model of tropoelastin to examine the self-assembly of discrete regions to understand the impacts of amino acid substitutions in disease. This reflects the experimentally observed heterogeneity of cross-links in mature elastin, again giving weight to the hypothesis that the flexibility of tropoelastin is imperative for assembly (Schrader et al., 2018; Tarakanova et al., 2019a). Protein Eng. Thus, at lower temperatures, the water surrounding these domains forms ordered, clathrate-like shells that prevent aggregation until the appropriate temperature is reached (Wu and Weiss, 1999; Miao et al., 2003; Dandurand et al., 2015). Biopolymers [Epub ahead of print]. doi: 10.1038/246461a0, Haust, M. D., More, R. H., Bencosme, S. A., and Balis, J. U. Scientists find way to heal scars left behind by heart attacks Matrix Biol. Characterization of an unusual tropoelastin with truncated C-terminus in the frog. For example, models involving single point mutations at negatively charged residues demonstrated both regional and global destabilization of tropoelastins structure, which were validated by SAXS structures (Yeo et al., 2012; Tarakanova et al., 2018). Elastagen is an exciting clinical-stage company with an advanced tissue repair platform based on tropoelastin. Tropoelastin cannot readily be prepared in quantity from natural sources and this has limited research in several important areas including structure/function relationships and fiber assembly. On a per-share basis, the Irving, Texas-based company said it had profit of 1 cent. doi: 10.1073/pnas.1801205115, Tarakanova, A., Yeo, G. C., Baldock, C., Weiss, A. S., and Buehler, M. J. Reichheld, S. E., Muiznieks, L. D., Keeley, F. W., and Sharpe, S. (2017). ACS Biomater. LOX and LOXL convert the -amino group of lysine to -aminoadipic acid -semialdehyde (allysine) (Schmelzer et al., 2019), which spontaneously undergo either a Schiff base reaction with a lysine, or two allysines crosslink through aldol condensation, to give rise to bifunctional crosslinks (Franzblau et al., 1969; Lent et al., 1969). Dominant driving factors of assembly were examined, including water, temperature and domain pair orientations. The elasticity of organs and tissues in vertebrates is due to the presence of elastin, and an insoluble protein whose soluble monomer, tropoelastin, is enzymatically cross-linked through -amino groups of lysine residues. The SAXS/SANS global shape of tropoelastin (Baldock et al., 2011) has been used to validate the full-atomistic computational model of tropoelastin through a geometric and topological comparison (Tarakanova et al., 2018). Clinical Relevance of Elastin in the Structure and Function of Skin 167, 94103. 98, 416. Trifluoroethanol promotes helix formation by destabilizing backbone exposure: desolvation rather than native hydrogen bonding defines the kinetic pathway of dimeric coiled coil folding. The process of tropoelastin aggregation is initially reversible, as spherules dissipate if the temperature is lowered (Clarke et al., 2006), however, maintenance of a physiological temperature results in maturation, which is indicated by spherule coalescence and the irreversible formation of fibrillar structures (Cox et al., 1974; Bressan et al., 1983; Mithieux et al., 2005). doi: 10.1016/j.bbrc.2010.05.013, Elvin, C. M., Carr, A. G., Huson, M. G., Maxwell, J. M., Pearson, R. D., Vuocolo, T., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). Elastases can be in the form of serine- (e.g., Ela-2), cysteine- (e.g., cathepsin I), or matrix metalloproteinases (MMP-2, -7, -9, and -12), and bioactive peptides include the VGVAPG peptide. Self-healing and thermoreversible rubber from supramolecular assembly. Elastagens tropoelastin is identical to that present in human tissue, and has many potential clinical applications, including treatment for acne scars, stretch marks, aesthetic skin repair and surgical wound repair. Lab. 4, 508524. U.S.A. 112, E4408E4415. Modeling has been verified using wet-bench methodologies, forming a robust suite of complementary methodologies that will undoubtedly become more prevalent for exploring the assembly of biological fibers over time. 120, 419426. A., Torres, A. R., Alvarez, V. L., and Janata, J. Possible role in nucleated assembly. 87, 18281834. Communication: coacervation of tropoelastin results in fiber formation. 624, 137146. doi: 10.1046/j.1432-1327.1998.2580001.x, Wang, Z., Liu, L., Mithieux, S. M., and Weiss, A. S. (2020). Cooperativity between the hydrophobic and cross-linking domains of elastin. doi: 10.1002/bip.1981.360200611. Bashir, M. M., Indik, Z., Yeh, H., Ornstein-Goldstein, N., Rosenbloom, J. C., Abrams, W., et al. Acad. It was first hypothesized that tropoelastin assembles in a head-to-tail manner similar to that of other ECM proteins such as collagen, which assembles into fibrils that subsequently associate laterally to form sheets and thicker fibers (Kadler, 2017). III. 29, 152159. 410, 317323. Elastin is extensively cross-linked and difficult to break apart into monomers even under harsh conditions, thus, initial strategies included feeding animals a copper deficient diet to prevent lysyl oxidase (LOX) cross-linking of tropoelastin; however, this proved inefficient and time consuming (Wise and Weiss, 2009; Tarakanova et al., 2018). The authors wrote and submitted this manuscript in response to an invitation by the Editor. Elastin binding protein (EBP) is a splice variant of -galactosidase, that recognizes the repetitive hydrophobic sequences (VGVAPG) of tropoelastin (Tajima et al., 1997). Tropoelastin is a unique protein with biochemical and physical properties that allow it to rapidly self-assemble into fibrous structures. Adv. (2018). Elastin, arterial mechanics, and cardiovascular disease Genet. Elastin: Structure, Function, Skin Care & Supplements - Cleveland Clinic A., Starcher, B. C., and Urry, D. W. (1974). Provides infrastructure for further development and following approval to commercialize Elastagens products, SYDNEY February 7th: Elastagen Pty Limited, a clinical stage company developing medical device products based on recombinant tropoelastin, today announced that it has entered into a definitive agreement under which Allergan, a leading global biopharmaceutical company, has agreed to acquire Elastagen for an upfront payment of US$95M plus contingent, commercial payments.. Fibulin-4 and -5, but not fibulin-2, are associated with tropoelastin deposition in elastin-producing cell culture. Domains 12 to 16 of tropoelastin promote cell attachment and spreading through interactions with glycosaminoglycan and integrins alphaV and alpha5beta1. The study is designed to evaluate the efficacy of two formulations of a cross-linked tropoelastin matrix given the product codes ELAPR002f (collectively referred to as ELAPR or ELAPR002) for the treatment of rolling atrophic acne scars when administered as intradermal implants. doi: 10.1021/acsbiomaterials.6b00564, Yeo, G. C., Keeley, F. W., and Weiss, A. S. (2011). How to Get LONGER Eyelashes - Guaranteed | NULASTIN Synthesis and properties of crosslinked recombinant pro-resilin. Coacervation characteristics of recombinant human tropoelastin. doi: 10.1038/nature06669, Cox, B. Conformational transitions of the cross-linking domains of elastin during self-assembly. Allergan to acquire University of Sydney spinoff Elastagen Cell Biol. 7:32. doi: 10.3389/fphar.2016.00032, Schmelzer, C. E. H., Heinz, A., Troilo, H., Lockhart-Cairns, M. P., Jowitt, T. A., Marchand, M. F., et al. J. Exp. 22, 109121. The human ELN gene is located on the long arm of chromosome 7q11.2 and comprises of 34 exons nestled between lengthy introns (Indik et al., 1987, 1989; Bashir et al., 1989). (2015). Rep. 8, 116. Cell Physiol. A., Rongish, B. J., Czirok, A., Zach, J., Little, C. D., Davis, E. C., et al. Increased cyclic GMP levels lead to a stimulation of elastin production in ligament fibroblasts that is reversed by cyclic AMP. Isolation and characterization of crosslinked peptides from elastin. Tropoelastin has 2 alternating domains: (1) hydrophilic, cross-linked, domains rich in Lys and Ala; and (2) hydrophobic domains (responsible for elasticity) rich in Val, Pro, and Gly, which often occur in repeats of VPGVG or VGGVG. Biomaterials 127, 4960. Adv. Sci. This suggests a high level of conformational sampling during this phase of coacervation, indicating that the flexibility of tropoelastin plays a key role in assembly that may persist, to some extent, into later stages of assembly (Reichheld et al., 2020). 432, 57365751. Furthermore, the SAXS/SANS structure has been mapped to an elastic network model with tunable stiffness to probe the role of tropoelastins flexibility in fiber assembly (Yeo et al., 2016). All rights reserved. doi: 10.1074/jbc.M308465200, Miao, M., Bruce, A. E., Bhanji, T., Davis, E. C., and Keeley, F. W. (2007). Am. J. Biol. These interactions trigger a wide range of processes including wound healing, elastogenesis and maintenance of stemness (Yeo and Weiss, 2019). Elastin synthesis in arterial smooth muscle cell culture. Elastagen Pty Ltd, a clinical stage company developing medical device products based on recombinant tropoelastin, today announced that it has entered into a definitive agreement under which Allergan plc, a leading global biopharmaceutical company, has agreed to acquire Elastagen. doi: 10.1203/00006450-199010000-00015, Nonaka, R., Sato, F., and Wachi, H. (2014). The company is particularly pointing to usage in the treatment of acne scars, stretch marks, aesthetic skin repair and surgical wound repair. 3, 4 Elastin has a very low rate of turnover, so it . doi: 10.1046/j.1432-1327.1999.00891.x, Yamauchi, Y., Tsuruga, E., Nakashima, K., Sawa, Y., and Ishikawa, H. (2010). J. Mol. 260, 32553258. doi: 10.1016/j.matbio.2009.10.003, Tu, Y., Wise, S. G., and Weiss, A. S. (2010). Additionally, elastin is remarkably durable as it is primarily deposited during prenatal development and childhood, and is rarely synthesized during adulthood. Co-author Professor Anthony Weiss from the Charles Perkins Centre and Faculty of Science explained: "Tropoelastin can repair the heart because it is a precise replica of the body's natural elastic protein,". Tropoelastin has a defined shape in solution but paradoxically also displays a large percentage of flexible, disordered regions needed for molecular elasticity (4, 5).The tertiary structure of human tropoelastin represents an ensemble of elastic conformers (3, 6), yet occasional conserved sequence elements hint at requirements for functional demands in one or more key parts of this molecule (7 . It is likely that, as a general rule, integrin binding to tropoelastin is mediated via GAGs, which is facilitated by the repetition of tropoelastins primary sequence and the surface exposure of positively charged similar domains (Lee et al., 2017; Bochicchio et al., 2021). (2012). Cell. Biopolymers 29, 16991706. Cross-linking requires the modification of at least one of the lysine participants by a member of the copper-containing LOX or lysine oxidase-like (LOXL) enzyme families. Proc. Our understanding of key aspects of the assembly process have been unclear due to the intrinsic properties of elastin and tropoelastin that render them difficult to study. Form. J. Biol. doi: 10.1016/j.str.2006.09.008, Rauscher, S., and Pomes, R. (2017). J. Biol. Insights into the structure and dynamics of lysyl oxidase propeptide, a flexible protein with numerous partners. A Study to Evaluate the Efficacy of ELAPR002f in Females and Males With Matrix 12, 156162. Eng. Elastin-like polypeptides as models of intrinsically disordered proteins. While the clinical stage tropoelastin platform provides multiple opportunities for aesthetics, scar remodelling and tissue repair, it also has the . doi: 10.1074/jbc.M501390200, Chung, M. I., Miao, M., Stahl, R. J., Chan, E., Parkinson, J., and Keeley, F. W. (2006). Figure 1. (1989). (1987). Proc. Tropoelastin was revealed to be an asymmetric molecule with distinct N- and C-terminal regions that are respectively referred to as the "head" and "foot" of the molecule. Tropoelastin monomers undergo self-assembly upon reaching the transition temperature through the aggregation of their hydrophobic domains (Wise et al., 2014). Transglutaminase-mediated cross-linking of tropoelastin to fibrillin stabilises the elastin precursor prior to elastic fibre assembly. Med. Attempts to characterize tropoelastins structure have seen a gradual shift from the belief that tropoelastins domains have fixed structures, to understanding that the majority of its domains are capable of transitioning between random coils and transient ordered structures. 38, 280291. Simul. Interactions with these integrins on the surface of mesenchymal stem cells, either through surface bound or as soluble tropoelastin, promote MSC proliferation and phenotypic maintenance via FAK and PKB/AKT (Yeo and Weiss, 2019). doi: 10.1074/jbc.M104985200, Toonkool, P., Jensen, S. A., Maxwell, A. L., and Weiss, A. S. (2001). (2020). (2013). Chemistry 10, 31663176. The smallest amino acid, glycine is known to promote flexibility within local structures due to lack of steric hindrance, whereas prolines restrictive sidechain inhibits conformational sampling and disrupts the formation of prolonged secondary structures (Roberts et al., 2015). Foster, J. 31, 261272. Differential scanning calorimetry studies of the inverse temperature transition of the polypentapeptide of elastin and its analogues. Tropoelastin bridge region positions the cell-interactive C terminus and contributes to elastic fiber assembly. Implications for tissue specificity and durability of elastic tissue. (2006). Eng. Tropoelastin is an ECM component primarily located in elastic tissues and has been shown to promote the expansion of hematopoietic stem cells (HSCs) and MSCs when used as a substrate coating or as part of the substrate bulk material ().The ECM is proposed to modulate stem cell phenotype and activity, including proliferation, via its chemistry, topography, and mechanical properties (). Elastin is the major component of elastic fibers, which are a major component of the tissue that supports the body's joints . (2020). Thus, computational approaches can be considered as important means to complement wet bench experiments. Received: 17 December 2020; Accepted: 08 February 2021;Published: 25 February 2021. With commercial operations in approximately 100 countries, Allergan is committed to working with physicians, healthcare providers and patients to deliver innovative and meaningful treatments that help people around the world live longer, healthier lives every day. 150, 154162. Elastin binding protein and FKBP65 modulate in vitro self-assembly of human tropoelastin. The isoform-function theory is further reinforced by the presence of two different ELN genes within teleosts that are differentially expressed both spatially and temporally during development (Miao et al., 2007). In contrast, higher temperatures allow the breaking of the hydrogen bonds of the ordered water, dissipating the clathrate shells and permitting the association of the hydrophobic domains (Yeo et al., 2011).