1
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Aarthy M, Hemalatha T, Suryalakshmi P, Vinoth V, Mercyjayapriya J, Shanmugam G, Ayyadurai N. Biomimetic design of fibril-forming non-immunogenic collagen like proteins for tissue engineering. Int J Biol Macromol 2024; 266:130999. [PMID: 38521303 DOI: 10.1016/j.ijbiomac.2024.130999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 02/29/2024] [Accepted: 03/17/2024] [Indexed: 03/25/2024]
Abstract
Collagen, a key component of extracellular matrix serves as a linchpin for maintaining structural integrity and functional resilience. Concerns over purity and immunogenicity of animal-derived collagens have spurred efforts to develop synthetic collagen-based biomaterials. Despite several collagen mimics, there remains limited exploration of non-immunogenic biomaterials with the capacity for effective self-assembly. To combat the lacuna, collagen like protein (CLP) variants were rationally designed and recombinantly expressed, incorporating human telopeptide sequences (CLP-N and CLP-NC) and bioactive binding sites (CLP-NB). Circular dichroism analyses of the variants confirmed the triple helical conformation, with variations in thermal stability and conformation attributed to the presence of telopeptides at one or both ends of CLP. The variants had propensity to form oligomers, setting the stage for fibrillogenesis. The CLP variants were biocompatible, hemocompatible and supported cell proliferation and migration, particularly CLP-NB with integrin-binding sites. Gene expression indicated a lack of significant upregulation of inflammatory markers, highlighting the non-immunogenic nature of these variants. Lyophilized CLP scaffolds maintained their triple-helical structure and offered favorable biomaterial characteristics. These results accentuate the potential of designed CLP variants in tissue engineering, regenerative medicine and industrial sectors, supporting the development of biocompatible scaffolds and implants for therapeutic and cosmetic purposes.
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Affiliation(s)
- Mayilvahanan Aarthy
- Department of Biochemistry and Biotechnology, Council of Scientific and Industrial Research (CSIR) - Central Leather Research Institute (CLRI), Chennai 600020, India
| | - Thiagarajan Hemalatha
- Department of Biochemistry and Biotechnology, Council of Scientific and Industrial Research (CSIR) - Central Leather Research Institute (CLRI), Chennai 600020, India
| | - Pandurangan Suryalakshmi
- Department of Biochemistry and Biotechnology, Council of Scientific and Industrial Research (CSIR) - Central Leather Research Institute (CLRI), Chennai 600020, India
| | - Vetrivel Vinoth
- Department of Organic and Bioorganic Chemistry, CSIR-CLRI, Chennai 600020, India
| | - Jebakumar Mercyjayapriya
- Department of Biochemistry and Biotechnology, Council of Scientific and Industrial Research (CSIR) - Central Leather Research Institute (CLRI), Chennai 600020, India
| | - Ganesh Shanmugam
- Department of Organic and Bioorganic Chemistry, CSIR-CLRI, Chennai 600020, India
| | - Niraikulam Ayyadurai
- Department of Biochemistry and Biotechnology, Council of Scientific and Industrial Research (CSIR) - Central Leather Research Institute (CLRI), Chennai 600020, India.
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2
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Nagarajan MB, Ainscough AJ, Reynolds DS, Uzel SGM, Bjork JW, Baker BA, McNulty AK, Woulfe SL, Lewis JA. Biomimetic human skin model patterned with rete ridges. Biofabrication 2023; 16:015006. [PMID: 37734324 DOI: 10.1088/1758-5090/acfc29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 09/21/2023] [Indexed: 09/23/2023]
Abstract
Rete ridges consist of undulations between the epidermis and dermis that enhance the mechanical properties and biological function of human skin. However, most human skin models are fabricated with a flat interface between the epidermal and dermal layers. Here, we report a micro-stamping method for producing human skin models patterned with rete ridges of controlled geometry. To mitigate keratinocyte-induced matrix degradation, telocollagen-fibrin matrices with and without crosslinks enable these micropatterned features to persist during longitudinal culture. Our human skin model exhibits an epidermis that includes the following markers: cytokeratin 14, p63, and Ki67 in the basal layer, cytokeratin 10 in the suprabasal layer, and laminin and collagen IV in the basement membrane. We demonstrated that two keratinocyte cell lines, one from a neonatal donor and another from an adult diabetic donor, are compatible with this model. We tested this model using an irritation test and showed that the epidermis prevents rapid penetration of sodium dodecyl sulfate. Gene expression analysis revealed differences in keratinocytes obtained from the two donors as well as between 2D (control) and 3D culture conditions. Our human skin model may find potential application for drug and cosmetic testing, disease and wound healing modeling, and aging studies.
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Affiliation(s)
- Maxwell B Nagarajan
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, United States of America
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, United States of America
| | - Alexander J Ainscough
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, United States of America
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, United States of America
| | - Daniel S Reynolds
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, United States of America
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, United States of America
| | - Sebastien G M Uzel
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, United States of America
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, United States of America
| | - Jason W Bjork
- 3M, 3M Center, St. Paul, MN 55144, United States of America
| | - Bryan A Baker
- 3M, 3M Center, St. Paul, MN 55144, United States of America
| | - Amy K McNulty
- 3M, 3M Center, St. Paul, MN 55144, United States of America
| | - Susan L Woulfe
- 3M, 3M Center, St. Paul, MN 55144, United States of America
| | - Jennifer A Lewis
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, United States of America
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, United States of America
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3
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Slyker L, Bonassar LJ. Alginate Conjugation Increases Toughness in Auricular Chondrocyte Seeded Collagen Hydrogels. Bioengineering (Basel) 2023; 10:1037. [PMID: 37760139 PMCID: PMC10526064 DOI: 10.3390/bioengineering10091037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/31/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023] Open
Abstract
Current auricular cartilage replacements for pediatric microtia fail to address the need for long-term integration and neocartilage formation. While collagen hydrogels have been successful in fostering neocartilage formation, the toughness and extensibility of these materials do not match that of native tissue. This study used the N-terminal functionalization of collagen with alginate oligomers to improve toughness and extensibility through metal-ion complexation. Alginate conjugation was confirmed via FTIR spectroscopy. The retention of native collagen fibrillar structure, thermal gelation, and helical conformation in functionalized gels was confirmed via scanning electron microscopy, oscillatory shear rheology, and circular dichroism spectroscopy, respectively. Alginate-calcium complexation enabled a more than two-fold increase in modulus and work density in functionalized collagen with the addition of 50 mM CaCl2, whereas unmodified collagen decreased in both modulus and work density with increasing calcium concentration. Additionally, the extensibility of alginate-functionalized collagen was increased at 25 and 50 mM CaCl2. Following 2-week culture with auricular chondrocytes, alginate-functionalization had no effect on the cytocompatibility of collagen gels, with no effects on cell density, and increased glycosaminoglycan deposition. Custom MATLAB video analysis was then used to quantify fracture toughness, which was more than 5-fold higher following culture in functionalized collagen and almost three-fold higher in unmodified collagen.
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Affiliation(s)
- Leigh Slyker
- Meinig of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Lawrence J. Bonassar
- Meinig of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853, USA
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4
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Fertala J, Wang ML, Rivlin M, Beredjiklian PK, Abboud J, Arnold WV, Fertala A. Extracellular Targets to Reduce Excessive Scarring in Response to Tissue Injury. Biomolecules 2023; 13:biom13050758. [PMID: 37238628 DOI: 10.3390/biom13050758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
Excessive scar formation is a hallmark of localized and systemic fibrotic disorders. Despite extensive studies to define valid anti-fibrotic targets and develop effective therapeutics, progressive fibrosis remains a significant medical problem. Regardless of the injury type or location of wounded tissue, excessive production and accumulation of collagen-rich extracellular matrix is the common denominator of all fibrotic disorders. A long-standing dogma was that anti-fibrotic approaches should focus on overall intracellular processes that drive fibrotic scarring. Because of the poor outcomes of these approaches, scientific efforts now focus on regulating the extracellular components of fibrotic tissues. Crucial extracellular players include cellular receptors of matrix components, macromolecules that form the matrix architecture, auxiliary proteins that facilitate the formation of stiff scar tissue, matricellular proteins, and extracellular vesicles that modulate matrix homeostasis. This review summarizes studies targeting the extracellular aspects of fibrotic tissue synthesis, presents the rationale for these studies, and discusses the progress and limitations of current extracellular approaches to limit fibrotic healing.
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Affiliation(s)
- Jolanta Fertala
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Mark L Wang
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - Michael Rivlin
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - Pedro K Beredjiklian
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - Joseph Abboud
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - William V Arnold
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Rothman Institute of Orthopaedics, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - Andrzej Fertala
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
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5
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Niu C, Xiong Y, Yang L, Xiao X, Yang S, Huang Z, Yang Y, Feng L. Carboxy-terminal telopeptide levels of type I collagen hydrogels modulated the encapsulated cell fate for regenerative medicine. Int J Biol Macromol 2023; 228:826-837. [PMID: 36566813 DOI: 10.1016/j.ijbiomac.2022.12.186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/28/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
The cellular microenvironment has a profound impact on cell proliferation, interaction, and differentiation. In cell encapsulation for disease therapy, type I collagen is an important biomaterial due to its ability to mimic the extracellular matrix. Telopeptides (carboxy-terminal, CTX, and amino-terminal, NTX) protruding from the triple helix structure of type I collagen are cross-link sites, but also mediate the signal transmission in tissue homeostasis. It is worth investigating the features of the hydrogel microenvironment shaped by the tissue-derived type I collagen with various telopeptide levels, which is paramount for encapsulated cell development. Here, we found the fate of encapsulated human adipose-derived stem cells (hADSCs) and human umbilical vein endothelial cells (HUVECs) behaved differently towards decreasing CTX levels in the collagen hydrogels. Even among collagen hydrogels with a small magnitude of CTX variation, similar stiffness and microstructure, the apparent CTX modulation on the proliferation, cell-interaction, and genes expression of encapsulated hADSCs, as well as morphology and tubule structure formation of endothelial cells were observed, suggesting the biological roles of CTX and its modulation on microenvironment for cell development.
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Affiliation(s)
- Chuan Niu
- Department of Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Ying Xiong
- Department of Periodical Press, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Liping Yang
- Department of Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Xiong Xiao
- Department of Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Shaojie Yang
- Department of Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Ziwei Huang
- Department of Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Yuchu Yang
- Department of Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Li Feng
- Department of Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China.
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6
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Yu TH, Yeh TT, Su CY, Yu NY, Chen IC, Fang HW. Preparation and Characterization of Extracellular Matrix Hydrogels Derived from Acellular Cartilage Tissue. J Funct Biomater 2022; 13:jfb13040279. [PMID: 36547539 PMCID: PMC9788521 DOI: 10.3390/jfb13040279] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/04/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022] Open
Abstract
Decellularized matrices can effectively reduce severe immune rejection with their cells and eliminated nucleic acid material and provide specific environments for tissue repair or tissue regeneration. In this study, we prepared acellular cartilage matrix (ACM) powder through the decellularization method and developed ACM hydrogels by physical, chemical, and enzymatic digestion methods. The results demonstrated that the small size group of ACM hydrogels exhibited better gel conditions when the concentration of ACM hydrogels was 30 and 20 mg/mL in 1N HCl through parameter adjustment. The data also confirmed that the ACM hydrogels retained the main components of cartilage: 61.18% of glycosaminoglycan (GAG) and 78.29% of collagen, with 99.61% of its DNA removed compared to samples without the decellularization procedure (set as 100%). Through turbidimetric gelation kinetics, hydrogel rheological property analysis, and hydrogel tissue physical property testing, this study also revealed that increasing hydrogel concentration is helpful for gelation. Besides, the ex vivo test confirmed that a higher concentration of ACM hydrogels had good adhesive properties and could fill in cartilage defects adequately. This study offers useful information for developing and manufacturing ACM hydrogels to serve as potential alternative scaffolds for future cartilage defect treatment.
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Affiliation(s)
- Tsong-Hann Yu
- Department of Orthopedics, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Chenggong Rd., Taipei 114202, Taiwan
| | - Tsu-Te Yeh
- Department of Orthopedics, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Chenggong Rd., Taipei 114202, Taiwan
| | - Chen-Ying Su
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan
| | - Ni-Yin Yu
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan
| | - I-Cheng Chen
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan
- Accelerator for Happiness and Health Industry, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan
- Correspondence: (I.-C.C.); (H.-W.F.); Tel.: +886-2-2771-2171 (ext. 2521) (H.-W.F.)
| | - Hsu-Wei Fang
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan
- Accelerator for Happiness and Health Industry, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, No. 35, Keyan Road, Zhunan 35053, Taiwan
- Correspondence: (I.-C.C.); (H.-W.F.); Tel.: +886-2-2771-2171 (ext. 2521) (H.-W.F.)
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7
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Shen Y, Weitz DA, Forde NR, Shayegan M. Line optical tweezers as controllable micromachines: techniques and emerging trends. SOFT MATTER 2022; 18:5359-5365. [PMID: 35819100 DOI: 10.1039/d2sm00259k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In the past three decades, the technology of optical tweezers has made significant contributions in various scientific areas, including optics, photonics, and nanosciences. Breakthroughs include manipulating particles in both static and dynamic ways, particle sorting, and constructing controllable micromachines. Advances in shaping and controlling the laser beam profile enable control over the position and location of the trap, which has many possible applications. A line optical tweezer (LOT) can be created by rapidly moving a spot optical tweezer using a tool such as a galvanometer mirror or an acousto-optic modulator. By manipulating the intensity profile along the beam line to be asymmetric or non-uniform, the technique can be adapted to various specific applications. Among the many exciting applications of line optical tweezers, in this work, we discuss in detail applications of LOT, including probing colloidal interactions, transporting and sorting of colloidal microspheres, self-propelled motions, trapping anisotropic particles, exploring colloidal interactions at fluid-fluid interfaces, and building optical thermal ratchets. We further discuss prospective applications in each of these areas of soft matter, including polymeric and biological soft materials.
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Affiliation(s)
- Yinan Shen
- Department of Physics, Harvard University, Cambridge, Massachusetts, USA
| | - David A Weitz
- Department of Physics, Harvard University, Cambridge, Massachusetts, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA.
| | - Nancy R Forde
- Department of Physics, Simon Fraser University, Burnaby, BC, Canada
| | - Marjan Shayegan
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA.
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8
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Veettil SP, Gopinath A, Madhan B, Shanmugam G. A cyclodextrin-based macrocyclic oligosaccharide cavitand with a dual functionality limits the collagen fibrillogenesis: A possible carbohydrate-based therapeutic molecule for fibrotic diseases. Int J Biol Macromol 2022; 207:222-231. [PMID: 35259432 DOI: 10.1016/j.ijbiomac.2022.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 02/16/2022] [Accepted: 03/02/2022] [Indexed: 11/05/2022]
Abstract
β-Cyclodextrin (β-CD), a macrocyclic oligosaccharide cavitand, is a well-known candidate for drug delivery and formulation. In this study, we extended the application of β-CD using a β-cyclodextrin sulfate (β-CDS) as a possible therapeutic for fibrotic diseases caused by excess deposition of collagen fibrils. We have strategically chosen β-CDS, which mimics the natural existence of dermatan sulfate in the extracellular matrix, for limiting collagen fibrillation. The hydrophobic nature of the inner core β-CDS is expected to form an inclusion complex with hydrophobic side chain amino acids with the simultaneous action of forming an ionic bond through a negative charge on sulfate group with positively charged amino acids side chain in collagen. Various results suggested that such dual action not only limited the collagen fibrillation but also reduced the fibril size formed in the presence of β-CDS. The contemporary results thus indicate that β-CDS can be explored as a therapeutic molecule in fibrotic diseases.
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Affiliation(s)
- Sruthi Puthan Veettil
- Organic & Bioorganic Chemistry Laboratory, Council of Scientific and Industrial Research (CSIR) - Central Leather Research Institute (CLRI), Adyar, Chennai 600020, India
| | - Arun Gopinath
- CARE Division, CSIR-CLRI, Adyar, Chennai 600020, India
| | | | - Ganesh Shanmugam
- Organic & Bioorganic Chemistry Laboratory, Council of Scientific and Industrial Research (CSIR) - Central Leather Research Institute (CLRI), Adyar, Chennai 600020, India.
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9
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Slyker L, Diamantides N, Kim J, Bonassar LJ. Mechanical performance of collagen gels is dependent on purity, α1/α2 ratio, and telopeptides. J Biomed Mater Res A 2022; 110:11-20. [PMID: 34236763 PMCID: PMC9271356 DOI: 10.1002/jbm.a.37261] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 05/27/2021] [Accepted: 06/25/2021] [Indexed: 01/03/2023]
Abstract
This article describes the compositional, mechanical, and structural differences between collagen gels fabricated from different sources and processing methods. Despite extensive use of collagen in the manufacturing of biomaterials and implants, there is little information as to the variation in properties based on collagen source or processing methods. As such, differences in purity and composition may affect gel structure and mechanical performance. Using mass spectrometry, we assessed protein composition of collagen from seven different sources. The mechanics and gelation kinetics of each gel were assessed through oscillatory shear rheology. Scanning electron microscopy enabled visualization of distinct differences in fiber morphology. Mechanics and gelation kinetics differed with source and processing method and were found to correlate with differences in composition. Gels fabricated from telopeptide-containing collagens had higher storage modulus (144 vs. 54 Pa) and faster gelation (251 vs. 734 s) compared to atelocollagens, despite having lower purity (93.4 vs. 99.8%). For telopeptide-containing collagens, as collagen purity increased, storage modulus increased and fiber diameter decreased. As α1/α2 chain ratio increased, fiber diameter increased and gelation slowed. As such, this study provides an examination of the effects of collagen processing on key quality attributes for use of collagen gels in biomedical contexts.
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Affiliation(s)
- Leigh Slyker
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY
| | | | - Jongkil Kim
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY
| | - Lawrence J. Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY,Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY
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10
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Al-Shaer A, Lyons A, Ishikawa Y, Hudson BG, Boudko SP, Forde NR. Sequence-dependent mechanics of collagen reflect its structural and functional organization. Biophys J 2021; 120:4013-4028. [PMID: 34390685 DOI: 10.1016/j.bpj.2021.08.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 05/25/2021] [Accepted: 08/06/2021] [Indexed: 01/06/2023] Open
Abstract
Extracellular matrix mechanics influence diverse cellular functions, yet surprisingly little is known about the mechanical properties of their constituent collagen proteins. In particular, network-forming collagen IV, an integral component of basement membranes, has been far less studied than fibril-forming collagens. A key feature of collagen IV is the presence of interruptions in the triple-helix-defining (Gly-X-Y) sequence along its collagenous domain. Here, we used atomic force microscopy to determine the impact of sequence heterogeneity on the local flexibility of collagen IV and of the fibril-forming collagen III. Our extracted flexibility profile of collagen IV reveals that it possesses highly heterogeneous mechanics, ranging from semiflexible regions as found for fibril-forming collagens to a lengthy region of high flexibility toward its N-terminus. A simple model in which flexibility is dictated only by the presence of interruptions fit the extracted profile reasonably well, providing insight into the alignment of chains and demonstrating that interruptions, particularly when coinciding in multiple chains, significantly enhance local flexibility. To a lesser extent, sequence variations within the triple helix lead to variable flexibility, as seen along the continuously triple-helical collagen III. We found this fibril-forming collagen to possess a high-flexibility region around its matrix-metalloprotease binding site, suggesting a unique mechanical fingerprint of this region that is key for matrix remodeling. Surprisingly, proline content did not correlate with local flexibility in either collagen type. We also found that physiologically relevant changes in pH and chloride concentration did not alter the flexibility of collagen IV, indicating such environmental changes are unlikely to control its compaction during secretion. Although extracellular chloride ions play a role in triggering collagen IV network formation, they do not appear to modulate the structure of its collagenous domain.
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Affiliation(s)
- Alaa Al-Shaer
- Department of Molecular Biology and Biochemistry, Burnaby, British Columbia, Canada
| | - Aaron Lyons
- Department of Physics, Burnaby, British Columbia, Canada
| | - Yoshihiro Ishikawa
- Department of Ophthalmology, University of California San Francisco, School of Medicine, San Francisco, California
| | - Billy G Hudson
- Department of Medicine, Division of Nephrology and Hypertension, Nashville, Tennessee; Vanderbilt Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, Tennessee; Department of Biochemistry, Nashville, Tennessee; Department of Pathology, Microbiology, and Immunology, Nashville, Tennessee; Department of Cell and Developmental Biology, Nashville, Tennessee; Vanderbilt-Ingram Cancer Center, Nashville, Tennessee; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee
| | - Sergei P Boudko
- Department of Medicine, Division of Nephrology and Hypertension, Nashville, Tennessee; Vanderbilt Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, Tennessee; Department of Biochemistry, Nashville, Tennessee
| | - Nancy R Forde
- Department of Molecular Biology and Biochemistry, Burnaby, British Columbia, Canada; Department of Physics, Burnaby, British Columbia, Canada; Department of Chemistry, Burnaby, British Columbia, Canada; Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, British Columbia, Canada.
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11
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Ahmed A, Joshi IM, Mansouri M, Ahamed NNN, Hsu MC, Gaborski TR, Abhyankar VV. Engineering fiber anisotropy within natural collagen hydrogels. Am J Physiol Cell Physiol 2021; 320:C1112-C1124. [PMID: 33852366 PMCID: PMC8285641 DOI: 10.1152/ajpcell.00036.2021] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 04/06/2021] [Accepted: 04/06/2021] [Indexed: 12/14/2022]
Abstract
It is well known that biophysical properties of the extracellular matrix (ECM), including stiffness, porosity, composition, and fiber alignment (anisotropy), play a crucial role in controlling cell behavior in vivo. Type I collagen (collagen I) is a ubiquitous structural component in the ECM and has become a popular hydrogel material that can be tuned to replicate the mechanical properties found in vivo. In this review article, we describe popular methods to create 2-D and 3-D collagen I hydrogels with anisotropic fiber architectures. We focus on methods that can be readily translated from engineering and materials science laboratories to the life-science community with the overall goal of helping to increase the physiological relevance of cell culture assays.
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Affiliation(s)
- Adeel Ahmed
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, New York
| | - Indranil M Joshi
- Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, New York
| | - Mehran Mansouri
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, New York
| | - Nuzhet N N Ahamed
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, New York
| | - Meng-Chun Hsu
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, New York
| | - Thomas R Gaborski
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, New York
- Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, New York
| | - Vinay V Abhyankar
- Department of Microsystems Engineering, Rochester Institute of Technology, Rochester, New York
- Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, New York
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12
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Sanz-Fraile H, Amoros S, Mendizabal I, Galvez-Monton C, Prat-Vidal C, Bayes-Genis A, Navajas D, Farre R, Otero J. Silk-Reinforced Collagen Hydrogels with Raised Multiscale Stiffness for Mesenchymal Cells 3D Culture. Tissue Eng Part A 2021; 26:358-370. [PMID: 32085691 DOI: 10.1089/ten.tea.2019.0199] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Type I collagen hydrogels are of high interest in tissue engineering. With the evolution of 3D bioprinting technologies, a high number of collagen-based scaffolds have been reported for the development of 3D cell cultures. A recent proposal was to mix collagen with silk fibroin derived from Bombyx mori silkworm. Nevertheless, due to the difficulties in the preparation and the characteristics of the protein, several problems such as phase separation and collagen denaturation appear during the procedure. Therefore, the common solution is to diminish the concentration of collagen although in that way the most biologically relevant component is reduced. In this study, we present a new, simple, and effective method to develop a collagen-silk hybrid hydrogel with high collagen concentration and with increased stiffness approaching that of natural tissues, which could be of high interest for the development of cardiac patches for myocardial regeneration and for preconditioning of mesenchymal stem cells (MSCs) to improve their therapeutic potential. Sericin in the silk was preserved by using a physical solubilizing procedure that results in a preserved fibrous structure of type I collagen, as shown by ultrastructural imaging. The macro- and micromechanical properties of the hybrid hydrogels measured by tensile stretch and atomic force microscopy, respectively, showed a more than twofold stiffening than the collagen-only hydrogels. Rheological measurements showed improved printability properties for the developed biomaterial. The suitability of the hydrogels for 3D cell culture was assessed by 3D bioprinting bone marrow-derived MSCs cultured within the scaffolds. The result was a biomaterial with improved printability characteristics that better resembled the mechanical properties of natural soft tissues while preserving biocompatibility owing to the high concentration of collagen. Impact statement In this study, we report the development of silk microfiber-reinforced type I collagen hydrogels for 3D bioprinting and cell culture. In contrast with previously reported studies, a novel physical method allowed the preservation of the silk sericin protein. Hydrogels were stable, showed no phase separation between the biomaterials, and they presented improved printability. An increase between two- and threefold of the multiscale stiffness of the scaffolds was achieved with no need of using additional crosslinkers or complex methods, which could be of high relevance for cardiac patches development and for preconditioning mesenchymal stem cells (MSCs) for therapeutic applications. We demonstrate that bone marrow-derived MSCs can be effectively bioprinted and 3D cultured within the stiffened structures.
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Affiliation(s)
- Hector Sanz-Fraile
- Unit of Biophysics and Bioengineering, School of Medicine and Health Sciences, Universitat de Barcelona, Barcelona, Spain
| | - Susana Amoros
- ICREC Research Program, Germans Trias i Pujol Health Science Research Institute, Badalona, Spain
| | - Irene Mendizabal
- Unit of Biophysics and Bioengineering, School of Medicine and Health Sciences, Universitat de Barcelona, Barcelona, Spain
| | - Carolina Galvez-Monton
- ICREC Research Program, Germans Trias i Pujol Health Science Research Institute, Badalona, Spain.,Hearth Institute (iCor), Germans Trias i Pujol University Hospital, Badalona, Spain.,CIBER Cardiovascular, Instituto de Salud Carlos III, Madrid, Spain
| | - Cristina Prat-Vidal
- ICREC Research Program, Germans Trias i Pujol Health Science Research Institute, Badalona, Spain.,Hearth Institute (iCor), Germans Trias i Pujol University Hospital, Badalona, Spain.,CIBER Cardiovascular, Instituto de Salud Carlos III, Madrid, Spain.,Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Antoni Bayes-Genis
- ICREC Research Program, Germans Trias i Pujol Health Science Research Institute, Badalona, Spain.,Hearth Institute (iCor), Germans Trias i Pujol University Hospital, Badalona, Spain.,CIBER Cardiovascular, Instituto de Salud Carlos III, Madrid, Spain.,Department of Medicine, Autonomous University of Barcelona, Barcelona, Spain
| | - Daniel Navajas
- Unit of Biophysics and Bioengineering, School of Medicine and Health Sciences, Universitat de Barcelona, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.,Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Ramon Farre
- Unit of Biophysics and Bioengineering, School of Medicine and Health Sciences, Universitat de Barcelona, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.,Institut d'investigacions Biomèdiques Agustí Pi i Sunyer, Barcelona, Spain
| | - Jorge Otero
- Unit of Biophysics and Bioengineering, School of Medicine and Health Sciences, Universitat de Barcelona, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
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13
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Wei F, Liu S, Chen M, Tian G, Zha K, Yang Z, Jiang S, Li M, Sui X, Chen Z, Guo Q. Host Response to Biomaterials for Cartilage Tissue Engineering: Key to Remodeling. Front Bioeng Biotechnol 2021; 9:664592. [PMID: 34017827 PMCID: PMC8129172 DOI: 10.3389/fbioe.2021.664592] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/14/2021] [Indexed: 12/18/2022] Open
Abstract
Biomaterials play a core role in cartilage repair and regeneration. The success or failure of an implanted biomaterial is largely dependent on host response following implantation. Host response has been considered to be influenced by numerous factors, such as immune components of materials, cytokines and inflammatory agents induced by implants. Both synthetic and native materials involve immune components, which are also termed as immunogenicity. Generally, the innate and adaptive immune system will be activated and various cytokines and inflammatory agents will be consequently released after biomaterials implantation, and further triggers host response to biomaterials. This will guide the constructive remolding process of damaged tissue. Therefore, biomaterial immunogenicity should be given more attention. Further understanding the specific biological mechanisms of host response to biomaterials and the effects of the host-biomaterial interaction may be beneficial to promote cartilage repair and regeneration. In this review, we summarized the characteristics of the host response to implants and the immunomodulatory properties of varied biomaterial. We hope this review will provide scientists with inspiration in cartilage regeneration by controlling immune components of biomaterials and modulating the immune system.
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Affiliation(s)
- Fu Wei
- Beijing Key Lab of Regenerative Medicine in Orthopedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Institute of Orthopedics, Chinese PLA General Hospital, Beijing, China.,Department of Orthopedics, The First Affiliated Hospital of University of South China, Hengyang, China
| | - Shuyun Liu
- Beijing Key Lab of Regenerative Medicine in Orthopedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Institute of Orthopedics, Chinese PLA General Hospital, Beijing, China
| | - Mingxue Chen
- Department of Orthopedic Surgery, Beijing Jishuitan Hospital, Fourth Clinical College of Peking University, Beijing, China
| | - Guangzhao Tian
- Beijing Key Lab of Regenerative Medicine in Orthopedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Institute of Orthopedics, Chinese PLA General Hospital, Beijing, China.,School of Medicine, Nankai University, Tianjin, China
| | - Kangkang Zha
- Beijing Key Lab of Regenerative Medicine in Orthopedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Institute of Orthopedics, Chinese PLA General Hospital, Beijing, China.,School of Medicine, Nankai University, Tianjin, China
| | - Zhen Yang
- Beijing Key Lab of Regenerative Medicine in Orthopedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Institute of Orthopedics, Chinese PLA General Hospital, Beijing, China.,School of Medicine, Nankai University, Tianjin, China
| | | | - Muzhe Li
- Department of Orthopedics, The First Affiliated Hospital of University of South China, Hengyang, China
| | - Xiang Sui
- Beijing Key Lab of Regenerative Medicine in Orthopedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Institute of Orthopedics, Chinese PLA General Hospital, Beijing, China
| | - Zhiwei Chen
- Department of Orthopedics, The First Affiliated Hospital of University of South China, Hengyang, China
| | - Quanyi Guo
- Beijing Key Lab of Regenerative Medicine in Orthopedics, Key Laboratory of Musculoskeletal Trauma and War Injuries, PLA, Institute of Orthopedics, Chinese PLA General Hospital, Beijing, China
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14
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Brain organoid formation on decellularized porcine brain ECM hydrogels. PLoS One 2021; 16:e0245685. [PMID: 33507989 PMCID: PMC7842896 DOI: 10.1371/journal.pone.0245685] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 01/05/2021] [Indexed: 12/21/2022] Open
Abstract
Human brain tissue models such as cerebral organoids are essential tools for developmental and biomedical research. Current methods to generate cerebral organoids often utilize Matrigel as an external scaffold to provide structure and biologically relevant signals. Matrigel however is a nonspecific hydrogel of mouse tumor origin and does not represent the complexity of the brain protein environment. In this study, we investigated the application of a decellularized adult porcine brain extracellular matrix (B-ECM) which could be processed into a hydrogel (B-ECM hydrogel) to be used as a scaffold for human embryonic stem cell (hESC)-derived brain organoids. We decellularized pig brains with a novel detergent- and enzyme-based method and analyzed the biomaterial properties, including protein composition and content, DNA content, mechanical characteristics, surface structure, and antigen presence. Then, we compared the growth of human brain organoid models with the B-ECM hydrogel or Matrigel controls in vitro. We found that the native brain source material was successfully decellularized with little remaining DNA content, while Mass Spectrometry (MS) showed the loss of several brain-specific proteins, while mainly different collagen types remained in the B-ECM. Rheological results revealed stable hydrogel formation, starting from B-ECM hydrogel concentrations of 5 mg/mL. hESCs cultured in B-ECM hydrogels showed gene expression and differentiation outcomes similar to those grown in Matrigel. These results indicate that B-ECM hydrogels can be used as an alternative scaffold for human cerebral organoid formation, and may be further optimized for improved organoid growth by further improving protein retention other than collagen after decellularization.
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15
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Sun B, Li C, Mao Y, Qiao Z, Jia R, Huang T, Xu D, Yang W. Distinctive characteristics of collagen and gelatin extracted from
Dosidicus gigas
skin. Int J Food Sci Technol 2021. [DOI: 10.1111/ijfs.14968] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bolun Sun
- College of Food and Pharmaceutical Sciences Ningbo University Ningbo315211China
| | - Chao Li
- College of Food and Pharmaceutical Sciences Ningbo University Ningbo315211China
- Key Laboratory of Animal Protein Food Deep Processing Technology of Zhejiang Province Ningbo University Ningbo315211China
| | - Yuhong Mao
- College of Biological Science and Engineering Fuzhou University Fuzhou350108China
| | - Zhaohui Qiao
- College of Food and Pharmaceutical Sciences Ningbo University Ningbo315211China
- Key Laboratory of Animal Protein Food Deep Processing Technology of Zhejiang Province Ningbo University Ningbo315211China
| | - Ru Jia
- College of Food and Pharmaceutical Sciences Ningbo University Ningbo315211China
- Key Laboratory of Animal Protein Food Deep Processing Technology of Zhejiang Province Ningbo University Ningbo315211China
| | - Tao Huang
- College of Food and Pharmaceutical Sciences Ningbo University Ningbo315211China
- Key Laboratory of Animal Protein Food Deep Processing Technology of Zhejiang Province Ningbo University Ningbo315211China
| | - Dalun Xu
- College of Food and Pharmaceutical Sciences Ningbo University Ningbo315211China
- Key Laboratory of Animal Protein Food Deep Processing Technology of Zhejiang Province Ningbo University Ningbo315211China
| | - Wenge Yang
- College of Food and Pharmaceutical Sciences Ningbo University Ningbo315211China
- Key Laboratory of Animal Protein Food Deep Processing Technology of Zhejiang Province Ningbo University Ningbo315211China
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16
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Collagen Structure-Function Mapping Informs Applications for Regenerative Medicine. Bioengineering (Basel) 2020; 8:bioengineering8010003. [PMID: 33383610 PMCID: PMC7824244 DOI: 10.3390/bioengineering8010003] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/21/2022] Open
Abstract
Type I collagen, the predominant protein of vertebrates, assembles into fibrils that orchestrate the form and function of bone, tendon, skin, and other tissues. Collagen plays roles in hemostasis, wound healing, angiogenesis, and biomineralization, and its dysfunction contributes to fibrosis, atherosclerosis, cancer metastasis, and brittle bone disease. To elucidate the type I collagen structure-function relationship, we constructed a type I collagen fibril interactome, including its functional sites and disease-associated mutations. When projected onto an X-ray diffraction model of the native collagen microfibril, data revealed a matrix interaction domain that assumes structural roles including collagen assembly, crosslinking, proteoglycan (PG) binding, and mineralization, and the cell interaction domain supporting dynamic aspects of collagen biology such as hemostasis, tissue remodeling, and cell adhesion. Our type III collagen interactome corroborates this model. We propose that in quiescent tissues, the fibril projects a structural face; however, tissue injury releases blood into the collagenous stroma, triggering exposure of the fibrils' cell and ligand binding sites crucial for tissue remodeling and regeneration. Applications of our research include discovery of anti-fibrotic antibodies and elucidating their interactions with collagen, and using insights from our angiogenesis studies and collagen structure-function model to inform the design of super-angiogenic collagens and collagen mimetics.
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17
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Fertala A. Three Decades of Research on Recombinant Collagens: Reinventing the Wheel or Developing New Biomedical Products? Bioengineering (Basel) 2020; 7:E155. [PMID: 33276472 PMCID: PMC7712652 DOI: 10.3390/bioengineering7040155] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/16/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023] Open
Abstract
Collagens provide the building blocks for diverse tissues and organs. Furthermore, these proteins act as signaling molecules that control cell behavior during organ development, growth, and repair. Their long half-life, mechanical strength, ability to assemble into fibrils and networks, biocompatibility, and abundance from readily available discarded animal tissues make collagens an attractive material in biomedicine, drug and food industries, and cosmetic products. About three decades ago, pioneering experiments led to recombinant human collagens' expression, thereby initiating studies on the potential use of these proteins as substitutes for the animal-derived collagens. Since then, scientists have utilized various systems to produce native-like recombinant collagens and their fragments. They also tested these collagens as materials to repair tissues, deliver drugs, and serve as therapeutics. Although many tests demonstrated that recombinant collagens perform as well as their native counterparts, the recombinant collagen technology has not yet been adopted by the biomedical, pharmaceutical, or food industry. This paper highlights recent technologies to produce and utilize recombinant collagens, and it contemplates their prospects and limitations.
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Affiliation(s)
- Andrzej Fertala
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Curtis Building, Room 501, 1015 Walnut Street, Philadelphia, PA 19107, USA
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18
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Morimoto K, Kunii S, Tonomura B. Defective chicken skin collagen molecules, hydrolyzed by actinidain protease, assemble to form loosely packed fibrils that promote cell spheroid formation. Int J Biol Macromol 2020; 167:1066-1075. [PMID: 33220378 DOI: 10.1016/j.ijbiomac.2020.11.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/25/2020] [Accepted: 11/08/2020] [Indexed: 11/30/2022]
Abstract
Cells recognize collagen fibrils as the first step in the process of adherence. Fibrils of chicken skin actinidain-hydrolyzed collagen (low adhesive scaffold collagen, LASCol), in which the telopeptide domains are almost completely removed, cause adhering cells to form spheroids instead of adopting a monolayer morphology. Our goal was to elucidate the ultrastructure of the LASCol fibrils compared with pepsin-hydrolyzed collagen (PepCol) fibrils. At low concentration of 0.2 mg/mL, the time to reach the maximum increasing rate of turbidity for LASCol was all slower than that for PepCol. Differential scanning calorimetry showed that the thermal stability of collagen self-assembly changed significantly between pH 5.5 and pH 6.6 with and without a small number of telopeptides. However, the calorimetric enthalpy change did not vary much in that pH range. The melting temperature of LASCol fibrils at pH 7.3 was 55.1 °C, whereas PepCol fibrils exhibited a peak around 56.9 °C. The D-periodicity of each fibril was the same at 67 nm. Nevertheless, the looseness of molecular packing in LASCol fibrils was demonstrated by circular dichroism measurements and immuno-scanning electron microscopy with a polyclonal antibody against type I collagen. As there is a close relationship between function and structure, loosely packed collagen fibrils would be one factor that promotes cell spheroid formation.
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Affiliation(s)
- Koichi Morimoto
- Department of Genetic Engineering, Kindai University, 930 Nishimitani, Kinokawa, Wakayama 649-6493, Japan.
| | - Saori Kunii
- Department of Genetic Engineering, Kindai University, 930 Nishimitani, Kinokawa, Wakayama 649-6493, Japan
| | - Ben'ichiro Tonomura
- Department of Genetic Engineering, Kindai University, 930 Nishimitani, Kinokawa, Wakayama 649-6493, Japan
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19
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Distinct effects of different matrix proteoglycans on collagen fibrillogenesis and cell-mediated collagen reorganization. Sci Rep 2020; 10:19065. [PMID: 33149218 PMCID: PMC7642422 DOI: 10.1038/s41598-020-76107-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 10/22/2020] [Indexed: 01/19/2023] Open
Abstract
The extracellular matrix (ECM) is a complex mixture composed of fibrillar collagens as well as additional protein and carbohydrate components. Proteoglycans (PGs) contribute to the heterogeneity of the ECM and play an important role in its structure and function. While the small leucine rich proteoglycans (SLRPs), including decorin and lumican, have been studied extensively as mediators of collagen fibrillogenesis and organization, the function of large matrix PGs in collagen matrices is less well known. In this study, we showed that different matrix PGs have distinct roles in regulating collagen behaviors. We found that versican, a large chondroitin sulfate PG, promotes collagen fibrillogenesis in a turbidity assay and upregulates cell-mediated collagen compaction and reorganization, whereas aggrecan, a structurally-similar large PG, has different and often opposing effects on collagen. Compared to versican, decorin and lumican also have distinct functions in regulating collagen behaviors. The different ways in which matrix PGs interact with collagen have important implications for understanding the role of the ECM in diseases such as fibrosis and cancer, and suggest that matrix PGs are potential therapeutic targets.
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20
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Type II Collagen from Cartilage of Acipenser baerii Promotes Wound Healing in Human Dermal Fibroblasts and in Mouse Skin. Mar Drugs 2020; 18:md18100511. [PMID: 33050593 PMCID: PMC7601416 DOI: 10.3390/md18100511] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/23/2020] [Accepted: 10/07/2020] [Indexed: 12/21/2022] Open
Abstract
Type II collagen is an important component of cartilage; however, little is known about its effect on skin wound healing. In this study, type II collagen was extracted from the cartilage of Acipenser baerii and its effect on in vitro and in vivo wound healing was compared to type I collagen derived from tilapia skin. Sturgeon cartilage collagen (SCC) was composed of α1 chains and with a thermal denaturation (Td) at 22.5 and melting temperature (Tm) at 72.5 °C. Coating SCC potentiated proliferation, migration, and invasion of human dermal fibroblast adult (HDFa) cells. Furthermore, SCC upregulated the gene expression of extracellular matrix (ECM) components (col Iα1, col IIIα1, elastin, and Has2) and epithelial-mesenchymal transition (EMT) molecules (N-cadherin, Snail, and MMP-1) in HDFa. Pretreatment with Akt and mitogen-activated protein kinase (MAPK) inhibitors significantly attenuated the HDFa invasion caused by SCC. In mice, the application of SCC on dorsal wounds effectively facilitated wound healing as evidenced by 40–59% wound contraction, whereas the untreated wounds were 18%. We observed that SCC reduced inflammation, promoted granulation, tissue formation, and ECM deposition, as well as re-epithelialization in skin wounds. In addition, SCC markedly upregulated the production of growth factors in the dermis, and dermal and subcutaneous white adipose tissue; in contrast, the administration of tilapia skin collagen (TSC) characterized by typical type I collagen was mainly expressed in the epidermis. Collectively, these findings indicate SCC accelerated wound healing by targeting fibroblast in vitro and in vivo.
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21
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Lehmann K, Shayegan M, Blab GA, Forde NR. Optical Tweezers Approaches for Probing Multiscale Protein Mechanics and Assembly. Front Mol Biosci 2020; 7:577314. [PMID: 33134316 PMCID: PMC7573139 DOI: 10.3389/fmolb.2020.577314] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/27/2020] [Indexed: 01/09/2023] Open
Abstract
Multi-step assembly of individual protein building blocks is key to the formation of essential higher-order structures inside and outside of cells. Optical tweezers is a technique well suited to investigate the mechanics and dynamics of these structures at a variety of size scales. In this mini-review, we highlight experiments that have used optical tweezers to investigate protein assembly and mechanics, with a focus on the extracellular matrix protein collagen. These examples demonstrate how optical tweezers can be used to study mechanics across length scales, ranging from the single-molecule level to fibrils to protein networks. We discuss challenges in experimental design and interpretation, opportunities for integration with other experimental modalities, and applications of optical tweezers to current questions in protein mechanics and assembly.
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Affiliation(s)
- Kathrin Lehmann
- Department of Physics, Simon Fraser University, Burnaby, BC, Canada.,Soft Condensed Matter and Biophysics, Utrecht University, Utrecht, Netherlands
| | - Marjan Shayegan
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States
| | - Gerhard A Blab
- Soft Condensed Matter and Biophysics, Utrecht University, Utrecht, Netherlands
| | - Nancy R Forde
- Department of Physics, Simon Fraser University, Burnaby, BC, Canada.,Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada.,Centre for Cell Biology, Development and Disease (C2D2), Simon Fraser University, Burnaby, BC, Canada
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22
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Burla F, Dussi S, Martinez-Torres C, Tauber J, van der Gucht J, Koenderink GH. Connectivity and plasticity determine collagen network fracture. Proc Natl Acad Sci U S A 2020; 117:8326-8334. [PMID: 32238564 PMCID: PMC7165426 DOI: 10.1073/pnas.1920062117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Collagen forms the structural scaffold of connective tissues in all mammals. Tissues are remarkably resistant against mechanical deformations because collagen molecules hierarchically self-assemble in fibrous networks that stiffen with increasing strain. Nevertheless, collagen networks do fracture when tissues are overloaded or subject to pathological conditions such as aneurysms. Prior studies of the role of collagen in tissue fracture have mainly focused on tendons, which contain highly aligned bundles of collagen. By contrast, little is known about fracture of the orientationally more disordered collagen networks present in many other tissues such as skin and cartilage. Here, we combine shear rheology of reconstituted collagen networks with computer simulations to investigate the primary determinants of fracture in disordered collagen networks. We show that the fracture strain is controlled by the coordination number of the network junctions, with less connected networks fracturing at larger strains. The hierarchical structure of collagen fine-tunes the fracture strain by providing structural plasticity at the network and fiber level. Our findings imply that low connectivity and plasticity provide protective mechanisms against network fracture that can optimize the strength of biological tissues.
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Affiliation(s)
- Federica Burla
- Biological Soft Matter Group, Department of Living Matter, AMOLF, 1098 XG Amsterdam, The Netherlands
| | - Simone Dussi
- Physical Chemistry and Soft Matter, Wageningen University and Research, 6708 WE Wageningen, The Netherlands
| | - Cristina Martinez-Torres
- Biological Soft Matter Group, Department of Living Matter, AMOLF, 1098 XG Amsterdam, The Netherlands
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Justin Tauber
- Physical Chemistry and Soft Matter, Wageningen University and Research, 6708 WE Wageningen, The Netherlands
| | - Jasper van der Gucht
- Physical Chemistry and Soft Matter, Wageningen University and Research, 6708 WE Wageningen, The Netherlands;
| | - Gijsje H Koenderink
- Biological Soft Matter Group, Department of Living Matter, AMOLF, 1098 XG Amsterdam, The Netherlands;
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
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23
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Burla F, Sentjabrskaja T, Pletikapic G, van Beugen J, Koenderink GH. Particle diffusion in extracellular hydrogels. SOFT MATTER 2020; 16:1366-1376. [PMID: 31939987 DOI: 10.1039/c9sm01837a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Hyaluronic acid is an abundant polyelectrolyte in the human body that forms extracellular hydrogels in connective tissues. It is essential for regulating tissue biomechanics and cell-cell communication, yet hyaluronan overexpression is associated with pathological situations such as cancer and multiple sclerosis. Due to its enormous molecular weight (in the range of millions of Daltons), accumulation of hyaluronan hinders transport of macromolecules including nutrients and growth factors through tissues and also hampers drug delivery. However, the exact contribution of hyaluronan to tissue penetrability is poorly understood due to the complex structure and molecular composition of tissues. Here we reconstitute biomimetic hyaluronan gels and systematically investigate the effects of gel composition and crosslinking on the diffusion of microscopic tracer particles. We combine ensemble-averaged measurements via differential dynamic microscopy with single-particle tracking. We show that the particle diffusivity depends on the particle size relative to the network pore size and also on the stress relaxation dynamics of the network. We furthermore show that addition of collagen, the other major biopolymer in tissues, causes the emergence of caged particle dynamics. Our findings are useful for understanding macromolecular transport in tissues and for designing biomimetic extracellular matrix hydrogels for drug delivery and tissue regeneration.
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Affiliation(s)
- Federica Burla
- AMOLF, Department of Living Matter, Biological Soft Matter group, Science Park 104, 1098 XG Amsterdam, The Netherlands
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24
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Kirkness MWH, Lehmann K, Forde NR. Mechanics and structural stability of the collagen triple helix. Curr Opin Chem Biol 2019; 53:98-105. [DOI: 10.1016/j.cbpa.2019.08.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 07/24/2019] [Accepted: 08/12/2019] [Indexed: 01/18/2023]
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25
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Ban E, Wang H, Franklin JM, Liphardt JT, Janmey PA, Shenoy VB. Strong triaxial coupling and anomalous Poisson effect in collagen networks. Proc Natl Acad Sci U S A 2019; 116:6790-6799. [PMID: 30894480 PMCID: PMC6452734 DOI: 10.1073/pnas.1815659116] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
While cells within tissues generate and sense 3D states of strain, the current understanding of the mechanics of fibrous extracellular matrices (ECMs) stems mainly from uniaxial, biaxial, and shear tests. Here, we demonstrate that the multiaxial deformations of fiber networks in 3D cannot be inferred solely based on these tests. The interdependence of the three principal strains gives rise to anomalous ratios of biaxial to uniaxial stiffness between 8 and 9 and apparent Poisson's ratios larger than 1. These observations are explained using a microstructural network model and a coarse-grained constitutive framework that predicts the network Poisson effect and stress-strain responses in uniaxial, biaxial, and triaxial modes of deformation as a function of the microstructural properties of the network, including fiber mechanics and pore size of the network. Using this theoretical approach, we found that accounting for the Poisson effect leads to a 100-fold increase in the perceived elastic stiffness of thin collagen samples in extension tests, reconciling the seemingly disparate measurements of the stiffness of collagen networks using different methods. We applied our framework to study the formation of fiber tracts induced by cellular forces. In vitro experiments with low-density networks showed that the anomalous Poisson effect facilitates higher densification of fibrous tracts, associated with the invasion of cancerous acinar cells. The approach developed here can be used to model the evolving mechanics of ECM during cancer invasion and fibrosis.
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Affiliation(s)
- Ehsan Ban
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA 19104
- Department of Materials Science and Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104
| | - Hailong Wang
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA 19104
- Department of Materials Science and Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104
- Department of Modern Mechanics, Chinese Academy of Sciences Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - J Matthew Franklin
- Department of Bioengineering, Stanford University, Stanford, CA 94305
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305
| | - Jan T Liphardt
- Department of Bioengineering, Stanford University, Stanford, CA 94305
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305
| | - Paul A Janmey
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA 19104
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104
| | - Vivek B Shenoy
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA 19104;
- Department of Materials Science and Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104
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Serna JA, Florez SL, Talero VA, Briceño JC, Muñoz-Camargo C, Cruz JC. Formulation and Characterization of a SIS-Based Photocrosslinkable Bioink. Polymers (Basel) 2019; 11:polym11030569. [PMID: 30960553 PMCID: PMC6473614 DOI: 10.3390/polym11030569] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/05/2019] [Accepted: 03/13/2019] [Indexed: 01/16/2023] Open
Abstract
Decellularized extracellular matrices (dECMs) represent a promising alternative as a source of materials to develop scaffolds that closely mimic the native environment of cells. As a result, dECMs have attracted significant attention for their applications in regenerative medicine and tissue engineering. One such application is 3D bioprinting, in which dECMs can be used to prepare bioinks with the biomimicry attributes required for regeneration purposes. Formulating bioinks is, however, challenging, due to difficulties in assuring that the printed materials match the mechanical properties of the tissue which is to be regenerated. To tackle this issue, a number of strategies have been devised, including crosslinking methods, the addition of synthetic materials as excipients, and the use of synthetic matrices for casting. We are particularly interested in extrusion-based 3D bioprinting, mainly due to the ease of rapidly conducting tests for adjusting operating conditions such that the required rheological and mechanical properties are met when using it. Here, we propose a novel bioink that consists of an acid-based precipitation of a small intestinal submucosa (SIS) dECM. The formulated bioink also relies on photocrosslinking reactions to attempt to control gelation and ultimately the mechanical properties of the extruded material. Photoinitiation was explored with the aid of varying concentrations of riboflavin (RF). Manual extrusion and rheological flow tests confirmed the printability and shear-thinning behavior of all formulations. Photocrosslinking reactions, however, failed to promote a substantial increase in gelation, which was attributed to considerable entanglement of undigested collagen molecules. As a result, pendant amine groups thought to be involved in the photo-mediated reactions remain largely inaccessible. In silico computational fluid dynamics (CFD) simulations were implemented to determine shear stress values on the bioink along the exit of the printing nozzle. Moreover, we calculated a stability parameter as a means to estimate changes in the bioink stability during the extrusion process. Future studies should be directed toward assessing the role of temperature-induced gelation in the rheological properties of the bioink and the development of strategies to improve the efficiency of photocrosslinking processes.
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Affiliation(s)
- Julian A Serna
- Department of Biomedical Engineering, School of Engineering, Universidad de los Andes, Carrera 1 No. 18A-12, 111711 Bogotá, Colombia.
| | - Sergio Leonardo Florez
- Department of Electrical and Electronics Engineering, School of Engineering, Universidad de los Andes, Carrera 1 No. 18A-12, 111711 Bogotá, Colombia.
| | - Vivian A Talero
- Department of Biomedical Engineering, School of Engineering, Universidad de los Andes, Carrera 1 No. 18A-12, 111711 Bogotá, Colombia.
| | - Juan C Briceño
- Department of Biomedical Engineering, School of Engineering, Universidad de los Andes, Carrera 1 No. 18A-12, 111711 Bogotá, Colombia.
| | - Carolina Muñoz-Camargo
- Department of Biomedical Engineering, School of Engineering, Universidad de los Andes, Carrera 1 No. 18A-12, 111711 Bogotá, Colombia.
| | - Juan C Cruz
- Department of Biomedical Engineering, School of Engineering, Universidad de los Andes, Carrera 1 No. 18A-12, 111711 Bogotá, Colombia.
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Kirkness MWH, Forde NR. Single-Molecule Assay for Proteolytic Susceptibility: Force-Induced Collagen Destabilization. Biophys J 2019; 114:570-576. [PMID: 29414702 DOI: 10.1016/j.bpj.2017.12.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 12/01/2017] [Accepted: 12/11/2017] [Indexed: 01/07/2023] Open
Abstract
Force plays a key role in regulating dynamics of biomolecular structure and interactions, yet techniques are lacking to manipulate and continuously read out this response with high throughput. We present an enzymatic assay for force-dependent accessibility of structure that makes use of a wireless mini-radio centrifuge force microscope to provide a real-time readout of kinetics. The microscope is designed for ease of use, fits in a standard centrifuge bucket, and offers high-throughput, video-rate readout of individual proteolytic cleavage events. Proteolysis measurements on thousands of tethered collagen molecules show a load-enhanced trypsin sensitivity, indicating destabilization of the triple helix.
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Affiliation(s)
- Michael W H Kirkness
- Department of Molecular Biology and Biochemistry, Burnaby, British Columbia, Canada
| | - Nancy R Forde
- Department of Molecular Biology and Biochemistry, Burnaby, British Columbia, Canada; Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada.
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Clustering, Spatial Distribution, and Phosphorylation of Discoidin Domain Receptors 1 and 2 in Response to Soluble Collagen I. J Mol Biol 2018; 431:368-390. [PMID: 30458172 DOI: 10.1016/j.jmb.2018.11.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 11/06/2018] [Accepted: 11/14/2018] [Indexed: 12/24/2022]
Abstract
Discoidin domain receptors (DDR1 and DDR2) are receptor tyrosine kinases that signal in response to collagen. We had previously shown that collagen binding leads to clustering of DDR1b, a process partly mediated by its extracellular domain (ECD). In this study, we investigated (i) the impact of the oligomeric state of DDR2 ECD on collagen binding and fibrillogenesis, (ii) the effect of collagen binding on DDR2 clustering, and (iii) the spatial distribution and phosphorylation status of DDR1b and DDR2 after collagen stimulation. Studies were conducted using purified recombinant DDR2 ECD proteins in monomeric, dimeric or oligomeric state, and MC3T3-E1 cells expressing full-length DDR2-GFP or DDR1b-YFP. We show that the oligomeric form of DDR2 ECD displayed enhanced binding to collagen and inhibition of fibrillogenesis. Using atomic force and fluorescence microscopy, we demonstrate that unlike DDR1b, DDR2 ECD and DDR2-GFP do not undergo collagen-induced receptor clustering. However, after prolonged collagen stimulation, both DDR1b-YFP and DDR2-GFP formed filamentous structures consistent with spatial re-distribution of DDRs in cells. Immunocytochemistry revealed that while DDR1b clusters co-localized with non-fibrillar collagen, DDR1b/DDR2 filamentous structures associated with collagen fibrils. Antibodies against a tyrosine phosphorylation site in the intracellular juxtamembrane region of DDR1b displayed positive signals in both DDR1b clusters and filamentous structures. However, only the filamentous structures of both DDR1b and DDR2 co-localized with antibodies directed against tyrosine phosphorylation sites within the receptor kinase domain. Our results uncover key differences and similarities in the clustering abilities and spatial distribution of DDR1b and DDR2 and their impact on receptor phosphorylation.
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Rezaei N, Lyons A, Forde NR. Environmentally Controlled Curvature of Single Collagen Proteins. Biophys J 2018; 115:1457-1469. [PMID: 30269884 DOI: 10.1016/j.bpj.2018.09.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/02/2018] [Accepted: 09/04/2018] [Indexed: 12/01/2022] Open
Abstract
The predominant structural protein in vertebrates is collagen, which plays a key role in extracellular matrix and connective tissue mechanics. Despite its prevalence and physical importance in biology, the mechanical properties of molecular collagen are far from established. The flexibility of its triple helix is unresolved, with descriptions from different experimental techniques ranging from flexible to semirigid. Furthermore, it is unknown how collagen type (homo- versus heterotrimeric) and source (tissue derived versus recombinant) influence flexibility. Using SmarTrace, a chain-tracing algorithm we devised, we performed statistical analysis of collagen conformations collected with atomic force microscopy to determine the protein's mechanical properties. Our results show that types I, II, and III collagens-the key fibrillar varieties-exhibit similar molecular flexibilities. However, collagen conformations are strongly modulated by salt, transitioning from compact to extended as KCl concentration increases in both neutral and acidic pH. Although analysis with a standard worm-like chain model suggests that the persistence length of collagen can attain a wide range of values within the literature range, closer inspection reveals that this modulation of collagen's conformational behavior is not due to changes in flexibility but rather arises from the induction of curvature (either intrinsic or induced by interactions with the mica surface). By modifying standard polymer theory to include innate curvature, we show that collagen behaves as an equilibrated curved worm-like chain in two dimensions. Analysis within the curved worm-like chain model shows that collagen's curvature depends strongly on pH and salt, whereas its persistence length does not. Thus, we find that triple-helical collagen is well described as semiflexible irrespective of source, type, pH, and salt environment. These results demonstrate that collagen is more flexible than its conventional description as a rigid rod, which may have implications for its cellular processing and secretion.
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Affiliation(s)
- Nagmeh Rezaei
- Department of Physics, Simon Fraser University, Burnaby, Canada
| | - Aaron Lyons
- Department of Physics, Simon Fraser University, Burnaby, Canada
| | - Nancy R Forde
- Department of Physics, Simon Fraser University, Burnaby, Canada.
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30
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Loosemore VE, Forde NR. Effects of finite and discrete sampling and blur on microrheology experiments. OPTICS EXPRESS 2017; 25:31239-31252. [PMID: 29245801 DOI: 10.1364/oe.25.031239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 10/28/2017] [Indexed: 06/07/2023]
Abstract
The frequency-dependent viscous and elastic properties of fluids can be determined from measurements of the thermal fluctuations of a micron-sized particle trapped by optical tweezers. Finite bandwidth and other instrument limitations lead to systematic errors in measurement of the fluctuations. In this work, we numerically represented power spectra of bead position measurements as if collected by two different measurement devices: a quadrant photodiode, which measures the deflection of the trapping laser; and a high-speed camera, which images the trapped bead directly. We explored the effects of aliasing, camera blur, sampling frequency, and measurement time. By comparing the power spectrum, complex response function, and the complex shear modulus with the ideal values, we found that the viscous and elastic properties inferred from the data are affected by the instrument limitations of each device. We discuss how these systematic effects might affect experimental results from microrheology measurements and suggest approaches to reduce discrepancies.
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