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Casanova EA, Rodriguez-Palomo A, Stähli L, Arnke K, Gröninger O, Generali M, Neldner Y, Tiziani S, Dominguez AP, Guizar-Sicairos M, Gao Z, Appel C, Nielsen LC, Georgiadis M, Weber FE, Stark W, Pape HC, Cinelli P, Liebi M. SAXS imaging reveals optimized osseointegration properties of bioengineered oriented 3D-PLGA/aCaP scaffolds in a critical size bone defect model. Biomaterials 2023; 294:121989. [PMID: 36628888 DOI: 10.1016/j.biomaterials.2022.121989] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 12/01/2022] [Accepted: 12/24/2022] [Indexed: 01/03/2023]
Abstract
Healing large bone defects remains challenging in orthopedic surgery and is often associated with poor outcomes and complications. A major issue with bioengineered constructs is achieving a continuous interface between host bone and graft to enhance biological processes and mechanical stability. In this study, we have developed a new bioengineering strategy to produce oriented biocompatible 3D PLGA/aCaP nanocomposites with enhanced osseointegration. Decellularized scaffolds -containing only extracellular matrix- or scaffolds seeded with adipose-derived mesenchymal stromal cells were tested in a mouse model for critical size bone defects. In parallel to micro-CT analysis, SAXS tensor tomography and 2D scanning SAXS were employed to determine the 3D arrangement and nanostructure within the critical-sized bone. Both newly developed scaffold types, seeded with cells or decellularized, showed high osseointegration, higher bone quality, increased alignment of collagen fibers and optimal alignment and size of hydroxyapatite minerals.
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Affiliation(s)
- Elisa A Casanova
- Department of Trauma Surgery, University of Zurich, University Hospital Zurich, Zurich, Switzerland
| | | | - Lisa Stähli
- Department of Trauma Surgery, University of Zurich, University Hospital Zurich, Zurich, Switzerland
| | - Kevin Arnke
- Department of Trauma Surgery, University of Zurich, University Hospital Zurich, Zurich, Switzerland
| | - Olivier Gröninger
- Institute for Chemical and Bioengineering, ETH Zurich, Zurich, Switzerland
| | - Melanie Generali
- Institute for Regenerative Medicine (IREM), Center for Therapy Development and Good Manufacturing Practice, University of Zurich, Zurich, Switzerland
| | - Yvonne Neldner
- Department of Trauma Surgery, University of Zurich, University Hospital Zurich, Zurich, Switzerland
| | - Simon Tiziani
- Department of Trauma Surgery, University of Zurich, University Hospital Zurich, Zurich, Switzerland
| | - Ana Perez Dominguez
- Oral Biotechnology and Bioengineering, Department of Cranio-Maxillofacial and Oral Surgery, Center for Dental Medicine, University of Zurich, Zurich, Switzerland
| | | | - Zirui Gao
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Christian Appel
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Leonard C Nielsen
- Department of Physics, Chalmers University of Technology, Gothenburg, Sweden
| | - Marios Georgiadis
- Department of Radiology, Stanford School of Medicine, Stanford, CA, USA
| | - Franz E Weber
- Oral Biotechnology and Bioengineering, Department of Cranio-Maxillofacial and Oral Surgery, Center for Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Wendelin Stark
- Institute for Chemical and Bioengineering, ETH Zurich, Zurich, Switzerland
| | - Hans-Christoph Pape
- Department of Trauma Surgery, University of Zurich, University Hospital Zurich, Zurich, Switzerland
| | - Paolo Cinelli
- Department of Trauma Surgery, University of Zurich, University Hospital Zurich, Zurich, Switzerland; Center for Applied Biotechnology and Molecular Medicine (CABMM), University of Zurich, Zurich, Switzerland.
| | - Marianne Liebi
- Department of Physics, Chalmers University of Technology, Gothenburg, Sweden; Centre for X-ray Analytics, Swiss Federal Laboratories for Materials Science and Technology (EMPA), St. Gallen, Switzerland
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2
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Brunner JD, Jakob RP, Schulze T, Neldner Y, Moroni A, Thiel G, Maier T, Schenck S. Structural basis for ion selectivity in TMEM175 K + channels. eLife 2020; 9:e53683. [PMID: 32267231 PMCID: PMC7176437 DOI: 10.7554/elife.53683] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 04/07/2020] [Indexed: 12/14/2022] Open
Abstract
The TMEM175 family constitutes recently discovered K+channels that are important for autophagosome turnover and lysosomal pH regulation and are associated with the early onset of Parkinson Disease. TMEM175 channels lack a P-loop selectivity filter, a hallmark of all known K+ channels, raising the question how selectivity is achieved. Here, we report the X-ray structure of a closed bacterial TMEM175 channel in complex with a nanobody fusion-protein disclosing bound K+ ions. Our analysis revealed that a highly conserved layer of threonine residues in the pore conveys a basal K+ selectivity. An additional layer comprising two serines in human TMEM175 increases selectivity further and renders this channel sensitive to 4-aminopyridine and Zn2+. Our findings suggest that large hydrophobic side chains occlude the pore, forming a physical gate, and that channel opening by iris-like motions simultaneously relocates the gate and exposes the otherwise concealed selectivity filter to the pore lumen.
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Affiliation(s)
- Janine D Brunner
- Department of Biochemistry, University of ZürichZürichSwitzerland
- Department Biozentrum, University of BaselBaselSwitzerland
- Laboratory of Biomolecular Research, Paul Scherrer InstitutVilligenSwitzerland
- VIB-VUB Center for Structural Biology, VIBBrusselsBelgium
- Structural Biology Brussels, Vrije Universiteit BrusselBrusselsBelgium
| | - Roman P Jakob
- Department Biozentrum, University of BaselBaselSwitzerland
| | - Tobias Schulze
- Membrane Biophysics, Technical University of DarmstadtDarmstadtGermany
| | - Yvonne Neldner
- Department of Biochemistry, University of ZürichZürichSwitzerland
| | - Anna Moroni
- Department of Biosciences, University of MilanoMilanItaly
| | - Gerhard Thiel
- Membrane Biophysics, Technical University of DarmstadtDarmstadtGermany
| | - Timm Maier
- Department Biozentrum, University of BaselBaselSwitzerland
| | - Stephan Schenck
- Department of Biochemistry, University of ZürichZürichSwitzerland
- Laboratory of Biomolecular Research, Paul Scherrer InstitutVilligenSwitzerland
- VIB-VUB Center for Structural Biology, VIBBrusselsBelgium
- Structural Biology Brussels, Vrije Universiteit BrusselBrusselsBelgium
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3
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Paulino C, Kalienkova V, Lam AK, Neldner Y, Dutzler R. Structural Basis for Anion Conduction and Gating in the Calcium-Activated Chloride-Channel TMEM16A. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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4
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Schenck S, Kunz L, Sahlender D, Pardon E, Geertsma ER, Savtchouk I, Suzuki T, Neldner Y, Štefanić S, Steyaert J, Volterra A, Dutzler R. Generation and Characterization of Anti-VGLUT Nanobodies Acting as Inhibitors of Transport. Biochemistry 2017; 56:3962-3971. [DOI: 10.1021/acs.biochem.7b00436] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Stephan Schenck
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Laura Kunz
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Daniela Sahlender
- Department
of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - Els Pardon
- VIB
Center for Structural Biology, VIB, 1050 Brussels, Belgium
- Structural
Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Eric R. Geertsma
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Institute
of Biochemistry, Biocenter, Goethe-University Frankfurt, Max-von-Laue-Straβe
9, 60438 Frankfurt
am Main, Germany
| | - Iaroslav Savtchouk
- Department
of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - Toshiharu Suzuki
- Department
of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Yvonne Neldner
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Saša Štefanić
- Institute
of Parasitology, University of Zurich, Winterthurerstrasse 266a, 8057 Zurich, Switzerland
| | - Jan Steyaert
- VIB
Center for Structural Biology, VIB, 1050 Brussels, Belgium
- Structural
Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Andrea Volterra
- Department
of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - Raimund Dutzler
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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5
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Paulino C, Neldner Y, Lam AKM, Kalienkova V, Brunner JD, Schenck S, Dutzler R. Structural basis for anion conduction in the calcium-activated chloride channel TMEM16A. eLife 2017; 6:e26232. [PMID: 28561733 PMCID: PMC5470873 DOI: 10.7554/elife.26232] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 04/11/2017] [Indexed: 12/11/2022] Open
Abstract
The calcium-activated chloride channel TMEM16A is a member of a conserved protein family that comprises ion channels and lipid scramblases. Although the structure of the scramblase nhTMEM16 has defined the architecture of the family, it was unknown how a channel has adapted to cope with its distinct functional properties. Here we have addressed this question by the structure determination of mouse TMEM16A by cryo-electron microscopy and a complementary functional characterization. The protein shows a similar organization to nhTMEM16, except for changes at the site of catalysis. There, the conformation of transmembrane helices constituting a membrane-spanning furrow that provides a path for lipids in scramblases has changed to form an enclosed aqueous pore that is largely shielded from the membrane. Our study thus reveals the structural basis of anion conduction in a TMEM16 channel and it defines the foundation for the diverse functional behavior in the TMEM16 family.
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Affiliation(s)
- Cristina Paulino
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Yvonne Neldner
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Andy KM Lam
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | | | | | - Stephan Schenck
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Raimund Dutzler
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
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6
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Chang YN, Shaik FR, Neldner Y, Geertsma ER. Production, Purification and Crystallization of a ProkaryoticSLC26 Homolog for Structural Studies. Bio Protoc 2017; 7:e2116. [PMID: 34458442 DOI: 10.21769/bioprotoc.2116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 11/07/2016] [Accepted: 01/06/2017] [Indexed: 11/02/2022] Open
Abstract
The SLC26 or SulP proteins constitute a large family of anion transporters that are ubiquitously expressed in pro- and eukaryotes. In human, SLC26 proteins perform important roles in ion homeostasis and malfunctioning of selected members is associated with diseases. This protocol details the production and crystallization of a prokaryotic SLC26 homolog, termed SLC26Dg, from Deinococcus geothermalis. Following these instructions we obtained well-folded and homogenous material of the membrane protein SLC26Dg and the nanobody Nb5776 that enabled us to crystallize the complex and determine its structure ( Geertsma et al., 2015 ). The procedure may be adapted to purify and crystallize other membrane protein complexes.
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Affiliation(s)
- Yung-Ning Chang
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Farooque R Shaik
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland
| | - Yvonne Neldner
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Eric R Geertsma
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany
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7
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Geertsma ER, Chang YN, Shaik FR, Neldner Y, Pardon E, Steyaert J, Dutzler R. Erratum: Corrigendum: Structure of a prokaryotic fumarate transporter reveals the architecture of the SLC26 family. Nat Struct Mol Biol 2016; 23:462. [DOI: 10.1038/nsmb0516-462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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8
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Geertsma ER, Chang YN, Shaik FR, Neldner Y, Pardon E, Steyaert J, Dutzler R. Structure of a prokaryotic fumarate transporter reveals the architecture of the SLC26 family. Nat Struct Mol Biol 2015; 22:803-8. [PMID: 26367249 DOI: 10.1038/nsmb.3091] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 08/20/2015] [Indexed: 12/18/2022]
Abstract
The SLC26 family of membrane proteins combines a variety of functions within a conserved molecular scaffold. Its members, besides coupled anion transporters and channels, include the motor protein Prestin, which confers electromotility to cochlear outer hair cells. To gain insight into the architecture of this protein family, we characterized the structure and function of SLC26Dg, a facilitator of proton-coupled fumarate symport, from the bacterium Deinococcus geothermalis. Its modular structure combines a transmembrane unit and a cytoplasmic STAS domain. The membrane-inserted domain consists of two intertwined inverted repeats of seven transmembrane segments each and resembles the fold of the unrelated transporter UraA. It shows an inward-facing, ligand-free conformation with a potential substrate-binding site at the interface between two helix termini at the center of the membrane. This structure defines the common framework for the diverse functional behavior of the SLC26 family.
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Affiliation(s)
- Eric R Geertsma
- Department of Biochemistry, University of Zurich, Zurich, Switzerland.,Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Yung-Ning Chang
- Department of Biochemistry, University of Zurich, Zurich, Switzerland.,Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Frankfurt am Main, Germany
| | - Farooque R Shaik
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Yvonne Neldner
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Els Pardon
- Structural Biology Research Center, Vlaams Instituut voor Biotechnologie, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Jan Steyaert
- Structural Biology Research Center, Vlaams Instituut voor Biotechnologie, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Raimund Dutzler
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
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9
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Abstract
Opioid receptors, like many G protein-coupled receptors (GPCRs), are notoriously unstable in detergents. We have now developed a more stable variant of the mu-opioid receptor (MOR) and also a method for the immobilization of solubilized, functional opioid receptors on a solid phase (magnetic beads). Starting with the intrinsically more stable kappa-opioid receptor (KOR), we optimized the conditions (i.e. detergents and stabilizing ligands) for receptor extraction from lipid bilayers of HEK293T cells to obtain maximal amounts of functional, immobilized receptor. After immobilization, the ligand binding profile remains the same as observed for the membrane-embedded receptor. For the immobilized wild-type mu-opioid receptor, however, no conditions were found under which ligand binding capacity was retained. To solve this problem, we engineered the receptor chimera KKM where the N-terminus and the first transmembrane helix (TM1) of wild-type MOR is exchanged for the homologous receptor parts of the wild-type KOR. This hybrid receptor behaves exactly as the wild-type MOR in functional assays. Interestingly, the modified MOR is expressed at six times higher levels than wild-type MOR and is similarly stable as wild-type KOR after immobilization. Hence the immobilized MOR, represented by the chimera KKM, is now also amenable for biophysical characterization. These results are encouraging for future stability engineering of GPCRs.
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Affiliation(s)
- David Ott
- Biochemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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