1
|
Qiang W, Kengwerere M, Zhao W, Scott FJ, Wutoh-Hughes X, Wang T, Mentink-Vigier F. Heterotypic Interactions between the 40- and 42-Residue Isoforms of β-Amyloid Peptides on Lipid Bilayer Surfaces. ACS Chem Neurosci 2023; 14:4153-4162. [PMID: 37991929 PMCID: PMC10867818 DOI: 10.1021/acschemneuro.3c00523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2023] Open
Abstract
Co-aggregation involving different amyloidogenic sequences has been emphasized recently in the modified amyloid cascade hypothesis. Yet, molecular-level interactions between two predominant β-amyloid peptide sequences, Aβ40 and Aβ42, in the fibrillation process in membrane-mimicked environments remain unclear. Here, we report biophysical evidence that demonstrates the molecular-level interactions between Aβ40 and Aβ42 at the membrane-associated conucleation stage using dynamic nuclear polarization-enhanced solid-state NMR spectroscopy. These residue-specific contacts are distinguished from those reported in mature fibrils formed by either Aβ40 or Aβ42. Meanwhile, site-specific interactions between Aβ and lipid molecules and modulation of microsecond-time-scale lipid dynamics are observed, which may be responsible for the more rapid and significant membrane content leakage compared to that with Aβ40 alone.
Collapse
Affiliation(s)
- Wei Qiang
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, NY 13902, USA
| | - Maurine Kengwerere
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, NY 13902, USA
| | - Wancheng Zhao
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Faith J. Scott
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Xyomara Wutoh-Hughes
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, NY 13902, USA
| | - Tuo Wang
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Frederic Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| |
Collapse
|
2
|
Wachira FW, Githirwa DC, McPartlon T, Nazarenko V, Gonzales JJC, Gazura MM, Leen C, Clary HR, Alston C, Klees LM, Yao L, An M. D-to-E and T19V Variants of the pH-Low Insertion Peptide and Their Doxorubicin Conjugates Interact with Membrane at Higher pH Ranges Than WT. Biochemistry 2023; 62:2997-3011. [PMID: 37793002 DOI: 10.1021/acs.biochem.3c00218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
To improve targeted cargo delivery to cancer cells, pH-Low Insertion Peptide (pHLIP) variants were developed to interact with the membrane at pH values higher than those of the WT. The Asp-to-Glu variants aim to increase side chain pKa without disturbing the sequence of protonations that underpin membrane insertion. The Thr19 variants represent efforts to perturb the critical Pro20 residue. To study the effect of cargo on pHLIP insertion, doxorubicin (Dox), a fluorescent antineoplastic drug, was conjugated to selected variants near the inserting C-terminus. Variants and conjugates were characterized on a POPC membrane using Trp and Dox fluorescence methods to define the entire pH range of insertion (pHinitial-pHfinal). Compared to WT with a pHi-pHf range of 6.7-5.6, D25E-D31E-D33E, D14E-D25E-D31E-D33E, and T19V-D25E variants demonstrated higher pHi-pHf ranges of 7.3-6.1, 7.3-6.3, and 8.2-5.4, respectively. The addition of Dox expanded the pHi-pHf range, mainly by shifting pHi to higher pH values (e.g., WT pHLIP-Dox has a pHi-pHf range of 7.7-5.2). Despite the low Hill coefficient observed for the conjugates, D14E-D25E-D31E-D33E pHLIP-Dox completed insertion by a pHf of 5.7. However, the Dox cargo remained in the hydrophobic membrane interior after pHLIP insertion, which may impede drug release. Finally, a logistic function can describe pHLIP insertion as a peripheral-to-TM (start-to-finish) two-state transition; wherever possible, we discuss data deviating from such sigmoidal fitting in support of the idea that pH-specific intermediate states distinct from the initial peripheral state and the final TM state exist at intervening pH values.
Collapse
Affiliation(s)
- Faith W Wachira
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Dancan C Githirwa
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Thomas McPartlon
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Vladyslav Nazarenko
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Jerel J C Gonzales
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Makenzie M Gazura
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Caitlin Leen
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Hannah R Clary
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Claire Alston
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Lukas M Klees
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| | - Lan Yao
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
- Department of Physics, SUNY, Binghamton University, Binghamton, New York 13902, United States
| | - Ming An
- Department of Chemistry, State University of New York (SUNY), Binghamton University, Binghamton, New York 13902, United States
| |
Collapse
|
3
|
Kenyaga JM, Cheng Q, Qiang W. Early-Stage β-Amyloid-Membrane Interactions Modulate Lipid Dynamics and Influence Structural Interfaces and Fibrillation. J Biol Chem 2022; 298:102491. [PMID: 36115457 PMCID: PMC9556791 DOI: 10.1016/j.jbc.2022.102491] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 11/02/2022] Open
Abstract
Molecular interactions between β-amyloid (Aβ) peptide and membranes contribute to the neuronal toxicity of Aβ and the pathology of Alzheimer's disease (AD). Neuronal plasma membranes serve as biologically relevant environments for the Aβ aggregation process as well as affect the structural polymorphisms of Aβ aggregates. However, the nature of these interactions is unknown. Here, we utilized solid-state NMR spectroscopy to explore the site-specific interactions between Aβ peptides and lipids in synaptic plasma membranes at the membrane-associated nucleation stage. The key results show that different segments in the hydrophobic sequence of Aβ initiate membrane binding and inter-strand assembling. We demonstrate early-stage Aβ-lipid interactions modulate lipid dynamics, leading to more rapid lipid headgroup motion and reduced lateral diffusive motion. These early events influence the structural polymorphisms of yielded membrane-associated Aβ fibrils with distinct C-terminal quaternary interface structure compared to fibrils grown in aqueous solutions. Based on our results, we propose a schematic mechanism by which Aβ-lipid interactions drive membrane-associated nucleation processes, providing molecular insights into the early events of fibrillation in biological environments.
Collapse
Affiliation(s)
- June M Kenyaga
- Department of Chemistry, Binghamton University, the State University of New York
| | - Qinghui Cheng
- Department of Chemistry, Binghamton University, the State University of New York
| | - Wei Qiang
- Department of Chemistry, Binghamton University, the State University of New York.
| |
Collapse
|
4
|
Vasquez‐Montes V, Tyagi V, Sikorski E, Kyrychenko A, Freites JA, Thévenin D, Tobias DJ, Ladokhin AS. Ca 2+ -dependent interactions between lipids and the tumor-targeting peptide pHLIP. Protein Sci 2022; 31:e4385. [PMID: 36040255 PMCID: PMC9366937 DOI: 10.1002/pro.4385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/31/2022] [Accepted: 06/24/2022] [Indexed: 11/08/2022]
Abstract
Cancerous tissues undergo extensive changes to their cellular environments that differentiate them from healthy tissues. These changes include changes in extracellular pH and Ca2+ concentrations, and the exposure of phosphatidylserine (PS) to the extracellular environment, which can modulate the interaction of peptides and proteins with the plasma membrane. Deciphering the molecular mechanisms of such interactions is critical for advancing the knowledge-based design of cancer-targeting molecular tools, such as pH-low insertion peptide (pHLIP). Here, we explore the effects of PS, Ca2+ , and peptide protonation state on the interactions of pHLIP with lipid membranes. Cellular studies demonstrate that exposed PS on the plasma membrane promotes pHLIP targeting. The magnitude of this effect is dependent on extracellular Ca2+ concentration, indicating that divalent cations play an important role in pHLIP targeting in vivo. The targeting mechanism is further explored with a combination of fluorescence and circular dichroism experiments in model membranes and microsecond-timescale all-atom molecular dynamics simulations. Our results demonstrate that Ca2+ is engaged in coupling peptide-lipid interactions in the unprotonated transmembrane conformation of pHLIP. The simulations reveal that while the pH-induced insertion leads to a strong depletion of PS around pHLIP, the Ca2+ -induced insertion has the opposite effect. Thus, extracellular levels of Ca2+ are crucial to linking cellular changes in membrane lipid composition with the selective targeting and insertion of pHLIP. The characterized Ca2+ -dependent coupling between pHLIP sidechains and PS provides atomistic insights into the general mechanism for lipid-coupled regulation of protein-membrane insertion by divalent cations.
Collapse
Affiliation(s)
- Victor Vasquez‐Montes
- Department of Biochemistry and Molecular BiologyThe University of Kansas Medical CenterKansas CityKansasUSA
| | - Vivek Tyagi
- Department of ChemistryUniversity of CaliforniaIrvineCaliforniaUSA
| | - Eden Sikorski
- Department of ChemistryLehigh UniversityBethlehemPennsylvaniaUSA
| | - Alexander Kyrychenko
- Institute of Chemistry and School of Chemistry, V. N. Karazin Kharkiv National UniversityKharkivUkraine
| | | | - Damien Thévenin
- Department of ChemistryLehigh UniversityBethlehemPennsylvaniaUSA
| | | | - Alexey S. Ladokhin
- Department of Biochemistry and Molecular BiologyThe University of Kansas Medical CenterKansas CityKansasUSA
| |
Collapse
|
5
|
Ataka K, Drauschke J, Stulberg V, Koksch B, Heberle J. pH-induced insertion of pHLIP into a lipid bilayer: In-situ SEIRAS characterization of a folding intermediate at neutral pH. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183873. [PMID: 35104491 DOI: 10.1016/j.bbamem.2022.183873] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 11/22/2021] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
The pH low insertion peptide (pHLIP) is a pH-sensitive cell penetrating peptide that transforms from an unstructured coil on the membrane surface at pH > 7, to a transmembrane (TM) α-helix at pH < 5. By exploiting this unique property, pHLIP attracts interest as a potential tool for drug delivery and visualisation of acidic tissues produced by various maladies such as cancer, inflammation, hypoxia etc. Even though the structures of initial and end states of pHLIP insertion have been widely accepted, the intermediate structures in between these two states are less clear. Here, we have applied in situ Surface-Enhanced Infrared Absorption spectroscopy to examine the pH-induced insertion and folding processes of pHLIP into a solid-supported lipid bilayer. We show that formation of partially helical structure already takes place at pH only slightly below 7.0, but with the helical axis parallel to the membrane surface. The peptide starts to reorientate its helix from horizontal to vertical direction, accompanied by the insertion into the TM region at pH < 6.2. Further insertion into the TM region of the peptide results in an increase of inherent α-helical structure and complete secondary structure formation at pH 5.3. Analysis of the changes of the carboxylate vibrational bands upon pH titration shows two distinctive groups of aspartates and glutamates with pKa values of 4.5 and 6.3, respectively. Comparison to the amide bands of the peptide backbone suggests that the latter Asp/Glu groups are directly involved in the conformational changes of pHLIP in the respective intermediate states.
Collapse
Affiliation(s)
- Kenichi Ataka
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
| | - Janina Drauschke
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Valentina Stulberg
- Institute for Chemistry and Biochemistry, Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Arnimallee 20, 14195, Berlin, Germany
| | - Beate Koksch
- Institute for Chemistry and Biochemistry, Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Arnimallee 20, 14195, Berlin, Germany
| | - Joachim Heberle
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
| |
Collapse
|
6
|
Otieno SA, Qiang W. Roles of key residues and lipid dynamics reveal pHLIP-membrane interactions at intermediate pH. Biophys J 2021; 120:4649-4662. [PMID: 34624273 PMCID: PMC8595900 DOI: 10.1016/j.bpj.2021.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/16/2021] [Accepted: 10/01/2021] [Indexed: 11/16/2022] Open
Abstract
The pH-low insertion peptide (pHLIP) and its analogs sense the microenvironmental pH variations in tumorous cells and serve as useful anticancer drug deliveries. The pHLIP binds peripherally to membranes and adopts random coil conformation at the physiological pH. The peptide switches from random coil to α-helical conformation and inserts unidirectionally into membrane bilayers when pH drops below a critical transition value that has been routinely determined by the Trp fluorescence spectroscopy. Recent high-resolution studies using solid-state NMR spectroscopy revealed the presence of thermodynamically stable intermediate states of membrane-associated pHLIP around the fluorescence-based transition pH-value. However, the molecular structural features and their mechanistic roles of these intermediate states in the pH-driven membrane insertion process of pHLIP remain largely unknown. This work utilizes solid-state NMR spectroscopy to explore 1) the mechanistic roles of key proline and arginine residues within the pHLIP sequence at intermediate pH-values, and 2) the changes in lipid dynamics at intermediate pH-values in multiple types of model bilayers with anionic phospholipid and/or cholesterol. Our results demonstrate several molecular structural and dynamics changes at around the transition pH-values, including the isomerization of proline-threonine backbone configuration, breaking of arginine-aspartic acid salt bridge and the formation of arginine-lipid interactions, and a universal decreasing of dynamics in lipid headgroups and alkyl chains. Overall, the outcomes provide important insights on the molecular interactions between pHLIP and membrane bilayers at intermediate pH-values and, therefore, prompt the understanding of pH-driven membrane insertion process of this anticancer drug-delivering peptide.
Collapse
Affiliation(s)
- Sarah A Otieno
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, New York
| | - Wei Qiang
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, New York.
| |
Collapse
|
7
|
Zhang X, Zhang Y, Tang S, Ma S, Shen Y, Chen Y, Tong Q, Li Y, Yang J. Hydrophobic Gate of Mechanosensitive Channel of Large Conductance in Lipid Bilayers Revealed by Solid-State NMR Spectroscopy. J Phys Chem B 2021; 125:2477-2490. [DOI: 10.1021/acs.jpcb.0c07487] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Xuning Zhang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Yan Zhang
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Siyang Tang
- Children’s Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Shaojie Ma
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Yang Shen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - Yanke Chen
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Qiong Tong
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yuezhou Li
- Children’s Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Jun Yang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology and the Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430074, China
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| |
Collapse
|
8
|
Burns V, Mertz B. Using Simulation to Understand the Role of Titration on the Stability of a Peptide-Lipid Bilayer Complex. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12272-12280. [PMID: 32988206 PMCID: PMC7778881 DOI: 10.1021/acs.langmuir.0c02038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The pH-low insertion peptide (pHLIP) is an anionic membrane-active peptide with promising potential for applications in imaging of cancer tumors and targeted delivery of chemotherapeutics. The key advantage of pHLIP lies in its acid sensitivity: in acidic cellular environments, pHLIP can insert unidirectionally into the plasma membrane. Partitioning-folding coupling is triggered by titration of the acidic residues in pHLIP, transforming pHLIP from a hydrophilic to a hydrophobic peptide. Despite this knowledge, the reverse pathway that leads to exit of the peptide from the plasma membrane is poorly understood. Our hypothesis is that sequential deprotonation of pHLIP is a prerequisite for exit of the peptide from the plasma membrane. We carried out molecular dynamics (MD) simulations to characterize the effect that deprotonation of the acidic residues of pHLIP has on the stability of the peptide when inserted into a model lipid bilayer of 1-palmitoyl-2-oleoyl-sn-3-phosphocholine (POPC). Initiation of the exit mechanism is facilitated by a complex relationship between the peptide, bulk solvent, and the membrane environment. As the N-terminal acidic residues of pHLIP are deprotonated, localized loss of helicity drives unfolding of the peptide and more pronounced interactions with the bilayer at the lipid-water interface. Deprotonation of the C-terminal acidic residues (D25, D31, D33, and E34) leads to further loss of secondary structure distal from the C-terminus, as well as formation of a water channel that stabilizes the orientation of pHLIP parallel to the membrane normal. Together, these results help explain how stabilization of intermediates between the surface-bound and inserted states of pHLIP occur and provide insights into rational design of pHLIP variants with modified abilities of insertion.
Collapse
Affiliation(s)
- Violetta Burns
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Blake Mertz
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
- WVU Cancer Institute, West Virginia University, Morgantown, West Virginia 26506, United States
| |
Collapse
|
9
|
Qiang W, Doherty KE, Klees LM, Tobin-Miyaji Y. Time-Dependent Lipid Dynamics, Organization and Peptide-Lipid Interaction in Phospholipid Bilayers with Incorporated β-Amyloid Oligomers. J Phys Chem Lett 2020; 11:8329-8336. [PMID: 32931283 PMCID: PMC7647725 DOI: 10.1021/acs.jpclett.0c01967] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Nonfibrillar β-amyloid (Aβ) oligomers are considered as major neurotoxic species in the pathology of Alzheimer's disease. The presence of Aβ oligomers was shown to cause membrane disruptions in a broad range of model systems. However, the molecular basis of such a disruption process remains unknown. We previously demonstrated that membrane-incorporated 40-residue Aβ (Aβ40) oligomers could form coaggregates with phospholipids. This process occurred more rapidly than the fibrillization of Aβ40 and led to more severe membrane disruption. The present study probes the time-dependent changes in lipid dynamics, bilayer structures, and peptide-lipid interactions along the time course of the oligomer-induced membrane disruption, using solid-state NMR spectroscopy. Our results suggest the presence of certain intermediate states with phospholipid molecules entering the C-terminal hydrogen-bonding networks of the Aβ40 oligomeric cores. This work provides insights on the molecular mechanisms of Aβ40-oligomer-induced membrane disruption.
Collapse
Affiliation(s)
- Wei Qiang
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, New York 13902
| | - Katelynne E. Doherty
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, New York 13902
| | - Lukas M. Klees
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, New York 13902
| | - Yuto Tobin-Miyaji
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, New York 13902
| |
Collapse
|
10
|
Abstract
To advance mechanistic understanding of membrane-associated peptide folding and insertion, we have studied the kinetics of three single tryptophan pHLIP (pH-Low Insertion Peptide) variants, where tryptophan residues are located near the N terminus, near the middle, and near the inserting C-terminal end of the pHLIP transmembrane helix. Single-tryptophan pHLIP variants allowed us to probe different parts of the peptide in the pathways of peptide insertion into the lipid bilayer (triggered by a pH drop) and peptide exit from the bilayer (triggered by a rise in pH). By using pH jumps of different magnitudes, we slowed down the processes and established the intermediates that helped us to understand the principles of insertion and exit. The obtained results should also aid the applications in medicine that are now entering the clinic.
Collapse
|
11
|
Reshetnyak YK, Moshnikova A, Andreev OA, Engelman DM. Targeting Acidic Diseased Tissues by pH-Triggered Membrane-Associated Peptide Folding. Front Bioeng Biotechnol 2020; 8:335. [PMID: 32411684 PMCID: PMC7198868 DOI: 10.3389/fbioe.2020.00335] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 03/26/2020] [Indexed: 12/19/2022] Open
Abstract
The advantages of targeted therapy have motivated many efforts to find distinguishing features between the molecular cell surface landscapes of diseased and normal cells. Typically, the features have been proteins, lipids or carbohydrates, but other approaches are emerging. In this discussion, we examine the use of cell surface acidity as a feature that can be exploited by using pH-sensitive peptide folding to target agents to diseased cell surfaces or cytoplasms.
Collapse
Affiliation(s)
- Yana K Reshetnyak
- Department of Physics, The University of Rhode Island, Kingston, RI, United States
| | - Anna Moshnikova
- Department of Physics, The University of Rhode Island, Kingston, RI, United States
| | - Oleg A Andreev
- Department of Physics, The University of Rhode Island, Kingston, RI, United States
| | - Donald M Engelman
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| |
Collapse
|
12
|
Rao BD, Chakraborty H, Chaudhuri A, Chattopadhyay A. Differential sensitivity of pHLIP to ester and ether lipids. Chem Phys Lipids 2019; 226:104849. [PMID: 31836521 DOI: 10.1016/j.chemphyslip.2019.104849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/05/2019] [Accepted: 12/05/2019] [Indexed: 10/25/2022]
Abstract
pH (low) insertion peptide (pHLIP) is a polypeptide from the third transmembrane helix of bacteriorhodopsin. The pH-dependent membrane insertion of pHLIP has been conveniently exploited for translocation of cargo molecules and as a novel imaging agent in cancer biology due to low extracellular pH in cancer tissues. Although the application of pHLIP for imaging tumor and targeted drug delivery is well studied, literature on pHLIP-membrane interaction is relatively less studied. Keeping this in mind, we explored the differential interaction of pHLIP with ester and ether lipid membranes utilizing fluorescence and CD spectroscopy. We report, for the first time, higher binding affinity of pHLIP toward ether lipid relative to ester lipid membranes. There results gain relevance since Halobacterium halobium (source of bacteriorhodopsin) is enriched with ether lipids. In addition, we monitored the difference in microenvironment around pHLIP tryptophans utilizing red edge excitation shift and observed increased motional restriction of water molecules in the interfacial region in ether lipid membranes. These changes were accompanied with increase in helicity of pHLIP in ether lipid relative to ester lipid membranes. Our results assume further relevance since ether lipids are upregulated in cancer cells and have emerged as potential biomarkers of various diseases including cancer.
Collapse
Affiliation(s)
- Bhagyashree D Rao
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India; CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad, 500 007, India; Academy of Scientific and Innovative Research, Ghaziabad, 201 002, India
| | - Hirak Chakraborty
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India; School of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Odisha, 768 019, India
| | - Arunima Chaudhuri
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India
| | - Amitabha Chattopadhyay
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India; Academy of Scientific and Innovative Research, Ghaziabad, 201 002, India.
| |
Collapse
|
13
|
Vasquez-Montes V, Gerhart J, Thévenin D, Ladokhin AS. Divalent Cations and Lipid Composition Modulate Membrane Insertion and Cancer-Targeting Action of pHLIP. J Mol Biol 2019; 431:5004-5018. [PMID: 31689432 PMCID: PMC6920566 DOI: 10.1016/j.jmb.2019.10.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 10/24/2019] [Accepted: 10/24/2019] [Indexed: 02/06/2023]
Abstract
The pH-Low Insertion Peptide (pHLIP) has emerged as an important tool for targeting cancer cells; it has been assumed that its targeting mechanism depends solely on the mild acidic environment surrounding tumors. Here, we examine the role of Ca2+ and Mg2+ on pHLIP's insertion, cellular targeting, and drug delivery. We demonstrate that physiologically relevant concentrations of either cation can shift the protonation-dependent transition by up to several pH units toward basic pH and induce substantial protonation-independent transmembrane insertion of pHLIP at pH as high as 10. Consistent with these results, the ability of pHLIP to deliver the cytotoxic compound monomethyl-auristatin-F to HeLa cells is increased several fold in presence of Ca2+. Complementary measurements with model membranes confirmed this Ca2+/Mg2+-dependent membrane-insertion mechanism. The magnitude of this alternative Ca2+/Mg2+-dependent effect is also modulated by lipid composition-specifically by the presence of phosphatidylserine-providing new clues to pHLIP's unique tumor-targeting ability in vivo. These results exemplify the complex coupling between protonation of anionic residues and lipid-selective targeting by divalent cations, which is relevant to the general signaling on membrane interfaces.
Collapse
Affiliation(s)
- Victor Vasquez-Montes
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Janessa Gerhart
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, PA, 18015, USA
| | - Damien Thévenin
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, PA, 18015, USA
| | - Alexey S Ladokhin
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, KS, 66160, USA.
| |
Collapse
|
14
|
Westerfield J, Gupta C, Scott HL, Ye Y, Cameron A, Mertz B, Barrera FN. Ions Modulate Key Interactions between pHLIP and Lipid Membranes. Biophys J 2019; 117:920-929. [PMID: 31422821 DOI: 10.1016/j.bpj.2019.07.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 07/05/2019] [Accepted: 07/22/2019] [Indexed: 02/04/2023] Open
Abstract
The pH-low insertion peptide (pHLIP) is used for targeted delivery of drug cargoes to acidic tissues such as tumors. The extracellular acidosis found in solid tumors triggers pHLIP to transition from a membrane-adsorbed state to fold into a transmembrane α-helix. Different factors influence the acidity required for pHLIP to insert into lipid membranes. One of them is the lipid headgroup composition, which defines the electrostatic profile of the membrane. However, the molecular interactions that drive the adsorption of pHLIP to the bilayer surface are poorly understood. In this study, we combine biophysical experiments and all-atom molecular dynamics simulations to understand the role played by electrostatics in the interaction between pHLIP and a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer. We observed that the solution ionic strength affects the structure of pHLIP at the membrane surface as well as the acidity needed for different steps in the membrane insertion process. In particular, our simulations revealed that an increase in ionic strength affected both pHLIP and the bilayer; the coordination of sodium ions with the C-terminus of pHLIP led to localized changes in helicity, whereas the coordination of sodium ions with the phosphate moiety of the phosphocholine headgroups had a condensing effect on our model bilayer. These results are relevant to our understanding of environmental influences on the ability of pHLIP to adsorb to the cell membrane and are useful in our fundamental understanding of the absorption of pH-responsive peptides and cell-penetrating peptides.
Collapse
Affiliation(s)
- Justin Westerfield
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee-Knoxville, Knoxville, Tennessee
| | - Chitrak Gupta
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Haden L Scott
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee-Knoxville, Knoxville, Tennessee
| | - Yujie Ye
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee-Knoxville, Knoxville, Tennessee
| | - Alayna Cameron
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee-Knoxville, Knoxville, Tennessee
| | - Blake Mertz
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia; WVU Cancer Institute, West Virginia University, Morgantown, West Virginia.
| | - Francisco N Barrera
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee-Knoxville, Knoxville, Tennessee.
| |
Collapse
|