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Pozzi D, Caracciolo G. Looking Back, Moving Forward: Lipid Nanoparticles as a Promising Frontier in Gene Delivery. ACS Pharmacol Transl Sci 2023; 6:1561-1573. [PMID: 37974625 PMCID: PMC10644400 DOI: 10.1021/acsptsci.3c00185] [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: 08/13/2023] [Indexed: 11/19/2023]
Abstract
Lipid nanoparticles (LNPs) have shown remarkable success in delivering genetic materials like COVID-19 LNP vaccines, such as mRNA-1273/SpikeVax by Moderna and BNT162b2/Comirnaty by BioNTech/Pfizer, as well as siRNA for rare inherited diseases, such as Onpattro from Alnylam Pharmaceuticals. These LNPs are advantageous since they minimize side effects, target specific cells, and regulate payload delivery. There has been a surge of interest in these particles due to their success stories; however, we still do not know much about how they work. This perspective will recapitulate the evolution of lipid-based gene delivery, starting with Felgner's pioneering 1987 PNAS paper, which introduced the initial DNA-transfection method utilizing a synthetic cationic lipid. Our journey takes us to the early 2020s, a time when advancements in bionano interactions enabled us to create biomimetic lipoplexes characterized by a remarkable ability to evade capture by immune cells in vivo. Through this overview, we propose leveraging previous achievements to assist us in formulating improved research goals when optimizing LNPs for medical conditions such as infectious diseases, cancer, and heritable disorders.
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Affiliation(s)
- Daniela Pozzi
- NanoDelivery Lab, Department
of Molecular Medicine, Sapienza University
of Rome, Viale Regina
Elena 291, 00161 Rome, Italy
| | - Giulio Caracciolo
- NanoDelivery Lab, Department
of Molecular Medicine, Sapienza University
of Rome, Viale Regina
Elena 291, 00161 Rome, Italy
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2
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Liao P, Zang S, Wu T, Jin H, Wang W, Huang J, Tang BZ, Yan Y. Generating circularly polarized luminescence from clusterization-triggered emission using solid phase molecular self-assembly. Nat Commun 2021; 12:5496. [PMID: 34535652 PMCID: PMC8448880 DOI: 10.1038/s41467-021-25789-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 08/19/2021] [Indexed: 02/08/2023] Open
Abstract
Purely-organic clusterization-triggered emission (CTE) has displayed promising abilities in bioimaging, chemical sensing, and multicolor luminescence. However, it remains absent in the field of circularly polarized luminescence (CPL) due to the difficulties in well-aligning the nonconventional luminogens. We report a case of CPL generated with CTE using the solid phase molecular self-assembly (SPMSA) of poly-L-lysine (PLL) and oleate ion (OL), that is, the macroscopic CPL supramolecular film self-assembled by the electrostatic complex of PLL/OL under mechanical pressure. Well-defined interface charge distribution, given by lamellar mesophases of OL ions, forces the PLL chains to fold regularly as a requirement of optimal electrostatic interactions. Further facilitated by hydrogen bonding, the through-space conjugation (TSC) of orderly aligned electron-rich O and N atoms leads to CTE-based CPL, which is capable of transferring energy to an acceptor via a Förster resonance energy transfer (FRET) process, making it possible to develop environmentally friendly and economic CPL from sustainable and renewable materials.
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Affiliation(s)
- Peilong Liao
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Shihao Zang
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Tongyue Wu
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Hongjun Jin
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Wenkai Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Jianbin Huang
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Ben Zhong Tang
- Shenzhen Institute of Molecular Aggregate Science and Engineering, School of Science and Engineering, The Chinese University of Hong Kong, 2001 Longxiang Boulevard, Longgang, Shenzhen, Guangdong, 518172, China.
| | - Yun Yan
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
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3
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Beg S, Almalki WH, Khatoon F, Alharbi KS, Alghamdi S, Akhter MH, Khalilullah H, Baothman AA, Hafeez A, Rahman M, Akhter S, Choudhry H. Lipid/polymer-based nanocomplexes in nucleic acid delivery as cancer vaccines. Drug Discov Today 2021; 26:1891-1903. [PMID: 33610757 DOI: 10.1016/j.drudis.2021.02.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 09/13/2020] [Accepted: 02/15/2021] [Indexed: 12/24/2022]
Abstract
Cancer vaccines consist of nucleic acid derivatives such as plasmid DNA, small interfering RNA and mRNA, and can be customized according to the patient's needs. Nanomedicines have proven to be exceptionally good as miniaturized drug carriers, and thus they offer great advantages for delivering cancer vaccines. This review provides an overview of the literature on cancer vaccines, from their inception to current developments in the field.
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Affiliation(s)
- Sarwar Beg
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi, India.
| | - Waleed H Almalki
- Department of Pharmacology and Toxicology, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Fahmida Khatoon
- Department of Biochemistry, College of Medicine, University of Hail, Saudi Arabia
| | - Khalid S Alharbi
- Department of Pharmacology, College of Pharmacy, Jouf University, Sakakah, Saudi Arabia
| | - Saad Alghamdi
- Laboratory Medicine Department, Faculty of Applied Medical Sciences, Umm Al-Qura University, Makkah, Saudi Arabia
| | | | - Habibullah Khalilullah
- Department of Pharmaceutical Chemistry and Pharmacognosy, Unaizah College of Pharmacy, Qassim University, Saudi Arabia
| | - Abdullah A Baothman
- Ministry of National Guard-Health Affairs, King Saud Bin Abdulaziz University for Health Science (KSAU-HS), King Abdullah International Medical Research Center (KAIMARC), Saudi Arabia
| | - Abdul Hafeez
- Glocal School of Pharmacy, Glocal University, Mirzapur Pole, Sahranpur, Uttar Pradesh, India
| | - Mahfoozur Rahman
- Department of Pharmaceutical Sciences, SIHAS, Faculty of Health Science, Sam Higginbottom University of Agriculture, Technology and Sciences, Allahabad, India.
| | - Sohail Akhter
- New Product Development, Global R&D, Sterile ops, TEVA Pharmaceutical Industries Ltd., Aston Ln N, Halton, Preston Brook, Runcorn WA7 3FA, UK; Centre de Biophysique Moléculaire, CNRS UPR4301, Rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - Hani Choudhry
- Department of Biochemistry, Cancer Metabolism & Epigenetic Unit, Faculty of Science, King Fahd Center for Medical Research, King Abdulaziz University, Jeddah, Saudi Arabia
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4
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Zhao Y, Zhao T, Du Y, Cao Y, Xuan Y, Chen H, Zhi D, Guo S, Zhong F, Zhang S. Interaction kinetics of peptide lipids-mediated gene delivery. J Nanobiotechnology 2020; 18:144. [PMID: 33069258 PMCID: PMC7568367 DOI: 10.1186/s12951-020-00707-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 10/09/2020] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND During the course of gene transfection, the interaction kinetics between liposomes and DNA is speculated to play very important role for blood stability, cellular uptake, DNA release and finally transfection efficiency. RESULTS As cationic peptide liposomes exhibited great gene transfer activities both in vitro and in vivo, two peptide lipids, containing a tri-ornithine head (LOrn3) and a mono-ornithine head (LOrn1), were chosen to further clarify the process of liposome-mediated gene delivery in this study. The results show that the electrostatically-driven binding between DNA and liposomes reached nearly 100% at equilibrium, and high affinity of LOrn3 to DNA led to fast binding rate between them. The binding process between LOrn3 and DNA conformed to the kinetics equation: y = 1.663631 × exp (- 0.003427x) + 6.278163. Compared to liposome LOrn1, the liposome LOrn3/DNA lipoplex exhibited a faster and more uniform uptake in HeLa cells, as LOrn3 with a tri-ornithine peptide headgroup had a stronger interaction with the negatively charged cell membrane than LOrn1. The efficient endosomal escape of DNA from LOrn3 lipoplex was facilitated by the acidity in late endosomes, resulting in broken carbamate bonds, as well as the "proton sponge effect" of the lipid. CONCLUSIONS The interaction kinetics is a key factor for DNA transfection efficiency. This work provided insights into peptide lipid-mediated DNA delivery that could guide the development of the next generation of delivery systems for gene therapeutics.
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Affiliation(s)
- Yinan Zhao
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Sciences, Dalian Minzu University, Dalian, 116600, China
| | - Tianyi Zhao
- School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, China
| | - Yanyan Du
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Sciences, Dalian Minzu University, Dalian, 116600, China
| | - Yingnan Cao
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Sciences, Dalian Minzu University, Dalian, 116600, China
| | - Yang Xuan
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Sciences, Dalian Minzu University, Dalian, 116600, China
| | - Huiying Chen
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Sciences, Dalian Minzu University, Dalian, 116600, China
| | - Defu Zhi
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Sciences, Dalian Minzu University, Dalian, 116600, China
| | - Shutao Guo
- Key Laboratory of Functional Polymer Materials of Ministry of Education, State Key Laboratory of Medicinal Chemical Biology and Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China.
| | - Fangli Zhong
- School of Chemistry and Pharmaceutical Engineering, Jilin Institute of Chemical Technology, Jilin, 132022, China.
| | - Shubiao Zhang
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Sciences, Dalian Minzu University, Dalian, 116600, China.
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5
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Li P, Shen Y, Wang L, Lu W, Li W, Chen K, Zhou Y, Shen L, Wei F, Zheng W. The electric double layer structure modulates poly-dT 25 conformation and adsorption kinetics at the cationic lipid bilayer interface. SOFT MATTER 2019; 15:4445-4453. [PMID: 31011740 DOI: 10.1039/c9sm00321e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The conformation and adsorption kinetics of oligonucleotides at lipid membrane interfaces are crucial to their biological functions, but are yet not clearly understood. Poly-dT oligonucleotide molecules have been widely used as primers for reverse translation of RNA molecules, as well as a surface recognition agent for mRNA purification and extraction. In this research, the adsorption processes of poly-dT25 on lipid membranes in different ionic solutions were investigated by sum frequency generation vibrational spectroscopy (SFG-VS) together with a single molecule tracking technique in situ and in real time. These systematic studies provide us with molecular insight into the chemical and physical nature of oligonucleotide-membrane interactions, and show us how the electric double layer (EDL) structure changes the conformation and adsorption kinetics of oligonucleotides. The SFG-VS results indicate that an increase of ionic concentration not only decreases the adsorption density of oligonucleotides but also changes the conformation of oligonucleotides from an elongated conformation to a coiled conformation, causing stronger thermodynamic interactions with membranes, as demonstrated by single molecule tracking techniques. It is also shown that the ionic solution can tune the balance between the surface diffusion rate and solution diffusion rate of oligonucleotides significantly. These results demonstrated that the spectra and kinetics collected by in situ label-free SFG-VS detection and the single molecular tracking technique can provide new molecular insights into the mechanisms of oligonucleotide-membrane interactions. These new understandings may help researchers to control the assembly of oligonucleotide-liposome complexes and to improve the efficiency of transportation and delivery of oligonucleotide molecules.
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Affiliation(s)
- PengHua Li
- Institution for Interdisciplinary Research, & Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, Jianghan University, Wuhan, Hubei 430056, China.
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6
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Wang L, Shen Y, Yang Y, Lu W, Li W, Wei F, Zheng G, Zhou Y, Zheng W, Cao Y. Stern-Layer Adsorption of Oligonucleotides on Lamellar Cationic Lipid Bilayer Investigated by Polarization-Resolved SFG-VS. ACS OMEGA 2017; 2:9241-9249. [PMID: 30023605 PMCID: PMC6045418 DOI: 10.1021/acsomega.7b01214] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 11/29/2017] [Indexed: 06/08/2023]
Abstract
The molecular interaction between the oligonucleotides and lipid membranes is the key to the functions of virus, aptamer, and various oligonucleotide-based materials. In this study, the conformational changes of oligonucleotides (dT25) on lamellar cationic 1,2-dimyristoyl-3-trimethylammonium-propane (DMTAP) bilayer were investigated by polarization-resolved sum frequency generation vibrational spectroscopy (SFG-VS) in situ. The SFG-VS spectra within different wavenumber ranges were analyzed to give conformation details of thymine groups, phosphate groups, and OD/OH groups and to provide a comprehensive and fundamental understanding of the oligonucleotide adsorption on a model bilayer. It is shown that the adsorption of dT25 on DMTAP bilayer reaches maximum at CdT ≈ 500 nM. And the conformation of dT25 molecules change significantly when surface charge of DMTAP bilayer reaches the point of zero charge (PZC) at CdT ≈ 100 nM. Combined spectroscopic evidences also indicate that the formation of electric double layer at the DMTAP/dT25 surface follows the Gouy-Chapman-Stern model. The analysis results also show that the symmetric PO2- stretching mode of oligonucleotide molecules can serve as a sensitive vibration molecular probe for quantifying the oligonucleotide/lipid charge ratio and determine the point of zero charge (PZC) of lipid bilayer surface, which may help researchers to control the layer-by-layer assembly of oligonucleotide-lipid complexes and to improve the efficiency genetic therapy against cancer and viral infections.
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Affiliation(s)
- Liqun Wang
- Institution
for Interdisciplinary Research, & Key Laboratory
of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Life
Science, School of Physics and Information Engineering, and School of Chemical and Environmental
Engineering, Jianghan University, 430056 Wuhan, Hubei, P. R. China
| | - Yang Shen
- Institution
for Interdisciplinary Research, & Key Laboratory
of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Life
Science, School of Physics and Information Engineering, and School of Chemical and Environmental
Engineering, Jianghan University, 430056 Wuhan, Hubei, P. R. China
| | - Yanbo Yang
- Institution
for Interdisciplinary Research, & Key Laboratory
of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Life
Science, School of Physics and Information Engineering, and School of Chemical and Environmental
Engineering, Jianghan University, 430056 Wuhan, Hubei, P. R. China
| | - Wangting Lu
- Institution
for Interdisciplinary Research, & Key Laboratory
of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Life
Science, School of Physics and Information Engineering, and School of Chemical and Environmental
Engineering, Jianghan University, 430056 Wuhan, Hubei, P. R. China
| | - Wenhui Li
- Institution
for Interdisciplinary Research, & Key Laboratory
of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Life
Science, School of Physics and Information Engineering, and School of Chemical and Environmental
Engineering, Jianghan University, 430056 Wuhan, Hubei, P. R. China
| | - Feng Wei
- Institution
for Interdisciplinary Research, & Key Laboratory
of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Life
Science, School of Physics and Information Engineering, and School of Chemical and Environmental
Engineering, Jianghan University, 430056 Wuhan, Hubei, P. R. China
| | - Guang Zheng
- Institution
for Interdisciplinary Research, & Key Laboratory
of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Life
Science, School of Physics and Information Engineering, and School of Chemical and Environmental
Engineering, Jianghan University, 430056 Wuhan, Hubei, P. R. China
| | - Youhua Zhou
- Institution
for Interdisciplinary Research, & Key Laboratory
of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Life
Science, School of Physics and Information Engineering, and School of Chemical and Environmental
Engineering, Jianghan University, 430056 Wuhan, Hubei, P. R. China
| | - Wanquan Zheng
- Institution
for Interdisciplinary Research, & Key Laboratory
of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Life
Science, School of Physics and Information Engineering, and School of Chemical and Environmental
Engineering, Jianghan University, 430056 Wuhan, Hubei, P. R. China
- Institut
des Sciences Moléculaires d’Orsay, Université Paris-Sud, 91405 Orsay Cedex, France
| | - Yuancheng Cao
- Institution
for Interdisciplinary Research, & Key Laboratory
of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Life
Science, School of Physics and Information Engineering, and School of Chemical and Environmental
Engineering, Jianghan University, 430056 Wuhan, Hubei, P. R. China
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7
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Bravo-Anaya L, Macías E, Casillas N, Ramos FC, Fernández V, Soltero J, Larios-Durán E. The Scaling of Electrochemical Parameters of DNA Aqueous Solutions with Concentration and Temperature Through an Electrochemical Impedance Spectroscopy Study. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.03.106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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8
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Structural Behavior of Au-Calf Thymus DNA Interface Estimated Through an Electrochemical Impedance Spectroscopy and Surface Plasmon Resonance Study. Electrochim Acta 2014. [DOI: 10.1016/j.electacta.2014.02.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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Melo AM, Loura LMS, Fernandes F, Villalaín J, Prieto M, Coutinho A. Electrostatically driven lipid-lysozyme mixed fibers display a multilamellar structure without amyloid features. SOFT MATTER 2014; 10:840-850. [PMID: 24651998 DOI: 10.1039/c3sm52586d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Understanding the interactions between anionic lipid membranes and amyloidogenic proteins/peptides is key to elucidate the molecular mechanisms underlying the membrane-driven amyloid fiber formation. Here, hen egg-white lysozyme was used as a model protein to test whether this same process also occurs with non-amyloidogenic lipid-binding proteins/peptides. A complementary set of biophysical techniques was employed to study the structure and dynamics of the lipid-lysozyme mixed fibers produced at a low lipid/protein molar ratio that have been proposed earlier to present "amyloid-like" characteristics. The multilamellar architecture of these elongated mesoscopic structures was established by performing time-resolved Förster resonance energy transfer measurements, at both bulk (ensemble) and single-fiber level. The predominantly oligomeric lysozyme and phospholipids were both found to display significantly decreased lateral mobility when embedded in these mixed fibers. Notably, two-photon microscopy of Laurdan revealed that a pronounced membrane surface dehydration/increased molecular interfacial packing was produced exclusively in these elongated mixed supramolecular fibers present in the highly polymorphic samples. Infrared spectroscopic studies of lysozyme in these samples further showed that this protein did not exhibit a rich β-sheet structure characteristic of amyloid fibrils. These results support the conclusion that negatively charged lipid membranes do not have the general ability to trigger amyloid fibril formation of non-amyloidogenic proteins.
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Affiliation(s)
- Ana M Melo
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
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10
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Loura LMS. Lateral distribution of NBD-PC fluorescent lipid analogs in membranes probed by molecular dynamics-assisted analysis of Förster Resonance Energy Transfer (FRET) and fluorescence quenching. Int J Mol Sci 2012; 13:14545-64. [PMID: 23203080 PMCID: PMC3509596 DOI: 10.3390/ijms131114545] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 10/29/2012] [Accepted: 11/01/2012] [Indexed: 01/19/2023] Open
Abstract
Förster resonance energy transfer (FRET) is a powerful tool used for many problems in membrane biophysics, including characterization of the lateral distribution of lipid components and other species of interest. However, quantitative analysis of FRET data with a topological model requires adequate choices for the values of several input parameters, some of which are difficult to obtain experimentally in an independent manner. For this purpose, atomistic molecular dynamics (MD) simulations can be potentially useful as they provide direct detailed information on transverse probe localization, relative probe orientation, and membrane surface area, all of which are required for analysis of FRET data. This is illustrated here for the FRET pairs involving 1,6-diphenylhexatriene (DPH) as donor and either 1-palmitoyl,2-(6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino] hexanoyl)- sn-glycero-3-phosphocholine (C6-NBD-PC) or 1-palmitoyl,2-(12-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]dodecanoyl)-sn-glycero-3-phosphocholine (C12-NBD-PC) as acceptors, in fluid vesicles of 1,2-dipalmitoyl-sn-3-glycerophosphocholine (DPPC, 50 °C). Incorporation of results from MD simulations improves the statistical quality of model fitting to the experimental FRET data. Furthermore, the decay of DPH in the presence of moderate amounts of C12-NBD-PC (>0.4 mol%) is consistent with non-random lateral distribution of the latter, at variance with C6-NBD-PC, for which aggregation is ruled out up to 2.5 mol% concentration. These conclusions are supported by analysis of NBD-PC fluorescence self-quenching. Implications regarding the relative utility of these probes in membrane studies are discussed.
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Affiliation(s)
- Luís M S Loura
- Faculty of Pharmacy, University of Coimbra, Health Sciences Campus, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
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11
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Kapoor M, Burgess DJ. Physicochemical characterization of anionic lipid-based ternary siRNA complexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:1603-12. [DOI: 10.1016/j.bbamem.2012.03.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/13/2012] [Accepted: 03/14/2012] [Indexed: 01/30/2023]
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12
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Cationic liposome/DNA complexes: from structure to interactions with cellular membranes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 41:815-29. [DOI: 10.1007/s00249-012-0830-8] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 05/15/2012] [Accepted: 05/28/2012] [Indexed: 01/14/2023]
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13
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Fluorescence methods for lipoplex characterization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2694-705. [DOI: 10.1016/j.bbamem.2011.07.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 06/29/2011] [Accepted: 07/15/2011] [Indexed: 11/24/2022]
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14
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Shaheen SM, Akita H, Yamashita A, Katoono R, Yui N, Biju V, Ishikawa M, Harashima H. Quantitative analysis of condensation/decondensation status of pDNA in the nuclear sub-domains by QD-FRET. Nucleic Acids Res 2011; 39:e48. [PMID: 21288880 PMCID: PMC3074156 DOI: 10.1093/nar/gkq1327] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Recent studies indicate that controlling the nuclear decondensation and intra-nuclear localization of plasmid DNA (pDNA) would result in an increased transfection efficiency. In the present study, we established a technology for imaging the nuclear condensation/decondensation status of pDNA in nuclear subdomains using fluorescence resonance energy transfer (FRET) between quantum dot (QD)-labeled pDNA as donor, and rhodamine-labeled polycations as acceptor. The FRET-occurring pDNA/polycation particle was encapsulated in a nuclear delivery system; a tetra-lamellar multifunctional envelope-type nano device (T-MEND), designed to overcome the endosomal membrane and nuclear membrane via step-wise fusion. Nuclear subdomains (i.e. heterochromatin and euchromatin) were distinguished by Hoechst33342 staining. Thereafter, Z-series of confocal images were captured by confocal laser scanning microscopy. pDNA in condensation/decondensation status in heterochromatin or euchromatin were quantified based on the pixel area of the signals derived from the QD and rhodamine. The results obtained indicate that modulation of the supra-molecular structure of polyrotaxane (DMAE-ss-PRX), a condenser that is cleaved in a reductive environment, conferred euchromatin-preferred decondensation. This represents the first demonstration of the successful control of condensation/decondensation in specific nuclear sub-domain via the use of an artificial DNA condenser.
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Affiliation(s)
- Sharif M Shaheen
- Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan
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15
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Sinkeldam RW, Greco NJ, Tor Y. Fluorescent analogs of biomolecular building blocks: design, properties, and applications. Chem Rev 2010; 110:2579-619. [PMID: 20205430 PMCID: PMC2868948 DOI: 10.1021/cr900301e] [Citation(s) in RCA: 658] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Renatus W. Sinkeldam
- Department of Chemistry and Biochemistry, University of California, San Diego 9500 Gilman Drive, La Jolla, California 92093-0358
| | | | - Yitzhak Tor
- Department of Chemistry and Biochemistry, University of California, San Diego 9500 Gilman Drive, La Jolla, California 92093-0358
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16
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Henriques A, Madeira C, Fevereiro M, Prazeres D, Aires-Barros M, Monteiro G. Effect of cationic liposomes/DNA charge ratio on gene expression and antibody response of a candidate DNA vaccine against Maedi Visna virus. Int J Pharm 2009; 377:92-8. [DOI: 10.1016/j.ijpharm.2009.05.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 04/30/2009] [Accepted: 05/06/2009] [Indexed: 10/20/2022]
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Kong HJ, Kim ES, Huang YC, Mooney DJ. Design of biodegradable hydrogel for the local and sustained delivery of angiogenic plasmid DNA. Pharm Res 2008; 25:1230-8. [PMID: 18183476 DOI: 10.1007/s11095-007-9526-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Accepted: 12/10/2007] [Indexed: 01/08/2023]
Abstract
PURPOSE To attain the effective local and sustained delivery of plasmid DNA (pDNA) encoding for a growth factor. METHODS We hypothesized that controlling the degradation rate of biomaterials encapsulating pDNA via concurrent physical dissociation of the cross-linked structure and hydrolytic chain breakage of polymers would allow one to significantly broaden the range of pDNA release rate. This hypothesis was examined using ionically cross-linked polysaccharide hydrogels which were previously designed to rapidly degrade via engineering of ionic cross-linking junction and partial oxidation of polysaccharide chains. RESULTS The hydrogel degradation rates were varied over the broad range, and pDNA release correlated with the gel degradation rate. Degradable hydrogels were used for the local and sustained delivery of a pDNA encoding for vascular endothelial growth factor (VEGF) in the ischemic hindlimbs of mice, and local pDNA release significantly improved the recovery of blood perfusion as compared with a bolus injection of VEGFencoding pDNA. CONCLUSION This strategy to control the hydrogel degradation rate may be useful in regulating the delivery of a broad array of macromolecular drugs, and subsequently improve their therapeutic efficacy.
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Affiliation(s)
- Hyun Joon Kong
- Division of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
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18
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Madeira C, Loura LMS, Prieto M, Fedorov A, Aires-Barros MR. Effect of ionic strength and presence of serum on lipoplexes structure monitorized by FRET. BMC Biotechnol 2008; 8:20. [PMID: 18302788 PMCID: PMC2275333 DOI: 10.1186/1472-6750-8-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Accepted: 02/26/2008] [Indexed: 11/28/2022] Open
Abstract
Background Serum and high ionic strength solutions constitute important barriers to cationic lipid-mediated intravenous gene transfer. Preparation or incubation of lipoplexes in these media results in alteration of their biophysical properties, generally leading to a decrease in transfection efficiency. Accurate quantification of these changes is of paramount importance for the success of lipoplex-mediated gene transfer in vivo. Results In this work, a novel time-resolved fluorescence resonance energy transfer (FRET) methodology was used to monitor lipoplex structural changes in the presence of phosphate-buffered saline solution (PBS) and fetal bovine serum. 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)/pDNA lipoplexes, prepared in high and low ionic strength solutions, are compared in terms of complexation efficiency. Lipoplexes prepared in PBS show lower complexation efficiencies when compared to lipoplexes prepared in low ionic strength buffer followed by addition of PBS. Moreover, when serum is added to the referred formulation no significant effect on the complexation efficiency was observed. In physiological saline solutions and serum, a multilamellar arrangement of the lipoplexes is maintained, with reduced spacing distances between the FRET probes, relative to those in low ionic strength medium. Conclusion The time-resolved FRET methodology described in this work allowed us to monitor stability and characterize quantitatively the structural changes (variations in interchromophore spacing distances and complexation efficiencies) undergone by DOTAP/DNA complexes in high ionic strength solutions and in presence of serum, as well as to determine the minimum amount of potentially cytotoxic cationic lipid necessary for complete coverage of DNA. This constitutes essential information regarding thoughtful design of future in vivo applications.
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Affiliation(s)
- Catarina Madeira
- 1IBB-Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Av. Rovisco Pais, 1049-001,Portugal.
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20
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Margineanu A, De Feyter S, Melnikov S, Marchand D, van Aerschot A, Herdewijn P, Habuchi S, De Schryver FC, Hofkens J. Complexation of lipofectamine and cholesterol-modified DNA sequences studied by single-molecule fluorescence techniques. Biomacromolecules 2007; 8:3382-92. [PMID: 17958438 DOI: 10.1021/bm700486q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lipoplex formation for normal and cholesterol-modified oligonucleotides is investigated by fluorescence correlation spectroscopy (FCS). To overcome the problems related to the fitting of autocorrelation curves when fluorescence bursts are present, the baseline fluorescence levels and the fluorescence bursts in the same trace were separately analyzed. This approach was not previously used in FCS studies of lipoplexes and allowed a more detailed characterization of this heterogeneous system. From the baseline levels, the number of free/bound DNA molecules and the presence of tens to hundreds of nanometer-sized lipoplexes were estimated using various mathematical models. Analysis of the fluorescent bursts provided an indication about the sizes of the lipoplexes, the number of DNA molecules in these aggregates, and the relative amount of lipids in each aggregate. An explanation for the higher transfection efficiency previously reported for one of the cholesterol-modified oligonucleotide compounds was found in relation to the formation of large size lipoplexes.
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Affiliation(s)
- Anca Margineanu
- Laboratory of Photochemistry and Spectroscopy, Catholic University of Leuven, Celestijnenlaan 200F, Leuven, Belgium
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21
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Abrunhosa F, Faria S, Gomes P, Tomaz I, Pessoa JC, Andreu D, Bastos M. Interaction and lipid-induced conformation of two cecropin-melittin hybrid peptides depend on peptide and membrane composition. J Phys Chem B 2007; 109:17311-9. [PMID: 16853210 DOI: 10.1021/jp051572e] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The interaction of two hybrid peptides of cecropin A and melittin [CA(1-8)M(1-18) and CA(1-7)M(2-9)] with liposomes was studied by differential scanning calorimetry (DSC), circular dichroism (CD), and quasi-elastic light scattering (QELS). The study was carried out with large unilamellar vesicles (LUVs) of three different lipid compositions: 1,2-dimyristoil-sn-glycero-3-phosphocholine (DMPC), 1,2-dimyristoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DMPG) and a binary mixture of DMPC/DMPG, in a wide range of peptide-to-lipid (P:L) molar ratios (0 to 1:7). DSC results indicate that, for both peptides, the interaction depends on membrane composition, with very different behavior for zwitterionic and anionic membranes. CD data show that, although the two peptides have different secondary structures in buffer (random coil for CA(1-7)M(2-9) and predominantly beta-sheet for CA(1-8)M(1-18)), they both adopt an alpha-helical structure in the presence of the membranes. Overall, results are compatible with a model involving a strong electrostatic surface interaction between the peptides and the negatively charged liposomes, which gives place to aggregation in the gel phase and precipitation after a threshold peptide concentration. In the case of zwitterionic membranes, a progressive surface coverage with peptide molecules destabilizes the membrane, eventually leading to membrane disruption. Moreover, delicate modulations in behavior were observed depending on the peptide.
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Affiliation(s)
- Filipa Abrunhosa
- CIQ (U.P.) Department of Chemistry, Faculty of Sciences, University of Porto, P-4169-007 Porto, Portugal
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22
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Madeira C, Loura LMS, Prieto M, Fedorov A, Aires-Barros MR. Liposome complexation efficiency monitored by FRET: effect of charge ratio, helper lipid and plasmid size. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 36:609-20. [PMID: 17262222 DOI: 10.1007/s00249-007-0130-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Revised: 12/21/2006] [Accepted: 01/02/2007] [Indexed: 12/01/2022]
Abstract
Cationic lipid/DNA complexes (lipoplexes) are promising vehicles for DNA vaccines or gene therapy. In these systems, transfection efficiency is highly related to lipoplex charge ratio, since lipoplexes with charge ratios (+/-) lower than electroneutrality have most DNA uncovered by the liposomes, and thus are unprotected from enzyme degradation. However, a large excess of cationic lipids is undesirable because of eventual cytotoxicity. The aim of this work was to determine the minimum charge ratio from which all DNA molecules are complexed by the liposomes varying the lipid formulation and plasmid size, using a new FRET (fluorescence resonance energy transfer) methodology. The similarity of FRET results, fluorescence intensity data and fluorescence decays of several charge ratios above (+/-) > or = 4 or 5 confirmed that once all DNA is covered by the liposomes, additional lipid molecules do not affect the lipoplex multilamellar repeat distance. It was also verified by FRET that the presence of helper lipid reduces the amount of cationic lipid required for DNA protection but does not affect the lipoplex multilamellar repeat distance. This distance varies with the plasmid size when supercoiled plasmid is used, being apparently larger when longer plasmids are used. Our study indicates that, despite the complexity of these systems not being totally described by our model, FRET is an informative technique in lipoplex characterization.
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Affiliation(s)
- Catarina Madeira
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Av Rovisco Pais, Portugal
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Breunig M, Lungwitz U, Liebl R, Goepferich A. Fluorescence resonance energy transfer: evaluation of the intracellular stability of polyplexes. Eur J Pharm Biopharm 2006; 63:156-65. [PMID: 16527471 DOI: 10.1016/j.ejpb.2006.01.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Revised: 12/21/2005] [Accepted: 01/27/2006] [Indexed: 10/24/2022]
Abstract
The investigation of intracellular mechanisms of non-viral nucleic acid delivery systems has provided great impetus for the improvement of their efficacy. Especially the intracellular release of the nucleic acid from the non-viral carrier system may be a relevant criterion for the high transfection efficiency of certain polymers. Therefore, we evaluated fluorescence resonance energy transfer (FRET) in combination with confocal laser scanning microscopy or flow cytometry as tool to determine the intracellular disintegration of polyplexes built with plasmid DNA and linear polyethylenimine. In microscopy, which allowed for an observation of polyplexes within single cells, sensitized emission measurement and acceptor photobleaching have been tested towards quantitative FRET analysis. In contrast, the whole cell population was analyzed by the flow cytometry-based method. We suggest that FRET is a useful tool to evaluate the intracellular disintegration of polyplexes built with various polymers.
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Affiliation(s)
- Miriam Breunig
- Department of Pharmaceutical Technology, University of Regensburg, Regensburg, Germany
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Chaltin P, Margineanu A, Marchand D, Van Aerschot A, Rozenski J, De Schryver F, Herrmann A, Müllen K, Juliano R, Fisher MH, Kang H, De Feyter S, Herdewijn P. Delivery of antisense oligonucleotides using cholesterol-modified sense dendrimers and cationic lipids. Bioconjug Chem 2005; 16:827-36. [PMID: 16029024 DOI: 10.1021/bc050022g] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cholesterol modified mono-, di-, and tetrameric oligonucleotides were synthesized and hybridized with antisense oligonucleotides to study their incorporation in cationic liposomes together with the influence of this dendrimeric delivery system on biological activity. Electrostatic interactions seem to play the most important role during complexation with cationic lipids. This oligonucleotide formulation gives a small but significant increase in the inhibition of P-glycoprotein expression in a cellular system.
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Affiliation(s)
- Patrick Chaltin
- Laboratory for Medicinal Chemistry, Rega Institute, Catholic University of Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium
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Kong HJ, Liu J, Riddle K, Matsumoto T, Leach K, Mooney DJ. Non-viral gene delivery regulated by stiffness of cell adhesion substrates. NATURE MATERIALS 2005; 4:460-4. [PMID: 15895097 DOI: 10.1038/nmat1392] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Accepted: 04/11/2005] [Indexed: 05/02/2023]
Abstract
Non-viral gene vectors are commonly used for gene therapy owing to safety concerns with viral vectors. However, non-viral vectors are plagued by low levels of gene transfection and cellular expression. Current efforts to improve the efficiency of non-viral gene delivery are focused on manipulations of the delivery vector, whereas the influence of the cellular environment in DNA uptake is often ignored. The mechanical properties (for example, rigidity) of the substrate to which a cell adheres have been found to mediate many aspects of cell function including proliferation, migration and differentiation, and this suggests that the mechanics of the adhesion substrate may regulate a cell's ability to uptake exogeneous signalling molecules. In this report, we present a critical role for the rigidity of the cell adhesion substrate on the level of gene transfer and expression. The mechanism relates to material control over cell proliferation, and was investigated using a fluorescent resonance energy transfer (FRET) technique. This study provides a new material-based control point for non-viral gene therapy.
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Affiliation(s)
- Hyun Joon Kong
- Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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Berezhna S, Schaefer S, Heintzmann R, Jahnz M, Boese G, Deniz A, Schwille P. New effects in polynucleotide release from cationic lipid carriers revealed by confocal imaging, fluorescence cross-correlation spectroscopy and single particle tracking. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1669:193-207. [PMID: 15893522 DOI: 10.1016/j.bbamem.2005.02.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Revised: 02/09/2005] [Accepted: 02/09/2005] [Indexed: 10/25/2022]
Abstract
We report on new insights into the mechanisms of short single and double stranded oligonucleotide release from cationic lipid complexes (lipoplexes), used in gene therapy. Specifically, we modeled endosomal membranes using giant unilamellar vesicles and investigated the roles of various individual cellular phospholipids in interaction with lipoplexes. Our approach uses a combination of confocal imaging, fluorescence cross-correlation spectroscopy and single particle tracking, revealing several new aspects of the release: (a) phosphatidylserine and phosphatidylethanolamine are equally active in disassembling lipoplexes, while phosphatidylcholine and sphingomyelin are inert; (b) in contrast to earlier findings, phosphatidylethanolamine alone, in the absence of anionic phosphatidylserine triggers extensive release; (c) a double-stranded DNA structure remains well preserved after release; (d) lipoplexes exhibited preferential binding to transient lipid domains, which appear at the onset of lipoplex attachment to originally uniform membranes and vanish after initiation of polynucleotide release. The latter effect is likely related to phosphatidyleserine redistribution in membranes due to lipoplex binding. Real time tracking of single DOTAP/DOPE and DOTAP/DOPC lipoplexes showed that both particles remained compact and associated with membranes up to 1-2 min before fusion, indicating that a more complex mechanism, different from suggested earlier rapid fusion, promotes more efficient transfection by DOTAP/DOPE complexes.
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Affiliation(s)
- Svitlana Berezhna
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen, Germany.
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Madeira C, Fedorov A, Aires-Barros MR, Prieto M, Loura LMS. Photophysical Behavior of a Dimeric Cyanine Dye (BOBO-1) Within Cationic Liposomes. Photochem Photobiol 2005; 81:1450-9. [PMID: 16029081 DOI: 10.1562/2005-03-16-ra-464] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This study is aimed at establishing optimal conditions for the use of 2,2'-[1,3-propanediylbis[(dimethyliminio)-3,1-propanediyl-1(4H)-pyridinyl-4-ylidenemethy-lidyne]]bis[3-methyl]-tetraiodide (BOBO-1) as a fluorescent probe in the characterization of lipid/DNA complexes (lipoplexes). The fluorescence spectra, anisotropy, fluorescence lifetimes and fluorescence quantum yields of this dimeric cyanine dye in plasmid DNA (2694 base pairs) with and without cationic liposomes (1,2-dioleoyl-3-trimethylammonium-propane [DOTAP]), are reported. The photophysical behavior of the dye in the absence of lipid was studied for several dye/DNA ratios using both supercoiled and relaxed plasmid. At dye/DNA ratios (d/b) below 0.01 the fluorescence intensity increases linearly, whereas lifetime and anisotropy values of the dye are constant (tau approximately 2.5 ns and <r> = 0.20). By agarose gel electrophoresis it was verified that up to d/b = 0.01 DNA conformation is not considerably modified, whereas for d/b = 0.05-0.06 a single heavy band appears on the gel. For these and higher dye/DNA ratios the fluorescence intensity, anisotropy and average lifetime values decrease with an increase in BOBO-1 concentration. When cationic liposomes are added to the BOBO-1/DNA complex, an additional effect is noticed: The difference in the environment probed by BOBO-1 bound to DNA leads to a decrease in quantum yield and average lifetime values, and a redshift is apparent in the emission spectrum. For fluorescence measurements including energy transfer (FRET), a d/b ratio of 0.01 seems to be adequate because no considerable change on DNA conformation is detected, a considerable fluorescent signal is still measured after lipoplex formation, and energy migration is not efficient.
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Affiliation(s)
- Catarina Madeira
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001, Portugal
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28
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Melik-Nubarov N, Krylova O. The Control of Membrane Properties by Synthetic Polymers. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s1554-4516(05)02005-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
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