Patent Application
20140004499
The invention relates to methods of localising biofunctional moieties (F) to surfaces and synthetic constructs of the general structure F-S-S′ (where S′ is a sterol) for use in such methods. In particular, the invention relates to the preparation of biofunctional surfaces and surface modified biological structures including cells (kodecytes), enveloped viruses (kodevirions) and liposomes or virosomes (kodesomes).
The ability to localise biofunctional moieties to solid surfaces and membranes has utility in both diagnostic and therapeutic applications. For example, immunosorbent based applications are dependent on the use of an insoluble preparation of an antigen (the biofunctional moiety) to bind specific antibodies from a mixture. Similarly, the publication of Spedden (2008) describes the identification and immobilization of glycosylated molecules having biomimetic properties on solid state surfaces and films or on membranes arising at the interface between non-polar and polar materials. The biomimetic glycosylated films and particles constructed therefrom are identified as having industrial, environmental, diagnostic and/or therapeutic utility in the binding, capture, and/or extraction of pathogens, toxins and/or contaminants, in vivo, in vitro or in situ.
The publication of Bovin et al (2005) describes the preparation of synthetic molecules that spontaneously and stably incorporate into lipid bilayers, including cell membranes. The synthetic molecules are used to effect qualitative and quantitative changes in the expression of cell surface antigens. Similarly, the publication of Korchagina et al (2008) describes the preparation and use of fluorescent cell markers of the structure F-S1-S2-L where F is a fluorophore, S1-S2 is a spacer linking F to L, and L is a diacyl lipid. The markers are used to localise the fluorophore (the biofunctional moiety) to the surface of cells and multi-cellular structures. In addition, the publications of Weinberg et al (2009) and Bovin et al (2009) describe the preparation of functional lipid constructs, including peptide-lipid constructs that are readily dispersible in aqueous media and have utility in diagnostic and therapeutic applications, including serodiagnosis.
It is an object of this invention to provide an alternative method of modifying surfaces by the localisation of biofunctional moieties. It is an object of this invention to provide an improved method of localizing functional moieties to artificial membranes, including liposomes. These objects are to be read disjunctively with the object of the invention to at least provide the public with a useful choice.
In a first aspect the invention provides a method of localizing a hydrophilic biofunctional moiety to a surface comprising the step of contacting the surface with an aqueous solution of a construct of the structure F-S-S′ where F is the biofunctional moiety, S is a spacer covalently linking F to S′, and S′ is sterol. S is selected to provide a construct that forms a stable, monophasic dispersion in water in the absence of detergents or organic solvents (water dispersible).
Preferably, F is selected from the group consisting of: biotin and O-linked oligosaccharides. Preferably, when the biofunctional moiety (F) is an oligosaccharide, the biofunctional moiety (F) is selected from the group consisting of: GalNAcα3(Fucα2)Galβ-; Galα3(Fucα2)Galβ-; GalNa3(Fucα2)Galβ-; Fucα2Galβ-; Galβ4GlcNAcβ3(Galβ4GlcNAcβ6)Galβ-; Galβ4GlcNAcβ3-; Galβ4Glcβ-; Galβ3GlcNAcβ-; Galβ3(Fucα4)GlcNA4-; Fucα2Galβ3(Fucα4)GlcNAcβ-; GalNAcα3(Fucα2)Galβ3(Fucα4)GlcNAcβ-Galα3(Fucα2)Galβ3(Fucα4)GlcNAcβ-; Galβ4(Fucα3)GlcNAcβ-; Fucα2Galβ4(Fucα3)GlcNAcβ-; NeuAcα2-3 Galβ3(Fucα4)GlcNA4-; NeuAcα2-3Galβ4(Fucα3)GlcNA0-; GalNAcβ4(NeuAcα2-3)Galβ4-; Galβ3GalNAcα-; NeuAcα2-3Galβ4-; NeuAcα2-6Galβ4-; Galα4Galβ4-; GalNAcβ3Galα4Galβ4-; Galα4Galβ4GlcNAcβ3-; Galβ3GalNAcβ3Galα4-; NeuAcα2-3Galβ3GalNAcβ3Galα4-; Galα3Galβ-; GalNAcα3GalNAcβ3Galα4-; GalNAcβ3GalNAcβ3Galα4-; Galβ1-4GlcNAc; Galβ1-3GlcNAc; SAα2-6Galβ1-4Glc; SAα2-3Galβ1-4Glc; SAα2-6Galβ1-4GlcNAc; SAα2-3Galβ1-4GlcNAc; SAα2-3Galβ1-3GlcNAc; Galβ1-4(Fucα1-3)GlcNAc; Galβ1-3(Fucα1-3)GlcNAc; SAα2-3Galβ1-3(Fucα1-4)GlcNAc; SAα2-3Galβ1-4(Fucal-3)GlcNAc; Galβ1-4GlcNAcβ1-4GlcNAc; Galβ1-3GlcNAcβ1-4GlcNAc; SAα2-6Galβ1-4GlcNAcβ1-4GlcNAc; SAα2-3Galβ1-4GlcNAcβ1-4GlcNAc; SAα2-3Galβ1-3GlcNA41-4GlcNAc; Galβ1-4(Fucα1-3)GlcNAcβ1-4GlcNAc; Galβ1-3(Fucα1-4)GlcNAcβ1-4GlcNAc; SAα2-3Galβ1-3(Fucα1-4)GlcNAcβ1-4GlcNAc; SAα2-3Galβ1-4(Fucα1-3)GlcNA41-4GlcNAc; SAα2-3Galβ1-3(Fucα1-4)GlcNAcβ1-4Gal; SAα2-3Galβ1-4(Fucα1-3)GlcNAβ1-4Gal; SAα2-3Galβ1-4GlcNAβ1-3Galβ1-4(Fucα1-3)GlcNAc; SAα2-6Galβ1-4GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAc; SAα2-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4Glc; SAα2-6Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4Glc; SAα2-3Galβ1-4GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4Glc; SAα2-6Galβ1-4GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4Glc; SAα2-3Galβ1-4(Fucal-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4Glc; SAα2-6Galβ1-4(Fucal-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4Glc; SAα2-3Galβ1-4(Fucal-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-6Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-3Galβ1-4GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-6Galβ1-4GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-6Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4(Fucal-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-3Galβ1-3(Fucα1-4)GlcNAc; SAα2-6Galβ1-3(Fucα1-4(GlcNAc; SAα2-3Galβ1-3GlcNAcβ1-4Galβ1-4(Fucα1-3)GlcNAc; SAα2-6Galβ1-3GlcNAcβ1-4Galβ1-4(Fucα1-3)GlcNAc; SAα2-3Galβ1-3(Fucal-4)GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAc; SAα2-6Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAc; SAα2-3Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4Glc; SAα2-6Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4Glc; SAα2-3Galβ1-3GlcNAβ1-4Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4Glc; SAα2-6Galβ1-3GlcNAβ1-4Galβ1-4(Fucα1-3)GlcNAβ1-3Galβ1-4Glc; SAβ2-3Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4Glc; SAα2-6Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4Glc; SAα2-3Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-6Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-3Galβ1-3GlcNAcβ1-4Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-6Galβ1-3GlcNAcβ1-4Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-3Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-6Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-3Galβ1-4GlcNAcβ1-3Galβ1-3(Fucα1-4)GlcNAc; SAα2-6Galβ1-4GlcNAcβ1-3Galβ1-3(Fucα1-4)GlcNAc; SAα2-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-3(Fucα1-4)GlcNAc; SAα2-6Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-3(Fucα1-4)GlcNAc; SAα2-3Galβ1-4GlcNAcβ1-3Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4Glc; SAα2-6Galβ1-4GlcNAcβ1-3Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4Glc; SAα2-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4Glc; SAα2-6Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4Glc; SAα2-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-3(Fucα1-4)Glc; SAα2-6Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-3(Fucα1-4)Glc; SAα2-3Galβ1-4GlcNAcβ1-3Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-6Galβ1-4GlcNAcβ1-3Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc; SAα2-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4(Fucα1-3) Glc; and SAα2-6Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-3(Fucα1-4)GlcNAcβ1-3Galβ1-4(Fucα1-3)Glc, where SA is sialic acid.
Preferably, S′ is selected from the group consisting of planar sterols. More preferably, S′ is selected from the group consisting of: campesterol, cholesterol, ergosterol, sitosterol and stigmasterol. Most preferably, S′ is cholesterol.
In a first preferment of the first aspect of the invention the water dispersible construct is of the structure:
where a is the integer 2, 3 or 4.
In a second preferment of the first aspect of the invention the water dispersible construct is of the structure:
where a is the integer 2, 3 or 4 and b is the integer 3, 4 or 5.
In a third preferment of the first aspect of the invention the water dispersible construct is of the structure:
where a is the integer 2, 3 or 4, b is the integer 3, 4 or 5, c is the integer 1, 2 or 3, d is the integer 3, 4 or 5, e is the integer 1, 2 or 3 and M is a monovalent cation.
In an embodiment of the first preferment of the first aspect of the invention the water dispersible construct is of the structure:
designated Atri-S1-chol (I).
In an embodiment of the second preferment of the first aspect of the invention the water dispersible construct is of the structure:
designated Atri-S1-S2-chol (II).
In an embodiment of the third preferment of the first aspect of the invention the water dispersible construct is of the structure:
where b is 4, c is 2, d is 4, e is 2, M is sodium ion (Na+) and designated Biotin-S3-S4-S2-chol (III).
In a fourth preferment of the first aspect of the invention, the surface is the membrane of a cell. Typically, the contacting is with a suspension of cells.
In a fifth preferment of the first aspect of the invention, the surface is the membrane of an enveloped virus. Typically, the contacting is with a suspension of enveloped viruses.
In a sixth preferment of the first aspect of the invention, the surface is the lipid bilayer of a liposome or virosome. Typically, the contacting is with a dispersion of the liposomes or virosomes.
The step of contacting the surface with an aqueous solution of a water dispersible construct may be by propelling droplets of the aqueous solution from a plurality of orifices located in a monolithic print head of an inkjet printer onto at least one discrete area on the surface.
Preferably, the volume of each of the droplets is 1 to 100 picolitres (pL). More preferably, the volume of each of the droplets is 1 to 50 pL. Most preferably, the volume of each of the droplets is 1 to 5 pL.
Preferably, the concentration of the water dispersible construct in the aqueous solution is 1 μmolar (μM) to 10 mmolar (mM). More preferably, the concentration of the construct in the aqueous solution is 10 μM to 10 mM. Most preferably, the concentration of the construct in the aqueous solution is 0.1 to 10 mM.
In a first preferment of the step of contacting the surface with an aqueous solution, the at least one discrete area is in the shape of a symbol. Preferably, the at least one discrete area is in the shape of a symbol readable by optical character recognition (OCR) apparatus. More preferably, the at least one discrete area is in the shape of a symbol comprising one or more alphanumeric characters. In a second preferment of the step of contacting the surface with an aqueous solution, the at least one discrete area is a pattern comprising a combination of indicia to which the aqueous solution is applied at different densities (amount per unit area). The first and second preferments are not mutually exclusive.
Methods including the step of contacting a surface with an aqueous solution of a water dispersible construct by propelling droplets of a aqueous solution from a plurality of orifices located in a monolithic print head of an inkjet printer onto at least one discrete area on a surface are described in the specification accompanying international application no. PCT/NZ2010/000127 (publ. no WO 2011/002310) (Bovin et al (2011)).
In a second aspect the invention provides an aqueous solution of a water dispersible construct of the structure:
where F is a biofunctional moiety, S′ is sterol, and a is the integer 2, 3 or 4.
In an embodiment of the second aspect of the invention the water dispersible construct is of the structure:
designated Atri-S1-chol (I).
In a third aspect the invention provides an aqueous solution of a water dispersible construct of the structure:
where F is a biofunctional moiety, S′ is sterol, a is the integer 2, 3 or 4 and b is the integer 3, 4 or 5.
In an embodiment of the third aspect of the invention the water dispersible construct is of the structure:
designated Atri-S1-S2-chol (II).
In a fourth aspect the invention provides an aqueous solution of a water dispersible construct of the structure:
where F is a biofunctional moiety, S′ is sterol, a is the integer 2, 3 or 4, b is the integer 3, 4 or 5, c is the integer 1, 2 or 3, d is the integer 3, 4 or 5, e is the integer 1, 2 or 3 and M is a monovalent cation.
In an embodiment of the fourth aspect of the invention the water dispersible construct is of the structure:
where b is 4, c is 2, d is 4, e is 2, M is sodium ion (Na+) and designated Biotin-S3-S4-S2-chol (III).
In a fifth aspect the invention provides a cell incorporating in its membrane a water dispersible construct as defined in the second, third or fourth aspects of the invention.
In a sixth aspect the invention provides an enveloped virus incorporating in its membrane a water dispersible construct as defined in the second, third or fourth aspects of the invention.
In a seventh aspect the invention provides a liposome or virosome incorporating in its lipid bilayer a water dispersible construct as defined in the second, third or fourth aspects of the invention.
In an eighth aspect the invention provides a biofunctionalized surface incorporating a water dispersible construct as defined in the second, third or fourth aspects of the invention.
In the description, claims and representations of this specification the following acronyms, symbols, terms and phrases have the meaning provided:
“Aqueous solution” means a stable, monophasic dispersion prepared in water without the use of detergents or organic solvents at a temperature of 25° C.
“Biofunctional” means capable of participating in an interaction with one or more biomolecules in vitro or in vivo and “biofunctionalized” has a corresponding meaning. The term “biofunctional” specifically excludes covalent bond forming chemically reactive functional groups (e.g. thiols) and reporter groups (e.g. photophores).
“Biosurface engineering” means the modification of a surface by the localisation of biofunctional moieties.
“Detergent” means a substance which has the effect of altering the interfacial tension of water and other liquids or solids, but excludes the constructs of the generic structure F-S-S′ as defined herein.
“Differential expression” means the expression of the same moieties at a surface in different conformations.
“Differential localisation” means the localisation of the same or different moieties to a surface with different dissociation constants.
“Kodecyte” means a cell modified by incorporation into the cell membrane of a construct of the general structure F-S-L (where F is a functional moiety, S is a spacer selected to provide a water dispersible construct and L is a lipid).
“Kodesome” means a liposome or virosome modified by incorporation into the lipid bilayer (membrane) of a construct of the general structure F—S-L (where F is a functional moiety, S is a spacer selected to provide a water dispersible construct and L is a lipid).
“Kodevirion” means an enveloped virus particle modified by incorporation into the enveloping membrane of a construct of the general structure F-S-L (where F is a functional moiety, S is a spacer selected to provide a water dispersible construct and L is a lipid).
“Localised” means associated with a surface by non-covalent interactions and “localising” and “localisation” have a corresponding meaning.
“Monovalent cation (M)” means a counter ion having a positive charge of one (+1).
“Oligosaccharide” means a saccharide containing two or more monosaccharide units, typically two to ten monosaccharide units.
“( )x”, “( )x”, “[ ]x” and “[ ]x” mean the group contained in the parentheses is repeated a number (x) of times. By way of illustration:
means the methylene group (—CH2—) is repeated 4 times and the structure represented is equivalent to:
It will be understood that where the terms used to define F, S and S′ refer to molecules, the corresponding radical is comprised in the amphipathic construct (F-S-S′). For example, where the term “cholesterol” is used to define S′ it will be understood that the radical cholesteryl is comprised in the amphipathic construct F-S-S′. Unless otherwise stated S is a spacer covalently linking F to S′ via the 3β-hydroxyl position of sterol (5′).
It will also be understood that that where reference is made to a step of contacting a surface with an aqueous solution of a water dispersible construct the surface is pre-formed. The contacting is for a time and at a temperature sufficient (typically 1 to 24 hours and 4 to 37° C., respectively) to achieve the localisation. The methods of localizing a biofunctional moiety to a surface including this step are to be distinguished from methods of incorporating a construct into the lipid bilayer (membrane) of a liposome or virosome by mixing an amount of construct with other components of the bilayer before preparing the liposomes or virosomes.
The terms “first”, “second”, “third”, etc. used with reference to elements, features or integers of the subject matter defined in the Statement of Invention and Claims, or when used with reference to alternative embodiments of the invention are not intended to imply an order of preference.
The invention will now be described with reference to embodiments or examples and the figures of the accompanying drawings pages.
The invention uses constructs of the generic structure F-S-S′ where S′ is a sterol. These water dispersible constructs are readily dispersible in water and may be used in conjunction with their diacyl or dialkyl counterparts (as described in the publications of Bovin et al (2005), Korchagina et al (2008), Bovin et al (2009) and Weinberg et al (2009)) to provide biofunctionalized surfaces and surface modified biological structures with novel characteristics. Where the surface is a lipid bilayer (membrane), such as the surface of a liposome or virosome, the sterol (S′) of the construct has the potential to stabilise and improve the structural integrity of the membrane. The amphipathic constructs may therefore be used advantageously in the preparation of such vehicles and biomimetic films such as those described in the publication of Spedden (2008).
Water soluble constructs of the generic structure F-S-L where L is a phospholipid are described in the publications of Bovin et al (2005), Korchagina et al (2008), Bovin et al (2009) and Weinberg et al (2009). The primary amino (NH2—) function of phosphatidylethanolamine provides a convenient means by which functional moieties (F) can be conjugated to the lipid (L) via an appropriate spacer (S). Methods of conjugating specific functional moieties to sterol are described in the publications of Barragan et al (2001), Boonyarattanakalin et al (2006), Booth et al (2001), Carrion et al (2001), DUffels et al (2000), Orr et al (1979), Pacuszka et al (1991), Spencer et al (2004), Vidal et al (2003) and others.
The publication of Barragan et al (2001) describes the synthesis of mannose-6-phosphonate-cholesterylamine conjugates via 3-aminocholesterol. The publication of Booth et al (2001) discloses the synthesis of biotinylated cholesteryl derivatives. The publication of Carrion et al (2001) discloses the preparation of poly(ethylene glycol)-coated liposomes using pegylated cholesterol derivatives linked either directly or through a spacer arm of diaminebutane via a carbamate bond. The publication of Duffels et al (2000) discloses the synthesis of high mannonse type cholesterol-based neoglycolipids. The publication of Orr et al (1979) describes the preparation of synthetic mannose-containing glycolipids utilising the cholesterol nucleus as a lipid anchor and either a 6-aminohexyl- or a 6-(6-aminohexanamido) hexyl-1-thio-α-D-mannopyranoside as a carbohydrate ligand. The publication of Pacuszka et al (1991) discloses the synthesis of several lipid analogues of ganglioside GM1 including an analog prepared by attaching the oligosaccharide moiety of the ganglioside to cholesteryl hemisuccinate.
The water soluble constructs used in the present invention are prepared via cholesterol chloroformate. The poor dispersibility of sterol chloroformate (relative to phosphatidyl ethanolamine, e.g. DOPE) in solvents compatible with the dissolution of very hydrophilic derivatives of functional moieties such as biotin-S3-S4 and Atri-S1 results in negligible yield of water soluble construct. This incompatibility, arising from the hydrophilicity of the derivative of the functional moiety and hydrophobicity of the sterol derivative and the resulting heterogeneous reaction mixture, presents a technical obstacle to the facile synthesis of the water soluble constructs. The use of a steroylcarbonylaminoalkanoic acid Nos-succinimide esters, such as that prepared according to Scheme I, in the preparation of water soluble constructs, such as that prepared according to Scheme IV, has been found to be advantageous in promoting yields where the derivative of the functional moiety is particularly hydrophilic.
In the publication of Pacuszka et al (1991) although the oligosaccharide moiety provided the recognition site for the binding of cholera toxin, the nature of the lipid moiety played an important role in the action of the toxin. More recently, the publication of Lingwood et al (2011) has stated that membrane cholesterol induces a tilt in glycolipid receptor headgroups, resulting in loss of access for ligand binding. The collective behaviour of lipids is documented as a dimension of surface recognition and communication. It is suggested that lipid “allostery” can be a means to regulate membrane recognition processes. Membrane cholesterol is identified as a key molecule in the regulation of glycolipid confirmation and receptor function. The publication of Spencer et al (2004) suggested an unexpected tolerance of biological membranes regarding the incorporation of sterols of differing chemical structure based on studies using a number of benzophenone-containing cholesterol analogues notably, the analogues in which the 3β-hydroxyl group had been replaced with a large amidobenzophenone group were capable of replacing up to 50% of cellular free cholesterol.
In the publication of Duffels et al (2000) the neoglycolipids are proposed for use as additives to cationic liposome formulations in the active targeting of liposomes to macrophages. The publication of Zurbriggen et al (2006) describes a method for the effective lyophilization and reconstitution of fusion-active vehicles, namely virosomes. The virosomes prepared by the method are presented as being particularly useful to deliver biologically active substances, including antigens, drugs and other pharmaceutically active substances including DNA, RNA or siRNA into cells. The method utilises cationic lipids, specifically cationic cholesteryl derivatives. The virosomal membrane compositions comprise preferably between 1.9 and 37 mol % 3β[N—(N′,N′-dimethylammonioethane)-carbamoyl]cholesterol chloride (DC-Chol) or 3β[N—(N′,N′N′-trimethylammonioethane)-carbamoyl]cholesterol chloride (TC-Chol), the residual lipid content of the membrane consisting preferably of phospholipids.
It is recognised that the method of the present invention may be employed in conjunction with methods of preparing and/or reconstituting fusion-active vehicles, such as virosomes. In the methods described by Zurbriggen et al (2006) the functional viral envelope glycoproteins hemagglutinin (HA) and neuraminidase (NA) intercalated in the phospholipid by-layer are proposed as imparting structural stability and homogeneity to the virosomal formulations. In the method of the present invention the water dispersible constructs per se are anticipated to import such structural stability. The use of potentially destabilising organic solvents or detergents, such as octaethyleneglycol-mono-(n-dodecyl)ether (OEG), is inconsistent with realising this advantage.
It is also anticipated that the constructs used in the method of the present invention will preferentially partition into lipid rafts when incorporated into cell membranes. This preferential partitioning may be utilised to promote endocytosis or viral infection by the concentration of appropriate biofunctional moieties (ligands).
To a solution of cholesteryl chloroformate (16.8 mg, 0.0375 mmol) in dry dichloromethane (1 ml) was added Atri-S1-NH2 (20 mg, 0,034 mmol) in DMF (0.5 ml) and triethylamine (5 μL). The mixture was incubated for 1 hour at room temperature followed by column chromatography (Sephadex LH-20, 1:1 (v/v) chloroform-methanol) of the mixture to yield I (80%).
To a solution of cholesteroylcarbonylaminopentanoic acid (S2-S′) (7.9 mg, 14.9 mkM) in DMF (0.3 mL), DSC (3.8 mg, 14.8 μM) and triethylamine Et3N (2 μL, 14.4 μM) were added. The solution was stirred for 2 hours to provide a solution of cholesteroyl carbonylaminopentanoic acid Nos-succinimide ester (Nos-S2-S′).
To a solution of Nos-S2-S′ (25 mg, 0.04 mmol) in dry N,N-dimethylformamide (1 ml) was added Atri-S1-NH2 (21.1 mg, 0.036 mmol) in DMF (1 ml) and triethylamine (20 μl) was added. The mixture was kept for 1 hour at room temperature followed by column chromatography (Sephadex LH-20, 1:1 (v/v) chloroform-methanol) of the mixture to yield II (78%).
To a solution of cholesteroylcarbonylaminopentanoic acid Nos-succinimide ester (Nos-S2-S′) was added a solution of biot-S3-S4-NH2 (9.1 mg, 7.17 μM) in isopropanol/H2O (1:1 (v/v), 1 mL). The heterogeneous mixture was stirred for 15 hours before being evaporated and the residue separated on a silica gel column (15 mL) eluted with CHCl3/MeOH (5:1 (v/v)). The target Biotin-S3-S4-S2-chol (III) was eluted with CHCl3/MeOH/H2O (6:3:1 (v/v/v)). The yield of biotin-S3-S4-S2-chol (III) was 2 mg (15.5% calculated on the basis of biot-S3-S4-NH2).
1H NMR (700 MHz, [D2]H2O/[D4]CH3OH 1:2, 30° C.): 5.575 (d, J=3.6 Hz 1H; ═CH of cholesterol), 4.737 (dd, J=7.8 Hz, J=5 Hz, 1H; NHCH of biotin), 4.553 (dd, J=7.8 Hz, J=4.3 Hz, 1H; NHCH of biotin), 4.534 (m, 1H; OCH of cholesterol), 4.470-4.078 (total 32H; 4 CH2COO, 12 NCH2CO), 3.540 (m, 4H; NHCH2CH2NH), 3.446 (m, 1H; NHCHCH of biotin), 3.290 (t, J=6.7 Hz, 2H; CH2N of aminovaleric res.), 3.149 (dd, J=13 Hz, J=5 Hz, 1H; NHCHCH of biotin), 2.916 (dd, J=13 Hz, J<2 Hz, 1H; NHCHCH of biotin), 2.515 (m, 6H; 2 CH2CO and ═CH—CH2 of cholesterol), 2.208-1.105 (total 39H; 29H of cholesterol, 4H of aminovaleric res. and 6H of biotin), 1.105 (d, J=6.6 Hz, 3H; CH3CH of cholesterol), 1.050 and 1.046 (2 d, J=6.6 Hz, 2×3H; 2 CH3CH of cholesterol), 0.878 (s, 3H; CH3 of cholesterol) ppm.
The structures of Atri-S1-chol (I) and Atri-S1-S2-chol (II) are to be contrasted with the structure of the construct designated Atri-S1-S5-DOPE as described in the publication of Bovin et al (2005). The differential localisation of these constructs was demonstrated by printing on artificial surfaces.
An ink jet printer (EPSON STYLUS™ T21) with refillable cartridges modified to hold a smaller volume was employed. The constructs were prepared as solutions at a concentration of circa 6 mM. Each one of the solutions was used to fill separate modified cartridges permitting both solutions to be printed at the same time on the same sample of paper. To facilitate identification the identification of the solution and artificial surface were printed. Following printing of the two solutions each sample of artificial surface was blocked with a 2% (w/v) solution of BSA and immunostained with monoclonal anti-A and then anti-mouse IgG conjugated to alkaline phosphatase and the chromogenic substrate NBT-BCIP. The immunostained samples of printed paper are presented in
A second trial was performed employing the same methodology, but using constructs (F-S-L and F-S-S′) where the biofunctional moiety (F) of the constructs was biotin. In addition, nitrocellulose was included as an artificial substrate. As in the first trial the identification of the construct in the solution and the artificial surface were printed. On this occasion visualisation of the printed construct was achieved by conjugation with streptavidin-alkaline phosphatase conjugate (Sigma). Solutions of the construct designated Biotin-S3-S4-S2-chol (III) (“FSS-Biotin”) and the construct designated Biotin-S3-S4-S5-DOPE (IV) (“FSL-Biotin”) were prepared at concentrations of 5 mM, 25 mM and 100 mM in PBS containing 0.01% v/v TWEENI™ 20 and 1% magenta ink. Following printing the printed artificial surfaces were blocked with 2% (w/v) BSA in PBS for 60 minutes at room temperatures. The printed artificial surfaces was then washed by flooding the surface six times with PBS for 20 seconds each washing step. The surface of the washed artificial substrate was then flooded with a solution of 2 μg/mL of the streptavidin-alkaline phosphatase conjugate and incubated at room temperature for 30 minutes before washing with the substrate buffer (pH 9.5) containing 100 mM Tris, 100 mM sodium chloride and 50 mM magnesium chloride. Following washing with the substrate buffer the surface of the artificial substrate was flooded with a 50-fold dilution in PBS of 18.75 mg/mL nitro blue tetrazolium chloride and 9.4 mg/mL 5-bromo-4-chloro-3-indolyl phosphate, toluidine salt in 67% dimethyl sulfoxide (DMSO) (Roche).
The artificial substrate was incubated at room temperature for 5 minutes before washing the surface with deionised water to stop the chromogenic reaction. The results are presented in
The use of aqueous solutions of the construct designated Biotin-S3-S4-S2-chol (III) and the construct designated Biotin-S3-S4-S5-DOPE (IV) in the localisation of biotin (F) to cell surfaces was also compared. Solutions of the two constructs were prepared at substantially equimolar concentrations. The use of the solutions was assessed across a concentration range from 0 to 500 μM (0.5 mM). A 0.5 mM solution of the construct designated Biotin-S3-S4-S2-chol (III) was prepared by dissolving 0.4 mg of the construct in 514 μL of PBS. The construct readily dissolved to provide a clear solution. A 0.5 mM stock solution of the construct designated Biotin-S3-S4-S5-DOPE (IV) was prepared by dissolving 2 mg of the construct in 1942 μL of phosphate buffered saline (PBS). Each 0.5 mM solution was warmed to 37° C. for 10 minutes, vortexed and sonicated for 30 seconds to ensure complete dissolution of the construct in the aqueous medium. A dilution series was prepared for each construct to provide a total volume of 100 μL at each of the following concentrations: 5, 10, 25, 50, 75, 100 and 500 LM. Equal volumes (40 μL) of packed, washed red blood cells (RBCs) and solutions of constructs at different concentrations were mixed in a glass kimble tube. The tubes were incubated at 37° C. for 20 minutes in a water bath with periodic (3 x) agitation. The incubated cells were washed 3× with PBS before being resuspended in a cell preservative (CELPRESOL™) for storage at 4° C. overnight.
Two equal volumes were taken from each tube and centrifuged (300×g for 2 minutes) to provide two equivalent packed cells volumes for further evaluation. One of each pair of equivalent packed cell volumes was evaluated for localisation of the biofunctional moiety biotin to the surface of the RBCs by conjugation with avidin ALEXAFLUOR™. One of each pair of the equivalent packed cell volumes was evaluated for localisation of the biofunctional moiety biotin to the surface of the RBCs by conjugation to avidinylated beads (DYNABEADS™ M-280).
Conjugation with avidin ALEXAFLUOR™ was evaluated as described in the publication of Oliver et al (2011). An aliquot containing 0.02 mg avidin ALEXAFLUOR™ was mixed with a volume (190 μL) of PBS containing BSA to provide a 0.1 mg/mL solution. Equal volumes 20 μL of packed RBCs and the solution of avidin ALEXAFLUOR™ were mixed and incubated at 37° C. for 30 minutes. The cells were then washed 3× with PBS before placing a drop (10 μL) on a glass microscope slide for fluorescent microscopy (WIB filter at 400× magnification). Cells were graded for fluorescence intensity over two micrograph fields of view. Grades determined via the eye piece were correlated with the corresponding photomicrographs (1.9 sec exposure). Grades were assigned according to the following scale: 1 (low), 2 (moderate), 3 (bright) and 4 (very bright). The morphology of the cells was also recorded (“normal” or “poiked”).
Conjugation with avidinylated beads (DYNABEADS™ M-280) was performed. An aliquot of a volume (100 μL) of beads (1 μm diameter, 12×109 beads per mL) was washed 3× in sterile PBS for one minute at 1000×g. The concentration of the beads was adjusted to 6×109 beads/mL with 100 μL PBS and a volume (5 μL) mixed with an equal volume of a 1% dilution of packed RBCs (circa 7.5×107 cells/mL) directly on a microscope slide. The ratio of beads to cells was approximately 600. This ratio of beads to cells was easily mixed by drawing the volume in and out of the pipette tip before overlaying a coverslip. The attachment of beads to cells was scored at 400× and 800× magnification on a compound microscope. An estimate of the number of beads and the presence of cell clusters was recorded for each group and compared with a negative control.
The fluorescent intensity determined for cells prepared using either the construct designated Biotin-S3-S4-S5-DOPE (IV) or the construct designated Biotin-S3-S4-S2-chol (III) was generally similar. The use of the construct designated Biotin-S3-S4-S2-chol (III) at lower concentration ranges (5 to 75 μM) provided moderately lower fluorescent signal intensity relative to cells prepared using the construct designated Biotin-S3-S4-S5-DOPE (IV) over the same concentration range. However, cells prepared using the construct designated Biotin-S3-S4-S2-chol (III) appeared to show a more homogenous modification over the entire cell surface and lesser inter-cell variation. This may indicated that the modification of cells with the construct designated Biotin-S3-S4-S2-chol (III) is less influenced by intra and inter-cell variation in the composition of the cell membrane. Both of the constructs were observed to show poor staining at the higher concentrations of 100 and 500 μM with both intra and inter-cell variation. The use of the constructs at concentrations of 10 and 25 μM appeared to provide the most consistent and uniform modification with a fluorescent signal intensity of grade 2. The use of the construct designated Biotin-S3-S4-S5-DOPE (IV) and the construct designated [FSS-Biotin]produced comparable results when evaluated by attachment of avidinylated beads (DYNABEADS™ M-280).
The attachment of beads was observed to be optimal when 25 μM concentrations of the two constructs were used. At this concentration 4 to 8 beads were observed to be attached to each RBC along with clustering of RBCs in groups of 8 or more cells. The number of beads attached to each RBC and the clustering of RBCs into groups was observed to be slightly greater where these cells were prepared using the construct designated Biotin-S3-S4-S2-chol (III). Similarly, optimum results were obtained when concentrations of the constructs in the range 10 to 25 μM were used. This suggests that the uniformity of modification of the cells surface is a more significant determinant when evaluating bead attachment than level of modification (cf. fluorescent signal intensity). A reduced level of attachment and the absence of clustering was observed when the constructs were used at concentrations of 100 and 500 μM. It is suggested that at these higher concentrations the association of the constructs with the surface of the cells is in the form of micelles rather than by insertion into the outer cell membrane. It is concluded that both constructs may be used optimally at concentrations in the range 10 to 50 μM.
The use of aqueous solutions of the construct designated Atri-S1-chol (I), the construct designated Atri-S1-S5-DOPE (V) and the construct designated Atri-S1-S5-S4-S5-DOPE (VI) in the localisation of Atri (F) to cell surfaces was also compared. (The constructs designated Atri-S1-S5-DOPE (V) and Atri-S3-S4-S5-DOPE (VI) (
Although the invention has been described with reference to embodiments or examples it should be appreciated that variations and modifications may be made to these embodiments or examples without departing from the scope of the invention. Where known equivalents exist to specific elements, features or integers, such equivalents are incorporated as if specifically referred to in this specification. In particular, variations and modifications to the embodiments or examples that include elements, features or integers disclosed in and selected from the referenced publications are within the scope of the invention unless specifically disclaimed. The advantages provided by the invention and discussed in the description may be provided in the alternative or in combination in these different embodiments of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 590342 | Jan 2011 | NZ | national |
| 596147 | Nov 2011 | NZ | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/NZ2012/000001 | 1/6/2012 | WO | 00 | 9/19/2013 |
