D depicts modification of the liposome with targeting peptides. Targeting peptide or antibody can be conjugated to functional PEG via chemical binding.
E shows low magnification of particles. Imaged using Tecnai TEM. Negative staining done by uranyl acetate. Scale bar indicates nm. F shows high magnification of particles show cloudy liposomal coating around dark and dense porous silicon- based core.
H shows a schematic of a particle of the disclosure. A-F Confocal microscopy of JA. Inset shows pinocytotic uptake of particles. Scale bar indicates nm; and I Fusogenic liposome-coated particles localized in cell cytoplasm. B Average days of survival of mice post-infection at day 0 and post- therapeutic injection at day 1.
Error bar indicates standard deviation. A PBS vs. F-pSi loaded with calcein without targeting peptide. C PBS vs. F-pSi loaded with calcein and conjugated to MTP. D-K unstained healthy or infected lung histology sections imaged for fluorescence detection of Dil-loaded particles. Thus, for example, reference to "a pore" includes a plurality of such pores and reference to "the antigen" includes reference to one or more antigens known to those skilled in the art, and so forth.
Similarly, "comprise," "comprises," "comprising" "include," "includes," and "including" are interchangeable and not intended to be limiting. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices and materials are described herein.
Nothing herein is to be construed as an admission that the inventors are not entitled to antedate such disclosure by virtue of prior disclosure. The porous nanostructures can hold therapeutics, diagnostic agents, or other beneficial substances sometimes referred to herein as "payloads".
However, premature release of these payloads, either prior to or post-administration, can be undesirable for the intended purpose. Additionally, the degradation of porous silicon or porous silicon oxide in aqueous conditions at sites other than the target site has posed a significant problem for sustained drug delivery, in vivo or in vitro imaging, and biosensor applications, which can benefit from protective coating around the porous silicon core. The reason for such continuous investment in liposomal formulations is attributed to their major advantages: biocompatibility, ease of synthesis, and surface modiflability.
Moreover, liposomes are known and recognized in the art  The disclosure provides a biodegradable liposomal porous silicon pSi nanoparticle system that can bypass endocytic uptake via liposome-plasma membrane fusion see, e. Membrane fusion allows a direct release of hydrophilic payloads from the core of liposomes into the cell cytoplasm, as well as a transfer of hydrophobic molecules from the liposomal bilayer to the cell membrane bilayer.
In addition, the liposomal porous silicon nanoparticle system allows a transfer of moieties conjugated on the outer surface of liposomes antibodies, small molecules, peptides, etc. The porous silicon core has photoluminescence properties that allows for these particles to be used as a tracking tool using time-gated luminescence imaging. Moreover, the porous silicon allows for condensation of the highly anionic genetic material into small clusters, allowing liposomes to easily encapsulate the particle and any payloads contained in the pores of the particle.
The disclosure demonstrates that fusogenic liposomal-coated pSi particles fuse with the membrane of cells and transfer various payloads into the cell. For example, the disclosure demonstrates that the fusogenic liposomal-coated pSi particles successfully fuse with Neuro2a mouse neuroblast cells, and transfers lipophilic Dil dye from the liposomal membrane to the cellular membrane.
In contrast, non-fusogenic pSi particles were found in the cells in small groups indicative of endosomal uptake and lysosomal localization. Additionally, surface conjugation of Neuro2a-targeting moiety, rabies virus glycoprotein RVG , allowed an accelerated rate of fusion of the liposomal pSi.
Overall, the liposomal porous silicon nanoparticles demonstrate potential as a highly effective delivery vehicle. Typically the size is about nm to 1 micrometer.
Here the terms "porous silicon" or "porous silicon oxide" refer to materials containing micropores pore sizes typically smaller than about 2 nm , mesopores pore size typically in the range about nm , or macropores pore sizes larger than about 50 nm , or combinations of any two or all three pore types. Further it should be understood that the surface of the porous materials, including the surface of the inner pore walls, may contain hydrogen, oxygen, or carbon-containing species. In some embodiments, the molecules are anticancer agents, anti-inflammatory agents, small molecule drugs, peptides, polypeptides, nucleic acids e.
Additionally, in contrast to many biologic- derived delivery systems, the nanoparticles alone without an added activating complex or molecule do not induce an immune response. The liposome can be modified to be target specific or can be unmodified see, e.
In one embodiment, the silicon material comprises a silicon dioxide material. In another embodiment, the silicon material comprises both a silicon and a silicon dioxide material. In yet another embodiment, the porous silicon material is loaded with a "payload" material. The payload material can be a drug, small molecule, diagnostic agent, therapeutic agent, peptide, antibody, antibody fragment, polypeptide, nucleic acid e.
In one embodiment, the aqueous solution comprises pure water. X-linked mental retardation: focus on synaptic function and plasticity. J Neurochem 1 : 1— Membrane curvature bends the laws of physics and chemistry. Nat Chem Biol 11 11 : — Phospholipase D: a lipid centric review. Cell Mol Life Sci 62 : — Phospholipase D signalling and its involvement in neurite outgrowth.
Comparative characterization of phosphatidic acid sensors and their localization during frustrated phagocytosis. J Biol Chem 10 : — EMBO J 28 8 : — Diacylglycerol kinases in the regulation of dendritic spines.
J Neurochem 3 : — J Cell Biol 5 : — Multiple actions of secretin in the human body. Int Rev Cytol — Protecting a serial killer: pathways for perforin trafficking and self-defence ensure sequential target cell death. Trends Immunol 33 8 : — Role of tetanus neurotoxin insensitive vesicle-associated membrane protein TI-VAMP in vesicular transport mediating neurite outgrowth.
J Cell Biol 4 : — J Neurosci 30 49 : — Essential role of neuron-enriched diacylglycerol kinase DGK , DGKbeta in neurite spine formation, contributing to cognitive function. PLoS One 5 7 : e Neural cell adhesion molecules of the immunoglobulin superfamily regulate synapse formation, maintenance, and function. Neurosci 40 5 : — Fragile X syndrome: are signaling lipids the missing culprits?
Biochimie — Lipids implicated in the journey of a secretory granule: from biogenesis to fusion. J Neurochem 6 : — Role of phospholipase D-derived phosphatidic acid in regulated exocytosis and neurological disease. Handb Exp Pharmacol. Mol Cell Biol 18 2 : Synthesis of fusogenic lipids through activation of phospholipase D1 by GTPases and the kinase RSK2 is required for calcium-regulated exocytosis in neuroendocrine cells.
Biochem Soc Trans 38 1 : — However, negatively charged exosomal membranes 22 , 23 , 24 repel negatively charged cellular membranes. Because the high abundance of exosomes in serum also leads to competition for their cellular uptake, the internalisation efficiency of exosomes into cells is low and slow. Therefore, further development of strategies for the enhanced cellular uptake of exosomes is urgently required for the delivery of therapeutic molecules.
We studied exosomes that have a negatively charged membrane. Figure 2: Increased cellular uptake of exosomes by treatment with cationic lipids. Scale bar: nm.
Full size image We next examined the effect of cationic lipids on the cellular uptake of the exosomes. The CDGFP-exosomes were mixed with a commercially available cationic lipid formulation, Lipofectamine LTX, which has been widely used for gene transfection 25 as described in the Methods section.
The average diameter of the exosomes was 78 nm as analysed by TEM Fig. However, a WST-1 assay for the detection of cell viability showed that a high concentration of Lipofectamine LTX induced cytotoxicity e. Under the same experimental conditions as described for Fig. For example, Lipofectamine LTX 4. A combination treatment with Lipofectamine LTX for CDGFP-exosomes that were isolated by ultracentrifugation as described in the Methods section was also tested, and similar results showing enhanced cellular uptake efficiency of the exosomes were observed e.
However, as in the case of Fig. Cellular uptake of a pH-sensitive fusogenic peptide, GALA, treated with exosomes and cationic lipids Endocytosis has been shown to be a major pathway for the cellular uptake of exosomes 6 , 7 , 8 , 9 , and barriers imposed by endosomal and exosomal membranes interfere with the cytosolic release of exosomal contents.
Therefore, the cytosolic release efficiency of the exosomal contents e. We previously reported that a pH-sensitive fusogenic peptide, GALA, can enhance the disruption of the endosomal membrane, leading to the efficient cytosolic release of proteins that were conjugated with the GALA peptide inside of the cells 20 , Cationic lipids were also employed to cause the accumulation of the GALA peptide, which carries a negative charge from glutamic acids 7 residues , on the cell surface and accelerate cellular uptake 20 , In this research, we investigated an application of the GALA peptide in a combined treatment of exosomes with cationic lipids for the fusion of exosomal and endosomal membranes inside cells and the enhanced cytosolic release of exosomal contents Fig.
Experiments corresponding to b and c were conducted under the same experimental conditions as a. Conversely, no cytosolic diffusion was observed by the treatment with 0. These results suggested that there should be an optimal concentration of GALA peptide for each Lipofectamine LTX concentration to achieve effective cytosolic release as previously reported by our group 20 , Cellular uptake of dextran-encapsulated exosomes and enhanced cytosolic release by cationic lipids and GALA peptide Next, we examined the cytosolic delivery of cargo-encapsulated exosomes using the combined treatment consisting of the cationic lipids and the GALA peptide.
Dextran 70 kDa was adopted as a model macromolecular cargo in this experiment. It is difficult for dextran to penetrate through the cell membrane by itself. We used Texas red-labelled dextran TR-dex to visualise the intracellular localisation of encapsulated dextran in exosomes delivered using the combined treatment with the cationic lipids and the GALA peptide.
We used an optimized electroporation condition to encapsulate TR-dex into exosomes as described in the Methods section. For this review, all sterol lipids will be considered in the form of cholesterol. Sterol Lipid Structure Cholesterol is defined by its tetracyclic ring structure.
A hydroxyl group is added to one end of this ring structure, which defines that portion as hydrophilic. The combination of the tetracyclic ring and hydroxyl group designates the sterol portion of the molecule Tabas, A hydrocarbon chain is attached to the other end of the sterol. By nature, this hydrocarbon chain is hydrophobic, making cholesterol an amphipathic molecule.
The majority of cholesterol synthesis takes place in the liver, with significant quantities also being produced by the brain, intestines, and adrenal glands Blom et al. Cholesterol synthesis acts through the mevalonate pathway, a complex series of reactions that utilize more than 20 steps Langdon and Bloch, ; Bloch, , ; Figure 4. As such, it is heavily regulated at both transcriptional and post-translational levels Ye and DeBose-Boyd, Mevalonate, via a six enzyme process, is converted to squalene.
Lanosterol, the first cyclic intermediate in the synthesis pathway, is produced from squalene. At this stage, the synthesis pathways diverge into the Kandutsch-Russell or Bloch pathways—depending on the nature of the hydrocarbon chain, before converging at the final product of cholesterol Kandutsch and Russell, ; Bloch, From this point, cholesterol can be used to form bile acids, steroid hormones, or vitamin D Figure 4.
Cholesterol synthesis occurs through diverging pathways for different neuronal cell types. Cholesterol synthesis acts through the mevalonate pathway. Via a complex series of reactions that involve multiple enzymes and reaction steps, mevalonate is converted to squalene. Squalene is converted to lanosterol in an essential cyclization process. From here, the Kandutsch-Russel pathway, which is favored by neuronal cells, produces cholesterol from lanosterol, while the Bloch pathway synthesizes cholesterol that is favored by glial cells.
After cholesterol is synthesized, it can be further metabolized into vitamin D, steroid hormones, or bile acids, or it may be incorporated into cellular membranes. In the brain, the divergent pathways of cholesterol synthesis take precedence in different neuronal tissues. Neurons contain cholesterol variants that arise from the Kandutsch-Russell pathway, while astrocytes favor Bloch pathway variants.
In a similar vein, levels of the intermediate lanosterol are found to be much higher in neurons when compared to astrocytes. Cholesterol levels are also much higher in glial cells Nieweg et al. Together these findings have led to suggestions that neurons have lower capacity for cholesterol synthesis Zhang and Liu, Sterol Lipid Transport Cholesterol transport occurs between and within cells.
As such, transport is an essential mechanism for appropriate cholesterol distribution. Dietary cholesterol is transported from the gut to the liver, and then distributed throughout the body. For this to occur, intestinal enterocytes package cholesterol into chylomicrons, and liver hepatocytes package cholesterol into VLDLs Ikonen, If cholesterol reaches excess in the periphery, transport mechanisms are required to rebalance the distribution.
In such cases, cholesterol is packaged into HDLs, which return it to the liver. In the CNS, lipoproteins are also used to transport cholesterol between multiple cell types Pitas et al. While the ER is the major site of cholesterol synthesis, the concentration of cholesterol at the ER is typically low due to the rapid intracellular transport of cholesterol to appropriate membranes Blom et al. A significant portion of cholesterol is transported to the plasma membrane via non-vesicular mechanisms.
This is proposed to occur via the action of cytosolic carrier proteins, such as sterol carrier protein-2 SCP-2; Puglielli et al. Members of the START family have also been shown to be essential for the transport of cholesterol into the mitochondria Clark et al. A small portion of cholesterol is trafficked through the standard biosynthetic Golgi complex secretory pathway, where it is presented to the plasma membrane. Membrane trafficking via intracellular LDL receptor-mediated uptake brings a portion of cholesterol into the endosomal system, where it is recycled to the plasma membrane and mitochondria Sugii et al.
A final portion of free cholesterol is esterified to form fatty acid sterol esters, which are packaged into lipid droplets for storage Robenek et al. As a result, intracellular cholesterol transport is in a constant state of flux, with high levels of turnover at the ER.
Sphingolipids Sphingolipid Structure Although various forms of sphingolipids exist, all are characterized by the inclusion of a sphingosine backbone. Sphingosine does not apply to a single structure, but is a broad term encompassing various modifications of a long chain base. Significant branching and hydroxyl group additions can also occur.
Depending on the class of sphingolipid, a number of different groups can be added to the sphingosine backbone. The simplest sphingolipids are the ceramides, which consist of a sphingosine backbone linked to a fatty acid chain Pinto et al. There is significant variation in the attached fatty acid, and mammalian sphingolipids typically contain saturated fatty acid chains of between 14 and 32 carbons Merrill et al.
Due to the inclusion of this fatty acid chain, sphingolipids are amphipathic. Other classes of sphingolipids are introduced through the addition of various head groups to ceramide. Sphingomyelins result from the addition of phosphocholine to ceramide Huitema et al. The addition of phosphocholine defines these lipids as phospholipids, and they are therefore also referred to as phosphosphingolipids.
Glycosphingolipids, also referred to as cerebrosides, arise when one or more sugar residues are added to ceramide. Glycosphingolipids of the brain typically have a galactose attached to the ceramide, while non-neuronal tissue favors glucose addition Baumann and Pham-Dinh, Sphingolipid Synthesis Sphingolipid synthesis begins at the cytosolic leaflet of the ER, and progresses to several subcellular locations Gault et al.
At the ER, this process begins with the condensation of palmitoyl CoA and serine to 3-ketosphinganine. A family of dihydro ceramide synthases convert dihydrosphingosine to dihydroceramide. Ceramide synthase 1 is highly expressed in neurons in the brain, while ceramide synthase 2, 5, and 6 are expressed at lower levels Becker et al.
Finally, dihydroceramide desaturase converts dihydroceramide to ceramide. At this stage, ceramide is either used by the cell, or transported elsewhere for further modification. A small portion of ceramide is transported to the luminal leaflet of the ER, where galactosylceramide is generated by ceramide galactosyltransferase CGT.
Galactosylceramide is particularly enriched in the CNS. It is highly expressed in Schwann cells and oligodendrocytes, and is also expressed, albeit at lower levels, in spinal, cerebellar, and brainstem neurons Schaeren-Wiemers et al. The remaining ceramide is transported to the Golgi complex, where one of two enzymes catalyzes the synthesis of two complex sphingolipids.
On the cytosolic side of the Golgi, glucosylceramide synthase GCS converts ceramide to glucosylceramide through the addition of a UDP-glucose group Basu et al. On the luminal side of the Golgi, sphingomyelin synthase SMS converts ceramide to sphingomyelin through the addition of a phosphocholine group Huitema et al.
SMS2, however, is also found on the plasma membrane, suggesting that it may play some role in sphingomyelin metabolism at the plasma membrane Ternes et al. Neuronal sphingolipid synthesis takes place across multiple cellular compartments. Sphingolipid synthesis begins at the cytosolic leaflet of the ER. Via a series of reactions, palmitoyl CoA and serine are converted to ceramide.
A portion of this ceramide is transported to the luminal leaflet of the ER, where ceramide galactosyltransferase CGT converts the ceramide to galactosylceramide; an essential neuronal sphingolipid. Another portion of this ceramide is transported to the Golgi complex, where it is converted to either glucosylceramide on the cytosolic side of the Golgi via glucosylceramide synthase, or to sphingomyelin on the luminal side by sphingomyelin synthase.
Sphingolipid Transport The transport of ceramide from the cytosolic to luminal surface of the ER is currently not understood. It is hypothesized to occur through spontaneous intrabilayer transport or via protein-mediated transport Hanada et al.
Despite the suggestion of protein-mediated transport, no transporter proteins have been implicated to date. Transport from the ER to the Golgi complex occurs via two pathways Figure 5.Treatment of various cancer essay types synthesis lysophosphatidic acid Unisex fashion essay titles the system and release of interleukin 8 IL-8which is a competent angiogenic factor, and thus it has a wordy role in the growth and spread of uprisings by enhancing the hybrid of nutrients and oxygen. The liposomal jimmy can the made from a lipid of goods, wherein the liposomes have a leader between 10 and nm or any background there body e. Role of tetanus neurotoxin exogamous vesicle-associated membrane protein TI-VAMP in vesicular transport producing neurite outgrowth. Phosphatidic acid appears to answer membrane trafficking events,and it is different in activation of the enzyme NADPH oxidase, which classes as part of the the mechanism against caste and body damage during world. Exocytosis: the chromaffin cell as a the hand that signed the paper dylan thomas summary writing system.
In addition, phosphatidic acid is important in the response to other forms of stress, including osmotic stress salinity or drought , cold and oxidation. We then discuss their roles in amyotrophic lateral sclerosis ALS pathogenesis and discuss how modulating lipid function may offer novel therapeutic options. Once bound, the fatty acids diffuse across the membrane in a non-ATP-dependent manner and enter the cytosol.
However, overexpression of autotaxin causes physical defects also and is eventually lethal to embryos. While cyclic phosphatidic acid may have some similar signalling functions to lysophosphatidic acid per se in that it binds to some of the same receptors, it also has some quite distinct activities in animal tissues. In the glycerolphosphate pathway, synthesis begins with glucose, which is converted into glycerolphosphate by a multi-step metabolic reaction. A final portion of free cholesterol is esterified to form fatty acid sterol esters, which are packaged into lipid droplets for storage Robenek et al.
A combination treatment with Lipofectamine LTX for CDGFP-exosomes that were isolated by ultracentrifugation as described in the Methods section was also tested, and similar results showing enhanced cellular uptake efficiency of the exosomes were observed e. At high levels of bacterial burden in the lungs, Staphyloccocal pneumonia becomes fatal due to two major factors: 1 pathogenic activity by S. Incorporation of Fluorescent Cholesterol Derivates into Cardiac Fibroblasts Using Fusogenic Liposomes Besides phospho- and glycolipids two different fluorescent cholesterol derivatives were also delivered to rat embryonic cardiac fibroblasts using fusogenic liposomes. GALA peptide has been used as an additive to improve transfection efficiency and to enhance the escape of nucleic acids from endosomes. It is highly expressed in Schwann cells and oligodendrocytes, and is also expressed, albeit at lower levels, in spinal, cerebellar, and brainstem neurons Schaeren-Wiemers et al.
For example in yeast, phosphatidic acid in the endoplasmic reticulum binds directly to a specific transcriptional repressor to keep it inactive outside the nucleus; when the lipid precursor inositol is added, this phosphatidic acid is rapidly depleted, releasing the transcriptional factor so that it can be translocated to the nucleus where it is able to repress target genes. The binding of exosomes to the surface of a recipient cell involves the interaction of the exosomal membrane molecules and cellular receptors, including intracellular adhesion molecule 1 ICAM1 , lymphocyte function-associated antigen 1 LFA1 , phosphatidylserine binding to T cell immunoglobulin domain and mucin domain protein 1 TIM1 or TIM4 7.