Phospholipid Vesicles Research Articles

Liposomal Formulations to Improve Antioxidant Power of Myrtle Berry Extract for Potential Skin Application

Many substances in plant extracts are known for their biological activities. These substances act in different ways, exerting overall protective effects against many diseases, especially skin disorders. However, plant extracts’ health benefits are often limited by low bioavailability. To overcome these limitations, drug delivery systems can be employed. In this study, we evaluated the antioxidant power of an ethanolic extract from Myrtus communis L. (myrtle) berries through colorimetric tests (DPPH and FRAP). The antioxidant activity was also verified by using fibroblast cell culture through cellular Reactive Oxygen Species (ROS) levels measurements. Moreover, the myrtle extract was formulated in phospholipid vesicles to improve its bioavailability and applicability. Myrtle liposomes were characterized by size, surface charge, storage stability, and entrapment efficiency; visualized by using cryo-TEM images; and assayed for cytocompatibility and anti-ROS activity. Our results suggest that myrtle liposomes were cytocompatible and improved the extract’s antioxidant power in fibroblasts, suggesting a potential skin application for these formulations and confirming that nanotechnologies could be a valid tool to enhance plant extracts’ potentialities.

Formulation and Testing of Antioxidant and Protective Effect of Hyalurosomes Loading Extract Rich in Rosmarinic Acid Biotechnologically Produced from Lavandula angustifolia Miller.

Culture of plant cells or tissues is a scalable, sustainable, and environmentally friendly approach to obtain extracts and secondary metabolites of uniform quality that can be continuously supplied in controlled conditions, independent of geographical and seasonal variations, environmental factors, and negative biological influences. In addition, tissues and cells can be extracted/obtained from the by-products of other industrial cultivations such as that of Lavandula angustifolia Miller (L. angustifolia), which is largely cultivated for the collection of flowers. Given that, an extract rich in rosmarinic acid was biotechnologically produced starting from cell suspension of L. angustifolia, which was then loaded in hyalurosomes, special phospholipid vesicles enriched with sodium hyaluronate, which in turn are capable of both immobilizing and stabilizing the system. These vesicles have demonstrated to be good candidates for skin delivery as their high viscosity favors their residence at the application site, thus promoting their interaction with the skin components. The main physico-chemical and technological characteristics of vesicles (i.e., mean diameter, polydispersity index, zeta potential and entrapment efficiency of extract in vesicles) were measured along with their biological properties in vitro: biocompatibility against fibroblasts and ability to protect the cells from oxidative stress induced by hydrogen peroxide. Overall, preliminary results disclosed the promising properties of obtained formulations to be used for the treatment of skin diseases associated with oxidative stress and inflammation.

Analyzing the Interaction of Fluorescent-Labeled Proteins with Artificial Phospholipid Microvesicles using Quantitative Flow Cytometry.

In the human body, most of the major physiologic reactions involved in the immune response and blood coagulation proceed on the membranes of cells. An important first step in any membrane-dependent reaction is binding of protein on the phospholipid membrane. An approach to studying protein interaction with lipid membranes has been developed using fluorescently labeled proteins and flow cytometry. This method allows the study of protein-membrane interactions using live cells and natural or artificial phospholipid vesicles. The advantage of this method is the simplicity and availability of reagents and equipment. In this method, proteins are labeled using fluorescent dyes. However, both self-made and commercially available, fluorescently labeled proteins can be used. After conjugation with a fluorescent dye, the proteins are incubated with a source of the phospholipid membrane (microvesicles or cells), and the samples are analyzed by flow cytometry. The obtained data can be used to calculate the kinetic constants and equilibrium Kd. In addition, it is possible to estimate the approximate number of protein binding sites on the phospholipid membrane using special calibration beads.

H1 helix of colicin U causes phospholipid membrane permeation.

In light of an increasing number of antibiotic-resistant bacterial strains, it is essential to understand an action imposed by various antimicrobial agents on bacteria at the molecular level. One of the leading mechanisms of killing bacteria is related to the alteration of their plasmatic membrane. We study bio-inspired peptides originating from natural antimicrobial proteins colicins, which can disrupt membranes of bacterial cells. Namely, we focus on the α-helix H1 of colicin U, produced by bacterium Shigella boydii, and compare it with analogous peptides derived from two different colicins. To address the behavior of the peptides in biological membranes, we employ a combination of molecular simulations and experiments. We use molecular dynamics simulations to show that all three peptides are stable in model zwitterionic and negatively charged phospholipid membranes. At the molecular level, their embedment leads to the formation of membrane defects, membrane permeation for water, and, for negatively charged lipids, membrane poration. These effects are caused by the presence of polar moieties in the considered peptides. Importantly, simulations demonstrate that even monomeric H1 peptides can form toroidal pores. At the macroscopic level, we employ experimental co-sedimentation and fluorescence leakage assays. We show that the H1 peptide of colicin U incorporates into phospholipid vesicles and disrupts their membranes, causing leakage, in agreement with the molecular simulations. These insights obtained for model systems seem important for understanding the mechanisms of antimicrobial action of natural bacteriocins and for future exploration of small bio-inspired peptides able to disrupt bacterial membranes.

Functional and structural properties of cardiotoxin isomers produced by blocking negatively charged groups

In this study, we investigated the functional roles of Asp40, Asp57, and C-terminal Asn60 in Naja atra cardiotoxin 3 (CTX3) structure and function by modifying these three carboxyl groups with semicarbazide. The conjugation of the carboxyl groups with semicarbazide produced two conformational isomers whose gross and fine structures were different from those of CTX3. The blocking of the carboxyl groups increased the structural flexibility of CTX3 in response to trifluoroethanol-induced effect. Despite presenting modest to no effect on decreasing the induction of permeability in zwitterionic phospholipid vesicles, the carboxyl group-modified CTX3 showed a marked reduction in its permeabilizing effect on anionic phospholipid vesicles in comparison to that of the native protein. Compared with native CTX3, carboxyl group-modified CTX3 exhibited lower activity in inducing membrane leakage in U937 cells. The CD spectra of lipid-bound toxins and the color transition of polydiacetylene/lipid assay showed that the membrane interaction mode of CTX3 was distinctly changed by the modification in the carboxyl groups. Given that the selective modification of Asp40 does not cause the conformational isomerization of CTX3, our data indicate that the carboxyl groups in Asp57 and Asn60 are essential in maintaining the structural topology of CTX3. Furthermore, modification of carboxyl groups changes the interdependence between the infrastructure and the global conformation of CTX3 in modulating membrane permeabilizing activity.

The interaction of styrene maleic acid copolymers with phospholipids in Langmuir monolayers, vesicles and nanodiscs; a structural study

HypothesisSelf-assembly of amphipathic styrene maleic acid copolymers with phospholipids in aqueous solution results in the formation of ‘nanodiscs’ containing a planar segment of phospholipid bilayer encapsulated by a polymer belt. Recently, studies have reported that lipids rapidly exchange between both nanodiscs in solution and external sources of lipids. Outstanding questions remain regarding details of polymer-lipid interactions, factors influencing lipid exchange and structural effects of such exchange processes. Here, the dynamic behaviour of nanodiscs is investigated, specifically the role of membrane charge and polymer chemistry. ExperimentsTwo model systems are investigated: fluorescently labelled phospholipid vesicles, and Langmuir monolayers of phospholipids. Using fluorescence spectroscopy and time-resolved neutron reflectometry, the membrane potential, monolayer structure and composition are monitored with respect to time upon polymer and nanodisc interactions. FindingsIn the presence of external lipids, polymer chains embed throughout lipid membranes, the extent of which is governed by the net membrane charge. Nanodiscs stabilised by three different polymers will all exchange lipids and polymer with monolayers to differing extents, related to the properties of the stabilising polymer belt. These results demonstrate the dynamic nature of nanodiscs which interact with the local environment and are likely to deposit both lipids and polymer at all stages of use.

Transferosomes: Vesicular Carrier for both Hydrophilic and Lipophilic Drugs

The vesicular system has accessed significant importance towards a sustained drug delivery system in recent years. This article was designed to review the future of vesicular systems known as transferosomes. The vesicles are softer and highly deformable than liposomes. The word Transferosomes is derived from Latin and Greek words called “Transferre” and “soma,” respectively, where Transferre means “carry across” and Soma means “a body.” Transferosomes vesicles are carrying bodies for targeted transdermal drug delivery systems. It consists of phospholipid and an edge activator. In transferosome, phospholipids vesicles act as transdermal drug carriers. It generates an osmotic gradient at the stratum corneum and helps the transferosomes penetrate through the stratum corneum by the transcellular route. Transferosomes have a wide range of solubility, have a remarkable ability to penetrate through the skin, are compatible and biodegradable, and are highly expensive. But they are easily prone to chemical degradation and are highly expensive. The transfersomes were formulated by handshaking, vortex, and freeze-thaw techniques. Transferosomes have various Evaluation parameters such as Vesicle size distribution, the morphology of vesicle, Number of vesicles per cubic mm. Transferosomes have various applications like they can be applied in controlled release and sustained release formulation, transportation of lower and higher molecular weight drug molecules, target drug delivery system, and transdermal immunization. Transferosomes have been ultra-deformable vesicles capable of subjecting a futuristic solution to all vesicular delivery and conventional delivery complications. It can carry any drug’s molecular weight through the skin; due to its ultra-deformable characteristics feature, therefore, they are widely used to take protein and peptides. After doing all the evaluation studies, we can say that Transferosomes are the promising candidate for the vesicular system and can replace other novel vesicular systems. Thus it holds a bright future in novel drug delivery systems.

Modulation of Paracellular-like Drug Transport across an Artificial Biomimetic Barrier by Osmotic Stress-Induced Liposome Shrinking.

Various types of artificial biomimetic barriers are widely utilized as in vitro tools to predict the passive “transcellular” transport of drug compounds. The current study investigated if the sandwich barrier PermeaPad®, which is composed of tightly packed phospholipid vesicles enclosed between two support sheets, contributes to a transport mechanism that is paracellular-like, representing one of the alternative pathways of passive transport in vivo, primarily of relevance for hydrophilic drug compounds. To this end, we pretreated the commercial PermeaPad® barrier with NaCl solutions of either high or low osmolality prior to permeation experiments on reversed Franz cell setups with hydrophilic model compounds calcein and acyclovir and hydrophobic model compounds hydrocortisone and celecoxib. Our starting hypothesis was that the liposomes formed in the barrier during the hydration step should either shrink or swell upon contact with test media (drug solutions) due to osmotic pressure difference as compared to the pretreatment solutions. Apparent permeabilities for calcein and acyclovir across the PermeaPad® barrier were found to increase approximately 2.0 and 1.7 fold, respectively, upon hypo-osmotic pretreatment (soaking in hypotonic medium, while the permeation of hydrocortisone and celecoxib remained unchanged. A control experiment with lipid-free barriers (support sheets) indicated that the permeation of all the compounds was virtually unchanged upon hypo-osmotic pretreatment. In conclusion, soaking PermeaPad® in a medium of lower osmotic pressure than that used during the permeation study appears to induce the osmotic shrinking of the lipid vesicles in the barrier, leaving wider water channels between the vesicles and, thus, allowing hydrophilic compounds to pass the barrier in a paracellular-like manner.

WIND-PVPA: Water/Ion NMR Detected PVPA to assess lipid barrier integrity in vitro through quantification of passive water- and ion transport

Water/Ion NMR Detected – Phospholipid Vesicle Permeability Assay (WIND-PVPA), is presented as a novel, straightforward and automatable method to assess lipid barrier integrity in vitro. The apparent permeability constants of water- and ions across the PVPA barriers are determined in a one-pot experiment under the influence of membrane-active guest molecules. NMR spectroscopy is used to quantify the water directly (D2O) and the ions indirectly (complexed with EDTA) as a function of time. WIND-PVPA is demonstrated using four anti-microbial peptides, to show that membrane active molecules can be differentiated by their disruptive influence on the PVPA system. The results obtained are compared with explicit molecular dynamics simulations of lipid bilayers, AMPs, water and salt, where the motions of all individual water molecules relative to the lipid bilayer are monitored over the course of the simulations, allowing the calculation of theoretical apparent permeability constants of the corresponding single bilayer systems.Proof-of-principle is presented that WIND-PVPA can be used to evaluate the lipid barrier destabilizing effect of active guest molecules by measuring changes in passive water- and ion permeabilities upon exposure. The method is highly flexible in terms of barrier composition, choice of probes and membrane active compounds.

Tempranillo Grape Extract in Transfersomes: A Nanoproduct with Antioxidant Activity.

Polyphenols are gaining increasing interest due to their beneficial properties to human health. Grape pomace, the by-product of wine production, is a source of these bioactive compounds. An extract from Tempranillo grape pomace was obtained and characterized qualitatively and quantitatively. The major components found were anthocyanins, flavan-3-ols, and flavonols. To improve the bioavailability of these compounds, the extract was formulated in phospholipid vesicles, namely transfersomes. Spherical unilamellar vesicles around 100 nm each were obtained. The antioxidant activity of both the extract and the transfersomes was evaluated by using colorimetric assays (i.e., DPPH, FRAP, and Folin–Ciocalteu). The cells’ viability and the antioxidant activity were assessed in keratinocytes. The results showed that the extract and the transfersomes had no cytotoxic effects and exerted remarkable antioxidant activity, which was more evident in a vesicle formulation. These findings highlighted the potential of the Tempranillo grape pomace extract and the efficacy of the incorporation into phospholipid vesicles.

Determination of Optimal Technological Conditions for the Process of Production a Liposomal Dosage Form of Cyphetrylin

Introduction. The Laboratory for the development of dosage forms of the N. N. Blokhin National Medical Research Center of Oncology of the Ministry of Health of Russian Federation has developed a composition of an injectable liposomal dosage form based on soybean phosphatidylcholine, a hydrophobic analog of the hypothalamic hormone somatostatin − cyphetrylin, intended for the treatment of neuroendocrine tumors.Aim. Determination of optimal technological conditions for the process of obtaining a liposomal dosage form of cyphetrylin.Materials and methods. The study used the substance cyphetrylin synthesized in the of Chemical Synthesis Laboratory of the N. N. Blokhin National Medical Research Center of Oncology of the Ministry of Health of Russian Federation; soybean phosphatidylcholine S PC and polyethylene glycol-2000-distearoylphosphatidylethanolamine, produced by Lipoid GmbH (Germany); cholesterol ≥99 % (Sigma-Aldrich, Japan). For the preparation of phospholipid vesicles loaded with cyphetrylin and "empty", the methods of lipid film hydration with subsequent extrusion or homogenization of the dispersion of multi-layer liposomes were used. The obtained liposomal samples were evaluated by quality indicators − the effectiveness of the inclusion of cyphetrylin in vesicles, their average size and surface charge (zeta potential), the viscosity of the dispersion. To evaluate these characteristics, the methods of spectrophotometry, laser scattering spectroscopy, determination of the electrophoretic mobility of particles and viscometry were used.Results and discussion. It was found that the most suitable organic solvent for obtaining a solution of cyphetrylin and lipid components of the dosage form is chloroform. The duration of the drying period of the lipid film under vacuum to remove the residual solvent is determined by the ratio of the volume of the distillation flask used and the mass of its loading its loading. At the same time, hydration off the lipid film with water for injection should be carried out under conditions of low-pressure and room temperature. To obtain a dispersion of single-layer cyphetrylin liposomes of the required size, an extrusion method using nylon and polycarbonate membranes with a filter pore diameter of 0.22 and 0.2 um, respectively, was chosen.Conclusion. The optimal technological conditions for the process of obtaining a liposomal dosage form in the form of a dispersion of a hydrophobic analog of the hypothalamic hormone somatostatin − cyphetrylin are determined.

The combination of MnO2@Lipo-coated gefitinib and bevacizumab inhibits the development of non-small cell lung cancer

It can be found from a large number of cancer treatments that use of anti-cancer drugs alone often presents low efficacy and high side effects. This study aims to develop a new drug carrier with tumor-specific response, controlled release in vivo and high tumor-suppressive property. Inorganic nano-materials MnO2 with pH and glutathione (GSH, abundant in cancer cells) responsiveness were used to construct sustained-release functional nano-liposome to be an excellent in vivo pH-sensitive drug delivery system. Some hydrophilic MnO2, gefitinib (Geb), and bevacizumab (Beb) were encapsulated in the phospholipid vesicles (liposomes), so as to integrate several anti-tumor drugs (MnO2-PDA@Lipo@Geb@Beb) to achieve effective treatment of non-small cell lung cancer (NSCLC). Part of the MnO2 nanorods on the lipid shell had the properties of pH and GSH responsiveness, which could further enhance anti-cancer efficacy. Cell assay results showed that MnO2-PDA@Lipo@Geb@Beb nano-drug had an effective inhibition on A549 cell progression and showed excellent biocompatibility. In vivo results further confirmed that MnO2-PDA@Lipo@Geb@Beb nano-drug could effectively inhibit the growth of NSCLC cells. Overall, it can be inferred from the above experimental results that the nanocomposite drug is expected to be widely used in the clinical application of lung cancer.

Mouthwash Formulation Co-Delivering Quercetin and Mint Oil in Liposomes Improved with Glycol and Ethanol and Tailored for Protecting and Tackling Oral Cavity.

The aim of this work was the simultaneous loading of quercetin and mint essential oil (mint oil) in phospholipid vesicles specifically tailored to obtain an antibacterial and antioxidant mouthwash. The vesicles were prepared using soy lecithin and Tween 80 as bilayer components, and a mixture of phosphate buffer solution (33%), propylene glycol (33%) and ethanol (33%) as dispersing phase. The formation of regularly shaped, spherical and unilamellar vesicles was confirmed by cryogenic transmission electron microscopy analyses. Similarly, light scattering results disclosed that the size of the vesicles increased by increasing the concentration of mint oil, but at the same time the high amount of mint oil ensured high stability, as the size of these vesicles remained unchanged during 12 months of storage. All tested formulations were highly biocompatible towards epithelial cells and capable of counteracting oxidative cell damages caused by hydrogen peroxide. Moreover, the vesicles prepared with the highest concentration of mint oil inhibited the proliferation of the cariogenic Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus).

Translational Research of Hemoglobin Vesicles as a Transfusion Alternative.

Clinical situations arise in which blood for transfusion becomes scarce or unavailable. Considerable demand for a transfusion alternative persists because of various difficulties posed by blood donation and transfusion systems. Hemoglobin-vesicles (Hb- V) are artificial oxygen carriers being developed for use as a transfusion alternative. Just as biomembranes of red blood cells (RBCs) do, phospholipid vesicles (liposomes) for Hb encapsulation can protect the human body from the toxic effects of molecular Hb. The main HbV component, Hb, is obtained from discarded human donated blood. Therefore, HbV can be categorized as a biologic agent targeting oxygen for peripheral tissues. The purification procedure strictly eliminates the possibility of viral contamination. It also removes all concomitant unstable enzymes present in RBC for utmost safety from infection. The deoxygenated HbVs, which are storable for over the years at ambient temperature, can function as an alternative to blood transfusion for resuscitation from hemorrhagic shock and O2 therapeutics. Moreover, a recent study clarified beneficial effects for anti- oxidation and anti-inflammation by carbon monoxide (CO)-bound HbVs. Autoxidation of HbV (HbO2 → metHb + O2 -.) is unavoidable after intravenous administration. Co-injection of methylene blue can extract the intraerythrocytic glycolytic electron energy effectively and reduce metHb. Other phenothiazine dyes can also function as electron mediators to improve the functional life span of HbV. This review paper summarizes recent progress of the research and development of HbV, aimed at clinical applications.

α-Crystallin interacts with the model of human eye lens-lipid membrane via hydrophobic interaction

α-Crystallin, a significant protein of the mammalian eye lens, binds to the lens membrane progressively with age and cataract formation with the corresponding decline in the level of α-crystallin in the lens cytoplasm. Despite various studies of α-crystallin binding to the lens membranes and phospholipid vesicles, the nature of such binding is still unclear. This study investigated a cholesterol/model of human lens-lipid (Chol/MHLL) membrane with Chol/MHLL mixing ratios varying from 0 to 60 mol% Chol.

Metal‐Supported Phospholipid Bilayers Formed by Redox Command (Adv. Mater. Interfaces 6/2022)

A Surface Redox Reaction Lays Down Lipid Membranes In article number 2101289, Ons Hmam and Antonella Badia demonstrate the assembly of single bilayer membranes within minutes at room temperature from phospholipid vesicles in the gel or fluid phase via ion-pairing interactions between the charged lipid head groups and electrogenerated cationic ferroceniums bound to a self-assembled monolayer.

Assembly and architecture of Escherichia coli divisome proteins FtsA and FtsZ

During Escherichia coli cell division, an intracellular complex of cell division proteins known as the Z-ring assembles at midcell during early division and serves as the site of constriction. While the predominant protein in the Z-ring is the widely conserved tubulin homolog FtsZ, the actin homolog FtsA tethers the Z-ring scaffold to the cytoplasmic membrane by binding to FtsZ. While FtsZ is known to function as a dynamic, polymerized GTPase, the assembly state of its partner, FtsA, and the role of ATP are still unclear. We report that a substitution mutation in the FtsA ATP-binding site impairs ATP hydrolysis, phospholipid vesicle remodeling in vitro, and Z-ring assembly in vivo. We demonstrate by transmission electron microscopy and Förster Resonance Energy Transfer that a truncated FtsA variant, FtsA(ΔMTS) lacking a C-terminal membrane targeting sequence, self assembles into ATP-dependent filaments. These filaments coassemble with FtsZ polymers but are destabilized by unassembled FtsZ. These findings suggest a model wherein ATP binding drives FtsA polymerization and membrane remodeling at the lipid surface, and FtsA polymerization is coregulated with FtsZ polymerization. We conclude that the coordinated assembly of FtsZ and FtsA polymers may serve as a key checkpoint in division that triggers cell wall synthesis and division progression.

A Comprehensive Review on Novel Liposomal Methodologies, Commercial Formulations, Clinical Trials and Patents

Liposomes are well-recognized and essential nano-sized drug delivery systems. Liposomes are phospholipid vesicles comprised of cell membrane components and have been employed as artificial cell models to mimic structure and functions of cells and are of immense use in various biological analyses. Liposomes acquire great advantages and provide wide range of applications as useful drug carriers in pre-clinical and clinical trials. This review summarizes exclusively on scalable techniques for liposome preparation and focuses on the strengths and limitations with respect to industrial applicability. Also, this review discusses the updated recent advancements in biomedical applications with a mention of key highlights of commercially available formulations, clinical trials and patents in recent past. Furthermore, this review also provides brief information of the classification, composition and characterization of liposomes.

Nanoparticle tracking analysis and statistical mixture distribution analysis to quantify nanoparticle–vesicle binding

Nanoparticle tracking analysis (NTA) is a single particle tracking technique that in principle provides a more direct measure of particle size distribution compared to dynamic light scattering (DLS). Here, we demonstrate how statistical mixture distribution analysis can be used in combination with NTA to quantitatively characterize the amount and extent of particle binding in a mixture of nanomaterials. The combined approach is used to study the binding of gold nanoparticles to two types of phospholipid vesicles, those containing and lacking the model ion channel peptide gramicidin A. This model system serves as both a proof of concept for the method and a demonstration of the utility of the approach in studying nano-bio interactions. Two diffusional models (Stokes–Einstein and Kirkwood–Riseman) were compared in the determination of particle size, extent of binding, and nanoparticle:vesicle binding ratios for each vesicle type. The combination of NTA and statistical mixture distributions is shown to be a useful method for quantitative assessment of the extent of binding between particles and determination of binding ratios.

Drosophila melanogaster Uncoupling Protein-4A (UCP4A) Catalyzes a Unidirectional Transport of Aspartate.

Uncoupling proteins (UCPs) form a distinct subfamily of the mitochondrial carrier family (MCF) SLC25. Four UCPs, DmUCP4A-C and DmUCP5, have been identified in Drosophila melanogaster on the basis of their sequence homology with mammalian UCP4 and UCP5. In a Parkinson’s disease model, DmUCP4A showed a protective role against mitochondrial dysfunction, by increasing mitochondrial membrane potential and ATP synthesis. To date, DmUCP4A is still an orphan of a biochemical function, although its possible involvement in mitochondrial uncoupling has been ruled out. Here, we show that DmUCP4A expressed in bacteria and reconstituted in phospholipid vesicles catalyzes a unidirectional transport of aspartate, which is saturable and inhibited by mercurials and other mitochondrial carrier inhibitors to various degrees. Swelling experiments carried out in yeast mitochondria have demonstrated that the unidirectional transport of aspartate catalyzed by DmUCP4 is not proton-coupled. The biochemical function of DmUCP4A has been further confirmed in a yeast cell model, in which growth has required an efflux of aspartate from mitochondria. Notably, DmUCP4A is the first UCP4 homolog from any species to be biochemically characterized. In Drosophila melanogaster, DmUCP4A could be involved in the transport of aspartate from mitochondria to the cytosol, in which it could be used for protein and nucleotide synthesis, as well as in the biosynthesis of ß-alanine and N-acetylaspartate, which play key roles in signal transmission in the central nervous system.