Characterization and purification of pentameric chimeric protein particles using asymmetric flow field-flow fractionation coupled with multiple detectors.

Porcine circovirus causes the post-weaning multi-systemic wasting syndrome. Despite the existence of commercial vaccines, the development of more effective and cheaper vaccines is expected. The usage of chimeric antigens allows serological differentiation between naturally infected and vaccinated animals. In this work, recombinant pentameric vaccination protein particles spontaneously assembled from identical subunits-chimeric fusion proteins derived from circovirus capsid antigen Cap and a multimerizing subunit of mouse polyomavirus capsid protein VP1 were purified and characterized using asymmetric flow field-flow fractionation (AF4) coupled with UV and MALS/DLS (multi-angle light scattering/dynamic light scattering) detectors. Various elution profiles were tested, including constant cross-flow and decreasing cross-flow (linearly and exponentially). The optimal sample retention, separation efficiency, and resolution were assessed by the comparison of the hydrodynamic radius (Rh) measured by online DLS with the Rh values calculated from the simplified retention equation according to the AF4 theory. The results show that the use of the combined elution profiles (exponential and constant cross-flow rates) reduces the time of the separation, prevents undesirable sample-membrane interaction, and yields better resolution. Besides, the results show no self-associations of the individual pentameric particles into larger clusters and no sample degradation during the AF4 separation. The Rg/Rh ratios for different fractions are in good correlation with morphological analyses performed by transmission electron microscopy (TEM). Additionally to the online analysis, the individual fractions were subjected to offline analysis, including batch DLS, TEM, and SDS-PAGE, followed by Western blot.

Gadolinium labelled nanoliposomes as the platform for MRI theranostics: in vitro safety study in liver cells and macrophages.

Gadolinium (Gd)-based contrast agents are extensively used for magnetic resonance imaging (MRI). Liposomes are potential nanocarrier-based biocompatible platforms for development of new generations of MRI diagnostics. Liposomes with Gd-complexes (Gd-lip) co-encapsulated with thrombolytic agents can serve both for imaging and treatment of various pathological states including stroke. In this study, we evaluated nanosafety of Gd-lip containing PE-DTPA chelating Gd+3 prepared by lipid film hydration method. We detected no cytotoxicity of Gd-lip in human liver cells including cancer HepG2, progenitor (non-differentiated) HepaRG, and differentiated HepaRG cells. Furthermore, no potential side effects of Gd-lip were found using a complex system including general biomarkers of toxicity, such as induction of early response genes, oxidative, heat shock and endoplasmic reticulum stress, DNA damage responses, induction of xenobiotic metabolizing enzymes, and changes in sphingolipid metabolism in differentiated HepaRG. Moreover, Gd-lip did not show pro-inflammatory effects, as assessed in an assay based on activation of inflammasome NLRP3 in a model of human macrophages, and release of eicosanoids from HepaRG cells. In conclusion, this in vitro study indicates potential in vivo safety of Gd-lip with respect to hepatotoxicity and immunopathology caused by inflammation.

Preparation of nanoliposomes by microfluidic mixing in herring-bone channel and the role of membrane fluidity in liposomes formation.

Introduction of microfluidic mixing technique opens a new door for preparation of the liposomes and lipid-based nanoparticles by on-chip technologies that are applicable in a laboratory and industrial scale. This study demonstrates the role of phospholipid bilayer fragment as the key intermediate in the mechanism of liposome formation by microfluidic mixing in the channel with "herring-bone" geometry used with the instrument NanoAssemblr. The fluidity of the lipid bilayer expressed as fluorescence anisotropy of the probe N,N,N-Trimethyl-4-(6-phenyl-1,3,5-hexatrien-1-yl) was found to be the basic parameter affecting the final size of formed liposomes prepared by microfluidic mixing of an ethanol solution of lipids and water phase. Both saturated and unsaturated lipids together with various content of cholesterol were used for liposome preparation and it was demonstrated, that an increase in fluidity results in a decrease of liposome size as analyzed by DLS. Gadolinium chelating lipids were used to visualize the fine structure of liposomes and bilayer fragments by CryoTEM. Experimental data and theoretical calculations are in good accordance with the theory of lipid disc micelle vesiculation.

Targeting Human Thrombus by Liposomes Modified with Anti-Fibrin Protein Binders.

Development of tools for direct thrombus imaging represents a key step for diagnosis and treatment of stroke. Nanoliposomal carriers of contrast agents and thrombolytics can be functionalized to target blood thrombi by small protein binders with selectivity for fibrin domains uniquely formed on insoluble fibrin. We employed a highly complex combinatorial library derived from scaffold of 46 amino acid albumin-binding domain (ABD) of streptococcal protein G, and ribosome display, to identify variants recognizing fibrin cloth in human thrombus. We constructed a recombinant target as a stretch of three identical fibrin fragments of 16 amino acid peptide of the Bß chain fused to TolA protein. Ribosome display selection followed by large-scale Enzyme-Linked ImmunoSorbent Assay (ELISA) screening provided four protein variants preferentially binding to insoluble form of human fibrin. The most specific binder variant D7 was further modified by C-terminal FLAG/His-Tag or double His-tag for the attachment onto the surface of nanoliposomes via metallochelating bond. D7-His-nanoliposomes were tested using in vitro flow model of coronary artery and their binding to fibrin fibers was demonstrated by confocal and electron microscopy. Thus, we present here the concept of fibrin-targeted binders as a platform for functionalization of nanoliposomes in the development of advanced imaging tools and future theranostics.

Application of Advanced Microscopic Methods to Study the Interaction of Carboxylated Fluorescent Nanodiamonds with Membrane Structures in THP-1 Cells: Activation of Inflammasome NLRP3 as the Result of Lysosome Destabilization.

Nanodiamonds (ND), especially fluorescent NDs, represent potentially applicable drug and probe carriers for in vitro/in vivo applications. The main purpose of this study was to relate physical-chemical properties of carboxylated NDs to their intracellular distribution and impact on membranes and cell immunity-activation of inflammasome in the in vitro THP-1 cell line model. Dynamic light scattering, nanoparticle tracking analysis, and microscopic methods were used to characterize ND particles and their intracellular distribution. Fluorescent NDs penetrated the cell membranes by both macropinocytosis and mechanical cutting through cell membranes. We proved accumulation of fluorescent NDs in lysosomes. In this case, lysosomes were destabilized and cathepsin B was released into the cytoplasm and triggered pathways leading to activation of inflammasome NLRP3, as detected in THP-1 cells. Activation of inflammasome by NDs represents an important event that could underlie the described toxicological effects in vivo induced by NDs. According to our knowledge, this is the first in vitro study demonstrating direct activation of inflammasome by NDs. These findings are important for understanding the mechanism(s) of action of ND complexes and explain the ambiguity of the existing toxicological data.

N-Oxy lipid-based click chemistry for orthogonal coupling of mannan onto nanoliposomes prepared by microfluidic mixing: Synthesis of lipids, characterisation of mannan-coated nanoliposomes and in vitro stimulation of dendritic cells.

New synthetic aminooxy lipid was designed and synthesized as a building block for the formulation of functionalised nanoliposomes (presenting onto the outer surface of aminooxy groups) by microfluidic mixing. Orthogonal binding of cellular mannan (Candida glabrata (CCY 26-20-1) onto the outer surface of functionalised nanoliposomes was modified by orthogonal binding of reducing termini of mannans to oxime lipids via a click chemistry reaction based on aminooxy coupling (oxime ligation). The aminooxy lipid was proved as a suitable active component for preparation of functionalised nanoliposomes by the microfluidic mixing method performed with the instrument NanoAssemblr™. This "on-chip technology" can be easily scaled-up. The structure of mannan-liposomes was visualized by transmission and scanning electron microscopy, including immunogold staining of recombinant mannan receptor bound onto mannosylated-liposomes. The observed structures are in a good correlation with data obtained by DLS, NTA, and TPRS methods. In vitro experiments on human and mouse dendritic cells demonstrate selective internalisation of fluorochrome-labelled mannan-liposomes and their ability to stimulate DC comparable to lipopolysaccharide. We describe a potentially new drug delivery platform for mannan receptor-targeted antimicrobial drugs as well as for immunotherapeutics. Furthermore, the platform based on mannans bound orthogonally onto the surface of nanoliposomes represents a self-adjuvanted carrier for construction of liposome-based recombinant vaccines for both systemic and mucosal routes of administration.

Hyaluronic Acid Surface Modified Liposomes Prepared via Orthogonal Aminoxy Coupling: Synthesis of Nontoxic Aminoxylipids Based on Symmetrically α-Branched Fatty Acids, Preparation of Liposomes by Microfluidic Mixing, and Targeting to Cancer Cells Expressing CD44.

New synthetic aminoxy lipids are designed and synthesized as building blocks for the formulation of functionalized nanoliposomes by microfluidization using a NanoAssemblr. Orthogonal binding of hyaluronic acid onto the outer surface of functionalized nanoliposomes via aminoxy coupling ( N-oxy ligation) is achieved at hemiacetal function of hyaluronic acid and the structure of hyaluronic acid-liposomes is visualized by transmission electron microscopy and cryotransmission electron microscopy. Observed structures are in a good correlation with data obtained by dynamic light scattering (size and ζ-potential). In vitro experiments on cell lines expressing CD44 receptors demonstrate selective internalization of fluorochrome-labeled hyaluronic acid-liposomes, while cells with down regulated CD44 receptor levels exhibit very low internalization of hyaluronic acid-liposomes. A method based on microfluidization mixing was developed for preparation of monodispersive unilamellar liposomes containing aminoxy lipids and orthogonal binding of hyaluronic acid onto the liposomal surface was demonstrated. These hyaluronic acid-liposomes represent a potentially new drug delivery platform for CD44-targeted anticancer drugs as well as for immunotherapeutics and vaccines.

Increased Carbohydrate Intake is Associated with Poorer Performance in Verbal Memory and Attention in an APOE Genotype-Dependent Manner.

Evidence suggests that a diet low in carbohydrates can impact on cognitive performance among those with Alzheimer's disease (AD). However, there is a lack of data assessing this relationship among cognitively normal (CN) older adults at increased future risk of developing AD due to carriage of the apolipoprotein E (APOE) ɛ4 allele. We assessed the cross-sectional association between carbohydrate intake, cognitive performance, and cerebral amyloid-ß (Aß) load in CN older adults, genotyped for APOEɛ4 allele carrier status. Greater carbohydrate intake was associated with poorer performance in verbal memory in APOEɛ4 allele non-carriers, and poorer performance in attention in APOEɛ4 allele carriers. There were no associations between carbohydrate intake and cerebral Aß load. These results provide support to the idea that decreasing carbohydrate intake may offer neurocognitive benefits, with specific cognitive domains affected in an APOE genotype-dependent manner. These findings warrant further investigation utilizing a longitudinal study design.

Plasma apolipoprotein J as a potential biomarker for Alzheimer's disease: Australian Imaging, Biomarkers and Lifestyle study of aging.

INTRODUCTION: For early detection of Alzheimer's disease (AD), the field needs biomarkers that can be used to detect disease status with high sensitivity and specificity. Apolipoprotein J (ApoJ, also known as clusterin) has long been associated with AD pathogenesis through various pathways. The aim of this study was to investigate the potential of plasma apoJ as a blood biomarker for AD. METHODS: Using the Australian Imaging, Biomarkers and Lifestyle (AIBL) study of aging, the present study assayed plasma apoJ levels over baseline and 18 months in 833 individuals. Plasma ApoJ levels were analyzed with respect to clinical classification, age, gender, apolipoprotein E (APOE) ε4 allele status, mini-mental state examination score, plasma amyloid beta (Aß), neocortical Aß burden (as measured by Pittsburgh compound B-positron emission tomography), and total adjusted hippocampus volume. RESULTS: ApoJ was significantly higher in both mild cognitive impairment (MCI) and AD groups as compared with healthy controls (HC; P < .0001). ApoJ significantly correlated with both "standardized uptake value ratio" (SUVR) and hippocampus volume and weakly correlated with the plasma Aß1-42/Aß1-40 ratio. Plasma apoJ predicted both MCI and AD from HC with greater than 80% accuracy for AD and greater than 75% accuracy for MCI at both baseline and 18-month time points. DISCUSSION: Mean apoJ levels were significantly higher in both MCI and AD groups. ApoJ was able to differentiate between HC with high SUVR and HC with low SUVR via APOE ε4 allele status, indicating that it may be included in a biomarker panel to identify AD before the onset of clinical symptoms.

Vitamin D2-enriched button mushroom (Agaricus bisporus) improves memory in both wild type and APPswe/PS1dE9 transgenic mice.

Vitamin D deficiency is widespread, affecting over 30% of adult Australians, and increasing up to 80% for at-risk groups including the elderly (age>65). The role for Vitamin D in development of the central nervous system is supported by the association between Vitamin D deficiency and incidence of neurological and psychiatric disorders including Alzheimer's disease (AD). A reported positive relationship between Vitamin D status and cognitive performance suggests that restoring Vitamin D status might provide a cognitive benefit to those with Vitamin D deficiency. Mushrooms are a rich source of ergosterol, which can be converted to Vitamin D2 by treatment with UV light, presenting a new and convenient dietary source of Vitamin D2. We hypothesised that Vitamin D2-enriched mushrooms (VDM) could prevent the cognitive and pathological abnormalities associated with dementia. Two month old wild type (B6C3) and AD transgenic (APPSwe/PS1dE9) mice were fed a diet either deficient in Vitamin D2 or a diet which was supplemented with VDM, containing 1±0.2 µg/kg (∼54 IU/kg) vitamin D2, for 7 months. Effects of the dietary intervention on memory were assessed pre- and post-feeding. Brain sections were evaluated for amyloid ß (Aß) plaque loads and inflammation biomarkers using immuno-histochemical methods. Plasma vitamin D metabolites, Aß40, Aß42, calcium, protein and cholesterol were measured using biochemical assays. Compared with mice on the control diet, VDM-fed wild type and AD transgenic mice displayed improved learning and memory, had significantly reduced amyloid plaque load and glial fibrillary acidic protein, and elevated interleukin-10 in the brain. The results suggest that VDM might provide a dietary source of Vitamin D2 and other bioactives for preventing memory-impairment in dementia. This study supports the need for a randomised clinical trial to determine whether or not VDM consumption can benefit cognitive performance in the wider population.