Phase-Separated Lipid-Based Nanoparticles: Selective Behavior at the Nano-Bio Interface.

The membrane-protein interface on lipid-based nanoparticles influences their in vivo behavior. Better understanding may evolve current drug delivery methods toward effective targeted nanomedicine. Previously, the cell-selective accumulation of a liposome formulation in vivo is demonstrated, through the recognition of lipid phase-separation by triglyceride lipases. This exemplified how liposome morphology and composition can determine nanoparticle-protein interactions. Here, the lipase-induced compositional and morphological changes of phase-separated liposomes-which bear a lipid droplet in their bilayer- are investigated, and the mechanism upon which lipases recognize and bind to the particles is unravelled. The selective lipolytic degradation of the phase-separated lipid droplet is observed, while nanoparticle integrity remains intact. Next, the Tryptophan-rich loop of the lipase is identified as the region with which the enzymes bind to the particles. This preferential binding is due to lipid packing defects induced on the liposome surface by phase separation. In parallel, the existing knowledge that phase separation leads to in vivo selectivity, is utilized to generate phase-separated mRNA-LNPs that target cell-subsets in zebrafish embryos, with subsequent mRNA delivery and protein expression. Together, these findings can expand the current knowledge on selective nanoparticle-protein communications and in vivo behavior, aspects that will assist to gain control of lipid-based nanoparticles.

Biological recognition and cellular trafficking of targeted RNA-lipid nanoparticles.

Lipid nanoparticles (LNPs) have unlocked the potential of ribonucleic acid (RNA) therapeutics and vaccines. Production and large-scale manufacturing methods for RNA-LNPs have been established and rapidly accelerate. Despite this, basic research on LNPs is still required, due to their high assembly complexity and fairly new development, including research on lipid organization, transfection optimization, and in vivo behavior. Understanding fundamental aspects of LNPs that is, how lipid composition and physicochemical properties affect their biodistribution, cell recognition, and transfection, could propel their clinical development and facilitate overcoming current challenges. Herein, we review recent developments in the field of LNP technology and summarize the main findings focusing on nano-bio interactions.

Fusogenic Coiled-Coil Peptides Enhance Lipid Nanoparticle-Mediated mRNA Delivery upon Intramyocardial Administration.

Heart failure is a serious condition that results from the extensive loss of specialized cardiac muscle cells called cardiomyocytes (CMs), typically caused by myocardial infarction (MI). Messenger RNA (mRNA) therapeutics are emerging as a very promising gene medicine for regenerative cardiac therapy. To date, lipid nanoparticles (LNPs) represent the most clinically advanced mRNA delivery platform. Yet, their delivery efficiency has been limited by their endosomal entrapment after endocytosis. Previously, we demonstrated that a pair of complementary coiled-coil peptides (CPE4/CPK4) triggered efficient fusion between liposomes and cells, bypassing endosomal entrapment and resulting in efficient drug delivery. Here, we modified mRNA-LNPs with the fusogenic coiled-coil peptides and demonstrated efficient mRNA delivery to difficult-to-transfect induced pluripotent stem-cell-derived cardiomyocytes (iPSC-CMs). As proof of in vivo applicability of these fusogenic LNPs, local administration via intramyocardial injection led to significantly enhanced mRNA delivery and concomitant protein expression. This represents the successful application of the fusogenic coiled-coil peptides to improve mRNA-LNPs transfection in the heart and provides the potential for the advanced development of effective regenerative therapies for heart failure.

In vivo metallophilic self-assembly of a light-activated anticancer drug.

Self-assembling molecular drugs combine the easy preparation typical of small-molecule chemotherapy and the tumour-targeting properties of drug-nanoparticle conjugates. However, they require a supramolecular interaction that survives the complex environment of a living animal. Here we report that the metallophilic interaction between cyclometalated palladium complexes generates supramolecular nanostructures in living mice that have a long circulation time (over 12 h) and efficient tumour accumulation rate (up to 10.2% of the injected dose per gram) in a skin melanoma tumour model. Green light activation leads to efficient tumour destruction due to the type I photodynamic effect generated by the self-assembled palladium complexes, as demonstrated in vitro by an up to 96-fold cytotoxicity increase upon irradiation. This work demonstrates that metallophilic interactions are well suited to generating stable supramolecular nanotherapeutics in vivo with exceptional tumour-targeting properties.

Phase-Separated Liposomes Hijack Endogenous Lipoprotein Transport and Metabolism Pathways to Target Subsets of Endothelial Cells In Vivo.

Plasma lipid transport and metabolism are essential to ensure correct cellular function throughout the body. Dynamically regulated in time and space, the well-characterized mechanisms underpinning plasma lipid transport and metabolism offers an enticing, but as yet underexplored, rationale to design synthetic lipid nanoparticles with inherent cell/tissue selectivity. Herein, a systemically administered liposome formulation, composed of just two lipids, that is capable of hijacking a triglyceride lipase-mediated lipid transport pathway resulting in liposome recognition and uptake within specific endothelial cell subsets is described. In the absence of targeting ligands, liposome-lipase interactions are mediated by a unique, phase-separated ("parachute") liposome morphology. Within the embryonic zebrafish, selective liposome accumulation is observed at the developing blood-brain barrier. In mice, extensive liposome accumulation within the liver and spleen - which is reduced, but not eliminated, following small molecule lipase inhibition - supports a role for endothelial lipase but highlights these liposomes are also subject to significant "off-target" by reticuloendothelial system organs. Overall, these compositionally simplistic liposomes offer new insights into the discovery and design of lipid-based nanoparticles that can exploit endogenous lipid transport and metabolism pathways to achieve cell selective targeting in vivo.

Romantic partner embraces reduce cortisol release after acute stress induction in women but not in men.

Stress is omnipresent in our everyday lives. It is therefore critical to identify potential stress-buffering behaviors that can help to prevent the negative effects of acute stress in daily life. Massages, a form of social touch, are an effective buffer against both the endocrinological and sympathetic stress response in women. However, for other forms of social touch, potential stress-buffering effects have not been investigated in detail. Furthermore, the possible stress-buffering effects of social touch on men have not been researched so far. The present study focused on embracing, one of the most common forms of social touch across many cultures. We used a short-term embrace between romantic partners as a social touch intervention prior to the induction of acute stress via the Socially Evaluated Cold Pressor Test. Women who embraced their partner prior to being stressed showed a reduced cortisol response compared to a control group in which no embrace occurred. No stress-buffering effect could be observed in men. No differences between the embrace and control group were observed regarding sympathetic nervous system activation measured via blood pressure or subjective affect ratings. These findings suggest that in women, short-term embraces prior to stressful social situations such as examinations or stressful interviews can reduce the cortisol response in that situation.

Two Types of Liposomal Formulations Improve the Therapeutic Ratio of Prednisolone Phosphate in a Zebrafish Model for Inflammation.

Glucocorticoids (GCs) are effective anti-inflammatory drugs, but their clinical use is limited by their side effects. Using liposomes to target GCs to inflammatory sites is a promising approach to improve their therapeutic ratio. We used zebrafish embryos to visualize the biodistribution of liposomes and to determine the anti-inflammatory and adverse effects of the GC prednisolone phosphate (PLP) encapsulated in these liposomes. Our results showed that PEGylated liposomes remained in circulation for long periods of time, whereas a novel type of liposomes (which we named AmbiMACs) selectively targeted macrophages. Upon laser wounding of the tail, both types of liposomes were shown to accumulate near the wounding site. Encapsulation of PLP in the PEGylated liposomes and AmbiMACs increased its potency to inhibit the inflammatory response. However, encapsulation of PLP in either type of liposome reduced its inhibitory effect on tissue regeneration, and encapsulation in PEGylated liposomes attenuated the activation of glucocorticoid-responsive gene expression throughout the body. Thus, by exploiting the unique possibilities of the zebrafish animal model to study the biodistribution as well as the anti-inflammatory and adverse effects of liposomal formulations of PLP, we showed that PEGylated liposomes and AmbiMACs increase the therapeutic ratio of this GC drug.

Effect of somatotype on the general physical fitness tests and throwing velocity on handball

Abstract Aim: The study aimed to investigate the effects of the somatotype components on handball. Methods: The sample consisted of 60 elite junior handball players. Somatotype was evaluated using the Heath & Carter method. The kinetic performance trials of the handball athletes were running speed performance over 5 m 10 m and 20 m sprints, sit and reach, standing long jump (SLJ), ball velocity, and maximum aerobic power. For the data analyses, we used Pearson correlation and multiple linear regression. Results: The endomorphic component correlated positive with all three sprint times (5 m, 10 m και 30 m sprints) (r = 0.315, p = 0.014; r = 0.367, p = 0.004; r = 0.358, p = 0.005 respectively) while negative with SLJ (r = -0.418, p = 0.001) και maximum aerobic power (r = -0.322, p = 0.012). The mesomorphic component had a positive correlation with ball velocity (r = 0.260, p = 0.045) and negative relation with SLJ (r = -0.261, p = 0.044). The ectomorphic component exhibited a negative correlation only with ball velocity (r = -0.260, p = 0.045). The ordinary least square regression models found that endomorphy and ectomorphy were prognostic factors and predicted worse performance in all of the examined motor performance indices except ball velocity and 5 m sprint, while mesomorphy was a predictor of worse performance in SLJ. Conclusions: In conclusion, according to the findings of this study, somatotype components play an important role in performance-related parameters.

Intracellular Dynamic Assembly of Deep-Red Emitting Supramolecular Nanostructures Based on the Pt Pt Metallophilic Interaction.

Many drug delivery systems end up in the lysosome because they are built from covalent or kinetically inert supramolecular bonds. To reach other organelles, nanoparticles hence need to either be made from a kinetically labile interaction that allows re-assembly of the nanoparticles inside the cell following endocytic uptake, or, be taken up by a mechanism that short-circuits the classical endocytosis pathway. In this work, the intracellular fate of nanorods that self-assemble via the Pt…Pt interaction of cyclometalated platinum(II) compounds, is studied. These deep-red emissive nanostructures (638 nm excitation, ≈700 nm emission) are stabilized by proteins in cell medium. Once in contact with cancer cells, they cross the cell membrane via dynamin- and clathrin-dependent endocytosis. However, time-dependent confocal colocalization and cellular electron microscopy demonstrate that they directly move to mitochondria without passing by the lysosomes. Altogether, this study suggests that Pt…Pt interaction is strong enough to generate emissive, aggregated nanoparticles inside cells, but labile enough to allow these nanostructures to reach the mitochondria without being trapped in the lysosomes. These findings open new venues to the development of bioimaging nanoplatforms based on the Pt…Pt interaction.

Light-triggered switching of liposome surface charge directs delivery of membrane impermeable payloads in vivo.

Surface charge plays a fundamental role in determining the fate of a nanoparticle, and any encapsulated contents, in vivo. Herein, we describe, and visualise in real time, light-triggered switching of liposome surface charge, from neutral to cationic, in situ and in vivo (embryonic zebrafish). Prior to light activation, intravenously administered liposomes, composed of just two lipid reagents, freely circulate and successfully evade innate immune cells present in the fish. Upon in situ irradiation and surface charge switching, however, liposomes rapidly adsorb to, and are taken up by, endothelial cells and/or are phagocytosed by blood resident macrophages. Coupling complete external control of nanoparticle targeting together with the intracellular delivery of encapsulated (and membrane impermeable) cargos, these compositionally simple liposomes are proof that advanced nanoparticle function in vivo does not require increased design complexity but rather a thorough understanding of the fundamental nano-bio interactions involved.

The Self-Assembly of a Cyclometalated Palladium Photosensitizer into Protein-Stabilized Nanorods Triggers Drug Uptake In Vitro and In Vivo.

Enhanced passive diffusion is usually considered to be the primary cause of the enhanced cellular uptake of cyclometalated drugs because cyclometalation lowers the charge of a metal complex and increases its lipophilicity. However, in this work, monocationic cyclometalated palladium complexes [1]OAc (N^N^C^N) and [2]OAc (N^N^N^C) were found to self-assemble, in aqueous solutions, into soluble supramolecular nanorods, while their tetrapyridyl bicationic analogue [3](OAc)2 (N^N^N^N) dissolved as isolated molecules. These nanorods formed via metallophilic Pd···Pd interaction and π-π stacking and were stabilized in the cell medium by serum proteins, in the absence of which the nanorods precipitated. In cell cultures, these protein-stabilized self-assembled nanorods were responsible for the improved cellular uptake of the cyclometalated compounds, which took place via endocytosis (i.e., an active uptake pathway). In addition to triggering self-assembly, cyclometalation in [1]OAc also led to dramatically enhanced photodynamic properties under blue light irradiation. These combined penetration and photodynamic properties were observed in multicellular tumor spheroids and in a mice tumor xenograft, demonstrating that protein-stabilized nanoaggregation of cyclometalated drugs such as [1]OAc also allows efficient cellular uptake in 3D tumor models. Overall, serum proteins appear to be a major element in drug design because they strongly influence the size and bioavailability of supramolecular drug aggregates and hence their efficacy in vitro and in vivo.

Oxyanion transport across lipid bilayers: direct measurements in large and giant unilamellar vesicles.

A simple di(thioamido)carbazole 1 serves as a potent multispecific transporter for various biologically relevant oxyanions, such as drugs, metabolites and model organic phosphate. The transport kinetics of a wide range of oxyanions can be easily quantified by a modified lucigenin assay in both large and giant unilamellar vesicles.

Beta-orcinol metabolites from the lichen Hypotrachyna revoluta.

Four new beta-orcinol metabolites, hypotrachynic acid (1), deoxystictic acid (2), cryptostictinolide (3) and 8'-methylconstictic acid (4) along with the metabolites 8'-methylstictic acid (5), 8'-methylmenegazziaic acid (6), stictic acid (7), 8'-ethylstictic acid (8) and atranorin (9), that have been previously described, were isolated for the first time from the tissue extracts of the lichen Hypotrachyna revoluta (Flörke) Hale. The structures of the new metabolites were elucidated on the basis of extensive spectroscopic analyses. Radical scavenging activity (RSA) of the metabolites isolated in adequate amounts, was evaluated using luminol chemiluminescence and comparison with Trolox.