Extracellular vimentin is sufficient to promote cell attachment, spreading, and motility by a mechanism involving N-acetyl glucosamine-containing structures.

Vimentin intermediate filaments form part of the cytoskeleton of mesenchymal cells, but under pathological conditions often associated with inflammation, vimentin filaments depolymerize as the result of phosphorylation or citrullination, and vimentin oligomers are secreted or released into the extracellular environment. In the extracellular space, vimentin can bind surfaces of cells and the extracellular matrix, and the interaction between extracellular vimentin and cells can trigger changes in cellular functions, such as activation of fibroblasts to a fibrotic phenotype. The mechanism by which extracellular vimentin binds external cell membranes and whether vimentin alone can act as an adhesive anchor for cells is largely uncharacterized. Here, we show that various cell types (normal and vimentin null fibroblasts, mesenchymal stem cells, and A549 lung carcinoma cells) attach to and spread on polyacrylamide hydrogel substrates covalently linked to vimentin. Using traction force microscopy and spheroid expansion assays, we characterize how different cell types respond to extracellular vimentin. Cell attachment to and spreading on vimentin-coated surfaces is inhibited by hyaluronic acid degrading enzymes, hyaluronic acid synthase inhibitors, soluble heparin or N-acetyl glucosamine, all of which are treatments that have little or no effect on the same cell types binding to collagen-coated hydrogels. These studies highlight the effectiveness of substrate-bound vimentin as a ligand for cells and suggest that carbohydrate structures, including the glycocalyx and glycosylated cell surface proteins that contain N-acetyl glucosamine, form a novel class of adhesion receptors for extracellular vimentin that can either directly support cell adhesion to a substrate or fine-tune the glycocalyx adhesive properties.

Polymer Network Comprised of Steroidal Rotors as a Promising Storage Material.

The front cover artwork is provided by Dr habil. Izabella Jastrzebska's group from the University of Bialystok, Poland. The image shows a polymeric network with molecular rotors (MR) as crosslinks. The MR rotation is slowed or inhibited when a molecule of stored gas is placed inside the polymer material. Read the full text of the Research Article at 10.1002/cphc.202300793.

Polymer network comprised of steroidal rotors as promising storage material.

In this paper, we report a new generation of polymeric networks as potential functional material based on changes in molecular dynamics in the solid state. The material is obtained by free radical polymerization of a diacrylate derivative bearing a steroid (stator) and a 1,4-diethynyl-phenylene-d4 fragment (rotator). Polymer research using the PALS technique complements the knowledge about nanostructural changes occurring in the system in the temperature range -115 °C - +190 °C. It indicates the presence of two types of free nanovolumes in the system and the occurrence of phase transitions. The polymer is characterized using 1 H NMR, 2 H Solid Echo NMR, ATR-FTIR and Raman spectroscopies, thermal analysis, and porosimetry. It is proved that the applied procedure leads to the formation of a novel porous organic material containing multiple molecular rotors.

Membrane-Active Thermoresponsive Block Copolymers Containing a Diacylglycerol-Based Segment: RAFT Synthesis, Doxorubicin Encapsulation, and Evaluation of Cytotoxicity against Breast Cancer Cells.

Herein, we report the formation of drug delivery systems from original thermoresponsive block copolymers containing lipid-based segments. Two acrylate monomers derived from palmitic- or oleic-acid-based diacylglycerols (DAGs) were synthesized and polymerized by the reversible addition-fragmentation chain transfer (RAFT) method. Well-defined DAG-based polymers with targeted molar masses and narrow molar mass distributions were next used as macro-chain transfer agents (macro-CTAs) for the polymerization of N-isopropylacrylamide (NIPAAm) or N-vinylcaprolactam (NVCL). The obtained amphiphilic block copolymers were formed into polymeric nanoparticles (PNPs) with and without encapsulated doxorubicin and characterized. Their biological assessment indicated appropriate cytocompatibility with the representatives of normal cells. Furthermore, compared to the free drug, increased cytotoxicity and apoptosis or necrosis induction in breast cancer cells was documented, including a highly aggressive and invasive triple-negative MDA-MB-231 cell line.

Optimization of Multilayer Films Composed of Chitosan and Low-Methoxy Amidated Pectin as Multifunctional Biomaterials for Drug Delivery.

Polyelectrolyte multilayers (PEMs) based on polyelectrolyte complex (PEC) structures are recognized as interesting materials for manufacturing functionalized coatings or drug delivery platforms. Difficulties in homogeneous PEC system development generated the idea of chitosan (CS)/low-methoxy amidated pectin (LM PC) multilayer film optimization with regard to the selected variables: the polymer ratio, PC type, and order of polymer mixing. Films were formulated by solvent casting method and then tested to characterize CS/LM PC PECs, using thermal analysis, Fourier transform infrared spectroscopy (FTIR), turbidity, and zeta potential measurements. The internal structure of the films was visualized by using scanning electron microscopy. Analysis of the mechanical and swelling properties enabled us to select the most promising formulations with high uniformity and mechanical strength. Films with confirmed multilayer architecture were indicated as a promising material for the multifunctional systems development for buccal drug delivery. They were also characterized by improved thermal stability as compared to the single polymers and their physical mixtures, most probably as a result of the CS-LM PC interactions. This also might indicate the potential protective effect on the active substances being incorporated in the PEC-based films.

Susceptibility of microbial cells to the modified PIP2-binding sequence of gelsolin anchored on the surface of magnetic nanoparticles.

BACKGROUND: Magnetic nanoparticles (MNPs) are characterized by unique physicochemical and biological properties that allow their employment as highly biocompatible drug carriers. Gelsolin (GSN) is a multifunctional actin-binding protein involved in cytoskeleton remodeling and free circulating actin sequestering. It was reported that a gelsolin derived phosphoinositide binding domain GSN 160-169, (PBP10 peptide) coupled with rhodamine B, exerts strong bactericidal activity. RESULTS: In this study, we synthesized a new antibacterial and antifungal nanosystem composed of MNPs and a PBP10 peptide attached to the surface. The physicochemical properties of these nanosystems were analyzed by spectroscopy, calorimetry, electron microscopy, and X-ray studies. Using luminescence based techniques and a standard killing assay against representative strains of Gram-positive (Staphylococcus aureus MRSA Xen 30) and Gram-negative (Pseudomonas aeruginosa Xen 5) bacteria and against fungal cells (Candida spp.) we demonstrated that magnetic nanoparticles significantly enhance the effect of PBP10 peptides through a membrane-based mode of action, involving attachment and interaction with cell wall components, disruption of microbial membrane and increased uptake of peptide. Our results also indicate that treatment of both planktonic and biofilm forms of pathogens by PBP10-based nanosystems is more effective than therapy with either of these agents alone. CONCLUSIONS: The results show that magnetic nanoparticles enhance the antimicrobial activity of the phosphoinositide-binding domain of gelsolin, modulate its mode of action and strengthen the idea of its employment for developing the new treatment methods of infections.

The Spray-Dried Alginate/Gelatin Microparticles with Luliconazole as Mucoadhesive Drug Delivery System.

Candida species are opportunistic fungi, which are primary causative agents of vulvovaginal candidiasis. The cure of candidiasis is difficult, lengthy, and associated with the fungi resistivity. Therefore, the research for novel active substances and unconventional drug delivery systems providing effective and safe treatment is still an active subject. Microparticles, as multicompartment dosage forms due to larger areas, provide short passage of drug diffusion, which might improve drug therapeutic efficiency. Sodium alginate is a natural polymer from a polysaccharide group, possessing swelling, mucoadhesive, and gelling properties. Gelatin A is a natural high-molecular-weight polypeptide obtained from porcine collagen. The purpose of this study was to prepare microparticles by the spray-drying of alginate/gelatin polyelectrolyte complex mixture, with a novel antifungal drug-luliconazole. In the next stage of research, the effect of gelatin presence on pharmaceutical properties of designed formulations was assessed. Interrelations among polymers were evaluated with thermal analysis and Fourier transform infrared spectroscopy. A valid aspect of this research was the in vitro antifungal activity estimation of designed microparticles using Candida species: C. albicans, C. krusei, and C. parapsilosis. It was shown that the gelatin addition affected the particles size, improved encapsulation efficiency and mucoadhesiveness, and prolonged the drug release. Moreover, gelatin addition to the formulations improved the antifungal effect against Candida species.

Doxorubicin delivery systems with an acetylacetone-based block in cholesterol-terminated copolymers: Diverse activity against estrogen-dependent and estrogen-independent breast cancer cells.

The study presents the synthesis of original cholesterol-terminated copolymers comprising acetylacetone-based (AcacI) and N-isopropylacrylamide (NIPAAm) units with a varied arrangement (block and random copolymers). The nanoprecipitation method was used to form empty and doxorubicin-loaded polymeric nanoparticles (PNPs) from these copolymers, which were further studied in terms of their physicochemical and biological properties. Unexpectedly, it was revealed that even empty PNPs are effective against breast cancer cells, specifically towards estrogen-dependent MCF-7 cell line. The anti-cancer efficacy was further improved when a low dose of doxorubicin was introduced to the tested systems. It was shown that the proposed carriers modulate doxorubicin (DOX) compatibility with representatives of normal cells, including immune cells, cardiomyocyte cells, and fibroblasts, and reduce side effects associated with standard chemotherapy. The use of these carriers might be a strategy leading to enhancement of DOX activity in cancer cells which develop resistance through decreased drug penetration or drug efflux.

Polymeric Drug Delivery Systems Bearing Cholesterol Moieties: A Review.

This review aims to provide an overview of polymers comprising cholesterol moiety/ies designed to be used in drug delivery. Over the last two decades, there have been many papers published in this field, which are summarized in this review. The primary focus of this article is on the methods of synthesis of polymers bearing cholesterol in the main chain or as side chains. The data related to the composition, molecular weight, and molecular weight distribution of polymers are presented. Moreover, other aspects, such as forms of carriers, types of encapsulated drugs, encapsulation efficiency and capacity, are also included.

Evaluation of Cytotoxic Effect of Cholesterol End-Capped Poly(N-Isopropylacrylamide)s on Selected Normal and Neoplastic Cells.

PURPOSE: Efficient intracellular delivery of a therapeutic compound is an important feature of smart drug delivery systems (SDDS). Modification of a carrier structure with a cell-penetrating ligand, ie, cholesterol moiety, is a strategy to improve cellular uptake. Cholesterol end-capped poly(N-isopropylacrylamide)s offer a promising foundation for the design of efficient thermoresponsive drug delivery systems. METHODS: A series of cholesterol end-capped poly(N-isopropylacrylamide)s (PNIPAAm) with number-average molar masses ranging from 3200 to 11000 g·mol-1 were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization from original xanthate-functionalized cholesterol and self-assembled into micelles. The physicochemical characteristics and cytotoxicity of cholesterol end-capped poly(N-isopropylacrylamide)s have been thoroughly investigated. RESULTS: Phase transition temperature dependence on the molecular weight and hydrophilic/hydrophobic ratio in the polymers were observed in water. Biological test results showed that the obtained materials, both in disordered and micellar form, are non-hemolytic, highly compatible with fibroblasts, and toxic to glioblastoma cells. It was found that the polymer termini dictates the mode of action of the system. CONCLUSION: The cholesteryl moiety acts as a cell-penetrating agent, which enables disruption of the plasma membrane and in effect leads to the restriction of the tumor growth. Cholesterol end-capped PNIPAAm showing in vitro anticancer efficacy can be developed not only as drug carriers but also as components of combined/synergistic therapy.

Aggregation studies of n-alkanoyl-N-methyllactitolamine surfactants.

The micellization processes of n-alkanoyl-N-methyllactitolamines (CnMeLA) were studied by means of isothermal titration calorimetry (ITC) and compared with those of decanoyl-N-methyl glucamide (MEGA-10). The critical micelle concentrations (cmc), the enthalpies (deltaH(m)) and the entropies (deltaS(m)0) of micellization as well as the contributions of the head groups to the Gibbs free energies (deltaG(m)0 (hy)) were calculated. The molecular modeling studies including the conformational analysis and calculations of some molecular descriptors related to hydrophilic and hydrophobic interactions were done to elucidate the experimental results at the atomic level. Despite the significantly bigger size of the headgroup of CnMeLA, the value of deltaG(m)0 (hy) for this compound is close to those for the MEGA-n and CnGluc. The introduction of gluco ring to polyoxyethylene chain of MEGA-10 decreases its hydrophobicity to a similar extent as shortening of the alkyl chain by one methylene group. Molecular modeling studies suggest that these effects came from conformational properties of the gluco ring and polyoxyethylene chain, which are different when they constitute CnMeLA headgroup and when they constitute head groups of CnGluc and MEGA-10, respectively.

The influence of cholesterol on the interaction between N-dodecyl-N,N-dimethyl-N-benzylammonium halides and phosphatidylcholine bilayers.

Effects of N-dodecyl-N,N-dimethyl-N-benzylammonium halides (DBeAX) on thermotropic phase behavior of phosphatidylcholine/cholesterol bilayers as well as on 1H NMR spectra were studied. The surfactants were added either to the water phase or directly to the lipid phase (a mixed film was formed). The benzyl group, opposite to liposomes without cholesterol, is not incorporated into the bilayer in the gel state but only in the liquid state. All the halides DBeAX (particularly the chloride DBeAC) showed greater ability to destabilize the membrane structure in the presence than in the absence of cholesterol. The interaction of DBeAX with DPPC/cholesterol bilayers and subsequent changes in the phospholipid bilayer organization depended on the kind of counterion. The strongest effects were observed for chloride (most electronegative ion) and for iodide (largest ion). The effects of chloride and bromide on phase transition and 1H NMR spectra in the presence and absence of cholesterol were opposite. This is discussed in terms of the influence of counterions on the pair cholesterol-DPPC interactions.

Nonviral gene delivery: gemini bispyridinium surfactant-based DNA nanoparticles.

The interaction with a model membrane, the formation of DNA nanoparticles, and the transfection ability of a homologous series of bispyridinium dihexadecyl cationic gemini surfactants, differing in the length of the alkyl spacer bridging the two pyridinium polar heads in the 1 and 1' positions (P16-n with n = 3, 4, 8, 12), have been studied by means of differential scanning calorimetry (DSC), atomic force microscopy, electrophoresis mobility shift assay, and transient transfection assay measurements. The results presented here show that their performance in gene delivery is strictly related to their structure in solution. For the first time the different transfection activities of the compounds can be explained by referring to their thermodynamic properties in solution, previously studied. The compound with a spacer formed by four carbon atoms, showing unexpected enthalpic properties vs concentration in solution, is the only one giving rise to a transfection activity comparable to that of the commercial reagent, when formulated with L-α-dioleoylphosphatidylethanolamine. We suggest that P16-4 behaves like molecular tongs able to grip basic groups near each other, allowing the formation of compact and nearly spherical DNA particles. The compound with the longest spacer gives rise to loosely condensed structures by forming a sort of bow, not able to give rise to transfection notwithstanding the double positive charge of the molecule. On the other hand, DSC measurements on synthetic membranes show that the compounds with the shortest spacers (three and four methylene groups) practically do not interact with the 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine membrane, while compounds P16-8 and, particularly, P16-12 induce the formation of surfactant-rich and surfactant-poor domains in the membrane, without showing any peculiarity for compound P16-4. This could suggest that the mechanisms involved in the interaction with the model membrane and in gene delivery are substantially different and could strike a blow for an endocytosis mechanism for the internalization in the cell of the DNA nanoparticles.

New gluconamide-type cationic surfactants: Interactions with DNA and lipid membranes.

New linear cationic surfactants - 2-(alkyldimethylammonio)ethylgluconamide bromides, denoted as CnGAB, n=10, 12, 14 and 16 - were synthesized from natural resources and characterized with respect to their potential as gene-delivery agents in gene therapy applications. Interactions with plasmid DNA and with model membranes were studied both experimentally and theoretically. The compounds with n=12, 14 and 16 show exponentially increasing ability to fully condense DNA. C16GAB condenses DNA at 1:1 surfactant to nucleotide molar ratio. Furthermore, CnGABs interact with model membrane, slightly lowering the temperature of the main phase transition Tm of the DPPC bilayer. C10GAB is found to interact only at the membrane surface. C16GAB reduces Tm less than C12GAB and C14GAB, and forms domains in the bilayer at the surfactant/DPPC molar ratio of 0.1 and higher. The results suggest that C16GAB can be a promising candidate for building gene-delivery carrier systems.