Interaction of mucins with bioinspired polymers and drug delivery particles

Mucins are glycoproteins with high molecular weight and an abundance of negatively charged oligosaccharide side chains, representing the main components in the mucous gels apart from water. Mucin structure consists of a flexible backbone (mainly serine and threonine residues) which serves as anchoring points for oligosaccharide side chains, and hydrophobic \u201cnaked domains\u201d enriched in cysteine residues. The latter can form inter-molecular bonds via disulphide links, promoting mucin association in solution. Therefore, mucins can establish adhesive interactions with particulates/biomacromolecules via electrostatic interactions, van der Waals forces, hydrophobic forces, hydrogen bonding, or chain entanglement. Mucosal drug delivery vehicles can either penetrate rapidly or establish prolonged contact. However, their development is of great challenge because little is still known about the interactions between mucin and other macromolecules. We are currently working on a comprehensive study of the interaction between mucin and macromolecules of interest for pharmaceutical developments by complementary techniques. To this scope, we employ biocompatible natural and synthetic polymers with different physical-chemical characteristics. Among them, linear polyamidoamines with amphoteric character are particularly interesting for their cyto-biocompatibility. It is indeed crucial to characterise such interactions not only in the bulk but also at the interface, since complexation between mucins and biomacromolecules takes place close to the cell membrane surface. Moreover, the strategy to overcome mucus barrier and achieve long retention time in the cell surface is to develop nano-agents which can effectively penetrate the mucus layer and accumulate at the epithelial surface. In this framework we present preliminary investigations in the bulk by small angle x-ray scattering (SAXS) and at the solid-liquid interface by employing quartz crystal microbalance (QCM-D)

Model cell membrane interaction with a bioinspired amphoteric polymer

We present recent investigation by means of nanoscale techniques on biocompatible linear polyamidoamines with amphoteric character, namely AGMA1 and ARGO7. These polymers have been shown of extremely promising and already proved medical interest, comprising their strong protection actions against virus infection, mainly papilloma and herpes and the extremely low toxicity of their DNA complexes, with respect to other used polymers such as PEI and protamine, applied in nanovector design for gene delivery. Our studies focus on the most important of these polymers, AGMA1, a prevailingly cationic 4-aminobutylguanidine-deriving PAA, whose mechanism of action is so far not fully understood. The current understanding is that its interaction with cell surfaces by means of glycosaminoglycans (HSPG) has a major role in its protective action against viruses. Yet, AGMA1 is active also against HPV-31, whose attachment does not appear to be dependent on HSPG. HPV-31, whose attachment does not appear to be dependent on HSPG. Therefore, AGMA1 binds other (as yet unidentified) receptors on the cell surface. As the known recipient is the HS carbohydrate moiety, other sugars rich membrane components have been proposed as probable AGMA1 target. Therefore, to shed a light on the mechanism of interaction of the polymer with sugar containing biologically relevant molecules, not HS, we have investigated AGMA1 in interaction with glycophyngolipids, Specifically, we studied multicomponent symmetric vesicles enriched in ganglioside GM1 built to mimic biological membrane domains, in the presence of AGMA1, At physiological pH, electrostatic effects should be the relevant interactions between GM1 and AGMA1. Taking advantage of the same mechanism we investigated the possibility of building lipid based core-shell particles to vehiculate AGMA1/siRNA complexes. Moreover, since it is probable that AGMA1 interacts with the barrier of mucus which cover the involved tissue we have extended our investigations also to mucin, constituting the biological barrier to the target tissues of the medical application of the polymers

Model cell membrane interaction with a bioinspired amphoteric polymer

We present recent investigation by means of nanoscale techniques on biocompatible linear polyamidoamines with amphoteric character, namely AGMA1 and ARGO7. These polymers have been shown of extremely promising and already proved medical interest, comprising their strong protection actions against virus infection, mainly papilloma and herpes and the extremely low toxicity of their DNA complexes, with respect to other used polymers such as PEI and protamine, applied in nanovector design for gene delivery. Our studies focus on the most important of these polymers, AGMA1, a prevailingly cationic 4-aminobutylguanidine-deriving PAA, whose mechanism of action is so far not fully understood. The current understanding is that its interaction with cell surfaces by means of glycosaminoglycans (HSPG) has a major role in its protective action against viruses. Yet, AGMA1 is active also against HPV-31, whose attachment does not appear to be dependent on HSPG. HPV-31, whose attachment does not appear to be dependent on HSPG. Therefore, AGMA1 binds other (as yet unidentified) receptors on the cell surface. As the known recipient is the HS carbohydrate moiety, other sugars rich membrane components have been proposed as probable AGMA1 target. Therefore, to shed a light on the mechanism of interaction of the polymer with sugar containing biologically relevant molecules, not HS, we have investigated AGMA1 in interaction with glycophyngolipids, Specifically, we studied multicomponent symmetric vesicles enriched in ganglioside GM1 built to mimic biological membrane domains, in the presence of AGMA1, At physiological pH, electrostatic effects should be the relevant interactions between GM1 and AGMA1. Taking advantage of the same mechanism we investigated the possibility of building lipid based core-shell particles to vehiculate AGMA1/siRNA complexes. Moreover, since it is probable that AGMA1 interacts with the barrier of mucus which cover the involved tissue we have extended our investigations also to mucin, constituting the biological barrier to the target tissues of the medical application of the polymers

Effects of Cognitive Remediation on Cognition, Metacognition, and Social Cognition in Patients With Schizophrenia

We aimed to evaluate in a sample of outpatients with schizophrenia (SCZ) the effectiveness of a cognitive remediation (CR) program (through the use of the Cogpack software) [computer-assisted CR (CACR)] in addition to standard therapy on cognitive outcomes as compared with that in a control active group (CAG) and to highlight a possible effect on social cognition (SC), metacognition, symptomatology, and real-world functioning. Of the 66 subjects enrolled, 33 were allocated to CACR and 33 to the CAG. Twenty-three patients in the CACR group and 25 subjects in the CAG completed at least 80% of the 48 prescribed CACR sessions, performed twice a week, for a total of 24 weeks of treatment. A significant time × group interaction was evident, suggesting that patients undergoing CACR intervention improved in specific metacognitive sub-functions (understanding others' mind and mastery), some cognitive domains (verbal learning processing speed, visual learning, reasoning, and problem solving) (h(2) = 0.126), depressive symptoms, SC, awareness of symptoms, and real-world functioning domains (community activities and interpersonal relationships) more significantly than did patients undergoing CAG. The most noticeable differential improvement between the two groups was detected in two metacognitive sub-functions (understanding others' mind and mastery), in verbal learning, in interpersonal relationship, and in depressive symptomatology, achieving large effect sizes. These are encouraging findings in support of the possible integration of CACR in rehabilitation practice in the Italian mental health services

Pharmacological treatment for social cognition: Current evidence

Cognitive impairment is currently considered a core feature of schizophrenia (SZ) and is gaining attention as a fundamental therapeutic target. Standard treatment for SZ involves the use of antipsychotics that are successfully used to control positive symptoms and disorganized behaviour. However, it is still unclear whether they are effective on social cognition (SC) impairment. Furthermore, different medications are currently being studied to improve SC in patients with SZ. A literature search on this topic was conducted using the PubMed database. All kinds of publications (i.e., reviews, original contributions and case reports) written in English and published in the last 15 years were included. The aim of our literature review is to draw a picture of the current state of the pharmacological treatment of SC impairment in SZ

Building a biomimetic membrane for neutron reflectivity investigation : complexity, asymmetry and contrast

The preparation and investigation of model membranes is deserving growing interest both for the physics of complex systems, and for biology. The need of simplified models should preserve mimicking the qualifying characteristics of biological membranes, and keep non-invasive and detailed description. As a main feature, biological membranes are non-homogeneous in the disposition of components, both in the lateral and in the transverse direction. We prepared asymmetric supported membranes containing GM1 ganglioside in biomimetic proportion according to different protocols. Then, we studied their internal structure by neutron reflectometry, providing few-Angstrom sensitivity in the cross direction meanwhile avoiding radiation damage. This technique can also be profitably applied to study interactions at the membrane surface. The best protocol has proven to be the Langmuir-Blodgett/Langmuir-Schaefer depositions. Notably, also the simpler and most accessible protocol of vesicle fusion was found to be suitable for straightforward and good quality deposition of compositionally asymmetric membranes

Decoration of nanovesicles with pH (low) insertion peptide (pHLIP) for targeted delivery

Acidity at surface of cancer cells is a hallmark of tumor microenvironments, which does not depend on tumor perfusion, thus it may serve as a general biomarker for targeting tumor cells. We used the pH (low) insertion peptide (pHLIP) for decoration of liposomes and niosomes. pHLIP senses pH at the surface of cancer cells and inserts into the membrane of targeted cells, and brings nanomaterial to close proximity of cellular membrane. DMPC liposomes and Tween 20 or Span 20 niosomes with and without pHLIP in their coating were fully characterized in order to obtain fundamental understanding on nanocarrier features and facilitate the rational design of acidity sensitive nanovectors. The samples stability over time and in presence of serum was demonstrated. The size, ζ-potential, and morphology of nanovectors, as well as their ability to entrap a hydrophilic probe and modulate its release were investigated. pHLIP decorated vesicles could be useful to obtain a prolonged (modified) release of biological active substances for targeting tumors and other acidic diseased tissues

Polymeric micelles in drug delivery: An insight of the techniques for their characterization and assessment in biorelevant conditions

Polymeric micelles, i.e. aggregation colloids formed in solution by self-assembling of amphiphilic polymers, represent an innovative tool to overcome several issues related to drug administration, from the low water-solubility to the poor drug permeability across biological barriers. With respect to other nanocarriers, polymeric micelles generally display smaller size, easier preparation and sterilization processes, and good solubilization properties, unfortunately associated with a lower stability in biological fluids and a more complicated characterization. Particularly challenging is the study of their interaction with the biological environment, essential to predict the real in vivo behavior after administration. In this review, after a general presentation on micelles features and properties, different characterization techniques are discussed, from the ones used for the determination of micelles basic characteristics (critical micellar concentration, size, surface charge, morphology) to the more complex approaches used to figure out micelles kinetic stability, drug release and behavior in the presence of biological substrates (fluids, cells and tissues). The techniques presented (such as dynamic light scattering, AFM, cryo-TEM, X-ray scattering, FRET, symmetrical flow field-flow fractionation (AF4) and density ultracentrifugation), each one with their own advantages and limitations, can be combined to achieve a deeper comprehension of polymeric micelles in vivo behavior. The set-up and validation of adequate methods for micelles description represent the essential starting point for their development and clinical success