Lectin functionalized nanocarriers for gene delivery

Gastrointestinal dysmotility in rodent models of Parkinson's disease

Multiple studies describe prodromal, nonmotor dysfunctions that affect the quality of life of patients who subsequently develop Parkinson's disease (PD). These prodromal dysfunctions comprise a wide array of autonomic issues, including severe gastrointestinal (GI) motility disorders such as dysphagia, delayed gastric emptying, and chronic constipation. Indeed, strong evidence from studies in humans and animal models suggests that the GI tract and its neural, mainly vagal, connection to the central nervous system (CNS) could have a major role in the etiology of PD. In fact, misfolded α-synuclein aggregates that form Lewy bodies and neurites, i.e., the histological hallmarks of PD, are detected in the enteric nervous system (ENS) before clinical diagnosis of PD. The aim of the present review is to provide novel insights into the pathogenesis of GI dysmotility in PD, focusing our attention on functional, neurochemical, and molecular alterations in animal models.

Lectin Purification through Affinity Chromatography Exploiting Macroporous Monolithic Adsorbents

Growing medical, engineering, biochemical, and biological interest has led to a steady pace of research and development into polymeric monolithic structures with densely interconnected pores for purifying bio compounds. Cryogels, which are generated by freezing a reactive polymerization mixture, are highlighted due to their versatility and low relative cost as macroporous, polymeric, monolithic adsorbents. The conversion of cryogels into affinity adsorbents is one possible alternative to their optimal application. Some of the most often utilized supports for immobilizing particular ligands are monolithic columns manufactured with epoxy radicals on their surfaces. The purification of biomolecules with a high degree of specificity, such as lectins and glycoproteins with an affinity for glycosylated groups, has garnered interest in the use of fixed non-traditional beds functionalized with ligands of particular interest. The interaction is both robust enough to permit the adsorption of glycoproteins and reversible enough to permit the dissociation of molecules in response to changes in the solution’s pH. When compared to other protein A-based approaches, this one has been shown to be more advantageous than its counterparts in terms of specificity, ease of use, and cost-effectiveness. Information on polymeric, macroporous, monolithic adsorbents used in the affinity chromatographic purification of lectins has been published and explored.

Efficient in vitro and in vivo docetaxel delivery mediated by pH-sensitive LPHNPs for effective breast cancer therapy

The present study was designed to develop pH-sensitive lipid polymer hybrid nanoparticles (pHS-LPHNPs) for specific cytosolic-delivery of docetaxel (DTX). The pHS-LPHNPs-DTX formulation was prepared by self-assembled nano-precipitation technique and characterized for zeta potential, particle size, entrapment efficiency, polydispersity index (PDI), and in vitro drug release. In vitro cytotoxicity of pHS-LPHNPs-DTX was assessed on breast cancer cells (MDA-MB-231 and MCF-7) and compared with DTX-loaded conventional LPHNPs and bare DTX. In vitro cellular uptake in MDA-MB-231 cell lines showed better uptake of pHS-LPHNPs. Further, a significant reduction in the IC₅₀ of pHS-LPHNPs-DTX against both breast cancer cells was observed. Flow cytometry results showed greater apoptosis in case of pHS-LPHNPs-DTX treated MDA-MB-231 cells. Breast cancer was experimentally induced in BALB/c female mice, and the in vivo efficacy of the developed pHS-LPHNPs formulation was assessed with respect to the pharmacokinetics, biodistribution in the vital organs (liver, kidney, heart, lungs, and spleen), percentage tumor burden, and survival of breast cancer-bearing animals. In vivo studies showed improved pharmacokinetic and target-specificity with minimum DTX circulation in the deep-seated organs in the case of pHS-LPHNPs-DTX compared to the LPHNPs-DTX and free DTX. Mice treated with pHS-LPHNPs-DTX exhibited a significantly lesser tumor burden than other treatment groups. Also, reduced distribution of DTX in the serum was evident for pHS-LPHNPs-DTX treated mice compared to the LPHNPs-DTX and free DTX. In essence, pHS-LPHNPs mediated delivery of DTX presents a viable platform for developing therapeutic-interventions against breast-cancer.

Biodegradable dendritic Boltorn™ nanoconstructs: A promising avenue for cancer theranostics

The family of Boltorn™ H40 dendrimers is an imperative subclass of hyperbranched biodegradable polymers (HBPs), which has received mounting attention as a result of its inimitable chemical, physical and biodegradable properties. These properties embrace three-dimensional dendrimeric nanoarchitecture to avert tanglement between polymer branches, adequate spatial cavities for increased encapsulation of guest molecules, good solubility as well as low viscosity to improve processability, and a huge number of surface functional groups for chemical manipulations. Similarly, low toxicity, non-immunogenicity, and natural biodegradation are significant and critical advantages in therapeutic applications as compared to other dendritic polymers. All these characteristics of Boltorn™ H40 are of pronounced importance for planning and developing advanced targeted cargo delivery carriers for cancer therapy. The present review highlights the applications of Boltorn™ H40 HBPs for the transport of chemotherapeutic agents to manage various types of cancers.

Parkinson disease and the gut: new insights into pathogenesis and clinical relevance

The classic view portrays Parkinson disease (PD) as a motor disorder resulting from loss of substantia nigra pars compacta dopaminergic neurons. Multiple studies, however, describe prodromal, non-motor dysfunctions that affect the quality of life of patients who subsequently develop PD. These prodromal dysfunctions comprise a wide array of gastrointestinal motility disorders including dysphagia, delayed gastric emptying and chronic constipation. The histological hallmark of PD - misfolded α-synuclein aggregates that form Lewy bodies and neurites - is detected in the enteric nervous system prior to clinical diagnosis, suggesting that the gastrointestinal tract and its neural (vagal) connection to the central nervous system could have a major role in disease aetiology. This Review provides novel insights on the pathogenesis of PD, including gut-to-brain trafficking of α-synuclein as well as the newly discovered nigro-vagal pathway, and highlights how vagal connections from the gut could be the conduit by which ingested environmental pathogens enter the central nervous system and ultimately induce, or accelerate, PD progression. The pathogenic potential of various environmental neurotoxicants and the suitability and translational potential of experimental animal models of PD will be highlighted and appraised. Finally, the clinical manifestations of gastrointestinal involvement in PD and medications will be discussed briefly.

H-type lectins - Structural characteristics and their applications in diagnostics, analytics and drug delivery

Lectins are ubiquitous carbohydrate-binding proteins that interact with sugar moieties in a highly specific manner. H-type lectins represent a new group of lectins that were identified in invertebrates. These lectins share structural homology and bind mainly to N-acetylgalactosamine (GalNAc). Recent structural studies on the H-type lectins provided a detailed description of the GalNAc-lectin interaction that is already exploited in a number of biomedical applications. Two members of the H-type lectin family, Helix pomatia agglutinin (HPA) and Helix aspersa agglutinin (HAA), have already been extensively used in many diagnostic tests due their ability to specifically recognize GalNAc. This ability is especially important because aberrant glycosylation patterns of proteins expressed by cancer cells contain GalNAc. In addition, H-type lectins were utilized in diagnostics of other non-cancer diseases and represent great potential as components of drug delivery systems. Here, we present an overview of the H-type lectins and their applications in diagnostics, analytics and drug delivery.

Ingestion of subthreshold doses of environmental toxins induces ascending Parkinsonism in the rat

Increasing evidence suggests that environmental neurotoxicants or misfolded α-synuclein generated by such neurotoxicants are transported from the gastrointestinal tract to the central nervous system via the vagus nerve, triggering degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and causing Parkinson's disease (PD). We tested the hypothesis that gastric co-administration of subthreshold doses of lectins and paraquat can recreate the pathology and behavioral manifestations of PD in rats. A solution containing paraquat + lectin was administered daily for 7 days via gastric gavage, followed by testing for Parkinsonian behavior and gastric dysmotility. At the end of the experiment, brainstem and midbrain tissues were analyzed for the presence of misfolded α-synuclein and neuronal loss in the SNpc and in the dorsal motor nucleus of the vagus (DMV). Misfolded α-synuclein was found in DMV and SNpc neurons. A significant decrease in tyrosine hydroxylase positive dopaminergic neurons was noted in the SNpc, conversely there was no apparent loss of cholinergic neurons of the DMV. Nigrovagally-evoked gastric motility was impaired in treated rats prior to the onset of parkinsonism, the motor deficits of which were improved by l-dopa treatment. Vagotomy prevented the development of parkinsonian symptoms and constrained the appearance of misfolded α-synuclein to myenteric neurons. These data demonstrate that co-administration of subthreshold doses of paraquat and lectin induces progressive, l-dopa-responsive parkinsonism that is preceded by gastric dysmotility. This novel preclinical model of environmentally triggered PD provides functional support for Braak's staging hypothesis of idiopathic PD.

Porphyra polysaccharide-derived carbon dots for non-viral co-delivery of different gene combinations and neuronal differentiation of ectodermal mesenchymal stem cells

In this study, multifunctional fluorescent carbon dots (CDs) were synthesized using a one-pot hydrothermal carbonization reaction, with the naturally-occurring porphyra polysaccharide (PPS) serving as a single carbon source for the first time and ethylenediamine (Ed) acting as the surface passivation agent. The resulting CDs enjoyed a high quantum yield (56.3%), excitation-dependent fluorescence, small size (<10 nm), spherical shape, uniform distribution, positive surface charge, low cytotoxicity and excellent ability to condense macromolecular plasmid DNA. The synthesized CDs were employed for neuronal induction from ectodermal mesenchymal stem cells for the first time via highly efficient non-viral gene delivery. The optimal combination of factors (Ascl1 and Brn2) was selected from seven different combinations out of Ascl1, Brn2 and Sox2 according to the expression of neuronal markers (Tuj1, Map2 and Tau). The results of qRT-PCR demonstrated that the CDs possessed a significantly higher transfection efficiency than the commercially available transfection reagents PEI (25 kDa) and Lipofectamine2000. Moreover, the CDs/pDNA nanoparticles exhibited more efficient neuronal differentiation of the EMSCs than the AT-RA-containing induction medium. Furthermore, the CDs/pDNA nanoparticles could enter cells via both caveolae- and clathrin-mediated endocytosis. Taken together, the natural polysaccharide PPS-derived CDs enriched the current application of CDs by employing the CDs as a novel non-viral gene carrier for neuronal differentiation of adult stem cells, which held great promise in tissue engineering and bioimaging.

Peptides for tumor-specific drug targeting: state of the art and beyond

This review outlines the most recent advances in peptide-mediated tumor-targeting and gives insight into the direction of the field.

Adding Functions to Biomaterial Surfaces through Protein Incorporation

The concept of biomaterials has evolved from one of inert mechanical supports with a long-term, biologically inactive role in the body into complex matrices that exhibit selective cell binding, promote proliferation and matrix production, and may ultimately become replaced by newly generated tissues in vivo. Functionalization of material surfaces with biomolecules is critical to their ability to evade immunorecognition, interact productively with surrounding tissues and extracellular matrix, and avoid bacterial colonization. Antibody molecules and their derived fragments are commonly immobilized on materials to mediate coating with specific cell types in fields such as stent endothelialization and drug delivery. The incorporation of growth factors into biomaterials has found application in promoting and accelerating bone formation in osteogenerative and related applications. Peptides and extracellular matrix proteins can impart biomolecule- and cell-specificities to materials while antimicrobial peptides have found roles in preventing biofilm formation on devices and implants. In this progress report, we detail developments in the use of diverse proteins and peptides to modify the surfaces of hard biomaterials in vivo and in vitro. Chemical approaches to immobilizing active biomolecules are presented, as well as platform technologies for isolation or generation of natural or synthetic molecules suitable for biomaterial functionalization.

Preparation and characterization of glycoprotein-resistant starch complex as a coating material for oral bioadhesive microparticles for colon-targeted polypeptide delivery

For effective oral delivery of polypeptide or protein and enhancement their oral bioavailability, a new resistant starch-glycoprotein complex bioadhesive carrier and an oral colon-targeted bioadhesive delivery microparticle system were developed. A glycoprotein, concanavalin A (Con A), was successfully conjugated to the molecules of resistant starch acetate (RSA), leading to the formation of resistant starch-glycoprotein complex. This Con A-conjugated RSA film as a coating material showed an excellent controlled-release property. In streptozotocin (STZ)-induced type II diabetic rats, the insulin-loaded microparticles coated with this Con A-conjugated RSA film exhibited good hypoglycemic response for keeping the plasma glucose level within the normal range for totally 44-52 h after oral administration with different insulin dosages. Oral glucose tolerance tests indicated that successive oral administration of these colon-targeted bioadhesive microparticles with insulin at a level of 50 IU/kg could achieve a hypoglycemic effect similar to that by injection of insulin at 35 IU/kg. Therefore, the potential of this new Con A-conjugated RSA film-coated microparticle system has been demonstrated to be capable of improving the oral bioavailability of bioactive proteins and peptides.

Cationic Polysaccharides in Gene Delivery

Approval of Glybera®, a gene therapy to treat lipoprotein lipase deficiency, by the European Union Marketing Authorization, and more than 1800 clinical trials in over 31 countries for the treatment of many incurable diseases, narrates the successful journey of gene therapy in the biomedical field. However, the undesired side effects of gene therapy using viral and other vectors have overshadowed the success story of gene therapy. Non-viral vectors, and more particularly cationic polysaccharides due to their non-toxicity, water solubility, biodegradability and excellent compatibility with body systems, provide an excellent alternative for gene delivery. This chapter highlights significant contributions made by cationic polysaccharides in gene delivery.

A promising gene delivery system developed from PEGylated MoS2 nanosheets for gene therapy

A new class of two-dimensional (2D) nanomaterial, transition metal dichalcogenides (TMDCs) such as MoS2, MoSe2, WS2, and WSe2 which have fantastic physical and chemical properties, has drawn tremendous attention in different fields recently. Herein, we for the first time take advantage of the great potential of MoS2 with well-engineered surface as a novel type of 2D nanocarriers for gene delivery and therapy of cancer. In our system, positively charged MoS2-PEG-PEI is synthesized with lipoic acid-modified polyethylene glycol (LA-PEG) and branched polyethylenimine (PEI). The amino end of positively charged nanomaterials can bind to the negatively charged small interfering RNA (siRNA). After detection of physical and chemical characteristics of the nanomaterial, cell toxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Polo-like kinase 1 (PLK1) was investigated as a well-known oncogene, which was a critical regulator of cell cycle transmission at multiple levels. Through knockdown of PLK1 with siRNA carried by novel nanovector, qPCR and Western blot were used to measure the interfering efficiency; apoptosis assay was used to detect the transfection effect of PLK1. All results showed that the novel nanocarrier revealed good biocompatibility, reduced cytotoxicity, as well as high gene-carrying ability without serum interference, thus would have great potential for gene delivery and therapy.

Enhanced transport of nanocage stabilized pure nanodrug across intestinal epithelial barrier mimicking Listeria monocytogenes

Ligand grafted nanoparticles have been shown to enhance drug transport across epithelium barrier and are expected to improve drug delivery. However, grafting of these ligands to the surface of pure nanodrug, i.e., nanocrystals (NCs), is a critical challenge due to the shedding of ligands along with the stabilizer upon high dilution or dissolving of the drug. Herein, a non-sheddable nanocage-like stabilizer was designed by covalent cross-linking of poly(acrylic acid)-b-poly(methyl acrylate) on drug nanocrystal surface, and a ligand, wheat germ agglutinin (WGA), was successfully anchored to the surface of itraconazole (ITZ) NCs by covalent conjugation to the nanocage (WGA-cage-NCs). The cellular study showed that large amount of WGA-cage-NCs were adhered to Caco-2 cell membrane, and invaded into cells, resulting in a higher drug uptake than that of ordinary NCs (ONCs). After oral administration to rats, WGA-cage-NC were largely accumulated on the apical side of epithelium cells, facilitating drug diffusing across epithelium barrier. Interestingly, WGA-cage-NCs were capable of invading rat intestinal villi and reaching to lamina propria by transcytosis across goblet cells, which behaved like a foodborne pathogen, Listeria monocytogenes. The WGA-cage-NCs showed an improved oral bioavailability, which was 17.5- and 2.41-folds higher than that of coarse crystals and ONCs, respectively. To our best knowledge, this may represent the first report that a functional ligand was successfully anchored to the surface of pure nanodrug by using a cage-like stabilizer, showing unique biological functions in gastrointestinal tract and having an important significance in oral drug delivery.

Surface modification of nonviral nanocarriers for enhanced gene delivery

Biomedical nanotechnology has given a new lease of life to gene therapy with the ever-developing and ever-diversifying nonviral gene delivery nanocarriers. These are designed to pass a series of barriers in order to bring their nucleic acid cargo to the right subcellular location of particular cells. For a given application, each barrier has its dedicated strategy, which translates into a physicochemical, biological and temporal identity of the nanocarrier surface. Different strategies have thus been explored to implement adequate surface identities on nanocarriers over time for systemic delivery. In that context, this review will mainly focus on organic nanocarriers, for which these strategies will be described and discussed.

Synthesis and evaluation of glyco-coated liposomes as drug carriers for active targeting in drug delivery systems

Novel sugar-conjugated cholesterols, β-Gal-, α-Man-, β-Man-, α-Fuc-, and β-Man-6P-S-β-Ala-Chol, were synthesized and incorporated into liposomes. In vitro experiments using the glyco-coated liposomes showed that the glyco-coated liposomes are efficiently taken up by cells expressing carbohydrate-binding receptors selectively. Glyco-coated liposomes are promising candidates for drug delivery vehicles.

Functional and biodegradable dendritic macromolecules with controlled architectures as nontoxic and efficient nanoscale gene vectors

Gene therapy has provided great potential to revolutionize the treatment of many diseases. This therapy is strongly relied on whether a delivery vector efficiently and safely directs the therapeutic genes into the target tissue/cells. Nonviral gene delivery vectors have been emerging as a realistic alternative to the use of viral analogs with the potential of a clinically relevant output. Dendritic polymers were employed as nonviral vectors due to their branched and layered architectures, globular shape and multivalent groups on their surface, showing promise in gene delivery. In the present review, we try to bring out the recent trend of studies on functional and biodegradable dendritic polymers as nontoxic and efficient gene delivery vectors. By regulating dendritic polymer design and preparation, together with recent progress in the design of biodegradable polymers, it is possible to precisely manipulate their architectures, molecular weight and chemical composition, resulting in predictable tuning of their biocompatibility as well as gene transfection activities. The multifunctional and biodegradable dendritic polymers possessing the desirable characteristics are expected to overcome extra- and intracellular obstacles, and as efficient and nontoxic gene delivery vectors to move into the clinical arena.

Polymeric micelles, a promising drug delivery system to enhance bioavailability of poorly water-soluble drugs

Oral administration is the most commonly used and readily accepted form of drug delivery; however, it is find that many drugs are difficult to attain enough bioavailability when administered via this route. Polymeric micelles (PMs) can overcome some limitations of the oral delivery acting as carriers able to enhance drug absorption, by providing (1) protection of the loaded drug from the harsh environment of the GI tract, (2) release of the drug in a controlled manner at target sites, (3) prolongation of the residence time in the gut by mucoadhesion, and (4) inhibition of efflux pumps to improve the drug accumulation. To explain the mechanisms for enhancement of oral bioavailability, we discussed the special stability of PMs, the controlled release properties of pH-sensitive PMs, the prolongation of residence time with mucoadhesive PMs, and the P-gp inhibitors commonly used in PMs, respectively. The primary purpose of this paper is to illustrate the potential of PMs for delivery of poorly water-soluble drugs with bioavailability being well maintained.