Sustained delivery of BSA/HSA from biocompatible plant cellulose nanocrystals for in vitro cholesterol release from endothelial cells

Interactions between proteins and cellulose in a liquid crystalline media: Design of a droplet based experimental platform

Model systems are needed to provide controlled environment for the understanding of complex phenomena. Interaction between polysaccharides and proteins in dense medium are involved in numerous complex systems such as biomass conversion or plant use for food processing or biobased materials. In this work, cellulose nanocrystals (CNCs) were used to study proteins in a dense and organized cellulosic environment. This environment was designed within microdroplets using a microfluidic setup, and applied to two proteins, bovine serum albumin (BSA) and a GH7 endoglucanase, relevant to food and plant science, respectively. The CNC at 56.5 g/L organized in liquid crystalline structure and the distribution of the proteins was probed using synchrotron deep-UV radiation. The proteins were homogeneously distributed throughout the volume, but BSA significantly disturbed the droplet global organization, preferring partition in hydrophilic external micelles. In contrast, GH7 partitioned with the CNCs showing stronger non-polar interaction but without disruption of the system organization. Such results pave the road for the development of more complex polysaccharides - proteins in-vitro models.

Does Better Post-Thaw Motility of Dog Sperm Frozen with CLC Mean Better Zona Pellucida Binding Ability?

Even though the search for methods improving cryopreservation of canine spermatozoa led to an improvement of post-thaw quality, fertilizing results after insemination with frozen-thawed semen are still not satisfying. In this study, we focused on modification of spermatozoa membrane fluidity and investigated whether kinematic parameters as assessed by computer-assisted semen analyzer (CASA) can be improved. The primary aim of our study was to investigate whether the use of cholesterol-loaded cyclodextrins (CLC; 0.5 mg, 1 mg, 2 mg) and 2-Hydroxypropyl-ß-cyclodextrin (HBCD; 1 mg) positively influence capacitation status as examined by tyrosinphosphorylation, cholesterol efflux and zona binding assay (ZBA) of spermatozoa. The use of 0.5 mg of CLC increased the percentage of motile, progressive and rapid spermatozoa compared to the control. Addition of HBCD decreased motility and progressive motility of spermatozoa and the population with rapid movement in comparison to the control. The percentage of live spermatozoa without efflux of cholesterol compared to the control was increased when extender with 0.5 mg of CLC was used. There was no change in capacitation status. The zona binding ability of spermatozoa was significantly lower in the group with 0.5 mg of CLC than in the control. In conclusion, these results suggest that improvement of kinematic parameters does not necessarily coincide with better zona pellucida binding ability of spermatozoa.

Flavour compounds affect protein structure: The effect of methyl anthranilate on bovine serum albumin conformation

This study aims to understand possible effects of flavour compounds on the structure and conformation of endogenous proteins. Using methyl anthranilate (a grape flavour compound added to drinks, confectionery, and vape-liquids) and bovine serum albumin (BSA, a model serum protein) we designed experimental investigations using analytical ultracentrifugation, size exclusion chromatography small angle X-ray scattering, and fluorescence spectroscopy to reveal that methyl anthranilate spontaneously binds to BSA (ΔG°, ca. -21 KJ mol^-1) which induces a conformational compactness (ca. 10 %) in the monomer structure. Complementary molecular modelling and dynamics simulations suggested the binding occurs at Sudlow II of BSA via establishment of hydrogen bonds with arginine⁴⁰⁹, lysine⁴¹³ and serine⁴⁸⁸ leading to an increased conformational order in domains IA, IIB and IIIB. This work aims to set the foundation for future research on flavour-protein interactions and offer new sets of opportunities for understanding the effects of small compounds on protein structure.

Nanocellulose, a versatile platform: From the delivery of active molecules to tissue engineering applications

Nanocellulose, a biopolymer, has received wide attention from researchers owing to its superior physicochemical properties, such as high mechanical strength, low density, biodegradability, and biocompatibility. Nanocellulose can be extracted from wide range of sources, including plants, bacteria, and algae. Depending on the extraction process and dimensions (diameter and length), they are categorized into three main types: cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and bacterial nanocellulose (BNC). CNCs are a highly crystalline and needle-like structure, whereas CNFs have both amorphous and crystalline regions in their network. BNC is the purest form of nanocellulose. The nanocellulose properties can be tuned by chemical functionalization, which increases its applicability in biomedical applications. This review highlights the fabrication of different surface-modified nanocellulose to deliver active molecules, such as drugs, proteins, and plasmids. Nanocellulose-mediated delivery of active molecules is profoundly affected by its topographical structure and the interaction between the loaded molecules and nanocellulose. The applications of nanocellulose and its composites in tissue engineering have been discussed. Finally, the review is concluded with further opportunities and challenges in nanocellulose-mediated delivery of active molecules.

Ultrasound-targeted simvastatin-loaded microbubble destruction promotes OA cartilage repair by modulating the cholesterol efflux pathway mediated by PPARγ in rabbits

Aims

To evaluate the effect of ultrasound-targeted simvastatin-loaded microbubble destruction (UTMD_SV) for alleviation of the progression of osteoarthritis (OA) in rabbits through modulation of the peroxisome proliferator-activated receptor (PPARγ).

Methods

In vitro, OA chondrocytes were treated with ultrasound (US), US-targeted microbubble destruction (UTMD), simvastatin (SV), and UTMD_SV on alternate days for four weeks. Chondrocytes were also treated with PPARγ inhibitor, PPARγ inhibitor+ UTMD_SV, and UTMD_SV. The cholesterol efflux rate and triglyceride levels were measured using an assay kit and oil red O staining, respectively. In vivo, the OA rabbits were treated with a single intra-articular injection of UTMD, SV, and UTMD_SV every seven days for four weeks. Cartilage histopathology was assessed by safranin-O staining and the Mankin score. Total cholesterol (TC) and high-density lipoprotein-cholesterol (HDL-C) in rabbit knee synovial fluid were detected by enzyme-marker assay. Aggrecan, collagen II, and PPARγ expression levels were analyzed by Western blotting (WB).

Results

In vitro, UTMD_SV significantly increased the cholesterol efflux rate and aggrecan, collagen II, and PPARγ levels in OA chondrocytes; these effects were blocked by the PPARγ inhibitor. In vivo, UTMD_SV significantly increased aggrecan, collagen II, PPARγ, and HDL-C levels, while TC levels and Mankin scores were decreased compared with the UTMD, SV, OA, and control groups.

Conclusion

UTMD_SV promotes cartilage extracellular matrix synthesis by modulating the PPARγ-mediated cholesterol efflux pathway in OA rabbits.

Cite this article: Bone Joint Res 2021;10(10):693–703.

Multifunctional Gold Nanoparticle-Conjugated Cellulose Nanoonions Alleviate Aβ42 Fibrillation-Induced Toxicity via Regulation of Oxidative Stress and Ion Homeostasis

Inhibition of hen egg white lysozyme (HEWL) and Aβ42 fibrillation have been established as the main models for the treatment of systemic lysozyme amyloidosis and Alzheimer's disease (AD), respectively. Several antiamyloidogenic nanomaterials have been developed over the period; however, their intracellular mechanism of action is still not well understood. In this context, plant-based, gold-conjugated, injectable, hydrophilic cellulose nanoonions (CNOs), viz., DH-CNO (∼60 ± 5 nm) and LC-CNO (∼55 ± 12 nm), were developed from their respective hydrophobic cellulose nanocrystals (DH-CNC and LC-CNC) using a single-step chemical template-mediated process. This unique nanocellulose architecture was chemically and morphologically characterized by various spectroscopic and microscopic techniques. Further, the different biophysical studies documented marked the inhibition/disintegration potential of gold-conjugated LC-CNO against HEWL and Aβ42 peptide aggregation. It was further observed that inhibition of protein fibrillation could be achieved within ∼10 min when the same materials were used under photoirradiation conditions. In vitro protein aggregation studies using HEK293 cells suggested that gold-conjugated LC-CNO could effectively reduce the cellular toxicity via regulation of oxidative stress and ion homeostasis. The outcome of the present study will help in designing cellulose-based novel functional nanochaperones against various neurodegenerative diseases.

Applications of serum albumins in delivery systems: Differences in interfacial behaviour and interacting abilities with polysaccharides

One of the major applications of Serum Albumins is their use as delivery systems for lipophilic compounds in biomedicine. Their biomedical application is based on the similarity with Human Serum Albumin (HSA), as a fully biocompatible protein. In general, Bovine Serum Albumin (BSA) is treated as comparable to its human homologue and used as a model protein for fundamental studies since it is available in high amounts and well understood. This protein can act as a carrier for lipophilic compounds or as protective shell in an emulsion-based vehicle. Polysaccharides are generally included in these formulations in order to increase the stability and/or applicability of the carrier. In this review, the main biomedical applications of Albumins as drug delivery systems are first presented. Secondly, the differences between BSA and HSA are highlighted, exploring the similarities and differences between these proteins and their interaction with polysaccharides, both in solution and adsorbed at interfaces. Finally, the use of Albumins as emulsifiers for emulsion-based delivery systems, concretely as Liquid Lipid Nanocapsules (LLNs), is revised and discussed in terms of the differences encountered in the molecular structure and in the interfacial properties. The specific case of Hyaluronic Acid is considered as a promising additive with important applications in biomedicine. The literature works are thoroughly discussed highlighting similarities and differences between BSA and HSA and their interaction with polysaccharides encountered at different structural levels, hence providing routes to control the optimal design of delivery systems.

Effects of phytochemicals on cellular signaling: reviewing their recent usage approaches

Most of the previous studies in last three decades report evidence of interactions between the different phytochemicals and the proteins involved in signal transduction pathways using in silico, in vitro, ex vivo, and in vivo analyses. However, extrapolation of these findings for clinical purposes has not been that fruitful. The efficacy of the phytochemicals in vivo studies is limited by parameters such as solubility, metabolic degradation, excretion, etc. Various approaches have now been devised to circumvent these limitations. Recently, chemical modification of the phytochemicals are demonstrated to reduce some of the limitations and improve their efficacy. Similar to traditional medicines several combinatorial phytochemical formulations have shown to be more efficient. Further, phytochemicals have been reported to be even more efficient in the form of nanoparticles. However, systematic evaluation of their efficacy, mode of action in pathway modulation, usage and associated challenges is required to be done. The present review begins with basic understanding of how signaling cascades regulate cellular response and the consequences of their dysregulation further summarizing the developments and problems associated with the dietary phytochemicals and also discuss recent approaches in strengthening these compounds in pharmacological applications. Only context relevant studies have been reviewed. Considering the limitations and scope of the article, authors do not claim inclusion of all the early and recent studies.

Inhibition of Glycation-Induced Aggregation of Human Serum Albumin by Organic-Inorganic Hybrid Nanocomposites of Iron Oxide-Functionalized Nanocellulose

Protein aggregation leads to the transformation of proteins from their soluble form to the insoluble amyloid fibrils and these aggregates get deposited in the specific body tissues, accounting for various diseases. To prevent such an aggregation, organic-inorganic hybrid nanocomposites of iron oxide nanoparticle (NP, ∼6.5-7.0 nm)-conjugated cellulose nanocrystals (CNCs) isolated from Syzygium cumini (SC) and Pinus roxburghii (PR) were chemically synthesized. Transmission electron microscopy (TEM) images of the nanocomposites suggested that the in situ-synthesized iron oxide NPs were bound to the CNC surface in a uniform and regular fashion. The ThT fluorescence assay together with 8-anilino-1-naphthalenesulfonic acid, Congo Red, and CD studies suggested that short fiber-based SC nanocomposites showed better inhibition as well as dissociation of human serum albumin aggregates. The TEM and fluorescence microscopy studies supported similar observations. Native polyacrylamide gel electrophoresis results documented dissociation of higher protein aggregates in the presence of the developed nanocomposite. Interestingly, the dissociated proteins retained their biological function by maintaining a high amount of α-helix content. The in vitro studies with HEK-293 cells suggested that the developed nanocomposite reduces aggregation-induced cytotoxicity by intracellular reactive oxygen species scavenging and maintaining the Ca2+ ion-channel. These results indicated that the hybrid organic-inorganic nanocomposite, with simultaneous sites for hydrophobic and hydrophilic interactions, tends to provide a larger surface area for nanocomposite-protein interactions, which ultimately disfavors the nucleation step for fibrillation for protein aggregates.

A review on versatile applications of blends and composites of CNC with natural and synthetic polymers with mathematical modeling

Cellulose is world's most abundant, renewable and recyclable polysaccharide on earth. Cellulose is composed of both amorphous and crystalline regions. Cellulose nanocrystals (CNCs) are extracted from crystalline region of cellulose. The most attractive feature of CNC is that it can be used as nanofiller to reinforce several synthetic and natural polymers. In this article, a comprehensive overview of modification of several natural and synthetic polymers using CNCs as reinforcer in respective polymer matrix is given. The immense activities of CNCs are successfully utilized to enhance the mechanical properties and to broaden the field of application of respective polymer. All the technical scientific issues have been discussed highlighting the recent advancement in biomedical and packaging field.

Recent advances in nanoengineering cellulose for cargo delivery

The recent decade has witnessed a growing demand to substitute synthetic materials with naturally-derived platforms for minimizing their undesirable footprints in biomedicine, environment, and ecosystems. Among the natural materials, cellulose, the most abundant biopolymer in the world with key properties, such as biocompatibility, biorenewability, and sustainability has drawn significant attention. The hierarchical structure of cellulose fibers, one of the main constituents of plant cell walls, has been nanoengineered and broken down to nanoscale building blocks, providing an infrastructure for nanomedicine. Microorganisms, such as certain types of bacteria, are another source of nanocelluloses known as bacterial nanocellulose (BNC), which benefit from high purity and crystallinity. Chemical and mechanical treatments of cellulose fibrils made up of alternating crystalline and amorphous regions have yielded cellulose nanocrystals (CNC), hairy CNC (HCNC), and cellulose nanofibrils (CNF) with dimensions spanning from a few nanometers up to several microns. Cellulose nanocrystals and nanofibrils may readily bind drugs, proteins, and nanoparticles through physical interactions or be chemically modified to covalently accommodate cargos. Engineering surface properties, such as chemical functionality, charge, area, crystallinity, and hydrophilicity, plays a pivotal role in controlling the cargo loading/releasing capacity and rate, stability, toxicity, immunogenicity, and biodegradation of nanocellulose-based delivery platforms. This review provides insights into the recent advances in nanoengineering cellulose crystals and fibrils to develop vehicles, encompassing colloidal nanoparticles, hydrogels, aerogels, films, coatings, capsules, and membranes, for the delivery of a broad range of bioactive cargos, such as chemotherapeutic drugs, anti-inflammatory agents, antibacterial compounds, and probiotics. SYNOPSIS: Engineering certain types of microorganisms as well as the hierarchical structure of cellulose fibers, one of the main building blocks of plant cell walls, has yielded unique families of cellulose-based nanomaterials, which have leveraged the effective delivery of bioactive molecules.