Influences of superfine-grinding and enzymolysis separately assisted with carboxymethylation and acetylation on the in vitro hypoglycemic and antioxidant activities of oil palm kernel expeller fibre

The synergistic effects of ultrafine grinding and enzymolysis (cellulase and Laccase hydrolysis) alone or combined with carboxymethylation or acetylation on the hypoglycemic and antioxidant activities of oil palm kernel fibre (OPKEF) were studied for the first time. After these synergistic modifications, the microstructure of OPKEF became more porous, and its soluble fibre and total polyphenols contents, and surface area were all improved (P < 0.05). Superfine-grinding and enzymolysis combined with carboxymethylation treated OPKEF exhibited the highest viscosity (13.9 mPa∙s), inhibition ability to glucose diffusion (38.18%), and water-expansion volume (3.58 mL∙g-1). OPKEF treated with superfine-grinding and enzymolysis combined with acetylation showed the highest surface hydrophobicity (50.93) and glucose adsorption capacity (4.53 μmol∙g-1), but a lower α-amylase-inhibition ability. Moreover, OPKEF modified by superfine-grinding and enzymolysis had the highest inhibiting activity against α-amylase (25.78%). Additionally, superfine-grinding and enzymolysis combined with carboxymethylation or acetylation both improved the content and antioxidant activity of OPEKF's bounding polyphenols (P < 0.05).

Chemical modification of hyaluronic acid as a strategy for the development of advanced drug delivery systems

Hyaluronic acid (HA) has emerged as a promising biopolymer for various biomedical applications due to its biocompatibility, biodegradability, and intrinsic ability to interact with cell surface receptors, making it an attractive candidate for drug delivery systems and tissue engineering. Chemical modification of HA has opened up versatile possibilities to tailor its properties, enabling the development of advanced drug delivery systems and biomaterials with enhanced functionalities and targeted applications. This review analyzes the strategies and applications of chemically modified HA in the field of drug delivery and biomaterial development. The first part of the review focuses on the different methods and functional groups used for the chemical modification of HA, highlighting the impact of these modifications on its physicochemical properties, degradation behavior and interactions with drugs. The second part of the review evaluates the use of chemically modified HA in the development of advanced biomedical materials including nano- and microparticles, hydrogels and mucoadhesive materials with tailored drug release profiles, site-specific targeting and stimuli-responsive behavior. Thus, the review consolidates the current advances and future perspectives in the field of chemical modification of HA, underscoring its immense potential to drive the development of advanced drug delivery systems and biomaterials with diverse biomedical applications.

Semisynthesis of new sulfated heterorhamnan derivatives obtained from green seaweed Gayralia brasiliensis and evaluation of their anticoagulant activity

Marine green algae produce sulfated polysaccharides with diverse structures and a wide range of biological activities. This study aimed to enhance the biotechnological potential of sulfated heterorhamnan (Gb1) from Gayralia brasiliensis by chemically modifying it for improved or new biological functions. Using controlled Smith Degradation (GBS) and O-alkylation with 3-chloropropylamine, we synthesized partially water-soluble amine derivatives. GBS modification increase sulfate groups (29.3 to 37.5 %) and α-l-rhamnose units (69.9 to 81.2 mol%), reducing xylose and glucose, compared to Gb1. The backbone featured predominantly 3- and 2-linked α-l-rhamnosyl and 2,3- linked α-l-rhamnosyl units as branching points. Infrared and NMR analyses confirmed the substitution of hydroxyl groups with aminoalkyl groups. The modified compounds, GBS-AHCs and GBS-AHK, exhibited altered anticoagulant properties. GBS-AHCs showed reduced effectiveness in the APTT assay, while GBS-AHK maintained a similar anticoagulant activity level to Gb1 and GBS. Increased nitrogen content and N-alkylation in GBS-AHCs compared to GBS-AHK may explain their structural differences. The chemical modification proposed did not enhance its anticoagulant activity, possibly due to the introduction of amino groups and a positive charge to the polymer. This characteristic presents new opportunities for investigating the potential of these polysaccharides in various biological applications, such as antimicrobial and antitumoral activities.

Polysaccharides in fruits: Biological activities, structures, and structure-activity relationships and influencing factors-A review

Fruits are a rich source of polysaccharides, and an increasing number of studies have shown that polysaccharides from fruits have a wide range of biological functions. Here, we thoroughly review recent advances in the study of the bioactivities, structures, and structure-activity relationships of fruit polysaccharides, especially highlighting the structure-activity influencing factors such as extraction methods and chemical modifications. Different extraction methods cause differences in the primary structures of polysaccharides, which in turn lead to different polysaccharide biological activities. Differences in the degree of modification, molecular weight, substitution position, and chain conformation caused by chemical modification can all affect the biological activities of fruit polysaccharides. Furthermore, we summarize the applications of fruit polysaccharides in the fields of pharmacy and medicine, foods, cosmetics, and materials. The challenges and perspectives for fruit polysaccharide research are also discussed.

Development of a highly stable, active small interfering RNA with broad activity against SARS-CoV viruses

Treatment options for COVID-19 remain limited. Here, we report the optimization of an siRNA targeting the highly conserved leader region of SARS-CoV-2. The siRNA was rendered nuclease resistant by the introduction of modified nucleotides without loss of activity. Importantly, the siRNA also retained its inhibitory activity against the emerged omicron sublineage variant BA.2, which occurred after the siRNA was designed and is resistant to other antiviral agents such as antibodies. In addition, we show that a second highly active siRNA designed against the viral 5'-UTR can be applied as a rescue molecule, to minimize the spread of escape mutations. We therefore consider our siRNA-based molecules to be promising broadly active candidates for the treatment of current and future SARS-CoV-2 variants.

Viral nanoparticles: Current advances in design and development

Viral nanoparticles (VNPs) are self-assembling, adaptable delivery systems for vaccines and other therapeutic agents used in a variety of biomedical applications. The potential of viruses to invade and infect various hosts and cells renders them suitable as potential nanocarriers, possessing distinct functional characteristics, immunogenic properties, and improved biocompatibility and biodegradability. VNPs are frequently produced through precise genetic or chemical engineering, which involves adding diverse sequences or functional payloads to the capsid protein (CP). Several spherical and helical plant viruses, bacteriophages, and animal viruses are currently being used as VNPs, or non-infectious virus-like particles (VLPs). In addition to their broad use in cancer therapy, vaccine technology, diagnostics, and molecular imaging, VNPs have made important strides in the realms of tissue engineering, biosensing, and antimicrobial prophylaxis. They are also being used in energy storage cells due to their binding and piezoelectric properties. The large-scale production of VNPs for research, preclinical testing, and clinical use is fraught with difficulties, such as those relating to cost-effectiveness, scalability, and purity. Consequently, many plants- and microorganism-based platforms are being developed, and newer viruses are being explored. The goal of the current review is to provide an overview of these advances.

Properties and synergistic effects of a nonionic backbone and aminoalkyl modified nucleosides in RNAs

In this study, we report the synthesis of two formacetal (FA)-linked dimer building blocks, namely 2'-O-methyluridyl-2'-O-methyluridine and 2'-O-methyluridyl-2'-O-aminoethyluridine. We utilize the former dimer in combination with (S)-5'-C-aminopropyl-2'-O-methylnucleosides (5'-APs) as a neutral trimer unit, and the latter dimer as a cationic unit. Double-stranded RNA containing the neutral trimer unit exhibits greater stability compared to the cationic unit and maintains nuclease stability in a serum-containing buffer. Furthermore, this unit appears to establish additional hydrogen bonds with complementary bases, as supported by modeling simulations and mismatch melting temperature assays. Importantly, siRNAs modified with this unit enhance RNA interference activity in cultured cells. These findings suggest that the trimer unit holds promise for therapeutic siRNAs.

Lignin derivatives-based hydrogels for biomedical applications

Recently, numerous studies have been conducted on renewable polymers derived from different natural sources, exploring their suitability for diverse biomedical applications. Lignin as one of the main components of lignocellulosic has garnered significant attention as a promising alternative to petroleum-based polymers. This interest is primarily due to its cost-effectiveness, biocompatibility, eco-friendly nature, as well as its antioxidant and antimicrobial properties. These characteristics could be more beneficial when incorporating lignin into the formulation of value-added products. Although lignin has a chemical structure that is suitable for various applications, these characteristics require modifications to guarantee that the resultant materials display the desired biological, chemical, and physical properties when applied in the creation of biodegradable hydrogels, particularly for biomedical purposes. This study delineates the recent modification approaches that have been employed in the creation of lignin-based hydrogels. These strategies encompass both chemical and physical interactions with other polymers. Additionally, this review encompasses an examination of the current applications of lignin hydrogels, spanning their use as scaffolds for tissue engineering, carriers for pharmaceuticals, materials for wound dressings and biosensors, and elements in flexible and wearable electronics. Finally, we delve into the challenges and constraints associated with these materials, discuss the necessary steps required to attain the appropriate properties for the development of innovative lignin-based hydrogels, and derive conclusions based on the presented findings.

A review of recent developments in kenaf fiber/polylactic acid composites research

Kenaf fiber has recently garnered exponential interest as reinforcement in composite materials across diverse industries owing to its superior mechanical attributes, ease of manufacture, and inherent biodegradability. In the discourse of this review, various methods of manufacturing kenaf/Polylactic acid (PLA) composites have been discussed meticulously, as delineated in recently published scientific literatures. This paper delves into the chemical modification of kenaf fiber, examining its consequential impact on tensile strength and thermal stability of the kenaf/PLA composites. Further, this review illuminates the role of innovative 3D printing techniques and fiber orientation in augmenting the mechanical robustness of the kenaf/PLA composites. Simultaneously, recent insightful explorations into the acoustic properties of the kenaf/PLA composites, underscoring their potential as sustainable alternative to conventional materials have been reviewed. Serving as a comprehensive repository of knowledge, this review paper holds immense value for researchers aiming to utilize the capabilities of kenaf fiber reinforced PLA composites.

Impact of chemical modifications on the antimicrobial and hemolytic activity of helical amphipathic peptide Lasioglossin LL-III

Insect venom is abundant in potential antimicrobial peptides (AMPs), which can serve as novel alternatives to conventional antibiotics. Among them, Lasioglossin III LL-III) is a promising candidate with a broad spectrum against many fungi strains and both types of bacteria, whereas almost non-toxic to red blood cells. Many chemical approaches have been recently applied to improve its pharmacological properties and provide useful information regarding structure-activity relationships. Hence, this review focused on highlighting the lesson learned from each modification and supporting the future design of potent, selective, and metabolically stable AMPs.

Development of nucleic acid medicines based on chemical technology

Oligonucleotide-based therapeutics have attracted attention as an emerging modality that includes the modulation of genes and their binding proteins related to diseases, allowing us to take action on previously undruggable targets. Since the late 2010s, the number of oligonucleotide medicines approved for clinical uses has dramatically increased. Various chemistry-based technologies have been developed to improve the therapeutic properties of oligonucleotides, such as chemical modification, conjugation, and nanoparticle formation, which can increase nuclease resistance, enhance affinity and selectivity to target sites, suppress off-target effects, and improve pharmacokinetic properties. Similar strategies employing modified nucleobases and lipid nanoparticles have been used for developing coronavirus disease 2019 mRNA vaccines. In this review, we provide an overview of the development of chemistry-based technologies aimed at using nucleic acids for developing therapeutics over the past several decades, with a specific emphasis on the structural design and functionality of chemical modification strategies.

Plant type II arabinogalactan: Structural features and modification to increase functionality

Type II arabinogalactans (AGs) are a highly diverse class of plant polysaccharides generally encountered as the carbohydrate moieties of certain extracellular proteoglycans, the so-called arabinogalactan-proteins (AGPs), which are found on plasma membranes and in cell walls. The basic structure of type II AG is a 1,3-β-D-galactan main chain with 1,6-β-D-galactan side chains. The side chains are further decorated with other sugars such as α-l-arabinose and β-d-glucuronic acid. In addition, AGs with 1,6-β-D-galactan as the main chain, which are designated as 'type II related AG' in this review, can also be found in several plants. Due to their diverse and heterogenous features, the determination of carbohydrate structures of type II and type II related AGs is not easy. On the other hand, these complex AGs are scientifically and commercially attractive materials whose structures can be modified by chemical and biochemical approaches for specific purposes. In the current review, what is known about the chemical structures of type II and type II related AGs from different plant sources is outlined. After that, structural analysis techniques are considered and compared. Finally, structural modifications that enhance or alter functionality are highlighted.

Review: Application of chitosan and its derivatives in medical materials

Chitin is a natural polymeric polysaccharide extracted from marine crustaceans, and chitosan is obtained by removing part of the acetyl group (usually more than 60 %) in chitin's structure. Chitosan has attracted wide attention from researchers worldwide due to its good biodegradability, biocompatibility, hypoallergenic and biological activities (antibacterial, immune and antitumor activities). However, research has shown that chitosan does not melt or dissolve in water, alkaline solutions and general organic solvents, which greatly limits its application range. Therefore, researchers have carried out extensive and in-depth chemical modification of chitosan and prepared a variety of chitosan derivatives, which have expanded the application field of chitosan. Among them, the most extensive research has been conducted in the pharmaceutical field. This paper summarizes the application of chitosan and chitosan derivatives in medical materials over the past five years.

Preparation of Chemically Modified DNA Library for SELEX via Incorporation of CLB-dUTP in Primer Extension Reaction

Aptamers are single-stranded DNA or RNA molecules which bind with high specificity to the molecular target for which they have been selected. Through a number of unnatural modifications, the diversity of interactions available for this class of molecules can be greatly expanded, potentially leading to better binding properties. Herein we describe a method to prepare an initial chemically modified DNA library for SELEX. It comprises the synthesis of a modified nucleotide in the CuAAC reaction and its purification by an adapted HPLC method. Subsequent stage is the incorporation of the prepared modified nucleotide into a DNA library in a primer extension reaction and a quick and easy method of its purification using an electroelution device. This allows the recovery of the resulting chemically modified ssDNA library with high efficiency to kick off the aptamer selection process.

MS1-Based Data Analysis Approaches for FFPE Tissue Imaging of Endogenous Peptide Ions by Mass Spectrometry Histochemistry (MSHC)

Ambiguous reports in the literature exist regarding the use and usefulness of formalin-fixed paraffin-embedded (FFPE) tissues in mass spectrometry imaging (MSI). Especially for the study of endogenous (non-tryptic) peptides, several studies have concluded that MSI on archived FFPE tissue bank samples is virtually impossible. We here illustrate that by employing a variant of MSI, called mass spectrometry histochemistry (MSHC), biomolecular tissue localization data are obtained that unequivocally comprise endogenous peptides. We here discuss different informatics steps in a data analysis workflow to help filter peptide-related features out of large and complex datasets generated by atmospheric pressure matrix-assisted laser desorption/ionization high-resolution (Orbitrap mass analyzer) MSHC. These include, in addition to accurate mass measurements, Kendrick mass defect filtering and isotopic distribution scrutiny.

Chemical modifications in the structure of marine polysaccharide as serviceable food processing and preservation assistant: A review

Marine polysaccharides are a kind of natural polysaccharides which isolated and extracted from marine organisms. Now some marine polysaccharides, such as chitosan, sodium alginate and agar, have been proven to exhibit antibacterial, antioxidant functions and biocompatibility, which are often used to preserve food or improve the physicochemical properties of food. However, they still have the defects of unsatisfactory preservation effect and biological activity, which can be remedied by its modification. Chemical modification is the most effective of all modification methods. The advances in common chemical modification methods of chitosan, sodium alginate, agar and other marine polysaccharides and research progress of modified products in food processing and preservation were summarized, and the influence of additional reaction conditions on the existence of chemical modification sites of polysaccharides was discussed. The modification of functional groups in natural marine polysaccharides leads to the change of molecular structure, which can improve the physical, chemical and biological properties of marine polysaccharides. Chemically modified products have been used in various fields of food applications, such as food preservatives, food additives, food packaging, and food processing aids. In general, chemical modification has excellent potential for food processing and preservation, which can improve the function of marine polysaccharides.

Cytotoxic activity of several ent-kaurane derivatives of atractyligenin. Synthesis of unreported diterpenic skeleton by chemical rearrangement

Atractyloside, carboxyatractyloside, their aglycon atractyligenin, and several synthetic derivatives were tested and found to be active against a panel of human tumor cell lines. Atractyligenin was subjected to oxidation, bromination, and elimination reactions, obtaining several compounds. A singular skeleton was synthesized by chemical rearrangement starting from 3β-bromo-2,15-diketoatractyligenin methyl ester. The synthesized compounds resulted active against all cell lines tested. In particular, 15-ketoatractyligenin methyl ester and 3β-bromo-2,15-diketoatractyligenin methyl ester resulted the most active with IC50 values of 0.427 and 0.723 μM against A375 melanoma cell line. Excellent results were also obtained against the colon cancer cell line CaCo2, with slightly lower antiproliferative activity. An interesting extension of the study should be to analyze the atractyligenin derivatives also as target for human melanoma and human colon cancer cells.

Change of Heart: the Epitranscriptome of Small Non-coding RNAs in Heart Failure

Purpose of Review

Small non-coding RNAs regulate gene expression and are highly implicated in heart failure. Recently, an additional level of post-transcriptional regulation has been identified, referred to as the epitranscriptome, which encompasses the body of post-transcriptional modifications that are placed on RNA molecules. In this review, we summarize the current knowledge on the small non-coding RNA epitranscriptome in heart failure.

Recent Findings

With the rise of new methods to study RNA modifications, epitranscriptome research has begun to take flight. Over the past 3 years, the number of publications on the epitranscriptome in heart failure has significantly increased, and we expect many more highly relevant publications to come out over the next few years.

Summary

Currently, at least six modifications on small non-coding RNAs have been investigated in heart failure-relevant studies, namely N6-adenosine, N5-cytosine and N7-guanosine methylation, 2’-O-ribose-methylation, adenosine-to-inosine editing, and isomiRs. Their potential role in heart failure is discussed.

mRNA-based therapies: Preclinical and clinical applications

At the fundamental level, messenger RNA (mRNA)-based therapeutics involves the delivery of in vitro-transcribed (IVT) mRNA into the cytoplasm of a target cell, where it is translated into the desired protein. IVT mRNA presents various advantages compared to DNA and recombinant protein-based approaches that make it ideal for a broad range of therapeutic applications. IVT mRNA, which is translated in the cytoplasm after transfection into cells, can encode virtually any target protein. Notably, it does not enter the nucleus, which avoids its integration into the genome and the risk of insertional mutagenesis. The large-scale production of IVT mRNA is less complex than production of recombinant proteins, and Good Manufacturing Practice-compliant mRNA production is easily scalable, ideally poising mRNA for not only off-the-shelf, but more personalized treatment approaches. IVT mRNA's safety profile, pharmacokinetics, and pharmacodynamics, including its inherent immunostimulatory capacity, can be optimized for different therapeutic applications by harnessing a wide array of optimized sequence elements, chemical modifications, purification techniques, and delivery methods. The value of IVT mRNA was recently proved during the COVID-19 pandemic when mRNA-based vaccines outperformed the efficacy of established technologies, and millions of doses were rapidly deployed. In this review, we will discuss chemical modifications of IVT mRNA and highlight numerous preclinical and clinical applications including vaccines for cancer and infectious diseases, cancer immunotherapy, protein replacement, gene editing, and cell reprogramming.

Abundances of transfer RNA modifications and transcriptional levels of tRNA-modifying enzymes are sex-associated in mosquitoes

As carriers of multiple human diseases, understanding the mechanisms behind mosquito reproduction may have implications for remediation strategies. Transfer RNA (tRNA) acts as the adapter molecule of amino acids and are key components in protein synthesis. A critical factor in the function of tRNAs is chemical modifications which contribute to codon-anticodon interactions. Here, we provide an assessment of tRNA modifications between sexes for three mosquito species and examine the correlation of transcript levels underlying key proteins involved in tRNA modification. Thirty-three tRNA modifications were detected among mosquito species and most of these modifications are higher in females compared to males for three mosquito species. Analysis of previous male and female RNA-seq datasets indicated a similar increase in transcript levels of tRNA-modifying enzymes in females among six mosquito species, supporting our observed female enrichment of tRNA modifications. Tissues-specific expressional studies revealed higher transcript levels for tRNA-modifying enzymes in the ovaries for Aedes aegypti, but not male reproductive tissues. These studies suggest that tRNA modifications may be critical to reproduction in mosquitoes, representing a potential novel target for control through suppression of fecundity.

Mapping of the Chemical Modifications of rRNAs

Cellular RNAs, both coding and noncoding, contain several chemical modifications. Both ribose sugars and nitrogenous bases are targeted for these chemical additions. These modifications are believed to expand the topological potential of RNA molecules by bringing chemical diversity to otherwise limited repertoire. Here, using ribosomal RNA of yeast as an example, a detailed protocol for systematically mapping various chemical modifications to a single nucleotide resolution by a combination of Mung bean nuclease protection assay and RP-HPLC is provided. Molar levels are also calculated for each modification using their UV (254 nm) molar response factors that can be used for determining the amount of modifications at different residues in other RNA molecules. The chemical nature, their precise location and quantification of modifications will facilitate understanding the precise role of these chemical modifications in cellular physiology.

Meta-proteomic analysis of two mammoth's trunks by EVA technology and high-resolution mass spectrometry for an indirect picture of their habitat and the characterization of the collagen type I, alpha-1 and alpha-2 sequence

The recent paleoproteomic studies, including paleo-metaproteomic analyses, improved our understanding of the dietary of ancient populations, the characterization of past human diseases, the reconstruction of the habitat of ancient species, but also provided new insights into the phylogenetic relationships between extant and extinct species. In this respect, the present work reports the results of the metaproteomic analysis performed on the middle part of a trunk, and on the portion of a trunk tip tissue of two different woolly mammoths some 30,000 years old. In particular, proteins were extracted by applying EVA (Ethylene-Vinyl Acetate studded with hydrophilic and hydrophobic resins) films to the surface of these tissues belonging to two Mammuthus primigenus specimens, discovered in two regions located in the Russian Far East, and then investigated via a shotgun MS-based approach. This approach allowed to obtain two interesting results: (i) an indirect description of the habitat of these two mammoths, and (ii) an improved characterization of the collagen type I, alpha-1 and alpha-2 chains (col1a1 and col1a2). Sequence characterization of the col1a1 and col1a2 highlighted some differences between M. primigenius and other Proboscidea together with the identification of three (two for col1a1, and one for col1a2) potentially diagnostic amino acidic mutations that could be used to reliably distinguish the Mammuthus primigenius with respect to the other two genera of elephantids (i.e., Elephas and Loxodonta), and the extinct American mastodon (i.e., Mammut americanum). The results were validated through the level of deamidation and other diagenetic chemical modifications of the sample peptides, which were used to discriminate the "original" endogenous peptides from contaminant ones. The data have been deposited to the ProteomeXchange with identifier < PXD029558 > .

Recent advances of Sterculia gums uses in drug delivery systems

Trees of the genus Sterculia produce polysaccharide-rich exudates, such as karaya gum (Sterculia urens), chicha gum (Sterculia striata), and Sterculia foetida gum. These anionic biomaterials are biodegradable, with high viscosity, low toxicity, and gelling properties in aqueous media. According to these properties, they show promising applications as a polymer matrix for use in drug delivery systems. For this application, both the chemically modified and the unmodified polysaccharide are used. This review focuses on analyzing the state of the art of recent studies on the use of Sterculia gums in a variety of pharmaceutical forms, such as tablets, hydrogels, micro/nanoparticles, and mucoadhesive films. Sterculia gums-based delivery systems have potential to be explored for new drug delivery systems.

A Timeline of Perezone, the First Isolated Secondary Metabolite in the New World, Covering the Period from 1852 to 2020

This chapter covers a sesquiterpene quinone, commonly named perezone. This molecule is documented as the first secondary metabolite isolated in crystalline form in the New World in 1852. An introduction, with its structure, the IUPAC nomenclature, and the most recent physical and spectroscopic characterizations are firstly described initially. Alongside this, a timeline and scheme with summarized information of the history of this molecule is given including the "Códice Badiano de la Cruz, 1552, highlighting the year of its isolation culminating with information up to 2005. Subsequently, in a chronological order the most recent advances of the target molecule are included and organized in subsections covering the last 15-year period 2006-2020. Finally, recently submitted contributions from the laboratory of the authors are described. It is important to note that the details provided highlight the importance and relevance of perezone.

Strategies to identify and develop antiviral peptides

The emergence and re-emergence of viral pathogens capable of causing epidemics or pandemics pose a serious healthcare burden. Small molecule antivirals used in conventional therapy have given rise to the severe problem of viral resistance against them. Peptides are generally considered safe, effective and are less likely to induce viral resistance. Antiviral peptides can be identified from screening of phage display of combinational peptide libraries, peptide array libraries or designed against viral targets. Limitations of peptides such as bioavailability can be improved with chemical modifications. Nanotechnology can further improve the stability of peptides in systemic circulation and enhance the antiviral activity of peptides, making them an appealing therapeutic option.

Starch chemical modifications applied to drug delivery systems: From fundamentals to FDA-approved raw materials

Starch derivatives are versatile compounds that are widely used in the pharmaceutical industry. This article reviews the advances in the research on hydrophilic and hydrophobic starch derivatives used to develop drug delivery systems over the last ten years, specifically microparticles, nanoparticles, nanocrystals, hydrogels, and scaffolds using these materials. The fundamentals of drug delivery systems, regulatory aspects, and chemical modifications are also discussed, along with the synthesis of starch derivatives via oxidation, etherification, acid hydrolysis, esterification, and cross-linking. The chemical modification of starch as a means to overcome the challenges in obtaining solid dosage forms is also reviewed. In particular, dialdehyde starches are potential derivatives for direct drug attachment; carboxymethyl starches are used for drug encapsulation and release, giving rise to pH-sensitive devices through electrostatic interactions; and starch nanocrystals have high potential as hydrogel fillers to improve mechanical properties and control drug release through hydrophilic interactions. Starch esterification with alginate and acidic drugs could be very useful for site-specific, controlled release. Starch cross-linking with other biopolymers such as xanthan gum is promising for obtaining novel polyelectrolyte hydrogels with improved functional properties. Surface modification of starch nanoparticles by cross-linking and esterification reactions is a potential approach to obtain novel, smart solid dosages.

Tips for Successful lncRNA Knockdown Using Gapmers

Long noncoding RNAs (lncRNAs) are a recently discovered class of RNA that have diverse intracellular regulatory and structural roles. Because of their wide assortment of functions, lncRNAs can have varied distributions in the nucleus and/or cytoplasm of a cell. However, even though tens of thousands of human lncRNAs have been identified, currently less than 3% have empirically validated functions. RNA knockdown is now a relatively commonplace laboratory technique used to functionally characterize an RNA. These techniques (most commonly antisense therapy and RNA interference) can even have therapeutic benefit to treat a wide variety of genetic or infectious diseases as evidenced by the several RNA knockdown reagents currently in clinical trials. This protocol describes the use of validated gapmer antisense oligonucleotides (ASOs) to knockdown human MALAT1, a nuclear-retained lncRNA that is upregulated in multiple cancer cells. Methods used include cationic lipid transfection into HeLa cells, RNA isolation, and RT-qPCR analysis of the RNA knockdown levels.

Chitosan grafted/cross-linked with biodegradable polymers: A review

Public perception of polymers has been drastically changed with the improved plastic management at the end of their life. However, it is widely recognised the need of developing biodegradable polymers, as an alternative to traditional petrochemical polymers. Chitosan (CH), a biodegradable biopolymer with excellent physiological and structural properties, together with its immunostimulatory and antibacterial activity, is a good candidate to replace other polymers, mainly in biomedical applications. However, CH has also several drawbacks, which can be solved by chemical modifications to improve some of its characteristics such as solubility, biological activity, and mechanical properties. Many chemical modifications have been studied in the last decade to improve the properties of CH. This review focussed on a critical analysis of the state of the art of chemical modifications by cross-linking and graft polymerization, between CH or CH derivatives and other biodegradable polymers (polysaccharides or proteins, obtained from microorganisms, synthetized from biomonomers, or from petrochemical products). Both techniques offer the option of including a wide variety of functional groups into the CH chain. Thus, enhanced and new properties can be obtained in accordance with the requirements for different applications, such as the release of drugs, the improvement of antimicrobial properties of fabrics, the removal of dyes, or as scaffolds to develop bone tissues.

Antiviral peptides against Enterovirus A71 causing hand, foot and mouth disease

The emergence of new and resistant viruses is a serious global burden. Conventional antiviral therapy with small molecules has led to the development of resistant mutants. In the case of hand, foot and mouth disease (HFMD), the absence of a US-FDA approved vaccine calls for urgent need to develop an antiviral that could serve as a safe, potent and robust therapy against the neurovirulent Enterovirus A71 (EV-A71). Natural peptides such as lactoferrin, melittin and synthetic peptides such as SP40, RGDS and LVLQTM have been studied against EV-A71 and have shown promising results as potent antivirals in pre-clinical studies. Peptides are considered safe, efficacious and pose fewer chances of resistance. Poor pharmacokinetic features of peptides can be overcome by the use of chemical modifications to improve in vivo delivery particularly by oral route. The use of nanotechnology can remarkably assist in the oral delivery of peptides and enhance stability in vivo. This can greatly increase patient compliance and make it more attractive as antiviral therapy.

Recent advances in chemical modifications of guide RNA, mRNA and donor template for CRISPR-mediated genome editing

The discovery and applications of clustered regularly interspaced short palindromic repeat (CRISPR) systems have revolutionized our ability to track and manipulate specific nucleic acid sequences in many cell types of various organisms. The robustness and simplicity of these platforms have rapidly extended their applications from basic research to the development of therapeutics. However, many hurdles remain on the path to translation of the CRISPR systems to therapeutic applications: efficient delivery, detectable off-target effects, potential immunogenicity, and others. Chemical modifications provide a variety of protection options for guide RNA, Cas9 mRNA and donor templates. For example, chemically modified gRNA demonstrated enhanced on-target editing efficiency, minimized immune response and decreased off-target genome editing. In this review, we summarize the use of chemically modified nucleotides for CRISPR-mediated genome editing and emphasize open questions that remain to be addressed in clinical applications.

Chemical modifications and their effects on gluten protein: An extensive review

Gluten protein as one of the plant resources is susceptible to genetic, physical, chemical, enzymatic and engineering modifications. Chemical modifications have myriad advantages over other treatments, including short reaction times, low cost, no requirement for specialized equipment, and highly clear modification effects. Therefore, chemical modification of gluten can be mainly conducted via acylation, glycosylation, phosphorylation, and deamidation. The present review investigated the impact of different chemical compounds on conformations of gluten and its subunits. Moreover, their effects on the physico-chemical, morphological, and rheological properties of gluten and their subunits were studied. This allows for the use of gluten for a variety of purposes in the food and non-food industry.

RNA and CRISPR Interferences: Past, Present, and Future Perspectives

RNA interference (RNAi), a natural gene silencing process, is a widely used technique in basic research, preclinical studies, and drug development strategies. Although the technique has great potential to generate new human therapies and treat undruggable diseases, the clinical application of RNAi is still challenging primarily because of the delivery problem and potential off-target effects. Over the past two decades, great efforts have been undertaken to develop delivery agents and chemical modifications to overcome these challenges. Such advances in RNA delivery and chemical modifications have benefited researchers who are developing gene-editing therapies based on CRISPR-Cas9, an RNA-guided endonuclease, which is already having a major impact on biology and medicine. Here, I review the discovery of these two interference tools, identify the technical challenges yet to be overcome and provide some perspectives on how these two RNA-based technologies can be harnessed to treat human diseases.

RNA-based therapeutics for colorectal cancer: Updates and future directions

Colorectal cancer (CRC) is one of the most common causes of cancer death worldwide. While standard chemotherapy and new targeted therapy have been improved recently, problems such as multidrug resistance (MDR) and severe side effects remain unresolved. RNAs are essential to all biological processes including cell proliferation and differentiation, cell cycle, apoptosis, activation of tumor suppressor genes, suppression of oncogenes. Therefore, there are various potential approaches to address genetic disease like CRC at the RNA level. In contrast to conventional treatments, RNA-based therapeutics such as RNA interference, antisense oligonucleotides, RNA aptamer, ribozymes, have the advantages of high specificity, high potency and low toxicity. It has gained more and more attention due to the flexibility in modulating a wide range of targets. Here, we highlight recent advances and clinical studies involving RNA-based therapeutics and CRC. We also discuss their advantages and limitations that remain to be overcome for the treatment of human CRC.

Fluorometric determination of cardiac myoglobin based on energy transfer from a pyrene-labeled aptamer to graphene oxide

The authors describe a fluorometric assay for cardiac myoglobin (Mb), a marker for myocardial infarction. An Mb-binding aptamer was labeled with pyrene and adsorbed on the surface of graphene oxide (GO) via noncovalent and reversible binding forces. This causes the fluorescence of pyrene (best measured at excitation/emission wavelengths of 275/376 nm) to be quenched. However, fluorescence is restored on addition of pyrene due to the strong affinity between Mb and aptamer which causes its separation from GO. Fluorescence increases linearly in the 5.6-450 pM Mb concentration range, and the lower detection limit is 3.9 pM (S/N = 3). The assay was applied to the determination of cardiac Mb in spiked serum, and satisfactory results were obtained. Graphical abstract Schematic presentation of the detection of Mb (cardiac myoglobin) by using a fluorometric method based on pyrene-modified anti-Mb aptamer and GO (graphene oxide) through fluorescence quenching and subsequent recovery.

Comparison of different chemically modified inhibitors of miR-199b in vivo

MicroRNAs (miRNAs) have recently received great attention for their regulatory roles in diverse cellular processes and for their contribution to several human pathologies. Modulation of miRNAs in vivo provides beneficial therapeutic strategies for the treatment of many diseases, as evidenced by various preclinical studies. However, specific issues regarding the in vivo use of miRNA inhibitors (antimiRs) such as organ-specific delivery, optimal dosing and formulation of the best chemistry to obtain efficient miRNA inhibition remain to be addressed. Here, we aimed at comparing the in vivo efficacy of different chemistry-based antimiR oligonucleotides to inhibit cardiac expression of miR-199b, a highly promising therapeutic target for the treatment of pressure overload-induced cardiac dysfunction. For this purpose, four different designs of oligonucleotides to inhibit miR-199b were initially developed. Systemic administration to wildtype mice on three consecutive days was followed by organ harvesting, seven days after the first injection, in order to quantify the dose-dependent changes in miR-199b expression levels. When comparing the efficiency of each inhibitor at the highest applied dose we observed that the antagomir was the only inhibitor inducing complete inhibition of miR-199b in the heart. LNA reduced expression in the heart by 50 percent while the Zen-AMO and F/MOE chemistries failed to repress miR-199b expression in the heart at any given dose, in vivo. Further optimization was achieved by subjecting the antagomir and LNA nucleotides to additional chemical modifications. Interestingly, antagomir modification by replacing the cholesterol moiety from the 3' to the 5' end of the molecule significantly improved the inhibitory capacity, as reflected by a 75 percent downregulation of miR-199b expression already at a concentration of 5 mg/kg/day. Similar results could be obtained with a LNA-RNA molecule but upon administration of 80 mg/kg/day. These findings show that, from all the chemistries tested by us, an antagomir carrying the cholesterol group at the 5' end was the most efficient inhibitor of miR-199b in the heart, in vivo. Moreover, our data also emphasize the importance of chemistry optimization and best dose range finding to achieve the greatest efficacy in miRNA inhibition in vivo.

Profiling modifications for glioblastoma proteome using ultra-tolerant database search: Are the peptide mass shifts biologically relevant or chemically induced?

Peptide mass shifts were profiled using ultra-tolerant database search strategy for shotgun proteomics data sets of human glioblastoma cell lines demonstrating strong response to the type I interferon (IFNα-2b) treatment. The main objective of this profiling was revealing the cell response to IFN treatment at the level of protein modifications. To achieve this objective, statistically significant changes in peptide mass shift profiles between IFN treated and untreated glioblastoma samples were analyzed. Detailed analysis of MS/MS spectra allowed further interpretation of the observed mass shifts and differentiation between post-translational and artifact modifications. SIGNIFICANCE: Malignant cells typically acquire increased sensitivity to viruses due to the deregulated antiviral mechanisms. Therefore, a viral therapy is considered as one of the promising approaches to treat cancer. However, recent studies have demonstrated that malignant cells can preserve intact antiviral mechanisms, e.g. interferon signaling, and develop resistance to virus infection in response to interferon treatment. Post translational modifications, e.g. tyrosine phosphorylation, are the interferon signaling drivers. Thus, comprehensive characterization of modifications is crucially important, yet, most challenging problem in cancer proteomics. Here, we report on the application of the recently introduced ultra-tolerant search strategy for profiling peptide modifications in the human glioblastoma cell lines demonstrating strong response to the type I interferon (IFNα-2b) treatment. The specific aim of the study was identification of statistically significant changes in peptide mass shift profiles between IFN treated and untreated glioblastoma samples, as well as determination of whether these shifts represent the biologically relevant modification.

Non-nucleotide Modification of Anti-miRNA Oligonucleotides

MicroRNAs (miRNAs) are important modulators of gene expression. Synthetic anti-microRNA oligonucleotides (AMOs, or anti-miRs) are a form of steric-blocking antisense oligonucleotides (ASOs) that inhibit miRNA function through high-affinity binding and subsequent inactivation and/or degradation of the targeted miRNA. AMOs are a primary tool used to empirically determine the biological targets of a miRNA and can also be used therapeutically when overexpression of a miRNA contributes to a disease state. Chemical modification of synthetic AMOs enhance potency by protecting the oligonucleotide from nuclease degradation and by increasing binding affinity to the target miRNA. A new steric-blocking ASO modification strategy with favorable properties for use in AMOs was recently developed that combines use of high-affinity 2'-O-methyl RNA with terminally positioned non-nucleotide "ZEN" modifiers. This protocol describes use of ZEN AMOs in a dual-luciferase reporter assay as a simplified means to validate AMO performance or to quickly test putative miRNA binding sites in target sequences. This protocol also describes a method using Western blot analysis for quantifying the level of upregulation of proteins made from an mRNA that is thought to be under miRNA regulation, following inhibition of that miRNA by ZEN AMO treatment.

Modified siRNA effectively silence inducible immunoproteasome subunits in NSO cells

The pathogenesis of autoimmune and neurodegenerative diseases involves overexpression of inducible subunits of the immunoproteasome. However, the clinical application of inhibitors to inducible subunits of the immunoproteasome has been limited due to systemic toxicity. Here, we designed siRNAs that efficiently silence LMP2, LMP7 and MECL-1 gene expression. Inducible subunits of the immunoproteasome are complex siRNA targets because they have a long half-life; therefore, we introduced 2'-O-methyl modifications into nuclease-sensitive sites. This led to 90-95% silencing efficiency and prolonged silencing, eliminating the need for multiple transfections. Furthermore, we showed that in the absence of transfection reagent, siRNAs with lipophilic residues were able to penetrate cells more effectively and decrease the expression of inducible immunoproteasome subunits by 35% after 5 days. These results show that siRNA targeted to inducible immunoproteasome subunits have great potential for the development of novel therapeutics for autoimmune and neurodegenerative diseases.

Effect of chemical modifications on thermal, rheological and morphological properties of yellow sorghum starch

Starch isolated from yellow sorghum grains was subjected to chemical modifications like acetylation, hydroxypropylation and benzylation. Proximate compositions of these, such as crude protein, crude fat, moisture content and ash content were determined. The effects of modifications on thermal, rheological and morphological properties of yellow sorghum starch were investigated. Differential Scanning Calorimetry studies showed that the gelatinization temperature and enthalpy of modified yellow sorghum starches decreased when compared to that of native starch. The results showed that peak, hot pasting, final, breakdown and setback viscosities were significantly reduced except in hydroxypropylated starch that showed increase in breakdown and setback viscosities. Scanning electron microscopy pictures showed that the modified starch granules had disrupted surfaces compared to native starch granules; hydroxypropylated starch showed the presence of slight fragmentation and a distinct groove in their central core region. The extent of granule disruption was observed to be higher for hydroxypropylated starch than other modified starches.

miRNAs in pancreatic cancer: therapeutic potential, delivery challenges and strategies

Pancreatic ductal adenocarcinoma (PDAC) is a severe pancreatic malignancy and is predicted to victimize 1.5% of men and women during their lifetime (Cancer statistics: SEER stat fact sheet, National Cancer Institute, 2014). miRNAs have emerged as a promising prognostic, diagnostic and therapeutic tool to fight against pancreatic cancer. miRNAs could modulate gene expression by imperfect base-pairing with target mRNA and hence provide means to fine-tune multiple genes simultaneously and alter various signaling pathways associated with the disease. This exceptional miRNA feature has provided a paradigm shift from the conventional one drug one target concept to one drug multiple target theory. However, in vivo miRNA delivery is not fully realized due to challenges posed by this special class of therapeutic molecules, which involves thorough understanding of the biogenesis and physicochemical properties of miRNA and delivery carriers along with the pathophysiology of the PDAC. This review highlights the delivery strategies of miRNA modulators (mimic/inhibitor) in cancer with special emphasis on PDAC since successful delivery of miRNA in vivo constitutes the major challenge in clinical translation of this promising class of therapeutics.

Comparative serum albumin interactions and antitumor effects of Au(III) and Ga(III) ions

In the present study, interactions of Au(III) and Ga(III) ions on human serum albumin (HSA) were studied comparatively via spectroscopic and thermal analysis methods: UV-vis absorbance spectroscopy, fluorescence spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and isothermal titration calorimetry (ITC). The potential antitumor effects of these ions were studied on MCF-7 cells via Alamar blue assay. It was found that both Au(III) and Ga(III) ions can interact with HSA, however; Au(III) ions interact with HSA more favorably and with a higher affinity. FT-IR second derivative analysis results demonstrated that, high concentrations of both metal ions led to a considerable decrease in the α-helix content of HSA; while Au(III) led to around 5% of decrease in the α-helix content at 200μM, it was around 1% for Ga(III) at the same concentration. Calorimetric analysis gave the binding kinetics of metal-HSA interactions; while the binding affinity (Ka) of Au(III)-HSA binding was around 3.87×10(5)M(-1), it was around 9.68×10(3)M(-1) for Ga(III)-HSA binding. Spectroscopy studies overall suggest that both metal ions have significant effects on the chemical structure of HSA, including the secondary structure alterations. Antitumor activity studies on MCF7 tumor cell line with both metal ions revealed that, Au(III) ions have a higher antiproliferative activity compared to Ga(III) ions.

Differential scanning calorimetry to investigate G-quadruplexes structural stability

Differential Scanning Calorimetry (DSC) is a straightforward methodology to characterize the energetics of thermally-induced transitions of DNA and other biological macromolecules. Therefore, DSC has been used to study the thermodynamic stability of several nucleic acids structures. G-quadruplexes are among the most important non-canonical nucleic acid architectures that are receiving great consideration. This article reports examples on the contribution of DSC to the knowledge of G-quadruplex structures. The selected case studies show the potential of this method in investigating the structure stability of G-quadruplex forming nucleic acids, and in providing information on their structural complexity. Indeed, DSC can determine thermodynamic parameters of G-quadruplex folding/unfolding processes, but it can also be useful to reveal the formation of multiple conformations or the presence of intermediate states along the unfolding pathway, and to evaluate the impact of chemical modifications on their structural stability. This article aims to show that DSC is an important complementary methodology to structural techniques, such as NMR and X-ray crystallography, in the study of G-quadruplex forming nucleic acids.