Cyclodextrin, a novel therapeutic tool for suppressing amyloidogenic transthyretin misfolding in transthyretin-related amyloidosis

Nanoparticles of folic acid-methyl-β-cyclodextrin (FA-MβCD)/adamantane-albumin exhibit enhanced antitumor activity compared with FA-MβCD alone

Supramolecular drug carriers are a promising approach for delivering anticancer drugs with high blood retention after administration. We previously synthesized folic acid-modified methyl-β-cyclodextrin (FA-MβCD) as an anticancer drug. FA-MβCD has a selective autophagy-mediated antitumor effect on folic acid receptor (FR)-expressing cancer cells. Here, we enhanced the antitumor effect and safety of FA-MβCD by preparing a supramolecular nanoparticle formulation of FA-MβCD via host-guest interactions using an adamantane conjugate with human serum albumin (Ad-HSA). The Ad-HSA/FA-MβCD supramolecular complex prolonged the blood retention of FA-MβCD and improved its antitumor effect and safety after intravenous administration in tumor-bearing mice xenografted with FR-expressing cancer cells. These results suggest that the supramolecular technique using Ad-HSA is a promising approach for the delivery of CD-based anticancer drugs.

Cyclodextrins-Peptides/Proteins Conjugates: Synthesis, Properties and Applications

Cyclodextrins (CDs) are a family of macrocyclic oligosaccharides mostly composed of six, seven, or eight α-D-glucopyranose units with α-1,4-glycosidic bonds to form toroidal structures. The CDs possess a hydrophilic exterior and hydrophobic interior with the ability to form an inclusion complex, especially with hydrophobic molecules. However, most existing studies are about conjugation CDs with peptide/protein focusing on the formation of new systems. The CD-peptide/protein can possess new abilities; particularly, the cavity can be applied in modulation properties of more complexed proteins. Most studies are focused on drug delivery, such as targeted delivery in cell-penetrating peptides or co-delivery. The co-delivery is based mostly on polylysine systems; on the other hand, the CD-peptide allows us to understand biomolecular mechanisms such as fibryllation or stem cell behaviour. Moreover, the CD-proteins are more complexed systems with a focus on targeted therapy; these conjugates might be controllable with various properties due to changes in their stability. Finally, the studies of CD-peptide/protein are promising in biomedical application and provide new possibilities for the conjugation of simple molecules to biomolecules.

Twenty Years of Research on Cyclodextrin Conjugates with PAMAM Dendrimers

Recently, the number of gene and oligonucleotide drugs are increasing. Of various drug delivery systems (DDSs) for gene and oligonucleotide drugs, few examples of the clinical application of polymer as drug carriers are known, despite development of the novel polymers has been progressing. Cyclodextrin (CD) conjugates with starburst polyamidoamine (PAMAM) dendrimer (CDEs), as a new type of polymer-based carriers, were first published in 2001. After that, galactose-, lactose-, mannose-, fucose-, folate-, and polyethyleneglycol (PEG)-appended CDEs have been prepared for passive and active targeting for gene, oligonucleotide, and low-molecular-weight drugs. PEG-appended CDE formed polypsuedorotaxanes with α-CD and γ-CD, which are useful for a sustained release system of gene and oligonucleotide drugs. Interestingly, CDEs were found to have anti-inflammatory effects and anti-amyloid effects themselves, which have potential as active pharmaceutical ingredients. Most recently, CDE is reported to be a useful Cas9-RNA ribonucleoproteins (Cas9 RNP) carrier that induces genome editing in the neuron and brain. In this review, the history and progression of CDEs are overviewed.

[Supramolecular Pharmaceutical Sciences: A Novel Concept for Future Pharmaceutical Sciences]

Supramolecular chemistry is a useful and important domain for understanding pharmaceutical sciences, since various physiological reactions (e.g., protein association) and drug activities (e.g., the substrate/receptor reaction) are based on supramolecular chemistry. Biological components, such as DNA and cells, are also supermolecules. However, supramolecular chemistry to date has not been a major domain in the field of pharmaceutical study. In this article, we propose a new concept in pharmaceutical sciences termed "supramolecular pharmaceutical sciences" which combines pharmaceutical sciences and supramolecular chemistry. "Supramolecular pharmaceutical sciences" could encompass strictly controlled molecular arrangement, stimulus responsible molecular motion, new functions beyond those of existing molecules, more accurate drug design, new active pharmaceutical ingredients, new perspectives for the investigation of the drug mechanisms, and novel pharmaceutical technologies. Moreover, pharmaceutical sciences are useful for supramolecular chemistry, because biological reactions are very accurate reactions, making this a win-win relationship. Thus, supramolecular pharmaceutical sciences could be useful for developing new methods, hypotheses, ideas, materials, mechanisms, and strategies in the realm of pharmaceutical science.

Cyclodextrin enhanced the soluble expression of Bacillus clarkii γ-CGTase in Escherichia coli

BACKGROUND

Cyclodextrin glycosyltransferases (CGTases) catalyze the synthesis of cyclodextrins, which are circular α-(1,4)-linked glucans used in many applications in the industries related to food, pharmaceuticals, cosmetics, chemicals, and agriculture, among others. Economic use of these CGTases, particularly γ-CGTase, requires their efficient production. In this study, the effects of chemical chaperones, temperature and inducers on cell growth and the production of soluble γ-CGTase by Escherichia coli were investigated.

RESULTS

The yield of soluble γ-CGTase in shake-flask culture approximately doubled when β-cyclodextrin was added to the culture medium as a chemical chaperone. When a modified two-stage feeding strategy incorporating 7.5 mM β-cyclodextrin was used in a 3-L fermenter, a dry cell weight of 70.3 g·L^- 1 was achieved. Using this cultivation approach, the total yield of γ-CGTase activity (50.29 U·mL^- 1) was 1.71-fold greater than that observed in the absence of β-cyclodextrin (29.33 U·mL^- 1).

CONCLUSIONS

Since β-cyclodextrin is inexpensive and nontoxic to microbes, these results suggest its universal application during recombinant protein production. The higher expression of soluble γ-CGTase in a semi-synthetic medium showed the potential of the proposed process for the economical production of many enzymes on an industrial scale.

Supramolecular Pharmaceutical Sciences: A Novel Concept Combining Pharmaceutical Sciences and Supramolecular Chemistry with a Focus on Cyclodextrin-Based Supermolecules

Supramolecular chemistry is an extremely useful and important domain for understanding pharmaceutical sciences because various physiological reactions and drug activities are based on supramolecular chemistry. However, it is not a major domain in the pharmaceutical field. In this review, we propose a new concept in pharmaceutical sciences termed "supramolecular pharmaceutical sciences," which combines pharmaceutical sciences and supramolecular chemistry. This concept could be useful for developing new ideas, methods, hypotheses, strategies, materials, and mechanisms in pharmaceutical sciences. Herein, we focus on cyclodextrin (CyD)-based supermolecules, because CyDs have been used not only as pharmaceutical excipients or active pharmaceutical ingredients but also as components of supermolecules.

Dual targeting system by supramolecular complex of folate-conjugated methyl-β-cyclodextrin with adamantane-grafted hyaluronic acid for the treatment of colorectal cancer

In our previous study, we demonstrated that folate-appended methyl‑β‑cyclodextrin (FA-M-β-CyD) was a promising antitumor agent for the treatment of folate receptor-α (FR-α)-expressing tumors. In the present study, to enhance the antitumor effect of FA-M-β-CyD against FR-α- and CD44-expressing colorectal cancer cells, we synthesized a dual targeting supramolecular complex composed of FA-M-β-CyD and adamantane-grafted hyaluronic acid (Ad-HA). The supramolecular complex of Ad-HA/FA-M-β-CyD showed higher cytotoxic activity in HCT116 cells (FR-α (+), CD44 (+)), a human colon cancer cell line, than FA-M-β-CyD alone. In addition, the cytotoxic activity of Ad-HA/FA-M-β-CyD was significantly impaired by the addition of FA and HA, as inhibitors of FR-α and CD44, respectively. Furthermore, tetramethylrhodamine isothiocyanate (TRITC)-labeled FA-M-β-CyD was efficiently internalized into HCT116 cells through supramolecular complexation with Ad-HA, compared to that of TRITC-FA-M-β-CyD alone. Additionally, Ad-HA/FA-M-β-CyD induced mitophagy in HCT116 cells. These results suggest that Ad-HA/FA-M-β-CyD targeted HCT116 cells, as well as induced mitophagy-mediated cell death. Notably, an intravenous injection of the Ad-HA/FA-M-β-CyD complex in a mouse model of colorectal cancer significantly ameliorated the growth of tumor polyps. Collectively, these results suggest that Ad-HA/FA-M-β-CyD has antiproliferation effects in tumors, based on the dual targeting activity.

Supramolecular Complex of Methyl-β-cyclodextrin with Adamantane-Grafted Hyaluronic Acid as a Novel Antitumor Agent

Methyl-β-cyclodextrin (M-β-CyD) exhibits cytotoxic activity, and has the potentials as an antitumor agent. However, a tumor-selectivity of M-β-CyD is low, leading to low antitumor activity and the adverse effects. Meanwhile, hyaluronic acid (HA) is known as a promising tumor targeting ligand, because various cancer cells overexpress CD44, a HA-binding glycoprotein. In the present study, to develop a tumor-selective delivery system for M-β-CyD, we designed a supramolecular complex of M-β-CyD with adamantane-grafted HA (Ad-HA/M-β-CyD) and evaluated it as a tumor-selective antitumor agent. M-β-CyD formed a stable complex with Ad-HA (K_c>10⁴ M^-1). In addition, Ad-HA/M-β-CyD formed slightly a negative-charged nanoparticle with ca. 140 nm of a particle size, indicating the favorable physicochemical properties for antitumor agents. Ad-HA/M-β-CyD showed the superior cytotoxic activity via CD44-mediated endosomal pathways in HCT116 cells (CD44(+)), a human colon cancer cell line. In addition, cytotoxic activity of Ad-HA/M-β-CyD was induced by apoptosis. These results suggest that Ad-HA/M-β-CyD has the potentials as a tumor-selective supramolecular antitumor agent.

Cyclodextrins as Protective Agents of Protein Aggregation: An Overview

Cyclodextrins are extensively used in different fields (e.g., catalysis, chromatography, pharma, supramolecular chemistry, bioorganic chemistry, and bioinorganic chemistry), and their applications have been widely reviewed. Their main application in the field of pharmaceutical is as a drug carrier. This review overviews, for the first time, the use of cyclodextrins and their derivatives as antiaggregant agents in a number of proteins (e.g., amyloid-β, insulin, recombinant human growth hormone, prion protein, transthyretin, and α-synuclein) and some multimeric enzymes. There are many diseases that are correlated to protein misfolding and amyloid formation processes affecting numerous organs and tissues. There are over 30 different amyloid proteins and a number of corresponding diseases. Alzheimer's disease is the most common neurodegenerative disease. Treatment of these diseases is still a goal to reach, and many molecules are studied in this perspective. Cyclodextrins have also been studied, and they show great potential; as such, further studies could be very promising. This review aims to be a stimulus for the design of new cyclodextrin derivatives to obtain multifunctional systems with antiaggregant activity.

Inhibition of insulin amyloid fibril formation by cyclodextrins

Localized insulin-derived amyloid masses occasionally form at the site of repeated insulin injections in patients with insulin-dependent diabetes and cause subcutaneous insulin resistance. Various kinds of insulin including porcine insulin, human insulin, and insulin analogues reportedly formed amyloid fibrils in vitro and in vivo, but the impact of the amino acid replacement in insulin molecules on amyloidogenicity is largely unknown. In the present study, we demonstrated the difference in amyloid fibril formation kinetics of human insulin and insulin analogues, which suggests an important role of the C-terminal domain of the insulin B chain in nuclear formation of amyloid fibrils. Furthermore, we determined that cyclodextrins, which are widely used as drug carriers in the pharmaceutical field, had an inhibitory effect on the nuclear formation of insulin amyloid fibrils. These findings have significant implications for the mechanism underlying insulin amyloid fibril formation and for developing optimal additives to prevent this subcutaneous adverse effect.

Recent advances in transthyretin amyloidosis therapy

Mutant (MT) forms of transthyretin (TTR) cause the most common type of autosomal-dominant hereditary systemic amyloidosis-familial amyloidotic polyneuropathy (FAP). Until 20 years ago, FAP was thought to be an endemic disease, but FAP is known to occur worldwide. To date, more than 130 mutations in the TTR gene have been reported. Genotype-phenotype correlations are seen in FAP, and some variation in clinical presentation is often observed in individual kindreds with the same mutation and even among family members. Of the pathogenic TTR mutations, Val30Met was the first to be identified and is the most frequent known mutation found throughout the world. Studies of patients with FAP amyloidogenic TTR (ATTR) Val30Met documented sensorimotor polyneuropathy, autonomic dysfunction, heart and kidney failure, gastrointestinal tract (GI) disorders, and other symptoms leading to death, usually within 10 years of the onset of disease. Diagnosis is sometimes delayed, especially in patients without a clear family history and typical clinical manifestations, since diagnosis requires various studies and techniques such as histopathology, genetic testing, and mass spectrometry. For treatment of FAP, liver transplantation (LT) reportedly halts the progression of clinical manifestations. Exchange of an FAP patient's diseased liver with a healthy liver causes MT TTR in the body to be replaced by wild-type (WT) TTR. Although clinical evaluations indicated that progression of other clinical symptoms such as peripheral neuropathy, GI symptoms, and renal involvement usually halted after LT in FAP ATTR Val30Met patients, recent studies suggested that LT failed to prevent progression of cardiac amyloidosis in FAP ATTR Val30Met patients after LT, with this failure reportedly being due to continued formation of amyloid that derived mainly from WT TTR secreted from the transplanted non-mutant liver graft. In recent years, many therapeutic strategies have been proposed, and several ongoing therapeutic trials involve, for example, stabilizers of TTR tetramers (tafamidis and diflunisal) and gene therapies to suppress TTR expression (antisense methods and use of small interfering RNAs). These novel therapies may prove to prevent progression of FAP.

Potential use of glucuronylglucosyl-β-cyclodextrin as a novel therapeutic tool for familial amyloidotic polyneuropathy

Transthyretin (TTR)-related familial amyloidotic polyneuropathy, which is induced by amyloidogenic transthyretin (ATTR), is characterized by systemic accumulation of amyloid fibrils. Although it is believed that protein misfolding of monomeric form of TTR is a rate-limiting step for TTR amyloid formation, no effective therapy targeting this misfolding step is available. Our recent studies revealed that cyclodextrins (CyDs), cyclic oligosaccharides composed of glucose units, might interact with TTR and prevent the protein misfolding. In this study, we focused on and elucidated the inhibitory effect of 6-O-α-(4-O-α-D-Glucuronyl)-D-glucosyl-β-CyD (GUG-β-CyD) on TTR amyloid formation. Tryptophan (Trp) fluorescence and (1)H-NMR spectroscopy analyses indicated that GUG-β-CyD stabilized TTR conformation via interaction with the hydrophobic amino acids of TTR. Moreover, GUG-β-CyD suppressed TTR deposition in transgenic rats possessing a human ATTR V30M gene in vivo. Collectively, these data indicate that GUG-β-CyD may inhibit TTR misfolding by stabilizing its conformation, which, in turn, suppresses TTR amyloid formation.

Transthyretin amyloidosis and the kidney

The amyloidoses are protein-misfolding disorders associated with progressive organ dysfunction. Immunoglobulin light chain is the most common, amyloid A the longest recognized, and transthyretin-associated amyloidosis (ATTR) the most frequent inherited systemic form. Although ATTR, an autosomal-dominant disease, is associated with at least 100 different transthyretin (TTR) mutations, the single amino-acid substitution of methionine for valine at position 30 is the most common mutation. Each variant has a different organ involvement, although clinical differences attributed to environmental and genetic factors exist within the same mutation. Peripheral neuropathy and cardiomyopathy are broadly described, and insights into disease reveal that kidney impairment and proteinuria are also clinical features. This review combines clinical and laboratory findings of renal involvement from the main geographic regions of disease occurrence and for different mutations of TTR. Fifteen nephropathic variants have been described, but the TTR V30M mutation is the best documented. Nephropathy affects patients with late-onset neuropathy, low penetrance in the family, and cardiac dysrhythmias. Microalbuminuria can be the disorder's first presentation, even before the onset of neuropathy. Amyloid renal deposits commonly occur, even in the absence of urinary abnormalities. The experience with renal replacement therapy is based on hemodialysis, which is associated with poor survival. Because TTR is synthesized mainly in the liver, liver transplantation has been considered an acceptable treatment; simultaneous liver-kidney transplantation is recommended to avoid recurrence of nephropathy. In addition, the kidney-safety profile of new drugs in development may soon be available.

Familial amyloidotic polyneuropathy and transthyretin

There has been much progress in our understanding of transthyretin (TTR)-related amyloidosis including familial amyloidotic polyneuropathy (FAP), senile systemic amyloidosis and its related disorders from many clinical and experimental aspects. FAP is an inherited severe systemic amyloidosis caused by mutated TTR, and characterized by amyloid deposition mainly in the peripheral nervous system and the heart. Liver transplantation is the only available treatment for the disease. FAP is now recognized not to be a rare disease, and to have many variations based on genetical and biochemical variations of TTR. This chapter covers the recent advances in the clinical and pathological aspects of, and therapeutic approaches to FAP, and the trend as to the molecular pathogenesis of TTR.