Glucocorticoid-loaded pH/ROS dual-responsive nanoparticles alleviate joint destruction by downregulating the NF-κB signaling pathway.

Rheumatoid arthritis (RA) is an autoimmune disease causing severe symptoms that are difficult to treat. Nano-drug delivery system is recognized as a promising strategy for management of RA. However, how to thoroughly release payloads from nanoformulations and synergistic therapy of RA needs to be further investigated. To address this issue, a pH and reactive oxygen species (ROS) dual-responsive, methylprednisolone (MPS)-loaded and arginine-glycine-aspartic acid (RGD)-modified nanoparticles (NPs) was fabricated using phytochemical and ROS-responsive moiety co-modified α-cyclodextrin (α-CD) as a carrier. In vitro and in vivo experiments verified that the pH/ROS dual-responsive nanomedicine could be efficiently internalized by activated macrophages and synovial cells, and the released MPS could promote transformation of M1-type macrophages into M2 phenotype, thereby down-regulating pro-inflammatory cytokines. In vivo experiments demonstrated that the pH/ROS dual-responsive nanomedicine was remarkably accumulated in the inflamed joints of mice with collagen-induced arthritis (CIA). The accumulated nanomedicine could obviously relieve joint swelling and cartilage destruction without obvious adverse effects. Importantly, the expression of interleukin-6 and tumor necrosis factor-α in the joints of CIA mice were significantly inhibited by the pH/ROS dual-responsive nanomedicine in comparison with free drug and non-targeted counterparts. In addition, the expression of the NF-κB signaling pathway molecule P65 was also significantly decreased by nanomedicine-treatment. Our results reveal that MPS-loaded pH/ROS dual-responsive NPs can effectively alleviate joint destruction via down-regulation of the NF-κB signaling pathway. STATEMENT OF SIGNIFICANCE: Nanomedicine is recognized as an attractive method for the targeting treatment of rheumatoid arthritis (RA). To thorough release of payloads from nanoformulations and synergistic therapy of RA, herein, a phytochemical and ROS-responsive moiety co-modified α-cyclodextrin was used as a pH/ROS dual-responsive carrier to encapsulate methylprednisolone to manage RA. The fabricated nanomedicine can effectively release its payloads under pH and/or ROS microenvironment, and the released drugs dramatically promote transformation of M1-type macrophages into M2 phenotype to reduce the release of pro-inflammatory cytokines. The prepared nanomedicine also obviously decreased the NF-κB signaling pathway molecule P65 expression in the joints, thereby down-regulating pro-inflammatory cytokines expression to alleviate joint swelling and cartilage destruction. We provided a candidate for the targeting treatment of RA.

A pH-responsive citric-acid/α-cyclodextrin-functionalized Fe3O4 nanoparticles as a nanocarrier for quercetin: An experimental and DFT study.

Developing new nanocarriers and understanding the interactions between the drug and host molecules in the nanocarrier at the molecular level is of importance for future of nanomedicine. In this work, we synthesized and characterized a series of iron oxide nanoparticles (IONPs) functionalized with different organic molecules (citric acid, α-cyclodextrin, and citric acid/α-cyclodextrin composite). It was found that incorporation of citric acid into the α-cyclodextrin had negligible effect on the adsorption efficiency (<5%) of citric acid/α-cyclodextrin functionalized IONPs, while the isotherm adsorption data were well described by the Langmuir isotherm model (qmax = 2.92 mg/g at T = 25 °C and pH = 7). In addition, the developed nanocarrier showed pH-responsive behavior for releasing the quercetin molecules as drug model, where the Korsmeyer-Peppas model could describe the release profile with Fickian diffusion (n < 0.45 for at all pH and temperatures). Then, Density functional theory was applied to calculate the absolute binding energies (ΔEb) of the complexation of quercetin with different host molecules in the developed nanocarriers. The calculated energies are as follow: 1) quercetin and citric acid: ΔEb = -16.58 kcal/mol, 2) quercetin and α-cyclodextrin: ΔEb = -46.98 kcal/mol, and 3) quercetin and citric acid/α-cyclodextrin composite: ΔEb = -40.15 kcal/mol. It was found that quercetin tends to interact with all hosts via formation of hydrogen bonds and van der Waals interactions. Finally, the cytotoxicity of the as-developed nanocarriers was evaluated using MTT assay and both normal NIH-3T3 and cancereous HeLa cells. The cell viability results showed that the quercetin could be delivered effectively to the HeLa cells due to the acidic environment inside the cells with minimum effect on the viability of NIH-3T3 cells. These results might open a new window to design of stimuli-responsive nanocarriers for drug delivery applications.

AIE Supramolecular Assembly with FRET Effect for Visualizing Drug Delivery.

Here, we constructed a nanostructured pH/redox dual-responsive supramolecular drug carrier with both aggregation-induced emission (AIE) and Forster resonance energy transfer (FRET) effects, which enabled selective drug release and monitoring drug delivery and release processes. Taking the hyperbranched polyamide amine (H-PAMAM) with intrinsic AIE effects as the core, poly(ethylene glycol) (PEG) was bridged on its periphery by dithiodipropionic acid. Then, through the host-guest interaction of PEG and α-cyclodextrin, the supramolecular nanoparticles with AIE effects were constructed to load the anticancer drug doxorubicin (DOX). The supramolecular assembly has sufficiently large DOX loading due to the abundant cavities formed by branched structures. The hyperbranched core H-PAMAM has strong fluorescence, and the dynamic track of drug carriers and the dynamic drug release process can be monitored by the AIE and FRET effects between H-PAMAM and DOX, respectively. Furthermore, the introduction of disulfide bonds and the pH sensitivity of H-PAMAM enable the achievement of rapid selective release of loaded DOX at the tumor while remaining stable under normal physiological conditions. In vitro cytotoxicity indicates that the drug-loaded supramolecular assembly has a good therapeutic effect on cancer. In addition, the H-PAMAM core is different from the traditional AIE functional group, which has no conjugated structure, such as a benzene ring, thereby providing better biocompatibility. This technology will have broad applications as a new drug delivery system.

Mucoadhesive S-protected thiolated cyclodextrin-iodine complexes: a promising strategy to prolong mucosal residence time of iodine.

AIM: The purpose of this study was to develop S-protected thiolated α-cyclodextrin-iodine complexes providing prolonged mucosal residence time and sustained release of the antimicrobial agent. MATERIALS & METHODS: First, L-cysteine was conjugated with 2-mercaptonicotinic acid to generate cysteine-2-mercaptonicotinic acid (Cys-MNA). Subsequently, α-CD was oxidized with NaIO4 and Cys-MNA was bound to the resulting aldehyde groups via reductive amination. Finally, iodine was incorporated into complex. RESULT: S-protected thiolated α-CD displayed 3804 µmol/g MNA groups. The inclusion constant (KC) between iodine and S-protected thiolated α-CD was 5.37 × 104 M-1. In vitro release of iodine was around 15% per hour, whereas mucoadhesive properties showed 38-fold improvement in mucoadhesion. The complex did not show cytotoxicity at a concentration of 0.5% (m/v). In addition, complexes exhibited pronounced antimicrobial activity against Staphylococcus aureus and Escherichia coli. CONCLUSION: According to these results, S-protected thiolated α-CD-iodine complex might be a promising novel formulation for the mucosal use of iodine.

A Combined Approach of NMR and Mass Spectrometry Techniques Applied to the α-Cyclodextrin/Moringin Complex for a Novel Bioactive Formulation †.

Moringin, obtained via enzymatic conversion of the glucosinolate precursor glucomoringin, is an uncommon member of the isothiocyanate class, and has been proven to possess a broad range of biological activities such as antitumor activity, protection against neurodegenerative disorders and bactericidal effects. Since moringin is weakly soluble in water and unstable in aqueous medium, cyclodextrins (CDs) were considered for the development of a new moringin formulation, with a view to improving its solubility and stability in aqueous solution for use as an anti-inflammatory. A combined structural study using proton nuclear magnetic resonance (¹H-NMR), diffusion-ordered spectroscopy (DOSY) and ion mobility mass spectrometry (IM-MS) is reported, highlighting the formation of a 1:1 α-CD/moringin inclusion complex. The association constant K was determined (1300 M-1 at 300 K). Completion of the structural characterization was performed by T-ROESY and MS/MS experiments, which evidenced the mode of penetration of moringin into α-CD. Finally, the "chaperone-like" properties of α-CD with respect to the stability of moringin have been highlighted.

Reduction-active polymeric prodrug micelles based on α-cyclodextrin polyrotaxanes for triggered drug release and enhanced cancer therapy.

As one of the medical polymers approved by US Food and Drug Administration (FDA), poly(ethylene glycol) has low toxicity, high stability, good biocompatibility, unique physical and chemical properties. Cyclodextrin is an ideal candidate as a drug carrier due to its special structures and characteristics. These two materials were successfully assembled through chemosynthesis in combination with the hydrophilic poly(ethylene glycol) methyl ether methacrylate (OEGMA) chain and hydrophobic polymeric camptothecin (CPT) chain by atom transfer radical polymerization (ATRP). The introduction of disulfide bond of monomer was aimed to realize reduction agent-triggered release of active CPT. The obtained amphipathic prodrug [(Denoted as PC-PCPT-b-POEGMA (PCCO)] could form nano-sized polymeric micelles, which could release more than 85% of the loaded CPT via triggered cleavage of the disulfide linker. The cellular co-localization study revealed the potential pathway of drug internalization. Moreover, the PCCO micelles showed good biocompatibility in vivo after intravenous injection on a mouse model. This new CPT-loaded prodrug system could be prepared with low cost, and showed efficient and controlled drug release and favorable biocompatibility, demonstrating a promising potential as a stimuli-responsive polymeric prodrug for future clinical applications.

Enhancement of iodinin solubility by encapsulation into cyclodextrin nanoparticles.

Phenazine is known to regroup planar nitrogen-containing heterocyclic compounds. It was used here to enhance the bioavailability of the biologically important compound iodinin, which is near insoluble in aqueous solutions. Its water solubility has led to the development of new formulations using diverse amphiphilic α-cyclodextrins (CDs). With the per-[6-desoxy-6-(3-perfluorohexylpropanethio)-2,3-di-O-methyl]-α-CD, we succeeded to get iodinin-loaded nanoformulations with good parameters such as a size of 97.9 nm, 62% encapsulation efficiency and efficient control release. The study presents an interesting alternative to optimizing the water solubility of iodinin by chemical modifications of iodinin.

The α-cyclodextrin complex of the Moringa isothiocyanate suppresses lipopolysaccharide-induced inflammation in RAW 264.7 macrophage cells through Akt and p38 inhibition.

In the last decades, a growing need to discover new compounds for the prevention and treatment of inflammatory diseases has led researchers to consider drugs derived from natural products as a valid option in the treatment of inflammation-associated disorders. The purpose of the present study was to investigate the anti-inflammatory effects of a new formulation of Moringa oleifera-derived 4-(α-L-rhamnopyranosyloxy)benzyl isothiocyanate as a complex with alpha-cyclodextrin (moringin + α-CD) on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells, a common model used for inflammation studies. In buffered/aqueous solution, the moringin + α-CD complex has enhanced the water solubility and stability of this isothiocyanate by forming a stable inclusion system. Our results showed that moringin + α-CD inhibits the production of inflammatory mediators in LPS-stimulated macrophages by down-regulation of pro-inflammatory cytokines (TNF-α and IL-1ß), by preventing IκB-α phosphorylation, translocation of the nuclear factor-κB (NF-κB), and also via the suppression of Akt and p38 phosphorylation. In addition, as a consequence of upstream inhibition of the inflammatory pathway following treatment with moringin + α-CD, the modulation of the oxidative stress (results focused on the expression of iNOS and nitrotyrosine) and apoptotic pathway (Bax and Bcl-2) was demonstrated. Therefore, moringin + α-CD appears to be a new relevant helpful tool to use in clinical practice for inflammation-associated disorders.

Alpha- and Beta-Cyclodextrin Inclusion Complexes with 5-Fluorouracil: Characterization and Cytotoxic Activity Evaluation.

Cyclodextrins are natural macrocyclic oligosaccharides able to form inclusion complexes with a wide variety of guests, affecting their physicochemical and pharmaceutical properties. In order to obtain an improvement of the bioavailability and solubility of 5-fluorouracil, a pyrimidine analogue used as chemotherapeutic agent in the treatment of the colon, liver, and stomac cancers, the drug was complexed with alpha- and beta-cyclodextrin. The inclusion complexes were prepared in the solid state by kneading method and characterized by Fourier transform-infrared (FT-IR) spectroscopy and X-ray powder diffractometry. In solution, the 1:1 stoichiometry for all the inclusion complexes was established by the Job plot method and the binding constants were determined at different pHs by UV-VIS titration. Furthermore, the cytotoxic activity of 5-fluorouracil and its complexation products were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on MCF-7 (breast cancer cell line), Hep G2 (hepatocyte carcinoma cell line), Caco-2 (colon adenocarcinoma cell line), and A-549 (alveolar basal epithelial carcinoma cell line). The results showed that both inclusion complexes increased the 5-fluorouracil capability of inhibiting cell growth. In particular, 5-fluorouracil complexed with beta-cyclodextrin had the highest cytotoxic activity on MCF-7; with alpha-cyclodextrin the highest cytotoxic activity was observed on A-549. The IC50 values were equal to 31 and 73 µM at 72 h, respectively. Our results underline the possibility of using these inclusion complexes in pharmaceutical formulations for improving 5-fluorouracil therapeutic efficacy.

Oil-cyclodextrin based beads for oral delivery of poorly-soluble drugs.

The main interest of cyclodextrins results from their ability to form inclusion complexes with hydrophobic molecules. This property is employed in pharmaceutical industry to facilitate the formulation of poorly-soluble and/or fragile drugs. Cyclodextrins are also used to form or stabilise dispersed systems. An original multiparticulate system named "beads" is obtained thanks to the interactions occurring between the molecules of α cyclodextrin and the triglycerides of vegetable oils. Beads are prepared by a simple process involving the external shaking of a mixture of an aqueous solution of α cyclodextrin with soybean oil. This is done without any organic solvent or surface-active agent. Once freezedried, beads have a diameter of 1.6 mm and a high lipid content. They consist in a partially crystalline matrix of cyclodextrin surrounding microdomains of oil. The coating of beads with a layer of α cyclodextrin improves their resistance in gastro- intestinal fluids and prolongs the release of drugs. Beads can also be manufactured from mineral oils with α cyclodextrin and from silicone oils with γ cyclodextrin. Poorly-soluble drugs which do not form inclusion complexes with α cyclodextrin are encapsulated in beads with high efficiency and drug loading. In rats, the oral bioavailability of isotretinoin is twofold enhanced with uncoated beads as compared to the lipid content of a soft capsule. The relative oral bioavailability of indomethacin is improved with both coated and uncoated beads versus a commercial hard capsule. Beads demonstrate an important potential for the encapsulation of poorly-soluble and/or fragile compounds and their delivery by oral route.

Cyclodextrin/Dendrimer conjugates as DNA and oligonucleotide carriers.

Recently, various cyclodextrin (CyD)-grafted polymers and supramolecules have been developed as gene and oligonucleotide carriers. We have demonstrated that among the various polyamidoamine starburst(TM) dendrimers (dendrimers) conjugates with CyDs (CDEs), the dendrimer (G2 or G3) conjugate with α-CyD showed high gene and oligonucleotide transfer activity with negligible cytotoxicity. In addition, to develop tissue- or cell-specific gene transfer carriers, we also prepared α-CDEs modified with functional molecules, such as mannose, fucose, galactose, lactose, polyethylene glycol (PEG) and folate-PEG. Moreover, polypseudorotaxane-appended α-CDEs were developed as sustained release systems for DNA and siRNA. Interestingly, glucronylglucosyl-ß-CyD conjugates with dendrimer (G2) (GUG-ß-CDE (G2)) showed high gene transfer activity compared to α-CDE (G2) and ß-CDE (G2). In this review, we focus on the potential use of various CDEs as DNA and oligonucleotide transfer carriers.

Poloxamine-cyclodextrin-simvastatin supramolecular systems promote osteoblast differentiation of mesenchymal stem cells.

Osteogenic/osteoinductive systems combine simvastatin, poloxamine Tetronic 908 (T908) and α-cyclodextrins (αCDs) in a supramolecular network that enhances the solubility/stability of the simvastatin hydroxy acid form and synergistically promotes osteoblast differentiation. Incorporation of 5% αCD transforms dilute T908 solutions (as low as 2% copolymer) into gels, enhances the osteoinductive activity of T908, and provides simvastatin sustained release for more than one week, which results in higher and more prolonged alkaline phosphatase (ALP) activity. The performance of the intrinsically osteoinductive polypseudorotaxane scaffold can be easily tuned by modifying the concentrations of T908, αCD, and simvastatin in a certain range of values. Moreover, the use of affordable, stable materials that can be sterilized applying a conventional method make the supramolecular gels advantageous candidates as scaffolds to be applied in the critical defect using minimally invasive techniques.

Intranasal administration of PACAP: uptake by brain and regional brain targeting with cyclodextrins.

Pituitary adenylate cyclase activating polypeptide (PACAP) is a potent neurotrophic and neuroprotectant that is transported across the blood-brain barrier in amounts sufficient to affect brain function. However, its short half-life in blood makes it difficult to administer peripherally. Here, we determined whether the radioactively labeled 38 amino acid form of PACAP can enter the brain after intranasal (i.n.) administration. Occipital cortex and striatum were the regions with the highest uptake, peaking at levels of about 2-4% of the injected dose per gram of brain region. Inclusion of unlabeled PACAP greatly increased retention of I-PACAP by brain probably because of inhibition of the brain-to-blood efflux transporter for PACAP located at the blood-brain barrier. Sufficient amounts of PACAP could be delivered to the brain to affect function as shown by improvement of memory in aged SAMP8 mice, a model of Alzheimer's disease. We found that each of three cyclodextrins when included in the i.n. injection produced a unique distribution pattern of I-PACAP among brain regions. As examples, ß-cyclodextrin greatly increased uptake by the occipital cortex and hypothalamus, α-cyclodextrin increased uptake by the olfactory bulb and decreased uptake by the occipital cortex and striatum, and (2-hydropropyl)-ß-cyclodextrin increased uptake by the thalamus and decreased uptake by the striatum. These results show that therapeutic amounts of PACAP can be delivered to the brain by intranasal administration and that cyclodextrins may be useful in the therapeutic targeting of peptides to specific brain regions.

Polypseudorotaxanes of pegylated α-cyclodextrin/polyamidoamine dendrimer conjugate with cyclodextrins as a sustained release system for DNA.

Nonviral gene delivery suffers from a number of limitations including short transgene expression times and low transfection efficiency. In this study, we examined whether polypseudorotaxanes (PPRXs) of polyethylene glycol (PEG, molecular weight: 2,000)-grafted α-cyclodextrin (α-CyD)/polyamidoamine dendrimer conjugate (PEG-α-CDE) with CyDs have the potential for the novel sustained release systems for plasmid DNA (pDNA). The PEG-α-CDE/pDNA complex formed PPRXs with α-CyD and γ-CyD solutions, but not with ß-CyD solution. In the PEG-α-CDE/CyDs PPRX systems, 20.6mol of α-CyD and 11.8mol of γ-CyD were involved in the PPRXs formation with one PEG chain by α-CyD and γ-CyD, respectively, consistent with in the PEG-dendrimer/CyDs systems. PEG-α-CDE/pDNA/α-CyD PPRX and PEG-α-CDE/pDNA/γ-CyD PPRX formed hexagonal and tetragonal columnar channels in the crystalline phase, respectively. In addition, the CyDs PPRX provided the sustained release of pDNA from PEG-α-CDE complex with pDNA at least 72 h in vitro. The release of pDNA from CyDs PPRX retarded as the volume of dissolution medium decreased. Furthermore, the PEG-α-CDE/γ-CyD PPRX system showed sustained transfection efficiency after intramuscular injection to mice at least for 14days. These results suggest that the PEG-α-CDE/CyD PPRX systems are useful for novel sustained DNA release systems.

Enhancement of stability and skin permeation by sucrose stearate and cyclodextrins in progesterone nanoemulsions.

Lecithin-based nanoemulsions are colloidal drug delivery systems which offer fundamental advantages in topical therapy, such as excellent skin permeation of lipophilic drugs; however, their physicochemical long-term stability is usually rather poor without the use of additional synthetic surfactants such as polysorbates. In a novel approach negatively and positively charged formulations were developed without the use of conventional synthetic surfactants. Natural substances such as sucrose esters and different cyclodextrins were additionally used as stabilising agents. Emphasis was laid on optimisation of the homogenisation process and formulation properties. The optimised formulations were tested for their potential as drug delivery systems for progesterone. Furthermore, crucial formulation parameters such as particle size and zeta potential were monitored for more than a year. In this context, the effect of the natural excipients sucrose stearate and cyclodextrins alpha, beta and gamma on in vitro skin permeation was investigated; the influence of the positive particle surface charge induced by incorporation of the cationic phytosphingosine was evaluated as well. The results showed that in particular the cyclodextrins seemed to induce fundamental changes in formulation microstructure as confirmed by cryo TEM, thus leading to remarkably increased skin permeation rates of progesterone compared to the control.

Involvement of PI3K-Akt-Bad pathway in apoptosis induced by 2,6-di-O-methyl-beta-cyclodextrin, not 2,6-di-O-methyl-alpha-cyclodextrin, through cholesterol depletion from lipid rafts on plasma membranes in cells.

Cyclodextrins (CyDs), which are widely used to increase the solubility of drug in pharmaceutical fields, are known to induce hemolysis and cytotoxicity at high concentrations. However, it is still not unclear whether cell death induced by CyDs is apoptosis or not. Therefore, in the present study, we investigated the effects of various kinds of CyDs on apoptosis in the cells such as NR8383 cells, A549 cells and Jurkat cells. Of various CyDs, methylated CyDs inducted cell death under the present experimental conditions, but hydroxypropylated CyDs or sulfobutyl ether-beta-CyD (SBE7-beta-CyD) did not. Of methylated CyDs, 2,6-di-O-methyl-beta-cyclodextrin (DM-beta-CyD) and 2,3,6-tri-O-methyl-beta-cyclodextrin (TM-beta-CyD) markedly caused apoptosis in NR8383 cells, A549 cells and Jurkat cells, through cholesterol depletion in cell membranes. In sharp contrast, 2,6-di-O-methyl-alpha-cyclodextrin (DM-alpha-CyD) and methyl-beta-cyclodextrin (M-beta-CyD) induced cell death in an anti-apoptotic mechanism. DM-beta-CyD induced apoptosis through the inhibition of the activation of PI3K-Akt-Bad pathway. Neither p38 MAP kinase nor p53 was contributed to the induction of apoptosis by DM-beta-CyD. Additionally, DM-beta-CyD significantly decreased mitochondrial transmembrane potential, and then caused the release of cytochrome c from mitochondria to cytosol in NR8383 cells. Furthermore, we confirmed that down-regulation of pro-caspase-3 and activation of caspase-3 after incubation with DM-beta-CyD. These results suggest that of methylated CyDs, DM-beta-CyD, not DM-alpha-CyD, induces apoptosis through the PI3K-Akt-Bad pathway, resulting from cholesterol depletion in lipid rafts of cell membranes.

Effects of the prostaglandin E1 analog limaprost on mechanical allodynia caused by chemotherapeutic agents in mice.

This study examined in mice whether limaprost, a prostaglandin E(1) analog, would relieve allodynia induced by chemotherapeutic agents. Single intraperitoneal injections of paclitaxel, oxaliplatin, and vincristine sulfate induced and gradually increased mechanical allodynia. Repeated administration of limaprost alfadex inhibited the late, but not early, phase of mechanical allodynia induced by paclitaxel and oxaliplatin, but not vincristine. Paclitaxel and oxaliplatin, but not vincristine, gradually decreased peripheral blood flow, which was prevented by limaprost. These results suggest that limaprost is effective against mechanical allodynia induced by paclitaxel and oxaliplatin, which may be due to inhibition of the decrease in peripheral blood flow.

Inhibitory effects of 2,6-di-O-methyl-alpha-cyclodextrin on poly I:C signaling in macrophages.

In the present study, we examined the effects of alpha-cyclodextrin (alpha-CyD), 2-hydroxypropyl-alpha-cyclodextrin (HP-alpha-CyD) and 2,6-di-O-methyl-alpha-cyclodextrin (DM-alpha-CyD) on the nitric oxide (NO) and interferon-beta (IFN-beta) production in murine and human macrophages stimulated with Poly I:C and CpG-DNA, toll-like receptor 3 (TLR3) and TLR9 ligands, respectively. DM-alpha-CyD significantly inhibited NO production in RAW264.7 cells and U937 cells differentiated by phorbol myristate acetate (PMA), murine and human macrophage-like cell lines, respectively, stimulated with Poly I:C without cytotoxicity, but neither alpha-CyD nor HP-alpha-CyD did. Meanwhile, the three alpha-CyDs did not inhibit NO production in RAW264.7 cells stimulated with CpG-DNA. DM-alpha-CyD inhibited inducible NO synthase (iNOS) and IFN-beta expression upon stimulation with Poly I:C. Furthermore, DM-alpha-CyD markedly decreased the cellular uptake of Poly I:C in RAW264.7 cells. Therefore, DM-alpha-CyD may be useful as a potent inhibitor for excess activation of macrophages stimulated with Poly I:C.

Suppression of estrogenic activity of 17-beta-estradiol by beta-cyclodextrin.

The suppressive effects of cyclodextrins (CDs) on the strong estrogenic activity of 17beta-estradiol (E2) in water environments were investigated in this study. Cyclodextrins are doughnut-shaped molecules that possess a hydrophobic cavity and a hydrophilic exterior. The cavity can incorporate nonpolar molecules as guests to form inclusion complexes. beta-CD and 2-hydroxypropyl-beta-CD (HP-beta-CD) were the most successful in forming a complex with E2 and improving its low aqueous solubility. The E2/CDs complexes bound to the estrogen receptor in a cell-free system as determined by ELISA and suppressed the hormone activities as measured by a yeast two-hybrid assay. These results indicate that hydrophobic E2 is easily transported through the lipid zone of the plasma membrane into the target cell and can bind to the nuclear receptor. However, the hydrophilic E2/beta-CD and E2/HP-beta-CD complexes do not penetrate the membrane. Therefore, these CDs are able to suppress the hormone activity of E2 through complex formation.

Cyclodextrins inhibit replication of scrapie prion protein in cell culture.

Prion diseases are fatal neurodegenerative disorders that are caused by the conversion of a normal host-encoded protein, PrP(C), to an abnormal, disease-causing form, PrP(Sc). This paper reports that cyclodextrins have the ability to reduce the pathogenic isoform of the prion protein PrP(Sc) to undetectable levels in scrapie-infected neuroblastoma cells. Beta-cyclodextrin removed PrP(Sc) from the cells at a concentration of 500 microM following 2 weeks of treatment. Structure activity studies revealed that antiprion activity was dependent on the size of the cyclodextrin. The half-maximal inhibitory concentration (IC(50)) for beta-cyclodextrin was 75 microM, whereas alpha-cyclodextrin, which possessed less antiprion activity, had an IC(50) of 750 microM. This report presents cyclodextrins as a new class of antiprion compound. For decades, the pharmaceutical industry has successfully used cyclodextrins for their complex-forming ability; this ability is due to the structural orientation of the glucopyranose units, which generate a hydrophobic cavity that can facilitate the encapsulation of hydrophobic moieties. Consequently, cyclodextrins could be ideal candidates for the treatment of prion diseases.