Hyaluronan--magic glue for the regulation of the immune response?

Biomimetic Hyaluronan Binding Biomaterials to Capture the Complex Regulation of Hyaluronan in Tissue Development and Function

Within native ECM, Hyaluronan (HA) undergoes remarkable structural remodeling through its binding receptors and proteins called hyaladherins. Hyaladherins contain a group of tandem repeat sequences, such as LINK domains, BxB7 homologous sequences, or 20-50 amino acid long short peptide sequences that have high affinity towards side chains of HA. The HA binding sequences are critical players in HA distribution and regulation within tissues and potentially attractive therapeutic targets to regulate HA synthesis and organization. While HA is a versatile and successful biopolymer, most HA-based therapeutics have major differences from a native HA molecule, such as molecular weight discrepancies, crosslinking state, and remodeling with other HA binding proteins. Recent studies showed the promise of HA binding domains being used as therapeutic biomaterials for osteoarthritic, ocular, or cardiovascular therapeutic products. However, we propose that there is a significant potential for HA binding materials to reveal the physiological functions of HA in a more realistic setting. This review is focused on giving a comprehensive overview of the connections between HA's role in the body and the potential of HA binding material applications in therapeutics and regenerative medicine. We begin with an introduction to HA then discuss HA binding molecules and the process of HA binding. Finally, we discuss HA binding materials anf the future prospects of potential HA binding biomaterials systems in the field of biomaterials and tissue engineering.

Marine polysaccharides: Biological activities and applications in drug delivery systems

The ocean is the common home of a large number of marine organisms, including plants, animals, and microorganisms. Researchers can extract thousands of important bioactive components from the oceans and use them extensively to treat and prevent diseases. In contrast, marine polysaccharide macromolecules such as alginate, carrageenan, Laminarin, fucoidan, chitosan, and hyaluronic acid have excellent physicochemical properties, good biocompatibility, and high bioactivity, which ensures their wide applications and strong therapeutic potentials in drug delivery. Drug delivery systems (DDS) based on marine polysaccharides and modified marine polysaccharide molecules have emerged as an innovative technology for controlling drug distribution on temporal, spatial, and dosage scales. They can detect and respond to external stimuli such as pH, temperature, and electric fields. These properties have led to their wide application in the design of novel drug delivery systems such as hydrogels, polymeric micelles, liposomes, microneedles, microspheres, etc. In addition, marine polysaccharide-based DDS not only have smart response properties but also can combine with the unique biological properties of the marine polysaccharide base to exert synergistic therapeutic effects. The biological activities of marine polysaccharides and the design of marine polysaccharide-based DDS are reviewed. Marine polysaccharide-based responsive DDS are expected to provide new strategies and solutions for disease treatment.

New insights into the role of glycosaminoglycans in the endosteal bone microenvironment

The bone microenvironment is a complex tissue in which heterogeneous cell populations of hematopoietic and mesenchymal origin interact with environmental cues to maintain tissue integrity. Both cellular and matrix components are subject to physiologic challenges and can dynamically respond by modifying cell/matrix interactions. When either component is impaired, the physiologic balance is lost. Here, we review the current state of knowledge of how glycosaminoglycans - organic components of the bone extracellular matrix - influence the bone micromilieu. We point out how they interact with mediators of distinct signaling pathways such as the RANKL/OPG axis, BMP and WNT signaling, and affect the activity of bone remodeling cells within the endosteal niche summarizing their potential for therapeutic intervention.

A Combined Self-Assembled Drug Delivery for Effective Anti-Breast Cancer Therapy

AIM

The metastasis of breast cancer is an important cause of tumor recurrence. This study highlights that tyrosine kinase inhibitors dasatinib (DAS) and rosiglitazone (ROZ) inhibit tumor growth and reduce the occurrence of tumor cell metastasis. Due to the poor water solubility, short half-time in the body of DAS and ROZ, which increases the difficulty of tumor treatment, as well as the demand for nano-drug delivery systems for organ-specific therapies.

METHODS

Hyaluronic acid (HA) and DAS are bonded by a pH-sensitive ester bond to form an HA-DAS polymer. Then, ROZ was added as the core, D-A-tocopherol polydiethylene glycol isosuccinate (TPGS) and HA-DAS were used as carriers to form HA-DAS and TPGS mixed micelle system loaded with ROZ (THDR-NPs). The size and structure of THDR-NPs were characterized, the drug release, stability and biosafety of THDR-NPs were studied. In vitro, the cytotoxicity, targeting effect and tumor metastasis inhibition of THDR-NPs were evaluated in human breast cancer cell lines. In addition, the selective potency of designed THDR-NPs in depleting was further verified in vivo in the tumor-bearing nude mice model.

RESULTS

The designed THDR-NPs have a particle size of less than 100 nm, good stability, biological safety and sustained release, and showed strong therapeutic effects on breast cancer models in vitro and in vivo. Moreover, it has been proved that THDR-NPs have the ability to inhibit tumor metastasis.

CONCLUSION

DAS and ROZ were designed into micelles, the efficacy of THDR-NPs was higher than that of free drugs. These results indicate that nanoparticles have a good application prospect in the treatment of tumor metastasis.

CD44 and Tumor-Derived Extracellular Vesicles (TEVs). Possible Gateway to Cancer Metastasis

Cancer metastasis, the final stage of tumor progression, is a complex process governed by the interplay of multiple types of cells and the tumor microenvironment. One of the aspects of this interplay involves the release of various factors by the tumor cells alone or by forcing other cells to do so. As a consequence of these actions, tumor cells are prepared in favorable conditions for their dissemination and spread to other sites/organs, which guarantees their escape from immunosurveillance and further progression. Tumor-derived extracellular vesicles (TEVs) represent a heterogeneous population of membrane-bound vesicles that are being actively released by different tumors. The array of proteins (i.e., receptors, cytokines, chemokines, etc.) and nucleic acids (i.e., mRNA, miR, etc.) that TEVs can transfer to other cells is often considered beneficial for the tumor’s survival and proliferation. One of the proteins that is associated with many different tumors as well as their TEVs is a cluster of differentiation 44 in its standard (CD44s) and variant (CD44v) form. This review covers the present information regarding the TEVs-mediated CD44s/CD44v transfer/interaction in the context of cancer metastasis. The content and the impact of the transferred cargo by this type of TEVs also are discussed with regards to tumor cell dissemination.

The scrambled story between hyaluronan and glioblastoma

Advances in cancer biology are revealing the importance of the cancer cell microenvironment on tumorigenesis and cancer progression. Hyaluronan (HA), the main glycosaminoglycan in the extracellular matrix, has been associated with the progression of glioblastoma (GBM), the most frequent and lethal primary tumor in the central nervous system, for several decades. However, the mechanisms by which HA impacts GBM properties and processes have been difficult to elucidate. In this review, we provide a comprehensive assessment of the current knowledge on HA's effects on GBM biology, introducing its primary receptors CD44 and RHAMM and the plethora of relevant downstream signaling pathways that can scramble efforts to directly link HA activity to biological outcomes. We consider the complexities of studying an extracellular polymer and the different strategies used to try to capture its function, including 2D and 3D in vitro studies, patient samples, and in vivo models. Given that HA affects not only migration and invasion, but also cell proliferation, adherence, and chemoresistance, we highlight the potential role of HA as a therapeutic target. Finally, we review the different existing approaches to diminish its protumor effects, such as the use of 4-methylumbelliferone, HA oligomers, and hyaluronidases and encourage further research along these lines in order to improve the survival and quality of life of GBM patients.

4-Methylumbelliferone as a potent and selective antitumor drug on a glioblastoma model

Glioblastoma (GBM), the most frequent primary tumor of the central nervous system, has a median survival of 14.6 months. 4-Methylumbelliferone (4MU) is a coumarin derivative widely used as a hyaluronan synthesis inhibitor with proven antitumor activity and without toxic effects reported. We aim to evaluate the antitumor effect of 4MU alone or combined with temozolomide (TMZ) on a GBM cell line, its absence of toxicity on brain cells and its selectivity for tumor cells. The antitumor effect of 4MU alone or combined with TMZ was evaluated on GL26 cells by assessing the metabolic activity through the XTT assay, cell proliferation by BrdU incorporation assay, migration by the wound healing assay, cell death by fluorescein diacetate/propidium iodide (FDA/PI) staining, apoptosis by membrane asymmetry and DNA fragmentation and metalloproteinase activity by zymography. The levels of hyaluronan and its capacity to counteract the effects of 4MU and the expression of RHAMM and CD44 were also determined. The toxicity and selectivity of 4MU were determined by XTT assay and PI staining on normal brain primary cell culture (NBPC-GFP) and GL26/NBPC-GFP cocultures. The GL26 cells expressed RHAMM but not CD44 while synthetized hyaluronan. 4MU decreased hyaluronan synthesis, diminished proliferation and induced apoptosis while reducing cell migration and the activity of metalloproteinases, which was restored by addition of hyaluronic acid. Furthermore, 4MU sensitized GL26 cells to the TMZ effect and showed selective toxicity on tumor cells without exhibiting neurotoxic effects. We demonstrated for the first time the cytotoxic effect of 4MU on GBM cells, highlighting its potential usefulness to improve GBM treatment.

A Low Molecular Weight Hyaluronic Acid Derivative Accelerates Excisional Wound Healing by Modulating Pro-Inflammation, Promoting Epithelialization and Neovascularization, and Remodeling Collagen

Recent knowledge of the cellular and molecular mechanisms underlying cutaneous wound healing has advanced the development of medical products. However, patients still suffer from the failure of current treatments, due to the complexity of healing process and thus novel therapeutic approaches are urgently needed. Previously, our laboratories produced a range of low molecular weight hyaluronic acid (LMW-HA) fragments, where a proportion of the glucosamine moieties were chemically N-acyl substituted. Specifically, N-butyrylation results in anti-inflammatory properties in a macrophage system, and we demonstrate the importance of N-acyl substituents in modulating the inflammatory response of LMW-HA. We have set up an inter-institutional collaborative program to examine the biomedical applications of the N-butyrylated LMW-HA (BHA). In this study, the potentials of BHA for dermal healing are assessed in vitro and in vivo. Consequently, BHA significantly promotes dermal healing relative to a commercial wound care product. By contrast, the “parent” partially de-acetylated LMW-HA (DHA) and the re-acetylated DHA (AHA) significantly delays wound closure, demonstrating the specificity of this N-acylation of LMW-HA in wound healing. Mechanistic studies reveal that the BHA-mediated therapeutic effect is achieved by targeting three phases of wound healing (i.e., inflammation, proliferation and maturation), demonstrating the significant potential of BHA for clinical translation in cutaneous wound healing.

Revisiting the hallmarks of cancer: The role of hyaluronan

Extracellular matrix (ECM) is a complex network of macromolecules such as proteoglycans (PGs), glycosaminoglycans (GAGs) and fibrous proteins present within all tissues and organs. The main role of ECM is not only to provide an essential mechanical scaffold for the cells but also to mediate crucial biochemical cues that are required for tissue homeostasis. Dysregulations in ECM deposition alter cell microenvironment, triggering the onset or the rapid progression of several diseases, including cancer. Hyaluronan (HA) is a ubiquitous component of ECM considered as one of the main players of cancer initiation and progression. This review discusses how HA participate in and regulate several aspects of tumorigenesis, with particular attention to the hallmarks of cancer proposed by Hanahan and Weinberg such as sustaining of the proliferative signaling, evasion of apoptosis, angiogenesis, activation of invasion and metastases, reprogramming of energy metabolism and evasion of immune response.

Oligo Hyaluronan-Coated Silica/Hydroxyapatite Degradable Nanoparticles for Targeted Cancer Treatment

Targeted drug delivery systems (TDDSs) provide a promising approach to overcome the side effect of traditional chemotherapy by specific tumor targeting and drug release. Hyaluronan (HA), as a selective CD44 targeting group, has been widely used in TDDSs for chemotherapy. However, different molecular weight HAs would demonstrate different binding ability to CD44, which may result in different therapeutic effects. Herein, a silica/hydroxyapatite (MSNs/HAP) hybrid carrier loaded with anticancer drug doxorubicin (DOX) (DOX@MSNs/HAP) is fabricated. HA and oligo HA (oHA) are coated onto the nanoparticles (HA-DOX@MSNs/HAP, oHA-DOX@MSNs/HAP), respectively, to investigate their performance in tumor targeting ability. oHA-DOX@MSNs/HAP shows much higher efficiency cellular uptake and drug release in tumor regions due to more effective CD44 targeting of oHA. Thus, the anticancer effect of oHA-DOX@MSNs/HAP is significantly enhanced compared to HA-DOX@MSNs/HAP, as demonstrated in a tumor-bearing mouse model. This study may enable the rational design of nanodrug systems for future tumor-targeted chemotherapy.

Hyaluronic Acid: Molecular Mechanisms and Therapeutic Trajectory

Hyaluronic acid (also known as hyaluronan or hyaluronate) is naturally found in many tissues and fluids, but more abundantly in articular cartilage and synovial fluid (SF). Hyaluronic acid (HA) content varies widely in different joints and species. HA is a non-sulfated, naturally occurring non-protein glycosaminoglycan (GAG), with distinct physico-chemical properties, produced by synoviocytes, fibroblasts, and chondrocytes. HA has an important role in the biomechanics of normal SF, where it is partially responsible for lubrication and viscoelasticity of the SF. The concentration of HA and its molecular weight (MW) decline as osteoarthritis (OA) progresses with aging. For that reason, HA has been used for more than four decades in the treatment of OA in dogs, horses and humans. HA produces anti-arthritic effects via multiple mechanisms involving receptors, enzymes and other metabolic pathways. HA is also used in the treatment of ophthalmic, dermal, burns, wound repair, and other health conditions. The MW of HA appears to play a critical role in the formulation of the products used in the treatment of diseases. This review provides a mechanism-based rationale for the use of HA in some disease conditions with special reference to OA.

4-Methylumbelliferyl glucuronide contributes to hyaluronan synthesis inhibition

4-Methylumbelliferone (4-MU) inhibits hyaluronan (HA) synthesis and is an approved drug used for managing biliary spasm. However, rapid and efficient glucuronidation is thought to limit its utility for systemically inhibiting HA synthesis. In particular, 4-MU in mice has a short half-life, causing most of the drug to be present as the metabolite 4-methylumbelliferyl glucuronide (4-MUG), which makes it remarkable that 4-MU is effective at all. We report here that 4-MUG contributes to HA synthesis inhibition. We observed that oral administration of 4-MUG to mice inhibits HA synthesis, promotes FoxP3⁺ regulatory T-cell expansion, and prevents autoimmune diabetes. Mice fed either 4-MUG or 4-MU had equivalent 4-MU:4-MUG ratios in serum, liver, and pancreas, indicating that 4-MU and 4-MUG reach an equilibrium in these tissues. LC-tandem MS experiments revealed that 4-MUG is hydrolyzed to 4-MU in serum, thereby greatly increasing the effective bioavailability of 4-MU. Moreover, using intravital 2-photon microscopy, we found that 4-MUG (a nonfluorescent molecule) undergoes conversion into 4-MU (a fluorescent molecule) and that 4-MU is extensively tissue bound in the liver, fat, muscle, and pancreas of treated mice. 4-MUG also suppressed HA synthesis independently of its conversion into 4-MU and without depletion of the HA precursor UDP-glucuronic acid (GlcUA). Together, these results indicate that 4-MUG both directly and indirectly inhibits HA synthesis and that the effective bioavailability of 4-MU is higher than previously thought. These findings greatly alter the experimental and therapeutic possibilities for HA synthesis inhibition.

Tissue microenvironment initiates an immune response to structural components of Staphylococcus aureus

Cell-to-cell communication in skin participates to the maintenance of homeostatic responses to foreign substances. Certain strains of Staphylococcus (S) aureus are vicious pathogens that cause deleterious effects in host cells and tissues. Both secreted toxins and structural components of S. aureus trigger an immune response, though how S. aureus stimulates host immune responses is poorly understood. We explored here how keratinocytes and fibroblasts initiate the first steps of an immune response by activating dendritic cells (DCs) through recognition of structural components of S. aureus. We treated monocyte-derived Langerhans cells (moLCs) and monocyte-derived DCs (moDCs) with conditioned media from keratinocytes (K-CM) and fibroblasts (F-CM) treated with heat-killed S. aureus (HKSA) respectively, or directly with HKSA. Immune and inflammatory responses from keratinocytes, fibroblasts, moLCs and moDCs were assessed by analysis of cell surface markers and cytokine production using flow cytometry, real-time PCR and ELISA assays. K-CM and F-CM increased the expression of CD86 and HLA-DR on moLCs and moDCs, in association with a specific cytokine profile. K-CM upregulated TNFA, IL-1B and GM-CSF mRNA expression in moLCs, while F-CM upregulated IL-12 and downregulated TNFA and TGFB mRNA expression in moDCs. Additionally, F-CM attenuated the induction of an inflammatory profile in monocytes. The recognition of structural components from S. aureus by cutaneous microenvironment induces the activation and the expression of specific cytokines from LCs and DCs.

High molecular weight hyaluronan protects cartilage from degradation by inhibiting aggrecanase expression

Hyaluronan (HA) is an extracellular matrix (ECM) component of articular cartilage and has been used to treat patients with osteoarthritis (OA). A disintegrin and metalloproteinases with thrombospondin motifs (ADAMTSs) play an important role in cartilage degradation in OA. We have previously reported that ADAMTS4 and ADAMTS9 were induced by cytokine stimulation. However, the effect of HA on the cytokine-inducible ADAMTS9 has never been investigated. Moreover, it is unclear whether HA protects cartilage by suppressing aggrecan degradation. Here, we examined the effects of HA on ADAMTS expression in vitro and on cartilage degradation in vivo. ADAMTS9 expression was higher than that of the other aggrecanases (ADAMTS4 and 5) in human chondrocytes, chondrocytic cells, and rat cartilage. ADAMTS4 and 9 mRNA levels were upregulated in cytokine-stimulated chondrocytes and chondrocytic cells. Pre-incubation with HA significantly inhibited ADAMTS9 mRNA expression in cytokine-stimulated cells. In a rat OA model, Adamts5 and 9 mRNA levels were transiently increased after surgery; intra-articular HA injections attenuated the induction of Adamts5 and 9 mRNA. HA also blocked aggrecan cleavage by aggrecanase in OA rats in a molecular size-dependent manner. These results demonstrate that HA attenuates induced aggrecanases expression in OA and thereby protects articular cartilage degradation by this enzyme. Our findings provide insight into the molecular basis for the beneficial effects of HA in OA. © 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 36:3247-3255, 2018.

Hyaluronan-based dissolving microneedles with high antigen content for intradermal vaccination: Formulation, physicochemical characterization and immunogenicity assessment

The purpose of this study was to optimize the manufacturing of dissolving microneedles (dMNs) and to increase the antigen loading in dMNs to investigate the effect on their physicochemical properties. To achieve this, a novel single-array wells polydimethylsiloxane mold was designed, minimizing antigen wastage during fabrication and achieving homogeneous antigen distribution among the dMN arrays. Using this mold, hyaluronan (HA)-based dMNs were fabricated and tested for maximal ovalbumin (OVA) content. dMNs could be fabricated with an OVA:HA ratio as high as 1:1 (w/w), without compromising their properties such as shape and penetration into the ex vivo human skin, even after storage at high humidity and temperature. High antigen loading did not induce protein aggregation during dMN fabrication as demonstrated by complementary analytical methods. However, the dissolution rate in ex vivo human skin decreased with increasing antigen loading. About 2.7 µg OVA could be delivered in mice by using a single array with an OVA:HA ratio of 1:3 (w/w). Intradermal vaccination with dMNs induced an immune response similar as subcutaneous injection and faster than after hollow microneedle injection. In conclusion, results suggest that (i) the polydimethylsiloxane mold design has an impact on the manufacturing of dMNs, (ii) the increase in antigen loading in dMNs affects the microneedle dissolution and (iii) dMNs are a valid alternative for vaccine administration over conventional injection.

Pursuing Intracellular Pathogens with Hyaluronan. From a 'Pro-Infection' Polymer to a Biomaterial for 'Trojan Horse' Systems

Hyaluronan (HA) is among the most important bioactive polymers in mammals, playing a key role in a number of biological functions. In the last decades, it has been increasingly studied as a biomaterial for drug delivery systems, thanks to its physico-chemical features and ability to target and enter certain cells. The most important receptor of HA is ‘Cluster of Differentiation 44’ (CD44), a cell surface glycoprotein over-expressed by a number of cancers and heavily involved in HA endocytosis. Moreover, CD44 is highly expressed by keratinocytes, activated macrophages and fibroblasts, all of which can act as ‘reservoirs’ for intracellular pathogens. Interestingly, both CD44 and HA appear to play a key role for the invasion and persistence of such microorganisms within the cells. As such, HA is increasingly recognised as a potential target for nano-carriers development, to pursuit and target intracellular pathogens, acting as a ‘Trojan Horse’. This review describes the biological relationship between HA, CD44 and the entry and survival of a number of pathogens within the cells and the subsequent development of HA-based nano-carriers for enhancing the intracellular activity of antimicrobials.

Hyaluronan in immune dysregulation and autoimmune diseases

The tissue microenvironment contributes to local immunity and to the pathogenesis of autoimmune diseases - a diverse set of conditions characterized by sterile inflammation, immunity against self-antigens, and destruction of tissues. However, the specific factors within the tissue microenvironment that contribute to local immune dysregulation in autoimmunity are poorly understood. One particular tissue component implicated in multiple autoimmune diseases is hyaluronan (HA), an extracellular matrix (ECM) polymer. HA is abundant in settings of chronic inflammation and contributes to lymphocyte activation, polarization, and migration. Here, we first describe what is known about the size, amount, and distribution of HA at sites of autoimmunity and in associated lymphoid structures in type 1 diabetes, multiple sclerosis, and rheumatoid arthritis. Next, we examine the recent literature on HA and its impact on adaptive immunity, particularly in regards to the biology of lymphocytes and Foxp3+ regulatory T-cells (Treg), a T-cell subset that maintains immune tolerance in healthy individuals. We propose that HA accumulation at sites of chronic inflammation creates a permissive environment for autoimmunity, characterized by CD44-mediated inhibition of Treg expansion. Finally, we address potential tools and strategies for targeting HA and its receptor CD44 in chronic inflammation and autoimmunity.

Absence of differences among low, middle, and high molecular weight hyaluronan in activating murine immune cells in vitro

Hyaluronan (HA) effects on immune response are suggested to be dependent on HA molecular weight (MW), as low MW HA should activate immune cells in contrast to high MW HA. However, some current studies do not support this conception and emphasize the importance of the form of preparation of HA, particularly with respect to its purity and origin. We compared the activation of mouse immune cells by HA samples (100kDa, 500kDa, and 997kDa) prepared from HA originating from rooster comb, and HA samples (71kDa, 500kDa, and 1000kDa) prepared from pharmacological grade HA originating from Streptococcus equi. Interestingly, in contrast to established theory, only middle and high MW HA originating from rooster comb induced the production of tumor necrosis factor-α by macrophages and in whole blood. Further, all tested preparations of HA failed to induce the expression of inducible nitric oxide synthase, the production of nitric oxide, or the expression of cyclooxygenase 2 in macrophages and splenocytes. Importantly, all HA samples originating from rooster comb were found to be contaminated by endotoxin (up to 1.23EU/ml). Hence, low MW HA did not reveal itself to have significantly higher immunostimulatory activity compared to HA of higher MW.

The pharmacokinetics and dosing of oral 4-methylumbelliferone for inhibition of hyaluronan synthesis in mice

Recently, there has been considerable interest in using 4-methylumbelliferone (4-MU) to inhibit hyaluronan (HA) synthesis in mouse models of cancer, autoimmunity and a variety of other inflammatory disorders where HA has been implicated in disease pathogenesis. In order to facilitate future studies in this area, we have examined the dosing, treatment route, treatment duration and metabolism of 4-MU in both C57BL/6 and BALB/c mice. Mice fed chow containing 5% 4-MU, a dose calculated to deliver 250 mg/mouse/day, initially lose substantial weight but typically resume normal weight gain after 1 week. It also takes up to a week to see a reduction in serum HA in these animals, indicating that at least a 1-week loading period on the drug is required for most protocols. At steady state, more than 90% of the drug is present in plasma as the glucuronidated metabolite 4-methylumbelliferyl glucuronide (4-MUG), with the sulphated metabolite, 4-methylumbelliferyl sulphate (4-MUS) comprising most of the remainder. Chow containing 5% but not 0·65% 4-MU was effective at preventing disease in the experimental autoimmune encephalomyelitis (EAE) mouse model of multiple sclerosis, as well as in the DORmO mouse model of autoimmune diabetes. While oral 4-MU was effective at preventing EAE, daily intraperitoneal injections of 4-MU were not. Factors potentially affecting 4-MU uptake and plasma concentrations in mice include its taste, short half-life and low bioavailability. These studies provide a practical resource for implementing oral 4-MU treatment protocols in mice.

Hydrolysis of Hyaluronic Acid in Lymphedematous Tissue Alleviates Fibrogenesis via TH1 Cell-Mediated Cytokine Expression

Although surgery and radiation are beneficial for treating cancer, they can also lead to malfunctions of the lymphatic system such as secondary lymphedema. This abnormality of the lymphatic system is characterized by severe swelling, adipogenesis, inflammation, and fibrosis in the lymphedematous region. Moreover, the proliferation of fibrotic tissue in the lymphedematous region generates edema that is no longer spontaneously reversible. No treatment for fibrosis has been validated in patients with lymphedema. In our efforts to develop a therapeutic agent for lymphedema fibrosis, we used a newly established mouse hind limb model. Previous studies have demonstrated that hyaluronic acid accumulates in the lymphedematous region. Thus, we challenged mice with of hyaluronidase (HYAL), with the aim of reducing fibrogenesis. After subcutaneous injections in the lymphedematous mouse leg every two days, the volume of lymphedema had reduced significantly by 7 days post-operation. Histochemical analysis indicated that collagen accumulation and myofibroblast differentiation were decreased in epidermal tissues after HYAL injection. Moreover, it was associated with upregulation of interferon-gamma, increased numbers of Th1 cells, and downregulation of interleukin-4 and interleukin-6 in the lymphedematous region and spleen. These results indicate that hydrolysis of hyaluronic acid can boost an anti-fibrotic immune response in the mouse lymphedema model.

Chlorinated Phospholipids and Fatty Acids: (Patho)physiological Relevance, Potential Toxicity, and Analysis of Lipid Chlorohydrins

Chlorinated phospholipids are formed by the reaction of hypochlorous acid (HOCl), generated by the enzyme myeloperoxidase under inflammatory conditions, and the unsaturated fatty acyl residues or the head group. In the first case the generated chlorohydrins are both proinflammatory and cytotoxic, thus having a significant impact on the structures of biomembranes. The latter case leads to chloramines, the properties of which are by far less well understood. Since HOCl is also widely used as a disinfecting and antibacterial agent in medicinal, industrial, and domestic applications, it may represent an additional source of danger in the case of abuse or mishandling. This review discusses the reaction behavior of in vivo generated HOCl and biomolecules like DNA, proteins, and carbohydrates but will focus on phospholipids. Not only the beneficial and pathological (toxic) effects of chlorinated lipids but also the importance of these chlorinated species is discussed. Some selected cleavage products of (chlorinated) phospholipids and plasmalogens such as lysophospholipids, (chlorinated) free fatty acids and α-chloro fatty aldehydes, which are all well known to massively contribute to inflammatory diseases associated with oxidative stress, will be also discussed. Finally, common analytical methods to study these compounds will be reviewed with focus on mass spectrometric techniques.

Targeting Tumor Cells with Anti-CD44 Antibody Triggers Macrophage-Mediated Immune Modulatory Effects in a Cancer Xenograft Model

CD44, a transmembrane receptor reported to be involved in various cellular functions, is overexpressed in several cancer types and supposed to be involved in the initiation, progression and prognosis of these cancers. Since the sequence of events following the blockage of the CD44-HA interaction has not yet been studied in detail, we profiled xenograft tumors by RNA Sequencing to elucidate the mode of action of the anti-CD44 antibody RG7356. Analysis of tumor and host gene-expression profiles led us to the hypothesis that treatment with RG7356 antibody leads to an activation of the immune system. Using cytokine measurements we further show that this activation involves the secretion of chemo-attractants necessary for the recruitment of immune cells (i.e. macrophages) to the tumor site. We finally provide evidence for antibody-dependent cellular phagocytosis (ADCP) of the malignant cells by macrophages.

Hyaluronan Modulation Impacts Staphylococcus aureus Biofilm Infection

Staphylococcus aureus is a leading cause of chronic biofilm infections. Hyaluronic acid (HA) is a large glycosaminoglycan abundant in mammalian tissues that has been shown to enhance biofilm formation in multiple Gram-positive pathogens. We observed that HA accumulated in an S. aureus biofilm infection using a murine implant-associated infection model and that HA levels increased in a mutant strain lacking hyaluronidase (HysA). S. aureus secretes HysA in order to cleave HA during infection. Through in vitro biofilm studies with HA, the hysA mutant was found to accumulate increased biofilm biomass compared to the wild type, and confocal microscopy showed that HA is incorporated into the biofilm matrix. Exogenous addition of purified HysA enzyme dispersed HA-containing biofilms, while catalytically inactive enzyme had no impact. Additionally, induction of hysA expression prevented biofilm formation and also dispersed an established biofilm in the presence of HA. These observations were corroborated in the implant model, where there was decreased dissemination from an hysA mutant biofilm infection compared to the S. aureus wild type. Histopathology demonstrated that infection with an hysA mutant caused significantly reduced distribution of tissue inflammation compared to wild-type infection. To extend these studies, the impact of HA and S. aureus HysA on biofilm-like aggregates found in joint infections was examined. We found that HA contributes to the formation of synovial fluid aggregates, and HysA can disrupt aggregate formation. Taken together, these studies demonstrate that HA is a relevant component of the S. aureus biofilm matrix and HysA is important for dissemination from a biofilm infection.

Hyaluronan as a therapeutic target in human diseases

Accumulation and turnover of extracellular matrix is a hallmark of tissue injury, repair and remodeling in human diseases. Hyaluronan is a major component of the extracellular matrix and plays an important role in regulating tissue injury and repair, and controlling disease outcomes. The function of hyaluronan depends on its size, location, and interactions with binding partners. While fragmented hyaluronan stimulates the expression of an array of genes by a variety of cell types regulating inflammatory responses and tissue repair, cell surface hyaluronan provides protection against tissue damage from the environment and promotes regeneration and repair. The interactions of hyaluronan and its binding proteins participate in the pathogenesis of many human diseases. Thus, targeting hyaluronan and its interactions with cells and proteins may provide new approaches to developing therapeutics for inflammatory and fibrosing diseases. This review focuses on the role of hyaluronan in biological and pathological processes, and as a potential therapeutic target in human diseases.

Hyaluronidase Activity in Saliva of European Culicoides (Diptera: Ceratopogonidae)

Biting midges of the genus Culicoides transmit pathogens of veterinary importance such as bluetongue virus (Reoviridae: Orbivirus). The saliva of Culicoides is known to contain bioactive molecules including peptides and proteins with vasodilatory and immunomodulative properties. In this study, we detected activity of enzyme hyaluronidase in six Culicoides species that commonly occur in Europe and that are putative vectors of arboviruses. Hyaluronidase was present in all species studied, although its molecular size, sensitivity to SDS, and substrate specificity differed between species. Further studies on the potential effect of hyaluronidase activity on the vector competence of Culicoides species for arboviruses would be beneficial.

Sequence diversity and ligand-induced structural rearrangements of viper hyaluronidase

The study focuses on ligand-induced structural changes of viper hyaluronidase and also provides insight into structure-based drug design for eukaryotic hyaluronidases, which could be future drug targets in cancer treatment, and venom spreading.

Advances and advantages of nanomedicine in the pharmacological targeting of hyaluronan-CD44 interactions and signaling in cancer

Extensive experimental evidence in cell and animal tumor models show that hyaluronan-CD44 interactions are crucial in both malignancy and resistance to cancer therapy. Because of the intimate relationship between the hyaluronan-CD44 system and tumor cell survival and growth, it is an increasingly investigated area for applications to anticancer chemotherapeutics. Interference with the hyaluronan-CD44 interaction by targeting drugs to CD44, targeting drugs to the hyaluronan matrix, or interfering with hyaluronan matrix/tumor cell-associated CD44 interactions is a viable strategy for cancer treatment. Many of these methods can decrease tumor burden in animal models but have yet to show significant clinical utility. Recent advances in nanomedicine have offered new valuable tools for cancer detection, prevention, and treatment. The enhanced permeability and retention effect has served as key rationale for using nanoparticles to treat solid tumors. However, the targeted and uniform delivery of these particles to all regions of tumors in sufficient quantities requires optimization. An ideal nanocarrier should be equipped with selective ligands that are highly or exclusively expressed on target cells and thus endow the carriers with specific targeting capabilities. In this review, we describe how the hyaluronan-CD44 system may provide such an alternative in tumors expressing specific CD44 variants.

Cancer microenvironment and inflammation: role of hyaluronan

The role of inflammation in the development of cancer was described as early as the nineteenth century. Abundant evidence supports the preposition that various cancers are triggered by infection and chronic inflammatory disease whereas, evading immune destruction has been proposed as one of the new “hallmarks of cancer.” Changes of the tumor microenvironment have been closely correlated to cancer-mediated inflammation. Hyaluronan (HA), an important extracellular matrices component, has become recognized as an active participant in inflammatory, angiogenic, fibrotic, and cancer promoting processes. This review discusses how HA and specific HA-binding proteins participate in and regulate cancer-related inflammatory processes.

More than just a filler - the role of hyaluronan for skin homeostasis

In recent years, hyaluronan (HA) has become an increasingly attractive substance as a non-immunogenic filler and scaffolding material in cosmetic dermatology. Despite its wide use for skin augmentation and rejuvenation, relatively little is known about the molecular structures and interacting proteins of HA in normal and diseased skin. However, a comprehensive understanding of cutaneous HA homeostasis is required for future the development of HA-based applications for skin regeneration. This review provides an update on HA-based structures, expression, metabolism and its regulation, function and pharmacological targeting of HA in skin.

Glycosaminoglycan degradation by selected reactive oxygen species

SIGNIFICANCE

Inflammatory diseases (such as arthritis) of the extracellular matrix (ECM) are of considerable socioeconomic significance. There is clear evidence that reactive oxygen species (ROS) and nitrogen species released by, for instance, neutrophils contribute to the degradation of the ECM. Here we will focus on the ROS-induced degradation of the glycosaminoglycans, one important component of the ECM.

RECENT ADVANCES

The recently developed "anti-TNF-α" therapy is primarily directed against neutrophilic granulocytes that are powerful sources of ROS. Therefore, a more detailed look into the mechanisms of the reactions of these ROS is reasonable.

CRITICAL ISSUES

Since both enzymes and ROS contribute to the pathogenesis of inflammatory diseases, it is very difficult to estimate the contributions of the individual species in a complex biological environment. This particularly applies as many products are not stable but only transient products that decompose in a time-dependent manner. Thus, the development of suitable analytical methods as well as the establishment of useful biomarkers is a challenging aspect.

FUTURE DIRECTIONS

If the mechanisms of ECM destruction are understood in more detail, then the development of suitable drugs to treat inflammatory diseases will be hopefully much more successful.

Hyaluronan and hyaluronan-binding proteins accumulate in both human type 1 diabetic islets and lymphoid tissues and associate with inflammatory cells in insulitis

Hyaluronan (HA) is an extracellular matrix glycosaminoglycan that is present in pancreatic islets, but little is known about its involvement in the development of human type 1 diabetes (T1D). We have evaluated whether pancreatic islets and lymphoid tissues of T1D and nondiabetic organ donors differ in the amount and distribution of HA and HA-binding proteins (hyaladherins), such as inter-α-inhibitor (IαI), versican, and tumor necrosis factor-stimulated gene-6 (TSG-6). HA was dramatically increased both within the islet and outside the islet endocrine cells, juxtaposed to islet microvessels in T1D. In addition, HA was prominent surrounding immune cells in areas of insulitis. IαI and versican were present in HA-rich areas of islets, and both molecules accumulated in diabetic islets and regions exhibiting insulitis. TSG-6 was observed within the islet endocrine cells and in inflammatory infiltrates. These patterns were only observed in tissues from younger donors with disease duration of <10 years. Furthermore, HA and IαI amassed in follicular germinal centers and in T-cell areas in lymph nodes and spleens in T1D patients compared with control subjects. Our observations highlight potential roles for HA and hyaladherins in the pathogenesis of diabetes.

Transactivation of the receptor-tyrosine kinase ephrin receptor A2 is required for the low molecular weight hyaluronan-mediated angiogenesis that is implicated in tumor progression

Angiogenesis or the formation of new blood vessels is important in the growth and metastatic potential of various cancers. Therefore, understanding the mechanism(s) by which angiogenesis occurs can have important therapeutic implications in numerous malignancies. We and others have demonstrated that low molecular weight hyaluronan (LMW-HA, ∼2500 Da) promotes endothelial cell (EC) barrier disruption and angiogenesis. However, the mechanism(s) by which this occurs is poorly defined. Our data indicate that treatment of human EC with LMW-HA induced CD44v10 association with the receptor-tyrosine kinase, EphA2, transactivation (tyrosine phosphorylation) of EphA2, and recruitment of the PDZ domain scaffolding protein, PATJ, to the cell periphery. Silencing (siRNA) CD44, EphA2, PATJ, or Dbs (RhoGEF) expression blocked LMW-HA-mediated angiogenesis (EC proliferation, migration, and tubule formation). In addition, silencing EphA2, PATJ, Src, or Dbs expression blocked LMW-HA-mediated RhoA activation. To translate our in vitro findings, we utilized a novel anginex/liposomal targeting of murine angiogenic endothelium with either CD44 or EphA2 siRNA and observed inhibition of LMW-HA-induced angiogenesis in implanted Matrigel plugs. Taken together, these results indicate LMW-HA-mediated transactivation of EphA2 is required for PATJ and Dbs membrane recruitment and subsequent RhoA activation required for angiogenesis. These results suggest that targeting downstream effectors of LMW-HA could be a useful therapeutic intervention for angiogenesis-associated diseases including tumor progression.

Improvement of the digestibility of sulfated hyaluronans by bovine testicular hyaluronidase: a UV spectroscopic and mass spectrometric study

Glycosaminoglycans (GAGs) such as hyaluronan (HA) and chondroitin sulfate (CS) are important, natural polysaccharides which occur in biological (connective) tissues and have various biotechnological and medical applications. Additionally, there is increasing evidence that chemically (over)sulfated GAGs possess promising properties and are useful as implant coatings. Unfortunately, a detailed characterization of these GAGs is challenging: although mass spectrometry (MS) is one of the most powerful tools to elucidate the structures of (poly)saccharides, MS is not applicable to high mass polysaccharides, but characteristic oligosaccharides are needed. These oligosaccharides are normally generated by enzymatic digestion. However, chemically modified (particularly sulfated) GAGs are extremely refractive to enzymatic digestion. This study focuses on the investigation of the digestibility of GAGs with different degrees of sulfation by bovine testicular hyaluronidase (BTH). It will be shown by using an adapted spectrophotometric assay that all investigated GAGs can be basically digested if the reaction conditions are carefully adjusted. However, the oligosaccharide yield correlates reciprocally with the number of sulfate residues per polymer repeating unit. Finally, matrix-laser desorption and ionization (MALDI) MS will be used to study the released oligosaccharides and their sulfation patterns.

Hyaluronan digestion controls DC migration from the skin

The breakdown and release of hyaluronan (HA) from the extracellular matrix has been hypothesized to act as an endogenous signal of injury. To test this hypothesis, we generated mice that conditionally overexpressed human hyaluronidase 1 (HYAL1). Mice expressing HYAL1 in skin either during early development or by inducible transient expression exhibited extensive HA degradation, yet displayed no evidence of spontaneous inflammation. Further, HYAL1 expression activated migration and promoted loss of DCs from the skin. We subsequently determined that induction of HYAL1 expression prior to topical antigen application resulted in a lack of an antigenic response due to the depletion of DCs from the skin. In contrast, induction of HYAL1 expression concurrent with antigen exposure accelerated allergic sensitization. Administration of HA tetrasaccharides, before or simultaneously with antigen application, recapitulated phenotypes observed in HYAL1-expressing animals, suggesting that the generation of small HA fragments, rather than the loss of large HA molecules, promotes DC migration and subsequent modification of allergic responses. Furthermore, mice lacking TLR4 did not exhibit HA-associated phenotypes, indicating that TLR4 mediates these responses. This study provides direct evidence that HA breakdown controls the capacity of the skin to present antigen. These events may influence DC function in injury or disease and have potential to be exploited therapeutically for modification of allergic responses.

Recombinant human hyaluronidase PH20 does not stimulate an acute inflammatory response and inhibits lipopolysaccharide-induced neutrophil recruitment in the air pouch model of inflammation

Hyaluronidase (Hyal) and low m.w. hyaluronan (LMW HA) fragments have been widely reported to stimulate the innate immune response. However, most hyaluronidases used were purified from animal tissues (e.g., bovine testis Hyal [BTH]), and contain endotoxin and other unrelated proteins. We tested a highly purified recombinant human Hyal (rHuPH20) and endotoxin-free HA fragments from M(r) 5,000 to 1,500,000 in the rodent air pouch model of inflammation to determine their potential for stimulation of the innate immune response. Exogenous LMW HA fragments (average M(r) 200,000) failed to induce either cytokine/chemokine production or neutrophil infiltration into the air pouch. Challenging the air pouch with LPS or BTH stimulated production of cytokines and chemokines but rHuPH20 did not, suggesting that neither PH20 nor generation of LMW HA fragments in situ stimulates cytokine and chemokine production. LPS and BTH also induced neutrophil infiltration into the air pouch, which was not observed with rHuPH20 treatment. Endotoxin-depleted BTH had much reduced proinflammatory activity, suggesting that the difference in inflammatory responses between rHuPH20 and BTH is likely due to endotoxin contaminants in BTH. When rHuPH20 was dosed with LPS, the induction of cytokines and chemokines was the same as LPS alone, but neutrophil infiltration was inhibited, likely by interrupting HA-CD44 interaction. Our results indicate that neither rHuPH20 nor its directly generated HA catabolites have inflammatory properties in the air pouch model, and rHuPH20 can instead inhibit some aspects of inflammation, such as neutrophil infiltration into the air pouch.

Transcriptional profiling of recall responses to Francisella live vaccine strain

Global gene expression profile changes were monitored in human peripheral blood mononuclear cells (PBMCs) after challenge with the live vaccine strain (LVS) of Francisella tularensis. Because these PBMCs were from individuals previously immunized with LVS, stimulating these cells with LVS should activate memory responses. The Ingenuity Pathway Analysis tool identified pathways, functions, and networks associated with this in vitro recall response, including novel pathways triggered by the memory response. Dendritic cell (DC) maturation was the most significant among the more than 25 relevant pathways discovered. Interleukin 15, granulocyte-macrophage colony-stimulating factor, and triggering receptor expressed on myeloid cells 1 signaling pathways were also significant. Pathway analysis indicated that Class 1 antigen presentation may not be optimal with LVS vaccination. The top three biological functions were antigen presentation, cell-mediated and humoral immune responses. Network analysis revealed that the top network associated with these functions had IFNγ and TNFα in central interactive positions. Our results suggest that DC maturation is a key factor in the recall responses and that more effective antigen processing and presentation is needed for cytotoxic T lymphocyte responses. Taken together, these considerations are critical for future tularemia vaccine development studies.

Polysaccharide-based nucleic acid nanoformulations

Therapeutic application of nucleic acids requires their encapsulation in nanosized carriers that enable safe and efficient intracellular delivery. Before the desired site of action is reached, drug-loaded nanoparticles (nanomedicines) encounter numerous extra- and intracellular barriers. Judicious nanocarrier design is highly needed to stimulate nucleic acid delivery across these barriers and maximize the therapeutic benefit. Natural polysaccharides are widely used for biomedical and pharmaceutical applications due to their inherent biocompatibility. At present, there is a growing interest in applying these biopolymers for the development of nanomedicines. This review highlights various polysaccharides and their derivatives, currently employed in the design of nucleic acid nanocarriers. In particular, recent progress made in polysaccharide-assisted nucleic acid delivery is summarized and the specific benefits that polysaccharides might offer to improve the delivery process are critically discussed.

Role of Hyaluronic Acid Treatment in the Prevention of Keloid Scarring

BACKGROUND

Keloids are benign dermal scars characterized by enhanced growth factor signaling, hyperproliferation activity and reduced extracellular matrix (ECM) deposition of hyaluronic acid. Our hypothesis is that high molecular weight HA can be used to replenish HA deposition in keloids thereby normalizing the keloid fibroblast phenotype.

METHODS

One normal (NF1) fibroblast culture and five keloid (KF1, KF2, KF3, KF4, KF5) fibroblast cultures were analyzed for changes in hyperproliferation, growth factor production and extracellular matrix deposition following 72 hour treatment with or without 10 μg/ml HA.

RESULTS

Proliferation activity decreased significantly in KF3 following HA treatment. Pro-collagen I expression in KF2 was decreased following HA treatment in association with changes in fiber arrangement to more parallel collagen bundles. In addition, HA demonstrated a downregulation on TGF-b1 growth factor expression in KF3 and KF4 and a decrease in active TGF-b1 release in KF2 and KF5 using ELISA.

CONCLUSION

Our data demonstrates that HA has the potential to normalize keloid fibroblast characteristic features such as hyperproliferation, growth factor production and ECM deposition depending on the specific genotype of the keloid fibroblast cell line. This study suggests that high molecular weight HA can be used to replenish HA deposition in keloid fibroblasts thereby decreasing fibrosis and ultimately decreasing keloid manifestation.

The hyaluronan receptor for endocytosis (HARE) activates NF-κB-mediated gene expression in response to 40-400-kDa, but not smaller or larger, hyaluronans

The hyaluronan (HA) receptor for endocytosis (HARE; Stabilin-2) binds and clears 14 different ligands, including HA and heparin, via clathrin-mediated endocytosis. HA binding to HARE stimulates ERK1/2 activation (Kyosseva, S. V., Harris, E. N., and Weigel, P. H. (2008) J. Biol. Chem. 283, 15047-15055). To assess a possible HA size dependence for signaling, we tested purified HA fractions of different weight-average molar mass and with narrow size distributions and Select-HA(TM) for stimulation of HARE-mediated gene expression using an NF-κB promoter-driven luciferase reporter system. Human HARE-mediated gene expression was stimulated in a dose-dependent manner with small HA (sHA) >40 kDa and intermediate HA (iHA) <400 kDa. The hyperbolic dose response saturated at 20-50 nM with an apparent K(m) ~10 nM, identical to the Kd for HA-HARE binding. Activation was not detected with oligomeric HA (oHA), sHA <40 kDa, iHA >400 kDa, or large HA (lHA). Similar responses occurred with rat HARE. Activation by sHA-iHA was blocked by excess nonsignaling sHA, iHA, or lHA, deletion of the HA-binding LINK domain, or HA-blocking antibody. Endogenous NF-κB activation also occurred in the absence of luciferase plasmids, as assessed by degradation of IκB-α. ERK1/2 activation was also HA size-dependent. The results show that HA-HARE interactions stimulate NF-κB-activated gene expression and that HARE senses a narrow size range of HA degradation products. We propose a model in which optimal length HA binds multiple HARE proteins to allow cytoplasmic domain interactions that stimulate intracellular signaling. This HARE signaling system during continuous HA clearance could monitor the homeostasis of tissue biomatrix turnover throughout the body.

Anti-inflammatory properties of phenolic lactones isolated from Caesalpinia paraguariensis stem bark

ETHNOPHARMACOLOGICAL RELEVANCE

Caesalpinia paraguariensis (D. Parodi) Burkart stem bark infusion (CPBI) is traditionally used in Argentina because their "vulnerary" properties.

AIM OF THE STUDY

CPBI was studied throughout bio-guided purification procedures conducted by in vitro biological assays in order to isolate the main bioactive compounds.

MATERIAL AND METHODS

Anti-inflammatory activity was assessed by enzyme inhibition assays of Hyaluronidase (Hyal) and inducible Nitric Oxide Synthase (iNOS). The antioxidant properties were evaluated by DPPH free radical scavenging assay, lipid peroxidation inhibition assay on erythrocyte membranes, and a cell-based assay that included the fluorescent probe (DCFH-DA) for indicating reactive oxygen species (ROS) generation. Bioactive compounds were purified by chromatographic methods and their structures elucidated using spectroscopic methods (ESI-MS and 1D/2D-(1)H/(13)C-NMR).

RESULTS

Four main bioactive compounds were isolated from CPBI: ellagic acid (1), 3-O-methylellagic acid (2), 3,3'-di-O-methylellagic acid (3) and 3,3'-di-O-methylellagic-4-β-D-xylopyranoside (4). These were bioactive at concentrations in which are present in CPBI, being compounds 2 and 3 the best enzyme inhibitors of Hyal and iNOS, reaching the 90% inhibitory concentration (IC90) values ranging from 2.8 to 16.4 μM, that are better than that of the positive controls, aspirin (IC90: no reached) and aminoguanidine (IC90: 20.2 μM) respectively. Compounds 2 and 3 were also better scavengers for lipoperoxides than butylated hydroxytoluene (BHT), reaching the 90% effective concentration (EC90) at 1.2-4.5 μg/ml, and for DPPH radical (2.5-7.3 μg/ml); moreover compounds were able to exert its scavenging action on intracellular ROS. Structural features relevant to the biological activities are discussed.

CONCLUSIONS

This work provides scientific validity to the popular usage of CPBI.

The role of hyaluronan and the extracellular matrix in islet inflammation and immune regulation

Type 1 diabetes (T1D) is a disease that in most individuals results from autoimmune attack of a single tissue type, the pancreatic islet. A fundamental, unanswered question in T1D pathogenesis is how the islet tissue environment influences immune regulation. This crosstalk is likely to be communicated through the extracellular matrix (ECM). Here, we review what is known about the ECM in insulitis and examine how the tissue environment is synchronized with immune regulation. In particular, we focus on the role of hyaluronan (HA) and its interactions with Foxp3+ regulatory T-cells (Treg). We propose that HA is a "keystone molecule" in the inflammatory milieu and that HA, together with its associated binding proteins and receptors, is an appropriate point of entry for investigations into how ECM influences immune regulation in the islet.

Spatio-temporal patterns of pancreatic cancer cells expressing CD44 isoforms on supported membranes displaying hyaluronic acid oligomers arrays

In this paper, we designed a quantitative model of biological membranes by the deposition of planar lipid membranes on solid substrates (called supported membranes), and immobilized biotinylated oligomers of hyaluronic acid (oligo-HA, 6–8 disaccharide units in length) to the membrane surface via neutravidin cross-linkers. By controlling the self-assembly of biotinylated lipid anchors, the mean distance between the oligo-HA molecules on the membrane could be controlled to nm accuracy. The adhesion and motility of pancreatic adenocarcinoma cells expressing different splice variants of the HA-binding cell surface receptor CD44 on these surfaces were investigated quantitatively. The combination of label-free, time-lapse imaging of living cells and statistical analysis suggests that the static morphology (global shape and cytoskeleton remodeling) of cells, their stochastic morphological dynamics, and the probability of directed motion reflect the metastatic behaviour of the cancer cells.