Potentiation and inhibition of bFGF binding by heparin: a model for regulation of cellular response

Integration of Zn2+, ATP, and bFGF to Nanodressing with Core-Shell Structure Fabricated by Emulsion Electrospinning for Wound Healing

Basic fibroblast growth factor (bFGF) plays an important role in active wound repair. However, the existing dosage forms in clinical applications are mainly sprays and freeze-dried powders, which are prone to inactivation and cannot achieve a controlled release. In this study, a bioactive wound dressing named bFGF-ATP-Zn/polycaprolactone (PCL) nanodressing with a "core-shell" structure was fabricated by emulsion electrospinning, enabling the sustained release of bFGF. Based on the coordination and electrostatic interactions among bFGF, ATP, and Zn2+, as well as their synergistic effect on promoting wound healing, a bFGF-ATP-Zn ternary combination system was prepared with higher cell proliferation activity and used as the water phase for emulsion electrospinning. The bFGF-ATP-Zn/PCL nanodressing demonstrated improved mechanical properties, sustained release of bFGF, cytocompatibility, and hemocompatibility. It increased the proliferation activity of human dermal fibroblasts (HDFs) and enhanced collagen secretion by 1.39 and 3.45 times, respectively, while reducing the hemolysis rate to 3.13%. The application of the bFGF-ATP-Zn/PCL nanodressing in mouse full-thickness skin defect repair showed its ability to accelerate wound healing and reduce wound scarring within 14 days. These results provide a research basis for the development and application of this bioactive wound dressing product.

The Effects of Heparan Sulfate Infusion on Endothelial and Organ Injury in a Rat Pneumosepsis Model

Septic shock is characterized by endothelial dysfunction, leading to tissue edema and organ failure. Heparan sulfate (HS) is essential for vascular barrier integrity, possibly via albumin as a carrier. We hypothesized that supplementing fluid resuscitation with HS would improve endothelial barrier function, thereby reducing organ edema and injury in a rat pneumosepsis model. Following intratracheal inoculation with Streptococcus pneumoniae, Sprague Dawley rats were randomized to resuscitation with a fixed volume of either Ringer's Lactate (RL, standard of care), RL supplemented with 7 mg/kg HS, 5% human albumin, or 5% human albumin supplemented with 7 mg/kg HS (n = 11 per group). Controls were sham inoculated animals. Five hours after the start of resuscitation, animals were sacrificed. To assess endothelial permeability, 70 kD FITC-labelled dextran was administered before sacrifice. Blood samples were taken to assess markers of endothelial and organ injury. Organs were harvested to quantify pulmonary FITC-dextran leakage, organ edema, and for histology. Inoculation resulted in sepsis, with increased lactate levels, pulmonary FITC-dextran leakage, pulmonary edema, and pulmonary histologic injury scores compared to healthy controls. RL supplemented with HS did not reduce median pulmonary FITC-dextran leakage compared to RL alone (95.1 CI [62.0-105.3] vs. 87.1 CI [68.9-139.3] µg/mL, p = 0.76). Similarly, albumin supplemented with HS did not reduce pulmonary FITC-dextran leakage compared to albumin (120.0 [93.8-141.2] vs. 116.2 [61.7 vs. 160.8] µg/mL, p = 0.86). No differences were found in organ injury between groups. Heparan sulfate, as an add-on therapy to RL or albumin resuscitation, did not reduce organ or endothelial injury in a rat pneumosepsis model. Higher doses of heparan sulfate may decrease organ and endothelial injury induced by shock.

Experimental study of a heparin-coated venous stent fabricated by atomic layer deposition

OBJECTIVE

To evaluate the safety and efficacy of heparin-coated venous stents in animals.

METHODS

We used atomic layer deposition technology to obtain a heparin coating with good stability and then prepared a heparin-coated venous stent based on this technology. The experimental stents were prepared according to the diameter of the rabbit inferior vena cava and were divided into Ni-Ti alloy stent group, Ni-Ti-Al₂O₃ stent group and Ni-Ti-Al₂O₃-Heparin stent group. 3 days, 7 days and 14 days after stent implantation, the materials were collected, and the three groups of stents were observed by hard tissue section pathology, immunohistochemistry and scanning electron microscope to observe the differences in vascular wall inflammation, thrombosis, lumen stenosis and vascular intima regeneration.

RESULT AND CONCLUSION

The experiment confirmed the safety of the heparin-coated stent in vivo. Compared with the control group, the experimental group showed a high degree of vascular endothelialization and an intact neointimal structure 14 days after implantation. The long-term safety and biological effects of heparin-coated venous stents in animals require further study.

The new general biological property of stem-like tumor cells Part I. Peculiarities of the process of the double-stranded DNA fragments internalization into stem-like tumor cells

Stem-like tumor cells of ascites carcinoma Krebs-2 and Epstein-Barr virus-induced B-lymphoma were shown to possess the innate capability of binding and internalizing the TAMRA-labeled double-stranded DNA (dsDNA) probe. The process of binding and internalizing is rather complicated and composed of the following successive stages: 1) initiating electrostatic interaction and contact of a negatively charged dsDNA molecule with a positively charged molecule(s) on the surface of a stem-like tumor cell; 2) binding of the dsDNA probe to a tumor stem cell surface protein(s) via the formation of a strong chemical/molecular bond; and 3) the very internalization of dsDNA into the cell. Binding of DNA to cell surface proteins is determined by the presence of heparin/polyanion-binding sites within the protein structure, which can be competitively blocked by heparin and/or dextran sulfate, wherein heparin blocks only the binding, while dextran sulfate abrogates both binding and internalization. The abrogation of internalization by dextran sulfate implies the role of scavenger receptors in this process. Cells were shown to uptake DNA in amounts constituting ∼0.008% of the haploid genome. Inhibitors of caveolae-dependent internalization abrogate the DNA uptake in Krebs-2 cells, and inhibitors of the clathrin/caveolar mechanism block the internalization in B-lymphoma cells. In the present report, it is shown for the first time that in contrast to the majority of committed tumor cells, stem-like tumor cells of Krebs-2 and B-lymphoma carry a general positive charge on their surface.

Heparin-mediated electrostatic immobilization of bFGF via functional polymer films for enhanced self-renewal of human neural stem cells

Preserving the self-renewal capability of undifferentiated human neural stem cells (hNSCs) is one of the crucial prerequisites for efficient hNSC-based regenerative medicine. Considering that basic fibroblast growth factor (bFGF) is one of the key contributing factors in maintaining the self-renewal property of hNSCs, the bioactivity and stability of bFGF in the hNSC culture should be regulated carefully. In this study, we developed a functional polymer film of poly(glycidyl methacrylate (GMA)-co-N,N-dimethylaminoethyl methacrylate (DMAEMA)) (coGD, or p(GMA-co-DMAEMA)) via initiated chemical vapor deposition (iCVD), which facilitated a stable, electrostatic adsorption of heparin and subsequent immobilization of bFGF. The bFGF-immobilized coGD surface substantially enhanced the proliferation rate and neurosphere forming ability of hNSCs compared to tissue culture plate (TCP). The expression of the stemness markers of hNSCs such as NESTIN and SOX-2 was also upregulated prominently on the coGD surface. Also, the hNSCs cultured on the coGD surface showed enhanced neurogenesis upon spontaneous differentiation. The immobilized bFGF on the coGD surface stimulated the expression of bFGF receptors and subsequently activated the mitogen-activated protein kinase (MAPK) pathway, attributed to the increase in self-renewal property of hNSCs. Our results indicate that the coGD surface allowed in situ heparin-mediated bFGF immobilization, which served as a robust platform to generate hNSC neurospheres with enhanced self-renewal and differentiation capabilities and thereby will prompt an advance in the field of therapeutics of neurodegenerative diseases.

Regulatory role of endogenous and exogenous fibroblast growth factor 1 in the cardiovascular system and related diseases

Fibroblast growth factor 1 (FGF1) has a critical regulatory role in the development of the cardiovascular system (CVS) and is strongly associated with the progression or treatment of cardiovascular diseases (CVDs). However, the regulatory mechanisms of FGF1 in CVS and CVDs have not yet been fully elucidated. Therefore, this review article summarized the existing literature reports on the role of FGF1 in CVS under physiological and pathological conditions. First, the expression and physiological functions of endogenous FGF1 is fully demonstrated. Then, we analyzed the role of exogenous FGF1 in normal CVS and related pathological processes. Specifically, the potential signaling pathways might be mediated by FGF1 in CVDs treatment is discussed in detail. In addition, the barriers and feasible solutions for the application of FGF1 are further analyzed. Finally, we highlight therapeutic considerations of FGF1 for CVDs in the future. Thus, this article may be as a reference to provide some ideas for the follow-up research.

Glycosaminoglycan-Protein Interactions and Their Roles in Human Disease

Glycosaminoglycans (GAGs) are a family of linear and negatively charged polysaccharides that exist ubiquitously on the human cell surface as well as in the extracellular matrix. GAGs interact with a wide range of proteins, including proteases, growth factors, cytokines, chemokines and adhesion molecules, enabling them to mediate many physiological processes, such as protein function, cellular adhesion and signaling. GAG-protein interactions participate in and intervene in a variety of human diseases, including cardiovascular disease, infectious disease, neurodegenerative diseases and tumors. The breakthrough in analytical tools and approaches during the last two decades has facilitated a greater understanding of the importance of GAG-protein interactions and their roles in human diseases. This review focuses on aspects of the molecular basis and mechanisms of GAG-protein interactions involved in human disease. The most recent advances in analytical tools, especially mass spectrometry-based GAG sequencing and binding motif characterization methods, are introduced. An update of selected families of GAG binding proteins is presented. Perspectives on development of novel therapeutics targeting specific GAG-protein interactions are also covered in this review.

Hybridization of a phospholipid polymer hydrogel with a natural extracellular matrix using active cell immobilization

Three-dimensional tissue organization is still an obstacle in the field of tissue engineering, which generally involves cell immobilization, proliferation, and organization. As an artificial extracellular matrix (ECM) for providing a suitable environment of cells to construct tissues, combination of cytocompatible polymer hydrogels and natural ECM produced by the immobilized cells was considered. In this research, we designed a spontaneously forming hydrogel system between two water-soluble polymers for the immobilization of cells. These polymers were poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate-co-p-vinylphenylboronic acid-co-N-succinimidyloxycarbonyl tetra(ethylene glycol)methacrylate) (PMBVS) and poly(vinyl alcohol) (PVA) to form a PMBVS/PVA hydrogel in a cell culture medium under mild conditions. Basic fibroblast growth factor (bFGF) was conjugated with PMBVS (PMBV-bFGF). To enhance the growth of the immobilized cells, mouse fibroblast L929 cells were immobilized in the PMBVS/PVA hydrogel and the PMBV-bFGF/PVA hydrogel, and their proliferation and secretion of the ECM under stimulation with bFGF was observed. The ECM infiltrated and replaced the hydrogel, resulting in the formation of a hybrid hydrogel with the ECM and laden cells.

A Review of Commercially Available Point-of-Care Devices to Concentrate Bone Marrow for the Treatment of Osteoarthritis and Focal Cartilage Lesions

OBJECTIVE

Mesenchymal stem cells (MSCs) are a promising cell-based therapy treatment option for several orthopedic indications. Because culture expansion of MSC is time and cost intensive, a bedside concentration of bone marrow (BM) aspirate is used as an alternative. Many commercial systems are available but the available literature and knowledge regarding these systems is limited. We compared different point-of-care devices that concentrate BM (BMC) by focusing on technical features and quality parameters to help surgeons make informed decisions while selecting the appropriate device.

METHODS

We compared published data on the BMC devices of Arteriocyte, Arthrex, Celling Biosciences, EmCyte, Exactech, ISTO Tech, Harvest Tech/Terumo BCT, and Zimmer/BIOMET regarding technical features (centrifugation speed/time, input/output volume, kit components, type of aspiration syringes, filter usage) and quality parameters of their final BMC product (hematocrit, concentration of platelets and total nucleated cells, concentration of MSC and connective tissue progenitor cells).

RESULTS

The systems differ significantly in their technical features and centrifugation parameters. Only the fully automated systems use universal kits, which allow processing different volumes of BM. Only the Arthrex system allows selection of final hematocrit. There was no standardized reporting method to describe biologic potency.

CONCLUSIONS

Based on the data obtained in this review, recommending a single device is not possible because the reported data could not be compared between devices. A standardized reporting method is needed for valid comparisons. Furthermore, clinical outcomes are required to establish the true efficacy of these systems. We are conducting additional studies for more careful comparison among the devices.

Molecular mechanisms of heparin-induced modulation of human interleukin 12 bioactivity

Human interleukin-12 (hIL-12) is a heparin-binding cytokine whose activity was previously shown to be enhanced by heparin and other sulfated glycosaminoglycans. The current study investigated the mechanisms by which heparin increases hIL-12 activity. Using multiple human cell types, including natural killer cells, an IL-12 indicator cell line, and primary peripheral blood mononuclear and T cells, along with bioactivity, flow cytometry, and isothermal titration calorimetry assays, we found that heparin-dependent modulation of hIL-12 function correlates with several of heparin's biophysical characteristics, including chain length, sulfation level, and concentration. Specifically, only heparin molecules longer than eight saccharide units enhanced hIL-12 activity. Furthermore, heparin molecules with three sulfate groups per disaccharide unit outperformed heparin molecules with one or two sulfate groups per disaccharide unit in terms of enhanced hIL-12 binding and activity. Heparin also significantly reduced the EC₅₀ value of hIL-12 by up to 11.8-fold, depending on the responding cell type. Cytokine-profiling analyses revealed that heparin affected the level, but not the type, of cytokines produced by lymphocytes in response to hIL-12. Interestingly, although murine IL-12 also binds heparin, heparin did not enhance its activity. Using the gathered data, we propose a model of hIL-12 stabilization in which heparin serves as a co-receptor enhancing the interaction between heterodimeric hIL-12 and its receptor subunits. The results of this study provide a foundation for further investigation of heparin's interactions with IL-12 family cytokines and for the use of heparin as an immunomodulatory agent.

Electron-ion reaction-based dissociation: A powerful ion activation method for the elucidation of natural product structures

The structural elucidation of natural products (NPs) remains a challenge due to their structurally diversities and unpredictable functionalities, motifs, and scaffolds. Tandem mass spectrometry (MS/MS) is an effective method that assists the full elucidation of complicated NP structures. Ion activation methods play a key role in determining the fragmentation pathways and the structural information obtained from MS/MS. Electron-ion reaction-based dissociation (ExD) methods, including electron capture dissociation (ECD), electron transfer dissociation (ETD), electron-induced dissociation (EID), and electron detachment dissociation (EDD), can induce the breakage of specific chemical bonds and the generation of distinct fragment ions. This review article provides an overview of the mechanisms, instrumentation, and typical applications related to ExD MS/MS in the structural elucidation of NPs, primarly including lipids, oligosaccharides, glycoconjugates, metabolites, and pharmaceutical drugs. This work aims to reveal the capacity and potential of ExD mass spectrometry in analyzing NPs and consequently helping the NP communities to utilize the modern capabilities of MS/MS in the discovery and evaluation of novel NPs.

Improved de novo sequencing of heparin/heparan sulfate oligosaccharides by propionylation of sites of sulfation

The structure of heparin and heparan sulfate (Hep/HS) oligosaccharides, as determined by the length and the pattern of sulfation, acetylation, and uronic acid epimerization, dictates their biological function through modulating interactions with protein targets. But fine structural determination is a very challenging task due to the lability of the sulfate modifications and difficulties in separating isomeric HS chains. Previously, we reported a strategy for chemical derivatization involving permethylation, desulfation, and trideuteroperacetylation, combined with standard reverse phase LC-MS/MS that enables the structural sequencing for heparin/HS oligosaccharides of sizes up to dodecasaccharide by positionally replacing all sulfates with more stable trideuteroacetyl groups, allowing for robust MS/MS sequencing. However, isomeric oligosaccharides that contain both N-sulfation and N-acetylation become isotopomers after labeling, differing only in the sites of deuteration. This prevents chromatographic separation of these different mixed domain sequences post-derivatization, and makes sequencing by MS/MS difficult due to co-fragmentation of the isotopomers leading to chimeric product ion spectra. In order to improve chromatographic separation of mixed domain oligosaccharides, we have introduced a propionylation step in place of trideuteroacetylation for labeling of sites of sulfation. HS standard disaccharides have been used to evaluate the efficiency of this improved chemical derivatization. The results show that we can quantitatively replace sulfation with propionyl groups with the same high efficiency as the previously reported trideuteroacetylation. After derivatization, we demonstrate the ability to chromatographically separate two mixed domain tetrasaccharide isomers differing solely by the order of N-sulfation and N-acetylation, allowing for full sequencing of each by MS/MS. These results represent a marked improvement in the ability of our previously reported derivatization strategy to analyze complex mixtures of Hep/HS oligosaccharides without a decrease in sensitivity.

Systems for localized release to mimic paracrine cell communication in vitro

Paracrine cell communication plays a pivotal role for signal exchange between proximal cells in vivo. However, this localized, gradient type release of mediators at very low concentrations (pg/ml), relevant during physiological and pathological processes, is rarely reflected within in vitro approaches. This review gives an overview on state-of-the-art approaches, which transfer the paracrine cell-to-cell communication into in vitro cell culture model setups. The traditional methods like trans-well assays and more advanced microfluidic approaches are included. The review focusses on systems for localized release, mostly based on microparticles, which tightly mimic the paracrine interaction between single cells in 3D microenvironments. Approaches based on single microparticles, with the main focus on affinity-controlled storage and release of cytokines, are reviewed and their importance for understanding paracrine communication is highlighted. Various methods to study the cytokine release and their advantages and disadvantages are discussed. Basic principles of the release characteristics, like diffusion mechanisms, are quantitatively described, including the formation of resulting gradients around the local sources. In vitro cell experiments using such localized microparticle release systems in approaches to increase understanding of stem cell behavior within their niches and regulation of wound healing are highlighted as examples of successful localized release systems for mimicking paracrine cell communication.

Osteoblastic heparan sulfate regulates osteoprotegerin function and bone mass

Bone remodeling is a highly coordinated process involving bone formation and resorption, and imbalance of this process results in osteoporosis. It has long been recognized that long-term heparin therapy often causes osteoporosis, suggesting that heparan sulfate (HS), the physiological counterpart of heparin, is somehow involved in bone mass regulation. The role of endogenous HS in adult bone, however, remains unclear. To determine the role of HS in bone homeostasis, we conditionally ablated Ext1, which encodes an essential glycosyltransferase for HS biosynthesis, in osteoblasts. Resultant conditional mutant mice developed severe osteopenia. Surprisingly, this phenotype is not due to impairment in bone formation but to enhancement of bone resorption. We show that osteoprotegerin (OPG), which is known as a soluble decoy receptor for RANKL, needs to be associated with the osteoblast surface in order to efficiently inhibit RANKL/RANK signaling and that HS serves as a cell surface binding partner for OPG in this context. We also show that bone mineral density is reduced in patients with multiple hereditary exostoses, a genetic bone disorder caused by heterozygous mutations of Ext1, suggesting that the mechanism revealed in this study may be relevant to low bone mass conditions in humans.

More than a biomarker: the systemic consequences of heparan sulfate fragments released during endothelial surface layer degradation (2017 Grover Conference Series)

Advances in tissue fixation and imaging techniques have yielded increasing appreciation for the glycosaminoglycan-rich endothelial glycocalyx and its in vivo manifestation, the endothelial surface layer (ESL). Pathological loss of the ESL during critical illness promotes local endothelial dysfunction and, consequently, organ injury. Glycosaminoglycan fragments, such as heparan sulfate, are released into the plasma of animals and humans after ESL degradation and have thus served as a biomarker of endothelial injury. The development of state-of-the-art glycomic techniques, however, has revealed that these circulating heparan sulfate fragments are capable of influencing growth factor and other signaling pathways distant to the site of ESL injury. This review summarizes the current state of knowledge concerning the local (i.e. endothelial injury) and systemic (i.e. para- or endocrine) consequences of ESL degradation and identifies opportunities for future, novel investigations.

A novel fibroblast growth factor-1 ligand with reduced heparin binding protects the heart against ischemia-reperfusion injury in the presence of heparin co-administration

AIMS

Fibroblast growth factor 1 (FGF1), a heparin/heparan sulfate-binding growth factor, is a potent cardioprotective agent against myocardial infarction (MI). The impact of heparin, the standard of care for MI patients entering the emergency room, on cardioprotective effects of FGF1 is unknown, however.

METHODS AND RESULTS

To address this, a rat model of MI was employed to compare cardioprotective potentials (lower infarct size and improve post-ischemic function) of native FGF1 and an engineered FGF1 (FGF1ΔHBS) with reduced heparin-binding affinity when given at the onset of reperfusion in the absence or presence of heparin. FGF1 and FGF1ΔHBS did not alter heparin's anticoagulant properties. Treatment with heparin alone or native FGF1 significantly reduced infarct size compared to saline (P < 0.05). Surprisingly, treatment with FGF1ΔHBS markedly lowered infarct size compared to FGF1 (P < 0.05). Both native and modified FGF1 restored contractile and relaxation function (P < 0.05 versus saline or heparin). Furthermore, FGF1ΔHBS had greater improvement in cardiac function compared to FGF1 (P < 0.05). Heparin negatively impacted the cardioprotective effects (infarct size, post-ischemic recovery of function) of FGF1 (P < 0.05) but not of FGF1ΔHBS. Heparin also reduced the biodistribution of FGF1, but not FGF1ΔHBS, to the left ventricle. FGF1 and FGF1ΔHBS bound and triggered FGFR1-induced downstream activation of ERK1/2 (P < 0.05); yet, heparin co-treatment decreased FGF1-produced ERK1/2 activation, but not that activated by FGF1ΔHBS.

CONCLUSION

These findings demonstrate that modification of the heparin-binding region of FGF1 significantly improves the cardioprotective efficacy, even in the presence of heparin, identifying a novel FGF ligand available for therapeutic use in ischemic heart disease.

Aqueous humour-induced lens epithelial cell proliferation requires FGF-signalling

The eye lens grows by systematic proliferation of its epithelial cells and their differentiation into fibre cells. The anterior aqueous humour regulates lens epithelial cell proliferation whereas posteriorly, the vitreous stimulates lens fibre differentiation. Vitreous-derived members of the fibroblast growth factor (FGF) family induce fibre differentiation, with added support for FGFs as putative regulators of aqueous-induced lens cell proliferation. To further characterize this, given FGFs' known affinity for proteoglycans, we compared the effect of proteoglycan sulphation in growth factor- and aqueous-induced lens cell proliferation. Disruption of proteoglycan sulphation in lens cells specifically impacted on aqueous- and FGF-induced MAPK/ERK1/2-signalling, but not on that induced by other mitogens such as PDGF; however, cell proliferation was reduced in all treatment groups, regardless of the mitogen. Overall, by disrupting proteoglycan activity, we further highlight the significant role of FGFs in aqueous-induced ERK1/2 phosphorylation leading to lens cell proliferation.

Negative Electron Transfer Dissociation Sequencing of Increasingly Sulfated Glycosaminoglycan Oligosaccharides on an Orbitrap Mass Spectrometer

The structural characterization of sulfated glycosaminoglycan (GAG) carbohydrates remains an important target for analytical chemists attributable to challenges introduced by the natural complexity of these mixtures and the defined need for molecular-level details to elucidate biological structure-function relationships. Tandem mass spectrometry has proven to be the most powerful technique for this purpose. Previously, electron detachment dissociation (EDD), in comparison to other methods of ion activation, has been shown to provide the largest number of useful cleavages for de novo sequencing of GAG oligosaccharides, but such experiments are restricted to Fourier transform ion cyclotron resonance mass spectrometers (FTICR-MS). Negative electron transfer dissociation (NETD) provides similar fragmentation results, and can be achieved on any mass spectrometry platform that is designed to accommodate ion-ion reactions. Here, we examine for the first time the effectiveness of NETD-Orbitrap mass spectrometry for the structural analysis of GAG oligosaccharides. Compounds ranging in size from tetrasaccharides to decasaccharides were dissociated by NETD, producing both glycosidic and cross-ring cleavages that enabled the location of sulfate modifications. The highly-sulfated, heparin-like synthetic GAG, ArixtraTM, was also successfully sequenced by NETD. In comparison to other efforts to sequence GAG chains without fully ionized sulfate constituents, the occurrence of sulfate loss peaks is minimized by judicious precursor ion selection. The results compare quite favorably to prior results with electron detachment dissociation (EDD). Significantly, the duty cycle of the NETD experiment is sufficiently short to make it an effective tool for on-line separations, presenting a straightforward path for selective, high-throughput analysis of GAG mixtures. Graphical Abstract ᅟ.

Radiolabeled 111In-FGF-2 Is Suitable for In Vitro/Ex Vivo Evaluations and In Vivo Imaging

Fibroblast growth factor-2 (FGF-2) is a potent modulator of cell growth and regulation, with improper FGF-2 signaling being involved in impaired responses to injury or even cancer. Therefore, the exploitation of FGF-2 as a therapeutic drives the prerequisite for effective insight into drug disposition kinetics. In this article, we present an ¹¹¹In-radiolabeled FGF-2 derivative for noninvasive imaging in small animals deploying single photon emission tomography (SPECT). ¹¹¹In-FGF-2 is equally well suitable for in vitro and ex vivo investigations as ¹²⁵I-FGF-2. Furthermore, ¹¹¹In-FGF-2 permits the performance of in vivo imaging, for example for the analysis of FGF-2 containing pharmaceutical formulations in developmental or preclinical stages. ¹¹¹In-FGF-2 had affinity for the low-molecular-weight heparin enoxaparin identical to that of unlabeled FGF-2 (K_d: 0.6 ± 0.07 μM and 0.33 ± 0.03 μM, respectively) as assessed by isothermal titration calorimetry. The binding of ¹¹¹In-FGF-2 to heparan sulfate proteoglycans (HPSGs) and the biological activity were comparable to those of unlabeled FGF-2, with EC₅₀ values of 12 ± 2 pM and 25 ± 6 pM, respectively. In vivo biodistribution in healthy nude mice indicated a predominant accumulation of ¹¹¹In-FGF-2 in filtering organs and minor uptake in the retina and the salivary and pituitary glands, which was confirmed by SPECT imaging. Therefore, ¹¹¹In-FGF-2 is a valid tracer for future noninvasive animal imaging of FGF-2 in pharmaceutical development.

Properties of internalization factors contributing to the uptake of extracellular DNA into tumor-initiating stem cells of mouse Krebs-2 cell line

Background

Previously, we demonstrated that poorly differentiated cells of various origins, including tumor-initiating stem cells present in the ascites form of mouse cancer cell line Krebs-2, are capable of naturally internalizing both linear double-stranded DNA and circular plasmid DNA.

Methods

The method of co-incubating Krebs-2 cells with extracellular plasmid DNA (pUC19) or TAMRA-5’-dUTP-labeled polymerase chain reaction (PCR) product was used. It was found that internalized plasmid DNA isolated from Krebs-2 can be transformed into competent Escherichia coli cells. Thus, the internalization processes taking place in the Krebs-2 cell subpopulation have been analyzed and compared, as assayed by E. coli colony formation assay (plasmid DNA) and cytofluorescence (TAMRA-DNA).

Results

We showed that extracellular DNA both in the form of plasmid DNA and a PCR product is internalized by the same subpopulation of Krebs-2 cells. We found that the saturation threshold for Krebs-2 ascites cells is 0.5 μg DNA/10⁶ cells. Supercoiled plasmid DNA, human high-molecular weight DNA, and 500 bp PCR fragments are internalized into the Krebs-2 tumor-initiating stem cells via distinct, non-competing internalization pathways. Under our experimental conditions, each cell may harbor 340–2600 copies of intact plasmid material, or up to 3.097 ± 0.044×10⁶ plasmid copies (intact or not), as detected by quantitative PCR.

Conclusion

The internalization dynamics of extracellular DNA, copy number of the plasmids taken up by the cells, and competition between different types of double-stranded DNA upon internalization into tumor-initiating stem cells of mouse ascites Krebs-2 have been comprehensively analyzed. Investigation of the extracellular DNA internalization into tumor-initiating stem cells is an important part of understanding their properties and possible destruction mechanisms. For example, a TAMRA-labeled DNA probe may serve as an instrument to develop a target for the therapy of cancer, aiming at elimination of tumor stem cells, as well as developing a straightforward test system for the quantification of poorly differentiated cells, including tumor-initiating stem cells, in the bulk tumor sample (biopsy or surgery specimen).

De Novo Sequencing of Complex Mixtures of Heparan Sulfate Oligosaccharides

Here, we describe the first sequencing method of a complex mixture of heparan sulfate tetrasaccharides by LC-MS/MS. Heparin and heparan sulfate (HS) are linear polysaccharides that are modified in a complex manner by N- and O-sulfation, N-acetylation, and epimerization of the uronic acid. Heparin and HS are involved in various essential cellular communication processes. The structural analysis of these glycosaminoglycans is challenging due to the lability of their sulfate groups, the high heterogeneity of modifications, and the epimerization of the uronic acids. While advances in liquid chromatography (LC) and mass spectrometry (MS) have enabled compositional profiling of HS oligosaccharide mixtures, online separation and detailed structural analysis of isomeric and epimeric HS mixtures has not been achieved. Here, we report the development and evaluation of a chemical derivatization and tandem mass spectrometry method that can separate and identify isomeric and epimeric structures from complex mixtures. A series of well-defined synthetic HS tetrasaccharides varying in sulfation patterns and uronic acid epimerization were analyzed by chemical derivatization and LC-MS/MS. These synthetic compounds made it possible to establish relationships between HS structure, chromatographic behavior and MS/MS fragmentation characteristics. Using the analytical characteristics determined through the analysis of the synthetic HS tetrasaccharide standards, an HS tetrasacharide mixture derived from natural sources was successfully sequenced. This method represents the first sequencing of complex mixtures of HS oligosaccharides, an essential milestone in the analysis of structure-function relationships of these carbohydrates.

The Antitumor Effect of Gekko Sulfated Glycopeptide by Inhibiting bFGF-Induced Lymphangiogenesis

Objective. To study the antilymphangiogenesis effect of Gekko Sulfated Glycopeptide (GSPP) on human lymphatic endothelial cells (hLECs). Methods. MTS was conducted to confirm the antiproliferation effect of GSPP on hLECs; flow cytometry was employed to detect hLECs cycle distribution; the antimigration effect of GSPP on hLECs was investigated by wound healing experiment and transwell experiment; tube formation assay was used to examine its inhibitory effect on the lymphangiogenesis; western blotting was conducted to detect the expression of extracellular signal-regulated kinase1/2 (Erk1/2) and p-Erk1/2 after GSPP and basic fibroblast growth factor (bFGF) treatment. Nude mice models were established to investigate the antitumor effect of GSPP in vivo. Decreased lymphangiogenesis caused by GSPP in vivo was verified by immunohistochemical staining. Results. In vitro, GSPP (10 μg/mL, 100 μg/mL) significantly inhibited bFGF-induced hLECs proliferation, migration, and tube-like structure formation (P < 0.05) and antagonized the phosphorylation activation of Erk1/2 induced by bFGF. In vivo, GSPP treatment (200 mg/kg/d) not only inhibited the growth of colon carcinoma, but also inhibited the tumor lymphangiogenesis. Conclusion. GSPP possesses the antitumor ability by inhibiting bFGF-inducing lymphangiogenesis in vitro and in vivo, which may further inhibit tumor lymphatic metastasis.

Interactions between nattokinase and heparin/GAGs

Nattokinase (NK) is a serine protease extracted from a traditional Japanese food called natto. Due to its strong fibrinolytic and thrombolytic activity, NK is regarded as a valuable dietary supplement or nutraceutical for the oral thrombolytic therapy. In addition, NK has been investigated for some other medical applications including treatment of hypertension, Alzheimer's disease, and vitreoretinal disorders. The most widely used clinical anticoagulants are heparin and low molecular weight heparins. The interactions between heparin and proteins modulate diverse patho-physiological processes and heparin modifies the activity of serine proteases. Indeed, heparin plays important roles in almost all of NK's potential therapeutically applications. The current report relies on surface plasmon resonance spectroscopy to examine NK interacting with heparin as well as other glycosaminoglycans (GAGs). These studies showed that NK is a heparin binding protein with an affinity of ~250 nM. Examination with differently sized heparin oligosaccharides indicated that the interaction between NK and heparin is chain-length dependent and the minimum size for heparin binding is a hexasaccharide. Studies using chemically modified heparin showed the 6-O-sulfo as well as the N-sulfo groups but not the 2-O-sulfo groups within heparin, are essential for heparin's interaction with NK. Other GAGs (including HS, DS, and CSE) displayed modest binding affinity to NK. NK also interfered with other heparin-protein interactions, including heparin's interaction with antithrombin and fibroblast growth factors.

A prospective comparison of 3 approved systems for autologous bone marrow concentration demonstrated nonequivalency in progenitor cell number and concentration

OBJECTIVES

To evaluate the efficacy of 3 commercially available systems: the Harvest SmartPReP 2 BMAC, Biomet BioCUE, and Arteriocyte Magellan systems. We compared the number and concentration of progenitor cells achieved both before and after centrifugation and the percentage of progenitor cells salvaged after centrifugation.

METHODS

Forty patients, mean age 47 ± 18 years (range: 18-92 years, 19 male/21 female) were prospectively consented for bilateral iliac crest aspiration. The first 20 aspirations compared the Harvest and Biomet systems, and based on those results, the second 20 compared the Harvest and Arteriocyte systems. One system was randomly assigned to each iliac crest. Each system's unique marrow acquisition process and centrifugation mechanism was followed. Samples for analysis were taken both immediately before the marrow was put into the centrifugation system (after acquisition), and after centrifugation. The number of progenitor cells in each sample was estimated by counting the connective tissue progenitors (CTPs).

RESULTS

The Harvest system achieved a significantly greater number and concentration of CTPs both before and after centrifugation when compared to the Biomet system. There was no difference in the percent yield of CTPs after centrifugation. There was no significant difference in the number and concentration of CTPs between the Harvest and Arteriocyte systems before centrifugation, but the Harvest system had a significantly greater number and concentration of CTPs after centrifugation. The Harvest system also had a significantly higher percent yield of CTPs after centrifugation compared with the Arteriocyte system.

CONCLUSIONS

The Harvest system resulted in a greater CTP number and concentration after centrifugation when compared with the Biomet and Arteriocyte systems and may thus provide increased osteogenic and chondrogenic capacity.

The effect of hibernation on the morphology and histochemistry of the intestine of the greater mouse-eared bat, Myotis myotis

Seasonal variations in morphometry and histochemistry of the intestine have been examined in the active and hibernating greater mouse-eared bat, Myotis myotis, using histological and histochemical techniques. The results of morphometric analyses indicated that hibernation affected the villus height, villus width, crypt depth and crypt width of the duodenum, jejunum and ileum. Histochemical analysis showed that goblet cells of the small and large intestine contain acidic and neutral mucosubstances. According to the results obtained with Alcian Blue (pH 5.8)/PAS staining, hyaluronic acid is dominant in the goblet cells of the small and large intestine during both the hibernation and active periods. Chondroitin sulfate and dermatan sulfate, which are sulfated GAGs, were dominant, and very little heparan sulfate, heparin and keratan sulfate were present. Moreover, sulfated glycoproteins were also detected in the goblet cells of the small intestine in the active animals. The present study demonstrates that hibernation altered the examined morphometric and histochemical parameters of the intestine.

Heparin and liver heparan sulfate can rescue hepatoma cells from topotecan action

Topotecan (TpT) is a major inhibitory compound of topoisomerase (topo) I that plays important roles in gene transcription and cell division. We have previously reported that heparin and heparan sulfate (HS) might be transported to the cell nucleus and they can interact with topoisomerase I. We hypothesized that heparin and HS might interfere with the action of TpT. To test this hypothesis we isolated topoisomerase I containing cell nuclear protein fractions from normal liver, liver cancer tissues, and hepatoma cell lines. The enzymatic activity of these extracts was measured in the presence of heparin, liver HS, and liver cancer HS. In addition, topo I activity, cell viability, and apoptosis of HepG2 and Hep3B cells were investigated after heparin and TpT treatments. Liver cancer HS inhibited topo I activity in vitro. Heparin treatment abrogated topo I enzyme activity in Hep3B cells, but not in HepG2 cells, where the basal activity was higher. Heparin protected the two hepatoma cell lines from TpT actions and decreased the rate of TpT induced S phase block and cell death. These results suggest that heparin and HS might interfere with the function of TpT in liver and liver cancer.

Deciphering the mechanism behind Fibroblast Growth Factor (FGF) induced biphasic signal-response profiles

BACKGROUND

The Fibroblast Growth Factor (FGF) pathway is driving various aspects of cellular responses in both normal and malignant cells. One interesting characteristic of this pathway is the biphasic nature of the cellular response to some FGF ligands like FGF2. Specifically, it has been shown that phenotypic behaviors controlled by FGF signaling, like migration and growth, reach maximal levels in response to intermediate concentrations, while high levels of FGF2 elicit weak responses. The mechanisms leading to the observed biphasic response remains unexplained.

RESULTS

A combination of experiments and computational modeling was used to understand the mechanism behind the observed biphasic signaling responses. FGF signaling involves a tertiary surface interaction that we captured with a computational model based on Ordinary Differential Equations (ODEs). It accounts for FGF2 binding to FGF receptors (FGFRs) and heparan sulfate glycosaminoglycans (HSGAGs), followed by receptor-phosphorylation, activation of the FRS2 adapter protein and the Ras-Raf signaling cascade. Quantitative protein assays were used to measure the dynamics of phosphorylated ERK (pERK) in response to a wide range of FGF2 ligand concentrations on a fine-grained time scale for the squamous cell lung cancer cell line H1703. We developed a novel approach combining Particle Swarm Optimization (PSO) and feature-based constraints in the objective function to calibrate the computational model to the experimental data. The model is validated using a series of extracellular and intracellular perturbation experiments. We demonstrate that in silico model predictions are in accordance with the observed in vitro results.

CONCLUSIONS

Using a combined approach of computational modeling and experiments we found that competition between binding of the ligand FGF2 to HSGAG and FGF receptor leads to the biphasic response. At low to intermediate concentrations of FGF2 there are sufficient free FGF receptors available for the FGF2-HSGAG complex to enable the formation of the trimeric signaling unit. At high ligand concentrations the ligand binding sites of the receptor become saturated and the trimeric signaling unit cannot be formed. This insight into the pathway is an important consideration for the pharmacological inhibition of this pathway.

Autocrine fibroblast growth factor 2-mediated interactions between human mesenchymal stem cells and the extracellular matrix under varying oxygen tension

Human mesenchymal stromal or stem cells (hMSCs) are being investigated for cell therapy in a wide range of diseases. MSCs are a potent source of trophic factors and actively remodel their immediate microenvironment through the secretion of bioactive factors in response to external stimuli such as oxygen tension. In this study, we examined the hypothesis that hypoxia influences hMSC properties in part through the regulation of extracellular milieu characterized by the extracellular matrix (ECM) matrices and the associated fibroblast growth factor-2 (FGF-2). The decellularized ECM matrices derived from hMSC culture under both hypoxic (e.g., 2% O(2)) and the standard culture (e.g., 20% O(2)) conditions have different binding capacities to the cell-secreted and exogenenous FGF-2. The reduced hMSC proliferation in the presence of FGF-2 inhibitor and the differential capacity of the decellularized ECM matrices in regulating hMSC osteogeneic and adipogenic differentiation suggest an important role of the endogenous FGF-2 in sustaining hMSC proliferation and regulating hMSC fate. Additionally, the combination of the ECM adhesion and hypoxic culture preserved hMSC viability under serum withdrawal. Together, the results suggest the synergistic effect of hypoxia and the ECM matrices in sustaining hMSC ex vivo expansion and preserving their multi-potentiality and viability under nutrient depletion. The results have important implication in optimizing hMSC expansion and delivery strategies to obtain hMSCs in sufficient quantity with required potency and to enhance survival and function upon transplantation.

Syndecan-1 and heparanase: potential markers for activity evaluation and differential diagnosis of Crohn's disease

BACKGROUND

Syndecan-1 (SDC1) and its endo-beta-D-glucuronidase heparanase (HPA) are implicated in the maintenance of intestinal barrier function, but their detailed functions in Crohn's disease (CD) are not fully investigated. The aim of this study was to determine alteration patterns of SDC1 and HPA and their potential roles in evaluating disease activity and differentiating CD from intestinal tuberculosis (ITB).

METHODS

Tissue and serum specimens were obtained from 89 patients, including 15 patients with functional bowel disorders, 18 active patients with ITB, and 56 patients with CD (remission = 19, active = 37). Basic clinical data were collected and routine blood tests were analyzed. SDC1 and HPA were measured by immunohistochemistry, enzyme-linked immunosorbent assay, reverse transcriptase polymerase chain reaction, and western blot. Colonic epithelial cells were incubated with recombinant HPA, tumor necrosis factor alpha (TNF-α), and mycobacterium tuberculosis culture filtrate protein to detect the alterations of SDC1 and HPA.

RESULTS

In the CD group, SDC1 was significantly decreased in mucosa and increased in serum, whereas HPA level in both were elevated. Such alterations were associated with clinicopathological features representing disease activity and injury severity and were not available in functional bowel disorder and ITB groups. Recombinant HPA incubation increased soluble SDC1 in culture supernatants (P = 2 × 10(-4)), and low-dose TNF-α effectively enhanced HPA's activity (P = 3 × 10(-6)). Exogenous TNF-α destroyed cellular SDC1 and raised HPA expressions dose dependently, whereas mycobacterium tuberculosis culture filtrate protein showed no effects.

CONCLUSIONS

Unique alterations of SDC1 and HPA are shown in both patients with CD and in vitro model. The results indicate SDC1 and HPA are potential markers for CD in evaluating its disease activity and differentiating it from ITB.

ELECTRON DETACHMENT DISSOCIATION OF SYNTHETIC HEPARAN SULFATE GLYCOSAMINOGLYCAN TETRASACCHARIDES VARYING IN DEGREE OF SULFATION AND HEXURONIC ACID STEREOCHEMISTRY

Glycosaminoglycan (GAG) carbohydrates provide a challenging analytical target for structural determination due to their polydisperse nature, non-template biosynthesis, and labile sulfate modifications. The resultant structures, although heterogeneous, contain domains which indicate a sulfation pattern or code that correlates to specific function. Mass spectrometry, in particular electron detachment dissociation Fourier transform ion cyclotron resonance (EDD FT-ICR MS), provides a highly sensitive platform for GAG structural analysis by providing cross-ring cleavages for sulfation location and product ions specific to hexuronic acid stereochemistry. To investigate the effect of sulfation pattern and variations in stereochemistry on EDD spectra, a series of synthetic heparan sulfate (HS) tetrasaccharides are examined. Whereas previous studies have focused on lowly sulfated compounds (0.5-1 sulfate groups per disaccharide), the current work extends the application of EDD to more highly sulfated tetrasaccharides (1-2 sulfate groups per disaccharide) and presents the first EDD of a tetrasaccharide containing a sulfated hexuronic acid. For these more highly sulfated HS oligomers, alternative strategies are shown to be effective for extracting full structural details. These strategies inlcude sodium cation replacement of protons, for determining the sites of sulfation, and desulfation of the oligosaccharides for the generation of product ions for assigning uronic acid stereochemistry.

Facilitated diffusion of VEGF165 through descemet's membrane with sucrose octasulfate

Vascular endothelial growth factor A (VEGF-A) is a promoter of neovascularization and thus a popular therapeutic target for diseases involving excessive growth of blood vessels. In this study, we explored the potential of the disaccharide sucrose octasulfate (SOS) to alter VEGF165 diffusion through Descemet's membrane. Descemet's membranes were isolated from bovine eyes and used as a barrier between two chambers of a diffusion apparatus to measure VEGF transport. Diffusion studies revealed a dramatic increase in VEGF165 transport in the presence of SOS, with little diffusion of VEGF165 across the membrane over a 10-h time course in the absence of SOS. Diffusion studies with VEGF121, a non-heparin binding variant of VEGF, showed robust diffusion with or without SOS. To determine a possible mechanism, we measured the ability of SOS to inhibit VEGF interactions with extracellular matrix (ECM), using cell-free and cell surface binding assays. Binding studies showed SOS had no effect on VEGF165 binding to either heparin-coated plates or endothelial cell surfaces at less than mg/ml concentrations. In contrast, we show that SOS inhibited VEGF165 binding to fibronectin in a dose dependent manner and dramatically accelerated the rate of release of VEGF165 from fibronectin. SOS also inhibited the binding of VEGF165 to fibronectin-rich ECM deposited by vascular smooth muscle cells. These results suggest that fibronectin-rich extracellular matrices serve as barriers to VEGF165 diffusion by providing a network of binding sites that can trap and sequester the protein. Since the content of Descemet's membrane is typical of many basement membranes it is possible that they serve throughout the body as formidable barriers to VEGF165 diffusion and tightly regulate its bioavailability and distribution within tissues.

Heparan sulfate proteoglycans regulate responses to oocyte paracrine signals in ovarian follicle morphogenesis

In the ovarian follicle, oocyte-secreted factors induce cumulus-specific genes and repress mural granulosa cell specific genes to establish these functionally distinct cell lineages. The mechanism establishing this precise morphogenic pattern of oocyte signaling within the follicle is unknown. The present study investigated a role for heparan sulphate proteoglycans (HSPG) as coreceptors mediating oocyte secreted factor signaling. In vitro maturation of cumulus oocyte complexes in the presence of exogenous heparin, which antagonizes HSPG signaling, prevented cumulus expansion and blocked the induction of cumulus-specific matrix genes, Has2 and Tnfaip6, whereas conversely, the mural granulosa-specific genes, Lhcgr and Cyp11a1, were strongly up-regulated. Heparin also blocked phosphorylation of SMAD2. Exogenous growth differentiation factor (GDF)-9 reversed these heparin effects; furthermore, GDF9 strongly bound to heparin sepharose. These observations indicate that heparin binds endogenous GDF9 and disrupts interaction with heparan sulphate proteoglycan coreceptor(s), important for GDF9 signaling. The expression of candidate HSPG coreceptors, Syndecan 1-4, Glypican 1-6, and Betaglycan, was examined. An ovulatory dose of human chorionic gonadotropin down-regulated Betaglycan in cumulus cells, and this regulation required GDF9 activity; conversely, Betaglycan was significantly increased in luteinizing mural granulosa cells. Human chorionic gonadotropin caused very strong induction of Syndecan 1 and Syndecan 4 in mural granulosa as well as cumulus cells. Glypican 1 was selectively induced in cumulus cells, and this expression appeared dependent on GDF9 action. These data suggest that HSPG play an essential role in GDF9 signaling and are involved in the patterning of oocyte signaling and cumulus cell function in the periovulatory follicle.

Hexuronic acid stereochemistry determination in chondroitin sulfate glycosaminoglycan oligosaccharides by electron detachment dissociation

Electron detachment dissociation (EDD) has previously provided stereo-specific product ions that allow for the assignment of the acidic C-5stereochemistry in heparan sulfate glycosaminoglycans (GAGs), but application of the same methodology to an epimer pair in the chondroitin sulfate glycoform class does not provide the same result. A series of experiments have been conducted in which glycosaminoglycan precursor ions are independently activated by electron detachment dissociation (EDD), electron induced dissociation (EID), and negative electron transfer dissociation (NETD) to assign the stereochemistry in chondroitin sulfate (CS) epimers and investigate the mechanisms for product ion formation during EDD in CS glycoforms. This approach allows for the assignment of electronic excitation products formed by EID and detachment products to radical pathways in NETD, both of which occur simultaneously during EDD. The uronic acid stereochemistry in electron detachment spectra produces intensity differences when assigned glycosidic and cross-ring cleavages are compared. The variations in the intensities of the doubly deprotonated (0,2)X(3) and Y(3) ions have been shown to be indicative of CS-A/DS composition during the CID of binary mixtures. These ions can provide insight into the uronic acid composition of binary mixtures in EDD, but the relative abundances, although reproducible, are low compared with those in a CID spectrum acquired on an ion trap. The application of principal component analysis (PCA) presents a multivariate approach to determining the uronic acid stereochemistry spectra of these GAGs by taking advantage of the reproducible peak distributions produced by electron detachment.

Regulation of autocrine fibroblast growth factor-2 signaling by perfusion flow in 3D human mesenchymal stem cell constructs

Perfusion bioreactor systems play a crucial role in mitigating nutrient limitation as well as providing biomechanical stimuli and redistributing regulatory macromolecules that influence human mesenchymal stem cells (hMSC) fate in three-dimensional (3D) scaffolds. As fibroblast growth factor-2 (FGF-2) is known to regulate hMSC phenotype, understanding the role of autocrine FGF-2 signaling in the 3D construct under the different perfusion flow provides important insight into an optimal bioreactor design. To investigate FGF-2 signaling inhibition in hMSC cultured in the porous poly(ethylene terephthalate) (PET) scaffolds perfused under two flow configurations, PD173074, an FGFR1 inhibitor, was added in growth media after 7 day of pre-culture and its impact on hMSC proliferation and clonogenicity during the subsequent 7 days of cultivation was analyzed. Compared with control constructs in growth media, the addition of PD173074 resulted in significant reduction in hMSC proliferation and colony formation in both constructs with a more dramatic reduction in the parallel flow constructs. The results demonstrate that autocrine FGF-2 plays a significant role in 3D scaffold and suggest modulation of the perfusion flow in the bioreactor as a strategy to influence autocrine actions and cell fate in the 3D scaffold.

HSULF-1 inhibits ERK and AKT signaling and decreases cell viability in vitro in human lung epithelial cells

BACKGROUND

Heparan sulfate proteoglycans (HSPGs) modulate the binding and activation of signaling pathways of specific growth factors, such as fibroblast growth factor-2 (FGF-2). Human endosulfatase 1 (HSULF-1) is an enzyme that selectively removes 6-O sulfate groups from HS side chains and alter their level and pattern of sulfation and thus biological activity. It is known that HSULF-1 is expressed at low levels in some cancer cell lines and its enhanced expression can inhibit cancer cell growth or induce apoptosis, but the mechanism(s) involved has not been identified.

METHODS

HSULF-1 mRNA expression was assessed in five normal cells (primary human lung alveolar type 2 (hAT2) cells, adult lung fibroblasts (16Lu), fetal lung fibroblasts (HFL), human bronchial epithelial cells (HBE), and primary human lung fibroblasts (HLF)) and five lung cancer cell lines (A549, H292, H1975, H661, and H1703) using quantitative real time polymerase chain reaction (qRT-PCR). H292 and hAT2 cells over-expressing HSULF-1 were analyzed for cell viability, apoptosis, and ERK/Akt signaling, by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, TUNEL (Terminal deoxynucleotidyl transferase dUTP nick end labeling) assay, and Western Blot, respectively. Apoptosis pathway activation was confirmed by PCR array in hAT2, H292, and A549 cells.

RESULTS

HSULF-1 was expressed at a significantly lower level in epithelial cancer cell lines compared to normal cells. Infection with recombinant adenovirus for HSULF-1 over-expression resulted in decreased cell viability in H292 cells, but not in normal hAT2 cells. HSULF-1 over-expression induced apoptosis in H292 cells, but not in hAT2 cells. In addition, apoptosis pathways were activated in both H292 and A549 cells, but not in hAT2 cells. HSULF-1 over-expression reduced ERK and Akt signaling activation in H292 cells, which further demonstrated its inhibitory effects on signaling related to proliferation.

CONCLUSIONS

These results indicate that HSULF-1 is expressed at lower levels in H292 lung cancer cells than in normal human alveolar cells and that its over-expression reduced cell viability in H292 cells by inducing apoptotic pathways, at least in part by inhibiting ERK/Akt signaling. We hypothesize that HSULF-1 plays important roles in cancer cells and functions to modify cell signaling, inhibit cancer proliferation, and promote cancer cell death.

Bio-functionalization of ligand-free upconverting lanthanide doped nanoparticles for bio-imaging and cell targeting

We report on the functionalization of ligand-free NaGdF(4):Er(3+), Yb(3+) upconverting nanoparticles with heparin and basic fibroblast growth factor (bFGF). These upconverting nanoparticles are used to obtain high-contrast images of HeLa cells. These images reveal that the heparin-bFGF functionalized nanoparticles show specific binding to the cell membrane.

Heparosan-derived heparan sulfate/heparin-like compounds: one kind of potential therapeutic agents

Heparan sulfate (HS) is a highly sulfated glycosaminoglycan and exists in all animal tissues. HS and heparin are very similar, except that heparin has higher level of sulfation and higher content of iduronic acid. Despite the fact that it is a century-old drug, heparin remains as a top choice for treating thrombotic disorders. Pharmaceutical heparin is derived from porcine intestine or bovine lung via a long supply chain. This supply chain is vulnerable to the contamination of animal pathogens. Therefore, new methods for manufacturing heparin or heparin-like substances devoid of animal tissues have been explored by many researchers, among which, modifications of heparosan, the capsular polysaccharide of Escherichia coli K5 strain, is one of the promising approaches. Heparosan has a structure similar to unmodified backbone of natural HS and heparin. It is feasible to obtain HS or heparin derivatives by modifying heparosan with chemical or enzymatic methods. These derivatives display different biological activities, such as anticoagulant, anti-inflammatory, anticancer, and antiviral activities. This review focuses on the recent studies of synthesis, activity, and structure-activity relationship of HS/heparin-like derivatives prepared from heparosan.

Association of the -33C/G OSF-2 and the 140A/G LF gene polymorphisms with the risk of chronic rhinosinusitis with nasal polyps in a Polish population

Nasal polyps are strongly associated with a risk of chronic rhinosinusitis development as well as other obstruction including asthma and allergy. The following study tested the association of the 140A/G polymorphism of lactoferine (LF) encoding gene and the -33C/G polymorphism of osteoblast-specific factor-2 (OSF-2) encoding gene with a risk of chronic rhinosinusitis with nasal polyps in a Polish population. One hundred ninety five patients of chronic rhinosinusitis with nasal polyps as well as 200 sex, age and ethnicity matched control subjects without chronic sinusitis and nasal polyps were enrolled in this study. Among the group of patients 63 subjects were diagnosed with allergy and 65 subjects with asthma, respectively. DNA was isolated from peripheral blood lymphocytes of patients as well as controls and gene polymorphisms were analyzed by restriction fragments length polymorphism polymerase chain reaction (RFLP-PCR). We reported that the 140A/G LF (OR 4.78; 95% CI 3.07-7.24), the -33C/G OSF-2 OR 3.48; 95% CI 2.19-5.52) and the -33G/G OSF-2 (OR 16.45; 95% CI 6.71-40.30) genotypes were associated with an increased risk of chronic rhinosinusitis with nasal polyps among analyzed group of patients. Moreover, the group of patients without allergy or asthma indicated the association of the -33C/G (OR 3.72; 95% CI 2.24-6.19 and OR 15.11; 95% CI 5.91-38.6) and -33G/G (OR 3.73; 95% CI 2.24-6.19 and OR 14.07; 95% CI 5.47-36.16) genotypes of the OSF-2 as wells as 140A/G (OR 3.89; 95% CI 2.40-6.31 and OR 3.62; 95% CI 2.45-5.34) genotype of OSF-2 with an increased risk of chronic rhinosinusitis with nasal polyps. Finally, it was also found that the selected group of patients with allergy or asthma indicated a very strong association of the -33C/G (OR 2.40; 95% CI 1.23-4.69 and OR 2.40; 95% CI 1.23-4.69, respectively) and -33G/G (OR 16.01; 95% CI 5.77-44.41 and OR 17.90; 95% CI 6.53-49.05, respectively) genotypes of the OSF-2 as wells as 140A/G (OR 3.22; 95% CI 1.74-6.11 and OR 3.25; 95% CI 1.75-6.04, respectively) genotypes with an increased risk of chronic rhinosinusitis with nasal polyps. Thus, our results suggest that LF and OSF-2 gene polymorphisms may have deep impact on the risk of rhinosinusitis nasal polyps' formation which may also depend on asthma or allergy. Our results showed that the 140A/G polymorphism of LF gene and the -33C/G polymorphism of the OSF-2 gene may be associated with the risk of chronic rhinosinusitis with nasal polyps in a Polish population.

Perfusion regulation of hMSC microenvironment and osteogenic differentiation in 3D scaffold

The combination of hMSCs with 3D scaffolds has become an important approach to creating functional bone constructs. Bioreactors are important tools to mitigate mass transfer limitations and to provide controlled physiochemical and biomechanical environments for the 3D bone construct development. Media flow in the bioreactor systems is generally controlled either parallel or transverse with respect to the 3D construct, creating different cellular and biomechanical microenvironments in the 3D constructs. In this study, a custom designed modular perfusion bioreactor system was operated under either the parallel or transverse flow. The influence of the flow patterns on the characteristics of the hMSCs' cellular microenvironment and subsequent construct development was investigated. The parallel flow configuration retained ECM proteins and mitogenic growth factors within the scaffold, effectively preserving hMSC progenicity and proliferation potential (e.g., CFU-F, proliferation, and OCT-4), whereas the transverse flow induced hMSC osteogenic differentiation with higher ALP activity and calcium deposition and up-regulation of osteogenic bone markers (e.g., BMP-2, ALP, RUNX2, OSX, and OC). These results demonstrate the regulatory role of the macroscopic flow on the cellular microenvironment of the 3D hMSC construct, and suggest configuring media flow as a strategy for directing hMSC fate and 3D bone construct development in the perfusion bioreactor.

Lactoferrin inhibits the growth of nasal polyp fibroblasts

The aim of this study was to evaluate the effects of lactoferrin (LF) on the growth of fibroblasts derived from nasal polyps. We showed that the proliferation of fibroblasts was inhibited in a dose-dependent manner by both native and recombinant LF. The greatest inhibition of proliferation was caused by human milk-derived, iron-saturated LF. The inhibition of fibroblast proliferation was not species specific because bovine LF also was active. The interaction between LFs and a putative cell receptor did not depend on the sugar composition of the glycan moiety of the LF molecule because lactoferrins of different origins were active and the addition of monosaccharides to the cultures did not block proliferation. However, the treatment of fibroblasts with sodium chlorate (an inhibitor of glycosaminoglycan sulfation) or the addition of heparin abolished the inhibitory effect of LF, suggesting that LF binds heparan sulfate-containing proteoglycans. The significance of LF in nasal excretions in controlling polyp formation is discussed.

Predifferentiated brain-derived adult human progenitor cells migrate toward ischemia after transplantation to the adult rat brain

BACKGROUND

The adult human brain contains neural stem/progenitor cells (AHNPCs) that can survive transplantation into the adult rat brain, migrate toward a lesion, and display limited neuronal differentiation in vivo.

OBJECTIVE

To investigate the effect of manipulating AHNPCs before grafting by predifferentiation, ie, initiating neuronal differentiation before transplantation, and to determine whether this cell priming would affect their ability to migrate in vivo.

METHODS

AHNPCs were prepared from temporal lobe resections for epilepsy. Seven days after global brain ischemia, predifferentiated AHNPCs (exposed to basic fibroblast growth factor, heparin, and laminin) were transplanted to the left hippocampus. Four and 10 weeks after transplantation, brain sections were analyzed by immunohistochemistry.

RESULTS

Transplanted primed cells expressed committed neuronal markers at a much earlier stage compared with nonprimed AHNPCs and were found colabeled with human markers within the damaged CA1 region 4 weeks after grafting. Furthermore, predifferentiated AHNPCs migrated preferentially into an ischemic lesion, similar to their undifferentiated counterparts. The chemoattractant effect from the expression of stromal cell-derived factor-1α (SDF-1α) in ischemic CA1 on AHNPCs expressing CXC chemokine receptor 4 (CXCR4) may explain this preference in migration in vivo.

CONCLUSION

The plasticity of neural progenitors derived from the adult human brain may be greater than previously assumed in that manipulation before grafting may influence the phenotypes seen in vivo. The SDF-1α-CXCR4 axis is involved in the targeted migration toward an ischemic lesion in the adult rat brain, similar to previous reports on endogenous progenitors in rats and grafted fetal human neural progenitors.

Ultraviolet photodissociation of chromophore-labeled oligosaccharides via reductive amination and hydrazide conjugation

The fragmentation patterns of hydrazide-conjugated and reductively aminated oligosaccharides, including lacto-N-fucopentaoses and lacto-N-difucohexaoses, produced on collisionally induced dissociation (CID) and ultraviolet photodissociation (UVPD) in a quadrupole ion trap are presented. The two derivatization methods generate different cross-ring cleavages on UVPD and CID. UVPD of hydrazide-conjugated oligosaccharides yield predominant (2, 4)A-type cross-ring cleavage ions. In contrast, UVPD of aminated oligosaccharides results mainly in (0, 1)A-type ions. Moreover, more extensive dual-cleavage pathways (i.e. internal fragment ions) were observed on UVPD.

Multivariate analysis of electron detachment dissociation and infrared multiphoton dissociation mass spectra of heparan sulfate tetrasaccharides differing only in hexuronic acid stereochemistry

The structural characterization of glycosaminoglycan (GAG) carbohydrates by mass spectrometry has been a long-standing analytical challenge due to the inherent heterogeneity of these biomolecules, specifically polydispersity, variability in sulfation, and hexuronic acid stereochemistry. Recent advances in tandem mass spectrometry methods employing threshold and electron-based ion activation have resulted in the ability to determine the location of the labile sulfate modification as well as assign the stereochemistry of hexuronic acid residues. To facilitate the analysis of complex electron detachment dissociation (EDD) spectra, principal component analysis (PCA) is employed to differentiate the hexuronic acid stereochemistry of four synthetic GAG epimers whose EDD spectra are nearly identical upon visual inspection. For comparison, PCA is also applied to infrared multiphoton dissociation spectra (IRMPD) of the examined epimers. To assess the applicability of multivariate methods in GAG mixture analysis, PCA is utilized to identify the relative content of two epimers in a binary mixture.

Temporal changes in expression of FoxA1 and Wnt7A in isolated adult human alveolar epithelial cells enhanced by heparin

Pre- and postnatal developmental studies of the lung have provided compelling evidence demonstrating multiple factors that orchestrate alveolar epithelial cell differentiation. The extent to which reactivation of certain developmental pathways in the adult might influence the course of differentiation of alveolar type 2 cells (AT2) into AT1 cells is not known. In this study, we examined selected members of the forkhead (Fox) family of transcription factors and the Wnt (wingless) family of signaling proteins for expression during human alveolar cell differentiation in vitro and determined their potential responses to sulfated components of extracellular matrix (ECM), like those shed from cell surfaces or found in basement membrane and modeled by heparin. Isolated adult human AT2 cells cultured over a 9-day period were used to define the temporal profile of expression of targeted factors during spontaneous differentiation to AT1-like cells. FoxA1 protein was upregulated at early to intermediate time points, where it was strongly elevated by heparin. Gene expression of wnt7A increased dramatically beginning on day 3 and was enhanced even further on days 7 and 9 by heparin, whereas protein expression appeared at days 7 and 9. These temporal changes of expression suggest that sulfated ECMs may act to enhance the increase in FoxA1 at the critical juncture when AT2 cells commence the differentiation process to AT1 cells, in addition to enhancing the increase in wnt7A when the AT1 cell phenotype stabilizes. Collectively, these factors may act to modulate differentiation in the adult human pulmonary alveolus.