Differential effects between marimastat,a TNF-alpha converting enzyme inhibitor,and anti-TNF-alpha antibody on murine models for sepsis and arthritis

We investigated the effects of marimastat, an inhibitor of TNF-alpha converting enzyme and matrix metalloproteinases, and anti-TNF-alpha antibodies on a murine model for sepsis, and on arthritis in human TNF-alpha transgenic mice. Marimastat (25-200 mg/kg) inhibited lipopolysaccharide (LPS)-induced soluble TNF-alpha production in mice in a dose-dependent manner. At an oral dose of 200 mg/kg, marimastat almost completely inhibited LPS-induced soluble TNF-alpha production, but only slightly delayed LPS lethality. On the other hand, anti-TNF-alpha antibodies completely abolished LPS-induced morbidity. In addition, anti-TNF-alpha antibodies, but not marimastat (200 mg/kg/day), inhibited the development of arthritis in human TNF-alpha transgenic mice. These results suggest that cell surface TNF-alpha may be important in the pathogenesis of murine models for sepsis and arthritis.     

Towards bioreductively activated prodrugs: Fe(III) complexes of hydroxamic acids and the MMP inhibitor marimastat

Fe(III)-salen (N,N-bis(salicylidene)-ethane-1,2-diimine) complexes of simple hydroxamic acids and the MMP (matrix metalloproteinase) inhibitor marimastat have been evaluated as hypoxia activated drug carriers. The aceto- (aha), propion- (pha), benzohydroxamato (bha), and marimastat complexes were prepared and characterised by single crystal X-ray diffraction and electrochemical analysis. The hydroxamato ligands form a bidentate chelate to Fe(III) with the remaining octahedral coordination sites occupied by the tetradentate salen ligand. Bonding of the hydroxamato ligands is in the typical motif of the majority of Fe(III) complexes in the literature. The reduction potentials of the complexes are of the order of -1300 mV (vs ferrocene/ferrocenium) and show partial reversibility in the re-oxidation waveforms of the cyclic voltammetry scans. This suggests that the Fe-salen carrier system would provide a suitably redox inert framework yet would release the ligands at hypoxic tumour sites upon reduction to the more labile Fe(II) oxidation state. Furthermore, biological testing of the marimastat complex established that these carriers are stable in non-reducing biological environments and would serve to deliver MMP inhibitors to tumour sites intact.     

Advances and applications of de novo designed affinity ligands in proteomics

Affinity chromatography represents a promising technique for decoding the proteomics universe. While conventional affinity purification is being used in conjunction with two-dimensional electrophoresis (2D-PAGE) and mass spectrometry (MS) for the study of proteomes and subproteomes, scientists are still confronted with the need for specific and tailor-made affinity ligands to target desired groups and families of proteins. Evidence has shown that, in many situations, synthetic affinity ligands can circumvent inconveniences associated with the utilisation of biological ligands for the chromatography-based purification of biomolecules. This review will highlight the potential applications of affinity chromatography and synthetic de novo designed ligands as separation tools for proteomics.     

亲和层析技术在生物科学中的应用及发展

近几十年来,亲和层析技术发展十分迅速,广泛应用于生物分子(如结合蛋白、酶、抑制剂、抗原、抗体、激素、激素受体、糖蛋白、核酸及多糖类等)及组织(如细胞、细胞器、病毒等)的分离和纯化,是蛋白质组学研究中重要的技术之一.介绍了亲和层析的基本类型及配体合成的研究进展,概述了亲和层析技术在蛋白质组学以及在其他方面的应用和发展动态.     

Titanium dioxide as chemo-affinity chromatographic sorbent of biomolecular compounds--applications in acidic modification-specific proteomics

Characterization of the biomolecules involved in molecular processes occurring in biological systems such as the human cell remains central to biology, biotechnology, and medicine. One of the preferred methods of selectively purifying specific classes of biomolecules from complex biological matrices for further characterization is affinity chromatography, which relies on the specific interaction between an analyte in solution and a solid adsorbent. Titanium dioxide-based affinity chromatography has proven to be a versatile tool in enrichment of various compounds such as phosphorylated biomolecules due to its unique ion and ligand exchange properties and high stability towards pH and temperature. Recently, titanium dioxide chromatography was introduced in proteomics as a highly specific method for enriching phosphorylated peptides - a method, which has been widely adapted by the field of phosphoproteomics. Additional studies have shown the potential of this sorbent in purification of other acidic post-translational modified peptides, such as sialylated glycopeptides, thereby targeting the sialiome, defined as the content of sialic acid containing glycoproteins of a given cell, body fluid or tissue. The development of TiO(2)-based chromatographic strategies for separation of various biomolecules from its introduction for small molecules more than 20 years ago until recent proteomics applications today will be reviewed here.     

An in vitro model that can distinguish between effects on angiogenesis and on established vasculature: Actions of TNP-470, marimastat and the tubulin-binding agent Ang-510

In anti-cancer therapy, current investigations explore the possibility of two different strategies to target tumor vasculature; one aims at interfering with angiogenesis, the process involving the outgrowth of new blood vessels from pre-existing vessels, while the other directs at affecting the already established tumor vasculature. However, the majority of in vitro model systems currently available examine the process of angiogenesis, while the current focus in anti-vascular therapies moves towards exploring the benefit of targeting established vasculature as well. This urges the need for in vitro systems that are able to differentiate between the effects of compounds on angiogenesis as well as on established vasculature. To achieve this, we developed an in vitro model in which effects of compounds on different vascular targets can be studied specifically. Using this model, we examined the actions of the fumagillin derivate TNP-470, the MMP-inhibitor marimastat and the recently developed tubulin-binding agent Ang-510. We show that TNP-470 and marimastat solely inhibited angiogenesis, whereas Ang-510 potently inhibited angiogenesis and caused massive disruption of newly established vasculature. We show that the use of this in vitro model allows for specific and efficient screening of the effects of compounds on different vascular targets, which may facilitate the identification of agents with potential clinical benefit. The indicated differences in the mode of action between marimastat, TNP-470 and Ang-510 to target vasculature are illustrative for this approach.     

Preparation of ferric adsorbent paper and its interaction with phosphate-containing biomolecules.

A procedure for the synthesis of a selective adsorbent for phosphate-containing biomolecules is described. The sorbent is based on Whatman chromatography paper, which is activated with epichlorohydrine, followed by the coupling of iminodiacetic acid to the active surface of the sorbent. The immobilized complex-forming chelating groups are saturated with ferric ions. The synthesized adsorbent is a counterpart to Chelating Sepharose and makes it possible to extend the use of immobilized ferric chelating groups for analytical purposes. It displays a high affinity towards compounds containing free terminal phosphate groups (phosphopeptides, nucleotides). The results of the binding experiments are compared to the corresponding data obtained with Chelating Sepharose gels.     

Preparation of Ferric Adsorbent Paper and Its Interaction with Phosphate-Containing Biomolecules

Abstract

A procedure for the synthesis of a selective adsorbent for phosphate-containing biomolecules is described. The sorbent is based on Whatman chromatography paper, which is activated with epichlorohydrine, followed by the coupling of iminodiacetic acid to the active surface of the sorbent. The immobilized complex-forming chelating groups are saturated with ferric ions. The synthesized adsorbent is a counterpart to Chelating Sepharose and makes it possible to extend the use of immobilized ferric chelating groups for analytical purposes. It displays a high affinity towards compounds containing free terminal phosphate groups (phosphopeptides, nucleotides). The results of the binding experiments are compared to the corresponding data obtained with Chelating Sepharose gels.     

Affinity chromatography supports: a look at performance requirements.

Because of its high selectivity, affinity chromatography is a preferred tool in the downstream processing of high-value proteins and peptides of therapeutic interest. This review examines the affinity supports currently available, and investigates the performance characteristics and properties required of the support matrices for improved affinity-based supports for large-scale purification of biomolecules. Parameters for optimizing an affinity chromatographic process, and the advantages of affinity-based separation for scaled-up systems are highlighted.     

Boronic acids for affinity chromatography: spectral methods for determinations of ionization and diol-binding constants

Arylboronic acids attached to solid matrices have proved useful for the diol-specific chromatography of biomolecules and affinity purification of enzymes by exchangeable-ligand chromatography. The latter use has been limited by the intrinsic ionization constant (pKa approximately 9) of the most common commercial products. The synthesis of several arylboronic acids with ionization constants near neutrality are described, and the application of a new general, spectral-difference method for determining acid ionization constants and formation constants with fructose is developed. In particular 4-(N-methyl) carboxamido-benzeneboronic acid was found to have a pKa of 7.86 and a formation constant with D-fructose of 8600. It was stable toward acid or base hydrolysis. We suggest that 4-carboxybenzeneboronic acid might be useful for preparing matrices for enzyme affinity chromatography.     

Recent developments in downstream processing based on affinity interactions

Novel purification processes have been developed, based on the interaction between complementary biomolecules, to circumvent the difficulties encountered by conventional affinity chromatography. Depending upon the procedure used for isolating the ligand—binder complex, the process can be termed affinity cross-flow filtration, affinity partition or affinity precipitation. This review describes the developments and potentials of such purification techniques.     

The use of a proteinaceous “cushion” with a polystyrene‐binding peptide tag to control the orientation and function of a target peptide adsorbed to a hydrophilic polystyrene surface

In immobilizing target biomolecules on a solid surface, it is essential (i) to orient the target moiety in a preferred direction and (ii) to avoid unwanted interactions of the target moiety including with the solid surface. The preferred orientation of the target moiety can be achieved by genetic conjugation of an affinity peptide tag specific to the immobilization surface. Herein, we report on a strategy for reducing the extent of direct interaction between the target moiety and surface in the immobilization of hexahistidine peptide (6His) and green fluorescent protein (GFP) on a hydrophilic polystyrene (PS) surface: Ribonuclease HII from Thermococcus kodakaraensis (cHII) was genetically inserted as a “cushion” between the PS‐affinity peptide tag and target moiety. The insertion of a cushion protein resulted in a considerably stronger immobilization of target biomolecules compared to conjugation with only a PS affinity peptide tag, resulting in a substantially enhanced accessibility of the detection antibody to the target 6His peptide. The fluorescent intensity of the GFP moiety was decreased by approximately 30% as the result of fusion with cHII and the PS‐affinity peptide tag but was fully retained in the immobilization on the PS surface irrespective of the increased binding force. Furthermore, the fusion of cHII did not impair the stability of the target GFP moiety. Accordingly, the use of a proteinaceous cushion appears to be promising for the immobilization of functional biomolecules on a solid surface. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:527–534, 2016     

Side-by-Side Comparison of Commonly Used Biomolecules That Differ in Size and Affinity on Tumor Uptake and Internalization

The ability to use a systemically injected agent to image tumor is influenced by tumor characteristics such as permeability and vascularity, and the size, shape, and affinity of the imaging agent. In this study, six different imaging biomolecules, with or without specificity to tumor, were examined for tumor uptake and internalization at the whole body, ex-vivo tissue, and cellular levels: antibodies, antibody fragments (Fab), serum albumin, and streptavidin. The time of peak tumor uptake was dependent solely on the size of molecules, suggesting that molecular size is the major factor that influences tumor uptake by its effect on systemic clearance and diffusion into tumor. Affinity to tumor antigen failed to augment tumor uptake of Fab above non-specific accumulation, which suggests that Fab fragments of typical monoclonal antibodies may fall below an affinity threshold for use as molecular imaging agents. Despite abundant localization into the tumor, albumin and streptavidin were not found on cell surface or inside cells. By comparing biomolecules differing in size and affinity, our study highlights that while pharmacokinetics are a dominant factor in tumor uptake for biomolecules, affinity to tumor antigen is required for tumor binding and internalization.     

Surface modification for DNA and protein microarrays

Microarrays of biomolecules are emerging as powerful tools for genomics, proteomics, and clinical assays, since they make it possible to screen biologically important binding events in a parallel and high throughput fashion. Because the microarrays are fabricated on a solid support, coating of the surface and immobilization strategy of the biomolecules are major issues for successful microarray fabrication. This review deals with both DNA microarrays and protein microarrays, and focuses on the various modification approaches for the two-dimensional surface materials and three-dimensional ones. In addition, the immobilization strategies including adsorption, covalent attachment, physical entrapment, and affinity attachment of the biomolecules are summarized, and advantage and limitation of representative efforts are discussed.     

Negative chromatography: Progress,applications and future perspectives

In negative chromatography, the impurities bind on the adsorbent, and the product is allowed to flow through the chromatographic column. Negative chromatography is an alternative to positive chromatography under certain circumstances and has been used to purify various biomolecules. For this review, a detailed survey of the performance of reported studies on negative chromatography was conducted. The applications of negative chromatography in the capture and intermediate purification steps for biomolecules (e.g., plasmid DNA, antibodies, enzymes, hemoglobin, virus particles and cells) are reviewed. The negative chromatographic adsorbents adsorb the impurities through surface charge, hydrophobic interaction at specific sites on the surface, hydrophobic interaction, hydrogen bonding and functional groups. Examples of applications of negative chromatography according to the type of chromatography matrix used are summarized and discussed. In addition, the effects of operating conditions (initial protein concentration, buffer ions, pH and salt concentration) are discussed, and the criteria for choosing negative or positive chromatography are summarized. The literature survey showed that there will be future limitations and challenges ahead in implementation of negative chromatography. Possible solutions to the limitations and challenges of negative chromatography and future trends for developing negative chromatography are discussed.     

Small molecular ion adsorption on proteins and DNAs revealed by separation techniques

Ion binding is a term that assumes that the ion is included in the solvation sphere characterising the biomolecule. The binding forces are not clearly stated except for electrostatic attraction; weak forces (hydrogen bonds and Van der Waals forces) are likely involved. Many publications have dealt with ion binding to proteins and the consequences over the past 10 years, but only a few studies were performed using high-performance liquid chromatography (HPLC: ion exchange, reversed phase without the well-identified immobilised metal affinity chromatography) and capillary zone electrophoresis (CZE). This review focuses on the binding of proteins and DNAs mainly to the oxyanions (phosphate, borate, citrate) and amines used as buffers for both the HPLC eluent and the background electrolyte of CZE. Such specific ion adsorption on biomolecules is evidenced by physico-chemical characteristics such as the mobility or retention volume, closely associated with the net charge, which differ from the expected or experimental data obtained under the conditions of an indifferent electrolyte. It is shown that ion binding to proteins is a key parameter in the electrostatic repulsion between the free protein and a fouled membrane in the ultrafiltration separation of a protein mixture.     

Chemically modified diamond-like carbon (DLC) for protein enrichment and profiling by MALDI-MS

The development of new high throughput methods based on different materials with chemical modifications for protein profiling of complex mixtures leads towards biomarkers; used particularly for early diagnosis of a disease. In this work, diamond-like carbon (DLC) is developed and optimized for serum protein profiling by matrix-assisted laser/desorption ionization mass spectrometry (MALDI-MS). This study is carried out in connection with a material-based approach, termed as material-enhanced laser desorption ionization mass spectrometry. DLC is selected as carrier surface which provides large surface to volume ratio and offers high sensitivity. DLC has a dual role of working as MALDI target while acting as an interface for protein profiling by specifically binding peptides and proteins out of serum samples. Serum constituents are bound through immobilized metal ion affinity chromatography (IMAC) functionality, created through glycidyl methacrylate polymerization under ultraviolet light followed by further derivatization with iminodiacetic acid and copper ion loading. Scanning electron microscopy highlights the morphological characteristics of DLC surface. It could be demonstrated that IMAC functionalized DLC coatings represent a powerful material in trapping biomolecules for their further analysis by MALDI-MS resulting in improved sensitivity, specificity and capacity in comparison to other protein-profiling methods.     

A labeling, detection, and purification system based on 4-hydroxyazobenzene-2-carboxylic acid: an extension of the avidin-biotin system

We introduce a new nonradioactive, chromogenic label based on 4-hydroxyazobenzene-2-carboxylic acid (HABA), which is suitable for bioanalytical application, e.g., detection, localization, isolation, and purification. The HABA label is superior to other systems where it is difficult to separate labeled from unlabeled molecules or to determine the amount of label. HABA is readily detected spectroscopically by its absorption at 350 nm or by its interaction with avidin that results in a red shift to 500 nm. The HABA reagents described can be conjugated to a variety of functional groups on biomolecules and purified thereafter by affinity chromatography on an avidin column. The interaction of the HABAylated biomolecules with their corresponding targets is detected with high-affinity anti-HABA antibodies or with avidin. The nonradioactive, chromogenic HABA-based reagents form a homogeneous system that can complement or replace systems where facile quantification of the label is desired.