Showing papers on "Serum albumin published in 2003"
TL;DR: In this paper, a low molecular weight (LMW) serum proteome was extracted from serum and analyzed using microcapillary reversed-phase liquid chromatography coupled with electrospray ionization tandem mass spectrometry.
830 citations
TL;DR: These results affirm the hypothesis that the major histocompatibility complex–related Fc receptor protects albumin from degradation just as it does IgG, prolonging the half-lives of both.
Abstract: The inverse relationship between serum albumin concentration and its half-life suggested to early workers that albumin would be protected from a catabolic fate by a receptor-mediated mechanism much like that proposed for IgG. We show here that albumin binds FcRn in a pH dependent fashion, that the lifespan of albumin is shortened in FcRn-deficient mice, and that the plasma albumin concentration of FcRn-deficient mice is less than half that of wild-type mice. These results affirm the hypothesis that the major histocompatibility complex-related Fc receptor protects albumin from degradation just as it does IgG, prolonging the half-lives of both.
576 citations
TL;DR: The structure of the HSA-hemin-myristate complex (PDB ID 1o9x) reveals the key polar and hydrophobic interactions that determine the hemin-binding specificity of HSA.
Abstract: Human serum albumin (HSA) is an abundant plasma protein that binds a wide variety of hydrophobic ligands including fatty acids, bilirubin, thyroxine and hemin. Although HSA-heme complexes do not bind oxygen reversibly, it may be possible to develop modified HSA proteins or heme groups that will confer this ability on the complex. We present here the crystal structure of a ternary HSA-hemin-myristate complex, formed at a 1:1:4 molar ratio, that contains a single hemin group bound to subdomain IB and myristate bound at six sites. The complex displays a conformation that is intermediate between defatted HSA and HSA-fatty acid complexes; this is likely to be due to low myristate occupancy in the fatty acid binding sites that drive the conformational change. The hemin group is bound within a narrow D-shaped hydrophobic cavity which usually accommodates fatty acid; the hemin propionate groups are coordinated by a triad of basic residues at the pocket entrance. The iron atom in the centre of the hemin is coordinated by Tyr161. The structure of the HSA-hemin-myristate complex (PDB ID 1o9x) reveals the key polar and hydrophobic interactions that determine the hemin-binding specificity of HSA. The details of the hemin-binding environment of HSA provide a structural foundation for efforts to modify the protein and/or the heme molecule in order to engineer complexes that have favourable oxygen-binding properties.
458 citations
TL;DR: PFOA binding to rat and human plasma proteins was investigated and it was found that greater than 90% of PFOA would be bound to serum albumin in bothRat and human blood.
Abstract: Perfluorooctanoic acid (PFOA) is a commercially important organic fluorochemical and is considered to have a long half-life in human blood. In this paper, PFOA binding to rat and human plasma proteins was investigated. On the basis of results from size-exclusion chromatography and ligand blotting, most PFOA was in protein-bound form in male and female rat plasma, and the primary PFOA binding protein in plasma was serum albumin. PFOA binding to rat serum albumin (RSA) in the gas phase was observed by electrospray ionization MS. 19F NMR experiments revealed that binding to RSA caused peak broadening and chemical shift changes of PFOA resonances, and on the basis of this observation, the dissociation constant was determined to be ∼0.3 mM. The dissociation constants for PFOA binding to RSA and human serum albumin (HSA) and the numbers of PFOA binding sites on RSA and HSA were also determined by a separation method using microdesalting columns. No significant difference was found between PFOA binding to RSA an...
339 citations
TL;DR: QD/SSA complex can be used as a long-life and highly photostable endosome marker in biological buffers and is detectable, at least, 30 times as long as that of fluorescein-labeled dextran involved in endosomes.
325 citations
TL;DR: In conclusion, albumin is a strong stimulus for tubular IL-8 expression, which occurs via NF-kappaB-dependent pathways through PKC activation and ROS generation.
Abstract: Renal tubulointerstitial injury is characterized by inflammatory cell infiltrate; however, the stimuli for leukocyte recruitment are not fully understood. IL-8 is a potent chemokine produced by proximal tubular epithelial cells (PTECs). Whether nephrotic proteins stimulate tubular IL-8 expression remains unknown. Acute exposure of human PTECs to albumin induced IL-8 gene and protein expression time- and dose-dependently. Apical albumin predominantly stimulated basolateral IL-8 secretion. Electrophoretic mobility shift assay demonstrated nuclear translocation of NF-κB, and the p65/p50 subunits were activated. NF-κB activation and IL-8 secretion were attenuated by the NF-κB inhibitors pyrrolidine dithiocarbamate and cell-permeable peptide. Albumin upregulated intracellular reactive oxygen species (ROS) generation, while exogenous H2O2 stimulated NF-κB translocation and IL-8 secretion. Albumin-induced ROS generation, NF-κB activation, and IL-8 secretion were endocytosis- and PKC-dependent as these downstream events were abrogated by the PI3K inhibitors LY294002 and wortmannin, and the PKC inhibitors GF109203X and staurosporin, respectively. In vivo, IL-8 mRNA expression was localized by in situ hybridization to the proximal tubules in nephrotic kidney tissues. The intensity of IL-8 immunostaining was higher in nephrotic than non-nephrotic subjects. In conclusion, albumin is a strong stimulus for tubular IL-8 expression, which occurs via NF-κB–dependent pathways through PKC activation and ROS generation.
267 citations
TL;DR: Evidence is provided that human "hematopoietic" stem/progenitor cell populations have the capacity to respond to the injured liver microenvironment by inducing albumin expression.
244 citations
TL;DR: Using monoclonal antibodies against human serum albumin (HSA) to develop an immunoaffinity resin that is effective in the removal of both full-length HSA and many of the HSA fragments present in serum shows markedly better performance than dye-based resins in terms of both the efficiency and specificity of albumin removal.
222 citations
TL;DR: The majority of low molecular mass biomarkers exist bound to carrier proteins, and the pattern of LMM biomarkers bound specifically to albumin is distinct from those bound to non-albumin carriers.
Abstract: Mass spectroscopic analysis of the low molecular mass (LMM) range of the serum/plasma proteome is a rapidly emerging frontier for biomarker discovery. This study examined the proportion of LMM biomarkers, which are bound to circulating carrier proteins. Mass spectroscopic analysis of human serum following molecular mass fractionation, demonstrated that the majority of LMM biomarkers exist bound to carrier proteins. Moreover, the pattern of LMM biomarkers bound specifically to albumin is distinct from those bound to non-albumin carriers. Prominent SELDI-TOF ionic species (m/z 6631.7043) identified to correlate with the presence of ovarian cancer were amplified by albumin capture. Several insights emerged: a) Accumulation of LMM biomarkers on circulating carrier proteins greatly amplifies the total serum/plasma concentration of the measurable biomarker, b) The total serum/plasma biomarker concentration is largely determined by the carrier protein clearance rate, not the unbound biomarker clearance rate itself, and c) Examination of the LMM species bound to a specific carrier protein may contain important diagnostic information. These findings shift the focus of biomarker detection to the carrier protein and its biomarker content.
212 citations
TL;DR: Treatment of serum samples with Affi‐Gel Blue or Aurum kit before 2‐DE analysis can be used to remove high abundance proteins in order to increase the detection sensitivity of proteins present in low abundance.
Abstract: Proteomic technologies are being used to discover and identify disease-associated biomarkers. The application of these technologies in the search for potential diagnostic/prognostic biomarkers in the serum of patients has been limited by the presence of highly abundant albumin and immunoglobulins that constitute approximately 60-97% of the total serum proteins. The purpose of the study was to evaluate whether treatment of human serum with Affi-Gel Blue alone or in combination with Protein A (Aurum serum protein mini kit, Bio-Rad) before two-dimensional gel electrophoresis (2-DE) analysis removed high abundance proteins to allow the visualization of low abundant proteins. Serum samples were treated with either Affi-Gel Blue or Aurum kit and then subjected to 2-DE using 11 cm, pH 4-7 isoelectric focussing strips for the first dimension and 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis for second dimension. Protein spots were visualized using a fluorescent protein dye (SYPRO Ruby, Bio-Rad). Comparison between treatment methods showed significant removal of albumin by both Affi-Gel Blue and Aurum kit and considerable differences in the protein profile of the gels after each treatment. Direct comparison between treatments revealed twenty-eight protein spots unique to Affi-Gel Blue while only two spots were unique after Aurum kit treatment. Unique spots in Affi-Gel Blue and Aurum kit treated serum were not visualized in untreated serum. Sixteen hours of Affi-Gel Blue treatment resulted in enhanced visualization of fifty-three protein spots by two-fold, thirty-one by five-fold, twelve by ten-fold and six by twenty-fold. In parallel after Aurum kit treatment two-, five-, ten- and twenty-fold enhancements of thirty, thirteen, eight and five protein spots, respectively, were observed. The pattern of increased visualization of protein spots with both treatment methods was similar. In conclusion, treatment of serum samples with Affi-Gel Blue or Aurum kit before 2-DE analysis can be used to remove high abundance proteins in order to increase the detection sensitivity of proteins present in low abundance.
199 citations
TL;DR: Analysis of x-ray crystal structures of human albumin suggests that fatty acid binding to site 2 triggers a spring-lock mechanism, which disengages the upper and lower halves of the metal site, which provides a possible mechanism whereby fatty acids could influence the transport and delivery of zinc in blood.
Abstract: Albumin is the major transport protein in blood for Zn(2+), a metal ion required for physiological processes and recruited by various drugs and toxins. However, the Zn(2+)-binding site(s) on albumin is ill-defined. We have analyzed the 18 x-ray crystal structures of human albumin in the PDB and identified a potential five-coordinate Zn site at the interface of domains I and II consisting of N ligands from His-67 and His-247 and O ligands from Asn-99, Asp-249, and H(2)O, which are the same amino acid ligands as those in the zinc enzymes calcineurin, endonucleotidase, and purple acid phosphatase. The site is preformed in unliganded apo-albumin and highly conserved in mammalian albumins. We have used (111)Cd NMR as a probe for Zn(2+) binding to recombinant human albumin. We show that His-67 --> Ala (His67Ala) mutation strongly perturbs Cd(2+) binding, whereas the mutations Cys34Ala, or His39Leu and Tyr84Phe (residues which may H-bond to Cys-34) have no effect. Weak Cl(-) binding to the fifth coordination site of Cd(2+) was demonstrated. Cd(2+) binding was dramatically affected by high fatty acid loading of albumin. Analysis of the x-ray structures suggests that fatty acid binding to site 2 triggers a spring-lock mechanism, which disengages the upper (His-67Asn-99) and lower (His-247Asp-249) halves of the metal site. These findings provide a possible mechanism whereby fatty acids (and perhaps other small molecules) could influence the transport and delivery of zinc in blood.
TL;DR: In this article, a calorimetric study of thermal denaturation of bovine serum albumin in aqueous solutions has shown essential differences in stability of fatty acid containing and defatted albumin.
Abstract: A calorimetric study of thermal denaturation of bovine serum albumin in aqueous solutions has shown essential differences in stability of fatty acid containing and defatted albumin. The first one shows a single endotherm peak in DSC curve near 69°C with enthalpy change about 1000 kJ mol-1. Defated albumin melts in two different temperature ranges: near 56 and 69°C with enthalpy changes about 300 and 200 kJ mol-1 respectively. Deconvolution analysis shows that the single endotherm is well approximated as the sum of three independent two-state transitions. Two transitions of bimodal DSC curve for defatted albumin are not of a two-state type. This molecule melts probably as two structurally independent parts.
TL;DR: In this article, a nonviral gene delivery vehicle consisting of DNA, human serum albumin (HSA) and polyethylenimine (PEI) nanoparticles containing the pGL3 vector coding for luciferase as a reporter gene were formed by charge neutralization.
TL;DR: The data suggest that the heart is especially effective in removal of circulating TG and core lipids and that this is due to LPL hydrolysis and not its bridging function.
Abstract: Long-chain fatty acids (FA) supply 70–80% of the energy needs for normal cardiac muscle. To determine the sources of FA that supply the heart, [14C]palmitate complexed to bovine serum albumin and [...
TL;DR: The results demonstrate that MCP-1 plays an important role in the development of tubulointerstitial inflammation, tubular damage, and fibrosis induced by proteinuria, and the fact that 7ND gene therapy had little effect on the contralateral kidney indicates that7ND acted locally.
Abstract: It has been postulated that protein filtered through glomeruli activates tubular epithelial cells, which secrete vasoactive and inflammatory substances including chemokines, leading to tubulointerstitial renal injury. The present study was designed to investigate the role of monocyte chemoattractant protein-1 (MCP-1) in this process and to evaluate the effectiveness of a kidney-targeted gene transfer technique using hydrodynamic pressure. Naked plasmid encoding 7ND (an MCP-1 antagonist) or a control plasmid was introduced into the left kidney of rats. Three days after gene transfer (day 0), intraperitoneal administration of bovine serum albumin (10 mg/g body wt per day) was started and continued for 14 or 21 d. RT-PCR showed that 7ND mRNA was expressed only in the gene-transfected kidney. Immunostaining showed that 7ND protein was localized in the interstitial cells. Macrophage infiltration was significantly reduced in the left kidney of rats treated with 7ND on days 14 and 21. In the right kidney, such effects were not observed. 7ND also attenuated tubular damage and decreased the number of apoptotic cells. Computer-assisted analysis revealed that the areas positively stained for alpha-smooth muscle actin (alpha SMA), fibronectin-EDA, type I collagen, and collagen fibrils were significantly reduced in the 7ND-treated kidney on day 21. Furthermore, 7ND gene therapy significantly reduced MCP-1 and TGF-beta 1 mRNA expression. These results demonstrate that MCP-1 plays an important role in the development of tubulointerstitial inflammation, tubular damage, and fibrosis induced by proteinuria. The fact that 7ND gene therapy had little effect on the contralateral kidney indicates that 7ND acted locally. This strategy may have a potential usefulness as a gene therapy against tubulointerstitial renal injury.
TL;DR: It is found that a baseline serum albumin level was a powerful prognostic variable, which accounted for 7.35% of the variation in patient survival time.
Abstract: BACKGROUND: The medical literature shows several examples of an inverse relationship between serum albumin levels and survival in patients with advanced cancer. METHODS: We investigated the effect of baseline serum levels on 180 consecutively treated patients who were diagnosed with breast cancer from March 1993 to December 1999 at our institution. We investigated the effect of low levels of serum albumin ( 3.5 g/dL) reduced the risk of death by 72% (p = .0033). Only tumor stage had a larger impact on ...
Journal Article•
TL;DR: MTX-HSA is effectively taken up by the cells via albumin receptor- or folate receptor-mediated endocytosis and time-dependently released as an active compound into the cytosol to exert an inhibiting effect on TS and to induce cell cycle alterations.
Abstract: To avoid systemic toxicity of the cytotoxic drug methotrexate (MTX) and to improve tumor selectivity, MTX was bound to human serum albumin (HSA) as a drug carrier. To understand more about the mechanism of action of MTX conjugated to HSA (MTX-HSA), the uptake of MTX-HSA into the cell was determined as well as the effect of MTX-HSA on thymidylate synthase (TS), cell cycle distribution, and cell proliferation. Different uptake kinetics were observed for [(3)H]MTX and [(3)H]MTX-HSA. However, similar uptake kinetics were measured for (125)I-HSA and (125)I-MTX-HSA (2.1 and 1.8 pmol/10(7) cells/h when cells were treated with 10 micro M (125)I-HSA and (125)I-MTX-HSA, respectively), suggesting that MTX-HSA enters the cells by albumin-mediated endocytosis. We observed no effect of MTX-HSA on TS when folate receptor-expressing KB cells were treated for 4 h (IC(50), >50 micro M). However, 24 h after incubation, MTX-HSA inhibited TS with an IC(50) of 6.9 micro M. In addition, we found that MTX-HSA had a delayed effect on the cell cycle compared with MTX and that this effect could be inhibited with the lysosomal inhibitor methylamine, suggesting that MTX-HSA activity is dependent on lysosomal processes. The proliferation of different wild-type and MTX-resistant tumor cell lines was inhibited at IC(50) concentrations between 2 and 78 micro M, respectively. MTX-HSA accumulates in vivo in the tumor tissue. Local concentrations of 18-29 micro M were measured, which are effective antiproliferative concentrations as determined in vitro. We also investigated the antitumor activity of MTX-HSA in vivo in different human tumor xenografts grown s.c. in nude mice. Fourteen tumors from eight different tissues were tested. Nine of 14 tumors (64%) showed a clear response with tumor inhibition, stasis, or regression; 5 of 14 (36%) gave a moderate response with tumor growth delay or no response. In conclusion, MTX-HSA is effectively taken up by the cells via albumin receptor- or folate receptor-mediated endocytosis and time-dependently released as an active compound into the cytosol to exert an inhibiting effect on TS and to induce cell cycle alterations. In vivo, effective concentrations of MTX-HSA were reached in tumor tissue to exhibit antitumor activity.
TL;DR: It is demonstrated that SCCA1 can be detected by LC-MS in patient serum following depletion of albumin and gamma-globulins thus opening the possibility of screening patient sera for other, so far unknown, tumor markers.
TL;DR: The results suggest that BCAAs, especially leucine, promote the production of albumin in rat primary hepatocytes through an mTOR signal transduction system.
TL;DR: Findings indicate that ERK signaling is involved in BSA-induced MCP-1 expression in mProx cells.
Abstract: Persistent proteinuria has been indicated to be a major risk factor for the development of tubulointerstitial damage through a process of proinflammatory molecule expression. Monocyte chemoattracta...
TL;DR: It is concluded that the dextran-grafted branched PEI improved the stability of the DNA-polymer complexes and showed potential to conjugate with ligands for in vivo targeted gene delivery.
TL;DR: Up-regulated cellular Fn mRNA messages, assessed using RT-PCR techniques, supported HUVECs' producing the endogenous extracellular matrix (ECM) protein Fn in order to attach and survive on the suboptimal Teflon AF culture surfaces.
Abstract: Fibronectin (Fn) adsorption was studied on different commercial polymer surface chemistries, including tissue culture polystyrene (TCPS), bacteriologic polystyrene (BPS), fluoropolymer Teflon AF, and poly-L-lactide (PLLA). Antibody probes detected the availability of Fn's cell binding domain on adsorbed Fn in the competitive presence and absence of bovine serum albumin (BSA). Domain availability was highest for Fn adsorbed on TCPS, especially in the presence of either serum albumin or dilute serum. Attachment and growth efficiencies for human umbilical venous endothelial cells (HUVECs) cultured on surfaces preadsorbed with Fn in serum and serum-free media correlated with antibody cell-binding domain availability: TCPS > BPS, Teflon AF > PLLA. Intracellular signaling from the GTPase, RhoA, was highest (RhoA:RhoGDI inhibitor ratio) in cells cultured on the Teflon AF surfaces, indicating that despite lower attached cell numbers on Teflon AF compared to TCPS, cell signaling remained activated after 24 h of growth. Up-regulated cellular Fn mRNA messages, assessed using RT-PCR techniques, supported HUVECs' producing the endogenous extracellular matrix (ECM) protein Fn in order to attach and survive on the suboptimal Teflon AF culture surfaces.
TL;DR: The positive glycation inhibitory and antioxidative activities of these plants might suggest a possible role in targeting aging and diabetic complications.
Abstract: The protein glycation inhibitory activity of aqueous ethanolic extracts from 25 plant tissues was evaluated in vitro using the model system of bovine serum albumin and fructose. The most bioactive ...
TL;DR: The binding stoichiometry of allopurinol–mercaptopurine–serum albumin complex was studied and the character of the binding between studied quencher and human and bovine serum albumin was estimated.
TL;DR: In this article, the authors analyzed albumin and creatinine levels as outcome variables and their association with C-reactive protein (CRP), equilibrated normalized protein catabolic rate (enPCR), and serum bicarbonate level as independent variables from laboratory data obtained from patients in the Hemodialysis Study.
TL;DR: Equilibrium dialysis revealed a 78% binding of PTH to albumin and the withdrawal of albumin from the powder increased absolute bioavailability after inhalation, which makes it a promising alternative to subcutaneous injection.
TL;DR: The release of albumin from the chitosan-coated pectin beads was dependent on pH of coating solution and release medium, which might affect the degree of swelling of pECTin beads.
TL;DR: The present results suggest that binding to plasma proteins causes a drastic decrease of NAMI-A bioavailability and a subsequent reduction of its biological activity, implying that association to Plasma proteins essentially represents a mechanism of drug inactivation.
Abstract: NAMI-A is an innovative ruthenium(III) complex with a very encouraging preclinical profile of metastasis inhibition, which is undergoing initial phases of clinical trials. To assess the pharmacological relevance of the drug fraction associated to plasma proteins, adducts of NAMI-A with either serum albumin or serum transferrin were prepared and their biological effects tested in vitro and in vivo. Specifically, adducts of NAMI-A with either serum albumin or serum transferrin, prepared and characterized at a ruthenium-to-protein molar ratio of 4:1, were evaluated in vitro on the KB human tumor cell line and in vivo on the MCa mammary carcinoma tumor. The effects of NAMI-A/protein adducts on cell viability and on cell cycle progression were found to be far smaller than those produced by free NAMI-A. GFAAS measurements point out that the amount of ruthenium that gets into cells is drastically reduced when NAMI-A is presented in its protein-bound form. In vivo use of NAMI-A adducts with albumin and transferrin resulted markedly less effective on lung metastasis reduction, than free NAMI-A. Overall, the present results suggest that binding to plasma proteins causes a drastic decrease of NAMI-A bioavailability and a subsequent reduction of its biological activity, implying that association to plasma proteins essentially represents a mechanism of drug inactivation.
TL;DR: In the presence of sodium dodecyl sulfate (SDS), the secondary structure of bovine serum albumin (BSA) was almost protected against thermal denaturation above 50 degrees C, where the structural change became irreversible.
TL;DR: When treated with a vitamin B12-B6-folate combination, patients with mild cognitive impairment and hyperhomocysteinaemia appear to improve their blood-brain barrier function and may also stabilise their cognitive status.
Abstract: Thirty patients had mild cognitive impairment and increased homocysteine levels in serum. On average, they were supplemented orally with a high dose of a vitamin B12-B6-folate combination for 270 days. All patients had normal serum B12 and folate levels at baseline. Cerebrospinal fluid levels of the tau protein (CSF-tau) and the albumin ratio were measured before and after treatment. The serum homocysteine levels were normalised after treatment. The albumin ratio significantly correlated with vascular risk factors. At baseline, the ratio was higher in the patients in comparison with age-matched controls. After treatment, the ratio was significantly reduced, which may indicate a tightening of the blood-brain barrier. The CSF-tau levels did not change significantly although there was a numeric decline. None of the patients progressed into dementia during the treatment period. When treated with a vitamin B12-B6-folate combination, patients with mild cognitive impairment and hyperhomocysteinaemia appear to improve their blood-brain barrier function. They may also stabilise their cognitive status. Further investigations are warranted on the role of blood-brain barrier dysfunction in the pathogenesis of dementia.