Biomedical subjects

Min Lu

Publications and source records attributed to Min Lu.

At least 55 records · Page 3Linked to original sources

PubMed2005

PINCH1 plays an essential role in early murine embryonic development but is dispensable in ventricular cardiomyocytes.

PINCH1, an adaptor protein composed of five LIM domains, mediates protein-protein interactions and functions as a component of the integrin-integrin-linked kinase (ILK) complex. The integrin-ILK signaling complex plays a pivotal role in cell motility, proliferation, and survival during embryonic development of many animal species. To elucidate the physiological function of PINCH1 in mouse embryonic development, we have deleted the mouse PINCH1 gene by homologous recombination. Mice heterozygous for PINCH1 are viable and indistinguishable from wild-type littermates. However, no viable homozygous offspring were observed from PINCH1+/- intercrosses. Histological analysis of homozygous mutant embryos revealed that they had a disorganized egg cylinder by E5.5, which degenerated by E6.5. Furthermore, E5.5 PINCH1-/- embryos exhibited decreased cell proliferation and excessive cell death. We have also generated and analyzed mice in which PINCH1 has been specifically deleted in ventricular cardiomyocytes. These mice exhibit no basal phenotype, with respect to mouse survival, cardiac histology, or cardiac function as measured by echocardiography. Altogether, these data indicate that PINCH1 plays an essential role in early murine embryonic development but is dispensable in ventricular cardiomyocytes.

Adaptor Proteins, Signal Transducing↗

PubMed2005

Cloning, expression, purification, and characterization of LC-1 ScFv with GFP tag.

Total RNA was isolated from the hybridoma cell line (LC-1), which secretes anti-lung adenocarcinoma monoclonal antibody, and was transferred into cDNA. Based on the FR1 (framework region 1) and FR4 conserved regions of LC-1 gene, the variable regions of heavy chain (Vh) and light chain (Vl) were amplified, and the Vh and modified Vl were connected to single chain Fv (ScFv) by SOE-PCR (splice overlap extension PCR). The modified ScFv was fused with green fluorescent protein (GFP) and introduced into E. coli JM109. The fusion protein induced by IPTG (Isopropylthiogalactoside) was about 57000 on a 10% SDS-PAGE gel (10% Sds Polyacrylamide Gel Electrophoresis), and primarily manifested as inclusion bodies. The renatured protein purified by Ni-NTA Superflow resins showed ability to bind to antigen on SPC-A-1 lung adenocarcinoma. In addition, the induced host cells fluoresced bright green under 395 nm wavelength, which indicated that the expected protein with dual activity was expressed in the prokaryotic system. The ScFv with GFP tag used in this research can be applied as a new reagent to detect immunological dye, and provide a feasible way to detect adenocarcinoma in a clinical setting.

Adenocarcinoma↗

PubMed2005

Correlation of murine embryonic stem cell gene expression profiles with functional measures of pluripotency.

Global gene expression profiling was performed on murine embryonic stem cells (ESCs) induced to differentiate by removal of leukemia inhibitory factor (LIF) to identify genes whose change in expression correlates with loss of pluripotency. To identify appropriate time points for the gene expression analysis, the dynamics of loss of pluripotency were investigated using three functional assays: chimeric mouse formation, embryoid body generation, and colony-forming ability. A rapid loss of pluripotency was detected within 24 hours, with very low residual activity in all assays by 72 hours. Gene expression profiles of undifferentiated ESCs and ESCs cultured for 18 and 72 hours in the absence of LIF were determined using the Affymetrix GeneChip U74v2. In total, 473 genes were identified as significantly differentially expressed, with approximately one third having unknown biological function. Among the 275 genes whose expression decreased with ESC differentiation were several factors previously identified as important for, or markers of, ESC pluripotency, including Stat3, Rex1, Sox2, Gbx2, and Bmp4. A significant number of the decreased genes also overlap with previously published mouse and human ESC data. Furthermore, several membrane proteins were among the 48 decreased genes correlating most closely with the functional assays, including the stem cell factor receptor c-Kit. Through identification of genes whose expression closely follows functional properties of ESCs during early differentiation, this study lays the foundation for further elucidating the molecular mechanisms regulating the maintenance of ESC pluripotency and facilitates the identification of more reliable molecular markers of the undifferentiated state.

Animals↗

PubMed2005

[Expression of macrophage inflammatory protein-1alpha, a disintegrin-like and metalloproteinase 8 and 12, and CD68 protein in giant cell lesions of jaw and giant cell tumors of long bone].

OBJECTIVE: To detect the expression of macrophage inflammatory protein-1alpha (MIP-1alpha), a disintegrin-like and metalloproteinase (ADAM) 8 and 12 and CD68 protein in giant cell lesions of jaw and giant cell tumors of long bone, and to study their effects on the histogenesis of giant cells in such lesions. METHODS: MIP-1alpha, ADAM8, ADAM12 and CD68 were detected by immunohistochemistry in 24 paraffin-embedded specimens of central giant cell lesions of jaw and giant cell tumors respectively. RESULTS: MIP-1alpha positive signal was located in blood vessels and bone. ADAM8, ADAM12 and CD68 positive signals were located in the cell membrane and cytoplasm of all multinucleated giant cells and some round mononuclear cells in the lesions. In addition, some spindle mononuclear stromal cells were positive for ADAM12 in both lesions. CONCLUSION: Multinucleated giant cells probably originate from CD68-postive round mononuclear cells, which are recruited from monocyte-macrophage system by chemokines, such as MIP-1alpha, followed by cell fusion mediated by ADAM8 and ADAM12.

ADAM Proteins↗

PubMed2005

[Lung pathology and pathogenesis of severe acute respiratory syndrome: a report of six full autopsies].

OBJECTIVE: Severe acute respiratory syndrome (SARS) is an emerging infectious disease that first manifested in humans in November 2002. The SARS-associated coronavirus (SARS-CoV) has been identified as the causal agent, but the pathology and pathogenesis are still not quite clear. METHODS: Post-mortem lung samples from six patients who died from SARS from April to July 2003 were studied by light and electron microscopy, Masson trichromal staining and immunohistochemistry. Evidence of infection with the SARS-CoV was determined by reverse-transcription PCR (RT-PCR) , serological examination and electron microscopy. RESULTS: Four of six patients had serological and RT-PCR evidence of recent infection of SARS-CoV. Morphologic changes are summarized as follows: (1) Diffuse and bilateral lung consolidation was seen in all patients (6/6) with increasing lung weight. (2) Diffuse alveolar damage was universal (6/6) with hyaline membrane formation (6/6), intra-alveolar edema/hemorrhage (6/6), fibrin deposition (6/6), pneumocyte desquamation (6/6). A marked disruption in the integrity of the alveolar epithelium was confirmed by immunostaining for the epithelial marker AE1/AE3 (6/6). (3) Type II pneumocytes, with mild hyperplasia, atypia, cytomegaly with granular amphophilic cytoplasm and intracytoplasmic lipid accumulation (5/6). (4) Giant cells in the alveoli were seen in five of 6 patients (5/6) , most of which were positive for the epithelial marker AE1/AE3 (5/6), but some cells were positive for the macrophage marker CD68(2/6). (5) A pronounced increase of macrophages were seen in the alveoli and the interstitium of the lung (6/6), which was confirmed by histological study and immunohistochemistry. (6) Haemophagocytosis was present in five of the 6 patients(5/6). (7) Lung fibrosis was seen in five patients(5/6), with alveolar septa and interstitium thickening(5/6), intraalveolar organizing exudates (6/6) and pleura thickening (4/6). Proliferation of collagen was confirmed by Masson trichromal staining, most of which was type III collagen by immunostaining. The formation of distinctive fibroblast/myofibroblast foci was seen in five patients (5/6) by light microscopy and immunochemistry. (8) Squamous metaplasia of bronchial mucosa was seen in five patients(5/6). (9) Thrombi was seen in all patients(6/6). (10) Accompanying infection was present in two patients, one was bacteria, the other was fungus. In addition, electron microscopy revealed viral particles in the cytoplasm of alveolar epithelial cells and endothelial cells corresponding to coronavirus. CONCLUSION: Direct injury of SARS-CoV on alveolar epithelium, prominent macrophage infiltration and distinctive fibroblast/myofibroblast proliferation may play major roles in the pathogenesis of SARS.

Adult↗

PubMed2004

Kinetics and thermodynamics of the unfolding and refolding of the three-stranded alpha-helical coiled coil, Lpp-56.

Temperature-induced reversible unfolding and refolding of the three-stranded alpha-helical coiled coil, Lpp-56, were studied by kinetic and thermodynamic methods, using CD spectroscopy, dynamic light scattering, and scanning calorimetry. It was found that both unfolding and refolding reactions of this protein in neutral solution in the presence of 100 mM NaCl are characterized by unusually slow kinetics, which permits detailed investigation of the mechanism of these reactions. Kinetic analyses show that the unfolding of this coiled coil represents a single-stage first-order reaction, while the refolding represents a single-stage third-order reaction. The activation enthalpy and entropy for unfolding do not depend noticeably on temperature and are both significantly greater than those for the folding reaction, which show a significant dependence on temperature. The activation heat capacity change for the unfolding reaction is close to zero, while it is quite significant for the folding reaction. The correlation between the activation and structural parameters obtained for the Lpp-56 coiled coil suggests that interhelical van der Waals interactions are disrupted in the transition state, which is nevertheless still compact, and water has not yet penetrated into the interface; the transition from the transient state to the unfolded state results in hydration of exposed apolar groups of the interface and the disruption of helices. The low propensity for the Lpp-56 strands to fold and associate is caused by the high number of charged groups at neutral pH. On one hand, these charges give rise to considerable repulsive forces destabilizing the helical conformation of the strands. On the other hand, they align the folded helices in parallel and in register so that the apolar sides face each other, and the oppositely charged groups may form salt links, which are important for the formation of the trimeric coiled coil. A decrease in pH, which eliminates the salt links, dramatically decreases the stability of Lpp-56; its structure becomes less rigid and unfolds much faster.

Amino Acid Sequence↗

PubMed2004

The ARE-dependent mRNA-destabilizing activity of BRF1 is regulated by protein kinase B.

Butyrate response factor (BRF1) belongs to the Tis11 family of CCCH zinc-finger proteins, which bind to mRNAs containing an AU-rich element (ARE) in their 3' untranslated region and promote their deadenylation and rapid degradation. Independent signal transduction pathways have been reported to stabilize ARE-containing transcripts by a process thought to involve phosphorylation of ARE-binding proteins. Here we report that protein kinase B (PKB/Akt) stabilizes ARE transcripts by phosphorylating BRF1 at serine 92 (S92). Recombinant BRF1 promoted in vitro decay of ARE-containing mRNA (ARE-mRNA), yet phosphorylation by PKB impaired this activity. S92 phosphorylation of BRF1 did not impair ARE binding, but induced complex formation with the scaffold protein 14-3-3. In vivo and in vitro data support a model where PKB causes ARE-mRNA stabilization by inactivating BRF1 through binding to 14-3-3.

14-3-3 Proteins↗

PubMed2004

Atomic structure of a tryptophan-zipper pentamer.

Coiled-coil motifs are ubiquitous mediators of specific protein-protein interactions through the formation of interlocking hydrophobic seams between alpha-helical chains. Residues that form these seams occur at the first (a) and fourth (d) positions of a characteristic 7-aa repeat and are primarily aliphatic. The potential of aromatic residues to promote helix association in a coiled coil was explored by engineering a "Trp-zipper" protein with Trp residues at all 14 a and d positions. The protein forms a discrete, stable, alpha-helical pentamer in water at physiological pH. Its 1.45-A crystal structure reveals a parallel, five-stranded coiled coil, a previously uncharacterized type of "knobs-into-holes" packing interaction between interfacial Trp side chains, and an unusual approximately 8-A-diameter axial channel lined with indole rings that is filled with polyethylene glycol 400 and water and sulfate ion molecules. The engineered Trp-zipper pentamer enlarges current views of coiled-coil assembly, molecular recognition, and protein engineering, and may serve as a soluble model for membrane ion channels.

Amino Acid Motifs↗

PubMed2004

Endoplasmic reticulum degradation impedes olfactory G-protein coupled receptor functional expression.

BACKGROUND: Research on olfactory G-protein coupled receptors (GPCRs) has been severely impeded by poor functional expression in heterologous systems. Previously, we demonstrated that inefficient olfactory receptor (OR) expression at the plasma membrane is attributable, in part, to degradation of endoplasmic reticulum (ER)-retained ORs by the ubiquitin-proteasome system and sequestration of ORs in ER aggregates that are degraded by autophagy. Thus, experiments were performed to test the hypothesis that attenuation of ER degradation improves OR functional expression in heterologous cells. RESULTS: To develop means to increase the functional expression of ORs, we devised an approach to measure activation of the mOREG OR (Unigene # Mm.196680; Olfr73) through coupling to an olfactory cyclic nucleotide-gated cation channel (CNG). This system, which utilizes signal transduction machinery coupled to OR activation in native olfactory sensory neurons, was used to demonstrate that degradation, both by the ubiquitin-proteasome system and autophagy, limits mOREG functional expression. The stimulatory effects of proteasome and autophagy inhibitors on mOREG function required export from the ER and trafficking through the biosynthetic pathway. CONCLUSIONS: These findings demonstrate that poor functional expression of mOREG in heterologous cells is improved by blocking proteolysis. Inhibition of ER degradation may improve the function of other ORs and assist future efforts to elucidate the molecular basis of odor discrimination.

Animals↗

PubMed2004

A preliminary study on DNA detection based on relative magnetic permeability measurements and histone H1 conjugated superparamagnetic nanoparticles as magnetic tracers.

Histone H1 conjugated superparamagnetic nanoparticles were assessed for their ability to work as magnetic tracers in conjunction with the relative magnetic permeability metre (MPM-100) for the detection and quantification of DNA (deoxyribonucleic acid). The method employed was based on the electrostatic adsorption of DNA (analyte) to amino group derivatised silica (carrier) and subsequent binding of histone H1 conjugated superparamagnetic nanoparticles (magnetic tracer). The sandwich complexes formed were separated from the medium by sedimentation and the relative magnetic permeability of the sediments were measured with the MPM-100. Investigations were made with both calf thymus DNA and plasmid DNA in aqueous buffered solution as well as in a lysed cell culture with high protein content. For the quantification of calf thymus DNA, a linear relationship between the DNA concentration in the sample and the relative magnetic permeability of the pellet was found for DNA concentrations up to 67 microg/ml in buffered solutions as well as in a lysed cell culture. The limits of detection were determined to 12 and 31 microg/ml, respectively. For the quantification of plasmid DNA in buffered solution a linear range was established for concentrations in up to 150 microg/ml and the limit of detection was determined to 52 microg/ml.

Animals↗

PubMed2004

Dual effects of glutathione-S-transferase pi on As2O3 action in prostate cancer cells: enhancement of growth inhibition and inhibition of apoptosis.

To determine the effects of glutathione-S-transferase pi (GSTpi) on the actions of As2O3, As2O3-induced growth inhibition and apoptosis was studied in three prostate cancer cell lines: DU-145, PC-3 and LNCaP cells. As2O3 inhibited cell proliferation of DU-145 and PC-3 cells (both cells express GSTpi), but not of LNCaP cells (which lack GSTpi expression) at concentrations below 1 microM. LNCaP cells stably transfected and expressed GSTpi (LNCaP/GSTpi) became sensitive to As2O3 growth inhibition. As2O3 arrested cell growth of DU-145, PC-3 and LNCaP/GSTpi cells in the G2/M phase of the cell cycle at low concentrations (<2 microM), but did not induce apoptosis. At higher concentrations (10-20 microM), As2O3 induced apoptosis in LNCaP cells, but not in DU-145 or PC-3 cells. The apoptosis induction due to As2O3 treatment of LNCaP cell correlated with the activation of JNK and p38 and induction of p53 protein. LNCaP/GSTpi cells became insensitive to As2O3-induced apoptosis with reduced JNK activition. These data indicate that GSTpi increases growth inhibition due to As2O3 treatment and prevents As2O3-induced apoptosis in prostate cancer cells. Therefore, it appears that As2O3 inhibits cell growth and induces apoptosis through different mechanisms.

Animals↗

PubMed2004

Structure and protein design of a human platelet function inhibitor.

Hematophagous arthropods secrete a salivary apyrase that inhibits platelet activation by catabolizing ADP released from damaged tissues and blood cells. We report the X-ray crystal structures of a human enzyme of the soluble apyrase family in its apo state and bound to a substrate analog. The structures reveal a nucleotide binding domain comprising a five-blade beta propeller, binding determinants of the substrate and the active site, and an unusual calcium binding site with a potential regulatory function. Using a comparative structural biology approach, we were able to redesign the human apyrase so as to enhance its ADPase activity by more than 100-fold. The engineered enzyme is a potent inhibitor of platelet aggregation and may serve as the basis for the development of a new class of antithrombotic agents.

Amino Acid Sequence↗

PubMed2004

Hemangiopoietin, a novel human growth factor for the primitive cells of both hematopoietic and endothelial cell lineages.

The cells of hematopoietic and vascular endothelial cell lineages are believed to share a common precursor, termed hemangioblast. However, the existence of a growth factor acting relatively specifically on hemangioblasts remains unclear. Here we report the identification of hemangiopoietin (HAPO), a novel growth factor acting on both hematopoietic and endothelial cell lineages. In vitro in the human system, recombinant human HAPO (rhHAPO) significantly stimulated the proliferation and hematopoietic and/or endothelial differentiation of human bone marrow mononuclear cells and of purified CD34+, CD133+, kinase domain receptor-positive (KDR+), or CD34+/KDR+ cell populations. In the murine system, rhHAPO stimulated the proliferation of long-term culture-initiating cells (LTC-ICs) as well as CD34+ and stem cell antigen-1 (Sca-1+) cell subsets. In vivo, subcutaneous injection of rhHAPO into normal mice resulted in a significant increase in bone marrow hematopoietic cells. Furthermore, irradiated mice injected with rhHAPO had an enhanced survival rate and accelerated hematopoiesis. Our data suggest that HAPO is a novel growth factor acting on the primitive cells of both hematopoietic and endothelial cell lineages and that HAPO may have a clinical potential in the treatment of various cytopenias and radiation injury and in the expansion of hematopoietic and endothelial stem/progenitor cells.

Abortion, Spontaneous↗

PubMed2004

Fast folding of the HIV-1 and SIV gp41 six-helix bundles.

Human (HIV-1) and simian (SIV) immunodeficiency virus fusion with the host cell is promoted by the receptor-triggered refolding of the gp41 envelope protein into a stable trimer-of-hairpins structure that brings viral and cellular membranes into close proximity. The core of this hairpin structure is a six-helix bundle in which an inner homotrimeric coiled coil is buttressed by three antiparallel outer HR2 helices. We have used stopped-flow circular dichroism spectroscopy to characterize the unfolding and refolding kinetics of the six-helix bundle using the HIV-1 and SIV N34(L6)C28 polypeptides. In each case, the time-course of ellipticity changes in refolding experiments is well described by a simple two-state model involving the native trimer and the unfolded monomers. The unfolding free energy of the HIV-1 and SIV trimers and their urea dependence calculated from kinetic data are in very good agreement with data measured directly by isothermal unfolding experiments. Thus, formation of the gp41 six-helix bundle structure involves no detectable population of stable, partly folded intermediates. Folding of HIV-1 N34(L6)C28 is five orders of magnitudes faster than folding of its SIV counterpart in aqueous buffer: k(on),(HIV-1)=1.3 x 10(15)M(-2)s(-1) versus k(on),(SIV)=1.1 x 10(10)M(-2)s(-1). The unfolding rates are similar: k(off),(HIV-1)=1.1 x 10(-5)s(-1) versus k(off),(SIV=)5.7 x 10(-4)s(-1). Kinetic m-values indicate that the transition state for folding of the HIV-1 protein is significantly more compact than the transition state of the SIV protein. Replacement of a single SIV threonine by isoleucine corresponding to position 573 in the HIV-1 sequence significantly stabilizes the protein and renders the folding rate close to that of the HIV-1 protein yet without making the transition state of the mutant as compact as that of the HIV-1 protein. Therefore, the overall reduction of surface exposure in the high-energy transition state seems not to account for different folding rates. While the available biological evidence suggests that refolding of the gp41 protein is slow, our study implies that structural elements outside the trimer-of-hairpins limit the rate of HIV-1 fusion kinetics.

Animals↗

PubMed2004

ATF6 modulates SREBP2-mediated lipogenesis.

Activating transcription factor 6 (ATF6) and sterol regulatory element-binding proteins (SREBPs) are activated by proteolytic cleavage. The ensuing nuclear translocation of their N-termini (i.e., ATF6(N) and SREBP(N)) activates the respective target genes involved in unfolded protein response and lipogenesis. Here, we report that glucose deprivation activated ATF6 but suppressed the SREBP2-regulated transcription. Overexpression of ATF6(N) had similar inhibitory effects on SREBP2-targeted genes. The blockade of ATF6 cleavage by BiP/grp78 reversed this inhibitory effect. GST pull-down and immunoprecipitation assays revealed that ATF6(N) bound to SREBP2(N). Deletion analysis of the various functional domains of ATF6 indicated that the interaction was through its leucine-zipper domain. Chromatin immunoprecipitation assays revealed that ATF6(N) formed a complex with the SRE-bound SREBP2(N). The attenuated transcriptional activity of SREBP2 was due, in part, to the recruitment of HDAC1 to the ATF6-SREBP2 complex. As a functional consequence, the lipogenic effect of SREBP2(N) in liver cells was suppressed by ATF6(N). Our results provide a novel mechanism by which ATF6 antagonizes SREBP2 to regulate the homeostasis of lipid and glucose.

Activating Transcription Factor 6↗

PubMed2004

Utility of serum CA19-9 in diagnosis of cholangiocarcinoma: in comparison with CEA.

AIM: The diagnosis of cholangiocarcinoma is often difficult, making management approaches problematic. A reliable serum marker for cholangiocarcinoma would be a useful diagnostic test. The aims of our study were to evaluate the usefulness of a serum CA19-9 determination in the diagnosis of cholangiocarcinoma. METHODS: We prospectively measured serum CA19-9 and CEA concentrations in patients with cholangiocarcinoma (n=35), benign biliary diseases (n=92), and healthy individuals (n=15). Serum CA19-9 and CEA concentrations were measured by an immunoradiometric assay without knowledge of the clinical diagnosis. RESULTS: The sensitivity of a CA19-9 value >37 KU/L(-1) and a CEA value >22 microg/L(-1) in diagnosing cholangiocarcinoma were 77.14% and 68.57%, respectively. When compared with the benign biliary diseases group, the true negative rates of serum CA19-9 and CEA were 84.78% and 81.52%, respectively. The false positive rates of serum CA19-9 and CEA were 15.22% and 18.48%, whereas the accuracy of serum CA19-9 and CEA were 82.68% and 77.95%, respectively. Serum CA19-9 and CEA concentrations were significantly elevated (P<0.001 and P<0.05) in patients with cholangiocarcinoma (290.31+/-5.34 KU/L(-1) and 36.46+/-18.03 microg/L(-1)) compared with patients with benign biliary diseases (13.38+/-2.59 KU/L(-1) and 13.84+/-3.85 microg/L(-1)) and healthy individuals (12.78+/-3.69 KU/L(-1) and 11.48+/-3.37 microg/L(-1)). In 15 patients undergoing curative resection of cholangiocarcinoma, the mean serum CA19-9 concentration was decreased from a preoperative level of 286.41+/-4.36 KU/L(-1) to a postoperative level of 62.01+/-17.43 KU/L(-1) (P<0.001), and the mean serum CEA concentration from 39.41+/-24.35 microg/L(-1) to 28.69+/-11.03 microg/L(-1) (P<0.05). In patients with cholangiocarcinoma, however, no correlation was found between serum CEA and CA19-9 concentrations (r=0.036). CONCLUSION: These data suggest that the serum CA19-9 determination is a useful addition to the available tests for the differential diagnosis of cholangiocarcinoma. Serum CA19-9 is an effective tumor marker in diagnosing cholangiocarcinoma, deciding whether the tumor has been radically resected and monitoring effect of treatment.

Bile Duct Neoplasms↗

PubMed2004

Conformational and enzymatic changes of 20S proteasome of rat natural killer cells induced by mono- and divalent cations.

We have been investigated the relation between activation of "neutral" and "acidic" chymotrypsin-like (ChT-L) activity and conformational changes in the 20S proteasome complex from the rat natural killer (NK) cells induced by SDS, mono- and divalent cations. The conformational changes were monitored by tryptophan fluorescence and light scattering. It was revealed that the changes in the maximum position and contribution of the short-wavelength spectral component correlated with the alteration of ChT-L activity of the proteasome. Statistical analysis was applied to assign the fluorescence components with tryptophan residues based on the classification of calculated structural parameters of the environment of tryptophan fluorophores in protein. It was proposed that the emission of W13 from alpha6-subunit located near the cluster of highly conserved proteasome residues is mostly sensitive to the activation of the enzyme. We concluded that the expression of maximal ChT-L activity of 20S proteasome is associated with the conformational changes occurs in this cluster that lead to the proteasome open conformation, allowing substrate access into the proteolytic chamber.

Animals↗

PubMed2004

Glycoxidation and inflammation in renal failure patients.

BACKGROUND: Inflammation is common in patients with chronic renal failure and has been associated with the increased risk for cardiovascular disease (CVD) in this condition. Advanced glycoxidation end products (AGEs) are among the factors implicated in the inflammatory state of chronic renal failure. METHODS: In a cross-sectional study of 189 dialysis patients, we measured circulating levels of C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha), vascular adhesion molecule-1 (VCAM-1), vascular endothelial growth factor (VEGF), and plasminogen activator inhibitor-1 (PAI-1) to test for possible relationships between them and serum AGE levels. In addition, these parameters were measured in a subgroup of 18 patients with chronic renal failure randomly assigned to a 4-week diet, either low (L-AGE) or high (H-AGE) in AGE content. AGEs were measured by means of a monoclonal antibody against epsilonN-carboxymethyllysine. RESULTS: At baseline, serum AGE levels, as well as those for CRP, TNF-alpha, VCAM-1, and VEGF, were markedly elevated, although no correlation was found between AGE levels and the other markers. Dietary AGE modulation resulted in a significant decrease in levels of serum AGEs, CRP, and PAI-1 in the L-AGE group (approximately 35%, 44%, and 17%, respectively; P < 0.03), whereas only serum AGE levels increased significantly in the H-AGE group. VCAM-1 and TNF-alpha levels, although similar at baseline, became significantly lower in patients on an L-AGE compared with H-AGE diet (P < 0.05) at the end of the study. CONCLUSION: Data from the interventional phase of the study suggest that AGEs have a role in the initiation of the inflammatory state of chronic renal failure, which eventually leads to increased CVD. This finding opens the possibility for using anti-AGE strategies in the prevention and treatment of CVD in patients with chronic renal failure.

Adult↗