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1.
World J Clin Cases ; 11(33): 7972-7979, 2023 Nov 26.
Article in English | MEDLINE | ID: mdl-38075571

ABSTRACT

BACKGROUND: Acute myelitis (AM) can lead to sudden sensory, motor and autonomic nervous dysfunction, which negatively affects their daily activities and quality of life, so it is necessary to explore optimization from a therapeutic perspective to curb the progression of the disease. AIM: To investigate the effect of ganglioside (GM) combined with methylprednisolone sodium succinate (MPSS) on the curative effect and neurological function of patients with AM. METHODS: First, we selected 108 AM patients visited between September 2019 and September 2022 and grouped them based on treatment modality, with 52 patients receiving gamma globulin (GG) + MPSS and 56 patients receiving GM + MPSS, assigned to the control group (Con) and observation group (Obs), respectively. The therapeutic effect, neurological function (sensory and motor function scores), adverse events (AEs), recovery (time to sphincter function recovery, time to limb muscle strength recovery above grade 2, and time to ambulation), inflammatory factors (IFs) [interleukin (IL)-6, C-reactive protein (CRP), and tumor necrosis factor (TNF)-α] and other data of the two groups were collected for evaluation and comparison. RESULTS: The Obs had: (1) A significantly higher response rate of treatment than the Con; (2) Higher scores of sensory and motor functions after treatment that were higher than the baseline (before treatment) and higher than the Con levels; (3) Lower incidence rates of skin rash, gastrointestinal discomfort, dyslipidemia, osteoporosis and other AEs; (4) Faster posttreatment recovery of sphincter function, limb muscle strength and ambulation; and (5) Markedly lower posttreatment IL-6, CRP and TNF-α levels than the baseline and the Con levels. CONCLUSION: From the above, it can be seen that GM + MPSS is highly effective in treating AM, with a favorable safety profile comparable to that of GG + MPSS. It can significantly improve patients' neurological function, speed up their recovery and inhibit serum IFs.

2.
J Drug Target ; 25(6): 471-484, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28135859

ABSTRACT

This review focuses on recent investigations that used Pluronic P123 (P123) as pharmaceutical ingredients in vesicle, micelle, mixed micelle, in situ gel, tablet and emulsion. The main results from these studies show that P123 can significantly increase the stability of incorporated hydrophobic drugs with enhanced in vitro cytotoxicity and cellular uptake of anticancer drugs. Moreover, modified forms of P123 with RGD, folate or other targeted marker have shown its therapeutic potentials in various types of tumors and cancers. Furthermore, modified forms of P123 alone and/or mixed with other copolymers have less toxic effects and more tumor-specific delivery of anticancer drugs. They are promising materials as a nanoplatform for the drug delivery. Finally, the future perspectives of the field are briefly discussed.


Subject(s)
Antineoplastic Agents/administration & dosage , Drug Delivery Systems , Poloxalene/administration & dosage , Animals , Antineoplastic Agents/adverse effects , Antineoplastic Agents/pharmacology , Drug Carriers/chemistry , Drug Stability , Humans , Hydrophobic and Hydrophilic Interactions , Oligopeptides/administration & dosage , Poloxalene/adverse effects , Poloxalene/chemistry
3.
Clin Biochem ; 46(7-8): 694-7, 2013 May.
Article in English | MEDLINE | ID: mdl-23195138

ABSTRACT

OBJECTIVES: Determinations of cerebrospinal fluid (CSF) lactate and pyruvate concentrations and CSF lactate:pyruvate (L/P) ratios are important in several clinical settings, yet published normative data have significant limitations. We sought to determine a large dataset of stringently-defined normative data for CSF lactate and pyruvate concentrations and CSF L/P ratios. DESIGN AND METHODS: We evaluated data from 627 patients who had determinations of CSF lactate and/or CSF pyruvate from 2001 to 2011 at the Cleveland Clinic. Inclusion in the normal reference population required normal CSF cell counts, glucose and protein and routine serum chemistries and absence of progressive brain disorder, epilepsy, or seizure within 24h. Brain MRI, if done, showed no evidence of tumor, acute changes or basal ganglia abnormality. CSF cytology, CSF alanine and immunoglobulin levels, and oligoclonal band analysis were required to be normal, if done. Various inclusion/exclusion criteria were compared. RESULTS: 92 patients fulfilled inclusion/exclusion criteria for a reference population. The 95% central intervals (2.5%-97.5%) for CSF lactate and pyruvate levels were 1.01-2.09mM and 0.03-0.15mM, respectively, and 9.05-26.37 for CSF L/P. There were no significant gender-related differences of CSF lactate or pyruvate concentrations or of CSF L/P. Weak positive correlations between the concentration of CSF lactate or pyruvate and age were noted. CONCLUSIONS: Using stringent inclusion/exclusion criteria, we determined normative data for CSF lactate and pyruvate concentrations and CSF L/P ratios in a large, well-characterized reference population. Normalcy of routine CSF and blood analytes are the most important parameters in determining reference intervals for CSF lactate and pyruvate.


Subject(s)
Lactic Acid/cerebrospinal fluid , Pyruvic Acid/cerebrospinal fluid , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Infant , Male , Middle Aged , Reference Values
5.
Blood ; 115(24): 5111-20, 2010 Jun 17.
Article in English | MEDLINE | ID: mdl-20228268

ABSTRACT

Factor XII (FXII) and high molecular weight kininogen (HK) mutually block each other's binding to the urokinase plasminogen activator receptor (uPAR). We investigated if FXII stimulates cells by interacting with uPAR. FXII (3-62nM) with 0.05mM Zn(2+) induces extracellular signal-related kinase 1/2 (ERK1/2; mitogen-activated protein kinase 44 [MAPK44] and MAPK42) and Akt (Ser473) phosphorylation in endothelial cells. FXII-induced phosphorylation of ERK1/2 or Akt is a zymogen activity, not an enzymatic event. ERK1/2 or Akt phosphorylation is blocked upstream by PD98059 or Wortmannin or LY294002, respectively. An uPAR signaling region for FXII is on domain 2 adjacent to uPAR's integrin binding site. Cleaved HK or peptides from HK's domain 5 blocks FXII-induced ERK1/2 and Akt phosphorylation. A beta(1) integrin peptide that binds uPAR, antibody 6S6 to beta(1) integrin, or the epidermal growth factor receptor (EGFR) inhibitor AG1478 blocks FXII-induced phosphorylation of ERK1/2 and Akt. FXII induces endothelial cell proliferation and 5-bromo-2'deoxy-uridine incorporation. FXII stimulates aortic sprouting in normal but not uPAR-deficient mouse aorta. FXII produces angiogenesis in matrigel plugs in normal but not uPAR-deficient mice. FXII knockout mice have reduced constitutive and wound-induced blood vessel number. In sum, FXII initiates signaling mediated by uPAR, beta(1) integrin, and the EGFR to induce human umbilical vein endothelial cell proliferation, growth, and angiogenesis.


Subject(s)
ErbB Receptors/metabolism , Factor XII/metabolism , MAP Kinase Signaling System/physiology , Neovascularization, Physiologic/physiology , Proto-Oncogene Proteins c-akt/metabolism , Receptors, Urokinase Plasminogen Activator/metabolism , Animals , Aorta, Thoracic/cytology , Aorta, Thoracic/metabolism , Cell Division/physiology , Cells, Cultured , Endothelial Cells/cytology , Endothelial Cells/metabolism , Enzyme Inhibitors/pharmacology , Factor XII/pharmacology , Humans , Integrins/metabolism , MAP Kinase Signaling System/drug effects , Mice , Mice, Inbred C57BL , Mice, Knockout , Mitogen-Activated Protein Kinase 1/antagonists & inhibitors , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/antagonists & inhibitors , Mitogen-Activated Protein Kinase 3/metabolism , Neovascularization, Physiologic/drug effects , Phosphorylation/drug effects , Phosphorylation/physiology , Umbilical Veins/cytology
6.
J Control Release ; 140(3): 301-5, 2009 Dec 16.
Article in English | MEDLINE | ID: mdl-19508879

ABSTRACT

Previously we reported that plasma kallikrein and high molecular weight kininogen attach to the surface of dextran-coated superparamagnetic iron oxide nanoparticles (SPION) through the incompletely covered iron oxide core (Simberg et al., Biomaterials, 2009). Here we show that SPION also activate kallikrein-kinin system in vitro and in vivo. The serine protease activity of kallikrein was stably associated with SPION and could be detected on the nanoparticles even after extensive washing steps. The enzymatic activity was not detectable in kininogen-deficient and Factor XII-deficient plasma. The enzymatic activation could be blocked by precoating SPION with histidine-rich Domain 5 (D5) of kininogen. Importantly, the kallikrein activity was detectable in plasma of SPION-injected, but not of D5/SPION-injected mice. Tumor-targeted SPION when injected into kininogen-deficient and control mice, produced high levels of vascular clotting in tumors, suggesting that kallikrein activation is not responsible for the nanoparticle-induced thrombosis. These data could help in understanding the toxicity of nanomaterials and could be used in designing nanoparticles with controlled enzymatic activity.


Subject(s)
Ferric Compounds , Kallikrein-Kinin System/physiology , Kallikrein-Kinin System/radiation effects , Animals , Blood Proteins/chemistry , Dextrans , Drug Delivery Systems , Enzyme Activation , Fluorescein-5-isothiocyanate , Fluorescent Dyes , Magnetics , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Molecular Weight , Nanoparticles , Thrombosis/chemically induced
7.
Biomaterials ; 30(23-24): 3926-33, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19394687

ABSTRACT

In order to understand the role of plasma proteins in the rapid liver clearance of dextran-coated superparamagnetic iron oxide (SPIO) in vivo, we analyzed the full repertoire of SPIO-binding blood proteins using novel two-dimensional differential mass spectrometry approach. The identified proteins showed specificity for surface domains of the nanoparticles: mannan-binding lectins bound to the dextran coating, histidine-rich glycoprotein and kininogen bound to the iron oxide part, and the complement lectin and contact clotting factors were secondary binders. Nanoparticle clearance studies in knockout mice suggested that these proteins, as well as several previously identified opsonins, do not play a significant role in the SPIO clearance. However, both the dextran coat and the iron oxide core remained accessible to specific probes after incubation of SPIO in plasma, suggesting that the nanoparticle surface could be available for recognition by macrophages, regardless of protein coating. These data provide guidance to rational design of bioinert, long-circulating nanoparticles.


Subject(s)
Iron/metabolism , Nanoparticles/chemistry , Oxides/metabolism , Proteomics/methods , Animals , Cells, Cultured , Dextrans , Ferrosoferric Oxide , Iron/chemistry , Kupffer Cells/metabolism , Magnetite Nanoparticles , Mice , Oxides/chemistry , Plasma/metabolism , Protein Binding , Proteins/metabolism
8.
Zhong Yao Cai ; 32(11): 1746-8, 2009 Nov.
Article in Chinese | MEDLINE | ID: mdl-20218300

ABSTRACT

OBJECTIVE: To study the optimal extraction process of chaihushugan powder by orthogonal design. METHODS: RP-HPLC method was developed for the determination of saikosaponin a, ferulic acid, hesperidin and paeoniflorin in chaihushugan powder. The contents of the components and the extraction yield were selected as assessment indices. Four factors were study by L9 (3(4)), including the alcohol concentration, amount of alcohol, duration of extraction and times of extraction. RESULTS: The optimal extracting condition was 80% alcohol consumed as 10 times of crude herb amount, and extracting two times for 90 min each time. CONCLUSION: This study supplies theoretical base for the development of chaihushugan powder formulation.


Subject(s)
Bupleurum/chemistry , Drugs, Chinese Herbal/isolation & purification , Oleanolic Acid/analogs & derivatives , Plants, Medicinal/chemistry , Saponins/analysis , Technology, Pharmaceutical/methods , Benzoates/analysis , Benzoates/isolation & purification , Bridged-Ring Compounds/analysis , Bridged-Ring Compounds/isolation & purification , Chromatography, High Pressure Liquid/methods , Coumaric Acids/analysis , Coumaric Acids/isolation & purification , Drug Combinations , Drugs, Chinese Herbal/chemistry , Ethanol/chemistry , Glucosides/analysis , Glucosides/isolation & purification , Hesperidin/analysis , Hesperidin/isolation & purification , Hot Temperature , Monoterpenes , Oleanolic Acid/analysis , Oleanolic Acid/isolation & purification , Powders , Quality Control , Saponins/isolation & purification , Solubility , Time Factors
9.
Blood ; 111(3): 1274-81, 2008 Feb 01.
Article in English | MEDLINE | ID: mdl-18000168

ABSTRACT

High-molecular-weight kininogen (HK) plays an important role in the assembly of the plasma kallikrein-kinin system. While the human genome contains a single copy of the kininogen gene, 3 copies exist in the rat (1 encoding K-kininogen and 2 encoding T-kininogen). Here, we confirm that the mouse genome contains 2 homologous kininogen genes, mKng1 and mKng2, and demonstrate that these genes are expressed in a tissue-specific manner. To determine the roles of these genes in murine development and physiology, we disrupted mKng1, which is expressed primarily in the liver. mKng1(-/-) mice were viable, but lacked plasma HK and low-molecular-weight kininogen (LK), as well as DeltamHK-D5, a novel kininogen isoform that lacks kininogen domain 5. Moreover, despite normal tail vein bleeding times, mKng1(-/-) mice displayed a significantly prolonged time to carotid artery occlusion following Rose Bengal administration and laser-induced arterial injury. These results suggest that a single gene, mKng1, is responsible for production of plasma kininogen, and that plasma HK contributes to induced arterial thrombosis in mice.


Subject(s)
Kininogens/metabolism , Plasma/metabolism , Thrombosis/metabolism , Amino Acid Sequence , Animals , Base Sequence , Bradykinin/blood , Gene Deletion , Genetic Vectors/genetics , Homozygote , Kininogens/chemistry , Kininogens/deficiency , Kininogens/genetics , Mice , Mice, Knockout , Molecular Sequence Data , RNA, Messenger/genetics , Sequence Alignment , Thrombosis/genetics , Time Factors
10.
Zhongguo Dang Dai Er Ke Za Zhi ; 8(6): 467-9, 2006 Dec.
Article in Chinese | MEDLINE | ID: mdl-17178036

ABSTRACT

OBJECTIVE: Nephrotic syndrome (NS) is characterized by marked urinary excretion of albumin and other intermediated-size plasma proteins such as transferrin. The aim of this study was to determine the changes of serum iron and transferrin and the relationship between the serum and urinary transferrin. METHODS: The indexes related to iron metabolism, including serum iron, ferritin, transferrin, total iron-binding capacity, transferrin saturation and hematological parameters (Hb, MCV, MCH), and urinary transferrin were measured in 37 children with NS before treatment and at the remission stage. Thirty-five age-matched healthy children served as controls. RESULTS: Serum iron levels (18.8 +/- 3.8 micromol/L) in NS patients before treatment were significantly lower than in the healthy controls (22.2 +/-3.8 micromol/L) and those measured at the remission stage (21.0 +/- 3.5 micromol/L) (P < 0.01). Serum transferrin levels in NS patients before therapy (1.9 +/- 0.3 g/L) also decreased compared with those in the healthy controls (3.1 +/- 0.5 g/L) and those measured at the remission stage (2.9 +/- 0.6 g/L) (P < 0.01). In contrast, serum total iron-binding capacity and transferrin saturation were noticeably higher in NS patients before treatment than those in the healthy controls (total iron-binding capacity 56.4 +/- 9.2 micromol/L vs 50.7 +/- 6.8 micromol, P < 0.01; transferrin saturation 55.7 +/- 9.2 % vs 46.4 +/- 8.2%, P < 0.01) and were also higher than those measured at the remission stage (51.9 +/-7.7 micromol/L and 47.4 +/- 13.3%) (P < 0.01). Serum transferrin positively correlated to serum albumin (r = 0.609, P < 0.01) and negatively correlated to urinary transferrin (r = -0.550, P < 0.01) in NS patients before treatment. CONCLUSIONS: Serum iron and transferrin levels markedly decreased in NS patients, which may be partially related to the urinary loss of transferrin.


Subject(s)
Iron/blood , Nephrotic Syndrome/blood , Transferrin/analysis , Adolescent , Child , Child, Preschool , Female , Humans , Male , Transferrin/urine
11.
Matrix Biol ; 25(2): 118-29, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16300938

ABSTRACT

Alpha11beta1 integrin is a collagen receptor, which is expressed in a highly regulated manner in a specific subset of ectomesenchymally and mesodermally derived cells. We previously established that a 3 kb region upstream of the transcription start site of the ITGA11 gene efficiently induced alpha11 transcription in a cell-type specific manner. Using the human fibrosarcoma cell line HT1080 and human skin fibroblasts, we now report that the majority of the activity in the proximal promoter resides in a region spanning nt +25 to nt -176. Mutation and deletion analyses using luciferase reporter assays showed that tandem low affinity Sp1/Sp3 binding sites, together with an Ets-1-like binding site, were needed for the proximal promoter activity in mesenchymal cells. EMSAs and supershift assays showed that Sp1 and Sp3 both bind to the Sp1/Sp3 binding sites, whereas occupation of the Ets-1 binding site appears to be Sp3-dependent. Chromatin immunoprecipitation assays verified that Sp1, Sp3 and Ets-1 can bind the promoter in vivo. In heterologous Drosophila SL2 cells, Sp1, Sp3 and Ets-1 all transactivated the alpha11 promoter, with Sp1 being the most efficient activator. The lack of any synergistic effect of Sp1/Sp3 and Ets-1 in SL2 cells indicates that an Ets family member other than Ets-1 might be involved in regulating alpha11 transcription in mesenchymal cells. The central role of Sp1 in regulating alpha11 RNA transcription was further verified by the ability of the Sp1 inhibitor mithramycin A to efficiently attenuate alpha11 RNA and protein levels in primary fibroblasts. The proximal promoter itself was able to confer cell-type specific transcription on HT1080 cells and embryonic fibroblasts but not on U2OS and JAR cells. We speculate that the "mesenchymal signature" of alpha11 integrin gene expression is controlled by the activity of Sp1/Sp3, fibroblast-specific combinations of Ets family members and yet unidentified enhancer-binding transcription factors.


Subject(s)
Integrin alpha Chains/genetics , Mesoderm/physiology , Proto-Oncogene Protein c-ets-1/metabolism , Sp3 Transcription Factor/metabolism , Animals , Base Sequence , Binding Sites , Cell Line , Cell Line, Tumor , Humans , Integrin alpha Chains/chemistry , Integrin alpha Chains/metabolism , Mice , Molecular Sequence Data , Promoter Regions, Genetic , Proto-Oncogene Protein c-ets-1/chemistry
13.
Prostate ; 64(1): 29-39, 2005 Jun 15.
Article in English | MEDLINE | ID: mdl-15651064

ABSTRACT

BACKGROUND: Trypsinogens are pancreatic serine proteinases and expressed in several cancers as tumor-associated trypsinogens (TAT). Trypsin mediates activation of pro-uPA and pro-MMPs, thus promoting angiogenesis and tumor invasion. Recently, we described expression of TAT in the human male genital tract and now we studied TAT in relation to PSA in PCa. METHODS: TAT expression was studied by immunohistochemistry, in situ hybridization, RT-PCR, DNA-sequencing and IFMA. LNCaP cells were used to study secretion of TAT and PSA after androgen stimulation. RESULTS: Immunoreactive TAT was localized in all prostatic tumors (n = 109), lymph node (n = 16), and bone metastases (n = 17). Immunostaining intensity increased with higher Gleason's grade, whereas PSA immunostaining decreased significantly. PSA and TAT were not identically distributed in benign and malignant cells. Androgen stimulation of LNCaP cells decreased secretion of TAT and increased that of PSA. TAT mRNA was demonstrated in tissue sections and identified as TAT-1 and -2 by RT-PCR and DNA-sequencing. CONCLUSIONS: Expression of TAT is better preserved than PSA in high-grade PCa. Expression of TAT and PSA is regulated by different mechanisms as demonstrated in tissue sections and in vitro. Locally produced TAT may act in a paracrine mode to promote angiogenesis and tumor invasion in PCa by both activating and degrading of other proteinases. Further studies on the role of TAT in invasive PCa and on the mechanisms involved in the regulation of TAT expression are warranted.


Subject(s)
Prostatic Neoplasms/physiopathology , Trypsin/genetics , Trypsin/metabolism , Trypsinogen/genetics , Trypsinogen/metabolism , Gene Expression Regulation, Enzymologic , Gene Expression Regulation, Neoplastic , Humans , Immunohistochemistry , In Situ Hybridization , In Vitro Techniques , Male , Metribolone/pharmacology , Oligonucleotide Array Sequence Analysis , Paracrine Communication , Prostate-Specific Antigen/genetics , Prostate-Specific Antigen/metabolism , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/pathology
14.
Zhong Xi Yi Jie He Xue Bao ; 2(2): 135-7, 2004 Mar.
Article in Chinese | MEDLINE | ID: mdl-15339478

ABSTRACT

OBJECTIVE: To determinate the catalpol contents in dried rehmannia root and Taohong Siwu Decoction containing rehmannia root with high performance liquid chromatography (HPLC). METHODS: Catalpol was separated on a YWG-C18 column using water-acetonitrile (99.4:0.6) as mobile phase and detective wavelength at 210 nm. RESULTS: The linear curve of tested catalpol concentration within the range of 0.0536-5.3600 microg/microl was ideal (n=5, r=0.999 7). The average recovery rate of the dried rehmannia root and Taohong Siwu decoction was 98.7% (RSD=0.48%) and 98.2% (RSD=1.29%) respectively. CONCLUSION: HPLC method is accurate and valuable for the quality control of Radix Rehmanniae and Taohong Siwu Decoction.


Subject(s)
Glucosides/analysis , Iridoids/analysis , Medicine, Chinese Traditional , Rehmannia/chemistry , Chromatography, High Pressure Liquid , Iridoid Glucosides
16.
Clin Chem ; 49(1): 97-103, 2003 Jan.
Article in English | MEDLINE | ID: mdl-12507965

ABSTRACT

BACKGROUND: A major portion of prostate-specific antigen exists in circulation as a complex with alpha(1)-antichymotrypsin (PSA-ACT), whereas a minor part is free (fPSA). The proportion of PSA-ACT is increased in prostate cancer (PCa), but immunologic determination of PSA-ACT is hampered by a background produced by nonspecific adsorption of ACT to the solid phase. To reduce the nonspecific interference, we produced an antibody specific for complexed ACT and developed immunofluorometric assays (IFMAs) for simultaneous measurement of fPSA + PSA-ACT (fPSA/PSA-ACT) and PSA-ACT + total PSA (tPSA, PSA-ACT/tPSA). METHODS: Monoclonal antibodies (MAbs) were produced by immunization with PSA-ACT. The dual-label time-resolved IFMAs for fPSA/PSA-ACT and PSA-ACT/tPSA used a capture MAb to tPSA, an Eu(3+)-labeled MAb to fPSA or complexed ACT, and an Sm(3+)-labeled MAb to complexed ACT or to tPSA as tracer antibodies. The clinical utility was evaluated using serum samples from individuals with or without PCa with PSA concentrations of 2.0-20.0 micro g/L. RESULTS: One MAb (1D10) showed low cross-reactivity with free ACT and cathepsin G-ACT. A sandwich assay for PSA-ACT with 1D10 as tracer had a detection limit of 0.05 micro g/L, and with this assay, PSA-ACT was undetectable in female sera. The detection limit for fPSA was 0.004 micro g/L. Determinations of the ratio of fPSA to PSA-ACT and the proportions of fPSA/tPSA and PSA-ACT/tPSA provided the same clinical specificity for PCa and provided significantly better clinical specificity than did tPSA. CONCLUSIONS: Background problems observed in earlier PSA-ACT assays are eliminated by the use of a MAb specific for complexed ACT as a tracer. The same clinical validity can be obtained by determination of fPSA or PSA-ACT together or in combination with tPSA.


Subject(s)
Prostate-Specific Antigen/blood , alpha 1-Antichymotrypsin/blood , Aged , Animals , Antibodies, Monoclonal/isolation & purification , False Positive Reactions , Female , Fluoroimmunoassay , Humans , Male , Mice , Mice, Inbred BALB C , Middle Aged , Prostatic Hyperplasia/diagnosis , Prostatic Neoplasms/diagnosis , Protein Binding , ROC Curve , Reproducibility of Results , Sensitivity and Specificity
17.
J Biol Chem ; 278(9): 7270-7, 2003 Feb 28.
Article in English | MEDLINE | ID: mdl-12496264

ABSTRACT

The integrins alpha(1)beta(1), alpha(2)beta(1), alpha(10)beta(1), and alpha(11)beta(1) are referred to as a collagen receptor subgroup of the integrin family. Recently, both alpha(1)beta(1) and alpha(2)beta(1) integrins have been shown to recognize triple-helical GFOGER (where single letter amino acid nomenclature is used, O = hydroxyproline) or GFOGER-like motifs found in collagens, despite their distinct binding specificity for various collagen subtypes. In the present study we have investigated the mechanism whereby the latest member in the integrin family, alpha(11)beta(1), recognizes collagens using C2C12 cells transfected with alpha(11) cDNA and the bacterially expressed recombinant alpha(11) I domain. The ligand binding properties of alpha(11)beta(1) were compared with those of alpha(2)beta(1). Mg(2+)-dependent alpha(11)beta(1) binding to type I collagen required micromolar Ca(2+) but was inhibited by 1 mm Ca(2+), whereas alpha(2)beta(1)-mediated binding was refractory to millimolar concentrations of Ca(2+). The bacterially expressed recombinant alpha(11) I domain preference for fibrillar collagens over collagens IV and VI was the same as the alpha(2) I domain. Despite the difference in Ca(2+) sensitivity, alpha(11)beta(1)-expressing cells and the alpha(11) I domain bound to helical GFOGER sequences in a manner similar to alpha(2)beta(1)-expressing cells and the alpha(2) I domain. Modeling of the alpha I domain-collagen peptide complexes could partially explain the observed preference of different I domains for certain GFOGER sequence variations. In summary, our data indicate that the GFOGER sequence in fibrillar collagens is a common recognition motif used by alpha(1)beta(1), alpha(2)beta(1), and also alpha(11)beta(1) integrins. Although alpha(10) and alpha(11) chains show the highest sequence identity, alpha(2) and alpha(11) are more similar with regard to collagen specificity. Future studies will reveal whether alpha(2)beta(1) and alpha(11)beta(1) integrins also show overlapping biological functions.


Subject(s)
Collagen/chemistry , Collagen/metabolism , Integrins/chemistry , Integrins/metabolism , Receptors, Collagen/chemistry , Receptors, Collagen/metabolism , Amino Acid Motifs , Animals , Calcium/metabolism , Cell Adhesion , Cells, Cultured , DNA, Complementary/metabolism , Dose-Response Relationship, Drug , Humans , Kinetics , Magnesium/metabolism , Mice , Models, Molecular , Peptides/chemistry , Phenylalanine/chemistry , Precipitin Tests , Protein Binding , Protein Structure, Tertiary , Recombinant Proteins/metabolism
18.
Matrix Biol ; 21(6): 513-23, 2002 Oct.
Article in English | MEDLINE | ID: mdl-12392762

ABSTRACT

Integrin alpha11beta1 is a collagen receptor which is expressed in a subset of mesenchymally-derived tissues during embryogenesis. Based on available human chromosome 15-derived sequences and genomic PCR, the complete exon structure of ITGA11, including the proximal promoter, was assembled into 30 exons. The inserted region (encoding amino acids 804-826) distinguishing alpha11 from other integrin alpha chains, was placed in the very beginning of exon 20. PCR data failed to show alternative splicing of RNA transcribed from this region. Using the oligo-capping technique a major transcription start site was mapped 30 nucleotides upstream of the translation start and identified as an abbreviated initiator sequence. Promoter sequence analysis in silico suggested the presence of multiple binding sites for transcription factors in the region upstream of the transcription start. 3 kb of the 5' flanking sequence was isolated and used to generate luciferase promoter constructs. In the fibrosarcoma cell line HT1080 a core promoter [nt (-)127-(+)25], a potential silencer region [nt (-)400-(-)127] and a potential enhancer region [nt (-)1519-(-)400], were identified as being important for alpha11 transcription in mesenchymal cells. Furthermore, studies of the promoter region will provide valuable information regarding the molecular mechanisms underlying the cell- and tissue- specific expression pattern of ITGA11.


Subject(s)
Integrin alpha Chains/genetics , Promoter Regions, Genetic/genetics , Alternative Splicing , Base Sequence/genetics , Cloning, Molecular , Exons/genetics , Humans , Molecular Sequence Data , Transcription Initiation Site , Tumor Cells, Cultured
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