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1.
J Intern Med ; 285(1): 49-58, 2019 01.
Article in English | MEDLINE | ID: mdl-30028049

ABSTRACT

OBJECTIVE: IgG antibodies against apolipoprotein A-I (ApoA-I) have been found to be elevated in subjects from the general population with clinically manifest cardiovascular disease and in myocardial infarction patients with an adverse prognosis. Here, we investigated whether these antibodies are prospectively associated with carotid artery disease progression and with the risk for first-time cardiovascular events in individuals with no previous history of cardiovascular disease. APPROACH AND RESULTS: We selected 383 subjects from the cardiovascular cohort of Malmö Diet and Cancer study who suffered a coronary event during a median follow-up period of 15.4 (10.3-16.4) years and 395 age- and sex-matched controls. None of the study participants had a previous history of coronary artery disease or stroke. Anti-ApoA-I IgG were measured by ELISA in serum samples collected at baseline. Intima-media thickness (IMT) was measured in the common carotid artery and in the carotid bifurcation at baseline and after 15.9 (±1.5) years. We found no associations between anti-ApoA-I IgG and carotid artery IMT at baseline or with IMT progression during follow-up. In Cox proportional hazards analyses adjusted for traditional cardiovascular risk factors, the hazard ratio (HR 95%CI) for the primary outcome, incident coronary events, was 0.97 (0.75-1.25), P = 0.782, in subjects with anti-ApoA-I IgG within the highest tertile compared with the lowest tertile. Similarly, we did not find any associations with the secondary outcome, incident first-time stroke. CONCLUSIONS: Serum autoantibodies against ApoA-I do not correlate with disease progression and adverse events in cardiovascular disease-free individuals from the general population.


Subject(s)
Apolipoprotein A-I/immunology , Cardiovascular Diseases/immunology , Carotid Artery Diseases/immunology , Immunoglobulin G/immunology , Biomarkers/blood , Cardiovascular Diseases/diagnostic imaging , Carotid Artery Diseases/diagnostic imaging , Carotid Intima-Media Thickness , Case-Control Studies , Disease Progression , Female , Humans , Male , Middle Aged , Prospective Studies , Risk Factors , Sweden , Ultrasonography
3.
Indoor Air ; 26(5): 743-54, 2016 10.
Article in English | MEDLINE | ID: mdl-26451694

ABSTRACT

Upper airway irritation is common among individuals working in moldy and damp buildings. The aim of this study was to investigate effects on the protein composition of the nasal lining fluid. The prevalence of symptoms in relation to work environment was examined in 37 individuals working in two damp buildings. Microbial growth was confirmed in one of the buildings. Nasal lavage fluid was collected from 29 of the exposed subjects and 13 controls, not working in a damp building. Protein profiles were investigated with a proteomic approach and evaluated by multivariate statistical models. Subjects from both workplaces reported upper airway and ocular symptoms. Based on protein profiles, symptomatic subjects in the two workplaces were discriminated from each other and separated from healthy controls. The groups differed in proteins involved in inflammation and host defense. Measurements of innate immunity proteins showed a significant increase in protein S100-A8 and decrease in SPLUNC1 in subjects from one workplace, while alpha-1-antitrypsin was elevated in subjects from the other workplace, compared with healthy controls. The results show that protein profiles in nasal lavage fluid can be used to monitor airway mucosal effects in personnel working in damp buildings and indicate that the profile may be separated when the dampness is associated with the presence of molds.


Subject(s)
Nasal Lavage Fluid/chemistry , Occupational Diseases/metabolism , Occupational Exposure/analysis , Respiratory Tract Diseases/metabolism , Sick Building Syndrome/metabolism , Adult , Air Pollution, Indoor/adverse effects , Biomarkers/metabolism , Calgranulin A/analysis , Case-Control Studies , Cross-Sectional Studies , Female , Fungi/growth & development , Glycoproteins/analysis , Humans , Humidity , Male , Middle Aged , Multivariate Analysis , Occupational Diseases/etiology , Phosphoproteins/analysis , Proteomics , Respiratory Tract Diseases/etiology , Sick Building Syndrome/etiology , alpha 1-Antitrypsin/analysis
4.
J Pharmacol Exp Ther ; 339(1): 313-20, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21791628

ABSTRACT

N-{[5-(methanesulfonyl)pyridin-2-yl]methyl}-6-methyl-5-(1-methyl-1H-pyrazol-5-yl)-2-oxo-1-[3-(trifluoromethyl)phenyl]-1,2-dihydropyridine-3-carboxamide (AZD9668) is a novel, oral inhibitor of neutrophil elastase (NE), an enzyme implicated in the signs, symptoms, and disease progression in NE-driven respiratory diseases such as bronchiectasis and chronic obstructive pulmonary disease via its role in the inflammatory process, mucus overproduction, and lung tissue damage. In vitro and in vivo experiments were done to evaluate the binding kinetics, potency, and selectivity of AZD9668, its effects in whole-blood and cell-based assays, and its efficacy in models of lung inflammation and damage. In contrast to earlier NE inhibitors, the interaction between AZD9668 and NE was rapidly reversible. AZD9668 was also highly selective for NE over other neutrophil-derived serine proteases. In cell-based assays, AZD9668 inhibited plasma NE activity in zymosan-stimulated whole blood. In isolated human polymorphonuclear cells, AZD9668 inhibited NE activity on the surface of stimulated cells and in the supernatant of primed, stimulated cells. AZD9668 showed good crossover potency to NE from other species. Oral administration of AZD9668 to mice or rats prevented human NE-induced lung injury, measured by lung hemorrhage, and an increase in matrix protein degradation products in bronchoalveolar lavage (BAL) fluid. In an acute smoke model, AZD9668 reduced the inflammatory response to cigarette smoke as indicated by a reduction in BAL neutrophils and interleukin-1ß. Finally, AZD9668 prevented airspace enlargement and small airway wall remodeling in guinea pigs in response to chronic tobacco smoke exposure whether dosed therapeutically or prophylactically. In summary, AZD9668 has the potential to reduce lung inflammation and the associated structural and functional changes in human diseases.


Subject(s)
Leukocyte Elastase/antagonists & inhibitors , Pyridones/pharmacology , Serine Proteinase Inhibitors , Sulfones/pharmacology , Acute Lung Injury/chemically induced , Acute Lung Injury/drug therapy , Animals , Bronchoalveolar Lavage Fluid/cytology , Dogs , Dose-Response Relationship, Drug , Emphysema/chemically induced , Emphysema/pathology , Female , Glycine/analogs & derivatives , Glycine/pharmacology , Guinea Pigs , Humans , Kinetics , Mice , Mice, Inbred BALB C , Oxadiazoles/pharmacology , Pneumonia/drug therapy , Protein Binding , Pyrimidinones/pharmacology , Rats , Species Specificity , Substrate Specificity , Sulfonamides/pharmacology , Swine , Tobacco Smoke Pollution/adverse effects
5.
J Intern Med ; 269(3): 306-21, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21205019

ABSTRACT

OBJECTIVES: Exchangeable low-density lipoprotein (LDL)-associated proteins can affect the atherogenic properties of LDL. Our aim was to analyse the protein composition of LDL from individuals with or without type 2 diabetes and the metabolic syndrome (T2DM) in relation to other LDL particle characteristics, to assess whether certain proteins associate more with certain subclasses of LDL typical for T2DM, such as small, apoCIII-rich LDL. DESIGN: Low-density lipoprotein from two cohorts of 61-year-old men (n = 19 and 64) with or without T2DM was isolated using size-exclusion chromatography or deuterium oxide-based ultracentrifugation. LDL-associated proteins were identified using mass spectrometry and quantified using two-dimensional gel electrophoresis or enzyme-linked immunosorbent assay. Differently expressed LDL-associated proteins apolipoprotein (apo)J and lysozyme were also measured in serum from a third cohort of women (n = 71) with or without T2DM. Lysozyme binding to advanced glycation end product (AGE)-LDL was examined in vitro. RESULTS: ApoJ and lysozyme were increased in LDL particles with increased apoCIII content and decreased cholesterol content. When isolated with size-exclusion chromatography, LDL from individuals with T2DM contained more apoJ and lysozyme and less apoA1 than LDL from control individuals. LDL content of apoJ correlated with a smaller LDL particle size. Serum levels of lysozyme, but not apoJ, were increased in individuals with T2DM. In vitro, lysozyme associated more with AGE-LDL than with unmodified LDL. CONCLUSIONS: Our results indicate that apoJ and lysozyme are increased in LDL with characteristics of small dense LDL in T2DM. Small dense LDL is easily glycated, and the increased affinity of lysozyme for AGE-LDL provides a possible partial explanation for an increase lysozyme in LDL from those with type 2 diabetes.


Subject(s)
Clusterin/blood , Diabetes Mellitus, Type 2/blood , Lipoproteins, LDL/blood , Metabolic Syndrome/blood , Muramidase/blood , Cholesterol/blood , Chromatography, Gel/methods , Cohort Studies , Electrophoresis, Gel, Two-Dimensional/methods , Female , Glycation End Products, Advanced/metabolism , Humans , Male , Middle Aged
6.
J Intern Med ; 263(5): 558-71, 2008 May.
Article in English | MEDLINE | ID: mdl-18248365

ABSTRACT

OBJECTIVE: Several studies support an association between periodontal disease and atherosclerosis with a crucial role for the pathogen Porphyromonas gingivalis. This study aims at investigating the proteolytic and oxidative activity of P. gingivalis on LDL in a whole blood system using a proteomic approach and analysing the effects of P. gingivalis-modified LDL on cell proliferation. METHODS: The cellular effects of P. gingivalis in human whole blood were assessed using lumi-aggregometry analysing reactive oxygen species production and aggregation. Blood was incubated for 30 min with P. gingivalis, whereafter LDL was isolated and a proteomic approach was applied to examine protein expression. LDL-oxidation was determined by analysing the formation of protein carbonyls. The effects of P. gingivalis-modified LDL on fibroblast proliferation were studied using the MTS assay. RESULTS: Incubation of whole blood with P. gingivalis caused an extensive aggregation and ROS production, indicating platelet and leucocyte activation. LDL prepared from bacteria-exposed blood showed an increased protein oxidation, elevated levels of apoM and formation of two apoB-100 N-terminal fragments. Porphyromonas gingivalis-modified LDL markedly increased the growth of fibroblasts. Inhibition of gingipain R suppressed the modification of LDL by P. gingivalis. CONCLUSIONS: The ability of P. gingivalis to change the protein expression and proliferative capacity of LDL may represent a crucial event in periodontitis-associated atherosclerosis.


Subject(s)
Apolipoprotein B-100/metabolism , Lipoproteins, LDL/metabolism , Porphyromonas gingivalis/enzymology , Apolipoproteins/metabolism , Cell Proliferation , Fibroblasts/metabolism , Humans , Protein Carbonylation , Proteomics/methods , Reactive Oxygen Species/blood
7.
J Proteome Res ; 5(2): 330-8, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16457599

ABSTRACT

A comparative proteomic approach was applied to examine nasal lavage fluid (NLF) from patients with seasonal allergic rhinitis (SAR, n = 6) and healthy subjects (controls, n = 5). NLF samples were taken both before allergy (pollen) season and during season, and proteins were analyzed by two-dimensional gel electrophoresis (2-DE) and matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) after tryptic cleavage. Twenty proteins were selected and quantified. During allergy season, the levels of six sialylated isoforms of PLUNC (palate lung nasal epithelial clone) were lower in SAR patients than controls, as were the levels of six isoforms of von Ebner's gland protein (VEGP), including a previously undescribed form with N-linked glycosylation, and of cystatin S. PLUNC is a new innate immunity protein and VEGP and cystatin S are two endogenous proteinase inhibitors. By contrast, the levels of an acidic form of alpha-1-antitrypsin were higher in SAR patients than controls. One previously unidentified NLF protein was found in all samples from the SAR patients during allergy season but not in any sample before allergy season: this protein was identified as eosinophil lysophospholipase (Charcot-Leyden crystal protein/galactin 10). MS/MS analysis of the N-terminus of the protein showed removal of Met and acetylation of Ser. Altogether, these findings illustrate the potential use of proteomics for identifying protein changes associated with allergic rhinitis and for revealing post-translational modifications of such new potential markers of allergic inflammation.


Subject(s)
Nasal Lavage Fluid/chemistry , Proteomics , Rhinitis, Allergic, Seasonal/metabolism , Amino Acid Sequence , Electrophoresis, Gel, Two-Dimensional , Humans , Molecular Sequence Data , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
8.
Biochem Soc Trans ; 31(Pt 4): 810-4, 2003 Aug.
Article in English | MEDLINE | ID: mdl-12887311

ABSTRACT

PLUNC (palate, lung and nasal epithelial clone) is a newly discovered gene that is expressed in the upper respiratory tract and is suggested to be of importance in host defence against bacteria. We have identified two forms of the PLUNC protein in human nasal lavage fluid (NLF) using two-dimensional gel electrophoresis (2-DE) and MS. The apparent molecular masses and isoelectric points of these forms are 24.8 kDa/pI 5.4 and 25.1 kDa/pI 5.5. Notably, the 24.8 kDa/pI 5.4 form of PLUNC is an abundant protein in the 2-DE protein patterns of NLF from healthy subjects. Decreased levels of PLUNC were found in NLF from smokers and workers exposed to reactive epoxy chemicals, indicating that long-term exposure to airway irritants impairs the production of PLUNC in the upper respiratory tract. We have also investigated the presence of lipopolysaccharide (LPS)-binding proteins in NLF. Five proteins were found to adsorb to a LPS-coated surface; two of these proteins correspond to the two PLUNC forms, as judged by 2-DE pattern matching. For comparison, human saliva was found to contain a set of LPS-binding proteins with similar 2-DE spot positions (the same pIs but somewhat lower apparent molecular masses of approximately 20 kDa). These results indicate that PLUNC may be a new marker of airway inflammation and may play a part in the innate immune response, and that human saliva contains yet other members of the family of LPS-binding proteins.


Subject(s)
Acute-Phase Proteins , Glycoproteins/metabolism , Membrane Glycoproteins , Nasal Lavage Fluid/chemistry , Phosphoproteins/metabolism , Amino Acid Sequence , Carrier Proteins/analysis , Electrophoresis, Gel, Two-Dimensional , Glycoproteins/analysis , Glycoproteins/genetics , Humans , Irritants/pharmacology , Phosphoproteins/analysis , Phosphoproteins/genetics , Saliva/chemistry , Sequence Analysis, Protein
9.
Eur Respir J ; 18(1): 130-8, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11510783

ABSTRACT

Phospholipase A2 (PLA2) is a family of enzymes thought to play a key role in inflammation by releasing arachidonic acid for the synthesis of eicosanoids and lysophospholipid for the synthesis of platelet-activating factor. However, the precise contribution of different PLA2 types to the formation of inflammatory lipid mediators in the upper airways is not known and the expression of different PLA2 genes in the human nasal mucosa has not been examined. This study therefore investigated the occurrence of messenger ribonucleic acids (mRNAs) for different PLA2 forms (IB, IIA, IID, IIE, III, IVA, IVB, IVC, V, VI, VII, X, acid calcium-independent (aiPLA2), and calcium-independent membrane bound PLA2, (iPLA2-2)) in the nasal mucosa of five healthy human subjects. Using reversed transcription-polymerase chain reaction (RT-PCR) techniques it was found that all these PLA2 types except PLA2 V were expressed in all subjects, whereas PLA2 V was detected in only one individual on one single occasion. The relative abundance of the different PLA2 transcripts were aiPLA2 > X approximately = IVA > IIA approximately = IIE approximately = IVB approximately = VI > IB approximately = IID approximately = III approximately = IVC approximately = VII approximately = iPLA2-2. To further quantify the mRNA-expression of PLA2 X, IVA and IIA, the samples were reanalysed with a quantitative PCR-technique utilizing competitive deoxyribonucleic acid (DNA) mimics as references. The amounts of PLA2 X, IVA and IIA mRNA were then estimated to 0.9 +/- 0.2, 1.1 +/- 0.7, and 0.0025 +/- 0.0021 amol (mean +/- SE), respectively, confirming the relative abundance of these PLA2 transcripts and indicating that the recently described PLA2 X form is relatively strongly expressed. These findings demonstrate that a large number of PLA2 types are expressed in the normal human nasal mucosa. Moreover, this investigation demonstrates, for the first time, the presence of the newly discovered phospholipase A2 forms IID, IIE, III, IVB, IVC, X and calcium-independent membrane bound phospholipase A2 in the human nasal mucosa and raises the possibility that one or several of these may be involved in inflammatory reactions in the nose.


Subject(s)
Nasal Mucosa/enzymology , Phospholipases A/genetics , Adult , Cells, Cultured , Female , Gene Expression Regulation, Enzymologic/physiology , Humans , Male , Middle Aged , Phospholipases A2 , RNA, Messenger/genetics , Reference Values , Reverse Transcriptase Polymerase Chain Reaction
10.
Electrophoresis ; 22(9): 1795-800, 2001 May.
Article in English | MEDLINE | ID: mdl-11425234

ABSTRACT

We have analyzed protein patterns of human nasal lavage fluid (NLF) with two-dimensional gel electrophoresis (2-DE) and identified several proteins (such as transthyretin, Clara Cell protein 16, lipocalin-1, cystatin S, cystatin SN, immunoglobulin binding factor, statherin, calgranulin B, prolactin-inducible protein, and zinc-alpha2-glycoprotein) by N-terminal amino acid sequencing and matrix-assisted laser desorption/ionizationtime of flight (MALDI-TOF) mass spectrometry. To investigate whether airway irritation causes alterations in NLF 2-DE patterns, we compared epoxy workers with airway irritation (n=8) and healthy controls (n=6) before and after 2 h exposure to the epoxy chemical, dimethylbenzylamine (DMBA, 100 microg/m3) in an exposure chamber. A 25 kDa protein with pI 5.5 was found to be altered in the NLF 2-DE patterns; a trypsin digest of the 2-DE spot analyzed by MALDI-TOF and expressed sequence tags (ESTs) determined after post-source decay (PSD) identified the protein as palate lung and nasal epithelial clone (PLUNC). In controls, the levels of NLF-PLUNC were generally lower after 2 h exposure, whereas in epoxy workers, the levels were increased three- to twentyfold after exposure. The human gene sequence for PLUNC was just recently reported and so far no biofunctional data are available. Our results suggest that PLUNC is involved in the airway inflammatory response after exposure to irritants.


Subject(s)
Epithelial Cells/metabolism , Proteins/analysis , Respiratory System/metabolism , Amino Acid Sequence , Biomarkers , Electrophoresis, Gel, Two-Dimensional , Epithelial Cells/pathology , Humans , Molecular Sequence Data , Proteins/metabolism , Respiratory System/physiopathology , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
11.
Ultramicroscopy ; 87(4): 165-75, 2001 May.
Article in English | MEDLINE | ID: mdl-11334164

ABSTRACT

A central problem of 3D reconstruction in single-particle electron microscopy is the determination of relative orientations of the individual projections contributing to the reconstruction. This article describes an implementation of the method of common lines correlation in Fourier space that allows generation of common lines between an arbitrary number of projections which might posses an arbitrary point group symmetry. Based on this method, it is possible to optimize rotational and translational alignment parameters for individual single-particle projections. The underlying philosophy and details of implementation are discussed, and as an illustration a 3D reconstruction in ice of peroxisomal alcohol oxidase from Pichia pastoris, an octameric assembly with 422-symmetry and a molecular weight of 592 kDa is presented.


Subject(s)
Microscopy, Electron/methods , Alcohol Oxidoreductases/ultrastructure , Fourier Analysis , Fungal Proteins/ultrastructure , Image Processing, Computer-Assisted , Peroxisomes/enzymology , Pichia/enzymology , Pichia/ultrastructure
12.
J Biol Chem ; 276(12): 9344-51, 2001 Mar 23.
Article in English | MEDLINE | ID: mdl-11116144

ABSTRACT

Glial cell line-derived neurotrophic factor (GDNF) family ligands signal through receptor complex consisting of a glycosylphosphatidylinositol-linked GDNF family receptor (GFR) alpha subunit and the transmembrane receptor tyrosine kinase RET. The inherited cancer syndrome multiple endocrine neoplasia type 2 (MEN2), associated with different mutations in RET, is characterized by medullary thyroid carcinoma. GDNF signals via GFRalpha1, neurturin via GFRalpha2, artemin via GFRalpha3, whereas the mammalian GFRalpha receptor for persephin (PSPN) is unknown. Here we characterize the human GFRalpha4 as the ligand-binding subunit required together with RET for PSPN signaling. Human and mouse GFRalpha4 lack the first Cys-rich domain characteristic of other GFRalpha receptors. Unlabeled PSPN displaces (125)I-PSPN from GFRA4-transfected cells, which express endogenous Ret. PSPN can be specifically cross-linked to mammalian GFRalpha4 and Ret, and is able to promote autophosphorylation of Ret in GFRA4-transfected cells. PSPN, but not other GDNF family ligands, promotes the survival of cultured sympathetic neurons microinjected with GFRA4. We identified different splice forms of human GFRA4 mRNA encoding for two glycosylphosphatidylinositol-linked and one putative soluble isoform that were predominantly expressed in the thyroid gland. Overlapping expression of RET and GFRA4 but not other GFRA mRNAs in normal and malignant thyroid medullary cells suggests that GFRalpha4 may restrict the MEN2 syndrome to these cells.


Subject(s)
Drosophila Proteins , Nerve Growth Factors , Nerve Tissue Proteins/metabolism , Proto-Oncogene Proteins/metabolism , Receptor Protein-Tyrosine Kinases/metabolism , Thyroid Neoplasms/metabolism , Animals , Base Sequence , Cell Survival/physiology , DNA Primers , Gene Expression Regulation, Neoplastic , Glial Cell Line-Derived Neurotrophic Factor , Glial Cell Line-Derived Neurotrophic Factor Receptors , Humans , Mice , Molecular Sequence Data , Nerve Tissue Proteins/physiology , Neurons/cytology , Neurons/metabolism , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins c-ret , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptor Protein-Tyrosine Kinases/genetics , Reverse Transcriptase Polymerase Chain Reaction , Thyroid Neoplasms/pathology
13.
Biochim Biophys Acta ; 1459(1): 230-8, 2000 Jul 20.
Article in English | MEDLINE | ID: mdl-10924914

ABSTRACT

Mitochondrial proton-translocating NADH-dehydrogenase (complex I) is one of the largest and most complicated membrane bound protein complexes. Despite its central role in eukaryotic oxidative phosphorylation and its involvement in a broad range of human disorders, little is known about its structure and function. Therefore, we have started to use the powerful genetic tools available for the strictly aerobic yeast Yarrowia lipolytica to study this respiratory chain enzyme. To establish Y. lipolytica as a model system for complex I, we purified and characterized the multisubunit enzyme from Y lipolytica and sequenced the nuclear genes coding for the seven central subunits of its peripheral part. Complex I from Y lipolytica is quite stable and could be isolated in a highly pure and monodisperse state. One binuclear and four tetranuclear iron-sulfur clusters, including N5, which was previously known only from mammalian mitochondria, were detected by EPR spectroscopy. Initial structural analysis by single particle electron microscopy in negative stain and ice shows complex I from Y. lipolytica as an L-shaped particle that does not exhibit a thin stalk between the peripheral and the membrane parts that has been observed in other systems.


Subject(s)
Genes, Fungal , NADH, NADPH Oxidoreductases/chemistry , Protons , Yeasts/enzymology , Yeasts/genetics , Amino Acid Sequence , Biological Transport , Cloning, Molecular , Cold Temperature , Electron Spin Resonance Spectroscopy , Electron Transport Complex I , Microscopy, Electron , Mitochondria/enzymology , Molecular Sequence Data , NADH, NADPH Oxidoreductases/genetics , NADH, NADPH Oxidoreductases/isolation & purification , Polymerase Chain Reaction
14.
Mol Cell Neurosci ; 15(6): 522-33, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10860579

ABSTRACT

Members of the GDNF protein family signal through receptors consisting of a GPI-linked GFRalpha subunit and the transmembrane tyrosine kinase Ret. Here we characterize the mouse Gfra4 and show that it undergoes developmentally regulated alternative splicing in several tissues. The mammalian GFRalpha4 receptor lacks the first Cys-rich domain characteristic of other GFRalpha receptors. Gfra4 is expressed in many tissues, including nervous system, in which intron retention leads to a putative intracellular or secreted GFRalpha4 protein. Efficient splicing occurs only in thyroid, parathyroid, and pituitary and less in adrenal glands. A splice form that leads to a GPI-linked GFRalpha4 receptor is expressed in juvenile thyroid and parathyroid glands. In newborn and mature thyroid as well as in parathyroid and pituitary glands major transcripts encode for a putative transmembrane isoform of GFRalpha4. Significant loss of thyroid C cells in Ret-deficient mice suggests that C cells and cells in adrenal medulla, which also express Ret, may require signaling via the GFRalpha4-Ret receptor. Finally, in human, GFRalpha4 expression may restrict the inherited cancer syndrome multiple endocrine neoplasia type 2, associated with mutations in RET, to these cells.


Subject(s)
Alternative Splicing/physiology , Drosophila Proteins , Gene Expression Regulation, Developmental , Nerve Tissue Proteins/genetics , Neurosecretory Systems/cytology , Proto-Oncogene Proteins/genetics , Receptor Protein-Tyrosine Kinases/genetics , Adrenal Medulla/metabolism , Animals , Cloning, Molecular , Cysteine , Exons , Glial Cell Line-Derived Neurotrophic Factor Receptors , In Situ Hybridization , Mice , Mice, Knockout , Molecular Sequence Data , Nerve Tissue Proteins/chemistry , Nerve Tissue Proteins/metabolism , Neurosecretory Systems/growth & development , Protein Structure, Tertiary , Proto-Oncogene Proteins/chemistry , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins c-ret , RNA, Messenger/analysis , Receptor Protein-Tyrosine Kinases/chemistry , Receptor Protein-Tyrosine Kinases/metabolism , Sequence Homology, Amino Acid , Signal Transduction/physiology , Thyroid Gland/cytology , Thyroid Gland/metabolism
15.
Plant Cell ; 12(3): 419-31, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10715327

ABSTRACT

The photosystem II reaction center D1 protein is known to turn over frequently. This protein is prone to irreversible damage caused by reactive oxygen species that are formed in the light; the damaged, nonfunctional D1 protein is degraded and replaced by a new copy. However, the proteases responsible for D1 protein degradation remain unknown. In this study, we investigate the possible role of the FtsH protease, an ATP-dependent zinc metalloprotease, during this process. The primary light-induced cleavage product of the D1 protein, a 23-kD fragment, was found to be degraded in isolated thylakoids in the dark during a process dependent on ATP hydrolysis and divalent metal ions, suggesting the involvement of FtsH. Purified FtsH degraded the 23-kD D1 fragment present in isolated photosystem II core complexes, as well as that in thylakoid membranes depleted of endogenous FtsH. In this study, we definitively identify the chloroplast protease acting on the D1 protein during its light-induced turnover. Unlike previously identified membrane-bound substrates for FtsH in bacteria and mitochondria, the 23-kD D1 fragment represents a novel class of FtsH substrate-functionally assembled proteins that have undergone irreversible photooxidative damage and cleavage.


Subject(s)
Membrane Proteins/metabolism , Metalloendopeptidases/metabolism , Photosynthetic Reaction Center Complex Proteins/metabolism , Thylakoids/enzymology , ATP-Dependent Proteases , Adenosine Triphosphate/metabolism , Adenosine Triphosphate/pharmacology , Arabidopsis/drug effects , Arabidopsis/enzymology , Arabidopsis Proteins , Caseins/metabolism , Catalytic Domain , Cations/pharmacology , Escherichia coli/genetics , Gene Expression Regulation, Enzymologic , Glutathione Transferase/genetics , Glutathione Transferase/metabolism , Light , Membrane Proteins/genetics , Membrane Proteins/physiology , Metalloendopeptidases/genetics , Metalloendopeptidases/physiology , Photosynthetic Reaction Center Complex Proteins/radiation effects , Photosystem II Protein Complex , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Recombinant Proteins/metabolism , Thylakoids/drug effects
16.
Science ; 287(5457): 1489-93, 2000 Feb 25.
Article in English | MEDLINE | ID: mdl-10688798

ABSTRACT

The molecular control of self-renewal and differentiation of stem cells has remained enigmatic. Transgenic loss-of-function and overexpression models now show that the dosage of glial cell line-derived neurotrophic factor (GDNF), produced by Sertoli cells, regulates cell fate decisions of undifferentiated spermatogonial cells that include the stem cells for spermatogenesis. Gene-targeted mice with one GDNF-null allele show depletion of stem cell reserves, whereas mice overexpressing GDNF show accumulation of undifferentiated spermatogonia. They are unable to respond properly to differentiation signals and undergo apoptosis upon retinoic acid treatment. Nonmetastatic testicular tumors are regularly formed in older GDNF-overexpressing mice. Thus, GDNF contributes to paracrine regulation of spermatogonial self-renewal and differentiation.


Subject(s)
Drosophila Proteins , Nerve Growth Factors , Nerve Tissue Proteins/physiology , Spermatogenesis , Spermatogonia/cytology , Stem Cells/cytology , Animals , Apoptosis/drug effects , Cell Cycle , Cell Differentiation/drug effects , Cobalt/metabolism , Female , Gene Expression , Gene Targeting , Glial Cell Line-Derived Neurotrophic Factor , Glial Cell Line-Derived Neurotrophic Factor Receptors , Male , Mice , Mice, Transgenic , Mitosis , Nerve Tissue Proteins/genetics , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins c-ret , Receptor Protein-Tyrosine Kinases/genetics , Receptor Protein-Tyrosine Kinases/metabolism , Sertoli Cells/cytology , Sertoli Cells/physiology , Spermatogonia/drug effects , Testicular Neoplasms/pathology , Testis/anatomy & histology , Vitamin A/pharmacology
17.
FEBS Lett ; 463(1-2): 63-6, 1999 Dec 10.
Article in English | MEDLINE | ID: mdl-10601639

ABSTRACT

Glial cell line-derived neurotrophic factor (GDNF) has potentially great clinical importance in the treatment of Parkinson's disease and several other neurodegenerative diseases, however its intracellular signaling mechanisms are poorly understood. Here we show that upon GDNF binding glycosyl-phosphatidylinositol (GPI)-linked GDNF receptor alpha1 (GFRalpha1) activates cytoplasmic Src family tyrosine kinase(s) in Ret tyrosine kinase-deficient cultured mouse dorsal root ganglion neurons and in two Ret-negative cell lines. GFRalpha1-mediated Src-type kinase activation subsequently triggers phosphorylation of mitogen-activated protein kinase, cAMP response element binding protein and phospholipase Cgamma. We therefore conclude that GDNF can activate intracellular signaling pathways Ret-independently via GPI-linked GFRalpha1.


Subject(s)
Drosophila Proteins , Nerve Growth Factors , Nerve Tissue Proteins/pharmacology , Proto-Oncogene Proteins/metabolism , Receptor Protein-Tyrosine Kinases/metabolism , Signal Transduction/drug effects , src-Family Kinases/metabolism , 3T3 Cells , Animals , Cells, Cultured , Cyclic AMP Response Element-Binding Protein/metabolism , Enzyme Activation/drug effects , Ganglia, Spinal/metabolism , Glial Cell Line-Derived Neurotrophic Factor , Glial Cell Line-Derived Neurotrophic Factor Receptors , Humans , Isoenzymes/metabolism , MAP Kinase Signaling System/drug effects , Mice , Mitogen-Activated Protein Kinases/metabolism , Phospholipase C gamma , Phosphorylation/drug effects , Proto-Oncogene Proteins c-ret , Reverse Transcriptase Polymerase Chain Reaction , Time Factors , Transfection , Type C Phospholipases/metabolism
18.
Electrophoresis ; 20(18): 3670-6, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10612294

ABSTRACT

Protein patterns of nasal lavage fluid (NLF) and bronchoalveolar lavage fluid (BALF) were analyzed with two-dimensional gel electrophoresis (2-DE) and a number of previously unidentified proteins (lipocalin-1, cystatin S, transthyretin, immunoglobulin binding factor and an 11 kDa fragment of albumin) were identified by N-terminal amino acid sequencing. Lipocalin-1 was shown to be a dominant protein in NLF from healthy subjects but was almost undetectable in NLF from a patient with asthma. It further appeared that lipocalin-1 in NLF consists of eight forms with pIs between 5.2 and 5.5: three with the expected Mr of 17500, two with increased Mr (18000), and three truncated variants with Mr of 17000. Two forms of cystatin S were identified both in NLF and BALF: one with pI 5.1 and Mr 13000, and the other with pI4.9 and Mr 13500. The distribution of the two forms was clearly different in NLF and BALF from healthy subjects with the 4.9/13500 form constituting only about 13% in NLF but 69% in BALF. In NLF from subjects with upper airway irritation a twofold increased proportion of the 4.9/13500 form was detected. Amino acid sequence data and the spot position indicate that the 4.9/13500 form might be a phosphorylated variant of cystatin S. Lower levels of both forms of cystatin S were found in BALF from smokers than nonsmokers. The levels of transthyretin in NLF were decreased in subjects exposed to irritating chemicals. Finally, higher levels of IgBF were found in BALF from smokers than nonsmokers. Taken together, these results illustrate the potential biomedical and clinical applications of identifying proteins in 2-DE patterns of human BALF and NLF. The possibility to describe and monitor airway disorders at the molecular level is inferred.


Subject(s)
Bronchoalveolar Lavage Fluid/chemistry , Nose/chemistry , Proteins/analysis , Amino Acid Sequence , Electrophoresis, Gel, Two-Dimensional , Humans , Molecular Sequence Data , Proteins/chemistry
19.
Electrophoresis ; 20(4-5): 881-90, 1999.
Article in English | MEDLINE | ID: mdl-10344263

ABSTRACT

The anti-inflammatory proteins lipocortin-1 and Clara cell protein-16 (CC-16) were studied in two-dimensional gel electrophoresis (2-DE) protein patterns of human nasal lavage fluids (NLFs) and bronchoalveolar lavage fluids (BALFs). Seven forms of lipocortin-1 were detected with Western immunoblots: three isoforms with an apparently normal Mr of 38 kDa and pI of 5.9, 6.0 and 6.1, and four truncated variants with pI/kDa 6.0/36, 6.4/36, 7.0/33, and 7.4/34. Four 6 kDa isoforms of CC-16 were found with pI 4.6, 4.8, 4.9, and 5.2. Lipocortin-1 and CC-16 were expressed in all individuals tested although not all variants were found in each individual. The overall levels of lipocortin-1 were higher in BALF than NLF and there were significant differences in the distribution of the different lipocortin-1 forms between BALFs and NLFs. One patient with occupational asthma and four children with rhinitis had increased levels of one of the truncated lipocortin-1 forms in NLF (pI/kDa: 7.4/34) and decreased levels of the major CC-16 form (pI/kDa: 4.8/6). The levels of CC-16 but not of lipocortin-1 were higher in BALF from smokers than from nonsmokers. These results indicate that the levels of lipocortin-1 and CC-16 in NLF and BALF may be altered in inflammatory airway disorders. Furthermore, the identification of different forms of the two proteins makes possible more detailed studies on the role of these proteins in inflammatory disease processes and anti-inflammatory therapies.


Subject(s)
Annexin A1/analysis , Blotting, Western/methods , Bronchoalveolar Lavage Fluid/chemistry , Electrophoresis, Gel, Two-Dimensional/methods , Nasal Lavage Fluid/chemistry , Proteins/analysis , Uteroglobin , Asthma/immunology , Asthma/metabolism , Child , Humans , Protein Isoforms , Rhinitis/immunology , Rhinitis/metabolism
20.
Eur J Biochem ; 260(2): 453-60, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10095781

ABSTRACT

The early light-inducible proteins (ELIPs) in chloroplasts possess a high sequence homology with the chlorophyll a/b-binding proteins but differ from those proteins by their substoichiometric and transient appearance. In the present study ELIPs of pea were isolated by a two-step purification strategy: perfusion chromatography in combination with preparative isoelectric focussing. Two heterogeneous populations of ELIPs were obtained after chromatographic separation of solubilized thylakoid membranes using a weak anion exchange column. One of these populations contained ELIPs in a free form providing the first isolation of these proteins. To prove whether the isolated and pure forms of ELIP bind pigments, spectroscopic and chromatographic analysis were performed. Absorption spectra and TLC revealed the presence of chlorophyll a and lutein. Measurements of steady-state fluorescence emission spectra at 77 K exhibited a major peak at 674 nm typical for chlorophyll a bound to the protein matrix. The action spectrum of the fluorescence emission measured at 674 nm showed several peaks originating mainly from chlorophyll a. It is proposed that ELIPs are transient chlorophyll-binding proteins not involved in light-harvesting but functioning as scavengers for chlorophyll molecules during turnover of pigment-binding proteins.


Subject(s)
Pisum sativum/chemistry , Plant Proteins/isolation & purification , Arabidopsis Proteins , Chloroplasts/chemistry , Isoelectric Focusing , Plant Leaves/chemistry , Spectrometry, Fluorescence
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