PubMed Health⌕ Search

Biomedical subjects

P J Utz

Publications and source records attributed to P J Utz.

At least 19 recordsLinked to original sources
PubMed2005

Suppression of autoimmunity via microbial mimics of altered peptide ligands.

Molecular mimics of self-antigens can behave as altered peptide ligands and serve to ameliorate autoimmune disease. Analysis of experimental autoimmune encephalomyelitis with proteomic autoantibody microarrays reveals that there might exist a wide variety of microbes with features that mimic self-epitopes. Autoimmunity could therefore be modulated via microbial immunity, which may account for relapse and remission of ongoing disease.

Animals↗
PubMed2005

Detection of apoptosis-specific autoantibodies directed against granzyme B-induced cleavage fragments of the SS-B (La) autoantigen in sera from patients with primary Sjögren's syndrome.

The objective of this study was to detect autoantibodies against granzyme B cleavage products in sera from patients with primary Sjögren's syndrome (SS). Cell lysates derived from human salivary gland (HSG) cell lines were incubated with granzyme B. The susceptibility to the generation of cleavage fragments of SS autoantigens was assayed by immunoblotting using sera from 57 primary SS patients, 17 primary SS patients with malignant lymphoma (ML), 28 systemic lupus erythematosus (SLE) patients, and 20 healthy controls. A 27 kD protein was recognized by serum autoantibodies in 8 (14.0%) of 57 primary SS patients, 5 (29.4%) of 17 SS patients with ML, 2 (7.1%) of 28 SLE patients, but not in 20 normal subjects. This protein was recognized by anti-SSB (La) monoclonal antibodies. Granzyme B-treated recombinant La protein was also shown to migrate as a discrete 27 kD protein by SDS PAGE. Blocking studies demonstrated the existence of an apoptosis-specific B cell epitope present in sera from 2 of 8 primary SS patients and in 2 of 5 primary SS patients with ML which recognized the 27 kD protein. Granzyme B-induced La fragments are generated during cytotoxicity in vitro. This is the first report describing autoantibodies in sera from primary SS patients that specifically recognize fragments of the La protein that are produced by the granzyme B protease.

Adult↗
PubMed2004

Multiplexed assays for identification of biomarkers and surrogate markers in systemic lupus erythematosus.

Validated biomarkers and surrogate markers are badly needed for monitoring patients with systemic lupus erythematosus (SLE), both for routine clinical care and for clinical trials research. SLE is difficult to study in clinical trials, in part because the disease is so heterogeneous. Very few useful markers have been identified, and even those that historically have been thought to be valid have been recently questioned. This report will focus on the use of emerging multiplexed assay formats that enable analysis of hundreds or even thousands of analytes simultaneously. Their potential and pitfalls for monitoring patients with SLE, particularly those enrolled in clinical trials testing novel therapeutics, will be discussed.

Autoantibodies↗
PubMed2001

21st European Workshop for Rheumatology Research, Vienna, Austria, 1-4 March 2001.

Major advances in technology now drive how we approach questions in immunology, particularly in analyzing complex data sets commonly encountered in genomics and proteomics studies. Active areas of investigation include development of novel technologies, identification of elusive target antigens for RA and other diseases, dissection of signaling pathways connecting the lymphocyte cell surface with the nucleus, and exploration of new avenues for therapeutic interventions. The European Workshop for Rheumatology Research (EWRR) is a forum for many European and non-European scientists to present research findings of high quality. Arthritis researchers from around the globe should be strongly encouraged to attend future meetings, the next of which is the 22nd EWRR meeting in Leiden, the Netherlands, in 2002.

Animals↗
PubMed2001

Monoclonal antibodies derived from BALB/c mice immunized with apoptotic Jurkat T cells recognize known autoantigens.

It has been postulated that post-translational modifications and relocalization of proteins during apoptosis may lead to presentation of these molecules to the immune system in such a way that normal mechanisms of tolerance are bypassed. In the present study, Jurkat cells were induced to undergo apoptosis by treatment with the chemotherapeutic agent Ara-C. BALB/c mice were then immunized with the apoptotic cells and hybridomas were generated. Using an indirect immunofluorescence assay, the monoclonal antibodies produced were screened by flow cytometry for those monoclonal antibodies demonstrating reactivity with permeabilized apoptotic Jurkat cells but not with non-permeabilized normal or apoptotic Jurkat cells. Of 281 monoclonal antibodies, 20 monoclonal antibodies with these properties were selected for further analysis. Using 32P- or 35S-metabolically labelled Jurkat cells, these selected monoclonal antibodies were screened for their ability to recognize autoantigens by immunoprecipitation and Western blotting. Well characterized autoimmune sera were then used to confirm the identity of autoantigens by immunoblotting. We demonstrate that immunization of normal mice with apoptotic Jurkat cells results in the formation of antibodies targeting multiple autoantigens or autoantigen complexes, including Ku, rRNPs, snRNPs and vimentin. These findings are consistent with the hypothesis that apoptosis can contribute to the development of autoimmunity.

Animals↗
PubMed2000

Death, autoantigen modifications, and tolerance.

Autoantibodies present in the serum of patients with a variety of inflammatory diseases have proven useful as diagnostic markers and as probes with which to elucidate biochemical and signaling pathways. The mechanisms governing the generation of autoantibodies remain elusive, constituting a critical missing link in our understanding of rheumatologic illnesses. Several lines of experimentation in recent years have strongly implicated events surrounding cell death in this process. This review will address the potential role played by death-specific modifications of autoantigens in bypassing tolerance to highly conserved autoantigens, including nucleic acids, lipids, and proteins.

Animals↗
PubMed2000

Small nucleolar RNP scleroderma autoantigens associate with phosphorylated serine/arginine splicing factors during apoptosis.

OBJECTIVE: Proteins that are phosphorylated during apoptosis are commonly precipitated by autoantibodies found in the sera of patients with systemic lupus erythematosus. We sought to determine whether scleroderma autoantigens such as small nucleolar RNPs (snoRNP) also associate with phosphoproteins in response to various cellular stressors. METHODS: We screened a panel of monoclonal antibodies derived from mice exposed to mercury, a well-characterized murine model of the anti-snoRNP autoimmune response, for the ability to selectively precipitate phosphoproteins from radiolabeled lysates prepared from Jurkat T cells subjected to stressful stimuli. RESULTS: Monoclonal antibodies reactive with snoRNPs precipitated a phosphoprotein complex (pp42, pp34, and pp23) from lysates prepared from apoptotic cells. Several novel phosphoproteins (pp62 and pp18) were also observed. The phosphorylation and/or recruitment of these proteins to the snoRNP complex is induced by multiple apoptotic stimuli (e.g., Fas ligation, anisomycin, or ultraviolet irradiation), an effect that is blocked by overexpression of Bcl-2. We were unable to demonstrate an association of the phosphoprotein complex with snoRNPs in cells treated with the xenobiotic agent mercury. The snoRNP-associated phosphoprotein complex is composed of serine/arginine (SR) splicing factors, including SRp40. CONCLUSION: The association of phosphorylated SR proteins with snoRNPs in cells undergoing apoptosis suggests that the immune response to fibrillarin that characterizes a subset of patients with scleroderma may be related to cell death induced by apoptotic stimuli (e.g., Fas ligation, irradiation, or chemical toxins), or by exposure to mercury.

Animals↗
PubMed2000

The fate of U1 snRNP during anti-Fas induced apoptosis: specific cleavage of the U1 snRNA molecule.

During apoptosis, the U1-70K protein, a component of the spliceosomal U1 snRNP complex, is specifically cleaved by the enzyme caspase-3, converting it into a C-terminally truncated 40-kDa fragment. In this study, we show that the 40-kDa U1-70K fragment is still associated with the complete U1 snRNP complex, and that no obvious modifications occur with the U1 snRNP associated proteins U1A, U1C and Sm-B/B'. Furthermore, it is described for the first time that the U1 snRNA molecule, which is the backbone of the U1 snRNP complex, is modified during apoptosis by the specific removal of the first 5 - 6 nucleotides including the 2,2, 7-trimethylguanosine (TMG) cap. The observations that U1 snRNA cleavage is very specific (no such modifications were detected for the other U snRNAs tested) and that U1 snRNA cleavage is markedly inhibited in the presence of caspase inhibitors, indicate that an apoptotically activated ribonuclease is responsible for the specific modification of U1 snRNA during apoptosis.

Amino Acid Chloromethyl Ketones↗
PubMed2000

Life and death decisions: regulation of apoptosis by proteolysis of signaling molecules.

Caspases are the major executioners of cell death, serving as molecular guillotines to behead many proteins required for maintenance of cellular homeostasis. Identification of caspase substrates has taken on increasing importance as we attempt to better understand the molecular mechanisms involved in regulating the struggle between life and death. Many caspase substrates have been described and include RNA binding proteins such as La and U1-70 kD, structural proteins such as keratin and nuclear lamins, and transcription factors or their regulatory proteins that include IkappaB, SP1, and SREBP. Kinases and other signaling proteins are perfectly suited to regulate life and death decisions in response to cellular stressors and have only recently been identified as important caspase substrates. Here we review the current status of signaling pathways that are activated, inactivated or dysregulated by proteases such as caspases and calpain to control entry into apoptosis. The emerging concept that some caspase pathways may be inhibited by cellular and viral apoptosis inhibitory proteins while other caspase pathways are preserved suggests that a subset of these kinases may exist as cleaved 'isoforms' in cells that are not destined to perish. By acting as executioners and as important 'molecular sensors' of the degree of cellular injury, the signaling proteins described in this review are strong candidates to mediate downstream events, both in condemned and in viable cells.

Animals↗
PubMed1999

Rapid nucleolytic degradation of the small cytoplasmic Y RNAs during apoptosis.

We have investigated the fate of the RNA components of small ribonucleoprotein particles in apoptotic cells. We show that the cytoplasmic Ro ribonucleoprotein-associated Y RNAs are specifically and rapidly degraded during apoptosis via a caspase-dependent mechanism. This is the first study describing the selective degradation of a specific class of small structural RNA molecules in apoptotic cells. Cleavage and subsequent truncation of Y RNAs was observed upon exposure of cells to a variety of apoptotic stimuli and were found to be inhibited by Bcl-2, zinc, and several caspase inhibitors. These results indicate that apoptotic degradation of Y RNAs is dependent on caspase activation, which suggests that the nucleolytic activity responsible for hY RNA degradation is activated downstream of the caspase cascade. The Y RNA degradation products remain bound by the Ro60 protein and in part also by the La protein, the only two proteins known to be stably associated with intact Ro ribonucleoprotein particles. The size of the Y RNA degradation products is consistent with the protection from degradation of the most highly conserved region of the Y RNAs by the bound Ro60 and La proteins. Our results indicate that the rapid abrogation of the yet unknown function of Y RNAs might be an early step in the systemic deactivation of the dying cell.

Anisomycin↗
PubMed1999

The La (SS-B) autoantigen, a key protein in RNA biogenesis, is dephosphorylated and cleaved early during apoptosis.

In the past few years, a role for apoptotic processes in the development of autoimmune diseases has been suggested. An increasing number of cellular proteins, which are modified during apoptosis, has been described, and many of these proteins have been identified as autoantigens. We have studied the effects of apoptosis on the La protein in more detail and for the first time demonstrate that this autoantigen is rapidly dephosphorylated after the induction of apoptosis. Dephosphorylation of the La protein was observed after induction of apoptosis by several initiators and in various cell types. Furthermore, we demonstrate that at least a subset of the La protein is proteolytically cleaved in vivo, generating a 45 kDa fragment. Dephosphorylation as well as cleavage of La is inhibited by ZnSO4 as well as by several tetrapeptide caspase inhibitors, indicating that these processes require the activation of caspases. Dephosphorylation of La is inhibited by low concentrations of okadaic acid, suggesting that a PP2A-like phosphatase is involved. Generation of the 45 kDa fragment is consistent with proteolytic cleavage at amino acids 371 and/or 374. The possible significance of the apoptotic changes in the La protein for autoantibody production is discussed.

Amino Acid Sequence↗
PubMed1998

The 72-kDa component of signal recognition particle is cleaved during apoptosis.

Proteins cleaved by apoptotic caspases are commonly recognized by autoantibodies found in the serum of patients with rheumatic disease. We report that the 72-kDa signal recognition particle (SRP) protein, a rare target of autoantibodies found in the serum of patients with dermatomyositis and systemic lupus erythematosus, is rapidly cleaved in Jurkat T cells treated with apoptotic (i.e. Fas ligation, treatment with gamma or ultraviolet radiation, or co-culture with anisomycin or staurosporine) but not proliferative (CD3 cross-linking) stimuli. Cleavage of SRP 72 produces a 66-kDa amino-terminal fragment and a 6-kDa carboxyl-terminal fragment that is selectively phosphorylated on serine residues. Cleavage of SRP 72 is prevented by chemical and peptide caspase inhibitors, and by overexpression of bcl-2, an inhibitor of apoptotic cell death. Analysis of the carboxyl terminus of SRP 72 has identified a putative cleavage site (SELD/A) for group III caspases, and carboxyl-terminal serine residues that are highly conserved in phylogeny. Both serine phosphorylation and caspase cleavage of SRP 72 are observed in cells derived from human, dog, rat, and mouse. Canine SRP 72 is cleaved in vitro by recombinant caspase 3 but retains the ability to mediate transport of a signal peptide-containing protein into the endoplasmic reticulum lumen. The 72-kDa component of the SRP joins a growing list of autoantigens that undergo post-translational modifications during programmed cell death.

Amino Acid Sequence↗
PubMed1998

Association of phosphorylated serine/arginine (SR) splicing factors with the U1-small ribonucleoprotein (snRNP) autoantigen complex accompanies apoptotic cell death.

Proteins subject to proteolysis or phosphorylation during apoptosis are commonly precipitated by autoantibodies found in the serum of patients with systemic lupus erythematosus (SLE). We screened a panel of murine monoclonal and human monospecific sera reactive with known autoantigens for their ability to selectively precipitate phosphoproteins from apoptotic Jurkat T cell lysates. Sera known to recognize the U1-small nuclear ribonucleoprotein (snRNP) complex (confirmed by their ability to precipitate U1-snRNA) selectively precipitated a phosphoprotein complex (pp54, pp42, pp34, and pp23) from apoptotic lysates. Monoclonal antibodies reactive with U1-snRNP proteins precipitated the same phosphoprotein complex from apoptotic lysates. The phosphorylation and/or recruitment of these proteins to the U1-snRNP complex is induced by multiple apoptotic stimuli (e.g., Fas ligation, gamma irradiation, or UV irradiation), and is blocked by overexpression of bcl-2. The U1-snRNP-associated phosphoprotein complex is immunoprecipitated by monoclonal antibodies reactive with serine/arginine (SR) proteins that comprise a structurally related family of splicing factors. The association of phosphorylated SR proteins with the U1-snRNP complex in cells undergoing apoptosis suggests a mechanism for regulation of alternative splicing of apoptotic effector molecules.

Animals↗
PubMed1997

Proteins phosphorylated during stress-induced apoptosis are common targets for autoantibody production in patients with systemic lupus erythematosus.

Proteins cleaved by interleukin-1 beta converting enzyme family proteases during apoptosis are common targets for autoantibody production in patients with systemic lupus erythematosus (SLE). We have tested the possibility that proteins phosphorylated in cells undergoing apoptosis are also targets for autoantibody production in patients with autoimmune disease. Sera from 9/12 patients containing antinuclear antibodies (10/12 meeting diagnostic criteria for SLE or a lupus overlap syndrome), precipitated new phosphoproteins from lysates derived from Jurkat T cells treated with apoptotic stimuli (i.e., Fas-ligation, gamma irradiation, ultraviolet irradiation), but not with an activation (i.e., CD3-ligation) stimulus. Sera derived from individual patients precipitated different combinations of seven distinct serine-phosphorylated proteins. None of these phosphoproteins were included in precipitates prepared using sera from patients with diseases that are not associated with autoantibody production or using serum from rheumatoid arthritis patients. Protein phosphorylation precedes, or is coincident with, the induction of DNA fragmentation, and is not observed when apoptosis is inhibited by overexpression of bcl-2. Serum from four patients precipitated a serine/threonine kinase from apoptotic cell lysates that phosphorylates proteins of 23-, 34-, and 46-kD in in vitro kinase assays. Our results suggest that proteins phosphorylated during apoptosis may be preferred targets for autoantibody production in patients with SLE.

Apoptosis↗
PubMed1989

SUP-HD1: a new Hodgkin's disease-derived cell line with lymphoid features produces interferon-gamma.

A new cell line, SUP-HD1, was established from the pleural effusion of a patient with nodular sclerosing Hodgkin's disease (NSHD). The SUP-HD1 cells had the characteristic morphology of Reed-Sternberg cells and contained acid phosphatase and nonspecific esterase. The cells lacked the Epstein-Barr virus (EBV) genome and reacted with monoclonal antibodies (MoAbs) against CD15 (Leu-M1), CD25 (Tac), CD71 (OKT9), Ki67, and HLA-Dr. However, the SUP-HD1 cells were nonreactive with MoAbs that specifically identify T lymphocytes, B lymphocytes, and macrophage/myeloid cells. Karyotype analysis of the cell line showed clonal abnormalities involving 1p13, 7p15, 8q22, and 11q23, chromosomal locations, at which breakpoints have been reported in HD. Southern blot analysis demonstrated rearrangement of the immunoglobulin heavy chain and kappa light chain genes as well as the gene for the beta chain of the T-cell receptor (TCR). Transcriptional analysis showed expression of RNAs for kappa light chain, interferon-gamma (IFN-gamma), and interleukin-2 receptor (IL-2R) but not IL-2. The SUP-HD1 cells lacked cytoplasmic and surface immunoglobulin heavy chain, but a small amount of cytoplasmic kappa light chain was detected. The presence of nuclear factor kappa B (NF kappa B), a B-lymphocyte-associated transcription factor, was demonstrated in stimulated and unstimulated cells. In addition, the SUP-HD1 cell line, produced IFN-gamma, a T-lymphocyte-associated lymphokine. Based on these data, the SUP-HD1 cells appear to be aberrant lymphocytes with characteristics of both activated B and T lymphocytes. Elaboration of lymphokines such as IFN-gamma by the malignant cells may represent one explanation for the unique clinical and pathologic features of HD.

Adult↗
PubMed1988

Effects of the thiazolidinedione derivative CGP 19984 on growth and endocrine function of the MtT-W10 transplantable mammosomatotropic pituitary tumor in female rats.

The thiazolidinedione derivative CGP 19984 has previously been shown to suppress the growth of hormone-dependent mammary and prostatic tumors, primarily by reducing gonadotropin and subsequently gonadal steroid secretion. The present study examines the effects of CGP 19984 on the growth and hormone secretion of the autonomous, but estrogen-responsive, MtT-W10 mammosomatotropic transplantable rat pituitary tumor. Intact tumor-bearing Wistar/Furth female rats were administered vehicle or 25, 100, or 250 mg/kg CGP 19984 p.o., 5 x week for 4 weeks. CGP 19984 was found to significantly reduce MtT-W10 tumor growth and weight and reduce prolactin and growth hormone (GH) secretion in a dose-responsive manner. A similar study in ovariectomized rats also showed that CGP 19984 treatment suppressed MtT-W10 pituitary tumor growth, weight and hormone secretion in a dose-responsive manner, suggesting a direct inhibitory action of this drug on the tumor. In a third study, bromocryptine (CB-154; 5 mg/kg) and CGP 19984 (50 mg/kg) were both found to be effective in suppressing growth of the MtT-W10 tumor in intact female rats. However, rats treated with CGP 19984 alone had reduced serum and tumor GH and prolactin concentrations, while rats treated with CB-154 alone had reduced serum and tumor prolactin, but no change in GH concentrations. These results suggest that CGP 19984 effectively inhibits growth and hormone secretion of the autonomous MtT-W10 pituitary tumor by apparently suppressing both somatotropic and lactotropic cell populations within the tumor. Furthermore, these findings indicate that CGP 19984 may be an effective alternative to CB-154 in the clinical treatment of prolactin-producing adenomas, as well as other types of pituitary adenomas.

Animals↗