Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID:Association of phosphorylated serine/arginine (SR) splicing factors with the U1-small ribonucleoprotein (snRNP) autoantigen complex accompanies apoptotic cell death. 946 5

Endothelial cells form a multifunctional cell lining that covers all of the inner surface of blood vessels and regulates several important physiological and pathological reactions. These include inflammation/immune reaction, blood vessel tonus, hemostasis/thrombosis, angiogenesis and so on. Thus, abnormalities of endothelial function may play crucial roles in the development of angitis syndrome, thrombosis/embolism, bleeding disseminated intravascular coagulation (DIC), and neovascularization in some pathological states including tumor growth and diabetic retinopathy. Research on endothelial cells now forms a new frontier termed 'Endotheliology'. Recent advances of the functional and structural aspects of endothelial cells are reviewed here mainly from the viewpoint of endothelial regulation of coagulation and the fibrinolytic system. First we show that the natural endothelial membrane protein thrombomodulin is localized not only on apical endothelial surface but also in caveolae. Since it has been reported that such factors involved in coagulation/fibrinolysis as tissue factor, tissue factor pathway inhibitor (TFPI), thrombin receptor and urokinase receptor are also localized in the caveolae, this membrane structure may act as a special component to regulate coagulation/fibrinolysis on the endothelial membrane surface. Next we demonstrate the signaling pathway of the thrombin receptor. Thrombin cleaves the N-terminus of the receptor as a substrate, exposing a new N-terminus. This newly exposed N-terminus acts as a ligand and activates platelets, endothelial cells and vascular smooth-muscle cells. We have identified that the signal from the thrombin receptor activates NF-kappaB through the activation of protein C kinase, tyrosine kinase and MAP kinase, and results in proliferation of the cells. We have also shown that the receptor is over-expressed on platelets from diabetes patients.
Lupus 1998
PMID:Biology of endothelium. 981 71

Much progress has been made in understanding how mammalian cells receive a diverse array of external stimuli and convert them into intracellular biochemical signals. Such efforts have identified a large number of signalling molecules. However, our knowledge is limited as to their pathophysiological role in particular diseases. We demonstrate herein that an integrin-linked signalling molecule, focal adhesion kinase p125FAK (FAK), is overexpressed in glomeruli of lupus-prone MRL/MP-lpr/lpr (MRL-lpr) mouse as compared to its congeneic MRL-+/+ strain. Increased expression was specifically demonstrated in glomeruli but not in other tissues examined. The overexpression was observed in 16-week-old MRL-lpr mice with active nephritis, as well as in younger animals at 4 weeks of age. Thus, the upregulation of FAK clearly preceded the clinical onset of nephritis. FAK in MRL-lpr glomeruli is highly tyrosine phosphorylated and is associated with adapter protein Grb2. Previous in vitro studies have shown that the association of FAK/Grb2 links cell adhesion to the Ras pathway, which ultimately stimulates mitogen-activated protein (MAP) kinase, an important regulator of cell proliferation. In accordance, we observed constitutive MAP kinase activation in MRL-lpr glomeruli. Our findings suggest that signalling pathways involving FAK are activated in MRL-lpr glomeruli, and are likely to play a role in the development and progression of autoimmune-mediated murine nephritis.
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PMID:Glomerular overexpression and increased tyrosine phosphorylation of focal adhesion kinase p125FAK in lupus-prone MRL/MP-lpr/lpr mice. 1045 17

To identify intrinsic defects in lupus, we studied short-term, CD4(+) T cell lines that were established from 16 lupus patients (active or inactive) and 15 normal subjects by stimulating once with anti-CD3, anti-CD28, and IL-2. After resting, the pure CD4(+) T cells were exposed to anergy-inducing stimulation with plate-bound anti-CD3 mAb in the absence of APC. Lupus T cells showed prolonged high level expression of CD40 ligand (CD40L, CD154) even in the face of anergy protocol, which shut down CD40L expression in normal T cells. The sustained CD40L expression in lupus T cells did not correlate with memory status or Th deviation, and was relatively independent of IL-2 or other autocrine or paracrine signals via CD28 or CTLA-4. Cyclosporin A could block CD40L expression by lupus T cells when added early during the anti-CD3 stimulation period, but only partially when added later, indicating that another mechanism regulates the prolonged hyperexpression of CD40L besides the Ca(2+) --> calcineurin-dependent NF-AT pathway. When exposed to the anergy protocol, lupus T cells, in marked contrast to normal T cells, did not phosphorylate Cbl/Cbl-b but continued to express strongly phosphorylated extracellular signal-regulated kinase (ERK); U0126, a specific inhibitor of mitogen-activated protein kinase kinase --> ERK, could block both the early and the prolonged hyperexpression of CD40L. Thus, pathways regulating the activities of Cbl and one particular mitogen-activated protein kinase, ERK, are involved in the prolonged hyperexpression of CD40L in lupus T cells.
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PMID:Regulatory defects in Cbl and mitogen-activated protein kinase (extracellular signal-related kinase) pathways cause persistent hyperexpression of CD40 ligand in human lupus T cells. 1108 8

Mesangial cells from MRL/lpr mice, a model of lupus, overproduce nitric oxide (NO) compared to controls. J series prostaglandins (PG) and thiazolidinediones block LPS stimulation of NO production via the activation of peroxisome proliferator-activator receptor-gamma (PPAR-gamma) in macrophages but utilize an alternative mechanism in microglial cells. We investigated the mechanism by which PGJ(2) inhibits NO production in LPS/IFN-gamma-stimulated MRL/lpr mesangial cells. Our results demonstrated that LPS/IFN-gamma addition to MRL/lpr mesangial cells stimulated iNOS activation, expression of p-38 kinase and p44/42 MAPK, and NF-kappaB translocation to the nucleus. Both pioglitazone, a specific PPAR-gamma agonist, and PGJ(2) blocked NO production, iNOS protein expression, and iNOS mRNA transcription. PGJ(2) failed to inhibit nuclear NF-kappaB translocation or p44/42 MAPK or p-38 kinase induction in stimulated mesangial cells. These data suggest that PGJ(2) blocks iNOS expression and subsequent NO production in mesangial cells via a PPAR-gamma-mediated mechanism either by interfering with NF-kappaB transcriptional activity or by an NF-kappaB-independent mechanism.
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PMID:Prostaglandin J(2) inhibition of mesangial cell iNOS expression. 1123 57

NZB mice demonstrate common and consistent abnormalities in B-cell activation and signalling. One of the hallmark characteristics of lupus disease is the prevalent hypergammaglobulinaemia, composed primarily of anti-nuclear antibodies. In addition to the hyperproliferation seen in mice exhibiting disease, the B cells also demonstrate a marked degree of hyperactivity in response to B-cell receptor occupancy. This points to an intrinsic defect in the signalling pathways regulating the response to an activation event. Correspondingly, B cells of NZB mice exhibit a significant lack of phosphatase activity, both at baseline and in response to stimulation. This is directly reflected by a higher level of phosphorylation of tyrosine residues. Individually, SAPK and SHIP-1, both players in the B-cell receptor signalling cascade, are also found to be abnormally phosphorylated in the NZB mouse.
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PMID:Phosphorylation abnormalities: NZB mice exhibit a B-cell signalling defect. 1241 80

The phosphorylation of p38 mitogen-activated protein kinase (MAPK) is responsible for the production and signal transduction of cytokines and chemokines. This study hypothesized that p38 MAPK activation is required for spontaneous autoimmune renal injury in MRL-Fas(lpr) mice, resembling human lupus erythematosus. FR167653, a specific inhibitor of p38 MAPK, is orally administrated from 3 or 4 mo of age in MRL-Fas(lpr) mice (at doses of 10 or 32mg/kg per day) until 6 mo of age. The phosphorylated p38 MAPK in kidneys of MRL-Fas(lpr) mice was evaluated. The number of phosphorylated p38 MAPK-positive cells was increased in diseased kidneys. The daily oral administration of FR167653 decreased p38 MAPK phosphorylation in kidneys, especially in a group of mice administered FR167653 (32 mg/kg per day) daily from 3 to 6 mo of age. FR167653 reduced the accumulation of macrophages and T cell and prevented kidney pathology, resulting in prolonged survival. In addition, FR167653 reduced expression of MCP-1 and TNF-alpha in the diseased kidneys and cultured tubular epithelial cells. Furthermore, FR167653 decreased IgG levels in the diseased kidneys and circulation. These results suggest that the phosphorylation of p38 MAPK is required for the pathogenesis of renal injury in MRL-Fas(lpr) mice followed by subsequent expression of renal cytokine/chemokine and IgG production. This study provides evidence that the regulation of p38 MAPK is a novel target for the therapy of renal injury in systemic lupus erythematosus.
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PMID:p38 Mitogen-activated protein kinase contributes to autoimmune renal injury in MRL-Fas lpr mice. 1250 38

The integrity of the Ras/Raf/mitogen-activated protein kinase (MAPK) cascade is critical for maintenance of T cell tolerance, a process that fails in patients with systemic lupus erythematosus (SLE). In this study we have examined the activity of mitogen-activated protein kinases ERK-1 and ERK-2 in resting and TCR-activated peripheral blood T lymphocytes from patients with SLE. We also examined the binding of Ras guanine nucleotide exchange factor, human Son of Sevenless (hSos), to cytosolic adapter protein growth factor receptor-bound protein 2. T cells from lupus patients showed diminished catalytic activity and TCR-driven dual phosphorylation of ERK-1 and ERK-2 upon stimulation through the TCR/CD3 receptor, a defect that may be related to altered translocation of hSos to the Ras/Raf membrane complex and diminished nuclear translocation of trans-acting factor AP-1. Defective MAPK activity triggered by TCR/ CD3 activation may alter the coordination of signals needed for normal interleukin-2 production and maintenance of tolerance in lupus T cells.
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PMID:Defective activity of ERK-1 and ERK-2 mitogen-activated protein kinases in peripheral blood T lymphocytes from patients with systemic lupus erythematosus: potential role of altered coupling of Ras guanine nucleotide exchange factor hSos to adapter protein Grb2 in lupus T cells. 1258 50

CpG sequences in self-DNA are an important potential trigger for autoantibody secretion in systemic lupus and other systemic autoimmune disorders. It is not known how this ubiquitous threat may be controlled by active mechanisms for maintaining self tolerance. Here we show that two distinct mechanisms oppose autoantibody secretion induced by CpG DNA in anergic B cells that are constantly binding self-antigen. Uncoupling of the antigen receptor (BCR) from a calcineurin-dependent pathway prevents signals that synergize with CpG DNA for proliferation. The BCR does not become desensitized by activating the extracellular response kinase (ERK) MAP kinase pathway, however, and continuous self-antigen signaling to ERK inhibits CpG DNA-induced plasma cell differentiation. These two mechanisms seem to act as a general control against autoantibody production elicited by Toll-like receptors, and their regulation of T cell-independent responses to Toll-like receptor 9 (TLR9) is probably crucial for resistance to systemic autoimmunity.
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PMID:Resistance to CpG DNA-induced autoimmunity through tolerogenic B cell antigen receptor ERK signaling. 1274 May 74

Bz-423 is a new benzodiazepine that has cytotoxic and cytostatic effects against a number of cell types in culture, and recent studies have shown efficacy in experimental lupus models in rodents. The present study demonstrates that treating human skin in organ culture with Bz-423 suppresses retinoid-induced epidermal hyperplasia. Bz-423 suppresses hyperplasia in organ culture at concentrations that also inhibit keratinocyte proliferation in monolayer culture but that are not cytotoxic for keratinocytes and do not inhibit fibroblast growth. Under conditions in which keratinocyte proliferation is inhibited, there is no measurable effect on epidermal growth factor receptor activation, but there is reduced signaling at the level of extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase. Suppression of keratinocyte growth by Bz-423 is associated with generation of intracellular oxidants. However, antioxidant treatment reduces keratinocyte cytotoxicity that occurs at high concentrations of Bz-423, but it does not inhibit growth suppression. Together, these data suggest that Bz-423 has the potential to limit the untoward effects associated with topical retinoid treatment, and in addition, may have therapeutic effects against other forms of epidermal hyperplasia.
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PMID:A novel benzodiazepine selectively inhibits keratinocyte proliferation and reduces retinoid-induced epidermal hyperplasia in organ-cultured human skin. 1557 71


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