Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 4 de 4
Filter
Add more filters










Database
Language
Publication year range
1.
Am J Transplant ; 8(12): 2558-68, 2008 Dec.
Article in English | MEDLINE | ID: mdl-19032224

ABSTRACT

Orthotopic liver transplantation (OLT) continues to be the only remedy for end-stage liver disease. In an attempt to decrease the ever-widening gap between organ donor and recipient numbers, and ultimately make more livers amenable to transplantation, we characterized the healthy human liver's response to ischemia and reperfusion-induced injury during transplantation. This was carried out by transcriptional profiling using cDNA microarray to identify genes whose expression was modulated at the 1-h postreperfusion time point. We observed that the map kinase phosphatase-1/dual-specificity phosphatase-1 (MKP-1/DUSP1) mRNA was strongly and significantly upregulated. Validation of this observation was carried out using reverse transcriptase-polymerase chain reaction (RT-PCR), immunoblotting and immunohistochemistry. In addition, we characterized the signaling pathways regulating MKP-1 expression using the human hepatoma cell line HepG2. Finally, by combining MKP-1 silencing with reperfusion-associated stresses, we reveal the preferential role of this protein in attenuating the activity of the JNK and p38(MAPK) pathways, and the resulting apoptosis, making MKP-1 a potential target for therapeutic intervention.


Subject(s)
Dual Specificity Phosphatase 1/metabolism , Liver Transplantation/physiology , Liver/metabolism , Reperfusion Injury/metabolism , Apoptosis/physiology , Biopsy , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/pathology , Cell Line, Tumor , Dual Specificity Phosphatase 1/genetics , Humans , Liver/pathology , Liver Neoplasms/metabolism , Liver Neoplasms/pathology , MAP Kinase Kinase 4/metabolism , Oligonucleotide Array Sequence Analysis , RNA, Messenger/metabolism , Reperfusion Injury/pathology , Reperfusion Injury/physiopathology , Signal Transduction/physiology , p38 Mitogen-Activated Protein Kinases/metabolism
2.
Cell Death Differ ; 14(3): 586-96, 2007 Mar.
Article in English | MEDLINE | ID: mdl-16858427

ABSTRACT

The endoplasmic reticulum (ER) has evolved specific mechanisms to ensure protein folding as well as the maintenance of its own homeostasis. When these functions are not achieved, specific ER stress signals are triggered to activate either adaptive or apoptotic responses. Here, we demonstrate that MCF-7 cells are resistant to tunicamycin-induced apoptosis. We show that the expression level of the ER chaperone calnexin can directly influence tunicamycin sensitivity in this cell line. Interestingly, the expression of a calnexin lacking the chaperone domain (DeltaE) partially restores their sensitivity to tunicamycin-induced apoptosis. Indeed, we show that DeltaE acts as a scaffold molecule to allow the cleavage of Bap31 and thus generate the proapoptotic p20 fragment. Utilizing the ability of MCF-7 cells to resist tunicamycin-induced apoptosis, we have characterized a molecular mechanism by which calnexin regulates ER-stress-mediated apoptosis in a manner independent of its chaperone functions but dependent of its binding to Bap31.


Subject(s)
Breast Neoplasms/metabolism , Calnexin/metabolism , Carcinoma/metabolism , Gene Expression Regulation, Neoplastic , Tunicamycin/pharmacology , Amino Acid Sequence , Apoptosis , Calnexin/genetics , Calnexin/physiology , Caspase 3/metabolism , Cell Line, Tumor , Clone Cells , Drug Resistance, Neoplasm , Endoplasmic Reticulum/drug effects , Endoplasmic Reticulum/metabolism , Enzyme Activation , Humans , Molecular Sequence Data
3.
Mol Biol Cell ; 16(4): 1629-39, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15659649

ABSTRACT

Rho GTPases are mainly known for their implication in cytoskeleton remodeling. They have also been recently shown to regulate various aspects of membrane trafficking. Here, we report the identification and the characterization of a novel Caenorhabditis elegans Cdc42-related protein, CRP-1, that shows atypical enzymatic characteristics in vitro. Expression in mouse fibroblasts revealed that, in contrast with CDC-42, CRP-1 was unable to reorganize the actin cytoskeleton and mainly localized to trans-Golgi network and recycling endosomes. This subcellular localization, as well as its expression profile restricted to a subset of epithelial-like cells in C. elegans, suggested a potential function for this protein in polarized membrane trafficking. Consistent with this hypothesis, alteration of CRP-1 expression affected the apical trafficking of CHE-14 in vulval and rectal epithelial cells and sphingolipids (C(6)-NBD-ceramide) uptake and/or trafficking in intestinal cells. However, it did not affect basolateral trafficking of myotactin in the pharynx and the targeting of IFB-2 and AJM-1, two cytosolic apical markers of intestine epithelial cells. Hence, our data demonstrate a function for CRP-1 in the regulation of membrane trafficking in a subset of cells with epithelial characteristics.


Subject(s)
Caenorhabditis elegans Proteins/chemistry , Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/metabolism , Cell Membrane/metabolism , Epithelial Cells/metabolism , cdc42 GTP-Binding Protein/chemistry , rho GTP-Binding Proteins/chemistry , rho GTP-Binding Proteins/metabolism , Actins/metabolism , Amino Acid Sequence , Animals , Biological Transport , Caenorhabditis elegans/chemistry , Caenorhabditis elegans/embryology , Caenorhabditis elegans/genetics , Caenorhabditis elegans Proteins/genetics , Cell Membrane/chemistry , Cytoskeleton/metabolism , Embryonic Development , Endosomes/chemistry , Endosomes/genetics , Endosomes/metabolism , Epithelial Cells/chemistry , Epithelial Cells/cytology , Mice , Molecular Sequence Data , Monomeric GTP-Binding Proteins/metabolism , Mutation/genetics , NIH 3T3 Cells , Phylogeny , Sequence Alignment , rho GTP-Binding Proteins/genetics , trans-Golgi Network/chemistry , trans-Golgi Network/metabolism
4.
Transplant Proc ; 36(6): 1766-8, 2004.
Article in English | MEDLINE | ID: mdl-15350473

ABSTRACT

BACKGROUND: The cellular events following liver ischemia/reperfusion (I/R) during transplantation are largely unknown. The spectrum of I/R damage to the liver can be clinically revealed by the development of primary graft dysfunction or nonfunction. Because viral-induced liver necrosis has been associated with the development of calcifications in an animal model, we investigated the spectrum of I/R changes identified at an ultrastructural level among livers after liver transplant (LT). MATERIALS AND METHODS: Random liver biopsies from five recipients with different degrees of liver dysfunction (LD) were processed for light (LM) and electron (EM) microscopic examination. The degree of calcification was estimated as mild-moderate or severe. The degree of cell vacuolization, used as a surrogate marker of cell necrosis, was reported as mild-moderate or severe. RESULTS: Two patients with severe LD had obvious calcifications by LM and EM examinations. Both showed significant vacuole formation, suggesting a severe degree of cell necrosis, and both succumbed to the sequelae of their LD. One patient showed evidence of mild calcifications at EM (but not LM) examination, with mild vacuole formation. The remaining two patients displayed no microcalcifications. Both presented only mild vacuole formation. Both patients recovered from LD and are currently alive. CONCLUSION: In this preliminary report, we conclude that the clinically observed degree of LD after orthotopic liver transplant (OLT)correlates well with ultrastructural modifications. These include calcification and vacuole formation. We believe that both findings can be used as surrogate markers of a clinically significant hepatic I/R injury.


Subject(s)
Liver Transplantation/pathology , Reperfusion Injury/pathology , Biopsy , Calcinosis/pathology , Graft Survival , Humans , Liver/ultrastructure , Necrosis , Postoperative Period
SELECTION OF CITATIONS
SEARCH DETAIL
...