ABSTRACT
Neural BC1 RNA is distributed in neuronal dendrites as RNA-protein complexes (BC1 RNPs) containing Translin. In this study, we demonstrated that the single-stranded DNA- and RNA-binding protein pur alpha and its isoform, pur beta, which have been implicated in control of DNA replication and transcription, linked BC1 RNA to microtubules (MTs). The binding site was within the 5' proximal region of BC1 RNA containing putative dendrite-targeting RNA motifs rich in G and U residues, suggesting that in the cytoplasm of neurons, these nuclear factors are involved in the BC1 RNA transport along dendritic MTs. The pur proteins were not components of BC1 RNP but appeared to associate with MTs in brain cells. Therefore, it is suggested that they may transiently interact with the RNP during transport. In this respect, the interaction of pur proteins with BC1 RNA could be regulated by the Translin present within the RNP, because the binding mode of these two classes of proteins (pur proteins and Translin) to the dendrite-targeting RNA motifs was mutually exclusive. As the motifs are well conserved in microtubule-associated protein 2a/b mRNA as well, the pur proteins may also play a role(s) in the dendritic transport of a subset of mRNAs.
Subject(s)
Cyclic AMP Response Element-Binding Protein/metabolism , DNA-Binding Proteins/metabolism , Dendrites/metabolism , Microtubules/metabolism , RNA/metabolism , Ribonucleoproteins, Small Cytoplasmic/metabolism , Animals , Binding Sites/genetics , Biological Transport/genetics , Brain Chemistry , Cyclic AMP Response Element-Binding Protein/chemistry , DNA-Binding Proteins/chemistry , Electrophoresis, Polyacrylamide Gel , Liver/chemistry , Macromolecular Substances , Mice , Microtubule-Associated Proteins/chemistry , Microtubule-Associated Proteins/metabolism , Nerve Tissue Proteins , Nucleic Acid Conformation , RNA/analysis , RNA, Long Noncoding , RNA, Untranslated , RNA-Binding Proteins/chemistry , RNA-Binding Proteins/metabolism , Ribonucleoproteins, Small Cytoplasmic/genetics , Sequence Analysis, Protein , Substrate Specificity , Transcription FactorsABSTRACT
More than fifty chalcone derivatives were synthesized to examine structure-activity relationships against human aldose reductase. Certain 2',4'-dihydroxychalcone derivatives inhibited human aldose reductase activities, and 2',4',2, 4-tetrahydroxychalcone and 2',4',2-trihydroxychalcone showed potent inhibitory activity with IC50 values of 7.4x10(-9) M and 1.6x10(-7) M, respectively. On the other hand, cis-form chalcones, which were isomerized from the original trans-forms by irradiation of daylight in methanol solution, promoted the activity of human aldose reductase.
Subject(s)
Aldehyde Reductase/antagonists & inhibitors , Chalcone/pharmacology , Chalcone/analogs & derivatives , Humans , Recombinant Proteins/antagonists & inhibitors , Stereoisomerism , Structure-Activity RelationshipSubject(s)
Gastrointestinal Diseases/etiology , Isoenzymes , Prostaglandin-Endoperoxide Synthases , Animals , Apoptosis , Basement Membrane/metabolism , Cell Differentiation , Cyclooxygenase 1 , Cyclooxygenase 2 , Extracellular Matrix/metabolism , Humans , Isoenzymes/metabolism , Isoenzymes/physiology , Membrane Proteins , Prostaglandin-Endoperoxide Synthases/metabolism , Prostaglandin-Endoperoxide Synthases/physiology , Prostaglandins/biosynthesis , Prostaglandins/physiologySubject(s)
Carcinoma, Hepatocellular/diagnosis , Liver Neoplasms/diagnosis , Magnetic Resonance Imaging , Tomography, X-Ray Computed , Aged , Angiography, Digital Subtraction , Carcinoma, Hepatocellular/diagnostic imaging , Carcinoma, Hepatocellular/pathology , Female , Humans , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/pathologyABSTRACT
Kupffer cells (KC) become activated in response to lipopolysaccharide (LPS) and produce a variety of mediators. Among them, TNF alpha is known to injure the liver. Here we report that TNF alpha mediates apoptosis in KC and sinusoidal endothelial cells. After stimulation for 24 h with LPS (0-10 micrograms/mL), apoptosis in KC detected by TUNEL TdT-mediated dUTP-biotin nick end labelling (TUNEL) increased in a concentration-dependent manner (0 micrograms/mL, 12 +/- 4%; 0.1 microgram/mL, 36 +/- 11%; 1.0 micrograms/mL, 65 +/- 9%; 10 micrograms/mL, 78 +/- 15%). In contrast, co-incubation of endothelial cells with LPS-stimulated KC resulted in a marked increase in TUNEL-positive endothelial cells. TNF alpha antibody blocked apoptosis in both KC and endothelial cells. Apoptosis was observed in cells adjacent to or in contact with KC. Reducing transmembrane TNF alpha expressed on KC also led to a decrease in endothelial cell apoptosis, suggesting that transmembrane TNF alpha is implicated in the cell-to-cell contact mechanism of induction of apoptosis. Thus, TNF alpha mediates apoptosis in KC and endothelial cells.
