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.
Bosn J Basic Med Sci ; 16(2): 126-31, 2016 Jan 14.
Article in English | MEDLINE | ID: mdl-26773180

ABSTRACT

Nod-like receptor protein 3 (NLRP3) inflammasome has been implicated in alcoholic liver disease. Chronic alcohol consumption enhances gut permeability and causes microbial translocation. The present study explored the activation of the NLRP3 inflammasome by Escherichia coli RNA in hepatic stellate cells (HSCs), and the potential role of NLRP3 inflammasome in hepatic fibrosis. E. coli RNA transfection induced HSC-T6 cells to secrete and express mature interleukin-1 beta (IL-1ß), which was abolished by NLRP3 siRNA pretreatment. In addition, E. coli RNA transfection enhanced caspase-1 expression, whereas reduced caspase-1 precursor (pro-caspase-1) expression. E. coli RNA-stimulated transforming growth factor beta 1 (TGF-ß1) overproduction in HSC-T6 cells, which was blocked by recombinant IL-1 receptor antagonist (rIL-1Ra) or nuclear factor κB inhibitor BAY 11-7082. Furthermore, E. coli RNA-induced overexpression of pro-fibrogenic factors was suppressed by rIL-1Ra or TGF-ß receptor inhibitor A83-01. These results demonstrate that E. coli RNA can stimulate NLRP3 inflammasome activation, which leads to excessive production of pro-fibrogenic factors, suggesting that NLRP3 inflammasome activation in HSCs may play a role in hepatic fibrosis.


Subject(s)
Escherichia coli/chemistry , Hepatic Stellate Cells/metabolism , Inflammasomes/genetics , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , RNA, Bacterial/toxicity , Transforming Growth Factor beta/biosynthesis , Caspase 1/biosynthesis , Caspase 1/genetics , Humans , Inflammasomes/drug effects , Liver Cirrhosis/pathology , NF-kappa B/antagonists & inhibitors , NLR Family, Pyrin Domain-Containing 3 Protein/drug effects , Nitriles/pharmacology , Protein Serine-Threonine Kinases/biosynthesis , Protein Serine-Threonine Kinases/genetics , Pyrazoles/pharmacology , RNA, Small Interfering , Receptor, Transforming Growth Factor-beta Type II , Receptors, Transforming Growth Factor beta/antagonists & inhibitors , Receptors, Transforming Growth Factor beta/biosynthesis , Receptors, Transforming Growth Factor beta/genetics , Sulfones/pharmacology , Thiosemicarbazones/pharmacology
2.
Ophthalmology ; 119(7): e24-9, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22578449

ABSTRACT

OBJECTIVE: To evaluate the intraocular reactivity to organic contaminants of ophthalmic devices in the rabbit. DESIGN: Experimental animal study. PARTICIPANTS: Fifty New Zealand white rabbits. METHODS: The rabbits were allocated to 10 groups of 5 each to receive 2 different doses of human albumin and nonhuman nucleic acids and their respective vehicle controls, a denatured cohesive ophthalmic viscosurgical device (OVD) and a denatured dispersive OVD and their respective nondenatured controls. All 10 eyes in each treatment group received bilateral intracameral injection of the test materials. All the eyes in the study were examined by slit-lamp biomicroscopy at baseline and 6, 9, 24, 48, and 72 hours. Pachymetry was also performed on eyes exposed to albumin, protein vehicle control, and the OVDs at these time points. MAIN OUTCOME MEASURES: Corneal thickness, grade of corneal clouding, anterior chamber (AC), cells, flare and fibrin, iridal hyperemia, cell and fibrin on lens surface, and onset time. RESULTS: There were no inflammatory signs in any eyes exposed to human albumin. Anterior chamber cells (1+ to 3+) and flare and fibrin (1+ to 2+), along with cells and fibrin on the lens surface, were seen in the eyes exposed to the nucleic acid samples, and they resolved in 24 hours. Mild (mostly 1+) conjunctival congestion, cells, flare, and fibrin were seen in a few eyes exposed to the 2 denatured OVDs and their controls, with the response durations being shorter in the denatured OVD eyes (24 hours) than in the nondenatured OVD eyes (48 hours). Anterior chamber inflammation was generally observed in fewer denatured OVD eyes than in nondenatured OVD eyes, particularly the dispersive OVD eyes. CONCLUSIONS: Intracameral injection of human albumin protein did not cause ocular inflammation. Nucleic acid intracamerally injected into rabbit eyes caused acute inflammation that quickly resolved. Cohesive and dispersive OVD denatured by drying and steam sterilization alone did not cause ocular inflammation.


Subject(s)
Albumins/toxicity , Anterior Eye Segment/drug effects , DNA/toxicity , Equipment Contamination , RNA, Bacterial/toxicity , Uveitis, Anterior/chemically induced , Animals , Models, Animal , Organic Chemicals/toxicity , Rabbits
3.
Biochemistry ; 45(26): 8079-87, 2006 Jul 04.
Article in English | MEDLINE | ID: mdl-16800632

ABSTRACT

Divergent tRNA substrate recognition patterns distinguish the two distinct forms of aspartyl-tRNA synthetase (AspRS) that exist in different bacteria. In some cases, a canonical, discriminating AspRS (D-AspRS) specifically generates Asp-tRNA(Asp) and usually coexists with asparaginyl-tRNA synthetase (AsnRS). In other bacteria, particularly those that lack AsnRS, AspRS is nondiscriminating (ND-AspRS) and generates both Asp-tRNA(Asp) and the noncanonical, misacylated Asp-tRNA(Asn); this misacylated tRNA is subsequently repaired by the glutamine-dependent Asp-tRNA(Asn)/Glu-tRNA(Gln) amidotransferase (Asp/Glu-Adt). The molecular features that distinguish the closely related bacterial D-AspRS and ND-AspRS are not well-understood. Here, we report the first characterization of the ND-AspRS from the human pathogen Helicobacter pylori (H. pylori or Hp). This enzyme is toxic when heterologously overexpressed in Escherichia coli. This toxicity is rescued upon coexpression of the Hp Asp/Glu-Adt, indicating that Hp Asp/Glu-Adt can utilize E. coli Asp-tRNA(Asn) as a substrate. Finally, mutations in the anticodon-binding domain of Hp ND-AspRS reduce this enzyme's ability to misacylate tRNA(Asn), in a manner that correlates with the toxicity of the enzyme in E. coli.


Subject(s)
Anticodon/genetics , Aspartate-tRNA Ligase/genetics , Helicobacter pylori/enzymology , RNA, Transfer/toxicity , Amino Acid Sequence , Aspartate-tRNA Ligase/chemistry , Aspartate-tRNA Ligase/metabolism , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Cloning, Molecular , Conserved Sequence , Escherichia coli/enzymology , Escherichia coli/genetics , Helicobacter pylori/genetics , Kinetics , Models, Molecular , Molecular Sequence Data , Protein Conformation , RNA, Bacterial/toxicity , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Sequence Alignment , Sequence Homology, Amino Acid
SELECTION OF CITATIONS
SEARCH DETAIL
...