Transcriptional regulation of ADAMTS13.
The metalloproteinase ADAMTS13 cleaves VWF multimers instantaneously when they are released from endothelial cells. Absent or manifestly diminished proteolytic activity of ADAMTS13 results in the appearance and accumulation of ultralarge VWF multimers (ULVWFM) in plasma, characterised by the manifestation of Thrombotic Thrombocytopenic Purpura (TTP). Despite congenital defects, infections and the actions of drugs such as cyclosporine A, doxycycline and corticosteroids apparently are involved in its development. To examine the possibility of transcriptional regulation of ADAMTS13 activity, we analyzed RNA levels in various cell culture systems and the response to known and assumed modulators of gene expression. We demonstrate the expression of ADAMTS13 in liver homogenates and a parenchyma liver cell culture system Hep3B, supporting the hypothesis that liver is an important source of plasma ADAMTS13, whereas there was no alteration in gene expression after stimulation of liver cells with proinflammatory stimuli such as endotoxin, TNF-alpha, IL-6, IL-1beta as well as immuno-suppressive agents, such as cyclosporine A, a variety of steroids as well as doxycycline. Therefore, we analysed the ADAMTS13 gene for binding sites of transcription factors in silico and compared the data with those found in two sets of 24 genes considered either as differentially regulated by prototypic inflammatory regulation or as unvaried under various conditions. On the basis of these data, the promotor of ADAMTS13 features the characteristics of a gene, which remains unvaried under a variety of conditions. To our knowledge, the current data demonstrate for the first time, that an alteration in transcriptional activity is negligible in accounting for diminished proteolytic activity as observed under various experimental and, in particular, clinical conditions.
Claus
Ralf A
RA
Department of Anesthesiology and Intensive Care Medicine, Division for Experimental Anesthesiology, Erlanger Allee 101, D-07747 Jena, Germany. ralf.claus@med.uni-jena.de
Bockmeyer
Clemens L
CL
Kentouche
Karim
K
Sieber
Matthias W
MW
Oberle
Volker
V
Kaufmann
Roland
R
Deigner
Hans-Peter
HP
Lösche
Wolfgang
W
D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; D000305:Adrenal Cortex Hormones / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001665:Binding Sites; D002460:Cell Line; D016572:Cyclosporine / Q000494:pharmacology; D018076:DNA, Complementary / Q000378:metabolism; D004318:Doxycycline / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology; D005091:Exons; D005786:Gene Expression Regulation; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D007249:Inflammation; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008666:Metalloendopeptidases / Q000096:biosynthesis* / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011697:Purpura, Thrombotic Thrombocytopenic / Q000097:blood; D012313:RNA / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013256:Steroids / Q000378:metabolism; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014841:von Willebrand Factor / Q000737:chemistry
D000305:Adrenal Cortex Hormones; D000900:Anti-Bacterial Agents; D018076:DNA, Complementary; D007166:Immunosuppressive Agents; D007375:Interleukin-1; D015850:Interleukin-6; D013256:Steroids; D014409:Tumor Necrosis Factor-alpha; D014841:von Willebrand Factor; D012313:RNA; D016572:Cyclosporine; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human; D004318:Doxycycline