Association between Serum Dickkopf-1 (DKK-1) Glycoprotein and Calcific Deposits on Cardiac Valves and Carotid Intimal-Medial Thickness in Hemodialysis Patients

2020 ◽  
Vol 10 (5) ◽  
pp. 313-322
Author(s):  
Dalia Younis ◽  
Ahmed Bahie ◽  
Rasha Elzehery ◽  
Ghada El-Kannishy ◽  
Ahmed M. Wahab
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Significant Negative Correlation ◽  
Negative Regulator ◽  
Intimal Medial Thickness ◽  
Carotid Intimal Medial Thickness ◽  
Cardiac Valve Calcification ◽  
Calcific Deposits ◽  
Score Range

Background: Cardiac valve calcification (CVC) is common in hemodialysis (HD) patients, and associated with cardiovascular and all-cause mortality. Once believed to be a passive process, it is now understood that the Wnt signaling pathway has a major role. The aim of the current study was to assess the relationship between circulating DKK-1, a negative regulator of the Wnt signaling pathway, and CVC, as well as carotid intimal-medial thickness (CIMT) in HD patients. Methods: We enrolled 74 consecutive adults on maintenance HD. Echocardiographic calcification of the mitral valve (MV) and aortic valve (AV) were detected according to Wilkins score (range 0–4), and the study of Tenenbaum et al. [Int J Cardiol. 2004 Mar;94(1):7–13] (range 0–4), respectively. CVC severity was calculated by a supposed score (range 0–8) that represents the sum of calcification grade of MV and AV. CVC severity was classified into absent (CVC score = 0), mild (CVC score = 1–2), moderate (CVC score = 3–4), and severe (CVC score ≥5). Demographic and biochemical data were collected in addition to serum DKK-1 levels and CIMT. Results: CVC was present in 67 patients (91.0%). There was a highly significant negative correlation between serum DKK-1 level and CVC score (r = –0.492; p ≤ 0.001), as well as CIMT (r = –0.611; p ≤ 0.001). Age and CIMT were independent determinants of CVC. Conclusions: CVC is almost present in all HD patients. DKK-1 seems to have a direct relation with CVC and CIMT in HD patients. Age is the strongest independent determinant of CVC.

scholarly journals The microRNA miR-8 is a conserved negative regulator of Wnt signaling

2008 ◽  
Vol 105 (40) ◽  
pp. 15417-15422 ◽  
Author(s):  
Jennifer A. Kennell ◽  
Isabelle Gerin ◽  
Ormond A. MacDougald ◽  
Ken M. Cadigan
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Target Genes ◽  
Wnt Signaling Pathway ◽  
Negative Regulator ◽  
Animal Development ◽  
Protein Levels ◽  
Evolutionarily Conserved ◽  
Multiple Levels

Wnt signaling plays many important roles in animal development. This evolutionarily conserved signaling pathway is highly regulated at all levels. To identify regulators of the Wnt/Wingless (Wg) pathway, we performed a genetic screen in Drosophila. We identified the microRNA miR-8 as an inhibitor of Wg signaling. Expression of miR-8 potently antagonizes Wg signaling in vivo, in part by directly targeting wntless, a gene required for Wg secretion. In addition, miR-8 inhibits the pathway downstream of the Wg signal by repressing TCF protein levels. Another positive regulator of the pathway, CG32767, is also targeted by miR-8. Our data suggest that miR-8 potently antagonizes the Wg pathway at multiple levels, from secretion of the ligand to transcription of target genes. In addition, mammalian homologues of miR-8 promote adipogenesis of marrow stromal cells by inhibiting Wnt signaling. These findings indicate that miR-8 family members play an evolutionarily conserved role in regulating the Wnt signaling pathway.

scholarly journals Wnt/β-Catenin/Tcf Signaling Induces the Transcription of Axin2, a Negative Regulator of the Signaling Pathway

2002 ◽  
Vol 22 (4) ◽  
pp. 1172-1183 ◽  
Author(s):  
Eek-hoon Jho ◽  
Tong Zhang ◽  
Claire Domon ◽  
Choun-Ki Joo ◽  
Jean-Noel Freund ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Pathway ◽  
Genomic Sequence ◽  
Wnt Signaling Pathway ◽  
Genomic Region ◽  
Negative Regulator ◽  
Mobility Shift ◽  
Specific Expression

ABSTRACT Axin2/Conductin/Axil and its ortholog Axin are negative regulators of the Wnt signaling pathway, which promote the phosphorylation and degradation of β-catenin. While Axin is expressed ubiquitously, Axin2 mRNA was seen in a restricted pattern during mouse embryogenesis and organogenesis. Because many sites of Axin2 expression overlapped with those of several Wnt genes, we tested whether Axin2 was induced by Wnt signaling. Endogenous Axin2 mRNA and protein expression could be rapidly induced by activation of the Wnt pathway, and Axin2 reporter constructs, containing a 5.6-kb DNA fragment including the promoter and first intron, were also induced. This genomic region contains eight Tcf/LEF consensus binding sites, five of which are located within longer, highly conserved noncoding sequences. The mutation or deletion of these Tcf/LEF sites greatly diminished induction by β-catenin, and mutation of the Tcf/LEF site T2 abolished protein binding in an electrophoretic mobility shift assay. These results strongly suggest that Axin2 is a direct target of the Wnt pathway, mediated through Tcf/LEF factors. The 5.6-kb genomic sequence was sufficient to direct the tissue-specific expression of d2EGFP in transgenic embryos, consistent with a role for the Tcf/LEF sites and surrounding conserved sequences in the in vivo expression pattern of Axin2. Our results suggest that Axin2 participates in a negative feedback loop, which could serve to limit the duration or intensity of a Wnt-initiated signal.

scholarly journals A divergent canonical WNT-signaling pathway regulates microtubule dynamics

2004 ◽  
Vol 164 (2) ◽  
pp. 243-253 ◽  
Author(s):  
Lorenza Ciani ◽  
Olga Krylova ◽  
Matthew J. Smalley ◽  
Trevor C. Dale ◽  
Patricia C. Salinas
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Transcriptional Activation ◽  
Glycogen Synthase ◽  
Wnt Signaling Pathway ◽  
Negative Regulator ◽  
Canonical Wnt Signaling ◽  
Microtubule Stability ◽  
Gsk 3Β ◽  
Canonical Wnt

Dishevelled (DVL) is associated with axonal microtubules and regulates microtubule stability through the inhibition of the serine/threonine kinase, glycogen synthase kinase 3β (GSK-3β). In the canonical WNT pathway, the negative regulator Axin forms a complex with β-catenin and GSK-3β, resulting in β-catenin degradation. Inhibition of GSK-3β by DVL increases β-catenin stability and TCF transcriptional activation. Here, we show that Axin associates with microtubules and unexpectedly stabilizes microtubules through DVL. In turn, DVL stabilizes microtubules by inhibiting GSK-3β through a transcription- and β-catenin–independent pathway. More importantly, axonal microtubules are stabilized after DVL localizes to axons. Increased microtubule stability is correlated with a decrease in GSK-3β–mediated phosphorylation of MAP-1B. We propose a model in which Axin, through DVL, stabilizes microtubules by inhibiting a pool of GSK-3β, resulting in local changes in the phosphorylation of cellular targets. Our data indicate a bifurcation in the so-called canonical WNT-signaling pathway to regulate microtubule stability.

scholarly journals Carboxypeptidase E: a negative regulator of the canonical Wnt signaling pathway

Oncogene ◽  
2012 ◽  
Vol 32 (23) ◽  
pp. 2836-2847 ◽  
Author(s):  
N Skalka ◽  
M Caspi ◽  
E Caspi ◽  
Y P Loh ◽  
R Rosin-Arbesfeld
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Negative Regulator ◽  
Canonical Wnt Signaling ◽  
Carboxypeptidase E ◽  
Canonical Wnt

scholarly journals Fas-associated factor 1 antagonizes Wnt signaling by promoting β-catenin degradation

2011 ◽  
Vol 22 (9) ◽  
pp. 1617-1624 ◽  
Author(s):  
Long Zhang ◽  
Fangfang Zhou ◽  
Theo van Laar ◽  
Juan Zhang ◽  
Hans van Dam ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Glycogen Synthase ◽  
Ectopic Expression ◽  
Wnt Signaling Pathway ◽  
Negative Regulator ◽  
Associated Factor ◽  
Functional Studies ◽  
Cell Proliferation And Differentiation ◽  
Canonical Wnt

The canonical Wnt pathway plays an important role in the regulation of cell proliferation and differentiation. Activation of this signaling pathway causes disruption of the Axin/adenomatous polyposis coli/glycogen synthase kinase 3β complex, resulting in stabilization of β-catenin and its association with lymphoid enhancer factor/T-cell factor in the nucleus. Here, we identify Fas-associated factor 1 (FAF1) as a negative regulator of Wnt/β-catenin signaling. We found overexpression of FAF1 to strongly inhibit Wnt-induced transcriptional reporter activity and to counteract Wnt-induced β-catenin accumulation. Moreover, knockdown of FAF1 resulted in an increase in β-catenin levels and in activation of Wnt/β-catenin–induced transcription. FAF1 was found to interact with β-catenin upon inhibition of proteasome. Ectopic expression of FAF1 promoted β-catenin degradation by enhancing its polyubiquitination. Functional studies in C2C12 myoblasts and KS483 preosteoblastic cells showed that FAF1 depletion resulted in activation of endogenous Wnt-induced genes and enhanced osteoblast differentiation, whereas FAF1 overexpression had the opposite effect. These results identify FAF1 as a novel inhibitory factor of canonical Wnt signaling pathway.

scholarly journals WID, a novel negative regulator of the WNT signaling pathway, is important for kidney development

2009 ◽  
Vol 331 (2) ◽  
pp. 484
Author(s):  
Myong Shin Kim ◽  
Jirouta Kitagaki ◽  
Frank Bollig ◽  
Christoph Englert ◽  
Alan O. Perantoni ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Kidney Development ◽  
Wnt Signaling Pathway ◽  
Negative Regulator
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