| Summary: | 碩士 === 國立臺灣大學 === 分子與細胞生物學研究所 === 100 === Amiodarone, an anti-arrhythmia drug, stimulates s-vcanb over-expression at zebrafish embryonic heart, promotes cdh-5 over-expression by inhibited snail-1b at AV canal, and causes invagination of endicardial cell is block to form cardiac valve. However, the receptor and mechanism of s-vcanb affected endocardium invagination through cardiac jelly is still unknown. First, we inject large amount of dominant-negative form of s-vcanb (dn-s-vcanb) into embryo, over-expression of dn-s-vcanb embryos can not inhibit snail-1b expression in the heart field, whereas snail-1b and cdh-5 expression pattern are similar to wild-type; indicating S-vcanb in myocardial cell affects the expression of snail-1b and cdh-5 in endocardial cell by domain. When inject vcana MO, we found that snail-1b and cdh-5 expression in wild-type and Amiodarone-treated embryo was not affected by knockdown vcana. So, we prove that S-vcanb, but not vcana, via domain affect expression of downstream gene in endocardium. Next; Using receptor inhibitor, we found expression of snail-1b at AV canal was missing, and making cdh-5 over-expression, similar to Amiodarone-treated embryo and overexpression wild-type s-vcanb embryo. Therefore, we suggesting that Amiodarone induce over-expression of S-vcanb, then S-vcanb bind to receptor but inhibit receptor activity. Moreover, we found that phosphorylation of GSK3β was decresased in Amiodarone-treated embryo and receptor inhibitor-treated embryo; while Amiodaorone-treated embryo inject with s-vcanb MO, phosphorylation of GSK3β was not decreased; indicating Amiodarone inhibit receptor signaling by inducing s-vcanb over-expression, promoting GSK3β activity, and causing cdh-5 over-expression by suppressing snail-1b. Taken together, we concluded that Amiodarone induces s-vcanb overexpression at myocardium, Amiodarone stimulates S-vcanb overpression and inhibits receptor signaling, elevates GSK3β activity by decreasing its phosphorylation, and causes cdh-5 over-expression by inhibited snail-1b, with in turn, the invagination of endocardial cell is blocked, resulting defect of zebrafish cardiac valve.
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