Functional genomic study on atrial fibrillation using cDNA microarray and two-dimensional protein electrophoresis techniques and identification of the myosin regulatory light chain isoform reprogramming in atrial fibrillation.
BACKGROUND
Functional and structural changes of atrial tissue occur during the natural course of atrial fibrillation (AF), and these changes may contribute to further AF. We investigated the changes in AF tissue using cDNA microarray and two-dimensional protein electrophoresis techniques.


RESULTS
We established a porcine model of AF by rapid right atrial appendage pacing at a rate of 600/min. Atrial tissue was obtained after rapid atrial depolarization for 6 weeks. Microarrays containing 6,035 cDNA clones were used to evaluate the alterations of mRNA. Two-dimensional protein electrophoresis was performed to compare protein patterns. In cDNA microarray studies, we identified 387 genes with significant change in the left atrium and 81 genes in the right atrium. Among the genes, the ventricular isoform of the myosin regulatory light chain (MLC-2V) showed the greatest fold of change (9.4 and 7.3 in the left and right atrium, respectively). In protein electrophoresis, the expression levels of three protein spots spanning from 18 to 20 kDa in the acidic region (PI 4.5-5.0) were specifically elevated in the AF group. Interestingly, through tandem mass spectrometric analysis, these three spots were identified as MLC-2V. Thus, MLC-2V expression at the mRNA and protein levels corresponded well, and both indicated a significant increase in AF.


CONCLUSIONS
Both cDNA microarray and two-dimensional polyacrylamide protein electrophoresis studies revealed characteristic changes in AF tissue. We demonstrated the reprogramming of myosin regulatory light chain isoform composition, with a significant increase of its ventricular isoform (MLC-2V).
Lai
Ling-Ping
LP
Institute of Pharmacology, National Taiwan University, Taipei, Taiwan.
Lin
Jiunn-Lee
JL
Lin
Chich-Sheng
CS
Yeh
Huei-Ming
HM
Tsay
Yeou-Guang
YG
Lee
Chwen-Fang
CF
Lee
Hsiao-Hui
HH
Chang
Zee-Fen
ZF
Hwang
Juey-Jen
JJ
Su
Ming-Jai
MJ
Tseng
Yung-Zu
YZ
Huang
Shoei K Stephen
SK
D000818:Animals; D001281:Atrial Fibrillation / Q000235:genetics / Q000378:metabolism* / Q000628:therapy; D001483:Base Sequence; D002304:Cardiac Pacing, Artificial; D004195:Disease Models, Animal; D015180:Electrophoresis, Gel, Two-Dimensional; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000235:genetics; D015698:Genomic Library; D006325:Heart Atria / Q000378:metabolism / Q000601:surgery; D006329:Heart Conduction System / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D006352:Heart Ventricles / Q000378:metabolism / Q000601:surgery; D013058:Mass Spectrometry; D008955:Models, Cardiovascular; D008969:Molecular Sequence Data; D018994:Myosin Light Chains / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine
D018994:Myosin Light Chains; D020033:Protein Isoforms