Phospholipase Cbeta4 isozyme is expressed in human, rat, and murine heart left ventricles and in HL-1 cardiomyocytes.
Phospholipase C-beta (PLCbeta) isozymes (PLCbeta(1) and PLCbeta(3)) have been extensively characterized in cardiac tissue, but no data are available for the PLCbeta(4) isozyme. In this study, PLCbeta((1-4)) isozymes mRNA relative expression was studied by real-time PCR (RT-PCR) in human, rat, and murine left ventricle and the presence of PLCbeta(4) isozyme at the protein level was confirmed by Western blotting in all species studied. Confocal microscopy experiments carried out in HL-1 cardiomyocytes revealed a sarcoplasmic subcellular distribution of PLCbeta(4). Although there were unexpected significant interspecies differences in the PLCbeta((1-4)) mRNA expression, PLCbeta(4) mRNA was the main transcript expressed in all left ventricles studied. Thus, whereas in human and rat left ventricles PLCbeta(4) > PLCbeta(3) > PLCbeta(2) > PLCbeta(1) mRNA pattern of expression was found, in murine left ventricle the pattern of expression was different, i.e., PLCbeta(4) > PLCbeta(1) > PLCbeta(3) > PLCbeta(2). However, results obtained in mouse HL-1 cardiomyocytes showed PLCbeta(3) approximately PLCbeta(4) > PLCbeta(1) > PLCbeta(2) pattern of mRNA expression indicating a probable cell type specific expression of the different PLCbeta isozymes in cardiomyocytes. Finally, RT-PCR experiments showed a trend, even though not significant (P = 0.067), to increase PLCbeta(4) mRNA levels in HL-1 cardiomyocytes after angiotensin II treatment. These results demonstrate the presence of PLCbeta(4) in the heart and in HL-1 cardiomyocytes showing a different species-dependent pattern of expression of the PLCbeta((1-4)) transcripts. We discuss the relevance of these findings in relation to the development of cardiac hypertrophy.
Experimental Unit, Hospital Donostia, San Sebastián, Spain.
David
D
Otaegui
Ramón
R
Querejeta
Ander
A
Arrieta
Ane
A
Lazkano
Angel
A
Bidaurrazaga
Jose Ramón
JR
Arriandiaga
Pablo
P
Aldazabal
Mikel Asier
MA
Garro
D000328:Adult; D000818:Animals; D002460:Cell Line; D015870:Gene Expression; D015971:Gene Expression Regulation, Enzymologic; D006352:Heart Ventricles / Q000378:metabolism*; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D032383:Myocytes, Cardiac / Q000378:metabolism*; D054799:Phospholipase C beta / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D011921:Rats, Inbred WKY; D013045:Species Specificity
D007527:Isoenzymes; D054799:Phospholipase C beta