Gene expression and atrial natriuretic factor processing and secretion in cultured AT-1 cardiac myocytes.
BACKGROUND
Studies were carried out to characterize several biochemical features of cultured AT-1 cells.


RESULTS
These cells were obtained from a transplantable atrial cardiomyocyte tumor lineage. Reverse transcriptase-polymerase chain reaction-based analyses demonstrated that the pattern of gene expression of cultured AT-1 cells was similar to that of adult atrial myocytes. AT-1 cells expressed atrial natriuretic factor (ANF), alpha-cardiac myosin heavy chain, alpha-cardiac actin, and connexin43. Radioimmunoassays verified that the cells synthesized, stored, and secreted ANF. Through size-exclusion, reversed-phase, and carboxymethyl-ion-exchange high-performance liquid chromatography, it was shown that cultured AT-1 cells stored ANF as pro-ANF (ANF-[1-126]), which was cosecretionally processed quantitatively to ANF-(1-98) and the bioactive 28-amino-acid ANF-(99-126). In addition, cultured AT-1 cells secreted ANF at almost a sixfold greater rate in response to endothelin-1, a potent secretagogue of ANF. KCl, metenkephalinamide, isoproterenol, phenylephrine, and 12-O-tetradecanoyl-phorbol-13-acetate also stimulated ANF release.


CONCLUSIONS
These studies, in combination with previous findings, demonstrated that cultured AT-1 cells, while maintaining the ability to proliferate, have retained functional, biochemical, and ultrastructural features that are characteristic of adult atrial myocytes.
Lanson
N A
NA
Department of Biochemistry and Molecular Biology, Louisiana State University Medical Center, New Orleans 70112.
Glembotski
C C
CC
Steinhelper
M E
ME
Field
L J
LJ
Claycomb
W C
WC
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000235:genetics / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D017630:Connexins; D003285:Contractile Proteins / Q000378:metabolism; D015870:Gene Expression; D006321:Heart / Q000502:physiology*; D007536:Isomerism; D008565:Membrane Proteins / Q000235:genetics; D008968:Molecular Conformation; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D016133:Polymerase Chain Reaction; D011863:Radioimmunoassay; D014407:Tumor Cells, Cultured
D017630:Connexins; D003285:Contractile Proteins; D008565:Membrane Proteins; D009320:Atrial Natriuretic Factor