Isozymic changes in myosin of human atrial myocardium induced by overload. Immunohistochemical study using monoclonal antibodies.

Tsuchimochi, Hidetsugu; Sugi, Masahito; Kuro‐o, Makoto; Ueda, Seigo; Takaku, Fumimaro; Furuta, Shunsuke; Shirai, Toshikazu; Yazaki, Yoshio

doi:10.1172/jci111466

Cited by 83 publications

(36 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…We reported the isozymic redistribution in human atria by pressure overload, that is, HCa, a predominant myosin isozyme in the atrium was replaced by lI in atria subjected to pressure overload. The extent of isozymic change correlated well with atrial pressure (10). Here, we observed a similar increment of (2 in pressure-overloaded atria.…”

Section: Resultssupporting

confidence: 85%

“…In a previous report, we showed that a redistribution of isozymes from HCa to HCB (,B) can occur by pressure overload even in the human atrial myocardium (10). In this study, we examined whether #2 showed a change similar to #I by pressure overload.…”

Section: Discussionmentioning

confidence: 90%

“…Their distribution in normal human hearts and redistribution in pressureoverloaded atria were characteristic to p3-type myosin isozyme (10,31 In adult human hearts, HCa was expressed in almost all atrial myofibers and in a few ventricular myofibers. In contrast, #I and #2 might coexist in all ventricular myofibers and also exist in some myofibers of the atrium, where, however, they were not necessarily expressed simultaneously in individual myofibers.…”

Section: Discussionmentioning

confidence: 95%

“…MoAbs specific for HCa and HCft were produced by fusion ofisolated spleen cells from mice immunized by myosins purified from bovine atria and human ventricles, respectively, with myeloma cell lines (P3U ) (10). Antimyosin activity in the medium from hybridoma colonies was screened by ELISA according to Guesdon et al (19), as described previously (10,11).…”

Section: Methodsmentioning

confidence: 99%

“…We calculated the percentage of myofibers reacted with a MoAb as P (%) + S (%) by counting more than 1,000 myofibers. As for quantification, total scores were calculated, scoring one S fiber as one, one P fiber as 0.5, and one pseudonegative or completely negative fiber as 0, as described previously (10). Thus, the percentage of myofibers reactive with a MoAb and the total scores per 1,000 myofibers were calculated in each specimen.…”

Section: Methodsmentioning

confidence: 99%

See 4 more Smart Citations

Heterogeneity of beta-type myosin isozymes in the human heart and regulational mechanisms in their expression. Immunohistochemical study using monoclonal antibodies.

et al. 1988

Self Cite

View full text Add to dashboard Cite

To investigate the existence of heterogeneity of j-type myosin isozymes (HC,6) in human hearts, immunohistochemical studies using monoclonal antibodies (MoAbs) raised against human ventricular myosin heavy chains were performed. Two types of MoAbs recognized some muscle fibers in the atrium, whereas both reacted with all ventricular muscle fibers. Since atrial muscle fibers reactive with each MoAb were found to be clearly different, the existence of two immunologically distinct HCQ (AI, and 2) was suggested in the atrium. By using affinity chromatography, two molecular variants of HC# were isolated from the bovine atrium, and differences in the primary structure of 8 and 2 were confirmed by analysis of peptides produced by chymotriptic digestion. In pressure-overloaded human atria, myofibers containing fai and/or 2 increased in accordance with decrement of myofibers containing a-type myosin isozyme (P < 0.01). But they differed in expression during the developmental stage, since 2 did not exist in the early embryonic bovine heart, but t, did. Thus, there are two distinct HCQ whose expression is regulated by at least two factors: pressure overload and developmental stage.

show abstract

Section: Resultssupporting

confidence: 85%

Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Heterogeneity of beta-type myosin isozymes in the human heart and regulational mechanisms in their expression. Immunohistochemical study using monoclonal antibodies.

et al. 1988

Self Cite

View full text Add to dashboard Cite

show abstract

Intracellular assembly of newly synthesized canine cardiac myosins

Seko

Naito

Imataka

et al. 1990

Cell Biochemistry & Function

View full text Add to dashboard Cite

To investigate how newly synthesized cardiac myosins are assembled into myofilaments, we analysed the distribution of newly produced alpha-myosin heavy chain isozyme in sarcomeres by immunoelectron microscopy using a monoclonal antibody (CMA19), which is specific for alpha-myosin heavy chain. Isozymic changes in myosin heavy chains from beta to alpha type were induced in canine ventricular muscles and cultured ventricular myocytes by administration of 1-thyroxine. We incubated the glycerinated ventricular muscles or cultured ventricular myocytes with the enzyme (horseradish peroxidase) labelled Fab fragment of CMA19. After the reaction with 3, 3'-diaminobenzidine and osmification, we prepared ultrathin sections of the ventricular muscles or cultured ventricular myocytes and analysed their staining patterns by electron microscopy. There was apparent heterogeneity in the staining intensity of the myofilaments among different cells, among different myofibrils and even intramyofibrillarly. Higher magnification revealed that there were scattered foci of strong reaction which appeared to be foci of assembly of the newly synthesized alpha-myosin heavy chain. Immunocytochemical study also showed heterogeneous reactions within myofilaments and that there were scattered foci of myofilament assembly, which were closely associated with polyribosomes producing newly induced alpha-myosin heavy chain. These data suggest that newly synthesized cardiac myosins are assembled into myofilaments from the sites of synthesis, that is polyribosomes. This may explain the heterogeneity of the assembly pattern of newly synthesized cardiac myosins at the subcellular level.

show abstract