Expression of protein kinase C isoforms in smooth muscle cells in various states of differentiation

Abstract

We analysed the expression of protein kinase C (PKC) isoforms in smooth muscle cells (SMC) in various states of differentiation, using Western blots and thermocycle amplification of mRNA. SMC isolated from intact tissues express three isoforms of PKC, namely a, 6, and c. Following cell culture, SMC additionally express mRNA for PKC-E, but significant amounts of the corresponding protein were not detected. Transformed SMC, such as the cell line DDT, MF-2, express both mRNA and protein for PKC-E, lack the 6 isoenyzme, whilst maintaining the expression of the a and < isoforms. Thus PKCd and E isoenzyme expression appears to vary with the state of differentiation of these cells, with PKC-E expression increasing as the cells become proliferative.

UDP acts as a growth factor for vascular smooth muscle cells by activation of P2Y6receptors

“…With the use of Western blots and RT-PCR, PKC-␣, -␦, -, and -⑀ isoforms were detected in smooth muscle cells, but their expression varied in various states of differentiation (3). Because the general PKC downregulator PMA specifically inhibited the mitogenic response, whereas the inhibitors of PKC-␣, -, and -⑀ were without effect, it is possible that UDP acts via PKC-␦ to transmit signal to the nucleus.…”

Phenotypic diversity and molecular mechanisms of airway smooth muscle proliferation in asthma

“…ASSENDER et al [116] reported that nonproliferating human and rat vascular smooth muscle cells showed a similar qualitative pattern of PKC isoform expression (a-, d-and f-PKC) to proliferating smooth muscle cells in culture. Analysis of the messenger ribonucleic acid (mRNA), however, revealed that, unlike their proliferating counterparts, quiescent smooth muscle cells did not express mRNA for PKCe.…”

“…In contrast, PKCd, a Ca 2+ -independent PKC isoform also expressed in airway smooth muscle, has previously been shown to retard cell cycle progression in G 1 through an effect on cell cyclins [122], suggesting that activation of different PKC isoforms in smooth muscle may lead either to growth acceleration or inhibition. ASSENDER et al [116], using Western immunoblot analyses, reported that PKCf expression was present in both proliferating and contractile rat vascular smooth muscle cells. A study examining PKCf activity in chicken gizzard smooth muscle suggests that this isoform differs very markedly from other PKC isoforms in its susceptibility to downregulation by phorbol esters and in its inhibition by PKC inhibitors such as sphingosine, chelerythrine, staurosporine or calphostin C [123].…”

Hypoxic Pulmonary Arterial Hypertension in the Chicken Model

“…Although little is known about the pathogenesis of remodeling in hypertensive broilers, evidence is emerging that there is reduced apoptosis in vascular smooth muscle cells (Tan et al, 2005a) and increased expression of protein kinase C (Tan et al, 2005b), a key enzyme in promoting the proliferation and differentiation of vascular smooth muscle cells and nonmuscle cells (Assender et al, 1994;Haller et al, 1995;Wang et al, 1997;Fleming et al, 1998). Additionally, using an immunohistochemical technique, Ozyigit et al (2005) found that the expression of matrix metalloproteinase (MMP)-2, MMP-9 and tissue inhibitors of metalloproteinase (TIMP)-1 were increased in the lung of broilers with salt-induced PHS, and that MMP-2 was localized mainly in pulmonary vascular endothelium whereas TIMP-1 was localized in the adventitia.…”