A Role for the Extracellular Signal-regulated Kinase and p38 Mitogen-activated Protein Kinases in Interleukin-1β-stimulated Delayed Signal Tranducer and Activator of Transcription 3 Activation, Atrial Natriuretic Factor Expression, and Cardiac Myocyte Morphology

Abstract

We have demonstrated that two hypertrophic agents, interleukin-1␤ (IL-1␤) and leukemic inhibitory factor (LIF), altered cardiac myocyte morphology with striking similarity and prompted us to investigate the common actions of these cytokines. We compared the phospho-

Identification of the Critical Features of a Small Peptide Inhibitor of JNK Activity

“…ERK1 and ERK2, rather than simply ERK2 alone, or different JNK isoforms rather than JNK1 alone) rather than each single protein kinase isoform in isolation. Thus, we prepared ventricular myocytes from the hearts of 1-2-day-old Sprague-Dawley rats (25). These myocytes were seeded at a density of 4 ϫ 10 6 cells per gelatin-coated, 60-mm tissue culture dish and cultured for 24 h before overnight incubation in serum-free medium.…”

“…Following stimulation, cells were lysed in ice-cold Buffer A, and measurements of total protein in each lysate were made. For measurement of JNK activity, 100 g of control and sorbitol-stimulated lysates were incubated with 20 g of GST-cJun-(1-135) (25). For measurement of ERK activity, 100 g of lysates from control, TPA-, PD98059-, and TPA ϩ PD98059-treated cells were incubated with 20 g of GST-Elk-(307-428) (25).…”

“…For measurement of JNK activity, 100 g of control and sorbitol-stimulated lysates were incubated with 20 g of GST-cJun-(1-135) (25). For measurement of ERK activity, 100 g of lysates from control, TPA-, PD98059-, and TPA ϩ PD98059-treated cells were incubated with 20 g of GST-Elk-(307-428) (25). For measurement of p38 activity, 600 g of lysates from control and arsenite-stimulated cells were incubated with 40 g of GST-MAPK-activated protein kinase-2 (MAPKAPK2-(46 -400)).…”

Myoseverin disrupts sarcomeric organization in myocytes: An effect independent of microtubule assembly inhibition

“…Neonatal cardiac myocytes were isolated from the hearts of 1-to 2-day-old Sprague-Dawley rats as previously described [Ng et al, 2001]. Briefly, ventricular cells were isolated by collagenase treatment and then preplated to deplete the culture of non-myocytes.…”

“…Firstly, we sought to confirm that similar cytoske-letal reorganization occurred in the neonatal cardiac myocytes. These cells exhibit increased sarcomere assembly and reorganization in response to hypertrophic agonist treatment such as the a-adrenergic coupled receptor agonist, PE, or the IL-6 family cytokine, LIF [Aoki et al, 1998;Ng et al, 2001]. In Fig.…”