LY290181, an Inhibitor of Diabetes-Induced Vascular Dysfunction, Blocks Protein Kinase C—Stimulated Transcriptional Activation Through Inhibition of Transcription Factor Binding to a Phorbol Response Element

Abstract

Previous studies have shown that high glucose levels and diabetes induce an elevation in protein kinase C (PKC) activity in vascular cells and tissues susceptible to diabetic complications. In addition, PKC activation has been shown to modulate vascular cell growth, permeability, and gene expression, processes thought to be involved in the development of vascular complications. Using two in vivo model systems, we have identified a novel inhibitor of diabetic vascular dysfunction, LY290181. LY290181 prevented glucose-induced increases in blood flow and permeability in rat granulation tissue and corresponding vascular changes in the retina, sciatic nerve, and aorta of diabetic rats. Tested for its ability to inhibit PKC-regulated processes, LY290181 inhibited phorbol ester-stimulated plasminogen activator activity in a dose-dependent manner in bovine retinal endothelial cells and in human dermal fibroblasts. In addition, LY290181 inhibited phorbol ester-stimulated activation of the porcine urokinase plasminogen activator (uPA) promoter (-4600/+398) linked to the chloramphenicol acetyltransferase (CAT) reporter gene (p4660CAT). More detailed analysis of the uPA promoter revealed that LY290181 inhibited phorbol ester-stimulated activation of the uPA phorbol response element (-2458/-2349) located upstream of the thymidine kinase promoter (puPATKCAT). LY290181 appears to inhibit uPA promoter activation by blocking phorbol ester-stimulated binding of nuclear proteins to the uPA PEA3/12-0-tetradecanoylphorbol 13-acetate responsive element (TRE). These results suggest that LY290181 may inhibit diabetes-induced vascular dysfunction by inhibiting transcription factor binding to specific PKC-regulated genes involved in vascular function.

Dysfunction of the endothelial nitric oxide signalling pathway in diabetes and hyperglycaemia

“…1 and ,/2 isoforms of PKC by the novel inhibitor LY333531 ameliorates the elevated glomerular filtration rates, albumin excretion rates and dysfunction of the retinal circulation in diabetic rats (Ishii, Jirousek, Koya, Takagi, Xia, Clermont, Bursell, Kern, Ballas, Heath, Stramm, Feener & . LY290181 is another inhibitor of PKC activation, which has been shown to prevent glucose-induced changes in the retina, sciatic nerve and aorta of diabetic rats (Birch, Heath, Hermeling, Johnston, Stramm, Dell, Smith, Williamson & Reifelmiller, 1996). Vasodilatation in response to ADP, acetylcholine or histamine has been found to be impaired during application of 20 and 25mM D-glucose in rat cerebral arterioles, an effect reversed by the PKC inhibitors calphostin C or chelerythrine (Mayhan & Patel, 1995).…”

Comprehensive morphological peculiarities of blood polymorphonuclear neutrophil granulocytes under experimental diabetes mellitus

“…Порівнюючи отримані дані за мов ЕЦД з онтрольними значеннями, можна ствердж вати, що при діабеті пор ш ються ре ляторні можливості мембран нейтрофілів зв'яз зі зміною осмолярності вн трішньо о середовища, я а з мовлена висо ою онцентрацією лю ози рові [16,18,21,23]. За мов стрептозотоциново о діабет введення L-ар інін і аміно анідин приводило до поліпшення осморе ляторно о стат с літинних мембран порівняно з діабетом (рис.…”

Basic and Clinical Aspects of Gene Therapy for Retinopathy Induced by Diabetes

“…For example, PKC inhibition ameliorates glucose-induced endothelial dysfunction [Booth et al, 2002] and VEGF over-expression [Frank, 2002]. Therefore, gene therapy targeted at PKC inhibition, such as by PKC anti-sense oligonucleotide may be one approach to prevent neovascularisation and endothelial dysfunction [Birch et al, 1996]. Therefore, gene therapy targeted at PKC inhibition, such as by PKC anti-sense oligonucleotide may be one approach to prevent neovascularisation and endothelial dysfunction [Birch et al, 1996].…”