Exacerbated vein graft arteriosclerosis in protein kinase Cδ–null mice
Michael Leitges, … , Yanhua Hu, Qingbo Xu
Michael Leitges, … , Yanhua Hu, Qingbo Xu
Published November 15, 2001
Citation Information: J Clin Invest. 2001;108(10):1505-1512. https://doi.org/10.1172/JCI12902.
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Article

Exacerbated vein graft arteriosclerosis in protein kinase Cδ–null mice

Abstract

Smooth muscle cell (SMC) accumulation is a key event in the development of atherosclerosis, including vein bypass graft arteriosclerosis. Because members of the protein kinase C (PKC) family signal cells to undergo proliferation, differentiation, or apoptosis, we generated PKCδ knockout mice and performed vein bypass grafts on these animals. PKCδ–/– mice developed normally and were fertile. Vein segments from PKCδ–/– mice isografted to carotid arteries of recipient mice of either genotype led to a more severe arteriosclerosis than was seen with PKCδ+/+ vein grafts. Arteriosclerotic lesions in PKCδ–/– mice showed a significantly higher number of SMCs than were found in wild-type animals; this was correlated with decreased SMC death in lesions of PKCδ–/– mice. SMCs derived from PKCδ–/– aortae were resistant to cell death induced by any of several stimuli, but they were similar to wild-type SMCs with respect to mitogen-stimulated cell proliferation in vitro. Furthermore, pro-apoptotic treatments led to diminished caspase-3 activation, poly(ADP-ribose) polymerase cleavage, and cytochrome c release in PKCδ–/– relative to wild-type SMCs, suggesting that their apoptotic resistance involves the loss of free radical generation and mitochondrial dysfunction in response to stress stimuli. Our data indicate that PKCδ maintains SMC homeostasis and that its function in the vessel wall per se is crucial in the development of vein graft arteriosclerosis.

Authors

Michael Leitges, Manuel Mayr, Ursula Braun, Ursula Mayr, Chaohong Li, Gerald Pfister, Nassim Ghaffari-Tabrizi, Gottfried Baier, Yanhua Hu, Qingbo Xu

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Figure 6

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Decreased apoptosis of PKCδ–/– SMCs (a). SMCs were treated with UV (10 J...
Decreased apoptosis of PKCδ–/– SMCs (a). SMCs were treated with UV (10 J/m2) and incubated for 7 hours; with TNF-α and IL-1β (50 ng/ml of each) for 36 hours; or with IL-1β and IFN-γ (50 ng/ml) or H2O2 (100 μm) for 36 hours. Then they were harvested and stained with annexin V–FITC and propidium iodide. Each panel represents an example of three independent experiments, and data on squares are means ± SD, *P < 0.05. (b) Western blot analysis. SMCs were treated with UV (10 J/m2), TNF-α (50 ng/ml), or H2O2 (100 μm) for 20 hours. Mitochondrial and cytosolic proteins were separately extracted and used for determining cytochrome c release (middle panel). Protein extracts from whole SMCs were used for analysis of PKCδ, cleaved caspase-3, PARP, and cytochrome c (lower panel). Data represent results of three similar experiments. Ctl, control. (c) SMCs were exposed to UV (10 J/m2) incubated for 7 hours or cytokines for 36 hours and analyzed with FACS after staining with JC-1. Red color represents mitochondria with high Δψ green color indicates low Δψ, and yellow is an intermediate phase. Note that both cell types coexist, but they differ in distribution.