Human C-reactive protein slows atherosclerosis development in a mouse model with human-like hypercholesterolemia - PubMed (original) (raw)

Human C-reactive protein slows atherosclerosis development in a mouse model with human-like hypercholesterolemia

Alexander Kovacs et al. Proc Natl Acad Sci U S A. 2007.

Abstract

Increased baseline values of the acute-phase reactant C-reactive protein (CRP) are significantly associated with future cardiovascular disease, and some in vitro studies have claimed that human CRP (hCRP) has proatherogenic effects. in vivo studies in apolipoprotein E-deficient mouse models, however, have given conflicting results. We bred atherosclerosis-prone mice (Apob(100/100)Ldlr(-/-)), which have human-like hypercholesterolemia, with hCRP transgenic mice (hCRP(+/0)) and studied lesion development at 15, 30, 40, and 50 weeks of age. Atherosclerotic lesions were smaller in hCRP(+/0)Apob(100/100)Ldlr(-/-) mice than in hCRP(0/0)Apob(100/100)Ldlr(-/-) controls, as judged from the lesion surface areas of pinned-out aortas from mice at 40 and 50 weeks of age. In lesions from 40-week-old mice, mRNA expression levels of several genes in the proteasome degradation pathway were higher in hCRP(+/0)Apob(100/100)Ldlr(-/-) mice than in littermate controls, as shown by global gene expression profiles. These results were confirmed by real-time PCR, which also indicated that the activities of those genes were the same at 30 and 40 weeks in hCRP(+/0)Apob(100/100)Ldlr(-/-) mice but were significantly lower at 40 weeks than at 30 weeks in controls. Our results show that hCRP is not proatherogenic but instead slows atherogenesis, possibly through proteasome-mediated protein degradation.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.

Fig. 1.

Atherosclerosis development in _LDlr_−/−_Apob_100/100 mice with and without hCRP expression. (A) Sudan IV-stained atherosclerotic lesions in pinned-out aortas (Upper) and aortic arches of the same aortas (Lower) from representative mice in both groups. (B) Lesion surface area is reported as the area of Sudan IV staining, expressed as percentage of the entire surface area of the aorta from the iliac bifurcation to the aortic root. n = 17 CRP+/0_Ldlr_−/−_Apob_100/100 mice (filled bars) and 19 controls (open bars) at 30 weeks; n = 13 and 10 at 40 weeks; n = 11 and 15 at 50 weeks. Values are mean ± SD. †, P = 0.027 (40 weeks); *, P = 0.041 (50 weeks) vs. control mice. N.D., not detectable.

Fig. 2.

Fig. 2.

Atherosclerosis histology of _Ldlr_−/−_Apob_100/100 mice with and without hCRP expression. (A) Immunofluorescence staining for CRP, C3, and CD68 in aortic root sections from CRP+/0_Ldlr_−/−_Apob_100/100 mice and _CRP_0/0_Ldlr_−/−_Apob_100/100 controls. Sections were incubated with primary antibodies and then with fluorescently labeled anti-rat IgG and counterstained with DAPI. (B) Aortic root sections stained with Masson's trichrome (collagen) and Oil Red O (lipids) from representative mice in both groups. Except for focal C3 staining in controls at 40 and 50 weeks and ≈10% more collagen in lesions of CRP+/0_Ldlr_−/−_Apob_100/100 at 50 weeks (n = 5 + 5; P < 0.05), there were no other differences between groups.

Fig. 3.

Fig. 3.

Global gene expression analysis and real-time PCR of mRNA isolated from the arterial wall in the aortic arch, including the atherosclerotic lesions (see Materials and Methods) of mice at 30 and 40 weeks of age. (A) Pie charts of Gene Ontology categories (biological processes, molecular functions, and cellular component) and Kegg pathways generated from 742 differentially expressed genes (LFDR < 0.25;

SI Table 2

). The P values next to each category were calculated with Fisher's exact probability test (

SI Appendix 1

). (B) Heat map showing mRNA levels (blue, low; red, high) of genes (rows) in the proteasome degradation pathway, which was highly active in the CRP+/0_Ldlr_−/−_Apob_100/100 mice compared with the controls (LFDR < 0.09), as shown by gene set enrichment analysis of the same GeneChips. Gene names marked in green were chosen for real-time PCR analysis. (C) mRNA levels of six genes central to proteasome degradation (PSMA7, PSMB7, PSMB9, PSMC6, PSME2, and UBE2D3) determined by real-time PCR of total RNA from aortic arch lesions in CRP+/0_Ldlr_−/−_Apob_100/100 mice (filled bars) and _CRP_−/−_Ldlr_−/−_Apob_100/100 controls (open bars) at 30 weeks (n = 5 and n = 7, respectively) and 40 weeks (n = 8 per group). Values are mean ± SD. *, P < 0.02; †, P < 0.006; ‡, P < 0.02; §, P < 0.05; ‖, P < 0.006; #, P < 0.004 vs. controls at 30 weeks.

Similar articles

Cited by

References

    1. Danesh J, Wheeler JG, Hirschfield GM, Eda S, Eiriksdottir G, Rumley A, Lowe GD, Pepys MB, Gudnason V. N Engl J Med. 2004;350:1387–1397. - PubMed
    1. Ridker PM, Wilson PWF, Grundy SM. Circulation. 2004;109:2818–2825. - PubMed
    1. Jialal I, Devaraj S, Venugopal SK. Hypertension. 2004;44:6–11. - PubMed
    1. Plump AS, Smith JD, Hayek T, Aalto-Setala K, Walsh A, Verstuyft JG, Rubin EM, Breslow JL. Cell. 1992;71:343–353. - PubMed
    1. Hirschfield GM, Gallimore JR, Kahan MC, Hutchinson WL, Sabin CA, Benson GM, Dhillon AP, Tennent GA, Pepys MB. Proc Natl Acad Sci USA. 2005;102:8309–8314. - PMC - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources