Objective. The effects of C-reactive protein (CRP) and tumor necrosis factor-α (TNF-α) on pregnancy-associated plasma protein-A (PAPP-A) expression in human peripheral blood mononuclear cells (PBMCs) require further investigation. Methods. The PAPP-A levels in culture supernatants, PAPP-A mRNA expression, and cellular PAPP-A expression were measured in human PBMCs isolated from fresh blood donations provided by 6 healthy volunteers (4 donations per volunteer). Analyses were conducted by ultrasensitive ELISA, western blotting, and RT-PCR following stimulation with CRP or TNF-α cytokines. Results. PAPP-A mRNA and protein levels after CRP stimulation peaked at 24 hours, whereas peak PAPP-A mRNA and protein levels were achieved after TNF-α stimulation at only 2 and 8 hours, respectively. These findings indicate the dose-dependent effect of CRP and TNF-α stimulation. Actinomycin D treatment completely prevented CRP and TNF-α induction of PAPP-A mRNA and protein expression. Additionally, nuclear factor- (NF-) κB inhibitor (BAY11-7082) potently inhibited both CRP and TNF-α stimulated PAPP-A mRNA and protein expression. Conclusions. Human PBMCs are capable of expressing PAPP-A in vitro, expression that may be regulated by CRP and TNF-α through the NF-κB pathway. This mechanism may play a significant role in the observed increase of serum PAPP-A levels in acute coronary syndrome (ACS). 1. Introduction Pregnancy-associated plasma protein-A (PAPP-A) is a metzincin metalloproteinase primarily produced by the placental syncytiotrophoblast during pregnancy. PAPP-A is also synthesized by fibroblasts, osteoblasts, vascular smooth muscle cells (VSMCs), and endothelial cells (ECs). In vitro, PAPP-A functions to cleave insulin-like growth factor-binding protein 4 (IGFBP-4), an inhibitory IGFBP, consequently increasing IGF bioavailability for receptor activation [1–4]. In vivo, several studies have shown a similar role for PAPP-A in modulating site- and event-specific IGF signaling during injury repair processes [2]. Recent studies have indicated that PAPP-A is a novel biomarker for plaque instability and inflammation useful in early diagnosis, risk stratification, and prognostic prediction in patients with acute coronary syndrome (ACS) [5, 6]. PAPP-A was found abundantly expressed in ruptured and eroded human atherosclerotic plaques, colocalized with activated smooth muscle cells and macrophages [7, 8]. Since plaque-derived PAPP-A is being considered as a new biomarker that may potentially play a role in the development of atherosclerotic lesions [9, 10]. A better
References
[1]
J. B. Lawrence, C. Oxvig, M. T. Overgaard et al., “The insulin-like growth factor (IGF)-dependent IGF binding protein-4 protease secreted by human fibroblasts is pregnancy-associated plasma protein-A,” Proceedings of the National Academy of Sciences of the United States of America, vol. 96, no. 6, pp. 3149–3153, 1999.
[2]
C. O. Ortiz, B. K. Chen, L. K. Bale, M. T. Overgaard, C. Oxvig, and C. A. Conover, “Transforming growth factor-β regulation of the insulin-like growth factor binding protein-4 protease system in cultured human osteoblasts,” Journal of Bone and Mineral Research, vol. 18, no. 6, pp. 1066–1072, 2003.
[3]
A. Bayes-Genis, R. S. Schwartz, D. A. Lewis et al., “Insulin-like growth factor binding protein-4 protease produced by smooth muscle cells increases in the coronary artery after angioplasty,” Arteriosclerosis, Thrombosis, and Vascular Biology, vol. 21, no. 3, pp. 335–341, 2001.
[4]
C. A. Conover, S. C. Harrington, and L. K. Bale, “Differential regulation of pregnancy associated plasma protein-A in human coronary artery endothelial cells and smooth muscle cells,” Growth Hormone & IGF Research, vol. 18, no. 3, pp. 213–220, 2008.
[5]
C. Heeschen, S. Dimmeler, C. W. Hamm, S. Fichtlscherer, M. L. Simoons, and A. M. Zeiher, “Pregnancy-associated plasma protein-A levels in patients with acute coronary syndromes: comparison with markers of systemic inflammation, platelet activation, and myocardial necrosis,” Journal of the American College of Cardiology, vol. 45, no. 2, pp. 229–237, 2005.
[6]
L. You, L. Li, F. Zhang, Q. Xu, and J. Ren, “A pilot study of the clinical relevance of the relationship between the serum level of pregnancy-associated plasma protein a and the degree of acute coronary syndrome,” The Journal of International Medical Research, vol. 38, no. 2, pp. 625–632, 2010.
[7]
A. Bayes-Genis, C. A. Conover, M. T. Overgaard et al., “Pregnancy-associated plasma protein A as a marker of acute coronary syndromes,” The New England Journal of Medicine, vol. 345, no. 14, pp. 1022–1029, 2001.
[8]
H. B. Boldt and C. A. Conover, “Pregnancy-associated plasma protein-A (PAPP-A): a local regulator of IGF bioavailability through cleavage of IGFBPs,” Growth Hormone & IGF Research, vol. 17, no. 1, pp. 10–18, 2007.
[9]
Z. T. Resch, C. Oxvig, L. K. Bale, and C. A. Conover, “Stress-activated signaling pathways mediate the stimulation of pregnancy-associated plasma protein-A expression in cultured human fibroblasts,” Endocrinology, vol. 147, no. 2, pp. 885–890, 2006.
[10]
S. C. Harrington, R. D. Simari, and C. A. Conover, “Genetic deletion of pregnancy-associated plasma protein-A is associated with resistance to atherosclerotic lesion development in apolipoprotein E-deficient mice challenged with a high-fat diet,” Circulation Research, vol. 100, no. 12, pp. 1696–1702, 2007.
[11]
Z. T. Resch, B. K. Chen, L. K. Bale, C. Oxvig, M. T. Overgaard, and C. A. Conover, “Pregnancy-associated plasma protein a gene expression as a target of inflammatory cytokines,” Endocrinology, vol. 145, no. 3, pp. 1124–1129, 2004.
[12]
N. Li and M. Karin, “Is NF-kappaB the sensor of oxidative stress?” The FASEB Journal, vol. 13, no. 10, pp. 1137–1143, 1999.
[13]
M. B. Lobbes, M. E. Kooi, E. Lutgens, et al., “Leukocyte counts, myeloperoxidase, and pregnancy-associated plasma protein a as biomarkers for cardiovascular disease: towards a multi-biomarker approach,” International Journal of Vascular Medicine, vol. 2010, Article ID 726207, 2010.
[14]
K. K. Iversen, B. Teisner, P. Winkel et al., “Pregnancy associated plasma protein-A as a marker for myocardial infarction and death in patients with stable coronary artery disease: a prognostic study within the CLARICOR Trial,” Atherosclerosis, vol. 214, no. 1, pp. 203–208, 2011.
[15]
G. Biasillo, M. Leo, R. della Bona, and L. M. Biasucci, “Inflammatory biomarkers and coronary heart disease: from bench to bedside and back,” Internal and Emergency Medicine, vol. 5, no. 3, pp. 225–233, 2010.
[16]
J. Lund, Q. P. Qin, T. Ilva et al., “Circulating pregnancy-associated plasma protein a predicts outcome in patients with acute coronary syndrome but no troponin I elevation,” Circulation, vol. 108, no. 16, pp. 1924–1926, 2003.
[17]
W. Y. Mei, Z. M. Du, Q. Zhao et al., “Pregnancy-associated plasma protein predicts outcomes of percutaneous coronary intervention in patients with non-ST-elevation acute coronary syndrome,” Heart & Lung: Journal of Acute and Critical Care, vol. 40, no. 3, pp. e78–e83, 2011.
[18]
J. Lund, S. Wittfooth, Q. P. Qin et al., “Free versus total pregnancy-associated plasma protein A (PAPP-A) as a predictor of 1-year outcome in patients presenting with non-ST-elevation acute coronary syndrome,” Clinical Chemistry, vol. 56, no. 7, pp. 1158–1165, 2010.
[19]
J. Cosin-Sales, J. C. Kaski, M. Christiansen et al., “Relationship among pregnancy associated plasma protein-A levels, clinical characteristics, and coronary artery disease extent in patients with chronic stable angina pectoris,” European Heart Journal, vol. 26, no. 20, pp. 2093–2098, 2005.
[20]
J. Cosin-Sales, M. Christiansen, P. Kaminski et al., “Pregnancy-associated plasma protein A and its endogenous inhibitor, the proform of eosinophil major basic protein (proMBP), are related to complex stenosis morphology in patients with stable angina pectoris,” Circulation, vol. 109, no. 14, pp. 1724–1728, 2004.
[21]
M. Rossen, K. Iversen, A. Teisner, B. Teisner, A. Kliem, and G. Grudzinskas, “Optimisation of sandwich ELISA based on monoclonal antibodies for the specific measurement of pregnancy-associated plasma protein (PAPP-A) in acute coronary syndrome,” Clinical Biochemistry, vol. 40, no. 7, pp. 478–484, 2007.
[22]
C. A. Conover, B. K. Chen, and Z. T. Resch, “Regulation of pregnancy-associated plasma protein-A expression in cultured human osteoblasts,” Bone, vol. 34, no. 2, pp. 297–302, 2004.
[23]
J. G. Filep, “Perplexity of monocyte responses to C-reactive protein (CRP),” Thrombosis and Haemostasis, vol. 99, no. 3, pp. 461–462, 2008.
[24]
G. Sangiorgi, A. Mauriello, E. Bonanno et al., “Pregnancy-associated plasma protein-A is markedly expressed by monocyte-macrophage cells in vulnerable and ruptured carotid atherosclerotic plaques. A link between inflammation and cerebrovascular events,” Journal of the American College of Cardiology, vol. 47, no. 11, pp. 2201–2211, 2006.
[25]
C. A. Conover, S. C. Harrington, L. K. Bale, and C. Oxvig, “Surface association of pregnancy-associated plasma protein-A accounts for its colocalization with activated macrophages,” American Journal of Physiology, vol. 292, no. 2, pp. H994–H1000, 2007.
[26]
G. Renier, I. Clément, A. C. Desfaits, and A. Lambert, “Direct stimulatory effect of insulin-like growth factor-I on monocyte and macrophage tumor necrosis factor-α production,” Endocrinology, vol. 137, no. 11, pp. 4611–4618, 1996.
[27]
H. Hirai, R. Kanaya, M. Maeda, D. Qungfang, K. Ina, and T. Hayashi, “The role of insulin growth factor on atherosclerosis and endothelial function: the effect on hyperlipidemia and aging,” Life Sciences, vol. 88, no. 9-10, pp. 425–431, 2011.
[28]
T. Lawrence, D. W. Gilroy, P. R. Colville-Nash, and D. A. Willoughby, “Possible new role for NF-κB in the resolution of inflammation,” Nature Medicine, vol. 7, no. 12, pp. 1291–1297, 2001.
[29]
A. R. Brasier, “The nuclear factor-B-interleukin-6 signalling pathway mediating vascular inflammation,” Cardiovascular Research, vol. 86, no. 2, pp. 211–218, 2010.
[30]
K. Van Der Heiden, S. Cuhlmann, L. A. Luong, M. Zakkar, and P. C. Evans, “Role of nuclear factor κB in cardiovascular health and disease,” Clinical Science, vol. 118, no. 10, pp. 593–605, 2010.
[31]
M. E. Ritchie, “Nuclear factor-κb is selectively and markedly activated in humans with unstable angina pectoris,” Circulation, vol. 98, no. 17, pp. 1707–1713, 1998.
[32]
Y. Ahn, Y. S. Kim, and M. H. Jeong, “The role of nuclear factor kappa B activation in atherosclerosis and ischemic cardiac injury,” Korean Circulation Journal, vol. 36, no. 4, pp. 245–251, 2006.
[33]
R. J. Bisoendial, S. M. Boekholdt, M. Vergeer, E. S. G. Stroes, and J. J. P. Kastelein, “C-reactive protein is a mediator of cardiovascular disease,” European Heart Journal, vol. 31, no. 17, pp. 2087–2095, 2010.
[34]
S. Devaraj, J. M. Yun, G. Adamson, J. Galvez, and I. Jialal, “C-reactive protein impairs the endothelial glycocalyx resulting in endothelial dysfunction,” Cardiovascular Research, vol. 84, no. 3, pp. 479–484, 2009.
