Role of PAPP-A in atherothrombosis: messages to take home

Long non-coding RNA MIAT/miR-148b/PAPPA axis modifies cell proliferation and migration in ox-LDL-induced human aorta vascular smooth muscle cells

AIMS

Atherosclerosis (AS) performs the important pathogenesis which refers to coronaryheart and vascular diseases. Long non-coding RNAs (lncRNAs) was reported to be related to the AS progression. We aimed to probe the role and potential mechanism of Myocardial Infarction Associated Transcript (MIAT) in AS.

MATERIALS AND METHODS

Levels of MIAT, microRNA-148b (miR-148b) and pregnancy-associated plasma protein A (PAPPA) were detected by quantitative Real-time polymerase chain reaction (qRT-PCR) in oxidized low-density lipoprotein (ox-LDL)-induced human aorta vascular smooth muscle cells (HA-VSMCs). Proliferation and migration were examined by Cell counting kit-8 (CCK-8) and wound-healing assays, respectively. Protein levels of Ki-67, proliferating cell nuclear antigen (PCNA), matrix metalloproteinase (MMP)-2, MMP-9 and PAPPA were examined by western blot assay. Ki-67 and PCNA level was detected by flow cytometry. The interaction among MIAT, miR-148b and PAPPA was confirmed via dual-luciferase reporter and RNA immunoprecipitation (RIP). The biology role of MIAT was detected by an AS model in vivo.

KEY FINDINGS

The levels of MIAT and PAPPA were augmented, whereas mature miR-148b level was repressed in ox-LDL-induced AS model. The inhibitory effects of knockdown of MIAT on proliferation and migration were relieved by miR-148b inhibitor. Additionally, miR-148b regulated proliferation and migration by targeting PAPPA. Mechanically, MIAT functioned as sponge of miR-148b to impact PAPPA expression. MIAT knockdown protected AS mice against lipid metabolic disorders in vivo.

SIGNIFICANCE

Proliferation and migration were modified by MIAT/miR-148b/PAPPA axis in ox-LDL induced AS cell model, supplying a novel insight into the underlying application of MIAT in the clinical treatment of AS.

Retracted Article: Knockdown of long non-coding RNA OIP5-AS1 suppresses cell proliferation and migration in ox-LDL-induced human vascular smooth muscle cells (hVMSCs) through targeting miR-152-3p/PAPPA axis

Emerging evidence has demonstrated that long non-coding RNA Opa-interacting protein 5 antisense RNA 1 (OIP5-AS1) is associated with cellular behaviors among malignant tumors. However, the role of OIP5-AS1 in atherosclerosis remains largely undefined. The aim of this study was to explore the expression and role of OIP5-AS1 in a cell model of atherosclerosis, as well as the underlying mechanism. We found that expression of OIP5-AS1 was upregulated in human vascular smooth muscle cells (hVMSCs) under oxidized low density lipoprotein (ox-LDL) administration, and knockdown of OIP5-AS1 suppressed cell viability (CCK-8) and proliferating cell nuclear antigen (PCNA) protein level in ox-LDL-treated hVMSCs, as well as inhibited cell migration rate (wound healing assay) and protein expression of matrix metalloproteinase (MMP)-2 and MMP-9. Mechanically, OIP5-AS1 functioned as competing endogenous RNA (ceRNA) to positively regulate PAPPA expression through sponging miRNA-152-3p (miR-152), and pregnancy-associated plasma protein A (PAPPA) was identified as a downstream target gene for miR-152. Moreover, expression of miR-152 was downregulated and PAPPA was upregulated in ox-LDL-treated hVMSCs. Similarly to OIP5-AS1 knockdown, miR-215 overexpression could inhibit cell proliferation and migration of hVMSCs administrated by ox-LDL, which was abated by PAPPA upregulation. Moreover, miR-215 downregulation partially reversed the suppressive role of OIP5-AS1 knockdown as well. In conclusion, knockdown of OIP5-AS1 suppressed ox-LDL-treated hVMSC proliferation and migration presumably through targeting miR-152/PAPPA axis, suggesting a novel OIP5-AS1/miR-152/PAPPA pathway in atherogenesis.

Pregnancy-associated plasma protein-A promotes TF procoagulant activity in human endothelial cells by Akt-NF-κB axis

Pregnancy-associated plasma protein-A (PAPP-A) is a metalloproteinase with a controversial role in pathophysiology of cardiovascular disease. It seems involved in progression of atherosclerosis and is widely represented in atherosclerotic plaque. PAPP-A plasma levels are elevated in patients with acute coronary syndromes (ACS), thus it has been suggested that it might be a prognostic marker for developing major cardiovascular events. However, the pathophysiological link(s) between PAPP-A and ACS are still unknown. Several studies have indicated that tissue factor (TF) plays a pivotal role in the pathophysiology of ACS by triggering the formation of intracoronary thrombi following endothelial injury. This study investigates whether PAPP-A, at concentrations measurable in ACS patients, might induce TF expression in human endothelial cells in culture (HUVEC). In HUVEC, PAPP-A induced TF-mRNA transcription as demonstrated by real time PCR and expression of functionally active TF as demonstrated by FACS analysis and pro-coagulant activity assay. PAPP-A induced TF expression through the activation of Akt/NF-κB axis, as demonstrated by luciferase assay and by suppression of TF-mRNA transcription as well as of TF expression/activity by Akt and NF-κB inhibitors. These data indicate that PAPP-A promotes TF expression in human endothelial cells and support the hypothesis that this proteinase, besides being involved in progression of atherosclerosis, does not represent an independent risk factor for adverse cardiovascular events, but it rather might play an "active" role in the pathophysiology of ACS as an effector molecule able to induce a pro-thrombotic phenotype in endothelial cells.

Examination of serum pregnancy-associated plasma protein A clinical value in acute coronary syndrome prediction and monitoring

INTRODUCTION

Chronic vascular inflammatory process promotes and intensifies all atherogenic events. The aim of this research was to estimate the clinical value of pregnancy-associated plasma protein A (PAPP-A) measurement associated with plaque destabilization and rupture in prediction and monitoring of acute coronary syndromes (ACS) as well as to assess the predictive value of this biomarker in comparison to traditional myocardial infarction (MI) risk markers.

MATERIAL AND METHODS

The study included 119 patients in 2 investigated groups and one control group. PAPP-A assay was performed using manual ELISA kit, DRG. All other parameters were determined using automatic analyzers: Olympus and Dade Behring.

RESULTS

A statistically significant difference between PAPP-A concentration median value was found in the investigated group MI individuals' serum and control group individuals' serum (11.42 ng/ml and 7.22 ng/ml respectively, p = 0.003). PAPP-A assay had the highest specificity (83.3%) and sensitivity (53.8%), and therefore the highest clinical value. In patients with clinically and laboratory confirmed MI we proved that PAPP-A serum level is a clinically useful biomarker in ACS prediction, better than C-reactive protein (hsCRP) and fibrinogen (FBG) level.

CONCLUSIONS

The highest diagnostic efficiency for ACS prediction was proved for simultaneous panel assays consisting of 2-3 parameters (PAPP-A - hsCRP, PAPP-A - FBG, PAPP-A - hsCRP - FBG), while PAPP-A itself does not show characteristics necessary for it to be used as a biomarker for MI dynamic monitoring. It is possible that prothrombotic component is mainly responsible for repeated major adverse cardiac events, more than inflammatory process.

Key questions and answers about pregnancy-associated plasma protein-A

Twenty-five years after it was identified as a circulating protein of unknown function derived from the placenta, pregnancy-associated plasma protein-A (PAPP-A) was discovered to be a novel zinc metalloproteinase expressed by a variety of cell types. Great progress has been made in understanding the biology of PAPP-A and its regulation during recent years, especially in regard to physiological and pathophysiological inflammatory injury responses. However, much remains to be learned about this complex protein and its potential clinical implications outside pregnancy. In this article we address some of the outstanding questions about PAPP-A, in particular about its newly emerging role in the insulin-like growth factor (IGF) system.