Lysophosphatidic Acid Is Associated with Atherosclerotic Plaque Instability by Regulating NF-κB Dependent Matrix Metalloproteinase-9 Expression via LPA2 in Macrophages

Abstract

Lysophosphatidic acid (LPA), one of the simplest phospholipid signaling molecules, participates in formation and disruption of atherosclerotic plaque. Matrix metalloproteinases (MMPs) contribute to atherosclerotic plaque rupture by involving in extracellular matrix (ECM) degradation and then thinning fibrous cap. Our previous study demonstrated that macrophage-derived MMP-9 was associated with coronary plaque instability, but the relationship between LPA and MMP-9 remains unclear. The present work therefore aimed at elucidating association between LPA and MMP-9 and the regulation mechanism of LPA on MMP-9 in macrophages. We found that plasma LPA and MMP-9 levels were correlated positively (r = 0.31, P < 0.05) and both elevated significantly in patients with acute myocardial infarct (AMI). Consistent with peripheral blood levels, histochemical staining indicated that autotaxin (ATX), LPA-producing ectoenzyme, and MMP-9 were expressed frequently in the necrotic core and fibrous cap of human unstable plaques, which might increase the instability of plaque. Experiments in vitro were done with THP-1-derived macrophages and showed that LPA enhanced the expression, secretion and activity of MMP-9 in a time- and dose-dependent manner. Induction of LPA on pro-MMP-9 and active-MMP-9 was confirmed in human peripheral blood monocyte-derived macrophages. PDTC, NF-κB inhibitor, but not inhibitor of AP-1 and PPARγ, effectively prevented LPA-induced MMP-9 expression and NF-κB p65 siRNA decreased MMP-9 transcription, confirming that LPA might induce MMP-9 elevation by activating NF-κB pathway. In addition, knockdown of LPA2 attenuated LPA-induced MMP-9 expression and nucleus p65 levels. These findings revealed that LPA upregulated the expression of MMP-9 through activating NF-κB pathway in the LPA2 dependent manner, hence blocking LPA receptors signaling may provide therapeutic strategy to target plaque destabilization.

Matrix Metalloproteinases as Biomarkers of Atherosclerotic Plaque Instability

“…This is particularly important due to the fact that MMP-9 is derived from macrophages with coronary plaque instability. As demonstrated by Gu et al, LPA acting through the LPA2 receptor can induce MMP-9 by activating the NF-κB pathway [129] (Table 2).…”

Lysophosphatidic Acid Is Associated With Cardiac Dysfunction and Hypertrophy by Suppressing Autophagy via the LPA3/AKT/mTOR Pathway

“…LPA, as a phospholipid signaling molecule, which is produced from circulating lysophosphatidylcholine (LPC) by ATX, is involved in multiple cardiovascular diseases ( Smyth et al, 2014 ; Chen et al, 2017 ; Gu et al, 2017 ; Nsaibia et al, 2017 ; Shen et al, 2018 ). It has been reported that LPA is present in abundance in the serum of patients with an acute myocardial infarction (AMI) ( Chen et al, 2003 ), and LPA1 and LPA3 receptor protein levels are increased in the ischemic heart that develops cardiac remodeling, implying that LPA plays a role in cardiac remodeling after a MI.…”

Lysophosphatidic acid induces the migration and invasion of SGC-7901 gastric cancer cells through the LPA2 and Notch signaling pathways

“…LPA2 is also involved in biological behaviors, including proliferation, anti-apoptosis, drug resistance, metastasis and the invasion of numerous cancer cells, resulting in poor clinic outcomes (10-13). Furthermore, LPA upregulates the expression of matrix metalloprotein-9 through activating the nuclear factor-κB pathway in a LPA2 dependent manner (14).…”