LIM-only protein FHL2 attenuates vascular tissue factor activity, inhibits thrombus formation in mice and FHL2 genetic variation associates with human venous thrombosis

Apolipoprotein L Domain Containing 1 Inhibits Tissue Factor to Impede Thrombus Formation in a Rat Model of Deep Vein Thrombosis via Activating PI3K/Akt Pathway

BACKGROUND

Deep venous thrombosis (DVT) is one of the major health problems worldwide. Apolipoprotein L domain containing 1 (APOLD1) was reported to be downregulated in DVT. The present study intended to investigate whether APOLD1 affects thrombus formation in a rat model of DVT.

METHODS

The rat model of DVT was established by inferior vena cava (IVC) stenosis. At 6 hr, 12 hr, 24 hr, and 48 hr after IVC stenosis, the gross IVC with thrombus was dissected and observed. Then, the rats were preinjected with the lentiviral overexpression vector, APOLD1-LVs, 1 hr before IVC stenosis, to evaluate the influence of APOLD1 on thrombosis in rats. The serum levels of D-dimer and TAT as well as the content of TF in IVC tissues were detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS

IVC stenosis resulted in thrombus formation in rats, increased serum levels of D-dimer and TAT, and decreased APOLD1 expression. APOLD1 overexpression inhibited in vivo thrombosis, reduced serum levels of D-dimer, and downregulated tissue factor (TF) activity and level. APOLD1 overexpression also increased p-PI3K and p-Akt protein levels.

CONCLUSIONS

APOLD1 suppresses thrombus formation in a rat model of DVT via downregulating TF expression by activating the PI3K/Akt pathway.

Metformin inhibits multiple myeloma serum-induced endothelial cell thrombosis by down-regulating miR-532

OBJECTIVES

Thrombotic complications in multiple myeloma (MM) impairs the quality of life of patients. Metformin has a certain effect on anti-thrombosis, but its role and mechanism in MM-induced thrombosis are still uncovered. Therefore, this study evaluated the effect of metformin on MM-induced thrombosis.

METHODS

Human umbilical vein endothelial cells (HUVECs) were exposed to normal serum (15%), MM serum (15%), metformin (0.01 mmol/L), or MM serum and metformin simultaneously. The expression of tissue factor (TF) in HUVECs was detected by flow cytometry and quantitative real-time PCR (qRT-PCR). QRT-PCR was also used to determine the expressions of endothelial protein C receptor (EPCR) and miR-532. The generation of thrombin and activated protein C was measured by thrombin generation and protein C activation assays. And EPCR, extracellular signal-regulated kinase (ERK) 1/2, p38 mitogen activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) pathway related protein expressions were detected by western blot.

RESULT

MM serum increased the expressions of TF, EPCR and miR-532, and induced thrombin generation and protein C activation in HUVECs. Based on the MM serum treatment, metformin decreased these expressions and inhibited the thrombin generation and protein C activation in HUVECs. However, miR-532 mimic reversed the effect of metformin and promoted the levels of thrombosis related indicators in HUVECs. Moreover, metformin activated the EPCR, ERK 1/2, p38 MAPK and NF-κB pathways but miR-532 mimic suppressed the activation of pathways.

CONCLUSION

Metformin played an inhibitory effect on MM serum-induced HUVEC thrombosis, suggesting that metformin could serve as a novel antithrombotic approach for MM patients.

How (Epi)Genetic Regulation of the LIM-Domain Protein FHL2 Impacts Multifactorial Disease

Susceptibility to complex pathological conditions such as obesity, type 2 diabetes and cardiovascular disease is highly variable among individuals and arises from specific changes in gene expression in combination with external factors. The regulation of gene expression is determined by genetic variation (SNPs) and epigenetic marks that are influenced by environmental factors. Aging is a major risk factor for many multifactorial diseases and is increasingly associated with changes in DNA methylation, leading to differences in gene expression. Four and a half LIM domains 2 (FHL2) is a key regulator of intracellular signal transduction pathways and the FHL2 gene is consistently found as one of the top hyper-methylated genes upon aging. Remarkably, FHL2 expression increases with methylation. This was demonstrated in relevant metabolic tissues: white adipose tissue, pancreatic β-cells, and skeletal muscle. In this review, we provide an overview of the current knowledge on regulation of FHL2 by genetic variation and epigenetic DNA modification, and the potential consequences for age-related complex multifactorial diseases.

Endothelial Dysfunction in Pulmonary Hypertension: Cause or Consequence?

Pulmonary arterial hypertension (PAH) is a rare, complex, and progressive disease that is characterized by the abnormal remodeling of the pulmonary arteries that leads to right ventricular failure and death. Although our understanding of the causes for abnormal vascular remodeling in PAH is limited, accumulating evidence indicates that endothelial cell (EC) dysfunction is one of the first triggers initiating this process. EC dysfunction leads to the activation of several cellular signalling pathways in the endothelium, resulting in the uncontrolled proliferation of ECs, pulmonary artery smooth muscle cells, and fibroblasts, and eventually leads to vascular remodelling and the occlusion of the pulmonary blood vessels. Other factors that are related to EC dysfunction in PAH are an increase in endothelial to mesenchymal transition, inflammation, apoptosis, and thrombus formation. In this review, we outline the latest advances on the role of EC dysfunction in PAH and other forms of pulmonary hypertension. We also elaborate on the molecular signals that orchestrate EC dysfunction in PAH. Understanding the role and mechanisms of EC dysfunction will unravel the therapeutic potential of targeting this process in PAH.