A rare coding mutation in the MAST2 gene causes venous thrombosis in a French family with unexplained thrombophilia: The Breizh MAST2 Arg89Gln variant.

Rare variants outside the classical coagulation cascade might cause inherited thrombosis. We aimed to identify the variant(s) causing venous thromboembolism (VTE) in a family with multiple relatives affected with unprovoked VTE and no thrombophilia defects. We identified by whole exome sequencing an extremely rare Arg to Gln variant (Arg89Gln) in the Microtubule Associated Serine/Threonine Kinase 2 (MAST2) gene that segregates with VTE in the family. Free-tissue factor pathway inhibitor (f-TFPI) plasma levels were significantly decreased in affected family members compared to healthy relatives. Conversely, plasminogen activator inhibitor-1 (PAI-1) levels were significantly higher in affected members than in healthy relatives. RNA sequencing analysis of RNA interference experimental data conducted in endothelial cells revealed that, of the 13,387 detected expressed genes, 2,354 have their level of expression modified by MAST2 knockdown, including SERPINE1 coding for PAI-1 and TFPI. In HEK293 cells overexpressing the MAST2 Gln89 variant, TFPI and SERPINE1 promoter activities were respectively lower and higher than in cells overexpressing the MAST2 wild type. This study identifies a novel thrombophilia-causing Arg89Gln variant in the MAST2 gene that is here proposed as a new molecular player in the etiology of VTE by interfering with hemostatic balance of endothelial cells.

Whole-Blood miRNA Sequencing Profiling for Vasospasm in Patients With Aneurysmal Subarachnoid Hemorrhage.

Background and Purpose- Arterial vasospasm is a well-known delayed complication of aneurysmal subarachnoid hemorrhage (aSAH). However, no validated biomarker exists to help clinicians discriminating patients with aSAH who will develop vasospasm (VSP+) and identifying those who then deserve aggressive preventive therapy. We hypothesized that whole-blood miRNAs could be a source of candidate biomarkers for vasospasm. Methods- Using a next-generation sequencing approach, we performed whole-blood miRNA profiling between VSP+patients with aSAH and patients who did not develop vasospasm (VSP-) in a prospective cohort of 32 patients. Profiling was performed on the admission day and 3 days before vasospasm. Results- Four hundred forty-two miRNAs were highly expressed in whole blood of patients with aSAH. Among them, hsa-miR-3177-3p demonstrated significant ( P=5.9×10-5; PBonferronicorrected=0.03) lower levels in VSP- compared with VSP+ patients. Looking for whole-blood mRNA correlates of hsa-miR-3177-3p, we observed some evidence that the decrease in hsa-miR-3177-3p levels after aSAH was associated with an increase in LDHA mRNA levels in VSP- ( P<10-3) but not in VSP+ ( P=0.66) patients. Conclusions- Whole-blood miRNA levels of hsa-miR-3177-3p could serve as a biomarker for vasospasm. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT01779713.

Whole blood levels of S1PR4 mRNA associated with cerebral vasospasm after aneurysmal subarachnoid hemorrhage.

OBJECTIVE: The authors sought to identify mRNA biomarkers of cerebral vasospasm in whole blood of patients suffering from aneurysmal subarachnoid hemorrhage (aSAH). METHODS: A prospective transcriptomic study for vasospasm was conducted in whole blood samples of 44 aSAH patients who developed (VSP+ group, n = 22) or did not develop (VSP- group, n = 22) vasospasm. Samples from all patients were profiled for 21,460 mRNA probes using the Illumina Human HT12v4.0 array. Differential statistical analysis was performed using a linear mixed model. RESULTS: Levels of sphingosine-1-phosphate receptor 4 (S1PR4) mRNA were significantly higher (p = 8.03 × 10-6) at presentation in patients who developed vasospasm after aSAH than in patients who did not. CONCLUSIONS: The results, which are consistent with findings of previous experimental investigations conducted in animal models, support the role of S1PR4 and its ligand, sphingosine-1-phosphate (S1P), in arterial-associated vasoconstriction, which suggests that S1PR4 could be used as a biomarker for cerebral vasospasm in aSAH patients.

A Genome Wide Association Study on plasma FV levels identified PLXDC2 as a new modifier of the coagulation process.

BACKGROUND: Factor V (FV) is a circulating protein primarily synthesized in the liver, and mainly present in plasma. It is a major component of the coagulation process. OBJECTIVE: To detect novel genetic loci participating to the regulation of FV plasma levels. METHODS: We conducted the first Genome Wide Association Study on FV plasma levels in a sample of 510 individuals and replicated the main findings in an independent sample of 1156 individuals. RESULTS: In addition to genetic variations at the F5 locus, we identified novel associations at the PLXDC2 locus, with the lead PLXDC2 rs927826 polymorphism explaining ~3.7% (P = 7.5 × 10-15 in the combined discovery and replication samples) of the variability of FV plasma levels. In silico transcriptomic analyses in various cell types confirmed that PLXDC2 expression is positively correlated to F5 expression. SiRNA experiments in human hepatocellular carcinoma cell line confirmed the role of PLXDC2 in modulating factor F5 gene expression, and revealed further influences on F2 and F10 expressions. CONCLUSION: Our study identified PLXDC2 as a new molecular player of the coagulation process.