Role of GATA motifs in tissue factor pathway inhibitor gene expression in malignant cells

DNA Methylation as a Potential Molecular Mechanism in X-linked Dystonia-Parkinsonism

BACKGROUND

X-linked dystonia-parkinsonism is a neurodegenerative movement disorder. The underlying molecular basis has still not been completely elucidated, but likely involves dysregulation of TAF1 expression. In X-linked dystonia-parkinsonism, 3 disease-specific single-nucleotide changes (DSCs) introduce (DSC12) or abolish (DSC2 and DSC3) CpG dinucleotides and consequently sites of putative DNA methylation. Because transcriptional regulation tightly correlates with specific epigenetic marks, we investigated the role of DNA methylation in the pathogenesis of X-linked dystonia-parkinsonism.

METHODS

DNA methylation at DSC12, DSC3, and DSC2 was quantified by bisulfite pyrosequencing in DNA from peripheral blood leukocytes, fibroblasts, induced pluripotent stem cell-derived cortical neurons and brain tissue from X-linked dystonia-parkinsonism patients and age- and sex-matched healthy Filipino controls in a prospective study.

RESULTS

Compared with controls, X-linked dystonia-parkinsonism patients showed striking differences in DNA methylation at the 3 investigated CpG sites. Using methylation-sensitive luciferase reporter gene assays and immunoprecipitation, we demonstrated (1) that lack of DNA methylation because of DSC2 and DSC3 affects gene promoter activity and (2) that methylation at all 3 investigated CpG sites alters DNA-protein interaction. Interestingly, DSC3 decreased promoter activity per se compared with wild type, and promoter activity further decreased when methylation was present. Moreover, we identified specific binding of proteins to the investigated DSCs that are associated with splicing and RNA and DNA binding.

CONCLUSIONS

We identified altered DNA methylation in X-linked dystonia-parkinsonism patients as a possible additional mechanism modulating TAF1 expression and putative novel targets for future therapies using DNA methylation-modifying agents. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Emerging anticoagulant and thrombolytic drugs

Since its discovery, heparin has been used intensely as an anticoagulant for several medical and surgical indications. However, efforts are in progress to replace heparin because of its serious complications, such as intraoperative and postoperative bleeding, osteoporosis, alopecia, heparin resistance, heparin rebound, heparin-induced thrombocytopenia (HIT) and thrombosis syndrome (HITTS), and other disadvantages. Significant developments in the field of new anticoagulants have resulted in the evaluation and introduction of low molecular weight heparins (LMWHs) and heparinoids, hirudin, ancrod, synthetic peptides and peptidomimetics. However, despite significant progress in the development of these new anticoagulants, a better or an ideal anticoagulant for cardiovascular patients is not yet available and heparin still continues to amaze both basic scientists and the clinicians. To minimise the adverse effects of heparin, newer approaches to optimise its use in combination with the new anticoagulants may provide better clinical outcome. In our experience, the off-label use of argatroban at a dose of 300 microg/kg iv. bolus followed by 10 microg/kg/minute infusion in combination with aggrastat (a glycoprotein [GP] IIb/IIIa inhibitor) at a dose of 10 microg/kg iv. bolus followed by an infusion of 0.15 microg/kg/minute in patients with HIT undergoing percutaneous coronary interventions resulted in elevation of celite activated clotting time (ACT) to 300 seconds followed by a gradual decline and the ACT remained above 200 seconds even after 200 min of drug administration. A bewildering array of newer anticoagulants now exist, such as LMWHs and heparinoids, indirect or direct thrombin inhibitors, oral thrombin inhibitors, such as melagatran (AstraZeneca) and HC-977 (Mitsubishi Pharmaceuticals), Factor IXa inhibitors, indirect or direct Factor Xa inhibitors, Factor VIIa/tissue factor (TF) pathway inhibitor, newer antiplatelet agents, such as GPIIb/IIIa inhibitors, fibrin specific thrombolytic agent, such as tenecteplase and modulation of the endogenous fibrinolytic activity by thrombin activatable fibrinolytic inhibitor (TAFI), Factor XIIIa inhibitors and PAI-1 inhibitors. The quest for newer anticoagulant, antiplatelet and fibrinolytic agents will continue until ideal agents are found.

Regulation of functions of vascular wall cells by tissue factor pathway inhibitor: basic and clinical aspects

Tissue factor pathway inhibitor (TFPI) is a Kunitz-type protease inhibitor that inhibits the initial reactions of blood coagulation. A major pool of TFPI is the form associated with the surface of endothelial cells, which is speculated to play an important role in regulating the functions of vascular wall cells. TFPI consists of 3 tandem Kunitz inhibitor domains, the first and second of which inhibit the tissue factor-factor VIIa complex and factor Xa, respectively. Recent findings indicate that TFPI has another function, ie, the modulation of cell proliferation. This function is based on the interaction of the C-terminal region of TFPI with these cells. In addition to endothelial cells, it has been shown that many other vascular wall cells can synthesize TFPI, eg, mesangial cells, smooth muscle cells, monocytes, fibroblasts, and cardiomyocytes. TFPI is associated with these cells mainly through heparan sulfate proteoglycans on their surface. However, recent findings suggest that there are several other candidates for TFPI-binding proteins on these cells. On the other hand, studies on plasma levels of TFPI in patients with various diseases suggest that TFPI may be a marker of endothelial cell dysfunction. An increasing number of reports suggest that recombinant TFPI may attenuate thrombosis and prevent restenosis. Clinical trials are needed to explore these possibilities. Recent reports also indicate that the application of recombinant TFPI or TFPI gene transfer prevents restenosis in addition to thrombosis after arterial injury in the animal model; corroboration of these reports awaits clinical investigation.