TAFI polymorphisms at amino acids 147 and 325 are not risk factors for cerebral infarction

Carboxypeptidase U (CPU, TAFIa, CPB2) in Thromboembolic Disease: What Do We Know Three Decades after Its Discovery?

Procarboxypeptidase U (proCPU, TAFI, proCPB2) is a basic carboxypeptidase zymogen that is converted by thrombin(-thrombomodulin) or plasmin into the active carboxypeptidase U (CPU, TAFIa, CPB2), a potent attenuator of fibrinolysis. As CPU forms a molecular link between coagulation and fibrinolysis, the development of CPU inhibitors as profibrinolytic agents constitutes an attractive new concept to improve endogenous fibrinolysis or to increase the efficacy of thrombolytic therapy in thromboembolic diseases. Furthermore, extensive research has been conducted on the in vivo role of CPU in (the acute phase of) thromboembolic disease, as well as on the hypothesis that high proCPU levels and the Thr/Ile325 polymorphism may cause a thrombotic predisposition. In this paper, an overview is given of the methods available for measuring proCPU, CPU, and inactivated CPU (CPUi), together with a summary of the clinical data generated so far, ranging from the current knowledge on proCPU concentrations and polymorphisms as potential thromboembolic risk factors to the positioning of different CPU forms (proCPU, CPU, and CPUi) as diagnostic markers for thromboembolic disease, and the potential benefit of pharmacological inhibition of the CPU pathway.

Genetic Polymorphisms Associated with Thrombotic Disease Comparison of Two Territories: Myocardial Infarction and Ischemic Stroke

Background and Purpose

The thrombin-activatable fibrinolysis inhibitor (TAFI) is an important inhibitor of fibrinolysis and plays a critical role in the pathogenesis of arterial thrombosis; genetic polymorphisms of the TAFI gene affect its activity and increase the risk of thrombosis. Moreover, studies in young patients are still scarce. The aim was to examine the contribution of the Thr325Ile and Ala147Thr polymorphisms with ST acute myocardial infarction (STEMI) or idiopathic ischemic stroke (IIS) in the young Mexican population.

Methods

A total of 244 patients with STEMI ≤45 years of age and 244 controls. In a second study, 250 patients with IIS ≤45 years of age were recruited, including 250 controls. In both studies, cases and controls were matched by age and sex. The polymorphisms were determined in all participants by PCR-RFLP.

Results

There was significant difference in the Thr325Ile genotype distribution (P = 0.001) and allele frequency (P = 0.001) between STEMI and control groups, but no difference in the Ala147Thr genotype distribution (P = 0.24) and allele frequency (P = 0.46), neither in the Thr325Ile genotype distribution (P = 0.25) nor in the Ala147Thr genotype distribution (P = 0.46) or their allele frequencies; there was significant difference between IIS and the control group. There were independent factors for STEMI: the Ile allele (P = 0.01), type 2 diabetes mellitus (P = 0.001), hypertension (P = 0.001), smoking (P = 0.001), dyslipidemia (P = 0.001), and family history of atherothrombotic disease (P = 0.001). The independent factors for IIS were hypertension (P = 0.001), smoking (P < 0.01), and family history of atherothrombotic disease (P < 0.01).

Conclusions

The Thr325Ile polymorphism, but no Ala147Thr polymorphism, represents an independent risk factor for STEMI in the young Mexican population.

Thrombin-Activatable Fibrinolysis Inhibitor Polymorphisms and Cerebral Venous Thrombosis in Mexican Mestizo Patients

Thrombin-activatable fibrinolysis inhibitor (TAFI) gene polymorphisms have been proposed as a predisposing factor for cerebral venous thrombosis (CVT). We analyzed the association between CVT and TAFI single-nucleotide polymorphisms (rs3742264, rs2146881, and rs1926447) compared to healthy controls. Mexico Mestizo confirmed cases with CVT and age- and sex-matched controls with no history of venous thrombotic events were recruited from July 2006 to July 2015. Demographic, clinical, and imaging information was included in the analysis. Genotyping single-nucleotide polymorphisms were performed by allele-specific polymerase chain reaction. Allelic univariate analysis, haplotype association, and Hardy-Weinberg equilibrium were assessed. A total of 113 CVT cases (94 females [83.2%]; median age 35 years [interquartile range 27-43 years]) and 134 age- and sex-matched controls were included. The main risk factors for CVT were pregnancy/puerperium (30.9%), oral contraceptive use (19.5%), and hereditary thrombophilia (7.1%). We found no significant association for heterozygous and homozygous models for rs3742264 ( P = .30 and P = .69, respectively), rs2146881 ( P = .90 and P = .17, respectively), or rs1926447 ( P = .40 and P = .52, respectively) compared to controls; these findings were consistent in subgroup and haplotype analyses. In conclusion, TAFI rs3742264, rs2146881, and rs1926447 polymorphisms do not increase the risk of CVT in comparison to healthy controls.

Identification of genetic risk factors associated with ischaemic stroke in young Mexican patients

INTRODUCTION

Numerous polymorphisms in candidate genes coding for haemostatic system proteins have been proposed as risk factors for thrombosis.

METHODS

We performed a case-control study of consecutive ischaemic stroke survivors aged ≤ 45 years, treated at our neurology department from 2006 to 2014. Polymerase chain reaction-restriction fragment length polymorphism identified the following polymorphisms: Thr325Ile and Ala147Thr in TAFI, 4G/5G in PAI-1, PLA1/A2 in platelet glycoprotein IIb/IIIa, Glu298Asp in eNOS, and C677T in 5,10-MTHFR. A multivariate logistic regression analysis was performed to evaluate the independent risk of stroke.

RESULTS

204 cases and 204 age- and sex-matched controls were included in the study. Clinical and genetic variables associated with ischaemic stroke were hypertension (P=.03), tobacco use (P=.02), and the polymorphisms Glu298Asp (genotype: P=.001, allele frequency: P=.001) and C677T (genotype: P=.01); the Ala147Thr, Thr325IIe, 4G/5G, and PLA1/A2 mutations were not associated with ischaemic stroke. The 298Asp (P=.03) and T (P=.01) alleles, hypertension (P=.03), tobacco use (P=.01) and family history of stroke (P=.04) were identified as independent risk factors.

CONCLUSIONS

The polymorphisms Glu298Asp and C677T, affecting the eNOS and 5,10-MTHFR enzymes, respectively, and smoking, hypertension, and family history of stroke were associated with ischaemic stroke in young Mexican patients; this was not the case for the Thr325Ile, Ala147Thr, 4G/5G, and PLA1/A2 polymorphisms of the genes coding for fibrinolytic proteins and platelet receptors.

Aspirin ameliorates cerebral infarction through regulation of TLR4/NF‑κB‑mediated endoplasmic reticulum stress in mouse model

Cerebral infarction is a cerebrovascular disease caused by local brain ischemic necrosis or softening, which is associated with diabetes, obesity, hypertension and rheumatic heart arrhythmia. Previous studies have indicated that aspirin is a potential oral anticoagulant in the treatment of cerebral ischemic stroke. However, the potential mechanism mediated by aspirin in cerebral infarction therapy is not well understood. The present study analyzed the therapeutic effects of aspirin on cerebral infarction and investigated the underlying molecular mechanism of aspirin‑ameliorated benefits for thrombolysis. The results demonstrated that aspirin inhibited inflammation and apoptosis of cerebrovascular endothelial cells in a mouse model of cerebral infarction. Aspirin treatment suppressed toll‑like receptor (TLR)4 and nuclear factor (NF)‑κB expression in cerebrovascular endothelial cells. Endoplasmic reticulum (ER) stress was suppressed by aspirin treatment through the downregulation of protein kinase R‑like endoplasmic reticulum kinase, eukaryotic translation initiation factor 2 subunit 1 and C/EBP homologous protein expression levels in cerebrovascular endothelial cells. It was identified that knockdown of TLR4 inhibited aspirin‑mediated downregulation of NF‑κB signaling pathway and ER stress in cerebrovascular endothelial cells. Expression levels of adenosine diphosphate plasminogen activator inhibitors, von Willebrand factor and thromboxane were downregulated in cerebrovascular endothelial cells and in serum in experimental mice. The results demonstrated that aspirin was beneficial forthrombolysis by decreasing thrombin‑activatable fibrinolysis inhibitor and plasminogen activator inhibitor‑1 expression in a mouse model of cerebral infarction. These results suggested that aspirin may improve cerebral infarction by downregulating TLR4/NF‑κB‑mediated ER stress in a mouse model.

Genetic variations in the thrombin-activatable fibrinolysis inhibitor gene and risk of cardiovascular disease: a systematic review and meta-analysis

BACKGROUND

An imbalance between coagulation and fibrinolytic system plays an important role in the pathogenesis of arterial thrombosis. It has been identified that elevated plasma thrombin-activatable fibrinolysis inhibitor (TAFI) concentration, an anti-fibrinolytic factor, is associated with an increased risk of cardiovascular disease (CVD). But the effect of genetic variations in TAFI gene on the risk of CVD is inconclusive.

OBJECTIVES

To investigate the associations between two variants Ala147Thr(rs3742264) and Thr325Ile(rs1926447) in TAFI and the risk of CVD.

METHODS

Systematic review and meta-analysis of eligible studies published before January 2014. Coronary heart disease(CHD) and stroke are regarded as end-points of CVD.

RESULTS

A total of 18 articles including 23 studies were enrolled. Among these articles were 19 studies of Ala147Thr and 15 of Thr325Ile variants, comprising 4,977 CVD patients and 8,082 controls together with 4,890 cases and 8,311 controls, respectively. There were no significant associations between Ala147Thr variant and CVD under allele, dominant, recessive genetic models. Similar results were observed when end-point, ethnicity, sample size, genotyping method were taken into account. Likewise, meta-analysis of Thr325Ile variant did not show significant associations with CVD under three genetic models. Nevertheless, in sub-analysis based on end-point, the TT(Ile/Ile) genotype was associated with a 25% higher risk of coronary heart disease(CHD) (OR=1.25, 95%CI, 1.02-1.54; P=0.03) compared with TC+CC(Thr/Ile+Thr/Thr) genotype(recessive model).

CONCLUSIONS

The present meta-analysis failed to confirm the influence of Ala147Thr and Thr325Ile variants on the susceptibility to CVD. However, potentially increased risk of CHD was detected in Ile325 allele carriers under recessive model.

Association between polymorphisms in the flanking region of the TAFI gene and atherosclerotic cerebral infarction in a Chinese population

Background

Atherosclerosis is the leading etiologic factor of Atherosclerotic Cerebral Infarction (ACI). Previous studies have shown that thrombin activatable fibrinolysis inhibitor (TAFI) may play an important role in the occurrence of acute cerebral infarction, and the levels of TAFI are affected by several single nucleotide polymorphisms (SNPs) located in the regulatory and coding regions of the gene encoding TAFI. The present study aimed to determine whether polymorphisms (TAFI –2345 2G/1G, –1690 A/G, –438 A/G, +1583 A/T) of the TAFI gene were associated with ACI in a Han Chinese population.

Methods

The variant genotypes were identified by restriction fragment length polymorphism (RFLP) and allele-specific polymerase chain reactions (AS-PCR) in 225 patients with ACI and 184 age-matched healthy individuals.

Results

There was a significant difference in the genotype and allele frequencies of TAFI –2345 2G/1G and −1690 A/G polymorphisms between the ACI and control subjects. Further stratification analysis by gender revealed that the presence of the –438 AA genotype and the A allele conferred a higher risk of developing ACI in male patients (p < 0.05). Haplotype analysis demonstrated that four haplotypes of TAFI are significantly associated with ACI.

Conclusions

Our study provides preliminary evidence that the TAFI –2345 2G/1G and –1690 A/G polymorphisms are associated with ACI susceptibility in a Han Chinese population.

Plasma Levels of Unactivated Thrombin Activatable Fibrinolysis Inhibitor (TAFI) Are Down-Regulated in Young Adult Women: Analysis of a Normal Japanese Population

Thrombin-activatable fibrinolysis inhibitor (TAFI) is an anaphylatoxin-inactivating enzyme generated by proteolytic cleavage of its zymogen, and is the same enzyme as that first designated by our group as procarboxypeptidase R (proCPR). TAFI in plasma is presumed to influence vascular disease in its role as a fibrinolysis inhibitor. The activity of TAFI is strongly influenced by genetic polymorphism, especially at amino acids Thr/Ala-147 and Thr/Ile-325. In this study, we analyzed 202 healthy controls who were not on any medication, had no unusual medical history and whose blood data were normal. In a previous report, we established an enzyme-linked immunosorbent assay (ELISA) specific for non-activated TAFI (proCPR), and investigated levels of unactivated TAFI as an estimate of anti-fibrinolytic capacity. In this study, we determined normal Japanese TAFI levels for each age, sex, and genetic polymorphism of Thr/Ala-147 and Thr/Ile-325, and also showed that the TAFI level in young adult women is lower than in aged women.

Brain site-specific proteome changes in aging-related dementia

This study is aimed at gaining insights into the brain site-specific proteomic senescence signature while comparing physiologically aged brains with aging-related dementia brains (for example, Alzheimer's disease (AD)). Our study of proteomic differences within the hippocampus (Hp), parietal cortex (pCx) and cerebellum (Cb) could provide conceptual insights into the molecular mechanisms involved in aging-related neurodegeneration. Using an isobaric tag for relative and absolute quantitation (iTRAQ)-based two-dimensional liquid chromatography coupled with tandem mass spectrometry (2D-LC-MS/MS) brain site-specific proteomic strategy, we identified 950 proteins in the Hp, pCx and Cb of AD brains. Of these proteins, 31 were significantly altered. Most of the differentially regulated proteins are involved in molecular transport, nervous system development, synaptic plasticity and apoptosis. Particularly, proteins such as Gelsolin (GSN), Tenascin-R (TNR) and AHNAK could potentially act as novel biomarkers of aging-related neurodegeneration. Importantly, our Ingenuity Pathway Analysis (IPA)-based network analysis further revealed ubiquitin C (UBC) as a pivotal protein to interact with diverse AD-associated pathophysiological molecular factors and suggests the reduced ubiquitin proteasome degradation system (UPS) as one of the causative factors of AD.

TAFI gene polymorphisms in patients with cerebral venous thrombosis

Gene polymorphisms of thrombin activatable fibrinolysis inhibition (TAFI) factor have been investigated in various studies in terms of etiology (recurrence) and treatment (fibrinolytic effect) of thrombus formation. Cerebral venous thrombosis (CVT) is a life-threatening disease observed in young persons. Fifty-nine patients with CVT and 100 healthy control subjects were enrolled in the case/control study. The association between TAFI gene polymorphisms -438G>A, +505A>G and +1040C>T and cerebral venous thrombosis was investigated. It was found that frequencies of polymorphic genotype and allele were not different in patients than in control group and that they were not significant for cerebral venous thrombosis.

Characterization of the novel protein P9TLDR (temporal lobe down-regulated) with a brain-site-specific gene expression modality in Alzheimer's disease brain

Alzheimer's disease (AD) is an aging-related neurodegenerative disorder characterized by irreversible loss of higher cognitive functions. The disease is characterized by the presence of amyloid plaques and neurofibrillary tangles (NFT). In the current study we isolated from an intra-cerebral brain-site-specific (AD temporal lobe vs. AD occipital lobe) polymerase chain reaction (PCR)-select cDNA suppression subtractive hybridization (PCR-cDNA-SSH) expression analysis the novel gene P9TLDR, potentially a microtubule-associated protein involved in neuronal migration, with an altered expression pattern: down-regulated in the temporal lobe cortex of early stage AD brains. In an in vitro AD-related cell model, amyloid-β peptide (Aβ)-treated neurons, reduced P9TLDR expression correlated with increased tau protein phosphorylation. In conclusion, interference with the P9TLDR signalling pathways might be a therapeutic strategy for the treatment of AD.

The novel protein MANI modulates neurogenesis and neurite-cone growth

Neuronal regeneration and axonal re-growth in the injured mammalian central nervous system remains an unsolved field. To date, three myelin-associated proteins [Nogo or reticulon 4 (RTN4), myelin-associated glycoprotein (MAG) and oligodendrocyte myelin glycoprotein (OMG)] are known to inhibit axonal regeneration via activation of the neuronal glycosylphosphatidylinositol-anchored Nogo receptor [NgR, together with p75 neurotrophin receptor (p75NTR) and Lingo-1]. In the present study we describe the novel protein MANI (myelin-associated neurite-outgrowth inhibitor) that localizes to neural membranes. Functional characterization of MANI overexpressing neural stem cells (NSCs) revealed that the protein promotes differentiation into catecholaminergic neurons. Yeast two-hybrid screening and co-immunoprecipitation experiments confirmed the cell division cycle protein 27 (Cdc27) as an interacting partner of Mani. The analyses of Mani-overexpressing PC12 cells demonstrated that Mani retards neuronal axonal growth as a positive effector of Cdc27 expression and activity. We show that knockdown of Cdc27, a component of the anaphase-promoting complex (APC), leads to enhanced neurite outgrowth. Our finding describes the novel MANI-Cdc27-APC pathway as an important cascade that prevents neurons from extending axons, thus providing implications for the potential treatment of neurodegenerative diseases.

Genetics of coagulation: considerations for cardiac surgery

Genetic variants in the coagulation system have been known since antiquity. Today, because of modern improvements in diagnosis and medical management, the clinician is likely to encounter a spectrum of coagulation factor deficiencies and identified polymorphic variants in the surgical population. Because perioperative hemorrhagic and thrombotic complications are potentially serious, it is important to understand the role that these defects and variants may play in predicting risk and optimizing patient management. The implications of coagulation genetics on the perioperative management of the cardiac surgery patient are reviewed.

Brain site-specific gene expression analysis in Alzheimer's disease patients

BACKGROUND

Alzheimer's disease (AD) is an age-related neurodegenerative disorder that is characterized by a progressive loss of higher cognitive functions. The brain of an individual with AD exhibits extracellular senile plaques (SPs) of aggregated amyloid-beta peptide (Abeta) and intracellular neurofibrillary tangles (NFTs). Given the critical role of neuronal transport of both proteins and organelles, it is not surprising that perturbation of microtubule-based transport may play a major role in the pathogenesis of AD.

MATERIALS AND METHODS

We used the cDNA subtraction methodology and in vitro neural cell culture analyses to study the meaning of the brain site-specific gene expression pattern in cerebral tissue obtained from AD patients and also from control subjects at autopsy.

RESULTS

We observed that cytoskeleton-associated proteins were down-regulated in AD subjects. We also noted an altered expression of the microtubule-associated protein 1B (MAP1B), the heat-shock protein (HSP)-90 (a key chaperone molecule), the tripartite motif-containing proteins (TRIM)-32/37 (an anti apoptotic enzyme with ubiquitin-protein ligase activity) and the Reticulon-3 (a modulator of the amyloid-precursor-protein (APP) cleavage) in AD brains. Additional molecular- and cell-biological studies revealed that small interfering RNA (siRNA)-mediated down-regulation of MAP1B expression leads to neuronal cell death in vitro.

CONCLUSION

Altered expression of MAP1B, HSP90, TRIM32/37 and Reticulon-3 provides new clues by which the ubiquitin-proteasome-, the protein-chaperon- and the APP-processing systems are disturbed in AD, thus, leading to neuritic amyloid plaques and neurofibrillary tangles.

Variations in the BDNF gene in autopsy-confirmed Alzheimer's disease and dementia with Lewy bodies in Japan

BACKGROUND/AIM

Brain-derived neurotrophic factor (BDNF) is associated with the hippocampus and the nigrostriatal dopaminergic function. Data showing that its level was reduced in Alzheimer's disease (AD) and Parkinson's disease (PD) suggested that the BDNF function must play an important role in the pathogenetics of these diseases. Indeed, variation in the BDNF gene may confer susceptibility to AD and PD development. Recently, a functional BDNF Val66Met polymorphism has been found to be associated with episodic memory and hippocampal function, with intracellular trafficking, and with activity-dependent secretion of BDNF. To date, there have been several conflicting reports on the correlation between AD or PD and Val66Met or C270T polymorphism in the BDNF promoter region, although no data on this relationship have been published with respect to dementia with Lewy bodies (DLB). In the present study, we investigated a possible association between such BDNF polymorphisms and susceptibility to AD or DLB.

METHODS

BDNF genotyping was carried out by the polymerase chain reaction-restriction fragment length polymorphism method in autopsy-confirmed human samples.

RESULTS AND CONCLUSION

On comparing patients and controls, the distribution of BDNF genotypes and alleles did not differ significantly. Our findings suggest that it is unlikely that these BDNF polymorphisms play a major role in the pathogenesis of AD and DLB in the Japanese population.