BACKGROUND: Myocardial infarction (MI) and underlining atherosclerosis are the main causes of death worldwide. Phosphatase and actin regulator 1 (PHACTR1) variants have been associated with early onset MI, coronary artery disease and carotid dissectio
n. PHACTR1 mRNA expression has been detected in tissues and cells related to atherosclerosis. Nonetheless, the true effect of PHACTR1 on vascular diseases is still unknown. Our aim was to examine the association of PHACTR1 intronic variants, rs9349379, rs2026458 and rs2876300, with MI and multi-vessel disease (MVD) and to assess their effect on PHACTR1 and EDN1 mRNA expression in PBMCs of patients six months after MI. METHODS: The study enrolled 537 patients with the first MI and 310 controls. Gene expression was assessed in 74 patients six months after MI and 37 healthy controls. Rs9349379, rs2026458, rs2876300 and relative mRNA expressions were detected by TaqMan® technology. RESULTS: The significant association between PHACTR1 variants and MI was not found, either individually or in haplotype. A higher frequency of rs2876300G-allele in MVD was rendered not significant after Bonferroni correction. PHACTR1 mRNA was significantly increased in PBMCs of patients six months after MI compared to controls (p = 0.02). Patients that carry ACG haplotype have increased PHACTR1 mRNA expression in PBMCs (p = 0.04). There was no effect of PHACTR1 variants on EDN1 mRNA expression. CONCLUSION: Our findings suggest that PHACTR1 intronic variants may have a role in severity and progression of coronary atherosclerosis. Future research is needed to clarify the mechanism underlying the role of PHACTR1 in coronary atherosclerosis and MI.
Kuveljic J, etal., Gene. 2019 Aug 20;710:273-278. doi: 10.1016/j.gene.2019.06.020. Epub 2019 Jun 12.
BACKGROUND: Carotid plaque is a hallmark of advanced carotid atherosclerosis and there is evidence of phosphatase and actin regulator 1 (PHACTR1) involvement in the processes that lead to atherosclerosis. PHACTR1
intronic variants have been associated with coronary artery disease and carotid dissection. Up to date the PHACTR1 haplotypes were not investigated in association with carotid plaque presence (CPP). So, the aims of this study were to investigate possible association of PHACTR1 haplotypes inferred from the intronic variants rs9349379, rs2026458 and rs2876300 with CPP in patients with advanced carotid atherosclerosis and to analyze their possible effect on PHACTR1 relative mRNA expression in carotid plaque tissue specimens. METHODS: The study group consisted of 501 patients with evidence of carotid plaque presence admitted for carotid endarterectomy and 310 healthy controls. PHACTR1 rs9349379, rs2026458, rs2876300 and relative mRNA expression were detected by TaqMan® technology. RESULTS: We have found significant and independent association of haplotype ACA with the CPP, compared to the referent haplotype GTA (adjusted OR = 1.54 95% CI = 1.07-2.21, p = 0.02). The OR was adjusted for gender, age, BMI, hypertension and total cholesterol. The relative expression of PHACTR1 mRNA in carotid plaque tissue proved to be significantly higher in carriers of the ACG haplotype compared to the referent haplotype GTA (p = 0.03). CONCLUSION: Our results suggest that PHACTR1 haplotypes inferred from the variants rs9349379, rs2026458 and rs2876300 affect PHACTR1 mRNA and bear the risk for CPP in patients with advanced carotid atherosclerosis. Further replication and validation studies are inevitable.
I have read with interest the recent paper by Han and coworkers on the putative effects of a PHACTR1 variant in the context of coronary artery disease. The authors conclude to a significant risk-enhancing role of rs12526453 on the grounds of 19 earlier case-cont
Yang Y, etal., PeerJ. 2020 May 5;8:e8841. doi: 10.7717/peerj.8841. eCollection 2020.
Moyamoya disease (MMD) is a progressive stenosis at the terminal portion of internal carotid artery and frequently occurs in East Asian countries. The etiology of MMD is still largely unknown. We performed a case-control design with whole-exome sequencing analysis on 31 sporadic MMD patients and 10
normal controls with matched age and gender. Patients clinically diagnosed with MMD was determined by digital subtraction angiography (DSA). Twelve predisposing mutations on seven genes associated with the sporadic MMD patients of Chinese ancestry (CCER2, HLA-DRB1, NSD-1, PDGFRB, PHACTR1, POGLUT1, and RNF213) were identified, of which eight single nucleotide variants (SNVs) were deleterious with CADD PHRED scaled score > 15. Sanger sequencing of nine cases with disease progression and 22 stable MMD cases validated that SNV (c.13185159G>T, p.V265L) on PHACTR1 was highly associated with the disease progression of MMD. Finally, we knocked down the expression of PHACTR1 by transfection with siRNA and measured the cell survival of human coronary artery endothelial cell (HCAEC) cells. PHACTR1 silence reduced the cell survival of HCAEC cells under serum starvation cultural condition. Together, these data identify novel predisposing mutations associated with MMD and reveal a requirement for PHACTR1 in mediating cell survival of endothelial cells.
Ma X, etal., Front Immunol. 2022 Aug 25;13:958677. doi: 10.3389/fimmu.2022.958677. eCollection 2022.
Genome-wide association studies (GWAS) have recently identified phosphatase and actin regulator-1 (PHACTR1) as a critical risk gene associated with polyvascular diseases. However, it remains largely unclear how PHACTR1 is in
volved in endothelial dysfunction. Here, by mining published datasets of human stable and vulnerable/ruptured plaque tissues, we observed upregulated expression of PHACTR1 in vulnerable/ruptured plaques. Congruent with these data, we demonstrated increased Phactr1 gene expression in aortic endothelium from ApoE-/- mice fed a western type diet compared with that in normal C57BL/6J mice. Relevantly, PHACTR1 gene expression was upregulated by pro-inflammatory and pro-atherogenic stimuli, including TNF-α, IL-1β and oxidized LDL (oxLDL). By employing next-generation RNA sequencing, we demonstrate that PHACTR1 overexpression disrupts pathways associated with endothelial homeostasis. Cell biological studies unravel that PHACTR1 mediates endothelial inflammation and monocyte adhesion by activating NF-κB dependent intercellular adhesion molecule 1 (ICAM1) and vascular cell adhesion molecule 1 (VCAM1) expression. In addition, overexpression of PHACTR1 also reduces the generation of nitric oxide (NO) by inhibiting Akt/eNOS activation. In-house compound screening of vasoprotective drugs identifies several drugs, including lipid-lowering statins, decreases PHACTR1 gene expression. However, PHACTR1 gene expression was not affected by another lipid-lowering drug-fenofibrate. We also performed a proteomic study to reveal PHACTR1 interacting proteins and validated that PHACTR1 can interact with heat shock protein A8 (HSPA8) which was reported to be associated with coronary artery disease and eNOS degradation. Further studies are warranted to confirm the precise mechanism of PHACTR1 in driving endothelial dysfunction. In conclusion, by using systems biology approach and molecular validation, we disclose the deleterious effects of PHACTR1 on endothelial function by inducing endothelial inflammation and reducing NO production, highlighting the potential to prevent endothelial dysfunction and atherosclerosis by targeting PHACTR1 expression. The precise role of endothelial cell PHACTR1 in polyvascular diseases remains to be validated in diseased conditions.
Hamada N, etal., Brain. 2018 Nov 1;141(11):3098-3114. doi: 10.1093/brain/awy246.
Trio-based whole exome sequencing identified two de novo heterozygous missense mutations [c.1449T > C/p.(Leu500Pro) and c.1436A > T/p.(Asn479Ile)] in PHACTR1, encoding a molecule critical for the regulation of protein phosphatase 1 (PP1) and the actin cytoskelet
on, in unrelated Japanese individuals with West syndrome (infantile spasms with intellectual disability). We then examined the role of Phactr1 in the development of mouse cerebral cortex and the pathophysiological significance of these two mutations and others [c.1561C > T/p.(Arg521Cys) and c.1553T > A/p.(Ile518Asn)], which had been reported in undiagnosed patients with intellectual disability. Immunoprecipitation analyses revealed that actin-binding activity of PHACTR1 was impaired by the p.Leu500Pro, p.Asn479Ile and p.Ile518Asn mutations while the p.Arg521Cys mutation exhibited impaired binding to PP1. Acute knockdown of mouse Phactr1 using in utero electroporation caused defects in cortical neuron migration during corticogenesis, which were rescued by an RNAi-resistant PHACTR1 but not by the four mutants. Experiments using knockdown combined with expression mutants, aimed to mimic the effects of the heterozygous mutations under conditions of haploinsufficiency, suggested a dominant negative effect of the mutant allele. As for dendritic development in vivo, only the p.Arg521Cys mutant was determined to have dominant negative effects, because the three other mutants appeared to be degraded with these experimental conditions. Electrophysiological analyses revealed abnormal synaptic properties in Phactr1-deficient excitatory cortical neurons. Our data show that the PHACTR1 mutations may cause morphological and functional defects in cortical neurons during brain development, which is likely to be related to the pathophysiology of West syndrome and other neurodevelopmental disorders.
PPP-family phosphatases such as PP1 have little intrinsic specificity. Cofactors can target PP1 to substrates or subcellular locations, but it remains unclear how they might confer sequence-specificity on PP1. The cytoskeletal regulator Phactr1 is a neuronally e
nriched PP1 cofactor that is controlled by G-actin. Structural analysis showed that Phactr1 binding remodels PP1's hydrophobic groove, creating a new composite surface adjacent to the catalytic site. Using phosphoproteomics, we identified mouse fibroblast and neuronal Phactr1/PP1 substrates, which include cytoskeletal components and regulators. We determined high-resolution structures of Phactr1/PP1 bound to the dephosphorylated forms of its substrates IRSp53 and spectrin αII. Inversion of the phosphate in these holoenzyme-product complexes supports the proposed PPP-family catalytic mechanism. Substrate sequences C-terminal to the dephosphorylation site make intimate contacts with the composite Phactr1/PP1 surface, which are required for efficient dephosphorylation. Sequence specificity explains why Phactr1/PP1 exhibits orders-of-magnitude enhanced reactivity towards its substrates, compared to apo-PP1 or other PP1 holoenzymes.
Green IE, etal., J Clin Neurosci. 2020 Apr;74:265-267. doi: 10.1016/j.jocn.2020.01.018. Epub 2020 Jan 21.
Variation in the phosphatase and actin regulator-1 (PHACTR1) gene, a downstream regulator of the endothelin-1 (EDN1) gene, has been implicated in the pathogenesis of several related vascular phenotypes including atherosclerotic coronary artery disease, non-ather
osclerotic coronary artery dissection, and carotid artery dissection, though it has not been studied in carotid atherosclerosis. We analyzed differential expression of PHACTR1 and EDN1 between atheromatous and non-atheromatous carotid artery tissue within the same individual and found lower levels of PHACTR1 expression in the atheromatous carotid tissue.
Wood A, etal., Cardiovasc Res. 2023 Mar 31;119(2):599-610. doi: 10.1093/cvr/cvac092.
AIMS: The non-coding locus at 6p24 located in Intron 3 of PHACTR1 has consistently been implicated as a risk allele in myocardial infarction and multiple other vascular diseases. Recent murine studies have identified a role for Phactr1
t:700;'>Phactr1 in the development of atherosclerosis. However, the role of PHACTR1 in vascular tone and in vivo vascular remodelling has yet to be established. The aim of this study was to investigate the role of PHACTR1 in vascular function. METHODS AND RESULTS: Prospectively recruited coronary artery disease (CAD) patients undergoing bypass surgery and retrospectively recruited spontaneous coronary artery dissection (SCAD) patients and matched healthy volunteers were genotyped at the PHACTR1 rs9349379 locus. We observed a significant association between the PHACTR1 loci and changes in distensibility in both the ascending aorta (AA = 0.0053 ± 0.0004, AG = 0.0041 ± 0.003, GG = 0.0034 ± 0.0009, P < 0.05, n = 58, 54, and 7, respectively) and carotid artery (AA = 12.83 ± 0.51, AG = 11.14 ± 0.38, GG = 11.69 ± 0.66, P < 0.05, n = 70, 65, and 18, respectively). This association was not observed in the descending aorta or in SCAD patients. In contrast, the PHACTR1 locus was not associated with changes in endothelial cell function with no association between the rs9349379 locus and in vivo or ex vivo vascular function observed in CAD patients. This finding was confirmed in our murine model where the loss of Phactr1 on the pro-atherosclerosis ApoE-/- background did not alter ex vivo vascular function. CONCLUSION: In conclusion, we have shown a role for PHACTR1 in arterial compliance across multiple vascular beds. Our study suggests that PHACTR1 has a key structural role within the vasculature.
Cervical artery dissection (CeAD), a mural hematoma in a carotid or vertebral artery, is a major cause of ischemic stroke in young adults although relatively uncommon in the general population (incidence of 2.6/100,000 per year). Minor cervical traumas, infection, migraine and hypertension are putat
ive risk factors, and inverse associations with obesity and hypercholesterolemia are described. No confirmed genetic susceptibility factors have been identified using candidate gene approaches. We performed genome-wide association studies (GWAS) in 1,393 CeAD cases and 14,416 controls. The rs9349379[G] allele (PHACTR1) was associated with lower CeAD risk (odds ratio (OR) = 0.75, 95% confidence interval (CI) = 0.69-0.82; P = 4.46 × 10(-10)), with confirmation in independent follow-up samples (659 CeAD cases and 2,648 controls; P = 3.91 × 10(-3); combined P = 1.00 × 10(-11)). The rs9349379[G] allele was previously shown to be associated with lower risk of migraine and increased risk of myocardial infarction. Deciphering the mechanisms underlying this pleiotropy might provide important information on the biological underpinnings of these disabling conditions.
Chen L, etal., Postgrad Med J. 2019 Feb;95(1120):67-71. doi: 10.1136/postgradmedj-2018-136298. Epub 2019 Feb 18.
BACKGROUND: Coronary artery disease (CAD) is the most frequent multifactorial disease worldwide and is characterised by endothelial injury, lipid deposition and coronary artery calcification. The purpose of this study was to determine the allelic and genotypic frequencies of two loci (rs2
026458 and rs9349379) of phosphatase and actin regulator 1 (PHACTR1) to the risk of developing CAD in the Chinese Han population. METHODS: A case-control study was conducted including 332 patients with CAD and 119 controls. Genotype analysis was performed by PCR and Sanger sequencing. Genetic model analysis was performed to evaluate the association between single nucleotide polymorphisms and CAD susceptibility using Pearson's χ2 test and logistic regression analysis. RESULTS: The GG genotype of rs9349379 represented 50% and 29% of patients with CAD and controls, respectively (p<0.001). The CC genotype of rs2026458 was more prevalent in the controls than in patients with CAD compared with TT genotype (OR=0.548, 95% CI 0.351 to 0.856, p=0.008). Logistic regression analyses revealed that PHACTR1 rs9349379 GG genotype was significantly associated with increased risk of CAD in the recessive model (OR=2.359, 95% CI 1.442 to 3.862, p=0.001), even after adjusting for age gender, hypertension, type 2 diabetes, hyperlipidaemia and smoking habit. Heterogeneity test proved that rs9349379's risk effects on CAD were more significant among women. CONCLUSIONS: Our study indicate that the PHACTR1 rs9349379 polymorphism is associated with the increased risk for CAD in the female Chinese Han population.
BACKGROUND: Familial hypercholesterolemia (FH) is the most frequent autosomal codominant disease worldwide and is characterized by elevated low-density lipoprotein cholesterol and premature coronary artery disease (CAD). Polymorphisms in phosphatase and actin regulator 1 (PHACTR1
t-weight:700;'>PHACTR1) have been shown to be associated with cardiovascular risk in large genome-wide association studies studies. OBJECTIVE: The aim of the present study is to evaluate the association between the rs12526453 polymorphism in the PHACTR1 gene and the prevalence of CAD in FH patients. METHODS: A cohort of 668 adult genetically confirmed heterozygous FH subjects were included in the present study. Logistic regression models were used to evaluate the strength of the association between rs12526453 genotype and CAD prevalence. RESULTS: Noncarriers (CC) of the rs12526453 represented 41% of the cohort, whereas heterozygous (CG) and homozygous (GG) carriers represented 44% and 15%, respectively. The prevalence of CAD was significantly higher in non-carriers of the rs12526453 polymorphism compared to heterozygous and homozygous carriers (38.0%, 25.8%, 24.5%, respectively, P = .001). When a dominant logistic regression model was studied, the association between this single-nucleotide polymorphism and CAD prevalence was significant even after correction for all classical cardiovascular risk factors (odds ratio 0.48, 95% confidence intervals 0.31-0.74, P = .001). CONCLUSION: In the present study, we have shown that the rs12526453 single-nucleotide polymorphism of the PHACTR1 gene is significantly associated with a 50% reduction in the odds of CAD events in FH subjects. Because the protective G allele is frequent in the Caucasian population (allelic frequency of 0.26), screening for this polymorphism in Caucasian FH subjects could further help to stratify risk of CAD in this population.
BACKGROUND AND AIMS: Coronary artery disease (CAD) risk is associated with non-coding genetic variants at the phosphatase and actin regulating protein 1(PHACTR1) gene locus. The PHACTR1 gene encodes an actin-bindi
ng protein with phosphatase regulating activity. The mechanism whereby PHACTR1 influences CAD risk is unknown. We hypothesized that PHACTR1 would be expressed in human cell types relevant to CAD and regulated by atherogenic or genetic factors. METHODS AND RESULTS: Using immunohistochemistry, we demonstrate that PHACTR1 protein is expressed strongly in human atherosclerotic plaque macrophages, lipid-laden foam cells, adventitial lymphocytes and endothelial cells. Using a combination of genomic analysis and molecular techniques, we demonstrate that PHACTR1 is expressed as multiple previously uncharacterized transcripts in macrophages, foam cells, lymphocytes and endothelial cells. Immunoblotting confirmed a total absence of PHACTR1 in vascular smooth muscle cells. Real-time quantitative PCR showed that PHACTR1 is regulated by atherogenic and inflammatory stimuli. In aortic endothelial cells, oxLDL and TNF-alpha both upregulated an intermediate length transcript. A short transcript expressed only in immune cells was upregulated in macrophages by oxidized low-density lipoprotein, and oxidized phospholipids but suppressed by lipopolysaccharide or TNF-alpha. In primary human macrophages, we identified a novel expression quantitative trait locus (eQTL) specific for this short transcript, whereby the risk allele at CAD risk SNP rs9349379 is associated with reduced PHACTR1 expression, similar to the effect of an inflammatory stimulus. CONCLUSIONS: Our data demonstrate that PHACTR1 is a key atherosclerosis candidate gene since it is regulated by atherogenic stimuli in macrophages and endothelial cells and we identify an effect of the genetic risk variant on PHACTR1 expression in macrophages that is similar to that of an inflammatory stimulus.
Genetic variants in phosphatase and actin regulator-1 (Phactr1) are reported to be associated with arteriosclerotic cardiovascular disease (ASCVD). However, the function of Phactr1 in atherosclerosis remains unclear. Patient
s with acute coronary syndrome (ACS) who underwent coronary angiography and optical coherence tomography (OCT) were enrolled and divided into non-ST segment elevation (NST-ACS) group and ST-ACS group. The expression of Phactr1 on monocytes was higher in NST-ACS and ST-ACS groups as compared with control group. Furthermore, NST-ACS patients who have more vulnerable features including thin-cap fibroatheroma (TCFA) and large lipid area showed higher levels of Phactr1 on monocytes than those with stable plaques. Through mouse models of atherosclerosis, Phactr1-/-Apoe-/- mice (double knockout mice, DKO) developed more severe atherosclerotic plaques, recruiting more macrophages into subendothelium and having elevated levels of proinflammatory cytokines in plaques. Similarly, Apoe knockout mice (Apoe-/-) receiving DKO bone marrow (BM) exhibited elevated plaque burden compared with Apoe-/- mice receiving Apoe-/- BM, indicating the protective effect of Phactr1 in hematopoietic cells. We found that depletion of Phactr1 in BM-derived macrophages (BMDMs) tended to differentiate into M1 phenotype, produced more proatherogenic cytokines and eventually converted into foam cells driven by oxidized low-density lipoprotein (ox-LDL). Mechanistically, Phactr1 activated CREB signaling via directly binding to CREB, up-regulating CREB phosphorylation and inducing KLF4 expression. Finally, overexpression of KLF4 partly rescued the excessive inflammation response and foam cell formation induced by deficiency of Phactr1. In conclusion, our study demonstrates that elevated Phactr1 in monocytes is a promising biomarker for vulnerable plaques, while increased Phactr1 attenuates atherosclerotic development via activation of CREB and M2 macrophage differentiation.
The manifestation of coronary artery disease (CAD) follows a well-choreographed series of events that includes damage of arterial endothelial cells and deposition of lipids in the sub-endothelial layers. Genome-wide association studies (GWAS) of multiple populations with distinctive genetic and life
style backgrounds are a crucial step in understanding global CAD pathophysiology. In this study, we report a GWAS on the genetic basis of arterial stenosis as measured by cardiac catheterization in a Lebanese population. The locus of the phosphatase and actin regulator 1 gene (PHACTR1) showed association with coronary stenosis in a discovery experiment with genome wide data in 1,949 individuals (rs9349379, OR = 1.37, p = 1.57×10(-5)). The association was replicated in an additional 2,547 individuals (OR = 1.31, p = 8.85×10(-6)), leading to genome-wide significant association in a combined analysis (OR = 1.34, p = 8.02×10(-10)). Results from this GWAS support a central role of PHACTR1 in CAD susceptibility irrespective of lifestyle and ethnic divergences. This association provides a plausible component for understanding molecular mechanisms involved in the formation of stenosis in cardiac vessels and a potential drug target against CAD.
OBJECTIVE: Coronary artery disease (CAD), including myocardial infarction (MI), is the main cause of death in the world. Genome-wide association studies have identified dozens of single nucleotide polymorphisms (SNPs) associated with CAD/MI. One of the most robust CAD/MI genetic associations is with
intronic SNPs in the gene PHACTR1 on chromosome 6p24. How these PHACTR1 SNPs influence CAD/MI risk, and whether PHACTR1 itself is the causal gene at the locus, is currently unknown. APPROACH AND RESULTS: Using genetic fine-mapping and DNA resequencing experiments, we prioritized an intronic SNP (rs9349379) in PHACTR1 as causal variant. We showed that this variant is an expression quantitative trait locus for PHACTR1 expression in human coronary arteries. Experiments in endothelial cell extracts confirmed that alleles at rs9349379 are differentially bound by the transcription factors myocyte enhancer factor-2. We engineered a deletion of this myocyte enhancer factor-2-binding site using CRISPR/Cas9 genome-editing methodology. Heterozygous endothelial cells carrying this deletion express 35% less PHACTR1. Finally, we found no evidence that PHACTR1 expression levels are induced when stimulating human endothelial cells with vascular endothelial growth factor, tumor necrosis factor-alpha, or shear stress. CONCLUSIONS: Our results establish a link between intronic SNPs in PHACTR1, myocyte enhancer factor-2 binding, and transcriptional functions at the locus, PHACTR1 expression levels in coronary arteries and CAD/MI risk. Because PHACTR1 SNPs are not associated with the traditional risk factors for CAD/MI (eg, blood lipids or pressure, diabetes mellitus), our results suggest that PHACTR1 may influence CAD/MI risk through as yet unknown mechanisms in the vascular endothelium.
Zhao Q, etal., Oncotarget. 2017 Jan 3;8(1):658-663. doi: 10.18632/oncotarget.13506.
Previous studies showed that PHACTR1 and SLC22A3 are involved in coronary vascular development and are key determinants of cardiovascular disease risk. We conducted a case-control study to examine the effect of SLC22A3 and PHACTR1
/span> single nucleotide polymorphisms (SNPs) on CAD risk among 376 male CAD patients and 388 male healthy controls from China. Eleven SLC22A3 and PHACTR1 SNPs were selected and genotyped using Sequenom Mass-ARRAY technology. Odds ratios (OR) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression adjusting for age. The rs9381439 minor allele "A" (OR = 0.72; 95% CI = 0.54-0.96; p = 0.024) in an allelic model was associated with reduced CAD risk, as were the rs2048327 "C/C" (OR = 0.60; 95% CI: 0.37-0.97; p = 0.036) and rs1810126 "T/T" (OR = 0.58; 95% CI: 0.36-0.93; p = 0.024) genotypes. Likewise, the rs9349379 "A/G" genotype in a dominant model (p = 0.041), the rs1810126 "T/C" genotype in additive (p = 0.041) and recessive (p = 0.012) models, and the rs2048327 "C/T" genotype in a recessive model were associated with decreased CAD risk (p = 0.016). These results suggest several PHACTR1 and SLC22A3 polymorphisms are associated with decreased CAD risk in the male Chinese Han population.
Pérez-Hernández N, etal., Int J Environ Res Public Health. 2016 Aug 9;13(8):803. doi: 10.3390/ijerph13080803.
Single-nucleotide polymorphisms (SNPs) in the protein phosphatase and actin regulator 1 gene (PHACTR1) have been associated with susceptibility to develop several diseases, including cardiovascular disease. The purpose of this study was to evaluate the role of t
wo polymorphisms (rs2026458 and rs9349379) of the PHACTR1 gene in the susceptibility to the risk of developing premature coronary artery disease (CAD) in the Mexican population. The genotype analysis was performed using 5'exonuclease TaqMan genotyping assays in a group of 994 patients with premature CAD and 703 controls. A similar genotype distribution of rs2026458 was observed in both groups; however, under an additive model adjusted by age, body mass index, type 2 diabetes mellitus, smoking, dyslipidemia, and hypertension, the rs9349379 G allele was associated with a higher risk for developing premature CAD (odds ratio (OR) = 1.22, 95% confidence interval (CI) = 1.03-1.46, p-value (p) = 0.024). The two PHACTR1 polymorphisms were not in linkage disequilibrium. In summary, our results suggest that the PHACTR1 rs9349379 polymorphism plays an important role in the risk of developing premature CAD in the Mexican population.
Fibromuscular dysplasia (FMD) is a nonatherosclerotic vascular disease leading to stenosis, dissection and aneurysm affecting mainly the renal and cerebrovascular arteries. FMD is often an underdiagnosed cause of hypertension and stroke, has higher prevalence in females (~80%) but its pathophysiolog
y is unclear. We analyzed ~26K common variants (MAF>0.05) generated by exome-chip arrays in 249 FMD patients and 689 controls. We replicated 13 loci (P<10-4) in 402 cases and 2,537 controls and confirmed an association between FMD and a variant in the phosphatase and actin regulator 1 gene (PHACTR1). Three additional case control cohorts including 512 cases and 669 replicated this result and overall reached the genomic level of significance (OR = 1.39, P = 7.4×10-10, 1,154 cases and 3,895 controls). The top variant, rs9349379, is intronic to PHACTR1, a risk locus for coronary artery disease, migraine, and cervical artery dissection. The analyses of geometrical parameters of carotids from ~2,500 healthy volunteers indicate higher intima media thickness (P = 1.97×10-4) and wall to lumen ratio (P = 0.002) in rs9349379-A carriers, suggesting indices of carotid hypertrophy previously described in carotids of FMD patients. Immunohistochemistry detected PHACTR1 in endothelium and smooth muscle cells of FMD and normal human carotids. The expression of PHACTR1 by genotypes in primary human fibroblasts showed higher expression in rs9349379-A carriers (N = 86, P = 0.003). Phactr1 knockdown in zebrafish resulted in dilated vessels indicating subtle impaired vascular development. We report the first susceptibility locus for FMD and provide evidence for a complex genetic pattern of inheritance and indices of shared pathophysiology between FMD and other cardiovascular and neurovascular diseases.
Mouilleron S, etal., Structure. 2012 Nov 7;20(11):1960-70. doi: 10.1016/j.str.2012.08.031. Epub 2012 Oct 4.
The Phactr family of PP1-binding proteins and the myocardin-related transcription factor family of transcriptional coactivators contain regulatory domains comprising three copies of the RPEL motif, a G-actin binding element. We report the structure of a Phactr1
G-actinRPEL domain complex. Three G-actins surround the crank-shaped RPEL domain forming a closed helical assembly. Their spatial relationship is identical to the RPEL-actins within the pentavalent MRTF G-actinRPEL domain complex, suggesting that conserved cooperative interactions between actinRPEL units organize the assembly. In the trivalent Phactr1 complex, each G-actinRPEL unit makes secondary contacts with its downstream actin involving distinct RPEL residues. Similar secondary contacts are seen in G-actinRPEL peptide crystals. Loss-of-secondary-contact mutations destabilize the Phactr1 G-actinRPEL assembly. Furthermore, actin-mediated inhibition of Phactr1 nuclear import requires secondary contact residues in the Phactr1 N-terminal RPEL-N motif, suggesting that it involves interaction of RPEL-N with the C-terminal assembly. Secondary actin contacts by actin-bound RPEL motifs thus govern formation of multivalent actinRPEL assemblies.
Kelloniemi A, etal., PLoS One. 2015 Jun 22;10(6):e0130502. doi: 10.1371/journal.pone.0130502. eCollection 2015.
The phosphatase and actin regulator 1 (PHACTR1) locus is a very commonly identified hit in genome-wide association studies investigating coronary artery disease and myocardial infarction (MI). However, the function of PHACTR1
> in the heart is still unknown. We characterized the mechanisms regulating Phactr1 expression in the heart, used adenoviral gene delivery to investigate the effects of Phactr1 on cardiac function, and analyzed the relationship between MI associated PHACTR1 allele and cardiac function in human subjects. Phactr1 mRNA and protein levels were markedly reduced (60%, P<0.01 and 90%, P<0.001, respectively) at 1 day after MI in rats. When the direct myocardial effects of Phactr1 were studied, the skeletal alpha-actin to cardiac alpha-actin isoform ratio was significantly higher (1.5-fold, P<0.05) at 3 days but 40% lower (P<0.05) at 2 weeks after adenovirus-mediated Phactr1 gene delivery into the anterior wall of the left ventricle. Similarly, the skeletal alpha-actin to cardiac alpha-actin ratio was lower at 2 weeks in infarcted hearts overexpressing Phactr1. In cultured neonatal cardiac myocytes, adenovirus-mediated Phactr1 overexpression for 48 hours markedly increased the skeletal alpha-actin to cardiac alpha-actin ratio, this being associated with an enhanced DNA binding activity of serum response factor. Phactr1 overexpression exerted no major effects on the expression of other cardiac genes or LV structure and function in normal and infarcted hearts during 2 weeks' follow-up period. In human subjects, MI associated PHACTR1 allele was not associated significantly with cardiac function (n = 1550). Phactr1 seems to regulate the skeletal to cardiac alpha-actin isoform ratio.
Szpakowicz A, etal., PLoS One. 2015 Jun 18;10(6):e0129820. doi: 10.1371/journal.pone.0129820. eCollection 2015.
OBJECTIVE: The rs12526453 (C/G) is a single nucleotide polymorphism in an intron of the PHACTR1 gene (phosphatase and actin regulator 1). The C allele is associated with increased risk of coronary artery disease in an unknown mechanism. We investigated its asso
ciation with long-term overall mortality in patients with ST-elevation myocardial infarction (STEMI) treated invasively. METHODS: Two independent groups of patients with STEMI were analyzed: a derivation group (n= 638) and a validation one (n=348). Genotyping was performed with the TaqMan method. The analyzed end-point was total long term mortality. Additionally, transcriptomic analysis was performed in mononuclear blood leukocytes from rs12526453 CC monozygotes or G allele carriers. RESULTS: In the study group (mean age 62.3 +/- 11.9 years; 24.9% of females, n=159), percentages of CC, CG, and GG genotypes were 45.3% (n=289), 44.7% (n=285), and 10% (n=64), respectively. In the 5-year follow-up 105 patients died (16.46%). CC homozygotes had significantly lower mortality compared to other genotypes: 13.1% (n=38) vs. 18.3% in G-allele carriers (n=67), (p=0.017, Cox`s F test). In the validation group 47 patients died within 3 years (13.5%). We confirmed lower mortality of CC homozygotes: 10.1 % (n=18) vs. 16.95% in G-allele carriers (n=29), (p=0.031, Cox`s F test). Transcriptomic analysis revealed a markedly higher expression of NLRP-2 in CC homozygotes. CONCLUSIONS: The rs12526453 CC homozygotes (previously associated with increased risk of myocardial infarction) showed, in 2 independent samples, better long-term survival. The finding of such high effect size, after appropriate validation, could potentially be translated into clinical practice.
