Functional SNP in an Sp1-binding site of AGTRL1 gene is associated with susceptibility to brain infarction

Impact of the apelin/APJ axis in the pathogenesis of Parkinson's disease with therapeutic potential

The pathogenesis of Parkinson's disease (PD) remains elusive. There is still no available disease-modifying strategy against PD, whose management is mainly symptomatic. A growing amount of preclinical evidence shows that a complex interplay between autophagy dysregulation, mitochondrial impairment, endoplasmic reticulum stress, oxidative stress, and excessive neuroinflammation underlies PD pathogenesis. Identifying key molecules linking these pathological cellular processes may substantially aid in our deeper understanding of PD pathophysiology and the development of novel effective therapeutic approaches. Emerging preclinical evidence indicates that apelin, an endogenous neuropeptide acting as a ligand of the orphan G protein-coupled receptor APJ, may play a key neuroprotective role in PD pathogenesis, via inhibition of apoptosis and dopaminergic neuronal loss, autophagy enhancement, antioxidant effects, endoplasmic reticulum stress suppression, as well as prevention of synaptic dysregulation in the striatum, excessive neuroinflammation, and glutamate-induced excitotoxicity. Underlying signaling pathways involve phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin, extracellular signal-regulated kinase 1/2, and inositol requiring kinase 1α/XBP1/C/EBP homologous protein. Herein, we discuss the role of apelin/APJ axis and associated molecular mechanisms on the pathogenesis of PD in vitro and in vivo and provide evidence for its challenging therapeutic potential.

Neuroprotective gain of Apelin/APJ system

Apelin is an endogenous ligand of G protein-coupled receptor APJ. In recent years, many studies have shown that the apelin/APJ system has neuroprotective properties, such as anti-inflammatory, anti-oxidative stress, anti-apoptosis, and regulating autophagy, blocking excitatory toxicity. Apelin/APJ system has been proven to play a role in various neurological diseases and may be a promising therapeutic target for nervous system diseases. In this paper, the neuroprotective properties of the apelin/APJ system and its role in neurologic disorders are reviewed. Further understanding of the pathophysiological effect and mechanism of the apelin/APJ system in the nervous system will help develop new therapeutic interventions for various neurological diseases.

Mutations in cis that affect mRNA synthesis, processing and translation

Genetic mutations that cause hereditary diseases usually affect the composition of the transcribed mRNA and its encoded protein, leading to instability of the mRNA and/or the protein. Sometimes, however, such mutations affect the synthesis, the processing or the translation of the mRNA, with similar disastrous effects. We here present an overview of mRNA synthesis, its posttranscriptional modification and its translation into protein. We then indicate which elements in these processes are known to be affected by pathogenic mutations, but we restrict our review to mutations in cis, in the DNA of the gene that encodes the affected protein. These mutations can be in enhancer or promoter regions of the gene, which act as binding sites for transcription factors involved in pre-mRNA synthesis. We also describe mutations in polyadenylation sequences and in splice site regions, exonic and intronic, involved in intron removal. Finally, we include mutations in the Kozak sequence in mRNA, which is involved in protein synthesis. We provide examples of genetic diseases caused by mutations in these DNA regions and refer to databases to help identify these regions. The over-all knowledge of mRNA synthesis, processing and translation is essential for improvement of the diagnosis of patients with genetic diseases.

Molecular signatures of selection on the human GLI3 associated central nervous system specific enhancers

The zinc finger-containing transcription factor Gli3 is a key mediator of Hedgehog (Hh) signaling pathway. In vertebrates, Gli3 has widespread expression pattern during early embryonic development. Along the anteroposterior axes of the central nervous system (CNS), dorsoventral neural pattern elaboration is achieved through Hh mediated spatio-temporal deployment of Gli3 transcripts. Previously, we and others uncovered a set of enhancers that mediate many of the known aspects of Gli3 expression during neurogenesis. However, the potential role of Gli3 associated enhancers in trait evolution has not yet received any significant attention. Here, we investigate the evolutionary patterns of Gli3 associated CNS-specific enhancers that have been reported so far. A subset of these enhancers has undergone an accelerated rate of molecular evolution in the human lineage in comparison to other primates/mammals. These fast-evolving enhancers have acquired human-specific changes in transcription factor binding sites (TFBSs). These human-unique changes within subset of Gli3 associated CNS-specific enhancers were further validated as single nucleotide polymorphisms through 1000 Genome Project Phase 3 data. This work not only infers the molecular evolutionary patterns of Gli3 associated enhancers but also provides clues for putative genetic basis of the population-specificity of gene expression regulation.

Transcriptome Response and Spatial Pattern of Gene Expression in the Primate Subventricular Zone Neurogenic Niche After Cerebral Ischemia

The main stem cell niche for neurogenesis in the adult mammalian brain is the subventricular zone (SVZ) that extends along the cerebral lateral ventricles. We aimed at characterizing the initial molecular responses of the macaque monkey SVZ to transient, global cerebral ischemia. We microdissected tissue lining the anterior horn of the lateral ventricle (SVZa) from 7 day post-ischemic and sham-operated monkeys. Transcriptomics shows that in ischemic SVZa, 541 genes were upregulated and 488 genes were down-regulated. The transcription data encompassing the upregulated genes revealed a profile typical for quiescent stem cells and astrocytes. In the primate brain the SVZ is morphologically subdivided in distinct and separate ependymal and subependymal regions. The subependymal contains predominantly neural stem cells (NSC) and differentiated progenitors. To determine in which SVZa region ischemia had evoked transcriptional upregulation, sections through control and ischemic SVZa were analyzed by high-throughput in situ hybridization for a total of 150 upregulated genes shown in the www.monkey-niche.org image database. The majority of the differentially expressed genes mapped to the subependymal layers on the striatal or callosal aspect of the SVZa. Moreover, a substantial number of upregulated genes was expressed in the ependymal layer, implicating a contribution of the ependyma to stem cell biology. The transcriptome analysis yielded several novel gene markers for primate SVZa including the apelin receptor that is strongly expressed in the primate SVZa niche upon ischemic insult.

Vascular homeostasis at high-altitude: role of genetic variants and transcription factors

High-altitude pulmonary edema occurs most frequently in non-acclimatized low landers on exposure to altitude ≥2500 m. High-altitude pulmonary edema is a complex condition that involves perturbation of signaling pathways in vasoconstrictors, vasodilators, anti-diuretics, and vascular growth factors. Genetic variations are instrumental in regulating these pathways and evidence is accumulating for a role of epigenetic modification in hypoxic responses. This review focuses on the crosstalk between high-altitude pulmonary edema-associated genetic variants and transcription factors, comparing high-altitude adapted and high-altitude pulmonary edema-afflicted subjects. This approach might ultimately yield biomarker information both to understand and to design therapies for high-altitude adaptation.

Apelin inhibits an endothelium-derived hyperpolarizing factor-like pathway in rat cerebral arteries

Apelin has complex vasomotor actions inasmuch as the peptide may cause either vasodilation or vasoconstriction depending on the vascular bed and experimental conditions. In cerebral arteries, apelin inhibits endothelium-dependent relaxations mediated by nitric oxide (NO); however, its effects on relaxation to other endothelium-derived substances (e.g. prostacyclin, endothelium-derived hyperpolarizing factors(s) (EDHF)) are unknown. The present study was designed to determine effects of apelin on endothelium-dependent relaxations that are independent of NO in rat cerebral arteries. In arterial rings contracted with 5-HT, A23187 caused endothelium-dependent relaxation that was unaffected by inhibitors of eNOS, guanylyl cyclase or cyclooxygenase, but was attenuated by MS-PPOH, a selective inhibitor of cytochrome P450 catalyzed synthesis of epoxyeicosatrienoic acids (EETs) and by 14,15-EE(Z)E, an EET-receptor antagonist. Apelin inhibited A23187-induced relaxation, as well as relaxations evoked by exogenous 11,12- and 14,15-EET. These effects of apelin were mimicked by the selective BK_Ca channel blocker, iberiotoxin. The APJ receptor antagonist, F13A abolished the effects of apelin on A23187-induced relaxations. Both 11,12- and 14,15-EET also increased BK_Ca channel current density in isolated cerebral artery smooth muscle cells, effects that were inhibited in a similar manner by apelin and iberiotoxin. These findings provide evidence that apelin impairs endothelium-dependent relaxation of cerebral arteries by inhibiting an NO-independent pathway (i.e. "EDHF-like") involving activation of smooth muscle cell BK_Ca channels by endothelium-derived EETs. Inhibition of such pathway may create an environment favoring vasoconstriction in cerebral arteries.

Association of Apelin and Apelin Receptor Polymorphisms With the Risk of Comorbid Depression and Anxiety in Coronary Heart Disease Patients

The Apelin (APLN)/apelin receptor (APLNR) signaling pathway is a newly identified regulator in various cardiovascular diseases, which is considered as a candidate pathway for the occurrence of coronary heart disease (CHD), depression, and anxiety. The goal of this study was to investigate the association between APLN/APLNR gene polymorphisms and the risk of depression and anxiety in CHD patients. To this end, a case-control study involving 269 CHD patients and 184 healthy control individuals was conducted. The 269 patients with CHD including 122 patients with and 147 patients without depression, and 56 patients with and 213 patients without anxiety Four single nucleotide polymorphisms were selected and successfully genotyped using Sanger sequencing. The APLN rs2235310T allele and APLNR rs9943582C allele were found to be associated with an increased risk of CHD after multiple test correction (P-adjust < 0.05). The patients with CHD who carried the rs9943582C allele had a higher risk of depression, after adjusting for alcohol drinking habits, insomnia, hypertension, and stroke history, with the Bonferroni correction (P-adjust = 0.018). The APLNR rs2282623 T allele was associated with an increased risk of anxiety in CHD patients after adjusting for related disease complications, with the Bonferroni correction (P-adjust = 0.022). We reported for the first time that the APLN rs2235310 and APLNR rs2282623 polymorphisms are associated with the risks of psychiatric disorders in CHD patients and may serve as novel biomarkers for therapy.

The Apelin/APJ System in Psychosis and Neuropathy

Apelin, an endogenous neuropeptide, has been identified as the cognate ligand for the G-protein-coupled receptor APJ. Apelin, APJ messenger RNA, and protein are widely expressed in the central nervous system and peripheral tissues of humans and animals. The apelin/APJ system has been implicated in diverse physiological and pathological processes. The present article reviews the progress of the latest research investigating the apelin/APJ system in pain, depression, anxiety, memory, epilepsy, neuroprotection, stroke, and brain injury and protection, and highlights its promising potential as a therapeutic target for treatment of psychosis and neuropathy.

The Protective Effects and Mechanisms of Apelin/APJ System on Ischemic Stroke: A Promising Therapeutic Target

The orphan receptor APJ and its endogenous ligand apelin, which are expressed in the brain, are the major components of the apelin/APJ system. Growing evidence shows that the apelin/APJ system plays a vital role in the pathophysiology of cerebral ischemic injury. Targeting the apelin/APJ system may have protective effects on cerebral ischemic injury. In this review, we sum up the latest research progress relating to the actions and therapeutic potential of the apelin/APJ system in ischemic stroke. An in-depth knowledge of the pathophysiological effects of the apelin/APJ system and the underlying mechanisms will help to develop novel therapeutic interventions for ischemic stroke.

Establishing molecular signatures of stroke focusing on omic approaches: a narrative review

Stroke or 'brain attack' is considered to be the major cause of mortality and morbidity worldwide after myocardial infraction. Inspite of the years of research and clinical practice, the pathogenesis of stroke still remains incompletely understood. Omics approaches not only enable the description of a huge number of molecular platforms but also have a potential to recognize new factors associated with various complex disorders including stroke. The most significant development among all other omics technologies over the recent years has been seen by genomics which is a powerful tool for exploring the genetic architecture of stroke. Genomics has decisively established itself in stroke research and by now wealth of data has been generated providing new insights into the physiology and pathophysiology of stroke. However, the efficacy of genomic data is restricted to risk prediction only. Omics approaches not only enable the description of a huge number of molecular platforms but also have a potential to recognize new factors associated with various complex disorders including stroke. The data generated by omics technologies enables clinicians to provide detailed insight into the makeup of stroke in individual patients, which will further help in developing diagnostic procedures to direct therapies. Present review has been compiled with an aim to understand the potential of integrated omics approach to help in characterization of mechanisms leading to stroke, to predict the patient risk of getting stroke by analyzing signature biomarkers and to develop targeted therapeutic strategies.

The influence of post-infarct heart failure and high fat diet on the expression of apelin APJ and vasopressin V1a and V1b receptors

Vasopressin and apelin are reciprocally regulated hormones which are implicated in the pathophysiology of heart failure and the regulation of metabolism; however, little is known about their interactions under pathological conditions. In this study, we determined how post-infarct heart failure (HF) and a high fat diet (HFD) affect expression of the apelin APJ receptor (APJR) and the V1a (V1aR) and V1b (V1bR) vasopressin receptors in the hypothalamus, the heart, and the retroperitoneal adipose tissue. We performed experiments in male 4-week-old Sprague Dawley rats. The animals received either a normal fat diet (NFD) or a HFD for 8 weeks, then they underwent left coronary artery ligation to induce HF or sham surgery (SO), followed by 4 weeks of NFD or HFD. The HF rats showed higher plasma concentration of NT-proBNP and copeptin. The HF reduced the APJR mRNA expression in the hypothalamus. The APJR and V1aR protein levels in the hypothalamus were regulated both by HF and HFD, while the V1bR protein level in the hypothalamus was mainly influenced by HF. APJR mRNA expression in the heart was significantly higher in rats on HFD, and HFD affected the reduction of the APJR protein level in the right ventricle. The regulation of APJR, V1aR and V1bR expression in the heart and the retroperitoneal adipose tissue were affected by both HF and HFD. Our study demonstrates that HF and HFD cause significant changes in the expression of APJR, V1aR and V1bR, which may have an important influence on the cardiovascular system and metabolism.

Interaction between COX-1 and COX-2 increases susceptibility to ischemic stroke in a Chinese population

Background

Mutations of cyclooxygenase gene (COX gene) may increase the susceptibility of ischemic stroke. We investigated five variants (rs5788, rs1330344, rs3842788, rs20417, and rs689466) of two COX genes in order to explaining the association between these polymorphisms and we also investigated the association between these variants and ischemic stroke risk to determine whether gene–gene interaction between these genes increases the susceptibility of ischemic stroke or its subtypes.

Methods

A total of 1981 study subjects (1078 cases and 903 control subjects) were recruited. The interaction of multiple factors was investigated using Multifactor Dimensionality Reduction. The additive effect of single nucleotide polymorphisms on ischemic stroke or its subtypes were analyzed by multiple factor logistic regression.

Results

At COX-1(rs1330344), AA genotype carriers had a lower susceptibility of ischemic stroke (OR = 0.657, 95%CI = 0.437–0.988, P = 0.044), and A allele carriers had a lower susceptibility of ischemic stroke (OR = 0.812, 95%CI = 0.657–0.978, P = 0.029). At COX-1(rs3842788), AA genotype carriers had a higher susceptibility of ischemic stroke (OR = 5.203, 95% CI = 1.519–5.159, P = 0.016). At COX-2 (rs689466), AA genotype carriers had a higher susceptibility of large-artery atherosclerosis (OR = 1.404, 95% CI = 1.019–1.934, P = 0.038). COX-1(rs1330344, rs3842788) and COX-2 rs689466 interacted in SVO, but had no additive effect with ischemic stroke and other subtypes.

Conclusions

At rs1330344, AA genotype may reduce the susceptibility of ischemic stroke. At rs3842788, AA genotype may increase the susceptibility of ischemic stroke. At rs689466, AA genotype may increase the susceptibility of large-artery atherosclerosis (LAA). COX − 1(rs1330344, rs3842788) and COX-2 rs689466 interacted in small vessel occlusion (SVO), but had no additive effect with ischemic stroke and other subtypes.

International Union of Basic and Clinical Pharmacology. CVII. Structure and Pharmacology of the Apelin Receptor with a Recommendation that Elabela/Toddler Is a Second Endogenous Peptide Ligand

The predicted protein encoded by the APJ gene discovered in 1993 was originally classified as a class A G protein-coupled orphan receptor but was subsequently paired with a novel peptide ligand, apelin-36 in 1998. Substantial research identified a family of shorter peptides activating the apelin receptor, including apelin-17, apelin-13, and [Pyr1]apelin-13, with the latter peptide predominating in human plasma and cardiovascular system. A range of pharmacological tools have been developed, including radiolabeled ligands, analogs with improved plasma stability, peptides, and small molecules including biased agonists and antagonists, leading to the recommendation that the APJ gene be renamed APLNR and encode the apelin receptor protein. Recently, a second endogenous ligand has been identified and called Elabela/Toddler, a 54-amino acid peptide originally identified in the genomes of fish and humans but misclassified as noncoding. This precursor is also able to be cleaved to shorter sequences (32, 21, and 11 amino acids), and all are able to activate the apelin receptor and are blocked by apelin receptor antagonists. This review summarizes the pharmacology of these ligands and the apelin receptor, highlights the emerging physiologic and pathophysiological roles in a number of diseases, and recommends that Elabela/Toddler is a second endogenous peptide ligand of the apelin receptor protein.

Apelin Reduces Nitric Oxide-Induced Relaxation of Cerebral Arteries by Inhibiting Activation of Large-Conductance, Calcium-Activated K Channels

Activation of the apelin/APJ receptor signaling system causes endothelium-dependent and nitric oxide (NO)-dependent relaxation in several peripheral arteries. The effects of apelin in cerebral arteries are unknown; however, apelin inhibits voltage-dependent increases in large-conductance, calcium-activated K channel (BKCa) currents in cerebral artery smooth muscle cells. Because NO-induced relaxation of cerebral arteries is mediated, in part, by activation of BKCa channels, the goals of this study were to determine the net effect of apelin in cerebral arteries, as well as test the hypothesis that the actions of apelin in cerebral arteries are secondary to stimulation of APJ receptors. Immunoblot and quantitative reverse transcription polymerase chain reaction analyses detected APJ receptors in cerebral arteries of male Sprague-Dawley rats, and immunofluorescence studies using confocal microscopy confirmed APJ receptor localization in smooth muscle cells. In myograph studies, apelin itself had no direct vasomotor effect but inhibited relaxations to the NO-donor, diethylamine NONOate, and to the endothelium-dependent vasodilator, bradykinin. These effects of apelin were mimicked by the selective BKCa-channel blocker, iberiotoxin, and suppressed by the APJ receptor antagonist, F13A. Apelin also inhibited relaxations evoked by the BKCa-channel openers, NS1619 and BMS 191011, but had no effect on relaxation to levcromakalim, a selective KATP-channel opener. Apelin had no effect on diethylamine NONOate-induced or bradykinin-induced increases in cyclic guanosine monophosphate levels. Patch clamp recordings demonstrated that apelin and iberiotoxin each suppressed the increase in BKCa currents induced by DEA and NS1619 in freshly isolated cerebral artery smooth muscle cells. The results demonstrate that apelin inhibits NO-induced relaxation of cerebral arteries through a mechanism involving activation of APJ receptors and inhibition of BKCa channels in cerebral arterial smooth muscle cells.

Detection of functional polymorphisms in the hsp70 gene and association with cold stress response in Inner-Mongolia Sanhe cattle

The genetic mechanisms underlying the cattle resilience to severe cold temperatures are still unknown. In this study, we observed that four blood biochemical parameters were significantly altered, i.e., blood adrenocorticotropic hormone (ACTH), triiodothyronine (T3), thyroxine (T4), and potassium (K+) after expose to - 32 °C for 3 h. This was observed using 105 healthy Sanhe heifers with similar weight (398.17 ± 34.06 kg) and age (19.30 ± 4.91 months). A total of 20 single nucleotide polymorphisms (SNPs) were identified in 5'-flanking region of the hsp70 gene in Sanhe cattle, while only 10 SNPs were segregating when comparing genetic variations between Sanhe cattle and 285 Chinese Holstein samples. Statistically significant associations between the genomic markers SNP-42-, SNP-105+, SNP-181+, and SNP-205+ with blood T3 and between SNP-105+ and blood T4 were observed by applying the general linear model procedure and Bonferroni t test. Furthermore, we demonstrated that the T alleles of SNP-42- and SNP-205+ in the GC box and Kozak sequence of the hsp70 gene, respectively, significantly decreased the green fluorescent proteins activity in vitro GFP reporter assays. These findings suggest that these two SNPs are causative polymorphisms involved in the regulation of hsp70 promoter activity and might contribute to the observed association between the hsp70 gene and T3 and T4 levels in Sanhe cattle. Thus, hsp70 gene is a promising candidate gene to be validated in independent cattle populations and functional studies related to cold stress resilience in cattle.

miR-129-2-3p directly targets SYK gene and associates with the risk of ischaemic stroke in a Chinese population

Spleen tyrosine kinase (SYK) gene has been identified as novel susceptibility locus for ischaemic stroke (IS) previously. However, regulation of SYK gene remains unknown in IS. In this study, we aimed to identify miRNAs that might be involved in the development of IS by targeting SYK gene. miRNAs were firstly screened by bioinformatics predicting tool. The expression levels of SYK gene were detected by qRT-PCR and western blotting, respectively, after miRNA transfection. Luciferase reporter assay was applied to investigate the direct binding between miRNAs and target gene. miRNA levels were detected by miRNA TaqMan assays in the blood cells of 270 IS patients and 270 control volunteers. Results suggest that SYK gene might be a direct target of miR-129-2-3p. The blood level of miR-129-2-3p was significantly lower in IS patients (P < 0.05), and negatively associated with the risk of IS (adjusted OR: 0.88; 95% CI: 0.80-0.98; P = 0.021) by multivariable logistic regression analysis. The blood levels of SYK gene were significantly higher in IS patients, and miR-129-2-3p expression was negatively correlated with mean platelet volume. In summary, our study suggests that miR-129-2-3p might be involved in the pathogenesis of IS through interrupting SYK expression and the platelet function, and further investigation is needed to explore the underlying mechanism.

Lack of association between the APLNR variant rs9943582 with ischemic stroke in the Chinese Han GeneID population

Stroke is one of the most common causes of death worldwide. Genetic risk factors have been found to play important roles in the pathology of ischemic stroke. In a previous genome-wide association study, a functional variant (rs9943582, –154G/A) in the 5’ flanking region of the apelin receptor gene (APLNR) was shown to be significantly associated with stroke in the Japanese population. However, the association required validation in other ethnicities. To validate the genetic relationship between APLNR and ischemic stroke in the Chinese Han population, we genotyped rs9943582 in a case–control population containing 1,158 ischemic stroke patients and 1,265 common controls enrolled from the GeneID database, and performed a genetic association study. We detected no allelic or genotypic associations between rs9943582 and ischemic stroke in the Chinese Han GeneID population, although the study population provided sufficient statistical power. This finding indicates that the association between the APLNR variant and ischemic stroke or atherosclerosis may need further validation.

Identification of six polymorphisms as novel susceptibility loci for ischemic or hemorrhagic stroke by exome-wide association studies

In this study, we performed exome-wide association studies (EWASs) to identify genetic variants that confer susceptibility to ischemic stroke, intracerebral hemorrhage (ICH), or subarachnoid hemorrhage (SAH). EWAS for ischemic stroke was performed using 1,575 patients with this condition and 9,210 controls, and EWASs for ICH and SAH were performed using 673 patients with ICH, 265 patients with SAH and 9,158 controls. Analyses were performed with Illumina HumanExome-12 DNA Analysis BeadChip or Infinium Exome-24 BeadChip arrays. The relation of allele frequencies for 41,339 or 41,332 single nucleotide polymorphisms (SNPs) that passed quality control to ischemic or hemorrhagic stroke, respectively, was examined with Fisher's exact test. Based on Bonferroni's correction, a P-value of <1.21x10-6 was considered statistically significant. EWAS for ischemic stroke revealed that 77 SNPs were significantly associated with this condition. Multivariable logistic regression analysis with adjustment for age, sex and the prevalence of hypertension and diabetes mellitus revealed that 4 of these SNPs [rs3212335 of GABRB3 (P=0.0036; odds ratio, 1.29), rs147783135 of TMPRSS7 (P=0.0024; odds ratio, 0.37), rs2292661 of PDIA5 (P=0.0054; odds ratio, 0.35) and rs191885206 of CYP4F12 (P=0.0082; odds ratio, 2.60)] were related (P<0.01) to ischemic stroke. EWASs for ICH or SAH revealed that 48 and 12 SNPs, respectively, were significantly associated with these conditions. Multivariable logistic regression analysis with adjustment for age, sex and the prevalence of hypertension revealed that rs138533962 of STYK1 (P<1.0x10-23; odds ratio, 111.3) was significantly (P<2.60x10-4) associated with ICH and that rs117564807 of COL17A1 (P=0.0009; odds ratio, 2.23x10-8) was significantly (P<0.0010) associated with SAH. GABRB3, TMPRSS7, PDIA5 and CYP4F12 may thus be novel susceptibility loci for ischemic stroke, whereas STYK1 and COL17A1 may be such loci for ICH and SAH, respectively.

The Role of the Apelin/APJ System in the Regulation of Liver Disease

Apelin is an endogenous peptide that is a ligand for the APJ receptor (angiotensin II receptor like-1, AT-1). The apelin/APJ system is distributed in diverse periphery organ tissues. It has been shown that the apelin/APJ system plays various roles in physiology and pathophysiology of many organs. It regulates cardiovascular development or cardiac disease, glycometabolism and fat metabolism as well as metabolic disease. The apelin/APJ system participates in various cell activities such as proliferation, migration, apoptosis or inflammation. However, apelin/APJ function in the liver is still under investigation. In the liver, the apelin-APJ system could play an inhibitory role in liver regeneration and promote Fas-induced apoptosis. It may participate in the formation of hepatic fibrosis or cirrhosis, and even cancer. In this review, we summarize the role of the apelin/APJ system in liver disease.

Temporal Expression of Apelin/Apelin Receptor in Ischemic Stroke and its Therapeutic Potential

Stroke is one of the leading causes of death and disability worldwide, and ischemic stroke accounts for approximately 87% of cases. Improving post-stroke recovery is a major challenge in stroke treatment. Accumulated evidence indicates that the apelinergic system, consisting of apelin and apelin receptor (APLNR), is temporally dysregulated in ischemic stroke. Moreover, the apelinergic system plays a pivotal role in post-stroke recovery by inhibiting neuronal apoptosis and facilitating angiogenesis through various molecular pathways. In this review article, we summarize the temporal expression of apelin and APLNR in ischemic stroke and the mechanisms of their dysregulation. In addition, the protective role of the apelinergic system in ischemic stroke and the underlying mechanisms of its protective effects are discussed. Furthermore, critical issues in activating the apelinergic system as a potential therapy will also be discussed. The aim of this review article is to shed light on exploiting the activation of the apelinergic system to treat ischemic stroke.

A Polymorphism Within the 3'UTR of NLRP3 is Associated with Susceptibility for Ischemic Stroke in Chinese Population

Stroke was regarded as a severe disorder with high morbidity and high mortality worldwide, ischemic stroke (IS) accounts for 85 to 90 % of new increased stroke cases. Partial mechanisms were elucidated by genetic factors including genomic instability such as single nucleotide polymorphism (SNP). Previous reports demonstrated that inflammation was involved in IS, NLRP3 [nucleotide-binding domain (NOD)-like receptor protein 3], acting as a specific inflammatory gene, however, its function and influence on IS was not well clarified. In this study, a case-control study including 1102 IS patients and 1610 healthy controls was conducted to investigate the association between IS susceptibility with a SNP (rs10754558) in 3'UTR of NLRP3. Logistic regression analysis showed that the heterozygote and the homozygote GG confer a significantly increased risk of CRC after controlling for other covariates (adjusted OR = 1.52, 95 % C.I. 1.19-1.97, P = 0.002; adjusted OR = 2.22, 95 % C.I. 2.18-3.67, P < 0.001, respectively). Carriage of G allele was associated with a greatly increased risk of developing the disease (OR = 1.69, 95 % C.I. 1.31-1.83, P < 0.001). Stratification analysis found that hypertension had interaction with rs10754558 to modulate IS risk. Further in vitro assay revealed that rs10754558 can affect mRNA level of NLRP3, suggesting its possible functional significance. Our data suggested that genetic polymorphisms in NLRP3 may influence IS risk in Chinese population. Replication of our studies in other populations and further functional studies are required for complete comprehension of the roles of NLRP3 polymorphisms in IS risk.

Lactation Is a Risk Factor of Postpartum Heart Failure in Mice with Cardiomyocyte-specific Apelin Receptor (APJ) Overexpression

The G protein-coupled receptor APJ and its ligand apelin are highly expressed in cardiovascular tissues and are associated with the regulation of blood pressure and cardiac function. Although accumulating evidence suggests that APJ plays a crucial role in the heart, it remains unclear whether up-regulation of APJ affects cardiac function. Here we generated cardiomyocyte-specific APJ-overexpressing (APJ-TG) mice and investigated the cardiac phenotype in APJ-TG mice. Male and non-pregnant APJ-TG mice showed cardiac hypertrophy, contractile dysfunction, and elevation of B-type natriuretic peptide gene expression in the heart but not cardiac fibrosis and symptoms of heart failure, including breathing abnormality and pleural effusion. We further examined the influence of APJ overexpression in response to physiological stress induced by pregnancy and lactation in the heart. Interestingly, repeating pregnancy and lactation (pregnancy-lactation cycle) exacerbated cardiac hypertrophy and systolic dysfunction and induced cardiac fibrosis, lung congestion, pleural effusion, and abnormal breathing in APJ-TG mice. These data indicate that female APJ-TG mice develop postpartum cardiomyopathy. We showed that lactation, but not parturition, was critical for the onset of postpartum cardiomyopathy in APJ-TG mice. Furthermore, we found that lactating APJ-TG mice showed impaired myocardial angiogenesis and imbalance of pro- and antiangiogenic gene expression in the heart. These results demonstrate that overexpression of APJ in cardiomyocytes has adverse effects on cardiac function in male and non-pregnant mice and that lactation contributes to the development of postpartum cardiomyopathy in the heart with APJ overexpression.

Genetic Determination of Serum Levels of Diabetes-Associated Adipokines

Adipose tissue secretes an abundance of proteins. Some of these proteins are known as adipokines and adipose-derived hormones which have been linked with metabolic disorders, including type 2 diabetes, and even with cancer. Variance in serum adipokine concentration is often closely associated with an increase (obesity) or decrease (lipodystrophy) in fat tissue mass, and it is affected by age, gender, and localization of the adipose tissue. However, there may be genetic variants which, in consequence, influence the serum concentration of a certain adipokine, and thereby promote metabolic disturbances or, with regard to the "protective" allele, exert beneficial effects. This review focuses on the genetic determination of serum levels of the following adipokines: adiponectin, chemerin, leptin, progranulin, resistin, retinol binding protein 4, vaspin, adipsin, apelin, and omentin. The article reports on the latest findings from genome-wide association studies (GWAS) and candidate gene studies, showing variants located in/nearby the adipokine genes and other (non-receptor) genes. An extra chapter highlights adipokine-receptor variants. Epigenetic studies on adipokines are also addressed.

Association of SNP Rs9943582 in APLNR with Left Ventricle Systolic Dysfunction in Patients with Coronary Artery Disease in a Chinese Han GeneID Population

Heart failure affects 1–2% of the adult population worldwide and coronary artery disease (CAD) is the underlying etiology of heart failure in 70% of the patients. The pathway of apelin and its apelin receptor (APJ) was implicated in the pathogenesis of heart failure in animal models, but a similar role in humans is unknown. We studied a functional variant, rs9943582 (-154G/A), at the 5’-untranslated region, that was associated with decreased expression of the APJ receptor gene (APLNR) in a population consisting of 1,751 CAD cases and 1,022 controls. Variant rs9943582 was not associated with CAD, but among CAD patients, it showed significant association with left ventricular systolic dysfunction (431 CAD patients with left ventricular systolic dysfunction (LV ejection fraction or LVEF< 40%) versus 1,046 CAD patients without LV systolic dysfunction (LVEF>50%) (P-adj = 6.71×10^-5, OR = 1.43, 95% CI, 1.20–1.70). Moreover, rs9943582 also showed significant association with quantitative echocardiographic parameters, including left ventricular end-diastolic diameter (effect size: increased 1.67±0.43 mm per risk allele A, P = 1.15×10^-4), left atrial size (effect size: increased 2.12±0.61 mm per risk allele A, P = 9.56×10^-4) and LVEF (effect size: decreased 2.59±0.32 percent per risk allele A, P = 7.50×10^-15). Our findings demonstrate that allele A of rs9943582 was significantly associated with left ventricular systolic dysfunction, left ventricular end-diastolic diameter, the left atrial diameter and LVEF in the CAD population, which suggests an important role of the apelin/APJ system in the pathology of heart failure associated with ischemic heart disease.

Association of CVD candidate gene polymorphisms with ischemic stroke and cerebral hemorrhage in Chinese individuals

BACKGROUND

Contribution of cardiovascular disease related genetic risk factors for stroke are not clearly defined. We performed a genetic association study to assess the association of 56 previously characterized gene variants in 34 candidate genes from cardiovascular disease related biological pathways with ischemic stroke and cerebral hemorrhage in a Chinese population.

METHODS

There were 1280 stroke patients (1101 with ischemic stroke and 179 with cerebral hemorrhage) and 1380 controls in the study. The genotypes for 56 polymorphisms of 34 candidate genes were determined by the immobilized probe approach and the associations of gene polymorphisms with ischemic stroke and cerebral hemorrhage were performed by logistic regression under an allelic model.

RESULTS

After adjusting for age, sex, BMI and hypertension status by logistic regression analysis, we found that NPPA rs5063 was significantly associated with both ischemic stroke (odds ratio [OR] 0.69; 95% confidence interval [CI], 0.52 to 0.90; P = 0.006) and cerebral hemorrhage(OR = 0.39; 95%CI, 0.19 to 0.78; P = 0.007). In addition, MTHFR rs1801133 also was associated with cerebral hemorrhage (OR = 1.48; 95%CI, 1.16 to 1.89; P = 0.001) but not with ischemic stroke (OR = 1.08; 95%CI, 0.96 to 1.22; P = 0.210). After false discovery rate (FDR) correction, the association of NPPA rs5063 and MTHFR rs1801133 with cerebral hemorrhage remained significant.

CONCLUSIONS

The NPPA rs5063 is associated with reduced risk for cerebral hemorrhage and MTHFR rs1801133 is associated with increased risk of cerebral hemorrhage in a Chinese population.

SNP@lincTFBS: an integrated database of polymorphisms in human LincRNA transcription factor binding sites

Large intergenic non-coding RNAs (lincRNAs) are a new class of functional transcripts, and aberrant expression of lincRNAs was associated with several human diseases. The genetic variants in lincRNA transcription factor binding sites (TFBSs) can change lincRNA expression, thereby affecting the susceptibility to human diseases. To identify and annotate these functional candidates, we have developed a database SNP@lincTFBS, which is devoted to the exploration and annotation of single nucleotide polymorphisms (SNPs) in potential TFBSs of human lincRNAs. We identified 6,665 SNPs in 6,614 conserved TFBSs of 2,423 human lincRNAs. In addition, with ChIPSeq dataset, we identified 139,576 SNPs in 304,517 transcription factor peaks of 4,813 lincRNAs. We also performed comprehensive annotation for these SNPs using 1000 Genomes Project datasets across 11 populations. Moreover, one of the distinctive features of SNP@lincTFBS is the collection of disease-associated SNPs in the lincRNA TFBSs and SNPs in the TFBSs of disease-associated lincRNAs. The web interface enables both flexible data searches and downloads. Quick search can be query of lincRNA name, SNP identifier, or transcription factor name. SNP@lincTFBS provides significant advances in identification of disease-associated lincRNA variants and improved convenience to interpret the discrepant expression of lincRNAs. The SNP@lincTFBS database is available at http://bioinfo.hrbmu.edu.cn/SNP_lincTFBS.

Genetics of ischaemic stroke

Recent advances in genomics and statistical computation have allowed us to begin addressing the genetic basis of stroke at a molecular level. These advances are at the cusp of making important changes to clinical practice of some monogenic forms of stroke and, in the future, are likely to revolutionise the care provided to these patients. In this review we summarise the state of knowledge in ischaemic stroke genetics particularly in the context of how a practicing clinician can best use this knowledge.

Two novel susceptibility SNPs for ischemic stroke using exome sequencing in Chinese Han population

Genome-wide association studies (GWAS) of ischemic stroke (IS) have been performed on several cohorts of Caucasian or African population and Japanese, resulting in somewhat inconsistent conclusion. We aimed to identify susceptibility loci for IS by exome sequencing in a Chinese Han population. Exome sequencing was used to screen susceptibility loci among 100 cases and 100 matched controls. Significant SNPs from the first stage were verified in up to 3,554 participants from three hospital-based case-control studies. In the initial exome sequencing analysis, rs10489177 in c1orf156 gene located on chromosome 1q24 (p < 1 × 10(-8)) and rs17118 in XYLB gene located on chromosome 3p21 (p < 1 × 10(-6)) were found to be significantly associated with IS. In the following validation stage, significantly increased odds ratios were observed in individuals with rs10489177 GG (OR = 2.02, 95 % CI = 1.35-3.03) or rs17118 AA genotype (OR = 1.50, 95 % CI = 1.17-1.91). The rs10489177 GG genotype was associated with significantly increased risk for IS in individuals without hypertension (OR = 2.78, 95 % CI = 1.59-4.86) and in individuals without diabetes (OR = 1.93, 95 % CI = 1.27-2.94). In contrast, the rs17118 AA genotype may significantly increase the risk for IS, particularly for individuals with hypertension (OR = 1.73, 95 % CI = 1.08-2.78) and for individuals without diabetes (OR = 1.52, 95 % CI = 1.17-1.98) or non-smoker (OR = 1.59, 95 % CI = 1.16-2.19). Collectively, our study identified two novel loci (rs17118 and rs10489177) which were associated with an increased risk for IS in Chinese Han populations. Further studies are needed to confirm these associations in other populations and elucidate the biological mechanisms underlying the observed associations.

The apelin receptor APJ: journey from an orphan to a multifaceted regulator of homeostasis

The apelin receptor (APJ; gene symbol APLNR) is a member of the G protein-coupled receptor gene family. Neural gene expression patterns of APJ, and its cognate ligand apelin, in the brain implicate the apelinergic system in the regulation of a number of physiological processes. APJ and apelin are highly expressed in the hypothalamo-neurohypophysial system, which regulates fluid homeostasis, in the hypothalamic-pituitary-adrenal axis, which controls the neuroendocrine response to stress, and in the forebrain and lower brainstem regions, which are involved in cardiovascular function. Recently, apelin, synthesised and secreted by adipocytes, has been described as a beneficial adipokine related to obesity, and there is growing awareness of a potential role for apelin and APJ in glucose and energy metabolism. In this review we provide a comprehensive overview of the structure, expression pattern and regulation of apelin and its receptor, as well as the main second messengers and signalling proteins activated by apelin. We also highlight the physiological and pathological roles that support this system as a novel therapeutic target for pharmacological intervention in treating conditions related to altered water balance, stress-induced disorders such as anxiety and depression, and cardiovascular and metabolic disorders.

Identification of a functional variant in the MICA promoter which regulates MICA expression and increases HCV-related hepatocellular carcinoma risk

Hepatitis C virus (HCV) infection is the major cause of hepatocellular carcinoma (HCC) in Japan. We previously identified the association of SNP rs2596542 in the 5' flanking region of the MHC class I polypeptide-related sequence A (MICA) gene with the risk of HCV-induced HCC. In the current study, we performed detailed functional analysis of 12 candidate SNPs in the promoter region and found that a SNP rs2596538 located at 2.8 kb upstream of the MICA gene affected the binding of a nuclear protein(s) to the genomic segment including this SNP. By electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay, we identified that transcription factor Specificity Protein 1 (SP1) can bind to the protective G allele, but not to the risk A allele. In addition, reporter construct containing the G allele was found to exhibit higher transcriptional activity than that containing the A allele. Moreover, SNP rs2596538 showed stronger association with HCV-induced HCC (P = 1.82 × 10(-5) and OR = 1.34) than the previously identified SNP rs2596542. We also found significantly higher serum level of soluble MICA (sMICA) in HCV-induced HCC patients carrying the G allele than those carrying the A allele (P = 0.00616). In summary, we have identified a functional SNP that is associated with the expression of MICA and the risk for HCV-induced HCC.

Interactive association of five candidate polymorphisms in Apelin/APJ pathway with coronary artery disease among Chinese hypertensive patients

Background

Via sequencing the genes of apelin/angiotensin receptor-like 1 (apelin/APJ) pathway, we have recently identified and validated four common polymorphisms (rs3761581, rs56204867, rs7119375, and rs10501367) implicated in the development of hypertension. Extending these findings, we, in Chinese hypertensive patients, sought to investigate the association of these four polymorphisms and one additional promising candidate (rs9943582) from this pathway with the risk of developing coronary artery disease (CAD).

Methodology/Principal Findings

Genotypes were obtained from 994 sporadic CAD patients and 708 age- and sex-matched controls. All participants were hypertensives and angiographically-confirmed. Data were analyzed by Haplo.Stats and multifactor dimensionality reduction (MDR) softwares. Genotype distributions of five examined polymorphisms satisfied Hardy-Weinberg equilibrium in controls of both genders. Single-locus analyses exhibited no significant differences in the genotype/allele frequencies of examined polymorphisms between CAD patients and controls (P>0.05), even after controlling traditional cardiovascular confounders. In haplotype analyses, low-penetrance haplotype G-A (in order of rs56204867 and rs3761581 from apelin gene) was significantly overrepresented in controls (1.73%) relative to in CAD patients (0.4%) in males (P = 0.047). Further interaction analyses suggested an overall best MDR model including rs3761581 in males (P = 0.0408) and including rs7119375 and rs9943582 in females (P<0.0001), which were further substantiated in the classical logistical regression model.

Conclusions

Our findings demonstrated a contributive role of low-penetrance haplotype in apelin gene on CAD in males, and more importantly, interactive effects of genetic defects in apelin/APJ pathway might confer a potential risk in Chinese hypertensive patients.

Soluble MICA and a MICA variation as possible prognostic biomarkers for HBV-induced hepatocellular carcinoma

MHC class I polypeptide-related chain A (MICA) molecule is induced in response to viral infection and various types of stress. We recently reported that a single nucleotide polymorphism (SNP) rs2596542 located in the MICA promoter region was significantly associated with the risk for hepatitis C virus (HCV)-induced hepatocellular carcinoma (HCC) and also with serum levels of soluble MICA (sMICA). In this study, we focused on the possible involvement of MICA in liver carcinogenesis related to hepatitis B virus (HBV) infection and examined correlation between the MICA polymorphism and the serum sMICA levels in HBV-induced HCC patients. The genetic association analysis revealed a nominal association with an SNP rs2596542; a G allele was considered to increase the risk of HBV-induced HCC (P = 0.029 with odds ratio of 1.19). We also found a significant elevation of sMICA in HBV-induced HCC cases. Moreover, a G allele of SNP rs2596542 was significantly associated with increased sMICA levels (P = 0.009). Interestingly, HCC patients with the high serum level of sMICA (>5 pg/ml) exhibited poorer prognosis than those with the low serum level of sMICA (≤5 pg/ml) (P = 0.008). Thus, our results highlight the importance of MICA genetic variations and the significance of sMICA as a predictive biomarker for HBV-induced HCC.

Exploring the interaction between SNP genotype and postmenopausal hormone therapy effects on stroke risk

BACKGROUND

Genome-wide association studies have identified several genomic regions that are associated with stroke risk, but these provide an explanation for only a small fraction of familial stroke aggregation. Genotype by environment interactions may contribute further to such an explanation. The Women's Health Initiative (WHI) clinical trial found increased stroke risk with postmenopausal hormone therapy (HT) and provides an efficient setting for evaluating genotype-HT interaction on stroke risk.

METHODS

We examined HT by genotype interactions for 392 SNPs selected from candidate gene studies, and 2,371 SNPs associated with changes in blood protein concentrations after hormone therapy, in analyses that included 2,045 postmenopausal women who developed stroke during WHI clinical trial and observational study follow-up and one-to-one matched controls. A two-stage procedure was implemented where SNPs passing the first stage screening based on marginal association with stroke risk were tested in the second stage for interaction with HT using case-only analysis.

RESULTS

The two-stage procedure identified two SNPs, rs2154299 and rs12194855, in the coagulation factor XIII subunit A (F13A1) region and two SNPs, rs630431 and rs560892, in the proprotein convertase subtilisin kexin 9 (PCSK9) region, with an estimated false discovery rate <0.05 based on interaction tests. Further analyses showed significant stroke risk interaction between these F13A1 SNPs and estrogen plus progestin (E+P) treatment for ischemic stroke and for ischemic and hemorrhagic stroke combined, and suggested interactions between PCSK9 SNPs with either E+P or estrogen-alone treatment.

CONCLUSIONS

Genotype by environment interaction information may help to define genomic regions relevant to stroke risk. Two-stage analysis among postmenopausal women generates novel hypotheses concerning the F13A1 and PCSK9 genomic regions and the effects of hormonal exposures on postmenopausal stroke risk for subsequent independent validation.

Biology of the apelin-APJ axis in vascular formation

Apelin is a bioactive peptide with diverse physiological actions on many tissues mediated by its interaction with its specific receptor APJ. Since the identification of apelin and APJ in 1998, pleiotropic roles of the apelin/APJ system have been elucidated in different tissues and organs, including modulation of the cardiovascular system, fluid homeostasis, metabolic pathway and vascular formation. In blood vessels, apelin and APJ expression are spatiotemporally regulated in endothelial cells (ECs) during angiogenesis. In vitro analysis revealed that the apelin/APJ system regulates angiogenesis by the induction of proliferation, migration and cord formation of cultured ECs. Moreover, apelin seems to stabilize cell-cell junctions of ECs. In addition, genetically engineered mouse models suggest that apelin/APJ regulates vascular stabilization and maturation in physiological and pathological angiogenesis. In this review, we summarize the current understanding of the apelin/APJ system for vascular formation and maturation.

Renin-Angiotensin system hyperactivation can induce inflammation and retinal neural dysfunction

The renin-angiotensin system (RAS) is a hormone system that has been classically known as a blood pressure regulator but is becoming well recognized as a proinflammatory mediator. In many diverse tissues, RAS pathway elements are also produced intrinsically, making it possible for tissues to respond more dynamically to systemic or local cues. While RAS is important for controlling normal inflammatory responses, hyperactivation of the pathway can cause neural dysfunction by inducing accelerated degradation of some neuronal proteins such as synaptophysin and by activating pathological glial responses. Chronic inflammation and oxidative stress are risk factors for high incidence vision-threatening diseases such as diabetic retinopathy (DR), age-related macular degeneration (AMD), and glaucoma. In fact, increasing evidence suggests that RAS inhibition may actually prevent progression of various ocular diseases including uveitis, DR, AMD, and glaucoma. Therefore, RAS inhibition may be a promising therapeutic approach to fine-tune inflammatory responses and to prevent or treat certain ocular and neurodegenerative diseases.

Elevation of carcinoembryonic antigen coinciding with disease activity of ulcerative colitis

We report on three cases of ulcerative colitis who presented with increased levels of serum carcinoembryonic antigen (CEA) during the active stage. All cases were pancolitis with a moderate to severe disease course. After remission induction with medical therapies, serum CEA levels decreased to the normal reference range. Immunohistochemical analyses demonstrated the existence of CEA not only along with the apical surface of the colonic epithelia but also at the cytosol of the inflamed epithelia where goblet cells were depleted during the active stage. We speculate that CEA was up-regulated by inflammatory response particularly in the process of epithelial regeneration.

Apelin is required for non-neovascular remodeling in the retina

Retinal pathologies are frequently accompanied by retinal vascular responses, including the formation of new vessels by angiogenesis (neovascularization). Pathological vascular changes may also include less well characterized traits of vascular remodeling that are non-neovascular, such as vessel pruning and the emergence of dilated and tortuous vessel phenotypes (telangiectasis). The molecular mechanisms underlying neovascular growth versus non-neovascular remodeling are poorly understood. We therefore undertook to identify novel regulators of non-neovascular remodeling in the retina by using the dystrophic Royal College of Surgeons (RCS) rat and the retinal dystrophy 1 (RD1) mouse, both of which display pronounced non-neovascular remodeling. Gene expression profiling of isolated retinal vessels from these mutant rodent models and wild-type controls revealed 60 differentially expressed genes. These included the genes for apelin (Apln) and for its receptor (Aplnr), both of which were strongly up-regulated in the mutants. Crossing RD1 mice into an Apln-null background substantially reduced vascular telangiectasia. In contrast, Apln gene deletion had no effect in two models of neovascular pathology [laser-induced choroidal neovascularization and the very low density lipoprotein receptor (Vldlr)-knockout mouse]. These findings suggest that in these models apelin has minimal effect on sprouting retinal angiogenesis, but contributes significantly to pathogenic non-neovascular remodeling.

Apelin and insulin resistance: another arrow for the quiver?

Apelin is a newly discovered peptide hormone that has recently been linked to insulin resistance and obesity. Data collected from both the clinical and basic research settings show that apelin: (i) is correlated with the states of insulin resistance and obesity; (ii) stimulates glucose utilization; (iii) decreases insulin secretion; and (iv) negatively regulates catecholamine-mediated lipolysis. These and other lines of evidence demonstrate that apelin may be a potentially viable candidate in the search for treatments for Type 2 diabetes and the insulin resistance (metabolic syndrome). The present review summarizes the literature on the regulation by apelin of glucose and lipid metabolism and the signaling pathways involved.

Common variants in a novel gene, FONG on chromosome 2q33.1 confer risk of osteoporosis in Japanese

Osteoporosis is a common disease characterized by low bone mass, decreased bone quality and increased predisposition to fracture. Genetic factors have been implicated in its etiology; however, the specific genes related to susceptibility to osteoporosis are not entirely known. To detect susceptibility genes for osteoporosis, we conducted a genome-wide association study in Japanese using ∼270,000 SNPs in 1,747 subjects (190 cases and 1,557 controls) followed by multiple levels of replication of the association using a total of ∼5,000 subjects (2,092 cases and 3,114 controls). Through these staged association studies followed by resequencing and linkage disequilibrium mapping, we identified a single nucleotide polymorphism (SNP), rs7605378 associated with osteoporosis. (combined P = 1.51×10⁻⁸, odds ratio = 1.25). This SNP is in a previously unknown gene on chromosome 2q33.1, FONG. FONG is predicted to encode a 147 amino-acid protein with a formiminotransferase domain in its N-terminal (FTCD_N domain) and is ubiquitously expressed in various tissues including bone. Our findings would give a new insight into osteoporosis etiology and pathogenesis.

New information on the genetics of stroke

Ischemic stroke, white matter hyperintensities related to small vessel ischemia, and intracranial aneurysms all show heritability. This review focuses on recent progress in understanding the molecular genetics of these disorders. Also reviewed is recent progress in understanding single-gene disorders in which stroke is a major feature of the phenotype, including CADASIL, CARASIL, hereditary angiopathy with nephropathy, aneurysm and muscle cramps, and Fabry disease and progress in pharmacogenomics as it relates to response to antiplatelet therapy.

Genetic risk factors for stroke in the genome-wide association era

IMPORTANCE OF THE FIELD

Recent genome-wide association studies (GWASs) have renewed interest in genetic determinants of a wide range of complex traits and disorders, including stroke.

AREAS COVERED IN THIS REVIEW

This paper reviews the current knowledge of genes that contribute to rare monogenic forms of stroke as well as more common 'garden variety' forms, focusing on the results of GWASs. Potential clinical pharmacogenetic and diagnostic applications of this information are considered. Publications from 1990 to September 2010 were identified through a Medline search using terms 'human stroke' and 'genetics', 'monogenic', 'familial', 'mutation', 'genome-wide association study', 'polymorphism', or 'genotype'.

WHAT THE READER WILL GAIN

The review synthesizes and collates the current understanding of genes that are involved across a range of stroke subphenotypes.

TAKE HOME MESSAGE

The complexity of stroke will make translation of genetic findings into new diagnostic or therapeutic tools relatively more challenging than for some other conditions and tempers the authors' enthusiasm for the eventual clinical utility of this information.

[Genome-wide association study for ischemic stroke based on the Hisayama study]

Ischemic stroke is a major cause of death and disability, and occurs owing to a combination of multiple environmental and genetic risk factors. Although twin studies and family-based studies have suggested the existence of genetic risk factors for ischemic stroke, few candidate genes have been discovered. To identify genes for susceptibility to ischemic stroke, we performed a genome-wide association study using 52,608 single nucleotide polymorphism (SNP) markers. After comparison of allele frequencies between 1,112 patients with ischemic stroke and the same number of age- and sex-matched control subjects, who were selected from among the residents of the town of Hisayama, Japan, we identified three novel candidate genes for ischemic stroke: PRKCH (protein kinase C eta (PKCη)), AGTRL1 (apelin receptor), and ARHGEF10 (Rho guanine nucleotide exchange factor 10). In the functional analyses, we found that PKCη was expressed mainly in vascular endothelial cells and foamy macrophages in human atherosclerotic lesions, and that the kinase activity of PKCη was modified by a nonsynonymous SNP in PRKCH (rs2230500). We also clarified that functional SNPs in AGTRL1 (rs9943582) and ARHGEF10 (rs4376531) affected transcriptional activities owing to the different Sp1-binding affinities. In a 14-year follow-up cohort study of Hisayama residents, all of these SNPs were significantly associated with the development of ischemic stroke. Although the mechanisms of these genes in the pathogenesis of ischemic stroke are still to be elucidated, our findings might contribute to a better understanding of ischemic stroke in the future.

Genetic bases for glaucoma

Glaucoma is the leading cause of visual impairment and blindness throughout the world. Primary open angle glaucoma (POAG; MIM 137760) is the main type of glaucoma in most populations, and more than 20 genetic loci for POAG have been reported. Only three causative genes have been identified in these loci, viz. myocilin (MYOC), optineurin (OPTN), and WD repeat domain 36 (WDR36). However, mutations in these genes account for only a small percentage of the patients with POAG. Some of these glaucoma cases have a Mendelian inheritance pattern, and a considerable fraction of the cases result from a large number of variants in several genes each contributing small effects. Glaucoma is considered to be a common disease such as diabetes mellitus, coronary disease, Crohn disease, and several( )common cancers. The main technological approaches used to identify the genes associated with glaucoma are the candidate gene approach, linkage analysis, case-control association study, and genome-wide association study. Association studies have found about 27 genes related to POAG, but the glaucoma-causing effects of these genes need to be investigated in more detail. The current trend is to use case-control association studies or genome-wide association studies to map the genes associated with glaucoma. Such studies are expected to greatly advance our understanding of the genetic basis of glaucoma, and to provide information on the effectiveness of glaucoma therapy. This review gives an overview on the genetic aspects of glaucoma.

Hip geometry variation is associated with bone mineralization pathway gene variants: The Framingham Study

Mineralization of bone matrix is an important process in bone formation; thus defects in mineralization have been implicated in bone mineral density (BMD) and bone structure alterations. Three central regulators of phosphate balance, ALPL, ANKH, and ENPP1, are central in the matrix mineralization process; therefore, the genes encoding them are considered important candidates genes for BMD and bone geometry. To test for an association between these three candidate genes and BMD and bone geometry traits, 124 informative singlenucleotide polymorphisms (SNPs) were selected and genotyped in 1513 unrelated subjects from the Framingham offspring cohort. Initial results showed that SNP rs1974201 in the gene ENPP1 was a susceptibility variant associated with several hip geometric indices, with the strongest p value of 3.8 × 10(7) being observed for femoral neck width. A few modest associations were observed between SNPs in or near ALPL and several bone traits, but no association was observed with ANKH. The association signals observed for SNPs around rs1974201 were attenuated after conditional analysis on rs1974201. Transcription factor binding-site prediction revealed that the HOXA7 binding site was present in the reference sequence with the major allele, whereas this potential binding site is lost in the sequence with the minor allele of rs1974201. In conclusion, we found evidence for association of bone geometry variation with an SNP in ENPP1, a gene in the mineralization pathway. The alteration of a binding site of the deregulator of extracellular matrix HOXA7 warrants further investigation.