Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Age-related macular degeneration (AMD) is a genetically heterogeneous disease that leads to progressive and irreversible vision loss among the elderly. Inflammation, oxidative damage, cholesterol metabolism and/or impaired function of retinal pigment epithelium (RPE) have been implicated in AMD pathogenesis. We examined toll-like receptor 4 (TLR4) as a candidate gene for AMD susceptibility because: (i) the TLR4 gene is located on chromosome 9q32-33, a region exhibiting evidence of linkage to AMD in three independent reports; (ii) the TLR4-D299G variant is associated with reduced risk of atherosclerosis, a chronic inflammatory disease with subendothelial accumulation; (iii) the TLR4 is not only a key mediator of proinflammatory signaling pathways but also linked to regulation of cholesterol efflux and (iv) the TLR4 participates in phagocytosis of photoreceptor outer segments by the RPE. We examined D299G and T399I variants of TLR4 in a sample of 667 unrelated AMD patients and 439 unrelated controls, all of Caucasian ancestry. Multiple logistic regression demonstrated an increased risk of AMD in carriers of the G allele at TLR4 residue 299 (odds ratio=2.65, P=0.025), but lack of an independent effect by T399I variant. TLR4-D299G showed an additive effect on AMD risk (odds ratio=4.13, P=0.002) with allelic variants of apolipoprotein E (APOE) and ATP-binding cassette transporter-1 (ABCA1), two genes involved in cholesterol efflux. Interestingly, the effect of TLR4, APOE and ABCA1 variants on AMD susceptibility was opposite to that of association with atherosclerosis risk. Our data provide evidence of a link between multiple diverse mechanisms underlying AMD pathogenesis.
Hum Mol Genet 2005 Jun 01
PMID:Toll-like receptor 4 variant D299G is associated with susceptibility to age-related macular degeneration. 1582 98

Abnormal activation of CXCR 4 during inflammatory/infectious states may lead to neuronal dysfunction or damage. The major goal of this study was to determine the coupling of CXCR 4 to p53-dependent survival pathways in primary neurons. Neurons were stimulated with the HIV envelope protein gp120(IIIB) or the endogenous CXCR 4 agonist, SDF-1 alpha. We found that gp120 stimulates p53 activity and induces expression of the p53 pro-apoptotic target Apaf-1 in cultured neurons. Inhibition of CXCR 4 by AMD 3100 abrogates the effect of gp120 on both p53 and Apaf-1. Moreover, gp120 neurotoxicity is markedly reduced by the p53-inhibitor, pifithrin-alpha. The viral protein also regulates p53 phosphorylation and expression of other p53-responsive genes, such as MDM 2 and p21. Conversely, SDF-1 alpha, which can promote neuronal survival, increases p53 acetylation and p21 expression in neurons. Thus, the stimulation of different p53 targets could be instrumental in determining the outcome of CXCR 4 activation on neuronal survival in neuro-inflammatory disorders.
Mol Cell Neurosci 2005 Sep
PMID:Regulation of neuronal P53 activity by CXCR 4. 1600 38

Signaling pathways that upregulate melanization in the retinal pigment epithelium (RPE) may also be implicated in the downregulation of rod outer segment (ROS) phagocytosis by the RPE. Melanization activating pathways may also modulate oxygen consumption by the photoreceptors, apolipoprotein E4 levels, and the rate of photoisomerization events such that the net effect may be a reduction in drusen and/or lipofuscin accumulation. An increase in melanin at the apical microvilli of the RPE may shield ROS from light thereby contributing in part to the decrease in the rate of ROS phagocytosis. This decrease in ROS phagocytosis by the RPE may serve to maintain a balance between ingestion and degradation/recycling thereby avoiding an increase to its already substantial metabolic load. Several experimental drugs for age related macular degeneration (ARMD) coincidentally are also capable of decreasing the rate of ROS phagocytosis. This review attempts to identify the signaling pathways that may link the upregulation of melanization to the downregulation of ROS phagocytosis. Phagocytic pathways that are modulated by melanization need to be studied in isolation to determine what role, if any, they possess in ameliorating the onset and progression of ARMD. Many more empirical studies are needed to unravel specific pathways and mechanisms that seem to link melanization with ARMD.
Mol Vis 2005 Jul 07
PMID:Melanization and phagocytosis: implications for age related macular degeneration. 1603 Apr 99

Age-related macular degeneration (AMD) is a multifactorial disease and a prevalent cause of visual impairment in developed countries. Risk factors include environmental components and genetic determinants. The complement factor H (CFH) has been the first major susceptibility gene for AMD identified within 1q32. Here, we focused on a second region of interest in 10q26 where a recent meta-analysis revealed strongest evidence for linkage to AMD at a genome-wide significance level. Within an interval of 22 Mb, we have analyzed 93 single nucleotide polymorphisms for allelic association with AMD in two independent case-control cohorts of German origin (AMD(combined) n=1166; controls(combined) n=945). Significant association was found across a 60 kb region of high linkage disequilibrium harboring two genes PLEKHA1 and hypothetical LOC387715. The strongest association (P=10(-34)) centered over a frequent coding polymorphism, Ala69Ser, at LOC387715, strongly implicating this gene in the pathogenesis of AMD. Besides abundant expression in placenta, we demonstrate weak expression of LOC387715 in the human retina. At present, however, there is no functional information on this gene, which appears to have evolved recently within the primate lineage. The joint contribution of the common risk allele at LOC387715, Ala69Ser, and at CFH, Tyr402His, was assessed in our case-control population, which suggests an additive model indicating an independent contribution of the two gene loci to disease risk. Our data show a disease odds ratio of 57.6 (95% CI: 37.2, 89.0) conferred by homozygosity for risk alleles at both CFH and LOC387715 when compared with the baseline non-risk genotype.
Hum Mol Genet 2005 Nov 01
PMID:Hypothetical LOC387715 is a second major susceptibility gene for age-related macular degeneration, contributing independently of complement factor H to disease risk. 1617 43

Identification of groups of co-regulated genes (regulons) is an important part of studying transcriptional regulation. One possible approach is to cluster regulatory sites that were found using experimental or computational techniques, such as phylogenetic footprinting. This strategy doesn't require a priori knowledge about co-regulation and allows finding putative new members of known groups of co-regulated genes (i.e. a new regulon). Also, it allows finding new putative regulons, which is especially important for poorly annotated genomes. We have developed ClusterTree-RS, an algorithm for clustering regulatory signals using binary trees; it is presented in this paper along with some testing results on simulated and real data. The algorithm is implemented in Java and took about 2 hours 40 minutes to cluster 1500 input signals on a computer with AMD Athlon 1.91 GHz CPU.
Mol Biol (Mosk)
PMID:[ClusterTree-RS: the binary tree algorithm for identification of co-regulated genes by clustering regulatory signals]. 1681 71

Age-related macular degeneration (AMD) is the leading cause of visual impairment and blindness among the elderly in Western countries. Genetic factors, age, cigarette smoking, nutrition, and exposure to light have been identified as AMD risk factors. In this study, we investigated the association between ApoE C112R/R158C single nucleotide polymorphisms (which determine the E2, E3, and E4 isoforms) and age-related macular degeneration (AMD), and the mechanism underlying the association. Genomic DNA was extracted from 133 clinically screened controls, 94 volunteers with a younger mean age, 120 patients with advanced AMD, and 40 archived ocular AMD slides for single nucleotide polymorphism typing. The effects of recombinant ApoE isoforms on CCL2 (a chemokine), CX3CR1 (a chemokine receptor), and VEGF (a cytokine) expression in cultured human retinal pigment epithelium (RPE) cells were tested and serum cholesterol profiles of the clinically screened subjects were analyzed. ApoE112R (E4) distribution differed significantly between AMD patients and controls. ApoE112R allele frequency was 10.9% in the AMD group when compared with 16.5% in the younger controls and 18.8% in the clinically screened controls. The pathologically diagnosed archived AMD cases had the lowest allele frequency of 5%. No significant differences in ApoE158C (E2) distribution were observed among the groups. A meta-analysis of 8 cohorts including 4,289 subjects showed a strong association between AMD and 112R, but not 158C. In vitro studies found that recombinant ApoE suppresses CCL2 and VEGF expression in RPE cells. However, the E4 isoform showed more suppression than E3 in both cases. These results further confirm the association between ApoE112R and a decreased risk of AMD development. The underlying mechanisms may involve differential regulation of both CCL2 and VEGF by the ApoE isoforms.
Environ Mol Mutagen 2006 Oct
PMID:An apolipoprotein E variant may protect against age-related macular degeneration through cytokine regulation. 1682 65

Age-related macular degeneration (AMD) is the leading cause of blindness in the developed world and complement factor H (CFH) polymorphism has been found to associated with the AMD. We performed a meta-analysis to estimate the magnitude of the gene effect and the possible mode of action. A meta-analysis of eight studies assessing association between the CFH Y402H polymorphism and AMD was performed. Data extraction and study quality assessment were performed in duplicate, and heterogeneity and publication bias were explored. There was strong evidence for association between CFH and AMD, with those having CC and TC genotypes being roughly six and 2.5 times more likely to have AMD than patients with TT genotype, suggesting a co-dominant, multiplicative genetic model. The population attributable risk for the CC/TC genotype is 58.9%, i.e. the CFH polymorphism is involved in over half of all AMD. This meta-analysis summarizes the strong evidence for an association between CFH and AMD and indicates a multiplicative model with each C allele increasing the odds of AMD by approximately 2.5-fold. This result is at least as important at the population level as ApoE4 and Alzheimer's disease, playing a role in almost 60% of AMD at the population level.
Hum Mol Genet 2006 Sep 15
PMID:Systematic review and meta-analysis of the association between complement factor H Y402H polymorphisms and age-related macular degeneration. 1690 58

Age-related macular degeneration (AMD) is the most common cause of blindness in the elderly. Linkage has been shown to the vascular endothelial growth factor (VEGF) gene and ocular levels of VEGF are raised in individuals with the neovascular form of disease. To examine the role of VEGF further, we conducted a case-control study where 45 individuals with neovascular AMD and 94 age-matched controls were genotyped for 14 single nucleotide polymorphisms (SNPs) in the VEGF promoter and gene. The single SNP +674 CC genotype was significantly associated with AMD (OR=2.40, 95%CI 1.09-5.26, P=0.027). Haplotype analysis of SNPs +674, +4618, +5092, +9162 and +9512 revealed that CTCCT and TCACC were associated with AMD (OR=15.77, 95% CI 1.91-130.24, P=0.0161 and OR=9.95, 95%CI 3.22-30.74, P=0.000053, respectively). The haplotype TCACT was associated with the control group (P=0.0001832). Furthermore, haplotype analysis of promoter SNPs revealed that possession of the -460T, -417T, -172C, -165C, -160C, -152G, -141A, -116A, +405C haplotype was strongly associated with AMD (OR=18.24, 95%CI 2.25-148.25, P=0.0074). This is the most extensive analysis of the VEGF gene in AMD, demonstrating a clear association with the exudative form of disease, thereby creating the possibility for predictive testing. Smoking, high fat intake and hypertension are negative environmental risk factors in AMD, whereas increased consumption of dietary antioxidants can have a protective effect. Identification of those at risk in the population would allow individual counselling with lifestyle advice to reduce the risks of blindness. (Genbank accession nos M63971 and AF437895).
Hum Mol Genet 2006 Oct 01
PMID:VEGF polymorphisms are associated with neovascular age-related macular degeneration. 1694 Mar 9

Age-related macular degeneration (AMD) is a genetically complex disorder of the photoreceptor-RPE-Bruch's membrane-choriocapillaris complex. Family and twin studies have shown that the susceptibility for this disease is genetically influenced. The heritability has been estimated to be up to 71%. Linkage and association studies have identified several chromosomal regions that are likely to contain susceptibility loci with strongest evidence found on chromosome 1q31 and 10q26. Variants in the complement factor H (CFH) gene have been shown by several independent studies to be associated with an increased risk for AMD in Caucasian populations. These findings imply that the innate immune system may play a significant role in AMD pathogenesis. The LOC387715/HTRA1 locus within 10q26 has been identified as a second major locus contributing to AMD pathogenesis. The two late forms of AMD, choroidal neovascularization and geographic atrophy, have not been found to be different in risk allele distribution. Variants within CFH and LOC387715/HTRA1 may contribute to the increased risk of late AMD largely through their impact on precursors, such as drusen and/or other RPE/Bruch's membrane changes. Considering variants at CFH, LOC387715/HTRA1 and complement component 2-complement factor B (C2-FB), high-risk homozygotes at all three loci may have a 250-fold increased risk compared to baseline. However, the identification of genetic factors has not resulted in therapeutic strategies to modify the disease so far and additional genetic and environmental factors are yet to be discovered in order to influence the onset and the progression of AMD.
Mol Vis 2007 Feb 07
PMID:An update on the genetics of age-related macular degeneration. 1732 25

Age-related macular degeneration (AMD) is a devastating disorder of the central retina, causing significant visual impairment for 7.5 million elderly Americans. Abnormal regulation of the complement system likely caused by the Y402H polymorphism in the complement factor H gene is a recognized risk factor for AMD, as is the A69S variant in the poorly characterized LOC387715 gene. Recently, polymorphisms in the factor B (CFB) and complement component 2 (CC2) genes were associated with decreased susceptibility to AMD. To validate this association in independent family-based and case-control Caucasian data sets, we genotyped two single-nucleotide polymorphisms (SNPs) in CC2 and four SNPs in CFB. The R32Q variant of CFB was significantly associated with protection from AMD in the family-based data set (P = 0.025). Three SNPs in CC2 and CFB were strongly associated with decreased risk of AMD in the case-control data set (CC2 E318D: P = 0.02; CC2 rs547154: P = 9 x 10(-6); and CFB R32Q P = 2 x 10(-5)). The minor alleles at CC2 rs547154 and CFB R32Q are present in 4% of cases versus 10% of controls, and as these SNPs are in strong linkage disequilibrium (r(2)=0.92), these results likely represent the same protective signal. After controlling for age, Y402H, A69S and smoking, the effect of CFB R32Q remained quite strong (OR 0.21, 95% confidence interval 0.11-0.39; P < 10(-4)). Likelihood ratio testing and conditional analyses in the case-control data set suggest that a weaker, independent protective effect exists for CC2 E318D.
Hum Mol Genet 2007 Aug 15
PMID:Protective effect of complement factor B and complement component 2 variants in age-related macular degeneration. 1757 44


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