Association of single nucleotide polymorphisms in CFH, ARMS2 and HTRA1 genes with risk of age-related macular degeneration in Egyptian patients

A Pilot Application of an iTRAQ-Based Proteomics Screen Estimates the Effects of Cigarette Smokers' Serum on RPE Cells With AMD High-Risk Alleles

PURPOSE

The aim of this study was to explore whether there are interactions between genetic (ARMS2/HTRA1) and environmental factors (cigarette smoking) in the pathogenesis of age-related macular degeneration (AMD).

METHODS

Primary human retinal pigment epithelial (hRPE) cells were obtained from four donors' eyes with AMD high-risk ARMS2/HTRA1 alleles, and two donors' eyes with wild-type alleles were used as controls. The pooled serum from 32 smokers and 35 nonsmokers were collected and used separately to treat hRPE cells. The isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomics was used to identify associated proteins and comparing the differences between AMD high-risk and low-risk HTRA1/ARMS2 alleles after exposure to smokers' serum.

RESULTS

After stimulation with the smokers' serum, 400 differentially expressed proteins (DEPs) were detected in the high-risk allele cells. Several DEPs are involved in neuronal protein degeneration and oxidative stress pathways. The smokers' serum stimulation or HTRA1 overexpression can both upregulate caveolin-1, which was one of the DEPs. Besides, the smokers' serum enhanced the phagocytosis of cultured human RPE cells.

CONCLUSIONS

The study confirmed the AMD high-risk alleles, HTRA1, and cigarette smoking can promote AMD development by regulating caveolin-1 expression.

TRANSLATIONAL RELEVANCE

AMD high-risk alleles and environmental risk factors can promote the occurrence and development of AMD by regulating caveolin-1 expression, upregulation of which will induce apoptotic cell death in response to cellular stress in early AMD conditions.

Association of the HtrA1 rs11200638 Polymorphism with Neovascular Age-Related Macular Degeneration in Indonesia

Introduction

The aim of this study was to investigate the association of the HtrA1 rs11200638 polymorphism with neovascular age-related macular degeneration (nAMD) in Indonesia.

Methods

This case–control study included 80 patients with nAMD and 85 controls. Demographic parameters and whole blood were collected from each participant. Genomic DNA was extracted and used to assess the rs11200638 genotype by PCR and restriction enzyme digestion. Associations between the HtrA1 rs11200638 polymorphism and other risk factors for susceptibility to nAMD were assessed using the logistic regression model.

Results

Significant allelic associations between the HtrA1 polymorphism and nAMD were detected (odds ratio [OR] 8.67; 95% confidence interval [CI] 4.88–15.41; P < 0.001). Genotype analysis showed a statistical difference between the nAMD group and the control group (P < 0.001). In the multiple adjusted logistic regression model, people with the AA genotype were more likely to have nAMD although there was a wide confidence interval (OR 19.65; 95% CI 4.52–85.38; P < 0.001).

Conclusion

Our findings show that the risk of nAMD increased in the presence of risk alleles of HtrA1 rs11200638.

Mitochondria-dependent phase separation of disease-relevant proteins drives pathological features of age-related macular degeneration

Age-related macular degeneration (AMD) damages the retinal pigment epithelium (RPE), the tissue that safeguards photoreceptor health, leading to irreversible vision loss. Polymorphisms in cholesterol and complement genes are implicated in AMD, yet mechanisms linking risk variants to RPE injury remain unclear. We sought to determine how allelic variants in the apolipoprotein E cholesterol transporter modulate RPE homeostasis and function. Using live-cell imaging, we show that inefficient cholesterol transport by the AMD risk-associated ApoE2 increases RPE ceramide, leading to autophagic defects and complement-mediated mitochondrial damage. Mitochondrial injury drives redox state–sensitive cysteine-mediated phase separation of ApoE2, forming biomolecular condensates that could nucleate drusen. The protective ApoE4 isoform lacks these cysteines and is resistant to phase separation and condensate formation. In Abca^–/– Stargardt macular degeneration mice, mitochondrial dysfunction induces liquid-liquid phase separation of p62/SQSTM1, a multifunctional protein that regulates autophagy. Drugs that decrease RPE cholesterol or ceramide prevent mitochondrial injury and phase separation in vitro and in vivo. In AMD donor RPE, mitochondrial fragmentation correlates with ApoE and p62 condensates. Our studies demonstrate that major AMD genetic and biological risk pathways converge upon RPE mitochondria, and identify mitochondrial stress-mediated protein phase separation as an important pathogenic mechanism and promising therapeutic target in AMD.

Association of HTRA1 and CFH gene polymorphisms with age-related macular degeneration in Ningbo, China

BACKGROUND

Age-related macular degeneration (AMD) is one of the major causes of blindness, and the incidence of this disease has been increasing in recent years.

OBJECTIVE

To investigate the association between the single nucleotide polymorphisms (SNPs) of the high temperature requirement factor A-1 (HTRA1) and complement factor H (CFH) genes and susceptibility to AMD in Ningbo, China.

METHODS

Ninety-eight patients with AMD and seventy-three controls were recruited at the Sixth Hospital of Ningbo from August 2017 to April 2019 in China. Genomic DNA was extracted from the venous blood provided by the hospital, and the genotypes of the AMD susceptibility genes CFH and HTAR1 were detected by polymerase chain reaction and sequenced directly. The SNPs rs11200638 on the HTRA1 gene and rs3753394 on the CFH gene were selected for genotype and association analysis. The correlations between the different genotypes of HTRA1 and CFH and AMD were analysed by the Chi-squared test.

RESULTS

All the genotypes adhered to the Hardy-Weinberg equilibrium. There were three genotypes (AA, AG and GG) in HTRA1 (rs11200638). The differences in genotypes and allele frequency between the AMD group and the control group were statistically significant (P < 0.05). The A allele was a risk allele (OR: 4.19, 95% Cl: 2.28 ~ 7.70, P < 0.05), with a frequency of 61.7% in patients versus 43.8% in controls. However, the rs3753394 SNP in CFH was not associated with AMD in our study (P > 0.05).

CONCLUSIONS

The rs11200638 SNP of the HTRA1 gene is associated with AMD, and the AA genotype is a risk factor for AMD in the Ningbo population. There is no significant correlation between the rs3753394 SNP of the CFH gene and AMD.

Progress in developing rodent models of age-related macular degeneration (AMD)

Age-related macular degeneration (AMD) is the leading cause of irreversible central vision loss, typically affecting individuals from mid-life onwards. Its multifactorial aetiology and the lack of any effective treatments has spurred the development of animal models as research and drug discovery tools. Several rodent models have been developed which recapitulate key features of AMD and provide insights into its underlying pathology. These have contributed to making significant progress in understanding the disease and the identification of novel therapeutic targets. However, a major caveat with existing models is that they do not demonstrate the full disease spectrum. In this review, we outline advances in rodent AMD models from the last decade. These models feature various hallmarks associated with AMD, including oxidative stress, hypoxia, immune dysregulation, genetic mutations and environmental risk factors. The review summarises the methods by which each model was created, its pathological characteristics as well as its relation to the disease in humans.

The association between complement factor H rs1061170 polymorphism and age-related macular degeneration: a comprehensive meta-analysis stratified by stage of disease and ethnicity

PURPOSE

The strength of association between complement factor H (CFH) rs1061170 polymorphism and age-related macular degeneration (AMD) differs between AMD subtypes and ethnicities. The main aim was to provide a systematic review and an updated meta-analysis stratified by stage of disease and ethnicity.

METHODS

A literature search in the PubMed-Medline, EMBASE and Web of Science databases was conducted to identify epidemiological studies, published before September 2017, that included at least twp comparison groups (a control group with no signs of AMD and a case group of AMD patients). Genotype distribution, phenotype of the cases, ethnicity, mean age and gender ratio were collected. Odds ratios (ORs) and 95%CIs were estimated under the allelic, homozygous and heterozygous models. Sensitivity and subgroup analyses, by AMD subtype and ethnicity, were performed.

RESULTS

The meta-analysis included data of 27 418 AMD patients and 32 843 controls from 76 studies. In Caucasians, the rs1061170 showed a significant association with early AMD (OR: 1.44; 95%CI 1.27-1.63), dry AMD (OR: 2.90; 95%CI 1.89-4.47) and wet AMD (OR: 2.46; 95%CI 2.15-2.83), under an allelic model. In Asians, the rs1061170 showed a significant association with advanced AMD (OR: 2.09; 95%CI 1.67-2.60), especially wet AMD (OR: 2.24; 95%CI 1.81-2.77).

CONCLUSION

Our work provides a more comprehensive meta-analysis of studies investigating the effect of the CFH rs1061170 polymorphism on AMD risk. These findings not only improve the assessment of disease risk associated with the polymorphism, but also constitute a scientific background to be translated into clinical practice for AMD prevention.

Association of HTRA1 rs11200638 with age-related macular degeneration (AMD) in Brazilian patients

Age-related macular degeneration is a multifactorial disease that can lead to vision impairment in older individuals. Although the etiology of age-related macular degeneration remains unknown, risk factors include age, ethnicity, smoking, hypertension, obesity, and genetic factors. Two main loci have been identified through genome-wide association studies, on chromosomes 1 and 10. Among the variants located at the 10q26 region, rs11200638, located at the HTRA1 gene promoter, has been associated with age-related macular degeneration in several populations and is considered the main polymorphism. We conducted a replication case-control study to analyze the frequency and participation of rs11200638 in the etiology of age-related macular degeneration in a sample of patients and controls from the State of São Paulo, Brazil, through polymerase chain reaction and enzymatic digestion. The frequency of the A allele was 57.60% in patients with age-related macular degeneration and 36.45% in controls (p value < 1e-07), representing a 2.369-fold higher risk factor for the disease. Both the AA and AG genotypes were observed more frequently in the age-related macular degeneration group compared to the control group (p = 1.21e-07 and 0.0357, respectively). No statistically significant results were observed after stratification in dry versus wet types or advanced versus non-advanced forms. To our knowledge, this is the first time the association between rs11200638 and overall age-related macular degeneration has been reported in South America.

Genetic variants in the SKIV2L gene in exudative age-related macular degeneration in the Japanese population

BACKGROUND

To investigate whether genetic variant in superkiller viralicidic activity 2-like (SKIV2L) gene is associated with exudative age-related macular degeneration (AMD) including neovascular AMD, polypoidal choroidal vasculopathy (PCV), and retinal angiomatous proliferation (RAP).

MATERIALS AND METHODS

A total of 517 patients with exudative AMD comprised of 157patients with neovascular AMD, 333 patients with PCV, and 27patients with RAP, and 205 controls were enrolled in this study. Rs429608 inSKIV2L, rs800292 in complement factor H (CFH), rs10490924 in age-related maculopathy susceptibility2 (ARMS2) gene was genotyped using TaqMan technology. Logistic regression analysis was performed to correlate the risk for exudative AMD with demographic and genetic factors.

RESULTS

The A allele frequency of rs429608 in the SKIV2L gene was significantly higher in controls (13.9%) than in those with neovascular AMD (5.7%, p = 0.002), PCV (7.2%, p = 0.003) and RAP (3.7%, p = 0.0345). After adjusting for age, gender, ARMS2 A69S, and CFHI62V, the A allele of rs429608 was significantly protective against neovascular AMD (odds ratio [OR] 0.24, 95% confidence interval [CI] 0.122-0.484, p < 0.001), PCV (OR 0.43, 95% CI 0.262-0.704, p = 0.001), RAP (OR 0.09, 95% CI 0.014-0.581, p = 0.011).

CONCLUSIONS

A SKIV2L variant was associated with protection against exudative AMD regardless of subtypes in the Japanese population.

Genetic and clinical factors associated with reticular pseudodrusen in exudative age-related macular degeneration

BACKGROUNDS

Reticular pseudodrusen (RPD) is considered to be a distinct entity from soft drusen and a risk factor for age-related macular degeneration (AMD). In the present study, we investigate the genetic and clinical factors associated with reticular pseudodrusen (RPD) in patients with exudative AMD, including polypoidal choroidal vasculopathy (PCV), typical neovascular AMD, and retinal angiomatous proliferation (RAP).

METHODS

The presence or absence of RPD was studied among 408 patients with exudative AMD in at least one eye, and the clinical characteristics of those with RPD were investigated as well as genetic polymorphisms of ARMS2 A69S (rs10490924) and CFH I62V (rs800292). Subfoveal choroidal thickness was also evaluated in a limited number of subjects using the EDI mode of spectral-domain optical coherence tomography.

RESULTS

The prevalence of RPD was significantly higher in RAP eyes than in typical neovascular AMD or in PCV eyes (38.2% of 26 eyes, 13.6% of 132 eyes and 0% of 250 eyes respectively, P < 0.0001). RPD was significantly more prevalent in the elderly (P < 0.0001) and female (P < 0.0001) subjects. The subfoveal choroidal thickness was thinner in eyes with RPD than in those without (129.7 ± 61.7 μm vs 42.6 ± 84.9 μm, P < 0.0001). The frequency of risk variants of ARMS2 A69S was significantly higher in eyes with RPD than in those without RPD (85.7% vs 63.8%, P = 0.0009), although the frequency of CFH I62V was not significantly different between those with and without RPD. Logistic regression analysis revealed that age (odds ratio [OR]:1.10; 95% confidence interval [CI]: 1.04-1.18; p = 0.002), female gender (OR:4.26; 95%CI: 1.72-10.4; p = 0.002), T-allele at ARMS2 A69S (OR: 3.23; 95%CI: 1.36-7.68; p = 0.008) and RAP (OR: 4.25; 95%CI:1.49-12.1; p = 0.007) were risk factors for RPD.

CONCLUSIONS

Among eyes with exudative AMD, RPD is more common in eyes with RAP having a thin choroid at the fovea, especially in old, female patients with the risk variant of ARMS2 A69S.