Increased expression of multifunctional serine protease, HTRA1, in retinal pigment epithelium induces polypoidal choroidal vasculopathy in mice

Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 08/2011; 108(35):14578-83. DOI: 10.1073/pnas.1102853108
Source: PubMed


Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in the elderly. Wet AMD includes typical choroidal neovascularization (CNV) and polypoidal choroidal vasculopathy (PCV). The etiology and pathogenesis of CNV and PCV are not well understood. Genome-wide association studies have linked a multifunctional serine protease, HTRA1, to AMD. However, the precise role of HTRA1 in AMD remains elusive. By transgenically expressing human HTRA1 in mouse retinal pigment epithelium, we showed that increased HTRA1 induced cardinal features of PCV, including branching networks of choroidal vessels, polypoidal lesions, severe degeneration of the elastic laminae, and tunica media of choroidal vessels. In addition, HTRA1 mice displayed retinal pigment epithelium atrophy and photoreceptor degeneration. Senescent HTRA1 mice developed occult CNV, which likely resulted from the degradation of the elastic lamina of Bruch's membrane and up-regulation of VEGF. Our results indicate that increased HTRA1 is sufficient to cause PCV and is a significant risk factor for CNV.

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Available from: Chio Oka, Jan 14, 2014
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    • "The HTRA1 gene polymorphisms are associated with the susceptibility of AMD and PCV [41]. However, overexpression of HTRA1 protein, human serine protease, in mice RPE caused PCV but not AMD, and the degeneration of the choroid vessels was much more severe than that of BM [18]. Moreover, our previous genetic study showed that a common variant (rs10757278) on chromosome 9p21 was associated with PCV but not with nAMD in a Chinese population [42]. "
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    ABSTRACT: Age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) are the leading causes of vision loss in the elderly Asian population. Previous studies have confirmed that abnormal extracellular matrix (ECM) metabolism plays an important role in the pathogenesis of AMD and PCV. However, the dynamic metabolism of the ECM is closely regulated by matrix metalloproteinases (MMPs) and tissue metalloproteinase inhibitors (TIMPs). Whether MMPs and TIMPs participate in the pathogenesis of AMD and PCV remains unclear. The aim of this study was to investigate the correlation between circulating MMP and TIMP levels and AMD and PCV. The serum levels of MMPs (MMP1, MMP2, MMP3, and MMP9) and TIMPs (TIMP1 and TIMP3) were quantified using enzyme-linked immunosorbent assays in four groups of subjects (n=342): early AMD (group 1, n=75), neovascular AMD (group 2, n=89), PCV (group 3, n=98), and age- and gender-matched controls (group 4, n=80). The mean concentrations of the two gelatinases, MMP2 and MMP9, in the PCV group were significantly higher than that of the control (p=0.001, p<0.001, respectively), early AMD (both p<0.001), and neovascular AMD (p=0.005, p=0.001, respectively) groups. Moreover, the serum MMP2 concentration was positively correlated with the serum MMP9 concentration in the PCV group (r=0.822, p<0.001). However, the mean concentrations of MMP2 and MMP9 in the early AMD and neovascular AMD groups were not significantly different from that of the control group (p>0.05). The mean serum levels of MMP1, MMP3, TIMP1, and TIMP3 were not significantly different among the four groups. This pilot study first reveals a link between increased levels of circulating gelatinases (MMP2 and MMP9) and PCV but not AMD, which may provide a biologically relevant marker of ECM metabolism in patients with PCV. This finding suggests that the two disorders may have different molecular mechanisms.
    Full-text · Article · Mar 2013 · Molecular vision
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    • "Dysregulation of TGF-β-family signaling results in hereditary vascular disorders [29]. However, previous studies investigating the functional effects of HTRA1 on PCV or AMD mainly focused on RPE cells or Bruch's membrane [8], [17], [18], [30], and potential effects on vascular endothelial cells have been only rarely observed. "
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    ABSTRACT: Multiple genetic studies have suggested that high-temperature requirement serine protease (HTRA1) is associated with polypoidal choroidal vasculopathy (PCV). To date, no functional studies have investigated the biological effect of HTRA1 on vascular endothelial cells, essential vascular components involved in polypoidal vascular abnormalities and arteriosclerosis-like changes. In vitro studies were performed to investigate the effect of HTRA1 on the regulation of fibronectin, laminin, vascular endothelial growth factor (VEGF), platelet derived growth factor receptor (PDGFR) and matrix metalloparoteinases 2 (MMP-2) and the role of HTRA1 in choroid-retina endothelial (RF/6A) and human umbilical vein endothelial (HUVEC) cells. Lentivirus-mediated overexpression of HTRA1 was used to explore effects of the protease on RF/6A and HUVEC cells in vitro. HTRA1 overexpression inhibited the proliferation, cell cycle, migration and tube formation of RF/6A and HUVEC cells, effects that might contribute to the early stage of PCV pathological lesions. Fibronectin mRNA and protein levels were significantly down-regulated following the upregulation of HTRA1, whereas the expressions of laminin, VEGF and MMP-2 were unaffected by alterations in HTRA1 expression. The decreased biological function of vascular endothelial cells and the degradation of extracellular matrix proteins, such as fibronectin, may be involved in a contributory role for HTRA1 in PCV pathogenesis.
    Preview · Article · Oct 2012 · PLoS ONE
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    • "Another variant at the 10q26 region, HTRA1 rs11200638, was also confirmed to be associated with PCV. A study reported that HTRA1 transgenic mice had retinal pigment epithelium induced choroidal branching vascular networks, polypoidal lesions, severe degeneration of the elastic laminae, and tunica media of choroidal vessels [47], suggesting that overexpression of HTRA1 may predispose individuals to PCV. To date, whether the LOC387715 or the HTRA1 at 10q26 is the gene responsible for AMD and PCV remains in question because of the strong linkage disequilibrium between them. "
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    ABSTRACT: To investigate the genetic associations of polypoidal choroidal vasculopathy (PCV), the genetic difference between PCV and age-related macular degeneration (AMD), and the genotype-phenotype correlation of PCV. A systematic review and meta-analysis were performed. Published articles about genetic associations of PCV identified from a literature search were reviewed. The following data from individual studies were extracted and analyzed: 1) comparison of genetic polymorphisms between PCV and controls; 2) comparison of genetic polymorphisms between PCV and AMD; and 3) comparison of phenotypes between different genotype groups. A total of 33 articles fulfilled the inclusion criteria. With meta-analyses, variants in four genes were found to be significantly associated with PCV: LOC387715 rs10490924 (n=9, allelic odds ratio [OR]=2.27, p<0.00001), HTRA1 rs11200638 (n=4, OR=2.72, p<0.00001), CFH rs1061170 (n=4, OR=1.72, p<0.00001), CFH rs800292 (n=5, OR=2.10, p<0.00001), and C2 rs547154 (n=3, OR=0.56, p=0.01). LOC387715 rs10490924 was the only variant showing a significant difference between PCV and wet AMD (n=5, OR=0.66, p<0.00001). The risk genotypes of rs10490924 were associated with larger lesion size, greater chance of vitreous hemorrhage, and worse therapeutic response in PCV. LOC387715 rs10490924 was associated with PCV and its clinical manifestations, and showed a discrepant distribution between PCV and AMD. Variants in HTRA1, CFH, and C2 were also associated with PCV.
    Full-text · Article · Apr 2012 · Molecular vision
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