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Yan X, Zhang N, Wei L, Zhang W, Huang T, Li W, Chen W, Yang A, You H. Selective Inhibition of Hepatic Stellate Cell and Fibroblast-derived LOXL1 Attenuates BDL and Mdr2 -/- Induced Cholestatic Liver Fibrosis. Am J Physiol Gastrointest Liver Physiol 2023. [PMID: 37873581 DOI: 10.1152/ajpgi.00004.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
BACKGROUND AND AIMS Lysyl oxidase-like 1 (LOXL1) proteins are amine oxidases that play a crucial role in extracellular matrix remodeling due to their collagen cross-linking and intracellular functions. The role of LOXL1 in cholestatic liver fibrosis remains unexplored. METHODS We measured LOXL1 expression in two murine models of cholestasis (Mdr2 knockout [Mdr2-/-] and bile duct ligation [BDL]). We used adeno-associated virus (AAV) serotype 6-mediated hepatic delivery against LOXL1 (AAV2/6-shLoxl1) to investigate the therapeutic efficacy of targeting LOXL1 in cholestatic liver fibrosis. NIH-3T3 murine fibroblasts were used to investigate the function and regulatory mechanisms of LOXL1 in vitro. RESULTS LOXL1 expression was significantly upregulated in Mdr2 -/- and BDL mice compared to their corresponding controls, predominantly in collagen-rich fibrous septa and portal areas. AAV2/6-shLoxl1 significantly reduced LOXL1 levels in Mdr2-/- and BDL mice, mainly located in desmin-positive hepatic stellate cells (HSCs) and fibroblasts. Concomitant with reduced LOXL1 expression, there was reduced ductular reaction, inflammation, and fibrosis in both Mdr2 -/- and BLD mouse models. Additionally, Loxl1 intervention decreased Ki-67 positive cells in the desmin-positive areas in both Mdr2 -/- and BDL mice. Overexpression of LOXL1 significantly promoted fibroblast proliferation by activating the platelet-derived growth factor receptor and extracellular signal-regulated kinase signaling pathways in vitro. CONCLUSION Our findings demonstrated that selective inhibition of LOXL1 derived from HSCs/fibroblasts attenuated cholestatic liver/biliary fibrosis, inflammation, ductal reaction, and HSC/fibroblast proliferation. Based on our findings LOXL1 could be a potential therapeutic target for cholestatic fibrosis.
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Affiliation(s)
- Xuzhen Yan
- Beijing Clinical Medicine Institute, Beijing Friendship Hospital, Beijing, China
| | - Ning Zhang
- Liver Research Center, Beijing Friendship Hospital, Beijing, China
| | - Luyang Wei
- Department of General Surgery, Beijing Friendship Hospital, Beijing, China
| | - Wen Zhang
- Liver Research Center, Beijing Friendship Hospital, Beijing, China
| | - Tao Huang
- Experimental and Translational Research Center, Beijing Friendship Hospital, Beijing, China
| | - Weiyu Li
- Liver Research Center, Beijing Friendship Hospital, Beijing, China
| | - Wei Chen
- Beijing Friendship Hospital, Beijing, China
| | | | - Hong You
- Liver Research Center, Beijing Friendship Hospital, Beijing, China
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Eliseeva NV, Ponomarenko IV, Churnosov MI. [Study of the functional significance of polymorphic loci of the LOXL1 gene associated with glaucoma according to genome-wide studies (in silico analysis)]. Vestn Oftalmol 2021; 137:22-30. [PMID: 34726854 DOI: 10.17116/oftalma202113705122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Glaucoma is one of the most common eye diseases leading to blindness, and whole-genome studies have shown that genetic factors are important in its formation. Purpose - to perform an in silico analysis of the functional significance of polymorphic loci of the LOXL1 gene associated with glaucoma, using data from wholegenome studies. MATERIAL AND METHODS Using the catalog of genome-wide studies (GWAS) of the National Human Genome Research Institute (https://www.genome.gov/gwastudies/), three polymorphic loci of the LOXL1 gene (rs2165241, rs4886776, rs893818) associated with glaucoma (pseudoexfoliation glaucoma/syndrome) were chosen for the study. Using modern databases on functional genomics (SIFT, PolyPhen-2, HaploReg, GTExportal), the functional significance of these polymorphic loci was assessed (nonsynonymous substitutions, epigenetic effects, association with gene expression, associations with alternative splicing of gene transcripts). RESULTS The work establishes the important functional significance of the rs2165241, rs4886776 and rs893818 polymorphic loci of the LOXL1 gene. They demonstrate significant epigenetic effects (affect the affinity to five transcription factors, are located in the region of promoters and enhancers, in the region of hypersensitivity to DNase-1), are associated with the expression and alternative splicing of three genes (LOXL1, LOXL1-AS1, RP11-24D15.1) in cell cultures, organs and tissues pathogenetically significant for development of glaucoma, are strongly linked to the rs1048661 polymorphism, which causes the replacement of the Arg141Leu amino acid in the LOXL1 polypeptide. CONCLUSION Polymorphic loci of the LOXL1 gene (rs2165241, rs4886776, and rs893818) are of great functional importance (epigenetic, eQTL, and sQTL), which may be the biomedical basis of their associations with glaucoma.
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Affiliation(s)
- N V Eliseeva
- Belgorod State National Research University, Belgorod, Russia
| | - I V Ponomarenko
- Belgorod State National Research University, Belgorod, Russia
| | - M I Churnosov
- Belgorod State National Research University, Belgorod, Russia
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Zhang M, Sun S, Wang L, Wang X, Chen T, Chen Z, Jiang Y. Zonular defects in loxl1-deficient zebrafish. Clin Exp Ophthalmol 2021; 50:62-73. [PMID: 34585825 DOI: 10.1111/ceo.14017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/17/2021] [Accepted: 09/25/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND To investigate the roles of the lysyl oxidase-like 1 (loxl1) gene in zebrafish eye development and the potency of loxl1 deficiency in mimicking the ocular manifestations of exfoliation syndrome (XFS). METHODS CRISPR/Cas9 technology was used to generate a frameshift coding deletion in zebrafish loxl1. Expression profiles and ocular manifestations of the wildtype, heterozygous mutant (loxl1+/- ) and homozygous mutant (loxl1-/- ) zebrafish were analysed in a range of developmental stages from zebrafish larvae to dissected adult zebrafish eyes. RESULTS The loxl1 deficiency caused zonular bundling disorders in juvenile zebrafish and accumulation of pearl-like particles adhering to the adult zebrafish zonule. The bundles appeared to lack form and were thinner in both loxl1+/- and loxl1-/- zebrafish compared with the wildtype (p < 0.01 for all Bonferroni post-hoc analyses). The zonule of loxl1-/- zebrafish appeared stretched, ragged and torn, with isolated fibres also detected. The particles in loxl1-/- zebrafish were more numerous (counts: 92.33 ± 10.02/100 μm2 vs. 58.33 ± 5.03/100 μm2 , p = 0.006), but smaller in size (diameter: 0.21 ± 0.03 μm vs. 0.43 ± 0.04 μm, p = 0.002) compared with those in loxl1+/- . Transmission electron microscopy revealed thinning or even loss of elastic lamina in loxl1+/- Bruch's membrane (BM) (thickness of elastic lamina: 92.94 ± 18.19 nm in the wildtype vs 35.65 ± 14.76 nm in loxl1+/- , p = 0.003). The breakage of BM was observed in loxl1-/- . CONCLUSIONS The loxl1-/- zebrafish is a promising animal model of XFS zonular pathology.
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Affiliation(s)
- Min Zhang
- Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China.,Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shaoyang Sun
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Lei Wang
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Xu Wang
- Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Tianhui Chen
- Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Zexu Chen
- Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Yongxiang Jiang
- Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
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Yang A, Yan X, Xu H, Fan X, Zhang M, Huang T, Li W, Chen W, Jia J, You H. Selective depletion of hepatic stellate cells-specific LOXL1 alleviates liver fibrosis. FASEB J 2021; 35:e21918. [PMID: 34569648 DOI: 10.1096/fj.202100374r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 08/06/2021] [Accepted: 08/27/2021] [Indexed: 12/13/2022]
Abstract
The role of LOXL1 in fibrosis via mediating ECM crosslinking and stabilization is well established; however, the role of hepatic stellate cells (HSCs)-specific LOXL1 in the development of fibrosis remains unknown. We generated HSCs-specific Loxl1-depleted mice (Loxl1Gfap-cre mice) to investigate the HSCs-specific contribution of LOXL1 in the pathogenesis of fibrosis. Loxl1fl/fl mice were used as the control. Furthermore, we used RNA sequencing to explore the underlying changes in the transcriptome. Results of the sirius red staining, type I collagen immunolabeling, and hydroxyproline content analysis, coupled with the reduced expression of profibrogenic genes revealed that Loxl1Gfap-cre mice with CCl4 -induced fibrosis exhibited decreased hepatic fibrosis. In addition, Loxl1Gfap-cre mice exhibited reduced macrophage tissue infiltration by CD68-positive cells and decreased expression of inflammatory genes compared with the controls. RNA sequencing identified integrin α8 (ITGA8) as a key modulator of LOXL1-mediated liver fibrosis. Functional analyses showed that siRNA silencing of Itga8 in cultured fibroblasts led to a decline in the LOXL1 expression and inhibition of fibroblast activation. Mechanistic analyses indicated that LOXL1 activated the FAK/PI3K/AKT/HIF1a signaling pathway, and the addition of inhibitors of FAK or PI3K reversed these results via downregulation of LOXL1. Furthermore, HIF1a directly interacted with LOXL1 and upregulated its expression, indicating that LOXL1 can positively self-regulate by forming a positive feedback loop with the FAK/PI3K/AKT/HIF1a pathway. We demonstrated that HSCs-specific Loxl1 deficiency prevented fibrosis, inflammation and that ITGA8/FAK/PI3K/AKT/HIF1a was essential for the function and expression of LOXL1. Knowledge of this approach can provide novel mechanisms and targets to treat fibrosis in the future.
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Affiliation(s)
- Aiting Yang
- Experimental and Translational Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, P.R. China.,Beijing Clinical Medicine Institute, Beijing, P.R. China.,National Clinical Research Center of Digestive Diseases, Beijing, P.R. China
| | - Xuzhen Yan
- National Clinical Research Center of Digestive Diseases, Beijing, P.R. China.,Liver Research Center, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis, Beijing Friendship Hospital, Capital Medical University, Beijing, P.R. China
| | - Hufeng Xu
- Experimental and Translational Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, P.R. China.,Beijing Clinical Medicine Institute, Beijing, P.R. China.,National Clinical Research Center of Digestive Diseases, Beijing, P.R. China
| | - Xu Fan
- National Clinical Research Center of Digestive Diseases, Beijing, P.R. China.,Liver Research Center, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis, Beijing Friendship Hospital, Capital Medical University, Beijing, P.R. China
| | - Mengyang Zhang
- National Clinical Research Center of Digestive Diseases, Beijing, P.R. China.,Liver Research Center, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis, Beijing Friendship Hospital, Capital Medical University, Beijing, P.R. China
| | - Tao Huang
- Experimental and Translational Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, P.R. China.,Beijing Clinical Medicine Institute, Beijing, P.R. China.,National Clinical Research Center of Digestive Diseases, Beijing, P.R. China
| | - Weiyu Li
- National Clinical Research Center of Digestive Diseases, Beijing, P.R. China.,Liver Research Center, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis, Beijing Friendship Hospital, Capital Medical University, Beijing, P.R. China
| | - Wei Chen
- Experimental and Translational Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, P.R. China.,Beijing Clinical Medicine Institute, Beijing, P.R. China.,National Clinical Research Center of Digestive Diseases, Beijing, P.R. China
| | - Jidong Jia
- Beijing Clinical Medicine Institute, Beijing, P.R. China.,National Clinical Research Center of Digestive Diseases, Beijing, P.R. China.,Liver Research Center, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis, Beijing Friendship Hospital, Capital Medical University, Beijing, P.R. China
| | - Hong You
- Beijing Clinical Medicine Institute, Beijing, P.R. China.,National Clinical Research Center of Digestive Diseases, Beijing, P.R. China.,Liver Research Center, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis, Beijing Friendship Hospital, Capital Medical University, Beijing, P.R. China
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Ayala M, Zetterberg M, Skoog I, Zettergren A. Association of Single Nucleotide Polymorphisms Located in LOXL1 with Exfoliation Glaucoma in Southwestern Sweden. Genes (Basel) 2021; 12:genes12091384. [PMID: 34573365 PMCID: PMC8468303 DOI: 10.3390/genes12091384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 08/27/2021] [Accepted: 09/02/2021] [Indexed: 11/28/2022] Open
Abstract
Introduction: Glaucoma is an optic neuropathy that leads to visual field defects. Genetic mechanisms seem to be involved in glaucoma development. Lysyl Oxidase Like 1 (LOXL1) has been described in previous studies as a predictor factor for exfoliation glaucoma. The present article studied the association between three single nucleotide polymorphisms (SNPs) in the LOXL1 gene and the presence of exfoliation glaucoma in Southwestern Sweden. Methods: Case-control study for genetic association. In total, 136 patients and 1011 controls were included in the study. Patients with exfoliation glaucoma were recruited at the Eye Department of Sahlgrenska University Hospital and Skaraborgs Hospital, Sweden. Controls were recruited from the Gothenburg H70 Birth Cohort Study. Three different SNPs were genotyped: LOXL1_rs3825942, LOXL1_rs2165241 and LOXL1_rs1048661. Results: The distribution of allele frequencies was significantly different between controls and glaucoma patients; for rs3825942 (p = 2 × 10−12), for rs2165241 (p = 3 × 10−16) and for rs1048661 (p = 2 × 10−6). Logistic regression analyses using an additive genetic model, adjusted for sex and age, also showed associations between the studied SNPs and glaucoma (p = 9 × 10−6; p = 2 × 10−14; p = 1 × 10−4). Conclusion: A strong association was found between allele frequencies of three different SNPs (LOXL1_rs3825942, LOXL1_rs2165241, and LOXL1_rs1048661) and the presence of exfoliation glaucoma in a Southwestern Swedish population.
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Affiliation(s)
- Marcelo Ayala
- Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 40530 Gothenburg, Sweden;
- Eye Department, Region Västra Götaland, Skaraborg Hospital/Skövde, 54142 Skövde, Sweden
- Department of Clinical Neuroscience, Karolinska Institute, 17165 Stockholm, Sweden
- Correspondence: ; Tel.: +46-500-431-000
| | - Madeleine Zetterberg
- Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 40530 Gothenburg, Sweden;
- Department of Ophthalmology, Region Västra Götaland, Sahlgrenska University Hospital, 43130 Mölndal, Sweden
| | - Ingmar Skoog
- Region Västra Götaland, Sahlgrenska University Hospital, Psychiatry, Cognition and Old Age Psychiatry Clinic, 40530 Gothenburg, Sweden;
- Neuropsychiatric Epidemiology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, Centre for Ageing and Health (AGECAP) University of Gothenburg, 40530 Gothenburg, Sweden;
| | - Anna Zettergren
- Neuropsychiatric Epidemiology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, Centre for Ageing and Health (AGECAP) University of Gothenburg, 40530 Gothenburg, Sweden;
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Žukauskaitė G, Domarkienė I, Matulevičienė A, Vaitėnienė EM, Arasimavičius J, Smailytė G, Kučinskas V, Ambrozaitytė L. Possible Protective Effect of LOXL1 Variant in the Cohort of Chernobyl Catastrophe Clean-Up Workers. Genes (Basel) 2021; 12:1231. [PMID: 34440405 DOI: 10.3390/genes12081231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/06/2021] [Accepted: 08/08/2021] [Indexed: 11/16/2022] Open
Abstract
Ionising radiation (IR) is an environmental factor known to alter genomes and therefore challenge organisms to adapt. Lithuanian clean-up workers of the Chernobyl nuclear disaster (LCWC) experienced high doses of IR, leading to different consequences. This study aims to characterise a unique protective genomic variation in a relatively healthy LCWC group. This variation influenced their individual reaction to IR and potentially protects against certain diseases such as exfoliation syndrome and glaucoma. Clinical and IR dosage data were collected using a questionnaire to characterise the cohort of 93 LCWC. Genome-wide genotyping using Illumina beadchip technology was performed. The control group included 466 unrelated, self-reported healthy individuals of Lithuanian descent. Genotypes were filtered out from the microarray dataset using a catalogue of SNPs. The data were used to perform association, linkage disequilibrium, and epistasis analysis. Phenotype data analysis showed the distribution of the most common disease groups among the LCWC. A genomic variant of statistical significance (Fishers' exact test, p = 0.019), rs3825942, was identified in LOXL1 (NM_005576.4:c.458G>A). Linkage disequilibrium and epistasis analysis for this variant identified the genes LHFPL3, GALNT6, PIH1D1, ANKS1B, and METRNL as potentially involved in the etiopathogenesis of exfoliation syndrome and glaucoma, which were not previously associated with the disease. The LOXL1 variant is mostly considered a risk factor in the development of exfoliation syndrome and glaucoma. The influence of recent positive selection, the phenomenon of allele-flipping, and the fact that only individuals with the homozygous reference allele have glaucoma in the cohort of the LCWC suggest otherwise. The identification of rs3825942 and other potentially protective genomic variants may be useful for further analysis of the genetic architecture and etiopathogenetic mechanisms of other multifactorial diseases.
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Yang A, Yan X, Fan X, Shi Y, Huang T, Li W, Chen W, Jia J, You H. Hepatic stellate cells-specific LOXL1 deficiency abrogates hepatic inflammation, fibrosis, and corrects lipid metabolic abnormalities in non-obese NASH mice. Hepatol Int 2021; 15:1122-1135. [PMID: 34014450 DOI: 10.1007/s12072-021-10210-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 05/05/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND AND AIMS Lysyl oxidase-like-1 (LOXL1), a vital cross-linking enzyme in extracellular matrix (ECM) maintenance, promotes fibrosis via enhancement of ECM stability. However, the potential role of LOXL1 in the pathogenesis of nonalcoholic steatohepatitis (NASH) has not been previously studied. METHODS We generated Loxl1fl/fl mice to selectively delete LOXL1 in hepatic stellate cells (HSCs) (Loxl1fl/flGfapcre; Loxl1fl/fl as littermate controls) and then examined liver pathology and metabolic profiles in Loxl1fl/flGfapcre fed with either a choline-deficient L-amino acid-defined (CDAA) diet or an isocaloric control diet for 16 weeks. Thereafter, the findings from the animal model were confirmed in 23 patients with biopsy-proven non-alcoholic fatty liver disease (NAFLD). RESULTS LOXL1 was significantly increased in CDAA induced non-obese NASH compared with the control diet, and LOXL1 deficient in HSCs ameliorated CDAA-induced inflammation and fibrosis, with reduced expression of pro-inflammation and pro-fibrogenic genes in the HSCs-specific LOXL1 knockout mice model. Interestingly, LOXL1 deficient in HSCs could attenuate hepatic steatosis and reverse the metabolic disorder by restoring adipose tissue function without altering the effect of hepatic lipogenesis gene expression in non-obese NASH model. More importantly, analyses of serum LOXL1 and leptin levels from NAFLD patients revealed that LOXL1 was positively correlated with histological fibrosis progression, whereas it was inversely correlated with leptin levels, especially in non-obese NAFLD patients. CONCLUSION LOXL1 may contribute to fibrosis progression in non-obese NAFLD, and HSCs-specific knockout of LOXL1 attenuated liver steatosis, inflammation, fibrosis, , and improved lipid metabolic abnormalities. Hence, LOXL1 inhibition may serve as a new therapeutic strategy for NASH.
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Affiliation(s)
- Aiting Yang
- Experimental and Translational Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, People's Republic of China.,Beijing Clinical Medicine Institute, Beijing, 100050, People's Republic of China.,National Clinical Research Center of Digestive Diseases, Beijing, 100050, People's Republic of China
| | - Xuzhen Yan
- Liver Research Center, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis, Beijing Friendship Hospital, Capital Medical University, No. 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China.,National Clinical Research Center of Digestive Diseases, Beijing, 100050, People's Republic of China
| | - Xu Fan
- Liver Research Center, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis, Beijing Friendship Hospital, Capital Medical University, No. 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China.,National Clinical Research Center of Digestive Diseases, Beijing, 100050, People's Republic of China
| | - Yiwen Shi
- Liver Research Center, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis, Beijing Friendship Hospital, Capital Medical University, No. 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China.,National Clinical Research Center of Digestive Diseases, Beijing, 100050, People's Republic of China
| | - Tao Huang
- Experimental and Translational Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, People's Republic of China.,Beijing Clinical Medicine Institute, Beijing, 100050, People's Republic of China.,National Clinical Research Center of Digestive Diseases, Beijing, 100050, People's Republic of China
| | - Weiyu Li
- Liver Research Center, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis, Beijing Friendship Hospital, Capital Medical University, No. 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China.,National Clinical Research Center of Digestive Diseases, Beijing, 100050, People's Republic of China
| | - Wei Chen
- Experimental and Translational Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, People's Republic of China.,Beijing Clinical Medicine Institute, Beijing, 100050, People's Republic of China.,National Clinical Research Center of Digestive Diseases, Beijing, 100050, People's Republic of China
| | - Jidong Jia
- Liver Research Center, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis, Beijing Friendship Hospital, Capital Medical University, No. 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China.,Beijing Clinical Medicine Institute, Beijing, 100050, People's Republic of China.,National Clinical Research Center of Digestive Diseases, Beijing, 100050, People's Republic of China
| | - Hong You
- Liver Research Center, Beijing Key Laboratory of Translational Medicine in Liver Cirrhosis, Beijing Friendship Hospital, Capital Medical University, No. 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China. .,Beijing Clinical Medicine Institute, Beijing, 100050, People's Republic of China. .,National Clinical Research Center of Digestive Diseases, Beijing, 100050, People's Republic of China.
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Papadopoulou MK, Chatziralli I, Tzika K, Chiras D, Kitsos G, Kroupis C. Correlation of the intronic LOXL1 polymorphism rs11638944 with pseudoexfoliation syndrome and glaucoma in a Greek population. Ophthalmic Genet 2021; 42:405-411. [PMID: 33792495 DOI: 10.1080/13816810.2021.1904420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND The purpose of this study is the development and validation of a novel and robust genotyping method for a new lysyl oxidase-like 1 (LOXL1) intronic polymorphism (rs11638944, C > G) and the investigation of its potential association with pseudoexfoliation syndrome (PXS) and pseudoexfoliation glaucoma (PXG) in a Greek population. MATERIAL AND METHODS 242 DNA samples from 49 PXS, 64 PXG, 50 primary open-angle glaucoma (POAG) patients and 79 healthy age-matched controls were analyzed. Novel methodologies were developed and optimized, in order to genotype the intronic LOXL1 polymorphism: a) a real-time qPCR and melting curve analysis in the Light Cycler platform for rapid and cost-effective analysis and, b) a conventional PCR-RFLP method for analysis of a small number of samples. In selected samples, validity was checked with the reference DNA Sequencing method. RESULTS The real-time qPCR methodology was reliable, demonstrating good efficiency, reproducibility, accuracy in genotyping (100% concordance with the PCR-RFLP method and DNA Sequencing), with good allele discrimination (Tm = 53.26°C for C allele, Tm = 61.83°C for G allele, ΔTm = 8.57°C). The results were characterized by Hardy-Weinberg equilibrium in all groups. An increase from 18% in healthy controls to 61% in PXS patients was detected for the G/G homozygote thus, the C allele is protective for PXS with OR = 0.22 (95%CI: 0.11-0.42, p < .0001). Moreover, an increase from 18% in healthy controls to 70% in PXG patients was detected for the G/G homozygote thus, the C allele is protective for PXG with OR = 0.13 (95%CI: 0.06-0.25, p < .0001). CONCLUSIONS A statistically significant association was verified for the intronic LOXL1 polymorphism rs11638944 and PXS/PXG in a Greek population.
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Affiliation(s)
- Maria-Kyriaki Papadopoulou
- Department of Clinical Biochemistry and Molecular Diagnostics, Attikon General University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Irini Chatziralli
- 2nd Department of Ophthalmology, Attikon General University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Konstantina Tzika
- Department of Clinical Biochemistry and Molecular Diagnostics, Attikon General University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitrios Chiras
- Department of Ophthalmology, University Hospital of Ioannina, Ioannina, Greece
| | - George Kitsos
- Department of Ophthalmology, University Hospital of Ioannina, Ioannina, Greece
| | - Christos Kroupis
- Department of Clinical Biochemistry and Molecular Diagnostics, Attikon General University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
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Sflomos G, Battista L, Aouad P, De Martino F, Scabia V, Stravodimou A, Ayyanan A, Ifticene‐Treboux A, Bucher P, Fiche M, Ambrosini G, Brisken C. Intraductal xenografts show lobular carcinoma cells rely on their own extracellular matrix and LOXL1. EMBO Mol Med 2021; 13:e13180. [PMID: 33616307 PMCID: PMC7933935 DOI: 10.15252/emmm.202013180] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 12/23/2020] [Accepted: 01/05/2021] [Indexed: 12/28/2022] Open
Abstract
Invasive lobular carcinoma (ILC) is the most frequent special histological subtype of breast cancer, typically characterized by loss of E-cadherin. It has clinical features distinct from other estrogen receptor-positive (ER+ ) breast cancers but the molecular mechanisms underlying its characteristic biology are poorly understood because we lack experimental models to study them. Here, we recapitulate the human disease, including its metastatic pattern, by grafting ILC-derived breast cancer cell lines, SUM-44 PE and MDA-MB-134-VI cells, into the mouse milk ducts. Using patient-derived intraductal xenografts from lobular and non-lobular ER+ HER2- tumors to compare global gene expression, we identify extracellular matrix modulation as a lobular carcinoma cell-intrinsic trait. Analysis of TCGA patient datasets shows matrisome signature is enriched in lobular carcinomas with overexpression of elastin, collagens, and the collagen modifying enzyme LOXL1. Treatment with the pan LOX inhibitor BAPN and silencing of LOXL1 expression decrease tumor growth, invasion, and metastasis by disrupting ECM structure resulting in decreased ER signaling. We conclude that LOXL1 inhibition is a promising therapeutic strategy for ILC.
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Affiliation(s)
- George Sflomos
- ISREC ‐ Swiss Institute for Experimental Cancer ResearchSchool of Life SciencesEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - Laura Battista
- ISREC ‐ Swiss Institute for Experimental Cancer ResearchSchool of Life SciencesEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - Patrick Aouad
- ISREC ‐ Swiss Institute for Experimental Cancer ResearchSchool of Life SciencesEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - Fabio De Martino
- ISREC ‐ Swiss Institute for Experimental Cancer ResearchSchool of Life SciencesEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - Valentina Scabia
- ISREC ‐ Swiss Institute for Experimental Cancer ResearchSchool of Life SciencesEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | | | - Ayyakkannu Ayyanan
- ISREC ‐ Swiss Institute for Experimental Cancer ResearchSchool of Life SciencesEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | | | - RLS
- Réseau Lausannois du Sein (RLS)LausanneSwitzerland
| | - Philipp Bucher
- ISREC ‐ Swiss Institute for Experimental Cancer ResearchSchool of Life SciencesEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - Maryse Fiche
- Réseau Lausannois du Sein (RLS)LausanneSwitzerland
- International Cancer Prevention InstituteEpalingesSwitzerland
| | - Giovanna Ambrosini
- ISREC ‐ Swiss Institute for Experimental Cancer ResearchSchool of Life SciencesEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - Cathrin Brisken
- ISREC ‐ Swiss Institute for Experimental Cancer ResearchSchool of Life SciencesEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
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10
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Yuan R, Li Y, Yang B, Jin Z, Xu J, Shao Z, Miao H, Ren T, Yang Y, Li G, Song X, Hu Y, Wang X, Huang Y, Liu Y. LOXL1 exerts oncogenesis and stimulates angiogenesis through the LOXL1-FBLN5/αvβ3 integrin/FAK-MAPK axis in ICC. Mol Ther Nucleic Acids 2021; 23:797-810. [PMID: 33614230 PMCID: PMC7868718 DOI: 10.1016/j.omtn.2021.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 01/05/2021] [Indexed: 02/07/2023]
Abstract
Aberrant expression of lysyl oxidase-like 1 (LOXL1) reportedly leads to fibrous diseases. Recent studies have revealed its role in cancers. In this study, we observed an elevated level of LOXL1 in the tissues and sera of patients with intrahepatic cholangiocarcinoma (ICC) compared with levels in nontumor tissues and sera of unaffected individuals. Overexpression of LOXL1 in RBE and 9810 cell lines promoted cell proliferation, colony formation, and metastasis in vivo and in vitro and induced angiogenesis. In contrast, depletion of LOXL1 showed the opposite effects. We further showed that LOXL1 interacted with fibulin 5 (FBLN5), which regulates angiogenesis, through binding to the αvβ3 integrin in an arginine-glycine-aspartic (Arg-Gly-Asp) domain-dependent mechanism and enhanced the focal adhesion kinase (FAK)-mitogen-activated protein kinase (MAPK) signaling pathway inside vascular endothelial cells. Our findings shed light on the molecular mechanism underlying LOXL1 regulation of angiogenesis in ICC development and indicate that the LOXL1-FBLN5/αvβ3 integrin/FAK-MAPK axis might be the critical pathological link leading to angiogenesis in ICC.
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Affiliation(s)
- Ruiyan Yuan
- State Key Laboratory of Oncogenes and Related Genes, Department of General Surgery, Shanghai Key Laboratory of Biliary Tract Disease Research, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Yang Li
- State Key Laboratory of Oncogenes and Related Genes, Department of General Surgery, Shanghai Key Laboratory of Biliary Tract Disease Research, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Bo Yang
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Department of Surgery, First Affiliated Hospital of Wenzhou Medical University, Baixiang Road, Wenzhou 325000, China
| | - Zhaohui Jin
- State Key Laboratory of Oncogenes and Related Genes, Department of General Surgery, Shanghai Key Laboratory of Biliary Tract Disease Research, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Jiacheng Xu
- Endoscopy Center and Endoscopy Research Institute, Zhongshan Hospital, Fudan University, No. 180 Fenglin Road, Shanghai 200032, China
| | - Ziyu Shao
- State Key Laboratory of Oncogenes and Related Genes, Department of General Surgery, Shanghai Key Laboratory of Biliary Tract Disease Research, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Huijie Miao
- State Key Laboratory of Oncogenes and Related Genes, Department of General Surgery, Shanghai Key Laboratory of Biliary Tract Disease Research, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Tai Ren
- State Key Laboratory of Oncogenes and Related Genes, Department of General Surgery, Shanghai Key Laboratory of Biliary Tract Disease Research, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Yang Yang
- State Key Laboratory of Oncogenes and Related Genes, Department of General Surgery, Shanghai Key Laboratory of Biliary Tract Disease Research, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Guoqiang Li
- State Key Laboratory of Oncogenes and Related Genes, Department of General Surgery, Shanghai Key Laboratory of Biliary Tract Disease Research, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Xiaoling Song
- State Key Laboratory of Oncogenes and Related Genes, Department of General Surgery, Shanghai Key Laboratory of Biliary Tract Disease Research, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Yunping Hu
- State Key Laboratory of Oncogenes and Related Genes, Department of General Surgery, Shanghai Key Laboratory of Biliary Tract Disease Research, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Xu'an Wang
- Department of Biliary-Pancreatic Surgery, Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200120, China
| | - Ying Huang
- State Key Laboratory of Oncogenes and Related Genes, Department of General Surgery, Shanghai Key Laboratory of Biliary Tract Disease Research, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Yingbin Liu
- Department of Biliary-Pancreatic Surgery, Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200120, China
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11
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Greene AG, Eivers SB, McDonnell F, Dervan EWJ, O'Brien CJ, Wallace DM. Differential Lysyl oxidase like 1 expression in pseudoexfoliation glaucoma is orchestrated via DNA methylation. Exp Eye Res 2020; 201:108349. [PMID: 33188817 DOI: 10.1016/j.exer.2020.108349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 10/14/2020] [Accepted: 11/03/2020] [Indexed: 10/23/2022]
Abstract
Pseudoexfoliation syndrome (PXF) is the most common cause of secondary open angle glaucoma worldwide. Single nucleotide polymorphisms (SNPs) in the gene Lysyl oxidase like 1 (LOXL1) are strongly associated with the development of pseudoexfoliation glaucoma (PXFG). However, these SNPs are also present in 50-80% of the general population, suggestive of other factors being involved in the pathogenesis of PXFG. In this study, we aimed to investigate the influence of epigenetic regulation, specifically DNA methylation, on LOXL1 expression in PXFG using human tenons fibroblasts (HTFs), aqueous humour and serum samples from donors with and without PXFG. LOXL1 expression in HTFs was measured by qPCR and Western Blotting and LOXL1 concentration in aqueous humour was determined by ELISA. Global DNA methylation levels were quantified using an ELISA for 5-methylcytosine. MeDIP assays assessed the methylation status of the LOXL1 promoter region. Expression of methylation-associated enzymes (DNMT1, DNMT3a and MeCP2) were determined by qPCR and inhibited by 0.3 μM 5-azacytidine (5-aza). Results showed that LOXL1 expression was significantly decreased in PXFG HTFs compared with Control HTFs at gene (Fold change 0.37 ± 0.05, P < 0.01) level and showed a decrease, when measured at the protein level (Fold change 0.65 ± 0.42, P = 0.22), however this was not found to be significant. LOXL1 concentration was increased in the aqueous of PXFG patients compared with Controls (2.76 ± 0.78 vs. 1.79 ± 0.33 ng/ml, P < 0.01). Increased global methylation (56.07% ± 4.87% vs. 32.39% ± 4.29%, P < 0.01) was observed in PXFG HTFs compared with Control HTFs, as was expression of methylation-associated enzymes (DNMT1 1.58 ± 0.30, P < 0.05, DNMT3a 1.89 ± 0.24, P < 0.05, MeCP2 1.63 ± 0.30, P < 0.01). Methylation-associated enzymes were also increased when measured at protein level (DNMT1 5.70 ± 2.64, P = 0.04, DNMT3a 1.79 ± 1.55, P = 0.42, MeCP2 1.64 ± 1.33, P = 0.45). LOXL1 promoter methylation was increased in patients with PXFG compared to Control patients in both blood (3.98 ± 2.24, 2.10 ± 1.29, P < 0.05) and HTF cells (37.31 ± 22.0, 8.66 ± 10.40, P < 0.01). Treatment of PXFG HTFs with in 5-azacytidine increased LOXL1 expression when compared with untreated PXFG HTFs (Fold change 2.26 ± 0.67, P < 0.05). These data demonstrate that LOXL1 expression is altered in PXFG via DNA methylation and that reversal of these epigenetic changes may represent future potential therapeutic targets in the management of PXFG.
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Affiliation(s)
- Alison G Greene
- Clinical Research Centre, School of Medicine, University College Dublin, Ireland
| | - Sarah B Eivers
- Clinical Research Centre, School of Medicine, University College Dublin, Ireland
| | - Fiona McDonnell
- Clinical Research Centre, School of Medicine, University College Dublin, Ireland
| | - Edward W J Dervan
- Department of Ophthalmology, Mater Misericordiae University Hospital, Eccles Street, Dublin 7, Ireland
| | - Colm J O'Brien
- Clinical Research Centre, School of Medicine, University College Dublin, Ireland; Department of Ophthalmology, Mater Misericordiae University Hospital, Eccles Street, Dublin 7, Ireland
| | - Deborah M Wallace
- Clinical Research Centre, School of Medicine, University College Dublin, Ireland.
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12
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Hu L, Wang J, Wang Y, Wu L, Wu C, Mao B, Maruthi Prasad E, Wang Y, Chin YE. LOXL1 modulates the malignant progression of colorectal cancer by inhibiting the transcriptional activity of YAP. Cell Commun Signal 2020; 18:148. [PMID: 32912229 PMCID: PMC7488294 DOI: 10.1186/s12964-020-00639-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 08/07/2020] [Indexed: 12/24/2022] Open
Abstract
Background LOX-like 1 (LOXL1) is a lysyl oxidase, and emerging evidence has revealed its effect on malignant cancer progression. However, its role in colorectal cancer (CRC) and the underlying molecular mechanisms have not yet been elucidated. Methods LOXL1 expression in colorectal cancer was detected by immunohistochemistry, western blotting and real-time PCR. In vitro, colony formation, wound healing, migration and invasion assays were performed to investigate the effects of LOXL1 on cell proliferation, migration and invasion. In vivo, metastasis models and mouse xenografts were used to assess tumorigenicity and metastasis ability. Molecular biology experiments were utilized to reveal the underlying mechanisms by which LOXL1 modulates the Hippo pathway. Results LOXL1 was highly expressed in normal colon tissues compared with cancer tissues. In vitro, silencing LOXL1 in CRC cell lines dramatically enhanced migration, invasion, and colony formation, while overexpression of LOXL1 exerted the opposite effects. The results of the in vivo experiments demonstrated that the overexpression of LOXL1 in CRC cell lines drastically inhibited metastatic progression and tumour growth. Mechanistically, LOXL1 inhibited the transcriptional activity of Yes-associated protein (YAP) by interacting with MST1/2 and increasing the phosphorylation of MST1/2. Conclusions LOXL1 may function as an important tumour suppressor in regulating tumour growth, invasion and metastasis via negative regulation of YAP activity. Video abstract
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Affiliation(s)
- Lin Hu
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Jing Wang
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Yunliang Wang
- Department of General surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Linpeng Wu
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Chao Wu
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Bo Mao
- School of Biology and Basic Medical Science, Soochow University, Suzhou, China
| | - E Maruthi Prasad
- Department of Cell Biology and Genetics, Shenzhen key of Laboratory of Translational medicine of Tumor, Shenzhen University Health science center, Shenzhen, China
| | - Yuhong Wang
- Department of Pathology, The First Affiliated Hospital of Soochow University, Suzhou, China.
| | - Y Eugene Chin
- Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China.
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13
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Deng M, Liu C, Jiang W, Wang F, Zhou J, Wang D, Wang Y. A novel genetic variant associated with benign paroxysmal positional vertigo within the LOXL1. Mol Genet Genomic Med 2020; 8:e1469. [PMID: 32827243 PMCID: PMC7549573 DOI: 10.1002/mgg3.1469] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 07/14/2020] [Accepted: 07/28/2020] [Indexed: 11/24/2022] Open
Abstract
Background Benign paroxysmal positional vertigo (BPPV) is a common, self‐limited, and favorable prognostic peripheral vestibular disorder. BPPV is transmitted in an autosomal dominant fashion, but most cases occur sporadically. Little research has been reported regarding the mutation spectrum of sporadic BPPV in a large cohort. This study attempted to identify the causative candidate variants associated with BPPV in VDR, LOXL1, and LOXL1‐AS1. Methods An amplicon‐targeted next‐generation sequencing (NGS) method for VDR, LOXL1, and LOXL1‐AS1, was completed in 726 BPPV patients and 502 normal controls. A total of 30 variants (20 variants from VDR, nine variants from LOXL1, seven variants from LOXL1‐AS1) were identified in these two groups. Results Three of 30 variants were nonsynonymous mutations, but no significant difference was found between the BPPV group and the control group via association analysis. A single nucleotide variant (SNV), rs1078967, was identified that is located in intron 1 of LOXL1. The allelic frequency distribution differed significantly between the BPPV group and the control group (p = 0.002). Genotypic frequency was also significantly different (p = 0.006), as determined by gene‐based analyses. Conclusion This report is the first to analyze the variant spectrum of BPPV in a large Chinese population.
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Affiliation(s)
- Mingzhu Deng
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Chen Liu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Weiqing Jiang
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Fei Wang
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Juan Zhou
- Bio-X Institute, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University, Shanghai, China
| | - Dong Wang
- Bio-X Institute, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University, Shanghai, China
| | - Yonggang Wang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Headache Center, China National Clinical Research Center for Neurological Diseases, Beijing, China
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14
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Chen H, Mo M, Liu GY, Gong YM, Yu KD, Xu GZ. Interaction of two functional genetic variants LOXL1 rs1048661 and VEGFA rs3025039 on the risk of age-related macular degeneration in Chinese women. Ann Transl Med 2020; 8:818. [PMID: 32793663 PMCID: PMC7396242 DOI: 10.21037/atm-20-2447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Cumulative evidence indicates that LOXL1 and VEGF-a play important roles in extracellular matrix formation and angiogenesis, respectively. The disorder of extracellular matrix and angiogenesis are the key factors of pathogenesis of age-related macular degeneration (AMD). We hypothesized that rs1048661 (T>G) in the LOXL1 gene and rs3025039 (C>T) in the VEGFA gene might be associated with risk of AMD. Methods A total of 533 unrelated Chinese subjects, 286 cases (247 with early AMD and 39 with late neovascular AMD) and 247 controls, were included in the study. The gene sequences of LOXL1 rs1048661 and VEGFA rs3025039 were amplified by polymerase chain reaction and genotyped. Interaction between rs1048661 and rs3025039 on AMD risk was also assessed. Results LOXL1 rs1048661 but not VEGFA rs3025039 was associated with a significantly increased risk of AMD. The adjusted odds ratio was 1.6 (95% CI, 1.1-2.5) for rs1048661 TT + GT genotype compared with GG homozygotes in the dominant model analysis. Moreover, there was a significant gene-gene interaction between these two polymorphic loci. In VEGFA rs3025039 CC + CT genotype which indicated sufficient expression of VEGF-a, LOXL1 rs1048661 had odds ratios of 1.7 (95% CI, 1.1-2.7) for early AMD and 3.6 (95% CI, 1.1-12.3) for late neovascular AMD in the dominant model analysis. However, LOXL1 rs1048661 did not confer the risk of AMD in subjects harboring VEGFA rs3025039 TT genotype which indicated decreased expression of VEGF-a. Conclusions Our findings suggest that LOXL1 rs1048661 (T>G) may be involved in the risk of AMD. In addition, LOXL1 rs1048661 and VEGFA rs3025039 interacted to confer the development of AMD, especially for late-stage neovascular AMD. Our data need to be further validated.
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Affiliation(s)
- Han Chen
- Department of Ophthalmology, Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
| | - Miao Mo
- Department of Cancer Prevention & Clinical Statistics Center, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Guang-Yu Liu
- Department of Breast Surgery, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Yang-Ming Gong
- Department of Cancer Control & Prevention, Shanghai Municipal Center for Disease Prevention & Control, Shanghai, China
| | - Ke-Da Yu
- Department of Breast Surgery, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Ge-Zhi Xu
- Department of Ophthalmology, Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, China
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15
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Ghaffari Sharaf M, Damji KF, Unsworth LD. Recent advances in risk factors associated with ocular exfoliation syndrome. Acta Ophthalmol 2020; 98:113-120. [PMID: 31736276 DOI: 10.1111/aos.14298] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 10/13/2019] [Indexed: 12/12/2022]
Abstract
Exfoliation syndrome is generally considered a progressive age-related systemic disorder of the extracellular matrix, which is clinically characterized through the observation of flaky white aggregates on ocular tissues. Exfoliation syndrome is directly linked to exfoliative glaucoma in elderly patients, where it is known as the most common identifiable cause of open-angle glaucoma. Despite the identification of various risk factors associated with exfoliation syndrome, the exact pathogenesis of this syndrome has not been fully elucidated. There is a growing number of genome-wide association studies in different populations around the world to identify genetic factors underlying exfoliation syndrome. Besides variants in LOXL1 and CACNA1A genes, new loci have been recently identified which are believed to be associated with exfoliation syndrome. Among different genetic factors, functional variants might help to better understand mechanisms underlying this systemic disorder. Besides genetic factors, epigenetic regulation of different gene expression patterns has been thought to play a role in its pathogenesis. Other factors have been also considered to be involved in the development of exfoliation syndrome at cellular organelles level where mitochondrial impairment and autophagy dysfunction have been suggested in relation to exfoliation syndrome. This review addresses the most recent findings on genetic factors as well as cellular and molecular mechanisms involved in both the development and progression of exfoliation syndrome.
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Affiliation(s)
- Mehdi Ghaffari Sharaf
- Department of Chemical and Materials Engineering University of Alberta Edmonton Alberta Canada
| | - Karim F. Damji
- Department of Ophthalmology and Visual Sciences University of Alberta Edmonton Alberta Canada
| | - Larry D. Unsworth
- Department of Chemical and Materials Engineering University of Alberta Edmonton Alberta Canada
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Abstract
Exfoliation syndrome (XFS) is an age-related disease defined by the deposition of aggregated fibrous material (XFM) in the peri-cellular space. Principal morbidity occurs in the eye, where XFM accumulates on the anterior ocular tissues. GWAS have found that certain genetic variants of lysyl oxidase-like 1 (LOXL1), a matrix cross-linking enzyme that is required for elastic fiber formation confer risk for the development of XFS, but are not a single causative factor as many genetically affected individuals do not develop XFS or subsequent glaucoma (XFG). We have found that XFG cells display defects in lysosomes, microtubules, autophagy, and mitochondria resembling defects found in cells from age-related syndromes, such as the main neurodegenerative diseases. In the majority of these diseases, the determining cellular factor is a protein containing intrinsically disordered regions (IDRs) and displaying a high propensity for aggregation. We have found that in XFG patient-derived cells, LOXL1 protein is actively subjected to autophagic clearance, suggesting that LOXL1 is undergoing aggregation. In silico analysis demonstrates that LOXL1's first 369 aa constitute an IDR with the highest disorder probability peak centering around the known risk positions. Experimentally, we have found over-expression of either unmodified LOXL1 or fluorescent chimeras preserving the well-structured N-terminus cause copious intracellular aggregation and that aggregation wanes when the high IDR peaks are deleted. Overall, our work suggests that XFS/G results from the aggregation of the LOXL1 protein coupled with a reduction of cellular proteostasis capabilities in aging, resulting in a chronic build-up of LOXL1-containing protein aggregates.
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Affiliation(s)
- Audrey M. Bernstein
- SUNY Upstate Medical University, Department of Ophthalmology and Visual Sciences, Syracuse, NY, United States
| | - Robert Ritch
- Einhorn Clinical Research Center, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, United States
| | - J. Mario Wolosin
- Eye and Vision Research Institute, Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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Schlötzer-Schrehardt U, Zenkel M. The role of lysyl oxidase-like 1 ( LOXL1) in exfoliation syndrome and glaucoma. Exp Eye Res 2019; 189:107818. [PMID: 31563608 DOI: 10.1016/j.exer.2019.107818] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/23/2019] [Accepted: 09/25/2019] [Indexed: 12/27/2022]
Abstract
Exfoliation syndrome (XFS) is an age-related systemic disease that affects the extracellular matrix. It increases the risk of glaucoma (exfoliation glaucoma, XFG) and susceptibility to diseases of elastin-rich connective tissues. LOXL1 (lysyl oxidase-like 1) is still recognized as the major genetic effect locus in XFS and XFG in all populations worldwide, although its genetic architecture is incompletely understood. LOXL1 is a key cross-linking enzyme in elastic fiber formation and remodeling, which is compatible with the pathogenetic concept of XFS as a specific type of elastosis. This review provides an overview on the current knowledge about the role of LOXL1 in the etiology and pathophysiology of XFS and XFG. It covers the known genetic associations at the LOXL1 locus, potential mechanisms of gene regulation, implications of LOXL1 in XFS-associated fibrosis and connective tissue homeostasis, its role in the development of glaucoma and associated systemic diseases, and the currently available LOXL1-based in vivo and in vitro models. Finally, it also identifies gaps in knowledge and suggests potential areas for future research.
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Affiliation(s)
| | - Matthias Zenkel
- Department of Ophthalmology, University of Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany
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18
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Shihadeh W, Khabour O, Khalil MB, Al-Dabbagh A, Al-Hashimi M. Association of LOXL1 gene common sequence variants in Jordanian patients with exfoliation syndrome and exfoliative glaucoma. Int J Ophthalmol 2018; 11:1583-1587. [PMID: 30364215 DOI: 10.18240/ijo.2018.10.02] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 08/09/2018] [Indexed: 01/23/2023] Open
Abstract
AIM To investigate the association between single nucleotide polymorphisms (SNPs) in the LOXL1 gene with exfoliation syndrome/glaucoma (XFS/XFG) among Jordanians. METHODS Sixty-one patients with XFS/XFG and 59 healthy control individuals were recruited in the study. Patients were diagnosed with XFS/XFG using standard clinical examination techniques. The exonic rs1048661 SNP and the intronic rs2165241 SNP in LOXL1 gene were genotyped using sequencing technique. Allele and genotype frequencies were compared between cases and controls using Chi-square analysis. RESULTS The G allele of the rs1048661 SNP and the T allele of the rs2165241 SNP were common in the sample with frequencies of 86.4% and 81.4%, respectively. In addition, there were no significant differences in the genotypic and allelic distributions between patients and controls for rs1048661 SNP (P=0.770, OR=1.21, 95%CI: 0.56-2.60) and for rs2165241 SNP (P=0.605, OR=1.12, 95%CI: 0.59-2.09). In addition, no significant associations were found between haplotypes of the examined SNPs and XFS/XFG in the sample (P>0.05). CONCLUSION Variations in LOXL1 gene may not be associated with XFS/XFG in the Jordanian population. More studies are required to confirm the current findings.
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Affiliation(s)
- Wisam Shihadeh
- Department of Ophthalmology/Special Surgery, Faculty of Medicine, Jordan University of Science & Technology, Irbid 22110, Jordan.,Department of Ophthalmology/Clinical Medical Sciences, Faculty of Medicine, Yarmouk University, Irbid 21163, Jordan
| | - Omar Khabour
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Jordan University of Science & Technology, Irbid 22110, Jordan.,Faculty of Applied Medical Sciences, Taibah University, Al-Medina 42353, Saudi Arabia
| | | | - Alaa Al-Dabbagh
- Department of Ophthalmology/Special Surgery, Faculty of Medicine, Jordan University of Science & Technology, Irbid 22110, Jordan
| | - Mustafa Al-Hashimi
- Department of Ophthalmology/Special Surgery, Faculty of Medicine, Jordan University of Science & Technology, Irbid 22110, Jordan
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Pandav SS, Chakma P, Khera A, Chugh N, Gupta PC, Thattaruthody F, Seth NG, Raj S, Kaushik S, Khullar M, Ram J. Lack of association between lysyl oxidase-like 1 polymorphism in pseudoexfoliation syndrome and pseudoexfoliation glaucoma in North Indian population. Eur J Ophthalmol 2018; 29:431-436. [PMID: 30189755 DOI: 10.1177/1120672118795405] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Pseudoexfoliation syndrome is commonly associated with pseudoexfoliation glaucoma. The two nonsynonymous single-nucleotide polymorphisms rs1048661 (R141L) and rs3825942 (G153D) within exon 1 of LOXL1 gene have been found to confer risk of pseudoexfoliation syndrome and pseudoexfoliation glaucoma in different geographical populations. This study aims to find association between two nonsynonymous single-nucleotide polymorphisms with pseudoexfoliation syndrome and pseudoexfoliation glaucoma in North Indian population. METHODS North Indian subjects clinically diagnosed with pseudoexfoliation syndrome/pseudoexfoliation glaucoma and normal age-matched control were enrolled in the study. Genomic DNA was extracted and the two single-nucleotide polymorphisms of LOXL1 gene were genotyped by polymerase chain reaction and sequencing. The association between single-nucleotide polymorphisms with pseudoexfoliation syndrome/pseudoexfoliation glaucoma was evaluated by chi-square test. RESULTS A total of 30 pseudoexfoliation glaucoma, 27 pseudoexfoliation syndrome and 61 control subjects were enrolled in the study. Patients with pseudoexfoliation syndrome and pseudoexfoliation glaucoma did not show any genetic association with either single-nucleotide polymorphism rs1048661 or rs3825942. CONCLUSION The study shows lack of association between LOXL1 single-nucleotide polymorphisms and pseudoexfoliation in North Indian population.
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Affiliation(s)
| | - Partha Chakma
- 1 Advanced Eye Centre, PGIMER, Chandigarh, Chandigarh, India
| | - Alka Khera
- 1 Advanced Eye Centre, PGIMER, Chandigarh, Chandigarh, India
| | - Neera Chugh
- 2 Department of Experimental Medicine & Biotechnology, PGIMER, Chandigarh, Chandigarh, India
| | | | | | | | - Srishti Raj
- 1 Advanced Eye Centre, PGIMER, Chandigarh, Chandigarh, India
| | | | - Madhu Khullar
- 2 Department of Experimental Medicine & Biotechnology, PGIMER, Chandigarh, Chandigarh, India
| | - Jagat Ram
- 1 Advanced Eye Centre, PGIMER, Chandigarh, Chandigarh, India
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Li H, He X, Peng Y, Shao B, Duan H, Yang F, Chen H, Lan Q. LOXL1 regulates cell apoptosis and migration in human neuroglioma U87 and U251 cells via Wnt/β-catenin signaling. Int J Clin Exp Pathol 2018; 11:2032-2037. [PMID: 31938310 PMCID: PMC6958203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 01/16/2018] [Indexed: 06/10/2023]
Abstract
The role of extracellular matrix proteins in glioma progression is largely unknown. In the current study, we screened different published GSE datasets and found that an extracellular matrix protein Lysyl Oxidase-Like 1 (LOXL1) is highly expressed in different cohorts of glioma patients. To confirm the results from datasets, we examined the level of LOXL1 in 30 matched glioma tissues and we found that LOXL1 is highly expressed in glioma malignant tissues. We further investigated the biological functions of LOXL1 in glioma cells with both loss- and gain-function assays. These show that highly expressed LOXL1 promotes glioma cell proliferation and growth through regulating Wnt/β-catenin signaling. In conclusion, we report that thesecretory protein LOXL1 is highly expressed in malignantglioma tissues and promotes glioma cell proliferation through Wnt/β-catenin signaling.
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Affiliation(s)
- Huiyong Li
- Department of Neurosurgery, Second Affiliated Hospital of Suchow UniversitySuzhou, China
- Department of Neurosurgery, The First Hospital of WenlingWenling, China
| | - Xijun He
- Department of Neurosurgery, The First Hospital of WenlingWenling, China
| | - Yujiang Peng
- Department of Neurosurgery, The First Hospital of WenlingWenling, China
| | - Bo Shao
- Department of Neurosurgery, The First Hospital of WenlingWenling, China
| | - Hongyu Duan
- Department of Neurosurgery, The First Hospital of WenlingWenling, China
| | - Fan Yang
- Department of Neurosurgery, The First Hospital of WenlingWenling, China
| | - Huihui Chen
- Department of Neurosurgery, The First Hospital of WenlingWenling, China
| | - Qing Lan
- Department of Neurosurgery, Second Affiliated Hospital of Suchow UniversitySuzhou, China
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Besiktepe N, Kayalar O, Ersen E, Oztay F. The copper dependent-lysyl oxidases contribute to the pathogenesis of pulmonary emphysema in chronic obstructive pulmonary disease patients. J Trace Elem Med Biol 2017; 44:247-255. [PMID: 28965583 DOI: 10.1016/j.jtemb.2017.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/15/2017] [Accepted: 08/17/2017] [Indexed: 02/05/2023]
Abstract
Abnormalities in the elastic fiber biology are seen in pulmonary emphysema (PE). The copper-dependent lysyl oxidases regulate the production and accumulation of elastic fibers in the connective tissue. This study focused on the relationship between lysyl oxidase (LOX), LOX-like protein 1 (LOXL1), and LOXL2 and PE pathogenesis. Lung samples with or without PE from patients with chronic obstructive lung disease (n=35) were used. Protein levels of elastin, LOX, LOXL1, LOXL2, hypoxia inducible factor 1-alpha (HIF-1α), copper metabolism domain containing-1 (COMMD1), and phosphatase and tensin homolog (PTEN) were assayed using microscopic and biochemical methods The emphysematous areas were characterized by enlargement of the alveoli, destruction of the alveolar structure, accumulation of macrophages in the alveolar lumens, and showed increased HIF-1α immunoreactivity. Additionally, the emphysematous areas had significantly lower elastin, LOX, LOXL1, LOXL2, HIF-1α, COMMD1, and PTEN protein levels than the non-emphysematous areas. We suppose that the reductions in the HIF-1α levels led to decreases in the protein levels of active LOX, LOXL1, and LOXL2. These decreases might cause abnormalities in the elastic fiber biology. HIF-1α activation induced by decreased COMMD1 and protease activation induced by decreased PTEN might contribute to the development of PE. Finally, methods aimed at increasing the protein levels of LOXs, COMMD1 and PTEN might be effective for treating PE.
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Affiliation(s)
- Neziha Besiktepe
- Department of Biology, Faculty of Science, Istanbul University, 34134 Vezneciler, Istanbul, Turkey.
| | - Ozgecan Kayalar
- Department of Biology, Faculty of Science, Istanbul University, 34134 Vezneciler, Istanbul, Turkey.
| | - Ezel Ersen
- Department of Thoracic Surgery, Cerrahpasa Medical Faculty, Istanbul University, 34098 Kocamustafapasa, Istanbul, Turkey.
| | - Fusun Oztay
- Department of Biology, Faculty of Science, Istanbul University, 34134 Vezneciler, Istanbul, Turkey.
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22
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Papadopoulou M, Papadaki H, Zolota V, Gartaganis SP. Immunohistochemical Profiles of LOXL-1, FBN1, TGF-β1, and COX-2 in Pseudoexfoliation Syndrome. Curr Eye Res 2017; 42:880-889. [PMID: 28085506 DOI: 10.1080/02713683.2016.1257726] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSES To (i) determine expression patterns of lysyl oxidase-like 1 (LOXL1), fibrillin-1 (FBN1), transforming growth factor beta-1 (TGF-β1), and cyclooxygenase-2 (COX-2) in lens epithelium and anterior lens capsule in pseudoexfoliation (PEX) syndrome and (ii) delineate the roles of these proteins in the etiopathogenesis of PEX. MATERIALS AND METHODS Study participants, all of whom had undergone cataract surgery, comprised 47 patients with and 27 patients without (controls) PEX syndrome. Immunohistochemistry on paraffin sections of lens capsule and lens epithelium was performed. RESULTS Immunoexpression of LOXL1 and FBN1 on the outer surface of the lens capsule was significantly higher (p < 0.001), and nuclear immunopositivity for LOXL1 was more frequently observed (p = 0.017), in PEX patients compared with control patients. Cytoplasmic expression of LOXL1 and COX-2 was significantly lower (p = 0.015 and p = 0.042, respectively) in PEX patients compared with controls. TGF-β1 exhibited diffuse immunostaining detected in all cell layers in PEX patients (p <0.001). Significant direct correlations of cytoplasmic LOXL1 with FBN1 and TGF-β1, and of COX-2 with FBN1, TGF-β1, and LOXL-1, were observed only in PEX patients. CONCLUSIONS Results of our study provide valuable information vis-à-vis expression and localization of TGF-β1, LOXL1, and FBN1, as well as their associations in the lens epithelium and lens capsule. These data not only advance our knowledge of the etiopathogenesis of PEX syndrome, but also include novel findings, for example, immunostaining patterns of TGF-β1 in PEX syndrome. We suggest that COX-2 plays a role in the pathobiology of PEX syndrome and should be the subject of future investigations.
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Affiliation(s)
- Margarita Papadopoulou
- a Department of Ophthalmology, School of Medicine , University of Patras , Rion , Greece.,b Department of Ophthalmology , University Hospital of Coventry and Warwickshire , UK
| | - Helen Papadaki
- c Department of Anatomy, School of Medicine , University of Patras , Rion , Greece
| | - Vasiliki Zolota
- d Department of Pathology, School of Medicine , University of Patras , Rion , Greece
| | - Sotirios P Gartaganis
- a Department of Ophthalmology, School of Medicine , University of Patras , Rion , Greece
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23
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Aboobakar IF, Johnson WM, Stamer WD, Hauser MA, Allingham RR. Major review: Exfoliation syndrome; advances in disease genetics, molecular biology, and epidemiology. Exp Eye Res 2016; 154:88-103. [PMID: 27845061 DOI: 10.1016/j.exer.2016.11.011] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/06/2016] [Accepted: 11/10/2016] [Indexed: 12/20/2022]
Abstract
Exfoliation syndrome (XFS) is a common age-related disorder that leads to deposition of extracellular fibrillar material throughout the body. The most recognized disease manifestation is exfoliation glaucoma (XFG), which is a common cause of blindness worldwide. Recent developments in XFS genetics, cell biology and epidemiology have greatly improved our understanding of the etiology of this complex inherited disease. This review summarizes current knowledge of XFS pathogenesis, identifies gaps in knowledge, and discusses areas for future research.
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Affiliation(s)
- Inas F Aboobakar
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - William M Johnson
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Michael A Hauser
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - R Rand Allingham
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA.
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24
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Pasquale LR, Borrás T, Fingert JH, Wiggs JL, Ritch R. Exfoliation syndrome: assembling the puzzle pieces. Acta Ophthalmol 2016; 94:e505-12. [PMID: 26648185 DOI: 10.1111/aos.12918] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 09/25/2015] [Indexed: 12/15/2022]
Abstract
PURPOSE To summarize various topics and the cutting edge approaches to refine XFS pathogenesis that were discussed at the 21st annual Glaucoma Foundation Think Tank meeting in New York City, Sept. 19-20, 2014. METHODS The highlights of three categories of talks on cutting edge research in the field were summarized. RESULTS Exfoliation syndrome (XFS) is a systemic disorder with a substantial ocular burden, including high rates of cataract, cataract surgery complications, glaucoma and retinal vein occlusion. New information about XFS is akin to puzzle pieces that do not quite join together to reveal a clear picture regarding how exfoliation material (XFM) forms. CONCLUSION Meeting participants concluded that it is unclear how the mild homocysteinemia seen in XFS might contribute to the disarrayed extracellular aggregates characteristic of this syndrome. Lysyl oxidase-like 1 (LOXL1) variants are unequivocally genetic risk factors for XFS but exactly how these variants contribute to the assembly of exfoliation material (XFM) remains unclear. Variants in a new genomic region, CACNA1A associated with XFS, may alter calcium concentrations at the cell surface and facilitate XFM formation but much more work is needed before we can place this new finding in proper context. It is hoped that various animal model and ex vivo systems will emerge that will allow for proper assembly of the puzzle pieces into a coherent picture of XFS pathogenesis. A clear understanding of XFS pathogenesis may lead to 'upstream solutions' to reduce the ocular morbidity produced by XFS.
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Affiliation(s)
- Louis R. Pasquale
- Department of Ophthalmology; Mass Eye & Ear Infirmary; Harvard Medical School; Boston Massachusetts USA
- Department of Medicine; Harvard Medical School; Brigham and Women's Hospital; Boston Massachusetts USA
| | - Terete Borrás
- Department of Ophthalmology; University of North Carolina; Chapel Hill North Carolina USA
| | - John H. Fingert
- Department of Ophthalmology and Visual Sciences; University of Iowa; Iowa City Iowa USA
| | - Janey L. Wiggs
- Department of Ophthalmology; Mass Eye & Ear Infirmary; Harvard Medical School; Boston Massachusetts USA
| | - Robert Ritch
- Einhorn Clinical Research Center; New York Eye and Ear Infirmary of Mount Sinai; New York City New York USA
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Sharma S, Martin S, Sykes MJ, Dave A, Hewitt AW, Burdon KP, Ronci M, Voelcker NH, Craig JE. Biological effect of LOXL1 coding variants associated with pseudoexfoliation syndrome. Exp Eye Res 2016; 146:212-23. [PMID: 26997634 DOI: 10.1016/j.exer.2016.03.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 03/01/2016] [Accepted: 03/13/2016] [Indexed: 01/08/2023]
Abstract
Pseudoexfoliation (PEX) syndrome is a systemic disease involving the extracellular matrix. It increases the risk of glaucoma, an irreversible cause of blindness, and susceptibility to heart disease, stroke and hearing loss. Single nucleotide polymorphisms (SNPs) in the LOXL1 (Lysyl oxidase-like 1) gene are the major known genetic risk factor for PEX syndrome. Two coding SNPs, rs1048861 (G > T; Arg141Leu) and rs3825942 (G > A; Gly153Asp), in the LOXL1 gene are strongly associated with the disease risk in multiple populations worldwide. In the present study, we investigated functional effects of these SNPs on the LOXL1 protein. We show through molecular modelling that positions 141 and 153 are likely surface residues and hence possible recognition sites for protein-protein interactions; the Arg141Leu and Gly153Asp substitutions cause charge changes that would lead to local differences in protein electrostatic potential and in turn the potential to modify protein-protein interactions. In RFL-6 rat fetal lung fibroblast cells ectopically expressing the LOXL1 protein variants related to PEX (Arg141_Gly153, Arg141_Asp153 or Leu141_Gly153), immunoprecipitation of the secreted variants showed differences in their processing by endogenous proteins, possibly Bone morphogenetic protein-1 (BMP-1) that cleaves and leads to enzymatic activation of LOXL1. Immunofluorescence labelling of the ectopically expressed protein variants in RFL-6 cells showed no significant difference in their extracellular accumulation tendency. In conclusion, this is the first report of a biological effect of the coding SNPs in the LOXL1 gene associated with PEX syndrome, on the LOXL1 protein. The findings indicate that the disease associated coding variants themselves may be involved in the manifestation of PEX syndrome.
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Abstract
Pseudoexfoliation syndrome (PXS) and pigment dispersion syndrome (PDS) are two of the commonest disorders to produce secondary open-angle glaucoma through trabecular meshwork blockage. Each is a defined clinical entity, and while genetics likely play a significant role in the pathogenesis of both, the specific genes involved appear to be distinct. There is surprisingly little published in the literature regarding the coexistence of PDS and PXS in the same patient. We present the intriguing case of a patient who developed PDS in one eye and PXS in the other. This unusual case acts as a platform for an interesting discussion of the genomics of PXS and PDS.
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Affiliation(s)
- Olya Pokrovskaya
- Department of Ophthalmology, Mater Misericordiae University Hospital, and School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland
| | - Colm O'Brien
- Department of Ophthalmology, Mater Misericordiae University Hospital, and School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland
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Founti P, Haidich AB, Chatzikyriakidou A, Salonikiou A, Anastasopoulos E, Pappas T, Lambropoulos A, Viswanathan AC, Topouzis F. Ethnicity-Based Differences in the Association of LOXL1 Polymorphisms with Pseudoexfoliation/Pseudoexfoliative Glaucoma: A Meta-Analysis. Ann Hum Genet 2015; 79:431-50. [PMID: 26404116 DOI: 10.1111/ahg.12128] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 07/05/2015] [Indexed: 01/09/2023]
Abstract
Pseudoexfoliation (PEX) is an age-related disorder of the extracellular matrix; it is strongly associated with glaucoma, the leading cause of irreversible blindness worldwide. We conducted an ethnic-based meta-analysis of the association of LOXL1 polymorphisms with PEX/pseudoexfoliative glaucoma (PEXG). Association studies were retrieved systematically from PubMed, EMBASE, and Web of Knowledge. Allelic and genotype frequencies of rs3825942, rs1048661, and rs2165241 were compared between PEX/PEXG and controls. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using a random effects model. Overall, 39 independent cohorts were included. Rs3825942 (G) was an at risk allele for PEX/PEXG in Caucasians, Japanese, Koreans, Chinese, South Asians, and Middle Easterners, but protective in Black South Africans (OR = 0.10, 95%CI:0.06-0.16). Rs1048661 (G) was an at risk allele for PEX/PEXG in Caucasians, South Asians, Middle Easterners and Black South Africans, but was protective in Japanese (OR = 0.03, 95%CI:0.02-0.06) and Koreans (OR = 0.10, 95%CI:0.05-0.22). These associations we-re confirmed for the genotypic recessive models. Rs2165241 (C) was a protective allele for PEX/PEXG in Caucasians, but was an at risk allele in Japanese (OR = 7.49, 95%CI:3.22-17.41) and Koreans (OR = 6.63, 95%CI:2.60-16.90). This was confirmed for the genotypic dominant model. Other genetic and/or environmental factors may modify the effect of LOXL1 polymorphisms in certain ethnic groups.
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Affiliation(s)
- Panayiota Founti
- Department of Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.,Moorfields Eye Hospital, London, UK
| | - Anna-Bettina Haidich
- Department of Hygiene and Epidemiology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Anthoula Chatzikyriakidou
- Department of Biology and Genetics, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Angeliki Salonikiou
- Department of Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Eleftherios Anastasopoulos
- Department of Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Theofanis Pappas
- Department of Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Alexandros Lambropoulos
- Department of Biology and Genetics, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Ananth C Viswanathan
- NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust, University College London, Institute of Ophthalmology, London, UK
| | - Fotis Topouzis
- Department of Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Tanito M, Hara K, Akahori M, Harata A, Itabashi T, Takai Y, Kaidzu S, Ohira A, Iwata T. Lack of association of LOXL1 gene variants in Japanese patients with central retinal vein occlusion without clinically detectable pseudoexfoliation material deposits. Acta Ophthalmol 2015; 93:e214-7. [PMID: 25130441 DOI: 10.1111/aos.12534] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 07/10/2014] [Indexed: 12/23/2022]
Abstract
PURPOSE A possible association has been reported between exfoliation syndrome (EX) and various ocular and systemic vascular disorders; however, it is unclear if there is an association between EX and central retinal vein occlusion (CRVO). Because latent deposits of exfoliation materials might not be recognized during slit-lamp examination, an ocular biopsy is required to establish a precise diagnosis. We evaluated a possible association between EX and CRVO using lysyl oxidase-like 1 (LOXL1) gene variants as alternative markers for EX. METHODS The allelic and genotypic frequencies of three LOXL1 variants (rs1048661, rs3825942, and rs2165241) were determined in 68 consecutive Japanese patients with CRVO [15 with exfoliation syndrome (EX+) and 53 without exfoliation syndrome (EX-)] and 90 control patients with cataract without EX (CT). RESULTS The frequencies of the rs1048661 and rs3825942 variants showed borderline difference between the CRVO and CT groups (p = 0.04085 and p = 0.06088, respectively, for allelic frequencies, and p = 0.06838 and p = 0.03482, respectively, for genotypic frequencies). Compared with the CT group, subgroup analysis showed that the CRVO EX+ group had significant differences in the allelic and genotypic frequencies of rs1048661 (p = 0.0006447 and p = 0.0001392, respectively) and had borderline differences in the allelic and genotypic frequencies of rs3825942 (p = 0.03403 and p = 0.07341, respectively), while the CRVO EX- group did not (p = 0.1324-0.6306). Subgroup analysis showed that the frequencies of rs2165241 did not differ between the CRVO and CT groups. CONCLUSIONS When the LOXL1 variants were used as disease markers for clinically undetectable EX, there was no association between CRVO and EX. The results suggested that the LOXL1 variants, which are well-established markers for EX, are not likely genetic markers for CRVO in Japanese subjects.
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Affiliation(s)
- Masaki Tanito
- Shimane University Faculty of Medicine Izumo Shimane Japan
- Division of Ophthalmology Matsue Red Cross Hospital Matsue Shimane Japan
| | - Katsunori Hara
- Shimane University Faculty of Medicine Izumo Shimane Japan
| | - Masakazu Akahori
- National Institute of Sensory Organs National Hospital Organization Tokyo Medical Center Tokyo Japan
| | - Ayano Harata
- National Institute of Sensory Organs National Hospital Organization Tokyo Medical Center Tokyo Japan
| | - Takeshi Itabashi
- National Institute of Sensory Organs National Hospital Organization Tokyo Medical Center Tokyo Japan
| | - Yasuyuki Takai
- Shimane University Faculty of Medicine Izumo Shimane Japan
| | - Sachiko Kaidzu
- Shimane University Faculty of Medicine Izumo Shimane Japan
| | - Akihiro Ohira
- Shimane University Faculty of Medicine Izumo Shimane Japan
| | - Takeshi Iwata
- National Institute of Sensory Organs National Hospital Organization Tokyo Medical Center Tokyo Japan
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29
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Anastasopoulos E, Coleman AL, Wilson MR, Sinsheimer JS, Yu F, Katafigiotis S, Founti P, Salonikiou A, Pappas T, Koskosas A, Katopodi T, Lambropoulos A, Topouzis F. Association of LOXL1 polymorphisms with pseudoexfoliation, glaucoma, intraocular pressure, and systemic diseases in a Greek population. The Thessaloniki eye study. Invest Ophthalmol Vis Sci 2014; 55:4238-43. [PMID: 24917141 DOI: 10.1167/iovs.14-13991] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
PURPOSE To investigate the association of the two single-nucleotide polymorphisms (SNPs) in the lysyl oxidase-like 1 (LOXL1) gene with pseudoexfoliation syndrome (PEX), pseudoexfoliative glaucoma (PEXG), and primary open-angle glaucoma (POAG) in a Greek population-based setting, from the Thessaloniki Eye study. METHODS A total of 233 subjects with successful DNA extraction, PCR amplification, and genotyping were included in the genetic analysis of G153D and R141L SNPs of LOXL1 gene and classified into four groups: controls (n = 93); subjects with PEX (n = 40); POAG (n = 66); and PEXG (n = 34). Multinomial logistic regression was used to test their association with LOXL1 SNPs with adjustment for covariates. The association of LOXL1 with IOP (in untreated subjects) and with systemic diseases was explored. RESULTS Both LOXL1 SNPs were present in high frequencies in controls and cases. The G153D was strongly associated with both PEX (odds ratio [OR] = 23.2, P = 0.003 for allele G) and PEXG (OR = 24.75, P = 0.003 for allele G) and was not associated with POAG (P = 0.451). In contrast, the R141L was not associated with PEX (P = 0.81), PEXG (P = 0.063), or POAG (P = 0.113). No association of the G153D with either intraocular pressure (IOP) or systemic diseases was found. CONCLUSIONS In the Thessaloniki Eye Study, the G153D SNP of LOXL1 gene was strongly associated with both PEX and PEXG, whereas the R141L was not associated. No association of the LOXL1 with IOP or with systemic diseases was found. These findings further support the hypothesis that the LOXL1 gene contributes to onset of PEXG through PEX. Gene variants of LOXL1 do not help to identify those with PEX at increased risk for glaucoma development.
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Affiliation(s)
- Eleftherios Anastasopoulos
- Department of Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Anne L Coleman
- Center for Eye Epidemiology, Jules Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States
| | - M Roy Wilson
- School of Medicine, Wayne State University, Detroit, Michigan, United States
| | - Janet S Sinsheimer
- Department of Human Genetics, Department of Biomathematics, David Geffen School of Medicine at UCLA and Department of Biostatistics, UCLA School of Public Health, California, United States
| | - Fei Yu
- Center for Eye Epidemiology, Jules Stein Eye Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States
| | - Sokratis Katafigiotis
- Laboratory of General Biology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Panayiota Founti
- Department of Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Angeliki Salonikiou
- Department of Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Theofanis Pappas
- Department of Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Archimidis Koskosas
- Department of Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Theodora Katopodi
- Laboratory of General Biology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Alexandros Lambropoulos
- Laboratory of General Biology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Fotis Topouzis
- Department of Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
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de Juan-Marcos L, Escudero-Domínguez FA, Hernández-Galilea E, Cabrillo-Estévez L, Cruz-González F, Cieza-Borrella C, Sánchez-Barba M, González-Sarmiento R. Association of Lysyl Oxidase-Like 1 Gene Polymorphisms in Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma in a Spanish Population. Ophthalmic Genet 2014; 37:25-30. [PMID: 24892565 DOI: 10.3109/13816810.2014.921316] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To evaluate the association of the lysyl oxidase-like 1 (LOXL1) single nucleotide polymorphisms (SNPs) in a Spanish population with pseudoexfoliation syndrome (XFS) and pseudoexfoliation glaucoma (XFG). MATERIALS AND METHODS The present case-control study included 100 Spanish patients (60 patients with XFS and 40 patients with XFG) and 90 control subjects. Genotypes of the three single nucleotide polymorphisms of LOXL1 (rs1048661, rs3825942, and rs2165241) were analyzed with direct sequencing. RESULTS The G allele and the GG genotype of SNP rs3825942 were detected at a statistically higher frequency in pseudoexfoliation patients than in control subjects (p = 3.36 × 10(-5), OR = 5.71, 95% CI: 2.30-14.18; p = 3.38 × 10(-5), OR = 6.91, 95% CI: 2.51-19.03 respectively). The T allele and the TT genotype of SNP rs2165241 presented at significantly higher frequencies in pseudoexfoliation patients than in controls (p = 2.50 × 10(-4), OR = 2.18, 95% CI: 1.43-3.33; p = 1.21 × 10(-2), OR = 2.13, 95% CI: 1.75-3.85 respectively). No significant association between XFS/XFG and the rs1048661 was observed. The GGT haplotype composed of all three risk alleles was determined to be significantly associated with pseudoexfoliation. The genotypic and allelic distributions of the three SNPs were similar between XFS and XFG. CONCLUSIONS This is the first study associating two SNPs of LOXL1 (rs3825942 and rs2165241) and XFS/XFG in a Spanish population, confirming findings in patients from Europe. However rs1048661 SNP did not show an association with XFS.
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Affiliation(s)
- Lourdes de Juan-Marcos
- a Department of Ophthalmology , University Hospital of Salamanca .,b Institute for Biomedical Research of Salamanca (IBSAL)
| | | | - Emiliano Hernández-Galilea
- a Department of Ophthalmology , University Hospital of Salamanca .,b Institute for Biomedical Research of Salamanca (IBSAL)
| | | | - Fernando Cruz-González
- a Department of Ophthalmology , University Hospital of Salamanca .,b Institute for Biomedical Research of Salamanca (IBSAL)
| | | | | | - Rogelio González-Sarmiento
- b Institute for Biomedical Research of Salamanca (IBSAL) .,c Molecular Medicine Unit, Department of Medicine , University of Salamanca .,e Institute of Molecular and Cellular Biology of Cancer (BMCC), University of Salamanca-CSIC , Salamanca , Spain
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Wiggs JL, Pawlyk B, Connolly E, Adamian M, Miller JW, Pasquale LR, Haddadin RI, Grosskreutz CL, Rhee DJ, Li T. Disruption of the blood-aqueous barrier and lens abnormalities in mice lacking lysyl oxidase-like 1 ( LOXL1). Invest Ophthalmol Vis Sci 2014; 55:856-64. [PMID: 24425853 DOI: 10.1167/iovs.13-13033] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Exfoliation syndrome (ES) is commonly associated with glaucoma, premature cataracts, and other ocular and systemic pathologies. LOXL1 gene variants are significantly associated with ES; however, the role of the protein in ES development remains unclear. The purpose of this study was to characterize the ocular phenotype in Loxl1(-/-) (null) mice. METHODS Loxl1 null mice and strain-matched controls (C57BL) were evaluated by clinical and histologic analyses. RESULTS Anterior segment histology showed a pronounced vesiculation of the anterior lens in the null mice. The lesions were subcapsular and in direct apposition with the posterior iris surface. Fluorescein angiography showed increased diffusion of fluorescein into the anterior chamber of the null mice compared with age-matched controls (P = 0.003, two-tailed, unequal variance t-test), suggesting compromise of the blood-aqueous barrier. Intraocular pressure measurements were within the normal range (16.5 ± 2.0 mm Hg) in null mice up to 1 year of age. Immunohistochemistry showed decreased elastin in the iris and ciliary body in the null mouse compared with controls. CONCLUSIONS Elimination of LOXL1 in mice impairs the blood-aqueous humor barrier in the ocular anterior segment and causes lens abnormalities consistent with cataract formation, but does not result in deposition of macromolecular material or glaucoma. These results show that mice lacking LOXL1 have some ES features but that complete disease manifestation requires other factors that could be genetic and/or environmental.
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Affiliation(s)
- Janey L Wiggs
- Department of Ophthalmology, Harvard Medical School, Howe, Berman Gund and Angiogenesis Laboratories, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
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Whigham BT, Allingham RR. Review: The role of LOXL1 in exfoliation syndrome/glaucoma. Saudi J Ophthalmol 2011; 25:347-52. [PMID: 23960948 DOI: 10.1016/j.sjopt.2011.07.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 07/14/2011] [Accepted: 07/18/2011] [Indexed: 11/27/2022] Open
Abstract
Exfoliation syndrome is a common cause of open-angle glaucoma. It is characterized by microscopic flakes of protein-rich material being deposited in both ocular and non-ocular tissues. While its mechanism is poorly understood, family- and population-based studies have established that the disorder has a strong genetic component. A further understanding of the relevant gene variants might help reveal the molecular mechanism behind exfoliation. The most-strongly associated genetic variants are found in the lysyl oxidase-like 1 (LOXL1) gene. However, two major risk alleles in the LOXL1 coding region are reversed between ethnic groups. It now appears the strong association between LOXL1 and XFS is due to non-coding variants that have not yet been identified. Such variants might alter LOXL1 expression, which is decreased in the late stages of exfoliation syndrome/glaucoma. Here we discuss LOXL1 as a risk gene for exfoliation syndrome and glaucoma.
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Affiliation(s)
- Benjamin T Whigham
- Center for Human Genetics, Duke University Medical Center, Durham, NC, USA
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Abstract
Pseudoexfoliation (PEX) syndrome, one of the most common causes of glaucoma, represents a complex, multifactorial, late-onset disease of worldwide significance. The etiopathogenesis involves both genetic and non-genetic factors. The PEX-specific tissue alterations are caused by a generalized fibrotic matrix process, which has been characterized as a stress-induced elastosis associated with the excessive production and abnormal cross-linking of elastic microfibrils into fibrillar PEX aggregates. The identification of lysyl oxidase-like 1 (LOXL1) as a major genetic risk factor for PEX syndrome and PEX glaucoma further supports a role of elastogenesis and elastosis in the pathophysiology of PEX, as LOXL1 is a pivotal cross-linking enzyme in elastic fiber formation and stabilization. The available data suggest that LOXL1 is markedly dysregulated depending on the stage of the fibrotic process. While transient upregulation of LOXL1 during the early stages of PEX fibrogenesis participates in the formation and aggregation of abnormal PEX fiber deposits, the decreased expression of LOXL1 during the advanced stages of the disease may affect elastin metabolism and promote elastotic processes, e.g. in the lamina cribrosa, predisposing to glaucoma development. However, in view of the low penetrance of the PEX-associated risk variants of LOXL1, other genetic and/or environmental factors must contribute to the risk of developing the PEX phenotype. Some evidence exists for the contribution of additional genes with relatively small effects, e.g. clusterin (CLU), contactin-associated protein-like 2 (CNTNAP2), apolipoprotein E (APOE), glutathione S-transferases (GSTs), and tumor necrosis factor-alpha (TNFA), in certain study populations. Several environmental conditions associated with PEX, such as oxidative stress as well as pro-fibrotic cytokines and growth factors, can regulate expression of LOXL1 and elastic proteins in vitro and may therefore act as co-modulating external factors. Ultimately, both detection and functional characterization of yet unidentified genetic and non-genetic factors may lead to the development of more precise screening tools for the risk of PEX glaucoma.
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