Binding of Gtf2i-β/δ transcription factors to the ARMS2 gene leads to increased circulating HTRA1 in AMD patients and in vitro.

Abstract

The disease-initiating molecular events for age-related macular degeneration (AMD), a multifactorial retinal disease affecting many millions of elderly individuals worldwide, are still unknown. Of the over 30 risk and protective loci so far associated with AMD through whole genome-wide association studies (GWAS), the Age-Related Maculopathy Susceptibility 2 (ARMS2) gene locus represents one of the most highly associated risk regions for AMD. A unique insertion/deletion (in/del) sequence located immediately upstream of the High Temperature Requirement A1 (HTRA1) gene in this region confers high risk for AMD. Using electrophoretic mobility shift assay (EMSA), we identified that two Gtf2i-β/δ transcription factor isoforms bind to the cis-element 5'- ATTAATAACC-3' contained in this in/del sequence. The binding of these transcription factors leads to enhanced upregulation of transcription of the secretory serine protease HTRA1 in transfected cells and AMD patient-derived induced pluripotent stem cells (iPSCs). Overexpression of Htra1 in mice using a CAG-promoter demonstrated increased blood concentration of Htra1 protein, caused upregulation of vascular endothelial growth factor (VEGF), and produced a choroidal neovascularization (CNV)-like phenotype. Finally, a comparison of 478 AMD patients to 481 healthy, age-matched controls from Japan, India, Australia, and the USA showed a statistically increased level of secreted HTRA1 blood concentration in AMD patients compared with age-matched controls. Taken together, these results suggest a common mechanism across ethnicities whereby increased systemic blood circulation of secreted serine protease HTRA1 leads to subsequent degradation of Bruch's membrane and eventual CNV in AMD.

• Authors: Yang Pan, Daisuke Iejima, Mao Nakayama, Akiko Suga, Toru Noda, Inderjeet Kaur, Taraprasad Das, Subhabrata Chakrabarti, Robyn H Guymer, Margaret M DeAngelis, Megumi Yamamoto, Paul N Baird, Takeshi Iwata
• Journal: The Journal of biological chemistry (J Biol Chem) 2021 Jan-Jun Vol. 296 Pg. 100456 ISSN: 1083-351X [Electronic] United States
• PMID: 33636181 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.

Chemical References

• ARMS2 protein, human
• GTF2I protein, human
• Gtf2i protein, mouse
• Protein Isoforms
• Proteins
• Transcription Factors, TFII
• Transcription Factors, TFIII
• High-Temperature Requirement A Serine Peptidase 1
• HTRA1 protein, human
• HtrA1 protein, mouse

Topics

• Aged
• Aged, 80 and over
• Animals
• Female
• High-Temperature Requirement A Serine Peptidase 1 (genetics, metabolism)
• Humans
• INDEL Mutation (genetics)
• Macular Degeneration (genetics, physiopathology)
• Male
• Mice
• Mice, Transgenic
• Middle Aged
• Polymorphism, Single Nucleotide (genetics)
• Promoter Regions, Genetic (genetics)
• Protein Isoforms (genetics)
• Proteins (genetics, metabolism)
• Transcription Factors, TFII (genetics, metabolism)
• Transcription Factors, TFIII (genetics, metabolism)