title: Neurodegenerative and inflammatory pathway components linked to TNF-α/TNFR1 signaling in the glaucomatous human retina.
abstract: OBJECTIVE
  This study aimed to determine retinal proteomic alterations in human glaucoma, with particular focus on links to TNF-α/TNFR1 signaling.
  
  
  METHODS
  Human retinal protein samples were obtained from 20 donors with (n = 10) or without (n = 10) glaucoma. Alterations in protein expression were individually analyzed by quantitative LC-MS/MS. Quantitative Western blot analysis with cleavage or phosphorylation site-specific antibodies was used for data validation, and cellular localization of selected proteins was determined by immunohistochemical analysis of the retina in an additional group of glaucomatous human donor eyes (n = 38) and nonglaucomatous controls (n = 30).
  
  
  RESULTS
  Upregulated retinal proteins in human glaucoma included a number of downstream adaptor/interacting proteins and protein kinases involved in TNF-α/TNFR1 signaling. Bioinformatic analysis of the high-throughput data established extended networks of diverse functional interactions with death-promoting and survival-promoting pathways and mediation of immune response. Upregulated pathways included death receptor-mediated caspase cascade, mitochondrial dysfunction, endoplasmic reticulum stress, calpains leading to apoptotic cell death, NF-κB and JAK/STAT pathways, and inflammasome-assembly mediating inflammation. Interestingly, retinal expression pattern of a regulator molecule, TNFAIP3, exhibited prominent variability between individual samples, and methylation of cytosine nucleotides in the TNFAIP3 promoter was found to be correlated with this variability among glaucomatous donors.
  
  
  CONCLUSIONS
  Findings of this study reveal a number of proteins upregulated in the glaucomatous human retina that exhibit many links to TNF-α/TNFR1 signaling. By highlighting various signaling molecules and regulators involved in cell death and immune response pathways and by correlating proteomic findings with epigenetic alterations, these findings provide a framework motivating further research.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA.
authors.forename: Xiangjun
authors.initials: X
authors.lastname: Yang
authors.forename: Cheng
authors.initials: C
authors.lastname: Luo
authors.forename: Jian
authors.initials: J
authors.lastname: Cai
authors.forename: David W
authors.initials: DW
authors.lastname: Powell
authors.forename: Dahai
authors.initials: D
authors.lastname: Yu
authors.forename: Markus H
authors.initials: MH
authors.lastname: Kuehn
authors.forename: Gülgün
authors.initials: G
authors.lastname: Tezel
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D002853:Chromatography, Liquid; D019295:Computational Biology; D019175:DNA Methylation; D017931:DNA Primers; D005136:Eye Proteins / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D005901:Glaucoma / Q000378:metabolism*; D006801:Humans; D053612:Janus Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009410:Nerve Degeneration / Q000378:metabolism*; D009901:Optic Nerve Diseases / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D040901:Proteomics; D053218:Receptors, Death Domain / Q000378:metabolism; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism*; D012160:Retina / Q000378:metabolism*; D050791:STAT Transcription Factors / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D053719:Tandem Mass Spectrometry; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D017931:DNA Primers; D005136:Eye Proteins; D016328:NF-kappa B; D053218:Receptors, Death Domain; D047888:Receptors, Tumor Necrosis Factor, Type I; D050791:STAT Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D053612:Janus Kinases; D020169:Caspases