title: ARMS2 interference leads to decrease of proinflammatory  mediators.
abstract: BACKGROUND
  Age-related macular degeneration (AMD) is a major cause of irreversible blindness among elderly people in developed countries. Many studies suggested that age-related maculopathy susceptibility 2 (ARMS2) is the second major susceptibility gene for AMD. Increasing evidence was found recently that inflammatory processes and oxidative stress may contribute to the pathogenesis of AMD. Meanwhile, the mechanisms underlying the contributions of ARMS2 to the pathogenesis of AMD remain unclear. The purpose of the current study was to elucidate the relationship between the ARMS2 gene and proinflammatory mediators, for further assessment of the associated biologic effects.
  
  
  METHODS
  siRNA was used to knock down ARMS2 mRNA, and Western blotting and reverse real-time PCR were used to detect the effect of siRNA on the expression of ARMS2 in ARPE-19 cells. The expressions of C3, C5, IL-6, IL-8, and TNF-α after si-RNA knockdown were evaluated by SYBR Green I real-time PCR and ELISA.
  
  
  RESULTS
  Transcription accumulative indexes (TAI = 2(-delta delta CT)) of ARMS2 by real-time PCR revealed that the transfection rate in the positive control group was 72.0 ± 2.07 % (P < 0.01). The ratio of absorbance values (by Western blotting) of AMRS2 to β-actin was 0.85 ± 0.122, 0.87 ± 0.143, and 0.61 ± 0.240 in the blank control group, scrambled ARMS2-siRNA group, and ARMS2-siRNA group respectively (F = 42.5, P < 0.01). The secreted protein levels of C3, C5, IL-6, IL-8, and TNF-α were found by ELISA to be reduced by 34.24 ± 1.81 %, 37.15 ± 2.02 %, 35.11 ± 1.75 %, 30.11 ± 2.19 %, and 34.33 ± 2.18 % respectively, in the siRNA-ARMS2 group (P < 0.05). Compared with the blank control group, reduced TAI of C3, C5, IL-6, IL-8, and TNF-α were detected by real-time PCR in the ARMS2-siRNA group.
  
  
  CONCLUSIONS
  This study produced evidence supporting the notion that the ARMS2 risk allele for AMD is linked directly or indirectly to proinflammatory mediators. More importantly, our data indicate that the change in ARMS2 may affect C3, C5, IL-6, IL-8, and TNF-α levels, and this may be one of the mechanisms of AMD development.
authors: Fanxing
authors: F
authors: Zeng
authors: Min
authors: M
authors: Zhang
authors: Yiting
authors: Y
authors: Xu
authors: Haifeng
authors: H
authors: Xu
mesh_terms: D000483:Alleles; D015153:Blotting, Western; D002460:Cell Line; D003176:Complement C3 / Q000378:metabolism; D003182:Complement C5 / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation / Q000502:physiology*; D055785:Gene Knockdown Techniques; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D008268:Macular Degeneration / Q000235:genetics* / Q000378:metabolism; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D055213:Retinal Pigment Epithelium / Q000378:metabolism*; D014162:Transfection
chemical_list: C514392:ARMS2 protein, human; D003176:Complement C3; D003182:Complement C5; D016207:Cytokines; D018836:Inflammation Mediators; D011506:Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering
references: Am J Ophthalmol. 2004 Mar;137(3):486-95
references: 15013873
references: Ophthalmology. 2010 Mar;117(3):500-11
references: 20022638
references: PLoS Genet. 2010 Feb 05;6(2):e1000836
references: 20140183
references: N Engl J Med. 2007 Aug 9;357(6):553-61
references: 17634448
references: Hum Mol Genet. 2005 Nov 1;14(21):3227-36
references: 16174643
references: Br J Ophthalmol. 2001 Oct;85(10):1153-7
references: 11567955
references: Science. 2006 Nov 10;314(5801):992-3
references: 17053109
references: Am J Hum Genet. 2005 Sep;77(3):389-407
references: 16080115
references: Invest Ophthalmol Vis Sci. 2009 Jul;50(7):3084-90
references: 19255159
references: N Engl J Med. 2008 Jun 12;358(24):2606-17
references: 18550876
references: Vision Res. 2008 Feb;48(5):690-4
references: 18206206
references: Surv Ophthalmol. 2006 Mar-Apr;51(2):137-52
references: 16500214
references: Surv Ophthalmol. 2003 May-Jun;48(3):257-93
references: 12745003
references: J Leukoc Biol. 2012 Feb;91(2):267-73
references: 22045869
references: Mol Vis. 2010 Dec 31;16:2923-30
references: 21203342
references: Mol Vis. 2010 Jul 15;16:1317-23
references: 20664794
references: Proc Natl Acad Sci U S A. 2007 Oct 9;104(41):16227-32
references: 17884985
references: Nat Genet. 2008 Jul;40(7):892-6
references: 18511946
references: Science. 2005 Apr 15;308(5720):419-21
references: 15761120
references: Arch Ophthalmol. 2005 Jun;123(6):774-82
references: 15955978
references: Science. 2005 Apr 15;308(5720):385-9
references: 15761122
references: Int J Ophthalmol. 2012;5(2):125-32
references: 22762035
references: PLoS One. 2012;7(7):e39890
references: 22802947
references: Hum Genet. 2010 Mar;127(5):595-602
references: 20182747
references: Nat Med. 2008 Feb;14(2):194-8
references: 18223656
references: Mol Vis. 2011 Apr 20;17:977-82
references: 21541271
references: Ophthalmology. 2007 Sep;114(9):1722-7
references: 17400294
references: Nat Genet. 2006 Apr;38(4):458-62
references: 16518403
references: Mol Immunol. 2013 Jun;54(2):122-31
references: 23267850
references: Science. 2005 Apr 15;308(5720):421-4
references: 15761121
references: Science. 2006 Nov 10;314(5801):989-92
references: 17053108
references: Clin Exp Ophthalmol. 2008 Jul;36(5):437-42
references: 18939352