title: Regulated expression of caspase-12 gene in human retinal pigment epithelial cells suggests its immunomodulating role.
abstract: OBJECTIVE
  To investigate the expression and regulation of the short form of caspase-12, caspase-12S, in human retinal pigment epithelial (hRPE) cells.
  
  
  METHODS
  hRPE cells were stimulated by the proinflammatory agents IL-1beta (2 ng/mL) and TNF-alpha (20 ng/mL); LPS (1000 ng/mL); coculture with monocytes; the immunomodulating agent cyclosporine (Cys; 30 ng/mL); the anti-inflammatory cytokine IL-10 (100 U/mL); and the endoplasmic reticulum (ER) stress inducers tunicamycin (3 or 10 muM) and thapsigargin (25 or 100 nM) for 6 hours or longer. The total RNAs were isolated and subjected to semiquantitative and quantitative real-time RT-PCR analysis. Effects of tunicamycin and thapsigargin on IL-1beta- and TNF-alpha-stimulated MCP-1 mRNA expression and protein production were further examined by RT-PCR and ELISA, respectively.
  
  
  RESULTS
  RT-PCR results showed that caspase-12S is the predominant form of caspase-12 in the examined hRPE cells of this study, with expression at levels as high as those in many other human tissues such as pancreas, prostate, small intestine, lung, spleen, and kidney. Treatment with IL-1beta and TNF-alpha, as well as LPS and coculture with monocytes reduced hRPE caspase-12S mRNA expression within 6 hours. In contrast, hRPE exposure to cyclosporine (Cys) and the cytokine IL-10 for 6 hours increased caspase-12S mRNA expression. Compared to Cys and IL-10, the ER stress activators tunicamycin and thapsigargin were even more potent enhancers of hRPE caspase-12S gene expression. They also caused corresponding reductions in IL-1beta- and TNF-alpha-induced MCP-1 mRNA expression and protein production.
  
  
  CONCLUSIONS
  hRPE cells express a high level of caspase-12S. The regulated expression of caspase-12S suggests that this caspase recruitment domain (CARD)-only protein may be an endogenous dominant negative regulator that modulates inflammatory responses in hRPE cells.
authors.affiliation: Department of Ophthalmology, University of Michigan, Ann Arbor, Michigan 48105, USA.
authors.forename: Zong-Mei
authors.initials: ZM
authors.lastname: Bian
authors.forename: Susan G
authors.initials: SG
authors.lastname: Elner
authors.forename: Victor M
authors.initials: VM
authors.lastname: Elner
mesh_terms: D017209:Apoptosis; D053454:Caspase 12 / Q000235:genetics*; D002470:Cell Survival; D002478:Cells, Cultured; D018920:Coculture Techniques; D016572:Cyclosporine / Q000494:pharmacology; D015536:Down-Regulation; D004797:Enzyme-Linked Immunosorbent Assay; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D006801:Humans; D016753:Interleukin-10 / Q000494:pharmacology; D053583:Interleukin-1beta / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D009000:Monocytes / Q000166:cytology; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019284:Thapsigargin / Q000494:pharmacology; D014018:Tissue Distribution; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D014415:Tunicamycin; D016753:Interleukin-10; D019284:Thapsigargin; D016572:Cyclosporine; C506444:CASP12 protein, human; D053454:Caspase 12
references.citation: J Cell Biol. 2003 Aug 4;162(3):457-67
references.pmid: 12885762
references.citation: Proc Natl Acad Sci U S A. 2008 Mar 18;105(11):4133-8
references.pmid: 18332441
references.citation: Mol Cell Biol. 2006 Apr;26(8):3071-84
references.pmid: 16581782
references.citation: FEBS Lett. 1997 Feb 10;403(1):61-9
references.pmid: 9038361
references.citation: Invest Ophthalmol Vis Sci. 2004 Jun;45(6):1887-96
references.pmid: 15161854
references.citation: J Immunol. 2007 Dec 15;179(12):7993-8
references.pmid: 18056338
references.citation: J Chem Neuroanat. 2004 Sep;28(1-2):101-5
references.pmid: 15363495
references.citation: Nature. 2000 Jan 6;403(6765):98-103
references.pmid: 10638761
references.citation: Mol Biotechnol. 2006 Oct;34(2):279-90
references.pmid: 17172673
references.citation: Life Sci. 2006 Aug 1;79(10):934-40
references.pmid: 16780893
references.citation: J Biol Chem. 2004 Dec 10;279(50):51729-38
references.pmid: 15383541
references.citation: Scand J Gastroenterol. 2007 Mar;42(3):416-7
references.pmid: 17354126
references.citation: Invest Ophthalmol Vis Sci. 2003 May;44(5):2184-91
references.pmid: 12714660
references.citation: Brain Res. 2006 Apr 21;1084(1):146-57
references.pmid: 16600192
references.citation: Cell Death Differ. 2007 Jan;14(1):23-31
references.pmid: 16977333
references.citation: Br J Ophthalmol. 2006 Jan;90(1):103-8
references.pmid: 16361678
references.citation: EMBO Rep. 2002 Jul;3(7):616-21
references.pmid: 12101092
references.citation: Cell Death Differ. 2004 Apr;11(4):365-8
references.pmid: 14685161
references.citation: Exp Eye Res. 2001 Jul;73(1):111-21
references.pmid: 11428868
references.citation: Ophthalmology. 1992 Sep;99(9):1364-7
references.pmid: 1407970
references.citation: Invest Ophthalmol Vis Sci. 2007 Mar;48(3):1362-7
references.pmid: 17325185
references.citation: Hum Mutat. 2006 Sep;27(9):975
references.pmid: 16917906
references.citation: Graefes Arch Clin Exp Ophthalmol. 2006 Oct;244(10):1322-8
references.pmid: 16544114
references.citation: Nature. 2006 Apr 20;440(7087):1064-8
references.pmid: 16625199
references.citation: Biochem Biophys Res Commun. 2008 Jan 4;365(1):47-53
references.pmid: 17971294
references.citation: Proc Natl Acad Sci U S A. 2006 Feb 28;103(9):3280-5
references.pmid: 16492792
references.citation: Curr Eye Res. 1997 Jun;16(6):547-55
references.pmid: 9192163
references.citation: Nature. 2004 May 6;429(6987):75-9
references.pmid: 15129283
references.citation: Invest Ophthalmol Vis Sci. 2006 Dec;47(12):5569-75
references.pmid: 17122150
references.citation: Exp Eye Res. 2003 May;76(5):573-83
references.pmid: 12697421
references.citation: Cell Death Differ. 2001 Jun;8(6):649-57
references.pmid: 11536016
references.citation: Nature. 2004 May 6;429(6987):35-7
references.pmid: 15129268
references.citation: Am J Pathol. 1990 Apr;136(4):745-50
references.pmid: 2183623
references.citation: Exp Eye Res. 2006 Sep;83(3):508-16
references.pmid: 16643900
references.citation: Cell Host Microbe. 2008 Mar 13;3(3):146-57
references.pmid: 18329614
references.citation: Invest Ophthalmol Vis Sci. 1997 Feb;38(2):436-45
references.pmid: 9040477
references.citation: Lab Invest. 1992 Feb;66(2):200-11
references.pmid: 1346541
references.citation: Am J Hum Genet. 2006 Apr;78(4):659-70
references.pmid: 16532395
references.citation: Cell Death Differ. 2007 Jan;14(1):10-22
references.pmid: 16977329
references.citation: Am J Ophthalmol. 1991 Dec 15;112(6):647-56
references.pmid: 1957899
references.citation: Proc Natl Acad Sci U S A. 2006 Nov 14;103(46):17366-71
references.pmid: 17088543
references.citation: Lab Invest. 1991 Jun;64(6):819-25
references.pmid: 2046333
references.citation: Invest Ophthalmol Vis Sci. 2008 Oct;49(10):4361-9
references.pmid: 18515575
references.citation: Curr Eye Res. 2006 Nov;31(11):947-53
references.pmid: 17114120
references.citation: J Biol Chem. 2004 Sep 17;279(38):39268-78
references.pmid: 15210718
references.citation: Invest Ophthalmol Vis Sci. 2008 Nov;49(11):5111-7
references.pmid: 18586875
references.citation: Am J Physiol Endocrinol Metab. 2004 Dec;287(6):E1171-7
references.pmid: 15315910
references.citation: J Biol Chem. 2001 Sep 14;276(37):34495-500
references.pmid: 11432859
references.citation: Invest Ophthalmol Vis Sci. 2007 Nov;48(11):5191-8
references.pmid: 17962473
references.citation: Biol Pharm Bull. 2003 Jul;26(7):931-5
references.pmid: 12843613
references.citation: Ann N Y Acad Sci. 2003 Dec;1010:186-94
references.pmid: 15033718
references.citation: J Immunol. 2006 Oct 1;177(7):4239-45
references.pmid: 16982854
references.citation: Nat Immunol. 2004 Jun;5(6):563-4
references.pmid: 15164013
references.citation: Biochem Biophys Res Commun. 2002 May 3;293(2):722-6
references.pmid: 12054529
references.citation: Biochem Biophys Res Commun. 2007 Aug 24;360(2):470-5
references.pmid: 17604001