title: Inhibition of spermidine/spermine N1-acetyltransferase activity: a new therapeutic concept in rheumatoid arthritis.
abstract: OBJECTIVE
  Changes in polyamine-modulated factor 1 (PMF-1) promoter methylation might favor the expression of spermidine/spermine N1-acetyltransferase 1 (SSAT-1), causing excessive consumption of S-adenosyl methionine (SAM). This study was undertaken to evaluate the effect of SSAT-1 activity inhibition, either alone or in combination with SAM.
  
  
  METHODS
  Synovial fibroblasts were isolated from patients with rheumatoid arthritis (RA) or osteoarthritis (OA). PMF-1 promoter methylation was determined by pyrosequencing. Small interfering RNAs (siRNAs) against SSAT-1 were transfected weekly in RA synovial fibroblasts (RASFs). In addition, synovial fibroblasts were treated with diminazene aceturate (DA), an inhibitor of SSAT-1. SSAT-1, 5-methylcytosine (5-MeC), adenosyl methionine decarboxylase (AMD), PMF-1, DNA methyltransferase 1 (DNMT-1), CXCL12, β1 integrin, and CD44 levels were measured by flow cytometry. Putrescine levels were determined by colorimetry. Levels of matrix metalloproteinases were measured by enzyme-linked immunosorbent assay. Cell adhesion was tested. The SCID mouse model of RA was used to monitor the invasiveness of RASFs.
  
  
  RESULTS
  RASFs showed elevated SSAT-1, AMD, and PMF-1 levels. However, PMF-1 promoter methylation was unchanged. Transfection of siRNA targeting SSAT-1 increased 5-MeC levels within 21 days. Similarly, DA increased 5-MeC levels in RASFs. In addition, DA increased the levels of DNMT-1, decreased the levels of AMD, putrescine, activation markers, and MMP-1, and altered the adhesion of RASFs. DA was more efficient in RASFs with higher levels of SSAT-1. Most interestingly, the combination of DA and SAM reduced the invasiveness of RASFs by 70%.
  
  
  CONCLUSIONS
  The use of DA alone or in combination with SAM/L-methionine might introduce a new therapeutic concept in RA. This is the first therapy that would directly target RASFs and thereby inhibit ongoing joint destruction.
authors.affiliation: Zurich Center of Integrative Human Physiology, Center of Experimental Rheumatology, and University Hospital Zurich, Zurich, Switzerland.
authors.forename: Michel
authors.initials: M
authors.lastname: Neidhart
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Karouzakis
authors.forename: Astrid
authors.initials: A
authors.lastname: Jüngel
authors.forename: Renate E
authors.initials: RE
authors.lastname: Gay
authors.forename: Steffen
authors.initials: S
authors.lastname: Gay
mesh_terms: D000123:Acetyltransferases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D012437:Adenosylmethionine Decarboxylase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000368:Aged; D000818:Animals; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000378:metabolism*; D002478:Cells, Cultured; D019175:DNA Methylation / Q000502:physiology; D004133:Diminazene / Q000031:analogs & derivatives / Q000494:pharmacology; D015195:Drug Design; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D006801:Humans; D008297:Male; D051379:Mice; D016513:Mice, SCID; D008875:Middle Aged; D011401:Promoter Regions, Genetic / Q000502:physiology; D034741:RNA, Small Interfering / Q000494:pharmacology; D012436:S-Adenosylmethionine / Q000378:metabolism; D013583:Synovial Membrane / Q000166:cytology; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000099228:Diamine N-Acetyltransferase
chemical_list: D000123:Acetyltransferases; D012437:Adenosylmethionine Decarboxylase; D004133:Diminazene; D004791:Enzyme Inhibitors; D034741:RNA, Small Interfering; D012436:S-Adenosylmethionine; D014157:Transcription Factors; D000099228:Diamine N-Acetyltransferase; C120655:PMF1 protein, human; C003915:diminazene aceturate