title: Therapeutic effect of daphnetin on the autoimmune arthritis through demethylation of proapoptotic genes in synovial cells.
abstract: BACKGROUND
  We have previously reported that dephnetin is therapeutically effective in the treatment of rheumatoid arthritis (RA) in collagen-induced arthritis (CIA) rat model. However, the molecular mechanism and the effect of daphnetin on demethylating proapoptotic genes in the synovial cells remains further clarified. This study may provide a deeper insight into the medicinal application of daphnetin as a treatment for RA.
  
  
  METHODS
  (1) The proliferation inhibition of CIA rat synovial cells was determined by an MTT (3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenyterazoliumromide) assay; (2) Methylation specific PCR (MSP) was used to measure the methylation of the proapoptotic genes DR3 (death receptor 3), PDCD5 (programmed cell death 5), FasL and p53; (3) Real time-PCR was performed to determine the mRNA expression of DR3, PDCD5, FasL, p53 and DNA methyltransferases (DNMTs) DNMT1, DNMT3a and DNMT3b; (4) Flow cytometry was applied to detect the protein expression of the DR3, PDCD5, FasL and p53; (5) The apoptotic rate of synovial cells was assessed by flow cytometry with Annexin V and propidium iodide (PI); (6) Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the changes of CIA rat synovial cell structure.
  
  
  RESULTS
  (1) In the range of 1.25 μg/mL to 40 μg/mL, daphnetin and 5-aza-dc had a dose-dependent and time-dependent degree of inhibition to the CIA rat synovial cells. (2) Daphnetin and 5-aza-dc had a demethylating role on the proapoptotic genes DR3, PDCD5, FasL and p53 of CIA rat synovial cells. (3) Daphnetin and 5-aza-dc decreased the gene expression of methyltransferases DNMT1, DNMT3a and DNMT3b, and increased expression of proapoptotic genes DR3, PDCD5, FasL and p53, which translated into an increased protein expression of DR3, PDCD5, FasL and p53. (4) Daphnetin and 5-aza-dc changed the structure of CIA rat synovial cells to show apoptotic changes and increased the rate of apoptosis.
  
  
  CONCLUSIONS
  Daphnetin can reduce the expression of DNMT1, DNMT3a and DNMT3b, which could result in the proapoptotic genes DR3, PDCD5, FasL and p53 being demethylated. Therefore, daphnetin can increase proapoptotic gene and protein expression resulting in structural apoptotic changes and an increase in early and late CIA rat synovial cell apoptosis.
authors.affiliation: Department of Immunology, Medical College of Nanchang University; Institute of Immunology and Immunotherapy, Nanchang University and Jiangxi Academy of Medical Sciences, Nanchang, China. kshu@126.com.|Department of Gynecological Oncology, Jiangxi Maternity and Child Healthcare Hospital, Nanchang, China. kshu@126.com.
authors.forename: Kuanyong
authors.initials: K
authors.lastname: Shu
authors.affiliation: Department of Immunology, Medical College of Nanchang University; Institute of Immunology and Immunotherapy, Nanchang University and Jiangxi Academy of Medical Sciences, Nanchang, China. 463921200@qq.com.
authors.forename: Nanzhen
authors.initials: N
authors.lastname: Kuang
authors.affiliation: Reproductive Center, Jiangxi Maternal and Child Health Care Hospital, Nanchang, China. jgslsg@163.com.
authors.forename: Zhiqin
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Affiliated Stomatological Hospital of Nanchang University, Nanchang, China. hzling1111@126.com.
authors.forename: Ziling
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Department of Immunology, Medical College of Nanchang University; Institute of Immunology and Immunotherapy, Nanchang University and Jiangxi Academy of Medical Sciences, Nanchang, China. zyj900203@sina.com.
authors.forename: Yujuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Immunology, Medical College of Nanchang University; Institute of Immunology and Immunotherapy, Nanchang University and Jiangxi Academy of Medical Sciences, Nanchang, China. yingyuan1954@163.com.
authors.forename: Yingyuan
authors.initials: Y
authors.lastname: Fu
authors.affiliation: Department of Immunology, Medical College of Nanchang University; Institute of Immunology and Immunotherapy, Nanchang University and Jiangxi Academy of Medical Sciences, Nanchang, China. weiping.min@gmail.com.
authors.forename: Weiping
authors.initials: W
authors.lastname: Min
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics*; D001169:Arthritis, Experimental / Q000188:drug therapy* / Q000235:genetics*; D001327:Autoimmune Diseases / Q000188:drug therapy* / Q000235:genetics; D001374:Azacitidine / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D019175:DNA Methylation / Q000187:drug effects / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects; D009336:Necrosis; D011419:Propidium / Q000378:metabolism; D051381:Rats; D013583:Synovial Membrane / Q000187:drug effects / Q000473:pathology*; D014468:Umbelliferones / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D017304:Annexin A5; D014468:Umbelliferones; D011419:Propidium; D001374:Azacitidine; C039952:daphnetin