Sulforaphane has opposing effects on TNF-alpha stimulated and unstimulated synoviocytes.
BACKGROUND
Rheumatoid arthritis (RA) is characterized by progressive inflammation associated with rampantly proliferating synoviocytes and joint destruction due to oxidative stress. Recently, we described nuclear factor erythroid 2-related factor 2 (Nrf2) as a major requirement for limiting cartilage destruction. NF-κB and AP-1 are the main transcription factors triggering the inflammatory progression in RA. We used sulforaphane, an isothiocyanate, which is both an Nrf2 inducer and a NF-κB and AP-1 inhibitor.


METHODS
Cultured synoviocytes were stimulated with sulforaphane (SFN) with or without TNF-α pre-treatment. NF-κB, AP-1, and Nrf2 activation was investigated via dual luciferase reporter gene assays. Matrix metalloproteinases (MMPs) were measured via zymography and luminex technique. Cytokine levels were detected using ELISA. Cell viability, apoptosis and caspase activity were studied. Cell proliferation was analysed by real-time cell analysis.


RESULTS
SFN treatment decreased inflammation and proliferation dose-dependently in TNF-α-stimulated synoviocytes. SFN did not reduce MMP-3 and MMP-9 activity or expression significantly. Interestingly, we demonstrated that SFN has opposing effects on naïve and TNF-α-stimulated synoviocytes. In naïve cells, SFN activated the cytoprotective transcription factor Nrf2. In marked contrast to this, SFN induced apoptosis in TNF-α-pre-stimulated synoviocytes.


CONCLUSIONS
We were able to show that SFN treatment acts contrary on naïve and inflammatory synoviocytes. SFN induces the cytoprotective transcription factor Nrf2 in naïve synoviocytes, whereas it induces apoptosis in inflamed synoviocytes. These findings indicate that the use of sulforaphane might be considered as an adjunctive therapeutic strategy to combat inflammation, pannus formation, and cartilage destruction in RA.
Athanassios
A
Fragoulis
Jendrik
J
Laufs
Susanna
S
Müller
Ulf
U
Soppa
Stephanie
S
Siegl
Lucy Kathleen
LK
Reiss
Mersedeh
M
Tohidnezhad
Christian
C
Rosen
Klaus
K
Tenbrock
Deike
D
Varoga
Sebastian
S
Lippross
Thomas
T
Pufe
Christoph Jan
CJ
Wruck
D017209:Apoptosis / Q000187:drug effects; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D017879:Isothiocyanates / Q000494:pharmacology*; D051267:NF-E2-Related Factor 2 / Q000819:agonists* / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013454:Sulfoxides; D013583:Synovial Membrane / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D016207:Cytokines; D017879:Isothiocyanates; D051267:NF-E2-Related Factor 2; D016328:NF-kappa B; C495635:NFE2L2 protein, human; D013454:Sulfoxides; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D020169:Caspases; C016766:sulforaphane