Abstract
IntroductionThe c-Jun N-terminal kinase (JNK) is a key regulator of matrix metalloproteinase (MMP) and cytokine production in rheumatoid arthritis (RA) and JNK deficiency markedly protects mice in animal models of arthritis. Cytokine-induced JNK activation is strictly dependent on the mitogen-activated protein kinase kinase 7 (MKK7) in fibroblast-like synoviocytes (FLS). Therefore, we evaluated whether targeting MKK7 using anti-sense oligonucleotides (ASO) would decrease JNK activation and severity in K/BxN serum transfer arthritis.MethodsThree 2'-O-methoxyethyl chimeric ASOs for MKK7 and control ASO were injected intravenously in normal C57BL/6 mice. PBS, control ASO or MKK7 ASO was injected from Day -8 to Day 10 in the passive K/BxN model. Ankle histology was evaluated using a semi-quantitative scoring system. Expression of MKK7 and JNK pathways was evaluated by quantitative PCR and Western blot analysis.ResultsMKK7 ASO decreased MKK7 mRNA and protein levels in ankles by about 40% in normal mice within three days. There was no effect of control ASO on MKK7 expression and MKK7 ASO did not affect MKK3, MKK4 or MKK6. Mice injected with MKK7 ASO had significantly less severe arthritis compared with control ASO (P < 0.01). Histologic evidence of synovial inflammation, bone erosion and cartilage damage was reduced in MKK7 ASO-treated mice (P < 0.01). MKK7 deficiency decreased phospho-JNK and phospho-c-Jun in ankle extracts (P < 0.05), but not phospho-MKK4. Interleukin-1beta (IL-1β), MMP3 and MMP13 gene expression in ankle joints were decreased by MKK7 ASO (P < 0.01).ConclusionsMKK7 plays a critical regulatory role in the JNK pathway in a murine model of arthritis. Targeting MKK7 rather than JNK could provide site and event specificity when treating synovitis.
Highlights
The c-Jun N-terminal kinase (JNK) is a key regulator of matrix metalloproteinase (MMP) and cytokine production in rheumatoid arthritis (RA) and JNK deficiency markedly protects mice in animal models of arthritis
JNK is activated via dual phosphorylation by two upstream mitogen activated protein kinase (MAPK) kinases (MKKs), MKK4 and mitogen-activated protein kinase kinase 7 (MKK7) [8,9,10]
Mice injected with MKK7 anti-sense oligonucleotides (ASO) had less severe arthritis from Day 4 to Day 10 compared with control ASO (Figure 2)
Summary
The c-Jun N-terminal kinase (JNK) is a key regulator of matrix metalloproteinase (MMP) and cytokine production in rheumatoid arthritis (RA) and JNK deficiency markedly protects mice in animal models of arthritis. We evaluated whether targeting MKK7 using anti-sense oligonucleotides (ASO) would decrease JNK activation and severity in K/BxN serum transfer arthritis. Rheumatoid arthritis (RA) is one of the most common immune-mediated diseases and is characterized by synovial inflammation and joint destruction [1]. Mitogenactivated protein kinases (MAPKs) are highly activated in rheumatoid synovium and potentially contribute to inflammatory and destructive mechanisms [2,3]. An alternative approach targeting the MKKs instead of JNK could suppress signaling responses that contribute to inflammatory arthritis but spare a subset of host defense or homoeostasis pathways
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
