Nuclear factor-erythroid 2-related 2 mRNA and protein are highly expressed in the synovium of patients with rheumatoid arthritis

Naoki Kondo, Takahiro Netsu, Katsumitsu Arai, Tomotake Kanai, Hiroshige Sano, Yasufumi Kijima, Go Okumura, Junichi Fujisawa, Naoto Endo
DOI: 10.15305/ijrci/v5i1/231


Introduction: Nuclear factor-erythroid 2-related factor 2 (Nrf2) is the main transcription factor for antioxidant stress response. The aim of this study was to analyze the expression level of Nrf2 mRNA and protein in the synovium of patients with rheumatoid arthritis (RA), and the association between Nrf2 mRNA and oxidative stress.

Materials and Methods: The synovia harvested from 41 patients with RA served as the study group and 4 cases with knee osteoarthritis (OA) were registered as the control group. The Nrf2 mRNA expression level was evaluated using real-time polymerase chain reaction (PCR) and the Nrf2 protein via immunohistochemistry. The immunopositivity of the Nrf2 protein was then graded into four stages (none, slight, moderate, and strong) during microscopic examination. In addition, d-reactive oxygen metabolites (d-ROM) measurement was performed using the sera of patients with RA.

Results: The expression level of Nrf2 mRNA in the RA synovia (2.34±0.86) was significantly higher than that in the OA synovia (1.5±0.49). The OA synovia had neither moderate nor strong intensity of Nrf2 protein immunopositivity. In the RA synovia, moderate and strong intensities were noted in 23 and three cases, respectively. The immunoreactivity of the Nrf2 protein in the RA synovia was significantly stronger than that in the OA synovia. The Nrf2 mRNA showed significantly correlation with preoperative d-ROM.

Conclusion: The present study demonstrated increased upregulation of Nrf2 in the RA synovia compared to that in the OA synovia both at the mRNA expression and protein levels. An increased expression of Nrf2 mRNA may reflect an upregulation of the antioxidant capacity in response to high oxidative stresses.


Kondo N, Netsu T, Arai K, Kanai T, Sano H, Kijima Y, Okumura G, Fujisawa J, Endo N. IJRCI. 2017;5(1):OA4 DOI: 10.15305/ijrci/v5i1/231


Rheumatoid arthritis; NF-E2 related factor 2; Nrf2; synovium; reactive oxygen metabolites; ROM; biological antioxidant potential; BAP


1. Filippin LI, Vercelino R, Marroni NP, Xavier M. Redox signaling and the inflammatory response in rheumatoid arthritis. Clin Exp Immunol 2008; 153 (3): 415-422.

2. Quinonez-Flores CM, Gonzalez-Chavez SA, Del Rio Najera D, Pacheco-Tena C. Oxidative stress relevance in the pathogenesis of rheumatoid arthritis: A systematic review. Biomed Research Int 2016; 2016: 6097417. Doi: 10.1155/2016/6097417.

3. Netsu T, Kondo N, Arai K, Fujisawa J, Endo N. The serum oxidative stress values before and after treatment of biologics in patients with rheumatoid arthritis. Arch Niigata Soc of Orthop Surg 2013; 29: 37-40. (In Japanese)

4. Yamanaka K, Kondo N, Arai K, Fujisawa J, Netsu T, Endo N. Etanercept decreases serum oxidative stress in patients with rheumatoid arthritis. Arch Niigata Soc Orthop Surg 2013; 29: 73-76. (In Japanese)

5. Kondo N, Arai K, Netsu T, Kanai T, Sano H, Okumura G, et al. Tocilizumab significantly decreases reactive oxygen species level in patients with rheumatoid arthritis. Open J Rheumatol Autoimmune Dis 2017; 7: 46-52.

6. Kim J, Cha YN, Surh YJ. A protective role of nuclear factor-erythroid 2-related factor-2 (Nrf2) in inflammatory disorders. Mutat Res 2010; 690: 12-23.

7. Wruck CJ, Fargoulis A, Gurzynski A, Brandenburg LO, Kan YW, Chan K, et al. Role of oxidative stress in rheumatoid arthritis: Insights from the Nrf2-knockout mice. Ann Rheum Dis 2011; 70(5): 844-850.

8. Maicas N, Ferrándiz ML, Brines R, Ibáñez L, Cuadrado A, Koenders MI, et al. Deficiency of Nrf2 accelerates the effector phase of arthritis and aggravates joint disease. Antioxid Redox Signal 2011; 15(4): 889-901.

9. Arnett FC, Edworthy SM, Bloch DA, McShane DJ, Fries JF, Cooper NS, et al. The American Rheumatism Association 1987 revised criteria for the classification of rheumatoid arthritis. Arthritis Rheum 1988; 31(3): 315-24.

10. Xu Y, Ogose A, Kawashima H, Hotta T, Ariizumi T, Li G, et al. High-level expression of podoplanin in benign and malignant soft tissue tumors: Immunohistochemical and quantitative real-time RT-PCR analysis. Oncol Rep 2011; 25: 599-607.

11. Nojima J, Motoki Y, Tsuneoka H, Kuratsune H, Matsui T, Yamamoto M, et al. “Oxidation stress index” as a possible clinical marker for the evaluation of non-Hodgkin lymphoma. Br J Haematology 2011; 155(4): 528-530.

12. Park SY, Lee SW, Shin HK, Chung WT, Lee WAS, Rhim BY, et al. Cilostazol enhances apoptosis of synovial cells from rheumatoid arthritis patients with inhibition of cytokine formation via Nrf2-linked heme oxygenase 1 induction. Arthritis Rheum 2010; 62(3): 732-741.

13. Kong P, Chen G, Jiang A, Wang Y, Song C, Zhuang J, et al. Sesamin inhibits IL-1β-stimulated inflammatory response in human osteoarthritis chondrocytes by activating Nrf2 signaling pathway. Oncotarget 2016; 7: 83720-83726.

14. Staron A, Makosa G, Koter-Michalak M. Oxidative stress in erythrocytes from patients with rheumatoid arthritis. Rheumatol Int 2012; 32(2): 331-334.

15. García-González A, Gaxiola-Robles R, Zenteno-Savín T. Oxidative stress in patients with rheumatoid arthritis. Rev Invest Clin 2015; 67(1): 46-53.

16. Jiang Y, Kou J, Han X, Li X, Zhong Z, Liu Z, et al. ROS-dependent activation of autophagy through the PI3K/Akt/mTOR pathway is induced by hydroxysafflor yellow A- sonodynamic therapy in THP-1 macrophages. Oxidative Medicine Cellular Longevity 2017; Article ID 8519169.

17. Miwa S, Czapiewski R. Wan T, Bell A, Hill KM, Zglinicki T, et al. Decreased mTOR signaling reduces mitochondrial ROS in brain via accumulation of the telomere protein TERT within mitochondria. Aging 2016; 8(10): 2551-2567.

18. Malemud CJ. Intracellular signaling pathways in rheumatoid arthritis. J Clin Cell Immunol 2014; 4: 160-. Doi: 10.4172/2155-9899.1000160.