IL-6 and TNF-a Cooperate to Modulate Cell Cycle of RA-FLS Via Cyclin Dependent Kinase 6

Kenta Kaneshiro¹, Kohsuke Yoshida¹, Koto Uchida¹, Alisa Yaekura¹, Ikumi Okumura¹, Koji Tateishi², Yasuhiro Terashima², Nao Shibanuma³, Yoshitada Sakai⁴ and Akira Hashiramoto¹, ¹Department of Biophysics, Kobe University Graduate School of Health Sciences, Kobe, Japan, ²Dept. of Orthopaedic Surgery, Konan Kakogawa Hospital, Kakogawa, Japan, ³Departmant of Orthopaedic Surgery, Kobe Kaisei Hospital, Kobe, Japan, ⁴Division of Rehabilitation Medicine, Kobe University Graduate School of Medicine, Kobe, Japan

Meeting: 2018 ACR/ARHP Annual Meeting

Keywords: cytokines, rheumatoid arthritis (RA) and synovial cells, synovial fluid

Session Information

Date: Monday, October 22, 2018

Title: Cytokines and Cell Trafficking Poster

Session Type: ACR Poster Session B

Session Time: 9:00AM-11:00AM

Background/Purpose:

Rheumatoid Arthritis (RA) is a chronic inflammatory disease characterized by a tumor-like synovial overgrowth leading to joint destructions.

IL-6 and TNF-a play an important role in the pathogenesis of RA, and the proliferation of RA-synoviocytes (FLS) is controlled by cell cycle regulators including Cyclins, Cyclin dependent kinases (CDK), CDK inhibitors (CKDIs) and retinoblastoma protein (RB).

To reveal actions of proinflammatory cytokines on the cell cycle of RA-FLS, we examined the expressions of the cell cycle regulators and the cellular viability under stimulations of IL-6 and TNF-a.

Methods:

RA-FLS were treated with or without IL-6/soluble IL-6 receptor (sIL-6R) (100ng/ml) or TNF-a (10ng/ml). The expressions of CDK4/6 CDKIs (p16^INK4a, p21^Cip1, p27^Kip1) and Cyclin E1/2 mRNA were measured by Real-time PCR, the protein expression of CYCLIN D, CYCLIN E, RB and the phosphorylation of RB were measured by Western blot, the expression of CYCLIN D and the phosphorylation of RB were observed by immunofluorescence, and the cellular viabilities were measured by WST-8 and BrdU assay. In addition, siRNA/CDK6 was introduced into RA-FLS to measure the cellular viabilities, under stimulations with or without IL-6/sIL-6R or TNF-a.

Results:

IL-6/sIL-6R decreased the mRNA expression of p16^INK4a, whereas increased the protein expression of CYCLIN D and RB. TNF-a decreased the mRNA expressions of CDK4, whereas increased the mRNA expressions of p27^Kip1, CDK6, Cyclin E1/2 mRNA, the protein expression of CYCLIN D, RB and the phosphorylation of RB. The protein expression of CYCLIN D and the phosphorylation of RB were synergistically increased by IL-6 and TNF-a. The cellular viabilies were increased by IL-6 and TNF-a, which were suppressed by siRNA/CDK6.

Conclusion:

Results indicate that IL-6 and TNF-a interact with each other in regulating the cell cycle of RA-FLS, and TNF-a dominantly increases the cellular viability via CDK6.

Disclosure: K. Kaneshiro, None; K. Yoshida, None; K. Uchida, None; A. Yaekura, None; I. Okumura, None; K. Tateishi, None; Y. Terashima, None; N. Shibanuma, None; Y. Sakai, None; A. Hashiramoto, None.

To cite this abstract in AMA style:

Kaneshiro K, Yoshida K, Uchida K, Yaekura A, Okumura I, Tateishi K, Terashima Y, Shibanuma N, Sakai Y, Hashiramoto A. IL-6 and TNF-a Cooperate to Modulate Cell Cycle of RA-FLS Via Cyclin Dependent Kinase 6 [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 9). https://acrabstracts.org/abstract/il-6-and-tnf-a-cooperate-to-modulate-cell-cycle-of-ra-fls-via-cyclin-dependent-kinase-6/. Accessed .

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