TY - JOUR
T1 - Pro-inflammatory Cytokines Drive Deregulation of Potassium Channel Expression in Primary Synovial Fibroblasts
AU - Haidar, Omar
AU - O'Neill, Nathanael
AU - Staunton, Caroline A
AU - Bavan, Selvan
AU - O'Brien, Fiona
AU - Zouggari, Sarah
AU - Sharif, Umar
AU - Mobasheri, Ali
AU - Kumagai, Kosuke
AU - Barrett-Jolley, Richard
N1 - Funding Information:
This study was funded by the European Union’s Seventh Framework Programme (EU FP7; grant agreement No. 305815), BBSRC (BB/N003020/1), The University of Liverpool, and King Abdulaziz University, Jeddah, Saudi Arabia.
Publisher Copyright:
© Copyright © 2020 Haidar, O’Neill, Staunton, Bavan, O’Brien, Zouggari, Sharif, Mobasheri, Kumagai and Barrett-Jolley.
PY - 2020/3/24
Y1 - 2020/3/24
N2 - The synovium secretes synovial fluid, but is also richly innervated with nociceptors and acts as a gateway between avascular joint tissues and the circulatory system. Resident fibroblast-like synoviocytes' (FLS) calcium-activated potassium channels (KCa) change in activity in arthritis models and this correlates with FLS activation.Objective: To investigate this activation in an in vitro model of inflammatory arthritis; 72 h treatment with cytokines TNFα and IL1β.Methods: FLS cells were isolated from rat synovial membranes. We analyzed global changes in FLS mRNA by RNA-sequencing, then focused on FLS ion channel genes and the corresponding FLS electrophysiological phenotype and finally modeling data with ingenuity pathway analysis (IPA) and MATLAB.Results: IPA showed significant activation of inflammatory, osteoarthritic and calcium signaling canonical pathways by cytokines, and we identified ∼200 channel gene transcripts. The large KCa (BK) channel consists of the pore forming Kcnma1 together with β-subunits. Following cytokine treatment, a significant increase in Kcnma1 RNA abundance was detected by qPCR and changes in several ion channels were detected by RNA-sequencing, including a loss of BK channel β-subunit expression Kcnmb1/2 and an increase in Kcnmb3. In electrophysiological experiments, there was a decrease in over-all current density at 20 mV without change in chord conductance at this potential.Conclusion: TNFα and IL1β treatment of FLS in vitro recapitulated several common features of inflammatory arthritis at the transcriptomic level, including increase in Kcnma1 and Kcnmb3 gene expression.
AB - The synovium secretes synovial fluid, but is also richly innervated with nociceptors and acts as a gateway between avascular joint tissues and the circulatory system. Resident fibroblast-like synoviocytes' (FLS) calcium-activated potassium channels (KCa) change in activity in arthritis models and this correlates with FLS activation.Objective: To investigate this activation in an in vitro model of inflammatory arthritis; 72 h treatment with cytokines TNFα and IL1β.Methods: FLS cells were isolated from rat synovial membranes. We analyzed global changes in FLS mRNA by RNA-sequencing, then focused on FLS ion channel genes and the corresponding FLS electrophysiological phenotype and finally modeling data with ingenuity pathway analysis (IPA) and MATLAB.Results: IPA showed significant activation of inflammatory, osteoarthritic and calcium signaling canonical pathways by cytokines, and we identified ∼200 channel gene transcripts. The large KCa (BK) channel consists of the pore forming Kcnma1 together with β-subunits. Following cytokine treatment, a significant increase in Kcnma1 RNA abundance was detected by qPCR and changes in several ion channels were detected by RNA-sequencing, including a loss of BK channel β-subunit expression Kcnmb1/2 and an increase in Kcnmb3. In electrophysiological experiments, there was a decrease in over-all current density at 20 mV without change in chord conductance at this potential.Conclusion: TNFα and IL1β treatment of FLS in vitro recapitulated several common features of inflammatory arthritis at the transcriptomic level, including increase in Kcnma1 and Kcnmb3 gene expression.
KW - IL1β
KW - TNFα
KW - inflammation
KW - ion channel
KW - synovial fibroblast
UR - http://www.scopus.com/inward/record.url?scp=85083087542&partnerID=8YFLogxK
U2 - 10.3389/fphys.2020.00226
DO - 10.3389/fphys.2020.00226
M3 - Article
C2 - 32265733
SN - 1664-042X
VL - 11
SP - 1
EP - 13
JO - Frontiers in Physiology
JF - Frontiers in Physiology
M1 - 226
ER -