TY  - INPR
Y1  - 2019///
AV  - public
TI  - Mechanical loading inhibits cartilage inflammatory signalling via an HDAC6 and IFT-dependent mechanism regulating primary cilia elongation
N1  - This version is the author accepted manuscript. For information on re-use, please refer to the publisher?s terms and conditions. // © 2019 The Author(s). Published by Elsevier Ltd on behalf of Osteoarthritis Research Society International. This is an open access article under the CC BY license (http://creativecommons.org/ licenses /by/4.0/).
UR  - https://doi.org/10.1016/j.joca.2019.03.003
SN  - 1063-4584
N2  - OBJECTIVE: Physiological mechanical loading reduces inflammatory signalling in numerous cell types including articular chondrocytes however the mechanism responsible remains unclear. This study investigates the role of chondrocyte primary cilia and associated intraflagellar transport (IFT) in the mechanical regulation of interleukin-1? (IL-1?) signalling. DESIGN: Isolated chondrocytes and cartilage explants were subjected to cyclic mechanical loading in the presence and absence of the cytokine IL-1?. Nitric oxide (NO) and PGE2 release were used to monitor IL-1? signalling whilst sGAG release provided measurement of cartilage degradation. Measurements were made of HDAC6 activity and tubulin polymerisation and acetylation. Effects on primary cilia were monitored by confocal and super resolution microscopy. Involvement of IFT was analysed using ORPK cells with hypomorphic mutation of IFT88. RESULTS: Mechanical loading supressed NO and PGE2 release and prevented cartilage degradation. Loading activated HDAC6 and disrupted tubulin acetylation and cilia elongation induced by IL-1?. HDAC6 inhibition with tubacin blocked the anti-inflammatory effects of loading and restored tubulin acetylation and cilia elongation. Hypomorphic mutation of IFT88 reduced IL-1? signalling and abolished the anti-inflammatory effects of loading indicating the mechanism is IFT-dependent. Loading reduced the pool of non-polymerised tubulin which was replicated by taxol which also mimicked the anti-inflammatory effects of mechanical loading and prevented cilia elongation. CONCLUSIONS: This study reveals that mechanical loading suppresses inflammatory signalling, partially dependent on IFT, by activation of HDAC6 and post transcriptional modulation of tubulin.
ID  - discovery10071980
A1  - Fu Md, S
A1  - Thompson PhD, CL
A1  - Ali, A
A1  - Wang PhD, W
A1  - Chapple PhD, P
A1  - Mitchison Phd, HM
A1  - Beales, PL
A1  - Wann PhD, AK
A1  - Knight PhD, MM
KW  - HDAC6
KW  -  IFT
KW  -  IL-1?
KW  -  chondrocyte
KW  -  primary cilia
KW  -  tubulin
JF  - Osteoarthritis Cartilage
ER  -