Open AccessTRPV4 mediates cell damage induced by hyperphysiological compression and regulates COX2 / PGE2 in intervertebral discs
Author(s) -
Cambria Elena,
Heusser Sally,
Scheuren Ariane C.,
Tam Wai Kit,
Karol Agnieszka A.,
Hitzl Wolfgang,
Leung Victor Y.,
Müller Ralph,
Ferguson Stephen J.,
WuertzKozak Karin
Publication year - 2021
Publication title -
jor spine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.125
0ISSN - 2572-1143
DOI - 10.1002/jsp2.1149
Subject(s) - trpv4 , mechanotransduction , microbiology and biotechnology , mapk/erk pathway , chemistry , in vivo , kinase , intervertebral disc , prostaglandin e2 , transient receptor potential channel , biochemistry , biology , receptor , anatomy , endocrinology
Abstract Background Aberrant mechanical loading of the spine causes intervertebral disc (IVD) degeneration and low back pain. Current therapies do not target the mediators of the underlying mechanosensing and mechanotransduction pathways, as these are poorly understood. This study investigated the role of the mechanosensitive transient receptor potential vanilloid 4 (TRPV4) ion channel in dynamic compression of bovine nucleus pulposus (NP) cells in vitro and mouse IVDs in vivo. Methods Degenerative changes and the expression of the inflammatory mediator cyclooxygenase 2 (COX2) were examined histologically in the IVDs of mouse tails that were dynamically compressed at a short repetitive hyperphysiological regime (vs sham). Bovine NP cells embedded in an agarose‐collagen hydrogel were dynamically compressed at a hyperphysiological regime in the presence or absence of the selective TRPV4 antagonist GSK2193874. Lactate dehydrogenase (LDH) and prostaglandin E2 (PGE2) release, as well as phosphorylation of mitogen‐activated protein kinases (MAPKs), were analyzed. Degenerative changes and COX2 expression were further evaluated in the IVDs of trpv4‐deficient mice (vs wild‐type; WT). Results Dynamic compression caused IVD degeneration in vivo as previously shown but did not affect COX2 expression. Dynamic compression significantly augmented LDH and PGE2 releases in vitro, which were significantly reduced by TRPV4 inhibition. Moreover, TRPV4 inhibition during dynamic compression increased the activation of the extracellular signal‐regulated kinases 1/2 (ERK) MAPK pathway by 3.13‐fold compared to non‐compressed samples. Trpv4‐deficient mice displayed mild IVD degeneration and decreased COX2 expression compared to WT mice. Conclusions TRPV4 therefore regulates COX2/PGE2 and mediates cell damage induced by hyperphysiological dynamic compression, possibly via ERK. Targeted TRPV4 inhibition or knockdown might thus constitute promising therapeutic approaches to treat patients suffering from IVD pathologies caused by aberrant mechanical stress.