Blocking mechanosensitive ion channels eliminates the effects of applied mechanical loading on chick joint morphogenesis

Abstract

Abnormalities in joint shape are increasingly considered a critical risk factor for developing osteoarthritis in life. It has been shown that mechanical forces during prenatal development, particularly those due to fetal movements, play a fundamental role in joint morphogenesis. However, how mechanical stimuli are sensed or transduced in developing joint tissues is unclear. Stretch-activated and voltage-gated calcium ion channels have been shown to be involved in the mechanoregulation of chondrocytes in vitro. In this study, we analyse, for the first time, how blocking these ion channels influences the effects of mechanical loading on chick joint morphogenesis. Using in vitro culture of embryonic chick hindlimb explants in a mechanostimulation bioreactor, we block stretch-activated and voltage-gated ion channels using, respectively, gadolinium chloride and nifedipine. We find that the administration of high doses of either drug largely removed the effects of mechanical stimulation on growth and shape development in vitro, while neither drug had any effect in static cultures. This study demonstrates that, during joint morphogenesis, mechanical cues are transduced—at least in part—through mechanosensitive calcium ion channels, advancing our understanding of cartilage development and mechanotransduction.This article is part of the Theo Murphy meeting issue ‘Mechanics of development’.

Quantifying the tolerance of chick hip joint development to temporary paralysis and the potential for recovery

“…This in vivo recovery supports the conclusions of in vitro tissue explant models, in which externally applied movements affect the shapes of developing limb rudiments. 18,19,24 Our results demonstrate that shape at e9 is tightly linked with successful cavitation, as previously proposed. 9 When cavitation was consistently classified as normal (most notably in the single-day paralysis group), there were limited effects on joint shape compared to controls, whilst when cavitation was consistently absent in the I3-8, I4-8, and I5-8 sustained paralysis groups, all aspects of joint shape measured were substantially decreased relative to controls (Figures 2 and 4).…”

“…Therefore, a severe reduction in early whole‐body movements can be compensated for to some degree by applied, localized movements. This in vivo recovery supports the conclusions of in vitro tissue explant models, in which externally applied movements affect the shapes of developing limb rudiments 18,19,24 …”

“…Both the magnitude and temporal profile of fetal movements may be crucial to joint development. The magnitude of movements required for healthy joint morphogenesis has been investigated using in vitro culture of developing limbs in a mechano-stimulation bioreactor, 18,19 while less is known about the temporal profile of movements needed to promote normal joint development. Drachman and Coulombre 20 found that later periods of paralysis (initiated between 13 and 15 days) had more severe effects on joint angulation than earlier periods of paralysis (initiated between 7 and 12 days), and that a two-day period of paralysis had effects on joint mobility which persisted after hatching.…”

Mechanical Strain-Mediated Tenogenic Differentiation of Mesenchymal Stromal Cells Is Regulated through Epithelial Sodium Channels

“…Several studies have reported that ion channels residing in the plasma membrane of chondrocytes and osteoblasts are involved in the transduction of mechanical signals [7][8][9]. The existence of ENaC in load-bearing cells suggests that ENaC has a mechanoactive role in cellular signalling.…”

“…Each cell was stained with Hoechst (blue) to reveal the nucleus, and the images were merged with the corresponding fibronectin or N-cadherin (green). S -: no mechanical stimulation; S + : cyclic stretching applied; B -: no benzamil; B + : with ENaC inhibitor, benzamil 8. Stem Cells International which in turn phosphorylates C-Jun leading to an increased transcriptional activity.…”