The effect of chemically defined medium on spontaneous calcium signaling of in situ chondrocytes during long-term culture

Zhou, Yilu; Park, Miri; Cheung, Enoch; Wang, Liyun; Lü, Xin

doi:10.1016/j.jbiomech.2015.02.005

Cited by 23 publications

(36 citation statements)

References 53 publications

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“…Previous studies have demonstrated that fluid flow induced calcium responses of chondrocytes are dependent on the ligand and scaffold structures 12, 13 . Our recent study found that the spontaneous [Ca 2+ ] i signaling of each in situ chondrocyte has a unique pattern and behaves like a “fingerprint” of the cells 54 .…”

Section: Discussionmentioning

confidence: 99%

“…In addition, recent studies proved that chondrocytes demonstrate spontaneous [Ca 2+ ] i oscillations, similar to those in neurons and myocytes. Without the presence of any external stimulation, chondrocytes located in hydrogels or their own ECM can release robust and repetitive [Ca 2+ ] i peaks 18, 32, 43, 54 . While most relevant studies have focused on the [Ca 2+ ] i response immediately upon exposure of osmotic shock, chondrocytes' spontaneous [Ca 2+ ] i signaling under various osmotic environments remains elusive.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Osmolarity on the Spontaneous Calcium Signaling of In Situ Juvenile and Adult Articular Chondrocytes

et al. 2015

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Calcium is a universal second messenger that mediates the metabolic activity of chondrocytes in articular cartilage. Spontaneous intracellular calcium ([Ca2+]i) oscillations, similar to those in neurons and myocytes, have recently been observed in chondrocytes. This study analyzed and compared the effects of different osmotic environments (hypertonic, hypotonic, and isotonic) on the spontaneous [Ca2+]i signaling of in situ chondrocytes residing in juvenile and adult cartilage explants. In spite of a lower cell density, a significantly higher percentage of chondrocytes in adult cartilage under all osmotic environments demonstrated spontaneous [Ca2+]i oscillations than chondrocytes in juvenile cartilage. For both juvenile and adult chondrocytes, hypotonic stress increased while hypertonic stress decreased the response rates. Furthermore, the spatiotemporal characteristics of the [Ca2+]i peaks vary in an age-dependent manner. In the hypotonic environment, the [Ca2+]i oscillation frequency of responsive adult cells is almost tripled whereas the juvenile cells respond with an increased duration and magnitude of each [Ca2+]i peak. Both juvenile and adult chondrocytes demonstrated significantly slower [Ca2+]i oscillations with longer rising and recovery time under the hypertonic condition. Taken together, these results shed new insights into the interplay between age and osmotic environment that may regulate the fundamental metabolism of chondrocytes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Osmolarity on the Spontaneous Calcium Signaling of In Situ Juvenile and Adult Articular Chondrocytes

et al. 2015

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“…The spatiotemporal parameters of the [Ca 2+ ] i peaks were defined following a standard protocol, as shown in Fig. 1C (19, 39), which include the normalized maximum magnitude of a peak ( m 1 ), the time from baseline to the peak ( t 1 ), and time from the peak value to 50% relaxation ( t 2 ).…”

Section: Methodsmentioning

confidence: 99%

“…In chondrocytes, [Ca 2+ ] i signaling can be induced and regulated by hydrostatic pressure (11), fluid flow (12), mechanical stimulation (13,14), or osmotic stress (15, 16). Recently, spontaneous [Ca 2+ ] i signaling has been discovered in chondrocytes in monolayer culture or tissue expiants (17–19). However, because of the variety of experimental conditions, the characteristics of the observed spontaneous [Ca 2+ ] i peaks vary significantly among different studies.…”

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confidence: 99%

Spontaneous calcium signaling of cartilage cells: from spatiotemporal features to biophysical modeling

Zhou

et al. 2019

FASEB j.

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Intracellular calcium ([Ca2+]i) oscillation is a fundamental signaling response of cartilage cells under mechanical loading or osmotic stress. Chondrocytes are usually considered as nonexcitable cells with no spontaneous [Ca2+]i signaling. This study proved that chondrocytes can exhibit robust spontaneous [Ca2+]i signaling without explicit external stimuli. The intensity of [Ca2+]i peaks from individual chondrocytes maintain a consistent spatiotemporal pattern, acting as a unique “fingerprint” for each cell. Statistical analysis revealed lognormal distributions of the temporal parameters of [Ca2+]i peaks, as well as strong linear correlations between their means and sds. Based on these statistical findings, we hypothesized that the spontaneous [Ca2+]i peaks may result from an autocatalytic process and that [Ca2+]i oscillation is controlled by a threshold‐regulating mechanism. To test these 2 mechanisms, we established a multistage biophysical model by assuming the spontaneous [Ca2+]i signaling of chondrocytes as a combination of deterministic and stochastic processes. The theoretical model successfully explained the lognormal distribution of the temporal parameters and the fingerprint feature of [Ca2+]i peaks. In addition, by using antagonists for 10 pathways, we revealed that the initiation of spontaneous [Ca2+]i peaks in chondrocytes requires the presence of extracellular Ca2+, and that the PLC‐inositol 1,4,5‐trisphosphate pathway, which controls the release of calcium from the endoplasmic reticulum, can affect the initiation of spontaneous [Ca2+]i peaks in chondrocytes. The purinoceptors and transient receptor potential vanilloid 4 channels on the plasma membrane also play key roles in the spontaneous [Ca2+]i signaling of chondrocytes. In contrast, blocking the T‐type or L‐type voltage‐gated calcium channel promoted the spontaneous calcium signaling. This study represents a systematic effort to understand the features and initiation mechanisms of spontaneous [Ca2+]i signaling in chondrocytes, which are critical for chondrocyte mechanobiology.—Zhou, Y., Lv, M., Li, T., Zhang, T., Duncan, R., Wang, L., Lu, X. L. Spontaneous calcium signaling of cartilage cells: from spatiotemporal features to biophysical modeling. FASEB J. 33, 4675–4687 (2019). http://www.fasebj.org

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“…For each cell, [Ca 2+ ] i concentration oscillation was represented by the fluorescent signal intensity of its transients. A cell was defined as responsive if a calcium peak was released with a magnitude four times higher than the maximum fluctuation along the baseline . The fraction of responsive cells over total cells was calculated as the responsive rate of a sample.…”

Section: Methodsmentioning

confidence: 99%

Calcium signaling of in situ chondrocytes in articular cartilage under compressive loading: Roles of calcium sources and cell membrane ion channels

Zhou

Chen

et al. 2017

Journal Orthopaedic Research

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Mechanical loading on articular cartilage can induce many physical and chemical stimuli on chondrocytes residing in the extracellular matrix (ECM). Intracellular calcium ([Ca ] ) signaling is among the earliest responses of chondrocytes to physical stimuli, but the [Ca ] signaling of in situ chondrocytes in loaded cartilage is not fully understood due to the technical challenges in [Ca ] imaging of chondrocytes in a deforming ECM. This study developed a novel bi-directional microscopy loading device that enables the record of transient [Ca ] responses of in situ chondrocytes in loaded cartilage. It was found that compressive loading significantly promoted [Ca ] signaling in chondrocytes with faster [Ca ] oscillations in comparison to the non-loaded cartilage. Seven [Ca ] signaling pathways were further investigated by treating the cartilage with antagonists prior to and/or during the loading. Removal of extracellular Ca ions completely abolished the [Ca ] responses of in situ chondrocytes, suggesting the indispensable role of extracellular Ca sources in initiating the [Ca ] signaling in chondrocytes. Depletion of intracellular Ca stores, inhibition of PLC-IP pathway, and block of purinergic receptors on plasma membrane led to significant reduction in the responsive rate of cells. Three types of ion channels that are regulated by different physical signals, TRPV4 (osmotic and mechanical stress), T-type VGCCs (electrical potential), and mechanical sensitive ion channels (mechanical loading) all demonstrated critical roles in controlling the [Ca ] responses of in situ chondrocyte in the loaded cartilage. This study provided new knowledge about the [Ca ] signaling and mechanobiology of chondrocytes in its natural residing environment. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:730-738, 2018.

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The effect of chemically defined medium on spontaneous calcium signaling of in situ chondrocytes during long-term culture

Cited by 23 publications

References 53 publications

Effects of Osmolarity on the Spontaneous Calcium Signaling of In Situ Juvenile and Adult Articular Chondrocytes

Effects of Osmolarity on the Spontaneous Calcium Signaling of In Situ Juvenile and Adult Articular Chondrocytes

Spontaneous calcium signaling of cartilage cells: from spatiotemporal features to biophysical modeling

Calcium signaling of in situ chondrocytes in articular cartilage under compressive loading: Roles of calcium sources and cell membrane ion channels

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