Multiple calcium patterns of rat osteoblasts under fluidic shear stress

Abstract

The intracellular calcium ([Ca ] ) response induced by external forces can be diverse and complex. Using primary osteoblasts from Wistar rats, we found multiple patterns of [Ca ] responses induced by fluidic shear stress (Fss), including homogeneous non-oscillation and heterogeneous oscillations. These multiple-patterned [Ca ] responses could be influenced by Fss intensity, cell density, and cell differentiation. Our real-time measurements with free calcium, ATP, ATP without calcium, suramin, apyrase, and thapsigargin confirmed homogeneous [Ca ] patterns and/or heterogeneous [Ca ] oscillations with respect to the combined degree of external Ca influx, and intracellular Ca release. Our theoretical model supported diverse Fss-induced calcium activities as well. We concluded that a singular factor of Ca influx or release dominated to produce smooth homogeneous patterns, but combined factors produced oscillatory heterogeneous patterns. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2039-2051, 2018.

Role of intracellular Ca2+–based mechanotransduction of human periodontal ligament fibroblasts

“…Similar to a previous report on osteoblasts by Meng et al . (32), we observed 2 major patterns of [Ca 2+ ] i activity after compressive MS. After the early increased [Ca 2+ ] i signal spark, the first type is followed by the suppressed frequency of the signal spark (see cells 3, 4, and 9 in Fig. 2 H ), whereas the second type is followed by the increased frequency of the signal spark (see Fig.…”

“…Multiple patterns of [Ca 2+ ] i have been reported to be induced by physical and biochemical stimuli in other cell types ( e.g. , Hela cells and osteoblasts) (32, 36). Nevertheless, the causality of these multiple [Ca 2+ ] i patterns remains unclear.…”

“…This suggests that the other signaling pathways, including paracrine communication and ATP, may also induce hPDL cells to synchronize the MS-induced signals (35). Multiple patterns of [Ca 2+ ] i have been reported to be induced by physical and biochemical stimuli in other cell types (e.g., Hela cells and osteoblasts) (32,36). Nevertheless, the causality of these multiple [Ca 2+ ] i patterns remains unclear.…”

Regulation of intracellular Ca2+/CaMKII signaling by TRPV4 membrane translocation during osteoblastic differentiation

“…concentrations ([Ca 2? ] i ), which are crucial for bone homeostasis (Meng et al 2018;Zayzafoon 2006). Activating TRPV4 by its agonist GSK101 triggered significant [Ca 2? ]…”

“…i increase in response to GSK101 caused either an oscillatory or a sustained plateau pattern (supplementary Fig. S4); the former was known to play more important roles in regulating osteoblast gene expression and function (Meng et al 2018;Suzuki et al 2013). As summarized in Fig.…”