Cell micropatterning reveals the modulatory effect of cell shape on proliferation through intracellular calcium transients

Abstract

The mechanism by which cell shape regulates the function of the cell is one of the most important biological issues, but it remains unclear. Here, we investigated the effect of the regulation of cell shape on proliferation by using a micropatterning approach to confine MC3T3-E1 cells into specific shapes. Our results show that the proliferation rate for rectangle-, triangle-, square- and circle-shaped osteoblasts increased sequentially and was related to the nuclear shape index (NSI) but not the cell shape index (CSI). Interestingly, intracellular calcium transients also displayed different patterns, with the number of Ca peaks increasing with the NSI in shaped cells. Further causal investigation revealed that the gene expression levels of the inositol 1,4,5-triphosphate receptor 1 (IP3R1) and sarco/endoplasmic reticulum Ca-ATPase 2 (SERCA2), two major calcium cycling proteins in the endoplasmic reticulum (ER), were increased with an increase in NSI as a result of nuclear volume changes. Moreover, the down-regulation of IP3R1 and/or SERCA2 using shRNAs in circle-shaped or control osteoblasts resulted in changes in intracellular calcium transient patterns and cell proliferation rates towards that of smaller-NSI-shaped cells. Our results indicate that changes in cell shape changed nuclear morphology and then the gene expression of IP3R1 and SERCA2, which produced different intracellular calcium transient patterns. The patterns of intracellular calcium transients then determined the proliferation rate of the shaped osteoblasts.

Improved activity of MC3T3-E1 cells by the exciting piezoelectric BaTiO3/TC4 using low-intensity pulsed ultrasound

“…For example, calcium-sensing receptor is able to functionally couple to integrins, in conjunction with facilitating intracellular calcium release, to promote cellular adhesion and migration [ 36 ]. The promoted calcium in MC3T3-E1 cells of G 0 /G 1 phase is able to initiate the tricarboxylic acid cycle, which in turn activates downstream pathways involved in cell proliferation [ 37 , 38 ]. The promoted calcium also allows to facilitate osteogenic differentiation via the Ca 2+ /CaMKII/ERK/AP-1 signaling pathway [ 39 ].…”

Membrane curvature sensing of the lipid-anchored K-Ras small GTPase

“…Furthermore, the growth factor–stimulated activation of MAPKs in flatter NIH3T3 cells is rapid and transient but becomes gradual and persistent in the elongated NIH3T3 cells (9). The proliferation rate is sequentially increased in mouse osteoblast cells confined to rectangular, triangular, square, or circular shapes (15). Growth and proliferation of pancreatic, gastrointestinal, breast, and prostate tumor cells display a similar dependence on cell shape (11,17,18).…”

Impact of heat treatment on anti-oxidative and anti-colon cancer activities of the soluble extracts from black mulberry (Morus nigra L.) using water and ethanol–water solvents

“…The cells treated with 0.1% of Triton X-100 (v/v) were used to determine the maximal uorescence, followed by an addition of 10 mmol L À1 EGTA (ethylene glycol tetra-acetic acid, pH 9.0) to determine the minimal uorescence as previously described. 35…”