Mechanosensitivity and intercellular communication in HOBIT osteoblastic cells: A possible role for gap junction hemichannels

Issue title: Selected papers of the Euromech Colloquium No. 420, Mechanobiology of Cells and Tissues

Article type: Research Article

Authors: Romanello, Milena | Veronesi, Valentina | D'Andrea, Paola

Affiliations: Dipartimento di Biochimica, Biofisica e Chimica delle Macromolecole, Università di Trieste, via Licio Giorgieri 1, I‐34127 Trieste, Italy Tel.: +39 40 676 3690; Fax: +39 40 676 3691; E‐mail: dandrea@bbcm.univ.trieste.it

Abstract: Mechanically induced intercellular Ca2+ signalling was investigated in differentiated HOBIT osteoblastic cells. HOBIT cells express connexin43 clustered at the cell‐to‐cell boundary and display functional intercellular coupling assessed by intercellular transfer of Lucifer yellow. Mechanical stimulation of single cells, besides leading to an intracellular Ca2+ rise, induced a wave of increased Ca2+ that was radially propagated to surrounding cells. Treatment of cells with thapsigargin blocked mechanically induced signal propagation. Intercellular Ca2+ spreading was inhibited by 18α‐glycyrrhetinic acid, demonstrating the involvement of gap junctions in signal propagation. Suramin and apyrase decreased the extent of wave propagation, suggesting that ATP‐mediated paracrine stimulation contribute to cell‐to‐cell signalling. The functional expression of gap‐junctional hemichannels was evidenced in experiments of Mn2+ quenching, extracellular dye uptake and intracellular Ca2+ release, activated by uptake of inositol 1,4,5‐trisphosphate from the external medium. Gap‐junctional hemichannels were activated by low extracellular Ca2+ concentrations and inhibited by 18α‐glycyrrhetinic acid.

Journal: Biorheology, vol. 40, no. 1-3, pp. 119-121, 2003