Commentary

Abstract

HIGHLIGHTED TOPICScommentaryPublished Online:01 Dec 2000https://doi.org/10.1152/jappl.2000.89.6.2497MoreSectionsPDF (47 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmail The first Highlighted Topics article in this issue of the Journal of Applied Physiology, “Regulatory pathways involved in mechanical induction of c-fos gene expression in bone cells” by Peake et al. (p. 2498–2507), describes the role of cell-matrix interactions and calcium-mediated signaling pathways in gene upregulation in response to dynamic mechanical loading of human osteoblasts. In particular, the paper investigates regulation of the early mechanoresponsive transcription factor c-fos, which has been shown to play a key role in bone development and the signaling cascade leading to load-induced osteogenesis. These results provide important insights into the possible requirement for key matrix components, which enable the load response of c-fos gene expression. The essential role of β1-integrin-mediated interactions is highlighted and is shown not to be interchangeable with certain non-integrin-mediated mechanisms. This study also indicates a lack of dependence on RGD-mediated mechanisms in longer-term experiments, which has not been widely noted. In addition, the expression of the early response gene c-fos is linked to an influx of calcium mediated through a gadolinium-attenuated membrane ion channel. This indicates that an interaction between a number of mechanisms (in particular, integrins and calcium signaling) is essential for this type of mechanotransduction. Whereas previous studies have almost exclusively focused on regulation of early cellular signaling events in the load response (e.g., membrane polarization effects and protein kinase activation), these studies provide novel data indicating critical steps in the activation of early gene transcription. Cellular and molecular techniques, like the ones used in this study, are relevant in addressing important questions in applied physiology.In the second Highlighted Topics article, “A three-dimensional model for assessment of in vitro toxicity inBalaena mysticetus renal tissue” (p. 2508–2517), Goodwin et al. construct the first three-dimensional cultures and clone the metallothionien protein from the bowhead whale, one of the planet's largest marine mammals. This marks an important advance in the ability of investigators to model these sea creatures and to assess, through cellular mechanics, the potential impact of terrestrially generated toxic agents on the ecosystem. The metallothionien protein is one of the primary binding sites for heavy metals for both marine mammals and humans. Because of similarities between marine mammals and humans, cloning of additional metallothionien proteins from marine mammals will serve to further illuminate potential global impacts from terrestrial and oceanic contaminants, which may threaten the environment. Nearly three-quarters of the Earth is covered by water, and this vast surface area represents the lifeblood of the planet with almost 90% of the oxygen regeneration capability of our environment. Therefore, reason would dictate that threats to the health of aquatic animals and the oceans could reflect significantly on the long-term survival of the ecosystem. This article illustrates the expanded scope of the Journal of Applied Physiology, with its emphasis on environmental physiology and the ability to use the techniques of cellular mechanics to address extremely important environmental issues.This article has no references to display. Previous Back to Top Next FiguresReferencesRelatedInformation More from this issue > Volume 89Issue 6December 2000Pages 2497-2497 Copyright & PermissionsCopyright © 2000 the American Physiological Societyhttps://doi.org/10.1152/jappl.2000.89.6.2497PubMed11090607History Published online 1 December 2000 Published in print 1 December 2000 PDF download Metrics Downloaded 78 times