CELLULAR CALCIUM SIGNALLING IS ALTERED IN HUMAN LYMPHOCYTES AFTER HYPOXIA

Becker D, Lechtermann A, Fromme A, Rudack P, Thorwesten L, Völker K, Mooren FC

Research article in edited proceedings (conference)

Abstract

Microenvironmental changes in oxygen partial pressure, caused by both pathological, e.g. ischemia, or physiological conditions, e.g. exhaustive exercise, have important effects on cellular signal transduction. PURPOSE To determine the influence of hypoxia on cellular calcium signalling in human lymphocytes. METHODS Human lymphocytes were isolated by density gradient centrifugation. Cells were incubated in medium at 37°C either under normoxic (75% N2; 5% CO2; 20% O2) or hypoxic (92% N2; 5% CO2; 3% O2) conditions for up to 1 hour. After reoxygenation cellular free calcium concentration ([Ca2+]i) was determined spectrophotometrically using the calcium sensitive dye Fura-2. RESULTS Basal intracellular calcium concentration of cells after normoxic incubation was 25.8±1.2 nmol/l. In contrast, cellular calcium concentration increased in a time-dependent fashion up to 230.1 + 16.6 nmol/l after 1 hour under hypoxic conditions. Moreover, phytohemagglutinin induced calcium transients decreased after hypoxia, while calcium mobilization via the CD3-receptor by OKT-3 was not affected. Performing the hypoxic incubation in calcium free medium or in the presence of lanthanum prevented the increase in basal calcium and restored the agonist induced calcium transients. The latter effect was also observed after pre-incubation of cells with a calpain inhibitor. CONCLUSION In lymphocytes hypoxia induces an increase of basal intracellular calcium preferentially by an influx of extracellular calcium. Furthermore, calcium dependent signaling seems to be specifically inhibited by a calcium dependent protease.

Details zur Publikation

Release year: 2003
Language in which the publication is written: English
Link to the full text: https://journals.lww.com/acsm-msse/Fulltext/2003/05001/CELLULAR_CALCIUM_SIGNALLING_IS_ALTERED_IN_HUMAN.1980.aspx