English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Cathepsin G, a serine protease released by polymorphonuclear-leucocyte azurophilic granules upon stimulation, activates human platelets, inducing an increase in intra-platelet Ca2+ concentration ([Ca2+]i) in a concentration-dependent manner (50-200 nM). The [Ca2+]i rises elicited by low (50-80 nM) cathepsin G concentrations in fura-2-loaded platelets showed a biphasic mode, with a first small peak followed by a greater and more prolonged Ca2+ transient. Higher (100-200 nM) cathepsin G concentrations induced a monophasic increase in intracellular Ca2+. Acetylsalicylic acid, nordihydroguaiaretic acid and ketanserin did not affect platelet activation by cathepsin G, whereas the ADP-scavenger system phosphocreatine/creatine kinase significantly decreased Ca2+ mobilization, platelet aggregation and 5-hydroxytryptamine secretion by cathepsin G. Preventing cathepsin G-induced platelet aggregation with the synthetic peptide RGDSP (Arg-Gly-Asp-Ser-Pro) did not significantly affect cathepsin G-induced Ca2+ transients. Ni2+ (4 mM), a bivalent-cation-channel inhibitor, decreased the cathepsin G-induced fluorescence rise by more than 90%. This effect was reversed by either decreasing Ni2+ or increasing cathepsin G concentration. Preventing Ca2+ influx across the plasma membrane with 4 mM-EGTA totally abolished Ca2+ transients. However, EGTA also strongly decreased catalytic activity of cathepsin G, which is essential for platelet activation. Evidence of a rapid and sustained bivalent-cation channel opening in the platelet membrane was obtained by adding Mn2+ to the platelet suspension 30 s or 3 min after cathepsin G. No accumulation of InsP3 could be detected when platelets were stimulated with cathepsin G. All these data indicate that cathepsin G induces a [Ca2+]i increase mainly through an influx across the plasma membrane. This massive Ca2+ entry is probably due to opening of receptor-operated channels and is amplified by endogenous ADP release.

Intracellular Ca2+ rise in human platelets induced by polymorphonuclear-leucocyte-derived cathepsin G