Cystamine induces toxicity in hepatocytes through the elevation of cytosolic Ca2+ and the stimulation of a nonlysosomal proteolytic system

Journal Article · Wed Nov 05 04:00:00 EST 1986 · J. Biol. Chem.; (United States)

OSTI ID:6962550

Nicotera, P; Hartzell, P; Baldi, C; Svensson, S A; Bellomo, G; Orrenius, S

Infusion of cystamine into the isolated, perfused rat liver resulted in tissue damage preceded by the formation of cystamine-protein mixed disulfides which were mainly detected in the plasma membrane fraction. Hepatotoxicity was prevented when dithiothreitol was infused after cystamine or when the calcium antagonist, verapamil, was co-infused with the disulfide. In isolated hepatocytes, the formation of cystamine-protein mixed disulfides was associated with an inhibition of plasma membrane Ca/sup 2 +/-ATPase activity and a decreased rate of Ca/sup 2 +/ efflux from the cells. This resulted in intracellular Ca/sup 2 +/ accumulation which was followed by a stimulation of both phospholipid hydrolysis and proteolysis, as indicated by enhanced rates of release of radioactivity from hepatocytes prelabeled with (/sup 14/C)arachidonate and (/sup 14/C)valine, respectively. Preincubation of hepatocytes with the calmodulin inhibitor, calmidazolium, or with the phospholipase inhibitors, chlorpromazine and dibucaine, inhibited the stimulation of (/sup 14/C)arachidonate release by cystamine. However, none of these agents prevented the onset of cystamine toxicity in hepatocytes. In contrast, pretreatment of the cells with antipain or leupeptin, two inhibitors of Ca/sup 2 +/-activated proteases, abolished the stimulation of proteolysis by cystamine and also protected the cells from cystamine toxicity. Our results suggest that the perturbation of intracellular Ca/sup 2 +/ homeostasis by cystamine is caused by the inhibition of Ca/sup 2 +/ efflux associated with the formation of cystamine-protein mixed disulfides in the plasma membrane and that subsequent cytotoxicity results from Ca/sup 2 +/-activation of a nonlysosomal proteolytic system.

• Research Organization: Karolinska Institutet, Stockholm, Sweden
• OSTI ID: 6962550
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 31; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201 -- Biochemistry-- Tracer Techniques
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALINE EARTH METALS
AMINES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
ARACHIDONIC ACID
BODY
CALCIUM
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CYSTAMINE
DIGESTIVE SYSTEM
DRUGS
ELEMENTS
ENZYMES
GLANDS
HYDROLASES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIVER
LIVER CELLS
LYSOSOMES
MAMMALS
METALS
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANOIDS
ORGANS
PEPTIDE HYDROLASES
RADIOPROTECTIVE SUBSTANCES
RATS
RODENTS
SOMATIC CELLS
TOXICITY
TRACER TECHNIQUES
VALINE
VERTEBRATES