Enzymatically depolymerized alginate oligomers that cause cytotoxic cytokine production in human mononuclear cells.
Enzymatically depolymerized guluronate and mannuronate oligomers were prepared from polyuronates with an alginate lyase from a Pseudoalteromonas sp., and their effects on mononuclear cells from human peripheral blood were examined. Conditioned medium prepared by the incubation of cells with an untreated polyuronate had little effect on growth of human leukemic U937 cells, but a medium prepared with depolymerized uronate oligomers inhibited their growth. Inhibition was greater in a medium prepared with guluronate oligomer than one prepared with mannuronate oligomer. The cytotoxic activity of the medium was heat-labile and nondialyzable. Apoptotic nuclear morphological changes and increased caspase-3-like activity were found in U937 cells treated with a medium prepared with depolymerized uronates. The medium prepared with purified tetra-guluronate and tetra-mannuronate also was cytotoxic; these effects were inhibited by antibodies to tumor necrosis factor-alpha. Our results suggested that enzymatically depolymerized guluronate and mannuronate oligomers induced the production of cytotoxic cytokines in human mononuclear cells, although the uronate polymers before depolymerization had no such activity.
Division of Biochemistry, Faculty of Fisheries, Nagasaki University, Nagasaki 852-8521, Japan.
Yoshiko
Y
Iwamoto
Xu
X
Xu
Tadashi
T
Tamura
Tatsuya
T
Oda
Tsuyoshi
T
Muramatsu
D000464:Alginates / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D020591:Alteromonas / Q000201:enzymology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001704:Biopolymers / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D016207:Cytokines / Q000096:biosynthesis*; D003601:Cytotoxicity Tests, Immunologic; D006603:Hexuronic Acids / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D011133:Polysaccharide-Lyases / Q000378:metabolism; D020298:U937 Cells; D014574:Uronic Acids / Q000737:chemistry / Q000494:pharmacology
D000464:Alginates; D001704:Biopolymers; D016207:Cytokines; D006603:Hexuronic Acids; D014574:Uronic Acids; C007896:guluronic acid; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D011133:Polysaccharide-Lyases