Effects of leptin and tumor necrosis factor-alpha on degranulation and superoxide production of polymorphonuclear neutrophils from Holstein cows
2007
Ahmed, M.(Hokkaido Univ., Sapporo (Japan)) | Kimura, K. | Soliman, M. | Yamaji, D. | Okamatsu Ogura, Y. | Makondo, K. | Inanami, O. | Saito, M.
Leptin, a pleiotropic hormone regulating food intake and energy expenditure, has been shown directly to modulate human polymorphonuclear neutrophil (PMN) functions or indirectly through the action of tumor necrosis factor-alpha (TNF-alpha). Bovine PMN has considerable different characteristics from human PMN. For example, it does not respond to N-formyl-methionyl-leucyl-phenylalanine, a well known human PMN activator. In the present study, we tested the effects of leptin and TNF-alpha on superoxide production and degranulation of bovine peripheral PMN, in which both long isoforms of leptin receptor (Ob-Rb) and TNF receptor 1 were expressed. Human leptin, human TNF-alpha, phorbol myristate acetate (PMA) and opsonized zymosan particles (OZP) did not stimulate degranulation responses, while zymosan-activated serum (ZAS) did. Neither leptin nor TNF-alpha enhanced the ZAS-induced degranulation responses. TNF-alpha, PMA, OZP and ZAS increased superoxide production in different magnitudes, whereas leptin did not. TNF-alpha, but not leptin, enhanced OZP- and ZAS-induced superoxide production, possibly, in part due to facilitating translocation of p47phox, a component of NADPH oxidase. These results indicate that, unlike in human PMN, leptin does not have any direct effect on degranulation and superoxide production in bovine PMN, although TNF-alpha influences superoxide production.
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