title: Isolation and identification of novel neutrophil-activating cryptides hidden in mitochondrial cytochrome C.
abstract: Although it is known that neutrophils infiltrate damaged sites immediately after tissue injury, the endogenous factors that induce their acute transmigration and activation have not been thoroughly investigated. For the candidates of those factors, we recently discovered two novel neutrophil-activating cryptides, mitocryptide-1 (MCT-1) and mitocryptide-2 (MCT-2), hidden in mitochondrial proteins. In addition, many unknown neutrophil-activating peptides other than MCT-1 and MCT-2 were also observed during their purification. Here, we isolated and purified a novel neutrophil-activating peptide from porcine hearts, which we showed by structural analyses to have an identical primary structure to porcine mitochondrial cytochrome c (68-85). We named this novel functional octadecapeptide as mitocryptide-CYC (MCT-CYC). Structure-activity relationships of cytochrome c on β-hexosaminidase (β-HA) release from neutrophilic-differentiated HL- 60 cells demonstrated that peptides derived from the C-terminal part of cytochrome c induced β-HA release and that cytochrome c (70-85) was the most potent cryptide among them. Since cytochrome c is known to be involved in the apoptotic process, our results suggest that cryptides, including MCT-CYC, derived from mitochondrial cytochrome c are possible factors that induce scavenging of toxic debris produced from apoptotic cells by neutrophils.
authors.affiliation: Laboratory of Peptide Science, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829, Japan. hmukai-endo@umin.ac.jp.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Hokari
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Seki
authors.forename: Hiroko
authors.initials: H
authors.lastname: Nakano
authors.forename: Yuko
authors.initials: Y
authors.lastname: Matsuo
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Fukamizu
authors.forename: Eisuke
authors.initials: E
authors.lastname: Munekata
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kiso
authors.forename: Hidehito
authors.initials: H
authors.lastname: Mukai
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D018925:Chemokines / Q000378:metabolism; D045304:Cytochromes c / Q000737:chemistry*; D008929:Mitochondria, Heart / Q000737:chemistry / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009206:Myocardium / Q000737:chemistry; D009504:Neutrophils / Q000737:chemistry* / Q000378:metabolism; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D013552:Swine; D001619:beta-N-Acetylhexosaminidases / Q000378:metabolism
chemical_list: D018925:Chemokines; D024101:Mitochondrial Proteins; D010455:Peptides; D045304:Cytochromes c; D001619:beta-N-Acetylhexosaminidases