The antimicrobial activity of the appetite peptide hormone ghrelin.
The present study examined the antimicrobial activity of the peptide ghrelin. Both major forms of ghrelin, acylated ghrelin (AG) and desacylated ghrelin (DAG), demonstrated the same degree of bactericidal activity against Gram-negative Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa), while bactericidal effects against Gram-positive Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis) were minimal or absent, respectively. To elucidate the bactericidal mechanism of AG and DAG against bacteria, we monitored the effect of the cationic peptides on the zeta potential of E. coli. Our results show that AG and DAG similarly quenched the negative surface charge of E. coli, suggesting that ghrelin-mediated bactericidal effects are influenced by charge-dependent binding and not by acyl modification. Like most cationic antimicrobial peptides (CAMPs), we also found that the antibacterial activity of AG was attenuated in physiological NaCl concentration (150mM). Nonetheless, these findings indicate that both AG and DAG can act as CAMPs against Gram-negative bacteria.
Department of Immunology, Forsyth Institute, Cambridge, MA 02142, USA.
Christine
C
Min
Kouji
K
Ohta
Mikihito
M
Kajiya
Tongbo
T
Zhu
Kanika
K
Sharma
Jane
J
Shin
Hani
H
Mawardi
Mohammed
M
Howait
Josefine
J
Hirschfeld
Laila
L
Bahammam
Isao
I
Ichimonji
Srinivas
S
Ganta
Mansoor
M
Amiji
Toshihisa
T
Kawai
D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology; D001066:Appetite / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism; D054439:Ghrelin / Q000737:chemistry* / Q000494:pharmacology*; D006090:Gram-Negative Bacteria / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012965:Sodium Chloride / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000187:drug effects
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D054439:Ghrelin; D012965:Sodium Chloride