Antimicrobial Cathelicidin Peptide LL-37 Inhibits the LPS/ATP-Induced Pyroptosis of Macrophages by Dual Mechanism

Zhongshuang Hu,Toshiaki Iba,Kyoko Kuwahara-Arai,Hiroshi Tamura,Kaori Suzuki,Taisuke Murakami,Isao Nagaoka,David M Ojcius

doi:10.1371/journal.pone.0085765

Zhongshuang Hu, Toshiaki Iba + Show 6 more

Open Access

https://doi.org/10.1371/journal.pone.0085765

Copy DOI

Journal: PloS one	Publication Date: Jan 16, 2014
Citations: 149	License type: CC BY 4.0

Affiliation: Juntendo University

Abstract

Pyroptosis is a caspase-1 dependent cell death, associated with proinflammatory cytokine production, and is considered to play a crucial role in sepsis. Pyroptosis is induced by the two distinct stimuli, microbial PAMPs (pathogen associated molecular patterns) and endogenous DAMPs (damage associated molecular patterns). Importantly, cathelicidin-related AMPs (antimicrobial peptides) have a role in innate immune defense. Notably, human cathelicidin LL-37 exhibits the protective effect on the septic animal models. Thus, in this study, to elucidate the mechanism for the protective action of LL-37 on sepsis, we utilized LPS (lipopolysaccharide) and ATP (adenosine triphosphate) as a PAMP and a DAMP, respectively, and examined the effect of LL-37 on the LPS/ATP-induced pyroptosis of macrophage-like J774 cells. The data indicated that the stimulation of J774 cells with LPS and ATP induces the features of pyroptosis, including the expression of IL-1β mRNA and protein, activation of caspase-1, inflammasome formation and cell death. Moreover, LL-37 inhibits the LPS/ATP-induced IL-1β expression, caspase-1 activation, inflammasome formation, as well as cell death. Notably, LL-37 suppressed the LPS binding to target cells and ATP-induced/P2X7-mediated caspase-1 activation. Together these observations suggest that LL-37 potently inhibits the LPS/ATP-induced pyroptosis by both neutralizing the action of LPS and inhibiting the response of P2X7 to ATP. Thus, the present finding may provide a novel insight into the modulation of sepsis utilizing LL-37 with a dual action on the LPS binding and P2X7 activation.

Highlights

Sepsis is a systemic response that results from a harmful or damaging host response to infection, and is the most common cause of death in the noncoronary intensive care unit (ICU) [1]
The results indicated that LPS/ATP treatment induced the pyroptosis of mouse J774 macrophage-like cells, and LL-37 inhibited the LPS/ATP-induced features of pyroptosis, including IL-1b release, caspase-1 activation and cell death
LPS or ATP treatment alone did not induce the inflammasome formation; the ATP treatment of LPS-primed J774 cells considerably increased the inflammasome formation. These observations indicate that the treatment with both LPS and ATP induces the pyroptosis (IL-1b release, cell death accompanied with inflammasome formation) of J774 cells, as reported using mouse bone marrow-derived macrophages and human macrophage-like THP1 cells [37,38]

Summary

Introduction

Sepsis is a systemic response that results from a harmful or damaging host response to infection, and is the most common cause of death in the noncoronary intensive care unit (ICU) [1]. The dysregulation of inflammatory/immune responses is responsible for the multiple organ failure, for which over expression of proinflammatory cytokines is a major mechanism. Much attention has been focused on the mechanism of host cell death, which develops during sepsis and contributes to the dysregulated inflammatory/immune responses [5,6,7,8,9]. The activated caspase-1 processes and releases IL-1b, and induces cell death in an unidentified mechanism [15,18,19]

Methods

Results

Conclusion