Differential Internalization of Thrombin-Derived Host Defense Peptides into Monocytes and Macrophages

Proteolytic cleavage of thrombin generates C-terminal host defense peptides exerting multiple immunomodulatory effects in response to bacterial stimuli. Previously, we reported that thrombin-derived C-terminal peptides (TCPs) are internalized in monocytes and macrophages in a time- and temperature-dependent manner. In this study, we investigated which endocytosis pathways are responsible for the internalization of TCPs. Using confocal microscopy and flow cytometry, we show that both clathrin-dependent and clathrin-independent pathways are involved in the internalization of the prototypic TCP GKY25 in RAW264.7 and human monocyte-derived M1 macrophages, whereas the uptake of GKY25 in monocytic THP-1 cells is mainly dynamin-dependent. Internalized GKY25 was transported to endosomes and finally lysosomes, where it remained detectable for up to 10 h. Comparison of GKY25 uptake with that of the natural occurring TCPs HVF18 and FYT21 indicates that the pathway of TCP endocytosis is not only cell type-dependent but also depends on the length and composition of the peptide as well as the presence of LPS and bacteria. Finally, using neutron reflectometry, we show that the observed differences between HVF18 and the other 2 TCPs may be explained partially by differences in membrane insertion. Taken together, we show that TCPs are differentially internalized into monocytes and macrophages.

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Geographically Distinct Expression Profile of Host Defense Peptides in the Skin of the Chinese Odorous Frog, Odorrana margaretae

Asian Herpetological Research ◽

10.3724/sp.j.1245.2013.00288 ◽

2014 ◽

Vol 4 (4) ◽

pp. 288-297

Author(s):

LING Guiying ◽

LI Li ◽

GAO Jiuxiang ◽

YU Haining ◽

WANG Yipeng ◽

...

Keyword(s):

Host Defense ◽

Expression Profile ◽

Host Defense Peptides ◽

Defense Peptides

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Human Host Defense Peptides - Role in Maintaining Human Homeostasis and Pathological Processes

Current Medicinal Chemistry ◽

10.2174/0929867323666161213100443 ◽

2017 ◽

Vol 24 (7) ◽

pp. 654-672 ◽

Cited By ~ 2

Author(s):

Malgorzata Anna Dawgul ◽

Katarzyna E. Greber ◽

Wieslaw Sawicki ◽

Wojciech Kamysz

Keyword(s):

Host Defense ◽

Host Defense Peptides ◽

Human Host ◽

Defense Peptides

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Mechanistic Fingerprinting Reveals Kinetic Signatures of Resistance to Daptomycin and Host Defense Peptides in Streptococcus mitis-oralis

Antibiotics ◽

10.3390/antibiotics10040404 ◽

2021 ◽

Vol 10 (4) ◽

pp. 404

Author(s):

Michael R. Yeaman ◽

Liana C. Chan ◽

Nagendra N. Mishra ◽

Arnold S. Bayer

Keyword(s):

Flow Cytometry ◽

Host Defense ◽

Durable Resistance ◽

Cross Resistance ◽

Streptococcus Mitis ◽

Host Defense Peptides ◽

Strain Pair ◽

Defense Peptides

Streptococcus mitis-oralis (S. mitis-oralis) infections are increasingly prevalent in specific populations, including neutropenic cancer and endocarditis patients. S. mitis-oralis strains have a propensity to evolve rapid, high-level and durable resistance to daptomycin (DAP-R) in vitro and in vivo, although the mechanism(s) involved remain incompletely defined. We examined mechanisms of DAP-R versus cross-resistance to cationic host defense peptides (HDPs), using an isogenic S. mitis-oralis strain-pair: (i) DAP-susceptible (DAP-S) parental 351-WT (DAP MIC = 0.5 µg/mL), and its (ii) DAP-R variant 351-D10 (DAP MIC > 256 µg/mL). DAP binding was quantified by flow cytometry, in-parallel with temporal (1–4 h) killing by either DAP or comparative prototypic cationic HDPs (hNP-1; LL-37). Multicolor flow cytometry was used to determine kinetic cell responses associated with resistance or susceptibility to these molecules. While overall DAP binding was similar between strains, a significant subpopulation of 351-D10 cells hyper-accumulated DAP (>2–4-fold vs. 351-WT). Further, both DAP and hNP-1 induced cell membrane (CM) hyper-polarization in 351-WT, corresponding to significantly greater temporal DAP-killing (vs. 351-D10). No strain-specific differences in CM permeabilization, lipid turnover or regulated cell death were observed post-exposure to DAP, hNP-1 or LL-37. Thus, the adaptive energetics of the CM appear coupled to the outcomes of interactions of S. mitis-oralis with DAP and selected HDPs. In contrast, altered CM permeabilization, proposed as a major mechanism of action of both DAP and HDPs, did not differentiate DAP-S vs. DAP-R phenotypes in this S. mitis-oralis strain-pair.

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