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  • 1
    Electronic Resource
    Electronic Resource
    143
HB-107, A Non-Antimicrobial Fragment of Cecropin B, Accelerates Murine Wound Repair (2004)
    Oxford, UK; Malden, USA : Blackwell Science Ltd/Inc.
    Wound repair and regeneration 12 (2004), S. 0 
    Details
    ISSN: 1524-475X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Intact skin represents the first line of defense against microbial pathogens. Effectors of innate immunity such as antimicrobial peptides are important when this barrier is breached due to infection or injury. Antimicrobial peptides can kill microbes directly, however several investigations have suggested they can also modify host cell behaviors to promote wound repair. It is unclear whether the ability of these molecules to positively influence wound repair is dependent on their antimicrobial function or on their ability to influence the host. To investigate this, the microbial killing capacity of specific antimicrobial peptide fragments was determined and compared with their ability to affect wound repair in a murine model of aseptic full-thickness excisional injury. HB-107, a peptide fragment derived from Cecropin B, lacks antimicrobial activity yet showed up to 64% improvement in wound closure at day13 when compared to either scrambled peptide or vehicle controls. This effect was comparable to that seen after treatment with currently accepted therapy. Histological evaluation of wounds treated with HB-107 displayed keratinocyte hyperplasia and increased leukocyte infiltration compared to controls. To explore the mechanism for these findings, we tested the ability of HB-107 to stimulate IL-8 secretion. HB-107 peptide was able to stimulate IL-8 release from cultured dermal microvascular endothelial cells when compared to scrambled peptide control or other peptides derived from Cecropin B. Taken together, this data confirms that antimicrobial peptides can function as important effectors of wound repair independent of antimicrobial function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1067-1927.2004.0abstractel.x
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of the expression and function of N-methyl-D-aspartate receptor in keratinocytes (2004)
    Oxford, UK; Malden, USA : Munksgaard International Publishers
    Experimental dermatology 13 (2004), S. 0 
    Details
    ISSN: 1600-0625
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract:  The N-methyl-D-aspartate (NMDA) receptor is expressed on neural tissue where it gates calcium ion entry upon stimulation. Using immunohistochemistry, it has been demonstrated in this study that the NMDAR1 receptor is also expressed on keratinocytes (KCs) in normal human skin and inflamed psoriatic skin in vivo. Furthermore, the NMDA receptor was functional as demonstrated by the ability of this receptor to trigger Ca++ influx in KCs. Incubation of cultured, human KCs with MK-801 decreases the cell growth and induces an increase in apoptosis. These findings demonstrate that the KC expression of NMDA receptor is a mechanism through which the influx of Ca++ into the cell can be regulated and suggest that the expression of this receptor may play a role in the regulation of KC growth and differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.0906-6705.2004.00186.x
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  • 3
    Electronic Resource
    Electronic Resource
    Biology of the Syndecans: A Family of Transmembrane Heparan Sulfate Proteoglycans (1992)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Cell and Developmental Biology 8 (1992), S. 365-393 
    Details
    ISSN: 0743-4634
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.cb.08.110192.002053
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  • 4
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    Endogenous Intracellular Cathelicidin Enhances TLR9 Activation in Dendritic Cells and Macrophages [INNATE IMMUNITY AND INFLAMMATION] (2015)
    The American Association of Immunologists (AAI)
    Details
    Publication Date: 2015-01-18
    Description: Cathelicidins are a gene family best known for their antimicrobial action, but the diverse mature peptides they encode also have other host defense functions. The human cathelicidin peptide LL-37 enhances recognition of nucleic acids, an action whose significance is seen in human diseases such as psoriasis where it is associated with increased type 1 IFN production. This function has been attributed to the extracellular action of the peptide to facilitate uptake of nucleic acids. In this study, we demonstrate that the murine mature cathelicidin peptide (CRAMP), encoded by the mouse gene ( Camp ), is functionally distinct from the human mature peptide (LL-37), as it does not facilitate CpG entry. However, mouse cathelicidin does influence recognition of CpG as bone marrow–derived dendritic cells from Camp –/– mice have impaired CpG responses and Camp –/– mice had impaired response to CpG given i.v. or s.c. We show that cathelicidin concentrates in Lamp1 positive compartments, is colocalized with CpG in the endolysosome, can be immunoprecipitated with TLR9, and binds to CpG intracellulary. Collectively, these results indicate that the functions of cathelicidin in control of TLR9 activation may include both intracellular and extracellular effects.
    Print ISSN: 0022-1767
    Electronic ISSN: 1550-6606
    Topics: Medicine
    Published by The American Association of Immunologists (AAI)
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  • 5
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    Neutrophil differentiation into a unique hybrid population exhibiting dual phenotype and functionality of neutrophils and dendritic cells (2013)
    American Society of Hematology (ASH)
    In: Blood
    Details
    Publication Date: 2013-03-08
    Description: Neutrophils have been reported to acquire surface expression of MHC class II and co-stimulatory molecules as well as T-cell stimulatory activities when cultured with selected cytokines. However, cellular identity of those unusual neutrophils showing antigen presenting cell (APC)-like features still remains elusive. Here we show that both immature and mature neutrophils purified from mouse bone marrow differentiate into a previously unrecognized "hybrid" population showing dual properties of both neutrophils and dendritic cells (DCs) when cultured with granulocyte macrophage-colony-stimulating factor but not with other tested growth factors. The resulting hybrid cells express markers of both neutrophils (Ly6G, CXCR2, and 7/4) and DCs (CD11c, MHC II, CD80, and CD86). They also exhibit several properties typically reserved for DCs, including dendritic morphology, probing motion, podosome formation, production of interleukin-12 and other cytokines, and presentation of various forms of foreign protein antigens to naïve CD4 T cells. Importantly, they retain intrinsic abilities of neutrophils to capture exogenous material, extrude neutrophil extracellular traps, and kill bacteria via cathelicidin production. Not only do our results reinforce the notion that neutrophils can acquire APC-like properties, they also unveil a unique differentiation pathway of neutrophils into neutrophil-DC hybrids that can participate in both innate and adaptive immune responses.
    Keywords: Immunobiology, Plenary Papers, Phagocytes, Granulocytes, and Myelopoiesis
    Print ISSN: 0006-4971
    Electronic ISSN: 1528-0020
    Topics: Biology , Medicine
    Published by American Society of Hematology (ASH)
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  • 6
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    LL-37 Induces AIF- and EndoG-Mediated Cell Death (2012)
    The American Association for Cancer Research (AACR)
    Details
    Publication Date: 2012-12-18
    Description: Cathelicidins are a family of bacteriocidal polypeptides secreted by macrophages and polymorphonuclear leukocytes (PMN). LL-37, the only human cathelicidin, has been implicated in tumorigenesis, but there has been limited investigation of its expression and function in cancer. Here, we report that LL-37 activates a p53-mediated, caspase-independent apoptotic cascade that contributes to suppression of colon cancer. LL-37 was expressed strongly in normal colon mucosa but downregulated in colon cancer tissues, where in both settings its expression correlated with terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling-positive apoptotic cells. Exposure of colon cancer cells to LL-37 induced phosphatidylserine externalization and DNA fragmentation in a manner independent of caspase activation. Apoptogenic function was mediated by nuclear translocation of the proapoptotic factors, apoptosis-inducing factor (AIF) and endonuclease G (EndoG), through p53-dependent upregulation of Bax and Bak and downregulation of Bcl-2 via a pertussis toxin–sensitive G-protein–coupled receptor (GPCR) pathway. Correspondingly, colonic mucosa of cathelicidin-deficient mice exhibited reduced expression of p53, Bax, and Bak and increased expression of Bcl-2 together with a lower basal level of apoptosis. Cathelicidin-deficient mice exhibited an increased susceptibility to azoxymethane-induced colon tumorigenesis, establishing pathophysiologic relevance in colon cancer. Collectively, our findings show that LL-37 activates a GPCR-p53-Bax/Bak/Bcl-2 signaling cascade that triggers AIF/EndoG–mediated apoptosis in colon cancer cells. Cancer Res; 72(24); 6512–23. ©2012 AACR.
    Print ISSN: 0008-5472
    Electronic ISSN: 1538-7445
    Topics: Medicine
    Published by The American Association for Cancer Research (AACR)
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  • 7
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    Streptokinase-activated Plasmin Degrades Cathelicidin AMPs [Immunology] (2012)
    The American Society for Biochemistry and Molecular Biology (ASBMB)
    Details
    Publication Date: 2012-12-01
    Description: The bacterial pathogen Group A Streptococcus (GAS) colonizes epithelial and mucosal surfaces and can cause a broad spectrum of human disease. Through the secreted plasminogen activator streptokinase (Ska), GAS activates human plasminogen into plasmin and binds it to the bacterial surface. The resulting surface plasmin protease activity has been proposed to play a role in disrupting tissue barriers, promoting invasive spread of the bacterium. We investigated whether this surface protease activity could aid the immune evasion role through degradation of the key innate antimicrobial peptide LL-37, the human cathelicidin. Cleavage products of plasmin-degraded LL-37 were analyzed by matrix-assisted laser desorption ionization mass spectrometry. Ska-deficient GAS strains were generated by targeted allelic exchange mutagenesis and confirmed to lack surface plasmin activity after growth in human plasma or media supplemented with plasminogen and fibrinogen. Loss of surface plasmin activity left GAS unable to efficiently degrade LL-37 and increased bacterial susceptibility to killing by the antimicrobial peptide. When mice infected with GAS were simultaneously treated with the plasmin inhibitor aprotinin, a significant reduction in the size of necrotic skin lesions was observed. Together these data reveal a novel immune evasion strategy of the human pathogen: co-opting the activity of a host protease to evade peptide-based innate host defenses.
    Print ISSN: 0021-9258
    Electronic ISSN: 1083-351X
    Topics: Biology , Chemistry and Pharmacology
    Published by The American Society for Biochemistry and Molecular Biology (ASBMB)
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  • 8
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    The antimicrobial peptide cathelicidin modulates Clostridium difficile-associated colitis and toxin A-mediated enteritis in mice (2013)
    BMJ Publishing Group
    In: Gut
    Details
    Publication Date: 2013-08-06
    Description: Background Clostridium difficile mediates intestinal inflammation by releasing toxin A (TxA), a potent enterotoxin. Cathelicidins ( Camp as gene name, LL-37 peptide in humans and mCRAMP peptide in mice) are antibacterial peptides that also posses anti-inflammatory properties. Objectives To determine the role of cathelicidins in models of Clostridium difficile infection and TxA-mediated ileal inflammation and cultured human primary monocytes. Design Wild-type (WT) and mCRAMP-deficient ( Camp –/– ) mice were treated with an antibiotic mixture and infected orally with C difficile . Some mice were intracolonically given mCRAMP daily for 3 days. Ileal loops were also prepared in WT mice and treated with either saline or TxA and incubated for 4 h, while some TxA-treated loops were injected with mCRAMP. Results Intracolonic mCRAMP administration to C difficile -infected WT mice showed significantly reduced colonic histology damage, apoptosis, tissue myeloperoxidase (MPO) and tumour necrosis factor (TNF)α levels. Ileal mCRAMP treatment also significantly reduced histology damage, tissue apoptosis, MPO and TNFα levels in TxA-exposed ileal loops. WT and Camp –/– mice exhibited similar intestinal responses in both models, implying that C difficile /TxA-induced endogenous cathelicidin may be insufficient to modulate C difficile /TxA-mediated intestinal inflammation. Both LL-37 and mCRAMP also significantly reduced TxA-induced TNFα secretion via inhibition of NF-B phosphorylation. Endogenous cathelicidin failed to control C difficile and/or toxin A-mediated inflammation and even intestinal cathelicidin expression was increased in humans and mice. Conclusion Exogenous cathelicidin modulates C difficile colitis by inhibiting TxA-associated intestinal inflammation. Cathelicidin administration may be a new anti-inflammatory treatment for C difficile toxin-associated disease.
    Keywords: Clostridium difficile
    Print ISSN: 0017-5749
    Electronic ISSN: 1468-3288
    Topics: Medicine
    Published by BMJ Publishing Group
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  • 9
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    S. aureus Subverts 2-O-Sulfated Domains in Syndecan-1 HS [Molecular Bases of Disease] (2015)
    The American Society for Biochemistry and Molecular Biology (ASBMB)
    Details
    Publication Date: 2015-06-27
    Description: Ablation of syndecan-1 in mice is a gain of function mutation that enables mice to significantly resist infection by several bacterial pathogens. Syndecan-1 shedding is induced by bacterial virulence factors, and inhibition of shedding attenuates bacterial virulence, whereas administration of purified syndecan-1 ectodomain enhances virulence, suggesting that bacteria subvert syndecan-1 ectodomains released by shedding for their pathogenesis. However, the pro-pathogenic functions of syndecan-1 ectodomain have yet to be clearly defined. Here, we examined how syndecan-1 ectodomain enhances Staphylococcus aureus virulence in injured mouse corneas. We found that syndecan-1 ectodomain promotes S. aureus corneal infection in an HS-dependent manner. Surprisingly, we found that this pro-pathogenic activity is dependent on 2-O-sulfated domains in HS, indicating that the effects of syndecan-1 ectodomain are structure-based. Our results also showed that purified syndecan-1 ectodomain and heparan compounds containing 2-O-sulfate motifs inhibit S. aureus killing by antimicrobial factors secreted by degranulated neutrophils, but does not affect intracellular phagocytic killing by neutrophils. Immunodepletion of antimicrobial factors with staphylocidal activities demonstrated that CRAMP, a cationic antimicrobial peptide, is primarily responsible for S. aureus killing among other factors secreted by degranulated neutrophils. Furthermore, we found that purified syndecan-1 ectodomain and heparan compounds containing 2-O-sulfate units potently and specifically inhibit S. aureus killing by synthetic CRAMP. These results provide compelling evidence that a specific subclass of sulfate groups, and not the overall charge of HS, permits syndecan-1 ectodomains to promote S. aureus corneal infection by inhibiting a key arm of neutrophil host defense.
    Print ISSN: 0021-9258
    Electronic ISSN: 1083-351X
    Topics: Biology , Chemistry and Pharmacology
    Published by The American Society for Biochemistry and Molecular Biology (ASBMB)
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  • 10
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    Cathelicidin-Related Antimicrobial Peptide Is Required for Effective Lung Mucosal Immunity in Gram-Negative Bacterial Pneumonia [HOST DEFENSE] (2012)
    The American Association of Immunologists (AAI)
    Details
    Publication Date: 2012-06-21
    Description: Cathelicidins are a family of endogenous antimicrobial peptides that exert diverse immune functions, including both direct bacterial killing and immunomodulatory effects. In this study, we examined the contribution of the murine cathelicidin, cathelicidin-related antimicrobial peptide (CRAMP), to innate mucosal immunity in a mouse model of Gram-negative pneumonia. CRAMP expression is induced in the lung in response to infection with Klebsiella pneumoniae . Mice deficient in the gene encoding CRAMP ( Cnlp –/– ) demonstrate impaired lung bacterial clearance, increased bacterial dissemination, and reduced survival in response to intratracheal K. pneumoniae administration. Neutrophil influx into the alveolar space during K. pneumoniae infection was delayed early but increased by 48 h in CRAMP-deficient mice, which was associated with enhanced expression of inflammatory cytokines and increased lung injury. Bone marrow chimera experiments indicated that CRAMP derived from bone marrow cells rather than structural cells was responsible for antimicrobial effects in the lung. Additionally, CRAMP exerted bactericidal activity against K. pneumoniae in vitro. Similar defects in lung bacterial clearance and delayed early neutrophil influx were observed in CRAMP-deficient mice infected with Pseudomonas aeruginosa , although this did not result in increased bacterial dissemination, increased lung injury, or changes in lethality. Taken together, our findings demonstrate that CRAMP is an important contributor to effective host mucosal immunity in the lung in response to Gram-negative bacterial pneumonia.
    Print ISSN: 0022-1767
    Electronic ISSN: 1550-6606
    Topics: Medicine
    Published by The American Association of Immunologists (AAI)
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