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Updated: Apr 18, 2026
Investigating Mast Cell Secretory Granules; from Biosynthesis to Exocytosis
Published on: January 26, 2015
Human-derived cathelicidin LL-37 directly activates mast cells to proinflammatory mediator synthesis and migratory
Edyta Bąbolewska1, Ewa Brzezińska-Błaszczyk1
1Department of Experimental Immunology, Medical University of Łódź, Pomorska 251, 92-213 Łódź, Poland.
Abstract:
Cathelicidins, a family of antimicrobial peptides, are well known for their role in host defense, particularly against bacteria. Apart from direct killing of microbes through the membrane disruption, cathelicidins can also exert immunomodulatory effects on cells involved in inflammatory processes. Considering the important role of mast cells in inflammation, the aim of this study was to determine whether LL-37, human-derived cathelicidin, can induce mast cell activation. We have observed that LL-37 directly stimulates mast cell to degranulation and production of some proinflammatory cytokines, but fails to induce cysteinyl leukotriene generation and release. We have also documented that LL-37 acts as a strong mast cell chemoattractant. In intracellular signaling in mast cells activated by LL-37 participates PLC/A2 and, in part, MAPKs, and PI3K. In conclusion, our results indicate that cathelicidins may enhance antibacterial inflammatory response via attracting mast cell to pathogen entry site and via induction of mast cell-derived mediator release.
Insights
Human cathelicidins like LL-37 activate mast cells, promoting inflammation. This antimicrobial peptide attracts mast cells to infection sites and triggers mediator release, enhancing the immune response against bacteria.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Cathelicidins are antimicrobial peptides crucial for host defense against bacteria.
- Beyond direct antimicrobial action, cathelicidins modulate inflammatory responses.
- Mast cells play a significant role in inflammatory processes.
Purpose of the Study:
- To investigate the effect of human cathelicidin LL-37 on mast cell activation.
- To determine if LL-37 induces mast cell degranulation, cytokine production, and chemoattraction.
Main Methods:
- Mast cell activation assays were performed.
- Cytokine production and leukotriene generation were measured.
- Intracellular signaling pathways (PLC/A2, MAPKs, PI3K) were analyzed.
Main Results:
- LL-37 directly stimulated mast cell degranulation and proinflammatory cytokine release.
- LL-37 did not induce cysteinyl leukotriene generation.
- LL-37 demonstrated strong chemoattractant properties for mast cells.
- Intracellular signaling involved PLC/A2, MAPKs, and PI3K.
Conclusions:
- LL-37 activates mast cells, contributing to inflammatory responses.
- Cathelicidins enhance antibacterial immunity by recruiting mast cells and inducing mediator release.
- LL-37's role in mast cell activation has implications for host defense mechanisms.
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