Introduction
LL-37 is the only known human cathelicidin-derived antimicrobial peptide, encoded by the CAMP gene and expressed in neutrophils, epithelial cells, and other immune-related tissues. It plays critical roles in host defense, immune regulation, wound healing, and cancer biology. This article summarizes current scientific research on LL-37, highlighting its potential utility in laboratory studies.
1. Antimicrobial Activity
LL-37 demonstrates broad-spectrum antimicrobial effects against Gram-positive and Gram-negative bacteria, viruses, and fungi. Its mechanism involves disrupting microbial membranes via electrostatic interactions and pore formation, leading to cell lysis. LL-37 also inhibits biofilm formation and can degrade established biofilms—an important feature for studying persistent infections [1].
2. Immunomodulatory Functions
LL-37 modulates both innate and adaptive immune responses. It serves as a chemoattractant for neutrophils, monocytes, and T-cells through FPRL1 receptor signaling and enhances pro-inflammatory cytokine production (e.g., IL-6, TNF-α, IL-8), while in some contexts, it exhibits anti-inflammatory behavior [2].
3. Role in Wound Healing
Research has shown LL-37 supports re-epithelialization by stimulating keratinocyte proliferation and migration—key processes in wound repair. Additionally, LL-37 promotes angiogenesis, facilitating vascular support in healing tissue [3].
4. Cancer Research Applications
LL-37 has a dual role in cancer. In some models, it promotes tumor progression by enhancing cancer cell proliferation and migration (e.g., in ovarian and lung cancers). In others, it demonstrates anti-tumor properties by inducing apoptosis and suppressing tumor growth [4].
5. Stability and Peptide Engineering
LL-37 is prone to proteolytic degradation, limiting its in vivo stability. To address this, researchers have created analogs and cyclized derivatives that retain antimicrobial function while increasing resistance to enzymatic breakdown [5].
Conclusion
LL-37 is a promising peptide with broad research implications in immunology, microbiology, dermatology, and oncology. Continued studies on its mechanisms and peptide analogs may enhance its viability for experimental applications.
References
- Wang, G. (2021). LL-37: Structures, Antimicrobial Activity, and Influence on Amyloid Formation. International Journal of Molecular Sciences, 22(23), 12803. Link
- Kahlenberg, J.M., & Kaplan, M.J. (2013). Little peptide, big effects: the role of LL-37 in inflammation and autoimmune disease. The Journal of Immunology, 191(10), 4895–4901. Link
- Heilborn, J.D., et al. (2003). The cathelicidin antimicrobial peptide LL-37 is involved in re-epithelialization of human skin wounds. J Invest Dermatol, 120(3), 379–389. Link
- Kuroda, K., et al. (2012). The human cathelicidin antimicrobial peptide LL-37 and mimics are potential anticancer drugs. Frontiers in Oncology, 2:194. Link
- Svensson, D., & Malmsten, M. (2022). A stable cyclized antimicrobial peptide derived from LL-37 with host defense properties. Biomolecules, 12(8), 1106. Link
Disclaimer
This article is provided strictly for research and educational purposes only. LL-37 is an investigational peptide not approved for human consumption, therapeutic use, or diagnostic application. Handle according to institutional safety and regulatory guidelines.