LL-37 (5mg)

LL-37 Peptide

LL-37, also known as Cathelicidin, is a cationic peptide composed of 37 amino acids, and is primarily found in neutrophils.⁽¹⁾ LL-37 appears to be produced by the extracellular breakdown of the hCAP18 proteins caused by protease enzymes. Researched for its potential antimicrobial properties, the peptide appears to form agglomerates and lipid bilayers, due to which it may not easily degrade, and may be protected from enzymatic action.⁽¹⁾

Overview

Antimicrobial peptides are structured with the potential to fight against bacteria, fungi, and some virus strains. These peptides may interact with targets in a non-specific fashion, which supports researchers' belief that once the peptide is introduced, pathogens are unable to develop resistance against these peptides.⁽²⁾

LL-37 is a α-helical peptide that scientists believe is required to maintain immunity against all microbes.⁽³⁾ To understand the functioning of the peptide, a peptide model was created as part of a study⁽⁴⁾ based on the assumption that the peptide has the potential to interact directly with the bacterial membrane. This study suggested that the peptide first interacts with the lipids on the bacterial membrane via electrostatic characteristics, followed by lateral diffusion and consequent assembly of the peptide on the membrane. This potential interaction would lead to membrane interference and degradation of the bacterial cell.

There are several other studies that hypothesize how the peptide interacts with microbial membranes, including pore formation on the membrane⁽³⁾⁽⁵⁾ and extreme membrane disruption caused by the peptide and lipid complexes.⁽⁶⁾ These studies universally suggest that peptides have the potential to interact with the microbial membrane leading the membrane breakdown.
 

Research and Clinical Studies

LL-37 Peptide and Inflammatory Response

The main aim of this study⁽⁷⁾ was to determine the inflammatory potential of this peptide. Tissue culture was used, half of which was used without alteration and to the other half, with added U1 RNA. U1 RNA is a non-coding RNA found in abundance in the body and is apparently released upon tissue injury. LL-37 peptide was then added to both cultures. Upon genetic analysis, it was suggested by the researchers that the culture that was given both U1 RNA and LL-37 peptide exhibited a reportedly significant response towards epidermal (skin) inflammation and defense response.

LL-37 Peptide and Psoriasis

The main aim of this study⁽¹⁾ was to understand the role of LL-37 in psoriasis. This disease pathogenesis study suggested that endogenous LL-37 peptide may form complex DNA which may lead to increased interferon mechanism and more inflammatory responses. This study theorized that LL-37 may be favorable for tissue and wound injury, however, in some cases, LL-37 levels appeared to be indicative of psoriasis presence.

LL-37 Peptide and Arthritis

The main objective of this study⁽¹⁾⁽⁸⁾ was to evaluate the potential of LL-37 in arthritic joints. A group of rats were used in this study⁽⁸⁾ with one control group and one group experimentally induced with rheumatoid arthritis. Upon inducing the condition, researchers reported there was an apparent increased regulation of rCRAMP, which is the rat analog of LL-37 peptide, in inflammatory cells. Researchers suggested that LL-37 peptide might further induce apoptosis of osteoblasts, thereby leading to decreased bone formation in the joints. This study suggested that increased LL-37 levels are characteristic to joint ache and arthritis and may potentially be used for diagnostic purposes.

Besides these, study⁽¹⁾ has suggested the LL-37 elevation is seen in other inflammatory circumstances, such as arteriosclerosis. LL-37 activation and the consequent upregulation of interferons are reported by scientists to be characteristic to arteriosclerosis induced cells. The researchers of this study suggested that LL-37 may have potential as an immunomodulatory agent.

LL-37 Peptide and Tissue Repair

In this study,⁽⁹⁾ mice presented with an anti-inflammatory compound were then presented with LL-37 to study the potention of this peptide on angiogenesis and wound healing. It was suggested by the researchers that the peptide mice exhibited an apparent increase in results of vascularization and formation of skin cells. This study suggested that LL-37 has the potential to induce endothelial skin cell proliferation and formation of tubule-like structures, which are both required in angiogenesis mechanisms.

LL-37 Peptide and Cancer Cells

Studies⁽¹⁰⁾ are ongoing to explore the potential of the peptide in cancer cell development. Studies⁽¹⁰⁾ have suggested that LL-37 may inhibit gastric cancer cell proliferation by way of activation of bone morphogenetic protein signaling system. The main aim of this research⁽¹⁰⁾ was to consider the potential of LL-37 as an immunotherapeutic agent, or consider the potential of LL-37 peptide as an adjuvant in eliminating cancer cells from the host system. CpG oligodeoxynucleotides are widely considered to be immunotherapeutic agents as it appears to promote the tumor suppressing activities in the body. When presented with LL-37, researchers reported that the peptide LL-37 appeared to increase the CpG oligodeoxynucleotides sensitivity in lymphocytes.

LL-37 Peptide and GI Tract

LL-37 may have the potential to impact ailments associated with the gastrointestinal (GI) tract. There appears to be an increased expression of LL-37 in the subjects with stomach ulcers. Owing to its antimicrobial potential, LL-37 may have the capability to protect stomach and GI mucosa from microbial damage.⁽¹²⁾

LL-37 peptide is available for research and laboratory purposes only. Please review and adhere to our Terms and Conditions before ordering.

References:

1. Kahlenberg, J Michelle, and Mariana J Kaplan. “Little peptide, big effects: the role of LL-37 in inflammation and autoimmune disease.” Journal of immunology (Baltimore, Md. : 1950) vol. 191,10 (2013): 4895-901. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3836506/
2. Seil, M., Nagant, C., Dehaye, J. P., Vandenbranden, M., & Lensink, M. F. (2010). Spotlight on Human LL-37, an Immunomodulatory Peptide with Promising Cell-Penetrating Properties. Pharmaceuticals, 3(11), 3435–3460. h https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4034075/
3. Zeth, Kornelius, and Enea Sancho-Vaello. “The Human Antimicrobial Peptides Dermcidin and LL-37 Show Novel Distinct Pathways in Membrane Interactions.” Frontiers in chemistry vol. 5 86. 7 Nov. 2017. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5681987/
4. Brogden KA. Antimicrobial peptides: pore formers or metabolic inhibitors in bacteria? Nat Rev Microbiol. 2005 Mar;3(3):238-50. https://pubmed.ncbi.nlm.nih.gov/15703760/
5. Ludtke SJ, He K, Heller WT, Harroun TA, Yang L, Huang HW. Membrane pores induced by magainin. Biochemistry. 1996 Oct 29;35(43):13723-8. https://pubmed.ncbi.nlm.nih.gov/8901513/
6. Bechinger B, Lohner K. Detergent-like actions of linear amphipathic cationic antimicrobial peptides. Biochim Biophys Acta. 2006 Sep;1758(9):1529-39. https://pubmed.ncbi.nlm.nih.gov/16928357/
7. Takahashi, T., Kulkarni, N.N., Lee, E.Y. et al. Cathelicidin promotes inflammation by enabling binding of self-RNA to cell surface scavenger receptors. Sci Rep 8, 4032 (2018). https://doi.org/10.1038/s41598-018-22409-3
8. Hoffmann MH, Bruns H, Bäckdahl L, Neregård P, Niederreiter B, Herrmann M, Catrina AI, Agerberth B, Holmdahl R. The cathelicidins LL-37 and rCRAMP are associated with pathogenic events of arthritis in humans and rats. Ann Rheum Dis. 2013 Jul;72(7): https://pubmed.ncbi.nlm.nih.gov/23172753/
9. Ramos R, Silva JP, Rodrigues AC, Costa R, Guardão L, Schmitt F, Soares R, Vilanova M, Domingues L, Gama M. Wound healing activity of the human antimicrobial peptide LL37. Peptides. 2011 Jul;32(7):1469-76. doi: 10.1016/j.peptides.2011.06.005. Epub 2011 Jun 13. https://pubmed.ncbi.nlm.nih.gov/21693141/
10. Wu, W. K., Wang, G., Coffelt, S. B., Betancourt, A. M., Lee, C. W., Fan, D., Wu, K., Yu, J., Sung, J. J., & Cho, C. H. (2010). Emerging roles of the host defense peptide LL-37 in human cancer and its potential therapeutic applications. International journal of cancer, 127(8), 1741–1747. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2930073/
11. Wang, C., Wang, S., Li, D., Chen, P., Han, S., Zhao, G., Chen, Y., Zhao, J., Xiong, J., Qiu, J., Wei, D. Q., Zhao, J., & Wang, J. (2021). Human Cathelicidin Inhibits SARS-CoV-2 Infection: Killing Two Birds with One Stone. ACS infectious diseases, 7(6), 1545–1554. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8056948/
12. Kusaka; et al. Expression of human cathelicidin peptide LL-37 in inflammatory bowel disease. Clin Exp Immunol. 2018 Jan;19(11). Epub 2017 Sep 28. https://pubmed.ncbi.nlm.nih.gov/28872665/