Part:BBa_K3392001
LL-37
Cathelicidin peptide is a kind of peptide family protein which can inhibit the protease Cathepsin-L and has antimicrobial effect. Cathelicidin peptide is a kind of peptide family protein which can inhibit the protease cathepsin-l and has anti microbial effect.LL-37 may play an antibacterial role in Hp induced gastritis.
LL-37, known as hCAP18 as well, is the C-terminal part of the unique human cathelicidin identified to date named human cationic antimicrobial protein (hCAP).
LL-37 exhibits a variety of immunomodulatory functions such as bactericidal action, chemotaxis, activation of chemokine secretion and antisepsis effect [1].
The synthetic LL-37 peptide has been shown to suppress the inflammatory response induced by LPS and other TLR ligands [2].
Characterization with literatures
“Koji Hase draws the conclusions: H. pylori up-regulates production of LL-37/hCAP18 by gastric epithelium, which suggest this cathelicidin contributes to determining the balance between host mucosal defense and H. pylori survival mechanisms that govern chronic infection with this gastric pathogen.” Here are the results[3].
Figure 1. LL37/hCAP18 mRNA expression by human gastric epithelial cells infected with H. pylori. (A) AGS cells were left uninfected (control) or were infected with H. pylori SD4 strain. Expression of LL-37/hCAP18, hBD-2, and GAPDH mRNA was assessed by qualitative RT-PCR at 8 and 24 hours after infection. (B) LL-37/hCAP mRNA levels were analyzed by real-time PCR. Cells were infected with wild-type H. pylori SD4 (•), an isogenic ΔCagE mutant of SD4 (▵), or left uninfected (○). LL-37/hCAP18 mRNA levels, normalized to those of GAPDH, are expressed as fold increase over uninfected controls at time 0. Data are from a representative experiment. Values are mean ± SD, n = 3; ∗P < 0.05. Similar results were obtained in 2 repeated experiments.
Figure 2. Antimicrobial activity of LL-37. (A) H. pylori SD14 were incubated in the presence of the indicated concentrations of LL-37 for 6 hours, after which CFU were determined. (B) H. pylori SD14 was cultured for the indicated times in the absence (○) or presence (•) of LL-37 (16 μmol/L). Values both panels are mean ± SD, n = 4. Results in both panels are from single representative experiments. Similar results were obtained in 2 or more repeated experiments.
Figure 3. Antimicrobial activity of LL-37, hBD-1, and hBD-2. (A) H. pylori SD4 (solid bars) or E. coli O29:NM (open bars) were incubated with or without LL-37, hBD-1, or hBD-2 (each at 16 μmol/L) for 6 hours, after which CFU were determined. Values are mean ± SD, n = 4; P < 0.05 compared to control. Results are from a single experiment. Similar results were obtained in an additional repeated experiment. (B) H. pylori strain 26695 was left untreated or cultured with LL-37 (16 μmol/L), hBD-1 (16 μmol/L), or LL-37 in combination with hBD-1 for 6 hours. Values are mean ± SD, n = 4; ∗P < 0.05 compared with control and hBD-1 alone; ∗∗P < 0.05 compared to LL-37 alone. Results are from a single experiment. Similar results were obtained in an additional repeated experiment.
According to the above data, it can be proved that LL-37, as an antimicrobial peptide produced by human body, is an effective molecular drug to kill and inhibit Helicobacter pylori. Our use of LL-37 in this year's project to inhibit the growth of Helicobacter pylori is well founded.
References
[1] Scott MG. et al., 2002. The human antimicrobial peptide LL-37 is a multifunctional modulator of innate immune responses. J Immunol. 169(7):3883-91.
[2] Mookherjee N. et al., 2006. Modulation of theTLR-mediated inflammatory response by the endogenous human host defense peptide LL-37. J Immunol. 176(4):2455-64.
[11] Koji Hase, Masamoto Murakami, Mitsutoshi Iimura, et al. Expression of LL-37 by human gastric epithelial cells as a potential host defense mechanism against Helicobacter pylori. 2003, 125(6):1613-1625.
Sequence and Features
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- 21INCOMPATIBLE WITH RFC[21]Illegal XhoI site found at 112
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
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