In vitro leishmanicidal activity of antimicrobial peptide KDEL against Leishmania tarentolae

Abstract

Leishmaniasis, caused by the intracellular protozoan parasite Leishmania, remains an important neglected tropical infectious disease. Infection may be lethal if untreated. Currently, the available drugs for the disease are limited by high toxicity and drug resistance. There is an urgent need to develop novel anti-leishmanial strategies. Antimicrobial peptides (AMPs) have been described as the first-line immune defense against pathogenic microbes and are being developed as emerging anti-parasitic therapies. In the present study, we showed the anti-leishmanial activity of the synthetic 4-amino acid peptide lysine, aspartic acid, glutamic acid, and leucine (KDEL), the endoplasmic reticulum retention sequence, against Leishmania tarentolae promastigote and amastigote. Different concentrations of KDEL peptides were incubated with promastigotes, MTT viability assay, and promastigote assay were carried out. Macrophages infected with GFP-transfected L. tarentolae promastigotes were incubated with KDEL peptides, and the anti-amastigote activity of the KDEL peptides was measured by fluorescence microscopy. The damage of L. tarentolae was observed by light microscopy and electron microscopy. The cell apoptosis was analyzed using the Annexin V-FITC/PI apoptosis detection kit and mitochondrial membrane potential assay kit and by flow cytometry. Results showed that L. tarentolae was susceptible to KDEL peptides in a dose-dependent manner, and KDEL peptides disrupted the surface membrane integrity and caused cell apoptosis. In our study, we found for the first time an AMP KDEL from Pseudomonas aeruginosa and proved its significant therapeutic potential as a novel anti-leishmanial drug.

Antimicrobial Peptides: Classification, Design, Application and Research Progress in Multiple Fields

“…In recent research, Epi-1, a marine synthetic AMP, can remarkably inhibit Trichomonas vaginalis by destroying its membrane (Neshani et al, 2019). The peptide Jellein derived from bee royal jelly which has introduced above and 4-amino acid AMP KDEL (lysine, aspartic acid, glutamic acid, and leucine) has shown a significant effect on the Leishmania parasite (Cao et al, 2019;Zahedifard et al, 2020). However, it should be noted that their mechanisms are not the same.…”

Peptides to Tackle Leishmaniasis: Current Status and Future Directions

“…Taking this into account, a box plot was constructed, as presented in Figure 3 . Since L. tropica promastigotes have only been tested with Temporin Shd (IC 50 = 13.9 µM) [ 54 ], and since L. tarentolae has only been used for the screening of the potential of KDEL peptide in both stages (with unknown IC 50 values) [ 55 ], these species were not included in the box plot. As for the remaining species, the activity ranges of the peptides vary between small values, on the order of nM, to values greater than 100 µM.…”

“…Several studies have explored the in vivo antileishmanial properties of peptides [ 42 , 48 , 55 , 60 , 64 , 78 , 79 , 80 , 81 ]. The preferred animal model for this type of analysis was the BALB/c mouse, as corroborated by the bibliometric map.…”

“…One of the most prominent examples of this group, given its nature, is the short peptide named after its amino acid sequence, KDEL, which presents a higher amount of negative amino acids (50%). This peptide is active against both life cycle stages of L. tarentolae (IC 50 not specified) [ 55 ]. Nevertheless, as generally observed for antimicrobial peptides, these negatively charged amino acids do not seem to contribute significantly to the peptides’ activity against Leishmania , and may even hamper the initial event of interaction with the parasite’s membrane.…”

Peptide-triggered IL-12 and IFN-γ mediated immune response in CD4+ T-cells against Leishmania donovani infection

“…25 Also, a tetramer peptide KDEL exhibited antileishmanial activity against Leishmania tarentolae promastigotes and amastigotes. 26 Intrigued by the enhanced proliferation potential of peptides 1 and 2 in the CFSE assay compared to other peptides, we conducted flow cytometry to quantitatively assess the rate of proliferation and proinflammatory cytokine (IL-12 and IFNg) producing abilities of Leishmania antigen activated, i.e., CD4 + CD44 + , T-cells. These cells were stimulated with LPS, SLA, and peptides, stained with CFSE for proliferation studies and fluorochrome labelled anti IL-12 and IFN-g antibodies.…”