Repurposing the Antibacterial Agents Peptide 19-4LF and Peptide 19-2.5 for Treatment of Cutaneous Leishmaniasis

Abstract

The lack of safe and cost-effective treatments against leishmaniasis highlights the urgent need to develop improved leishmanicidal agents. Antimicrobial peptides (AMPs) are an emerging category of therapeutics exerting a wide range of biological activities such as anti-bacterial, anti-fungal, anti-parasitic and anti-tumoral. In the present study, the approach of repurposing AMPs as antileishmanial drugs was applied. The leishmanicidal activity of two synthetic anti-lipopolysaccharide peptides (SALPs), so-called 19-2.5 and 19-4LF was characterized in Leishmania major. In vitro, both peptides were highly active against intracellular Leishmania major in mouse macrophages without exerting toxicity in host cells. Then, q-PCR-based gene profiling, revealed that this activity was related to the downregulation of several genes involved in drug resistance (yip1), virulence (gp63) and parasite proliferation (Cyclin 1 and Cyclin 6). Importantly, the treatment of BALB/c mice with any of the two AMPs caused a significant reduction in L. major infective burden. This effect was associated with an increase in Th1 cytokine levels (IL-12p35, TNF-α, and iNOS) in the skin lesion and spleen of the L. major infected mice while the Th2-associated genes were downregulated (IL-4 and IL-6). Lastly, we investigated the effect of both peptides in the gene expression profile of the P2X7 purinergic receptor, which has been reported as a therapeutic target in several diseases. The results showed significant repression of P2X7R by both peptides in the skin lesion of L. major infected mice to an extent comparable to that of a common anti-leishmanial drug, Paromomycin. Our in vitro and in vivo studies suggest that the synthetic AMPs 19-2.5 and 19-4LF are promising candidates for leishmaniasis treatment and present P2X7R as a potential therapeutic target in cutaneous leishmaniasis (CL).

Neglected Zoonotic Diseases: Advances in the Development of Cell-Penetrating and Antimicrobial Peptides against Leishmaniosis and Chagas

“…In recent years, the synergistic effect of leishmanicidal drugs with AMPs has been analyzed. For instance, the combination of synthetic anti-lipopolysaccharide peptides (SALPs), 19-2.5 and 19-4LF with the paromomycin and AmB enhanced their activity against L. major amastigotes in vitro [67]. Conversely, this synergistic effect was not observed when modified halictine-2-derived peptide was employed in combination with those leishmanicidal treatments.…”

“…An important advantage of AMPs is their broad potential for synthetic modification. The molecular characterization of AMPs makes it possible to generate synthetic derivatives by modification of the primary sequence in order to improve some sides related to target specificity, cytotoxicity, potency, stability, or the active site [53,54,67,70,71,86]. This flexibility could enable the development of AMPs with optimized therapeutic properties for the treatment of both diseases.…”

“…The first reports of the effects of AMPs on Leishmania were published in 1998, with Hyalophora (both) cecropin A [92] and cecropin A (1-8)-melittin (1-18) (CAMEL) hybrid peptides [93] and components of the target microorganisms, such as macromolecules and organelles [41,94]. To date, several groups of AMPs and CPPs, such as cathelicidins, cecropins, defensins, dermaseptins, eumenitins, histatins, magainins, melittins, and temporins, among others, have been proven to have significant action against diverse Leishmania species [67,91]. In this sense, relevant reviews have been published in recent decades [8,79], highlighting this group as an exciting alternative for designing new pharmaceutical alternatives against leishmaniosis and making evident the growing list of AMP and CPPs with antileishmanial activity [8].…”

“…Just like paromomycin induces protein synthesis inhibition in L. donovani promastigotes [62], it has been hypothesized that xenocoumacin acts similarly on L. tropica promastigotes [111]. Recently, the modulatory effect of AMPs on L. major amastigote gene expression was shown as an additional mechanism [67]. The induction of autophagic cell death in the protozoan pathogen L. donovani has been described, as an AMP mode of action, Indolicidin, and two peptides derived from Seminalplasmin (SPK and 27RP), prompt programmed cell death pathways without affecting host cells [112].…”

In vitro and in vivo antileishmanial activity of thioridazine

“…Current antileishmanial drugs including miltefosine (primarily developed as anticancer drug), amphotericin B (antifungal drug), pentamidine (antifungal -treatment of pneumonia caused by Pneumocystis jiroveci) and paromomycin (antibiotic), together with others that have demonstrated antileishmanial activity at experimental level [8][9][10], support the potential of drug repositioning for leishmaniasis.…”