A natural cell-penetrating nanopeptide combined with pentavalent antimonial as experimental therapy against cutaneous leishmaniasis

Targeting Leishmania Promastigotes and Amastigotes Forms through Amino Acids and Peptides: A Promising Therapeutic Strategy

Millions of people worldwide are affected by leishmaniasis, caused by the Leishmania parasite. Effective treatment is challenging due to the biological complexity of the parasite, drug toxicity, and increasing resistance to conventional drugs. To combat this disease, the development of specific strategies to target and selectively eliminate the parasite is crucial. This Review highlights the importance of amino acids in the developmental stages of Leishmania as a factor determining whether the infection progresses or is suppressed. It also explores the use of peptides as alternatives in parasite control and the development of novel targeted treatments. While these strategies show promise for more effective and targeted treatment, further studies to address the remaining challenges are imperative.

Unlocking the potential of snake venom-based molecules against the malaria, Chagas disease, and leishmaniasis triad

Malaria, leishmaniasis and Chagas disease are vector-borne protozoal infections with a disproportionately high impact on the most fragile societies in the world, and despite malaria-focused research gained momentum in the past two decades, both trypanosomiases and leishmaniases remain neglected tropical diseases. Affordable effective drugs remain the mainstay of tackling this burden, but toxicicty, inneficiency against later stage disease, and drug resistance issues are serious shortcomings. One strategy to overcome these hurdles is to get new therapeutics or inspiration in nature. Indeed, snake venoms have been recognized as valuable sources of biomacromolecules, like peptides and proteins, with antiprotozoal activity. This review highlights major snake venom components active against at least one of the three aforementioned diseases, which include phospholipases A2, metalloproteases, L-amino acid oxidases, lectins, and oligopeptides. The relevance of this repertoire of biomacromolecules and the bottlenecks in their clinical translation are discussed considering approaches that should increase the success rate in this arduous task. Overall, this review underlines how venom-derived biomacromolecules could lead to pioneering antiprotozoal treatments and how the drug landscape for neglected diseases may be revolutionized by a closer look at venoms. Further investigations on poorly studied venoms is needed and could add new therapeutics to the pipeline.

Leishmanicidal and immunomodulatory properties of Brazilian green propolis extract (EPP-AF®) and a gel formulation in a pre-clinical model

Leishmaniasis is a widespread group of neglected vector-borne tropical diseases that possess serious therapeutic limitations. Propolis has been extensively used in traditional medical applications due to its range of biological effects, including activity against infectious agents. Here we evaluated the leishmanicidal and immunomodulatory properties of Brazilian green propolis extract (EPP-AF^®) and a gel formulation incorporating EPP-AF^®, in both in vitro and in vivo models of Leishmania amazonensis infection. Propolis extract, obtained from a standardized blend following hydroalcoholic extraction, showed the characteristic fingerprint of Brazilian green propolis as confirmed by HPLC/DAD. A carbopol 940 gel formulation was obtained containing propolis glycolic extract at 3.6% w/w. The release profile, assessed using the Franz diffusion cell protocol, demonstrated a gradual and prolonged release of p-coumaric acid and artepillin C from the carbomer gel matrix. Quantification of p-coumaric acid and artepillin C in the gel formulation over time revealed that p-coumaric acid followed the Higuchi model, dependent on the disintegration of the pharmaceutical preparation, while artepillin C followed a zero-order profile with sustained release. In vitro analysis revealed the ability of EPP-AF^® to reduce the infection index of infected macrophages (p < 0.05), while also modulating the production of inflammatory biomarkers. Decreases in nitric oxide and prostaglandin E₂ levels were observed (p < 0.01), suggesting low iNOS and COX-2 activity. Furthermore, EPP-AF^® treatment was found to induce heme oxygenase-1 antioxidant enzyme expression in both uninfected and L. amazonensis-infected cells, as well as inhibit IL-1β production in infected cells (p < 0.01). ERK-1/2 phosphorylation was positively correlated with TNF-α production (p < 0.05), yet no impact on parasite load was detected. In vivo analysis indicated the effectiveness of topical treatment with EPP-AF^® gel alone (p < 0.05 and p < 0.01), or in combination with pentavalent antimony (p < 0.05 and p < 0.001), in the reduction of lesion size in the ears of L. amazonensis-infected BALB/c mice after seven or 3 weeks of treatment, respectively. Taken together, the present results reinforce the leishmanicidal and immunomodulatory effects of Brazilian green propolis, and demonstrate promising potential for the EPP-AF^® propolis gel formulation as a candidate for adjuvant therapy in the treatment of Cutaneous Leishmaniasis.

Antileishmanial activity, cytotoxicity and cellular response of amphotericin B in combination with crotamine derived from Crotalus durissus terrificus venom using in vitro and in silico approaches

OBJECTIVE

To investigate the in vitro activity, synergism, cytotoxicity and cellular immunological response, as well as the molecular affinity between amphotericin B (AmB) and crotamine (CTA), derived from Crotalus durissus terrificus venom against Leishmania amazonensis.

METHODS

This study performed the inhibition of promastigotes and amastigotes' growth under different concentrations of the drug and pharmacological combinations (AmB + CTA) based on the Berimbaum method (synergism study). The lactate dehydrogenase (LDH) quantification method was used to determine the cytotoxicity of the drug and combinations employing four cell lines (J774, HepG2, VERO, and C2C12). Following, the levels of Tumour Necrose Factor-alpha (TNF-α) and Interleukin-12 (IL-12) cytokines, using enzyme-linked immunosorbent assay (ELISA) and nitrites, as an indirect measure of Nitric Oxide (NO), using the Griess reaction were assessed in the supernatants of infected macrophages. In silico approach (molecular docking and dynamics) and binding affinity (surface plasmon resonance) between the drug and toxin were also investigated.

RESULTS

CTA enhanced AmB effect against promastigote and amastigote forms of L. amazonensis, decreased the drug toxicity in different cell lines and induced the production of important Th1-like cytokines and NO by infected macrophages. The pharmacological combination also displayed consistent molecular interactions with low energy of coupling and a concentration-dependent profile.

CONCLUSION

Our data suggest that this pharmacological approach is a promising alternative treatment against L. amazonensis infection due to the improved activity (synergistic effect) achieved against the parasites' forms and to the decreased cytotoxic effect.

Antitumor and antiparasitic activity of antimicrobial peptides derived from snake venom: a systematic review approach

BACKGROUND

In a scenario of increased pathogens with multidrug resistance phenotypes, it is necessary to seek new pharmacological options. This fact is responsible for an increase in neoplasms and multiresistant parasitic diseases. In turn, snake venom-derived peptides exhibited cytotoxic action on fungal and bacterial strains, possibly presenting activities in resistant tumor cells and parasites. Therefore, the aim of this work is to verify an antitumor and antiparasitic activity of antimicrobial peptides derived from snake venom.

METHODS

For this purpose, searches were performed in the Pubmed, Embase and Virtual Health Library databases by combining the descriptors peptides, venom and snake with antitumor/ antiparasitic agent and in silico. The inclusion criteria: in vitro and in vivo experimental articles in addition to in silico studies. The exclusion criteria: articles that were out of scope, review articles, abstracts, and letters to the reader. Data extracted: peptide name, peptide sequence, semi-maximal inhibitory concentration, snake species, tumor lineage or parasitic strain, cytotoxicity, in vitro and in vivo activity.

RESULTS

In total 164 articles were found, of which 14 were used. A total of ten peptides with antiproliferative activity on tumor cells were identified. Among the articles, seven peptides addressed the antiparasitic activity.

CONCLUSION

In conclusion, snake venom-derived peptides can be considered as potential pharmacological options for parasites and tumors, however more studies are needed to prove their specific activity.

Revisiting the potential of South American rattlesnake Crotalus durissus terrificus toxins as therapeutic, theranostic and/or biotechnological agents

The potential biotechnological and biomedical applications of the animal venom components are widely recognized. Indeed, many components have been used either as drugs or as templates/prototypes for the development of innovative pharmaceutical drugs, among which many are still used for the treatment of human diseases. A specific South American rattlesnake, named Crotalus durissus terrificus, shows a venom composition relatively simpler compared to any viper or other snake species belonging to the Crotalus genus, although presenting a set of toxins with high potential for the treatment of several still unmet human therapeutic needs, as reviewed in this work. In addition to the main toxin named crotoxin, which is under clinical trials studies for antitumoral therapy and which has also anti-inflammatory and immunosuppressive activities, other toxins from the C. d. terrificus venom are also being studied, aiming for a wide variety of therapeutic applications, including as antinociceptive, anti-inflammatory, antimicrobial, antifungal, antitumoral or antiparasitic agent, or as modulator of animal metabolism, fibrin sealant (fibrin glue), gene carrier or theranostic agent. Among these rattlesnake toxins, the most relevant, considering the potential clinical applications, are crotamine, crotalphine and gyroxin. In this narrative revision, we propose to organize and present briefly the updates in the accumulated knowledge on potential therapeutic applications of toxins collectively found exclusively in the venom of this specific South American rattlesnake, with the objective of contributing to increase the chances of success in the discovery of drugs based on toxins.