Anti-parasitic effect of the diuretic and Na+-ATPAse inhibitor furosemide in cutaneous leishmaniasis

Inhibition of Giardia duodenalis by isocryptolepine -triazole adducts and derivatives

Giardia duodenalis, a widespread parasitic flagellate protozoan causing giardiasis, affects millions annually, particularly impacting children and travellers. With no effective vaccine available, treatment primarily relies on the oral administration of drugs targeting trophozoites in the small intestine. However, existing medications pose challenges due to side effects and drug resistance, necessitating the exploration of novel therapeutic options. Isocryptolepine, derived from Cryptolepis sanguinolenta, has demonstrated promising antimicrobial and anticancer properties. This study evaluated eighteen isocryptolepine-triazole adducts for their antigiardial activities and cytotoxicity, with ISO2 demonstrating potent antigiardial activity and minimal cytotoxicity on human intestinal cells. Metabolomics analysis revealed significant alterations in G. duodenalis metabolism upon ISO2 treatment, particularly affecting phospholipid metabolism. Notably, the upregulation of phytosphingosine and triglycerides, and downregulation of certain fatty acids, suggest a profound impact on membrane composition and integrity, potentially contributing to the parasite's demise. Pathway analysis highlighted glycerophospholipid metabolism, cytochrome b5 family heme/steroid binding domain, and P-type ATPase mechanisms as critical pathways affected by ISO2 treatment, underscoring its importance as a potential target for antigiardial therapy. These findings shed light on the mode of action of ISO2 against G. duodenalis and provide valuable insights for further drug development. Moreover, the study also offers a promising avenue for the exploration of isocryptolepine derivatives as novel therapeutic agents for giardiasis, addressing the urgent need for more effective and safer treatment options.

Cutaneous leishmaniasis: new oral therapeutic approaches under development

The World Health Organization (WHO) classifies leishmaniasis as a disease for which the development of new treatments is a priority. Available drugs are not fully effective in all cases; they have parenteral administration and exhibit serious and common adverse effects. The only oral drug available (miltefosine) has shown resistance, is expensive, and is not available in many endemic countries. Thus, the development of an oral medicine may solve many of these issues. Based on that, this review aimed to investigate which therapeutic alternatives have been studied for the development of oral drugs for the treatment of cutaneous leishmaniasis. A literature search for keywords "leishmania and oral" was performed in PubMed and ScienceDirect, considering articles published in the last 5 years. The articles were selected based on the objective of the review. The main problem in the current treatment of leishmaniasis is the administration of injectables, since it requires patients to travel to health centers, hospitalization, and professional administration, conditions that are not adapted to the socioeconomic reality of patients. Therefore, many research studies have evaluated oral alternatives for the treatment of cutaneous leishmaniasis. The main tested approaches were obtaining new molecules, repositioning drugs, and new formulations of old drugs. The prospects are encouraging but still require more in vivo bioavailability and clinical trials.

The Functioning of Na+-ATPases from Protozoan Parasites: Are These Pumps Targets for Antiparasitic Drugs?

The ENA ATPases (from exitus natru: the exit of sodium) belonging to the P-type ATPases are structurally very similar to the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA); they exchange Na+ for H+ and, therefore, are also known as Na+-ATPases. ENA ATPases are required in alkaline milieu, as in the case for Aspergillus, where other transporters cannot mediate an uphill Na+ efflux. They are also important for salt tolerance, as described for Arabidopsis. During their life cycles, protozoan parasites might encounter a high pH environment, thus allowing consideration of ENA ATPases as possible targets for controlling certain severe parasitic diseases, such as Chagas' Disease. Phylogenetic analysis has now shown that, besides the types IIA, IIB, IIC, and IID P-type ATPases, there exists a 5th subgroup of ATPases classified as ATP4-type ATPases, found in Plasmodium falciparum and Toxoplasma gondii. In malaria, for example, some drugs targeting PfATP4 destroy Na+ homeostasis; these drugs, which include spiroindolones, are now in clinical trials. The ENA P-type (IID P-type ATPase) and ATP4-type ATPases have no structural homologue in mammalian cells, appearing only in fungi, plants, and protozoan parasites, e.g., Trypanosoma cruzi, Leishmania sp., Toxoplasma gondii, and Plasmodium falciparum. This exclusivity makes Na+-ATPase a potential candidate for the biologically-based design of new therapeutic interventions; for this reason, Na+-ATPases deserves more attention.

P-type transport ATPases in Leishmania and Trypanosoma

P-type ATPases are critical to the maintenance and regulation of cellular ion homeostasis and membrane lipid asymmetry due to their ability to move ions and phospholipids against a concentration gradient by utilizing the energy of ATP hydrolysis. P-type ATPases are particularly relevant in human pathogenic trypanosomatids which are exposed to abrupt and dramatic changes in their external environment during their life cycles. This review describes the complete inventory of ion-motive, P-type ATPase genes in the human pathogenic Trypanosomatidae; eight Leishmania species (L. aethiopica, L. braziliensis, L. donovani, L. infantum, L. major, L. mexicana, L. panamensis, L. tropica), Trypanosoma cruzi and three Trypanosoma brucei subspecies (Trypanosoma brucei brucei TREU927, Trypanosoma brucei Lister strain 427, Trypanosoma brucei gambiense DAL972). The P-type ATPase complement in these trypanosomatids includes the P_1B (metal pumps), P_2A (SERCA, sarcoplasmic-endoplasmic reticulum calcium ATPases), P_2B (PMCA, plasma membrane calcium ATPases), P_2D (Na⁺ pumps), P_3A (H⁺ pumps), P₄ (aminophospholipid translocators), and P_5B (no assigned specificity) subfamilies. These subfamilies represent the P-type ATPase transport functions necessary for survival in the Trypanosomatidae as P-type ATPases for each of these seven subfamilies are found in all Leishmania and Trypanosoma species included in this analysis. These P-type ATPase subfamilies are correlated with current molecular and biochemical knowledge of their function in trypanosomatid growth, adaptation, infectivity, and survival.