Induction of Autophagy by Ursolic Acid Promotes the Elimination of Trypanosoma cruzi Amastigotes From Macrophages and Cardiac Cells

Cationic and anionic PLGA-cholesterol hybrid nanoparticles as promising platforms to enhance the trypanocidal efficacy of benznidazole and drug delivery in Trypanosoma cruzi-infected cells

Chagas disease is a neglected tropical disease caused by the protozoan Trypanosoma cruzi, remains a significant global health challenge. Currently, benznidazole (BNZ) is the primary treatment in many countries. However, this drug is limited by low bioavailability, significant host toxicity, and reduced efficacy in chronic disease phase. Additionally, cases of parasite resistance to treatment and low efficacy in in chronic disease phase have been reported. In this context, nanotechnology formulations for intracellular drug delivery have emerged as a promising alternative to improve the pharmacological properties of BNZ. In this study, we developed and evaluated cationic and anionic PLGA-cholesterol hybrid nanoparticles (HNPs) as innovative drug delivery systems for BNZ. These HNPs, functionalized with polyethyleneimine, were synthesized using a composition-dependent self-assembly method, yielding stable nanosystems with tuneable physicochemical properties. Furthermore, four release kinetic models were applied and Peppas-Sahlin demonstrated the best fit. In vitro assays confirmed the biocompatibility of HNPs with cardiomyoblasts at tested concentrations and revealed significantly enhanced trypanocidal activity against intracellular amastigotes compared to free BNZ. Transmission electron microscopy and fluorescence microscopy analyses highlighted effective nanoparticle internalization, with superior performance trypanocidal observed in anionic HNPs, which can be attributed to the residence of cationic in endo/lysosomal vesicles. Taken together, our results demonstrate the successful development of HNPs, underscoring their potential as a promising platform for the intracellular delivery of therapeutic agents.

Benzaldehyde stimulates autophagy via the sonic hedgehog signaling pathway in mouse brain astrocytes after treatment with Angiostrongylus cantonensis excretory-secretory products

Autophagy is a vital cellular process responsible for digesting various cytoplasmic organelles. This process plays a crucial role in maintaining cell survival and homeostasis, especially under conditions that cause nutrient deficiency, cellular damage, and oxidative stress. Neuroangiostrongyliasis is an infection caused by the parasitic nematode Angiostrongylus cantonensis and is considered as an emerging disease in many parts of the world. However, effective therapeutic strategies for neuroangiostrongyliasis still need to be further developed. In this study, we investigated the effects of benzaldehyde treatment on autophagy and sonic hedgehog (Shh) signaling in A. cantonensis-infected mice and its mechanisms. First, we found autophagosome generation in the central nervous system after A. cantonensis infection. Next, benzaldehyde combined with albendazole treatment reduced eosinophilic meningitis and upregulated the expression of Shh signaling- and autophagy-related molecules in A. cantonensis-infected mouse brains. In vitro experiments demonstrated that benzaldehyde could induce autophagy via the Shh signaling pathway in A. cantonensis excretory-secretory products (ESPs)-treated mouse astrocytes. Finally, benzaldehyde treatment also decreased lipid droplet accumulation and increased cholesterol production by activating the Shh pathway after ESPs treatment. In conclusion, these findings suggested that benzaldehyde treatment could alleviate brain damage by stimulating autophagy generation through the Shh signaling pathway.

Euphane and Tirucallane Triterpenes with Trypanocidal Activity from Euphorbia desmondii

The phytochemical investigation of Euphorbia desmondii resulted in the isolation of 15 previously undescribed triterpenoids (desmondiins A, C-P) and 8 already described compounds. The structures of the isolated compounds were determined by extensive spectroscopic analyses. The compounds were identified as tirucallane and euphane triterpenes based on 7-keto-8-ene, 11-keto-8-ene, or 7,11-diketo-8-ene skeletons. Additionally, the selective trypanocidal activities of these compounds against Trypanosoma cruzi were evaluated. Desmondiins A, C, D, F, H, and M exhibited IC50 values in the range of 3-5 μM, and selectivity indices between 5-9, against T. cruzi epimastigotes over the host cell (RAW264.7 macrophages). Furthermore, desmondiin A efficiently inhibited amastigote replication in host cells (IC50 = 2.5 ± 0.3 μM), which was comparable to that of the positive control, benznidazole (3.6 ± 0.4 μM). Overall, the isolated euphane and tirucallane triterpenoids could act as antichagasic lead scaffolds.

Autophagy as an innate immunity response against pathogens: a Tango dance

Intracellular infections as well as changes in the cell nutritional environment are main events that trigger cellular stress responses. One crucial cell response to stress conditions is autophagy. During the last 30 years, several scenarios involving autophagy induction or inhibition over the course of an intracellular invasion by pathogens have been uncovered. In this review, we will present how this knowledge was gained by studying different microorganisms. We intend to discuss how the cell, via autophagy, tries to repel these attacks with the objective of destroying the intruder, but also how some pathogens have developed strategies to subvert this. These two fates can be compared with a Tango, a dance originated in Buenos Aires, Argentina, in which the partner dancers are in close connection. One of them is the leader, embracing and involving the partner, but the follower may respond escaping from the leader. This joint dance is indeed highly synchronized and controlled, perfectly reflecting the interaction between autophagy and microorganism.

From Benznidazole to New Drugs: Nanotechnology Contribution in Chagas Disease

Chagas disease is a neglected tropical disease caused by the protozoan Trypanosoma cruzi. Benznidazole and nifurtimox are the two approved drugs for their treatment, but both drugs present side effects and efficacy problems, especially in the chronic phase of this disease. Therefore, new molecules have been tested with promising results aiming for strategic targeting action against T. cruzi. Several studies involve in vitro screening, but a considerable number of in vivo studies describe drug bioavailability increment, drug stability, toxicity assessment, and mainly the efficacy of new drugs and formulations. In this context, new drug delivery systems, such as nanotechnology systems, have been developed for these purposes. Some nanocarriers are able to interact with the immune system of the vertebrate host, modulating the immune response to the elimination of pathogenic microorganisms. In this overview of nanotechnology-based delivery strategies for established and new antichagasic agents, different strategies, and limitations of a wide class of nanocarriers are explored, as new perspectives in the treatment and monitoring of Chagas disease.

Staphylococcus aureus phagocytosis is affected by senescence

Senescent cells accumulate in multicellular animals with aging, resulting in organ or tissue dysfunction. These alterations increase the incidence of a variety of illnesses, including infectious diseases, and, in certain instances, its severity. In search of a rationale for this phenomenon, we focused on the endophagocytic pathway in senescent cells. We first described the endocytic vesicle populations at different stages of maturation using confocal microscopy. There was an increase in the number of vacuoles per cell, which was partially explained by an increase in cell size. No changes in vesicle maturation or degradation capacities were determined by microscopy or Western blot assays. Also, we studied the internalization of various endophagocytic cargoes in senescent cells and observed only a decrease in the intracellular recovery of bacteria such as Staphylococcus aureus. Afterwards, we studied the intracellular traffic of S. aureus, and observed no differences in the infection between control and senescent cells. In addition we quantified the recovery of bacteria from control and senescent cells infected in the presence of several inhibitors of endophagosomal maturation, and no changes were observed. These results suggest that bacterial internalization is affected in senescent cells. Indeed, we confirmed this hypothesis by determining minor bacterial adherence and internalization by confocal microscopy. Furthermore, it is important to highlight that we found very similar results with cells from aged animals, specifically BMDMs. This alteration in senescent cells enlightens the diminished bacterial clearance and may be a factor that increases the propensity to suffer severe infectious conditions in the elderly.