BjussuLAAO-II, an l-amino acid oxidase from Bothrops jararacussu snake venom, impairs Toxoplasma gondii infection in human trophoblast cells and villous explants from the third trimester of pregnancy

Bothrops snake venom L-amino acid oxidases impair biofilm formation of clinically relevant bacteria

The present work addressed the abilities of two L-amino acid oxidases isolated from Bothrops moojeni (BmooLAAO-I) and Bothrops jararacussu (BjussuLAAO-II) snake venoms to control the growth and prevent the biofilm formation of clinically relevant bacterial pathogens. Upon S. aureus (ATCC BAA44) and S. aureus (clinical isolates), BmooLAAO-I (MIC = 0.12 and 0.24 μg/mL, respectively) and BjussuLAAO-II (MIC = 0.15 μg/mL) showed a potent bacteriostatic effect. Against E. coli (ATCC BAA198) and E. coli (clinical isolates), BmooLAAO-I (MIC = 15.6 and 62.5 μg/mL, respectively) and BjussuLAAO-II (MIC = 4.88 and 9.76 μg/mL, respectively) presented a lower extent effect. Also, BmooLAAO-I (MICB50 = 0.195 μg/mL) and BjussuLAAO-II (MICB50 = 0.39 μg/mL) inhibited the biofilm formation of S. aureus (clinical isolates) in 88% and 89%, respectively, and in 89% and 53% of E. coli (clinical isolates). Moreover, scanning electron microscopy confirmed that the toxins affected bacterial morphology by increasing the roughness of the cell surface and inhibited the biofilm formation. Furthermore, analysis of the tridimensional structures of the toxins showed that the surface-charge distribution presents a remarkable positive region close to the glycosylation motif, which is more pronounced in BmooLAAO-I than BjussuLAAO-II. This region may assist the interaction with bacterial and biofilm surfaces. Collectively, our findings propose that venom-derived antibiofilm agents are promising biotechnological tools which could provide novel strategies for biofilm-associated infections.

Trypanosoma cruzi P21 recombinant protein modulates Toxoplasma gondii infection in different experimental models of the human maternal-fetal interface

Introduction

Toxoplasma gondii is the etiologic agent of toxoplasmosis, a disease that affects about one-third of the human population. Most infected individuals are asymptomatic, but severe cases can occur such as in congenital transmission, which can be aggravated in individuals infected with other pathogens, such as HIV-positive pregnant women. However, it is unknown whether infection by other pathogens, such as Trypanosoma cruzi, the etiologic agent of Chagas disease, as well as one of its proteins, P21, could aggravate T. gondii infection.

Methods

In this sense, we aimed to investigate the impact of T. cruzi and recombinant P21 (rP21) on T. gondii infection in BeWo cells and human placental explants.

Results

Our results showed that T. cruzi infection, as well as rP21, increases invasion and decreases intracellular proliferation of T. gondii in BeWo cells. The increase in invasion promoted by rP21 is dependent on its binding to CXCR4 and the actin cytoskeleton polymerization, while the decrease in proliferation is due to an arrest in the S/M phase in the parasite cell cycle, as well as interleukin (IL)-6 upregulation and IL-8 downmodulation. On the other hand, in human placental villi, rP21 can either increase or decrease T. gondii proliferation, whereas T. cruzi infection increases T. gondii proliferation. This increase can be explained by the induction of an anti-inflammatory environment through an increase in IL-4 and a decrease in IL-6, IL-8, macrophage migration inhibitory factor (MIF), and tumor necrosis factor (TNF)-α production.

Discussion

In conclusion, in situations of coinfection, the presence of T. cruzi may favor the congenital transmission of T. gondii, highlighting the importance of neonatal screening for both diseases, as well as the importance of studies with P21 as a future therapeutic target for the treatment of Chagas disease, since it can also favor T. gondii infection.

Rottlerin impairs early and late steps of Toxoplasma gondii infection in human trophoblast cells and villous explants

Congenital toxoplasmosis, caused by the opportunistic protozoan parasite T. gondii, can cause stillbirths, miscarriages and fetal abnormalities, as well as encephalitis and chorioretinitis in newborns. Available treatment options rely on antiparasitic drugs that have been linked to serious side effects, high toxicity and the development of drug-resistant parasites. The search for alternative therapeutics to treat this disease without acute toxicity for the mother and child is essential for the advancement of current therapeutic procedures. The present study aimed to unravel the mode of the anti-T. gondii action of Rottlerin, a natural polyphenol with multiple pharmacological properties described. Herein, we further assessed the antiparasitic activity of Rottlerin against T. gondii infection on the human trophoblastic cells (BeWo cells) and, for the first time, on human villous explants. We found that non-cytotoxic doses of Rottlerin impaired early and late steps of parasite infection with an irreversible manner in BeWo cells. Rottlerin caused parasite cell cycle arrest in G1 phase and compromised the ability of tachyzoites to infect new cells, thus highlighting the possible direct action on parasites. An additional and non-exclusive mechanism of action of Rottlerin involves the modulation of host cell components, by affecting lipid droplet formation, mitochondrial function and upregulation of the IL-6 and MIF levels in BeWo cells. Supporting our findings, Rottlerin also controlled T. gondii proliferation in villous explants with low toxicity and reduced the IL-10 levels, a cytokine associated with parasite susceptibility. Collectively, our results highlighted the potential use of Rottlerin as a promising tool to prevent and/or treat congenital toxoplasmosis.