Hydroxamate-based compounds are potent inhibitors of Toxoplasma gondii HDAC biological activity

An Amazing 30-Year Journey around the DABO Family: A Medicinal Chemistry Lesson on a Versatile Class of Non-nucleoside HIV-1 Reverse Transcriptase Inhibitors

Since the emergence of AIDS, the non-nucleoside HIV-1 RT inhibitors (NNRTIs) have attracted the attention of scientists and clinicians due to their high potency and specificity combined with low toxicity. 3,4-Dihydro-2-alkoxy-6-benzyl-4-oxopyrimidines (DABOs) are a family of NNRTIs described since 1992, and the best members among S-, NH-, and N,N-DABOs showed high anti-HIV-1 potency in both cellular and enzymatic assays. During 30 years of research, the central 4-(3H)-pyrimidinone nucleus has been decorated with 2,6-dihaloaryl or cyclohexyl groups at the methylene at C6, alkyl- or (arylalkyl/aroylalkyl)thio/amino chains at C2, and hydrogen or a small alkyl group at C5. The further introduction of small (i.e., methoxy) groups at the C6 α-benzylic position furnished potency at the sub-nanomolar level against wild-type HIV-1 and at the nanomolar level against HIV-1 mutant strains. Importantly, some compounds of the DABO family exhibited preventative microbicidal activity, valuable in clinical settings where oral adherence rates are low.

N-(9-Acridinyl) Amino Acid Derivatives: Synthesis and In Vitro Evaluation of Anti-Toxoplasma gondii Activity

Background/Objectives: Acridine, an aromatic heterocyclic compound, serves as a basis for the synthesis of potent bioactive derivatives, displaying a broad spectrum of biological activity, such as antibacterial, antitumor, and antiparasitic activity. With the ability to undergo various types of electrophilic substitutions, introducing different side chains could lead to compounds being active towards various and potentially multiple biotargets. Toxoplasma gondii, a ubiquitous protozoan parasite with worldwide distribution, poses a major health threat, particularly in immunocompromised patients and fetuses. Current treatment options for toxoplasmosis are scarce, with notable limitations, especially regarding side myelotoxicity and inactivity towards T. gondii cysts, causing a need for novel drug candidates. The aim of this study was to evaluate selected N-(9-acrydinil) amino acid derivatives as potential anti-T. gondii agents. Methods: Synthesis of new derivatives was performed using a two-step method, with the initial mixing of 9-chloroacridine with methanol and sodium alkoxide solution and subsequent adding of appropriate amino acids. Cytotoxicity of the tested compounds was evaluated on the Vero cell line using a MTT assay, while their anti-T. gondii activity was investigated using T. gondii RH strain tachyzoites. Results: CC50 values of the derivatives ranged from 41.72 to 154.10 µM. Anti-T. gondii activity, displayed as a reduction in the number of viable tachyzoites compared to the untreated control, ranged from 0 to 33.3%. One of the derivatives displayed activity comparable to the standard treatment option while retaining acceptable cytotoxicity. Esterification, presence of aromatic substituents and the length of the amino acid side chain were identified as key factors that affect both toxicity and activity of these derivatives. Conclusions: Promising results obtained throughout this study provide guidelines for further structural modifications of N-(9-acrydinil) amino acid derivatives in order to synthesize drug candidates competitive to standard treatment options for toxoplasmosis.

Characterization of the Activities of Vorinostat Against Toxoplasma gondii

Toxoplasma gondii is a globally widespread pathogen of significant veterinary and medical importance, causing abortion or congenital disease in humans and other warm-blooded animals. Nevertheless, the current treatment options are restricted and sometimes result in toxic side effects. Hence, it is essential to discover drugs that demonstrate potent anti-Toxoplasma activity. Herein, we found that vorinostat, a pan-HDAC inhibitor, exhibited an IC50 value of 260.1 nM against the T. gondii RH strain and a selectivity index (SI) > 800 with respect to HFF cells. Vorinostat disrupted the entire lytic cycle of T. gondii in vitro. Proteome analysis indicated that vorinostat remarkably perturbed the protein expression of T. gondii, and proteins involved in "DNA replication" and "membrane" were significantly dysregulated. Furthermore, we found that vorinostat significantly enhanced ROS production and induced parasite apoptosis. Importantly, vorinostat could prolong survival in a murine model. Our findings reveal that vorinostat is effective against T. gondii both in vitro and in vivo, suggesting its potential as a therapeutic option for human toxoplasmosis.

Rhoptry proteins affect the placental barrier in the context of Toxoplasma gondii infection: Signaling pathways and functions

Toxoplasma gondii is an opportunistic and pathogenic obligate intracellular parasitic protozoan that is widespread worldwide and can infect most warm-blooded animals, seriously endangering human health and affecting livestock production. Toxoplasmosis caused by T. gondii infection has different clinical manifestations, which are mainly determined by the virulence of T. gondii and host differences. Among the manifestations of this condition, abortion, stillbirth, and fetal malformation can occur if a woman is infected with T. gondii in early pregnancy. Here, we discuss how the T. gondii rhoptry protein affects host pregnancy outcomes and speculate on the related signaling pathways involved. The effects of rhoptry proteins of T. gondii on the placental barrier are complex. Rhoptry proteins not only regulate interferon-regulated genes (IRGs) to ensure the survival of parasites in activated cells but also promote the spread of worms in tissues and the invasive ability of the parasites. The functions of these rhoptry proteins and the associated signaling pathways highlight relevant mechanisms by which Toxoplasma crosses the placental barrier and influences fetal development and will guide future studies to uncover the complexity of the host-pathogen interactions.

Proteomics Applications in Toxoplasma gondii: Unveiling the Host-Parasite Interactions and Therapeutic Target Discovery

Toxoplasma gondii, a protozoan parasite with the ability to infect various warm-blooded vertebrates, including humans, is the causative agent of toxoplasmosis. This infection poses significant risks, leading to severe complications in immunocompromised individuals and potentially affecting the fetus through congenital transmission. A comprehensive understanding of the intricate molecular interactions between T. gondii and its host is pivotal for the development of effective therapeutic strategies. This review emphasizes the crucial role of proteomics in T. gondii research, with a specific focus on host-parasite interactions, post-translational modifications (PTMs), PTM crosstalk, and ongoing efforts in drug discovery. Additionally, we provide an overview of recent advancements in proteomics techniques, encompassing interactome sample preparation methods such as BioID (BirA*-mediated proximity-dependent biotin identification), APEX (ascorbate peroxidase-mediated proximity labeling), and Y2H (yeast two hybrid), as well as various proteomics approaches, including single-cell analysis, DIA (data-independent acquisition), targeted, top-down, and plasma proteomics. Furthermore, we discuss bioinformatics and the integration of proteomics with other omics technologies, highlighting its potential in unraveling the intricate mechanisms of T. gondii pathogenesis and identifying novel therapeutic targets.