Epidrugs: alternative chemotherapy targeting Theileria annulata schizont stage parasites.

The growing emergence of resistance to current anti-theilerial agents necessitates the exploration of alternative approaches to drug discovery. This study evaluated the antiparasitic efficacy of 148 compounds derived from an epigenetic inhibitor library against the schizont stage of a Theileria annulata-infected cell line. Initial screening at a concentration of 10 µM identified 27 compounds exhibiting promising anti-theilerial activity. Further investigation, including determination of the 50% inhibitory concentration (IC50) and host cell cytotoxicity assay, highlighted seven highly effective compounds (SAHA, BVT-948, Trichostatin A, Methylstat, Plumbagin, Ryuvidine, and TCE-5003) against T. annulata-infected cells. Analysis of the active compounds revealed their inhibitory action against various human targets, such as HDAC (SAHA and Trichostatin A), SET domain (Ryuvidine), PRMT (BVT-948 and TCE-5003), histone demethylase (Methylstat), and ROS/apoptosis inducer (Plumbagin). We identified gene orthologs of these targets in Theileria and conducted molecular docking studies, demonstrating effective binding of the compounds with their respective targets in the parasite, supported by in vitro data. Additionally, we performed in silico ADME/T predictions, which indicated potential mutagenic and hepatotoxic effects of Plumbagin, Methylstat, and TCE-5003, rendering them unsuitable for drug development. Conversely, SAHA, Trichostatin A, and BVT-948 showed promising characteristics and may represent potential candidates for future development as chemotherapeutic agents against tropical theileriosis. These findings provide valuable insights into the search for novel anti-theilerial drugs and offer a basis for further research in this area.IMPORTANCETheileria annulata is a protozoan parasite responsible for tropical theileriosis, a devastating disease affecting cattle. Traditional chemotherapy has limitations, and the study explores the potential of epidrugs as an alternative treatment approach. Epidrugs are compounds that modify gene expression without altering the underlying DNA sequence, offering a novel way to combat parasitic infections. This research is pivotal as it addresses the urgent need for innovative therapies against T. annulata, contributing to the development of more effective and targeted treatments for infected livestock. Successful implementation of epidrugs could not only enhance the well-being of cattle but also have broader implications for the control of parasitic diseases, showcasing the paper's significance in advancing veterinary science and improving livestock health globally.

Artemisinin derivatives induce oxidative stress leading to DNA damage and caspase-mediated apoptosis in Theileria annulata-transformed cells.

BACKGROUND: Bovine theileriosis caused by the eukaryotic parasite Theileria annulata is an economically important tick-borne disease. If it is not treated promptly, this lymphoproliferative disease has a significant fatality rate. Buparvaquone (BPQ) is the only chemotherapy-based treatment available right now. However, with the emergence of BPQ resistance on the rise and no backup therapy available, it is critical to identify imperative drugs and new targets against Theileria parasites. METHODS: Artemisinin and its derivatives artesunate (ARS), artemether (ARM), or dihydroartemisinin (DHART) are the primary defence line against malaria parasites. This study has analysed artemisinin and its derivatives for their anti-Theilerial activity and mechanism of action. RESULTS: ARS and DHART showed potent activity against the Theileria-infected cells. BPQ in combination with ARS or DHART showed a synergistic effect. The compounds act specifically on the parasitised cells and have minimal cytotoxicity against the uninfected host cells. Treatment with ARS or DHART induces ROS-mediated oxidative DNA damage leading to cell death. Further blocking intracellular ROS by its scavengers antagonised the anti-parasitic activity of the compounds. Increased ROS production induces oxidative stress and DNA damage causing p53 activation followed by caspase-dependent apoptosis in the Theileria-infected cells. CONCLUSIONS: Our findings give unique insights into the previously unknown molecular pathways underpinning the anti-Theilerial action of artemisinin derivatives, which may aid in formulating new therapies against this deadly parasite. Video abstract.

Antitheilerial Activity of the Anticancer Histone Deacetylase Inhibitors.

The apicomplexan parasite, Theileria annulata, is the most prevalent hemoprotozoan in livestock, causing significant economic losses worldwide. It is essential to develop new and improved therapeutics, as current control measures are compromised by the development of resistance against the only available antitheilerial drug, buparvaquone (BPQ). Histone deacetylase inhibitors (HDACi) were shown to treat cancer effectively and revealed in vitro antiparasitic activity against apicomplexan parasites such as Plasmodium and Toxoplasma. In this study, we investigated the antitheilerial activity of the four anti-cancer HDACi (vorinostat, romidepsin, belinostat, and panobinostat) against the schizont stage of T. annulata parasites. All four HDACi showed potent activity and increased hyperacetylation of the histone-4 protein. However, based on the low host cell cytotoxicity and IC50 values, vorinostat (0.103 µM) and belinostat (0.069 µM) were the most effective showing antiparasitic activity. The parasite-specific activities of the HDACi (vorinostat and belinostat) were evaluated by western blotting using parasite-specific antibodies and in silico analysis. Both vorinostat and belinostat reduced the Theileria infected cell viability by downregulating anti-apoptotic proteins and mitochondrial dysfunction, leading to caspase-dependent cell apoptosis. The HDACi caused irreversible and antiproliferative effects on the Theileria infected cell lines. Our results collectively showed that vorinostat and belinostat could be used as an alternative therapy for treating Theileria parasites.