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Frontiers in Cellular and Infection... 2022The spread of artemisinin resistant parasites is of global concern and highlights the need to identify new antimalarials for future treatments. Azithromycin, a...
INTRODUCTION
The spread of artemisinin resistant parasites is of global concern and highlights the need to identify new antimalarials for future treatments. Azithromycin, a macrolide antibiotic used clinically against malaria, kills parasites two mechanisms: 'delayed death' by inhibiting the bacterium-like ribosomes of the apicoplast, and 'quick-killing' that kills rapidly across the entire blood stage development.
METHODS
Here, 22 azithromycin analogues were explored for delayed death and quick-killing activities against (the most virulent human malaria) and (a monkey parasite that frequently infects humans).
RESULTS
Seventeen analogues showed improved quick-killing against both species, with up to 38 to 20-fold higher potency over azithromycin after less than 48 or 28 hours of treatment for and , respectively. Quick-killing analogues maintained activity throughout the blood stage lifecycle, including ring stages of parasites (<12 hrs treatment) and were >5-fold more selective against than human cells. Isopentenyl pyrophosphate supplemented parasites that lacked an apicoplast were equally sensitive to quick-killing analogues, confirming that the quick killing activity of these drugs was not directed at the apicoplast. Further, activity against the related apicoplast containing parasite and the gram-positive bacterium did not show improvement over azithromycin, highlighting the specific improvement in antimalarial quick-killing activity. Metabolomic profiling of parasites subjected to the most potent compound showed a build-up of non-haemoglobin derived peptides that was similar to chloroquine, while also exhibiting accumulation of haemoglobin-derived peptides that was absent for chloroquine treatment.
DISCUSSION
The azithromycin analogues characterised in this study expand the structural diversity over previously reported quick-killing compounds and provide new starting points to develop azithromycin analogues with quick-killing antimalarial activity.
Topics: Animals; Humans; Antimalarials; Azithromycin; Parasites; Plasmodium falciparum; Malaria, Falciparum; Chloroquine; Malaria
PubMed: 36530422
DOI: 10.3389/fcimb.2022.1063407 -
Microbiology Resource Announcements Feb 2023We are reporting the nearly complete genome of Theileria equi (Piroplasmida, Apicomplexa), which contains four nuclear chromosomes, a mitochondrial genome, and an...
We are reporting the nearly complete genome of Theileria equi (Piroplasmida, Apicomplexa), which contains four nuclear chromosomes, a mitochondrial genome, and an apicoplast from the NVSL354 reference isolate. This report includes all six genetic molecules.
PubMed: 36688717
DOI: 10.1128/mra.00809-22 -
Bioscience Reports Jun 2022The untangling or overwinding of genetic material is an inevitable part of DNA replication, repair, recombination, and transcription. Topoisomerases belong to a... (Review)
Review
The untangling or overwinding of genetic material is an inevitable part of DNA replication, repair, recombination, and transcription. Topoisomerases belong to a conserved enzyme family that amends DNA topology during various processes of DNA metabolism. To relax the genetic material, topoisomerases transiently break the phosphodiester bond on one or both DNA strands and remain associated with the cleavage site by forming a covalent enzyme-DNA intermediate. This releases torsional stress and allows the broken DNA to be re-ligated by the enzyme. The biological function of topoisomerases ranges from the separation of sister chromatids following DNA replication to the aiding of chromosome condensation and segregation during mitosis. Topoisomerases are also actively involved in meiotic recombination. The unicellular apicomplexan parasite, Plasmodium falciparum, harbors different topoisomerase subtypes, some of which have substantially different sequences and functions from their human counterparts. This review highlights the biological function of each identified Plasmodium topoisomerase along with a comparative analysis of their orthologs in human or other model organisms. There is also a focus on recent advancements towards the development of topoisomerase chemical inhibitors, underscoring the druggability of unique topoisomerase subunits that are absent in humans. Plasmodium harbors three distinct genomes in the nucleus, apicoplast, and mitochondria, respectively, and undergoes non-canonical cell division during the schizont stage of development. This review emphasizes the specific developmental stages of Plasmodium on which future topoisomerase research should focus.
Topics: Biology; DNA Replication; DNA Topoisomerases, Type I; Humans; Mitosis; Plasmodium
PubMed: 35699968
DOI: 10.1042/BSR20212847 -
Microbiology Resource Announcements Jun 2024We are reporting a genome containing four nuclear chromosomes, a mitochondrial genome, and an apicoplast from reference isolate NVSL348. This report includes a gapless...
We are reporting a genome containing four nuclear chromosomes, a mitochondrial genome, and an apicoplast from reference isolate NVSL348. This report includes a gapless assembly consisting of all six genetic molecules.
PubMed: 38651914
DOI: 10.1128/mra.00039-24 -
Proceedings of the National Academy of... Apr 2023Coenzyme A (CoA) biosynthesis is an excellent target for antimalarial intervention. While most studies have focused on the use of CoA to produce acetyl-CoA in the...
Coenzyme A (CoA) biosynthesis is an excellent target for antimalarial intervention. While most studies have focused on the use of CoA to produce acetyl-CoA in the apicoplast and the cytosol of malaria parasites, mitochondrial acetyl-CoA production is less well understood. In the current study, we performed metabolite-labeling experiments to measure endogenous metabolites in lines with genetic deletions affecting mitochondrial dehydrogenase activity. Our results show that the mitochondrion is required for cellular acetyl-CoA biosynthesis and identify a synthetic lethal relationship between the two main ketoacid dehydrogenase enzymes. The activity of these enzymes is dependent on the lipoate attachment enzyme LipL2, which is essential for parasite survival solely based on its role in supporting acetyl-CoA metabolism. We also find that acetyl-CoA produced in the mitochondrion is essential for the acetylation of histones and other proteins outside of the mitochondrion. Taken together, our results demonstrate that the mitochondrion is required for cellular acetyl-CoA metabolism and protein acetylation essential for parasite survival.
Topics: Plasmodium falciparum; Acetyl Coenzyme A; Acetylation; Mitochondria; Oxidoreductases
PubMed: 37068227
DOI: 10.1073/pnas.2210929120 -
The Journal of Eukaryotic Microbiology Nov 2022Malaria parasites are diheteroxenous, requiring two hosts-a vertebrate and a mosquito-to complete their life cycle. Mosquitoes are the definitive host where malaria... (Review)
Review
Malaria parasites are diheteroxenous, requiring two hosts-a vertebrate and a mosquito-to complete their life cycle. Mosquitoes are the definitive host where malaria parasite sex occurs, and vertebrates are the intermediate host, supporting asexual amplification and more significant geographic spread. In this review, we examine the roles of a single malaria parasite compartment, the relict plastid known as the apicoplast, at each life cycle stage. We focus mainly on two malaria parasite species-Plasmodium falciparum and P. berghei-comparing the changing, yet ever crucial, roles of their apicoplasts.
Topics: Humans; Animals; Apicoplasts; Parasites; Rodentia; Plasmodium falciparum; Life Cycle Stages; Malaria; Protozoan Proteins
PubMed: 36070203
DOI: 10.1111/jeu.12947 -
Infection and Drug Resistance 2020Malaria is among the most devastating and widespread tropical parasitic diseases in which most prevalent in developing countries. Antimalarial drug resistance is the... (Review)
Review
Malaria is among the most devastating and widespread tropical parasitic diseases in which most prevalent in developing countries. Antimalarial drug resistance is the ability of a parasite strain to survive and/or to multiply despite the administration and absorption of medicine given in doses equal to or higher than those usually recommended. Among the factors which facilitate the emergence of resistance to existing antimalarial drugs: the parasite mutation rate, the overall parasite load, the strength of drug selected, the treatment compliance, poor adherence to malaria treatment guideline, improper dosing, poor pharmacokinetic properties, fake drugs lead to inadequate drug exposure on parasites, and poor-quality antimalarial may aid and abet resistance. Malaria vaccines can be categorized into three categories: pre-erythrocytic, blood-stage, and transmission-blocking vaccines. Molecular markers of antimalarial drug resistance are used to screen for the emergence of resistance and assess its spread. It provides information about the parasite genetics associated with resistance, either single nucleotide polymorphisms or gene copy number variations which are associated with decreased susceptibility of parasites to antimalarial drugs. Glucose transporter PfHT1, kinases (Plasmodium kinome), food vacuole, apicoplast, cysteine proteases, and aminopeptidases are the novel targets for the development of new antimalarial drugs. Therefore, this review summarizes the antimalarial drug resistance and novel targets of antimalarial drugs.
PubMed: 33204122
DOI: 10.2147/IDR.S279433 -
ELife Mar 2024The apicoplast is a four-membrane plastid found in the apicomplexans, which harbors biosynthesis and organelle housekeeping activities in the matrix. However, the...
The apicoplast is a four-membrane plastid found in the apicomplexans, which harbors biosynthesis and organelle housekeeping activities in the matrix. However, the mechanism driving the flux of metabolites, in and out, remains unknown. Here, we used TurboID and genome engineering to identify apicoplast transporters in . Among the many novel transporters, we show that one pair of apicomplexan monocarboxylate transporters (AMTs) appears to have evolved from a putative host cell that engulfed a red alga. Protein depletion showed that AMT1 and AMT2 are critical for parasite growth. Metabolite analyses supported the notion that AMT1 and AMT2 are associated with biosynthesis of isoprenoids and fatty acids. However, stronger phenotypic defects were observed for AMT2, including in the inability to establish parasite virulence in mice. This study clarifies, significantly, the mystery of apicoplast transporter composition and reveals the importance of the pair of AMTs in maintaining the apicoplast activity in apicomplexans.
Topics: Animals; Mice; Toxoplasma; Parasites; Apicoplasts; Fatty Acids; Organic Chemicals; Protozoan Proteins
PubMed: 38502570
DOI: 10.7554/eLife.88866 -
PLoS Pathogens Oct 2023Isoprenoid precursor synthesis is an ancient and fundamental function of plastid organelles and a critical metabolic activity of the apicoplast in Plasmodium malaria...
Isoprenoid precursor synthesis is an ancient and fundamental function of plastid organelles and a critical metabolic activity of the apicoplast in Plasmodium malaria parasites [1-3]. Over the past decade, our understanding of apicoplast properties and functions has increased enormously [4], due in large part to our ability to rescue blood-stage parasites from apicoplast-specific dysfunctions by supplementing cultures with isopentenyl pyrophosphate (IPP), a key output of this organelle [5,6]. In this Pearl, we explore the interdependence between isoprenoid metabolism and apicoplast biogenesis in P. falciparum and highlight critical future questions to answer.
Topics: Animals; Apicoplasts; Parasites; Plasmodium falciparum; Malaria, Falciparum; Protozoan Proteins
PubMed: 37883328
DOI: 10.1371/journal.ppat.1011713 -
The EMBO Journal Aug 2021Malaria parasites contain an essential organelle called the apicoplast that houses metabolic pathways for fatty acid, heme, isoprenoid, and iron-sulfur cluster...
Malaria parasites contain an essential organelle called the apicoplast that houses metabolic pathways for fatty acid, heme, isoprenoid, and iron-sulfur cluster synthesis. Surprisingly, malaria parasites can survive without the apicoplast as long as the isoprenoid precursor isopentenyl pyrophosphate (IPP) is supplemented in the growth medium, making it appear that isoprenoid synthesis is the only essential function of the organelle in blood-stage parasites. In the work described here, we localized an enzyme responsible for coenzyme A synthesis, DPCK, to the apicoplast, but we were unable to delete DPCK, even in the presence of IPP. However, once the endogenous DPCK was complemented with the E. coli DPCK (EcDPCK), we were successful in deleting it. We were then able to show that DPCK activity is required for parasite survival through knockdown of the complemented EcDPCK. Additionally, we showed that DPCK enzyme activity remains functional and essential within the vesicles present after apicoplast disruption. These results demonstrate that while the apicoplast of blood-stage P. falciparum parasites can be disrupted, the resulting vesicles remain biochemically active and are capable of fulfilling essential functions.
Topics: Apicoplasts; Pantothenic Acid; Phosphotransferases (Alcohol Group Acceptor); Plasmodium falciparum; Protozoan Proteins
PubMed: 34031901
DOI: 10.15252/embj.2020107247