bims-toxgon 2025-06-15 papers

bims-toxgon

Biomed News

on Toxoplasma gondii metabolism

Issue of 2025–06–15
twenty-one papers selected by
Lakesh Kumar, BITS Pilani

Toxoplasma gondii parasites induce a localized myeloid cell immune response surrounding parasites in the brain during acute infection.
PTPA Governs Stress-Responsive Differentiation and Metabolic Homeostasis in Toxoplasma gondii.
Toxoplasma IMC1 is a central component of the subpellicular network and plays critical roles in parasite morphology, replication, and infectivity.
Anti-Toxoplasma gondii efficacy of beta, beta-dimethylacrylshikonin and isobutyrylshikonin in vitro and in vivo.
Bug as a drug: Unveiling anti-cancer properties of Toxoplasma gondii and its therapeutic prospects in cancer immunotherapy.
Sexually aggressive behavior triggered by parasitic infection - how parasites can influence our personality.
Dynamics of amylopectin granule accumulation during the course of chronic Toxoplasma infection is linked to intra-cyst bradyzoite replication.
Lipid profiling of Toxoplasma tachyzoites and the mouse host.
Perillyl Alcohol Exerts an Anti-Toxoplasma gondii Effect by Regulating the Expression of Genes Related To Isoprenylation.
GNAT family Pat2 lysine acetylation of glycerol kinase and its key role in glycerol metabolism in hypersaline-adapted archaea.
A dynamic barrier: remodeling of the nuclear envelope during closed mitosis in malaria parasites.
Nutrient acquisition by intracellular parasitic protists.
First epidemiological survey of Toxoplasma gondii in Galapagos sea lions (Zalophus wollebaeki).
Stage-specific MCM protein expression in Trypanosoma cruzi: insights into metacyclogenesis and G1 arrested epimastigotes.
Biochemical and structural characterization of a GNAT superfamily protein acetyltransferase from Helicobacter pylori.
Berberine dissociates mitochondrial complex I by SIRT3-dependent deacetylation of NDUFS1 to improve hepatocellular glucose and lipid metabolism.
Artificial intelligencemethods for protein folding and design.
OGDHL regulates nucleotide metabolism, tumor growth, and neuroendocrine marker expression in prostate cancer.
PFKFB2 is Pivotal for Metabolic Flexibility and Differential Glucose Utilization.
Research progress on cancer-related epigenetic switches.
SETD5-Coordinated LC3B Methylation Inhibits Autophagy in Ovarian Cancer.

mBio. 2025 Jun 10. e0081025

Toxoplasma gondii parasites induce a localized myeloid cell immune response surrounding parasites in the brain during acute infection.

Stephanie B Orchanian, Sebastian Zolog, Julia Tomasello, Rijul Malik, Ji-Hun Shin, Anita Koshy, Melissa B Lodoen.

  Toxoplasma gondii is a foodborne intracellular parasite that chronically infects the brain. Although T. gondii infection elicits a protective immune response, the nature of the monocyte response in the immediate vicinity of parasites during initial brain infection is not well understood. By infecting mice with T. gondii and comparing areas of the brain containing or not containing parasites, we found an increase in CCR2+ monocytes, IBA1+ myeloid cells, GFAP+ astrocytes, and CD68+ signal near parasites in the brain, indicating immune cell infiltration and phagolysosomal activation in response to the infection. CCR2+CD68+ monocytes were specifically increased near tachyzoites with minimal localization of these cells near cysts in the brain. This monocyte response was also detected near parasite-interacted cells, identified using T. gondii parasites that inject Cre recombinase into "interacted" cells of Ai6 CCR2RFP/+ mice, enabling us to track these events in vivo. The chemokine CCL2 and its transcription factor NF-κB were also upregulated surrounding parasites in the brain; however, the T. gondii effector protein GRA15, which sustains NF-κB activation in infected cells, was not required for CCL2 production, NF-κB activation, or myeloid cell recruitment to parasites in the brain. In contrast, active T. gondii replication played a more significant role, as CCR2+ monocytes were recruited to replication-competent but not replication-deficient T. gondii delivered via intracranial injection into mice. These findings provide novel insights into the drivers of immune cell mobilization and activation in the brain during initial T. gondii central nervous system infection and highlight the importance of parasite replication in this process.
IMPORTANCE: Toxoplasma gondii is a brain-infecting parasite, and the mobilization of peripheral immune cells to the brain is critical for controlling T. gondii infection. However, the initial events driving these cells to sites of T. gondii infection in the brain are poorly understood. We show that peripheral myeloid immune cell recruitment and activation are specific to areas of the brain containing actively replicating parasites, which are capable of lysing host cells. This local immune response is characterized by focal chemokine production, myeloid cell recruitment, and the activation of phagolysosomal pathways. These highly localized host responses were independent of the parasite effector protein that induces NF-κB activation within infected cells, GRA15. However, the localized monocyte recruitment was dependent on live parasites and active parasite replication. This research highlights the importance of host cell sensing of parasite replication in the brain for immune control of T. gondii infection.

Keywords:  Toxoplasma gondii; brain; immune response; monocyte; myeloid cells; neuroinflammation

DOI:  https://doi.org/10.1128/mbio.00810-25
Cells. 2025 Jun 03. pii: 835. [Epub ahead of print]14(11):

PTPA Governs Stress-Responsive Differentiation and Metabolic Homeostasis in Toxoplasma gondii.

Zhu Ying, Yuntong Wu, Yanqun Pei, Zheng Shang, Jing Liu, Qun Liu.

  The protozoan parasite Toxoplasma gondii transitions between acute (tachyzoite) and chronic (bradyzoite) stages, enabling lifelong persistence in hosts. Iron depletion triggers bradyzoite differentiation, with the phosphotyrosyl phosphatase activator (PTPA) identified as a key regulator. Here, we define PTPA's role in T. gondii pathogenesis. PTPA forms a ternary complex with PP2A A/C subunits, validated by reciprocal pull-down assays. Depleting PTPA impaired tachyzoite proliferation, invasion, and gliding motility, while stress-induced bradyzoites exhibited defective cyst formation and vacuolar swelling. Metabolic dysregulation included amylopectin accumulation and lipid droplet proliferation. The PP2A inhibitor LB-100 phenocopied PTPA depletion, suppressing tachyzoite growth and bradyzoite differentiation. TgPTPA emerges as a linchpin coordinating PP2A activity, metabolic flux, and lifecycle transitions. Its dual roles in acute virulence and chronic persistence, combined with LB-100's efficacy, position the PTPA-PP2A axis as a promising target for antitoxoplasmosis strategies.

Keywords:  LB-100; Toxoplasma gondii; amylopectin metabolism; bradyzoite differentiation; phosphotyrosyl phosphatase activator

DOI:  https://doi.org/10.3390/cells14110835
bioRxiv. 2025 Jun 04. pii: 2025.06.03.657516. [Epub ahead of print]

Toxoplasma IMC1 is a central component of the subpellicular network and plays critical roles in parasite morphology, replication, and infectivity.

Juliette N Uy, Qing Lou, Z Hong Zhou, Peter J Bradley.

Toxoplasma gondii and related apicomplexan parasites utilize a unique membrane and cytoskeletal organelle called the inner membrane complex (IMC) for maintaining cell shape, motility, host cell invasion, and replication. The cytoskeleton portion of the organelle is a network of filaments composed of proteins called alveolins, whose precise functions and organization are poorly understood. Here we describe the function of the founding member of the Toxoplasma alveolins, IMC1, which we show is expressed and loaded onto forming daughter buds with IMC4, but later than the other key alveolins IMC3, IMC6, and IMC10. Disruption of IMC1 results in severe morphological defects that impact the integrity of the parasite's cytoskeleton and disrupt invasion, replication, and egress. Loss of IMC1 in a less virulent type II strain results in a dramatic loss of infectivity and complete failure to form a chronic infection. We then use deletion analyses to dissect functional regions of the protein which reveals a key subregion of the alveolin domain that is sufficient for IMC targeting and also required for function. We then show that IMC1 interacts directly with IMC4 and the loss of IMC1 results in mislocalization of IMC4 specifically in forming daughter buds. This study thus reveals the critical role that IMC1 plays in forming and maintaining the architecture of the filamentous network of the IMC.
Significance: Parasites in the phylum Apicomplexa maintain their intracellular lifestyle using specialized organelles that mediate the lytic cycle of host cell invasion, intracellular replication, and egress. One of these organelles is the inner membrane complex (IMC), which consists of membrane vesicles supported by a cytoskeletal meshwork formed from proteins called alveolins. This study focuses on the first identified alveolin IMC1 and determines its precise function via expression timing, gene knockout, deletion and mutagenesis, partner identification, and in vivo infection studies. We show that this protein is critical to the ultrastructure of the parasite which is important for every stage of its lytic cycle. We also identify key regions of the protein that are important for localization, function, and interaction with another key alveolin, IMC4.

DOI: https://doi.org/10.1101/2025.06.03.657516
Parasit Vectors. 2025 Jun 09. 18(1): 217

Anti-Toxoplasma gondii efficacy of beta, beta-dimethylacrylshikonin and isobutyrylshikonin in vitro and in vivo.

Hai-Ting Guo, Lu Wang, Bintao Zhai, Shi-Chen Xie, Wen-Bin Zheng, Xing-Quan Zhu, Zhong-Yuan Li.

   BACKGROUND: Toxoplasma gondii is a widespread parasite that can infect almost all vertebrate species including humans, causing variable clinical symptoms from asymptomatic infection to serious diseases. Though extensive research has been done in recent decades, the prevention and control of T. gondii continue to present substantial challenges. Herbal medicines have long been a rich source of chemical entities and may provide new avenues for drug discovery against T. gondii. Thus, this study was performed to investigate the anti-T. gondii effect of two monomers, beta, beta-dimethylacrylshikonin (DMAS) and isobutyrylshikonin (IBS), extracted from the roots of a widely distributed and used medical plant.
METHODS: The cytotoxicity of DMAS and IBS on Vero cells was evaluated using the MTT assay, and the toxicity in mice was assessed on the basis of the changes of body weight combined with the histopathologic examinations on spleen, liver, and kidney. The effects of DMAS and IBS on mice against T. gondii acute infection were evaluated by combining survival curves with splenic histopathologic examination. Ultrastructural change in T. gondii tachyzoites post co-incubation in vitro was observed by electron microscopy. ACT1-quantitative polymerase chain reaction (qPCR) was conducted to quantify T. gondii tachyzoites, including proliferation and the inhibitory efficacy of DMAS and IBS. Invasion and attachment, intracellular proliferation, and parasitophorous vacuole viability evaluations were conducted to assess the effects on the asexual life cycle of T. gondii. In addition, untargeted metabolomics analysis was performed to clarify the underlying mechanisms by which DMAS and IBS act against this parasite.
RESULTS: Both DMAS and IBS, with higher half-maximal cytotoxic concentration (CC50) values, exhibited concentration-dependent cytotoxicity in Vero cells and significantly inhibited the intracellular proliferation of T. gondii in vitro, showing lower half-maximal inhibitory concentration (IC50) values and higher selectivity index (SI) values. DMAS showed a statistically more potent effect than IBS, but both were not significantly more potent than that of pyrimethamine (PM). The tachyzoites exhibited severe ultrastructural damage following treatment with DMAS or IBS. Metabolomics analysis indicated that this abnormal biological lesion was caused by the disruptions in purine and pyrimidine metabolism pathways in T. gondii, with mechanisms likely differing from that of PM. In vivo, a dose of 1.5 mg/kg of DMAS showed no significant toxicity in Kunming (KM) mice, with no significant pathological damage or weight loss. At this dosage, both DMAS and IBS significantly alleviated the splenic hyperemia and statistically prolonged the survival times of T. gondii-infected mice.
CONCLUSIONS: This study demonstrated that DMAS and IBS have an inhibitory effect on T. gondii infection in vitro and in vivo, probably associated with the disruption of nucleotide metabolism in the parasite. These results highlight that the two monomers, in particular DMAS, hold promise as a potential therapeutic medicine for toxoplasmosis.

Keywords:   Toxoplasma gondii ; Anti-infection; Beta, beta-dimethylacrylshikonin; Isobutyrylshikonin; Metabolomics

DOI:  https://doi.org/10.1186/s13071-025-06865-1
Acta Trop. 2025 Jun 09. pii: S0001-706X(25)00160-3. [Epub ahead of print]267 107684

Bug as a drug: Unveiling anti-cancer properties of Toxoplasma gondii and its therapeutic prospects in cancer immunotherapy.

Yie Wei Chua, Sek Chuen Chow.

  In light of the growing global cancer burden, the development of novel therapeutic strategies is urgently needed. Recently, pathogens have been examined for their potential in immunotherapy, with Toxoplasma gondii (T. gondii) emerging as an unexpected yet promising candidate. Given the widespread prevalence of T. gondii, particularly in tropical regions where climatic conditions favor the oocyst transmission, understanding its therapeutic potential may have far-reaching implications for global health. This review explores the potential of T. gondii as a cancer immunotherapy by examining various T. gondii variants characterized in current studies. It highlights the multifaceted mechanisms behind T. gondii's anti-cancer properties, including the induction of Th1 immune responses, immunostimulation of the tumor microenvironment, inhibition of angiogenesis, invasion and metastasis, as well as the induction of cancer cell apoptosis. However, several challenges hinder the application of T. gondii in immunotherapy, such as safety concerns related to viable T. gondii, its limited efficacy against non-solid tumors, and the need for further validation of non-viable T. gondii components. Additionally, the role of humoral immunity and potential synergies with conventional therapies require further investigation. Addressing these challenges could significantly enhance the efficacy and safety of T. gondii-based immunotherapy, offering a novel approach to cancer treatment and potentially improving patient outcomes.

Keywords:  Cancer immunotherapy; Host immunity; Parasite-based immunotherapy; Toxoplasma gondii; Tumor microenvironment (TME)

DOI:  https://doi.org/10.1016/j.actatropica.2025.107684
Front Psychiatry. 2025 ;16 1555024

Sexually aggressive behavior triggered by parasitic infection - how parasites can influence our personality.

Marco Goczol.

  Parasitic infections are not only a health problem, but also a psychological and behavioral one. Research shows that certain parasites can influence the personality traits and behavior of infected individuals. Toxoplasma gondii, a well-known parasite, is suspected of increasing the risk of sexually aggressive behavior. This paper examines the links between parasitic infections and personality changes and analyzes the mechanisms by which parasites can affect the nervous system and associated behaviors. The aim is to raise awareness of the psychological and behavioral effects of parasitic infections and to stimulate future research in this area.

Keywords:  Toxoplasma gondii; neuropsychiatric; parasitic infection; personality change; psychological behavior; sexual aggression

DOI:  https://doi.org/10.3389/fpsyt.2025.1555024
mSphere. 2025 Jun 10. e0020525

Dynamics of amylopectin granule accumulation during the course of chronic Toxoplasma infection is linked to intra-cyst bradyzoite replication.

Aashutosh Tripathi, Ryan W Donkin, Joy S Miracle, Robert D Murphy, Matthew S Gentry, Abhijit Patwardhan, Anthony P Sinai.

  The contribution of amylopectin granules (AG), a branched chain storage homopolymer of glucose, to the maintenance and progression of the chronic Toxoplasma gondii infection has remained undefined. Here, we describe the role of AG in the physiology of encysted bradyzoites using a purpose-developed imaging-based application, AmyloQuant, which permitted the quantification of relative levels of AG within in vivo-derived tissue cysts during the initiation and maturation of chronic infection. Our findings establish that AG are dynamic, exhibiting considerable heterogeneity among tissue cysts at all post-infection time points examined. Quantification of relative steady-state AG levels within tissue cysts reveals a previously unrecognized temporal cycle involving both phases of AG accumulation and utilization over the first 6 weeks of the chronic infection. This AG cycle is temporally coordinated with overall bradyzoite mitochondrial activity. In addition, the staging of AG levels is defined by a period of low accumulation, leading into a phase of high accumulation, followed by apparent rapid utilization associated with a coordinated burst of intra-cyst bradyzoite replication. These findings suggest that AG may represent a key component in the licensing of bradyzoite replication, intimately linking stored metabolic potential to the course of the chronic infection, thereby extending the impact of AG beyond the previously assigned role in transmission. These findings force a fundamental reassessment of the chronic Toxoplasma infection, highlighting the critical need to address the temporal progression of this crucial stage in the parasite life cycle.IMPORTANCEAmylopectin granules (AG) represent a storage polymer of glucose within Toxoplasma gondii bradyzoites, the life cycle stage associated with the chronic infection. In this study, we report on the development of AmyloQuant, an image-based application, to investigate the levels and distribution of AG within encysted bradyzoites in the murine brain with the progression of the chronic infection. Quantification reveals that AG, although heterogeneous both within and across tissue cysts, exhibit a previously unrecognized temporal cycle that is linked to the overall mitochondrial activity and the capacity to replicate in vivo. This confirms that encysted bradyzoites, long considered dormant, retain considerable metabolic activity, with AG playing a potentially critical role in defining and perhaps licensing the progression of this life-long persistent infection.

Keywords:  Toxoplasma gondii; amylopectin; bradyzoite; chronic infection; mitochondrial metabolism; restriction checkpoint

DOI:  https://doi.org/10.1128/msphere.00205-25
Vet Parasitol. 2025 Jun 06. pii: S0304-4017(25)00137-2. [Epub ahead of print]338 110526

Lipid profiling of Toxoplasma tachyzoites and the mouse host.

Lijun Shi, Lin Liang, Wenchao Li, Cun Liu, Kun Han, Xinghui Zhao, Zhanzhong Zhao.

  Our understanding of lipids in Toxoplasma gondii and its host is incomplete. This study aimed to analyze phospholipids and sphingolipids in tachyzoites and mice. RH strain tachyzoites were cultured and purified. Models using BALB/c and C57BL/6 mice injected intraperitoneally (i.p.) with tachyzoites or carbon tetrachloride (CCl4) were developed and evaluated. Samples were analyzed with liquid chromatography-electrospray ionization tandem mass spectrometry (LC-MS-MS) method. In tachyzoites, phospholipids [phosphatidic acid (PA), phosphatidylcholine (PC), oxidized PC, phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylinositol (PI), and phosphatidylserine (PS)], lysophospholipids (LPLs)[lysophosphatidic acid (LPA), lysophosphatidylcholine (LPC), lysophosphatidylglycerol (LPG), lysophosphatidylinositol (LPI), and lysophosphatidylserine (LysoPS)], fatty acids (FAs) and their metabolites [arachidonic acid (20:4 AA), docosahexaenoic acid (22:6 DHA), prostaglandins, epoxyeicosatrienoic acid (EET), and dihydroxyeicosatrienoic acid (DHET)], were detected, suggesting de novo synthesis, PC oxidation, phospholipase action, and metabolism of FAs. Sphingolipids [ceramide (Cer) and sphingomyelin (SM)] were also detected in the tachyzoites. In mice, the histopathological changes in the tissues and plasma, are thought to be associated with changes in phospholipids and sphingolipids at the local and circulating levels. These changes create a parasitized microenvironment for Toxoplasma gondii. Current evidence suggests that 16:0 20:4 PC, 16:0 22:6 PC, 18:0 22:6 PE, 16:0 22:6 PI, 22:6 DHA, d18:1 23:0 SM, 16:0 Cer and 16:0 cerebroside (16:0 Cb) are important as potential biomarkers and targets of Toxoplasma gondii infection. Overall, the comprehensive and comparative profiling of lipids in tachyzoites and the mouse host has been achieved, contributing to the understanding of Toxoplasma lipid biology and the exploration of strategies against toxoplasmosis.

Keywords:  Acute infection; Mouse; Phospholipid; Sphingolipid; Tachyzoite; Toxoplasma gondii

DOI:  https://doi.org/10.1016/j.vetpar.2025.110526
Acta Parasitol. 2025 Jun 11. 70(3): 130

Perillyl Alcohol Exerts an Anti-Toxoplasma gondii Effect by Regulating the Expression of Genes Related To Isoprenylation.

Yihao Yu, Qingyang Song, Hongmei Li, Shujing Wang, Xiaomin Zhao, Ningning Zhao, Xiao Zhang.

   PURPOSE: Recent years have seen increased focused on developing new anti-parasitic drugs that are both highly effective and low in toxicity, as the widespread use of existing anti-parasitic drugs has raised growing concerns. Natural products have gained significant interest due to their diverse biological activities with minimal toxic side effects. Our previous studies have already demonstrated the good anti-E. tenella effect of Perillyl Alcohol. To further investigate its efficacy against other protozoa, we selected Toxoplasma gondii as the researchsubject.
METHODS: In this study, we utilized the CCK-8 assay in vitro to assess the cytotoxicity of Perillyl Alcohol on DF-1 cells. The impact of Perillyl Alcohol of T. gondii tachyzoite invasion and intracellular proliferation were investigated in vitro. In vivo, we evaluated the effect of Perillyl Alcohol on the pathogenicity of T. gondii, including host survival time, liver and spleen tissue damage, cysts formed in the brain. Furthermore, we analyzed the expression levels of isoprenylation-related genes using quantitative PCR (qPCR).
RESULTS: The half maximal inhibitory concentration (CC50) of Perillyl Alcohol against DF-1 cells was determined to be 525.0. In vitro studies showed that treatment with Perillyl Alcohol effectively inhibited the invasion rate and intracellular proliferation of T. gondii tachyzoite. The half maximal inhibitory concentration (IC50) was calculated to be 314.3, and further analysis yielded a selectivity index (SI) of 1.67. In vivo, Perillyl Alcohol treatment prolonged the survival time and increased the survival rate of T. gondii-infected mice, while reducing the parasite burden in liver and spleen tissues. It also demonstrated a certain protective effect against T. gondii-induced tissue damage, including effectively alleviating hepatosplenomegaly and mitigating the elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels induced by hepatic injury. Building on this foundation, we further explored the impact of Perillyl Alcohol on the formation of brain cysts and found that it could significantly reduce the number of brain cysts induced by the Pru strain of T. gondii infection. After treatment with Perillyl Alcohol, the expression levels of isoprenylation-related enzymes Tgmecs, Tgdxr, and Tghdr were significantly reduced.
CONCLUSIONS: These results demonstrate that Perillyl Alcohol may suppress the growth of T. gondii by significantly inhibiting the expression of enzymes involved in isoprenoid biosynthesis.

Keywords:   T. Gondii ; Anti-T. Gondii activity; Perillyl alcohol

DOI:  https://doi.org/10.1007/s11686-025-01063-6
bioRxiv. 2025 May 28. pii: 2025.05.27.656527. [Epub ahead of print]

GNAT family Pat2 lysine acetylation of glycerol kinase and its key role in glycerol metabolism in hypersaline-adapted archaea.

Heather N Judd, Karol M Sanchez, Leah S Dublino, Gabriel J Zhang, Daniel Gal, Ricardo L Couto-Rodríguez, Julie A Maupin-Furlow.

Lysine acetylation is a widespread post-translational modification (PTM) involved in regulating key biological processes including central metabolism and chromatin dynamics, yet its roles in archaea remain poorly understood. Here, we investigated two GNAT (Gcn5-related N-acetyltransferase) family homologs, pat1 and pat2 , in the halophilic archaeon Haloferax volcanii (Hv). We found that a pat2 mutant exhibited impaired growth and premature cell death on glycerol, a phenotype not observed in the parent strain, pat1 mutant, or during growth on glucose. Complementation with plasmid-expressed pat2 restored growth on glycerol, confirming this biological role. In vitro assays demonstrated that HvPat2 catalyzes the lysine acetylation of HvGlpK, a glycerol kinase essential for glycerol metabolism. Computational modeling predicted that HvPat2 residues E105, Y154, V110, and N147 may form hydrogen bonds with acetyl-CoA. To assess the functional importance of these residues, alanine substitutions were introduced at each site. Growth assays revealed that E105A and Y154A variants failed to restore growth on glycerol, while V110A and N147A had no significant effect. In vitro , HvPat2 Y154A, E105A, and V110A lacked acetyltransferase activity toward GlpK, whereas N147A retained partial activity. HvPat2 Y154A co-purified with a protein partner, potentially explaining the discrepancy between in vivo and in vitro results. These findings highlight the critical role of the GNAT HvPat2 in mediating lysine acetylation in regulating glycerol metabolism in archaea and offer mechanistic insight into GNAT family acetyltransferases.
IMPORTANCE: GNAT family homologs are widespread and diverse in their use of acyl-CoAs to acylate small molecules and proteins. These functions can be difficult to predict based on in silico analysis alone. Here we reveal a critical role for lysine acetylation in archaeal central carbon metabolism, identifying the GNAT family homolog Pat2 as an essential regulator of glycerol utilization in Haloferax volcanii . The findings expand our understanding of GNAT family acetyltransferases and highlight conserved mechanisms of metabolic control by PTM across domains of life.

DOI: https://doi.org/10.1101/2025.05.27.656527
mSphere. 2025 Jun 09. e0099924

A dynamic barrier: remodeling of the nuclear envelope during closed mitosis in malaria parasites.

Sabrina Absalon.

  Plasmodium falciparum, the protozoan parasite responsible for the most severe form of human malaria, replicates through an unconventional mode of closed mitosis, where the nuclear envelope (NE) remains intact across multiple asynchronous nuclear divisions. This Full Circle minireview illustrates how a decade-long journey-from early electron microscopy observations of nuclear pore dynamics-has evolved into a broader investigation of NE composition, architecture, and regulation across the parasite life cycle. Advances in imaging, including ultrastructure expansion microscopy and cryo-electron tomography, revealed key features such as the bipartite microtubule organizing center, nuclear pore complex rosettes, and specialized NE scaffolds. Structure-guided and proteomic approaches identified divergent SUN-domain proteins, PfSUN1 and PfSUN2, as essential for NE integrity, genome stability, and chromatin positioning during schizogony. Hi-C analyses further uncovered species- and stage-specific chromatin organization, linking peripheral heterochromatin clustering to virulence gene regulation and life cycle progression. Despite lacking lamins, Plasmodium's NE functions as a dynamic architectural hub that bridges chromatin, spindle microtubules, and organelle inheritance. Open questions remain about the full NE proteome, organelle-NE contact sites, and the possibility that mechanical deformation of the nucleus during red blood cell invasion could influence gene expression. These insights not only redefine Plasmodium cell biology but also position NE-associated components as attractive therapeutic targets. By coupling methodological innovation with conceptual inquiry, the study of NE dynamics in Plasmodium offers a powerful model for uncovering general principles of nuclear organization and adaptation in divergent eukaryotes.

Keywords:  Plasmodium falciparum; apicomplexan parasites; closed mitosis; nuclear envelope dynamics; nuclear pore complex; ultrastructure expansion microscopy

DOI:  https://doi.org/10.1128/msphere.00999-24
Cell Host Microbe. 2025 Jun 11. pii: S1931-3128(25)00199-4. [Epub ahead of print]33(6): 854-868

Nutrient acquisition by intracellular parasitic protists.

Giel G van Dooren, Malcolm J McConville.

Parasitic protists belonging to the Apicomplexa and Trypanosomatidae are the cause of important diseases and life-long chronic infections in humans. Several of these parasites replicate within intracellular niches in their mammalian host, including specialized vacuoles, as well as endo-lysosomal compartments or the cytosol of infected cells. These parasites are highly dependent on nutrient salvage pathways in order to satisfy their complex nutrient requirements as well as to maintain different growth and metabolic states. In this review, we provide an overview of common as well as species-specific strategies used by different intracellular parasites to acquire nutrients from their host, emphasizing the link between nutrient salvage and different growth strategies used by these parasites.

DOI: https://doi.org/10.1016/j.chom.2025.05.016
Parasite. 2025 ;32 36

First epidemiological survey of Toxoplasma gondii in Galapagos sea lions (Zalophus wollebaeki).

Juan D Mosquera, Eduardo Diaz, Rosa de Los Ángeles Bayas, Diego Páez-Rosas, Colón Jaime Grijalva-Rosero, Sonia Zapata, Sandie Escotte-Binet, Quentin Di Brasi, Isabelle Villena, Marie-Lazarine Poulle.

  Toxoplasma gondii is the protozoan parasite responsible for toxoplasmosis, a zoonosis that represents a health risk for mammals, including marine species. Felines are the only definitive hosts of this parasite, playing a critical role in the introduction and maintenance of the pathogen in a new environment. Recent data demonstrate the contamination by T. gondii of the terrestrial and seawater environment of the Galapagos archipelago, in the Pacific Ocean. Little is known about the exposure of Galapagos' threatened species to T. gondii, although introduced domestic cats in the archipelago are known to be seropositive for T. gondii. We documented for the first time exposure to T. gondii of Galapagos sea lions (Zalophus wollebaeki), an endemic and emblematic species of the archipelago. The modified agglutination test revealed the presence of antibodies against T. gondii in 61 of 77 plasma samples collected in 2016-2017 from 2- to 4-year-old wild sea lions live-handled in their breeding sites on the inhabited island of San Cristóbal. Antibodies were also detected in 4 of 19 serum samples (21%) from sea lions whose corpses were found in 2021 on the same island. In addition, T. gondii DNA was detected in a lung sample from one necropsied pup and a tissue cyst-like structure was found in another, suggesting infection. These results, together with the high prevalence of antibodies in 2 to 4-year-olds, indicate that Galapagos sea lions are frequently exposed to T. gondii and raise concerns that toxoplasmosis may pose a threat to this endemic species.

Keywords:  Environmental contamination; Marine mammals; Toxoplasmosis; Zoonotic diseases

DOI:  https://doi.org/10.1051/parasite/2025028
Front Cell Infect Microbiol. 2025 ;15 1584812

Stage-specific MCM protein expression in Trypanosoma cruzi: insights into metacyclogenesis and G1 arrested epimastigotes.

Bruno Alves Santarossa, Évelin Mariani, Artur da Paixão Corrêa, Fernanda C Costa, Martin C Taylor, John M Kelly, Maria Carolina Elias, Simone Guedes Calderano.

  Trypanosoma cruzi is a protozoan parasite that is the etiological agent of Chagas disease, which is endemic to Latin America with reported cases in non-endemic regions such as Europe, Asia, and Oceania due to migration. During its lifecycle, T. cruzi alternates between replicative and non-replicative infective lifeforms. Metacyclogenesis is the most studied transition of the T. cruzi life cycle, where replicative epimastigotes differentiate into infective metacyclic trypomastigotes inside the gut of the triatomine vector. This early-branching organism expresses a divergent pre-replication complex (pre-RC) where the only conserved component is the MCM2-7 protein family. Given the role of pre-RC components in cell cycle regulation, we investigated whether MCM expression and location could be involved in proliferation control in epimastigotes and during metacyclogenesis. Using CRISPR/Cas9, we tagged MCM subunits and tracked their expression and subcellular localization. Our findings reveal that MCM subunits are consistently expressed and localized to the nucleus throughout the epimastigote cell cycle, including in G1/G0-arrested cells. However, MCM subunits are degraded during metacyclogenesis as cells enter the G0 state, marking the transition to replication arrest. Therefore, epimastigotes arrested in G1/G0 can either maintain MCM complex expression and resume the cell cycle when conditions become favorable, or they can undergo metacyclogenesis, exiting the cell cycle and entering a G0 state, where MCM subunits are degraded as part of the replication repression mechanism.

Keywords:  G0; G1 arrest; MCM; Mini-Chromosome Maintenance; Trypanosoma cruzi; cell cycle arrest; metacyclogenesis; replication control

DOI:  https://doi.org/10.3389/fcimb.2025.1584812
J Biol Chem. 2025 Jun 10. pii: S0021-9258(25)02206-9. [Epub ahead of print] 110356

Biochemical and structural characterization of a GNAT superfamily protein acetyltransferase from Helicobacter pylori.

Venkatareddy Dadireddy, Amrendra Kumar, Sumith Kumar, Siddhartha P Sarma, Pranjal Mahanta, Suryanarayanarao Ramakumar, Rao N Desirazu.

Helicobacter pylori (H. pylori), a gastric pathogen with high genetic variability and a unique niche, causes peptic ulcers and gastric cancer. Natural transformation contributes to the genetic variability of H. pylori. To date, protein acetylation and the associated acetyltransferase(s) have not been reported in this bacterium. Here, we report protein acetylation in H. pylori and identify a putative protein acetyltransferase, HP0935, capable of acetylating amino acids and proteins including DNA processing protein A (DprA), which is involved in natural transformation. HP0935 acetylates residue K127 in DprA, important for DNA binding, thus likely to regulate natural transformation. We determined the crystal structures of HP0935 in its apo form and in complex with acetyl-coenzyme A (ACO) to 2.00 Å and 2.40 Å resolution, respectively. Structural analysis revealed a conformational change in substrate-binding loops, α1- α2 and β6-β7, upon ACO binding. Structural comparison showed that HP0935 differs from other protein acetyltransferases in the length and orientation of these loops. Molecular dynamics simulation data suggest that these loops are highly dynamic, and ACO binding could affect their dynamics. Given that several proteins may undergo acetylation in H. pylori and the fact that HP0935 is the only known protein acetyltransferase, the loop dynamics are likely to facilitate the acceptance of multiple substrates by HP0935. Structure-based mutational analysis showed that no general base is required for the enzymatic activity. However, a conserved catalytic water molecule at the active site is likely to serve the purpose. Furthermore, the general acid Y127 is essential for enzymatic activity.

DOI: https://doi.org/10.1016/j.jbc.2025.110356
Sci China Life Sci. 2025 Jun 06.

Berberine dissociates mitochondrial complex I by SIRT3-dependent deacetylation of NDUFS1 to improve hepatocellular glucose and lipid metabolism.

Xuekai Wang, Hu Li, Jianrui Li, Lei Lei, Jingchen Xu, Han Sun, Jiayu Li, Jing Jiang, Hongying Li, Mei Tang, Biao Dong, Yue Gong, Jiandong Jiang, Zonggen Peng.

  Many metabolic diseases show mitochondrial abnormalities because of dysfunction of complex I (CI). Therefore, the discovery of drugs that target the CI is of great interest. Berberine (BBR) is a botanic agent and has been included in the latest ESC/EAS Guidelines for the management of dyslipidemias. Here, we showed that BBR enters hepatocyte mitochondria after oral administration and improves glucose and lipid metabolism by reducing oxidative phosphorylation in hepatocytes. BBR inhibits CI function rapidly, selectively, and reversibly, not by directly inhibiting CI enzyme activity but by reducing the abundance of CI in the mitochondria through dissociation of CI. BBR directly binds to and activates Sirtuin 3 (SIRT3), thereby reducing acetylation of the catalytic subunit NDUFS1 in the N-module of CI, leading to dissociation of mitochondrial CI. Conclusively, BBR, as a mitochondria-homing agent, selectively and reversibly dissociates mitochondrial CI through SIRT3-dependent NDUFS1 deacetylation to improve hepatocellular glucose and lipid metabolism, highlighting that CI may be a promising target for innovative natural products to treat metabolic diseases.

Keywords:  GLUCOSE and lipid metabolism; NDUFS1; Sirtuin 3; berberine; mitochondrial complex I

DOI:  https://doi.org/10.1007/s11427-024-2834-8
Curr Opin Struct Biol. 2025 Jun 11. pii: S0959-440X(25)00084-3. [Epub ahead of print]93 103066

Artificial intelligencemethods for protein folding and design.

Zhidian Zhang, Chenxi Ou, Yehlin Cho, Yo Akiyama, Sergey Ovchinnikov.

Machine learning has revolutionized protein structure prediction and design. This review discusses current methods for protein folding and inverse folding challenges. Models like AlphaFold2 (AF2), RoseTTAFold, and ESMFold excel at leveraging evolutionary information to accurately predict protein structures while still struggling to capture the physics of protein folding. Their repurposing for protein design has led to innovations such as RFdiffusion, AF2-design, and relaxed sequence optimization. ProteinMPNN and ESM-IF design sequences based on structure, so they are frequently referred to as "inverse folding' methods. By examining the potential and limitations of current protein design methods and metrics, we provide perspectives on developing models that fully characterize energy landscapes associated with amino acid sequences. Such advances would enable more accurate structure prediction and the design of proteins with specified conformational dynamics, potentially transforming our ability to engineer novel proteins for biotechnological applications.

DOI: https://doi.org/10.1016/j.sbi.2025.103066
bioRxiv. 2025 Jun 01. pii: 2025.05.28.656673. [Epub ahead of print]

OGDHL regulates nucleotide metabolism, tumor growth, and neuroendocrine marker expression in prostate cancer.

Matthew J Bernard, Angel Ruiz, Johnny A Diaz, Nicholas M Nunley, Rachel N Dove, Kylie Y Heering, Sachi Bopardikar, Andrea Gallardo, Takao Hashimoto, Raag Agrawal, Chad M Smith, Blake R Wilde, Nedas Matulionis, Helen M Richards, Marina N Sharifi, Joshua M Lang, Shuang G Zhao, Michael C Haffner, Paul C Boutros, Heather R Christofk, Andrew S Goldstein.

Cells regularly adapt their metabolism in response to changes in their microenvironment or biosynthetic needs. Prostate cancer cells leverage this metabolic plasticity to evade therapies targeting the androgen receptor (AR) signaling pathway. For example, nucleotide metabolism plays a critical role in treatment-resistant prostate cancer by supporting DNA replication, DNA damage response and cell fate decisions. Identifying novel regulators of nucleotide metabolism in treatment-resistant cancer that are dispensable for the health of normal cells may lead to new therapeutic approaches less toxic than commonly used chemotherapies targeting nucleotide metabolism. We identify the metabolic enzyme Oxoglutarate Dehydrogenase-Like (OGDHL), named for its structural similarity to the tricarboxylic acid (TCA) cycle enzyme Oxoglutarate Dehydrogenase (OGDH), as a regulator of nucleotide metabolism, tumor growth, and treatment-induced plasticity in prostate cancer. While OGDHL is a tumor-suppressor in various cancers, we find that its loss impairs prostate cancer cell proliferation and tumor formation while having minimal impact on TCA cycle activity. Loss of OGDHL profoundly decreases nucleotide metabolite pools, induces the DNA damage response marker Ɣ2AX, and alters androgen receptor inhibition-induced plasticity, including suppressing the neuroendocrine markers DLL3 and HES6. Finally, OGDHL is highly expressed in neuroendocrine prostate cancer (NEPC). These findings support an unexpected role of OGDHL in prostate cancer, where it functions to sustain nucleotide pools for proliferation, DNA repair, and AR inhibition-induced plasticity.

DOI: https://doi.org/10.1101/2025.05.28.656673
bioRxiv. 2025 May 27. pii: 2025.05.26.656235. [Epub ahead of print]

PFKFB2 is Pivotal for Metabolic Flexibility and Differential Glucose Utilization.

Kylene M Harold, Satoshi Matsuzaki, Atul Pranay, Jie Zhu, Anna Faakye, Kenneth M Humphries.

Background: The heart's constant energy demands make metabolic flexibility critical to its function as nutrient availability varies. The enzyme phosphofructokinase-2/fructose 2,6-bisphosphatase (PFKFB2) contributes to this flexibility by acting as a positive or negative regulator of cardiac glycolysis. We have previously shown that PFKFB2 is degraded in the diabetic heart and that a cardiac-specific PFKFB2 knockout (cKO) impacts ancillary glucose pathways and mitochondrial substrate preference. Therefore, defining PFKFB2's role in mitochondrial metabolic flexibility is paramount to understanding both metabolic homeostasis and metabolic syndromes. Further, it is unknown how PFKFB2 loss impacts the heart's response to acute stress. Here we examined how cardiac mitochondrial flexibility and the post-translational modification O-GlcNAcylation are affected in cKO mice in response to fasting or pharmacologic stimulation.
Methods: cKO and litter-matched controls (CON) were sacrificed in the fed or fasted (12 hours) states, with or without a 20 minute stimulant stress of caffeine and epinephrine.Mitochondrial respiration, metabolomics, and changes to systemic glucose homeostasis were evaluated.
Results: cKO mice had moderate impairment in mitochondrial metabolic flexibility, affecting downstream glucose oxidation, respiration, and CPT1 activity. O-GlcNAcylation, a product of ancillary glucose metabolism, was upregulated in cKO hearts in the fed state, but this was ameliorated in the fasted state. Furthermore, metabolic remodeling in response to PFKFB2 loss was sufficient to impact circulating glucose in fasted and stressed states.
Conclusions: PFKFB2 is essential for fed-to-fasted changes in cardiac metabolism and plays an important regulatory role in protein O-GlcNAcylation. Its loss also affects systemic glucose homeostasis under stressed conditions.
Graphic Abstract:
Research Perspective: This study raises and answers three key questions: how PFKFB2 contributes to cardiac mitochondrial metabolic flexibility, how post-prandial status regulates O-GlcNAcylation in a PFKFB2-dependent manner, and how altered cardiac glucose use impacts systemic glucose homeostasis under stress.These findings highlight a novel role for nutrient state in regulating cardiac metabolism, and especially O-GlcNAcylation, with PFKFB2 loss.Future studies should investigate whether reducing O-GlcNAcylation through fasting is sufficient to ameliorate pathological changes observed in the absence of PFKFB2.

DOI: https://doi.org/10.1101/2025.05.26.656235
Invest New Drugs. 2025 Jun 13.

Research progress on cancer-related epigenetic switches.

Chunyu Yu, Jie Sun, Jinlong Tong, Ziqing Xu, Qijia Zhang.

  The dysregulation of cellular epigenetic machinery has been established as a fundamental driver of oncogenesis. This recognition has propelled cancer epigenetics to the forefront of biomedical research, particularly regarding the mechanistic characterization of epigenetic switching events. These molecular switches represent critical regulatory nodes in the malignant transformation. The epigenetic switch is a complex structure formed through interactions between nucleic acid-protein complexes or protein-protein interaction complexes and specific DNA fragments. Triggered by a priming event, this molecular apparatus can reversibly activate or repress the transcription of multiple downstream genes. The inherent reversibility of these epigenetic switches presents novel therapeutic opportunities for targeted cancer intervention. Consequently, this review provides a systematic analysis of cancer-associated epigenetic switches identified in the past decade.

Keywords:  Cancer; Epigenetic switch; Epigenetics; Target

DOI:  https://doi.org/10.1007/s10637-025-01555-2
FASEB J. 2025 Jun 15. 39(11): e70700

SETD5-Coordinated LC3B Methylation Inhibits Autophagy in Ovarian Cancer.

Yanan Hou, Mingyang Li, Ziwei Zhang, Bowen Zhang, Ting Huang, Yifan Yang, Aiqin Sun, Qiong Lin, Genbao Shao.

  MAP1LC3/LC3 is an essential autophagy regulator involved in both the formation of autophagosome and the recruitment of autophagy cargo. Although several post-translational modifications (PTMs) have been identified to regulate the function of LC3, the effect of protein methylation on its function has not been well characterized. Here, we show that SETD5 interacts with and methylates nuclear LC3B (a member of the LC3 subfamily) at lysines 5 and 65, leading to its nuclear retention. In the nucleus of human ovarian cancer (OC) cells, methylated LC3B binds the nuclear transcription factor PRDM10 to the promoter regions of autophagy-related genes (ATGs), including ATG2a, ATG7, ATG12, and ATG16L1, to suppress their transcription, thereby resulting in reduced formation of autophagosomes. Moreover, the methylation of LC3B facilitates OC cell migration by inhibiting autophagy. Overall, our study defines a novel modification of LC3B and unveils a SETD5-mediated methylation-dependent regulatory mechanism controlling nuclear LC3B function in autophagy and migration in OC cells, offering potential therapeutic targets for OC.

Keywords:  LC3B; SET domain containing 5; autophagy; ovarian cancer; posttranslational modification

DOI:  https://doi.org/10.1096/fj.202402487R