bims-toxgon 2022-08-14 papers

bims-toxgon

Biomed News

on Toxoplasma gondii metabolism

Issue of 2022–08–14
eleven papers selected by
Lakesh Kumar, BITS Pilani

Proteomic characterization of the Toxoplasma gondii cytokinesis machinery portrays an expanded hierarchy of its assembly and function.
Lactate is an epigenetic metabolite that drives survival in model systems of glioblastoma.
Development of an Immunochromatographic Test Based on Rhoptry Protein 14 for Serological Detection of Toxoplasma gondii Infection in Swine.
The role of AMPK-Sirt1-autophagy pathway in the intestinal protection process by propofol against regional ischemia/reperfusion injury in rats.
mTORC1 controls Golgi architecture and vesicle secretion by phosphorylation of SCYL1.
The association between Toxoplasma infection and mortality: the NHANES epidemiologic follow-up study.
Acetyl-CoA Deficiency Is Involved in the Regulation of Iron Overload on Lipid Metabolism in Apolipoprotein E Knockout Mice.
Hernandezine, a natural herbal alkaloid, ameliorates type 2 diabetes by activating AMPK in two mouse models.
A comparative study of microRNAs in different stages of Eimeria tenella.
A nuclear redox sensor modulates gene activation and var switching in Plasmodium falciparum.
Association between Toxoplasma gondii Infection and Nephrotic Syndrome Risk in Children: A Case-Control Study and Systematic Review.

Nat Commun. 2022 Aug 08. 13(1): 4644

Proteomic characterization of the Toxoplasma gondii cytokinesis machinery portrays an expanded hierarchy of its assembly and function.

Klemens Engelberg, Tyler Bechtel, Cynthia Michaud, Eranthie Weerapana, Marc-Jan Gubbels.

The basal complex (BC) is essential for T. gondii cell division but mechanistic details are lacking. Here we report a reciprocal proximity based biotinylation approach to map the BC's proteome. We interrogate the resulting map for spatiotemporal dynamics and function by disrupting the expression of components. This highlights four architecturally distinct BC subcomplexes, the compositions of which change dynamically in correlation with changes in BC function. We identify BCC0 as a protein undergirding BC formation in five foci that precede the same symmetry seen in the apical annuli and IMC sutures. Notably, daughter budding from BCC0 progresses bidirectionally: the apical cap in apical and the rest of the IMC in basal direction. Furthermore, the essential role of the BC in cell division is contained in BCC4 and MORN1 that form a 'rubber band' to sequester the basal end of the assembling daughter cytoskeleton. Finally, we assign BCC1 to the non-essential, final BC constriction step.

DOI: https://doi.org/10.1038/s41467-022-32151-0
Mol Cell. 2022 Aug 09. pii: S1097-2765(22)00647-5. [Epub ahead of print]

Lactate is an epigenetic metabolite that drives survival in model systems of glioblastoma.

Consuelo Torrini, Trang Thi Thu Nguyen, Chang Shu, Angeliki Mela, Nelson Humala, Aayushi Mahajan, Erin Heather Seeley, Guoan Zhang, Mike-Andrew Westhoff, Georg Karpel-Massler, Jeffrey N Bruce, Peter Canoll, Markus D Siegelin.

  Lactate accumulates to a significant amount in glioblastomas (GBMs), the most common primary malignant brain tumor with an unfavorable prognosis. However, it remains unclear whether lactate is metabolized by GBMs. Here, we demonstrated that lactate rescued patient-derived xenograft (PDX) GBM cells from nutrient-deprivation-mediated cell death. Transcriptome analysis, ATAC-seq, and ChIP-seq showed that lactate entertained a signature of oxidative energy metabolism. LC/MS analysis demonstrated that U-13C-lactate elicited substantial labeling of TCA-cycle metabolites, acetyl-CoA, and histone protein acetyl-residues in GBM cells. Lactate enhanced chromatin accessibility and histone acetylation in a manner dependent on oxidative energy metabolism and the ATP-citrate lyase (ACLY). Utilizing orthotopic PDX models of GBM, a combined tracer experiment unraveled that lactate carbons were substantially labeling the TCA-cycle metabolites. Finally, pharmacological blockage of oxidative energy metabolism extended overall survival in two orthotopic PDX models in mice. These results establish lactate metabolism as a novel druggable pathway for GBM.

Keywords:  ATAC-seq; ChIP-seq; glioblastoma; lactate; metabolic flux analysis; tumor metabolism

DOI:  https://doi.org/10.1016/j.molcel.2022.06.030
Animals (Basel). 2022 Jul 28. pii: 1929. [Epub ahead of print]12(15):

Development of an Immunochromatographic Test Based on Rhoptry Protein 14 for Serological Detection of Toxoplasma gondii Infection in Swine.

Yimin Yang, Yechuan Huang, Xianfeng Zhao, Mi Lin, Lulu Chen, Mingxiu Zhao, Xueqiu Chen, Yi Yang, Guangxu Ma, Chaoqun Yao, Siyang Huang, Aifang Du.

  Toxoplasma gondii, a worldwide distributed apicomplexan protozoan, can infect almost all warm-blooded animals and may cause toxoplasmosis. In order to provide a point-of-care detection method for T. gondii infection, an immunochromatographic test (ICT) was established. The proposed test uses recombinant T. gondii rhoptry protein 14 (ROP14) conjugated with 20 nm gold particles, recombinant protein A as the detection line and monoclonal antibody TgROP14-5D5 as the control line. The specificity, sensitivity, positive predictive value, negative predictive value and stability of this new ICT were evaluated. rTgROP14 was specifically recognized by positive serum of T. gondii but not negative serum. mAb TgROP14-5D5 showed higher specific recognition of T. gondii antigens and was therefore selected for subsequent colloidal gold strip construction. The new ICT based on TgROP14 exhibited good diagnostic performance with high specificity (86.9%) and sensitivity (90.9%) using IHA as a "reference standard". Among 436 field porcine sera, ICT and IHA detected 134 (30.7%) and 99 (22.7%) positive samples, respectively. The relative agreement was 87.8%. These data indicate that this new ICT based on TgROP14 is a suitable candidate for routine testing of T. gondii in the field.

Keywords:  TgROP14; Toxoplasma gondii; immunochromatographic test; swine

DOI:  https://doi.org/10.3390/ani12151929
Int Immunopharmacol. 2022 Aug 04. pii: S1567-5769(22)00598-7. [Epub ahead of print]111 109114

The role of AMPK-Sirt1-autophagy pathway in the intestinal protection process by propofol against regional ischemia/reperfusion injury in rats.

Xiao Liu, Bo Yang, Ya-Fang Tan, Jian-Guo Feng, Jing Jia, Cheng-Jie Yang, Ye Chen, Mao-Hua Wang, Jun Zhou.

  Intestinal ischemia/reperfusion (II/R) is a clinical event associated with high morbidity and mortality. AMP-activated protein kinase (AMPK), a central cellular energy sensor, is associated with oxidative stress and inflammation. However, whether the AMPK is involved in the II/R-induced intestinal injury and the underlying mechanism is yet to be elucidated. Propofol has a protective effect on organs; yet, its specific mechanism of action remains unclear. This study explored the role of the AMPK-Sirt1-autophagy pathway in intestinal injury, and whether propofol could reduce intestinal injury and investigated the mechanisms in a rat model of II/R injury as well as a cell model (IEC-6 cells) of hypoxia/reoxygenation (H/R). Propofol, AMPK agonist (AICAR) and AMPK inhibitor (Compound C) were then administered, respectively. The histopathological changes, cell viability and apoptosis were detected. Furthermore, the levels of proinflammatory factors, the activities of oxidative stress, diamine oxidase, and signaling pathway were also analyzed. The results demonstrated that the AMPK-Sirt1-autophagy pathway of intestine was activated after II/R or H/R. Propofol could further activate the pathway, which reduced intestinal injury, inhibited apoptosis, reversed inflammation and oxidative stress, and improved the 24-hour survival rate in II/R rats in vivo, and attenuated H/R-induced IEC-6 cell injury, oxidative stress, and apoptosis in vitro, as fine as changes in AICAR treatment. Compound C abrogated the protective effect of propofol on II/R and H/R-induced injury. These results suggested a crucial effect of AMPK on the mechanism of intestinal injury and might provide a new insight into the mechanism of propofol reducing II/R injury.

Keywords:  AMPK; Autophagy; Intestinal injury; Propofol; Sirt1

DOI:  https://doi.org/10.1016/j.intimp.2022.109114
Nat Commun. 2022 Aug 10. 13(1): 4685

mTORC1 controls Golgi architecture and vesicle secretion by phosphorylation of SCYL1.

Stéphanie Kaeser-Pebernard, Christine Vionnet, Muriel Mari, Devanarayanan Siva Sankar, Zehan Hu, Carole Roubaty, Esther Martínez-Martínez, Huiyuan Zhao, Miguel Spuch-Calvar, Alke Petri-Fink, Gregor Rainer, Florian Steinberg, Fulvio Reggiori, Jörn Dengjel.

The protein kinase mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of cell growth and proliferation, supporting anabolic reactions and inhibiting catabolic pathways like autophagy. Its hyperactivation is a frequent event in cancer promoting tumor cell proliferation. Several intracellular membrane-associated mTORC1 pools have been identified, linking its function to distinct subcellular localizations. Here, we characterize the N-terminal kinase-like protein SCYL1 as a Golgi-localized target through which mTORC1 controls organelle distribution and extracellular vesicle secretion in breast cancer cells. Under growth conditions, SCYL1 is phosphorylated by mTORC1 on Ser754, supporting Golgi localization. Upon mTORC1 inhibition, Ser754 dephosphorylation leads to SCYL1 displacement to endosomes. Peripheral, dephosphorylated SCYL1 causes Golgi enlargement, redistribution of early and late endosomes and increased extracellular vesicle release. Thus, the mTORC1-controlled phosphorylation status of SCYL1 is an important determinant regulating subcellular distribution and function of endolysosomal compartments. It may also explain the pathophysiology underlying human genetic diseases such as CALFAN syndrome, which is caused by loss-of-function of SCYL1.

DOI: https://doi.org/10.1038/s41467-022-32487-7
Parasit Vectors. 2022 Aug 06. 15(1): 284

The association between Toxoplasma infection and mortality: the NHANES epidemiologic follow-up study.

Jiaofeng Huang, Jiaolong Zheng, Bang Liu, Lingling Lu, Haicong Wu, Su Lin, Dongliang Li.

   BACKGROUND: Toxoplasma gondii has been reported to be associated with higher mortality in patients with schizophrenia. This study aimed to explore the relationship between T. gondii infection and 25-year mortality based on data from the Third National Health and Nutrition Examination Survey (NHANES III) database.
METHODS: Cases with serum T. gondii antibody test results were included in this study and the corresponding mortality dataset was obtained from the US National Center for Health Statistics (NCHS). Propensity score matching (PSM) was used to match age and sex between groups. The Cox proportional hazards model was used to evaluate the effect of T. gondii infection on mortality.
RESULTS: A total of 14,181 cases were included in the analysis, of which 3831 (27.0%) were seropositive for T. gondii antibody. The median follow-up time of the whole cohort was 22.5 (interquartile range 16.3, 24.5) years. A total of 5082 deaths were observed in this cohort, a mortality rate of 35.8%. All-cause mortality was significantly higher in the seropositive group than in the seronegative group (50.0% vs 30.6%, P < 0.001). Kaplan-Meier analysis showed a significant difference in the survival time between two groups before and after PSM. Multivariate analysis showed that T. gondii infection was independently associated with higher all-cause mortality after adjusting for potential confounders.
CONCLUSIONS: Toxoplasma gondii infection is associated with higher mortality in general population.

Keywords:  Mortality; NHANES; Toxoplasma gondii; Toxoplasmosis

DOI:  https://doi.org/10.1186/s13071-022-05398-1
Molecules. 2022 Aug 04. pii: 4966. [Epub ahead of print]27(15):

Acetyl-CoA Deficiency Is Involved in the Regulation of Iron Overload on Lipid Metabolism in Apolipoprotein E Knockout Mice.

Gang Luo, Lu Xiang, Lin Xiao.

  The role of dietary iron supplementation in the development of nonalcoholic fatty liver disease (NAFLD) remains controversial. This study aimed to investigate the effect of excess dietary iron on NAFLD development and the underlying mechanism. Apolipoprotein E knockout mice were fed a chow diet, a high-fat diet (HFD), or an HFD containing 2% carbonyl iron (HFD + Fe) for 16 weeks. The serum and liver samples were acquired for biochemical and histopathological examinations. Isobaric tags for relative and absolute quantitation were performed to identify differentially expressed proteins in different groups. Excess dietary iron alleviated HFD-induced NAFLD, as evidenced by significant decreases in serum/the hepatic accumulation of lipids and the NAFLD scores in HFD + Fe-fed mice compared with those in HFD-fed mice. The hepatic acetyl-CoA level was markedly decreased in the HFD + Fe group compared with that in the HFD group. Important enzymes involved in the source and destination of acetyl-CoA were differentially expressed between the HFD and HFD + Fe groups, including the enzymes associated with cholesterol metabolism, glycolysis, and the tricarboxylic acid cycle. Furthermore, iron overload-induced mitochondrial dysfunction and oxidative stress occurred in mouse liver, as evidenced by decreases in the mitochondrial membrane potential and antioxidant expression. Therefore, iron overload regulates lipid metabolism by leading to an acetyl-CoA shortage that reduces cholesterol biosynthesis and might play a role in NAFLD pathogenesis. Iron overload-induced oxidative stress and mitochondrial dysfunction may impair acetyl-CoA formation from pyruvate and β-oxidation. Our study provides acetyl-CoA as a novel perspective for investigating the pathogenesis of NAFLD.

Keywords:  acetyl-CoA; cholesterol; iron overload; non-alcoholic fatty liver disease; oxidative stress; proteomics

DOI:  https://doi.org/10.3390/molecules27154966
Phytomedicine. 2022 Jul 28. pii: S0944-7113(22)00445-7. [Epub ahead of print]105 154366

Hernandezine, a natural herbal alkaloid, ameliorates type 2 diabetes by activating AMPK in two mouse models.

Jing Bai, Shuai Zhang, Jinjing Cao, Hongbin Sun, Zhiguo Mang, Wei L Shen, Hao Li.

   BACKGROUND: AMP-activated protein kinase (AMPK) is an effective target for treating diabetes. However, successful drug development is delayed due to issues including toxicity. Plant-derived natural product AMPK activators have emerged as a new way to treat diabetes due to its potential low safety risks. Here, we studied the effect of hernandezine (HER), a natural product derived from Thalictrum, in activating AMPK and treating T2D in mouse models.
METHOD: We tested HER in various cells and tissues, including primary hepatocytes, skeletal myotubes cell lines, as well as major metabolic tissues from diabetic (db/db) and diet-induced obesity (DIO) model mice. The effect of HER on glucose uptake via AMPK in vitro and in vivo was confirmed utilizing cell transfection and adenovirus interference analysis. Tissue staining assessed the effect of HER on adipogenesis. Real-time quantitative polymerase chain reaction (real-time PCR) was applied to verify the effect of HER on transcription factors. Western blot analysis was used to determine the activation of phosphorylated AMPK and ACC pathways.
RESULTS: Biochemically, we found that HER prevented pAMPK from dephosphorylation to prolong its activity, disproving previous direct activation model and providing a new model to explain HER-mediated AMPK activation. HER could be orally delivered to animals and has a 3-fold long half-life in vivo as compared to metformin. Importantly, long-term oral HER treatment potently reduced body weight and blood glucose in both type 2 diabetes mullitus (T2DM) mouse models by increasing glucose disposal and reducing lipogenesis, and appeared not to induce cardiac hypertrophy.
CONCLUSION: Natural product HER indirectly activates AMPK by suppressing its dephosphorylation. Oral HER effectively alleviated hyperglycemia and reduced body weight in T2D mouse models, appeared to have a low risk of causing cardiac hypertrophy, and might be a potential therapeutic option for T2DM.

Keywords:  AMPK; Diabetes mellitus; Glucose disposal; Hernandezine; Lipogenesis

DOI:  https://doi.org/10.1016/j.phymed.2022.154366
Front Vet Sci. 2022 ;9 954725

A comparative study of microRNAs in different stages of Eimeria tenella.

Lei Zhang, Linlin Chen, Hongtao Zhang, Hongbin Si, Xianyong Liu, Xun Suo, Dandan Hu.

  Apicomplexan parasites have divergent biogenesis machinery for small RNA generation. Analysis has shown that parasites in Plasmodium and Cryptosporidium as well as many species in Leishmania or Trypanosoma do not have a complete machinery in small RNA biogenesis. Recently, the miRNA-generating system of Toxoplasma has been identified as plant/fungal-like and its miRNAome has been elucidated. However, the microRNA (miRNA) expression profiles and their potential regulatory functions in different stages of Eimeria tenella remain largely unknown. In this study, we characterized the RNA silencing machinery of E. tenella and investigated the miRNA population distribution at different life stages by high-throughput sequencing. We characterized the expression of miRNAs in the unsporulated oocyst, sporulated oocyst and schizogony stages, obtaining a total of 392 miRNAs. We identified 58 differentially expressed miRNAs between USO (unsporulated oocysts) and SO (sporulated oocysts) that were significantly enriched for their potential target genes in the regulation of gene expression and chromatin binding, suggesting an epigenetic modulation of sporulating by these miRNAs. In comparing miRNA expression at endogenous and exogenous developmental stages, twenty-four miRNAs were identified differently expressed. Those were mainly associated with the regulation of genes with protein kinase activity, suggesting control of protein phosphorylation. This is the first study about the evolution of miRNA biogenesis system and miRNA control of gene expression in Eimeria species. Our data may lead to functional insights into of the regulation of gene expression during parasite life cycle in apicomplexan parasites.

Keywords:  Argonaute; Eimeria tenella; dicer; gene expression; miRNA

DOI:  https://doi.org/10.3389/fvets.2022.954725
Proc Natl Acad Sci U S A. 2022 Aug 16. 119(33): e2201247119

A nuclear redox sensor modulates gene activation and var switching in Plasmodium falciparum.

Adina Heinberg, Inbar Amit-Avraham, Vera Mitesser, Karina Simantov, Manish Goyal, Yuval Nevo, Sofia Kandelis-Shalev, Emilie Thompson, Ron Dzikowski.

  The virulence of Plasmodium falciparum, which causes the deadliest form of human malaria, is attributed to its ability to evade the human immune response. These parasites "choose" to express a single variant from a repertoire of surface antigens called PfEMP1, which are placed on the surface of the infected red cell. Immune evasion is achieved by switches in expression between var genes, each encoding a different PfEMP1 variant. While the mechanisms that regulate mutually exclusive expression of var genes are still elusive, antisense long-noncoding RNAs (lncRNAs) transcribed from the intron of the active var gene were implicated in the "choice" of the single active var gene. Here, we show that this lncRNA colocalizes with the site of var mRNA transcription and is anchored to the var locus via DNA:RNA interactions. We define the var lncRNA interactome and identify a redox sensor, P. falciparum thioredoxin peroxidase I (PfTPx-1), as one of the proteins associated with the var antisense lncRNA. We show that PfTPx-1 localizes to a nuclear subcompartment associated with active transcription on the nuclear periphery, in ring-stage parasite, when var transcription occurs. In addition, PfTPx-1 colocalizes with S-adenosylmethionine synthetase (PfSAMS) in the nucleus, and its overexpression leads to activation of var2csa, similar to overexpression of PfSAMS. Furthermore, we show that PfTPx-1 knockdown alters the var switch rate as well as activation of additional gene subsets. Taken together, our data indicate that nuclear PfTPx-1 plays a role in gene activation possibly by providing a redox-controlled nuclear microenvironment ideal for active transcription.

Keywords:  Plasmodium falciparum; lncRNA; malaria; thioredoxin peroxidase; var genes

DOI:  https://doi.org/10.1073/pnas.2201247119
J Trop Pediatr. 2022 Aug 04. pii: fmac067. [Epub ahead of print]68(5):

Association between Toxoplasma gondii Infection and Nephrotic Syndrome Risk in Children: A Case-Control Study and Systematic Review.

Hadi Sorkhi, Abolfazl Mollalo, Ali Bijani, Saeed Mehravar, Mohammad Pournasrollah, Sahar Sadr Moharerpour, Ali Rostami.

  Some evidence suggests toxoplasmosis as an etiology of nephrotic syndrome (NS) in children; however, no observational study evaluated this relationship. In a case-control study, we enrolled 35 children with NS and 37 healthy children. All participants were examined for anti-Toxoplasma immunoglobulin G and M (IgG and IgM) antibodies using enzyme-linked immunosorbent assay. We also systematically reviewed the literature to assess this relationship. Prevalence of anti-Toxoplasma IgG was 17.4% and 13.5% in cases and controls, respectively, indicating a non-significant association (adjusted odds ratio, 1.22, 95% confidence interval, 0.35-4.41). No subjects were seropositive for IgM. In a systematic review, we found that acute toxoplasmosis can induce NS in some children and anti-Toxoplasma treatment is effective in the remission of NS in these cases. In pediatrics with NS, acute toxoplasmosis should be considered as a neglected causative factor.

Keywords:   Toxoplasma gondii ; children; nephrotic syndrome

DOI:  https://doi.org/10.1093/tropej/fmac067