ABSTRACT
BACKGROUND: This is a follow-up study to the pentaerythrityl tetranitrate randomized controlled multicenter trial that reports neonatal outcome data of newborns admitted to neonatal intensive care units and outcome data of the offspring at 12 months of age. OBJECTIVE: We present data on adverse events reported during the study to document the safety of pentaerythrityl tetranitrate treatment during pregnancy. To further evaluate the effects of pentaerythrityl tetranitrate on neonatal and long-term outcomes, we present follow up data from of 240 children at 12 months of age, including information on height, weight, head circumference, developmental milestones, and the presence of chronic disease and of 144 newborns admitted to the neonatal intensive care unit during the trial. STUDY DESIGN: The pentaerythrityl tetranitrate trial was a randomized, double-blind, placebo-controlled study designed to assess the efficacy and safety of the nitric oxide-donor pentaerythrityl tetranitrate in the prevention of fetal growth restriction and perinatal death in pregnancies complicated by abnormal placental perfusion. RESULTS: Results at 12 months demonstrated that significantly more children were age appropriately developed without impairments in the pentaerythrityl tetranitrate group (P=.018). In addition, the presence of chronic disease was lower in the pentaerythrityl tetranitrate group (P=.041). Outcome data of the 144 newborns admitted to the neonatal intensive care unit did not reveal differences between the treatment and placebo groups. There were no differences in the number or nature of reported adverse events between the study groups. CONCLUSION: The analysis shows that study children born in the pentaerythrityl tetranitrate cohort have a clear advantage compared with the placebo group at the age of 12 months, as evidenced by the increased incidence of normal development without the presence of chronic disease. Although safety has been proven, further follow-up studies are necessary to justify pentaerythrityl tetranitrate treatment during pregnancies complicated by impaired uterine perfusion.
Subject(s)
Fetal Growth Retardation , Pentaerythritol Tetranitrate , Humans , Female , Pregnancy , Double-Blind Method , Follow-Up Studies , Infant, Newborn , Pentaerythritol Tetranitrate/administration & dosage , Pentaerythritol Tetranitrate/adverse effects , Pentaerythritol Tetranitrate/pharmacology , Infant , Fetal Growth Retardation/epidemiology , Male , Perinatal Death/prevention & control , Intensive Care Units, Neonatal/statistics & numerical data , Placental Circulation/physiologyABSTRACT
In conversations, activated stereotypes about conversation partners can influence communicative behaviors. We investigate whether and how stereotypes about categorized conversation partners shape topic choice and the types of questions asked. In three experiments, participants imagined having a conversation. Gender or age stereotypes of the conversation partner were manipulated by means of a picture. Results show a higher likelihood of addressing conversation and question topics consistent with stereotypic expectancies about conversation partners. Moreover, stereotypes were reflected in subtle variations in question formulations. When questions address stereotype-consistent topics, they are likelier formulated with high-frequency adverbs and positive valence, while questions addressing stereotype-inconsistent topics more likely contain low-frequency adverbs and negative valence. In addition, Experiment 4 suggests that recipients are sensitive to detect that questions reflect stereotypes about themselves, which can influence the evaluation of the conversation and partner. We discuss the consequences of biased question asking for interpersonal conversation and stereotype maintenance.
ABSTRACT
BACKGROUND: Fetal growth restriction is strongly associated with impaired placentation and abnormal uteroplacental blood flow. Nitric oxide donors such as pentaerythritol tetranitrate are strong vasodilators and protect the endothelium. Recently, we demonstrated in a randomized controlled pilot study a 38% relative risk reduction for the development of fetal growth restriction or perinatal death following administration of pentaerythritol tetranitrate to pregnant women at risk, identified by impaired uterine perfusion at midgestation. Results of this monocenter study prompted the hypothesis that pentaerythritol tetranitrate might have an effect in pregnancies with compromised placental function as a secondary prophylaxis. OBJECTIVE: This study aimed to test the hypothesis that the nitric oxide donor pentaerythritol tetranitrate reduces fetal growth restriction and perinatal death in pregnant women with impaired placental perfusion at midgestation in a multicenter trial. STUDY DESIGN: In this multicenter, randomized, double-blind, placebo-controlled trial, 2 parallel groups of pregnant women presenting with a mean uterine artery pulsatility index >95th percentile at 19+0 to 22+6 weeks of gestation were randomized to 50-mg Pentalong or placebo twice daily. Participants were assigned to high- or low-risk groups according to their medical history before randomization was performed block-wise with a fixed block length stratified by center and risk group. The primary efficacy endpoint was the composite outcome of perinatal death or development of fetal growth restriction. Secondary endpoints were neonatal and maternal outcome parameters. RESULTS: Between August 2017 and March 2020, 317 participants were included in the study and 307 were analyzed. The cumulative incidence of the primary outcome was 41.1% in the pentaerythritol tetranitrate group and 45.5% in the placebo group (unadjusted relative risk, 0.90; 95% confidence interval, 0.69-1.17; adjusted relative risk, 0.90; 95% confidence interval, 0.69-1.17; P=.43). Secondary outcomes such as preterm birth (unadjusted relative risk, 0.73; 95% confidence interval, 0.56-0.94; adjusted relative risk, 0.73; 95% confidence interval, 0.56-0.94; P=.01) and pregnancy-induced hypertension (unadjusted relative risk, 0.65; 95% confidence interval, 0.46-0.93; adjusted relative risk, 0.65; 95% confidence interval, 0.46-0.92; P=0.01) were reduced. CONCLUSION: Our study failed to show an impact of pentaerythritol tetranitrate on the development of fetal growth restriction and perinatal death in pregnant women with impaired uterine perfusion at midgestation. Pentaerythritol tetranitrate significantly reduced secondary outcome parameters such as the incidence of preterm birth and pregnancy-induced hypertension in these pregnancies.
Subject(s)
Hypertension, Pregnancy-Induced , Pentaerythritol Tetranitrate , Perinatal Death , Premature Birth , Pregnancy , Female , Infant, Newborn , Humans , Pentaerythritol Tetranitrate/therapeutic use , Fetal Growth Retardation/etiology , Placenta/blood supply , Placentation , Perfusion/adverse effectsABSTRACT
Drug resistance and a dire lack of transmission-blocking antimalarials hamper malaria elimination. Here, we present the pantothenamide MMV693183 as a first-in-class acetyl-CoA synthetase (AcAS) inhibitor to enter preclinical development. Our studies demonstrate attractive drug-like properties and in vivo efficacy in a humanized mouse model of Plasmodium falciparum infection. The compound shows single digit nanomolar in vitro activity against P. falciparum and P. vivax clinical isolates, and potently blocks P. falciparum transmission to Anopheles mosquitoes. Genetic and biochemical studies identify AcAS as the target of the MMV693183-derived antimetabolite, CoA-MMV693183. Pharmacokinetic-pharmacodynamic modelling predict that a single 30 mg oral dose is sufficient to cure a malaria infection in humans. Toxicology studies in rats indicate a > 30-fold safety margin in relation to the predicted human efficacious exposure. In conclusion, MMV693183 represents a promising candidate for further (pre)clinical development with a novel mode of action for treatment of malaria and blocking transmission.
Subject(s)
Antimalarials , Folic Acid Antagonists , Malaria, Falciparum , Malaria, Vivax , Malaria , Animals , Antimalarials/pharmacology , Antimalarials/therapeutic use , Malaria/drug therapy , Malaria, Falciparum/drug therapy , Malaria, Vivax/drug therapy , Mice , Pantothenic Acid/analogs & derivatives , Plasmodium falciparum/genetics , RatsABSTRACT
The Apicomplexa phylum comprises thousands of distinct intracellular parasite species, including coccidians, haemosporidians, piroplasms, and cryptosporidia. These parasites are characterized by complex and divergent life cycles occupying a variety of host niches. Consequently, they exhibit distinct adaptations to the differences in nutritional availabilities, either relying on biosynthetic pathways or by salvaging metabolites from their host. Pantothenate (Pan, vitamin B5) is the precursor for the synthesis of an essential cofactor, coenzyme A (CoA), but among the apicomplexans, only the coccidian subgroup has the ability to synthesize Pan. While the pathway to synthesize CoA from Pan is largely conserved across all branches of life, there are differences in the redundancy of enzymes and possible alternative pathways to generate CoA from Pan. Impeding the scavenge of Pan and synthesis of Pan and CoA have been long recognized as potential targets for antimicrobial drug development, but in order to fully exploit these critical pathways, it is important to understand such differences. Recently, a potent class of pantothenamides (PanAms), Pan analogs, which target CoA-utilizing enzymes, has entered antimalarial preclinical development. The potential of PanAms to target multiple downstream pathways make them a promising compound class as broad antiparasitic drugs against other apicomplexans. In this review, we summarize the recent advances in understanding the Pan and CoA biosynthesis pathways, and the suitability of these pathways as drug targets in Apicomplexa, with a particular focus on the cyst-forming coccidian, Toxoplasma gondii, and the haemosporidian, Plasmodium falciparum.
Subject(s)
Antiparasitic Agents/pharmacology , Apicomplexa/metabolism , Apicomplexa/parasitology , Coenzyme A/biosynthesis , Pantothenic Acid/biosynthesis , Protozoan Infections , Animals , HumansABSTRACT
Plasmodium species have a single mitochondrion that is essential for their survival and has been successfully targeted by antimalarial drugs. Most mitochondrial proteins are imported into this organelle, and our picture of the Plasmodium mitochondrial proteome remains incomplete. Many data sources contain information about mitochondrial localization, including proteome and gene expression profiles, orthology to mitochondrial proteins from other species, coevolutionary relationships, and amino acid sequences, each with different coverage and reliability. To obtain a comprehensive, prioritized list of Plasmodium falciparum mitochondrial proteins, we rigorously analyzed and integrated eight data sets using Bayesian statistics into a predictive score per protein for mitochondrial localization. At a corrected false discovery rate of 25%, we identified 445 proteins with a sensitivity of 87% and a specificity of 97%. They include proteins that have not been identified as mitochondrial in other eukaryotes but have characterized homologs in bacteria that are involved in metabolism or translation. Mitochondrial localization of seven Plasmodium berghei orthologs was confirmed by epitope labeling and colocalization with a mitochondrial marker protein. One of these belongs to a newly identified apicomplexan mitochondrial protein family that in P. falciparum has four members. With the experimentally validated mitochondrial proteins and the complete ranked P. falciparum proteome, which we have named PlasmoMitoCarta, we present a resource to study unique proteins of Plasmodium mitochondria. IMPORTANCE The unique biology and medical relevance of the mitochondrion of the malaria parasite Plasmodium falciparum have made it the subject of many studies. However, we actually do not have a comprehensive assessment of which proteins reside in this organelle. Many omics data are available that are predictive of mitochondrial localization, such as proteomics data and expression data. Individual data sets are, however, rarely complete and can provide conflicting evidence. We integrated a wide variety of available omics data in a manner that exploits the relative strengths of the data sets. Our analysis gave a predictive score for the mitochondrial localization to each nuclear encoded P. falciparum protein and identified 445 likely mitochondrial proteins. We experimentally validated the mitochondrial localization of seven of the new mitochondrial proteins, confirming the quality of the complete list. These include proteins that have not been observed mitochondria before, adding unique mitochondrial functions to P. falciparum.
Subject(s)
Mitochondria/genetics , Mitochondrial Proteins/genetics , Plasmodium falciparum/growth & development , Plasmodium falciparum/genetics , Protozoan Proteins/genetics , Animals , Bayes Theorem , Female , Male , Mice , Mitochondrial Dynamics , Mitochondrial Proteins/metabolism , Proteomics , Protozoan Proteins/metabolism , Reproducibility of ResultsABSTRACT
BACKGROUND: Chronic corticosteroid treatment suppresses HPA-axis activity and might alter activity of 11ß hydroxysteroid dehydrogenases (11ß-HSD). We aimed to investigate whether the endogenous glucocorticoid production and 11ß-HSD activities are altered in prednisolone-treated renal transplant recipients (RTR) compared with healthy controls and whether this has implications for long-term survival in RTR. METHODS: In a longitudinal cohort of 693 stable RTR and 275 healthy controls, 24-hour urinary cortisol, cortisone, tetrahydrocorisol (THF), allotetrahydrocortisol (alloTHF), and tetrahydrocortisone (THE) were measured using liquid chromatography tandem-mass spectrometry. Twenty-four-hour urinary excretion of cortisol and metabolites were used as measures of endogenous glucocorticoid production; (THF + alloTHF)/THE and cortisol/cortisone ratios were used as measures of 11ß-HSD activity. RESULTS: Urinary cortisol and metabolite excretion were significantly lower in RTR compared with healthy controls (P < .001), whereas (THF + alloTHF)/THE and cortisol/cortisone ratios were significantly higher (P < .001 and P = .002). Lower total urinary metabolite excretion and higher urinary (THF + alloTHF)/THE ratios were associated with increased risk of mortality, independent of age, sex, estimated glomerular filtration rate, C-reactive protein, body surface area, and daily prednisolone dose, respectively. CONCLUSIONS: Endogenous glucocorticoid production and 11ß-HSD activities are altered in prednisolone-treated RTR. Decreased total urinary endogenous glucocorticoid metabolite excretion and increased urinary (THF + alloTHF)/THE ratios are associated with increased risk of mortality.
Subject(s)
Cortisone , Kidney Transplantation , Glucocorticoids/therapeutic use , Humans , Prednisolone/therapeutic use , TetrahydrocortisoneABSTRACT
BACKGROUND: According to cognitive behavioural theory, cognitive factors (i.e. underlying general dysfunctional beliefs and (situation) specific illness beliefs) are theorized to lead to outcomes like anxiety and depression. In clinical practice, general dysfunctional beliefs are generally not tackled directly in short-term-therapy. AIMS: The goal of the present study was to investigate the associations of general versus specific illness beliefs on anxiety and depressive symptoms and psychiatric disorders among a subgroup of patients with inflammatory bowel disease (IBD) with poor mental quality of life (QoL). METHOD: This study concerns cross-sectional data, collected at baseline from a randomized clinical trial. One hundred and eighteen patients, recruited at four Dutch hospitals, with poor QoL (score ≤23 on the mental health subscale of the Short-Form 36-item Health-Survey; SF-36) were included. General dysfunctional beliefs were measured by the Dysfunctional Attitude Scale (DAS), specific illness beliefs by the Illness Perceptions Questionnaire-Revised (IPQ-R), anxiety and depressive symptoms by the Hospital Anxiety and Depression Scale (HADS), and psychiatric disorders by the Structured Clinical Interview for DSM-IV Axis-I Disorders (SCID-I). RESULTS: Univariate analyses showed associations between the level of anxiety and/or depression and general dysfunctional beliefs and four specific illness beliefs (consequences, personal control, emotional representations and treatment control). Among patients with IBD with psychiatric disorders, only the DAS was significantly associated with anxiety and depression (DAS added to IPQ-R and IPQ-R added to DAS). CONCLUSIONS: Psychological interventions may have to target general dysfunctional beliefs of patients with IBD with co-morbid psychiatric disorders to be effective. These patients with IBD are especially in need of psychological treatment.
Subject(s)
Anxiety Disorders/psychology , Colitis, Ulcerative/psychology , Crohn Disease/psychology , Culture , Depressive Disorder/psychology , Quality of Life/psychology , Self Concept , Adult , Anxiety Disorders/diagnosis , Anxiety Disorders/therapy , Cognitive Behavioral Therapy , Colitis, Ulcerative/therapy , Combined Modality Therapy , Comorbidity , Crohn Disease/therapy , Cross-Sectional Studies , Depressive Disorder/diagnosis , Depressive Disorder/therapy , Female , Humans , Illness Behavior , Male , Middle Aged , Surveys and QuestionnairesABSTRACT
Dipeptidyl aminopeptidases (DPAPs) are cysteine proteases that cleave dipeptides from the N-terminus of protein substrates and have been shown to play important roles in many pathologies including parasitic diseases such as malaria, toxoplasmosis and Chagas's disease. Inhibitors of the mammalian homologue cathepsin C have been used in clinical trials as potential drugs to treat chronic inflammatory disorders, thus proving that these enzymes are druggable. In Plasmodium species, DPAPs play important functions at different stages of parasite development, thus making them potential antimalarial targets. Most DPAP inhibitors developed to date are peptide-based or peptidomimetic competitive inhibitors. Here, we used a high throughput screening approach to identify novel inhibitor scaffolds that block the activity of Plasmodium falciparum DPAP1. Most of the hits identified in this screen also inhibit Plasmodium falciparum DPAP3, cathepsin C, and to a lesser extent other malarial clan CA proteases, indicating that these might be general DPAP inhibitors. Interestingly, our mechanism of inhibition studies indicate that most hits are allosteric inhibitors, which opens a completely new strategy to inhibit these enzymes, study their biological function, and potentially develop new inhibitors as starting points for drug development.
Subject(s)
Antimalarials/pharmacology , Cysteine Proteases , Cysteine Proteinase Inhibitors/pharmacology , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/antagonists & inhibitors , Plasmodium falciparum/drug effects , Plasmodium falciparum/enzymology , Protozoan Proteins/antagonists & inhibitors , Antimalarials/toxicity , Cells, Cultured , Drug Evaluation, Preclinical , HumansABSTRACT
Malaria eradication is critically dependent on new therapeutics that target resistant Plasmodium parasites and block transmission of the disease. Here, we report that pantothenamide bioisosteres were active against blood-stage Plasmodium falciparum parasites and also blocked transmission of sexual stages to the mosquito vector. These compounds were resistant to degradation by serum pantetheinases, showed favorable pharmacokinetic properties, and cleared parasites in a humanized mouse model of P. falciparum infection. Metabolomics revealed that coenzyme A biosynthetic enzymes converted pantothenamides into coenzyme A analogs that interfered with parasite acetyl-coenzyme A anabolism. Resistant parasites generated in vitro showed mutations in acetyl-coenzyme A synthetase and acyl-coenzyme A synthetase 11. Introduction and reversion of these mutations in P. falciparum using CRISPR-Cas9 gene editing confirmed the roles of these enzymes in the sensitivity of the malaria parasites to pantothenamides. These pantothenamide compounds with a new mode of action may have potential as drugs against malaria parasites.
Subject(s)
Acetyl Coenzyme A/biosynthesis , Antimalarials/pharmacology , Biosynthetic Pathways/drug effects , Pantothenic Acid/analogs & derivatives , Pantothenic Acid/pharmacology , Plasmodium falciparum/metabolism , Animals , Antimalarials/chemistry , Antimalarials/pharmacokinetics , Disease Models, Animal , Drug Resistance/drug effects , Humans , Malaria, Falciparum/parasitology , Malaria, Falciparum/transmission , Male , Mice, Inbred BALB C , Mutation/genetics , Pantothenic Acid/chemistry , Parasitemia/drug therapy , Parasites/drug effects , Parasites/metabolism , Protozoan Proteins/genetics , Reproduction, Asexual/drug effects , Treatment Outcome , Trophozoites/drug effects , Trophozoites/metabolismABSTRACT
Malarial dipeptidyl aminopeptidases (DPAPs) are cysteine proteases important for parasite development thus making them attractive drug targets. In order to develop inhibitors specific to the parasite enzymes, it is necessary to map the determinants of substrate specificity of the parasite enzymes and its mammalian homologue cathepsin C (CatC). Here, we screened peptide-based libraries of substrates and covalent inhibitors to characterize the differences in specificity between parasite DPAPs and CatC, and used this information to develop highly selective DPAP1 and DPAP3 inhibitors. Interestingly, while the primary amino acid specificity of a protease is often used to develop potent inhibitors, we show that equally potent and highly specific inhibitors can be developed based on the sequences of nonoptimal peptide substrates. Finally, our homology modelling and docking studies provide potential structural explanations of the differences in specificity between DPAP1, DPAP3, and CatC, and between substrates and inhibitors in the case of DPAP3. Overall, this study illustrates that focusing the development of protease inhibitors solely on substrate specificity might overlook important structural features that can be exploited to develop highly potent and selective compounds.
Subject(s)
Amino Acids/chemistry , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/metabolism , Erythrocytes/parasitology , Malaria, Falciparum/parasitology , Peptide Fragments/metabolism , Plasmodium falciparum/growth & development , Protease Inhibitors/pharmacology , Erythrocytes/drug effects , Erythrocytes/metabolism , Humans , Malaria, Falciparum/drug therapy , Malaria, Falciparum/metabolism , Models, Molecular , Molecular Structure , Plasmodium falciparum/drug effects , Plasmodium falciparum/metabolism , Protein Conformation , Substrate SpecificityABSTRACT
OBJECTIVE: To learn how to configure a patient communication aid (PCA) to facilitate shared decision-making (SDM) about treatment for advanced cancer. METHODS: The PCA consists of education about SDM, a question prompt list, and values clarification methods. Study 1. A first version was presented to 13 patients, 8 relatives and 14 bereaved relatives in interviews. Study 2. A second version was used by 18 patients in a pilot study. Patients and oncologists were interviewed, patients were surveyed, and consultations were audio-recorded. RESULTS: Respondents reported that the aid facilitated patient control over information, raised choice awareness and promoted elaboration. Risks were identified, most importantly that the aid might upset patients. Also, some respondents reported that the PCA did not, or would not support decision making because they felt sufficiently competent, did not perceive a role for themselves, or did not perceive that the decision required elaboration. CONCLUSIONS: Opinions on the usefulness of the PCA varied. It was challenging to raise awareness about the presence of a choice, and to find a balance between comprehensive information and sensitivity. PRACTICE IMPLICATIONS: A future study should demonstrate whether the PCA can improve SDM, and whether this effect is stronger when oncologists receive training.
Subject(s)
Decision Making , Neoplasms/therapy , Patient Education as Topic , Patient Participation , Physician-Patient Relations , Adult , Communication , Female , Humans , Male , Middle Aged , Neoplasms/pathology , Neoplasms/psychology , Palliative Care/psychology , Pilot Projects , Program EvaluationABSTRACT
CONTEXT: Derangement of 11-ß hydroxysteroid dehydrogenase type 1 and type 2 (11ß-HSD1 and 11ß-HSD2), which regulate intracellular cortisol production, has been suggested in both type 2 diabetes (T2D) and chronic kidney disease (CKD). However, activity of 11ß-HSD enzymes in patients with T2D and CKD has never been assessed. OBJECTIVES: To compare 11ß-HSD activities between patients with T2D and healthy controls, and assess whether in T2D, renal function is associated with 11ß-HSD activities. DESIGN: Cross-sectional analysis in the Diabetes and Lifestyle Cohort Twente (DIALECT-1). SETTING: Referral center for T2D. PATIENTS: Patient with T2D [n = 373, age 64 ± 9 years, 58% men, 26% of patients estimated glomerular filtration rate (eGFR) <60 mL/min·1.73 m2] and healthy controls (n = 275, age 53 ± 11 years, 48% men). MEAN OUTCOME MEASURE: We measured cortisol, cortisone, and metabolites [tetrahydrocortisol (THF), allo-THF (aTHF), and tetrahydrocortisone (THE)] in 24-hour urine samples. Whole body 11ß-HSD and 11ß-HSD2 activities were calculated as the urinary (THF + aTHF)/THE and cortisol/cortisone ratios, respectively. RESULTS: Patients with T2D had a higher (THF + aTHF)/THE ratio [1.02 (0.84 to 1.27) vs 0.94 (0.79 to 1.0), P < 0.001] and cortisol/cortisone ratio [0.70 (0.58 to 0.83) vs 0.63 (0.54 to 0.74), P < 0.001] than healthy controls. In T2D, lower eGFR was associated with a higher (THF + aTHF)/THE ratio (ß = -0.35, P < 0.001), and a higher cortisol/cortisone ratio (ß = -0.16, P = 0.001). CONCLUSIONS: In this real-life secondary care setting of patients with T2D, 11ß-HSD enzymes activities were shifted to higher intracellular cortisol production in T2D, which was further aggravated in patients with CKD. Prospective analyses are warranted to investigate causality of these associations.
ABSTRACT
Glioblastoma (GBM) is the most aggressive and an incurable type of brain cancer. Human cytomegalovirus (HCMV) DNA and encoded proteins, including the chemokine receptor US28, have been detected in GBM tumors. US28 displays constitutive activity and is able to bind several human chemokines, leading to the activation of various proliferative and inflammatory signaling pathways. Here we show that HCMV, through the expression of US28, significantly enhanced the growth of 3D spheroids of U251- and neurospheres of primary glioblastoma cells. Moreover, US28 expression accelerated the growth of glioblastoma cells in an orthotopic intracranial GBM-model in mice. We developed highly potent and selective US28-targeting nanobodies, which bind to the extracellular domain of US28 and detect US28 in GBM tissue. The nanobodies inhibited chemokine binding and reduced the constitutive US28-mediated signaling with nanomolar potencies and significantly impaired HCMV/US28-mediated tumor growth in vitro and in vivo. This study emphasizes the oncomodulatory role of HCMV-encoded US28 and provides a potential therapeutic approach for HCMV-positive tumors using the nanobody technology.
Subject(s)
Brain Neoplasms/genetics , Cell Proliferation/genetics , Cytomegalovirus/genetics , Glioblastoma/genetics , Receptors, Chemokine/genetics , Viral Proteins/genetics , Animals , Brain Neoplasms/pathology , COS Cells , Cell Line , Chlorocebus aethiops , Female , Glioblastoma/pathology , HEK293 Cells , Humans , Mice , Mice, Nude , NIH 3T3 Cells , Receptors, Virus/genetics , Signal Transduction/geneticsABSTRACT
Parasite egress from infected erythrocytes and invasion of new red blood cells are essential processes for the exponential asexual replication of the malaria parasite. These two tightly coordinated events take place in less than a minute and are in part regulated and mediated by proteases. Dipeptidyl aminopeptidases (DPAPs) are papain-fold cysteine proteases that cleave dipeptides from the N-terminus of protein substrates. DPAP3 was previously suggested to play an essential role in parasite egress. However, little is known about its enzymatic activity, intracellular localization, or biological function. In this study, we recombinantly expressed DPAP3 and demonstrate that it has indeed dipeptidyl aminopeptidase activity, but contrary to previously studied DPAPs, removal of its internal prodomain is not required for activation. By combining super resolution microscopy, time-lapse fluorescence microscopy, and immunoelectron microscopy, we show that Plasmodium falciparum DPAP3 localizes to apical organelles that are closely associated with the neck of the rhoptries, and from which DPAP3 is secreted immediately before parasite egress. Using a conditional knockout approach coupled to complementation studies with wild type or mutant DPAP3, we show that DPAP3 activity is important for parasite proliferation and critical for efficient red blood cell invasion. We also demonstrate that DPAP3 does not play a role in parasite egress, and that the block in egress phenotype previously reported for DPAP3 inhibitors is due to off target or toxicity effects. Finally, using a flow cytometry assay to differentiate intracellular parasites from extracellular parasites attached to the erythrocyte surface, we show that DPAP3 is involved in the initial attachment of parasites to the red blood cell surface. Overall, this study establishes the presence of a DPAP3-dependent invasion pathway in malaria parasites.
Subject(s)
Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/metabolism , Malaria, Falciparum/parasitology , Plasmodium falciparum/enzymology , Animals , Cysteine Proteases/metabolism , Erythrocytes/microbiology , Erythrocytes/parasitology , Host-Parasite Interactions , Malaria, Falciparum/metabolism , Malaria, Falciparum/pathology , Merozoites/metabolism , Merozoites/physiology , Organelles/metabolism , Peptide Hydrolases/metabolism , Plasmodium falciparum/genetics , Plasmodium falciparum/metabolism , Plasmodium falciparum/pathogenicity , Proteolysis , Protozoan Proteins/metabolismABSTRACT
Chronic prednisolone treatment in renal transplant recipients (RTR) causes metabolic abnormalities, which cluster in the metabolic syndrome (MS). It also suppresses the hypothalamic-pituitaryadrenal (HPA)-axis. We investigated whether HPA-axis suppression, as measured by 24h urinary cortisol excretion, is associated with presence of the MS and its individual components, in outpatient RTR with a functioning graft for >1year. Urinary cortisol was measured in 24h urine, using LC-MS/MS (LOQ 0.30nmol/L). We included 563 RTR (age 51±12years; 54% male) at median 6.0 [IQR, 2.6-11.5] years post-transplantation. MS was present in 439/563 RTR (78%). Median 24h urinary cortisol excretion was 2.0 [IQR, 0.9-5.1]nmol/24h. Twenty-four hour urinary cortisol excretion was independently associated with MS presence (OR=0.80 [95% CI, 0.66-0.98], P=0.02). It was also independently associated with bodyweight (st.ß=-0.11, P=0.007), waist circumference (st.ß=-0.10, P=0.01), BMI (st.ß=-0.14, P=0.001), fasting triglycerides (st.ß=-0.15, P=0.001), diabetes (st.ß=-0.12, P=0.005), and number of antihypertensives used (st.ß=-0.13, P=0.003). Suppressed HPA-axis activity, as reflected by decreased 24h urinary cortisol excretion, is associated with higher prevalence of MS and its individual components (i.e. central obesity, dyslipidemia, diabetes, hypertension) in prednisolone-treated RTR. Assessment of 24h urinary cortisol excretion by LC-MS/MS may be a tool to monitor metabolic side-effects of prednisolone in RTR.
Subject(s)
Hydrocortisone/urine , Kidney Transplantation , Metabolic Syndrome/chemically induced , Metabolic Syndrome/urine , Prednisolone/adverse effects , Female , Humans , Hypothalamus/drug effects , Male , Middle Aged , Pituitary Gland/drug effects , Time FactorsABSTRACT
Tryptophan is metabolized along the kynurenine pathway, initially to kynurenine, and subsequently to cytotoxic 3-hydroxykynurenine. There is increasing interest in this pathway because of its proinflammatory nature, and drugs interfering in it have received increasing attention. We aimed to investigate whether serum and urinary parameters of the tryptophan/kynurenine pathway, and particularly cytotoxic 3-hydroxykynurenine, are associated with systemic inflammation and long-term outcome in renal transplant recipients (RTR). Data were collected in outpatient RTR with a functioning graft for >1 yr. Tryptophan, kynurenine, and 3-hydroxykynurenine in serum and urine were measured using LC-MS/MS. A total of 561 RTR (age: 51 ± 12 yr; 56% male) were included at a median of 6.0 (2.6-11.6) yr posttransplantation. Baseline median serum tryptophan was 40.0 (34.5-46.0) µmol/l, serum kynurenine was 1.8 (1.4-2.2) µmol/l, and serum 3-hydroxykynurenine was 42.2 (31.0-61.7) nmol/l. Serum kynurenine and 3-hydroxykynurenine were strongly associated with parameters of systemic inflammation. During follow-up for 7.0 (6.2-7.5) yr, 51 RTR (9%) developed graft failure and 120 RTR (21%) died. Both serum kynurenine and 3-hydroxykynurenine were independently associated with graft failure [HR 1.72 (1.23-2.41), P = 0.002; and HR 2.03 (1.42-2.90), P < 0.001]. Serum 3-hydroxykynurenine was also independently associated with mortality [HR 1.37 (1.08-1.73), P = 0.01], whereas serum kynurenine was not. Urinary tryptophan/kynurenine pathway parameters were not associated with outcome. Of tryptophan metabolites, serum 3-hydroxykynurenine is cross-sectionally most strongly and consistently associated with systemic inflammation and prospectively with adverse long-term outcome after kidney transplantation. Serum 3-hydroxykynurenine may be an interesting biomarker and target for the evaluation of drugs interfering in the tryptophan/kynurenine pathway.
Subject(s)
Inflammation Mediators/blood , Inflammation/blood , Kidney Transplantation/adverse effects , Kynurenine/analogs & derivatives , Tryptophan/blood , Adult , Biomarkers/blood , Chromatography, Liquid , Female , Graft Rejection/blood , Graft Rejection/etiology , Graft Rejection/urine , Graft Survival , Humans , Inflammation/diagnosis , Inflammation/etiology , Inflammation/urine , Inflammation Mediators/urine , Kynurenine/blood , Kynurenine/urine , Longitudinal Studies , Male , Middle Aged , Predictive Value of Tests , Prospective Studies , Risk Factors , Tandem Mass Spectrometry , Time Factors , Treatment Outcome , Tryptophan/urine , Vascular Diseases/blood , Vascular Diseases/etiology , Vascular Diseases/urineABSTRACT
Chemotherapeutics, including the platinum compounds oxaliplatin (OXP) and cisplatin (CDDP), are standard care of treatment for cancer. Although chemotherapy has long been considered immunosuppressive, evidence now suggests that certain cytotoxic agents can efficiently stimulate antitumor responses, through the induction of a form of apoptosis, called immunogenic cell death (ICD). ICD is characterized by exposure of calreticulin and heat shock proteins (HSPs), secretion of ATP and release of high-mobility group box 1 (HMGB1). Proper activation of the immune system relies on the integration of these signals by dendritic cells (DCs). Studies on the crucial role of DCs, in the context of ICD, have been performed using mouse models or human in vitro-generated monocyte-derived DCs (moDCs), which do not fully recapitulate the in vivo situation. Here, we explore the effect of platinum-induced ICD on phenotype and function of human blood circulating DCs. Tumor cells were treated with OXP or CDDP and induction of ICD was investigated. We show that both platinum drugs triggered translocation of calreticulin and HSP70, as well as the release of ATP and HMGB1. Platinum treatment increased phagocytosis of tumor fragments by human blood DCs and enhanced phenotypic maturation of blood myeloid and plasmacytoid DCs. Moreover, upon interaction with platinum-treated tumor cells, CD1c(+) DCs efficiently stimulated allogeneic proliferation of T lymphocytes. Together, our observations indicate that platinum-treated tumor cells may exert an active stimulatory effect on human blood DCs. In particular, these data suggest that CD1c(+) DCs are critical mediators of immune responses induced by ICD.
ABSTRACT
Kaposi's sarcoma-associated herpesvirus (KSHV) encodes the constitutively active G protein-coupled receptor ORF74, which is expressed on the surface of infected host cells and has been linked to the development of the angioproliferative tumor Kaposi's sarcoma. Furthermore, the insulin-like growth factor (IGF)-1 receptor, a receptor tyrosine kinase, also plays an essential role in Kaposi's sarcoma growth and survival. In this study we examined the effect of the constitutively active viral receptor ORF74 on human IGF-1R signaling. Constitutive and CXCL1-induced ORF74 signaling did not transactivate IGF-1R. In contrast, IGF-1 stimulated phospholipase C (PLC) activation in an ORF74-dependent manner without affecting chemokine binding to ORF74. Inhibition of constitutive ORF74 activity by mutagenesis or the inverse agonist CXCL10, or neutralizing IGF-1R with an antibody or silencing IGF-1R expression using siRNA inhibited PLC activation by IGF-1. Transactivation of ORF74 in response to IGF-1 occurred independently of Src, PI3K, and secreted ORF74 ligands. Furthermore, tyrosine residues in the carboxyl-terminus and intracellular loop 2 of ORF74 are not essential for IGF-1-induced PLC activation. Interestingly, PLC activation in response to IGF-1 is specific for ORF74 as IGF-1 was unable to activate PLC in cells expressing the constitutively active human cytomegalovirus (HCMV)-encoded GPCR US28. Interestingly, IGF-1 does not induce ß-arrestin recruitment to ORF74. The proximity ligation assay revealed close proximity between ORF74 and IGF-1R on the cell surface, but a physical interaction was not confirmed by co-immunoprecipitation. Unmasking IGF-1R signaling to PLC in response to IGF-1 is a previously unrecognized action of ORF74.