Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Proc Biol Sci ; 291(2025): 20240535, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38917861

RESUMO

Empirical data relating body mass to immune defence against infections remain limited. Although the metabolic theory of ecology predicts that larger organisms would have weaker immune responses, recent studies have suggested that the opposite may be true. These discoveries have led to the safety factor hypothesis, which proposes that larger organisms have evolved stronger immune defences because they carry greater risks of exposure to pathogens and parasites. In this study, we simulated sepsis by exposing blood from nine primate species to a bacterial lipopolysaccharide (LPS), measured the relative expression of immune and other genes using RNAseq, and fitted phylogenetic models to determine how gene expression was related to body mass. In contrast to non-immune-annotated genes, we discovered hypermetric scaling in the LPS-induced expression of innate immune genes, such that large primates had a disproportionately greater increase in gene expression of immune genes compared to small primates. Hypermetric immune gene expression appears to support the safety factor hypothesis, though this pattern may represent a balanced evolutionary mechanism to compensate for lower per-transcript immunological effectiveness. This study contributes to the growing body of immune allometry research, highlighting its importance in understanding the complex interplay between body size and immunity over evolutionary timescales.


Assuntos
Primatas , Sepse , Transcriptoma , Animais , Sepse/veterinária , Sepse/imunologia , Lipopolissacarídeos , Imunidade Inata , Tamanho Corporal , Filogenia
3.
Nat Commun ; 15(1): 3747, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38702310

RESUMO

In malaria parasites, the regulation of mRNA translation, storage and degradation during development and life-stage transitions remains largely unknown. Here, we functionally characterized the DEAD-box RNA helicase PfDOZI in P. falciparum. Disruption of pfdozi enhanced asexual proliferation but reduced sexual commitment and impaired gametocyte development. By quantitative transcriptomics, we show that PfDOZI is involved in the regulation of invasion-related genes and sexual stage-specific genes during different developmental stages. PfDOZI predominantly participates in processing body-like mRNPs in schizonts but germ cell granule-like mRNPs in gametocytes to impose opposing actions of degradation and protection on different mRNA targets. We further show the formation of stress granule-like mRNPs during nutritional deprivation, highlighting an essential role of PfDOZI-associated mRNPs in stress response. We demonstrate that PfDOZI participates in distinct mRNPs to maintain mRNA homeostasis in response to life-stage transition and environmental changes by differentially executing post-transcriptional regulation on the target mRNAs.


Assuntos
RNA Helicases DEAD-box , Plasmodium falciparum , Proteínas de Protozoários , RNA Mensageiro , RNA Helicases DEAD-box/metabolismo , RNA Helicases DEAD-box/genética , Plasmodium falciparum/genética , Plasmodium falciparum/metabolismo , Plasmodium falciparum/crescimento & desenvolvimento , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Ribonucleoproteínas/metabolismo , Ribonucleoproteínas/genética , Estágios do Ciclo de Vida/genética , RNA de Protozoário/metabolismo , RNA de Protozoário/genética , Estabilidade de RNA , Humanos , Malária Falciparum/parasitologia
4.
Emerg Infect Dis ; 30(6): 1214-1217, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38662728

RESUMO

During May-July 2023, a cluster of 7 patients at local hospitals in Florida, USA, received a diagnosis of Plasmodium vivax malaria. Whole-genome sequencing of the organism from 4 patients and phylogenetic analysis with worldwide representative P. vivax genomes indicated probable single parasite introduction from Central/South America.


Assuntos
Malária Vivax , Filogenia , Plasmodium vivax , Humanos , Malária Vivax/epidemiologia , Malária Vivax/parasitologia , Malária Vivax/diagnóstico , Florida/epidemiologia , Plasmodium vivax/genética , Masculino , Sequenciamento Completo do Genoma , Feminino , Adulto , Pessoa de Meia-Idade
5.
Life Sci Alliance ; 7(7)2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38649187

RESUMO

All cancer cells reprogram metabolism to support aberrant growth. Here, we report that cancer cells employ and depend on imbalanced and dynamic heme metabolic pathways, to accumulate heme intermediates, that is, porphyrins. We coined this essential metabolic rewiring "porphyrin overdrive" and determined that it is cancer-essential and cancer-specific. Among the major drivers are genes encoding mid-step enzymes governing the production of heme intermediates. CRISPR/Cas9 editing to engineer leukemia cell lines with impaired heme biosynthetic steps confirmed our whole-genome data analyses that porphyrin overdrive is linked to oncogenic states and cellular differentiation. Although porphyrin overdrive is absent in differentiated cells or somatic stem cells, it is present in patient-derived tumor progenitor cells, demonstrated by single-cell RNAseq, and in early embryogenesis. In conclusion, we identified a dependence of cancer cells on non-homeostatic heme metabolism, and we targeted this cancer metabolic vulnerability with a novel "bait-and-kill" strategy to eradicate malignant cells.


Assuntos
Sistemas CRISPR-Cas , Heme , Porfirinas , Humanos , Heme/metabolismo , Porfirinas/metabolismo , Porfirinas/farmacologia , Linhagem Celular Tumoral , Neoplasias/metabolismo , Neoplasias/genética , Redes e Vias Metabólicas/genética , Diferenciação Celular/genética , Edição de Genes , Animais , Camundongos
6.
Commun Biol ; 6(1): 659, 2023 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-37349497

RESUMO

Protein arginine methyltransferases (PRMTs) regulate many important cellular processes, such as transcription and RNA processing in model organisms but their functions in human malaria parasites are not elucidated. Here, we characterize PfPRMT5 in Plasmodium falciparum, which catalyzes symmetric dimethylation of histone H3 at R2 (H3R2me2s) and R8, and histone H4 at R3 in vitro. PfPRMT5 disruption results in asexual stage growth defects primarily due to lower invasion efficiency of the merozoites. Transcriptomic analysis reveals down-regulation of many transcripts related to invasion upon PfPRMT5 disruption, in agreement with H3R2me2s being an active chromatin mark. Genome-wide chromatin profiling detects extensive H3R2me2s marking of genes of different cellular processes, including invasion-related genes in wildtype parasites and PfPRMT5 disruption leads to the depletion of H3R2me2s. Interactome studies identify the association of PfPRMT5 with invasion-related transcriptional regulators such as AP2-I, BDP1, and GCN5. Furthermore, PfPRMT5 is associated with the RNA splicing machinery, and PfPRMT5 disruption caused substantial anomalies in RNA splicing events, including those for invasion-related genes. In summary, PfPRMT5 is critical for regulating parasite invasion and RNA splicing in this early-branching eukaryote.


Assuntos
Merozoítos , Plasmodium falciparum , Animais , Humanos , Plasmodium falciparum/metabolismo , Merozoítos/genética , Proteína-Arginina N-Metiltransferases/genética , Proteína-Arginina N-Metiltransferases/metabolismo , Histonas/genética , Histonas/metabolismo , Cromatina/metabolismo
7.
Nucleic Acids Res ; 51(8): 3918-3933, 2023 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-37026483

RESUMO

DNA modifications are critical in fine-tuning the biological processes in model organisms. However, the presence of cytosine methylation (5mC) and the function of the putative DNA methyltransferase, PfDNMT2, in the human malaria pathogen, Plasmodium falciparum, remain controversial. Here, we revisited the 5mC in the parasite genome and the function of PfDNMT2. Low levels of genomic 5mC (0.1-0.2%) during asexual development were identified using a sensitive mass spectrometry procedure. Native PfDNMT2 displayed substantial DNA methylation activities, and disruption or overexpression of PfDNMT2 resulted in reduced or elevated genomic 5mC levels, respectively. PfDNMT2 disruption led to an increased proliferation phenotype, with the parasites having an extended schizont stage and producing a higher number of progenies. Consistent with PfDNMT2's interaction with an AP2 domain-containing transcription factor, transcriptomic analyses revealed that PfDNMT2 disruption led to a drastic alteration in the expression of many genes, some of which provided the molecular basis of enhanced proliferation after PfDNMT2 disruption. Furthermore, levels of tRNAAsp and its methylation rate at position C38, and the translation of a reporter containing an aspartate repeat were significantly reduced after PfDNMT2 disruption, while the levels of tRNAAsp and its C38 methylation were restored after complementation of PfDNMT2. Our study sheds new light on the dual function of PfDNMT2 during P. falciparum asexual development.


Assuntos
Metiltransferases , Plasmodium falciparum , Proteínas de Protozoários , DNA/genética , Metilação de DNA , Metiltransferases/genética , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , RNA de Transferência de Ácido Aspártico/genética
8.
Microbiol Spectr ; 11(3): e0501422, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-37067430

RESUMO

The antimalarial activity of the frontline drug artemisinin involves generation of reactive oxygen species (ROS) leading to oxidative damage of parasite proteins. To achieve homeostasis and maintain protein quality control in the overwhelmed parasite, the ubiquitin-proteasome system kicks in. Even though molecular markers for artemisinin resistance like pfkelch13 have been identified, the intricate network of mechanisms driving resistance remains to be elucidated. Here, we report a forward genetic screening strategy that enables a broader identification of genetic factors responsible for altering sensitivity to dihydroartemisinin (DHA) and a proteasome inhibitor, bortezomib (BTZ). Using a library of isogenic piggyBac mutants in P. falciparum, we defined phenotype-genotype associations influencing drug responses and highlighted shared mechanisms between the two processes, which mainly included proteasome-mediated degradation and the lipid metabolism genes. Additional transcriptomic analysis of a DHA/BTZ-sensitive piggyBac mutant showed it is possible to find differences between the two response mechanisms on the specific components for regulation of the exportome. Our results provide further insight into the molecular mechanisms of antimalarial drug resistance. IMPORTANCE Malaria control is seriously threatened by the emergence and spread of Plasmodium falciparum resistance to the leading antimalarial, artemisinin. The potent killing activity of artemisinin results from oxidative damage unleashed by free heme activation released by hemoglobin digestion. Although the ubiquitin-proteasome system is considered critical for parasite survival of this toxicity, the diverse genetic changes linked to artemisinin resistance are complex and, so far, have not included the ubiquitin-proteasome system. In this study, we use a systematic forward genetic approach by screening a library of P. falciparum random piggyBac mutants to decipher the genetic factors driving malaria parasite responses to the oxidative stress caused by antimalarial drugs. This study compares phenotype-genotype associations influencing dihydroartemisinin responses with the proteasome inhibitor bortezomib to delineate the role of ubiquitin-proteasome system. Our study highlights shared and unique pathways from the complex array of molecular processes critical for P. falciparum survival resulting from the oxidative damage of artemisinin.


Assuntos
Antimaláricos , Artemisininas , Malária Falciparum , Malária , Humanos , Plasmodium falciparum , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Bortezomib/farmacologia , Bortezomib/metabolismo , Bortezomib/uso terapêutico , Metabolismo dos Lipídeos , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Complexo de Endopeptidases do Proteassoma/farmacologia , Inibidores de Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Inibidores de Proteassoma/uso terapêutico , Proteínas de Protozoários/genética , Artemisininas/farmacologia , Malária Falciparum/tratamento farmacológico , Resistência a Medicamentos/genética , Ubiquitina/metabolismo
9.
Nat Commun ; 13(1): 4370, 2022 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-35902581

RESUMO

Treatment with ß-lactam antibiotics, particularly cephalosporins, is a major risk factor for Clostridioides difficile infection. These broad-spectrum antibiotics irreversibly inhibit penicillin-binding proteins (PBPs), which are serine-based enzymes that assemble the bacterial cell wall. However, C. difficile has four different PBPs (PBP1-3 and SpoVD) with various roles in growth and spore formation, and their specific links to ß-lactam resistance in this pathogen are underexplored. Here, we show that PBP2 (known to be essential for vegetative growth) is the primary bactericidal target for ß-lactams in C. difficile. PBP2 is insensitive to cephalosporin inhibition, and this appears to be the main basis for cephalosporin resistance in this organism. We determine crystal structures of C. difficile PBP2, alone and in complex with ß-lactams, revealing unique features including ligand-induced conformational changes and an active site Zn2+-binding motif that influences ß-lactam binding and protein stability. The Zn2+-binding motif is also present in C. difficile PBP3 and SpoVD (which are known to be essential for sporulation), as well as in other bacterial taxa including species living in extreme environments and the human gut. We speculate that this thiol-containing motif and its cognate Zn2+ might function as a redox sensor to regulate cell wall synthesis for survival in adverse or anaerobic environments.


Assuntos
Resistência às Cefalosporinas , Clostridioides difficile , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Cefalosporinas/farmacologia , Clostridioides , Humanos , Serina , Zinco , beta-Lactamas/farmacologia
10.
PLoS Pathog ; 17(8): e1009351, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34403450

RESUMO

The histone acetyltransferase GCN5-associated SAGA complex is evolutionarily conserved from yeast to human and functions as a general transcription co-activator in global gene regulation. In this study, we identified a divergent GCN5 complex in Plasmodium falciparum, which contains two plant homeodomain (PHD) proteins (PfPHD1 and PfPHD2) and a plant apetela2 (AP2)-domain transcription factor (PfAP2-LT). To dissect the functions of the PfGCN5 complex, we generated parasite lines with either the bromodomain in PfGCN5 or the PHD domain in PfPHD1 deleted. The two deletion mutants closely phenocopied each other, exhibiting significantly reduced merozoite invasion of erythrocytes and elevated sexual conversion. These domain deletions caused dramatic decreases not only in histone H3K9 acetylation but also in H3K4 trimethylation, indicating synergistic crosstalk between the two euchromatin marks. Domain deletion in either PfGCN5 or PfPHD1 profoundly disturbed the global transcription pattern, causing altered expression of more than 60% of the genes. At the schizont stage, these domain deletions were linked to specific down-regulation of merozoite genes involved in erythrocyte invasion, many of which contain the AP2-LT binding motif and are also regulated by AP2-I and BDP1, suggesting targeted recruitment of the PfGCN5 complex to the invasion genes by these specific factors. Conversely, at the ring stage, PfGCN5 or PfPHD1 domain deletions disrupted the mutually exclusive expression pattern of the entire var gene family, which encodes the virulent factor PfEMP1. Correlation analysis between the chromatin state and alteration of gene expression demonstrated that up- and down-regulated genes in these mutants are highly correlated with the silent and active chromatin states in the wild-type parasite, respectively. Collectively, the PfGCN5 complex represents a novel HAT complex with a unique subunit composition including an AP2 transcription factor, which signifies a new paradigm for targeting the co-activator complex to regulate general and parasite-specific cellular processes in this low-branching parasitic protist.


Assuntos
Eritrócitos/parasitologia , Histona Acetiltransferases/metabolismo , Prolina Dioxigenases do Fator Induzível por Hipóxia/metabolismo , Malária Falciparum/parasitologia , Plasmodium falciparum/fisiologia , Domínios e Motivos de Interação entre Proteínas , Proteínas de Protozoários/metabolismo , Acetilação , Cromatina/genética , Cromatina/metabolismo , Eritrócitos/metabolismo , Regulação da Expressão Gênica , Histona Acetiltransferases/genética , Humanos , Prolina Dioxigenases do Fator Induzível por Hipóxia/genética , Malária Falciparum/metabolismo , Proteínas de Protozoários/genética , Virulência
11.
Nat Commun ; 12(1): 4563, 2021 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-34315897

RESUMO

The emergence and spread of Plasmodium falciparum parasites resistant to front-line antimalarial artemisinin-combination therapies (ACT) threatens to erase the considerable gains against the disease of the last decade. Here, we develop a large-scale phenotypic screening pipeline and use it to carry out a large-scale forward-genetic phenotype screen in P. falciparum to identify genes allowing parasites to survive febrile temperatures. Screening identifies more than 200 P. falciparum mutants with differential responses to increased temperature. These mutants are more likely to be sensitive to artemisinin derivatives as well as to heightened oxidative stress. Major processes critical for P. falciparum tolerance to febrile temperatures and artemisinin include highly essential, conserved pathways associated with protein-folding, heat shock and proteasome-mediated degradation, and unexpectedly, isoprenoid biosynthesis, which originated from the ancestral genome of the parasite's algal endosymbiont-derived plastid, the apicoplast. Apicoplast-targeted genes in general are upregulated in response to heat shock, as are other Plasmodium genes with orthologs in plant and algal genomes. Plasmodium falciparum parasites appear to exploit their innate febrile-response mechanisms to mediate resistance to artemisinin. Both responses depend on endosymbiont-derived genes in the parasite's genome, suggesting a link to the evolutionary origins of Plasmodium parasites in free-living ancestors.


Assuntos
Apicoplastos/metabolismo , Artemisininas/farmacologia , Resistência a Medicamentos , Febre/parasitologia , Malária Falciparum/parasitologia , Parasitos/fisiologia , Animais , Apicoplastos/efeitos dos fármacos , Resistência a Medicamentos/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Resposta ao Choque Térmico/efeitos dos fármacos , Mutação/genética , Parasitos/efeitos dos fármacos , Fenótipo , Plasmodium falciparum/genética , Transdução de Sinais/efeitos dos fármacos , Temperatura , Terpenos/metabolismo , Transcrição Gênica/efeitos dos fármacos , Resposta a Proteínas não Dobradas/efeitos dos fármacos
12.
J Genet Genomics ; 47(9): 513-521, 2020 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-33272860

RESUMO

The human malaria parasite Plasmodium falciparum thrives in radically different host environments in mosquitoes and humans, with only a limited set of transcription factors. The nature of regulatory elements or their target genes in the P. falciparum genome remains elusive. Here, we found that this eukaryotic parasite uses an efficient way to maximally use genetic and epigenetic regulation to form regulatory units (RUs) during blood infections. Genes located in the same RU tend to have the same pattern of expression over time and are associated with open chromatin along regulatory elements. To precisely define and quantify these RUs, a novel hidden Markov model was developed to capture the regulatory structure in a genome-wide fashion by integrating expression and epigenetic evidence. We successfully identified thousands of RUs and cross-validated with previous findings. We found more genes involved in red blood cell (RBC) invasion located in the same RU as the PfAP2-I (AP2-I) transcription factor, demonstrating that AP2-I is responsible for regulating RBC invasion. Our study has provided a regulatory mechanism for a compact eukaryotic genome and offers new insights into the in vivo transcriptional regulation of the P. falciparum intraerythrocytic stage.


Assuntos
Regulação da Expressão Gênica/genética , Malária Falciparum/genética , Plasmodium falciparum/genética , Sequências Reguladoras de Ácido Nucleico/genética , Cromatina/genética , Cromossomos/genética , Epigênese Genética/genética , Eritrócitos , Genoma Humano , Humanos , Malária Falciparum/parasitologia , Malária Falciparum/patologia , Plasmodium falciparum/patogenicidade
13.
J Pers Med ; 10(4)2020 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33113957

RESUMO

We have entered an era of direct-to-consumer (DTC) genomics. Patients have relayed many success stories of DTC genomics about finding causal mutations of genetic diseases before showing any symptoms and taking precautions. However, consumers may also take unnecessary medical actions based on false alarms of "pathogenic alleles". The severity of this problem is not well known. Using publicly available data, we compared DTC microarray genotyping data with deep-sequencing data of 5 individuals and manually checked each inconsistently reported single nucleotide variants (SNVs). We estimated that, on average, a person would have ~5 "pathogenic" alleles reported due to wrongly reported genotypes if using a 23andMe genotyping microarray. We also found that the number of wrongly classified "pathogenic" alleles per person is at least as significant as those due to wrongly reported genotypes. We show that the scale of the false alarm problem could be large enough that the medical costs will become a burden to public health.

14.
Lab Chip ; 20(6): 1124-1139, 2020 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-32055808

RESUMO

Advanced cell culture methods for modeling organ-level structure have been demonstrated to replicate in vivo conditions more accurately than traditional in vitro cell culture. Given that the liver is particularly important to human health, several advanced culture methods have been developed to experiment with liver disease states, including infection with Plasmodium parasites, the causative agent of malaria. These models have demonstrated that intrahepatic parasites require functionally stable hepatocytes to thrive and robust characterization of the parasite populations' response to investigational therapies is dependent on high-content and high-resolution imaging (HC/RI). We previously reported abiotic confinement extends the functional longevity of primary hepatocytes in a microfluidic platform and set out to instill confinement in a microtiter plate platform while maintaining optical accessibility for HC/RI; with an end-goal of producing an improved P. vivax liver stage culture model. We developed a novel fabrication process in which a PDMS soft mold embosses hepatocyte-confining microfeatures into polystyrene, resulting in microfeature-based hepatocyte confinement (µHEP) slides and plates. Our process was optimized to form both microfeatures and culture wells in a single embossing step, resulting in a 100 µm-thick bottom ideal for HC/RI, and was found inexpensively amendable to microfeature design changes. Microfeatures improved intrahepatic parasite infection rates and µHEP systems were used to reconfirm the activity of reference antimalarials in phenotypic dose-response assays. RNAseq of hepatocytes in µHEP systems demonstrated microfeatures sustain hepatic differentiation and function, suggesting broader utility for preclinical hepatic assays; while our tailorable embossing process could be repurposed for developing additional organ models.


Assuntos
Antimaláricos , Malária , Antimaláricos/farmacologia , Técnicas de Cultura de Células , Hepatócitos , Humanos , Fígado
15.
mSphere ; 5(1)2020 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-31915223

RESUMO

Protein kinases are important mediators of signal transduction in cellular pathways, and calcium-dependent protein kinases (CDPKs) compose a unique class of calcium-dependent kinases present in plants and apicomplexans, including Plasmodium parasites, the causative agents of malaria. During the asexual stage of infection, the human malaria parasite Plasmodium falciparum grows inside red blood cells, and P. falciparum calcium-dependent protein kinase 5 (PfCDPK5) is required for egress from the host cell. In this paper, we characterize the late-schizont-stage P. falciparum phosphoproteome by performing large-scale phosphoproteomic profiling on tightly synchronized parasites just prior to egress, identifying 2,704 phosphorylation sites on 919 proteins. Using a conditional knockdown of PfCDPK5, we identify 58 phosphorylation sites on 50 proteins with significant reduction in levels of PfCDPK5-deficient parasites. Furthermore, gene ontology analysis of the identified proteins reveals enrichment in transmembrane- and membrane-associated proteins and in proteins associated with transport activity. Among the identified proteins is PfNPT1, a member of the apicomplexan-specific novel putative transporter (NPT) family of proteins. We show that PfNPT1 is a potential substrate of PfCDPK5 and that PfNPT1 localizes to the parasite plasma membrane. Importantly, P. falciparum egress relies on many proteins unique to Apicomplexa that are therefore attractive targets for antimalarial therapeutics.IMPORTANCE The malaria parasite Plasmodium falciparum is a major cause of morbidity and mortality globally. The P. falciparum parasite proliferates inside red blood cells during the blood stage of infection, and egress from the red blood cell is critical for parasite survival. P. falciparum calcium-dependent protein kinase 5 (PfCDPK5) is essential for egress; parasites deficient in PfCDPK5 remain trapped inside their host cells. We have used a label-free quantitative mass spectrometry approach to identify the phosphoproteome of schizont-stage parasites just prior to egress and identify 50 proteins that display a significant reduction in phosphorylation in PfCDPK5-deficient parasites. We show that a member of the Apicomplexan-specific transport protein family, PfNPT1 is a potential substrate of PfCDPK5 and is localized to the parasite plasma membrane. P. falciparum egress requires several proteins not present in human cells, thus making this pathway an ideal target for new therapeutics.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Fosfoproteínas/análise , Plasmodium falciparum/enzimologia , Plasmodium falciparum/genética , Proteínas Quinases/metabolismo , Proteoma/metabolismo , Proteínas de Protozoários/metabolismo , Proteínas de Ligação ao Cálcio/genética , Membrana Celular/metabolismo , Ontologia Genética , Fosforilação , Proteínas Quinases/genética , Proteínas de Protozoários/genética , Esquizontes/genética , Esquizontes/metabolismo , Transdução de Sinais
16.
F1000Res ; 8: 1135, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31824661

RESUMO

Background: Basic and clinical scientific research at the University of South Florida (USF) have intersected to support a multi-faceted approach around a common focus on rare iron-related diseases. We proposed a modified version of the National Center for Biotechnology Information's (NCBI) Hackathon-model to take full advantage of local expertise in building "Iron Hack", a rare disease-focused hackathon. As the collaborative, problem-solving nature of hackathons tends to attract participants of highly-diverse backgrounds, organizers facilitated a symposium on rare iron-related diseases, specifically porphyrias and Friedreich's ataxia, pitched at general audiences. Methods: The hackathon was structured to begin each day with presentations by expert clinicians, genetic counselors, researchers focused on molecular and cellular biology, public health/global health, genetics/genomics, computational biology, bioinformatics, biomolecular science, bioengineering, and computer science, as well as guest speakers from the American Porphyria Foundation (APF) and Friedreich's Ataxia Research Alliance (FARA) to inform participants as to the human impact of these diseases. Results: As a result of this hackathon, we developed resources that are relevant not only to these specific disease-models, but also to other rare diseases and general bioinformatics problems. Within two and a half days, "Iron Hack" participants successfully built collaborative projects to visualize data, build databases, improve rare disease diagnosis, and study rare-disease inheritance. Conclusions: The purpose of this manuscript is to demonstrate the utility of a hackathon model to generate prototypes of generalizable tools for a given disease and train clinicians and data scientists to interact more effectively.


Assuntos
Ataxia de Friedreich , Porfirias , Bases de Dados Factuais , Humanos , Ferro , Doenças Raras , Estados Unidos
17.
BMC Syst Biol ; 13(1): 5, 2019 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-30634978

RESUMO

BACKGROUND: The lack of a continuous long-term in vitro culture system for Plasmodium vivax severely limits our knowledge of pathophysiology of the most widespread malaria parasite. To gain direct understanding of P. vivax human infections, we used Next Generation Sequencing data mining to unravel parasite in vivo expression profiles for P. vivax, and P. falciparum as comparison. RESULTS: We performed cloud and local computing to extract parasite transcriptomes from publicly available raw data of human blood samples. We developed a Poisson Modelling (PM) method to confidently identify parasite derived transcripts in mixed RNAseq signals of infected host tissues. We successfully retrieved and reconstructed parasite transcriptomes from infected patient blood as early as the first blood stage cycle; and the same methodology did not recover any significant signal from controls. Surprisingly, these first generation blood parasites already show strong signature of transmission, which indicates the commitment from asexual-to-sexual stages. Further, we place the results within the context of P. vivax's complex life cycle, by developing mathematical models for P. vivax and P. falciparum and using sensitivity analysis assess the relative epidemiological impact of possible early stage transmission. CONCLUSION: The study uncovers the earliest onset of P. vivax blood pathogenesis and highlights the challenges of P. vivax eradication programs.


Assuntos
Malária Vivax/transmissão , Plasmodium vivax/fisiologia , Sangue/parasitologia , Gametogênese , Perfilação da Expressão Gênica , Humanos , Malária Vivax/epidemiologia , Modelos Biológicos , Plasmodium vivax/genética , RNA Mensageiro/genética
18.
BMC Genomics ; 19(1): 849, 2018 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-30486796

RESUMO

BACKGROUND: Plasmodium falciparum exhibits resistance to the artemisinin component of the frontline antimalarial treatment Artemisinin-based Combination Therapy in South East Asia. Millions of lives will be at risk if artemisinin resistance (ART-R) spreads to Africa. Single non-synonymous mutations in the propeller region of PF3D7_1343700,"K13" are implicated in resistance. In this work, we use transcriptional profiling to characterize a laboratory-generated k13 insertional mutant previously demonstrated to have increased sensitivity to artemisinins to explore the functional role of k13. RESULTS: A set of RNA-seq and microarray experiments confirmed that the expression profile of k13 is specifically altered during the early ring and early trophozoite stages of the mutant intraerythrocytic development cycle. The down-regulation of k13 transcripts in this mutant during the early ring stage is associated with a transcriptome advance towards a more trophozoite-like state. To discover the specific downstream effect of k13 dysregulation, we developed a new computational method to search for differential gene expression while accounting for the temporal sequence of transcription. We found that the strongest biological signature of the transcriptome shift is an up-regulation of DNA replication and repair genes during the early ring developmental stage and a down-regulation of DNA replication and repair genes during the early trophozoite stage; by contrast, the expressions of housekeeping genes are unchanged. This effect, due to k13 dysregulation, is antagonistic, such that k13 levels are negatively correlated with DNA replication and repair gene expression. CONCLUSION: Our results support a role for k13 as a stress response regulator consistent with the hypothesis that artemisinins mode of action is oxidative stress and k13 as a functional homolog of Keap1 which in humans regulates DNA replication and repair genes in response to oxidative stress.


Assuntos
Reparo do DNA/genética , Replicação do DNA/genética , Regulação da Expressão Gênica , Genes de Protozoários , Plasmodium falciparum/genética , Algoritmos , Elementos de DNA Transponíveis/genética , Perfilação da Expressão Gênica , Humanos , Modelos Biológicos , Mutação/genética , Reprodutibilidade dos Testes , Transcriptoma/genética
19.
Sci Rep ; 8(1): 12183, 2018 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-30111801

RESUMO

Malaria parasites transmitted by mosquito bite are remarkably efficient in establishing human infections. The infection process requires roughly 30 minutes and is highly complex as quiescent sporozoites injected with mosquito saliva must be rapidly activated in the skin, migrate through the body, and infect the liver. This process is poorly understood for Plasmodium vivax due to low infectivity in the in vitro models. To study this skin-to-liver-stage of malaria, we used quantitative bioassays coupled with transcriptomics to evaluate parasite changes linked with mammalian microenvironmental factors. Our in vitro phenotyping and RNA-seq analyses revealed key microenvironmental relationships with distinct biological functions. Most notable, preservation of sporozoite quiescence by exposure to insect-like factors coupled with strategic activation limits untimely activation of invasion-associated genes to dramatically increase hepatocyte invasion rates. We also report the first transcriptomic analysis of the P. vivax sporozoite interaction in salivary glands identifying 118 infection-related differentially-regulated Anopheles dirus genes. These results provide important new insights in malaria parasite biology and identify priority targets for antimalarial therapeutic interventions to block P. vivax infection.


Assuntos
Plasmodium vivax/genética , Plasmodium vivax/fisiologia , Esporozoítos/genética , Animais , Anopheles/parasitologia , Perfilação da Expressão Gênica , Interações Hospedeiro-Patógeno/genética , Humanos , Insetos Vetores/parasitologia , Malária/parasitologia , Malária Vivax/parasitologia , Mosquitos Vetores/genética , Parasitos , Plasmodium vivax/patogenicidade , Glândulas Salivares/parasitologia , Esporozoítos/patogenicidade , Esporozoítos/fisiologia
20.
Blood Cells Mol Dis ; 72: 22-33, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30007855

RESUMO

Progress towards an in-depth understanding of the final steps of the erythroid lineage development is paramount for many hematological diseases. We have characterized the final stages of reticulocyte maturation from bone marrow to peripheral blood using for the first time single-cell Mass Cytometry (CyTOF). We were able to measure the expression of 31 surface markers within a single red blood cell (RBC). We demonstrate the validity of CyTOF for RBC phenotyping by confirming the progressive reduction of transferrin receptor 1 (CD71) during reticulocyte maturation to mature RBC. We highlight the high-dimensional nature of mass cytometry data by correlating the expression of multiple proteins on individual RBCs. We further describe a more drastic reduction pattern for a component of the alpha4/beta1 integrin CD49d at the very early steps of reticulocyte maturation in bone marrow and directly linked with the mitochondria remnants clearance pattern. The enhanced and accurate RBC phenotyping potential of CyTOF described herein could be beneficial to decipher RBC preferences, as well as still not well understood receptor-ligand interaction of some hemotropic parasites such as the malaria causing agent Plasmodium vivax.


Assuntos
Técnicas Citológicas/instrumentação , Eritrócitos/metabolismo , Análise de Célula Única/métodos , Animais , Antígenos CD/análise , Biomarcadores/análise , Diferenciação Celular , Linhagem da Célula , Técnicas Citológicas/métodos , Eritrócitos/fisiologia , Humanos , Imunofenotipagem , Integrina alfa4/análise , Receptores da Transferrina/análise , Reticulócitos/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...