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1.
Mol Microbiol ; 120(5): 723-739, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37800599

RESUMO

DectiSomes are anti-infective drug-loaded liposomes targeted to pathogenic cells by pathogen receptors including the Dectins. We have previously used C-type lectin (CTL) pathogen receptors Dectin-1, Dectin-2, and DC-SIGN to target DectiSomes to the extracellular oligoglycans surrounding diverse pathogenic fungi and kill them. Dectin-3 (also known as MCL, CLEC4D) is a CTL pathogen receptor whose known cognate ligands are partly distinct from other CTLs. We expressed and purified a truncated Dectin-3 polypeptide (DEC3) comprised of its carbohydrate recognition domain and stalk region. We prepared amphotericin B (AmB)-loaded pegylated liposomes (AmB-LLs) and coated them with this isoform of Dectin-3 (DEC3-AmB-LLs), and we prepared control liposomes coated with bovine serum albumin (BSA-AmB-LLs). DEC3-AmB-LLs bound to the exopolysaccharide matrices of Candida albicans, Rhizopus delemar (formerly known as R. oryzae), and Cryptococcus neoformans from one to several orders of magnitude more strongly than untargeted AmB-LLs or BSA-AmB-LLs. The data from our quantitative fluorescent binding assays were standardized using a CellProfiler program, AreaPipe, that was developed for this purpose. Consistent with enhanced binding, DEC3-AmB-LLs inhibited and/or killed C. albicans and R. delemar more efficiently than control liposomes and significantly reduced the effective dose of AmB. In conclusion, Dectin-3 targeting has the potential to advance our goal of building pan-antifungal DectiSomes.


Assuntos
Antifúngicos , Criptococose , Humanos , Antifúngicos/farmacologia , Lipossomos/química , Lipossomos/farmacologia , Anfotericina B/farmacologia , Anfotericina B/química , Candida albicans
2.
PLoS Pathog ; 17(7): e1009699, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34293050

RESUMO

Globally, there are several million individuals with life-threatening invasive fungal diseases such as candidiasis, aspergillosis, cryptococcosis, Pneumocystis pneumonia (PCP), and mucormycosis. The mortality rate for these diseases generally exceeds 40%. Annual medical costs to treat these invasive fungal diseases in the United States exceed several billion dollars. In addition to AIDS patients, the risks of invasive mycoses are increasingly found in immune-impaired individuals or in immunosuppressed patients following stem cell or organ transplant or implantation of medical devices. Current antifungal drug therapies are not meeting the challenge, because (1) at safe doses, they do not provide sufficient fungal clearance to prevent reemergence of infection; (2) most become toxic with extended use; (3) drug-resistant fungal isolates are emerging; and (4) only one new class of antifungal drugs has been approved for clinical use in the last 2 decades. DectiSomes represent a novel design of drug delivery to drastically increase drug efficacy. Antifungals packaged in liposomes are targeted specifically to where the pathogen is, through binding to the fungal cell walls or exopolysaccharide matrices using the carbohydrate recognition domains of pathogen receptors. Relative to untargeted liposomal drug, DectiSomes show order of magnitude increases in the binding to and killing of Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus in vitro and similarly improved efficacy in mouse models of pulmonary aspergillosis. DectiSomes have the potential to usher in a new antifungal drug treatment paradigm.


Assuntos
Antifúngicos/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Micoses/tratamento farmacológico , Animais , Portadores de Fármacos/administração & dosagem , Humanos , Lectinas Tipo C/metabolismo , Lipossomos , Camundongos
3.
Antimicrob Agents Chemother ; 66(1): e0146721, 2022 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-34633846

RESUMO

Candida albicans causes life-threatening disseminated candidiasis. Individuals at greatest risk have weakened immune systems. An outer cell wall, exopolysaccharide matrix, and biofilm rich in oligoglucans and oligomannans help Candida spp. evade host defenses. Even after antifungal treatment, the 1-year mortality rate exceeds 25%. Undoubtedly, there is room to improve drug performance. The mammalian C-type lectin pathogen receptors Dectin-1 and Dectin-2 bind to fungal oligoglucans and oligomannans, respectively. We previously coated amphotericin B-loaded liposomes, AmB-LLs, pegylated analogs of AmBisome, with the ligand binding domains of these two Dectins. DectiSomes, DEC1-AmB-LLs and DEC2-AmB-LLs, showed two distinct patterns of binding to the exopolysaccharide matrix surrounding C. albicans hyphae grown in vitro. Here we showed that DectiSomes were preferentially associated with fungal colonies in the kidneys. In a neutropenic mouse model of candidiasis, DEC1-AmB-LLs and DEC2-AmB-LLs delivering only one dose of 0.2 mg/kg AmB reduced the kidney fungal burden several fold relative to AmB-LLs. DEC1-AmB-LLs and DEC2-AmB-LLs increased the percent of surviving mice 2.5-fold and 8.3-fold, respectively, relative to AmB-LLs. Dectin-2 targeting of anidulafungin loaded liposomes, DEC2-AFG-LLs, and of commercial AmBisome, DEC2-AmBisome, reduced fungal burden in the kidneys several fold over their untargeted counterparts. The data herein suggest that targeting of a variety of antifungal drugs to fungal glycans may achieve lower safer effective doses and improve drug efficacy against a variety of invasive fungal infections.


Assuntos
Candidíase , Lipossomos , Animais , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Candida albicans , Candidíase/microbiologia , Lipossomos/química , Mamíferos , Camundongos , Polissacarídeos/farmacologia
4.
Sleep Breath ; 25(3): 1641-1653, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33037528

RESUMO

PURPOSE: Obstructive sleep apnea (OSA) results in systemic intermittent hypoxia. By one model, hypoxic stress signaling in OSA patients alters the levels of inflammatory soluble cytokines TNF and IL6, damages the blood brain barrier, and activates microglial targeting of neuronal cell death to increase the risk of neurodegenerative disorders and other diseases. However, it is not yet clear if OSA significantly alters the levels of the soluble isoforms of TNF receptors TNFR1 and TNFR2 and IL6 receptor (IL6R) and co-receptor gp130, which have the potential to modulate TNF and IL6 signaling. METHODS: Picogram per milliliter levels of the soluble isoforms of these four cytokine receptors were estimated in OSA patients, in OSA patients receiving airways therapy, and in healthy control subjects. Triplicate samples were examined using Bio-Plex fluorescent bead microfluidic technology. The statistical significance of cytokine data was estimated using the nonparametric Wilcoxon rank-sum test. The clustering of these high-dimensional data was visualized using t-distributed stochastic neighbor embedding (t-SNE). RESULTS: OSA patients had significant twofold to sevenfold reductions in the soluble serum isoforms of all four cytokine receptors, gp130, IL6R, TNFR1, and TNFR2, as compared with control individuals (p = 1.8 × 10-13 to 4 × 10-8). Relative to untreated OSA patients, airways therapy of OSA patients had significantly higher levels of gp130 (p = 2.8 × 10-13), IL6R (p = 1.1 × 10-9), TNFR1 (p = 2.5 × 10-10), and TNFR2 (p = 5.7 × 10-9), levels indistinguishable from controls (p = 0.29 to 0.95). The data for most airway-treated patients clustered with healthy controls, but the data for a few airway-treated patients clustered with apneic patients. CONCLUSIONS: Patients with OSA have aberrantly low levels of four soluble cytokine receptors associated with neurodegenerative disease, gp130, IL6R, TNFR1, and TNFR2. Most OSA patients receiving airways therapy have receptor levels indistinguishable from healthy controls, suggesting a chronic intermittent hypoxia may be one of the factors contributing to low receptor levels in untreated OSA patients.


Assuntos
Pressão Positiva Contínua nas Vias Aéreas , Doenças Neurodegenerativas/epidemiologia , Receptores de Citocinas/sangue , Apneia Obstrutiva do Sono/terapia , Adulto , Idoso , Receptor gp130 de Citocina/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Receptores de Interleucina-6/sangue , Receptores Tipo I de Fatores de Necrose Tumoral/sangue , Receptores Tipo II do Fator de Necrose Tumoral/sangue , Apneia Obstrutiva do Sono/sangue , Resultado do Tratamento
5.
Clin Immunol ; 221: 108601, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33017651

RESUMO

Obstructive Sleep Apnea (OSA) damages the health of 35% of adult Americans. Disordered sleep results in increased risk of several autoimmune disorders, but the molecular links to autoimmunity are poorly understood. Herein, we identified four cytokines associated with autoimmune disease, whose median serum levels were significantly different for OSA patients receiving airways therapy, from the levels in untreated OSA patients, APRIL (5.2-fold lower, p = 3.5 × 10-11), CD30 (1.6-fold higher, p = 7.7 × 10-5), IFN-Alpha-2 (2.9-fold higher, p = 9.6 × 10-14) and IL-2 (1.9-fold higher, p = 0.0003). Cytokine levels in airways treated patients were similar to the levels in control subjects. t-SNE and UMAP analysis of these high dimensional patient cytokine data identified only two groups, suggesting a similar global response for all four cytokines to airways therapy. Our findings suggest the levels of these four cytokines may be altered by disordered sleep and perhaps by chronic hypoxia. Therapeutic options are discussed.


Assuntos
Doenças Autoimunes/terapia , Pressão Positiva Contínua nas Vias Aéreas , Citocinas/imunologia , Apneia Obstrutiva do Sono/terapia , Adulto , Idoso , Doenças Autoimunes/sangue , Doenças Autoimunes/imunologia , Citocinas/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Apneia Obstrutiva do Sono/sangue , Apneia Obstrutiva do Sono/imunologia
6.
Plant J ; 94(2): 215-231, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29513366

RESUMO

Cell differentiation is driven by changes in the activity of transcription factors (TFs) and subsequent alterations in transcription. To study this process, differences in TF binding between cell types can be deduced by probing chromatin accessibility. We used cell type-specific nuclear purification followed by the assay for transposase-accessible chromatin (ATAC-seq) to delineate differences in chromatin accessibility and TF regulatory networks between stem cells of the shoot apical meristem (SAM) and differentiated leaf mesophyll cells in Arabidopsis thaliana. Chromatin accessibility profiles of SAM stem cells and leaf mesophyll cells were very similar at a qualitative level, yet thousands of regions having quantitatively different chromatin accessibility were also identified. Analysis of the genomic regions preferentially accessible in each cell type identified hundreds of overrepresented TF-binding motifs, highlighting sets of TFs that are probably important for each cell type. Within these sets, we found evidence for extensive co-regulation of target genes by multiple TFs that are preferentially expressed in each cell type. Interestingly, the TFs within each of these cell type-enriched sets also showed evidence of extensively co-regulating each other. We further found that preferentially accessible chromatin regions in mesophyll cells tended to also be substantially accessible in the stem cells, whereas the converse was not true. This observation suggests that the generally higher accessibility of regulatory elements in stem cells might contribute to their developmental plasticity. This work demonstrates the utility of cell type-specific chromatin accessibility profiling for the rapid development of testable models of regulatory control differences between cell types.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/metabolismo , Cromatina/metabolismo , Células do Mesofilo/metabolismo , Células-Tronco/metabolismo , Fatores de Transcrição/fisiologia , Arabidopsis/citologia , Regulação da Expressão Gênica de Plantas , Meristema/citologia , Meristema/metabolismo , Folhas de Planta/citologia , Folhas de Planta/metabolismo , Brotos de Planta/citologia , Brotos de Planta/metabolismo
7.
Int J Vitam Nutr Res ; 87(5-6): 271-278, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30499755

RESUMO

Folate, a water-soluble vitamin, is a key source of one-carbon groups for DNA methylation, but studies of the DNA methylation response to supplemental folic acid yield inconsistent results. These studies are commonly conducted using whole blood, which contains a mixed population of white blood cells that have been shown to confound results. The objective of this study was to determine if CD16+ neutrophils may provide more specific data than whole blood for identifying DNA methylation response to chronic folic acid supplementation. The study was performed in normal weight (BMI 18.5 - 24.9 kg/m2) women (18 - 35 y; n = 12), with blood samples taken before and after 8 weeks of folic acid supplementation at 800 µg/day. DNA methylation patterns from whole blood and isolated CD16+ neutrophils were measured across >485,000 CpG sites throughout the genome using the Infinium HumanMethylation450 BeadChip. Over the course of the 8-week supplementation, 6746 and 7513 CpG sites changed (p < 0.05) in whole blood and CD16+ neutrophils, respectively. DNA methylation decreased in 68.4% (whole blood) and 71.8% (CD16+ neutrophils) of these sites. There were only 182 CpG sites that changed in both the whole blood and CD16+ neutrophils, 139 of which changed in the same direction. These results suggest that the genome-wide DNA methylation response to chronic folic acid supplementation is different between whole blood and CD16+ neutrophils and that a single white blood cell type may function as a more specific epigenetic reporter of folate status than whole blood.

8.
BMC Plant Biol ; 15: 177, 2015 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-26160044

RESUMO

BACKGROUND: The actin cytoskeleton is involved in an array of integral structural and developmental processes throughout the cell. One of actin's best-studied binding partners is the small ubiquitously expressed protein, profilin. Arabidopsis thaliana is known to encode a family of five profilin sequence variants: three vegetative (also constitutive) profilins that are predominantly expressed in all vegetative tissues and ovules, and two reproductive profilins that are specifically expressed in pollen. This paper analyzes the roles of the three vegetative profilin members, PRF1, PRF2, and PRF3, in plant cell and organ development. RESULTS: Using a collection of knockout or severe knockdown T-DNA single mutants, we found that defects in each of the three variants gave rise to specific developmental deficiencies. Plants lacking PRF1 or PRF2 had defects in rosette leaf morphology and inflorescence stature, while those lacking PRF3 led to plants with slightly elongated petioles. To further examine these effects, double mutants and double and triple gene-silenced RNAi epialleles were created. These plants displayed significantly compounded developmental defects, as well as distinct lateral root growth morphological phenotypes. CONCLUSION: These results suggest that having at least one vegetative profilin gene is essential to viability. Evidence is presented that combinations of independent function, quantitative genetic effects, and functional redundancy have preserved the three vegetative profilin genes in the Arabidopsis lineage.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/genética , DNA Bacteriano/genética , DNA de Plantas/genética , Organogênese Vegetal , Arabidopsis/citologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , DNA Bacteriano/metabolismo , DNA de Plantas/metabolismo , Técnicas de Silenciamento de Genes , Mutação , Fenótipo , Profilinas/genética , Profilinas/metabolismo , Interferência de RNA
9.
BMC Neurosci ; 16: 51, 2015 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-26260473

RESUMO

BACKGROUND: Recent evidence identifies the hippocampus, a brain structure commonly associated with learning and memory, as key to the regulation of food intake and the development and consequences of obesity. Intake of a high fat diet (HFD) results in altered consumptive behavior, hippocampal damage, and cognitive deficits. While many studies report the effects of HFD after chronic consumption and in the instance of obesity, few examine the events that occur following acute HFD consumption. In this study, male rats were fed either a control diet (10% fat by kcal) or HFD (45% fat by kcal) for 72 h. At the end of the 72-h period, serum and tissues were collected and weighed. Brains were rapidly frozen or formalin-fixed in preparation for qRT-PCR or immunohistochemistry, respectively. RESULTS: Acute intake of HFD resulted in higher serum levels of leptin and cholesterol, with no significant changes in final body weight or adipose tissue mass. In the dorsal hippocampus, transcription of the neuroprotective peptide galanin was significantly upregulated along with a trend for an increase in brain-derived neurotrophic factor and histone deacetylase 2 in the rats fed HFD. In the ventral hippocampus, there was a significant increase in histone deacetylase 4 and a decrease in galanin receptor 1 in this group. Results from immunohistochemistry validate strong presence of the galanin peptide in the CA1/CA2 region of the dorsal hippocampus. CONCLUSIONS: These results provide evidence for a distinct response in specific functional regions of the hippocampus following acute HFD intake.


Assuntos
Dieta Hiperlipídica/efeitos adversos , Galanina/metabolismo , Hipocampo/metabolismo , Tecido Adiposo/patologia , Tecido Adiposo/fisiologia , Animais , Peso Corporal/fisiologia , Colesterol/sangue , Ingestão de Alimentos/fisiologia , Ensaio de Imunoadsorção Enzimática , Expressão Gênica , Imuno-Histoquímica , Leptina/sangue , Masculino , Tamanho do Órgão , Ratos Long-Evans , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Tempo
10.
Plant Cell ; 24(5): 2041-57, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22589468

RESUMO

Actin is an essential multifunctional protein encoded by two distinct ancient classes of genes in animals (cytoplasmic and muscle) and plants (vegetative and reproductive). The prevailing view is that each class of actin variants is functionally distinct. However, we propose that the vegetative plant and cytoplasmic animal variants have conserved functional competence for spatial development inherited from an ancestral protist actin sequence. To test this idea, we ectopically expressed animal and protist actins in Arabidopsis thaliana double vegetative actin mutants that are dramatically altered in cell and organ morphologies. We found that expression of cytoplasmic actins from humans and even a highly divergent invertebrate Ciona intestinalis qualitatively and quantitatively suppressed the root cell polarity and organ defects of act8 act7 mutants and moderately suppressed the root-hairless phenotype of act2 act8 mutants. By contrast, human muscle actins were unable to support prominently any aspect of plant development. Furthermore, actins from three protists representing Choanozoa, Archamoeba, and green algae efficiently suppressed all the phenotypes of both the plant mutants. Remarkably, these data imply that actin's competence to carry out a complex suite of processes essential for multicellular development was already fully developed in single-celled protists and evolved nonprogressively from protists to plants and animals.


Assuntos
Proteínas de Arabidopsis/classificação , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Animais , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Archamoebae/genética , Archamoebae/metabolismo , Clorófitas/genética , Clorófitas/metabolismo , Coanoflagelados/genética , Coanoflagelados/metabolismo , Ciona intestinalis/genética , Ciona intestinalis/metabolismo , Filogenia
11.
Plant Cell ; 23(10): 3711-26, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22010035

RESUMO

Actin filament arrays are constantly remodeled as the needs of cells change as well as during responses to biotic and abiotic stimuli. Previous studies demonstrate that many single actin filaments in the cortical array of living Arabidopsis thaliana epidermal cells undergo stochastic dynamics, a combination of rapid growth balanced by disassembly from prolific severing activity. Filament turnover and dynamics are well understood from in vitro biochemical analyses and simple reconstituted systems. However, the identification in living cells of the molecular players involved in controlling actin dynamics awaits the use of model systems, especially ones where the power of genetics can be combined with imaging of individual actin filaments at high spatial and temporal resolution. Here, we test the hypothesis that actin depolymerizing factor (ADF)/cofilin contributes to stochastic filament severing and facilitates actin turnover. A knockout mutant for Arabidopsis ADF4 has longer hypocotyls and epidermal cells when compared with wild-type seedlings. This correlates with a change in actin filament architecture; cytoskeletal arrays in adf4 cells are significantly more bundled and less dense than in wild-type cells. Several parameters of single actin filament turnover are also altered. Notably, adf4 mutant cells have a 2.5-fold reduced severing frequency as well as significantly increased actin filament lengths and lifetimes. Thus, we provide evidence that ADF4 contributes to the stochastic dynamic turnover of actin filaments in plant cells.


Assuntos
Citoesqueleto de Actina/metabolismo , Fatores de Despolimerização de Actina/metabolismo , Actinas/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Citoesqueleto de Actina/ultraestrutura , Fatores de Despolimerização de Actina/genética , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/ultraestrutura , Proteínas de Arabidopsis/genética , Expressão Gênica , Técnicas de Inativação de Genes , Hipocótilo/genética , Hipocótilo/crescimento & desenvolvimento , Hipocótilo/metabolismo , Hipocótilo/ultraestrutura , Família Multigênica , Mutação , Fenótipo , Epiderme Vegetal/genética , Epiderme Vegetal/crescimento & desenvolvimento , Epiderme Vegetal/metabolismo , Epiderme Vegetal/ultraestrutura , Plantas Geneticamente Modificadas , Proteínas Recombinantes , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Plântula/ultraestrutura , Processos Estocásticos , Fatores de Tempo
12.
Nucleic Acids Res ; 40(20): e156, 2012 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-22821568

RESUMO

RNAsnap™ is a simple and novel method that recovers all intracellular RNA quantitatively (>99%), faster (<15 min) and less expensively (∼3 cents/sample) than any of the currently available RNA isolation methods. In fact, none of the bacterial RNA isolation methods, including the commercial kits, are effective in recovering all species of intracellular RNAs (76-5700 nt) with equal efficiency, which can lead to biased results in genome-wide studies involving microarray or RNAseq analysis. The RNAsnap™ procedure yields ∼60 µg of RNA from 10(8) Escherichia coli cells that can be used directly for northern analysis without any further purification. Based on a comparative analysis of specific transcripts ranging in size from 76 to 5700 nt, the RNAsnap™ method provided the most accurate measure of the relative amounts of the various intracellular RNAs. Furthermore, the RNAsnap™ RNA was successfully used in enzymatic reactions such as RNA ligation, reverse transcription, primer extension and reverse transcriptase-polymerase chain reaction, following sodium acetate/ethanol precipitation. The RNAsnap™ method can be used to isolate RNA from a wide range of Gram-negative and Gram-positive bacteria as well as yeast.


Assuntos
RNA Bacteriano/isolamento & purificação , Técnicas Genéticas , Bactérias Gram-Negativas/genética , Bactérias Gram-Positivas/genética , RNA Bacteriano/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Leveduras/genética
13.
Plant Cell ; 22(6): 1658-66, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20551346

RESUMO

The epitype of a single gene or entire genome is determined by cis-linked differences in chromatin structure. I explore the hypothesis that "epitype and associated phenotypes evolve by gene duplication, divergence, and subfunctionalization" parallel to models for the evolution of genotype. This hypothesis is dissected by considering the relationship between epigenetic control and phenotype, the phylogenetic evidence that epitype evolves from ancestral genes following gene duplication, and the possible evolutionary rates of change for different epitypes. Initial supporting arguments for this hypothesis are discussed based on conserved patterns of nucleosome phasing, DNA methylation, and histone variant H2AZ deposition that appear to contribute to the inheritance of epitype in plants and animals. However, patterns of histone modification in recent segmental chromosome duplications are not well conserved. A continued experimental examination of the link between gene phylogeny and epitype and the evolution of epigenetically determined phenotypes is needed to further explore this hypothesis.


Assuntos
Epigênese Genética , Evolução Molecular , Duplicação Gênica , Filogenia , Metilação de DNA , Meio Ambiente , Histonas/metabolismo , Nucleossomos/metabolismo , Fenótipo
14.
Environ Sci Technol ; 47(10): 5327-35, 2013 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-23590825

RESUMO

Zinc (Zn) is an essential micronutrient which affects plant growth and development in deficiency and can be toxic when present in excess. In Arabidopsis thaliana , different families of cation transporters play pivotal roles in Zn homeostasis. In the present study, we evaluated the effects of Zn in its deficiency (0 µM; Zn-) and excess (75 µM; Zn++) on various morphophysiological and molecular traits. Primary root length was reduced in Zn- seedlings, whereas there were significant increases in the number and length of lateral roots under Zn- and Zn++ conditions, respectively. Concentration of various macro- and microelements showed variations under different Zn regimes and notable among them was the reduced level of iron (Fe) in Zn++ seedlings compared to Zn+. Certain members of the ZIP family (ZIP4, ZIP9, and ZIP12) showed significant induction in roots and shoots of the Zn- seedlings. Their suppression under Zn++ condition indicated their transcriptional regulation by Zn and their roles in the maintenance of its homeostasis. Zn-deficiency-mediated induction of HMA2 in roots and shoots suggested its role in effluxing Zn into xylem for long-distance transport. Attenuation in the expression of Fe-responsive FRO2 and IRT1 in Zn- roots and their induction in Zn++ roots provided empirical evidence toward the prevalence of a cross talk between Zn and Fe homeostasis. Variable effects of Zn- and Zn++ on the expression of subset of genes involved in the homeostasis of phosphate (Pi), potassium (K), and sulfur (S) further highlighted the prevalence of cross talk between the sensing and signaling cascades of Zn and macronutrients. Further, the inducibility of ZIP4 and ZIP12 in response to cadmium (cd) treatment could be harnessed by tailoring them in homologous or heterologous plant system for removing pollutant toxic heavy metals from the environment.


Assuntos
Regulação da Expressão Gênica de Plantas , Genes de Plantas , Zinco/química , Cádmio/química
15.
Adv Drug Deliv Rev ; 196: 114776, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36934519

RESUMO

Combatting the ever-increasing threat from invasive fungal pathogens faces numerous fundamental challenges, including constant human exposure to large reservoirs of species in the environment, the increasing population of immunocompromised or immunosuppressed individuals, the unsatisfactory efficacy of current antifungal drugs and their associated toxicity, and the scientific and economic barriers limiting a new antifungal pipeline. DectiSomes represent a new drug delivery platform that enhances antifungal efficacy for diverse fungal pathogens and reduces host toxicity for current and future antifungals. DectiSomes employ pathogen receptor proteins - C-type lectins - to target drug-loaded liposomes to conserved fungal cognate ligands and away from host cells. DectiSomes represent one leap forward for urgently needed effective pan-antifungal therapy. Herein, we discuss the problems of battling fungal diseases and the state of DectiSome development.


Assuntos
Antifúngicos , Micoses , Humanos , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Lipossomos , Lectinas Tipo C/uso terapêutico , Micoses/tratamento farmacológico
16.
J Fungi (Basel) ; 8(4)2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35448583

RESUMO

Mucormycosis (a.k.a. zygomycosis) is an often-life-threatening disease caused by fungi from the ancient fungal division Mucoromycota. Globally, there are nearly a million people with the disease. Rhizopus spp., and R. delemar (R. oryzae, R. arrhizus) in particular, are responsible for most of the diagnosed cases. Pulmonary, rhino-orbito-cerebral, and invasive mucormycosis are most effectively treated with amphotericin B (AmB) and particularly with liposomal formulations (e.g., AmBisome®). However, even after antifungal therapy, there is still a 50% mortality rate. Hence, there is a critical need to improve therapeutics for mucormycosis. Targeting AmB-loaded liposomes (AmB-LLs) with the pathogen receptor Dectin-1 (DEC1-AmB-LLs) to the beta-glucans expressed on the surface of Aspergillus fumigatus and Candida albicans lowers the effective dose required to kill cells relative to untargeted AmB-LLs. Because Dectin-1 is an immune receptor for R. delemar infections and may bind it directly, we explored the Dectin-1-mediated delivery of liposomal AmB to R. delemar. DEC1-AmB-LLs bound 100- to 1000-fold more efficiently to the exopolysaccharide matrix of R. delemar germlings and mature hyphae relative to AmB-LLs. DEC1-AmB-LLs delivering sub-micromolar concentrations of AmB were an order of magnitude more efficient at inhibiting and/or killing R. delemar than AmB-LLs. Targeted antifungal drug-loaded liposomes have the potential to improve the treatment of mucormycosis.

17.
Plant Physiol ; 152(1): 217-25, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19897606

RESUMO

Phosphate (Pi) availability is a major constraint to plant growth. Consequently, plants have evolved complex adaptations to tolerate low Pi conditions. Numerous genes implicated in these adaptations have been identified, but their chromatin-level regulation has not been investigated. The nuclear actin-related protein ARP6 is conserved among all eukaryotes and is an essential component of the SWR1 chromatin remodeling complex, which regulates transcription via deposition of the H2A.Z histone variant into chromatin. Here, we demonstrate that ARP6 is required for proper H2A.Z deposition at a number of Pi starvation response (PSR) genes in Arabidopsis (Arabidopsis thaliana). The loss of H2A.Z at these target loci results in their derepression in arp6 mutants and correlates with the presence of multiple Pi-starvation-related phenotypes, including shortened primary roots and increases in the number and length of root hairs, as well as increased starch accumulation and phosphatase activity in shoots. Our data suggest a model for chromatin-level control of Pi starvation responses in which ARP6-dependent H2A.Z deposition modulates the transcription of a suite of PSR genes.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Histonas/metabolismo , Fosfatos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Histonas/genética , Illicium , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Mutação , Monoéster Fosfórico Hidrolases/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Plântula
19.
mBio ; 12(1)2021 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-33622715

RESUMO

Invasive fungal diseases cause millions of deaths each year. There are currently approximately 300,000 acute cases of aspergillosis, most of which result from a pulmonary infection of immunocompromised patients by the common soil organism and opportunistic pathogen Aspergillus fumigatus Patients are treated with antifungal drugs, such as amphotericin B (AmB). However, AmB has serious limitations due to human organ toxicity. AmB is slightly less toxic if loaded in liposomes, such as AmBisome or AmB-loaded liposomes (AmB-LLs). Even with antifungal therapy, recurrent infections are common, and 1-year fatality rates may exceed 50%. We have previously shown that coating AmB-LLs with the extracellular oligomannan-binding domain of the C-type lectin receptor Dectin-2 (DEC2-AmB-LLs) effectively targets DEC2-AmB-LLs to cell walls, exopolysaccharide matrices, and biofilms of fungal pathogens in vitroIn vitro, DEC2-AmB-LLs reduce the effective dose of AmB for 95% inhibition and killing of A. fumigatus 10-fold compared to that of untargeted AmB-LLs. Herein we tested the antifungal activity of DEC2-AmB-LLs relative to that of untargeted AmB-LLs in immunosuppressed mice with pulmonary aspergillosis. Remarkably, DEC2-AmB-LLs bound 30-fold more efficiently to A. fumigatus at sites of infection in the lungs. Furthermore, Dectin-2-targeted liposomes delivering AmB at a dose of 0.2 mg/kg of body weight significantly reduced the fungal burden in lungs compared to results with untargeted AmB-LLs at 0.2 mg/kg and micellar voriconazole at 20 mg/kg and prolonged mouse survival. By dramatically increasing the efficacy of antifungal drugs at low doses, targeted liposomes have the potential to create a new clinical paradigm to treat diverse fungal diseases.IMPORTANCE Invasive aspergillosis (IA) generally results from a pulmonary infection of immunocompromised patients by the common soil organism and opportunistic pathogen Aspergillus fumigatus The susceptible population has expanded rapidly due to the increased number of cancer patients with immunocompromising chemotherapy and transplant patients taking immunosuppressants. Patients are treated with antifungals, such as liposomal amphotericin B, with per-patient costs exceeding $50,000 in the United States. However, AmB has serious side effects due to host toxicity, which limits its usage and contributes to the lack of fungal clearance in patients at safe doses. Fifty percent of IA patients die within a year. Herein, we employed liposomal amphotericin B coated with the innate immune receptor Dectin-2 to direct antifungals specifically to the fungal pathogen. Using two mouse models of pulmonary aspergillosis, we demonstrate that Dectin-2-targeted delivery of amphotericin B to A. fumigatus resulted in remarkably higher efficacy than that of the untargeted antifungal formulations.


Assuntos
Antifúngicos/uso terapêutico , Aspergillus fumigatus/efeitos dos fármacos , Parede Celular/metabolismo , Lectinas Tipo C/metabolismo , Lectinas Tipo C/uso terapêutico , Lipossomos/química , Aspergilose Pulmonar/tratamento farmacológico , Anfotericina B/metabolismo , Anfotericina B/uso terapêutico , Animais , Parede Celular/efeitos dos fármacos , Feminino , Lectinas Tipo C/genética , Lipossomos/uso terapêutico , Camundongos , Neutropenia
20.
Nat Sci Sleep ; 13: 457-466, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33790678

RESUMO

INTRODUCTION: Obstructive sleep apnea (OSA) results in chronic intermittent hypoxia leading to systemic inflammation, increases in pro-inflammatory cytokines TNF-Alpha and IL-6, and increased risk for a number of life threatening medical disorders such as cardiovascular and kidney disease. METHODS: A BioPlex Array was used to examined the serum levels of four cytokines also expressed in endothelial cells and/or macrophages and associated with cardiovascular and kidney disease risk. RESULTS: Relative to untreated OSA patients, airways treated OSA patients had a 5.4-fold higher median level of MMP2 (p = 9.1x10-11), a 1.4-fold higher level of TWEAK (p = 1.8x10-7), a 1.7-fold higher level of CD163 (p = 1.4x10-6), but a 2.0-fold lower level of MMP3 (p = 7.9x10-7). Airway treatment resulted in levels more similar to or indistinguishable from control subjects. Both t-SNE or UMAP analysis of the global structure of these multi-dimensional data revealed two data clusters, one populated primarily with data for controls and most airways treated OSA patients and a second populated primarily with data for OSA patients. DISCUSSION: We discuss a concept in which the aberrant levels of these cytokines in untreated OSA patients may represent a chronic response after years of experiencing intermittent nightly hypoxia, which attenuated the acute response to hypoxia. A balanced therapeutic correction of the aberrant levels of these cytokines may limit the progression of CVD and kidney disease in OSA patients.

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