RESUMEN

Acyl carrier proteins (ACPs) are central to many primary and secondary metabolic pathways. In E. coli fatty acid biosynthesis (FAB), the central ACP, AcpP, transports intermediates to a suite of partner proteins (PP) for iterative modification and elongation. The regulatory protein-protein interactions that occur between AcpP and the PP in FAB are poorly understood due to the dynamic and transient nature of these interactions. Solution-state NMR spectroscopy can reveal information at the atomic level through experiments such as the 2D heteronuclear single quantum coherence (HSQC). The following protocol describes NMR HSQC titration experiments that can elucidate biomolecular recognition events.

Asunto(s)

Proteínas de Escherichia coli , Escherichia coli , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Espectroscopía de Resonancia Magnética , Imagen por Resonancia Magnética

RESUMEN

[This corrects the article DOI: 10.3389/fmicb.2015.00075.].

RESUMEN

α-Glycosidase is an essential target for the management of postprandial serum glucose in diabetic patients. Therefore, the interest has been growing in the screening of α-glycosidase inhibitor from natural resource. In the present study, the structure and α-glycosidase inhibitory activity of a polysaccharide (named as ACPP-1) from Aconitum coreanum were investigated. Based on the results from high performance gel permeation chromatography, GC-MS and 1D/2D nuclear magnetic resonance spectroscopy, ACPP-1 was a highly-linear polysaccharide with a molecular weight of 34.0 kD and containing over 90 % of glucose. It was composed of (1→4)-α-d-Glcp and α-Araf. ACPP-1 exhibited a dose-dependent inhibitory eff ;ect against α-glycosidase activity in vitro and the IC50 value was ∼0.8 mg/mL. In oral starch tolerance test, treatment with ACPP-1 (800 mg/kg) significantly improved the starch tolerance in mice. Taken together, this study provided a potential intervention and management for postprandial hyperglycemia by the polysaccharide fraction from A. coreanum.

Asunto(s)

Aconitum/química , Inhibidores de Glicósido Hidrolasas/química , Polisacáridos/química , alfa-Glucosidasas/química , Animales , Cromatografía en Gel , Inhibidores de Glicósido Hidrolasas/farmacología , Humanos , Ratones , Peso Molecular , Extractos Vegetales/química , Extractos Vegetales/farmacología , Polisacáridos/farmacología , Polisacáridos/ultraestructura , alfa-Glucosidasas/farmacología , alfa-Glucosidasas/ultraestructura

RESUMEN

[This corrects the article DOI: 10.3389/fmicb.2015.00075.].

RESUMEN

BACKGROUND: Carbapenem-resistant Acinetobacter baumannii (A. baumannii) was on the top of the list of the most threatening bacteria published by the WHO in 2017. Antisense oligonucleotides (ASOs) based therapy is a promising strategy for combating Multi-Drug Resistant (MDR) bacteria because of its high specificity, easy design and lower induction of resistance, but poor cellular uptake by bacteria has restricted the further utilization of this therapy. METHODS: Here, we used CADY, a secondary amphipathic peptide of 20 residues that could successfully carry siRNA into mammalian cells, to prepare CADY/ASOs nanoparticles (CADY-NPs) targeting acpP (encoding acyl carrier protein), and evaluated the uptake features, the inhibitory effects of CADY-NPs on gene expression and the growth of MDR-A. baumannii. RESULTS: We found that CADY-NPs could be quickly internalized by drug-sensitive and MDR-A. baumannii in an energy independent manner, which could be restrained by chlorpromazine (an inhibitor of clathrin mediated endocytosis) significantly. In addition, CADY-NPs targeting acpP concentrationdependently retarded the growth of MDR-A. baumannii, which was associated with the decreased expression of targeted genes in A. baumannii. CONCLUSION: In conclusion, our research is the first to demonstrate that CADY can deliver ASOs into bacteria and provide a novel strategy for the treatment of MDR-A. baumannii.

Asunto(s)

Acinetobacter baumannii/efectos de los fármacos , Antibacterianos/farmacología , Péptidos de Penetración Celular/farmacología , Sistemas de Liberación de Medicamentos , Oligonucleótidos Antisentido/farmacología , Tensoactivos/farmacología , Acinetobacter baumannii/crecimiento & desarrollo , Antibacterianos/química , Péptidos de Penetración Celular/química , Pruebas de Sensibilidad Microbiana , Nanopartículas/química , Oligonucleótidos Antisentido/química , Tensoactivos/química

RESUMEN

Choroid plexus papillomas (CPPs) are rare, benign tumors that can arise in young children. Most pediatric patients present with signs of hydrocephalus and require immediate treatment. The natural history of choroid plexus tumors in children without hydrocephalus is poorly defined. In this report, the authors present the very rare case of a child without hydrocephalus but with two intraventricular choroid plexus tumors discovered shortly after birth. Initial imaging had been performed for seizures and showed agenesis of the corpus callosum and enhancing tumors in the third and left lateral ventricles. Sequential imaging demonstrated rapid growth of both tumors. The lateral tumor was removed when the child was 3 months of age. A histological examination of the specimen showed benign features with an elevated mitotic rate. Given the patient's age of under 3 years, the diagnosis was WHO grade I CPP. The third ventricle tumor grew rapidly. A second surgery was performed and this tumor was resected. Again, the pathological diagnosis was WHO grade I CPP. The authors present this rare case and discuss the current relevant literature.

RESUMEN

Aberrant protein phosphorylation is one of the hallmarks of cancer cells, and in many cases a prerequisite to sustain tumor development and progression. Like protein kinases, protein phosphatases are key regulators of cell signaling. However, their contribution to aberrant signaling in cancer cells is overall less well appreciated, and therefore, their clinical potential remains largely unexploited. In this review, we provide an overview of tumor suppressive protein phosphatases in human cancer. Along their mechanisms of inactivation in defined cancer contexts, we give an overview of their functional roles in diverse signaling pathways that contribute to their tumor suppressive abilities. Finally, we discuss their emerging roles as predictive or prognostic markers, their potential as synthetic lethality targets, and the current feasibility of their reactivation with pharmacologic compounds as promising new cancer therapies. We conclude that their inclusion in clinical practice has obvious potential to significantly improve therapeutic outcome in various ways, and should now definitely be pushed forward.

Asunto(s)

Neoplasias/enzimología , Fosfoproteínas Fosfatasas/metabolismo , Transducción de Señal , Proteínas Supresoras de Tumor/metabolismo , Humanos , Neoplasias/genética , Neoplasias/patología , Neoplasias/terapia , Fosfoproteínas Fosfatasas/genética , Proteínas Supresoras de Tumor/genética

RESUMEN

Atypical choroid plexus papillomas can metastasize in the form of leptomeningeal seeding. Postoperative chemotherapy is the recommended first-line treatment when gross-total removal is not achieved or in cases of disseminated disease. Here the authors report on 2 children with atypical choroid plexus papillomas and MRI findings of diffuse leptomeningeal enhancement at diagnosis, later presenting with spontaneous resolution of the leptomeningeal involvement after removal of the primary lesions. Observations in this report expand our knowledge about the natural history and biological behavior of these tumors and highlight the role of close neuroimaging surveillance in the management of atypical choroid plexus papillomas in cases with MRI evidence of diffuse leptomeningeal enhancement at presentation.

Asunto(s)

Neoplasias Meníngeas/diagnóstico por imagen , Meninges/diagnóstico por imagen , Papiloma del Plexo Coroideo/diagnóstico por imagen , Papiloma del Plexo Coroideo/cirugía , Medios de Contraste , Gadolinio , Humanos , Lactante , Imagen por Resonancia Magnética , Masculino

RESUMEN

As a potent therapeutic agent, small interfering RNA (siRNA) has been exploited to silence critical genes involved in tumor initiation and progression. However, development of a desirable delivery system is required to overcome the unfavorable properties of siRNA such as its high degradability, molecular size, and negative charge to help increase its accumulation in tumor tissues and promote efficient cellular uptake and endosomal/lysosomal escape of the nucleic acids. In this study, we developed a new activatable cell-penetrating peptide (ACPP) that is responsive to an acidic tumor microenvironment, which was then used to modify the surfaces of siRNA-loaded liposomes. The ACPP is composed of a cell-penetrating peptide (CPP), an acid-labile linker (hydrazone), and a polyanionic domain, including glutamic acid and histidine. In the systemic circulation (pH 7.4), the surface polycationic moieties of the CPP (polyarginine) are "shielded" by the intramolecular electrostatic interaction of the inhibitory domain. When exposed to a lower pH, a common property of solid tumors, the ACPP undergoes acid-catalyzed breakage at the hydrazone site, and the consequent protonation of histidine residues promotes detachment of the inhibitory peptide. Subsequently, the unshielded CPP would facilitate the cellular membrane penetration and efficient endosomal/lysosomal evasion of liposomal siRNA. A series of investigations demonstrated that once exposed to an acidic pH, the ACPP-modified liposomes showed elevated cellular uptake, downregulated expression of polo-like kinase 1, and augmented cell apoptosis. In addition, favorable siRNA avoidance of the endosome/lysosome was observed in both MCF-7 and A549 cells, followed by effective cytoplasmic release. In view of its acid sensitivity and therapeutic potency, this newly developed pH-responsive and ACPP-mediated liposome system represents a potential platform for siRNA-based cancer treatment.

Asunto(s)

Antineoplásicos/farmacología , Péptidos de Penetración Celular/administración & dosificación , Sistemas de Liberación de Medicamentos/métodos , Liposomas/química , ARN Interferente Pequeño/administración & dosificación , Antineoplásicos/química , Apoptosis/efectos de los fármacos , Apoptosis/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Línea Celular Tumoral , Péptidos de Penetración Celular/química , Endosomas/efectos de los fármacos , Endosomas/metabolismo , Ácido Glutámico/química , Histidina/química , Humanos , Hidrazonas/química , Concentración de Iones de Hidrógeno , Células MCF-7 , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , ARN Interferente Pequeño/farmacología , Microambiente Tumoral/efectos de los fármacos , Microambiente Tumoral/genética , Quinasa Tipo Polo 1

RESUMEN

Mechanical properties such as physical constraint and pushing of chromosomes are thought to be important for chromosome segregation in Escherichia coli and it could be mediated by a hypothetical molecular "tether." However, the actual tether that mediates these features is not known. We previously described that SecA (Secretory A) and Secretory Y (SecY), components of the membrane protein translocation machinery, and AcpP (Acyl carrier protein P) were involved in chromosome segregation and homeostasis of DNA topology. In the present work, we performed three-dimensional deconvolution of microscopic images and time-lapse experiments of these proteins together with MukB and DNA topoisomerases, and found that these proteins embraced the structures of tortuous nucleoids with condensed regions. Notably, SecA, SecY, and AcpP dynamically localized in cells, which was interdependent on each other requiring the ATPase activity of SecA. Our findings imply that the membrane protein translocation machinery plays a role in the maintenance of proper chromosome partitioning, possibly through "tethering" of MukB [a functional homolog of structural maintenance of chromosomes (SMC) proteins], DNA gyrase, DNA topoisomerase IV, and SeqA (Sequestration A).

RESUMEN

Cholesterol homeostasis is strictly maintained to prevent abnormal biological processes that arise from excessive accumulation of cholesterol in tissues. Although dyslipidemia causes reproductive dysfunction and endocrine disruption in male rats, regulatory factors and mechanisms have not been clearly demonstrated. Therefore, the present study investigated the histology of male reproductive organs and the expression of prostatic acid phosphatase (also known as Acpp) that is secreted by cuboidal epithelium of the prostate gland in response to a normal diet and a high-cholesterol diet. The high cholesterol diet increased total cholesterol and low density lipoprotein (LDL) levels and decreased high density lipoprotein (HDL) levels. Histological analyses showed considerable alterations in the prostate indicating excessive papillary projections within the acinar lumen in response to the high cholesterol diet. In addition, Acpp expression was decreased in the penis of rats fed the high cholesterol diet and it was predominantly localized in the urethral epithelium and penile follicle that is precursor of penile spines. Moreover, Acpp was reduced slightly in the testes, but differential expression of Acpp in the prostate in response to dietary cholesterol was not detected. Furthermore, target microRNAs (miRs) of Acpp such as miR-192 and miR-215 regulated Acpp gene expression at the post-transcriptional levels by binding to specific sites within its 3'-UTR. These results indicate that Acpp plays an important role in growth and development of the penis of rats, and its expression is modulated at epigenomic levels via specific miRs.

Asunto(s)

Colesterol en la Dieta/metabolismo , Regulación Enzimológica de la Expresión Génica , Próstata/metabolismo , Proteínas Tirosina Fosfatasas/metabolismo , Testículo/metabolismo , Fosfatasa Ácida , Animales , Grasas de la Dieta/metabolismo , Epigenómica , Hibridación in Situ , Masculino , MicroARNs/metabolismo , Pene/metabolismo , Procesamiento Postranscripcional del ARN , Ratas , Ratas Sprague-Dawley

RESUMEN

Prostatic acid phosphatase (ACPP) is a glycoprotein that is mainly synthesized and secreted by glandular epithelial cells (GE) of the prostate, and it is well known as a biomarker for prostate cancer. Although ACPP was used as prognostic/diagnostic indicator and studied to elucidate regulatory mechanism(s) during several decades in humans, its role is not clearly understood. Gene profiling data using a chicken DNA microarray revealed that ACPP increased significantly during remodeling and recrudescence of the oviduct in response to estrogen. Thus, in this study, we investigated the expression and hormonal regulation of ACPP gene in the reproductive tracts of chickens. ACPP was specifically detected in the luminal cells (LE) and GE of chicken oviduct, and diethylstilbestrol (a synthetic nonsteroidal estrogen) stimulated its expression during development of the oviduct. In addition, ACPP mRNA and protein were localized to LE and GE during the regeneration phase of the oviduct of laying hens during induced molting. Furthermore, ACPP mRNA and protein were abundant in GE of ovarian carcinoma, but not in normal ovaries. Moreover, strong expression of ACPP protein was detected in epithelial cells of cancerous ovaries from women. Collectively, results of the present study are the first to show that ACPP is a novel estrogen-stimulated gene in the oviductal epithelial cells of the chicken and that its expression increases significantly in epithelial cells of ovarian carcinoma, which indicates that it may be a candidate biomarker for diagnosis of epithelia-derived ovarian cancer in women.

Asunto(s)

Carcinoma/enzimología , Dietilestilbestrol/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Neoplasias Ováricas/enzimología , Oviductos/enzimología , Proteínas Tirosina Fosfatasas/metabolismo , Fosfatasa Ácida , Animales , Proteínas Aviares/genética , Proteínas Aviares/metabolismo , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Pollos , Femenino , Humanos , Oviductos/efectos de los fármacos , Proteínas Tirosina Fosfatasas/genética

RESUMEN

Much of microbial life on Earth grows and reproduces under the elevated hydrostatic pressure conditions that exist in deep-ocean and deep-subsurface environments. In this study adaptive laboratory evolution (ALE) experiments were conducted to investigate the possible modification of the piezosensitive Escherichia coli for improved growth at high pressure. After approximately 500 generations of selection, a strain was isolated that acquired the ability to grow at pressure non-permissive for the parental strain. Remarkably, this strain displayed growth properties and changes in the proportion and regulation of unsaturated fatty acids that indicated the acquisition of multiple piezotolerant properties. These changes developed concomitantly with a change in the gene encoding the acyl carrier protein, which is required for fatty acid synthesis.