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1.
Mol Cell ; 81(13): 2705-2721.e8, 2021 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-33974911

RESUMEN

The TSC complex is a critical negative regulator of the small GTPase Rheb and mTORC1 in cellular stress signaling. The TSC2 subunit contains a catalytic GTPase activating protein domain and interacts with multiple regulators, while the precise function of TSC1 is unknown. Here we provide a structural characterization of TSC1 and define three domains: a C-terminal coiled-coil that interacts with TSC2, a central helical domain that mediates TSC1 oligomerization, and an N-terminal HEAT repeat domain that interacts with membrane phosphatidylinositol phosphates (PIPs). TSC1 architecture, oligomerization, and membrane binding are conserved in fungi and humans. We show that lysosomal recruitment of the TSC complex and subsequent inactivation of mTORC1 upon starvation depend on the marker lipid PI3,5P2, demonstrating a role for lysosomal PIPs in regulating TSC complex and mTORC1 activity via TSC1. Our study thus identifies a vital role of TSC1 in TSC complex function and mTORC1 signaling.


Asunto(s)
Chaetomium , Proteínas Fúngicas , Lisosomas , Diana Mecanicista del Complejo 1 de la Rapamicina , Fosfatos de Fosfatidilinositol , Serina C-Palmitoiltransferasa , Chaetomium/química , Chaetomium/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Lisosomas/química , Lisosomas/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/química , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Fosfatos de Fosfatidilinositol/química , Fosfatos de Fosfatidilinositol/metabolismo , Serina C-Palmitoiltransferasa/química , Serina C-Palmitoiltransferasa/metabolismo
2.
Chem Biodivers ; : e202400680, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38748618

RESUMEN

The study aimed to assess the chemical composition of Miconia ibaguensis leaves extracts and fractions obtained from the ethanolic extract (EE), along with evaluating their antifungal, antibacterial, antidiabetic, and antioxidant activities. The ethyl acetate fraction (EAF) exhibited potent antifungal activity against Candida spp (1.95 - 3.90 µg mL-1) and potent antioxidant activity in the DPPH (1.74 ± 0.07 µg mL-1), FRAP (654.01 ± 42.09 µmol ETrolox/gsample), and ORAC (3698.88 ± 37.28 µmol ETrolox/gsample) methods. The EE displayed inhibition against the α-amylase enzyme (8.42 ± 0.05 µg mL-1). Flavonoids, hydrolysable tannins, triterpenoids, and phenolic acids, identified in the EE and fractions via (-)-HPLC-ESI-MS/MS analysis, were found to contribute to the species' biological activity potentially. These findings suggest promising avenues for further research and potential applications in pharmacology and natural products, offering new possibilities in the fight against global health issues.

3.
Brain ; 144(10): 3020-3035, 2021 11 29.
Artículo en Inglés | MEDLINE | ID: mdl-33964137

RESUMEN

Leukodystrophies are a heterogeneous group of rare inherited disorders that mostly involve the white matter of the CNS. These conditions are characterized by primary glial cell and myelin sheath pathology of variable aetiology, which causes secondary axonal degeneration, generally emerging with disease progression. Whole exome sequencing performed in five large consanguineous nuclear families allowed us to identify homozygosity for two recurrent missense variants affecting highly conserved residues of RNF220 as the causative event underlying a novel form of leukodystrophy with ataxia and sensorineural deafness. We report these two homozygous missense variants (p.R363Q and p.R365Q) in the ubiquitin E3 ligase RNF220 as the underlying cause of this novel form of leukodystrophy with ataxia and sensorineural deafness that includes fibrotic cardiomyopathy and hepatopathy as associated features in seven consanguineous families. Mass spectrometry analysis identified lamin B1 as the RNF220 binding protein and co-immunoprecipitation experiments demonstrated reduced binding of both RNF220 mutants to lamin B1. We demonstrate that RNF220 silencing in Drosophila melanogaster specifically affects proper localization of lamin Dm0, the fly lamin B1 orthologue, promotes its aggregation and causes a neurodegenerative phenotype, strongly supporting the functional link between RNF220 and lamin B1. Finally, we demonstrate that RNF220 plays a crucial role in the maintenance of nuclear morphology; mutations in primary skin fibroblasts determine nuclear abnormalities such as blebs, herniations and invaginations, which are typically observed in cells of patients affected by laminopathies. Overall, our data identify RNF220 as a gene implicated in leukodystrophy with ataxia and sensorineural deafness and document a critical role of RNF220 in the regulation of nuclear lamina. Our findings provide further evidence on the direct link between nuclear lamina dysfunction and neurodegeneration.


Asunto(s)
Alelos , Ataxia/genética , Sordera/genética , Laminopatías/genética , Mutación/genética , Ubiquitina-Proteína Ligasas/genética , Adolescente , Secuencia de Aminoácidos , Animales , Ataxia/diagnóstico , Células COS , Niño , Chlorocebus aethiops , Sordera/diagnóstico , Drosophila , Femenino , Células HEK293 , Humanos , Laminopatías/diagnóstico , Masculino , Linaje , Adulto Joven
4.
Pathologica ; 113(6): 475-480, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34974555

RESUMEN

Rectal prolapse is a disorder in which the rectum protrudes from the anal canal. Solitary rectal ulcer may coexist. Both conditions have been associated with chronic constipation and excessive straining during defecation. Rectal prolapse has been rarely reported in women suffering from anorexia nervosa. Lack of rectal support because of loss of ischiorectal fat has been proposed as one of the possible mechanisms in this condition, together with chronic constipation and abuse of laxative. We report the case of an anorexic woman with a severe rectal prolapse and bleeding requiring urgent Altmeier's procedure. Surgery was complicated by dehiscence of the anastomosis and volvulus, requiring ileostomy and laciniae debridement. Pathological analysis of all the surgical samples taken from different abdominal sites highlighted changes in the visceral adipose tissue consisting in nodular aggregates of small adipocytes dispersed in a myxoid matrix surrounding blood vessels within abundant fibrosis. The morphologic features resemble those observed in primordial fetal fat and are comparable to those observed in cancer associated cachexia. The diffuse myxoid degeneration of visceral adipose tissue may play a role in the pathogenesis of rectal prolapse in patients with anorexia nervosa. Besides starvation, the mechanism sustaining myxoid degeneration of the adipose tissue is not entirely clear. Whenever possible improving nutritional and clinical conditions should be ideal before any surgical approach.


Asunto(s)
Depresores del Apetito , Enfermedades del Recto , Prolapso Rectal , Femenino , Humanos , Grasa Intraabdominal , Prolapso Rectal/complicaciones , Prolapso Rectal/cirugía , Úlcera
5.
Chemistry ; 26(71): 17176-17182, 2020 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-32720444

RESUMEN

A dicationic imidazolium salt is described and investigated towards its application for gene transfer. The polar head group and the long alkyl chains in the backbone contribute to a lipid-like behavior, while an alkyl ammonium group provides the ability for crucial electrostatic interaction for the transfection process. Detailed biophysical studies regarding its impact on biological membrane models and the propensity of vesicle fusion are presented. Fluorescence spectroscopy, atomic force microscopy and confocal fluorescence microscopy show that the imidazolium salt leads to negligible changes in lipid packing, while displaying distinct vesicle fusion properties. Cell culture experiments reveal that mixed liposomes containing the novel imidazolium salt can serve as plasmid DNA delivery vehicles. In contrast, a structurally similar imidazolium salt without a second positive charge showed no ability to support DNA transfection into cultured cells. Thus, we introduce a novel and variable structural motif for cationic lipids, expanding the field of lipofection agents.


Asunto(s)
Cationes/química , Imidazoles/química , Lípidos , Liposomas , ADN/química , Transfección
6.
J Inherit Metab Dis ; 41(6): 1015-1025, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-29967951

RESUMEN

BACKGROUND AND AIMS: Glycogen storage disease type Ib (GSD1b) is a rare metabolic and immune disorder caused by a deficiency in the glucose-6-phosphate transporter (G6PT) and characterized by impaired glucose homeostasis, myeloid dysfunction, and long-term risk of hepatocellular adenomas. Despite maximal therapy, based on a strict diet and on granulocyte colony-stimulating factor treatment, long-term severe complications still develop. Understanding the pathophysiology of GSD1b is a prerequisite to develop new therapeutic strategies and depends on the availability of animal models. The G6PT-KO mouse mimics the human disease but is very fragile and rarely survives weaning. We generated a conditional G6PT-deficient mouse as an alternative model for studying the long-term pathophysiology of the disease. We utilized this conditional mouse to develop an inducible G6PT-KO model to allow temporally regulated G6PT deletion by the administration of tamoxifen (TM). METHODS: We generated a conditional G6PT-deficient mouse utilizing the CRElox strategy. Histology, histochemistry, and phenotype analyses were performed at different times after TM-induced G6PT inactivation. Neutrophils and monocytes were isolated and analyzed for functional activity with standard techniques. RESULTS: The G6PT-inducible KO mice display the expected disturbances of G6P metabolism and myeloid dysfunctions of the human disorder, even though with a milder intensity. CONCLUSIONS: TM-induced inactivation of G6PT in these mice leads to a phenotype which mimics that of human GSD1b patients. The conditional mice we have generated represent an excellent tool to study the tissue-specific role of the G6PT gene and the mechanism of long-term complications in GSD1b.


Asunto(s)
Antiportadores/deficiencia , Modelos Animales de Enfermedad , Glucosa/metabolismo , Enfermedad del Almacenamiento de Glucógeno Tipo I/genética , Homeostasis , Proteínas de Transporte de Monosacáridos/deficiencia , Animales , Antiportadores/genética , Enfermedad del Almacenamiento de Glucógeno Tipo I/etiología , Enfermedad del Almacenamiento de Glucógeno Tipo I/patología , Ratones , Ratones Noqueados , Proteínas de Transporte de Monosacáridos/genética , Neutropenia/etiología , Tamoxifeno/administración & dosificación
7.
Antonie Van Leeuwenhoek ; 111(9): 1661-1672, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29488182

RESUMEN

The alcoholic fermentation for fuel ethanol production in Brazil occurs in the presence of several microorganisms present with the starter strain of Saccharomyces cerevisiae in sugarcane musts. It is expected that a multitude of microbial interactions may exist and impact on the fermentation yield. The yeast Dekkera bruxellensis and the bacterium Lactobacillus fermentum are important and frequent contaminants of industrial processes, although reports on the effects of both microorganisms simultaneously in ethanolic fermentation are scarce. The aim of this work was to determine the effects and interactions of both contaminants on the ethanolic fermentation carried out by the industrial yeast S. cerevisiae PE-2 in two different feedstocks (sugarcane juice and molasses) by running multiple batch fermentations with the starter yeast in pure or co-cultures with D. bruxellensis and/or L. fermentum. The fermentations contaminated with D. bruxellensis or L. fermentum or both together resulted in a lower average yield of ethanol, but it was higher in molasses than that of sugarcane juice. The decrease in the CFU number of S. cerevisiae was verified only in co-cultures with both D. bruxellensis and L. fermentum concomitant with higher residual sucrose concentration, lower glycerol and organic acid production in spite of a high reduction in the medium pH in both feedstocks. The growth of D. bruxellensis was stimulated in the presence of L. fermentum resulting in a more pronounced effect on the fermentation parameters than the effects of contamination by each microorganism individually.


Asunto(s)
Biocombustibles/microbiología , Dekkera/metabolismo , Etanol , Fermentación , Microbiología Industrial , Limosilactobacillus fermentum/metabolismo , Saccharomyces cerevisiae/metabolismo , Ácido Acético , Brasil , Recuento de Células , Técnicas de Cocultivo , Dekkera/crecimiento & desarrollo , Glicerol , Concentración de Iones de Hidrógeno , Limosilactobacillus fermentum/crecimiento & desarrollo , Interacciones Microbianas , Melaza , Saccharomyces cerevisiae/crecimiento & desarrollo , Saccharum/metabolismo , Saccharum/microbiología , Sacarosa
8.
Sci Rep ; 14(1): 11132, 2024 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-38750088

RESUMEN

Candida species have been responsible for a high number of invasive infections worldwide. In this sense, Rottlerin has demonstrated a wide range of pharmacological activities. Therefore, this study aimed to evaluate the antifungal, antibiofilm and antivirulence activity of Rottlerin in vitro against Candida spp. and its toxicity and antifungal activity in vivo. Rottlerin showed antifungal activity against all yeasts evaluated, presenting Minimum Inhibitory and Fungicidal Concentration (MIC and MFC) values of 7.81 to > 1000 µg/mL. Futhermore, it was able to significantly inhibit biofilm production, presenting Biofilm Inhibitory Concentration (MICB50) values that ranged from 15.62 to 250 µg/mL and inhibition of the cell viability of the biofilm by 50% (IC50) from 2.24 to 12.76 µg/mL. There was a considerable reduction in all hydrolytic enzymes evaluated, with emphasis on hemolysin where Rottlerin showed a reduction of up to 20%. In the scanning electron microscopy (SEM) analysis, Rottlerin was able to completely inhibit filamentation by C. albicans. Regarding in vivo tests, Rottlerin did not demonstrate toxicity at the therapeutic concentrations demonstrated here and was able to increase the survival of C. elegans larvae infected. The results herein presented are innovative and pioneering in terms of Rottlerin's multipotentiality against these fungal infections.


Asunto(s)
Acetofenonas , Antifúngicos , Benzopiranos , Biopelículas , Pruebas de Sensibilidad Microbiana , Biopelículas/efectos de los fármacos , Antifúngicos/farmacología , Benzopiranos/farmacología , Animales , Acetofenonas/farmacología , Caenorhabditis elegans/efectos de los fármacos , Candida/efectos de los fármacos , Candidiasis/tratamiento farmacológico , Candida albicans/efectos de los fármacos
9.
SAGE Open Nurs ; 10: 23779608241236290, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38464600

RESUMEN

Introduction: Occupational stress affects health professionals; however, no literature was found on the middle-range theory for this outcome in health professionals. Methods: Methodological study for the theoretical validation of a nursing diagnosis using the theoretical framework of Walker and Avant and the Betty Neuman systems models. The research was conducted in five stages: comprehension of the system model; selection and review of studies; development of the conceptual-theoretical-empirical structure; elaboration of a diagram and proposition of a nursing diagnosis; and evaluation of the empirical adequacy of the theory and validity of the system model. These steps were conducted using a scoping review and a sample of 138 articles selected in the Scopus, Web of Science, MEDLINE/PubMed, CINAHL, PsycINFO, LILACS, Science Direct, Cochrane Library, and Google Scholar databases. A data extraction instrument was developed, and study variables (attributes, antecedents, and clinical consequences) were analyzed using descriptive statistics (absolute and relative frequencies) and presented in tables. Results: The middle-range theory comprised 16 concepts, 20 propositions, and one diagram. A total of 15 related factors, 29 defining characteristics, six at-risk populations, and one associated condition were indicated to propose the nursing diagnosis for occupational stress. Conclusion: The middle-range theory supported elaborating elements to propose a nursing diagnosis for occupational stress.

10.
J Clin Med ; 12(9)2023 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-37176556

RESUMEN

Persistent Müllerian Duct Syndrome (PMDS) is a rare autosomal recessive disorder of sex development characterized by the presence of fallopian tubes, uterus and upper one-third of the vagina in individuals with XY genotype and normal male phenotype. The main complications of PMDS are infertility and the rare risk of malignant degeneration of both testicular and Müllerian derivatives. We report the case of a 49-year-old man who, during repair of an incisional hernia, was incidentally found to have a uterine-like structure posterior to the bladder. In the past at the age of 18 months, he had undergone bilateral orchidopexies for bilateral cryptorchidism. The intraoperative decision was to preserve the uterine-like structure and make a more accurate diagnosis postoperatively. Evaluation revealed an XY chromosome and imaging consistent with PMDS. The patient was informed about the risk of neoplastic transformation of the residual Müller ducts and was offered surgical treatment, which he declined. Subsequent follow-up imaging studies, including testicular and pelvic ultrasound, were negative for findings suggestive of malignant testicular and Mullerian derivative degeneration. A review of the international literature showed that, when a decision is taken to remove the Mullerian derivatives, laparoscopy and especially robotic surgery allow for the successful removal of Müllerian derivatives. Whenever the removal of these structures is not possible or the patient refuses to undergo surgery, it is necessary to inform the patient of the need for adequate follow-up. Patients should undergo regular pelvic imaging examination and MRI might be a better method for that purpose.

11.
Cell Rep ; 42(12): 113501, 2023 12 26.
Artículo en Inglés | MEDLINE | ID: mdl-38039128

RESUMEN

Upon proinflammatory challenges, endothelial cell surface presentation of the leukocyte receptor P-selectin, together with the stabilizing co-factor CD63, is needed for leukocyte capture and is mediated via demand-driven exocytosis from the Weibel-Palade bodies that fuse with the plasma membrane. We report that neutrophil recruitment to activated endothelium is significantly reduced in mice deficient for the endolysosomal cation channel TPC2 and in human primary endothelial cells with pharmacological TPC2 block. We observe less CD63 signal in whole-mount stainings of proinflammatory-activated cremaster muscles from TPC2 knockout mice. We find that TPC2 is activated and needed to ensure the transfer of CD63 from endolysosomes via Weibel-Palade bodies to the plasma membrane to retain P-selectin on the cell surface of human primary endothelial cells. Our findings establish TPC2 as a key element to leukocyte interaction with the endothelium and a potential pharmacological target in the control of inflammatory leukocyte recruitment.


Asunto(s)
Selectina-P , Canales de Dos Poros , Ratones , Humanos , Animales , Selectina-P/metabolismo , Células Endoteliales/metabolismo , Cuerpos de Weibel-Palade/metabolismo , Adhesión Celular , Leucocitos/metabolismo , Endotelio Vascular/metabolismo
12.
Mutagenesis ; 27(5): 589-97, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22610669

RESUMEN

We have developed and validated a sandwich chemiluminescence immunoassay (SCIA) which measures polycyclic aromatic hydrocarbon (PAH)-DNA adducts combining high throughput and adequate sensitivity, appropriate for evaluation of adduct levels in human population studies. Fragmented DNA is incubated with rabbit antiserum elicited against DNA modified with r7,t8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) and subsequently trapped by goat anti-rabbit IgG bound to a solid surface. Anti-single-stranded (ss) DNA antibodies binds in a quantity proportional to the adduct levels and is detected by chemiluminescence. The BPDE-DNA SCIA has a limit of detection of 3 adducts per 10(9) nucleotides with 5 µg DNA per well. We have validated the BPDE-DNA SCIA using DNA modified in vitro, DNA from benzo[a]pyrene (BP)-exposed cultured cells and mice. The levels of adduct measured by SCIA were lower (30-60%) than levels of bulky DNA adducts measured in the same samples by (32)P-postlabelling. The BPDE-DNA SCIA also detected adducts produced in vivo by PAHs other than BP. When blood DNA samples from maternal/infant pairs were assayed by BPDE-DNA SCIA, the adduct levels obtained were significantly correlated. However, there was no correlation between (32)P-postlabelling and SCIA values for the same samples. The SCIA can be extended to any DNA adduct and is expected to provide, when fully automated, a valuable high-throughput approach in large-scale population studies.


Asunto(s)
7,8-Dihidro-7,8-dihidroxibenzo(a)pireno 9,10-óxido/química , Aductos de ADN/química , Ensayo de Inmunoadsorción Enzimática/métodos , Mediciones Luminiscentes/métodos , Hidrocarburos Policíclicos Aromáticos/química , Adulto , Animales , Femenino , Células Hep G2 , Humanos , Recién Nacido , Leucocitos Mononucleares , Células MCF-7 , Masculino , Ratones , Estándares de Referencia , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Coloración y Etiquetado/métodos
13.
Adv Sci (Weinh) ; 9(36): e2201505, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36310133

RESUMEN

Mechanisms keeping leukocytes distant of local inflammatory processes in a resting state despite systemic release of inflammatory triggers are a pivotal requirement for avoidance of overwhelming inflammation but are ill defined. Dimers of the alarmin S100A8/S100A9 activate Toll-like receptor-4 (TLR4) but extracellular calcium concentrations induce S100A8/S100A9-tetramers preventing TLR4-binding and limiting their inflammatory activity. So far, only antimicrobial functions of released S100A8/S100A9-tetramers (calprotectin) are described. It is demonstrated that extracellular S100A8/S100A9 tetramers significantly dampen monocyte dynamics as adhesion, migration, and traction force generation in vitro and immigration of monocytes in a cutaneous granuloma model and inflammatory activity in a model of irritant contact dermatitis in vivo. Interestingly, these effects are not mediated by the well-known binding of S100A8/S100A9-dimers to TLR-4 but specifically mediated by S100A8/S100A9-tetramer interaction with CD69. Thus, the quaternary structure of these S100-proteins determines distinct and even antagonistic effects mediated by different receptors. As S100A8/S100A9 are released primarily as dimers and subsequently associate to tetramers in the high extracellular calcium milieu, the same molecules promote inflammation locally (S100-dimer/TLR4) but simultaneously protect the wider environment from overwhelming inflammation (S100-tetramer/CD69).


Asunto(s)
Monocitos , Receptor Toll-Like 4 , Humanos , Receptor Toll-Like 4/metabolismo , Calcio/metabolismo , Calgranulina B/metabolismo , Calgranulina A/química , Calgranulina A/metabolismo , Inflamación/metabolismo
14.
Mutagenesis ; 26(4): 523-7, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21454326

RESUMEN

Tobacco smoke contains many alkylating agents that can react with DNA to produce O(4)-ethylthymidine (O(4)-etT) and several other types of promutagenic base modifications. Our aims were (i) to confirm results of a pilot study (Godschalk, R., Nair, J., Schooten, F. J., Risch, A., Drings, P., Kayser, K., Dienemann, H. and Bartsch, H. (2002) Comparison of multiple DNA adduct types in tumor adjacent human lung tissue: effect of cigarette smoking. Carcinogenesis, 23, 2081-2086) on the formation of O(4)-etT in smokers' lung; (ii) to explore associations between levels of O(4)-etT and smoking status and (iii) to investigate whether a correlation exists between levels of O(4)-etT and bulky (polycyclic aromatic hydrocarbons-derived) DNA adducts. Archived DNA samples originated from histologically normal peripheral lung tissues of 64 Hungarian lung cancer patients, who underwent lung resection. O(4)-etT was determined by an immunoenriched (32)P-postlabelling-high-performance liquid chromatography method. Levels of bulky DNA adducts were determined by the nuclease P1 adduct-enriched (32)P-postlabelling. O(4)-etT levels ranged from 0.01 to 3.91 adducts/10(8) thymidines. In the combined group of subjects who smoked until surgery or gave up smoking at most 1 year before it, the mean level of O(4)-etT was 1.7-fold (P = 0.015) and of bulky DNA adducts 2.2-fold (P < 0.0001) higher than in long-term ex-smokers (LES) and never-smokers (NS) combined. We found no significant correlation between the individual levels of the two DNA adduct types. No dose-response was detected between O(4)-etT formation and smoking dose. In one-third of LES, O(4)-etT levels were above the 2.0-fold mean level of adducts found in NS, indicating its high persistence. Our results confirm the smoking-related formation of O(4)-etT in human lung DNA that should be explored as biomarker. Its long persistence in target tissue implicates a role of this potentially miscoding lesion in tobacco smoking-associated cancers.


Asunto(s)
Aductos de ADN/metabolismo , Pulmón/metabolismo , Fumar/metabolismo , Timidina/análogos & derivados , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Timidina/química , Timidina/metabolismo
15.
Mutat Res ; 721(1): 95-100, 2011 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-21237286

RESUMEN

Bulky DNA adducts are widely used as biomarkers of human exposure to complex mixtures of environmental genotoxicants including polycyclic aromatic hydrocarbons. The 32P-postlabelling method is highly sensitive for the detection of bulky DNA adducts, but its relatively low throughput poses limits to its use in large-scale molecular epidemiological studies. The objectives of this study were to compare the impact of DNA-sample preparation with a commercial DNA-isolation kit or with the classical phenol-extraction procedure on the measurement of bulky DNA adducts by 32P-postlabelling, and to increase the throughput of the 32P-postlabelling method--whilst maintaining radio-safety--by reducing the radioisotope requirement per sample. The test DNA samples were prepared from MCF-7 cells treated with benzo[a]pyrene and from human peripheral blood lymphocytes, buffy coat, and peripheral lung tissue. The modified 32P-postlabelling procedure involved an evaporation-to-dryness step after the enzymatic digestions of the DNA, and radio-labelling with a reduced amount of [γ-32P]ATP substrate in a reduced reaction volume compared with the regular method. Higher levels of DNA adducts were measured in the MCF-7 cells and in the lung-tissue samples after isolation with the kit than after solvent extraction. A seven-fold higher level of adducts was detected in the buffy-coat DNA samples isolated with the kit than with the phenol extraction procedure (p<0.001). Reduction of the amount of [γ-32P]ATP from 50 µCi to 25 µCi (>6000 Ci/mmol specific radioactivity) per sample in the modified 32P-postlabelling procedure was generally applicable without loss of adduct recovery for all test samples prepared with both DNA isolation methods. The difference between the bulky DNA-adduct levels resulting from the two DNA-isolation procedures requires further systematic investigation. The modified 32P-postlabelling procedure allows a 50% reduction of radioisotope requirement per sample, which facilitates increased throughput of the assay whilst maintaining radio-safety.


Asunto(s)
Aductos de ADN/análisis , ADN/aislamiento & purificación , Marcaje Isotópico/métodos , Radioisótopos de Fósforo , Línea Celular , Humanos , Pulmón , Linfocitos , Fenol , Juego de Reactivos para Diagnóstico
16.
Adv Sci (Weinh) ; 8(18): e2100694, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34278745

RESUMEN

The transport of membrane impermeable compounds into cells is a prerequisite for the efficient cellular delivery of hydrophilic and amphiphilic compounds and drugs. Transport into the cell's cytosolic compartment should ideally be controllable and it should involve biologically compatible and degradable vehicles. Addressing these challenges, nanocontainers based on cyclodextrin amphiphiles that are stabilized by a biodegradable peptide shell are developed and their potential to deliver fluorescently labeled cargo into human cells is analyzed. Host-guest mediated self-assembly of a thiol-containing short peptide or a cystamine-cross-linked polypeptide shell on cyclodextrin vesicles produce short peptide-shelled (SPSVss ) or polypeptide-shelled vesicles (PPSVss ), respectively, with redox-responsive and biodegradable features. Whereas SPSVss are permeable and less stable, PPSVss effectively encapsulate cargo and show a strictly regulated release of membrane impermeable cargo triggered by either reducing conditions or peptidase treatment. Live cell experiments reveal that the novel PPSVSS are readily internalized by primary human endothelial cells (human umbilical vein endothelial cells) and cervical cancer cells and that the reductive microenvironment of the cells' endosomes trigger release of the hydrophilic cargo into the cytosol. Thus, PPSVSS represent a highly efficient, biodegradable, and tunable system for overcoming the plasma membrane as a natural barrier for membrane-impermeable cargo.


Asunto(s)
Ciclodextrinas/metabolismo , Sistemas de Liberación de Medicamentos/métodos , Liberación de Fármacos , Células Endoteliales/metabolismo , Interacciones Hidrofóbicas e Hidrofílicas , Péptidos/metabolismo , Humanos , Nanopartículas/metabolismo
17.
Cells ; 9(5)2020 05 08.
Artículo en Inglés | MEDLINE | ID: mdl-32397265

RESUMEN

Annexin A2 (AnxA2) is a cytosolic Ca2+ regulated membrane binding protein that can induce lipid domain formation and plays a role in exocytosis and endocytosis. To better understand the mode of annexin-membrane interaction, we analyzed membrane-bound AnxA2 assemblies by employing a novel 3-armed chemical crosslinker and specific AnxA2 mutant proteins. Our data show that AnxA2 forms crosslinkable oligomers upon binding to membranes containing negatively charged phospholipids. AnxA2 mutants with amino acid substitutions in residues predicted to be involved in lateral protein-protein interaction show compromised oligomer formation, albeit still being capable of binding to negatively charged membranes in the presence of Ca2+. These results suggest that lateral protein-protein interactions are involved in the formation of AnxA2 clusters on a biological membrane.


Asunto(s)
Anexina A2/metabolismo , Membrana Celular/metabolismo , Multimerización de Proteína , Alquilación , Biotina/metabolismo , Reactivos de Enlaces Cruzados/química , Humanos , Modelos Moleculares , Proteínas Mutantes/metabolismo , Unión Proteica
18.
Mutagenesis ; 24(6): 475-80, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19643813

RESUMEN

Lung cancer rate in Hungary is one of the highest in the world among men and also very high among women, for reasons not clearly understood yet. The aim of the study was to explore characteristics of DNA damage and TP53 gene mutations in lung cancer from Hungary. Tissue samples from 104 lung resections for lung cancer patients, both men and women, operated on for non-small cell lung cancer, specifically, primary squamous cell carcinoma or adenocarcinoma were studied. Of the cases, 37% smoked up to the surgery, 24% stopped smoking within 1 year before the surgery, 26% stopped smoking more than a year before the surgery and 13% never smoked. TP53 mutations were detected by denaturant gradient gel electrophoresis, automated capillary electrophoresis single-strand conformation polymorphism and sequencing. Bulky DNA adduct levels were determined by (32)P-post-labelling in non-tumorous lung tissue. In total, 45% (47/104) of the cases carried TP53 mutation. The prevalence of TP53 mutations was statistically significantly associated with duration of smoking, tumour histology and gender. Smokers had approximately twice as high bulky adduct level as the combined group of former- and never-smokers (10.9 +/- 6.5 versus 5.5 +/- 3.4 adducts/10(8) nucleotides). The common base change G --> T transversion (8/43; 19%) was detected exclusively in smokers. For the first time, we demonstrate that most carriers of G --> T transversions had also a high level of bulky DNA adducts in their non-tumourous lung tissue. Our study provides evidence for a high burden of molecular alterations occurring concurrently in the lung of lung cancer patients.


Asunto(s)
Adenocarcinoma/genética , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Células Escamosas/genética , Aductos de ADN , Neoplasias Pulmonares/genética , Mutación , Fumar/efectos adversos , Proteína p53 Supresora de Tumor/genética , Adenocarcinoma/etiología , Adulto , Anciano , Carcinoma de Pulmón de Células no Pequeñas/etiología , Carcinoma de Células Escamosas/etiología , Femenino , Humanos , Hungría , Neoplasias Pulmonares/etiología , Masculino , Persona de Mediana Edad
19.
BMJ Open Gastroenterol ; 6(1): e000264, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31139423

RESUMEN

INTRODUCTION: Numerous indications require regular upper gastrointestinal endoscopy (oesophagogastroduodenoscopy; EGD) in outpatients. In most cases, peroral gastroscopy is performed. The aim of this study was to evaluate the need of transnasal gastroscopy (nEGD) in outpatients. METHODS: A questionnaire was used to assess patients' preferred choice of method, previous experience with EGD, psychological aspects and sociodemographic data. Furthermore, patient satisfaction with and potentially perceived discomfort during the examination as well as preference for a method in regard to future examinations was evaluated. RESULTS: From September 2016 to March 2017, a total of 283 outpatients at endoscopy of the University Hospital of Leipzig were approached to participate in the study. 196 patients were eligible, of whom 116 (60%) chose nEGD. For 87 patients (87/283, 31%) nEGD had to be excluded for medical reasons. The average age in the total sample was 53 (±17) years. 147 (77%) have had previous experience with peroral EGD (oEGD). Of the nEGD examined patients 83% were fairly up to extremely satisfied with the procedure. Satisfaction significantly predicted the choice of future EGD examinations. Nasal pain experienced during nEGDs was associated with rejection of nEGD in further EGD examinations (p<0.01). Patients who did choose a specific procedure were more likely to select the same procedure as their future preference (χ²= 73.6, df=1, p<0.001); this preference was unaffected by the procedure that had been chosen previously (reselecting nEGD: 84%, oEGD: 89%, p=0.874). CONCLUSION: nEGD without sedation is a viable alternative. Patient satisfaction with nEGD is high, and reselection rate for nEGD is similar to that for oEGD. As a result of this study nEGD is now offered as a routine procedure at the University of Leipzig. TRIAL REGISTRATION NUMBER: NCT03663491.

20.
Adv Sci (Weinh) ; 6(24): 1901935, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31871866

RESUMEN

The specific transport of amphiphilic compounds such as fluorescently labeled phospholipids into cells is a prerequisite for the analysis of highly dynamic cellular processes involving these molecules, e.g., the intracellular distribution and metabolism of phospholipids. However, cellular delivery remains a challenge as it should not affect the physiological integrity and morphology of the cell membrane. To address this, polymer nanocontainers based on redox-responsive cyclodextrin (CD) amphiphiles are prepared, and their potential to deliver fluorescently labeled phospholipids to intracellular membrane compartments is analyzed. It is shown that mixtures of reductively degradable cyclodextrin amphiphiles and different phospholipids form liposome-like vesicles (CD-lipid vesicles, CSSLV) with a homogeneous distribution of each lipid. Host-guest-mediated self-assembly of a cystamine-crosslinked polymer shell on these CSSLV produces polymer-shelled liposomal vesicles (PSSCSSLV) with the unique feature of a redox-sensitive CSSLV core and reductively degradable polymer shell. PSSCSSLV show high stability and a redox-sensitive release of the amphiphilic cargo. Live cell experiments reveal that the novel PSSCSSLV are readily internalized by primary human endothelial cells and that the reductive microenvironment of the cells' endosomes triggers the release of the amphiphilic cargo into the cytosol. Thus, PSSCSSLV represent a highly efficient system to transport lipid-like amphiphilic cargo into the intracellular environment.

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