Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
1.
Development ; 150(14)2023 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-37350382

RESUMO

Retinoic acid (RA) is the proposed mammalian 'meiosis inducing substance'. However, evidence for this role comes from studies in the fetal ovary, where germ cell differentiation and meiotic initiation are temporally inseparable. In the postnatal testis, these events are separated by more than 1 week. Exploiting this difference, we discovered that, although RA is required for spermatogonial differentiation, it is dispensable for the subsequent initiation, progression and completion of meiosis. Indeed, in the absence of RA, the meiotic transcriptome program in both differentiating spermatogonia and spermatocytes entering meiosis was largely unaffected. Instead, transcripts encoding factors required during spermiogenesis were aberrant during preleptonema, and the subsequent spermatid morphogenesis program was disrupted such that no sperm were produced. Taken together, these data reveal a RA-independent model for male meiotic initiation.


Assuntos
Testículo , Tretinoína , Animais , Feminino , Masculino , Tretinoína/farmacologia , Espermatogênese/genética , Espermatogônias , Espermatozoides , Meiose/genética , Mamíferos
2.
Methods Mol Biol ; 2656: 37-70, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37249866

RESUMO

Robust methods have been developed that leverage next-generation sequencing (NGS) to measure abundance of all mRNAs (RNA-seq) in samples as small as individual cells in order to study the testicular transcriptome in mammals. In this chapter, we present robust options for implementing bioinformatics workflows for the analysis of bulk RNA-seq from aggregate samples of hundreds to millions of cells and single-cell RNA-seq from individual cells. We also provide detailed protocols for using the R packages DESeq2 and Seurat, important parameters for successful implementation, and considerations for drawing conclusions from the results.


Assuntos
Análise da Expressão Gênica de Célula Única , Espermatogônias , Masculino , Animais , Transcriptoma , Testículo , RNA-Seq , Análise de Célula Única/métodos , Análise de Sequência de RNA/métodos , Perfilação da Expressão Gênica/métodos , Mamíferos
3.
Int J Mol Sci ; 24(5)2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36902187

RESUMO

Antineoplastic treatments for cancer and other non-malignant disorders can result in long-term or permanent male infertility by ablating spermatogonial stem cells (SSCs). SSC transplantation using testicular tissue harvested before a sterilizing treatment is a promising approach for restoring male fertility in these cases, but a lack of exclusive biomarkers to unequivocally identify prepubertal SSCs limits their therapeutic potential. To address this, we performed single-cell RNA-seq on testis cells from immature baboons and macaques and compared these cells with published data from prepubertal human testis cells and functionally-defined mouse SSCs. While we found discrete groups of human spermatogonia, baboon and rhesus spermatogonia appeared less heterogenous. A cross-species analysis revealed cell types analogous to human SSCs in baboon and rhesus germ cells, but a comparison with mouse SSCs revealed significant differences with primate SSCs. Primate-specific SSC genes were enriched for components and regulators of the actin cytoskeleton and participate in cell-adhesion, which may explain why the culture conditions for rodent SSCs are not appropriate for primate SSCs. Furthermore, correlating the molecular definitions of human SSC, progenitor and differentiating spermatogonia with the histological definitions of Adark/Apale spermatogonia indicates that both SSCs and progenitor spermatogonia are Adark, while Apale spermatogonia appear biased towards differentiation. These results resolve the molecular identity of prepubertal human SSCs, define novel pathways that could be leveraged for advancing their selection and propagation in vitro, and confirm that the human SSC pool resides entirely within Adark spermatogonia.


Assuntos
Células-Tronco Germinativas Adultas , Espermatogônias , Humanos , Masculino , Animais , Camundongos , Espermatogônias/metabolismo , Testículo , Espermatogênese , Transcriptoma , Primatas
4.
Acta Oncol ; 61(4): 403-408, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34913815

RESUMO

PURPOSE: It is essential to evaluate the risk of occult lymph node (LN) disease in early-stage non-small cell lung cancer (NSCLC), especially because delivering stereotactic ablative radiotherapy (SABR) assumes no occult spread. This study was designed to assist clinicians in roughly quantifying this risk for cN0 NSCLC. METHODS: The National Cancer Data Base was queried for cN0 cM0 lung squamous cell or adenocarcinoma who underwent surgery and LN dissection without neoadjuvant therapy. Statistics included multivariable logistic regression to evaluate factors associated with pN + disease. RESULTS: 109,964 patients were included. For tumors with size ≤1.0, 1.1-2.0, 2.1-3.0, 3.1-4.0, 4.1-5.0, 5.1-6.0, 6.1-7.0, and >7.0 cm, the pN + rate was 4.4, 7.7, 12.9, 18.0, 20.2, 22.5, 24.4, and 26.4%, respectively. When examining patients with more complete LN dissections (defined as removal of at least 10 LNs), the respective values were 6.6, 11.5, 17.6, 25.3, 26.8, 29.7, 30.7, and 31.6%. Moderately-poorly differentiated disease and adenocarcinomas were associated with a higher rate of pN + disease (p < .001 for both). For every cm increase in tumor size, the relative occult nodal risk increased by 10-14% (p < .001). For every elapsed day from initial diagnosis, the relative risk increased by ∼1% (p < .001). Graphs with best-fit lines were created based on tumor size, histology, and differentiation to aid physicians in estimating the pN + risk. CONCLUSIONS: This nationwide study can allow clinicians to roughly estimate the rate of occult LN disease in cN0 NSCLC. These data can also assist in guiding enrollment on randomized trials of SABR ± immunotherapy, individualizing follow-up imaging surveillance, and patient counseling to avoid post-diagnosis delays.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Carcinoma Pulmonar de Células não Pequenas/patologia , Humanos , Neoplasias Pulmonares/patologia , Excisão de Linfonodo , Linfonodos/patologia , Linfonodos/cirurgia , Metástase Linfática/patologia , Estadiamento de Neoplasias , Estudos Retrospectivos
6.
Radiother Oncol ; 162: 52-59, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34214615

RESUMO

PURPOSE: The utility of post-mastectomy radiotherapy (PMRT) in women with a nodal complete response (CRn) to neoadjuvant chemotherapy (NAC) is unknown. The NSABP B-51 trial is evaluating this question, but has not reported results thus far. Therefore, we sought to answer this question with the National Cancer Database. METHODS: The National Cancer Database was queried for women with cT1-4N1-3M0 breast cancer who had undergone NAC and were ypN0 upon mastectomy. Statistics included multivariable logistic regression, Kaplan-Meier overall survival (OS) analysis, Cox proportional hazards modeling, and construction of forest plots. RESULTS: Of 14,690 women, 10,092 (69%) underwent adjuvant PMRT and 4598 (31%) did not. The median follow-up was 55.6 months. In all patients, the 10-year OS was 76.3% for PMRT and 78.6% without (p = 0.412). There were no notable effects of PMRT on OS based on age or the axillary management (number of nodes removed). Specifically, in the NSABP B-51 population of cT1-3 cN1 patients, the 10-year OS was 82.6% for PMRT and 80.0% without (p = 0.250). PMRT benefitted women with increasing cT stage (i.e. cT3-4), increasing ypT stages (with the exception of ypT4 potentially owing to small sample sizes), and cN3 cases (p < 0.05 for all). CONCLUSIONS: In the absence of published results from NSABP B-51, this assessment of over 14,000 women from a contemporary US database revealed that PMRT may be most useful for a "moderately-high" risk group - women with more advanced primary and/or nodal disease at diagnosis, yet with tumor biology favorable enough that the disease does not progress or remain stable after NAC. The OS findings notwithstanding, this study cannot exclude potential differences between groups in recurrence-free survival, which is the primary endpoint of NSABP B-51, While the results of the NSABP B-51 will confirm optimal management for patients with limited nodal disease having a CRn following NAC, the present results suggest PMRT should remain the standard of care for more advanced disease than NSABP B-51 eligibility criteria.


Assuntos
Neoplasias da Mama , Terapia Neoadjuvante , Neoplasias da Mama/patologia , Quimioterapia Adjuvante , Feminino , Humanos , Mastectomia , Estadiamento de Neoplasias , Radioterapia Adjuvante , Estudos Retrospectivos
7.
Neoplasia ; 22(10): 497-510, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32896760

RESUMO

Glioblastoma (GBM) represents the most aggressive malignancy of the central nervous system. Increased expression of Angiotensin II Receptor Type 1 (AGTR1) has been associated with proliferative and infiltrative properties of glioma cells. However, the underlying mechanism of AGTR1 upregulation in GBM is still unexplored. To understand the post-transcriptional regulation of AGTR1 in GBM, we screened 3'untranslated region (3'UTR) of AGTR1 for putative miRNA binding by using prediction algorithms. Interestingly, miR-155 showed conserved binding on the 3'UTR of AGTR1, subsequently confirmed by luciferase reporter assay. Furthermore, miR-155 overexpressing GBM cells show decrease in AGTR1 expression accompanied with reduced cell proliferation, invasion, foci formation and anchorage-independent growth. Strikingly, immunodeficient mice implanted with stable miR-155 overexpressing SNB19 cells show negligible tumor growth. Notably, miR-155 attenuates NF-κB signaling downstream of AGTR1 leading to reduced CXCR4 as well as AGTR1 levels. Mechanistically, miR-155 mitigates AGTR1-mediated angiogenesis, epithelial-to-mesenchymal transition, stemness, and MAPK signaling. Similar effects were observed by using pharmacological inhibitor of IκB Kinase (IKK) complex in multiple cell-based assays. Taken together, we established that miRNA-155 post-transcriptionally regulates AGTR1 expression, abrogates AGTR1/NF-κB/CXCR4 signaling axis and elicits pleiotropic anticancer effects in GBM. This study opens new avenues for using IKK inhibitors and miRNA-155 replacement therapies for the treatment of AGTR1-positive malignancies.


Assuntos
Neoplasias Encefálicas/patologia , Glioblastoma/patologia , MicroRNAs/genética , NF-kappa B/metabolismo , Receptor Tipo 1 de Angiotensina/metabolismo , Receptores CXCR4/metabolismo , Animais , Apoptose , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Movimento Celular , Proliferação de Células , Feminino , Regulação Neoplásica da Expressão Gênica , Glioblastoma/genética , Glioblastoma/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , NF-kappa B/genética , Receptor Tipo 1 de Angiotensina/genética , Receptores CXCR4/genética , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
8.
Int J Mycobacteriol ; 9(2): 209-211, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32474546

RESUMO

Background: Mycobacterium leprae is a noncultivable mycobacteria, and diagnosis of the disease is based on its clinical and histopathological characteristics and finding the bacteria in skin scrapings and in biopsies taken from the patients. The aim of this study was to shed light on the clinical classification (based on the number of skin lesions) used extensively in the field where patients classified as paucibacillary (PB) were positive on skin smears and histopathology leading to treatment failure and drug resistance. Methods: In this study, we enrolled untreated 62 leprosy patients with 1-5 skin lesions and did a detailed bacterio-histopathological analysis by slit-skin smears (SSSs) and histopathology. Results: Of 62 patients analyzed, 15 patients came out to be multibacillary (MB) and 47 were PB by SSS and histopathology. Conclusion: The findings of the present study showed that the WHO classification of leprosy based on the number of lesions seems to be inappropriate as it considers a number of MB lesions as PB only, thus misleading the treatment strategies. Hence, it is essential that a comprehensive clinicobacteriological assessment of leprosy cases should be done to ensure the appropriate bacillary status and guiding the appropriate treatment strategy.


Assuntos
Hanseníase Multibacilar/microbiologia , Hanseníase Paucibacilar/microbiologia , Dermatopatias/microbiologia , Dermatopatias/patologia , Adolescente , Adulto , Idoso , Biópsia , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Hanseníase Multibacilar/diagnóstico , Hanseníase Paucibacilar/diagnóstico , Masculino , Pessoa de Meia-Idade , Mycobacterium leprae/patogenicidade , Adulto Jovem
9.
Nanomaterials (Basel) ; 10(5)2020 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-32397078

RESUMO

The determination of reaction pathways and identification of products of pollutants degradation is central to photocatalytic environmental remediation. This work focuses on the photocatalytic degradation of the herbicide Imazapyr (2-(4-methyl-5-oxo-4-propan-2-yl-1H-imidazol-2-yl) pyridine-3-carboxylic acid) under UV-Vis and visible-only irradiation of aqueous suspensions of CaxMnOy-TiO2, and on the identification of the corresponding degradation pathways and reaction intermediates. CaxMnOy-TiO2 was formed by mixing CaxMnOy and TiO2 by mechanical grinding followed by annealing at 500 °C. A complete structural characterization of CaxMnOy-TiO2 was carried out. The photocatalytic activity of the hetero-nanostructures was determined using phenol and Imazapyr herbicide as model pollutants in a stirred tank reactor under UV-Vis and visible-only irradiation. Using equivalent loadings, CaxMnOy-TiO2 showed a higher rate (10.6 µM·h-1) as compared to unmodified TiO2 (7.4 µM·h-1) for Imazapyr degradation under UV-Vis irradiation. The mineralization rate was 4.07 µM·h-1 for CaxMnOy-TiO2 and 1.21 µM·h-1 for TiO2. In the CaxMnOy-TiO2 system, the concentration of intermediate products reached a maximum at 180 min of irradiation that then decreased to a half in 120 min. For unmodified TiO2, the intermediates continuously increased with irradiation time with no decrease observed in their concentration. The enhanced efficiency of the CaxMnOy-TiO2 for the complete degradation of the Imazapyr and intermediates is attributed to an increased adsorption of polar species on the surface of CaxMnOy. Based on LC-MS, photocatalytic degradation pathways for Imazapyr under UV-Vis irradiation have been proposed. Some photocatalytic degradation was obtained under visible-only irradiation for CaxMnOy-TiO2. Hydroxyl radicals were found to be main reactive oxygen species responsible for the photocatalytic degradation through radical scavenger investigations.

10.
Sci Rep ; 10(1): 3224, 2020 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-32081894

RESUMO

P-glycoprotein (Pgp) pumps an array of hydrophobic compounds out of cells, and has major roles in drug pharmacokinetics and cancer multidrug resistance. Yet, polyspecific drug binding and ATP hydrolysis-driven drug export in Pgp are poorly understood. Fluorescence spectroscopy using tryptophans (Trp) inserted at strategic positions is an important tool to study ligand binding. In Pgp, this method will require removal of 11 endogenous Trps, including highly conserved Trps that may be important for function, protein-lipid interactions, and/or protein stability. Here, we developed a directed evolutionary approach to first replace all eight transmembrane Trps and select for transport-active mutants in Saccharomyces cerevisiae. Surprisingly, many Trp positions contained non-conservative substitutions that supported in vivo activity, and were preferred over aromatic amino acids. The most active construct, W(3Cyto), served for directed evolution of the three cytoplasmic Trps, where two positions revealed strong functional bias towards tyrosine. W(3Cyto) and Trp-less Pgp retained wild-type-like protein expression, localization and transport function, and purified proteins retained drug stimulation of ATP hydrolysis and drug binding affinities. The data indicate preferred Trp substitutions specific to the local context, often dictated by protein structural requirements and/or membrane lipid interactions, and these new insights will offer guidance for membrane protein engineering.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/química , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Evolução Molecular Direcionada , Mutação , Triptofano/química , Adenosina Trifosfatases/química , Dicroísmo Circular , Cristalografia por Raios X , Citoplasma/química , Detergentes , Escherichia coli , Biblioteca Gênica , Humanos , Cinética , Ligantes , Lipídeos/química , Reação em Cadeia da Polimerase , Conformação Proteica , Saccharomyces cerevisiae
11.
Development ; 146(12)2019 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-31023878

RESUMO

In the mammalian testis, sustained spermatogenesis relies on spermatogonial stem cells (SSCs); their progeny either remain as stem cells (self-renewal) or proliferate and differentiate to enter meiosis in response to retinoic acid (RA). Here, we sought to uncover elusive mechanisms regulating a key switch fundamental to spermatogonial fate: the capacity of spermatogonia to respond to RA. Using the developing mouse testis as a model, we found that spermatogonia and precursor prospermatogonia exhibit a heterogeneous capacity to respond to RA with at least two underlying causes. First, progenitor spermatogonia are prevented from responding to RA by catabolic activity of cytochrome P450 family 26 enzymes. Second, a smaller subset of undifferentiated spermatogonia enriched for SSCs exhibit catabolism-independent RA insensitivity. Moreover, for the first time, we observed that precursor prospermatogonia are heterogeneous and comprise subpopulations that exhibit the same differential RA responsiveness found in neonatal spermatogonia. We propose a novel model by which mammalian prospermatogonial and spermatogonial fates are regulated by their intrinsic capacity to respond (or not) to the differentiation signal provided by RA before, and concurrent with, the initiation of spermatogenesis.


Assuntos
Regulação da Expressão Gênica , Espermatogênese , Espermatogônias/citologia , Células-Tronco/citologia , Testículo/crescimento & desenvolvimento , Tretinoína/metabolismo , Animais , Diferenciação Celular , Linhagem da Célula , Família 26 do Citocromo P450/metabolismo , Genômica , Proteínas de Fluorescência Verde/metabolismo , Masculino , Meiose , Camundongos , Células de Sertoli/citologia , Transdução de Sinais , Testículo/embriologia
12.
Cell Rep ; 25(6): 1650-1667.e8, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30404016

RESUMO

Spermatogenesis is a complex and dynamic cellular differentiation process critical to male reproduction and sustained by spermatogonial stem cells (SSCs). Although patterns of gene expression have been described for aggregates of certain spermatogenic cell types, the full continuum of gene expression patterns underlying ongoing spermatogenesis in steady state was previously unclear. Here, we catalog single-cell transcriptomes for >62,000 individual spermatogenic cells from immature (postnatal day 6) and adult male mice and adult men. This allowed us to resolve SSC and progenitor spermatogonia, elucidate the full range of gene expression changes during male meiosis and spermiogenesis, and derive unique gene expression signatures for multiple mouse and human spermatogenic cell types and/or subtypes. These transcriptome datasets provide an information-rich resource for studies of SSCs, male meiosis, testicular cancer, male infertility, or contraceptive development, as well as a gene expression roadmap to be emulated in efforts to achieve spermatogenesis in vitro.


Assuntos
Mamíferos/genética , Análise de Célula Única , Espermátides/citologia , Espermatogênese/genética , Espermatogônias/citologia , Transcriptoma/genética , Adulto , Envelhecimento/genética , Animais , Diferenciação Celular , Regulação da Expressão Gênica no Desenvolvimento , Haploidia , Humanos , Masculino , Meiose , Camundongos Endogâmicos C57BL , Transdução de Sinais , Espermátides/metabolismo , Espermatogônias/metabolismo , Células-Tronco/citologia , Células-Tronco/metabolismo , Testículo/citologia
13.
Mater Sci Eng C Mater Biol Appl ; 90: 273-279, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29853092

RESUMO

In the present work, a comparative study was performed between single-walled carbon nanotubes and multi-walled carbon nanotubes coated gold printed circuit board electrodes for glucose detection. Various characterization techniques were demonstrated in order to compare the modified electrodes viz. cyclic voltammetry, electrochemical impedance spectroscopy and chrono-amperometry. Results revealed that single-walled carbon nanotubes outperformed multi-walled carbon nanotubes and proved to be a better sensing interface for glucose detection. The single-walled carbon nanotubes coated gold printed circuit board electrodes showed a wide linear sensing range (1 mM to 100 mM) with detection limit of 0.1 mM with response time of 5 s while multi-walled carbon nanotubes coated printed circuit board gold electrodes showed linear sensing range (1 mM to 100 mM) with detection limit of 0.1 mM with response time of 5 s. This work provided low cost sensors with enhanced sensitivity, fast response time and reliable results for glucose detection which increased the affordability of such tests in remote areas. In addition, the comparative results confirmed that single-walled carbon nanotubes modified electrodes can be exploited for better amplification signal as compared to multi-walled carbon nanotubes.


Assuntos
Técnicas Eletroquímicas/métodos , Ouro/química , Nanopartículas Metálicas/química , Nanotubos de Carbono/química , Eletrodos
14.
Transl Oncol ; 11(2): 233-242, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29413755

RESUMO

Renin angiotensin system (RAS) comprising Angiotensin converting enzyme (ACE), Angiotensin II (Ang II) and its receptor Angiotensin II receptor type I (AGTR1), plays a critical role in several diseases including cancer. A single nucleotide polymorphism (SNP) A1166C located in 3' untranslated region (UTR) of AGTR1 and an insertion/deletion (I/D) polymorphism present in intron 16 of ACE gene have been associated with many diseases, but their association with Breast cancer (BCa) is still debatable. Here, we for the first time investigated the association of these polymorphisms in a North Indian BCa cohort including 161 patients and 152 healthy women. The polymorphisms were evaluated by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) respectively. The association between these polymorphisms and BCa risk was estimated by calculating Odds Ratio (OR) and chi-square (χ2) test. The DD genotype/D allele of ACE (I/D) polymorphism and "AC and CC" genotype/C allele of AGTR1 (A1166C) polymorphism were associated with higher risk of BCa when evaluated independently. Furthermore, interaction analysis of "AC and CC" and DD genotype and combination of "C and D" alleles of both polymorphisms revealed significantly greater BCa risk than that observed independently. Conclusively, women harboring "AC or CC" genotype/C allele for AGTR1 (A1166C) polymorphism and DD genotype/D allele for ACE (I/D) polymorphisms have a predisposition to develop more aggressive disease with advanced staging and larger tumor size. Our study indicates importance of genetic screening based on these polymorphisms for women, who may have higher risk of BCa.

15.
J Biol Chem ; 292(50): 20412-20424, 2017 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-29018094

RESUMO

P-glycoprotein (Pgp) is an efflux pump important in multidrug resistance of cancer cells and in determining drug pharmacokinetics. Pgp is a prototype ATP-binding cassette transporter with two nucleotide-binding domains (NBDs) that bind and hydrolyze ATP. Conformational changes at the NBDs (the Pgp engines) lead to changes across Pgp transmembrane domains that result in substrate translocation. According to current alternating access models (substrate-binding pocket accessible only to one side of the membrane at a time), binding of ATP promotes NBD dimerization, resulting in external accessibility of the drug-binding site (outward-facing, closed NBD conformation), and ATP hydrolysis leads to dissociation of the NBDs with the subsequent return of the accessibility of the binding site to the cytoplasmic side (inward-facing, open NBD conformation). However, previous work has not investigated these events under near-physiological conditions in a lipid bilayer and in the presence of transport substrate. Here, we used luminescence resonance energy transfer (LRET) to measure the distances between the two Pgp NBDs. Pgp was labeled with LRET probes, reconstituted in lipid nanodiscs, and the distance between the NBDs was measured at 37 °C. In the presence of verapamil, a substrate that activates ATP hydrolysis, the NBDs of Pgp reconstituted in nanodiscs were never far apart during the hydrolysis cycle, and we never observed the NBD-NBD distances of tens of Å that have previously been reported. However, we found two main conformations that coexist in a dynamic equilibrium under all conditions studied. Our observations highlight the importance of performing studies of efflux pumps under near-physiological conditions, in a lipid bilayer, at 37 °C, and during substrate-stimulated hydrolysis.


Assuntos
Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Trifosfato de Adenosina/metabolismo , Bloqueadores dos Canais de Cálcio/metabolismo , Bicamadas Lipídicas/química , Modelos Moleculares , Verapamil/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP/química , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Trifosfato de Adenosina/química , Substituição de Aminoácidos , Animais , Sítios de Ligação , Transporte Biológico Ativo , Técnicas de Transferência de Energia por Ressonância de Bioluminescência , Bloqueadores dos Canais de Cálcio/química , Cisteína/química , Európio/química , Hidrólise , Camundongos , Mutação , Nanoestruturas/química , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Redobramento de Proteína , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Térbio/química , Verapamil/química
16.
Biochim Biophys Acta Biomembr ; 1859(1): 48-60, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27783926

RESUMO

Structural changes in mouse P-glycoprotein (Pgp) induced by thermal unfolding were studied by differential scanning calorimetry (DSC), circular dichroism and fluorescence spectroscopy to gain insight into the solution conformation(s) of this ABC transporter that may not be apparent from current crystal structures. DSC of reconstituted Pgp showed two thermal unfolding transitions in the absence of MgATP, suggesting that each transition involved the cooperative unfolding of two or more interacting structural domains. A low calorimetric unfolding enthalpy and minimal structural changes were observed, which are hallmarks of the thermal unfolding of α-helical membrane proteins, because generally only the extramembranous regions undergo significant unfolding. Nucleotide binding increased the unfolding temperature of both transitions to the same extent, suggesting that one nucleotide binding domain (NBD) unfolds with each transition. Combined with the results from the two isolated NBDs, we propose that each DSC transition represents the cooperative unfolding of one NBD and the two contacting intracellular loops. Further, the presence of two transitions in both apo and MgATP bound wild-type Pgp suggests the NBD-dimeric conformation is transient, and that Pgp resides predominantly in the crystallographically observed inward-facing conformation with NBDs separated, even under conditions supporting continuous MgATP hydrolysis. In contrast, DSC of the vanadate-trapped MgADP·Pgp complex and the MgATP-bound catalytically inactive mutant, E552A/E1197A, show an additional transition at much higher temperature, corresponding to the unfolding of the nucleotide-trapped NBD-dimeric outward-facing conformation. The collective results indicate a strong preference for an NBD dissociated, inward-facing conformation of Pgp.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/química , Difosfato de Adenosina/química , Trifosfato de Adenosina/química , Lipossomas Unilamelares/química , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Clonagem Molecular , Cristalografia por Raios X , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Humanos , Hidrólise , Cinética , Camundongos , Modelos Moleculares , Pichia/genética , Pichia/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice , Domínios e Motivos de Interação entre Proteínas , Desdobramento de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Homologia Estrutural de Proteína , Especificidade por Substrato , Termodinâmica , Lipossomas Unilamelares/metabolismo
17.
Biol Reprod ; 95(6): 117, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27733379

RESUMO

Precise separation of spermatogonial stem cells (SSCs) from progenitor spermatogonia that lack stem cell activity and are committed to differentiation remains a challenge. To distinguish between these spermatogonial subtypes, we identified genes that exhibited bimodal mRNA levels at the single-cell level among undifferentiated spermatogonia from Postnatal Day 6 mouse testes, including Tspan8, Epha2, and Pvr, each of which encode cell surface proteins useful for cell selection. Transplantation studies provided definitive evidence that a TSPAN8-high subpopulation is enriched for SSCs. RNA-seq analyses identified genes differentially expressed between TSPAN8-high and -low subpopulations that clustered into multiple biological pathways potentially involved in SSC renewal or differentiation, respectively. Methyl-seq analysis identified hypomethylated domains in the promoters of these genes in both subpopulations that colocalized with peaks of histone modifications defined by ChIP-seq analysis. Taken together, these results demonstrate functional heterogeneity among mouse undifferentiated spermatogonia and point to key biological characteristics that distinguish SSCs from progenitor spermatogonia.


Assuntos
Células-Tronco Germinativas Adultas/citologia , Testículo/citologia , Tetraspaninas/metabolismo , Células-Tronco Germinativas Adultas/metabolismo , Animais , Biomarcadores/metabolismo , Ciclo Celular/fisiologia , Perfilação da Expressão Gênica , Masculino , Camundongos , Receptor EphA2/genética , Receptor EphA2/metabolismo , Espermatogênese , Testículo/metabolismo , Tetraspaninas/genética
18.
J Clin Diagn Res ; 10(8): ZC95-9, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27656573

RESUMO

INTRODUCTION: Provision of oral health knowledge to the children by their teachers at the school level can prove to be more fruitful because it is the time period during which the children begin to learn the basic oral hygiene practices and are most prone to dental caries. AIM: This study was carried out to assess the effect of training school teachers on oral hygiene status of 8-10 years old government school children of Udaipur city, India. MATERIALS AND METHODS: A total of nine school teachers and 279, 8-10 year old school children from two government schools were included in the study. The questionnaire on oral health knowledge and practice contained 17 questions to evaluate the knowledge and practice of children towards oral hygiene before and after the teachers training program. Baseline and six months post training data on oral health knowledge and practice was obtained by the questionnaire method. Baseline and six months post training data on oral hygiene status was obtained by OHI-S Index. Statistical analysis was done using software SPSS 22, the test used were McNemar's test, paired t-test. RESULTS: Pre and post training data were compared and it was found that there was a significant improvement in oral health knowledge and practices of school teachers and children. Also oral hygiene status of school children was significantly improved after the program. CONCLUSION: Results of the present study suggest that experiential learning is an effective school based oral health education method for improvement of oral hygiene in primary school children.

19.
J Clin Diagn Res ; 9(10): ZC63-6, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26557620

RESUMO

BACKGROUND: As of late, natural contamination has stimulated as a reaction of mechanical and other human exercises. In India, with the expanding industrialization, numerous unsafe substances are utilized or are discharged amid generation as cleans, exhaust, vapours and gasses. These substances at last are blended in the earth and causes health hazards. OBJECTIVE: To determine concentration of fluoride in soils and vegetables grown in the vicinity of Zinc Smelter, Debari, Udaipur, Rajasthan. MATERIALS AND METHODS: Samples of vegetables and soil were collected from areas situated at 0, 1, 2, 5, and 10 km distance from the zinc smelter, Debari. Three samples of vegetables (i.e. Cabbage, Onion and Tomato) and 3 samples of soil {one sample from the upper layer of soil (i.e. 0 to 20 cm) and one from the deep layer (i.e. 20 - 40 cm)} at each distance were collected. The soil and vegetable samples were sealed in clean polythene bags and transported to the laboratory for analysis. One sample each of water and fertilizer from each distance were also collected. RESULTS: The mean fluoride concentration in the vegetables grown varied between 0.36 ± 0.69 to 0.71 ± 0.90 ppm. The fluoride concentration in fertilizer and water sample from various distances was found to be in the range of 1.4 - 1.5 ppm and 1.8 - 1.9 ppm respectively. CONCLUSION: The fluoride content of soil and vegetables was found to be higher in places near to the zinc smelter.

20.
Eur J Pharmacol ; 763(Pt B): 178-83, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-25981295

RESUMO

G-protein-coupled receptors (GPCRs) comprise a large family of cell-surface receptors, which have recently emerged as key players in tumorigenesis, angiogenesis and metastasis. In this review, we discussed our current understanding of the many roles played by GPCRs in general, and particularly Angiotensin II type I receptor (AGTR1), a member of the seven-transmembrane-spanning G-protein coupled receptor superfamily, and its significance in breast cancer progression and metastasis. We have also discussed different strategies for targeting AGTR1, and its ligand Angiotension II (Ang II), which might unravel unique opportunities for breast cancer prevention and treatment. For example, AGTR1 blockers (ARBs) which are already in clinical use for treating hypertension, merit further investigation as a therapeutic strategy for AGTR1-positive cancer patients and may have the potential to prevent Ang II-AGTR1 signalling mediated cancer pathogenesis and metastases.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Progressão da Doença , Receptores Acoplados a Proteínas G/metabolismo , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Humanos , Terapia de Alvo Molecular , Metástase Neoplásica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...