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1.
Cardiovasc Res ; 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38501595

RESUMO

AIMS: Prevention of human hypertension is an important challenge and has been achieved in experimental models. Brief treatment with renin-angiotensin system (RAS) inhibitors permanently reduces the genetic hypertension of the spontaneously hypertensive rat (SHR). The kidney is involved in this fascinating phenomenon, but relevant changes in gene expression are unknown. METHODS: In SHR, we studied the effect of treatment between 10 and 14 weeks of age with the angiotensin receptor blocker, losartan, or the angiotensin-converting enzyme (ACE) inhibitor, perindopril (with controls for non-specific effects of lowering BP) on differential RNA expression, DNA methylation and renin immunolabelling in the kidney at 20 weeks of age. RESULTS: RNA sequencing revealed a 6-fold increase in renin gene (Ren) expression during losartan treatment (P < 0.0001). Six weeks after losartan, arterial pressure remained lower (P = 0.006), yet kidney Ren showed reduced expression by 23% after losartan (P = 0.03) and by 43% after perindopril (P = 1.4 x 10-6) associated with increased DNA methylation (P = 0.04). Immunolabelling confirmed reduced cortical renin after earlier RAS blockade (P = 0.002). RNA sequencing identified differential expression of mRNAs, miRNAs and lncRNAs with evidence of networking and co-regulation. These included 13 candidate genes (Grhl1, Ammecr1l, Hs6st1, Nfil3, Fam221a, Lmo4, Adamts1, Cish, Hif3a, Bcl6, Rad54l2, Adap1, Dok4), the miRNA miR-145-3p and the lncRNA AC115371. Gene ontogeny analyses revealed that these networks were enriched with genes relevant to BP, RAS and the kidneys. CONCLUSIONS: Early RAS inhibition in SHR resets genetic pathways and networks resulting in a legacy of reduced Ren expression and BP persisting for a minimum of 6 weeks.

2.
Int J Mol Sci ; 24(17)2023 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-37685939

RESUMO

Atherosclerosis is characterized by the narrowing of the arterial lumen due to subendothelial lipid accumulation, with hypercholesterolemia being a major risk factor. Despite the recent advances in effective lipid-lowering therapies, atherosclerosis remains the leading cause of mortality globally, highlighting the need for additional therapeutic strategies. Accumulating evidence suggests that the sympathetic nervous system plays an important role in atherosclerosis. In this article, we reviewed the sympathetic innervation in the vasculature, norepinephrine synthesis and metabolism, sympathetic activity measurement, and common signaling pathways of sympathetic activation. The focus of this paper was to review the effectiveness of pharmacological antagonists or agonists of adrenoceptors (α1, α2, ß1, ß2, and ß3) and renal denervation on atherosclerosis. All five types of adrenoceptors are present in arterial blood vessels. α1 blockers inhibit atherosclerosis but increase the risk of heart failure while α2 agonism may protect against atherosclerosis and newer generations of ß blockers and ß3 agonists are promising therapies against atherosclerosis; however, new randomized controlled trials are warranted to investigate the effectiveness of these therapies in atherosclerosis inhibition and cardiovascular risk reduction in the future. The role of renal denervation in atherosclerosis inhibition in humans is yet to be established.


Assuntos
Aterosclerose , Insuficiência Cardíaca , Hipercolesterolemia , Humanos , Sistema Nervoso Simpático , Receptores Adrenérgicos , Lipídeos
3.
J Cell Biochem ; 124(3): 409-420, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36716229

RESUMO

Skeletal muscle atrophy is associated with increases in circulating glucocorticoid levels and insulin resistance. Zinc accumulates in atrophic muscle, but the relationship between atrophy, insulin resistance, and Zn2+ homeostasis remains unclear. In this study, the effect of the glucocorticoid dexamethasone (DEX) on insulin and Zn2+ homeostasis was explored. Treatment of differentiated C2C12 skeletal myotubes and 3T3-L1 adipocytes with DEX significantly increased mRNA expression of the metal-binding proteins Mt1 and 2 and altered energy storage as shown by the increased size of lipid droplets in 3T3-L1 cells. In C2C12 cells the total cellular Zn2+ was higher after DEX treatment, and in both C2C12 and 3T3-L1 adipocytes, free unbound Zn2+ was increased. Insulin treatment led to a gradual increase in free Zn2+ in C2C12 cells, and no significant change in DEX-treated cells such that concentrations were similar 10 min after insulin treatment. These data demonstrate that DEX disturbs Zn2+ homeostasis in muscle and fat cells. Further study of the molecular pathways involved to identify novel therapeutic targets for treatment of skeletal muscle atrophy is warranted.


Assuntos
Glucocorticoides , Resistência à Insulina , Camundongos , Animais , Glucocorticoides/farmacologia , Células 3T3-L1 , Fibras Musculares Esqueléticas , Atrofia Muscular/tratamento farmacológico , Insulina/farmacologia , Insulina/metabolismo , Obesidade/metabolismo , Dexametasona/farmacologia , Músculo Esquelético/metabolismo
4.
Epigenomics ; 14(17): 1039-1054, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36177720

RESUMO

Chronic kidney disease (CKD) is estimated to affect almost 10% of individuals worldwide and is one of the leading causes of morbidity and mortality. Renal fibrosis, a central pathway in CKD progression (irrespective of etiology), is associated with shortened or dysfunctional telomeres in animal studies. Telomeres are specialized nucleoprotein structures located at the chromosome end that maintain genomic integrity. The mechanisms of associations between telomere length and CKD have not yet been fully elucidated, however, CKD patients with shorter telomere length may have decreased renal function and a higher mortality rate. A plethora of ongoing research has focused on possible therapeutic applications of telomeres with the overall goal to preserve telomere length as a therapy to treat CKD.


Chronic kidney disease or CKD is one of the leading causes of illness and death worldwide. Scarring of the kidney tissue that occurs in CKD has been associated with shorter telomeres in studies using rats. Telomeres, said to act as the cellular 'shoelace caps', maintain the structure of chromosomes, allowing for genetic material inside cells to divide correctly. The length of telomeres (TL) is influenced by diverse factors such as genetics and lifestyle. The underlying processes for the associations between TL and CKD are still not understood, however, patients with CKD and shorter TL have reduced kidney function and an increased death rate. Therefore, research is focused on possible ways to preserve TL and treat CKD.


Assuntos
Insuficiência Renal Crônica , Telômero , Animais , Fibrose , Estudos Longitudinais , Nucleoproteínas/genética , Insuficiência Renal Crônica/genética , Insuficiência Renal Crônica/terapia , Telômero/genética
5.
Dev Psychol ; 58(7): 1298-1317, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35511516

RESUMO

The sustaining environments hypothesis theorizes that the lasting effects of PreK programs are contingent on the quality of the subsequent learning environment in early elementary school. The current study tests this theory by leveraging data from students (N = 462) who did and did not enroll in the Boston Public Schools (BPS) prekindergarten (PreK) program as well as features of their kindergarten instruction measured at the child- and classroom-levels using surveys and observations. Taken together, findings revealed limited evidence for the sustaining environments hypothesis. The bulk of the results were null, indicating that in general, associations between enrollment in BPS PreK and language, literacy, and math skills through the spring of kindergarten did not vary by kindergarten instructional experiences. When examining distinct types of instructional experiences, there were some inklings that child-level observational measures of kindergarten learning experiences-particularly those capturing constrained versus unconstrained instruction-were more predictive of PreK persistence than observed global classroom quality measures or survey-based measures of advanced instruction. However, these associations were not always specific to outcomes matching the content delivered during this instruction (math vs. literacy), consistent with the possibility of either cross-domain effects or that instructional variables are proxies for more general instructional practices. Findings for future research and theory are discussed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Assuntos
Instituições Acadêmicas , Estudantes , Escolaridade , Humanos , Aprendizagem , Alfabetização
6.
Sex Dev ; 15(5-6): 432-440, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34794153

RESUMO

The mammalian Y chromosome has evolved in many species into a specialized chromosome that contributes to sex development among other male phenotypes. This function is well studied in terms of protein-coding genes. Less is known about the noncoding genome on the Y chromosome and its contribution to both sex development and other traits. Once considered junk genetic material, noncoding RNAs are now known to contribute to the regulation of gene expression and to play an important role in refining cellular functions. The prime examples are noncoding genes on the X chromosome, which mitigate the differential dosage of genes on sex chromosomes. Here, we discuss the evolution of noncoding RNAs on the Y chromosome and the emerging evidence of how micro, long, and circular noncoding RNAs transcribed from the Y chromosome contribute to sex differentiation. We briefly touch on emerging evidence that these noncoding RNAs also contribute to some other important clinical phenotypes in humans.


Assuntos
Mecanismo Genético de Compensação de Dose , Cromossomo X , Animais , Masculino , Fenótipo , Cromossomos Sexuais/genética , Cromossomo Y
7.
Sci Total Environ ; 793: 148630, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34328994

RESUMO

For the first time, background threshold values have been developed for a large suite of sediment quality parameters from 969 lakes spanning the conterminous United States (U.S.). These values provide a statistical basis for estimating current ambient background, which refers to chemical and physical (e.g., grain size) concentrations derived from natural and/or widespread diffuse anthropogenic sources (e.g., nonpoint sources like atmospheric deposition and land runoff). Surficial sediment quality data, collected based on the randomized, probability-based sampling design of the 2017 National Lakes Assessment (NLA) study, were utilized for this effort. These data included 16 metal(loid)s, 25 polycyclic aromatic hydrocarbons (PAHs), 53 polychlorinated biphenyl (PCB) congeners, 27 legacy organochlorine pesticides and metabolites, total organic carbon (TOC), and grain size parameters. The data were analyzed based on different geographic areas, including: 10 U.S. Environmental Protection Agency (EPA) Regions, two major ecoregions bisecting the State of Minnesota (i.e., Temperate Plains and Upper Midwest), and for Minnesota. Hypothesis testing of 47 sediment quality parameters was performed on three geographic areas bisecting Minnesota, and there were many statistically significant (p < 0.05) differences between geographic pairs that included Minnesota. Background threshold values were calculated for parameters with >20% detects using 95% one-sided upper tolerance limit (UTL) with 95% coverage (UTL95-95) values. The UTL95-95 represents the value below which 95% of the population values are expected to fall with 95% confidence. These values were compared to matching sediment quality guidelines for the protection of benthic organisms, both with and without potential outliers removed. Applications and limitations of the UTL95-95 values are discussed. Jurisdictions within the continental U.S. could use these same publicly available sediment quality data to calculate UTL95-95 values for specific geographic areas, and other countries could design similar probabilistic field studies to determine current ambient background of sediment quality parameters in lake sediments.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Monitoramento Ambiental , Sedimentos Geológicos , Lagos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Estados Unidos , Poluentes Químicos da Água/análise
8.
Eur Heart J ; 41(48): 4580-4588, 2020 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-33206176

RESUMO

AIMS: Angiotensin-converting enzyme 2 (ACE2) is the cellular entry point for severe acute respiratory syndrome coronavirus (SARS-CoV-2)-the cause of coronavirus disease 2019 (COVID-19). However, the effect of renin-angiotensin system (RAS)-inhibition on ACE2 expression in human tissues of key relevance to blood pressure regulation and COVID-19 infection has not previously been reported. METHODS AND RESULTS: We examined how hypertension, its major metabolic co-phenotypes, and antihypertensive medications relate to ACE2 renal expression using information from up to 436 patients whose kidney transcriptomes were characterized by RNA-sequencing. We further validated some of the key observations in other human tissues and/or a controlled experimental model. Our data reveal increasing expression of ACE2 with age in both human lungs and the kidney. We show no association between renal expression of ACE2 and either hypertension or common types of RAS inhibiting drugs. We demonstrate that renal abundance of ACE2 is positively associated with a biochemical index of kidney function and show a strong enrichment for genes responsible for kidney health and disease in ACE2 co-expression analysis. CONCLUSION: Our results indicate that neither hypertension nor antihypertensive treatment is likely to alter the expression of the key entry receptor for SARS-CoV-2 in the human kidney. Our data further suggest that in the absence of SARS-CoV-2 infection, kidney ACE2 is most likely nephro-protective but the age-related increase in its expression within lungs and kidneys may be relevant to the risk of SARS-CoV-2 infection.


Assuntos
Enzima de Conversão de Angiotensina 2/genética , Enzima de Conversão de Angiotensina 2/metabolismo , Anti-Hipertensivos/farmacologia , Hipertensão , Túbulos Renais/metabolismo , Pulmão/metabolismo , Sistema Renina-Angiotensina/efeitos dos fármacos , Antagonistas Adrenérgicos beta/farmacologia , Adulto , Fatores Etários , Idoso , Antagonistas de Receptores de Angiotensina/farmacologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Animais , COVID-19/complicações , Diuréticos/farmacologia , Feminino , Perfilação da Expressão Gênica , Taxa de Filtração Glomerular , Humanos , Hipertensão/tratamento farmacológico , Hipertensão/genética , Túbulos Renais/fisiopatologia , Masculino , Pessoa de Meia-Idade , Ratos , Ratos Endogâmicos SHR , SARS-CoV-2 , Análise de Sequência de RNA , Fatores Sexuais , Transcriptoma/efeitos dos fármacos
9.
Int J Mol Sci ; 21(10)2020 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-32455975

RESUMO

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in adults in developed countries. CVD encompasses many diseased states, including hypertension, coronary artery disease and atherosclerosis. Studies in animal models and human studies have elucidated the contribution of many genetic factors, including non-coding RNAs. Non-coding RNAs are RNAs not translated into protein, involved in gene expression regulation post-transcriptionally and implicated in CVD. Of these, circular RNAs (circRNAs) and microRNAs are relevant. CircRNAs are created by the back-splicing of pre-messenger RNA and have been underexplored as contributors to CVD. These circRNAs may also act as biomarkers of human disease, as they can be extracted from whole blood, plasma, saliva and seminal fluid. CircRNAs have recently been implicated in various disease processes, including hypertension and other cardiovascular disease. This review article will explore the promising and emerging roles of circRNAs as potential biomarkers and therapeutic targets in CVD, in particular hypertension.


Assuntos
Doenças Cardiovasculares/genética , Hipertensão/genética , MicroRNAs/metabolismo , RNA Circular/metabolismo , RNA Longo não Codificante/metabolismo , Animais , Aterosclerose/genética , Aterosclerose/metabolismo , Biomarcadores/sangue , Biomarcadores/metabolismo , Cardiomiopatias/sangue , Cardiomiopatias/genética , Cardiomiopatias/metabolismo , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/metabolismo , MicroRNA Circulante/sangue , MicroRNA Circulante/genética , MicroRNA Circulante/metabolismo , Humanos , Hipertensão/sangue , Hipertensão/metabolismo , MicroRNAs/sangue , MicroRNAs/genética , Infarto do Miocárdio/sangue , Infarto do Miocárdio/genética , Infarto do Miocárdio/metabolismo , RNA Circular/sangue , RNA Circular/genética , RNA Longo não Codificante/sangue , RNA Longo não Codificante/genética
11.
Adv Child Dev Behav ; 53: 227-253, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28844245

RESUMO

A growing literature has demonstrated that early math skills are associated with later outcomes for children. This research has generated interest in improving children's early math competencies as a pathway to improved outcomes for children in elementary school. The Making Pre-K Count study was designed to test the effects of an early math intervention for preschoolers. Its design was unique in that, in addition to causally testing the effects of early math skills, it also allowed for the examination of a number of additional questions about scale-up, the influence of contextual factors and the counterfactual environment, the mechanism of long-term fade-out, and the role of measurement in early childhood intervention findings. This chapter outlines some of the design considerations and decisions put in place to create a rigorous test of the causal effects of early math skills that is also able to answer these questions in early childhood mathematics and intervention. The study serves as a potential model for how to advance science in the fields of preschool intervention and early mathematics.


Assuntos
Formação de Conceito , Intervenção Educacional Precoce/métodos , Comportamento Exploratório , Matemática/educação , Pré-Escolar , Currículo , Feminino , Humanos , Lactente , Masculino , Modelos Educacionais , Avaliação de Processos e Resultados em Cuidados de Saúde , Populações Vulneráveis
12.
Appl Environ Microbiol ; 82(13): 3857-3867, 2016 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-27107109

RESUMO

UNLABELLED: Through lethal infection, fungal parasites of phytoplankton ("chytrids") repackage organic material from the large, effectively inedible, colonial diatoms they infect into much smaller zoospores, which are easier for zooplankton to consume. However, their small size and lack of distinguishing morphological features render it difficult to distinguish zoospores from other small flagellates in mixed assemblages in the natural environment. In this study, we developed and tested a method to quantify chytrid zoospores in field studies using quantitative PCR (qPCR) targeting the internal transcribed spacer 2 (ITS2) region within the rRNA gene cluster. To achieve accurate quantification, the assay was designed to be highly specific for a parasite (Rhizophydium planktonicum) of the diatom Asterionella formosa; however, the approach is applicable to additional host-parasite systems. Parasitic zoospores were detected and quantified in the freshwater reaches of the lower Columbia River, as well as in the salt-influenced estuary and river plume. The coincidence between zoospore abundances and a prevalence of small zooplankton during blooms of large, colonial diatoms in the spring suggests that Columbia River zooplankton may be poised to benefit nutritionally from chytrid zoospores, thus providing a mechanism to retain organic carbon within the system and reduce losses to downstream export. We estimate that ∼15% of the carbon biomass tied up in blooms of the dominant diatom species is transformed into zoospores through the parasitic shunt during spring. IMPORTANCE: The small size of the parasitic fungi that infect phytoplankton makes it difficult to identify and quantify them in natural systems. We developed and tested a method to quantify these organisms (chytrid zoospores) using a molecular technique that targets the internal transcribed spacer region within the rRNA gene cluster. Using this method, we quantified the abundance of the motile stage of a specific parasite in the freshwater and saltwater-influenced regions of the Columbia River in the U.S. Pacific Northwest. Parasitic chytrid zoospores were found to be present throughout the year and at higher abundances during the spring, when phytoplankton blooms occur. The presence of these organisms indicates not only that they may be responsible for the death of host phytoplankton cells but that they may also provide a readily available food source to small consumers (zooplankton) in the food web of the Columbia River.


Assuntos
Quitridiomicetos/isolamento & purificação , Contagem de Colônia Microbiana , Micologia/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Rios/microbiologia , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Estados Unidos
13.
Appl Environ Microbiol ; 82(13): 3868-3874, 2016 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-27107112

RESUMO

UNLABELLED: Lethal parasitism of large phytoplankton by chytrids (microscopic zoosporic fungi) may play an important role in organic matter and nutrient cycling in aquatic environments by shunting carbon away from hosts and into much smaller zoospores, which are more readily consumed by zooplankton. This pathway provides a mechanism to more efficiently retain carbon within food webs and reduce export losses. However, challenges in accurate identification and quantification of chytrids have prevented a robust assessment of the relative importance of parasitism for carbon and energy flows within aquatic systems. The use of molecular techniques has greatly advanced our ability to detect small, nondescript microorganisms in aquatic environments in recent years, including chytrids. We used quantitative PCR (qPCR) to quantify the consumption of zoospores by Daphnia in laboratory experiments using a culture-based comparative threshold cycle (CT) method. We successfully quantified the reduction of zoospores in water samples during Daphnia grazing and confirmed the presence of chytrid DNA inside the daphnid gut. We demonstrate that comparative CT qPCR is a robust and effective method to quantify zoospores and evaluate zoospore grazing by zooplankton and will aid in better understanding how chytrids contribute to organic matter cycling and trophic energy transfer within food webs. IMPORTANCE: The study of aquatic fungi is often complicated by the fact that they possess complex life cycles that include a variety of morphological forms. Studies that rely on morphological characteristics to quantify the abundances of all stages of the fungal life cycle face the challenge of correctly identifying and enumerating the nondescript zoospores. These zoospores, however, provide an important trophic link between large colonial phytoplankton and zooplankton: that is, once the carbon is liberated from phytoplankton into the parasitic zoospores, the latter are consumed by zooplankton and carbon is retained in the aquatic food web rather than exported from the system. This study provides a tool to quantify zoospores and evaluate the consumption of zoospores by zooplankton in order to further our understanding of their role in food web dynamics.


Assuntos
Organismos Aquáticos/fisiologia , Daphnia/fisiologia , Comportamento Alimentar , Fungos/classificação , Fungos/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real/métodos , Animais , Fungos/genética , Trato Gastrointestinal/microbiologia
14.
Early Child Res Q ; 36: 49-63, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26807002

RESUMO

The increasing population of dual language learners (DLLs) entering preschool classrooms highlights a continued need for research on the development of dual language acquisition, and specifically vocabulary skills, in this age group. This study describes young DLL children's (N = 177) vocabulary development in both English and Spanish simultaneously, and how vocabulary skills in each language relate to one another, during a contextual shift that places greater emphasis on the acquisition of academic English language skills. Findings demonstrated that DLL preschoolers made gains in vocabulary in both languages with more change evidenced in receptive, in comparison to expressive, vocabulary as well as in English in comparison to Spanish. When examining whether children's vocabulary scores in one language at the beginning of preschool interact with their vocabulary scores in the other language to predict vocabulary growth, no significant associations were found for receptive vocabulary. In contrast, the interaction between initial English and Spanish expressive vocabulary scores was negatively related to growth in English expressive vocabulary. This cross-language association suggests that children who have low expressive vocabulary skills in both languages tend to grow faster in their English expressive vocabulary. The study extends previous work on dual language development by examining growth in expressive and receptive vocabulary in both English and Spanish. It also provides suggestions for future work to inform a more comprehensive understanding of DLL children's development in both languages.

15.
Child Dev ; 86(4): 1094-1111, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25906925

RESUMO

Significant differences in language and self-regulation skills exist among children when they enter formal schooling. Contributing to these language differences is a growing population of dual language learners (DLLs) in the United States. Given evidence linking self-regulatory processes and language development, this study explored bidirectional associations between English expressive vocabulary and self-regulation skills for monolingual English and DLL preschool children (N = 250) from mixed-income families in Los Angeles. Across three time points, findings provide initial support for bidirectionality between these developing skills for both monolinguals and DLLs. Results provide strong empirical support for vocabulary serving as a leading indicator of self-regulation skills in preschool. Findings also suggest that early self-regulation skills play a particularly important role for vocabulary development.

16.
J Appl Dev Psychol ; 34(6): 299-309, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-26722137

RESUMO

This study examined the quality of preschool classroom experiences through the combination of teachers' interactions at the classroom level and children's individual patterns of engagement in predicting children's gains in school readiness. A sample of 605 children and 309 teachers participated. The quality of children's engagement and teacher interactions was directly observed in the classroom setting, and direct assessments of children's school readiness skills were obtained in the fall and again in the spring. The quality of teacher interactions was associated with gains across all school readiness skills. The effect of children's individual classroom engagement on their gains in school readiness skills (specifically phonological awareness and expressive vocabulary) was moderated by classroom level teacher interactions. The results suggest that if teachers provide highly responsive interactions at the classroom level, children may develop more equitable school readiness skills regardless of their individual engagement patterns.

17.
Cancer Res ; 68(12): 4693-700, 2008 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-18559515

RESUMO

The binding of exogenous nicotine to nicotinic acetylcholine (ACh) receptors (nAChR) and the binding of endogenous ACh to both nAChR and muscarinic ACh receptors (mAChR) stimulate growth of both small cell and non-small cell lung carcinomas. Understanding how cholinergic signaling is up-regulated in lung cancer may suggest new therapeutic approaches. Analysis of 28 squamous cell lung carcinomas (SCC) showed increased levels of alpha5 and beta3 nAChR mRNA and increased levels of ACh associated with increased levels of choline acetyltransferase mRNA and decreased cholinesterase mRNAs. Lynx1, an allosteric inhibitor of nAChR activity, was also decreased in SCC. Thus, cholinergic signaling is broadly increased in SCC caused by increased levels of receptors, increased levels of ligands, and decreased levels of receptor inhibitors. Partially explaining the cholinergic up-regulation seen in SCC, incubation of the H520 SCC cell line with nicotine increased levels of ACh secretion, increased expression of nAChR, and, as measured by electrophysiologic recording, increased activity of the expressed nAChR. Consistent with these effects, nicotine stimulated proliferation of H520 cells. One approach to blocking proliferative effects of nicotine and ACh on growth of lung cancers may be through M3 mAChR antagonists, which can limit the activation of mitogen-activated protein kinase that is caused by both nicotinic and muscarinic signaling. This was tested with the M3-selective muscarinic antagonist darifenacin. Darifenacin blocked nicotine-stimulated H520 growth in vitro and also blocked H520 growth in nude mice in vivo. Thus, cholinergic signaling is broadly up-regulated in SCC and blocking cholinergic signaling can limit basal and nicotine-stimulated growth of SCC.


Assuntos
Acetilcolina/metabolismo , Carcinoma de Células Escamosas/genética , Colina O-Acetiltransferase/genética , Neoplasias Pulmonares/genética , Glicoproteínas de Membrana/genética , Receptor Muscarínico M3/genética , Receptores Nicotínicos/genética , Proteínas Vesiculares de Transporte de Acetilcolina/genética , Proteínas Adaptadoras de Transdução de Sinal , Animais , Benzofuranos/farmacologia , Western Blotting , Cálcio/metabolismo , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/prevenção & controle , Proliferação de Células , Células Cultivadas , Colina O-Acetiltransferase/metabolismo , Eletrofisiologia , Proteínas Ligadas por GPI , Humanos , Pulmão/metabolismo , Pulmão/patologia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/prevenção & controle , Masculino , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Nus , Antagonistas Muscarínicos/farmacologia , Nicotina/farmacologia , Fosforilação/efeitos dos fármacos , Pirrolidinas/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptor Muscarínico M3/metabolismo , Receptores Nicotínicos/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Proteínas Vesiculares de Transporte de Acetilcolina/metabolismo
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