RESUMO
OBJECTIVES: Numerous risk factors for sleep disruption in critically ill adults have been described. We performed a systematic review of all risk factors associated with sleep disruption in the ICU setting. DATA SOURCES: PubMed, EMBASE, CINAHL, Web of Science, Cochrane Central Register for Controlled Trials, and Cochrane Database of Systematic Reviews. STUDY SELECTION: English-language studies of any design published between 1990 and April 2018 that evaluated sleep in greater than or equal to 10 critically ill adults (> 18 yr old) and investigated greater than or equal to 1 potential risk factor for sleep disruption during ICU stay. We assessed study quality using Newcastle-Ottawa Scale or Cochrane Risk of Bias tool. DATA EXTRACTION: We abstracted all data independently and in duplicate. Potential ICU sleep disruption risk factors were categorized into three categories based on how data were reported: 1) patient-reported reasons for sleep disruption, 2) patient-reported ratings of potential factors affecting sleep quality, and 3) studies reporting a statistical or temporal association between potential risk factors and disrupted sleep. DATA SYNTHESIS: Of 5,148 citations, we included 62 studies. Pain, discomfort, anxiety/fear, noise, light, and ICU care-related activities are the most common and widely studied patient-reported factors causing sleep disruption. Patients rated noise and light as the most sleep-disruptive factors. Higher number of comorbidities, poor home sleep quality, home sleep aid use, and delirium were factors associated with sleep disruption identified in available studies. CONCLUSIONS: This systematic review summarizes all premorbid, illness-related, and ICU-related factors associated with sleep disruption in the ICU. These findings will inform sleep promotion efforts in the ICU and guide further research in this field.
Assuntos
Estado Terminal , Privação do Sono/etiologia , Humanos , Unidades de Terapia Intensiva , Fatores de RiscoRESUMO
ABSTARCT: New anti-fibrotic agents for idiopathic pulmonary fibrosis (IPF) were approved based on the results of forced vital capacity (FVC) trends, although concerns were raised about the reliability of FVC as the only endpoint parameter. We hypothesized that IPF-specific multi-dimensional scores (Composite Physiologic Index-CPI; gender-age-physiology-GAP; risk stratification score-RISE) would better capture response to therapy. In this pilot study, treated and untreated cohorts of IPF patients, matched for demographic and functional characteristics were prospectively followed for 1 year, at 4-month intervals. Progression-free survival was significantly improved in treated patients (p = 0.0093). While no difference in FVC longitudinal trends was observed, MRC dyspnea score (p = 0.0347), diffusing lung capacity (p = 0.0015), 6-min walk distance (p = 0.0007), CPI (p = 0.0457) and RISE (p = 0.0005) were significantly stabilized in treated patients, compared to steady worsening in untreated subjects. Multi-dimensional scores provide broader spectrum of prognostic information and may facilitate the assessment of efficacy of new drugs for IPF.
Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Fibrose Pulmonar Idiopática/tratamento farmacológico , Fibrose Pulmonar Idiopática/fisiopatologia , Piridonas/uso terapêutico , Idoso , Intervalo Livre de Doença , Dispneia/etiologia , Feminino , Volume Expiratório Forçado , Humanos , Fibrose Pulmonar Idiopática/complicações , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Capacidade de Difusão Pulmonar , Resultado do Tratamento , Capacidade Vital , Teste de CaminhadaRESUMO
ERα is expressed in macrophages and other immune cells known to exert dramatic effects on glucose homeostasis. We investigated the impact of ERα expression on macrophage function to determine whether hematopoietic or myeloid-specific ERα deletion manifests obesity-induced insulin resistance in mice. Indeed, altered plasma adipokine and cytokine levels, glucose intolerance, insulin resistance, and increased adipose tissue mass were observed in animals harboring a hematopoietic or myeloid-specific deletion of ERα. A similar obese phenotype and increased atherosclerotic lesion area was displayed in LDL receptor-KO mice transplanted with ERα(-/-) bone marrow. In isolated macrophages, ERα was necessary for repression of inflammation, maintenance of oxidative metabolism, IL-4-mediated induction of alternative activation, full phagocytic capacity in response to LPS, and oxidized LDL-induced expression of ApoE and Abca1. Furthermore, we identified ERα as a direct regulator of macrophage transglutaminase 2 expression, a multifunctional atheroprotective enzyme. Our findings suggest that diminished ERα expression in hematopoietic/myeloid cells promotes aspects of the metabolic syndrome and accelerates atherosclerosis in female mice.
Assuntos
Aterosclerose/patologia , Medula Óssea/metabolismo , Receptor alfa de Estrogênio/fisiologia , Homeostase , Adiposidade , Animais , Receptor alfa de Estrogênio/genética , Receptor alfa de Estrogênio/metabolismo , Feminino , Glucose/metabolismo , Resistência à Insulina , Interleucina-4/fisiologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
Prolactin (PRL) is essential for normal reproduction and signals through two types of receptors, the short (PRL-RS) and long (PRL-RL) form. We have previously shown that transgenic mice expressing only PRL-RS (PRLR(-/-)RS) display abnormal follicular development and premature ovarian failure. Here, we report that MAPK, essential for normal follicular development, is critically inhibited by PRL in reproductive tissues of PRLR(-/-)RS mice. Consequently, the phosphorylation of MAPK downstream targets are also markedly inhibited by PRL without affecting immediate upstream kinases, suggesting involvement of MAPK specific phosphatase(s) in this inhibition. Similar results are obtained in a PRL-responsive ovary-derived cell line (GG-CL) that expresses only PRL-RS. However, we found the expression/activation of several known MAPK phosphatases not to be affected by PRL, suggesting a role of unidentified phosphatase(s). We detected a 27-kDa protein that binds to the intracellular domain of PRL-RS and identified it as dual specific phosphatase DUPD1. PRL does not induce expression of DUDP1 but represses its phosphorylation on Thr-155. We also show a physical association of this phosphatase with ERK1/2 and p38 MAPK. Using an in vitro phosphatase assay and overexpression studies, we established that DUPD1 is a MAPK phosphatase. Dual specific phosphatase inhibitors as well as siRNA to DUPD1, completely prevent PRL-mediated MAPK inhibition in ovarian cells. Our results strongly suggest that deactivation of MAPK by PRL/PRL-RS contributes to the severe ovarian defect in PRLR(-/-)RS mice and demonstrate the novel association of PRL-RS with DUPD1 and a role for this phosphatase in MAPK deactivation.
Assuntos
Decídua/metabolismo , Fosfatase 1 de Especificidade Dupla/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Ovário/metabolismo , Prolactina/metabolismo , Receptores da Prolactina/metabolismo , Animais , Linhagem Celular , Decídua/citologia , Fosfatase 1 de Especificidade Dupla/genética , Feminino , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Camundongos Transgênicos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Ovário/citologia , Ovário/crescimento & desenvolvimento , Monoéster Fosfórico Hidrolases/antagonistas & inibidores , Monoéster Fosfórico Hidrolases/metabolismo , Gravidez , Insuficiência Ovariana Primária/metabolismo , Insuficiência Ovariana Primária/fisiopatologia , Ratos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Prolactin (PRL), a pleiotropic hormone essential for maintenance of corpus luteum (CL) function and pregnancy, transduces its signal through two types of receptors, a short form (PRLR-S) and a long form (PRLR-L). Both types of receptors are expressed in the CL, yet their individual roles are not well defined. We have shown previously that female transgenic mice expressing only PRLR-S display total infertility characterized by defective follicular development and early degeneration of CL, suggesting that expression of PRLR-L is a prerequisite for normal follicular development and maintenance of CL. To determine whether PRLR-L alone is the sole receptor required to maintain normal CL formation, differentiation, and progesterone secretion, we generated two transgenic mice which express only PRLR-L, either ubiquitously (Tg-RL) or in a CL-specific manner (CL-RL). To generate CL-specific expression, we used the HSD17B7 promoter. We found both transgenic mice models cycled normally, displayed no apparent defect in follicular development, and had normal ovulation rates. The STAT5 signaling pathway, considered essential for luteinization and progesterone production, was activated by PRL in both transgenic mice models. However, soon after mating, Tg-RL and CL-RL mice showed early regression of CL, lack of progesterone production, and implantation failure that rendered them totally infertile. Embryo transfer studies demonstrated no embryo abnormalities, and supplementation with progesterone rescued implantation failure in these mice. Close observation revealed lack of luteinization and reduced expression of proteins involved in progesterone biosynthesis despite normal levels of LHCGR (LH-R), ESR1 (ER-alpha), CEBPB (C/EBP-beta) and CDKN1B (p27), proteins essential for luteinization. However, we found VEGFA, a key regulator of angiogenesis and vascularization, to be dramatically reduced in both Tg-RL and CL-RL mice. We also found collagen IV, a marker for the basal lamina of endothelial cells, aberrantly expressed and a discordant organization of endothelial cells in CL. Although luteinization did not occur in vivo, granulosa cells isolated from these mice luteinized in culture. Taken together, these results suggest that a vascularization defect in the CL may be responsible for lack of luteinization, progesterone production, and infertility in mice expressing only PRLR-L. This investigation therefore demonstrates that in contrast to earlier presumptions that PRLR-L alone is able to support normal CL formation and function, both isoforms of the PRL receptor are required in the CL for normal female fertility.
Assuntos
Ovário/fisiologia , Receptores da Prolactina/química , Receptores da Prolactina/fisiologia , Transdução de Sinais/fisiologia , Animais , Corpo Lúteo/fisiologia , Feminino , Infertilidade Feminina/metabolismo , Infertilidade Feminina/fisiopatologia , Camundongos , Camundongos Transgênicos , Modelos Animais , Progesterona/metabolismo , Isoformas de Proteínas , Receptores da Prolactina/genética , Fatores de Transcrição STAT/fisiologiaRESUMO
Thiazolidinediones (TZDs) are insulin-sensitizing drugs and are potent agonists of the nuclear peroxisome proliferator-activated receptor-gamma (PPAR-gamma). Although muscle is the major organ responsible for insulin-stimulated glucose disposal, PPAR-gamma is more highly expressed in adipose tissue than in muscle. To address this issue, we used the Cre-loxP system to knock out Pparg, the gene encoding PPAR-gamma, in mouse skeletal muscle. As early as 4 months of age, mice with targeted disruption of PPAR-gamma in muscle showed glucose intolerance and progressive insulin resistance. Using the hyperinsulinemic-euglycemic clamp technique, the in vivo insulin-stimulated glucose disposal rate (IS-GDR) was reduced by approximately 80% and was unchanged by 3 weeks of TZD treatment. These effects reveal a crucial role for muscle PPAR-gamma in the maintenance of skeletal muscle insulin action, the etiology of insulin resistance and the action of TZDs.
Assuntos
Resistência à Insulina/fisiologia , Proteínas Musculares , Músculo Esquelético/metabolismo , Receptores Citoplasmáticos e Nucleares/deficiência , Receptores Citoplasmáticos e Nucleares/genética , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/metabolismo , Animais , Expressão Gênica/efeitos dos fármacos , Técnica Clamp de Glucose , Transportador de Glucose Tipo 4 , Insulina/metabolismo , Resistência à Insulina/genética , Fígado/efeitos dos fármacos , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Proteínas de Transporte de Monossacarídeos/metabolismo , Músculo Esquelético/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Citoplasmáticos e Nucleares/agonistas , Transdução de Sinais , Tiazolidinedionas/farmacologia , Fatores de Transcrição/agonistasRESUMO
BACKGROUND: It has been well established that prolactin (PRL) signals through the long form of its receptor (PRL-RL) and activates the Jak/Stat pathway for transcription of PRL target genes. However, signaling pathways mediated through the short PRL-R isoform (PRL-RS) remains controversial. Our recent finding that PRL signaling through PRL-RS represses two transcription factors critical for follicular development lead us to examine other putative PRL/PRL-RS target transcription factors in the decidua and ovary, two well-known target tissues of PRL action in reproduction. METHODS: In this investigation we used mice expressing PRL-RS on a PRL-R knockout background and a combo protein/DNA array to study the transcription factors regulated by PRL through PRL-RS only. RESULTS: We show that PRL activation of the PRL-RS receptor either stimulates or inhibits the DNA binding activity of a substantial number of transcription factors in the decidua as well as ovary. We found few transcription factors to be similarly regulated in both tissues, while most transcription factors are oppositely regulated by PRL in the decidua and ovary. In addition, some transcription factors are regulated by PRL only in the ovary or only in the decidua. Several of these transcription factors are involved in physiological pathways known to be regulated by PRL while others are novel. CONCLUSION: Our results clearly indicate that PRL does signal through PRL-RS in the decidua as well as the ovary, independently of PRL-RL, and activates/represses transcription factors in a tissue specific manner. This is the first report showing PRL/PRL-RS regulation of specific transcription factors. Many of these transcription factors were not previously known to be PRL targets, suggesting novel physiological roles for this hormone.
Assuntos
DNA/metabolismo , Decídua/efeitos dos fármacos , Ovário/efeitos dos fármacos , Prolactina/farmacologia , Receptores da Prolactina/metabolismo , Fatores de Transcrição/metabolismo , Animais , Fator de Transcrição CDX2 , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , DNA/genética , Decídua/metabolismo , Ensaio de Desvio de Mobilidade Eletroforética , Proteínas do Olho/genética , Proteínas do Olho/metabolismo , Feminino , Expressão Gênica/efeitos dos fármacos , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos , Camundongos Knockout , Camundongos Transgênicos , Ovário/metabolismo , Fator de Transcrição PAX5/genética , Fator de Transcrição PAX5/metabolismo , Fator de Transcrição PAX6 , Fatores de Transcrição Box Pareados/genética , Fatores de Transcrição Box Pareados/metabolismo , Gravidez , Prolactina/administração & dosagem , Ligação Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Receptores da Prolactina/genética , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Fatores de Tempo , Fatores de Transcrição/genéticaRESUMO
Our laboratory has previously cloned and purified a protein named PRAP (prolactin receptor-associated protein) that was shown to be a novel 17beta-hydroxysteroid dehydrogenase (HSD) enzyme with dual activity. This enzyme, renamed HSD17B7 or PRAP/17beta-HSD7, converts estrone to estradiol and is also involved in cholesterol biosynthesis. The major site of its expression is the corpus luteum of a great number of species including rodents and humans. To examine the functional significance of HSD17B7 in pregnancy, we generated a knockout mouse model with targeted deletions of exons 1-4 of this gene. We anticipated a mouse with a severe fertility defect due to its inability to regulate estrogen levels during pregnancy. The heterozygous mutant mice are normal in their development and gross anatomy. The females cycle normally, and both male and female are fertile with normal litter size. To our surprise, the breeding of heterozygous mice yielded no viable HSD17B7 null mice. However, we found HSD17B7 null embryo alive in utero on d 8.5 and d 9.5. By d 10.5, the fetuses grow and suffer from severe brain malformation and heart defect. Because the brain depends on in situ cholesterol biosynthesis for its development beginning at d 10, the major cause of fetal death appears to be due to the cholesterol synthetic activity of this enzyme. By ablating HSD17B7 function, we have uncovered, in vivo, an important requirement for this enzyme during fetal development.
Assuntos
17-Hidroxiesteroide Desidrogenases/metabolismo , Embrião de Mamíferos/fisiologia , Fosfoproteínas/metabolismo , 17-Hidroxiesteroide Desidrogenases/genética , Animais , Embrião de Mamíferos/anatomia & histologia , Feminino , Marcação de Genes , Hibridização In Situ , Masculino , Camundongos , Camundongos Knockout , Fosfoproteínas/genética , Gravidez , Distribuição TecidualRESUMO
Prolactin (PRL) is a hormone with over 300 biological activities. Although the signaling pathway downstream of the long form of its receptor (RL) has been well characterized, little is known about PRL actions upon activation of the short form (RS). Here, we show that mice expressing only RS exhibit an ovarian phenotype of accelerated follicular recruitment followed by massive follicular death leading to premature ovarian failure. Consequently, RS-expressing ovaries of young adults are depleted of functional follicles and formed mostly by interstitium. We also show that activation of RS represses the expression of the transcription factor Forkhead box O3 (FOXO3) and that of the enzyme galactose-1-phosphate uridyltransferase (Galt), two proteins known to be essential for normal follicular development. Our finding that FOXO3 regulates the expression of Galt and enhances its transcriptional activity indicates that it is the repression of FOXO3 by PRL acting through RS that prevents Galt expression in the ovary and causes follicular death. Coexpression of RL with RS prevents PRL inhibition of Galt, and the ovarian defect is no longer seen in RS transgenic mice that coexpress RL, suggesting that RL prevents RS-induced ovarian impairment. In summary, we show that PRL signals through RS and causes, in the absence of RL, a severe ovarian pathology by repressing the expression of FOXO3 and that of its target gene Galt. We also provide evidence of a link between the premature ovarian failure seen in mice expressing RS and in mice with FOXO3 gene deletion as well as in human with Galt mutation.
Assuntos
Fatores de Transcrição Forkhead/metabolismo , Ovário/metabolismo , Prolactina/fisiologia , Receptores da Prolactina/fisiologia , Transdução de Sinais , Animais , Western Blotting , Linhagem Celular Tumoral , Ensaio de Desvio de Mobilidade Eletroforética , Feminino , Proteína Forkhead Box O3 , Fatores de Transcrição Forkhead/genética , Regulação da Expressão Gênica , Genótipo , Humanos , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Folículo Ovariano/crescimento & desenvolvimento , Folículo Ovariano/metabolismo , Ovário/patologia , Prolactina/sangue , Receptores da Prolactina/genética , Receptores da Prolactina/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transcrição Gênica , UTP-Hexose-1-Fosfato Uridililtransferase/genética , UTP-Hexose-1-Fosfato Uridililtransferase/metabolismoRESUMO
Wrinkled gold thin films on elastomeric substrates are used as robust parallel plate electrodes for soft capacitive pressure sensors. The wrinkled structures create a robust integration with the polymer, allowing repeated normal force to deform the thin film without failure. By incorporating microridged structures that support the counter electrodes to create air cavities within the elastomeric dielectric layer, pressure sensitivity is further increased to 0.148 kPa-1 over a wide dynamic range of up to 10 kPa. The wide dynamic range and pressure sensitivity of the pressure sensor allow for consistent measurements of the pressure exerted by the radial artery located on the wrist. The soft capacitive pressure sensor displays comparable results when tested against an FDA approved device (Clearsight, Edwards Lifesciences, Irvine, CA) measuring beat-to-beat blood pressure. These soft pressure sensors using wrinkled thin films, therefore, illustrate considerable potential to continuously monitor beat-to-beat blood pressure.
Assuntos
Pressão Sanguínea/fisiologia , Monitorização Fisiológica/métodos , Dispositivos Eletrônicos Vestíveis , Eletrodos , Ouro/química , Humanos , Monitorização Fisiológica/instrumentaçãoRESUMO
Increased heat shock protein (HSP) 72 expression in skeletal muscle prevents obesity and glucose intolerance in mice, although the underlying mechanisms of this observation are largely unresolved. Herein we show that HSP72 is a critical regulator of stress-induced mitochondrial triage signaling since Parkin, an E3 ubiquitin ligase known to regulate mitophagy, was unable to ubiquitinate and control its own protein expression or that of its central target mitofusin (Mfn) in the absence of HSP72. In wild-type cells, we show that HSP72 rapidly translocates to depolarized mitochondria prior to Parkin recruitment and immunoprecipitates with both Parkin and Mfn2 only after specific mitochondrial insult. In HSP72 knockout mice, impaired Parkin action was associated with retention of enlarged, dysmorphic mitochondria and paralleled by reduced muscle respiratory capacity, lipid accumulation, and muscle insulin resistance. Reduced oxygen consumption and impaired insulin action were recapitulated in Parkin-null myotubes, confirming a role for the HSP72-Parkin axis in the regulation of muscle insulin sensitivity. These data suggest that strategies to maintain HSP72 may provide therapeutic benefit to enhance mitochondrial quality and insulin action to ameliorate complications associated with metabolic diseases, including type 2 diabetes.
Assuntos
Proteínas de Choque Térmico HSP72/metabolismo , Insulina/metabolismo , Mitocôndrias/metabolismo , Músculo Esquelético/metabolismo , Estresse Oxidativo/fisiologia , Ubiquitina-Proteína Ligases/metabolismo , Animais , Respiração Celular/efeitos dos fármacos , Respiração Celular/fisiologia , Células HEK293 , Proteínas de Choque Térmico HSP72/genética , Humanos , Insulina/farmacologia , Resistência à Insulina/fisiologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/fisiologia , Camundongos , Camundongos Knockout , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Músculo Esquelético/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , Consumo de Oxigênio/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Ubiquitina-Proteína Ligases/genéticaRESUMO
Our laboratory has previously cloned and purified an ovarian protein found to be a novel 17ß-hydroxysteroid dehydrogenase type 7 enzyme (HSD17B7) (formerly prolactin receptor-associated protein) that converts the weak estrogen, estrone, to the highly potent estradiol. The regulation of this enzyme has not yet been explored. In this report, we show high expression of HSD17B7 in human ductal carcinoma and breast cancer cell lines and present evidence for a strong up-regulation of this enzyme by estradiol at the level of mRNA, protein expression, and promoter activity in MCF-7 cells. The effect of estradiol is mediated by estrogen receptor (ER)α, whereas ERß prevents this stimulation. ER antagonists, ICI 182,780 and 4-hydroxytamoxifen, prevent estradiol-induced stimulation of the endogenously expressed HSD17B7, suggesting that these inhibitors not only block estradiol action but also its production. We have identified a -185-bp region of the hsd17b7 promoter that is highly conserved among rat, mouse, and human and confers regulation by estradiol in MCF-7 cells. This region is devoid of a classical estradiol-response element but contains a nuclear factor 1 (NF1) site that is essential for estradiol action. We found that estradiol stimulates the recruitment and DNA binding of NF1 to this region of the hsd17b7 promoter. Furthermore, knockdown of NF1 family members, NF1B, NF1A, and NF1X, completely prevents induction of this gene by estradiol. In summary, our findings demonstrate that estradiol stimulates HSD17B7 transcriptional activity in breast cancer cells through a novel mechanism requiring NF1 and strongly suggest a positive feedback mechanism to increase local estradiol synthesis causing growth of estrogen-dependent breast cancers.
Assuntos
Neoplasias da Mama/metabolismo , Carcinoma Ductal de Mama/metabolismo , Proteínas de Ciclo Celular/genética , Estradiol/biossíntese , Proteínas S100/genética , Animais , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/metabolismo , Retroalimentação Fisiológica , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Soros Imunes , Glândulas Mamárias Animais/metabolismo , Glândulas Mamárias Animais/patologia , Camundongos , Fatores de Transcrição NFI/genética , Fatores de Transcrição NFI/metabolismo , Neoplasias Hormônio-Dependentes/metabolismo , Neoplasias Hormônio-Dependentes/patologia , Coelhos , Elementos de Resposta , Proteína A6 Ligante de Cálcio S100 , Proteínas S100/metabolismo , Transcrição GênicaRESUMO
Prolactin (PRL) affects the development and function of the reproductive system by binding to two types of receptors, which differ by the size of their intracellular domain in rodents. Whereas the signaling pathway through the long form of the receptor (PRL-RL) is well characterized, signaling through the short form (PRL-RS) remains obscure. In this investigation, we examined transcription factors regulated by PRL in the ovary and decidua of mice expressing only PRL-RS in a PRL receptor null background. These mice provide a powerful in vivo model to study the selective signaling mechanism of PRL through PRL-RS independent of PRL-RL. We also examined the regulation of transcription factors in ovarian and uterine cell lines stably transfected with PRL-RS or PRL-RL. We focused our investigation on transcription factors similarly regulated in both these tissues and clearly established that signaling through PRL-RS does not activate the JaK/Stat in vivo but leads to severe down-regulation of Sp1 expression, DNA binding activity, and nuclear localization, events that appear to involve the calmodulin-dependent protein kinase pathway. Our in vivo and in culture data demonstrate that the PRL-RS activates a signaling pathway distinct from that of the PRL-RL.
Assuntos
Prolactina/fisiologia , Receptores da Prolactina/fisiologia , Fatores de Transcrição STAT/fisiologia , Transdução de Sinais/fisiologia , Fator de Transcrição Sp1/fisiologia , Fatores de Transcrição/metabolismo , Animais , Linhagem Celular , Decídua/efeitos dos fármacos , Decídua/fisiologia , Feminino , Janus Quinase 2/metabolismo , Camundongos , Camundongos Transgênicos , Ovário/efeitos dos fármacos , Ovário/fisiologia , Ratos , Receptores da Prolactina/genética , Fator de Transcrição Sp1/antagonistas & inibidoresRESUMO
In the present investigation, we studied the effects of thiazolidinedione (TZD) treatment on insulin-stimulated fatty acid (FA) and glucose kinetics in perfused muscle from high-fat (HF)-fed rats. We tested the hypothesis that TZDs prevent FA-induced insulin resistance by attenuating proinflammatory signaling independently of myocellular lipid levels. Male Wistar rats were assigned to one of three 3-wk dietary groups: control chow fed (CON), 65% HF diet (HFD), or TZD- (troglitazone or rosiglitazone) enriched HF diet (TZD + HFD). TZD treatment led to a significant increase in plasma membrane content of CD36 protein in muscle (red: P = 0.01, and white: P = 0.001) that correlated with increased FA uptake (45%, P = 0.002) and triacylglycerol (TG) synthesis (46%, P = 0.03) during the perfusion. Importantly, whereas HF feeding caused increased basal TG (P = 0.047), diacylglycerol (P = 0.002), and ceramide (P = 0.01) levels, TZD treatment only prevented the increase in muscle ceramide. In contrast, all of the muscle inflammatory markers altered by HF feeding ( upward arrowNIK protein content, P = 0.009; upward arrowIKKbeta activity, P = 0.006; downward arrowIkappaB-alpha protein, P = 0.03; and upward arrowJNK phosphorylation, P = 0.003) were completely normalized by TZD treatment. Consistent with this, HFD-induced decrements in insulin action were also prevented by TZD treatment. Thus our findings support the notion that TZD treatment causes increased FA uptake and TG accumulation in skeletal muscle under insulin-stimulated conditions. Despite this, TZDs suppress the inflammatory response to dietary lipid overload, and it is this mechanism that correlates strongly with insulin sensitivity.
Assuntos
Gorduras na Dieta/efeitos adversos , Inflamação/prevenção & controle , Resistência à Insulina , Músculo Esquelético/efeitos dos fármacos , Tiazolidinedionas/farmacologia , Triglicerídeos/biossíntese , Animais , Ácidos Graxos/efeitos adversos , Glucose/metabolismo , Membro Posterior/química , Inflamação/etiologia , Insulina/metabolismo , Lipídeos/sangue , Masculino , Músculo Esquelético/metabolismo , Ácido Palmítico/metabolismo , Ratos , Ratos WistarRESUMO
FoxO transcription factors are important targets of insulin action. To better understand the role of FoxO proteins in the liver, we created transgenic mice expressing constitutively active FoxO1 in the liver using the alpha1-antitrypsin promoter. Fasting glucose levels are increased, and glucose tolerance is impaired in transgenic (TGN) versus wild type (WT) mice. Interestingly, fasting triglyceride and cholesterol levels are reduced despite hyperinsulinemia, and post-prandial changes in triglyceride levels are markedly suppressed in TGN versus WT mice. Activation of pro-lipogenic signaling pathways (atypical protein kinase C and protein kinase B) and the ability to suppress beta-hydroxybutyrate levels are not impaired in TGN. In contrast, de novo lipogenesis measured with (3)H(2)O is suppressed by approximately 70% in the liver of TGN versus WT mice after refeeding. Gene-array studies reveal that the expression of genes involved in gluconeogenesis, glycerol transport, and amino acid catabolism is increased, whereas genes involved in glucose utilization by glycolysis, the pentose phosphate shunt, lipogenesis, and sterol synthesis pathways are suppressed in TGN versus WT. Studies with adenoviral vectors in isolated hepatocytes confirm that FoxO1 stimulates expression of gluconeogenic genes and suppresses expression of genes involved in glycolysis, the shunt pathway, and lipogenesis, including glucokinase and SREBP-1c. Together, these results indicate that FoxO proteins promote hepatic glucose production through multiple mechanisms and contribute to the regulation of other metabolic pathways important in the adaptation to fasting and feeding in the liver, including glycolysis, the pentose phosphate shunt, and lipogenic and sterol synthetic pathways.
Assuntos
Fatores de Transcrição Forkhead/fisiologia , Regulação da Expressão Gênica , Fígado/enzimologia , Adenoviridae/genética , Animais , Bioquímica/métodos , Glicemia/metabolismo , Cromatografia Líquida de Alta Pressão , DNA Complementar/metabolismo , Proteína Forkhead Box O1 , Fatores de Transcrição Forkhead/metabolismo , Genoma , Gluconeogênese , Glucose/metabolismo , Glicerol/metabolismo , Glicólise , Hepatócitos/metabolismo , Humanos , Imuno-Histoquímica , Imunoprecipitação , Insulina/metabolismo , Lipídeos/química , Lipogênese , Lipase Lipoproteica/metabolismo , Fígado/metabolismo , Camundongos , Camundongos Transgênicos , Modelos Biológicos , Hibridização de Ácido Nucleico , Análise de Sequência com Séries de Oligonucleotídeos , Regiões Promotoras Genéticas , Proteína Quinase C/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo , Transcrição Gênica , Triglicerídeos/metabolismo , alfa 1-Antitripsina/genéticaRESUMO
Syndrome X, typified by obesity, insulin resistance (IR), dyslipidemia, and other metabolic abnormalities, is responsive to antidiabetic thiazolidinediones (TZDs). Peroxisome proliferator-activated receptor (PPAR) gamma, a target of TZDs, is expressed abundantly in adipocytes, suggesting an important role for this tissue in the etiology and treatment of IR. Targeted deletion of PPARgamma in adipose tissue resulted in marked adipocyte hypocellularity and hypertrophy, elevated levels of plasma free fatty acids and triglyceride, and decreased levels of plasma leptin and ACRP30. In addition, increased hepatic glucogenesis and IR were observed. Despite these defects, blood glucose, glucose and insulin tolerance, and insulin-stimulated muscle glucose uptake were all comparable to those of control mice. However, targeted mice were significantly more susceptible to high-fat diet-induced steatosis, hyperinsulinemia, and IR. Surprisingly, TZD treatment effectively reversed liver IR, whereas it failed to lower plasma free fatty acids. These results suggest that syndrome X may be comprised of separable PPARgamma-dependent components whose origins and therapeutic sites may reside in distinct tissues.