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1.
ISA Trans ; 132: 146-154, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35764425

RESUMO

Autonomous systems and the Internet of Things (IoT) have become more sophisticated research areas and entered successfully into various daily living activities such as smart homes & buildings, autonomous cars, drones, robots, etc. A crucial and essential aspect of these systems is the precision and accuracy of the decision-making process, i.e., the decision support system. Likewise, developing a completely autonomous system is an open research problem. This paper proposes a computational intelligence-based prediction and communication mechanism for the independent system where IoT is used as a data collection tool. Initially, energy gauge (EG) devices collect helpful information about neighboring devices in the IoT networks. Then, information about the potential relaying devices is broadcasted by the concerned EG device, which uses every member device to adjust routing path(s) in the autonomous system. Furthermore, every EG device has an embedded computational intelligent decision support system that is used to precisely predict the criticality of a neighboring device (preferably relay) in the autonomous systems. Therefore, every device must ensure data transmission via the most reliable path(s), i.e., avoiding critical devices if possible. A device is assumed critical if either its residual energy or received signal strength indicator value is less than the defined threshold values for the autonomous systems. Additionally, the proposed mechanism has ensured a uniform traffic distribution of the transmitted packets in the autonomous system. The operational applicability of the proposed computational intelligence-enabled prediction mechanism in the autonomous system is verified by comparing it with the existing approaches. Simulation results show that the proposed scheme has enhanced the accuracy of the concerned autonomous systems more than other schemes.

2.
JCI Insight ; 6(18)2021 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-34403370

RESUMO

Venous valve (VV) failure causes chronic venous insufficiency, but the molecular regulation of valve development is poorly understood. A primary lymphatic anomaly, caused by mutations in the receptor tyrosine kinase EPHB4, was recently described, with these patients also presenting with venous insufficiency. Whether the venous anomalies are the result of an effect on VVs is not known. VV formation requires complex "organization" of valve-forming endothelial cells, including their reorientation perpendicular to the direction of blood flow. Using quantitative ultrasound, we identified substantial VV aplasia and deep venous reflux in patients with mutations in EPHB4. We used a GFP reporter in mice to study expression of its ligand, ephrinB2, and analyzed developmental phenotypes after conditional deletion of floxed Ephb4 and Efnb2 alleles. EphB4 and ephrinB2 expression patterns were dynamically regulated around organizing valve-forming cells. Efnb2 deletion disrupted the normal endothelial expression patterns of the gap junction proteins connexin37 and connexin43 (both required for normal valve development) around reorientating valve-forming cells and produced deficient valve-forming cell elongation, reorientation, polarity, and proliferation. Ephb4 was also required for valve-forming cell organization and subsequent growth of the valve leaflets. These results uncover a potentially novel cause of primary human VV aplasia.


Assuntos
Efrina-B2/genética , Receptor EphB4/genética , Receptor EphB4/metabolismo , Válvulas Venosas/anormalidades , Válvulas Venosas/embriologia , Animais , Aorta/ultraestrutura , Comunicação Celular , Polaridade Celular , Proliferação de Células , Conexina 43/metabolismo , Conexinas/metabolismo , Endotélio , Efrina-B2/metabolismo , Humanos , Camundongos , Camundongos Knockout , Mutação , Fenótipo , Ultrassonografia , Malformações Vasculares/diagnóstico por imagem , Malformações Vasculares/genética , Insuficiência Venosa/diagnóstico por imagem , Válvulas Venosas/diagnóstico por imagem , Proteína alfa-4 de Junções Comunicantes
3.
J Healthc Eng ; 2021: 1686946, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34306586

RESUMO

In recent decades, the Internet of flying networks has made significant progress. Several aerial vehicles communicate with one another to form flying ad hoc networks. Unmanned aerial vehicles perform a wide range of tasks that make life easier for humans. However, due to the high frequency of mobile flying vehicles, network problems such as packet loss, latency, and perhaps disrupted channel links arise, affecting data delivery. The use of UAV-enabled IoT in sports has changed the dynamics of tracking and working on player safety. WBAN can be merged with aerial vehicles to collect data regarding health and transfer it to a base station. Furthermore, the unbalanced energy usage of flying things will result in earlier mission failure and a rapid decline in network lifespan. This study describes the use of each UAV's residual energy level to ensure a high level of safety using an ant-based routing technique called AntHocNet. In health care, the use of IoT-assisted aerial vehicles would increase operational performance, surveillance, and automation optimization to provide a smart application of flying IoT. Apart from that, aerial vehicles can be used in remote communication for treatment, medical equipment distribution, and telementoring. While comparing routing algorithms, simulation findings indicate that the proposed ant-based routing protocol is optimal.


Assuntos
Formigas , Algoritmos , Animais , Humanos , Monitorização Fisiológica , Saúde Pública , Tecnologia sem Fio
4.
Psychosom Med ; 79(4): 426-433, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27879552

RESUMO

OBJECTIVE: Few studies have focused on the effect of complicated grief-unresolved and prolonged grief-on the neuroendocrine systems. The present study examined the association of complicated grief and normal grief with the diurnal cortisol patterns in a large population-based study. METHODS: This study was set in the Rotterdam Study and comprised 2084 persons aged older than 55 years (mean [SD] age, 64.9 [5.5] years). Participants were assessed with the Complicated Grief Inventory and classified into no grief (n = 1922), normal grief (n = 131), or complicated grief (n = 31) if they experienced the loss in the past 2 years. Saliva samples were collected to measure cortisol levels. Morning cortisol and summary measures (area under the curve and the slope) were studied to account for the diurnal pattern of cortisol. Persons with depressive disorders were excluded, and analyses were additionally adjusted for depressive symptoms. RESULTS: Compared to normal grievers, participants with complicated grief showed lower levels of morning cortisol (11.26 vs 15.51 nmol/L; difference, -4.24; 95% confidence interval [CI] = -7.87 to -0.62; p = .022), and lower levels of overall diurnal cortisol (6.89 vs 8.98 nmol/L; difference, -2.09; 95% CI = -3.81 to -0.37; p = .017). No difference was observed in slope between both groups. Participants with complicated grief also showed lower levels of morning cortisol than the nongrievers (11.26 vs 14.71; difference, -3.46; 95% CI = -6.78 to -0.13; p = .042). In contrast, cortisol secretion patterns did not differ between persons with normal grief and nongrieving controls. CONCLUSIONS: Participants with complicated grief showed low levels of morning cortisol and low overall diurnal cortisol levels characteristic for a chronic stress reaction.


Assuntos
Ritmo Circadiano , Pesar , Hidrocortisona/análise , Idoso , Ritmo Circadiano/fisiologia , Feminino , Humanos , Hidrocortisona/fisiologia , Masculino , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica , Fatores de Tempo
5.
J Am Coll Cardiol ; 67(4): 420-431, 2016 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-26821631

RESUMO

BACKGROUND: Use of blood oxygenation level-dependent cardiovascular magnetic resonance (BOLD-CMR) to assess perfusion in the lower limb has been hampered by poor reproducibility and a failure to reliably detect post-revascularization improvements in patients with critical limb ischemia (CLI). OBJECTIVES: This study sought to develop BOLD-CMR as an objective, reliable clinical tool for measuring calf muscle perfusion in patients with CLI. METHODS: The calf was imaged at 3-T in young healthy control subjects (n = 12), age-matched control subjects (n = 10), and patients with CLI (n = 34). Signal intensity time curves were generated for each muscle group and curve parameters, including signal reduction during ischemia (SRi) and gradient during reactive hyperemia (Grad). BOLD-CMR was used to assess changes in perfusion following revascularization in 12 CLI patients. Muscle biopsies (n = 28), obtained at the level of BOLD-CMR measurement and from healthy proximal muscle of patients undergoing lower limb amputation (n = 3), were analyzed for capillary-fiber ratio. RESULTS: There was good interuser and interscan reproducibility for Grad and SRi (all p < 0.0001). The ischemic limb had lower Grad and SRi compared with the contralateral asymptomatic limb, age-matched control subjects, and young control subjects (p < 0.001 for all comparisons). Successful revascularization resulted in improvement in Grad (p < 0.0001) and SRi (p < 0.0005). There was a significant correlation between capillary-fiber ratio (p < 0.01) in muscle biopsies from amputated limbs and Grad measured pre-operatively at the corresponding level. CONCLUSIONS: BOLD-CMR showed promise as a reliable tool for assessing perfusion in the lower limb musculature and merits further investigation in a clinical trial.


Assuntos
Angioplastia/métodos , Isquemia/sangue , Perna (Membro)/irrigação sanguínea , Imageamento por Ressonância Magnética/métodos , Oxigênio/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Progressão da Doença , Feminino , Seguimentos , Humanos , Isquemia/diagnóstico , Isquemia/terapia , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Prognóstico , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Ultrassonografia Doppler Dupla , Adulto Jovem
6.
BMC Genet ; 15: 159, 2014 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-25543667

RESUMO

BACKGROUND: It has been well-established, both by population genetics theory and direct observation in many organisms, that increased genetic diversity provides a survival advantage. However, given the limitations of both sample size and genome-wide metrics, this hypothesis has not been comprehensively tested in human populations. Moreover, the presence of numerous segregating small effect alleles that influence traits that directly impact health directly raises the question as to whether global measures of genomic variation are themselves associated with human health and disease. RESULTS: We performed a meta-analysis of 17 cohorts followed prospectively, with a combined sample size of 46,716 individuals, including a total of 15,234 deaths. We find a significant association between increased heterozygosity and survival (P = 0.03). We estimate that within a single population, every standard deviation of heterozygosity an individual has over the mean decreases that person's risk of death by 1.57%. CONCLUSIONS: This effect was consistent between European and African ancestry cohorts, men and women, and major causes of death (cancer and cardiovascular disease), demonstrating the broad positive impact of genomic diversity on human survival.


Assuntos
Polimorfismo de Nucleotídeo Único , Estudo de Associação Genômica Ampla , Heterozigoto , Humanos , Mortalidade , Modelos de Riscos Proporcionais
7.
Carcinogenesis ; 29(4): 738-46, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18281251

RESUMO

Basal cell carcinoma (BCC) of the skin is a highly compact, non-metastatic epithelial tumour type that may arise from the aberrant propagation of epidermal or progenitor stem cell (SC) populations. Increased expression of GLI1 is a common feature of BCC and is linked to the induction of epidermal SC markers in immortalized N/Tert-1 keratinocytes. Here, we demonstrate that GLI1 over-expression is linked to additional SC characteristics in N/Tert-1 cells including reduced epidermal growth factor receptor (EGFR) expression and compact colony formation that is associated with repressed extracellular signal-regulated kinase (ERK) activity. Colony formation and repressed ERK activity remain evident when EGFR is increased exogenously to the basal levels in GLI1 cells revealing that ERK is additionally inhibited downstream of the receptor. Exposure to epidermal growth factor (EGF) to increase ERK activity and promote migration negates GLI1 colony formation with cells displaying an elongated, fibroblast-like morphology. However, as determined by Snail messenger RNA and E-cadherin protein expression this is not associated with epithelial-mesenchymal transition (EMT), and GLI1 actually represses induction of the EMT marker vimentin in EGF-stimulated cells. Instead, live cell imaging revealed that the elongated morphology of EGF/GLI1 keratinocytes stems from their being 'stretched' due to migrating cells displaying inefficient cell-cell detachment and impaired tail retraction. Taken together, these data suggest that GLI1 opposes EGFR signalling to maintain the epithelial phenotype. Finally, ERK activity was predominantly negative in 13/14 BCCs (superficial/nodular), indicating that GLI1 does not routinely co-operate with ERK to induce the formation of this common skin tumour.


Assuntos
Movimento Celular/fisiologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Queratinócitos/citologia , Queratinócitos/fisiologia , Fatores de Transcrição/metabolismo , Carcinoma Basocelular , Adesão Celular , Divisão Celular , Linhagem Celular Tumoral , Primers do DNA , Células Epidérmicas , Epiderme/fisiologia , Genes Reporter , Humanos , Reação em Cadeia da Polimerase , Neoplasias Cutâneas , Proteína GLI1 em Dedos de Zinco
8.
Stem Cells ; 25(5): 1286-97, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17255524

RESUMO

We showed previously that primary keratinocytes selected for low desmoglein 3 (Dsg3) expression levels exhibited increased colony-forming efficiency and heightened proliferative potential relative to cells with higher Dsg3 expression levels, characteristics consistent with a more "stem/progenitor cell-like" phenotype. Here, we have confirmed that Dsg3(dim) cells derived from cultured primary human adult keratinocytes have comparability with alpha(6)(bri)/CD71(dim) stem cells in terms of colony-forming efficiency. Moreover, these Dsg3(dim) cells exhibit increased reconstituting ability in in vitro organotypic culture on de-epidermalized dermis (DED); they are small, actively cycling cells, and they express elevated levels of various p63 isoforms. In parallel, using the two immortalized keratinocyte cell lines HaCaT and NTERT, we obtained essentially similar though occasionally different findings. Thus, reduced colony-forming efficiency by Dsg3(bri) cells consistently was observed in both cell lines even though the cell cycle profile and levels of p63 isoforms in the bri and dim populations differed between these two cell lines. Dsg3(dim) cells from both immortalized lines produced thicker and better ordered hierarchical structural organization of reconstituted epidermis relative to Dsg3(bri) and sorted control cells. Dsg3(dim) HaCaT cells also show sebocyte-like differentiation in the basal compartment of skin reconstituted after a 4-week organotypic culture. No differences in percentages of side population cells (also a putative marker of stem cells) were detected between Dsg3(dim) and Dsg3(bri) populations. Taken together our data indicate that Dsg3(dim) populations from primary human adult keratinocytes and long-term established keratinocyte lines possess certain stem/progenitor cell-like properties, although the side population characteristic is not one of these features. Disclosure of potential conflicts of interest is found at the end of this article.


Assuntos
Desmogleína 3/metabolismo , Queratinócitos/citologia , Queratinócitos/metabolismo , Células-Tronco/citologia , Células 3T3 , Animais , Antígenos CD/metabolismo , Caderinas/metabolismo , Ciclo Celular , Linhagem Celular , Linhagem Celular Transformada , Núcleo Celular/metabolismo , Proliferação de Células , Tamanho Celular , Ensaio de Unidades Formadoras de Colônias , Citoplasma/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Desmossomos/metabolismo , Epitélio/metabolismo , Citometria de Fluxo , Regulação da Expressão Gênica , Humanos , Camundongos , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Receptores da Transferrina/metabolismo , Transativadores/genética , Transativadores/metabolismo , Fatores de Transcrição , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo
9.
J Invest Dermatol ; 122(6): 1503-9, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15175043

RESUMO

Sonic hedgehog (Shh) binds to its receptor patched (PTCH), leading to the activation and repression of target genes via the GLI family of zinc-finger transcription factors. Deregulation of the Shh pathway is associated with basal cell carcinoma (BCC) due to upregulation of GLI1 and GLI2. We recently demonstrated a positive feedback loop between GLI1 and GLI2, which revealed that GLI1 may be a direct target of GLI2. Using band shift and luciferase reporter assays, we now show that GLI2 binds the GLI-binding consensus sequence in the GLI1 promoter. These data suggest that GLI2 directly activates GLI1 and that retrovirally expressed GLI2 induces expression of endogenous GLI1 in human primary keratinocytes. Finally, using in situ hybridization, we show that GLI2 is expressed in the interfollicular epidermis and the outer root sheath of hair follicles in normal skin as well as in BCC tumor islands. These results suggest an important role for GLI2 in regulating epidermal proliferation and skin tumorigenesis.


Assuntos
Carcinoma Basocelular/fisiopatologia , Epiderme/fisiologia , Proteínas Oncogênicas/genética , Neoplasias Cutâneas/fisiopatologia , Fatores de Transcrição/genética , Sequência de Bases , Carcinoma Basocelular/patologia , Linhagem Celular , Células Epidérmicas , Regulação Neoplásica da Expressão Gênica , Folículo Piloso/fisiologia , Humanos , Queratinócitos/citologia , Queratinócitos/fisiologia , Fatores de Transcrição Kruppel-Like , Dados de Sequência Molecular , Proteínas Nucleares , Proteínas Oncogênicas/metabolismo , Regiões Promotoras Genéticas/fisiologia , Neoplasias Cutâneas/patologia , Transativadores , Fatores de Transcrição/metabolismo , Transfecção , Proteína GLI1 em Dedos de Zinco , Proteína Gli2 com Dedos de Zinco
10.
J Invest Dermatol ; 122(5): 1180-7, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15140221

RESUMO

Sonic hedgehog (Hh) signaling plays a key role in epidermal development and skin cancer. Mutational inactivation of the tumor suppressor gene patched (PTCH) leads to constitutive activation of the Hh signaling pathway, resulting in activation of target gene transcription by the zinc finger transcription factors GLI1 and GLI2. Recent experiments in mice point to GLI2 as the key mediator of Hh signaling in skin. We have concentrated on the identification of candidate mediators of GLI2 function in the human epidermis. We show here that the forkhead/winged-helix domain transcription factor FOXE1 is likely to be a direct GLI2 target gene. The kinetics of FOXE1 induction are similar to the known direct target PTCH, and a 2.5 kb upstream fragment containing five GLI-binding sites activates transcription in a reporter assay. We show by in situ hybridization that FOXE1 is expressed in the outer root sheath of the hair follicle, where murine Gli2 is also expressed. FOXE1 expression is also found in basal keratinocytes of the human epidermis and basal cell carcinoma (BCC). These data point to a putative role of FOXE1 in mediating Hh signaling in the human epidermis downstream of GLI2.


Assuntos
Carcinoma Basocelular/fisiopatologia , Proteínas de Ligação a DNA/genética , Epiderme/fisiopatologia , Proteínas Repressoras/genética , Neoplasias Cutâneas/fisiopatologia , Fatores de Transcrição/metabolismo , Proteínas de Ligação a DNA/metabolismo , Células Epidérmicas , Fatores de Transcrição Forkhead , Regulação Neoplásica da Expressão Gênica , Proteínas Hedgehog , Humanos , Hibridização In Situ , Queratinócitos/fisiologia , Fatores de Transcrição Kruppel-Like , Proteínas Nucleares , Regiões Promotoras Genéticas , RNA Mensageiro/análise , Proteínas Repressoras/metabolismo , Transativadores/metabolismo , Transcrição Gênica/fisiologia , Proteína Gli2 com Dedos de Zinco
11.
Oncogene ; 23(6): 1263-74, 2004 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-14691458

RESUMO

In stratified epidermis, activation of the Hh/Gli signal transduction pathway has been implicated in the control of cell proliferation and tumorigenesis. The zinc-finger transcription factor Gli2 has been identified as critical mediator of the Hh signal at the distal end of the pathway, but the molecular mechanisms by which Gli2 regulates cell proliferation or induces epidermal malignancies such as basal cell carcinoma are still unclear. Here, we provide evidence for a role of human GLI2 in antagonizing contact inhibition and epidermal differentiation. We show by gene expression profiling that activation of the GLI2 oncogene in human keratinocytes activates the transcription of a number of genes involved in cell cycle progression such as E2F1, CCND1, CDC2 and CDC45L, while it represses genes associated with epidermal differentiation. Analysis of the proliferative effect of GLI2 revealed that GLI2 is able to induce G1-S phase progression in contact-inhibited keratinocytes. Detailed time-course experiments identified E2F1 as early transcriptional target of GLI2. Further, we show that GLI2 expression in human keratinocytes results in a marked downregulation of epidermal differentiation markers. The data suggest a role for GLI2 in Hh-induced epidermal neoplasia by opposing epithelial cell cycle arrest signals and epidermal differentiation.


Assuntos
Ciclo Celular/fisiologia , Diferenciação Celular/fisiologia , Inibição de Contato/fisiologia , Queratinócitos/citologia , Fatores de Transcrição/genética , Sequência de Bases , Linhagem Celular , Transformação Celular Neoplásica , Primers do DNA , Células Epidérmicas , Epiderme/efeitos dos fármacos , Epiderme/fisiologia , Humanos , Queratinócitos/fisiologia , Fatores de Transcrição Kruppel-Like , Proteínas Nucleares , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/fisiologia , Proteína Gli2 com Dedos de Zinco , Dedos de Zinco/genética , Dedos de Zinco/fisiologia
12.
Cancer Res ; 63(15): 4692-7, 2003 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-12907651

RESUMO

Activation of the Sonic hedgehog signaling pathway, primarily through mutational inactivation of the PTCH1 gene, is associated with the development of basal cell carcinoma (BCC). Gli1, a member of the Gli family of transcription factors, is expressed in BCC and in transgenic mice targeted expression of Gli1 in basal keratinocytes leads to BCC development. In addition to BCC, previous studies have shown that Gli1 is expressed in the outer root sheath (ORS) of the hair follicle but is absent in interfollicular epidermis. In this study, we have characterized the expression pattern of two protein kinase C (PKC) isoforms expressed in BCC and hair follicles. We have then used reporter assays to investigate the effects of these isoforms on Gli1 transcriptional activity. We report that in BCC sections, PKCalpha but not PKCdelta was weakly expressed in the epidermis, whereas in the hair follicle, PKCalpha was expressed in the ORS and PKCdelta in the inner root sheath. In contrast, neither PKCalpha nor PKCdelta was expressed in BCC tumor islands, although both isoforms were often expressed in the surrounding stroma. In mammalian 293T cells, coexpression of constitutively active PKCalpha reduced the activity of Gli1 in a dose-dependent manner, whereas constitutively active PKCdelta increased the activity of Gli1, although this required higher expression levels. Regulation of mutant Gli1 protein localized exclusively to the nucleus was similar to that of the wild-type protein, indicating that nuclear-cytoplasmic shuttling is not a determinant of Gli1 control by either PKC isoform. Furthermore, PKC regulation of Gli1 did not involve activation of mitogen-activated protein kinase signaling. Finally, we show that exogenous Gli1 does not alter the expression of PKCalpha in human primary keratinocytes, suggesting that loss of this isoform in BCC is not via Hedgehog signaling. As BCCs have been proposed to originate from the ORS, loss of PKCalpha expression may be relevant to tumor formation; this may, in part, be because of the predicted increase in Gli1 transcriptional activity.


Assuntos
Carcinoma Basocelular/enzimologia , Proteínas Quinases Dependentes de AMP Cíclico/biossíntese , Isoenzimas/biossíntese , Proteínas Oncogênicas/genética , Neoplasias Cutâneas/enzimologia , Fatores de Transcrição/genética , Carcinoma Basocelular/genética , Carcinoma Basocelular/patologia , Subunidades Catalíticas da Proteína Quinase Dependente de AMP Cíclico , Proteínas Quinases Dependentes de AMP Cíclico/genética , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Folículo Piloso , Humanos , Isoenzimas/genética , Isoenzimas/metabolismo , Isoenzimas/fisiologia , Queratinócitos/enzimologia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Transativadores , Ativação Transcricional , Proteína GLI1 em Dedos de Zinco
13.
Oncogene ; 21(36): 5529-39, 2002 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-12165851

RESUMO

Transgenic mouse models have provided evidence that activation of the zinc-finger transcription factor GLI1 by Hedgehog (Hh)-signalling is a key step in the initiation of the tumorigenic programme leading to Basal Cell Carcinoma (BCC). However, the downstream events underlying Hh/GLI-induced BCC development are still obscure. Using in vitro model systems to analyse the effect of Hh/GLI-signalling in human keratinocytes, we identified a positive feedback mechanism involving the zinc finger transcription factors GLI1 and GLI2. Expression of GLI1 in human keratinocytes induced the transcriptional activator isoforms GLI2alpha and GLI2beta. Both isoforms were also shown to be expressed at elevated levels in 21 BCCs compared to normal skin. Detailed time course experiments monitoring the transcriptional response of keratinocytes either to GLI1 or to GLI2 suggest that GLI1 is a direct target of GLI2, while activation of GLI2 by GLI1 is likely to be indirect. Furthermore, expression of either GLI2 or GLI1 led to an increase in DNA-synthesis in confluent human keratinocytes. Taken together, these results suggest an important role of the positive GLI1-GLI2 feedback loop in Hh-mediated epidermal cell proliferation.


Assuntos
Carcinoma Basocelular/metabolismo , Retroalimentação Fisiológica/fisiologia , Proteínas Oncogênicas/fisiologia , Neoplasias Cutâneas/metabolismo , Fatores de Transcrição/fisiologia , Fosfatase Alcalina/metabolismo , Western Blotting , Bromodesoxiuridina , Carcinoma Basocelular/genética , Primers do DNA/química , DNA de Neoplasias/biossíntese , Ativação Enzimática , Citometria de Fluxo , Proteínas de Fluorescência Verde , Proteínas Hedgehog , Humanos , Queratinócitos/metabolismo , Fatores de Transcrição Kruppel-Like , Luciferases/metabolismo , Proteínas Luminescentes/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Nucleares , Receptores Patched , Reação em Cadeia da Polimerase , RNA/metabolismo , Receptores de Superfície Celular , Retroviridae/genética , Transdução de Sinais , Neoplasias Cutâneas/genética , Transativadores/fisiologia , Transcrição Gênica , Transfecção , Proteína GLI1 em Dedos de Zinco , Proteína Gli2 com Dedos de Zinco , Dedos de Zinco
14.
Saudi Med J ; 19(1): 41-44, 1998 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27701513

RESUMO

Full text is available as a scanned copy of the original print version.

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