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1.
Cells ; 13(2)2024 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-38247870

RESUMO

Regenerative medicine (RM) has emerged as a promising and revolutionary solution to address a range of unmet needs in healthcare, including ophthalmology. Moreover, RM takes advantage of the body's innate ability to repair and replace pathologically affected tissues. On the other hand, despite its immense promise, RM faces challenges such as ethical concerns, host-related immune responses, and the need for additional scientific validation, among others. The primary aim of this review is to present a high-level overview of current strategies in the domain of RM (cell therapy, exosomes, scaffolds, in vivo reprogramming, organoids, and interspecies chimerism), centering around the field of ophthalmology. A search conducted on clinicaltrials.gov unveiled a total of at least 209 interventional trials related to RM within the ophthalmological field. Among these trials, there were numerous early-phase studies, including phase I, I/II, II, II/III, and III trials. Many of these studies demonstrate potential in addressing previously challenging and degenerative eye conditions, spanning from posterior segment pathologies like Age-related Macular Degeneration and Retinitis Pigmentosa to anterior structure diseases such as Dry Eye Disease and Limbal Stem Cell Deficiency. Notably, these therapeutic approaches offer tailored solutions specific to the underlying causes of each pathology, thus allowing for the hopeful possibility of bringing forth a treatment for ocular diseases that previously seemed incurable and significantly enhancing patients' quality of life. As advancements in research and technology continue to unfold, future objectives should focus on ensuring the safety and prolonged viability of transplanted cells, devising efficient delivery techniques, etc.


Assuntos
Oftalmologia , Humanos , Medicina Regenerativa , Qualidade de Vida , Olho , Terapia Baseada em Transplante de Células e Tecidos
2.
Hisp Health Care Int ; : 15404153231212659, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37936370

RESUMO

Colorectal cancer (CRC) is a leading cause of cancer death in the US. Screening by fecal immunochemical test (FIT) is a strategy to lower CRC rates. Unfortunately, only half of patients with an abnormal FIT result complete the follow-up colonoscopy, an essential component of screening. We used virtual Boot Camp Translation (BCT), to elicit input from partners to develop messaging/materials to motivate patients to complete a follow-up colonoscopy. Participants were Hispanic, ages 50 to 75 years, and Spanish-speaking. All materials were developed in English and Spanish. The first meeting included expert presentations that addressed colorectal health. The two follow-up sessions obtained feedback on messaging/materials developed based on themes from the first meeting. Ten participants attended the first meeting and eight attended the follow-up sessions. The two key barriers to follow-up colonoscopy after abnormal FIT noted by participants were (a) lack of colonoscopy awareness and (b) fear of the colonoscopy procedure. We learned that participants valued simple messaging to increase knowledge and alleviate concerns, patient-friendly outreach materials, and increased access to health information. Using virtual BCT, we included participant feedback to design culturally relevant health messages to promote follow-up colonoscopy after abnormal fecal testing among Hispanic patients served by community clinics.

3.
JMIR Cancer ; 9: e43024, 2023 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-37561562

RESUMO

BACKGROUND: Appropriate annual screenings for colorectal cancer (CRC) are an essential preventive measure for the second-leading cause of cancer-related death in the United States. Studies have shown that CRC screening rates are influenced by various social determinants of health (SDOH) factors, including race, ethnicity, and geography. According to 2018 national data, participation in screening is lowest among Hispanic or Latinx individuals (56.1%). At an urban Federally Qualified Health Center, a quality improvement project was conducted to evaluate a texting program with a motivational fotonovela-a short narrative comic. Fotonovelas have previously been used in programs to improve knowledge of cervical cancer and human papillomavirus, vaccinations, and treatments for depression. OBJECTIVE: This study aimed to encourage compliance with fecal immunochemical test (FIT) screening. Patient engagement involved a texting program with fotonovelas informed by behavior change techniques. This study sought to understand the qualitative characteristics of patient motivation, intention, and barriers to completing their screening. METHODS: A total of 5241 English-speaking or Spanish-speaking Federally Qualified Health Center patients aged 50 to 75 years were randomized to either intervention (a 4-week tailored 2-way texting program with a fotonovela comic) or usual care (an SMS text message reminder and patient navigator phone call). The texting vendor used a proprietary algorithm to categorize patients in the intervention group into SDOH bands based on their home addresses (high impact=high social needs and low impact=low social needs). Over 4 weeks, patients were texted questions about receiving and returning their FIT, what barriers they may be experiencing, and their thoughts about the fotonovela. RESULTS: The SDOH index analysis showed that most of the patient population was in the SDOH band categories of high impact (555/2597, 21.37%) and very high impact (1416/2597, 54.52%). Patients sent 1969 total responses to the texting system. Thematic analysis identified 3 major themes in these responses: messages as a reminder, where patients reported that they were motivated to return the FIT and had already done so or would do so as soon as possible; increasing patients' understanding of screening importance, where patients expressed an increased knowledge about the purpose and importance of the FIT; and expressing barriers, where patients shared reasons for not completing the FIT. CONCLUSIONS: The texting program and fotonovela engaged a subset of patients in each SDOH band, including the high and very high impact bands. Creating culturally tailored messages can encourage patient engagement for accepting the content of the messaging, confirming intentions to complete their FIT, and sharing insights about barriers to behavior change. To better support all patients across the continuum of care with CRC screening, it is important to continue to develop and assess strategies that engage patients who did not return their home-mailed FIT.

4.
BMC Gastroenterol ; 23(1): 179, 2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37221503

RESUMO

INTRODUCTION: In partnership with a federally qualified health center (FQHC), an adapted virtual version of boot camp translation (BCT) was used to elicit input from Spanish-speaking Latino patients and staff to develop messaging and patient education materials for follow-up colonoscopy after abnormal fecal testing. We describe how we adapted an existing in-person BCT process to be delivered virtually and present evaluations from participants on the virtual format. METHODS: Three virtual BCT sessions were facilitated by bilingual staff and conducted via Zoom. These sessions included introductions and discussions on colorectal cancer (CRC), CRC screening, and gathered feedback from participants on draft materials. Ten adults were recruited from the FQHC. A research team member from the FQHC served as the point of contact (POC) for all participants and offered Zoom introductory sessions and/or technology support before and during the sessions. Following the third session, participants were invited to complete an evaluation form about their virtual BCT experience. Using a 5-point Likert Scale (where 5 = strongly agree), questions focused on session utility, group comfort level, session pacing, and overall sense of accomplishment. RESULTS: Average scores ranged from 4.3 to 5.0 indicating strong support towards the virtual BCT sessions. Additionally, our study emphasized the importance of a POC to provide technical support to participants throughout the process. Using this approach, we successfully incorporated feedback from participants to design culturally relevant materials to promote follow-up colonoscopy. CONCLUSION: We recommend ongoing public health emphasis on the use of virtual platforms for community engaged work.


Assuntos
Detecção Precoce de Câncer , Neoplasias , Adulto , Humanos , Colonoscopia , Traduções
6.
JMIR Cancer ; 9: e39645, 2023 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-36881466

RESUMO

BACKGROUND: Colorectal cancer (CRC) is currently the second leading cause of cancer-related deaths in the United States; however, it is mostly preventable with appropriate screening and is often treatable when detected at early stages. Many patients enrolled in an urban Federally Qualified Health Center (FQHC) clinic were found to be past due for CRC screening. OBJECTIVE: This study described a quality improvement (QI) project to improve CRC screening rates. This project used bidirectional texting with fotonovela comics and natural language understanding (NLU) to encourage patients to mail fecal immunochemical test (FIT) kits back to the FQHC. METHODS: The FQHC mailed FIT kits to 11,000 unscreened patients in July 2021. Consistent with the usual care, all patients received 2 text messages and a patient navigator call within the first month of mailing. As part of a QI project, 5241 patients who did not return their FIT kit within 3 months, aged 50-75 years, and spoke either English or Spanish were randomized to either usual care (no further intervention) or intervention (4-week texting campaign with a fotonovela comic and remailing kits if requested) groups. The fotonovela was developed to address known barriers to CRC screening. The texting campaign used NLU to respond to patients' texts. A mixed methods evaluation used data from SMS text messages and electronic medical records to understand the impact of the QI project on CRC screening rates. Open-ended text messages were analyzed for themes, and interviews were completed with a convenience sample of patients to understand barriers to screening and impact of the fotonovela. RESULTS: Of the 2597 participants, 1026 (39.5%) in the intervention group engaged with bidirectional texting. Participating in bidirectional texting was related to language preference (χ22=11.0; P=.004) and age group (χ22=19.0; P<.001). Of the 1026 participants who engaged bidirectionally, 318 (31%) clicked on the fotonovela. Furthermore, 54% (32/59) of the patients clicked on the fotonovela and responded that they loved it, and 36% (21/59) of patients responded that they liked it. The intervention group was more likely to get screened (487/2597, 18.75%) than those in usual care (308/2644, 11.65%; P<.001), and this pattern held, regardless of demographic subgroup (sex, age, screening history, preferred language, and payer type). Interview data (n=16) indicated that the text messages, navigator calls, and fotonovelas were well received and not unduly invasive. Interviewees noted several important barriers to CRC screening and offered suggestions for reducing barriers and increasing screening. CONCLUSIONS: Texting using NLU and fotonovela is valuable in increasing CRC screening as observed by the FIT return rate for patients in the intervention group. There were patterns in which patients did not engage bidirectionally; future work should investigate how to ensure that populations are not left out of screening campaigns.

7.
J Prim Care Community Health ; 13: 21501319221138423, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36448466

RESUMO

OBJECTIVE: Individuals with an abnormal fecal immunochemical test (FIT) result have an elevated risk of colorectal cancer, and the risk increases if the follow-up colonoscopy is delayed. Of note, rates of follow-up colonoscopy are alarmingly low in federally qualified health centers (FQHCs), US health care settings that serve a majority racial and ethnic minority patient population. We assessed factors associated with colonoscopy after an abnormal FIT result and used chart-abstracted data to assess reasons (including process measures) for lack of follow-up as part of an annual, mailed-FIT outreach program within a large, Latino-serving FQHC. METHODS: As part of the National Institutes of Health-funded PROMPT study, we identified patients with an abnormal FIT result and used logistic regression to assess associations between patient demographics and receipt of follow-up colonoscopy, controlling for patients' preferred language. We report on time (days) to referral and time to colonoscopy. For charts with an abnormal FIT result but no evidence of colonoscopy, we performed a manual abstraction and obtained the reason for the absence of colonoscopy. When there was no evidence of colonoscopy in a patient's electronic health record (EHR), we performed an automated query of the administrative claims database to identify colonoscopy outcomes. RESULTS: We identified 324 patients with abnormal FIT results from July to October 2018. These patients were mostly publicly insured (Medicaid 53.1%, Medicare 14.5%), 81.8% were aged 50 to 64 years, 55.3% were female, 80.3% were Hispanic/Latino, and 67.3% preferred to speak Spanish. We found that 108/324 (33.3%) patients completed colonoscopy within 12 months, and the median time to colonoscopy was 94 days (IQR: 68-176). Common barriers to colonoscopy completion, obtained from chart-abstracted data, were: no documentation following referral to gastrointestinal (GI) specialist or GI consultation (41.6%), no referral to GI specialist following abnormal fecal test (34.2%), and absence of a valid insurance authorization (6.5%). CONCLUSIONS: Multi-level strategies are needed to provide optimal care across the cancer continuum for FQHC patients. In order to reduce the risk of CRC and realize the return on fecal testing investment, concerted system-level efforts are urgently needed to improve rates of follow-up colonoscopy among FQHC patients and redress racial and ethnic disparities in CRC screening outcomes.


Assuntos
Neoplasias Colorretais , Detecção Precoce de Câncer , Estados Unidos , Humanos , Idoso , Feminino , Masculino , Etnicidade , Grupos Minoritários , Medicare , Colonoscopia , Neoplasias Colorretais/diagnóstico
8.
J Asthma Allergy ; 15: 1227-1243, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36071747

RESUMO

Purpose: To evaluate the association between allergic sensitivity and pollen counts in patients with allergic respiratory disease (ARD) and its relationship with atmospheric pollutants. Methods: From 2012 to 2018, we evaluated the sensitivity by skin prick test in ARD patients. The pollen counts were analyzed according to international guidelines (2014-2018). The pollutant and meteorological data were obtained at the same time from AIRE-CDMX websites. We analyzed the association between allergic sensitivity and pollen counts using the χ2 test and stratified by disease allergic rhinitis (AR) and AR with asthma (ARwA), periods (before/after 2015), and pollination seasons (S1:2014-2015), (S2:2015-2016), (S3:2016-2017), (S4:2017-2018). Likewise, we correlated the pollen counts with the concentrations of pollutants using Pearson's correlation. For all analyses, we used SPSS v.21 software, and a p-value <0.05 was considered significant. Results: A total of 520 patients were enrolled, of whom 67.3% had ARwA and 33.7% had AR (p<0.05). The frequency of patients allergic to at least one pollen was higher compared with patients sensitive to indoor allergens (55.3% vs 44.6%, p<0.001). A total of 46.8% of the patients were only sensitive to trees in comparison to other outdoor allergens (p<0.001). The Fraxinus sp. and the Cupressaceae family allergens were approximately two times more frequent than the other tree allergens in both diseases (p<0.05). These pollens doubled their counts since 2015 (p<0.001), which was associated with increases in sensitivity for Fraxinus sp. and the Cupressaceae family compared to previous years (p<0.001). Regarding pollutants, the most significant correlations were with PM10, NO2, PMCO for Fraxinus sp. pollen concentrations in all seasons (p≤0.02). Conclusion: The high increases in pollen counts of the Fraxinus sp. and Cupressaceae family were associated with increases in the frequency of sensitization to these species, and this phenomenon correlated with increases in PM10, NO2, and PMCO.

9.
Cells ; 11(2)2022 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-35053328

RESUMO

Allergen immunotherapy (AIT) is the sole disease-modifying treatment for allergic rhinitis; it prevents rhinitis from progressing to asthma and lowers medication use. AIT against mites, insect venom, and certain kinds of pollen is effective. The mechanism of action of AIT is based on inducing immunological tolerance characterized by increased IL-10, TGF-ß, and IgG4 levels and Treg cell counts. However, AIT requires prolonged schemes of administration and is sometimes associated with adverse reactions. Over the last decade, novel forms of AIT have been developed, focused on better allergen identification, structural modifications to preserve epitopes for B or T cells, post-traductional alteration through chemical processes, and the addition of adjuvants. These modified allergens induce clinical-immunological effects similar to those mentioned above, increasing the tolerance to other related allergens but with fewer side effects. Clinical studies have shown that molecular AIT is efficient in treating grass and birch allergies. This article reviews the possibility of a new AIT to improve the treatment of allergic illness.


Assuntos
Dessensibilização Imunológica/tendências , Adjuvantes Imunológicos/farmacologia , Humanos , Imunização , Peptídeos/imunologia , Proteômica , Resultado do Tratamento
10.
Chemosphere ; 158: 107-15, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27258901

RESUMO

Bioaccumulation of trivalent (CrIII) and hexavalent chromium (CrVI), and its adverse effects were studied in two rotifer species: Brachionus calyciflorus (two different strains), and Lecane quadridentata. Median Lethal Concentration (LC50) at 24 h of both species showed that CrVI is highly toxic: LC50 ranges from 4.7 × 10(-5) to 4 × 10(-6) mg L(-1)), compared with CrIII: LC50 ranges from 0.64 to 1.279 mg L(-1). Using the LC50 as an exposure concentration, and using atomic absorption, the bioconcentration factor (BCF) was obtained and BCFs of rotifers exposed to CrIII are four orders of magnitude lower than BCFs of rotifers exposed to CrVI. The effect of Cr on the elemental composition of the two species of rotifers in their structures by X-ray microanalysis by energy dispersion showed that Cr is found in intoxicated rotifers, but not in control rotifers. The basal immunoreactivity to metallothioneins is greater in B. calyciflorus than L. quadridentata. The immunoreactivity to metallothioneins decreases in B. calyciflorus when is exposed to CrIII, in contrast in L. quadridentata the immunoreactivity to metallothioneins increase when is exposed to CrIII, and the immunoreactivity to CrVI in L. quadridentata decrease. A mechanism is proposed in which the harder lorica of L. quadridentata acts as a barrier and accumulator of CrVI, and allows for attenuating responses like metallothionein production in L. quadridentata. Instead, in B. calyciflorus the lack of a harder lorica allows for deeper penetration of CrVI, and no time to produce attenuating measures.


Assuntos
Cromo/análise , Água Doce/química , Rotíferos/efeitos dos fármacos , Poluentes Químicos da Água/análise , Animais , Microanálise por Sonda Eletrônica , Monitoramento Ambiental , Imuno-Histoquímica , Metalotioneína/análise , Testes de Toxicidade
11.
Yale J Biol Med ; 87(2): 113-26, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24910557

RESUMO

The recent obesity epidemic has imposed significant health, economical, and societal concerns. However, effective preventive and therapeutic strategies are currently lacking, primarily due to a lack of comprehensive understanding of the underlying molecular mechanisms. Recent genome-wide scans of genetic variants, transcriptome, and epigenome have uncovered >50 genetic loci that predispose individuals to obesity and revealed hundreds of genes with altered transcriptional activity and/or epigenetic variations in obesity-related tissues upon various environmental challenges such as high caloric diets, lack of physical activity, and environmental chemicals. These discoveries highlight the importance of genes involved in the control of energy homeostasis and food intake by the central nervous system, as well as genes contributing to lipid metabolism, adipogenesis, fat cell differentiation, and immune response in peripheral tissues, in obesity development. Future studies that are directed to obtain a more comprehensive, systems-level understanding of disease mechanisms and that test novel therapeutic strategies aiming at systems-level normalization of the obesity-related molecular alterations are warranted.


Assuntos
Genômica , Obesidade/genética , Obesidade/fisiopatologia , Biologia de Sistemas , Meio Ambiente , Predisposição Genética para Doença , Humanos , Obesidade/metabolismo , Fatores de Risco
12.
Artigo em Inglês | MEDLINE | ID: mdl-24110888

RESUMO

We present a new framework for image segmentation with statistical shape model enhanced level sets represented as a linear combination of non-Euclidean radial basis functions (RBFs). The shape prior for the level set is represented as a probabilistic map created from the training data and registered with the target image. The new framework has the following advantages: 1) the explicit RBF representation of the level set allows the level set evolution to be represented as ordinary differential equations and reinitialization is no longer required. 2) The non-Euclidean distance RBFs makes it possible to incorporate image information into the basis functions, which results in more accurate and topologically more flexible solutions. Experimental results are presented to demonstrate the advantages of the method, as well as critical analysis of level sets versus the combination of both methods.


Assuntos
Aumento da Imagem , Interpretação de Imagem Assistida por Computador , Reconhecimento Automatizado de Padrão , Algoritmos , Meios de Contraste/química , Mãos/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Funções Verossimilhança , Modelos Estatísticos , Miocárdio/patologia , Probabilidade , Reprodutibilidade dos Testes
13.
Development ; 133(24): 4945-55, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17119020

RESUMO

Members of the T-box transcription factor family (Tbx) are associated with several human syndromes during embryogenesis. Nevertheless, their functions within the developing CNS remain poorly characterized. Tbx20 is expressed by migrating branchiomotor/visceromotor (BM/VM) neurons within the hindbrain during neuronal circuit formation. We examined Tbx20 function in BM/VM cells using conditional Tbx20-null mutant mice to delete the gene in neurons. Hindbrain rhombomere patterning and the initial generation of post-mitotic BM/VM neurons were normal in Tbx20 mutants. However, Tbx20 was required for the tangential (caudal) migration of facial neurons, the lateral migration of trigeminal cells and the trans-median movement of vestibuloacoustic neurons. Facial cell soma migration defects were associated with the coordinate downregulation of multiple components of the planar cell polarity pathway including Fzd7, Wnt11, Prickle1, Vang1 and Vang2. Our study suggests that Tbx20 programs a variety of hindbrain motor neurons for migration, independent of directionality, and in facial neurons is a positive regulator of the non-canonical Wnt signaling pathway.


Assuntos
Nervos Cranianos/embriologia , Neurônios Motores/citologia , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Animais , Axônios/metabolismo , Movimento Celular , Polaridade Celular , Nervos Cranianos/citologia , Desenvolvimento Embrionário/genética , Nervo Facial/citologia , Nervo Facial/embriologia , Perfilação da Expressão Gênica , Camundongos , Camundongos Transgênicos , Neurônios Motores/metabolismo , Mutação , Transdução de Sinais , Nervo Trigêmeo/citologia , Nervo Trigêmeo/embriologia , Nervo Vestibulococlear/citologia , Nervo Vestibulococlear/embriologia , Proteínas Wnt/metabolismo
14.
Science ; 307(5709): 596-600, 2005 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-15681389

RESUMO

Neuronal gene transcription is repressed in non-neuronal cells by the repressor element 1 (RE-1)-silencing transcription factor/neuron-restrictive silencer factor (REST/NRSF) complex. To understand how this silencing is achieved, we examined a family of class-C RNA polymerase II (RNAPII) carboxyl-terminal domain (CTD) phosphatases [small CTD phosphatases (SCPs) 1 to 3], whose expression is restricted to non-neuronal tissues. We show that REST/NRSF recruits SCPs to neuronal genes that contain RE-1 elements, leading to neuronal gene silencing in non-neuronal cells. Phosphatase-inactive forms of SCP interfere with REST/NRSF function and promote neuronal differentiation of P19 stem cells. Likewise, small interfering RNA directed to the single Drosophila SCP unmasks neuronal gene expression in S2 cells. Thus, SCP activity is an evolutionarily conserved transcriptional regulator that acts globally to silence neuronal genes.


Assuntos
Inativação Gênica , Neurônios/fisiologia , Fosfoproteínas Fosfatases/metabolismo , Proteínas Repressoras/metabolismo , Fatores de Transcrição/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Diferenciação Celular , Linhagem Celular , Imunoprecipitação da Cromatina , Proteínas de Ligação a DNA/metabolismo , Regulação para Baixo , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Hibridização In Situ , Camundongos , Proteínas do Tecido Nervoso/metabolismo , Neurônios/citologia , Proteínas Nucleares , Fosfoproteínas Fosfatases/genética , Fosforilação , Interferência de RNA , Sequências Reguladoras de Ácido Nucleico , Fatores de Transcrição TCF , Proteína 1 Semelhante ao Fator 7 de Transcrição , Tretinoína/farmacologia
15.
Genes Dev ; 19(2): 282-94, 2005 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-15655114

RESUMO

Spinal motor neurons and oligodendrocytes are generated sequentially from a common pool of progenitors termed pMN cells. Olig2 is a bHLH-class transcription factor in pMN cells, but it has remained unclear how its transcriptional activity is modulated to first produce motor neurons and then oligodendrocytes. Previous studies have shown that Olig2 primes pMN cells to become motor neurons by triggering the expression of Ngn2 and Lhx3. Here we show that Olig2 also antagonizes the premature expression of post-mitotic motor neuron genes in pMN cells. This blockade is counteracted by Ngn2, which accumulates heterogeneously in pMN cells, thereby releasing a subset of the progenitors to differentiate and activate expression of post-mitotic motor neuron genes. The antagonistic relationship between Ngn2 and Olig2 is mediated by protein interactions that squelch activity as well as competition for shared DNA-binding sites. Our data support a model in which the Olig2/Ngn2 ratio in progenitor cells serves as a gate for timing proper gene expression during the development of pMN cells: Olig2(high) maintains the pMN state, thereby holding cells in reserve for oligodendrocyte generation, whereas Ngn2(high) favors the conversion of pMN cells into post-mitotic motor neurons.


Assuntos
Diferenciação Celular/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Proteínas de Homeodomínio/biossíntese , Neurônios Motores/metabolismo , Proteínas do Tecido Nervoso/biossíntese , Oligodendroglia/metabolismo , Células-Tronco/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Diferenciação Celular/fisiologia , Embrião de Galinha , Desenvolvimento Embrionário/genética , Desenvolvimento Embrionário/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Proteínas de Homeodomínio/genética , Proteínas com Homeodomínio LIM , Camundongos , Neurônios Motores/citologia , Proteínas do Tecido Nervoso/genética , Fator de Transcrição 2 de Oligodendrócitos , Oligodendroglia/citologia , Fatores de Transcrição
16.
Development ; 131(14): 3295-306, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15201216

RESUMO

The underlying transcriptional mechanisms that establish the proper spatial and temporal pattern of gene expression required for specifying neuronal fate are poorly defined. We have characterized how the Hb9 gene is expressed in developing motoneurons in order to understand how transcription is directed to specific cells within the developing CNS. We found that non-specific general-activator proteins such as E2F and Sp1 are capable of driving widespread low level transcription of Hb9 in many cell types throughout the neural tube; however, their activity is modulated by specific repressor and activator complexes. The general-activators of Hb9 are suppressed from triggering inappropriate transcription by repressor proteins Irx3 and Nkx2.2. High level motoneuron expression is achieved by assembling an enhancesome on a compact evolutionarily-conserved segment of Hb9 located from -7096 to -6896. The ensemble of LIM-HD and bHLH proteins that interact with this enhancer change as motoneuron development progresses, facilitating both the activation and maintenance of Hb9 expression in developing and mature motoneurons. These findings provide direct support for the derepression model of gene regulation and cell fate specification in the neural tube, as well as establishing a role for enhancers in targeting gene expression to a single neuronal subtype in the spinal cord.


Assuntos
Proteínas de Ciclo Celular , Sistema Nervoso Central/embriologia , Elementos Facilitadores Genéticos , Regulação da Expressão Gênica no Desenvolvimento , Neurônios Motores/metabolismo , Animais , Sequência de Bases , Linhagem Celular , Linhagem da Célula , Embrião de Galinha , DNA/metabolismo , Proteínas de Ligação a DNA/metabolismo , Fatores de Transcrição E2F , Eletroporação , Éxons , Proteínas de Fluorescência Verde , Proteína Homeobox Nkx-2.2 , Proteínas de Homeodomínio/metabolismo , Humanos , Imuno-Histoquímica , Proteínas Luminescentes/metabolismo , Camundongos , Camundongos Transgênicos , Modelos Biológicos , Modelos Genéticos , Dados de Sequência Molecular , Crista Neural/embriologia , Neurônios/metabolismo , Proteínas Nucleares , Biossíntese de Proteínas , Homologia de Sequência do Ácido Nucleico , Fator de Transcrição Sp1/metabolismo , Medula Espinal/embriologia , Fatores de Tempo , Fatores de Transcrição/metabolismo , Transcrição Gênica , Transfecção , Transgenes , Proteínas de Peixe-Zebra
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