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1.
Development ; 151(9)2024 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-38587174

RESUMO

The gastrointestinal (GI) tract is complex and consists of multiple organs with unique functions. Rare gene variants can cause congenital malformations of the human GI tract, although the molecular basis of these has been poorly studied. We identified a patient with compound-heterozygous variants in RFX6 presenting with duodenal malrotation and atresia, implicating RFX6 in development of the proximal intestine. To identify how mutations in RFX6 impact intestinal patterning and function, we derived induced pluripotent stem cells from this patient to generate human intestinal organoids (HIOs). We identified that the duodenal HIOs and human tissues had mixed regional identity, with gastric and ileal features. CRISPR-mediated correction of RFX6 restored duodenal identity. We then used gain- and loss-of-function and transcriptomic approaches in HIOs and Xenopus embryos to identify that PDX1 is a downstream transcriptional target of RFX6 required for duodenal development. However, RFX6 had additional PDX1-independent transcriptional targets involving multiple components of signaling pathways that are required for establishing early regional identity in the GI tract. In summary, we have identified RFX6 as a key regulator in intestinal patterning that acts by regulating transcriptional and signaling pathways.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio , Organoides , Fatores de Transcrição de Fator Regulador X , Transativadores , Humanos , Fatores de Transcrição de Fator Regulador X/genética , Fatores de Transcrição de Fator Regulador X/metabolismo , Animais , Proteínas de Homeodomínio/metabolismo , Proteínas de Homeodomínio/genética , Transativadores/metabolismo , Transativadores/genética , Organoides/metabolismo , Organoides/embriologia , Duodeno/metabolismo , Duodeno/embriologia , Intestinos/embriologia , Atresia Intestinal/genética , Células-Tronco Pluripotentes Induzidas/metabolismo , Padronização Corporal/genética , Transdução de Sinais/genética , Mutação/genética
3.
Dev Growth Differ ; 64(7): 347-361, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36053777

RESUMO

Ventx2 is an Antennapedia superfamily/NK-like subclass homeodomain transcription factor best known for its roles in the regulation of early dorsoventral patterning during Xenopus gastrulation and in the maintenance of neural crest multipotency. In this work we characterize the spatiotemporal expression pattern of ventx2 in progenitor cells of the Xenopus respiratory system epithelium. We find that ventx2 is directly induced by BMP signaling in the ventral foregut prior to nkx2-1, the earliest epithelial marker of the respiratory lineage. Functional studies demonstrate that Ventx2 regulates the number of Nkx2-1/Sox9+ respiratory progenitor cells induced during foregut development, the timing and level of surfactant protein gene expression, and proper tracheal-esophageal separation. Our data suggest that Ventx2 regulates the balance of respiratory progenitor cell expansion and differentiation. While the ventx gene family has been lost from the mouse genome during evolution, humans have retained a ventx2-like gene (VENTX). Finally, we discuss how our findings might suggest a possible function of VENTX in human respiratory progenitor cells.


Assuntos
Proteínas de Ligação a DNA , Fatores de Transcrição , Animais , Diferenciação Celular/genética , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Pulmão/metabolismo , Camundongos , Células-Tronco/metabolismo , Tensoativos , Traqueia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas de Xenopus/genética , Proteínas de Xenopus/metabolismo , Xenopus laevis/genética
4.
Compr Rev Food Sci Food Saf ; 21(1): 780-808, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34954889

RESUMO

Shrinkage is a well-documented defect in frozen desserts, yet the root causes and mechanisms remain unknown. Characterized by the loss of volume during storage, shrinkage arose during the mid-twentieth century as production of frozen desserts grew to accommodate a larger market. Early research found that shrinkage was promoted by high protein, solids, and overrun, as well as postproduction factors such as fluctuations in external temperature and pressure. Rather than approaching shrinkage as a cause-and-effect defect as previous approaches have, we employ a physicochemical approach to characterize and understand shrinkage as collapse of the frozen foam caused by destabilization of the dispersed air phase. The interfacial composition and physical properties, as well as the kinetic stability of air cells within the frozen matrix ultimately affect product susceptibility to shrinkage. The mechanism of shrinkage remains unknown, as frozen desserts are highly complex, but is rooted in the physicochemical properties of the frozen foam. Functional ingredients and processing methods that optimize the formation and stabilization of the frozen foam are essential to preventing shrinkage in frozen desserts.


Assuntos
Sorvetes , Congelamento
5.
Aust Educ Res ; 49(3): 595-615, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35370347

RESUMO

The role of interdisciplinarity in achieving authentic and transformative learning outcomes is both contested and complex. At the same time, traditional disciplinary ways of being, doing and knowing have been further tested by the impact of COVID-19 on students, schools and communities. In Tasmania, already experiencing amongst the lowest levels of educational attainment in Australia, the educational implications of COVID-19 have been polarising. Preliminary reports have employed interdisciplinary perspectives to understand how the situation is unfolding. Extremes of privilege and poverty have intensified, with accentuated disadvantage experienced by already vulnerable groups, whilst ingenuity, adaptability and innovation have flourished elsewhere. The spectrum and range of this polarisation yield compelling evidence for the inadequate address of complex societal problems through singular disciplines or institutions. This article explores storied data generated from the intersections of interdisciplinary strategy enacted across three settings: education, creative industries and community-based arts practice. The data derive from two Tasmanian case studies where interdisciplinary collaboration between the education sector, creative industries and community is well established. In subsequent discussion, the multidisciplinary authorship team make and offer meaning from participatory lived experiences of pursuing social justice outcomes prior to and during the COVID-19 pandemic. From this, we posit how lived experiences of interdisciplinarity impact social justice enterprise in times of increasingly complex socio-economic challenge. In addressing these concerns, we elucidate the role interdisciplinarity plays in both enabling and inhibiting social justice imperatives shared across education, creative industry and community-based arts practice immediately prior to and during a global pandemic. In so doing, we elicit the ways interdisciplinary practices, partnerships and priorities recalibrate in response to global challenges.

6.
Proc Natl Acad Sci U S A ; 115(45): E10615-E10624, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30352852

RESUMO

Codevelopment of the lungs and heart underlies key evolutionary innovations in the transition to terrestrial life. Cardiac specializations that support pulmonary circulation, including the atrial septum, are generated by second heart field (SHF) cardiopulmonary progenitors (CPPs). It has been presumed that transcription factors required in the SHF for cardiac septation, e.g., Tbx5, directly drive a cardiac morphogenesis gene-regulatory network. Here, we report instead that TBX5 directly drives Wnt ligands to initiate a bidirectional signaling loop between cardiopulmonary mesoderm and the foregut endoderm for endodermal pulmonary specification and, subsequently, atrial septation. We show that Tbx5 is required for pulmonary specification in mice and amphibians but not for swim bladder development in zebrafish. TBX5 is non-cell-autonomously required for pulmonary endoderm specification by directly driving Wnt2 and Wnt2b expression in cardiopulmonary mesoderm. TBX5 ChIP-sequencing identified cis-regulatory elements at Wnt2 sufficient for endogenous Wnt2 expression domains in vivo and required for Wnt2 expression in precardiac mesoderm in vitro. Tbx5 cooperated with Shh signaling to drive Wnt2b expression for lung morphogenesis. Tbx5 haploinsufficiency in mice, a model of Holt-Oram syndrome, caused a quantitative decrement of mesodermal-to-endodermal Wnt signaling and subsequent endodermal-to-mesodermal Shh signaling required for cardiac morphogenesis. Thus, Tbx5 initiates a mesoderm-endoderm-mesoderm signaling loop in lunged vertebrates that provides a molecular basis for the coevolution of pulmonary and cardiac structures required for terrestrial life.


Assuntos
Evolução Molecular , Coração/embriologia , Pulmão/embriologia , Proteínas com Domínio T/genética , Proteína Wnt2/genética , Animais , Elementos Facilitadores Genéticos , Perfilação da Expressão Gênica , Camundongos , Camundongos Mutantes , Transdução de Sinais , Transcrição Gênica , Peixe-Zebra/embriologia
7.
Development ; 144(7): 1283-1295, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28219948

RESUMO

Digestive system development is orchestrated by combinatorial signaling interactions between endoderm and mesoderm, but how these signals are interpreted in the genome is poorly understood. Here we identified the transcriptomes of Xenopus foregut and hindgut progenitors, which are conserved with mammals. Using RNA-seq and ChIP-seq we show that BMP/Smad1 regulates dorsal-ventral gene expression in both the endoderm and mesoderm, whereas Wnt/ß-catenin acts as a genome-wide toggle between foregut and hindgut programs. Unexpectedly, ß-catenin and Smad1 binding were associated with both transcriptional activation and repression, with Wnt-repressed genes often lacking canonical Tcf DNA binding motifs, suggesting a novel mode of direct repression. Combinatorial Wnt and BMP signaling was mediated by Smad1 and ß-catenin co-occupying hundreds of cis-regulatory DNA elements, and by a crosstalk whereby Wnt negatively regulates BMP ligand expression in the foregut. These results extend our understanding of gastrointestinal organogenesis and of how Wnt and BMP might coordinate genomic responses in other contexts.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Sistema Digestório/metabolismo , Genoma , Proteína Smad1/metabolismo , Transcrição Gênica , Via de Sinalização Wnt/genética , Xenopus laevis/genética , Animais , Sequência de Bases , Padronização Corporal/genética , Cromatina/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Ligação Proteica , Transcriptoma/genética , Xenopus laevis/embriologia , beta Catenina/metabolismo
8.
Genesis ; 57(10): e23329, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31403250

RESUMO

The current Xenopus ORFeome contains ~10,250 validated, full-length cDNA sequences without stop codons from Xenopus laevis and ~3,970 from Xenopus tropicalis cloned into Gateway-compatible entry vectors. To increase the utility of the ORFeome, we have constructed the Gateway-compatible destination vectors pDXTP and pDXTR, which in combination can control the spatial and temporal expression of any open reading frame (ORF). pDXTP receives a promoter/enhancer of interest, which controls the spatial expression of a doxycycline-inducible transcription factor rtTA. pDXTR receives an ORF of interest, which is controlled by a tetracycline response element enabling temporal control of ORF expression via rtTA activation by simple addition of doxycycline to the rearing water at any desired time point. These vectors can be integrated into the genome via well-established microinjection-based SceI, tol2, or phi-C31 transgenesis procedures and contain fluorescence reporters to confirm transgene integration. Cell-autonomous verification of ORF expression occurs via red nuclear fluorescence due to an mCherry-histone H2B fusion protein that is cleaved from the ORF during translation. Function of all essential features of pDXTP and pDXTR has been experimentally validated. pDXTP and pDXTR provide flexible molecular cloning and transgenesis options to accomplish tissue-specific inducible control of ORF expression in transgenic Xenopus.


Assuntos
Vetores Genéticos , Fases de Leitura Aberta , Animais , Doxiciclina/farmacologia , Feminino , Vetores Genéticos/efeitos dos fármacos , Masculino , Fases de Leitura Aberta/efeitos dos fármacos , Elementos de Resposta , Tetraciclina/farmacologia , Transativadores/genética , Fatores de Transcrição/genética , Xenopus/genética , Xenopus laevis/genética
9.
Dev Biol ; 434(1): 121-132, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29217200

RESUMO

A small number of signaling pathways are used repeatedly during organogenesis, and they can have drastically different effects on the same population of cells depending on the embryonic stage. How cellular competence changes over developmental time is not well understood. Here we used Xenopus, mouse, and human pluripotent stem cells to investigate how the temporal sequence of Wnt, BMP, and retinoic acid (RA) signals regulates endoderm developmental competence and organ induction, focusing on respiratory fate. While Nkx2-1+ lung fate is not induced until late somitogenesis stages, here we show that lung competence is restricted by the gastrula stage as a result of Wnt and BMP-dependent anterior-posterior (A-P) patterning. These early Wnt and BMP signals make posterior endoderm refractory to subsequent RA/Wnt/BMP-dependent lung induction. We further mapped how RA modulates the response to Wnt and BMP in a temporal specific manner. In the gastrula RA promotes posterior identity, however in early somite stages of development RA regulates respiratory versus pharyngeal potential in anterior endoderm and midgut versus hindgut potential in posterior endoderm. Together our data suggest a dynamic and conserved response of vertebrate endoderm during organogenesis, wherein early Wnt/BMP/RA impacts how cells respond to later Wnt/BMP/RA signals, illustrating how reiterative combinatorial signaling can regulate both developmental competence and subsequent fate specification.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Endoderma/embriologia , Organogênese/efeitos dos fármacos , Tretinoína/farmacologia , Proteínas Wnt/metabolismo , Proteínas de Xenopus/metabolismo , Animais , Endoderma/citologia , Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/metabolismo , Organogênese/fisiologia , Somitos/citologia , Somitos/embriologia , Especificidade da Espécie , Xenopus laevis
10.
J Dairy Sci ; 102(10): 8691-8695, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421885

RESUMO

Potato pectin has unique molecular characteristics that differentiate it from commercially available pectins sourced from citrus peels or apple pomace, including a higher degree of branching and a higher acetyl content. The objective of this study was to evaluate the ability of potato pectin to stabilize milk proteins at an acidic pH above their isoelectric point, pH 5.5, at which no citrus- or apple-derived pectins are functional. Potato pectin was extracted from raw potato tubers by heating at pH 4.5 and 120°C for 30 min after removing starch solubilized using a dilute HCl solution adjusted to pH 2. The potato pectin was found to have a galacturonic acid content of 17.31 ± 3.29% (wt/wt) and a degree of acetylation of 20.20 ± 0.12%. A portion of the potato pectin was deacetylated by heating it in an alkaline condition. The deacetylation resulted in a galacturonic acid content of 19.12 ± 4.64% (wt/wt) and a degree of acetylation of 3.03 ± 0.03%. Particle size distributions in acidified milk drink (AMD) samples adjusted to pH 5.5 demonstrated that the acetylated and deacetylated potato pectins were capable of inhibiting the aggregation of milk proteins to the largest degree at a pectin concentration of 1.0 and 0.25% (wt/wt), respectively. Pectin molecules that were not bound to milk proteins in these AMD samples were quantified after centrifugally separating milk proteins and pectin bound to them from the serum. We found that, for the acetylated and deacetylated potato pectins, all or approximately half of the pectin molecules were bound to milk proteins at a pectin concentration of 0.25 or 1.0% (wt/wt), respectively. These results suggest that the presence of acetyl groups is a critical factor that determines how potato pectin molecules bind electrostatically to milk protein surfaces, form 3-dimensional structures there, and function as a stabilizer. The present results demonstrate that potato pectin can stabilize milk proteins at pH 5.5 and potentially enable the development of novel AMD products with improved functionality for casein-containing products with moderately acidic pH profiles.


Assuntos
Proteínas do Leite/química , Pectinas/química , Solanum tuberosum/química , Animais , Caseínas/análise , Ácidos Hexurônicos/análise , Concentração de Íons de Hidrogênio , Leite/química , Tubérculos/química , Polissacarídeos/química , Estabilidade Proteica
11.
Molecules ; 24(18)2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31500127

RESUMO

Various bioactive compounds (BCs) often possess poor stability and bioavailability, which makes it difficult for them to exert their potential health benefits. These limitations can be countered by the use of nano-delivery systems (NDSs), such as nanoparticles and nanoemulsions. NDSs can protect BCs against harsh environments during food processing and digestion, and thereby, could enhance the bioavailability of BCs. Although various NDSs have been successfully produced with both synthetic and natural materials, it is necessary to fulfill safety criteria in the delivery materials for food applications. Food-grade materials for the production of NDSs, such as milk proteins and carbohydrates, have received much attention due to their low toxicity, biodegradability, and biocompatibility. Among these, whey proteins-from whey, a byproduct of cheese manufacturing-have been considered as excellent delivery material because of their high nutritional value and various functional properties, such as binding capability to various compounds, gelation, emulsifying properties, and barrier effects. Since the functional and physicochemical properties of whey protein-based NDSs, including size and surface charge, can be key factors affecting the applications of NDSs in food, the objectives of this review are to discuss how manufacturing variables can modulate the functional and physicochemical properties of NDSs and bioavailability of encapsulated BCs to produce efficient NDSs for various BCs.


Assuntos
Sistemas de Liberação de Medicamentos , Proteínas do Leite/química , Nanopartículas/química , Proteínas do Soro do Leite/química , Disponibilidade Biológica , Emulsões/química , Emulsões/uso terapêutico , Manipulação de Alimentos , Géis/química , Humanos , Proteínas do Leite/uso terapêutico , Tamanho da Partícula , Proteínas do Soro do Leite/uso terapêutico
12.
Dev Biol ; 416(1): 187-199, 2016 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-27235146

RESUMO

Temporally and spatially dynamic Wnt and BMP signals are essential to pattern foregut endoderm progenitors that give rise to the liver, pancreas and lungs, but how these two signaling pathways are coordinated in the extracellular space is unknown. Here we identify the transmembrane heparan sulphate proteoglycan Syndecan-4 (Sdc4), as a key regulator of both non-canonical Wnt and BMP signaling in the Xenopus foregut. Foregut-specific Sdc4 depletion results in a disrupted Fibronectin (Fn1) matrix, reduced cell adhesion, and failure to maintain foregut gene expression ultimately leading to foregut organ hypoplasia. Sdc4 is required to maintain robust Wnt/JNK and BMP/Smad1 signaling in the hhex+ foregut progenitors. Pathway analysis suggests that Sdc4 functionally interacts with Fzd7 to promote Wnt/JNK signaling, which maintains foregut identity and cell adhesion. In addition, the Sdc4 ectodomain is required to support Fn1 matrix assembly, which is essential for the robust BMP signaling that promotes foregut gene expression. This work sheds lights on how the extracellular matrix can coordinate different signaling pathways during organogenesis.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Sistema Digestório/embriologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Sindecana-4/metabolismo , Proteínas Wnt/metabolismo , Proteínas de Xenopus/metabolismo , Motivos de Aminoácidos , Animais , Desenvolvimento Embrionário/genética , Matriz Extracelular/metabolismo , Fibronectinas/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Organogênese , Ligação Proteica , Receptores Acoplados a Proteínas G/metabolismo , Xenopus laevis
13.
Nature ; 470(7332): 105-9, 2011 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-21151107

RESUMO

Studies in embryonic development have guided successful efforts to direct the differentiation of human embryonic and induced pluripotent stem cells (PSCs) into specific organ cell types in vitro. For example, human PSCs have been differentiated into monolayer cultures of liver hepatocytes and pancreatic endocrine cells that have therapeutic efficacy in animal models of liver disease and diabetes, respectively. However, the generation of complex three-dimensional organ tissues in vitro remains a major challenge for translational studies. Here we establish a robust and efficient process to direct the differentiation of human PSCs into intestinal tissue in vitro using a temporal series of growth factor manipulations to mimic embryonic intestinal development. This involved activin-induced definitive endoderm formation, FGF/Wnt-induced posterior endoderm pattering, hindgut specification and morphogenesis, and a pro-intestinal culture system to promote intestinal growth, morphogenesis and cytodifferentiation. The resulting three-dimensional intestinal 'organoids' consisted of a polarized, columnar epithelium that was patterned into villus-like structures and crypt-like proliferative zones that expressed intestinal stem cell markers. The epithelium contained functional enterocytes, as well as goblet, Paneth and enteroendocrine cells. Using this culture system as a model to study human intestinal development, we identified that the combined activity of WNT3A and FGF4 is required for hindgut specification whereas FGF4 alone is sufficient to promote hindgut morphogenesis. Our data indicate that human intestinal stem cells form de novo during development. We also determined that NEUROG3, a pro-endocrine transcription factor that is mutated in enteric anendocrinosis, is both necessary and sufficient for human enteroendocrine cell development in vitro. PSC-derived human intestinal tissue should allow for unprecedented studies of human intestinal development and disease.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Células-Tronco Embrionárias/citologia , Células-Tronco Pluripotentes Induzidas/citologia , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Intestinos/citologia , Ativinas/farmacologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Padronização Corporal/efeitos dos fármacos , Técnicas de Cultura de Células , Células Cultivadas , Meios de Cultura/química , Meios de Cultura/farmacologia , Células-Tronco Embrionárias/efeitos dos fármacos , Endoderma/citologia , Endoderma/efeitos dos fármacos , Endoderma/embriologia , Fator 4 de Crescimento de Fibroblastos/farmacologia , Humanos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Intestinos/anatomia & histologia , Intestinos/efeitos dos fármacos , Intestinos/embriologia , Microvilosidades/efeitos dos fármacos , Morfogênese/efeitos dos fármacos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Organogênese/efeitos dos fármacos , Fatores de Tempo , Proteínas Wnt/farmacologia , Proteína Wnt3 , Proteína Wnt3A
14.
Dev Dyn ; 245(1): 47-55, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26264370

RESUMO

BACKGROUND: During primitive hematopoiesis in Xenopus, cebpa and spib expressing myeloid cells emerge from the anterior ventral blood island. Primitive myeloid cells migrate throughout the embryo and are critical for immunity, healing, and development. Although definitive hematopoiesis has been studied extensively, molecular mechanisms leading to the migration of primitive myelocytes remain poorly understood. We hypothesized these cells have specific extracellular matrix modifying and cell motility gene expression. RESULTS: In situ hybridization screens of transcripts expressed in Xenopus foregut mesendoderm at stage 23 identified seven genes with restricted expression in primitive myeloid cells: destrin; coronin actin binding protein, 1a; formin-like 1; ADAM metallopeptidase domain 28; cathepsin S; tissue inhibitor of metalloproteinase-1; and protein tyrosine phosphatase nonreceptor 6. A detailed in situ hybridization analysis revealed these genes are initially expressed in the aVBI but become dispersed throughout the embryo as the primitive myeloid cells become migratory, similar to known myeloid markers. Morpholino-mediated loss-of-function and mRNA-mediated gain-of-function studies revealed the identified genes are downstream of Spib.a and Cebpa, key transcriptional regulators of the myeloid lineage. CONCLUSIONS: We have identified genes specifically expressed in migratory primitive myeloid progenitors, providing tools to study how different gene networks operate in these primitive myelocytes during development and immunity.


Assuntos
Linhagem da Célula/genética , Movimento Celular/genética , Células Mieloides/citologia , Xenopus laevis/genética , Animais , Destrina/genética , Destrina/metabolismo , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Células Mieloides/metabolismo , Inibidor Tecidual de Metaloproteinase-1/genética , Inibidor Tecidual de Metaloproteinase-1/metabolismo
15.
J Biol Chem ; 290(8): 4759-4771, 2015 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-25561725

RESUMO

Bone morphogenetic proteins (BMPs) are antagonized through the action of numerous extracellular protein antagonists, including members from the differential screening-selected gene aberrative in neuroblastoma (DAN) family. In vivo, misregulation of the balance between BMP signaling and DAN inhibition can lead to numerous disease states, including cancer, kidney nephropathy, and pulmonary arterial hypertension. Despite this importance, very little information is available describing how DAN family proteins effectively inhibit BMP ligands. Furthermore, our understanding for how differences in individual DAN family members arise, including affinity and specificity, remains underdeveloped. Here, we present the structure of the founding member of the DAN family, neuroblastoma suppressor of tumorigenicity 1 (NBL1). Comparing NBL1 to the structure of protein related to Dan and Cerberus (PRDC), a more potent BMP antagonist within the DAN family, a number of differences were identified. Through a mutagenesis-based approach, we were able to correlate the BMP binding epitope in NBL1 with that in PRDC, where introduction of specific PRDC amino acids in NBL1 (A58F and S67Y) correlated with a gain-of-function inhibition toward BMP2 and BMP7, but not GDF5. Although NBL1(S67Y) was able to antagonize BMP7 as effectively as PRDC, NBL1(S67Y) was still 32-fold weaker than PRDC against BMP2. Taken together, this data suggests that alterations in the BMP binding epitope can partially account for differences in the potency of BMP inhibition within the DAN family.


Assuntos
Proteína Morfogenética Óssea 2/antagonistas & inibidores , Proteína Morfogenética Óssea 7/antagonistas & inibidores , Peptídeos e Proteínas de Sinalização Intercelular/química , Mutação de Sentido Incorreto , Proteínas/química , Substituição de Aminoácidos , Animais , Proteína Morfogenética Óssea 2/química , Proteína Morfogenética Óssea 2/genética , Proteína Morfogenética Óssea 7/química , Proteína Morfogenética Óssea 7/genética , Células CHO , Proteínas de Ciclo Celular , Cricetinae , Cricetulus , Citocinas , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Mutagênese , Estrutura Terciária de Proteína , Proteínas/genética , Relação Estrutura-Atividade
16.
Dev Dyn ; 244(1): 69-85, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25156440

RESUMO

BACKGROUND: Respiratory system development is regulated by a complex series of endoderm-mesoderm interactions that are not fully understood. Recently Xenopus has emerged as an alternative model to investigate early respiratory system development, but the extent to which the morphogenesis and molecular pathways involved are conserved between Xenopus and mammals has not been systematically documented. RESULTS: In this study, we provide a histological and molecular atlas of Xenopus respiratory system development, focusing on Nkx2.1+ respiratory cell fate specification in the developing foregut. We document the expression patterns of Wnt/ß-catenin, fibroblast growth factor (FGF), and bone morphogenetic protein (BMP) signaling components in the foregut and show that the molecular mechanisms of respiratory lineage induction are remarkably conserved between Xenopus and mice. Finally, using several functional experiments we refine the epistatic relationships among FGF, Wnt, and BMP signaling in early Xenopus respiratory system development. CONCLUSIONS: We demonstrate that Xenopus trachea and lung development, before metamorphosis, is comparable at the cellular and molecular levels to embryonic stages of mouse respiratory system development between embryonic days 8.5 and 10.5. This molecular atlas provides a fundamental starting point for further studies using Xenopus as a model to define the conserved genetic programs controlling early respiratory system development.


Assuntos
Embrião não Mamífero/embriologia , Epistasia Genética/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Metamorfose Biológica/fisiologia , Sistema Respiratório/embriologia , Via de Sinalização Wnt/fisiologia , Animais , Embrião não Mamífero/citologia , Camundongos , Proteínas Nucleares/biossíntese , Proteínas Nucleares/genética , Sistema Respiratório/citologia , Fator Nuclear 1 de Tireoide , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Proteínas de Xenopus , Xenopus laevis , beta Catenina/genética , beta Catenina/metabolismo
17.
Development ; 139(16): 3010-20, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22791896

RESUMO

Embryonic development of the respiratory system is regulated by a series of mesenchymal-epithelial interactions that are only partially understood. Mesenchymal FGF and Wnt2/Wnt2b signaling are implicated in specification of mammalian pulmonary progenitors from the ventral foregut endoderm, but their epistatic relationship and downstream targets are largely unknown. In addition, how wnt2 and wnt2b are regulated in the developing foregut mesenchyme is unknown. We show that the Odd-skipped-related (Osr) zinc-finger transcriptional repressors Osr1 and Osr2 are redundantly required for Xenopus lung specification in a molecular pathway linking foregut pattering by FGFs to Wnt-mediated lung specification and RA-regulated lung bud growth. FGF and RA signals are required for robust osr1 and osr2 expression in the foregut endoderm and surrounding lateral plate mesoderm (lpm) prior to respiratory specification. Depletion of both Osr1 and Osr2 (Osr1/Osr2) results in agenesis of the lungs, trachea and esophagus. The foregut lpm of Osr1/Osr2-depleted embryos fails to express wnt2, wnt2b and raldh2, and consequently Nkx2.1(+) progenitors are not specified. Our data suggest that Osr1/Osr2 normally repress bmp4 expression in the lpm, and that BMP signaling negatively regulates the wnt2b domain. These results significantly advance our understanding of early lung development and may impact strategies to differentiate respiratory tissue from stem cells.


Assuntos
Proteína Morfogenética Óssea 4/metabolismo , Proteínas Repressoras/metabolismo , Proteínas de Xenopus/metabolismo , Xenopus laevis/embriologia , Xenopus laevis/metabolismo , Xenopus/embriologia , Xenopus/metabolismo , Família Aldeído Desidrogenase 1 , Aldeído Oxidase/genética , Aldeído Oxidase/metabolismo , Animais , Sequência de Bases , Proteína Morfogenética Óssea 4/genética , Sistema Digestório/embriologia , Sistema Digestório/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Silenciamento de Genes , Glicoproteínas/genética , Glicoproteínas/metabolismo , Pulmão/embriologia , Pulmão/metabolismo , Modelos Biológicos , Oligodesoxirribonucleotídeos Antissenso/genética , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/genética , Retinal Desidrogenase , Transdução de Sinais , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , Xenopus/genética , Proteínas de Xenopus/antagonistas & inibidores , Proteínas de Xenopus/genética , Xenopus laevis/genética , Dedos de Zinco/genética , beta Catenina/genética , beta Catenina/metabolismo
18.
Dev Biol ; 378(1): 1-12, 2013 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-23562607

RESUMO

Wnt signaling has multiple dynamic roles during development of the gastrointestinal and respiratory systems. Differential Wnt signaling is thought to be a critical step in Xenopus endoderm patterning such that during late gastrula and early somite stages of embryogenesis, Wnt activity must be suppressed in the anterior to allow the specification of foregut progenitors. However, the foregut endoderm also expresses the Wnt-receptor Frizzled 7 (Fzd7) as well as several Wnt ligands suggesting that the current model may be too simple. In this study, we show that Fzd7 is required to transduce a low level of Wnt signaling that is essential to maintain foregut progenitors. Foregut-specific Fzd7-depletion from the Xenopus foregut resulted in liver and pancreas agenesis. Fzd7-depleted embryos failed to maintain the foregut progenitor marker hhex and exhibited decreased proliferation; in addition the foregut cells were enlarged with a randomized orientation. We show that in the foregut Fzd7 signals via both the Wnt/ß-catenin and Wnt/JNK pathways and that different thresholds of Wnt-Fzd7 activity coordinate progenitor cell fate, proliferation and morphogenesis.


Assuntos
Endoderma/citologia , Regulação da Expressão Gênica no Desenvolvimento , Receptores Acoplados a Proteínas G/metabolismo , Células-Tronco/citologia , Via de Sinalização Wnt , Proteínas de Xenopus/metabolismo , Animais , Padronização Corporal , Linhagem da Célula , Proliferação de Células , Proteínas de Homeodomínio/metabolismo , Intestinos/embriologia , MAP Quinase Quinase 4/metabolismo , Morfogênese/genética , Fatores de Transcrição/metabolismo , Proteínas Wnt/metabolismo , Xenopus laevis , beta Catenina/metabolismo
19.
J Cell Biochem ; 115(8): 1343-50, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24644080

RESUMO

The epithelial lining of the respiratory system originates from a small group of progenitor cells in the ventral foregut endoderm of the early embryo. Research in the last decade has revealed a number of paracrine signaling pathways that are critical for the development of these respiratory progenitors. In the post-genomic era the challenge now is to figure out at the genome wide level how these different signaling pathways and their downstream transcription factors interact in a complex "gene regulatory network" (GRN) to orchestrate early lung development. In this prospective, we review our growing understanding of the GRN governing lung specification. We discuss key gaps in our knowledge and describe emerging opportunities that will soon provide an unprecedented understanding of lung development and accelerate our ability to apply this knowledge to regenerative medicine.


Assuntos
Desenvolvimento Embrionário/genética , Redes Reguladoras de Genes/genética , Pulmão/crescimento & desenvolvimento , Organogênese/genética , Animais , Linhagem da Célula/genética , Embrião de Mamíferos , Embrião não Mamífero , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Pulmão/citologia , Camundongos , Proteínas Nucleares/genética , Fator Nuclear 1 de Tireoide , Fatores de Transcrição/genética , Proteínas de Xenopus , Xenopus laevis/genética , Xenopus laevis/crescimento & desenvolvimento
20.
Mayo Clin Proc ; 99(6): 955-970, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38661599

RESUMO

The number of individuals referred for coronary artery bypass grafting (CABG) with preoperative atrial fibrillation (AF) is reported to be 8% to 20%. Atrial fibrillation is a known marker of high-risk patients as it was repeatedly found to negatively influence survival. Therefore, when performing surgical revascularization, consideration should be given to the concomitant treatment of the arrhythmia, the clinical consequences of the arrhythmia itself, and the selection of adequate surgical techniques. This state-of-the-art review aimed to provide a comprehensive analysis of the current understanding of, advancements in, and optimal strategies for CABG in patients with underlying AF. The following topics are considered: stroke prevention, prophylaxis and occurrence of postoperative AF, the role of surgical ablation and left atrial appendage occlusion, and an on-pump vs off-pump strategy. Multiple acute complications can occur in patients with preexisting AF undergoing CABG, each of which can have a significant effect on patient outcomes. Long-term results in these patients and the future perspectives of this scientific area were also addressed. Preoperative arrhythmia should always be considered for surgical ablation because such an approach improves prognosis without increasing perioperative risk. While planning a revascularization strategy, it should be noted that although off-pump coronary artery bypass provides better short-term outcomes, conventional on-pump approach may be beneficial at long-term follow-up. By collecting the current evidence, addressing knowledge gaps, and offering practical recommendations, this state-of-the-art review serves as a valuable resource for clinicians involved in the management of patients with AF undergoing CABG, ultimately contributing to improved outcomes and enhanced patient care.


Assuntos
Fibrilação Atrial , Ponte de Artéria Coronária , Humanos , Fibrilação Atrial/cirurgia , Fibrilação Atrial/complicações , Ponte de Artéria Coronária/métodos , Ponte de Artéria Coronária/efeitos adversos , Doença da Artéria Coronariana/cirurgia , Doença da Artéria Coronariana/complicações , Complicações Pós-Operatórias/prevenção & controle , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Ponte de Artéria Coronária sem Circulação Extracorpórea/métodos , Acidente Vascular Cerebral/prevenção & controle , Acidente Vascular Cerebral/etiologia
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