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1.
Cell ; 176(1-2): 85-97.e14, 2019 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-30580965

RESUMEN

Animals must respond to the ingestion of food by generating adaptive behaviors, but the role of gut-brain signaling in behavioral regulation is poorly understood. Here, we identify conserved ion channels in an enteric serotonergic neuron that mediate its responses to food ingestion and decipher how these responses drive changes in foraging behavior. We show that the C. elegans serotonergic neuron NSM acts as an enteric sensory neuron that acutely detects food ingestion. We identify the novel and conserved acid-sensing ion channels (ASICs) DEL-7 and DEL-3 as NSM-enriched channels required for feeding-dependent NSM activity, which in turn drives slow locomotion while animals feed. Point mutations that alter the DEL-7 channel change NSM dynamics and associated behavioral dynamics of the organism. This study provides causal links between food ingestion, molecular and physiological properties of an enteric serotonergic neuron, and adaptive feeding behaviors, yielding a new view of how enteric neurons control behavior.


Asunto(s)
Canales Iónicos Sensibles al Ácido/metabolismo , Sistema Nervioso Entérico/metabolismo , Conducta Alimentaria/fisiología , Canales Iónicos Sensibles al Ácido/fisiología , Animales , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/fisiología , Proteínas de Caenorhabditis elegans/metabolismo , Sistema Nervioso Entérico/fisiología , Alimentos , Canales Iónicos/metabolismo , Canales Iónicos/fisiología , Locomoción , Neuronas/metabolismo , Células Receptoras Sensoriales/metabolismo , Neuronas Serotoninérgicas/metabolismo , Neuronas Serotoninérgicas/fisiología , Serotonina , Transducción de Señal
2.
Nature ; 607(7917): 163-168, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35768509

RESUMEN

Pancreatic ductal adenocarcinoma (PDAC) shows pronounced epithelial and mesenchymal cancer cell populations1-4. Cellular heterogeneity in PDAC is an important feature in disease subtype specification3-5, but how distinct PDAC subpopulations interact, and the molecular mechanisms that underlie PDAC cell fate decisions, are incompletely understood. Here we identify the BMP inhibitor GREM16,7 as a key regulator of cellular heterogeneity in pancreatic cancer in human and mouse. Grem1 inactivation in established PDAC in mice resulted in a direct conversion of epithelial into mesenchymal PDAC cells within days, suggesting that persistent GREM1 activity is required to maintain the epithelial PDAC subpopulations. By contrast, Grem1 overexpression caused an almost complete 'epithelialization' of highly mesenchymal PDAC, indicating that high GREM1 activity is sufficient to revert the mesenchymal fate of PDAC cells. Mechanistically, Grem1 was highly expressed in mesenchymal PDAC cells and inhibited the expression of the epithelial-mesenchymal transition transcription factors Snai1 (also known as Snail) and Snai2 (also known as Slug) in the epithelial cell compartment, therefore restricting epithelial-mesenchymal plasticity. Thus, constant suppression of BMP activity is essential to maintain epithelial PDAC cells, indicating that the maintenance of the cellular heterogeneity of pancreatic cancer requires continuous paracrine signalling elicited by a single soluble factor.


Asunto(s)
Transición Epitelial-Mesenquimal , Péptidos y Proteínas de Señalización Intercelular , Neoplasias Pancreáticas , Animales , Carcinoma Ductal Pancreático/patología , Línea Celular Tumoral , Células Epiteliales/patología , Transición Epitelial-Mesenquimal/genética , Humanos , Péptidos y Proteínas de Señalización Intercelular/deficiencia , Péptidos y Proteínas de Señalización Intercelular/genética , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Mesodermo/patología , Ratones , Neoplasias Pancreáticas/patología , Factores de Transcripción de la Familia Snail
3.
PLoS Genet ; 19(3): e1010650, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36972301

RESUMEN

Habituation is a foundational learning process critical for animals to adapt their behavior to changes in their sensory environment. Although habituation is considered a simple form of learning, the identification of a multitude of molecular pathways including several neurotransmitter systems that regulate this process suggests an unexpected level of complexity. How the vertebrate brain integrates these various pathways to accomplish habituation learning, whether they act independently or intersect with one another, and whether they act via divergent or overlapping neural circuits has remained unclear. To address these questions, we combined pharmacogenetic pathway analysis with unbiased whole-brain activity mapping using the larval zebrafish. Based on our findings, we propose five distinct molecular modules for the regulation of habituation learning and identify a set of molecularly defined brain regions associated with four of the five modules. Moreover, we find that in module 1 the palmitoyltransferase Hip14 cooperates with dopamine and NMDA signaling to drive habituation, while in module 3 the adaptor protein complex subunit Ap2s1 drives habituation by antagonizing dopamine signaling, revealing two distinct and opposing roles for dopaminergic neuromodulation in the regulation of behavioral plasticity. Combined, our results define a core set of distinct modules that we propose act in concert to regulate habituation-associated plasticity, and provide compelling evidence that even seemingly simple learning behaviors in a compact vertebrate brain are regulated by a complex and overlapping set of molecular mechanisms.


Asunto(s)
Habituación Psicofisiológica , Pez Cebra , Animales , Pez Cebra/genética , Habituación Psicofisiológica/fisiología , Dopamina , Aprendizaje/fisiología , Encéfalo , Plasticidad Neuronal/genética
4.
Development ; 149(9)2022 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-35552393

RESUMEN

Nervous system assembly relies on a diversity of cellular processes ranging from dramatic tissue reorganization to local, subcellular changes all driven by precise molecular programs. Combined, these processes culminate in an animal's ability to plan and execute behaviors. Animal behavior can, therefore, serve as a functional readout of nervous system development. Benefitting from an expansive and growing set of molecular and imaging tools paired with an ever-growing number of assays of diverse behaviors, the zebrafish system has emerged as an outstanding platform at the intersection of nervous system assembly, plasticity and behavior. Here, we summarize recent advancements in the field, including how developing neural circuits are refined to shape complex behaviors and plasticity.


Asunto(s)
Sistema Nervioso , Pez Cebra , Animales , Conducta Animal/fisiología , Plasticidad Neuronal/fisiología
5.
Am J Pathol ; 2024 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-39222907

RESUMEN

Delayed diagnosis and treatment resistance make pancreatic ductal adenocarcinoma (PDAC) mortality rates high. Identifying molecular subtypes can improve treatment, but current methods are costly and time-consuming. In this study, deep learning models were used to identify histologic features that classify PDAC molecular subtypes based on routine hematoxylin-eosin-stained histopathologic slides. A total of 97 histopathology slides associated with resectable PDAC from The Cancer Genome Atlas project were used to train a deep learning model and tested the performance on 44 needle biopsy material (110 slides) from a local annotated patient cohort. The model achieved balanced accuracy of 96.19% and 83.03% in identifying the classical and basal subtypes of PDAC in The Cancer Genome Atlas and the local cohort, respectively. This study provides a promising method to cost-effectively and rapidly classifying PDAC molecular subtypes based on routine hematoxylin-eosin-stained slides, potentially leading to more effective clinical management of this disease.

6.
PLoS Genet ; 17(6): e1008943, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-34061829

RESUMEN

The acoustic startle response is an evolutionarily conserved avoidance behavior. Disruptions in startle behavior, particularly startle magnitude, are a hallmark of several human neurological disorders. While the neural circuitry underlying startle behavior has been studied extensively, the repertoire of genes and genetic pathways that regulate this locomotor behavior has not been explored using an unbiased genetic approach. To identify such genes, we took advantage of the stereotypic startle behavior in zebrafish larvae and performed a forward genetic screen coupled with whole genome analysis. We uncovered mutations in eight genes critical for startle behavior, including two genes encoding proteins associated with human neurological disorders, Dolichol kinase (Dolk), a broadly expressed regulator of the glycoprotein biosynthesis pathway, and the potassium Shaker-like channel subunit Kv1.1. We demonstrate that Kv1.1 and Dolk play critical roles in the spinal cord to regulate movement magnitude during the startle response and spontaneous swim movements. Moreover, we show that Kv1.1 protein is mislocalized in dolk mutants, suggesting they act in a common genetic pathway. Combined, our results identify a diverse set of eight genes, all associated with human disorders, that regulate zebrafish startle behavior and reveal a previously unappreciated role for Dolk and Kv1.1 in regulating movement magnitude via a common genetic pathway.


Asunto(s)
Pruebas Genéticas/métodos , Canal de Potasio Kv.1.1/genética , Fosfotransferasas (Aceptor de Grupo Alcohol)/fisiología , Reflejo de Sobresalto/genética , Proteínas de Pez Cebra/genética , Animales , Humanos , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Pez Cebra
7.
J Exp Bot ; 73(13): 4496-4513, 2022 07 16.
Artículo en Inglés | MEDLINE | ID: mdl-35536989

RESUMEN

Plant health depends not only on the condition of the plant itself but also on its diverse community of microbes, or microbiota. Just like the better-studied angiosperms, bryophytes (mosses, liverworts, and hornworts) harbor diverse communities of bacteria, archaea, fungi, and other microbial eukaryotes. Bryophytes are increasingly recognized as important model systems for understanding plant evolution, development, physiology, and symbiotic interactions. Much of the work on bryophyte microbiota in the past focused on specific symbiont types for each bryophyte group, but more recent studies are taking a broader view acknowledging the coexistence of diverse microbial communities in bryophytes. Therefore, this review integrates studies of bryophyte microbes from both perspectives to provide a holistic view of the existing research for each bryophyte group and on key themes. The systematic search also reveals the taxonomic and geographic biases in this field, including a severe under-representation of the tropics, very few studies on viruses or eukaryotic microbes beyond fungi, and a focus on mycorrhizal fungi studies in liverworts. Such gaps may have led to errors in conclusions about evolutionary patterns in symbiosis. This analysis points to a wealth of future research directions that promise to reveal how the distinct life cycles and physiology of bryophytes interact with their microbiota.


Asunto(s)
Briófitas , Microbiota , Hongos , Plantas , Simbiosis
8.
Am J Bot ; 109(6): 939-951, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35678538

RESUMEN

PREMISE: Chaetopeltidales is a poorly characterized order in the Chlorophyceae, with only two plastid and no mitochondrial genomes published. Here we describe a new taxon in Chaetopeltidales, Gormaniella terricola gen. et sp. nov. and characterize both of its organellar genomes. METHODS: Gormaniella terricola was inadvertently isolated from a surface-sterilized hornwort thallus. Light microscopy was used to characterize its vegetative morphology. Organellar genomes were assembled, annotated, and analyzed using a variety of software packages. RESULTS: The mitochondrial genome (66,927 bp) represents the first complete mitochondrial genome published for Chaetopeltidales. The chloroplast genome, measuring 428,981 bp, is one of the largest plastid genomes published to date and shares this large size and an incredible number of short, dispersed repeats with the other sequenced chloroplast genomes in Chaetopeltidales. Despite these shared features, the chloroplast genomes of Chaetopeltidales appear to be highly rearranged when compared to one another, with numerous inversions, translocations, and duplications, suggesting a particularly dynamic chloroplast genome. Both the chloroplast and mitochondrial genomes of G. terricola contain a number of mobile group I and group II introns, which appear to have invaded separately. Three of the introns within the mitochondrial genome encode homing endonucleases that are phylogenetically nested within those found in fungi, rather than algae, suggesting a possible case of horizontal gene transfer. CONCLUSIONS: These results help to shed light on a poorly understood group of algae and their unusual organellar genomes, raising additional questions about the unique patterns of genome evolution within Chaetopeltidales.


Asunto(s)
Chlorophyceae , Genoma del Cloroplasto , Genoma Mitocondrial , Genoma de Plastidios , Cloroplastos , Evolución Molecular , Genoma del Cloroplasto/genética , Genoma Mitocondrial/genética , Intrones , Filogenia
9.
Am J Bot ; 108(9): 1731-1744, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34533221

RESUMEN

PREMISE: Nitrogen-fixing endosymbioses with cyanobacteria have evolved independently in five very different plant lineages. Expanding knowledge of these symbioses promises to improve the understanding of symbiosis evolution and broaden the toolkit for agricultural engineering to reduce artificial fertilizer use. Here we focused on hornworts, a bryophyte lineage in which all members host cyanobacteria, and investigated factors shaping the diversity of their cyanobiont communities. METHODS: We sampled hornworts and adjacent soils in upstate New York throughout the hornwort growing season. We included all three sympatric hornwort species in the area, allowing us to directly compare partner selectivity. To profile cyanobacteria communities, we established a metabarcoding protocol targeting rbcL-X with PacBio long reads. RESULTS: The hornwort cyanobionts detected were phylogenetically diverse, including clades that do not contain other known plant symbionts. We found significant overlap between hornwort cyanobionts and soil cyanobacteria, a pattern not previously reported in other plant-cyanobacteria symbioses. Cyanobiont communities differed between host plants only centimeters apart, but we did not detect an effect of sampling time or host species on the cyanobacterial community structure. CONCLUSIONS: This study expands the phylogenetic diversity of known symbiotic cyanobacteria. Our analyses suggest that hornwort cyanobionts have a tight connection to the soil background, and we found no evidence that time within growing season, host species, or distance at the scale of meters strongly govern cyanobacteria community assembly. This study provides a critical foundation for further study of the ecology, evolution, and interaction dynamics of plant-cyanobacteria symbiosis.


Asunto(s)
Anthocerotophyta , Briófitas , Cianobacterias , Cianobacterias/genética , Filogenia , Simbiosis
10.
J Clin Psychol ; 77(12): 2929-2942, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34825357

RESUMEN

OBJECTIVES: Discrepancies persist regarding the extent to which different pain measures provide similar information and relate to capability for suicide and self-injurious behaviors. This study examined pain threshold, tolerance, and persistence across four modalities (cold, heat, pressure, shock) and assessed associations with self-reported capability for suicide, non-suicidal self-injury (NSSI), and suicide attempts. METHODS: A sample of 211 students who reported lifetime suicidal ideation completed four behavioral pain tasks and self-reported on capability for suicide, NSSI, and self-injurious behaviors. RESULTS: All pain thresholds, tolerances, and persistences were positively correlated across the four tasks. Pain facets were related to self-reported capability for suicide with small effect sizes but generally did not differ across suicide attempt or NSSI histories. CONCLUSIONS: Pain thresholds, tolerances, and persistences demonstrated convergent validity across the four modalities, suggesting that these tasks provide similar information. Although the relation between pain and self-injurious behaviors remains unclear, these tasks can generally be used interchangeably.


Asunto(s)
Umbral del Dolor , Conducta Autodestructiva , Humanos , Dolor/epidemiología , Factores de Riesgo , Autoinforme , Conducta Autodestructiva/epidemiología , Ideación Suicida , Intento de Suicidio
11.
Genes Dev ; 26(19): 2206-21, 2012 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-23028145

RESUMEN

The chemotrophic factor Netrin can simultaneously instruct different neurodevelopmental programs in individual neurons in vivo. How neurons correctly interpret the Netrin signal and undergo the appropriate neurodevelopmental response is not understood. Here we identify MIG-10 isoforms as critical determinants of individual cellular responses to Netrin. We determined that distinct MIG-10 isoforms, varying only in their N-terminal motifs, can localize to specific subcellular domains and are differentially required for discrete neurodevelopmental processes in vivo. We identified MIG-10B as an isoform uniquely capable of localizing to presynaptic regions and instructing synaptic vesicle clustering in response to Netrin. MIG-10B interacts with Abl-interacting protein-1 (ABI-1)/Abi1, a component of the WAVE complex, to organize the actin cytoskeleton at presynaptic sites and instruct vesicle clustering through SNN-1/Synapsin. We identified a motif in the MIG-10B N-terminal domain that is required for its function and localization to presynaptic sites. With this motif, we engineered a dominant-negative MIG-10B construct that disrupts vesicle clustering and animal thermotaxis behavior when expressed in a single neuron in vivo. Our findings indicate that the unique N-terminal domains confer distinct MIG-10 isoforms with unique capabilities to localize to distinct subcellular compartments, organize the actin cytoskeleton at these sites, and instruct distinct Netrin-dependent neurodevelopmental programs.


Asunto(s)
Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/embriología , Proteínas del Citoesqueleto/metabolismo , Proteínas del Tejido Nervioso/genética , Vesículas Sinápticas/metabolismo , Citoesqueleto de Actina/metabolismo , Animales , Conducta Animal/fisiología , Caenorhabditis elegans/metabolismo , Movimiento Celular , Proteínas del Citoesqueleto/genética , Perfilación de la Expresión Génica , Interneuronas/citología , Neuronas Motoras/citología , Proteínas del Tejido Nervioso/metabolismo , Netrinas , Isoformas de Proteínas , Transporte de Proteínas/genética , Vesículas Sinápticas/genética
12.
New Phytol ; 218(3): 1217-1232, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29411387

RESUMEN

Fungal symbioses are ubiquitous in plants, but their effects have mostly been studied in seed plants. This study aimed to assess the diversity of fungal endophyte effects in a bryophyte and identify factors contributing to the variability of outcomes in these interactions. Fungal endophyte cultures and axenic liverwort clones were isolated from wild populations of the liverwort, Marchantia polymorpha. These collections were combined in a gnotobiotic system to test the effects of fungal isolates on the growth rates of hosts under laboratory conditions. Under the experimental conditions, fungi isolated from M. polymorpha ranged from aggressively pathogenic to strongly growth-promoting, but the majority of isolates caused no detectable change in host growth. Growth promotion by selected fungi depended on nutrient concentrations and was inhibited by coinoculation with multiple fungi. The M. polymorpha endophyte system expands the resources for this model liverwort. The experiments presented here demonstrate a wealth of diversity in fungal interactions even in a host reported to lack standard mycorrhizal symbiosis. In addition, they show that some known pathogens of vascular plants live in M. polymorpha and can confer benefits to this nonvascular host. This highlights the importance of studying endophyte effects across the plant tree of life.


Asunto(s)
Endófitos/fisiología , Hongos/fisiología , Marchantia/microbiología , Marchantia/crecimiento & desarrollo , Filogenia , Xylariales/fisiología
13.
Circ Res ; 118(3): 410-9, 2016 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-26666640

RESUMEN

RATIONALE: The low-density lipoprotein (LDL) receptor (LDLR) is a central determinant of circulating LDL-cholesterol and as such subject to tight regulation. Recent studies and genetic evidence implicate the inducible degrader of the LDLR (IDOL) as a regulator of LDLR abundance and of circulating levels of LDL-cholesterol in humans. Acting as an E3-ubiquitin ligase, IDOL promotes ubiquitylation and subsequent lysosomal degradation of the LDLR. Consequently, inhibition of IDOL-mediated degradation of the LDLR represents a potential strategy to increase hepatic LDL-cholesterol clearance. OBJECTIVE: To establish whether deubiquitylases counteract IDOL-mediated ubiquitylation and degradation of the LDLR. METHODS AND RESULTS: Using a genetic screening approach, we identify the ubiquitin-specific protease 2 (USP2) as a post-transcriptional regulator of IDOL-mediated LDLR degradation. We demonstrate that both USP2 isoforms, USP2-69 and USP2-45, interact with IDOL and promote its deubiquitylation. IDOL deubiquitylation requires USP2 enzymatic activity and leads to a marked stabilization of IDOL protein. Paradoxically, this also markedly attenuates IDOL-mediated degradation of the LDLR and the ability of IDOL to limit LDL uptake into cells. Conversely, loss of USP2 reduces LDLR protein in an IDOL-dependent manner and limits LDL uptake. We identify a tri-partite complex encompassing IDOL, USP2, and LDLR and demonstrate that in this context USP2 promotes deubiquitylation of the LDLR and prevents its degradation. CONCLUSIONS: Our findings identify USP2 as a novel regulator of lipoprotein clearance owing to its ability to control ubiquitylation-dependent degradation of the LDLR by IDOL.


Asunto(s)
LDL-Colesterol/metabolismo , Endopeptidasas/metabolismo , Receptores de LDL/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Animales , Endopeptidasas/genética , Estabilidad de Enzimas , Células HEK293 , Células HeLa , Células Hep G2 , Humanos , Ratones Noqueados , Complejos Multienzimáticos , Unión Proteica , Proteolisis , Interferencia de ARN , Receptores de LDL/genética , Transfección , Ubiquitina Tiolesterasa , Ubiquitina-Proteína Ligasas/deficiencia , Ubiquitina-Proteína Ligasas/genética , Ubiquitinación
14.
Circ Res ; 118(2): 222-9, 2016 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-26582775

RESUMEN

RATIONALE: The (pro)renin receptor ([P]RR) interacts with (pro)renin at concentrations that are >1000× higher than observed under (patho)physiological conditions. Recent studies have identified renin-angiotensin system-independent functions for (P)RR related to its association with the vacuolar H(+)-ATPase. OBJECTIVE: To uncover renin-angiotensin system-independent functions of the (P)RR. METHODS AND RESULTS: We used a proteomics-based approach to purify and identify (P)RR-interacting proteins. This resulted in identification of sortilin-1 (SORT1) as a high-confidence (P)RR-interacting protein, a finding which was confirmed by coimmunoprecipitation of endogenous (P)RR and SORT1. Functionally, silencing (P)RR expression in hepatocytes decreased SORT1 and low-density lipoprotein (LDL) receptor protein abundance and, as a consequence, resulted in severely attenuated cellular LDL uptake. In contrast to LDL, endocytosis of epidermal growth factor or transferrin remained unaffected by silencing of the (P)RR. Importantly, reduction of LDL receptor and SORT1 protein abundance occurred in the absence of changes in their corresponding transcript level. Consistent with a post-transcriptional event, degradation of the LDL receptor induced by (P)RR silencing could be reversed by lysosomotropic agents, such as bafilomycin A1. CONCLUSIONS: Our study identifies a renin-angiotensin system-independent function for the (P)RR in the regulation of LDL metabolism by controlling the levels of SORT1 and LDL receptor.


Asunto(s)
Endocitosis , Hepatocitos/metabolismo , Lipoproteínas LDL/metabolismo , Proteómica , Receptores de Superficie Celular/metabolismo , ATPasas de Translocación de Protón Vacuolares/metabolismo , Proteínas Adaptadoras del Transporte Vesicular/genética , Proteínas Adaptadoras del Transporte Vesicular/metabolismo , Animales , Células CHO , Inmunoprecipitación de Cromatina , Cricetulus , Células HEK293 , Células Hep G2 , Humanos , Procesamiento Proteico-Postraduccional , Proteolisis , Proteómica/métodos , Interferencia de ARN , Receptores de Superficie Celular/genética , Receptores de LDL/genética , Receptores de LDL/metabolismo , Transfección , ATPasas de Translocación de Protón Vacuolares/genética
15.
Arterioscler Thromb Vasc Biol ; 37(3): 423-432, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28082258

RESUMEN

OBJECTIVE: The sterol-responsive nuclear receptors, liver X receptors α (LXRα, NR1H3) and ß (LXRß, NR1H2), are key determinants of cellular cholesterol homeostasis. LXRs are activated under conditions of high cellular sterol load and induce expression of the cholesterol efflux transporters ABCA1 and ABCG1 to promote efflux of excess cellular cholesterol. However, the full set of genes that contribute to LXR-stimulated cholesterol efflux is unknown, and their identification is the objective of this study. APPROACH AND RESULTS: We systematically compared the global transcriptional response of macrophages to distinct classes of LXR ligands. This allowed us to identify both common and ligand-specific transcriptional responses in macrophages. Among these, we identified endonuclease-exonuclease-phosphatase family domain containing 1 (EEPD1/KIAA1706) as a direct transcriptional target of LXRs in human and murine macrophages. EEPD1 specifically localizes to the plasma membrane owing to the presence of a myristoylation site in its N terminus. Accordingly, the first 10 amino acids of EEPD1 are sufficient to confer plasma membrane localization in the context of a chimeric protein with GFP. Functionally, we report that silencing expression of EEPD1 blunts maximal LXR-stimulated Apo AI-dependent efflux and demonstrate that this is the result of reduced abundance of ABCA1 protein in human and murine macrophages. CONCLUSIONS: In this study, we identify EEPD1 as a novel LXR-regulated gene in macrophages and propose that it promotes cellular cholesterol efflux by controlling cellular levels and activity of ABCA1.


Asunto(s)
Transportador 1 de Casete de Unión a ATP/metabolismo , Membrana Celular/enzimología , Colesterol/metabolismo , Endodesoxirribonucleasas/metabolismo , Receptores X del Hígado/metabolismo , Macrófagos/enzimología , Transportador 1 de Casete de Unión a ATP/genética , Animales , Apolipoproteína A-I/metabolismo , Transporte Biológico , Células COS , Membrana Celular/efectos de los fármacos , Chlorocebus aethiops , Endodesoxirribonucleasas/genética , Perfilación de la Expresión Génica/métodos , Regulación Enzimológica de la Expresión Génica , Células HeLa , Células Hep G2 , Humanos , Ligandos , Receptores X del Hígado/agonistas , Receptores X del Hígado/deficiencia , Receptores X del Hígado/genética , Macrófagos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Células RAW 264.7 , Interferencia de ARN , Transcriptoma , Transfección
16.
Curr Rheumatol Rep ; 20(10): 60, 2018 08 14.
Artículo en Inglés | MEDLINE | ID: mdl-30109511

RESUMEN

PURPOSE OF REVIEW: Lupus nephritis is a frequent complication of systemic lupus erythematosus and is more common and severe in children. This is a disease of the immune system characterized by T cell, B cell, and complement activation, as well as immune complex formation and deposition. The introduction of steroids and later cyclophosphamide transformed lupus nephritis from a fatal to a treatable condition. However, the standard therapies currently used for treatment carry significant toxicity and chronic kidney disease still remains a far too frequent outcome. To address these issues, we will review current and emerging induction therapies in LN. RECENT FINDINGS: Several clinical trials have been undertaken to test more effective and safer drugs, often targeting mechanistic disease pathways. At present, it is difficult to identify an induction regimen that is more effective and less toxic than the standard of care; however, we believe continuing efforts in drug development will bring breakthrough agents to clinics.


Asunto(s)
Inmunosupresores/uso terapéutico , Nefritis Lúpica/tratamiento farmacológico , Depleción Linfocítica/métodos , Inducción de Remisión/métodos , Linfocitos B , Ciclofosfamida/uso terapéutico , Glucocorticoides/uso terapéutico , Humanos
17.
J Biol Chem ; 291(9): 4813-25, 2016 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-26719329

RESUMEN

Cholesterol metabolism is subject to complex transcriptional and nontranscriptional regulation. Herein, the role of ubiquitylation is emerging as an important post-translational modification that regulates cholesterol synthesis and uptake. Similar to other post-translational modifications, ubiquitylation is reversible in a process dependent on activity of deubiquitylating enzymes (DUBs). Yet whether these play a role in cholesterol metabolism is largely unknown. As a first step to test this possibility, we used pharmacological inhibition of cellular DUB activity. Short term (2 h) inhibition of DUBs resulted in accumulation of high molecular weight ubiquitylated proteins. This was accompanied by a dramatic decrease in abundance of the LDLR and attenuated LDL uptake into hepatic cells. Importantly, this occurred in the absence of changes in the mRNA levels of the LDLR or other SREBP2-regulated genes, in line with this phenotype being a post-transcriptional event. Mechanistically, we identify transcriptional induction of the E3 ubiquitin ligase IDOL in human and rodent cells as the underlying cause for ubiquitylation-dependent lysosomal degradation of the LDLR following DUB inhibition. In contrast to the established transcriptional regulation of IDOL by the sterol-responsive liver X receptor (LXR) transcription factors, induction of IDOL by DUB inhibition is LXR-independent and occurs in Lxrαß(-/-) MEFs. Consistent with the role of DUBs in transcriptional regulation, we identified a 70-bp region in the proximal promoter of IDOL, distinct from that containing the LXR-responsive element, which mediates the response to DUB inhibition. In conclusion, we identify a sterol-independent mechanism to regulate IDOL expression and IDOL-mediated lipoprotein receptor degradation.


Asunto(s)
Lipoproteínas LDL/metabolismo , Regiones Promotoras Genéticas , Receptores de LDL/metabolismo , Transcripción Genética , Ubiquitina-Proteína Ligasas/metabolismo , Proteasas Ubiquitina-Específicas/metabolismo , Absorción Fisiológica/efectos de los fármacos , Sustitución de Aminoácidos , Animales , Línea Celular , Células Cultivadas , Inhibidores Enzimáticos/farmacología , Genes Reporteros , Células Endoteliales de la Vena Umbilical Humana/citología , Humanos , Receptores X del Hígado , Lisosomas/efectos de los fármacos , Lisosomas/enzimología , Lisosomas/metabolismo , Ratones , Mutación , Receptores Nucleares Huérfanos/genética , Receptores Nucleares Huérfanos/metabolismo , Regiones Promotoras Genéticas/efectos de los fármacos , Proteolisis/efectos de los fármacos , Receptores de LDL/genética , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Transcripción Genética/efectos de los fármacos , Ubiquitina-Proteína Ligasas/química , Proteasas Ubiquitina-Específicas/antagonistas & inhibidores , Proteasas Ubiquitina-Específicas/genética , Ubiquitinación/efectos de los fármacos
18.
Development ; 141(2): 422-35, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24353061

RESUMEN

Transcription factors that drive neuron type-specific terminal differentiation programs in the developing nervous system are often expressed in several distinct neuronal cell types, but to what extent they have similar or distinct activities in individual neuronal cell types is generally not well explored. We investigate this problem using, as a starting point, the C. elegans LIM homeodomain transcription factor ttx-3, which acts as a terminal selector to drive the terminal differentiation program of the cholinergic AIY interneuron class. Using a panel of different terminal differentiation markers, including neurotransmitter synthesizing enzymes, neurotransmitter receptors and neuropeptides, we show that ttx-3 also controls the terminal differentiation program of two additional, distinct neuron types, namely the cholinergic AIA interneurons and the serotonergic NSM neurons. We show that the type of differentiation program that is controlled by ttx-3 in different neuron types is specified by a distinct set of collaborating transcription factors. One of the collaborating transcription factors is the POU homeobox gene unc-86, which collaborates with ttx-3 to determine the identity of the serotonergic NSM neurons. unc-86 in turn operates independently of ttx-3 in the anterior ganglion where it collaborates with the ARID-type transcription factor cfi-1 to determine the cholinergic identity of the IL2 sensory and URA motor neurons. In conclusion, transcription factors operate as terminal selectors in distinct combinations in different neuron types, defining neuron type-specific identity features.


Asunto(s)
Proteínas de Caenorhabditis elegans/genética , Proteínas de Homeodominio/genética , Neuronas/citología , Neuronas/metabolismo , Neuropéptidos/genética , Factores del Dominio POU/genética , Animales , Caenorhabditis elegans/genética , Caenorhabditis elegans/crecimiento & desarrollo , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Diferenciación Celular/genética , Neuronas Colinérgicas/citología , Neuronas Colinérgicas/metabolismo , Regulación del Desarrollo de la Expresión Génica , Genes de Helminto , Proteínas de Homeodominio/metabolismo , Interneuronas/citología , Interneuronas/metabolismo , Larva/citología , Larva/crecimiento & desarrollo , Larva/metabolismo , Neurogénesis/genética , Neuronas/clasificación , Neuropéptidos/metabolismo , Factores del Dominio POU/metabolismo , Neuronas Serotoninérgicas/citología , Neuronas Serotoninérgicas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
19.
Chembiochem ; 18(4): 402-412, 2017 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-28000364

RESUMEN

Galactosylceramidase (GALC) is the lysosomal ß-galactosidase responsible for the hydrolysis of galactosylceramide. Inherited deficiency in GALC causes Krabbe disease, a devastating neurological disorder characterized by accumulation of galactosylceramide and its deacylated counterpart, the toxic sphingoid base galactosylsphingosine (psychosine). We report the design and application of a fluorescently tagged activity-based probe (ABP) for the sensitive and specific labeling of active GALC molecules from various species. The probe consists of a ß-galactopyranose-configured cyclophellitol-epoxide core, conferring specificity for GALC, equipped with a BODIPY fluorophore at C6 that allows visualization of active enzyme in cells and tissues. Detection of residual GALC in patient fibroblasts holds great promise for laboratory diagnosis of Krabbe disease. We further describe a procedure for in situ imaging of active GALC in murine brain by intra-cerebroventricular infusion of the ABP. In conclusion, this GALC-specific ABP should find broad applications in diagnosis, drug development, and evaluation of therapy for Krabbe disease.


Asunto(s)
Galactosilceramidasa/genética , Galactosilceramidasa/metabolismo , Leucodistrofia de Células Globoides/enzimología , Sondas Moleculares , Enfermedades Carenciales/enzimología , Enfermedades Carenciales/genética , Galactosilceramidasa/antagonistas & inhibidores , Leucodistrofia de Células Globoides/diagnóstico , Leucodistrofia de Células Globoides/genética , Enfermedades por Almacenamiento Lisosomal/enzimología , Enfermedades por Almacenamiento Lisosomal/genética , Estructura Molecular , Mutación
20.
Acad Psychiatry ; 41(4): 471-476, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28265891

RESUMEN

OBJECTIVE: The study collected data on the attitudes of residents toward religion and spirituality in their practice after taking part in a 3-year curriculum on spirituality during their residency. METHODS: This is a descriptive, single-site study with psychiatry residents as subjects. A questionnaire was given to the residents at the end of their third year of residency (N = 12). RESULTS: The responses heavily endorsed the religiousness/spirituality curriculum to be helpful and meaningful. Residents consider addressing spiritual and religious needs of patients to be important (76.9%) and appropriate. For majority of the residents (69.2%), there is strong agreement in the management of addictions having spiritual dimensions. Residents also strongly agreed that treatment of suffering, depression, guilt, and complicated grief may require attention to spiritual concerns (92-100%). CONCLUSION: Regardless of cultural or religious background, the residents endorsed the curriculum as a worthwhile experience and increased their appreciation of the place of spirituality in the holistic care of patients with psychiatric conditions.


Asunto(s)
Actitud del Personal de Salud , Curriculum , Internado y Residencia/métodos , Psiquiatría/educación , Espiritualidad , Adulto , Femenino , Humanos , India , Masculino , Persona de Mediana Edad , Nigeria , Pakistán , Sierra Leona , España , Encuestas y Cuestionarios , Emiratos Árabes Unidos , Estados Unidos
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