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Over the last decade, automatic chemical design frameworks for discovering molecules with drug-like properties have significantly progressed. Among them, the variational autoencoder (VAE) is a cutting-edge approach that models the tractable latent space of the molecular space. In particular, the usage of a VAE along with a property estimator has attracted considerable interest because it enables gradient-based optimization of a given molecule. However, although successful results have been achieved experimentally, the theoretical background and prerequisites for the correct operation of this method have not yet been clarified. In view of the above, we theoretically analyze and rigorously reconstruct the entire framework. From the perspective of parameterized distribution and the information theory, we first describe how the previous model overcomes the limitations of the beta VAE in discovering molecules with the desired properties. Furthermore, we describe the prerequisites for training the above model. Next, from the log-likelihood perspective of each term, we reformulate the objectives for exploring latent space to generate drug-like molecules. The distributional constraints are defined in this study, which will break away from the invalid molecular search. We demonstrated that our model could discover a novel chemical compound for targeting BCL-2 family proteins in de novo approach. Through the theoretical analysis and practical implementation, the importance of the aforementioned prerequisites and constraints to operate the model was verified.
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Algoritmos , Diseño de Fármacos , Humanos , Proteínas Proto-Oncogénicas c-bcl-2/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/químicaRESUMEN
With over 16 million submitted genomic sequences, the SARS-CoV-2 (SC2) virus, the cause of the most recent worldwide COVID-19 pandemic, has become the most sequenced genome of all known viruses, revealing, for example, a vast number of expanding viral lineages. Since the pandemic phase appears to be over, we performed a retrospective re-examination of the demographic grouping pattern and their genomic characteristics during the entire pandemic period up to the peak of the last pandemic wave. For our study, we extracted from the NCBI only unique viral sequences and converted each sequence data to a relational vector, indicating the presence/absence of each variational event compared to a "reference" sequence. Our study revealed several genomic features that are unexpected or different from those of previous studies. For example, approximately 44,000 variants with unique sequences emerged during the pandemic period; they group into only four major viral-genomic groups and each has a set of mostly unique highly-conserved variant-genotypes (HCVGs); and a small set from the first ("ancestral") group was inherited by the three ("descendant") groups, suggesting that HCVGs in the next group may be predictable from the current group(s). Such a concept may be potentially important in designing "panvalent" vaccines against the current and future waves of viral infections.
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Vacunas contra la COVID-19 , COVID-19 , Genoma Viral , Pandemias , SARS-CoV-2 , SARS-CoV-2/genética , SARS-CoV-2/inmunología , Humanos , COVID-19/epidemiología , COVID-19/prevención & control , COVID-19/virología , Vacunas contra la COVID-19/inmunología , Pandemias/prevención & control , Estudios Retrospectivos , FilogeniaRESUMEN
Designing drugs capable of binding to the structure of target proteins for treating diseases is essential in drug development. Recent remarkable advancements in geometric deep learning have led to unprecedented progress in three-dimensional (3D) generation of ligands that can bind to the protein pocket. However, most existing methods primarily focus on modeling the geometric information of ligands in 3D space. Consequently, these methods fail to consider that the binding of proteins and ligands is a phenomenon driven by intrinsic physicochemical principles. Motivated by this understanding, we propose PIDiff, a model for generating molecules by accounting in the physicochemical principles of protein-ligand binding. Our model learns not only the structural information of proteins and ligands but also to minimize the binding free energy between them. To evaluate the proposed model, we introduce an experimental framework that surpasses traditional assessment methods by encompassing various essential aspects for the practical application of generative models to actual drug development. The results confirm that our model outperforms baseline models on the CrossDocked2020 benchmark dataset, demonstrating its superiority. Through diverse experiments, we have illustrated the promising potential of the proposed model in practical drug development.
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Proteínas , Proteínas/química , Ligandos , Modelos Moleculares , Humanos , Conformación ProteicaRESUMEN
All current categorizations of human population, such as ethnicity, ancestry and race, are based on various selections and combinations of complex and dynamic common characteristics, that are mostly societal and cultural in nature, perceived by the members within or from outside of the categorized group. During the last decade, a massive amount of a new type of characteristics, that are exclusively genomic in nature, became available that allows us to analyze the inherited whole-genome demographics of extant human, especially in the fields such as human genetics, health sciences and medical practices (e.g., 1,2,3), where such health-related characteristics can be related to whole-genome-based categorization. Here we show the feasibility of deriving such whole-genome-based categorization. We observe that, within the available genomic data at present, (a) the study populations form about 14 genomic groups, each consisting of multiple ethnic groups; and (b), at an individual level, approximately 99.8%, on average, of the whole autosomal-genome contents are identical between any two individuals regardless of their genomic or ethnic groups.
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Etnicidad , Genómica , Humanos , Etnicidad/genética , Genoma HumanoRESUMEN
The discovery of drugs to selectively remove disease-related cells is challenging in computer-aided drug design. Many studies have proposed multi-objective molecular generation methods and demonstrated their superiority using the public benchmark dataset for kinase inhibitor generation tasks. However, the dataset does not contain many molecules that violate Lipinski's rule of five. Thus, it remains unclear whether existing methods are effective in generating molecules violating the rule, such as navitoclax. To address this, we analysed the limitations of existing methods and propose a multi-objective molecular generation method with a novel parsing algorithm for molecular string representation and a modified reinforcement learning method for the efficient training of multi-objective molecular optimisation. The proposed model had success rates of 84% in GSK3b+JNK3 inhibitor generation and 99% in Bcl-2 family inhibitor generation tasks.
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Antineoplásicos , Diseño de Fármacos , Algoritmos , Inhibidores de Proteínas QuinasasRESUMEN
Honey bees play a significant role in ecology, producing biologically active substances used to promote human health. However, unlike humans, the molecular markers indicating honey bee health remain unknown. Unfortunately, numerous reports of honey bee collapse have been documented. To identify health markers, we analyzed ten defense system genes in Apis mellifera ligustica honey bees from winter (Owb) and spring (Fb for foragers and Nb for newly emerged) populations sampled in February and late April 2023, respectively. We focused on colonies free from SBV and DWV viruses. Molecular profiling revealed five molecular markers of honey bee health. Of these, two seasonal molecular markers-domeless and spz genes-were significantly downregulated in Owb compared to Nb and Fb honey bees. One task-related marker gene, apid-1, was identified as being downregulated in Owb and Nb compared to Fb honey bees. Two recommended general health markers, SOD and defensin-2, were upregulated in honey bees. These markers require further testing across various honey bee subspecies in different climatic regions. They can diagnose bee health without colony intervention, especially during low-temperature months like winter. Beekeepers can use this information to make timely adjustments to nutrients or heating to prevent seasonal losses.
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Frío , Ecología , Humanos , Abejas/genética , Animales , Estaciones del Año , Calefacción , NutrientesRESUMEN
In this paper, a reinforcement learning model is proposed that can maximize the predicted binding affinity between a generated molecule and target proteins. The model used to generate molecules in the proposed model was the Stacked Conditional Variation AutoEncoder (Stack-CVAE), which acts as an agent in reinforcement learning so that the resulting chemical formulas have the desired chemical properties and show high binding affinity with specific target proteins. We generated 1000 chemical formulas using the chemical properties of sorafenib and the three target kinases of sorafenib. Then, we confirmed that Stack-CVAE generates more of the valid and unique chemical compounds that have the desired chemical properties and predicted binding affinity better than other generative models. More detailed analysis for 100 of the top scoring molecules show that they are novel ones not found in existing chemical databases. Moreover, they reveal significantly higher predicted binding affinity score for Raf kinases than for other kinases. Furthermore, they are highly druggable and synthesizable.
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Senescent cells exhibit a reduced response to intrinsic and extrinsic stimuli. This diminished reaction may be explained by the disrupted transmission of nuclear signals. However, this hypothesis requires more evidence before it can be accepted as a mechanism of cellular senescence. A proteomic analysis of the cytoplasmic and nuclear fractions obtained from young and senescent cells revealed disruption of nucleocytoplasmic trafficking (NCT) as an essential feature of replicative senescence (RS) at the global level. Blocking NCT either chemically or genetically induced the acquisition of an RS-like senescence phenotype, named nuclear barrier-induced senescence (NBIS). A transcriptome analysis revealed that, among various types of cellular senescence, NBIS exhibited a gene expression pattern most similar to that of RS. Core proteomic and transcriptomic patterns common to both RS and NBIS included upregulation of the endocytosis-lysosome network and downregulation of NCT in senescent cells, patterns also observed in an aging yeast model. These results imply coordinated aging-dependent reduction in the transmission of extrinsic signals to the nucleus and in the nucleus-to-cytoplasm supply of proteins/RNAs. We further showed that the aging-associated decrease in Sp1 transcription factor expression was critical for the downregulation of NCT. Our results suggest that NBIS is a modality of cellular senescence that may represent the nature of physiological aging in eukaryotes.
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Senescencia Celular , Proteómica , Núcleo Celular/metabolismo , Senescencia Celular/genética , Regulación hacia AbajoRESUMEN
TRPM2 a cation channel is also known to work as an enzyme that hydrolyzes highly reactive, neurotoxic ADP-ribose (ADPR). Although ADPR is hydrolyzed by NUT9 pyrophosphatase in major organs, the enzyme is defective in the brain. The present study questions the role of TRPM2 in the catabolism of ADPR in the brain. Genetic ablation of Trpm2 results in the disruption of ADPR catabolism that leads to the accumulation of ADPR and reduction in AMP. Trpm2-/- mice elicit the reduction in autophagosome formation in the hippocampus. Trpm2-/- mice also show aggregations of proteins in the hippocampus, aberrant structural changes and neuronal connections in synapses, and neuronal degeneration. Trpm2-/- mice exhibit learning and memory impairment, enhanced neuronal intrinsic excitability, and imbalanced synaptic transmission. These results respond to long-unanswered questions regarding the potential role of the enzymatic function of TRPM2 in the brain, whose dysfunction evokes protein aggregation. In addition, the present finding answers to the conflicting reports such as neuroprotective or neurodegenerative phenotypes observed in Trpm2-/- mice.
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Adenosina Difosfato Ribosa/metabolismo , Autofagia , Encéfalo/metabolismo , Eliminación de Gen , Agregado de Proteínas , Canales Catiónicos TRPM/deficiencia , Animales , Cognición , Hipocampo/metabolismo , Hidrólisis , Memoria , Ratones Endogámicos C57BL , Ratones Noqueados , Degeneración Nerviosa/metabolismo , Degeneración Nerviosa/patología , Plasticidad Neuronal , Neuronas/metabolismo , Transmisión Sináptica , Canales Catiónicos TRPM/metabolismoRESUMEN
Prevention and early intervention are the most effective ways of avoiding or minimizing psychological, physical, and financial suffering from cancer. However, such proactive action requires the ability to predict the individual's susceptibility to cancer with a measure of probability. Of the triad of cancer-causing factors (inherited genomic susceptibility, environmental factors, and lifestyle factors), the inherited genomic component may be derivable from the recent public availability of a large body of whole-genome variation data. However, genome-wide association studies have so far showed limited success in predicting the inherited susceptibility to common cancers. We present here a multiple classification approach for predicting individuals' inherited genomic susceptibility to acquire the most likely phenotype among a panel of 20 major common cancer types plus 1 "healthy" type by application of a supervised machine-learning method under competing conditions among the cohorts of the 21 types. This approach suggests that, depending on the phenotypes of 5,919 individuals of "white" ethnic population in this study, (i) the portion of the cohort of a cancer type who acquired the observed type due to mostly inherited genomic susceptibility factors ranges from about 33 to 88% (or its corollary: the portion due to mostly environmental and lifestyle factors ranges from 12 to 67%), and (ii) on an individual level, the method also predicts individuals' inherited genomic susceptibility to acquire the other types ranked with associated probabilities. These probabilities may provide practical information for individuals, heath professionals, and health policymakers related to prevention and/or early intervention of cancer.
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Predisposición Genética a la Enfermedad , Aprendizaje Automático , Neoplasias/genética , Polimorfismo de Nucleótido Simple , Genoma Humano , Humanos , Estilo de Vida , ProbabilidadRESUMEN
The aim of the present study was to examine whether transient receptor potential melastatin 2 (TRPM2) plays a role in muscle fiber-type transition during exercise. Mice were trained at a speed of 12 m/min at a slope of 0° for 60 min for 5 consecutive days/wk for 4 wk. Exhaustion tests were performed on the treadmill (the speed was set at 6 m/min at a slope of 0° and increased at a rate of 1 m/min every 6 min). Isolated primary skeletal muscle cells from TRPM2-knockout (KO) mice showed lower amplitudes of electrical stimuli (ES)-induced Ca2+ signals when compared with wild-type (WT) mice due to a defect in Ca2+ influx. Moreover, TRPM2-KO mice had a higher proportion of fast-twitch skeletal muscle fibers and a lower proportion of slow-twitch muscle fibers before exercise than WT mice. After exercise, the expression of slow-twitch skeletal muscle fibers was increased only in WT mice but not in TRPM2-KO mice. ES-induced nuclear translocation of the Ca2+-dependent transcription factor NFATc1 was significantly lower in TRPM2-KO mice than in WT mice. TRPM2-KO mice also showed decreased mitochondrial Ca2+ and membrane potential. Lactate levels were higher in the skeletal muscle cells of TRPM2-KO mice before and after ES compared with WT mice. Collectively, these data indicate that TRPM2-mediated Ca2+ signaling plays a critical role in the regulation of fiber-type switching and mitochondrial function in skeletal muscle. NEW & NOTEWORTHY TRPM2 has been shown to play an important role in a variety of cellular functions. However, the role of TRPM2 in skeletal muscle remains poorly understood. Here, we provide evidence that TRPM2-mediated Ca2+ signaling is required for training-induced improvement in skeletal muscle mitochondrial function and fiber type transition.
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Señalización del Calcio , Mitocondrias Musculares/metabolismo , Músculo Esquelético/fisiología , Condicionamiento Físico Animal/fisiología , Canales Catiónicos TRPM/metabolismo , Animales , Tolerancia al Ejercicio , Masculino , Ratones Noqueados , Piruvato Deshidrogenasa (Lipoamida)/metabolismoRESUMEN
CD31 has been shown to play a role in endothelial cell migration and angiogenesis, which are critical to the formation and function of the endometrium and myometrium in uterine development during early pregnancy. However, the role of CD31 in uterine receptivity during blastocyst implantation is poorly understood. The pregnancy rate in CD31-/- female mice mated with CD31+/+ male mice was higher than that observed in CD31+/+ female mice mated with CD31+/+ male mice. During the receptive phase of implantation, uterine glands were more developed in CD31-/- mice than in CD31+/+ mice, and the uterine weights of CD31-/- mice were increased. Leukemia inhibitory factor (LIF) was highly expressed in the CD31-/- mice during implantation and the expression of LIF was up-regulated by estradiol-17ß (E2 ) + progesterone (P4 ) in ovariectomized CD31-/- mice, compared with CD31+/+ mice at 8 h after hormone treatment. E2 -induced protein synthesis was inhibited by P4 in the CD31+/+ uterus, but not in the uterus of CD31-/- mice. Also, STAT3, HAND2, LIF, and mTOR signals were enhanced in CD31-/- mice. Stromal DNA replication was highly activated in the uterus of CD31-/- mice, manifested by upregulated cyclin series signaling and PCNA expression after E2 + P4 treatment. Collectively, CD31 inhibits E2 -mediated epithelial proliferation via recruitment and phosphorylation of SHP-2 upon receiving P4 signal in early pregnancy.
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Molécula-1 de Adhesión Celular Endotelial de Plaqueta/fisiología , Progesterona/farmacología , Útero/metabolismo , Animales , Implantación del Embrión/efectos de los fármacos , Implantación del Embrión/genética , Endometrio/efectos de los fármacos , Endometrio/metabolismo , Estradiol/farmacología , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/genética , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/metabolismo , Embarazo , Transducción de Señal/efectos de los fármacos , Útero/efectos de los fármacosRESUMEN
To maintain genetic stability, the entire mammalian genome must replicate only once per cell cycle. This is largely achieved by strictly regulating the stepwise formation of the pre-replication complex (pre-RC), followed by the activation of individual origins of DNA replication by Cdc7/Dbf4 kinase. However, the mechanism how Cdc7 itself is regulated in the context of cell cycle progression is poorly understood. Here we report that Cdc7 is phosphorylated by a Cdk1-dependent manner during prometaphase on multiple sites, resulting in its dissociation from origins. In contrast, Dbf4 is not removed from origins in prometaphase, nor is it degraded as cells exit mitosis. Our data thus demonstrates that constitutive phosphorylation of Cdc7 at Cdk1 recognition sites, but not the regulation of Dbf4, prevents the initiation of DNA replication in normally cycling cells and under conditions that promote re-replication in G2/M. As cells exit mitosis, PP1α associates with and dephosphorylates Cdc7. Together, our data support a model where Cdc7 (de)phosphorylation is the molecular switch for the activation and inactivation of DNA replication in mitosis, directly connecting Cdc7 and PP1α/Cdk1 to the regulation of once-per-cell cycle DNA replication in mammalian cells.
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Proteínas de Ciclo Celular/genética , Quinasas Ciclina-Dependientes/genética , Replicación del ADN , Mitosis , Proteína Fosfatasa 1/genética , Proteínas Serina-Treonina Quinasas/genética , Proteína Quinasa CDC2 , Proteínas de Ciclo Celular/metabolismo , Quinasas Ciclina-Dependientes/metabolismo , Puntos de Control de la Fase G2 del Ciclo Celular , Genes Reporteros , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Células HEK293 , Células HeLa , Humanos , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Fosforilación , Proteína Fosfatasa 1/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteína Fluorescente RojaRESUMEN
BACKGROUND: Linker histone H1 is a core chromatin component that binds to nucleosome core particles and the linker DNA between nucleosomes. It has been implicated in chromatin compaction and gene regulation and is anticipated to play a role in higher-order genome structure. Here we have used a combination of genome-wide approaches including DNA methylation, histone modification and DNase I hypersensitivity profiling as well as Hi-C to investigate the impact of reduced cellular levels of histone H1 in embryonic stem cells on chromatin folding and function. RESULTS: We find that depletion of histone H1 changes the epigenetic signature of thousands of potential regulatory sites across the genome. Many of them show cooperative loss or gain of multiple chromatin marks. Epigenetic alterations cluster to gene-dense topologically associating domains (TADs) that already showed a high density of corresponding chromatin features. Genome organization at the three-dimensional level is largely intact, but we find changes in the structural segmentation of chromosomes specifically for the epigenetically most modified TADs. CONCLUSIONS: Our data show that cells require normal histone H1 levels to expose their proper regulatory landscape. Reducing the levels of histone H1 results in massive epigenetic changes and altered topological organization particularly at the most active chromosomal domains. Changes in TAD configuration coincide with epigenetic landscape changes but not with transcriptional output changes, supporting the emerging concept that transcriptional control and nuclear positioning of TADs are not causally related but independently controlled by the locally associated trans-acting factors.
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Ensamble y Desensamble de Cromatina , Epigénesis Genética , Histonas/metabolismo , Animales , Línea Celular , Cromatina/genética , Cromatina/metabolismo , Histonas/genética , RatonesRESUMEN
Human sperm have to undergo a maturational process called capacitation in the female reproductive tract. Capacitation confers upon the sperm an ability to gain hypermotility and undergo acrosome reaction. Previous studies have suggested that seminal plasma proteins induce the capacitation of sperm in the female reproductive tract for the successful fertilization of the oocyte. However, the function of seminal plasma proteins in capacitation remains largely unclear. To the end, we found that soluble CD38 (sCD38) in seminal plasma increases the capacitation of sperm via specific interactions between sCD38 and the CD31 on the sperm. Upon the association of sCD38 with CD31, tyrosine kinase Src phosphorylates CD31, a process blocked by Src inhibitors. Shc, SHP-2, Grb2, and SOS, as well as Src kinase were found to associate with the phosphorylated CD31. The sCD38-induced phosphorylation of CD31 initiates a cascade reaction through the phosphorylation of Erk1/2, which results in the acrosome reaction, and sperm hypermotility. These processes were prevented by Src, Ras and MEK inhibitors. Taken together, these data indicate that the sCD38 present in seminal plasma plays a critical role in the capacitation of sperm.
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ADP-Ribosil Ciclasa 1/metabolismo , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/metabolismo , Semen/metabolismo , Capacitación Espermática , Reacción Acrosómica , Humanos , Sistema de Señalización de MAP Quinasas , Masculino , Fosforilación , Fosfotirosina/metabolismo , Unión Proteica , Solubilidad , Motilidad EspermáticaRESUMEN
PURPOSE: Allergic rhinitis (AR) is a common chronic disease. Many factors could affect the development of AR. We investigated early-life factors, such as delivery mode, feeding method, and use of antibiotics during infancy, which could affect the development of AR. In addition, how interactions between these factors and innate gene polymorphisms influence the development of AR was investigated. METHODS: A cross-sectional study of 1,828 children aged 9-12 years was conducted. Three early-life factors and AR were assessed by a questionnaire. Skin prick tests were done. Polymorphisms of TLR4 (rs1927911) and CD14 (rs2569190) were genotyped. RESULTS: Use of antibiotics during infancy increased the risk of AR (aOR [95% CI] 1.511 [1.222-2.037]) and atopic AR (aOR [95% CI], 1.565 [1.078-2.272]). There were synergistic interactions between caesarean delivery, formula feeding, and use of antibiotics in the rate of atopic AR (aOR [95% CI], 3.038 [1.256-7.347]). Additional analyses revealed that the risk for the development of AR or atopic AR subjects with the TLR4 CC genotype were highest when all the 3 early-life factors were present (aOR [95% CI], 5.127 [1.265-20.780] for AR; 6.078 [1.499-24.649] for atopic AR). In addition, the risk for the development of AR or atopic AR in subjects with the CD14 TT genotype were highest when all the 3 early-life factors were present (aOR [95% CI], 5.960 [1.421-15.002] for AR; 6.714 [1.440-31.312] for atopic AR). CONCLUSIONS: Delivery mode, feeding method, and use of antibiotics during infancy appeared to have synergistic interactions in the development of AR. Gene-environment interactions between polymorphism of innate genes and early- life risk factors might affect the development of AR.
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A successful pregnancy depends on a complex process that establishes fetomaternal tolerance. Seminal plasma is known to induce maternal immune tolerance to paternal alloantigens, but the seminal factors that regulate maternal immunity have yet to be characterized. Here, we show that a soluble form of CD38 (sCD38) released from seminal vesicles to the seminal plasma plays a crucial role in inducing tolerogenic dendritic cells and CD4(+) forkhead box P3(+) (Foxp3(+)) regulatory T cells (Tregs), thereby enhancing maternal immune tolerance and protecting the semiallogeneic fetus from resorption. The abortion rate in BALB/c females mated with C57BL/6 Cd38(-/-) males was high compared with that in females mated with Cd38(+/+) males, and this was associated with a reduced proportion of Tregs within the CD4(+) T-cell pool. Direct intravaginal injection of sCD38 to CBA/J pregnant mice at preimplantation increased Tregs and pregnancy rates in mice under abortive sonic stress from 48 h after mating until euthanasia. Thus, sCD38 released from seminal vesicles to the seminal plasma acts as an immunoregulatory factor to protect semiallogeneic fetuses from maternal immune responses.
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ADP-Ribosil Ciclasa 1/inmunología , Tolerancia Inmunológica , Intercambio Materno-Fetal , Semen/inmunología , ADP-Ribosil Ciclasa 1/genética , Animales , Células Dendríticas/inmunología , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , EmbarazoRESUMEN
Muscle contraction and insulin induce glucose uptake in skeletal muscle through GLUT4 membrane translocation. Beneficial effects of exercise on glucose homeostasis in insulin-resistant individuals are known to be due to their distinct mechanism between contraction and insulin action on glucose uptake in skeletal muscle. However, the underlying mechanisms are not clear. Here we show that in skeletal muscle, distinct Ca(2+) second messengers regulate GLUT4 translocation by contraction and insulin treatment; d-myo-inositol 1,4,5-trisphosphate/nicotinic acid adenine dinucleotide phosphate (NAADP) and cyclic ADP-ribose/NAADP are main players for insulin- and contraction-induced glucose uptake, respectively. Different patterns of phosphorylation of AMPK and Ca(2+)/calmodulin-dependent protein kinase II were shown in electrical stimuli (ES)- and insulin-induced glucose uptake pathways. ES-induced Ca(2+) signals and glucose uptake are dependent on glycolysis, which influences formation of NAD(P)-derived signaling messengers, whereas insulin-induced signals are not. High-fat diet (HFD) induced a defect in only insulin-mediated, but not ES-mediated, Ca(2+) signaling for glucose uptake, which is related to a specifically lower NAADP formation. Exercise decreases blood glucose levels in HFD-induced insulin resistance mice via NAADP formation. Thus we conclude that different usage of Ca(2+) signaling in contraction/insulin-stimulated glucose uptake in skeletal muscle may account for the mechanism by which exercise ameliorates glucose homeostasis in individuals with type 2 diabetes.
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Señalización del Calcio/fisiología , Transportador de Glucosa de Tipo 4/metabolismo , Resistencia a la Insulina/fisiología , Insulina/metabolismo , Músculo Esquelético/metabolismo , Condicionamiento Físico Animal/fisiología , Animales , Transporte Biológico/fisiología , Calcio/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Glucosa/metabolismo , Masculino , Ratones , Fosforilación , Transducción de Señal/fisiologíaRESUMEN
H1 linker histone proteins are essential for the structural and functional integrity of chromatin and for the fidelity of additional epigenetic modifications. Deletion of H1c, H1d and H1e in mice leads to embryonic lethality by mid-gestation with a broad spectrum of developmental alterations. To elucidate the cellular and molecular mechanisms underlying H1 linker histone developmental functions, we analyzed embryonic stem cells (ESCs) depleted of H1c, H1d and H1e subtypes (H1-KO ESCs) by utilizing established ESC differentiation paradigms. Our study revealed that although H1-KO ESCs continued to express core pluripotency genes and the embryonic stem cell markers, alkaline phosphatase and SSEA1, they exhibited enhanced cell death during embryoid body formation and during specification of mesendoderm and neuroectoderm. In addition, we demonstrated deregulation in the developmental programs of cardiomyocyte, hepatic and pancreatic lineage elaboration. Moreover, ectopic neurogenesis and cardiomyogenesis occurred during endoderm-derived pancreatic but not hepatic differentiation. Furthermore, neural differentiation paradigms revealed selective impairments in the specification and maturation of glutamatergic and dopaminergic neurons with accelerated maturation of glial lineages. These impairments were associated with deregulation in the expression profiles of pro-neural genes in dorsal and ventral forebrain-derived neural stem cell species. Taken together, these experimental observations suggest that H1 linker histone proteins are critical for the specification, maturation and fidelity of organ-specific cellular lineages derived from the three cardinal germ layers.
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Endodermo/metabolismo , Histonas/metabolismo , Mesodermo/metabolismo , Placa Neural/metabolismo , Animales , Diferenciación Celular , Linaje de la Célula , Células Cultivadas , Cuerpos Embrioides/metabolismo , Desarrollo Embrionario , Células Madre Embrionarias/citología , Células Madre Embrionarias/metabolismo , Endodermo/citología , Hepatocitos/citología , Hepatocitos/metabolismo , Histonas/deficiencia , Histonas/genética , Mesodermo/citología , Ratones , Miocitos Cardíacos/citología , Miocitos Cardíacos/metabolismo , Placa Neural/citología , Neurogénesis , TranscriptomaRESUMEN
NAD glycohydrolases (NADases) catalyze the hydrolysis of NAD to ADP-ribose and nicotinamide. Although many members of the NADase family, including ADP-ribosyltransferases, have been cloned and characterized, the structure and function of NADases with pure hydrolytic activity remain to be elucidated. Here, we report the structural and functional characterization of a novel NADase from rabbit reticulocytes. The novel NADase is a glycosylated, glycosylphosphatidylinositol-anchored cell surface protein exclusively expressed in reticulocytes. shRNA-mediated knockdown of the NADase in bone marrow cells resulted in a reduction of erythroid colony formation and an increase in NAD level. Furthermore, treatment of bone marrow cells with NAD, nicotinamide, or nicotinamide riboside, which induce an increase in NAD content, resulted in a significant decrease in erythroid progenitors. These results indicate that the novel NADase may play a critical role in regulating erythropoiesis of hematopoietic stem cells by modulating intracellular NAD.