RESUMEN
The bone marrow adjusts blood cell production to meet physiological demands in response to insults. The spatial organization of normal and stress responses are unknown owing to the lack of methods to visualize most steps of blood production. Here we develop strategies to image multipotent haematopoiesis, erythropoiesis and lymphopoiesis in mice. We combine these with imaging of myelopoiesis1 to define the anatomy of normal and stress haematopoiesis. In the steady state, across the skeleton, single stem cells and multipotent progenitors distribute through the marrow enriched near megakaryocytes. Lineage-committed progenitors are recruited to blood vessels, where they contribute to lineage-specific microanatomical structures composed of progenitors and immature cells, which function as the production sites for each major blood lineage. This overall anatomy is resilient to insults, as it was maintained after haemorrhage, systemic bacterial infection and granulocyte colony-stimulating factor (G-CSF) treatment, and during ageing. Production sites enable haematopoietic plasticity as they differentially and selectively modulate their numbers and output in response to insults. We found that stress responses are variable across the skeleton: the tibia and the sternum respond in opposite ways to G-CSF, and the skull does not increase erythropoiesis after haemorrhage. Our studies enable in situ analyses of haematopoiesis, define the anatomy of normal and stress responses, identify discrete microanatomical production sites that confer plasticity to haematopoiesis, and uncover unprecedented heterogeneity of stress responses across the skeleton.
Asunto(s)
Hematopoyesis , Células Madre Hematopoyéticas , Estrés Fisiológico , Animales , Femenino , Masculino , Ratones , Envejecimiento/fisiología , Infecciones Bacterianas/patología , Infecciones Bacterianas/fisiopatología , Vasos Sanguíneos/citología , Linaje de la Célula , Eritropoyesis , Factor Estimulante de Colonias de Granulocitos/metabolismo , Hematopoyesis/fisiología , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/metabolismo , Hemorragia/patología , Hemorragia/fisiopatología , Linfopoyesis , Megacariocitos/citología , Células Madre Multipotentes/citología , Células Madre Multipotentes/metabolismo , Mielopoyesis , Cráneo/irrigación sanguínea , Cráneo/patología , Cráneo/fisiopatología , Esternón/irrigación sanguínea , Esternón/citología , Esternón/metabolismo , Estrés Fisiológico/fisiología , Tibia/irrigación sanguínea , Tibia/citología , Tibia/metabolismoRESUMEN
Although the stem cells of various tissues remain in the quiescent state to maintain their undifferentiated state, they also undergo cell divisions as required, and if necessary, even a single stem cell is able to provide for lifelong tissue homeostasis. Stem cell populations are precisely controlled by the balance between their symmetric and asymmetric divisions, with their division patterns determined by whether the daughter cells involved retain their self-renewal capacities. Recent studies have reported that metabolic pathways and the distribution of mitochondria are regulators of the division balance of stem cells and that metabolic defects can shift division balance toward symmetric commitment, which leads to stem cell exhaustion. It has also been observed that in asymmetric division, old mitochondria, which are central metabolic organelles, are segregated to the daughter cell fated to cell differentiation, whereas in symmetric division, young and old mitochondria are equally distributed between both daughter cells. Thus, metabolism and mitochondrial biology play important roles in stem cell fate decisions. As these decisions directly affect tissue homeostasis, understanding their regulatory mechanisms in the context of cellular metabolism is critical.
Asunto(s)
Linaje de la Célula , Autorrenovación de las Células , Redes y Vías Metabólicas , Células Madre/citología , Células Madre/metabolismo , Animales , División Celular , Humanos , Mitocondrias/metabolismoRESUMEN
PTEN dysfunction plays a crucial role in the pathogenesis of hereditary and sporadic cancers. Here, we show that PTEN homodimerizes and, in this active conformation, exerts lipid phosphatase activity on PtdIns(3,4,5)P3. We demonstrate that catalytically inactive cancer-associated PTEN mutants heterodimerize with wild-type PTEN and constrain its phosphatase activity in a dominant-negative manner. To study the consequences of homo- and heterodimerization of wild-type and mutant PTEN in vivo, we generated Pten knockin mice harboring two cancer-associated PTEN mutations (PtenC124S and PtenG129E). Heterozygous Pten(C124S/+) and Pten(G129E/+) cells and tissues exhibit increased sensitivity to PI3-K/Akt activation compared to wild-type and Pten(+/-) counterparts, whereas this difference is no longer apparent between Pten(C124S/-) and Pten(-/-) cells. Notably, Pten KI mice are more tumor prone and display features reminiscent of complete Pten loss. Our findings reveal that PTEN loss and PTEN mutations are not synonymous and define a working model for the function and regulation of PTEN.
Asunto(s)
Fosfohidrolasa PTEN/genética , Fosfohidrolasa PTEN/metabolismo , Transducción de Señal , Animales , Embrión de Mamíferos/citología , Femenino , Humanos , Pérdida de Heterocigocidad , Masculino , Ratones , Mutación , Multimerización de Proteína , Proteínas Proto-Oncogénicas c-akt/metabolismoRESUMEN
Decremental loss of PTEN results in cancer susceptibility and tumor progression. PTEN elevation might therefore be an attractive option for cancer prevention and therapy. We have generated several transgenic mouse lines with PTEN expression elevated to varying levels by taking advantage of bacterial artificial chromosome (BAC)-mediated transgenesis. The "Super-PTEN" mutants are viable and show reduced body size due to decreased cell number, with no effect on cell size. Unexpectedly, PTEN elevation at the organism level results in healthy metabolism characterized by increased energy expenditure and reduced body fat accumulation. Cells derived from these mice show reduced glucose and glutamine uptake and increased mitochondrial oxidative phosphorylation and are resistant to oncogenic transformation. Mechanistically we find that PTEN elevation orchestrates this metabolic switch by regulating PI3K-dependent and -independent pathways and negatively impacting two of the most pronounced metabolic features of tumor cells: glutaminolysis and the Warburg effect.
Asunto(s)
Fosfohidrolasa PTEN/metabolismo , Transducción de Señal , Animales , Tamaño Corporal , Recuento de Células , Proliferación Celular , Respiración de la Célula , Metabolismo Energético , Ratones , Ratones Transgénicos , Mitocondrias/metabolismo , Fosfohidrolasa PTEN/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismoRESUMEN
A distinctive feature of stem cells is their capacity to self-renew to maintain pluripotency. Studies of genetically-engineered mouse models and recent advances in metabolomic analysis, particularly in haematopoietic stem cells, have deepened our understanding of the contribution made by metabolic cues to the regulation of stem cell self-renewal. Many types of stem cells heavily rely on anaerobic glycolysis, and stem cell function is also regulated by bioenergetic signalling, the AKT-mTOR pathway, Gln metabolism and fatty acid metabolism. As maintenance of a stem cell pool requires a finely-tuned balance between self-renewal and differentiation, investigations into the molecular mechanisms and metabolic pathways underlying these decisions hold great therapeutic promise.
Asunto(s)
Diferenciación Celular , Metabolismo Energético , Células Madre/citología , Células Madre/metabolismo , Animales , Humanos , Ratones , Transducción de SeñalRESUMEN
In homeostasis, whether blood cells are derived from committed progenitor or mutipotent stem cell activity remains controversial. In this issue of Immunity, Sawai et al. (2016) describe murine HSCs as the major contributor to the maintenance of multilineage hematopoiesis, both in the steady state and during cytokine response.
Asunto(s)
Hematopoyesis/fisiología , Células Madre Hematopoyéticas/fisiología , Animales , Diferenciación Celular/fisiología , Citocinas/metabolismo , Células Madre Hematopoyéticas/metabolismo , Homeostasis/fisiología , HumanosRESUMEN
Cytolytic ETosis is a type of programmed cell death distinct from apoptosis and necrosis and plays a major role in the innate immune system and disease progression. Through the process of ETosis, cells release their chromatin with diverse antimicrobial proteins into the extracellular milieu, forming extracellular traps (ETs). Although ETosis has been reported in several leukocyte types, few studies have compared ETosis and the component proteins of ETs in leukocytes. The aim of this study was to better understand the characteristics of eosinophil ETosis (EETosis) compared with other leukocytes. We isolated human blood eosinophils, neutrophils, basophils, monocytes, and lymphocytes and stimulated them with known ETosis inducers, a protein kinase C activator PMA, or a calcium ionophore A23187. Both stimuli induced eosinophil cell death and ET release after 180 minutes of stimulation in a NADPH-oxidase-dependent manner. PMA also induced NADPH-oxidase-dependent ETosis in neutrophils, whereas little or no significant ETosis was observed in basophils, monocytes, or lymphocytes at 180 minutes. Mass spectrometry-based proteomic analysis of eosinophil- and neutrophil-derived ETs identified 997 and 1415 proteins, respectively. Among the physiological stimuli tested, immobilized IgA and IgG induced EETosis. C-C motif chemokine ligand 11 (CCL11) and interleukin 5 (IL-5) were weak inducers of EETosis, but co-stimulation significantly induced rapid EETosis. Under high serum or albumin conditions, co-stimulation with CCL11 and IL-5 paradoxically prolonged cell survival by preventing spontaneous apoptosis. This study provides an in-depth characterization of EETosis and highlights the precise regulation of eosinophil survival and cell death pathways.
RESUMEN
Given that the corneal epithelium is situated on the outermost part of the eye, its functions can be influenced by external temperatures and chemical substances. This study aimed to elucidate the expression profile of chemosensory receptors in corneal epithelial cells and analyze their role in eye function regulation. A comprehensive analysis of 425 chemosensory receptors in human corneal epithelial cells-transformed (HCE-T) revealed the functional expression of TRPV4. The activation of TRPV4 in HCE-T cells significantly increased the expression of membrane-associated mucins MUC1, MUC4, and MUC16, which are crucial for stabilizing tear films, with efficacy comparable to the active components of dry eye medications. The present study suggests that TRPV4, which is activated by body temperature, regulates mucin expression and proposes it as a novel target for dry eye treatment.
Asunto(s)
Epitelio Corneal , Mucina 4 , Canales Catiónicos TRPV , Humanos , Canales Catiónicos TRPV/metabolismo , Canales Catiónicos TRPV/genética , Epitelio Corneal/metabolismo , Epitelio Corneal/citología , Mucina 4/metabolismo , Mucina 4/genética , Mucina-1/metabolismo , Mucina-1/genética , Antígeno Ca-125/metabolismo , Antígeno Ca-125/genética , Mucinas/metabolismo , Mucinas/biosíntesis , Células Epiteliales/metabolismo , Células Epiteliales/citología , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genéticaRESUMEN
Myelodysplastic syndrome (MDS) is characterized by ineffective hematopoiesis with morphologic dysplasia and a propensity to transform into overt acute myeloid leukemia (AML). Our analysis of two cohorts of 20 MDS and 49 AML with multi-lineage dysplasia patients shows a reduction in Nucleophosmin 1 (NPM1) expression in 70% and 90% of cases, respectively. A mouse model of Npm1 conditional knockout (cKO) in hematopoietic cells reveals that Npm1 loss causes premature aging of hematopoietic stem cells (HSCs). Mitochondrial activation in Npm1-deficient HSCs leads to aberrant activation of the NLRP3 inflammasome, which correlates with a developing MDS-like phenotype. Npm1 cKO mice exhibit shortened survival times, and expansion of both the intra- and extra-medullary myeloid populations, while evoking a p53-dependent response. After transfer into a p53 mutant background, the resulting Npm1/p53 double KO mice develop fatal leukemia within 6 months. Our findings identify NPM1 as a regulator of HSC aging and inflammation and highlight the role of p53 in MDS progression to leukemia.
Asunto(s)
Leucemia Mieloide Aguda , Síndromes Mielodisplásicos , Envejecimiento/genética , Animales , Células Madre Hematopoyéticas/metabolismo , Humanos , Inflamación/genética , Inflamación/metabolismo , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Ratones , Mutación , Síndromes Mielodisplásicos/complicaciones , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Nucleofosmina , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Eosinophilic inflammation is primarily characterized by type 2 immune responses against parasitic organisms. In the contemporary human being especially in developed countries, eosinophilic inflammation is strongly associated with allergic/sterile inflammation, and constitutes an undesired immune reaction. This situation is in stark contrast to neutrophilic inflammation, which is indispensable for the host defense against bacterial infections. Among eosinophilic inflammatory disorders, massive accumulation of eosinophils within mucus is observed in certain cases, and is often linked to the distinctive clinical finding of mucus with high viscosity. Eosinophilic mucus is found in a variety of diseases, including chronic allergic keratoconjunctivitis, chronic rhinosinusitis encompassing allergic fungal sinusitis, eosinophilic otitis media, eosinophilic sialodochitis, allergic bronchopulmonary aspergillosis/mycosis, eosinophilic plastic bronchitis, and eosinophilic asthma. In these pathological conditions, chronic inflammation and tissue remodeling coupled with irreversible organ damage due to persistent adhesion of toxic substances and luminal obstruction may impose a significant burden on the body. Eosinophils aggregate in the hyperconcentrated mucus together with cell-derived crystals, macromolecules, and polymers, thereby affecting the biophysical properties of the mucus. This review focuses on the clinically significant challenges of mucus and discusses the consequences of activated eosinophils on the mucosal surface that impact mucus and persistent inflammation.
Asunto(s)
Eosinofilia , Eosinófilos , Moco , Humanos , Eosinofilia/inmunología , Moco/metabolismo , Eosinófilos/inmunología , Animales , Sinusitis/inmunologíaRESUMEN
The enteric nervous system (ENS) regulates gut functions independently from the central nervous system (CNS) by its highly autonomic neural circuit that integrates diverse neuronal subtypes. Although several transcription factors are shown to be necessary for the generation of some enteric neuron subtypes, the mechanisms underlying neuronal subtype specification in the ENS remain elusive. In this study, we examined the biological function of Polycomb group RING finger protein 1 (PCGF1), one of the epigenetic modifiers, in the development and differentiation of the ENS by disrupting the Pcgf1 gene selectively in the autonomic-lineage cells. Although ENS precursor migration and enteric neurogenesis were largely unaffected, neuronal differentiation was impaired in the Pcgf1-deficient mice, with the numbers of neurons expressing somatostatin (Sst+ ) decreased in multiple gut regions. Notably, the decrease in Sst+ neurons was associated with the corresponding increase in calbindin+ neurons in the proximal colon. These findings suggest that neuronal subtype conversion may occur in the absence of PCGF1, and that epigenetic mechanism is primarily involved in specification of some enteric neuron subtypes.
Asunto(s)
Sistema Nervioso Entérico , Neuronas , Animales , Ratones , Diferenciación Celular/genética , Factores de Transcripción/metabolismo , Sistema Nervioso Entérico/metabolismo , Epigénesis Genética , Complejo Represivo Polycomb 1/genética , Complejo Represivo Polycomb 1/metabolismoRESUMEN
Cadmium is an environmental pollutant that adversely affects various organs in the human body and is a well-known risk factor for cardiovascular diseases. These disorders are caused by the dysfunction of the vascular endothelial cells that cover the luminal surface of blood vessels. The ZIP transporter ZIP8 is one of the primary importers of cadmium, and its expression appears to be important for the sensitivity of vascular endothelial cells to cadmium. In the present study, we investigated the influence of ZIP8 on cadmium-induced cytotoxicity in vascular endothelial cells, the induction of ZIP8 expression by cadmium, and its action mechanism in vascular endothelial cells. The study revealed that: (1) cadmium cytotoxicity in vascular endothelial cells was potentiated by the overexpression of ZIP8, and the intracellular accumulation of cadmium in the cells was increased; (2) cadmium highly induced the expression of ZIP8, but not other ZIPs; (3) lead and methylmercury moderately induced ZIP8 expression, but the other tested metals did not; (4) the induction of ZIP8 expression by cadmium was mediated by both NF-κB and JNK signaling, and the accumulation of NF-κB in the nucleus was regulated by JNK signaling. Particularly, it was found that cadmium activated NF-κB to transfer it into nuclei and activated JNK to stabilize NF-κB in nuclei, resulting in the induction of ZIP8 expression. This induction appears to be crucial for cadmium cytotoxicity in vascular endothelial cells.
Asunto(s)
Cadmio/toxicidad , Proteínas de Transporte de Catión/metabolismo , MAP Quinasa Quinasa 4/metabolismo , Inhibidor NF-kappaB alfa/metabolismo , FN-kappa B/metabolismo , Animales , Proteínas de Transporte de Catión/genética , Bovinos , Células Cultivadas , Células Endoteliales , Contaminantes Ambientales , Factor 2 de Crecimiento de Fibroblastos , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , MAP Quinasa Quinasa 4/genética , Inhibidor NF-kappaB alfa/genética , FN-kappa B/genética , Transducción de SeñalRESUMEN
The GDNF Family Ligands (GFLs) regulate neural development and kidney organogenesis by activating the RET receptor tyrosine kinase. Many RET-dependent developmental processes involve long-distance cell-cell communications or cell polarity, which includes cell migration and axon guidance. This suggests that spatiotemporally regulated subcellular localization of RET protein and appropriate propagation of RET signaling in cells are essential for the physiological function of the GFLs. Little is known, however, about the dynamics of RET protein in cells. Addressing this issue requires development of a system that allows visualization of RET in living cells. In this study, we report generation of a novel knock-in mouse line in which the RET-EGFP chimeric receptor is expressed under the Ret promoter. Unlike Ret-deficient mice that die after birth due to the absence of the enteric nervous system (ENS) and kidneys, RetRET-EGFP/RET-EGFP mice were viable and grew to adulthood with no overt abnormality, which indicated that RET-EGFP exerts function comparable to RET. In neurons and ENS progenitors, RET-EGFP signals were detected both on the cell membrane and in the cytoplasm, the latter of which appeared as a punctate pattern. Time-lapse imaging of cultured neural cells and embryos revealed active transport of RET-EGFP puncta in neuronal axons and cell bodies. Immunohistochemical analyses detected RET-EGFP signals in early and recycling endosomes, indicating that RET-EGFP is trafficked via the endocytic pathway. RetRET-EGFP/RET-EGFP mice enable visualization of functional RET protein in vivo for the first time and provide a unique platform to examine the dynamics and physiology of RET trafficking.
Asunto(s)
Sistema Nervioso Entérico , Factor Neurotrófico Derivado de la Línea Celular Glial , Animales , Movimiento Celular , Factor Neurotrófico Derivado de la Línea Celular Glial/genética , Ratones , Neuronas , Transducción de SeñalRESUMEN
1'-Acetoxychavicol acetate (ACA) is found in Thai ginger (Alpinia galanga) and is a powerful agonist of transient receptor potential ankyrin 1 (TRPA1). In a diet-induced obesity mouse model, ACA reduced fat deposition. Sympathetic nerve activation was also indicated in the ACA-fed group. This study is expected to promote the utilization of food containing TRPA1 agonists to treat obesity.
Asunto(s)
Alcoholes Bencílicos , Animales , Ancirinas , Zingiber officinale , Grasa Intraabdominal , RatonesRESUMEN
The uptake of di/tripeptides is mediated by the proton-dependent oligopeptide transporter (POT) family. In this study, 3 POT family transporters, designated PotA, PotB, and PotC were identified in Aspergillus oryzae. Growth comparison of deletion mutants of these transporter genes suggested that PotB and PotC are responsible for di/tripeptide uptake. PotA, which had the highest sequence similarity to yeast POT (Ptr2), contributed little to the uptake. Nitrogen starvation induced potB and potC expression, but not potA expression. When 3 dipeptides were provided as nitrogen sources, the expression profiles of these genes were different. PrtR, a transcription factor that regulates proteolytic genes, was involved in regulation of potA and potB but not in potC expression. Only potC expression levels were dramatically reduced by disruption of ubrA, an orthologue of yeast ubiquitin ligase UBR1 responsible for PTR2 expression. Expression of individual POT genes is apparently controlled by different regulatory mechanisms.
Asunto(s)
Aspergillus oryzae/genética , Aspergillus oryzae/metabolismo , Dipéptidos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Regulación Fúngica de la Expresión Génica , Transporte de Proteínas , Proteínas de Saccharomyces cerevisiae/genéticaRESUMEN
Humans sense taste and smell of various chemical substances through approximately 430 chemosensory receptors. The overall picture of ligand-chemosensory receptor interactions has been partially clarified because of numerous interactions. This study presents a new method that enables a rapid and simple screening of chemosensory receptors. It would be useful for identifying chemosensory receptors activated by taste and odor substances.
Asunto(s)
Evaluación Preclínica de Medicamentos/métodos , Percepción Olfatoria/efectos de los fármacos , Percepción del Gusto/efectos de los fármacosRESUMEN
Many functional food ingredients activate human bitter taste receptors (hTAS2Rs). In this study, A novel inhibitor, Trp-Trp, for hTAS2R14 was identified by searching for the agonist peptide's analogs. Trp-Trp also inhibited hTAS2R16, hTAS2R43, and hTAS2R46, which share the same agonists with hTAS2R14. The multifunctional characteristic of Trp-Trp is advantageous for use as bitterness-masking agents in functional foods.
Asunto(s)
Dipéptidos/farmacología , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Alimentos Funcionales/análisis , Humanos , Gusto/efectos de los fármacosRESUMEN
Mitochondrial dysfunction and stem cell exhaustion are two hallmarks of aging. In the hematopoietic system, aging is linked to imbalanced immune response and reduced regenerative capacity in hematopoietic stem cells (HSCs), as well as an increased predisposition to a spectrum of diseases, including myelodysplastic syndrome and acute myeloid leukemia. Myeloid-biased differentiation and loss of polarity are distinct features of aged HSCs, which generally exhibit enhanced mitochondrial oxidative phosphorylation and increased production of reactive oxygen species (ROS), suggesting a direct role for mitochondria in the degenerative process. Here, we provide an overview of current knowledge of the mitochondrial mechanisms that contribute to age-related phenotypes in HSCs. These include mitochondrial ROS production, alteration/activation of mitochondrial metabolism, the quality control pathway of mitochondria, and inflammation. Greater understanding of the key machineries of HSC aging will allow us to identify new therapeutic targets for preventing, delaying, or even reversing aspects of this process.
Asunto(s)
Senescencia Celular/fisiología , Células Madre Hematopoyéticas/fisiología , Mitocondrias/fisiología , Animales , Diferenciación Celular/efectos de los fármacos , Senescencia Celular/efectos de los fármacos , Hematopoyesis/efectos de los fármacos , Hematopoyesis/fisiología , Células Madre Hematopoyéticas/efectos de los fármacos , Células Madre Hematopoyéticas/metabolismo , Humanos , Mitocondrias/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Especies Reactivas de Oxígeno/farmacologíaRESUMEN
Vascular endothelial cells cover the luminal surface of blood vessels in a monolayer and play a role in the regulation of vascular functions, such as the blood coagulation-fibrinolytic system. When the monolayer is severely or repeatedly injured, platelets aggregate at the damaged site and release transforming growth factor (TGF)-ß1 in large quantities from their α-granules. Cadmium is a heavy metal that is toxic to various organs, including the kidneys, bones, liver, and blood vessels. Our previous study showed that the expression level of Zrt/Irt-related protein 8 (ZIP8), a metal transporter that transports cadmium from the extracellular fluid into the cytosol, is a crucial factor in determining the sensitivity of vascular endothelial cells to cadmium cytotoxicity. In the present study, TGF-ß1 was discovered to potentiate cadmium-induced cytotoxicity by increasing the intracellular accumulation of cadmium in cells. Additionally, TGF-ß1 induced the expression of ZIP8 via the activin receptor-like kinase 5-Smad2/3 signaling pathways; Smad3-mediated induction of ZIP8 was associated with or without p38 mitogen-activated protein kinase (MAPK). These results suggest that the cytotoxicity of cadmium to vascular endothelial cells increases when damaged endothelial monolayers that are highly exposed to TGF-ß1 are repaired.