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Germline histone H3.3 amino acid substitutions, including H3.3G34R/V, cause severe neurodevelopmental syndromes. To understand how these mutations impact brain development, we generated H3.3G34R/V/W knock-in mice and identified strikingly distinct developmental defects for each mutation. H3.3G34R-mutants exhibited progressive microcephaly and neurodegeneration, with abnormal accumulation of disease-associated microglia and concurrent neuronal depletion. G34R severely decreased H3K36me2 on the mutant H3.3 tail, impairing recruitment of DNA methyltransferase DNMT3A and its redistribution on chromatin. These changes were concurrent with sustained expression of complement and other innate immune genes possibly through loss of non-CG (CH) methylation and silencing of neuronal gene promoters through aberrant CG methylation. Complement expression in G34R brains may lead to neuroinflammation possibly accounting for progressive neurodegeneration. Our study reveals that H3.3G34-substitutions have differential impact on the epigenome, which underlie the diverse phenotypes observed, and uncovers potential roles for H3K36me2 and DNMT3A-dependent CH-methylation in modulating synaptic pruning and neuroinflammation in post-natal brains.
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ADN Metiltransferasa 3A , Histonas , Animales , Ratones , ADN (Citosina-5-)-Metiltransferasas/genética , Metilación de ADN/genética , Metilasas de Modificación del ADN/genética , Histonas/metabolismo , Enfermedades NeuroinflamatoriasRESUMEN
Histone H3.3 glycine 34 to arginine/valine (G34R/V) mutations drive deadly gliomas and show exquisite regional and temporal specificity, suggesting a developmental context permissive to their effects. Here we show that 50% of G34R/V tumors (n = 95) bear activating PDGFRA mutations that display strong selection pressure at recurrence. Although considered gliomas, G34R/V tumors actually arise in GSX2/DLX-expressing interneuron progenitors, where G34R/V mutations impair neuronal differentiation. The lineage of origin may facilitate PDGFRA co-option through a chromatin loop connecting PDGFRA to GSX2 regulatory elements, promoting PDGFRA overexpression and mutation. At the single-cell level, G34R/V tumors harbor dual neuronal/astroglial identity and lack oligodendroglial programs, actively repressed by GSX2/DLX-mediated cell fate specification. G34R/V may become dispensable for tumor maintenance, whereas mutant-PDGFRA is potently oncogenic. Collectively, our results open novel research avenues in deadly tumors. G34R/V gliomas are neuronal malignancies where interneuron progenitors are stalled in differentiation by G34R/V mutations and malignant gliogenesis is promoted by co-option of a potentially targetable pathway, PDGFRA signaling.
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Neoplasias Encefálicas/genética , Carcinogénesis/genética , Glioma/genética , Histonas/genética , Interneuronas/metabolismo , Mutación/genética , Células-Madre Neurales/metabolismo , Receptor alfa de Factor de Crecimiento Derivado de Plaquetas/genética , Animales , Astrocitos/metabolismo , Astrocitos/patología , Neoplasias Encefálicas/patología , Carcinogénesis/patología , Linaje de la Célula , Reprogramación Celular/genética , Cromatina/metabolismo , Embrión de Mamíferos/metabolismo , Epigénesis Genética , Regulación Neoplásica de la Expresión Génica , Silenciador del Gen , Glioma/patología , Histonas/metabolismo , Lisina/metabolismo , Ratones Endogámicos C57BL , Modelos Biológicos , Clasificación del Tumor , Oligodendroglía/metabolismo , Regiones Promotoras Genéticas/genética , Prosencéfalo/embriología , Receptor alfa de Factor de Crecimiento Derivado de Plaquetas/metabolismo , Transcripción Genética , Transcriptoma/genéticaRESUMEN
Individuals from different populations vary considerably in their susceptibility to immune-related diseases. To understand how genetic variation and natural selection contribute to these differences, we tested for the effects of African versus European ancestry on the transcriptional response of primary macrophages to live bacterial pathogens. A total of 9.3% of macrophage-expressed genes show ancestry-associated differences in the gene regulatory response to infection, and African ancestry specifically predicts a stronger inflammatory response and reduced intracellular bacterial growth. A large proportion of these differences are under genetic control: for 804 genes, more than 75% of ancestry effects on the immune response can be explained by a single cis- or trans-acting expression quantitative trait locus (eQTL). Finally, we show that genetic effects on the immune response are strongly enriched for recent, population-specific signatures of adaptation. Together, our results demonstrate how historical selective events continue to shape human phenotypic diversity today, including for traits that are key to controlling infection.
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Histone H3.3 lysine-to-methionine substitutions K27M and K36M impair the deposition of opposing chromatin marks, H3K27me3/me2 and H3K36me3/me2. We show that these mutations induce hypotrophic and disorganized eyes in Drosophila eye primordia. Restriction of H3K27me3 spread in H3.3K27M and its redistribution in H3.3K36M result in transcriptional deregulation of PRC2-targeted eye development and of piRNA biogenesis genes, including krimp. Notably, both mutants promote redistribution of H3K36me2 away from repetitive regions into active genes, which associate with retrotransposon de-repression in eye discs. Aberrant expression of krimp represses LINE retrotransposons but does not contribute to the eye phenotype. Depletion of H3K36me2 methyltransferase ash1 in H3.3K27M, and of PRC2 component E(z) in H3.3K36M, restores the expression of eye developmental genes and normal eye growth, showing that redistribution of antagonistic marks contributes to K-to-M pathogenesis. Our results implicate a novel function for H3K36me2 and showcase convergent downstream effects of oncohistones that target opposing epigenetic marks.
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Cromatina/química , Elementos Transponibles de ADN , Histonas/química , Histonas/genética , Discos Imaginales/metabolismo , Mutación , Animales , Animales Modificados Genéticamente , Centrómero/ultraestructura , Inmunoprecipitación de Cromatina , Biología Computacional/métodos , Metilación de ADN , Drosophila melanogaster , Epigénesis Genética , Humanos , Lisina/química , Metionina/química , Ratones , Microscopía Electrónica de Rastreo , Microscopía Fluorescente , Fenotipo , RNA-SeqRESUMEN
The genetic alterations contributing to migration proficiency, a phenotypic hallmark of metastatic cells required for colonizing distant organs, remain poorly defined. Here, we used single-cell magneto-optical capture (scMOCa) to isolate fast cells from heterogeneous human breast cancer cell populations, based on their migratory ability alone. We show that captured fast cell subpopulations retain higher migration speed and focal adhesion dynamics over many generations as a result of a motility-related transcriptomic profile. Upregulated genes in isolated fast cells encoded integrin subunits, proto-cadherins and numerous other genes associated with cell migration. Dysregulation of several of these genes correlates with poor survival outcomes in people with breast cancer, and primary tumors established from fast cells generated a higher number of circulating tumor cells and soft tissue metastases in pre-clinical mouse models. Subpopulations of cells selected for a highly migratory phenotype demonstrated an increased fitness for metastasis.
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Neoplasias de la Mama , Células Neoplásicas Circulantes , Animales , Ratones , Humanos , Femenino , Neoplasias de la Mama/patología , Línea Celular Tumoral , Células Neoplásicas Circulantes/patología , Movimiento Celular/genética , Cadherinas , Metástasis de la NeoplasiaRESUMEN
The contribution of deregulated chromatin architecture, including topologically associated domains (TADs), to cancer progression remains ambiguous. CCCTC-binding factor (CTCF) is a central regulator of higher-order chromatin structure that undergoes copy number loss in over half of all breast cancers, but the impact of this defect on epigenetic programming and chromatin architecture remains unclear. We find that under physiological conditions, CTCF organizes subTADs to limit the expression of oncogenic pathways, including phosphatidylinositol 3-kinase (PI3K) and cell adhesion networks. Loss of a single CTCF allele potentiates cell invasion through compromised chromatin insulation and a reorganization of chromatin architecture and histone programming that facilitates de novo promoter-enhancer contacts. However, this change in the higher-order chromatin landscape leads to a vulnerability to inhibitors of mTOR. These data support a model whereby subTAD reorganization drives both modification of histones at de novo enhancer-promoter contacts and transcriptional up-regulation of oncogenic transcriptional networks.
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Ensamble y Desensamble de Cromatina , Regulación Neoplásica de la Expresión Génica , Invasividad Neoplásica , Factor de Unión a CCCTC/metabolismo , Carcinogénesis/genética , Cromatina/genética , Cromatina/metabolismo , Humanos , Invasividad Neoplásica/genética , Invasividad Neoplásica/patología , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Regiones Promotoras GenéticasRESUMEN
Translational control of gene expression is an important regulator of adult stem cell quiescence, activation and self-renewal. In skeletal muscle, quiescent satellite cells maintain low levels of protein synthesis, mediated in part through the phosphorylation of eIF2α (P-eIF2α). Pharmacological inhibition of the eIF2α phosphatase with the small molecule sal003 maintains P-eIF2α and permits the expansion of satellite cells ex vivo Paradoxically, P-eIF2α also increases the translation of specific mRNAs, which is mediated by P-eIF2α-dependent read-through of inhibitory upstream open reading frames (uORFs). Here, we ask whether P-eIF2α-dependent mRNA translation enables expansion of satellite cells. Using transcriptomic and proteomic analyses, we show a number of genes associated with the assembly of the spindle pole to be upregulated at the level of protein, without corresponding change in mRNA levels, in satellite cells expanded in the presence of sal003. We show that uORFs in the 5' UTR of mRNA for the mitotic spindle stability gene Tacc3 direct P-eIF2α-dependent translation. Satellite cells deficient for TACC3 exhibit defects in expansion, self-renewal and regeneration of skeletal muscle.
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Factor 2 Eucariótico de Iniciación/metabolismo , Proteínas Fetales/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Biosíntesis de Proteínas , Células Satélite del Músculo Esquelético/citología , Células Satélite del Músculo Esquelético/metabolismo , Animales , Diferenciación Celular/genética , Proliferación Celular , Autorrenovación de las Células , Células Cultivadas , Regulación hacia Abajo/genética , Ratones Endogámicos C57BL , Factor de Transcripción PAX7/metabolismo , Fosforilación , Proteoma/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Regeneración , Transcriptoma/genética , Regulación hacia Arriba/genéticaRESUMEN
Romk knock-out mice show a similar phenotype to Bartter syndrome of salt wasting and dehydration due to reduced Na-K-2Cl-cotransporter activity. At least three ROMK isoforms have been identified in the kidney; however, unique functions of any of the isoforms in nephron segments are still poorly understood. We have generated a mouse deficient only in Romk1 by selective deletion of the Romk1-specific first exon using an ES cell Cre-LoxP strategy and examined the renal phenotypes, ion transporter expression, ROMK channel activity, and localization under normal and high K intake. Unlike Romk(-/-) mice, there was no Bartter phenotype with reduced NKCC2 activity and increased NCC expression in Romk1(-/-) mice. The small conductance K channel (SK) activity showed no difference of channel properties or gating in the collecting tubule between Romk1(+/+) and Romk1(-/-) mice. High K intake increased SK channel number per patch and increased the ROMK channel intensity in the apical membrane of the collecting tubule in Romk1(+/+), but such regulation by high K intake was diminished with significant hyperkalemia in Romk1(-/-) mice. We conclude that 1) animal knockouts of ROMK1 do not produce Bartter phenotype. 2) There is no functional linking of ROMK1 and NKCC2 in the TAL. 3) ROMK1 is critical in response to high K intake-stimulated K(+) secretion in the collecting tubule.
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Síndrome de Bartter/genética , Canales de Potasio de Rectificación Interna/metabolismo , Potasio/metabolismo , Animales , Células Cultivadas , Eliminación de Gen , Activación del Canal Iónico , Túbulos Renales Colectores/citología , Túbulos Renales Colectores/metabolismo , Ratones , Fenotipo , Canales de Potasio de Rectificación Interna/genética , Sodio/metabolismo , Miembro 1 de la Familia de Transportadores de Soluto 12/metabolismoRESUMEN
Background As part of the 2007 health reform in Germany the structure of outpatient palliative care for children and adolescents was adopted for the first time and then implemented in Erlangen-Nuremberg in 2009. Methods The introduction of Pediatric Palliative Home Care (PPHC) at the Hospital for Children and Adolescents at the University of Erlangen-Nuremberg was retrospectively analyzed between the years 2009 to 2014. Referring medical records (paper-based and electronic) were evaluated systematically. Results Considering 69 patients within this study, 44 (63.8%) died during the investigated period and 61% of these Patients deceased at home. 60 patients (87%) had a written emergency plan, which was jointly developed with patients and particularly their parents and relatives in cooperation with the PPHC team. Over the years and with increasing experience, the number and duration of emergency hospitalization decreased. Even complex therapies, such as patient-controlled analgesia with PCA pump could be implemented on an outpatient basis. Conclusion The descriptive cohort study demonstrates that palliative care for children, despite the medical and structural complexity is possible in an ambulatory setting. It allows a similar, if not better care, compared to inpatient palliative care for children and adolescents, not only for the affected patients, but also for their families.
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Servicios de Atención a Domicilio Provisto por Hospital/organización & administración , Hospitales Urbanos , Cuidados Paliativos/organización & administración , Adolescente , Niño , Preescolar , Femenino , Alemania , Reforma de la Atención de Salud/organización & administración , Implementación de Plan de Salud/organización & administración , Implementación de Plan de Salud/estadística & datos numéricos , Servicios de Atención a Domicilio Provisto por Hospital/estadística & datos numéricos , Hospitales Pediátricos/estadística & datos numéricos , Hospitales Urbanos/estadística & datos numéricos , Humanos , Masculino , Cuidados Paliativos/estadística & datos numéricos , Readmisión del Paciente/estadística & datos numéricos , Análisis de SupervivenciaRESUMEN
Achondroplasia is the most common skeletal dysplasia and is associated with serious complications such as foramen magnum stenosis (FMS). This case report describes an infant with achondroplasia who presented with a syndrome of inappropriate antidiuretic hormone secretion (SIADH), secondary to significant FMS and myelocompression. A 2-month-old boy with prenatally diagnosed achondroplasia was referred due to disordered breathing and altered consciousness. On admission, apathy, hypotonus, and hypothermia with typical features of achondroplasia were noticed. Laboratory investigations revealed severe hyponatremia and hypochloridaemia with normal glucose and urea levels. The diagnosis of SIADH was made based on low serum osmolality in the presence of high urine osmolality, along with an elevated copeptin level. An emergency computerized tomography showed a high-grade stenosis at the cranio-cervical junction; subsequent magnetic resonance imaging demonstrated myelocompression. The patient underwent decompression surgery the next day; serum osmolality increased after the operation. Spontaneous breathing after extubation was sufficient whereas tetraplegia persisted despite intensive physiotherapy. Clinicians should be aware of SIADH as a presenting sign of FMS in children with achondroplasia. Further discussion is warranted regarding improving parental education and timing of screening recommendations.
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The pogo transposable element derived zinc finger protein, POGZ, is notably associated with neurodevelopmental disorders through its role in gene transcription. Many proteins involved in neurological development are often dysregulated in cancer, suggesting a potential role for POGZ in tumor biology. Here, we provided experimental evidence that POGZ influences the growth and metastatic spread of triple negative breast cancers (TNBC). In well-characterized models of TNBC, POGZ exerted a dual role, both as a tumor promoter and metastasis suppressor. Mechanistically, loss of POGZ potentiated TGFß pathway activation to exert cytostatic effects while simultaneously increasing the mesenchymal and migratory properties of breast tumors. Whereas POGZ levels are elevated in human breast cancers, the most aggressive forms of TNBC tumors, including those with increased mesenchymal and metastatic properties, exhibit dampened POGZ levels, and low POGZ expression was associated with inferior clinical outcomes in these tumor types. Taken together, these data suggest that POGZ is a critical suppressor of the early stages of the metastatic cascade.
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The ubiquitin proteasome system performs the covalent attachment of lysine 48-linked polyubiquitin chains to substrate proteins, thereby targeting them for degradation, while deubiquitylating enzymes (DUBs) reverse this process. This posttranslational modification regulates key features both of innate and adaptative immunity, including antigen presentation, protein homeostasis and signal transduction. Here we show that loss of one of the most highly expressed DUBs, Otub1, results in changes in murine splenic B cell subsets, leading to a significant increase in marginal zone and transitional B cells and a concomitant decrease in follicular B cells. We demonstrate that Otub1 interacts with the γ-subunit of the heterotrimeric G protein, Gng2, and modulates its ubiquitylation status, thereby controlling Gng2 stability. Proximal mapping of Gng2 revealed an enrichment in partners associated with chemokine signaling, actin cytoskeleton and cell migration. In line with these findings, we show that Otub1-deficient B cells exhibit greater Ca2+ mobilization, F-actin polymerization and chemotactic responsiveness to Cxcl12, Cxcl13 and S1P in vitro, which manifests in vivo as altered localization of B cells within the spleen. Together, our data establishes Otub1 as a novel regulator of G-protein coupled receptor signaling in B cells, regulating their differentiation and positioning in the spleen.
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Quimiotaxis de Leucocito , Enzimas Desubicuitinizantes , Bazo , Ubiquitina , Animales , Ratones , Enzimas Desubicuitinizantes/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Transducción de Señal , Bazo/metabolismo , Ubiquitina/metabolismo , Ubiquitinación , Cisteína Endopeptidasas/metabolismo , Proteínas de Unión al GTP/metabolismo , Linfocitos B/metabolismo , Quimiotaxis de Leucocito/genéticaRESUMEN
Significant efforts have focused on identifying targetable genetic drivers that support the growth of solid tumors and/or increase metastatic ability. During tumor development and progression to metastatic disease, physiological and pharmacological selective pressures influence parallel adaptive strategies within cancer cell sub-populations. Such adaptations allow cancer cells to withstand these stressful microenvironments. This Darwinian model of stress adaptation often prevents durable clinical responses and influences the emergence of aggressive cancers with increased metastatic fitness. However, the mechanisms contributing to such adaptive stress responses are poorly understood. We now demonstrate that the p66ShcA redox protein, itself a ROS inducer, is essential for survival in response to physiological stressors, including anchorage independence and nutrient deprivation, in the context of poor outcome breast cancers. Mechanistically, we show that p66ShcA promotes both glucose and glutamine metabolic reprogramming in breast cancer cells, to increase their capacity to engage catabolic metabolism and support glutathione synthesis. In doing so, chronic p66ShcA exposure contributes to adaptive stress responses, providing breast cancer cells with sufficient ATP and redox balance needed to withstand such transient stressed states. Our studies demonstrate that p66ShcA functionally contributes to the maintenance of aggressive phenotypes and the emergence of metastatic disease by forcing breast tumors to adapt to chronic and moderately elevated levels of oxidative stress.
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Neoplasias de la Mama , Humanos , Femenino , Proteínas Adaptadoras de la Señalización Shc/genética , Proteínas Adaptadoras de la Señalización Shc/metabolismo , Neoplasias de la Mama/metabolismo , Proteína Transformadora 1 que Contiene Dominios de Homología 2 de Src/metabolismo , Estrés Oxidativo/fisiología , Fenotipo , Línea Celular Tumoral , Microambiente TumoralRESUMEN
Genomic rearrangements are a hallmark of most childhood tumors, including medulloblastoma, one of the most common brain tumors in children, but their causes remain largely unknown. Here, we show that PiggyBac transposable element derived 5 (Pgbd5) promotes tumor development in multiple developmentally accurate mouse models of Sonic Hedgehog (SHH) medulloblastoma. Most Pgbd5-deficient mice do not develop tumors, while maintaining normal cerebellar development. Ectopic activation of SHH signaling is sufficient to enforce cerebellar granule cell progenitor-like cell states, which exhibit Pgbd5-dependent expression of distinct DNA repair and neurodevelopmental factors. Mouse medulloblastomas expressing Pgbd5 have increased numbers of somatic structural DNA rearrangements, some of which carry PGBD5-specific sequences at their breakpoints. Similar sequence breakpoints recurrently affect somatic DNA rearrangements of known tumor suppressors and oncogenes in medulloblastomas in 329 children. This identifies PGBD5 as a medulloblastoma mutator and provides a genetic mechanism for the generation of oncogenic DNA rearrangements in childhood cancer.
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Neoplasias Cerebelosas , Meduloblastoma , Humanos , Niño , Animales , Ratones , Meduloblastoma/genética , Transposasas/genética , Transposasas/metabolismo , Proteínas Hedgehog/metabolismo , Factores de Transcripción/genética , Mutagénesis , Neoplasias Cerebelosas/genéticaRESUMEN
The cystic fibrosis transmembrane conductance regulator (CFTR) is expressed in many segments of the mammalian nephron, where it may interact with and modulate the activity of a variety of apical membrane proteins, including the renal outer medullary potassium (ROMK) K(+) channel. However, the expression of CFTR in apical cell membranes or its function as a Cl(-) channel in native renal epithelia has not been demonstrated. Here, we establish that CFTR forms protein kinase A (PKA)-activated Cl(-) channels in the apical membrane of principal cells from the cortical collecting duct obtained from mice. These Cl(-) channels were observed in cell-attached apical patches of principal cells after stimulation by forskolin/3-isobutyl-1-methylxanthine. Quiescent Cl(-) channels were present in patches excised from untreated tubules because they could be activated after exposure to Mg-ATP and the catalytic subunit of PKA. The single-channel conductance, kinetics, and anion selectivity of these Cl(-) channels were the same as those of recombinant mouse CFTR channels expressed in Xenopus laevis oocytes. The CFTR-specific closed-channel blocker CFTR(inh)-172 abolished apical Cl(-) channel activity in excised patches. Moreover, apical Cl(-) channel activity was completely absent in principal cells from transgenic mice expressing the DeltaF508 CFTR mutation but was present and unaltered in ROMK-null mice. We discuss the physiologic implications of open CFTR Cl(-) channels on salt handling by the collecting duct and on the functional CFTR-ROMK interactions in modulating the metabolic ATP-sensing of ROMK.
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Canales de Cloruro/metabolismo , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , AMP Cíclico/metabolismo , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Túbulos Renales Colectores/metabolismo , Animales , Benzoatos/farmacología , Canales de Cloruro/antagonistas & inhibidores , Regulador de Conductancia de Transmembrana de Fibrosis Quística/antagonistas & inhibidores , Regulador de Conductancia de Transmembrana de Fibrosis Quística/deficiencia , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Femenino , Técnicas In Vitro , Corteza Renal/metabolismo , Cinética , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos CFTR , Ratones Noqueados , Ratones Transgénicos , Mutación , Oocitos/metabolismo , Técnicas de Placa-Clamp , Canales de Potasio de Rectificación Interna/deficiencia , Canales de Potasio de Rectificación Interna/genética , Canales de Potasio de Rectificación Interna/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Tiazolidinas/farmacología , Xenopus laevisRESUMEN
Digestion of food and normal salt and water homeostasis in the body require a functional digestive tract. Recently an increasing number of studies have demonstrated a role for the calcium-sensing receptor along the entire gastrointestinal tract and its role in normal gut physiology. Detailed studies have been performed on colonic fluid transport and gastric acid secretion. We have now demonstrated that the receptor can modulate fluid secretion and absorption along the intestine and can thereby be a potent target to prevent secretory diarrhea. Recent studies have demonstrated that organic nutrients such as polyamines and l-amino acids can act as agonists by allosterically modifying the receptor. Thus, the receptor may detect nutrient availability to epithelial cells along the gastrointestinal tract and may be involved in the coordinated rapid turnover of the intestinal epithelium. Furthermore, the receptor has been suggested as a link for the mechanisms leading to calcium uptake by the colon and may thus reduce the risk for colon cancer.
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Calcio/metabolismo , Tracto Gastrointestinal/fisiología , Receptores Sensibles al Calcio/fisiología , Animales , Homeostasis/fisiología , Humanos , Mucosa Intestinal/fisiologíaRESUMEN
A key question in systems biology is how diverse physiologic processes are integrated to produce global homeostasis. Genetic analysis can contribute by identifying genes that perturb this integration. One system orchestrates renal NaCl and K+ flux to achieve homeostasis of blood pressure and serum K+ concentration. Positional cloning implicated the serine-threonine kinase WNK4 in this process; clustered mutations in PRKWNK4, encoding WNK4, cause hypertension and hyperkalemia (pseudohypoaldosteronism type II, PHAII) by altering renal NaCl and K+ handling. Wild-type WNK4 inhibits the renal Na-Cl cotransporter (NCCT); mutations that cause PHAII relieve this inhibition. This explains the hypertension of PHAII but does not account for the hyperkalemia. By expression in Xenopus laevis oocytes, we show that WNK4 also inhibits the renal K+ channel ROMK. This inhibition is independent of WNK4 kinase activity and is mediated by clathrin-dependent endocytosis of ROMK, mechanisms distinct from those that characterize WNK4 inhibition of NCCT. Most notably, the same mutations in PRKWNK4 that relieve NCCT inhibition markedly increase inhibition of ROMK. These findings establish WNK4 as a multifunctional regulator of diverse ion transporters; moreover, they explain the pathophysiology of PHAII. They also identify WNK4 as a molecular switch that can vary the balance between NaCl reabsorption and K+ secretion to maintain integrated homeostasis.
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Riñón/fisiología , Canales de Potasio de Rectificación Interna , Potasio/metabolismo , Proteínas Serina-Treonina Quinasas/fisiología , Receptores de Droga , Cloruro de Sodio/metabolismo , Simportadores , Animales , Proteínas Portadoras/antagonistas & inhibidores , Proteínas Portadoras/metabolismo , Clatrina/metabolismo , Endocitosis , Proteínas Fluorescentes Verdes , Transporte Iónico , Proteínas Luminiscentes/metabolismo , Ratones , Canales de Potasio/metabolismo , Seudohipoaldosteronismo/metabolismo , Ratas , Simportadores del Cloruro de Sodio , Miembro 3 de la Familia de Transportadores de Soluto 12 , Xenopus laevis/metabolismoRESUMEN
(1) Background: Interleukin-6 (IL-6) levels act as an early infection marker preceding C-reactive protein (CRP) elevation. This study seeks to analyze IL-6 behavior in suspected early-onset sepsis (EOS) cases among term newborns, comparing it to that of CRP and evaluating IL-6's diagnostic utility. We also aim to assess the impact of maternal risk factors on EOS in term newborns, quantifying their influence for informed decision making. (2) Methods: The retrospective data analysis included 533 term newborns who were admitted to our hospital because of suspected EOS. IL-6, CRP, and the impact of maternal risk factors were analyzed in the context of EOS using binomial test, Chi-squared test, logistic and linear regression. (3) Results: In the cases of EOS, both IL-6 and CRP were elevated. The increase in CRP can be predicted by the initial increase in IL-6 levels. Among the assessed risk factors, intrapartum maternal fever (adjusted odds ratio 18.1; 95% CI (1.7-4.1)) was identified as the only risk factor significantly associated with EOS. (4) Conclusions: Employing IL-6 as an early infection marker enhanced EOS diagnostic precision due to its detectable early rise. However, caution is required, as elevations in IL-6 and CRP levels do not exclusively indicate EOS. Increased CRP levels in healthy newborns with maternal risk factors may be attributed to dynamics of vaginal labor.
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BACKGROUND: An infection with SARS-CoV-2 can trigger a systemic disorder by pathological autoimmune processes. A certain type of this dysregulation is known as Multisystemic inflammatory syndrome in children (MIS-C). However, similar symptoms may occur and have been described as Multisystemic inflammatory syndrome after SARS-CoV-2 Vaccination (MIS-V) following vaccination against SARS-CoV-2. We report the case of a 12-year-old boy who was identified with MIS-C symptoms without previous SARS-CoV-2 infection after receiving two doses of the Pfizer-BioNTech COVID-19 vaccine approximately one month prior to the onset of symptoms. He showed polyserositis, severe gastrointestinal symptoms and, consequently, a manifestation of a multiorgan failure. IgG antibodies against spike proteins of SARS-CoV-2 were detected, indicating a successful vaccination, while SARS-CoV-2 Nucleocapsid protein antibodies and SARS-CoV-2 PCR were not detected. Several functional, active autoantibodies against G-protein-coupled receptors (GPCR-fAAb), previously associated with Long COVID disease, were detected in a cardiomyocyte bioassay. Immunosuppression with steroids was initiated. Due to side effects, treatment with steroids and later interleukin 1 receptor antagonists had to be terminated. Instead, immunoadsorption was performed and continued with tacrolimus and mycophenolic acid therapy, leading to improvement and discharge after 79 days. GPCR-fAAb decreased during therapy and remained negative after clinical curing and under continued immunosuppressive therapy with tacrolimus and mycophenolic acid. Follow-up of the patient showed him in good condition after one year. CONCLUSIONS: Infection with SARS-CoV-2 shows a broad and severe variety of symptoms, partly due to autoimmune dysregulation, which, in some instances, can lead to multiorgan failure. Despite its rarity, post-vaccine MIS-C-like disease may develop into a serious condition triggered by autoimmune dysregulation. The evidence of circulating GPCR-fAAb and their disappearance after therapy suggests a link of GPCR-fAAb to the clinical manifestations. Thus, we hypothesize a potential role of GPCR-fAAb in pathophysiology and their potential importance for the therapy of MIS-C or MIS-V. However, this observation needs further investigation to prove a causative correlation.
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BACKGROUND: Multisystemic Inflammatory Syndrome in children (MIS-C) is a rare autoimmune disorder occurring after a latency period following acute SARS-CoV-2 infection. The therapeutic regime of MIS-C is adapted to the therapy of the Kawasaki disease, as clinical symptoms are similar. Since the Kawasaki disease can potentially result in severe symptoms, which may even affect long-term health, it is essential to gain further knowledge about MIS-C. Thus, we aimed to investigate the incidence, symptoms, therapeutical procedure and outcome of MIS-C patients in the metropolitan area of Nuremberg-Erlangen during the SARS-CoV2 pandemic. MATERIAL AND METHODS: Retrospective analysis of clinical charts of MIS-C patients was carried out at three children's hospitals covering the medical care of the metropolitan area of Nuremberg-Erlangen in Germany. Demographic characteristics and symptoms at first visit, their clinical course, therapeutic regime and outcome were recorded within the time period January 2021-December 2022. RESULTS: Analysis of 10 patients (5 male, 5 female) with MIS-C resulting in an incidence of 2.14/100.000 children. The median time between COVID-19 infection and admission to hospital was 5 weeks. The median age was 7 years. Symptoms comprised fever (100%), rash (70%), bilateral non-purulent conjunctivitis (70%) and urticaria (20%). At the time of presentation, diagnosis-defining inflammation parameters were increased and the range for C-reactive protein was 4.13 mg/dL to 28 mg/dL, with a median of 24.7 mg/dL. Procalcitonin was initially determined in six patients (1.92 ng/mL to 21.5 ng/mL) with a median value of 5.5 pg/mL. Two patients displayed leukocytosis and two displayed leukopenia. None of the patients presented coronary pathologies. Nine of the ten patients received intravenous immunoglobulin (IVIG) therapy. In addition, patients received intravenous steroids (80%) and acetylsalicylic acid (80%). CONCLUSION: SARS-CoV virus may rarely exert multiorgan manifestations due to hyperinflammatory immunological processes. Within two years of the COVID-19 pandemic, we identified ten patients with COVID-induced MIS-C in the metropolitan area Nuremberg-Erlangen. In the description of the patient collective, we can confirm that MIS-C is distinguished from the Kawasaki disease by the lack of coronary manifestations. Interestingly, although having monitored all pediatric facilities in the investigated area, we find lower incidences of MIS-C compared to findings in the literature. In conclusion, an overestimation of incidences in the upcoming MIS-C during the pandemic needs to be considered.