RESUMEN
Circadian rhythms are nearly ubiquitous throughout nature, suggesting they are critical for survival in diverse environments. Organisms inhabiting largely arrhythmic environments, such as caves, offer a unique opportunity to study the evolution of circadian rhythms in response to changing ecological pressures. Populations of the Mexican tetra, Astyanax mexicanus, have repeatedly invaded caves from surface rivers, where individuals must contend with perpetual darkness, reduced food availability, and limited fluctuations in daily environmental cues. To investigate the molecular basis for evolved changes in circadian rhythms, we investigated rhythmic transcription across multiple independently-evolved cavefish populations. Our findings reveal that evolution in a cave environment has led to the repeated disruption of the endogenous biological clock, and its entrainment by light. The circadian transcriptome shows widespread reductions and losses of rhythmic transcription and changes to the timing of the activation/repression of core-transcriptional clock. In addition to dysregulation of the core clock, we find that rhythmic transcription of the melatonin regulator aanat2 and melatonin rhythms are disrupted in cavefish under darkness. Mutants of aanat2 and core clock gene rorca disrupt diurnal regulation of sleep in A. mexicanus, phenocopying circadian modulation of sleep and activity phenotypes of cave populations. Together, these findings reveal multiple independent mechanisms for loss of circadian rhythms in cavefish populations and provide a platform for studying how evolved changes in the biological clock can contribute to variation in sleep and circadian behavior.
Asunto(s)
Evolución Biológica , Characidae/fisiología , Relojes Circadianos/genética , Proteínas de Peces/genética , Animales , Encéfalo/fisiología , Cuevas , Characidae/genética , Relojes Circadianos/fisiología , Evolución Molecular , Regulación de la Expresión Génica , Genética de Población , Hibridación Fluorescente in Situ , Hígado/fisiología , Melatonina/metabolismo , Mutación , Sueño/genética , Sueño/fisiologíaRESUMEN
Cerebral palsy (CP) neurologic care and research efforts typically focus on children. However, most people with CP are adults. Adults with CP are at increased risk of new neurologic conditions, such as stroke and myelopathy, that require ongoing neurologic surveillance to distinguish them from baseline motor impairments. Neurologic factors could also contribute to the motor function decline, chronic pain, and chronic fatigue that are commonly experienced by adults with CP. Based on a systematic literature review, we suggest (1) guidelines for neurologic surveillance and neurologist referral and (2) clinical research questions regarding the evolving neurologic risks for adults with CP. ANN NEUROL 2021;89:860-871.
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Parálisis Cerebral/terapia , Neurología , Atención al Paciente , Adulto , Niño , Humanos , Enfermedades del Sistema Nervioso/complicaciones , Enfermedades del Sistema Nervioso/terapiaRESUMEN
AIM: To determine the features cited by motor phenotyping experts when identifying dystonia in people with cerebral palsy (CP). METHOD: Dystonia identification in CP, particularly when comorbid with spasticity, can be difficult. The dystonia diagnostic criterion standard remains subjective visual identification by expert consensus. For this qualitative study, we conducted an inductive thematic analysis of consensus-building discussions between three pediatric movement disorder physicians as they identified the presence or absence of dystonia in gait videos of 40 participants with spastic CP and periventricular leukomalacia. RESULTS: Unanimous consensus about the presence or absence of dystonia was achieved for 34 out of 40 videos. Two main themes were present during consensus-building discussions as videos were evaluated for dystonia: (1) unilateral leg or foot adduction that was variable over time, and (2) difficulty in identifying dystonia. Codes contributing to the first theme were more likely to be cited by a discussant when they felt dystonia was present (as opposed to absent) in a video (χ2 test, p=0.004). DISCUSSION: These results describe the gait features cited by experts during consensus-building discussion as they identify dystonia in ambulatory people with CP. Qualitative thematic analysis of these discussions could help codify the subjective process of dystonia diagnosis.
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Parálisis Cerebral/fisiopatología , Distonía/diagnóstico , Marcha/fisiología , Leucomalacia Periventricular/fisiopatología , Espasticidad Muscular/fisiopatología , Adolescente , Parálisis Cerebral/complicaciones , Niño , Preescolar , Distonía/etiología , Distonía/fisiopatología , Femenino , Humanos , Leucomalacia Periventricular/complicaciones , Masculino , Espasticidad Muscular/complicaciones , Adulto JovenRESUMEN
Control of neuronal precursor cell proliferation is essential for normal brain development, and deregulation of this fundamental developmental event contributes to brain diseases. Typically, neuronal precursor cell proliferation extends over long periods of time during brain development. However, how neuronal precursor proliferation is regulated in a temporally specific manner remains to be elucidated. Here, we report that conditional KO of the transcriptional regulator SnoN in cerebellar granule neuron precursors robustly inhibits the proliferation of these cells and promotes their cell cycle exit at later stages of cerebellar development in the postnatal male and female mouse brain. In laser capture microdissection followed by RNA-Seq, designed to profile gene expression specifically in the external granule layer of the cerebellum, we find that SnoN promotes the expression of cell proliferation genes and concomitantly represses differentiation genes in granule neuron precursors in vivo Remarkably, bioinformatics analyses reveal that SnoN-regulated genes contain binding sites for the transcription factors N-myc and Pax6, which promote the proliferation and differentiation of granule neuron precursors, respectively. Accordingly, we uncover novel physical interactions of SnoN with N-myc and Pax6 in cells. In behavior analyses, conditional KO of SnoN impairs cerebellar-dependent learning in a delayed eye-blink conditioning paradigm, suggesting that SnoN-regulation of granule neuron precursor proliferation bears functional consequences at the organismal level. Our findings define a novel function and mechanism for the major transcriptional regulator SnoN in the control of granule neuron precursor proliferation in the mammalian brain.SIGNIFICANCE STATEMENT This study reports the discovery that the transcriptional regulator SnoN plays a crucial role in the proliferation of cerebellar granule neuron precursors in the postnatal mouse brain. Conditional KO of SnoN in granule neuron precursors robustly inhibits the proliferation of these cells and promotes their cycle exit specifically at later stages of cerebellar development, with biological consequences of impaired cerebellar-dependent learning. Genomics and bioinformatics analyses reveal that SnoN promotes the expression of cell proliferation genes and concomitantly represses cell differentiation genes in vivo Although SnoN has been implicated in distinct aspects of the development of postmitotic neurons, this study identifies a novel function for SnoN in neuronal precursors in the mammalian brain.
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Encéfalo/citología , Proliferación Celular , Cerebelo/fisiología , Células-Madre Neurales/fisiología , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/fisiología , Animales , Conducta Animal , Parpadeo/fisiología , Encéfalo/crecimiento & desarrollo , Diferenciación Celular/genética , Cerebelo/citología , Biología Computacional , Gránulos Citoplasmáticos/fisiología , Femenino , Regulación de la Expresión Génica/genética , Regulación de la Expresión Génica/fisiología , Genes myc/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Factor de Transcripción PAX6/genética , Factor de Transcripción PAX6/fisiologíaRESUMEN
Interferon inducible transmembrane proteins (IFITMs) are broad-spectrum antiviral factors. In cell culture the entry of many enveloped viruses, including orthomyxo-, flavi-, and filoviruses, is inhibited by IFITMs, though the mechanism(s) involved remain unclear and may vary between viruses. We demonstrate that Sindbis and Semliki Forest virus (SFV), which both use endocytosis and acid-induced membrane fusion in early endosomes to infect cells, are restricted by the early endosomal IFITM3. The late endosomal IFITM2 is less restrictive and the plasma membrane IFITM1 does not inhibit normal infection by either virus. IFITM3 inhibits release of the SFV capsid into the cytosol, without inhibiting binding, internalization, trafficking to endosomes or low pH-induced conformational changes in the envelope glycoprotein. Infection by SFV fusion at the cell surface was inhibited by IFITM1, but was equally inhibited by IFITM3. Furthermore, an IFITM3 mutant (Y20A) that is localized to the plasma membrane inhibited infection by cell surface fusion more potently than IFITM1. Together, these results indicate that IFITMs, in particular IFITM3, can restrict alphavirus infection by inhibiting viral fusion with cellular membranes. That IFITM3 can restrict SFV infection by fusion at the cell surface equivalently to IFITM1 suggests that IFITM3 has greater antiviral potency against SFV.
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Antígenos de Diferenciación/metabolismo , Endosomas/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de Unión al ARN/metabolismo , Virus de los Bosques Semliki/fisiología , Virus Sindbis/fisiología , Células A549 , Infecciones por Alphavirus/metabolismo , Infecciones por Alphavirus/virología , Antígenos de Diferenciación/genética , Endocitosis/fisiología , Endosomas/virología , Humanos , Proteínas de la Membrana/genética , Proteínas de Unión al ARN/genética , Internalización del VirusRESUMEN
Contaminated water is a major risk factor associated with the transmission of Salmonella enterica serovar Typhi (S. Typhi), the aetiological agent of human typhoid. However, little is known about how this pathogen adapts to living in the aqueous environment. We used transcriptome analysis (RNA-seq) and transposon mutagenesis (TraDIS) to characterize these adaptive changes and identify multiple genes that contribute to survival. Over half of the genes in the S. Typhi genome altered expression level within the first 24 h following transfer from broth culture to water, although relatively few did so in the first 30 min. Genes linked to central metabolism, stress associated with arrested proton motive force and respiratory chain factors changed expression levels. Additionally, motility and chemotaxis genes increased expression, consistent with a scavenging lifestyle. The viaB-associated gene tviC encoding a glcNAc epimerase that is required for Vi polysaccharide biosynthesis was, along with several other genes, shown to contribute to survival in water. Thus, we define regulatory adaptation operating in S. Typhi that facilitates survival in water.
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Agua Dulce/microbiología , Viabilidad Microbiana , Salmonella typhi/crecimiento & desarrollo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica , Humanos , Mutagénesis , Plásmidos/genética , Plásmidos/metabolismo , Polisacáridos Bacterianos/biosíntesis , Salmonella typhi/genética , Salmonella typhi/metabolismo , Fiebre Tifoidea/microbiologíaRESUMEN
The 2009 H1N1 influenza pandemic showed the speed with which a novel respiratory virus can spread and the ability of a generally mild infection to induce severe morbidity and mortality in a subset of the population. Recent in vitro studies show that the interferon-inducible transmembrane (IFITM) protein family members potently restrict the replication of multiple pathogenic viruses. Both the magnitude and breadth of the IFITM proteins' in vitro effects suggest that they are critical for intrinsic resistance to such viruses, including influenza viruses. Using a knockout mouse model, we now test this hypothesis directly and find that IFITM3 is essential for defending the host against influenza A virus in vivo. Mice lacking Ifitm3 display fulminant viral pneumonia when challenged with a normally low-pathogenicity influenza virus, mirroring the destruction inflicted by the highly pathogenic 1918 'Spanish' influenza. Similar increased viral replication is seen in vitro, with protection rescued by the re-introduction of Ifitm3. To test the role of IFITM3 in human influenza virus infection, we assessed the IFITM3 alleles of individuals hospitalized with seasonal or pandemic influenza H1N1/09 viruses. We find that a statistically significant number of hospitalized subjects show enrichment for a minor IFITM3 allele (SNP rs12252-C) that alters a splice acceptor site, and functional assays show the minor CC genotype IFITM3 has reduced influenza virus restriction in vitro. Together these data reveal that the action of a single intrinsic immune effector, IFITM3, profoundly alters the course of influenza virus infection in mouse and humans.
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Virus de la Influenza A/patogenicidad , Proteínas de la Membrana/metabolismo , Infecciones por Orthomyxoviridae/mortalidad , Proteínas de Unión al ARN/metabolismo , Alelos , Secuencia de Aminoácidos , Animales , Citocinas/inmunología , Inglaterra/epidemiología , Eliminación de Gen , Humanos , Subtipo H1N1 del Virus de la Influenza A/clasificación , Subtipo H1N1 del Virus de la Influenza A/crecimiento & desarrollo , Subtipo H1N1 del Virus de la Influenza A/patogenicidad , Subtipo H3N2 del Virus de la Influenza A/clasificación , Subtipo H3N2 del Virus de la Influenza A/crecimiento & desarrollo , Subtipo H3N2 del Virus de la Influenza A/patogenicidad , Virus de la Influenza A/clasificación , Virus de la Influenza A/crecimiento & desarrollo , Virus de la Influenza B/clasificación , Virus de la Influenza B/crecimiento & desarrollo , Virus de la Influenza B/patogenicidad , Gripe Humana/complicaciones , Gripe Humana/epidemiología , Gripe Humana/mortalidad , Gripe Humana/virología , Leucocitos/inmunología , Pulmón/patología , Pulmón/virología , Proteínas de la Membrana/química , Proteínas de la Membrana/deficiencia , Proteínas de la Membrana/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Datos de Secuencia Molecular , Infecciones por Orthomyxoviridae/complicaciones , Infecciones por Orthomyxoviridae/patología , Neumonía Viral/etiología , Neumonía Viral/patología , Neumonía Viral/prevención & control , Polimorfismo de Nucleótido Simple/genética , Proteínas de Unión al ARN/química , Proteínas de Unión al ARN/genética , Escocia/epidemiología , Replicación ViralRESUMEN
BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) is an important global public health threat, but accurate estimates of MDR-TB burden among children are lacking. METHODS: We analyzed demographic, clinical, and laboratory data for newly diagnosed pediatric (age <15 years) TB cases reported to the US National TB Surveillance System during 1993-2014. MDR-TB was defined as culture-confirmed TB disease with resistance to at least isoniazid and rifampicin. To ascertain potential underestimation of pediatric MDR-TB, we surveyed high-burden states for clinically diagnosed cases treated for MDR-TB. RESULTS: Of 20789 pediatric TB cases, 5162 (24.8%) had bacteriologically confirmed TB. Among 4826 (93.5%) with drug susceptibility testing, 82 (1.7%) had MDR-TB. Most pediatric MDR-TB cases were female (n = 51 [62%]), median age was 5 years (interquartile range, 1-12 years), one-third were Hispanic (n = 28 [34%]), and two-thirds (n = 55 [67%]) were born in the United States. Most cases had additional resistance to ≥1 other first-line drug (n = 66 [81%]) and one-third had resistance to ≥1 second-line drug (24/73 tested). Of 77 who started treatment prior to 2013, 66 (86%) completed treatment and 4 (5%) died. Among the 4 high-TB-burden states/jurisdictions surveyed, there was 42%-55% underestimation of pediatric MDR-TB cases when using only culture-confirmed case definitions. CONCLUSIONS: Only one-quarter of pediatric TB cases had culture-confirmed TB, likely resulting in underestimation of true pediatric MDR-TB burden in the United States using strictly bacteriologic criteria. Better estimates of pediatric MDR-TB burden in the United States are needed and should include clinical diagnoses based on epidemiologic criteria.
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Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Adolescente , Antituberculosos/uso terapéutico , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Mycobacterium tuberculosis , Estudios Retrospectivos , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/microbiología , Estados Unidos/epidemiologíaRESUMEN
BACKGROUND: Resistance to second-line drugs develops during treatment of multidrug-resistant (MDR) tuberculosis, but the impact on treatment outcome has not been determined. METHODS: Patients with MDR tuberculosis starting second-line drug treatment were enrolled in a prospective cohort study. Sputum cultures were analyzed at a central reference laboratory. We compared subjects with successful and poor treatment outcomes in terms of (1) initial and acquired resistance to fluoroquinolones and second-line injectable drugs (SLIs) and (2) treatment regimens. RESULTS: Of 1244 patients with MDR tuberculosis, 973 (78.2%) had known outcomes and 232 (18.6%) were lost to follow-up. Among those with known outcomes, treatment succeeded in 85.8% with plain MDR tuberculosis, 69.7% with initial resistance to either a fluoroquinolone or an SLI, 37.5% with acquired resistance to a fluoroquinolone or SLI, 29.3% with initial and 13.0% with acquired extensively drug-resistant tuberculosis (P < .001 for trend). In contrast, among those with known outcomes, treatment success increased stepwise from 41.6% to 92.3% as the number of drugs proven effective increased from ≤1 to ≥5 (P < .001 for trend), while acquired drug resistance decreased from 12% to 16% range, depending on the drug, down to 0%-2% (P < .001 for trend). In multivariable analysis, the adjusted odds of treatment success decreased 0.62-fold (95% confidence interval, .56-.69) for each increment in drug resistance and increased 2.1-fold (1.40-3.18) for each additional effective drug, controlling for differences between programs and patients. Specific treatment, patient, and program variables were also associated with treatment outcome. CONCLUSIONS: Increasing drug resistance was associated in a logical stepwise manner with poor treatment outcomes. Acquired resistance was worse than initial resistance to the same drugs. Increasing numbers of effective drugs, specific drugs, and specific program characteristics were associated with better outcomes and less acquired resistance.
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Antituberculosos/uso terapéutico , Mycobacterium tuberculosis/efectos de los fármacos , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Adolescente , Adulto , Anciano , Farmacorresistencia Bacteriana Múltiple , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis/aislamiento & purificación , Estudios Prospectivos , Esputo/microbiología , Resultado del Tratamiento , Adulto JovenRESUMEN
Acquired resistance to antituberculosis drugs decreases effective treatment options and the likelihood of treatment success. We identified risk factors for acquisition of drug resistance during treatment for multidrug-resistant tuberculosis (MDR TB) and evaluated the effect on treatment outcomes. Data were collected prospectively from adults from Arkhangelsk Oblast, Russia, who had pulmonary MDR TB during 2005-2008. Acquisition of resistance to capreomycin and of extensively drug-resistant TB were more likely among patients who received <3 effective drugs than among patients who received >3 effective drugs (9.4% vs. 0% and 8.6% vs. 0.8%, respectively). Poor outcomes were more likely among patients with acquired capreomycin resistance (100% vs. 25.9%), acquired ofloxacin resistance (83.6% vs. 22.7%), or acquired extensive drug resistance (100% vs. 24.4%). To prevent acquired drug resistance and poor outcomes, baseline susceptibility to first- and second-line drugs should be determined quickly, and treatment should be adjusted to contain >3 effective drugs.
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Antituberculosos/farmacología , Farmacorresistencia Bacteriana Múltiple , Mycobacterium tuberculosis/efectos de los fármacos , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Tuberculosis Resistente a Múltiples Medicamentos/microbiología , Adulto , Antituberculosos/uso terapéutico , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Federación de Rusia/epidemiología , Resultado del Tratamiento , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Adulto JovenRESUMEN
IFN-induced transmembrane protein 3 (IFITM3) is a restriction factor that blocks cytosolic entry of numerous viruses that utilize acidic endosomal entry pathways. In humans and mice, IFITM3 limits influenza-induced morbidity and mortality. Although many IFITM3-sensitive viruses are zoonotic, whether IFITMs function as antiviral restriction factors in mammalian species other than humans and mice is unknown. Here, IFITM3 orthologues in the microbat (Myotis myotis) and pig (Sus scrofa domesticus) were identified using rapid amplification of cDNA ends. Amino acid residues known to be important for IFITM3 function were conserved in the pig and microbat orthologues. Ectopically expressed pig and microbat IFITM3 co-localized with transferrin (early endosomes) and CD63 (late endosomes/multivesicular bodies). Pig and microbat IFITM3 restricted cell entry mediated by multiple influenza haemagglutinin subtypes and lyssavirus glycoproteins. Expression of pig or microbat IFITM3 in A549 cells reduced influenza virus yields and nucleoprotein expression. Conversely, small interfering RNA knockdown of IFITM3 in pig NPTr cells and primary microbat cells enhanced virus replication, demonstrating that these genes are functional in their species of origin at endogenous levels. In summary, we showed that IFITMs function as potent broad-spectrum antiviral effectors in two mammals - pigs and bats - identified as major reservoirs for emerging viruses.
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Interferones/inmunología , Lyssavirus/inmunología , Proteínas de la Membrana/metabolismo , Orthomyxoviridae/inmunología , Proteínas de Unión al ARN/metabolismo , Internalización del Virus , Animales , Quirópteros , Secuencia Conservada , Lyssavirus/fisiología , Proteínas de la Membrana/genética , Orthomyxoviridae/fisiología , Proteínas de Unión al ARN/genética , Homología de Secuencia de Aminoácido , PorcinosRESUMEN
Green fluorescent protein (GFP) animal models have become increasingly popular due to their potential to enhance in vivo imaging and their application to many fields of study. We have developed a technique to observe host tissue integration into scaffolds using GFP expressing swine and fluorescence imaging. Current fluorescence imaging preparation methods cannot be translated to a full GFP animal model due to several challenges and limitations that are investigated here. We have implanted tissue scaffolds into GFP expressing swine and have prepared explanted scaffolds for fluorescence imaging using four different methods including formalin fixation and paraffin embedding, vapor fixation, freshly prepared paraformaldehyde fixation, and fresh frozen tissue. Explanted scaffolds and tissue were imaged using confocal microscopy with spectral separation to evaluate the GFP animal model for visualization of host tissue integration into explanted scaffolds. All methods except fresh frozen tissue induced autofluorescence of the scaffold, preventing visualization of detail between host tissue and scaffold fibers. Fresh frozen tissue preparation allowed for the most reliable visualization of fluorescent host tissue integration into non-fluorescent scaffolds. It was concluded that fresh frozen tissue preparation is the best method for fluorescence imaging preparation when using scaffolds implanted into GFP whole animal models.
Asunto(s)
Modelos Animales , Andamios del Tejido , Animales , Proteínas Fluorescentes Verdes/genética , Microscopía Confocal , PorcinosRESUMEN
BACKGROUND: Increasing access to drugs for the treatment of multidrug-resistant (MDR) tuberculosis is crucial but could lead to increasing resistance to these same drugs. In 2000, the international Green Light Committee (GLC) initiative began to increase access while attempting to prevent acquired resistance. METHODS: To assess the GLC's impact, we followed adults with pulmonary MDR tuberculosis from the start to the end of treatment with monthly sputum cultures, drug susceptibility testing, and genotyping. We compared the frequency and predictors of acquired resistance to second-line drugs (SLDs) in 9 countries that volunteered to participate, 5 countries that met GLC criteria, and 4 countries that did not apply to the GLC. RESULTS: In total, 832 subjects were enrolled. Of those without baseline resistance to specific SLDs, 68 (8.9%) acquired extensively drug-resistant (XDR) tuberculosis, 79 (11.2%) acquired fluoroquinolone (FQ) resistance, and 56 (7.8%) acquired resistance to second-line injectable drugs (SLIs). The relative risk (95% confidence interval [CI]) of acquired resistance was lower at GLC-approved sites: 0.27 (.16-.47) for XDR tuberculosis, 0.28 (.17-.45) for FQ, and 0.15 (.06-.39) to 0.60 (.34-1.05) for 3 different SLIs. The risk increased as the number of potentially effective drugs decreased. Controlling for baseline drug resistance and differences between sites, the odds ratios (95% CIs) were 0.21 (.07-.62) for acquired XDR tuberculosis and 0.23 (.09-.59) for acquired FQ resistance. CONCLUSIONS: Treatment of MDR tuberculosis involves substantial risk of acquired resistance to SLDs, increasing as baseline drug resistance increases. The risk was significantly lower in programs documented by the GLC to meet specific standards.
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Antituberculosos/uso terapéutico , Farmacorresistencia Bacteriana Múltiple , Mycobacterium tuberculosis/efectos de los fármacos , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/microbiología , Tuberculosis Pulmonar/tratamiento farmacológico , Tuberculosis Pulmonar/microbiología , Adolescente , Adulto , Anciano , Estudios de Cohortes , Femenino , Técnicas de Genotipaje , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Mycobacterium tuberculosis/aislamiento & purificación , Estudios Prospectivos , Selección Genética , Esputo/microbiología , Adulto JovenRESUMEN
The interferon-induced transmembrane protein 3 (IFITM3) gene is an interferon-stimulated gene that inhibits the replication of multiple pathogenic viruses in vitro and in vivo. IFITM3 is a member of a large protein superfamily, whose members share a functionally undefined area of high amino acid conservation, the CD225 domain. We performed mutational analyses of IFITM3 and identified multiple residues within the CD225 domain, consisting of the first intramembrane domain (intramembrane domain 1 [IM1]) and a conserved intracellular loop (CIL), that are required for restriction of both influenza A virus (IAV) and dengue virus (DENV) infection in vitro. Two phenylalanines within IM1 (F75 and F78) also mediate a physical association between IFITM proteins, and the loss of this interaction decreases IFITM3-mediated restriction. By extension, similar IM1-mediated associations may contribute to the functions of additional members of the CD225 domain family. IFITM3's distal N-terminal domain is also needed for full antiviral activity, including a tyrosine (Y20), whose alteration results in mislocalization of a portion of IFITM3 to the cell periphery and surface. Comparative analyses demonstrate that similar molecular determinants are needed for IFITM3's restriction of both IAV and DENV. However, a portion of the CIL including Y99 and R87 is preferentially needed for inhibition of the orthomyxovirus. Several IFITM3 proteins engineered with rare single-nucleotide polymorphisms demonstrated reduced expression or mislocalization, and these events were associated with enhanced viral replication in vitro, suggesting that possessing such alleles may impact an individual's risk for viral infection. On the basis of this and other data, we propose a model for IFITM3-mediated restriction.
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Virus del Dengue/fisiología , Virus de la Influenza A/fisiología , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Replicación Viral/fisiología , Secuencia de Aminoácidos , Animales , Técnicas de Cultivo de Célula , Clonación Molecular , Secuencia Conservada/genética , Análisis Mutacional de ADN , ADN Complementario/genética , Perros , Células HEK293 , Células HeLa , Humanos , Immunoblotting , Inmunoprecipitación , Células de Riñón Canino Madin Darby , Espectrometría de Masas , Microscopía Confocal , Modelos Biológicos , Datos de Secuencia Molecular , Polimorfismo de Nucleótido Simple/genética , Estructura Terciaria de Proteína/genética , Replicación Viral/genéticaRESUMEN
Pilar cysts are common benign cysts of follicular origin that typically arise in areas of skin containing dense hair follicles such as the scalp. Here we describe a unique case of a young woman who was found to have a pilar cyst on the dorsum of her hand, a rather atypical location given the relative lack of pilosebaceous units. This case illustrates the variability in pilar cyst presentation and the importance of considering a pilar cyst in the differential diagnosis of a patient presenting with a tumor of the dorsal hand.
RESUMEN
Karyotypes, composed of chromosomes, must be accurately partitioned by the mitotic spindle for optimal cell health. However, it is unknown how underlying characteristics of karyotypes, such as chromosome number and size, govern the scaling of the mitotic spindle to ensure accurate chromosome segregation and cell proliferation. We utilize budding yeast strains engineered with fewer chromosomes, including just two "mega chromosomes," to study how spindle size and function are responsive to, and scaled by, karyotype. We determined that deletion and overexpression of spindle-related genes are detrimental to the growth of strains with two chromosomes, suggesting that mega chromosomes exert altered demands on the spindle. Using confocal microscopy, we demonstrate that cells with fewer but longer chromosomes have smaller spindle pole bodies, fewer microtubules, and longer spindles. Moreover, using electron tomography and confocal imaging, we observe elongated, bent anaphase spindles with fewer core microtubules in strains with mega chromosomes. Cells harboring mega chromosomes grow more slowly, are delayed in mitosis, and a subset struggle to complete chromosome segregation. We propose that the karyotype of the cell dictates the microtubule number, type, spindle pole body size, and spindle length, subsequently influencing the dynamics of mitosis, such as the rate of spindle elongation and the velocity of pole separation. Taken together, our results suggest that mitotic spindles are highly plastic ultrastructures that can accommodate and adjust to a variety of karyotypes, even within a species.
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Saccharomyces cerevisiae , Huso Acromático , Huso Acromático/metabolismo , Saccharomyces cerevisiae/genética , Microtúbulos/metabolismo , Segregación Cromosómica , Mitosis , Cromosomas Fúngicos/genética , CariotipoRESUMEN
Previous studies of hematopoietic stem cells (HSCs) primarily focused on single cell-based niche models, yielding fruitful but conflicting findings 1-5 . Here we report our investigation on the fetal liver (FL) as the primary fetal hematopoietic site using spatial transcriptomics. Our study reveals two distinct niches: the portal-vessel (PV) niche and the sinusoidal niche. The PV niche, composing N-cadherin (N-cad) Hi Pdgfrα + mesenchymal stromal cells (MSCs), endothelial cells (ECs), and N-cad Lo Albumin + hepatoblasts, maintains quiescent and multipotential FL-HSCs. Conversely, the sinusoidal niche, comprising ECs, hepatoblasts and hepatocytes, as well as potential macrophages and megakaryocytes, supports proliferative FL-HSCs biased towards myeloid lineages. Unlike prior reports on the role of Cxcl12, with its depletion from vessel-associated stromal cells leading to 80% of HSCs' reduction in the adult bone marrow (BM) 6,7 , depletion of Cxcl12 via Cdh2 CreERT (encoding N-cad) induces altered localization of HSCs from the PV to the sinusoidal niches, resulting in an increase of HSC number but with myeloid-bias. Similarly, we discovered that adult BM encompasses two niches within different zones, each composed of multi-cellular components: trabecular bone area (TBA, or metaphysis) supporting deep-quiescent HSCs, and central marrow (CM, or diaphysis) fostering heterogenous proliferative HSCs. This study transforms our understanding of niches by shifting from single cell-based to multicellular components within distinct zones, illuminating the intricate regulation of HSCs tailored to their different cycling states.
RESUMEN
BACKGROUND: Accumulating preclinical and preliminary translational evidence shows that the hypothalamic peptide oxytocin reduces food intake, increases energy expenditure, and promotes weight loss. It is currently unknown whether oxytocin administration is effective in treating human obesity. METHODS: In this randomized, double-blind, placebo-controlled trial, we randomly assigned adults with obesity 1:1 (stratified by sex and obesity class) to receive intranasal oxytocin (24 IU) or placebo four times daily for 8 weeks. The primary end point was change in body weight (kg) from baseline to week 8. Key secondary end points included change in body composition (total fat mass [g], abdominal visceral adipose tissue [cm2], and liver fat fraction [proportion; range, 0 to 1; higher values indicate a higher proportion of fat]), and resting energy expenditure (kcal/day; adjusted for lean mass) from baseline to week 8 and caloric intake (kcal) at an experimental test meal from baseline to week 6. RESULTS: Sixty-one participants (54% women; mean age ± standard deviation, 33.6 ± 6.2 years; body-mass index [the weight in kilograms divided by the square of the height in meters], 36.9 ± 4.9) were randomly assigned. There was no difference in body weight change from baseline to week 8 between oxytocin and placebo groups (0.20 vs. 0.26 kg; P=0.934). Oxytocin (vs. placebo) was not associated with beneficial effects on body composition or resting energy expenditure from baseline to week 8 (total fat: difference [95% confidence interval], 196.0 g [-1036 to 1428]; visceral fat: 3.1 cm2 [-11.0 to 17.2]; liver fat: -0.01 [-0.03 to 0.01]; resting energy expenditure: -64.0 kcal/day [-129.3 to 1.4]). Oxytocin compared with placebo was associated with reduced caloric intake at the test meal (-31.4 vs. 120.6 kcal; difference [95% confidence interval], -152.0 kcal [-302.3 to -1.7]). There were no serious adverse events. Incidence and severity of adverse events did not differ between groups. CONCLUSIONS: In this randomized, placebo-controlled trial in adults with obesity, intranasal oxytocin administered four times daily for 8 weeks did not reduce body weight. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; ClinicalTrials.gov number, NCT03043053.).
Asunto(s)
Administración Intranasal , Obesidad , Oxitocina , Humanos , Oxitocina/administración & dosificación , Oxitocina/farmacología , Oxitocina/efectos adversos , Femenino , Masculino , Adulto , Obesidad/tratamiento farmacológico , Método Doble Ciego , Metabolismo Energético/efectos de los fármacos , Composición Corporal/efectos de los fármacos , Ingestión de Energía/efectos de los fármacos , Pérdida de Peso/efectos de los fármacosRESUMEN
The effects of free radical inhibitor on the electron beam crosslinking and thermal processing stabilization of novel radiation crosslinkable polyurethane shape memory polymers (SMPs) blended with acrylic radiation sensitizers have been determined. The SMPs in this study possess novel processing capabilities-that is, the ability to be melt processed into complex geometries as thermoplastics and crosslinked in a secondary step using electron beam irradiation. To increase susceptibility to radiation crosslinking, the radiation sensitizer pentaerythritol triacrylate (PETA) was solution blended with thermoplastic polyurethane SMPs made from 2-butene-1,4-diol and trimethylhexamethylene diisocyanate (TMHDI). Because thermoplastic melt processing methods such as injection molding are often carried out at elevated temperatures, sensitizer thermal instability is a major processing concern. Free radical inhibitor can be added to provide thermal stabilization; however, inhibitor can also undesirably inhibit radiation crosslinking. In this study, we quantified both the thermal stabilization and radiation crosslinking inhibition effects of the inhibitor 1,4-benzoquinone (BQ) on polyurethane SMPs blended with PETA. Sol/gel analysis of irradiated samples showed that the inhibitor had little to no inverse effects on gel fraction at concentrations of 0-10,000 ppm, and dynamic mechanical analysis showed only a slight negative correlation between BQ composition and rubbery modulus. The 1,4-benzoquinone was also highly effective in thermally stabilizing the acrylic sensitizers. The polymer blends could be heated to 150°C for up to five hours or to 125°C for up to 24 hours if stabilized with 10,000 ppm BQ and could also be heated to 125°C for up to 5 hours if stabilized with 1000 ppm BQ without sensitizer reaction occurring. We believe this study provides significant insight into methods for manipulation of the competing mechanisms of radiation crosslinking and thermal stabilization of radiation sensitizers, thereby facilitating further development of radiation crosslinkable thermoplastic SMPs.