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VPS4B (vacuolar protein sorting 4B), a member of the ATPase associated with diverse cellular activities (AAA) protein family, is a component of the endosomal sorting complexes required for transport machinery which regulates the internalization and lysosomal degradation of membrane proteins. We previously reported that VPS4B is one of the pathogenic genes related to dentin dysplasia type I, although its function was largely unknown. To investigate the role of VPS4B in tooth development, we deleted the Vps4b gene in mice. We found that heterozygous knockout mice (Vps4b+/- ) developed normally and were fertile. However, homozygous deletion of the Vps4b gene resulted in early embryonic lethality of Vps4b-/- mice at approximately embryonic day 9.5 (E9.5). To investigate the underlying molecular mechanisms, we examined the molecular functions of VPS4B in vivo and in vitro. Cell experiments showed that VPS4B influenced the proliferation, apoptosis, and cell cycle of transfected human neuroblastoma cells (IMR-32 cells) with over-expression or knockdown of VPS4B. Moreover, qRT-PCR detection showed that the mRNA expression levels of apoptosis-, cell cycle-, and endocytosis-related genes was significantly down or up-regulated in RNA interference-mediated knockdown of VPS4B in IMR-32 cells and Vps4b+/- E12.5 embryos. We accordingly speculated that signal transduction disorders of cell endocytosis are a contributing factor to the prenatal lethality of Vps4b-/- mice.
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ATPasas Asociadas con Actividades Celulares Diversas/genética , Displasia de la Dentina/genética , Endocitosis , Complejos de Clasificación Endosomal Requeridos para el Transporte/genética , Transducción de Señal , ATPasas Asociadas con Actividades Celulares Diversas/deficiencia , Animales , Apoptosis , Línea Celular Tumoral , Complejos de Clasificación Endosomal Requeridos para el Transporte/deficiencia , Humanos , Ratones , Ratones Endogámicos C57BLRESUMEN
Not available.
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Talasemia , Talasemia alfa , Quimerismo , Homocigoto , Humanos , Talasemia alfa/genéticaRESUMEN
Charcot-Marie-Tooth disease is a hereditary motor and sensory neuropathy exhibiting great clinical and genetic heterogeneity. Here, the identification of two heterozygous missense mutations in the C1orf194 gene at 1p21.2-p13.2 with Charcot-Marie-Tooth disease are reported. Specifically, the p.I122N mutation was the cause of an intermediate form of Charcot-Marie-Tooth disease, and the p.K28I missense mutation predominately led to the demyelinating form. Functional studies demonstrated that the p.K28I variant significantly reduced expression of the protein, but the p.I122N variant increased. In addition, the p.I122N mutant protein exhibited the aggregation in neuroblastoma cell lines and the patient's peroneal nerve. Either gain-of-function or partial loss-of-function mutations to C1ORF194 can specify different causal mechanisms responsible for Charcot-Marie-Tooth disease with a wide range of clinical severity. Moreover, a knock-in mouse model confirmed that the C1orf194 missense mutation p.I121N led to impairments in motor and neuromuscular functions, and aberrant myelination and axonal phenotypes. The loss of normal C1ORF194 protein altered intracellular Ca2+ homeostasis and upregulated Ca2+ handling regulatory proteins. These findings describe a novel protein with vital functions in peripheral nervous systems and broaden the causes of Charcot-Marie-Tooth disease, which open new avenues for the diagnosis and treatment of related neuropathies.
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Enfermedad de Charcot-Marie-Tooth/genética , Animales , Calcio/metabolismo , Técnicas de Sustitución del Gen , Humanos , Ratones , Ratones Transgénicos , Mutación Missense , LinajeRESUMEN
Next generation sequencing identified a de novo, 204 kb, tandem duplication (αααα204 ) in the α-globin gene cluster of a Chinese thalassaemia intermedia patient. Haplotype analysis showed that the duplicated chromosome was of paternal origin. Molecular analysis of genomic DNA from the patient's lymphocytes, hair follicles, buccal mucosa cells, his father's lymphocytes and sperm cells excluded the possibility of somatic or germinal mosaicism. The analysis also indicated that this duplication arose during spermatogenesis. The microhomology in the breakpoint was found and suggested that this duplication could be formed by a coupled homologous and non-homologous recombination mechanism.
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Duplicación de Gen , Mutación , Globinas alfa/genética , Talasemia alfa/diagnóstico , Talasemia alfa/genética , Globinas beta/genética , Talasemia beta/diagnóstico , Talasemia beta/genética , Alelos , Niño , Análisis Mutacional de ADN , Genotipo , Humanos , Patrón de Herencia , MasculinoRESUMEN
The major objective of this study was to investigate the anti-chronic nonbacterial prostatitis (CNP) mechanism of T. patula by metabolomics and network pharmacology. The study demonstrated that the flavonoids and polysaccharides of T. patula could alleviate prostatitis by improving the level of DHT, reducing the secretion of PSA and TNF-α. Besides, both could enhance Na+/K+-ATPase activity, decrease the O2 consumption, CO2 production, heat production, energy expenditure of rats and promote respiratory exchange ratio of rats. Up to 28 potential biomarkers and 8 key metabolic pathways related to the treatment of CNP were elucidated by the metabolomics analysis, including phenylalanine metabolism, taurine and hypotaurine metabolism, tryptophan metabolism etc. Network pharmacology prediction also reflected the potential mechanism was associated with tryptophan metabolism and energy pathway. Generally, the potential anti-CNP mechanism of flavonoids and polysaccharides of T. patula might be through reducing the expression of inflammation factors, adjusting the level of hormone and regulating the amino acid metabolism, energy metabolism and glucose and lipid metabolism.
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Biomarcadores , Metabolómica , Extractos Vegetales/farmacología , Prostatitis/tratamiento farmacológico , Prostatitis/metabolismo , Tagetes/química , Cromatografía Liquida , Enfermedad Crónica , Metabolismo Energético/efectos de los fármacos , Humanos , Masculino , Espectrometría de Masas , Redes y Vías Metabólicas/efectos de los fármacos , Metaboloma , Metabolómica/métodos , Extractos Vegetales/química , Extractos Vegetales/uso terapéutico , Prostatitis/diagnóstico , Prostatitis/etiologíaRESUMEN
Tagetespatula L. is a widely cultivated herbal medicinal plant in China and other countries. In this study, two new 2, 3-dihydrobenzofuran glucosides (1, 2) and fourteen known metabolites (3-16) were isolated from the stems and leaves of T. patula (SLT). The chemical structures of the isolated compounds were characterized comprehensively based on one- and two-dimensional NMR spectroscopy and high resolution mass spectrometry. Absolute configurations of compounds 1 and 2 were determined by ECD calculations. Compounds 1 and 2 exhibited moderate in vitro inhibitory activities against human gastric cancer cell lines (AGS) with IC50 values of 41.20 µmol/L and 30.43 µmol/L, respectively. The fingerprint profiles of stems and leaves of T. patula with three color types of flowers (Janie Yellow Bright, Jinmen Orange, Shouyao Red and Yellow color) were established by high-performance liquid chromatography (HPLC). Ten different batches of stems and leaves were examined as follow: Shouyao Red and Yellow color (1, 2, 3), Janie Yellow Bright (4, 5, 6, 7) and Jinmen Orange (8, 9, 10). Twenty-two common peaks were identified with similarity values ranging from 0.910 to 0.977. Meanwhile, the average peak area of SLT in the three types of flowers was different and it was the highest in Janie Yellow Bright.
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Fitoquímicos/análisis , Hojas de la Planta/química , Tallos de la Planta/química , Tagetes/química , Espectroscopía de Resonancia Magnética con Carbono-13 , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Cromatografía Líquida de Alta Presión/métodos , Humanos , Fitoquímicos/química , Fitoquímicos/aislamiento & purificación , Fitoquímicos/farmacologíaRESUMEN
Copy number variations (CNVs) can cause many genetic disorders and the structure analysis of unknown CNVs is important for clinical diagnosis. The human α-globin gene cluster lies close to the telomere of the short arm on chromosome 16. Copy number variations of this region produce excessive or insufficient α-globin chains which imbalances the ß-globin chains, resulting in thalassemia. However, these CNVs usually cannot be precisely defined by traditional methods. Here, we designed a technique strategy and applied it to identify two CNVs involving the α-globin gene cluster causing thalassemia in two Chinese families. A novel 282 kb duplication (αααα(282)) was identified in family A and a novel 235 kb deletion (--(235)) in family B. Proband A is a coinheritance of ß(CD41-42) and αααα(282) and showed severe ß-thalassemia intermedia phenotype. Proband B is a compound heterozygote of --(235)/α(CS)α genotype and was diagnosed with hemoglobin H disease. The clinical phenotypic features of the CNVs carriers were described, together with a complete picture of molecular structure of these rearrangements. Two CNVs are novel rearrangements in α-globin clusters and the αααα(282) is the first to identify the exact insert position of a duplication region from the telomere on chromosome 16. In a conclusion, successful identification and characterization of these two novel CNVs not only demonstrates the precision and effectiveness of our strategy in analyzing the structure of unknown CNVs, but also extended the spectrum of thalassemia and provide new examples for studying genomic recombination.
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Pueblo Asiatico/genética , Variaciones en el Número de Copia de ADN , Talasemia/genética , Globinas alfa/genética , Adulto , Anciano , Niño , Preescolar , China , Cromosomas Humanos Par 16/genética , Femenino , Predisposición Genética a la Enfermedad , Humanos , Masculino , Familia de Multigenes , LinajeRESUMEN
Gardner's syndrome is a rare autosomal dominant hereditary disease that is characterized by multiple colorectal polyps combined with extra-colonic presentation (such as osteoma or desmoid tumors) of familial adenomatous polyposis syndrome. Gardner's syndrome is caused by the mutation of the adenomatous polyposis coli (APC) gene, which is located at 5q21. The aim of the current study was to investigate the APC gene mutations present in a Han Chinese family diagnosed with Gardner's syndrome. The 38-year-old proband presented with clinical symptoms, and was later diagnosed with Gardner's syndrome. Genomic DNA was extracted from the peripheral venous blood of 150 normal controls as well as the family members of the proband. Analysis of the respective APC gene sequences was performed using PCR amplification and Sanger sequencing. Pathogenesis associated with the APC mutation was investigated using reverse-transcription quantitative PCR and determined through bioinformatics approaches. Haplotype analysis was performed to identify the genetic source of the mutation(s). In the initial screening for APC variants, the APC c.4621C>T variant was detected in the proband and his son, but was not detected in the proband's affected mother. The mRNA expression changed significantly according to age and the presence of the mutation in the blood of the patients. Haplotype analysis suggested the presence of maternal mosaicism for this mutation. Haplotype analysis revealed that the APC c.4621C>T variant in a patient with Gardner's syndrome was most likely derived from his mother through mosaicism. These results indicate the necessity to verify the possibility of gonadal mosaicism when a proband diagnosed with Gardner's syndrome appears to exhibit a de novo mutation.
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The balance between coagulation and fibrinolysis is essential for a successful pregnancy. This study aimed to explore the genetic variant of +1040C/T in the coding region of thrombin-activatable fibrinolysis inhibitor (TAFI) gene in women with recurrent spontaneous abortion (RSA) and in unrelated healthy controls and to investigate the possible association between TAFI +1040C/T polymorphism and RSA. Peripheral blood samples were collected from 137 Chinese patients with RSA and 103 unrelated healthy Chinese controls. The TAFI +1040C/T polymorphism was analyzed using SNaPshot SNP typing after DNA extraction. The frequency of the C allele was lower in RSA patients compared with the controls (0.78 vs 0.84). A subanalysis of the TAFI +1040C/T polymorphism in the 2 populations of RSA women (groups 2RSA and >2RSA) showed that the +1040CT genotype was significantly higher and the +1040CC genotype was significantly lower than from that found in controls. The allele +1040C was associated with a reduced risk of RSA in both group 2RSA (OR = 0.418, 95%CI, 0.255-0.685) and group >2RSA (OR = 0.473, 95%CI, 0.274-0.819) compared with controls. Our data indicate a protective role for TAFI +1040C allele against RSA, and may be associated with the genetic susceptibility of RSA.
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Aborto Habitual/genética , Carboxipeptidasa B2/genética , Fibrinólisis/efectos de los fármacos , Adulto , China , Estudios de Cohortes , Femenino , Humanos , EmbarazoRESUMEN
BACKGROUND: To evaluate the value of plasma D-dimer levels for the diagnosis of hepatocellular carcinoma (HCC). METHODS: The following databases were searched for relevant studies published from 1990 to 2018: Wanfang Data, SinoMed, VIP Chinese Science and Technology Periodicals Database, China National Knowledge Infrastructure, Superstar Journals Database, Cochrane library, and PubMed. The studies were selected according to the diagnosis of HCC by plasma D-dimer levels. Quality assessment of the diagnostic accuracy of the studied items was conducted for rigorous quality evaluation of the studies that met the inclusion criteria. After extracting the relevant data, Stata 15.0 software was adopted for the analysis of the diagnostic odds ratio (DOR), sensitivity, specificity, and positive and negative likelihood ratios. A summary receiver operating characteristic (SROC) curve was constructed to comprehensively evaluate the value of plasma D-dimer levels for the diagnosis of HCC. RESULTS: A total of 6 studies conducted in China with 475 cases in the patient groups and 727 in the control groups were included. The confidence level was expressed as the 95% confidence interval (CI). The pooled sensitivity, specificity, positive and negative likelihood ratios, and DOR of plasma D-dimer levels for the diagnosis of HCC were 0.75 (95% CIâ=â0.66-0.82), 0.93 (95% CIâ=â0.86-0.97), 11.4 (95% CIâ=â5.3-24.5), 0.27 (95% CIâ=â0.20-0.36), and 42 (95% CIâ=â19-93), respectively. The area under the SROC curve was 0.88 (95% CIâ=â0.85-0.91). CONCLUSIONS: Plasma D-dimer has high sensitivity and specificity, and is expected to be an important plasma marker for the clinical diagnosis of HCC. Due to the limited quality and quantity of the included studies, the above results should be further validated.
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Biomarcadores de Tumor/sangre , Carcinoma Hepatocelular/sangre , Productos de Degradación de Fibrina-Fibrinógeno/análisis , Neoplasias Hepáticas/diagnóstico , Carcinoma Hepatocelular/patología , China/epidemiología , Femenino , Humanos , Neoplasias Hepáticas/epidemiología , Neoplasias Hepáticas/patología , Masculino , Investigación Cualitativa , Estudios Retrospectivos , Sensibilidad y EspecificidadRESUMEN
Hereditary spherocytosis is a congenital red blood cell disorder. Typical clinical manifestations include anemia, jaundice and splenomegaly, which overlap with the thalassemia phenotype. Therefore, in high prevalence thalassemia regions, hereditary spherocytosis cases are often misdiagnosed. Here, a case once diagnosed as thalassemia, based on preliminary clinical examinations, underwent genetic testing in our laboratory, where analysis of globin gene mutations proved negative. We conducted both clinical and genetic analyses on the patient and his family. We collected clinical data, performed erythrocyte membrane protein analysis by SDS-PAGE and sequenced the ANK1 gene. We also investigated pathogenic mechanisms through cDNA sequencing and literature studies. From patient clinical data, we diagnosed the patient with moderate to severe hereditary spherocytosis, rather than thalassemia. SDS-PAGE data showed that Ankyrin protein expression was reduced. Sequencing of genomic DNA identified a frameshift mutation (ANK1:c.2394_2397del CAGT). cDNA sequencing showed that the expression of a mutant allele was significantly decreased. Our study corrected a clinical misdiagnosis and confirmed the diagnosis of hereditary spherocytosis in this patient. Identification of such causative mutations is important for accurate downstream patient therapy and is critically important for the prevention/detection of another affected birth. Additionally, the disruption of mRNA transcribed from the mutant allele resulted in a significant reduction in Ankyrin expression and was speculatively considered the pathogenic mechanism behind this mutation.
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Ancirinas/genética , Nucleótidos/genética , Eliminación de Secuencia/genética , Esferocitosis Hereditaria/diagnóstico , Esferocitosis Hereditaria/genética , Alelos , Niño , Errores Diagnósticos , Mutación del Sistema de Lectura/genética , Humanos , Masculino , Mutación/genética , Fenotipo , ARN Mensajero/genética , Talasemia/genéticaRESUMEN
INTRODUCTION: Although mutations in the human beta-globin gene cluster are essentially point mutations, several large deletions have been described in recent years. METHODS: We have identified a novel 223 kb deletion in a Chinese patient by multiplex ligation-dependent probe amplification and characterized it by next-generation sequencing, Gap-PCR, and DNA sequence analysis. RESULTS: The deletion extends from the 3'UTR of the δ globin gene (HBD) to 215 kb downstream of the HBB. Compound heterozygous with the typical ß-thalassemia-CD41-42(-CTTT) mutation, the proband presented with microcytosis and hypochromic red cells, and required regulate transfusion. The patient was clinically diagnosed with thalassemia major. CONCLUSION: Our study widens the mutation spectrum of ß-thalassemia. In addition, this case may spark future studies of the regulatory regions of the beta-globin gene cluster.
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Secuencia de Bases , Heterocigoto , Familia de Multigenes , Eliminación de Secuencia , Globinas beta/genética , Talasemia beta/genética , Pueblo Asiatico , China , Femenino , Humanos , Recién NacidoRESUMEN
RATIONALE: Dyskeratosis congenita (DC) is a rare inherited disease characterized by the classical mucocutaneous triad. Pulmonary fibrosis, bone marrow failure, and solid tumors are the main causes of mortality in DC. Pathogenic variants in TERT, TERC, and DKC1 have been identified in individuals with familial pulmonary fibrosis. Mutations in TINF2 gene have been reported to be associated with bone marrow failure in most cases. However, the relationship between TINF2 mutation and pulmonary fibrosis is not yet clear. PATIENT CONCERNS: Here, we report the case of a 32-year-old woman presented with irritating cough for 2 years and progressive breathlessness for 6 months. DIAGNOSES: The patient was diagnosed with DC based on the following clinical evidences. Along with some family members, she had the typical mucocutaneous triad and pulmonary fibrosis. A heterozygous mutation (c.844C>T), located in exon 6 of TINF2 gene, that changed arginine to cysteine (Arg282Cys) was identified in this proband by whole exome sequencing. INTERVENTIONS: The patient received corticosteroid therapy but refused to receive lung transplantation. OUTCOMES: The proband died of respiratory failure 4 months after the diagnosis. The missense mutation was located in the conserved region of TINF2 gene and predicted to be deleterious by altering the protein structure. LESSONS: Lung transplantation should be considered for improved survival of patients with DC, and pulmonary fibrosis. Whole exome and whole genome sequencing should be widely used in the identification of such rare genetic variants for clinical diagnosis. The study of DC with pulmonary fibrosis can provide a more appropriate means of clinical research and therapy to the unfortunate patients who suffer from this rare disorder.
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Disqueratosis Congénita/genética , Mutación Missense , Fibrosis Pulmonar/genética , Proteínas de Unión a Telómeros/genética , Corticoesteroides/uso terapéutico , Adulto , Disqueratosis Congénita/complicaciones , Resultado Fatal , Femenino , Humanos , Linaje , Fibrosis Pulmonar/complicaciones , Fibrosis Pulmonar/tratamiento farmacológicoRESUMEN
Tooth development is a complex process that involves precise and time-dependent orchestration of multiple genetic, molecular, and cellular interactions. Ameloblastin (AMBN, also named "amelin" or "sheathlin") is the second most abundant enamel matrix protein known to have a key role in amelogenesis. Amelogenesis imperfecta (AI [MIM: 104500]) refers to a genetically and phenotypically heterogeneous group of conditions characterized by inherited developmental enamel defects. The hereditary dentin disorders comprise a variety of autosomal-dominant genetic symptoms characterized by abnormal dentin structure affecting either the primary or both the primary and secondary teeth. The vital role of Ambn in amelogenesis has been confirmed experimentally using mouse models. Only two cases have been reported of mutations of AMBN associated with non-syndromic human AI. However, no AMBN missense mutations have been reported to be associated with both human AI and dentin disorders. We recruited one kindred with autosomal-dominant amelogenesis imperfecta (ADAI) and dentinogenesis imperfecta/dysplasia characterized by generalized severe enamel and dentin defects. Whole exome sequencing of the proband identified a novel heterozygous C-T point mutation at nucleotide position 1069 of the AMBN gene, causing a Pro to Ser mutation at the conserved amino acid position 357 of the protein. Exfoliated third molar teeth from the affected family members were found to have enamel and dentin of lower mineral density than control teeth, with thinner and easily fractured enamel, short and thick roots, and pulp obliteration. This study demonstrates, for the first time, that an AMBN missense mutation causes non-syndromic human AI and dentin disorders.
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Amelogénesis Imperfecta/genética , Dentina/anomalías , Secuenciación del Exoma , Mutación Missense , Adulto , Células Cultivadas , China , Codón , Dentina/ultraestructura , Femenino , Humanos , Masculino , Repeticiones de Microsatélite , Microscopía Electrónica de Rastreo , Persona de Mediana Edad , Linaje , ARN/análisis , TransfecciónRESUMEN
Hemoglobinopathies are among the most common autosomal-recessive disorders worldwide. A comprehensive next-generation sequencing (NGS) test would greatly facilitate screening and diagnosis of these disorders. An NGS panel targeting the coding regions of hemoglobin genes and four modifier genes was designed. We validated the assay by using 2522 subjects affected with hemoglobinopathies and applied it to carrier testing in a cohort of 10,111 couples who were also screened through traditional methods. In the clinical genotyping analysis of 1182 ß-thalassemia subjects, we identified a group of additional variants that can be used for accurate diagnosis. In the molecular screening analysis of the 10,111 couples, we detected 4180 individuals in total who carried 4840 mutant alleles, and identified 186 couples at risk of having affected offspring. 12.1% of the pathogenic or likely pathogenic variants identified by our NGS assay, which were undetectable by traditional methods. Compared with the traditional methods, our assay identified an additional at-risk 35 couples. We describe a comprehensive NGS-based test that offers advantages over the traditional screening/molecular testing methods. To our knowledge, this is among the first large-scale population study to systematically evaluate the application of an NGS technique in carrier screening and molecular diagnosis of hemoglobinopathies.
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Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Pruebas Genéticas , Técnicas de Genotipaje , Hemoglobinopatías/diagnóstico , Hemoglobinopatías/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Adolescente , Adulto , Estudios de Casos y Controles , China/epidemiología , Índices de Eritrocitos , Estudios de Asociación Genética/métodos , Tamización de Portadores Genéticos , Pruebas Genéticas/métodos , Variación Genética , Genotipo , Geografía Médica , Hemoglobinopatías/epidemiología , Hemoglobinas Anormales/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Persona de Mediana Edad , Fenotipo , Polimorfismo de Nucleótido Simple , Vigilancia de la Población , Prevalencia , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad , Adulto JovenRESUMEN
This research analyzes the regulation of ischemic tolerance in hibernating thirteen-lined ground squirrels (Spermophilus tridecemlineatus). Hibernation is studied because it represents a unique state of reversible suspended animation associated with tolerance to an otherwise lethal reduction of core body temperature and metabolism. An integral aspect of hibernation is the profound decrease of cerebral perfusion without neurological damage. As such, hibernation serves as a model for studying natural tolerance to brain ischemia. Identification of regulatory mechanisms that control hibernation in ground squirrels may guide efforts to develop improved treatments for stroke and brain trauma. It was previously shown that phosphorylation of Akt (protein kinase B), an insulin-like growth factor-regulated serine/threonine kinase, was significantly reduced as was its kinase activity in hibernating thirteen-lined ground squirrels. Here we studied the forkhead (FH) in rhabdomyosarcoma (FKHR) transcription factor, which is controlled by Akt signaling and is involved in regulating cell cycle progression and cell death. A cDNA derived from brains of S. tridecemlineatus, encoding a specific FKHR transcription factor, FoxO1a, was cloned and sequenced, and the amino acid sequence of the protein was deduced. FoxO1a is composed of 653 amino acids and has a predicted molecular mass of 69.4 kilodaltons (kDa). Here, for the first time, we report the contrary expression of phosphorylation of two members in the insulin-like growth factor signaling pathway during hibernation (i.e., phosphorylated FKHR was significantly up-regulated as phosphorylation of its upstream kinase, Akt, was significantly down-regulated). Further study is required to identify the possible connection between FoxO1a and Akt activity and the possible of such interactions in hibernation.
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Sciuridae/genética , Factores de Transcripción/genética , Animales , Secuencia de Bases , Clonación Molecular , Cartilla de ADN , Hibernación , Illinois , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sciuridae/fisiología , Estaciones del AñoRESUMEN
Hibernation, an adaptive response for energy conservation in mammals, involves a variety of physiological changes. Melatonin is linked with the regulation of core body temperature and intervenes in generating circadian cycles; its role in seasonal (circannual) rhythms of hibernation is explored here. Melatonin is primarily produced in the pineal gland. Since arylalkylamine-N-acetyltransferase (AA-NAT) is the rate-limiting enzyme for synthesizing melatonin, AA-NAT gene expression was investigated to assess the possible role of melatonin in hibernation. The findings presented here utilized combined in situ hybridization and immunohistochemistry methodologies to evaluate the AA-NAT mRNA expression in brains of both hibernating and non-hibernating ground squirrels. Brains were examined for the expression of AA-NAT mRNA using a oligonucleotide AA-NAT probe; antibody against neurofilament-70 (NF-70) was used as a neuronal marker. All hibernating animals expressed significantly (P<0.01) elevated levels of AA-NAT mRNA in both the epithalamic medial habenular nuclei (MHb) area and the hypothalamic suprachiasmatic nuclei (SCN), which is also known as the master biologic clock. These findings represent the first demonstration of the expression of mRNA encoding for AA-NAT in the extra-pineal (i.e. SCN and MHb) sites of thirteen-lined ground squirrels and indicate that the habenular nucleus may be an important supplementary location for melatonin biosynthesis. The data presented here indicate that AA-NAT gene is one of the few specific genes up-regulated during hibernation and suggest that elevation of its expression in SCN and MHb may play an essential role in the generation and maintenance of hibernation.
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Arilamina N-Acetiltransferasa/genética , Regulación Enzimológica de la Expresión Génica/fisiología , Habénula/enzimología , Hibernación/genética , Melatonina/biosíntesis , Sciuridae/genética , Núcleo Supraquiasmático/enzimología , Animales , Ritmo Circadiano/genética , Habénula/citología , Inmunohistoquímica , Proteínas de Filamentos Intermediarios/metabolismo , Neuronas/citología , Neuronas/enzimología , Glándula Pineal/metabolismo , ARN Mensajero/metabolismo , Sciuridae/anatomía & histología , Sciuridae/metabolismo , Núcleo Supraquiasmático/citología , Regulación hacia Arriba/genéticaRESUMEN
Hibernation in mammals is a reversible state of suspended animation associated with tolerance to an otherwise lethal reduction of core body temperature and metabolism. An integral aspect of hibernation is tolerance to a profound decrease of cerebral perfusion. Identification of regulatory mechanisms that control hibernation in ground squirrels can guide efforts to develop improved treatment for stroke and brain trauma. In this study, we show in multiple tissues that S473 phosphorylation of Akt (Protein kinase B), a phosphatidylinositol-3 kinase-regulated serine/threonine kinase, was significantly reduced (P<0.001) as was its kinase activity (P=0.023) in the 13-lined ground squirrel, Spermophilus tridecemlineatus, during hibernation. T308 phosphorylation of Akt was relatively preserved. Brain immunohistochemical staining confirmed these results. In hibernating animals, reduction of immunoreactive phospho (S473)-Akt was noted throughout the brain. Akt is a key molecule in the insulin/insulin-like growth factor signal transduction pathway, which plays a critical role in the balance between survival and apoptosis. The data presented here raise the possibility that down-regulation of Akt phosphorylation plays a regulatory role in hibernation. This would resemble dauer larva formation in Caenorhabditis elegans where Akt inhibition is associated with energy conservation, fat storage, expression of antioxidant enzymes and growth arrest.
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Encéfalo/metabolismo , Hibernación/fisiología , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Animales , Apoptosis/fisiología , Regulación hacia Abajo , Inmunohistoquímica , Riñón/metabolismo , Hígado/metabolismo , Músculo Esquelético/metabolismo , Miocardio/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt , Sciuridae , Transducción de Señal , Somatomedinas/metabolismoRESUMEN
Plasma from hibernating (HIB) woodchucks (Marmota monax) or 13-lined ground squirrels (Ictidomys tridecemlineatus) suppressed (3)H-thymidine uptake in mouse spleen cell cultures stimulated with Concanavalin A (ConA); plasma from non-hibernating animals were only slightly inhibitory. Maximum inhibition occurred when HIB plasma was added to the cultures prior to ConA. After HPLC size exclusion chromatography of the HIB ground squirrel plasma, a single fraction (fraction-14) demonstrated inhibitory activity. Assay of fraction-14 from 8 HIB squirrels showed inhibition ranging from 13 to 95%; inhibition was correlated to the time the squirrels were exposed to cold prior to hibernation. Western blot analysis showed the factor to be a large molecular weight protein (>300 kDa), and mass spectrometry identified sequences that were 100% homologous with alpha-2-macroglobulin from humans and other species. These findings indicate a hibernation-related protein that may be responsible for immune system down regulation.