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1.
PLoS One ; 14(12): e0225423, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31790451

RESUMO

INTRODUCTION: Positive fluid balance is a prognostic factor for mortality in patients with sepsis; however, the association between cumulated fluid balance (CFB) and sepsis-induced multi-organ dysfunction syndrome (MODS) has yet to be elucidated. In this study, we sought to determine whether CFB is correlated with MODS and mortality in cases of septic shock. METHODS: The study retrospectively recruited patients with septic shock from the intensive care unit of a tertiary care hospital. Multiple organ dysfunction syndrome (MODS) was identified as sequential organ failure assessment (SOFA) score ≥ 2 in more than one organ system. The CFB is the sum of all daily intake and output. An independent t-test, single and multivariate logistic regression, the receiver operating characteristic (ROC) curves, and the Pearson correlation coefficient were used to determine whether a relationship exists between CFB and the development of MODS and mortality. RESULTS: Among the 104 patients enrolled in the study, 58 (55.8%) survived more than 28 days, and 73 (70.2%) developed MODS on day 3. The values of CFB in the first 24 hours and 72 hours after diagnosis of septic shock in patients with MODS were higher than these in patients without MODS (1086.6 ± 176.3 vs. 325.5 ± 205.7 ml, p = 0.013 and 2408 ± 361 vs. 873.1 ± 489 ml, p < 0.0001). In a multivariate logistic regression, the independent factors associated with the development of MODS on day 3 were APACHE II score at ICU admission (27.6 ± 7.6 in patients with MODS vs. 20.5 ± 6.4 in those without; O.R. 1.18; 95% C.1 I. 1.08-1.30; p < 0.001), disseminated intravascular coagulopathy (DIC) (n = 28; 38.4% vs. n = 2; 6.5%; O.R. 23.67; 95% C.I. 3.58-156.5; p = 0.001), and CFB in the first 72 hours (72-hr CFB) > median (1767.50ml) (n = 41; 56.2% vs. n = 11; 35.5%; O.R. 3.67; 95% C.I., 1.18-11.40; p = 0.024). Moreover, a multivariate logistic regression also identified neoplasm (n = 25; 54.3% vs. n = 17; 29.3%; O.R. 3.45; 95% C.I. 1.23-10.0; p = 0.019) and 72-hr CFB > median (n = 30; 65.2% vs. n = 21; 36.2%; O.R. 4.13; 95% C.I. 1.34-12.66; p = 0.013) as independent factors associated with 28-day mortality. 72-hr CFB values were strongly correlated with the SOFA score (r = 0.445, p < 0.0001). The area under the ROC curve revealed that 72-hr CFB has good discriminative power in associating the development of MODS (0.644, p = 0.002) and predicting subsequent 28-day mortality (0.704, p < 0.0001). CONCLUSIONS: 72-hr CFB appears to be correlated with the likelihood of developing MODS and mortality in patients with septic shock. Thus, it appears that 72-hr CFB could perhaps be used as an indicator for MODS and a predictor for mortality in those patients.

2.
Science ; 366(6466): 714-723, 2019 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-31699932

RESUMO

Activating mutations in PIK3CA are frequent in human breast cancer, and phosphoinositide 3-kinase alpha (PI3Kα) inhibitors have been approved for therapy. To characterize determinants of sensitivity to these agents, we analyzed PIK3CA-mutant cancer genomes and observed the presence of multiple PIK3CA mutations in 12 to 15% of breast cancers and other tumor types, most of which (95%) are double mutations. Double PIK3CA mutations are in cis on the same allele and result in increased PI3K activity, enhanced downstream signaling, increased cell proliferation, and tumor growth. The biochemical mechanisms of dual mutations include increased disruption of p110α binding to the inhibitory subunit p85α, which relieves its catalytic inhibition, and increased p110α membrane lipid binding. Double PIK3CA mutations predict increased sensitivity to PI3Kα inhibitors compared with single-hotspot mutations.

3.
J Virol ; 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31723026

RESUMO

Kaposi's sarcoma associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma (KS), an acquired immunodeficiency syndrome (AIDS)-defining cancer with abnormal angiogenesis. The high incidence of KS in human immunodeficiency viruses (HIV)-infected AIDS patients has been ascribed to HIV-1 and KSHV interaction, focusing on secretory proteins. HIV-1 secreted protein HIV-Tat has been found to synergize with KSHV lytic proteins to induce angiogenesis. However, the impact and underlying mechanisms of HIV-Tat in KSHV-infected endothelial cells undergoing viral lytic reactivation remain unclear. Here, we identified LINC00313 as a novel KSHV reactivation-activated long non-coding RNA (lncRNA) that interacts with HIV-Tat. We found that LINC00313 overexpression inhibits cell migration, invasion and tube formation, and this suppressive effect was relieve by HIV-Tat. In addition, LINC00313 bound to polycomb repressive complex 2 (PRC2) complex components and this interaction was disrupted by HIV-Tat suggesting that LINC00313 may mediate transcription repression through recruitment of PRC2 and HIV-Tat alleviates repression through disruption of this association. This notion was further supported by bioinformatics analysis of transcriptome profiles in LINC00313 overexpression combined with HIV-Tat treatment. Ingenuity Pathway Analysis (IPA) showed that LINC00313 overexpression negatively regulates cell movement and migration pathways, and enrichment of these pathways was absent in the presence of HIV-Tat. Collectively, our results illustrate that an angiogenic repressive lncRNA, LINC00313 that is up-regulated during KSHV reactivation interacts with HIV-Tat to promote endothelial cell motility. These results demonstrate that a lncRNA serves as a novel connector in HIV-KSHV interactions.IMPORTANCE KS is a prevalent tumor associated with two distinct viral infections, KSHV and HIV. Since KSHV and HIV infect distinct cell types, the viral-viral interaction associated with KS formation has focused on secretory factors. HIV-Tat is a well-known RNA binding protein secreted by HIV. Here, we revealed LINC00313, an lncRNA up-regulated during KSHV lytic reactivation, as a novel HIV-Tat interacting lncRNA that potentially mediates HIV-KSHV interactions. We found that LINC00313 can repress endothelial cell angiogenesis-related properties potentially through interacting with chromatin remodeling complex PRC2 and down-regulation of cell migration regulating genes. Interaction between HIV-Tat and LINC00313 contributed to dissociation of PRC2 from LINC00313 and disinhibition of LINC00313-induced repression of cell motility. Given that lncRNAs are emerging as key players in tissue physiology and disease progression, including cancer, the mechanism identified in this study may help decipher the mechanisms underlying KS pathogenesis induced by HIV and KSHV co-infection.

4.
Nat Commun ; 10(1): 4180, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31519888

RESUMO

Algae produce the largest amount of oxygen on earth and are invaluable for human nutrition and biomedicine, as well as for the chemical industry, energy production and agriculture. The mechanisms by which algae can detect and respond to changes in their environments can rely on membrane receptors, including TRP ion channels. Here we present a 3.5-Å resolution cryo-EM structure of the transient receptor potential (TRP) channel crTRP1 from the alga Chlamydomonas reinhardtii that opens in response to increased temperature and is positively regulated by the membrane lipid PIP2. The structure of crTRP1 significantly deviates from the structures of other TRP channels and has a unique 2-fold symmetrical rose-shape architecture with elbow domains and ankyrin repeat domains submerged and dipping into the membrane, respectively. Our study provides a structure of a TRP channel from a micro-organism and a structural framework for better understanding algae biology and TRP channel evolution.

5.
Cancer Sci ; 110(10): 3204-3214, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31385416

RESUMO

Peritoneal dissemination is the most frequent metastatic route of ovarian cancer. However, due to the high heterogeneity in ovarian cancer, most conventional studies lack parental tumor controls relevant to metastases and, thus, it is difficult to trace the molecular changes of cancer cells along with the selection by the abdominal microenvironment. Here, we established an in vivo mouse peritoneal dissemination scheme that allowed us to select more aggressive sublines from parental ovarian cancer cells, including A2780 and SKOV-3. Microarray and gene profiling analyses indicated that autophagy-related genes were enriched in selected malignant sublines. Detection of LC3-II, p62 and autophagic puncta demonstrated that these malignant variants were more sensitive to autophagic induction when exposed to diverse stress conditions, such as high cell density, starvation and drug treatment. As compared with parental A2780, the selected variant acquired the ability to grow better under high-density stress; however, this effect was reversed by addition of autophagic inhibitors or knockdown of ATG5. When analyzing the clinical profiles of autophagy-related genes identified to be enriched in malignant A2780 variant, 73% of them had prognostic significance for the survival of ovarian cancer patients. Taken together, our findings indicate that an increase in autophagic potency among ovarian cancer cells is crucial for selection of metastatic colonies in the abdominal microenvironment. In addition, the derived autophagic gene profile can not only predict prognosis well but can also be potentially applied to precision medicine for identifying those ovarian cancer patients suitable for taking anti-autophagy cancer drugs.


Assuntos
Proteínas Relacionadas à Autofagia/genética , Perfilação da Expressão Gênica/métodos , Proteínas Associadas aos Microtúbulos/genética , Neoplasias Ovarianas/patologia , Neoplasias Peritoneais/secundário , Proteínas de Ligação a RNA/genética , Animais , Autofagia , Linhagem Celular Tumoral , Sobrevivência Celular , Feminino , Humanos , Camundongos , Transplante de Neoplasias , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Neoplasias Peritoneais/genética , Neoplasias Peritoneais/patologia , Medicina de Precisão , Prognóstico , Microambiente Tumoral
6.
Sci Adv ; 5(7): eaaw2326, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31309145

RESUMO

The highly conserved Elongator complex modifies transfer RNAs (tRNAs) in their wobble base position, thereby regulating protein synthesis and ensuring proteome stability. The precise mechanisms of tRNA recognition and its modification reaction remain elusive. Here, we show cryo-electron microscopy structures of the catalytic subcomplex of Elongator and its tRNA-bound state at resolutions of 3.3 and 4.4 Å. The structures resolve details of the catalytic site, including the substrate tRNA, the iron-sulfur cluster, and a SAM molecule, which are all validated by mutational analyses in vitro and in vivo. tRNA binding induces conformational rearrangements, which precisely position the targeted anticodon base in the active site. Our results provide the molecular basis for substrate recognition of Elongator, essential to understand its cellular function and role in neurodegenerative diseases and cancer.

7.
Toxins (Basel) ; 11(5)2019 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-31072027

RESUMO

Aflatoxins are carcinogenic secondary metabolites of fungi that contaminate many staple crops and foods. Aflatoxin contamination is a worldwide problem, especially in developing countries, posing health hazards, e.g., causing aflatoxicosis and hepatocellular carcinoma, and even death. Biological solutions for aflatoxin detoxification are environmentally friendly and a cheaper alternative than chemical methods. The aims of the current study were to investigate: (1) the ability of MSMEG_5998, an aflatoxin-degrading F420H2-dependent reductase from Mycobacterium smegmatis, to degrade aflatoxin B1 (AFB1) and reduce AFB1-caused damage in HepG2 cell culture model; and (2) whether a thioredoxin (Trx) linkage of MSMEG_5998 enhanced the enzyme activity. We show that Trx-linked MSMEG_5998 degraded 63% AFB1 and native MSMEG_5998 degraded 31% after 4 h at 22 °C, indicating that the Trx-linked enzyme had a better AFB1-degrading ability. In a HepG2 cell culture model, Trx-linked MSMEG_5998 reduced DNA damage and p53-mediated apoptosis caused by AFB1 to a greater extent than the native enzyme. These findings suggest that Trx-linked MSMEG_5998 could potentially be developed to protect the liver from AFB1 damage, or as a candidate protein to reduce AFB1-related toxicity in animals.

8.
Nat Commun ; 10(1): 625, 2019 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-30733442

RESUMO

The Elongator complex catalyzes posttranscriptional tRNA modifications by attaching carboxy-methyl (cm5) moieties to uridine bases located in the wobble position. The catalytic subunit Elp3 is highly conserved and harbors two individual subdomains, a radical S-adenosyl methionine (rSAM) and a lysine acetyltransferase (KAT) domain. The details of its modification reaction cycle and particularly the substrate specificity of its KAT domain remain elusive. Here, we present the co-crystal structure of bacterial Elp3 (DmcElp3) bound to an acetyl-CoA analog and compare it to the structure of a monomeric archaeal Elp3 from Methanocaldococcus infernus (MinElp3). Furthermore, we identify crucial active site residues, confirm the importance of the extended N-terminus for substrate recognition and uncover the specific induction of acetyl-CoA hydrolysis by different tRNA species. In summary, our results establish the clinically relevant Elongator subunit as a non-canonical acetyltransferase and genuine tRNA modification enzyme.


Assuntos
Histona Acetiltransferases/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Domínio Catalítico , Histona Acetiltransferases/química , Methanocaldococcus/metabolismo , RNA de Transferência/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Especificidade por Substrato
9.
J Clin Monit Comput ; 2019 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-30725265

RESUMO

Capnography involves the measurement of end-tidal CO2 (EtCO2) values to detect hypoventilation in patients undergoing sedation. In a previous study, we reported that initiating a flexible bronchoscopy (FB) examination only after detecting signs of hypoventilation could reduce the risk of hypoxemia without compromising the tolerance of the patient for this type of intervention. We hypothesize that hypoventilation status could be determined with greater precision by combining thoracic impedance-based respiratory signals, RESP, and EtCO2 signals obtained from a nasal-oral cannula. Retrospective analysis was conducted on RESP and EtCO2 waveforms obtained from patients during the induction of sedation using propofol for bronchoscopic examination in a previous study. EtCO2 waveforms associated with hypoventilation were then compared with RESP patterns, patient variables, and sedation outcomes. Signals suitable for analysis were obtained from 44 subjects, 42 of whom presented indications of hypoventilation, as determined by EtCO2 waveforms. Two subtypes of hypoventilation were identified by RESP: central-predominant (n = 22, flat line RESP pattern) and non-central-predominant (n = 20, RESP pattern indicative of respiratory effort with upper airway collapse). Compared to cases of non-central-predominant hypoventilation, those presenting central-predominant hypoventilation during induction were associated with a lower propofol dose (40.2 ± 18.3 vs. 60.8 ± 26.1 mg, p = 0.009), a lower effect site concentration of propofol (2.02 ± 0.33 vs. 2.38 ± 0.44 µg/ml, p = 0.01), more rapid induction (146.1 ± 105.5 vs. 260.9 ± 156.2 s, p = 0.01), and lower total propofol dosage (96.6 ± 41.7 vs. 130.6 ± 53.4 mg, p = 0.04). Hypoventilation status (as revealed by EtCO2 levels) could be further classified by RESP into central-predominant or non-central-predominant types. It appears that patients with central-predominant hypoventilation are more sensitive to propofol during the induction of sedation. RESP values could be used to tailor sedation management specifically to individual patients.

10.
Cell ; 175(6): 1546-1560.e17, 2018 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-30500537

RESUMO

Mammalian folate metabolism is comprised of cytosolic and mitochondrial pathways with nearly identical core reactions, yet the functional advantages of such an organization are not well understood. Using genome-editing and biochemical approaches, we find that ablating folate metabolism in the mitochondria of mammalian cell lines results in folate degradation in the cytosol. Mechanistically, we show that QDPR, an enzyme in tetrahydrobiopterin metabolism, moonlights to repair oxidative damage to tetrahydrofolate (THF). This repair capacity is overwhelmed when cytosolic THF hyperaccumulates in the absence of mitochondrially produced formate, leading to THF degradation. Unexpectedly, we also find that the classic antifolate methotrexate, by inhibiting its well-known target DHFR, causes even more extensive folate degradation in nearly all tested cancer cell lines. These findings shed light on design features of folate metabolism, provide a biochemical basis for clinically observed folate deficiency in QDPR-deficient patients, and reveal a hitherto unknown and unexplored cellular effect of methotrexate.

12.
Front Physiol ; 9: 723, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30013479

RESUMO

Purpose: We propose a phenotype-based artificial intelligence system that can self-learn and is accurate for screening purposes and test it on a Level IV-like monitoring system. Methods: Based on the physiological knowledge, we hypothesize that the phenotype information will allow us to find subjects from a well-annotated database that share similar sleep apnea patterns. Therefore, for a new-arriving subject, we can establish a prediction model from the existing database that is adaptive to the subject. We test the proposed algorithm on a database consisting of 62 subjects with the signals recorded from a Level IV-like wearable device measuring the thoracic and abdominal movements and the SpO2. Results: With the leave-one-subject-out cross validation, the accuracy of the proposed algorithm to screen subjects with an apnea-hypopnea index greater or equal to 15 is 93.6%, the positive likelihood ratio is 6.8, and the negative likelihood ratio is 0.03. Conclusion: The results confirm the hypothesis and show that the proposed algorithm has potential to screen patients with SAS.

13.
J Cell Physiol ; 233(1): 497-505, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28294332

RESUMO

The tautomeric pair of garcinielliptone FC (GFC) is a novel tautomeric pair of polyprenyl benzophenonoid isolated from the pericarps of Garcinia subelliptica Merr. (G. subelliptica, Clusiaceae), a tree with abundant sources of polyphenols. Our previous report demonstrated that GFC induced apoptosis on various types of human cancer cell lines including chemoresistant human colorectal cancer HT-29 cells. In the present study, we observed that many autophagy-related genes in GFC-treated HT-29 cells were up- and down-regulated using a cDNA microarray containing oncogenes and kinase genes. GFC-induced autophagy of HT-29 cells was confirmed by observing the formation of acidic vesicular organelles, LC3 puncta, and double-membrane autophagic vesicles using flow cytometry, confocal microscopy, and transmission electron microscopy, respectively. Inhibition of AKT/mTOR/P70S6K signaling as well as formation of Atg5-Atg12 and PI3K/Beclin-1 complexes were observed using Western blot. Administration of autophagy inhibitor (3-methyladenine and shRNA Atg5) and apoptosis inhibitor Z-VAD showed that the GFC-induced autophagy was cytotoxic form and GFC-induced apoptosis enhanced GFC-induced autophagy. Our data suggest the involvement of autophagy and apoptosis in GFC-induced anticancer mechanisms of human colorectal cancer.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Autofagia/efeitos dos fármacos , Neoplasias Colorretais/tratamento farmacológico , Triterpenos/farmacologia , Apoptose/efeitos dos fármacos , Proteína 12 Relacionada à Autofagia/genética , Proteína 12 Relacionada à Autofagia/metabolismo , Proteína 5 Relacionada à Autofagia/genética , Proteína 5 Relacionada à Autofagia/metabolismo , Proteína Beclina-1/genética , Proteína Beclina-1/metabolismo , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/ultraestrutura , Relação Dose-Resposta a Droga , Regulação Neoplásica da Expressão Gênica , Células HT29 , Humanos , Fosfatidilinositol 3-Quinase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Interferência de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Fatores de Tempo , Transfecção
14.
Oncotarget ; 8(57): 97602-97612, 2017 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-29228636

RESUMO

The choice of a first-line therapy for lung cancer is a crucial decision that can impact the survival as well as the quality of life of a patient. Inhibitors of epidermal growth factor receptor (EGFR) such as afatinib, erlotinib, and gefitinib have previously been used to treat non-small cell lung cancer harboring favorable EGFR mutations. Although afatinib has greater efficacy than other EGFR inhibitors, adverse events related to its use can result in the discontinuation of the therapy. In this study, we compared the therapeutic efficacy in lung cancer patients of a regimen of 40 mg/day of afatinib with that of a lower dose regimen of <40 mg/day resulting either from a lower starting dose of 30 mg/day or dose adjustment. Seventy-nine patients were treated with 40 mg/day and 67 received de-escalated doses of <40 mg/day. There was no significant difference in the clinical characteristics of the two groups except that the proportion of patients with a body weight of 50 kg or more was greater in the 40 mg/day group. Otherwise, there were no significant differences between the two groups in the average time to treatment failure (TTF), the rates at which the administration of a second-line therapy was necessary, or the frequency and severity of adverse events. Overall, these results suggest that it is possible to calibrate the dosage of afatinib to suit individual patient parameters such as low body weight, and that such calibration can be advised based on the given patient's individual experience of the drug.

15.
Taiwan J Ophthalmol ; 7(2): 108-111, 2017 Apr-Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29018767

RESUMO

A 15-year-old boy presented with progressive myoclonic epilepsy and unbalance gaits for 4 years. Slit lamp examination showed a punctate cataract and funduscopic examination revealed bilateral macular cherry-red spots. Macular scan of spectral domain optical coherence tomography (SD-OCT) showed hyperreflectivity of the inner retinal layer and apparent hyperreflectivity of the photoreceptor layers in the foveal region. The clinical presentations were consistent with a Type I sialidosis which led to genetic analysis and revealed NEU1 mutation in this patient. He was under regular follow-up by ophthalmologist and neurologist. Sialidosis is a rare lysosomal storage disease resulting from a deficiency of alpha-N-acetyl neuraminidase caused by a mutation in the NEU1 gene. This results in abnormal intracellular accumulation of sialyloligosaccharides in brain neurons and ganglion cells of the retina. SD-OCT is a useful tool in detecting macular cherry-red spot and has a role in evaluating the extent of ganglion cell damage. It can aid in the differential diagnosis and long-term follow-up of the neurological metabolic disorders.

16.
Sci Rep ; 7(1): 8685, 2017 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-28819181

RESUMO

We hypothesize that capnography could detect hypoventilation during induction of bronchoscopic sedation and starting bronchoscopy following hypoventilation, may decrease hypoxemia. Patients were randomized to: starting bronchoscopy when hypoventilation (hypopnea, two successive breaths of at least 50% reduction of the peak wave compared to baseline or apnea, no wave for 10 seconds) (Study group, n = 55), or when the Observer Assessment of Alertness and Sedation scale (OAAS) was less than 4 (Control group, n = 59). Propofol infusion was titrated to maintain stable vital signs and sedative levels. The hypoventilation during induction in the control group and the sedative outcome were recorded. The patient characteristics and procedures performed were similar. Hypoventilation was observed in 74.6% of the patients before achieving OAAS < 4 in the control group. Apnea occurred more than hypopnea (p < 0.0001). Hypoventilation preceded OAAS < 4 by 96.5 ± 88.1 seconds. In the study group, the induction time was shorter (p = 0.03) and subjects with any two events of hypoxemia during sedation, maintenance or recovery were less than the control group (1.8 vs. 18.6%, p < 0.01). Patient tolerance, wakefulness during sedation, and cooperation were similar in both groups. Significant hypoventilation occurred during the induction and start bronchoscopy following hypoventilation may decrease hypoxemia without compromising patient tolerance.

17.
Sci Signal ; 10(477)2017 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-28465413

RESUMO

Mutation in either of the genes encoding bone morphogenetic protein (BMP) 8A or 8B (Bmp8a or Bmp8b) causes postnatal depletion of spermatogonia in mice. We found that Bmp8a, but not Bmp8b, was expressed predominantly in the neonatal mouse spermatogonia. Although most BMPs induce activation of SMADs 1, 5, and 8 (SMAD1/5/8), but not SMADs 2 and 3 (SMAD2/3), we found that BMP8A induced signaling through both sets of transcription factors. In undifferentiated mouse spermatogonia, BMP8A activated SMAD1/5/8 through receptor complexes formed by ALK3 and either ACVR2A or BMPR2 and activated SMAD2/3 through receptor complexes formed by ALK5 and ACVR2A, ACVR2B, or TGFBR2. Signaling through SMAD2/3 promoted the proliferation of germ cells, whereas that through SMAD1/5/8 directed the subsequent differentiation of spermatogonia. BMP8A promoted spermatogenesis in cultured mouse testis explants, and the resulting spermatids were functionally competent for fertilization. These results suggest that the dual role of BMP8A in promoting proliferation and differentiation of spermatogonia may be exploited clinically to treat male infertility.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Diferenciação Celular , Proteínas Smad Reguladas por Receptor/metabolismo , Espermatogênese/fisiologia , Espermatogônias/citologia , Animais , Células Cultivadas , Humanos , Masculino , Camundongos , Camundongos Endogâmicos ICR , Transdução de Sinais , Espermatogônias/metabolismo
18.
Biomacromolecules ; 18(4): 1350-1355, 2017 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-28252955

RESUMO

The spider silk spinning process converts spidroins from an aqueous form to a tough fiber. This spinning process has been investigated by numerous researchers, and micelles or liquid crystals of spidroins have been reported to form silk fibers, which are bundles of silk microfibrils. However, the formation process of silk microfibrils has not been clarified previously. Here, we report that silk microfibrils are generated through the formation, homogenization, and linkage of liquid crystalline granules without micelle-like structures. Heterogeneous granules on the submicron to micron scale were observed in the storage sac, whereas homogeneous granules with diameters of approximately 100 nm were aligned along the tapering duct. In the spun fibers, the homogeneous granules were connected along the fiber axis. This is the first clear description of the formation of granule-based microfibrils in the spinning process, which is the key conversion process leading to the unique hierarchical structure of spider dragline.


Assuntos
Fibroínas/química , Cristais Líquidos/química , Microfibrilas/química , Aranhas , Animais , Feminino , Fibroínas/ultraestrutura , Cristais Líquidos/ultraestrutura , Microfibrilas/ultraestrutura , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Aranhas/anatomia & histologia
19.
Medicine (Baltimore) ; 95(43): e5101, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27787363

RESUMO

BACKGROUND: Alfentanil in combination with propofol produces a synergistic sedative effect in patients undergoing flexible bronchoscopy (FB). However, the use of this combination is controversial due to the risk of cardiopulmonary depression. The aim of this study was to evaluate the proper induction regimen of alfentanil in propofol target-controlled infusion for FB sedation. METHODS: One hundred seventy-three patients were assigned randomly into 5 regimens: Group 1 and 2, alfentanil 2.5 and 5 µg/kg, respectively, immediately before propofol administration; Group 3 and 4, alfentanil 2.5 and 5 µg/kg, respectively, 2 minutes before propofol administration; and Group 5, propofol administration alone to achieve the observer assessment of alertness and sedation scale 3∼2. The bronchoscopists, physicians in charge of sedation, and patients were blind to the regimens. Adverse events, drug dose, induction, procedure and recovery time, cough severity, and propofol injection related pain were recorded. RESULTS: The patients in groups 2 and 4 required a lower dose of propofol (P = 0.031 and 0.019, respectively) and shorter time (P = 0.035 and 0.010) than group 5 for induction. Patients in group 2 experienced more hypoxemia than those in group 5 during induction (P = 0.031). The physician in charge of sedation scored a lower severity of cough in the patients in group 4 than in groups 3 and 5. There were no differences in terms of propofol injection related pain among the groups. CONCLUSION: Alfentanil 5 µg/kg given immediately before propofol infusion cannot be recommended. Further study is required to define conclusions about alfentanil 2.5 and 5 µg/kg because of the low power rating of subgroup in the present study.


Assuntos
Alfentanil/administração & dosagem , Broncoscopia/métodos , Sedação Consciente/métodos , Anestésicos Intravenosos/administração & dosagem , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Propofol/administração & dosagem , Estudos Prospectivos , Resultado do Tratamento
20.
Nat Struct Mol Biol ; 23(9): 794-802, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27455459

RESUMO

During translation elongation, decoding is based on the recognition of codons by corresponding tRNA anticodon triplets. Molecular mechanisms that regulate global protein synthesis via specific base modifications in tRNA anticodons are receiving increasing attention. The conserved eukaryotic Elongator complex specifically modifies uridines located in the wobble base position of tRNAs. Mutations in Elongator subunits are associated with certain neurodegenerative diseases and cancer. Here we present the crystal structure of D. mccartyi Elp3 (DmcElp3) at 2.15-Å resolution. Our results reveal an unexpected arrangement of Elp3 lysine acetyltransferase (KAT) and radical S-adenosyl methionine (SAM) domains, which share a large interface and form a composite active site and tRNA-binding pocket, with an iron-sulfur cluster located in the dimerization interface of two DmcElp3 molecules. Structure-guided mutagenesis studies of yeast Elp3 confirmed the relevance of our findings for eukaryotic Elp3s and should aid in understanding the cellular functions and pathophysiological roles of Elongator.


Assuntos
Proteínas de Bactérias/química , Histona Acetiltransferases/química , RNA de Transferência/química , Domínio Catalítico , Chloroflexi/enzimologia , Cristalografia por Raios X , Ligação Proteica , Conformação Proteica em alfa-Hélice , Multimerização Proteica , RNA Bacteriano/química , Especificidade por Substrato
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