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1.
J Biol Chem ; 296: 100264, 2021 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-33837743

RESUMO

Recent studies have demonstrated that embryonic stem cells (ESCs) are deficient in expressing type I interferons (IFN), the cytokines that play key roles in antiviral responses. However, the underlying molecular mechanisms and biological implications of this finding are poorly understood. In this study, we developed a synthetic RNA-based assay that can simultaneously assess multiple forms of antiviral responses. Dicer is an enzyme essential for RNA interference (RNAi), which is used as a major antiviral mechanism in invertebrates. RNAi activity is detected in wild-type ESCs but is abolished in Dicer knockout ESCs (D-/-ESCs) as expected. Surprisingly, D-/-ESCs have gained the ability to express IFN, which is otherwise deficient in wild-type ESCs. Furthermore, D-/-ESCs have constitutively active double-stranded RNA (dsRNA)-activated protein kinase (PKR), an enzyme that is also involved in antiviral response. D-/-ESCs show increased sensitivity to the cytotoxicity resulting from RNA transfection. The effects of dsRNA can be partly replicated with a synthetic B2RNA corresponding to the retrotransposon B2 short interspersed nuclear element. B2RNA has secondary structure features of dsRNA and accumulates in D-/-ESCs, suggesting that B2RNA could be a cellular RNA that activates PKR and contributes to the decreased cell proliferation and viability of D-/-ESCs. Treatment of D-/-ESCs with a PKR inhibitor and IFNß-neutralizing antibodies increased cell proliferation rate and cell viability. Based on these findings, we propose that, in ESCs, Dicer acts as a repressor of antiviral responses and plays a key role in the maintenance of proliferation, viability, and pluripotency of ESCs.

2.
BMC Musculoskelet Disord ; 22(1): 328, 2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33810786

RESUMO

BACKGROUND: Limited studies were available to investigate the prevalence of deep vein thrombosis (DVT) on admission in elderly patients with intertrochanteric fractures. The aim of present study was to evaluate risk factors and the prevalence of pre-admission DVT in elderly patients with intertrochanteric fractures. METHODS: This retrospective study included 788 elderly patients with intertrochanteric fracture who were eligible for this study from January 1, 2010, to December 31, 2019. Color doppler ultrasonography was performed for DVT detection at admission. All patients' clinical data were collected. Univariate analysis and stepwise backward multivariate logistic regression were used to identify the risk factors contributing to the occurrence of DVT. RESULTS: The overall prevalence of pre-admission DVT in patients with intertrochanteric fractures was 20.81% (164 of 788 patients). The mean time from injury to admission was 2.1 days in the total population, 2.96 and 1.87 days in patients with and without DVT. Univariate analysis showed that significantly elevated risk of DVT were found in patients with longer time from injury to admission, high energy injury, lower Hb value, higher BMI, diabetes, chronic obstructive pulmonary disease (COPD), atrial fibrillation, dementia, varicose veins, higher age-adjusted CCI, higher ASA class and A3 type intertrochanteric fractures (P < 0.05). The adjusted multivariate logistic regression analysis demonstrated that longer time from injury to admission, high energy trauma, COPD, lower Hb, diabetes and A3 type intertrochanteric fractures were independent risk factors of pre-admission DVT. CONCLUSIONS: A high prevalence of pre-admission DVT was found in elderly Chinese patients with intertrochanteric fractures. Therefore, surgeons should be aware of the high prevalence of DVT for elderly patients with intertrochanteric fractures in order to prevent intraoperative and postoperative PE and other lethal complications.

3.
J Hematol Oncol ; 14(1): 57, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33827629

RESUMO

Ubiquitin-conjugating enzyme E2 M (UBE2M) and ubiquitin-conjugating enzyme E2 F (UBE2F) are the two NEDD8-conjugating enzymes of the neddylation pathway that take part in posttranslational modification and change the activity of target proteins. The activity of E2 enzymes requires both a 26-residue N-terminal docking peptide and a conserved E2 catalytic core domain, which is the basis for the transfer of neural precursor cell-expressed developmentally downregulated 8 (NEDD8). By recruiting E3 ligases and targeting cullin and non-cullin substrates, UBE2M and UBE2F play diverse biological roles. Currently, there are several inhibitors that target the UBE2M-defective in cullin neddylation protein 1 (DCN1) interaction to treat cancer. As described above, this review provides insights into the mechanism of UBE2M and UBE2F and emphasizes these two E2 enzymes as appealing therapeutic targets for the treatment of cancers.

4.
PLoS Pathog ; 17(4): e1009501, 2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33836016

RESUMO

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein mediates infection of cells expressing angiotensin-converting enzyme 2 (ACE2). ACE2 is also the viral receptor of SARS-CoV (SARS-CoV-1), a related coronavirus that emerged in 2002-2003. Horseshoe bats (genus Rhinolophus) are presumed to be the original reservoir of both viruses, and a SARS-like coronavirus, RaTG13, closely related to SARS-CoV-2, has been identified in one horseshoe-bat species. Here we characterize the ability of the S-protein receptor-binding domains (RBDs) of SARS-CoV-1, SARS-CoV-2, pangolin coronavirus (PgCoV), RaTG13, and LyRa11, a bat virus similar to SARS-CoV-1, to bind a range of ACE2 orthologs. We observed that the PgCoV RBD bound human ACE2 at least as efficiently as the SARS-CoV-2 RBD, and that both RBDs bound pangolin ACE2 efficiently. We also observed a high level of variability in binding to closely related horseshoe-bat ACE2 orthologs consistent with the heterogeneity of their RBD-binding regions. However five consensus horseshoe-bat ACE2 residues enhanced ACE2 binding to the SARS-CoV-2 RBD and neutralization of SARS-CoV-2 pseudoviruses by an enzymatically inactive immunoadhesin form of human ACE2 (hACE2-NN-Fc). Two of these mutations impaired neutralization of SARS-CoV-1 pseudoviruses. An hACE2-NN-Fc variant bearing all five mutations neutralized both SARS-CoV-2 pseudovirus and infectious virus more efficiently than wild-type hACE2-NN-Fc. These data suggest that SARS-CoV-1 and -2 originate from distinct bat species, and identify a more potently neutralizing form of soluble ACE2.

5.
FASEB J ; 35(5): e21534, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33817830

RESUMO

The adipocyte precursors (APs) located in white adipose tissue (WAT) are functionally significant in adipose plasticity and browning. Modifying adipogenesis or WAT browning targeted on APs is a promising mechanism for anti-obesity drug. We herein explored the in vitro actions and mechanisms of glucose-dependent insulinotropic polypeptide (GIP), a gut-derived peptide, in human adipose-derived mesenchymal stem cells (hADSCs) isolated from omentum. The hADSCs were cotreated with 100 nM GIP with or without equimolar concentration of GIP3-42 (a GIP receptor antagonist), and subsequently examined in vitro. CCK-8, EdU incorporation, and flow cytometry assays were used to assess cellular proliferation. Annexin V FTIC/PI double stain, TUNEL staining, and Western blot were applied for apoptosis evaluation. Adipogenesis was reflected by Western blot, real-time PCR, Oil Red O staining, mitochondrial staining, and mitochondrial DNA analysis. Results showed that GIP promoted proliferation and inhibited apoptosis of hADSCs via pleiotropic effects. Besides, GIP facilitated de novo beige adipogenesis, by accelerating mitotic clonal expansion (MCE), upregulating core adipogenic regulators (C/EBPα and PPARγ), augmenting beige-related genes (UCP1, PGC1α, and PRDM16), increasing mitochondrial content and improving beige adipocyte functionalities. Above all, our study expands knowledge on the mechanisms of GIP modifying adipogenesis especially in inducing beige adipogenesis, and thus provides a theoretical support for clinical usage of GIP on obesity treatment.

6.
J Med Internet Res ; 2021 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-33822735

RESUMO

BACKGROUND: During COVID-19 response, non-clinical essential workers usually work overtime and face strong work stress, which will subsequently increase risk of dying from cardiovascular diseases, stroke, and pre-existing conditions. Deaths on duty, including overwork deaths, during the COVID-19 response, were usually reported online for public recognition and solidarity. Though no official statistics is collecting those causalities, an online list of on-duty deaths has been made publicly available by crowdsourcing. OBJECTIVE: This study aims to understand the trends and characteristics of the overwork deaths among the frontline non-clinical essential workers participating in non-pharmaceutical interventions during the first wave of COVID-19 in China. METHODS: Based on an online crowdsourced list of deaths on duty during the first wave of COVID-19 response in China, we manually verified the overwork death records with the full text of the online reports from credible sources. After excluding deaths caused by COVID-19 infections and accidents, 340 overwork deaths among non-clinical essential were attributed to combatting COVID-19. We coded the key characteristics of deceased workers including sex, age at death, location, causes of death, date of incidence et cetera. The temporal and spatial correlations between overwork deaths and COVID-19 cases in China were also examined using Pearson correlation coefficient. RESULTS: From January 20 to April 26, at least 340 non-clinical frontline workers in China were documented to have died from overwork when combatting COVID-19. The weekly overwork mortality was positively correlated with weekly COVID-19 infections (r=0.79, p=< .001). Two-thirds of deceased workers were under 55 years old. Two major causes of overwork deaths were cardiovascular diseases (40.6%), and cerebrovascular diseases (21.5%). Outside of Hubei there were almost 2.5 times as many deaths caused by COVID-19 related overwork (n=308) than by the disease itself (n=120). CONCLUSIONS: The high number of overwork deaths among non-clinical essential workers on the front lines of the COVID-19 epidemic is alarming. Policies of occupational health protection against work hazards should be prioritized and enforced.

7.
Metabolites ; 11(2)2021 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33672315

RESUMO

Chronic renal failure (CRF) is an irreversible deterioration of the renal functions that characterized by fluid electrolyte unbalance and metabolic-endocrine dysfunctions. Increasing evidence demonstrated that metabolic disturbances, especially dyslipidemia and profound changes in lipid and lipoprotein metabolism were involved in CRF. Identification of lipids associated with impaired kidney functions may play important roles in the understanding of biochemical mechanism and CRF treatment. Ultra-performance liquid chromatography coupled with high-definition mass spectrometry-based lipidomics was performed to identify important differential lipids in adenine-induced CRF rats and investigate the undergoing anti-fibrotic mechanism of Polyporus umbellatus (PPU) and ergone (ERG). Linear correlation analysis was performed between lipid species intensities and creatinine levels in serum. Adenine-induced rats exhibited declining kidney function and renal fibrosis. Compared with control rats, a panel of lipid species was identified in the serum of CRF rats. Our further study demonstrated that eight lipids, including leukotrienes and bile acids, presented a strong linear correlation with serum creatinine levels. In addition, receiver operating characteristics analysis showed that eight lipids exhibited excellent area under the curve for differentiating CRF from control rats, with high sensitivity and specificity. The aberrant changes of clinical biochemistry data and dysregulation of eight lipids could be significantly improved by the administration of PPU and ergone. In conclusion, CRF might be associated with the disturbance of leukotriene metabolism, bile acid metabolism and lysophospholipid metabolism. The levels of eicosanoids and bile acids could be used for indicating kidney function impairment in CRF. PPU could improve renal functions and either fully or partially reversed the levels of eicosanoids and bile acids.

8.
Brain Behav ; 11(4): e02048, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33704916

RESUMO

OBJECTIVE: To identify circular RNAs as candidates for differential expression in the middle temporal (MT) cortex in a well-characterized cohort with contrasting Alzheimer disease (AD) pathology and cognition. Top screen candidates were assessed for proof of circularity and then quantified by qPCR in a larger number of samples. METHODS: An initial RNA sequencing screen was performed on n = 20 frozen human tissue samples. Filters were applied to select candidate circular RNAs for further investigation. Frozen human tissue samples were selected for global AD pathology burden and global cognition scores (n = 100). Linear and divergent primers were used to assess circularity using RNaseR digestion. RT-qPCR was performed to quantify relative hsa_circ_0131235 abundance. RESULTS: Eleven circular RNAs were selected for further investigation. Four candidates produced circular RNA primers with appropriate efficiencies for qPCR. RNaseR treatment and analysis by both basic PCR and qPCR confirmed hsa_circ_0131235 circularity. There was a significant main effect of AD pathology on hsa_circ_0131235 expression. CONCLUSIONS: Elevated hsa_circ_0131235 expression in the MT cortex was significantly associated with AD pathology.

9.
BMC Med Genomics ; 14(1): 73, 2021 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-33750369

RESUMO

BACKGROUND: The causality between the use of alcohol and cigarettes and atrial fibrillation (AF) remains controversial. We conducted a Mendelian randomization (MR) study to evaluate the association of genetic variants related to tobacco and alcohol use with AF. METHODS: Single nucleotide polymorphisms (SNPs) related to smoking initiation (N = 374), age at initiation of regular smoking (N = 10), cigarettes per day (N = 55), and smoking cessation (N = 24) were derived from a genome-wide association studies (GWAS) of tobacco use (N = 1.2 million individuals). SNPs related to heavy alcohol use (N = 6) were derived from a GWAS of UK biobank (N = 125,249 individuals). The genetically matching instrumented variables were obtained from the GWAS of AF (N = 588,190 individuals). The estimates between tobacco and alcohol use and AF were combined by inverse-variance weighted (IVW), simple median, weighted median, MR-robust adjusted profile score method, MR-PRESSO, and multivariable MR. RESULTS: A total of 65,446 AF patients and 522,744 referents were included. In the IVW analysis, the odds ratio per one-unit increase of smoking initiation was 1.11 (95% CI, 1.06-1.16; P = 3.35 × 10-6) for AF. Genetically predicted age at initiation of regular smoking, cigarettes per day and smoking cessation were not associated with AF. The IVW estimate showed that heavy alcohol consumption increased AF risk (OR, 1.11; 95% CI, 1.04-1.18; P = 0.001). The results were consistent in complementary analyses and multivariable MR. CONCLUSION: Our MR study indicated that regular smoking was associated with increased risk of AF, no matter the age at initiation of regular smoking, or the number of cigarettes smoked per day. Genetically predicted heavy alcohol consumption increased the risk of AF.

10.
Ying Yong Sheng Tai Xue Bao ; 32(3): 810-818, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33754545

RESUMO

To investigate the plant community characteristics of alpine cutting blanks under different restoration approaches, we conducted a field survey on cutting blanks experienced either natural restoration (40 years) or artificial restoration (30, 40 and 50 years) in western Sichuan, with natural forests as the reference. Our results showed that after 40 years natural succession, cutting blank was replaced by the secondary shrub of Spiraea alpina, while artificial restoration plantation was dominated by Picea likiangensis var. rubescens. The similarity indices between these communities and natural forests were low (0.19) and medium (0.28-0.49), respectively. Cutting blank through natural and artificial restoration had lower species diversity in the shrub layer but higher diversity in the herb layer than that of natural forests. With the increases of recovery time, total cross-sectional area at breast height, wood volume, index of species diameter class distribution, diversity indices, and similarity indices between plantations and natural forests gradually increased, while stand density gradually decreased. Compared with natural forests, plantations were facing with problems including high stand density, unreasonable structure, pure stands of cohorts and poor regeneration.


Assuntos
Florestas , Picea , Biodiversidade , China , Ecossistema
11.
Clin Spine Surg ; 2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33769977

RESUMO

STUDY DESIGN: A retrospective single-center study. OBJECTIVE: We aimed to compare the clinical outcomes of cervical spine fracture accompanied with ankylosing spondylitis (ASCSF) treated by single posterior approach (PA) and combined anterior-posterior approach (CA) for patients who were followed up for >1 year. SUMMARY OF BACKGROUND DATA: For ASCSF patients, surgical treatment has been widely accepted as a recommendable therapeutic option. But the optimal surgical approach is still under controversy, and few studies have focused on the comparison between PA and CA. MATERIALS AND METHODS: From February 2007 to March 2019, 53 patients were enrolled and divided into the PA group (34 cases) and CA group (19 cases). Their general characteristics and clinical materials were recorded. From the aspects of reduction distance, bone fusion, neurological functional restoration, and postoperative complications, patients' surgical outcomes were evaluated qualitatively and quantitatively. RESULTS: The reduction degree of dislocation (mean PA=2.05 mm, mean CA=2.36 mm, P=0.94) was close between the 2 groups. Besides, with a similar follow-up period (P=0.10), the rate of bone fusion (both 100%) and neurological functional restoration (PA=31.03%, CA=35.29%, P=0.77) were also without significant difference. The occurrence rate of postoperative complications tended to be higher in the CA group (31.58% vs. 23.53%) but with no significant difference (P=0.52). Nevertheless, the surgical duration time (mean=209.15 min) and blood loss (average=388.91 mL) of PA group were significantly less than CA group (mean duration time=285.34 min, mean blood loss=579.27 mL) (P<0.01). CONCLUSIONS: Compared with to the CA approach and with the equally significant outcome, surgery by single PA was feasible and should be positively recommended for ASCSF patients, especially for those accompanying with a severe chin-on-chest deformity or poor physical conditions which restrain patients from tolerating a long surgery or major surgical trauma.

12.
Artigo em Inglês | MEDLINE | ID: mdl-33783080

RESUMO

An approach to the highly efficient synthesis of C(sp3)-bridged [6]cycloparaphenylenes (C[6]CPPs) from fluoren[3]arenes (F[3]As) was developed. Consequently, F[3]As as a new kind of macrocyclic arenes were synthesized. Followed by the demethylation, triflation and intramolecular aryl-aryl coupling reactions, C[6]CPPs were then conveniently obtained. Interestingly, C[6]CPPs could be selectively methylated to produce their fully outer-methyl-substituted derivatives. The crystal structures showed the hydroxyl-substituted F[3]As had bowl-shaped conformations, and the C[6]CPPs exhibited rigid belt-shaped structures with deep cavities. Moreover, C[6]CPPs exhibited high HOMO energies and narrow energy gaps. An unclosed belt was further obtained, and it not only showed a similar narrow energy gap to those of the aromatic belts, but also displayed strong fluorescence property, which can play a vital role in the design and synthesis of new aromatic belts.

13.
J Cell Biochem ; 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33690923

RESUMO

Solute Carrier Family 6 Member 15 (SLC6A15), a sodium-dependent neutral amino acid transporter, has been found with dysregulated expression in several kinds of cancers. However, the expression pattern and the biological functions of SLC6A15 in papillary thyroid cancer (PTC) remain unknown. In this study, we found that SLC6A15 was downregulated in PTC, which was related to N classification. Ectopic overexpression of SLC6A15 impaired migratory and invasive abilities of PTC cell in vitro. In addition, we identified intercellular adhesion molecule-1, a vital oncogene in thyroid cancer progression, was involved in the effects of SLC6A15 on PTC cell. These results indicate that SLC6A15 acts as a tumor suppressor and might be a potential therapeutic target in the treatment of PTC.

14.
Artigo em Inglês | MEDLINE | ID: mdl-33651638

RESUMO

Objective: To investigate the efficacy and safety of cold snare endoscopic mucosal resection (CS-EMR) and hot snare endoscopic mucosal resection (HS-EMR) for colorectal polyps with diameters of 6-9 mm. Methods: Retrospective analysis was performed on the clinical data of 485 patients with colorectal polyps (6-9 mm in size) who were treated with CS-EMR or HS-EMR in the endoscopy center of Hangzhou Third People's Hospital from January 2017 to December 2019. Colorectal polyps were lifted by submucosal injection of normal saline. The CS-EMR group used a cold snare to remove the lifting polyps, while the HS-EMR group used a hot snare. Propensity score matching analysis with 1:1 matching and the nearest neighbor matching method were performed to ensure well-balanced characteristics of the CS-EMR and HS-EMR groups. Matching factors included age, gender, body mass index, blood routine, coagulation indicators, polyp site, size, number, and morphology. This resulted in a balanced cohort of 128 patients per group. Polyp recovery, complications, clipping for disclosure, and length of hospital stay were compared after matching. t-Tests, χ2 tests, McNemar's tests, and Fisher's exact test were used for comparison between the two groups before and after matching. Results: There were no differences between the two groups of intraoperative and postoperative bleeding (P > .05), but the CS-EMR clipping rate was lower than the HS-EMR group (P < .01). There was a higher incidence of post-polypectomy syndrome (PPS) (P = .03) and longer hospital stays (P < .01) in the HS-EMR group than the CS-EMR group. Conclusions: Compared with HS-EMR, CS-EMR is more convenient to operate, with a low incidence of PPS, clipping rates, and short hospital stays. It is a safe and effective removal method for 6-9 mm colorectal polyps.

15.
Artigo em Inglês | MEDLINE | ID: mdl-33650052

RESUMO

Evidence on the short-term effects of ambient air pollution on chronic obstructive pulmonary disease (COPD) mortality is still not conclusive. The aim of this study was to investigate the relationships between them in Wuhan China. Daily death numbers, concentrations of air pollutants (PM2.5, PM10, SO2, NO2, and O3), and meteorological characteristics in Wuhan from January 1, 2014, to December 31, 2019, were collected. Time-series analysis using generalized additive model was applied. The results showed that a total of 16,150 deaths (7.37 deaths per day) from COPD were observed. The daily average concentrations of PM2.5, PM10, SO2, NO2, and O3 were 59.03, 90.48, 12.91, 48.84, and 91.77 µg/m3, respectively. In single pollutant model, for every increase of 10 µg/m3 in PM10, SO2, and NO2 levels, COPD mortality increased by 0.583% (95% CI: 0.055-1.113%), 4.299% (95% CI: 0.978-7.729%), and 1.816% (95% CI: 0.515-3.313%) at lag03, respectively. No significant associations were found for PM2.5 and O3. Subgroup analysis demonstrated that females were more susceptible to PM2.5, PM10, SO2, and NO2. The concentrations of PM10, SO2, and NO2 were significantly associated with COPD mortality for older adults. The effects of PM2.5 and O3 on COPD mortality were higher in warm period. In two-pollutant models, the significantly positive associations between SO2 and NO2 and COPD mortality remained after adjusting for PM2.5 or O3. In conclusions, short-term exposure to PM10, SO2, and NO2 are significantly associated with a higher risk of COPD mortality. Female or elderly are more susceptible to air pollution. It is urgent to implement the environmental protection policy.

16.
Nat Protoc ; 2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33731963

RESUMO

UV radiation may lead to melanoma and nonmelanoma skin cancers by causing helix-distorting DNA damage such as cyclobutane pyrimidine dimers (CPDs). These DNA lesions, if located in important genes and not repaired promptly, are mutagenic and may eventually result in carcinogenesis. Examining CPD formation and repair processes across the genome can shed light on the mutagenesis mechanisms associated with UV damage in relevant cancers. We recently developed CPD-Seq, a high-throughput and single-nucleotide resolution sequencing technique that can specifically capture UV-induced CPD lesions across the genome. This novel technique has been increasingly used in studies of UV damage and can be adapted to sequence other clinically relevant DNA lesions. Although the library preparation protocol has been established, a systematic protocol to analyze CPD-Seq data has not been described yet. To streamline the various general or specific analysis steps, we developed a protocol named CPDSeqer to assist researchers with CPD-Seq data processing. CPDSeqer can accommodate both a single- and multiple-sample experimental design, and it allows both genome-wide analyses and regional scrutiny (such as of suspected UV damage hotspots). The runtime of CPDSeqer scales with raw data size and takes roughly 4 h per sample with the possibility of acceleration by parallel computing. Various guiding graphics are generated to help diagnose the performance of the experiment and inform regional enrichment of CPD formation. UV damage comparison analyses are set forth in three analysis scenarios, and the resulting HTML pages report damage directional trends and statistical significance. CPDSeqer can be accessed at https://github.com/shengqh/cpdseqer .

17.
Artigo em Inglês | MEDLINE | ID: mdl-33682300

RESUMO

Serotonin N-acetyltransferase (SNAT) is the key rate-limiting enzyme in melatonin biosynthesis. It mediates melatonin biosynthesis in plants by using serotonin and 5-methoxytryptamine (5-MT), but little is known of its underlying mechanisms. Herein, we present a detailed reaction mechanism of a SNAT from Oryza sativa through combined structural and molecular dynamics (MD) analysis. We report the crystal structures of plant SNAT in the apo and binary/ternary complex forms with acetyl-CoA (AcCoA), serotonin, and 5-MT. OsSNAT exhibits a unique enzymatically active dimeric fold not found in the known structures of arylalkylamine N-acetyltransferase (AANAT) family. The key residues W188, D189, D226, N220, and Y233 located around the active pocket are important in catalysis, confirmed by site-directed mutagenesis. Combined with MD simulations, we hypothesize a novel plausible catalytic mechanism in which D226 and Y233 function as catalytic base and acid during the acetyl-transfer reaction.

18.
Arch Insect Biochem Physiol ; 106(4): e21772, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33719088

RESUMO

The ß-adrenergic-like octopamine receptor (OA2B2), which binds the biogenic amine octopamine, belongs to the class of G-protein coupled receptors and significantly regulates many physiological and behavioral processes in insects. In this study, the putative open reading frame sequence of the MsOA2B2 gene in Mythimna separata was cloned, the full-length complementary DNA was 1191 bp and it encoded a 396-amino acid protein (GenBank accession number MN822800). Orthologous sequence alignment, phylogenetic tree analysis, and protein sequence analysis all showed that the cloned receptor belongs to the OA2B2 protein family. Real-time quantitative polymerase chain reaction of spatial and temporal expression analysis revealed that the MsOAB2 gene was expressed in all developmental stages of M. separata and was most abundant in egg stages and second and fourth instars compared with other developmental stages, while the expression level during the pupal stage was much lower than that at the other stages. Further analysis with sixth instar M. separata larvae showed that the MsOA2B2 gene was expressed 1.81 times higher in the head than in integument and gut tissues. Dietary ingestion of dsMsOA2B2 significantly reduced the messenger RNA level of MsOA2B2 and decreased mortality following amitraz treatment. This study provides both a pharmacological characterization and the gene expression patterns of OA2B2 in M. separata, facilitating further research for insecticides using MsOA2B2 as a target.


Assuntos
Mariposas/genética , Receptores de Amina Biogênica , Animais , Expressão Gênica/efeitos dos fármacos , Genes de Insetos , Controle de Insetos , Proteínas de Insetos/química , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Inseticidas/farmacologia , Larva/genética , Larva/metabolismo , Mariposas/metabolismo , Filogenia , Pupa/genética , Pupa/metabolismo , Receptores Adrenérgicos beta/química , Receptores Adrenérgicos beta/efeitos dos fármacos , Receptores Adrenérgicos beta/genética , Receptores Adrenérgicos beta/metabolismo , Receptores de Amina Biogênica/química , Receptores de Amina Biogênica/efeitos dos fármacos , Receptores de Amina Biogênica/genética , Receptores de Amina Biogênica/metabolismo , Toluidinas/farmacologia
19.
Cell Death Dis ; 12(3): 278, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33723262

RESUMO

Hepatocellular carcinoma (HCC) is one of the most common cancers with an insidious onset, strong invasiveness, insensitivity to chemotherapy, and poor prognosis, thus makes clinical treatment challenging. The mechanisms require further elucidation for developing novel therapies and targeting drug resistance. Here, we observed high Shc3 expression in patients with chemoresistant and recurrent HCCs. Shc3 overexpression induced a significant increase in MDR1/P-glycoprotein expression, whereas Shc3 knockdown impaired this expression. Further, Shc3 inhibition significantly restored HCC cell sensitivity to doxorubicin and sorafenib. Mechanistically, Shc3 interacted with ß-catenin, inhibited destruction complex stability, promoted ß-catenin release, and dampened ß-catenin ubiquitination. Shc3 bound ß-catenin and facilitated its nuclear translocation, prompting the ß-catenin/TCF pathway to elevate MDR1 transcription. ß-catenin blockage abolished the discrepancy in drug resistance between Shc3-depleted HCC cells and control cells, which further validating that ß-catenin is required for Shc3-mediated liver chemotherapy. We also determined the effect of Shc3 on the sensitivity of HCC to chemotherapy in vivo. Collectively, this study provides a potential strategy to target these pathways concurrently with systemic chemotherapy that can improve the clinical treatment of HCC.

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