Objective:To investigate the value of N-terminal pro B-type natriuretic peptide(NT-proBNP),high-sensitivity C-reactive protein(hs-CRP),and homocysteine(Hcy)levels in predicting cardiovascular events(CV)in patients wit...Objective:To investigate the value of N-terminal pro B-type natriuretic peptide(NT-proBNP),high-sensitivity C-reactive protein(hs-CRP),and homocysteine(Hcy)levels in predicting cardiovascular events(CV)in patients with chronic heart failure(CHF).Methods:A total of 63 patients with CHF admitted to our hospital between June 2019 and July 2021 were selected.Their NT-proBNP,hs-CRP,and Hcy levels were detected at discharge,and a 12-month follow-up was done after their discharge to collect clinical data.The collected data were inclusive of data from 21 CHF patients with cardiovascular disease and 42 CHF patients without cardiovascular disease.The effect of NT-proBNP,hs-CRP,and Hcy levels on the occurrence of CV was analyzed.Results:The levels of NT-proBNP,hs-CRP,and Hcy in the group with cardiovascular disease were significantly higher than those in the group without cardiovascular disease(P<0.05);the levels of serum NT-proBNP,hs-CRP,and Hcy at discharge had certain value in predicting short-term CV in CHF patients(P<0.05).Conclusion:NT-proBNP,hs-CRP,and Hcy levels can be used to predict CV in CHF patients,thus having clinical application value.展开更多
Following acute and chronic liver injury,hepatic stellate cells (HSCs) become activated to undergo a phenotypic transformation into myofibroblast-like cells and lose their retinol content,but the mechanisms of retinoi...Following acute and chronic liver injury,hepatic stellate cells (HSCs) become activated to undergo a phenotypic transformation into myofibroblast-like cells and lose their retinol content,but the mechanisms of retinoid loss and its potential roles in HSCs activation and liver fibrosis are not understood.The influence of retinoids on HSCs and hepatic fibrosis remains controversial.The purpose of this study was to evaluate the effects of all-trans retinoid acid (ATRA) on cell proliferation,mRNA expression of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)],profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),fibrolytic genes (MMP-3,MMP-13) and the upstream element (JNK and AP-1) in the rat hepatic stellate cell line (CFSC-2G).Cell proliferation was evaluated by measuring BrdU incorporation.The mRNA expression levels of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)],profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and fibrolytic genes (MMP-3,MMP-13) were quantitatively detected by using real-time PCR.The mRNA expression of JNK and AP-1 was quantified by RT-PCR.The results showed that ATRA inhibited HSCs proliferation and diminished the mRNA expression of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)] and profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and significantly stimulated the mRNA expression of MMP-3 and MMP-13 in HSCs by suppressing the mRNA expression of JNK and AP-1.These findings suggested that ATRA could inhibit proliferation and collagen production of HSCs via the suppression of active protein-1 and c-Jun N-terminal kinase signal,then decrease the mRNAs expression of profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and significantly induce the mRNA expression of MMP-3 and MMP-13.展开更多
Objective:To investigate the effect of atorvastatin on serum oxidative stress and N-terminal brain natriuretic peptide expression in rats.Methods:A total of 40 healthy male SD rats were randomly divided into the sham ...Objective:To investigate the effect of atorvastatin on serum oxidative stress and N-terminal brain natriuretic peptide expression in rats.Methods:A total of 40 healthy male SD rats were randomly divided into the sham group(Croup A,n=10,saline 5 mL/d),ischemia-reperfusion group(Group B,n=10,saline S mL/d),atorvastatin group(Group C,n=10.atorvastatin 20 mg/kg·d),atorvastatin + N-amino-arginine group(Group D,n=10,atorvastatin 20 mg/kg·d + N-amino arginine 15 mg/kg).Myocardial ischemia-reperfusion rat model was eslablished after 3 days of gavage.N-amino arginine 15 mg/kg was given by tail vein injection 15 min before ischemia.After reperfusion,enzymology indicators such us creatine kinase(CK) and lactate dehydrogenase and the oxidative stress parameters such as nitric oxide(NO),malondialdehyde(MDA) and total superoxide dismutase(TSOD),and n-terminal pro-brain natriuretic peptide(NT-proBNP)expression was detected by immunohistochemistry.Results:LDH and CK levels of group A were significantly lower than the outer three groups,and group B was the highest.There was significant difference between group B and group C(P<0.05),and no significant difference between group B and group D(P>0.05).MDA levels in group B were significantly higher than the other three groups.The lowest was group A,followed by group C,the difference among groups was significantly(P<0.05).TSOD and NO levels in group B was the lowest,the level in group A was the highest,followed by group C,the difference among groups was significant(P<0.05).NT-proBNP level in group B was significantly higher than the other three groups,the lowest was group A,followed by group C,the difference among groups was significant(P<0.05).Conclusions:Atorvastatin has a protective effect on the myocardial injury in the myocardial ischemia and reperfusion rats.It can increase NO synthesis and decrease MDA content,increase serum TSOD activity and the oxidative stress effect,meanwhile protect myocardial cells and reduce myocardial injury.展开更多
To investigate plasma N-terminal pro-brain natriuretic peptide (NT-BNP) levels and to assess their clinical significance in elderly patients with isolated diastolic dysfunction. Methods Plasma NT-BNP level were measur...To investigate plasma N-terminal pro-brain natriuretic peptide (NT-BNP) levels and to assess their clinical significance in elderly patients with isolated diastolic dysfunction. Methods Plasma NT-BNP level were measured by electrochemiluminescence immunoassay in 34 symptomatic patients (Group 1), 34 asymptomatic patients (Group 2) with isolated diastolic dysfunction, and in 16elderly healthy subjects (control group, Group 3), serving controls. Colored Doppler echocardiography was performed to evaluate the patients' cardiac structures and functions. Results The plasma NT-BNP level in Group 1 was significantly higher than those in Group 2 and Group 3 and increased with the severity of heart failure. There was no significant difference of plasma NT-BNP levels between Group 2 and Group 3 (p＞0.05). A NT-BNP value of 102.75 pg/mL showed a sensitivity of 88.2%, a specificity of 87.5%, and an accuracy of 88.1% for diagnosing diastolic dysfunction. Patients with restrictive filling pattern on echocardiography had higher NTBNP levels than those of impaired relaxation pattern (1961.2±304.9 versus 460. 1±92.7pg/mL, p＜0.001). Conclusion The elevation of plasma NT-BNP level in elderly patients with isolated diastolic dysfunction correlates with the severity of their diastolic abnormalities.The level of plasma NT-BNP has an important clinical value in the diagnosis of elderly patients with isolated diastolic dysfunction.展开更多
AIM: To clarify the relationship between autophagy and lipotoxicity-induced apoptosis, which is termed "lipoapoptosis," in non-alcoholic steatohepatitis. METHODS: Male C57BL/6J mice were fed a high-fat diet(...AIM: To clarify the relationship between autophagy and lipotoxicity-induced apoptosis, which is termed "lipoapoptosis," in non-alcoholic steatohepatitis. METHODS: Male C57BL/6J mice were fed a high-fat diet(HFD) for 12 wk, after which the liver histology and expression of proteins such as p62 or LC3 were evaluated. Alpha mouse liver 12(AML12) cells treated with palmitate(PA) were used as an in vitro model. RESULTS: LC3-Ⅱ, p62, and Run domain Beclin-1 interacting and cysteine-rich containing(Rubicon) proteins increased in both the HFD mice and in AML12 cells in response to PA treatment. Rubicon expression was decreased upon c-Jun N-terminal kinase(JNK) inhibition at both the m RNA and the protein level in AML12 cells. Rubicon knockdown in AML12 cells with PA decreased the protein levels of both LC3-Ⅱ and p62. Rubicon expression peaked at 4 h of PA treatment in AML12, and then decreased. Treatment with caspase-9 inhibitor ameliorated the decrease in Rubicon protein expression at 10 h of PA and resulted in enlarged AML12 cells under PA treatment. The enlargement of AML12 cells by PA with caspase-9 inhibition was canceled by Rubicon knockdown.CONCLUSION: The JNK-Rubicon axis enhanced lipoapoptosis, and caspase-9 inhibition and Rubicon had effects that were cytologically similar to hepatocyte ballooning. As ballooned hepatocytes secrete fibrogenic signals and thus might promote fibrosis in the liver, the inhibition of hepatocyte ballooning might provide antifibrosis in the NASH liver.展开更多
To investigate the roles of c-Jun N-terminal kinase (JNK)signaling pathway in vitamin E succinate-induced apoptosisin human gastric cancer SGC-7901 cells.
Our previous results indicated that both the secreted and the intracellular form of full length and 1-97 N-terminal fragment of IGFBP-3 induce apoptosis in PC-3 human prostate cancer cells in an IGF-dependent and inde...Our previous results indicated that both the secreted and the intracellular form of full length and 1-97 N-terminal fragment of IGFBP-3 induce apoptosis in PC-3 human prostate cancer cells in an IGF-dependent and independent manner. This study was undertaken to delineate possible down-stream signaling pathways that are involved in this process. Intact IGFBP-3 and its N-terminal 1-97 fragments with or without a signal propeptide were fused to YFP and expressed in PC-3 human prostate cancer cells. In some cases, the putative IGF-binding site was presented in full length IGFBP-3 and its N-terminal fragment was also mutated. Extent of apoptosis was quantified using FACS. Up-regulation of total Stat-1 and activation of phospho-Stat-1 were shown by western blot. TGF-β signal was measured by luciferase reporter assay. Results from inhibitor studies indicated that both the Caspase 8 and caspase 9 pathways are involved in IGFBP-3 (non-secreted form) which induced apoptosis in PC-3 cells. Exogenous addition of IGFBP-3 to PC-3 cells increased Stat-1 protein expression/tyrosine phosphorylation. Interestingly, results also showed that knockdown of Stat-1 by siRNA potentiated the IGFBP-3 induced apoptosis in PC-3 cells. In addition, both full-length IGFBP-3 and its 1-97 Nterminal fragments inhibited TGF-β signaling in these cells. This is the first report that compares the signal transduction pathways involved in apoptotic pathways mediated by IGFBP-3 in PC-3 human prostate cancer cells. Non-secreted form of full length IGFBP-3 and its N-terminal fragments induced apoptosis in PC-3 cells via activation of caspase 8 and caspase 9. Although, only non-secreted form of IGFBP-3 is involved in inducing apoptosis in PC-3 cells via caspase 8 and caspase 9 activation pathways but both secreted and non-secreted forms of IGFBP-3 are involved in modulating Stat-1 and TGF-β pathways to induce apoptotic actions in PC-3 cells. Non-secreted intact IGFBP-3 and its N-terminal fragments induced apoptosis in PC-3 cells via activation of caspase 8 and caspase 9 pathways. Modulation in STAT-1 and TGF-β pathways may also be important for IGFBP-3 induced apoptosis in PC-3 cells in general. These studies clearly demonstrate that secreted and non-secreted FL and 1-97 N-terminal fragments induce apoptosis in PC-3 cells by regulating different mechanistic pathways.展开更多
AIM: To illustrate the isoform-specific role and mechanism of c-Jun N-terminal kinases(JNKs) in mouse optic nerve axotomy induced neurotrauma. METHODS: We firstly investigated the expression of JNK1, JNK2, and JNK3 in...AIM: To illustrate the isoform-specific role and mechanism of c-Jun N-terminal kinases(JNKs) in mouse optic nerve axotomy induced neurotrauma. METHODS: We firstly investigated the expression of JNK1, JNK2, and JNK3 in the retinal ganglion cells(RGCs) by double-immunofluorescent staining. Then we created optic nerve axotomy model in wild type as well as JNK1, JNK2, JNK3, isoform specific gene deficiency mice. With that, we checked the protein expression profile of JNKs and its active form, and quantified the survival RGCs number by immunofluorescence staining. We further explored the molecules underlying isoform specific protective effect by real-time polymerase chain reaction(PCR) and Western blotting assay. RESULTS: We found that all the three isoforms of JNKs were expressed in the RGCs. Deficiency of JNK3, but not JNK1 or JNK2, significantly alleviated optic nerve axotomyinduced RGCs apoptosis. We further established that expression of Noxa, a pro-apoptotic member of BH3 family, was significantly suppressed only in JNK3 gene deficiency mice. But tumor necrosis factor receptor 1(TNFR1) and Fas, two key modulators of death receptor mediated apoptosis pathway, did not display obvious change in the expression. CONCLUSION: It is suggested that mitochondria mediated apoptosis, but not death receptor mediated apoptosis got involved in the JNK3 gene deficiency induced RGCs protection. Our study provides a novel insight into the isoform-specific role of JNKs in neurotrauma and indicates some cues for its therapeutics.展开更多
Background: Acute heart failure timely and effective diagnosis and treatment directly affects the prognosis of patients, so early diagnosis of acute heart failure treatment is very important. The current diagnosis of ...Background: Acute heart failure timely and effective diagnosis and treatment directly affects the prognosis of patients, so early diagnosis of acute heart failure treatment is very important. The current diagnosis of acute heart failure has yet to be further improved. To investigate the relationship between plasma levels of Galectin-3 and NT-proBNP in cardiac structure and function in patients with acute heart failure (AHF) Early detection of failure. Methods: The clinical data of 86 patients with acute heart failure in our hospital were analyzed and followed up. Twenty-six healthy subjects with normal cardiac function were used as control group. The plasma Galectin-3 and NT-proBNP levels were compared between the two groups to observe the value of plasma Galectin-3 combined with NT-proBNP in the diagnosis of acute heart failure. Results: There was no significant difference in the level of Galectin-3 and NT-proBNP between heart function group II and control group, and the levels of cardiac function III and IVG plasma Galectin-3 and NT-proBNP were significantly higher in patients with heart failure Compared with the healthy control group, the patients’ LVEF decreased and their cardiac function increased. The levels of plasma Galectin-3 and NT-proBNP increased significantly (P 0.01). Multivariate Logistic regression analysis demonstrated that plasma levels of Galectin-3 and NT-proBNP were independent of cardiac function. The area under the ROC curve for the combined detection of plasma Galectin-3 and NT-proBNP was greater than the area under the two alone tests. Conclusion: The combined detection of Galectin-3 and NT-proBNP has high sensitivity and specificity in the diagnosis of acute heart failure and can be used as a new detection mode.展开更多
Patients with pulmonary embolism (PE) have a high risk of death and it is important to recognize factors associated with high mortality. N-Terminal pro-Brain Natriuretic Peptide (NT-pro BNP) has recently emerged as a ...Patients with pulmonary embolism (PE) have a high risk of death and it is important to recognize factors associated with high mortality. N-Terminal pro-Brain Natriuretic Peptide (NT-pro BNP) has recently emerged as a promising biomarker for risk assessment in acute pulmonary embolism (PE). The aim of this study is to detect the in hospital prognostic value of NT-pro BNP in patients with acute (PE). Methods: This study included 64 patients diagnosed as (PE) with the mean age of 59.1 ± 16.5 years, 40 patients of them (62.5%) were male. All patients were subjected to 12 leads ECG. X-ray chest, laboratory tests including D-Dimer, troponin I, NT-pro BNP, Doppler ultrasound for the venous system of both lower limbs, Echocardiograhy and 64 multislices CT pulmonary angiography. Results: According to the admission level of NT-pro BNP our patients were divided into two groups: group I included 22 patients with normal NT-pro BNP (less than 300 pg/ml), and group II included 42 patients with elevated NT-pro BNP (more than or equal 300 pg/ml). Patients in group II were found to have a significantly higher incidence of heart failure (28.6% Vs 4.6%, p = 0.025), impaired kidney function (serum creatinine was 1.7 ± 0.6 Vs 1.1 ± 0.2, p = 0.018), tachypnea (85.7% Vs 54.5%, p = 0.006) and cardiogenic shock (26.2% Vs 0%, p = 0.014) but a significantly lower incidence of chest pain (21.4% Vs 45.5%, p = 0.04) and lower left ventricular ejection fraction (51.3% ± 16.9% Vs 67.3% ± 12.8%, p = 0.043) compared to group I. There were a significantly higher treatment with thrombolytic therapy (35.7% Vs 9.1%, p=0.021) and positive inotropics (35.71% Vs 4.55%, p = 0.006) in group II compared to group I. Also group II had a higher need for mechanical ventilation (26.12% Vs 4.55%, p = 0.04) and a longer in hospital stay (19.5 ± 10.3 Vs 5.3 ± 4.5, p = 0.001) than group I. The in hospital mortality was significantly higher in group II compared to group I (19.05% Vs 0.0%, p = 0.042). Conclusion: Elevated NT-pro BNP levels in patients with (PE) are associated with worse short term prognosis in terms of higher morbidity and mortality and it could be used as a valuable prognostic parameter and good indicator for the need of more aggressive therapy.展开更多
In order to establish the sequence dependence of RimJ-mediated protein N-terminal acetylation in E. coli, the Z-domain variants differing by the second or third amino acid residue were expressed and analyzed by mass s...In order to establish the sequence dependence of RimJ-mediated protein N-terminal acetylation in E. coli, the Z-domain variants differing by the second or third amino acid residue were expressed and analyzed by mass spectrometry. Only subsequent to the initiating methionine residue cleavage, the RimJ-catalyzed N-terminal acetylation mainly occurred at the N-terminal serine and threonine residues and was significantly enhanced by hydrophobic or negatively charged residues in the penultimate position.展开更多
Objective:To study the effect of milrinone on the cardiac function and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels in patients with senile refractory heart failure. Methods:90 patients with senile refr...Objective:To study the effect of milrinone on the cardiac function and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels in patients with senile refractory heart failure. Methods:90 patients with senile refractory heart failure who were treated in our hospital between August 2013 and August 2016 were collected and divided into control group (n=45) and observation group (n=45) according to the random number table. The control group received regular clinical treatment, and the observation group received regular + milrinone treatment. The cardiac function and serum NT-proBN contents were compared between two groups of patients before and after treatment.Results: Before treatment, the differences in ultrasound and serum cardiac function indexes and serum NT-proBN levels were not statistically significant between two groups of patients. After treatment, ultrasound serum cardiac function parameter LVEDD level in observation group was lower than that in control group while CI and SV levels were higher than those in control group;serum cardiac function indexes Cys-C, GDF-15, sST2 and H-FABP contents were lower than those in control group;serum NT-proBNP content was lower than that in control group.Conclusion: Milrinone therapy can optimize the cardiac function and reduce the serum NT-proBN levels in patients with senile refractory heart failure.展开更多
Numerous strategies for linking desired chemical probes with target peptides and proteins have been developed and applied in the field of biological chemistry.Approaches for site-specific modification of native amino ...Numerous strategies for linking desired chemical probes with target peptides and proteins have been developed and applied in the field of biological chemistry.Approaches for site-specific modification of native amino acid residues in test tubes and biological contexts represent novel biological tools for understanding the role of peptides and proteins.Selective N-terminal modification strategies have been broadly studied especially in the last 10 years,as N-terminal positions are typically solvent exposed and provide chemically distinct sites for many peptide and protein targets,making N terminus distinct from other functional groups.A growing number of chemical and enzymatic techniques have been developed to modify N-terminal amino acids,and those techniques have the potential in the fields of medicine,basic research and applied materials science.This review focuses on appraising modification methodologies with the potential for biological applications from the past 10 years.展开更多
Background:Clinical assessment and treatment guidance for heart failure depends on a variety of biomarkers.The objective of this study was to investigate the prognostic predictive value of growth differentiation facto...Background:Clinical assessment and treatment guidance for heart failure depends on a variety of biomarkers.The objective of this study was to investigate the prognostic predictive value of growth differentiation factor-15(GDF-15)and N-terminal prohormone of brain natriuretic peptide(NT-proBNP)in assessing hospitalized patients with acute heart failure(AHF).Methods:In total,260 patients who were admitted for AHF in the First Affiliated Hospital of Nanjing Medical University were enrolled from April 2012 to May 2016.Medical history and blood samples were collected within 24 h after the admission.The primary endpoint was the all-cause mortality within 1 year.The patients were divided into survival group and death group based on the endpoint.With established mortality risk factors and serum GDF-15 level,receiver-operator characteristic(ROC)analyses were performed.Cox regression analyses were used to further analyze the combination values of NT-proBNP and GDF-15.Results:Baseline GDF-15 and NT-proBNP were significantly higher amongst deceased than those in survivors(P<0.001).In ROC analyses,area under curve(AUC)for GDF-15 to predict 1-year mortality was 0.707(95%confidence interval[CI]:0.648–0.762,P<0.001),and for NT-proBNP was 0.682(95%CI:0.622–0.738,P<0.001).No statistically significant difference was found between the two markers(P=0.650).Based on the optimal cut-offs(GDF-15:4526.0 ng/L;NT-proBNP:1978.0 ng/L),the combination of GDF-15 and NT-proBNP increased AUC for 1-year mortality prediction(AUC=0.743,95%CI:0.685–0.795,P<0.001).Conclusions:GDF-15,as a prognostic marker in patients with AHF,is not inferior to NT-proBNP.Combining the two markers could provide an early recognition of high-risk patients and improve the prediction values of AHF long-term prognosis.Clinical trial registration:ChiCTR-ONC-12001944,http://www.chictr.org.cn.展开更多
The main protease(M^(pro))plays a vital role in proteolytic processing of the polyproteins in the replicative cycle of SARS coronavirus(SARS-CoV).Dimerization of this enzyme has been shown to be indispensable for tran...The main protease(M^(pro))plays a vital role in proteolytic processing of the polyproteins in the replicative cycle of SARS coronavirus(SARS-CoV).Dimerization of this enzyme has been shown to be indispensable for transcleavage activity.However,the auto-processing mechanism of M^(pro),i.e.its own release from the polyproteins through autocleavage,remains unclear.This study elucidates the relationship between the N-terminal autocleavage activity and the dimerization of“immature”M^(pro).Three residues(Arg4,Glu290,and Arg298),which contribute to the active dimer conformation of mature M^(pro),are selected for mutational analyses.Surprisingly,all three mutants still perform N-terminal autocleavage,while the dimerization of mature protease and transcleavage activity following auto-processing are completely inhibited by the E290R and R298E mutations and partially so by the R4E mutation.Furthermore,the mature E290R mutant can resume N-terminal autocleavage activity when mixed with the“immature”C145A/E290R double mutant whereas its trans-cleavage activity remains absent.Therefore,the N-terminal auto-processing of M^(pro) appears to require only two“immature”monomers approaching one another to form an“intermediate”dimer structure and does not strictly depend on the active dimer conformation existing in mature protease.In conclusion,an auto-release model of M^(pro) from the polyproteins is proposed,which will help understand the auto-processing mechanism and the difference between the autocleavage and trans-cleavage proteolytic activities of SARS-CoV M^(pro).展开更多
The NifA protein is the central regulator of the nitrogen fixation genes. It activates transcription of nif genes by an alternative holoenzyme form of RNA polymerase containing the σ54 factor. The NifA protein from K...The NifA protein is the central regulator of the nitrogen fixation genes. It activates transcription of nif genes by an alternative holoenzyme form of RNA polymerase containing the σ54 factor. The NifA protein from Klebsiella pneumoniae consists of the N-terminal domain of unknown function, the central catalytic domain with ATPase activity and the C-terminal DNA-binding domain. The Kp NifA protein is sensitive to temperature, while the Enterobacter cloacae NifA protein is less sensitive to temperature than Kp NifA. Our results show that the N-terminal domain of NifA plays the decisive role in the temperature sensitivity of the protein.展开更多
STAPHYLOCOCCAL nuclease(SNase A,EC 3.1.4.7),which hydrolyzes the phosphodiesterbond of DNA and RNA,and releases 3’-phosphate mononucleotides and dinucleotides,con-sists of 149 amino acid residues(MW=16 807)without su...STAPHYLOCOCCAL nuclease(SNase A,EC 3.1.4.7),which hydrolyzes the phosphodiesterbond of DNA and RNA,and releases 3’-phosphate mononucleotides and dinucleotides,con-sists of 149 amino acid residues(MW=16 807)without sulfhydryl and disulfide groups.SNase A was originally derived from Staphylococcus aureus.Later the gene of the enzyme wascloned and inserted into several expression systems.Its crystal structure was detected展开更多
N-terminal acetylation is one of the most common protein modifications in eukaryotes,and approximately 40%of human and plant proteomes are acetylated by ribosome-associated N-terminal acetyltransferase A(NatA)in a co-...N-terminal acetylation is one of the most common protein modifications in eukaryotes,and approximately 40%of human and plant proteomes are acetylated by ribosome-associated N-terminal acetyltransferase A(NatA)in a co-translational manner.However,the in vivo regulatory mechanism of NatA and the global impact of NatA-mediated N-terminal acetylation on protein fate remain unclear.Here,we identify Huntingtin Yeast partner K(HYPK),an evolutionarily conserved chaperone-like protein,as a positive regulator of NatA activity in rice.We found that loss of OsHYPK function leads to developmental defects in rice plant architecture but increased resistance to abiotic stresses,attributable to perturbation of the N-terminal acetylome and accelerated global protein turnover.Furthermore,we demonstrated that OsHYPK is also a substrate of NatA and that N-terminal acetylation of OsHYPK promotes its own degradation,probably through the Ac/N-degron pathway,which could be induced by abiotic stresses.Taken together,our findings suggest that the OsHYPK-NatA complex plays a critical role in coordinating plant development and stress responses by dynamically regulating NatA-mediated N-terminal acetylation and global protein turnover,which are essential for maintaining adaptive phenotypic plasticity in rice.展开更多
Lactate dehydrogenase A (LDHA) is a well-characterized tetrameric enzyme. Its N-terminal arm, comprised of an (-helix and a (-strand, was suggested to be essential for subunit interactions. To examine the critical ami...Lactate dehydrogenase A (LDHA) is a well-characterized tetrameric enzyme. Its N-terminal arm, comprised of an (-helix and a (-strand, was suggested to be essential for subunit interactions. To examine the critical amino acid residues in the N-terminus involved in the subunit association, two single-point mutants, Leu3Pro (L3P) and Ile8Glu (I8E), have been constructed. We compared the stability of WT-LDHA (WT) and its variants by unfolding experiments. For WT, a dimeric but inactive intermediate was observed by size-exclusion chromatography at 0.6-0.8 mol/L GdmCl. Leu3Pro exists in an active tetrameric structure in aqueous solution as WT does, but it dissociates into dimers under lower concentration of GdmCl (0.2 mol/L). In aqueous solution, the Ile8Glu variant exists predominantly in the dimeric form with increased KM and decreased kcat as compared with those of WT and L3P. However, the activity of Ile8Glu increases significantly in the presence of sodium sulfate. In conclusion, two mutants are less stable than WT in oligomer structure. Results also support the fact that some residues in the N-terminal arm, especially the Leu8 in the (-structure, contribute the important binding energies to the dimerization of dimers, which might affect the assembly of the enzyme as well as the catalytic function.展开更多
Objective:Early identification of acute kidney injury(AKI)is essential to improve the prognosis of patients with acute heart failure(AHF).We aimed to determine the utility of neutrophil/lymphocyte ratio(NLR),N-termina...Objective:Early identification of acute kidney injury(AKI)is essential to improve the prognosis of patients with acute heart failure(AHF).We aimed to determine the utility of neutrophil/lymphocyte ratio(NLR),N-terminal prohormone of brain natriuretic peptide(NT-proBNP),urea,and creatinine(Cr),as well as combinations of these,for the prediction of AKI in patients with AHF.Methods:A total of 153 patients with AHF under the care of Sun Yat-sen Memorial Hospital,Sun Yat-sen University from October 2009 to October 2019 were included in this retrospective observational study.Their NLR,NT-proBNP,urea,and Cr concentrations were measured on admission.AKI was defined using the Acute Kidney Injury Network criteria.Receiver operating characteristic(ROC)curves,the areas under the curves(AUCs),sensitivity,and specificity were employed to evaluate the ability of each biomarker and their combinations to identify AKI.This study was approved by the Ethics Committee of Sun Yat-sen Memorial Hospital,Sun Yat-sen University(approval No.SYSEC-KY-KS-2021-126)on June 22,2021.Results:Forty-six(30.1%)participants developed AKI during hospitalization.The NLR and NT-proBNP of the participants with AKI were higher than those without(NLR:median 7.886 vs 4.717,P<0.0001;NT-proBNP,median 6774 vs 2786pg/mL,P<0.0001).ROC analyses demonstrated that high NLR and NT-proBNP were associated with higher incidences of AKI(NLR:cut-off 5.681,AUC 0.716,sensitivity 58.9%,specificity 80.4%;NT-proBNP:cut-off 5320pg/mL,AUC 0.700,sensitivity 72.9%,specificity 65.2%).Moreover,a combination of NLR,NT-proBNP,urea,and Cr yielded an AUC of 0.815,sensitivity 80.4%,and specificity of 74.8%.In addition,the AUCs for the prediction of AKI in the participants with New York Heart Association(NYHA)classes II,III,and IV were 0.936,0.860,and 0.772,respectively,using this combination.Conclusion:A combination of NLR,NT-proBNP,urea,and Cr,measured at admission,may represent a promising tool for the prediction of AKI in patients with AHF.This method performs best for AKI risk assessment in patients with NYHA II,followed by those with NYHA III or IV.展开更多
基金supported by the Project of Baoding Science and Technology Bureau(Project number:2241ZF343).
文摘Objective:To investigate the value of N-terminal pro B-type natriuretic peptide(NT-proBNP),high-sensitivity C-reactive protein(hs-CRP),and homocysteine(Hcy)levels in predicting cardiovascular events(CV)in patients with chronic heart failure(CHF).Methods:A total of 63 patients with CHF admitted to our hospital between June 2019 and July 2021 were selected.Their NT-proBNP,hs-CRP,and Hcy levels were detected at discharge,and a 12-month follow-up was done after their discharge to collect clinical data.The collected data were inclusive of data from 21 CHF patients with cardiovascular disease and 42 CHF patients without cardiovascular disease.The effect of NT-proBNP,hs-CRP,and Hcy levels on the occurrence of CV was analyzed.Results:The levels of NT-proBNP,hs-CRP,and Hcy in the group with cardiovascular disease were significantly higher than those in the group without cardiovascular disease(P<0.05);the levels of serum NT-proBNP,hs-CRP,and Hcy at discharge had certain value in predicting short-term CV in CHF patients(P<0.05).Conclusion:NT-proBNP,hs-CRP,and Hcy levels can be used to predict CV in CHF patients,thus having clinical application value.
文摘Following acute and chronic liver injury,hepatic stellate cells (HSCs) become activated to undergo a phenotypic transformation into myofibroblast-like cells and lose their retinol content,but the mechanisms of retinoid loss and its potential roles in HSCs activation and liver fibrosis are not understood.The influence of retinoids on HSCs and hepatic fibrosis remains controversial.The purpose of this study was to evaluate the effects of all-trans retinoid acid (ATRA) on cell proliferation,mRNA expression of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)],profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),fibrolytic genes (MMP-3,MMP-13) and the upstream element (JNK and AP-1) in the rat hepatic stellate cell line (CFSC-2G).Cell proliferation was evaluated by measuring BrdU incorporation.The mRNA expression levels of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)],profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and fibrolytic genes (MMP-3,MMP-13) were quantitatively detected by using real-time PCR.The mRNA expression of JNK and AP-1 was quantified by RT-PCR.The results showed that ATRA inhibited HSCs proliferation and diminished the mRNA expression of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)] and profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and significantly stimulated the mRNA expression of MMP-3 and MMP-13 in HSCs by suppressing the mRNA expression of JNK and AP-1.These findings suggested that ATRA could inhibit proliferation and collagen production of HSCs via the suppression of active protein-1 and c-Jun N-terminal kinase signal,then decrease the mRNAs expression of profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and significantly induce the mRNA expression of MMP-3 and MMP-13.
基金supported by Science and Technology Department General Project in Hunan Province(2012SK3127)
文摘Objective:To investigate the effect of atorvastatin on serum oxidative stress and N-terminal brain natriuretic peptide expression in rats.Methods:A total of 40 healthy male SD rats were randomly divided into the sham group(Croup A,n=10,saline 5 mL/d),ischemia-reperfusion group(Group B,n=10,saline S mL/d),atorvastatin group(Group C,n=10.atorvastatin 20 mg/kg·d),atorvastatin + N-amino-arginine group(Group D,n=10,atorvastatin 20 mg/kg·d + N-amino arginine 15 mg/kg).Myocardial ischemia-reperfusion rat model was eslablished after 3 days of gavage.N-amino arginine 15 mg/kg was given by tail vein injection 15 min before ischemia.After reperfusion,enzymology indicators such us creatine kinase(CK) and lactate dehydrogenase and the oxidative stress parameters such as nitric oxide(NO),malondialdehyde(MDA) and total superoxide dismutase(TSOD),and n-terminal pro-brain natriuretic peptide(NT-proBNP)expression was detected by immunohistochemistry.Results:LDH and CK levels of group A were significantly lower than the outer three groups,and group B was the highest.There was significant difference between group B and group C(P<0.05),and no significant difference between group B and group D(P>0.05).MDA levels in group B were significantly higher than the other three groups.The lowest was group A,followed by group C,the difference among groups was significantly(P<0.05).TSOD and NO levels in group B was the lowest,the level in group A was the highest,followed by group C,the difference among groups was significant(P<0.05).NT-proBNP level in group B was significantly higher than the other three groups,the lowest was group A,followed by group C,the difference among groups was significant(P<0.05).Conclusions:Atorvastatin has a protective effect on the myocardial injury in the myocardial ischemia and reperfusion rats.It can increase NO synthesis and decrease MDA content,increase serum TSOD activity and the oxidative stress effect,meanwhile protect myocardial cells and reduce myocardial injury.
文摘To investigate plasma N-terminal pro-brain natriuretic peptide (NT-BNP) levels and to assess their clinical significance in elderly patients with isolated diastolic dysfunction. Methods Plasma NT-BNP level were measured by electrochemiluminescence immunoassay in 34 symptomatic patients (Group 1), 34 asymptomatic patients (Group 2) with isolated diastolic dysfunction, and in 16elderly healthy subjects (control group, Group 3), serving controls. Colored Doppler echocardiography was performed to evaluate the patients' cardiac structures and functions. Results The plasma NT-BNP level in Group 1 was significantly higher than those in Group 2 and Group 3 and increased with the severity of heart failure. There was no significant difference of plasma NT-BNP levels between Group 2 and Group 3 (p＞0.05). A NT-BNP value of 102.75 pg/mL showed a sensitivity of 88.2%, a specificity of 87.5%, and an accuracy of 88.1% for diagnosing diastolic dysfunction. Patients with restrictive filling pattern on echocardiography had higher NTBNP levels than those of impaired relaxation pattern (1961.2±304.9 versus 460. 1±92.7pg/mL, p＜0.001). Conclusion The elevation of plasma NT-BNP level in elderly patients with isolated diastolic dysfunction correlates with the severity of their diastolic abnormalities.The level of plasma NT-BNP has an important clinical value in the diagnosis of elderly patients with isolated diastolic dysfunction.
文摘AIM: To clarify the relationship between autophagy and lipotoxicity-induced apoptosis, which is termed "lipoapoptosis," in non-alcoholic steatohepatitis. METHODS: Male C57BL/6J mice were fed a high-fat diet(HFD) for 12 wk, after which the liver histology and expression of proteins such as p62 or LC3 were evaluated. Alpha mouse liver 12(AML12) cells treated with palmitate(PA) were used as an in vitro model. RESULTS: LC3-Ⅱ, p62, and Run domain Beclin-1 interacting and cysteine-rich containing(Rubicon) proteins increased in both the HFD mice and in AML12 cells in response to PA treatment. Rubicon expression was decreased upon c-Jun N-terminal kinase(JNK) inhibition at both the m RNA and the protein level in AML12 cells. Rubicon knockdown in AML12 cells with PA decreased the protein levels of both LC3-Ⅱ and p62. Rubicon expression peaked at 4 h of PA treatment in AML12, and then decreased. Treatment with caspase-9 inhibitor ameliorated the decrease in Rubicon protein expression at 10 h of PA and resulted in enlarged AML12 cells under PA treatment. The enlargement of AML12 cells by PA with caspase-9 inhibition was canceled by Rubicon knockdown.CONCLUSION: The JNK-Rubicon axis enhanced lipoapoptosis, and caspase-9 inhibition and Rubicon had effects that were cytologically similar to hepatocyte ballooning. As ballooned hepatocytes secrete fibrogenic signals and thus might promote fibrosis in the liver, the inhibition of hepatocyte ballooning might provide antifibrosis in the NASH liver.
基金Supported by National Natural Science Foundation of China,No.39870662
文摘To investigate the roles of c-Jun N-terminal kinase (JNK)signaling pathway in vitamin E succinate-induced apoptosisin human gastric cancer SGC-7901 cells.
文摘Our previous results indicated that both the secreted and the intracellular form of full length and 1-97 N-terminal fragment of IGFBP-3 induce apoptosis in PC-3 human prostate cancer cells in an IGF-dependent and independent manner. This study was undertaken to delineate possible down-stream signaling pathways that are involved in this process. Intact IGFBP-3 and its N-terminal 1-97 fragments with or without a signal propeptide were fused to YFP and expressed in PC-3 human prostate cancer cells. In some cases, the putative IGF-binding site was presented in full length IGFBP-3 and its N-terminal fragment was also mutated. Extent of apoptosis was quantified using FACS. Up-regulation of total Stat-1 and activation of phospho-Stat-1 were shown by western blot. TGF-β signal was measured by luciferase reporter assay. Results from inhibitor studies indicated that both the Caspase 8 and caspase 9 pathways are involved in IGFBP-3 (non-secreted form) which induced apoptosis in PC-3 cells. Exogenous addition of IGFBP-3 to PC-3 cells increased Stat-1 protein expression/tyrosine phosphorylation. Interestingly, results also showed that knockdown of Stat-1 by siRNA potentiated the IGFBP-3 induced apoptosis in PC-3 cells. In addition, both full-length IGFBP-3 and its 1-97 Nterminal fragments inhibited TGF-β signaling in these cells. This is the first report that compares the signal transduction pathways involved in apoptotic pathways mediated by IGFBP-3 in PC-3 human prostate cancer cells. Non-secreted form of full length IGFBP-3 and its N-terminal fragments induced apoptosis in PC-3 cells via activation of caspase 8 and caspase 9. Although, only non-secreted form of IGFBP-3 is involved in inducing apoptosis in PC-3 cells via caspase 8 and caspase 9 activation pathways but both secreted and non-secreted forms of IGFBP-3 are involved in modulating Stat-1 and TGF-β pathways to induce apoptotic actions in PC-3 cells. Non-secreted intact IGFBP-3 and its N-terminal fragments induced apoptosis in PC-3 cells via activation of caspase 8 and caspase 9 pathways. Modulation in STAT-1 and TGF-β pathways may also be important for IGFBP-3 induced apoptosis in PC-3 cells in general. These studies clearly demonstrate that secreted and non-secreted FL and 1-97 N-terminal fragments induce apoptosis in PC-3 cells by regulating different mechanistic pathways.
文摘AIM: To illustrate the isoform-specific role and mechanism of c-Jun N-terminal kinases(JNKs) in mouse optic nerve axotomy induced neurotrauma. METHODS: We firstly investigated the expression of JNK1, JNK2, and JNK3 in the retinal ganglion cells(RGCs) by double-immunofluorescent staining. Then we created optic nerve axotomy model in wild type as well as JNK1, JNK2, JNK3, isoform specific gene deficiency mice. With that, we checked the protein expression profile of JNKs and its active form, and quantified the survival RGCs number by immunofluorescence staining. We further explored the molecules underlying isoform specific protective effect by real-time polymerase chain reaction(PCR) and Western blotting assay. RESULTS: We found that all the three isoforms of JNKs were expressed in the RGCs. Deficiency of JNK3, but not JNK1 or JNK2, significantly alleviated optic nerve axotomyinduced RGCs apoptosis. We further established that expression of Noxa, a pro-apoptotic member of BH3 family, was significantly suppressed only in JNK3 gene deficiency mice. But tumor necrosis factor receptor 1(TNFR1) and Fas, two key modulators of death receptor mediated apoptosis pathway, did not display obvious change in the expression. CONCLUSION: It is suggested that mitochondria mediated apoptosis, but not death receptor mediated apoptosis got involved in the JNK3 gene deficiency induced RGCs protection. Our study provides a novel insight into the isoform-specific role of JNKs in neurotrauma and indicates some cues for its therapeutics.
文摘Background: Acute heart failure timely and effective diagnosis and treatment directly affects the prognosis of patients, so early diagnosis of acute heart failure treatment is very important. The current diagnosis of acute heart failure has yet to be further improved. To investigate the relationship between plasma levels of Galectin-3 and NT-proBNP in cardiac structure and function in patients with acute heart failure (AHF) Early detection of failure. Methods: The clinical data of 86 patients with acute heart failure in our hospital were analyzed and followed up. Twenty-six healthy subjects with normal cardiac function were used as control group. The plasma Galectin-3 and NT-proBNP levels were compared between the two groups to observe the value of plasma Galectin-3 combined with NT-proBNP in the diagnosis of acute heart failure. Results: There was no significant difference in the level of Galectin-3 and NT-proBNP between heart function group II and control group, and the levels of cardiac function III and IVG plasma Galectin-3 and NT-proBNP were significantly higher in patients with heart failure Compared with the healthy control group, the patients’ LVEF decreased and their cardiac function increased. The levels of plasma Galectin-3 and NT-proBNP increased significantly (P 0.01). Multivariate Logistic regression analysis demonstrated that plasma levels of Galectin-3 and NT-proBNP were independent of cardiac function. The area under the ROC curve for the combined detection of plasma Galectin-3 and NT-proBNP was greater than the area under the two alone tests. Conclusion: The combined detection of Galectin-3 and NT-proBNP has high sensitivity and specificity in the diagnosis of acute heart failure and can be used as a new detection mode.
文摘Patients with pulmonary embolism (PE) have a high risk of death and it is important to recognize factors associated with high mortality. N-Terminal pro-Brain Natriuretic Peptide (NT-pro BNP) has recently emerged as a promising biomarker for risk assessment in acute pulmonary embolism (PE). The aim of this study is to detect the in hospital prognostic value of NT-pro BNP in patients with acute (PE). Methods: This study included 64 patients diagnosed as (PE) with the mean age of 59.1 ± 16.5 years, 40 patients of them (62.5%) were male. All patients were subjected to 12 leads ECG. X-ray chest, laboratory tests including D-Dimer, troponin I, NT-pro BNP, Doppler ultrasound for the venous system of both lower limbs, Echocardiograhy and 64 multislices CT pulmonary angiography. Results: According to the admission level of NT-pro BNP our patients were divided into two groups: group I included 22 patients with normal NT-pro BNP (less than 300 pg/ml), and group II included 42 patients with elevated NT-pro BNP (more than or equal 300 pg/ml). Patients in group II were found to have a significantly higher incidence of heart failure (28.6% Vs 4.6%, p = 0.025), impaired kidney function (serum creatinine was 1.7 ± 0.6 Vs 1.1 ± 0.2, p = 0.018), tachypnea (85.7% Vs 54.5%, p = 0.006) and cardiogenic shock (26.2% Vs 0%, p = 0.014) but a significantly lower incidence of chest pain (21.4% Vs 45.5%, p = 0.04) and lower left ventricular ejection fraction (51.3% ± 16.9% Vs 67.3% ± 12.8%, p = 0.043) compared to group I. There were a significantly higher treatment with thrombolytic therapy (35.7% Vs 9.1%, p=0.021) and positive inotropics (35.71% Vs 4.55%, p = 0.006) in group II compared to group I. Also group II had a higher need for mechanical ventilation (26.12% Vs 4.55%, p = 0.04) and a longer in hospital stay (19.5 ± 10.3 Vs 5.3 ± 4.5, p = 0.001) than group I. The in hospital mortality was significantly higher in group II compared to group I (19.05% Vs 0.0%, p = 0.042). Conclusion: Elevated NT-pro BNP levels in patients with (PE) are associated with worse short term prognosis in terms of higher morbidity and mortality and it could be used as a valuable prognostic parameter and good indicator for the need of more aggressive therapy.
文摘In order to establish the sequence dependence of RimJ-mediated protein N-terminal acetylation in E. coli, the Z-domain variants differing by the second or third amino acid residue were expressed and analyzed by mass spectrometry. Only subsequent to the initiating methionine residue cleavage, the RimJ-catalyzed N-terminal acetylation mainly occurred at the N-terminal serine and threonine residues and was significantly enhanced by hydrophobic or negatively charged residues in the penultimate position.
文摘Objective:To study the effect of milrinone on the cardiac function and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels in patients with senile refractory heart failure. Methods:90 patients with senile refractory heart failure who were treated in our hospital between August 2013 and August 2016 were collected and divided into control group (n=45) and observation group (n=45) according to the random number table. The control group received regular clinical treatment, and the observation group received regular + milrinone treatment. The cardiac function and serum NT-proBN contents were compared between two groups of patients before and after treatment.Results: Before treatment, the differences in ultrasound and serum cardiac function indexes and serum NT-proBN levels were not statistically significant between two groups of patients. After treatment, ultrasound serum cardiac function parameter LVEDD level in observation group was lower than that in control group while CI and SV levels were higher than those in control group;serum cardiac function indexes Cys-C, GDF-15, sST2 and H-FABP contents were lower than those in control group;serum NT-proBNP content was lower than that in control group.Conclusion: Milrinone therapy can optimize the cardiac function and reduce the serum NT-proBN levels in patients with senile refractory heart failure.
基金supported by Shandong Provincial Natural Science Foundation,China(No.ZR2020QC081,H.Jiang)Youth Innovation Team Talent Introduction Program of Shandong Province(No.20190164,R.Zhang and H.Jiang)。
文摘Numerous strategies for linking desired chemical probes with target peptides and proteins have been developed and applied in the field of biological chemistry.Approaches for site-specific modification of native amino acid residues in test tubes and biological contexts represent novel biological tools for understanding the role of peptides and proteins.Selective N-terminal modification strategies have been broadly studied especially in the last 10 years,as N-terminal positions are typically solvent exposed and provide chemically distinct sites for many peptide and protein targets,making N terminus distinct from other functional groups.A growing number of chemical and enzymatic techniques have been developed to modify N-terminal amino acids,and those techniques have the potential in the fields of medicine,basic research and applied materials science.This review focuses on appraising modification methodologies with the potential for biological applications from the past 10 years.
文摘Background:Clinical assessment and treatment guidance for heart failure depends on a variety of biomarkers.The objective of this study was to investigate the prognostic predictive value of growth differentiation factor-15(GDF-15)and N-terminal prohormone of brain natriuretic peptide(NT-proBNP)in assessing hospitalized patients with acute heart failure(AHF).Methods:In total,260 patients who were admitted for AHF in the First Affiliated Hospital of Nanjing Medical University were enrolled from April 2012 to May 2016.Medical history and blood samples were collected within 24 h after the admission.The primary endpoint was the all-cause mortality within 1 year.The patients were divided into survival group and death group based on the endpoint.With established mortality risk factors and serum GDF-15 level,receiver-operator characteristic(ROC)analyses were performed.Cox regression analyses were used to further analyze the combination values of NT-proBNP and GDF-15.Results:Baseline GDF-15 and NT-proBNP were significantly higher amongst deceased than those in survivors(P<0.001).In ROC analyses,area under curve(AUC)for GDF-15 to predict 1-year mortality was 0.707(95%confidence interval[CI]:0.648–0.762,P<0.001),and for NT-proBNP was 0.682(95%CI:0.622–0.738,P<0.001).No statistically significant difference was found between the two markers(P=0.650).Based on the optimal cut-offs(GDF-15:4526.0 ng/L;NT-proBNP:1978.0 ng/L),the combination of GDF-15 and NT-proBNP increased AUC for 1-year mortality prediction(AUC=0.743,95%CI:0.685–0.795,P<0.001).Conclusions:GDF-15,as a prognostic marker in patients with AHF,is not inferior to NT-proBNP.Combining the two markers could provide an early recognition of high-risk patients and improve the prediction values of AHF long-term prognosis.Clinical trial registration:ChiCTR-ONC-12001944,http://www.chictr.org.cn.
基金This work was supported,in part,by the Sino-European Project on SARS Diagnostics and Antivirals(SEPSDA,contract NO.SP22-CT-2004-003831)by VIZIER(contract no.LSHG-CT-2004-511960)+1 种基金both funded by the European Commission.We acknowledge support from the Sino-German Center for the Promotion of Research,Beijing(grant no.233(202/6))the Schleswig-Holstein Innovation Fund,and the DFG(Hi 611/4 and Cluster of Excellence“Inflammation at Interfaces”).
文摘The main protease(M^(pro))plays a vital role in proteolytic processing of the polyproteins in the replicative cycle of SARS coronavirus(SARS-CoV).Dimerization of this enzyme has been shown to be indispensable for transcleavage activity.However,the auto-processing mechanism of M^(pro),i.e.its own release from the polyproteins through autocleavage,remains unclear.This study elucidates the relationship between the N-terminal autocleavage activity and the dimerization of“immature”M^(pro).Three residues(Arg4,Glu290,and Arg298),which contribute to the active dimer conformation of mature M^(pro),are selected for mutational analyses.Surprisingly,all three mutants still perform N-terminal autocleavage,while the dimerization of mature protease and transcleavage activity following auto-processing are completely inhibited by the E290R and R298E mutations and partially so by the R4E mutation.Furthermore,the mature E290R mutant can resume N-terminal autocleavage activity when mixed with the“immature”C145A/E290R double mutant whereas its trans-cleavage activity remains absent.Therefore,the N-terminal auto-processing of M^(pro) appears to require only two“immature”monomers approaching one another to form an“intermediate”dimer structure and does not strictly depend on the active dimer conformation existing in mature protease.In conclusion,an auto-release model of M^(pro) from the polyproteins is proposed,which will help understand the auto-processing mechanism and the difference between the autocleavage and trans-cleavage proteolytic activities of SARS-CoV M^(pro).
文摘The NifA protein is the central regulator of the nitrogen fixation genes. It activates transcription of nif genes by an alternative holoenzyme form of RNA polymerase containing the σ54 factor. The NifA protein from Klebsiella pneumoniae consists of the N-terminal domain of unknown function, the central catalytic domain with ATPase activity and the C-terminal DNA-binding domain. The Kp NifA protein is sensitive to temperature, while the Enterobacter cloacae NifA protein is less sensitive to temperature than Kp NifA. Our results show that the N-terminal domain of NifA plays the decisive role in the temperature sensitivity of the protein.
文摘STAPHYLOCOCCAL nuclease(SNase A,EC 3.1.4.7),which hydrolyzes the phosphodiesterbond of DNA and RNA,and releases 3’-phosphate mononucleotides and dinucleotides,con-sists of 149 amino acid residues(MW=16 807)without sulfhydryl and disulfide groups.SNase A was originally derived from Staphylococcus aureus.Later the gene of the enzyme wascloned and inserted into several expression systems.Its crystal structure was detected
基金supported by grants from the National Natural Science Foundation of China(91935301,91635301,31601276)the Strategic Priority Research Program“Molecular Mechanism of Plant Growth and Development”of CAS(XDB27010100)+2 种基金the Top Talents Program“One Case One Discussion(Yishiyiyi)”of Shandong Province,ChinaThe Deutsche Forschungsgemeinschaft funded research at Heidelberg University via the Collaborative Research Center 1036(Project-ID:201348542-SFB 1036)individual research grants(WI 3560/4-1,Project-ID:353859218 and WI 3560/7-1,Project-ID:496871662).
文摘N-terminal acetylation is one of the most common protein modifications in eukaryotes,and approximately 40%of human and plant proteomes are acetylated by ribosome-associated N-terminal acetyltransferase A(NatA)in a co-translational manner.However,the in vivo regulatory mechanism of NatA and the global impact of NatA-mediated N-terminal acetylation on protein fate remain unclear.Here,we identify Huntingtin Yeast partner K(HYPK),an evolutionarily conserved chaperone-like protein,as a positive regulator of NatA activity in rice.We found that loss of OsHYPK function leads to developmental defects in rice plant architecture but increased resistance to abiotic stresses,attributable to perturbation of the N-terminal acetylome and accelerated global protein turnover.Furthermore,we demonstrated that OsHYPK is also a substrate of NatA and that N-terminal acetylation of OsHYPK promotes its own degradation,probably through the Ac/N-degron pathway,which could be induced by abiotic stresses.Taken together,our findings suggest that the OsHYPK-NatA complex plays a critical role in coordinating plant development and stress responses by dynamically regulating NatA-mediated N-terminal acetylation and global protein turnover,which are essential for maintaining adaptive phenotypic plasticity in rice.
基金This work was supported in part by grants from the National Pandeng Program and the NationalNatural Science Foundation of China (Grant No. 39930060). We thank Dr. S. B. Xiong for some technical help in cloning the LDHA gene and Prof. K. C. Ruan for the
文摘Lactate dehydrogenase A (LDHA) is a well-characterized tetrameric enzyme. Its N-terminal arm, comprised of an (-helix and a (-strand, was suggested to be essential for subunit interactions. To examine the critical amino acid residues in the N-terminus involved in the subunit association, two single-point mutants, Leu3Pro (L3P) and Ile8Glu (I8E), have been constructed. We compared the stability of WT-LDHA (WT) and its variants by unfolding experiments. For WT, a dimeric but inactive intermediate was observed by size-exclusion chromatography at 0.6-0.8 mol/L GdmCl. Leu3Pro exists in an active tetrameric structure in aqueous solution as WT does, but it dissociates into dimers under lower concentration of GdmCl (0.2 mol/L). In aqueous solution, the Ile8Glu variant exists predominantly in the dimeric form with increased KM and decreased kcat as compared with those of WT and L3P. However, the activity of Ile8Glu increases significantly in the presence of sodium sulfate. In conclusion, two mutants are less stable than WT in oligomer structure. Results also support the fact that some residues in the N-terminal arm, especially the Leu8 in the (-structure, contribute the important binding energies to the dimerization of dimers, which might affect the assembly of the enzyme as well as the catalytic function.
基金supported by grants from Guangdong Science and Technology Department(No.2020B1212060018)National Key Program of the Ministry of Science and Technology Foundation of China(No.2020YFC2004505)+2 种基金Guangdong Provincial Natural Science Foundation(No.2020A1515011467)Guangzhou City Science and Technology Project Plan Foundation(No.202002030149)National Natural Science Foundation of China(No.82002203).
文摘Objective:Early identification of acute kidney injury(AKI)is essential to improve the prognosis of patients with acute heart failure(AHF).We aimed to determine the utility of neutrophil/lymphocyte ratio(NLR),N-terminal prohormone of brain natriuretic peptide(NT-proBNP),urea,and creatinine(Cr),as well as combinations of these,for the prediction of AKI in patients with AHF.Methods:A total of 153 patients with AHF under the care of Sun Yat-sen Memorial Hospital,Sun Yat-sen University from October 2009 to October 2019 were included in this retrospective observational study.Their NLR,NT-proBNP,urea,and Cr concentrations were measured on admission.AKI was defined using the Acute Kidney Injury Network criteria.Receiver operating characteristic(ROC)curves,the areas under the curves(AUCs),sensitivity,and specificity were employed to evaluate the ability of each biomarker and their combinations to identify AKI.This study was approved by the Ethics Committee of Sun Yat-sen Memorial Hospital,Sun Yat-sen University(approval No.SYSEC-KY-KS-2021-126)on June 22,2021.Results:Forty-six(30.1%)participants developed AKI during hospitalization.The NLR and NT-proBNP of the participants with AKI were higher than those without(NLR:median 7.886 vs 4.717,P<0.0001;NT-proBNP,median 6774 vs 2786pg/mL,P<0.0001).ROC analyses demonstrated that high NLR and NT-proBNP were associated with higher incidences of AKI(NLR:cut-off 5.681,AUC 0.716,sensitivity 58.9%,specificity 80.4%;NT-proBNP:cut-off 5320pg/mL,AUC 0.700,sensitivity 72.9%,specificity 65.2%).Moreover,a combination of NLR,NT-proBNP,urea,and Cr yielded an AUC of 0.815,sensitivity 80.4%,and specificity of 74.8%.In addition,the AUCs for the prediction of AKI in the participants with New York Heart Association(NYHA)classes II,III,and IV were 0.936,0.860,and 0.772,respectively,using this combination.Conclusion:A combination of NLR,NT-proBNP,urea,and Cr,measured at admission,may represent a promising tool for the prediction of AKI in patients with AHF.This method performs best for AKI risk assessment in patients with NYHA II,followed by those with NYHA III or IV.
