ABSTRACT
Structure-specific endonucleases (SSEs) play key roles in DNA replication, recombination, and repair. SSEs must be tightly regulated to ensure genome stability but their regulatory mechanisms remain incompletely understood. Here, we show that in the fission yeast Schizosaccharomyces pombe, the activities of two SSEs, Dna2 and Rad16 (ortholog of human XPF), are temporally controlled during the cell cycle by the CRL4Cdt2 ubiquitin ligase. CRL4Cdt2 targets Pxd1, an inhibitor of Dna2 and an activator of Rad16, for degradation in S phase. The ubiquitination and degradation of Pxd1 is dependent on CRL4Cdt2, PCNA, and a PCNA-binding degron motif on Pxd1. CRL4Cdt2-mediated Pxd1 degradation prevents Pxd1 from interfering with the normal S-phase functions of Dna2. Moreover, Pxd1 degradation leads to a reduction of Rad16 nuclease activity in S phase, and restrains Rad16-mediated single-strand annealing, a hazardous pathway of repairing double-strand breaks. These results demonstrate a new role of the CRL4Cdt2 ubiquitin ligase in genome stability maintenance and shed new light on how SSE activities are regulated during the cell cycle.
Subject(s)
DNA-Binding Proteins/genetics , Flap Endonucleases/genetics , Nuclear Proteins/genetics , Schizosaccharomyces pombe Proteins/genetics , DNA Repair/genetics , DNA Replication/genetics , Genomic Instability/genetics , Humans , S Phase/genetics , Schizosaccharomyces/genetics , Ubiquitin/genetics , Ubiquitin-Protein Ligases/genetics , Ubiquitination/geneticsABSTRACT
The BRCT-domain protein Rad4(TopBP1) facilitates activation of the DNA damage checkpoint in Schizosaccharomyces pombe by physically coupling the Rad9-Rad1-Hus1 clamp, the Rad3(ATR) -Rad26(ATRIP) kinase complex, and the Crb2(53BP1) mediator. We have now determined crystal structures of the BRCT repeats of Rad4(TopBP1), revealing a distinctive domain architecture, and characterized their phosphorylation-dependent interactions with Rad9 and Crb2(53BP1). We identify a cluster of phosphorylation sites in the N-terminal region of Crb2(53BP1) that mediate interaction with Rad4(TopBP1) and reveal a hierarchical phosphorylation mechanism in which phosphorylation of Crb2(53BP1) residues Thr215 and Thr235 promotes phosphorylation of the noncanonical Thr187 site by scaffolding cyclin-dependent kinase (CDK) recruitment. Finally, we show that the simultaneous interaction of a single Rad4(TopBP1) molecule with both Thr187 phosphorylation sites in a Crb2(53BP1) dimer is essential for establishing the DNA damage checkpoint.
Subject(s)
Cell Cycle Proteins/metabolism , DNA Damage/genetics , DNA-Binding Proteins , Nuclear Proteins/metabolism , Phosphorylation/genetics , Schizosaccharomyces pombe Proteins/metabolism , Transglutaminases , Binding Sites , Cell Cycle Proteins/chemistry , Cell Cycle Proteins/genetics , Crystallography, X-Ray , DNA-Binding Proteins/chemistry , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Nuclear Proteins/chemistry , Nuclear Proteins/genetics , Protein Binding , Protein Structure, Tertiary , Schizosaccharomyces , Schizosaccharomyces pombe Proteins/chemistry , Schizosaccharomyces pombe Proteins/genetics , Transglutaminases/chemistry , Transglutaminases/genetics , Transglutaminases/metabolismABSTRACT
BACKGROUND: Whether ischemic stroke per se, rather than older age or additional comorbidities, accounts for the adverse prognosis of heart failure (HF) is uncertain. The present study examineed the intrinsic association of ischemic stroke with outcomes in a propensity-matched cohort.MethodsâandâResults:Of 1,351 patients hospitalized with HF, 388 (28.7%) had prior ischemic stroke. Using propensity score for prior ischemic stroke, estimated for each patient, a matched cohort of 379 pairs of HF patients with and without prior ischemic stroke, balanced on 32 baseline characteristics was assembled. At 30 days, prior ischemic stroke was associated with significantly higher risks of the combined endpoint of all-cause death or readmission (hazard ratio [HR]: 1.91; 95% confidence interval [CI]: 1.38 to 2.65; P<0.001), all-cause death (HR: 2.08; 95% CI: 1.28 to 3.38; P=0.003), all-cause readmission (HR: 2.67; 95% CI: 1.78 to 4.01; P<0.001), and HF readmission (HR: 2.11; 95% CI: 1.19 to 3.72; P=0.010). Prior ischemic stroke was associated with a significantly higher risk of all 4 outcomes at both 6 months and 1 year. CONCLUSIONS: Prior ischemic stroke was a potent and persistent risk predictor of death and readmission among patients with HF after accounting for clinical characteristics.
Subject(s)
Heart Failure/complications , Heart Failure/mortality , Ischemic Stroke/complications , Patient Readmission , Propensity Score , Aged , Aged, 80 and over , Cause of Death , Female , Follow-Up Studies , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Prognosis , Prospective Studies , Risk FactorsABSTRACT
The metabolic enzyme cytidine triphosphate synthase has recently been found to form micrometer-sized filamentous structures termed cytoophidia, which are evolutionarily conserved across prokaryotes and eukaryotes. The cytoophidium represents a novel type of membraneless organelle and behaves dynamically inside the cell. The question of how cytoophidia transport is mediated, however, remains unanswered. For the first time, we detected in this study the active transport of cytoophidia, taking advantage of the fission yeast Schizosaccharomyces pombe as an excellent model for studying membraneless organelles. We demonstrated that actin filaments, not microtubules, are responsible for this transport. Furthermore, we determined that Myo52, a type of myosin V, is required for the active transport of cytoophidia. These results reveal the major players critical to the dynamics of cytoophidia and extend our understanding of intracellular transport of membraneless organelles.-Li, H., Ye, F., Ren, J.-Y., Wang, P.-Y., Du, L.-L., Liu, J.-L. Active transport of cytoophidia in Schizosaccharomyces pombe.
Subject(s)
Cytoplasm/metabolism , Schizosaccharomyces/metabolism , Actins/metabolism , Biological Transport, Active , Carbon-Nitrogen Ligases/metabolism , Cytoplasm/enzymology , Optical Imaging , Schizosaccharomyces/enzymology , Schizosaccharomyces pombe Proteins/metabolism , Single-Cell AnalysisABSTRACT
Structure-specific nucleases play crucial roles in many DNA repair pathways. They must be precisely controlled to ensure optimal repair outcomes; however, mechanisms of their regulation are not fully understood. Here, we report a fission yeast protein, Pxd1, that binds to and regulates two structure-specific nucleases: Rad16XPF-Swi10ERCC1 and Dna2-Cdc24. Strikingly, Pxd1 influences the activities of these two nucleases in opposite ways: It activates the 3' endonuclease activity of Rad16-Swi10 but inhibits the RPA-mediated activation of the 5' endonuclease activity of Dna2. Pxd1 is required for Rad16-Swi10 to function in single-strand annealing, mating-type switching, and the removal of Top1-DNA adducts. Meanwhile, Pxd1 attenuates DNA end resection mediated by the Rqh1-Dna2 pathway. Disabling the Dna2-inhibitory activity of Pxd1 results in enhanced use of a break-distal repeat sequence in single-strand annealing and a greater loss of genetic information. We propose that Pxd1 promotes proper DNA repair by differentially regulating two structure-specific nucleases.
Subject(s)
DNA Repair , DNA, Fungal/genetics , Flap Endonucleases/genetics , Gene Expression Regulation, Fungal , Schizosaccharomyces pombe Proteins/genetics , Schizosaccharomyces/genetics , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , DNA Damage , DNA Helicases/genetics , DNA Helicases/metabolism , DNA Topoisomerases, Type I/genetics , DNA Topoisomerases, Type I/metabolism , DNA, Fungal/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Flap Endonucleases/antagonists & inhibitors , Flap Endonucleases/metabolism , Protein Binding , Schizosaccharomyces/enzymology , Schizosaccharomyces pombe Proteins/agonists , Schizosaccharomyces pombe Proteins/antagonists & inhibitors , Schizosaccharomyces pombe Proteins/metabolism , Signal TransductionABSTRACT
OBJECTIVE: To explore the influence of treatment with HMG-CoA reductase inhibitors (statins) on the expression profile of microRNAs (miRNAs) in the plasma of patients with unstable angina (UA). METHODS: The Taqman low-density miRNA array (TLDA) and significance analysis of microarrays (SAM) were used to identify distinct miRNA expression profiles in the plasma of UA patients treated with long-term and regular statins (UA receiving statins, n=6) compared with UA patients who had not received statins therapy before (UA received no statins, n=6). These differentially expressed miRNAs discovered in the profiling were further validated by real-time PCR in another 20 controls with non-cardiac chest pain, 26 UA patients received no statins, and 19 UA patients received statins. RESULTS: By using TLDA and SAM, significantly decreased expression levels of 21 miRNAs were observed in the UA patients receiving statins compared with those who received no statins (fold change>3 and false discovery rate<0.0001%). The unsupervised hierarchical clustering based on miRNA expression clearly separated the UA patients receiving statins from those who received no statins. Consistent with the profiling data, the levels of 5 inflammation-associated miRNAs (miR-106b, miR-21, miR-25, miR-451, and miR-92a) were down regulated (P<0.05) in the UA patients receiving statins compared with those who received no statins. CONCLUSION: A group of inflammation-associated miRNAs, consisting of miR-106b, miR-21, miR-25, miR-451, and miR-92a, could be decreased by treatment with statins and may be used as a novel biomarker for effectiveness of statins therapy in patients with UA.
Subject(s)
Angina, Unstable/drug therapy , Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Inflammation/metabolism , MicroRNAs/metabolism , Angina, Unstable/metabolism , Angina, Unstable/physiopathology , Biomarkers/metabolism , Chest Pain , Cluster Analysis , Humans , Inflammation/physiopathology , Microarray Analysis , Real-Time Polymerase Chain ReactionABSTRACT
Background: The tertiary lymphatic structure (TLS) is an important component of the tumor immune microenvironment and has important significance in patient prognosis and response to immune therapy. However, the underlying mechanism of TLS in soft tissue sarcoma remains unclear. Methods: A total of 256 RNAseq and 7 single-cell sequencing samples were collected from TCGA-SARC and GSE212527 cohorts. Based on published TLS-related gene sets, four TLS scores were established by GSVA algorithm. The immune cell infiltration was calculated via TIMER2.0 and "MCPcounter" algorithms. In addition, the univariate, LASSO, and multivariate-Cox analyses were used to select TLS-related and prognosis-significant hub genes. Single-cell sequencing dataset, clinical immunohistochemical, and cell experiments were utilized to validate the hub genes. Results: In this study, four TLS-related scores were identified, and the total-gene TLS score more accurately reflected the infiltration level of TLS in STS. We further established two hub genes (DUSP9 and TNFSF14) prognosis markers and risk scores associated with soft tissue sarcoma prognosis and immune therapy response. Flow cytometry analysis showed that the amount of CD3, CD8, CD19, and CD11c positive immune cell infiltration in the tumor tissue dedifferentiated liposarcoma patients was significantly higher than that of liposarcoma patients. Cytological experiments showed that soft tissue sarcoma cell lines overexpressing TNFSF14 could inhibit the proliferation and migration of sarcoma cells. Conclusion: This study systematically explored the TLS and related genes from the perspectives of bioinformatics, clinical features and cytology experiments. The total-gene TLS score, risk score and TNFSF14 hub gene may be useful biomarkers for predicting the prognosis and immunotherapy efficacy of soft tissue sarcoma.
Subject(s)
Biomarkers, Tumor , Immunotherapy , Sarcoma , Tumor Microenvironment , Humans , Sarcoma/genetics , Sarcoma/therapy , Sarcoma/immunology , Sarcoma/diagnosis , Biomarkers, Tumor/genetics , Prognosis , Immunotherapy/methods , Tumor Microenvironment/immunology , Tumor Microenvironment/genetics , Gene Expression Regulation, Neoplastic , Female , Male , Tumor Necrosis Factor Ligand Superfamily Member 14/genetics , Gene Expression Profiling , Single-Cell AnalysisABSTRACT
OBJECTIVE: The aim of this study was to assess the safety of fenofibrate-statin combination therapy. METHODS: Medline, Cochrane Library, Web of Knowledge and CNKI were searched for 2184 randomized controlled trials. Finally, twenty-six studies with a total of 9494 participants were included in this analysis. RESULTS: Compared with statins group, the fenofibrate-statin group had significantly higher incidence of aminotransferase elevations (OR 1.67, 95%CI 1.22-2.30, P < 0.05) . The two groups had identical incidence of creatin kinase elevations (OR 0.86, 95%CI 0.62-1.20, P > 0.05) , muscle-associated adverse events (OR 0.98, 95%CI 0.88-1.09, P > 0.05) and withdrawals due to hepatotoxicity or muscle toxicity. The safety of fenofibrate + standard-dose statin regimens were similar to those in fenofibrate-statin group. CONCLUSION: Combined fenofibrate-statin treatment is generally safe and well tolerated, liver function should be monitored before and during and after therapy.
Subject(s)
Fenofibrate/therapeutic use , Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Hypolipidemic Agents/therapeutic use , Adult , Aged , Aged, 80 and over , Combined Modality Therapy , Humans , Male , Middle Aged , Randomized Controlled Trials as TopicABSTRACT
MicroRNAs (miRNAs) are a class of ~22nt long non-coding RNAs. They are evolutionarily conserved and play essential roles in the regulation of post-transcriptional gene expression. The rapidly developing next generation sequencing (NGS) has important applications in miRNA detection. This review is focused on the mechanism of three NGS platforms and their applications in miRNA detection. In contrast to traditional methods, NGS has major advantages: high throughput, precise, accurate, and repeatable. Its application includes new miRNAs exploration, detection of miRNA*, miRNA editing, and isomiR and target mRNA detection. As NGS develops, the cost of sequencing is declining which makes it possible for NGS to be widely used in the coming years. Next generation sequencing will greatly promote researches of miRNAs.
Subject(s)
MicroRNAs/chemistry , MicroRNAs/genetics , Sequence Analysis, RNA/methods , RNA Editing/genetics , RNA, Messenger/geneticsABSTRACT
Time-restricted eating (TRE) is known to improve metabolic health, whereas very few studies have compared the effects of early and late TRE (eTRE and lTRE) on metabolic health. Overweight and obese young adults were randomized to 6-h eTRE (eating from 7 a.m. to 1 p.m.) (n = 21), 6-h lTRE (eating from 12 p.m. to 6 p.m.) (n = 20), or a control group (ad libitum intake in a day) (n = 19). After 8 weeks, 6-h eTRE and lTRE produced comparable body weight loss compared with controls. Compared with control, 6-h eTRE reduced systolic blood pressure, mean glucose, fasting insulin, insulin resistance, leptin, and thyroid axis activity, whereas lTRE only reduced leptin. These findings shed light on the promise of 6-h eTRE and lTRE for weight loss. Larger studies are needed to assess the promise of eTRE to yield better thyroid axis modulation and overall cardiometabolic health improvement.
ABSTRACT
Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), which is produced primarily by macrophages and is predominately found in the blood and in atherosclerotic plaques, represents a potentially promising target for combating atherosclerosis. Although statins are known to decrease the levels and activity of circulating and plaque Lp-PLA(2) during atherosclerosis, little is known regarding the mechanisms underlying inhibition of Lp-PLA(2) by statins. Therefore, the aim of this study was to explore the molecular mechanisms responsible for inhibition of Lp-PLA(2) by statins. Our results showed that treatment with simvastatin inhibited lipopolysaccharide (LPS)-induced increases in Lp-PLA(2) expression and secreted activity in human monocytederived macrophages in a dose- and time-dependent manner. These effects could be reversed by treatment with mevalonate or geranylgeranyl pyrophosphate (GGPP), but not by treatment with squalene or farnesyl pyrophosphate. Treatment with the Rho inhibitor C3 exoenzyme also inhibited LPS-induced increases in Lp-PLA(2) expression and secreted activity, mimicking the effects of simvastatin. In addition, treatment with simvastatin blocked LPS-induced activation of RhoA, which could be abolished by treatment with GGPP. Inhibition of p38 mitogen-activated protein kinase (MAPK), but not extracellular signal regulated kinase 1/2 or Jun N-terminal kinase, suppressed LPS-induced increases in Lp-PLA(2) expression and secreted activity, similar to the effects of simvastatin. Treatment of human monocytederived macrophages with either simvastatin or C3 exoenzyme prevented LPS-induced activation of p38 MAPK, which could be abolished by treatment with GGPP. Together, these results suggest that simvastatin reduces Lp-PLA(2) expression and secreted activity in LPS-stimulated human monocytederived macrophages through the inhibition of the mevalonateGGPPRhoA-p38 MAPK pathway. These observations provide novel evidence that statins have pleiotropic effects and suggest that inhibition of Lp-PLA(2) via this mechanism may account, at least in part, for the clinical benefit of statins in combating atherosclerosis.
Subject(s)
1-Alkyl-2-acetylglycerophosphocholine Esterase/antagonists & inhibitors , Macrophages/drug effects , Mevalonic Acid/antagonists & inhibitors , Polyisoprenyl Phosphates/antagonists & inhibitors , Simvastatin/pharmacology , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , rhoA GTP-Binding Protein/antagonists & inhibitors , 1-Alkyl-2-acetylglycerophosphocholine Esterase/metabolism , Cells, Cultured , Humans , Lipopolysaccharides/toxicity , MAP Kinase Signaling System/drug effects , MAP Kinase Signaling System/physiology , Macrophages/enzymology , Mevalonic Acid/metabolism , Polyisoprenyl Phosphates/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism , rhoA GTP-Binding Protein/metabolismABSTRACT
OBJECTIVE: To detect the impaired glucose metabolism in dyslipidemic patients and explore whether the type of dyslipidemia affects the type of impaired glucose metabolism. METHODS: In our study, 197 patients without diabetes or cardiovascular disease history were divided into 4 groups according to fasting serum lipid levels: hypercholesterolemic group (HCh group, 45 patients); hypertriglyceridemic group (HTG group, 46 patients); combined dyslipidemic group (58 patients) and control group (48 patients). Serum insulin and glucose levels were detected in fasting situation. HOMA-IR was calculated. And then the patients received 75 g oral glucose tolerance test (OGTT) and their GLU120 levels were detected. RESULTS: The GLU120 levels in HTG group [(10.5±3.2) mmol/L] and combined dyslipidemic group [(12.0±5.4) mmol/L] were significantly higher than those in control group [(8.7±3.5) mmol/L, P=0.045 and 0.024, respectively]. HTG group (39.1%) and combined dyslipidemic group (31.0%) also had higher impaired glucose tolerance (IGT) incidence ratios than those in control group (22.9%, P=0.009 and 0.014, respectively). In subgroup study of patients with fasting glucose levels below 6.1 mmol/L, the incidence ratios of IGT in HTG group and combined dyslipidemic group were 51.4% and 43.9%, respectively, which were significantly higher than those in control group (29.7%, P=0.009 and 0.015, respectively). CONCLUSION: There exists a definite ratio of undiscovered impaired glucose metabolism in dyslipidemic patients who have not suffered from cardiovascular disease, especially in hypertriglyceridemic and combined dyslipidemic group. OGTT is suggested to be brought into effect in order that impaired glucose metabolism would be detected in earlier stage.
Subject(s)
Dyslipidemias/classification , Glucose Intolerance/complications , Glucose Metabolism Disorders/complications , Hyperlipidemias/complications , Aged , Dyslipidemias/blood , Female , Glucose Intolerance/blood , Glucose Metabolism Disorders/blood , Glucose Tolerance Test , Humans , Hyperlipidemias/blood , Hypertriglyceridemia/blood , Hypertriglyceridemia/complications , Male , Middle AgedABSTRACT
Long noncoding RNAs (lncRNAs) are emerging as critical regulators of gene expression and play fundamental roles in immune regulation. Growing evidence suggests that immune-related genes and lncRNAs can serve as markers to predict the prognosis of patients with cancers, including hepatocellular carcinoma (HCC). This study aimed to contract an immune-related lncRNA (IR-lncRNA) signature for prospective assessment to predict early recurrence of HCC. A total of 319 HCC samples under radical resection were randomly divided into a training cohort (161 samples) and a testing cohort (158 samples). In the training dataset, univariate, lasso, and multivariate Cox regression analyses identified a 9-IR-lncRNA signature closely related to disease-free survival. Kaplan-Meier analysis, principal component analysis, gene set enrichment analysis, and nomogram were used to evaluate the risk model. The results were further confirmed in the testing cohort. Furthermore, we constructed a competitive endogenous RNA regulatory network. The results of the present study indicated that this 9-IR-lncRNA signature has important clinical implications for improving predictive outcomes and guiding individualized treatment in HCC patients. These IR-lncRNAs and regulated genes may be potential biomarkers associated with the prognosis of HCC.
ABSTRACT
Objective: This study aimed to elucidate the pharmacological effects of sesamin (Ses) and its mechanism of action towards PM2.5-induced cardiovascular injuries. Method: Forty Sprague Dawley (SD) rats were randomly divided into five groups: a saline control group; a PM2.5 exposure group; and low-, middle-, and high-dose Ses pretreatment groups. The SD rats were pretreated with different concentrations of Ses for 21 days. Afterward, the rats were exposed to ambient PM2.5 by intratracheal instillation every other day for a total of three times. The levels of inflammatory markers, including tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1ß), and interleukin-6 (IL-6), and indicators related to oxidative responses, such as total superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA), were measured in the blood and heart. The expression of ferroptosis-related proteins in heart tissues was determined via western blot and immunohistochemistry. Results: Ses pretreatment substantially ameliorated cardiovascular injuries in rats as evidenced by the decrease in the pathological score and collagen area. The decreased levels of SOD, GSH, and GSH-Px in the heart and serum were inhibited by Ses. In addition, Ses not only notably increased the activity of antioxidant enzymes but also reduced the levels of MDA, CK, LDH, CK-MB, IL-6, TNF-α, IL-1ß, and IL-6. Furthermore, Ses pretreatment upregulated the expression levels of GPX4, SLC7A11, TFRC, and FPN1 and inhibited the expression levels of FTH1 and FTL. Conclusion: Ses pretreatment could ameliorate PM2.5-induced cardiovascular injuries perhaps by inhibiting ferroptosis. Therefore, Ses pretreatment may be a novel strategy for the prevention and treatment of PM2.5-induced cardiovascular injury.
Subject(s)
Antioxidants/pharmacology , Cardiovascular Diseases/prevention & control , Dioxoles/pharmacology , Ferroptosis/drug effects , Lignans/pharmacology , Particulate Matter/adverse effects , Animals , Disease Models, Animal , Rats , Rats, Sprague-DawleyABSTRACT
Hypocholesterolemia is characterized by serum total cholesterol that is lower than the 5th percentile for age and sex, or the cut-off value which predicts the adverse prognosis by epidemiological study. Unlike hypercholesterolemia, physicians pay less attention to the morbidity, causes and consequences of hypocholesterolemia in clinical practice. In fact, hypocholesterolemia is a common dislipidemia, and mainly results from secondary factors. The causes of primary hypocholesterolemia are some disorders owing to genetic mutation in the pathway of cholesterol absorption, biosynthesis or metabolism, including abetalipoproteinemia, hypobetalipoproteinemia, Tangier disease, chylomicron retention disease and inherited disorders of cholesterol biosynthesis. The causes of secondary hypocholesterolemia comprise anemia, hyperthyroidism, malignancy, live disease, critical illness, serious stress, malabsorption or malnutrition, acute or chronic infection, chronic inflammation, and use of some drugs. In addition, what's more important is that hypocholesterolemia can result in some adverse events, such as increased mortality, intracerebral hemorrhage, cancer, infection, adrenal failure, suicide and mental disorder. Therefore, with the practice of intensive lipid-lowering treatment and the tendency to the increased indications of statins, it's high time that physicians attached more importance to hypocholesterolemia.
Subject(s)
Dyslipidemias/physiopathology , Hypolipoproteinemias/etiology , Hypolipoproteinemias/physiopathology , Animals , Dyslipidemias/etiology , HumansABSTRACT
OBJECTIVE: To investigate the effects of simvastatin on lipopolysaccharides (LPS) induced upregulation of Lp-PLA(2) in human peripheral blood monocytes-macrophages and the related mechanisms. METHODS: Peripheral blood monocytes of healthy volunteer were isolated and incubated for 2-3 days. Monocytes were incubated with various concentrations of LPS for 6 h or with 1 µg/ml of LPS for different times in LPS group. In simvastatin group and MAPK inhibitors groups, cells were pre-treated with simvastatin (10(-2) - 10(-7) mmol/L) or various MAPK inhibitors (10 µmol/L SB203580, 20 µmol/L U0126, and 20 µmol/L SP600125) before LPS co-incubation. Lp-PLA(2) activity was measured by chronometry, Lp-PLA(2) mRNA expression was detected by RT-PCR. Protein expressions of Lp-PLA(2) and p38MAPK and phosphorylated p38MAPK were examined by Western blot. RESULTS: (1) LPS significantly upregulated Lp-PLA(2) mRNA and protein expression, as well as the enzyme activity in a time and concentration dependent manner, which could be significantly attenuated by simvastatin in a time and concentration dependent manner. (2) Simvastatin significantly reduced LPS-induced p38MAPK phosphorylation. The p38 MAPK inhibitor SB203580, but not MEK1/2 inhibitor U0126 and JNK inhibitor SP600125, completely prevented LPS-mediated up-regulation of Lp-PLA(2) at protein level. CONCLUSION: This study demonstrated that LPS significantly upregulated Lp-PLA(2) mRNA and protein expression, as well as the enzyme activity in a time and concentration dependent manner via Rho-p38MAPK pathway, which could be significantly suppressed by simvastatin.
Subject(s)
Macrophages/drug effects , Macrophages/metabolism , Phospholipases A2/metabolism , Simvastatin/pharmacology , 1-Alkyl-2-acetylglycerophosphocholine Esterase , Anthracenes/pharmacology , Butadienes/pharmacology , Cells, Cultured , Humans , Imidazoles/pharmacology , Lipopolysaccharides/pharmacology , Monocytes/drug effects , Monocytes/metabolism , Nitriles/pharmacology , Phosphorylation , Pyridines/pharmacology , RNA, Messenger/genetics , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
OBJECTIVE: To evaluate the efficacy and safety of micronised fenofibrate on lipid and uric acid metabolism in patients with hyperlipidemia. METHODS: A total of 116 patients with hypertriglyceridemia and hyperuricemia received 200 mg micronised fenofibrate for 4 weeks. Physical and laboratory investigations of lipid profiles, serum uric acid, and 24 h urine uric acid, for adverse effects were assessed. RESULTS: (1) Serum triglyceride (TG) was significantly reduced by 51%, whilst high density lipoprotein cholesterol (HDL-C) increased 24% after 4-week fenofibrate treatment. Moreover, serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) were reduced by 10% and 12%, respectively. (2) Serum uric acid levels were significantly reduced by 28.3% [from (462.8+/-73.5) micromol/L to (320.1+/-83.0) micromol/L] after fenofibrate treatment, independent of baseline uric acid levels. There was no difference in serum uric acid changes between male gender and female gender(29.8% and 25.1%, respectively). (3) Urine uric acid levels were increased by 36.0% [from (2 874.2+/-503.4) micromol/L to (3 604.2+/-769.7) micromol/L]. The urine uric acid changes were 41.1% in male gender group and 33.4% in female gender group. The uric acid clearance/creatinin clearance ratio was increased in all cases after treatment. CONCLUSION: Micronised fenofibrate treatment could significantly improve lipid and uric acid metabolism in patients with hypertriglyceridemia and hyperuricemia, and is generally safe and well tolerated. The anti-hyperuricemic effect of fenofibrate is a result of increasing the urinary excertion of uric acid, independent of baseline level and gender.
Subject(s)
Fenofibrate/therapeutic use , Hyperlipidemias/drug therapy , Hyperuricemia/drug therapy , Triglycerides/blood , Uric Acid/blood , Adult , Aged , Female , Humans , Hyperlipidemias/complications , Hyperuricemia/complications , Hypolipidemic Agents/therapeutic use , Lipids/blood , Male , Middle AgedABSTRACT
Gene essentiality is a variable phenotypic trait, but to what extent and how essential genes can become dispensable for viability remain unclear. Here, we investigate 'bypass of essentiality (BOE)' - an underexplored type of digenic genetic interaction that renders essential genes dispensable. Through analyzing essential genes on one of the six chromosome arms of the fission yeast Schizosaccharomyces pombe, we find that, remarkably, as many as 27% of them can be converted to non-essential genes by BOE interactions. Using this dataset we identify three principles of essentiality bypass: bypassable essential genes tend to have lower importance, tend to exhibit differential essentiality between species, and tend to act with other bypassable genes. In addition, we delineate mechanisms underlying bypassable essentiality, including the previously unappreciated mechanism of dormant redundancy between paralogs. The new insights gained on bypassable essentiality deepen our understanding of genotype-phenotype relationships and will facilitate drug development related to essential genes.
Subject(s)
Epistasis, Genetic , Genes, Essential , Genes, Fungal/genetics , Schizosaccharomyces/genetics , Chromosome Mapping , Chromosomes , Databases, Genetic , Evolution, Molecular , Gene Regulatory Networks , Genotype , Models, Genetic , Phenotype , Plasmids/genetics , Species SpecificityABSTRACT
BACKGROUND: Despite the growing epidemic of heart failure (HF), there is limited data available to systematically compare non-cardiac comorbidities in the young-old, old-old, and oldest-old patients hospitalized for HF. The precise differences will add valuable information for better management of HF in elderly patients. METHODS: A total of 1053 patients aged 65 years or older hospitalized with HF were included in this study. Patients were compared among three age groups: (1) young-old: 65 to 74 years, (2) old-old: 75 to 84 years, and (3) oldest-old: ≥85 years. Clinical details of presentation, comorbidities, and prescribed medications were recorded. RESULTS: The mean age was 76.7 years and 12.7% were 85 years or older. Most elderly patients with HF (97.5%) had at least one of the non-cardiac comorbidities. The patterns of common non-cardiac comorbidities were different between the young-old and oldest-old group. The three most common non-cardiac comorbidities were anemia (53.6%), hyperlipidemia (45.9%), and diabetes (42.4%) in the young-old group, while anemia (73.1%), infection (58.2%), and chronic kidney disease (44.0%) in the oldest-old group. Polypharmacy was observed in 93.0% elderly patients with HF. Additionally, 29.2% patients were diagnosed with infection, and 67.0% patients were prescribed antibiotics. However, 60.4% patients were diagnosed with anemia with only 8.9% of them receiving iron repletion. CONCLUSIONS: Non-cardiac comorbidities are nearly universal in three groups but obviously differ by age, and inappropriate medications are very common in elderly patients with HF. Further treatment strategies should be focused on providing optimal medications for age-specific non-cardiac conditions.
Subject(s)
Heart Failure/complications , Age Factors , Aged , Aged, 80 and over , Anemia/epidemiology , Comorbidity , Female , Heart Failure/drug therapy , Hospitalization , Humans , Male , PolypharmacyABSTRACT
OBJECTIVE: To determine whether acute withdrawal of simvastatin treatment in healthy normocholesterolemic men impairs the brachial artery endothelial function. METHODS: The study was performed on 16 healthy, young male subjects with desirable serum levels of cholesterol. They were administered with simvastatin (20 mg/d) for 4 weeks. Endothelial dependent flow-mediated vasodilation (FMD) was assessed on the brachial artery using high-resolution ultrasound, and fasting serum lipid profiles as well as vasoactive substances [NO, endothelin (ET) and 6-keto-PGF1 alpha] were measured. The parameters mentioned above were obtained at indicated time points before and after simvastatin treatment. RESULTS: Simvastatin treatment for 4 weeks significantly improved FMD and reduced low density LDL-C and total TC levels. Withdrawal of simvastatin, however, resulted in dramatic impairment of endothelium-dependent relaxation on the first day after withdrawal [(4.6 +/- 0.48)% and (10.9 +/- 0.89)%, P < 0.01], Furthermore, FMD decreased significantly as compared with baseline level [(4.6 +/- 0.48 )% vs (6.44 +/- 0.47)%, P < 0.01]. Serum NO level varied according to the change of endothelial-dependent relaxation (gamma = 0.496, P < 0.01). After discontinuing simvastatin therapy, plasma ET increased and plasma 6-keto-PGF1 alpha decreased progressively. In addition, serum TC and LDL-C were not significantly modified during the initial 2 days. No correlation was shown between FMD and serum LDL-C level (gamma = -0.172, P = 0.101). CONCLUSIONS: Withdrawal of simvastatin not only abrogates the beneficial effect on endothelial function of healthy normocholesterolemic men rapidly, but also induces further endothelial deterioration as compared with pretreatment status. This adverse effect is independent of serum cholesterol. The underlying mechanism may be related to the suppression of endothelial NO production.