Study on the Synergistic Effect of Klotho and KRAS on Reducing Ferroptosis After Myocardial Infarction by Regulating RAP1/ERK Signaling Pathway.

Myocardial infarction (MI) is a coronary artery-related disease that seriously threatens human life and is the leading cause of sudden death worldwide, where a lack of nutrients and oxygen leads to an inflammatory response and death of cardiomyocytes. Ferroptosis is a form of non-apoptotic cell death associated with metabolic dysfunction, resulting in abnormal breakdown of glutamine and iron-dependent accumulation of reactive oxygen species (ROS) during metabolism. However, the molecular mechanism of ferroptosis in the pathogenesis of MI and the function of Klotho and KRAS on ferroptosis during MI remain unclear.

Nursing intervention using healing touch in total knee replacement: A randomized controlled study protocol.

Objective:: To assess the efficacy of healing touch (HT) for reducing pain and promoting wound healing in patients undergoing total knee replacement (TKR).

Method:: The experiment will be implemented from December 2020 to December 2021 and was granted through the Research Ethics Committee of Huaihua First People's Hospital (3928/823). 60 patients are included in the study.

Efficacy and safety of bempedoic acid alone or combining with other lipid-lowering therapies in hypercholesterolemic patients: a meta-analysis of randomized controlled trials.

Background: Bempedoic acid is a new drug that reduces cholesterol synthesis via inhibiting ATP citrate lyase. It remains unclear whether the combination of bempedoic acid and other lipid-lowering drugs is better than these drugs alone. This study systematically reviewed the efficacy and safety of bempedoic acid monotherapy or combination togethers in hypercholesterolemic patients.

Klotho gene improves oxidative stress injury after myocardial infarction.

The aim of the present study was to investigate the effects and mechanisms of the Klotho gene in oxidative stress injury after myocardial infarction. Sprague-Dawley rats were divided into five groups (sham, model, pDC316, LY294002, and pDC316-Klotho). Subsequently, the superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) concentrations were measured in myocardial tissues.

Response to Comment on "DNA damage is a pervasive cause of sequencing errors, directly confounding variant identification".

Following the Comment of Stewart , we repeated our analysis on sequencing runs from The Cancer Genome Atlas (TCGA) using their suggested parameters. We found signs of oxidative damage in all sequence contexts and irrespective of the sequencing date, reaffirming that DNA damage affects mutation-calling pipelines in their ability to accurately identify somatic variations.

DNA damage is a pervasive cause of sequencing errors, directly confounding variant identification.

Mutations in somatic cells generate a heterogeneous genomic population and may result in serious medical conditions. Although cancer is typically associated with somatic variations, advances in DNA sequencing indicate that cell-specific variants affect a number of phenotypes and pathologies. Here, we show that mutagenic damage accounts for the majority of the erroneous identification of variants with low to moderate (1 to 5%) frequency.

Differential strand separation at critical temperature: a minimally disruptive enrichment method for low-abundance unknown DNA mutations.

Detection of low-level DNA variations in the presence of wild-type DNA is important in several fields of medicine, including cancer, prenatal diagnosis and infectious diseases. PCR-based methods to enrich mutations during amplification have limited multiplexing capability, are mostly restricted to known mutations and are prone to polymerase or mis-priming errors. Here, we present Differential Strand Separation at Critical Temperature (DISSECT), a method that enriches unknown mutations of targeted DNA sequences purely based on thermal denaturation of DNA heteroduplexes without the need for enzymatic reactions.

Temperature-tolerant COLD-PCR reduces temperature stringency and enables robust mutation enrichment.

Background: Low-level mutations in clinical tumor samples often reside below mutation detection limits, thus leading to false negatives that may impact clinical diagnosis and patient management. COLD-PCR (coamplification at lower denaturation temperature PCR) is a technology that magnifies unknown mutations during PCR, thus enabling downstream mutation detection. However, a practical difficulty in applying COLD-PCR has been the requirement for strict control of the denaturation temperature for a given sequence, to within ±0.

Rapid and sensitive detection of KRAS mutation after fast-COLD-PCR enrichment and high-resolution melting analysis.

KRAS mutations exhibit significant predictive and prognostic value in cancer. Efficient, sensitive, and accurate molecular approaches are required to evaluate KRAS mutation status, even when mutant alleles are restricted to a small portion of a clinical sample, which otherwise contains wild-type alleles. We describe a highly sensitive method to detect KRAS mutations by high-resolution melting (HRM) analysis after mutation enrichment by fast-COLDpolymerase chain reaction (PCR).

COLD-PCR: improving the sensitivity of molecular diagnostics assays.

The detection of low-abundance DNA variants or mutations is of particular interest to medical diagnostics, individualized patient treatment and cancer prognosis; however, detection sensitivity for low-abundance variants is a pronounced limitation of most currently available molecular assays. We have recently developed coamplification at lower denaturation temperature-PCR (COLD-PCR) to resolve this limitation. This novel form of PCR selectively amplifies low-abundance DNA variants from mixtures of wild-type and mutant-containing (or variant-containing) sequences, irrespective of the mutation type or position on the amplicon, by using a critical denaturation temperature.

Multiplex amplification coupled with COLD-PCR and high resolution melting enables identification of low-abundance mutations in cancer samples with low DNA content.

Thorough screening of cancer-specific biomarkers, such as DNA mutations, can require large amounts of genomic material; however, the amount of genomic material obtained from some specimens (such as biopsies, fine-needle aspirations, circulating-DNA or tumor cells, and histological slides) may limit the analyses that can be performed. Furthermore, mutant alleles may be at low-abundance relative to wild-type DNA, reducing detection ability. We present a multiplex-PCR approach tailored to amplify targets of interest from small amounts of precious specimens, for extensive downstream detection of low-abundance alleles.

DNA repair in mammalian mitochondria: Much more than we thought?

For many years, the repair of most damage in mitochondrial DNA (mtDNA) was thought limited to short-patch base excision repair (SP-BER), which replaces a single nucleotide by the sequential action of DNA glycosylases, an apurinic/apyrimidinic (AP) endonuclease, the mitochondrial DNA polymerase gamma, an abasic lyase activity, and mitochondrial DNA ligase. However, the likely array of lesions inflicted on mtDNA by oxygen radicals and the possibility of replication errors and disruptions indicated that such a restricted repair repertoire would be inadequate. Recent studies have considerably expanded our knowledge of mtDNA repair to include long-patch base excision repair (LP-BER), mismatch repair, and homologous recombination and nonhomologous end-joining.

Removal of oxidative DNA damage via FEN1-dependent long-patch base excision repair in human cell mitochondria.

Repair of oxidative DNA damage in mitochondria was thought limited to short-patch base excision repair (SP-BER) replacing a single nucleotide. However, certain oxidative lesions cannot be processed by SP-BER. Here we report that 2-deoxyribonolactone (dL), a major type of oxidized abasic site, inhibits replication by mitochondrial DNA (mtDNA) polymerase gamma and interferes with SP-BER by covalently trapping polymerase gamma during attempted dL excision.

Mechanisms of base selection by the Escherichia coli mispaired uracil glycosylase.

The repair of the multitude of single-base lesions formed daily in cells of all living organisms is accomplished primarily by the base excision repair pathway that initiates repair through a series of lesion-selective glycosylases. In this article, single-turnover kinetics have been measured on a series of oligonucleotide substrates containing both uracil and purine analogs for the Escherichia coli mispaired uracil glycosylase (MUG). The relative rates of glycosylase cleavage have been correlated with the free energy of helix formation and with the size and electronic inductive properties of a series of uracil 5-substituents.

Terminally differentiated muscle cells are defective in base excision DNA repair and hypersensitive to oxygen injury.

The differentiation of skeletal myoblasts is characterized by permanent withdrawal from the cell cycle and fusion into multinucleated myotubes. Muscle cell survival is critically dependent on the ability of cells to respond to oxidative stress. Base excision repair (BER) is the main repair mechanism of oxidative DNA damage.

ATF4-dependent oxidative induction of the DNA repair enzyme Ape1 counteracts arsenite cytotoxicity and suppresses arsenite-mediated mutagenesis.

Arsenite is a human carcinogen causing skin, bladder, and lung tumors, but the cellular mechanisms underlying these effects remain unclear. We investigated expression of the essential base excision DNA repair enzyme apurinic endonuclease 1 (Ape1) in response to sodium arsenite. In mouse 10T(1/2) fibroblasts, Ape1 induction in response to arsenite occurred about equally at the mRNA, protein, and enzyme activity levels.

Impact of cytosine 5-halogens on the interaction of DNA with restriction endonucleases and methyltransferase.

Growing evidence from both prokaryotes and eukaryotes indicates that pyrimidine 5-methyl groups can have profound biological consequences that are mediated by the affinity of DNA-protein interactions. The presence of the 5-methyl group could potentially create a steric block preventing the binding of some proteins whereas the affinity of many other proteins is substantially increased by pyrimidine methylation. In this paper, we have constructed a series of oligonucleotides containing cytosine and a series of 5-substituted cytosine analogues including all halogens.

Genomic instability and aging-like phenotype in the absence of mammalian SIRT6.

The Sir2 histone deacetylase functions as a chromatin silencer to regulate recombination, genomic stability, and aging in budding yeast. Seven mammalian Sir2 homologs have been identified (SIRT1-SIRT7), and it has been speculated that some may have similar functions to Sir2. Here, we demonstrate that SIRT6 is a nuclear, chromatin-associated protein that promotes resistance to DNA damage and suppresses genomic instability in mouse cells, in association with a role in base excision repair (BER).

5-halogenated pyrimidine lesions within a CpG sequence context mimic 5-methylcytosine by enhancing the binding of the methyl-CpG-binding domain of methyl-CpG-binding protein 2 (MeCP2).

Perturbations in cytosine methylation signals are observed in the majority of human tumors; however, it is as yet unknown how methylation patterns become altered. Epigenetic changes can result in the activation of transforming genes as well as in the silencing of tumor suppressor genes. We report that methyl-CpG-binding proteins (MBPs), specific for methyl-CpG dinucleotides, bind with high affinity to halogenated pyrimidine lesions, previously shown to result from peroxidase-mediated inflammatory processes.

Synthesis and characterization of oligonucleotides containing 5-chlorocytosine.

Recent studies have shown that reactive chlorine species, derived from myeloperoxidase-mediated inflammation responses, can modify DNA bases, generating 5-chloropyrimidines. The chlorinated adducts could be mutagenic or perturb DNA-protein interactions; however, the biological significance of these adducts is as yet unknown. We report here a method for the synthesis of 5-chlorocytosine- (ClC-) containing oligonucleotides that will be used in subsequent biochemical and biophysical studies to determine the consequences of pyrimidine chlorination.

DNA ligases ensure fidelity by interrogating minor groove contacts.

DNA ligases, found in both prokaryotes and eukaryotes, covalently link the 3'-hydroxyl and 5'-phosphate ends of duplex DNA segments. This reaction represents a completion step for DNA replication, repair and recombination. It is well established that ligases are sensitive to mispairs present on the 3' side of the ligase junction, but tolerant of mispairs on the 5' side.

[The cell wall-degrading activities of lysin encoded by chlorella virus PBCV-1].

Lysin was isolated from Chlorella NC64A lysate which was infected by Chlorella virus PBCV-1. The enzyme property detection of lysin shows that it contains at least three enzyme activities: chitinase, chitosanase and beta-1, 3-Glucanase. This is consistent with the compose of Chlolrella cell wall.

Repair of the mutagenic DNA oxidation product, 5-formyluracil.

The oxidation of the thymine methyl group can generate 5-formyluracil (FoU). Template FoU residues are known to miscode, generating base substitution mutations. The repair of the FoU lesion is therefore important in minimizing mutations induced by DNA oxidation.

CEACAM1-4S, a cell-cell adhesion molecule, mediates apoptosis and reverts mammary carcinoma cells to a normal morphogenic phenotype in a 3D culture.

In a 3D model of breast morphogenesis, CEACAM1 (carcinoembryonic antigen-related cell adhesion molecule 1) plays an essential role in lumen formation in a subline of the nonmalignant human breast cell line (MCF10A). We show that mammary carcinoma cells (MCF7), which do not express CEACAM1 or form lumena when grown in Matrigel, are restored to a normal morphogenic program when transfected with CEACAM1-4S, the short cytoplasmic isoform of CEACAM1 that predominates in breast epithelia. During the time course of lumen formation, CEACAM1-4S was found initially between the cells, and in mature acini, it was found exclusively in an apical location, identical to its expression pattern in normal breast.

Influence of local duplex stability and N6-methyladenine on uracil recognition by mismatch-specific uracil-DNA glycosylase (Mug).

To maintain genomic integrity, DNA repair enzymes continually remove damaged bases and lesions resulting from endogenous and exogenous processes. These repair enzymes must distinguish damaged bases from normal bases to prevent the inadvertent removal of normal bases, which would promote genomic instability. The mechanisms by which this high level of specificity is accomplished are as yet unresolved.