Concomitant expression patterns of CDX2 and SATB2 as prognostic factors in stage III colorectal cancers.

CDX2 and SATB2 are often used as biomarkers for identification of colorectal origin in primary or metastatic adenocarcinomas. Loss of CDX2 or SATB2 expression has been associated with poor prognosis in patients with colorectal cancer (CRC). However, little is known regarding clinicopathological features, including prognosis, of CRCs with concomitant loss of CDX2 and SATB2. A total of 431 stage III CRCs were analyzed for their expression status in CDX2 and SATB2 using tissue microarray-based immunohistochemistry and expression status was correlated with clinicopathological variables, molecular alterations, and survival. CDX2-negative (CDX2-) CRCs and SATB2-negative (SATB2-) CRCs were found in 8.1 % and 17.2 % of CRCs, respectively, whereas both CDX2-negative and SATB2-negative (CDX2-/SATB2-) CRCs comprised 3.2 % of the CRCs. On survival analysis, neither CDX2-/SATB2+ nor CDX2+/SABT2- CRCs but CDX2-/SATB2- CRCs were associated with poor prognosis. CDX2-/SATB2- CRCs showed significant associations with tumor subsite of right colon, poor differentiation, decreased expression of CK20, aberrant expression of CK7, CIMP-high, MSI-high, and BRAF mutation. In summary, our results suggest that concomitant loss of CDX2 and SATB2 is a prognostic biomarker but isolated loss of CDX2 or SATB2 is not a prognostic biomarker for stage III CRCs.

Mechanism of ubiquitin-chain formation by the human anaphase-promoting complex.

The anaphase-promoting complex (APC/C) orchestrates progression through mitosis by decorating cell-cycle regulators with ubiquitin chains. To nucleate chains, the APC/C links ubiquitin to a lysine in substrates, but to elongate chains it modifies lysine residues in attached ubiquitin moieties. The mechanism enabling the APC/C, and ubiquitin ligases in general, to switch from lysine residues in substrates to specific ones in ubiquitin remains poorly understood. Here, we determine the topology and the mechanism of assembly for the ubiquitin chains mediating functions of the human APC/C. We find that the APC/C triggers substrate degradation by assembling K11-linked ubiquitin chains, the efficient formation of which depends on a surface of ubiquitin, the TEK-box. Strikingly, homologous TEK-boxes are found in APC/C substrates, where they facilitate chain nucleation. We propose that recognition of similar motifs in substrates and ubiquitin enables the APC/C to assemble ubiquitin chains with the specificity and efficiency required for tight cell-cycle control.

Construction and validation of a cuproptosis-related diagnostic gene signature for atrial fibrillation based on ensemble learning.

BACKGROUND: Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. Nonetheless, the accurate diagnosis of this condition continues to pose a challenge when relying on conventional diagnostic techniques. Cell death is a key factor in the pathogenesis of AF. Existing investigations suggest that cuproptosis may also contribute to AF. This investigation aimed to identify a novel diagnostic gene signature associated with cuproptosis for AF using ensemble learning methods and discover the connection between AF and cuproptosis. RESULTS: Two genes connected to cuproptosis, including solute carrier family 31 member 1 (SLC31A1) and lipoic acid synthetase (LIAS), were selected by integration of random forests and eXtreme Gradient Boosting algorithms. Subsequently, a diagnostic model was constructed that includes the two genes for AF using the Light Gradient Boosting Machine (LightGBM) algorithm with good performance (the area under the curve value > 0.75). The microRNA-transcription factor-messenger RNA network revealed that homeobox A9 (HOXA9) and Tet methylcytosine dioxygenase 1 (TET1) could target SLC31A1 and LIAS in AF. Functional enrichment analysis indicated that cuproptosis might be connected to immunocyte activities. Immunocyte infiltration analysis using the CIBERSORT algorithm suggested a greater level of neutrophils in the AF group. According to the outcomes of Spearman's rank correlation analysis, there was a negative relation between SLC31A1 and resting dendritic cells and eosinophils. The study found a positive relationship between LIAS and eosinophils along with resting memory CD4+ T cells. Conversely, a negative correlation was detected between LIAS and CD8+ T cells and regulatory T cells. CONCLUSIONS: This study successfully constructed a cuproptosis-related diagnostic model for AF based on the LightGBM algorithm and validated its diagnostic efficacy. Cuproptosis may be regulated by HOXA9 and TET1 in AF. Cuproptosis might interact with infiltrating immunocytes in AF.

[Metabolic mechanism and intervention strategy of atrial fibrillation in the elderly].

Atrial fibrillation (AF) is a cardiovascular epidemic that occurs primarily in the elderly with primary cardiovascular diseases, leading to severe consequences such as stroke and heart failure. The heart is an energy-consuming organ, which requires a high degree of metabolic flexibility to ensure a quick switch of metabolic substrates to meet its energy needs in response to physiological and pathological stimulation. Metabolism is closely related to the occurrence of AF, and AF patients manifest metabolic inflexibility, such as insulin resistance and the metabolic shift from aerobic metabolism to anaerobic glycolysis. Moreover, our research group and the others have shown that metabolic inflexibility is a crucial pathologic mechanism for AF. Energy metabolism is closely linked to the aging process and aging-related diseases, and impaired metabolic flexibility is considered as an essential driver of aging. Therefore, this review focuses on the alteration of metabolic flexibility in the elderly and reveals that impaired metabolic flexibility may be an important driver for the high prevalence of AF in the elderly, hoping to provide intervention strategies for the prevention and treatment of AF in the elderly.

Hyper-O-GlcNAcylation impairs insulin response against reperfusion-induced myocardial injury and arrhythmias in obesity.

Myocardial ischemia/reperfusion (I/R) injury is a major determinant of morbidity and mortality in patients undergoing treatment for cardiac disease. A variety of treatments are reported to have benefits against reperfusion injury, yet their cardioprotective effects seem to be diminished in obesity, and the underlying mechanism remains elusive. In this study, we found that db/db mice exhibit cardiac hyper-O-GlcNAcylation. In parallel, palmitate treatment (200 mM; 12 h) in H9c2 cells showed an increase in global protein O-GlcNAcylation, along with an impaired insulin response against reperfusion injury. To investigate whether O-GlcNAcylation underlies this phenomenon, glucosamine was used to increase global protein O-GlcNAc levels. Interestingly, histological staining, electrophysiological studies, serum cardiac markers and oxidative stress biomarker assays showed that preischemic treatment with glucosamine attenuated insulin cardioprotection against myocardial infarction, arrhythmia and oxidative stress. Mechanistically, glucosamine treatment decreased insulin-stimulated Akt phosphorylation, a key modulator of cell survival. Furthermore, inhibition of O-GlcNAcylation via 6-diazo-5-oxo-l-norleucine (DON) apparently increased insulin-induced Akt phosphorylation and restored its cardioprotective response against reperfusion injury in palmitate-induced insulin-resistant H9c2 cells. Our findings demonstrated that obesity-induced hyper-O-GlcNAcylation might contribute to the attenuation of insulin cardioprotection against I/R injury.

Ubiquitin-dependent regulation of COPII coat size and function.

Packaging of proteins from the endoplasmic reticulum into COPII vesicles is essential for secretion. In cells, most COPII vesicles are approximately 60-80 nm in diameter, yet some must increase their size to accommodate 300-400 nm procollagen fibres or chylomicrons. Impaired COPII function results in collagen deposition defects, cranio-lenticulo-sutural dysplasia, or chylomicron retention disease, but mechanisms to enlarge COPII coats have remained elusive. Here, we identified the ubiquitin ligase CUL3-KLHL12 as a regulator of COPII coat formation. CUL3-KLHL12 catalyses the monoubiquitylation of the COPII-component SEC31 and drives the assembly of large COPII coats. As a result, ubiquitylation by CUL3-KLHL12 is essential for collagen export, yet less important for the transport of small cargo. We conclude that monoubiquitylation controls the size and function of a vesicle coat.

A novel device for air removal from vascular access line: a bench study.

Efficient air removal from a vascular access line is a key step to prevent air embolism. Existing devices, especially for rapid infusers, are far from optimum. In this study, we developed a novel device, vascular access line air removal device (VALARD), and compared its efficiency of air removal and pause time of forward bulk flow with a commonly used device, the Belmont pump. Part I experiment, saline was infused at a forward bulk flow rate of 250, 500, and 750 mL/min. Meanwhile, air was introduced into the infusion line at a rate of 5, 10, and 15 mL/min for each bulk flow rate. Air bubbles > 10 µL downstream from either the VALARD or the Belmont pump and the fraction of pause time of the forward bulk flow were determined. Part II experiment, 120 mL of air was rapidly introduced into the VALARD at a bulk flow rate of about 500 mL/min. Air bubbles > 10 µL downstream from the VALARD, fraction of pause time of the forward bulk flow, and the transit time of the 120 mL of air at the working chamber were recorded. The VALARD: no air bubbles > 10 µL were detected during any tested combination of air injection and bulk flow rates without pause of forward flow. The Belmont pump: air bubbles > 10 µL were detected in 60% of the tests with pause of the forward flow. The VALARD eliminates air efficiently without pause of the forward bulk flow. Further clinical trials are needed to compare the VALARD with other devices and to assess its efficiency, safety, and user friendliness.

Targeting protein-protein interaction by small molecules.

Protein-protein interactions (PPIs) are critical regulatory events in physiology and pathology, and they represent an important target space for pharmacological intervention. However, targeting PPIs with small molecules is challenging owing to the large surface area involved in protein-protein binding and the lack of obvious small-molecule-binding pockets at many protein-protein interfaces. Nonetheless, successful examples of small-molecule modulators of PPIs have been growing in recent years. This article reviews some of the recent advances in the discovery of small-molecule regulators of PPIs that involve key oncogenic proteins. Our discussion focuses on the three key modes of action for these small-molecule modulators: orthosteric inhibition, allosteric regulation, and interfacial binding/stabilization. Understanding the opportunities and challenges of these diverse mechanisms will help guide future efforts in developing small-molecule modulators against PPIs.

Exerkine ß-aminoisobutyric acid protects against atrial structural remodeling and atrial fibrillation in obesity via activating AMPK signaling and improving insulin sensitivity.

Moderate exercise decreases the risk for atrial fibrillation (AF), an effect which is probably mediated via exercise-stimulated release of exerkines. ß-Aminoisobutyric acid (BAIBA), a novel exerkine, has been reported to provide protective benefits against many cardiovascular diseases, yet its role in AF remains elusive. Herein, using a mouse model of obesity-related AF through high-fat diet (HFD) feeding, we found that 12-week drinking administration of BAIBA (170 mg/kg/day) decreased AF susceptibility in obese mice. Atrial remodeling assessment showed that BAIBA attenuated obesity-induced atrial hypertrophy and interstitial fibrosis, thereby ablating the substrate for AF. Of note, to our knowledge, this is the first report of the direct association of BAIBA and hypertrophy. BAIBA has been reported to be a key regulator of glucose and lipid metabolism, and we found that BAIBA alleviated insulin resistance in obese mice. Transcriptional analysis of metabolism-related genes showed that BAIBA increased the transcription of fatty acids metabolism-related genes in the atria of lean mice but not in that of obese mice. Mechanistic investigation showed that BAIBA stimulated AMP-activated protein kinase (AMPK) signaling in the atria of obese mice and palmitic acid (PA)-treated neonatal rat cardiomyocytes (NRCM), whereas inhibition of AMPK via Compound C attenuated BAIBA-conferred cardioprotection against hypertrophy and insulin resistance in PA-treated NRCM. Collectively, BAIBA attenuates AF susceptibility in obese mice via activated AMPK signaling and resultant improvement of insulin sensitivity, thereby providing perspectives on the potential therapeutic role of BAIBA in AF treatment.

Clinicopathological and molecular features of genome-stable colorectal cancers.

Colorectal cancers (CRCs) are traditionally divided into those with either chromosomal instability (CIN) or microsatellite instability (MSI). By utilizing TCGA data, the Laird team found a subset of CRCs, namely, genome-stable CRCs (GS CRCs), which lack both CIN and MSI. Although the molecular features of GS CRCs have been described in detail, the clinicopathological features are not well defined. A total of 437 CRCs were analyzed for copy number variation (CNV) statuses in eight genes (ARID1A, EGFR, FGFR1, KDM5B, MYBL2, MYC, SALL4, and SETDB1) using droplet-digital PCR. CRCs that showed CNV in ≤ one gene and no MSI were defined as GS-like CRCs. Clinicopathological and molecular features of GS-like CRCs were compared with those of CIN-like CRCs. GS-like CRCs comprised 4.6% of CRCs and showed a predilection toward the proximal colon, lower nuclear optical density, KRAS mutation, PIK3CA mutation, and aberrant expression of KRT7. Survival analysis showed no significant difference between the three subgroups. Through our study, the GS-like subtype was found to comprise a minor proportion of CRCs and have proclivity toward a proximal bowel location, hypochromatic tumor nuclei, aberrant KRT7 expression, and a high frequency of KRAS and PIK3CA mutations.

Prognostic significance of STING expression in solid tumor: a systematic review and meta-analysis.

Objective: Stimulator of interferon genes (STING) is a key regulator in initiating innate immune response from sensing cytosolic DNA. Recent studies have revealed that the cGAS-STING signaling pathway has a crucial role in tumor development and progression across cancer types. Herein, we conducted a meta-analysis to explore the relationship between the immunoexpression of STING and the survival outcome of patients in various solid tumors. Studies relevant to the subject were searched from PubMed, Embase, and Web of Science. Results: Eleven studies including 2,345 patients were eligible for the analysis. STING expression in tumor cells was related to improved disease-free survival/recurrence-free survival (DFS/RFS) (HR = 0.656, 95% CI = 0.455-0.946, p = 0.024) but not with overall survival (OS) (HR = 0.779, 95% CI = 0.534-1.136, p = 0.194). STING expression in stromal cells, however, did not show significant correlation with DFS/RFS and OS (HR = 0.979, 95% CI = 0.565-1.697, p-value = 0.940 and HR = 1.295, 95% CI = 0.845-1.985, p = 0.235, respectively). In a subgroup analysis, STING expression in tumor cells was associated with better DFS (HR = 0.622, 95% CI = 0.428-0.903, p = 0.012). In tumor cells, favorable DFS/RFS were also related to studies from univariate analysis and the gastrointestinal system (HR = 0.667, 95% CI = 0.482-0.923, p = 0.015 and HR = 0.566, 95% CI = 0.330-0.971, p = 0.039). Conclusions: STING expression in tumor cells is associated with favorable outcome in solid tumors. Systematic review registration: https://www.crd.york.ac.uk/prospero/, registration number: CRD42023427027.

Left bundle branch area pacing: A promising modality for cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) is recognized as the first-line management for patients with heart failure (HF) and conduction disorders. As a conventional mode for delivering CRT, biventricular pacing (BVP) improves cardiac function and reduces HF hospitalizations and mortality, but there are still limitations given the high incidence of a lack of response rates. Alternative pacing methods are needed either for primary or rescue therapy. In recent years, conduction system pacing (CSP) has emerged as a more physiological pacing modality for simultaneous stimulation of the ventricles, including His bundle pacing (HBP) and left bundle branch pacing (LBBP). CSP activates the His-Purkinje system, allowing normal ventricular stimulation. However, HBP is technically challenging with a relatively low success rate, high pacing threshold, and failure to correct distal conduction abnormalities. Therefore, LBBP stands out as a novel ideal physiological pacing modality for CRT. Several non-randomized studies compared the feasibility and safety of LBBP with BVP and concluded that LBBP is superior to BVP for delivering CRT with a narrower QRS and greater improvements in left ventricular ejection fraction (LVEF) and New York Heart Association (NYHA) functional class. Concurrently, some studies showed lower and stable pacing thresholds and greater improvement of B-type natriuretic peptide (BNP) levels, as well as better mechanical synchronization and efficiency. LBBP ensures better ventricular electromechanical resynchronization than BVP. In this review, we discuss current knowledge of LBBP, compare LBBP with BVP, and explore the potential of LBBP to serve as an alternative primary therapy to realize cardiac resynchronization.

Application of patient-centered care using guidelines of the Joint Commission on Accreditation of Healthcare Organizations in patients with acute subarachnoid hemorrhage.

OBJECTIVE: This study was designed to explore the feasibility and effectiveness of patient-centered care (PCC) on basis of guidelines of Joint Commission on Accreditation of Healthcare Organizations (JCI) in patients with acute subarachnoid hemorrhage (SAH). METHODS: A total of 180 SAH patients who received treatment in our hospital were selected as prospective research objects, and were divided into a study group (n=90) and a control group (n=90) by convenience sampling. Patients in the control group received conventional SAH-targeted care, and patients in the study group were additionally nursed with PCC on the basis of conventional SAH-targeted care. The general indicators, including Mini-Mental State Exam (MMSE) scores before and after intervention, activities of daily living (ADL), mental state, general self-efficacy scale (GSES), health knowledge, and incidence of complications were compared between the two groups. RESULTS: The length of hospital stay, the time in bed, and the expenses of hospitalization in the study group were lower than those of the control group (P<0.05). The scores of MMSE, ADL, GSES, and health knowledge in the study group were higher than those in the control group (P<0.05), and the scores of each dimension of Symptom Checklist-90 (SCL-90) and the incidence of complications in the study group were lower than those in the control group (P<0.05). CONCLUSION: PCC for SAH patients based on the guidelines of JCI can not only improve the outcomes, cognitive function, self-efficacy, negative emotions and ADL of patients, but also help enhance their awareness of the disease and reduce the incidence of complications.

Preparation of synchronized human cell extracts to study ubiquitination and degradation.

Ubiquitination and protein degradation regulate cell cycle progression in all eukaryotes. During mitosis, ubiquitination by the Anaphase-Promoting Complex/Cyclosome (APC/C) triggers sister chromatid separation and mitotic exit. The APC/C is tightly regulated by phosphorylation, ubiquitination, association of activators or inhibitors, and competitive binding of substrates. Much of our understanding of the mechanism of APC/C-dependent ubiquitination has been obtained from studies using extracts of Xenopus laevis eggs or synchronized human tissue culture cells. Here, we describe protocols to prepare extracts of synchronized human cells, and discuss experiments to use extracts for the biochemical analysis of APC/C-dependent ubiquitination.

[Influence of dental metallic materials on MR imaging].

Magnetic resonance imaging (MRI) technique is one of the most commonly used imaging diagnostic techniques for pate diseases at present.Metal and alloy are commonly used in dental practice. The artifacts on MRI caused by metal and alloy may result in attenuation of signal intensity, image distortion and signal loss, which severely influences imaging quality. So these materials confine the application of MRI on pate. In this paper, the influence of dental metallic materials on MRI is discussed. It expounds the generation and principals of MR artifacts, the influence of artifacts of metal dental prosthetic restoration, the effects of choosing different MR sequences and imaging weight on MRI, as well as how to prevent and diminish artifacts, to provide reference for clinical practice.

Regulation of Tumor-Associated Myeloid Cell Activity by CBP/EP300 Bromodomain Modulation of H3K27 Acetylation.

Myeloid-derived suppressor cells (MDSCs) are found in most cancer malignancies and support tumorigenesis by suppressing immunity and promoting tumor growth. Here we identify the bromodomain (BRD) of CBP/EP300 as a critical regulator of H3K27 acetylation (H3K27ac) in MDSCs across promoters and enhancers of pro-tumorigenic target genes. In preclinical tumor models, in vivo administration of a CBP/EP300-BRD inhibitor (CBP/EP300-BRDi) alters intratumoral MDSCs and attenuates established tumor growth in immunocompetent tumor-bearing mice, as well as in MDSC-dependent xenograft models. Inhibition of CBP/EP300-BRD redirects tumor-associated MDSCs from a suppressive to an inflammatory phenotype through downregulation of STAT pathway-related genes and inhibition of Arg1 and iNOS. Similarly, CBP/EP300-BRDi decreases differentiation and suppressive function of human MDSCs in vitro. Our findings uncover a role of CBP/EP300-BRD in intratumoral MDSCs that may be targeted therapeutically to boost anti-tumor immunity.

Enhancer Activity Requires CBP/P300 Bromodomain-Dependent Histone H3K27 Acetylation.

Acetylation of histone H3 at lysine 27 is a well-defined marker of enhancer activity. However, the functional impact of this modification at enhancers is poorly understood. Here, we use a chemical genetics approach to acutely block the function of the cAMP response element binding protein (CREB) binding protein (CBP)/P300 bromodomain in models of hematological malignancies and describe a consequent loss of H3K27Ac specifically from enhancers, despite the continued presence of CBP/P300 at chromatin. Using this approach to dissect the role of H3K27Ac at enhancers, we identify a critical role for this modification in the production of enhancer RNAs and transcription of enhancer-regulated gene networks.

Therapeutic Targeting of the CBP/p300 Bromodomain Blocks the Growth of Castration-Resistant Prostate Cancer.

Resistance invariably develops to antiandrogen therapies used to treat newly diagnosed prostate cancers, but effective treatments for castration-resistant disease remain elusive. Here, we report that the transcriptional coactivator CBP/p300 is required to maintain the growth of castration-resistant prostate cancer. To exploit this vulnerability, we developed a novel small-molecule inhibitor of the CBP/p300 bromodomain that blocks prostate cancer growth in vitro and in vivo Molecular dissection of the consequences of drug treatment revealed a critical role for CBP/p300 in histone acetylation required for the transcriptional activity of the androgen receptor and its target gene expression. Our findings offer a preclinical proof of concept for small-molecule therapies to target the CBP/p300 bromodomain as a strategy to treat castration-resistant prostate cancer. Cancer Res; 77(20); 5564-75. ©2017 AACR.

BDNF-TrkB signaling pathway is involved in pentylenetetrazole-evoked progression of epileptiform activity in hippocampal neurons in anesthetized rats.

Pentylenetetrazole (PTZ) is a widely-used convulsant used in studies of epilepsy; its subcutaneous injection generates an animal model with stable seizures. Here, we compared the ability of PTZ via the intravenous and subcutaneous routes to evoke progressive epileptiform activity in the hippocampal CA1 neurons of anesthetized rats. The involvement of the BDNF-TrkB pathway was then investigated. When PTZ was given intravenously, it induced epileptiform bursting activity at a short latency in a dose-dependent manner. However, when PTZ was given subcutaneously, it induced a slowly-developing pattern of epileptogenesis; first, generating multiple population-spike peaks, then spontaneous interictal discharge-like spike, leading to the final ictal discharge-like, highly synchronized bursting fi ring in the CA1 pyramidal layer of the hippocampus. K252a, a TrkB receptor antagonist, when given by intracerebroventricular injection, significantly reduced the probability of multiple population spike peaks induced by subcutaneous injection of PTZ, delayed the latency of spontaneous spikes, and reduced the burst frequency. Our results indicate that PTZ induces a progressive change of neuronal epileptiform activity in the hippocampus, and the BDNF-TrkB signaling pathway is mainly involved in the early phases of epileptogenesis, but not the synchronized neuronal burst activity associated with epileptic seizure in the PTZ animal model. These results provide basic insights into the changing pattern of hippocampal neuronal activity during the development of the PTZ seizure model, and establish an in vivo seizure model useful for future electrophysiological studies of epilepsy.