Polyribonucleotide nucleotidyltransferase 1 participates in metabolic-associated fatty liver disease pathogenesis by affecting lipid metabolism and mitochondrial homeostasis.

OBJECTIVE: Metabolic-associated fatty liver disease (MAFLD) represents one of the most prevalent chronic liver conditions worldwide, but its precise pathogenesis remains unclear. This research endeavors to elucidate the involvement and molecular mechanisms of polyribonucleotide nucleotidyltransferase 1 (PNPT1) in the progression of MAFLD. METHODS: The study employed western blot and qRT-PCR to evaluate PNPT1 levels in liver specimens from individuals diagnosed with MAFLD and in mouse models subjected to a high-fat diet. Cellular studies investigated the effects of PNPT1 on lipid metabolism, apoptosis, and mitochondrial stability in hepatocytes. Immunofluorescence was utilized to track the subcellular movement of PNPT1 under high lipid conditions. RNA immunoprecipitation and functional assays were conducted to identify interactions between PNPT1 and Mcl-1 mRNA. The role of PPARα as an upstream transcriptional regulator of PNPT1 was investigated. Recombinant adenoviral vectors were utilized to modulate PNPT1 expression in vivo. RESULTS: PNPT1 was found to be markedly reduced in liver tissues from MAFLD patients and HFD mice. In vitro, PNPT1 directly regulated hepatic lipid metabolism, apoptosis, and mitochondrial stability. Under conditions of elevated lipids, PNPT1 relocated from mitochondria to cytoplasm, modifying its physiological functions. RNA immunoprecipitation revealed that the KH and S1 domains of PNPT1 bind to and degrade Mcl-1 mRNA, which in turn affects mitochondrial permeability. The transcriptional regulator PPARα was identified as a significant influencer of PNPT1, impacting both its expression and subsequent cellular functions. Alterations in PNPT1 expression were directly correlated with the progression of MAFLD in mice. CONCLUSIONS: The study confirms the pivotal function of PNPT1 in the development of MAFLD through its interactions with Mcl-1 and its regulatory effects on lipid metabolism and mitochondrial stability. These insights highlight the intricate association between PNPT1 and MAFLD, shedding light on its molecular pathways and presenting a potential new therapeutic avenue for MAFLD management.

ZNF460-mediated upregulation of APCDD1L-DT promotes cholangiocarcinoma development by inhibiting the ubiquitin-mediated degradation of DVL2.

Cholangiocarcinoma (CCA), known for its aggressive nature, poses a formidable challenge in the current medical landscape, particularly in targeted therapies. Against this backdrop, long non-coding RNAs (lncRNAs) have captured the attention of researchers. These unique RNAs are believed to play pivotal roles in various cancers, offering promising avenues for the development of more effective treatment strategies. Previous studies have substantiated the aberrant expression of the APCDD1L-DT in numerous human tumors, demonstrating its positive regulatory roles in disease progression. Nevertheless, the biological functions of APCDD1L-DT in CCA are still not fully understood. This study marks the inaugural documentation of APCDD1L-DT exhibiting aberrant expression in CCA specimen, establishing a close correlation with the TNM staging of tumor patients. Furthermore, suppressing APCDD1L-DT expression hinders both the viability and motility of tumor cells. Mechanistically, the abnormal activation of the transcription factor ZNF460 positively regulated APCDD1L-DT expression in CCA. This activation, in turn, propels the abnormal activation of the Wnt pathway, fostering tumor development by impeding the ubiquitin-mediated degradation of DVL2. Broadly speaking, this study provides auspicious perspectives for comprehending CCA and furnishes support for addressing this daunting malignancy.

The Quantitative Evaluation of Automatic Segmentation in Lumbar Magnetic Resonance Images.

OBJECTIVE: This study aims to overcome challenges in lumbar spine imaging, particularly lumbar spinal stenosis, by developing an automated segmentation model using advanced techniques. Traditional manual measurement and lesion detection methods are limited by subjectivity and inefficiency. The objective is to create an accurate and automated segmentation model that identifies anatomical structures in lumbar spine magnetic resonance imaging scans. METHODS: Leveraging a dataset of 539 lumbar spinal stenosis patients, the study utilizes the residual U-Net for semantic segmentation in sagittal and axial lumbar spine magnetic resonance images. The model, trained to recognize specific tissue categories, employs a geometry algorithm for anatomical structure quantification. Validation metrics, like Intersection over Union (IOU) and Dice coefficients, validate the residual U-Net's segmentation accuracy. A novel rotation matrix approach is introduced for detecting bulging discs, assessing dural sac compression, and measuring yellow ligament thickness. RESULTS: The residual U-Net achieves high precision in segmenting lumbar spine structures, with mean IOU values ranging from 0.82 to 0.93 across various tissue categories and views. The automated quantification system provides measurements for intervertebral disc dimensions, dural sac diameter, yellow ligament thickness, and disc hydration. Consistency between training and testing datasets assures the robustness of automated measurements. CONCLUSION: Automated lumbar spine segmentation with residual U-Net and deep learning exhibits high precision in identifying anatomical structures, facilitating efficient quantification in lumbar spinal stenosis cases. The introduction of a rotation matrix enhances lesion detection, promising improved diagnostic accuracy, and supporting treatment decisions for lumbar spinal stenosis patients.

Research progress and applications of epigenetic biomarkers in cancer.

Epigenetic changes are heritable changes in gene expression without changes in the nucleotide sequence of genes. Epigenetic changes play an important role in the development of cancer and in the process of malignancy metastasis. Previous studies have shown that abnormal epigenetic changes can be used as biomarkers for disease status and disease prediction. The reversibility and controllability of epigenetic modification changes also provide new strategies for early disease prevention and treatment. In addition, corresponding drug development has also reached the clinical stage. In this paper, we will discuss the recent progress and application status of tumor epigenetic biomarkers from three perspectives: DNA methylation, non-coding RNA, and histone modification, in order to provide new opportunities for additional tumor research and applications.

Circ_0007534 promotes cholangiocarcinoma stemness and resistance to anoikis through DDX3X-mediated positive feedback regulation of parental gene DDX42.

Cholangiocarcinoma (CCA) is a malignancy with an extremely poor prognosis, and much remains unknown about its pathogenesis and treatment modalities. Circular RNA (circRNA) has been proven to play regulatory roles in various tumorigenesis, yet its potential function and mechanism in cholangiocarcinoma require further investigation. This study is the first to identify the aberrant expression and functional role of a novel circRNA, circ_0007534, derived from the DDX42 gene, in cholangiocarcinoma. Compared to the normal control group, the expression of circ_0007534 was significantly elevated in the tissues and cells with CCA and that high expression correlated with lymph node invasion and poor prognosis. Functional experiments indicated that downregulating circ_0007534 markedly inhibited the proliferation, migration, invasion, stemness, and anti-anoikis ability of CCA cells, as well as the tumor growth and liver and lung metastasis in nude mice. Mechanistic studies revealed that DDX42, as the parent gene of circ_0007534, can mutually regulate each other's expression. Predominantly located in the cytoplasm, circ_0007534 can form a complex with the RNA-binding protein DDX3X, which enhances the stability of DDX42 mRNA, thereby upregulating the expression of DDX42. This creates a positive feedback loop among the three, collectively promoting the progression of cholangiocarcinoma. In conclusion, this study sheds light on the pivotal role and molecular mechanism of circ_0007534 in the development of CCA, offering potential new targets for early diagnosis and treatment.

Mechanism for transmission and pathogenesis of carbapenem-resistant Enterobacterales harboring the carbapenemase IMP and clinical countermeasures.

Carbapenem-resistant Enterobacterales (CRE) are some of the most important pathogens causing infections, which can be challenging to treat. We identified four blaIMP-carrying CRE isolates and collected clinical data. The transferability and stability of the plasmid were verified by conjugation, successive passaging, and plasmid elimination assays. The IncC blaIMP-4-carrying pIMP4-ECL42 plasmid was successfully transferred into the recipient strain, and the high expression of traD may have facilitated the conjugation transfer of the plasmid. Interestingly, the plasmid showed strong stability in clinical isolates. Whole-genome sequencing was performed on all isolates. We assessed the sequence similarity of blaIMP -harboring plasmid from our institution and compared it to plasmids for which sequence data are publicly available. We found that four blaIMP-carrying CRE belonged to four different sequence types. The checkerboard technique and time-kill assays were used to investigate the best antimicrobial therapies for blaIMP-carrying CRE. The time-kill assay showed that the imipenem of 1× minimum inhibitory concentration (MIC) alone had the bactericidal or bacteriostatic effect against IMP-producing strains at 4-12 h in vitro. Moreover, the combination of tigecycline (0.5/1/2 × MIC) and imipenem (0.5/1 × MIC) showed a bactericidal effect against the blaIMP-26-carrying CRECL60 strain.IMPORTANCECarbapenem-resistant Enterobacterales (CRE) are an urgent public health threat, and infections caused by these microorganisms are often associated with high mortality and limited treatment options. This study aimed to determine the clinical features, molecular characteristics, and plasmid transmissible mechanisms of blaIMP carriage as well as to provide a potential treatment option. Here, we demonstrated that conjugated transfer of the IncC blaIMP-4-carrying plasmid promotes plasmid stability, so inhibition of conjugated transfer and enhanced plasmid loss may be potential ways to suppress the persistence of this plasmid. The imipenem alone or tigecycline-imipenem combination showed a good bactericidal effect against IMP-producing strains. In particular, our study revealed that imipenem alone or tigecycline-imipenem combination may be a potential therapeutic option for patients who are infected with IMP-producing strains. Our study supports further trials of appropriate antibiotics to determine optimal treatment and emphasizes the importance of continued monitoring of IMP-producing strains in the future.

Ferroptosis: New Strategies and Ideas for the Treatment of Pancreatic Ductal Adenocarcinoma.

Pancreatic cancer is a malignancy that affects the digestive tract and has a low 5-year survival rate of lower than 15%. Owing to its genetic mutation and metabolic complexity, pancreatic cancer is difficult to treat with surgical resection, radiotherapy, and chemotherapy. The predominant modality of pancreatic cancer is pancreatic ductal adenocarcinoma (PDAC), primarily attributed to mutations in KRAS gene. Ferroptosis, an iron-mediated reactive oxygen species (ROS)-elevated nonapoptotic cell death caused by lipid peroxidation, is distinct from any other known type of cell death. Ferroptosis is closely related to the occurrence and progression of different types of cancers, including PDAC. Previous research has demonstrated that ferroptosis not only triggers cell death in PDAC and hampers tumor growth but also enhances the effectiveness of antitumor medications. In our review, we mainly focus on the core mechanism of ferroptosis, reveal its interrelationship with PDAC, and illustrate the progress of ferroptosis in different treatment methods of PDAC.

Circular RNAs in pancreatic cancer progression.

Pancreatic cancer (PC), typically diagnosed at relatively advanced stages with poor prognosis, is a dominant cause of cancer-related deaths worldwide. Accumulating evidence demonstrates that circular RNAs (circRNAs) are abnormally expressed in diverse tumors and affect tumorigenesis and progression. In this article, we examine the roles of circRNAs in regulation of PC progression. Additionally, circRNAs enriched in exosomes could be transferred among PC cells to modulate malignancy. Characterization of regulatory mechanisms involving circRNAs in general and PC specifically will enable earlier detection and potential development of therapeutic strategies.

Increased Expression and Amplification of blaKPC-2 Contributes to Resistance to Ceftazidime/Avibactam in a Sequence Type 11 Carbapenem-Resistant Klebsiella pneumoniae Strain.

Ceftazidime/avibactam (CAZ/AVI) is regarded as an effective alternative antibiotic for the clinical treatment of Klebsiella pneumoniae carbapenemase (KPC)-producing isolates. As resistance has been reported in some strains, it is critical to understand the key mechanisms contributing to the acquired resistance to CAZ/AVI. From January 2018 to April 2020, 127 KPC-producing carbapenem-resistant Klebsiella pneumoniae strains (CRKPs) were isolated at a university hospital in Chongqing, China, and 25 strains showed reduced susceptibility to CAZ/AVI. All reduced-susceptibility CRKPs were deficient in Ompk35 and Ompk36 porins, and 24 strains had a premature termination at amino acid position 63 in Ompk35 and 134 to 135 glycine and aspartic acid (GD) insertion in OmpK36, while the blaKPC-2 expression level showed no significant difference compared to that of strain BAA-1705. Four reduced-susceptibility strains evolved resistance under selective pressure of CAZ/AVI with the blaKPC-2 expression level increased, and two of these strains had mutations in the Ω-loop. The study found a strain of CRKP55 with changes in the resistance phenotype during conjugation, evolving from reduced sensitivity to high-level resistance to CAZ/AVI. Through plasmid sequencing and reverse transcription-quantitative PCR, it was speculated that insertion sequence (IS)26-mediated blaKPC-2 gene amplification caused the MIC value change in the conjugant JKP55. Our findings illustrated the potential of CAZ/AVI resistance under antibiotic stress and demonstrated that IS26 may mediate blaKPC-2 replication transposition, leading to high-level resistance during horizontal gene transfer. Investigation of CAZ/AVI resistance mechanisms may offer a unique opportunity to study the horizontal evolutionary trajectories of K. pneumoniae high-risk clones. IMPORTANCE Klebsiella pneumoniae carbapenemase (KPC) production is the most common mechanism of K. pneumoniae resistance to carbapenems in China. Currently, CAZ/AVI is considered a potential alternative therapeutic option for infections caused by these isolates. However, there have been increasing reports of resistant or reduced-sensitivity strains since the approval of this agent. In this study, resistance to CAZ/AVI was induced under drug-selective pressure and was caused by blaKPC-2 overexpression and/or substitutions in the Ω-loop of KPC. Additionally, it was demonstrated that a conjugative plasmid carrying blaKPC-2 could transfer horizontally between species, and perhaps, IS26-derived tandem amplification of blaKPC-2 during this period led to high-level resistance to CAZ/AVI. Our research suggests that IS26-mediated resistance evolution may have important implications in guiding clinical antibiotic use.

An Outbreak of Carbapenem-Resistant Klebsiella pneumoniae in an Intensive Care Unit of a Major Teaching Hospital in Chongqing, China.

Background: Due to the critical condition and poor immunity of patients, the intensive care unit (ICU) has always been the main hospital source of multidrug-resistant bacteria. In recent years, with the large-scale use of antibiotics, the detection rate and mortality of carbapenem-resistant Klebsiella pneumoniae (CRKP) have gradually increased. This study explores the molecular characteristics and prevalence of CRKP isolated from the ICU ward of a tertiary hospital in China. Methods: A total of 51 non-duplicated CRKP samples isolated from the ICU were collected from July 2018-July 2020. The enzyme production of the strains was preliminarily screened by carbapenemase phenotypic test, and drug-resistant and virulence genes were detected by PCR. The transferability of plasmid was verified by conjugation test. The minimal inhibitory concentration (MIC) was determined by microbroth dilution method and genetic diversity was detected by multilocus sequence typing and pulsed-field gel electrophoresis. Results: blaKPC-2 was the only carbapenemase detected. The major virulence genes were uge (100%), mrkD (94.1%), kpn (94.1%), and fim-H (72.5%), while wcag, ironB, alls and magA genes were not detected. One sequence type ST1373 strain, hypervirulent K. pneumoniae (hvKP), was detected. CRKP strains were highly resistant to quinolones, cephalosporins, aminoglycosides, and polymyxin, but susceptive to tigecycline and ceftazidime-avibactam. The success rate of conjugation was 12.2%, indicating the horizontal transfer of blaKPC-2 . Homology analysis showed that there was a clonal transmission of ST11 CRKP in the ICU of our hospital. Conclusion: The present study showed the outbreak and dissemination in ICU were caused by ST11 CRKP, which were KPC-2 producers, and simultaneously, also carried some virulence genes. ST11 CRKP persisted in the ward for a long time and spread among different areas. Due to the widespread dispersal of the transferable blaKPC-2 plasmid, the hospital should promptly adopt effective surveillance and strict infection control strategies to prevent the further spread of CRKP. Ceftazidime-avibactam showed high effectiveness against CRKP and could be used for the treatment of ICU infections.

Carbapenemase Production and Epidemiological Characteristics of Carbapenem-Resistant Klebsiella pneumoniae in Western Chongqing, China.

Background: This study aimed to determine the molecular characteristics of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates in a hospital in western Chongqing, southwestern China. Methods: A total of 127 unique CRKP isolates were collected from the Yongchuan Hospital of Chongqing Medical University, identified using a VITEK-2 compact system, and subjected to microbroth dilution to determine the minimal inhibitory concentration. Enterobacteriaceae intergenic repeat consensus polymerase chain reaction and multilocus sequence typing were used to analyze the homology among the isolates. Genetic information, including resistance and virulence genes, was assessed using polymerase chain reaction. The genomic features of the CRKP carrying gene blaKPC-2 were detected using whole-genome sequencing. Results: ST11 was the dominant sequence type in the homology comparison. The resistance rate to ceftazidime-avibactam in children was much higher than that in adults as was the detection rate of the resistance gene blaNDM (p < 0.0001). Virulence genes such as mrkD (97.6%), uge (96.9%), kpn (96.9%), and fim-H (84.3%) had high detection rates. IncF (57.5%) was the major replicon plasmid detected, and sequencing showed that the CRKP063 genome contained two plasmids. The plasmid carrying blaKPC-2, which mediates carbapenem resistance, was located on the 359,625 base pair plasmid IncFII, together with virulence factors, plasmid replication protein (rep B), stabilizing protein (par A), and type IV secretion system (T4SS) proteins that mediate plasmid conjugation transfer. Conclusion: Our study aids in understanding the prevalence of CRKP in this hospital and the significant differences between children and adults, thus providing new ideas for clinical empirical use of antibiotics.

Microbial Characteristics and Genomic Analysis of an ST11 Carbapenem-Resistant Klebsiella pneumoniae Strain Carrying bla KPC-2 Conjugative Drug-Resistant Plasmid.

BACKGROUND: The sequence type 11 (ST11) carbapenem-resistant Klebsiella pneumoniae (CRKP) carrying bla KPC-2 has been widespread all over the world, and it has been reported frequently in China. The bla KPC-2 located on the mobile genetic element brings tremendous pressure to control the spread and outbreak of resistant bacteria. Whole-genome sequencing (WGS) technology can comprehensively and in-depth display the molecular characteristics of drug-resistant bacteria, providing a basis for evaluating the genetic diversity within the CRKP genome. METHODS: The ST11 CRKP in this study was collected in the intensive care unit of a major teaching hospital. PCR and Sanger sequencing confirmed the existence of bla KPC-2. The AST-GN card and the microbroth dilution test were used for antimicrobial susceptibility testing. The transferability of plasmid was verified by a conjugation test. The whole genome is sequenced using the Illumina HiSeq short-read and Oxford Nanopore long-read sequencing technology. RESULTS: The studied strain was named CRKP63, which is a multi-drug resistance bacteria, which carries bla KPC-2 and bla SHV-182. Its genome consists of a circular chromosome of 5,374,207 bp and an IncFII plasmid named pKPC-063001 of 359,625 bp. In the drug-resistant plasmid pKPC-063001, the key carbapenem resistance gene bla KPC-2 was located in the genetic context with insertion sequence ISKpn27 upstream and ISKpn6 downstream and bracketed by IS26. The three copies of the IS26-ISKpn27-bla KPC-2-ISKpn6-IS26 unit were present in tandem. bla KPC-2 can be transferred horizontally between other species by conjugation, the complete type IV secretion system (T4SS) structure helps to improve the adaptability of bacteria to the external environment, strengthen the existence of drug-resistant bacteria, and accelerate the spread of drug resistance. CONCLUSION: High-throughput sequencing has discovered the different surrounding environments of bla KPC-2, which provides a new idea for further revealing the transmission and inheritance of bla KPC-2 at the molecular level. In order to control the further spread and prevalence of drug-resistant bacteria, we should pay close attention to the changes in the genetic environment of bla KPC-2 and further study the transcription and expression of T4SS.