PubMed Health⌕ Search

Biomedical subjects

Meng Chen

Publications and source records attributed to Meng Chen.

At least 19 recordsLinked to original sources
PubMed2026

Efferocytosis regulatory factors in atherosclerosis: A preclinical systematic review.

BACKGROUND: Impaired efferocytosis is a key driver of plaque instability during atherosclerosis progression. Efficient clearance of apoptotic cells through efferocytosis relies on the coordinated action of multiple regulatory factors. METHODS: PubMed, Web of Science, ScienceDirect, OVID MEDLINE, and Scopus were searched for studies published up to February 7, 2026. Eligible preclinical studies were systematically reviewed to identify endogenous factors that regulate efferocytosis in atherosclerosis. Clinical evidence was also incorporated to enable a preliminary translational assessment of these regulatory factors. RESULTS: Thirty-five endogenous regulatory factors were identified from 36 included studies, and their functional roles across distinct stages of efferocytosis were characterized. Notably, metabolic regulators such as PKM2, PFKFB3, GLS1, and Drp1 were involved in distinct efferocytosis stages. This suggests that metabolic reprogramming may provide the metabolic support require for efficient efferocytosis and inflammation resolution. Ten factors were supported by preliminary clinical evidence consistent with preclinical data. PKM2 was the only candidate biomarker with prospective observational data. However, its independent predictive value still requires validation in multicenter prospective studies. CONCLUSIONS: This review provides a systematic synthesis of 35 endogenous efferocytosis regulators and elucidates their regulatory network in atherosclerosis based on a functional stage framework. Metabolic reprogramming is identified as a central hub linking efferocytosis efficiency to inflammation resolution. This review offers a new theoretical basis for efferocytosis-targeted intervention strategies.

Animals↗
PubMed2025

Noninvasive detection and differentiation of gastric malignancy using cell-free DNA biomarkers.

INTRODUCTION: Gastric cancer remains a major global health burden, with high mortality driven by late-stage diagnoses that limit treatment options and reduce survival. Current diagnostic methods such as endoscopy and biopsy are invasive, resource-intensive, and impractical for large-scale early detection. OBJECTIVES: This study aimed to develop and validate an ensemble machine learning model integrating four cell-free DNA (cfDNA) fragmentomic feature classes derived from 5 × whole genome sequencing (WGS) data to non-invasively differentiate malignant gastric cancer from benign gastric lesions in high-risk or symptomatic patients. METHODS: A total of 681 plasma samples were prospectively collected, comprising 329 from patients with gastric cancer or high-grade intraepithelial neoplasia (HGIN) and 352 from individuals with benign gastric conditions. The dataset was divided into a training cohort (n = 333) and a temporally independent validation cohort (n = 348). An external validation cohort of 305 participants was also included. RESULTS: The ensemble model achieved an AUROC of 0.920 in cross-validation testing on the training cohort, 0.912 in the independent validation cohort, and 0.896 (95% CI 0.860-0.932) in the external cohort. At a pre-specified prediction threshold of 0.402, the model demonstrated 93.3% sensitivity and 71.9% specificity in the validation cohort, yielding a PPV of 71.3% and an NPV of 93.5%. In the external cohort, sensitivity and specificity were 91.7% and 69.1%, respectively (PPV 75.7%, NPV 88.8%). Model scores correlated with clinical stage, tumor grade, and histopathological subtype. Approximately 71% of non-cancer patients could have been spared unnecessary endoscopy. CONCLUSIONS: The cfDNA fragmentomics-based ensemble model enables accurate, non-invasive differentiation between gastric cancer and benign gastric lesions in high-risk or symptomatic patients. This approach demonstrates strong potential as a pre-endoscopy triage tool, supporting earlier detection and more efficient use of diagnostic resources.

Humans↗
PubMed2006

Comparative immune responses of patients with chronic pulmonary diseases during the 2-year period after pneumococcal vaccination.

Antibody responses to a 23-valent pneumococcal vaccine for Streptococcus pneumoniae serotypes 6B, 14, 19F, and 23F in 84 patients with chronic pulmonary diseases over a 2-year period after vaccination were examined by using a third-generation enzyme-linked immunosorbent assay. Of these patients, 28 (31%) were low responders who had developed increases of at least twofold in the levels of serotype-specific immunoglobulin G (IgG) in sera for none of the four serotypes at 1 month after vaccination. Although no specific clinical features of low responders were evident, their prevaccination levels of IgG for all serotypes were higher than those of responders. In responders, the levels of IgG specific for serotypes 14 and 23F in sera were greatly increased 1 month after vaccination and those specific for serotypes 6B and 19F were moderately increased. In contrast, no significant increases in the levels of IgG specific for serotypes 6B, 19F, and 23F in the low responders during the same period were found, but the levels of IgG specific for serotype 14 did increase. Although a rapid decline in the levels of IgG for all serotypes in responders between 1 month and 6 months after vaccination was found, the levels of IgG specific for serotypes 14 and 23F in sera remained higher than the prevaccination levels for at least 2 years after vaccination. These data suggest the need for the revaccination of responders but not low responders among patients with chronic pulmonary diseases. Revaccination as early as 3 years postvaccination is recommended for responders to increase the reduced levels of IgG in sera, especially those specific for the weak vaccine antigens.

Antibodies, Bacterial↗
PubMed2006

Applying grazing incidence X-ray reflectometry (XRR) to characterising nanofilms on mica.

Molecularly smooth mica has hitherto not been widely used as a substrate for the X-ray reflectometry (XRR) technique. That is largely due to the difficulty of achieving flatness over a sufficiently large area of mica. Here we show that this difficulty can be overcome by slightly bending the mica substrate over an underlying cylinder; the enhanced rigidity of the bent mica sheet along the axis of the cylinder provides sufficient flatness along this axis for XRR measurements. To test this method, we have employed it to characterise three types of nanofilms on mica in air: (A) Cr-Au thin films; (B) a surface-grown zwitterionic polymer brush; and (C) a Langmuir-Blodgett (LB) phospholipid monolayer, using a table-top X-ray reflectometer. Fitting the obtained reflectivity curves with the standard Parratt algorithm allows us to extract the structural information of the nanofilms (both thickness and apparent roughness). Our simple method points to how XRR may be exploited as a useful characterisation tool for nanofilms on mica.

Journal Article↗
PubMed2006

Genome-wide expression profiling reveals EBV-associated inhibition of MHC class I expression in nasopharyngeal carcinoma.

To identify the molecular mechanisms by which EBV-associated epithelial cancers are maintained, we measured the expression of essentially all human genes and all latent EBV genes in a collection of 31 laser-captured, microdissected nasopharyngeal carcinoma (NPC) tissue samples and 10 normal nasopharyngeal tissues. Global gene expression profiles clearly distinguished tumors from normal healthy epithelium. Expression levels of six viral genes (EBNA1, EBNA2, EBNA3A, EBNA3B, LMP1, and LMP2A) were correlated among themselves and strongly inversely correlated with the expression of a large subset of host genes. Among the human genes whose inhibition was most strongly correlated with increased EBV gene expression were multiple MHC class I HLA genes involved in regulating immune response via antigen presentation. The association between EBV gene expression and inhibition of MHC class I HLA expression implies that antigen display is either directly inhibited by EBV, facilitating immune evasion by tumor cells, and/or that tumor cells with inhibited presentation are selected for their ability to sustain higher levels of EBV to take maximum advantage of EBV oncogene-mediated tumor-promoting actions. Our data clearly reflect such tumor promotion, showing that deregulation of key proteins involved in apoptosis (BCL2-related protein A1 and Fas apoptotic inhibitory molecule), cell cycle checkpoints (AKIP, SCYL1, and NIN), and metastasis (matrix metalloproteinase 1) is closely correlated with the levels of EBV gene expression in NPC.

Biopsy↗
PubMed2006

Preparation and study of polyacryamide-stabilized silver nanoparticles through a one-pot process.

A one-pot route was illustrated to synthesize stable well-dispersed silver colloids stabilized by polyacrylamide on a large scale. Reduction of silver ions and polymerization of acrylamide occurred almost simultaneously in the absence of a commonly used reducing agent and initiator. A possible mechanism for the formation of silver nanoparticles with bimodal size distribution was proposed. The structure and composition of the obtained nanoparticles were characterized carefully. Furthermore, light scattering simulation and UV-vis absorption studies confirmed that the obtained colloids were the mixture of Ag and Ag2O nanoparticles. The presence of silver oxide layers on the nanoparticle surface should be responsible for the broadening of the surface plasmon band of silver nanoparticles. Ag2O layers could be added or removed from Ag nanoparticle surfaces by the addition of HNO3, HAc, or NaCl solution to the as-obtained silver colloids.

Acrylic Resins↗
PubMed2006

Recurrence of occult pneumococcal bacteremia by an identical strain in an apparently healthy child.

This is the first report to describe an apparently healthy girl, who developed recurrent occult bacteremia by the same Streptococcus pneumoniae strain, at 11 and 15 months of age. The two separately isolated organisms were demonstrated to have the identical serotype (type 6B), antibiotic susceptibility (intermediately penicillin-resistant), genotypes of penicillin-binding proteins, and patterns of pulse-field gel electrophoresis. The serum levels of anti-type 6B antibodies showed poor responses after both bacteremic episodes, but other immunological workups did not demonstrate any abnormalities. This case indicates that occult bacteremia may recur due to an identical pneumococcal strain in an immunocompetent infant, and that early introduction of pneumococcal conjugate vaccine is necessary in Japan.

Antibodies, Bacterial↗
PubMed2006

Transcriptional regulation of yeast phospholipid biosynthetic genes.

The last several years have been witness to significant developments in understanding transcriptional regulation of the yeast phospholipid structural genes. The response of most phospholipid structural genes to inositol is now understood on a mechanistic level. The roles of specific activators and repressors are also well established. The knowledge of specific regulatory factors that bind the promoters of phospholipid structural genes serves as a foundation for understanding the role of chromatin modification complexes. Collectively, these findings present a complex picture for transcriptional regulation of the phospholipid biosynthetic genes. The INO1 gene is an ideal example of the complexity of transcriptional control and continues to serve as a model for studying transcription in general. Furthermore, transcription of the regulatory genes is also subject to complex and essential regulation. In addition, databases resulting from a plethora of genome-wide studies have identified regulatory signals that control one of the essential phospholipid biosynthetic genes, PIS1. These databases also provide significant clues for other regulatory signals that may affect phospholipid biosynthesis. Here, we have tried to present a complete summary of the transcription factors and mechanisms that regulate the phospholipid biosynthetic genes.

CDP-Diacylglycerol-Inositol 3-Phosphatidyltransfer↗
PubMed2006

Synthesis and biological evaluation of lisofylline (LSF) analogs as a potential treatment for Type 1 diabetes.

Lisofylline (LSF, 1-(5-R-hydroxyhexyl)-3,7-dimethylxanthine) is an anti-inflammatory agent that protects beta-cells from Th1 cytokine-induced dysfunction and reduces the onset of Type 1 diabetes in non-obese diabetic (NOD) mice. Due to its low potency, poor oral bioavailability, and short half-life, the widespread clinical utility of LSF may be limited. Our goal has been to develop new agents based on the LSF structural motif that resolve the potency and pharmacokinetic liabilities of LSF. In this study, we have generated a focused library of LSF analogs that maintain the side chain (5-R-hydroxyhexyl) constant, while substituting a variety of nitrogen-containing heterocyclic substructures for the xanthine moiety of LSF. This library includes the xanthine-like (5-aza-7-deazaxanthine), as well as non-xanthine-like skeletons. The LSF analogs were evaluated in a pancreatic beta-cell line for the effects on apoptosis protection and insulin release. The metabolic stability of selected compounds was also tested.

Animals↗
PubMed2006

Combined treatment with lisofylline and exendin-4 reverses autoimmune diabetes.

Type 1 diabetes mellitus (T1DM) is an autoimmune disease leading to near complete pancreatic beta-cell destruction. New evidence suggests that beta-cell regeneration is possible, but ongoing autoimmune damage prevents restoration of beta-cell mass. We tested the hypothesis that simultaneously blocking autoimmune cytokine damage and supplying a growth-promoting stimulus for beta-cells would provide a novel approach to reverse T1DM. Therefore, in this study we combined lisofylline to suppress autoimmunity and exendin-4 to enhance beta-cell proliferation for treating autoimmune-mediated diabetes in the non-obese diabetic (NOD) mouse model. We found that this combined therapy effectively reversed new-onset diabetes within a week of therapy, and even maintained euglycemia up to 145 days after treatment withdrawal. The therapeutic effect of this regimen was associated with improved beta-cell metabolism and insulin secretion, while reducing beta-cell apoptosis. It is possible that such combined therapy could become a new strategy to defeat T1DM in humans.

Animals↗
PubMed2006

Combined expression trait correlations and expression quantitative trait locus mapping.

Coordinated regulation of gene expression levels across a series of experimental conditions provides valuable information about the functions of correlated transcripts. The consideration of gene expression correlation over a time or tissue dimension has proved valuable in predicting gene function. Here, we consider correlations over a genetic dimension. In addition to identifying coregulated genes, the genetic dimension also supplies us with information about the genomic locations of putative regulatory loci. We calculated correlations among approximately 45,000 expression traits derived from 60 individuals in an F2 sample segregating for obesity and diabetes. By combining the correlation results with linkage mapping information, we were able to identify regulatory networks, make functional predictions for uncharacterized genes, and characterize novel members of known pathways. We found evidence of coordinate regulation of 174 G protein-coupled receptor protein signaling pathway expression traits. Of the 174 traits, 50 had their major LOD peak within 10 cM of a locus on Chromosome 2, and 81 others had a secondary peak in this region. We also characterized a Riken cDNA clone that showed strong correlation with stearoyl-CoA desaturase 1 expression. Experimental validation confirmed that this clone is involved in the regulation of lipid metabolism. We conclude that trait correlation combined with linkage mapping can reveal regulatory networks that would otherwise be missed if we studied only mRNA traits with statistically significant linkages in this small cross. The combined analysis is more sensitive compared with linkage mapping alone.

Animals↗
PubMed2006

Chemical and cold sensitivity of two distinct populations of TRPM8-expressing somatosensory neurons.

The cold- and menthol-sensing TRPM8 receptor has been proposed to have both nonnociceptive and nociceptive functions. However, one puzzle is how this single type of receptor may be used by somatosensory neurons to code for two distinct sensory modalities. Using acutely dissociated rat dorsal root ganglion (DRG) neurons without culture, we show that TRPM8 receptors are expressed on two distinct classes of somatosensory neurons. One class is sensitive to menthol and features nonnociceptive neuron properties, including capsaicin-insensitive, ATP-insensitive, transient acid response, and expression of TTX-sensitive sodium channels only. This class is termed the menthol-sensitive/capsaicin-insensitive neuron class (MS/CIS). The other class is also sensitive to menthol but has characteristics of nociceptive neurons including capsaicin-sensitive, ATP-sensitive, prolonged acid response, and expression of both TTX-sensitive and TTX-resistant sodium channels. This class is termed the menthol-sensitive/capsaicin-sensitive neuron class (MS/CS). The presence of these two neuron classes in acutely dissociated DRG neurons support the idea that TRPM8 receptors can have both nonnociceptive and nociceptive functions. While both neuron classes respond to menthol and cold, the overall responses induced by menthol and cold are significantly larger in MS/CIS than in MS/CS neurons. Furthermore, low concentrations of menthol produce strong selection of the MS/CIS neuron population over the MS/CS neuron population. On the other hand, the population selection becomes weaker with higher concentrations of menthol. TRPM8 current density shows significant higher in MS/CIS neurons than in MS/CS neurons, suggesting different expression levels of TRPM8 receptors between the two neuron populations, and this difference may provide a mean of selective activation of MS/CIS neurons at low stimulation intensity.

Animals↗
PubMed2006

Four new neo-clerodane diterpenoid alkaloids from Scutellaria barbata with cytotoxic activities.

Four new neo-clerodane diterpenoid alkaloids, named scutebarbatines C-F (1-4), were isolated from the whole plants of Scutellaria barbata D. DON. Their structures were elucidated by spectral analyses (UV, IR, FAB-MS, 1D-NMR and 2D-NMR). In vitro, compounds 1-4 showed significant cytotoxic activities against three human cancer cell lines, namely, HONE-1 nasopharyngeal, KB oral epidermoid carcinoma, and HT29 colorectal carcinoma cells, and gave IC(50) values in the range 3.9-7.8 muM.

Cell Proliferation↗
PubMed2005

Synthesis and self-organization of soluble monodisperse palladium nanoclusters.

Control over size and size distribution of nanoparticles has been the subject of much interest during the past decade. In the present study, a simple strategy is described for obtaining monodisperse Pd nanoparticles with size less than 5 nm and size distribution around 10%. Without size-selective precipitation but with a simple reducing agent, hypophosphite, the synthesized Pd nanoparticles can form 2D well-ordered arrays on the TEM grids. When reducing agents were changed, no obvious size change of Pd nanoparticles was observed within experimental errors but the size distribution varied dramatically. In addition, stability, self-organized pattern, and solubility can be controlled by changing the capping agent. The present route is very simple and reproducible, and further study on the properties of the Pd nanoparticles is underway.

Journal Article↗
PubMed2005

Substance P-driven feed-forward inhibitory activity in the mammalian spinal cord.

In mammals, somatosensory input activates feedback and feed-forward inhibitory circuits within the spinal cord dorsal horn to modulate sensory processing and thereby affecting sensory perception by the brain. Conventionally, feedback and feed-forward inhibitory activity evoked by somatosensory input to the dorsal horn is believed to be driven by glutamate, the principle excitatory neurotransmitter in primary afferent fibers. Substance P (SP), the prototypic neuropeptide released from primary afferent fibers to the dorsal horn, is regarded as a pain substance in the mammalian somatosensory system due to its action on nociceptive projection neurons. Here we report that endogenous SP drives a novel form of feed-forward inhibitory activity in the dorsal horn. The SP-driven feed-forward inhibitory activity is long-lasting and has a temporal phase distinct from glutamate-driven feed-forward inhibitory activity. Compromising SP-driven feed-forward inhibitory activity results in behavioral sensitization. Our findings reveal a fundamental role of SP in recruiting inhibitory activity for sensory processing, which may have important therapeutic implications in treating pathological pain conditions using SP receptors as targets.

Animals↗
PubMed2005

Determination of riboflavin by high-performance liquid chromatography with riboflavin-depleted urine as calibration and control matrix.

A simple method, exposure to natural-light, was developed to remove riboflavin from urine to enhance its use as the biological matrix for the preparation of calibration and control samples. Riboflavin-depleted urine containing less than 1 ng/ml of riboflavin was used to validate a high-performance liquid chromatography with fluorescence detection method for the determination of urinary riboflavin. The linearity of the assay (r2=0.999) was acceptable over the range of 10-5000 ng/ml. The intra-assay and inter-assay CVs were 3.3% and 9%, respectively. Subsequent stability studies found that urine riboflavin was stable for up to 6 months at 4 or -20 degrees C.

Adult↗
PubMed2005

Regulation of phytochrome B nuclear localization through light-dependent unmasking of nuclear-localization signals.

Phytochromes are red and far-red photoreceptors that regulate plant growth and development in response to environmental light cues. Phytochromes exist in two photo-interconvertible conformational states: an inactive Pr form and an active Pfr form. The alteration of phytochromes' subcellular location functions as a major regulatory mechanism of their biological activities. Whereas phytochromes in the Pr form localize in the cytoplasm, phytochromes in the Pfr form accumulate in the nucleus, where they interact with transcription factors to regulate gene expression. The molecular details of the regulation of phytochrome translocation by light are poorly understood. Using Arabidopsis phyB as a model, we demonstrate that the C-terminal PAS-related domain (PRD) is both necessary and sufficient for phyB nuclear import and that the entire C terminus is required for nuclear-body (NB) localization. We also show that phyB's N-terminal bilin lyase domain (BLD) and PHY domain interact directly with the PRD in a light-dependent manner. In vivo localization studies indicate that BLD-PHY is sufficient to regulate phyB's nuclear accumulation. For phyB nuclear localization, our results suggest a molecular mechanism in which the nuclear-localization signal in the PRD is masked by interactions with phyB's chromophore-attachment domains and unmasked by light-dependent conformational changes.

Arabidopsis↗