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Biomedical subjects

Ming Li

Publications and source records attributed to Ming Li.

18 recordsLinked to original sources

Exploring the Melanoma and Pancreatic Cancer Phenotype of a Potential CDKN2A Founder Variant, I49T (c.146T>C; p.Ile49Thr), in Individuals of Predominantly Mexican Ancestry.

PURPOSE: Pathogenic/likely pathogenic variants (P/LPVs) in the CDKN2A gene cause an increased risk of melanoma (MEL) and pancreatic cancer (PANC). The CDKN2A variant I49T (c.146T>C), reported to be recurrent in Hispanics, has conflicting pathogenicity classifications at laboratories, affecting clinical care. Multiple genetics clinics collaborated to explore cancers associated with I49T. METHODS: Institutional clinical databases were queried for the CDKN2A variants, I49T, known P/LPVs, and c.-2G>A (a benign variant [BV]), and history of PANC and MEL was abstracted. A combination of statistical tests was used to investigate cancer history associations. RESULTS: Data on 203 individuals, with qualifying CDKN2A variants detected on multigene testing between 2012 and 2023, were analyzed (I49T, n = 101; known CDKN2A P/LPVs, n = 57; BV, n = 45). Those with I49T were 91% less likely to have MEL than known CDKN2A P/LPVs (odd ratio [OR] = 0.089 [95% CI, 0.031 to 0.025]; P < .001) and were also less likely to have PANC (OR = 0.45 [95% CI, 0.14 to 1.41]; P = .17). However, mean age at PANC diagnosis for I49T was 56.0 years, significantly younger than known CDKN2A P/LPVs (&#x3bc; = 71.0 years; P = .026). CONCLUSION: In the largest I49T study to date to our knowledge, MEL was significantly less frequent compared with known CDKN2A P/LPVs. Although a nonsignificant trend was observed for less PANC in I49T than known P/LPVs, individuals with I49T presented with PANC at a significantly younger age than those with known CDKN2A P/LPVs. The presence of I49T in Hispanics of mostly Mexican ancestry supports that it is a founder variant, relevant to understanding cancer risk in a large proportion of Hispanics in the United States.

Humans

Shared ligand-blocking mechanism but distinct conformational modulation by &#x3b1;5-targeting antibodies BIIG2 and MINT1526A.

Integrins are heterodimeric receptors important for cell adhesion and signaling. Integrin &#x3b1;5&#x3b2;1 is a key mediator of angiogenesis and its dysregulation is associated with tumor progression and metastasis. Despite numerous efforts, &#x3b1;5&#x3b2;1-targeting therapeutics have been unsuccessful due to poor efficacy and off-target effects. A contributing factor is our limited understanding of how integrin conformation influences interactions with therapeutics. Using cell-based functional assays, patient-derived xenografts, biophysics, X-ray crystallography, and electron microscopy, we shed light on these relationships by characterizing two anti-&#x3b1;5&#x3b2;1 antibodies, BIIG2 and MINT1526A. We show that both antibodies bind &#x3b1;5&#x3b2;1 with nanomolar affinity, reduce tube formation in vitro, and bind overlapping epitopes that block fibronectin binding. However, using electron microscopy, we reveal that while BIIG2 binding does not substantially alter the conformational states, MINT1526A preferentially recognizes the bent conformation and restricts the conformational ensemble. These insights can guide which aspects to prioritize to improve the design of future integrin-targeted therapeutics.

angiogenesis

A Novel Homozygous Mutation in ARL2BP Causes Multiple Morphological Abnormalities of the Flagella and Primary Ciliary Dyskinesia.

Primary ciliary dyskinesia (PCD) and multiple morphological abnormalities of the sperm flagella (MMAF) frequently co-occur in male infertility. However, the genetic basis of this syndromic presentation remains unclear. Using whole-exome sequencing, we identified a novel homozygous ARL2BP splice-site mutation (c.294-2A>G) in a 23-year-old infertile male from a consanguineous family who presented with syndromic PCD and MMAF. This variant causes aberrant pre-mRNA splicing and triggers nonsense-mediated mRNA decay, resulting in the complete absence of ARL2BP protein expression. Transmission electron microscopy revealed extensive disorganization of flagellar axonemes with consistent central pair (CP) microtubule depletion and disorganization of peripheral doublets. Immunofluorescence confirmed a severe deficiency of the CP protein SPAG6 in the sperm flagella. Notably, the patient presented without retinal symptoms. Given that ARL2BP-related retinitis pigmentosa generally emerges during the third decade, long-term ophthalmological follow-up is essential to detect delayed-onset retinal degeneration. In conclusion, these findings confirm ARL2BP as a causative gene for both PCD and MMAF, expanding the genotypic and phenotypic spectrum of ciliopathies.

Humans

Quantitative assessment of the fingerprint evidential value using machine learning.

Fingerprints as physical evidence have long supported criminal investigation and adjudication. In practice, however, fingerprint identification relies mainly on examiners' experience. Furthermore, expert opinions tend to be categorical, even though the opinions with the same conclusion could differ substantially in evidential strength. To quantitatively assess fingerprint evidential value, this study proposes a machine learning-based framework as an interpretable decision-support tool. A lightweight residual one-dimensional convolutional neural network was constructed, incorporating channel recalibration and a similarity-driven attention mechanism to learn adaptive contribution weights for different matched minutiae (minutiae for short). Controlled experiments revealed that the predicted evidential value increased with the number of minutiae and was significantly influenced by the quality of minutiae. With 10 minutiae, the mean predicted scores were 4.49, 7.00, and 9.09 for blurred, moderately blurred, and clear minutiae, respectively. Multiple regression analysis indicated that replacing a pair of blurred minutiae with a pair of clear minutiae increased the score by 0.492, whereas replacing it with a pair of moderately blurred minutiae increased the score by only 0.216. By mapping predicted scores to graded levels of evidential strength, the framework contributes to a paradigm shift from categorical expert opinions to graded ones, helping courts evaluate fingerprint evidence more scientifically.

Humans

Genome-wide DNA methylation analysis revealed epigenetic mechanism underlying end-stage renal disease.

End-stage renal disease (ESRD) remains a major clinical challenge with high morbidity and mortality, and its molecular mechanisms, particularly those shared among diverse primary kidney diseases during progression to ESRD, have not been studied. Here we conduct a large-scale two-stage epigenome-wide association study of ESRD in two independent cohorts consisting of 704 controls and 1031 ESRD cases. We identify 52 ESRD-associated differentially methylated CpG positions (ESRD DMPs) showing consistent association between the two cohorts and across diverse kidney diseases, implicating 144 candidate genes enriched in inflammatory and immune pathways. Five of the 52 DMPs are associated with ESRD complications, and seven with renal function decline in early-stage chronic kidney disease, demonstrating their potential as prognostic biomarkers for ESRD and its complications. Our findings highlight inflammation, immune dysregulation, and renal fibrosis as shared epigenetic drivers of ESRD progression, and identify biomarkers with potential utility for risk stratification and therapeutic intervention.

Humans

AI proteomics: from protein identification to virtual cells.

Artificial intelligence (AI) is transforming scientific research, including proteomics. In this Perspective, we highlight key mass spectrometry (MS)-based proteomics areas where AI is driving innovation, ranging from protein identification to building AI virtual cells. These include improving peptide and protein identification and quantification; characterizing protein-protein interactions and protein complexes; advancing spatial and perturbation proteomics; integrating multi-omics data; and, ultimately, enabling AI virtual cells. Finally, we call for global collaboration among data producers, data consumers and other stakeholders to establish an AI-friendly ecosystem for MS-based proteomics, laying the foundation for transformative advancements in proteomics driven by AI.

Proteomics

CRISPR-Cas regulates expression of embedded anti-phage defence systems.

Bacteria utilize diverse defence systems to protect against harmful foreign DNA such as bacteriophages1,2, but how these systems coordinate with each other remains poorly understood. Here we uncover CRISIS (CRISPR-supervised immune system), a widespread regulatory paradigm whereby type I CRISPR-Cas loci embed and transcriptionally modulate diverse innate defences. Small non-canonical CRISPR RNA (crRNA)-like RNAs guide the I-C CRISPR-associated complex for antiviral defence (Cascade) effector complex to inhibit promoters of diverse immune cassettes-including composite multi-system clusters-enabling their basal expression for antiviral activity while mitigating fitness costs associated with hyperactivation, such as host growth impairment or exclusion of beneficial plasmids. When CRISPR-Cas is compromised by mutation or anti-CRISPR proteins, there is a burst in transcription of these embedded defence systems, leading to higher-level innate immunity at the expense of host fitness. Together, adaptive CRISPR-Cas systems orchestrate diverse innate immune systems into a layered defence network, comprising a prokaryotic 'immunity guard' strategy.

Bacteriophages

CRISPR-mediated intronic knock-in of pre-amiRNA enables targeted gene silencing.

This study introduces an intronic artificial microRNA (IamiRNA) strategy that combines CRISPR-Cas9-mediated knock-in with endogenous miRNA processing for targeted gene silencing in plants. By inserting amiRNA precursors into introns of endogenous genes, this approach enables effective, tissue-specific gene silencing without persistent transgene expression, offering a promising tool for functional genomics and crop improvement.

Introns

Endobronchial Ultrasound-Guided Biopsy-Derived Lung Cancer Models: A Platform for Precision Therapy.

BACKGROUND: Endobronchial ultrasound-guided transbronchial needle aspiration is used for clinical diagnosis and staging in patients with lung cancer. Nevertheless, establishing patient-derived preclinical models using needle biopsy samples remains challenging. This study describes the establishment and utility of patient-derived organoid (PDO) from endobronchial ultrasound-guided (EBUS) specimens and EBUS patient-derived xenograft (PDX). METHODS: A total of 175 EBUS specimens were used to establish PDO and PDX. "Stable establishment" organoids with passage numbers of 10 or greater were used for genomic, transcriptome, and pathologic assessment. Drug sensitivity of EBUS organoids and PDX tumors were compared with those of the matched patient. Drug screening was performed using stably established organoid models. RESULTS: We successfully established a total of 20 EBUS organoids: six EBUS-PDOs and 14 EBUS-xenograft derived organoids. These stable cancer organoid models were validated for cancer cell enrichment and pathologic assessment. Pathologic findings, exome, and transcriptome analysis found a high correlation between EBUS organoids and parental samples. EBUS organoids and PDX indicated consistent drug response patterns with their corresponding patients. A drug screening conducted on an EBUS organoid led to the discovery of potent activity of trametinib to a rare MAP2K1 K57N mutation. CONCLUSIONS: EBUS-PDO and -xenograft&#x2012;derived organoids are good options to generate stable organoids in patients with advanced stage lung cancer. The models were consistent with the genetic and pathologic features of patient tumors, and the patient's responses to treatment, supporting their utility for novel therapeutic research.

Humans

Centromere protein I facilitates breast cancer tumorigenesis and disease progression through modulation of Wnt/&#x3b2;-Catenin signaling.

BACKGROUND: Breast cancer (BCa) is a major contributor to female mortality worldwide. Treatment resistance and tumor heterogeneity contribute to the lack of effective therapeutic targets, posing a significant challenge in BCa management. CENPI, a core centromere protein involved in chromosome segregation, has emerging evidence implicating it in oncogenesis across diverse malignancies. However, its functional and molecular mechanisms in BCa remain unclear. METHODS: We analyzed CENPI expression and its clinical significance by using the BCa dataset from the Cancer Genome Atlas (TCGA) and immunohistochemical staining of 3 human BCa tissue samples. Cellular functional assays and mice xenograft models were utilized to assess the effects of CENPI on BCa growth. RNA sequencing combined with bioinformatics analysis was conducted to elucidate the molecular mechanisms underlying CENPI function, with further validation through Western blotting, immunofluorescence, and TOP/FOP flash assays. RESULTS: CENPI was aberrantly overexpressed in BCa, with elevated expression levels strongly associated with disease progression and poor prognosis. Functional assays demonstrated that CENPI significantly promoted breast carcinogenesis in both cellular and animal models. Mechanistically, CENPI increased BCa progression and malignant phenotypes by modulating the Wnt/&#x3b2;-catenin axis. CONCLUSIONS: CENPI is a critical oncogene in BCa, driving tumorigenesis and disease progression via the Wnt/&#x3b2;-catenin axis, which represents a promising biomarker and therapeutic target for BCa.

Breast cancer

Shared ligand-blocking mechanism but distinct conformational modulation by &#x3b1;5-targeting antibodies BIIG2 and MINT1526A.

Integrins are heterodimeric receptors important for cell adhesion and signaling. Integrin &#x3b1;5&#x3b2;1 is a key mediator of angiogenesis and its dysregulation is associated with tumor progression and metastasis. Despite numerous efforts, &#x3b1;5&#x3b2;1-targeting therapeutics have been unsuccessful due to poor efficacy and off-target effects. A contributing factor is our limited understanding of how integrin conformation influences interactions with therapeutics. Using cell-based functional assays, patient derived xenografts, biophysics, and electron microscopy, we shed light on these relationships by characterizing two anti-&#x3b1;5&#x3b2;1 antibodies, BIIG2 and MINT1526A. We show that both antibodies bind &#x3b1;5&#x3b2;1 with nanomolar affinity, reduce angiogenesis in vitro, and bind overlapping epitopes that block fibronectin binding. However, using cryoEM, we reveal that while BIIG2 binding doesn't alter the conformational states, MINT1526A restricts &#x3b1;5&#x3b2;1's range of flexibility. These insights can guide which aspects to prioritize and improve the design of future integrin-targeted therapeutics.

Journal Article

Correlation of extracellular vesicle Alu RNA with brain aging and neuronal injury: a potential biomarker for brain aging.

BACKGROUND: Extracellular vesicles (EVs) are promising biomarkers for neurodegeneration. Alu elements are retrotransposons increasingly expressed with age and may be involved in aging-related diseases. OBJECTIVE: To determine the potential of Alu RNA in plasma-derived EVs as a biomarker for brain aging and neuronal injury. METHODS: EVs were isolated from plasma samples across different age groups. EV Alu RNA levels were measured and their associations with biomarkers of brain aging, including plasma neurofilament light chain (NfL), plasma amyloid-beta (A&#x3b2;42 and A&#x3b2;40), and plasma phosphorylated tau (p-Tau181), were analyzed. RESULTS: EV Alu RNA levels were increased significantly with age and were strongly correlated with plasma NfL, suggesting a strong association between EV Alu RNA and neuronal injury. Significant correlations were also found between EV Alu RNA and plasma amyloid-beta levels, while no significant association was observed with tau pathology. CONCLUSIONS: EV Alu RNA levels are elevated with age and associated with neuronal injury, highlighting their potential as a novel, non-invasive biomarker for brain aging and neurodegeneration.

Humans

The causal relationship between steroid hormones and risk of stroke: evidence from a two-sample Mendelian randomization study.

It is unclear how steroid hormones contribute to stroke, and conducting randomized controlled trials to obtain related evidence is challenging. Therefore, Mendelian randomization (MR) technique was employed in this study to examine this association. Through genome-wide association meta-analysis, the genetic variants of steroid hormones, including testosterone/17&#x3b2;-estradiol (T/E2) ratio, aldosterone, androstenedione, progesterone, and hydroxyprogesterone, were acquired as instrumental variables. Analysis was done on the impact of these steroid hormones on the risk of stroke subtypes. The T/E2 ratio was associated to an elevated risk of small vessel stroke (SVS) according to the inverse variance weighted approach which was the main MR analytic technique (OR, 1.23, 95% CI: 1.05-1.44, p&#x2009;=&#x2009;0.009). These findings were solid since no heterogeneity nor horizontal pleiotropy were found. The causal association between T/E2 and SVS was also confirmed in the replication study (p&#x2009;=&#x2009;0.009). Nevertheless, there was no proof that other steroid hormones increased the risk of stroke. According to this study, T/E2 ratio and SVS are causally related. However, strong evidence for the impact of other steroid hormones on stroke subtypes is still lacking. These findings may be beneficial for developing stroke prevention strategies from steroid hormones levels.

Mendelian Randomization Analysis

Effect of transcutaneous vagus nerve stimulation in hemodialysis patients: A randomized controlled trial.

INTRODUCTION: Transcutaneous auricular vagus nerve stimulation (tVNS) has shown potential in neurological, autoimmune, and cardiovascular disorders, but its effects on HD patients remain unclear. This study aimed to evaluate the efficacy and safety of tVNS in HD patients. METHODS: We conducted a randomized controlled clinical trial on patients receiving HD &#x2265;6&#x2009;months. The tVNS group received stimulation for 1&#x2009;h during the first 2&#x2009;h of HD sessions, three times weekly for 8&#x2009;weeks, while the control group received standard care. The primary outcomes were dialysis efficiency (Single-pool Kt/V, Sp Kt/V) and dialysis-related symptoms (Dialysis Symptom Index, DSI), assessed every 4&#x2009;weeks. Secondary outcomes included pain and fatigue scores, physical performance, Hemodialysis Comfort Scale, hemoglobin levels, Mini-Mental State Examination, and anxiety and depression scores, measured at baseline and 8&#x2009;weeks after intervention. RESULTS: A total of 63 patients were enrolled in the study, with 32 patients assigned to the tVNS group and 31 patients to the control group. At 8&#x2009;weeks, the tVNS group showed significant improvements in Sp Kt/V (1.31&#x2009;&#xb1;&#x2009;0.11 vs. 1.25&#x2009;&#xb1;&#x2009;0.10, p&#x2009;=&#x2009;0.02), and DSI (12.09&#x2009;&#xb1;&#x2009;5.84 vs. 16.26&#x2009;&#xb1;&#x2009;5.27, p&#x2009;=&#x2009;0.004), as well as reductions in pain and fatigue, and increases in physical function, comfort, and hemoglobin. However, there were no statistically significant changes observed in cognitive function, anxiety, or depression. CONCLUSIONS: tVNS could improve dialysis efficiency, symptoms, and physical function in HD patients, indicating it may have a role as a complementary therapy.

Humans

NovoBoard: A Comprehensive Framework for Evaluating the False Discovery Rate and Accuracy of De Novo Peptide Sequencing.

De novo peptide sequencing is one of the most fundamental research areas in mass spectrometry-based proteomics. Many methods have often been evaluated using a couple of simple metrics that do not fully reflect their overall performance. Moreover, there has not been an established method to estimate the false discovery rate (FDR) of de novo peptide-spectrum matches. Here we propose NovoBoard, a comprehensive framework to evaluate the performance of de novo peptide-sequencing methods. The framework consists of diverse benchmark datasets (including tryptic, nontryptic, immunopeptidomics, and different species) and a standard set of accuracy metrics to evaluate the fragment ions, amino acids, and peptides of the de novo results. More importantly, a new approach is designed to evaluate de novo peptide-sequencing methods on target-decoy spectra and to estimate and validate their FDRs. Our FDR estimation provides valuable information to assess the reliability of new peptides identified by de novo sequencing tools, especially when no ground-truth information is available to evaluate their accuracy. The FDR estimation can also be used to evaluate the capability of de novo peptide sequencing tools to distinguish between de novo peptide-spectrum matches and random matches. Our results thoroughly reveal the strengths and weaknesses of different de novo peptide-sequencing methods and how their performances depend on specific applications and the types of data.

Peptides

Genome-wide screening and functional validation of methylation barriers near promoters.

CpG islands near promoters are normally unmethylated despite being surrounded by densely methylated regions. Aberrant hypermethylation of these CpG islands has been associated with the development of various human diseases. Although local genetic elements have been speculated to play a role in protecting promoters from methylation, only a limited number of methylation barriers have been identified. In this study, we conducted an integrated computational and experimental investigation of colorectal cancer methylomes. Our study revealed 610 genes with disrupted methylation barriers. Genomic sequences of these barriers shared a common 41-bp sequence motif (MB-41) that displayed homology to the chicken HS4 methylation barrier. Using the CDKN2A (P16) tumor suppressor gene promoter, we validated the protective function of MB-41 and showed that loss of such protection led to aberrant hypermethylation. Our findings highlight a novel sequence signature of cis-acting methylation barriers in the human genome that safeguard promoters from silencing.

Animals

H4S47 O-GlcNAcylation regulates the activation of mammalian replication origins.

The transmission and maintenance of genetic information in eukaryotic cells relies on the faithful duplication of the entire genome. In each round of division, excessive replication origins are licensed, with only a fraction activated to give rise to bi-directional replication forks in the context of chromatin. However, it remains elusive how eukaryotic replication origins are selectively activated. Here we demonstrate that O-GlcNAc transferase (OGT) enhances replication initiation by catalyzing H4S47 O-GlcNAcylation. Mutation of H4S47 impairs DBF4-dependent protein kinase (DDK) recruitment on chromatin, causing reduced phosphorylation of the replicative helicase mini-chromosome maintenance (MCM) complex and compromised DNA unwinding. Our short nascent-strand sequencing results further confirm the importance of H4S47 O-GlcNAcylation in origin activation. We propose that H4S47 O-GlcNAcylation directs origin activation through facilitating MCM phosphorylation, and this may shed light on the control of replication efficiency by chromatin environment.

Animals