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Biology subjects

Bui, D.

Publications and source records attributed to Bui, D..

15 recordsLinked to original sources

Biologically Informed Multi-Omics Integration Reveals Clinically Meaningful Patient Representations in Acute Myeloid Leukemia

Integrating heterogeneous molecular and clinical data into unified, clinically meaningful patient representations remains a major challenge in precision medicine. Here, we present SurvMOCA-GNN, a biologically informed multi-omics integration framework that explicitly incorporates biological network structure, cross-omics regulatory relationships, and patient-specific clinical information to generate unified patient representations. Using gene expression, microRNA expression, and clinical data from the TCGA-LAML cohort, SurvMOCA-GNN revealed patient representations that identified prognostically distinct patient groups and further stratified patients within established European LeukemiaNet 2022 risk categories. Systematic ablation analyses demonstrated that incorporation of graph-based modeling, cross-omics attention, adaptive clinical integration, and biological prior knowledge progressively improved integration quality, resulting in more structured patient representations and stronger prognostic stratification. Compared with existing multi-omics integration approaches, SurvMOCA-GNN consistently produced more biologically coherent patient representations with improved survival discrimination. Evaluation in an independent AML cohort, together with transfer learning analyses, further demonstrated the robustness and transferability of the integrated representations across heterogeneous patient populations. Together, these findings demonstrate that biologically informed multi-omics integration reveals clinically meaningful patient representations and provides a general framework for integrating heterogeneous molecular and clinical data to improve patient stratification in AML and potentially other diseases. The SurvMOCA-GNN framework is freely available at https://github.com/tjgu/SurvMOCA-GNN.git.

bioinformatics↗

Disease Stage- and Risk-Associated RNA Editing Signatures in Acute Myeloid Leukemia and Their Utility for Peripheral Blood-Based Assessment

RNA editing is a widespread post-transcriptional regulatory mechanism, but its role in acute myeloid leukemia (AML) remains incompletely understood. We analyzed RNA editing in 59 paired diagnosis-relapse AML samples and eight age-matched healthy controls using a stringent discovery pipeline and beta-binomial regression framework accounting for overdispersion and repeated measurements. A total of 166,323 high-confidence RNA editing sites mapping to 5,917 genes were identified. Of tested sites, 1.2%-3.6% varied significantly by disease stage or ELN-2022 risk group. Disease stage-specific editing signatures distinguished healthy controls, diagnosis, and relapse samples, with relapse-associated signals validated in an independent AML cohort. ELN-2022 risk-specific editing signatures showed substantial overlap between intermediate- and adverse-risk groups. Cross-cohort analyses identified four bone marrow (BM) editing sites in TMEM165, COQ4, TIMM17A, and PLXDC2 reproducibly associated with relapse and one peripheral blood (PB) editing site in ABHD18 elevated in higher-risk ELN-2022 groups. Most editing sites were shared between BM and PB; only 2.1%-2.3% exhibited tissue-specific differences. Higher global editing levels were correlated with leukemic state, white blood cell count, and selected clinical features. These findings identify reproducible RNA editing signatures linked to AML disease stage and risk and support the use of RNA editing biomarkers for PB disease assessment.

bioinformatics↗

Single-cell RNA editing defines clinically relevant cellular states in chronic myelomonocytic leukemia

BackgroundChronic myelomonocytic leukemia (CMML) is a clinically heterogeneous myeloid malignancy with limited therapeutic options and suboptimal risk stratification. Although single-cell RNA sequencing has refined disease classification through gene expression profiling, post-transcriptional mechanisms--particularly adenosine-to-inosine (A-to-I) RNA editing--remain unexplored at single-cell resolution. We hypothesized that cell-specific RNA editing programs contribute to CMML heterogeneity and define distinct, clinically actionable cellular states in CMML. MethodsWe developed a single-cell-aware computational framework for high-confidence identification and quantification of RNA editing events. Candidate sites were detected at pseudo-bulk depth using stringent filters and subsequently quantified at single-cell resolution. The pipeline incorporated dual alignment, barcode correction, artifact removal, and exclusion of genomic variants to ensure specificity. We applied this framework to discovery and independent validation CMML cohorts. Editing-defined cellular states were identified by unsupervised clustering of single-cell editing profiles and evaluated for associations with clinical stage, TET2 status, survival, and response to hypomethylating agent (HMA) therapy. Regulatory mechanisms were assessed by analyzing ADAR1/ADAR2 expression and relationships between editing levels and target gene expression. ResultsWe identified 3,326 high-confidence A-to-I RNA editing sites and delineated reproducible editing-defined cellular states. A granulocyte-monocyte progenitor-like editing state (edClu1_sub0) aligned with an inflammatory, monocytic-biased transcriptional program and was significantly associated with adverse survival, advanced-stage disease and TET2-mutant CMML, supporting it as a high-risk biomarker-defined subpopulation. In contrast, states such as edClu3 and edClu6 were enriched in earlier-stage, TET2-wild-type CMML and correlated with improved outcomes. Editing-defined states demonstrated systematic remodeling following HMA therapy, indicating treatment-responsive post-transcriptional programs. The high-risk state exhibited elevated ADAR1 and reduced ADAR2 expression, suggesting enzyme-specific regulatory imbalance as a potential therapeutic vulnerability. Integrative analyses further nominated immune-related genes--including LAPTM5, CTSS, and CD83--as CMML-specific oncogenic RNA editing targets, with coordinated increases in editing and expression within the aggressive state. ConclusionsRNA editing represents a clinically informative and mechanistically relevant layer that refines CMML stratification at single-cell resolution, independent of gene expression. These findings provide a framework for integrating post-transcriptional regulation into precision oncology and highlight RNA editing signatures as biomarkers for risk assessment, treatment monitoring, and therapeutic targeting in hematologic malignancies.

cancer biology↗

Multiscale RNA editing analysis reveals cell type specific regulatory programs across disease states in acute myeloid leukemia

BackgroundAcute myeloid leukemia (AML) is characterized by marked cellular heterogeneity and immune dysregulation. Adenosine-to-inosine (A-to-I) RNA editing, primarily catalyzed by ADAR and ADARB1, represents an important post-transcriptional regulatory mechanism, yet its condition- and cell type-specific landscape in AML remains poorly defined, particularly at single-cell resolution. MethodsWe analyzed publicly available single-cell RNA sequencing data from healthy donors (HL), newly diagnosed AML (ND), remission (RM), and persistent disease (PO), integrating single-cell and pseudo-bulk analyses in a multiscale framework. RNA editing sites were identified using a stringent discovery pipeline and quantified at both pseudo-bulk and cell type-resolved levels. Differential RNA editing was assessed using regression-based read-count models, primarily beta-binomial regression with subject-specific random effects when applicable. Pairwise contrasts between clinical conditions were evaluated using delta-method inference, with statistical significance defined by false discovery rate and a minimum effect-size threshold. Selected editing sites were examined in independent human AML cohorts for validation and clinical association. ResultsWe identified 2,875 recurrent A-to-I RNA editing sites enriched in intronic and 3' untranslated regions and linked to immune and inflammatory pathways. At the pseudo-bulk level, 150 sites were differentially edited across clinical states, and global RNA editing varied by condition, showing an overall negative association with ADAR and ADARB1 expression with context-dependent exceptions. Cell type-resolved analyses identified 148 differentially edited sites with strong lineage specificity. In ND, leukemia-associated cell states consistently exhibited lower editing than lineage-matched healthy counterparts. T cells consistently harbored differential editing signals across all condition contrasts, while progenitor-like cells showed the strongest RM-versus-ND differences despite minimal changes in global editing. Notable editing events were observed in GBP4, SPN, TNFSF10, EMB, and FKBP5. Several candidate sites were validated in independent AML cohorts and were associated with clinical features. ConclusionsThis multiscale analysis reveals that RNA editing in AML is condition- and cell type-specific and is not fully captured by bulk transcriptomic measures. Site-specific, lineage-restricted RNA editing represents a distinct regulatory layer that reflects disease state and cellular context, highlighting its potential relevance for understanding AML biology and informing future biomarker development.

genomics↗

Discovery of miRNA:RNA Biomarkers for Risk Stratification in Acute Myeloid Leukemia with Multi-Cohort Validation

Acute myeloid leukemia (AML) is a clinically aggressive and molecularly heterogeneous malignancy. Current prognostic standards, such as the European LeukemiaNet (ELN) classification, do not fully capture its regulatory complexity. We developed a two-step, PCA-based survival workflow that independently and jointly models gene and miRNA expression to identify biomarkers for patient risk stratification, followed by support vector machine validation across multiple AML cohorts. This strategy enabled rigorous cross-validation while capturing genome-wide regulatory variation. This approach yielded a 19-gene panel--including known oncogenes (e.g., HMGA2, TAL1) and novel candidates (e.g., MLEC, APOE)--that showed robust prognostic performance with validation AUCs>0.879. Parallel analyses identified a 16-miRNA panel enriched for tumor suppressors (e.g., miR-7b-3p, miR-26a-5p) and novel markers (e.g., miR-3613-5p, miR-942-5p), achieving validation AUCs up to 0.916. Integrating experimentally supported miRNA:target interactions revealed 10 coherent regulatory pairs, most showing inverse correlations consistent with miRNA-mediated regulation. Incorporating these regulatory relationships improved prognostic performance compared with single-omic models. Finally, we derived a Cox regression-based molecular risk score that robustly stratified patients and outperformed ELN-2022 risk classification across cohorts. Overall, this framework yields biologically grounded, compact, and reproducible biomarkers with strong prognostic power and provides a generalizable strategy for integrative regulatory modeling in AML.

bioinformatics↗

LIPL-1 and LIPL-2 are TCER-1-regulated Lysosomal Lipases with Distinct Roles in Immunity and Fertility

Reproduction and immunity are fundamental, energy intensive processes that often compete for resources, leading to trade-offs observed across diverse species. Lipid metabolism plays a crucial role in integrating these processes, particularly during stressful conditions such as pathogenic infections. Yet the molecular mechanisms governing this integration remain poorly understood. TCER-1, the C. elegans homolog of mammalian TCERG1, suppresses immunity and promotes fertility, especially upon maternal infection. Here, we show that TCER-1 regulates two conserved lysosomal lipases, lipl-1 and lipl-2, to balance reproduction, immunity and lifespan. Using transcriptomic, lipidomic, and molecular-genetic analyses, we demonstrate that while both lipl-1 and lipl-2 mediate infection-induced lipid remodeling, lipl-1 enhances immunity and catalyzes the accumulation of ceramide species linked to stress response and longevity, whereas, lipl-2 unexpectedly does not. Both lipases contribute towards fertility outcomes, but lipl-2 is especially critical for maintaining embryonic-eggshell integrity during maternal infection and aging. Strikingly, expression of human lysosomal acid lipase (LAL), the ortholog of lipl genes, rescues the immune defects triggered by lipl-l loss and enhances immune resilience. Together, these findings uncover functionally distinct roles for lipl-1 and lipl-2 in modulating lipid species that shape immune fitness, healthspan and reproductive health, and suggest a potentially conserved mechanism by which lipid metabolism links fertility and immunity.

genetics↗

Glycolipid recognition and binding by Siglec-6 hinges on interactions with the cell membrane

Sialic acid-binding immunoglobulin-type lectins (Siglecs) regulate immune response through interactions with sialylated glycans on glycoproteins and glycolipids. Human Siglecs count 14 unique proteins and in all of those the recognition and binding of the sialic acid on the glycan target involves a conserved, or canonical, Arg residue. For a subset of human Siglecs, namely MAG, Siglec-6, and Siglec-11, this Arg appears not to be essential, suggesting that a different binding mechanism may be at play. In this work, we used all-atom molecular dynamics (MD) simulations, binding assays, and mutagenesis to investigate the structural, mechanistic and energetic details of the binding of Siglec-6 to monosialylated gangliosides. Our results show that Siglec-6 relies only partially on its conserved Arg122 for recognition of membrane-bound gangliosides and that it supplements its binding free energy through interactions with the phospholipids in the membrane surrounding the target epitope. We confirmed by mutagenesis assays that the loss of the key residues (Lys 126 and Trp 127) for membrane interaction abrogates binding. These results provide a step-change in our understanding of the diversification of human Siglecs as molecular precision tools to bind specific sialosides by adapting their structure to the biological environment where these are found.

biochemistry↗

The neonatal Fc receptor and DPP4 are human astrovirus receptors

Human astroviruses (HAstV) are major global causes of gastroenteritis, but little is known about host factors required for their cellular entry. Here, we utilized complementary CRISPR-Cas9-based knockout and activation screening approaches and identified neonatal Fc receptor (FcRn) and dipeptidyl-peptidase IV (DPP4) as entry factors for HAstV infection of human intestinal epithelial cells. Disruption of FcRn or DPP4 reduced HAstV infection in permissive cells and, reciprocally, overexpression of these factors in non-permissive cells was sufficient to promote infection. We observed direct binding between FcRn and HAstV virions as well as purified spike protein. Finally, inhibitors for DPP4 and FcRn currently in clinical use prevent HAstV infection in cell lines and primary human enteroids. Thus, our results reveal mechanisms of HAstV entry as well as druggable targets. One-Sentence SummaryTargeting FcRn or DPP4 using available therapies effectively prevents human astrovirus infection in human enteroid cultures.

microbiology↗

RPPA survey of cancer hotspot panel proteins and cell markers in matched tumor-normal human breast and kidney samples reveals a weak correlation between proteins expression and public transcriptome repositories

Despite the tremendous global effort in discovering and cataloguing somatic mutations in cancer-related genes and the impact they exert on human cancers, the effects of these mutations on the levels of protein expression are inadequately addressed. Here, we semi-quantitated the expression of 48 (out of 50) proteins represented by the most widely used cancer hotspot panel, the Ion AmpliSeq Cancer Hotspot Panel v2, and 14 cell markers commonly used as house-keeping proteins, using reverse phase protein array (RPPA) technology in 586 human breast- and 192 kidney matched tumor-normal samples. We further correlated our RPPA data with gene chip data from the Gene Expression Omnibus repository fetched through the TNMplot portal. Nearly half of proteins expression exhibited a negative correlation from their gene expression, while several of the remaining were only moderately correlated. Our data complement the vast information obtained elsewhere by transcriptomic analysis of the respective genes and gene products, potentially assisting in harmonizing proteomic with NGS outputs.

cancer biology↗

Sympathetic Motor Neuron Dysfunction is a Missing Link in Age-Associated Sympathetic Overactivity

Overactivity of the sympathetic nervous system is a hallmark of aging. The cellular mechanisms behind this overactivity remain poorly understood, with most attention paid to likely central nervous system components. In this work, we hypothesized that aging also affects the function of motor neurons in the peripheral sympathetic ganglia. To test this hypothesis, we compared the electrophysiological responses and ion-channel activity of neurons isolated from the superior cervical ganglia of young (12 weeks), middle-aged (64 weeks), and old (115 weeks) mice. These approaches showed that aging does impact the intrinsic properties of sympathetic motor neurons, increasing spontaneous and evoked firing responses. A reduction of M current emerged as a major contributor to age-related hyperexcitability. Thus, it is essential to consider the effect of aging on motor components of the sympathetic reflex as a crucial part of the mechanism involved in sympathetic overactivity.

physiology↗

Viability of HepG2 and MCF-7 Cells is not Correlated with Mitochondrial Bioenergetics

Alterations in metabolism is a hallmark of cancer. It is unclear, however, if oxidative phosphorylation (OXPHOS) is required for tumor cell survival. We investigated the effect of severe hypoxia, site-specific inhibition of respiratory chain (RC) components, and uncouplers on the survival of HepG2 and MCF-7 2D cultured cells. Comparable respiratory complex activities were observed in both cell lines, but HepG2 cells exhibited much higher oxygen consumption rates (OCR) and respiratory capacity than the MCF-7 cells. Significant non-mitochondrial OCR was found in MCF-7 cells that was insensitive to acute combined inhibition of complexes I and III. However, pre-treatment of either cell line with RC inhibitors for 24-72 hours abolished respective complex activities and OCRs completely, and this was associated with a time-dependent decrease in citrate synthase activity, suggesting mitophagy. HepG2 cells viability was mostly unaffected by any pharmacological treatment or severe hypoxia as temporally recorded from high-content automated microscopy. Conversely, MCF-7 cells viability exhibited strong sensitivity to CIV or CV inhibition, severe hypoxia, and uncoupling, but were only moderately affected by CI, CII and CIII inhibition. CII, CIII and CIV-inhibitor mediated MCF-7 cell death were partially abrogated by aspartate. The data show that OXPHOS activity and viability are uncorrelated in these cell lines indicating that a linkage of OXPHOS to cancer cell survival must be cell- and condition-defined.

cancer biology↗

Residual Complex I activity supports glutamate catabolism and mtSLP via canonical Krebs cycle activity during acute anoxia without OXPHOS

Anoxia halts oxidative phosphorylation (OXPHOS) causing an accumulation of reduced compounds in mitochondrial matrix which impedes dehydrogenases. By simultaneously measuring oxygen concentration, NADH autofluorescence, mitochondrial membrane potential and ubiquinone reduction extent in organello in real-time, we show that Complex I utilized endogenous quinones to oxidize NADH under acute anoxia. Untargeted or [U-13C]glutamate-targeted metabolomic analysis of matrix and effluxed metabolites extracted during anoxia in the presence or absence of site-specific inhibitors of the electron transfer system inferred that NAD+ regenerated by Complex I is reduced by the 2-oxoglutarate dehydrogenase complex yielding succinyl-CoA supporting mitochondrial substrate-level phosphorylation (mtSLP), releasing succinate. Yet, targeted metabolomic analysis using [U-13C]malate also revealed concomitant succinate dehydrogenase reversal during anoxia yielding succinate by reducing fumarate, albeit to a small extent. Our results highlight the importance of quinone availability to Complex I oxidizing NADH, thus maintaining glutamate catabolism and mtSLP in the absence of OXPHOS.

biochemistry↗

Multisensory inputs control the regulation of time investment for mating by sexual experience in male Drosophila melanogaster

Males have finite resources to spend on reproduction. Thus, males rely on a time investment strategy to maximize their reproductive success. For example, male Drosophila melanogaster extends their mating duration when surrounded by conditions enriched with rivals. Here we report a novel form of behavioral plasticity whereby male fruit flies exhibit a shortened duration of mating when they are sexually experienced; we refer to this plasticity as shorter-mating-duration (SMD). SMD is a plastic behavior and requires sexually dimorphic taste neurons. We identified several neurons in the male foreleg and midleg that express specific sugar, pheromone and mechanosensory receptors. Using a cost-benefit model and behavioral experiments, we further show that SMD behavior exhibits adaptive behavioral plasticity in male flies. Thus, our study delineates the molecular and cellular basis of the sensory inputs required for SMD; this represents a plastic interval timing behavior that could serve as a model system to study how multisensory inputs converge to modify interval timing behavior for improved adaptation. ONE SENTENCE SUMMARYMale flies use information derived from their previous sexual experiences from multiple sensory inputs to optimize their investment in mating.

neuroscience↗

In vivo selection reveals long non-coding RNAs implicated in colon to liver metastasis

Colorectal cancer (CRC) is the third most common malignancy in both American men and women. Most of the deaths attributed to CRC are a result of metastatic spread to the liver. In this study, colon cancer cells that highly metastasized to liver in vivo were compared to less metastatic parental cells to investigate the role for long non-coding RNAs (lncRNAs) in CRC metastasis. The highly metastatic daughter cells (LS-3B) were found to be 63-fold more metastatic than the parental cell line (LS-PAR) in vivo. A lncRNA microarray comparing LS-PAR and LS-3B cells revealed that 104 lncRNAs had fold changes > 2.0 and an FDR < 0.05. Real time PCR mediated validation revealed many lncRNAs exhibited high fold changes such as a 60-fold increase in LOC101448202, a 20-fold increase in MRPL23-AS1 and 50-fold decreases in GNAS-AS1 and LOC101928131. In vivo metastasis differences could be recapitulated in vitro as LS-3B cells closed wounds faster than their parental LS-PAR cells. However, intestinal epithelial cancer cells with robust downregulation of MRPL23-AS1, C1QTNF1-AS1, GNAS-AS1, LINCR-0002 and LOC101448202 failed to display differences in comparison to controls in in vitro migration assays. Three of the five lncRNAs with microarray probes for currently available GEO-datasets were significantly altered in liver CRC-associated tumor biopsies as compared to the primary tumor of non-metastatic CRC. Further studies on the lncRNAs identified will better define their roles in metastasis and how they might be useful if targeted therapeutically.

cancer biology↗

Antibiotic-induced accumulation of lipid II sensitizes bacteria to antimicrobial fatty acids

Antibiotic tolerance and antibiotic resistance are the two major obstacles to the efficient and reliable treatment of bacterial infections. Identifying antibiotic adjuvants that sensitize resistant and tolerant bacteria to antibiotic killing may lead to the development of superior treatments with improved outcomes. Vancomycin, a lipid II inhibitor, is of major clinical importance for the treatment of Gram-positive bacterial infections. Here we show that unsaturated fatty acids (UFAs) and vancomycin act synergistically to rapidly kill S. aureus, including vancomycin tolerant and resistant populations. Our results suggest that antibiotic-mediated accumulation of lipid II at the septum facilitates membrane invasion by antimicrobial UFAs. UFA-vancomycin dual treatment generates large fluid patches of flexible lipids in the membrane leading to protein delocalization, aberrant septal formation, and loss of membrane integrity. This mechanism of synergy may be exploited for the development of new antibiotic therapies that target lipid II to combat both antibiotic tolerance and resistance.

microbiology↗