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Geng, B.

Publications and source records attributed to Geng, B..

9 recordsLinked to original sources

Machine learning classifies subcellular Golgi morphology from imaging flow cytometry during inflammatory activation: an exploratory study

Inflammatory activation remodels the Golgi apparatus to meet increased secretory demand, yet whether these structural changes carry computationally accessible information about immune cell state has not been explored. Here we show that machine learning applied to imaging flow cytometry images of the Golgi can distinguish lipopolysaccharide (LPS) treated from control cells. We trained models on Golgi images from human THP-1 monocytes before and 16 h after LPS stimulation in vitro, and from circulating myeloid cells of mice 24 h after intratracheal LPS or saline in vivo. In each dataset, the best-performing model was a deep learning model trained directly on images rather than a classifier using predefined morphometric features. Cross-domain performance varied with the model, transfer direction and use of labelled target data: several deep learning models trained on mouse images classified THP-1 cells above chance without changing model parameters. Grad-CAM highlighted regions within or adjacent to the GM130 fluorescence pattern. These findings indicate that GM130 images carry information associated with LPS treatment that supports classification within and across the two datasets. To our knowledge, this is the first application of supervised deep learning to imaging flow cytometry images of a subcellular organelle for inflammatory phenotyping, establishing organelle level image analysis as a potential complement to molecular assays for immune cell classification.

bioinformatics↗

SIGMA: SIgnaling via Golgi Morphology Analysis for pathway-state classification

Organelle morphology is increasingly recognized as a computationally accessible readout of molecular state, yet whether subcellular architecture can identify which signaling pathway is active, not merely whether a cell is perturbed, remains untested. Here we introduce SIGMA (SIgnaling via Golgi Morphology Analysis), a framework that reframes pathway identification as a morphological classification problem centered on the Golgi apparatus. SIGMA integrates imaging flow cytometry for population-scale Golgi profiling, teacher-student knowledge distillation to transfer fine morphological cues from limited high-resolution images to an efficient lower-resolution classifier, and mechanistic generalization testing with chemically distinct activators. Applied to MRC-5 fibroblasts across six conditions spanning four signaling cascades plus controls, SIGMA achieved 90.02% cell-level accuracy and correctly assigned five of seven structurally unrelated external compounds to their expected pathway class. These results establish Golgi morphology as a multiplexed, machine-readable fingerprint of signaling state.

molecular biology↗

No more than three PlpE non-overlapping epitopes trigger significant antibody production in individuals vaccinated with the Pasteurella multocida epitope-chimeric proteins

Current vaccine research still confronts multiple challenges, and epitope-focused vaccine design serves as an effective technical approach to address these issues. Antigens harbor multiple epitopes; however, the number of epitopes capable of triggering significant antibody responses in vaccinated individuals remains undefined. This study aimed to determine the number of non-overlapping epitopes--designated "effective epitopes" hereafter--that trigger significant antibody production in vaccinated individuals when presented in distinct PlpE epitope-chimeric proteins. Herein, chimeric proteins incorporating varying numbers of PlpE non-overlapping B-cell epitopes were generated. By analyzing serum antibody responses in vaccinated individuals, the number characteristic of PlpE effective epitopes was elucidated. The total number of PlpE effective epitopes in vaccinated individuals was 2.6 (95%CI: 1.909-3.201) for full-length PlpE, and 1.2 (95%CI: 0.5426-1.857), 0.9 (95%CI: 0-1.820), and 0.2 (95%CI: 0-0.5016) for the PlpE chimeric proteins (PlpE-VP60P, PlpE-BcfA, PlpE-PtfA), respectively. With an increase in the number of PlpE non-overlapping epitopes incorporated into the chimeric proteins, the number of PlpE effective epitopes exhibited a trend of initial increase followed by a decrease. Ultimately, the average total number of effective epitopes across all PlpE chimeric proteins did not exceed 3, with the highest number 2.1 (95%CI: 1.572-2.628). In conclusion, the number of PlpE non-overlapping epitopes on an antigen, that trigger significant antibody responses in each vaccinated individual, is very limited. IMPORTANCEEpitopes underpin the antigenicity of protein antigens. Although the concept of antigenic epitopes has been proposed over 50 years, our understanding on epitopes remains incomplete. Multiple antigenic epitopes can be identified on a single antigen, while the number of these epitopes that function in vaccinated individuals remains unclear--a gap hindering the rational design of vaccines. In previous studies, we identified 6 non-overlapping epitopes of Pasteurella multocida PlpE. Herein, we found that the total number of non-overlapping epitopes--capable of significantly triggering antibody production--that are present in PlpE chimeric proteins does not exceed 3 per vaccinated individual. This finding offers important insights for rational vaccine design: given the highly limited number of non-overlapping epitopes that function in vaccinated individuals, only a limited number of epitopes can be grafted onto scaffold proteins. Epitope-focused vaccine design must therefore account for competitive interactions between epitopes on the new antigen.

immunology↗

Comparative single-cell lineage bias in human and murine hematopoietic stem cells

The commitment of hematopoietic stem cells (HSC) to myeloid, erythroid, and lymphoid lineages is influenced by microenvironmental cues, and governed by cell-intrinsic and epigenetic characteristics that are unique to the HSC population. To investigate the nature of lineage commitment bias in human HSC, mitochondrial single cell (sc) ATAC-Sequencing (mt-scATAC-Seq) was used to identify somatic mutations in mitochondrial DNA to act as natural genetic barcodes for tracking the ex vivo differentiation potential of HSC to mature cells. Clonal lineages of human CD34+ cells and their mature progeny were normally distributed across the hematopoietic lineage tree without evidence of significant skewing. To investigate commitment bias in vivo, mice were transplanted with limited numbers of long-term HSC (LT-HSC). Variation in the ratio of myeloid and lymphoid cells between donors, although suggestive of a skewed output, was not altered by increasing numbers of LT-HSC. These data suggest that the variation in myeloid and lymphoid engraftment is a stochastic process influenced by the irradiated recipient niche and not a cell-intrinsic lineage bias of LT-HSC.

genomics↗

Omicron Spike Protein Is Vulnerable to Reduction

SARS-CoV-2 virus spike (S) protein is an envelope protein responsible for binding to the ACE2 receptor, driving subsequent entry into host cells. The existence of multiple disulfide bonds in the S protein makes it potentially susceptible to reductive cleavage. Using a tri-part split luciferase-based binding assay, we evaluated the impacts of chemical reduction on S proteins from different virus variants and found that those from the Omicron family are highly vulnerable to reduction. Through manipulation of different Omicron mutations, we found that alterations in the receptor binding module (RBM) are the major determinants of this vulnerability. Specifically we discovered that Omicron mutations facilitate the cleavage of C480-C488 and C379-C432 disulfides, which consequently impairs binding activity and protein stability. The vulnerability of Omicron S proteins suggests a mechanism that can be harnessed to treat specific SARS-CoV-2 strains.

biochemistry↗

MMD scaffolds ACSL4 and MBOAT7 to promote polyunsaturated phospholipid synthesis and susceptibility to ferroptosis

Ferroptosis is a form of regulated cell death with roles in degenerative diseases and cancer. Ferroptosis is driven by excessive iron-dependent peroxidation of membrane phospholipids, especially those containing the polyunsaturated fatty acid arachidonic acid. Here, we reveal that an understudied Golgi membrane scaffold protein, MMD, promotes susceptibility to ferroptosis in ovarian and renal carcinoma cells. Upregulation of MMD correlates with sensitization to ferroptosis upon monocyte-to-macrophage differentiation. Mechanistically, MMD interacts with ACSL4 and MBOAT7, two enzymes that catalyze consecutive reactions in the biosynthesis of phosphatidylinositol (PI) containing arachidonic acid. MMD increases cellular levels of arachidonoyl-phospholipids and heightens susceptibility to ferroptosis in an ACSL4- and MBOAT7-dependent manner. We propose that MMD potentiates the synthesis of arachidonoyl-PI by bridging ACSL4 with MBOAT7. This molecular mechanism not only clarifies the biochemical underpinnings of ferroptosis susceptibility, with potential therapeutic implications, but also contributes to our understanding of the regulation of cellular lipid metabolism. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/506096v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@1e5c469org.highwire.dtl.DTLVardef@1c1ec52org.highwire.dtl.DTLVardef@820cceorg.highwire.dtl.DTLVardef@16ca7e_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

Immunologically distinct responses occur in the CNS of COVID-19 patients

One third of COVID-19 patients develop significant neurological symptoms, yet SARS-CoV-2 is rarely detected in central nervous system (CNS) tissue, suggesting a potential role for parainfectious processes, including neuroimmune responses. We therefore examined immune parameters in cerebrospinal fluid (CSF) and blood samples from a cohort of patients with COVID-19 and significant neurological complications. We found divergent immunological responses in the CNS compartment, including increased levels of IL-12 and IL-12-associated innate and adaptive immune cell activation. Moreover, we found increased proportions of B cells in the CSF relative to the periphery and evidence of clonal expansion of CSF B cells, suggesting a divergent intrathecal humoral response to SARS-CoV-2. Indeed, all COVID-19 cases examined had anti-SARS-CoV-2 IgG antibodies in the CSF whose target epitopes diverged from serum antibodies. We directly examined whether CSF resident antibodies target self-antigens and found a significant burden of CNS autoimmunity, with the CSF from most patients recognizing neural self-antigens. Finally, we produced a panel of monoclonal antibodies from patients CSF and show that these target both anti-viral and anti-neural antigens--including one mAb specific for the spike protein that also recognizes neural tissue. This exploratory immune survey reveals evidence of a compartmentalized and self-reactive immune response in the CNS meriting a more systematic evaluation of neurologically impaired COVID-19 patients. One Sentence SummaryA subset of COVID-19 patients with neurologic impairment show cerebrospinal fluid-specific immune alterations that point to both neuroinvasion and anti-neural autoimmunity as potential causes of impairment.

immunology↗

DAZL is a master translational regulator of murine spermatogenesis

Expression of DAZ-like (DAZL) is a hallmark of vertebrate germ cells and essential for embryonic germ cell development and differentiation, yet gametogenic function of DAZL has not been fully characterized with most of its in vivo direct targets unknown. We showed that postnatal stage-specific deletion of Dazl in mouse germ cells did not affect female fertility, but caused complete male sterility with gradual loss of spermatogonial stem cells (SSCs), meiotic arrest and spermatid arrest respectively. Using the genome-wide HITS-CLIP and mass spectrometry approach, we found that DAZL bound to a large number of testicular mRNA transcripts (at least 3008) at 3' UnTranslated Region (3' UTR) and interacted with translation proteins including PABP. In the absence of DAZL, polysome-associated target transcripts, but not their total transcripts were significantly decreased, resulting in drastic reduction of an array of spermatogenic proteins and thus developmental arrest. Thus, DAZL is a master translational regulator essential for spermatogenesis.

developmental biology↗

DrugPattern: a web-based tool for drug set enrichment analysis

Set enrichment analysis based methods (e.g. gene set enrichment analysis) have provided great helps in mining patterns in biomedical datasets, however, tools for inferring regular patterns in drug-related datasets are still limited. For the above purpose, here we developed a web-based tool, DrugPattern. DrugPattern first collected and curated 7019 drug sets, including indications, adverse reaction, targets, pathways etc. For a list of interested drugs, DrugPattern then evaluates the significance of the enrichment of these drugs in each of the 7019 drug sets. To validate DrugPattern, we applied it to predict the potential protective roles of oxidized low-density lipoprotein (oxLDL), a widely accepted deleterious factor for the body. We predicted that oxLDL has beneficial effects on some diseases, most of which were supported by literature except type 2 diabetes (T2D), in which oxLDL was previously believed to be a risk factor. Animal experiments further validated that oxLDL indeed has beneficial effects on T2D. These data confirmed the prediction accuracy of our approach and revealed unexpected protective roles for oxLDL in various diseases including T2D. This study provides a tool to infer regular patterns in biomedical datasets based on drug set enrichment analysis.

bioinformatics↗