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At least 19 recordsLinked to original sources

Functional screening and single-cell cultivation of marine CO2-fixing bacteria via flow-mode Raman-activated cell sorting.

Most marine CO2-fixing microorganisms remain uncultivated due to strong culture bias and low throughput of conventional approaches, which fail to link in situ function with isolated strains and render slow-growing or low-abundance taxa virtually inaccessible. This study presents an integrated single-cell workflow that incorporates 13C-NaHCO3 labeling, high-throughput flow-mode Raman-activated cell sorting (RACS) and microwell cultivation for the isolation of active CO2-fixing bacteria from the Yellow Sea. Function-guided sorting was achieved by monitoring the 13C-induced Raman shifts of carotenoids (ν1 band: ∼1507 to ∼ 1503.78 cm-1 at 24 h). Genomic and physiological analyses identified Paraburkholderia aromaticivorans FR-4 as a novel facultative chemoautotrophic nitrite-oxidizing bacterium (NOB). Its genome encodes complete nitrite oxidation and Calvin cycle pathways, together with key carbon acquisition genes (carbonic anhydrase, bicarbonate transporter). FR-4 grows autotrophically using NO2- as the electron donor and CO2/HCO3- as the carbon source, confirming its ability to couple nitrite oxidation with carbon fixation, while retaining metabolic flexibility for heterotrophic growth. By directly linking in situ carbon-fixing activity, genotype, and phenotype, this workflow provides a targeted strategy for exploring elusive marine CO2-fixing bacteria and overcomes critical limitations of conventional cultivation.

Carbon-fixing

Automatic cell identification and enrichment in lung cancer. II. Acridine orange for cell sorting of sputum.

Fluorescence spectra were obtained from cells from sputum and pleural effusions stained with different fluorescent dyes and fixed by alternate methods. The spectra were referenced to a standard allowing for fluorescence comparisons of unstained and stained cells under various conditions. The metachromasia of acridine orange-stained cells offers nuclear/cytoplasmic differentiation in a single stain; mithramycin and propidium iodide do not. Unstained cells have an appreciable amount of green (546 nm) fluorescence, as does Carbowax in Saccomanno's preservative. Cytoplasm stained with acidine orange also has appreciable green fluorescence. Consequently, cells with much cytoplasm have high total fluorescence. Cytoplasmic fluorescence is negligible with mithramycin or propidium iodide. The metachromasia of acridine orange-stained cells is altered by alcohol and Carbowax levels in fixatives, keeping other factors constant.

Acridine Orange

Penalised regression improves imputation of cell-type specific expression using RNA-seq data from mixed cell populations compared to domain-specific methods.

Gene expression studies often use bulk RNA sequencing of mixed cell populations because single cell or sorted cell sequencing may be prohibitively expensive. However, mixed cell studies may miss expression patterns that are restricted to specific cell populations. Computational deconvolution can be used to estimate cell fractions from bulk expression data and infer average cell-type expression in a set of samples (e.g., cases or controls), but imputing sample-level cell-type expression is required for more detailed analyses, such as relating expression to quantitative traits, and is less commonly addressed. Here, we assessed the accuracy of imputing sample-level cell-type expression using a real dataset where mixed peripheral blood mononuclear cells (PBMC) and sorted (CD4, CD8, CD14, CD19) RNA sequencing data were generated from the same subjects (N=158), and pseudobulk datasets synthesised from eQTLgen single cell RNA-seq data. We compared three domain-specific methods, CIBERSORTx, bMIND and debCAM/swCAM, and two cross-domain machine learning methods, multiple response LASSO and ridge, that had not been used for this task before. We also assessed the methods according to their ability to recover differential gene expression (DGE) results. LASSO/ridge showed higher sensitivity but lower specificity for recovering DGE signals seen in observed data compared to deconvolution methods, although LASSO/ridge had higher area under curves than deconvolution methods. Machine learning methods have the potential to outperform domain-specific methods when suitable training data are available.

Humans

Novel and High-Throughput Method of Isolating Single Fetal Cells Using FACS for NIPT.

OBJECTIVE: To evaluate fluorescence activated cell sorting (FACS) as a method of single-cell isolation of rare circulating fetal cells from maternal blood for use in cell-based non-invasive prenatal testing (cbNIPT). METHOD: Blood samples (30 mL) were collected from 75 'low-risk' pregnant women (gestational age 10-15 weeks). Fetal cells were enriched and stained using magnetic activated cell sorting. Following enrichment, single fetal cells were sorted in individual PCR tubes by FACS. After cell lysis, verification of fetal cell origin was performed using short tandem repeat (STR) analysis with the GlobalFiler PCR Amplification kit. RESULTS: An average of 13.7 cells were sorted using FACS. STR analysis identified 8.2 fetal cells on average, representing 60.2% of the sorted cells. The four-step single-cell isolation procedure facilitated an overall enrichment of approximately 16-million-fold. One sample did not render any fetal cell, corresponding to 1.3% of the samples. CONCLUSION: FACS, which is typically used for segregation of large populations of cells, can be used for single-cell isolation of rare fetal cells in an automated setup. This not only helps in making cell isolation faster and high throughput but also provides fetal cells for a more comprehensive genetic analysis of the fetus.

Humans

Translation of scRNA-seq to a clinical blood test for infection diagnostics.

INTRODUCTION: Early and accurate triage of patients with febrile illness is crucial for appropriate treatment. While standard inflammatory biomarkers are often nonspecific, transcriptome analysis of peripheral blood has diagnostic potential. However, bulk gene expression data is often confounded by changes in cell count proportions, a more robust quantification of gene expression in specific single-cell types, such as monocytes, is required to serve as a reliable clinical biomarker. AREAS COVERED: Various methods to obtain single-cell-type gene expression results, including the gold standard of gene expression analysis after cell sorting and single-cell RNA sequencing, which are difficult to implement in the routine settings are discussed. Other method to interrogate gene expression of a single cell-type is needed. Finally, monocyte cell-type specific ratio-based biomarker (RBB, called Direct Leukocyte Single cell-type Transcript Abundance, or DIRECT LS-TA) which can estimate single cell-type (monocyte) specific gene expression without cell sorting is introduced. EXPERT OPINION: Traditional diagnostic test for differentiating infection has several limitations requiring breakthrough including turn-around time and cost. DIRECT LS-TA provides a reliable way to quantify monocyte-specific gene expression that strongly correlates with gold-standard methods. It is more affordable than single-cell RNA sequencing and can be readily implemented in clinical laboratories using widely available quantitative PCR or digital PCR machines.

Humans

Revealing differential expression patterns of piRNA in FACS blood cells of SARS-CoV-2 infected patients.

Non-coding RNA expression has shown to have cell type-specificity. The regulatory characteristics of these molecules are impacted by changes in their expression levels. We performed next-generation sequencing and examined small RNA-seq data obtained from 6 different types of blood cells separated by fluorescence-activated cell sorting of severe COVID-19 patients and healthy control donors. In addition to examining the behavior of piRNA in the blood cells of severe SARS-CoV-2 infected patients, our aim was to present a distinct piRNA differential expression portrait for each separate cell type. We observed that depending on the type of cell, different sorted control cells (erythrocytes, monocytes, lymphocytes, eosinophils, basophils, and neutrophils) have altering piRNA expression patterns. After analyzing the expression of piRNAs in each set of sorted cells from patients with severe COVID-19, we observed 3 significantly elevated piRNAs - piR-33,123, piR-34,765, piR-43,768 and 9 downregulated piRNAs in erythrocytes. In lymphocytes, all 19 piRNAs were upregulated. Monocytes were presented with a larger amount of statistically significant piRNA, 5 upregulated (piR-49039 piR-31623, piR-37213, piR-44721, piR-44720) and 35 downregulated. It has been previously shown that piR-31,623 has been associated with respiratory syncytial virus infection, and taking in account the major role of piRNA in transposon silencing, we presume that the differential expression patterns which we observed could be a signal of indirect antiviral activity or a specific antiviral cell state. Additionally, in lymphocytes, all 19 piRNAs were upregulated.

Humans

Analysis and sorting of living cells according to deoxyribonucleic acid content.

The methods for measuring the deoxyribonucleic acid content of individual mammalian cells and sorting them on the basis of this parameter have until now required fixation or other treatment which renders the cells nonviable. Using a class of bis-benzimidazole dyes, Hoechst 33258 and 33342 and a multiparameter computer-controlled cell sorter, we have been able to stain and separate living cells in the G1, S, and G2+M phases of the cell cycle and to continue their growth in tissue culture with high retention of viability (greater than 90%) and no increase in heteroploidy. The quenching of the fluorescence of the bound dye by 5-bromodeoxyuridine incorporated into cellular deoxyribonucleic acid is being used with the flow system to detect and isolate mutants in deoxyribonucleic acid metabolism spectroscopically.

Benzimidazoles

A Dual-Selection System for Enhanced Efficiency and Fidelity of Circular RNA Overexpression.

Circular RNAs (circRNAs) are essential regulators of cellular processes, but are challenging to study using traditional methods. Overexpression approaches, such as the use of linearized plasmids and viral vectors, often result in high rates of false-positive clones, where cells retain selection markers without expressing the target circRNA. This study addresses this limitation by developing a dual-selection circRNA system designed to enhance the accuracy and reliability of circRNA overexpression. Our system integrates a fluorescent reporter gene upstream of the circRNA expression cassette, under a shared promoter, and a downstream antibiotic resistance marker, allowing for both antibiotic selection and flow cytometric cell-sorting to identify and enrich cells with genuine circRNA expression. We successfully incorporated this system into an inducible lentiviral vector for controlled overexpression in various cell types. The dual-selection circRNA system offers a significant advance for circRNA research and studies of other RNA species where accurate and reliable overexpression is essential.

RNA, Circular

The Role of Polo-Like Kinase 1 (PLK1) O-GlcNAcylation in Mitosis.

Polo-like kinase 1 (PLK1) is a crucial mitotic kinase that is implicated in various aspects of cell cycle. Many post-translational modifications have been identified on PLK1 to regulate its activation, stability, and localization. PLK1 has been shown previously to colocalize with the O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT), and OGT regulates PLK1 stability. In our recent work, we show that PLK1 is O-GlcNAcylated by click chemistry. Using stepped collisional energy/higher energy collision dissociation mass spectrometry, we mapped the PLK1 O-GlcNAc site to be T291. We further utilized fluorescent activated cell sorting and time-lapse microscopy to assess the mitotic defects of PLK1 O-GlcNAc mutants. In vivo studies in mouse xenograft demonstrated that it promoted uterine cancer tumorigenesis. In this chapter, we delineate the methodologies we used in studying PLK1 O-GlcNAcylation, including click chemistry, stepped collisional energy/higher energy collision dissociation mass spectrometry, fluorescent activated cell sorting, time-lapse microscopy, and mouse xenograft assays.

Polo-Like Kinase 1

IDH2 clonal hematopoiesis and IKAROS loss cooperate in a B-ALL subtype after lenalidomide therapy for multiple myeloma.

Lenalidomide, a maintenance treatment in multiple myeloma first-line therapy, increases the risk of secondary malignancies, including B-cell precursor acute lymphoblastic leukemia (B-ALL). We present a comprehensive molecular characterization of 57 patients with lenalidomide-associated B-ALL (LenB-ALL), revealing 3 mutational subgroups: (1) TP53mt (30%); (2) IDH2mt (p.R140Q) (23%); and (3) other, including NRAS/KRASmt. Remarkably, IDH2 R140Q mutations were highly enriched in LenB-ALL compared with those in primary B-ALL (P< .001). Furthermore, IKZF1 intragenic deletions, often subclonal and likely RAG recombinase-mediated, were observed in 54% (7/13) of IDH2mt patients with LenB-ALL. IDH2 mutations were not restricted to the leukemic clone: they persisted during measurable residual disease-negative remission and were identified in lymphoid as well as myeloid cell populations using fluorescence-activated cell sorting and single-cell RNA sequencing. This indicates a preleukemic origin of the IDH2 mutation within the context of clonal hematopoiesis. Transcriptomic and DNA methylation analyses revealed a distinct gene expression profile and a DNA hypermethylation phenotype in IDH2mt LenB-ALL, including IDH2mt-specific as well as lenalidomide-associated features. We propose that lenalidomide promotes the expansion of IDH2-mutated clonal hematopoiesis and, via IKAROS downregulation, induces a maturation arrest at the B-cell precursor stage. Subsequent genetic or epigenetic alterations render leukemogenesis independent of ongoing lenalidomide exposure. All these data define IDH2mt B-ALL as a distinct molecular subtype that is markedly overrepresented after lenalidomide treatment and highlight clonal hematopoiesis as a key contributing factor in the development of LenB-ALL.

Humans

Automatic cell identification and enrichment in lung cancer. I. Light scatter and fluorescence parameters.

Two physical parameters were investigated to automatically recognize cells in sputum from human squamous cell carcinoma of the lung and to separate them for preparation by the Papanicolaou methods, for human interactive identification and for automated high resolution image analysis. The two parameters, 0.5-15.0 degrees forward argon-ion laser light scatter to estimate total cell size and 546 nm Acridine orange fluorescence to approximate total cell DNA content, were measured in a flow-through fluorescence activated cell sorting system. Enrichment for neoplastic cells in three cases of squamous cell carcinoma of the lung averaged 7.8-fold over the original sputum when only green fluorescence was used and 10.5-fold using green fluorescence and forward light scatter. The average enrichment for neoplastic cells was 65.6-fold relative to polymorphonuclear deenrichment.

Carcinoma, Squamous Cell

Single-cell vector copy number analysis of phenotypically defined long-term hematopoietic stem cells for gene therapy safety assessment.

Hematopoietic stem cell (HSC)-based gene therapy has emerged as a transformative approach for the treatment of genetic diseases; however, accurate evaluation of vector copy number (VCN) remains critical for ensuring safety. Conventional bulk VCN assays, including quantitative PCR (qPCR) and droplet digital PCR (ddPCR), do not resolve clonal heterogeneity and cannot identify rare high-VCN cells that may contribute disproportionately to insertional mutagenesis risk. Here, we developed an accessible single-cell VCN profiling method by combining fluorescence-activated cell sorting (FACS) of phenotypically defined long-term HSCs (Lineage- CD34+ CD38- CD90+ CD45RA- cells) with whole-genome amplification followed by conventional qPCR. This approach enabled resolution of VCN distributions at single-cell level using standard laboratory techniques. Notably, single-cell analysis revealed a high VCN tail that bulk VCN analysis could not resolve. Furthermore, in a humanized mouse transplantation model, single-cell VCN profiling demonstrated that overall VCN distributions could be analyzed after engraftment, although inter-donor and inter-mouse variability was observed. Collectively, this method provides a rapid, cost-effective, and phenotypically resolved strategy for assessing VCN heterogeneity in gene-modified HSCs. Single-cell VCN profiling offers complementary insights beyond conventional bulk assays and may enhance preclinical safety evaluation of gene and cell therapy products.

lentiviral vector

FACS-Proteomics strategy toward extracellular vesicles single-phenotype characterization in biological fluids: exploring the role of leukocyte-derived EVs in multiple sclerosis.

BACKGROUND: The isolation and proteomics characterization of extracellular vesicles (EVs) from body fluids is challenging due to their vast heterogeneity. We have recently demonstrated that Fluorescence-activated Cell Sorting (FACS) efficiently isolates the whole EV circulating compartment directly from untouched body fluids enabling a comprehensive EV proteomics analysis. RESULTS: Here, we characterized, for the first time, a single-phenotype EV subset by sorting leukocyte-derived EVs (Leuko EVs) from peripheral blood and tears of healthy volunteers.&#xa0;Using an optimized and patented staining protocol of the whole EV compartment we identified and excluded non-EV particles, debris and damaged EVs. We further isolated, using an anti-CD45 antibody, Leuko EVs (CD45+&#x2009;EVs), reaching a high level of purity (>&#x2009;90%). Purified Leuko EVs were characterized using atomic force microscopy, nanoparticle tracking, and shotgun proteomics analysis revealing a similar coded protein cargo in both biological fluids. Subsequently, the same workflow was applied to tears from Relapsing-Remitting Multiple Sclerosis (RRMS) patients, revealing a Leuko EVs protein cargo enrichment that reflects the neuroinflammatory condition characteristics of RRMS. This enrichment was evidenced by the activation of upstream regulators TGFB1 and NFE2L2, which are associated with inflammatory responses. Additionally, the analysis identified markers indicative of endothelial cell proliferation and the development of enhanced vascular networks, with AGNPT2 and VEGF emerging as activated upstream regulators. These findings indicate the complex interplay between inflammation and angiogenesis in RRMS. CONCLUSIONS: In conclusion, our combined FACS-Proteomics strategy offers a promising approach for biomarker discovery, analysing cell-specific EV phenotypes directly from untouched body fluids, advancing the clinical value of tears EVs and improving the understanding of EV-mediated processes in vivo. Data are available via ProteomeXchange with the identifier PXD049036 and in EV-TRACK knowledgebase with ID: EV240150.

Humans

Genome-wide association studies with experimental validation identify a protective role for B lymphocytes against chronic post-surgical pain.

BACKGROUND: Chronic post-surgical pain (CPSP) significantly impacts patients' recovery and quality of life. Although environmental risk factors are well-established, genetic risk remains less understood. METHODS: A meta-analysis of genome-wide association studies followed by partitioned heritability was performed on 1350 individuals across five surgery types: hysterectomy, mastectomy, abdominal, hernia, and knee. In subsequent animal studies, withdrawal thresholds to evoked mechanical stimulation were measured in Rag1 null mutant and wild-type mice after plantar incision and laparotomy. Cell sorting by flow cytometry tracked recruitment of immune cell types. RESULTS: We discovered 77 genome-wide significant single-nucleotide polymorphism (SNP) hits, distributed among 24 loci and 244 genes. Meta-analysis of all cohorts estimated a SNP-based narrow-sense heritability for CPSP at &#x223c;39%, indicating a substantial genetic contribution. Partitioned heritability analysis across a wide variety of tissues revealed enrichment of heritability in immune system-related genes, particularly those associated with B and T cells. Rag1 null mutant mice lacking both T and B cells exhibited exacerbated and prolonged allodynia up to 42 days after surgery, which was rescued by B-cell transfer. Recruitment patterns of B cells but not T cells differed significantly during the first 7 days after injury in the footpad, lymph nodes, and dorsal root ganglia. CONCLUSIONS: These findings suggest a key protective role for the adaptive immune system in the development of chronic post-surgical pain.

Animals

Plasmodium-infected blood cells analyzed and sorted by flow fluorimetry with the deoxyribonucleic acid binding dye 33258 Hoechst.

Red cells from Plasmodium berghei infected mouse blood can be sorted on the basis of their DNA content with the bisbenzimidazole dye 33258 Hoechst. The optimal conditions for dye uptake have been established and with these conditions uninfected cells are nonfluorescent and can be completely separated from infected cells which exhibit fluorescence in almost direct proportion to the number of parasite nuclei (i.e. DNA) they contain. The number of fluorescent cells detected and their fluorescence intensity is shown to be dependent on the dye concentration and the incubation medium being used. At least a proportion of the infected cells sorted from each fluorescence peak in the cell distribution retain their infectivity in vivo with some, but not all, conditions of labeling. This technique is being used to separate minor cell populations from infected blood for biochemical and immunochemical analyses and to screen human samples for malaria infected cells.

Animals

Automatic cell identification and enrichment in lung cancer. III. Light scatter and two fluorescence parameters.

Two fluorescence parameters and size are used in a flow through system to enrich sputum specimens for cancer cells. Human cells in sputum which are stained with acridine orange show a characteristic distribution of red and green fluorescence from which cancer cells can be localized. The peak enrichment is obtained by selectively sorting cells with the largest values of red and green fluorescence. Cancer cells located in other distribution regions having smaller fluorescence intensities show progressively diminished nuclear and cytoplasmic tinctorial features by Papanicolaou stain, consistent with the decreased intensity of red and green fluorescence.

Carcinoma, Squamous Cell

Uncovering the signaling networks of disseminated glioblastoma cells in vivo with INSIGHT.

Dysregulation of intracellular signaling networks underpins cancer. Yet, resolving signaling networks within distinct or rare cell types in cancer in vivo has been unattainable. Here we develop INSIGHT by integrating cell sorting with mass spectrometry to enable quantitative phosphoproteomics and proteomics of discrete cell types from fixed tissues. Using INSIGHT, we map the signaling network within disseminating glioblastoma cells from patient-derived xenografts implanted in mice. Disseminating tumor cells undergo a proteome-wide shift from proliferative to mesenchymal, neural progenitor-like cell states. In parallel, signaling network and global kinase activity are rewired, transitioning from cell cycle-associated circuitries to those governing synaptic function, neuronal migration, and ion channel activity. Changes begin at the tumor margin and persist in distant brain parenchyma. Hornerin and phosphorylation of Ca&#xb2;&#x207a;-permeable GluA2 at Y876 were identified as mediators of glioblastoma progression. INSIGHT enables systems-level dissection of cell-type-specific signaling circuitries in vivo across wide range of biological systems.

Glioblastoma

Inflammatory cell death and monocyte dysfunction in VEXAS syndrome.

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a severe adult-onset autoinflammatory disease caused by somatic mutations in the UBA1 gene, disrupting cytoplasmic ubiquitin-activating enzyme E1 function in hematopoietic progenitors. Its pathogenesis remains poorly understood, particularly the mechanisms by which UBA1 mutations disrupt myeloid cell function in the context of inflammatory stimuli. Here, we combine a genetically engineered THP-1 monocytic model with ex vivo analyses of blood and tissue samples from patients with VEXAS syndrome to investigate the consequences of the canonical UBA1M41V mutation. We show that UBA1-mutated monocytes exhibit tumor necrosis factor &#x3b1; (TNF-&#x3b1;)-induced cell death, characterized by receptor-interacting serine/threonine-protein kinase 1 (RIPK1) phosphorylation, and mixed lineage kinase domain-like- and caspase-8-mediated cell death. Importantly, we extend these findings to patient-derived CD14+ sorted cells, confirming that these cells undergo aberrant apoptotic and necroptotic cell death. Mechanistically, activation of these cell death pathways appears to be promoted by defective NF-&#x3ba;B-dependent transcriptional responses and reduced cFLIP(L) expression following TNF-&#x3b1; stimulation. UBA1-mutated monocytes also display blunted cytokine responses to Toll-like receptor (TLR) agonists despite preserved TLR expression, linked to an impaired NF-&#x3ba;B response. UBA1M41V-derived macrophages exhibit a proinflammatory transcriptional profile with increased chemokine secretion that promotes monocyte recruitment. In addition, these UBA1-mutated macrophages display impaired efferocytosis due to lysosomal dysfunction. Together, these findings reveal a pathogenic axis in VEXAS syndrome linking UBA1 loss of function and defective ubiquitination to RIPK1-mediated inflammatory cell death, impaired antimicrobial signaling, and defective resolution mechanisms. Our study provides novel mechanistic insights into the myeloid dysfunction underlying inflammation and cytopenia in VEXAS syndrome and supports the therapeutic targeting of inflammatory cell death pathways.

Humans