Biology subjects

Basom, R.

Publications and source records attributed to Basom, R..

6 recordsLinked to original sources

bioRxiv2026

Coordinated expansion of CD163⁺ monocytes and immature CD177⁺ neutrophils marks severe neurotoxicity after CD19 CAR T cell therapy

Immune effector cell-associated neurotoxicity syndrome (ICANS) is a major complication after CAR T cell therapy, but its underlying mechanisms remain poorly understood. We performed longitudinal immune profiling of paired whole blood and serum samples from patients with relapsed or refractory diffuse large B cell lymphoma (DLBCL) treated with CD19 CAR T cells. At peak neurotoxicity, high-dimensional mass cytometry and serum proteomics identified the expansion of CD163 monocytes and immature CD10lowCD101low neutrophils correlated with elevated serum ST2 and IL-2RA concentrations. Integrative immune module analysis identified these features among the strongest predictors of ICANS severity. Independent single-cell transcriptomic profiling validated the emergence of immunoregulatory CD163 monocytes and identified CD177 as a biomarker of ICANS-associated immature neutrophils. Together, these findings reveal a coordinated myeloid inflammatory network associated with ICANS and nominate candidate biomarkers and therapeutic targets for improving the safety of CAR T cell therapy. SignificanceWe demonstrate that immunoregulatory CD163+ monocytes and immature, activated CD177hiCD10lowCD101low neutrophils emerge in patients with moderate to severe ICANS at peak toxicity following CD19 CAR T cell therapy. These findings identify an uncharacterized myeloid network potentially contributing towards ICANS pathogenesis.

immunology↗

bioRxiv2020

Phage-DMS: a comprehensive method for fine mapping of antibody epitopes

Understanding the antibody response is critical to developing vaccine and antibody-based therapies and has inspired the recent development of new methods to isolate antibodies. However, methods to define the antibody-antigen interactions that determine specificity or allow escape have not kept pace. We developed Phage-DMS, a method which combines two powerful approaches - immunoprecipitation of phage peptide libraries and deep mutational scanning (DMS) - to enable high-throughput fine mapping of antibody epitopes. As an example, we designed sequences encoding all possible amino acid variants of HIV Envelope to create phage display libraries. Using Phage-DMS, we identified sites of escape predicted using other approaches for four well characterized HIV monoclonal antibodies with known linear epitopes. In some cases, the results of Phage-DMS refined the epitope beyond what was determined in previous studies. This method has the potential to rapidly and comprehensively screen many antibodies in a single experiment to define sites essential for binding to antigen.

immunology↗

bioRxiv2018

N6-methyladenosine mRNA marking promotes selective translation of regulons required for human erythropoiesis

Many of the regulatory features governing erythrocyte specification, maturation, and associated disorders remain enigmatic. To identify new regulators of erythropoiesis, we performed a functional genomic screen for genes affecting expression of the erythroid marker CD235a/GYPA. Among validating hits were genes coding for the N6-methyladenosine (m6A) mRNA methyltransferase (MTase) complex, including, METTL14, METTL3, and WTAP. We found that m6A MTase activity promotes erythroid gene expression programs and lineage specification through selective translation of >200 m6A marked mRNAs, including those coding for SETD methyltransferase, ribosome, and polyA RNA binding proteins. Remarkably, loss of m6A marks resulted in dramatic loss of H3K4me3 across key erythroid-specific KLF1 transcriptional targets (e.g., Heme biosynthesis genes). Further, each m6A MTase subunit and a subset of their mRNAs targets, including BRD7, CXXC1, PABPC1, PABPC4, STK40, and TADA2B, were required for erythroid specification. Thus, m6A mRNA marks promote the translation of a network of genes required for human erythropoiesis.

cell biology↗

bioRxiv2018

Connect-seq to superimpose molecular on anatomical neural circuit maps

The mouse brain contains ~100 million neurons interconnected in a vast array of neural circuits. The identities and functions of individual neuronal components of most circuits are undefined. Here we describe a method, termed Connect-seq, which combines retrograde viral tracing and single cell transcriptomics to uncover the molecular identities of upstream neurons in a specific circuit and the signaling molecules they use to communicate. Connect-seq can generate a molecular map that can be superimposed on a neuroanatomical map to permit molecular and genetic interrogation of how the neuronal components of a circuit control its function. Application of this method to hypothalamic neurons controlling physiological responses to fear and stress reveal subsets of upstream neurons that express diverse constellations of signaling molecules and can be distinguished by their anatomical locations.

neuroscience↗

bioRxiv2018

CRISPR-Cas9 Screens Reveal Genes Regulating a G0-like State in Human Neural Progenitors

Single cell RNA-seq has emerged as a powerful tool for resolving cellular states associated with normal and maligned developmental processes. Here, we used scRNA-seq to examine the cell cycle states of expanding human neural stem cells (hNSCs). From this data, we created a cell cycle classifier, which, in addition to traditional cell cycle phases, also identifies a putative quiescent-like state in neuroepithelial-derived cell types during mammalian neurogenesis and in gliomas. This state, Neural G0, is enriched for expression of quiescent NSC genes and other neurodevelopmental markers found in non-dividing neural progenitors. For gliomas, Neural G0 cell populations and gene expression is significantly associated with less aggressive tumors and extended patient survival. Genetic screens to identify modulators of Neural G0 revealed that knockout of genes associated with the Hippo/Yap and p53 pathways diminished Neural G0 in vitro, resulting in faster G1 transit, down regulation of quiescence-associated markers, and loss of Neural G0 gene expression. Thus, Neural G0 represents a dynamic quiescent-like state found in neuro-epithelial derived cells and gliomas.

cell biology↗

bioRxiv2018

A Virus-Packageable CRISPR Screen Identifies Host Factors Mediating Interferon Inhibition of HIV

Interferon (IFN) inhibits HIV replication by inducing an array of antiviral effectors. Here we describe a novel CRISPR knockout screening approach to identify the ensemble of these HIV restriction factors. We assembled a CRISPR sgRNA library specific for Interferon Stimulated Genes (ISGs) into a modified lentiviral vector that allows for packaging of sgRNA-encoding genomes in trans into budding HIV-1 particles. We observed that knockout of Zinc Antiviral Protein (ZAP) improved the performance of the screen due to ZAP-mediated inhibition of the vector. We identify a small panel of IFN-induced HIV restriction factors, including MxB, IFITM1, Tetherin/BST2 and TRIM5 which together explain the inhibitory effects of IFN on the HIV-1 LAI strain in THP-1 cells. Further, we identify novel HIV dependency factors, including SEC62 and TLR2. The ability of IFN-induced restriction factors to inhibit an HIV strain to replicate in human cells suggests that these human restriction factors are incompletely antagonized.

microbiology↗