Biology subjects

Opzoomer, J. W.

Publications and source records attributed to Opzoomer, J. W..

5 recordsLinked to original sources

bioRxiv2026

Scalable variant-to-function screens using prime editing perturb-seq

Linking genetic variants to their functional consequences at scale remains a major challenge in human genetics. Perturb-seq is limited in the variants it can install, while prime editing has largely been restricted to simpler mechanistic readouts. Here, we introduce prime editing perturb-seq (PEP-seq), which links programmed mutations to transcriptomic states. We designed 2,164 prime editing guides targeting common expression quantitative trait loci (eQTLs), premature termination codons, and position-matched synonymous controls, generating 749,110 time-resolved single-cell transcriptomes. PEP-seq precisely detected nonsense-mediated decay, while probe-based junction measurements suggested depletion of mature RNAs. For eQTLs, a locus-size-corrected specificity metric showed that the intended target was frequently the most affected transcript within a 1 Mb window, with effects also associated with open chromatin near the edit site. These results establish PEP-seq as a scalable platform for direct, endogenous variant-to-function mapping.

genomics↗

bioRxiv2024

SIGNAL-seq: Multimodal Single-cell Inter- and Intra-cellular Signalling Analysis

We present SIGNAL-seq (Split-pool Indexing siG-Nalling AnaLysis by sequencing): a multiplexed splitpool combinatorial barcoding method that simultaneously measures RNA and post-translational modifications (PTMs) in fixed single cells from 3D models. SIGNAL-seq PTM measurements are equivalent to mass cytometry and RNA gene detection is analogous to split-pool barcoding scRNA-seq. By measuring both mRNA ligand-receptor pairs and PTMs in single cells, SIGNAL-seq can simultaneously uncover inter- and intra-cellular regulation of tumour microenvironment plasticity.

cancer biology↗

bioRxiv2022

Perivascular macrophages collaborate to facilitate chemotherapy resistance in cancer

A subset of tumor associated macrophages (TAMs) identified by their expression of the lymphatic vessel endothelial hyaluronan receptor-1 (Lyve-1) reside proximal to blood vasculature and contribute to disease progression. Using a spontaneous murine model of mammary adenocarcinoma (MMTV-PyMT), we show that Lyve-1+ TAMs, which co-express heme oxygenase-1, form coordinated multi-cellular nest structures in the perivascular niche. We show that TAM nest formation is dependent on IL-6 and a communication axis involving CCR5 and its cognate ligands CCL3/4. We demonstrate that Lyve-1+ TAM nests are associated with CD8+ T-cell exclusion from the tumor and the resistance to immune-stimulating chemotherapeutics. This study highlights an unappreciated collaboration between TAMs and uncovers a spatially driven therapeutic resistance mechanism of these cells in cancer which can be therapeutically targeted.

cancer biology↗

bioRxiv2020

Lyve-1 expressing perivascular macrophages orchestrate pericyte expansion to sustain angiogenesis in cancer

Tumor associated macrophages (TAMs) are a highly plastic stromal cell type which support cancer progression. Using single-cell RNA-sequencing of TAMs from a spontaneous murine model of mammary adenocarcinoma (MMTV-PyMT) we characterize a subset of these cells expressing lymphatic vessel endothelial hyaluronic acid receptor 1 (Lyve-1) which spatially reside proximal to blood vasculature. We demonstrate that Lyve-1+ TAMs support tumor growth and identify a pivotal role for these cells in maintaining a population of perivascular mesenchymal cells which express alpha-smooth muscle actin and phenotypically resemble pericytes. Using photolabeling techniques show that mesenchymal cells maintain their prevalence in the growing tumor through proliferation and uncover a role for Lyve-1+ TAMs in orchestrating a selective platelet-derived growth factor-CC-dependent expansion of the perivascular mesenchymal population, creating a pro-angiogenic niche. This study highlights the inter-reliance of the immune and non-immune stromal network which support cancer progression and provides therapeutic opportunities for tackling the disease.

cancer biology↗

bioRxiv2020

ImmunoCluster: A computational framework for the non-specialist to immune profile cellular heterogeneity using liquid and imaging mass, and flow cytometry datasets

High dimensional cytometry is an innovative tool for immune monitoring in health and disease, it has provided novel insight into the underlying biology as well as biomarkers for a variety of diseases. However, the analysis of multiparametric "big data" usually requires specialist computational knowledge. Here we describe ImmunoCluster (https://github.com/kordastilab/ImmunoCluster) an R package for immune profiling cellular heterogeneity in high dimensional liquid and imaging mass cytometry, and flow cytometry data, designed to facilitate computational analysis by a non-specialist. The analysis framework implemented within ImmunoCluster is readily scalable to millions of cells and provides a variety of visualization and analytical approaches, as well as a rich array of plotting tools that can be tailored to users needs. The protocol consists of three core computational stages: 1, data import and quality control, 2, dimensionality reduction and unsupervised clustering; and 3, annotation and differential testing, all contained within an R-based open-source framework.

systems biology↗