Publications by authors named "Aziz Al' Khafaji"

Article Synopsis
  • Single-cell RNA sequencing (scRNA-seq) is a valuable technique for understanding how gene variations affect RNA expression in individual cells, and allele-specific expression (ASE) analysis enhances this understanding by focusing on genetic differences at the RNA level.* -
  • The study reveals that using single-nucleus RNA-seq (snRNA-seq) can improve analysis of ASE due to increased intronic reads, which are more likely to contain genetic variants, and demonstrates how experimental factors like RNA source and sequencing depth can influence the effectiveness of these analyses.* -
  • The researchers developed new computational tools and compared their ASE methods against traditional expression quantitative trait locus (eQTL) analysis in a Parkinson's disease study, finding that ASE analysis was
View Article and Find Full Text PDF

This study introduces a novel, cost-effective, and rapid method for identifying hemorrhage or leakage sites following postoperative deaths, a critical aspect in the context of medical malpractice litigation. The technique employs diluted ink as an injectable dye, providing an alternative to postmortem contrast imaging. The utility of this method was demonstrated through a series of three cases.

View Article and Find Full Text PDF

Gene fusions are found as cancer drivers in diverse adult and pediatric cancers. Accurate detection of fusion transcripts is essential in cancer clinical diagnostics, prognostics, and for guiding therapeutic development. Most currently available methods for fusion transcript detection are compatible with Illumina RNA-seq involving highly accurate short read sequences.

View Article and Find Full Text PDF

Single-cell transcriptomics has become the definitive method for classifying cell types and states, and can be augmented with genotype information to improve cell lineage identification. Due to constraints of short-read sequencing, current methods to detect natural genetic barcodes often require cumbersome primer panels and early commitment to targets. Here we devise a flexible long-read sequencing workflow and analysis pipeline, termed nanoranger, that starts from intermediate single-cell cDNA libraries to detect cell lineage-defining features, including single-nucleotide variants, fusion genes, isoforms, sequences of chimeric antigen and TCRs.

View Article and Find Full Text PDF
Article Synopsis
  • Long-read RNA-sequencing methods can capture full transcript isoforms but traditionally have low throughput*. -
  • The new technique, multiplexed arrays isoform sequencing (MAS-ISO-seq), enhances this by combining cDNAs for more efficient long-read sequencing, boosting throughput by over 15 times*. -
  • In experiments with tumor-infiltrating T cells, MAS-ISO-seq led to a significant increase (12- to 32-fold) in the identification of differentially spliced genes*.
View Article and Find Full Text PDF

Systematic evaluation of the impact of genetic variants is critical for the study and treatment of human physiology and disease. While specific mutations can be introduced by genome engineering, we still lack scalable approaches that are applicable to the important setting of primary cells, such as blood and immune cells. Here, we describe the development of massively parallel base-editing screens in human hematopoietic stem and progenitor cells.

View Article and Find Full Text PDF

Stimulator of interferon genes (STING) is an intracellular sensor of cyclic di-nucleotides involved in the innate immune response against pathogen- or self-derived DNA. STING trafficking is tightly linked to its function, and its dysregulation can lead to disease. Here, we systematically characterize genes regulating STING trafficking and examine their impact on STING-mediated responses.

View Article and Find Full Text PDF

Regulatory relationships between transcription factors (TFs) and their target genes lie at the heart of cellular identity and function; however, uncovering these relationships is often labor-intensive and requires perturbations. Here, we propose a principled framework to systematically infer gene regulation for all TFs simultaneously in cells at steady state by leveraging the intrinsic variation in the transcriptional abundance across single cells. Through modeling and simulations, we characterize how transcriptional bursts of a TF gene are propagated to its target genes, including the expected ranges of time delay and magnitude of maximum covariation.

View Article and Find Full Text PDF

The therapeutic landscape across many cancers has dramatically improved since the introduction of potent targeted agents and immunotherapy. Nonetheless, success of these approaches is too often challenged by the emergence of therapeutic resistance, fueled by intratumoral heterogeneity and the immense evolutionary capacity inherent to cancers. To date, therapeutic strategies have attempted to outpace the evolutionary tempo of cancer but frequently fail, resulting in lack of tumor response and/or relapse.

View Article and Find Full Text PDF

The ability to track and isolate unique cell lineages from large heterogeneous populations increases the resolution at which cellular processes can be understood under normal and pathogenic states beyond snapshots obtained from single-cell RNA sequencing (scRNA-seq). Here, we describe the Control of Lineages by Barcode Enabled Recombinant Transcription (COLBERT) method in which unique single guide RNA (sgRNA) barcodes are used as functional tags to identify and recall specific lineages of interest. An sgRNA barcode is stably integrated and actively transcribed, such that all cellular progeny will contain the parental barcode and produce a functional sgRNA.

View Article and Find Full Text PDF
Article Synopsis
  • ClonMapper is a new lineage-tracing system that combines DNA barcoding, single-cell RNA sequencing, and clonal isolation for detailed analysis of complex cell populations.
  • This tool helped researchers identify distinct subpopulations within a chronic lymphocytic leukemia cell line, revealing unique genetic and survival characteristics.
  • ClonMapper's ability to monitor clones throughout treatment allows for a deeper understanding of tumor evolution and how different cell groups respond to therapy.
View Article and Find Full Text PDF

Treatment-persistent residual tumors impede curative cancer therapy. To understand this cancer cell state we generated models of treatment persistence that simulate the residual tumors. We observe that treatment-persistent tumor cells in organoids, xenografts, and cancer patients adopt a distinct and reversible transcriptional program resembling that of embryonic diapause, a dormant stage of suspended development triggered by stress and associated with suppressed Myc activity and overall biosynthesis.

View Article and Find Full Text PDF

A significant challenge in the field of biomedicine is the development of methods to integrate the multitude of dispersed data sets into comprehensive frameworks to be used to generate optimal clinical decisions. Recent technological advances in single cell analysis allow for high-dimensional molecular characterization of cells and populations, but to date, few mathematical models have attempted to integrate measurements from the single cell scale with other types of longitudinal data. Here, we present a framework that actionizes static outputs from a machine learning model and leverages these as measurements of state variables in a dynamic model of treatment response.

View Article and Find Full Text PDF

Lineage tracking delivers essential quantitative insight into dynamic, probabilistic cellular processes, such as somatic tumor evolution and differentiation. Methods for high diversity lineage quantitation rely on sequencing a population of DNA barcodes. However, manipulation of specific individual lineages is not possible with this approach.

View Article and Find Full Text PDF

Endoplasmic reticulum (ER) stress has been implicated as an initiator or contributing factor in neurodegenerative diseases. The mechanisms that lead to ER stress and whereby ER stress contributes to the degenerative cascades remain unclear but their understanding is critical to devising effective therapies. Here we show that knockdown of Herp (Homocysteine-inducible ER stress protein), an ER stress-inducible protein with an ubiquitin-like (UBL) domain, aggravates ER stress-mediated cell death induced by mutant α-synuclein (αSyn) that causes an inherited form of Parkinson's disease (PD).

View Article and Find Full Text PDF