Biology subjects

Zwack, E. E.

Publications and source records attributed to Zwack, E. E..

5 recordsLinked to original sources

bioRxiv2024

scRNA-seq reveals transcriptional dynamics of Encephalitozoon intestinalis parasites in human macrophages

Microsporidia are single-celled intracellular parasites that cause opportunistic diseases in humans. Encephalitozoon intestinalis is a prevalent human-infecting species that invades the small intestine. Dissemination to other organ systems is also observed, and is potentially facilitated by macrophages. The macrophage response to infection and the developmental trajectory of the parasite are not well studied. Here we use single cell RNA sequencing to investigate transcriptional changes in both the host and parasite during infection. While a small population of infected macrophages mount a response, most remain transcriptionally unchanged, suggesting that the majority of parasites may avoid host detection. The parasite transcriptome reveals large transcriptional changes throughout the life cycle, providing a blueprint for parasite development. The stealthy microsporidian lifestyle likely allows these parasites to harness macrophages for replication and dissemination. Together, our data provide insights into the host response in primary human macrophages and the E. intestinalis developmental program.

microbiology↗

bioRxiv2024

Prophage-encoded methyltransferase drives adaptation of community-acquired methicillin-resistant Staphylococcus aureus

We recently described the evolution of a community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) USA300 variant responsible for an outbreak of skin and soft tissue infections. Acquisition of a mosaic version of the {Phi}11 prophage (m{Phi}11) that increases skin abscess size was an early step in CA-MRSA adaptation that primed the successful spread of the clone. The present report shows how prophage m{Phi}11 exerts its effect on virulence for skin infection without encoding a known toxin or fitness genes. Abscess size and skin inflammation were associated with DNA methylase activity of an m{Phi}11-encoded adenine methyltransferase (designated pamA). pamA increased expression of fibronectin-binding protein A (fnbA; FnBPA), and inactivation of fnbA eliminated the effect of pamA on abscess virulence without affecting strains lacking pamA. Thus, fnbA is a pamA-specific virulence factor. Mechanistically, pamA was shown to promote biofilm formation in vivo in skin abscesses, a phenotype linked to FnBPAs role in biofilm formation. Collectively, these data reveal a novel mechanism--epigenetic regulation of staphylococcal gene expression--by which phage can regulate virulence to drive adaptive leaps by S. aureus. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=84 SRC="FIGDIR/small/589803v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@b97d6forg.highwire.dtl.DTLVardef@1da30f1org.highwire.dtl.DTLVardef@1c34311org.highwire.dtl.DTLVardef@6834df_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2024

Heterozygosity for Crohn's Disease Risk Allele of ATG16L1 Protects against Bacterial Infection

The T300A substitution in ATG16L1 associated with Crohns Disease impairs autophagy, yet up to 50% of humans are heterozygous for this allele. Here we demonstrate that heterozygosity for the analogous substitution in mice (Atg16L1T316A), but not homozygosity, protects against lethal Salmonella enterica Typhimurium infection. One copy of Atg16L1T316A was sufficient to enhance cytokine production through inflammasome activation, which was necessary for protection. In contrast, two copies of Atg16L1T316A inhibited the autophagy-related process of LC3-associated phagocytosis (LAP) and increased susceptibility. Macrophages from human donors heterozygous for ATG16L1T300Adisplayed elevated inflammasome activation while homozygosity impaired LAP, similar to mice. These results clarify how the T300A substitution impacts ATG16L1 function and suggest it can be beneficial to heterozygous carriers, providing an explanation for its prevalence. One-Sentence SummaryHeterozygosity of Crohns diseases risk variant ATG16L1 T300A confers protection against bacterial infections.

immunology↗

bioRxiv2023

Single-cell analysis of CX3CR1+ cells reveal a pathogenic role for BIRC5+ myeloid proliferating cells driven by Staphylococcus aureus leukotoxins

Our previous studies identified a population of stem cell-like proliferating myeloid cells within inflamed tissues that could serve as a reservoir for tissue macrophages to adopt different activation states depending on the microenvironment. By lineage tracing cells derived from CX3CR1+ precursors in mice during infection and profiling by scRNA-seq, here we identify a cluster of BIRC5+ myeloid cells that expanded in the liver during either chronic infection with the parasite Schistosoma mansoni or the bacterial pathogen Staphylococcus aureus. In the absence of tissue damaging toxins, S. aureus infection does not elicit these BIRC5+ cells. Moreover, deletion of BIRC5 from CX3CR1 expressing cells results in improved survival during S. aureus infection. Hence, the combination of scRNA-Seq and genetic fate mapping CX3CR1+ cells revealed a toxin dependent pathogenic role for BIRC5 in myeloid cells during S. aureus infection.

immunology↗

bioRxiv2019

Distinct features of human myeloid cell cytokine response profiles identify neutrophil activation by cytokines as a prognostic feature during tuberculosis and cancer

Myeloid cells are a vital component of innate immunity and comprise of monocytes, macrophages, dendritic cells and granulocytes. How myeloid cell lineage affects activation states in response to cytokines remains poorly understood. The cytokine environment and cellular infiltrate during an inflammatory response may contain prognostic features that could predict disease outcome. Here we analyzed the transcriptional responses of human monocytes, macrophages, dendritic cells and neutrophils in response to stimulation by IFN-{gamma}, IFN-{beta} IFN-{lambda}, IL-4, IL-13 and IL-10 cytokines, to better understand the heterogeneity of activation states in inflammatory conditions. This generated a myeloid cell cytokine specific response matrix that can infer representation of myeloid cells and the cytokine environment they encounter during infection and in tumors. Neutrophils were highly responsive to type 1 and type 2 cytokine stimulation but did not respond to IL-10. We identified transcripts specific to IFN-{beta} stimulation, whereas other IFN signature genes were upregulated by both IFN-{gamma} and IFN-{beta}. When we used our matrix to deconvolute blood profiles from tuberculosis patients, the IFN-{beta} specific neutrophil signature was reduced in TB patients with active disease whereas the shared response to IFN-{gamma} and IFN-{beta} in neutrophils was increased. When applied to glioma patients, transcripts of neutrophils exposed to IL-4 or IL-13 and monocyte responses to IFN-{gamma} or IFN-{beta} emerged as opposing predictors of patient survival. Hence, by dissecting how different myeloid cells respond to cytokine activation, we can delineate biological roles for myeloid cells in different cytokine environments during disease processes, especially during infection and tumor progression.

immunology↗