Scientific Publications

Search and Filter
Last Modified, October 25, 2020
Results per Page: 10
  • 5
  • 10
  • 20
  • 50
  • 100

A Fas-4-1BB fusion protein converts a death to a pro-survival signal and enhances T cell therapy

J Exp Med

2020 Kristin Anderson; Breanna Bates; Patrick Bonson; Cody Jenkins; Shannon Oda; Pranali Ravikumar; Shu Zhuang; Andrew Daman; Philip Greenberg; Nicolas Garcia; Edison Chiu

Adoptive T cell therapy (ACT) with genetically modified T cells has shown impressive results against some hematologic cancers, but efficacy in solid tumors can be limited by restrictive tumor microenvironments (TMEs). For example, Fas ligand is commonly overexpressed in TMEs and induces apoptosis in tumor-infiltrating, Fas receptor-positive lymphocytes. We engineered immunomodulatory fusion proteins (IFPs) to enhance ACT efficacy, combining an inhibitory receptor ectodomain with a costimulatory endodomain to convert negative into positive signals. We developed a Fas-4-1BB IFP that replaces the Fas intracellular tail with costimulatory 4-1BB. Fas-4-1BB IFP-engineered murine T cells exhibited increased pro-survival signaling, proliferation, antitumor function, and altered metabolism in vitro. In vivo, Fas-4-1BB ACT eradicated leukemia and significantly improved survival in the aggressive KPC pancreatic cancer model. Fas-4-1BB IFP expression also enhanced primary human T cell function in vitro. Thus, Fas-4-1BB IFP expression is a novel strategy to improve multiple T cell functions and enhance ACT against solid tumors and hematologic malignancies.

A natural variant of the essential host gene MMS21 restricts the parasitic 2-micron plasmid in Saccharomyces cerevisiae


2020 Michelle Hays; Janet Young; Harmit Malik; Paula Levan

Antagonistic coevolution with selfish genetic elements (SGEs) can drive evolution of host resistance. Here, we investigated host suppression of 2-micron (2m) plasmids, multicopy nuclear parasites that have co-evolved with budding yeasts. We developed SCAMPR (Single-Cell Assay for Measuring Plasmid Retention) to measure copy number heterogeneity and 2m plasmid loss in live cells. We identified three S. cerevisiae strains that lack endogenous 2m plasmids and reproducibly inhibit mitotic plasmid stability. Focusing on the Y9 ragi strain, we determined that plasmid restriction is heritable and dominant. Using bulk segregant analysis, we identified a high-confidence Quantitative Trait Locus (QTL) with a single variant of MMS21 associated with increased 2m instability. MMS21 encodes a SUMO E3 ligase and an essential component of the Smc5/6 complex, involved in sister chromatid cohesion, chromosome segregation, and DNA repair. Our analyses leverage natural variation to uncover a novel means by which budding yeasts can overcome highly successful genetic parasites.

Cytomegalovirus and Epstein-Barr virus viremia are associated with HIV DNA levels in the reservoir of Kenyan infants on antiretroviral therapy

J Infect Dis

2020 Dara Lehman; Mark Pankau

Identifying determinants of HIV reservoir levels may inform novel viral eradication strategies. Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) co-infections were assessed as predictors of HIV proviral DNA level in 26 HIV RNA-suppressed Kenyan children starting antiretroviral therapy (ART) before 7 months of age. Earlier acquisition of CMV and EBV, and higher cumulative burden of systemic EBV DNA viremia were each associated with higher HIV DNA level in the reservoir after 24 months of ART, independent of HIV RNA levels over time. These data suggest delaying or containing CMV and EBV viremia may be novel strategies to limit HIV reservoir formation.

Prediction of Acute Graft versus Host Disease and Relapse by Endogenous Metabolomic Compounds in Patients Receiving Personalized Busulfan-Based Conditioning

J Proteome Res

2020 H. Joachim Deeg; Timothy Randolph; K. Scott Baker

Busulfan-based conditioning is the most commonly used high-dose conditioning regimen for allogeneic hematopoietic cell transplant (HCT). The alkylating agent busulfan has a narrow therapeutic index, with busulfan doses personalized to a target plasma exposure (targeted busulfan). Using a global pharmacometabonomics approach, we sought to identify novel biomarkers of relapse or acute graft versus host disease (GVHD) in a cohort of 84 patients receiving targeted busulfan before allogeneic HCT. A total of 763 endogenous metabolomic compounds (EMCs) were quantitated in 230 longitudinal blood samples before, during, and shortly after intravenous busulfan administration. We performed both univariate linear regression and pathway enrichment analyses using global testing. The cysteine/methionine pathway and the glycine, serine, and threonine metabolism pathway were most associated with relapse. The latter be explained by the fact that glutathione S-transferases conjugate both busulfan and glutathione, which contains glycine as a component. The d-arginine and d-ornithine metabolism pathway and arginine and proline metabolism pathway were most associated with acute GVHD. None of these associations were significant after correcting for false discovery rate (FDR) with a strict cutoff of FDR-adjusted p < 0.1. Although larger studies are needed to substantiate these findings, the results show that EMCs may be used as predictive biomarkers in HCT patients.

In silico benchmarking of metagenomic tools for coding sequence detection reveals the limits of sensitivity and precision

BMC Bioinformatics

2020 Samuel Minot

BACKGROUND: High-throughput sequencing can establish the functional capacity of a microbial community by cataloging the protein-coding sequences (CDS) present in the metagenome of the community. The relative performance of different computational methods for identifying CDS from whole-genome shotgun sequencing is not fully established. RESULTS: Here we present an automated benchmarking workflow, using synthetic shotgun sequencing reads for which we know the true CDS content of the underlying communities, to determine the relative performance (sensitivity, positive predictive value or PPV, and computational efficiency) of different metagenome analysis tools for extracting the CDS content of a microbial community. Assembly-based methods are limited by coverage depth, with poor sensitivity for CDS at <5X depth of sequencing, but have excellent PPV. Mapping-based techniques are more sensitive at low coverage depths, but can struggle with PPV. We additionally describe an expectation maximization based iterative algorithmic approach which we show to successfully improve the PPV of a mapping based technique while retaining improved sensitivity and computational efficiency. CONCLUSION: Our benchmarking approach reveals the trade-offs of assembly versus alignment-based approaches and the relative performance of specific implementations when one wishes to extract the protein coding capacity of microbial communities.

Polyclonal B-cell lymphocytosis in English bulldogs

J Vet Intern Med

2020 Julia Labadie

BACKGROUND: English bulldogs disproportionally develop an expansion of small B-cells, which has been interpreted as B-cell chronic lymphocytic leukemia (BCLL). However, clonality testing in these cases has often not been supportive of neoplasia. HYPOTHESIS: English bulldogs have a syndrome of nonneoplastic B-cell expansion. ANIMALS: Eighty-four English bulldogs with small-sized CD21+ B-cell lymphocytosis in the blood as determined by flow cytometry. METHODS: This is a retrospective study. We characterized this syndrome by assessing B-cell clonality, clinical presentation, flow cytometric features, and immunoglobulin gammopathy patterns. We identified 84 cases with CD21+ lymphocytosis among 195 English bulldogs with blood samples submitted to the Colorado State University-Clinical Immunology laboratory for immunophenotyping between 2010 and 2019. Flow cytometry features were compared to normal B-cells and BCLL cases. PCR for antigen receptor rearrangements (PARR) by multiple immunoglobulin primers was performed to assess B-cell clonality. A subset of cases with gammopathy were examined by protein electrophoresis, immunofixation, and immunoglobulin subclass ELISA quantification. RESULTS: Seventy percent (58/83) of cases had polyclonal or restricted polyclonal immunoglobulin gene rearrangements, suggesting nonmalignant B-cell expansion. The median age of all dogs in the study was 6.8years and 74% were male. The median (range) lymphocyte count was 22400/L (2000-384400/L) and B-cells had low expression of class II MHC and CD25. Splenomegaly or splenic masses were detected in 57% (26/46) of cases and lymphadenopathy in 11% (7/61). Seventy-one percent (52/73) of cases had hyperglobulinemia and 77% (23/30) with globulin characterization had IgAIgM polyclonal or restricted polyclonal gammopathy patterns. CONCLUSIONS AND CLINICAL IMPORTANCE: Polyclonal B-cell lymphocytosis in English bulldogs is characterized by low B-cell class II MHC and CD25 expression, splenomegaly and hyperglobulinemia consisting of increased IgAIgM. We hypothesize that this syndrome has a genetic basis.

Anti-ICOS mAb Targets Pathogenic IL-17A-expressing Cells in Canine Model of Chronic GVHD


2020 Diane Stone; Rainer Storb; Vance Abrams; Noa Granot; Melissa Johnson; Maura Parker

BACKGROUND: Chronic graft-versus-host disease (GVHD) is a significant cause of morbidity and mortality in transplant patients. We have previously shown that 3 doses of an anti-ICOS mAb transiently ameliorated symptoms and extended survival of dogs affected by chronic GVHD over that of control dogs. The purpose of this study was to specifically correlate changes in T-cell populations in the peripheral blood with anti-ICOS treatment and chronic GVHD progression and regression in order to reach a better understanding of the mechanism of the disease and prioritize future studies. METHODS: Peripheral blood cells from canines transplanted with DLA-mismatched bone marrow and PBMC to generate chronic GVHD were analyzed by flow cytometry using a panel of antibodies specific to helper and cytolytic T cells. RESULTS: Chronic GVHD was specifically associated with an increase in CD4ICOS cells, ICOS cells expressing IL-17A, and CD8 cells generating granzyme B. Treatment with anti-ICOS mAb at onset of chronic GVHD symptoms specifically targeted IL-17A-expressing cells, transiently relieved symptoms, and lengthened survival but was unable to reduce the percentage of CD8 T-cells expressing granzyme B. CONCLUSIONS: These studies suggested a role for both CD4 and CD8 T cells in pathogenesis of chronic GVHD in the canine model. We propose that future studies should focus on further extending survival by developing a treatment that would control both CD4 and CD8 T cells.

Comparative host-coronavirus protein interaction networks reveal pan-viral disease mechanisms


2020 Melody Campbell

The COVID-19 (Coronavirus disease-2019) pandemic, caused by the SARS-CoV-2 coronavirus, is a significant threat to public health and the global economy. SARS-CoV-2 is closely related to the more lethal but less transmissible coronaviruses SARS-CoV-1 and MERS-CoV. Here, we have carried out comparative viral-human protein-protein interaction and viral protein localization analysis for all three viruses. Subsequent functional genetic screening identified host factors that functionally impinge on coronavirus proliferation, including Tom70, a mitochondrial chaperone protein that interacts with both SARS-CoV-1 and SARS-CoV-2 Orf9b, an interaction we structurally characterized using cryo-EM. Combining genetically-validated host factors with both COVID-19 patient genetic data and medical billing records identified important molecular mechanisms and potential drug treatments that merit further molecular and clinical study.

Clinical response to immune checkpoint inhibition in patients with advanced skin cancers receiving concurrent ruxolitinib therapy for hematologic malignancy

Br J Dermatol

2020 Shailender Bhatia

Patients who are being treated with Janus-Kinase (JAK) inhibitors for hematologic conditions have a higher risk of developing non-melanoma skin cancers (NMSC) with an aggressive course1,2 . This has been attributed to relative immune-suppression that can accompany the use of JAK inhibitors, from their effects on T-cell signaling pathways3 . Acquired inactivating mutations in JAK 1 and JAK 2 genes have been reported to lead to a loss of programmed death ligand-1 (PD-L1) expression and a lack of response to interferon-γ (IFN-γ) in melanoma, contributing to acquired resistance to anti-programmed death 1 (PD-1) treatment4 .

Road Map to Safe and Well-Designed De-escalation Trials of Systemic Adjuvant Therapy for Solid Tumors

J Clin Oncol

2020 Nancy Davidson

An important challenge in the field of cancer is finding the balance between delivering effective treatments and avoiding adverse effects and financial toxicity caused by innovative, yet expensive, drugs. To address this, several treatment de-escalation trials have been conducted, but only a few of these have provided clear answers. A few trials had poor accrual or had design flaws that led to conflicting results. Members of the Breast International Group (BIG) and North American Breast Cancer Group (NABCG) believe the way forward is to understand the lessons from these trials and listen more carefully to what truly matters to our patients. We reviewed several adjuvant trials of different cancer types and developed a road map for improving the design and implementation of future de-escalation trials. The road map incorporates patients' insights obtained through focused group discussions across the BIG-NABCG networks. Considerations for the development of de-escalation trials for systemic adjuvant treatment, including noninferiority trial design, choice of end points, and prioritization of a patient's perspectives, are presented in this consensus article.

Last Modified, February 20, 2020