Publications by authors named "Kirsten Fairfax"

Recent advances in gene therapy and gene-editing techniques offer the very real potential for successful treatment of neurological diseases. However, drug delivery constraints continue to impede viable therapeutic interventions targeting the brain due to its anatomical complexity and highly restrictive microvasculature that is impervious to many molecules. Realizing the therapeutic potential of gene-based therapies requires robust encapsulation and safe and efficient delivery to the target cells.

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Intracellular flow cytometry is a powerful technique that can be used to interrogate signalling in rare cellular populations. The strengths of the technique are that massively parallel readouts can be gained from thousands of single cells simultaneously, and the assay is fast and relatively straightforward. This plate-based protocol enables different doses and different timepoints of stimulation to be assessed and has been optimized for rare B cell populations.

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Human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) hold promise for transplantation medicine. Diverse human leukocyte antigen (HLA) profiles necessitate autologous cells or multiple cell lines for therapeutics, incurring time and cost. Advancements in CRISPR-Cas9 and cellular therapies have led to the conceptualization of "off-the-shelf" universal cell donor lines, free of immune rejection.

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The use of genomics is firmly established in clinical practice, resulting in innovations across a wide range of disciplines such as genetic screening, rare disease diagnosis and molecularly guided therapy choice. This new field of genomic medicine has led to improvements in patient outcomes. However, most clinical applications of genomics rely on information generated from bulk approaches, which do not directly capture the genomic variation that underlies cellular heterogeneity.

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Purpose: Patients with an underlying telomere biology disorder (TBD) have variable clinical presentations, and they can be challenging to diagnose clinically. A genomic diagnosis for patients presenting with TBD is vital for optimal treatment. Unfortunately, many variants identified during diagnostic testing are variants of uncertain significance.

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The role of B-cell-activating factor (BAFF) in B-lymphocyte biology has been comprehensively studied, but its contributions to innate immunity remain unclear. Natural killer (NK) cells form the first line of defense against viruses and tumors, and have been shown to be defective in patients with systemic lupus erythematosus (SLE). The link between BAFF and NK cells in the development and progression of SLE remains unstudied.

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The human immune system displays substantial variation between individuals, leading to differences in susceptibility to autoimmune disease. We present single-cell RNA sequencing (scRNA-seq) data from 1,267,758 peripheral blood mononuclear cells from 982 healthy human subjects. For 14 cell types, we identified 26,597 independent cis-expression quantitative trait loci (eQTLs) and 990 trans-eQTLs, with most showing cell type-specific effects on gene expression.

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Inflammation is a natural defence mechanism of the body to protect against pathogens. It is induced by immune cells, such as macrophages and neutrophils, which are rapidly recruited to the site of infection, mediating host defence. The processes for eliminating inflammatory cells after pathogen clearance are critical in preventing sustained inflammation, which can instigate diverse pathologies.

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A classical view of blood cell development is that multipotent hematopoietic stem and progenitor cells (HSPCs) become lineage-restricted at defined stages. Linc-KitSca-1Flt3 cells, termed lymphoid-primed multipotent progenitors (LMPPs), have lost megakaryocyte and erythroid potential but are heterogeneous in their fate. Here, through single-cell RNA sequencing, we identify the expression of Dach1 and associated genes in this fraction as being coexpressed with myeloid/stem genes but inversely correlated with lymphoid genes.

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This article summarises recent advances reported at the 9th Lorne Infection and Immunity Conference. This exciting conference hosted speakers in the fields of innate and adaptive responses to infection including host-pathogen interactions as well as novel strategies for the detection, control and treatment of infectious diseases such as fluorescent antibiotics and vaccine development. Host-pathogen studies focused on a broad range of pathogens including malaria, CMV, influenza, dengue and Zika viruses, listeria and tuberculosis.

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During haematopoiesis, haematopoietic stem cells differentiate into restricted potential progenitors before maturing into the many lineages required for oxygen transport, wound healing and immune response. We have updated Haemopedia, a database of gene-expression profiles from a broad spectrum of haematopoietic cells, to include RNA-seq gene-expression data from both mice and humans. The Haemopedia RNA-seq data set covers a wide range of lineages and progenitors, with 57 mouse blood cell types (flow sorted populations from healthy mice) and 12 human blood cell types.

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Eosinophils are important in fighting parasitic infections and are implicated in the pathogenesis of asthma and allergy. IL-5 is a critical regulator of eosinophil development, controlling proliferation, differentiation, and maturation of the lineage. Mice that constitutively express IL-5 have in excess of 10-fold more eosinophils in the hematopoietic organs than their wild type (WT) counterparts.

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In recent years multi-parameter flow cytometry has enabled identification of cells at major stages in myeloid development; from pluripotent hematopoietic stem cells, through populations with increasingly limited developmental potential (common myeloid progenitors and granulocyte-macrophage progenitors), to terminally differentiated mature cells. Myeloid progenitors are heterogeneous, and the surface markers that define transition states from progenitors to mature cells are poorly characterized. Siglec-F is a surface glycoprotein frequently used in combination with IL-5 receptor alpha (IL5Rα) for the identification of murine eosinophils.

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New combination immunotherapies are displaying both efficacy and immune-related adverse events (irAE) in humans. However, grade 3/4 irAEs occur in a high proportion, which can lead to discontinuation of treatment and can result in fatalities if not promptly treated. Prolonged T regulatory cell (Treg) depletion in tumor-bearing Foxp3-DTR mice using diphtheria toxin (DT) mirrored the spectrum of antitumor responses and severity of irAEs that can occur in ipilimumab/nivolumab-treated patients.

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Hematopoiesis is a multistage process involving the differentiation of stem and progenitor cells into distinct mature cell lineages. Here we present Haemopedia, an atlas of murine gene-expression data containing 54 hematopoietic cell types, covering all the mature lineages in hematopoiesis. We include rare cell populations such as eosinophils, mast cells, basophils, and megakaryocytes, and a broad collection of progenitor and stem cells.

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E proteins and their antagonists, the Id proteins, are transcriptional regulators important for normal hematopoiesis. We found that Id2 acts as a key regulator of leukemia stem cell (LSC) potential in MLL-rearranged acute myeloid leukemia (AML). Low endogenous Id2 expression is associated with LSC enrichment while Id2 overexpression impairs MLL-AF9-leukemia initiation and growth.

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We examined the role of NFκB1 in the homeostasis and function of peripheral follicular (Fo) B cells. Aging mice lacking NFκB1 (Nfκb1(-/-)) develop lymphoproliferative and multiorgan autoimmune disease attributed in large part to the deregulated activity of Nfκb1(-/-)Fo B cells that produce excessive levels of the proinflammatory cytokine interleukin 6 (IL-6). Despite enhanced germinal center (GC) B cell differentiation, the formation of GC structures was severely disrupted in the Nfκb1(-/-)mice.

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B cell activating factor of the tumor necrosis factor family (BAFF or BLyS) is a critical factor for B cell survival and maturation. BAFF-transgenic (BAFF-Tg) mice develop autoimmunity that resembles systemic lupus erythematosus (SLE) in a T cell-independent but MyD88-dependent manner, implicating toll-like receptor (TLR) signaling. The specific B cell subtypes that make pro-inflammatory autoantibodies in BAFF-Tg mice are TLR-activated innate B cells known as marginal zone (MZ) and B1 B cells.

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B cell-activating factor of the TNF family (BAFF) is an essential B cell survival factor. However, high levels of BAFF promote systemic lupus erythematosus (SLE) in mice and humans. Belimumab (anti-human BAFF) limits B cell survival and is approved for use in patients with SLE.

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Post-transcriptional regulation of mRNA by the RNA-binding protein HuR (encoded by Elavl1) is required in B cells for the germinal center reaction and for the production of class-switched antibodies in response to thymus-independent antigens. Transcriptome-wide examination of RNA isoforms and their abundance and translation in HuR-deficient B cells, together with direct measurements of HuR-RNA interactions, revealed that HuR-dependent splicing of mRNA affected hundreds of transcripts, including that encoding dihydrolipoamide S-succinyltransferase (Dlst), a subunit of the 2-oxoglutarate dehydrogenase (α-KGDH) complex. In the absence of HuR, defective mitochondrial metabolism resulted in large amounts of reactive oxygen species and B cell death.

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Aicda is a critical component of antibody class-switching in B cells. In this work, we study the impact of TLR4 activation and IL-10 stimulation on Aicda expression in B cells. Through the global analysis of miRNAs in response to TLR4 activation, in combination with IL-10 stimulation, we identified that IL-10 can suppress TLR4-induced miR-155 expression, an effect that resulted in enhanced Aicda expression.

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Maintenance of an appropriate number of plasma cells, long-lived antibody-producing cells that are derived from B cells, is essential for maintaining immunological memory while limiting disease. Plasma cell survival relies on extrinsic factors, the limited availability of which determines the size of the plasma cell population. Mice deficient in the nonreceptor tyrosine kinase Lyn are prone to an autoimmune disease that is characterized by inflammation and an excess of plasma cells (plasmacytosis).

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CD19 is a co-stimulatory surface protein expressed exclusively on B cells and serves to reduce the threshold for signalling via the B-cell receptor (BCR). Co-ligation of CD19 with the BCR synergistically enhances mitogen-activated protein (MAP) kinase activity, calcium release and proliferation. We recently found that these parameters were also enhanced in CD19-null primary murine B cells following BCR ligation, suggesting a regulatory role for CD19 in BCR signalling.

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The various mechanisms that have been described for immune tolerance govern our ability to control self-reactivity and minimize autoimmunity. However, the capacity to genetically manipulate the immune system provides a powerful avenue to supplement this natural tolerance in an Ag-specific manner. We have previously shown in the mouse model of experimental autoimmune encephalomyelitis that transfer of bone marrow (BM) transduced with retrovirus encoding myelin oligodendrocyte glycoprotein (MOG) promotes disease resistance and CD4(+) T cell deletion within the thymus.

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Activation-induced cell death (AICD) plays a critical role in immune homeostasis and tolerance. In T-cell-dependent humoral responses, AICD of B cells is initiated by Fas ligand (FasL) on T cells, stimulating the Fas receptor on B cells. In contrast, T-cell-independent B cell responses involve innate-type B lymphocytes, such as marginal zone (MZ) B cells, and little is known about the mechanisms that control AICD during innate B cell responses to Toll-like receptor (TLR) activation.

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