SLC6A3 and body mass index in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial

<p>Abstract</p> <p>Background</p> <p>To investigate the contribution of the dopamine transporter to dopaminergic reward-related behaviors and anthropometry, we evaluated associations between polymorphisms at the dopamine transporter gene(<it>SLC6A3</it>) and body mass index (BMI), among participants in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial.</p> <p>Methods</p> <p>Four polymorphisms (rs6350, rs6413429, rs6347 and the 3' variable number of tandem repeat (3' VNTR) polymorphism) at the <it>SLC6A3 </it>gene were genotyped in 2,364 participants selected from the screening arm of PLCO randomly within strata of sex, age and smoking history. Height and weight at ages 20 and 50 years and baseline were assessed by questionnaire. BMI was calculated and categorized as underweight, normal, overweight and obese (<18.5, 18.5–24.9, 25.0–29.9, or ≥ 30 kg/m², respectively). Odds ratios (ORs) and 95% confidence intervals (CIs) of <it>SLC6A3 </it>genotypes and haplotypes were computed using conditional logistic regression.</p> <p>Results</p> <p>Compared with individuals having a normal BMI, obese individuals at the time of the baseline study questionnaire were less likely to possess the <it>3' </it>VNTR variant allele with 9 copies of the repeated sequence in a dose-dependent model (** is referent; OR_*9= 0.80, OR₉₉= 0.47, p_trend= 0.005). Compared with individuals having a normal BMI at age 50, overweight individuals (A-C-G-* is referent; OR_A-C-G-9= 0.80, 95% CI 0.65–0.99, p = 0.04) and obese individuals (A-C-G-* is referent; OR_A-C-G-9= 0.70, 95% CI 0.49–0.99, p = 0.04) were less likely to possess the haplotype with the 3'variant allele (A-C-G-9).</p> <p>Conclusion</p> <p>Our results support a role of genetic variation at the dopamine transporter gene, <it>SLC6A3</it>, as a modifier of BMI.</p

Absence of Colony Stimulation Factor-1 Receptor Results in Loss of Microglia, Disrupted Brain Development and Olfactory Deficits

The brain contains numerous mononuclear phagocytes called microglia. These cells express the transmembrane tyrosine kinase receptor for the macrophage growth factor colony stimulating factor-1 (CSF-1R). Using a CSF-1R-GFP reporter mouse strain combined with lineage defining antibody staining we show in the postnatal mouse brain that CSF-1R is expressed only in microglia and not neurons, astrocytes or glial cells. To study CSF-1R function we used mice homozygous for a null mutation in the Csflr gene. In these mice microglia are >99% depleted at embryonic day 16 and day 1 post-partum brain. At three weeks of age this microglial depletion continues in most regions of the brain although some contain clusters of rounded microglia. Despite the loss of microglia, embryonic brain development appears normal but during the post-natal period the brain architecture becomes perturbed with enlarged ventricles and regionally compressed parenchyma, phenotypes most prominent in the olfactory bulb and cortex. In the cortex there is increased neuronal density, elevated numbers of astrocytes but reduced numbers of oligodendrocytes. Csf1r nulls rarely survive to adulthood and therefore to study the role of CSF-1R in olfaction we used the viable null mutants in the Csf1 (Csf1op) gene that encodes one of the two known CSF-1R ligands. Food-finding experiments indicate that olfactory capacity is significantly impaired in the absence of CSF-1. CSF-1R is therefore required for the development of microglia, for a fully functional olfactory system and the maintenance of normal brain structure

Deletion of a Csf1r enhancer selectively impacts CSF1R expression and development of tissue macrophage populations.

The proliferation, differentiation and survival of mononuclear phagocytes depend on signals from the receptor for macrophage colony-stimulating factor, CSF1R. The mammalian Csf1r locus contains a highly conserved super-enhancer, the fms-intronic regulatory element (FIRE). Here we show that genomic deletion of FIRE in mice selectively impacts CSF1R expression and tissue macrophage development in specific tissues. Deletion of FIRE ablates macrophage development from murine embryonic stem cells. Csf1r mice lack macrophages in the embryo, brain microglia and resident macrophages in the skin, kidney, heart and peritoneum. The homeostasis of other macrophage populations and monocytes is unaffected, but monocytes and their progenitors in bone marrow lack surface CSF1R. Finally, Csf1r mice are healthy and fertile without the growth, neurological or developmental abnormalities reported in Csf1r rodents. Csf1r mice thus provide a model to explore the homeostatic, physiological and immunological functions of tissue-specific macrophage populations in adult animals

The development and maintenance of the mononuclear phagocyte system of the chick is controlled by signals from the macrophage colony-stimulating factor (CSF1) receptor

BACKGROUND: Macrophages have many functions in development and homeostasis as well as innate immunity. Recent studies in mammals suggest that cells arising in the yolk sac give rise to self-renewing macrophage populations that persist in adult tissues. Macrophage proliferation and differentiation is controlled by macrophage colony-stimulating factor (CSF1) and interleukin 34 (IL34), both agonists of the CSF1 receptor (CSF1R). In the current manuscript we describe the origin, function and regulation of macrophages, and the role of CSF1R signaling during embryonic development, using the chick as a model. RESULTS: Based upon RNA-sequencing comparison to bone marrow-derived macrophages grown in CSF1, we show that embryonic macrophages contribute around 2% of the total embryo RNA in day 7 chick embryos, and have similar gene expression profiles to bone marrow-derived macrophages. To explore the origins of embryonic and adult macrophages, we injected Hamburger-Hamilton stage 16 to 17 chick embryos with either yolk sac-derived blood cells, or bone marrow cells from EGFP(+) donors. In both cases, the transferred cells gave rise to large numbers of EGFP(+) tissue macrophages in the embryo. In the case of the yolk sac, these cells were not retained in hatched birds. Conversely, bone marrow EGFP(+) cells gave rise to tissue macrophages in all organs of adult birds, and regenerated CSF1-responsive marrow macrophage progenitors. Surprisingly, they did not contribute to any other hematopoietic lineage. To explore the role of CSF1 further, we injected embryonic or hatchling CSF1R-reporter transgenic birds with a novel chicken CSF1-Fc conjugate. In both cases, the treatment produced a large increase in macrophage numbers in all tissues examined. There were no apparent adverse effects of chicken CSF1-Fc on embryonic or post-hatch development, but there was an unexpected increase in bone density in the treated hatchlings. CONCLUSIONS: The data indicate that the yolk sac is not the major source of macrophages in adult birds, and that there is a macrophage-restricted, self-renewing progenitor cell in bone marrow. CSF1R is demonstrated to be limiting for macrophage development during development in ovo and post-hatch. The chicken provides a novel and tractable model to study the development of the mononuclear phagocyte system and CSF1R signaling. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12915-015-0121-9) contains supplementary material, which is available to authorized users

Macrophage biology in development, homeostasis and disease

Macrophages the most plastic cells of the hematopoietic system are found in all tissues and exhibit great functional diversity. They have roles in development, homeostasis, tissue repair, and immunity. While anatomically distinct, resident tissue macrophages exhibit different transcriptional profiles, and functional capabilities, they are all required for the maintenance of homeostasis. However, these reparative and homeostatic functions can be subverted by chronic insults, resulting in a causal association of macrophages with disease states. In this review, we discuss how macrophages regulate normal physiology and development and provide several examples of their pathophysiologic roles in disease. We define the “hallmarks” of macrophages performing particular functions, taking into account novel insights into the diversity of their lineages, identity, and regulation. This diversity is essential to understand because macrophages have emerged as important therapeutic targets in many important human diseases

Advancing liquid biopsy for minimal residual disease tracking in diffuse large B-cell lymphoma

Diffuse Large B-Cell Lymphoma (DLBCL) is a curable malignant haematological disorder. With the recent expansion in therapeutic option, the need for precise disease monitoring is rising. In this research thesis, our primary objective was to enhance minimal residual disease monitoring by exploring two avenues: the potential of extracellular vesicles (EVs) as novel biomarkers and the adaptation of nanopore sequencing for cell-free DNA (cfDNA) To study this, we set up a biomarker study to prospectively collect samples from patients with high grade B-cell lymphoma. We sampled patients prior to treatment, at each chemotherapy cycle and during remission monitoring. We systematically examined extracellular vesicle (EV) DNA and assessed B-cell markers using a novel nano flow-cytometry method. Next, we assessed cfDNA profiles in plasma, designed a targeted sequencing panel and used ultra-deep sequencing to study clonal dynamics over time for all patients. In the last phase, we tested nanopore sequencing on cfDNA from a smaller subset of patients. We optimised library preparation and flow cell loading for nanopore and developed different data analysis workflows for Illumina and Nanopore data. We collected nearly 100 samples from 22 patients over two years. We confirmed a clear difference in cell-free DNA plasma concentrations between patients and healthy persons. CfDNA concentrations in plasma generally mirror tumour bulk and the response to treatment. Moreover, we established the predictive power of cfDNA concentrations after a single cycle R-CHOP chemotherapy cycles on overall survival and examined the clinical application of clonal tracking and highlight potential implications for routine practice. We confirmed the viability of nanopore sequencing for cfDNA and with our modifications, we improved flow cell data outputs tenfold. Subsequently, we applied nanopore sequencing to characterise copy number alterations (CNA), hydroxymethylation and small nucleotide variants (SNV) in a subset of patients. However, our EV research concluded that EVs only contain negligible amounts of DNA, unlikely useful for liquid biopsy. And, in contrast to other authors, we did not find any relevant presence of B-cell markers on small DLBCL EVs. In conclusion, this thesis provides a multi-dimensional perspective on liquid biopsies for DLBCL, highlighting both challenges and opportunities, paving the way for subsequent research in this domain