Publications by authors named "Lucas Lefevre"

17 Publications

  • Page 1 of 1

CRISPR-Cas9 Editing of Human Histone Deubiquitinase Gene in Human Monocytic Leukemia Cell Line THP-1.

Front Cell Dev Biol 2021 31;9:679544. Epub 2021 May 31.

The Roslin Institute, University of Edinburgh, Easter Bush, United Kingdom.

USP16 is a histone deubiquitinase which facilitates G2/M transition during the cell cycle, regulates DNA damage repair and contributes to inducible gene expression. We mutated the gene in a high differentiation clone of the acute monocytic leukemia cell line THP-1 using the CRISPR-Cas9 system and generated four homozygous knockout clones. All were able to proliferate and to differentiate in response to phorbol ester (PMA) treatment. One line was highly proliferative prior to PMA treatment and shut down proliferation upon differentiation, like wild type. Three clones showed sustained expression of the progenitor cell marker , indicating that differentiation had not completely blocked proliferation in these clones. Network analysis of transcriptomic differences among wild type, heterozygotes and homozygotes showed clusters of genes that were up- or down-regulated after differentiation in all cell lines. Prior to PMA treatment, the homozygous clones had lower levels than wild type of genes relating to metabolism and mitochondria, including , encoding an interaction partner of USP16. There was also apparent loss of interferon signaling. In contrast, a number of genes were up-regulated in the homozygous cells compared to wild type at baseline, including other deubiquitinases (, and ). However, three homozygotes failed to fully induce during differentiation. Other network clusters showed effects prior to or after differentiation in the homozygous clones. Thus the removal of USP16 affected the transcriptome of the cells, although all these lines were able to survive, which suggests that the functions attributed to USP16 may be redundant. Our analysis indicates that the leukemic line can adapt to the extreme selection pressure applied by the loss of USP16, and the harsh conditions of the gene editing and selection protocol, through different compensatory pathways. Similar selection pressures occur during the evolution of a cancer , and our results can be seen as a case study in leukemic cell adaptation. USP16 has been considered a target for cancer chemotherapy, but our results suggest that treatment would select for escape mutants that are resistant to USP16 inhibitors.
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http://dx.doi.org/10.3389/fcell.2021.679544DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8203323PMC
May 2021

Transcriptomic Analysis of Rat Macrophages.

Front Immunol 2020 1;11:594594. Epub 2021 Feb 1.

Mater Research Institute Mater Research Institute - University of Queensland, Brisbane, QLD, Australia.

The laboratory rat is widely used as a model for human diseases. Many of these diseases involve monocytes and tissue macrophages in different states of activation. Whilst methods for differentiation of mouse macrophages from embryonic stem cells (ESC) and bone marrow (BM) are well established, these are lacking for the rat. The gene expression profiles of rat macrophages have also not been characterised to the same extent as mouse. We have established the methodology for production of rat ESC-derived macrophages and compared their gene expression profiles to macrophages obtained from the lung and peritoneal cavity and those differentiated from BM and blood monocytes. We determined the gene signature of Kupffer cells in the liver using rats deficient in macrophage colony stimulating factor receptor (CSF1R). We also examined the response of BM-derived macrophages to lipopolysaccharide (LPS). The results indicate that many, but not all, tissue-specific adaptations observed in mice are conserved in the rat. Importantly, we show that unlike mice, rat macrophages express the CSF1R ligand, colony stimulating factor 1 (CSF1).
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http://dx.doi.org/10.3389/fimmu.2020.594594DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7902030PMC
June 2021

Use of quantitative real-time PCR to determine the local inflammatory response in the intestinal mucosa and muscularis of horses undergoing small intestinal resection.

Equine Vet J 2021 Feb 1. Epub 2021 Feb 1.

The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, UK.

Background: Studies in rodents and humans have demonstrated that intestinal manipulation or surgical trauma initiates an inflammatory response in the intestine which results in leucocyte recruitment to the muscularis externa causing smooth muscle dysfunction.

Objectives: To examine the intestinal inflammatory response in horses undergoing colic surgery by measuring relative differential gene expression in intestinal tissues harvested from surgical colic cases and control horses.

Study Design: Prospective case-control study.

Methods: Mucosa and muscularis externa were harvested from healthy margins of resected small intestine from horses undergoing colic surgery (n = 12) and from intestine derived from control horses euthanised for reasons unrelated to the gastrointestinal tract (n = 6). Tissue was analysed for genes encoding proteins involved in the inflammatory response: interleukin (IL) 6 and IL1β, C-C motif chemokine ligand 2 (CCL2), tumour necrosis factor (TNF), prostaglandin-endoperoxide synthase 2 (PTGS2) and indoleamine 2,3-dioxygenase (IDO1). Relative expression of these genes was compared between the two groups. Further analysis was applied to the colic cases to determine whether the magnitude of relative gene expression was associated with the subsequent development of post-operative reflux (POR).

Results: Samples obtained from colic cases had increased relative expression of IL1β, IL6, CCL2 and TNF in the mucosa and muscularis externa when compared with the control group. There was no difference in relative gene expression between proximal and distal resection margins and no association between duration of colic, age, resection length, short-term survival and the presence of pre-operative reflux and the relative expression of the genes of interest. Horses that developed POR had significantly greater relative gene expression of TNF in the mucosa compared with horses that did not develop POR.

Main Limitations: Small sample size per group and variation within the colic cases.

Conclusions: These preliminary data support an upregulation of inflammatory genes in the intestine of horses undergoing colic surgery.
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http://dx.doi.org/10.1111/evj.13429DOI Listing
February 2021

The Transcriptional Network That Controls Growth Arrest and Macrophage Differentiation in the Human Myeloid Leukemia Cell Line THP-1.

Front Cell Dev Biol 2020 3;8:498. Epub 2020 Jul 3.

The Roslin Institute, The University of Edinburgh, Edinburgh, United Kingdom.

The response of the human acute myeloid leukemia cell line THP-1 to phorbol esters has been widely studied to test candidate leukemia therapies and as a model of cell cycle arrest and monocyte-macrophage differentiation. Here we have employed Cap Analysis of Gene Expression (CAGE) to analyze a dense time course of transcriptional regulation in THP-1 cells treated with phorbol myristate acetate (PMA) over 96 h. PMA treatment greatly reduced the numbers of cells entering S phase and also blocked cells exiting G2/M. The PMA-treated cells became adherent and expression of mature macrophage-specific genes increased progressively over the duration of the time course. Within 1-2 h PMA induced known targets of tumor protein p53 (TP53), notably , followed by gradual down-regulation of cell-cycle associated genes. Also within the first 2 h, PMA induced immediate early genes including transcription factor genes encoding proteins implicated in macrophage differentiation () and down-regulated genes for transcription factors involved in immature myeloid cell proliferation (). The dense time course revealed that the response to PMA was not linear and progressive. Rather, network-based clustering of the time course data highlighted a sequential cascade of transient up- and down-regulated expression of genes encoding feedback regulators, as well as transcription factors associated with macrophage differentiation and their inferred target genes. CAGE also identified known and candidate novel enhancers expressed in THP-1 cells and many novel inducible genes that currently lack functional annotation and/or had no previously known function in macrophages. The time course is available on the ZENBU platform allowing comparison to FANTOM4 and FANTOM5 data.
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http://dx.doi.org/10.3389/fcell.2020.00498DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7347797PMC
July 2020

A Gene Expression Atlas of the Domestic Water Buffalo ().

Front Genet 2019 24;10:668. Epub 2019 Jul 24.

Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, QLD, Australia.

The domestic water buffalo () makes a major contribution to the global agricultural economy in the form of milk, meat, hides, and draught power. The global water buffalo population is predominantly found in Asia, and per head of population more people depend upon the buffalo than on any other livestock species. Despite its agricultural importance, there are comparatively fewer genomic and transcriptomic resources available for buffalo than for other livestock species. We have generated a large-scale gene expression atlas covering multiple tissue and cell types from all major organ systems collected from three breeds of riverine water buffalo (Mediterranean, Pandharpuri and Bhadawari) and used the network analysis tool Graphia Professional to identify clusters of genes with similar expression profiles. Alongside similar data, we and others have generated for ruminants as part of the Functional Annotation of Animal Genomes Consortium; this comprehensive transcriptome supports functional annotation and comparative analysis of the water buffalo genome.
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http://dx.doi.org/10.3389/fgene.2019.00668DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6689995PMC
July 2019

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

Nat Commun 2019 07 19;10(1):3215. Epub 2019 Jul 19.

University of Edinburgh Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh BioQuarter, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK.

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.
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http://dx.doi.org/10.1038/s41467-019-11053-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6642117PMC
July 2019

Chromosome-level assembly of the water buffalo genome surpasses human and goat genomes in sequence contiguity.

Nat Commun 2019 01 16;10(1):260. Epub 2019 Jan 16.

The Davies Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA, 5371, Australia.

Rapid innovation in sequencing technologies and improvement in assembly algorithms have enabled the creation of highly contiguous mammalian genomes. Here we report a chromosome-level assembly of the water buffalo (Bubalus bubalis) genome using single-molecule sequencing and chromatin conformation capture data. PacBio Sequel reads, with a mean length of 11.5 kb, helped to resolve repetitive elements and generate sequence contiguity. All five B. bubalis sub-metacentric chromosomes were correctly scaffolded with centromeres spanned. Although the index animal was partly inbred, 58% of the genome was haplotype-phased by FALCON-Unzip. This new reference genome improves the contig N50 of the previous short-read based buffalo assembly more than a thousand-fold and contains only 383 gaps. It surpasses the human and goat references in sequence contiguity and facilitates the annotation of hard to assemble gene clusters such as the major histocompatibility complex (MHC).
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http://dx.doi.org/10.1038/s41467-018-08260-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6335429PMC
January 2019

Species-Specific Transcriptional Regulation of Genes Involved in Nitric Oxide Production and Arginine Metabolism in Macrophages.

Immunohorizons 2018 Jan;2(1):27-37

The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, United Kingdom.

Activated mouse macrophages metabolize arginine via NO synthase (NOS2) to produce NO as an antimicrobial effector. Published gene expression datasets provide little support for the activation of this pathway in human macrophages. Generation of NO requires the coordinated regulation of multiple genes. We have generated RNA-sequencing data from bone marrow-derived macrophages from representative rodent (rat), monogastric (pig and horse), and ruminant (sheep, goat, cattle, and water buffalo) species, and analyzed the expression of genes involved in arginine metabolism in response to stimulation with LPS. In rats, as in mice, LPS strongly induced , the arginine transporter , arginase 1 (), GTP cyclohydrolase (), and argininosuccinate synthase (). None of these responses was conserved across species. Only cattle and water buffalo showed substantial induction. The species studied also differed in expression and regulation of arginase (, rather than ), and amino acid transporters. Variation between species was associated with rapid promoter evolution. Differential induction of and between the ruminant species was associated with insertions of the Bov-A2 retrotransposon in the promoter region. Bov-A2 was shown to possess LPS-inducible enhancer activity in transfected RAW264.7 macrophages. Consistent with a function in innate immunity, NO production and arginine metabolism vary greatly between species and differences may contribute to pathogen host restriction.
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http://dx.doi.org/10.4049/immunohorizons.1700073DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6245571PMC
January 2018

ADGRE1 (EMR1, F4/80) Is a Rapidly-Evolving Gene Expressed in Mammalian Monocyte-Macrophages.

Front Immunol 2018 1;9:2246. Epub 2018 Oct 1.

Mater Research-University of Queensland, Woolloongabba, QLD, Australia.

The F4/80 antigen, encoded by the locus, has been widely-used as a monocyte-macrophage marker in mice, but its value as a macrophage marker in other species is unclear, and has even been questioned. ADGRE1 is a seven transmembrane G protein-coupled receptor with an extracellular domain containing repeated Epidermal Growth Factor (EGF)-like calcium binding domains. Using a new monoclonal antibody, we demonstrated that ADGRE1 is a myeloid differentiation marker in pigs, absent from progenitors in bone marrow, highly-expressed in mature granulocytes, monocytes, and tissue macrophages and induced by macrophage colony-stimulating factor (CSF1) treatment . Based upon these observations, we utilized RNA-Seq to assess the expression of mRNA in bone marrow or monocyte-derived macrophages (MDM) and alveolar macrophages from 8 mammalian species including pig, human, rat, sheep, goat, cow, water buffalo, and horse. mRNA was expressed by macrophages in each species, with inter-species variation both in expression level and response to lipopolysaccharide (LPS) stimulation. Analysis of the RNA-Seq data also revealed additional exons in several species compared to current Ensembl annotations. The ruminant species and horses appear to encode a complete duplication of the 7 EGF-like domains. In every species, Sashimi plots revealed evidence of exon skipping of the EGF-like domains, which are highly-variable between species and polymorphic in humans. Consistent with these expression patterns, key elements of the promoter and a putative enhancer are also conserved across all species. The rapid evolution of this molecule and related ADGRE family members suggests immune selection and a role in pathogen recognition.
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http://dx.doi.org/10.3389/fimmu.2018.02246DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6174849PMC
October 2019

Pleiotropic Impacts of Macrophage and Microglial Deficiency on Development in Rats with Targeted Mutation of the Locus.

J Immunol 2018 11 24;201(9):2683-2699. Epub 2018 Sep 24.

The University of Edinburgh Centre for Inflammation Research, The Queen's Medical Research Institute, Edinburgh EH16 4TJ, United Kingdom;

We have produced -deficient rats by homologous recombination in embryonic stem cells. Consistent with the role of in macrophage differentiation, there was a loss of peripheral blood monocytes, microglia in the brain, epidermal Langerhans cells, splenic marginal zone macrophages, bone-associated macrophages and osteoclasts, and peritoneal macrophages. Macrophages of splenic red pulp, liver, lung, and gut were less affected. The pleiotropic impacts of the loss of macrophages on development of multiple organ systems in rats were distinct from those reported in mice. rats survived well into adulthood with postnatal growth retardation, distinct skeletal and bone marrow abnormalities, infertility, and loss of visceral adipose tissue. Gene expression analysis in spleen revealed selective loss of transcripts associated with the marginal zone and, in brain regions, the loss of known and candidate novel microglia-associated transcripts. Despite the complete absence of microglia, there was little overt phenotype in brain, aside from reduced myelination and increased expression of dopamine receptor-associated transcripts in striatum. The results highlight the redundant and nonredundant functions of CSF1R signaling and of macrophages in development, organogenesis, and homeostasis.
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http://dx.doi.org/10.4049/jimmunol.1701783DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6196293PMC
November 2018

Macrophage colony-stimulating factor increases hepatic macrophage content, liver growth, and lipid accumulation in neonatal rats.

Am J Physiol Gastrointest Liver Physiol 2018 03 21;314(3):G388-G398. Epub 2017 Dec 21.

The Roslin Institute, University of Edinburgh , Edinburgh , United Kingdom.

Signaling via the colony-stimulating factor 1 receptor (CSF1R) controls the survival, differentiation, and proliferation of macrophages. Mutations in CSF1 or CSF1R in mice and rats have pleiotropic effects on postnatal somatic growth. We tested the possible application of pig CSF1-Fc fusion protein as a therapy for low birth weight (LBW) at term, using a model based on maternal dexamethasone treatment in rats. Neonatal CSF1-Fc treatment did not alter somatic growth and did not increase the blood monocyte count. Instead, there was a substantial increase in the size of liver in both control and LBW rats, and the treatment greatly exacerbated lipid droplet accumulation seen in the dexamethasone LBW model. These effects were reversed upon cessation of treatment. Transcriptional profiling of the livers supported histochemical evidence of a large increase in macrophages with a resident Kupffer cell phenotype and revealed increased expression of many genes implicated in lipid droplet formation. There was no further increase in hepatocyte proliferation over the already high rates in neonatal liver. In conclusion, treatment of neonatal rats with CSF1-Fc caused an increase in liver size and hepatic lipid accumulation, due to Kupffer cell expansion and/or activation rather than hepatocyte proliferation. Increased liver macrophage numbers and expression of endocytic receptors could mitigate defective clearance functions in neonates. NEW & NOTEWORTHY This study is based on extensive studies in mice and pigs of the role of CSF1/CSF1R in macrophage development and postnatal growth. We extended the study to neonatal rats as a possible therapy for low birth weight. Unlike our previous studies in mice and pigs, there was no increase in hepatocyte proliferation and no increase in monocyte numbers. Instead, neonatal rats treated with CSF1 displayed reversible hepatic steatosis and Kupffer cell expansion.
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http://dx.doi.org/10.1152/ajpgi.00343.2017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5899243PMC
March 2018

A high resolution atlas of gene expression in the domestic sheep (Ovis aries).

PLoS Genet 2017 Sep 15;13(9):e1006997. Epub 2017 Sep 15.

The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, Scotland, United Kingdom.

Sheep are a key source of meat, milk and fibre for the global livestock sector, and an important biomedical model. Global analysis of gene expression across multiple tissues has aided genome annotation and supported functional annotation of mammalian genes. We present a large-scale RNA-Seq dataset representing all the major organ systems from adult sheep and from several juvenile, neonatal and prenatal developmental time points. The Ovis aries reference genome (Oar v3.1) includes 27,504 genes (20,921 protein coding), of which 25,350 (19,921 protein coding) had detectable expression in at least one tissue in the sheep gene expression atlas dataset. Network-based cluster analysis of this dataset grouped genes according to their expression pattern. The principle of 'guilt by association' was used to infer the function of uncharacterised genes from their co-expression with genes of known function. We describe the overall transcriptional signatures present in the sheep gene expression atlas and assign those signatures, where possible, to specific cell populations or pathways. The findings are related to innate immunity by focusing on clusters with an immune signature, and to the advantages of cross-breeding by examining the patterns of genes exhibiting the greatest expression differences between purebred and crossbred animals. This high-resolution gene expression atlas for sheep is, to our knowledge, the largest transcriptomic dataset from any livestock species to date. It provides a resource to improve the annotation of the current reference genome for sheep, presenting a model transcriptome for ruminants and insight into gene, cell and tissue function at multiple developmental stages.
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http://dx.doi.org/10.1371/journal.pgen.1006997DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5626511PMC
September 2017

Phenotypic and Molecular Alterations in the Mammary Tissue of R-Spondin1 Knock-Out Mice during Pregnancy.

PLoS One 2016 9;11(9):e0162566. Epub 2016 Sep 9.

GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France.

R-spondin1 (Rspo1) is a member of a secreted protein family which has pleiotropic functions in development and stem cell growth. Rspo1 knock-out mice are sex-reversed, but some remain sub-fertile, so they fail to nurse their pups. A lack of Rspo1 expression in the mammary gland results in an absence of duct side-branching development and defective alveolar formation. The aim of this study was to characterize the phenotypic and molecular alterations of mammary gland due to Rspo1 knock-out. Using the transcriptional profiling of mammary tissues, we identified misregulated genes in the mammary gland of Rspo1 knock-out mice during pregnancy. A stronger expression of mesenchymal markers was observed, without modifications to the structure of mammary epithelial tissue. Mammary epithelial cell immunohistochemical analysis revealed a persistence of virgin markers, which signify a delay in cell differentiation. Moreover, serial transplantation experiments showed that Rspo1 is associated with a regenerative potential of mammary epithelial cell control. Our finding also highlights the negatively regulated expression of Rspo1's partners, Lgr4 and RNF43, in the mammary gland during pregnancy. Moreover, we offer evidence that Tgf-β signalling is modified in the absence of Rspo1. Taken together, our results show an abrupt halt or delay to mammary development during pregnancy due to the loss of a further differentiated function.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0162566PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5017653PMC
August 2017

A Csf1r-EGFP Transgene Provides a Novel Marker for Monocyte Subsets in Sheep.

J Immunol 2016 09 12;197(6):2297-305. Epub 2016 Aug 12.

The Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, United Kingdom; and

Expression of Csf1r in adults is restricted to cells of the macrophage lineage. Transgenic reporters based upon the Csf1r locus require inclusion of the highly conserved Fms-intronic regulatory element for expression. We have created Csf1r-EGFP transgenic sheep via lentiviral transgenesis of a construct containing elements of the mouse Fms-intronic regulatory element and Csf1r promoter. Committed bone marrow macrophage precursors and blood monocytes express EGFP in these animals. Sheep monocytes were divided into three populations, similar to classical, intermediate, and nonclassical monocytes in humans, based upon CD14 and CD16 expression. All expressed EGFP, with increased levels in the nonclassical subset. Because Csf1r expression coincides with the earliest commitment to the macrophage lineage, Csf1r-EGFP bone marrow provides a tool for studying the earliest events in myelopoiesis using the sheep as a model.
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http://dx.doi.org/10.4049/jimmunol.1502336DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5009875PMC
September 2016

Macrophage colony-stimulating factor (CSF1) controls monocyte production and maturation and the steady-state size of the liver in pigs.

Am J Physiol Gastrointest Liver Physiol 2016 09 21;311(3):G533-47. Epub 2016 Jul 21.

The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Scotland, United Kingdom; and

Macrophage colony-stimulating factor (CSF1) is an essential growth and differentiation factor for cells of the macrophage lineage. To explore the role of CSF1 in steady-state control of monocyte production and differentiation and tissue repair, we previously developed a bioactive protein with a longer half-life in circulation by fusing pig CSF1 with the Fc region of pig IgG1a. CSF1-Fc administration to pigs expanded progenitor pools in the marrow and selectively increased monocyte numbers and their expression of the maturation marker CD163. There was a rapid increase in the size of the liver, and extensive proliferation of hepatocytes associated with increased macrophage infiltration. Despite the large influx of macrophages, there was no evidence of liver injury and no increase in circulating liver enzymes. Microarray expression profiling of livers identified increased expression of macrophage markers, i.e., cytokines such as TNF, IL1, and IL6 known to influence hepatocyte proliferation, alongside cell cycle genes. The analysis also revealed selective enrichment of genes associated with portal, as opposed to centrilobular regions, as seen in hepatic regeneration. Combined with earlier data from the mouse, this study supports the existence of a CSF1-dependent feedback loop, linking macrophages of the liver with bone marrow and blood monocytes, to mediate homeostatic control of the size of the liver. The results also provide evidence of safety and efficacy for possible clinical applications of CSF1-Fc.
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http://dx.doi.org/10.1152/ajpgi.00116.2016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5076001PMC
September 2016

Contribution of mammary epithelial cells to the immune response during early stages of a bacterial infection to Staphylococcus aureus.

Vet Res 2014 Feb 12;45:16. Epub 2014 Feb 12.

INRA, UMR1313 Unité Génétique Animale et Biologie Intégrative, équipe «Lait, Génome & Santé», F-78350 Jouy-en-Josas, France.

To differentiate between the contribution of mammary epithelial cells (MEC) and infiltrating immune cells to gene expression profiles of mammary tissue during early stage mastitis, we investigated in goats the in vivo transcriptional response of MEC to an experimental intra mammary infection (IMI) with Staphylococcus aureus, using a non-invasive RNA sampling method from milk fat globules (MFG). Microarrays were used to record gene expression patterns during the first 24 hours post-infection (hpi). This approach was combined with laser capture microdissection of MEC from frozen slides of mammary tissue to analyze some relevant genes at 30 hpi. During the early stages post-inoculation, MEC play an important role in the recruitment and activation of inflammatory cells through the IL-8 signalling pathway and initiate a sharp induction of innate immune genes predominantly associated with the pro-inflammatory response. At 30 hpi, MEC express genes encoding different acute phase proteins, including SAA3, SERPINA1 and PTX3 and factors, such as S100A12, that contribute directly to fighting the infection. No significant change in the expression of genes encoding caseins was observed until 24 hpi, thus validating our experimental model to study early stages of infection before the occurrence of tissue damage, since the milk synthesis function is still operative. This is to our knowledge the first report showing in vivo, in goats, how MEC orchestrate the innate immune response to an IMI challenge with S. aureus. Moreover, the non-invasive sampling method of mammary representative RNA from MFG provides a valuable tool to easily follow the dynamics of gene expression in MEC to search for sensitive biomarkers in milk for early detection of mastitis and therefore, to successfully improve the treatment and thus animal welfare.
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http://dx.doi.org/10.1186/1297-9716-45-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3937043PMC
February 2014
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