@article {49538, title = {The generation of macrophages with anti-inflammatory activity in the absence of STAT6 signaling.}, volume = {98}, year = {2015}, month = {2015 Sep}, pages = {395-407}, abstract = {

Macrophages readily change their phenotype in response to exogenous stimuli. In this work, macrophages were stimulated under a variety of experimental conditions, and phenotypic alterations were correlated with changes in gene expression. We identified 3 transcriptionally related populations of macrophages with immunoregulatory activity. They were generated by stimulating cells with TLR ligands in the presence of 3 different "reprogramming" signals: high-density ICs, PGE2, or Ado. All 3 of these cell populations produced high levels of transcripts for IL-10 and growth and angiogenic factors. They also secreted reduced levels of inflammatory cytokines IL-1β, IL-6, and IL-12. All 3 macrophage phenotypes could partially rescue mice from lethal endotoxemia, and therefore, we consider each to have anti-inflammatory activity. This ability to regulate innate-immune responses occurred equally well in macrophages from STAT6-deficient mice. The lack of STAT6 did not affect the ability of macrophages to change cytokine production reciprocally or to rescue mice from lethal endotoxemia. Furthermore, treatment of macrophages with IL-4 failed to induce similar phenotypic or transcriptional alterations. This work demonstrates that there are multiple ways to generate macrophages with immunoregulatory activity. These anti-inflammatory macrophages are transcriptionally and functionally related to each other and are quite distinct from macrophages treated with IL-4.

}, issn = {1938-3673}, doi = {10.1189/jlb.2A1114-560R}, author = {Fleming, Bryan D and Chandrasekaran, Prabha and Dillon, Laura A L and Dalby, Elizabeth and Suresh, Rahul and Sarkar, Arup and El-Sayed, Najib M and Mosser, David M} } @article {49796, title = {Simultaneous transcriptional profiling of Leishmania major and its murine macrophage host cell reveals insights into host-pathogen interactions.}, journal = {BMC Genomics}, volume = {16}, year = {2015}, month = {2015}, pages = {1108}, abstract = {

BACKGROUND: Parasites of the genus Leishmania are the causative agents of leishmaniasis, a group of diseases that range in manifestations from skin lesions to fatal visceral disease. The life cycle of Leishmania parasites is split between its insect vector and its mammalian host, where it resides primarily inside of macrophages. Once intracellular, Leishmania parasites must evade or deactivate the host{\textquoteright}s innate and adaptive immune responses in order to survive and replicate.

RESULTS: We performed transcriptome profiling using RNA-seq to simultaneously identify global changes in murine macrophage and L. major gene expression as the parasite entered and persisted within murine macrophages during the first 72 h of an infection. Differential gene expression, pathway, and gene ontology analyses enabled us to identify modulations in host and parasite responses during an infection. The most substantial and dynamic gene expression responses by both macrophage and parasite were observed during early infection. Murine genes related to both pro- and anti-inflammatory immune responses and glycolysis were substantially upregulated and genes related to lipid metabolism, biogenesis, and Fc gamma receptor-mediated phagocytosis were downregulated. Upregulated parasite genes included those aimed at mitigating the effects of an oxidative response by the host immune system while downregulated genes were related to translation, cell signaling, fatty acid biosynthesis, and flagellum structure.

CONCLUSIONS: The gene expression patterns identified in this work yield signatures that characterize multiple developmental stages of L. major parasites and the coordinated response of Leishmania-infected macrophages in the real-time setting of a dual biological system. This comprehensive dataset offers a clearer and more sensitive picture of the interplay between host and parasite during intracellular infection, providing additional insights into how pathogens are able to evade host defenses and modulate the biological functions of the cell in order to survive in the mammalian environment.

}, issn = {1471-2164}, doi = {10.1186/s12864-015-2237-2}, author = {Dillon, Laura A L and Suresh, Rahul and Okrah, Kwame and Corrada Bravo, Hector and Mosser, David M and El-Sayed, Najib M} } @article {49539, title = {Transcriptomic profiling of gene expression and RNA processing during Leishmania major differentiation.}, volume = {43}, year = {2015}, month = {2015 Aug 18}, pages = {6799-813}, abstract = {

Protozoan parasites of the genus Leishmania are the etiological agents of leishmaniasis, a group of diseases with a worldwide incidence of 0.9-1.6 million cases per year. We used RNA-seq to conduct a high-resolution transcriptomic analysis of the global changes in gene expression and RNA processing events that occur as L. major transforms from non-infective procyclic promastigotes to infective metacyclic promastigotes. Careful statistical analysis across multiple biological replicates and the removal of batch effects provided a high quality framework for comprehensively analyzing differential gene expression and transcriptome remodeling in this pathogen as it acquires its infectivity. We also identified precise 5{\textquoteright} and 3{\textquoteright} UTR boundaries for a majority of Leishmania genes and detected widespread alternative trans-splicing and polyadenylation. An investigation of possible correlations between stage-specific preferential trans-splicing or polyadenylation sites and differentially expressed genes revealed a lack of systematic association, establishing that differences in expression levels cannot be attributed to stage-regulated alternative RNA processing. Our findings build on and improve existing expression datasets and provide a substantially more detailed view of L. major biology that will inform the field and potentially provide a stronger basis for drug discovery and vaccine development efforts.

}, issn = {1362-4962}, doi = {10.1093/nar/gkv656}, author = {Dillon, Laura A L and Okrah, Kwame and Hughitt, V Keith and Suresh, Rahul and Li, Yuan and Fernandes, Maria Cecilia and Belew, A Trey and Corrada Bravo, Hector and Mosser, David M and El-Sayed, Najib M} }