PPAR is known for its anti-inflammatory actions in macrophages. However, which macrophage populations express PPAR in vivo and how it regulates tissue homeostasis in the steady state and during inflammation is not completely understood. We show that lung and spleen macrophages constitutively expressed PPAR, while other macrophage populations did not. Recruitment of monocytes to sites of inflammation was associated with induction of PPAR as they differentiated to macrophages. Its absence in these macrophages led to failed resolution of inflammation, characterized by persistent, low-level recruitment of leukocytes. Conversely, PPAR agonists supported an earlier cessation in leukocyte recruitment during resolution of acute inflammation and likewise suppressed monocyte recruitment to chronically inflamed atherosclerotic vessels. In the steady state, PPAR deficiency in macrophages had no obvious impact in the spleen but profoundly altered cellular lipid homeostasis in lung macrophages. Reminiscent of pulmonary alveolar proteinosis, LysM-Cre x PPARflox/flox mice displayed mild leukocytic inflammation in the steady-state lung and succumbed faster to mortality upon infection with S. pneumoniae. Surprisingly, this mortality was not due to overly exuberant inflammation, but instead to impaired bacterial clearance. Thus, in addition to its anti-inflammatory role in promoting resolution of inflammation, PPAR sustains functionality in lung macrophages and thereby has a pivotal role in supporting pulmonary host defense.
Systemic analysis of PPARγ in mouse macrophage populations reveals marked diversity in expression with critical roles in resolution of inflammation and airway immunity.
Sex, Treatment
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Progression of human bronchioloalveolar carcinoma to invasive adenocarcinoma is modeled in a transgenic mouse model of K-ras-induced lung cancer by loss of the TGF-β type II receptor.
Sex, Specimen part
View SamplesWe used an integrated computational/experimental systems biology approach to identify upstream protein kinases that regulate gene expression changes in kidneys of HIV-1 transgenic mice (Tg26), which have significant tubulo-interstitial fibrosis (TIF) and glomerulosclerosis (GS). We identified the homeo-domain interacting protein kinase 2 (HIPK2) as a key regulator of TIF and GS. HIPK2 was upregulated in kidneys of Tg26 and patients with various kidney diseases. HIV infection increased the protein level of HIPK2 by promoting oxidative stress, which inhibited Siah1-mediated proteasomal degradation of HIPK2.
No associated publication
Sex, Specimen part, Cell line
View SamplesRecent data suggests that repression of the Type II TGF-B Receptor (Tgfr2) repression in human lung adenocarcinoma is important for progression from noninvasive to invasive adenocarcinoma. To test this hypothesis in a animal model of non-invasive lung cancer, we generated an inducible, lung specific Tgfbr2 knockout model in the oncogenic Kras mouse.
Progression of human bronchioloalveolar carcinoma to invasive adenocarcinoma is modeled in a transgenic mouse model of K-ras-induced lung cancer by loss of the TGF-β type II receptor.
Specimen part
View SamplesRecent data suggests that repression of the Type II TGF-B Receptor (Tgfr2) repression in human lung adenocarcinoma is important for progression from noninvasive to invasive adenocarcinoma. To test this hypothesis in a animal model of non-invasive lung cancer, we generated an inducible, lung specific Tgfbr2 knockout model in the oncogenic Kras mouse.
No associated publication
Specimen part
View SamplesHuman and mouse blood each contain two monocyte subsets. Here, we investigated the extent of their similarity using a microarray approach. Approximately 300 genes in human and 550 genes in mouse were differentially expressed between subsets. More than 130 of these gene expression differences were conserved between mouse and human monocyte subsets. We confirmed numerous differences at the cell surface protein level. Despite overall conservation, some molecules were conversely expressed between the two species subsets, including CD36, CD9, and TREM-1. Furthermore, other differences existed, including a prominent PPAR signature in mouse monocytes absent in human. Overall, human and mouse monocyte subsets are far more broadly conserved than currently recognized. Thus, studies in mice may indeed yield relevant information regarding the biology of human monocyte subsets. However, differences between the species deserve consideration in models of human disease studied in the mouse.
Comparison of gene expression profiles between human and mouse monocyte subsets.
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View SamplesZfp281 is a partner protein of Nanog. To identify potential target genes of Zfp281, we generated Zfp281 null ESCs using gene targeting, and compared transcriptomic changes between multiple lines of wildtype, heterozygous and null ESCs.
No associated publication
Specimen part
View SamplesIL-10 production by Th17 cells is critical for limiting autoimmunity and inflammatory responses. Gene array analysis on Stat6 and T-bet double deficient Th17 cells identified the Th2 transcription factor c-Maf to be synergistically up-regulated by IL-6 plus TGFbeta, and associated with Th17 IL-10 production. Both c-Maf and IL-10 induction during Th17 polarization depended on Stat3, but not Stat6 or Stat1, and mechanistically differed from IL-10 regulation by Th2 or IL-27 signals. TGFbeta was also synergistic with IL-27 to induce c-Maf, and induced Stat1 independent IL-10 expression in contrast to IL-27 alone. Retroviral transduction of c-Maf was able to induce IL-10 expression in Stat6 deficient CD4 and CD8 T cells, and c-Maf directly transactivated IL-10 gene expression through binding to a MARE motif in the IL-10 promoter. Together, these data reveal a novel role for c-Maf in regulating T effector development, and suggest that TGFbeta may antagonize Th17 immunity by IL-10 production through c-Maf induction.
No associated publication
Sex, Specimen part
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Polycomb repressive complex 2 (PRC2) silences genes responsible for neurodegeneration.
Age, Specimen part
View SamplesCocaine-mediated repression of the histone methyltransferase (HMT) G9a has recently been implicated in transcriptional, morphological, and behavioral responses to chronic cocaine administration. Here, using a ribosomal affinity purification approach, we find that G9a repression by cocaine occurs in both Drd1 (striatonigral)- and Drd2 (striatopallidal)-expressing medium spiny neurons (MSNs). Conditional knockout and overexpression of G9a within these distinct cell types, however, reveals divergent behavioral phenotypes in response to repeated cocaine treatment. Our studies further indicate that such developmental deletion of G9a selectively in Drd2 neurons results in the unsilencing of transcriptional programs normally specific to striatonigral neurons, and the acquisition of Drd1-associated projection and electrophysiological properties. This partial striatopallidal to striatonigral switching phenotype in mice indicates a novel role for G9a in contributing to neuronal subtype identity, and suggests a critical function for cell-type specific histone methylation patterns in the regulation of behavioral responses to environmental stimuli.
G9a influences neuronal subtype specification in striatum.
Sex, Specimen part
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