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
View SamplesDuring embryogenesis, many key transcription factors are used repeatedly, achieving different outcomes depending on cell type and developmental stage. The epigenetic modification of the genome functions as a memory of a cells developmental history, and it has been proposed that such modification shapes the cellular response to transcription factors. To investigate the role of DNA methylation in the response to transcription factor Gata4, we examined expression profiles of Dnmt3a-/-Dnmt3b-/- ES cell-derived mesoderm cells cultured for 4 days with or without Gata4 activation, as well as the wild-type counterparts, using Affymetrix microarrays.
DNA methylation restricts lineage-specific functions of transcription factor Gata4 during embryonic stem cell differentiation.
Specimen part
View SamplesGenome-wide comparative gene expression analysis of callus tissue of osteoporotic mice (Col1a1-Krm2 and Lrp5-/-) and wild-type were performed to identify candidate genes that might be responsible for the impaired fracture healing observed in Col1a1-Krm2 and Lrp5-/- mice.
Osteoblast-specific Krm2 overexpression and Lrp5 deficiency have different effects on fracture healing in mice.
Sex, Age, Specimen part
View Samplesprenatal stress response, genetic modification
Differential effects of prenatal stress in 5-Htt deficient mice: towards molecular mechanisms of gene × environment interactions.
Sex, Specimen part, Treatment
View SamplesFoxl2 is a forkhead transcription factor expressed only in the female, but not in the male gonad. We have created mice homozygous mutant for the Foxl2 gene (KO) as well as mice carrying a conditional mutant Foxl2 allele (floxed).
Somatic sex reprogramming of adult ovaries to testes by FOXL2 ablation.
Specimen part
View SamplesBalanced immune responses in airways of patients with asthma are crucial to succesful clearance of viral infection and proper asthma control.
Rhinovirus-induced epithelial RIG-I inflammasome suppresses antiviral immunity and promotes inflammation in asthma and COVID-19.
Subject, Time
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