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 PPARĪ³ in mouse macrophage populations reveals marked diversity in expression with critical roles in resolution of inflammation and airway immunity.
Sex, Treatment
View SamplesDown syndrome is the most common form of genetic mental retardation. How Trisomy 21 causes mental retardation remains unclear and its effects on adult neurogenesis have not been addressed. To gain insight into the mechanisms causing mental retardation we used microarrays to investigate gene expression differences between Ts1Cje (a mouse model of Down syndrome) and C57BL/6 littermate control neurospheres. The neurospheres were generated from neural stem cells and progenitors isolated from the lateral walls of the lateral ventricles from adult mice.
Gene network disruptions and neurogenesis defects in the adult Ts1Cje mouse model of Down syndrome.
Sex, Disease
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Age- and pregnancy-associated DNA methylation changes in mammary epithelial cells.
Sex, Age, Specimen part
View SamplesWnt signaling is intrinsic to mouse embryonic stem cell self-renewal. Therefore it is surprising that reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) is not strongly enhanced by Wnt signaling. Here, we demonstrate that active Wnt signaling inhibits the early stage of reprogramming to iPSCs, while it is required and even stimulating during the late stage. Mechanistically, this biphasic effect of Wnt signaling is accompanied by a change in the requirement of all four of its transcriptional effectors: Tcf1, Lef1, Tcf3, and Tcf4. For example, Tcf3 and Tcf4 are stimulatory early but inhibitory late in the reprogramming process. Accordingly, ectopic expression of Tcf3 early in reprogramming combined with its loss-of-function late enables efficient reprogramming in the absence of ectopic Sox2. Together, our data indicate that the step-wise process of reprogramming to iPSCs is critically dependent on the stage-specific control and action of all four Tcfs and Wnt signaling.
Stage-specific regulation of reprogramming to induced pluripotent stem cells by Wnt signaling and T cell factor proteins.
Specimen part, Time
View SamplesEpithelial Hedgehog (Hh) ligands regulate several aspects of fetal intestinal organogenesis and emerging data implicate the Hh pathway in inflammatory signaling in adult colon. We investigated the effects of chronic Hh inhibition in vivo and profiled molecular pathways acutely modulated by Hh signaling in the intestinal mesenchyme.
Hedgehog is an anti-inflammatory epithelial signal for the intestinal lamina propria.
Specimen part
View SamplesThe E-protein transcription factors E2A and HEB play important roles at several stages of hematopoiesis. However, the exact mechanism for theire action and the main targets in the LY6D negative common lymphoid progentior (CLP) compartment remains unknown. By adressing this question, we will gain important infromation regarding the early events leading to B-cell specification.
The transcription factors E2A and HEB act in concert to induce the expression of FOXO1 in the common lymphoid progenitor.
Specimen part
View SamplesMetabolically active cells require robust mechanisms to combat oxidative stress. The cytoplasmic thioredoxin reductase/thioredoxin (Txnrd1/Txn1) system maintains reduced protein dithiols and provides electrons to some cellular reductases, including peroxiredoxins.
Cytoprotective Nrf2 pathway is induced in chronically txnrd 1-deficient hepatocytes.
Specimen part
View Samples[1] Lactic acidosis time course: MCF7 cells were exposed to lactic acidosis for different length of time. We used microarrays to examine the genomic programs of cells incubated under lactic acidosis for different length of time
Lactic acidosis triggers starvation response with paradoxical induction of TXNIP through MondoA.
Cell line, Treatment
View SamplesAlthough Notch signaling has been clearly implicated in lymphoid differentiation, its role in myeloid lineages differentiation is unclear.
Notch signaling specifies megakaryocyte development from hematopoietic stem cells.
No sample metadata fields
View SamplesRecent studies have documented genome-wide binding patterns of transcriptional regulators and their associated epigenetic marks in hematopoietic cell lineages. In order to determine how epigenetic marks are established and maintained during developmental progression, we have generated long-term cultures of hematopoietic progenitors by enforcing the expression of the E-protein antagonist Id2. Hematopoietic progenitors that express Id2 are multipotent and readily differentiate upon withdrawal of Id2 expression into committed B lineage cells, thus indicating a causative role for E2A (Tcf3) in promoting the B cell fate. Genome-wide analyses revealed that a substantial fraction of lymphoid and myeloid enhancers are premarked by the poised or active enhancer mark H3K4me1 in multipotent progenitors. Thus, in hematopoietic progenitors, multilineage priming of enhancer elements precedes commitment to the lymphoid or myeloid cell lineages.
Multilineage priming of enhancer repertoires precedes commitment to the B and myeloid cell lineages in hematopoietic progenitors.
Specimen part
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