Comprehensive analysis of TLR4-induced transcriptional responses in interleukin 4-primed mouse macrophages.

Interferon (IFN)gamma and interleukin (IL)-4 are central regulators of T helper 1 (Th1) and T helper 2 (Th2) immune responses, respectively. Both cytokines have a major impact on macrophage phenotypes: IFNgamma-priming and subsequent TLR4 activation induces so-called "classically activated" macrophages that are characterized by pronounced pro-inflammatory responses, whereas IL-4-treated macrophages, commonly called "alternatively activated", are known to develop enhanced capacity for endocytosis, antigen presentation and tissue repair and are generally considered anti-inflammatory. Considering IL-4 as priming rather than activating stimulus, we now compared the TLR4-dependent global gene activation program in IFNgamma- versus IL-4-pretreated mouse macrophages, which has rarely been studied so far.

Interleukin-4 induced interferon regulatory factor (Irf) 4 participates in the regulation of alternative macrophage priming.

Interleukin (IL)-4 is a central regulator of T helper 2 (Th2) immune responses, and also has a major impact on innate immune cells. This cytokine primes macrophages for immune responses to parasites and induces a distinct macrophage phenotype that may also promote tissue repair. IL-4 signaling in macrophages is primarily mediated by the transcription factor signal transducer and activator of transcription 6 (Stat6), which in turn regulates a number of secondary DNA binding proteins that may participate in shaping the resulting phenotype.

Transcriptional effects of colony-stimulating factor-1 in mouse macrophages.

Colony-stimulating factor-1 (CSF-1) is a major regulator of macrophage development. CSF-1-dependent signalling has been implicated in proliferation, survival, and differentiation of mononuclear phagocytes, however, relatively little is known about the effects of CSF-1 on macrophage gene transcription and on CSF-1-responsive gene promoters. We used a combination of transcription profiling and in silico motif search to characterize genes that are regulated in mature bone marrow-derived macrophages cultured in the presence or absence of CSF-1.

Allele-specific DNA methylation in mouse strains is mainly determined by cis-acting sequences.

DNA methylation is a vital epigenetic mark that participates in establishing and maintaining chromatin structures and regulates gene transcription during mammalian development and cellular differentiation. Differences in epigenetic patterns between individuals may contribute to phenotypic variation and disease susceptibility; however, little is known about the extent of such variation or how different epigenetic patterns are established. Here we have compared DNA methylation profiles of macrophages from two inbred mouse strains (C57BL/6 and BALB/c) at 181 large genomic intervals that were selected based on differential gene expression patterns.

CCAAT enhancer-binding protein beta regulates constitutive gene expression during late stages of monocyte to macrophage differentiation.

Human monocyte to macrophage differentiation is accompanied by pronounced phenotypical changes and generally proceeds in the absence of proliferation. The molecular events governing this process are poorly understood. Here, we studied the regulation of the macrophage-specific chitotriosidase (CHIT1) gene promoter to gain insights into the mechanisms of transcriptional control during the differentiation of human blood monocytes into macrophages.

Transcription factor Tfec contributes to the IL-4-inducible expression of a small group of genes in mouse macrophages including the granulocyte colony-stimulating factor receptor.

Expression of the mouse transcription factor EC (Tfec) is restricted to the myeloid compartment, suggesting a function for Tfec in the development or function of these cells. However, mice lacking Tfec develop normally, indicating a redundant role for Tfec in myeloid cell development. We now report that Tfec is specifically induced in bone marrow-derived macrophages upon stimulation with the Th2 cytokines, IL-4 and IL-13, or LPS.