Macrophages are myeloid lineage cells that reside in virtually all tissues of the body and play essential roles in immunity, tissue homeostasis and wound repair. Responses to bacterial and viral infection are associated with a 'classical' program of macrophage activation involving NF?B and other signal-dependent transcription factors that direct expression of genes that promote inflammation and initiate innate and adaptive immune responses. Low-grade forms of classical macrophage activation are causally linked to the pathogenesis of numerous inflammatory diseases that include type 2 diabetes. Conversely, resident macrophages in healthy adipose tissue exhibit features of an 'alternative' program of macrophage activation, involving the IL4/ STAT6/PPAR??axis. The STAT6/PPAR?-dependent transcriptional program is linked to expression of genes that actively maintain tissue homeostasis and insulin sensitivity. Although the pathways responsible for classical and alternative activation are highly conserved, individual variation in the functional responses of these pathways is proposed to influence risk for diseases in which inflammation plays a pathogenic role. In this application, we propose to build on recent conceptual and technical advances and the vast natural genetic variation provided by inbred strains of mice to comprehensively decode the transcriptional circuitry underlying classical and alternative macrophage activation. These studies will test and extend a general collaborative/hierarchical model for the selection and function of signal-dependent enhancers required for the transcriptional outputs of NF?B and PPAR??through three Specific Aims.
Specific Aim 1 will leverage the >50 million SNPs provided by 5 inbred strains of mice to identify the collaborating transcription factors required for the genome-wide binding patterns of NF?B and PPAR??in classically or alternatively activated macrophages, respectively.
Specific Aim 2 will extend these studies to define the requirements for the transition from transcription factor binding to enhancer activation.
This aim i s based on the hypothesis that an essential feature of a functional enhancer is that it is actively transcribed.
Specific Aim 3 will use a novel form of network modeling informed by effects of natural genetic variation and chromatin connectivity maps to functionally link specific enhancers to target genes. General predictions regarding the modularity of NF?B and PPAR?-activated enhancers will be tested in human macrophages. If successful, these studies will result in qualitative advances in our understanding of classical and alternative macrophage activation, enable insights into effects of natural genetic variation on these responses and disease, and provide a general approach for decoding the transcriptional regulatory circuitry for any signal-dependent program of gene expression in any cell type.

Public Health Relevance

Classically activated macrophages contribute to insulin resistance, while alternatively activated macrophages contribute to insulin sensitivity. Natural genetic variation that alters responses to these forms of macrophage activation is proposed to influence risk of development of type 2 diabetes and other forms of metabolic disease. The proposed studies will greatly advance our understanding of effects of genetic variation on transcriptional mechanisms controlling macrophage phenotypes that influence tissue homeostasis and disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK091183-28
Application #
9412459
Study Section
Molecular and Cellular Endocrinology Study Section (MCE)
Program Officer
Silva, Corinne M
Project Start
1991-04-01
Project End
2020-01-31
Budget Start
2018-02-01
Budget End
2019-01-31
Support Year
28
Fiscal Year
2018
Total Cost
Indirect Cost
Name
University of California San Diego
Department
Other Basic Sciences
Type
Schools of Medicine
DUNS #
804355790
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Oishi, Yumiko; Spann, Nathanael J; Link, Verena M et al. (2017) SREBP1 Contributes to Resolution of Pro-inflammatory TLR4 Signaling by Reprogramming Fatty Acid Metabolism. Cell Metab 25:412-427
Phan, Anthony T; Goldrath, Ananda W; Glass, Christopher K (2017) Metabolic and Epigenetic Coordination of T Cell and Macrophage Immunity. Immunity 46:714-729
Stender, Joshua D; Nwachukwu, Jerome C; Kastrati, Irida et al. (2017) Structural and Molecular Mechanisms of Cytokine-Mediated Endocrine Resistance in Human Breast Cancer Cells. Mol Cell 65:1122-1135.e5
Eichenfield, Dawn Z; Troutman, Ty Dale; Link, Verena M et al. (2016) Tissue damage drives co-localization of NF-?B, Smad3, and Nrf2 to direct Rev-erb sensitive wound repair in mouse macrophages. Elife 5:
Fonseca, Gregory J; Seidman, Jason S; Glass, Christopher K (2016) Genome-Wide Approaches to Defining Macrophage Identity and Function. Microbiol Spectr 4:
Thomas, Graham D; Hanna, Richard N; Vasudevan, Neelakatan T et al. (2016) Deleting an Nr4a1 Super-Enhancer Subdomain Ablates Ly6ClowMonocytes while Preserving Macrophage Gene Function. Immunity 45:975-987
Allison, Karmel A; Sajti, Eniko; Collier, Jana G et al. (2016) Affinity and dose of TCR engagement yield proportional enhancer and gene activity in CD4+ T cells. Elife 5:
Glass, Christopher K; Natoli, Gioacchino (2016) Molecular control of activation and priming in macrophages. Nat Immunol 17:26-33
Shaked, Iftach; Hanna, Richard N; Shaked, Helena et al. (2015) Transcription factor Nr4a1 couples sympathetic and inflammatory cues in CNS-recruited macrophages to limit neuroinflammation. Nat Immunol 16:1228-34
Link, Verena M; Gosselin, David; Glass, Christopher K (2015) Mechanisms Underlying the Selection and Function of Macrophage-Specific Enhancers. Cold Spring Harb Symp Quant Biol 80:213-21

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