Transcriptional and Linkage Analyses Identify Loci that Mediate the Differential Macrophage Response to Inflammatory Stimuli and Infection

Macrophages display flexible activation states that range between pro-inflammatory (classical activation) and anti-inflammatory (alternative activation). These macrophage polarization states contribute to a variety of organismal phenotypes such as tissue remodeling and susceptibility to infectious and inflammatory diseases. Several macrophage- or immune-related genes have been shown to modulate infectious and inflammatory disease pathogenesis. However, the potential role that differences in macrophage activation phenotypes play in modulating differences in susceptibility to infectious and inflammatory disease is just emerging. We integrated transcriptional profiling and linkage analyses to determine the genetic basis for the differential murine macrophage response to inflammatory stimuli and to infection with the obligate intracellular parasite Toxoplasma gondii. We show that specific transcriptional programs, defined by distinct genomic loci, modulate macrophage activation phenotypes. In addition, we show that the difference between AJ and C57BL/6J macrophages in controlling Toxoplasma growth after stimulation with interferon gamma and tumor necrosis factor alpha mapped to chromosome 3, proximal to the Guanylate binding protein (Gbp) locus that is known to modulate the murine macrophage response to Toxoplasma. Using an shRNA-knockdown strategy, we show that the transcript levels of an RNA helicase, Ddx1, regulates strain differences in the amount of nitric oxide produced by macrophage after stimulation with interferon gamma and tumor necrosis factor. Our results provide a template for discovering candidate genes that modulate macrophage-mediated complex traits

Spatial Frames and the Quest for Institutional Fit

Spatial frames play a crucial role in debates over environmental sustainability. Building on a social scientific understanding of space, we discuss key spatial frames in biodiversity and ecosystem management, including territory, social-ecological systems, global networks and flows, and sense of place. In evaluating these frames, we argue that the state with its territorial power has clear limitations in effectively and legitimately addressing ecosystem problems, even when it remains a crucial power-container and regulator. Adapting institutional arrangements to ecosystem scale, as advocates of social-ecological systems propose, is often inappropriate because of cross-scale socio-political dynamics. Given the importance of global flows, we argue that place-based or landscape approaches that bring together local ecosystem management and global value chains present an ambivalent, but highly relevant spatial framing