A Spatial and Temporal Analysis of MCH Signaling in the Developing Adipocyte

About This Grant

Project Summary/Abstract Melanin-concentrating hormone (MCH) helps control human sleep, appetite and energy expenditure, anxiety, and mood. Localization of its receptor, MCHR1, to primary cilia seems critical of its physiological role because both ciliopathies and short cilia correlate with the obese phenotype. We’ve shown that MCHR1 also localizes to a transient primary cilium during differentiation of 3T3-L1 adipocytes, and that MCH signaling is changed while the receptor is in the cilium. This transient, ciliary-localization behavior of MCHR1 is not seen in most neuronal cells expressing the receptor, and it creates a useful model system for studying signaling inside and outside of the ciliary environment. Our central hypothesis is that MCHR1 signaling is adaptable to its cellular microenvironment, intersecting with different signaling pathways as the tissue develops to control adipogenesis. Furthermore, we predict that the release of pro-inflammatory cytokines from adipose tissue is enhanced by MCH, but only during specific developmental stages of adipocyte differentiation. In Aim 1, we will decipher MCH- derived signaling pathways targeting actin filament rearrangements by testing the hypothesis that MCHR1 migration into primary cilia reverses how MCH signals to the actin cytoskeleton using a collection of simple assays to study signaling to Arf6/ARNO, RhoA, MKL1 and G/F-actin pool ratios. In Aim 2, we will elucidate the spatial and/or interactome differences regulating MCHR1 signaling in primary cilia by exploring G protein bias, β-arrestin recruitment patterns and co-localization with potential signaling partners. Finally, In Aim 3, we will explore the role of MCH in building and maintaining an adipose tissue infrastructure by determining how MCH influences several immunoregulatory genes during adipocyte differentiation and we’ll test MCH-induced 3T3-L1 secretions for macrophage recruitment and biofilm formation. The proposal is significant is it designed to engage undergraduate and master’s students in a mentored research environment, but also addresses important questions about the impact of subcellular localization on G protein-coupled receptor signaling within the context of obesity.