Drosophila Genome-wide Obesity Screen Reveals Hedgehog as a Determinant of Brown versus White Adipose Cell Fate

Pospisilik, J. Andrew; Schramek, Daniel; Schnidar, Harald; Cronin, Shane J. F.; Nehme, Nadine T.; Zhang, Xiaoyun; Knauf, Claude; Cani, Patrice D.; Aumayr, Karin; Todoric, Jelena; Bayer, Martina; Haschemi, Arvand; Puviindran, Vijitha; Tar, Krisztina; Orthofer, Michael; Neely, G. Gregory; Dietzl, Georg; Manoukian, Armen S.; Funovics, Martin; Prager, Gerhard; Wagner, Oswald; Ferrandon, Dominique; Aberger, Fritz; Hui, Chi Chung; Esterbauer, Harald; Penninger, Josef

doi:10.1016/j.cell.2009.12.027

Cited by 346 publications

(354 citation statements)

References 64 publications

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“…The ␣P0-Cre transgenic mice, which express Crerecombinase under the control of the ␣P0 element of the Pax6 promoter, were obtained from Dr. P Gruss (Max-Planck Institute, Gottingen, Germany) (Marquardt et al, 2001) and were maintained on a C57BL/6 background. Sufu F/F mice harbor loxP sites flanking Sufu exons 4 -8 (Pospisilik et al, 2010) and were maintained on a C57BL/6 background. Retina-restricted conditional Sufu knock-out mice were generated by crossing ␣P0-Cre;Sufu ϩ/Fl mice with Sufu F/F mice to generate Cre;Sufu…”

Section: Methodsmentioning

confidence: 99%

Suppressor of Fused Is Required to Maintain the Multipotency of Neural Progenitor Cells in the Retina

Cwinn¹,

Mazerolle²,

McNeill³

et al. 2011

J. Neurosci.

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The morphogen sonic hedgehog (Shh) plays a crucial role in development of the CNS, including the neural retina. Suppressor of fused (Sufu) has been recently identified as a critical regulator of Hh signaling in mammals. However, the precise roles that Sufu plays in the regulation of proliferation and cell-fate decisions in neural progenitors is unknown. Here, we have addressed these questions by conditionally deleting Sufu in mouse multipotent retinal progenitor cells (RPCs). Sufu deletion in RPCs results in transient increases in Hh activity and proliferation followed by developmentally premature cell-cycle exit. Importantly, we demonstrate a novel role for Sufu in the maintenance of multipotency in RPCs. Sufu-null RPCs downregulate transcription factors required to specify or maintain RPC identity (Rax, Vsx2) and multipotency (Pax6) but continue to express the neural progenitor marker Sox2. These cells fail to express retinal lineage-specific transcription factors, such as Math5, and adopt an amacrine or horizontal cell fate at the expense of all other classes of retinal neurons. Genetic elimination of Gli2 in Sufu-null RPCs attenuates Hh pathway activity and restores multipotency in neural progenitors. These data provide novel evidence that Sufu-mediated antagonism of Hh/Gli2 signaling is required to maintain RPC multipotency and identity.

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Section: Methodsmentioning

confidence: 99%

Suppressor of Fused Is Required to Maintain the Multipotency of Neural Progenitor Cells in the Retina

Cwinn¹,

Mazerolle²,

McNeill³

et al. 2011

J. Neurosci.

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“…In addition, screens in Drosophila larvae (44) and adult flies (45) identified genes that function in fat storage. We expected that some of the LD proteins we identified would perform important functions for normal LD morphology and/or fat storage.…”

Section: Comparing the Ld Pcp And Other Ld Proteome Studiesseveral Prmentioning

confidence: 99%

Protein Correlation Profiles Identify Lipid Droplet Proteins with High Confidence

Krahmer

Hilger

Kory

et al. 2013

Molecular & Cellular Proteomics

153

165

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Lipid droplets (LDs) are important organelles in energy metabolism and lipid storage. Their cores are composed of neutral lipids that form a hydrophobic phase and are surrounded by a phospholipid monolayer that harbors specific proteins. Most well-established LD proteins perform important functions, particularly in cellular lipid metabolism. Morphological studies show LDs in close proximity to and interacting with membrane-bound cellular organelles, including the endoplasmic reticulum, mitochondria, peroxisomes, and endosomes. Because of these close associations, it is difficult to purify LDs to homogeneity. Consequently, the confident identification of bona fide LD proteins via proteomics has been challenging. Here, we report a methodology for LD protein identification based on mass spectrometry and protein correlation profiles. Using LD purification and quantitative, high-resolution mass spectrometry, we identified LD proteins by correlating their purification profiles to those of known LD proteins. Application of the protein correlation profile strategy to LDs isolated from Drosophila S2 cells led to the identification of 111 LD proteins in a cellular LD fraction in which 1481 proteins were detected. LD localization was confirmed in a subset of identified proteins via microscopy of the expressed proteins, thereby validating the approach. Among the identified LD proteins were both well-characterized LD proteins and proteins not previously known to be localized to LDs. Our method provides a high-confidence LD proteome of Drosophila cells and a novel approach that can be applied to identify LD proteins of other cell types and tissues. This analytic problem is particularly apparent for lipid droplets (LDs). LD architecture differs from that of other organelles in that they have hydrophobic cores of neutral lipids, primarily triacylglycerol and sterol esters, rather than an aqueous lumen. The LD core is shielded from the cytosol by a phospholipid monolayer, into which specific proteins are embedded (4 -6). The primary function of LDs is to store lipids as reservoirs of metabolic energy and membrane precursors. Additionally, LDs participate in host-pathogen interactions (7) and play central roles in numerous physiological processes and linked pathologies. For example, obesity is characterized by the overaccumulation of LDs in tissues, and LD accumulation in macrophages is a hallmark of atherosclerosis (8, 9). Given the diverse distribution of LDs in cell types and processes, their protein composition likely varies among cell types and is dynamic. Knowledge of LD compositions in different cell types will lay the foundation for functional characterization of this organelle and could help to reveal novel mechanisms contributing to metabolic diseases.LD protein composition has been analyzed in over a dozen studies that employed different methodologies to study different cell types ranging in evolutionary complexity from yeast to human (10 -21). These studies have provided long lists of putative LD proteins, but apart f...

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“…Drosophila provides a powerful model system for the genetic analysis of obesity (9)(10)(11). The processes that regulate energy homeostasis, such as energy storage and mobilization of fat in adipose tissue of the fat body, as well as the genetic pathways governing such functions, are conserved in flies (12).…”

mentioning

confidence: 99%

Heart- and muscle-derived signaling system dependent on MED13 and Wingless controls obesity in Drosophila

Lee

Bassel‐Duby

Olson

2014

Proc. Natl. Acad. Sci. U.S.A.

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Obesity develops in response to an imbalance of energy homeostasis and whole-body metabolism. Muscle plays a central role in the control of energy homeostasis through consumption of energy and signaling to adipose tissue. We reported previously that MED13, a subunit of the Mediator complex, acts in the heart to control obesity in mice. To further explore the generality and mechanistic basis of this observation, we investigated the potential influence of MED13 expression in heart and muscle on the susceptibility of Drosophila to obesity. Here, we show that heart/muscle-specific knockdown of MED13 or MED12, another Mediator subunit, increases susceptibility to obesity in adult flies. To identify possible muscle-secreted obesity regulators, we performed an RNAi-based genetic screen of 150 genes that encode secreted proteins and found that Wingless inhibition also caused obesity. Consistent with these findings, muscle-specific inhibition of Armadillo, the downstream transcriptional effector of the Wingless pathway, also evoked an obese phenotype in flies. Epistasis experiments further demonstrated that Wingless functions downstream of MED13 within a muscle-regulatory pathway. Together, these findings reveal an intertissue signaling system in which Wingless acts as an effector of MED13 in heart and muscle and suggest that Wingless-mediated cross-talk between striated muscle and adipose tissue controls obesity in Drosophila. This signaling system appears to represent an ancestral mechanism for the control of systemic energy homeostasis.O besity is a systemic disorder caused by an energy imbalance in which energy input exceeds energy utilization, resulting in accumulation of excess body fat. Muscle plays a central role in systemic energy homeostasis by consuming nutrients and signaling in an endocrine manner to other tissues (1-3). Thus, there has been intense interest in identifying secreted factors from muscle that modulate the function of adipose tissue.Previously, we reported that cardiac deletion of MED13, a subunit of the Mediator complex, increases susceptibility to obesity in mice whereas cardiac overexpression of MED13 confers a lean phenotype (4), revealing an unforeseen function of the heart as a systemic regulator of energy homeostasis. The Mediator is a conserved multisubunit complex that mediates the interaction between RNA polymerase II and transcription factors and therefore governs transcription in all eukaryotes (5). MED13 and MED12 are among four subunits of the auxiliary kinase module, which confers additional regulatory functions to the Mediator complex (6). Expression profiling of yeast mutants or gene-depleted Drosophila cell lines revealed a close correlation between the gene-expression programs controlled by MED13 and MED12, suggesting their concerted actions in gene regulation (7,8).Drosophila provides a powerful model system for the genetic analysis of obesity (9-11). The processes that regulate energy homeostasis, such as energy storage and mobilization of fat in adipose tissue of the fat bo...

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Drosophila Genome-wide Obesity Screen Reveals Hedgehog as a Determinant of Brown versus White Adipose Cell Fate

Cited by 346 publications

References 64 publications

Suppressor of Fused Is Required to Maintain the Multipotency of Neural Progenitor Cells in the Retina

Suppressor of Fused Is Required to Maintain the Multipotency of Neural Progenitor Cells in the Retina

Protein Correlation Profiles Identify Lipid Droplet Proteins with High Confidence

Heart- and muscle-derived signaling system dependent on MED13 and Wingless controls obesity in Drosophila

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