BackgroundLarge-scale RNAi screening has become an important technology for identifying genes involved in biological processes of interest. However, the quality of large-scale RNAi screening is often deteriorated by off-targets effects. In order to find statistically significant effector genes for pathogen entry, we systematically analyzed entry pathways in human host cells for eight pathogens using image-based kinome-wide siRNA screens with siRNAs from three vendors. We propose a Parallel Mixed Model (PMM) approach that simultaneously analyzes several non-identical screens performed with the same RNAi libraries.ResultsWe show that PMM gains statistical power for hit detection due to parallel screening. PMM allows incorporating siRNA weights that can be assigned according to available information on RNAi quality. Moreover, PMM is able to estimate a sharedness score that can be used to focus follow-up efforts on generic or specific gene regulators. By fitting a PMM model to our data, we found several novel hit genes for most of the pathogens studied.ConclusionsOur results show parallel RNAi screening can improve the results of individual screens. This is currently particularly interesting when large-scale parallel datasets are becoming more and more publicly available. Our comprehensive siRNA dataset provides a public, freely available resource for further statistical and biological analyses in the high-content, high-throughput siRNA screening field.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-1162) contains supplementary material, which is available to authorized users.

Highlights d Genome-wide RNAi screen identifies host factors boosting or inhibiting AdV entry d The E3 ubiquitin ligase Mib1 enhances entry of AdVs from different species d Ubiquitination activity of Mib1 licenses AdV uncoating at the nuclear pore complex d Mib1 at NPC-docked AdVs releases viral DNA into nucleus and cytosol ''on demand''

BackgroundUnder physiological conditions, the melanocortin system is a crucial part of the complex network regulating food intake and energy expenditure. In pathological states, like cachexia, these two parameters are deregulated, i.e., food intake is decreased and energy expenditure is increased—a vicious combination leading to catabolism. Agouti-related protein (AgRP), the endogenous antagonist at the melanocortin-4 receptor (MC-4R), was found to increase food intake and to reduce energy expenditure. This qualifies MC-4R blockade as an attractive mode of action for the treatment of cachexia. Based on this rationale, a novel series of small-molecule MC-4R antagonists was designed, from which the orally active compound BL-6020/979 (formerly known as SNT207979) emerged as the first promising development candidate showing encouraging pre-clinical efficacy and safety properties which are presented here.Methods and resultsBL-6020/979 is an orally available, selective and potent MC-4R antagonist with a drug-like profile. It increased food intake and decreased energy expenditure in healthy wild-type but not in MC-4R deficient mice. More importantly, it ameliorated cachexia-like symptoms in the murine C26 adenocarcinoma model; with an effect on body mass and body composition and on the expression of catabolic genes. Moreover, BL-6020/979 showed antidepressant-like properties in the chronic mild stress model in rats and exhibits a favorable safety profile.ConclusionThe properties of BL-6020/979 demonstrated in animal models and presented here make it a promising candidate suitable for further development towards a first-in-class treatment option for cachexia that potentially opens up the opportunity to treat two hallmarks of the disease, i.e., decreased food intake and increased energy expenditure, with one drug.

Ketone bodies (KBs) are crucial energy substrates during states of low carbohydrate availability. However, an aberrant regulation of KB homeostasis can lead to complications such as diabetic ketoacidosis. Exercise and diabetes affect systemic KB homeostasis, but the regulation of KB metabolism is still enigmatic. In our study in mice with either knockout or overexpression of the peroxisome proliferator-activated receptor-g coactivator (PGC)-1a in skeletal muscle, PGC-1a regulated ketolytic gene transcription in muscle. Furthermore, KB homeostasis of these mice was investigated during withholding of food, exercise, and ketogenic diet feeding, and after streptozotocin injection. In response to these ketogenic stimuli, modulation of PGC-1a levels in muscle affected systemic KB homeostasis. Moreover, the data demonstrate that skeletal muscle PGC-1a is necessary for the enhanced ketolytic capacity in response to exercise training and overexpression of PGC-1a in muscle enhances systemic ketolytic capacity and is sufficient to ameliorate diabetic hyperketonemia in mice. In cultured myotubes, the transcription factor estrogen-related receptor-a was a partner of PGC-1a in the regulation of ketolytic gene transcription. These results demonstrate a central role of skeletal muscle PGC-1a in the transcriptional regulation of systemic ketolytic capacity.-Svensson, K., Albert, V., Cardel, B., Salatino, S., Handschin, C. Skeletal muscle PGC-1a modulates systemic ketone body homeostasis and ameliorates diabetic hyperketonemia in mice. FASEB J. 30, 1976FASEB J. 30, -1986FASEB J. 30, (2016 During prolonged starvation, when carbohydrate availability is low, the ketone bodies (KBs) b-hydroxybutyrate (bOHB) and acetoacetate (AcAc) are necessary metabolic fuels that help maintain energy homeostasis (1). KBs are produced in the liver and are subsequently metabolized to acetyl-CoA in extrahepatic organs. Most KB metabolism occurs in the mitochondria and is catalyzed by the enzymes 3-hydroxybutyrate dehydrogenase, type 1 (BDH1), succinyl-CoA:3-ketoacid-coenzyme A transferase 1 (OXCT1), and acetyl-CoA acetyltransferase 1 (ACAT1) (2). Mutations of genes encoding these enzymes are associated with exacerbated ketosis in humans (3). Moreover, knockout of the rate-limiting ketolytic enzyme OXCT1 leads to severe hyperketonemia and lethality in mice (4). Hyperketonemia is a common complication in diabetes that can lead to severe and possibly lethal ketoacidosis (5) and has been attributed in part to impaired peripheral KB oxidation (6). However, relatively little is known about the transcriptional regulation of ketolytic enzymes (7). The peroxisome proliferator-activated receptor g coactivator (PGC)-1a is an essential transcriptional coactivator and has a well-established role in the regulation of mitochondrial metabolic processes such as oxidative phosphorylation and the tricarboxylic acid (TCA) cycle (8). Although these metabolic pathways are crucial for complete oxidation of KBs, it is not known whether PGC-1a directly affects the ...

BackgroundThe myogenic capacity of satellite cells (SCs), adult muscle stem cells, is influenced by aging, exercise, and other factors. In skeletal muscle, the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is a key regulator of oxidative metabolism and endurance training adaptation. However, a link between PGC-1α and SC behavior remains unexplored.MethodsWe have now studied SC function in a PGC-1α fiber-specific gain-of-function animal model.ResultsIn surprising contrast to bona fide exercise, muscle-specific PGC-1α transgenic mice have lower SC numbers. Nevertheless, SCs from these mice have a higher propensity for activation and proliferation. Intriguingly, muscle PGC-1α triggers a remodeling of the SC niche by altering the extracellular matrix composition, including the levels of fibronectin, which affects the proliferative output of SCs.ConclusionsTaken together, PGC-1α indirectly affects SC plasticity in skeletal muscle and thereby might contribute to improved SC activation in exercise.Electronic supplementary materialThe online version of this article (doi:10.1186/s13395-016-0111-9) contains supplementary material, which is available to authorized users.