We have determined the relative value of the features of the metabolic syndrome in childhood for the prediction of subsequent type 2 diabetes. Our findings suggest that strategies targeting obesity, dysregulated glucose homeostasis, and low HDL cholesterol during childhood and adolescence may have the most success in preventing diabetes.

Lipid homeostasis in vertebrates is regulated by 3 sterol regulatory element binding protein (SREBP) isoforms. Here, we identify targets of SREBP-1 in mammalian liver using chromatin immunoprecipitation-high-throughput DNA sequencing. Antisera to SREBP-1 were used with liver chromatin from mice fed a high-carbohydrate diet after a fast, which leads to superinduction of hepatic SREBP-1c expression. SREBP-1-DNA complexes were subjected to massive parallel DNA sequencing using the Illumina Genome Analyzer II, resulting in 5.7 million sequence reads. Mapping these reads to the mouse reference genome identified 426 peaks of SREBP-1 binding vs. a control antibody. These binding peaks show a striking enrichment in proximal promoter regions, with 52% located within 1 kb upstream of a transcription start site. A previously undescribed sequence motif (5-ACTACANNTCCC-3) was present in 76% of the total peaks, and we show that it is a functional SREBP-1 response element. Our analysis also reveals that an Sp1 consensus site is present as a ''coregulatory'' motif in 50% of the SREBP-1 binding peaks, consistent with previous functional studies. SREBP-1 bound not only to many well-characterized SREBP-1 target genes but to several other previously unknown targets in lipid and carbohydrate metabolism as well as many putative target genes in other diverse biological pathways.ChIP-seq ͉ fasting/refeeding ͉ Sp1 ͉ Kolmogorov-Smirnov test A ll living organisms have evolved strategic regulatory systems to coordinate metabolic flux into potentially competing biochemical pathways to manage metabolite and end-product pools for optimal cellular fitness. This is particularly important in mammalian lipid homeostasis because cholesterol and fatty acids, the 2 major classes of mammalian lipids, are key to the structure and function of all cells, and unbalanced flux into these pathways can be both energy-inefficient and toxic. In vertebrates, lipid homeostasis is maintained in part by sterol regulatory element binding protein (SREBP) transcription factors, which are synthesized as Ϸ125-kDa precursors containing 2 membrane-spanning domains that localize the immature proteins to the endoplasmic reticulum membrane (1).Overlapping transcripts from 1 gene encode SREBP-1a and SREBP-1c isoforms, and the singular SREBP-2 is encoded from a distinct unlinked gene (2). There is an intricate system of nutrient sensing that relates cellular levels of cholesterol and other key lipid components to the expression and multistep membrane trafficking/protease pathway that converts the membrane-bound SREBPs into the much smaller nuclear targeted transcription factors.SREBPs activate genes encoding most of the key enzymes in cholesterol and fatty acid metabolism (3); thus, coupling SREBP processing to pathway flux provides a direct link between the activity of the regulatory factors and metabolic demand. Overexpression and targeted elimination studies in mice have produced crucial information on the roles of SREBPs in lipid regulation (3).The available evidence indi...

We used mouse hepatic chromatin enriched with an FXR antibody and chromatin immunoprecipitation-sequencing (ChIP-seq) to evaluate FXR binding on a genome-wide scale. This identified 1656 FXR-binding sites and 10% were located within 2 kb of a transcription start site which is much higher than predicted by random occurrence. A motif search uncovered a canonical nuclear receptor IR-1 site, consistent with in vitro DNA-binding studies reported previously. A separate nuclear receptor half-site for monomeric receptors such as LRH-1 was co-enriched and FXR activation of four newly identified promoters was significantly augmented by an LRH-1 expression vector in a co-transfection assay. There were 1038 genes located within 20 kb of a peak and a gene set enrichment analysis showed that genes identified by our ChIP-seq analysis are highly correlated with genes activated by an FXR-VP16 adenovirus in primary mouse hepatocytes providing functional relevance to the genome-wide binding study. Gene Ontology analysis showed FXR-binding sites close to many genes in lipid, fatty acid and steroid metabolism. Other broad gene clusters related to metabolism, transport, signaling and glycolysis were also significantly enriched. Thus, FXR may have a much wider role in cellular metabolism than previously appreciated.

Purpose: This study tested the hypothesis that a patientderived orthotopic xenograft (PDOX) model would recapitulate the common clinical phenomenon of breast cancer-induced skeletal muscle (SkM) fatigue in the absence of muscle wasting. This study additionally sought to identify drivers of this condition to facilitate the development of therapeutic agents for patients with breast cancer experiencing muscle fatigue. Experimental Design: Eight female BC-PDOX-bearing mice were produced via transplantation of tumor tissue from 8 female patients with breast cancer. Individual hind limb muscles from BC-PDOX mice were isolated at euthanasia for RNA-sequencing, gene and protein analyses, and an ex vivo muscle contraction protocol to quantify tumor-induced aberrations in SkM function. Differentially expressed genes (DEG) in the BC-PDOX mice relative to control mice were identified using DESeq2, and multiple bioinformatics platforms were employed to contextualize the DEGs. Results: We found that SkM from BC-PDOX-bearing mice showed greater fatigability than control mice, despite no differences in absolute muscle mass. PPAR, mTOR, IL6, IL1, and several other signaling pathways were implicated in the transcriptional changes observed in the BC-PDOX SkM. Moreover, 3 independent in silico analyses identified PPAR signaling as highly dysregulated in the SkM of both BC-PDOX-bearing mice and human patients with early-stage nonmetastatic breast cancer. Conclusions: Collectively, these data demonstrate that the BC-PDOX model recapitulates the expected breast cancer-induced SkM fatigue and further identify aberrant PPAR signaling as an integral factor in the pathology of this condition.