Dysregulation of blood glucose and triglycerides are the major characteristics of type 2 diabetes mellitus. We sought to identify the mechanisms regulating blood glucose and lipid homeostasis. Cell-based studies established that the Foxo forkhead transcription factors Forkhead box O (Foxo)-1, Foxo3, and Foxo4 are inactivated by insulin via a phosphatidylinositol 3-kinase/Akt-dependent pathway, but the role of Foxo transcription factors in the liver in regulating nutrient metabolism is incompletely understood. In this study, we used the Cre/LoxP genetic approach to delete the Foxo1, Foxo3, and Foxo4 genes individually or a combination of two or all in the liver of lean or db/db mice and assessed the role of Foxo inactivation in regulating glucose and lipid homeostasis in vivo. In the lean mice or db/db mice, hepatic deletion of Foxo1, rather than Foxo3 or Foxo4, caused a modest reduction in blood glucose concentrations and barely affected lipid homeostasis. Combined deletion of Foxo1 and Foxo3 decreased blood glucose levels, elevated serum triglyceride and cholesterol concentrations, and increased hepatic lipid secretion and caused hepatosteatosis. Analysis of the liver transcripts established a prominent role of Foxo1 in regulating gene expression of gluconeogenic enzymes and Foxo3 in the expression of lipogenic enzymes. Our findings indicate that Foxo1 and Foxo3 inactivation serves as a potential mechanism by which insulin reduces hepatic glucose production and increases hepatic lipid synthesis and secretion in healthy and diabetic states.

Cardiac failure is a major cause of death in patients with type 2 diabetes, but the molecular mechanism that links diabetes to heart failure remains unclear. Insulin resistance is a hallmark of type 2 diabetes, and insulin receptor substrates 1 and 2 (IRS1 and IRS2) are the major insulin-signaling components regulating cellular metabolism and survival. To determine the role of IRS1 and IRS2 in the heart and examine whether hyperinsulinemia causes myocardial insulin resistance and cellular dysfunction via IRS1 and IRS2, we generated heart-specific IRS1 and IRS2 gene double-knockout (H-DKO) mice and liver-specific IRS1 and IRS2 double-knockout (L-DKO) mice. H-DKO mice had reduced ventricular mass; developed cardiac apoptosis, fibrosis, and failure; and showed diminished Akt→forkhead box class O-1 signaling that was accompanied by impaired cardiac metabolic gene expression and reduced ATP content. L-DKO mice had decreased cardiac IRS1 and IRS2 proteins and exhibited features of heart failure, with impaired cardiac energy metabolism gene expression and activation of p38α mitogen-activated protein kinase (p38). Using neonatal rat ventricular cardiomyocytes, we further found that chronic insulin exposure reduced IRS1 and IRS2 proteins and prevented insulin action through activation of p38, revealing a fundamental mechanism of cardiac dysfunction during insulin resistance and type 2 diabetes.

The past decade has seen a revolution in genomic technologies that enabled a flood of genome-wide profiling of chromatin marks. Recent literature tried to understand gene regulation by predicting gene expression from large-scale chromatin measurements. Two fundamental challenges exist for such learning tasks: (1) genome-wide chromatin signals are spatially structured, high-dimensional and highly modular; and (2) the core aim is to understand what the relevant factors are and how they work together. Previous studies either failed to model complex dependencies among input signals or relied on separate feature analysis to explain the decisions. This paper presents an attention-based deep learning approach, AttentiveChrome, that uses a unified architecture to model and to interpret dependencies among chromatin factors for controlling gene regulation. AttentiveChrome uses a hierarchy of multiple Long Short-Term Memory (LSTM) modules to encode the input signals and to model how various chromatin marks cooperate automatically. AttentiveChrome trains two levels of attention jointly with the target prediction, enabling it to attend differentially to relevant marks and to locate important positions per mark. We evaluate the model across 56 different cell types (tasks) in humans. Not only is the proposed architecture more accurate, but its attention scores provide a better interpretation than state-of-the-art feature visualization methods such as saliency maps.1

Background-Heart failure is a leading cause of morbidity and mortality in the USA and is closely associated with diabetes mellitus. The molecular link between diabetes mellitus and heart failure is incompletely understood. We recently demonstrated that insulin receptor substrates 1, 2 (IRS1, 2) are key components of insulin signaling and loss of IRS1 and IRS2 mediates insulin resistance, resulting in metabolic dysregulation and heart failure, which is associated with downstream Akt inactivation and in turn activation of the forkhead transcription factor Foxo1. Methods and Results-To determine the role of Foxo1 in control of heart failure in insulin resistance and diabetes mellitus, we generated mice lacking Foxo1 gene specifically in the heart. Mice lacking both IRS1 and IRS2 in adult hearts exhibited severe heart failure and a remarkable increase in the β-isoform of myosin heavy chain (β-MHC) gene expression, whereas deletion of cardiac Foxo1 gene largely prevented the heart failure and resulted in a decrease in β-MHC expression. The effect of Foxo1 deficiency on rescuing cardiac dysfunction was also observed in db/db mice and high-fat diet mice. Using cultures of primary ventricular cardiomyocytes, we found that Foxo1 interacts with the promoter region of β-MHC and stimulates gene expression, mediating an effect of insulin that suppresses β-MHC expression. Conclusions-Our study suggests that Foxo1 has important roles in promoting diabetic cardiomyopathy and controls β-MHC expression in the development of cardiac dysfunction. Targeting Foxo1 and its regulation will provide novel strategies in preventing metabolic and myocardial dysfunction and influencing MHC plasticity in diabetes mellitus. (Circ Heart Fail.

Previous studies have demonstrated that benzo(a)pyrene (BaP) may disrupt the development of key biological systems, thus leaving children more vulnerable to functional impairments in adulthood. The current study was conducted to determine whether neurotoxic effects of postnatal BaP exposure on behavioral performance persist in juvenile and young adult stages. Therefore, neonate Sprague-Dawley pups were given oral doses of BaP (0.02, 0.2, and 2 mg/kg/day) continuing through a period of rapid brain development (on postnatal days [PNDs] 5-11). Further, developmental milestones and behavioral endpoints assessing sensory and motor maturation were examined. Also, in this study, Morris water maze and elevated plus maze were used for evaluating the cognitive function and anxiety-like behavior. Our results showed that there was altered ontogeny in a few measures of neuromotor development; however, other developmental milestones and sensory responses were not altered significantly. Moreover, the locomotor activity deficit in BaP-treated pups was evident at PND 36 and was most pronounced in the PND 69. Also, exposure to BaP during early postnatal development had an adverse effect on adult rats (PND 70) in the elevated plus maze, and the swim maze suggests that low doses of BaP impair spatial learning functions at adult test period. In contrast, BaP exposure had no evident effect on behaviors in these two mazes for adolescent animals. These data clearly indicate that behavioral impairments resulting from postnatal BaP exposure are potentially long-lasting and may not be apparent in juveniles, but are present in young adulthood.

Dysregulation of hepatic glucose production (HGP) serves as a major underlying mechanism for the pathogenesis of type 2 diabetes. The pancreatic hormone glucagon increases and insulin suppresses HGP, controlling blood glucose homeostasis. The forkhead transcription factor Foxo1 promotes HGP through increasing expression of genes encoding the rate-limiting enzymes responsible for gluconeogenesis. We previously established that insulin suppresses Foxo1 by Akt-mediated phosphorylation of Foxo1 at Ser in human hepatocytes. In this study, we found a novel Foxo1 regulatory mechanism by glucagon, which promotes Foxo1 nuclear translocation and stability via cAMP- and protein kinase A-dependent phosphorylation of Foxo1 at Ser Replacing Foxo1-S276 with alanine (A) or aspartate (D) to block or mimic phosphorylation, respectively, markedly regulates Foxo1 stability and nuclear localization in human hepatocytes. To establish in vivo function of Foxo1-Ser phosphorylation in glucose metabolism, we generated Foxo1-S273A and Foxo1-S273D knock-in (KI) mice. The KI mice displayed impaired blood glucose homeostasis, as well as the basal and glucagon-mediated HGP in hepatocytes. Thus, Foxo1-Ser is a new target site identified in the control of Foxo1 bioactivity and associated metabolic diseases.

A severe disease in humans caused by a novel avian-origin influenza A (H7N9) virus emerged in China recently, which has caused at least 128 cases and 26 deaths. Rapid detection of the novel H7N9 virus is urgently needed to differentiate the disease from other infections, and to facilitate infection control as well as epidemiologic investigations. In this study, a reverse transcription loop-mediated isothermal amplification combined with a lateral flow device (RT-LAMP-LFD) assay to rapidly detect H7N9 virus was developed and evaluated. The RT-LAMP primers were designed to target the haemagglutinin (HA) and neuraminidase (NA) genes of H7N9 virus. Results of 10-fold dilution series assays showed that analysis of RT-LAMP products by the LFD method was as sensitive as real-time turbidity detection, and that the analytic sensitivities of the HA and NA RT-LAMP assays were both 10 copies of synthetic RNA. Furthermore, both the assays showed 100% clinical specificity for identification of H7N9 virus. The performance characteristics of the RT-LAMP-LFD assay were evaluated with 80 clinical specimens collected from suspected H7N9 patients. The NA RT-LAMP-LFD assay was more sensitive than real time RT-PCR assay. Compared with a combination of virus culture and real-time RT-PCR, the sensitivity, specificity, positive predictive value, and negative predictive value of the RT-LAMP-LFD assay were all 100%. Overall, The RT-LAMP-LFD assay established in this study can be used as a reliable method for early diagnosis of the avian-origin influenza A (H7N9) virus infection.

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