The forkhead box O family consists of FoxO1, FoxO3, FoxO4 and FoxO6 proteins in mammals. Expressed ubiquitously in the body, the four FoxO isoforms share in common the amino DNA-binding domain, known ...as ‘forkhead box’ domain. They mediate the inhibitory action of insulin or insulin-like growth factor on key functions involved in cell metabolism, growth, differentiation, oxidative stress, senescence, autophagy and aging. Genetic mutations in FoxO genes or abnormal expression of FoxO proteins are associated with metabolic disease, cancer or altered lifespan in humans and animals. Of the FoxO family, FoxO6 is the least characterized member and is shown to play pivotal roles in the liver, skeletal muscle and brain. Altered FoxO6 expression is associated with the pathogenesis of insulin resistance, dietary obesity and type 2 diabetes and risk of neurodegeneration disease. FoxO6 is evolutionally divergent from other FoxO isoforms. FoxO6 mediates insulin action on target genes in a mechanism that is fundamentally different from other FoxO members. Here, we focus our review on the role of FoxO6, in contrast with other FoxO isoforms, in health and disease. We review the distinctive mechanism by which FoxO6 integrates insulin signaling to hepatic glucose and lipid metabolism. We highlight the importance of FoxO6 dysregulation in the dual pathogenesis of fasting hyperglycemia and hyperlipidemia in diabetes. We review the role of FoxO6 in memory consolidation and its contribution to neurodegeneration disease and aging. We discuss the potential therapeutic option of pharmacological FoxO6 inhibition for improving glucose and lipid metabolism in diabetes.
To identify metabolic pathways that are perturbed in pancreatic ductal adenocarcinoma (PDAC), we investigated gene-metabolite networks with integration of metabolomics and transcriptomics.
We ...conducted global metabolite profiling analysis on two independent cohorts of resected PDAC cases to identify critical metabolites alteration that may contribute to the progression of pancreatic cancer. We then searched for gene surrogates that were significantly correlated with the key metabolites, by integrating metabolite and gene expression profiles.
Fifty-five metabolites were consistently altered in tumors as compared with adjacent nontumor tissues in a test cohort (N = 33) and an independent validation cohort (N = 31). Weighted network analysis revealed a unique set of free fatty acids (FFA) that were highly coregulated and decreased in PDAC. Pathway analysis of 157 differentially expressed gene surrogates revealed a significantly altered lipid metabolism network, including key lipolytic enzymes PNLIP, CLPS, PNLIPRP1, and PNLIPRP2. Gene expressions of these lipases were significantly decreased in pancreatic tumors as compared with nontumor tissues, leading to reduced FFAs. More importantly, a lower gene expression of PNLIP in tumors was associated with poorer survival in two independent cohorts. We further showed that two saturated FFAs, palmitate and stearate, significantly induced TRAIL expression, triggered apoptosis, and inhibited proliferation in pancreatic cancer cells.
Our results suggest that impairment in a lipolytic pathway involving lipases, and a unique set of FFAs, may play an important role in the development and progression of pancreatic cancer and provide potential targets for therapeutic intervention.
A combined cellular automaton-finite difference model was applied to simulate the columnar-to-equiaxed transition (CET) during the directional solidification of Al–Cu alloys. This model provided a ...novel insight into the solutal interactions both within the advancing columnar dendritic network and within the equiaxed grains forming ahead of them. Simulations revealed that solute interaction among secondary and tertiary arms is strong, but the interaction at the columnar tips is weak. The region with the largest solute adjusted undercooling was found to be in the region between columnar dendrites, rather than ahead of their tips as assumed in prior CET models. In addition, it was found that prior simulations which neglect the solute built-up at the interface predict the CET at a significantly lower velocity for a given gradient. The effect of crystallographic orientation on CET was also simulated and was found not to be significant. The influences of thermal gradient and growth rate on CET were combined on a CET map, showing good agreement with prior theoretical models at low growth rates, while at high growth rates the current model predicts that CET will occur at lower gradients. Reasonable agreement with the limited number of experimental observations available was obtained.
Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers worldwide. To identify biologically relevant genes with prognostic and therapeutic significance in PDAC, we first performed ...the microarray gene-expression profiling in 45 matching pairs of tumor and adjacent non-tumor tissues from resected PDAC cases. We identified 36 genes that were associated with patient outcome and also differentially expressed in tumors as compared with adjacent non-tumor tissues in microarray analysis. Further evaluation in an independent validation cohort (N = 27) confirmed that DPEP1 (dipeptidase 1) expression was decreased (T:N ratio ∼0.1, P<0.01) in tumors as compared with non-tumor tissues. DPEP1 gene expression was negatively correlated with histological grade (Spearman correlation coefficient = -0.35, P = 0.004). Lower expression of DPEP1 in tumors was associated with poor survival (Kaplan Meier log rank) in both test cohort (P = 0.035) and validation cohort (P = 0.016). DPEP1 expression was independently associated with cancer-specific mortality when adjusted for tumor stage and resection margin status in both univariate (hazard ratio = 0.43, 95%CI = 0.24-0.76, P = 0.004) and multivariate analyses (hazard ratio = 0.51, 95%CI = 0.27-0.94, P = 0.032). We further demonstrated that overexpression of DPEP1 suppressed tumor cells invasiveness and increased sensitivity to chemotherapeutic agent Gemcitabine. Our data also showed that growth factor EGF treatment decreased DPEP1 expression and MEK1/2 inhibitor AZD6244 increased DPEP1 expression in vitro, indicating a potential mechanism for DPEP1 gene regulation. Therefore, we provide evidence that DPEP1 plays a role in pancreatic cancer aggressiveness and predicts outcome in patients with resected PDAC. In view of these findings, we propose that DPEP1 may be a candidate target in PDAC for designing improved treatments.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
The aims of our meta‐analysis were (i) to quantify the predictability of childhood overweight and obesity on the risk of incident asthma; and (ii) to evaluate the gender difference on this ...relationship. The selection criteria included prospective cohort paediatric studies which use age‐ and sex‐specific body mass index (BMI) as a measure of childhood overweight and the primary outcome of incident asthma. A total of 1,027 studies were initially identified through online database searches, and finally 6 studies met the inclusion criteria. The combined result of reported relative risk from the 6 included studies revealed that overweight children conferred increased risks of incident asthma as compared with non‐overweight children (relative risk, 1.19; 95% confidence interval CI, 1.03–1.37). The relationship was further elevated for obesity vs. non‐obesity (relative risk, 2.02; 95% CI, 1.16–3.50). A dose–responsiveness of elevated BMI on asthma incidence was observed (P for trend, 0.004). Obese boys had a significantly larger effect than obese girls (relative risk, boys: 2.47; 95% CI, 1.57–3.87; girls: 1.25; 95% CI, 0.51–3.03), with significant dose‐dependent effect. Proposed mechanisms of gender difference could be through pulmonary mechanics, sleep disordered breathing and leptin. Further research might be needed to better understand the exact mechanism of gender difference on the obesity–asthma relationship.
Hepatic inflammation is intertwined with insulin resistance and is a causative factor for the transition of benign steatosis to nonalcoholic steatohepatitis (NASH). We found that FoxO1 was markedly ...upregulated in hepatic macrophages, coinciding with hepatic inflammation and steatosis in dietary obese mice. We generated myeloid-conditional FoxO1-transgenic and FoxO1-knockout mice, two complementary models for determining the effect of FoxO1 gain- vs. loss-of-function on macrophage activation in response to insulin resistance. We found that myeloid FoxO1 gain-of-function aggravated hepatic inflammation in mice in response to overnutrition or endotoxin. In contrast, myeloid FoxO1 loss-of-function skewed macrophage polarization from pro-inflammatory M1 to anti-inflammatory M2 phenotypes, accompanied by the reduction of macrophage infiltration in liver. This effect contributed to the suppression of hepatic inflammation and improvement of insulin sensitivity. Despite fat-induced obesity, myeloid-conditional FoxO1-deficient mice were protected from developing hyperglycemia, hyperinsulinemia and glucose intolerance. Furthermore, the improvement in hepatic inflammation and insulin resistance translated into a significant beneficial effect on NASH, culminating in the reduction of hepatic steatosis and fibrosis in myeloid FoxO1-deficient mice on NASH-inducing diet. Human FOXO1 expression was upregulated in inflammatory macrophages in liver, correlating with hepatic inflammation, steatosis and fibrosis in patients with NASH. Mechanistically, FoxO1 counteracts Stat6 to skew macrophage polarization from M2 toward M1 signatures with pro-inflammatory profiles. We concluded that myeloid FoxO1 dysregulation is culpable for linking insulin resistance to abnormal macrophage activation. This effect perpetuates hepatic inflammation and catalyzes the evolution of simple steatosis to NASH.
Disclosure
S.Lee: None. T.Usman: None. G.Chhetri: None. X.Wang: None. H.Dong: None.
African-American breast cancer patients experience higher mortality rates than European-American patients despite having a lower incidence of the disease. We tested the hypothesis that intrinsic ...differences in the tumor biology may contribute to this cancer health disparity.
Using laser capture microdissection, we examined genome-wide mRNA expression specific to tumor epithelium and tumor stroma in 18 African-American and 17 European-American patients. Numerous genes were differentially expressed between these two patient groups and a two-gene signature in the tumor epithelium distinguished between them. To identify the biological processes in tumors that are different by race/ethnicity, Gene Ontology and disease association analyses were performed. Several biological processes were identified which may contribute to enhanced disease aggressiveness in African-American patients, including angiogenesis and chemotaxis. African-American tumors also contained a prominent interferon signature. The role of angiogenesis in the tumor biology of African-Americans was further investigated by examining the extent of vascularization and macrophage infiltration in an expanded set of 248 breast tumors. Immunohistochemistry revealed that microvessel density and macrophage infiltration is higher in tumors of African-Americans than in tumors of European-Americans. Lastly, using an in silico approach, we explored the potential of tailored treatment options for African-American patients based on their gene expression profile. This exploratory approach generated lists of therapeutics that may have specific antagonistic activity against tumors of African-American patients, e.g., sirolimus, resveratrol, and chlorpromazine in estrogen receptor-negative tumors.
The gene expression profiles of breast tumors indicate that differences in tumor biology may exist between African-American and European-American patients beyond the knowledge of current markers. Notably, pathways related to tumor angiogenesis and chemotaxis could be functionally different in these two patient groups.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Trimethylamine-N-oxide (TMAO) is a compound that is present in seafood and produced through human gut microbial metabolism of its precursors. Previous studies have suggested that elevated TMAO ...concentrations are associated with an increased risk of cardiovascular events. However, the association between diet and TMAO concentrations in free-living adult populations has not been adequately described.
The objective of this study was to identify dietary predictors of plasma TMAO concentrations.
TMAO concentrations were assessed in 2 fasting plasma samples collected 6 mo apart among 620 healthy men. Short-term and long-term dietary intakes were assessed during the same time-frame of blood collections via repeated 7-d dietary records (7DDRs) and a semiquantitative food-frequency questionnaire (SFFQ), respectively. We grouped individual food items into 21 groups and regressed against averaged TMAO concentrations. We also assessed the association between dietary scores and TMAO concentrations.
In models adjusted for demographic characteristics and mutually adjusted for food groups, SFFQ-assessments of fish and egg intakes were significantly associated with increased TMAO concentration (β = 0.082; 95% CI: 0.021, 0.14; P = 0.009 for fish; β = 0.065; 95% CI: 0.004, 0.13; P = 0.039 for egg). The positive association between fish consumption and TMAO concentration was replicated in the 7DDR-assessments (β = 0.12; 95% CI: 0.060, 0.18; P < 0.001). There was no association between red meat intake and TMAO concentrations. The unhealthful plant-based diet index (uPDI) was inversely associated (β = −0.013; 95% CI: −0.021, −0.005; P = 0.001) and healthy dietary scores were positively correlated with TMAO concentration.
TMAO concentration was significantly associated with fish intake, but not with red meat consumption. uPDI, an unhealthy dietary pattern, was inversely related to TMAO concentration. As such, this study suggests that in free-living populations, higher circulating concentrations of TMAO cannot simply be interpreted as a marker of unhealthy food intake or an unhealthy dietary pattern.
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Cancer and organ injury-such as that occurring in the perioperative period, including acute lung injury, myocardial infarction, and acute gut injury-are among the leading causes of death in the ...United States and impose a significant impact on quality of life. MicroRNAs (miRNAs) have been studied extensively during the last two decades for their role as regulators of gene expression, their translational application as diagnostic markers, and their potential as therapeutic targets for disease treatment. Despite promising preclinical outcomes implicating miRNA targets in disease treatment, only a few miRNAs have reached clinical trials. This likely relates to difficulties in the delivery of miRNA drugs to their targets to achieve efficient inhibition or overexpression. Therefore, understanding how to efficiently deliver miRNAs into diseased tissues and specific cell types in patients is critical. This review summarizes current knowledge on various approaches to deliver therapeutic miRNAs or miRNA inhibitors and highlights current progress in miRNA-based disease therapy that has reached clinical trials. Based on ongoing advances in miRNA delivery, we believe that additional therapeutic approaches to modulate miRNA function will soon enter routine medical treatment of human disease, particularly for cancer or perioperative organ injury. SIGNIFICANCE STATEMENT: MicroRNAs have been studied extensively during the last two decades in cancer and organ injury, including acute lung injury, myocardial infarction, and acute gut injury, for their regulation of gene expression, application as diagnostic markers, and therapeutic potentials. In this review, we specifically emphasize the pros and cons of different delivery approaches to modulate microRNAs, as well as the most recent exciting progress in the field of therapeutic targeting of microRNAs for disease treatment in patients.
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