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The discovery of RNAs (for example, messenger RNAs, non-coding RNAs) in sperm has opened the possibility that sperm may function by delivering additional paternal information aside from solely providing the DNA 1 . Increasing evidence now suggests that sperm small non-coding RNAs (sncRNAs) can mediate intergenerational transmission of paternally acquired phenotypes, including mental stress 2 , 3 and metabolic disorders 4 – 6 . How sperm sncRNAs encode paternal information remains unclear, but the mechanism may involve RNA modifications. Here we show that deletion of a mouse tRNA methyltransferase, DNMT2, abolished sperm sncRNA-mediated transmission of high-fat-diet-induced metabolic disorders to offspring. Dnmt2 deletion prevented the elevation of RNA modifications (m 5 C, m 2 G) in sperm 30–40 nt RNA fractions that are induced by a high-fat diet. Also, Dnmt2 deletion altered the sperm small RNA expression profile, including levels of tRNA-derived small RNAs and rRNA-derived small RNAs, which might be essential in composing a sperm RNA ‘coding signature’ that is needed for paternal epigenetic memory. Finally, we show that Dnmt2-mediated m 5 C contributes to the secondary structure and biological properties of sncRNAs, implicating sperm RNA modifications as an additional layer of paternal hereditary information. Zhang et al. report that tRNA methyltransferase Dnmt2 is required for sperm small-non-coding-RNA-mediated transmission of paternal metabolic disorders to the offspring.

Diabetes is far more prevalent in smokers than non-smokers, but the underlying mechanisms of vulnerability are unknown. Here we show that the diabetes-associated gene Tcf7l2 is densely expressed in the medial habenula (mHb) region of the rodent brain, where it regulates the function of nicotinic acetylcholine receptors. Inhibition of TCF7L2 signalling in the mHb increases nicotine intake in mice and rats. Nicotine increases levels of blood glucose by TCF7L2-dependent stimulation of the mHb. Virus-tracing experiments identify a polysynaptic connection from the mHb to the pancreas, and wild-type rats with a history of nicotine consumption show increased circulating levels of glucagon and insulin, and diabetes-like dysregulation of blood glucose homeostasis. By contrast, mutant Tcf7l2 rats are resistant to these actions of nicotine. Our findings suggest that TCF7L2 regulates the stimulatory actions of nicotine on a habenula–pancreas axis that links the addictive properties of nicotine to its diabetes-promoting actions. The transcription factor TCF7L2 mediates two important responses to nicotine in the medial habenula region of the rodent brain: aversion to nicotine, and regulation of blood sugar levels through a polysynaptic habenula–pancreas circuit.

Aim. To study the evolution of impaired fasting glucose (IFG), considering glucose and HbA1c levels and risk factors associated, in a period of 6 years. Methods. We studied 94 subjects with impaired fasting glucose (IFG) that were diagnosed in 2005 and followed up to 2012. Glucose and HbA1c levels were determined. A descriptive analysis of contingence charts was performed in order to study the evolution in the development of type-2 diabetes mellitus (T2DM). Results. Twenty-eight of ninety-four subjects became T2DM; 51/94 remained with IFG; and 20/94 presented normal fasting glucose. From the 28 diabetic subjects, 9 had already developed diabetes and were under treatment with oral hypoglycemic agents; 5 were diagnosed with plasma glucose < 126 mg/dL, but with HbA1c over 6.5%. In those who developed diabetes, 15/28 had a family history of T2DM in first relative degree. Also, diabetic subjects had a BMI significantly higher than nodiabetics (t test: P < 0.01). The individuals that in 2005 had the highest BMI are those who currently have diabetes. Conclusion. The IFG constitutes a condition of high risk of developing T2DM in a few years, especially over 110 mg/dL and in obesity patients.

Isocitrate dehydrogenase 1 and 2 ( IDH1/2 ) mutations and their key effector 2-hydroxyglutarate (2-HG) have been reported to promote oncogenesis in various human cancers. To elucidate molecular mechanism(s) associated with IDH1/2 mutations, we established mouse embryonic fibroblasts (MEF) cells and human colorectal cancer cells stably expressing cancer-associated IDH1 R132C or IDH2 R172S , and analyzed the change in metabolic characteristics of the these cells. We found that IDH1/2 mutants induced intracellular 2-HG accumulation and inhibited cell proliferation. Expression profile analysis by RNA-seq unveiled that glucose transporter 1 (Glut1) was induced by the IDH1/2 mutants or treatment with 2-HG in the MEF cells. Consistently, glucose uptake and lactate production were increased by the mutants, suggesting the deregulation of glucose metabolism. Furthermore, PI3K/Akt/mTOR pathway and Hif1α expression were involved in the up-regulation of Glut1. Together, these results suggest that Glut1 is a potential target regulated by cancer-associated IDH1/2 mutations.

An impaired glucose metabolism, which often leads to the onset of diabetes mellitus (DM), is a common complication of chronic exposure to exogenous and endogenous glucocorticoid (GC) excess and plays an important part in contributing to morbidity and mortality in patients with Cushing syndrome (CS). This article reviews the pathogenesis, epidemiology, diagnosis, and management of changes in glucose metabolism associated with hypercortisolism, addressing both the pathophysiological aspects and the clinical and therapeutic implications. Chronic hypercortisolism may have pleiotropic effects on all major peripheral tissues governing glucose homeostasis. Adding further complexity, both genomic and nongenomic mechanisms are directly induced by GCs in a context-specific and cell-/organ-dependent manner. In this paper, the discussion focuses on established and potential pathologic molecular mechanisms that are induced by chronically excessive circulating levels of GCs and affect glucose homeostasis in various tissues. The management of patients with CS and DM includes treating their hyperglycemia and correcting their GC excess. The effects on glycemic control of various medical therapies for CS are reviewed in this paper. The association between DM and subclinical CS and the role of screening for CS in diabetic patients are also discussed.This article reviews the pathogenesis, epidemiology, diagnosis, and management of glucose metabolism abnormalities associated with hypercortisolism.

Farnesoid X receptors (FXR) are bile acid receptors that play roles in lipid, glucose, and energy homeostasis. Synthetic FXR-specific agonists have been developed for treating nonalcoholic fatty liver disease (NAFLD) patients. However, the detailed mechanism remains unclear. To investigate the effects of FXR on NAFLD and the possible mechanism, FXR-null mice were fed either a normal or a high-fat diet. The FXR-null mice developed hepatomegaly, steatosis, accumulation of lipid droplets in liver cells, glucose metabolism disorder, and elevated serum lipid levels. Transcriptomic results showed increased expression of key lipid synthesis and glucose metabolism-related proteins. We focused on pyruvate dehydrogenase kinase 4 (PDK4), a key enzyme involved in the regulation of glucose and fatty acid (FA) metabolism and homeostasis. Subsequently, we confirmed an increase in PDK4 expression in FXR knockout cells. Moreover, inhibition of PDK4 expression alleviated lipid accumulation in hepatocytes caused by FXR deficiency in vivo and in vitro. Our results identify FXR as a nuclear transcription factor that regulates glucose and lipid metabolism balance through PDK4, providing further insights into the mechanism of FXR agonists in the treatment of metabolic diseases.

Glucose and lipids are important nutrients that provide the majority of energy for each organ to maintain homeostasis of the body. With the continuous improvement in living standards, the incidence of metabolic disorder-associated diseases, such as diabetes, hyperlipidemia, and atherosclerosis, is increasing worldwide. Among them, diabetes, which could be induced by both glucose and lipid metabolic disorders, is one of the five diseases with the highest incidence and mortality worldwide. However, the detailed molecular mechanisms underlying glucose and lipid metabolism disorders and target-organ damage are still not fully defined. MicroRNAs (miRNAs) are small, non-coding, single-stranded RNAs, which usually affect their target mRNAs in the cytoplasm by post-transcriptional regulation. Previously, we have found that miR-320 contributed to glucose and lipid metabolism via different signaling pathways. Most importantly, we identified that nuclear miR-320 mediated diabetes-induced cardiac dysfunction by activating the transcription of fatty acid metabolic genes to cause lipotoxicity in the heart. Here, we reviewed the roles of miR-320 in glucose and lipid metabolism and target-organ damage.

Background The principle of loss of iodine uptake and increased glucose metabolism according to dedifferentiation of thyroid cancer is clinically assessed by imaging. Though these biological properties are widely applied to appropriate iodine therapy, the understanding of the genomic background of this principle is still lacking. We investigated the association between glucose metabolism and differentiation in advanced thyroid cancer as well as papillary thyroid cancer (PTC). Methods We used RNA sequencing of 505 patients with PTC obtained from the Cancer Genome Archives and microarray data of poorly-differentiated and anaplastic thyroid cancer (PDTC/ATC). The signatures of GLUT and glycolysis were estimated to assess glucose metabolic profiles. The glucose metabolic profiles were associated with tumor differentiation score (TDS) and BRAFV600E mutation status. In addition, survival analysis of glucose metabolic profiles was performed for predicting recurrence-free survival. Results In PTC, the glycolysis signature was positively correlated with TDS, while the GLUT signature was inversely correlated with TDS. These correlations were significantly stronger in the BRAFV600E negative group than the positive group. Meanwhile, both GLUT and glycolysis signatures were negatively correlated with TDS in advanced thyroid cancer. The high glycolysis signature was significantly associated with poor prognosis in PTC in spite of high TDS. The glucose metabolic profiles are intricately associated with tumor differentiation in PTC and PDTC/ATC. Conclusions As glycolysis was an independent prognostic marker, we suggest that the glucose metabolism features of thyroid cancer could be another biological progression marker different from differentiation and provide clinical implications for risk stratification. Trial registration Not applicable.

Background Trm10 is a tRNA m1G9 methyltransferase, which in yeast modifies 12 different tRNA species, yet is considered non-essential for viability under standard growth conditions. In humans, there are three Trm10 orthologs, one mitochondrial and two presumed cytoplasmic. A nonsense mutation in one of the cytoplasmic orthologs (TRMT10A) has recently been associated with microcephaly, intellectual disability, short stature and adolescent onset diabetes. Methods and results The subjects were three patients who suffered from microcephaly, intellectual disability, short stature, delayed puberty, seizures and disturbed glucose metabolism, mainly hyperinsulinaemic hypoglycaemia. A homozygous Gly206Arg (G206R) mutation in the TRMT10A gene was identified using whole exome sequencing. The mutation segregated in the family and was absent from large control cohorts. Determination of the methylation activity of the expressed wild-type (WT) and variant TRMT10A enzymes with transcripts of 32P -tRNAGlyGCC as a substrate revealed a striking defect (<0.1% of WT activity) for the variant enzyme. The binding affinity of the G206R variant enzyme to tRNA, determined by fluorescence anisotropy, was similar to that of the WT enzyme. Conclusions The completely abolished m1G9 methyltransferase activity of the mutant enzyme is likely due to significant defects in its ability to bind the methyl donor S-adenosyl methionine. We propose that TRMT10A deficiency accounts for abnormalities in glucose homeostasis initially manifesting both ketotic and non-ketotic hypoglycaemic events with transition to diabetes in adolescence, perhaps as a consequence of accelerated β cell apoptosis. The seizure disorder and intellectual disability are probably secondary to mutant gene expression in neuronal tissue.

Aims/Introduction The aim of the study was to investigate the association of single nucleotide polymorphisms, haplogroups, and copy number in the D‐loop region of mitochondrial DNA (mtDNA) with the genetic susceptibility to gestational diabetes mellitus (GDM) and postpartum abnormal glucose metabolism (AGM). Materials and Methods This was a case–control study in which peripheral blood samples were collected from 500 GDM patients and 500 normal pregnant women from 14 to 20 weeks of pregnancy. The sequence of the D‐loop region of mtDNA was detected by Sanger sequencing, and the copy number of mtDNA was detected by qPCR. Results Analysis of SNPs in the D‐loop region of mtDNA showed that 249d was a risk factor and 309+C and 16193+C were protective factors for GDM. The mtDNA haplogroups R9 and M* were a risk factor and protective factor for GDM, respectively. Compared to the group with normal postpartum glucose tolerance, the haplogroups M7b and N9a were associated with an increased risk of AGM. The whole blood mtDNA copy number was lower in the GDM group than in the control group and was also lower in the postpartum AGM group than in the postpartum normal group. The plasma free mtDNA copy number was higher in the GDM group than in the control group, and higher in the postpartum AGM group than in the normal postpartum group. Conclusions Mitochondrial genomic variants are associated with the risk of GDM and postpartum AGM, and may provide some etiologic evidence for GDM and postpartum AGM. Mitochondrial DNA D‐loop region SNPs, mitochondrial DNA haplogroups, and mitochondrial DNA copy number are risk factors for GDM and postpartum AGM and to provide evidence to better understand the etiology of GDM.