mRNA GPR162 changes are associated with decreased food intake in rat, and its human genetic variants with impairments in glucose homeostasis in two Swedish cohorts.

G protein-coupled receptors (GPCRs) are a class of integral membrane proteins mediating intercellular interactions of fundamental physiological importance for survival including regulation of food intake, blood pressure, and hormonal sensing signaling, among other roles. Homeostatic alterations in the physiological status of GPCRs are often associated with underlying causes of disease, and to date, several orphan GPCRs are still uncharacterized. Findings from our previous study demonstrate that the Rhodopsin family protein GPR162 is widely expressed in GABAergic as well as other neurons within the mouse hippocampus, whereas extensive expression is observed in hypothalamus, amygdala, and ventral tegmental area, regions strictly interconnected and involved in the regulation of energy homeostasis and hedonic feeding.

Determination of obesity associated gene variants related to TMEM18 through ultra-deep targeted re-sequencing in a case-control cohort for pediatric obesity.

Genome-wide association studies (GWAS) have revealed association of a locus approximately 25b downstream of the TMEM18 gene with body mass and obesity. We utilized targeted re-sequencing of the body mass associated locus in proximity of TMEM18 in a case-control population of severely obese children and adolescents from the Stockholm area. We expanded our study to include the TMEM18 gene itself, with the aim of identifying body mass associated genetic variants.

Obsessive-compulsivity and working memory are associated with differential prefrontal cortex and insula activation in adolescents with a recent diagnosis of an eating disorder.

The role of rumination at the beginning of eating disorder (ED) is not well understood. We hypothesised that impulsivity, rumination and restriction could be associated with neural activity in response to food stimuli in young individuals with eating disorders (ED). We measured neural responses with functional magnetic resonance imaging (fMRI), tested working memory (WM) and administered the eating disorders examination questionnaire (EDE-Q), Barratt impulsivity scale (BIS-11) and obsessive-compulsive inventory (OCI-R) in 15 adolescent females with eating disorder not otherwise specified (EDNOS) (mean age 15 years) and 20 age-matched healthy control females.

Associations of self-reported sleep disturbance and duration with academic failure in community-dwelling Swedish adolescents: sleep and academic performance at school.

Objective: To examine associations of self-reported sleep disturbance and short sleep duration with the risk for academic failure.

Methods: A cohort of ~40,000 adolescents (age range: 12-19 years) who were attending high school grades 7, 9, and 2nd year of upper secondary school in the Swedish Uppsala County were invited to participate in the Life and Health Young Survey (conducted between 2005 and 2011 in Uppsala County, Sweden). In addition to the question how many subjects they failed during the school year (outcome variable), subsamples of adolescents also answered questions related to subjective sleep disturbance (n = 20,026) and habitual sleep duration (n = 4736) (exposure variables).

Genome-wide analysis reveals DNA methylation markers that vary with both age and obesity.

The combination of the obesity epidemic and an aging population presents growing challenges for the healthcare system. Obesity and aging are major risk factors for a diverse number of diseases and it is of importance to understand their interaction and the underlying molecular mechanisms. Herein the authors examined the methylation levels of 27578 CpG sites in 46 samples from adult peripheral blood.

BDNF polymorphisms are linked to poorer working memory performance, reduced cerebellar and hippocampal volumes and differences in prefrontal cortex in a Swedish elderly population.

Background: Brain-derived neurotrophic factor (BDNF) links learning, memory and cognitive decline in elderly, but evidence linking BDNF allele variation, cognition and brain structural differences is lacking.

Methods: 367 elderly Swedish men (n = 181) and women (n = 186) from Prospective Investigation of the Vasculature in Uppsala seniors (PIVUS) were genotyped and the BDNF functional rs6265 SNP was further examined in subjects who completed the Trail Making Task (TMT), verbal fluency task, and had a magnetic resonance imaging (MRI) scan. Voxel-based morphometry (VBM) examined brain structure, cognition and links with BDNF.

Involvement of the neutral amino acid transporter SLC6A15 and leucine in obesity-related phenotypes.

Brain pathways, including those in hypothalamus and nucleus of the solitary tract, influence food intake, nutrient preferences, metabolism and development of obesity in ways that often differ between males and females. Branched chain amino acids, including leucine, can suppress food intake, alter metabolism and change vulnerability to obesity. The SLC6A15 (v7-3) gene encodes a sodium-dependent transporter of leucine and other branched chain amino acids that is expressed by neurons in hypothalamus and nucleus of the solitary tract.

Polymorphisms in FTO and near TMEM18 associate with type 2 diabetes and predispose to younger age at diagnosis of diabetes.

Variations in the FTO gene and near the TMEM18 gene are risk factors for common form of obesity, but have also been linked with type 2 diabetes (T2D). Our aim was to investigate the contribution of these variants to risk of T2D in a population in Latvia. Four single nucleotide polymorphisms (SNP) in the first and fourth intronic regions of FTO and one close to TMEM18 were genotyped in 987 patients with T2D and 1080 controls selected from the Latvian Genome Data Base (LGDB).

The MAP2K5-linked SNP rs2241423 is associated with BMI and obesity in two cohorts of Swedish and Greek children.

Background: Recent genome-wide association studies have identified a single nucleotide polymorphism within the last intron of MAP2K5 associated with a higher body mass index (BMI) in adults. MAP2K5 is a component of the MAPK-family intracellular signaling pathways, responding to extracellular growth factors such as brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF). In this study, we examined the association of this variant in two cohorts of children from Sweden and Greece.

Neurobeachin, a regulator of synaptic protein targeting, is associated with body fat mass and feeding behavior in mice and body-mass index in humans.

Neurobeachin (Nbea) regulates neuronal membrane protein trafficking and is required for the development and functioning of central and neuromuscular synapses. In homozygous knockout (KO) mice, Nbea deficiency causes perinatal death. Here, we report that heterozygous KO mice haploinsufficient for Nbea have higher body weight due to increased adipose tissue mass.

Genome wide analysis reveals association of a FTO gene variant with epigenetic changes.

Variants of the FTO gene show strong association with obesity, but the mechanisms behind this association remain unclear. We determined the genome wide DNA methylation profile in blood from 47 female preadolescents. We identified sites associated with the genes KARS, TERF2IP, DEXI, MSI1, STON1 and BCAS3 that had a significant differential methylation level in the carriers of the FTO risk allele (rs9939609).

Association of TMEM18 variants with BMI and waist circumference in children and correlation of mRNA expression in the PFC with body weight in rats.

Genome-wide association studies have shown a strong association of single-nucleotide polymorphisms (SNPs) in the near vicinity of the TMEM18 gene. The effects of the TMEM18-associated variants are more readily observed in children. TMEM18 encodes a 3TM protein, which locates to the nuclear membrane.

Detailed analysis of variants in FTO in association with body composition in a cohort of 70-year-olds suggests a weakened effect among elderly.

Background: The rs9939609 single-nucleotide polymorphism (SNP) in the fat mass and obesity (FTO) gene has previously been associated with higher BMI levels in children and young adults. In contrast, this association was not found in elderly men. BMI is a measure of overweight in relation to the individuals' height, but offers no insight into the regional body fat composition or distribution.

The fat mass and obesity gene is linked to reduced verbal fluency in overweight and obese elderly men.

Humans carrying the prevalent rs9939609 A allele of the fat mass and obesity-associated (FTO) gene are more susceptible to developing obesity than noncarries. Recently, polymorphisms in the FTO gene of elderly subjects have also been linked to a reduced volume in the frontal lobe as well as increased risk for incident Alzheimer disease. However, so far there is no evidence directly linking the FTO gene to functional cognitive processes.

The obesity gene, TMEM18, is of ancient origin, found in majority of neuronal cells in all major brain regions and associated with obesity in severely obese children.

Background: TMEM18 is a hypothalamic gene that has recently been linked to obesity and BMI in genome wide association studies. However, the functional properties of TMEM18 are obscure.

Methods: The evolutionary history of TMEM18 was inferred using phylogenetic and bioinformatic methods.

The common FTO variant rs9939609 is not associated with BMI in a longitudinal study on a cohort of Swedish men born 1920-1924.

Background: Common FTO (fat mass and obesity associated) gene variants have recently been strongly associated with body mass index and obesity in several large studies. Here we set out to examine the association of the FTO variant rs9939609 with BMI in a 32 year follow up study of men born 1920-1924. Moreover, we analyzed the effect of physical activity on the different genotypes.

C6ORF192 forms a unique evolutionary branch among solute carriers (SLC16, SLC17, and SLC18) and is abundantly expressed in several brain regions.

About one third of all known human proteins are membrane proteins, which constitute several large families. The solute carriers with over 300 known members are probably the second largest family with additional members frequently being identified. We recently found a new putative solute carrier, C6ORF192, belonging to the major facilitator superfamily type of proteins.

The evolutionary history and tissue mapping of amino acid transporters belonging to solute carrier families SLC32, SLC36, and SLC38.

Members of the solute carrier families (SLC) 32, 36, and 38, together also designated the beta-group of SLCs, are known to transport neutral amino acids. In this paper, we show that these three families were present before the split of the animal lineage and that they are likely to share a common decent. We also show that the APF transporters found in plants are most likely homologous to the mammalian beta-group, suggesting that this type of transporters arouse early in the evolution of eukaryotes.

Major gender difference in association of FTO gene variant among severely obese children with obesity and obesity related phenotypes.

Recent studies have shown that SNPs in the FTO gene predispose to childhood and adult obesity. In this study, we examined the association between variants in FTO and KIAA1005, a gene that maps closely to FTO, and obesity, as well as obesity related traits among 450 well characterised severely obese children and 512 normal weight controls. FTO showed significant association with several obesity related traits while SNPs in KIAA1005 did not.

The obesity gene, FTO, is of ancient origin, up-regulated during food deprivation and expressed in neurons of feeding-related nuclei of the brain.

Gene variants of the FTO (fatso) gene have recently been strongly associated with body mass index and obesity. The FTO gene is well conserved and found in a single copy in vertebrate species including fish and chicken, suggesting that the ancestor of this gene was present 450 million years ago. Surprisingly, the FTO gene is present in two species of algae but not in any other invertebrate species.

Allelotyping by massively parallel pyrosequencing of SNP-carrying trinucleotide threads.

Here we present an approach for allelotyping combining the multiplexing features of the trinucleotide threading (TnT) method with pooling of genomic DNA and massively parallel pyrosequencing, enabling reliable allele frequency estimation in large cohorts. The approach offers several benefits as compared to array-based methods and allows undertaking highly complex studies without compromising accuracy, while keeping the workload to a minimum. This proof-of-concept study involves formation of trinucleotide threads, targeting a total of 147 single-nucleotide polymorphisms (SNPs) related to obesity and cancer, for multiplex amplification and allele extraction from a pool of 462 genomes, followed by massively parallel pyrosequencing.

Identification of six putative human transporters with structural similarity to the drug transporter SLC22 family.

The solute carrier family 22 (SLC22) is a large family of organic cation and anion transporters. These are transmembrane proteins expressed predominantly in kidneys and liver and mediate the uptake and excretion of environmental toxins, endogenous substances, and drugs from the body. Through a comprehensive database search we identified six human proteins not yet cloned or annotated in the reference sequence databases.