Integrative genomic analyses in adipocytes implicate DNA methylation in human obesity and diabetes

DNA methylation variations are prevalent in human obesity but evidence of a causative role in disease pathogenesis is limited. Here, we combine epigenome-wide association and integrative genomics to investigate the impact of adipocyte DNA methylation variations in human obesity. We discover extensive DNA methylation changes that are robustly associated with obesity (N = 190 samples, 691 loci in subcutaneous and 173 loci in visceral adipocytes, P < 1 × 10-7). We connect obesity-associated methylation variations to transcriptomic changes at >500 target genes, and identify putative methylation-transcription factor interactions. Through Mendelian Randomisation, we infer causal effects of methylation on obesity and obesity-induced metabolic disturbances at 59 independent loci. Targeted methylation sequencing, CRISPR-activation and gene silencing in adipocytes, further identifies regional methylation variations, underlying regulatory elements and novel cellular metabolic effects. Our results indicate DNA methylation is an important determinant of human obesity and its metabolic complications, and reveal mechanisms through which altered methylation may impact adipocyte functions.

MON-LB019 Setmelanotide (RM-493) Reduces Food Intake and Rapidly Induces Weight Loss in a Mouse Model of Alström Syndrome

Introduction&nbsp; Alström&nbsp;syndrome (AS) is an autosomal recessive ciliopathy caused by mutations in&nbsp;ALMS1, which encodes a protein that localizes to centrosomes and basal bodies of primary cilia. Early emergence of obesity in&nbsp;patients with&nbsp;AS suggests a key role for ALMS1 in body weight regulation. Mice with non-functional Alms1 develop normal hypothalamic cilia, but these are not maintained postnatally. This suggests involvement of the central pathways regulating energy balance in the development of obesity in AS. Since leptin signaling has been shown to be impaired in the related ciliopathy Bardet-Biedl syndrome, we hypothesized that targeting central pathways downstream of leptin signaling would reduce food intake and body weight in&nbsp;Alms1-/-&nbsp;mice.&nbsp;&nbsp; Methods&nbsp; Dose-response for the selective melanocortin 1/4 receptor agonist RM-493 (Setmelanotide) in suppressing food intake was determined in 19-wk-old female&nbsp;Alms1-/-&nbsp;mice&nbsp;(n=3) and wild-type (WT) littermates (n=3), individually housed and receiving daily intraperitoneal injections of vehicle (3 d) followed by RM-493 (3 d). A separate cohort of 17-wk-old male (n=4) and female (n=4)&nbsp;Alms1-/-&nbsp;mice had food intake measured continuously in metabolic cages&nbsp;(CLAMS, Columbus Instruments). After determining baseline food intake, mice received vehicle (2 d), followed by RM-493 (3 d), then 3d of washout (no treatment). Repeated measures ANOVA was performed. Mean ± SE and nominal p-values are shown.&nbsp; Results&nbsp; In the dose-response study,&nbsp;Alms-/-&nbsp;and&nbsp;WT&nbsp;had&nbsp;food intake responses that were&nbsp;similar&nbsp;for&nbsp;40&nbsp;(p=0.72),&nbsp;but different&nbsp;for&nbsp;100, 250, and 1000 nmol/kg/d (p’s<0.05). We selected&nbsp;250&nbsp;nmol/kg/d&nbsp;as the dose for further investigation&nbsp;as&nbsp;food intake&nbsp;was unchanged&nbsp;in WT&nbsp;(p=0.23)&nbsp;but reduced&nbsp;in&nbsp;Alms1-/-&nbsp;(p=0.04). In&nbsp;the&nbsp;second cohort,&nbsp;food intake&nbsp;and&nbsp;body weight&nbsp;were&nbsp;similar&nbsp;at&nbsp;baseline&nbsp;compared to&nbsp;vehicle&nbsp;for&nbsp;both&nbsp;male and female&nbsp;Alms1-/-&nbsp;(p’s>0.84).&nbsp;RM-493&nbsp;(250 nmol/kg/d)&nbsp;reduced food intake&nbsp;in male&nbsp;Alms1-/- compared to vehicle (-46.4%;&nbsp;p=0.003), causing&nbsp;a&nbsp;nonsignificant&nbsp;reduction in body weight&nbsp;(-13.1%;&nbsp;p=0.33),&nbsp;whereas&nbsp;food intake&nbsp;in female&nbsp;Alms1-/-&nbsp;was&nbsp;reduced by 28.5%,&nbsp;and body weight by 6.5%,&nbsp;although&nbsp;neither difference was significant (p’s&nbsp;>0.61).&nbsp;During the washout period, male&nbsp;Alms1-/-&nbsp;ate 62.8% more food than during the vehicle period&nbsp;(p<0.0001),&nbsp;resulting in body weight regain&nbsp;of&nbsp;5.0 ± 0.7 g. Female&nbsp;Alms1-/-&nbsp;ate 24.8% more food&nbsp;during the washout period compared to&nbsp;vehicle&nbsp;(p=0.056),&nbsp;regaining&nbsp;2.4 ± 0.6 g of body weight.&nbsp;&nbsp;&nbsp; Conclusion&nbsp; RM-493&nbsp;acutely&nbsp;reduces food intake&nbsp;in&nbsp;Alms1-/-&nbsp;mice&nbsp;with a greater effect in males than females.&nbsp;Withdrawal of RM-493 results in compensatory overeating&nbsp;and&nbsp;rapid weight regain back to pre-treatment values. These findings identify RM-493 as a promising drug&nbsp;candidate&nbsp;for&nbsp;treating&nbsp;obesity in AS.&nbsp;The impact of RM-493 on long-term body weight will be determined in ongoing chronic treatment studies in&nbsp;Alms1-/-&nbsp;and WT mice. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

Disruption of brain-derived neurotrophic factor production from individual promoters generates distinct body composition phenotypes in mice

Brain-derived neurotrophic factor (BDNF) is a key neuropeptide in the central regulation of energy balance. The Bdnf gene contains nine promoters, each producing specific mRNA transcripts that encode a common protein. We sought to assess the phenotypic outcomes of disrupting BDNF production from individual Bdnf promoters. Mice with an intact coding region but selective disruption of BDNF production from Bdnf promoters I, II, IV, or VI (Bdnf-e1^-/-, -e2^-/-, -e4^-/-, and -e6^-/-) were created by inserting an enhanced green fluorescent protein-STOP cassette upstream of the targeted promoter splice donor site. Body composition was measured by MRI weekly from age 4 to 22 wk. Energy expenditure was measured by indirect calorimetry at 18 wk. Food intake was measured in Bdnf-e1^-/- and Bdnf-e2^-/- mice, and pair feeding was conducted. Weight gain, lean mass, fat mass, and percent fat of Bdnf-e1^-/- and Bdnf-e2^-/- mice (both sexes) were significantly increased compared with wild-type littermates. For Bdnf-e4^-/- and Bdnf-e6^-/- mice, obesity was not observed with either chow or high-fat diet. Food intake was increased in Bdnf-e1^-/- and Bdnf-e2^-/- mice, and pair feeding prevented obesity. Mutant and wild-type littermates for each strain (both sexes) had similar total energy expenditure after adjustment for body composition. These findings suggest that the obesity phenotype observed in Bdnf-e1^-/- and Bdnf-e2^-/- mice is attributable to hyperphagia and not altered energy expenditure. Our findings show that disruption of BDNF from specific promoters leads to distinct body composition effects, with disruption from promoters I or II, but not IV or VI, inducing obesity.

Time-restricted feeding of a high-fat diet in male C57BL/6 mice reduces adiposity but does not protect against increased systemic inflammation

Time-restricted feeding (TRF) limits the duration of food availability without altering diet composition and can combat obesity in humans and mice. For this study we evaluated the effect of timing of food access during a TRF protocol on weight gain, adiposity, and inflammation. Young male C57BL/6 mice were placed on a high-fat (HF) diet (45% fat) for 8 weeks. Food access was unrestricted (HF) or restricted to 6 h per day, either for the first half (HF-early) or the second half (HF-late) of the active phase to resemble a window of time for food consumption early or late in the day in a human population. Weight, obesity-associated parameters, and inflammation were measured. TRF reduced weight gain over the 8-week period in mice consuming the same high-fat diet. Consistent with decreased weight gain in the TRF groups, body fat percentage, liver triglycerides, and plasma leptin and cholesterol levels were reduced. Adipose tissue inflammation, measured by CD11b+F4/80+ macrophage infiltration, was reduced in both TRF groups, but systemic tumor necrosis factor-α was increased in all groups consuming the high-fat diet. The HF-late group gained more weight than the HF-early group and had increased insulin resistance, while the HF-early group was protected. Therefore, a TRF protocol is beneficial for weight management when a high-fat diet is consumed, with food consumption earlier in the day showing greater health benefits. However, increased inflammatory markers in the TRF groups suggest that diet components can still increase inflammation even in the absence of overt obesity.

Monounsaturated fatty acid-enriched high-fat diets impede adipose NLRP3 inflammasome-mediated IL-1β secretion and insulin resistance despite obesity

Saturated fatty acid (SFA) high-fat diets (HFDs) enhance interleukin (IL)-1β-mediated adipose inflammation and insulin resistance. However, the mechanisms by which different fatty acids regulate IL-1β and the subsequent effects on adipose tissue biology and insulin sensitivity in vivo remain elusive. We hypothesized that the replacement of SFA for monounsaturated fatty acid (MUFA) in HFDs would reduce pro-IL-1β priming in adipose tissue and attenuate insulin resistance via MUFA-driven AMPK activation. MUFA-HFD-fed mice displayed improved insulin sensitivity coincident with reduced pro-IL-1β priming, attenuated adipose IL-1β secretion, and sustained adipose AMPK activation compared with SFA-HFD-fed mice. Furthermore, MUFA-HFD-fed mice displayed hyperplastic adipose tissue, with enhanced adipogenic potential of the stromal vascular fraction and improved insulin sensitivity. In vitro, we demonstrated that the MUFA oleic acid can impede ATP-induced IL-1β secretion from lipopolysaccharide- and SFA-primed cells in an AMPK-dependent manner. Conversely, in a regression study, switching from SFA- to MUFA-HFD failed to reverse insulin resistance but improved fasting plasma insulin levels. In humans, high-SFA consumers, but not high-MUFA consumers, displayed reduced insulin sensitivity with elevated pycard-1 and caspase-1 expression in adipose tissue. These novel findings suggest that dietary MUFA can attenuate IL-1β-mediated insulin resistance and adipose dysfunction despite obesity via the preservation of AMPK activity.

Protein quality and the protein to carbohydrate ratio within a high fat diet influences energy balance and the gut microbiota in C57BL/6J mice

Macronutrient quality and composition are important determinants of energy balance and the gut microbiota. Here, we investigated how changes to protein quality (casein versus whey protein isolate; WPI) and the protein to carbohydrate (P/C) ratio within a high fat diet (HFD) impacts on these parameters. Mice were fed a low fat diet (10% kJ) or a high fat diet (HFD; 45% kJ) for 21 weeks with either casein (20% kJ, HFD) or WPI at 20%, 30% or 40% kJ. In comparison to casein, WPI at a similar energy content normalised energy intake, increased lean mass and caused a trend towards a reduction in fat mass (P = 0.08), but the protein challenge did not alter oxygen consumption or locomotor activity. WPI reduced HFD-induced plasma leptin and liver triacylglycerol, and partially attenuated the reduction in adipose FASN mRNA in HFD-fed mice. High throughput sequence-based analysis of faecal microbial populations revealed microbiota in the HFD-20% WPI group clustering closely with HFD controls, although WPI specifically increased Lactobacillaceae/Lactobacillus and decreased Clostridiaceae/Clostridium in HFD-fed mice. There was no effect of increasing the P/C ratio on energy intake, but the highest ratio reduced HFD-induced weight gain, fat mass and plasma triacylglycerol, non-esterified fatty acids, glucose and leptin levels, while it increased lean mass and oxygen consumption. Similar effects were observed on adipose mRNA expression, where the highest ratio reduced HFD-associated expression of UCP-2, TNFα and CD68 and increased the diet-associated expression of β3-AR, LPL, IR, IRS-1 and GLUT4. The P/C ratio also impacted on gut microbiota, with populations in the 30/40% WPI groups clustering together and away from the 20% WPI group. Taken together, our data show that increasing the P/C ratio has a dramatic effect on energy balance and the composition of gut microbiota, which is distinct from that caused by changes to protein quality.

Impact of leucine on energy balance

Body weight is determined by the balance between energy intake and energy expenditure. When energy intake exceeds energy expenditure, the surplus energy is stored as fat in the adipose tissue, which causes its expansion and may even lead to the development of obesity. Thus, there is a growing interest to develop dietary interventions that could reduce the current obesity epidemic. In this regard, data from a number of in vivo and in vitro studies suggest that the branched-chain amino acid leucine influences energy balance. However, this has not been consistently reported. Here, we review the literature related to the effects of leucine on energy intake, energy expenditure and lipid metabolism as well as its effects on the cellular activity in the brain (hypothalamus) and in peripheral tissues (gastro-intestinal tract, adipose tissue, liver and muscle) regulating the above physiological processes. Moreover, we discuss how obesity may influence the actions of this amino acid.

Mesolithic and later sites around the Inner Sound, Scotland the work of the Scotland's First Settlers project 1998-2004

Scotland's First Settlers comprised a survey project to locate and examine sites relating to the earliest, Mesolithic, settlement of the Inner Sound, along the coastlands between Skye and the west coast of Scotland. Particular foci of interest included the existence and nature of midden sites, the use of rockshelters and caves, and the different types of lithic raw material in use. In addition, information relating to the human use of the area up to the present day was recorded. Fieldwork took place over five years between 1999 and 2004: the entire coastline of the Inner Sound together with its islands was walked; 129 new archaeological sites were recorded; 36 sites were shovel pitted; 44 test pitted; and one major excavation took place. Excavation at Sand has been particularly exciting as it has resulted in the analysis of a shell midden dating to the early-mid seventh millennium BC, the early Mesolithic of Scotland. This report comprises the results of survey and excavation work as well as detailed artefact reports, full information on ecofacts such as shell, and bone, and information on the development of the landscape and environment, including sea level change. Finally, the broad-scale coverage of the project has led to a number of discussion points that have much to offer further work, both within the area and further afield. Digital material associated with this project is available through Archaeology Data Service archive http://dx.doi.org/10.5284/1000285 Scotland's First Settlers

Clinical evaluation of a glass ionomer cement in primary molars

PURPOSE

The aim of the study was to evaluate the clinical performance of a high powder:liquid ratio self-cure glass ionomer cement in the restoration of primary molars.

METHODS

Fuji IX GP (GC International, Tokyo, Japan) was used to restore 129 carious cavities (56 1-surface; 73 2-surface) in 69 patients of mean age 6 y 7 mo. Approximal cavities were prepared with a slot only design, and all cavities were small to medium in size. Restorations were evaluated at 6 mo, 1 y and 2 y using USPHS criteria, and the survival rate calculated using survival analysis.

RESULTS

The cumulative survival rate of single-surface restorations was 100 percent at 2 y, and of 2-surface restorations was 99 percent at 6 months and 1 year, and 93 percent at 2 y. All failures were due to loss of restoration. The overall USPHS alfa ratings at 2 y were: marginal discoloration, 96 percent; anatomic form, 100 percent; marginal adaptation, 99 percent. There was no incidence of secondary caries.

CONCLUSIONS

A high powder:liquid ratio glass ionomer cement was successful over 2 years in the restoration of small-medium sized cavities in primary teeth. It is predictable that the performance will continue to be highly satisfactory over the next 2-3 years.