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1.
Article in English | MEDLINE | ID: mdl-38967296

ABSTRACT

OBJECTIVE: The objective of this study was to identify the transcriptional landscape of insulin resistance (IR) in subcutaneous adipose tissue (SAT) in humans across the spectrum of obesity. METHODS: We used SAT RNA sequencing in 220 individuals with metabolic phenotyping. RESULTS: We identified a 35-gene signature with high predictive accuracy for homeostatic model of IR that was expressed across a variety of non-immune cell populations. We observed primarily "protective" IR associations for adipocyte transcripts and "deleterious" associations for macrophage transcripts, as well as a high concordance between SAT and visceral adipose tissue (VAT). Multiple SAT genes exhibited dynamic expression 5 years after weight loss surgery and with insulin stimulation. Using available expression quantitative trait loci in SAT and/or VAT, we demonstrated similar genetic effect sizes of SAT and VAT on type 2 diabetes and BMI. CONCLUSIONS: SAT is conventionally viewed as a metabolic buffer for lipid deposition during positive energy balance, whereas VAT is viewed as a dominant contributor to and prime mediator of IR and cardiometabolic disease risk. Our results implicate a dynamic transcriptional architecture of IR that resides in both immune and non-immune populations in SAT and is shared with VAT, nuancing the current VAT-centric concept of IR in humans.

2.
Arterioscler Thromb Vasc Biol ; 43(6): 1054-1065, 2023 06.
Article in English | MEDLINE | ID: mdl-37051928

ABSTRACT

BACKGROUND: Adipose tissue insulin resistance is linked to altered plasma levels of triglycerides and HDL (high-density lipoprotein)-cholesterol. However, its degree of independence from liver resistance and different metabolic traits (lipolysis, lipogenesis) effected is not clear and was presently investigated. METHODS: In 3290 adult subjects, plasma levels of triglycerides and HDL-cholesterol were cross-sectionally measured and related to interindividual variations in measures of insulin resistance in the liver (homeostasis mode assessment of insulin resistance index) or adipose tissue (Adipo-IR index). In subgroups, insulin-induced antilipolysis and lipogenesis in isolated subcutaneous fat cells (n=578) were determined alongside global adipose tissue gene expression (n=132). RESULTS: Using linear regression, homeostasis mode assessment of insulin resistance and Adipo-IR strongly correlated with the plasma lipids explaining 33% of the variations in triglycerides. Together with other variables (age, sex, body mass index, cardiometabolic disorders, nicotine use, ethnicity, and physical activity) in multiple regression, homeostasis mode assessment of insulin resistance, and Adipo-IR each remained an important regressor for triglycerides and HDL-cholesterol (P<0.0001). In fat cells, half-maximum effective concentration but not maximum effect of insulin on antilipolysis and lipogenesis contributed independently to variations in triglycerides and HDL-cholesterol (P=0.001 or lower). This was linked to expression of the insulin receptor, insulin receptor substrate-1, and AKT serine/threonine kinase 2 in adipose tissue. CONCLUSIONS: Markers of insulin resistance in the liver and adipose tissue each associate strongly, and independently of each other, to elevated triglycerides and decreased HDL levels. At the fat cell, early insulin receptor signaling and sensitivity, but not maximum insulin action contributes to the variations in circulating triglycerides and HDL-cholesterol.


Subject(s)
Dyslipidemias , Insulin Resistance , Adult , Humans , Receptor, Insulin , Obesity/metabolism , Adipose Tissue/metabolism , Triglycerides , Insulin , Cholesterol, HDL , Liver/metabolism , Dyslipidemias/diagnosis , Dyslipidemias/genetics
4.
United European Gastroenterol J ; 11(1): 79-91, 2023 02.
Article in English | MEDLINE | ID: mdl-36454055

ABSTRACT

BACKGROUND: Post-pancreatitis diabetes mellitus (PPDM) is a common consequence of chronic pancreatitis (CP). We aimed to determine the incidence and predictors of PPDM after CP onset, as well as complications and antidiabetic therapy requirements, in a high-volume tertiary center. METHODS: We did a cohort study with retrospectively collected data from patients with definite CP seen at the Karolinska University Hospital between January 1999 and December 2020. Cause-specific Cox regression analysis was used to assess PPDM predictors. To estimate risk of complications and need for therapy the Fine-Gray subdistribution hazard model was employed, accounting for death as a competing risk. RESULTS: We identified 481 patients with CP. The cumulative incidence of PPDM was 5.1%, 13.2%, 27.5% and 38.9% at 5, 10, 15 and 20 years, respectively. Compared to CP patients without diabetes, patients with PPDM were predominantly male (55% vs. 75%), had more frequently alcoholic etiology (44% vs. 62%) and previous acute pancreatitis. The only independent predictor of PPDM was presence of pancreatic calcifications (aHR = 2.45, 95% CI 1.30-4.63). Patients with PPDM had higher rates of microangiopathy (aSHR = 1.59, 95% CI 1.02-2.52) and infection (aSHR = 4.53, 95% CI 2.60-9.09) compared to CP patients who had type 2 diabetes (T2DM). The rate of insulin use was three-fold higher, whereas metformin use rate was two-fold higher in the same comparison. CONCLUSIONS: Patients with PPDM have a higher frequency of clinically significant complications and were more commonly prescribed insulin and metformin, suggesting a more aggressive phenotype than that of T2DM. Greater PPDM awareness is needed to optimize disease management.


Subject(s)
Diabetes Mellitus, Type 2 , Insulins , Metformin , Pancreatitis, Chronic , Male , Female , Humans , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/epidemiology , Cohort Studies , Retrospective Studies , Acute Disease , Pancreatitis, Chronic/complications , Pancreatitis, Chronic/diagnosis , Pancreatitis, Chronic/epidemiology , Metformin/therapeutic use
5.
Diabetes ; 72(3): 316-325, 2023 03 01.
Article in English | MEDLINE | ID: mdl-36445942

ABSTRACT

Sedentary people have insulin resistance in their skeletal muscle, but whether this also occurs in fat cells was unknown. Insulin inhibition of hydrolysis of triglycerides (antilipolysis) and stimulation of triglyceride formation (lipogenesis) were investigated in subcutaneous fat cells from 204 sedentary and 336 physically active subjects. Insulin responsiveness (maximum hormone effect) and sensitivity (half-maximal effective concentration) were determined. In 69 women, hyperinsulinemia-induced circulating fatty acid levels were measured. In 128 women, adipose gene expression was analyzed. Responsiveness of insulin for antilipolysis (60% inhibition) and lipogenesis (twofold stimulation) were similar between sedentary and active subjects. Sensitivity for both measures decreased ˜10-fold in sedentary subjects (P < 0.01). However, upon multiple regression analysis, only the association between antilipolysis sensitivity and physical activity remained significant when adjusting for BMI, age, sex, waist-to-hip ratio, fat-cell size, and cardiometabolic disorders. Fatty acid levels decreased following hyperinsulinemia but remained higher in sedentary compared with active women (P = 0.01). mRNA expression of insulin receptor and its substrates 1 and 2 was decreased in sedentary subjects. In conclusion, while the maximum effect is preserved, sensitivity to insulin's antilipolytic effect in subcutaneous fat cells is selectively lower in sedentary subjects.


Subject(s)
Hyperinsulinism , Insulin Resistance , Humans , Female , Insulin Resistance/physiology , Blood Glucose/metabolism , Sedentary Behavior , Obesity/metabolism , Insulin/metabolism , Hyperinsulinism/metabolism , Fatty Acids/metabolism , Adipose Tissue/metabolism
6.
J Clin Med ; 11(13)2022 Jun 28.
Article in English | MEDLINE | ID: mdl-35807009

ABSTRACT

BACKGROUND: Autoimmune pancreatitis (AIP) is a specific form of chronic pancreatitis with a high relapse rate after treatment. AIP patients are burdened with an increased risk of long-term sequelae such as exocrine and endocrine insufficiency. Our objective was to investigate if pharmacological treatment affects both endocrine and exocrine pancreatic function in patients with AIP. METHODS: We included 59 patients with definite AIP in the final analysis. Screening for diabetes mellitus (DM) and pancreatic exocrine insufficiency (PEI) was performed at the time of AIP diagnosis and during follow-up. RESULTS: There were 40 (67.8%) males and 19 (32.2%) females; median age at diagnosis was 65 years. Median follow-up after the diagnosis of AIP was 62 months. PEI prevalence at diagnosis was 72.7% and was 63.5% at follow-up. The cumulative incidence of DM was 17.9%, with a prevalence of DM at diagnosis of 32.8%. No strong association was found between pharmacological treatment and occurrence of PEI and DM. Univariate analysis identified potential risk factors for PEI (other organ involvement and biliary stenting) and for DM (overweight, blue-collar profession, smoking, weight loss or obstructive jaundice as presenting symptoms, imaging showing diffuse pancreatic enlargement, smoking). In a multivariate analysis, only obstructive jaundice was identified as a risk factor for DM both at diagnosis and during follow-up. CONCLUSIONS: Our results suggest that the prevalence of endocrine and exocrine insufficiency in AIP is high at diagnosis with an additional risk of PEI and DM during follow-up despite pharmacological treatment.

7.
Nat Commun ; 13(1): 2958, 2022 05 26.
Article in English | MEDLINE | ID: mdl-35618718

ABSTRACT

The pleiotropic function of long noncoding RNAs is well recognized, but their direct role in governing metabolic homeostasis is less understood. Here, we describe a human adipocyte-specific lncRNA, ADIPINT, that regulates pyruvate carboxylase, a pivotal enzyme in energy metabolism. We developed an approach, Targeted RNA-protein identification using Orthogonal Organic Phase Separation, which identifies that ADIPINT binds to pyruvate carboxylase and validated the interaction with electron microscopy. ADIPINT knockdown alters the interactome and decreases the abundance and enzymatic activity of pyruvate carboxylase in the mitochondria. Reduced ADIPINT or pyruvate carboxylase expression lowers adipocyte lipid synthesis, breakdown, and lipid content. In human white adipose tissue, ADIPINT expression is increased in obesity and linked to fat cell size, adipose insulin resistance, and pyruvate carboxylase activity. Thus, we identify ADIPINT as a regulator of lipid metabolism in human white adipocytes, which at least in part is mediated through its interaction with pyruvate carboxylase.


Subject(s)
Pyruvate Carboxylase , RNA, Long Noncoding , Adipocytes, White/metabolism , Adipose Tissue/metabolism , Humans , Lipids , Pyruvate Carboxylase/genetics , Pyruvate Carboxylase/metabolism , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism
8.
Sci Rep ; 12(1): 3666, 2022 03 07.
Article in English | MEDLINE | ID: mdl-35256633

ABSTRACT

Total body fat and central fat distribution are heritable traits and well-established predictors of adverse metabolic outcomes. Lipolysis is the process responsible for the hydrolysis of triacylglycerols stored in adipocytes. To increase our understanding of the genetic regulation of body fat distribution and total body fat, we set out to determine if genetic variants associated with body mass index (BMI) or waist-hip-ratio adjusted for BMI (WHRadjBMI) in genome-wide association studies (GWAS) mediate their effect by influencing adipocyte lipolysis. We utilized data from the recent GWAS of spontaneous and isoprenaline-stimulated lipolysis in the unique GENetics of Adipocyte Lipolysis (GENiAL) cohort. GENiAL consists of 939 participants who have undergone abdominal subcutaneous adipose biopsy for the determination of spontaneous and isoprenaline-stimulated lipolysis in adipocytes. We report 11 BMI and 15 WHRadjBMI loci with SNPs displaying nominal association with lipolysis and allele-dependent gene expression in adipose tissue according to in silico analysis. Functional evaluation of candidate genes in these loci by small interfering RNAs (siRNA)-mediated knock-down in adipose-derived stem cells identified ZNF436 and NUP85 as intrinsic regulators of lipolysis consistent with the associations observed in the clinical cohorts. Furthermore, candidate genes in another BMI-locus (STX17) and two more WHRadjBMI loci (NID2, GGA3, GRB2) control lipolysis alone, or in conjunction with lipid storage, and may hereby be involved in genetic control of body fat. The findings expand our understanding of how genetic variants mediate their impact on the complex traits of fat storage and distribution.


Subject(s)
Genome-Wide Association Study , Lipolysis , Adipocytes/metabolism , Adipose Tissue/metabolism , Genetic Loci , Humans , Isoproterenol/metabolism , Lipolysis/genetics , Transcription Factors/metabolism
9.
Diabetes ; 71(6): 1350-1362, 2022 06 01.
Article in English | MEDLINE | ID: mdl-35320353

ABSTRACT

Interindividual differences in generation of new fat cells determine body fat and type 2 diabetes risk. In the GENetics of Adipocyte Lipolysis (GENiAL) cohort, which consists of participants who have undergone abdominal adipose biopsy, we performed a genome-wide association study (GWAS) of fat cell number (n = 896). Candidate genes from the genetic study were knocked down by siRNA in human adipose-derived stem cells. We report 318 single nucleotide polymorphisms (SNPs) and 17 genetic loci displaying suggestive (P < 1 × 10-5) association with fat cell number. Two loci pass threshold for GWAS significance, on chromosomes 2 (lead SNP rs149660479-G) and 7 (rs147389390-deletion). We filtered for fat cell number-associated SNPs (P < 1.00 × 10-5) using evidence of genotype-specific expression. Where this was observed we selected genes for follow-up investigation and hereby identified SPATS2L and KCTD18 as regulators of cell proliferation consistent with the genetic data. Furthermore, 30 reported type 2 diabetes-associated SNPs displayed nominal and consistent associations with fat cell number. In functional follow-up of candidate genes, RPL8, HSD17B12, and PEPD were identified as displaying effects on cell proliferation consistent with genetic association and gene expression findings. In conclusion, findings presented herein identify SPATS2L, KCTD18, RPL8, HSD17B12, and PEPD of potential importance in controlling fat cell numbers (plasticity), the size of body fat, and diabetes risk.


Subject(s)
Diabetes Mellitus, Type 2 , Genome-Wide Association Study , Adipocytes/metabolism , Adipose Tissue/metabolism , Cell Count , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/metabolism , Genetic Loci , Humans , Polymorphism, Single Nucleotide
10.
Surg Obes Relat Dis ; 18(6): 683-692, 2022 06.
Article in English | MEDLINE | ID: mdl-35337765

ABSTRACT

BACKGROUND: There are few long-term mechanistic studies in adipose tissue that investigate the metabolic effects of bariatric surgery. Changes in lipogenesis may be involved in long-term weight development. OBJECTIVES: To investigate the long-term effect of bariatric surgery on lipogenesis in abdominal fat cells and whether surgical treatment could induce an epigenetic memory that would maintain improved lipogenesis in spite of body weight relapse. SETTING: Karolinska University Hospital in Stockholm County, Sweden. METHODS: A total of 22 women with obesity living in the Stockholm area were examined before, 2, 5, and 10 years after bariatric surgery. Abdominal adipose tissue biopsies were obtained. Fat cells were isolated and spontaneous and insulin stimulated glucose incorporation into lipids were assayed. CpG-methylation profiling was performed on adipocytes using the Infinium EPIC BeadChips. RESULTS: Bariatric surgery was associated with improvement in adipocyte spontaneous and insulin stimulated lipogenesis, which was maintained despite some later weight regain (29 % of initial weight loss). There was also an increase in fat cell size between 2- and 10-year follow-up, albeit not to presurgery levels. There were 7729 differentially methylated CpG sites (DMS) at 2 years that showed no sign of return to baseline at either 5 or 10 years. Merging results with expression profiles identified 1259 genes with DMS which showed early response or continual change in expression in one direction after surgery. Upregulated genes with DMS were enriched in gene sets linked to cellular response to insulin stimulus (e.g., IRS1, IRS2, PDE3B, and AKT2) and regulation of lipid metabolic processes. CONCLUSION: Bariatric surgery leads to long-term improvement of lipogenesis and insulin responsiveness in subcutaneous adipocytes in women in spite of some partial body weight regain postoperatively. This may to some extent be explained by epigenetic modifications of fat cell function.


Subject(s)
Bariatric Surgery , Adipocytes/pathology , Cohort Studies , Female , Humans , Insulin/metabolism , Longitudinal Studies , Recurrence , Weight Gain , Weight Loss
11.
Nutrients ; 13(7)2021 Jul 13.
Article in English | MEDLINE | ID: mdl-34371899

ABSTRACT

Introduction: Chronic pancreatitis (CP) can lead to malnutrition, an established risk factor for low bone mineral density (BMD) and fractures. This study aims to determine the prevalence of low BMD, assess fracture incidence and explore risk factors for fractures in patients with CP. Patients and methods: We performed a retrospective analysis of all patients treated for CP at Karolinska University Hospital between January 1999 and December 2020. Electronic medical records were retrieved to assess demographic, laboratory and clinical data. Patients subjected to dual-energy X-ray absorptiometry (DXA) were categorised as either low BMD or normal BMD. We investigated whether the rate of fractures, defined by chart review, differed between these groups using Cox regression, adjusting the model for age, sex and body mass index (BMI). Additional within-group survival analysis was conducted to identify potential risk factors. Results: DXA was performed in 23% of patients with definite CP. Some 118 patients were included in the final analysis. Low BMD was present in 63 (53.4%) patients. Mean age at CP diagnosis in the total cohort was 53.1 years and was significantly lower in patients with normal BMD than in patients with low BMD (45.5 vs. 59.8, p < 0.001). Significant differences were observed in smoking status and disease aetiology, i.e., a higher proportion of patients with low BMD were current or former smokers, with nicotine or alcohol being a more common cause of CP (p < 0.05). Total follow-up time was 898 person-years. Fractures were found in 33 (28.0%) patients: in 5 of 55 patients (16.7%) with normal DXA and in 28 of 63 patients (44.4%) with low BMD (adjusted hazard ratio = 3.4, 95% confidence interval (CI) = 1.2-9.6). Patients with at least 3 months of consecutive pancreatic enzyme replacement therapy (PERT) or vitamin D treatment had a longer median time to fracture after CP diagnosis. Conclusion: DXA was only performed in 23% of patients with definite CP in this study, indicating a low adherence to current European guidelines. A low BMD was found in 53.4% of patients with CP, and 44% of the patients with a low BMD experienced a fracture during follow-up. Moreover, the fracture rate in patients with low BMD increased compared to those with normal BMD.


Subject(s)
Bone Density , Exocrine Pancreatic Insufficiency/epidemiology , Osteoporosis/epidemiology , Osteoporotic Fractures/epidemiology , Pancreatitis, Chronic/epidemiology , Absorptiometry, Photon , Adult , Aged , Exocrine Pancreatic Insufficiency/diagnostic imaging , Exocrine Pancreatic Insufficiency/physiopathology , Female , Humans , Incidence , Male , Middle Aged , Osteoporosis/diagnostic imaging , Osteoporosis/physiopathology , Osteoporotic Fractures/diagnostic imaging , Osteoporotic Fractures/physiopathology , Pancreatitis, Chronic/diagnostic imaging , Pancreatitis, Chronic/physiopathology , Prevalence , Prognosis , Retrospective Studies , Risk Assessment , Risk Factors , Sweden/epidemiology
12.
Commun Biol ; 4(1): 90, 2021 01 19.
Article in English | MEDLINE | ID: mdl-33469151

ABSTRACT

Leucine-rich repeats and immunoglobulin-like domains (LRIG) proteins have been implicated as regulators of growth factor signaling; however, the possible redundancy among mammalian LRIG1, LRIG2, and LRIG3 has hindered detailed elucidation of their physiological functions. Here, we show that Lrig-null mouse embryonic fibroblasts (MEFs) are deficient in adipogenesis and bone morphogenetic protein (BMP) signaling. In contrast, transforming growth factor-beta (TGF-ß) and receptor tyrosine kinase (RTK) signaling appeared unaltered in Lrig-null cells. The BMP signaling defect was rescued by ectopic expression of LRIG1 or LRIG3 but not by expression of LRIG2. Caenorhabditis elegans with mutant LRIG/sma-10 variants also exhibited a lipid storage defect. Human LRIG1 variants were strongly associated with increased body mass index (BMI) yet protected against type 2 diabetes; these effects were likely mediated by altered adipocyte morphology. These results demonstrate that LRIG proteins function as evolutionarily conserved regulators of lipid metabolism and BMP signaling and have implications for human disease.


Subject(s)
Lipid Metabolism/physiology , Membrane Glycoproteins/metabolism , Membrane Proteins/metabolism , Adipogenesis/physiology , Adult , Aged , Animals , Body Mass Index , Bone Morphogenetic Proteins/metabolism , Bone Morphogenetic Proteins/physiology , Caenorhabditis elegans , Diabetes Mellitus, Type 2/metabolism , Female , Fibroblasts/metabolism , Humans , Male , Membrane Glycoproteins/physiology , Membrane Proteins/physiology , Mice , Middle Aged , Prognosis , Risk Factors , Signal Transduction/physiology
14.
Physiol Rep ; 8(16): e14538, 2020 08.
Article in English | MEDLINE | ID: mdl-32812397

ABSTRACT

BACKGROUND: In obesity, the expression level of thyroid stimulating hormone receptor in adipose tissue is reduced and the levels of thyroid stimulating hormone (TSH) are often elevated within the normal range. PURPOSE/AIM: To investigate the role of TSHR in brown and white adipose tissue (AT) using TSHR knockout (KO) mice and the physiological phenotypes affected by the TSHR knockout. METHODS: AT-specific TSHR KO male mice and wild type (WT) controls were given a high-fat diet (HFD) or a control diet (CD). Body weights and food consumption were recorded for 20 weeks and body temperatures for the first 3 weeks. At termination, white and brown adipocytes were isolated. Gene expressios was investigated using real-time PCR. In a subgroup of female KO mice, glucose tolerance was investigated. RESULTS: TSHR were partially knocked out in KO mice, which gained more weight than WT mice when fed both a CD (p = .03) and HFD (p = .003). Body temperatures were lower in KO mice on CD (p <.001) and on HFD (p <.001) than WT controls. This was in agreement with reduced gene expression of UCP1 in brown adipocytes in the KO mice. Glucose tolerance was significantly impaired in KO mice on CD mice before termination (p <.01). Expression of adipogenic and lipolytic genes were reduced in KO mice, which was exacerbated by HFD. The mRNA levels of adipokines including ADIPOQ and LEP were altered in white adipocytes of KO mice. CONCLUSIONS: TSHR KO led to dysfunction of both white and brown AT and predisposition to excess body weight gain in mice. Our data show that TSHR in AT regulates glucose tolerance, lipid metabolism, adipokine profile, and thermogenesis.


Subject(s)
Adipocytes/metabolism , Body Temperature , Body Weight , Receptors, Thyrotropin/metabolism , Animals , Cells, Cultured , Gene Deletion , Male , Mice , Mice, Inbred C57BL , Receptors, Thyrotropin/genetics , Transcriptome , Weight Gain
15.
Cell Metab ; 32(1): 1-3, 2020 07 07.
Article in English | MEDLINE | ID: mdl-32589948

ABSTRACT

Gao et al. report that the observed reduction in adipose lipolysis with age in women could be explained by an upregulation of the catecholamine-degradation pathway in subcutaneous adipocytes. However, in contrast to findings in mice, these pathways are enriched in adipocytes and not in immune cells, suggesting species-specific differences in aging mechanisms.


Subject(s)
Inflammasomes , Lipolysis , Adipocytes , Adipose Tissue/metabolism , Aging , Animals , Catecholamines/metabolism , Humans , Inflammasomes/metabolism , Macrophages , Mice , Norepinephrine
16.
Cells ; 9(5)2020 04 27.
Article in English | MEDLINE | ID: mdl-32349335

ABSTRACT

An increased adipocyte size relative to the size of fat depots, also denoted hypertrophic adipose morphology, is a strong risk factor for the future development of insulin resistance and type 2 diabetes. The regulation of adipose morphology is poorly understood. We set out to identify genetic loci associated with adipose morphology and functionally evaluate candidate genes for impact on adipocyte development. We performed a genome-wide association study (GWAS) in the unique GENetics of Adipocyte Lipolysis (GENiAL) cohort comprising 948 participants who have undergone abdominal subcutaneous adipose biopsy with a determination of average adipose volume and morphology. The GWAS identified 31 genetic loci displaying suggestive association with adipose morphology. Functional evaluation of candidate genes by small interfering RNAs (siRNA)-mediated knockdown in adipose-derived precursor cells identified six genes controlling adipocyte renewal and differentiation, and thus of potential importance for adipose hypertrophy. In conclusion, genetic and functional studies implicate a regulatory role for ATL2, ARHGEF10, CYP1B1, TMEM200A, C17orf51, and L3MBTL3 in adipose morphology by their impact on adipogenesis.


Subject(s)
Adipocytes/cytology , Diabetes Mellitus, Type 2/genetics , Obesity/genetics , Adipocytes/physiology , Adipogenesis/genetics , Adipose Tissue/cytology , Adipose Tissue/metabolism , Adiposity , Adult , Cell Differentiation , Cohort Studies , Diabetes Mellitus, Type 2/metabolism , Female , Genome-Wide Association Study/methods , Humans , Insulin/metabolism , Insulin Resistance/physiology , Lipolysis/physiology , Male , Middle Aged , Subcutaneous Fat
17.
Mol Metab ; 34: 85-96, 2020 04.
Article in English | MEDLINE | ID: mdl-32180562

ABSTRACT

OBJECTIVES: Lipolysis, hydrolysis of triglycerides to fatty acids in adipocytes, is tightly regulated, poorly understood, and, if perturbed, can lead to metabolic diseases including obesity and type 2 diabetes. The goal of this study was to identify the genetic regulators of lipolysis and elucidate their molecular mechanisms. METHODS: Adipocytes from abdominal subcutaneous adipose tissue biopsies were isolated and were incubated without (spontaneous lipolysis) or with a catecholamine (stimulated lipolysis) to analyze lipolysis. DNA was extracted and genome-wide genotyping and imputation conducted. After quality control, 939 samples with genetic and lipolysis data were available. Genome-wide association studies of spontaneous and stimulated lipolysis were conducted. Subsequent in vitro gene expression analyses were used to identify candidate genes and explore their regulation of adipose tissue biology. RESULTS: One locus on chromosome 19 demonstrated genome-wide significance with spontaneous lipolysis. 60 loci showed suggestive associations with spontaneous or stimulated lipolysis, of which many influenced both traits. In the chromosome 19 locus, only HIF3A was expressed in the adipocytes and displayed genotype-dependent gene expression. HIF3A knockdown in vitro increased lipolysis and the expression of key lipolysis-regulating genes. CONCLUSIONS: In conclusion, we identified a genetic regulator of spontaneous lipolysis and provided evidence of HIF3A as a novel key regulator of lipolysis in subcutaneous adipocytes as the mechanism through which the locus influences adipose tissue biology.


Subject(s)
Adipocytes/metabolism , Genome-Wide Association Study , Lipolysis/genetics , Adipose Tissue/metabolism , Adult , Apoptosis Regulatory Proteins/deficiency , Apoptosis Regulatory Proteins/genetics , Chromosomes, Human, Pair 19/genetics , Female , Humans , Male , Middle Aged , Phenotype , Repressor Proteins/deficiency , Repressor Proteins/genetics
19.
Int J Obes (Lond) ; 44(2): 377-387, 2020 02.
Article in English | MEDLINE | ID: mdl-31164724

ABSTRACT

BACKGROUND: Transcriptome analysis of abdominal subcutaneous white adipose tissue (sWAT) has identified important obesity-associated disturbances. However, the relation between sWAT transcriptome and long-term future changes in body weight remains elusive. OBJECTIVE: To investigate sWAT transcriptome signatures before and after long-term weight changes and assess their predictive value for body weight changes. DESIGN: A total of 56 women were followed longitudinally and subdivided into weight-stable (WS, n = 25), weight-gaining (WG, n = 14) and weight-losing (WL, n = 17) groups between baseline and follow-up (13 ± 1 years). The fasting sWAT transcriptome was analyzed by gene microarray at baseline and follow-up. Key genes associated with weight changes were validated using quantitative real-time PCR. RESULTS: In total 285 transcripts exhibited difference (FDR < 30%) in expression fold change over time between WL and WS women. WL women displayed decreased pro-inflammatory (NLRP3) but increased insulin-response gene (FASN and GLUT4) expression over time. In comparison, 461 transcripts displayed difference in expression fold change over time between WG and WS women (P < 0.05). Genes involved in autophagic processes (CDK5, SQSTM1 and FBXL2) were generally upregulated in WG women. At baseline, 307 and 302 transcripts were differentially expressed (FDR < 30%) in WL and WG women, respectively, when independently compared against WS women. Baseline expression of adipogenic and lipogenic genes (PPARG, IRS2 and HACD2) was lower, while pro-fibrotic (COL6A1) was higher, in WL than WS women; whereas protein processing genes were lower expressed in WG than in WS women. CONCLUSION: In adult women, long-term body weight change associates with altered sWAT transcriptome. Expression of genes associated with inflammation, insulin response, adipogenesis and lipogenesis are linked to weight loss. However, other pathways such as autophagy not only associate but also predict future weight gain suggesting that intrinsic factors in sWAT impact tissue expansion.


Subject(s)
Body Weight , Obesity , Subcutaneous Fat, Abdominal/metabolism , Transcriptome/genetics , Adult , Body Weight/genetics , Body Weight/physiology , Female , Humans , Inflammation/genetics , Lipogenesis/genetics , Middle Aged , Obesity/genetics , Obesity/metabolism , Prospective Studies
20.
Nutrients ; 11(12)2019 Dec 03.
Article in English | MEDLINE | ID: mdl-31816875

ABSTRACT

A healthy dietary pattern is associated with a lower risk of metabolic syndrome (MetS) and reduced inflammation. To explore this at the molecular level, we investigated the effect of a Nordic diet (ND) on changes in the gene expression profiles of inflammatory and lipid-related genes in peripheral blood mononuclear cells (PBMCs) of individuals with MetS. We hypothesized that the intake of an ND compared to a control diet (CD) would alter the expression of inflammatory genes and genes involved in lipid metabolism. The individuals with MetS underwent an 18/24-week randomized intervention to compare a ND with a CD. Eighty-eight participants (66% women) were included in this sub-study of the larger SYSDIET study. Fasting PBMCs were collected before and after the intervention and changes in gene expression levels were measured using TaqMan Array Micro Fluidic Cards. Forty-eight pre-determined inflammatory and lipid related gene transcripts were analyzed. The expression level of the gene tumor necrosis factor (TNF) receptor superfamily member 1A (TNFRSF1A) was down-regulated (p = 0.004), whereas the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) subunit, RELA proto-oncogene, was up-regulated (p = 0.016) in the ND group compared to the CD group. In conclusion, intake of an ND in individuals with the MetS may affect immune function.


Subject(s)
Diet Therapy , Leukocytes, Mononuclear/drug effects , Metabolic Syndrome/diet therapy , Receptors, Tumor Necrosis Factor, Type I/metabolism , Transcription Factor RelA/metabolism , Adult , Female , Gene Expression Regulation/drug effects , Humans , Male , Middle Aged , Proto-Oncogene Mas , Receptors, Tumor Necrosis Factor, Type I/genetics , Transcription Factor RelA/genetics , Transcriptome
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