Alina Kurylowicz

SIRT1 and SIRT7 expression in adipose tissues of obese and normal-weight individuals is regulated by microRNAs but not by methylation status

Background/Objective:Given their importance in the regulation of metabolism, sirtuins (SIRTs) constitute promising subjects of research on the pathogenesis of obesity and the metabolic syndrome. The aim of this study was to assess whether obesity in humans is associated with changes in the expression of SIRT genes in adipose tissue and whether epigenetic mechanisms, DNA methylation and microRNA (miRNA) interference, mediate in this phenomenon.Subjects/Methods:The expression of SIRTs and of SIRT1 and SIRT7 mRNA-interacting miRNAs was evaluated by real-time PCR in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) of 58 obese (body mass index (BMI) >40 kg m−2) and 31 normal-weight (BMI 20–24.9 kg m−2) individuals. The methylation status of SIRTs was studied by the methylation-sensitive digestion/real-time PCR method.Results:SIRT1 mRNA levels were lower in adipose tissues of obese patients than of normal-weight controls (VAT: P=0.0002, SAT: P=0.008). In contrast, expression of SIRT7 was higher in adipose tissues of obese patients than in the control group (VAT: P=0.001, SAT: P=0.008). The mean methylation of the SIRT1 and SIRT7 CpG islands was similar in tissues with high and low expression of these genes, and there was no correlation between the level of expression and the level of methylation. On the other hand, expression of SIRT1 in VAT of obese subjects correlated negatively with the expression of miR-22-3p (P<0.0001, rs=−0.514), miR-34a-5p (P=0.01, rs=−0.326) and miR-181a-3p (P<0.0001, rs=−0.536). In turn, expression of SIRT7 in VAT of slim individuals correlated negatively with the expression of miR-125a-5p (P=0.003, rs=−0.562) and miR-125b-5p (P=0.018, rs=−0.460).Conclusions:We observed obesity-associated downregulation of SIRT1 and upregulation of SIRT7 mRNA levels that were not associated with the methylation status of their promoters. We found a negative correlation between mRNA levels of SIRT1 in VAT of obese individuals and SIRT7 in VAT of the normal-weight subjects and expression of the relevant miRNAs.

Interleukin‐13 gene polymorphisms in patients with Graves’ disease

objective  In patients with Graves’ disease (GD), an elevation of serum immunoglobulin E (IgE) has been recently reported to be associated with the severity of hyperthyroidism and ophthalmopathy. Interleukin 13 (IL‐13) is a major cytokine involved in IgE synthesis and therefore may be a potential candidate gene contributing to the development of GD or influencing the clinical course of the disease.

Interleukins 6 and 15 Levels Are Higher in Subcutaneous Adipose Tissue, but Obesity Is Associated with Their Increased Content in Visceral Fat Depots

Excess adiposity is associated with chronic inflammation, which takes part in the development of obesity-related complications. The aim of this study was to establish whether subcutaneous (SAT) or visceral (VAT) adipose tissue plays a major role in synthesis of pro-inflammatory cytokines. Concentrations of interleukins (IL): 1β, 6, 8 and 15 were measured at the protein level by an ELISA-based method and on the mRNA level by real-time PCR in VAT and SAT samples obtained from 49 obese (BMI > 40 kg/m2) and 16 normal-weight (BMI 20–24.9 kg/m2) controls. IL-6 and IL-15 protein concentrations were higher in SAT than in VAT for both obese (p = 0.003 and p < 0.0001, respectively) and control individuals (p = 0.004 and p = 0.001, respectively), while for IL-1β this was observed only in obese subjects (p = 0.047). What characterized obese individuals was the higher expression of IL-6 and IL-15 at the protein level in VAT compared to normal-weight controls (p = 0.047 and p = 0.016, respectively). Additionally, obese individuals with metabolic syndrome had higher IL-1β levels in VAT than did obese individuals without this syndrome (p = 0.003). In conclusion, concentrations of some pro-inflammatory cytokines were higher in SAT than in VAT, but it was the increased pro-inflammatory activity of VAT that was associated with obesity and metabolic syndrome.

Functional polymorphisms of the leptin and leptin receptor genes are associated with longevity and with the risk of myocardial infarction and of type 2 diabetes mellitus.

INTRODUCTION Longevity is commonly associated with good health and with delayed onset of age-related diseases with usually benign course. Leptin (LEP) significantly affects metabolism and numerous functions of the organism. To find out if extreme longevity and its phenotype are associated with genetic variants of leptin and leptin receptor (LEPR) genes, we analysed the frequencies of the -2548 G/A and +19 G/A LEP, as well as the K109R, Q223R, and K656N LEPR polymorphisms in centenarians and in control groups. MATERIAL AND METHODS The frequencies of the LEP and LEPR polymorphisms were tested by restriction fragment length polymorphism in 128 centenarians, 414 young controls (Y), 226 myocardial infarction (MI) patients, and 190 type 2 diabetes mellitus (DM2) patients. RESULTS The GG genotype of the -2548 G/A LEP polymorphism was significantly more common in centenarians than in the Y, MI and DM2 groups (p = 0.048, p = 0.003, p = 0.049, respectively). In addition, the AA genotype of the K109R LEPR polymorphism was significantly less frequent in centenarians than in the Y, MI, and DM2 groups (p = 0.026, p = 0.013, and p = 0.001, respectively). CONCLUSIONS We suggest that the leptin pathway plays a role in the regulation of longevity, possibly by modulating the risk of development of MI and of DM2.

The —351A/G polymorphism of ESR1 is associated with risk of myocardial infarction but not with extreme longevity

BACKGROUND Women live longer than men. Some possible reasons for this advantage are the protection provided by high concentrations of 17β-estradiol (E2) during the premenopausal period and polymorphic variants of the estrogen receptors (ERs), which mediate various cardiovascular functions of E2. METHODS We tested whether the -351A/G and -397T/C polymorphisms of the ERα-encoding ESR1 were associated with extreme longevity. The genomic DNA of 148 centenarians (C), 414 young controls (Y), and 208 myocardial infarction patients (MI) was analyzed by RFLP-PCR. RESULTS Both polymorphisms were equally distributed in the Y, C, and in centenarians never diagnosed with MI (HC). In centenarians, none of these polymorphisms was associated with a particular lipid profile. The AA genotype of the -351A/G polymorphism was less frequent in the C, HC and Y groups than in MI patients (p=0.058, p=0.021, and p=0.004, respectively). In MI patients, the GG genotype of the -351A/G polymorphism was associated with significantly lower mean total cholesterol, LDL, and HDL levels compared to the AG (p=0.0194, p=0.0213, and p=0.0367, respectively) and AA genotypes (p=0.0014, p=0.0078, and p=0.0448, respectively). CONCLUSIONS The -351A/G ESR1 polymorphism might be associated with MI, but not with extreme longevity.

The diagnosis of nonclassic congenital adrenal hyperplasia due to 21-hydroxylase deficiency, based on serum basal or post-ACTH stimulation 17-hydroxyprogesterone, can lead to false-positive diagnosis.

As nonclassic congenital adrenal hyperplasia (NCCAH) needs to be taken into account in women with hyperandrogenism, we aimed to assess whether the recommended level of poststimulated 17OHP ≥30 nmol/l confirms NCCAH.

Aging is accompanied by a progressive decrease of expression of the WRN gene in human blood mononuclear cells.

The WRN gene encodes DNA helicase participating in genome maintenance. We looked for associations of natural aging with expression and methylation of this gene in blood mononuclear cells and with its common polymorphisms. Analyses were performed in ethnically homogenous Polish Caucasians. The mean level of the WRN messenger RNA was significantly lower in long-living individuals than in young and middle-aged controls (p < .001 and p = .025, respectively). Analysis of the 361 bp WRN promoter CpG island showed that aging might be accompanied by a slight increase of its methylation status; however, it seems to be biologically insignificant. Finally, analysis of the WRN R834C, L1074F, and C1367R polymorphisms showed that the frequencies of the L1074F and C1367R polymorphisms were similar in all age groups tested, whereas the R834C polymorphism was absent from Polish Caucasians. We suggest that age-related decrease of the WRN expression but not its common genetic variants might contribute to human immunosenescence.

ADIPOQ -11377C>G Polymorphism Increases the Risk of Adipokine Abnormalities and Child Obesity Regardless of Dietary Intake.

Objective: The aim of the present study was to verify whether selected functional single nucleotide polymorphisms in LEP, LEPR, and ADIPOQ loci are associated with the development of obesity and serum levels of the respective adipokines in prepubertal white children with obesity. Methods: Frequencies of −2548G>A LEP (rs7799039), Q223R (rs1137101) and K656N (rs8129183) LEPR, and −11377C>G (rs266729) and −11426A>G (rs16861194) ADIPOQ polymorphisms were analyzed by restriction fragment length polymorphism in 101 obese (standard deviation score [SDS]-body mass index [BMI] >2) and 67 normal-weight (SDS-BMI <−1 + 1>) children. Serum adipokine concentrations were measured using the enzyme-linked immunosorbent assay method. Results: The GC/GG genotypes of −11377C>G ADIPOQ polymorphism were associated with a higher risk of obesity (P = 0.022, odds ratio 2.08 [95% confidence interval 1.11–3.90]). Individuals carrying the GG genotype had a higher leptin/total adiponectin ratio by 25% than CC homozygotes (Ptrend = 0.05). In the multivariate linear regression model, we found differences among particular genotypes of this polymorphism in concentrations of high molecular weight (HMW) adiponectin (Ptrend = 0.043) and HMW/total adiponectin ratio (Ptrend = 0.048), with the lowest values in GG homozygotes. Positive correlations between SDS-BMI and dietary reference intake percentage were observed in individuals homozygous for allele C (r = 0.403, P = 0.01) and CG heterozygotes (r = 0.428, P = 0.004). No significant correlations between both parameters were found in the GG homozygotes. Conclusions: Among the analyzed polymorphisms, only −11377C>G ADIPOQ single nucleotide polymorphism was associated with obesity during the prepubertal period. Adipokine abnormalities coexisting with the lack of relations between SDS-BMI and dietary intake may predict a higher risk of future obesity-related disorders in obese children carrying the GG genotype than in those with other genotypes.

Synthetic and Natural Lipase Inhibitors

Lipases are enzymes that catalyse the hydrolysis of ester bonds of triglycerides ranging among biocatalysts of considerable physiological significance and industrial potential. Better understanding of the catalytic functions and achieving the possibility to control the biocatalysis process, in particular exploring some activators and inhibitors of lipases, seems to be crucial in the context of novel applications. The lipase activity is a function of interfacial composition: the enzyme can be there activated as well as denaturated or deactivated and the interface is an appropriate site for modulating lipolysis. Lipase inhibitor, interacts directly with the enzyme and inhibits lipase action. Alternatively, some compounds can postpone the lipolytic reaction via adsorption to the interphase or to the substrate molecules. The aim of this review is to summarise the current knowledge concerning human, animal and microbial lipase inhibitors, which were grouped into two categories: synthetic lipase inhibitors (including phosphonates, boronic acids and fats analogues) and natural compounds (including β-lactones and some botanical foodstuffs - plant extracts and plant metabolites, mainly polyphenols and saponins as well as peptides and some dietary fibers). The topics discussed include also inhibition issues from the viewpoint of obesity treatment. Among natural compounds able to inhibit lipase activity are β- lactones including orlistat. Orlistat is the only registered drug for obesity treatment in many countries and lipases are essential enzymes for lipid absorption - thus fat absorption or obesity can be controlled by lipase inhibition, especially pancreatic lipase which is responsible for the hydrolysis of over 80% of total dietary fats. Its effectiveness in obesity treatment was also described.

Complementary Effects of Genetic Variations in LEPR on Body Composition and Soluble Leptin Receptor Concentration after 3-Month Lifestyle Intervention in Prepubertal Obese Children

In obese individuals, weight loss might be affected by variants of the adipokine-encoding genes. We verified whether selected functional single nucleotide polymorphisms in LEP, LEPR and ADIPOQ are associated with changes in serum levels of the respective adipokines and weight loss in 100 prepubertal obese (SDS-BMI > 2) Caucasian children undergoing lifestyle intervention. Frequencies of the -2548G > A LEP, Q223R LEPR, K656N LEPR, -11377C > G and -11426A > G ADIPOQ polymorphisms were analyzed by restriction fragment length polymorphism. Serum adipokine and soluble leptin receptor (sOB-R) concentrations were measured using the ELISA method. Among the analyzed polymorphisms, only LEPR polymorphisms were associated with changes of SDS-BMI or sOB-R concentrations in children after therapy. Carriers of the wild-type K665N and at least one minor Q223R allele had the greatest likelihood of losing weight (OR = 5.09, p = 0.006), an increase in sOB-R (ptrend = 0.022) and decrease in SDS-BMI correlated with the decrease of fat mass (p < 0.001). In contrast, carrying of the wild-type Q223R and at least one minor K665N allele were associated with a decrease in sOB-R concentrations and a decrease in SDS-BMI correlated with a decrease in fat-free mass (p = 0.002). We suggest that the combination of different LEPR variants, not a single variant, might determine predisposition to weight loss in the prepubertal period.