Effect of the beta-3 adrenergic receptor Trp64Arg and uncoupling protein 1-3826 A>G genotypes on lipid and apolipoprotein levels in overweight/obese and non-obese Chinese subjects

Interactions of Apolipoproteins with Lipid-Based Nanoparticles

Serum proteins bind and form a dynamic protein corona around nanoparticles (NPs) that have been injected into the mammalian vasculature. Several fundamental studies have shown that apolipoproteins are prominent components of the NP corona. Since apolipoproteins control the distribution of lipoproteins, they may also control the distribution of NPs. Indeed, apolipoprotein affinity for NPs has been recently taken advantage of to deliver CRISPR reagents encapsulated in NPs to cells that express particular lipoprotein receptors. In this scenario, an apolipoprotein binds an NP and the resulting apolipoprotein-NP complex binds a cell that expresses the (apo)lipoprotein receptor. But the NP will be diverted from the target cell if it does not express the (apo)lipoprotein receptor. This may hamper NP treatment of diseases. Therefore, we must understand the kinetics of apolipoprotein-NP affinity and how apolipoprotein-NP interactions affect NP biodistribution. In this Perspective, we discuss the evolving topic of apolipoprotein-NP interactions, which is of great interest for all NP-based disease treatments. Many properties of apolipoprotein-NP complexes are yet to be determined and will have a significant impact on NP efficacy for many NP-based treatments in animal models and in the clinic.

Association of Type 2 Deiodinase Thr92Ala Polymorphism with Pediatric Obesity in Japanese Children: A Case-Control Study

Genetic factors play critical roles in the onset and progression of obesity. Brown adipose tissue (BAT) activity is also critical for adiposity. The objective of this study was to evaluate the prevalence and effects of BAT gene polymorphisms in pediatric obesity. This case-control study included 270 non-obese and 86 obese children. All participants underwent genotyping for type 2 deiodinase (DIO2) Thr92Ala (rs225014). The prevalence of the homozygous Ala/Ala allele of the DIO2 gene in the obese group was 15.1% versus 6.3% in the non-obese group, resulting in an odds ratio (OR) of 3.393 (p = 0.003). The results of this study indicate that the homozygous Ala/Ala allele of the DIO2 gene is associated with an increased risk of pediatric obesity and suggest that pediatric obesity might be suitable for assessing the association with gene polymorphisms related to BAT, especially DIO2 Thr92Ala.

Prevalence of uncoupling protein one genetic polymorphisms and their relationship with cardiovascular and metabolic health

Contribution of UCP1 single nucleotide polymorphisms (SNPs) to susceptibility for cardiometabolic pathologies (CMP) and their involvement in specific risk factors for these conditions varies across populations. We tested whether UCP1 SNPs A-3826G, A-1766G, Ala64Thr and A-112C are associated with common CMP and their risk factors across Armenia, Greece, Poland, Russia and United Kingdom. This case-control study included genotyping of these SNPs, from 2,283 Caucasians. Results were extended via systematic review and meta-analysis. In Armenia, GA genotype and A allele of Ala64Thr displayed ~2-fold higher risk for CMP compared to GG genotype and G allele, respectively (p<0.05). In Greece, A allele of Ala64Thr decreased risk of CMP by 39%. Healthy individuals with A-3826G GG genotype and carriers of mutant allele of A-112C and Ala64Thr had higher body mass index compared to those carrying other alleles. In healthy Polish, higher waist-to-hip ratio (WHR) was observed in heterozygotes A-3826G compared to AA homozygotes. Heterozygosity of A-112C and Ala64Thr SNPs was related to lower WHR in CMP individuals compared to wild type homozygotes (p<0.05). Meta-analysis showed no statistically significant odds-ratios across our SNPs (p>0.05). Concluding, the studied SNPs could be associated with the most common CMP and their risk factors in some populations.

β2 adrenergic interaction and cardiac autonomic function: effects of aerobic training in overweight/obese individuals

PURPOSE

To verify the influence of different volumes and intensities of aerobic exercise on cardiac autonomic function (CAF) through heart rate variability (HRV) analysis as well the influence of β2 adrenergic receptor (ADRB2) variants in overweight/obese individuals.

METHODS

70 physically inactive adults were randomly allocated into the following 16-week training: 1-high-intensity interval training (HIIT) (n = 25, 1 × 4 min bout at 85-95%HR peak, 3×/week), 4-HIIT (n = 26, 4 × 4 min bouts at 85-95%HR peak, interspersed with 3 min of recovery at 50-70%HR peak, 3×/week), and moderate continuous training (MCT) (n = 19, 30 min at 60-70%HR peak, 5×/week). Before and after the exercise training, anthropometric, BP, cardiorespiratory fitness, and HRV measures were evaluated. R-R intervals recorded for 10 min in a supine position at pre- and post-intervention were used to analyze HRV in the plot-Poincare indexes (SD1, SD2), and frequency-domain (LF, HF, LF/HF). Full blood samples were used for genotyping.

RESULTS

4-HIIT and MCT showed positive outcomes for almost all variables while 1-HIIT had a positive influence only on SBP and SD2 index. No associations were observed between isolated ADRB2 variants and changes in HRV. In the analysis of the interaction genotypes, all groups responded positively for the SD1 index of HRV and only the H1 (GG and CC) and H2 (GG and CG + GG) groups presented increases in the RMSSD index. Furthermore, there was an increase in the LF index only in the H3 (CC and AA + AG) and H4 (AA + AG and CG + GG) groups.

CONCLUSIONS

ADRB2 variants and aerobic exercise training are important interacting variables to improve autonomic function and other health variables outcomes in overweight or obese individuals.

Stratified meta-analysis by ethnicity revealed that ADRB3 Trp64Arg polymorphism was associated with coronary artery disease in Asians, but not in Caucasians

BACKGROUND

Previous studies demonstrated that ADRB3, beta-3 adrenergic receptor, participated in lipolysis and thermogenesis in adipose tissue. Consequently, this gene has attracted an increasing number of genetic studies examining its association with coronary artery disease (CAD) in different ethnicities in recent years, but no conclusion has been reached so far. The aim of this study was to explore whether the well-studied locus ADRB3 Trp64Arg in this gene confers a race-specific effect to CAD by conducting a stratified meta-analysis involving 15 independent studies and 11,802 subjects.

METHODS

Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the strength of association. Publication bias was quantified and examined with Begg's funnel plot test and Egger's linear regression method. The overall meta-analysis or stratified meta-analysis by ethnicity was performed by using STATA 12.0 software.

RESULTS

A total of 15 eligible studies involving 5779 CAD cases and 6023 health controls were included in this meta-analysis. The pooled results indicated that ADRB3 Trp64Arg polymorphism was significantly associated with an increased risk of CAD. Further stratified analysis by ethnicity revealed that ADRB3 Trp64Arg polymorphism was significantly associated with CAD in Asians (allelic: OR = 1.48, 95%CI 1.13-1.94, P = .005; homozygous: OR = 2.66, 95%CI 1.87-3.77, P < .001; recessive: OR = 2.46, 95%CI 1.74-3.47, P < .001), but not in Caucasians (allelic: OR = 1.09, 95%CI 0.93-1.27, P = .290; homozygous: OR = 1.31, 95%CI 0.61-2.86, P = .490; recessive: OR = 1.31, 95%CI 0.60-2.84, P = 2.494).

CONCLUSIONS

This meta-analysis suggests that ADRB3 Trp64Arg polymorphism confers a race-specific effect to CAD.

Transcriptional regulation of the uncoupling protein-1 gene

Regulated transcription of the uncoupling protein-1 (UCP1) gene, and subsequent UCP1 protein synthesis, is a hallmark of the acquisition of the differentiated, thermogenically competent status of brown and beige/brite adipocytes, as well as of the responsiveness of brown and beige/brite adipocytes to adaptive regulation of thermogenic activity. The 5' non-coding region of the UCP1 gene contains regulatory elements that confer tissue specificity, differentiation dependence, and neuro-hormonal regulation to UCP1 gene transcription. Two main regions-a distal enhancer and a proximal promoter region-mediate transcriptional regulation through interactions with a plethora of transcription factors, including nuclear hormone receptors and cAMP-responsive transcription factors. Co-regulators, such as PGC-1α, play a pivotal role in the concerted regulation of UCP1 gene transcription. Multiple interactions of transcription factors and co-regulators at the promoter region of the UCP1 gene result in local chromatin remodeling, leading to activation and increased accessibility of RNA polymerase II and subsequent gene transcription. Moreover, a commonly occurring A-to-G polymorphism in close proximity to the UCP1 gene enhancer influences the extent of UCP1 gene transcription. Notably, it has been reported that specific aspects of obesity and associated metabolic diseases are associated with human population variability at this site. On another front, the unique properties of the UCP1 promoter region have been exploited to develop brown adipose tissue-specific gene delivery tools for experimental purposes.