The association of a nucleobindin 2 gene (NUCB2) variant with childhood adiposity

Influence of NUCB/Nesfatin-1 Polymorphism on Treatment Response to Naltrexone/Bupropion SR in Binge Eating Disorder and Obesity

Background and Objectives: The NUCB2 gene and its polymorphisms were identified as novel players in the regulation of food intake, potentially leading to obesity (OBE) and altered eating behaviors. Naltrexone/bupropion SR (NB) showed good efficacy and tolerability for treating OBE and altered eating behaviors associated with binge eating disorder (BED). This prospective study investigates the influence of NUCB2 gene polymorphism on NB treatment response in OBE and BED. Materials and Methods: Body mass index (BMI), eating (EDE-Q, BES, NEQ, GQ, Y-FAS 2.0) and general psychopathology (BDI, STAI-S) were evaluated at baseline (t0) and after 16 weeks (t1) of NB treatment in patients with OBE and BED (Group 1; N = 22) vs. patients with OBE without BED (Group 2; N = 20). Differences were evaluated according to the rs757081 NUCB2 gene polymorphism. Results: NUCB2 polymorphism was equally distributed between groups. Although weight at t0 was higher in Group 1, weight loss was similar at t1 in both groups. BMI was not influenced by NUCB2 polymorphism. In Group 1, the CG-genotype reported significant improvement in eating psychopathology while the GG-genotype reported improvement only for FA. No differences were observed in Group 2. Conclusions: Patients diagnosed with BED and treated with NB exhibited a more favorable treatment response within the CG-genotype of the NUCB2 polymorphism.

Does NUCB2/Nesfatin-1 Influence Eating Behaviors in Obese Patients with Binge Eating Disorder? Toward a Neurobiological Pathway

Nesfatin-1 is a new anorexigenic neuropeptide involved in the regulation of hunger/satiety, eating, and affective disorders. We aimed to investigate nesfatin-1 secretion in vitro, in murine adipose cells, and in human adipose fat samples, as well as to assess the link between circulating nesfatin-1 levels, NUCB2 and Fat Mass and Obesity Gene (FTO) polymorphisms, BMI, Eating Disorders (EDs), and pathological behaviors. Nesfatin-1 secretion was evaluated both in normoxic fully differentiated 3T3-L1 mouse adipocytes and after incubation under hypoxic conditions for 24 h. Omental Visceral Adipose tissue (VAT) specimens of 11 obese subjects, and nesfatin-1 serum levels' evaluation, eating behaviors, NUCB2 rs757081, and FTO rs9939609 polymorphisms of 71 outpatients seeking treatment for EDs with different Body Mass Index (BMI) were studied. Significantly higher levels of nesfatin-1 were detected in hypoxic 3T3-L1 cultured adipocytes compared to normoxic ones. Nesfatin-1 was highly detectable in the VAT of obese compared to normal-weight subjects. Nesfatin-1 serum levels did not vary according to BMI, sex, and EDs diagnosis, but correlations with grazing; emotional, sweet, and binge eating; hyperphagia; social eating; childhood obesity were evident. Obese subjects with CG genotype NUCB2 rs757081 and AT genotype FTO rs9939609 polymorphisms had higher nesfatin-1 levels. It could represent a new biomarker of EDs comorbidity among obese patients.

NUCB2 polymorphisms are associated with an increased risk for type 2 diabetes in the Chinese population

Background

The nucleobindin 2 (NUCB2) gene encodes the NUCB2 protein, which plays a critical role in glucose metabolism and diabetes. This study explored the correlation between NUCB2 genetic variants and type 2 diabetes mellitus (T2DM). The study further examined the different NUCB2 variants that confer risk to T2DM in Chinese Han populations.

Methods

This study evaluated the anthropometric and glycemic profiles of 578 T2DM patients and 1,609 healthy controls. Subsequently, we genotyped five single nucleotide polymorphisms (SNPs) (rs10832756, rs1330, rs10766383, rs10832757, and rs11024251) in all the study participants using a Sequenom Mass ARRAY SNP genotyping platform.

Results

The distribution of polymorphisms was significantly different between the T2DM patients and healthy controls. Our logistic regression analysis results showed that the five NUCB2 SNPs are significantly correlated with the risk for T2DM, especially rs11024251(P=2.97×10⁻⁶). Interestingly, analysis of male and female sub-populations separately showed that only two of the SNPs (rs10832757 and rs11024251) have significant correlation to T2DM in males [P=0.0244, odds ratio (OR) 1.28 and P=0.0062, OR 1.35, respectively). In females however, we identified four significant SNPs (rs1330, rs10766383, rs10832757, and rs11024251; P<0.05, OR 1.31–1.42). Furthermore, we found that rs1330 is associated with body mass index of female subpopulation only (P=0.0174, β =0.0060).

Conclusions

NUCB2 polymorphisms could have a pivotal role in the presence of T2DM. Sex-specific SNPs of NUCB2 could account for the differences in clinical features of T2DM between male and female subpopulations. Nevertheless, our results should be replicated using larger sample sizes, and experimental investigations are needed to elucidate the molecular mechanisms of the associations observed in this study.

Relation of serum and vitreous nesfatin-1 concentrations with diabetic retinopathy

OBJECTIVE

Nesfatin-1, belonging to adipokine family, serves as an anti-inflammatory mediator. We performed this investigation to evaluate the relation between serum and vitreous nesfatin-1 concentrations with diabetic retinopathy (DR).

METHODS

This study was performed in a population of 189 diabetic patients and 48 control subjects. Diabetic patients were then divided into diabetic patients without DR, non-proliferative diabetic retinopathy (NPDR) patients, and proliferative diabetic retinopathy (PDR) patients.

RESULTS

Serum and vitreous nesfatin-1 concentrations were significantly lower in the diabetic patients than in the controls. NPDR patients had reduced vitreous nesfatin-1 concentrations compared with patients without DR. In addition, there were significantly lower serum and vitreous nesfatin-1 concentrations in PDR patients compared with the other three groups. Pearson correlation analysis showed that serum nesfatin-1 was negatively correlated with body mass index and fasting plasma glucose in diabetic patients.

CONCLUSION

Serum and vitreous nesfatin-1 concentrations were negatively correlated with DR.

Nesfatin-1: functions and physiology of a novel regulatory peptide

Nesfatin-1 was identified in 2006 as a potent anorexigenic peptide involved in the regulation of homeostatic feeding. It is processed from the precursor-peptide NEFA/nucleobindin 2 (NUCB2), which is expressed both in the central nervous system as well as in the periphery, from where it can access the brain via non-saturable transmembrane diffusion. In hypothalamus and brainstem, nesfatin-1 recruits the oxytocin, the melancortin and other systems to relay its anorexigenic properties. NUCB2/nesfatin-1 peptide expression in reward-related areas suggests that nesfatin-1 might also be involved in hedonic feeding. Besides its initially discovered anorexigenic properties, over the last years, other important functions of nesfatin-1 have been discovered, many of them related to energy homeostasis, e.g. energy expenditure and glucose homeostasis. Nesfatin-1 is not only affecting these physiological processes but also the alterations of the metabolic state (e.g. fat mass, glycemic state) have an impact on the synthesis and release of NUCB2 and/or nesfatin-1. Furthermore, nesfatin-1 exerts pleiotropic actions at the level of cardiovascular and digestive systems, as well as plays a role in stress response, behavior, sleep and reproduction. Despite the recent advances in nesfatin-1 research, a putative receptor has not been identified and furthermore potentially distinct functions of nesfatin-1 and its precursor NUCB2 have not been dissected yet. To tackle these open questions will be the major objectives of future research to broaden our knowledge on NUCB2/nesfatin-1.

Association of the polymorphism in NUCB2 gene and the risk of type 2 diabetes

BACKGROUND

Nesfatin-1, originating from its precursor protein called nucleobindin 2 (NUCB2), plays an important role in glucose metabolism and diabetes. The aim of this study is to examine the association of the c.1012C>G (rs757081) polymorphism of NUCB2 gene with the presence of T2DM.

METHODS

This study was performed in a population of 396 patients with T2DM and 196 healthy subjects. The c.1012C>G polymorphism of NUCB2 gene was determined using polymerase chain reaction and sequencing method.

RESULTS

T2DM patients showed lower CG and GG genotype, as well as G allele frequencies compared with healthy subjects. Logistic regression analysis showed that c.1012C>G polymorphism was associated with a decreased risk of developing T2DM. In addition, GG genotype of NUCB2 was significantly correlated with lower levels of body mass index and fasting plasma glucose in patients with T2DM.

CONCLUSIONS

The c.1012C>G polymorphism of NUCB2 is associated with the decreased risk of developing T2DM in Chinese Han population.

NUCB2 gene polymorphism and its relationship with nesfatin-1 levels in polycystic ovary syndrome

Nesfatin-1, encoded by the nucleobindin-2 (NUCB2) gene, is an anorexigenic protein related to energy metabolism, obesity, and insulin resistance. The aim of this study was to evaluate NUCB2 gene polymorphism (rs757081) and its association with serum levels of nesfatin-1 in obese and non-obese women with polycystic ovary syndrome (PCOS). In the study population, we analyzed 60 patients with PCOS and 26 age-matched healthy women as controls. The patients with PCOS were divided into two groups based on body mass index (BMI): obese group (n = 28) or non-obese group (n = 32). NUCB2 was genotyped using the polymerase chain reaction-restriction (PCR) technique. Serum nesfatin-1 level was measured by enzyme-linked immunosorbent assay (ELISA). Nesfatin-1 levels in the obese PCOS group were significantly lower than those in the non-obese PCOS and control groups (p < 0.001). There was no statistically significant difference in the distribution of NUCB2 genotypes among the groups (p > 0.05), whereas nesfatin-1 levels in the CC and CG genotypes were lower than those in the GG genotype. Nesfatin-1 decreases in PCOS, especially in obese women, and is negatively correlated with cardiometabolic risk factors. Although genotype disturbances of NUCB2 were similar among the groups, CC and CG genotypes accompanied lower nesfatin-1 levels. C allele of NUCB2 gene polymorphism and nesfatin-1 may play a role in the pathophysiology of PCOS.

Nucleobindin 1 (NUCB1) is a Golgi-resident marker of neurons

Nucleobindin 1 (NUCB1; also known as CALNUC or NUC) is a putative DNA- and calcium-binding protein and exhibits significant structural homology with the protein nucleobindin 2 (NUCB2; also known as nesfatin). While NUCB2 has been mapped in detail in the brain and implicated in the hypothalamic control of energy metabolism, no study has to date addressed the presence of NUCB1 in the central nervous system. Here we have explored the expression and distribution of NUCB1 in the rat brain and spinal cord, using RT-PCR, immunofluorescence and in situ hybridization. NUCB1 mRNA and protein was found to be present in all brain regions, extending to the spinal cord and dorsal root ganglia. Double-staining for NUCB1 and NeuN, glial fibrillary acidic protein and myelin basic protein revealed that NUCB1 is exclusively found in neurons, and not in glial or ependymal cells. Notably, NUCB1-immunoreactivity was observed in all neurons examined, making no distinction between previously identified glutamatergic and GABAergic populations, including those that are known not to stain for NeuN. This included the markedly more restricted population of NUCB2-expressing neurons in the brain. The protein was detected in cell somata and proximal dendrites, but not in axons or terminal structures. Further examination of the subcellular distribution of NUCB1 using organelle-specific markers revealed its consistent presence in the Golgi apparatus. These findings identify NUCB1 as a novel pan-neuronal marker. Along with the recent demonstration of broad expression of the protein in endocrine cells, the present results suggest that NUCB1 may play a role in spatiotemporal calcium handling in signaling cells.

Genetics of nonsyndromic obesity

PURPOSE OF REVIEW

Common obesity is widely regarded as a complex, multifactorial trait influenced by the 'obesogenic' environment, sedentary behavior, and genetic susceptibility contributed by common and rare genetic variants. This review describes the recent advances in understanding the role of genetics in obesity.

RECENT FINDINGS

New susceptibility loci and genetic variants are being uncovered, but the collective effect is relatively small and could not explain most of the BMI heritability. Yet-to-be identified common and rare variants, epistasis, and heritable epigenetic changes may account for part of the 'missing heritability'. Evidence is emerging about the role of epigenetics in determining obesity susceptibility, mediating developmental plasticity, which confers obesity risk from early life experiences. Genetic prediction scores derived from selected genetic variants, and also differential DNA methylation levels and methylation scores, have been shown to correlate with measures of obesity and response to weight loss intervention. Genetic variants, which confer susceptibility to obesity-related morbidities like nonalcoholic fatty liver disease, were also discovered recently.

SUMMARY

We can expect discovery of more rare genetic variants with the advent of whole exome and genome sequencing, and also greater understanding of epigenetic mechanisms by which environment influences genetic expression and which mediate the gene-environment interaction.

Recent progress in research on the distribution and function of NUCB2/nesfatin-1 in peripheral tissues

Nesfatin-1 is a polypeptide derived from the posttranslational processing of the N-terminal fragment of nucleobindin 2 (NUCB2), that was originally identified as an anorexigenic hypothalamic neuropeptide. A number of reports have recently shown that NUCB2/nesfatin-1 is widely expressed in various peripheral tissues, including those of the gastrointestinal tract where it may participate in various pathophysiological processes. One of its roles may be regulation of energy homeostasis. As a result, nesfatin-1 may be a novel target for exploring the underlying mechanisms and the treatment of metabolic syndromes.