Carcinoma, Hepatocellular ; pathology ; Humans ; Leptin ; genetics ; Liver Neoplasms ; pathology ; RNA, Messenger ; genetics ; Receptors, Leptin ; genetics ; Tumor Cells, Cultured

To study the expression and distribution of neuropeptide Y (NPY) and long leptin receptor (OB-Rb) in the gastrointestinal tract of giant panda, samples of three animals were collected from the key laboratory for reproduction and conservation genetics of endangered wildlife of Sichuan province, China conservation and research center for the giant panda. Paraffin sections of giant panda gastrointestinal tissue samples were observed using hematoxylin-eosin staining (HE) and strept actividin-biotin complex immunohistochemical staining (IHC). The results show that the intestinal histology of three pandas was normal and no pathological changes, and there were rich single-cell and multi-cell mucous glands, long intestinal villi and thick muscularis mucosa and muscle layer. Positive cells expressing NPY and OB-Rb were widely detected in the gastrointestinal tract by IHC methods. NPY positive nerve fibers and neuronal cell were widely distributed in submucosal plexus and myenteric plexus, especially in the former. They were arranged beaded or point-like shape. NPY positive cells were observed in the shape of ellipse and polygon and mainly located in the mucous layer and intestinal glands. OB-Rb positive cells were mainly distributed in the mucous layer and the laminae propria, especially the latter. These results confirmed that NPY and OB-Rb are widely distributed in the gut of the giant panda, which provide strong reference for the research between growth and development, digestion and absorption, and immune function.
Animals ; China ; Intestines ; metabolism ; Neuropeptide Y ; genetics ; metabolism ; Receptors, Leptin ; genetics ; metabolism ; Ursidae ; genetics ; metabolism

Obesity has become a severe public health problem across the world, and seriously affects the health and life quality of human beings. Here we generated lepr and mc4r mutant zebrafish via the CRISPR/Cas9 technique, and performed morphological and functional characterizations of those mutants. We observed that there was no significant phenotypic difference between homozygous mutants and wild-type controls before 2.5 months post-fertilization (mpf). However, the adult leprand mc4rindividuals displayed increased food intake, heavier weight, and higher body fat percentage, the characteristics of obesity phenotypes. Blood glucose test showed that overfeeding induced significantly impaired glucose tolerance in adult leprand mc4rzebrafish. Furthermore, we analyzed 76 energy metabolism-related transcripts in leprand mc4rzebrafish livers by using real-time RT-PCR, and compared the results with the published microarray data of Lepmouse livers, and found that the changes in the expression of insulin/IGF signaling (IIS) pathway genes in leprzebrafish and Lepmouse were positively correlated, suggesting that the IIS pathway maintains functional conservation between zebrafish and mammals during the evolution of the obesity-regulating molecule network.
Animals ; CRISPR-Cas Systems ; Gene Knockout Techniques ; Insulin ; metabolism ; Leptin ; Mutation ; Obesity ; genetics ; Receptor, Melanocortin, Type 4 ; genetics ; Receptors, Leptin ; genetics ; Signal Transduction ; Zebrafish ; Zebrafish Proteins ; genetics

OBJECTIVETo investigate the association between Gln223Arg variant in leptin receptor (LEPR) gene and obesity.

METHODSThe subjects were from Yu county, Shanxi province, China. Data on cardiovascular risk factors was collected with questionnaire and their Gln223Arg variants in LEPR gene were genotyped. The relation between Gln223Arg variant in LEPR and obesity was analyzed.

RESULTSThe genotype frequencies of G. G, G. A and AA were 0.7679, 0.2171 and 0.015 respectively and the allele frequencies of G and A were 0.8764 and 0.1236. The distribution of genotype was in Hardy-Weinberg equilibrium (P = 0.934). The results of single factor analysis showed that the carriers with the Arg223 alleles had higher weight (63.2 kg vs. 61.9 kg; P= 0.0307) and body mass index (24.4 kg/rn vs. 24.1 kg/m2; P = 0.0898) than those noncarriers of these alleles. Results from multivariate analysis indicated that the carriers with the Arg223 alleles had higher body mass index (24.5 kg/m2 vs. 24.1 kg/m ;P= 0.0396) and prevalence of obesity (OR = 1.30, 95% CI: 0.957-1.767; P= 0.0935).

CONCLUSIONThese data indicated that Gln223Arg variant in LEPR gene was possibly associated with obesity, respectively.

Body Mass Index ; Body Weight ; China ; Genotype ; Humans ; Obesity ; genetics ; Receptors, Leptin ; genetics ; Risk Factors

Six 89bp primers were designed on the base of the cDNA sequence encoding the human leptin reported on the NCBI. The synthetic gene with 464bp encoding rhLep was obtained by SOE ( splicing by overlap extension) PCR. The expression vector pET22b(+)/rhLep was constructed and transformed into E. coli BL21 (DE3). The rhLep protein was expressed as inclusion bodies with the yield of more than 50% of total bacterial proteins after IPTG induction. The rhLep protein, which has a molecular weight about 16kD, was purified by Ni2+ affinity chromatography column and identified by SDS-PAGE. The MTT Assay shows that rhLep promotes EC304 cells growth at the low concentration of 10ng/mL to 30 ng/mL, and rhLep appears cytotoxic to EC304 cells with the high dose of 50ng/mL to 225ng/mL. The viability of EC304 cells decreases to 1.2% with the concentration of 225ng/mL of rhLep. The massive apoptosis of rhLep on EC304 cells is observed by AO-staining under fluorescent microscope. All these results would lay the foundation for the further study of its biological functions in vitro and in vivo.
Apoptosis ; drug effects ; Escherichia coli ; genetics ; Humans ; Leptin ; genetics ; pharmacology ; Recombinant Proteins ; biosynthesis ; isolation & purification ; pharmacology

OBJECTIVETo evaluate the association between serum level of leptin and leptin receptor gene (LEPR) polymorphism and patients with breast cancer.

METHODSLEPR G1n223Arg polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism in 94 patients with breast cancer and 128 healthy controls. The level of leptin were analyzed by enzyme linked immunosorbent assay.

RESULTSIn univariate regression analyses, we found serum level of leptin and LEPR Gin223Arg genotype polymorphism were significantly higrer than those of the controls (P < 0.05-0.001, respectively). Through multivariable analyses, we found that increased risk estimates for breast cancer were among those with leptin level (OR = 1.53, 95% CI: 1.13-2.07, P = 0.006), LEPR Gin223Arg genotype (OR = 4.87, 95%CI:1.30-18.22, P = 0.019), WHR (OR = 3.68, 95% CI: 1.34-10.11, P = 0.011).

CONCLUSIONResults from this study suggested that LEPR Gln233Agr polymorphism, the elevated WHR and serum level of leptin might be correlated with increased risk of breast cancer.

Breast Neoplasms ; blood ; genetics ; Enzyme-Linked Immunosorbent Assay ; Female ; Genetic Predisposition to Disease ; Humans ; Leptin ; blood ; Lipids ; blood ; Polymorphism, Genetic ; Receptors, Leptin ; genetics ; Risk

Animals ; Humans ; Leptin ; genetics ; physiology ; Liver Cirrhosis ; etiology ; RNA, Messenger ; analysis ; Receptors, Cell Surface ; analysis ; physiology ; Receptors, Leptin ; Transforming Growth Factor beta ; genetics ; Transforming Growth Factor beta1

INTRODUCTIONCommon obesity is a multi-factorial trait, contributed by the "obesogenic" environment of caloric abundance and increasing automation, sedentary lifestyle and an underlying genetic susceptibility. There have been major advances in the past decade in our understanding of the human weight regulation mechanism and pathogenesis of obesity, abetted by discoveries of genetic defects which lead to human obesity.

MATERIALS AND METHODSReports of genetic mutations causing obesity in humans and murine models were reviewed.

RESULTSHumans with genetic defects resulting in leptin deficiency, leptin receptor deficiency, proopiomelanocortin deficiency (POMC), and melanocortin 4 receptor (MC4R) deficiency developed severe obesity as the dominant phenotypic feature, though these are rare autosomal recessive conditions, except MC4R deficiency which is inherited in an autosomal co-dominant fashion. Common and rare variants of the POMC and melanocortin 3 receptor genes may be predisposing factors in the development of common obesity. Recent reports of human obesity associated with thyrosine kinase B (TrkB) defect and brain derived neurotrophic factor (BDNF) disruption, coupled with other murine studies, supported the role of BDNF/TrkB as effectors downstream of the melanocortin receptors.

CONCLUSIONDespite exciting discoveries of single gene mutations resulting in human obesity, most cases of obesity are likely the result of subtle interactions of several related genetic variants with environmental factors which favour the net deposition of calories as fat, culminating in the obese phenotype. The mechanisms of action of these genes in the development of obesity are now being examined, with the aim of eventually discovering a therapeutic intervention for obesity.

Animals ; Body Weight ; genetics ; Disease Models, Animal ; Humans ; Leptin ; genetics ; physiology ; Melanocortins ; genetics ; physiology ; Mice ; Mutation ; Obesity ; genetics

The prevailing model of osteology is that bones constantly undergo a remodeling process, and that the differentiation and functions of osteoblasts are partially regulated by leptin through different central hypothalamic pathways. The finding that bone remodeling is regulated by leptin suggested possible endocrinal effects of bones on energy metabolism. Recently, a reciprocal relationship between bones and energy metabolism was determined whereby leptin influences osteoblast functions and, in turn, the osteoblast-derived protein osteocalcin influences energy metabolism. The metabolic effects of bones are caused by the release of osteocalcin into the circulation in an uncarboxylated form due to incomplete gamma-carboxylation. In this regard, the Esp gene encoding osteotesticular protein tyrosine phosphatase is particularly interesting because it may regulate gamma-carboxylation of osteocalcin. Novel metabolic roles of osteocalcin have been identified, including increased insulin secretion and sensitivity, increased energy expenditure, fat mass reduction, and mitochondrial proliferation and functional enhancement. To date, only a positive correlation between osteocalcin and energy metabolism in humans has been detected, leaving causal effects unresolved. Further research topics include: identification of the osteocalcin receptor; the nature of osteocalcin regulation in other pathways regulating metabolism; crosstalk between nutrition, osteocalcin, and energy metabolism; and potential applications in the treatment of metabolic diseases.
Bone Remodeling/physiology ; Bone and Bones/*metabolism ; *Energy Metabolism ; Humans ; Leptin/metabolism ; Osteocalcin/genetics/*metabolism

Leptin, a peptide hormone secreted by adipocytes in proportion of the amount of energy stored in fat, plays a central role in regulating human energy homeostasis. In addition, leptin plays a significant permissive role in the physiological regulation of several neuroendocrine axes, including the hypothalamic-pituitary-gonadal, -thyroid, -growth hormone, and -adrenal axes. Decreased levels of leptin, also known as hypoleptinemia, signal to the brain a state of energy deprivation. Hypoleptinemia can be a congenital or acquired condition, and is associated with alterations of the aforementioned axes aimed at promoting survival. More specifically, gonadotropin levels decrease and become less pulsatile under conditions of energy deprivation, and these changes can be at least partially reversed through leptin administration in physiological replacement doses. Similarly, leptin deficiency is associated with thyroid axis abnormalities including abnormal levels of thyrotropin-releasing hormone, and leptin administration may at least partially attenuate this effect. Leptin deficiency results in decreased insulin-like growth factor 1 levels which can be partially ameliorated through leptin administration, and leptin appears to have a much more pronounced effect on the growth of rodents than that of humans. Similarly, adrenal axis function is regulated more tightly by low leptin in rodents than in humans. In addition to congenital leptin deficiency, conditions that may be associated with decreased leptin levels include hypothalamic amenorrhea, anorexia nervosa, and congenital or acquired lipodystrophy syndromes. Accumulating evidence from proof of concept studies suggests that leptin administration, in replacement doses, may ameliorate neuroendocrine abnormalities in individuals who suffer from these conditions.
Amenorrhea/metabolism ; Animals ; Female ; Humans ; Leptin/blood/deficiency/genetics/*metabolism ; Male ; Neurosecretory Systems/*metabolism