Leptin Receptor Gene Expression Research Articles

Ameliorative effects of zinc supplementation on cognitive function and hippocampal leptin signaling pathway in obese male and female rats

Obesity has been associated with cognitive impairments, increasing the probability of developing dementia. Recently, zinc (Zn) supplementation has attracted an increasing attention as a therapeutic agent for cognitive disorders. Here, we investigated the potential effects of low and high doses of Zn supplementation on cognitive biomarkers and leptin signaling pathway in the hippocampus of high fat diet (HFD)-fed rats. We also explored the impact of sex difference on the response to treatment. Our results revealed a significant increase in body weight, glucose, triglycerides (TG), total cholesterol (TC), total lipids and leptin levels in obese rats as compared to controls. HFD feeding also reduced brain-derived neurotrophic factor (BDNF) levels and increased acetylcholinesterase (AChE) activity in the hippocampus of both sexes. The low and high doses of Zn supplementation improved glucose, TG, leptin, BDNF levels and AChE activity in both male and female obese rats compared to untreated ones. Additionally, downregulated expression of leptin receptor (LepR) gene and increased levels of activated signal transducer and activator of transcription 3 (p-STAT3) that observed in hippocampal tissues of obese rats were successfully normalized by both doses of Zn. In this study, the male rats were more vulnerable to HFD-induced weight gain, most of the metabolic alterations and cognition deficits than females, whereas the female obese rats were more responsive to Zn treatment. In conclusion, we suggest that Zn treatment may be effective in ameliorating obesity-related metabolic dysfunction, central leptin resistance and cognitive deficits. In addition, our findings provide evidence that males and females might differ in their response to Zn treatment.

Brain glucose hypometabolism and hippocampal inflammation in Goto-Kakizaki rats.

Brain glucose hypometabolism and neuroinflammation are early pathogenic manifestations in neurological disorders. Neuroinflammation may also disrupt leptin signaling, an adipokine that centrally regulates appetite and energy balance by acting on the hypothalamus and exerting neuroprotection in the hippocampus. The Goto-Kakizaki (GK) rat is a non-obese type 2 diabetes mellitus (T2DM) animal model used to investigate diabetes-associated molecular mechanisms without obesity jeopardizing effects. Wistar and GK rats received the maintenance adult rodent diet. Also, an additional control group of Wistar rats received a high-fat and high-sugar diet (HFHS) provided by free consumption of condensed milk. All diets and water were provided ad libitum for eight weeks. Brain glucose uptake was evaluated by 2-deoxy-2-[fluorine-18] fluoro-D-glucose under basal (saline administration) or stimulated (CL316,243, a selective β3-AR agonist) conditions. The animals were fasted for 10-12 h, anesthetized, and euthanized. The brain was quickly dissected, and the hippocampal area was sectioned and stored at -80°C in different tubes for protein and RNA analyses on the same animal. GK rats exhibited attenuated brain glucose uptake compared to Wistar animals and the HFHS group under basal conditions. Also, the hippocampus of GK rats displayed upregulated leptin receptor, IL-1β, and IL-6 gene expression and IL-1β and the subunit of the transcription factor NF-κB (p-p65) protein expression. No significant alterations were detected in the hippocampus of HFHS rats. Our data indicated that a genetic predisposition to T2DM has significant brain deteriorating features, including brain glucose hypometabolism, neuroinflammation, and leptin signaling disruption in the hippocampal area.

Greater Body Fatness Is Associated With Higher Protein Expression of LEPR in Breast Tumor Tissues: A Cross-Sectional Analysis in the Women's Circle of Health Study.

BackgroundThe mechanisms underlying the association of overall and central body fatness with poorer breast cancer outcomes remain unclear; altered gene and/or protein expression of the adipokines and their receptors in breast tumors might play a role.MethodsIn a sample of Black and White women with primary invasive breast cancer, we investigated associations of body mass index (BMI), waist circumference, hip circumference, waist-to-hip ratio (WHR), fat mass index (FMI), and percent body fat with protein expression (log-transformed, n = 722) and gene expression (log2-transformed, n = 148) of leptin (LEP), leptin receptor (LEPR), adiponectin (ADIPOQ), and adiponectin receptors 1 and 2 (ADIPOR1, ADIPOR2). Multivariable linear models, adjusting for race, menopausal status, and estrogen receptor status, were used to assess these associations, with Bonferroni correction for multiple comparisons.ResultsIn multivariable models, we found that increasing BMI (β = 0.0529, 95% CI: 0.0151, 0.0906) and FMI (β = 0.0832, 95% CI: 0.0268, 0.1397) were associated with higher LEP gene expression, corresponding to 34.5% and 38.3% increases in LEP gene expression for a standard deviation (SD) increase in BMI and FMI, respectively. Increasing BMI (β = 0.0028, 95% CI: 0.0011, 0.0045), waist circumference (β = 0.0013, 95% CI: 0.0005, 0.0022), hip circumference (β = 0.0015, 95% CI: 0.0007, 0.0024), and FMI (β = 0.0041, 95% CI: 0.0015, 0.0067) were associated with higher LEPR protein expression. These associations equate to 16.8%, 17.6%, 17.7%, 17.2% increases in LEPR protein expression for a 1-SD increase in BMI, waist circumference, hip circumference, and FMI, respectively. Further, these associations were stronger among White and postmenopausal women and ER+ cases; formal tests of interaction yielded evidence of effect modification by race. No associations of body fatness with LEP protein expression, LEPR gene expression, or protein or gene expression of ADIPOQ, ADIPOR1, and ADIPOR2 were found.ConclusionsThese findings support an association of increased body fatness – beyond overall body size measured using BMI – with higher LEP gene expression and higher LEPR protein expression in breast tumor tissues. Clarifying the impact of adiposity-related adipokine and adipokine receptor expression in breast tumors on long-term breast cancer outcomes is a critical next step.

Effects of trans-Fatty Acid on Lipoproteins-a, Oxidative Status and Expression of Leptin and Leptin Receptor Genes in Albino Rats

High consumption of trans-fatty acids (TFAs) linked with obesity, disorders of lipoproteins, type 2 Diabetes Mellitus (T2DM), risk factors of coronary heart disease, and development of atherosclerosis. The intent of our trials was to assess the possible bad impact of TFAs on the lipid status and focusing on characterizing the physiological alters in an animal model comparing with cis fatty acids. Sixty male albino rats, with nearly similar average weight 170±5wereassignedinto 4 main groups (15 rats per group) and kept on a standard diet set for 12 weeks. All groups received different diet treatment for successive 12 weeks. Group A: control group received a conventional diet, group B received a diet contained 360 gm TFAs inform of partially hydrogenated vegetable oil (PHVO) l kg of diet, group C was fed a High Fat Diet (HFD) contained 360 gm beef tallow l kg of diet for, and group D received a diet containing 360 gm linseed oil l kg of diet. Both feeding of TFAs and HFD resulted in a marked increase in the body weight in reach to the obesity grade with a significant increase (P≤0.05) in leptin and leptin receptor gene expression. Also, a significant increase in Malondialdehyde (MDA) and Lipoprotein-a (Lp-a) and a marked decrease in total antioxidant capacity (TAC). It could be concluded that TFAs induce combined increased body weight, with imbalance in oxidative stress, dyslipidemia, and elevated atherogenic Lipoprotein-a may be leading to development of atherosclerosis and coronary heart disease.

Determinants of placental leptin receptor gene expression and association with measures at birth

IntroductionThe leptin signalling pathway is important in metabolic health during pregnancy. However, few studies have investigated the determinants and extent of leptin receptor gene (LEPR) expression in the placenta, nor the relationship with infant health in early life. Here, we investigate the genetic and maternal in utero determinants of placental LEPR expression, and whether this expression is linked to anthropometric and inflammatory measures at birth in healthy newborns in the Barwon Infant Study. MethodsPlacental LEPR expression was measured using RT-qPCR (n = 854 placentae). Associations between genetic variation in LEPR, maternal in utero factors, measures at birth and placental LEPR expression were assessed using multivariable linear regression modelling. ResultsWe found that the genotype at two intronic SNPs, rs9436301 and rs9436746, was independently associated with placental LEPR expression. Maternal pre-pregnancy body mass index, gestational diabetes mellitus, weight gain and smoking in pregnancy were not associated with LEPR expression. Placental LEPR expression was negatively associated with high sensitivity C-Reactive Protein in umbilical cord blood, which persisted after adjustment for potential confounders. DiscussionOverall, our findings suggest that genetic variation in LEPR plays a key role in regulating placental LEPR expression, which is in turn is associated with inflammatory markers in cord blood at birth. Further studies encompassing other aspects of leptin signalling are warranted to understand if these relationships are causal and have health implications.

Detection of polymorphisms in the bovine leptin receptor gene affects fat deposition in two Chinese beef cattle breeds.

Leptin receptor (LEPR) gene play a pivotal role in the regulation of fat deposition and energy homeostasis. This study investigated the presence and frequency of polymorphisms of bovine LEPR gene and determine whether the polymorphisms are associated with the fat deposition in two Chinese beef cattle breeds. Quantitative real-time polymerase chain reactions identified that the expression of LEPR gene was highest in the liver and subcutaneous fat. Four single nucleotide polymorphisms (SNPs) were identified including g.24169C>T, g.24256T>A, g.24267 G>C and g.24413T>A. A greater backfat thickness was associated with the AA genotype of g.24256T>A compared to the TT genotype. A greater intramuscular fat content was associated with the GG genotype of g.24267 G>C compared to the CC genotype. Both g.24169C>T and g.24413T>A were not correlated with fat deposition. These results indicated that the SNP g.24256T>A and g.24267 G>C of LEPR gene may be useful markers for genetic improvement of fat deposition in Chinese beef cattle breeds.

The energy budget and fat accumulation in striped hamsters (Cricetulus barabensis) during post-lactation

Adaptive adjustments of energy intake and body fat play an important role in allowing animals' to meet the energy demands of thermoregulation during cold conditions and reproduction. Body fat is usually metabolized during lactation, which is one of the most energetically demanding activities of female mammals, however the effect of this on the energy budget and body fat regulation after lactation remains unclear. We compared the energy intake and body fat of female striped hamsters (Cricetulus barabensis) fed either a high-fat or low-fat diet for 21 days after the end of lactation (post-lactation, PL) to those of virgin controls. Serum leptin levels and the expression of hypothalamic orexigenic and anorexigenic neuropeptide genes were also measured and compared. Although lactating females consumed significantly more food, they had significantly lower body fat than virgin controls. The energy intake and body fat levels of the PL females were, however, significantly higher than those of virgin females. This was particularly true for the PL females that were fed high-fat diet. These females had significantly higher serum leptin concentrations, but lower hypothalamic leptin receptor gene expression, than virgin females. Neither orexigenic nor anorexigenic neuropeptide levels in the hypothalamus differed significantly between the PL and virgin females. This suggests that a negative energy balance during lactation drives fat accumulation after lactation. Furthermore, leptin resistance may occur after the end of lactation, causing females to consume more food, and accumulate more fat, than virgin females.

Abstract C063: Associations of leptin and leptin receptor protein and gene expression with breast cancer clinicopathologic features

Abstract The adipokine, leptin (LEP) and its receptor (leptin receptor, LEPR), are hypothesized to play a role in breast cancer (BrCa) outcomes disparities. The objective of this study was to address the gaps in knowledge regarding the epidemiologic associations of LEP and LEPR protein and gene expression with breast cancer clinicopathologic features (namely, estrogen receptor [ER] status, and tumor grade, stage, size, and subtype). In the Women's Circle of Health Study, we used immunohistochemistry to assess protein expression in breast tumor tissue microarrays among a sample of 711 early stage BrCa cases. LEP and LEPR protein expression was scored semiquantitatively by a board-certified pathologist and we used NanoString digital, multiplexed assays to quantitatively assess gene expression of these biomarkers. Multivariable-adjusted logistic regression models were used to examine the associations of interest. Compared to ER+, LEP protein expression was lower (OR 0.54, 95% CI 0.30, 1.00), and LEPR protein (OR 3.95, 95% CI 2.02, 7.71) and gene expression (OR 1.003, 95% CI 1.001, 1.005) were higher among ER- BrCa cases. Compared to well/moderately differentiated tumors, LEPR protein (OR 2.46, 95% CI 1.40, 4.31) and gene expression (OR 1.002, 95% CI 1.000, 1.003) were higher among poorly differentiated tumors. Compared to luminal A, LEP protein expression was higher among non-luminal HER2-expressing (OR 3.34, 95% CI 1.20, 9.32) and TNBC subtypes (OR 2.02, 95% CI 1.00, 4.08), LEPR protein expression was lower among non-luminal HER2-expressing (OR 0.39, 95% CI 0.16, 0.94) and TNBC (OR 0.28, 95% CI 0.13, 0.57), and LEPR gene expression was lower in TNBC (OR 0.997, 95% CI 0.995, 0.999). LEP gene expression and LEPR protein and gene expression were inversely associated with tumor size (P-values <0.05). No major associations were observed between LEP and LEPR expression profiles and tumor stage. These findings suggest that LEP and LEPR protein and gene expression in the breast tumor microenvironment may serve as biomarkers contributing to interindividual differences in BrCa prognostic indicators and are important for understanding tumor heterogeneity and outcomes disparities. Funding: This study was supported by grants from the National Cancer Institute (K01CA193527, P01CA151135, R01CA100598, R01CA185623). Tumor samples were received, processed and tracked under the auspices of the Roswell Park Comprehensive Cancer Center DataBank and BioRepository Shared Resource, supported by P30CA16056 with support from the Breast Cancer Research Foundation to CBA. This work was also supported by the Biomedical Informatics and the Biospecimen Repository and Histopathology Service shared resources of Rutgers Cancer Institute of New Jersey, supported by P30CA072720. Citation Format: Adana A.M. Llanos, Baichen Xu, Bo Qin, Wenjin Chen, Marina A. Chekmareva, Lei Cong, Chi-Chen Hong, Song Yao, Christine B. Ambrosone, Elisa V. Bandera, Kitaw Demissie. Associations of leptin and leptin receptor protein and gene expression with breast cancer clinicopathologic features [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C063.

Maternal obesity modulates sexually dimorphic epigenetic regulation and expression of leptin receptor in offspring hippocampus

Maternal obesity during pregnancy is associated with a greater risk for obesity and neurodevelopmental deficits in offspring. This developmental programming of disease is proposed to involve neuroendocrine, inflammatory, and epigenetic factors during gestation that disrupt normal fetal brain development. The hormones leptin and insulin are each intrinsically linked to metabolism, inflammation, and neurodevelopment, which led us to hypothesise that maternal obesity may disrupt leptin or insulin receptor signalling in the developing brain of offspring. Using a C57BL/6 mouse model of high fat diet-induced maternal obesity (mHFD), we performed qPCR to examine leptin receptor (Lepr) and insulin receptor (Insr) gene expression in gestational day (GD) 17.5 fetal brain. We found a significant effect of maternal diet and offspring sex on Lepr regulation in the developing hippocampus, with increased Lepr expression in female mHFD offspring (p < 0.05) compared to controls. Maternal diet did not alter hippocampal Insr in the fetal brain, or Lepr or Insr in prefrontal cortex, amygdala, or hypothalamus of female or male offspring. Chromatin immunoprecipitation revealed decreased binding of histones possessing the repressive histone mark H3K9me3 at the Lepr promoter (p < 0.05) in hippocampus of female mHFD offspring compared to controls, but not in males. Sex-specific deregulation of Lepr could be reproduced in vitro by exposing female hippocampal neurons to the obesity related proinflammatory cytokine IL-6, but not IL-17a or IFNG. Our findings indicate that the obesity-related proinflammatory cytokine IL-6 during pregnancy leads to sexually dimorphic changes in the modifications of histones binding at the Lepr gene promoter, and concomitant changes to Lepr transcription in the developing hippocampus. This suggests that exposure of the fetus to metabolic inflammatory molecules can impact epigenetic regulation of gene expression in the developing hippocampus.

Effects of Lactobacillus acidophilus and Bifidobacterium bifidum probiotics on the serum biochemical parameters, and the vitamin D and leptin receptor genes on mice colon cancer.

Objective(s):The preclinical reports have shown that specific probiotics like Bifidobacterium bifidum (B. bifidum) and Lactobacillus acidophilus (L. acidophilus) can be applied as the biotherapeutic agents in the inhibition or therapy of colorectal cancer via the modification of gut bacteria. In the previous studies, we have assessed the impact of L. acidophilus and B. bifidum probiotics on gut bacteria concentration and also their chemo-protective impact on mice colon cancer. In the following, we assessed the effects of these probiotics on the gene expression of vitamin D receptor (VDR) and the leptin receptor (LPR) and the serum biochemical parameters on mice colon cancer. Materials and Methods:Thirty-six male BALB/c mice were equally shared into 4 groups; (i) health with routine dietary foods without any treatment, (ii) azoxymethane (AOM)-induced mice colon cancer with common dietary foods, (iii) and (iv) AOM-induced mice colon cancer with oral consumption of L. acidophilus and B. bifidum (1×109 cfu/g) for 5 months, respectively. Then, the serum total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), alanine transaminase, alkaline phosphatase, and albumin and also VDR and LPR genes expression were evaluated. Results:Oral consumption of L. acidophilus and B. bifidum probiotics significantly decreased the triglycerides, alkaline phosphatase, LDL, and also the VDR and LPR gene expression in mice colon cancer (P<0.005).Conclusion: L. acidophilus and B. bifidum probiotics with the modification of the biochemical parameters and the expression of the VDR and LPR genes can play a key role in the protection of mouse colon cancer.

491-P: Obesity-Induced Kidney Damage Is Attenuated by Genetic Deletion of miR-379 in Mice

Obesity is significantly associated with diabetes and related complications like kidney disease. Evidence shows dysregulation of certain non-coding RNAs including microRNAs can accelerate diabetic kidney disease (DKD). Recently, we found that miR-379 and its host transcript long non-coding RNA, lncMGC, were regulated by endoplasmic reticulum (ER) stress in glomerular cells, and lncMGC could promote features of DKD in mice. In this study, we examined the in vivo role of miR-379 in obesity-induced kidney disease by testing miR-379-knockout (KO) mice generated by CRISPR-Cas9 editing. Male (M) and female (F) mice were fed with control diet, or high fat diet (HFD) for 24 weeks to induce obesity in wild type (WT) and miR-379KO mice. Kidney function was examined by measuring urinary albumin and creatinine. Expression of miR-379 target genes (Edem3, Fis1), Leptin receptor (LepR) and profibrotic genes (Tgf-β1, Ctgf, Col4a1, Col1a2) was measured in isolated glomerular cells. Cortical sections were stained for histopathology. Blood glucose levels were similar in miR379KO-HFD and WT-HFD. miR379KO-HFD-F mice exhibited significantly lower body weight and body fat composition versus WT-HFD-F. Hyperinsulinemia observed in WT-HFD-F mice was attenuated in miR379KO-HFD-F. LepR expression was significantly decreased in WT-HFD-F but not miR379KO-HFD-F mice relative to controls. Increased expression of profibrotic genes, glomerular hypertrophy and interstitial fibrosis observed in WT-HFD-F were significantly attenuated in miR379KO-HFD-F mice. Similar to females, male miR-379KO-HFD-M mice showed significant reductions in glomerular hypertrophy, fibrosis and ER stress markers vs. WT-HFD-M. However, unlike females, miR379KO-HFD-M mice did not display reduced body weight compared to WT-HFD-M. These results suggest miR-379 deficiency protects mice from HFD-induced obesity and kidney injury, with some gender differences. miR-379 inhibition may be a novel therapy for HFD-induced metabolic disorders. Disclosure M. Abdollahi: None. M. Kato: None. R. Tunduguru: None. L.L. Lanting: None. R. Natarajan: None. Funding National Institutes of Health

Effect of Feed Restriction and Photoperiod on Reproduction and LEPR, MELR mRNA Expression of Layers

ABSTRACT Photoperiod and nutrition are major factors that affect the reproductive efficiency particularly in female animals. In this study we examined the interaction of photoperiod and food restriction on growth, sexual maturation and receptor mRNA expressions of leptin, melatonin, and estrogen in abdominal fat and the ovary of pullets. There were no interaction effects between photoperiod and feeding level on body weight, abdominal fat weight, ovary weight at both 14 wk and 18 wk. Abdominal fat weight of feed restriction group was significantly lower compared with the control group at the age of 14 wk, 18 wk, and age of the first egg (AFE) (p<0.05). Ovary LEPR (Leptin receptor) gene expression showed an interaction effect of the first egg. Restricted feeding significantly inhibited ovary ER (Estrogen receptor), LEPR and MELR1B (Melatonin 1B receptor) gene expression at 14 wk, 18 wk and the first egg. At 14-week-old, abdominal fat LEPR gene expression was significantly lower in long photoperiod group compared with the short photoperiod group. At the first egg, short photoperiod and feed restriction group reduced abdominal fat LEPR gene expression. The results indicated that the reproductive activity of pullets is sensitive to feed intake and photoperiod. Feed restriction down regulated the ER, LEPR, MELR1A (Melatonin 1A receptor) and MELR1B mRNA expression of the ovary at 14 wk, 18wk and AFE. Long photoperiod enhanced the LEPR, MELR1A and MELR1B mRNA expression of abdominal fat at AFE.

Expression patterns of candidate genes reflecting the growth performance of goats subjected to heat stress

The study is an attempt to elucidate the molecular mechanisms governing growth performance during heat stress in goats. The primary objective of the study was to establish the influence of heat stress on the expression patterns of different growth related genes in Malabari goats. The study was conducted for a period of 45days in 12 Malabari goats randomly allocated into two groups: MC (n = 6; Malabari control) and MHS (n = 6; Malabari heat stress). At the end of study period, all 12 animals were slaughtered and their liver tissues were collected for gene expression and histopathological studies. The temperature-humidity-index (THI) inside the shed (74.9) proved that the animals were not stressed while in the outside environment (86.5) the animals were extremely distressed. The hepatic growth hormone (GH), growth hormone receptor (GHR), insulin-like growth factor-1 (IGF-1), leptin (LEP) and leptin receptor (LEPR) gene expression patterns were significantly (P < 0.05) lower in heat stress group as compared to the control group animals. In addition, negative correlation (P < 0.05) was also established between THI and all the growth related gene expression in the study. The hepatic histopathological section showed more fatty and degenerative changes (P < 0.05) in hepatocytes in MHS group as compared to MC group. The study offers the first thorough insight into the expression patterns of different growth related genes during heat stress exposure in goats. Further, the study established GH, GHR, IGF-1, LEP, LEPR genes to be the ideal markers to reflect growth potential in Malabari goats.

Effect and interactions of Pueraria-Rehmannia and aerobic exercise on metabolic inflexibility and insulin resistance in ovariectomized rats fed with a high-fat diet

Due to limitations of estrogen replacement therapy, life style interventions have received a growing attention. This study aimed to determine whether Pueraria-Rehmannia (PR) and/or aerobic exercise (Ex) could reduce cardiometabolic dysfunction in an ovariectomized/high-fat diet rat model. PR ameliorated circulating levels of total cholesterol, LDL/HDL ratio, and leptin. It reduced fat mass, fat size, leptin gene expression, and macrophage infiltration in adipocytes. PR maintained leptin receptor gene expression in muscle tissues. It stimulated insulin-mediated GLUT4 translocation in muscle and adipose tissues. PR plus Ex resulted in further improvement in glucose homeostasis by stimulating Akt-mediated insulin receptor expression in the liver. Moreover, PR and/or Ex reduced vascular wall thickness and intracellular cell adhesion molecule-1 production without causing uterotrophic effect. These results suggest that PR and Ex may exert synergistic effects in modifying metabolic dysfunctions and insulin resistance, thus suppressing cardiovascular risks in postmenopausal women through restoring insulin sensitivity and attenuating inflammation.

Hypothalamic Pomc‐deficiency Impairs the Function of Leptin to Decrease Food Intake and Bodyweight

Proopiomelanocortin (Pomc) in the arcuate nucleus (Arc) of the hypothalamus is necessary for normal energy homeostasis; therefore, its deficiency leads to obesity. We recently reported that ArcPomc‐rescue by genetic intervention prevents obesity in otherwise obesity‐destined ArcPomc‐knockout (KO) mice. However, the efficiency of ArcPomc‐rescue to normalize body weight (BW) was contingent on the magnitude of obesity at the time of genetic intervention. To dissect the molecular mechanism(s) responsible for that observation, we hypothesized that ArcPomc‐rescue mediated reversal of obesity is linked to the function of leptin to reduce BW and food intake (FI). To test our hypothesis, we performed a longitudinal study during which we assessed BW, FI, plasma leptin levels and leptin sensitivity in the same set of ArcPomc‐KO mice when they were obese, weight‐matched to WT mice by calorie restriction, and after ArcPomc rescue. ArcPomc was rescued in the weight‐matched mice by tamoxifen‐inducible Cre recombinase technology. We found that obese KO mice exhibited significantly higher plasma leptin levels (68 ±4.1 vs. 5.6 ±0.4 ng/ml), which were reduced by 78% in the weight‐matched group (14.5 ±1.2 ng/ml) but still remained higher, relative to WT group (P&lt;0.01). Moreover, leptin treatment did not reduce BW relative to saline‐group (Δ BW, 0.52 ±0.06 vs. 0.56 ±0.07 g/24 h when mice were obese; 0.8 ± 0.08 vs 0.6 ±0.07 g/24 h when mice were weight‐matched) and FI (Δ FI, 5.8 ±0.2 vs. 6.1 ±0.1 g/24 h when mice were obese; 6.0 ±0.1 vs. 6.2 ±0.1 g/24 h when mice were weight‐matched) in the KO mice at different stages of the longitudinal study. Remarkably, we found that ArcPomc‐rescue in the weight‐matched KO mice restored normal BW (32.6 ±1.0 g), FI (4.4 ±0.6 g), leptin levels (4.6 ±1.3 ng/ml) and sensitivity [Δ BW, −1.6 ±0.1 (leptin) vs. 0.01 ±0.06 (saline) g/24 h] in the mice that had a history of obesity. In contrast, mice that remained ArcPomc deficient regained massive obesity (BW: 68.4 ±1.5 g, P&lt;0.001) and hyperleptinemia (70.2 ±5.4 ng/ml, P&lt;0.001). To further confirm the association of hypothalamic Pomc with leptin action, we treated weight‐matched ArcPomc KO mice without a history of obesity with leptin. Intraperitoneal and intracerebroventricular leptin administration failed to reduce BW and FI in the KO mice. Interestingly, there was no change in hypothalamic leptin receptor gene expression; however, relative hypothalamic pSTAT3 levels after leptin administration were 20% lower in the KO mice compared to wildtype mice. Altogether, our study suggests that restoration of normal body weight and food intake in ArcPomc KO mice after ArcPomc‐rescue is linked with leptin sensitivity. Moreover, hypothalamic Pomc appears to mediate the function of leptin to control BW and FI. Therefore, stimulating hypothalamic Pomc signaling provides an alternative approach to treat obesity in face of leptin resistance.Support or Funding InformationNIH grants R01 DK066604 (to M.J.L.), R01 DK068400 (to M.J.L. and M.R.). NIH grants P30 DK020572 and P30 DK089503 to University of Michigan Animal Phenotyping and Chemistry Cores supported by the Michigan Diabetes Research Center and the Michigan Nutrition and Obesity Research Center

Reduced Perinatal Leptin Availability May Contribute to Adverse Metabolic Programming in a Rat Model of Uteroplacental Insufficiency.

Leptin availability in perinatal life critically affects metabolic programming. We tested the hypothesis that uteroplacental insufficiency and intrauterine stress affect perinatal leptin availability in rat offspring. Pregnant rats underwent bilateral uterine vessel ligation (LIG; n = 14), sham operation (SOP; n = 12), or no operation (controls, n = 14). Fetal livers (n = 180), placentas (n = 180), and maternal blood were obtained 4 hours (gestational day [E] 19), 24 hours (E20), and 72 hours (E22) after surgery. In the offspring, we took blood samples on E22 (n = 44), postnatal day (P) 1 (n = 29), P2 (n = 16), P7 (n = 30), and P12 (n = 30). Circulating leptin (ELISA) was significantly reduced in LIG (E22, P1, P2) and SOP offspring (E22). Postnatal leptin surge was delayed in LIG but was accelerated in SOP offspring. Placental leptin gene expression (quantitative RT-PCR) was reduced in LIG (E19, E20, E22) and SOP (E20, E22). Hepatic leptin receptor (Lepr-a, mediating leptin degradation) gene expression was increased in LIG fetuses (E20, E22) only. Surprisingly, hypoxia-inducible factors (Hif; Western blot) were unaltered in placentas and were reduced in the livers of LIG (Hif1a, E20; Hif2a, E19, E22) and SOP (Hif2a, E19) fetuses. Gene expression of prolyl hydroxylase 3, a factor expressed under hypoxic conditions contributing to Hif degradation, was increased in livers of LIG (E19, E20, E22) and SOP (E19) fetuses and in placentas of LIG and SOP (E19). In summary, reduced placental leptin production, increased fetal leptin degradation, and persistent perinatal hypoleptinemia are present in intrauterine growth restriction offspring, especially after uteroplacental insufficiency, and may contribute to perinatal programming of leptin resistance and adiposity in later life.

Association of expressions and gene polymorphisms of leptin receptor with breast cancer

Objective To evaluate the association of expressions and gene polymorphism of leptin receptor (LEPR) in breast cancer with tumorigenesis, development and clinicopathologic factors. Methods The immunohistochemical method and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) were used to evaluate LEPR expressions and LEPR Gln223Arg polymorphism in 150 cases with breast cancer, 80 cases with benign breast lesions, 50 cases with corresponding normal breast tissue and 128 healthy controls. Results The expression rate of LEPR genes in breast cancer tissues was significantly higher than that in benign breast lesions and that in corresponding normal breast tissues [70.67 % (106/150) vs 56.25 % (45/80) vs 44.00 % (22/50), P 0.05). The frequencies of alleles genes in breast cancer patients (G and A) were 78.33 % (235 cases) and 21.67 % (65 cases), and the differences were statistically significant compared with those in the benign disease group or in healthy control group (χ2 = 12.52, P= 0.001). The positive expression rate of LEPR gene in patients with lymph node metastasis was 87.8 %, which was higher than that in patients with no lymph node metastasis (60.2 %) (P= 0.02). According to the results of multivariable analyses, high expression of LEPR gene, LEPR Gin223Arg gene polymorphisms and increased waist-hip ratio (WHR) were risk factors for breast cancer (all OR > 1). Conclusion High expression of LEPR, LEPR Gln233Arg polymorphism and the elevated WHR may be correlated with breast cancer. Key words: Breast neoplasms; Leptin receptor; Genes; Polymorphism, single nucleotide

Copy number variations at LEPR gene locus associated with gene expression and phenotypic traits in Chinese cattle

Current evidences show that copy number variations (CNVs) are linked to complex phenotypic traits. Leptin receptor (LEPR) gene plays a critical role in energy homeostasis and fat development and re-sequencing of the cattle genome revealed the CNV region (herein referred to as "I3 DNA") within the LEPR intron 3. In the present study, we qualified copy numbers of I3 DNA within LEPR gene in four cattle breeds (Qinchuan, Nanyang, Jinnan and Xianan) by quantitative PCR, and explored their impacts on LEPR gene expression and phenotypic traits in Qinchuan and Nanyang cattle. The results showed that more individuals in Nanyang are with loss of the I3 DNA copy number than that in the others. Additionally, I3 DNA CNVs exhibited a significant negative correlation with LEPR gene expression (P < 0.05). Association analysis showed that gain/normal copy number types performed better traits of body weight, body height and body length than the loss type in Nanyang. To the best of our knowledge, this is the first evidence of the association between LEPR CNVs and cattle traits, and this may help deep understanding of the function of CNVs which may be promising markers for beef cattle breeding and genetics.

Leptin in the canine uterus and placenta: possible implications in pregnancy

BackgroundLeptin (Lep) is known for its involvement in the regulation of reproductive functions. It is important for uterine receptivity, implantation, placental growth and maternal energy homeostasis in several species, but Lep’s function in the pregnant dog has not been investigated.MethodsPregnant bitches were ovariohysterectomized at pre-implantation, post-implantation, mid-gestation and prepartum luteolysis. Two additional groups were treated with aglepristone in mid-gestation, and ovariohysterectomized 24 or 72 h later. Lep and leptin receptor (LepR) gene expression was detected by semi-quantitative real-time PCR in pre-implantation and inter-placental uterine sections (Ut) and in utero-placental compartments (Ut/Pl). Immunohistochemistry and in situ hybridization (ISH) were performed for Lep and LepR protein and mRNA localization. Parametric one-way ANOVA, paired t-test and Wilcoxon signed-rank test were used for statistical analysis.ResultsIn the Ut/Pl, Lep expression was higher at post-implantation and prepartum luteolysis than at mid-gestation, while in the Ut, Lep mRNA levels did not change during pregnancy. LepR expression in the Ut/Pl was up-regulated at prepartum luteolysis compared to the earlier stages. In the Ut, highest LepR mRNA was found at pre- and post-implantation. LepR expression was down-regulated in the Ut/Pl compared to the Ut at post-implantation and at mid-gestation. Aglepristone treatment resulted in a decrease of Lep mRNA levels from 24 to 72 h in the Ut without concomitant changes in the Ut/Pl or in LepR levels. Lep and LepR immunoreactivities were strong in the luminal and glandular epithelium in the Ut with abundant LepR signals in the subepithelial stroma. In the Ut/Pl, fetal trophoblasts stained stronger for Lep and LepR than decidual cells, and signals for both proteins were also detected in the glandular chambers. The myometrium, blood vessel media, and sporadically also the endothelium stained for Lep and LepR. ISH showed similar signal distribution in the Ut and Ut/Pl.ConclusionsLep and LepR are differentially expressed in the canine uterus and placenta during pregnancy, and their presence in various cell types indicates paracrine/autocrine roles. The Lep signaling system may be one of the pathways involved in feto-maternal cross-talk, implantation and maintenance of pregnancy, and may have a regulatory role around parturition.

Relationship between the level of hippocampal leptin receptor gene expression and learning performance in diabetic rats.

Diabetes mellitus may be associated with impaired cognitive function. Decreased peripheral glucose regulation was associated with decreased general cognitive performance, memory impairments, and atrophy of the hippocampus, a brain area that is key for learning and memory. Leptin that is a peptide hormone, acts in the hippocampus where it facilitates the induction of long-term potentiation and enhances NMDA receptor mediated transmission. The aim of the present study is to investigate possible relationship between the hippocampal leptin receptor gene expression and learning performance in streptozotocin (STZ) induced diabetic rats. In this study was conducted on a total of 40 Winstar albino female rats, including a control group consisting of 20 rats and experimental group comprising of 20 rats in which diabetes was induced by means of STZ administration. Leptin receptor gene expression was detected in hippocampal samples by using real time-PCR. According to the evaluation, the learning performance of rats with induced diabetes was found to be same throughout the first 3 days after STZ in comparison to the control group rats. End of the 45 days the learning performance of the control group was found to be better than the diabetic group (p<0.05). Hipocampal leptin receptor expression was found lower in diabetic group than the control group (p<0.05). The results provide evidence that leptin receptor gene may related to learning performance in diabetic rats. Further, detailed studies are needed to address the exact role of leptin and related molecules in learning performance.