Protein tyrosine phosphatase 1B (PTP1B) has been considered as a promising therapeutic target for type 2 diabetes mellitus (T2DM) and obesity due to its key regulating effects in insulin signaling and leptin receptor pathways.
We present a 3-year-old male patient with severe early-onset obesity whose genetic analysis revealed a homozygous, novel, and pathogenic variant (c.1603+2T>C) in LEPR.
Protein tyrosine phosphatase 1B (PTP1B) is a major negative regulator of both the insulin and leptin receptor phosphorylation which impacts insulin sensitivity and hence is a major therapeutic target for the treatment of type 2 diabetes and obesity.
The central expression and function of leptin receptor B (LepRb) have been extensively studied during the past two decades; however, the mechanisms by which LepRb signaling dysregulation contributes to the pathophysiology of obesity remains unclear.
Endospanin 1 (Endo1), a protein encoded in humans by the same gene than the leptin receptor (ObR), and increased by diet-induced obesity, is an important regulator of ObR trafficking and cell surface exposure, determining leptin signaling strength.
Changes in Oxidized Low-Density Lipoprotein Rather Than in Paraoxonase1 are Associated with Changes in the Leptin/Leptin Receptor Ratio in Obese Children During Weight-Loss Therapy.
A spontaneous leptin receptor point mutation causes obesity and differentially affects leptin signaling in hypothalamic nuclei resulting in metabolic dysfunctions distinct from db/db mice.
Secondly, maternal obesity (in the absence of gestational diabetes) was associated with (i) elevated DNA methylation of the leptin promoter on fetal side only, (ii) hypomethylation of the adiponectin promoter on the maternal side only, (iii) significantly low levels of leptin receptor protein (albeit in the absence of differences in mRNA levels and promoter DNA methylation), (iv) significantly low levels of adiponectin receptor 1 mRNA expression on the maternal side only, and (v) elevated DNA methylation of the adiponectin receptor 2 promoter on the maternal side only.
Since leptin resistance is implicated in the pathogenesis of obesity, we herein report the effects of laparoscopic sleeve gastrectomy (LSG) on the serum levels of leptin and leptin receptor, in addition to its overall effect on leptin resistance.
LEPRrs1137101 GG genotype was related to reduced risk of obesity (odds ratio [OR] 0.26, 95% confidence interval [CI] 0.08-0.79; p = 0.018) and MetS (OR 0.36, 95% CI 0.15-0.88; p = 0.024), but it was not significant after Bonferroni correction for multiple tests as compared to the AA genotype (p > 0.01).
Thus, Cas9-generated Lep and Lepr KO mouse lines will be easier for genotyping, to maintain the lines, and to use for future obesity and diabetes research.
To further define the MC4R pathway and its potential impact on obesity, we tested associations between body mass index (BMI) and LoF mutation burden in the POMC, PCSK1, and LEPR genes in various populations.
Since leptin deficiency is associated with obesity and other metabolic abnormalities, we generated mice that lack the leptin receptor (LepRb) in cells of the myeloid linage (LysM-LepRb-KO) to evaluate its impact in lean metabolically normal mice in a murine model of pneumococcal pneumonia.
<b>Results:</b> We showed that serum miR-27a level correlated positively with obesity and insulin resistance in obese children, and that elevated serum miR-27a levels correlated with insulin resistance in leptin receptor-deficient db/db mice, and with obesity and insulin resistance in high-fat diet-fed C57BL/6J mice.
<b>Methods:</b> Initially to investigate the effect of obesity and IR in the analyzed parameters, insulin-sensitive eutrophic volunteers (CON; <i>n</i> = 9) and obese non-insulin (OB; <i>n</i> = 9) and insulin-resistant (OBR; <i>n</i> = 8) were enrolled.