RESUMEN
AIMS: Leptin irresponsiveness, which is often associated with obesity, can have significant impacts on the hypothalamic proteome of individuals, including those who are lean. While mounting evidence on leptin irresponsiveness has focused on obese individuals, understanding the early molecular and proteomic changes associated with deficient hypothalamic leptin signaling in lean individuals is essential for early intervention and prevention of metabolic disorders. Leptin receptor antagonists block the binding of leptin to its receptors, potentially reducing its effects and used in cases where excessive leptin activity might be harmful. MATERIALS AND METHODS: In this work, we blocked the central actions of leptin in lean male adult Wistar rat by chronically administering intracerebroventricularly the superactive leptin receptor antagonist (SLA) (D23L/L39A/D40A/F41A) and investigated its impact on the hypothalamic proteome using label-free sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS) for quantitative proteomics. KEY FINDINGS: Our results show an accumulation of proteins involved in mRNA processing, mRNA stability, and translation in the hypothalamus of SLA-treated rats. Conversely, hypothalamic leptin signaling deficiency reduces the representation of proteins implicated in energy metabolism, neural circuitry, and neurotransmitter release. SIGNIFICANCE: The alterations in the adult rat hypothalamic proteome contribute to dysregulate appetite, metabolism, and energy balance, which are key factors in the development and progression of obesity and related metabolic disorders. Additionally, using bioinformatic analysis, we identified a series of transcription factors that are potentially involved in the upstream regulatory mechanisms responsible for the observed signature.
Asunto(s)
Hipotálamo , Leptina , Proteoma , Proteómica , Ratas Wistar , Receptores de Leptina , Transducción de Señal , Animales , Masculino , Leptina/metabolismo , Receptores de Leptina/metabolismo , Receptores de Leptina/genética , Receptores de Leptina/deficiencia , Hipotálamo/metabolismo , Hipotálamo/efectos de los fármacos , Ratas , Transducción de Señal/efectos de los fármacos , Proteómica/métodos , Proteoma/metabolismo , Obesidad/metabolismo , Metabolismo Energético/efectos de los fármacosRESUMEN
PURPOSE: Diabetic cardiomyopathy is a prevalent cardiovascular complication of diabetes mellitus. This study aimed to investigate the effects of ginsenoside Rb1 (GRb1) on the diabetic myocardium. METHODS: Leptin receptor-deficient db/db mice and palmitic acid (PA)-treated cardiomyocyte models were utilized. Cardiac systolic and diastolic function, mitochondrial morphology, and respiratory chain function were determined. The expression of mitochondrial dynamics proteins was measured. Mitofusin 2 (Mfn2) overexpression and inhibition were achieved by lentiviral infection and small interfering RNA (siRNA) transfection. RESULTS: In comparison to non-diabetic mice, db/db mice exhibited significant increases in body weight, blood glucose, blood lipids, and cardiac free fatty acid levels. This was accompanied by myocardial hypertrophy and left ventricular diastolic dysfunction, which were significantly ameliorated by GRb1 intervention. Stimulation with PA increased oxidative stress and apoptosis, and decreased viability in H9c2 cardiomyocytes. PA also reduced sarcomere contractility and relaxation in adult mice ventricular myocytes. PA-induced cellular and mitochondrial damage were reversed with GRb1 treatment. The cardiac tissue of db/db mice and PA-treated cardiomyocytes exhibited a decrease in Mfn2 expression, which was markedly improved by GRb1. Mfn2 overexpression reversed PA-induced mitochondrial fragmentation and functional damage in cardiomyocytes, while inhibition of Mfn2 expression by siRNA transfection blocked the protective effects of GRb1. CONCLUSION: GRb1 alleviated myocardial lipid accumulation and mitochondrial injury, and attenuated ventricular diastolic dysfunction in diabetic mice. The regulation of Mfn2 was involved in the protective effects of GRb1 against lipotoxic myocardial injury.
Asunto(s)
Cardiomiopatías Diabéticas , GTP Fosfohidrolasas , Ginsenósidos , Miocitos Cardíacos , Animales , Ginsenósidos/farmacología , Ginsenósidos/uso terapéutico , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Cardiomiopatías Diabéticas/metabolismo , Cardiomiopatías Diabéticas/tratamiento farmacológico , Cardiomiopatías Diabéticas/patología , Ratones , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Masculino , Ácido Palmítico/farmacología , Apoptosis/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/metabolismo , Ratas , Receptores de Leptina/genética , Receptores de Leptina/metabolismo , Receptores de Leptina/deficiencia , Línea Celular , Ratones Endogámicos C57BL , Miocardio/patología , Miocardio/metabolismoRESUMEN
Obesity is a chronic disease caused by excessive fat accumulation that impacts the body and brain health. Insufficient leptin or leptin receptor (LepR) is involved in the disease pathogenesis. Leptin is involved with several neurological processes, and it has crucial developmental roles. We have previously demonstrated that leptin deficiency in early life leads to permanent developmental problems in young adult mice, including an imbalance in energy homeostasis, alterations in melanocortin and the reproductive system and a reduction in brain mass. Given that in humans, obesity has been associated with brain atrophy and cognitive impairment, it is important to determine the long-term consequences of early-life leptin deficiency on brain structure and memory function. Here, we demonstrate that leptin-deficient (LepOb) mice exhibit altered brain volume, decreased neurogenesis and memory impairment. Similar effects were observed in animals that do not express the LepR (LepRNull). Interestingly, restoring the expression of LepR in 10-week-old mice reverses brain atrophy, in addition to neurogenesis and memory impairments in older animals. Our findings indicate that leptin deficiency impairs brain development and memory, which are reversible by restoring leptin signalling in adulthood.
Asunto(s)
Encéfalo , Leptina , Neurogénesis , Receptores de Leptina , Animales , Receptores de Leptina/deficiencia , Receptores de Leptina/genética , Receptores de Leptina/metabolismo , Ratones , Encéfalo/metabolismo , Leptina/deficiencia , Leptina/metabolismo , Neurogénesis/fisiología , Ratones Noqueados , Ratones Endogámicos C57BL , Masculino , Trastornos de la Memoria/metabolismo , Trastornos de la Memoria/genética , Atrofia/patologíaRESUMEN
The impaired bone healing in tooth extraction sockets due to periodontitis presents a major obstacle to restoring oral health. The mechanisms regulating the osteogenic capacity of jawbone-derived stromal cells in the periodontitis microenvironment remain elusive. Leptin receptor (LepR) expressing stromal cells, which largely overlap with Cxcl12-abundant reticular (CAR) cells in bone tissue, rapidly proliferate and differentiate into bone-forming cells during extraction socket healing to support alveolar bone repair. In this study, we identify that CCRL2 is significantly expressed and inhibits osteogenesis in LepR+/CAR cells of alveolar bones with periodontitis. The Ccrl2-KO mice exhibit significant improvements in bone healing in extraction sockets with periodontitis. Specifically, the binding of CCRL2 to SFRP1 on the surface of LepR+/CAR cells can amplify the suppressive effect of SFRP1 on Wnt signaling under inflammation, thus hindering the osteogenic differentiation of LepR+/CAR cells and resulting in poor bone healing in extraction sockets with periodontitis. Together, we clarify that the CCRL2 receptor of LepR+/CAR cells can respond to periodontitis and crosstalk with Wnt signaling to deteriorate extraction socket healing.
The impaired bone healing in tooth extraction sockets due to periodontitis presents a major obstacle to restoring oral health. Alterations in the cellular activity of LepR+/CAR cells, an essential stromal cell population for extraction socket healing, in the periodontitis microenvironment have yet to be determined. In this study, we identify that CCRL2, as a potent agent of inflammation-bone crosstalk, is significantly expressed and inhibits osteogenesis in LepR+/CAR cells of alveolar bones with periodontitis. Specifically, the binding of CCRL2 to SFRP1 on the surface of LepR+/CAR cells can amplify the suppressive effect of SFRP1 on the Wnt/ß-catenin signaling under inflammation, thus hindering the osteogenic differentiation of LepR+/CAR cells and resulting in poor bone healing in tooth extraction sockets with periodontitis.
Asunto(s)
Osteogénesis , Periodontitis , Receptores de Leptina , Vía de Señalización Wnt , Animales , Periodontitis/metabolismo , Periodontitis/patología , Receptores de Leptina/metabolismo , Receptores de Leptina/deficiencia , Receptores de Leptina/genética , Ratones , Ratones Noqueados , Células del Estroma/metabolismo , Células del Estroma/patología , Masculino , Humanos , Proceso Alveolar/patología , Proceso Alveolar/metabolismo , Cicatrización de Heridas , Proteínas de la Membrana/metabolismoRESUMEN
ABSTRACT: Prepubertal obesity is growing at an alarming rate and is now considered a risk factor for renal injury. Recently, we reported that the early development of renal injury in obese Dahl salt-sensitive (SS) leptin receptor mutant (SS LepR mutant) rats was associated with increased T-cell infiltration and activation before puberty. Therefore, the current study investigated the effect of inhibiting T-cell activation with abatacept on the progression of renal injury in young obese SS LepR mutant rats before puberty. Four-week-old SS and SS LepR mutant rats were treated with IgG or abatacept (1 mg/kg; ip, every other day) for 4 weeks. Abatacept reduced the renal infiltration of T cells by almost 50% in SS LepR mutant rats. Treatment with abatacept decreased the renal expression of macrophage inflammatory protein-3 alpha while increasing IL-4 in SS LepR mutant rats without affecting SS rats. While not having an impact on blood glucose levels, abatacept reduced hyperinsulinemia and plasma triglycerides in SS LepR mutant rats without affecting SS rats. We did not observe any differences in the mean arterial pressure among the groups. Proteinuria was markedly higher in SS LepR mutant rats than in SS rats throughout the study, and treatment with abatacept decreased proteinuria by about 40% in SS LepR mutant rats without affecting SS rats. We observed significant increases in glomerular and tubular injury and renal fibrosis in SS LepR mutant rats versus SS rats, and chronic treatment with abatacept significantly reduced these renal abnormalities in SS LepR mutant rats. These data suggest that renal T-cell activation contributes to the early progression of renal injury associated with prepubertal obesity.
Asunto(s)
Abatacept , Riñón , Obesidad , Ratas Endogámicas Dahl , Receptores de Leptina , Linfocitos T , Animales , Abatacept/farmacología , Obesidad/tratamiento farmacológico , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunología , Linfocitos T/metabolismo , Riñón/patología , Riñón/efectos de los fármacos , Riñón/metabolismo , Receptores de Leptina/genética , Receptores de Leptina/metabolismo , Receptores de Leptina/deficiencia , Masculino , Ratas , Progresión de la Enfermedad , Modelos Animales de Enfermedad , Proteinuria/tratamiento farmacológico , Enfermedades Renales/patología , Enfermedades Renales/tratamiento farmacológico , Enfermedades Renales/metabolismo , Maduración Sexual/efectos de los fármacosRESUMEN
In early stage of diabetes, insulin secretion from pancreatic ß-cells is increased to deal with the elevated blood glucose. Previous studies have reported that islet-produced carbon monoxide (CO) is associated with increased glucose-stimulated insulin secretion from ß-cells. However, this compensatory mechanism by which CO may act to enhance ß-cell function remain unclear. In this study, we revealed that CO promoted intracellular calcium ([Ca2+]i) elevation and glucose-stimulated insulin secretion (GSIS) from pancreatic ß-cells in leptin receptor deficient db/db mice but not in C57 mice. The stimulatory effects of CO on ß-cell function in db/db mice was blocked by inhibition of Phospholipase C (PLC) signaling pathway. We further demonstrated that CO triggered [Ca2+]i transients and enhanced GSIS in C57 islets when ß-cells overexpressed with PLCγ1 and PLCδ1, but not PLCß1. On the other hand, reducing PLCγ1 and PLCδ1 expressions in db/db islets dramatically attenuated the stimulatory effects of CO on ß-cell function, whereas interfering PLCß1 expression had no effects on CO-induced ß-cell function enhancement. Our findings showing that CO elevated [Ca2+]i and enhanced GSIS by activating PLC signaling through PLCγ1 and PLCδ1 isoforms in db/db pancreatic ß-cells may suggest an important mechanism by which CO promotes ß-cell function to prevent hyperglycemia. Our study may also provide new insights into the therapy for type II diabetes and offer a potential target for therapeutic applications of CO.
Asunto(s)
Calcio/metabolismo , Monóxido de Carbono/farmacología , Diabetes Mellitus Experimental/tratamiento farmacológico , Hipoglucemiantes/farmacología , Células Secretoras de Insulina/efectos de los fármacos , Fosfolipasa C delta/genética , Fosfolipasa C gamma/genética , Animales , Línea Celular , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patología , Regulación de la Expresión Génica , Glucosa/metabolismo , Glucosa/farmacología , Insulina/biosíntesis , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fosfolipasa C beta/antagonistas & inhibidores , Fosfolipasa C beta/genética , Fosfolipasa C beta/metabolismo , Fosfolipasa C delta/antagonistas & inhibidores , Fosfolipasa C delta/metabolismo , Fosfolipasa C gamma/antagonistas & inhibidores , Fosfolipasa C gamma/metabolismo , Receptores de Leptina/deficiencia , Receptores de Leptina/genética , Transducción de SeñalRESUMEN
Sensitization to the adipokine leptin is a promising therapeutic strategy against obesity and its comorbidities and has been proposed to contribute to the lasting metabolic benefits of Roux-en-Y gastric bypass (RYGB) surgery. We formally tested this idea using Zucker fatty fa/fa rats as an established genetic model of obesity, glucose intolerance, and fatty liver due to leptin receptor deficiency. We show that the changes in body weight in these rats following RYGB largely overlaps with that of diet-induced obese Wistar rats with intact leptin receptors. Further, food intake and oral glucose tolerance were normalized in RYGB-treated Zucker fatty fa/fa rats to the levels of lean Zucker fatty fa/+ controls, in association with increased glucagon-like peptide 1 (GLP-1) and insulin release. In contrast, while fatty liver was also normalized in RYGB-treated Zucker fatty fa/fa rats, their circulating levels of the liver enzyme alanine aminotransferase (ALT) remained elevated at the level of obese Zucker fatty fa/fa controls. These findings suggest that the leptin system is not required for the normalization of energy and glucose homeostasis associated with RYGB, but that its potential contribution to the improvements in liver health postoperatively merits further investigation.
Asunto(s)
Glucemia/metabolismo , Metabolismo Energético/genética , Homeostasis/genética , Obesidad/genética , Receptores de Leptina/deficiencia , Animales , Modelos Animales de Enfermedad , Hígado Graso/genética , Derivación Gástrica , Péptido 1 Similar al Glucagón/metabolismo , Prueba de Tolerancia a la Glucosa , Insulina/metabolismo , Obesidad/cirugía , Periodo Posoperatorio , Ratas , Ratas Wistar , Ratas Zucker , Pérdida de Peso/genéticaRESUMEN
The role of leptin in the development of intestinal inflammation remains controversial, since proinflammatory and anti-inflammatory effects have been described. This study describes the effect of the absence of leptin signaling in intestinal inflammation. Experimental colitis was induced by intrarectal administration of trinitrobenzene sulfonic acid (TNBS) to lean and obese Zucker rats (n = 10). Effects on inflammation and mucosal barrier were studied. Bacterial translocation and LPS concentration were evaluated together with colonic permeability to 4-kDa FITC-dextran. Obese Zucker rats showed a lower intestinal myeloperoxidase and alkaline phosphatase activity, reduced alkaline phosphatase sensitivity to levamisole, and diminished colonic expression of Nos2, Tnf, and Il6, indicating attenuated intestinal inflammation, associated with attenuated STAT3, AKT, and ERK signaling in the colonic tissue. S100a8 and Cxcl1 mRNA levels were maintained, suggesting that in the absence of leptin signaling neutrophil activation rather than infiltration is hampered. Despite the lower inflammatory response, leptin resistance enhanced intestinal permeability, reflecting an increased epithelial damage. This was shown by augmented LPS presence in the portal vein of colitic obese Zucker rats, associated with induction of tissue nonspecific alkaline phosphatase, LPS-binding protein, and CD14 hepatic expression (involved in LPS handling). This was linked to decreased ZO-1 immunoreactivity in tight junctions and lower occludin expression. Our results indicate that obese Zucker rats present an attenuated inflammatory response to TNBS, but increased intestinal epithelial damage allowing the passage of bacterial antigens.NEW & NOTEWORTHY Obese Zucker rats, which are resistant to leptin, exhibit a diminished inflammatory response in the trinitrobenzenesulfonic acid (TNBS) model of colitis, suggesting leptin role is proinflammatory. At the same time, obese Zucker rats present a debilitated intestinal barrier function, with increased translocation of LPS. Zucker rats present a dual response in the TNBS model of rat colitis.
Asunto(s)
Colitis Ulcerosa/metabolismo , Mucosa Intestinal/metabolismo , Leptina/metabolismo , Lipopolisacáridos/farmacología , Fosfatasa Alcalina/metabolismo , Animales , Calgranulina A/metabolismo , Quimiocina CXCL1/metabolismo , Colitis Ulcerosa/etiología , Colitis Ulcerosa/patología , Interleucina-6/genética , Interleucina-6/metabolismo , Absorción Intestinal , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/patología , Sistema de Señalización de MAP Quinasas , Masculino , Óxido Nítrico Sintasa de Tipo II/metabolismo , Peroxidasa/metabolismo , Ratas , Ratas Zucker , Receptores de Leptina/deficiencia , Receptores de Leptina/genética , Factor de Transcripción STAT3/metabolismo , Proteínas de Uniones Estrechas/metabolismo , Ácido Trinitrobencenosulfónico/toxicidad , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
[Figure: see text].
Asunto(s)
Degranulación de la Célula , Vasos Coronarios/metabolismo , Diabetes Mellitus , Insuficiencia Cardíaca/etiología , Mastocitos/metabolismo , Obesidad/complicaciones , Disfunción Ventricular Izquierda/etiología , Función Ventricular Izquierda , Animales , Células Cultivadas , Vasos Coronarios/inmunología , Vasos Coronarios/patología , Diabetes Mellitus/genética , Diabetes Mellitus/inmunología , Diabetes Mellitus/metabolismo , Diástole , Modelos Animales de Enfermedad , Femenino , Insuficiencia Cardíaca/inmunología , Insuficiencia Cardíaca/metabolismo , Insuficiencia Cardíaca/fisiopatología , Liberación de Histamina , Humanos , Mastocitos/inmunología , Mastocitos/patología , Ratones Noqueados , Miocardio/inmunología , Miocardio/metabolismo , Miocardio/patología , Obesidad/inmunología , Obesidad/metabolismo , Receptores de Leptina/deficiencia , Receptores de Leptina/genética , Disfunción Ventricular Izquierda/inmunología , Disfunción Ventricular Izquierda/metabolismo , Disfunción Ventricular Izquierda/fisiopatologíaRESUMEN
[Figure: see text].
Asunto(s)
Anticolesterolemiantes , Glucemia , Colesterol , Diabetes Mellitus , Hiperlipidemias , Hipoglucemiantes , Hígado , Metformina , Proproteína Convertasa 9 , Adolescente , Adulto , Animales , Humanos , Masculino , Adulto Joven , Anticolesterolemiantes/uso terapéutico , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/genética , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/metabolismo , Biomarcadores/sangre , Glucemia/efectos de los fármacos , Glucemia/metabolismo , Colesterol/sangre , Diabetes Mellitus/sangre , Diabetes Mellitus/tratamiento farmacológico , Diabetes Mellitus/enzimología , Diabetes Mellitus/genética , Modelos Animales de Enfermedad , Regulación Enzimológica de la Expresión Génica , Células Hep G2 , Hiperlipidemias/sangre , Hiperlipidemias/tratamiento farmacológico , Hiperlipidemias/enzimología , Hiperlipidemias/genética , Hipoglucemiantes/uso terapéutico , Hígado/efectos de los fármacos , Hígado/enzimología , Metformina/uso terapéutico , Ratones Endogámicos C57BL , Ratones Noqueados , Proproteína Convertasa 9/genética , Proproteína Convertasa 9/metabolismo , Receptores de Leptina/deficiencia , Receptores de Leptina/genética , Resultado del TratamientoRESUMEN
Ethanol abuse is a common issue in individuals with sedentary lifestyles, unbalanced diets, and metabolic syndrome. Both ethanol abuse and metabolic syndrome have negative impacts on the central nervous system, with effects including cognitive impairment and brain oxidative status deterioration. The combined effects of ethanol abuse and metabolic syndrome at a central level have not yet been elucidated in detail. Thus, this work aims to determine the effects of ethanol intake on a mouse model of metabolic syndrome at the behavioral and biochemical levels. Seven-week-old male control (B6.V-Lep ob/+JRj) and leptin-deficient (metabolic syndrome) (B6.V-Lep ob/obJRj) mice were used in the study. Animals were divided into four groups: control, ethanol, obese, and obese-ethanol. Ethanol consumption was monitored for 6 weeks. Basal glycemia, insulin, and glucose overload tests were performed. To assess short- and long-term memory, an object recognition test was used. In order to assess oxidative status in mouse brain samples, antioxidant enzyme activity was analyzed with regard to glutathione peroxidase, glutathione reductase, glutathione, glutathione disulfide, lipid peroxidation products, and malondialdehyde. Ethanol intake modulated the insulin response and impaired the oxidative status in the ob mouse brain.
Asunto(s)
Modelos Animales de Enfermedad , Etanol/farmacología , Síndrome Metabólico/metabolismo , Receptores de Leptina/deficiencia , Animales , Antioxidantes/metabolismo , Glucemia/metabolismo , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Depresores del Sistema Nervioso Central/administración & dosificación , Depresores del Sistema Nervioso Central/farmacología , Etanol/administración & dosificación , Glutatión/metabolismo , Glutatión Peroxidasa/metabolismo , Glutatión Reductasa/metabolismo , Humanos , Insulina/sangre , Insulina/metabolismo , Masculino , Malondialdehído/metabolismo , Síndrome Metabólico/sangre , Síndrome Metabólico/genética , Ratones Endogámicos C57BL , Ratones Noqueados , Obesidad/sangre , Obesidad/genética , Obesidad/metabolismo , Receptores de Leptina/genéticaRESUMEN
BACKGROUND: The melanocortin 4 receptor (MC4R), a component of the leptin-melanocortin pathway, plays a part in bodyweight regulation. Severe early-onset obesity can be caused by biallelic variants in genes that affect the MC4R pathway. We report the results from trials of the MC4R agonist setmelanotide in individuals with severe obesity due to either pro-opiomelanocortin (POMC) deficiency obesity or leptin receptor (LEPR) deficiency obesity. METHODS: These single-arm, open-label, multicentre, phase 3 trials were done in ten hospitals across Canada, the USA, Belgium, France, Germany, the Netherlands, and the UK. Participants aged 6 years or older with POMC or LEPR deficiency obesity received open-label setmelanotide for 12 weeks. Participants with at least 5 kg weight loss (or ≥5% if weighing <100 kg at baseline) entered an 8-week placebo-controlled withdrawal sequence (including 4 weeks each of blinded setmelanotide and placebo treatment) followed by 32 additional weeks of open-label treatment. The primary endpoint, which was assessed in participants who received at least one dose of study medication and had a baseline assessment (full analysis set), was the proportion of participants with at least 10% weight loss compared with baseline at approximately 1 year. A key secondary endpoint was mean percentage change in the most hunger score of the 11-point Likert-type scale at approximately 1 year on the therapeutic dose, which was assessed in a subset of participants aged 12 years or older in the full analysis set who demonstrated at least 5 kg weight loss (or ≥5% in paediatric participants if baseline bodyweight was <100 kg) over the 12-week open-label treatment phase and subsequently proceeded into the placebo-controlled withdrawal sequence, regardless of later disposition. These studies are registered with ClinicalTrials.gov, NCT02896192 and NCT03287960. FINDINGS: Between Feb 14, 2017, and Sept 7, 2018, ten participants were enrolled in the POMC trial and 11 participants were enrolled in the LEPR trial, and included in the full analysis and safety sets. Eight (80%) participants in the POMC trial and five (45%) participants in the LEPR trial achieved at least 10% weight loss at approximately 1 year. The mean percentage change in the most hunger score was -27·1% (n=7; 90% CI -40·6 to -15·0; p=0·0005) in the POMC trial and -43·7% (n=7; -54·8 to -29·1; p<0·0001) in the LEPR trial. The most common adverse events were injection site reaction and hyperpigmentation, which were reported in all ten participants in the POMC trial; nausea was reported in five participants and vomiting in three participants. In the LEPR trial, the most commonly reported treatment-related adverse events were injection site reaction in all 11 participants, skin disorders in five participants, and nausea in four participants. No serious treatment-related adverse events occurred in both trials. INTERPRETATION: Our results support setmelanotide for the treatment of obesity and hyperphagia caused by POMC or LEPR deficiency. FUNDING: Rhythm Pharmaceuticals.
Asunto(s)
Insuficiencia Suprarrenal/complicaciones , Fármacos Antiobesidad/uso terapéutico , Obesidad/tratamiento farmacológico , Proopiomelanocortina/deficiencia , Receptor de Melanocortina Tipo 4/agonistas , Receptores de Leptina/deficiencia , alfa-MSH/análogos & derivados , Adolescente , Adulto , Niño , Método Doble Ciego , Femenino , Estudios de Seguimiento , Humanos , Masculino , Obesidad/complicaciones , Obesidad/etiología , Obesidad/patología , Pronóstico , Adulto Joven , alfa-MSH/uso terapéuticoRESUMEN
The mechanisms of highland barley whole grain (BWG) with rich phenolics on obese db/db mice were investigated in this study. Oral consumption of BWG reduced food intake, body weight, organ/body weight indexes of liver and fat, levels of serum and hepatic lipids, liver injury, and oxidative stress. Furthermore, BWG recovered the disorder of cecal microbiota by augmenting the Bacteroidetes/Firmicutes ratio and Alistipes abundance and decreasing the abundances of Bacteroides and Desulfovibrionaceae to modulate lipid metabolism-related genes. BWG inhibited fatty acid biosynthesis via upregulating the phosphorylation of AMP-activated protein kinase α, while downregulating sterol regulatory element binding protein-1c, fatty acid synthase (FAS), and stearoyl-CoA desaturase 1 levels. BWG also significantly downregulated miRNA-122, miRNA-33, miRNA-34a, and miRNA-206 levels. Accordingly, BWG exhibited hypolipidemic potential through modulating cecal microbiota, AMPK/SREBP-1c/FAS pathway, and related miRNAs, triggering the alleviation of dyslipidemia. These findings suggested BWG as an effective candidate to ameliorate the symptoms of hyperlipidemia.
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Proteínas Quinasas Activadas por AMP/metabolismo , Ciego/microbiología , Microbioma Gastrointestinal , Hordeum/metabolismo , Hiperlipidemias/dietoterapia , Receptores de Leptina/deficiencia , Proteínas Quinasas Activadas por AMP/genética , Animales , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Ciego/metabolismo , Modelos Animales de Enfermedad , Ácido Graso Sintasas/genética , Ácido Graso Sintasas/metabolismo , Humanos , Hiperlipidemias/genética , Hiperlipidemias/metabolismo , Hiperlipidemias/microbiología , Hígado/metabolismo , Masculino , Ratones , Ratones Noqueados , MicroARNs/genética , MicroARNs/metabolismo , Receptores de Leptina/genética , Semillas/metabolismo , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/genética , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismoRESUMEN
Leptin, secreted by peripheral adipocytes, binds the leptin receptor (Lepr) in the hypothalamus, thereby contributing to the regulation of satiety and body weight. Lepr is expressed in the embryonic brain as early as embryonic day 12.5. However, the function of Lepr in neural precursor cells in the brain has not been resolved. To address this issue, we crossed the Leprflox/flox mice with each of Shh-Cre mice (Shh, sonic hedgehog) and Nestin (Nes)-Cre mice. We found that deletion of Lepr specifically in nestin-expressing cells led to extreme obesity, but the conditional null of Lepr in Shh-expressing cells had no obvious phenotype. Moreover, the level of leptin-activated pSTAT3 decreased in the anterior and central subregions of the arcuate hypothalamus of Shh-Cre; Leprflox/flox mice compared with the controls. By contrast, in Nes-Cre; Leprflox/flox mice, the level of leptin-activated pSTAT3 decreased in all subregions including the anterior, central, and posterior arcuate hypothalamus as well as the dorsomedial, ventromedial, and median eminence of the hypothalamus, revealing that the extensive lack of Lepr in the differentiated neurons of the hypothalamus in the conditional null mice. Notably, conditional deletion of Lepr in nestin-expressing cells enhanced the differentiation of neural precursor cells into neurons and oligodendroglia but inhibited differentiation into astrocytes early in postnatal development of hypothalamus. Our results suggest that Lepr expression in neural precursor cells is essential for maintaining normal body weight as well as the differentiation of neural precursor cells to the neural/glial fate in the hypothalamus shortly after birth.
Asunto(s)
Diferenciación Celular , Hipotálamo/patología , Células-Madre Neurales/metabolismo , Neuronas/patología , Obesidad/metabolismo , Receptores de Leptina/deficiencia , Animales , Animales Recién Nacidos , Linaje de la Célula/efectos de los fármacos , Integrasas/metabolismo , Leptina/farmacología , Ratones Endogámicos C57BL , Ratones Noqueados , Nestina/metabolismo , Neuronas/metabolismo , Fenotipo , Fosforilación , Receptores de Leptina/metabolismo , Factor de Transcripción STAT3/metabolismoRESUMEN
Mitochondrial dysfunction plays a critical role in the pathogenesis of diabetic cardiomyopathy. Translocase of mitochondrial outer membrane 70 (Tom70) primarily facilitates the import of mitochondrial preproteins that may be involved in the regulation of oxidative stress and mitochondrial function. This study aimed to investigate the role of Tom70 in the development of myocardial injury in leptin receptor-deficient (db/db) diabetic mice. Tom70 siRNA or an overexpressing lentivirus was intramuscularly injected into mouse hearts or used to treat cultured neonatal cardiomyocytes. We found that Tom70 was downregulated in the diabetic hearts compared with the level in the wild-type hearts and that knocking down Tom70 exacerbated cardiac hypertrophy, fibrosis, and ventricular dysfunction in the db/db mice. Similarly, the in vitro data demonstrated that silencing Tom70 enhanced high-glucose and high-fat (HGHF) medium treatment-induced mitochondrial superoxide production, decreased ATP production and the mitochondrial membrane potential, and enhanced cell apoptosis in neonatal cardiomyocytes. Importantly, overexpression of Tom70 alleviated HGHF medium-induced oxidative stress, mitochondrial dysfunction, and cell apoptosis. Furthermore, in vivo data confirmed that reconstitution of Tom70 ameliorated cardiac hypertrophy, interstitial fibrosis, and ventricular dysfunction in the db/db mice. In addition, Tom70 overexpression mitigated mitochondrial fragmentation and dysfunction in the hearts of the db/db mice. Taken together, these findings suggest that downregulation of Tom70 contributes to the development of diabetic cardiomyopathy and that reconstitution of Tom70 may be a new therapeutic strategy for the prevention and treatment of diabetic cardiomyopathy.
Asunto(s)
Cardiomiopatías Diabéticas/etiología , Terapia Genética , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Animales , Animales Recién Nacidos , Apoptosis , Cardiomegalia/metabolismo , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Tipo 2/complicaciones , Cardiomiopatías Diabéticas/metabolismo , Cardiomiopatías Diabéticas/terapia , Regulación hacia Abajo , Lentivirus , Masculino , Ratones Endogámicos C57BL , Proteínas de Transporte de Membrana Mitocondrial/genética , Proteínas del Complejo de Importación de Proteínas Precursoras Mitocondriales , Miocitos Cardíacos/fisiología , Estrés Oxidativo , Cultivo Primario de Células , Receptores de Leptina/deficienciaRESUMEN
Type 2 diabetes and obesity are associated with back pain in juveniles and adults and are implicated in intervertebral disc (IVD) degeneration. Hypercaloric Western diets are associated with both obesity and type 2 diabetes. The objective of this study was to determine if obesity and type 2 diabetes result in spinal pathology in a sex-specific manner using in vivo diabetic and dietary mouse models. Leptin is an appetite-regulating hormone, and its deficiency leads to polyphagia, resulting in obesity and diabetes. Leptin is also associated with IVD degeneration, and increased expression of its receptor was identified in degenerated IVDs. We used young, leptin receptor deficient (Db/Db) mice to mimic the effect of diet and diabetes on adolescents. Db/Db and Control mice were fed either Western or Control diets, and were sacrificed at 3 months of age. Db/Db mice were obese, while only female mice developed diabetes. Female Db/Db mice displayed altered IVD morphology, with increased intradiscal notochordal band area, suggesting delayed IVD cell proliferation and differentiation, rather than IVD degeneration. Motion segments from Db/Db mice exhibited increased failure risk with decreased torsional failure strength. Db/Db mice also had inferior bone quality, which was most prominent in females. We conclude that obesity and diabetes due to impaired leptin signaling contribute to pathological changes in vertebrae, as well as an immature IVD phenotype, particularly of females, suggesting a sex-dependent role of leptin in the spine.
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Diabetes Mellitus Tipo 2/genética , Degeneración del Disco Intervertebral/genética , Leptina/genética , Obesidad/genética , Receptores de Leptina/genética , Animales , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patología , Dieta Occidental/efectos adversos , Modelos Animales de Enfermedad , Femenino , Humanos , Disco Intervertebral/metabolismo , Disco Intervertebral/patología , Degeneración del Disco Intervertebral/metabolismo , Degeneración del Disco Intervertebral/patología , Leptina/metabolismo , Masculino , Ratones , Ratones Endogámicos NOD , Obesidad/metabolismo , Obesidad/patología , Receptores de Leptina/deficiencia , Caracteres Sexuales , Transducción de Señal/genética , Columna Vertebral/metabolismo , Columna Vertebral/patologíaRESUMEN
The gut microbiome plays an important role in obesity and Type 2 diabetes (T2D); however, it remains unclear whether the gut microbiome could clarify the dietary versus genetic origin of these ailments. Moreover, studies examining the gut microbiome in diet- versus genetically induced obesity/T2D in the same experimental set-up are lacking. We herein characterized the gut microbiomes in three of the most widely used mouse models of obesity/T2D, i.e., genetically induced (leptin-deficient i.e., Lepob/ob; and leptin-receptor-deficient i.e., Lepdb/db) and high-fat diet (HFD)-induced obese (DIO)/T2D mice, with reference to their normal chow-fed (NC) and low-fat-diet-fed (LF) control counterparts. In terms of ß-diversity, Lepob/ob and Lepdb/db mice showed similarity to NC mice, whereas DIO and LF mice appeared as distinct clusters. The phylum- and genus-level compositions were relatively similar in NC, Lepob/ob, and Lepdb/db mice, whereas DIO and LF mice demonstrated distinct compositions. Further analyses revealed several unique bacterial taxa, metagenomic functional features, and their correlation patterns in these models. The data revealed that obesity/T2D driven by diet as opposed to genetics presents distinct gut microbiome signatures enriched with distinct functional capacities, and indicated that these signatures can distinguish diet- versus genetically induced obesity/T2D and, if extrapolated to humans, might offer translational potential in devising dietary and/or genetics-based therapies against these maladies.
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Diabetes Mellitus Tipo 2/microbiología , Microbioma Gastrointestinal/genética , Leptina/genética , Obesidad/microbiología , Receptores de Leptina/genética , Animales , Diabetes Mellitus Tipo 2/genética , Dieta Alta en Grasa/efectos adversos , Humanos , Leptina/deficiencia , Masculino , Ratones , Ratones Endogámicos NOD/genética , Obesidad/genética , Obesidad/patología , Receptores de Leptina/deficienciaRESUMEN
In the pregnant mouse, the hormone leptin is primarily produced by adipose tissue and does not significantly cross the placenta into fetal circulation. Nonetheless, leptin treatment during gestation affects offspring phenotypes. Leptin treatment also affects placental trophoblast cells in vitro, by altering proliferation, invasion and nutrient transport. The goal of the present study was to determine whether the absence of placental leptin receptors alters placental development and gene expression. Leprdb-3j+ mice possessing only one functional copy of the leptin receptor were mated to obtain wildtype, Leprdb-3j+ and Leprdb-3j/db-3j conceptuses, which were then transferred to wildtype recipient dams. Placentas were collected at gestational d18.5 to examine placental morphology and gene expression. Placentas lacking functional leptin receptor had reduced weights, but were otherwise morphologically indistinguishable from control placentas. Relative mRNA levels, however, were altered in Leprdb-3j/db-3j placentas, particularly transcripts related to amino acid and lipid metabolism and transport. Consistent with a previous in vitro study, leptin was found to promote expression of stathmin, a positive regulator of trophoblast invasion, and of serotonin receptors, potential mediators of offspring neurological development. Overall placental leptin receptor was found not to play a significant role in morphological development of the placenta, but to regulate placental gene expression, including in metabolic pathways that affect fetal growth.
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Regulación del Desarrollo de la Expresión Génica , Placenta/anatomía & histología , Placenta/metabolismo , Receptores de Leptina/deficiencia , Animales , Transferencia de Embrión , Femenino , Desarrollo Fetal , Perfilación de la Expresión Génica , Masculino , Ratones Endogámicos C57BL , EmbarazoRESUMEN
OBJECTIVE: Diabetes mellitus is a significant risk factor for peripheral artery disease. Diabetes mellitus induces chronic states of oxidative stress and vascular inflammation that increase neutrophil activation and release of myeloperoxidase. The goal of this study is to determine whether inhibiting myeloperoxidase reduces oxidative stress and neutrophil infiltration, increases vascularization, and improves blood flow in a diabetic murine model of hindlimb ischaemia. METHODS: Leptin receptor-deficient (db/db) mice were subjected to hindlimb ischaemia. Ischaemic mice were treated with N-acetyl-lysyltyrosylcysteine-amide (KYC) to inhibit myeloperoxidase. After ligating the femoral artery, effects of treatments were determined with respect to hindlimb blood flow, neutrophil infiltration, oxidative damage, and the capability of hindlimb extracellular matrix to support human endothelial cell proliferation and migration. RESULTS: KYC treatment improved hindlimb blood flow at 7 and 14 days in db/db mice; decreased the formation of advanced glycation end products, 4-hydroxynonenal, and 3-chlorotyrosine; reduced neutrophil infiltration into the hindlimbs; and improved the ability of hindlimb extracellular matrix from db/db mice to support endothelial cell proliferation and migration. CONCLUSION: These results demonstrate that inhibiting myeloperoxidase reduces oxidative stress in ischaemic hindlimbs of db/db mice, which improves blood flow and reduces neutrophil infiltration such that hindlimb extracellular matrix from db/db mice supports endothelial cell proliferation and migration.
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Inductores de la Angiogénesis/farmacología , Diabetes Mellitus/metabolismo , Inhibidores Enzimáticos/farmacología , Isquemia/tratamiento farmacológico , Músculo Esquelético/irrigación sanguínea , Neovascularización Fisiológica/efectos de los fármacos , Neutrófilos/efectos de los fármacos , Oligopéptidos/farmacología , Peroxidasa/antagonistas & inhibidores , Animales , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Diabetes Mellitus/genética , Diabetes Mellitus/fisiopatología , Modelos Animales de Enfermedad , Matriz Extracelular/metabolismo , Miembro Posterior , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Isquemia/enzimología , Isquemia/fisiopatología , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Infiltración Neutrófila/efectos de los fármacos , Neutrófilos/enzimología , Estrés Oxidativo/efectos de los fármacos , Peroxidasa/metabolismo , Receptores de Leptina/deficiencia , Receptores de Leptina/genética , Flujo Sanguíneo Regional , Transducción de SeñalRESUMEN
Angiotensin II (ANG II) Agtr1a receptor (AT1A) is expressed in cells of the arcuate nucleus of the hypothalamus that express the leptin receptor (Lepr) and agouti-related peptide (Agrp). Agtr1a expression in these cells is required to stimulate resting energy expenditure in response to leptin and high-fat diets (HFDs), but the mechanism activating AT1A signaling by leptin remains unclear. To probe the role of local paracrine/autocrine ANG II generation and signaling in this mechanism, we bred mice harboring a conditional allele for angiotensinogen (Agt, encoding AGT) with mice expressing Cre-recombinase via the Lepr or Agrp promoters to cause cell-specific deletions of Agt (AgtLepr-KO and AgtAgrp-KO mice, respectively). AgtLepr-KO mice were phenotypically normal, arguing against a paracrine/autocrine AGT signaling mechanism for metabolic control. In contrast, AgtAgrp-KO mice exhibited reduced preweaning survival, and surviving adults exhibited altered renal structure and steroid flux, paralleling previous reports of animals with whole body Agt deficiency or Agt disruption in albumin (Alb)-expressing cells (thought to cause liver-specific disruption). Surprisingly, adult AgtAgrp-KO mice exhibited normal circulating AGT protein and hepatic Agt mRNA expression but reduced Agt mRNA expression in adrenal glands. Reanalysis of RNA-sequencing data sets describing transcriptomes of normal adrenal glands suggests that Agrp and Alb are both expressed in this tissue, and fluorescent reporter gene expression confirms Cre activity in adrenal gland of both Agrp-Cre and Alb-Cre mice. These findings lead to the iconoclastic conclusion that extrahepatic (i.e., adrenal) expression of Agt is critically required for normal renal development and survival.