ABSTRACT
Objective: The role of epigenetic modifications on leptin expression during the development of obesity has not been clearly determined. This study aimed to investigatechanges in the expression of DNA methyltransferases (DNMTs) at the leptin promoter and their effect on genetranscription during the development of obesity. Methods: Using a high-fat diet (HFD)-induced obese (DIO) mouse model, we examined adipose expression of leptin, its promoter associated DNMTs and the methyl CpG-binding domain protein 2 (MBD2) at different time points after HFD feeding. Results: The leptin expression levels in epididymal fat were significantly increased after feeding the mice aHFD for 4, 8, 12 and 18 weeks (w), as opposed to feeding them a standard diet (SD). However, the CpG promoter methylation fractions were significantly reduced at 8 w with a decreased association of MBD2 and DNMT1, and increased at 12 w and 18 w with an increased association of MBD2, DNMT3A and DNMT3B, after HFD feeding. Additionally, the binding of RNA polymerase II was increased at 8 w and decreased at 18 w after HFD feeding compared with SD feeding. Conclusions: These data indicate that time-specific changes in promoter associated DNMTs may be associated with the regulation of leptin expression, indicating that a complex and dynamic epigenetic mechanism underlies aberrant leptin expression during the development of obesity (AU)
Objetivo: El objetivo de las modificaciones epigenéticas sobre la expresión de la leptina durante el desarrollo de obesidad no ha podido ser claramente establecido. Este estudio tiene por objetivo investigar los cambios en la expresión de ADN-metiltransferasas (ADNMTs) en el promotor de leptina y su efecto sobre la trascripción génica durante el desarrollo de obesidad. Métodos: Empleando un modelo de ratones con obesidad inducida por dieta rica en grasa (DRG), examinamos la expresión adiposa de leptina, su promotor asociado ADNMTs y la proteína 2 con dominio de unión a metil-CpG (MBD2) en diferentes momentos tras la alimentación DRG. Resultados: Los niveles de expresión de leptina en grasa epididimal aumentaron significativamente tras la alimentación de los ratones con una dieta DRG durante 4, 8, 12 y 18 semanas (s), contrariamente a la alimentación con dieta estándar (DE). Sin embargo, las fracciones de metilación del promotor CpG se redujeron significativamente en la s8 con una menor asociación de MBD2 y DNMT1, y aumentaron en la s12 y s18 con una mayor asociación de MBD2, DNMT3A y DNMT3B, tras la DRG. Además, la unión de ARN polimerasa II aumentó en la s8 y disminuyó en la s18 tras la DRG en comparación con la alimentación de DE. Conclusiones: Estos datos indican que los cambios en puntos temporales específicos en ADNMTs en relación con un promotor podrían estar relacionados con la regulación de la expresión de leptina, indicando que existe un mecanismo epigenético dinámico y complejo subyacente en la expresión de leptina aberrante durante el desarrollo de obesidad (AU)
Subject(s)
Animals , Mice , /administration & dosage , /pharmacology , Epididymal Secretory Proteins/administration & dosage , Leptin/administration & dosage , /chemical synthesis , Epididymal Secretory Proteins , LeptinABSTRACT
Dehidroepiandrosterona (DHEA) y su derivada sulfatada (DHEAS) son los esteroides más abundantes en el cuerpo humano, pero aún se deconoce su mecanismo de acción y sus implicancias fisiológicas. Se le ha atribuido múltiples efectos antienvejecimiento, antiinflamatorio y antiarteriosclerótico entre otros y en EEUU se vende al público como complemento energético y para aumento del libido, sin restricción de la FDA...
Subject(s)
Humans , Epididymal Secretory Proteins/administration & dosage , Dehydroepiandrosterone Sulfate/therapeutic useABSTRACT
OBJECTIVE: To evaluate the immunocontraceptive properties of recombinant DE, a sperm epididymal protein involved in fertilization, via an experimental study in rats as a critical step toward the development of a human immunocontraceptive. DESIGN: In vivo study in rats. SETTING: Animal care facility of an academic research center. ANIMAL(S): Seventy-four 90-day-old Wistar male and female rats distributed into three groups. INTERVENTION(S): Animals received five injections (intramuscular and subcutaneous) of recombinant DE (recDE), native DE (nDE), or MBP (maltose-binding protein). At various times, animals were anesthetized and bled. MAIN OUTCOME MEASURE(S): Anti-DE levels and tissue specificity of sera were evaluated by enzyme-linked immunosorbent assay (ELISA) and Western blot, respectively. Fertility was analyzed by natural mating. The testes and epididymides were analyzed by histology. RESULT(S): Recombinant DE raised an immune response with the same kinetics and higher anti-DE levels than that elicited by nDE. Sera against recDE recognized epitopes of DE that were different from those recognized by anti-nDE sera but specifically reacted with DE in epididymis and sperm without cross-reacting with other tissues tested. Male and female recDE-injected animals presented a statistically significant reduction in their fertility with no evidence of pathologic effects. CONCLUSION(S): Recombinant DE is able to both elicit a specific immune response and inhibit male and female fertility, supporting the use of this sperm epididymal protein for the development of an immunocontraceptive approach.
