scholarly journals Berberine-Improved Visceral White Adipose Tissue Insulin Resistance Associated with Altered Sterol Regulatory Element-Binding Proteins, Liver X Receptors, and Peroxisome Proliferator-Activated Receptors Transcriptional Programs in Diabetic Hamsters

2011 ◽  
Vol 34 (5) ◽  
pp. 644-654 ◽  
Author(s):  
Guo-Sheng Li ◽  
Xu-Han Liu ◽  
Hua Zhu ◽  
Lan Huang ◽  
Ya-Li Liu ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Binding Proteins ◽  
Regulatory Element ◽  
Peroxisome Proliferator ◽  
Liver X Receptors ◽  
Sterol Regulatory Element ◽  
Peroxisome Proliferator Activated Receptors ◽  
X Receptors

scholarly journals Lysosome-Dependent LXR and PPARδ Activation Upon Efferocytosis in Human Macrophages

2021 ◽  
Vol 12 ◽  
Author(s):  
Ana Carolina Mota ◽  
Monica Dominguez ◽  
Andreas Weigert ◽  
Ryan G. Snodgrass ◽  
Dmitry Namgaladze ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Target Genes ◽  
Inflammatory Responses ◽  
Regulatory Element ◽  
Peroxisome Proliferator ◽  
Liver X Receptors ◽  
Human Macrophages ◽  
Sterol Regulatory Element ◽  
Peroxisome Proliferator Activated Receptors ◽  
X Receptors

Efferocytosis is critical for tissue homeostasis, as its deregulation is associated with several autoimmune pathologies. While engulfing apoptotic cells, phagocytes activate transcription factors, such as peroxisome proliferator-activated receptors (PPAR) or liver X receptors (LXR) that orchestrate metabolic, phagocytic, and inflammatory responses towards the ingested material. Coordination of these transcription factors in efferocytotic human macrophages is not fully understood. In this study, we evaluated the transcriptional profile of macrophages following the uptake of apoptotic Jurkat T cells using RNA-seq analysis. Results indicated upregulation of PPAR and LXR pathways but downregulation of sterol regulatory element-binding proteins (SREBP) target genes. Pharmacological inhibition and RNA interference pointed to LXR and PPARδ as relevant transcriptional regulators, while PPARγ did not substantially contribute to gene regulation. Mechanistically, lysosomal digestion and lysosomal acid lipase (LIPA) were required for PPAR and LXR activation, while PPARδ activation also demanded an active lysosomal phospholipase A2 (PLA2G15). Pharmacological interference with LXR signaling attenuated ABCA1-dependent cholesterol efflux from efferocytotic macrophages, but suppression of inflammatory responses following efferocytosis occurred independently of LXR and PPARδ. These data provide mechanistic details on LXR and PPARδ activation in efferocytotic human macrophages.

scholarly journals PPARs and Metabolic Disorders Associated with Challenged Adipose Tissue Plasticity

2018 ◽  
Vol 19 (7) ◽  
pp. 2124 ◽  
Author(s):  
Patricia Corrales ◽  
Antonio Vidal-Puig ◽  
Gema Medina-Gómez
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Transcriptional Control ◽  
Hormone Receptors ◽  
Therapeutic Potential ◽  
Metabolic Stress ◽  
Regulatory Elements ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptors ◽  
X Receptors

Peroxisome proliferator-activated receptors (PPARs) are members of a family of nuclear hormone receptors that exert their transcriptional control on genes harboring PPAR-responsive regulatory elements (PPRE) in partnership with retinoid X receptors (RXR). The activation of PPARs coordinated by specific coactivators/repressors regulate networks of genes controlling diverse homeostatic processes involving inflammation, adipogenesis, lipid metabolism, glucose homeostasis, and insulin resistance. Defects in PPARs have been linked to lipodystrophy, obesity, and insulin resistance as a result of the impairment of adipose tissue expandability and functionality. PPARs can act as lipid sensors, and when optimally activated, can rewire many of the metabolic pathways typically disrupted in obesity leading to an improvement of metabolic homeostasis. PPARs also contribute to the homeostasis of adipose tissue under challenging physiological circumstances, such as pregnancy and aging. Given their potential pathogenic role and their therapeutic potential, the benefits of PPARs activation should not only be considered relevant in the context of energy balance-associated pathologies and insulin resistance but also as potential relevant targets in the context of diabetic pregnancy and changes in body composition and metabolic stress associated with aging. Here, we review the rationale for the optimization of PPAR activation under these conditions.

scholarly journals Central Leptin Regulates Total Ceramide Content and Sterol Regulatory Element Binding Protein-1C Proteolytic Maturation in Rat White Adipose Tissue

Endocrinology ◽  
2008 ◽  
Vol 150 (1) ◽  
pp. 169-178 ◽  
Author(s):  
Elena Bonzón-Kulichenko ◽  
Dominik Schwudke ◽  
Nilda Gallardo ◽  
Eduardo Moltó ◽  
Teresa Fernández-Agulló ◽  
...  
Keyword(s):  
Nervous System ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
White Adipose Tissue ◽  
Binding Protein ◽  
Regulatory Element ◽  
Mrna Levels ◽  
Element Binding Protein ◽  
Ceramide Content ◽  
Sterol Regulatory Element

Obesity and type 2 diabetes are associated with insulin and leptin resistance, and increased ceramide contents in target tissues. Because the adipose tissue has become a central focus in these diseases, and leptin-induced increases in insulin sensitivity may be related to effects of leptin on lipid metabolism, we investigated herein whether central leptin was able to regulate total ceramide levels and the expression of enzymes involved in ceramide metabolism in rat white adipose tissue (WAT). After 7 d central leptin treatment, the total content of ceramides was analyzed by quantitative shotgun lipidomics mass spectrometry. The effects of leptin on the expression of several enzymes of the sphingolipid metabolism, sterol regulatory element binding protein (SREBP)-1c, and insulin-induced gene 1 (INSIG-1) in this tissue were studied. Total ceramide levels were also determined after surgical WAT denervation. Central leptin infusion significantly decreased both total ceramide content and the long-chain fatty acid ceramide species in WAT. Concomitant with these results, leptin decreased the mRNA levels of enzymes involved in de novo ceramide synthesis (SPT-1, LASS2, LASS4) and ceramide production from sphingomyelin (SMPD-1/2). The mRNA levels of enzymes of ceramide degradation (Asah1/2) and utilization (sphingomyelin synthase, ceramide kinase, glycosyl-ceramide synthase, GM3 synthase) were also down-regulated. Ceramide-lowering effects of central leptin were prevented by local autonomic nervous system denervation of WAT. Finally, central leptin treatment markedly increased INSIG-1 mRNA expression and impaired SREBP-1c activation in epididymal WAT. These observations indicate that in vivo central leptin, acting through the autonomic nervous system, regulates total ceramide levels and SREBP-1c proteolytic maturation in WAT, probably contributing to improve the overall insulin sensitivity. Central leptin decreases total ceramide levels and prevents sterol regulatory element binding protein (SREBP-1C) proteolytic maturation in white adipose tissue, and probably, in this way, contributes to improve the overall insulin sensitivity.

scholarly journals Tissue-Specific Effects of Central Leptin on the Expression of Genes Involved in Lipid Metabolism in Liver and White Adipose Tissue

Endocrinology ◽  
2007 ◽  
Vol 148 (12) ◽  
pp. 5604-5610 ◽  
Author(s):  
Nilda Gallardo ◽  
Elena Bonzón-Kulichenko ◽  
Teresa Fernández-Agulló ◽  
Eduardo Moltó ◽  
Sergio Gómez-Alonso ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lipid Metabolism ◽  
White Adipose Tissue ◽  
Binding Protein ◽  
Regulatory Element ◽  
Epididymal Adipose Tissue ◽  
Key Enzymes ◽  
Specific Effects ◽  
Element Binding Protein ◽  
Sterol Regulatory Element

Leptin reduces adiposity and exerts antisteatotic effects on nonadipose tissues. However, the mechanisms underlying leptin effects on lipid metabolism in liver and white adipose tissue have not been fully clarified. Here, we have studied the effects of central leptin administration on key enzymes and transcription factors involved in lipid metabolism in liver and epididymal adipose tissue. Intracerebroventricular leptin infusion for 7 d did not change leptin plasma levels but decreased triacylglyceride content in liver, epididymal adipose tissue, and plasma. In both tissues this treatment markedly decreased the expression of key enzymes of the de novo fatty acid (FA) synthesis such as acetyl-coenzyme A-carboxylase, FA synthase, and stearoyl-coenzyme A desaturase-1, in parallel with a reduction in mRNA expression of sterol regulatory element binding protein-1c in liver and carbohydrate regulatory element binding protein in adipose tissue. In addition, leptin also decreased phosphoenol-pyruvate carboxykinase-C expression in adipose tissue, an enzyme involved in glyceroneogenesis in this tissue. Central leptin administration down-regulates delta-6-desaturase expression in liver and adipose tissue, in parallel with the decrease of the expression of sterol regulatory element binding protein-1c in liver and peroxisome proliferator activated receptor α in adipose tissue. Finally, leptin treatment, by regulating adipose triglyceride lipase/hormone sensitive lipase/diacylglycerol transferase 1 expression, also established a new partitioning in the FA-triacylglyceride cycling in adipose tissue, increasing lipolysis and probably the FA efflux from this tissue, and favoring in parallel the FA uptake and oxidation in the liver. These results suggest that leptin, acting at central level, exerts tissue-specific effects in limiting fat tissue mass and lipid accumulation in nonadipose tissues, preventing the development of obesity and type 2 diabetes.

Sign in / Sign up

Export Citation Format

Share Document