scholarly journals Role of Peroxisome Proliferator-Activated Receptor-γin Vascular Inflammation

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Kousei Ohshima ◽  
Masaki Mogi ◽  
Masatsugu Horiuchi

Vascular inflammation plays a crucial role in atherosclerosis, and its regulation is important to prevent cerebrovascular and coronary artery disease. The inflammatory process in atherogenesis involves a variety of immune cells including monocytes/macrophages, lymphocytes, dendritic cells, and neutrophils, which all express peroxisome proliferator-activated receptor-γ(PPAR-γ). PPAR-γis a nuclear receptor and transcription factor in the steroid superfamily and is known to be a key regulator of adipocyte differentiation. Increasing evidence from mainly experimental studies has demonstrated that PPAR-γactivation by endogenous and synthetic ligands is involved in lipid metabolism and anti-inflammatory activity. In addition, recent clinical studies have shown a beneficial effect of thiazolidinediones, synthetic PPAR-γligands, on cardiovascular disease beyond glycemic control. These results suggest that PPAR-γactivation is an important regulator in vascular inflammation and is expected to be a therapeutic target in the treatment of atherosclerotic complications. This paper reviews the recent findings of PPAR-γinvolvement in vascular inflammation and the therapeutic potential of regulating the immune system in atherosclerosis.

Endocrinology ◽  
2013 ◽  
Vol 154 (10) ◽  
pp. 3525-3538 ◽  
Author(s):  
Hong Guo ◽  
Merlijn Bazuine ◽  
Daozhong Jin ◽  
Merry M. Huang ◽  
Samuel W. Cushman ◽  
...  

Lipocalin 2 (Lcn2) has previously been characterized as an adipokine/cytokine playing a role in glucose and lipid homeostasis. In this study, we investigate the role of Lcn2 in adipose tissue remodeling during high-fat diet (HFD)-induced obesity. We find that Lcn2 protein is highly abundant selectively in inguinal adipose tissue. During 16 weeks of HFD feeding, the inguinal fat depot expanded continuously, whereas the expansion of the epididymal fat depot was reduced in both wild-type (WT) and Lcn2−/− mice. Interestingly, the depot-specific effect of HFD on fat mass was exacerbated and appeared more pronounced and faster in Lcn2−/− mice than in WT mice. In Lcn2−/− mice, adipocyte hypertrophy in both inguinal and epididymal adipose tissue was more profoundly induced by age and HFD when compared with WT mice. The expression of peroxisome proliferator-activated receptor-γ protein was significantly down-regulated, whereas the gene expression of extracellular matrix proteins was up-regulated selectively in epididymal adipocytes of Lcn2−/− mice. Consistent with these observations, collagen deposition was selectively higher in the epididymal, but not in the inguinal adipose depot of Lcn2−/− mice. Administration of the peroxisome proliferator-activated receptor-γ agonist rosiglitazone (Rosi) restored adipogenic gene expression. However, Lcn2 deficiency did not alter the responsiveness of adipose tissue to Rosi effects on the extracellular matrix expression. Rosi treatment led to the further enlargement of adipocytes with improved metabolic activity in Lcn2−/− mice, which may be associated with a more pronounced effect of Rosi treatment in reducing TGF-β in Lcn2−/− adipose tissue. Consistent with these in vivo observations, Lcn2 deficiency reduces the adipocyte differentiation capacity of stromal-vascular cells isolated from HFD-fed mice in these cells. Herein Rosi treatment was again able to stimulate adipocyte differentiation to a similar extent in WT and Lcn2−/− inguinal and epididymal stromal-vascular cells. Thus, combined, our data indicate that Lcn2 has a depot-specific role in HFD-induced adipose tissue remodeling.


Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2950 ◽  
Author(s):  
Quancai Sun ◽  
Jie Lin ◽  
Yukui Peng ◽  
Ruichang Gao ◽  
Ye Peng

Flubendiamide, a ryanoid class insecticide, is widely used in agriculture. Several insecticides have been reported to promote adipogenesis. However, the potential influence of flubendiamide on adipogenesis is largely unknown. The current study was therefore to determine the effects of flubendiamide on adipogenesis utilizing the 3T3-L1 adipocytes model. Flubendiamide treatment not only enhanced triglyceride content in 3T3-L1 adipocytes, but also increased the expression of cytosine-cytosine-adenosine-adenosine-thymidine (CCAAT)/enhancer-binding protein α and peroxisome proliferator-activated receptor gamma-γ, two important regulators of adipocyte differentiation. Moreover, the expression of the most important regulator of lipogenesis, acetyl coenzyme A carboxylase, was also increased after flubendiamide treatment. Further study revealed that 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) or A769662, two Adenosine 5′-monophosphate (AMP)-activated protein kinase α activators, subverted effects of flubendiamide on enhanced adipogenesis. Together, these results suggest that flubendiamide promotes adipogenesis via an AMPKα-mediated pathway.


PPAR Research ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Seong-Hoon Yun ◽  
Sang-Heum Han ◽  
Joo-In Park

Peroxisome proliferator-activated receptor γ (PPARγ) is part of a nuclear receptor superfamily that regulates gene expression involved in cell differentiation, proliferation, immune/inflammation response, and lipid metabolism. PPARγ coactivator-1α (PGC-1α), initially identified as a PPARγ-interacting protein, is an important regulator of diverse metabolic pathways, such as oxidative metabolism and energy homeostasis. The role of PGC-1α in diabetes, neurodegeneration, and cardiovascular disease is particularly well known. PGC-1α is also now known to play important roles in cancer, independent of the role of PPARγ in cancer. Though many researchers have studied the expression and clinical implications of PPARγ and PGC-1α in cancer, there are still many controversies about the role of PPARγ and PGC-1α in cancer. This review examines and summarizes some recent data on the role and action mechanisms of PPARγ and PGC-1α in cancer, respectively, particularly the recent progress in understanding the role of PPARγ in several cancers since our review was published in 2012.


Endocrinology ◽  
2010 ◽  
Vol 151 (11) ◽  
pp. 5247-5254 ◽  
Author(s):  
Victor Aguilar ◽  
Jean-Sébastien Annicotte ◽  
Xavier Escote ◽  
Joan Vendrell ◽  
Dominique Langin ◽  
...  

Cell cycle regulators such as cyclins, cyclin-dependent kinases, or retinoblastoma protein play important roles in the differentiation of adipocytes. In the present paper, we investigated the role of cyclin G2 as a positive regulator of adipogenesis. Cyclin G2 is an unconventional cyclin which expression is up-regulated during growth inhibition or apoptosis. Using the 3T3-F442A cell line, we observed an up-regulation of cyclin G2 expression at protein and mRNA levels throughout the process of cell differentiation, with a further induction of adipogenesis when the protein is transiently overexpressed. We show here that the positive regulatory effects of cyclin G2 in adipocyte differentiation are mediated by direct binding of cyclin G2 to peroxisome proliferator-activated receptor γ (PPARγ), the key regulator of adipocyte differentiation. The role of cyclin G2 as a novel PPARγ coactivator was further demonstrated by chromatin immunoprecipitation assays, which showed that the protein is present in the PPARγ-responsive element of the promoter of aP2, which is a PPARγ target gene. Luciferase reporter gene assays, showed that cyclin G2 positively regulates the transcriptional activity of PPARγ. The role of cyclin G2 in adipogenesis is further underscored by its increased expression in mice fed a high-fat diet. Taken together, our results demonstrate a novel role for cyclin G2 in the regulation of adipogenesis.


PPAR Research ◽  
2008 ◽  
Vol 2008 ◽  
pp. 1-12 ◽  
Author(s):  
Xiao Yi Yang ◽  
Li Hua Wang ◽  
William L. Farrar

Peroxisome proliferator-activated receptorγ(PPARγ) is a ligand-activated transcription factor and a member of the nuclear receptor superfamily. PPARγand its ligands appear to serve diverse biological functions. In addition to the well-studied effects of PPARγon metabolism and cellular differentiation, abundant evidence suggests that PPARγis an important regulator of the immune system and cancers. Since cytokines are not only key modulators of inflammation with pro- and anti-inflammatory functions but they also can either stimulate or inhibit tumor growth and progression, this review summarizes the role for PPARγin the regulation of cytokine production and cytokine-mediated signal transduction pathways in immune cells and cancer.


2000 ◽  
Vol 3 (2) ◽  
pp. 75-82 ◽  
Author(s):  
HANG SHI ◽  
YUAN-DI HALVORSEN ◽  
PAMELA N. ELLIS ◽  
WILLIAM O. WILKISON ◽  
MICHAEL B. ZEMEL

Shi, Hang, Yuan-Di Halvorsen, Pamela N. Ellis, William O. Wilkison, and Michael B. Zemel. Role of intracellular calcium in human adipocyte differentiation. Physiol Genomics 3: 75–82, 2000.—Intracellular calcium ([Ca2+]i) modulates adipocyte lipid metabolism and inhibits the early stages of murine adipogenesis. Consequently, we evaluated effects of increasing [Ca2+]i in early and late stages of human adipocyte differentiation. Increasing [Ca2+]i with either thapsigargin or A23187 at 0–1 h of differentiation markedly suppressed differentiation, with a 40–70% decrease in triglyceride accumulation and glycerol-3 phosphate dehydrogenase (GPDH) activity ( P < 0.005). However, a 1-h pulse of either agent at 47–48 h only modestly inhibited differentiation. Sustained, mild stimulation of Ca2+ influx with either agouti protein or 10 mM KCl-induced depolarization during 0–48 h of differentiation inhibited triglyceride accumulation and GPDH activity by 20–70% ( P < 0.05) and markedly suppressed peroxisome proliferator-activated receptor gamma (PPARγ) expression. These effects were reversed by Ca2+ channel antagonism. In contrast, Ca2+ pulses late in differentiation (71–72 h or 48–72 h) markedly increased these markers of differentiation. Thus increasing [Ca2+]i appears to exert a biphasic regulatory role in human adipocyte differentiation, inhibiting the early stages while promoting the late stage of differentiation and lipid filling.


2009 ◽  
Vol 30 (3) ◽  
pp. 613-625 ◽  
Author(s):  
Toshio Maekawa ◽  
Wanzhu Jin ◽  
Shunsuke Ishii

ABSTRACT ATF-2 is a member of the ATF/CREB family of transcription factors and is activated by stress-activated protein kinases, such as p38. To analyze the physiological role of ATF-2 family transcription factors, we have generated mice with mutations in Atf-2 and Cre-bpa, an Atf-2-related gene. The trans-heterozygotes of both mutants were lean and had reduced white adipose tissue (WAT). ATF-2 and CRE-BPa were required for bone morphogenetic protein 2 (BMP-2)-and p38-dependent induction of peroxisome proliferator-activated receptor γ2 (PPARγ2), a key transcription factor mediating adipocyte differentiation. Since stored fat supplies have been recognized as a possible target for antiobesity treatments, we tested whether inhibition of the p38-ATF-2 pathway suppresses adipocyte differentiation and leads to reduced WAT by treating mice with a p38 inhibitor for long periods of time. High-fat diet (HFD)-induced obesity was significantly reduced in mice fed the p38 inhibitor. Furthermore, the p38 inhibitor alleviated HFD-induced insulin resistance. In p38 inhibitor-treated mice, macrophage infiltration into WAT was reduced and the tumor necrosis factor alpha (TNF-α) levels were lower than control mice. Thus, p38 inhibitors may provide a novel antiobesity treatment.


2003 ◽  
Vol 127 (9) ◽  
pp. 1121-1123
Author(s):  
Arthur W. Bull

Abstract Objective.—Review the role and therapeutic potential of peroxisome proliferator–activated receptor (PPAR) γ in colonic disorders. Data Sources.—Recent peer-reviewed scientific literature focusing on PPAR γ in the colon. Study Selection.—Research reports using animal models, cultured cell lines, and clinical material were examined for content related to the role of PPAR γ in normal colon cell function, colon cancer, and inflammatory bowel disease. Issues concerned with potential therapeutic use were also considered. Data Synthesis.—Key points pertaining to PPAR function and involvement in colon pathology were extracted and noted. Potential compromises to therapeutic utility are identified. Conclusions.—The emerging important role of PPAR γ in normal tissue homeostasis and pathologic outcomes suggests this receptor is a good candidate as a drug target. Several potential problems with this approach will require further investigation prior to widespread recommendations for modulation of PPAR as an efficacious therapy for cancer, chemoprevention of colon cancer, or treatment of inflammatory bowel disease. The widespread use of PPAR γ ligands for management of type 2 diabetes (such as the glitazone class of drugs including rosiglitazone and pioglitazone) may provide a fortuitous assessment of the efficacy of long-term PPAR modulation.


PPAR Research ◽  
2008 ◽  
Vol 2008 ◽  
pp. 1-18 ◽  
Author(s):  
Tatiana M. Garcia-Bates ◽  
Geniece M. Lehmann ◽  
Patricia J. Simpson-Haidaris ◽  
Steven H. Bernstein ◽  
Patricia J. Sime ◽  
...  

Peroxisome proliferator-activated receptor gamma (PPARγ) is a multifunctional transcription factor with important regulatory roles in inflammation, cellular growth, differentiation, and apoptosis. PPARγis expressed in a variety of immune cells as well as in numerous leukemias and lymphomas. Here, we review recent studies that provide new insights into the mechanisms by which PPARγligands influence hematological malignant cell growth, differentiation, and survival. Understanding the diverse properties of PPARγligands is crucial for the development of new therapeutic approaches for hematological malignancies.


2004 ◽  
Vol 5 (2) ◽  
pp. 99-109 ◽  
Author(s):  
Todd Leff ◽  
Suresh T. Mathews ◽  
Heidi S. Camp

Since its identification as the receptor for antidiabetic thiazolidinedione drugs, peroxisome proliferator-activated receptor-γ(PPARγ) has been the focus of pharmaceutical drug discovery programs directed toward finding better drugs for the treatment of diabetes, as well as the object of basic research aimed at understanding its role in the regulation of metabolism. We now understand a great deal about the crucial role that PPARγplays in adipocyte differentiation and development, and are rapidly gaining knowledge about the role of the receptor in the regulation of metabolism. However, many crucial aspects of the molecular mechanism by which modulation of PPARγactivity affects insulin resistance and glucose homeostasis are still not clearly understood. Here the authors review the current status of PPARγresearch, with an emphasis on its role in the causes and treatment of type 2 diabetes.


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