scholarly journals Enhanced Hepatocarcinogenicity Due to Agonists of Peroxisome Proliferator-Activated Receptors in Senescent Rats: Role of Peroxisome Proliferation, Cell Proliferation, and Apoptosis

2002 ◽  
Vol 2 ◽  
pp. 1491-1500 ◽  
Author(s):  
Jihan Youssef ◽  
Mostafa Badr
Keyword(s):  
Cell Proliferation ◽  
Peroxisome Proliferator ◽  
Carcinogenic Effect ◽  
Peroxisome Proliferator Activated Receptor ◽  
New Findings ◽  
Proliferation And Apoptosis ◽  
Ppar Agonists ◽  
Old Rats ◽  
Peroxisome Proliferator Activated Receptors

Exposure to agonists of peroxisome proliferator-activated receptor alpha (PPARα) causes liver cancer in rodents, with aged animals being more susceptible than their younger counterparts to this effect. Treatment with these chemicals produced a five- to sevenfold higher yield of grossly visible hepatic tumors in old rats compared to young animals. The enhanced susceptibility of the aged livers to the carcinogenic effect of PPAR agonists could not be explained by differences in levels of peroxisomal and/or cell proliferation between young and old animals, as neither of these responses was exaggerated with aging. Reported studies have shown that activating PPARa results in the suppression of hepatic apoptosis. This effect is expected to diminish the ability of the liver to purge itself of pre-existing neoplastic cells, allowing them to progress to tumors. New findings from our laboratories show that the aged liver is exceedingly sensitive to the antiapoptotic effect of PPAR agonists. In addition, aged livers showed remarkably higher levels of the antiapoptotic protein Bcl-2 than livers of young, adult, and middle-aged animals. Interestingly, the PPARa agonist Wy-14,643 significantly diminished elements of the proapoptotic machinery (e.g., Bax, caspases, and fas) in the aged liver, while remarkably increasing elements of this machinery in younger animals. Taken together, while activation of PPARs appears to inhibit apoptosis in livers of senescent animals, activating these receptors seems to stimulate the apoptotic machinery in young animals. This paradoxical effect may be responsible for the exaggerated sensitivity of the aged liver to the carcinogenic effect of agents that activate PPARs.

New trends in the pharmacological intervention of PPARs in obesity: Role of natural and synthetic compounds_

2020 ◽  
Vol 28 ◽  
Author(s):  
Seyed Mohammad Nabavi ◽  
Kasi Pandima Devi ◽  
Sethuraman Sathya ◽  
Ana Sanches-Silva ◽  
Listos Joanna ◽  
...  
Keyword(s):  
Tissue Expression ◽  
Health Concern ◽  
Pharmacological Intervention ◽  
Peroxisome Proliferator ◽  
Expression Of Genes ◽  
Ppar Agonists ◽  
Prevalence Of Obesity ◽  
Peroxisome Proliferator Activated Receptors ◽  
Natural And Synthetic

: Obesity is a major health concern for a growing fraction of the population, with the prevalence of obesity and its related metabolic disorders not being fully understood. Over the last decade, many attempts have been undertaken to understand the mechanisms at the basis of this condition, in which the accumulation of fat occurring in adipose tissue, leads to the pathogenesis of obesity related disorders. Among the most recent studies, those on Peroxisome Proliferator Activated Receptors (PPARs) revealed that these nuclear receptor proteins acting as transcription factors, among others, regulate the expression of genes involved in energy, lipid, and glucose metabolisms, and chronic inflammation. The three different isotypes of PPARs, with different tissue expression and ligand binding specificity, exert similar or overlapping functions directly or indirectly linked to obesity. In this study, we reviewed the available scientific reports concerning the PPARs structure and functions, especially in obesity, considering both natural and synthetic ligands and their role in the therapy of obesity and obesity-associated disorders. In the whole, the collected data show that there are both natural and synthetic compounds that show beneficial promising activity as PPAR agonists in chronic diseases related to obesity.

scholarly journals The Role of PPARγinHelicobacter pyloriInfection and Gastric Carcinogenesis

PPAR Research ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Jong-Min Lee ◽  
Sung Soo Kim ◽  
Young-Seok Cho
Keyword(s):  
Gastric Cancer ◽  
Cell Proliferation ◽  
Current Knowledge ◽  
Mucosal Injury ◽  
Gastric Carcinogenesis ◽  
Etiologic Factor ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
H Pylori

Peroxisome proliferator-activated receptorγ(PPARγ) is a nuclear receptor that is important in many physiological and pathological processes, such as lipid metabolism, insulin sensitivity, inflammation, cell proliferation, and carcinogenesis. Several studies have shown that PPARγplays an important role in gastric mucosal injury due toHelicobacter pylori(H. pylori). AsH. pyloriinfection is the main etiologic factor in chronic gastritis and gastric cancer, understanding of the potential roles of PPARγinH. pyloriinfection may lead to the development of a therapeutic target. In this paper, the authors discuss the current knowledge on the role of PPARγinH. pyloriinfection and its related gastric carcinogenesis.

scholarly journals Peroxisome proliferator-activated receptor agonists (PPARs): a promising prospect in the treatment of psoriasis and psoriatic arthritis

2013 ◽  
Vol 88 (6) ◽  
pp. 1029-1035 ◽  
Author(s):  
Emerson de Andrade Lima ◽  
Mariana Modesto Dantas de Andrade Lima ◽  
Cláudia Diniz Lopes Marques ◽  
Angela Luzia Branco Pinto Duarte ◽  
Ivan da Rocha Pita ◽  
...  
Keyword(s):  
Psoriatic Arthritis ◽  
Metabolic Diseases ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Obesity And Diabetes ◽  
Interactive Network ◽  
Increased Risk ◽  
Peroxisome Proliferator Activated Receptors ◽  
Skin Conditions

Psoriasis is a polygenic, inflammatory and progressive disease, characterized by an abnormal differentiation and hyperproliferation of keratinocytes, associated with impaired immunologic activation and systemic disorders, while psoriatic arthritis is a chronic inflammatory articular disease. Pathophysiology of psoriasis comprises a dysfunction of the immune system cells with an interactive network between cells and cytokines supporting the initiation and perpetuation of disease and leading to inflammation of skin, enthesis and joints. Recent studies have shown an important role of systemic inflammation in the development of atherosclerosis. Corroborating these findings, patients with severe Psoriasis have marked incidence of psoriatic arthritis, cardiovascular diseases, hypertension, dyslipidemia, obesity and diabetes mellitus, showing an increased risk for acute myocardial infarction, which suggests that the condition is not restricted to the skin. Nuclear receptors are ligand-dependent transcription factors, whose activation affects genes that control vital processes. Among them the peroxisome proliferator-activated receptor is responsible for establishing the relationship between lipids, metabolic diseases and innate immunity. In the skin, peroxisome proliferator-activated receptors have an important effect in keratinocyte homeostasis, suggesting a role in diseases such as psoriasis. The peroxisome proliferator-activated receptors agonists represent a relevant source of research in the treatment of skin conditions, however more clinical studies are needed to define the potential response of these drugs in patients with psoriasis and psoriatic arthritis.

scholarly journals Role of PPARs in Progression of Anxiety: Literature Analysis and Signaling Pathways Reconstruction

PPAR Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Olga I. Rudko ◽  
Artemii V. Tretiakov ◽  
Elena A. Naumova ◽  
Eugene A. Klimov
Keyword(s):  
Signal Pathway ◽  
Signal Pathways ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Pathway Studio ◽  
Pathway Reconstruction ◽  
Peroxisome Proliferator Activated Receptors ◽  
High Concentrations ◽  
Pathological Anxiety

Peroxisome proliferator-activated receptor (PPAR) group includes three isoforms encoded by PPARG, PPARA, and PPARD genes. High concentrations of PPARs are found in parts of the brain linked to anxiety development, including hippocampus and amygdala. Among three PPAR isoforms, PPARG demonstrates the highest expression in CNS, where it can be found in neurons, astrocytes, and glial cells. Herein, the highest PPARG expression occurs in amygdala. However, little is known considering possible connections between PPARs and anxiety behavior. We reviewed possible connections between PPARs and anxiety. We used the Pathway Studio software (Elsevier). Signal pathways were created according to previously developed algorithms. SNEA was performed in Pathway Studio. Current study revealed 14 PPAR-regulated proteins linked to anxiety. Possible mechanism of PPAR involvement in neuroinflammation protection is proposed. Signal pathway reconstruction and reviewing aimed to reveal possible connection between PPARG and CCK-ergic system was conducted. Said analysis revealed that PPARG-dependent regulation of MME and ACE peptidase expression may affect levels of nonhydrolysed, i.e., active CCK-4. Impairments in PPARG regulation and following MME and ACE peptidase expression impairments in amygdala may be the possible mechanism leading to pathological anxiety development, with brain CCK-4 accumulation being a key link. Literature data analysis and signal pathway reconstruction and reviewing revealed two possible mechanisms of peroxisome proliferator-activated receptors involvement in pathological anxiety: (1) cytokine expression and neuroinflammation mechanism and (2) regulation of peptidases targeted to anxiety-associated neuropeptides, primarily CCK-4, mechanism.

scholarly journals New Insights into the Role of Peroxisome Proliferator-Activated Receptors in Regulating the Inflammatory Response after Tissue Injury

PPAR Research ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Miriam D. Neher ◽  
Sebastian Weckbach ◽  
Markus S. Huber-Lang ◽  
Philip F. Stahel
Keyword(s):  
Inflammatory Response ◽  
Major Trauma ◽  
Tissue Injury ◽  
Ischemia Reperfusion ◽  
Healing Process ◽  
Wound Healing Process ◽  
Peroxisome Proliferator ◽  
Ppar Agonists ◽  
Peroxisome Proliferator Activated Receptors

Major trauma results in a strong inflammatory response in injured tissue. This posttraumatic hyperinflammation has been implied in the adverse events leading to a breakdown of host defense mechanisms and ultimately to delayed organ failure. Ligands to peroxisome proliferator-activated receptors (PPARs) have recently been identified as potent modulators of inflammation in various acute and chronic inflammatory conditions. The main mechanism of action mediated by ligand binding to PPARs is the inhibition of the nuclear transcription factor NF-κB, leading to downregulation of downstream gene transcription, such as for genes encoding proinflammatory cytokines. Pharmacological PPAR agonists exert strong anti-inflammatory properties in various animal models of tissue injury, including central nervous system trauma, ischemia/reperfusion injury, sepsis, and shock. In addition, PPAR agonists have been shown to induce wound healing process after tissue trauma. The present review was designed to provide an up-to-date overview on the current understanding of the role of PPARs in the pathophysiology of the inflammatory response after major trauma. Therapeutic options for using recombinant PPAR agonists as pharmacological agents in the management of posttraumatic inflammation will be discussed.

The Role of Peroxisome Proliferator-Activated Receptor in Addiction: A Novel Drug Target

2021 ◽  
Vol 21 ◽  
Author(s):  
Carla Quiroga ◽  
Juan José Barberena ◽  
Jocelyne Alcaraz-Silva ◽  
Sérgio Machado ◽  
Claudio Imperatori ◽  
...  
Keyword(s):  
Nuclear Receptors ◽  
Acid Oxidation ◽  
Critical Element ◽  
Peroxisome Proliferator ◽  
Addictive Behaviors ◽  
Health Issues ◽  
Peroxisome Proliferator Activated Receptor ◽  
Peroxisome Proliferator Activated Receptors ◽  
Novel Drug

: The peroxisome proliferator activated receptors (PPARs) are a superfamily of well-recognized ligand-binding nuclear receptors comprising three isoforms: PPARα, PPARγ, and PPARβ/δ. In response to endogenous lipid messengers, PPARs trigger the transcription of genes related to a wider spectrum of physiological phenomena, including fatty acid oxidation, inflammation, and adipogenesis among many others. Thus, the importance of PPARs as putative protective therapy in health issues has increased the interest in studying these nuclear receptors, including the management of neurodegenerative disorders, multiple sclerosis, and likely addiction. In recent years, several pieces of evidence from animal models have demonstrated the promising role of PPARs as a critical element for interventions in addictive behaviors by reducing the reinforcing properties of addictive substances such as alcohol. However, there is a lack of data in scope and has so far been unexplored the function of PPARs in additional drugs such as cannabis, opioids, methamphetamine, or cocaine. Similar scenario has been found for the management of binge-type eating disorders. Thus, here we review recent advances in understanding the relevance of the PPAR controlling addiction.

scholarly journals Gastrointestinal Cytoprotection by PPAR Ligands

PPAR Research ◽  
2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Yuji Naito ◽  
Tomohisa Takagi ◽  
Toshikazu Yoshikawa
Keyword(s):  
Immune Response ◽  
Cell Proliferation ◽  
Gastrointestinal Tract ◽  
Current Knowledge ◽  
Peroxisome Proliferator ◽  
Potential Therapeutic Target ◽  
Peroxisome Proliferator Activated Receptor ◽  
Gastrointestinal Inflammation ◽  
Ppar Ligands

Peroxisome proliferator-activated receptor (PPAR) is a nuclear receptor that is known to play a central role in lipid metabolism and insulin sensitivity as well as inflammation and cell proliferation. According to the results obtained from studies on several animal models of gastrointestinal inflammation, PPAR has been implicated in the regulation of the immune response, particularly inflammation control, and has gained importance as a potential therapeutic target in the management of gastrointestinal inflammation. In the present paper, we present the current knowledge on the role of PPAR ligands in the gastrointestinal tract.

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