scholarly journals Liver apoptosis is age dependent and is reduced by activation of peroxisome proliferator-activated receptor-γ in hemorrhagic shock

2010 ◽  
Vol 298 (1) ◽  
pp. G133-G141 ◽  
Author(s):  
Basilia Zingarelli ◽  
Ranjit Chima ◽  
Michael O'Connor ◽  
Giovanna Piraino ◽  
Alvin Denenberg ◽  
...  

A clinical observation in pediatric and adult intensive care units is that the incidence of multiple organ failure in pediatric trauma victims is lower than in adult patients. However, the molecular mechanisms are not yet defined. Recent experimental studies have shown that the nuclear peroxisome proliferator-activated receptor-γ (PPARγ) modulates the inflammatory process. In this study, we hypothesized that severity of liver injury may be age dependent and PPARγ activation may provide beneficial effects. Hemorrhagic shock was induced in anesthetized young (3–5 mo old) and mature male Wistar rats (11–13 mo old) by withdrawing blood to a mean arterial blood pressure of 50 mmHg. After 3 h, rats were rapidly resuscitated with shed blood. Animals were euthanized 3 h after resuscitation. In mature rats, liver injury appeared more pronounced compared with young rats and was characterized by marked hepatocyte apoptosis, extravasation of erythrocytes, and accumulation of neutrophils. The ratio between the antiapoptotic protein Bcl-2 and the proapoptotic protein BAX was lower, whereas activity of caspase-3, the executioner of apoptosis, was higher in liver of mature rats compared with young rats. Plasma alanine aminotransferase levels were not different between the two age groups. This heightened liver apoptosis was associated with a significant downregulation of PPARγ DNA binding in mature rats compared with young rats. Treatment with the PPARγ ligand ciglitazone significantly reduced liver apoptosis in mature rats. Our data suggest that liver injury after severe hemorrhage is age dependent and PPARγ activation is a novel hepatoprotective mechanism.

PPAR Research ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Wenwen Wang ◽  
Kan Chen ◽  
Yujing Xia ◽  
Wenhui Mo ◽  
Fan Wang ◽  
...  

Objective. Previous studies have characterized the hepatoprotective and anti-inflammatory properties of oleanolic acid (OA). This study aimed to investigate the molecular mechanisms of OA hepatoprotection in concanavalin A- (ConA-) induced acute liver injury.Materials and Methods. ConA (20 mg/kg) was intravenously injected to induce acute liver injury in Balb/C mice. OA pretreatment (20, 40, and 80 mg/kg) was administered subcutaneously once daily for 3 consecutive days prior to treatment with ConA; 2, 8, and 24 h after ConA injection, the levels of serum liver enzymes and the histopathology of major factors and inflammatory cytokines were determined.Results. OA reduced the release of serum liver enzymes and inflammatory factors and prevented ConA mediated damage to the liver. OA elevated the expression levels of peroxisome proliferator-activated receptor alpha (PPARα) and decreased the phosphorylation of c-Jun NH2-terminal kinase (JNK).Conclusion. OA exhibits anti-inflammatory properties during ConA-induced acute liver injury by attenuating apoptosis and autophagy through activation of PPARαand downregulation of JNK signaling.


2020 ◽  
Vol 21 (18) ◽  
pp. 6969
Author(s):  
Young Sup Woo ◽  
Hyun Kook Lim ◽  
Sheng-Min Wang ◽  
Won-Myong Bahk

Close connections between depression and type 2 diabetes (T2DM) have been suggested by many epidemiological and experimental studies. Disturbances in insulin sensitivity due to the disruption of various molecular pathways cause insulin resistance, which underpins many metabolic disorders, including diabetes, as well as depression. Several anti-hyperglycemic agents have demonstrated antidepressant properties in clinical trials, probably due to their action on brain targets based on the shared pathophysiology of depression and T2DM. In this article, we review reports of clinical trials examining the antidepressant effect of these medications, including insulin, metformin, glucagon like peptide-1 receptor agonists (GLP-1RA), and peroxisome proliferator-activated receptor (PPAR)-γ agonists, and briefly consider possible molecular mechanisms underlying the associations between amelioration of insulin resistance and improvement of depressive symptoms. In doing so, we intend to suggest an integrative perspective for understanding the pathophysiology of depression.


2021 ◽  
Vol 128 (7) ◽  
pp. 1021-1039 ◽  
Author(s):  
Shi Fang ◽  
M. Christine Livergood ◽  
Pablo Nakagawa ◽  
Jing Wu ◽  
Curt D. Sigmund

Nuclear receptors represent a large family of ligand-activated transcription factors which sense the physiological environment and make long-term adaptations by mediating changes in gene expression. In this review, we will first discuss the fundamental mechanisms by which nuclear receptors mediate their transcriptional responses. We will focus on the PPAR (peroxisome proliferator-activated receptor) family of adopted orphan receptors paying special attention to PPARγ, the isoform with the most compelling evidence as an important regulator of arterial blood pressure. We will review genetic data showing that rare mutations in PPARγ cause severe hypertension and clinical trial data which show that PPARγ activators have beneficial effects on blood pressure. We will detail the tissue- and cell-specific molecular mechanisms by which PPARs in the brain, kidney, vasculature, and immune system modulate blood pressure and related phenotypes, such as endothelial function. Finally, we will discuss the role of placental PPARs in preeclampsia, a life threatening form of hypertension during pregnancy. We will close with a viewpoint on future research directions and implications for developing novel therapies.


2006 ◽  
Vol 154 (1) ◽  
pp. 159-166 ◽  
Author(s):  
M Messager ◽  
C Carrière ◽  
X Bertagna ◽  
Y de Keyzer

Objective: ACTH is frequently produced in non-pituitary tumours, leading to the ectopic-ACTH syndrome, but the molecular mechanisms of its expression remain obscure. This study was aimed at understanding the transcription mechanisms of the ACTH-precursor gene in carcinoid tumours of the lung or thymus. Design: Transcripts coding for a series of corticotroph-associated transcription factor genes were detected, together with markers of the corticotroph phenotype. We studied a series of 41 carcinoid tumours including 15 with proven ectopic-ACTH syndrome. Methods: Specific RT-PCR reactions were designed for each gene including alternatively spliced isoforms. Results: The markers of the corticotroph phenotype were detected in all ACTH-positive tumours. Expression of the Tpit and Pitx1 genes were not restricted to ACTH-positive tumours but were also detected in many ACTH-negative carcinoids. Only a subset of ACTH-negative tumours expressed NAK-1/Nur77, and NeuroD1 expression was detected in <50% of the tumours regardless of their secretory status. The glucocorticoid receptor alpha was detected in every tumour in contrast to its beta isoform detectable in a few tumours only. Chicken ovalbumin upstream promoter-transcription factor 1 (COUP-TF1) and peroxisome proliferator-activated receptor (PPAR) γ2 were expressed in 50% of the tumours of each group whereas PPARγ1 was expressed in almost every tumour. Conclusions: ACTH-positive carcinoids do not share a characteristic expression pattern of the corticotroph-associated transcription factor genes, suggesting that the transcriptional mechanisms of the ACTH-precursor gene differ from those in normal pituitary corticotrophs. Expression of Tpit and Pitx1 genes in most carcinoids suggests that some aspects of the pituitary corticotroph phenotype may belong to general carcinoid differentiation.


2018 ◽  
Vol 239 (3) ◽  
pp. 289-301 ◽  
Author(s):  
Rita Sharma ◽  
Quyen Luong ◽  
Vishva M Sharma ◽  
Mitchell Harberson ◽  
Brian Harper ◽  
...  

Growth hormone (GH) has long been known to stimulate lipolysis and insulin resistance; however, the molecular mechanisms underlying these effects are unknown. In the present study, we demonstrate that GH acutely induces lipolysis in cultured adipocytes. This effect is secondary to the reduced expression of a negative regulator of lipolysis, fat-specific protein 27 (FSP27; aka Cidec) at both the mRNA and protein levels. These effects are mimicked in vivo as transgenic overexpression of GH leads to a reduction of FSP27 expression. Mechanistically, we show GH modulation of FSP27 expression is mediated through activation of both MEK/ERK- and STAT5-dependent intracellular signaling. These two molecular pathways interact to differentially manipulate peroxisome proliferator-activated receptor gamma activity (PPARγ) on the FSP27 promoter. Furthermore, overexpression of FSP27 is sufficient to fully suppress GH-induced lipolysis and insulin resistance in cultured adipocytes. Taken together, these data decipher a molecular mechanism by which GH acutely regulates lipolysis and insulin resistance in adipocytes.


Reproduction ◽  
2021 ◽  
Vol 161 (5) ◽  
pp. 523-537
Author(s):  
Shi-Yu An ◽  
Zi-Fei Liu ◽  
El-Samahy M A ◽  
Ming-Tian Deng ◽  
Xiao-Xiao Gao ◽  
...  

Long ncRNAs regulate a complex array of fundamental biological processes, while its molecular regulatory mechanism in Leydig cells (LCs) remains unclear. In the present study, we established the lncRNA LOC102176306/miR-1197-3p/peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PPARGC1A) regulatory network by bioinformatic prediction, and investigated its roles in goat LCs. We found that lncRNA LOC102176306 could efficiently bind to miR-1197-3p and regulate PPARGC1A expression in goat LCs. Downregulation of lncRNA LOC102176306 significantly supressed testosterone (T) synthesis and ATP production, decreased the activities of antioxidant enzymes and mitochondrial complex I and complex III, caused the loss of mitochondrial membrane potential, and inhibited the proliferation of goat LCs by decreasing PPARGC1A expression, while these effects could be restored by miR-1197-3p inhibitor treatment. In addition, miR-1197-3p mimics treatment significantly alleviated the positive effects of lncRNA LOC102176306 overexpression on T and ATP production, antioxidant capacity and proliferation of goat LCs. Taken together, lncRNA LOC102176306 functioned as a sponge for miR-1197-3p to maintain PPARGC1A expression, thereby affecting the steroidogenesis, cell proliferation and oxidative stress of goat LCs. These findings extend our understanding of the molecular mechanisms of T synthesis, cell proliferation and oxidative stress of LCs.


2021 ◽  
Vol 21 (7) ◽  
pp. 3943-3949
Author(s):  
Jaegoo Yeon ◽  
Sung-Suk Suh ◽  
Ui-Joung Youn ◽  
Badamtsetseg Bazarragchaa ◽  
Ganbold Enebish ◽  
...  

Iris bungei Maxim. (IB), which is native to China and Mongolia, is used as a traditional medicine for conditions such as inflammation, cancer, and bacterial infections. However, the effects of Iris bungei Maxim. on adipocyte differentiation have not been studied. In the present study, we first demonstrated the molecular mechanisms underlying the adipogenic activity of the methanol extract of Mongolian I. bungei Maxim. (IB). IB significantly enhanced intracellular lipid accumulation and adipocyte differentiation in 3T3-L1 preadipocytes in a concentration-dependent manner. Moreover, IB markedly stimulated the expression of genes related to adipogenesis such as peroxisome proliferator-activated receptor γ, adiponectin, and aP2. In addition, we also observed that IB induces lipogenic genes such as fatty acid synthase, sterol regulatory element binding protein 1c, stearoyl-CoA desaturase, and acetyl-CoA carboxylase. Interestingly IB regulated adipocyte differentiation in both the early and middle stages. Taken together, these adipogenic and lipogenic effects of IB suggest its efficacy for the prevention and/or treatment of type 2 diabetes.


2019 ◽  
Vol 133 (3) ◽  
pp. 531-544 ◽  
Author(s):  
Tzu-Hao Li ◽  
Ying-Ying Yang ◽  
Chia-Chang Huang ◽  
Chih-Wei Liu ◽  
Hung-Cheng Tsai ◽  
...  

Abstract Background: Reversal of alcohol-induced peroxisome proliferator-activated receptor (PPAR) α (PPARα) and PPARδ dysfunction has been reported to decrease the severity of alcoholic steatohepatitis (ASH). Autophagy is essential for cell survival and tissue energy homeostasis. Emerging evidence indicates that alcohol-induced adipose tissue (AT) autophagy dysfunction contributes to injury in the intestine, liver, and AT of ASH. Methods: The effects and mechanisms of dual PPARα/δ agonist elafibranor on autophagy stimulation were investigated using mice with ASH. Results: C57BL/6 mice on ethanol diet showed AT dysfunction, disrupted intestinal barrier, and ASH, which was accompanied by alcohol-mediated decrease in PPARα, PPARδ, and autophagy levels in intestine, liver, and AT. Chronic treatment with elafibranor attenuated AT apoptosis and inflammation by restoration of tissue PPARα, PPARδ, and autophagy levels. In ASH mice, alcohol-induced AT dysfunction along with increased fatty acid (FA) uptake and decreased free FA (FFA) release from AT was inhibited by elafibranor. The improvement of AT autophagy dysfunction by elafibranor alleviated inflammation and apoptosis-mediated intestinal epithelial disruption in ASH mice. Acute elafibranor incubation inhibited ethanol-induced ASH-mice-sera-enhanced autophagy dysfunction, apoptosis, barrier disruption, and intracellular steatosis in Caco-2 cells and primary hepatocytes (PHs). Conclusion: Altogether, these findings demonstrated that the PPARα/δ agonist, elafibranor, decreased the severity of liver injury by restoration of alcohol-suppressed AT autophagy function and by decreasing the release of apoptotic markers, inflammatory cytokines, and FFA, thereby reducing intestinal epithelium disruption and liver inflammation/apoptosis/steatosis in ASH mice. These data suggest that dual PPAR agonists can serve as potential therapeutic agents for the management of ASH.


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