Selective inhibition of sphingosine kinase-1 protects adipose tissue against LPS-induced inflammatory response in Zucker diabetic fatty rats

2014 ◽  
Vol 307 (5) ◽  
pp. E437-E446 ◽  
Author(s):  
Monica Tous ◽  
Raquel Ferrer-Lorente ◽  
Lina Badimon
Keyword(s):  
Adipose Tissue ◽  
Inflammatory Response ◽  
Sphingosine Kinase ◽  
Selective Inhibition ◽  
Mrna Levels ◽  
Sphingosine Kinase 1 ◽  
Zucker Diabetic Fatty Rats ◽  
Cc Chemokines ◽  
Interfering Rna

Obesity is associated with a state of chronic inflammation. The chemokine (C-C motif) ligand 5 (CCL5) has been proposed to modulate the inflammatory response in adipose tissue (AT). However, the mechanisms underlying CCL5 upregulation in AT remain undefined. The objective of the present study was to evaluate whether the enzyme sphingosine kinase-1 (SK1) would modulate the expression of CCL5 and other inflammatory biomarkers in primary adipocytes and its potential role in lipopolysaccharide (LPS)-induced AT inflammation in a rat model of diabetes. To address this, LPS-stimulated primary adipocytes and 3T3-L1 cells were treated with a SK inhibitor, and the expression of Ccl5 and other CC chemokines were studied. Moreover, the effect of SK1 knockdown on cytokine production was analyzed in 3T3-L1 cells by transfection of SK1-specific small-interfering RNA (siRNA). The anti-inflammatory effects of SK inhibitor in AT were also investigated in vivo using the Zucker lean normoglycemic control (ZLC) rats. LPS treatment stimulated Ccl5, IL-6, pentraxin 3 ( Ptx3), and Tnfα mRNA expression in primary adipocytes and 3T3-L1 cells, whereas pharmacologically and siRNA-mediated SK1 inhibition strongly reduced mRNA levels of proinflammatory cytokines in these cells. Similarly, administration of SK inhibitor to ZLC rats prevented the LPS-induced inflammatory response in AT. Our data demonstrate a role for SK1 in endotoxin-induced cytokine expression in adipocytes and suggest that inhibition of SK1 may be a potential therapeutic tool in the prevention and treatment of chronic and common metabolic disorders, including obesity, insulin-resistance, and type 2 diabetes.

scholarly journals Basal and angiopoietin-1–mediated endothelial permeability is regulated by sphingosine kinase-1

Blood ◽  
2008 ◽  
Vol 111 (7) ◽  
pp. 3489-3497 ◽  
Author(s):  
Xiaochun Li ◽  
Milena Stankovic ◽  
Claudine S. Bonder ◽  
Christopher N. Hahn ◽  
Michelle Parsons ◽  
...  
Keyword(s):  
Endothelial Permeability ◽  
Sphingosine Kinase ◽  
Dominant Negative ◽  
Sphingosine Kinase 1 ◽  
Sphingosine 1 Phosphate ◽  
Functional States ◽  
Interfering Rna ◽  
Angiopoietin 1

Abstract Endothelial cells (ECs) regulate the barrier function of blood vessels. Here we show that basal and angiopoietin-1 (Ang-1)–regulated control of EC permeability is mediated by 2 different functional states of sphingosine kinase-1 (SK-1). Mice depleted of SK-1 have increased vascular leakiness, whereas mice transgenic for SK-1 in ECs show attenuation of leakiness. Furthermore, Ang-1 rapidly and transiently stimulates SK-1 activity and phosphorylation, and induces an increase in intracellular sphingosine-1-phosphate (S1P) concentration. Overexpression of SK-1 resulted in inhibition of permeability similar to that seen for Ang-1, whereas knockdown of SK-1 by small interfering RNA blocked Ang-1-mediated inhibition of permeability. Transfection with SKS225A, a nonphosphorylatable mutant of SK-1, inhibited basal leakiness, and both SKS225A and a dominant-negative SK-1 mutant removed the capacity of Ang-1 to inhibit permeability. These effects were independent of extracellular S1P as knockdown or inhibition of S1P1, S1P2, or S1P3, did not affect the Ang-1 response. Thus, SK-1 levels in ECs powerfully regulate basal permeability in vitro and in vivo. In addition, the Ang-1–induced inhibition of leakiness is mediated through activation of SK-1, defining a new signaling pathway in the Ang-1 regulation of permeability.

scholarly journals NAG-1/GDF15 Transgenic Mouse Has Less White Adipose Tissue and a Reduced Inflammatory Response

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
J. M. Kim ◽  
J. P. Kosak ◽  
J. K. Kim ◽  
G. Kissling ◽  
D. R. Germolec ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Inflammatory Response ◽  
White Adipose Tissue ◽  
Inflammatory Cytokine ◽  
Cytokine Production ◽  
Mrna Levels ◽  
Intestinal Tumors ◽  
Inflammatory Cytokine Production

NAG-1/GDF15 is a TGF-βsuperfamily member with poorly characterized biological activity proposed to inhibit inflammatory cytokine production. Transgenic mice expressing human NAG-1/GDF15 (NAG-1Tg/Lox) are leaner with lower body weight and are resistant to chemically or genetically induced intestinal tumors. Because of the link between obesity, inflammation, and cancer, we examined whether these mice exhibit a reduced response to inflammatory stimuli. TheNAG-1Tg/Loxmice had a reduced inflammatory response to LPS based on the serum levels of cytokines KC, IL-6, MCP-1, and TNFα. In contrast to literature reports and ourin vivoresults, NAG-1 did not inhibit LPS-induced cytokine expressionin vitroin RAW264.7 cells, mouse peritoneal macrophages, or mouse liver Kupffer cells, suggesting that NAG-1/GDF15 does not directly inhibit LPS-induced inflammatory cytokine production. However,NAG-1Tg/Loxmice have less white adipose tissue, the major source of inflammatory adipokines including leptin. Basal and LPS-treated serum leptin and mRNA levels in the adipose tissue ofNAG-1Tg/Loxmice were lower than those in WT mice. We propose that the reduced white adipose tissue and reduced leptin expression may be responsible, in part, for the reduced inflammatory response to LPS and the decrease in intestinal tumors observed inNAG-1Tg/Loxmice.

scholarly journals DBC1 (Deleted in Breast Cancer 1) modulates the stability and function of the nuclear receptor Rev-erbα

2013 ◽  
Vol 451 (3) ◽  
pp. 453-461 ◽  
Author(s):  
Claudia C. S. Chini ◽  
Carlos Escande ◽  
Veronica Nin ◽  
Eduardo N. Chini
Keyword(s):  
Breast Cancer ◽  
Nuclear Receptor ◽  
Clock Genes ◽  
Mrna Levels ◽  
Protein Levels ◽  
The Stability ◽  
And Function ◽  
Interfering Rna ◽  
In Cells

The nuclear receptor Rev-erbα has been implicated as a major regulator of the circadian clock and integrates circadian rhythm and metabolism. Rev-erbα controls circadian oscillations of several clock genes and Rev-erbα protein degradation is important for maintenance of the circadian oscillations and also for adipocyte differentiation. Elucidating the mechanisms that regulate Rev-erbα stability is essential for our understanding of these processes. In the present paper, we report that the protein DBC1 (Deleted in Breast Cancer 1) is a novel regulator of Rev-erbα. Rev-erbα and DBC1 interact in cells and in vivo, and DBC1 modulates the Rev-erbα repressor function. Depletion of DBC1 by siRNA (small interfering RNA) in cells or in DBC1-KO (knockout) mice produced a marked decrease in Rev-erbα protein levels, but not in mRNA levels. In contrast, DBC1 overexpression significantly enhanced Rev-erbα protein stability by preventing its ubiquitination and degradation. The regulation of Rev-erbα protein levels and function by DBC1 depends on both the N-terminal and C-terminal domains of DBC1. More importantly, in cells depleted of DBC1, there was a dramatic decrease in circadian oscillations of both Rev-erbα and BMAL1. In summary, our data identify DBC1 as an important regulator of the circadian receptor Rev-erbα and proposes that Rev-erbα could be involved in mediating some of the physiological effects of DBC1.

Sphingosine kinase 1 regulates lysyl oxidase through STAT3 in hyperoxia-mediated neonatal lung injury

Thorax ◽  
2021 ◽  
pp. thoraxjnl-2020-216469
Author(s):  
Alison W Ha ◽  
Tao Bai ◽  
David L Ebenezer ◽  
Tanvi Sethi ◽  
Tara Sudhadevi ◽  
...  
Keyword(s):  
Lung Injury ◽  
Lysyl Oxidase ◽  
Critical Role ◽  
Sphingosine Kinase ◽  
In Vivo Studies ◽  
Sphingosine Kinase 1 ◽  
Neonatal Lung ◽  
Neonatal Lung Injury

IntroductionNeonatal lung injury as a consequence of hyperoxia (HO) therapy and ventilator care contribute to the development of bronchopulmonary dysplasia (BPD). Increased expression and activity of lysyl oxidase (LOX), a key enzyme that cross-links collagen, was associated with increased sphingosine kinase 1 (SPHK1) in human BPD. We, therefore, examined closely the link between LOX and SPHK1 in BPD.MethodThe enzyme expression of SPHK1 and LOX were assessed in lung tissues of human BPD using immunohistochemistry and quantified (Halo). In vivo studies were based on Sphk1−/− and matched wild type (WT) neonatal mice exposed to HO while treated with PF543, an inhibitor of SPHK1. In vitro mechanistic studies used human lung microvascular endothelial cells (HLMVECs).ResultsBoth SPHK1 and LOX expressions were increased in lungs of patients with BPD. Tracheal aspirates from patients with BPD had increased LOX, correlating with sphingosine-1-phosphate (S1P) levels. HO-induced increase of LOX in lungs were attenuated in both Sphk1−/− and PF543-treated WT mice, accompanied by reduced collagen staining (sirius red). PF543 reduced LOX activity in both bronchoalveolar lavage fluid and supernatant of HLMVECs following HO. In silico analysis revealed STAT3 as a potential transcriptional regulator of LOX. In HLMVECs, following HO, ChIP assay confirmed increased STAT3 binding to LOX promoter. SPHK1 inhibition reduced phosphorylation of STAT3. Antibody to S1P and siRNA against SPNS2, S1P receptor 1 (S1P1) and STAT3 reduced LOX expression.ConclusionHO-induced SPHK1/S1P signalling axis plays a critical role in transcriptional regulation of LOX expression via SPNS2, S1P1 and STAT3 in lung endothelium.

scholarly journals Lack of adipose-specific hexose-6-phosphate dehydrogenase causes inactivation of adipose glucocorticoids and improves metabolic phenotype in mice

2019 ◽  
Vol 133 (21) ◽  
pp. 2189-2202
Author(s):  
Jian Wang ◽  
Ying Wang ◽  
Limei Liu ◽  
Kabirullah Lutfy ◽  
Theodore C. Friedman ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fasting Blood Glucose ◽  
Visceral Obesity ◽  
Conditional Knockout ◽  
Hormone Sensitive Lipase ◽  
Metabolic Phenotype ◽  
Mrna Levels ◽  
Obesity And Diabetes ◽  
Factor C

Abstract Excessive glucocorticoid (GC) production in adipose tissue promotes the development of visceral obesity and metabolic syndrome (MS). 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is critical for controlling intracellular GC production, and this process is tightly regulated by hexose-6-phosphate dehydrogenase (H6PDH). To better understand the integrated molecular physiological effects of adipose H6PDH, we created a tissue-specific knockout of the H6PDH gene mouse model in adipocytes (adipocyte-specific conditional knockout of H6PDH (H6PDHAcKO) mice). H6PDHAcKO mice exhibited almost complete absence of H6PDH expression and decreased intra-adipose corticosterone production with a reduction in 11β-HSD1 activity in adipose tissue. These mice also had decreased abdominal fat mass, which was paralleled by decreased adipose lipogenic acetyl-CoA carboxylase (ACC) and ATP-citrate lyase (ACL) gene expression and reduction in their transcription factor C/EBPα mRNA levels. Moreover, H6PDHAcKO mice also had reduced fasting blood glucose levels, increased glucose tolerance, and increased insulin sensitivity. In addition, plasma free fatty acid (FFA) levels were decreased with a concomitant decrease in the expression of lipase adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) in adipose tissue. These results indicate that inactivation of adipocyte H6PDH expression is sufficient to cause intra-adipose GC inactivation that leads to a favorable pattern of metabolic phenotypes. These data suggest that H6PDHAcKO mice may provide a good model for studying the potential contributions of fat-specific H6PDH inhibition to improve the metabolic phenotype in vivo. Our study suggests that suppression or inactivation of H6PDH expression in adipocytes could be an effective intervention for treating obesity and diabetes.

Impaired Sphingosine-1-Phosphate Synthesis Induces Preeclampsia by Deactivating Trophoblastic YAP (Yes-Associated Protein) Through S1PR2 (Sphingosine-1-Phosphate Receptor-2)-Induced Actin Polymerizations

Hypertension ◽  
2021 ◽  
Author(s):  
Jiujiang Liao ◽  
Yangxi Zheng ◽  
Mingyu Hu ◽  
Ping Xu ◽  
Li Lin ◽  
...  
Keyword(s):  
Actin Polymerization ◽  
Sphingosine Kinase ◽  
Actin Dynamics ◽  
Extravillous Trophoblast ◽  
Trophoblast Invasion ◽  
Hippo Signaling ◽  
Dependent Manner ◽  
Sphingosine Kinase 1 ◽  
Sphingosine 1 Phosphate

Incomplete spiral artery remodeling, caused by impaired extravillous trophoblast invasion, is a fundamental pathogenic process associated with malplacentation and the development of preeclampsia. Nevertheless, the mechanisms controlling this regulation of trophoblast invasion are largely unknown. We report that sphingosine-1-phosphate synthesis and expression is abundant in healthy trophoblast, whereas in pregnancies complicated by preeclampsia the placentae are associated with reduced sphingosine-1-phosphate and lower SPHK1 (sphingosine kinase 1) expression and activity. In vivo inhibition of sphingosine kinase 1 activity during placentation in pregnant mice led to decreased placental sphingosine-1-phosphate production and defective placentation, resulting in a preeclampsia phenotype. Moreover, sphingosine-1-phosphate increased HTR8/SVneo (immortalized trophoblast cells) cell invasion in a Hippo-signaling–dependent transcriptional coactivator YAP (Yes-associated protein) dependent manner, which is activated by S1PR2 (sphingosine-1-phosphate receptor-2) and downstream RhoA/ROCK induced actin polymerization. Mutation-based YAP-5SA demonstrated that sphingosine-1-phosphate activation of YAP could be either dependent or independent of Hippo signaling. Together, these findings suggest a novel pathogenic pathway of preeclampsia via disrupted sphingosine-1-phosphate metabolism and signaling-induced, interrupted actin dynamics and YAP deactivation; this may lead to potential novel intervention targets for the prevention and management of preeclampsia.

scholarly journals Tart Cherry Reduces Inflammation in Adipose Tissue of Zucker Fatty Rats and Cultured 3T3-L1 Adipocytes

Nutrients ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1576 ◽  
Author(s):  
Shasika Jayarathne ◽  
April Stull ◽  
Alexandra Miranda ◽  
Shane Scoggin ◽  
Kate Claycombe-Larson ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid Synthase ◽  
Related Factor ◽  
Mrna Levels ◽  
Nuclear Factor ◽  
Adipose Tissue Inflammation ◽  
Tart Cherry ◽  
Tissue Inflammation ◽  
Anti Inflammatory

Obesity increases adipose tissue inflammation and secretion of pro-inflammatory adipokines, which have systemic effects on the organism’s health status. Our objective was to dissect mechanisms of anti-inflammatory effects of tart cherry (TC) in adipose tissue of Zucker fatty rats, and cultured 3T3-L1 adipocytes. Rats were fed either a control diet, or 4% TC powder diets for eight weeks. Body and epididymal fat pad weights were not significantly different between control and TC groups. However, rats fed the TC diet had significantly reduced adipose tissue inflammation (p < 0.05), as determined by reduced mRNA levels of pro-inflammatory markers including interleukin-6 (IL-6), tumor necrosis factor alpha (TNFα), interleukin-1beta (IL-1β), monocyte chemoattractant protein 1 (MCP-1), inducible nitric oxide synthase (iNOS), and CD-11b, and increased mRNA levels of type-1 arginase (Arg-1) anti-inflammatory marker. Consistent with these in vivo results, TC significantly decreased expression of IL-6 mRNA and protein levels in lipopolysaccharide (LPS) stimulated adipocytes compared to those stimulated with LPS, but no TC. Moreover, both in vivo (rat adipose tissue) and in vitro (3T3-L1 adipocytes), phosphorylation of p65-NF-κB subunit was significantly reduced by TC. Additionally, TC decreased mRNA expression of fatty acid synthase (FASN), and increased expression of peroxisome proliferator-activated receptor alpha (PPARα), master regulator of lipid oxidation, and anti-oxidant markers nuclear factor erythroid-derived 2-related factor (NRFs) in both models. In conclusion, our findings indicate that TC downregulates inflammation in part via the nuclear factor kappa B (NF-κB) pathway in adipose tissue. Thus, TC may serve as a potential intervention to reduce obesity-associated inflammation.

scholarly journals Expression of peroxisome proliferator-activated receptors in lean and obese Zucker rats

2000 ◽  
pp. 71-78 ◽  
Author(s):  
A Gorla-Bajszczak ◽  
C Siegrist-Kaiser ◽  
O Boss ◽  
AG Burger ◽  
CA Meier
Keyword(s):  
Adipose Tissue ◽  
Fiber Type ◽  
Zucker Rats ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Rnase Protection ◽  
Brown Adipose ◽  
Obese Zucker Rats

OBJECTIVE: Examination of the pattern of expression of peroxisome proliferator-activated receptor (PPAR) isoforms alpha and gamma in a model of obesity. DESIGN: Examination of adipose tissue and primary adipocyte cultures from lean and obese Zucker rats at different ages (28 days and 12 weeks). METHODS: mRNA levels were measured by RNase protection assay.RESULTS: The highest levels of PPARalpha and gamma mRNA were present in brown adipose tissue (BAT), followed by liver and white adipose tissue (WAT) for the alpha and gamma subtypes, respectively, at both ages examined. PPARalpha was expressed 100-fold higher in BAT compared with WAT, and PPARgamma mRNA levels were 2-fold higher in the WAT of obese compared with lean rats. PPARalpha and gamma expression was minimal in m. soleus, although higher levels of PPARgamma were found in the diaphragm. In marked contrast to the findings in vivo, virtually no PPARalpha mRNA could be detected in BAT cultures differentiated in vitro. CONCLUSION: PPARalpha and gamma are most highly expressed in BAT in vivo. However, PPARalpha is undetectable in brown adipose cells in vitro, suggesting that the expression of this receptor is induced by some external stimuli. In addition, the expression of PPARgamma was increased in WAT from young obese animals, compatible with an early adaptive phenomenon. Finally, the presence of PPARgamma mRNA is detectable only in particular muscles, such as the diaphragm, suggesting the possibility of an influence of fiber type on its expression, although exercise did not influence the expression of PPARgamma in other skeletal muscles.

Regulation of adiponectin by adipose tissue-derived cytokines: in vivo and in vitro investigations in humans

2003 ◽  
Vol 285 (3) ◽  
pp. E527-E533 ◽  
Author(s):  
Jens M. Bruun ◽  
Aina S. Lihn ◽  
Camilla Verdich ◽  
Steen B. Pedersen ◽  
Søren Toubro ◽  
...  
Keyword(s):  
Weight Loss ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Mrna Levels ◽  
Plasma Adiponectin ◽  
Tnf Α ◽  
Adiponectin Mrna ◽  
Before And After

Adiponectin is an adipose tissue-specific protein that is abundantly present in the circulation and suggested to be involved in insulin sensitivity and development of atherosclerosis. Because cytokines are suggested to regulate adiponectin, the aim of the present study was to investigate the interaction between adiponectin and three adipose tissue-derived cytokines (IL-6, IL-8, and TNF-α). The study was divided into three substudies as follows: 1) plasma adiponectin and mRNA levels in adipose tissue biopsies from obese subjects [mean body mass index (BMI): 39.7 kg/m2, n = 6] before and after weight loss; 2) plasma adiponectin in obese men (mean BMI: 38.7 kg/m2, n = 19) compared with lean men (mean BMI: 23.4 kg/m2, n = 10) before and after weight loss; and 3) in vitro direct effects of IL-6, IL-8, and TNF-α on adiponectin mRNA levels in adipose tissue cultures. The results were that 1) weight loss resulted in a 51% ( P < 0.05) increase in plasma adiponectin and a 45% ( P < 0.05) increase in adipose tissue mRNA levels; 2) plasma adiponectin was 53% ( P < 0.01) higher in lean compared with obese men, and plasma adiponectin was inversely correlated with adiposity, insulin sensitivity, and IL-6; and 3) TNF-α ( P < 0.01) and IL-6 plus its soluble receptor ( P < 0.05) decreased adiponectin mRNA levels in vitro. The inverse relationship between plasma adiponectin and cytokines in vivo and the cytokine-induced reduction in adiponectin mRNA in vitro suggests that endogenous cytokines may inhibit adiponectin. This could be of importance for the association between cytokines (e.g., IL-6) and insulin resistance and atherosclerosis.

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