Epinephrine-mediated regulation of PDK4 mRNA in rat adipose tissue

Fatty acid reesterification in adipose tissue is dependent on the generation of glycerol 3-phosphate, and, at least in rodent adipose tissue, this appears to occur primarily through glyceroneogenesis. A key enzyme in this process is pyruvate dehydrogenase kinase 4 (PDK4). PDK4 is induced in white adipose tissue by thiazolidinediones (TZDs) and the inhibition or knockdown of PDK4 inhibits TZD-induced increases in glyceroneogenesis. Since TZDs have many unwanted side effects, we were interested in identifying alternative mechanisms that could regulate PDK4 mRNA expression in white adipose tissue. In this regard we hypothesized that exercise, fasting, and epinephrine would increase PDK4 mRNA levels in rat epididymal adipose tissue. We further postulated that the p38 mitogen-activated protein kinase (MAPK) and 5′-AMP-activated protein kinase (AMPK) signaling pathways would control PDK4 mRNA expression in cultured adipose tissue. Exercise, fasting, and in or ex vivo epinephrine treatment increased PDK4 mRNA levels. These perturbations did not increase the expression of PDK1, -2, or -3. Pyruvate dehydrogenase phosphorylation was increased after an overnight fast and 4 h after the cessation of exercise. In cultured adipose tissue, epinephrine increased p38 and AMPK signaling; however, the direct activation of AMPK by AICAR or metformin led to reductions in PDK4 mRNA levels. The p38 inhibitor SB202190 reduced epinephrine-mediated increases in p38 MAPK activation without altering hormone-sensitive lipase or AMPK phosphorylation or attenuating epinephrine-induced increases in lipolysis. Reductions in p38 MAPK signaling were associated with decreases in PDK4 mRNA expression. The inhibition of peroxisome proliferator-activated receptor-γ (PPARγ) also attenuated the induction of PDK4. Our results are the very first to demonstrate an epinephrine-mediated regulation of PDK4 mRNA levels in white adipose tissue and suggest that p38 MAPK and PPARγ could be involved in this pathway.

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GDF5 Promotes White Adipose Tissue Thermogenesis via p38 MAPK Signaling Pathway

DNA and Cell Biology ◽

10.1089/dna.2019.4724 ◽

2019 ◽

Vol 38 (11) ◽

pp. 1303-1312

Author(s):

Wenting Zhang ◽

Xiaohui Wu ◽

Zhou Pei ◽

Wieland Kiess ◽

Yan Yang ◽

...

Keyword(s):

Adipose Tissue ◽

Signaling Pathway ◽

P38 Mapk ◽

White Adipose Tissue ◽

Mapk Signaling ◽

Mapk Signaling Pathway

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Protective effects of baicalin in a Caenorhabditis elegans model of Parkinson’s disease

Toxicology Research ◽

10.1093/toxres/tfaa107 ◽

2021 ◽

Author(s):

Jing Ma ◽

Ranran Wang ◽

Ting Chen ◽

Shaowei Jiang ◽

Ajing Xu

Keyword(s):

Oxidative Stress ◽

Caenorhabditis Elegans ◽

Protein Kinase ◽

Mrna Expression ◽

Signaling Pathway ◽

P38 Mapk ◽

Mapk Signaling ◽

Mapk Signaling Pathway ◽

Related Gene ◽

Apoptosis Related Gene

Abstract Parkinson’s disease (PD) is a common neurodegenerative disorder of the central nervous system. However, the pathogenetic mechanisms of PD are far from understood. The aim of this study was to determine the protective effect of baicalin in a Caenorhabditis elegans model of PD. C. elegans worms were stimulated for 24 h with 6-hydroxydopamine (6-OHDA, 50 mM) and treated with or without baicalin (1, 10, or 100 μM). At all tested concentrations, baicalin improved the reversal and omega turn behavioral phenotypes, as well as the survival, of 6-OHDA-stimulated worms. It also inhibited 6-OHDA-induced oxidative stress by decreasing malondialdehyde levels, increasing superoxide dismutase, glutathione reductase, catalase, and glutathione levels and up-regulating mRNA expression of the antioxidant-related genes sod-1, sod-2, sod-3, daf-2, and daf-16. Additionally, it significantly decreased the expression of the apoptosis-related gene ced-3 and increased that of the anti-apoptosis-related gene ced-9. The expression levels of cleaved caspase-3 and B-cell lymphoma 2 in 6-OHDA-treated worms were reversed by baicalin. Apoptosis was suppressed by 6-OHDA in loss-of-function strains via the p38 mitogen-activated protein kinase (MAPK) signaling pathway. Furthermore, the apoptotic effects of 6-OHDA were blocked in sek-1 and pmk-1 mutants. Finally, the mRNA expression of sek-1 and pmk-1 and the protein expression of p38 MAPK and stress-activated protein kinase/extracellular signal-regulated kinase 1 were up-regulated by 6-OHDA and reversed by baicalin. Baicalin may protect against 6-OHDA injury by inhibiting apoptosis and decreasing oxidative stress through the p38 MAPK signaling pathway.

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Reactive oxygen species-dependent regulation of pyruvate dehydrogenase kinase-4 in white adipose tissue

AJP Cell Physiology ◽

10.1152/ajpcell.00313.2019 ◽

2020 ◽

Vol 318 (1) ◽

pp. C137-C149 ◽

Cited By ~ 3

Author(s):

Logan K. Townsend ◽

Alyssa J. Weber ◽

Pierre-Andre Barbeau ◽

Graham P. Holloway ◽

David C. Wright

Keyword(s):

Gene Expression ◽

Reactive Oxygen Species ◽

Adipose Tissue ◽

White Adipose Tissue ◽

Pyruvate Dehydrogenase ◽

Acute Exercise ◽

Pyruvate Dehydrogenase Kinase ◽

Oxygen Species ◽

Pyruvate Dehydrogenase Kinase 4 ◽

Exercise Induced

Reactive oxygen species (ROS) are important signaling molecules mediating the exercise-induced adaptations in skeletal muscle. Acute exercise also drives the expression of genes involved in reesterification and glyceroneogenesis in white adipose tissue (WAT), but whether ROS play any role in this effect has not been explored. We speculated that exercise-induced ROS would regulate acute exercise-induced responses in WAT. To address this question, we utilized various models to alter redox signaling in WAT. We examined basal and exercise-induced gene expression in a genetically modified mouse model of reduced mitochondrial ROS emission [mitochondrial catalase overexpression (MCAT)]. Additionally, H2O2, various antioxidants, and the β3-adrenergic receptor agonist CL316243 were used to assess gene expression in white adipose tissue culture. MCAT mice have reduced ROS emission from WAT, enlarged WAT depots and adipocytes, and greater pyruvate dehydrogenase kinase-4 ( Pdk4) gene expression. In WAT culture, H2O2 reduced glyceroneogenic gene expression. In wild-type mice, acute exercise induced dramatic but transient increases in Pdk4 and phosphoenolpyruvate carboxykinase ( Pck1) mRNA in both subcutaneous inguinal WAT and epididymal WAT depots, which was almost completely absent in MCAT mice. Furthermore, the induction of Pdk4 and Pck1 in WAT culture by CL316243 was markedly reduced in the presence of antioxidants N-acetyl-cysteine or vitamin E. Genetic and nutritional approaches that attenuate redox signaling prevent exercise- and β-agonist-induced gene expression within WAT. Combined, these data suggest that ROS represent important mediators of gene expression within WAT.

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Interleukin-1α stimulates proinflammatory cytokine expression in human cardiac myofibroblasts

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00372.2009 ◽

2009 ◽

Vol 297 (3) ◽

pp. H1117-H1127 ◽

Cited By ~ 69

Author(s):

Neil A. Turner ◽

Anupam Das ◽

Philip Warburton ◽

David J. O'Regan ◽

Stephen G. Ball ◽

...

Keyword(s):

Protein Kinase ◽

Mrna Expression ◽

Signaling Pathways ◽

P38 Mapk ◽

Proinflammatory Cytokines ◽

Enzyme Linked Immunosorbent Assay ◽

Mrna Levels ◽

Tnf Α ◽

Interleukin 1Α ◽

Cardiac Myofibroblasts

Cardiac myofibroblasts (CMF) play a key role in infarct repair and scar formation following myocardial infarction (MI) and are also an important source of proinflammatory cytokines. We postulated that interleukin-1α (IL-1α), a potential early trigger of acute inflammation post-MI, could stimulate human CMF to express additional proinflammatory cytokines. Furthermore, we hypothesized that these effects may be modulated by the anti-inflammatory cytokine interleukin-10 (IL-10). Human CMF were cultured from atrial biopsies from multiple patients. Interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and cardiotrophin-1 (CT-1) mRNA expression and secretion were measured using quantitative real-time RT-PCR and enzyme-linked immunosorbent assay. IL-1α (0.001–10 ng/ml, 0–6 h) stimulated IL-1β, TNF-α, and IL-6 mRNA expression with distinct temporal and concentration profiles, resulting in increased cytokine secretion. The response to IL-1α was much greater than with TNF-α. Neither IL-1α nor TNF-α treatment modulated CT-1 mRNA expression. Immunoblotting with phosphospecific antibodies revealed that IL-1α stimulated the extracellular signal-regulated kinase (ERK)-1/2, p38 mitogen-activated protein kinase (MAPK), c-Jun NH2-terminal kinase (JNK), phosphatidylinositol 3-kinase (PI 3-kinase)/protein kinase B (Akt), and nuclear factor (NF)-κB signaling pathways. Pharmacological inhibitor studies indicated roles for PI 3-kinase/Akt and NF-κB pathways in mediating IL-1β expression, and for NF-κB and p38 MAPK pathways in mediating TNF-α expression. IL-1α-induced IL-6 mRNA expression was reduced by p38 MAPK inhibition, but increased by ERK and JNK pathway inhibitors. IL-10 produced a consistent but modest reduction in IL-1α-induced IL-6 mRNA levels (not IL-1β or TNF-α), but this was not reflected by reduced IL-6 protein secretion. In conclusion, IL-1α stimulates human CMF to express IL-1β, TNF-α, and IL-6 via specific signaling pathways, responses that are unaffected by IL-10 exposure.

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Metallothionein gene expression and secretion in white adipose tissue

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.2000.279.6.r2329 ◽

2000 ◽

Vol 279 (6) ◽

pp. R2329-R2335 ◽

Cited By ~ 24

Author(s):

Paul Trayhurn ◽

Jacqueline S. Duncan ◽

Anne M. Wood ◽

John H. Beattie

Keyword(s):

Gene Expression ◽

Molecular Weight ◽

Adipose Tissue ◽

White Adipose Tissue ◽

Stromal Vascular Fraction ◽

Low Molecular Weight ◽

Secretory Product ◽

Mrna Levels ◽

Gene Encoding ◽

Adrenoceptor Agonist

White adipose tissue (WAT) has been examined to determine whether the gene encoding metallothionein (MT), a low-molecular-weight stress response protein, is expressed in the tissue and whether MT may be a secretory product of adipocytes. The MT-1 gene was expressed in epididymal WAT, with MT-1 mRNA levels being similar in lean and obese ( ob/ ob) mice. MT-1 mRNA was found in each of the main adipose tissue sites (epididymal, perirenal, omental, subcutaneous), and there was no major difference between depots. Separation of adipocytes from the stromal-vascular fraction of WAT indicated that the MT gene (MT-1 and MT-2) was expressed in adipocytes themselves. Treatment of mice with zinc had no effect on MT-1 mRNA levels in WAT, despite strong induction of MT-1 expression in the liver. MT-1 gene expression in WAT was also unaltered by fasting or norepinephrine. However, administration of a β3-adrenoceptor agonist, BRL-35153A, led to a significant increase in MT-1 mRNA. On differentiation of fibroblastic preadipocytes to adipocytes in primary culture, MT was detected in the medium, suggesting that the protein may be secreted from WAT. It is concluded that WAT may be a significant site of MT production; within adipocytes, MT could play an antioxidant role in protecting fatty acids from damage.

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Anti-echinococcal effect of verapamil involving the regulation of the calcium/calmodulin-dependent protein kinase II response in vitro and in a murine infection model

Parasites & Vectors ◽

10.1186/s13071-021-04618-4 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Hai-Jun Gao ◽

Xu-Dong Sun ◽

Yan-Ping Luo ◽

Hua-Sheng Pang ◽

Xing-Ming Ma ◽

...

Keyword(s):

Protein Kinase ◽

Mrna Expression ◽

Echinococcus Granulosus ◽

Calcium Content ◽

Mrna Levels ◽

Dependent Protein Kinase ◽

Calcium Calmodulin Dependent ◽

Dependent Protein

Abstract Background Echinococcosis, which is caused by the larvae of cestodes of the genus Echinococcus, is a parasitic zoonosis that poses a serious threat to the health of humans and animals globally. Albendazole is the drug of choice for the treatment of echinococcosis, but it is difficult to meet clinical goals with this chemotherapy due to its low cure rate and associated side effects after its long-term use. Hence, novel anti-parasitic targets and effective treatment alternatives are urgently needed. A previous study showed that verapamil (Vepm) can suppress the growth of Echinococcus granulosus larvae; however, the mechanism of this effect remains unclear. The aim of the present study was to gain insight into the anti-echinococcal effect of Vepm on Echinococcus with a particular focus on the regulatory effect of Vepm on calcium/calmodulin-dependent protein kinase II (Ca2+/CaM-CaMKII) in infected mice. Methods The anti-echinococcal effects of Vepm on Echinococcus granulosus protoscoleces (PSC) in vitro and Echinococcus multilocularis metacestodes in infected mice were assessed. The morphological alterations in Echinococcus spp. induced by Vepm were observed by scanning electron microscopy (SEM), and the changes in calcium content in both the parasite and mouse serum and liver were measured by SEM-energy dispersive spectrometry, inductively coupled plasma mass spectrometry and alizarin red staining. Additionally, the changes in the protein and mRNA levels of CaM and CaMKII in infected mice, and in the mRNA levels of CaMKII in E. granulosus PSC, were evaluated after treatment with Vepm by immunohistochemistry and/or real-time quantitative polymerase chain reaction. Results In vitro, E. granulosus PSC could be killed by Vepm at a concentration of 0.5 μg/ml or higher within 8 days. Under these conditions, the ultrastructure of PSC was damaged, and this damage was accompanied by obvious calcium loss and downregulation of CaMKII mRNA expression. In vivo, the weight and the calcium content of E. multilocularis metacestodes from mice were reduced after treatment with 40 mg/kg Vepm, and an elevation of the calcium content in the sera and livers of infected mice was observed. In addition, downregulation of CaM and CaMKII protein and mRNA expression in the livers of mice infected with E. multilocularis metacestodes was found after treatment with Vepm. Conclusions Vepm exerted a parasiticidal effect against Echinococcus both in vitro and in vivo through downregulating the expression of Ca2+/CaM-CaMKII, which was over-activated by parasitic infection. The results suggest that Ca2+/CaM-CaMKII may be a novel drug target, and that Vepm is a potential anti-echinococcal drug for the future control of echinococcosis.

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

Endocrinology ◽

10.1210/en.2008-0505 ◽

2008 ◽

Vol 150 (1) ◽

pp. 169-178 ◽

Cited By ~ 36

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.

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APPL1 mediates adiponectin-stimulated p38 MAPK activation by scaffolding the TAK1-MKK3-p38 MAPK pathway

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00427.2010 ◽

2011 ◽

Vol 300 (1) ◽

pp. E103-E110 ◽

Cited By ~ 59

Author(s):

Xiaoban Xin ◽

Lijun Zhou ◽

Caleb M. Reyes ◽

Feng Liu ◽

Lily Q. Dong

Keyword(s):

Protein Kinase ◽

P38 Mapk ◽

Mapk Pathway ◽

Adaptor Protein ◽

Mapk Signaling ◽

Mitogen Activated Protein Kinase ◽

Scaffolding Protein ◽

Mapk Activation ◽

P38 Mapk Pathway ◽

Mitogen Activated Protein

The adaptor protein APPL1 mediates the stimulatory effect of adiponectin on p38 mitogen-activated protein kinase (MAPK) signaling, yet the underlying mechanism remains unclear. Here we show that, in C2C12 cells, overexpression or suppression of APPL1 enhanced or suppressed, respectively, adiponectin-stimulated p38 MAPK upstream kinase cascade, consisting of transforming growth factor-β-activated kinase 1 (TAK1) and mitogen-activated protein kinase kinase 3 (MKK3). In vitro affinity binding and coimmunoprecipitation experiments revealed that TAK1 and MKK3 bind to different regions of APPL1, suggesting that APPL1 functions as a scaffolding protein to facilitate adiponectin-stimulated p38 MAPK activation. Interestingly, suppressing APPL1 had no effect on TNFα-stimulated p38 MAPK phosphorylation in C2C12 myotubes, indicating that the stimulatory effect of APPL1 on p38 MAPK activation is selective. Taken together, our study demonstrated that the TAK1-MKK3 cascade mediates adiponectin signaling and uncovers a scaffolding role of APPL1 in regulating the TAK1-MKK3-p38 MAPK pathway, specifically in response to adiponectin stimulation.

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Regulation of angiopoietin-like protein 4/fasting-induced adipose factor (Angptl4/FIAF) expression in mouse white adipose tissue and 3T3-L1 adipocytes

British Journal Of Nutrition ◽

10.1017/s0007114507882961 ◽

2008 ◽

Vol 100 (1) ◽

pp. 18-26 ◽

Cited By ~ 35

Author(s):

Sarah Dutton ◽

Paul Trayhurn

Keyword(s):

Skeletal Muscle ◽

Cell Culture ◽

Adipose Tissue ◽

White Adipose Tissue ◽

Culture Medium ◽

Mrna Level ◽

Mrna Levels ◽

Rt Pcr ◽

Before And After ◽

Stimulation Of

Angiopoietin-like protein 4 (Angptl4)/FIAF (fasting-induced adipose factor) was first identified as a target for PPAR and to be strongly induced in white adipose tissue (WAT) by fasting. Here we have examined the regulation of the expression and release of this adipokine in mouse WAT and in 3T3-L1 adipocytes. Angptl4/FIAF expression was measured by RT-PCR and real-time PCR; plasma Angptl4/FIAF and release of the protein in cell culture was determined by western blotting. The Angptl4/FIAF gene was expressed in each of the major WAT depots of mice, the mRNA level in WAT being similar to the liver and much higher (>50-fold) than skeletal muscle. Fasting mice (18 h) resulted in a substantial increase in Angptl4/FIAF mRNA in liver and muscle (9·5- and 21-fold, respectively); however, there was no effect of fasting on Angptl4/FIAF mRNA in WAT and the plasma level of Angptl4/FIAF was unchanged. The Angptl4/FIAF gene was expressed in 3T3-L1 adipocytes before and after differentiation, the level increasing post-differentiation; Angptl4/FIAF was released into the culture medium. Insulin, leptin, dexamethasone, noradrenaline, TNFα and several IL (IL-1β, IL-6, IL-10, IL-18) had little effect on Angptl4/FIAF mRNA levels in 3T3-L1 adipocytes. However, a major stimulation of Angptl4/FIAF expression was observed with rosiglitazone and the inflammatory prostaglandins PGD2 and PGJ2. Angptl4/FIAF does not act as an adipose tissue signal of nutritional status, but is markedly induced by fasting in liver and skeletal muscle.

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