Glucocorticoid reamplification within cells intensifies NF-κB and MAPK signaling and reinforces inflammation in activated preadipocytes

2010 ◽  
Vol 298 (5) ◽  
pp. E930-E940 ◽  
Author(s):  
Takako Ishii-Yonemoto ◽  
Hiroaki Masuzaki ◽  
Shintaro Yasue ◽  
Sadanori Okada ◽  
Chisayo Kozuka ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Reductase Activity ◽  
Stromal Vascular Fraction ◽  
Mapk Signaling ◽  
Obese Mice ◽  
Monocyte Chemoattractant Protein 1 ◽  
Protein Levels ◽  
Fat Depots ◽  
Tnf Α

Increased expression and activity of the intracellular glucocorticoid-reactivating enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) contribute to dysfunction of adipose tissue. Although the pathophysiological role of 11β-HSD1 in mature adipocytes has long been investigated, its potential role in preadipocytes still remains obscure. The present study demonstrates that the expression of 11β-HSD1 in preadipocyte-rich stromal vascular fraction (SVF) cells in fat depots from ob/ob and diet-induced obese mice was markedly elevated compared with lean control. In 3T3-L1 preadipocytes, the level of mRNA and reductase activity of 11β-HSD1 was augmented by TNF-α, IL-1β, and LPS, with a concomitant increase in inducible nitric oxide synthase (iNOS), monocyte chemoattractant protein-1 (MCP-1), or IL-6 secretion. Pharmacological inhibition of 11β-HSD1 and RNA interference against 11β-HSD1 reduced the mRNA and protein levels of iNOS, MCP-1, and IL-6. In contrast, overexpression of 11β-HSD1 further augmented TNF-α-induced iNOS, IL-6, and MCP-1 expression. Moreover, 11β-HSD1 inhibitors attenuated TNF-α-induced phosphorylation of NF-κB p65 and p38-, JNK-, and ERK1/2-MAPK. Collectively, the present study provides novel evidence that inflammatory stimuli-induced 11β-HSD1 in activated preadipocytes intensifies NF-κB and MAPK signaling pathways and results in further induction of proinflammatory molecules. Not limited to 3T3-L1 preadipocytes, we also demonstrated that the notion was reproducible in the primary SVF cells from obese mice. These findings highlight an unexpected, proinflammatory role of reamplified glucocorticoids within preadipocytes in obese adipose tissue.

scholarly journals Inhibition of Ceramide De Novo Synthesis Affects Adipocytokine Secretion and Improves Systemic and Adipose Tissue Insulin Sensitivity

2018 ◽  
Vol 19 (12) ◽  
pp. 3995 ◽  
Author(s):  
Agnieszka U. Blachnio-Zabielska ◽  
Hady Razak Hady ◽  
Adam R. Markowski ◽  
Adam Kurianiuk ◽  
Alicja Karwowska ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
De Novo ◽  
Tolerance Test ◽  
Hormone Sensitive Lipase ◽  
Enzyme Linked Immunosorbent Assay ◽  
Oral Glucose ◽  
Necrosis Factor Alpha ◽  
Fat Depots ◽  
Tnf Α

Ceramide accumulation in muscle and in liver is implicated in the induction of insulin resistance. Much less in known about the role of ceramide in adipose tissue. The aim of the present study was to elucidate the role of ceramide in adipose tissue and to clarify whether lipids participate in the regulation of adipocytokine secretion. The experiments were performed on male Wistar rats divided into three groups: 1. Control, 2. fed high fat diet (HFD), and 3. fed HFD and treated with myriocin. Ceramide (Cer) and diacylglycerol (DAG) content were analyzed by LC/MS/MS. Hormone sensitive lipase (HSL) phosphorylation was analyzed by Western Blot. Plasma adiponectin and tumor necrosis factor alpha (TNF-α) concentration were measured by enzyme-linked immunosorbent assay. An oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) was also performed. In HFD group, total DAG and Cer content was elevated in both subcutaneous and visceral adipose tissue, which was accompanied by increased glucose, insulin, and HOMA-IR value. Myriocin treatment restored HOMA-IR as well as glucose and insulin concentration to control values. Moreover, myriocin decreased not only Cer, but also DAG levels in both fat depots. Furthermore, we observed a strong correlation between adiponectin (negative) and TNF-α (positive) and Cer in both fat tissues, which suggests that Cer is involved in the regulation of adipocytokine secretion.

Role of the TNF pathway in the progression of diabetic nephropathy in KK-Ay mice

2014 ◽  
Vol 306 (11) ◽  
pp. F1335-F1347 ◽  
Author(s):  
Keisuke Omote ◽  
Tomohito Gohda ◽  
Maki Murakoshi ◽  
Yu Sasaki ◽  
Saiko Kazuno ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Early Stage ◽  
Mrna Levels ◽  
Monocyte Chemoattractant Protein 1 ◽  
Protein Levels ◽  
Tnf Α ◽  
Soluble Tnf Receptor

Chronic inflammation promotes the progression of diabetic nephropathy (DN). However, the role of TNF-α remains unclear. The objectives of the present study were to examine whether TNF-α inhibition with a soluble TNF receptor (TNFR)2 fusion protein, i.e., etanercept (ETN), improves the early stage of DN in the type 2 diabetic model of the KK-Ay mouse and to also investigate which TNF pathway, TNFR1 or TNFR2, is predominantly involved in the progression of this disease. ETN was injected intraperitoneally into mice for 8 wk. Renal damage was evaluated by immunohistochemistry, Western blot analysis, and/or real-time PCR. In vitro, mouse tubular proximal cells were stimulated by TNF-α and/or high glucose (HG) and treated with ETN. ETN dramatically improved not only albuminuria but also glycemic control. Renal mRNA and/or protein levels of TNFR2, but not TNF-α and TNFR1, in ETN-treated KK-Ay mice were significantly decreased compared with untreated KK-Ay mice. mRNA levels of ICAM-1, VCAM-1, and monocyte chemoattractant protein-1 and the number of F4/80-positive cells were all decreased after treatment. Numbers of cleaved caspase-3- and TUNEL-positive cells in untreated mice were very few and were not different from ETN-treated mice. In vitro, stimulation with TNF-α or HG markedly increased both mRNA levels of TNFRs, unlike in the in vivo case. Furthermore, ETN partly recovered TNF-α-induced but not HG-induced TNFR mRNA levels. In conclusion, it appears that ETN may improve the progression of the early stage of DN predominantly through inhibition of the anti-inflammatory action of the TNF-α-TNFR2 pathway.

Hypoxia is a potential risk factor for chronic inflammation and adiponectin reduction in adipose tissue of ob/ob and dietary obese mice

2007 ◽  
Vol 293 (4) ◽  
pp. E1118-E1128 ◽  
Author(s):  
Jianping Ye ◽  
Zhanguo Gao ◽  
Jun Yin ◽  
Qing He
Keyword(s):  
Adipose Tissue ◽  
Chronic Inflammation ◽  
Potential Role ◽  
Gene Promoter ◽  
Obese Mice ◽  
Probe Signal ◽  
Hypoxia Response ◽  
Tnf Α ◽  
Partial Oxygen

Chronic inflammation and reduced adiponectin are widely observed in the white adipose tissue in obesity. However, the cause of the changes remains to be identified. In this study, we provide experimental evidence that hypoxia occurs in adipose tissue in obese mice and that adipose hypoxia may contribute to the endocrine alterations. The adipose hypoxia was demonstrated by a reduction in the interstitial partial oxygen pressure (Po2), an increase in the hypoxia probe signal, and an elevation in expression of the hypoxia response genes in ob/ ob mice. The adipose hypoxia was confirmed in dietary obese mice by expression of hypoxia response genes. In the adipose tissue, hypoxia was associated with an increased expression of inflammatory genes and decreased expression of adiponectin. In dietary obese mice, reduction in body weight by calorie restriction was associated with an improvement of oxygenation and a reduction in inflammation. In cell culture, inflammatory cytokines were induced by hypoxia in primary adipocytes and primary macrophages of lean mice. The transcription factor NF-κB and the TNF-α gene promoter were activated by hypoxia in 3T3-L1 adipocytes and NIH3T3 fibroblasts. In addition, adiponectin expression was reduced by hypoxia, and the reduction was observed in the gene promoter in adipocytes. These data suggest a potential role of hypoxia in the induction of chronic inflammation and inhibition of adiponectin in the adipose tissue in obesity.

scholarly journals Nutritional, hormonal, and depot-dependent regulation of the expression of the small GTPase Rab18 in rodent adipose tissue

2012 ◽  
Vol 50 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Marina R Pulido ◽  
Yoana Rabanal-Ruiz ◽  
Farid Almabouada ◽  
Alberto Díaz-Ruiz ◽  
María A Burrell ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Time Course ◽  
Stromal Vascular Fraction ◽  
Small Gtpase ◽  
Female Rats ◽  
Obese Mice ◽  
Adrenergic Stimulation ◽  
Adult Rats ◽  
Protein Levels ◽  
Male And Female Rats

There is increasing evidence that proteins associated with lipid droplets (LDs) play a key role in the coordination of lipid storage and mobilization in adipocytes. The small GTPase, RAB18, has been recently identified as a novel component of the protein coat of LDs and proposed to play a role in both β-adrenergic stimulation of lipolysis and insulin-induced lipogenesis in 3T3-L1 adipocytes. In order to better understand the role of Rab18 in the regulation of lipid metabolism in adipocytes, we evaluated the effects of age, fat location, metabolic status, and hormonal milieu onRab18expression in rodent white adipose tissue (WAT).Rab18mRNA was undetectable at postnatal day 15 (P15), but reached adult levels by P45, in both male and female rats. In adult rats,Rab18immunolocalized around LDs, as well as within the cytoplasm of mature adipocytes. A weakRab18signal was also detected in the stromal-vascular fraction of WAT. In mice, fasting significantly increased, though with a distinct time–course pattern,Rab18mRNA and protein levels in visceral and subcutaneous WAT. The expression ofRab18was also increased in visceral and subcutaneous WAT of obese mice (diet-induced,ob/ob, and New Zealand obese mice) compared with lean controls.Rab18expression in rats was unaltered by castration, adrenalectomy, or GH deficiency but was increased by hypophysectomy, as well as hypothyroidism. When viewed together, our results suggest the participation ofRab18in the regulation of lipid processing in adipose tissue under both normal and pathological conditions.

scholarly journals Skullcapflavone II Suppresses TNF-α/IFN-γ-Induced TARC, MDC, and CTSS Production in HaCaT Cells

2021 ◽  
Vol 22 (12) ◽  
pp. 6428
Author(s):  
Hanon Lee ◽  
Dong Hun Lee ◽  
Jang-Hee Oh ◽  
Jin Ho Chung
Keyword(s):  
P38 Mapk ◽  
Therapeutic Potential ◽  
Inflammatory Diseases ◽  
Mapk Signaling ◽  
Hacat Cells ◽  
Protein Levels ◽  
Tnf Α ◽  
Ifn Γ ◽  
Mapk Signaling Pathways ◽  
Pro Inflammatory Cytokines

Skullcapflavone II (SFII), a flavonoid derived from Scutellaria baicalensis, has been reported to have anti-inflammatory properties. However, its therapeutic potential for skin inflammatory diseases and its mechanism are unknown. Therefore, this study aimed to investigate the effect of SFII on TNF-α/IFN-γ-induced atopic dermatitis (AD)-associated cytokines, such as thymus- and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC). Co-stimulation with TNF-α/IFN-γ in HaCaT cells is a well-established model for induction of pro-inflammatory cytokines. We treated cells with SFII prior to TNF-α/IFN-γ-stimulation and confirmed that it significantly inhibited TARC and MDC expression at the mRNA and protein levels. Additionally, SFII also inhibited the expression of cathepsin S (CTSS), which is associated with itching in patients with AD. Using specific inhibitors, we demonstrated that STAT1, NF-κB, and p38 MAPK mediate TNF-α/IFN-γ-induced TARC and MDC, as well as CTSS expression. Finally, we confirmed that SFII significantly suppressed TNF-α/IFN-γ-induced phosphorylation of STAT1, NF-κB, and p38 MAPK. Taken together, our study indicates that SFII inhibits TNF-α/IFN-γ-induced TARC, MDC, and CTSS expression by regulating STAT1, NF-κB, and p38 MAPK signaling pathways.

scholarly journals Let-7a-5p regulates the inflammatory response in chronic rhinosinusitis with nasal polyps

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jianwei Zhang ◽  
Lei Han ◽  
Feng Chen
Keyword(s):  
Inflammatory Response ◽  
Chronic Rhinosinusitis ◽  
Nasal Polyps ◽  
Mapk Pathway ◽  
Inhibitory Effect ◽  
Luciferase Reporter ◽  
Western Blot Assay ◽  
Protein Levels ◽  
Tnf Α

Abstract Background Let-7a-5p is demonstrated to be a tumor inhibitor in nasopharyngeal carcinoma. However, the role of let-7a-5p in chronic rhinosinusitis with nasal polyps (CRSwNP) has not been reported. This study is designed to determine the pattern of expression and role of let-7a-5p in CRSwNP. Methods The expression level of let-7a-5p, TNF-α, IL-1β, and IL-6 in CRSwNP tissues and cells were detected by RT-qPCR. Western blot assay was carried out to measure the protein expression of the Ras-MAPK pathway. Dual luciferase reporter assay and RNA pull-down assay were used to explore the relationship between let-7a-5p and IL-6. Results Let-7a-5p was significantly downregulated in CRSwNP tissues and cells. Moreover, the mRNA expression of TNF-α, IL-1β and IL-6 was increased in CRSwNP tissues, while let-7a-5p mimic inhibited the expression of TNF-α, IL-1β and IL-6. Besides that, let-7a-5p was negatively correlated with TNF-α, IL-1β and IL-6 in CRSwNP tissues. In our study, IL-6 was found to be a target gene of let-7a-5p. Additionally, let-7-5p mimic obviously reduced the protein levels of Ras, p-Raf1, p-MEK1 and p-ERK1/2, while IL-6 overexpression destroyed the inhibitory effect of let-7a-5p on the Ras-MAPK pathway in CRSwNP. Conclusion We demonstrated that let-7a-5p/IL-6 interaction regulated the inflammatory response through the Ras-MAPK pathway in CRSwNP.

Irisin exerts dual effects on browning and adipogenesis of human white adipocytes

2016 ◽  
Vol 311 (2) ◽  
pp. E530-E541 ◽  
Author(s):  
Yuan Zhang ◽  
Chao Xie ◽  
Hai Wang ◽  
Robin M. Foss ◽  
Morgan Clare ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Uncoupling Protein ◽  
Adipogenic Differentiation ◽  
Mapk Signaling ◽  
Cellular Energy ◽  
Subcutaneous White Adipose Tissue ◽  
Basal Expression ◽  
White Adipocytes ◽  
Ucp1 Expression

To better understand the role of irisin in humans, we examined the effects of irisin in human primary adipocytes and fresh human subcutaneous white adipose tissue (scWAT). Human primary adipocytes derived from 28 female donors' fresh scWAT were used to examine the effects of irisin on browning and mitochondrial respiration, and preadipocytes were used to examine the effects of irisin on adipogenesis and osteogenesis. Cultured fragments of scWAT and perirenal brown fat were used for investigating signal transduction pathways that mediate irisin's browning effect by Western blotting to detect phosphorylated forms of p38, ERK, and STAT3 as well as uncoupling protein 1 (UCP1). Individual responses to irisin in scWAT were correlated with basal expression levels of brown/beige genes. Irisin upregulated the expression of browning-associated genes and UCP1 protein in both cultured primary mature adipocytes and fresh adipose tissues. It also significantly increased thermogenesis at 5 nmol/l by elevating cellular energy metabolism (OCR and ECAR). Treating human scWAT with irisin increased UCP1 expression by activating the ERK and p38 MAPK signaling. Blocking either pathway with specific inhibitors abolished irisin-induced UCP1 upregulation. However, our results showed that UCP1 in human perirenal adipose tissue was insensitive to irisin. Basal levels of brown/beige and FNDC5 genes correlated positively with the browning response of scWAT to irisin. In addition, irisin significantly inhibited adipogenic differentiation but promoted osteogenic differentiation. We conclude that irisin promotes “browning” of mature white adipocytes by increasing cellular thermogenesis, whereas it inhibits adipogenesis and promotes osteogenesis during lineage-specific differentiation. Our findings provide a rationale for further exploring the therapeutic use of irisin in obesity and exercise-associated bone formation.

scholarly journals Macrophage migration inhibitory factor may play a protective role in osteoarthritis

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Ming Liu ◽  
Zikun Xie ◽  
Guang Sun ◽  
Liujun Chen ◽  
Dake Qi ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Migration Inhibitory Factor ◽  
Macrophage Migration Inhibitory Factor ◽  
Protective Role ◽  
Macrophage Migration ◽  
Chain Reaction ◽  
Protein Levels ◽  
Tnf Α ◽  
Polymerase Chain

Abstract Background Osteoarthritis (OA) is the most prevalent form of arthritis and the major cause of disability and overall diminution of quality of life in the elderly population. Currently there is no cure for OA, partly due to the large gaps in our understanding of its underlying molecular and cellular mechanisms. Macrophage migration inhibitory factor (MIF) is a procytokine that mediates pleiotropic inflammatory effects in inflammatory diseases such as rheumatoid arthritis (RA) and ankylosing spondylitis (AS). However, data on the role of MIF in OA is limited with conflicting results. We undertook this study to investigate the role of MIF in OA by examining MIF genotype, mRNA expression, and protein levels in the Newfoundland Osteoarthritis Study. Methods One hundred nineteen end-stage knee/hip OA patients, 16 RA patients, and 113 healthy controls were included in the study. Two polymorphisms in the MIF gene, rs755622, and -794 CATT5-8, were genotyped using polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) and PCR followed by automated capillary electrophoresis, respectively. MIF mRNA levels in articular cartilage and subchondral bone were measured by quantitative polymerase chain reaction. Plasma concentrations of MIF, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β) were measured by enzyme-linked immunosorbent assay. Results rs755622 and -794 CATT5-8 genotypes were not associated with MIF mRNA or protein levels or OA (all p ≥ 0.19). MIF mRNA level in cartilage was lower in OA patients than in controls (p = 0.028) and RA patients (p = 0.004), while the levels in bone were comparable between OA patients and controls (p = 0.165). MIF protein level in plasma was lower in OA patients than in controls (p = 3.01 × 10−10), while the levels of TNF-α, IL-6 and IL-1β in plasma were all significantly higher in OA patients than in controls (all p ≤ 0.0007). Multivariable logistic regression showed lower MIF and higher IL-1β protein levels in plasma were independently associated with OA (OR per SD increase = 0.10 and 8.08; 95% CI = 0.04–0.19 and 4.42–16.82, respectively), but TNF-α and IL-6 became non-significant. Conclusions Reduced MIF mRNA and protein expression in OA patients suggested MIF might have a protective role in OA and could serve as a biomarker to differentiate OA from other joint disorders.

scholarly journals Phospholipase C-ε signaling mediates endothelial cell inflammation and barrier disruption in acute lung injury

2016 ◽  
Vol 311 (2) ◽  
pp. L517-L524 ◽  
Author(s):  
Kaiser M. Bijli ◽  
Fabeha Fazal ◽  
Spencer A. Slavin ◽  
Antony Leonard ◽  
Valerie Grose ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Phospholipase C ◽  
Phorbol Esters ◽  
Critical Determinant ◽  
Monocyte Chemoattractant Protein 1 ◽  
Barrier Disruption ◽  
Proinflammatory Mediators ◽  
Tnf Α

Phospholipase C-ε (PLC-ε) is a unique PLC isoform that can be regulated by multiple signaling inputs from both Ras family GTPases and heterotrimeric G proteins and has primary sites of expression in the heart and lung. Whereas the role of PLC-ε in cardiac function and pathology has been documented, its relevance in acute lung injury (ALI) is unclear. We used PLC-ε−/− mice to address the role of PLC-ε in regulating lung vascular inflammation and injury in an aerosolized bacterial LPS inhalation mouse model of ALI. PLC-ε−/− mice showed a marked decrease in LPS-induced proinflammatory mediators (ICAM-1, VCAM-1, TNF-α, IL-1β, IL-6, macrophage inflammatory protein 2, keratinocyte-derived cytokine, monocyte chemoattractant protein 1, and granulocyte-macrophage colony-stimulating factor), lung neutrophil infiltration and microvascular leakage, and loss of VE-cadherin compared with PLC-ε+/+ mice. These data identify PLC-ε as a critical determinant of proinflammatory and leaky phenotype of the lung. To test the possibility that PLC-ε activity in endothelial cells (EC) could contribute to ALI, we determined its role in EC inflammation and barrier disruption. RNAi knockdown of PLC-ε inhibited NF-κB activity in response to diverse proinflammatory stimuli, thrombin, LPS, TNF-α, and the nonreceptor agonist phorbol 13-myristate 12-acetate (phorbol esters) in EC. Depletion of PLC-ε also inhibited thrombin-induced expression of NF-κB target gene, VCAM-1. Importantly, PLC-ε knockdown also protected against thrombin-induced EC barrier disruption by inhibiting the loss of VE-cadherin at adherens junctions and formation of actin stress fibers. These data identify PLC-ε as a novel regulator of EC inflammation and permeability and show a hitherto unknown role of PLC-ε in the pathogenesis of ALI.

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