Augmentation of 11beta-hydroxysteroid dehydrogenase type 1 in LPS-activated J774.1 macrophages--role of 11beta-HSD1 in pro-inflammatory properties in macrophages

Macrophage infiltration in obese adipose tissue provokes local inflammation and insulin resistance. Evidence has accumulated that activation of 11beta-HSD1 in adipocytes is critically involved in dysfunction of adipose tissue. However, the potential role of 11beta-HSD1 in macrophages still remains unclear. We here demonstrate that a murine macrophage cell line, J774.1 cells expressed 11beta-HSD1 mRNA and reductase activity, both of which were augmented by lipopolysaccharide (LPS)-induced cell activation. Three kinds of pharmacological inhibition of 11beta-HSD1 in LPS-treated macrophages significantly suppressed the expression and secretion of interleukin 1beta, tumor necrosis factor alpha or monocyte chemoattractant protein 1, thereby highlighting a novel role of 11beta-HSD1 in pro-inflammatory properties of activated macrophages.     

Divergent effect of proteasome inhibition on interleukin-1beta and tumor necrosis factor alpha signaling in human astroglial cells

Impaired functioning of the proteasome pathway is one of the molecular mechanism underlying neurodegenerative changes in Alzheimer's disease. In this study, we report that dysfunction of the proteasome pathway in astroglial cells leads to decreased survival and dysregulation of chemokines by differential regulation of the nuclear factor kappa B and c-jun N-terminal kinase (JNK) pathways. We further demonstrated that proteasome inhibition augmented interleukin-1 beta- and tumor necrosis factor-alpha-induced activation of the IkappaBalpha kinase and MKK4/JNK/c-Jun pathway along with TAK1 activation. These results suggest that impaired function of the proteasome pathway may potentiate the immuno-pathologic role of secondarily activated astrocytes in the brain.     

Inhibition of EGFR attenuates fibrosis and stellate cell activation in diet-induced model of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease. NAFLD begins with steatosis and advances to nonalcoholic steatohepatitis (NASH) and cirrhosis. The molecular mechanisms involved in NAFLD progression are not understood. Based on recent studies showing dysregulation of epidermal growth factor receptor (EGFR) in animal models of liver injury, we sought to determine if inhibition of EGFR mitigates liver fibrosis and HSC activation in NAFLD. We utilized the high fat diet (HFD)-induced murine model of liver injury to study the role of EGFR in NAFLD. The lipid accumulation, oxidative stress, hepatic stellate cell (HSC) activation and matrix deposition were examined in the liver tissues. We also evaluated the EGFR signaling pathway, ROS activation and pro-fibrogenic phenotype in oxidized low density lipoproteins (ox-LDL) challenged cultured HSCs. We demonstrate that EGFR was phosphorylated in liver tissues of HFD murine model of NAFLD. Inhibition of EGFR prevented diet-induced lipid accumulation, oxidative stress, and HSC activation and matrix deposition. In cultured HSCs, we show that ox-LDL caused rapid activation of the EGFR signaling pathway and induce the production of reactive oxygen species. EGFR also mediated HSC activation and promoted a pro-fibrogenic phenotype. In conclusion, our data demonstrate that EGFR plays an important role in NAFLD and is an attractive target for NAFLD therapy.     

Fatty acids uptake and oxidation are increased in the liver of rats with adjuvant-induced arthritis

Severe rheumatoid cachexia is associated with pronounced loss of muscle and fat mass in patients with advanced rheumatoid arthritis. This condition is associated with dyslipidemia and predisposition to cardiovascular diseases. Circulating levels of triglycerides (TG) and free fatty acids (FFA) have not yet been consistently defined in severe arthritis. Similarly, the metabolism of these lipids in the arthritic liver has not yet been clarified. Aiming at filling these gaps this study presents a characterization of the circulating lipid profile and of the fatty acids uptake and metabolism in perfused livers of rats with adjuvant-induced arthritis. The levels of TG and total cholesterol were reduced in both serum (10–20%) and liver (20–35%) of arthritic rats. The levels of circulating FFA were 40% higher in arthritic rats, possibly in consequence of cytokine-induced adipose tissue lipolysis. Hepatic uptake and oxidation of palmitic and oleic acids was higher in arthritic livers. The phenomenon results possibly from a more oxidized state of the arthritic liver. Indeed, NADPH/NADP⁺ and NADH/NAD⁺ ratios were 30% lower in arthritic livers, which additionally presented higher activities of the citric acid cycle driven by both endogenous and exogenous FFA. The lower levels of circulating and hepatic TG possibly are caused by an increased oxidation associated to a reduced synthesis of fatty acids in arthritic livers. These results reveal that the lipid hepatic metabolism in arthritic rats presents a strong catabolic tendency, a condition that should contribute to the marked cachexia described for arthritic rats and possibly for the severe rheumatoid arthritis.     

Natural products as modulators of the nuclear receptors and metabolic sensors LXR,FXR and RXR

Nuclear receptors (NRs) represent attractive targets for the treatment of metabolic syndrome-related diseases. In addition, natural products are an interesting pool of potential ligands since they have been refined under evolutionary pressure to interact with proteins or other biological targets.This review aims to briefly summarize current basic knowledge regarding the liver X (LXR) and farnesoid X receptors (FXR) that form permissive heterodimers with retinoid X receptors (RXR). Natural product-based ligands for these receptors are summarized and the potential of LXR, FXR and RXR as targets in precision medicine is discussed.     

The role of metallothionein in oncogenesis and cancer prognosis

The antiapoptotic, antioxidant, proliferative, and angiogenic effects of metallothionein (MT)-I+II has resulted in increased focus on their role in oncogenesis, tumor progression, therapy response, and patient prognosis. Studies have reported increased expression of MT-I+II mRNA and protein in various human cancers; such as breast, kidney, lung, nasopharynx, ovary, prostate, salivary gland, testes, urinary bladder, cervical, endometrial, skin carcinoma, melanoma, acute lymphoblastic leukemia (ALL), and pancreatic cancers, where MT-I+II expression is sometimes correlated to higher tumor grade/stage, chemotherapy/radiation resistance, and poor prognosis. However, MT-I+II are downregulated in other types of tumors (e.g. hepatocellular, gastric, colorectal, central nervous system (CNS), and thyroid cancers) where MT-I+II is either inversely correlated or unrelated to mortality. Large discrepancies exist between different tumor types, and no distinct and reliable association exists between MT-I+II expression in tumor tissues and prognosis and therapy resistance. Furthermore, a parallel has been drawn between MT-I+II expression as a potential marker for prognosis, and MT-I+II's role as oncogenic factors, without any direct evidence supporting such a parallel. This review aims at discussing the role of MT-I+II both as a prognostic marker for survival and therapy response, as well as for the hypothesized role of MT-I+II as causal oncogenes.     

Systemic expression of inflammatory mediators in patients with chronic rhinosinusitis and nasal polyps with and without Aspirin Exacerbated Respiratory Disease

BackgroundSystemic reactions are related to the pathogenesis of Aspirin Exacerbated Respiratory Disease (AERD). With this work we wanted to study the changes in the systemic levels of inflammatory mediators in both baseline and after oral aspirin challenge in patients with and without AERD.MethodsPatients with nasal polyposis and asthma with AERD (n = 20) and without (n = 18) were orally challenged with aspirin in a single-blind placebo controlled study. Serum samples and urine were collected before and 6 h after placebo and aspirin oral challenges. Serum levels of inflammatory mediators were assayed by using the Luminex technology and ELISA. The concentrations of 9-alpha, 11-beta prostaglandin F₂, and leukotriene E₄ (uLTE₄) were measured in urine samples by ELISA. The expression of T-cell surface markers was analyzed in peripheral blood mononuclear cells isolated before and after the challenges.ResultsAERD patients showed significantly higher baseline levels of s-IL-5R-alpha, uLTE₄ and percentage of CD4⁺CD25⁺CD127^pos and CD4⁺CD45RA⁻CD45RO⁺ but decreased levels of TGF-β₁ and number of CD4⁺CD25⁺CD127^neg cells. Aspirin challenge induced the release of uLTE₄, IL-6 and increased the number of CD4⁺CD45RA⁻CD45RO⁺ memory T-cells only in AERD patients but failed to reduce the levels of sCD40L as observed in non-AERD subjects. Further, IL-8 and sIL-5R-alpha levels directly correlated with the PD₂₀ASA and the effects of aspirin on IL-6 and number of memory T-cells was more pronounced in subjects showing more strong reaction (bronchial and nasal).ConclusionsAERD patients have a differential baseline inflammatory pattern that supports the role inflammation as underlying mechanism of the disease. Systemic response to oral aspirin challenge was related to an increase in serum IL-6 and the number of circulating memory T-cells in AERD patients.     

Crosstalk of tight junction components with signaling pathways

Tight junctions (TJs) regulate the passage of ions and molecules through the paracellular pathway in epithelial and endothelial cells. TJs are highly dynamic structures whose degree of sealing varies according to external stimuli, physiological and pathological conditions. In this review we analyze how the crosstalk of protein kinase C, protein kinase A, myosin light chain kinase, mitogen-activated protein kinases, phosphoinositide 3-kinase and Rho signaling pathways is involved in TJ regulation triggered by diverse stimuli. We also report how the phosphorylation of the main TJ components, claudins, occludin and ZO proteins, impacts epithelial and endothelial cell function.     

Uncaria rhynchophylla and rhynchophylline improved kainic acid-induced epileptic seizures via IL-1β and brain-derived neurotrophic factor

Uncaria rhynchophylla (UR) has been used for the treatment of convulsions and epilepsy in traditional Chinese medicine. This study reported the major anti-convulsive signaling pathways and effective targets of UR and rhynchophylline (RP) using genomic and immunohistochemical studies. Epileptic seizure model was established by intraperitoneal injection of kainic acid (KA) in rats. Electroencephalogram and electromyogram recordings indicated that UR and RP improved KA-induced epileptic seizures. Toll-like receptor (TLR) and neurotrophin signaling pathways were regulated by UR in both cortex and hippocampus of KA-treated rats. KA upregulated the expression levels of interleukin-1β (IL-1β) and brain-derived neurotrophin factor (BDNF), which were involved in TLR and neurotrophin signaling pathways, respectively. However, UR and RP downregulated the KA-induced IL-1β and BDNF gene expressions. Our findings suggested that UR and RP exhibited anti-convulsive effects in KA-induced rats via the regulation of TLR and neurotrophin signaling pathways, and the subsequent inhibition of IL-1β and BDNF gene expressions.     

Fucoidan exerts antidepressant-like effects in mice via regulating the stability of surface AMPARs

The inflammatory hypothesis is one of the most important mechanisms of depression. Fucoidan is a bioactive sulfated polysaccharide abundant in brown seaweeds with anti-inflammatory activity. However, the antidepressant effects of fucoidan on chronic stress-induced depressive-like behaviors have not been well elucidated. Here, we used two different depressive-like mouse models, lipopolysaccharide (LPS) and chronic restraint stress (CRS) models, to explore the detailed molecular mechanism underlying its antidepressant-like effects in C57BL/6J mice by combining multiple behavioral, molecular and immunofluorescence experiments. Adenovirus-mediated overexpression of caspase-1 and pharmacological inhibitors were also used to clarify the antidepressant mechanisms of fucoidan. We found that acute administration of fucoidan did not produce antidepressant effects in the tail suspension test (TST) and forced swim test (FST). Interestingly, chronic fucoidan administration not only dose-dependently reduced stress-induced depressive-like behaviors in the TST, FST, sucrose preference test (SPT), and novelty-suppressed feeding test (NSFT), but also alleviated the downregulation of brain-derived neurotrophic factor (BDNF)-dependent synaptic plasticity via inhibiting caspase-1-mediated inflammation in the hippocampus of mice. Moreover, fucoidan significantly ameliorated behavioral and synaptic plasticity abnormalities in the overexpression of caspase-1 in the hippocampus of mice. Furthermore, blocking BDNF abolished the antidepressant-like effects of fucoidan in mice. Therefore, our findings clearly indicate that fucoidan provides a potential supplementary noninvasive treatment for depression by inhibition of hippocampal inflammation.     

Glutamine-Fructose-6-Phosphate Transaminase 2 (GFPT2) Is Upregulated in Breast Epithelial–Mesenchymal Transition and Responds to Oxidative Stress

Breast cancer cells that have undergone partial epithelial–mesenchymal transition (EMT) are believed to be more invasive than cells that have completed EMT. To study metabolic reprogramming in different mesenchymal states, we analyzed protein expression following EMT in the breast epithelial cell model D492 with single-shot LFQ supported by a SILAC proteomics approach. The D492 EMT cell model contains three cell lines: the epithelial D492 cells, the mesenchymal D492M cells, and a partial mesenchymal, tumorigenic variant of D492 that overexpresses the oncogene HER2. The analysis classified the D492 and D492M cells as basal-like and D492HER2 as claudin-low. Comparative analysis of D492 and D492M to tumorigenic D492HER2 differentiated metabolic markers of migration from those of invasion. Glutamine-fructose-6-phosphate transaminase 2 (GFPT2) was one of the top dysregulated enzymes in D492HER2. Gene expression analysis of the cancer genome atlas showed that GFPT2 expression was a characteristic of claudin-low breast cancer. siRNA-mediated knockdown of GFPT2 influenced the EMT marker vimentin and both cell growth and invasion in vitro and was accompanied by lowered metabolic flux through the hexosamine biosynthesis pathway (HBP). Knockdown of GFPT2 decreased cystathionine and sulfide:quinone oxidoreductase (SQOR) in the transsulfuration pathway that regulates H₂S production and mitochondrial homeostasis. Moreover, GFPT2 was within the regulation network of insulin and EGF, and its expression was regulated by reduced glutathione (GSH) and suppressed by the oxidative stress regulator GSK3-β. Our results demonstrate that GFPT2 controls growth and invasion in the D492 EMT model, is a marker for oxidative stress, and associated with poor prognosis in claudin-low breast cancer.