Chun-Jung Chen

Protective effect of rutin on LPS-induced acute lung injury via down-regulation of MIP-2 expression and MMP-9 activation through inhibition of Akt phosphorylation.

Lipopolysaccharide (LPS), also called endotoxin, is the important pathogen of acute lung injury (ALI), which is a clinical syndrome that still lacks effective therapeutic medicine. Rutin belongs to vitamin P and possesses various beneficial effects. In this study, we investigate the potential protective effects and the mechanisms of rutin on LPS-induced ALI. Pre-administration with rutin inhibited LPS-induced arterial blood gas exchange and neutrophils infiltration in the lungs. LPS-induced expression of macrophage inflammatory protein (MIP)-2 and activation of matrix metalloproteinase (MMP)-9 were suppressed by rutin. In addition, the inhibitory concentration of rutin on phosphorylation of Akt was similar as MIP-2 expression and MMP-9 activation. In conclusion, rutin is a potential protective agent for ALI via suppressing the blood gas exchange and neutrophil infiltration. The mechanism of rutin is down-regulation of MIP-2 expression and MMP-9 activation through inhibition of Akt phosphorylation.

Protective Effect of Ginkgo biloba leaves extract, EGb761, on Endotoxin-Induced Acute Lung Injury via a JNK- and Akt-Dependent NFκB Pathway

Acute lung injury (ALI) is a clinical syndrome mainly caused by Gram-negative bacteria which is still in need of an effective therapeutic medicine. EGb761, an extract of Ginkgo biloba leaves, has several bioeffects including anti-inflammation, cardioprotection, neuroprotection, and free radical scavenging. Preadministration of EGb761 inhibited lipopolysaccharide (LPS)-induced histopathological changes and exchange of arterial blood gas. In addition, LPS-induced expression of proinflammatory mediators, such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, macrophage inflammatory protein (MIP)-2, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2), were suppressed by EGb761. The activation of nuclear factor (NF)κB, a transcription factor of proinflammatory mediators, and phosphorylation of IκB, an inhibitor of NFκB, were also reduced by EGb761. Furthermore, we found the inhibitory concentration of EGb761 on phosphorylation of JNK and Akt was less than those of ERK and p38 MAPK. In conclusion, EGb761 is a potential protective agent for ALI, possibly via downregulating the JNK- and Akt-dependent NFκB activation pathway.

Wogonin attenuates endotoxin‐induced prostaglandin E2 and nitric oxide production via Src‐ERK1/2‐NFκB pathway in BV‐2 microglial cells

Microglia are the major component of intrinsic brain immune system in neuroinflammation. Although wogonin expresses anti‐inflammatory function in microglia, little is known about the molecular mechanisms of the protective effect of wogonin against microglia activation. The aim of this study was to evaluate how wogonin exerts its anti‐inflammatory function in BV2 microglial cells after LPS/INFγ administration. Wogonin not only inhibited LPS/ INFγ‐induced PGE2 and NO production without affecting cell viability but also exhibited parallel inhibition on LPS/INFγ‐induced expression of iNOS and COX‐2 in the same concentration range. While LPS/INFγ‐induced expression of P‐p65 and P‐IκB was inhibited by wogonin—only weak inhibition on P‐p38 and P‐JNK were observed, whereas it significantly attenuated the P‐ERK1/2 and its upstream activators P‐MEK1/2 and P‐Src in a parallel concentration‐dependent manner. These results indicated that the blockade of PGE2 and NO production by wogonin in LPS/INFγ‐stimulated BV2 cells is attributed mainly to interference in the Src‐MEK1/2‐ERK1/2‐NFκB‐signaling pathway.

Odd Chain Fatty Acids; New Insights of the Relationship Between the Gut Microbiota, Dietary Intake, Biosynthesis and Glucose Intolerance

Recent findings have shown an inverse association between circulating C15:0/C17:0 fatty acids with disease risk, therefore, their origin needs to be determined to understanding their role in these pathologies. Through combinations of both animal and human intervention studies, we comprehensively investigated all possible contributions of these fatty acids from the gut-microbiota, the diet, and novel endogenous biosynthesis. Investigations included an intestinal germ-free study and a C15:0/C17:0 diet dose response study. Endogenous production was assessed through: a stearic acid infusion, phytol supplementation, and a Hacl1−/− mouse model. Two human dietary intervention studies were used to translate the results. Finally, a study comparing baseline C15:0/C17:0 with the prognosis of glucose intolerance. We found that circulating C15:0/C17:0 levels were not influenced by the gut-microbiota. The dose response study showed C15:0 had a linear response, however C17:0 was not directly correlated. The phytol supplementation only decreased C17:0. Stearic acid infusion only increased C17:0. Hacl1−/− only decreased C17:0. The glucose intolerance study showed only C17:0 correlated with prognosis. To summarise, circulating C15:0 and C17:0 are independently derived; C15:0 correlates directly with dietary intake, while C17:0 is substantially biosynthesized, therefore, they are not homologous in the aetiology of metabolic disease. Our findings emphasize the importance of the biosynthesis of C17:0 and recognizing its link with metabolic disease.

Endotoxin‐induced acute lung injury in mice is protected by 5,7‐dihydroxy‐8‐methoxyflavone via inhibition of oxidative stress and HIF‐1α

Up to date, the morbidity and mortality rates of acute lung injury (ALI) still rank high among clinical illnesses. Endotoxin, also called lipopolysaccharide (LPS), induced sepsis is the major cause for ALI. Beneficial biological effects, such as antioxidation, anti‐inflammation, and neuroprotection was found to express by 5,7‐dihydroxy‐8‐methoxyflavone (DHMF). The purpose of present study was to investigate the potential protective effects of DHMF and the possibile mechanisms involved in LPS‐induced ALI. In our experimental model, ALI was induced in mice by intratracheal injection of LPS, and DHMF at various concentrations was injected intraperitoneally for 30 min prior to LPS administration. Pretreatment with DHMF inhibited not only the histolopatholgical changes occurred in lungs but also leukocytes infiltration in LPS‐induced ALI. Decreased activity of antioxidative enzymes (AOE) such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) caused by LPS was reversed by DHMF. LPS‐induced lipid peroxidation HIF‐1α accumulation, NF‐κB phosphorylation, and IκBα degradation were all inhibited by DHMF. In addition, LPS‐induced expression of proinflammatory mediators such as TNF‐α and IL‐1β were also inhibited by 5,7‐dihydroxy‐8‐methoxyflavone. These results suggested that the protective mechanisms of DHMF on endotoxin‐induced ALI might be via up‐regulation of antioxidative enzymes, inhibition of NFκB phosphorylation, and HIF‐1α accumulation.

Hepatoprotective activities of rosmarinic acid against extrahepatic cholestasis in rats

Though rosmarinic acid possesses nutritional, pharmaceutical, and toxic properties and shows therapeutic potential on liver diseases, its therapeutic effects against cholestatic liver diseases have not been proven. Using an extrahepatic cholestasis rat model by bile-duct ligation (BDL), daily oral administration of rosmarinic acid showed improvement effects on liver histology, serum biochemicals, ductular reaction, oxidative stress, inflammation, and fibrosis. Rosmarinic acid alleviated BDL-induced transforming growth factor beta-1 (TGF-β1) production and hepatic collagen deposition, and the anti-fibrotic effects were accompanied by reductions in matrix-producing cells and Smad2/3. BDL rats showed increased hepatic NF-κB/AP-1 activities, inflammatory cell infiltration/accumulation, and cytokine production, and these signs of hepatic inflammation were ameliorated by rosmarinic acid. Mechanistic study revealed an inhibitory effect of rosmarinic acid on the axis of the high mobility group box-1 (HMGB1)/toll-like receptor-4 (TLR4) in BDL rats. Results of cultured hepatic stellate cells further showed the impacts of rosmarinic acid which attenuated TGF-β1-induced stellate cell mitogenic and fibrogenic activation. Our findings support the concept that rosmarinic acid could serve as a hepatoprotective agent, and dietary rosmarinic acid supplementation may be beneficial in terms of improving cholestasis-related liver injury via mechanisms involving resolution of oxidative burden and down-regulation of HMGB1/TLR4, NF-κB, AP-1, and TGF-β1/Smad signaling.

Glechoma hederacea extracts attenuate cholestatic liver injury in a bile duct-ligated rat model

ETHNOPHARMACOLOGICAL RELEVANCE In traditional Chinese medicine, Glechoma hederacea is frequently prescribed to patients with cholelithiasis, dropsy, abscess, diabetes, inflammation, and jaundice. Polyphenolic compounds are main bioactive components of Glechoma hederacea. AIM OF THE STUDY This study was aimed to investigate the hepatoprotective potential of hot water extract of Glechoma hederacea against cholestatic liver injury in rats. MATERIALS AND METHODS Cholestatic liver injury was produced by ligating common bile ducts in Sprague-Dawley rats. Saline and hot water extract of Glechoma hederacea were orally administrated using gastric gavages. Liver tissues and bloods were collected and subjected to evaluation using histological, molecular, and biochemical approaches. RESULTS Using a rat model of cholestasis caused by bile duct ligation (BDL), daily oral administration of Glechoma hederacea hot water extracts showed protective effects against cholestatic liver injury, as evidenced by the improvement of serum biochemicals, ductular reaction, oxidative stress, inflammation, and fibrosis. Glechoma hederacea extracts alleviated BDL-induced transforming growth factor beta-1 (TGF-β1), connective tissue growth factor, and collagen expression, and the anti-fibrotic effects were accompanied by reductions in α-smooth muscle actin-positive matrix-producing cells and Smad2/3 activity. Glechoma hederacea extracts attenuated BDL-induced inflammatory cell infiltration/accumulation, NF-κB and AP-1 activation, and inflammatory cytokine production. Further studies demonstrated an inhibitory effect of Glechoma hederacea extracts on the axis of high mobility group box-1 (HMGB1)/toll-like receptor-4 (TLR4) intracellular signaling pathways. CONCLUSIONS The hepatoprotective, anti-oxidative, anti-inflammatory, and anti-fibrotic effects of Glechoma hederacea extracts seem to be multifactorial. The beneficial effects of daily Glechoma hederacea extracts supplementation were associated with anti-oxidative, anti-inflammatory, and anti-fibrotic potential, as well as down-regulation of NF-κB, AP-1, and TGF-β/Smad signaling, probably via interference with the HMGB1/TLR4 axis.

BisGMA-induced cytotoxicity and genotoxicity in macrophages are attenuated by wogonin via reduction of intrinsic caspase pathway activation.

Bisphenol‐A‐glycidyldimethacrylate (BisGMA) is a frequently used monomer in dental restorative resins. However, BisGMA could leach from dental restorative resins after polymerization leading to inflammation in the peripheral environment. Wogonin, a natural flavone derivative, has several benefits, such as antioxidative, anti‐inflammatory and neuroprotective properties. Pretreatment of macrophage RAW264.7 cells with wogonin inhibited cytotoxicity which is induced by BisGMA in a concentration‐dependent manner. BisGMA induced apoptotic responses, such as redistribution of phosphatidylserine from the internal to the external membrane and DNA fragmentation, were decreased by wogonin in a concentration‐dependent manner. In addition, BisGMA‐induced genotoxicity, which detected by cytokinesis‐blocked micronucleus and single‐cell gel electrophoresis assays, were inhibited by wogonin in a concentration‐dependent manner. Furthermore, wogonin suppressed BisGMA–induced activation of intrinsic caspase pathways, such as caspases‐3 and −8. Parallel trends were observed in inhibition of caspase‐3 and −8 activities, apoptosis, and genotoxicity. These results indicate wogonin suppressed the BisGMA‐induced apoptosis and genotoxicity mainly via intrinsic caspase pathway in macrophages.

Indomethacin induced glioma apoptosis involving ceramide signals.

Abstract Nonsteroidal anti‐inflammatory drugs (NSAIDs) are increasingly implicated in the prevention and treatment of cancers apart from their known inhibitory effects on eicosanoid production. One of the NSAIDs, indomethacin, in particular shows promising antineoplastic outcome against glioma. To extend such finding, we here studied in human H4 and U87 glioma cells the possible involvement of the ceramide/protein phosphatase 2 A (PP2A)/Akt axis in the indomethacin‐induced apoptosis. We found that the induced apoptosis was accompanied by a series of biochemical events, including intracellular ceramide generation, PP2A activation, Akt dephosphorylation, Mcl‐1 and FLICE inhibiting protein (FLIP) transcriptional downregulation, Bax mitochondrial distribution, and caspase 3 activation. Such events were also duplicated with a cell‐permeable C2‐ceramide and Akt inhibitor LY294002. Pharmacological inhibition of ceramide synthase by fumonisin B1 and PP2A by okadaic acid moderately attenuated indomethacin‐induced Akt dephosphorylation along with the apoptosis. Results suggested that the ceramide/PP2A/Akt axis is involved in the apoptosis and a possible cyclooxygenase‐independent target for indomethacin. Furthermore, apoptosis regulatory proteins such as Mcl‐1 and FLIP are potential downstream effectors of this axis and their downregulation could turn on the apoptotic program. HighlightsIndomethacin induced glioma cell apoptosis.Indomethacin increased intracellular ceramide levels.Ceramide induced glioma cell apoptosis.LY294002 induced glioma cell apoptosis.Ceramide/PP2A/Akt/Mcl‐1, FLIP axis involved in indomethacin‐induced apoptosis.

Treadmill exercise alleviated prenatal buprenorphine exposure-induced depression in rats

ABSTRACT Mounting evidence suggests that physical exercise shows health benefits in a range of diseases, including psychiatric disorders. Perinatal opioid exposure produces neurobehavioral abnormality, which includes depression symptoms, in patients and their offspring following chronic use of buprenorphine, a mixed agonist/antagonist with a high affinity to opioid receptors, for pain control. Previously, we demonstrated that prenatal buprenorphine exposure in pregnant Sprague‐Dawley rats starting from gestation day 7 and lasting for 14 days caused the development of depression‐like phenotypes in pups at postnatal day 21. Using the same prenatal buprenorphine exposure model, we further demonstrated that a 4‐week course of moderate treadmill exercise conducted on pups starting from postnatal day 22 improved depression‐like neurobehaviors. Prenatal buprenorphine exposure‐induced neurobehavioral changes were accompanied by reductions of neuronal survival, neural stem cell‐associated genes, plasma level of brain‐derived neurotrophic factor (BDNF) and serotonin, phosphorylated tropomyosin‐related kinase receptor type B (TrkB), phosphorylated extracellular signal‐regulated kinase (ERK), PKA activity, phosphorylated cAMP response element‐binding protein (CREB), and CREB DNA binding activity, as well as elevation of repressor element‐1 silencing transcription factor (REST), oxidative stress, and inflammatory responses. Those changes in parameters of plasma and brain were improved by treadmill exercise. In conclusion, the findings of the current study suggest that a non‐pharmacological option, i.e., moderate treadmill exercise, alleviated the development of depression‐like neurobehaviors by resolving the oxidative and inflammatory burden as well as by enhancing neurochemical and neuroendocrine signaling. HighlightsPrenatal buprenorphine exposure induces depression‐like behavior in weanlings.Treadmill exercise improves depression‐like phenotypes.Treadmill exercise increases expression of neurotrophins and neurotransmitters.Treadmill exercise decreases oxidative stress and inflammation.