Mitochondria-dependent apoptosis of con A-activated T lymphocytes induced by asiatic acid for preventing murine fulminant hepatitis

Combinatorial drug-loaded quality by design adapted transliposome gel formulation for dermal delivery: In vitro and dermatokinetic study

BACKGROUND

Ursolic acid is a powerful drug that possesses many therapeutic properties, such as hepatoprotection, immunomodulation, anti-inflammatory, antidiabetic, antibacterial, antiviral, antiulcer, and anticancer activity. Centella asiatica (L.) Urban (Umbelliferae) contains a triterpene called asiatic acid, which has been used effectively in traditional Chinese and Indian medicine system for centuries. Anticancer, anti-inflammatory, and neuroprotective properties are only some of the many pharmacological actions previously attributed to asiatic acid .

AIM

The present work developed an optimized combinatorial drug-loaded nano-formulation by Quality by design approach.

MATERIALS AND METHODS

The optimize transliposome for accentuated dermal delivery of dual drug. The optimization of drug-loaded transliposome was done using the "Box-Behnken design." The optimized formulation was characterized for vesicles size, entrapment efficiency (%), and in vitro drug release. Additionally, transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), and dermatokinetic study were performed for further evaluation of drug-loaded optimized transliposome formulation.

RESULTS

The optimized combinatorial drug-loaded transliposome formulation showed a particle size of 86.36 ± 2.54 nm, polydispersity index (PDI) 0.230 ± 0.008, and an entrapment efficiency of 87.43 ± 2.66% which depicted good entrapment efficiency. In vitro drug release of ursolic acid and asiatic acid transliposomes was found to be 85.12 ± 2.54% and 80.23 ± 3.23%, respectively, as compared to optimized ursolic acid and asiatic acid transliposome gel drug release that was 67.18 ± 2.85% and 60.28 ± 4.12%, respectively. The skin permeation study of ursolic and asiatic acid conventional formulation was only 32.48 ± 2.42%, compared with optimized combinatorial drug-loaded transliposome gel (79.83 ± 4.52%) at 12 h. After applying combinatorial drug-loaded transliposome gel, rhodamine was able to more easily cross rat skin, as observed by confocal laser scanning microscopy, in comparison with when the rhodamine control solution was used.

DISCUSSION

The UA_AA-TL gel formulation absorbed more ursolic acid and asiatic acid than the UA_AA-CF gel formulation, as per dermatokinetic study. Even after being incorporated into transliposome vesicles, the antioxidant effects of ursolic and asiatic acid were still detectable. In most cases, transliposomes vesicular systems generate depots in the skin's deeper layers and gradually release the medicine over time, allowing for fewer applications.

CONCLUSION

In overall our studies, it may be concluded that developed dual drug-loaded transliposomal formulation has great potential for effective topical drug delivery for skin cancer.

1,2,3,4,6-Penta-O-galloyl-d-glucose Interrupts the Early Adipocyte Lifecycle and Attenuates Adiposity and Hepatic Steatosis in Mice with Diet-Induced Obesity

Phytochemicals that interrupt adipocyte lifecycle can provide anti-obesity effects. 1,2,3,4,6-penta-O-galloyl-d-glucose (PGG) is a tannin with two isomers that occurs widely in plants and exhibits various pharmacological activities. The aim of the investigation is to comprehensively examine effects of PGG isomer(s) on adipocyte lifecycle and diet-induced obesity. Human mesenchymal stem cells (hMSC), 3T3-L1 fibroblasts, and H4IIE hepatoma cells were used to determine the effects of PGG isomers on cell viability and adipogenesis. Mice with diet-induced obesity were generated from male C57/BL6 mice fed with a 45% high fat diet. Oral administration of β-PGG (0.1 and 5 mg/kg) lasted for 14 weeks. Viability was reduced by repeated PGG treatment in hMSC, preadipocytes, and cells under differentiation. PGG mainly induces apoptosis, and this effect is independent of its insulin mimetic action. In vivo, administration of β-PGG attenuated shortening of the colon, hyperlipidaemia, fat cells and islet hypertrophy in DIO mice. Hepatic steatosis and related gene expression were improved along with glucose intolerance. Increased serum adiponectin, leptin, and glucagon-like peptide-1 levels were also observed. In conclusion, repeated PGG treatment interrupts the adipocyte lifecycle. PGG administration reduces adiposity and fatty liver development in DIO mice, and therefore, PGG could aid in clinical management of obesity.

Pharmacological Properties, Molecular Mechanisms, and Pharmaceutical Development of Asiatic Acid: A Pentacyclic Triterpenoid of Therapeutic Promise

Asiatic acid (AA) is a naturally occurring aglycone of ursane type pentacyclic triterpenoids. It is abundantly present in many edible and medicinal plants including Centella asiatica that is a reputed herb in many traditional medicine formulations for wound healing and neuropsychiatric diseases. AA possesses numerous pharmacological activities such as antioxidant and anti-inflammatory and regulates apoptosis that attributes its therapeutic effects in numerous diseases. AA showed potent antihypertensive, nootropic, neuroprotective, cardioprotective, antimicrobial, and antitumor activities in preclinical studies. In various in vitro and in vivo studies, AA found to affect many enzymes, receptors, growth factors, transcription factors, apoptotic proteins, and cell signaling cascades. This review aims to represent the available reports on therapeutic potential and the underlying pharmacological and molecular mechanisms of AA. The review also also discusses the challenges and prospects on the pharmaceutical development of AA such as pharmacokinetics, physicochemical properties, analysis and structural modifications, and drug delivery. AA showed favorable pharmacokinetics and found bioavailable following oral or interaperitoneal administration. The studies demonstrate the polypharmacological properties, therapeutic potential and molecular mechanisms of AA in numerous diseases. Taken together the evidences from available studies, AA appears one of the important multitargeted polypharmacological agents of natural origin for further pharmaceutical development and clinical application. Provided the favorable pharmacokinetics, safety, and efficacy, AA can be a promising agent or adjuvant along with currently used modern medicines with a pharmacological basis of its use in therapeutics.

Asiatic acid attenuates lipopolysaccharide-induced injury by suppressing activation of the Notch signaling pathway

Sepsis is a severe multisystem disease with high mortality rates and limited treatment options. However, advances during the last decade have opened opportunities to develop novel therapeutic strategies. The Notch signaling pathway plays a critical role in inflammation, and its inhibition offers an avenue to treat inflammatory diseases, such as sepsis. Asiatic acid (AA), a triterpenoid isolated from Centella asiatica, reportedly exerts anti-oxidant, anti-tumor, and anti-inflammatory effects, but its mechanisms remain unclear. In our study, we found that AA decreased levels of interleukin-1β (IL-1β), IL-6, alanine aminotransferase and blood urea nitrogen in serum; attenuated liver, lung and kidney damage; and improved the survival among mice with experimental sepsis. AA also reduced lipopolysaccharide-stimulated expression of proinflammatory mediators, including nitric oxide, IL-1β and IL-6 in RAW 264.7 macrophages. Notably, we demonstrated for the first time that AA is a novel small molecule inhibitor of the Notch signaling pathway. Its effects include upregulation of Notch receptor (Notch3) and delta-like ligand (DLL4), inhibition of Notch3 binding to the IL-6 promoter and regulation of mitochondrial function. These novel effects of AA may provide new approaches and strategies for the treatment of inflammatory disorders.

Asiatic acid protects against hepatic ischemia/reperfusion injury by inactivation of Kupffer cells via PPARγ/NLRP3 inflammasome signaling pathway

Hepatic ischemia/reperfusion (I/R) contributes to major complications in clinical practice affecting perioperative morbidity and mortality. Recent evidence suggests the key role of nucleotide-binding oligomerization domain-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammaosme activation on the pathogenesis of I/R injury. Asiatic acid (AA) is a pentacyclic triterpene derivative presented with versatile activities, including antioxidant, anti-inflammation and hepatoprotective effects. This study was designed to determine whether AA had potential hepatoprotective benefits against hepatic I/R injury, as well as to unveil the underlying mechanisms involved in the putative effects. Mice subjected to warm hepatic I/R, and Kupffer cells (KCs) or RAW264.7 cells challenged with lipopolysaccharide (LPS)/H₂O₂, were pretreated with AA. Administration of AA significantly attenuated hepatic histopathological damage, global inflammatory level, apoptotic signaling level, as well as NLRP3 inflammasome activation. These effects were correlated with increased expression of peroxisome proliferator-activated receptor gamma (PPARγ). Conversely, pharmacological inhibition of PPARγ by GW9662 abolished the protective effects of AA on hepatic I/R injury and in turn aggravated NLRP3 inflammasome activation. Activation of NLRP3 inflammasome was most significant in nonparenchymal cells (NPCs). Depletion of KCs by gadolinium chloride (GdCl3) further attenuated the detrimental effects of GW9662 on hepatic I/R as well as NLRP3 activation. In vitro, AA concentration-dependently inhibited LPS/H₂O₂-induced NLRP3 inflammaosome activation in KCs and RAW264.7 cells. Either GW9662 or genetic knockdown of PPARγ abolished the AA-mediated inactivation of NLRP3 inflammasome. Mechanistically, AA attenuated I/R or LPS/H₂O₂-induced ROS production and phosphorylation level of JNK, p38 MAPK and IκBα but not ERK, a mechanism dependent on PPARγ. Finally, AA blocked the deleterious effects of LPS/H₂O₂-induced macrophage activation on hepatocyte viability in vitro, and improved survival in a lethal hepatic I/R injury model in vivo. Collectively, these data suggest that AA is effective in mitigating hepatic I/R injury through attenuation of KCs activation via PPARγ/NLRP3 inflammasome signaling pathway.

Protective effect of asiatic acid in an experimental cerulein-induced model of acute pancreatitis in mice

Asiatic acid (AA), a triterpenoid derived from the medicinal plant Centella asiatica, is considered to have anti-inflammatory, anti-fibrotic and anti-tumor effects, but its effects in acute pancreatitis (AP) are unknown. Our purpose of this study was to investigate the effects of AA in a mouse model of cerulein-induced pancreatitis. We evaluated AA in an experimental model of AP induced in mice by six hourly intraperitoneal injections of cerulein 50 µg/kg. Mice were pretreated with vehicle or AA 50 mg/kg 2 h before the first cerulein injection. The severity of AP was evaluated histologically and by biochemistry, myeloperoxidase activity, proinflammatory cytokine production, and nuclear factor (NF)-κB activity. Administration of AA significantly reduced the severity of AP, and was associated with reduction of serum amylase and lipase levels, decreased pancreatic histological damage, and decreased myeloperoxidase activity. The serum levels and mRNA expression of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and NF-κB activity were reduced. AA also significantly improved the in vitro viability of pancreatic acinar cells induced by cholecystokinin (CCK) and suppressed NF-κB activity. AA protected against experimental AP, possibly by reducing production of proinflammatory cytokines via suppression NF-κB activation.

Suppression of adenosine monophosphate-activated protein kinase selectively triggers apoptosis in activated T cells and ameliorates immune diseases

Deficient apoptosis of activated T cells can result in immunological disorders. Molecules associated with energy and metabolisms are suggested to be involved in pathogenesis of immune diseases, but remain uninvestigated. In the present study we reported that glibenclamide exerted a new pharmacological effect on inflammatory responses by selectively triggering apoptosis of activated T cells. Glibenclamide demonstrated an inhibition on activated T lymphocytes, whereas showed no toxicity in the naive cells. This effect was mainly related with its ability to facilitate apoptosis in activated T cells with an up-regulation of cleaved-caspases and cleaved-PARP. Glibenclamide enhanced Fas expression and suppressed the expression of antiapoptotic cellular FLICE-inhibitory protein. The underlying mechanism of glibenclamide was not associated with its classical inhibitory effect on ATP-sensitive potassium channels, but due to a unique suppression on the phosphorylation of 5' adenosine monophosphate-activated protein kinase, which was augmented during T cell activation. An in vivo experiment further demonstrated that glibenclamide ameliorated T-cell-mediated contact hypersensitivity in mice. Altogether, these results suggest that AMPK inhibition by glibenclamide can regulate the survival and death of T lymphocytes and be beneficial for the treatment of autoimmune diseases.

Asiatic acid inhibits lung cancer cell growth in vitro and in vivo by destroying mitochondria

Asiatic acid (AA), a pentacyclic triterpene found in Centella asiatica, displays significant anti-proliferative effects on cancer cells in vitro although the underlying mechanism of this effect remains unknown. This study investigated the efficacy and mechanism of action of AA against lung cancer both in vivo and in vitro. Using the MTT assay, AA was found to induce apoptosis in a dose- and time-dependent manner, an effect enhanced by pretreatment with an autophagy inhibitor. It also elevated expression of microtubule-associated protein 1 light chain 3 (LC3) and decreased the expression of p62. Furthermore, exposure to AA resulted in collapse of the mitochondrial membrane potential and generation of reactive oxygen species (ROS), suggesting mitochondria are the target of AA. In the mouse lung cancer xenograft model, oral administration of AA significantly inhibited tumor volume and weight accompanied by significant apoptosis of lung cancer cells. In addition, it led to a significant decrease in the expression of proliferating cell nuclear antigen (PCNA). In summary, the results show that AA significantly reduces lung cancer cell growth both in vitro and in vivo and that the associated apoptosis is mediated through mitochondrial damage.

Asiatic acid-pectin hydrogel matrix patch transdermal delivery system influences parasitaemia suppression and inflammation reduction in P. berghei murine malaria infected Sprague-Dawley rats

OBJECTIVE

To report the influence of transdermal delivery of asiatic acid (AA) in Plasmodium berghei-infected Sprague Dawley rats on physicochemical changes, %parasitaemia and associated pathophysiology.

METHODS

A topical once-off AA (5, 10, and 20 mg/kg)- or chloroquine (CHQ)-pectin patch was applied on the shaven dorsal neck region of Plasmodium berghei-infected Sprague Dawley rats (90-120 g) on day 7 after infection. Eating and drinking habits, weight changes, malaria effects and %parasitaemia were compared among animal groups over 21 d.

RESULTS

AA-pectin patch application preserved food and water intake together with %weight gain. All animals developed stable parasitaemia (15-20%) by day 7. AA doses suppressed parasitaemia significantly. AA 5 mg/kg patch was most effective. AA and CHQ displayed bimodal time-spaced peaks. CHQ patch had a longer time course to clear parasitaemia.

CONCLUSIONS

AA influences bio-physicochemical changes and parasitaemia suppression in dose dependent manner. In comparison by dose administered, AA has much better efficacy than CHQ. AA may be a useful antimalarial. AA and CHQ displays bimodal peaks suggesting possible synergism if used in combination therapy.

Asiatic acid influences parasitaemia reduction and ameliorates malaria anaemia in P. berghei infected Sprague-Dawley male rats

BACKGROUND

Current malaria treatment is either "anti-parasitic", "anti-infectivity" or both without addressing the pathophysiological derangement (anti-disease aspect) associated with the disease. Asiatic acid is a natural phytochemical with oxidant, antioxidant and anti-inflammatory properties whose effect on malarial and accompanying pathophysiology are yet to be investigated. Asiatic acid influence in P. berghei-infected Sprague Dawley rats on %parasitaemia and malarial anaemia were investigated.

METHODS

Plasmodium berghei-infected rats (90-120 g) were orally administered with Asiatic acid (5, 10, 20 mg/kg) and 30 mg/kg chloroquine as a positive control. Changes in %parasitaemia and haematological parameters in Asiatic acid administered rats were monitored in a 21 day study and compared to controls.

RESULTS

All animals developed stable parasitaemia (15-20 %) by day 7. Asiatic acid doses suppressed parasitaemia, normalised haematological measurements and influenced biophysical characteristics changes. Most positive changes were associated with intragastric administration of 10 mg/kg Asiatic acid dose. Peak %parasitaemia in Asiatic acid administration occurred at days 12 with a shorter time course compared to day 9 for chloroquine (30 mg/kg) treatment with a longer time course.

CONCLUSIONS

Oral Asiatic acid administration influenced %parasitaemia suppression, ameliorated malarial anaemia and increased biophysical properties on infected animals. Asiatic acid may be a replacement alternative for chloroquine treatment with concomitant amelioration of malaria pathophysiology. Due to different action time courses, Asiatic acid and chloroquine may be possible candidates in combination therapy.

Asiatic acid uncouples respiration in isolated mouse liver mitochondria and induces HepG2 cells death

Asiatic acid, one of the triterpenoid components isolated from Centella asiatica, has received increasing attention due to a wide variety of biological activities. To date, little is known about its mechanisms of action. Here we examined the cytotoxic effect of asiatic acid on HepG2 cells and elucidated some of the underlying mechanisms. Asiatic acid induced rapid cell death, as well as mitochondrial membrane potential (MMP) dissipation, ATP depletion and cytochrome c release from mitochondria to the cytosol in HepG2 cells. In mitochondria isolated from mouse liver, asiatic acid treatment significantly stimulated the succinate-supported state 4 respiration rate, dissipated the MMP, increased Ca(2+) release from Ca(2+)-loaded mitochondria, decreased ATP content and promoted cytochrome c release, indicating the uncoupling effect of asiatic acid. Hydrogen peroxide (H2O2) produced by succinate-supported mitochondrial respiration was also significantly inhibited by asiatic acid. In addition, asiatic acid inhibited Ca(2+)-induced mitochondrial swelling but did not induce mitochondrial swelling in hyposmotic potassium acetate medium which suggested that asiatic acid may not act as a protonophoric uncoupler. Inhibition of uncoupling proteins (UCPs) or blockade of adenine nucleotide transporter (ANT) attenuated the effect of asiatic acid on MMP dissipation, Ca(2+) release, mitochondrial respiration and HepG2 cell death. When combined inhibition of UCPs and ANT, asiatic acid-mediated uncoupling effect was noticeably alleviated. These results suggested that both UCPs and ANT partially contribute to the uncoupling properties of asiatic acid. In conclusion, asiatic acid is a novel mitochondrial uncoupler and this property is potentially involved in its toxicity on HepG2 cells.

Pre-infection administration of asiatic acid retards parasitaemia induction in Plasmodium berghei murine malaria infected Sprague-Dawley rats

BACKGROUND

Malaria prevention has remained a critical area in the absence of efficacious vaccines against malaria. Drugs currently used as chemotherapeutics are also used in chemoprophylaxis increasing possible drug resistance. Asiatic acid is a natural phytochemical with oxidant, antioxidant and anti-inflammatory properties with emerging anti-malarial potential. The influence of asiatic acid administration prior to Plasmodium berghei infection of Sprague-Dawley rats on parasitaemia induction is here reported.

METHODS

Sprague-Dawley rats (90-120 g) were administered with asiatic acid (10 mg/kg) 48 h before intraperitoneal infection with P. berghei. Parasitaemia induction and progression, food and water intake as well as weight were compared to 30 mg/kg chloroquine-treated and infected control rats during sub-chronic studies (21 days).

RESULTS

Asiatic acid pre-infection administration preserved food and water intake as well as increase in percentage weight gain of infected animals. In pre-infection treated animals, the pre-patent period was extended to day 6 from 72 h. Asiatic acid suppressed parasitaemia while oral chloroquine (30 mg/kg) did not influence malaria induction.

CONCLUSIONS

Per-oral, pre-infection, asiatic acid administration influenced parasitaemia patency and parasitaemia progression, food, water, and weight gain percentage. This may suggest possible chemoprophylaxis effects of asiatic acid in malaria.

New Alkaloids from Green Vegetable Soybeans and Their Inhibitory Activities on the Proliferation of Concanavalin A-Activated Lymphocytes

A comprehensive phytochemical study of the chemical constituents of green vegetable soybeans resulted in the isolation of two new alkaloids, soyalkaloid A, 1, and isoginsenine, 2, together with four known ones, ginsenine, 3, (1S,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid, 4, (1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid, 5, and indole-3-carboxylic acid, 6. The structures of compounds 1-6 were elucidated on the basis of spectroscopic and chemical analyses. All of the alkaloids were isolated from soybeans for the first time, and compound 1 was a new indole-type alkaloid with a novel carbocyclic skeleton. Their inhibitory activities on the proliferation of concanalin A-activated lymphocytes were assessed by CCK8 assay.

Asiatic acid inhibits cardiac hypertrophy by blocking interleukin-1β-activated nuclear factor-κB signaling in vitro and in vivo

BACKGROUND

Activated interleukin (IL)-1β signaling pathway is closely associated with pathological cardiac hypertrophy. This study investigated whether asiatic acid (AA) could inhibit IL-1β-related hypertrophic signaling, and thus suppressing the development of cardiac hypertrophy.

METHODS

Transverse aortic constriction (TAC) induced cardiac hypertrophy in C57BL/6 mice and cultured neonatal cardiac myocytes stimulated with IL-1β were used to evaluate the role of AA in cardiac hypertrophy. The expression of atrial natriuretic peptide (ANP) was evaluated by quantitative polymerase chain reaction (qPCR) and the nuclear factor (NF)-κB binding activity was measured by electrophoretic mobility shift assays (EMSA).

RESULTS

AA pretreatment significantly attenuated the IL-1β-induced hypertrophic response of cardiomyocytes as reflected by reduction in the cardiomyocyte surface area and the inhibition of ANP mRNA expression. The protective effect of AA on IL-1β-stimulated cardiomyocytes was associated with the reduction of NF-κB binding activity. In addition, AA prevented TAC-induced cardiac hypertrophy in vivo. It was found that AA markedly reduced the excessive expression of IL-1β and ANP, and inhibited the activation of NF-κB in the hypertrophic myocardium.

CONCLUSIONS

Our data suggest that AA may be a novel therapeutic agent for cardiac hypertrophy. The inhibition of IL-1β-activated NF-κB signaling may be the mechanism through which AA prevents cardiac hypertrophy.

Asiatic acid ameliorates dextran sulfate sodium-induced murine experimental colitis via suppressing mitochondria-mediated NLRP3 inflammasome activation

In the present study, the effect of asiatic acid, a natural triterpenoid compound, on murine experimental colitis induced by dextran sulfate sodium (DSS) and its possible mechanism were examined in vivo and vitro. Oral administration of asiatic acid dose-dependently attenuated the loss of body weight and shortening of colon length induced by DSS. The disease activity index, histopathologic scores of musco and myeloperoxidase activity were also significantly reduced by asiatic acid treatment. Protein and mRNA levels of DSS-induced pro-inflammatory cytokines in colon, including TNF-α, IL-1β, IL-6 and IFN-γ, were markedly suppressed by asiatic acid. At the same time, decreased activation of caspase-1 in peritoneal macrophages was detected in asiatic acid-treated mice, which suggested that the NLRP3 inflammasome activation was suppressed. In addition, we also found that asiatic acid dose-dependently inhibited IL-1β secretion, caspase-1 activation as well as inflammasome assembling in vitro. Furthermore, the mechanism of asiatic acid was related to the inhibition of mitochondrial reactive oxygen species generation and prevention of mitochondrial membrane potential collapse. Taken together, our results demonstrate the ability of asiatic acid to inhibit NLRP3 inflammasome activation and its potential usage in the treatment of inflammatory bowel diseases.

Hep-2 cell based indirect immunofluorescence assay for antinuclear antibodies as a potential diagnosis of drug-induced autoimmunity in nonclinical toxicity testing

Antinuclear antibodies (ANAs) are important biomarkers in the diagnosis of autoimmune diseases in humans; however, the diagnostic performance of ANA in nonclinical safety studies are not well understood. Here, we studied the use of ANAs as potential nonclinical biomarkers for drug-induced autoimmunity (DIA) using a Hep-2 based indirect immunofluorescence assay (IFA). Initially, MRL-fas(lpr)/J mice and HgCl₂-treated rats were used as SLE-positive models. Serum samples obtained from 94 normal mice or 204 normal rats aged one to four months served as the negative control. The IFA effectively distinguished ANAs-positive samples in both species with a cut-off titer of 1:100. Brown Norway rats were treated with 450 mg/kg D-penicillamine for 30 consecutive days. ANAs were generated and corresponded with DIA development. Human Hep-2 cells, mice Neuro 2A cells, and Chinese Hamster Lung cells served as antigen from different species, which were found cross-reactive with ANA-positive serum samples from mice, rats, and humans without any differences in diagnosis. This methodology showed no species-specificity for ANA detection. Furthermore, we found approximately 20 percentage of the mice aged seven to eight months demonstrated age-related ANAs, which was consistent with humans. Overall, our findings demonstrated the use of ANA detection using IFA in the nonclinical diagnosis of murine drug-induced autoimmunity, and age-related ANAs should be considered when aged animals are used.

Beauvericin ameliorates experimental colitis by inhibiting activated T cells via downregulation of the PI3K/Akt signaling pathway

Crohn's disease is a common, chronic inflammatory bowel condition characterized by remission and relapse. Accumulating evidence indicates that activated T cells play an important role in this disease. In the present study, we aimed to examine the effect of beauvericin, a natural cyclic peptide, on 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice, which mimics Crohn's disease. Beauvericin significantly reduced weight loss, diarrhea and mortality, accompanied with notable alleviation of macroscopic and microscopic signs. In addition, this compound decreased serum levels of tumor necrosis factor (TNF)-α and interferon (IFN)- γ in a concentration-dependent manner in mice with experimental colitis. These effects of beauvericin are attributed to its inhibition on activated T cells. Flow cytometry and immunoblot assay data showed that beauvericin suppressed T-cell proliferation, activation and IFN-γ-STAT1-T-bet signaling and subsequently led to apoptosis of activated T cells by suppressing Bcl-2 and phosphorylated Bad as well as increasing cleavage of caspase-3, -9, -12 and PARP. Furthermore, inhibition of PI3K/Akt signaling, which was an upstream regulator of cell activation and survival in activated T cells, contributed to the effect of beauvericin. Overall, these results supported beauvericin as a novel drug candidate for the treatment of colonic inflammation mainly by targeting PI3K/Akt in activated T cells.

Advanced glycation end products induce human corneal epithelial cells apoptosis through generation of reactive oxygen species and activation of JNK and p38 MAPK pathways

Advanced Glycation End Products (AGEs) has been implicated in the progression of diabetic keratopathy. However, details regarding their function are not well understood. In the present study, we investigated the effects of intracellular reactive oxygen species (ROS) and JNK, p38 MAPK on AGE-modified bovine serum albumin (BSA) induced Human telomerase-immortalized corneal epithelial cells (HUCLs) apoptosis. We found that AGE-BSA induced HUCLs apoptosis and increased Bax protein expression, decreased Bcl-2 protein expression. AGE-BSA also induced the expression of receptor for advanced glycation end product (RAGE). AGE-BSA-RAGE interaction induced intracellular ROS generation through activated NADPH oxidase and increased the phosphorylation of p47phox. AGE-BSA induced HUCLs apoptosis was inhibited by pretreatment with NADPH oxidase inhibitors, ROS quencher N-acetylcysteine (NAC) or neutralizing anti-RAGE antibodies. We also found that AGE-BSA induced JNK and p38 MAPK phosphorylation. JNK and p38 MAPK inhibitor effectively blocked AGE-BSA-induced HUCLs apoptosis. In addition, NAC completely blocked phosphorylation of JNK and p38 MAPK induced by AGE-BSA. Our results indicate that AGE-BSA induced HUCLs apoptosis through generation of intracellular ROS and activation of JNK and p38 MAPK pathways.

A novel gold nanoparticle-doped polyaniline nanofibers-based cytosensor confers simple and efficient evaluation of T-cell activation

A rapid, easy assay for monitoring dynamics of T-cell activation should help to guide potential medical evaluation of immune responses or immunopathogenesis. Here, we report development of novel electrochemical cytosensors for dynamic analyses of T-cell activation markers on living cells. Gold nanoparticles-doped polyaniline nanofiber (Au/PANI-NFs) composite was greenly prepared by in situ one-step chemical inertness of PANI-NFs with gold nanoparticles to fabricate impedance-based electrochemical biosensors. Transmission electron micrographs indicated that the gold nanoparticles were uniformly anchored along with the structure of PANI-NF surface, displaying fibrillar morphology with a ~60 nm diameter. Au/PANI-NFs-based cytosensors coated with anti-CD Ab molecules could provide biomimetic interface for multiple immunosensing of T-cell surface activation markers (CD69, CD25, and CD71). The dual signal amplification of Au nanoparticle and PANI-NFs-based electrochemical impedance spectroscopic (EIS) measurements enabled the cytosensors considerably sensitive, with a detection limit of 1×10(4) cells/ml of activated T-cells. The activation-targeted cytosensors detected early, middle and late stages for expression of activation markers CD69, CD25, and CD71 at 8 h, 24 h, and 36 h, respectively, after concanvalin A stimulation of T cells. The quantitative results consisted with those derived from flow cytometric analysis. Furthermore, activation-targeted cytosensor allowed for dynamic analysis of the immune inhibition of T-cell activation by immune regulatory drug icariin (ICA). Thus, Au/PANI-NFs-based cytosensors offer simple and fast approach for non-destructive, quantitative evaluation of T-cell activation markers, with considerable specificity, reproducibility, and low background noise.

Peroxisome Proliferator-Activated Receptor Gamma Exacerbates Concanavalin A-Induced Liver Injury via Suppressing the Translocation of NF-κB into the Nucleus

Peroxisome proliferator-activated receptor-γ (PPARγ) has been reported to reduce inflammation and attenuate fibrosis in the liver. In this study, we investigated the effects of PPARγ on the liver injury induced by 20 mg/kg Concanavalin A (Con A). The mice were administered one of the three types of PPARγ ligands (pioglitazone, ciglitazone, and troglitazone) for 1 week, and the serum alanine aminotransferase (ALT) levels at 20 h after Con A injection were significantly elevated in the PPARγ ligand-treated mice. Furthermore, the serum ALT levels after Con A injection in the PPARγ hetero-knock-out mice (PPARγ^+/− mice) were lower than those in the wild-type mice (WT mice). Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) revealed extensive liver damage induced by Con A in the pioglitazone-treated mice. Electrophoresis mobility shift assay (EMSA) revealed that activation of translocation of nuclear factor- (NF-) κB, which is a suppressor of apoptosis, in the nucleus of the hepatocytes was suppressed in the pioglitazone-treated mice after Con A injection. In this study, we showed that PPARγ exacerbated Con A-induced liver injury via suppressing the translocation of NF-κB into the nucleus, thereby inhibiting the suppression of liver cell apoptosis.