The anti-inflammatory effects of the tellurium redox modulating compound, AS101, are associated with regulation of NFkappaB signaling pathway and nitric oxide induction in macrophages

Mesenchymal stem cells improve cardiac function in diabetic rats by reducing cardiac injury biomarkers and downregulating JAK/STAT/iNOS and iNOS/Apoptosis signaling pathways

Cardiovascular complications are prevalent manifestations of type 2 diabetes mellitus (T2DM) and are usually the main cause of death. This study aims to show the underlying mechanisms of the potential therapeutic effect of mesenchymal stem cells (MSCs) on diabetic cardiac dysfunction. Twenty-four male Wistar rats were randomly assigned to one of three groups The control group received standard laboratory chow, and the groups with T2DM received a single dose of 45 mg/kg body weight of streptozotocin (STZ) after 3 weeks of pretreatment with a high-fat diet (HFD). Eight weeks after the diagnosis of T2DM, rats were divided into two groups: the T2DM model group and the T2DM + MSCs group. BM-MSCs were administered systemically at 2 × 106 cells/rat doses. A Significant amelioration in Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) and dyslipidemia was noted 2 weeks post-administration of MSCs. Administration of MSCs improved dyslipidemia, the altered cardiac injury biomarkers (p ≤ 0.0001), downregulated Janus kinase 2/signal transducer and activator of transcription 3(JAK2/STAT3)/inducible Nitric oxide synthase (iNOS) and iNOS/Apoptosis signaling pathways. This was associated with improved cardiac dysfunction (impaired left ventricular performance and decreased contractility index). Our results show that MSCs ameliorate cardiac dysfunction associated with diabetic cardiomyopathy by lowering dyslipidemia and insulin resistance, inhibiting oxidative stress, and inflammation, downregulating JAK2/STAT3/iNOS and iNOS/Apoptosis signaling pathways.

Inhibition of α4β1 Integrin Activity by Small Tellurium Compounds Regulates PD-L1 Expression and Enhances Antitumor Effects

Various cancer treatment approaches that inhibit the activity of the programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) axis, a key player in tumor immune evasion, have been developed. We show that the immunomodulatory small tellurium complexes AS101 (ammonium trichloro(dioxoethylene-o,o')tellurate) and SAS (octa-O-bis(R,R)-tartarate ditellurane) suppress PD-L1 expression in a variety of human and mouse malignant cells via the modulation of α4β1 very late antigen-4 (VLA-4) integrin activity. Consequently, the expression of pAkt and its downstream effector pNFκB are inhibited. Additionally, SAS promotes the death of mouse malignant cells by activated syngeneic splenocytes or CD8+ T cells, preventing the development of chemoresistance in malignant cells. Moreover, AS101 and SAS may increase, at least in part, chemosensitivity through inhibition of the VLA-4/IL-10/PD-L1 pathway. Additionally, AS101 or SAS treatment of B16/F10 melanoma-bearing mice decreased tumor cell PD-L1 expression, leading to increased CD8+ T-cell infiltration into the tumors and tumor shrinkage. Combination treatment with an αPD-1 antibody and either tellurium compound significantly increased the antitumor efficacy of immunotherapy. Overall, VLA-4 integrin signaling is critical for tumor immune evasion and is a potential target for cancer treatment. Finally, AS101 or SAS, biologically active tellurium compounds, can effectively enhance the therapeutic efficacy of αPD-1-based cancer immunotherapy.

Synthesis and screening for anticancer activity of two novel telluro-amino acids: 1,3-Tellurazolidine-4-carboxylic acid and tellurohomocystine

Tellurium (Te) containing amino acids and their derivatives have the potential to participate in biological processes, which are currently being studied extensively to understand the function of Te in biological and pharmacological activities. Here, we are reporting the synthesis of two novel Te-containing unnatural amino acids; 1,3-Tellurazolidine-4-carboxylic acid [Te{CH2CH(COOH)NHCH2}] 5, and 4,4'-(1,2-Ditellurdiyl)bis(2-aminobutanoic acid), i.e., tellurohomocystine [TeCH2CH2CH(NH2)COOH]2 7, synthesized from tellurocystine, and L-methionine as precursors, respectively. These telluro-amino acids were thoroughly characterized by multinuclear (1H, 13C, 125Te) NMR spectroscopy, high-resolution ESI-mass spectrometry (ESI-MS), and elemental analysis. The telluro-amino acids 5 and 7 demonstrated good biocompatibility when in vitro cytotoxicity was analyzed on two fibroblast cell lines L929 and NIH/3T3. The treatment of telluro-amino acids 1,3-Tellurazolidine-4-carboxylic acid 5 and tellurohomocystine 7 on breast cancer cell line MCF-7 showed anticancer activity with IC50 values of 7.29 ± 0.27 µg/mL and 25.36 ± 0.12 µg/mL, respectively. The cell cycle distribution studies also revealed arrest at the sub-G1 phase suggesting telluro-amino acids to be apoptotic.

Use of Microbial Consortia in Bioremediation of Metalloid Polluted Environments

Metalloids are released into the environment due to the erosion of the rocks or anthropogenic activities, causing problems for human health in different world regions. Meanwhile, microorganisms with different mechanisms to tolerate and detoxify metalloid contaminants have an essential role in reducing risks. In this review, we first define metalloids and bioremediation methods and examine the ecology and biodiversity of microorganisms in areas contaminated with these metalloids. Then we studied the genes and proteins involved in the tolerance, transport, uptake, and reduction of these metalloids. Most of these studies focused on a single metalloid and co-contamination of multiple pollutants were poorly discussed in the literature. Furthermore, microbial communication within consortia was rarely explored. Finally, we summarized the microbial relationships between microorganisms in consortia and biofilms to remove one or more contaminants. Therefore, this review article contains valuable information about microbial consortia and their mechanisms in the bioremediation of metalloids.

Synthesis, Mechanism Elucidation and Biological Insights of Tellurium(IV)-Containing Heterocycles

Inspired by the synthetic and biological potential of organotellurium substances, a series of five- and six-membered ring organotelluranes containing a Te-O bond were synthesized and characterized. Theoretical calculations elucidated the mechanism for the oxidation-cyclization processes involved in the formation of the heterocycles, consistent with chlorine transfer to hydroxy telluride, followed by a cyclization step with simultaneous formation of the new Te-O bond and deprotonation of the OH group. Moreover, theoretical calculations also indicated anti-diastereoisomers to be major products for two chirality center-containing compounds. Antileishmanial assays against Leishmania amazonensis promastigotes disclosed 1,2λ⁴ -oxatellurane LQ50 (IC₅₀ =4.1±1.0; SI=12), 1,2λ⁴ -oxatellurolane LQ04 (IC₅₀ =7.0±1.3; SI=7) and 1,2λ⁴ -benzoxatellurole LQ56 (IC₅₀ =5.7±0.3; SI=6) as more powerful and more selective compounds than the reference, being up to four times more active. A stability study supported by ¹²⁵ Te NMR analyses showed that these heterocycles do not suffer structural modifications in aqueous-organic media or at temperatures up to 65 °C.

The tellurium-based immunomodulator, AS101 ameliorates adjuvant-induced arthritis in rats

Despite undeniable improvement in the management of rheumatoid arthritis (RA), the discovery of more effective, less toxic and, ideally, less immune suppressive drugs are much needed. In the current study, we set to explore the potential anti-rheumatic activity of the non-toxic, tellurium-based immunomodulator, AS101 in an experimental animal model of RA. The effect of AS101 was assessed on adjuvant-induced arthritis (AIA) rats. Clinical signs of arthritis were assessed. Histopathological examination was used to assess inflammation, synovial changes and tissue lesions. Very late antigen-4 (VLA-4)+ cellular infiltration was detected using immunohistochemical staining. Enzyme-linked immunosorbent assay (ELISA) was used to measure circulating anti-cyclic citrullinated-peptide autoantibody (ACPA) and real-time polymerase chain reaction (PCR) was used to measure the in-vitro effect of AS101 on interleukin (IL)-6 and IL-1β expression in activated primary human fibroblasts. Prophylactic treatment with intraperitoneal AS101 reduced clinical arthritis scores in AIA rats (P < 0·01). AS101 abrogated the migration of active chronic inflammatory immune cells, particularly VLA-4+ cells, into joint cartilage and synovium, reduced the extent of joint damage and preserved joint architecture. Compared to phosphate-buffered saline (PBS)-treated AIA rats, histopathological inflammatory scores were significantly reduced (P < 0·05). Furthermore, AS101 resulted in a marked reduction of circulating ACPA in comparison to PBS-treated rats (P < 0·05). Importantly, AS101 significantly reduced mRNA levels of proinflammatory mediators such as IL-6 (P < 0·05) and IL-1β (P < 0·01) in activated primary human fibroblasts. Taken together, we report the first demonstration of the anti-rheumatic/inflammatory activity of AS101 in experimental RA model, thereby supporting an alternative early therapeutic intervention and identifying a promising agent for therapeutic intervention.

Tellurium: A new active element for innovative multifunctional bioactive glasses

Bioactive glasses have been widely investigated for their ability to release ions with therapeutic effect. In this paper, a silica based bioactive glass was doped with a low amount of tellurium dioxide (1 and 5 mol%) to confer antibacterial and antioxidant properties. The obtained glasses were characterized in terms of morphology, composition, structure, characteristic temperatures and in vitro bioactivity. Moreover, comprehensive analyses were carried out to estimate the cytocompatibility, the antibacterial and antioxidant properties of Te-doped glasses. The performed characterizations demonstrated that the Te insertion did not interfere with the amorphous nature of the glass, the substitution of SiO₂ with TeO₂ led to a slight decrease in T_g and a TeO₂ amount higher than 1 mol% can induce a change in the primary crystal field. In vitro bioactivity test demonstrated the Te-doped glass ability to induce the precipitation of hydroxyapatite. Finally, the biological characterization showed a strong antibacterial and antioxidant effects of Te-containing glasses in comparison with the control glass, demonstrating that Te is a promising element to enhance the biological response of biomaterials.

N-acetylcysteine modulates non-esterified fatty acid-induced pyroptosis and inflammation in granulosa cells

In the perinatal period of dairy cows, negative energy balance (NEB) is likely to occur, which increases the level of non-esterified fatty acids (NEFA) in the follicular fluid, hinders the proliferation of granulosa cells (GCs), and thus endangers the development of oocytes and the fecundity of dairy cows. We found that there were oxidative stress and inflammatory response in the serum of cows with perinatal ketosis. Whether the oxidative stress induced by NEFA is involved in the pyroptosis and inflammation of GCs remains unclear. After NEFA treatment, the expression of NLRP3 and caspase-1 and the release of inflammatory cytokines IL-1β were increased in a dose-dependent manner, indicating that NEFA may contribute to pyroptosis. Besides, NEFA stimulation induced oxidative stress, resulting in the phosphorylation of NF-κB, and increased the production of interleukin (IL)-6 and nitric oxide (NO), indicating that NEFA may induce inflammation in GCs. However, the NEFA-mediated effects were observably reversed when the GCs were pre-treated with antioxidant and radical scavenger, N-acetylcysteine (NAC). Taken together, our results reveal that NEFA can induce pyroptosis and inflammation through NLRP3 inflammasome and TLR4/NF-κB pathway, respectively, and NAC can alleviate these conditions.

Telluric acid ameliorates hepatic ischemia reperfusion-induced injury in rats: Involvement of TLR4, Nrf2, and PI3K/Akt signaling pathways

In past tellurium-based compounds had limited use, however, their therapeutic potential have been target of interest recently due to antioxidant and anti-inflammatory capabilities in experimental endotoxemia. Nevertheless, their potential hepatoprotective effect against ischemia reperfusion (IR) injury is still obscure. This study examined the possible hepatoprotective effect of telluric acid (TELL), one of tellurium-based compound, against the deteriorating effect hepatic IR injury in rats through directing toll like receptor-4 (TLR4) cascade, phosphoinositide 3-kinase(PI3K)/Akt axis, and nuclear erythroid-related factor-2 (Nrf-2) pathway as possible mechanisms contributed to TELL's effect. Indeed, male Wistar rats were randomized into 3 groups: sham-operated, control IR and TELL (50 µg/kg). TELL was administrated once daily for seven consecutive days prior to the IR induction. Pretreatment with TELL attenuated hepatic IR injury as manifested by hampered plasma aminotransaminases and lactate dehydrogenase activities. Also, TELL opposed IR induced elevation in tissue expression/activity of high-mobility group box protein-1 (HMGB1), TLR4, myeloid differentiation primary-response protein 88 (MyD88), phospho-nuclear factor-kappa B p65 (p-NF-κB p65), phospho-mitogen activated protein kinasep38 (p-MAPKp38) and tumor necrosis factor-alpha (TNF-α). Moreover, TELL reduced the elevated thiobarbituric acid reactive substances along with increased both Nrf-2 and endothelial nitric oxide synthase (eNOS) protein expression, beside replenishment of hepatic reduced glutathione. In addition, TELL induced obvious upregulation of p-PI3K and p-Akt protein expressions together with restoration of histopathological changes in IR injury. In conclusion, TELL purveyed conceivable novel hepatoprotective mechanisms and attenuated events associated with acute hepatic injury via inhibition of TLR4 downstream axis and activation of Nrf-2 and PI3K/Akt signaling cascades. Thus, TELL may provide a novel therapeutic potential for complications of hepatic IR injury.

AS101 ameliorates experimental autoimmune uveitis by regulating Th1 and Th17 responses and inducing Treg cells

AS101 is an organotellurium compound with multifaceted immunoregulatory properties that is remarkable for its lack of toxicity. We tested the therapeutic effect of AS101 in experimental autoimmune uveitis (EAU), a model for human autoimmune uveitis. Unexpectedly, treatment with AS101 elicited Treg generation in vivo in otherwise unmanipulated mice. Mice immunized for EAU with the retinal antigen IRBP and treated with AS101 developed attenuated disease, as did AS101-treated recipients of retina-specific T cells activated in vitro. In both settings, eye-infiltrating effector T cells were decreased, whereas regulatory T (Treg) cells in the spleen were increased. Mechanistic studies in vitro revealed that AS101 restricted polarization of retina-specific T cells towards Th1 or Th17 lineage by repressing activation of their respective lineage-specific transcription factors and downstream signals. Retina-specific T cells polarized in vitro towards Th1 or Th17 in the presence of AS101 had impaired ability to induce EAU in naïve recipients. Finally, AS101 promoted differentiation of retina-specific T cells to Tregs in vitro independently of TGF-β. We conclude that AS101 modulates autoimmune T cells by inhibiting acquisition and expression of effector function and by promoting Treg generation, and suggest that AS101 could be useful as a therapeutic approach for autoimmune uveitis.

Syntheses, characterization, DNA/BSA binding, and in vitro cytostatic activity of fluorobenzenetelluronic triorganotin(iv) esters

A new series of fluorobenzenetelluronic triorganotin(iv) esters (1–6) have been synthesized by the reaction of deprotonated fluorobenzenetelluronic acid ligands and the corresponding R₃SnCl (R = Me, Ph).

Telluric Acid Ameliorates Endotoxemic Kidney Injury in Mice: Involvement of TLR4, Nrf2, and PI3K/Akt Signaling Pathways

Being one of the most abundant trace elements in the human body, the therapeutic potential of tellurium-based compounds has been a target of interest. Recent reports denoted their redox-modulating and anti-inflammatory activities in experimental endotoxemia. However, their potential nephroprotective effect against endotoxemic kidney injury is yet to be elucidated. This study investigated the possible renoprotective effect of telluric acid (TEL) against lipopolysaccharide (LPS)-induced acute kidney injury (AKI) in mice, targeting toll-like receptor 4 (TLR4), phosphoinositide 3-kinase (PI3K)/Akt, and nuclear factor-erythroid 2-related factor-2 (Nrf2) pathways as possible mechanistic contributors to TEL's effect. AKI was induced by LPS (2 mg/kg). TEL (60 μg/kg; i.p.) was administered once daily for seven consecutive days before LPS injection. Pretreatment with TEL alleviated LPS-induced AKI as evidenced by the hampered serum levels of creatinine and cystatin C. TEL also opposed LPS-induced elevation in renal kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, nuclear factor-kappa B p65, interleukin-1β, and thiobarbituric acid-reactive substance contents. This was accompanied by a replenishment of renal glutathione, transcriptional upregulation of Nrf2, enhancement of heme oxygenase-1 activity, and a marked upregulation of phospho-PI3K and phospho-Akt protein expressions. Histopathological findings corroborated with the amendment of biochemical parameters. In view of these findings, we may conclude that TEL pretreatment purveyed novel nephroprotective effects against endotoxemic kidney injury, which might be partly attributed to the modulation of TLR4, PI3K/Akt, and Nrf2 signaling pathways and may hence provide a valuable asset for the management of endotoxemic renal complications.

Investigation of Chemical Stability of Dihalogenated Organotelluranes in Organic-Aqueous Media: The Protagonism of Water

The biological activity of tellurium compounds is closely related to the tellurium oxidation state or some of their structural features. Hypervalent dihalogenated organotelluranes 1-[butyl(dichloro)-λ⁴-tellanyl]-2-(methoxymethyl)benzene (1a) and 1-[butyl(dibromide)-λ⁴-tellanyl]-2-(methoxymethyl)benzene (1b) have been described as inhibitors of proteases (cysteine and threonine) and tyrosine phosphatases. However, poor attention has been given to their physicochemical properties. Here, a detailed investigation of the stability in water of these organotelluranes is reported using ¹²⁵Te NMR analysis. Dihalogenated organotelluranes 1a and 1b were both stable in DMSO- d₆ (from 25 to 75 °C), demonstrating their thermal stability. However, the addition of a phosphate buffer solution (pH 2-8) to 1a or 1b resulted in an immediate conversion to a new Te species, assumed to be the corresponding telluroxide. Similar behavior was observed in pure water, demonstrating the low chemical stability of these dihalogenated species in the presence of water. These results allow concluding that previous biological activity reported for dihalogenated organotelluranes 1a and 1b could be attributed to the corresponding derivatives from the reaction with water. In the same way as for AS-101, we demonstrated that organotelluranes 1a and 1b are not stable in aqueous solution. It suggests a proactive role of these organotelluranes in previously reported biological activity.

Redox control of cancer cell destruction

Redox regulation has been proposed to control various aspects of carcinogenesis, cancer cell growth, metabolism, migration, invasion, metastasis and cancer vascularization. As cancer has many faces, the role of redox control in different cancers and in the numerous cancer-related processes often point in different directions. In this review, we focus on the redox control mechanisms of tumor cell destruction. The review covers the tumor-intrinsic role of oxidants derived from the reduction of oxygen and nitrogen in the control of tumor cell proliferation as well as the roles of oxidants and antioxidant systems in cancer cell death caused by traditional anticancer weapons (chemotherapeutic agents, radiotherapy, photodynamic therapy). Emphasis is also put on the role of oxidants and redox status in the outcome following interactions between cancer cells, cytotoxic lymphocytes and tumor infiltrating macrophages.

The Natural Carotenoid Crocetin and the Synthetic Tellurium Compound AS101 Protect the Ovary against Cyclophosphamide by Modulating SIRT1 and Mitochondrial Markers

Cancer therapies are associated with increased infertility risk due to accelerated reproductive aging. Oxidative stress (OS) is a potential mechanism behind ovarian toxicity by cyclophosphamide (CPM), the most ovotoxic anticancer drug. An important sensor of OS is SIRT1, a NAD⁺-dependent deacetylase which regulates cellular defence and cell fate. This study investigated whether the natural carotenoid crocetin and the synthetic compound AS101 protect the ovary against CPM by modulating SIRT1 and mitochondrial markers. We found that the number of primordial follicles of female CD1 mice receiving crocetin plus CPM increased when compared with CPM alone and similar to AS101, whose protective effects are known. SIRT1 increased in CPM mouse ovaries revealing the occurrence of OS. Similarly, mitochondrial SIRT3 rose, whilst SOD2 and the mitochondrial biogenesis activator PGC1-α decreased, suggesting the occurrence of mitochondrial damage. Crocetin and AS101 administration prevented SIRT1 burst suggesting that preservation of redox balance can help the ovary to counteract ovarian damage by CPM. Decreased SIRT3 and increased SOD2 and PGC1-α in mice receiving crocetin or AS101 prior to CPM provide evidence for mitochondrial protection. Present results improve the knowledge of ovarian damage by CPM and may help to develop interventions for preserving fertility in cancer patients.

Crystallographic and docking (Cathepsins B, K, L and S) studies on bioactive halotelluroxetanes

The molecular structures of the halotelluroxetanes p-MeOC6H4Te(X)[C(=C(H)X′)C(CH2)nO], X=X′=Cl and n=6 (1) and X=Cl, X′=Br and n=5 (4), show similar binuclear aggregates sustained by {· · ·Te–O}2 cores comprising covalent Te–O and secondary Te· · ·O interactions. The resulting C2ClO2(lone-pair) sets define pseudo-octahedral geometries. In each structure, C–X· · ·π(arene) interactions lead to supramolecular layers. Literature studies have shown these and related compounds (i.e. 2: X=X′=Cl and n=5; 3: X=X′=Br and n=5) to inhibit Cathepsins B, K, L and S to varying extents. Molecular docking calculations have been conducted on ligands (i.e. cations derived by removal of the tellurium-bound X atoms) 1′–3′ (note 3′=4′) enabling correlations between affinity for sub-sites and inhibition. The common feature of all docked complexes was the formation of a Te–S covalent bond with cysteine residues, the relative stability of the ligands with an E-configuration and the formation of a C–O· · ·π interaction with the phenyl ring; for 1′ the Te–S covalent bond was weak, a result correlating with its low inhibition profile. At the next level differences are apparent, especially with respect to the interactions formed by the organic-ligand-bound halides. While these atoms do not form specific interactions in Cathepsins B and K, in Cathepsin L, these halides are involved in C–O· · ·X halogen bonds.

1-Butyl-1-chloro-3-methyl-3H-2,1λ4-benzoxa-tellurole: crystal structure and Hirshfeld analysis

Two independent mol-ecules comprise the asymmetric unit in the title benzoxatellurole compound, C12H17ClOTe. The mol-ecules, with the same chirality at the methine C atom, are connected into a loosely associated dimer by Te⋯O inter-actions, leading to a {⋯Te-O}2 core. The resultant C2ClO2 donor set approximates a square pyramid with the lone pair of electrons projected to occupy a position trans to the n-butyl substituent. Inter-estingly, the TeIV atoms exhibit opposite chirality. The major difference between the independent mol-ecules relates to the conformation of the five-membered chelate rings, which is an envelope with the O atom being the flap, in one mol-ecule and is twisted about the O-C(methine) bond in the other. No directional inter-molecular inter-actions are noted in the mol-ecular packing beyond the aforementioned Te⋯O secondary bonding. The analysis of the Hirshfeld surface reveals the dominance of H⋯H contacts, i.e. contributing about 70% to the overall surface, and clearly differentiates the immediate crystalline environments of the two independent mol-ecules in terms of both H⋯H and H⋯Cl/Cl⋯H contacts.

Anti-lipoapoptotic effects of Alisma orientalis extract on non-esterified fatty acid-induced HepG2 cells

BACKGROUND

Liver steatosis was caused by lipid accumulation in the liver. Alisma orientale (AO) is recognized as a promising candidate with therapeutic efficacy for the treatment of nonalcoholic fatty liver disease (NAFLD). HepG2 hepatocyte cell line is commonly used for liver disease cell model.

METHOD

The HepG2 cells were cultured with the NEFAs mixture (oleic and palmitic acids, 2:1 ratio) for 24 h to induce hepatic steatosis. Then different doses of Alisma orientale extract (AOE) was treated to HepG2 for 24 h. Incubated cells were used for further experiments.

RESULTS

The AOE showed inhibitory effects on lipid accumulation in the Oil Red O staining and Nile red staining tests with no cytotoxicity at a concentration of 300 μg/mL. Fatty acid synthase (FASN) and acetyl-CoA carboxylase 1 (ACC1) mRNA and protein expression level were down-regulated after AOE treatment. Bcl-2 associated X protein (Bax) and c-Jun N-terminal kinase (JNK) mRNA expression level were decreased as well as p-JNK (activated form of JNK), Bax, cleaved caspase-9, caspase-3 protein expression level. Anti-apopototic B-cell lymphoma 2 (Bcl-2) protein level increased after AOE treatment. In addition, inflammatory protein expression including p-p65, p65, COX-2 and iNOS were inhibited by AOE treatment.

CONCLUSION

The results suggest that AOE has anti-steatosis effects that involve lipogenesis, anti-lipoapoptosis, and anti-inflammation in the NEFA-induced NAFLD pathological cell model.

The small tellurium-based compound SAS suppresses inflammation in human retinal pigment epithelium

PURPOSE

Pathological angiogenesis and chronic inflammation greatly contribute to the development of choroidal neovascularization (CNV) in chorioretinal diseases involving abnormal contact between retinal pigment epithelial (RPE) and endothelial cells (ECs), associated with Bruch's membrane rupture. We explored the ability of the small organotellurium compound octa-O-bis-(R,R)-tartarate ditellurane (SAS) to mitigate inflammatory processes in human RPE cells.

METHODS

Cell adhesion assays and analyses of gene and protein expression were used to examine the effect of SAS on ARPE-19 cells or primary human RPE cells that were grown alone or in an RPE-EC co-culture.

RESULTS

Adhesion assays showed that SAS inhibited αv integrins expressed on RPE cells. Co-cultures of RPE cells with ECs significantly reduced the gene expression of PEDF, as compared to RPE cells cultured alone. Both SAS and the anti-αvβ3 antibody LM609 significantly enhanced the production of PEDF at both mRNA and protein levels in RPE cells. RPE cells co-cultured with EC exhibited increased gene expression of CXCL5, COX1, MMP2, IGF1, and IL8, all of which are involved in both angiogenesis and inflammation. The enhanced expression of these genes was greatly suppressed by SAS, but interestingly, remained unaffected by LM609. Zymography assay showed that SAS reduced the level of MMP-2 activity in RPE cells. We also found that SAS significantly suppressed IL-1β-induced IL-6 expression and secretion from RPE cells by reducing the protein levels of phospho-IkappaBalpha (pIκBα).

CONCLUSIONS

Our results suggest that SAS is a promising anti-inflammatory agent in RPE cells, and may be an effective therapeutic approach for controlling chorioretinal diseases.

77Se and 125Te NMR spectroscopy on a selectivity study of organochalcogenanes with l-amino acids

Organochalcogenanes exhibited a remarkably high selectivity for l-cysteine which was monitored by ⁷⁷Se and ¹²⁵Te NMR spectroscopy.

The effect of the novel tellurium compound AS101 on autoimmune diseases

Tellurium is a rare element, which has been regarded as a non-essential trace element despite its relative abundance in the human body. The chemistry of tellurium supports a plethora of activities, but its biochemistry is not clearly established to date. The small tellurium(IV) compound, ammonium trichloro (dioxoethylene-o,o')tellurate (AS101) developed and initially investigated by us, is currently being evaluated in Phase II clinical trials in psoriasis patients. AS101 is the first tellurium compound to be tested for clinical efficacy. This compound is a potent immunomodulator both in vitro and in vivo with a variety of potential therapeutic applications. The present review will focus on the immunomodulatory properties of AS101, and specifically, its effects in mitigating autoimmune diseases. AS101 has several activities that act on the immune system, including: 1) its ability to reduce IL-17 levels and to inhibit the function of Th17 cells; 2) its specific unique redox-modulating activities enabling the inhibition of specific leukocyte integrins such as α4β1 and α4β7, that are pivotal for diapedesis of macrophages and CD4(+) T inflammatory/auto-reactive cells into the autoimmune tissues; and 3) its ability to enhance the activity of regulatory T cells (Treg). These activities coupled with its excellent safety profile suggest that AS101 may be a promising candidate for the management of autoimmune diseases.

The immunomodulator AS101 suppresses production of inflammatory cytokines and ameliorates the pathogenesis of experimental autoimmune encephalomyelitis

We reported that AS101 (organotellurium compound, trichloro(dioxoethylene-O,O') tellurate) inhibited the differentiation of Th17 cells and reduced the production of IL-17 and GM-CSF. In addition, AS101 promoted the production of IL-2 in activated T cells. Flow cytometric analysis showed that AS101 inhibited Th17 cell proliferation. AS101 blocked the activation of transcriptional factor NFAT, Stat3, and RORγt, and increased activation of Erk1/2, suggesting a mechanism of action of AS101. We further demonstrated that AS101 was effective in amelioration of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Finally, by real-time PCR analysis we showed that AS101 reduces the IL-17, IFN-γ, GM-CSF, and IL-6 mRNA expression in inflammatory cells of spinal cords. Additionally, flow cytometry analysis also indicated that the CD4+ T cells and IL-17 and GM-CSF-producing cells were reduced in the spinal cords of AS101 treated mice compared to those treated with PBS.

Effects of plant-based Korean food extracts on lipopolysaccharide-stimulated production of inflammatory mediators in vitro

BACKGROUND/OBJECTIVES

The traditional Korean diet is plant-based and rich in antioxidants. Previous studies have investigated the potential health benefits of individual nutrients of Korean foods. However, the cumulative effects of a Korean diet on inflammation remain poorly understood. Therefore, the aim of this study was to investigate the anti-inflammatory effects of a plant-based Korean diet.

MATERIALS/METHODS

Using data from the Fifth Korean National Health and Nutrition Examination Survey, 75 individual plant food items were selected which represent over 1% of the total diet intake of the Korean diet. These items were classified into ten different food groups, and the vegetable (Veg) and fruit (Fruit) groups were studied based on their high antioxidant capacity. For comparison, a mixture of all ten groups (Mix) was prepared. To produce a model of inflammation with which to test these Veg, Fruit, and Mix plant-based Korean food extracts (PKE), RAW264.7 macrophages were treated with lipopolysaccharide (LPS).

RESULTS

Levels of nitric oxide (NO) and prostaglandin E2 (PGE2), as well as protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were found to be lower following PKE treatment. Furthermore, PKE treatment was found to suppress tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) via the nuclear transcription factor kappa-B (NF-κB) signaling pathway. Overall, the Mix group exhibited the greatest anti-inflammatory effects compared with Veg and Fruit PKE group.

CONCLUSIONS

Inhibition of LPS-induced pro-inflammatory mediators by the PKE tested was found to involve an inhibition of NF-kB activation. Moreover, PKE tested have the potential to ameliorate various inflammation-related diseases by limiting the excessive production of pro-inflammatory mediators.

Multifunctional activity of a small tellurium redox immunomodulator compound, AS101, on dextran sodium sulfate-induced murine colitis

Inflammatory bowel diseases (IBDs) are a group of idiopathic, chronic immune-mediated diseases characterized by an aberrant immune response, including imbalances of inflammatory cytokine production and activated innate and adaptive immunity. Selective blockade of leukocyte migration into the gut is a promising strategy for the treatment of IBD. This study explored the effect of the immunomodulating tellurium compound ammonium trichloro (dioxoethylene-o,o') tellurate (AS101) on dextran sodium sulfate (DSS)-induced murine colitis. Both oral and intraperitoneal administration of AS101 significantly reduced clinical manifestations of IBD. Colonic inflammatory cytokine levels (IL-17 and IL-1β) were significantly down-regulated by AS101 treatment, whereas IFN-γ was not affected. Neutrophil and α4β7(+) macrophage migration into the tissue was inhibited by AS101 treatment. Adhesion of mesenteric lymph node cells to mucosal addressin cell adhesion molecule (MAdCAM-1), the ligand for α4β7 integrin, was blocked by AS101 treatment both in vitro and in vivo. DSS-induced destruction of colonic epithelial barrier/integrity was prevented by AS101, via up-regulation of colonic glial-derived neurotrophic factor, which was found previously to regulate the intestinal epithelial barrier through activation of the PI3K/AKT pathway. Indeed, the up-regulation of glial-derived neurotrophic factor by AS101 was associated with increased levels of colonic pAKT and BCL-2 and decreased levels of BAX. Furthermore, AS101 treatment reduced colonic permeability to Evans blue and decreased colonic TUNEL(+) cells. Our data revealed multifunctional activities of AS101 in the DSS-induced colitis model via anti-inflammatory and anti-apoptotic properties. We suggest that treatment with the small, nontoxic molecule AS101 may be an effective early therapeutic approach for controlling human IBD.

Novel microwave-assisted synthesis of the immunomodulator organotellurium compound ammonium trichloro(dioxoethylene-O,O')tellurate (AS101)

Ammonium trichloro[1,2-ethanediolato-O,O′]-tellurate (AS101) is the most important synthetic Te compound from the standpoint of its biological activity. It is a potent immunomodulator with a variety of potential therapeutic applications and antitumoral action in several preclinical and clinical studies. An experimental design has been used to develop and optimize a novel microwave-assisted synthesis (MAOS) of the AS101. In comparison to the results observed in the literature, refluxing Te(IV) chloride and ethylene glycol in acetonitrile (Method A), or by refluxing Te(IV) chloride and ammonium chloride in ethylene glycol (Method B), it was found that the developed methods in the present work are an effective alternative, because although performance slightly decreases compared to conventional procedures (75% vs. 79% by Method A, and 45% vs. 51% by Method B), reaction times decreased from 4 h to 30 min and from 4 h to 10 min, by Methods A and B respectively. MAOS is proving to be of value in the rapid synthesis of compounds with new and improved biological activities, specially based on the benefit of its shorter reaction times.

Tellurium compound AS101 ameliorates experimental autoimmune encephalomyelitis by VLA-4 inhibition and suppression of monocyte and T cell infiltration into the CNS

Multiple sclerosis (MS) is an inflammatory autoimmune disease of the central nervous system (CNS) involving demyelinating and neurodegenerative processes. Several of the major pathological CNS alterations and behavioral deficits of MS are recapitulated in the experimental autoimmune encephalitis (EAE) mouse model in which the disease process is induced by administration of myelin peptides. Development of EAE requires infiltration of inflammatory cytokine-generating monocytes and macrophages, and auto-reactive T cells, into the CNS. Very late antigen-4 (VLA-4, α4β1) is an integrin molecule that plays a role in inflammatory responses by facilitating the migration of leukocytes across the blood-brain barrier during inflammatory disease, and antibodies against VLA-4 exhibit therapeutic efficacy in mouse and monkey MS models. Here, we report that the tellurium compound AS101 (ammonium trichloro (dioxoethylene-o,o') tellurate) ameliorates EAE by inhibiting monocyte and T cell infiltration into the CNS. CD49d is an alpha subunit of the VLA-4 (α4β1) integrin. During the peak stage of EAE, AS101 treatment effectively ameliorated the disease process by reducing the number of CD49d(+) inflammatory monocyte/macrophage cells in the spinal cord. AS101 treatment markedly reduced the pro-inflammatory cytokine levels, while increasing anti-inflammatory cytokine levels. In contrast, AS101 treatment did not affect the peripheral populations of CD11b(+) monocytes and macrophages. AS101 treatment reduced the infiltration of CD4(+) and CD49(+)/VLA4 T cells. In addition, treatment of T cells from MS patients with AS101 resulted in apoptosis, while such treatment did not affect T cells from healthy donors. These results suggest that AS101 reduces accumulation of leukocytes in the CNS by inhibiting the activity of the VLA-4 integrin and provide a rationale for the potential use of Tellurium IV compounds for the treatment of MS.

Evaluating the anti-inflammatory potential of Tectaria cicutaria L. rhizome extract in vitro as well as in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Tectaria cicutaria has been used in the folklore system of Indian traditional medicine (Ayurveda) for the treatment of various disorders such as rheumatic pain, chest complaints, burns, sprain, poisonous bites, tonsilitis, toothache, gum complaints, cuts and wounds. The present work has for the first time tried to elucidate the anti-inflammatory potential of aqueous extract of Tectaria cicutaria rhizome (TCRaq) in vitro as well as in vivo.

MATERIALS AND METHODS

Anti-inflammatory potential of TCRaq was analyzed in vivo in carrageenan induced rat paw edema model. Serum antioxidant status in TCRaq-treated as well as untreated control rodents was measured by oxygen radical absorbance capacity (ORAC) assay. In vitro experiments for analyzing the anti-inflammatory potential of TCRaq were performed on murine macrophage cell line, RAW 264.7. Analysis of nitric oxide release in RAW 264.7 cells was done by Griess reaction. RT-PCR and western blotting experiment was performed to analyze the expression of iNOS. Expression of COX-2 and NFκB proteins was evaluated by western blotting.

RESULTS

TCRaq significantly reduced the paw volume in Sprague-Dawley rats at a dose of 200mg/kg body weight, which was comparable with the standard diclofenac treatment. The rats treated with TCRaq showed a significant increase in the serum antioxidant levels compared to the untreated control animals. TCRaq was able to reduce the nitric oxide (NO) levels in RAW 264.7 cells that had been stimulated with lipopolysaccharide (LPS). This was accompanied by a corresponding decrease in iNOS expression at mRNA and protein level. Interestingly, TCRaq was found to decrease the expression of COX-2 as well as the nuclear translocation of NFκB in RAW 264.7 cells.

CONCLUSION

Our study signifies the anti-inflammatory potential of Tectaria cicutaria and scientifically validates its traditional use in inflammatory conditions.

Anti-inflammatory effects of prosapogenin III from the dried roots of Liriope platyphylla in LPS-stimulated RAW264.7 cells

Liriope platyphylla has been reported to possess various biological activities, including anti-asthma, anti-inflammation, anti-diabetes, and neuriotogenic properties. In this study, we evaluated the effects of prosapogenin III isolated from the roots of L. platyphylla (Liriopis Tuber) on inflammatory responses in lipopolysaccharide (LPS) stimulated RAW264.7 mouse macrophages. We investigated LPS-induced production/expression of inflammatory mediators such as nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxigenase-2 (COX-2), and proinflammatory cytokines, including interleukin-1β (IL-1β) and interleukin (IL)-6 in RAW264.7 cells. We also performed Western blot analysis for determination of the phosphorylation of mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK) 1/2, p38, and c-Jun N-terminal kinase (JNK), and nuclear translocation of nuclear factor-κB (NF-κB) in LPS-stimulated cells. Treatment with prosapogenin III resulted in significant inhibition of NO production in LPS-stimulated Raw264.7 cells through suppression of iNOS expression. Treatment with prosapogenin III resulted in a significant decrease in expressions of COX-2, IL-1β, and IL-6 through down-regulation of their mRNA or protein in LPS-stimulated cells. In addition, treatment with prosapogenin III resulted in potently inhibited phosphorylation of three MAPKs, including ERK1/2, p38, and JNK in LPS-stimulated cells. Treatment with prosapogenin III also resulted in suppression of the nuclear translocation of NF-κB in LPS-stimulated cells. These results indicate that prosapogenin III of Liriopis Tuber has anti-inflammatory effects in activated macrophages through inhibition of production of inflammatory mediators by blockade of the MAPK/NF-κB pathway.

Propolis and its constituent caffeic acid suppress LPS-stimulated pro-inflammatory response by blocking NF-κB and MAPK activation in macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Propolis is a bee product with numerous biological and pharmacological properties, such as immunomodulatory and anti-inflammatory activities. It has been used in folk medicine as a healthy drink and in food to improve health and prevent inflammatory diseases. However, little is known about its mechanism of action. Thus, the goal of this study was to verify the antioxidant activity and to explore the anti-inflammatory properties of propolis by addressing its intracellular mechanism of action. Caffeic acid was investigated as a possible compound responsible for propolis action.

MATERIALS AND METHODS

The antioxidant properties of propolis and caffeic acid were evaluated by using the 2,2-Diphenyl-1-picrylhydrazyl free radical (DPPH) scavenging method. To analyze the anti-inflammatory activity, Raw 264.7 macrophages were treated with different concentrations of propolis or caffeic acid, and nitric oxide (NO) production, a strong pro-inflammatory mediator, was evaluated by the Griess reaction. The concentrations of propolis and caffeic acid that inhibited NO production were evaluated on intracellular signaling pathways triggered during inflammation, namely p38 mitogen-activated protein kinase (MAPK), c-jun NH2-terminal kinase (JNK1/2), the transcription nuclear factor (NF)-κB and extracellular signal-regulated kinase (ERK1/2), through Western blot using specific antibodies. A possible effect of propolis on the cytotoxicity of hepatocytes was also evaluated, since this product can be used in human diets.

RESULTS

Caffeic acid showed a higher antioxidant activity than propolis extract. Propolis and caffeic acid inhibited NO production in macrophages, at concentrations without cytotoxicity. Furthermore, both propolis and caffeic acid suppressed LPS-induced signaling pathways, namely p38 MAPK, JNK1/2 and NF-κB. ERK1/2 was not affected by propolis extract and caffeic acid. In addition, propolis and caffeic acid did not induce hepatotoxicity at concentrations with strong anti-inflammatory potential.

CONCLUSIONS

Propolis exerted an antioxidant and anti-inflammatory action and caffeic acid may be involved in its inhibitory effects on NO production and intracellular signaling cascades, suggesting its use as a natural source of safe anti-inflammatory drugs.

Metalloid compounds as drugs

The six elements commonly known as metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Metalloid containing compounds have been used as antiprotozoal drugs. Boron-based drugs, the benzoxaboroles have been exploited as potential treatments for neglected tropical diseases. Arsenic has been used as a medicinal agent and arsphenamine was the main drug used to treat syphilis. Arsenic trioxide has been approved for the treatment of acute promyelocytic leukemia. Pentavalent antimonials have been the recommended drug for visceral leishmaniasis and cutaneous leishmaniasis. Tellurium (IV) compounds may have important roles in thiol redox biological activity in the human body, and ammonium trichloro (dioxoethylene-O, O'-)tellurate (AS101) may be a promising agent for the treatment of Parkinson's disease. Organosilicon compounds have been shown to be effective in vitro multidrug-resistance reverting agents.

The tellurium redox immunomodulating compound AS101 inhibits IL-1β-activated inflammation in the human retinal pigment epithelium

PURPOSE

AS101 is a non-toxic organotellurium-IV compound with demonstrated immunomodulating activity in vitro and in vivo. Inflammatory responses are attributed to the pathophysiology of numerous ocular diseases. In this study, we wished to elucidate whether AS101 could mitigate pro-inflammatory activity in human retinal pigment epithelial (RPE) cells, which are heavily involved in ocular immune responses, induced by pro-inflammatory IL-β activity.

METHODS

Primary and transformed RPE cells treated with varying concentrations of AS101 were used in this study. Real-time PCR and ELISA assays were used to detect cytokine/chemokine mRNA expression and protein production. Western blot was used to detect changes in the NFκB pathway. Cell viability and proliferation were detected using a Vi-Cell XR cell counter. To measure the cytoprotective capacity of AS101, cell numbers were compared between cells treated with IL-1β or lipopolysaccharide (LPS) and cells treated with IL-1β or LPS in the presence of AS101.

RESULTS

AS101 inhibited IL-1β-induced mRNA expression and protein production of IL-6 and IL-8 in RPE cells. The viability of RPE cells treated with IL-1β and LPS was unaffected. AS101 slightly inhibited RPE cell growth in the presence of higher levels of IL-1β. Also, AS101 downregulated the IL-1β activity by inhibiting the phosphorylation of p65, an NFκB subunit.

CONCLUSIONS

The results demonstrate that AS101 reduces IL-1β-induced inflammatory responses in the RPE. In previous studies, AS101 exhibited therapeutic effects in various disease models and was a safe profile in clinical trials. These results suggest that AS101 may have potent anti-inflammatory potential in the eye and confer the downregulation of RPE inflammatory responses in a pathological environment.

Beta-mecaptoethanol suppresses inflammation and induces adipogenic differentiation in 3T3-F442A murine preadipocytes

Preadipocytes are present in adipose tissues throughout adult life that can proliferate and differentiate into mature adipocytes in response to environmental cues. Abnormal increase in adipocyte number or size leads to fat tissue expansion. However, it is now recognized that adipocyte hypertrophy is a greater risk factor for metabolic syndrome whereas fat tissue that continues to produce newer and smaller fat cells through preadipocyte differentiation is “metabolically healthy”. Because adipocyte hypertrophy is often associated with increased oxidant stress and low grade inflammation, both are linked to disturbed cellular redox, we tested how preadipocyte differentiation may be regulated by beta-mercaptoethanol (BME), a pharmacological redox regulator and radical scavenger, using murine 3T3-F442A preadipocytes as the cell model. Effects of BME on adipogenesis were measured by microphotography, real-time PCR, and Western analysis. Our data demonstrated that preadipocyte differentiation could be regulated by extracellular BME. At an optimal concentration, BME enhanced expression of adipogenic gene markers and lipid accumulation. This effect was associated with BME-mediated down-regulation of inflammatory cytokine expression during early differentiation. BME also attenuated TNFalpha-induced activation of NFkappaB in differentiating preadipocytes and partially restored TNFalpha-mediated suppression on adipogenesis. Using a non-adipogenic HEK293 cell line transfected with luciferase reporter genes, we demonstrated that BME reduced basal and TNFalpha-induced NFkappaB activity and increased basal and ciglitazone-induced PPARgamma activity; both may contribute to the pro-adipogenic effect of BME in differentiating F442A preadipocytes.

The tetramethoxyflavone zapotin selectively activates protein kinase C epsilon, leading to its down-modulation accompanied by Bcl-2, c-Jun and c-Fos decrease

Zapotin, a tetramethoxyflavone, is a natural compound with a wide spectrum of activities in neoplastic cells. Protein kinase C epsilon (PKCε) has been shown to be oncogenic, with the ability to increase cell migration, invasion and survival of tumor cells. Here we report that zapotin inhibits cell proliferation. In wild-type HeLa cells with basal endogenous expression of PKCε, the IC(50) was found to be 17.9 ± 1.6 μM. In HeLa cells overexpressing doxycycline-inducible constitutively active PKCε (HeLaPKCεA/E), the IC(50) was 7.6 ± 1.3 μM, suggesting that PKCε enhances the anti-proliferative effect of zapotin. Moreover, we found that zapotin selectively activated PKCε in comparison with other PKC family members, but attenuated doxycycline-induced PKCε expression. As a result of zapotin treatment for 6, 12 and 24h, the doxycycline-induced levels of the two differently phosphorylated PKCε forms (87 kDa and 95 kDa) were decreased. Migration assays revealed that increasing concentrations of zapotin (from 3.5 to 15 μM) decreased migration of HeLaPKCεA/E cells. Furthermore, zapotin significantly increased the fraction of apoptotic cells in doxycycline-induced (HeLaPKCεA/E) cells after 24h and decreased the levels of Bcl-2, c-Jun, c-Fos. This was accompanied by a degradation of PARP-1. In summary, activation of PKCε and down-modulation of the induced PKCε level by zapotin were associated with decreased migration and increased apoptosis. These observations are consistent with the previously reported chemopreventive and chemotherapeutic action of zapotin.

Thioredoxin interacting protein is a novel mediator of retinal inflammation and neurotoxicity

BACKGROUND AND PURPOSE

Up-regulation of thioredoxin interacting protein (TXNIP), an endogenous inhibitor of thioredoxin (Trx), compromises cellular antioxidant and anti-apoptotic defences and stimulates pro-inflammatory cytokines expression, implying a role for TXNIP in apoptosis. Here we have examined the causal role of TXNIP expression in mediating retinal neurotoxicity and assessed the neuroprotective actions of verapamil, a calcium channel blocker and an inhibitor of TXNIP expression.

EXPERIMENTAL APPROACH

Retinal neurotoxicity was induced by intravitreal injection of NMDA in Sprague-Dawley rats, which received verapamil (10 mg·kg(-1), p.o.) or vehicle. Neurotoxicity was examined by terminal dUTP nick-end labelling assay and ganglion cell count. Expression of TXNIP, apoptosis signal-regulating kinase 1 (ASK-1), NF-κB, p38 MAPK, JNK, cleaved poly-ADP-ribose polymerase (PARP), caspase-3, nitrotyrosine and 4-hydroxy-nonenal were examined by Western and slot-blot analysis. Release of TNF-α and IL-1β was examined by elisa.

KEY RESULTS

NMDA injection enhanced TXNIP expression, decreased Trx activity, causing increased oxidative stress, glial activation and release of TNF-α and IL-1β. Enhanced TXNIP expression disrupted Trx/ASK-1 inhibitory complex leading to release of ASK-1 and activation of the pro-apoptotic p38 MAPK/JNK pathway, as indicated by cleaved PARP and caspase-3 expression. Treatment with verapamil blocked these effects.

CONCLUSION AND IMPLICATIONS

Elevated TXNIP expression contributed to retinal neurotoxicity by three different mechanisms, inducing release of inflammatory mediators such as TNF-α and IL-1β, altering antioxidant status and disrupting the Trx-ASK-1 inhibitory complex leading to activation of the p38 MAPK/JNK apoptotic pathway. Targeting TXNIP expression is a potential therapeutic target for retinal neurodegenerative disease.

The phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 modulates cytokine expression in macrophages via p50 nuclear factor κB inhibition, in a PI3K-independent mechanism

The Phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002 (LY2), has been previously reported to inhibit nuclear factor κB (NFκB) activity, in a PI3K-independent mechanism. The goals of the current research were to determine the specificity of LY2 regarding NFκB subunits, and to identify relevant modulation of cytokine expression in LPS-stimulated macrophages. We found that LY2 specifically diminished the level of p50, but not p65, NFκB in the nucleus of LPS-stimulated mouse RAW264.7 macrophages and human THP-1 monocytes. This activity of LY2 was mimicked by its PI3K-inert analog LY303511 (LY3), but not by another PI3K inhibitor - wortmannin. We further show that LY2 inhibited LPS-induced IL-10 expression by RAW264.7 macrophages, in a PI3K-independent mechanism. Moreover, using a deletion mutant of an IL-10 promoter reporter gene we demonstrate that the activity of the NFκB enhancer site at the IL-10 promoter is regulated by LY2 in a PI3K-independent manner. Finally, both LY2 and LY3 elevated TNFα production in the LPS tolerant state which is regulated by p50 NFκB homodimers, but not before tolerance development. The effects of LY2 and LY3 on p50 translocation and on cytokine production in LPS-stimulated macrophages are thus consistent with specific PI3K-independent inhibition of p50 NFκB homodimer activity by LY2.

Anti-inflammatory effects of electroacupuncture in the respiratory system of a symptomatic amyotrophic lateral sclerosis animal model

BACKGROUND

Because amyotrophic lateral sclerosis (ALS) is a progressive inflammatory disease, treatment of the pulmonary system plays a key role in ALS patients' care. Previous studies have mainly examined the pathological mechanism of ALS in the central nervous system; however, there has been relatively little research regarding the pulmonary system in ALS animal models. In inflammatory diseases, including asthma and arthritis, electroacupuncture (EA) is commonly used for its anti-inflammatory effects. The goal of this study was to determine whether EA treatment affects inflammation in the pulmonary system in an ALS animal model.

METHODS

EA treatment at ST36 (Zusanli) acupoint was performed with 14-week-old hSOD1(G93A) transgenic mice. Immunohistochemical analysis was performed using anti-ionized calcium binding adaptor molecule 1 (Iba-1) and anti-tumor necrosis factor alpha (TNF-α) antibodies. To investigate the expression level of inflammatory proteins, Western blot analyses were performed using anti-Iba-1, anti-TNF-α, anti-nuclear factor kappa B (NF-κB), and anti-interleukin 6 (IL-6) antibodies. The activation of Ser435-phospho-specific RAC-alpha serine/threonine-protein kinase 1 (pAKT) and the increase of phosphorylated extracellular-signal-regulated kinases (pERK) protein in lung tissues of EA-treated and untreated hSOD1(G93A) mice were also evaluated by Western blot.

RESULTS

EA treatment decreased the expression of the proinflammatory proteins such as TNF-α and IL-6, pNF-κB, and Iba-1 and increased the level of activated pAKT and pERK compared to control hSOD1(G93A) mice.

CONCLUSIONS

Our findings suggest that EA could be an effective anti-inflammatory treatment for the respiratory impairment that occurs in ALS animal models.

Cannabinoid 1 receptor activation contributes to vascular inflammation and cell death in a mouse model of diabetic retinopathy and a human retinal cell line

AIMS/HYPOTHESIS

Recent studies have demonstrated that cannabinoid-1 (CB(1)) receptor blockade ameliorated inflammation, endothelial and/or cardiac dysfunction, and cell death in models of nephropathy, atherosclerosis and cardiomyopathy. However the role of CB(1) receptor signalling in diabetic retinopathy remains unexplored. Using genetic deletion or pharmacological inhibition of the CB(1) receptor with SR141716 (rimonabant) in a rodent model of diabetic retinopathy or in human primary retinal endothelial cells (HREC) exposed to high glucose, we explored the role of CB(1) receptors in the pathogenesis of diabetic retinopathy.

METHODS

Diabetes was induced using streptozotocin in C57BL/6J Cb(1) (also known as Cnr1)(+/+) and Cb(1)(-/-) mice aged 8 to 12 weeks. Samples from mice retina or HREC were used to determine: (1) apoptosis; (2) activity of nuclear factor kappa B, intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), poly (ADP-ribose) polymerase and caspase-3; (3) content of 3-nitrotyrosine and reactive oxygen species; and (4) activation of p38/Jun N-terminal kinase/mitogen-activated protein kinase (MAPK).

RESULTS

Deletion of CB(1) receptor or treatment of diabetic mice with CB(1) receptor antagonist SR141716 prevented retinal cell death. Treatment of diabetic mice or HREC cells exposed to high glucose with SR141716 attenuated the oxidative and nitrative stress, and reduced levels of nuclear factor κB, ICAM-1 and VCAM-1. In addition, SR141716 attenuated the diabetes- or high glucose-induced pro-apoptotic activation of MAPK and retinal vascular cell death.

CONCLUSIONS/INTERPRETATION

Activation of CB(1) receptors may play an important role in the pathogenesis of diabetic retinopathy by facilitating MAPK activation, oxidative stress and inflammatory signalling. Conversely, CB(1) receptor inhibition may be beneficial in the treatment of this devastating complication of diabetes.

Hypervalent organochalcogenanes as inhibitors of protein tyrosine phosphatases

A series of organochalcogenanes was synthesized and evaluated as protein tyrosine phosphatases (PTPs) inhibitors. The results indicate that organochalcogenanes inactivate the PTPs in a time- and concentration-dependent fashion, most likely through covalent modification of the active site sulfur-moiety by the chalcogen atom. Consequently, organochalcogenanes represent a new class of mechanism-based probes to modulate the PTP-mediated cellular processes.