Apoptotic and antiproliferative properties of 3β‐hydroxy‐Δ5‐steroidal congeners from a partially purified column fraction of Dendronephthya gigantea against HL‐60 and MCF‐7 cancer cells

Organisms belonging to the genus Dendronephthya are among a group of marine invertebrates that produce a variety of terpenoids with biofunctional properties. Many of these terpenoids have been proven effective as anticancer drugs. Here, we report the antiproliferative effect of 3β‐hydroxy‐Δ5‐steroidal congeners against the proliferation of HL‐60 human leukemia cells and MCF‐7 human breast cancer cells. The sterol‐rich fraction (DGEHF2‐1) inhibited the growth of HL‐60 and MCF‐7 cells with IC₅₀ values of 13.59 ± 1.40 and 29.41 ± 0.87 μg ml^–1 respectively. Treatment with DGEHF2‐1 caused a dose‐dependent increase in apoptotic body formation, DNA damage and the sub‐G₁ apoptotic cell population. Moreover, DGEHF2‐1 downregulated the expression of Bcl‐xL while upregulating Bax, caspase‐9, and PARP cleavage in both HL‐60 and MCF‐7 cells. The steroid fraction was found to act via the mitochondria‐mediated apoptosis pathway. Identification of the sterols was performed via gas chromatography–tandem mass spectrometry analysis. Studying the mechanism of the anticancer effect caused by these sterol derivatives could lead to the identification of other natural products with anticancer properties.     

Amifostine protection against induced DNA damage in γ‐irradiated Escherichia coli cells depend on recN DNA repair gene product activity

Amifostine is the most effective radioprotector known and the only one accepted for clinical use in cancer radiotherapy. In this work, the antigenotoxic effect of amifostine against γ‐rays was studied in Escherichia coli cells deficient in DNA damage repair activities. Assays of irradiated cells treated with amifostine showed that the drug reduced the genotoxicity induced by radiation in E. coli wild‐type genotypes and in uvr, recF, recB, recB‐recC‐recF mutant strains, but not in recN defective cells. Thus, the mechanism of DNA protection by amifostine against γ‐radiation‐induced genotoxicity appears to involve participation of the RecN protein that facilitates repair of DNA double‐strand breaks. The results are discussed in relation to amifostine's chemopreventive potential. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2010.     

Semiquinone fraction isolated from Bacillus sp. INM‐1 protects hepatic tissues against γ‐radiation induced toxicity

Present study was focused on evaluation of a semiquinone glucoside derivative (SQGD) isolated from radioresistant bacterium Bacillus sp. INM‐1 for its ability against γ radiation induced oxidative stress in irradiated mice. Animals were divided into four group, i.e., (i) untreated control mice; (ii) SQGD treated (50 mg/kg b. wt. i.p.) mice; (iii) irradiated (10 Gy) mice; and (iv) irradiated mice which were pre‐treated (?2 h) with SQGD (50 mg/kg b. wt. i.p.). Following treatment, liver homogenates of the treated mice were subjected to endogenous antioxidant enzymes estimation. Result indicated that SQGD pre‐treatment, significantly (P < 0.05) induced superoxide dismutase (SOD) (19.84 ± 2.18% at 72 h), catalase (CAT) (26.47 ± 3.11% at 12 h), glutathione (33.81 ± 1.99% at 24 h), and glutathione‐S‐transferase (24.40 ± 2.65% at 6 h) activities in the liver of mice as compared with untreated control. Significant (P < 0.05) induction in SOD (50.04 ± 5.59% at 12 h), CAT (62.22 ± 7.50 at 72 h), glutathione (42.92 ± 2.28% at 24 h), and glutathione‐S‐transferase (46.65 ± 3.25 at 12 h) was observed in irradiated mice which were pre‐treated with SQGD compared with only irradiated mice. Further, significant induction in ABTS⁺ radicals (directly proportional to decrease mM Trolox equivalent) was observed in liver homogenate of H₂O₂ treated mice which were found to be significantly inhibited in H₂O₂ treated mice pre‐treated with SQGD. Thus, it can be concluded that SQGD treatment neutralizes oxidative stress caused by irradiation not only by enhancing endogenous antioxidant enzymes but also by improving total antioxidant status of cellular system and thus cumulative effect of the phenomenon may contributes to radioprotection. © 2013 Wiley Periodicals, Inc. Environ Toxicol 29: 1471–1478, 2014.     

Semiquinone glucoside derivative provides protection against γ‐radiation by modulation of immune response in murine model

Present study was undertaken to evaluate radioprotective and immunomodulatory activities of a novel semiquinone glucoside derivative (SQGD) isolated from Bacillus sp. INM‐1 in C₅₇BL/6 mice. Whole body survival study was performed to evaluate in vivo radioprotective efficacy of SQGD. To observe effect of SQGD on immunostimulation, Circulatory cytokine (i.e., interleukin‐2 (IL‐2), IFN‐γ, IL‐10, granulocyte colony stimulating factor (G‐CSF), granulocyte macrophage colony stimulating factor (GM‐CSF), and macrophage colony stimulating factor (M‐CSF) expression was analyzed in serum of irradiated and SQGD treated mice at different time intervals using ELISA assay. Results of the present investigation indicated that SQGD pre‐treatment (‐2 h) to lethally irradiated mice provide ～83% whole body survival compared with irradiated mice where no survival was observed at 30^th post irradiation day. Significant (p < 0.05) induction in IL‐2 and IFN‐γ expression was observed at all tested time intervals with SQGD pre‐treated irradiated mice as compared with irradiated mice alone. However, sharp increase in IL‐10 expression was observed in irradiated mice which were found to be subsidized in irradiated mice pre‐treated with SQGD. Similarly, significant (p < 0.05%) induction in G‐CSF, M‐CSF and GM‐CSF expression was observed in irradiated mice treated with SQGD as compared with irradiated control mice at tested time intervals. In conclusion, SQGD pre‐treatment to irradiated mice enhanced expression of IL‐12 and IFN‐γ while down‐regulated IL‐10 expression and thus modulates cytoprotective pro‐inflammatory TH₁ type immune response in irradiated mice. Further, SQGD pre‐treatment to irradiated mice accelerate G‐CSF, GM‐CSF and M‐CSF expression suggesting improved haematopoiesis and enhanced cellular immune response in immuno‐compromised irradiated mice that may contribute to in vivo radiation protection. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 478–488, 2016.     

Diallyl sulfide alleviates cisplatin‐induced nephrotoxicity in rats via suppressing NF‐κB downstream inflammatory proteins and p53/Puma signalling pathway

Despite being a potent anticancer drug, nephrotoxicity is an adverse effect which renders the clinical use of cisplatin (Cis) limited. The protective role of diallyl sulfide (DAS); a naturally occurring organo‐sulfide, present in garlic, in cisplatin‐induced nephrotoxicity has been reported earlier. However, the mechanism through which DAS exerts its nephroprotective activity remains elusive. The aim of the current study was to elucidate the possible mechanisms underlying the reno‐protective effect of DAS in cisplatin‐induced nephrotoxicity in rats. DAS was given at 2 dose levels; 50 and 100 mg/kg, orally for 4 consecutive days, starting 1 hour after administration of single dose of cisplatin (3.5 mg/kg, intraperitoneally [i.p.]). The Cis‐induced elevation in serum urea and creatinine, degree of histopathological alterations was significantly ameliorated in cisplatin groups co‐treated with DAS. In addition, DAS significantly restored Cis‐depleted glutathione (GSH) content and superoxide dismutase (SOD) activity and attenuated Cis‐elevated Malondialdehyde (MDA) level. Also, DAS significantly reduced Cis‐increased renal expression of nuclear factor kappa B (NF‐κB) and subsequent pro‐inflammatory mediators; tumour necrosis factor alpha (TNF‐α), interleukin‐1β (IL‐1β), intercellular adhesion molecule‐1 (ICAM‐1) and inducible nitric oxide synthase (iNOS) in kidney tissues. Moreover, co‐treatment with DAS significantly inhibited Cis‐increased caspase‐8 and ‐9 levels. Additionally, DAS significantly mitigated Cis‐induced protein expression of p53, Puma, and Bax while, it significantly restored Cis‐reduced protein expression of Bcl‐xL compared to the Cis group. In conclusion, these results demonstrate that DAS ameliorates cisplatin‐induced nephrotoxicity in rats through enhancement of antioxidant defense, reduction of inflammatory cytokine tissue levels as well as inhibition of apoptosis via p53/Puma signalling pathway.     

Virtual screening,SAR, and discovery of 5‐(indole‐3‐yl)‐2‐[(2‐nitrophenyl)amino] [1,3,4]‐oxadiazole as a novel Bcl‐2 inhibitor

A new series of oxadiazoles were designed to act as inhibitors of the anti‐apoptotic Bcl‐2 protein. Virtual screening led to the discovery of new hits that interact with Bcl‐2 at the BH3 binding pocket. Further study of the structure–activity relationship of the most active compound of the first series, compound 1 , led to the discovery of a novel oxadiazole analogue, compound 16j , that was a more potent small‐molecule inhibitor of Bcl‐2. 16j had good in vitro inhibitory activity with submicromolar IC₅₀ values in a metastatic human breast cancer cell line (MDA‐MB‐231) and a human cervical cancer cell line (HeLa). The antitumour effect of 16j is concomitant with its ability to bind to Bcl‐2 protein as shown by an enzyme‐linked immunosorbent assay (IC₅₀ = 4.27 μm ). Compound 16j has a great potential to develop into highly active anticancer agent.     

Multisite phosphorylation of Bcl‐2 via protein kinase Cδ facilitates apoptosis of hypertrophic cardiomyocytes

Activated protein kinase Cδ (PKCδ) associated with cardiac hypertrophy moves from the cytoplasm to the mitochondria and subsequently triggers the apoptotic signalling pathway. The underlying mechanisms remain unknown. The aim of the present study was to investigate whether mitochondrial translocation of PKCδ phosphorylates multiple sites of Bcl‐2, resulting in an imbalance between Bcl‐2 and Bak or Bax, thus enhancing the susceptibility of hypertrophic cardiomyocytes to angiotensin II (AngII)‐induced apoptosis. Chronic pressure overload was induced by transverse aortic constriction (TAC) in rats. The apoptotic rate increased in hypertrophied cardiomyocytes. In AngII‐treated hearts (10 nmol/L, 60 min), there was an increase in the number of TERMINAL deoxyribonucleotidyl transferase‐mediated dUTP–digoxigenin nick end‐labelling (TUNEL)‐positive cells; PKCδ inhibition with 500 nmol/L δV1‐1 for 60 min prevented the AngII‐induced increase in apoptosis. In the hypertrophied myocardium, PKCδ expression increased, whereas that of Bcl‐2 decreased compared with the synchronous control. Treatment of hearts with 10 nmol/L AngII for 60 min activated PKCδ and induced translocation of PKCδ to the mitochondria, where activated PKCδ facilitated the phosphorylation of Bcl‐2 at serine‐87 and serine‐70 sites. The multisite phosphorylated Bcl‐2 was released from the mitochondria, and exhibited reduced affinity for Bak and Bax. The imbalance between Bcl‐2 and Bak/Bax induced the release of mitochondrial cytochrome c and then activated the caspase 3 apoptotic pathway during AngII stimulation (10 nmol/L, 60 min) of hypertrophied cardiomyocytes. Inhibition of PKCδ reduced these effects of AngII. The results suggest that PKCδ can counteract the anti‐apoptotic effect of Bcl‐2 and may promote cardiomyocyte apoptosis through multisite phosphorylation of Bcl‐2 in hypertrophied cardiomyocytes.     

Protective effects of β‐sheet breaker α/β‐hybrid peptide against amyloid β‐induced neuronal apoptosis in vitro

Alzheimer's disease is most common neurodegenerative disorder and is characterized by increased production of soluble amyloid‐β oligomers, the main toxic species predominantly formed from aggregation of monomeric amyloid‐β (Aβ). Increased production of Aβ invokes a cascade of oxidative damages to neurons and eventually leads to neuronal death. This study was aimed to investigate the neuroprotective effects of a β‐sheet breaker α/β‐hybrid peptide (BSBHp) and the underlying mechanisms against Aβ₄₀‐induced neurotoxicity in human neuroblastoma SH‐SY5Y cells. Cells were pretreated with the peptide Aβ₄₀ to induce neurotoxicity. Assays for cell viability, cell membrane damage, cellular apoptosis, generation of reactive oxygen species (ROS), intracellular free Ca²⁺, and key apoptotic protein levels were performed in vitro. Our results showed that pretreatment with BSBHp significantly attenuates Aβ₄₀‐induced toxicity by retaining cell viability, suppressing generation of ROS, Ca²⁺ levels, and effectively protects neuronal apoptosis by suppressing pro‐apoptotic protein Bax and up‐regulating antiapoptotic protein Bcl‐2. These results suggest that α/β‐hybrid peptide has neuroprotective effects against Aβ₄₀‐induced oxidative stress, which might be a potential therapeutic agent for treating or preventing neurodegenerative diseases.     

Mechanism of the vasorelaxant effect induced by trans‐4‐methyl‐β‐nitrostyrene,a synthetic nitroderivative,in rat thoracic aorta

Mechanisms underlying the vasorelaxant effects of trans‐4‐methyl‐β‐nitrostyrene (T4MeN) were studied in rat aortic rings. In endothelium‐intact preparations, T4MeN fully and similarly relaxed contractions induced by phenylephrine (PHE) (IC₅₀ = 61.41 [35.40‐87.42] μmol/L) and KCl (IC₅₀ = 83.50 [56.63‐110.50] μmol/L). The vasorelaxant effect of T4MeN was unchanged by endothelium removal, pretreatment with L‐NAME, indomethacin, tetraethylammonium, ODQ or MDL‐12,330A. Under Ca²⁺‐free conditions, T4MeN significantly reduced with a similar potency: (i) phasic contractions induced by PHE, but not by caffeine; (ii) contractions due to CaCl₂ in aortic preparations stimulated with PHE (in the presence of verapamil) or high KCl; (iii) contractions evoked by the restoration of external Ca²⁺ levels after depletion of intracellular Ca²⁺ stores in the presence of thapsigargin. In contrast, T4MeN was more potent at inhibiting contractions evoked by the tyrosine phosphatase inhibitor, sodium orthovanadate, than those induced by the activator of PKC, phorbol‐12,13‐dibutyrate. These results suggest that T4MeN induces an endothelium‐ independent vasorelaxation that appears to occur intracellularly through the inhibition of contractions that are independent of Ca²⁺ influx from the extracellular milieu but involve phosphorylation of tyrosine residues.     

Evaluation and in vivo efficacy study of pyrano[3,2‐c]quinoline analogues as TNF‐α inhibitors

A series of pyrano[3,2 c]quinoline was evaluated for its in vivo efficacy as TNF‐α inhibitor using LPS, phosphodiesterase (PDE)‐4, and CIA assays in different mice/rat models. The synthesis was performed using one‐pot multicomponent condensation between 2,4‐dihydroxy‐1‐methylquinoline, malononitrile, and diverse un(substituted) aromatic aldehydes. In vivo efficacy of the title compounds was evaluated using LPS assay in BALB/c mice, PDE4 inhibition in ketamine–xylazine‐induced anesthetize SD rats, and CIA assay was performed in DBA/1J mice as per the standard literature protocols. The outcome of the study revealed that compound 4v was found to be most promising candidate of the series. It was efficacious with 48.8 ± 13.0% inhibition of TNF‐α release at 100 mg/kg p.o., in the LPS assay in Balb/c mice model. It was effective in PDE4 assay in ketamine–xylazine‐induced anesthetize SD rats with duration of 38.3 ± 4.5 min for reversal of anesthetic effect and also showed significant inhibition of PDE4 in salbutamol treated U937 cell assay. It was also abolished TNF‐α induced phosphorylation and degradation of IκBα. Ultimately, its effect on CIA‐related bone and cartilage damage was found statistically similar to Enbrel.     

The flavonolignan‐silymarin protects enzymatic,hematological, and immune system against γ‐radiation‐induced toxicity

The main focus of this study is evaluation of radioprotective efficacy of silymarin, a flavonolignan, against γ‐radiation‐induced damage to hematological, vital organs (liver and intestine), and immune system. Survival studies revealed that silymarin (administered orally for 3 days) provided maximum protection (67%) at 70 mg/kg body weight (b.wt.) against lethal 9 Gy γ‐irradiation (dose reduction factor = 1.27). The study revealed significant (p < 0.05) changes in levels of catalase (12.57 ± 2.58 to 30.24 ± 4.89 units), glutathione peroxidase (6.23 ± 2.95 to 13.26 ± 1.36 µg of reduced glutathione consumed/min/mg protein), glutathione reductase (0.25 ± 5.6 to 11.65 ± 2.83 pM NADPH consumed/min/mg protein), and superoxide dismutase (11.74 ± 0.2 to 16.09 ± 3.47 SOD U/mg of protein) activity at 30th day. Silymarin pretreated irradiated group exhibited increased proliferation in erythrocyte count (1.76 ± 0.41 × 10⁶ to 9.25 ± 0.24 × 10⁶), hemoglobin (2.15 ± 0.48g/dL to 14.77 ± 0.25g/dL), hematocrit (4.55 ± 0.24% to 37.22 ± 0.21%), and total leucocyte count (1.4 ± 0.15 × 10⁶ to 8.31 ± 0.47 × 10⁶) as compared with radiation control group on 15th day. An increase in CD4:CD8 ratio was witnessed (0.2–1%) at 30th day time interval using flow cytometry. Silymarin also countered radiation‐induced decrease (p < 0.05) in regulatory T‐cells (T_regs) (11.23% in radiation group at 7th day versus 0.1% in pretreated silymarin irradiated group at 15th day). The results of this study indicate that flavonolignan‐silymarin protects enzymatic, hematological, and immune system against γ‐radiation‐induced toxicity and might prove useful in management of nuclear and radiological emergencies. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 641–654, 2016.     

Effects of inhibition of hepatic sulfotransferase activity on renal genotoxicity induced by lucidin‐3‐O‐primeveroside

Sulfotransferase 1A (SULT1A) expression is lower in the liver of humans than that of rodents. Therefore, species differences should be taken into consideration when assessing the risk of rodent hepatocarcinogens metabolically activated by SULT1A in humans. Although some renal carcinogens require SULT1A‐mediated activation, it is unclear how SULT1A activity in the liver affects renal carcinogens. To explore the effects of SULT1A activity in the liver on genotoxicity induced by SULT1A‐activated renal carcinogens, B6C3F₁ mice or gpt delta mice of the same strain background were given lucidin‐3‐O‐primeveroside (LuP), a hepatic and renal carcinogen of rodents, for 4 or 13 weeks, respectively, and pentachlorophenol (PCP) as a liver‐specific SULT inhibitor, was given from 1 week before LuP treatment to the end of the experiment. A 4 week exposure of LuP induced lucidin‐specific DNA adduct formation. The suppression of Sult1a expression was observed only in the liver but not in the kidneys of PCP‐treated mice, but co‐administration of PCP suppressed LuP‐induced DNA adduct formation in both organs. Thirteen‐week exposure of LuP increased mutation frequencies and cotreatment with PCP suppressed these increases in both organs. Given that intact levels of SULT activity in the liver were much higher than in the kidneys of rodents, SULT1A may predominantly activate LuP in the liver, consequently leading to genotoxicity not only in the liver but also in the kidney. Thus, species differences should be considered in human risk assessment of renal carcinogens activated by SULT1A as in the case of the corresponding liver carcinogens.     

Role of peptide YY in 5‐fluorouracil‐induced reduction of dietary intake

5‐fluorouracil (5‐FU) is part of the standard care for cancer treatment but is associated with high incidences of appetite loss and reduced food intake, which may contribute to chemotherapy‐induced cachexia (weakness and wasting of tissue). The role of gastrointestinal satiety hormones in chemotherapy‐induced appetite loss has not been intensively investigated. Peptide YY (PYY) and glucagon‐like peptide (GLP)‐1 are important signals of gastrointestinal satiety, so this study examined the roles of these gut hormones in 5‐FU‐induced reduction of dietary intake. Mice were given 5‐FU (50 mg/kg, intraperitoneal [i.p.]) every day for 4 consecutive days. Gene expression levels of proglucagon (Pro‐Gcg), a precursor of GLP‐1, and PYY in the colon were examined by real‐time RT‐PCR. Serum levels of GLP‐1 and PYY were measured by enzyme‐linked immunosorbent assay. Some mice were pretreated with the GLP‐1 receptor antagonist exendin9–39 (1 mg/kg) or the neuropeptide Y type 2 (NPY2) receptor antagonist BIIE0246 (2 mg/kg) via the i.p. route 30 minutes before 5‐FU administration. Mice receiving 5‐FU exhibited a significant reduction in food intake that was correlated with body weight loss. These mice also showed significantly enhanced expression levels of mRNAs encoding pro‐GLP‐1 and PYY in the transverse and distal colon as well as elevated serum concentrations of GLP‐1 and PYY compared to vehicle‐treated controls. The 5‐FU‐induced reduction in food intake was attenuated by BIIE0246 but not by exendin9–39. These data suggest that administration of a NPY2 receptor antagonist may be effective for attenuating the anorexia caused by 5‐FU chemotherapy.     

β‐LAPachone ameliorates doxorubicin‐induced cardiotoxicity via regulating autophagy and Nrf2 signalling pathways in mice

β‐LAPachone (B‐LAP) is a naphthoquinone that possesses antioxidant properties. In the present investigation, the protective effect of B‐LAP against doxorubicin (DOX)‐induced cardiotoxicity was examined in mice. Thirty‐five mice were divided into 5 groups: control group, B‐LAP (5 mg/kg) group, DOX (15 mg/kg) group, DOX+B‐LAP (2.5 mg/kg) group and DOX+B‐LAP (5 mg/kg) group. B‐LAP was administered orally for 14 days of experimental period. A single dose of DOX (15 mg/kg) was injected intraperitoneally on day 3. Cardiac function, histoarchitecture, indices of oxidative stress and circulating markers of cardiac injury were examined. B‐LAP (5 mg/kg) decreased serum levels of lactate dehydrogenase (LDH), creatine kinase MB (CK‐MB) and cardiac troponin I (cTnI), and ameliorated cardiac histopathological alterations. In addition to increasing cellular NAD⁺/NADH ratio, B‐LAP up‐regulated the cardiac levels of SIRT1, beclin‐1, p‐LKB1 and p‐AMPK, and reduced the cardiac levels of p‐mTOR, interleukin (IL)‐1β, TNF (tumour necrosis factor)‐α and caspase‐3. B‐LAP also elevated the nuclear accumulation of Nrf2 and simultaneously up‐regulated the protein levels of haem oxygenase (HO‐1) and glutathione S‐transferase (GST) in the hearts of DOX mice. While B‐LAP reduced malondialdehyde concentrations in heart of DOX‐treated mice, it further promoted the activities of cardiac superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT).In accordance with increased cell survival, B‐LAP significantly improved the cardiac function of DOX mice. Collectively, these findings underline the protective potential of B‐LAP against DOX‐induced cardiotoxicity by regulating autophagy and AMPK/Nrf2 signalling pathway in mice.     

Tumour necrosis factor‐α inhibition with lenalidomide alleviates tissue oxidative injury and apoptosis in ob/ob obese mice

Lenalidomide (Revlimid; Selleck Chemicals, Houston, TX, USA), an analogue of thalidomide, possesses potent cytokine modulatory capacity through inhibition of cytokines such as tumour necrosis factor (TNF)‐α, a cytokine pivotal for the onset and development of complications in obesity and diabetes mellitus. The present study was designed to evaluate the effect of lenalidomide on oxidative stress, protein and DNA damage in multiple organs in an ob/ob murine model of obesity. To this end, C57BL/6 lean and ob/ob obese mice were administered lenalidomide (50 mg/kg per day, p.o.) for 5 days. Oxidative stress, protein and DNA damage were assessed using the conversion of reduced glutathione (GSH) to oxidized glutathione (GSSG), carbonyl formation and Comet assay, respectively. Apoptosis was evaluated using caspase 3 activity, and levels of Bax, Bcl‐2, Bip, caspase 8, caspase 9 and TNF‐α were assessed using western blot analysis. Lenalidomide treatment did not affect glucose clearance in lean or ob/ob mice. Obese mice exhibited a reduced GSH/GSSG ratio in the liver, gastrocnemius skeletal muscle and small intestine, as well as enhanced protein carbonyl formation, DNA damage and caspase 3 activity in the liver, kidney, skeletal muscle and intestine; these effects were alleviated by lenalidomide, with the exception of obesity‐associated DNA damage in the liver and kidney. Western blot analysis revealed elevated TNF‐α, Bax, Bcl‐2, Bip, caspase 8 and caspase 9 in ob/ob mice with various degrees of reversal by lenalidomide treatment. Together, these data indicate that lenalidomide protects against obesity‐induced tissue injury and protein damage, possibly in association with antagonism of cytokine production and cytokine‐induced apoptosis and oxidative stress.     

5‐Amino‐3‐methyl‐4‐isoxazolecarboxylic acid hydrazide derivatives with in vitro immunomodulatory activities

Isoxazoles are an important class of compounds of potential therapeutic value. The aim of this study was to determine immunotropic effects of 5‐amino‐3‐methyl‐4‐isoxazolecarboxylic acid hydrazide derivatives on spontaneous and mitogen‐induced lymphocyte proliferation in young and old mice, cytokine production by peritoneal cells as well as possible mechanism of action in a model of Jurkat cells. Three‐month‐old and 13‐month‐old BALB/c mice were used as donors of the cells from a thymus, a spleen, mesenteric lymph nodes, and a peritoneal cavity. Spontaneous and concanavalin A or lipopolysaccharide (LPS)‐induced cell proliferation was measured by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide colorimetric method. IL‐1β and TNF‐α production induced by LPS in macrophage‐enriched peritoneal cell cultures was measured by enzyme‐linked immunoassay. 5‐amino‐3‐methyl‐4‐isoxazolecarboxylic acid hydrazide, 01K (4‐phenyl‐1‐(5‐amino‐3‐methylisoxazole‐4‐carbonyl)‐thiosemicarbazide), and 06K (4‐(4‐chlorophenyl)‐1‐(5‐amino‐3‐methylisoxazole‐4‐carbonyl)‐thiosemicarbazide) exhibited regulatory activity in the proliferation tests. Prevailing stimulatory activity of the hydrazide and inhibitory activity of 01K and 06K was observed. Those effects were connected with different influence of the compounds on signaling proteins expression in Jurkat cells. The regulatory effects of the compounds on IL‐1β production were more profound than those on TNF‐α. Differences in the compound activity in young versus old mice were mainly restricted to 01K. Immunosuppressive isoxazole leflunomide and a stimulatory RM‐11 (1,7‐dimethyl‐8‐oxo‐1,2H‐isoxazole [5,4‐e]triazepine) were applied as reference drugs.     

Pioglitazone alleviates the mitochondrial apoptotic pathway and mito‐oxidative damage in the d‐galactose‐induced mouse model

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Novel Pentapeptide GLP‐1 (32–36) Amide Inhibits β‐Cell Apoptosis In Vitro and Improves Glucose Disposal in Streptozotocin‐Induced Diabetic Mice

We proposed that a pentapeptide, LVKGR amide, GLP‐1 (32–36) amide, derived from the gluco‐incretin hormone, glucagon‐like peptide‐1 (GLP‐1), might possess favorable actions against diabetes. Therefore, GLP‐1 (32–36) amide was synthesized and the effects of it were examined in INS‐1 cell and streptozotocin‐induced diabetic mice model. To determine the protective effects of GLP‐1 (32–36) amide on INS‐1 cell viability and apoptosis, cells were exposed to 1 μm streptozotocin (STZ) and GLP‐1 (32–36) amide for 24 h. Results showed that GLP‐1 (32–36) amide treatment decreased apoptosis rate and significantly retained cell viability compared with saline‐treated controls. Then, GLP‐1 (32–36) amide was administered intraperitoneally to streptozotocin‐induced diabetic mice with normal mice used as control. Body weight, energy intake, plasma glucose, and histopathology of the pancreas were assessed. Results showed that GLP‐1 (32–36) amide protected β‐cell viability and apoptosis against STZ‐induced toxicity, inhibited weight gain, and relieved symptoms of polydipsia. Moreover, GLP‐1 pentapeptide‐treated mice showed a slight trend toward reduced glucose excursions in intraperitoneal glucose tolerance test at the end of the experiment. GLP‐1 (32–36) amide exerted favorable protective actions in streptozotocin‐induced diabetic mice. The peptide curtailed weight gain and alleviates symptoms of polydipsia. These findings suggested the probable utility of GLP‐1 (32–36) amide, a peptide mimetic derived there from GLP‐1, for adjuvant treatment of diabetes.