Perfluorododecanoic acid delays Leydig cell regeneration from stem cells in adult rats.

Perfluorododecanoic acid (PFDoA) is an endocrine-damaging compound in contaminated food and water. However, the potential role and underlying mechanism of PFDoA in Leydig cell regeneration from stem Leydig cells remain unclear. The current study aims to investigate the effect of PFDoA on the regeneration of Leydig cells in the testis of rats treated with ethylene dimethane sulfonate (EDS). PFDoA (0, 5 or 10 mg/kg/day) was gavaged to adult Sprague-Dawley male rats for 8 days, and 75 mg/kg EDS was intraperitoneally injected to eliminate Leydig cells to initiate its regeneration from day 21-56 after EDS. The serum testosterone levels in the 5 and 10 mg/kg/day PFDoA groups were significantly reduced at day 21 after EDS and the levels of serum luteinizing hormone and follicle-stimulating hormone were significantly decreased in the 10 mg/kg/day PFDoA groups at day 56 after EDS. PFDoA significantly reduced Leydig cell number and proliferation at a dose of 10 mg/kg at days 21 and 56 after EDS. PFDoA significantly down-regulated the expression of Leydig cell-specific genes (Lhcgr, Scarb1, Star, Cyp11a1, Hsd3b1 and Cyp17a1) and their proteins at both doses at days 21 and 56 after EDS. PFDoA significantly down-regulated the gene expression of Sertoli cells (Fshr, Dhh, and Sox9) at 5 mg/kg or higher at days 21 and 56 after EDS. In addition, we found that PFDoA significantly inhibited EdU incorporation into putative stem Leydig cells and their differentiation into the Leydig cell lineage in vitro. In conclusion, short-term PFDoA exposure in adulthood delayed the regeneration of Leydig cells by preventing Leydig cells from stem cells via multiple mechanisms.

Investigation of acute, subacute and subchronic toxicities of anthocyanin derived acylation reaction products and evaluation of their antioxidant activities in vitro.

Previously, anthocyanins were successfully acylated with lauric acid using Novozym 435 lipase, and the corresponding products were confirmed to have higher stability. As novel synthetic compounds, their toxicological safety has not been evaluated. Therefore, acute, subacute and subchronic toxicities of anthocyanin-lauric acid derivatives (ALDs) were investigated while their antioxidant activities were also evaluated in vitro. The acute toxicity results showed that the 50% lethal dose (LD50) of ALDs in mice was >10 g kg-1. Subsequently, the subacute toxicity test was conducted by oral administration of ALDs at doses of 0.63, 1.25 and 2.50 g kg-1 for 28 days. No adverse effect of ALDs on body weight, food/water intake, organ coefficient and histology was observed. Though there were some fluctuations in AST and ALT, the tested biochemical parameters were maintained within the normal ranges. The subchronic toxicity test results demonstrated that less than 0.60 g of ALDs per kg BW intake did not affect mortality, body weight, food/water intake, gross pathology, histology, hematology and serum biochemistry. Furthermore, cyanidin-3-(6''-dodecanoyl)-glucoside, the main component of ALDs, had a beneficial reducing power and a strong DPPH˙, ABTS+˙, and O2-˙ scavenging activity. This study provides an imperative reference to the safety of ALDs, suggesting their application as novel colorants or antioxidants in food and therapeutics.

Oxidative stress and mitochondrial membrane potential are involved in the cytotoxicity of perfluorododecanoic acid to neurons.

Perfluorododecanoic acid (PFDoA), used in numerous commercial products, was recently demonstrated to accumulate in the brain more easily than other perfluorinated compounds and to cause cognitive deficits. In this study, pheochromocytoma 12 (PC12) cells were exposed to doses of PFDoA to explore the cytotoxicity of this compound to neurons. The results showed that treatment with PFDoA decreased PC12 cell viability dose-dependently. Treatment with 50 and 100 µM PFDoA significantly increased reactive oxygen species (p < 0.01) and malondialdehyde (p < 0.01) and decreased total antioxidant capacity (p < 0.05 and p < 0.01, respectively) in PC12 cells. The administration of 50 and 100 µM PFDoA led to a loss of mitochondrial membrane potential (MMP) (p < 0.05 and p < 0.01, respectively) in PC12 cells. The activity of caspase 3 was obviously increased (p < 0.05) in 100 µM PFDoA-treated PC12 cells. In general, the results demonstrated that PFDoA exposure could result in the disruption of MMP, which may contribute to the increase of oxidative stress and activation of the apoptotic signaling cascade in PC12 cells.

Comparative study of different forms of Jellein antimicrobial peptide on Leishmania parasite.

Typically, antimicrobial peptides (AMPs) are short positive charged peptides serving a key role in innate immunity as well as antimicrobial activity. Discovering novel therapeutic agents is considered as an undeniable demand due to increasing microbial species with antibiotic resistance. In this direction, the unique ability of AMPs to modulate immune responses highlighted them as novel drug candidates in the field of microbiology. Patients affected by leishmaniasis; a neglected tropical disease, confront serious problems for their treatment including resistance to common drugs as well as toxicity and high cost of therapy. So, there is a need for development of new drug candidates to control the diseases. Jellein, a peptide derived from royal jelly of honeybee has been shown to have promising effect against several bacterial and fungal species. In current study, anti-leishmanial effect of Jellein and its lauric acid conjugated form was investigated against two forms of Leishmania major (L. major) parasite. Moreover, cytotoxic effect of these peptides was studied in THP1 cell line and human Red Blood Cells (RBCs). Furthermore, the mechanism of action of peptides on L. major promastigotes was assessed through different methods. The results demonstrated that, conjugation of lauric acid to Jellein not only had no effect on the elevation of antimicrobial activity but also halted it completely. Moreover, Jellein caused a limitation in the number of L. major promastigotes by pore formation as well as changing the membrane potential rather than induction of apoptosis or activation of caspases.

Perfluorododecanoic Acid Blocks Rat Leydig Cell Development during Prepuberty.

Perfluorododecanoic acid (PFDoA) has been used as a surfactant and may have reproductive toxicity. However, whether PFDoA influences Leydig cell development during prepuberty remains unknown. In the present study, 21-day-old male Sprague-Dawley rats were gavaged 0, 5, or 10 mg/kg PFDoA from postnatal day 21 to 35. PFDoA decreased the serum concentrations of testosterone, luteinizing hormone, and follicle-stimulating hormone at doses of 5 and 10 mg/kg without influencing Leydig cell number and proliferation. However, PFDoA down-regulated the expression of Leydig cell genes ( Lhcgr, Scarb1, Star, Cyp11a1, Cyp17a1, and Hsd11b1) or their proteins. PFDoA dose-dependently reduced SIRT1 and PGC-1α levels. PFDoA did not affect AMPK and AKT2 levels but decreased their phosphorylation. We also treated primary progenitor Leydig cells purified from prepubertal rat testes with PFDoA for 24 h. It in vitro lowered viability and decreased mitochondrial membrane potential of progenitor Leydig cells, but it stimulated the generation of the intracellular reactive oxygen species and induced Leydig cell apoptosis at 10 µM. In conclusion, PFDoA blocks rat Leydig cell development during the prepubertal period possibly via targeting AMPK/SIRT1/PGC-1α and AKT2 signaling pathways.

Perfluorododecanoic acid exposure induced developmental neurotoxicity in zebrafish embryos.

Perfluorododecanoic acid (PFDoA), an artificial perfluorochemical, has been widely distributed in different ambient media and has been reported to have the potential to cause developmental neurotoxicity. However, the specific mechanism is largely unknown. In the current study, zebrafish embryos were treated with 0, 0.24, 1.2, and 6 mg/L PFDoA for 120 h. Exposure to PFDoA causes serious decreases in hatching delay, body length, as well as decreased locomotor speed in zebrafish larvae. Additionally, the acetylcholine (ACh) content as well as acetylcholinesterase (AChE) activity were determined to be significantly downregulated in PFDoA treatment groups. The level of dopamine was upregulated significantly after treating with 1.2 and 6 mg/L of PFDoA. Gene expressions related to the nervous system development were also analyzed, with the exception of the gene mesencephalic astrocyte-derived neurotrophic factor (manf), which is upregulated in the 6 mg/L treatment group. All other genes were significantly downregulated in larvae in the PFDoA group in different degrees. In general, the results demonstrated that PFDoA exposure could result in the disruption of the cholinergic system, dopaminergic signaling, and the central nervous system.

Exposure to PFDoA causes disruption of the hypothalamus-pituitary-thyroid axis in zebrafish larvae.

Perfluorododecanoic acid (PFDoA), a kind of perfluorinated carboxylic acid (PFCA) with 12 carbon atoms, has an extensive industrial utilization and is widespread in both wildlife and the water environment, and was reported to have the potential to cause a disruption in the thyroid hormone system homeostasis. In this study, zebrafish embryos/larvae were exposed to different concentrations of PFDoA (0, 0.24, 1.2, 6 mg/L) for 96 h post-fertilization (hpf). PFDoA exposure caused obvious growth restriction connected with the reduced thyroid hormones (THs) contents in zebrafish larvae, strengthening the interference effect on the growth of fish larvae. The transcriptional level of genes within the hypothalamic-pituitary-thyroid (HPT) axis was analyzed. The gene expression levels of thyrotropin-releasing hormone (trh) and corticotrophin-releasing hormone (crh) were upregulated upon exposure to 6 mg/L of PFDoA, and iodothyronine deiodinases (dio2) was upregulated in the 1.2 mg/L PFDoA group. The transcription of thyroglobulin (tg) and thyroid receptor (trß) were significantly downregulated upon exposure to 1.2 mg/L and 6 mg/L of PFDoA. PFDoA could also decrease the levels of sodium/iodide symporter (nis) and transthyretin (ttr) gene expression in a concentration-dependent manner after exposure. A significant decrease in thyroid-stimulating hormoneß (tshß), uridinediphosphate-glucuronosyltransferase (ugt1ab) and thyroid receptor (trα) gene expression were observed at 6 mg/L PFDoA exposure. Upregulation and downregulation of iodothyronine deiodinases (dio1) gene expression were observed upon the treatment of 1.2 mg/L and 6 mg/L PFDoA, respectively. All the data demonstrated that gene expression in the HPT axis altered after different PFDoA treatment and the potential mechanisms of the disruption of thyroid status could occur at several steps in the process of synthesis, regulation, and action of thyroid hormones.

Peak AAA fatty acid homolog contaminants present in the dietary supplement l-Tryptophan associated with the onset of eosinophilia-myalgia syndrome.

The eosinophilia-myalgia syndrome (EMS) outbreak that occurred in the USA and elsewhere in 1989 was caused by the ingestion of Showa Denko K.K. (SD) L-tryptophan (L-Trp). "Six compounds" detected in the L-Trp were reported as case-associated contaminants. Recently the final and most statistically significant contaminant, "Peak AAA" was structurally characterized. The "compound" was actually shown to be two structural isomers resulting from condensation reactions of L-Trp with fatty acids derived from the bacterial cell membrane. They were identified as the indole C-2 anteiso (AAA1-343) and linear (AAA2-343) aliphatic chain isomers. Based on those findings, we utilized a combination of on-line HPLC-electrospray ionization mass spectrometry (LC-MS), as well as both precursor and product ion tandem mass spectrometry (MS/MS) to facilitate identification of a homologous family of condensation products related to AAA1-343 and AAA2-343. We structurally characterized eight new AAA1-XXX/AAA2-XXX contaminants, where XXX represents the integer molecular ions of all the related homologs, differing by aliphatic chain length and isomer configuration. The contaminants were derived from the following fatty acids of the bacterial cell membrane, 5-methylheptanoic acid (anteiso-C8:0) for AAA1-315; n-octanoic acid (n-C8:0) for AAA2-315; 6-methyloctanoic acid (anteiso-C9:0) for AAA1-329; n-nonanoic acid (n-C9:0) for AAA2-329; 10-methyldodecanoic acid (anteiso-C13:0) for AAA1-385; n-tridecanoic acid (n-C13:0) for AAA2-385; 11-methyltridecanoic acid (anteiso-C14:0) for AAA1-399; and n-tetradecanoic acid (n-C14:0) for AAA2-399. The concentration levels for these contaminants were estimated to be 0.1-7.9 µg / 500 mg of an individual SD L-Trp tablet or capsule The structural similarity of these homologs to case-related contaminants of Spanish Toxic Oil Syndrome (TOS) is discussed.

Perfluorododecanoic Acid Induces Cognitive Deficit in Adult Rats.

The brain level of perfluorododecanoic acid (PFDoA) was compared with those of perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) in rats 9 days after a single oral dose (50 mg/kg). The PFDoA level in the brain was 44.0 ± 2.0 µg/g, which was higher than that in the serum (24.4 ± 1.0 µg/ml). In contrast, the concentrations of PFOA and PFDA in the brain were low (<0.8 and 4.7 ± 0.4 µg/g, respectively), and less than one-tenth of those in the serum. Next, to investigate the effects on brain function, the cognitive function alterations of PFOA, PFDA, and PFDoA were estimated by the novel object recognition test 5-6 days after dosing. A significant decrease in the discrimination index was observed in PFDoA-treated rats while no significant alteration was observed in PFDA- and PFOA-treated rats. The effects of PFDoA were further assessed by other behavioral tests. PFDoA-associated alteration was observed in the elevated-plus maze test, but not in the Y-maze test, open-field test, and forced swim test. A decrease in the discrimination index of the novel object recognition test was dependent on the PFDoA dose and the PFDoA concentration in the brain. PFDoA concentration in the brain was 28.6 ± 2.6 µg/g 30 days after dosing, and a decrease in discrimination index was observed. Taken together, these results suggest that PFDoA distributes in the brain easier than PFOA and PFDA and causes cognitive deficit.

A simple method for isolation and construction of markerless cyanobacterial mutants defective in acyl-acyl carrier protein synthetase.

Cyanobacterial mutants defective in acyl-acyl carrier protein synthetase (Aas) secrete free fatty acids (FFAs) into the external medium and hence have been used for the studies aimed at photosynthetic production of biofuels. While the wild-type strain of Synechocystis sp. PCC 6803 is highly sensitive to exogenously added linolenic acid, mutants defective in the aas gene are known to be resistant to the externally provided fatty acid. In this study, the wild-type Synechocystis cells were shown to be sensitive to lauric, oleic, and linoleic acids as well, and the resistance to these fatty acids was shown to be enhanced by inactivation of the aas gene. On the basis of these observations, we developed an efficient method to isolate aas-deficient mutants from cultures of Synechocystis cells by counter selection using linoleic acid or linolenic acid as the selective agent. A variety of aas mutations were found in about 70 % of the FFA-resistant mutants thus selected. Various aas mutants were isolated also from Synechococcus sp. PCC 7002, using lauric acid as a selective agent. Selection using FFAs was useful also for construction of markerless aas knockout mutants from Synechocystis sp. PCC 6803 and Synechococcus sp. PCC 7002. Thus, genetic engineering of FFA-producing cyanobacterial strains would be greatly facilitated by the use of the FFAs for counter selection.

Activation of peroxisome proliferator-activated receptor α ameliorates perfluorododecanoic acid-induced production of reactive oxygen species in rat liver.

Perfluorododecanoic acid (PFDoA) is a ubiquitous environmental pollutant known to cause hepatocellular hypertrophy; however, the mechanisms of hepatotoxicity remain poorly understood. In this study, male rats were exposed to 0, 0.05, 0.2 and 0.5 mg/kg/day of PFDoA for 110 days. After two-dimensional differential gel electrophoresis and MALDI-TOF/TOF analysis, 73 differentially expressed proteins involved in lipid metabolism, inflammation, stress response and other functions were successfully identified. Among them, six significantly changed proteins (CTE1, MTE1, HADHA, ECH1, ALDH2 and CPS1) were found to be regulated by peroxisome proliferator-activated receptor alpha (PPARα). The anti-oxidant enzyme activity assays of superoxide dismutase and glutathione peroxidase and the content of thiobarbituric acid-reactive substances in the liver implied that PFDoA caused oxidative stress. The mRNA levels of PPARα in rat primary hepatocytes were knocked down by lentivirus-mediated RNAi. Furthermore, targeted protein levels of CTE1 and MTE1 were down-regulated, while those of HADHA, ALDH2 and CPS1 were up-regulated. After PFDoA exposure, however, the targeted protein levels of CTE1 and ALDH2 increased compared with those of the knockdown untreated group. The reactive oxygen species (ROS) content in rat hepatocytes assayed by flow cytometry significantly increased in the PPARα knockdown groups, consistent with the PPARα antagonist GW6471- and agonist WY14643-treated groups. These results strongly suggested that PPARα played an important role in suppressing ROS content in hepatocytes following PFDoA exposure.

Dietary Fatty Acids Directly Impact Central Nervous System Autoimmunity via the Small Intestine.

Growing empirical evidence suggests that nutrition and bacterial metabolites might impact the systemic immune response in the context of disease and autoimmunity. We report that long-chain fatty acids (LCFAs) enhanced differentiation and proliferation of T helper 1 (Th1) and/or Th17 cells and impaired their intestinal sequestration via p38-MAPK pathway. Alternatively, dietary short-chain FAs (SCFAs) expanded gut T regulatory (Treg) cells by suppression of the JNK1 and p38 pathway. We used experimental autoimmune encephalomyelitis (EAE) as a model of T cell-mediated autoimmunity to show that LCFAs consistently decreased SCFAs in the gut and exacerbated disease by expanding pathogenic Th1 and/or Th17 cell populations in the small intestine. Treatment with SCFAs ameliorated EAE and reduced axonal damage via long-lasting imprinting on lamina-propria-derived Treg cells. These data demonstrate a direct dietary impact on intestinal-specific, and subsequently central nervous system-specific, Th cell responses in autoimmunity, and thus might have therapeutic implications for autoimmune diseases such as multiple sclerosis.

Repeated dose and reproductive/developmental toxicity of perfluorododecanoic acid in rats.

Perfluoroalkyl carboxylic acids (PFCAs) are a series of environmental contaminants that have received attention because of their possible adverse effects on wildlife and human health. Although many toxicological studies have been performed on perfluorooctanoic acid with carbon chain length C8, available toxicity data on PFCAs with longer chains are still insufficient to evaluate their hazard. A combined repeated dose and reproductive/developmental toxicity screening study for perfluorododecanoic acid (PFDoA; C12) was conducted in accordance with OECD guideline 422 to fill these toxicity data gaps. PFDoA was administered by gavage to male and female rats at 0.1, 0.5, or 2.5 mg/kg/day. The administration of PFDoA at 0.5 and 2.5 mg/kg/day for 42-47 days mainly affected the liver, in which hypertrophy, necrosis, and inflammatory cholestasis were noted. Body weight gain was markedly inhibited in the 2.5 mg/kg/day group, and a decrease in hematopoiesis in the bone marrow and atrophic changes in the spleen, thymus, and adrenal gland were also observed. Regarding reproductive/developmental toxicity, various histopathological changes, including decreased spermatid and spermatozoa counts, were observed in the male reproductive organs, while continuous diestrous was observed in the females of the 2.5 mg/kg/day group. Seven of twelve females receiving 2.5 mg/kg/day died during late pregnancy while four other females in this group did not deliver live pups. No reproductive or developmental parameters changed at 0.1 or 0.5 mg/kg/day. Based on these results, the NOAELs of PFDoA were concluded to be 0.1 mg/kg/day for repeated dose toxicity and 0.5 mg/kg/day for reproductive/developmental toxicity.

Reaction and catalyst engineering to exploit kinetically controlled whole-cell multistep biocatalysis for terminal FAME oxyfunctionalization.

The oxyfunctionalization of unactivated C−H bonds can selectively and efficiently be catalyzed by oxygenase-containing whole-cell biocatalysts. Recombinant Escherichia coli W3110 containing the alkane monooxygenase AlkBGT and the outer membrane protein AlkL from Pseudomonas putida GPo1 have been shown to efficiently catalyze the terminal oxyfunctionalization of renewable fatty acid methyl esters yielding bifunctional products of interest for polymer synthesis. In this study, AlkBGTL-containing E. coli W3110 is shown to catalyze the multistep conversion of dodecanoic acid methyl ester (DAME) via terminal alcohol and aldehyde to the acid, exhibiting Michaelis-Menten-type kinetics for each reaction step. In two-liquid phase biotransformations, the product formation pattern was found to be controlled by DAME availability. Supplying DAME as bulk organic phase led to accumulation of the terminal alcohol as the predominant product. Limiting DAME availability via application of bis(2-ethylhexyl)phthalate (BEHP) as organic carrier solvent enabled almost exclusive acid accumulation. Furthermore, utilization of BEHP enhanced catalyst stability by reducing toxic effects of substrate and products. A further shift towards the overoxidized products was achieved by co-expression of the gene encoding the alcohol dehydrogenase AlkJ, which was shown to catalyze efficient and irreversible alcohol to aldehyde oxidation in vivo. With DAME as organic phase, the aldehyde accumulated as main product using resting cells containing AlkBGT, AlkL, as well as AlkJ. This study highlights the versatility of whole-cell biocatalysis for synthesis of industrially relevant bifunctional building blocks and demonstrates how integrated reaction and catalyst engineering can be implemented to control product formation patterns in biocatalytic multistep reactions.

Sex difference in urocortin production is contributory to the gender disparity in a rat model of vasculitis induced by sodium laurate.

Cardiovascular diseases, the most common leading death diseases, occur more in men than women of the same ages. Increasing evidence shows that urocortin (Ucn1), an autocrine or paracrine pro-inflammatory factor, can be regulated by sex hormones. The purpose of the study is to investigate the role of Ucn1 in gender disparity in a sodium laurate-induced vasculitis model. Rats exhibited visible signs of vasculitis on the 14th day after sodium laurate injection. Inflammatory states of the rat femoral artery were observed by histological examination. Significant gender disparity, with the symptoms much grosser in males than females, was seen. In males, the serum levels of Ucn1, prostaglandin estradiol, and soluble intercellular adhesion molecule-1 and the expressions of Ucn1, cyclooxygenase-2, and intercellular adhesion molecule-1 in femoral artery were higher than those in females. Orchidectomy significantly ameliorated the symptoms of vasculitis accompanied with a decrease in the plasma Ucn1 level. However, estradiol supplement after orchidectomy failed to improve the inflammatory states further. In females, ovariectomy and/or dihydrotestosterone supplement significantly increased Ucn1 level and exacerbated symptoms of vasculitis. Furthermore, ip administration of rabbit antiserum to Ucn1 almost abolished the gender differences in vasculitis. These results demonstrated that vasculitis of this model is androgen-responsive and hormonal manipulation by surgical orchidectomy could substantially attenuate the symptoms of vasculitis. Moreover, Ucn1 is a contributory factor to the gender disparity in vasculitis and dihydrotestosterone-promoted Ucn1 secretion exacerbated the development of vasculitis.

Testicular phosphoproteome in perfluorododecanoic acid-exposed rats.

Perfluorododecanoic acid (PFDoA) is a common environmental pollutant, which has been detected in human sera and has adverse effects on testicular function in animal models. Exploring phosphorylation events in testes helps elucidate the specific phosphorylation signals involved in testicular toxicity of PFDoA. Combining efficient prefractionation of tryptic peptide mixtures using self-packed reversed phase C18 columns with TiO2 and IMAC phosphopeptide enrichment techniques followed by 2D-LC-MS/MS, we identified 4077 unique phosphopeptides from 1777 proteins with a false discovery rate below 1.0% in the testes of rats exposed to PFDoA for 110 days. In addition, 937 novel phosphorylation sites were discovered in testicular proteins. Hundreds of phosphorylated proteins identified might be involved in spermatogenesis and sperm function. With increasing PFDoA dosage, the number of casein kinase 2 kinase-modified peptides significantly increased. Pathway analysis suggested that the mitogen-activated protein kinase pathway and cell division cycle protein 2 (CDC2) may have contributed to sperm activity and testicular function. By in vitro experiments, CDC2 phosphorylation activity was found to be likely involved in PFDoA-induced toxicity in Leydig cells. This study provides the first examination of the whole proteins' phosphorylation profile in rat testis and suggests that the MAPK pathway and CDC2 protein phosphorylation are critical for PFDoA testicular toxicity.

Effective inhibition of acid and neutral ceramidases by novel B-13 and LCL-464 analogues.

Induction of apoptosis mediated by the inhibition of ceramidases has been shown to enhance the efficacy of conventional chemotherapy in several cancer models. Among the inhibitors of ceramidases reported in the literature, B-13 is considered as a lead compound having good in vitro potency towards acid ceramidase. Furthermore, owing to the poor activity of B-13 on lysosoamal acid ceramidase in living cells, LCL-464 a modified derivative of B-13 containing a basic ω-amino group at the fatty acid was reported to have higher potency towards lysosomal acid ceramidase in living cells. In a search for more potent inhibitors of ceramidases, we have designed a series of compounds with structural modifications of B-13 and LCL-464. In this study, we show that the efficacy of B-13 in vitro as well as in intact cells can be enhanced by suitable modification of functional groups. Furthermore, a detailed SAR investigation on LCL-464 analogues revealed novel promising inhibitors of aCDase and nCDase. In cell culture studies using the breast cancer cell line MDA-MB-231, some of the newly developed compounds elevated endogenous ceramide levels and in parallel, also induced apoptotic cell death. In summary, this study shows that structural modification of the known ceramidase inhibitors B-13 and LCL-464 generates more potent ceramidase inhibitors that are active in intact cells and not only elevates the cellular ceramide levels, but also enhances cell death.

Phosphoproteome analysis reveals an important role for glycogen synthase kinase-3 in perfluorododecanoic acid-induced rat liver toxicity.

Perfluorododecanoic acid (PFDoA) is a member of the perfluoroalkyl acid (PFAA) family and has broad applications and a wide distribution in the environment. Here, we used TiO(2)-based phosphopeptide enrichment coupled with LC-MS/MS analysis to identify phosphopeptides in rat livers that were influenced by PFDoA treatment. We identified a total of 1443 unique phosphopeptides from among 769 phosphoproteins identified in normal and PFDoA-treated rat livers, 849 unique phosphorylation sites were also identified. Of these sites, 143 were considered to be novel phosphorylation sites. Many phosphoproteins were found to be associated with hepatic injuries and diseases, such as hepatotoxicity, regeneration, fatty liver, neoplasms and carcinoma. Furthermore, 25 of the identified phosphoproteins were found to be related to glycogen synthase kinase-3 (GSK3), either directly or indirectly. Western blot and qPCR results suggested that chronic PFDoA exposure inhibited insulin signal pathways and that inhibition of GSK3 might contribute to the observed increases of lipid levels in the liver.

Safety of medium-chain triglycerides used as an intraocular tamponading agent in an experimental vitrectomy model rabbit.

PURPOSE: To evaluate safety of medium-chain triglycerides used as a possible intraocular tamponading agent. METHODS: A 20-gauge pars plana vitrectomy was performed in the right eye of 28 rabbits. An ophthalmologic examination was performed every week until rabbits were killed. At days 7, 30, 60, and 90, rabbits were killed and the treated eyes were examined macroscopically and prepared for histologic examination. Principal outcome was retinal toxicity evaluated by light and electron microscopy, and secondary outcomes were the presence of medium-chain triglyceride emulsification, inflammatory reactions, and the development of cataract. RESULTS: Histologic examination did not reveal any retinal toxicity. Two cases of moderate emulsification were observed, but in these cases, emulsification was caused by the perioperative injection of the agent and did not increase during the postoperative period. We noted 13 cases of inflammatory reaction in vitreous cavity and no case of inflammatory reaction in anterior chamber. Two eyes developed cataract as a result of perioperative trauma to the lens with the vitreous cutter and not secondary to the presence of medium-chain triglycerides in the vitreous cavity. CONCLUSION: Medium-chain triglycerides did not induce morphologic evidence of retinal toxicity. The results suggest that medium-chain triglycerides could be a promising alternative intraocular tamponading agent for the treatment of retinal detachments.