Search

Background: BaeS/BaeR is a two-component system of Escherichia coli that controls the expression of porins and efflux pumps. Its role in beta-lactam resistance is limited., Objectives: To study the role of baeS/baeR two-component system in temocillin resistance in E. coli., Methods: E. coli strain BW25113 and single-gene deletion mutants related to two-component systems were collected from the KEIO collection. Double-gen deletion mutants were generated. Temocillin-resistant mutant frequencies were determined at 32 mg/L. E. coli BW25113 mutants were selected by selective pressure from serial passages. Biological costs were analysed by growth curves. Genomes of the generated mutants were sequenced. The expression level of the mdtA, mdtB, mdtC, acrD and tolC in the ΔbaeS mutant was determined by RT-PCR (with/without temocillin exposure)., Results: The frequency of temocillin mutants ranged from 2.12 × 10-8 to 4.51 × 10-8 in single-porin mutants. No mutants were recovered from E. coli BW25113 (>10-9). Selection of temocillin-resistant variants by serial passage yielded mutants up to 128 mg/L. Mutations were found in the baeS gene. Temocillin MICs ranged from 4 to 32 mg/L (highest MICs for ΔbaeS and ΔompR). The efflux pumps mdtA, mdtB, mdtC and acrD pumps were overexpressed 3-10-fold in the presence of temocillin in ΔbaeS compared to control., Conclusions: Mutations in the sensor histidine kinase, baeS, may be involved in temocillin resistance through the expression of the efflux pumps mdtABC and acrD. In addition, the low mutation rate may be a good predictor of temocillin activity., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy.)

Malignant tumors are still one of the most deadly diseases that threaten human life and health. However, developing new drugs is challenging due to lengthy trials, funding constraints, and regulatory approval procedures. Consequently, researchers have devoted themselves to transforming some clinically approved old drugs into antitumor drugs with certain active ingredients, which have become an attractive alternative. Disulfiram (DSF), an antialcohol medication, can rapidly metabolize in the physiological environment into diethyldithiocarbamate (DTC) which can readily react with Cu 2+ ions in situ to form the highly toxic bis( N , N -diethyldithiocarbamate)-copper(II) (CuET) complex. In this study, DSF is loaded into mesoporous dopamine nanocarriers and surface-chelated with tannin and Cu 2+ to construct M-MDTC nanoprodrugs under the camouflage of K7 tumor cell membranes. After intravenous injection, M-MDTC nanoprodrugs successfully reach the tumor sites with the help of mediated cell membranes. Under slightly acidic pH and photothermal stimulation conditions, DSF and Cu 2+ are simultaneously released, forming a highly toxic CuET to kill tumor cells in situ. The generated CuET can also induce immunogenic cell death of tumor cells, increase the proportion of CD86 + CD80 + cells, and promote dendritic cell maturation. In vitro and in vivo studies of M-MDTC nanoprodrugs have shown excellent tumor-cell-killing ability and solid tumor suppression. This approach enables in situ amplification of chemotherapy in the tumor microenvironment, achieving an effective antitumor treatment.

Cadaverine is an endogenous metabolite produced by the gut microbiome with various activity in physiological and pathological conditions. However, whether cadaverine regulates pain or itch remains unclear. In this study, we first found that cadaverine may bind to histamine 4 receptor (H4R) with higher docking energy score using molecular docking simulations, suggesting cadaverine may act as an endogenous ligand for H4R. We subsequently found intradermal injection of cadaverine into the nape or cheek of mice induces a dose-dependent scratching response in mice, which was suppressed by a selective H4R antagonist JNJ-7777120, transient receptor potential vanilloid 1 (TRPV1) antagonist capsazepine and PLC inhibitor U73122, but not H1R antagonist or TRPA1 antagonist or TRPV4 antagonist. Consistently, cadaverine-induced itch was abolished in Trpv1 -/- but not Trpa1 -/- mice. Pharmacological analysis indicated that mast cells and opioid receptors were also involved in cadaverine-induced itch in mice. scRNA-Seq data analysis showed that H4R and TRPV1 are mainly co-expressed on NP2, NP3 and PEP1 DRG neurons. Calcium imaging analysis showed that cadaverine perfusion enhanced calcium influx in the dissociated dorsal root ganglion (DRG) neurons, which was suppressed by JNJ-7777120 and capsazepine, as well as in the DRG neurons from Trpv1 -/- mice. Patch-clamp recordings found that cadaverine perfusion significantly increased the excitability of small diameter DRG neurons, and JNJ-7777120 abolished this effect, indicating involvement of H4R. Together, these results provide evidences that cadaverine is a novel endogenous pruritogens, which activates H4R/TRPV1 signaling pathways in the primary sensory neurons., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Defective autophagy in vascular smooth muscle cells (VSMCs) in response to oxidative stress can lead to cellular apoptosis and plaque instability. Previous studies have revealed that the circadian clock system is involved in autophagic regulation and plaque progression. However, the mechanism by which circadian rhythmicity influences VSMC autophagy and plaque stability remains unclear. Our study described the circadian profiles in atheromatous plaques and verified the role of circadian misalignment in VSMC autophagy and apoptosis. We found that the mRNA expression levels of circadian locomotor output cycles protein kaput (CLOCK) and Beclin 1 were significantly decreased in unstable plaques compared with stable plaques. No significant differences were observed in other circadian rhythm genes. VSMCs treated with oxidized low-density lipoprotein (ox-LDL, 80 μg/ml) exhibited abnormal circadian rhythmicity and impaired autophagy, as evidenced by consistent decreases in CLOCK and Beclin 1 expression, suggesting a correlation between CLOCK and autophagy. CLOCK protein expression was inhibited by ox-LDL, accompanied by defective autophagy and an increased apoptosis rates (P < 0.05). Administration of rapamycin (10 nM) reversed the effect of ox-LDL on VSMC autophagy and apoptosis. Finally, CLOCK silencing led to a considerable decrease in autophagy. VSMCs with stable CLOCK silencing also showed an increased apoptosis rate. In addition, gene silencing of CLOCK in VSMCs counteracted the effects of moderate rapamycin concentrations on autophagy and apoptosis. In conclusion, these findings suggested that the CLOCK-dependent rapamycin signaling pathway is a critical mediator in ox-LDL-induced VSMCs with defective autophagy that exacerbates plaque destabilization., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

We recently reported that necroptosis contributed to compression-induced nucleus pulposus (NP) cells death. In the current study, we investigated the regulative effect of necroptosis inhibitor Necrostatin-1 on NP cells apoptosis and autophagy. Necrostatin-1, autophagy inhibitor 3-Methyladenine and apoptosis inhibitor Z-VAD-FMK were employed, and NP cells were exposed to 1.0 MPa compression for 0, 24 and 36 h. Necroptosis-associated molecules were measured by Western blot and RT-PCR. Autophagy and apoptosis levels were evaluated by Western blot and quantified by flow cytometry after monodansylcadaverine and Annexin V-FITC/propidium iodide staining, respectively. The cell viability and cell death were also examined. Furthermore, we measured mitochondrial membrane potential (MMP), mitochondrial permeability transition pore (MPTP) and indices of oxidative stress to assess mitochondrial dysfunction. The results established that Necrostatin-1 blocked NP cells autophagy, and 3-Methyladenine had little influence on NP cells necroptosis. The Necrostatin-1+3-Methyladenine treatment exerted almost the same role as Necrostatin-1 in reducing NP cells death. Necrostatin-1 restrained NP cells apoptosis, while Z-VAD-FMK enhanced NP cells necroptosis. The Necrostatin-1+Z-VAD-FMK treatment provided more prominent role in blocking NP cells death compared with Necrostatin-1, consistent with increased MMP, reduced opening of MPTP and oxidative stress. In summary, the synergistic utilization of Necrostatin-1 and Z-VAD-FMK is a very worthwhile solution in preventing compression-mediated NP cells death, which might be largely attributed to restored mitochondrial function., Competing Interests: The authors declare that they have no conflict of interest., (Copyright © 2020 Songfeng Chen et al.)

A tight junction (TJ) makes a physical barrier in the epidermal cells of skin. Ultraviolet (UV) light may disrupt the TJ barrier, but the mechanism has not been well clarified. Weak UVB (5 mJ/cm 2 ) caused mislocalization of claudin-1 (CLDN1), a component of the TJ strand, and disruption of TJ barrier in human keratinocyte-derived HaCaT cells. The UVB-induced mislocalization of CLDN1 was inhibited by monodansylcadaverine (MDC), a clathrin-dependent endocytosis inhibitor, suggesting that UVB enhances the internalization of CLDN1. Transepidermal electrical resistance and paracellular flux of lucifer yellow, a fluorescent hydrophilic marker, were rescued by MDC. UVB changed neither the total nor phosphorylation levels of CLDN1, but it increased both mono-ubiquitination and tyrosine nitration levels of CLDN1. Fluorescence measurements revealed that UVB increased intracellular free Ca 2+ , nitric oxide (NO), and peroxynitrite contents, which were inhibited by Opsin2 (OPN2) siRNA, suggesting that OPN2 functions as a UVB sensor. The effects of UVB were inhibited by an antagonist of transient receptor potential type vanilloid 1 (TRPV1) and Ca 2+ chelator. Both NO donor and peroxynitrite donor induced the mislocalization of CLDN1 and disruption of TJ barrier, which were rescued by a NO synthase (NOS) inhibitor and a peroxynitrite scavenger. Weak UVB irradiation induced the disruption of TJ barrier mediated by mislocalization of CLDN1 in HaCaT cells. The OPN2/TRPV1/NOS signaling pathway may be a novel target for preventing destruction of the TJ barrier by UVB irradiation.

Plant responses to salinity have been extensively studied over the last decades. Despite the vast accumulated knowledge, the ways Arabidopsis lateral roots (LR) cope with lethal salinity has not been fully resolved. Here we compared the primary root (PR) and the LR responses during events leading to lethal salinity (NaCl 200 mM) in Arabidopsis. We found that the PR and young LR responded differently to lethal salinity: While the PR died, emerging and young LR's remained strikingly viable. Moreover, "age acquired salt tolerance" (AAST) was observed in the PR. During the 2 days after germination (DAG) the PR was highly sensitive, but at 8 DAG there was a significant increase in the PR cell survival. Nevertheless, the young LR exhibited an opposite pattern and completely lost its salinity tolerance, as it elongated beyond 400 µm. Examination of several cell death signatures investigated in the young LR showed no signs of an active programmed cell death (PCD) during lethal salinity. However, Autophagic PCD (A-PCD) but not apoptosis-like PCD (AL-PCD) was found to be activated in the PR during the high salinity conditions. We further found that salinity induced NADPH oxidase activated ROS, which were more highly distributed in the young LR compared to the PR, is required for the improved viability of the LR during lethal salinity conditions. Our data demonstrated a position-dependent resistance of Arabidopsis young LR to high salinity. This response can lead to identification of novel salt stress coping mechanisms needed by agriculture during the soil salinization challenge.

Because of the distinctive features of the oral cavity, the determination of the proteins involved in the formation of the "oral protein pellicle" is demanding. The present study investigated the susceptibility of several human basic proline-rich peptides, named P-H, P-D, P-F, P-J, and II-2, as substrates of transglutaminase-2. The reactivity of the P-C peptide and statherin was also investigated. Peptides purified from human whole saliva were incubated with the enzyme in the presence or in the absence of monodansyl-cadaverine. Mass spectrometry analyses of the reaction products highlighted that P-H and P-D (P 32 and A 32 variants) were active substrates, II-2 was less reactive, and P-F and P-J showed very low reactivity. P-C and statherin were highly reactive. All of the peptides formed cyclo derivatives, and only specific glutamine residues were involved in the cycle formation and reacted with monodansyl-cadaverine: Q 29 of P-H, Q 37 of P-D, Q 21 of II-2, Q 41 of P-C, and Q 37 of statherin were the principal reactive residues. One or two secondary glutamine residues of only P-H, P-D P 32 , P-C, and statherin were hierarchically susceptible to the reaction with monodansyl-cadaverine. MS and MS/MS data were deposited to the ProteomeXchange Consortium ( http://www.ebi.ac.uk/pride ) via the PRIDE partner repository with the data set identifier PXD014658.

Polyamines are involved in the regulation of many cellular functions and are promising biomarkers of numerous physiological conditions. Since the concentrations of these compounds in biological fluids are low, sample extraction is one of the most critical steps of their analysis. Here, we developed a comprehensive, sensitive, robust, and high-throughput LC-MS/MS stable-isotope dilution method for the simultaneous determination of 19 metabolites related to polyamine metabolism, including polyamines, acetylated and diacetylated polyamines, precursors, and catabolites from liquid biopsies. The sample extraction was optimized to remove interfering compounds and to reduce matrix effects, thus being useful for large clinical studies. The method consists of two-step liquid-liquid extraction with a Folch extraction and ethyl acetate partitioning combined with dansyl chloride derivatization. The developed method was applied to a small gender-related trial concerning human serum and urine samples from 40 obese subjects. Sex differences were found for cadaverine, putrescine, 1,3-diaminopropane, γ-aminobutyric acid, N8-acetylspermidine, and N-acetylcadaverine in urine; N1-acetylspermine in serum; and spermine in both serum and urine. The results demonstrate that the developed method can be used to analyze biological samples for the study of polyamine metabolism and its association with human diseases.

Cathepsin B plays key roles in tumor progression with its overexpression being associated with invasive and metastatic phenotypes and is a primary target of protease activated antibody-directed prodrug therapy. It therefore represents a potential therapeutic and diagnostic target and effort has been made to develop fluorescent probes to report on Cathepsin B activity in cells and animal models of cancer. We have designed, synthesized, and thoroughly evaluated four novel "turn on" probes that employ a lysosomotropic dansylcadaverine dye to report on Cathepsin B activity. Enzyme activity assays using a recombinant human enzyme and cancer cell lysates coupled with confocal microscopy experiments demonstrated that one of the probes, derivatized with the self-immolative prodrug linker p-aminobenzyl alcohol, can selectively report on Cathepsin B in biological samples including live cells., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Chikungunya virus (CHIKV) is a re-emerging arbovirus known to cause chronic myalgia and arthralgia with high morbidity. CHIKV is now considered endemic in many countries across Asia and Africa. In this study, the susceptibility of various human, mammalian and mosquito cell lines to CHIKV infection was evaluated. CHIKV infection was found to be cell-type dependent and virus strain-specific. Furthermore, SJCRH30 (human rhabdomyosarcoma cell line) was showed to be highly permissive to CHIKV infection, with maximum production of infectious virions observed at 12 h.p.i. Pre-infection treatment of SJCRH30 with various inhibitors of endocytosis, including monodansylcadaverine (receptor-mediated endocytic inhibitor), dynasore (clathrin-mediated endocytic inhibitor), as well as filipin (caveolin-mediated endocytosis inhibitor), resulted in minimal inhibition of CHIKV infection. In contrast, dose-dependent inhibition of CHIKV infection was observed with the treatment of macropinocytosis inhibitor, 5-(N-ethyl-N-isopropyl)amiloride (EIPA). Furthermore, siRNA-mediated knockdown of sortin nexin 9 (SNX9) a protein involved in macropinosome formation, also resulted in a significant dose-dependent reduction in viral titre. By performing a virus entry assay, CHIKV particles were also observed to colocalize with FITC-dextran, a macropinosome marker. This study shows for the first time, that the infectious entry of CHIKV into human muscle cells is mediated by macropinocytosis. Together, the data from this study may pave the way for the development of specific inhibitors that target the entry process of CHIKV into cells., Competing Interests: The authors have declared that no competing interests exist.

A high resolution accurate mass LC-MS method was developed to facilitate the characterization of a subset of antibody drug conjugate (ADC) biotherapeutics, where the payload is linked to the antibody by a thioether bond. Desulfuration of the thioether linker was optimized for release of the payload to take advantage of the high resolution and high mass accuracy of the Orbitrap to characterize metabolism of the payload. Two model ADCs, trastuzumab emtansine (T-DM1) and SigmaMAb dansyl-cadavarine-SMCC (SigmaMAb ADC mimic) were selected for optimization of the desulfuration reaction as a function of reaction time, pH, organic solvent, and chaotropic reagents (urea, guanidine HCl) by monitoring the yield of released desulfurated DM1 from T-DM1 and desulfurated dansyl-cadaverine-SMCC from SigmaMAb ADC mimic, respectively. The optimized desulfuration technique was successfully applied to enable characterization of the ADC following its incubation in hepatocytes, liver microsomes, and buffers, as illustrated by the identification of a hydrolyzed thiosuccinimide ring of SigmaMAb ADC mimic following incubation in buffer for 48 h. The results from this study demonstrate that the chemical cleavage of thioether bond by desulfuration is simple, efficient, and specific. This technique is useful in characterization of metabolism on the payload of ADC to provide guidance for improvement of its biopharmaceutical profile. This is the first report on characterization of modification to payload of ADC following desulfuration.

Inorganic phosphate (Pi) is often a limiting plant nutrient. In members of the Brassicaceae family, such as Arabidopsis ( Arabidopsis thaliana ), Pi deprivation reshapes root system architecture to favor topsoil foraging. It does so by inhibiting primary root extension and stimulating lateral root formation. Root growth inhibition from phosphate (Pi) deficiency is triggered by iron-stimulated, apoplastic reactive oxygen species generation and cell wall modifications, which impair cell-to-cell communication and meristem maintenance. These processes require LOW PHOSPHATE RESPONSE1 (LPR1), a cell wall-targeted ferroxidase, and PHOSPHATE DEFICIENCY RESPONSE2 (PDR2), the single endoplasmic reticulum (ER)-resident P5-type ATPase (AtP5A), which is thought to control LPR1 secretion or activity. Autophagy is a conserved process involving the vacuolar degradation of cellular components. While the function of autophagy is well established under nutrient starvation (C, N, or S), it remains to be explored under Pi deprivation. Because AtP5A/PDR2 likely functions in the ER stress response, we analyzed the effect of Pi limitation on autophagy. Our comparative study of mutants defective in the local Pi deficiency response, ER stress response, and autophagy demonstrated that ER stress-dependent autophagy is rapidly activated as part of the developmental root response to Pi limitation and requires the genetic PDR2-LPR1 module. We conclude that Pi-dependent activation of autophagy in the root apex is a consequence of local Pi sensing and the associated ER stress response, rather than a means for systemic recycling of the macronutrient., (© 2019 American Society of Plant Biologists. All Rights Reserved.)

Microbial transglutaminase (TGase) has been successfully used to produce site-specific protein conjugates derivatized at the level of glutamine (Gln) or lysine (Lys) residues with diverse applications. Here, we study the drug human interferon β-1a (IFN) as a substrate of TGase. The derivatization reaction was performed using carbobenzoxy-L-glutaminyl-glycine to modify Lys residues and dansylcadaverine for Gln residues. The 166 amino acids polypeptide chain of IFN β-1a contains 11 Lys and 11 Gln residues potential sites of TGase derivatization. By means of mass spectrometry analyses, we demonstrate the highly selective derivatization of this protein by TGase at the level of Lys115 and as secondary site at the level of Lys33, while no reactive Gln residue was detected. Limited proteolysis experiments were performed on IFN to determine flexible regions of the protein under physiological conditions. Interestingly, primary and secondary sites of limited proteolysis and of TGase derivatization occur at the same regions of the polypeptide chain, indicating that the extraordinary selectivity of the TGase-mediated reaction is dictated by the conformational features of the protein substrate. We envisage that the TGase-mediated derivatization of IFN can be used to produce interesting derivatives of this important therapeutic protein.

Objectives: Indium compounds are used in manufacturing displays of mobile phones and televisions. However, these materials cause interstitial pneumonia in exposed workers. Animal experiments demonstrated that indium compounds caused lung cancer. Chronic inflammation is considered to play a role in lung carcinogenesis and fibrosis induced by particulate matters. 8-Nitroguanine (8-nitroG) is a mutagenic DNA lesion formed during inflammation and may participate in carcinogenesis. To clarify the mechanism of carcinogenesis, we examined 8-nitroG formation in indium-exposed cultured cells., Methods: We treated RAW 264.7 mouse macrophages with indium oxide (In 2 O 3 ) nanoparticles (primary diameter: 30-50 nm), and performed fluorescent immunocytochemistry to detect 8-nitroG. The extent of 8-nitroG formation was evaluated by quantitative image analysis. We measured the amount of nitric oxide (NO) in the culture supernatant of In 2 O 3 -treated cells by the Griess method. We also examined the effects of inhibitors of inducible NO synthase (iNOS) and endocytosis on In 2 O 3 -induced 8-nitroG formation., Results: In 2 O 3 significantly increased the intensity of 8-nitroG formation in RAW 264.7 cells in a dose-dependent manner. In 2 O 3 -induced 8-nitroG formation was observed at 2 h and further increased at 4 h, and the amount of NO released from In 2 O 3 -exposed cells was significantly increased at 2-4 h compared with the control. 8-NitroG formation was suppressed by 1400W (an iNOS inhibitor), methyl-β-cyclodextrin and monodansylcadaverine (inhibitors of caveolae- and clathrin-mediated endocytosis, respectively)., Conclusions: These results suggest that endocytosis and NO generation participate in indium-induced 8-nitroG formation. NO released from indium-exposed inflammatory cells may induce DNA damage in adjacent lung epithelial cells and contribute to carcinogenesis.

The self-assembly of tyrosyl bolaamphiphiles is exploited to create a colloidal protein-like host matrix, upon which sacrificial electron-donor molecules associate to create a photosystem II (PSII) mimetic electron-relay system. This system harnesses the tyrosine phenol groups abundant on the surface of the assemblies to mediate photoinduced intermolecular electron transfer. Compared with the l-tyrosine molecules, the tyrosyl bolaamphiphile assembly facilitates electron transfer from the sacrificial electron donor to the oxidized photosensitizer. The enhanced electron relay is likely to be driven by the host function of the assembly associated with the sacrificial electron donor and by the suppression of the oxidative cross-linking of phenoxyl radicals. The tyrosyl bolaamphiphile assembly is advantageous in the construction of a PSII mimetic system with a protein-like nature and displaying biochemical functions., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Dysregulated autophagy is central to the pathogenesis and therapeutic development of cancer. However, how autophagy is regulated in cancer is not well understood and genes that modulate cancer autophagy are not fully defined. To gain more insights into autophagy regulation in cancer, we performed a large-scale RNA interference screen in K562 human chronic myeloid leukemia cells using monodansylcadaverine staining, an autophagy-detecting approach equivalent to immunoblotting of the autophagy marker LC3B or fluorescence microscopy of GFP-LC3B. By coupling monodansylcadaverine staining with fluorescence-activated cell sorting, we successfully isolated autophagic K562 cells where we identified 336 short hairpin RNAs. After candidate validation using Cyto-ID fluorescence spectrophotometry, LC3B immunoblotting, and quantitative RT-PCR, 82 genes were identified as autophagy-regulating genes. 20 genes have been reported previously and the remaining 62 candidates are novel autophagy mediators. Bioinformatic analyses revealed that most candidate genes were involved in molecular pathways regulating autophagy, rather than directly participating in the autophagy process. Further autophagy flux assays revealed that 57 autophagy-regulating genes suppressed autophagy initiation, whereas 21 candidates promoted autophagy maturation. Our RNA interference screen identifies identified genes that regulate autophagy at different stages, which helps decode autophagy regulation in cancer and offers novel avenues to develop autophagy-related therapies for cancer.

In this study, we present a targeted drug delivery system to improve intravesical therapy of bladder diseases. The drug delivery system consists of wheat germ agglutinin (WGA) to facilitate specific interaction with the surface of bladder cells and α-poly-(L)-glutamic acid (PGA) as polymeric backbone to increase the number of drug molecules per targeting moiety. Additionally, fluorescein cadaverine was coupled to PGA to visualise and track the delivery system. Using 5637 single cells and cell monolayers, the optimised F-PGA-WGA delivery system, with an approximate molecular weight of 670kDa, could convince with its promising cytoadhesive as well as cytoinvasive potential. Using the competitive inhibitor N, N', N″-triacetylchitotriose a specificity of the carbohydrate-mediated interaction between the cell and the delivery system of up to 98% was determined. F-PGA alone did not show any interaction with the cells. Moreover, a high drug loading of 77 molecules of the model drug Dansylcadaverine per backbone was achieved. Microscopic analysis further confirmed binding and uptake of the cytoadhesive polymer even after additional loading with the model drug. Combining the auspicious targeting properties of WGA with the high drug loading possibilities of the backbone might finally lead to an enhanced efficacy when used for intravesical therapy., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The insulin-like growth factor-1 receptor (IGF1R) mediates the biological actions of IGF1 and IGF2. The IGF1R is involved in both physiological and pathological activities and is usually overexpressed in most types of cancer. In addition to its classical mechanism of action, recent evidence has shown a nuclear presence of IGF1R, associated with novel genomic/transcriptional types of activities. The present study was aimed at evaluating the hypothesis that nuclear IGF1R localization is not restricted to cancer cells and might constitute a novel physiologically relevant regulatory mechanism. Our data shows that nuclear translocation takes place in a wide array of cells, including normal diploid fibroblasts. In addition, we provide evidence for a synergistic effect of a nuclear translocation blocker along with selective IGF1R inhibitors in terms of decreasing cell proliferation. Given the important role of the IGF1R in mitogenesis, the present results may be of translational relevance in cancer research. In conclusion, results are consistent with the concept that nuclear IGF1R fulfills important physiological and pathological roles.

Glioblastoma is the most common and lethal malignant primary brain tumor for which the development of efficacious chemotherapeutic agents remains an urgent need. The anti-helminthic drug niclosamide, which has long been in use to treat tapeworm infections, has recently attracted renewed interest due to its apparent anticancer effects in a variety of in vitro and in vivo cancer models. However, the mechanism(s) of action remains to be elucidated. In the present study, we found that niclosamide induced cell toxicity in human glioblastoma cells corresponding with increased protein ubiquitination, ER stress and autophagy. In addition, niclosamide treatment led to down-regulation of Wnt/β-catenin, PI3K/AKT, MAPK/ERK, and STAT3 pro-survival signal transduction pathways to further reduce U-87 MG cell viability. Taken together, these results provide new insights into the glioblastoma suppressive capabilities of niclosamide, showing that niclosamide can target multiple major cell signaling pathways simultaneously to effectively promote cell death in U-87 MG cells. Niclosamide constitutes a new prospect for a therapeutic treatment against human glioblastoma.

Ubiquitous polyamine spermidine is not required for normal planktonic growth of Bacillus subtilis but is essential for robust biofilm formation. However, the structural features of spermidine required for B. subtilis biofilm formation are unknown and so are the molecular mechanisms of spermidine-stimulated biofilm development. We report here that in a spermidine-deficient B. subtilis mutant, the structural analogue norspermidine, but not homospermidine, restored biofilm formation. Intracellular biosynthesis of another spermidine analogue, aminopropylcadaverine, from exogenously supplied homoagmatine also restored biofilm formation. The differential ability of C-methylated spermidine analogues to functionally replace spermidine in biofilm formation indicated that the aminopropyl moiety of spermidine is more sensitive to C -methylation, which it is essential for biofilm formation, but that the length and symmetry of the molecule is not critical. Transcriptomic analysis of a spermidine-depleted B. subtilis speD mutant uncovered a nitrogen-, methionine-, and S -adenosylmethionine-sufficiency response, resulting in repression of gene expression related to purine catabolism, methionine and S -adenosylmethionine biosynthesis and methionine salvage, and signs of altered membrane status. Consistent with the spermidine requirement in biofilm formation, single-cell analysis of this mutant indicated reduced expression of the operons for production of the exopolysaccharide and TasA protein biofilm matrix components and SinR antagonist slrR Deletion of sinR or ectopic expression of slrR in the spermidine-deficient Δ speD background restored biofilm formation, indicating that spermidine is required for expression of the biofilm regulator slrR Our results indicate that spermidine functions in biofilm development by activating transcription of the biofilm matrix exopolysaccharide and TasA operons through the regulator slrR ., (© 2017 by The American Society for Biochemistry and Molecular Biology, Inc.)

Autophagy is a degradative process by which eukaryotic cells digest their own components to provide aminoacids that may function as energy source under nutritional stress conditions. There is experimental evidence for autophagy in parasitic protists belonging to the family Trypanosomatidae. However, few proteins implicated in this process have been characterized so far in these parasites. Moreover, it has been shown that autophagy is involved in Trypanosoma cruzi differentiation and thus might have a role in pathogenicity. Here, we report the cloning and biochemical characterization of TcVps15. In addition, we demonstrate that TcVps15 interact with the PI3K TcVps34 and that both proteins associate with cellular membranes. Under nutritional stress conditions, TcVps15 and TcVps34 modify their subcellular distribution showing a partial co-localization in autophagosomes with TcAtg8.1 and using an active site TcVps15-mutated version (TcVps15-K219D-HA) we demonstrated that this relocalization depends on the TcVps15 catalytic activity. Overexpression of TcVps15-HA and TcVps15-K219D-HA also leads to increased accumulation of monodansylcadaverine (MDC) in autophagic vacuoles under nutritional stress conditions compared to wild-type cells. In addition, the MDC-specific activity shows to be significantly higher in TcVps15-HA overexpressing cells when compared with TcVps15-K219D-HA. Our results reveal for the first time a role of TcVps15 as a key regulator of TcVps34 enzymatic activity and implicate the TcVps15-Vps34 complex in autophagy in T. cruzi, exposing a new key pathway to explore novel chemotherapeutic targets., (© 2016 The Author(s) Journal of Eukaryotic Microbiology © 2016 International Society of Protistologists.)

In Drosophila , the final immune deficiency (IMD) pathway-dependent signal is transmitted through proteolytic conversion of the nuclear factor-κB (NF-κB)-like transcription factor Relish to the active N-terminal fragment Relish-N. Relish-N is then translocated from the cytosol into the nucleus for the expression of IMD-controlled genes. We previously demonstrated that transglutaminase (TG) suppresses the IMD pathway by polymerizing Relish-N to inhibit its nuclear translocation. Conversely, we also demonstrated that orally ingested synthetic amines, such as monodansylcadaverine (DCA) and biotin-labeled pentylamine, are TG-dependently incorporated into Relish-N, causing the nuclear translocation of modified Relish-N in gut epithelial cells. It remains unclear, however, whether polyamine-containing Relish-N retains transcriptional activity. Here, we used mass spectrometry analysis of a recombinant Relish-N modified with DCA by TG activity after proteolytic digestion and show that the DCA-modified Gln residues are located in the DNA-binding region of Relish-N. TG-catalyzed DCA incorporation inhibited binding of Relish-N to the Rel-responsive element in the NF-κB-binding DNA sequence. Subcellular fractionation of TG-expressing Drosophila S2 cells indicated that TG was localized in both the cytosol and nucleus. Of note, natural polyamines, including spermidine and spermine, competitively inhibited TG-dependent DCA incorporation into Relish-N. Moreover, in vivo experiments demonstrated that Relish-N was modified by spermine and that this modification reduced transcription of IMD pathway-controlled cecropin A1 and diptericin genes. These findings suggest that intracellular TG regulates Relish-N-mediated transcriptional activity by incorporating polyamines into Relish-N and via protein-protein cross-linking., (© 2017 by The American Society for Biochemistry and Molecular Biology, Inc.)

Tumor necrosis factor-alpha (TNF-α) exists in two forms: secretory TNF-α (sTNF-α) and transmembrane TNF-α (tmTNF-α). Although both forms of TNF-α induce tumor cell apoptosis, tmTNF-α is able to kill tumor cells that are resistant to sTNF-α-mediated cytotoxicity, indicating their differences in signal transduction. Here, we demonstrate that internalization of TNFR1 is crucial for sTNF-α- but not for tmTNF-α-induced apoptosis. sTNF-α induces binding of tumor necrosis factor receptor type 1-associated death domain protein (TRADD) to the death domain (DD) of TNFR1 and subsequent activation of nuclear factor kappa B (NF-κB), and the formation of death-inducing signaling complexes (DISCs) in the cytoplasm after internalization. In contrast, tmTNF-α induces DISC formation on the membrane in a DD-independent manner. It leads to the binding of signal transducer and activator of transcription 1 (STAT1) to a region spanning amino acids 319-337 of TNFR1 and induces phosphorylation of serine at 727 of STAT1. The phosphorylation of STAT1 promotes its binding to TRADD, and thus recruits Fas-associated protein with DD (FADD) and caspase 8 to form DISC complexes. This STAT1-dependent signaling results in apoptosis but not NF-κB activation. STAT1-deficiency in U3A cells counteracts tmTNF-α-induced DISC formation and apoptosis. Conversely, reconstitution of STAT1 expression restores tmTNF-α-induced apoptotic signaling in the cell line. Consistently, tmTNF-α suppresses the growth of STAT1-containing HT1080 tumors, but not of STAT1-deficient U3A tumors in vivo. Our data reveal an unappreciated molecular mechanism of tmTNF-α-induced apoptosis and may provide a new clue for cancer therapy.

Tissue transglutaminase (TGase 2) is the most abundantly expressed enzyme of the transglutaminase family and involved in a large variety of pathological processes, such as neurodegenerative diseases, disorders related to autoimmunity and inflammation as well as tumor growth, progression and metastasis. As a result, TGase 2 represents an attractive target for drug discovery and development, which requires assays that allow for the characterization of modulating agents and are appropriate for high-throughput screening. Herein, we report a fluorescence anisotropy-based approach for the determination of TGase 2's transamidase activity, following the time-dependent increase in fluorescence anisotropy due to the enzyme-catalyzed incorporation of fluorescein- and rhodamine B-conjugated cadaverines 1-3 (acyl acceptor substrates) into N,N-dimethylated casein (acyl donor substrate). These cadaverine derivatives 1-3 were obtained by solid-phase synthesis. To allow efficient conjugation of the rhodamine B moiety, different linkers providing secondary amine functions, such as sarcosyl and isonipecotyl, were introduced between the cadaverine and xanthenyl entities in compounds 2 and 3, respectively, with acyl acceptor 3 showing the most optimal substrate properties of the compounds investigated. The assay was validated for the search of both irreversible and reversible TGase 2 inhibitors using the inactivators iodoacetamide and a recently published L-lysine-derived acrylamide and the allosteric binder GTP, respectively. In addition, the fluorescence anisotropy-based method was proven to be suitable for high-throughput screening (Z' factor of 0.86) and represents a non-radioactive and highly sensitive assay for determining the active TGase 2 concentration.

Airway epithelial cell is often the initial site of attack by pathogens, and cell death is commonly caused by internalization of Mycobacterium tuberculosis ( Mtb ). However, the mechanism of interaction between epithelial cells and Mtb is not well understood. In this study, we investigated the role of the heparin-binding hemagglutinin (HBHA) protein of Mtb in the function of epithelial cells. In particular, the autophagy of A549 cells was determined based on microtubule-associated protein 1 light chain 3 alpha (LC3) activity. Autophagosome formation was detected by Monodansylcadaverine (MDC) staining and immune fluorescence staining of LC3. Autophagy could be significantly suppressed by HBHA protein. In addition, the LDH assay results showed that HBHA treatment could induce death on A549 cells. To explore the form of cell death, we detected the activity of caspase-3 and LDH release of A549 cells in the presence or absence of caspase inhibitor Z-VAD-FMK. Results demonstrated that HBHA treatment could induce apoptosis of A549 cells. To further confirm these results, we constructed the recombinant Mycobacterium smegmatis ( MS ) expressing HBHA ( rMS-HBHA ) and explored the influence of rMS-HBHA on the function of A549 cells. rMS-HBHA infection significantly inhibited LC3 expression and the maturation of autophagosomes in A549 cells. Subsequently, we infected A549 cells with MS and detected the viability of intracellular MS by CFU counts. rMS-HBHA showed higher survival and replication capacity in A549 cells than those of the wild-type MS . Finally, infection of A549 cells with rMS-HBHA caused further apoptosis. These findings suggested that rMS-HBHA could inhibit autophagy, promote its survival and replication within A549 cells, and subsequently induce apoptosis on infected cells to facilitate infection.

Autophagy, a ubiquitous intracellular degradation process, is conserved from yeasts to humans. It serves as a major survival function during nutrient depletion stress and is crucial for correct growth and differentiation. In this study, we characterized an atg1 orthologue Bcatg1 in the necrotrophic plant pathogen Botrytis cinerea. Quantitative real-time polymerase chain reaction (qRT-PCR) assays showed that the expression of BcATG1 was up-regulated under carbon or nitrogen starvation conditions. BcATG1 could functionally restore the survival defects of the yeast ATG1 mutant during nitrogen starvation. Deletion of BcATG1 (ΔBcatg1) inhibited autophagosome accumulation in the vacuoles of nitrogen-starved cells. ΔBcatg1 was dramatically impaired in vegetative growth, conidiation and sclerotial formation. In addition, most conidia of ΔBcatg1 lost the capacity to form the appressorium infection structure and failed to penetrate onion epidermis. Pathogenicity assays showed that the virulence of ΔBcatg1 on different host plant tissues was drastically impaired, which was consistent with its inability to form an appressorium. Moreover, lipid droplet accumulation was significantly reduced in the conidia of ΔBcatg1, but the glycerol content was increased. All of the defects of ΔBcatg1 were complemented by re-introduction of an intact copy of the wild-type BcATG1 into the mutant. These results indicate that BcATG1 plays a critical role in numerous developmental processes and is essential to the pathogenesis of B. cinerea., (© 2016 BSPP AND JOHN WILEY & SONS LTD.)

Autophagy is an intercellular degradation/recycling system by which cytoplasmic components are sequestered in autophagic vesicles (autophagosomes) and delivered to the vacuole for breakdown. During the last decade, plant studies have revealed that autophagy is employed as a major route to recycle nutrients needed for plant growth and development, and to combat with a wide range of biotic and abiotic stresses. Another important outcome of these studies was the development and optimization of methods and techniques for monitoring autophagy activity in plants. In this chapter, methods frequently used in plant autophagy study, from physiological to biochemical and microscopical analyses, are discussed.

Changes in the two main intracellular degradation systems, the Ubiquitin-Proteasome System and the Autophagy-Lysosome pathway (ALP) are widely discussed as a hallmark of the aging process. To follow the age-related behavior of both degradation systems we examined their impact on ferritin, known to be degradable by both. Ferritin H was analyzed in young and senescent human fibroblasts, revealing a higher steady-state level in the senescent cells. By blocking both proteolytic systems, we confirmed that particularly the ALP plays a crucial role in ferritin H turnover. However, an unexpected increase in lysosomal activity in the senescent cells, suggests a dysregulation in the autophagy pathway. To further investigate the impaired ferritin H turnover, confocal microscopic colocalization studies of ferritin H with lysosomal-associated membrane protein 2a (Lamp2a) and monodansylcadaverine (MDC) were performed and clearly revealed the degradation of ferritin by macroautophagy. By induction of autophagy via inhibition of mTOR using rapamycin an increase of ferritin H turnover was obtained in senescent cells, demonstrating a mTOR dependent reduction of autophagy in senescent human fibroblasts., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

Clearance of the apoptotic cells by phagocytes plays pivotal roles in maintenance of tissue homeostasis, promotion of immunological tolerance and anti-inflammatory response. Recent studies show that autophagy is involved in phagocytosis of the apoptotic cells. However, contribution of autophagy to phagocytosis of the apoptotic cells by macrophages is not clearly defined. Here, we assessed cytoprotective effect of autophagy on clearance of the apoptotic cells. Apoptosis of murine splenic lymphocytes and human T-cell leukemia cells was induced with cyclophosphamide. After engulfment of the apoptotic cells, expression of Belin-1 and LC3 in macrophages was upregulated, the number of MDC-positive vesicles, LC3-positive autophagosomes and autophagic ultrastructures increased significantly. Autophagosome was fused with phagosome containing fragments of the nuclei or other debris of the apoptotic cells to form amphisome. Some cells in macrophages phagocytosing the apoptotic cells became apoptotic. After autophagy of macrophages was inhibited with 3-MA, viability and survival of macrophages reduced, phagocytosis of the apoptotic cells by macrophages deceased significantly. These results demonstrate that autophagy plays an important role in promoting clearance of the apoptotic cells by protecting macrophages from apoptosis during phagocytosis as well as degrading the contents of phagosomes via amphisome formation., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background and Aims: Transglutaminase 2 (TGM2), a member of the transglutaminase family of enzymes, is a multifunctional protein involved in numerous events spanning from cell differentiation, to signal transduction, apoptosis, and wound healing. It is expressed in a variety of cells, macrophages included. Macrophage TGM2 promotes the clearance of apoptotic cells (efferocytosis) and emerging evidence suggests that defective efferocytosis contributes to the consequences of inflammation-associated diseases, including atherosclerotic lesion progression and its sequelae. Of interest, active TGM2 identified in human atherosclerotic lesions plays critical roles in plaque stability through effects on matrix cross-linking and TGFβ activity. This study explores the mechanisms by which TGM2 controls efferocytosis in human macrophages., Methods and Results: Herein we show that TGM2 increases progressively during monocyte differentiation towards macrophages and controls their efferocytic potential as well as morphology and viability. Two experimental approaches that took advantage of the inhibition of TGM2 activity and protein silencing give proof that TGM2 reduction significantly impairs macrophage efferocytosis. Among the mechanisms involved we highlighted a role of the receptors CD14 and SR-AI whose levels were markedly reduced by TGM2 inhibition. Conversely, CD36 receptor and αvβ3 integrin levels were not influenced. Of note, lipid accumulation and IL-10 secretion were reduced in macrophages displaying defective efferocytosis., Conclusion: Overall, our data define a crucial role of TGM2 activity during macrophage differentiation via mechanisms involving CD14 and SR-AI receptors and show that TGM2 inhibition triggers a pro-inflammatory phenotype., (Copyright © 2016 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

Background: Psoralidin (PSO), a natural phenolic coumarin, was reported to have anti-cancer activities. PSO induced reactive oxygen species (ROS) generation in cancer cells. The role of ROS in its anti-cancer effect remains unclear., Purpose: This study was designed to investigate the potential roles of ROS in PSO-induced anti-cancer effect in MCF-7 breast cancer cells., Methods: Effect of PSO on cancer cell proliferation was determined by MTT assay. Comet assay was used to determine DNA damage. Protein expression was detected by Western blotting. Autophagic vacuoles were detected by monodansylcadaverine (MDC) staining. ROS generation was measured by fluorescent probe. NOX4 localization was determined by immunofluorescence staining., Results: PSO treatment caused proliferation inhibition in time- and dose- dependent manners, which was partially reversed by N-acetyl cysteine (NAC) and diphenyleneiodonium (DPI). PSO induced DNA damage and increased protein expression of γ-H2AX, phosphorylation of ATM, ATR, Chk1, and Chk2. PSO induced autophagy as evidenced by the accumulation of autophagic vacuoles and alterations of autophagic protein expression. PSO-induced cell death was enhanced by autophagy inhibitor chloroquine (CQ). Furthermore, PSO treatment induced ROS formation, which was reversed by NAC or DPI pretreatment. The expression of NOX4 was significantly enhanced by PSO. Both NAC and DPI could reverse PSO-induced DNA damage and autophagic responses. In addition, silencing NOX4 by siRNA inhibited PSO-induced ROS generation, DNA damage, and autophagy., Conclusions: Taken together, these results showed that PSO induced DNA damage and protective autophagy mediated by ROS generation in a NOX4-dependent manner in MCF-7 cells., (Copyright © 2016 Elsevier GmbH. All rights reserved.)

The effects of spermidine analogues [norspermidine (NSPD, 33), spermidine (SPD, 34), homospermidine (HSPD, 44) and aminopropylcadaverine (APCAD, 35)] on cell growth were studied using Escherichia coli polyamine-requiring mutant MA261. Cell growth was compared at 32°C, 37°C, and 42°C. All four analogues were taken up mainly by the PotABCD spermidine-preferential uptake system. The degree of stimulation of cell growth at 32°C and 37°C was NSPD ≥ SPD ≥ HSPD > APCAD, and SPD ≥ HSPD ≥ NSPD > APCAD, respectively. However, at 42°C, it was HSPD » SPD > NSPD > APCAD. One reason for this is HSPD was taken up effectively compared with other triamines. In addition, since natural polyamines (triamines and teteraamines) interact mainly with RNA, and the structure of RNA is more flexible at higher temperatures, HSPD probably stabilized RNA more tightly at 42°C. We have thus far found that 20 kinds of protein syntheses are stimulated by polyamines at the translational level. Among them, synthesis of OppA, RpoE and StpA was more strongly stimulated by HSPD at 42°C than at 37°C. Stabilization of the initiation region of oppA and rpoE mRNA was tighter by HSPD at 42°C than 37°C determined by circular dichroism (CD). The degree of polyamine stimulation of OppA, RpoE and StpA synthesis by NSPD, SPD and APCAD was smaller than that by HSPD at 42°C. Thus, the degree of stimulation of cell growth by spermidine analogues at the different temperatures is dependent on the stimulation of protein synthesis by some components of the polyamine modulon.

Paracoccidioidomycosis (PCM), caused by Paracoccidioides species, is the main cause of death due to systemic mycoses in Brazil and other Latin American countries. Therapeutic options for PCM and other systemic mycoses are limited and time-consuming, and there are high rates of noncompliance, relapses, toxic side effects, and sequelae. Previous work has shown that the cyclopalladated 7a compound is effective in treating several kinds of cancer and parasitic Chagas disease without significant toxicity in animals. Here we show that cyclopalladated 7a inhibited the in vitro growth of Paracoccidioides lutzii Pb01 and P. brasiliensis isolates Pb18 (highly virulent), Pb2, Pb3, and Pb4 (less virulent) in a dose-response manner. Pb18 was the most resistant. Opportunistic Candida albicans and Cryptococcus neoformans were also sensitive. BALB/c mice showed significantly lighter lung fungal burdens when treated twice a day for 20 days with a low cyclopalladated 7a dose of 30 μg/ml/day for 30 days after intratracheal infection with Pb18. Electron microscopy images suggested that apoptosis- and autophagy-like mechanisms are involved in the fungal killing mechanism of cyclopalladated 7a. Pb18 yeast cells incubated with the 7a compound showed remarkable chromatin condensation, DNA degradation, superoxide anion production, and increased metacaspase activity suggestive of apoptosis. Autophagy-related killing mechanisms were suggested by increased autophagic vacuole numbers and acidification, as indicated by an increase in LysoTracker and monodansylcadaverine (MDC) staining in cyclopalladated 7a-treated Pb18 yeast cells. Considering that cyclopalladated 7a is highly tolerated in vivo and affects yeast fungal growth through general apoptosis- and autophagy-like mechanisms, it is a novel promising drug for the treatment of PCM and other mycoses., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

N-n-butyl haloperidol iodide (F2), a novel compound derived from haloperidol, protects against the damaging effects of ischemia/reperfusion (I/R) injury in vitro and in vivo. In this study, we hypothesized the myocardial protection of F2 on cardiomyocyte hypoxia/reoxygenation (H/R) injury is mediated by inhibiting autophagy in H9c2 cells. The degree of autophagy by treatment with F2 exposed to H/R in H9c2 cell was characterized by monodansylcadaverine, transmission electron microscopy, and expression of autophagy marker protein LC3. Our results indicated that treatment with F2 inhibited autophagy in H9c2 cells exposed to H/R. 3-methyladenine, an inhibitor of autophagy, suppressed H/R-induced autophagy, and decreased apoptosis, whereas rapamycin, a classical autophagy sensitizer, increased autophagy and apoptosis. Mechanistically, macrophage migration inhibitory factor (MIF) was inhibited by F2 treatment after H/R. Accordingly, small interfering RNA (siRNA)-mediated MIF knockdown decreased H/R-induced autophagy. In summary, F2 protects cardiomyocytes during H/R injury through suppressing autophagy activation. Our results provide a new mechanistic insight into a functional role of F2 against H/R-induced cardiomyocyte injury and death.

The polyamine spermidine is absolutely required for growth and cell proliferation in eukaryotes, due to its role in post-translational modification of essential translation elongation factor eIF5A, mediated by deoxyhypusine synthase. We have found that free-living ciliates Tetrahymena and Paramecium lost the eukaryotic genes encoding spermidine biosynthesis: S-adenosylmethionine decarboxylase (AdoMetDC) and spermidine synthase (SpdSyn). In Tetrahymena, they were replaced by a gene encoding a fusion protein of bacterial AdoMetDC and SpdSyn, present as three copies. In Paramecium, a bacterial homospermidine synthase replaced the eukaryotic genes. Individual AdoMetDC-SpdSyn fusion protein paralogues from Tetrahymena exhibit undetectable AdoMetDC activity; however, when two paralogous fusion proteins are mixed, AdoMetDC activity is restored and spermidine is synthesized. Structural modelling indicates a functional active site is reconstituted by sharing critical residues from two defective protomers across the heteromer interface. Paramecium was found to accumulate homospermidine, suggesting it replaces spermidine for growth. To test this concept, a budding yeast spermidine auxotrophic strain was found to grow almost normally with homospermidine instead of spermidine. Biosynthesis of spermidine analogue aminopropylcadaverine, but not exogenously provided norspermidine, correlated with some growth. Finally, we found that diverse single-celled eukaryotic parasites and multicellular metazoan Schistosoma worms have lost the spermidine biosynthetic pathway but retain deoxyhypusine synthase., (© 2015 John Wiley & Sons Ltd.)

Recent studies have suggested that cancer stem cells (CSCs) may be responsible for tumorigenesis and contribute to resistance to chemotherapy. Side population (SP) cells are thought to be enriched for CSCs in most types of human tumors. Therefore, the aim of the present study was to sort SP cells using an A549 lung cancer cell line, identify the cancer stem cell-like properties of SP and determine the role of autophagy in the survival of SP cells of lung cancer. SP cells were isolated by fluorescence-activated cell sorter (FACS) from A549 lung cancer cells, and the CSC-like properties were verified through confocal fluorescence imaging, sphere formation assays, cell proliferation and colony formation assay, gene expression in vitro and tumor formation in vivo. The role of autophagy in the survival of SP cells was assessed by western blotting and flow cytometric analysis. A549 lung cancer cells contained 1.10% SP cells. SP cells showed higher abilities of sphere and colony formation, cell proliferation and self-renewal. Moreover, compared to non-SP, SP cells demonstrated a higher mRNA expression of stem cell markers (MDR1, ABCG2 and OCT-4). The clone formation efficiency of SP cells was significantly higher than that non-SP cells under the same conditions. Expression of autophagosomes in SP cells was markedly lower than that in non-SP cells. However, the level of autophagy in SP cells was found to be markedly increased in the presence of cisplatin. In addition, inhibition of autophagy enhanced the effects of apoptosis induced by cisplatin. SP cells from the A549 lung cancer cell line possessed the properties of CSCs and were used to investigate the further characteristics of lung CSCs. SP cells were more resistant to chemotherapy and inhibition of autophagy enhanced the effects of apoptosis induced by the chemotherapeutic agent, cisplatin. These results may provide insight into novel therapeutic targets.

Autophagy plays an important role in response to intracellular and extracellular stress to sustain cell survival. However, dysregulated or excessive autophagy may lead to cell death, known as "type II programmed cell death," and it is closely associated with apoptosis. In our previous study, we proposed that olaquindox induced apoptosis of HepG2 cells through a caspase-9 dependent mitochondrial pathway. In this study, we investigated autophagy induced by olaquindox and explored the crosstalk between apoptosis and autophagy in olaquindox-treated HepG2 cells. Olaquindox-induced autophagy was demonstrated by the accumulation of monodansylcadervarine, as well as elevated expression of autophagy-related MAP-LC3 and Beclin 1 proteins. The autophagy inhibitor 3-methyladenine significantly increased the apoptotic rate induced by olaquindox, which was correlated with increased ratio of Bax/Bcl-2. The further studies showed that olaquindox increased the levels of reactive oxygen species (ROS), and antioxidant N-acetyl-L-cysteine (NAC) effectively blocked the accumulation of ROS but failed to block autophagy. Moreover, olaquindox induced the activation of c-Jun N-terminal protein kinase (JNK), and JNK inhibitor SP600125 failed to block autophagy. Instead, olaquindox-induced autophagy was enhanced by NAC or SP600125. Meanwhile, JNK activation was remarkably blocked by NAC, indicating that ROS may be the upstream signaling molecules of JNK activation and involved in the negative regulation of olaquindox-induced autophagy. These results suggest that olaquindox induces autophagy in HepG2 cells and that olaquindox-induced apoptosis can be enhanced by 3-methyladenine. Olaquindox-induced autophagy in HepG2 cells is upregulated by Beclin 1 but downregulated by ROS-dependent JNK., (Copyright © 2014 John Wiley & Sons, Ltd.)

Background: Ovarian cancer is the leading cause of death in women with gynecological malignancy worldwide. Despite multiple new approaches to treatment, relapse remains almost inevitable in patients with advanced disease. The poor outcome of advanced ovarian cancer treated with conventional therapy stimulated the search for new strategies to improve therapeutic efficacy. Although epidermal growth factor receptor (EGFR) and poly(ADP-ribose) polymerase (PARP) inhibitors have known activity in advanced ovarian cancer, the effect of combined therapy against EGFR and PARP in this population has not been reported. In the current study, we investigated the mechanisms of erlotinib used alone or in combination with olaparib (AZD2281), a potent inhibitor of PARP, in an EGFR-overexpressing ovarian tumor xenograft model., Methods: A2780 (EGFR-overexpressing, BRCA1/2 wild-type) cells were subcutaneously injected into nude mice, which were then randomly assigned to treatment with vehicle, erlotinib, AZD2281, or erlotinib + AZD2281, for up to 3 weeks. All mice were then sacrificed and tumor tissues were subjected to Western blot analysis and monodansylcadervarine staining (for analysis of autophagy)., Results: Erlotinib could slightly inhibit growth of A2780 tumor xenografts, and AZD2281 alone had similar effects on tumor growth. However, the combination treatment had a markedly enhanced antitumor effect. Western blot analysis revealed that treatment with erlotinib could significantly reduce the phosphorylation level of ERK1/2 and AKT in A2780 tumor tissue. Of interest, monodansylcadervarine staining showed that the autophagic effects were substantially enhanced when the agents were combined, which may be due to downregulation of apoptosis., Conclusion: These results suggest that combination of a selective EGFR inhibitor and a PARP inhibitor is effective in ovarian cancer A2780 xenografts, and depends on enhanced autophagy.

Low-dose ionizing radiation (LDIR) can induce radio-resistance to following high dose radiation in various mammalian cells. The protective role of LDIR has been thought to be associated with the overall outcomes of cancer radiotherapy. NF-E2 related factor 2 (Nrf2) is a transcription factor that plays pivotal roles in maintaining cellular oxidative equilibrium. Since oxidative stress has been indicated to be a mediator of LDIR induced radio-resistance, the role of Nrf2 in this process was investigated in this research. Our results showed that in human lung adenocarcinoma A549 cell, 5cGy alpha particle induced radio-resistance to following 75cGy alpha particle radiation. The expression level of Nrf2 and its target Heme Oxygenase-1(HO-1) increased after 5cGy radiation. Both the shRNA of Nrf2 and the chemical inhibitor of HO-1 suppressed the induced radio-resistance, indicating the involvement of Nrf2 antioxidant pathway in this process. Further, we found 5cGy radiation stimulated autophagy process in A549. Inhibition of the autophagy process resulted in suppression of the radio-resistance and the induced expression of Nrf2 and HO-1. ROS scavenger N-acetyl-L-cysteine (NAC) blocked the autophagy process induced by 5cGy alpha particle, the upregulation of Nrf2 and HO-1, as well as the induced radio-resistance. In conclusion, ROS elevation caused by LDIR promoted Autophagy/Nrf2-HO-1 and conferred radio-resistance in A549.

Autophagy is a common physiological process in cell homeostasis and regulation. Autophagy-related gene mutations and autophagy disorders are important in Crohn's disease (CD). The nucleotide oligomerization domain 2-autophagy genes autophagy 16-like 1 (NOD2-ATG16L1) signaling axis disorder contributes to the dysfunction of autophagy. This paper is focused on the relationship between contactin associated protein-like 3 (CNTNAP3) and ATG16L1 expression in Crohn's disease. The results indicated that the expression of ATG16L1 is higher in some CD patients compared to normal controls. ATG16L1 was well correlated with the C-reactive protein (CRP) in some CD patients. In vitro study revealed that CNTNAP3 could upregulate the expression of ATG16L1 and increase autophagy vacuoles.

Tissue transglutaminase 2 (TG2) is a multifunctional enzyme that cross-links proteins with monoamines such as serotonin (5-hydroxytryptamine, 5-HT) via a transglutamidation reaction, and is associated with pathophysiologic vascular responses. 5-HT is a mitogen for pulmonary artery smooth muscle cells (PASMCs) that has been linked to pulmonary vascular remodeling underlying pulmonary hypertension development. We previously reported that 5-HT-induced PASMC proliferation is inhibited by the TG2 inhibitor monodansylcadaverine (MDC); however, the mechanisms are poorly understood. In the present study we hypothesized that TG2 contributes to 5-HT-induced signaling pathways of PASMCs. Pre-treatment of bovine distal PASMCs with varying concentrations of the inhibitor MDC led to differential inhibition of 5-HT-stimulated AKT and ROCK activation, while p-P38 was unaffected. Concentration response studies showed significant inhibition of AKT activation at 50 μM MDC, along with inhibition of the AKT downstream targets mTOR, p-S6 kinase and p-S6. Furthermore, TG2 depletion by siRNA led to reduced 5-HT-induced AKT activation. Immunoprecipitation studies showed that 5-HT treatment led to increased levels of serotonylated AKT and increased TG2-AKT complex formations which were inhibited by MDC. Overexpression of TG2 point mutant cDNAs in PASMCs showed that the TG2 C277V transamidation mutant blunted 5-HT-induced AKT activation and 5-HT-induced PASMC mitogenesis. Finally, 5-HT-induced AKT activation was blunted in SERT genetic knock-out rat cells, but not in their wild-type counterpart. The SERT inhibitor imipramine similarly blocked AKT activation. These results indicate that TG2 contributes to 5-HT-induced distal PASMC proliferation via promotion of AKT signaling, likely via its serotonylation. Taken together, these results provide new insight into how TG2 may participate in vascular smooth muscle remodeling., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Although glucosamine has been suggested to be effective in the treatment of osteoarthritis, its effect on disc degeneration remains unclear. We sought to explore whether glucosamine can activate autophagy in rat nucleus pulposus (NP) cells and protect cells treated with IL-1β or hydrogen peroxide (H2 O2 ). Autophagy in cells was examined by detecting for LC3, Beclin-1, m-TOR, and p70S6K, as well as by analyzing autophagosomes. To inhibit autophagy, 3-methyladenine (3-MA) was used. In the cells treated with IL-1β, the levels of Adamts-4, Mmp-13, aggrecan, and Col2a1 were analyzed by real-time PCR and immunofluorescence. Apoptosis was analyzed by TUNEL. Cell senescence under H2 O2 was revealed by SA-β-Gal staining. Glucosamine could activate autophagy in a dose-dependent manner within 24 h and inhibit the phosphorylation of m-TOR and p70S6K. Autophagy in IL-1β or H2 O2 -treated cells was increased by glucosamine. Glucosamine attenuated the decrease of aggrecan and prevented the apoptosis of the NP cells induced by IL-1β, whereas 3-MA partly reversed these effects. The percentage of SA-β-Gal-positive cells induced by H2 O2 treatment was decreased by glucosamine, accompanied by the decline of p70S6K phosphorylation. Glucosamine protects NP cells and up-regulates autophagy by inhibiting the m-TOR pathway, which might point a potential therapeutic agent for disc degeneration., (© 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Polyamines (PAs) are low molecular weight aliphatic compounds that have been shown to be an important part of plant responses to salt stress. For that reason in this work we have investigated the involvement of PAs in the response to salt stress in root nodules of Phaseolus vulgaris in symbiosis with Rhizobium tropici. The level and variety of PAs was higher in nodules, compared to leaves and roots, and in addition to the common PAs (putrescine, spermidine and spermine) we found homospermidine (Homspd) as the most abundant polyamine in nodules. UPLC-mass spectrometry analysis revealed the presence of 4-aminobutylcadaverine (4-ABcad), only described in nodules of Vigna angularis before. Indeed, the analysis of different nodular fractions revealed higher level of 4-ABcad, as well as Homspd, in bacteroids which indicate the production of these PAs by the bacteria in symbiosis. The genes involved in PAs biosynthesis in nodules displayed an induction under salt stress conditions which was not consistent with the decline of free PAs levels, probably due to the nitrogen limitations provoked by the nitrogenase activity depletion and/or the conversion of free PAs to theirs soluble conjugated forms, that seems to be one of the mechanisms involved in the regulation of PAs levels. On the contrary, cadaverine (Cad) and 4-ABcad concentrations augmented by the salinity, which might be due to their involvement in the response of bacteroids to hyper-osmotic conditions. In conclusion, the results shown in this work suggest the alteration of the bacteroidal metabolism towards the production of uncommon PAs such as 4-ABcad in the response to salt stress in legume root nodules., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

In this article, edible hydrocolloid films were prepared by using Citrus pectins and the protein phaseolin in the presence of microbial transglutaminase, an enzyme able to catalyze isopeptide bonds between endo-protein-reactive glutamine and lysine residues. For the first time, trehalose, a nonreducing homodisaccharide into which two glucose units are linked together by a α-1,1-glycosidic linkage, was used as a component of hydrocolloid films constituted of both proteins and carbohydrates. Our data have demonstrated that these films act as very effective barriers to gases, especially to CO2 . They also present a high antioxidant capability as measured by the 2,2-diphenyl-1-picrylhydrazyl scavenging assay. In addition, the films were characterized using Atomic Force Microscopy, a powerful tool used to evaluate film surface topography and roughness. The results of our experiments clearly indicate that the trehalose-containing films prepared both in the presence and absence of transglutaminase are composed of nanoparticles with a smooth surface, having similar roughness values (Rα). In conclusion, according to barrier and antioxidant properties and to their structure, it is possible to consider the trehalose-containing films as innovative bioplastics potentially able to protect different kinds of foods., (© 2014 Wiley Periodicals, Inc.)

A new photoactivatable trifunctional cross-linker, cBED (cadaverine-2-[6-(biotinamido)-2-(p-azidobenzamido) hexanoamido]ethyl-1,3'-dithiopropionate), was synthesized by chemical conversion of sulfo-SBED (sulfosuccinimidyl-2-[6-(biotinamido)-2-(p-azidobenzamido) hexanoamido]ethyl-1,3'-dithiopropionate) with cadaverine. This cross-linker was purified by reversed-phase high-performance liquid chromatography (RP-HPLC) and characterized using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analysis. cBED is based on sulfo-SBED that has a photoactivatable azido group, a cleavable disulfide bond for label transfer methods, and a biotin moiety for highly sensitive biotin/avidin detection. By ultraviolet (UV) light, the azido group is converted to a reactive nitrene, transforming transient bindings of interacting structures to covalent bonds. In contrast to the sulfo-N-hydroxysuccinimide (sulfo-NHS) moiety of sulfo-SBED, which attaches quite unspecifically to amino groups, cBED includes a cadaverine moiety that can be attached by transglutaminase more specifically to certain glutamine residues. For instance, thymosin β4 can be labeled with cBED using tissue transglutaminase. By high-resolution HPLC/ESI-MS (electrospray ionization-mass spectrometry) and tandem MS (MS/MS) of the trypsin digest, it was established that glutamine residues at positions 23 and 36 were labeled, whereas Q39 showed no reactivity. The covalent binding of cBED to thymosin β4 did not influence its G-actin sequestering activity, and the complex could be used to identify new interaction partners. Therefore, cBED can be used to better understand the multifunctional role of thymosin β4 as well as of other proteins and peptides., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The receptor for advanced glycation end products (RAGE) is involved in diabetes or angiogenesis in tumors. Under pathological conditions, RAGE is overexpressed and upon ligand binding and internalization stimulates signaling pathways that promote cell proliferation. In this work, amino dendritic polymers PEI 25 kDa and alkylated derivatives of PAMAM-G2 were engineered by the nonenzymatic Maillard glycation reaction to generate novel AGE-containing gene delivery vectors targeting the RAGE. The glycated dendritic polymers were easily prepared and retained the capability to bind and protect DNA from endonucleases. Furthermore, while glycation decreased the transfection efficiency of the dendriplexes in CHO-k1 cells which do not express RAGE, glycated dendriplexes acted as efficient transfection reagents in CHO-k1 cells which stably express recombinant RAGE. In addition, preincubation with BSA-AGEs, a natural ligand of the RAGE, or dansyl cadaverine, an inhibitor of the RAGE internalization, blocked transfection, confirming their specificity toward RAGE. The results were confirmed in NRK and RAW264.7 cell lines, which naturally express the receptor. The glycated compounds retain their transfection efficiency in the presence of serum and promote in vivo transfection in a mouse model. Accordingly, RAGE is a suitable molecular target for the development of site-directed engineered glycated nonviral gene vectors.

The synthetic cannabinoid WIN 55,212-2 is a potent cannabinoid receptor agonist with anticancer potential. Experiments were performed to determine the effects of WIN on proliferation, cell cycle distribution, and programmed cell death in human osteosarcoma MG63 and Saos-2 cells. Results show that WIN induced G2/M cell cycle arrest, which was associated with the induction of the main markers of ER stress (GRP78, CHOP and TRB3). In treated cells we also observed the conversion of the cytosolic form of the autophagosome marker LC3-I into LC3-II (the lipidated form located on the autophagosome membrane) and the enhanced incorporation of monodansylcadaverine and acridine orange, two markers of the autophagic compartments such as autolysosomes. WIN also induced morphological effects in MG63 cells consisting in an increase in cell size and a marked cytoplasmic vacuolization. However, WIN effects were not associated with a canonical apoptotic pathway, as demonstrated by the absence of specific features, and only the addition of TRAIL to WIN-treated cells led to apoptotic death probably mediated by up-regulation of the tumor suppressor factor PAR-4, whose levels increased after WIN treatment, and by the translocation of GRP78 on cell surface.

Tissue transglutaminase (tTG) functions as a GTPase and an acyl transferase that catalyzes the formation of protein cross-links. tTG expression is frequently up-regulated in human cancer, where it has been implicated in various aspects of cancer progression, including cell survival and chemo-resistance. However, the extent to which tTG cooperates with other proteins within the context of a cancer cell, versus its intrinsic ability to confer transformed characteristics to cells, is poorly understood. To address this question, we asked what effect the ectopic expression of tTG in a non-transformed cellular background would have on the behavior of the cells. Using NIH3T3 fibroblasts stably expressing a Myc-tagged form of tTG, we found that tTG strongly protected these cells from serum starvation-induced apoptosis and triggered the activation of the PI3-kinase/mTOR Complex 1 (mTORC1)/p70 S6-kinase pathway. We determined that tTG forms a complex with the non-receptor tyrosine kinase c-Src and PI3-kinase, and that treating cells with inhibitors to block tTG function (monodansylcadaverine; MDC) or c-Src kinase activity (PP2) disrupted the formation of this complex, and prevented tTG from activating the PI3-kinase pathway. Moreover, treatment of fibroblasts over-expressing tTG with PP2, or with inhibitors that inactivate components of the PI3-kinase pathway, including PI3-kinase (LY294002) and mTORC1 (rapamycin), ablated the tTG-promoted survival of the cells. These findings demonstrate that tTG has an intrinsic capability to stimulate cell survival through a novel mechanism that activates PI3-kinase signaling events, thus highlighting tTG as a potential target for the treatment of human cancer.

Autophagy is a degradation pathway that recycles cell materials upon encountering stress conditions or during specific developmental processes. To better understand the physiological roles of autophagy, proper monitoring methods are very important. In mammals and yeast, monitoring of autophagy is often performed with a green fluorescent protein (GFP)-ATG8 fusion protein or with acidotropic dyes such as monodansylcadaverine (MDC) and LysoTracker Red (LTR). To evaluate these monitoring methods, here we examined these systems by inducing autophagy in Arabidopsis thaliana roots as a model for monitoring autophagy in planta. Under carbon- and nitrogen-starved conditions, the number and size of vesicles labeled by GFP-ATG8 was increased for several hours and then gradually decreased to a level higher than that observed before the start of the experiment. We also observed the disappearance of GFP-ATG8-labeled vesicles after treatment with wortmannin, a phosphatidylinositol 3-kinase inhibitor known as an autophagy inhibitor, showing that the GFP-ATG8 transgenic line constitutes an excellent method for monitoring autophagy. These data were compared with plants stained with MDC and LTR. There was no appreciable MDC/LTR staining of small organelles in the root under the induction of autophagy. Some vesicles were eventually observed in the root tip only, but co-localization experiments, as well as experiments with autophagy-deficient atg mutants, provided the evidence that these structures were located in the vacuole and were not manifestly autophagosomes and/or autolysosomes. Extreme caution should therefore be used when monitoring autophagy with the aid of MDC/LTR. Additionally, our observations strongly suggest that autophagosomes fuse directly to vacuoles in Arabidopsis roots.