Search Results (37)

ADP-ribosylation is a reversible modification of proteins and nucleic acids, which controls major cellular processes, including DNA damage repair, cell proliferation and differentiation, metabolism, stress, and immunity in plants and animals. The involvement of ADP-ribosylation in the life cycle of Dictyostelium and some filamentous fungi has also been demonstrated. However, the role of this process in pathogenic oomycetes has never been addressed. Here, we show that the Phytophthora infestans genome contains two PARP-like protein genes (PiPARP1 and PiPARP2), and provide evidence of PARylation activity for one of them (PiPARP2). Using dsRNA-mediated RNA silencing of the PiPARP2 gene and chemical (pharmacological) inhibition of PARP activity by 3-aminobenzamide (3AB) PARP inhibitor, we demonstrate the critical functional role of ADP-ribosylation in Phytophthora mycelium growth. Virulence test on detached leaves also suggests an important role of ADP-ribosylation in Phytophthora host plant colonisation and pathogenesis. On a practical level, our data suggest that targeting the PARylation system may constitute a novel powerful approach for the management of Phytophthora diseases. Full article

Background/Objectives: In addition to oncological applications, poly(ADP-ribose) polymerase (PARP) inhibitors have potential as anti-inflammatory agents. Colon-targeted delivery of PARP inhibitors has been evaluated as a pharmaceutical strategy to enhance their safety and therapeutic efficacy against gut inflammation. Methods: Colon-targeted PARP inhibitors 5-aminoisoquinoline (5-AIQ) and 3-aminobenzamide (3-AB) were designed and synthesized by azo coupling with salicylic acid (SA), yielding 5-AIQ azo-linked with SA (AQSA) and 3-AB azo-linked with SA (ABSA). Additional conjugation of AQSA with acidic amino acids yielded glutamic acid-conjugated AQSA (AQSA-Glu) and aspartic acid-conjugated AQSA, which further increased the hydrophilicity of AQSA. Results: The distribution coefficients of PARP inhibitors were lowered by chemical modifications, which correlated well with drug permeability via the Caco-2 cell monolayer. All derivatives were effectively converted to their corresponding PARP inhibitors in the cecal contents. Compared with observations in the oral administration of PARP inhibitors, AQSA-Glu and ABSA resulted in the accumulation of much greater amounts of each PARP inhibitor in the cecum. ABSA accumulated mesalazine (5-ASA) in the cecum to a similar extent as sulfasalazine (SSZ), a colon-targeted 5-ASA prodrug. In the DNBS-induced rat colitis model, AQSA-Glu enhanced the anticolitic potency of 5-AIQ. Furthermore, ABSA was more effective against rat colitis than SSZ or AQSA-Glu, and the anticolitic effects of AQSA-Glu were augmented by combined treatment with a colon-targeted 5-ASA prodrug. In addition, the colon-targeted delivery of PARP inhibitors substantially reduced their systemic absorption. Conclusions: Colon-targeted PARP inhibitors may improve the therapeutic and toxicological properties of inhibitors and synergize the anticolitic effects of 5-ASA. Full article

ADP-ribosylation (ADPRylation) is a mechanism which post-translationally modifies proteins in eukaryotes in order to regulate a broad range of biological processes including programmed cell death, cell signaling, DNA repair, and responses to biotic and abiotic stresses. Poly(ADP-ribosyl) polymerases (PARPs) play a key role in the process of ADPRylation, which modifies target proteins by attaching ADP-ribose molecules. Here, we investigated whether and how PARP1 and PARylation modulate responses of Nicotiana benthamiana plants to methyl viologen (MV)-induced oxidative stress. It was found that the burst of reactive oxygen species (ROS), cell death, and loss of tissue viability invoked by MV in N. benthamiana leaves was significantly delayed by both the RNA silencing of the PARP1 gene and by applying the pharmacological inhibitor 3-aminobenzamide (3AB) to inhibit PARylation activity. This in turn reduced the accumulation of PARylated proteins and significantly increased the gene expression of major ROS scavenging enzymes including SOD (NbMnSOD; mitochondrial manganese SOD), CAT (NbCAT2), GR (NbGR), and APX (NbAPX5), and inhibited cell death. This mechanism may be part of a broader network that regulates plant sensitivity to oxidative stress through various genetically programmed pathways. Full article

Photoprotective properties of 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) to reduce UV-induced DNA damage have been established in several studies. UV-induced DNA damage in skin such as single or double strand breaks is known to initiate several cellular mechanisms including activation of poly(ADP-ribose) (pADPr) polymerase-1 (PARP-1). DNA damage from UV also increases extracellular signal-related kinase (ERK) phosphorylation, which further increases PARP activity. PARP-1 functions by using cellular nicotinamide adenine dinucleotide (NAD+) to synthesise pADPr moieties and attach these to target proteins involved in DNA repair. Excessive PARP-1 activation following cellular stress such as UV irradiation may result in excessive levels of cellular pADPr. This can also have deleterious effects on cellular energy levels due to depletion of NAD+ to suboptimal levels. Since our previous work indicated that 1,25(OH)₂D₃ reduced UV-induced DNA damage in part through increased repair via increased energy availability, the current study investigated the effect of 1,25(OH)₂D₃ on UV-induced PARP-1 activity using a novel whole-cell enzyme- linked immunosorbent assay (ELISA) which quantified levels of the enzymatic product of PARP-1, pADPr. This whole cell assay used around 5000 cells per replicate measurement, which represents a 200–400-fold decrease in cell requirement compared to current commercial assays that measure in vitro pADPr levels. Using our assay, we observed that UV exposure significantly increased pADPr levels in human keratinocytes, while 1,25(OH)₂D₃ significantly reduced levels of UV-induced pADPr in primary human keratinocytes to a similar extent as a known PARP-1 inhibitor, 3-aminobenzamide (3AB). Further, both 1,25(OH)₂D₃ and 3AB as well as a peptide inhibitor of ERK-phosphorylation significantly reduced DNA damage in UV-exposed keratinocytes. The current findings support the proposal that reduction in pADPr levels may be critical for the function of 1,25(OH)₂D₃ in skin to reduce UV-induced DNA damage. Full article

This review article discusses the recent progress in synthesizing seven-membered ring 1,3,5-triazepine and benzo[f][1,3,5]triazepine derivatives. These derivatives can be either unsaturated, saturated, fused, or separated. This review covers strategies and procedures developed over the past two decades, including cyclo-condensation, cyclization, methylation, chlorination, alkylation, addition, cross-coupling, ring expansions, and ring-closing metathesis. This review discusses the synthesis of 1,3,5-triazepine derivatives using nucleophilic or electrophilic substitution reactions with various reagents such as o-phenylenediamine, 2-aminobenzamide, isothiocyanates, pyrazoles, thiazoles, oxadiazoles, oxadiazepines, and hydrazonoyl chloride. This article systematically presents new approaches and techniques for preparing these compounds. It also highlights the biological importance of benzo[f][1,3,5]triazepine derivatives, which have been used as drugs for treating nervous system diseases. This review aims to provide researchers with the necessary information to create and develop new derivatives of these compounds as quickly as possible. Full article

Recombinant human erythropoietin (EPO) is a biopharmaceutical frequently used in the treatment of anemia. It is a heavily glycosylated protein with a diverse and complex glycome. EPO N-glycosylation influences important pharmacological parameters, prominently serum half-life. Therefore, EPO N-glycosylation analysis is of the utmost importance in terms of controlling critical quality attributes. In this work, we performed an interlaboratory study of glycoanalytical techniques for profiling and in-depth characterization, namely (1) hydrophilic interaction liquid chromatography with fluorescence detection after 2-aminobenzamide labeling (HILIC-FLD(2AB)) and optional weak anion exchange chromatography (WAX) fractionation and exoglycosidase digestion, (2) HILIC-FLD after procainamide labeling (PROC) optionally coupled to electrospray ionization-MS and (3) matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-MS). All techniques showed good precision and were able to differentiate the unique N-glycosylation profiles of the various EPO preparations. HILIC-FLD showed higher precision, while MALDI-TOF-MS covered the most analytes. However, HILIC-FLD differentiated isomeric N-glycans, i.e., N-acetyllactosamine repeats and O-acetylation regioisomers. For routine profiling, HILIC-FLD methods are more accessible and cover isomerism in major structures, while MALDI-MS covers more minor analytes with an attractively high throughput. For in-depth characterization, MALDI-MS and HILIC-FLD(2AB)/WAX give a similar amount of orthogonal information. HILIC-FLD(PROC)-MS is attractive for covering isomerism of major structures with a significantly less extensive workflow compared to HILIC-FLD(2AB)/WAX. Full article

The centrosome is involved in cytoplasmic microtubule organization during interphase and in mitotic spindle assembly during cell division. Centrosome amplification (abnormal proliferation of centrosome number) has been observed in several types of cancer and in precancerous conditions. Therefore, it is important to elucidate the mechanism of centrosome amplification in order to understand the early stage of carcinogenesis. Primary cells could be used to better understand the early stage of carcinogenesis rather than immortalized cells, which tend to have various genetic and epigenetic changes. Previously, we demonstrated that a poly(ADP-ribose) polymerase (PARP) inhibitor, 3-aminobenzamide (3AB), which is known to be nontoxic and nonmutagenic, could induce centrosome amplification and chromosomal aneuploidy in CHO-K1 cells. In this study, we compared primary mouse embryonic fibroblasts (MEF) and immortalized MEF using 3AB. Although centrosome amplification was induced with 3AB treatment in immortalized MEF, a more potent PARP inhibitor, AG14361, was required for primary MEF. However, after centrosome amplification, neither 3AB in immortalized MEF nor AG14361 in primary MEF caused chromosomal aneuploidy, suggesting that further genetic and/or epigenetic change(s) are required to exhibit aneuploidy. The DNA-damaging agents doxorubicin and γ-irradiation can cause cancer and centrosome amplification in experimental animals. Although doxorubicin and γ-irradiation induced centrosome amplification and led to decreased p27Kip protein levels in immortalized MEF and primary MEF, the phosphorylation ratio of nucleophosmin (Thr199) increased in immortalized MEF, whereas it decreased in primary MEF. These results suggest that there exists a yet unidentified pathway, different from the nucleophosmin phosphorylation pathway, which can cause centrosome amplification in primary MEF. Full article

An iodine-mediated one-pot synthesis of pyrrolo/indolo [1,2-a]quinoxalines and quinazolin-4-one via utilizing epoxides as alkyl precursors under metal-free conditions has been described. Both 1-(2-aminophenyl)-pyrrole and 2-aminobenzamide could be applied to this protocol. A total of 33 desired products were obtained with moderate to good yields. This methodology was suitable for wide-scale preparation and the obtained products could be further modified into promising pharmaceutically active reagents. Full article

Polymeric optical films with light colors, good optical transparency and high thermal resistance have gained increasing attention in advanced optoelectronic areas in recent years. However, it is somewhat inter-conflicting for achieving the good optical properties to the conventional thermal resistant polymers, such as the standard aromatic polyimide (PI) films, which are well known for the excellent combined properties and also the deep colors. In this work, a series of wholly aromatic PI films were prepared via the polycondensation chemistry of one fluorene-containing dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (FDAn) and several aromatic diamines with amide linkages in the main chain, including 9,9-bis [4-(4-aminobenzamide)phenyl]fluorene (FDAADA), 2,2′-bis(trifluoromethyl)-4,4′-bis[4-(4-aminobenzamide)] biphenyl (ABTFMB), and 2,2′-bis(trifluoromethyl)-4,4′-bis[4-(4-amino-3-methyl)benzamide] biphenyl (MABTFMB). The derived FLPI-1 (FDAn-FDAADA), FLPI-2 (FDAn-ABTFMB) and FLPI-3 (FDAn-MABTFMB) resins showed good solubility in the polar aprotic solvents, such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc) and dimethyl sulfoxide (DMSO). The solution-processing FDAn-PI films exhibited good optical transmittance over 80.0% at a wavelength of 500 nm (T₅₀₀), yellow indices (b*) in the range of 1.01–5.20, and haze values lower than 1.0%. In addition, the FDAn-PI films showed low optical retardance with optical retardation (R_th) values in the range of 31.7–390.6 nm. At the same time, the FDAn-PI films exhibited extremely high glass transition temperatures (T_g) over 420 °C according to dynamic mechanical analysis (DMA) tests. The FDAn-PI films showed good dimensional stability at elevated temperatures with linear coefficients of thermal expansion (CTE) in the range of (31.8–45.8) × 10⁻⁶/K. Full article

An oxidant-free and highly efficient synthesis of phenolic quinazolin-4(3H)-ones was achieved by simply stirring a mixture of 2-aminobenzamides, sulfonyl azides, and terminal alkynes. The intermediate N-sulfonylketenimine underwent two nucleophilic additions and the sulfonyl group eliminated through the power of aromatization. The natural product 2-(4-hydroxybenzyl)quinazolin-4(3H)-one can be synthesized on a large scale under mild conditions with this method. Full article

Light-colored and transparent polyimide (PI) films with good high-temperature dimensional stability are highly desired for advanced optoelectronic applications. However, in practice, the simultaneous achievement of good optical and thermal properties in one PI film is usually difficult due to the inter-conflicting molecular design of the polymers. In the present work, a series of PI-SiO₂ nanocomposite films (ABTFCPI) were developed based on the PI matrix derived from hydrogenated pyromellitic anhydride (HPMDA) and an aromatic diamine containing benzanilide and trifluoromethyl substituents in the structure, 2,2′-bis(trifluoromethyl)-4,4′-bis [4-(4-aminobenzamide)]biphenyl (ABTFMB). The inorganic SiO₂ fillers were incorporated into the nanocomposite films in the form of colloidal nanoparticles dispersed in the good solvent of N,N-dimethylacetamide (DMAc) for the PI matrix. The derived ABTFCPI nanocomposite films showed good film-forming ability, flexible and tough nature, good optical transparency, and good thermal properties with loading amounts of SiO₂ up to 30 wt% in the system. The ABTFCPI-30 film with a SiO₂ content of 30 wt% in the film showed an optical transmittance of 79.6% at the wavelength of 400 nm (T₄₀₀) with a thickness of 25 μm, yellow index (b*) of 2.15, and 5% weight loss temperatures (T_5%) of 491 °C, which are all comparable to those the pristine ABTFCPI-0 matrix without filler (T₄₀₀ = 81.8%; b* = 1.77; T_5% = 492 °C). Meanwhile, the ABTFCPI-30 film exhibited obviously enhanced high-temperature dimensional stability with linear coefficients of thermal expansion (CTE) of 25.4 × 10⁻⁶/K in the temperature range of 50 to 250 °C, which is much lower than that of the AMTFCPI-0 film (CTE = 32.7 × 10⁻⁶/K). Full article

The nucleolus and Cajal bodies (CBs) are sub-nuclear domains with well-known roles in RNA metabolism and RNA-protein assembly. However, they also participate in other important aspects of cell functioning. This study uncovers a previously unrecognised mechanism by which these bodies and their components regulate host defences against pathogen attack. We show that the CB protein coilin interacts with poly(ADP-ribose) polymerase 1 (PARP1), redistributes it to the nucleolus and modifies its function, and that these events are accompanied by substantial increases in endogenous concentrations of salicylic acid (SA), activation of SA-responsive gene expression and callose deposition leading to the restriction of tobacco rattle virus (TRV) systemic infection. Consistent with this, we also find that treatment with SA subverts the negative effect of the pharmacological PARP inhibitor 3-aminobenzamide (3AB) on plant recovery from TRV infection. Our results suggest that PARP1 could act as a key molecular actuator in the regulatory network which integrates coilin activities as a stress sensor for virus infection and SA-mediated antivirus defence. Full article

N-(2-thioethyl)-2-aminobenzamide (TEAB), a novel glycan auxiliary, was synthesized and its utility was evaluated. The auxiliary was conjugated to glycans by reductive amination with the water-stable reagent 2-picoline borane complex. Glycan products, which ranged from 1 to 7 linked hexoses, were all isolated in yields ranging from 60% to 90% after purification by reverse-phase chromatography. The novel conjugate introduces a convenient, shelf-stable thiol directly onto the desired free glycans with purification advantages and direct modification with efficient reactions through alkenes, halides, epoxides, disulfides, and carboxylates in yields of 49% to 93%. Subsequently, a thiol-selective modification of the BSA protein was used to generate a neoglycoprotein with a bifunctional PEG–maleimide linker. To further illustrate the utility of a thiol motif, 2-thiopyridine activation of a thiol-containing support facilitated the covalent chromatographic purification of labeled glycans in yields up to 63%. Finally, initial proof of concept of implementation in a light printed microarray was explored and validated through FITC-labeled concanavalin A binding. In conclusion, the thiol-functionalized glycans produced greatly expand the diversity of bioconjugation tools that can be developed with glycans and enable a variety of biological investigations. Full article

Oligomeric proanthocyanidins (OPCs) are abundant polyphenols found in foods and botanicals that benefit human health, but our understanding of the functions of OPCs in rice plants is limited, particularly under cold stress. Two rice genotypes, named Zhongzao39 (ZZ39) and its recombinant inbred line RIL82, were subjected to cold stress. More damage was caused to RIL82 by cold stress than to ZZ39 plants. Transcriptome analysis suggested that OPCs were involved in regulating cold tolerance in the two genotypes. A greater increase in OPCs content was detected in ZZ39 than in RIL82 plants under cold stress compared to their respective controls. Exogenous OPCs alleviated cold damage of rice plants by increasing antioxidant capacity. ATPase activity was higher and poly (ADP-ribose) polymerase (PARP) activity was lower under cold stress in ZZ39 than in RIL82 plants. Importantly, improvements in cold tolerance were observed in plants treated with the OPCs and 3-aminobenzamide (PARP inhibitor, 3ab) combination compared to the seedling plants treated with H₂O, OPCs, or 3ab alone. Therefore, OPCs increased ATPase activity and inhibited PARP activity to provide sufficient energy for rice seedling plants to develop antioxidant capacity against cold stress. Full article

The design of proteolysis targeting chimeras (PROTACs) has become a promising technology for modifying a protein of interest (POI) through protein degradation. Herein, we describe the synthetic pathway to develop N⁴-(2-amino-4-fluorophenyl)-N¹-(3-{2-[2-(3-{[2-(2,6-dioxo-3-piperidyl)-1,3-dioxoisoindolin-4-yl]amino}propoxy)ethoxy]ethoxy}propyl)terephthalamide, which was designed to work as a selective degrader of histone deacetylase-3 (HDAC3). The newly synthesized compounds were characterized by ¹H-NMR, ¹³C-NMR, IR and HRMS. The title compound was tested in vitro against human class-I HDACs isoforms and showed IC₅₀ = 3.4 µM against HDAC3; however, it did not show degradation for the targeted HDACs. Full article