CSF total tau, Aβ42 and phosphorylated tau protein as biomarkers for Alzheimer’s disease

With the arrival of effective symptomatic treatments and the promise of drugs that may delay progression, we now need to identify Alzheimer’s disease (AD) at an early stage of the disease. To diagnose AD earlier and more accurately, attention has been directed toward peripheral biochemical markers. This article reviews promising potential cerebrospinal fluid (CSF) biomarkers for AD focussing on their role in clinical diagnosis. In particular, two biochemical markers, CSF total tau (t-tau) protein and the 42 amino acid form of β-amyloid (Aβ42), perform satisfactorily enough to achieve a role in the clinical diagnostic settings of patients with dementia together with the cumulative information from basic clinical work-up, genetic screening, and brain imaging. These CSF markers are particularly useful to discriminate early or incipient AD from age-associated memory impairment, depression, and some secondary dementias. In order to discriminate AD from other primary dementia disorders, however, more accurate and specific markers are needed. Preliminary evidence strongly suggests that quantification of tau phosphorylated at specific sites in CSF improves early detection, differential diagnosis, and tracking of disease progression in AD.     

Regulation of NF-κB signaling by oxidized glycerophospholipid and IL-1β induced miRs-21-3p and -27a-5p in human aortic endothelial cells

Exposure of endothelial cells (ECs) to agents such as oxidized glycerophospholipids (oxGPs) and cytokines, known to accumulate in atherosclerotic lesions, perturbs the expression of hundreds of genes in ECs involved in inflammatory and other biological processes. We hypothesized that microRNAs (miRNAs) are involved in regulating the inflammatory response in human aortic endothelial cells (HAECs) in response to oxGPs and interleukin 1β (IL-1β). Using next-generation sequencing and RT-quantitative PCR, we characterized the profile of expressed miRNAs in HAECs pre- and postexposure to oxGPs. Using this data, we identified miR-21-3p and miR-27a-5p to be induced 3- to 4-fold in response to oxGP and IL-1β treatment compared with control treatment. Transient overexpression of miR-21-3p and miR-27a-5p resulted in the downregulation of 1,253 genes with 922 genes overlapping between the two miRNAs. Gene Ontology functional enrichment analysis predicted that the two miRNAs were involved in the regulation of nuclear factor κB (NF-κB) signaling. Overexpression of these two miRNAs leads to changes in p65 nuclear translocation. Using 3′ untranslated region luciferase assay, we identified 20 genes within the NF-κB signaling cascade as putative targets of miRs-21-3p and -27a-5p, implicating these two miRNAs as modulators of NF-κB signaling in ECs.     

Synthesis of 3- and 21-monosulfates of [2,2,3β,4,4-²H₅]-tetrahydrocorticosteroids in the 5β-series as internal standards for mass spectrometry

The 3- and 21-monosulfates of pentadeuterated 5β-tetrahydrocorticosteroides were synthesized, starting from cortisol and 11-deoxycotisol. The principal reactions used were (1) perdeuteration of the methylene groups adjacent to the 3-oxo group of 17,20:20,21-bismethylendioxy-5β-3-ketosteroids with NaOD in CH₃OD followed by stereoselective reduction with NaBD₄, (2) sulfation of hydroxy groups with sulfur trioxide–trimethylamine complex, and (3) removal of the 17,20:20,21-bismethylendioxy group with hydrogen fluoride. The labeled compounds can be used as internal standards in liquid chromatography/mass spectrometry assays for clinical and biochemical studies.     

Evaluation of urinary 1-hydroxypyrene,S-phenylmercapturic acid,trans,trans-muconic acid, 3-methyladenine, 3-ethyladenine, 8-hydroxy-2′-deoxyguanosine and thioethers as biomarkers of exposure to cigarette smoke

The objective was to evaluate the utility of urinary 1-hydroxypyrene (1-OHP), S-phenylmercapturic acid (S-PMA), trans,trans-muconic acid (t,t-MA), 3-methyladenine (3-MeAd), 3-ethyladenine (3-EtAd), 8-hydroxy-2′-deoxyguanosine (8-OHdG) and thioethers as biomarkers for assessing the exposure in adult smokers who switched from smoking conventional cigarettes to candidate potential reduced exposure products (PREP) or who stopped smoking. Two electrically heated smoking systems (EHCSS) were used as prototype cigarettes that have significant reductions in a number of mainstream smoke constituents as measured by smoking machines relative to those from conventional cigarettes. Urine samples were collected from a randomized, controlled, forced-switching study in which 110 adult smokers of a conventional cigarette brand (CC1) were randomly assigned to five study groups. The groups included the CC1 smoking group, a lower-tar conventional cigarette (CC2) smoking group, EHCSS1 group, EHCSS2 group and a no smoking group that were monitored for 8 days. Biomarkers were measured at baseline and day 8. The daily excretion levels of these biomarkers were compared among the groups before and after switching, and the relationships between the daily excretion levels of these biomarkers and cigarette smoking-related exposure were investigated using Pearson product-moment correlation and multiple regression analyses. It was concluded that under controlled study conditions: (1) 1-OHP, S-PMA and t,t-MA are useful biomarkers that could differentiate exposure between smoking conventional and EHCSS cigarettes or between smoking conventional cigarettes and no smoking; between S-PMA and t,t-MA, the former appeared to be more sensitive; (2) 3-MeAd could only differentiate between smoking conventional cigarettes and no smoking; the results for 3-EtAd were not conclusive because contradictory results were observed; (3) 8-OHdG had a questionable association with smoking and therefore the utility of this biomarker for smoking-related exposure could not be established; and (4) urinary excretion of thioethers as a biomarker lacked sensitivity to demonstrate a clear dose–response relationship in conventional cigarette smokers, although it could differentiate the excretion levels between those subjects who smoked a conventional cigarette and those who stopped smoking.     

Design,synthesis and structure–activity relationship of novel quinoxalin-2-carboxamides as 5-HT3 receptor antagonists for the management of depression

A novel series of quinoxalin-2-carboxamides were designed based on the ligand-based approach, employing a three-point pharmacophore model; it consists of an aromatic residue and a linking carbonyl group and a basic nitrogen. The target new chemical entities were synthesized from the key intermediate, quinoxalin-2-carboxylic acid, by coupling it with various amines in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl) and 1-hydroxybenzotriazole (HOBt). The obtained compounds’ structures were confirmed by spectral data. The target new chemical entities were evaluated for their 5-HT₃ receptor antagonisms in longitudinal muscle myenteric plexus preparation from guinea pig ileum against 5-HT₃ agonist, 2-methyl-5-HT, which was expressed in the form of pA₂ value. All the synthesized compounds showed antagonism towards 5-HT₃ receptor; based on this result, a structure–activity relationship was derived, which reveals that the aromatic residue in 5-HT₃ receptor antagonists may have hydrophobic interaction with 5-HT₃ receptor. Regardless of their antagonistic potentials, all the synthesized molecules were screened for their anti-depressant potentials by using forced swim test in mice model; interestingly none of the tested compounds affect the locomotion of mice in the tested dose levels. Compounds with significant pA₂ values exhibited good anti-depressant-like activity as compared to the vehicle-treated group.     

Design,synthesis and evaluation of a novel metal chelator as multifunctional agents for the treatment of Alzheimer’s disease

A series of compounds following the lead compounds including deferasirox and tacrine were designed, synthesized and evaluated as multifunctional agents against Alzheimer’s disease (AD). In vitro studies showed that most synthesized compounds exhibited good multifunctional activities in inhibiting acetylcholinesterase (bAChE), and chelating metal ions. Especially, compound TD_e demonstrated significant metal chelating property, a moderate acetylcholinesterase (AChE) inhibitory activity and an antioxidant activity. Results from the molecular modeling indicated that TD compounds were mixed-type inhibitor, binding simultaneously to the catalytic anionic site (CAS) and the peripheral anionic site (PAS) of TcAChE. Moreover, TD_e showed a low cytotoxicity but a good protective activity against the injury caused by H₂O₂. These results suggest that TD compounds might be considered as attractive multi-target cholinesterase inhibitor and will play important roles in the treatment of AD.     

A novel multiplexed immunoassay identifies CEA,IL-8 and prolactin as prospective markers for Dukes’ stages A-D colorectal cancers

Background

Current methods widely deployed for colorectal cancers (CRC) screening lack the necessary sensitivity and specificity required for population-based early disease detection. Cancer-specific protein biomarkers are thought to be produced either by the tumor itself or other tissues in response to the presence of cancers or associated conditions. Equally, known examples of cancer protein biomarkers (e.g., PSA, CA125, CA19-9, CEA, AFP) are frequently found in plasma at very low concentration (pg/mL-ng/mL). New sensitive and specific assays are therefore urgently required to detect the disease at an early stage when prognosis is good following surgical resection. This study was designed to meet the longstanding unmet clinical need for earlier CRC detection by measuring plasma candidate biomarkers of cancer onset and progression in a clinical stage-specific manner. EDTA plasma samples (1 μL) obtained from 75 patients with Dukes’ staged CRC or unaffected controls (age and sex matched with stringent inclusion/exclusion criteria) were assayed for expression of 92 human proteins employing the Proseek® Multiplex Oncology I proximity extension assay. An identical set of plasma samples were analyzed utilizing the Bio-Plex Pro™ human cytokine 27-plex immunoassay.

Results

Similar quantitative expression patterns for 13 plasma antigens common to both platforms endorsed the potential efficacy of Proseek as an immune-based multiplex assay for proteomic biomarker research. Proseek found that expression of Carcinoembryonic Antigen (CEA), IL-8 and prolactin are significantly correlated with CRC stage.

Conclusions

CEA, IL-8 and prolactin expression were found to identify between control (unaffected), non-malignant (Dukes’ A + B) and malignant (Dukes’ C + D) stages.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-015-9081-x) contains supplementary material, which is available to authorized users.     

Design,synthesis and evaluation of pyrazolopyrimidinone derivatives as novel PDE9A inhibitors for treatment of Alzheimer’s disease

Phosphodiesterase-9 (PDE9) is a promising target for the treatment of Alzheimer’s disease (AD). To discover efficient PDE9 inhibitors with good metabolic stability and solubility, a series of novel pyrazolopyrimidinone derivatives have been designed with the assistance of molecular docking and dynamics simulations. All the fourteen synthesized compounds gave excellent inhibition ratio against PDE9 at 10 nM. Compound 1k with the IC₅₀ of 2.0 nM against PDE9, showed good metabolic stability (t_1/2 of 57 min) in the RLM as well as good solubility (195 mg/L). The analysis on binding modes of targeted compounds may provide insight for further structural modification.     

Echinoderm regenerative response as a sensitive ecotoxicological test for the exposure to endocrine disrupters: effects of p,p′DDE and CPA on crinoid arm regeneration

Echinoderms are valuable test species in marine ecotoxicology and offer a wide range of biological processes appropriate for this approach. Regenerating echinoderms can be regarded as amenable experimental models for testing the effects of exposure to contaminants, particularly endocrine disrupter compounds (EDCs). As regeneration is a typical developmental process, physiologically regulated by humoral mechanisms, it is highly susceptible to the action of pseudo-hormonal contaminants which appear to be obvious candidates for exerting deleterious actions. In our laboratory experiments, selected EDCs suspected for their antiandrogenic action (p,p′-DDE and cyproterone acetate) were tested at low concentrations on regenerating specimens of the crinoid Antedon mediterranea. An integrated approach which combines exposure experiments and different morphological analyses was employed; the obtained results suggest an overall pattern of plausible endocrine disruption in the exposed samples, showing that processes such as regenerative growth, histogenesis, and differentiation are affected by the exposure to the selected compounds. These results confirm that (1) regenerative phenomena of echinoderms can be considered valuable alternative models to assess the effects of exposure to exogenous substances such as EDCs, and (2) these compounds significantly interfere with fundamental processes of developmental physiology (proliferation, differentiation, etc…) plausibly via endocrine alterations. In terms of future prospects, taking into account the increasing need to propose animal models different from vertebrates, echinoderms represent a group on which ecotoxicological studies should be encouraged and specifically addressed.     

Design,synthesis and evaluation of novel cinnamic acid derivatives bearing N-benzyl pyridinium moiety as multifunctional cholinesterase inhibitors for Alzheimer’s disease

A novel family of cinnamic acid derivatives has been developed to be multifunctional cholinesterase inhibitors against AD by fusing N-benzyl pyridinium moiety and different substituted cinnamic acids. In vitro studies showed that most compounds were endowed with a noteworthy ability to inhibit cholinesterase, self-induced Aβ (1–42) aggregation, and to chelate metal ions. Especially, compound 5l showed potent cholinesterase inhibitory activity (IC₅₀, 12.1?nM for eeAChE, 8.6?nM for hAChE, 2.6?μM for eqBuChE and 4.4?μM for hBuChE) and the highest selectivity toward AChE over BuChE. It also showed good inhibition of Aβ (1–42) aggregation (64.7% at 20?μM) and good neuroprotection on PC12 cells against amyloid-induced cell toxicity. Finally, compound 5l could penetrate the BBB, as forecasted by the PAMPA-BBB assay and proved in OF1 mice by ex vivo experiments. Overall, compound 5l seems to be a promising lead compound for the treatment of Alzheimer’s diseases.     

Design,synthesis and biological evaluation of novel donepezil–coumarin hybrids as multi-target agents for the treatment of Alzheimer’s disease

Combining N-benzylpiperidine moiety of donepezil and coumarin into in a single molecule, novel hybrids with ChE and MAO-B inhibitory activity were designed and synthesized. The biological screening results indicated that most of compounds displayed potent inhibitory activity for AChE and BuChE, and clearly selective inhibition to MAO-B. Of these compounds, 5m was the most potent inhibitor for eeAChE and eqBuChE (0.87 μM and 0.93 μM, respectively), and it was also a good and balanced inhibitor to hChEs and hMAO-B (1.37 μM for hAChE; 1.98 μM for hBuChE; 2.62 μM for hMAO-B). Molecular modeling and kinetic studies revealed that 5m was a mixed-type inhibitor, which bond simultaneously to CAS, PAS and mid-gorge site of AChE, and it was also a competitive inhibitor, which occupied the active site of MAO-B. In addition, 5m showed good ability to cross the BBB and had no toxicity on SH-SY5Y neuroblastoma cells. Collectively, all these results suggested that 5m might be a promising multi-target lead candidate worthy of further pursuit.     

Structure and Conformation of the Branch Core Triribonucleotide Containing 2′-5′ and 3′-5′ Phosphodiester Linkages (A2′p5′G 3′p5′C) in Solution,Essential for Yeast mRNA Splicing,Deduced from 1H-NMR

Abstract

The non-exchangeable ¹H-NMR signals of the branch core trinucleotide of the lariat branch site (A^2′p5′G _3′p5′C), 1) and its derivatives 2 and 3 are completely assigned using one- and two- dimensional NMR techniques including NOE, COSY, NOESY, ¹H-¹HINADEQUATE and 2D-J-resolved spectroscopy. From the vicinal coupling constants in the individual ribose rings, NOE data and T₁ measurements, the following properties of the trimers are deduced.(i)The unique stacking behavior of the trimers is S^1′N _3′N, and the sugar rings exist predominantly in the N-conformation (3′-endo-2′-exo).(ii)The sugar-base orientations appear to be anti.(iii) The branched trimers exist in solution as single-stranded right-handed conformations resembling A-RNA with stacking between the adenine and guanine residues in aqueous solution at 21°C and pH 7.2.(iv) The calculated values for the torsion angles ε^t andγ⁺ for the trimers are 201–203° and 71–86%, respectively, while the percent β¹ values are higher for the guanine (87–92%) than the cytosine residues (73–77%). The computer generated depiction of the triribonucleotide 1 is also shown. These subtle structural features may act as recognition signals for this critical lariat branch site which is essential for the second step in yeast mRNA splicing.     

DL-3-n-butylphthalide-Edaravone hybrids as novel dual inhibitors of amyloid-β aggregation and monoamine oxidases with high antioxidant potency for Alzheimer’s therapy

Considering the complex etiology of Alzheimer’s disease (AD), multifunctional agents may be beneficial for the treatment of this disease. A series of DL-3-n-butylphthalide-Edaravone hybrids were designed, synthesized and evaluated as novel dual inhibitors of amyloid-β aggregation and monoamine oxidases. Among them, compounds 9a–d exhibited good inhibition of self-induced Aβ_1-42 aggregation with inhibition ratio 57.7–71.5%. For MAO, these new hybrids exhibited good balance of inhibition for MAO-A and MAO-B. In addition, all target compounds retained the antioxidant activity of edaravone, showed equal or better antioxidant activity than edaravone. The results of the parallel artificial membrane permeability assay for blood-brain barrier indicated that compounds 9a–d would be able to cross the blood-brain barrier and reach their biological targets in the central nervous system. The promising results in all assays demonstrated that the strategy behind the designing of compounds was rational and favourable. Taken together, these preliminary findings suggested that the compounds with the strongest bioactivity deserves further investigated for pharmacological development in AD therapy.     

A class of novel Schiff’s bases: Synthesis,therapeutic action for chronic pain,anti-inflammation and 3D QSAR analysis

To discover analgesics for treating chronic pain 17 novel Schiff’s bases, N,N′-(Z-allylidene-1,3-diyl)bisamino acid methyl esters were prepared from 1,1,3,3,-tetramethoxypropane and amino acid methyl esters. On tail-flick mouse model 20 μmol/kg of these Schiff’s bases were orally administered, the analgesic action started 30 min after administration, reached the maximum 120 min after administration, and at 180 min this action was still observed. On a xylene-induced ear edema mouse model 20 μmol/kg of these Schiff’s bases exhibited desirable anti-inflammation. Thus the present Schiff’s bases are able to treat chronic pain from inflammation. The effect of the side chains of the amino acid residues of these Schiff’s bases on the analgesic activity was explained with 3D QSAR.     

Design,synthesis and biological evaluation of novel 3-oxo-4-oxa-5α-androst-17β-amide derivatives as dual 5α-reductase inhibitors and androgen receptor antagonists

Prostate cancer (PCa) is the second leading cause of death in men. Recently, some researches have showed that 5α-reductase inhibitors were beneficial in PCa treatment as well. In this study, a series of novel 3-oxo-4-oxa-5α-androst-17β-amide derivatives have been designed and synthesized in a more simple and convenient method. Most of the synthesized compounds displayed good 5α-reductase inhibitory activities and androgen receptor binding affinities. Their anti-proliferation activities in PC-3 and LNCaP cell lines were also evaluated and the results indicated that most of the synthesized compounds exhibited potent anti-proliferative activities. It is obvious that the androgen-dependent cell line LNCaP was much more sensitive than the androgen-independent cell line PC-3. Among all the synthesized compounds, 11d and 11k displayed the best inhibition activity with 4-fold more sensitive toward LNCaP than PC-3, which was consistent with their high affinities observed in AR binding assay. Molecular modeling studies suggested that 11k could bind to AR in a manner similar to the binding of dihydrotestosterone to AR. Compared to the finasteride, 11k showed a longer plasma half-life (4 h) and a better bioavailability. Overall, based on biological activities data, compound 11d and 11k can be identified as potential dual 5α-reductase inhibitors and AR antagonists which might be of therapeutic importance for prostate cancer treatment.     

Design,synthesis and evaluation of novel tacrine-(β-carboline) hybrids as multifunctional agents for the treatment of Alzheimer’s disease

A series of tacrine-(β-carboline) hybrids (11a–q) were designed, synthesized and evaluated as multifunctional cholinesterase inhibitors against Alzheimer’s disease (AD). In vitro studies showed that most of them exhibited significant potency to inhibit acetylcholinesterase (eeAChE and hAChE), butyrylcholinesterase (BuChE) and self-induced β-amyloid (Aβ) aggregation, Cu²⁺-induced Aβ (1–42) aggregation, and to chelate metal ions. Especially, 11l presented the greatest ability to inhibit cholinesterase (IC₅₀, 21.6 nM for eeAChE, 63.2 nM for hAChE and 39.8 nM for BuChE), good inhibition of Aβ aggregation (65.8% at 20 μM) and good antioxidant activity (1.57 trolox equivalents). Kinetic and molecular modeling studies indicated that 11l was a mixed-type inhibitor, binding simultaneously to the catalytic anionic site (CAS) and the peripheral anionic site (PAS) of AChE. In addition, 11l could chelate metal ions, reduce PC12 cells death induced by oxidative stress and penetrate the blood–brain barrier (BBB). These results suggested that 11l might be an excellent multifunctional agent for AD treatment.     

Design,synthesis and biological evaluation of novel 3-substituted pyrazolopyrimidine derivatives as potent Bruton’s tyrosine kinase (BTK) inhibitors

A series of 3-substituted pyrazolopyrimidine derivatives as BTK inhibitors were designed by structure-based drug design and they were synthesized, evaluated by enzyme-based assay and anti-proliferation against Ramos and Raji cells. Most of them displayed good inhibitory activities against both BTK and B-cell lymphoblastic leukemia lines in vitro. Among them, compound 8a exhibited excellent potency (IC₅₀?=?7.95?nM against BTK enzyme, 8.91?μM against Ramos cells and 1.80?μM against Raji cells), with a better hydrophilicity (ClogP?=?3.33). These explorations provided new clues to discover 3-substituted pyrazolopyrimidine derivatives as novel anti-tumor agents.     

Design, synthesis and biological assessment of novel N-substituted 3-(phthalimidin-2-yl)-2,6-dioxopiperidines and 3-substituted 2,6-dioxopiperidines for TNF-α inhibitory activity

Eight novel 2-(2,6-dioxopiperidin-3-yl)phthalimidine EM-12 dithiocarbamates 9 and 10, N-substituted 3-(phthalimidin-2-yl)-2,6-dioxopiperidines 11-14 and 3-substituted 2,6-dioxopiperidines 16 and 18 were synthesized as tumor necrosis factor-α (TNF-α) synthesis inhibitors. Synthesis involved utilization of a novel condensation approach, a one-pot reaction involving addition, iminium rearrangement and elimination, to generate the phthalimidine ring required for the creation of compounds 9-14. Agents were, thereafter, quantitatively assessed for their ability to suppress the synthesis on TNF-α in a lipopolysaccharide (LPS)-challenged mouse macrophage-like cellular screen, utilizing cultured RAW 264.7 cells. Whereas compounds 9, 14 and 16 exhibited potent TNF-α lowering activity, reducing TNF-α by up to 48% at 30 μM, compounds 12, 17 and 18 presented moderate TNF-α inhibitory action. The TNF-α lowering properties of these analogs proved more potent than that of revlimid (3) and thalidomide (1). In particular, N-dithiophthalimidomethyl-3-(phthalimidin-2-yl)-2,6-dioxopiperidine 14 not only possessed the greatest potency of the analogs to reduce TNF-α synthesis, but achieved this with minor cellular toxicity at 30 μM. The pharmacological focus of the presented compounds is towards the development of well-tolerated agents to ameliorate the neuroinflammation, that is, commonly associated with neurodegenerative disorders, epitomized by Alzheimer's disease and Parkinson's disease.     

Identification of 4′-O-β-d-glucosyl-5-O-methylvisamminol as a novel epigenetic suppressor of histone H3 phosphorylation at Ser10 and its interaction with 14-3-3ε

Natural compounds are regarded as a rich source for potential anti-inflammatory and anti-carcinogenic agents. Increasing evidence indicates that histone phosphorylation at Ser10 is a marker for cell cycle progression during the mitosis and the induction of immediate pro-inflammatory genes during the interphase. In the present study, we have screened our in-house natural compounds to find out new chemical inhibitor(s) of histone H3 phosphorylation at Ser10. As a result, we observed that α-amyrin, oleanolic acid, marliolide, and 4′-O-β-d-glucosyl-5-O-methylvisamminol decreased the levels of histone H3 phosphorylation at Ser10 and c-Jun. In particular, we observed that 4′-O-β-d-glucosyl-5-O-methylvisamminol suppressed the direct interaction of histone H3 with 14-3-3ε, inhibited the aurora B kinase activity and delayed the mitotic cell cycle progression. We reports 4′-O-β-d-glucosyl-5-O-methylvisamminol as the first epigenetic natural chemical inhibitor that can abrogates the mitotic cell cycle progression and immediate pro-inflammatory gene expressions via suppression of histone H3 phosphorylation at Ser10 and its interaction with 14-3-3ε.