Development and evolution of human glutaminyl cyclase inhibitors (QCIs): an alternative promising approach for disease-modifying treatment of Alzheimer's disease.

Human glutaminyl cyclase (hQC) is drawing considerable attention and emerging as a potential druggable target for Alzheimer's disease (AD) due to its close involvement in the pathology of AD via the post-translational pyroglutamate modification of amyloid-ß. A recent phase 2a study has shown promising early evidence of efficacy for AD with a competitive benzimidazole-based QC inhibitor, PQ912, which also demonstrated favorable safety profiles. This finding has sparked new hope for the treatment of AD. In this review, we briefly summarize the discovery and evolution of hQC inhibitors, with a particular interest in classic Zinc binding group (ZBG)-containing chemicals reported in recent years. Additionally, we highlight several high-potency inhibitors and discuss new trends and challenges in the development of QC inhibitors as an alternative and promising disease-modifying therapy for AD.

Co-inducible Catabolism of 2-Naphthol Initiated by Hydroxylase CehC1C2 in Rhizobium sp. X9 Removed Its Ecotoxicity.

2-Naphthol, which originates from various industrial activities, is widely disseminated through the discharge of industrial wastewater and is, thus, harmful to the water ecosystem, agricultural production, and human health. In this study, the carbaryl degrading strain Rhizobium sp. X9 was proven to be able to degrade 2-naphthol and reduce its toxicity to rice (Oryza sativa) and Chlorella ellipsoidea. Two-component hydroxylase CehC1C2 is responsible for the initial step of degradation and generates 1,2-dihydroxynaphthalene, which is further degraded by the ceh cluster. The transcription of gene cluster cehC1C2 could be induced when both 2-naphthol and glucose were added. A bioinformatic analysis revealed that two transcriptional regulators, the inhibitor CehR2 and the activator CehR3, could be involved in this process. Our study elucidated the molecular mechanism of microbial degradation of 2-naphthol and provided an effective strategy for the in situ remediation of 2-naphthol contamination in the environment.

Rotor-Tuning Boron Dipyrromethenes for Dual-Functional Imaging of Aß Oligomers and Viscosity.

Alzheimer's disease (AD), known as a common incurable and elderly neurodegenerative disease, has been widely explored for accurate detection of its biomarker (Aß oligomers) for early diagnosis. Although great efforts have been made, it is still of great importance to develop fluorescence probes for Aß oligomers with good selectivity and low background. Herein, starting from BODIPY493/503 (a commercial dye for neutral lipid droplets), which exhibited a small Stokes shift and no response toward Aß peptides, two fluorescence probes 5MB-SZ and B-SZ with a benzothiazole rotor at the 2-position of the BODIPY core and a methyl or benzyl group at the meso position have been designed and synthesized, which exhibited excellent optical properties/stability and could successfully image ß-amyloid fibrils and viscosity. Upon exposure to Aß oligomers, the fluorescence intensity of 5MB-SZ was enhanced by 43.64-fold with the corresponding fluorescence quantum yields changing from 0.85% to 27.43%. Meanwhile, probe 5MB-SZ showed a highly sensitive viscosity response in both solutions and living cells. In vitro and in vivo experiments confirmed that probe 5MB-SZ exhibited an excellent capacity for imaging ß-amyloid fibrils. Therefore, 5MB-SZ, as a rotor-tuning BODIPY analogue, could possibly serve as a highly potential and powerful fluorescence probe for early diagnosis of AD.

Possible causes of atherosclerosis: lncRNA COLCA1 induces oxidative stress in human coronary artery endothelial cells and impairs wound healing.

Background: Atherosclerosis is the most common cause of cardiovascular disease, accompanied by high mortality and poor prognosis. Low-density lipoprotein (LDL) and its oxidized form oxidized low-density lipoprotein (oxLDL) play an important role in atherosclerosis. This article will explore the role of the lncRNA COLCA1 (colorectal cancer associated 1)/hsa-miR-371a-5p/SPP1 (secreted phosphoprotein 1) pathway in oxLDL in causing human coronary artery endothelial cells (HCAECs) inflammation and related biological function changes. Methods: OxLDL was used to stimulate HCAECs. The inflammatory response and biological function changes of HCAECs were analyzed, total RNA-seq was performed on HCAECs before and after stimulation, and RT-Qpcr (real-time quantitative PCR) was used to verify the differential genes. Interference of the expression of COLCA1 in HCAECs was performed by siRNA interference technology to verify the role of COLCA1 in the biological function changes of HCAECs after oxLDL stimulation, and further prove that COLCA1 affects SPP1 through hsa-miR-371a-5p. Results: OxLDL can affect the oxidative stress response of HCAECs, which in turn affects the apoptosis and wound healing ability of HCAECs. COLCA1 and SPP1 were highly expressed after oxLDL stimulation, while hsa-miR-371a-5p was the opposite. After COLCA1 interference, the oxidative stress level of HCAECs stimulated by oxLDL decreased, the apoptosis level also significantly decreased, and the wound healing ability was enhanced. After simultaneous COLCA1 interference and recovery of the expression of hsa-miR-371a-5p, these improved functions disappeared. The dual-luciferase assay confirmed that hsa-miR-371a-5p and COLCA1, hsa-miR-371a-5p and SPP1 has binding targets. Conclusions: OxLDL can up-regulate the expression of COLCA1 in HCAECs, which in turn affects the intracellular COLCA1/hsa-miR-371a-5p/SPP1 pathway to regulate the level of oxidative stress in cells. This in turn affects the level of apoptosis and wound healing ability, which causes cells to produce a continuous inflammatory response.

METTL3-mediated M6A methylation modification is involved in colistin-induced nephrotoxicity through apoptosis mediated by Keap1/Nrf2 signaling pathway.

Colistin is a cationic polypeptide antibiotic. Despite its nephrotoxicity, it is still widely used as a last-line antibiotic against infection worldwide with the emergence of multi-drug resistant Gram-negative bacilli. N-methyladenosine (m6A) methylation-mediated degradation of RNA is essential for kidney development. However, m6A methylation impacts not only RNA stability, but also other RNA metabolism processes. How RNA decay affects the nephrotoxicity of colistin is largely unknown. Therefore, in this study, we verified that colistin could induce mouse kidney apoptosis through some apoptotic indicators, and confirmed the relationship between methylation and apoptosis through the detection of m6A methylation, thus elucidating the potential mechanism of colistin nephrotoxicity. The results showed that the renal tubule dilation and tubular structure were observed in the colistin group, and the oxidative stress index and ATPase activities were significantly different from those in the control group. Under electron microscope, the kidney in colistin group showed typical apoptotic morphological changes such as nuclear pyknosis, chromatin edge aggregation, and intact nuclear membrane, accompanied by significant changes in apoptosis-related genes. The level of m6A in the colistin group was significantly decreased, accompanied by downregulation of METTL3 mRNA and protein levels, and METTL3 was significantly correlated with apoptotic gene proteins. Data from this study suggested that m6A methylation was involved in oxidative stress-mediated apoptosis in the mechanism of colistin nephrotoxicity.

Ammonia exposure causes the disruption of the solute carrier family gene network in pigs.

Ammonia is the main harmful gas in livestock houses. However, the toxic mechanism of ammonia is still unclear. Therefore, we examined the effects of ammonia exposure on different tissues of fattening pigs by histological analysis and transcriptome techniques in this study. The results showed that there were varying degrees of pathological changes in liver, kidney, hypothalamus, jejunum, lungs, spleen, heart and trachea of fattening pigs under ammonia exposure. Notably, the extent of damage in liver, kidney, jejunum, lungs, hypothalamus and trachea was more severe than that in heart and spleen. Transcriptome results showed that ammonia exposure caused changes in 349, 335, 340, 229, 120, 578, 407 and 115 differentially expressed genes in liver, kidney, spleen, lung, trachea, hypothalamus, jejunum and heart, respectively. Interestingly, the changes in solute vector (SLC) family genes were found in all 8 tissues, and the verified gene results (SLC11A1, SLC17A7, SLC17A6, SLC6A4, SLC22A7, SLC25A3, SLC28A3, SLC7A2, SLC6A6, SLC38A5, SLC22A12, SLC34A1, SLC26A1, SLC26A6, SLC27A5, SLC22A8 and SLC44A4) were consistent with qRT-PCR results. In conclusion, ammonia exposure can cause pathological changes in many tissues and organs of fattening pigs and changes in the SCL family gene network. Importantly, the SCL family is involved in the toxic mechanism of ammonia. Our findings will provide a new insight for better assessing the mechanism of ammonia toxicity.

Correction: A liquid-crystal-based immunosensor for the detection of cardiac troponin I.

Correction for 'A liquid-crystal-based immunosensor for the detection of cardiac troponin I' by Chunli Xia et al., Analyst, 2020, 145, 4569-4575, DOI: 10.1039/D0AN00425A.

A liquid-crystal-based immunosensor for the detection of cardiac troponin I.

Cardiac troponin I (cTnI) is one of the most sensitive and specific markers of myocardial cell injury, which can detect even minor myocardial damages. It is recognized as the main biochemical marker of the rapid diagnosis of acute myocardial infarction (AMI) and acute coronary syndrome (ACS). In this study, a label-free biosensor that utilizes the birefringence property of a nematic liquid crystal (LC) for the detection of cTnI is demonstrated. A chemically sensitive film with specific molecular recognition ability was decorated on the surface of a substrate, and the LC molecules were arranged in a vertically oriented order under the influence of the sensitive film, and a dark background signal was obtained using a polarizing optical microscope. When the antigen-antibody specifically binds to form a stronger acting force, the orientation of the LC molecules changes, resulting in a bright optical appearance. This LC-based immunosensor not only has the advantages of a facile structure, low cost and excellent specificity but also high sensitivity (a low detection limit of 1 pg ml-1), and has a promising future in biomedical related fields.

METTL3/m6A/miRNA-873-5p Attenuated Oxidative Stress and Apoptosis in Colistin-Induced Kidney Injury by Modulating Keap1/Nrf2 Pathway.

Nephrotoxicity of colistin is the major factor limiting its clinical application. However, the exact mechanism of colistin-induced nephrotoxicity is still elusive. N6-Methyladenosine (m6A) modification has been implicated in many biological processes, however, its role in colistin-induced nephrotoxicity needs to be elucidated. Mouse renal tubular epithelial cells (mRTECs) were treated with 200 µM colistin with or without METTL3 overexpression. Cells injury, m6A assay, oxidative stress and apoptosis were examined. Levels of m6A are decreased after colistin treatment in mRTECs. METTL3 is the major factor involved in abnormal m6A modification. METTL3 overexpression plays a protective role against colistin-induced oxidative stress and apoptosis. Moreover, METTL3 interacts with the microprocessor protein DGCR8 and positively modulates miR-873-5p mature process in an m6A-dependent manner. Further experiments show that miR-873-5p could regulate Keap1-Nrf2 pathway against colistin-induced oxidative stress and apoptosis. These studies revealed an important role of METTL3/m6A in colistin-induced nephrotoxicity and provide a new insight on m6A modification in drug induced toxicity.

Fiber Mach-Zehnder-interferometer-based liquid crystal biosensor for detecting enzymatic reactions of penicillinase.

A novel, to the best of our knowledge, liquid crystal (LC) biosensor, based on an optical fiber Mach-Zehnder interferometer (MZI), is proposed. The proposed optical fiber MZI consists of two single-mode fibers and a tapered photonic crystal fiber (PCF). The PCF is coated with 4'-pentyl-biphenyl-4-carboxylic acid (PBA)-doped 4-cyano-4'-pentylbiphenyl (5CB). Being a pH-sensitive material, PBA can manipulate LC molecules to different orientations according to their pH values. When the orientation of LC molecules changes with varying pH, the effective refractive index of the cladding modes also is accordingly affected. Enzymatic reactions of penicillinase can release H+, which causes the decrease of the pH. Therefore, the enzymatic reactions of penicillinase can be sensed by monitoring the peak shift in the interference spectrum. The effects of the tapered diameter on the sensitivity of the sensor were experimentally investigated as well.

Liquid-crystal based Fabry-Perot interferometer displacement sensor.

A Fabry-Perot interferometer displacement sensor is proposed and demonstrated. This sensor is prepared by inserting two ceramic ferrules into a polydimethylsiloxane (PDMS) hose to generate a Fabry-Perot cavity. The cavity is filled with nematic liquid crystals (NLCs), which induce a Vernier effect due to the birefringence of NLCs. The flexible PDMS hose makes the cavity length adjustable. A displacement sensor with sensitivity of ∼2.97 nm/µm and a dynamic range of 0.9 mm at the center wavelength of 1550 nm is experimentally demonstrated.

Preventive effects of nerve growth factor against colistin-induced autophagy and apoptosis in PC12 cells.

In this study, the preventive effects of NGF against colistin-induced autophagy and apoptosis in PC12 cells have been investigated. Fluorescence microscopy, real-time PCR, transmission electron microscopy (TEM), flow cytometery, and western blotting technique were used. The results showed that large amounts of autophagosomes and apoptotic markers were triggered by colistin. Consistently, a significant increase has been noted at mRNA and protein levels in autophagy and apoptosis-related genes. Besides, TEM analysis showed that autophagic vacuoles were obvious at 12 h, while nuclear chromatin condensation and edge accumulation were clearly seen at 24 h in colistin alone group. Importantly, the visual autophagy and apoptosis were markedly reduced with NGF treatment in a dose-dependent manner. Moreover, colistin-induced reduction in mitochondrial membrane potential was partly attenuated by NGF in a dose dependent manner. In summary, NGF ameliorated colistin-induced apoptosis and autophagy, and partially recovered MMP in PC12 cells.

Mulberry Diels-Alder-type adducts from Morus alba as multi-targeted agents for Alzheimer's disease.

Mulberry Diels-Alder-type adducts (MDAAs) are a group of structurally unique natural products biosynthetically derived from the intermolecular [4 + 2] cycloaddition of a dehydroprenylphenol and a chalcone. In the current study, ten MDAAs, including an undescribed one, inethermulberrofuran C, were isolated from the root bark of Morus alba. The anti-Alzheimer's disease (anti-AD) properties of these isolates were systematically screened for a series of potential targets (Aß self-aggregation, tau aggregation, and ChEs) as well as the anti-neuroinflammatory and neuroprotective activities. Four compounds, mulberrofuran C, mulberrofuran K, mulberrofuran G, and isomulberrofuran G, turned out to be potent multi-targeted agents for AD. Among them, mulberrofuran K with a good blood-brain barrier (BBB) permeability (8.7 ±â€¯0.3 × 10-6 cm/s) was selected as a promising candidate for further mechanism study in glutamate-induced HT22 cell model, which showed its neuroprotective ability on up-regulation of the glutathione (GSH) level and suppression of the reactive oxygen species (ROS) production.

Synthesis and evaluation of 1,2,3,4-tetrahydro-1-acridone analogues as potential dual inhibitors for amyloid-beta and tau aggregation.

Amyloid-ß (Aß) and tau protein are two crucial hallmarks in Alzheimer's disease (AD). Their aggregation forms are thought to be toxic to the neurons in the brain. A series of new 1,2,3,4-tetrahydro-1-acridone analogues were designed, synthesized, and evaluated as potential dual inhibitors for Aß and tau aggregation. In vitro studies showed that compounds 25-30 (20 µM) with N-methylation of the quinolone ring effectively inhibited Aß1-42 aggregation by 84.7%-99.5% and tau aggregation by 71.2%-101.8%. Their structure-activity relationships are discussed. In particular, 30 could permeate the blood-brain barrier, bind to Aß1-42 and tau, inhibit Aß1-42 ß-sheets formation, and prevent tau aggregation in living cells.

Design, synthesis and evaluation of 2-arylethenyl-N-methylquinolinium derivatives as effective multifunctional agents for Alzheimer's disease treatment.

A series of 2-arylethenyl-N-methylquinolinium derivatives were designed and synthesized based on our previous research of 2-arylethenylquinoline analogues as multifunctional agents for the treatment of Alzheimer's disease (AD) (Eur. J. Med. Chem. 2015, 89, 349-361). The results of in vitro biological activity evaluation, including ß-amyloid (Aß) aggregation inhibition, cholinesterase inhibition, and antioxidant activity, showed that introduction of N-methyl in quinoline ring significantly improved the anti-AD potential of compounds. The optimal compound, compound a12, dramatically attenuated the cell death of glutamate-induced HT22 cells by preventing the generation of ROS and increasing the level of GSH. Most importantly, intragastric administration of a12•HAc was well tolerated at doses up to 2000 mg/kg and could traverse blood-brain barrier.

p53 Mediates Colistin-Induced Autophagy and Apoptosis in PC-12 Cells.

The mechanism of colistin-induced neurotoxicity is still unknown. Our recent study (L. Zhang, Y. H. Zhao, W. J. Ding, G. Z. Jiang, Z. Y. Lu, L. Li, J. L. Wang, J. Li, and J. C. Li, Antimicrob Agents Chemother 59:2189-2197, 2015, http://dx.doi.org/10.1128/AAC.04092-14; H. Jiang, J. C. Li, T. Zhou, C. H. Wang, H. Zhang, and H. Wang, Int J Mol Med 33:1298-1304, 2014, http://dx.doi.org/10.3892/ijmm.2014.1684) indicates that colistin induces autophagy and apoptosis in rat adrenal medulla PC-12 cells, and there is interplay between both cellular events. As an important cellular stress sensor, phosphoprotein p53 can trigger cell cycle arrest and apoptosis and regulate autophagy. The aim of the present study was to investigate the involvement of the p53 pathway in colistin-induced neurotoxicity in PC-12 cells. Specifically, cells were treated with colistin (125 µg/ml) in the absence and presence of a p53 inhibitor, pifithrin-α (PFT-α; 20 nM), for 12 h and 24 h, and the typical hallmarks of autophagy and apoptosis were examined by fluorescence/immunofluorescence microscopy and electron microscopy, real-time PCR, and Western blotting. The results indicate that colistin had a stimulatory effect on the expression levels of the target genes and proteins involved in autophagy and apoptosis, including LC3-II/I, p53, DRAM (damage-regulated autophagy modulator), PUMA (p53 upregulated modulator of apoptosis), Bax, p-AMPK (activated form of AMP-activated protein kinase), and caspase-3. In contrast, colistin appeared to have an inhibitory effect on the expression of p-mTOR (activated form of mammalian target of rapamycin), which is another target protein in autophagy. Importantly, analysis of the levels of p53 in the cells treated with colistin revealed an increase in nuclear p53 at 12 h and cytoplasmic p53 at 24 h. Pretreatment of colistin-treated cells with PFT-α inhibited autophagy and promoted colistin-induced apoptosis. This is the first study to demonstrate that colistin-induced autophagy and apoptosis are associated with the p53-mediated pathway.

Syntheses And Evaluation Of Asymmetric Curcumin Analogues As Potential Multifunctional Agents For The Treatment Of Alzheimer's Disease.

A series of new asymmetric curcumin analogues were synthesized and evaluated as potential multifunctional agents for the treatment of Alzheimer's disease. Our results showed that most of these synthetic compounds had better inhibitory properties against Aß aggregation compared with curcumin, and better anti-oxidative properties compared with the reference compound Trolox through the study of oxygen radical absorbance capacity (ORAC). Some compounds showed good properties in selectively chelating metal ions such as copper and iron. Besides, some compounds were found to be able to dissociate Aß protein which had already aggregated. The structure-activity relationships (SAR) of these synthetic compounds were studied. The present investigation indicated that our synthetic asymmetric curcumin derivatives could be potential multifunctional agents for the treatment of Alzheimer's disease (AD).

Design, synthesis, and biological evaluation of 2-arylethenylquinoline derivatives as multifunctional agents for the treatment of Alzheimer's disease.

A series of new 2-arylethenylquinoline derivatives (4a1-4a12, 4b1-4b8, 4c1-4c4, 4d1-4d3 and 4e1-4e9) were designed, synthesized, and evaluated as potential multifunctional agents for the treatment of Alzheimer's disease (AD). In vitro studies showed that these synthetic compounds inhibited self-induced Aß1-42 aggregation effectively ranged from 23.6% to 83.9% at the concentration of 20 µM, and acted as potential antioxidants and biometal chelators. Their structure-activity relationships were obtained and discussed. In particular, compound 4b1, the most active compound, displayed strong inhibitory activity with an IC50 value of 9.7 µM for self-induced Aß1-42 aggregation, good antioxidative activity with a value of 3.9-fold of Trolox, potent inhibitory activity for cholinesterase with IC50 values of 0.2 µM and 64.1 µM against butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE), respectively. Besides, 4b1 was also capable of disassembling the self-induced Aß1-42 aggregation fibrils with a ratio of 59.8% at 20 µM concentration, and had a good metal chelating activity. Taken together, these results suggest that compound 4b1 might be a promising lead compound for AD treatment.

[Effects of iloprost combined with low dose tadalafil in adult congenital heart disease patients with severe pulmonary arterial hypertension: a single-center, open-label controlled study].

OBJECTIVE: To evaluate the therapy efficacy of iloprost combined with low dose tadalafil in adult congenital heart disease (CHD) patients with severe pulmonary arterial hypertension (PAH). METHODS: Adult CHD patients with severe PAH were included and divided into the sequential combination therapy group [iloprost: 10 µg/inhalation, 6 times per day for 6 months, and then add oral tadalafil (5 mg/d) till 12 months, n = 32] and upfront combination therapy group [iloprost: 10 µg/inhalation, 6 times per day combined with oral tadalafil (5 mg) for 12 months, n = 36]. Data on 6 min walking test (6MWT), Borg dyspnea score, oxygen saturation measurement, WHO classification, and cardiac catheterization were obtained at baseline, 6 and 12 months. RESULTS: Seventy-two patients were enrolled in the study and 68 patients completed the study. Pulmonary vascular resistance (PVR) was significantly reduced in the sequential combination therapy group[ (12.96 ± 6.48 ) Wood U vs. (16.94 ± 8.11) Wood U, P < 0.05] and in the upfront combination therapy group [(12.45 ± 7.32) Wood U vs. (16.73 ± 9.28) Wood U, P < 0.05] while pulmonary blood flow [(6.77 ± 3.17) L/min vs. (5.08 ± 2.36) L/min, P < 0.05; (6.95 ± 3.32) L/min vs. (5.03 ± 2.32) L/min, P < 0.05], the 6 MWD were significantly increased [(458 ± 59) m vs. (427 ± 65) m, P < 0.05; (494 ± 59) m vs. (436 ± 62) m, P < 0.01], the Borg dyspnea score (2.04 ± 0.72 vs. 2.52 ± 0.79, P < 0.05; 1.72 ± 0.73 vs. 2.51 ± 0.77, P < 0.01) was significantly improved in both groups at 6 months compared to baseline levels. In the upfront combination therapy group, venous oxygen saturation [(68.4 ± 9.3)% vs. (62.9 ± 9.5)%, P < 0.05] and systemic oxygen saturation during exercise[ (87.2 ± 9.7)% vs. (83.1 ± 15.6)%, P < 0.05]at 6 months were also significantly improved compared to baseline. At month 12, significantly lowered pulmonary artery pressure, PVR, Rp/Rs and increased pulmonary blood flow and cardiac index were evidenced in both groups compared to baseline. CONCLUSION: Iloprost combined with low dose tadalafil regimen can effectively reduce PVR, increase 6MWD, and improve cardiopulmonary function in adults CHD patients with severe PAH. Compared with the sequential therapy regimen, the upfront combination therapy regimen can more rapidly improve the clinical symptoms of patients.