A key feature of Alzheimer's disease (AD) is an early and severe degeneration of the cholinergic projections throughout the brain. This characteristic is also shared by Lewy Body Dementia, Parkinson's disease dementia and Down's syndrome. Expression of the core acetylcholine (ACh) biosynthesizing enzyme, choline acetyltransferase (ChAT) defines this widespread neuronal system. Thereby ChAT was chosen as a prominent target for developing new in vivo probes for mapping cholinergic network, and designing novel cholinergic enhancing therapeutic agents. Advanced in silico molecular modelling analysis was used to screen diverse drug registries and an in-house molecular library against ChAT. The in silico hits were then examined with a robust in-house invented high-throughput ChAT assays using human recombinant protein and postmortem tissue extracts of 3 different brain regions of a group of AD (n=6) and controls (n=6). All hits were also tested against ACh degrading enzymes, AChE and BChE. We identified two different class of ChAT ligands. One class acted as highly potent inhibitor of ChAT, with low nanomolar activity. They show negligible activity against ACh degrading enzymes, indicating high selectivity for ChAT. The second class, on the contrary enhanced the intrinsic catalytic rate of ACh-biosynthesis by ChAT. These compounds compose the first ever identified small molecules, and are termed by us as ChAT Potentiating Ligands (CPLs). Systematic enzymes kinetic analyses identified 10 CPLs with EC50 values in low micromolar ranges. Some of CPLs also acted on AChE and/or BChE but as inhibitors. These are hence expected to exhibit a potentially dual mode of cholinergic enhancing actions of both increasing the biosynthesis of ACh, and inhibiting its degradation. Given the early and selective degeneration of the central cholinergic neurons in the major dementia disorders and ChAT being the defining marker of this neuronal system, the high affinity and selective ChAT inhibitors are being tested as ChAT-PET tracer. The CPLs on the other hand constitute a novel class of compounds of cholinergic enhancing agents that act by increasing biosynthesis of acetylcholine rather than preventing its degradation. They are hence expected to show superior efficacy than the currently in use cholinesterase inhibitors.
The Heart failure (HF) is considered as the end-stage of various heart disease and associated with high mortality globally. Progressive loss of cardiac myocytes via apoptosis is considered as the most important factor for HF pathology. In this study, we demonstrated that Safflower extract was able to inhibitthe apoptosis inducted by Angiotensin II (AngII) in a ratmyocardium derived cell line H9C2. Further examination of LC-3II conversion and autophagosome formation suggested Safflower extract induced autophagy in treated cell. Inhibition of Safflower extract induced autophagy by 3-methyladenine (3MA) abolished anti-apoptotic function of Safflower extract, while application of autophagy stimulator Rapamycin in H9C2 inhibited apoptosis as well. Moreover, treatment of H9C2 cell with Safflower extract also inhibited expression of pro-apoptotic genes BAD and Bax. In conclusion, our data indicated that Safflower extract inhibit apoptosis via inducing autophagy in myocardium cell and demonstrated the potential as novel therapeutic drug for Heart failure.
The repair activities and reaction mechanisms of phenylpropanoid glycosides (PPGs) and their analogues, isolated from Chinese folk medicinal herbs, towards oxidative DNA damage were studied with pulse radiolytic technique. On pulse irradiation of nitrogen-saturated 4 mM poly C aqueous solution containing one of the tested polyphenols, 40 mM K2S2O8 and 200 mM t-BuOH, the transient absorption spectrum of the oxidative radical of poly C decays with the concurrent formation of the phenoxyl radical of the tested polyphenols within several tens of microseconds after the electron pulse irradiation. The result indicated that there was a repair reaction between oxidative radical of poly C and the tested polyphenols. The repair activities also were observed for the tested polyphenols towards the radical cations of single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). The rate constants were determined to be 3.7–6.4 × 109, 4.8–5.5 × 108 and 8.8–10.3 × 108 M−1·sec−1 for the repair reactions of oxidative radical of poly C and radical cations of ssDNA and dsDNA, respectively. The result of this study together with those of our previous studies demonstrates that PPGs and their analogues can fast repair not only the damage of deoxynucleoside and deoxynucleotide but also the damage of integral DNA, with the latter being closer to a cellular condition.
The neuropathological hallmark of Parkinsońs disease, multiple system atrophy and dementia with Lewy bodies is the accumulation of α-synuclein. The development of an imaging biomarker for α-synuclein is an unmet need. To date, no selective α-synuclein imaging agent has been identified, though initial studies suggest that the tau tracer [11C]PBB3 displays some degree of binding to α-synuclein. In this study, a series of compounds derived from the PBB3 scaffold were examined using fluorescence imaging and tissue microarrays (TMAs) derived from brain samples with different proteinopathies. One compound, C05-01, was selected based on its higher fluorescence signal associated with Lewy body aggregates compared with other PBB3 analogues. In vitro binding assays using human brain homogenates and recombinant fibrils indicated that C05-01 had higher affinity for α-synuclein (KD/Ki 25 nM for fibrils, Ki 3.5 nM for brain homogenates) as compared with PBB3 (KD 58 nM). In autoradiography (ARG) studies using fresh frozen human tissue and TMAs, [3H]C05-01 displayed specific binding in cases with α-synuclein pathology. C05-01 is the first PBB3 analogue developed as a potential compound targeting α-synuclein. Despite improved affinity for α-synuclein, C05-01 showed specific binding in AD tissue with Amyloid β and tau pathology, as well as relatively high non-specific and off-target binding. Additional efforts are needed to optimize the pharmacological and physicochemical properties of this series of compounds as ligands for α-synuclein. This study also showed that the construction of TMAs from different proteinopathies provides a tool for evaluation of fluorescent or radiolabelled compounds binding to misfolded proteins.
The homo-pentameric alpha 7 receptor is one of the major types of neuronal nicotinic acetylcholine receptors (α7-nAChRs) related to cognition, memory formation, and attention processing. The mapping of α7-nAChRs by PET pulls a lot of attention to realize the mechanism and development of CNS diseases such as AD, PD, and schizophrenia. Several PET radioligands have been explored for the detection of the α7-nAChR.
The G-protein-coupled receptor 44 (GPR44) is a beta cell-restricted target that may serve as a marker for beta cell mass (BCM) given the development of a suitable PET ligand. The binding characteristics of the selected candidate, AZ12204657, at human GPR44 were determined using in vitro ligand binding assays. AZ12204657 was radiolabeled using 11C- or 3H-labeled methyl iodide ([11C/3H]CH3I) in one step, and the conversion of [11C/3H]CH3I to the radiolabeled product [11C/3H]AZ12204657 was quantitative. The specificity of radioligand binding to GPR44 and the selectivity for beta cells were evaluated by in vitro binding studies on pancreatic sections from human and non-human primates as well as on homogenates from endocrine and exocrine pancreatic compartments. The radiochemical purity of the resulting radioligand [11C]AZ12204657 was > 98%, with high molar activity (MA), 1351 ± 575 GBq/μmol (n = 18). The radiochemical purity of [3H]AZ12204657 was > 99% with MA of 2 GBq/μmol. Pancreatic binding of [11C/3H]AZ12204657 was co-localized with insulin-positive islets of Langerhans in non-diabetic individuals and individuals with type 2 diabetes (T2D). The binding of [11C]AZ12204657 to GPR44 was > 10 times higher in islet homogenates compared to exocrine homogenates. In human islets of Langerhans GPR44 was co-expressed with insulin, but not glucagon as assessed by co-staining and confocal microscopy. We radiolabeled [11C]AZ12204657, a potential PET radioligand for the beta cell-restricted protein GPR44. In vitro evaluation demonstrated that [3H]AZ12204657 and [11C]AZ12204657 selectively target pancreatic beta cells. [11C]AZ12204657 has promising properties as a marker for human BCM.
Objective: This retrospective cohort study is to analyze the impacts of CYP2C19 polymorphism and clopidogrel dosing on in-stent restenosis (ISR) after coronary stenting. Methods: Totally, 111 patients were included, who underwent percutaneous coronary intervention (PCI) with drug-eluting stent. Patients received clopidogrel treatment after the intervention on the background treatment with aspirin, based on the genotypes: 75 mg clopidogrel once each day for subjects without CYP2C19 loss-of-function (LOF) alleles (n=51; EM), 75 mg clopidogrel once each day (n=27; IM75) or twice each day (n=33; IM150) for subjects with one CYP2C19 LOF allele. ISR at 3– 18 months after coronary stenting was assessed. Results: ISR rate was significantly higher in the IM75 group (40.7%) than the EM group (11.8%). ISR rate in the IM150 group was lower than the IM75 group (6.1% vs 40.7%), and comparable to that in the EM group. Multivariate logistic regression showed that both CYP2C19 genotype and clopidogrel dosing were associated with the risk of ISR after adjusting the relevant confounding factors. ISR risk was higher in the IM patients than the EM patients. Patients with clopidogrel dose of 75 mg once each day had significantly higher risk of ISR than those with the dose of 75 mg twice each day. Conclusion: Increased dose of clopidogrel may reduce the risk of ISR after PCI in CYP2C19 LOF allele(s) carriers. The presence of CYP2C19 LOF allele(s) increases the risk of ISR after stenting, which could be counteracted by the increased dose of clopidogrel. Keywords: CYP2C19 polymorphism, in-stent restenosis, ISR, clopidogrel, percutaneous coronary intervention, PCI
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)