Synthesis, preliminarily biological evaluation and molecular docking study of new Olaparib analogues as multifunctional PARP-1 and cholinesterase inhibitors.

A series of new Olaparib derivatives was designed and synthesized, and their inhibitory activities against poly (ADP-ribose) polymerases-1 (PARP-1) enzyme and cancer cell line MDA-MB-436 in vitro were evaluated. The results showed that compound 5l exhibited the most potent inhibitory effects on PARP-1 enzyme (16.10 ± 1.25 nM) and MDA-MB-436 cancer cell (11.62 ± 2.15 µM), which was close to that of Olaparib. As a PARP-1 inhibitor had been reported to be viable to neuroprotection, in order to search for new multitarget-directed ligands (MTDLs) for the treatment of Alzheimer's disease (AD), the inhibitory activities of the synthesized compounds against the enzymes AChE (from electric eel) and BChE (from equine serum) were also tested. Compound 5l displayed moderate BChE inhibitory activity (9.16 ± 0.91 µM) which was stronger than neostigmine (12.01 ± 0.45 µM) and exhibited selectivity for BChE over AChE to some degree. Molecular docking studies indicated that 5l could bind simultaneously to the catalytic active of PARP-1, but it could not interact well with huBChE. For pursuit of PARP-1 and BChE dual-targeted inhibitors against AD, small and flexible non-polar groups introduced to the compound seemed to be conducive to improving its inhibitory potency on huBChE, while keeping phthalazine-1-one moiety unchanged which was mainly responsible for PARP-1 inhibitory activity. Our research gave a clue to search for new agents based on AChE and PARP-1 dual-inhibited activities to treat Alzheimer's disease.

In silico-determined compound from the root of Pueraria lobate alleviates synaptic plasticity injury induced by Alzheimer's disease via the p38MAPK-CREB signaling pathway.

Pueraria lobata is utilized as a food source in China. The aim of this study is to combine virtual screening and molecular dynamics predictive model to screen out the potential synaptic plasticity-maintaining components from the root of P. lobate and to verify it by employing the amyloid ß-injected rats' model. Eighteen compounds were identified by HPLC-MS/MS; puerarin manifested the most potential to form a stable complex with calcium/calmodulin kinase IIα (CaMK IIα), which is the key protein in synaptic plasticity by the in silico study. The further in vivo assay showed that puerarin could elevate the synaptic thickness, density, and length, relieve calcium overload, regulate the expression of CaMK IIα, and other p38MAPK-CREB signaling pathway-related biochemical criteria. The behavioral test also verified the results. Results have confirmed that the root of P. lobate can work anti-AD by maintaining the synaptic plasticity and proved the reliability of using the in silico predictive model to determine active ingredients from the natural product.

ZJM-289, a novel nitric oxide donor, alleviates the cerebral ischaemic-reperfusion injury in rats.

1. Current studies indicate that nitric oxide (NO) plays a dual role as both a protective and pathogenic factor in focal cerebral ischaemia depending on the level, location, source and environment. The present study hypothesized that the NO donor ZJM-289 could inhibit cerebral ischaemia-reperfusion (I/R) injury and investigated the mechanism of the beneficial events. 2. Adult male rats were randomly divided into four groups: (i) sham operated; (ii) I/R (ischaemia for 90 min and reperfusion for 24 h) treated with vehicle; (iii) I/R treated with 0.1 mmol/kg body weight ZJM-289; and (iv) I/R treated with 0.2 mmol/kg body weight ZJM-289. We evaluated the changes in brain infarction, brain-water content, neurological deficits and histopathology. Western blot analysis was used to study the expression of endothelial nitric oxide synthase (eNOS) and neuronal nitric oxide synthase (nNOS) in the brain after I/R. The levels of NO and cyclic guanosine monophosphate (cGMP) were also determined. 3. ZJM-289 reduced infarct volume and brain-water content in ischemic brains and promoted functional recovery. Western blotting showed significant inhibition of nNOS in ZJM-289 treated rats compared with untreated rats. However, eNOS expression in the ischemic brain was enhanced in the ZJM-289 groups. The cGMP and NO levels increased in the ZJM-289 groups after I/R. The study showed that ZJM-289 could alleviate cerebral injury after I/R through inhibition of nNOS and stimulation of the NO/soluble guanylate cyclase/cGMP pathway. Therefore, a suitable NO donor might be an effective candidate for the treatment of acute stroke by neuroprotection.

In silico identification of AChE and PARP-1 dual-targeted inhibitors of Alzheimer's disease.

Alzheimer's disease (AD) is a chronic neurodegenerative disease of the elderly that seriously affects the quality of life and the life expectancy of those affected. There is, as yet, no effective drug treatment of AD, although several acetylcholinesterase (AChE) inhibitors and a glutamate antagonist can provide relief from its symptoms. Recent studies have indicated that the overactivation of poly(ADP-ribose) polymerase-1 (PARP-1) may promote nerve cell death in the brains of AD patients, implying that PARP-1 inhibition may have therapeutic value for the treatment of AD. Therefore, it is important to investigate novel agents with both AChE- and PARP-1-inhibitory bioactivities. In this study, the structure-based virtual screening of PARP-1 inhibitors was performed to search for potential agents with high affinities for AChE. The dynamic stability of the selected AChE-ligand complexes was investigated by molecular dynamics (MD) simulation. Two compounds, CID57390505 and CID71605390, showed high affinities for and stability in complex with AChE in docking and MD simulations. Thus, our in silico research identified two compounds with AChE and PARP-1 dual-targeted activities, indicating that this technique could aid attempts to develop more potent agents against AD.

The emerging role of microRNA-4487/6845-3p in Alzheimer's disease pathologies is induced by Aß25-35 triggered in SH-SY5Y cell.

BACKGROUND: Accumulation of amyloid ß-peptide (Aß) is implicated in the pathogenesis and development of Alzheimer's disease (AD). Neuron-enriched miRNA was aberrantly regulated and may be associated with the pathogenesis of AD. However, regarding whether miRNA is involved in the accumulation of Aß in AD, the underlying molecule mechanism remains unclear. Therefore, we conduct a systematic identification of the promising role of miRNAs in Aß deposition, and shed light on the molecular mechanism of target miRNAs underlying SH-SY5Y cells treated with Aß-induced cytotoxicity. RESULTS: Statistical analyses of microarray data revealed that 155 significantly upregulated and 50 significantly downregulated miRNAs were found on the basis of log2 | Fold Change | ≥ 0.585 and P < 0.05 filter condition through 2588 kinds of mature miRNA probe examined. PCR results show that the expression change trend of the selected six miRNAs (miR-6845-3p, miR-4487, miR-4534, miR-3622-3p, miR-1233-3p, miR-6760-5p) was consistent with the results of the gene chip. Notably, Aß25-35 downregulated hsa-miR-4487 and upregulated hsa-miR-6845-3p in SH-SY5Y cell lines associated with Aß-mediated pathophysiology. Increase of hsa-miR-4487 could inhibit cells apoptosis, and diminution of hsa-miR-6845-3p could attenuate axon damage mediated by Aß25-35 in SH-SY5Y. CONCLUSIONS: Together, these findings suggest that dysregulation of hsa-miR-4487 and hsa-miR-6845-3p contributed to the pathogenesis of AD associated with Aß25-35 mediated by triggering cell apoptosis and synaptic dysfunction. It might be beneficial to understand the pathogenesis and development of clinical diagnosis and treatment of AD. Further, our well-designed validation studies will test the miRNAs signature as a prognostication tool associated with clinical outcomes in AD.

Opposite effects of HDAC5 and p300 on MRTF-A-related neuronal apoptosis during ischemia/reperfusion injury in rats.

Our recent study has revealed that the myocardin-related transcription factor-A (MRTF-A) is involved in the apoptosis of cortical neurons induced by ischemia/reperfusion (I/R). Histone deacetylase 5 (HDAC5) and histone acetyltransferase p300 (P300) are two well-known regulators for transcription factors; however, their roles in MRTF-A-related effect on neuronal injuries during I/R are still unclear. In this study, in a model rat cerebral I/R injury via middle cerebral artery occlusion and reperfusion, we found that the expression and activity of HDAC5 was upregulated, whereas p300 and MRTF-A were downregulated both in expression and activity during I/R. Their expression changes and the interaction of the MRTF-A with HDAC5 or p300 were further verified by double immunofluorescence and co-immunoprecipitation. In cultured neuronal apoptosis model induced by H2O2, MRTF-A exhibited an anti-apoptotic effect by enhancing the transcription of Bcl-2 and Mcl-1 via CArG box binding. MRTF-A-induced anti-apoptotic effect was effectively inhibited by HDAC5, but was significantly enhanced by p300. The results suggest that both HDAC5 and p300 are involved in MRTF-A-mediated effect on neuronal apoptosis during ischemia/reperfusion injury, but with opposite effects.

SIRT2 mediated antitumor effects of shikonin on metastatic colorectal cancer.

SIRT2 is involved in the development of a variety of cancers. Shikonin is a natural compound that is known to have antitumor effects. This study aims to assess the effects of shikonin on the development and metastatic progression of colorectal cancer (CRC) through regulation of SIRT2 expression and whether this effect is related to the phosphorylation of extracellular signal-regulated kinases (ERKs). The results demonstrated that SIRT2 is downregulated in CRC biopsy samples (n=31) compared with the adjacent non-cancerous tissues (ANCT, n=26). Furthermore, CRC metastases were positive for SIRT2 despite a lack of expression in the primary tumor. In addition, data from an in vitro assay revealed that overexpression of SIRT2 inhibited the proliferation and metastatic progression of SW480 cells while blocking of SIRT2 expression induced the proliferation and metastatic progression of HT29 cells. Shikonin inhibited the viability, migration and invasion of SW480 cells and it also inhibited the tumor growth in the nude mice model; while AGK2 (a specific inhibitor of SIRT2) reversed these effects. Epidermal growth factor (EGF, an activator of ERK) and ERK-overexpression inhibited the effects of shikonin on SIRT2 expression, proliferation and metastasis in SW480 cells. However, this proliferative effect of EGF was reversed by SIRT2 overexpression. In conclusion, these results suggest that SIRT2 is a new therapeutic target for the treatment of CRC. The antitumor effects of shikonin on CRC seem to be mediated by SIRT2 upregulation via phospho-ERK inhibition.

The role of myocardin-related transcription factor-A in Aß25-35 induced neuron apoptosis and synapse injury.

Myocardin-related transcription factor-A (MRTF-A) highly expressed in brain has been demonstrated to promote neuronal survival via regulating the transcription of related target genes as a powerful co-activator of serum response factor (SRF). However, the role of MRTF-A in Alzheimer's disease (AD) is still unclear. Here, we showed that MRTF-A was significantly downregulated in cortex of the Aß25-35-induced AD rats, which played a key role in Aß25-35 induced cerebral neuronal degeneration in vitro. Bilateral intracerebroventricular injection of Aß25-35 caused significantly MRTF-A expression decline in cortex of rats, along with significant neuron apoptosis and plasticity damage. In vitro, transfection of MRTF-A into primary cultured cortical neurons prevented Aß25-35 induced neuronal apoptosis and synapses injury. And luciferase reporter assay determined that MRTF-A could bind to and enhance the transactivity of the Mcl-1 (Myeloid cell leukemia-1) and Arc (activity-regulated cytoskeletal-associated protein) promoters by activating the key CArG box element. These data demonstrated that the decreasing of endogenous MRTF-A expression might contribute to the development of AD, whereas the upregulation MRTF-A in neurons could effectively reduce Aß25-35 induced synapse injury and cell apoptosis. And the underlying mechanism might be partially due to MRTF-A-mediated the transcription and expression of Mcl-1 and Arc by triggering the CArG box.

Baicalin inhibiting cerebral ischemia/hypoxia-induced neuronal apoptosis via MRTF-A-mediated transactivity.

Baicalin has been shown to provide the neuroprotective effect by alleviating cerebral ischemia injury. However, little's known about the underlying mechanism. Here, a cerebral artery occlusion (MACO)/reperfusion rat model and rat primary cortical neuron culture exposed to hydrogen peroxide (H2O2) were established to evaluate the effect of baicalin on ischemia-induced neuronal apoptosis. We found baicalin can significantly less neurological deficit and reduced infarct volume in vivo. And it efficiently inhibited neuronal apoptosis in vivo and vitro, which was especially characterized by the enhancing of transcription and expression of myeloid cell leukemia-1 (MCL-1) and B-cell lymphoma-2 (BCL-2) in a dose-dependent manner. Furthermore, Baicalin markedly increased myocardin-related transcription factor-A (MRTF-A) level either in ischemic hemisphere or in primary cortical neuron cultures, whiles the anti-apoptosis effect of baicalin was significantly inhibited by transfected with the small interfering RNA of MRTF-A (MRTF-A siRNA) in primary cortical neuron cultures. The luciferase assays also indicated baicalin enhanced the transactivity of MCL-1 and BCL-2 promoter by activating the key CArG box (CC [A/T] 6GG) element, which was reduced by MRTF-A siRNA, suggesting MRTF-A may participate the anti-apoptosis effect of baicalin, and MRTF-A was involved in the transcriptional activity of MCL-1 and BCL-2 that was induced by baicalin. LY294002 (phosphatidylinositol-3 kinase (PI3K) inhibitor) and PD98059 (extracellular signal regulates kinase-1/2 (ERK1/2) inhibitor) obviously reduced baicalin-induced MRTF-A expression and transactivity and expression of MCL-1 and BCL-2, which further abolished the anti-apoptotic effect of baicalin on neuronal apoptosis. Taken together, our data provided the evidence demonstrating the neuroprotective effect of baicalin partially due to MRTF-A-mediated transactivity and expression of MCL-1 and BCL-2 by triggering the CArG box, which might be controlled by the activation of PI3K and ERK1/2.