Photo-Enhanced Synergistic Induction of Ferroptosis for Anti-Cancer Immunotherapy.

Ferroptosis as programmed cell death received considerable attention in cancer research. Recently, studies have associated ferroptosis with photodynamic therapy (PDT) because PDT promotes glutathione (GSH) deletion, glutathione peroxidase 4 (GPX4) degradation, and lipid peroxide accumulation. However, PDT-induced ferroptosis may be potentially prevented by ferroptosis suppressor protein 1 (FSP1). To address this limitation, herein, a novel strategy is developed to trigger ferroptosis by PDT and FSP1 inhibition. For enhancement of this strategy, a photoresponsive nanocomplex, self-assembled by BODIPY-modified poly(amidoamine) (BMP), is utilized to stably encapsulate the inhibitor of FSP1 (iFSP1) and chlorin e6 (Ce6). The nanosystem promotes intracellular delivery, penetration, and accumulation of ferroptosis inducers in tumors with light irradiation. The nanosystem presents high-performance triggering of ferroptosis and immunogenic cell death (ICD) in vitro and in vivo. Importantly, the nanoparticles increase tumor infiltration of CD8+ T cells and further enhance the efficacy of anti-PD-L1 immunotherapy. The study suggests the potential of photo-enhanced synergistic induction of ferroptosis by the photoresponsive nanocomplexes in cancer immunotherapy.

Fibroblast Growth Factor-Based Pharmacotherapies for the Treatment of Obesity-Related Metabolic Complications.

The fibroblast growth factor (FGF) family, which comprises 22 structurally related proteins, plays diverse roles in cell proliferation, differentiation, development, and metabolism. Among them, two classical members (FGF1 and FGF4) and two endocrine members (FGF19 and FGF21) are important regulators of whole-body energy homeostasis, glucose/lipid metabolism, and insulin sensitivity. Preclinical studies have consistently demonstrated the therapeutic benefits of these FGFs for the treatment of obesity, diabetes, dyslipidemia, and nonalcoholic steatohepatitis (NASH). Several genetically engineered FGF19 and FGF21 analogs with improved pharmacodynamic and pharmacokinetic properties have been developed and progressed into various stages of clinical trials. These FGF analogs are effective in alleviating hepatic steatosis, steatohepatitis, and liver fibrosis in biopsy-confirmed NASH patients, whereas their antidiabetic and antiobesity effects are mildand vary greatly in different clinical trials. This review summarizes recent advances in biopharmaceutical development of FGF-based therapies against obesity-related metabolic complications, highlights major challenges in clinical implementation, and discusses possible strategies to overcome these hurdles.

Lean body mass and the cardiovascular system constitute a female-specific relationship.

Recent evidence points toward a link between lean body mass (LBM) and cardiovascular capacity in women. This study aimed at determining the sex-specific relationship of LBM with central and peripheral circulatory variables in healthy women and men (n=70) matched by age (60±12 years versus 58±15 years), physical activity, and cardiovascular risk factors. Regional (legs, arms, and trunk) and whole-body (total) body composition were assessed via dual-energy x-ray absorptiometry. Cardiac structure, function, and central/peripheral hemodynamics were measured via transthoracic echocardiography and the volume-clamp method at rest and peak incremental exercise. Regression analyses determined sex-specific relationships between LBM and cardiovascular variables. Regional and total LBM were lower in women than men (P<0.001), with little overlap between sexes. Leg and arm LBM positively associated with left ventricular (LV) internal resting dimensions in women (r≥0.53, P≤0.002) but not men (P≥0.156). Leg, arm, and total LBM only associated with LV relaxation in women (r≥0.43, P≤0.013). All LBM variables strongly associated with LV volumes at peak exercise in women (r≥0.54, P≤0.001) but not men and negatively associated with total peripheral resistance at peak exercise in women (r≥0.43, P≤0.023). Adjustment by adiposity-related or cardiovascular risk factors did not alter results. In conclusion, leg and arm LBM independently associate with internal cardiac dimensions, ventricular relaxation, and systemic vascular resistance in a sex-specific manner, with these relationships exclusively present in women.

FGF21-Sirtuin 3 Axis Confers the Protective Effects of Exercise Against Diabetic Cardiomyopathy by Governing Mitochondrial Integrity.

BACKGROUND: Exercise is an effective nonpharmacological strategy to alleviate diabetic cardiomyopathy (DCM) through poorly defined mechanisms. FGF21 (fibroblast growth factor 21), a peptide hormone with pleiotropic benefits on cardiometabolic homeostasis, has been identified as an exercise responsive factor. This study aims to investigate whether FGF21 signaling mediates the benefits of exercise on DCM, and if so, to elucidate the underlying mechanisms. METHODS: The global or hepatocyte-specific FGF21 knockout mice, cardiomyocyte-selective ß-klotho (the obligatory co-receptor for FGF21) knockout mice, and their wild-type littermates were subjected to high-fat diet feeding and injection of streptozotocin to induce DCM, followed by a 6-week exercise intervention and assessment of cardiac functions. Cardiac mitochondrial structure and function were assessed by electron microscopy, enzymatic assays, and measurements of fatty acid oxidation and ATP production. Human induced pluripotent stem cell-derived cardiomyocytes were used to investigate the receptor and postreceptor signaling pathways conferring the protective effects of FGF21 against toxic lipids-induced mitochondrial dysfunction. RESULTS: Treadmill exercise markedly induced cardiac expression of ß-klotho and significantly attenuated diabetes-induced cardiac dysfunction in wild-type mice, accompanied by reduced mitochondrial damage and increased activities of mitochondrial enzymes in hearts. However, such cardioprotective benefits of exercise were largely abrogated in mice with global or hepatocyte-selective ablation of FGF21, or cardiomyocyte-specific deletion of ß-klotho. Mechanistically, exercise enhanced the cardiac actions of FGF21 to induce the expression of the mitochondrial deacetylase SIRT3 by AMPK-evoked phosphorylation of FOXO3, thereby reversing diabetes-induced hyperacetylation and functional impairments of a cluster of mitochondrial enzymes. FGF21 prevented toxic lipids-induced mitochondrial dysfunction and oxidative stress by induction of the AMPK/FOXO3/SIRT3 signaling axis in human induced pluripotent stem cell-derived cardiomyocytes. Adeno-associated virus-mediated restoration of cardiac SIRT3 expression was sufficient to restore the responsiveness of diabetic FGF21 knockout mice to exercise in amelioration of mitochondrial dysfunction and DCM. CONCLUSIONS: The FGF21-SIRT3 axis mediates the protective effects of exercise against DCM by preserving mitochondrial integrity and represents a potential therapeutic target for DCM. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03240978.

Hepatic PRMT1 ameliorates diet-induced hepatic steatosis via induction of PGC1α.

Rationale: Over-nutrition will lead to overexpression of PRMT1 but protein hypomethylation is observed in the liver of obese subjects. The dynamic alteration of the expression and methyltransferase activity of PRMT1 in the progression of fatty liver diseases remains elusive. Methods: We used recombinant adeno-associated virus-mediated gene delivery system to manipulate the hepatic PRMT1 expression level in diet-induced obese mice to investigate the role of PRMT1 in hepatic steatosis. We further utilized a cohort of obese humans with biopsy-proven nonalcoholic fatty liver disease to support our observations in mouse model. Results: We demonstrated that knockdown of PRMT1 promoted steatosis development in liver of high-fat diet (HFD) fed mice. Over-expression of wild-type PRMT1, but not methyltransferase-defective mutant PRMT1G80R, could alleviate diet-induced hepatic steatosis. The observation is conserved in the specimens of obese humans with biopsy-proven nonalcoholic fatty liver disease. Mechanistically, methyltransferase activity of PRMT1 was required to induce PGC-1α mRNA expression via recruitment of HNF-4α to the promoter of PGC-1α, and hence attenuated HFD-induced hepatic steatosis by enhancing PGC-1α-mediated fatty acid oxidation. Conclusions: Our results identify that activation of the PRMT1/HNF-4α/PGC-1α signaling is a potential therapeutic strategy for combating non-alcoholic fatty liver disease of obese subjects.

PM20D1 is a circulating biomarker closely associated with obesity, insulin resistance and metabolic syndrome.

OBJECTIVE: Peptidase M20 domain containing 1 (PM20D1), a secreted enzyme catalysing condensation of fatty acids and amino acids into the bioactive lipids N-acyl amino acids (NAAA), induces uncoupling protein 1 (UCP1)-independent adaptive thermogenesis in brown/beige adipocytes in mice. This study aimed to explore the associations of the circulating levels of PM20D1 and major NAAA with obesity-related metabolic complications in humans. DESIGN AND METHODS: Serum concentrations of PM20D1 and NAAA (C18:1-Leu and C18:1-Phe) in 256 Chinese subjects, including 78 lean and 178 overweight/obese individuals with or without diabetes, were measured with immunoassays and liquid chromatography-mass spectrometry, respectively. The impact of sulfonylurea and rosiglitazone on their circulating levels was examined in 62 patients with type 2 diabetes. RESULTS: Serum PM20D1 level was significantly elevated in overweight/obese individuals and was closely associated with circulating levels of C18:1-Leu and C18:1-Phe. Furthermore, serum PM20D1, C18:1-Leu and C18:1-Phe concentrations correlated positively with several parameters of adiposity as well as fasting and 2 h postprandial glucose, HbA1c, fasting insulin and HOMA-IR independent of BMI and age. Moreover, a significant elevation in PM20D1, C18:1-Leu and C18:1-Phe concentrations corresponding with increases in the number of components of the metabolic syndrome (MetS) was observed. Treatment with sulfonylurea significantly decreased circulating PM20D1, C18:1-Leu and C18:1-Phe in patients with type 2 diabetes. CONCLUSIONS: Increased serum levels of PM20D1 and its catalytic products NAAA are closely associated with obesity-related glucose dysregulation, insulin resistance and MetS and can be potentially used as clinical biomarkers for diagnosing and monitoring these disorders.

Ginsenoside Rb1 Improves Cognitive Impairment Induced by Insulin Resistance through Cdk5/p35-NMDAR-IDE Pathway.

The relationship between diabetes mellitus (DM) and Alzheimer's disease (AD) has attracted wide attention. Studies have reported that ginsenoside Rb1 can improve human cognitive ability and glucose tolerance during the development of diabetes. The mechanism behind the improvement in cognitive ability and glucose tolerance still remains unclear. In this study, streptozotocin- (STZ-) injected mice were used as models to explore the mechanisms behind the cognitive improvement of ginsenoside Rb1. According to the results of behavioral tests, ginsenoside Rb1 improved memory and cognitive ability of STZ-lesioned mice. In addition to that, ginsenoside Rb1 also relieved glucose intolerance induced by STZ injection by enhancing insulin sensitivity. These beneficial effects of ginsenoside Rb1 is most likely mediated by upregulating the expression of NMDAR1 and IDE in the hippocampus through inhibiting the activity of Cdk5/p35. This work will be of great importance in illustrating the mechanisms of ginsenoside Rb1 for improving cognitive ability, as well as revealing the relationship between diabetes and AD.

Omethoate induces pharyngeal cancer cell proliferation and G1/S cell cycle progression by activation of Akt/GSK-3ß/cyclin D1 signaling pathway.

Omethoate is a broad category of organophosphorous pesticides (OPs) and has toxic effects on human health under long-term, low-dose exposure. However, the role of omethoate in cancer development remains elusive. The incidence of global head and neck squamous cell carcinomas (HNSCC) has markedly increased in recent years. Thus, we examined whether omethoate induced the proliferation of FaDu cells (a cell line of HNSCC) and if so, what the underlying mechanism was. The study revealed that omethoate induced FaDu cell growth in a dose- and time-dependent manner. Omethoate stimulated FaDu cell proliferation was mainly due to enhancing the G1 to S phase transition by flow cytometry analysis. We also found that omethoate up-regulated cyclin D1, a key gene controlling the G1-S transition. Furthermore, we showed that omethoate was capable of activating the Akt/GSK-3ß signaling pathway. Blockage of Akt by siRNA or small molecule inhibitor significantly suppressed omethoate-induced cyclin D1 expression and cell proliferation. Collectively, these findings demonstrated for the first time that omethoate could induce the pharyngeal cancer cell proliferation by activation of the Akt/GSK-3ß/cyclin D1 signaling pathway.

DL0410, a novel dual cholinesterase inhibitor, protects mouse brains against Aß-induced neuronal damage via the Akt/JNK signaling pathway.

AIM: 1,1'-([1,1'-Biphenyl]-4,4'-diyl)bis(3-(piperidin-1-yl)propan-1-one)dihydrochloride (DL0410) is a novel synthetic dual acetylcholinesterase (AChE)/butyrocholinesterase (BuChE) inhibitor, which has shown a potential therapeutic effect on Alzheimer's disease (AD). In this study we examined whether DL0410 produced neuroprotective effects in an AD cellular model and an Aß1-42-induced amnesia mouse model. METHODS: The in vitro inhibitory activities against AChE and BuChE were estimated using Ellman's assay. Copper-induced toxicity in APPsw-SY5Y cells was used as AD cellular model, the cell viability was assessed using MTS assay, and cell apoptosis was evaluated based on mitochondrial membrane potential detection. Aß1-42-induced amnesia mouse model was made in male mice by injecting aggregated Aß1-42 (2 µg in 2 µL 0.1% DMSO) into the right cerebral ventricle. Before and after Aß1-42 injection, the mice were orally administered DL0410 (1, 3, 9 mg·kg-1·d-1) or rivastigmine (2 mg·kg-1·d-1) for 3 and 11 d, respectively. Memory impairments were examined using Morris water maze (MWM) test and passive avoidance test. The expression levels of APP, CREB, BDNF, JNK and Akt in the mouse brains were measured with either immunohistochemistry or Western blotting. RESULTS: DL0410 exhibited in vitro inhibitory abilities against AChE and BuChE with IC50 values of 0.286±0.004 and 3.962±0.099 µmol/L, respectively, which were comparable to those of donepezil and rivastigmine. In APPsw-SY5Y cells, pretreatment with DL0410 (1, 3, and 10 µmol/L) decreased the phosphorylation of JNK and increased the phosphorylation of Akt, markedly decreased copper-stimulated Aß1-42 production, reversed the loss of mitochondrial membrane potential, and dose-dependently increased the cell viability. In Aß1-42-treated mice, DL0410 administration significantly ameliorated learning and memory deficits in MWM test and passive avoidance test. Furthermore, DL0410 administration markedly decreased Aß1-40/42 deposits in mouse cerebral cortices, and significantly up-regulated neurotrophic CREB/BDNF. Meanwhile, Akt/JNK signaling pathway may play a key role in the neuroprotective effect of DL0410. CONCLUSION: DL0410 ameliorates cognitive deficit and exerts neuronal protection in AD models, implicating this compound as a candidate drug for the prevention and therapy of AD.

Chronic stress and excessive glucocorticoid exposure both lead to altered Neuregulin-1/ErbB signaling in rat myocardium.

Exposure to chronic stress or excess glucocorticoids is associated with the development of depression and heart disease, but the underlying mechanisms remain equivocal. While recent evidence has indicated that Neuregulin-1 (NRG1) and its ErbB receptors play an essential role in cardiac function, much is still unknown concerning the biological link between NRG1/ErbB pathway and the stress-induced comorbidity of depression and cardiac dysfunction. Therefore, we examined the protein expression of NRG1 and ErbB receptors in the myocardium of rats following chronic unpredictable mild stress (CUMS) or rats treated with two different doses (0.2 and 2mg/kg/day, respectively) of dexamethasone (Dex). The stressed rats showed elevated expression of NRG1 and phosphorylated ErbB4 (pErbB4) in the myocardium, whereas ErbB2 and pErbB2 were inhibited. The lower dose of Dex enhanced myocardial NRG1/ErbB signaling, but as the dose is increased, while ErbB4 remained activated, the expression of ErbB2 and pErbB2 became compromised. Both CUMS and 2mg/kg of Dex suppressed the downstream Akt and ERK phosphorylation. Although the lower dose of Dex increased myocardial antiapoptotic Bcl-xl expression, a significant decrease of Bcl-xl expression was found in rats treated with the higher dose. Meanwhile, both CUMS and two different doses of Dex induced proapoptotic Bax level. Combined, our data firstly showed (mal)adaptive responses of NRG1/ErbB system in the stressed heart, indicating the potential involvement of NRG1/ErbB pathway in the stress-induced cardiac dysfunction.

Chronic administration of calcitriol enhanced neuregulin-1/ErbB signaling in rat myocardium.

Although emerging evidence suggests that vitamin D has beneficial effects in the cardiovascular health, the underlying mechanisms are far from fully elucidated. Given the indispensable role of neuregulin-1 (NRG1)/ErbB signaling in the cardiovascular system, the present study investigated the influences of prolonged administration of calcitriol, the active form of vitamin D, on the NRG1/ErbB system. We examined the protein expression of NRG1, ErbB receptors (ErbB2 and ErbB4) and their phosphorylated forms in the myocardium of rats following 6-week administration of calcitriol (50 ng/kg/day or 100 ng/kg/day). We further assessed the myocardial vitamin D receptor (VDR) to confirm the effect of calcitriol treatment. Additionally, serum neuregulin-1 level was also analyzed. Generally, calcitriol enhanced myocardial VDR expression and NRG1/ErbB signaling. Calcitriol increased NRG1 protein level at the higher dose, while both doses promoted ErbB2 and phosphorylated ErbB2 expression. Although calcitriol has no significant influence on ErbB4 expression, phosphorylated ErbB4 receptors were enhanced at the higher dose. Furthermore, the serum neuregulin-1 concentration was increased at both doses. Overall, our data firstly showed that chronic calcitriol administration enhanced NRG1/ErbB signaling in the heart, indicating a novel mechanism underlying the cardiac effects of vitamin D.

Quantitative profiling of neurotransmitter abnormalities in the hippocampus of rats treated with lipopolysaccharide: Focusing on kynurenine pathway and implications for depression.

Peripheral administration of lipopolysaccharide (LPS) can induce the rodents to a depression-like state accompanied with remarkable changes of neurotransmitter systems. In this study, the effect of an intraperitoneal LPS injection (3mg/kg) on the concentrations of neurotransmitters was investigated by in vivo microdialysis in rat hippocampus. To further explore dysregulation pattern of the neurotransmitters following continuous inflammatory process, we then analyzed the neurotransmitters in the hippocampus of rats after 2-week LPS exposure (500µg/kg every other day). Acute treatment of LPS quickly enhanced glutamate release and increased the extracellular levels of dopamine, serotonin and their metabolites. Elevated glutamate status was also found in the chronic inflamed hippocampus, whereas dopamine and serotonin was decreased following prolonged LPS exposure. Interestingly, both acute and chronic treatment of LPS significantly elevated hippocampal kynurenine concentrations and altered the balance between the serotonin and kynurenine branches of tryptophan metabolism-increasing kynurenine/tryptophan ratio, but decreasing serotonin/tryptophan ratio. Additionally, kynurenic acid, the endogenous NMDA receptor antagonist, and the ratio of kynurenic acid/kynurenine were significantly decreased by acute treatment of LPS, which may further strengthen NMDA receptor activation. Since that NMDA activation can exacerbate inflammatory and neurodegenerative process, the enhanced glutamate release and dysregulated kynurenine pathway might constitute a vicious cycle playing a pivotal role in the neuropsychiatric disorders associated with inflammation, such as depression.

Effects of prolonged antipsychotic administration on neuregulin-1/ErbB signaling in rat prefrontal cortex and myocardium: implications for the therapeutic action and cardiac adverse effect.

Patients with schizophrenia (SCZ) are at higher risk for developing cardiovascular disease (CVD) and neuregulin-1 (NRG1)/ErbB signaling has been identified as a common susceptibility pathway for the comorbidity. Antipsychotic treatment can change NRG1/ErbB signaling in the brain, which has been implicated in their therapeutic actions, whereas the drug-induced alterations of NRG1/ErbB pathway in cardiovascular system might be associated with the prominent cardiac side-effects of antipsychotic medication. To test this hypothesis, we examined NRG1/ErbB system in rat prefrontal cortex (PFC) and myocardium following 4-week intraperitoneal administration of haloperidol, risperidone or clozapine. Generally, the antipsychotics significantly enhanced NRG1/ErbB signaling with increased expression of NRG1 and phosphorylation of ErbB4 and ErbB2 in the brain and myocardium, except that clozapine partly blocked the cardiac NRG1/ErbB2 activation, which could be associated with its more severe cardiac adverse actions. Combined, our data firstly showed evidence of the effect of antipsychotic exposure on myocardial NRG1/ErbB signaling, along with the activated NRG1/ErbB system in brain, providing a potential link between the therapeutic actions and cardiotoxicity.

Dysregulation of Neuregulin-1/ErbB signaling in the prefrontal cortex and hippocampus of rats exposed to chronic unpredictable mild stress.

Exposure to chronic stress increases the likelihood of developing depression, but the underlying mechanisms remain equivocal. While recent evidence has indicated that Neuregulin-1 (NRG1) and its ErbB receptors play an essential role in neural development and function, and NRG1 has emerged as a novel modulator involved in the response of brain to stress, there is limited evidence concerning the effects of chronic stress exposure on NRG1/ErbB signaling. To fill this critical gap, we examined the protein expression of NRG1 and ErbB receptors in the brain of rats following chronic unpredictable mild stress (CUMS) exposure. After 6weeks of CUMS procedures, the rats were induced to a depression-like state. The stressed rats displayed elevated expression of NRG1 and phosphorylated ErbB4 (pErbB4) in the prefrontal cortex, whereas ErbB2 and pErbB2 were inhibited. In the hippocampus, CUMS also attenuated activation of the both ErbB receptors and suppressed the downstream Akt and ERK phosphorylation. Meanwhile, administration of sertraline enhanced NRG1/ErbB signaling and partly normalized the stress-induced behavioral changes and the disturbances of NRG1/ErbB system in CUMS rats. Combined, our data firstly showed the aberrant changes of NRG1/ErbB system in the brain of the animal model of depression, providing new evidence for the involvement of NRG1/ErbB pathway in the development and treatment of depression.

DL0410 can reverse cognitive impairment, synaptic loss and reduce plaque load in APP/PS1 transgenic mice.

Cholinesterase inhibitors are first-line therapy for Alzheimer's disease (AD). DL0410 is an AChE/BuChE dual inhibitor with a novel new structural scaffold. It has been demonstrated that DL0410 could improve memory deficits in both Aß1-42-induced and scopolamine-induced amnesia in mice. In the present study, the therapeutic effect of DL0410 and its action mechanism were investigated in APP/PS1 transgenic mice. Six-month old APP/PS1 transgenic mice were orally administered with DL0410 (3, 10, 30 mg/kg/day). After 60 days, several behavioural tests, including the Morris water maze and step-down tests, were used to investigate the effects of DL0410 on mice behaviours. All the behavioural experimental results showed that DL0410 significantly ameliorated memory deficits. Meanwhile, DL0410 attenuated neural cell damage and reduced senile plaques significantly in the hippocampus of APP/PS1 transgenic mice. In addition, DL0410 significantly decreased Aß plaques, while increasing the number of synapses and the thickness of PSD in the hippocampus. We also found DL0410 decreased the expression of APP, NMDAR1B and the phosphorylation level of NMDAR2B, and increased the phosphorylation level of CAMKII and the expression of PSD-95. In this study, the results of behavioural tests demonstrated for the first time that DL0410 could improve learning and memory dysfunction in APP/PS1 transgenic mice. The mechanism of its beneficial effects might be related to cholinesterase inhibition, Aß plaques inhibition, improvement of synapse loss by regulating of expression of proteins related to synapses. As a result, DL0410 could be considered as a candidate drug for the therapy of AD.

Ameliorative effects of baicalein in MPTP-induced mouse model of Parkinson's disease: A microarray study.

Baicalein, a flavonoid from Scutellaria baicalensis Georgi, has been shown to possess neuroprotective properties. The purpose of this study was to explore the effects of baicalein on motor behavioral deficits and gene expression in N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mice model of Parkinson's disease (PD). The behavioral results showed that baicalein significantly improves the abnormal behaviors in MPTP-induced mice model of PD, as manifested by shortening the total time for climbing down the pole, prolonging the latent periods of rotarod, and increasing the vertical movements. Using cDNA microarray and subsequent bioinformatic analyses, it was found that baicalein significantly promotes the biological processes including neurogenesis, neuroblast proliferation, neurotrophin signaling pathway, walking and locomotor behaviors, and inhibits dopamine metabolic process through regulation of gene expressions. Based on analysis of gene co-expression networks, the results indicated that the regulation of genes such as LIMK1, SNCA and GLRA1 by baicalein might play central roles in the network. Our results provide experimental evidence for the potential use of baicalein in the treatment of PD, and revealed gene expression profiles, biological processes and pathways influenced by baicalein in MPTP-treated mice.

Consensus models for CDK5 inhibitors in silico and their application to inhibitor discovery.

Cyclin-dependent kinase 5 (CDK5) has emerged as a principal therapeutic target for Alzheimer's disease. It is highly desirable to develop computational models that can predict the inhibitory effects of a compound towards CDK5 activity. In this study, two machine learning tools (naive Bayesian and recursive partitioning) were used to generate four single classifiers from a large dataset containing 462 CDK5 inhibitors and 1,500 non-inhibitors. Then, two types of consensus models [combined classifier-artificial neural networks (CC-ANNs) and consensus prediction] were applied to combine four single classifiers to obtain superior performance. The results showed that both consensus models outperformed four single classifiers, and (MCC = 0.806) was superior to consensus prediction (MCC = 0.711) for an external test set. To illustrate the practical applications of the CC-ANN model in virtual screening, an in-house dataset containing 29,170 compounds was screened, and 40 compounds were selected for further bioactivity assays. The assay results showed that 13 out of 40 compounds exerted CDK5/p35 inhibitory activities with IC50 values ranging from 9.23 to 229.76 µM. Interestingly, three new scaffolds that had not been previously reported as CDK5 inhibitors were found in this study. These studies prove that our protocol is an effective approach to predict small-molecule CDK5 affinity and identify novel lead compounds.

Discovery of multitarget-directed ligands against Alzheimer's disease through systematic prediction of chemical-protein interactions.

To determine chemical-protein interactions (CPI) is costly, time-consuming, and labor-intensive. In silico prediction of CPI can facilitate the target identification and drug discovery. Although many in silico target prediction tools have been developed, few of them could predict active molecules against multitarget for a single disease. In this investigation, naive Bayesian (NB) and recursive partitioning (RP) algorithms were applied to construct classifiers for predicting the active molecules against 25 key targets toward Alzheimer's disease (AD) using the multitarget-quantitative structure-activity relationships (mt-QSAR) method. Each molecule was initially represented with two kinds of fingerprint descriptors (ECFP6 and MACCS). One hundred classifiers were constructed, and their performance was evaluated and verified with internally 5-fold cross-validation and external test set validation. The range of the area under the receiver operating characteristic curve (ROC) for the test sets was from 0.741 to 1.0, with an average of 0.965. In addition, the important fragments for multitarget against AD given by NB classifiers were also analyzed. Finally, the validated models were employed to systematically predict the potential targets for six approved anti-AD drugs and 19 known active compounds related to AD. The prediction results were confirmed by reported bioactivity data and our in vitro experimental validation, resulting in several multitarget-directed ligands (MTDLs) against AD, including seven acetylcholinesterase (AChE) inhibitors ranging from 0.442 to 72.26 µM and four histamine receptor 3 (H3R) antagonists ranging from 0.308 to 58.6 µM. To be exciting, the best MTDL DL0410 was identified as an dual cholinesterase inhibitor with IC50 values of 0.442 µM (AChE) and 3.57 µM (BuChE) as well as a H3R antagonist with an IC50 of 0.308 µM. This investigation is the first report using mt-QASR approach to predict chemical-protein interaction for a single disease and discovering highly potent MTDLs. This protocol may be useful for in silico multitarget prediction of other diseases.