Tetrahydroalstonine possesses protective potentials on palmitic acid stimulated SK-N-MC cells by suppression of Aß1-42 and tau through regulation of PI3K/Akt signaling pathway.

Alzheimer's disease (AD) is the most common neurodegenerative disease. The morbidity of Alzheimer's disease is currently on the rise worldwide, but no effective treatment is available. Cornus officinalis is an herb and edible plant used in traditional Chinese medicine, whose extract has neuroprotective properties. In this investigation, we endeavored to refine a systems pharmacology strategy combining bioinformatics analysis, drug prediction, network pharmacology, and molecular docking to screen tetrahydroalstonine (THA) from Cornus officinalis as a therapeutic component for AD. Subsequent in vitro experiments were validated using MTT assay, Annexin V-PI flow cytometry, Western blotting, and immunofluorescence analysis. In Palmitate acid-induced SK-N-MC cells, THA restored the impaired PI3K/AKT signaling pathway, regulated insulin resistance, and attenuated BACE1 and GSK3ß activity. In addition, THA significantly reduced cell apoptosis rate, down-regulated relative levels of p-JNK/JNK, Bax/Bcl-2, cytochrome C, active caspase-3 and caspase-3, and attenuated Palmitate acid-induced Aß1-42 and Tau generation. THA may regulate the phenotype of AD and reduce cell apoptosis by modulating the PI3K/AKT signaling pathway. This systematic analysis provides new ramifications concerning the therapeutic utility of tetrahydroalstonine for AD.

Agomelatine improves memory and learning impairments in a rat model of LPS-induced neurotoxicity by modulating the ERK/SorLA/BDNF/TrkB pathway.

The mutual interplay between neuroinflammation, synaptic plasticity, and autophagy has piqued researchers' interest, particularly when it comes to linking their impact and relationship to cognitive deficits. Being able to reduce inflammation and apoptosis, melatonin has shown to have positive neuroprotective effects; that is why we thought to check the possible role of agomelatine (AGO) as a promising candidate that could have a positive impact on cognitive deficits. In the current study, AGO (40 mg/kg/day, p.o., 7 days) successfully ameliorated the cognitive and learning disabilities caused by lipopolysaccharide (LPS) in rats (250 µg/kg/day, i.p., 7 days). This positive impact was supported by improved histopathological findings and improved spatial memory as assessed using Morris water maze. AGO showed a strong ability to control BACE1 activity and to rein in the hippocampal amyloid beta (Aß) deposition. Also, it improved neuronal survival, neuroplasticity, and neurogenesis by boosting BDNF levels and promoting its advantageous effects and by reinforcing the pTrkB expression. In addition, it upregulated the pre- and postsynaptic neuroplasticity biomarkers resembled in synapsin I, synaptophysin, and PSD-95. Furthermore, AGO showed a modulatory action on Sortilin-related receptor with A-type repeats (SorLA) pathway and adjusted autophagy. It is noteworthy that all of these actions were abolished by administering PD98059 a MEK/ERK pathway inhibitor (0.3 mg/kg/day, i.p., 7 days). In conclusion, AGO administration significantly improves memory and learning disabilities associated with LPS administration by modulating the ERK/SorLA/BDNF/TrkB signaling pathway parallel to its capacity to adjust the autophagic process.

Should evidence of an autolysosomal de-acidification defect in Alzheimer and Parkinson diseases call for caution in prescribing chronic PPI and DMARD?

Nearly fifty million older people suffer from neurodegenerative diseases, including Alzheimer (AD) and Parkinson (PD) disease, a global burden expected to triple by 2050. Such an imminent "neurological pandemic" urges the identification of environmental risk factors that are hopefully avoided to fight the disease. In 2022, strong evidence in mouse models incriminated defective lysosomal acidification and impairment of the autophagy pathway as modifiable risk factors for dementia. To date, the most prescribed lysosomotropic drugs are proton pump inhibitors (PPIs), chloroquine (CQ), and the related hydroxychloroquine (HCQ), which belong to the group of disease-modifying antirheumatic drugs (DMARDs). This commentary aims to open the discussion on the possible mechanisms connecting the long-term prescribing of these drugs to the elderly and the incidence of neurodegenerative diseases.Abbreviations: AD: Alzheimer disease; APP-ßCTF: amyloid beta precursor protein-C-terminal fragment; BACE1: beta-secretase 1; BBB: brain blood barrier; CHX: Ca2+/H+ exchanger; CMI: cognitive mild impairment; CQ: chloroquine; DMARD: disease-modifying antirheumatic drugs; GBA1: glucosylceramidase beta 1; HCQ: hydroxychloroquine; HPLC: high-performance liquid chromatography; LAMP: lysosomal associated membrane protein; MAPK/JNK: mitogen-activated protein kinase; MAPT: microtubule associated protein tau; MCOLN1/TRPML1: mucolipin TRP cation channel 1; NFE2L2/NRF2: NFE2 like bZIP transcription factor 2; NRBF2: nuclear receptor binding factor 2; PANTHOS: poisonous flower; PD: Parkinson disease; PIK3C3: phosphatIdylinositol 3-kinase catalytic subunit type 3; PPI: proton pump inhibitor; PSEN1: presenilin 1, RUBCN: rubicon autophagy regulator; RUBCNL: rubicon like autophagy enhancer; SQSTM1: sequestosome 1; TMEM175: transmembrane protein 175; TPCN2: two pore segment channel 2; VATPase: vacuolar-type H+-translocating ATPase; VPS13C: vacuolar protein sorting ortholog 13 homolog C; VPS35: VPS35 retromer complex component; WDFY3: WD repeat and FYVE domain containing 3; ZFYVE1: zinc finger FYVE-type containing 1.

Leptin Signaling Could Mediate Hippocampal Decumulation of Beta-Amyloid and Tau Induced by High-Intensity Interval Training in Rats with Type 2 Diabetes.

Leptin (LEP) can cross the blood-brain barrier and facilitate cross-talk between the adipose tissue and central nerve system (CNS). This study aimed to investigate the effect of 8-week high-intensity interval training (HIIT) on the LEP signaling in the hippocampus of rats with type 2 diabetes. 20 rats were randomly divided into four groups: (i) control (Con), (ii) type 2 diabetes (T2D), (iii) exercise (EX), and (iv) type 2 diabetes + exercise (T2D + EX). The rats in the T2D and T2D + EX were fed a high-fat diet for two months, then a single dose of STZ (35 mg/kg) was injected to induce diabetes. The EX and T2D + EX groups performed 4-10 intervals of treadmill running at 80-100% of Vmax. Serum and hippocampal levels of LEP as well as hippocampal levels of LEP receptors (LEP-R), Janus kinase 2 (JAK-2), signal transducer and activator of transcription 3 (STAT-3), activated protein kinase (AMP-K), proxy zoster receptor α (PGC-1α), beta-secretase 1 (BACE1), Beta-Amyloid (Aß), Phosphoinositide 3-kinases (PI3K), protein kinase B (AKT), mammalian target of rapamycin (mTOR), Glycogen Synthase Kinase 3 Beta (GSK3ß), and hyperphosphorylated tau proteins (TAU) were measured. One-way ONOVA and Tukey post-hoc tests were used to analyze the data. Serum and hippocampal levels of LEP as well as hippocampal levels of LEP-R, JAK-2, STAT-3, AMP-K, PGC1α, PI3K, AKT, and mTOR were increased while hippocampal levels of BACE1, GSK3B, TAU, and Aß were decreased in T2D + EX compared with T2D group. Serum LEP and hippocampal levels of LEP, LEP-R, JAK-2, STAT-3, AMP-K, PGC1α, PI3K, AKT, and mTOR were decreased. Conversely hippocampal levels of BACE1, GSK3B, TAU, and Aß were increased in T2D group compared with CON group. HIIT could improve LEP signaling in the hippocampus of rats with type 2 diabetes and decrease the accumulation of Tau and Aß, which may reduce the risk of memory impairments.

Inhibition of NLRP1 inflammasome improves autophagy dysfunction and Aß disposition in APP/PS1 mice.

Increasing evidence has shown that the NOD-like receptor protein 1 (NLRP1) inflammasome is associated with Aß generation and deposition, which contributes to neuronal damage and neuronal-inflammation in Alzheimer's disease (AD). However, the specific mechanism of NLRP1 inflammasome in the pathogenesis of AD is still unclear. It has been reported that autophagy dysfunction can aggravate the pathological symptoms of AD and plays an important role in regulating Aß generation and clearance. We hypothesized that NLRP1 inflammasome activation may induce autophagy dysfunction contributing to the progression of AD. In the present study, we observed the relationship between Aß generation and NLRP1 inflammasome activation, as well as AMPK/mTOR mediated-autophagy dysfunction in WT 9-month-old (M) mice, APP/PS1 6 M and APP/PS1 9 M mice. Additionally, we further studied the effect of NLRP1 knockdown on cognitive function, Aß generation, neuroinflammation and AMPK/mTOR mediated autophagy in APP/PS1 9 M mice. Our results indicated that NLRP1 inflammasome activation and AMPK/mTOR mediated-autophagy dysfunction are closely implicated in Aß generation and deposition in APP/PS1 9 M mice, but not in APP/PS1 6 M mice. Meanwhile, we found that knockdown of NLRP1 significantly improved learning and memory impairments, decreased the expressions of NLRP1, ASC, caspase-1, p-NF-κB, IL-1ß, APP, CTF-ß, BACE1 and Aß1-42, and decreased the level of p-AMPK, Beclin 1 and LC3 II, and increased the level of p-mTOR and P62 in APP/PS1 9 M mice. Our study suggested that inhibition of NLRP1 inflammasome activation improves AMPK/mTOR mediated-autophagy dysfunction, resulting in the decrease of Aß generation, and NLRP1 and autophagy might be important targets to delay the progression of AD.

Vitamin D alleviates cognitive dysfunction and brain damage induced by copper sulfate intake in experimental rats: focus on its combination with donepezil.

This study aimed to demonstrate the potential benefits of donepezil (DPZ) and vitamin D (Vit D) in combination to counteract the neurodegenerative disorders induced by CuSO4 intake in experimental rats. Neurodegeneration (Alzheimer-like) was induced in twenty-four male Wistar albino rats by CuSO4 supplement to drinking water (10 mg/L) for 14 weeks. AD rats were divided into four groups: untreated AD group (Cu-AD) and three treated AD groups; orally treated for 4 weeks with either DPZ (10 mg/kg/day), Vit D (500 IU/kg/day), or DPZ + Vit D starting from the 10th week of CuSO4 intake. Another six rats were used as normal control (NC) group. The hippocampal tissue content of ß-amyloid precursor protein cleaving enzyme 1 (BACE1), phosphorylated Tau (p-tau), clusterin (CLU), tumor necrosis factor-α (TNF-α), caspase-9 (CAS-9), Bax, and Bcl-2 and the cortical content of acetylcholine (Ach), acetylcholinesterase (AChE), total antioxidant capacity (TAC), and malondialdehyde (MDA) were measured. Cognitive function tests (Y-maze) and histopathology studies (hematoxylin and eosin and Congo red stains) and immunohistochemistry for neurofilament. Vit D supplementation alleviated CuSO4-induced memory deficits including significant reduction hippocampal BACE1, p-tau, CLU, CAS-9, Bax, and TNF-α and cortical AChE and MDA. Vit D remarkably increased cortical Ach, TAC, and hippocampal Bcl-2. It also improved neurobehavioral and histological abnormalities. The effects attained by Vit D treatment were better than those attained by DPZ. Furthermore, Vit D boosted the therapeutic potential of DPZ in almost all AD associated behavioral and pathological changes. Vit D is suggested as a potential therapy to retard neurodegeneration.

Hydroxysafflor Yellow A Exerts Neuroprotective Effect by Reducing Aß Toxicity Through Inhibiting Endoplasmic Reticulum Stress in Oxygen-Glucose Deprivation/Reperfusion Cell Model.

Ischemia stroke is thought to be one of the vascular risks associated with neurodegenerative diseases, such as Alzheimer's disease (AD). Hydroxysafflor yellow A (HSYA) has been reported to protect against stroke and AD, while the underlying mechanism remains unclear. In this study, SH-SY5Y cell model treated with oxygen-glucose deprivation/reperfusion (OGD/R) was used to explore the potential mechanism of HSYA. Results from cell counting kit-8 (CCK-8) showed that 10 µM HSYA restored the cell viability after OGD 2 hours/R 24 hours. HSYA reduced the levels of malondialdehyde and reactive oxygen species, while improved the levels of superoxide dismutase and glutathione peroxidase. Furthermore, apoptosis was inhibited, and the expression of brain-derived neurotrophic factor was improved after HSYA treatment. In addition, the expression levels of amyloid-ß peptides (Aß) and BACE1 were decreased by HSYA, as well as the expression levels of binding immunoglobulin heavy chain protein, PKR-like endoplasmic reticulum (ER) kinase pathway, and activating transcription factor 6 pathway, whereas the expression level of protein disulfide isomerase was increased. Based on these results, HSYA might reduce Aß toxicity after OGD/R by interfering with apoptosis, oxidation, and neurotrophic factors, as well as relieving ER stress.

Insulin Signaling Disruption and INF-γ Upregulation Induce Aß1-42 and Hyperphosphorylated-Tau Proteins Synthesis and Cell Death after Paraquat Treatment of Primary Hippocampal Cells.

Acute and long-term paraquat (PQ) exposure produces hippocampal neurodegeneration and cognition decline. Although some mechanisms involved in these effects were found, the rest are unknown. PQ treatment, for 1 and 14 days, upregulated interferon-gamma signaling, which reduced insulin levels and downregulated the insulin pathway through phosphorylated-c-Jun N-terminal-kinase upregulation, increasing glucose levels and the production of Aß1-42 and phosphorylated-tau, by beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) overexpression and phosphorylated-GSK3ß (p-GSK3ß; ser9) level reduction, respectively, which induced primary hippocampal neuronal loss. This novel information on the PQ mechanisms leading to hippocampal neurodegeneration could help reveal the PQ actions that lead to cognition dysfunction.

Stress level of glucocorticoid exacerbates neuronal damage and Aß production through activating NLRP1 inflammasome in primary cultured hippocampal neurons of APP-PS1 mice.

Glucocorticoid (GC), secreted by adrenal cortex, plays important roles in regulating many physiological functions, while chronic stress level of GC exposure has many adverse effects on the structure and function of hippocampal neurons, and is closely implicated to the deterioration of Alzheimer's disease (AD). Oxidative stress and neuroinflammation play an important role in the occurrence and development of AD. However, it is still unclear whether chronic GC exposure promotes beta-amyloid (Aß) accumulation and neuronal injury by increasing oxidative stress and neuroinflammation. In this study, we investigated the effects of chronic GC exposure on NOX2-NLRP1 inflammasome activation and the protective effects of NLRP1-siRNA against GC-induced neuronal injury in primary hippocampal neurons of APP/PS1 mice. The results showed that chronic dexamethasone (DEX, 1 µM) exposure 72 h had no significant effect on the primary hippocampal neurons of WT mice, but significantly increased Aß1-42 accumulation (2.17 ± 0.19 fold in APP group and 3.06 ± 0.49 fold in APP + DEX group over WT group) and neuronal injury in primary hippocampal neurons of APP/PS1 mice. Meanwhile, chronic DEX exposure significantly increased the levels of reactive oxygen species (ROS) production and IL-1ß, and significantly up-regulated the expressions of NOX2- and NLRP1-related proteins and mRNAs in primary hippocampal neurons of APP/PS1 mice but not in WT mice. Moreover, inhibition of NLRP1 by NLRP1-siRNA treatment also significantly alleviated neuronal injury and Aß1-42 accumulation (1.96 ± 0.11 fold in APP + DEX group and 0.25 ± 0.01 fold in APP + NLRP1-siRNA + DEX group over APP group), and down-regulated the expressions of APP, BACE1, NCSTN and p-TAU/TAU in chronic DEX-induced hippocampal neurons of APP/PS1 mice. The results suggest that chronic GC exposure can accelerate neuronal damage and Aß production by activating oxidative stress and NLRP1 inflammasome in primary hippocampal neurons of APP/PS1 mice, resulting in deterioration of AD.And inhibition of NLRP1 inflammasome may be an important strategy in improving chronic GC-induced neuronal injury.

Intranasal Delivery of BACE1 siRNA and Rapamycin by Dual Targets Modified Nanoparticles for Alzheimer's Disease Therapy.

Alzheimer's disease (AD), as a progressive and irreversible brain disorder, remains the most universal neurodegenerative disease. No effective therapeutic methods are established yet due to the hindrance of the blood-brain barrier (BBB) and the complex pathological condition of AD.  Therefore, a multifunctional nanocarrier (Rapa@DAK/siRNA) for AD treatment is constructed to achieve small interfering RNA of ß-site precursor protein (APP) cleaving enzyme-1 (BACE1 siRNA) and rapamycin co-delivery into the brain, based on Aleuria aurantia lectin (AAL) and ß-amyploid (Aß)-binding peptides (KLVFF) modified PEGylated dendrigraft poly-l-lysines (DGLs) via intranasal administration. Nasal administration provides an effective way to deliver drugs directly into the brain through the nose-to-brain pathway. AAL, specifically binding to L-fucose located in the olfactory epithelium, endows Rapa@DAK/siRNA with high brain entry efficiency through intranasal administration. KLVFF peptide as an Aß targeting ligand and aggregation inhibitor enables nanoparticles to bind with Aß, inhibit Aß aggregation, and reduce toxicity. Meanwhile, the release of BACE1 siRNA and rapamycin is confirmed to reduce BACE1 expression, promote autophagy, and reduce Aß deposition. Rapa@DAK/siRNA is verified to improve the cognition of transgenic AD mice after intranasal administration. Collectively, the multifunctional nanocarrier provides an effective and potential intranasal avenue for combination therapy of AD.

Long noncoding RNA BACE1-antisense transcript plays a critical role in Parkinson's disease via microRNA-214-3p/Cell death-inducing p53-target protein 1 axis.

This study aimed to analyze the function and latent mechanism of long noncoding RNA BACE1-antisense transcript (lncRNA BACE1-AS) in MPP+-induced SH-SY5Y cells. SH-SY5Y cells were cultivated in 1 mM MPP+ for 24 h to establish Parkinson's disease (PD) model in vitro. TargetScan and luciferase reporter assay were conducted to predict and verify the interaction between microRNA (miR)-214-3p and CDIP1 (Cell death-inducing p53-target protein 1). Cell viability, lactate dehydrogenase (LDH) release, and cell apoptosis were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2 H-tetrazolium bromide (MTT), LDH, and flow cytometer. The secretion of inflammatory factors and representative biomarkers of oxidative stress, including reactive oxygen species (ROS) and superoxide dismutase (SOD) were assessed using enzyme-linked immunosorbent assay (ELISA) and specific assay kits. Results suggested that lncRNA BACE1-AS was over-expressed and miR-214-3p was under-expressed in MPP+-stimulated SH-SY5Y cells. Further analyses revealed that MPP+ inhibited cell viability; enhanced cell apoptosis, Cleaved Caspase-3 expression and Cleaved Caspase-3/GAPDH ratio; induced oxidative stress and inflammation in SH-SY5Y cells were inhibited by lncRNA BACE1-AS-siRNA transfection; and all these inhibitions were reversed by miR-214-3p inhibitor. In addition, we found that CDIP1 was directly targeted by miR-214-3p and up-regulated in MPP+-stimulated SH-SY5Y cells. Further functional assays suggested that CDIP1-plasmid reversed the effects of miR-214-3p mimic on MPP+-stimulated SH-SY5Y cells. In conclusion, lncRNA BACE1-AS regulates SH-SY5Y cell proliferation, apoptosis, inflammatory response, and oxidative stress through direct regulation of miR-214-3p/CDIP1 signaling axis, and could be a potential candidate associated with the diagnosis and treatment of PD.

Dapagliflozin as an autophagic enhancer via LKB1/AMPK/SIRT1 pathway in ovariectomized/D-galactose Alzheimer's rat model.

Autophagy and mitochondrial deficits are characteristics of early phase of Alzheimer's disease (AD). Sodium-glucose cotransporter-2 inhibitors have been nominated as a promising class against AD hallmarks. However, there are no available data yet to discuss the impact of gliflozins on autophagic pathways in AD. Peripherally, dapagliflozin's (DAPA) effect is mostly owed to autophagic signals. Thus, the goal of this study is to screen the power of DAPA centrally on LKB1/AMPK/SIRT1/mTOR signaling in the ovariectomized/D-galactose (OVX/D-Gal) rat model. Animals were arbitrarily distributed between 5 groups; the first group undergone sham operation, while remaining groups undergone OVX followed by D-Gal (150 mg/kg/day; i.p.) for 70 days. After 6 weeks, the third, fourth, and fifth groups received DAPA (1 mg/kg/day; p.o.); concomitantly with the AMPK inhibitor dorsomorphin (DORSO, 25 µg/rat, i.v.) in the fourth group and the SIRT1 inhibitor EX-527 (10 µg/rat, i.v.) in the fifth group. DAPA mitigated cognitive deficits of OVX/D-Gal rats, as mirrored in neurobehavioral task with hippocampal histopathological examination and immunohistochemical aggregates of p-Tau. The neuroprotective effect of DAPA was manifested by elevation of energy sensors; AMP/ATP ratio and LKB1/AMPK protein expressions along with autophagic markers; SIRT1, Beclin1, and LC3B expressions. Downstream the latter, DAPA boosted mTOR and mitochondrial function; TFAM, in contrary lessened BACE1. Herein, DORSO or EX-527 co-administration prohibited DAPA's actions where DORSO elucidated DAPA's direct effect on LKB1 while EX-527 mirrored its indirect effect on SIRT1. Therefore, DAPA implied its anti-AD effect, at least in part, via boosting hippocampal LKB1/AMPK/SIRT1/mTOR signaling in OVX/D-Gal rat model.

Phytol loaded PLGA nanoparticles ameliorate scopolamine-induced cognitive dysfunction by attenuating cholinesterase activity, oxidative stress and apoptosis in Wistar rat.

OBJECTIVE: Alzheimer's disease (AD) is an acquired neurological disorder of cognitive and behavioral impairments, with a long and progressive route. Currently, efforts are being made to develop potent drugs that target multiple pathological mechanisms that drive the successful treatment of AD in human beings. The development of nano-drug delivery systems has recently emerged as an effective strategy to treat AD. METHODS: In the present study, the protective effect of Phytol and Phytol loaded Poly Lactic-co-Glycolic Acid nanoparticles (Phytol-PLGANPs) were evaluated in Wistar rat scopolamine model of AD. RESULTS AND DISCUSSION: The consumption of Phytol and Phytol-PLGANPs significantly ameliorated the cognitive deficits caused by scopolamine on spatial and short term memory. Phytol and Phytol-PLGANPs significantly enhanced the cholinergic effect by inhibiting both acetylcholinesterase and butyrylcholinesterase (AChE & BuChE), ß-secretase 1 (BACE1) activity, attenuating macromolecular damage, reducing reactive oxygen species (ROS) and reactive nitrogen species (RNS) level by activating antioxidative defense system (Superoxide dismutase and catalase) and restoring glutathione metabolizing enzyme systems (Glutathione S-transferase) and also regulating the apoptotic mediated cell death. Moreover, in vivo toxicity study suggests that Phytol and Phytol-PLGANPs did not cause any adverse pathological alteration in rats treated with a higher concentration of Phytol-PLGANPs (200 mg/kg). Pharmacokinetic study revealed that Phytol-PLGANPs enhanced the biodistribution and sustained the release profile of phytol in the brain and plasma. CONCLUSION: Overall, the outcome of the study suggests that Phytol and Phytol-PLGANPs act as a potent candidate with better anti-amnesic effects and multi-faceted neuroprotective potential against scopolamine-induced memory dysfunction in Wistar rats.

Long-term oral administration of hyperoside ameliorates AD-related neuropathology and improves cognitive impairment in APP/PS1 transgenic mice.

Alzheimer's disease (AD) is a highly prevalent neurodegenerative disorder characterized by the pathological hallmarks of ß-amyloid plaque deposits, tau pathology, inflammation, and cognitive decline. Hyperoside, a flavone glycoside isolated from Rhododendron brachycarpum G. Don (Ericaceae), has neuroprotective effects against Aß both in vitro and in vivo. However, whether hyperoside could delay AD pathogenesis remains unclear. In the present study, we observed if chronic treatment with hyperoside can reverse pathological progressions of AD in the APP/PS1 transgenic mouse model. Meanwhile, we attempted to elucidate the molecular mechanisms involved in regulating its effects. After 9 months of treatment, we found that hyperoside can improve spatial learning and memory in APP/PS1 transgenic mice, reduce amyloid plaque deposition and tau phosphorylation, decrease the number of activated microglia and astrocytes, and attenuate neuroinflammation and oxidative stress in the brain of APP/PS1 mice. These beneficial effects may be mediated in part by influencing reduction of BACE1 and GSK3ß levels. Hyperoside confers neuroprotection against the pathology of AD in APP/PS1 mouse model and is emerging as a promising therapeutic candidate drug for AD.

Attenuation of Pb-induced Aß generation and autophagic dysfunction via activation of SIRT1: Neuroprotective properties of resveratrol.

This study examined the neuroprotective properties of resveratrol (Res) and its target sirtuin1 (SIRT1) against lead (Pb)-mediated toxicity and discovered that both resveratrol treatment and SIRT1 overexpression restored blocked autophagic flux as well as reduced ß-amyloid (Aß) contents. Four-week-old male C57BL/6 mice were employed to consumed 0.2% Pb(Ac)2 solution or deionized water for 3 months followed by 12 months of Res (50 mg/kg BW) or vehicle gavage. In in vitro study, SH-SY5Y cells were pretreated with the SIRT1 activator SRT1720 (2 µM) or the inhibitor EX527 (2 µM) for 2 h, then 25 µM of Pb(Ac)2 was added and incubated for 48 h. Western blotting, RT-qPCR, enzyme-linked immunosorbent assay (ELISA), and Lyso-Tracker Red Staining were next used to estimate the potential alterations of the autophagic pathway as well as BACE1-mediated amyloid processing in response to Pb exposure, respectively. Our data revealed that Res treatment or SIRT1 activation resisted the induction of autophagy by Pb exposure through inhibition of LC3 and Beclin-1 expression and promoted the degradation of Aß and Tau phosphorylation. Besides, the SIRT1 activator (SRT1720) downregulated the expression of BACE1, the rate-limiting enzyme for Aß production, by inhibiting the activation of nuclear factor-κB (NF-κB) in Pb-treated SH-SY5Y cells, which resulted in reduced Aß production. Collectively, we verified the role of Res-SIRT1-autophagy as well as the SIRT1-NF-κB-BACE1 pathway in Pb-induced neuronal cell injury by in vivo or in vitro models. Our findings further elucidate the important role of SIRT1 and Res in counteracting Pb neurotoxicity, which may provide new interventions and targets for the subsequent treatment of neurodegenerative diseases.

Standardized production of a homogeneous latex enzyme source overcoming seasonality and microenvironmental variables.

Calotropis procera produces a milky sap containing proteolytic enzymes. At low concentrations, they induce milk-clotting (60 µg/ml) and to dehair hides (0.05 and 0.1%). A protocol for obtaining the enzymes is reported. The latex was mixed with distilled water and the mixture was cleaned through centrifugation. It was dialyzed with distilled water and centrifuged again to recover the soluble fraction [EP]. The dialyze is a key feature of the process. EP was characterized in terms of protein profile, chemical stability, among other criteria. Wild plants belonging to ten geographic regions and grown in different ecological conditions were used as latex source. Collections were carried out, spaced at three-month, according to the seasons at the site of the study. Proteolytic activity was measured as an internal marker and for determining stability of the samples. EP was also analyzed for metal content and microbiology. EP showed similar magnitude of proteolysis, chromatographic and electrophoretic profiles of proteins. Samples stored at 25 °C exhibited reduced solubility (11%) and proteolytic capacity (11%) after six months. Enzyme autolysis was negligible. Microbiological and metal analyses revealed standard quality of all the samples tested. EP induced milk clotting and hide dehairing after storage for up to six months.

Exploiting Structural Dynamics To Design Open-Flap Inhibitors of Malarial Aspartic Proteases.

Malaria is a life-threatening infectious disease caused by Plasmodium parasites. Plasmepsins (proteolytic enzymes of the parasite) have been considered as promising targets for the development of antimalarial drugs. To date, much knowledge has been obtained regarding the interactions of inhibitors with plasmepsins, as well as the structure-activity relationships of the inhibitors. The discovery and characterization of the plasmepsin inhibitors that bind in open flap conformation have led to several inhibitor classes that show high selectivity over other human aspartic proteases. This Perspective addresses the flexibility of the plasmepsins that leads to inhibitor binding to the open flap conformation, summarizes known nonpeptidomimetic plasmepsin inhibitors, and discusses the role of the inhibitor flap pocket substituent.

Inactivation of human kininogen-derived antimicrobial peptides by secreted aspartic proteases produced by the pathogenic yeast Candida albicans.

Ten secreted aspartic proteases (Saps) of Candida albicans cleave numerous peptides and proteins in the host organism and deregulate its homeostasis. Human kininogens contain two internal antimicrobial peptide sequences, designated NAT26 and HKH20. In our current study, we characterized a Sap-catalyzed cleavage of kininogen-derived antimicrobial peptides that results in the loss of the anticandidal activity of these peptides. The NAT26 peptide was effectively inactivated by all Saps, except Sap10, whereas HKH20 was completely degraded only by Sap9. Proteolytic deactivation of the antifungal potential of human kininogens can help the pathogens to modulate or evade the innate immunity of the host.

Partial Molecular Characterization of Arctium minus Aspartylendopeptidase and Preparation of Bioactive Peptides by Whey Protein Hydrolysis.

In this article, we report the cloning of an aspartic protease (AP) from flowers of Arctium minus (Hill) Bernh. (Asteraceae) along with the use of depigmented aqueous flower extracts, as a source of APs, for the hydrolysis of whey proteins. The isolated cDNA encoded a protein product with 509 amino acids called arctiumisin, with the characteristic primary structure organization of typical plant APs. Bovine whey protein hydrolysates, obtained employing the enzyme extracts of A. minus flowers, displayed inhibitory angiotensin-converting enzyme (ACE) and antioxidant activities. Hydrolysates after 3 and 5 h of reaction (degree of hydrolysis 2.4 and 5.6, respectively) and the associated peptide fraction with molecular weight below 3 kDa were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, matrix-assisted laser desorption ionization/time of flight mass spectrometry, and reverse phase-high-performance liquid chromatography. The results obtained in this study demonstrate the viability of using proteases from A. minus to increase the antioxidant and inhibitory ACE capacity of whey proteins.

Tracing binding modes in hit-to-lead optimization: chameleon-like poses of aspartic protease inhibitors.

Successful lead optimization in structure-based drug discovery depends on the correct deduction and interpretation of the underlying structure-activity relationships (SAR) to facilitate efficient decision-making on the next candidates to be synthesized. Consequently, the question arises, how frequently a binding mode (re)-validation is required, to ensure not to be misled by invalid assumptions on the binding geometry. We present an example in which minor chemical modifications within one inhibitor series lead to surprisingly different binding modes. X-ray structure determination of eight inhibitors derived from one core scaffold resulted in four different binding modes in the aspartic protease endothiapepsin, a well-established surrogate for e.g. renin and ß-secretase. In addition, we suggest an empirical metrics that might serve as an indicator during lead optimization to qualify compounds as candidates for structural revalidation.