Astrocyte-derived lactoferrin inhibits neuronal ferroptosis by reducing iron content and GPX4 degradation in APP/PS1 transgenic mice.

Increased astrocytic lactoferrin (Lf) expression was observed in the brains of elderly individuals and Alzheimer's disease (AD) patients. Our previous study revealed that astrocytic Lf overexpression improved cognitive capacity by facilitating Lf secretion to neurons to inhibit ß-amyloid protein (Aß) production in APP/PS1 mice. Here, we further discovered that astrocytic Lf overexpression inhibited neuronal loss by decreasing iron accumulation and increasing glutathione peroxidase 4 (GPX4) expression in neurons within APP/PS1 mice. Furthermore, human Lf (hLf) treatment inhibited ammonium ferric citrate (FAC)-induced ferroptosis by chelating intracellular iron. Additionally, machine learning analysis uncovered a correlation between Lf and GPX4. hLf treatment boosted low-density lipoprotein receptor-related protein 1 (LRP1) internalization and facilitated its interaction with heat shock cognate 70 (HSC70), thereby inhibiting HSC70 binds to GPX4, and eventually attenuating GPX4 degradation and FAC-induced ferroptosis. Overall, astrocytic Lf overexpression inhibited neuronal ferroptosis through two pathways: reducing intracellular iron accumulation and promoting GPX4 expression via inhibiting chaperone-mediated autophagy (CMA)-mediated GPX4 degradation. Hence, upregulating astrocytic Lf expression is a promising strategy for combating AD.

Potential Application Prospects of Biomolecule-Modified Two-Dimensional Chiral Nanomaterials in Biomedicine.

Chirality, one of the most fundamental properties of natural molecules, plays a significant role in biochemical reactions. Nanomaterials with chiral characteristics have superior properties, such as catalytic properties, optoelectronic properties, and photothermal properties, which have significant potential for specific applications in nanomedicine. Biomolecular modifications such as nucleic acids, peptides, proteins, and polysaccharides are sources of chirality for nanomaterials with great potential for application in addition to intrinsic chirality, artificial macromolecules, and metals. Two-dimensional (2D) nanomaterials, as opposed to other dimensions, due to proper surface area, extensive modification sites, drug loading potential, and simplicity of preparation, are prepared and utilized in diagnostic applications, drug delivery research, and tumor therapy. Current advanced studies on 2D chiral nanomaterials for biomedicine are focused on novel chiral development, structural control, and materials sustainability applications. However, despite the advances in biomedical research, chiral 2D nanomaterials still confront challenges such as the difficulty of synthesis, quality control, batch preparation, chiral stability, and chiral recognition and selectivity. This review aims to provide a comprehensive overview of the origins, synthesis, applications, and challenges of 2D chiral nanomaterials with biomolecules as cargo and chiral modifications and highlight their potential roles in biomedicine.

Graphdiyne nanoplatforms for photothermal-ferroptosis combination therapy against glioblastoma.

Glioblastoma (GBM) is one of the most malignant tumors of the central nervous system and has a poor prognosis. GBM cells are highly sensitive to ferroptosis and heat, suggesting thermotherapy-ferroptosis as a new strategy for GBM treatment. With its biocompatibility and photothermal conversion efficiency, graphdiyne (GDY) has become a high-profile nanomaterial. Here, the ferroptosis inducer FIN56 was employed to construct GDY-FIN56-RAP (GFR) polymer self-assembled nanoplatforms against GBM. GDY could effectively load FIN56 and FIN56 released from GFR in a pH-dependent manner. The GFR nanoplatforms possessed the advantages of penetrating the BBB and acidic environment-induced in situ FIN56 release. Moreover, GFR nanoplatforms induced GBM cell ferroptosis by inhibiting GPX4 expression, and 808 nm irradiation reinforced GFR-mediated ferroptosis by elevating the temperature and promoting FIN56 release from GFR. In addition, the GFR nanoplatforms were inclined to locate in tumor tissue, inhibit GBM growth, and prolong lifespan by inducing GPX4-mediated ferroptosis in an orthotopic xenograft mouse model of GBM; meanwhile, 808 nm irradiation further improved these GFR-mediated effects. Hence, GFR may be a potential nanomedicine for cancer therapy, and GFR combined with photothermal therapy may be a promising strategy against GBM.

Identification and Spatial Visualization of Dysregulated Bile Acid Metabolism in High-Fat Diet-Fed Mice by Mass Spectral Imaging.

Changes in overall bile acid (BA) levels and specific BA metabolites are involved in metabolic diseases, gastrointestinal, and liver cancer. BAs have become established as important signaling molecules that enable fine-tuned inter-tissue communication within the enterohepatic circulation. The liver, BAs site of production, displayed physiological and functional zonal differences in the periportal zone versus the centrilobular zone. In addition, BA metabolism shows regional differences in the intestinal tract. However, there is no available method to detect the spatial distribution and molecular profiling of BAs within the enterohepatic circulation. Herein, we demonstrated the application in mass spectrometry imaging (MSI) with a high spatial resolution (3 µm) plus mass accuracy matrix-assisted laser desorption ionization (MALDI) to imaging BAs and N-1-naphthylphthalamic acid (NPA). Our results could clearly determine the zonation patterns and regional difference characteristics of BAs on mouse liver, ileum, and colon tissue sections, and the relative content of BAs based on NPA could also be ascertained. In conclusion, our method promoted the accessibility of spatial localization and quantitative study of BAs on gastrointestinal tissue sections and demonstrated that MALDI-MSI was a valuable tool to investigate and locate several BA molecules in different tissue types leading to a better understanding of the role of BAs behind the gastrointestinal diseases.

Estrogen profile- and pharmacogenetics-based lamotrigine dosing regimen optimization: Recommendations for pregnant women with epilepsy.

During pregnancy, various physiological changes occur that can alter the pharmacokinetics of antiepileptic drugs, such as lamotrigine (LTG). Anticipating the change in LTG dose required to achieve a pre-pregnancy target concentration is challenging. This study aimed to develop a refined population pharmacokinetic (PopPK) model of LTG in pregnant women with epilepsy (WWE) to identify factors explaining the variability in pharmacokinetics and to establish a model-informed individualized dosing regimen. On that basis, a coarsened model containing only clinical variables was also developed to examine its predictive performance compared to the refined model. In total, 322 concentration-time points from 51 pregnant WWE treated with LTG were employed to establish a refined PopPK model that included endogenous estrogen profiles, variants of candidate genes encoding LTG-metabolizing enzymes and -transporter proteins, and other clinical variables and a coarsened model that included only clinical variables, respectively. Data from an additional 11 patients were used for external validation of these two models. A nonlinear mixed-effect modeling approach was used for PopPK analysis of LTG. The standard goodness-of-fit method, bootstrap, normalized prediction distribution errors and external evaluation were adopted to estimate the stability and predictive performance of the candidate models. Akaike information criterion (AIC) was used to compare the goodness of fit between these two models. A lower AIC indicates a better fit of the data and the preferred model. Recommended dosing regimens for pregnant WWE were selected using Monte Carlo simulation based on the established optimal model. In the refined PopPK model, the population mean of apparent LTG clearance (CL/F) in pregnant WWE was estimated to be 2.82 L/h, with an inter-individual variability of 23.6%. PopPK analysis indicated that changes in estrogen profile during pregnancy were the predominant reason for the significant variations in LTG-CL/F. Up to the 3rd trimester, the concentration accumulation effect of E2 increased LTG-CL/F by 5.109 L/h from baseline levels. Contrary to effect of E2, E3 as the main circulating estrogen in pregnancy with a peak value of 34.41 ng/mL is 1000-fold higher than that in non-pregnancy reduced LTG-CL/F by 1.413 L/h. In addition, the UGT2B7 rs4356975 C > T and ABCB1 rs1128503 A > G variants may contribute to a better understanding of the inter-individual variability in LTG-CL/F. LTG-CL/F was 1.66-fold higher in UGT2B7 rs4356975 CT or TT genotype carriers than in CC genotype carriers. In contrast, ABCB1 rs1128503 GG genotype carriers had only 71.9% of the LTG-CL/F of AA or AG genotype carriers. In the coarsened PopPK model, the gestational age was a promising predictor of changes in LTG-CL/F. When comparing these two models, the refined PopPK model was favored over the coarsened PopPK model (AIC = -30.899 vs. -20.017). Monte Carlo simulation based on optimal PopPK model revealed that the LTG dosage administered to carriers of the UGT2B7 rs4356975 CT or TT genotype required a 33-50% increase to reach the pre-pregnancy target concentration, and carriers of the ABCB1 rs1128503 GG genotype required a 33-66% lower dose of LTG than carriers of the ABCB1 rs1128503 AA or AG genotype. Changes in estrogen profile during pregnancy was a better predictor of variations in LTG-CL/F than gestational age. The developed model based on estrogen profile and pharmacogenetics can serve as a foundation for further optimization of dosing regimens of LTG in pregnant WWE.

Vitamin D deficiency exacerbates Alzheimer-like pathologies by reducing antioxidant capacity.

Vitamin D (VD) deficiency is prevalent among aging people and Alzheimer's disease (AD) patients. However, the roles of VD deficiency in the pathology of AD remain largely unexplored. In this study, APP/PS1 mice were fed a VD-deficient diet for 13 weeks to evaluate the effects of VD deficiency on the learning and memory functions and the neuropathological characteristics of the mice. Our study revealed that VD deficiency accelerated cognitive impairment in the APP/PS1 mice. Mechanistic studies revealed that VD deficiency promoted glial activation and increased inflammatory factor secretion. Furthermore, VD deficiency increased the production and deposition of Aß by elevating the expression levels of amyloid precursor protein (APP) and ß-site APP cleavage enzyme 1 (BACE1). In addition, VD deficiency increased the phosphorylation of Tau at Thr181, Thr205 and Ser396 by increasing the activities of cyclin-dependent kinase 5 (CDK5) and glycogen synthase kinase 3α/ß (GSK3α/ß) and promoted synaptic dystrophy and neuronal loss. All these effects of VD deficiency may be ascribed to enhanced oxidative stress via the downregulation of superoxide dismutase 1 (SOD1), glutathione peroxidase 4 (GPx4) and cystine/glutamate exchanger (xCT). Taken together, our data suggest that VD deficiency exacerbates Alzheimer-like pathologies via promoting inflammatory stress, increasing Aß production and elevating Tau phosphorylation by decreasing antioxidant capacity in the brains of APP/PS1 mice. Hence, rescuing the VD status of AD patients should be taken into consideration during the treatment of AD.

Cynomolgus Monkeys With Spontaneous Type-2-Diabetes-Mellitus-Like Pathology Develop Alpha-Synuclein Alterations Reminiscent of Prodromal Parkinson's Disease and Related Diseases.

Available evidence suggests that diabetes mellitus (DM) is a non-genetic risk factor for Parkinson's disease (PD). PD and DM have shared similarities in pathogenetic mechanisms, including age, environmental factors, inflammatory reaction, and protein aggregation, etc. α-Synuclein is the primary protein component in the protein inclusions in PD, while islet amyloid polypeptide (IAPP) aggregates to form amyloid structures in ß cells in type 2 diabetes mellitus (T2DM). Pancreatic and cerebral functions, pancreas and brain α-synuclein deposition as well as striatal alterations, were assessed in spontaneously developed T2DM monkeys and age-matched normal monkeys. We demonstrated increased accumulation, aggregation, and phosphorylation of α-synuclein, and IAPP in the pancreatic islets of spontaneously developed T2DM monkeys, compared to the age-matched normal subjects. Double immunofluorescence analyses showed complete overlap between α-synuclein and IAPP in the pancreatic islets. In addition, in T2DM monkeys' brain, we observed concomitantly increased accumulation and phosphorylation of α-synuclein in the cortex, pre-commissural putamen and dopaminergic neurons in the substantia nigra, which interestingly showed high correlation with levels of fasting plasma glucose (FPG), triglyceride (TG), and high density lipoprotein (HDL). Our data indicates the close association between IAPP and α-synuclein and the potential link between T2DM and PD, which implies that T2DM may facilitate PD disease onset and progress by interfering with the pathological protein aggregation both in the pancreatic islets and the brain.

Dl-3-n-Butylphthalide Inhibits NLRP3 Inflammasome and Mitigates Alzheimer's-Like Pathology via Nrf2-TXNIP-TrX Axis.

AIMS: Oxidative stress and neuroinflammation play important roles in the pathology of Alzheimer's disease (AD). Thioredoxin-interacting protein (TXNIP), an endogenous inhibitor of antioxidant thioredoxin, is suspected to be an important modulator of oxidative stress and inflammation. However, the underlying mechanism involved in the abnormal homeostasis of TXNIP-thioredoxin (TrX) in AD pathogenesis remains unclear. RESULTS: Using the Swedish mutant form of APP (APPswe)/PSEN1dE9 transgenic mouse (APP/PS1) and human-derived neuronal cells as model systems, we disclosed the impairment of the nuclear factor erythroid 2-related factor 2 (Nrf2)-TXNIP-TrX signaling in Alzheimer's-like pathology. We observed that the immune staining of TXNIP was increased in postmortem AD brain. The chronic accumulation of inflammatory mediator in neuronal cells facilitates interactions of TXNIP-nucleotide binding oligomerization domain-like receptor family, pyrin domain containing 3 (NLRP3) and NLRP3-ASC, which increases ß-amyloid (Aß) secretion. The antioxidant Dl-3-n-butylphthalide (Dl-NBP) is commonly used for cerebral ischemia treatment. In our study, we elucidated for new mechanisms by which Dl-NBP enhanced TrX activity, suppressed TXNIP, and ameliorated neuronal apoptosis in the APP/PS1 mouse brains. In human glioblastoma A172 cells and neuroblastoma SH-SY5Y cells, we delineated the Dl-NBP-mediated signaling pathways by which Dl-NBP-dependent upregulation of Nrf2 mediated the reciprocal regulation of reducing proinflammatory cytokine and inhibiting Aß production in the glial and neuronal cells overexpressing APPswe. INNOVATION: Our data provide a novel insight into the molecular mechanism that impairments of Nrf2-TXNIP-TrX system may be involved in the imbalance of cellular redox homeostasis and inflammatory damage in the AD brain. CONCLUSION: Dl-NBP treatment could suppress TXNIP-NLRP3 interaction and inhibit NLRP3 inflammasome activation via upregulating Nrf2. These findings may provide an instrumental therapeutic approach for AD. Antioxid. Redox Signal. 00, 000-000.

Zinc Chelator Inhibits Zinc-Induced Islet Amyloid Polypeptide Deposition and Apoptosis in INS-1 Cells.

Amyloid deposition and beta cell apoptosis are characteristic pathological features of type 2 diabetes mellitus (DM). Islet amyloid polypeptide (IAPP) is the most abundant component of amyloid deposition. Monomeric IAPP does not form amyloid deposition, but the fibrous IAPP may aggregate and form amyloid deposits. Previous studies have shown that zinc is closely related to IAPP deposition through crosslink with monomeric IAPP into fibrous aggregates. In this study, we aimed to investigate whether chelating zinc could inhibit zinc-induced amyloid deposits and apoptosis of islet beta cell. N, N, N', N'-Tetrakis (2-pyridylmethyl) ethylenediamine (TPEN) is a specific chelator of zinc, with membrane permeability. It could effectively reduce the concentration of intracellular zinc. So, we used TPEN to treat hIAPP-transfected INS-1 cells. By MTT assay, the concentration (1 µM) and incubation time (12 h) of TPEN without affecting cell viability were determined. The results showed that TPEN reduced zinc-induced IAPP deposition in the culture system. Furthermore, we analyzed the effect of zinc and TPEN on the apoptosis and insulin level. The results showed that TPEN could reverse zinc-induced INS-1 cell apoptosis and insulin secretion. And the anti-apoptosis effects of TPEN is related to extracellular regulated protein kinases (ERK)/c-jun N-terminal kinase (JNK) signaling pathway. The present data indicated that chelating zinc could inhibit zinc-induced amyloid deposition and beta cell apoptosis. Thus, maintaining zinc homeostasis in islet beta cell might become a useful strategy for DM therapy.

Iron and Alzheimer's Disease: From Pathogenesis to Therapeutic Implications.

As people age, iron deposits in different areas of the brain may impair normal cognitive function and behavior. Abnormal iron metabolism generates hydroxyl radicals through the Fenton reaction, triggers oxidative stress reactions, damages cell lipids, protein and DNA structure and function, and ultimately leads to cell death. There is an imbalance in iron homeostasis in Alzheimer's disease (AD). Excessive iron contributes to the deposition of ß-amyloid and the formation of neurofibrillary tangles, which in turn, promotes the development of AD. Therefore, iron-targeted therapeutic strategies have become a new direction. Iron chelators, such as desferoxamine, deferiprone, deferasirox, and clioquinol, have received a great deal of attention and have obtained good results in scientific experiments and some clinical trials. Given the limitations and side effects of the long-term application of traditional iron chelators, alpha-lipoic acid and lactoferrin, as self-synthesized naturally small molecules, have shown very intriguing biological activities in blocking Aß-aggregation, tauopathy and neuronal damage. Despite a lack of evidence for any clinical benefits, the conjecture that therapeutic chelation, with a special focus on iron ions, is a valuable approach for treating AD remains widespread.

A novel role for zinc transporter 8 in the facilitation of zinc accumulation and regulation of testosterone synthesis in Leydig cells of human and mouse testicles.

OBJECTIVE: Zinc is intimately involved in testosterone production. Zinc transporter 8 (ZnT8) is found to be localized in insulin secretory granules as a ß-cell specific Zn transporter. The effect of ZnT8 and related zinc accumulation in steroidogenesis, however, is still unknown. The present study aimed to explore whether ZnT8 plays a role in the facilitation of zinc accumulation and regulation of testosterone synthesis in testicles. METHODS: Leydig cells were isolated from the testicles of human, CD-1 suckling and ZnT8-KO mice. Zn accumulation in mitochondria was induced by hCG stimulation. Transfection of hZnT8-EGFP and RNA interfere of mZnT8 were done in MLTC-1 cells. ZnT8 expression and its co-localization with steroidogenic acute regulatory (StAR) protein were analyzed with RT-PCR, Western blot and dual-fluorescent staining protocols. Serum testosterone levels in mice were determined with chemiluminescent enzyme immunoassay. RESULTS: ZnT8 was found to be presented in Leydig cells and up-regulated in suckling mouse Leydig cells and MLTC-1 cells after hCG administration, by which zinc accumulation occurred in mitochondria. ZnT8 gene silencing or knockout inhibited stimulated progesterone and testosterone production, reduced stimulated zinc accumulation and down-regulated phosphorylated steroidogenic acute regulatory (StAR) expression in Leydig cells. Furthermore, an inhibitor (H89) of PKA blocked hCG-stimulated progesterone caused by ZnT8 over-expression and zinc treatment. CONCLUSION: The present study provided the first evidence that ZnT8 transports Zn into Leydig cell mitochondria with gonadotropin stimulation and suggests that ZnT8 may play a role in testosterone production via the PKA signaling pathway.

Lower Expression of Ndfip1 Is Associated With Alzheimer Disease Pathogenesis Through Decreasing DMT1 Degradation and Increasing Iron Influx.

We have previously reported that high expression of divalent metal transporter 1 (DMT1) plays a crucial role in iron dyshomeostasis and ß-amyloid (Aß) peptide generation in the brain of Alzheimer's disease (AD). Recent studies have shown that Nedd4 family interacting protein 1 (Ndfip1) can degrade DMT1 through ubiquitination pathway and reduce the accumulation of intracellular iron. The present study aims to evaluate whether Ndfip1 is involved in AD pathogenesis through mediating DMT1 degradation and iron metabolism. ß-amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mouse and Ndfip1 transfected SH-SY5Y cells were used in this study. Immunohistochemistry and Western blot were performed to examine the distribution and expression levels of Ndfip1 and DMT1. In addition, ELISA and calcein fluorescence were carried out for analyzing the levels of Aß peptide and iron influx, respectively. The results showed that Ndfip1 immunoreactivity was decreased in the cortex and hippocampus of APP/PS1 mice, compared with wild type (WT) controls. Colocalization of Ndfip1 and Aß within senile plaques could be observed. Immunoblot analyses showed that low expression of Ndfip1 and high expression of DMT1 proteins were detected in APP/PS1 mouse brain, compared with age-matched WT animals. Overexpression of Ndfip1 down-regulated DMT1 expression, and reduced iron influx and Aß secretion in SH-SY5Y cells. Further, overexpressed Ndfip1 significantly attenuated iron-induced cell damage in Ndfip1 transfected cells. The present study suggests that lower expression of Ndfip1 might be associated with the pathogenesis of AD, through decreasing DMT1 degradation and increasing iron accumulation in the brain.

Magnesium Ions Inhibit the Expression of Tumor Necrosis Factor α and the Activity of γ-Secretase in a ß-Amyloid Protein-Dependent Mechanism in APP/PS1 Transgenic Mice.

Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognitive impairment. The neuropathological features of AD are the aggregation of extracellular amyloid ß-protein (Aß) and tau phosphorylation. Recently, AD was found to be associated with magnesium ion (Mg2+) deficit and tumor necrosis factor-alpha (TNF-α) elevation in the serum or brains of AD patients. To study the relationship between Mg2+ and TNF-α, we used human- or mouse-derived glial and neuronal cell lines or APP/PS1 transgenic (Tg) mice as in vitro and in vivo experimental models, respectively. Our data demonstrates that magnesium-L-threonate (MgT) can decrease the expression of TNF-α by restoring the levels of Mg2+ in glial cells. In addition, PI3-K/AKT and NF-κB signals play critical roles in mediating the effects of Mg2+ on suppressing the expression of TNF-α. In neurons, Mg2+ elevation showed similar suppressive effects on the expression of presenilin enhancer 2 (PEN2) and nicastrin (NCT) through a PI3-K/AKT and NF-κB-dependent mechanism. As the major components of γ-secretase, overexpression of presenilin 1 (PS1), PEN2 and NCT potentially promote the synthesis of Aß, which in turn activates TNF-α in glial cells. Reciprocally, TNF-α stimulates the expression of PEN2 and NCT in neurons. The crosstalk between TNF-α and Aß in glial cells and neurons could ultimately aggravate the development and progression of AD.

HDAC1 Governs Iron Homeostasis Independent of Histone Deacetylation in Iron-Overload Murine Models.

AIMS: Iron-overload disorders are common and could lead to significant morbidity and mortality worldwide. Due to limited treatment options, there is a great need to develop novel strategies to remove the excess body iron. To discover potential epigenetic modulator in hepcidin upregulation and subsequently decreasing iron burden, we performed an epigenetic screen. The in vivo effects of the identified compounds were further tested in iron-overload mouse models, including Hfe-/-, Hjv-/-, and hepatocyte-specific Smad4 knockout (Smad4fl/fl;Alb-Cre+) mice. RESULTS: Entinostat (MS-275), the clinical used histone deacetylase 1 (HDAC1) inhibitor, was identified the most potent hepcidin agonist. Consistently, Hdac1-deficient mice also presented higher hepcidin levels than wild-type controls. Notably, the long-term treatment with entinostat in Hfe-/- mice significantly alleviated iron overload through upregulating hepcidin transcription. In contrast, entinostat showed no effect on hepcidin expression and iron levels in Smad4fl/fl;Alb-Cre+ mice. Further mechanistic studies revealed that HDAC1 suppressed expression of hepcidin through interacting with SMAD4 rather than deacetylation of SMAD4 or histone-H3 on the hepcidin promoter. INNOVATION: The findings uncovered HDAC1 as a novel hepcidin suppressor through complexing with SMAD4 but not deacetylation of either histone 3 or SMAD4. In addition, our study suggested a novel implication of entinostat in treating iron-overload disorders. CONCLUSIONS: Based on our results, we conclude that entinostat strongly activated hepcidin in vivo and in vitro. HDAC1 could serve as a novel hepcidin suppressor by binding to SMAD4, effect of which is independent of BMP/SMAD1/5/8 signaling. Antioxid. Redox Signal. 28, 1224-1237.

COX-2 metabolic products, the prostaglandin I2 and F2α, mediate the effects of TNF-α and Zn2+ in stimulating the phosphorylation of Tau.

Although the roles of cyclooxygenase-2 (COX-2) and prostaglandins (PGs) in regulating amyloid precursor protein (APP) cleavage and ß-amyloid protein (Aß) production have been the subjects of numerous investigations, their effects on tau phosphorylation have been largely overlooked. Using human TauP301S transgenic (Tg) mice as in vivo model, our results demonstrated that PGI2 and PGF2α mediated the effects of tumor necrosis factor α (TNF-α) and Zinc ions (Zn2+) on upregulating the phosphorylation of tau via the PI3-K/AKT, ERK1/2 and JNK/c-Jun signaling pathways. Specifically, we initially found that high level of Zn2+ upregulates the expression of COX-2 via stimulating the activity of TNF-α in a zinc transporter 3 (ZnT3)-dependent mechanism. COX-2 upregulation then stimulates the phosphorylation of tau at both Ser 202 and Ser 400/Thr 403/Ser 404 via PGI2 and F2α treatment either in i.c.v.-injected mice or in n2a cells. Using n2a cells as in vitro model, we further revealed critical roles for the PI3-K/AKT, ERK1/2 and JNK/c-Jun pathways in mediating the effects of PGI2 and F2α in the phosphorylation of tau. Finally, NS398 treatment delayed the onset of cognitive decline in TauP301S Tg mice according to the nest construction or limb clasping test.

Serum Copper, Zinc, and Iron Levels in Patients with Alzheimer's Disease: A Meta-Analysis of Case-Control Studies.

Background: Many publications have investigated the association between metal ions and the risk of Alzheimer's disease (AD), but the results were ambiguous. Aims: The objective of this study was to assess the association between the serum levels of metals (copper/zinc/iron) and the risk of AD via meta-analysis of case-control studies. Methods: We screened literatures published after 1978 in the Pubmed, Embase, Cochrane library, Web of Science and ClinicalTrials.gov. Electronic databases. By using Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, we performed a systematic review of the 407 publications, there are 44 of these publications met all inclusion criteria. The Review Manager 5.3 software was used to calculate available data from each study. Results: Consistent with the conclusions of other meta-analysis, our results demonstrated serum copper levels were significantly higher [MD = 9.27, 95% CI (5.02-13.52); p < 0.0001], and the serum zinc levels were significantly lower in AD patients than in healthy controls [MD = -6.12, 95% CI (-9.55, -2.69); p = 0.0005]. Serum iron levels were significantly lower in AD patients than in healthy controls after excluded two studies [MD = -13.01, 95% CI (-20.75, -5.27); p = 0.001]. Conclusion: The results of our meta-analysis provided rigorous statistical support for the association of the serum levels of metals and the risk of AD, suggesting a positive relationship between the serum copper levels and AD risk, and a negative relationship between the serum zinc/iron levels and AD risk.

New Iridoids from Scrophularia ningpoensis.

Five new compounds including five iridoids (1-5) and six known compounds were isolated from the rhizomes of Scrophularia ningpoensis. Their structures were determined by extensive NMR and IR, MS spectroscopic data analyses. The anti-inflammatory, antibacterial, antifungal, and cytotoxic activities of the isolated compounds were evaluated. Compound 11 exhibited significant inhibitory effects on lipopolysaccharide-induced nitric oxide production in RAW264.7 macrophage cells.

Erythrocyte membrane-encapsulated celecoxib improves the cognitive decline of Alzheimer's disease by concurrently inducing neurogenesis and reducing apoptosis in APP/PS1 transgenic mice.

Alzheimer's disease (AD) is characterized by the loss of neurogenesis and excessive induction of apoptosis. The induction of neurogenesis and inhibition of apoptosis may be a promising therapeutic approach to combating the disease. Celecoxib (CB), a cyclooxygenase-2 specific inhibitor, could offer neuroprotection. Specifically, the CB-encapsulated erythrocyte membranes (CB-RBCMs) sustained the release of CB over a period of 72 h in vitro and exhibited high brain biodistribution efficiency following intranasal administration, which resulted in the clearance of aggregated ß-amyloid proteins (Aß) in neurons. The high accumulation of the CB-RBCMs in neurons resulted in a decrease in the neurotoxicity of CB and an increase in the migratory activity of neurons, and alleviated cognitive decline in APP/PS1 transgenic (Tg) mice. Indeed, COX-2 metabolic products including prostaglandin E2 (PGE2) and PGD2, PGE2 induced neurogenesis by enhancing the expression of SOD2 and 14-3-3ζ, and PGD2 stimulated apoptosis by increasing the expression of BIK and decreasing the expression of ARRB1. To this end, the CB-RBCMs achieved better effects on concurrently increasing neurogenesis and decreasing apoptosis than the phospholipid membrane-encapsulated CB liposomes (CB-PSPD-LPs), which are critical for the development and progression of AD. Therefore, CB-RBCMs provide a rational design to treat AD by promoting the self-repairing capacity of the brain.

Intranasal Lactoferrin Enhances α-Secretase-Dependent Amyloid Precursor Protein Processing via the ERK1/2-CREB and HIF-1α Pathways in an Alzheimer's Disease Mouse Model.

Growing evidence suggests that lactoferrin (Lf), an iron-binding glycoprotein, is a pleiotropic functional nutrient. In addition, Lf was recently implicated as a neuroprotective agent. These properties make Lf a valuable therapeutic candidate for the treatment of Alzheimer's disease (AD). However, the mechanisms regulating the physiological roles of Lf in the pathologic condition of AD remain unknown. In the present study, an APPswe/PS1DE9 transgenic mouse model of AD was used. We explored whether intranasal human Lf (hLf) administration could reduce ß-amyloid (Aß) deposition and ameliorate cognitive decline in this AD model. We found that hLf promoted the non-amyloidogenic metabolism of amyloid precursor protein (APP) processing through activation of α-secretase a-disintegrin and metalloprotease10 (ADAM10), resulting in enhanced cleavage of the α-COOH-terminal fragment of APP and the corresponding elevation of the NH2-terminal APP product, soluble APP-α (sAPPα), which consequently reduced Aß generation and improved spatial cognitive learning ability in AD mice. To gain insight into the molecular mechanism by which Lf modulates APP processing, we evaluated the involvement of the critical molecules for APP cleavage and the signaling pathways in N2a cells stably transfected with Swedish mutant human APP (APPsw N2a cells). The results show that the ERK1/2-CREB and HIF-1α signaling pathways were activated by hLf treatment, which is responsible for the expression of induced ADAM10. Additional tests were performed before suggesting the potential use of hLf as an antioxidant and anti-inflammatory. These findings provide new insights into the sources and mechanisms by which hLf inhibits the cognitive decline that occurs in AD via activation of ADAM10 expression in an ERK1/2-CREB and HIF-1α-dependent manner.

Magnesium ion influx reduces neuroinflammation in Aß precursor protein/Presenilin 1 transgenic mice by suppressing the expression of interleukin-1ß.

Alzheimer's disease (AD) has been associated with magnesium ion (Mg2+) deficits and interleukin-1ß (IL-1ß) elevations in the serum or brains of AD patients. However, the mechanisms regulating IL-1ß expression during Mg2+ dyshomeostasis in AD remain unknown. We herein studied the mechanism of IL-1ß reduction using a recently developed compound, magnesium-L-threonate (MgT). Using human glioblastoma A172 and mouse brain D1A glial cells as an in vitro model system, we delineated the signaling pathways by which MgT suppressed the expression of IL-1ß in glial cells. In detail, we found that MgT incubation stimulated the activity of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) and peroxisome proliferator-activated receptor gamma (PPARγ) signaling pathways by phosphorylation, which resulted in IL-1ß suppression. Simultaneous inhibition of the phosphorylation of ERK1/2 and PPARγ induced IL-1ß upregulation in MgT-stimulated glial cells. In accordance with our in vitro data, the intracerebroventricular (i.c.v) injection of MgT into the ventricles of APP/PS1 transgenic mice and treatment of Aß precursor protein (APP)/PS1 brain slices suppressed the mRNA and protein expression of IL-1ß. These in vivo observations were further supported by the oral administration of MgT for 5 months. Importantly, Mg2+ influx into the ventricles of the mice blocked the effects of IL-1ß or amyloid ß-protein oligomers in the cerebrospinal fluid. This reduced the stimulation of IL-1ß expression in the cerebral cortex of APP/PS1 transgenic mice, which potentially contributed to the inhibition of neuroinflammation.