AßPP-tau-HAS1 axis trigger HAS1-related nuclear speckles and gene transcription in Alzheimer's disease.

As the backbone of the extracellular matrix (ECM) and the perineuronal nets (PNNs), hyaluronic acid (HA) provides binding sites for proteoglycans and other ECM components. Although the pivotal of HA has been recognized in Alzheimer's disease (AD), few studies have addressed the relationship between AD pathology and HA synthases (HASs). Here, HASs in different regions of AD brains were screened in transcriptomic database and validated in AßPP/PS1 mice. We found that HAS1 was distributed along the axon and nucleus. Its transcripts were reduced in AD patients and AßPP/PS1 mice. Phosphorylated tau (p-tau) mediates AßPP-induced cytosolic-nuclear translocation of HAS1, and negatively regulated the stability, monoubiquitination, and oligomerization of HAS1, thus reduced the synthesis and release of HA. Furthermore, non-ubiquitinated HAS1 mutant lost its enzyme activity, and translocated from the cytosol into the nucleus, forming nuclear speckles (NS). Unlike the splicing-related NS, less than 1 % of the non-ubiquitinated HAS1 co-localized with SRRM2, proving the regulatory role of HAS1 in gene transcription, indirectly. Thus, differentially expressed genes (DEGs) related to both non-ubiquitinated HAS1 mutant and AD were screened using transcriptomic datasets. Thirty-nine DEGs were identified, with 64.1 % (25/39) showing consistent results in both datasets. Together, we unearthed an important function of the AßPP-p-tau-HAS1 axis in microenvironment remodeling and gene transcription during AD progression, involving the ubiquitin-proteasome, lysosome, and NS systems.

Secreted endogenous macrosomes reduce Aß burden and ameliorate Alzheimer's disease.

Innovative therapeutic strategies are urgently needed for Alzheimer's disease (AD) due to the increasing size of the aging population and the lack of effective drug treatment. Here, we report the therapeutic effects of extracellular vesicles (EVs) secreted by microglia, including macrosomes and small EVs, on AD-associated pathology. Macrosomes strongly inhibited ß-amyloid (Aß) aggregation and rescued cells from Aß misfolding-induced cytotoxicity. Furthermore, macrosome administration reduced Aß plaques and ameliorated cognitive impairment in mice with AD. In contrast, small EVs slightly promoted Aß aggregation and did not improve AD pathology. Proteomic analysis of small EVs and macrosomes revealed that macrosomes harbor several important neuroprotective proteins that inhibit Aß misfolding. In particular, the small integral membrane protein 10-like protein 2B in macrosomes has been shown to inhibit Aß aggregation. Our observations provide an alternative therapeutic strategy for the treatment of AD over conventional ineffective drug treatments.

Dopamine-independent development and maintenance of mouse striatal medium spiny neuron dendritic spines.

Striatal medium spiny neurons (MSNs) and striatal dopamine (DA) innervation are profoundly important for brain function such as motor control and cognition. A widely accepted theory posits that striatal DA loss causes (or leads to) MSN dendritic atrophy. However, examination of the literature indicates that the data from Parkinson's disease (PD) patients and animal PD models were contradictory among studies and hard to interpret. Here we have re-examined the potential effects of DA activity on MSN morphology or lack thereof. We found that in 15-day, 4- and 12-month old Pitx3 null mutant mice that have severe DA denervation in the dorsal striatum while having substantial residual DA innervation in the ventral striatum, MSN dendrites and spine numbers were similar in dorsal and ventral striatum, and also similar to those in normal mice. In 15-day, 4- and 12-month old tyrosine hydroxylase knockout mice that cannot synthesize L-dopa and thus have no endogenous DA in the entire brain, MSN dendrites and spine numbers were also indistinguishable from age-matched wild-type (WT) mice. Furthermore, in adult WT mice, unilateral 6-OHDA lesion at 12 months of age caused an almost complete striatal DA denervation in the lesioned side, but MSN dendrites and spine numbers were similar in the lesioned and control sides. Taken together, our data indicate that in mice, the development and maintenance of MSN dendrites and spines are DA-independent such that DA depletion does not trigger MSN dendritic atrophy; our data also suggest that the reported MSN dendritic atrophy in PD may be a component of neurodegeneration in PD rather than a consequence of DA denervation.

The human islet amyloid polypeptide reduces hippocampal tauopathy and behavioral impairments in P301S mice without inducing neurotoxicity or seeding amyloid aggregation.

Recent evidence suggests that human islet amyloid polypeptide (h-IAPP) accumulates in the brains of Alzheimer's disease (AD) patients and may interact with Aß or microtubule associated protein tau to associate with the neurodegenerative process. Increasing evidence indicates a potential protective effect of h-IAPP against Aß-induced neurotoxicity in AD mouse models. However, a direct therapeutic effect of h-IAPP supplementation on tauopathy has not been established. Here, we found that long-term h-IAPP treatment attenuated tau hyperphosphorylation levels and induced neuroinflammation and oxidative damage, prevented synaptic loss and neuronal degeneration in the hippocampus, and alleviated behavioral deficits in P301S transgenic mice (a mouse model of tauopathy). Restoration of insulin sensitization, glucose/energy metabolism, and activated BDNF signaling also contributed to the underlying mechanisms. These findings suggest that seemly h-IAPP has promise for the treatment of neurodegenerative disorders with tauopathy, such as AD.

Novel melatonin-trientine conjugate as potential therapeutic agents for Alzheimer's disease.

Researchers continue to explore drug targets to treat the characteristic pathologies of Alzheimer's disease (AD). Some drugs relieve the pathological processes of AD to some extent, but the failed clinical trials indicate that multifunctional agents seem more likely to achieve the therapy goals for this neurodegenerative disease. Herein, a novel compound named melatonin-trientine (TM) has been covalently synthesized with the natural antioxidant compounds melatonin and the metal ion chelator trientine. After toxicological and pharmacokinetic verification, we elucidated the effects of intraperitoneal administration of TM on AD-like pathology in 6-month-old mice that express both the ß-amyloid (Aß) precursor protein and presenilin-1 (APP/PS1). We found that TM significantly decreased Aß deposition and neuronal degeneration in the brains of the APP/PS1 double transgenic mice. This result may be due to the upregulation of iron regulatory protein-2 (IRP2), insulin degrading enzyme (IDE), and low density lipoprotein receptor related protein 1 (LRP1), which leads to decreases in APP and Aß levels. Additionally, TM may promote APP non-amyloidogenic processing by activating the melatonin receptor-2 (MT2)-dependent signaling pathways, but not MT1. In addition, TM plays an important role in blocking γ-secretase, tau hyperphosphorylation, neuroinflammation, oxidative stress, and metal ion dyshomeostasis. Our results suggest that TM may effectively maximize the therapeutic efficacy of targeting multiple mechanisms associated with AD pathology.

ATP13A2 Declines Zinc-Induced Accumulation of α-Synuclein in a Parkinson's Disease Model.

Parkinson's disease (PD) is characterized by the presence of Lewy bodies caused by α-synuclein. The imbalance of zinc homeostasis is a major cause of PD, promoting α-synuclein accumulation. ATP13A2, a transporter found in acidic vesicles, plays an important role in Zn2+ homeostasis and is highly expressed in Lewy bodies in PD-surviving neurons. ATP13A2 is involved in the transport of zinc ions in lysosomes and exosomes and inhibits the aggregation of α-synuclein. However, the potential mechanism underlying the regulation of zinc homeostasis and α-synuclein accumulation by ATP13A2 remains unexplored. We used α-synuclein-GFP transgenic mice and HEK293 α-synuclein-DsRed cell line as models. The spatial exploration behavior of mice was significantly reduced, and phosphorylation levels of α-synuclein increased upon high Zn2+ treatment. High Zn2+ also inhibited the autophagy pathway by reducing LAMP2a levels and changing the expression of LC3 and P62, by reducing mitochondrial membrane potential and increasing the expression of cytochrom C, and by activating the ERK/P38 apoptosis signaling pathway, ultimately leading to increased caspase 3 levels. These protein changes were reversed after ATP13A2 overexpression, whereas ATP13A2 knockout exacerbated α-synuclein phosphorylation levels. These results suggest that ATP13A2 may have a protective effect on Zn2+-induced abnormal aggregation of α-synuclein, lysosomal dysfunction, and apoptosis.

Aspartic Acid-Modified Phospholipids Regulate Cell Response and Rescue Memory Deficits in APP/PS1 Transgenic Mice.

Misfolding and accumulation of amyloid-ß (Aß) to form senile plaques are the main neuropathological signatures of Alzheimer's disease (AD). Decreasing Aß production, inhibiting Aß aggregation, and clearing Aß plaques are thus considered an important strategy for AD treatment. However, numerous drugs cannot enter the AD clinical trials due to unsatisfactory biocompatibility, poor blood-brain barrier penetration, little biomarker impact, and/or low therapeutic indicators. Here, a pair of chiral aspartic acid-modified 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (l- and d-Asp-DPPE) are prepared to build stabilized chiral liposomes. We find that both l- and d-liposomes are able to rescue Aß aggregation-induced apoptosis, oxidative stress, and calcium homeostasis, in which the effect of d-liposomes is more obvious than that of l-ones. Furthermore, in AD model mice (APPswe/PS1d9 double-transgenic mice), chiral liposomes not only show biosafety but also strongly improve cognitive deficits and reduce Aß deposition in the brain. Our results suggest that chiral liposomes, particularly, d-liposomes, could be a potential therapeutic approach for AD treatment. This study opens new horizons by showing that liposomes will be used for drug development in addition to delivery and targeting functions.

Identification of a glycolysis-related lncRNA prognostic signature for clear cell renal cell carcinoma.

BACKGROUND: The present study investigated the independent prognostic value of glycolysis-related long noncoding (lnc)RNAs in clear cell renal cell carcinoma (ccRCC). METHODS: A coexpression analysis of glycolysis-related mRNAs-long noncoding RNAs (lncRNAs) in ccRCC from The Cancer Genome Atlas (TCGA) was carried out. Clinical samples were randomly divided into training and validation sets. Univariate Cox regression and least absolute shrinkage and selection operator (LASSO) regression analyses were performed to establish a glycolysis risk model with prognostic value for ccRCC, which was validated in the training and validation sets and in the whole cohort by Kaplan-Meier, univariate and multivariate Cox regression, and receiver operating characteristic (ROC) curve analyses. Principal component analysis (PCA) and functional annotation by gene set enrichment analysis (GSEA) were performed to evaluate the risk model. RESULTS: We identified 297 glycolysis-associated lncRNAs in ccRCC; of these, 7 were found to have prognostic value in ccRCC patients by Kaplan-Meier, univariate and multivariate Cox regression, and ROC curve analyses. The results of the GSEA suggested a close association between the 7-lncRNA signature and glycolysis-related biological processes and pathways. CONCLUSION: The seven identified glycolysis-related lncRNAs constitute an lncRNA signature with prognostic value for ccRCC and provide potential therapeutic targets for the treatment of ccRCC patients.

A Novel Cu(II)-Binding Peptide Identified by Phage Display Inhibits Cu2+-Mediated Aß Aggregation.

Copper (Cu) has been implicated in the progression of Alzheimer's disease (AD), and aggregation of Cu and amyloid ß peptide (Aß) are considered key pathological features of AD. Metal chelators are considered to be potential therapeutic agents for AD because of their capacity to reduce metal ion-induced Aß aggregation through the regulation of metal ion distribution. Here, we used phage display technology to screen, synthesize, and evaluate a novel Cu(II)-binding peptide that specifically blocked Cu-triggered Aß aggregation. The Cu(II)-binding peptide (S-A-Q-I-A-P-H, PCu) identified from the phage display heptapeptide library was used to explore the mechanism of PCu inhibition of Cu2+-mediated Aß aggregation and Aß production. In vitro experiments revealed that PCu directly inhibited Cu2+-mediated Aß aggregation and regulated copper levels to reduce biological toxicity. Furthermore, PCu reduced the production of Aß by inhibiting Cu2+-induced BACE1 expression and improving Cu(II)-mediated cell oxidative damage. Cell culture experiments further demonstrated that PCu had relatively low toxicity. This Cu(II)-binding peptide that we have identified using phage display technology provides a potential therapeutic approach to prevent or treat AD.

Nasal Delivery of D-Penicillamine Hydrogel Upregulates a Disintegrin and Metalloprotease 10 Expression via Melatonin Receptor 1 in Alzheimer's Disease Models.

Alzheimer's disease (AD) is a type of neurodegenerative disease that is associated with the accumulation of amyloid plaques. Increasing non-amyloidogenic processing and/or manipulating amyloid precursor protein signaling could reduce AD amyloid pathology and cognitive impairment. D-penicillamine (D-Pen) is a water-soluble metal chelator and can reduce the aggregation of amyloid-ß (Aß) with metals in vitro. However, the potential mechanism of D-Pen for treating neurodegenerative disorders remains unexplored. In here, a novel type of chitosan-based hydrogel to carry D-Pen was designed and the D-Pen-CS/ß-glycerophosphate hydrogel were characterized by scanning electron microscopy and HPLC. Behavior tests investigated the learning and memory levels of APP/PS1 mice treated through the D-Pen hydrogel nasal delivery. In vivo and in vitro findings showed that nasal delivery of D-Pen-CS/ß-GP hydrogel had properly chelated metal ions that reduced Aß deposition. Furthermore, D-Pen mainly regulated A disintegrin and metalloprotease 10 (ADAM10) expression via melatonin receptor 1 (MTNR1α) and the downstream PKA/ERK/CREB pathway. The present data demonstrated D-Pen significantly improved the cognitive ability of APP/PS1 mice and reduced Aß generation through activating ADAM10 and accelerating non-amyloidogenic processing. Hence, these findings indicate the potential of D-Pen as a promising agent for treating AD.

Brain Targeting and Aß Binding Bifunctional Nanoparticles Inhibit Amyloid Protein Aggregation in APP/PS1 Transgenic Mice.

Alzheimer's disease (AD) is an insidious and progressive neurodegenerative disease with few disease-modifying treatments. A variety of peptide/protein drugs have neuroprotective effects, which brings new hope for the treatment of AD. However, the application of these drugs is limited because of their low specificity and difficulty in crossing the blood-brain barrier. Herein, using the phage display technology, we identified the Aß oligomer binding peptide (KH) and the brain targeting peptide (IS). We combined these peptides to develop a bifunctional nanoparticle (IS@NP/KH) for the delivery of Aß1-42 oligomer binding peptide into the brain. Intranasal administration of IS@NP/KH significantly attenuated the cognitive and behavioral deficits and reduced the Aß deposition in the brain of an AD animal model (APPswe/PS 1d9 double-transgenic mice). Our results suggest that intranasal IS@NP/KH administration could be a novel therapeutic strategy for the treatment of AD.

Selection of a d-Enantiomeric Peptide Specifically Binding to PHF6 for Inhibiting Tau Aggregation in Transgenic Mice.

Tauopathies refer to a group of neurodegenerative disorders caused by the accumulation of insoluble hyperphosphorylated Tau protein in the brain. The inhibition and interruption of Tau aggregation are considered important strategies to ameliorate the neurodegenerative process. Previous work has shown that hexapeptide 306VQIVYK311 (PHF6) located in the repeat domain 3 of Tau protein drives Tau aggregation and itself forms a ß-sheet structure similar to those of Tau-oligomers and neurofibrillary tangles (NFTs). In this study, a mirror image phage display technology was used to screen protease-resistant and low-immunogenic d-enantiomeric peptides for their capacity to inhibit Tau aggregation. Following the preparation of d-enantiomeric PHF6 fibrils and M13 phage peptide library biopanning, 7 sets of high specificity peptides were obtained. Through ELISA and competition inhibition assays, we chose a highly specific peptide p-NH with the sequence N-I-T-M-N-S-R-R-R-R-N-H. The molecular docking results showed that p-NH interacted with PHF6 fibrils mainly through van der Waals forces and hydrogen bonding and could inhibit PHF6 aggregation in a d-configuration and concentration-dependent manner. In vitro, p-NH prohibited the formation of PHF6 fibrils and was able to enter into mouse neuroblastoma N2a cells (N2a cells) to inhibit Tau hyperphosphorylation and aggregation. Intranasal administration of p-NH reduced NFTs and improved the cognitive ability of TauP301S transgenic mice. These findings represent a straightforward methodology to find therapeutic peptides with potential applications in tauopathies.

Screening a specific Zn(ii)-binding peptide for improving the cognitive decline of Alzheimer's disease in APP/PS1 transgenic mice by inhibiting Zn2+-mediated amyloid protein aggregation and neurotoxicity.

Zn2+ has been implicated in the progression of Alzheimer's disease (AD), as amyloid-ß protein (Aß) aggregation and neurotoxicity are mediated by zinc ions. Therefore, development of metal chelators for inhibiting and regulating metal-triggered Aß aggregation has received attention as a strategy for treating AD. Here, we used an approach based on phage display to screen for a Zn(ii)-binding peptide that specifically blocks Zn-triggered Aß aggregation. A fixed Zn(ii) resin was prepared using Ni-IDA affinity resin, and the target Zn(ii) was screened by interaction with a heptapeptide phage library. After negative biopanning against IDA and four rounds of positive biopanning against Zn(ii), high specificity Zn(ii)-binding phages were obtained. Through DNA sequencing and ELISA, 15 sets of Zn(ii)-binding peptides with high histidine contents were identified. We chose a highly specific peptide against Zn(ii) with the sequence of H-M-Q-T-N-H-H, and its abilities to chelate Zn2+ and inhibit Zn2+-mediated Aß aggregation were assessed in vitro. We loaded the Zn(ii)-binding peptide onto PEG-modified chitosan nanoparticles (NPs) to improve the stability and the bioavailability of the Zn(ii) binding peptide. PEG-modified chitosan NPs loaded with Zn(ii)-binding peptide (PEG/PZn-CS NPs) reduced Zn2+ concentrations and Aß secretion in mouse neuroblastoma (N)2a cells stably over-expressing the APP Swedish mutation (N2aswe). Zn2+-Induced neurotoxicity, oxidative stress, and apoptosis were attenuated by PEG/PZn-CS NPs. Intranasal administration of PEG/PZn-CS NPs improved the cognitive ability of APPswe/PS1d9 (APP/PS1) double-transgenic mice and reduced Aß plaques in the mouse brain. This study indicated that a Zn(ii)-binding peptide and its NPs have promise as a potential anti-AD agent.

Unveil the transcriptional landscape at the Cryptococcus-host axis in mice and nonhuman primates.

Pathogens and hosts require rapid modulation of virulence and defense mechanisms at the infection axis, but monitoring such modulations is challenging. In studying the human fungal pathogen Cryptococcus neoformans, mouse and rabbit infection models are often employed to shed light on the disease mechanisms but that may not be clinically relevant. In this study, we developed an animal infection model using the non-human primate cynomolgus monkey Macaca fascicularis. In addition, we systematically profiled and compared transcriptional responses between the infected mice and the cynomolgus monkey, using simultaneous or dual RNA next-generation sequencing. We demonstrated that there are shared but distinct transcriptional profiles between the two models following C. neoformans infection. Specifically, genes involved in immune and inflammatory responses are all upregulated. Osteoclastogenesis and insulin signaling are also significantly co-regulated in both models and disrupting an osteoclastogenesis-associated gene (OC-STAMP) or the insulin-signaling process significantly altered the host tolerance to C. neoformans. Moreover, C. neoformans was shown to activate metal sequestration, dampen the sugar metabolism, and control cell morphology during infection. Taking together, we described the development of a non-human primate model of cryptococcosis that allowed us to perform an in-depth analysis and comparison of transcriptome profiles during infections of two animal models and conceptually identify host genes important in disease responses. This study provides new insights in understanding fungal pathogenesis mechanisms that potentially facilitate the identification of novel drug targets for the treatment of cryptococcal infection.

Fungal acetylome comparative analysis identifies an essential role of acetylation in human fungal pathogen virulence.

Lysine acetylation is critical in regulating important biological processes in many organisms, yet little is known about acetylome evolution and its contribution to phenotypic diversity. Here, we compare the acetylomes of baker's yeast and the three deadliest human fungal pathogens, Cryptococcus neoformans, Candida albicans, and Aspergillus fumigatus. Using mass spectrometry enriched for acetylated peptides together with public data from Saccharomyces cerevisiae, we show that fungal acetylomes are characterized by dramatic evolutionary dynamics and limited conservation in core biological processes. Notably, the levels of protein acetylation in pathogenic fungi correlate with their pathogenicity. Using gene knockouts and pathogenicity assays in mice, we identify deacetylases with critical roles in virulence and protein translation elongation. Finally, through mutational analysis of deactylation motifs we find evidence of positive selection at specific acetylation motifs in fungal pathogens. These results shed new light on the pathogenicity regulation mechanisms underlying the evolution of fungal acetylomes.

Optimization of ultrasonic-assisted extraction of pigment from Dioscorea cirrhosa by response surface methodology and evaluation of its stability.

Response surface methodology (RSM) was utilized to optimize the ultrasonic-assisted extraction (UAE) of Dioscorea cirrhosa pigment (DCP). The results demonstrated that the yield of DCP is the highest (32.27%) when acetone volume fraction is 74%, extraction time is 31 min, and the temperature is 54 °C. Next, the effects of pH, temperature, light, metal ions, reductants and oxidants on the stability of DCP were further evaluated to confirm the best storage conditions of DCP. The results showed that DCP should be stored at a wide pH range of 3 to 9, below 80 °C and away from light. Metal ions such as Fe2+, Fe3+, and Ti4+ can destabilize DCP, while K+, Al3+, Ca2+, Cu2+, Mg2+, and Zn2+ have little impact on DCP. Moreover, DCP showed good anti-reduction and poor anti-oxidization properties. These results might provide the basic data and theoretical guidance for the application of DCP.

Copper chelators promote nonamyloidogenic processing of AßPP via MT1/2 /CREB-dependent signaling pathways in AßPP/PS1 transgenic mice.

Copper is essential for the generation of reactive oxygen species (ROS), which are induced by amyloid-ß (Aß) aggregation; thus, the homeostasis of copper is believed to be a therapeutic target for Alzheimer's disease (AD). Although clinical trials of copper chelators show promise when applied in AD, the underlying mechanism is not fully understood. Here, we reported that copper chelators promoted nonamyloidogenic processing of AßPP through MT1/2 /CREB-dependent signaling pathways. First, we found that the formation of Aß plaques in the cortex was significantly reduced, and learning deficits were significantly improved in AßPP/PS1 transgenic mice by copper chelator tetrathiomolybdate (TM) administration. Second, TM and another copper chelator, bathocuproine sulfonate (BCS), promoted nonamyloidogenic processing of AßPP via inducing the expression of ADAM10 and the secretion of sAßPPα. Third, the inducible ADAM10 production caused by copper chelators can be blocked by a melatonin receptor (MT1/2 ) antagonist (luzindole) and a MT2 inhibitor (4-P-PDOT), suggesting that the expression of ADAM10 depends on the activation of MT1/2 signaling pathways. Fourth, three of the MT1/2 -downstream signaling pathways, Gq/PLC/MEK/ERK/CREB, Gs/cAMP/PKA/ERK/CREB and Gs/cAMP/PKA/CREB, were responsible for copper chelator-induced ADAM10 production. Based on these results, we conclude that copper chelators regulate the balance between amyloidogenic and nonamyloidogenic processing of AßPP via promoting ADAM10 expression through MT1/2 /CREB-dependent signaling pathways.

Tetrathiomolybdate Treatment Leads to the Suppression of Inflammatory Responses through the TRAF6/NFκB Pathway in LPS-Stimulated BV-2 Microglia.

Although the positive relationship between copper and Alzheimer's disease (AD) was reported by a lot of epidemiological data, the mechanism is not completely known. Copper is a redox metal and serves as a mediator of inflammation. Because the homeostasis of copper is altered in Aß precursor protein (APP) and presenilin 1 (PS1) transgenic (Tg) mice, the using of copper chelators is a potential therapeutic strategy for AD. Here we report that a copper chelator, tetrathiomolybdate (TM), is a potential therapeutic drug of AD. We investigated whether TM treatment led to a decrease of pro-inflammatory cytokines in vivo and in vitro, and found that TM treatment reduced the expression of iNOS and TNF-α in APP/PS1 Tg mice through up-regulating superoxide dismutase 1 (SOD1) activity. In vitro, once stimulated, microglia secretes a variety of proinflammatory cytokines, so we utilized LPS-stimulated BV-2 cells as the inflammatory cell model to detect the anti-inflammatory effects of TM. Our results indicated that TM-pretreatment suppressed the ubiquitination of TRAF6 and the activation of NFκB without affecting the expression of TLR4 and Myd88 in vitro. By detecting the activity of SOD1 and the production of reactive oxygen species (ROS), we found that the anti-inflammatory effects of TM could be attributed to its ability to reduce the amount of intracellular bioavailable copper, and the production of ROS which is an activator of the TRAF6 auto-ubiquitination. Hence, our results revealed that TM-treatment could reduce the production of inflammatory cytokines by the suppression of ROS/TRAF6/AKT/NFκB signaling pathway.

Deferoxamine-mediated up-regulation of HIF-1α prevents dopaminergic neuronal death via the activation of MAPK family proteins in MPTP-treated mice.

Accumulating evidence suggests that an abnormal accumulation of iron in the substantia nigra (SN) is one of the defining characteristics of Parkinson's disease (PD). Accordingly, the potential neuroprotection of Fe chelators is widely acknowledged for the treatment of PD. Although desferrioxamine (DFO), an iron chelator widely used in clinical settings, has been reported to improve motor deficits and dopaminergic neuronal survival in animal models of PD, DFO has poor penetration to cross the blood-brain barrier and elicits side effects. We evaluated whether an intranasal administration of DFO improves the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced degeneration of dopaminergic neurons in the nigrostriatal axis and investigated the molecular mechanisms of intranasal DFO treatment in preventing MPTP-induced neurodegeneration. Treatment with DFO efficiently alleviated behavioral deficits, increased the survival of tyrosine hydroxylase (TH)-positive neurons, and decreased the action of astrocytes in the SN and striatum in an MPTP-induced PD mouse model. Interestingly, we found that DFO up-regulated the expression of HIF-1α protein, TH, vascular endothelial growth factor (VEGF), and growth associated protein 43 (GAP43) and down-regulated the expression of α-synuclein, divalent metal transporter with iron-responsive element (DMT1+IRE), and transferrin receptor (TFR). This was accompanied by a decrease in iron-positive cells in the SN and striatum of the DFO-treated group. We further revealed that DFO treatment significantly inhibited the MPTP-induced phosphorylation of the c-Jun N-terminal kinase (JNK) and differentially enhanced the phosphorylation of extracellular regulated protein kinases (ERK) and mitogen-activated protein kinase (MAPK)/P38 kinase. Additionally, the effects of DFO on increasing the Bcl-2/Bax ratio were further validated in vitro and in vivo. In SH-SY5Y cells, the DFO-mediated up-regulation of HIF-1α occurred via the activation of the ERK and P38MAPK signaling pathway. Collectively, the present data suggest that intranasal DFO treatment is effective in reversing MPTP-induced brain abnormalities and that HIF-1-pathway activation is a potential therapy target for the attenuation of neurodegeneration.

Intranasal deferoxamine attenuates synapse loss via up-regulating the P38/HIF-1α pathway on the brain of APP/PS1 transgenic mice.

The widely recognized neuroprotective effect of iron chelators is contributed by their ability to prevent reactive oxygen species (ROS) generation via the Fenton reaction, which sequesters redox-active Fe. An additional neuroprotective mechanism of iron-chelating compounds is to regulate the transcriptional activator hypoxia-inducible factor 1α (HIF-1α). In the present study, we observed that intranasal administration of deferoxamine decreased beta-amyloid (Aß) deposition and rescued synapse loss in the brain of Aß precursor protein and presenilin-1 (APP/PS1) double transgenic mice. We found that deferoxamine (DFO) up-regulated HIF-1α mRNA expression and its protein level, and further induced the proteins that are encoded from HIF-1-adaptive genes, including transferrin receptor (TFR), divalent metal transporter 1 (DMT1), and brain-derived neurotrophic factor (BDNF). The effects of DFO on the induction and stabilization of HIF-1α were further confirmed in vitro. This was accompanied by a decrease of Fe in the CA3 region of the hippocampus. Western blotting studies revealed that DFO differentially enhanced the phosphorylation of mitogen-activated protein kinase (MAPK)/P38 kinase in vitro and in vivo. The results suggest that the DFO may up-regulate several HIF-1-dependent neuroprotective-adaptive genes in AD via activating P38/HIF-1α pathway, which may serve as important therapeutic targets to the disease.