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Phagocytosis plays diverse roles in biology, but our understanding of the purpose, interplay, and cell signaling mechanisms associated with different modes of phagocytosis is limited, without being able to capture and visualize each step in this rapid process from the beginning to end. A new study by Walbaum et al. uses stunning time-lapse 3D imaging of the engulfment of erythrocytes by macrophages via sinking, ruffling, and cup formation, unequivocally confirming a visionary 44-year-old theory derived from still electron microscopy photos that phagocytosis mediated by complement receptor CR3 occurs via a sinking mechanism and antibodymediated phagocytosis occurs via phagocytic cup formation. The article also challenges the dogma, showing that phagocytic cup formation is not unique to antibody receptor phagocytosis, rather CR3 plays a complex role in different modes of phagocytosis. For example, inhibition of antibody-mediated phagocytosis leads to a compensatory upregulation of CR3-mediated sinking phagocytosis. These findings animate, in vivid colors, processes previously only captured as stills, exposing interactions between different phagocytic mechanisms and altering our basic understanding of this important process. [ABSTRACT FROM AUTHOR]

Non-steroidal anti-inflammatory agents (NSAIDs) are associated with a marked reduction in the risk of developing Alzheimer's disease, a form of dementia characterized by the accumulation of amyloid plaques containing the amyloid-beta protein (Abeta). Studies of the effects of NSAIDs upon the inflammatory response surrounding amyloid plaques and upon the generation of Abeta from the amyloid precursor protein (APP) have led to two proposed mechanisms by which NSAIDs may protect against Alzheimer's disease: one, the selective lowering of Abeta42 by a subset of NSAIDs; and two, the reduction of inflammation. Although Alzheimer's disease is a disorder of brain and synaptic function, the effects of NSAIDs on Abeta-mediated suppression of synaptic plasticity and memory function have never been reported. We therefore investigated how three different NSAIDs, chosen for their distinct effects on Abeta42 production and the inhibition of the cyclooxygenase (COX) isoenzymes, COX-1 and COX-2, affect memory function and synaptic plasticity. By focusing upon brain and synapse function, we made novel observations about the effects of NSAIDs on Abeta-mediated neural processes. Here we report that the selective inhibition of COX-2, but not COX-1, acutely prevented the suppression of hippocampal long-term plasticity (LTP) by Abeta. The non-selective NSAIDs, ibuprofen and naproxen, and a selective COX-2 inhibitor, MF-tricyclic, each restored memory function in Tg2576 mice over-expressing APP, and also blocked Abeta-mediated inhibition of LTP. There was no advantage of ibuprofen, a selective Abeta42-lowering agent (SALA), over the non-SALAs, naproxen and MF-tricyclic. The beneficial effects on memory did not depend upon lowered levels of Abeta42 or the inflammatory cytokines, tumour necrosis factor alpha (TNF-alpha) and interleukin 1beta (IL-1beta). Intriguingly, improved memory function was inversely related to prostaglandin E2 (PGE2) levels. Conversely, exogenous PGE2 prevented the restorative effects of COX-2 inhibitors on LTP. The data indicate that the inhibition of COX-2 blocks Abeta-mediated suppression of LTP and memory function, and that this block occurs independently of reductions in Abeta42 or decreases in inflammation. The results lead us to propose a third possible mechanism by which NSAIDs may protect against Alzheimer's disease, involving the blockade of a COX-2-mediated PGE2 response at synapses. [ABSTRACT FROM AUTHOR]

Apolipoprotein J (apoJ; also known as clusterin and sulfated glycoprotein (SGP)-2) is associated with senile plaques in degenerating regions of Alzheimer's disease brains, where activated microglia are also prominent. We show a functional link between apoJ and activated microglia by demonstrating that exogenous apoJ activates rodent microgliain vivoandin vitro. Intracerebroventricular infusion of purified human plasma apoJ (∼4 µg over 28 days) activated parenchymal microglia to a phenotype characterized by enlarged cell bodies and processes (phosphotyrosine immunostaining).In vitro, primary rat microglia were also activated by apoJ, with changes in morphology and induction of major histocompatibility complex class II (MHCII) antigen. ApoJ increased the secretion of reactive nitrogen intermediates in a dose-dependent manner (EC50 112 nm), which was completely blocked by aminoguanidine (AG), a nitric oxide synthase inhibitor. However, AG did not block the increased secretion of tumor necrosis factor-α by apoJ (EC50 55 nm). Microglial activation by apoJ was also blocked by an anti-apoJ monoclonal antibody (G7), and by chemical cleavage of apoJ with 2-nitro-5-thiocyanobenzoate. The mitogen-activated protein kinase kinase and protein kinase C inhibitors PD98059 and H7 inhibited apoJ-mediated induction of reactive nitrogen intermediate secretion from cultured microglia. As a functional measure, apoJ-activated microglia secreted neurotoxic agents in a microglia–neuron co-culture model. We hypothesize that ApoJ contributes to chronic inflammation and neurotoxicity through direct effects on microglia. [ABSTRACT FROM AUTHOR]

Abstract Backgound No disease modifying treatment currently exists for Huntington's disease (HD), a fatal neurodegenerative disorder characterized by the formation of amyloid-like aggregates of the mutated huntingtin protein. Curcumin is a naturally occurring polyphenolic compound with Congo red-like amyloid binding properties and the ability to cross the blood brain barrier. CAG140 mice, a knock-in (KI) mouse model of HD, display abnormal aggregates of mutant huntingtin and striatal transcriptional deficits, as well as early motor, cognitive and affective abnormalities, many months prior to exhibiting spontaneous gait deficits, decreased striatal volume, and neuronal loss. We have examined the ability of life-long dietary curcumin to improve the early pathological phenotype of CAG140 mice. Results KI mice fed a curcumin-containing diet since conception showed decreased huntingtin aggregates and increased striatal DARPP-32 and D1 receptor mRNAs, as well as an amelioration of rearing deficits. However, similar to other antioxidants, curcumin impaired rotarod behavior in both WT and KI mice and climbing in WT mice. These behavioral effects were also noted in WT C57Bl/6 J mice exposed to the same curcumin regime as adults. However, neither locomotor function, behavioral despair, muscle strength or food utilization were affected by curcumin in this latter study. The clinical significance of curcumin's impairment of motor performance in mice remains unclear because curcumin has an excellent blood chemistry and adverse event safety profile, even in the elderly and in patients with Alzheimer's disease. Conclusion Together with this clinical experience, the improvement in several transgene-dependent parameters by curcumin in our study supports a net beneficial effect of dietary curcumin in HD.

The article presents an abstract of the study titled "Structure and Function of Hippocampal and Entorhinal Synapses in Memory-impaired Transgenic Mice Expressing Mutant Amyloid Precursor Protein." The study concludes that some discreet structural abnormalities in synapses develop as mice age. The paper will be presented during the 30th Annual Meeting of the American Society for Neurochemistry, in New Orleans, Louisiana, from March 14-17, 1999.

Amyloid fibrils of tau are increasingly accepted as a cause of neuronal death and brain atrophy in Alzheimer's disease (AD). Diminishing tau aggregation is a promising strategy in the search for efficacious AD therapeutics. Previously, our laboratory designed a six-residue, nonnatural amino acid inhibitor D-TLKIVW peptide (6-DP), which can prevent tau aggregation in vitro. However, it cannot block cell-to-cell transmission of tau aggregation. Here, we find D-TLKIVWC (7-DP), a d-cysteine extension of 6-DP, not only prevents tau aggregation but also fragments tau fibrils extracted from AD brains to neutralize their seeding ability and protect neuronal cells from tau-induced toxicity. To facilitate the transport of 7-DP across the blood-brain barrier, we conjugated it to magnetic nanoparticles (MNPs). The MNPs-DP complex retains the inhibition and fragmentation properties of 7-DP alone. Ten weeks of MNPs-DP treatment appear to reverse neurological deficits in the PS19 mouse model of AD. This work offers a direction for development of therapies to target tau fibrils.

The substantia nigra is generally considered to show significant cell loss not only in Parkinson's but also in Alzheimer's disease, conditions that share several neuropathological traits. An interesting feature of this nucleus is that the pars compacta dopaminergic neurons contain acetylcholinesterase (AChE). Independent of its enzymatic role, this protein is released from pars reticulata dendrites, with effects that have been observed in vitro, ex vivo and in vivo. The part of the molecule responsible for these actions has been identified as a 14-mer peptide, T14, cleaved from the AChE C-terminus and acting at an allosteric site on alpha-7 nicotinic receptors, with consequences implicated in neurodegeneration. Here, we show that free T14 is co-localized with tyrosine hydroxylase in rodent pars compacta neurons. In brains with Alzheimer's pathology, the T14 immunoreactivity in these neurons increases in density as their number decreases with the progression of the disease. To explore the functional implications of raised T14 levels in the substantia nigra, the effect of exogenous peptide on electrically evoked neuronal activation was tested in rat brain slices using optical imaging with a voltage-sensitive dye (Di-4-ANEPPS). A significant reduction in the activation response was observed; this was blocked by the cyclized variant of T14, NBP14. In contrast, no such effect of the peptide was seen in the striatum, a region lacking the T14 target, alpha-7 receptors. These findings add to the accumulating evidence that T14 is a key signaling molecule in neurodegenerative disorders and that its antagonist NBP14 has therapeutic potential.

Introduction: The neuronal mechanism driving Alzheimer's disease (AD) is incompletely understood., Methods: Immunohistochemistry, pharmacology, biochemistry, and behavioral testing are employed in two pathological contexts-AD and a transgenic mouse model-to investigate T14, a 14mer peptide, as a key signaling molecule in the neuropathology., Results: T14 increases in AD brains as the disease progresses and is conspicuous in 5XFAD mice, where its immunoreactivity corresponds to that seen in AD: neurons immunoreactive for T14 in proximity to T14-immunoreactive plaques. NBP14 is a cyclized version of T14, which dose-dependently displaces binding of its linear counterpart to alpha-7 nicotinic receptors in AD brains. In 5XFAD mice, intranasal NBP14 for 14 weeks decreases brain amyloid and restores novel object recognition to that in wild-types., Discussion: These findings indicate that the T14 system, for which the signaling pathway is described here, contributes to the neuropathological process and that NBP14 warrants consideration for its therapeutic potential., Competing Interests: Susan Greenfield is the founder and CEO of Neuro‐Bio Limited and holds shares in the Company. She is the inventor in all Neuro‐Bio patents. Neuro‐Bio has a patent portfolio that currently includes 15 patent families (granted patents in Australia ( AU), China (CN), Europe (EP), Japan (JP), Mexico (MX), and United States of America (USA)). The bulk of this patent protection is in the field of neurodegeneration and, in particular, Alzheimer's disease. Of these, there are granted patents (in AU x2, CN, EP, JP, MX, and USA) and pending patent applications (in Brazil (BR), Canada (CA), India (IN), Republic of Korea (KR), New Zeland (NZ), and South Africa (ZA)) all based on WO2015/004430 (use of cyclic peptides from the C‐terminus of AChE for the diagnosis, prevention and treatment of neurodegeneration). In addition, Neuro‐Bio has a published international patent application with 12 corresponding national phases at different stages of prosecution based on each of WO2016/083809 (Novel linear peptides for treating neurodegeneration); WO2018/033724 (Peptidomimetics for treating Alzheimer's disease); and WO2016/156803 (Antibody that recognizes the T14 peptide of AChE). Neuro‐Bio also has published international patent application based on WO2018/178665 (Quantitative predictive biomarker for predicting cognitive decline) with national phases proceeding in the USA and EP. Neuro‐Bio additionally has an unpublished UK patent application drawn to Braak staging and positron emision tomography (PET) scanning for diagnosing Alzheimer's disease, and an unpublished international patent cooperation treaty (PCT) application protecting an in vivo animal model of Alzheimer's disease for testing novel therapies. In addition to Neuro‐Bio's core focus of detection and therapy of neurodegenerative disorders (in particular, Alzheimer's disease), it has two patent families concerning cancer and metastasis, that is, WO2017/130003 (diagnosing cancer) and WO2015/054068 (treating cancer with cyclic peptides), both of which have 12 national phases currently pending. All are owned by Neuro‐Bio with no encumbrance. Recent inventions have led to patent applications relating to various skin conditions. Neuro‐Bio has also recently filed a United Kingdom (UK) patent application for the treatment of Down's syndrome. Susan Greenfield is a member of the House of Lords in the United Kingdom's Parliament; this is a non‐stipendiary appointment. Clive Coen holds shares in the company and sits on the Neuro‐Bio Science Advisory Board (non‐stipendiary). He is Editor of Neuroendocrinology and the Chair of the Rationalist Association [UK]; neither of these entities has made payments to him or his institution. His research has been supported by the Biotechnology and Biological Sciences Research Council. Sara Garcia‐Ratés, Paul Morrill, Owen Hollings, Matthew Passmore, and Sibah Hasan are employees of Neuro‐Bio. Gregory Cole and his colleagues at University of California, Los Angeles (UCLA) (Sally Fraustchy, Ram P Singh, and Marisa Mekkittikul), have received partial support for consumables from Neuro‐Bio. Nikisha Carty, Silvia Bison, Laura Piccoli, Renzo Carletti, Stephano Tacconi, Anna Chalidou, Matthew Pedercini, Tim Kroecher, Hubert Astner, and Philip Gerrard are employees of Evotec. Evotec, a provider of scientific expertise to the global health care industry and academia, was contracted by Neuro‐Bio to undertake the behavioral part of the project and the immunohistochemical studies on amyloid. In the past 36 months, Gregory Cole has received grants and contracts: Veterans administration (VA) Merit BX004332, 2019‐2023 (Cole Principal Investigator (PI)): Tauopathy in mice and humans: surrogate plasma biomarkers for brain trauma‐initiated neurodegenerative disease. Akros/Japan Tobacco Contract, 2018‐2020 (Cole PI): Enhancing pyruvate dehydrogenase activity. NIH NIA R01AG057658, 2017‐2022 (Cole Co‐PI): Treating Alzheimer's disease by reducing brain insulin resistance with incretin receptor agonists. AstraZeneca NCR‐19‐14517, 2019‐2020 (Ajit Divakaruni PI; Cole Co‐I): Determining the role of brain nutrient preference in cognitive impairment and AD. National Neurological Aids Bank 3U24MH100929‐08S1, 2021‐2023 (Elyse Singer PI; Cole Co‐I): Alzheimer's related biomarker neuropathology in HIV post‐mortem brains. NIH/NIA R21 AG069100‐01, 2020 (Qiulan Ma PI; Cole Co‐I): Modulation of TGF‐beta signaling by omega‐6 polyunsaturated fatty acids for treating Alzheimer's disease. NIH NINR R01NR017190‐03, 2020‐2021 (Sarah Choi & Rajesh Kumar MPI; Cole Co‐I): Relationships between brain tissue integrity and self‐care abilities in adults with type 2 diabetes administrative supplement. Michael J Fox Foundation, 2021 (David Eisenberg PI; Cole Co‐I): Completion of pre‐clinical study of a safe and effective image‐based biomarker for Parkinson's disease. Michael J Fox Foundation, 2021‐2022 (Sally Frautschy PI; Cole Co‐I): Liganded nanoparticles to inhibit alpha‐synuclein aggregate deficits in endosomal/lysosomal/autophagy. In the past 36 months, Gregory Cole has received royalties or licenses from a curcumin formulation patent and Ram Singh has received consulting fees from UCLA., (© 2022 The Authors. Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring published by Wiley Periodicals, LLC on behalf of Alzheimer's Association.)

Introduction: Retinal imaging is a non-invasive tool to study both retinal vasculature and neurodegeneration. In this exploratory retinal curcumin-fluorescence imaging (RFI) study, we sought to determine whether retinal vascular features combined with retinal amyloid burden correlate with the neurocognitive status., Methods: We used quantitative RFI in a cohort of patients with cognitive impairment to automatically compute retinal amyloid burden. Retinal blood vessels were segmented, and the vessel tortuosity index (VTI), inflection index, and branching angle were quantified. We assessed the correlations between retinal vascular and amyloid parameters, and cognitive domain Z-scores using linear regression models., Results: Thirty-four subjects were enrolled and twenty-nine (55% female, mean age 64 ± 6 years) were included in the combined retinal amyloid and vascular analysis. Eleven subjects had normal cognition and 18 had impaired cognition. Retinal VTI was discriminated among cognitive scores. The combined proximal mid-periphery amyloid count and venous VTI index exhibited significant differences between cognitively impaired and cognitively normal subjects (0.49 ± 1.1 vs. 0.91 ± 1.4, p = 0.006), and correlated with both the Wechsler Memory Scale-IV and SF-36 mental component score Z-scores ( p < 0.05)., Conclusion: This pilot study showed that retinal venular VTI combined with the proximal mid-periphery amyloid count could predict verbal memory loss. Future research is needed to finesse the clinical application of this retinal imaging-based technology.

Subcortical white matter ischemic lesions are increasingly recognized to have pathologic overlap in individuals with Alzheimer's disease (AD). The interaction of white matter ischemic lesions with amyloid pathology seen in AD is poorly characterized. We designed a novel mouse model of subcortical white matter ischemic stroke and AD that can inform our understanding of the cellular and molecular mechanisms of mixed vascular and AD dementia. Subcortical white matter ischemic stroke underlying forelimb motor cortex was induced by local stereotactic injection of an irreversible eNOS inhibitor. Subcortical white matter ischemic stroke or sham procedures were performed on human ApoE4-targeted-replacement (TR):5XFAD mice at 8 weeks of age. Behavioral tests were done at 7, 10, 15, and 20 weeks. A subset of animals underwent 18 FDG-PET/CT. At 20 weeks of age, brain tissue was examined for amyloid plaque accumulation and cellular changes. Compared with sham E4-TR:5XFAD mice, those with an early subcortical ischemic stroke showed a significant reduction in amyloid plaque burden in the region of cortex overlying the subcortical stroke. Cognitive performance was improved in E4-TR:5XFAD mice with stroke compared with sham E4-TR:5XFAD animals. Iba-1+ microglial cells in the region of cortex overlying the subcortical stroke were increased in number and morphologic complexity compared with sham E4-TR:5XFAD mice, suggesting that amyloid clearance may be promoted by an interaction between activated microglia and cortical neurons in response to subcortical stroke. This novel approach to modeling mixed vascular and AD dementia provides a valuable tool for dissecting the molecular interactions between these two common pathologies.

Introduction: Despite advances in imaging retinal amyloidosis, a quantitative and topographical investigation of retinal amyloid beta burden in patients with cognitive decline has never been reported., Methods: We used the specific amyloid-binding fluorophore curcumin and laser ophthalmoscopy to assess retinal amyloid imaging (RAI) in 34 patients with cognitive decline. We automatically quantified retinal amyloid count (RAC) and area in the superotemporal retinal sub-regions and performed correlation analyses with cognitive and brain volumetric parameters., Results: RAC significantly and inversely correlated with hippocampal volume (HV; r = -0.39, P  = .04). The proximal mid-periphery (PMP) RAC and RA areas were significantly greater in patients with Montreal Cognitive Assessment (MOCA) score < 26 ( P  = .01; Cohen d = 0.83 and 0.81, respectively). PMP showed significantly more RAC and area in subjects with amnestic mild cognitive impairment (MCI) and Alzheimer's disease (AD) compared to cognitively normal ( P  = .04; Cohen d = 0.83)., Conclusion: Quantitative RAI is a feasible technique and PMP RAC may predict HV. Future larger studies should determine RAI's potential as a biomarker of early AD., Competing Interests: Keith L. Black, Steven Verdooner, Yosef Koronyo, and Maya Koronyo‐Hamaoui are co‐founding members of NeuroVision Imaging Inc. Keith L. Black, Steven Verdooner, and Czeszynski Alan D are in leading roles in NeuroVision Imaging Inc. Keith L. Black, Steven Verdooner, Yosef Koronyo, and Maya Koronyo‐Hamaoui are co‐inventors of US patents related to retinal imaging and Alzheimer's disease. Sally Frautschy is co‐inventor on US patent US9192644B2 for a curcumin formulation and is a co‐founding member of Optimized Curcumin Longvida. Other authors declare no conflict., (© 2020 The Authors. Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring published by Wiley Periodicals, LLC on behalf of Alzheimer's Association.)

Alzheimer's disease (AD) genetics implies a causal role for innate immune genes, TREM2 and CD33, products that oppose each other in the downstream Syk tyrosine kinase pathway, activating microglial phagocytosis of amyloid (Aβ). We report effects of low (Curc-lo) and high (Curc-hi) doses of curcumin on neuroinflammation in APPsw transgenic mice. Results showed that Curc-lo decreased CD33 and increased TREM2 expression (predicted to decrease AD risk) and also increased TyroBP, which controls a neuroinflammatory gene network implicated in AD as well as phagocytosis markers CD68 and Arg1. Curc-lo coordinately restored tightly correlated relationships between these genes' expression levels, and decreased expression of genes characteristic of toxic pro-inflammatory M1 microglia (CD11b, iNOS, COX-2, IL1β). In contrast, very high dose curcumin did not show these effects, failed to clear amyloid plaques, and dysregulated gene expression relationships. Curc-lo stimulated microglial migration to and phagocytosis of amyloid plaques both in vivo and in ex vivo assays of sections of human AD brain and of mouse brain. Curcumin also reduced levels of miR-155, a micro-RNA reported to drive a neurodegenerative microglial phenotype. In conditions without amyloid (human microglial cells in vitro, aged wild-type mice), Curc-lo similarly decreased CD33 and increased TREM2. Like curcumin, anti-Aβ antibody (also reported to engage the Syk pathway, increase CD68, and decrease amyloid burden in human and mouse brain) increased TREM2 in APPsw mice and decreased amyloid in human AD sections ex vivo. We conclude that curcumin is an immunomodulatory treatment capable of emulating anti-Aβ vaccine in stimulating phagocytic clearance of amyloid by reducing CD33 and increasing TREM2 and TyroBP, while restoring neuroinflammatory networks implicated in neurodegenerative diseases., (Published by Elsevier Inc.)

Background: Noninvasive detection of Alzheimer's disease (AD) with high specificity and sensitivity can greatly facilitate identification of at-risk populations for earlier, more effective intervention. AD patients exhibit a myriad of retinal pathologies, including hallmark amyloid β-protein (Aβ) deposits., Methods: Burden, distribution, cellular layer, and structure of retinal Aβ plaques were analyzed in flat mounts and cross sections of definite AD patients and controls (n = 37). In a proof-of-concept retinal imaging trial (n = 16), amyloid probe curcumin formulation was determined and protocol was established for retinal amyloid imaging in live patients., Results: Histological examination uncovered classical and neuritic-like Aβ deposits with increased retinal Aβ42 plaques (4.7-fold; P = 0.0063) and neuronal loss (P = 0.0023) in AD patients versus matched controls. Retinal Aβ plaque mirrored brain pathology, especially in the primary visual cortex (P = 0.0097 to P = 0.0018; Pearson's r = 0.84-0.91). Retinal deposits often associated with blood vessels and occurred in hot spot peripheral regions of the superior quadrant and innermost retinal layers. Transmission electron microscopy revealed retinal Aβ assembled into protofibrils and fibrils. Moreover, the ability to image retinal amyloid deposits with solid-lipid curcumin and a modified scanning laser ophthalmoscope was demonstrated in live patients. A fully automated calculation of the retinal amyloid index (RAI), a quantitative measure of increased curcumin fluorescence, was constructed. Analysis of RAI scores showed a 2.1-fold increase in AD patients versus controls (P = 0.0031)., Conclusion: The geometric distribution and increased burden of retinal amyloid pathology in AD, together with the feasibility to noninvasively detect discrete retinal amyloid deposits in living patients, may lead to a practical approach for large-scale AD diagnosis and monitoring., Funding: National Institute on Aging award (AG044897) and The Saban and The Marciano Family Foundations.

The intra- and extracellular accumulation of misfolded and aggregated amyloid proteins is a common feature in several neurodegenerative diseases, which is thought to play a major role in disease severity and progression. The principal machineries maintaining proteostasis are the ubiquitin proteasomal and lysosomal autophagy systems, where heat shock proteins play a crucial role. Many protein aggregates are degraded by the lysosomes, depending on aggregate size, peptide sequence, and degree of misfolding, while others are selectively tagged for removal by heat shock proteins and degraded by either the proteasome or phagosomes. These systems are compromised in different neurodegenerative diseases. Therefore, developing novel targets and classes of therapeutic drugs, which can reduce aggregates and maintain proteostasis in the brains of neurodegenerative models, is vital. Natural products that can modulate heat shock proteins/proteosomal pathway are considered promising for treating neurodegenerative diseases. Here we discuss the current knowledge on the role of HSPs in protein misfolding diseases and knowledge gained from animal models of Alzheimer's disease, tauopathies, and Huntington's diseases. Further, we discuss the emerging treatment regimens for these diseases using natural products, like curcumin, which can augment expression or function of heat shock proteins in the cell.

Oligomerization of the amyloid β-protein (Aβ) is a seminal event in Alzheimer's disease. Aβ42, which is only two amino acids longer than Aβ40, is particularly pathogenic. Why this is so has not been elucidated fully. We report here results of computational and experimental studies revealing a C-terminal turn at Val36-Gly37 in Aβ42 that is not present in Aβ40. The dihedral angles of residues 36 and 37 in an Ile31-Ala42 peptide were consistent with β-turns, and a β-hairpin-like structure was indeed observed that was stabilized by hydrogen bonds and by hydrophobic interactions between residues 31-35 and residues 38-42. In contrast, Aβ(31-40) mainly existed as a statistical coil. To study the system experimentally, we chemically synthesized Aβ peptides containing amino acid substitutions designed to stabilize or destabilize the hairpin. The triple substitution Gly33Val-Val36Pro-Gly38Val ("VPV") facilitated Aβ42 hexamer and nonamer formation, while inhibiting formation of classical amyloid-type fibrils. These assemblies were as toxic as were assemblies from wild-type Aβ42. When substituted into Aβ40, the VPV substitution caused the peptide to oligomerize similarly to Aβ42. The modified Aβ40 was significantly more toxic than Aβ40. The double substitution d-Pro36-l-Pro37 abolished hexamer and dodecamer formation by Aβ42 and produced an oligomer size distribution similar to that of Aβ40. Our data suggest that the Val36-Gly37 turn could be the sine qua non of Aβ42. If true, this structure would be an exceptionally important therapeutic target., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

This review will focus primarily on the role of the low density lipoprotein receptor-related protein (LRP-1) in neuronal synapse formation and function in Alzheimer's Disease (AD). We review the role that its ligands may have in cognition or AD: apolipoprotein E (ApoE), alpha2-macroglobulin, Transforming Growth Factor-Beta (TGFbeta, Tissue Plasminogen Activator (tPA), insulin growth factor binding protein-3 (IGFBP-3), which all bind LRP-1 and apolipoprotein J (ApoJ), which is a ligand for LRP-2. After reviewing its role as a signaling receptor, we discuss the connection between LRP and the NMDA glutamate receptor via the post synaptic density 95 (PSD-95) neuronal scaffold protein and the implications it may have for memory and cognition. Finally, we discuss the evidence supporting a role for LRP in AD. Although the evidence for LRP as a genetic risk factor is weak, many of its ligands impose genetic risk, and have been implicated in AD pathogenic cascades. We discuss the role of LRP in amyloid precursor protein (APP) processing and production of beta-amyloid (Abeta. We identify LRP ligands that accelerate aggregation of toxic Abeta species. LRP mediates crucial pathways in AD pathogenesis such as Abeta clearance, Abeta uptake, intraneuronal Abeta accumulation and Abeta-associated neuron death. Interestingly, the TGFbeta -V receptor is LRP-1. Data show that one critical ligand TGFbeta2, associated with neurodegeneration in amyloid diseases, induces LRP expression in PC12 cells. Data from rodent infusion models demonstrate the impact of TGFbeta2 in modifying Abeta- induced Long Term Potentiation (LTP) responses, presynaptic proteins, lipid peroxidation, gliosis and staining for neuronal nuclei. The evidence supports a complex and significant role of LRP in cognition and AD.

The accumulation of fibrillar aggregates of beta Amyloid (A beta) in Alzheimer's Disease (AD) brain is associated with chronic brain inflammation. Although activated microglia (mu glia) can potentially clear toxic amyloid, chronic activation may lead to excessive production of neurotoxins. Recent epidemiological and clinical data have raised questions about the use of anti-inflammatory steroids (glucocorticoids, Gcs) and estrogens for treatment or prevention of AD. Since very little is known about steroid effects on mu glial interactions with amyloid, we investigated the effects of the synthetic Gc dexamethasone (DXM) and 17-beta estradiol (E2) in vitro in a murine mu glial-like N9 cell line on toxin production and intracellular A beta accumulation. To determine whether the steroid alterations of A beta uptake in vitro had relevance in vivo, we examined the effects of these steroids on A beta accumulation and mu glial responses to A beta infused into rat brain. Our in vitro data demonstrate for the first time that Gc dose-dependently enhanced mu glial A beta accumulation and support previous work showing that E2 enhances A beta uptake. Despite both steroids enhancing uptake, degradation was impeded, particularly with Gcs. Distinct differences between the two steroids were observed in their effect on toxin production and cell viability. Gc dose-dependently increased toxicity and potentiated A beta induction of nitric oxide, while E2 promoted cell viability and inhibited A beta induction of nitric oxide. The steroid enhancement of mu glial uptake and impedence of degradation observed in vitro were consistent with observations from in vivo studies. In the brains of A beta-infused rats, the mu glial staining in entorhinal cortex layer 3, not associated with A beta deposits was increased in response to A beta infusion and this effect was blocked by feeding rats prednisolone. In contrast, E2 enhanced mu glial staining in A beta-infused rats. A beta-immunoreactive (ir) deposits were quantitatively smaller, appeared denser, and were associated with robust mu glial responses. Despite the fact that steroid produced a smaller more focal deposit, total extracted A beta in cortical homogenate was elevated. Together, the in vivo and in vitro data support a role for steroids in plaque compaction. Our data are also consistent with the hypothesis that although E2 is less potent than Gc in impeding A beta degradation, long term exposure to both steroids could reduce A beta clearance and clinical utility. These data showing Gc potentiation of A beta-induced mu glial toxins may help explain the lack of epidemiological correlation for AD. The failure of both steroids to accelerate A beta degradation may explain their lack of efficacy for treatment of AD.

Inflammation in Alzheimer's disease (AD) patients is characterized by increased cytokines and activated microglia. Epidemiological studies suggest reduced AD risk associates with long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs). Whereas chronic ibuprofen suppressed inflammation and plaque-related pathology in an Alzheimer transgenic APPSw mouse model (Tg2576), excessive use of NSAIDs targeting cyclooxygenase I can cause gastrointestinal, liver, and renal toxicity. One alternative NSAID is curcumin, derived from the curry spice turmeric. Curcumin has an extensive history as a food additive and herbal medicine in India and is also a potent polyphenolic antioxidant. To evaluate whether it could affect Alzheimer-like pathology in the APPSw mice, we tested a low (160 ppm) and a high dose of dietary curcumin (5000 ppm) on inflammation, oxidative damage, and plaque pathology. Low and high doses of curcumin significantly lowered oxidized proteins and interleukin-1beta, a proinflammatory cytokine elevated in the brains of these mice. With low-dose but not high-dose curcumin treatment, the astrocytic marker GFAP was reduced, and insoluble beta-amyloid (Abeta), soluble Abeta, and plaque burden were significantly decreased by 43-50%. However, levels of amyloid precursor (APP) in the membrane fraction were not reduced. Microgliosis was also suppressed in neuronal layers but not adjacent to plaques. In view of its efficacy and apparent low toxicity, this Indian spice component shows promise for the prevention of Alzheimer's disease.

Inflammation clearly occurs in pathologically vulnerable regions of the Alzheimer's disease (AD) brain, and it does so with the full complexity of local peripheral inflammatory responses. In the periphery, degenerating tissue and the deposition of highly insoluble abnormal materials are classical stimulants of inflammation. Likewise, in the AD brain damaged neurons and neurites and highly insoluble amyloid beta peptide deposits and neurofibrillary tangles provide obvious stimuli for inflammation. Because these stimuli are discrete, microlocalized, and present from early preclinical to terminal stages of AD, local upregulation of complement, cytokines, acute phase reactants, and other inflammatory mediators is also discrete, microlocalized, and chronic. Cumulated over many years, direct and bystander damage from AD inflammatory mechanisms is likely to significantly exacerbate the very pathogenic processes that gave rise to it. Thus, animal models and clinical studies, although still in their infancy, strongly suggest that AD inflammation significantly contributes to AD pathogenesis. By better understanding AD inflammatory and immunoregulatory processes, it should be possible to develop anti-inflammatory approaches that may not cure AD but will likely help slow the progression or delay the onset of this devastating disorder.

We evaluated the relationship between amyloid-beta protein (A beta) concentration and the metabolic abnormality in an Alzheimer's disease (AD) patient as measured by [18F]fluorodeoxyglucose positron emission tomography (FDG-PET). Across most regions there were significant inverse correlations among FDG-PET intensity values and both insoluble. The temporal lobe samples showed no significant correlation between FDG-PET values and A beta deposition. Findings support A beta as contributing to the hypometabolism in regions of the AD brain that are still relatively viable metabolically; those regions with chronic pathologic damage, such as temporal cortex, may have other factors that contribute to metabolic deficits.

An inflammatory response involving activated microglia in neuritic beta-amyloid plaques is found in Alzheimer's disease (AD) brain. Because HDL lipoproteins have been shown to carry the beta-amyloid peptide (Abeta) in plasma and CSF, we have investigated the influence of plasma high-density lipoprotein (HDL) and lipidated ApoE and ApoJ particles on the interaction of cultured rat microglia with Abeta1-42. Microglia degraded Abeta via a pathway sensitive to cytochalasin D and the scavenger receptor inhibitor, fucoidan. HDL increased the degradation of Abeta and the ratio of multimeric/monomeric Abeta in a dose-dependent manner. In contrast, lipidated ApoJ and ApoE decreased the degradation of Abeta, and the effects were ApoE isoform-dependent. Immuno-electron microscopy revealed internalized Abeta in endosomes and lysosomes as well as cell-associated Abeta in deep invaginations, which may be related to caveolae and surface-connected compartments. These data suggest that lipoprotein-dependent Abeta trafficking to microglia could be relevant to plaque pathogenesis in AD., (Copyright 1999 Wiley-Liss, Inc.)

A role for apolipoprotein E is implicated in regeneration of synaptic circuitry after neural injury. The in vitro mouse organotypic hippocampal slice culture system shows Timm's stained mossy fiber sprouting into the dentate gyrus molecular layer in response to deafferentation of the entorhinal cortex. We show that cultures derived from apolipoprotein E knockout mice are defective in this sprouting response; specifically, they show no sprouting in the dorsal region of the dentate gyrus, yet retain sprouting in the ventral region. Dorsal but not ventral sprouting in cultures from C57B1/6J mice is increased 75% by treatment with 100 pM 17beta-estradiol; this response is blocked by both progesterone and tamoxifen. These results show that neuronal sprouting is increased by estrogen in the same region where sprouting is dependent on apolipoprotein E. Sprouting may be stimulated by estrogen through its up-regulation of apolipoprotein E expression leading to increased recycling of membrane lipids for use by sprouting neurons. Estrogen and apolipoprotein E may therefore interact in their modulation of both Alzheimer's disease risk and recovery from CNS injury.

We tested the neuroprotective potential of the Bcl-2(20-34) peptide sequence in hippocampal slices. Treatment with Bcl-2 after fluid percussion trauma significantly improved recovery of CA1 antidromic PS to a mean of 92%+/-1 of initial amplitude, compared with only 16%+/-2 in unmedicated slices. The EC50 for trauma protection was 84 microM Bcl-2(20-34). Protection with Bcl-2(20-34) also extended to long-term potentiation. No protection was seen with the reverse sequence of Bcl-2(20-34). Treatment with Bcl-2(20-34) also protected against hypoxic damage, with treated slices recovering to 98%+/-2, while unmedicated slices recovered to 14%+/-2. Similar protection was seen against AMPA, NMDA and nitric oxide. These findings indicate that Bcl-2(20-34) provides specific neuroprotection against acute CA1 neuronal injury.

The transforming growth factor-beta (TGF-beta) family consists of three isoforms and is part of a larger family of cytokines regulating differentiation, development, and tissue repair. Previous work from our laboratory has shown that TGF-beta1 can increase amyloid-beta protein (Abeta) immunoreactive (Abetair) plaque-like deposits in rat brain. The aim of the current study was to evaluate all three isoforms of TGF-beta for their ability to affect the deposition and neurotoxicity of Abeta in an organotypic, hippocampal slice culture model of Abeta deposition. Slice cultures were treated with Abeta either with or without one of the TGF-beta isoforms. All three isoforms can increase Abeta accumulation (over Abeta treatment alone) within the slice culture, as determined by ELISA. However, there are striking differences in the pattern of Abetair among the three isoforms of TGF-beta. Isoforms 1 and 3 produced a cellular pattern of Abeta staining that colocalizes with GS lectin staining (microglia). TGF-beta2 produces dramatic Abeta staining of pyramidal neurons in layers CA1-CA2. In addition to cellular Abeta staining, plaque-like deposits are increased by all of the TGF-betas. Although no gross toxicity was observed, morphological neurodegenerative changes were seen in the CA1 region when the slices were treated with Abeta plus TGF-beta2. Our results demonstrate important functional differences among the TGF-beta isoforms in their ability to alter the cellular distribution and degradation of Abeta. These changes may be relevant to the pathology of Alzheimer's disease (AD).