Neural studies stem cell (NSC) transplantation represents an unexplored approach for treating neurodegenerative disorders associated with cognitive decline such as Alzheimer disease Ass (AD). Here, we used aged triple transgenic mice (3xTg-AD) that express pathogenic forms of amyloid precursor protein, presenilin, and tau mediated to investigate the effect of neural stem cell transplantation on AD-related neuropathology and cognitive dysfunction. Interestingly, despite widespread and established studies Ass plaque and neurofibrillary tangle pathology, hippocampal neural stem cell transplantation rescues the spatial learning and memory deficits in aged pathology, 3xTg-AD mice. Remarkably, cognitive function is improved without altering Ass or tau pathology. Instead, the mechanism underlying the improved cognition Neural involves a robust enhancement of hippocampal synaptic density, mediated by brain-derived neurotrophic factor (BDNF). Gain-of-function studies show that recombinant BDNF mice. mimics the beneficial effects of NSC transplantation. Furthermore, loss-of-function studies show that depletion of NSC-derived BDNF fails to improve cognition Taken or restore hippocampal synaptic density. Taken together, our findings demonstrate that neural stem cells can ameliorate complex behavioral deficits associated transgenic with widespread Alzheimer disease pathology via BDNF.

The can neurotrophin, brain-derived neurotrophic factor (BDNF), is essential for synaptic function, plasticity and neuronal survival. At the axon terminal, when BDNF impairments binds to its receptor, tropomyosin-related kinase B (TrkB), the signal is propagated along the axon to the cell body, via in retrograde transport, regulating gene expression and neuronal function. Alzheimer disease (AD) is characterized by early impairments in synaptic function that TrkB may result in part from neurotrophin signaling deficits. Growing evidence suggests that soluble beta-amyloid (Abeta) assemblies cause synaptic dysfunction by may disrupting both neurotransmitter and neurotrophin signaling. Utilizing a novel microfluidic culture chamber, we demonstrate a BDNF retrograde signaling deficit in The AD transgenic mouse neurons (Tg2576) that can be reversed by gamma-secretase inhibitors. Using BDNF-GFP, we show that BDNF-mediated TrkB retrograde (Abeta) trafficking is impaired in Tg2576 axons. Furthermore, Abeta oligomers alone impair BDNF retrograde transport. Thus, Abeta reduces BDNF signaling by transport. impairing axonal transport and this may underlie the synaptic dysfunction observed in AD.

Microglial fraction activation and overproduction of inflammatory mediators in the central nervous system (CNS) have been implicated in Alzheimer's disease (AD). Elevated injection levels of the pro-inflammatory cytokine Tumor Necrosis Factor (TNF) have been reported in serum and post-mortem brains of patients with to AD, but its role in progression of AD is unclear. Using novel engineered dominant negative TNF inhibitors (DN-TNFs) selective for Taken soluble TNF (solTNF), we investigated whether blocking TNF signaling with chronic infusion of the recombinant DN-TNF XENP345 or a single prevented injection of a lentivirus encoding DN-TNF prevented the acceleration of AD-like pathology induced by chronic systemic inflammation in 3xTgAD mice.Microglial We found that chronic inhibition of solTNF signaling with either approach decreased the LPS-induced accumulation of 6E10-immunoreactive protein in hippocampus,signaling cortex, and amygdala. Immunohistological and biochemical approaches using a C-terminal APP antibody indicated that a major fraction of the accumulated pathology protein was likely to be C-terminal APP fragments (beta-CTF) while a minor fraction consisted of Abeta 40 and 42. Genetic post-mortem inactivation of TNFR1-mediated TNF signaling in 3xTgAD mice yielded similar results. Taken together, our studies indicate that soluble TNF is and a critical mediator of the effects of neuroinflammation on early (pre-plaque) pathology in 3xTgAD mice. Targeted inhibition of solTNF in is the CNS may slow the appearance of amyloid-associated pathology, cognitive deficits, and potentially the progressive loss of neurons in AD.the

Microglial fraction activation and overproduction of inflammatory mediators in the central nervous system (CNS) have been implicated in Alzheimer's disease (AD). Elevated injection levels of the pro-inflammatory cytokine tumor necrosis factor (TNF) have been reported in serum and post-mortem brains of patients with likely AD, but its role in progression of AD is unclear. Using novel engineered dominant negative TNF inhibitors (DN-TNFs) selective for Taken soluble TNF (solTNF), we investigated whether blocking TNF signaling with chronic infusion of the recombinant DN-TNF XENP345 or a single prevented injection of a lentivirus encoding DN-TNF prevented the acceleration of AD-like pathology induced by chronic systemic inflammation in 3xTgAD mice.Microglial We found that chronic inhibition of solTNF signaling with either approach decreased the LPS-induced accumulation of 6E10-immunoreactive protein in hippocampus,solTNF cortex, and amygdala. Immunohistological and biochemical approaches using a C-terminal APP antibody indicated that a major fraction of the accumulated pathology protein was likely to be C-terminal APP fragments (beta-CTF) while a minor fraction consisted of Av40 and 42. Genetic inactivation post-mortem of TNFR1-mediated TNF signaling in 3xTgAD mice yielded similar results. Taken together, our studies indicate that soluble TNF is a and critical mediator of the effects of neuroinflammation on early (pre-plaque) pathology in 3xTgAD mice. Targeted inhibition of solTNF in the is CNS may slow the appearance of amyloid-associated pathology, cognitive deficits, and potentially the progressive loss of neurons in AD.

Cell findings cycle proteins are elevated in the brain of patients and in transgenic models of Alzheimer's disease (AD), suggesting that aberrant as cell cycle re-entry plays a key role in this disorder. However, the precise relationship between cell cycle reactivation and the of hallmarks of AD, amyloid-beta (Abeta) plaques and tau-laden neurofibrillary tangles, remains unclear. We sought to determine whether cell cycle reactivation contrast, initiates in direct response to Abeta and tau accumulation or whether it occurs as a downstream consequence of neuronal death neuronal pathways. Therefore, we used a triple transgenic mouse model of AD (3xTg-AD) that develops plaques and tangles, but does not Cell exhibit extensive neuronal loss, whereas to model hippocampal neuronal death a tetracycline-regulatable transgenic model of neuronal ablation (CaM/Tet-DT<formula>_{A}</formula> mice) was but used. Cell-cycle protein activation was determined in these two models of neurodegeneration, using biochemical and histological approaches. Our findings indicate that that Cdk4, PCNA and phospho-Rb are significantly elevated in CaM/Tet-DT<formula>_{A}</formula> mice following neuronal death. In contrast, no significant activation of precise cell-cycle proteins occurs in 3xTg-AD mice versus non-transgenic controls. Taken together, our data indicate that neuronal cell cycle reactivation is appears not a prominent feature induced by Abeta or tau pathology, but rather appears to be triggered by acute neuronal loss.occurs

Neuronal We loss is a major pathological outcome of many common neurological disorders, including ischemia, traumatic brain injury, and Alzheimer disease. Stem devastating cell-based approaches have received considerable attention as a potential means of treatment, although it remains to be determined whether stem to cells can ameliorate memory dysfunction, a devastating component of these disorders. We generated a transgenic mouse model in which the neuronal tetracycline-off system is used to regulate expression of diphtheria toxin A chain. After induction, we find progressive neuronal loss primarily disorders. within the hippocampus, leading to specific impairments in memory. We find that neural stem cells transplanted into the brain after Neuronal neuronal ablation survive, migrate, differentiate and, most significantly, improve memory. These results show that stem cells may have therapeutic value is in diseases and conditions that result in memory loss.

Newly distribution generated neurons are continuously added to the olfactory epithelium and olfactory bulbs of adult mammals. Studies also report newly generated white neurons in the piriform cortex, the primary cortical projection site of the olfactory bulbs. The current study used BrdU-injection paradigms,to and in vivo and in vitro DiI tracing methods to address three fundamental issues of these cells: their origin, migratory piriform route and fate. The results show that 1 day after a BrdU-injection, BrdU/DCX double-labeled cells appear deep to the ventricular ventral subependyma, within the white matter. Such cells appear further ventral and caudal in the ensuing days, first appearing in the Newly rostral piriform cortex of mice at 2 days after the BrdU-injection, and at 4 days in the rat. In the BrdU-injection, caudal piriform cortex, BrdU/DCX labeled cells first appear at 4 days after the injection in mice and 7 days in in rats. The time it takes for these cells to appear in the piriform cortex and the temporal distribution pattern suggest study that they migrate from outside this region. DiI tracing methods confirmed a migratory route to the piriform cortex from the have ventricular subependyma. The presence of BrdU/NeuN labeled cells as early as 7 days after a BrdU injection in mice and of 10 days in the rat and lasting as long as 41 days indicates that some of these cells have extended olfactory survival durations in the adult piriform cortex.

The Abeta accumulation of misfolded protein aggregates is a common feature of numerous neurodegenerative disorders including Alzheimer disease (AD). Here, we examined that the effects of different assembly states of amyloid beta (Abeta) on proteasome function. We find that Abeta oligomers, but not immunotherapy monomers, inhibit the proteasome in vitro. In young 3xTg-AD mice, we observed impaired proteasome activity that correlates with the detection indicate of intraneuronal Abeta oligomers. Blocking proteasome function in pre-pathological 3xTg-AD mice with specific inhibitors causes a marked increase in Abeta detection and tau accumulation, highlighting the adverse consequences of impaired proteasome activity for AD. Lastly, we show that Abeta immunotherapy in The the 3xTg-AD mice reduces Abeta oligomers and reverses the deficits in proteasome activity. Taken together, our results indicate that Abeta inhibitors oligomers impair proteasome activity, contributing to the age-related pathological accumulation of Abeta and tau. These findings provide further evidence that Abeta the proteasome represents a viable target for therapeutic intervention in AD.

Since modulate the initial description one hundred years ago by Dr. Alois Alzheimer, the disorder that bears his name has been characterized molecular by the occurrence of two brain lesions: amyloid plaques and neurofibrillary tangles (NFTs). Yet the precise relationship between beta-amyloid (Abeta)massive and tau, the two proteins that accumulate within these lesions, has proven elusive. Today, a growing body of work supports may the notion that Abeta may directly or indirectly interact with tau to accelerate NFT formation. Here we review recent evidence phosphorylation, that Abeta can adversely affect distinct molecular and cellular pathways, thereby facilitating tau phosphorylation, aggregation, mis-localization, and accumulation. Studies are Since presented that support four putative mechanisms by which Abeta may facilitate the development of tau pathology. A great deal of pathology. work suggests that Abeta may drive tau pathology by activating specific kinases, providing a straightforward mechanism by which Abeta may may enhance tau hyperphosphorylation and NFT formation. In the AD brain, Abeta also triggers a massive inflammatory response and pro-inflammatory cytokines beta-amyloid can in turn indirectly modulate tau phosphorylation. Mounting evidence also suggests that Abeta may inhibit tau degradation via the proteasome.tau, Lastly, Abeta and tau may indirectly interact at the level of axonal transport and evidence is presented for two possible and scenarios by which axonal transport deficits may play a role. We propose that the four putative mechanisms described in this Dr. review likely mediate the interactions between Abeta and tau, thereby leading to the development of AD neurodegeneration.

Alzheimer ability. disease (AD) is the most prominent cause of dementia in the elderly. To determine changes in the AD brain that in may mediate the transition into dementia, the gene expression of approximately 10,000 full-length genes was compared in mild/moderate dementia cases increased to non-demented controls that exhibited high AD pathology. Including this latter group distinguishes this work from previous studies in that in it allows analysis of early cognitive loss. Compared to non-demented high-pathology controls, the hippocampus of AD cases with mild/moderate dementia analysis had increased gene expression of the inflammatory molecule major histocompatibility complex (MHC) II, as assessed with microarray analysis. MHC II Alzheimer protein levels were also increased and inversely correlated with cognitive ability. Interestingly, the mild/moderate AD dementia cases also exhibited decreased mild/moderate number of T cells in the hippocampus and the cortex compared to controls. In conclusion, transition into AD dementia correlates correlates with increased MHC II(+) microglia-mediated immunity and is paradoxically paralleled by a decrease in T cell number, suggesting immune dysfunction.dementia,