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Introduction Immunotherapeutic approaches targeting amyloid β (Aβ) protein and tau in Alzheimer's disease and α-synuclein (α-syn) in Parkinson's disease are being developed for treating dementia with Lewy bodies. However, it is unknown if single or combined immunotherapies targeting Aβ and/or α-syn may be effective. Methods Amyloid precursor protein/α-syn tg mice were immunized with AFFITOPEs® (AFF) peptides specific to Aβ (AD02) or α-syn (PD-AFF1) and the combination. Results AD02 more effectively reduced Aβ and pTau burden; however, the combination exhibited some additive effects. Both AD02 and PD-AFF1 effectively reduced α-syn, ameliorated degeneration of pyramidal neurons, and reduced neuroinflammation. PD-AFF1 more effectively ameliorated cholinergic and dopaminergic fiber loss; the combined immunization displayed additive effects. AD02 more effectively improved buried pellet test behavior, whereas PD-AFF1 more effectively improved horizontal beam test; the combined immunization displayed additive effects. Discussion Specific active immunotherapy targeting Aβ and/or α-syn may be of potential interest for the treatment of dementia with Lewy bodies.

Vaccination is increasingly being investigated as a potential treatment for synucleinopathies, a group of neurodegenerative diseases including Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies associated with α-synuclein pathology. All lack a causal therapy. Development of novel, disease-altering treatment strategies is urgently needed. Vaccination has positioned itself as a prime strategy for addressing these diseases because it is broadly applicable, requires infrequent administration, and maintains low production costs for treating a large population or as a preventive measure. Current evidence points to a causal role of misfolded α-synuclein in the development and progression of synucleinopathies. In the past decade, significant progress in active immunization against α-synuclein has been shown both in preclinical animal models and in early clinical development. In this review, we describe the state-of-the-art in active immunization approaches to synucleinopathies, with a focus on advances in Parkinson's disease (PD) and multiple-system atrophy (MSA). We first review preclinical animal models, highlighting their progress in translation to the clinical setting. We then discuss current clinical applications, stressing different approaches taken to address α-synuclein pathology. Finally, we address challenges, trends, and future perspectives of current vaccination programs.

Immunotherapeutic approaches are currently in the spotlight for their potential as disease-modifying treatments for neurodegenerative disorders. The discovery that α-synuclein (α-syn) can transmit from cell to cell in a prion-like fashion suggests that immunization might be a viable option for the treatment of synucleinopathies. This possibility has been bolstered by the development of next-generation active vaccination technology with short peptides-AFFITOPEs(®) (AFF)- that do not elicit an α-syn-specific T cell response. This approach allows for the production of long term, sustained, more specific, non-cross reacting antibodies suitable for the treatment of synucleinopathies, such as Parkinson's disease (PD). In this context, we screened a large library of peptides that mimic the C-terminus region of α-syn and discovered a novel set of AFF that identified α-syn oligomers. Next, the peptide that elicited the most specific response against α-syn (AFF 1) was selected for immunizing two different transgenic (tg) mouse models of PD and Dementia with Lewy bodies, the PDGF- and the mThy1-α-syn tg mice. Vaccination with AFF 1 resulted in high antibody titers in CSF and plasma, which crossed into the CNS and recognized α-syn aggregates. Active vaccination with AFF 1 resulted in decreased accumulation of α-syn oligomers in axons and synapses, accompanied by reduced degeneration of TH fibers in the caudo-putamen nucleus and by improvements in motor and memory deficits in both in vivo models. Clearance of α-syn involved activation of microglia and increased anti-inflammatory cytokine expression, further supporting the efficacy of this novel active vaccination approach for synucleinopathies.

We evaluated the usefulness of small animal brain positron emission tomography (PET) imaging with the amyloid-beta (A beta) probe 2-(1-{6-[(2-[(18)F]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malonitrile ([(18)F]FDDNP) and with 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) for detection and quantification of pathological changes occurring in a transgenic mouse model of Alzheimer's disease (Tg2576 mice).[(18)F]FDDNP (n = 6) and FDG-PET scans (n = 3) were recorded in Tg2576 mice (age 13-15 months) and age-matched wild-type litter mates. Brain volumes of interest were defined by co-registration of PET images with a 3D MOBY digital mouse phantom. Regional [(18)F]FDDNP retention in mouse brain was quantified in terms of the relative distribution volume (DVR) using Logan's graphical analysis with cerebellum as a reference region.Except for a lower maximum brain uptake of radioactivity in transgenic animals, the regional brain kinetics as well as DVR values of [(18)F]FDDNP appeared to be similar in both groups of animals. Also for FDG, regional radioactivity retention was almost identical in the brains of transgenic and control animals.We could not detect regionally increased [(18)F]FDDNP binding and regionally decreased FDG binding in the brains of Tg2576 transgenic versus wild-type mice. However, small group differences in signal might have been masked by inter-animal variability. In addition, technical limitations of the applied method (partial volume effect, spatial resolution) for measurements in such small organs as mouse brain have to be taken into consideration.

Background Alzheimer’s disease (AD) is the most common neurodegenerative disease characterized by neuronal loss due to amyloid beta aggregations, neurofibrillary tangles, and prominent neuroinflammation. Recently, interference with neuroinflammation as a new therapeutic approach for AD treatment gained great interest. Microglia cells, one of the major contributors in neuroinflammation, are activated in response to misfolded proteins such as amyloid β and cell debris leading to a sustained release of pro-inflammatory mediators. Especially, complement factor C5a and its receptor have been found to be up-regulated in microglia in the immediate surroundings of cerebral amyloid plaques and blocking of C5aR resulted in a reduction of pathological markers in a model of AD. Here, we investigate the effect of active vaccination against the complement factor C5a to interfere with neuroinflammation and neuropathologic alterations in a mouse model of AD. Methods Short antigenic peptides AFF1 and AFF2, which mimic a C-terminal epitope of C5a, were selected and formulated to vaccines. These vaccines are able to induce a highly specific antibody response to the target protein C5a. Tg2576 mice, a common model of AD, were immunized with these two C5a-peptide vaccines and the induced immune response toward C5a was analyzed by ELISA and Western blot analysis. The influence on memory retention was assessed by a contextual fear conditioning test. Microglia activation and amyloid plaque deposition in the brain was visualized by immunohistochemistry. Results Both C5a-targeting vaccines were highly immunogenic and induced sustained antibody titers against C5a. Tg2576 mice vaccinated at early stages of the disease showed significantly improved contextual memory accompanied by the reduction of microglia activation in the hippocampus and cerebral amyloid plaque load compared to control mice. Late-stage immunization also showed a decrease in the number of activated microglia, and improved memory function, however, had no influence on the amyloid β load. Conclusion C5a-peptide vaccines represent a safe and well-tolerated immunotherapy, which is able to induce a strong and specific immune response against the pro-inflammatory molecule C5a. In a mouse model of AD, C5a-peptide vaccines reduce microglia activation and thus neuroinflammation, which is supposed to lead to reduced neuronal dysfunction and AD symptomatic decline.

Vaccination is increasingly being investigated as a potential treatment for synucleinopathies, a group of neurodegenerative diseases including Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies associated with α-synuclein pathology. All lack a causal therapy. Development of novel, disease-altering treatment strategies is urgently needed. Vaccination has positioned itself as a prime strategy for addressing these diseases because it is broadly applicable, requires infrequent administration, and maintains low production costs for treating a large population or as a preventive measure. Current evidence points to a causal role of misfolded α-synuclein in the development and progression of synucleinopathies. In the past decade, significant progress in active immunization against α-synuclein has been shown both in preclinical animal models and in early clinical development. In this review, we describe the state-of-the-art in active immunization approaches to synucleinopathies, with a focus on advances in Parkinson's disease (PD) and multiple-system atrophy (MSA). We first review preclinical animal models, highlighting their progress in translation to the clinical setting. We then discuss current clinical applications, stressing different approaches taken to address α-synuclein pathology. Finally, we address challenges, trends, and future perspectives of current vaccination programs.

Morphogenesis of hairs and feathers is initiated by an as yet unknown dermal signal that induces placode formation in the overlying ectoderm. To determine whether FGF signals are required for this process we over-expressed soluble versions of FGFR1 or FGFR2 in the skin of chicken embryos. This produced a complete failure of feather formation prior to any morphological or molecular signs of placode development. We further show that Fgf10 is expressed in the dermis of nascent feather primordia, and that anti-FGF10 antibodies block feather placode development in skin explants. In addition we show that FGF10 can induce expression of positive and negative regulators of feather development and can induce its own expression under conditions of low BMP signaling. Together these results demonstrate that FGF signaling is required for the initiation of feather placode development and implicate FGF10 as an early dermal signal involved in this process.

Pyroglutamylated amyloid-β (pE(3)-Aβ) has been suggested to play a major role in Alzheimer’s disease (AD) pathogenesis as amyloid-β (Aβ) oligomers containing pE(3)-Aβ might initiate tau-dependent cytotoxicity. We aimed to further elucidate the associations among pE(3)-Aβ, full-length Aβ and hyperphosphorylated tau (HP-τ) in human brain tissue. We examined 41 post mortem brains of both AD (n = 18) and controls. Sections from frontal and entorhinal cortices were stained with pE(3)-Aβ, HP-τ and full-length Aβ antibodies. The respective loads were assessed using image analysis and western blot analysis was performed in a subset of cases. All loads were significantly higher in AD, but when using Aβ loads as independent variables only frontal pE(3)-Aβ load predicted AD. In frontal and entorhinal cortices pE(3)-Aβ load independently predicted HP-τ load while non-pE(3)-Aβ failed to do so. All loads correlated with the severity of AD neuropathology. However, partial correlation analysis revealed respective correlations in the frontal cortex only for pE(3)-Aβ load only while in the entorhinal cortex respective correlations were seen for both HP-τ and non-pE(3)-Aβ loads. Mini Mental State Examination scores were independently predicted by entorhinal HP-τ load and by frontal pE(3)-Aβ load. Here, we report an association between pE(3)-Aβ and HP-τ in human brain tissue and an influence of frontal pE(3)-Aβ on both the severity of AD neuropathology and clinical dementia. Our findings further support the notion that pE(3)-Aβ may represent an important link between Aβ and HP-τ, and investigations into its role as diagnostic and therapeutic target in AD are warranted.

Tooth development is initiated by signals from the oral ectoderm which induce gene expression required for tooth development in the underlying mesenchyme. In this study, we have used Su5402, an inhibitor of FGF receptor signaling, to analyze the requirement of FGF signaling during early tooth development. We show that FGF signaling is necessary for expression of Pax9, a transcription factor required for development of all teeth, in prospective incisor and molar mesenchyme until E11.0. Expression of the LIM homeobox gene Lhx7 also requires FGF signaling until E11.0 whereas expression of its homologue Lhx6 and the homeobox transcription factor Barx1 already becomes independent of FGF signaling at E10.75. In contrast, ectodermal expression of several genes thought to be important for tooth development was unaffected by the block of FGF signaling. Finally, we show that expression of the TGFβ antagonist Dan in prospective tooth mesenchyme requires ectodermal signals and can be induced by FGF-soaked beads but is maintained in mandibular explants in the absence of FGF signaling. Together, these results demonstrate that FGF signaling is required for development of both molar and incisor teeth and suggest that specification of tooth mesenchyme involves at least two FGF-dependent steps.

The neurodegenerative pathology in patients with Alzheimer’s disease (AD) has been associated with the progressive accumulation of aggregated and post-translationally modified amyloid-β (Aβ) species. Among them, recent studies indicate that the pyroglutamate modification of Aβ (pE(3)Aβ) catalyzed by glutaminyl cyclase might play an important role in the pathogenesis of AD. Although the effects of the pyroglutamate modification on Aβ aggregation and toxicity have been investigated, less is known about the distribution of pE(3)Aβ across the spectrum of AD and in the brains of amyloid-β protein precursor (AβPP) transgenic (tg) animals. For this purpose, we generated a novel monoclonal antibody (denominated D129) that specifically recognizes pE(3)Aβ and characterized the patterns of distribution in the postmortem brain samples from AD patients divided by disease stage (Braak stage) and in AβPP tg mice. We found that in early stages of AD and young AβPP tg mice pE(3)Aβ was found in discrete linear and granular aggregates in the neuropil that co-localized with the pre-synaptic protein synaptophysin and was in close opposition to dendrites labeled with MAP2. In later stages of AD and in older AβPP tg mice, pE(3)Aβ was abundant in diffuse and mature plaques. In conclusion, this study suggests that peri-synaptic accumulation of pE(3)Aβ might contribute to early cognitive dysfunction in AD.

Neurodegenerative diseases are still an area of unmet medical need. This is in contrast to our increasing knowledge on their pathology (e.g., Alzheimer's- (AD), Parkinson's (PD) disease). They are driven by the cerebral accumulation and aggregation of specific proteins (e.g., β-amyloid and hyperphosphorylated tau in the case of AD) in defined brain regions and, as a consequence, death of neurons. Accordingly, removal of given protein aggregates is expected to modify the course of the respective neurodegenerative disease. This has been convincingly demonstrated in animal models of human diseases. However, not every technology that can be used and proves successful in animal models can be translated to the human situation. As highlighted by recent progress in the field of AD research, specific immunotherapy is a viable option in this regard. Given the fact that the aggregates are composed of self-proteins, immunotherapeutic approaches have to consider the issue of potential autoimmunity. This is especially true in case of vaccines. An innovative solution to this problem is offered by the so called AFFITOME® technology, which relies on the use of "doubles" of native molecules, functionally mimotopes or AFFITOPES® if identified by AFFiRiS, as the antigenic vaccine component.

Recent evidence suggests Alzheimer-Disease (AD) to be driven by aggregated Aß. Capitalizing on the mechanism of molecular mimicry and applying several selection layers, we screened peptide libraries for moieties inducing antibodies selectively reacting with Aß-aggregates. The technology identified a pool of peptide candidates; two, AFFITOPES AD01 and AD02, were assessed as vaccination antigens and compared to Aβ1-6, the targeted epitope. When conjugated to Keyhole Limpet Hemocyanin (KLH) and adjuvanted with aluminum, all three peptides induced Aß-targeting antibodies (Abs). In contrast to Aß1-6, AD01- or AD02-induced Abs were characterized by selectivity for aggregated forms of Aß and absence of reactivity with related molecules such as Amyloid Precursor Protein (APP)/ secreted APP-alpha (sAPPa). Administration of AFFITOPE-vaccines to APP-transgenic mice was found to reduce their cerebral amyloid burden, the associated neuropathological alterations and to improve their cognitive functions. Thus, the AFFITOME-technology delivers vaccines capable of inducing a distinct Ab response. Their features may be beneficial to AD-patients, a hypothesis currently tested within a phase-II-study.

The mammalian kidney develops in three successive steps from the initial pronephros via the mesonephros to the adult metanephros. Although the nephric lineage is specified during pronephros induction, no single regulator, including the transcription factor Pax2 or Pax8, has yet been identified to control this initial phase of kidney development. In this paper, we demonstrate that mouse embryos lacking both Pax2 and Pax8 are unable to form the pronephros or any later nephric structures. In these double-mutant embryos, the intermediate mesoderm does not undergo the mesenchymal-epithelial transitions required for nephric duct formation, fails to initiate the kidney-specific expression of Lim1 and c-Ret, and is lost by apoptosis 1 d after failed pronephric induction. Conversely, retroviral misexpression of Pax2 was sufficient to induce ectopic nephric structures in the intermediate mesoderm and genital ridge of chick embryos. Together, these data identify Pax2 and Pax8 as critical regulators that specify the nephric lineage.

Background Multiple system atrophy (MSA) is a neurodegenerative disease characterized by parkinsonism, ataxia and dysautonomia. Histopathologically, the hallmark of MSA is the abnormal accumulation of alpha-synuclein (α-syn) within oligodendroglial cells, leading to neuroinflammation, demyelination and neuronal death. Currently, there is no disease-modifying treatment for MSA. In this sense, we have previously shown that next-generation active vaccination technology with short peptides, AFFITOPEs®, was effective in two transgenic models of synucleinopathies at reducing behavioral deficits, α-syn accumulation and inflammation. Results In this manuscript, we used the most effective AFFITOPE® (AFF 1) for immunizing MBP-α-syn transgenic mice, a model of MSA that expresses α-syn in oligodendrocytes. Vaccination with AFF 1 resulted in the production of specific anti-α-syn antibodies that crossed into the central nervous system and recognized α-syn aggregates within glial cells. Active vaccination with AFF 1 resulted in decreased accumulation of α-syn, reduced demyelination in neocortex, striatum and corpus callosum, and reduced neurodegeneration. Clearance of α-syn involved activation of microglia and reduced spreading of α-syn to astroglial cells. Conclusions This study further validates the efficacy of vaccination with AFFITOPEs® for ameliorating the neurodegenerative pathology in synucleinopathies. Electronic supplementary material The online version of this article (doi:10.1186/s13024-015-0008-9) contains supplementary material, which is available to authorized users.