In vivo studies have shown that blood-brain barrier (BBB) dysfunction is involved in the course of Parkinson's disease (PD). However, these have lacked either anatomic definition or the ability to recognize minute changes in BBB integrity. Here, using histologic markers of serum protein, iron, and erythrocyte extravasation, we have shown significantly increased permeability of the BBB in the postcommissural putamen of PD patients. The dense innervation of the striatum by PD-affected regions allows for exploitation of this permeability for therapeutic goals. These results are also discussed in the context of the retrograde transsynaptic hypothesis of PD spread. Keywords: α-synuclein; blood-brain barrier; Parkinson's disease; striatum INTRODUCTION Parkinson's disease (PD) is characterized by aggregation of filamentous or oligomerized α-synuclein and degeneration of specific neuronal regions. According to the dual-hit hypothesis of PD pathogenesis, a microbial or toxic pathogen within the gut lumen and the olfactory mucosa represents the pathogenic agent, with subsequent prion-like spread of pathology, first to the dorsal motor nucleus of the vagus and central olfactory areas, respectively, then to higher centers. The connectional anatomy linking the dorsal motor nucleus and olfactory bulb with higher centers such as the substantia nigra is unproven.We have previously proposed that disease could be spread hematogenously. 1 This is conceivable within the paradigm of retrograde (axon terminal to soma) Lewy pathology spread. 2,3 Almost all regions affected in Braak stage 1 have axon terminals outside the blood-brain barrier (BBB). That same BBB, however, protects the higher-order regions, whose axon terminals reside within the central nervous system, from blood-borne substances. Cell-to-cell spread is a potential mechanism to circumvent this protection but the connectional neuroanatomy is not consistent with the temporal order of Lewy pathology development as it is currently understood.Nigrostriatal dopaminergic neuronal cell bodies develop significant Lewy pathology, but recent studies strongly suggest that α-synuclein aggregation in these cells begins at presynaptic axon terminal in the striatum and spreads retrogradely to nigral

Parkinson's disease is characterized by the pathological aggregation of Alpha-synuclein. The dual-hit hypothesis proposed by Braak implicates the enteric nervous system as an initial site of α-synuclein aggregation with subsequent spread to the central nervous system. Regional variations in the spatial pattern or levels of α-synuclein along the enteric nervous system could have implications for identifying sites of onset of this pathogenic cascade. We performed immunohistochemical staining for α-synuclein on gastrointestinal tissue from patients with no history of neurological disease using the established LB509 antibody and a new clone, MJFR1, characterized for immunohistochemistry here. We demonstrate that the vermiform appendix is particularly enriched in α-synuclein-containing axonal varicosities, concentrated in its mucosal plexus rather than the classical submucosal and myenteric plexuses. Unexpectedly, intralysosomal accumulations of α-synuclein were detected within mucosal macrophages of the appendix. The abundance and accumulation of α-synuclein in the vermiform appendix implicate it as a candidate anatomical locus for the initiation of enteric α-synuclein aggregation and permits the generation of testable hypotheses for Parkinson's disease pathogenesis.

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UCHL1 (ubiquitin carboxyterminal hydrolase 1) is a deubiquitinating enzyme that is particularly abundant in neurons. From studies of a spontaneous mutation arising in a mouse line it is clear that loss of function of UCHL1 generates profound degenerative changes in the central nervous system, and it is likely that a proteolytic deficit contributes to the pathology. Here these effects were found to be recapitulated in mice in which the Uchl1 gene had been inactivated by homologous recombination. In addition to the previously documented neuropathology associated with loss of UCHL1 function, axonal swellings were detected in the striatum. In agreement with previously reported findings the loss of UCHL1 function was accompanied by perturbations in ubiquitin pools, but glutathione levels were also significantly depleted in the brains of the knockout mice, suggesting that oxidative defense mechanisms may be doubly compromised. To determine if, in addition to its role in the central nervous system, UCHL1 function is also required for homeostasis of the enteric nervous system the gastrointestinal tract was analyzed in UCHL1 knockout mice. The mice displayed functional changes and morphological changes in gut neurons that preceded degenerative changes in the brain. The changes were qualitatively and quantitatively similar to those observed in wild type mice of much greater age, and strongly resemble changes reported for elderly humans. UCHL1 knockout mice should therefore serve as a useful model of gut aging.

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Objectives:To identify the epitope on α-synuclein (α-syn) to which antibodies against the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) bind and to determine whether antibodies targeting this mimicry domain are present in human sera.Methods:Reactivity of the α-syn-cross-reacting anti-LMP1 monoclonal antibody CS1-4 to a synthetic peptide containing the putative mimicry domain was compared to those in which this domain was mutated and to murine and rat α-syn (which differ from human α-syn at this site) in Western blots. Using ELISA, sera from EBV+ (n = 4) and EBV− (n = 12) donors as well as those with infectious mononucleosis (IM; n = 120), and Hodgkin disease (HD; n = 33) were interrogated for antibody reactivity to synthetic peptides corresponding to regions of α-syn and LMP1 containing the mimicry domain.Results:CS1-4 showed strong reactivity to wild-type human α-syn, but not to the mutant peptides or rodent α-syn. Control EBV− and EBV+ sera showed no reactivity to α-syn or LMP1 peptides. However, a significant proportion of IM and HD sera contained immunoglobulin M (IgM) (59% and 70%, in IM and HD, respectively), immunoglobulin G (IgG) (40% and 48%), and immunoglobulin A (IgA) (28% and 36%) antibodies to both peptides, as well as a significant correlation in the titers of IgM (ρ = 0.606 and 0.664, for IM and HD, respectively), IgG (0.526 and 0.836), and IgA (0.569 and 0.728) antibodies targeting LMP1 and α-syn peptides.Conclusions:Anti-EBV-LMP1 antibodies cross-reacting with a defined epitope in α-syn are present in human patients. These findings may have implications for the pathogenesis of synucleinopathies.

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Background Chikungunya virus (CHIKV) is a mosquito-borne pathogen, within the Alphavirus genus of the Togaviridae family, that causes ~1.1 million human infections annually. CHIKV uses Aedes albopictus and Aedes aegypti mosquitoes as insect vectors. Human infections can develop arthralgia and myalgia, which results in debilitating pain for weeks, months, and even years after acute infection. No therapeutic treatments or vaccines currently exist for many alphaviruses, including CHIKV. Targeting the phagocytosis of CHIKV by macrophages after mosquito transmission plays an important role in early productive viral infection in humans, and could reduce viral replication and/or symptoms. Methods To better characterize the transcriptional response of macrophages during early infection, we generated RNA-sequencing data from a CHIKV-infected human macrophage cell line at eight or 24 hours post-infection (hpi), together with mock-infected controls. We then calculated differential gene expression, enriched functional annotations, modulated intracellular signaling pathways, and predicted therapeutic drugs from these sequencing data. Results We observed 234 pathways were significantly affected 24 hpi, resulting in six potential pharmaceutical treatments to modulate the affected pathways. A subset of significant pathways at 24 hpi includes AGE-RAGE, Fc epsilon RI, Chronic myeloid leukemia, Fc gamma R-mediated phagocytosis, and Ras signaling. We found that the MAPK1 and MAPK3 proteins are shared among this subset of pathways and that Telmisartan and Dasatinib are strong candidates for repurposed small molecule therapeutics that target human processes. The results of our analysis can be further characterized in the wet lab to contribute to the development of host-based prophylactics and therapeutics.