FoxO1 Alleviates the Mitochondrial ROS Levels Induced by α-Synuclein Preformed Fibrils in BV-2 Microglial Cells.

Parkinson's disease (PD) is a complex neurodegenerative disorder marked by the gradual deterioration of dopaminergic neurons, especially in the substantia nigra pars compacta (SNc). Dysregulation of the transcription factor FoxO1 is associated with various neurodegenerative conditions, including Alzheimer's disease and PD, though the specific mechanisms involved are not fully understood. This study explores the effects of α-Synuclein preformed fibrils (PFF) on BV-2 microglial cells, focusing on changes in molecular characteristics and their impact on neuronal degeneration. Our results demonstrate that PFF treatment significantly increases FoxO1 mRNA (p = 0.0443) and protein (p = 0.0216) levels, leading to its nuclear translocation (p = 0.0142) and enhanced expression of genes involved in the detoxification of reactive oxygen species (ROS), such as Catalase (Cat, p = 0.0249) and superoxide dismutase 2 (Sod2, p = 0.0313). Furthermore, we observed that PFF treatment elevates mitochondrial ROS levels. However, cells lacking FoxO1 or treated with FoxO1 inhibitors showed increased vulnerability to PFF-induced ROS, attributed to reduced expression of ROS detoxifying enzymes Cat and Sod2 (p < 0.0001). Besides enhancing ROS production, inhibiting FoxO1 also heightens neurotoxicity induced by PFF treatment in microglia-conditioned medium (p < 0.0001). Conversely, treatment with N-acetylcysteine or bacterial superoxide dismutase A mitigated the ROS increase induced by PFF (p < 0.0001). These findings suggest the essential role of FoxO1 in regulating ROS levels, which helps alleviate pathology in PFF-induced PD models. Our study provides insights into the genetic mechanisms of PD and suggests potential pathways for developing novel therapeutic strategies.

Gba1 E326K renders motor and non-motor symptoms with pathologic α-syn, tau and glial activation.

Mutations in the GBA1 gene are common genetic risk factors for Parkinson's disease (PD), disrupting enzymatic activity and causing lysosomal dysfunction, leading to elevated α-synuclein (α-syn) levels. While GBA1's role in synucleinopathy is well-established, recent research underscores neuroinflammation as a significant pathogenic mechanism in GBA1 deficiency. This study investigates neuroinflammation in Gba1 E326K knock-in mice, a model associated with increased PD and dementia risk. At 9 and 24 months, we assessed GBA1 protein and activity, α-synuclein pathology, neurodegeneration, motor deficits, and gliosis in the ventral midbrain and hippocampus using immunohistochemistry (IHC), Western blot (WB), and GCase assays. Additionally, primary microglia from WT and GBA1E326K/E326K mice were treated with α-syn preformed fibrils (PFF) to study microglia activation, pro-inflammatory cytokines, reactive astrocyte formation, and neuronal death through qPCR, WB, and immunocytochemistry analyses. We also evaluated the effects of gut inoculation of α-syn PFF in Gba1 E326K mice at 7 months and striatal inoculation at 10 months, assessing motor/non-motor symptoms, α-syn pathology, neuroinflammation, gliosis, and neurodegeneration via behavioural tests, IHC, and WB assays. At 24 months, Gba1 E326K knock-in mice showed reduced GCase enzymatic activity and glucosylceramide build-up in the ventral midbrain and hippocampus. Increased pro-inflammatory cytokines and reactive astrocytes were observed in microglia and astrocytes from Gba1 E326K mice treated with pathologic α-syn PFF. Gut inoculation of α-syn PFF increased Lewy body accumulation in the hippocampal dentate gyrus, with heightened microglia and astrocyte activation and worsened non-motor symptoms. Intrastriatal α-syn preformed fibril injection induced motor deficits, reactive glial protein accumulation, and tauopathy in the prefrontal cortex and hippocampus of Gba1 E326K mice. GBA1 deficiency due to the Gba1 E326K mutation exacerbates neuroinflammation and promotes pathogenic α-synuclein transmission, intensifying disease pathology in PD models. This study enhances our understanding of how the Gba1 E326K mutation contributes to neuroinflammation and the spread of pathogenic α-syn in the brain, suggesting new therapeutic strategies for PD and related synucleinopathies.

Transcellular transmission and molecular heterogeneity of aggregation-prone proteins in neurodegenerative diseases.

The accumulation of aggregation-prone proteins in a specific neuronal population is a common feature of neurodegenerative diseases, which is correlated with the development of pathological lesions in diseased brains. The formation and progression of pathological protein aggregates in susceptible neurons induce cellular dysfunction, resulting in progressive degeneration. Moreover, recent evidence supports the notion that the cell-to-cell transmission of pathological protein aggregates may be involved in the onset and progression of many neurodegenerative diseases. Indeed, several studies have identified different pathological aggregate strains. Although how these different aggregate strains form remains unclear, a variety of biomolecular compositions or cross-seeding events promoted by the presence of other protein aggregates in the cellular environment may affect the formation of different strains of pathological aggregates, which in turn can influence complex pathologies in diseased brains. In this review, we summarize the recent results regarding cell-to-cell transmission and the molecular heterogeneity of pathological aggregate strains, raising key questions for future research directions.

Employment of diverse in vitro systems for analyzing multiple aspects of disease, hereditary hemorrhagic telangiectasia (HHT).

BACKGROUND: In vitro disease modeling enables translational research by providing insight into disease pathophysiology and molecular mechanisms, leading to the development of novel therapeutics. Nevertheless, in vitro systems have limitations for recapitulating the complexity of tissues, and a single model system is insufficient to gain a comprehensive understanding of a disease. RESULTS: Here we explored the potential of using several models in combination to provide mechanistic insight into hereditary hemorrhagic telangiectasia (HHT), a genetic vascular disorder. Genome editing was performed to establish hPSCs (H9) with ENG haploinsufficiency and several in vitro models were used to recapitulate the functional aspects of the cells that constitute blood vessels. In a 2D culture system, endothelial cells showed early senescence, reduced viability, and heightened susceptibility to apoptotic insults, and smooth muscle cells (SMCs) exhibited similar behavior to their wild-type counterparts. Features of HHT were evident in 3D blood-vessel organoid systems, including thickening of capillary structures, decreased interaction between ECs and surrounding SMCs, and reduced cell viability. Features of ENG haploinsufficiency were observed in arterial and venous EC subtypes, with arterial ECs showing significant impairments. Molecular biological approaches confirmed the significant downregulation of Notch signaling in HHT-ECs. CONCLUSIONS: Overall, we demonstrated refined research strategies to enhance our comprehension of HHT, providing valuable insights for pathogenic analysis and the exploration of innovative therapeutic interventions. Additionally, these results underscore the importance of employing diverse in vitro systems to assess multiple aspects of disease, which is challenging using a single in vitro system.

Aplp1 interacts with Lag3 to facilitate transmission of pathologic α-synuclein.

Pathologic α-synuclein (α-syn) spreads from cell-to-cell, in part, through binding to the lymphocyte-activation gene 3 (Lag3). Here we report that amyloid ß precursor-like protein 1 (Aplp1) interacts with Lag3 that facilitates the binding, internalization, transmission, and toxicity of pathologic α-syn. Deletion of both Aplp1 and Lag3 eliminates the loss of dopaminergic neurons and the accompanying behavioral deficits induced by α-syn preformed fibrils (PFF). Anti-Lag3 prevents the internalization of α-syn PFF by disrupting the interaction of Aplp1 and Lag3, and blocks the neurodegeneration induced by α-syn PFF in vivo. The identification of Aplp1 and the interplay with Lag3 for α-syn PFF induced pathology deepens our insight about molecular mechanisms of cell-to-cell transmission of pathologic α-syn and provides additional targets for therapeutic strategies aimed at preventing neurodegeneration in Parkinson's disease and related α-synucleinopathies.

DJ-1 protects cell death from a mitochondrial oxidative stress due to GBA1 deficiency.

BACKGROUND: GBA1 mutations are the most common genetic risk factor for development of Parkinson's disease (PD). The loss of catalytic activity in GBA1, as well as the reduction of the GBA1 protein in certain cellular compartment, may increase disease progression. However, the mechanisms underlying cellular dysfunction caused by GBA1 deficiency are still mostly unknown. OBJECTIVE: In this study, we focus on the genetic interaction between GBA1 deficiency and PD-causing genes, such as DJ-1, in mitochondrial dysfunction. METHODS: GBA1 knockout (KO) SH-SY5Y cells were used to assess DJ-1 functions against oxidative stress in vitro. The levels of cellular reactive oxygen species were monitored with MitoSOX reagent. The expression of the PARK7 gene was analyzed using the quantitative real-time PCR (qRT-PCR). To understand the mechanism underlying DJ-1 upregulation in GBA1 KO cells, we assess ROS levels, antioxidant protein, and cell viability in GBA1 KO cells with treatment of ROS inhibitor N-acetyl-cysteine or miglustat, which is an inhibitor of glucosylceramide synthase. Dopaminergic degeneration was assessed from Gba1 L444P heterozygous mice mated with Park7 knockout mice. RESULTS: We find that DJ-1 is significantly upregulated in GBA1 KO cells. Elevated levels of DJ-1 are attributed to the transcriptional expression of PARK7 mRNA, but not the inhibition of DJ-1 protein degradation. Because DJ-1 expression is highly linked to oxidative stress, we observe cellular reactive oxygen species (ROS) in GBA1 KO cells. Moreover, several antioxidant gene expressions and protein levels are increased in GBA1 KO cells. To this end, GBA1 KO cells are more susceptible to H2O2-induced cell death. Importantly, there is a significant reduction in dopaminergic neurons in the midbrain from Gba1 L444P heterozygous mice mated with Park7 knockout mice, followed by mild motor dysfunction. CONCLUSION: Taken together, our results suggest that DJ-1 upregulation due to GBA1 deficiency has a protective role against oxidative stress. It may be supposed that mutations or malfunctions in the DJ-1 protein may have disadvantages in the survival of dopaminergic neurons in the brains of patients harboring GBA1 mutations.

The effect of prescription drug insurance on the incidence of potentially inappropriate prescribing: Evidence from Medicare Part D.

The Medicare Part D program has been documented to increase the affordability and accessibility of drugs and improve the quality of prescription drug use; however, less is known about the equity impact of the Part D program on potentially inappropriate prescribing-specifically, incidences of polypharmacy and potentially inappropriate medication (PIM) use based on different racial/ethnic groups. Using a difference in the regression discontinuity design, we found that among Whites, Part D was associated with increases in polypharmacy and "broadly defined" PIM use, while the use of "always avoid" PIM remained unchanged. Conversely, Blacks and Hispanics reported no changes in such drug utilization patterns.

Linking Gba1 E326K mutation to microglia activation and mild age-dependent dopaminergic Neurodegeneration.

Mutations in the GBA1 gene have been identified as a prevalent genetic risk factor for Parkinson's disease (PD). GBA1 mutations impair enzymatic activity, leading to lysosomal dysfunction and elevated levels of α-synuclein (α-syn). While most research has primarily focused on GBA1's role in promoting synucleinopathy, emerging evidence suggests that neuroinflammation may be a key pathogenic alteration caused by GBA1 deficiency. To examine the molecular mechanism underlying GBA1 deficiency-mediated neuroinflammation, we generated Gba1 E326K knock-in (KI) mice using the CRISPR/Cas9 technology, which is linked to an increased risk of PD and dementia with Lewy bodies (DLB). In the ventral midbrain and hippocampus of 24-month-old Gba1 E326K KI mice, we found a moderate decline in GBA1 enzymatic activity, a buildup of glucosylceramide, and an increase in microglia density. Furthermore, we observed increased levels of pro-inflammatory cytokines and formation of reactive astrocytes in primary microglia and astrocytes, respectively, cultured from Gba1 E326K KI mice following treatment with pathologic α-syn preformed fibrils (PFF). Additionally, the gut inoculation of α-syn PFF in Gba1 E326K KI mice significantly enhanced the accumulation of Lewy bodies in the dentate gyrus of the hippocampus, accompanied by aggravated neuroinflammation and exacerbated non-motor symptoms. This research significantly enhances our understanding of the Gba1 E326K mutation's involvement in neuroinflammation and the cell-to-cell transmission of pathogenic α-syn in the brain, thereby opening new therapeutic avenues.

RepID represses megakaryocytic differentiation by recruiting CRL4A-JARID1A at DAB2 promoter.

BACKGROUND: Megakaryocytes (MKs) are platelet precursors, which arise from hematopoietic stem cells (HSCs). While MK lineage commitment and differentiation are accompanied by changes in gene expression, many factors that modulate megakaryopoiesis remain to be uncovered. Replication initiation determinant protein (RepID) which has multiple histone-code reader including bromodomain, cryptic Tudor domain and WD40 domains and Cullin 4-RING E3 ubiquitin ligase complex (CRL4) recruited to chromatin mediated by RepID have potential roles in gene expression changes via epigenetic regulations. We aimed to investigate whether RepID-CRL4 participates in transcriptional changes required for MK differentiation. METHODS: The PCR array was performed using cDNAs derived from RepID-proficient or RepID-deficient K562 erythroleukemia cell lines. Correlation between RepID and DAB2 expression was examined in the Cancer Cell Line Encyclopedia (CCLE) through the CellMinerCDB portal. The acceleration of MK differentiation in RepID-deficient K562 cells was determined by estimating cell sizes as well as counting multinucleated cells known as MK phenotypes, and by qRT-PCR analysis to validate transcripts of MK markers using phorbol 12-myristate 13-acetate (PMA)-mediated MK differentiation condition. Interaction between CRL4 and histone methylation modifying enzymes were investigated using BioGRID database, immunoprecipitation and proximity ligation assay. Alterations of expression and chromatin binding affinities of RepID, CRL4 and histone methylation modifying enzymes were investigated using subcellular fractionation followed by immunoblotting. RepID-CRL4-JARID1A-based epigenetic changes on DAB2 promoter were analyzed by chromatin-immunoprecipitation and qPCR analysis. RESULTS: RepID-deficient K562 cells highly expressing MK markers showed accelerated MKs differentiation exhibiting increases in cell size, lobulated nuclei together with reaching maximum levels of MK marker expression earlier than RepID-proficient K562 cells. Recovery of WD40 domain-containing RepID constructs in RepID-deficient background repressed DAB2 expression. CRL4A formed complex with histone H3K4 demethylase JARID1A in soluble nucleus and loaded to the DAB2 promoter in a RepID-dependent manner during proliferation condition. RepID, CRL4A, and JARID1A were dissociated from the chromatin during MK differentiation, leading to euchromatinization of the DAB2 promoter. CONCLUSION: This study uncovered a role for the RepID-CRL4A-JARID1A pathway in the regulation of gene expression for MK differentiation, which can form the basis for the new therapeutic approaches to induce platelet production. Video Abstract.

RepID represses megakaryocytic differentiation by recruiting CRL4A-JARID1A at DAB2 promoter.

Background Megakaryocytes (MKs) are platelet precursors, which arise from hematopoietic stem cells (HSCs). While MK lineage commitment and differentiation are accompanied by changes in gene expression, many factors that modulate megakaryopoiesis remain to be uncovered. Replication origin binding protein (RepID) which has multiple histone-code reader including bromodomain, cryptic Tudor domain and WD40 domains and Cullin 4-RING ubiquitin ligase complex (CRL4) recruited to chromatin mediated by RepID have potential roles in gene expression changes via epigenetic regulations. We aimed to investigate whether RepID-CRL4 participates in transcriptional changes required for MK differentiation. Methods The PCR array was performed using cDNAs derived from RepID-proficient or RepID-deficient K562 erythroleukemia cell lines. Correlation between RepID and DAB2 expression was examined in the Cancer Cell Line Encyclopedia (CCLE) through the CellMinerCDB portal. The acceleration of MK differentiation in RepID-deficient K562 cells was determined by estimating cell sizes as well as counting multinucleated cells known as MK phenotypes, and by qRT-PCR analysis to validate transcripts of MK markers using phorbol 12-myristate 13-acetate (PMA)-mediated MK differentiation condition. Interaction between CRL4 and histone methylation modifying enzymes were investigated using BioGRID database, immunoprecipitation and proximity ligation assay. Alterations of expression and chromatin binding affinities of RepID, CRL4 and histone methylation modifying enzymes were investigated using subcellular fractionation followed by immunoblotting. RepID-CRL4-JARID1A-based epigenetic changes on DAB2 promoter were analyzed by chromatin-immunoprecipitation and qPCR analysis. Results RepID-deficient K562 cells highly expressing MK markers showed accelerated MKs differentiation exhibiting increases in cell size, lobulated nuclei together with reaching maximum levels of MK marker expression earlier than RepID-proficient K562 cells. Recovery of WD40 domain-containing RepID constructs in RepID-deficient background repressed DAB2 expression. CRL4A formed complex with histone H3K4 demethylase JARID1A in soluble nucleus and loaded to the DAB2 promoter in a RepID-dependent manner during proliferation condition. RepID, CRL4A, and JARID1A were dissociated from the chromatin during MK differentiation, leading to euchromatinization of the DAB2 promoter. Conclusion This study uncovered a role for the RepID-CRL4A-JARID1A pathway in the regulation of gene expression for MK differentiation, which can form the basis for the new therapeutic approaches to induce platelet production.

c-Abl Regulates the Pathological Deposition of TDP-43 via Tyrosine 43 Phosphorylation.

Non-receptor tyrosine kinase, c-Abl plays a role in the pathogenesis of several neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. Here, we found that TDP-43, which was one of the main proteins comprising pathological deposits in amyotrophic lateral sclerosis (ALS), is a novel substrate for c-Abl. The phosphorylation of tyrosine 43 of TDP-43 by c-Abl led to increased TDP-43 levels in the cytoplasm and increased the formation of G3BP1-positive stress granules in SH-SY5Y cells. The kinase-dead mutant of c-Abl had no effect on the cytoplasmic localization of TDP-43. The expression of phosphor-mimetic mutant Y43E of TDP-43 in primary cortical neurons accumulated the neurite granule. Furthermore, the phosphorylation of TDP-43 at tyrosine 43 by c-Abl promoted the aggregation of TDP-43 and increased neuronal cell death in primary cortical neurons, but not in c-Abl-deficient primary cortical neurons. Identification of c-Abl as the kinase of TDP43 provides new insight into the pathogenesis of ALS.

Differential dynamics of cullin deneddylation via COP9 signalosome subunit 5 interaction.

Cullin-RING E3 ubiquitin ligases (CRLs) spatiotemporally regulate the proteasomal degradation of numerous cellular proteins involved in cell cycle control, DNA replication, and maintenance of genome stability. Activation of CRLs is controlled via neddylation by NEDD8-activating, -conjugating, and -attaching enzymes to the C-terminus of scaffold cullins (CULs), whereas the COP9 signalosome (CSN) inactivates CRLs via deneddylation. Here, we show that the deneddylation rate of each CUL is differentially modulated. Dose- or time-dependent treatment with pevonedistat, a small molecule inhibitor of NEDD8-activating enzyme (NAE), rapidly inhibits neddylation in most CULs, including CUL1, CUL3, CUL4A/B, and CUL5, whereas the deneddylation of CUL2 is slowly increased. We revealed that the different deneddylation speeds of each CUL depend on its binding strength with CSN5, the catalytic core of the CSN complex. Immunoprecipitation analysis revealed that CUL2 has a lower binding affinity for CSN5 than other CULs. Consistently, released cells treated with CSN5 inhibitor showed that CUL2 was slowly converted to the deneddylated form compared to the rapid deneddylation of other CULs. These findings provide mechanistic insights into the different dynamics of CULs in neddylation-deneddylation conversion.

The differentially expressed gene signatures of the Cullin 3-RING ubiquitin ligases in neuroendocrine cancer.

Cullin-RING ubiquitin E3 ligase (CRLs) composed of four components including cullin scaffolds, adaptors, substrate receptors, and RING proteins mediates the ubiquitination of approximately 20% of cellular proteins that are involved in numerous biological processes. While CRLs deregulation contributes to the pathogenesis of many diseases, including cancer, how CRLs deregulation occurs is yet to be fully investigated. Here, we demonstrate that components of CRL3 and its transcriptional regulators are possible prognosis marker of neuroendocrine (NE) cancer. Analysis of Cancer Cell Line Encyclopedia (CCLE) through the CellMinerCDB portal revealed that expression of CRL3 scaffold Cullin 3 (CUL3) highly correlates with NE signature, and CUL3 silencing inhibited NE cancer proliferation. Moreover, subset of 151 BTB (Bric-a-brac, Tramtrack, Broad complex) domain-containing proteins that have dual roles as substrate receptors and adaptor subunits in CRL3, as well as the expression of transcription factors (TFs) that control the transcription of BTB genes were upregulated in NE cancer. Analysis using published ChIP-sequencing data in small cell lung cancer (SCLC), including NE or non-NE SCLC verified that gene promoter of candidates which show high correlation with NE signature enriched H3K27Ac. These observations suggest that CRL3 is a master regulator of NE cancer and knowledge of specifically regulated CRL3 genes in NE cancer may accelerate new therapeutic approaches.

TRIP12 ubiquitination of glucocerebrosidase contributes to neurodegeneration in Parkinson's disease.

Impairment in glucocerebrosidase (GCase) is strongly associated with the development of Parkinson's disease (PD), yet the regulators responsible for its impairment remain elusive. In this paper, we identify the E3 ligase Thyroid Hormone Receptor Interacting Protein 12 (TRIP12) as a key regulator of GCase. TRIP12 interacts with and ubiquitinates GCase at lysine 293 to control its degradation via ubiquitin proteasomal degradation. Ubiquitinated GCase by TRIP12 leads to its functional impairment through premature degradation and subsequent accumulation of α-synuclein. TRIP12 overexpression causes mitochondrial dysfunction, which is ameliorated by GCase overexpression. Further, conditional TRIP12 knockout in vitro and knockdown in vivo promotes the expression of GCase, which blocks α-synuclein preformed fibrils (α-syn PFFs)-provoked dopaminergic neurodegeneration. Moreover, TRIP12 accumulates in human PD brain and α-synuclein-based mouse models. The identification of TRIP12 as a regulator of GCase provides a new perspective on the molecular mechanisms underlying dysfunctional GCase-driven neurodegeneration in PD.

A Novel, Selective c-Abl Inhibitor, Compound 5, Prevents Neurodegeneration in Parkinson's Disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder that affects movement. The nonreceptor tyrosine kinase c-Abl has shown a potential role in the progression of PD. As such, c-Abl inhibition is a promising candidate for neuroprotection in PD and α-synucleinopathies. Compound 5 is a newly synthesized blood-brain barrier penetrant c-Abl inhibitor with higher efficacy than existing inhibitors. The objective of the current study was to demonstrate the neuroprotective effects of compound 5 on the α-synuclein preformed fibril (α-syn PFF) mouse model of PD. Compound 5 significantly reduced neurotoxicity, activation of c-Abl, and Lewy body pathology caused by α-syn PFF in cortical neurons. Additionally, compound 5 markedly ameliorated the loss of dopaminergic neurons, c-Abl activation, Lewy body pathology, neuroinflammatory responses, and behavioral deficits induced by α-syn PFF injection in vivo. Taken together, these results suggest that compound 5 could be a pharmaceutical agent to prevent the progression of PD and α-synucleinopathies.

Complement and Coagulation Cascades are Potentially Involved in Dopaminergic Neurodegeneration in α-Synuclein-Based Mouse Models of Parkinson's Disease.

Parkinson's disease (PD) is the second most common neurodegenerative disorder that results in motor dysfunction and, eventually, cognitive impairment. α-Synuclein protein is known as a central protein to the pathophysiology of PD, but the underlying pathological mechanism still remains to be elucidated. In an effort to understand how α-synuclein underlies the pathology of PD, various PD mouse models with α-synuclein overexpression have been developed. However, systemic analysis of the brain proteome of those mouse models is lacking. In this study, we established two mouse models of PD by injecting α-synuclein preformed fibrils (PFF) or by inducing overexpression of human A53T α-synuclein to investigate common pathways in the two different types of the PD mouse models. For more accurate quantification of mouse brain proteome, the proteins were quantified using the method of stable isotope labeling with amino acids in mammals . We identified a total of 8355 proteins from the two mouse models; ∼6800 and ∼7200 proteins from α-synuclein PFF-injected mice and human A53T α-synuclein transgenic mice, respectively. Through pathway analysis of the differentially expressed proteins common to both PD mouse models, it was discovered that the complement and coagulation cascade pathways were enriched in the PD mice compared to control animals. Notably, a validation study demonstrated that complement component 3 (C3)-positive astrocytes were increased in the ventral midbrain of the intrastriatal α-synuclein PFF-injected mice and C3 secreted from astrocytes could induce the degeneration of dopaminergic neurons. This is the first study that highlights the significance of the complement and coagulation pathways in the pathogenesis of PD through proteome analyses with two sophisticated mouse models of PD.

Transneuronal Propagation of Pathologic α-Synuclein from the Gut to the Brain Models Parkinson's Disease.

Analysis of human pathology led Braak to postulate that α-synuclein (α-syn) pathology could spread from the gut to brain via the vagus nerve. Here, we test this postulate by assessing α-synucleinopathy in the brain in a novel gut-to-brain α-syn transmission mouse model, where pathological α-syn preformed fibrils were injected into the duodenal and pyloric muscularis layer. Spread of pathologic α-syn in brain, as assessed by phosphorylation of serine 129 of α-syn, was observed first in the dorsal motor nucleus, then in caudal portions of the hindbrain, including the locus coeruleus, and much later in basolateral amygdala, dorsal raphe nucleus, and the substantia nigra pars compacta. Moreover, loss of dopaminergic neurons and motor and non-motor symptoms were observed in a similar temporal manner. Truncal vagotomy and α-syn deficiency prevented the gut-to-brain spread of α-synucleinopathy and associated neurodegeneration and behavioral deficits. This study supports the Braak hypothesis in the etiology of idiopathic Parkinson's disease (PD).