Parkinson’s disease dementia (PDD) and dementia with Lewy bodies (DLB) are clinically and neuropathologically highly related α-synucleinopathies that collectively constitute the second leading cause of neurodegenerative dementias. Genetic and neuropathological studies directly implicate α-synuclein (αS) abnormalities in PDD and DLB pathogenesis. However, it is currently unknown how αS abnormalities contribute to memory loss, particularly since forebrain neuronal loss in PDD and DLB is less severe than in Alzheimer’s disease. Previously, we found that familial Parkinson’s disease-linked human mutant A53T αS causes aberrant localization of the microtubule-associated protein tau to postsynaptic spines in neurons, leading to postsynaptic deficits. Thus, we directly tested if the synaptic and memory deficits in a mouse model of α-synucleinopathy (TgA53T) are mediated by tau. TgA53T mice exhibit progressive memory deficits associated with postsynaptic deficits in the absence of obvious neuropathological and neurodegenerative changes in the hippocampus. Significantly, removal of endogenous mouse tau expression in TgA53T mice (TgA53T/mTau−/−), achieved by mating TgA53T mice to mouse tau-knockout mice, completely ameliorates cognitive dysfunction and concurrent synaptic deficits without affecting αS expression or accumulation of selected toxic αS oligomers. Among the known tau-dependent effects, memory deficits in TgA53T mice were associated with hippocampal circuit remodeling linked to chronic network hyperexcitability. This remodeling was absent in TgA53T/mTau−/− mice, indicating that postsynaptic deficits, aberrant network hyperactivity, and memory deficits are mechanistically linked. Our results directly implicate tau as a mediator of specific human mutant A53T αS-mediated abnormalities related to deficits in hippocampal neurotransmission and suggest a mechanism for memory impairment that occurs as a consequence of synaptic dysfunction rather than synaptic or neuronal loss. We hypothesize that these initial synaptic deficits contribute to network hyperexcitability which, in turn, exacerbate cognitive dysfunction. Our results indicate that these synaptic changes present potential therapeutic targets for amelioration of memory deficits in α-synucleinopathies.Electronic supplementary materialThe online version of this article (10.1007/s00401-019-02032-w) contains supplementary material, which is available to authorized users.

Purpose Ovarian cancer is the deadliest of the gynecological malignancies. Carcinogenic progression is accompanied by up-regulation of ubiquitin-dependent protein degradation machinery as a mechanism to compensate with elevated endogenous proteotoxic stress. Recent studies support the notion that deubiquitinating enzymes (DUBs) are essential factors in proteolytic degradation and that their aberrant activity is linked to cancer progression and chemoresistance. Thus, DUBs are an attractive therapeutic target for ovarian cancer. Experimental Design The potency and selectivity of RA-9 inhibitor for proteasome-associated DUBs was determined in ovarian cancer cell lines and primary cells. The anticancer activity of RA-9 and its mechanism of action was evaluated in multiple cancer cell lines in vitro and in vivo in immunodeficient mice bearing an intra-peritoneal ES-2 xenograft model of human ovarian cancer. Results Here we report the characterization of RA-9 as a small-molecule inhibitor of proteasome-associated DUBs. Treatment with RA-9 selectively induces onset of apoptosis, in ovarian cancer cell lines and primary cultures derived from donors. Loss of cell viability following RA-9 exposure is associated with an Unfolded Protein Response (UPR) as mechanism to compensate for unsustainable levels of proteotoxic stress. In vivo treatment with RA-9 retards tumor growth, increases overall survival and was well tolerated by the host. Conclusions Our preclinical studies support further evaluation of RA-9 as an ovarian cancer therapeutic.

UNC-45A, a highly conserved member of the UCS (UNC45A/CRO1/SHE4P) protein family of cochaperones, plays an important role in regulating cytoskeletal-associated functions in invertebrates and mammalian cells, including cytokinesis, exocytosis, cell motility, and neuronal development. Here, for the first time, UNC-45A is demonstrated to function as a mitotic spindle-associated protein that destabilizes microtubules (MT) activity. Using in vitro biophysical reconstitution and total internal reflection fluorescence microscopy analysis, we reveal that UNC-45A directly binds to taxol-stabilized MTs in the absence of any additional cellular cofactors or other MT-associated proteins and acts as an ATP-independent MT destabilizer. In cells, UNC-45A binds to and destabilizes mitotic spindles, and its depletion causes severe defects in chromosome congression and segregation. UNC-45A is overexpressed in human clinical specimens from chemoresistant ovarian cancer and that UNC-45A-overexpressing cells resist chromosome missegregation and aneuploidy when treated with clinically relevant concentrations of paclitaxel. Lastly, UNC-45A depletion exacerbates paclitaxel-mediated stabilizing effects on mitotic spindles and restores sensitivity to paclitaxel. Implications: These findings reveal novel and significant roles for UNC-45A in regulation of cytoskeletal dynamics, broadening our understanding of the basic mechanisms regulating MT stability and human cancer susceptibility to paclitaxel, one of the most widely used chemotherapy agents for the treatment of human cancers.

Malignant and atypical meningiomas are resistant to standard therapies and associated with poor prognosis. Despite progress in the treatment of other tumors with therapeutic vaccines, this approach has not been tested preclinically or clinically in these tumors. Spontaneous canine meningioma is a clinically meaningful but underutilized model for preclinical testing of novel strategies for aggressive human meningioma. We treated 11 meningioma-bearing dogs with surgery and vaccine immunotherapy consisting of autologous tumor cell lysate combined with toll-like receptor ligands. Therapy was well tolerated, and only one dog had tumor growth that required intervention, with a mean follow up of 585 days. Interferon gamma elaborating T cells were detected in the peripheral blood of two cases, but vaccine-induced tumor-reactive antibody responses developed in all dogs. Antibody responses were polyclonal, recognizing both intracellular and cell surface antigens, and heat shock protein 60 was identified as one common antigen. Tumor-reactive antibodies bound allogeneic canine and human meningiomas, demonstrating common antigens across breed and species. Histological analysis revealed robust infiltration of antibody-secreting plasma cells into the brain around the tumor in post-treatment compared to pre-treatment samples. Tumor-reactive antibodies were capable of inducing antibody dependent cell-mediated cytotoxicity to autologous and allogeneic tumor cells. These data demonstrate the feasibility and immunologic efficacy of vaccine immunotherapy for a large animal model of human meningioma and warrant further development towards human trials.

Background: Studies link c-Abl activation with the accumulation of pathogenic α-synuclein (αS) and neurodegeneration in Parkinson's disease (PD). Currently, c-Abl, a tyrosine kinase activated by cellular stress, is thought to promote αS pathology by either directly phosphorylating αS or by causing autophagy deficits. Methods: αS overexpressing transgenic (Tg) mice were used in this study. A53T Tg mice that express high levels of human mutant A53TαS under the control of prion protein promoter. Two different approaches were used in this study. Natural aging and seeding model of synucleinopathy. In seeding model, intracortical/intrastriatal (IC/IS) stereotaxic injection of toxic lysates was done using tissue lysates from end-stage symptomatic mice. In this study, nilotinib and pifithrin-α was used as a c-Abl and p53 inhibitor, respectively. Both Tg and non-transgenic (nTg) mice from each group were subjected to nilotinib (10 mg/kg) or vehicle (DMSO) treatment. Frozen brain tissues from PD and control human cases were analyzed. In vitro cells study was implied for c-Abl/p53 genetic manipulation to uncover signal transduction. Results: Herein, we show that the pathologic effects of c-Abl in PD also involve activation of p53, as c-Abl activation in a transgenic mouse model of α-synucleinopathy (TgA53T) and human PD cases are associated with the increased p53 activation. Significantly, active p53 in TgA53T neurons accumulates in the cytosol, which may lead to inhibition of autophagy. Thus, we hypothesized that c-Abl-dependent p53 activation contributes to autophagy impairment in α-synucleinopathy. In support of the hypothesis, we show that c-Abl activation is sufficient to inhibit autophagy in p53-dependent manner. Moreover, inhibition of either c-Abl, using nilotinib, or p53, using pifithrin-α, was sufficient to increase autophagic flux in neuronal cells by inducing phosphorylation of AMP-activated kinase (AMPK), ULK1 activation, and down-regulation of mTORC1 signaling. Finally, we show that pharmacological attenuation of c-Abl activity by nilotinib treatment in the TgA53T mouse model reduces activation of p53, stimulates autophagy, decreases accumulation αS pathology, and delays disease onset. Conclusion: Collectively, our data show that c-Abl activation by α-synucleinopathy causes p53 dependent autophagy deficits and both c-Abl and p53 represent therapeutic target for PD.

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Blast-induced traumatic brain injury (bTBI) is the "signature" injury of the recent Iraq and Afghanistan wars. Here, we present a novel method to induce bTBI using shock wave (SW) lithotripsy. Using a lithotripsy machine, Wistar rats (N = 70; 408.3 ± 93 g) received five SW pulses to the right side of the frontal cortex at 24 kV and a frequency of 60 Hz. Animals were then randomly divided into three study endpoints: 24 h (n = 25), 72 h (n = 19) and 168 h (n = 26). Neurological and behavioral assessments (Garcia's test, beam walking, Rotarod, and elevated plus maze) were performed at the baseline, and further assessments followed at 3, 6, 24, 72, and 168 h post-injury, if applicable. We performed digital subtraction angiography (DSA) to assess presence of cerebral vasospasm due to induced bTBI. Damage to brain tissue was assessed by an overall histological severity (OHS) score based on depth of injury, area of hemorrhage, and extent of axonal injury. Except for beam walking, OHS was significantly correlated with the other three outcome measures with at least one of their assessments during the first 6 h after the experiment. OHS manifested the highest absolute correlation coefficients with anxiety at the baseline and 6 h post-injury (r(baseline) = -0.75, r(6hrs) = 0.85; p<0.05). Median hemispheric differences for contrast peak values (obtained from DSA studies) for 24, 72, and 168 h endpoints were 3.45%, 3.05% and 0.2%, respectively, with statistically significant differences at 1 versus 7 d (p<0.05) and 3 versus 7 d (p<0.01). In this study, we successfully established a preclinical rat model of bTBI with characteristics similar to those observed in clinical cases. This new method may be useful for future investigations aimed at understanding bTBI pathophysiology.

Background Neuronal dysfunction and degeneration linked to α-synuclein (αS) pathology is thought to be responsible for the progressive nature of Parkinson’s disease and related dementia with Lewy bodies. Studies have indicated bidirectional pathological relationships between αS pathology and tau abnormalities. We recently showed that A53T mutant human αS (HuαS) can cause post-synaptic and cognitive deficits that require microtubule-associated protein tau expression. However, the role of tau in the development of αS pathology and subsequent neuronal dysfunction has been controversial. Herein, we set out to determine the role of tau in the onset and progression of αS pathology (α-synucleinopathy) using a transgenic mouse model of α-synucleinopathy lacking mouse tau expression. Methods Transgenic mice expressing A53T mutant HuαS (TgA53T) were crossed with mTau−/− mice to generate TgA53T/mTau−/−. To achieve more uniform induction of α-synucleinopathy in mice, we used intramuscular injections of αS preformed fibrils (PFF) in non-transgenic (nTg), TgA53T, TgA53T/mTau−/−, and mTau−/− mice. Motor behavior was analyzed at 70 days post inoculation (dpi) of PFF and tissues for biochemical and neuropathological analysis were collected at 40 dpi, 70 dpi, and end stage. Results Loss of tau expression significantly delayed the onset of motor deficits in the TgA53T model and the progression of α-synucleinopathy disease, as evidenced by a significant reduction in histopathological and behavioral markers of neurodegeneration and disease, and a significant improvement in survival. In vitro application of PFF to primary mouse hippocampal neurons demonstrated no changes in PFF uptake and processing or pS129 αS aggregation as a function of tau expression. However, PFF-induced neurotoxicity, including morphological deficits in nTg neurons, was prevented with tau removal. Conclusions Collectively, our data suggest that tau is likely acting downstream of αS pathology to affect neuronal homeostasis and survival. This work further supports the investigation of tau in α-synucleinopathies to identify novel disease-modifying therapeutic strategies.