Peritoneal Amyloid as a Presenting Manifestation of AL Amyloid.

Amyloid is a systemic disease characterized by extracellular deposition of misfolded protein. Gastrointestinal and peritoneal deposition of light chain (AL) amyloid is an under-recognized manifestation of this systemic disease, usually as a late sequela. Here we present a case of recently diagnosed AL peritoneal amyloid that presented in the context of recurrent, acute onset abdominal discomfort and was found to have bowel obstruction complicated by perforation in the setting of AL-mediated gastrointestinal tract infiltration and dysmotility.

GL261 luciferase-expressing cells elicit an anti-tumor immune response: an evaluation of murine glioma models.

Preclinical models that reliably recapitulate the immunosuppressive properties of human gliomas are essential to assess immune-based therapies. GL261 murine glioma cells are widely used as a syngeneic animal model of glioma, however, it has become common practice to transfect these cells with luciferase for fluorescent tumor tracking. The aim of this study was to compare the survival of mice injected with fluorescent or non-fluorescent GL261 cells and characterize the differences in their tumor microenvironment. Mice were intracranially implanted with GL261, GL261 Red-FLuc or GL261-Luc2 cells at varying doses. Cytokine profiles were evaluated by proteome microarray and Kaplan-Meier survival analysis was used to determine survival differences. Median survival for mice implanted with 5 × 104 GL261 cells was 18 to 21 days. The GL261 Red-FLuc implanted mice cells did not reach median survival at any tumor dose. Mice injected with 3 × 105 GL261-Luc2 cells reached median survival at 23 days. However, median survival was significantly prolonged to 37 days in mice implanted with 5 × 104 GL261-Luc2 cells. Additionally, proteomic analyses revealed significantly elevated inflammatory cytokines in the supernatants of the GL261 Red-FLuc cells and GL261-Luc2 cells. Our data suggest that GL261 Red-FLuc and GL261-Luc2 murine models elicit an anti-tumor immune response by increasing pro-inflammatory modulators.

Biomarkers for immunotherapy for treatment of glioblastoma.

Immunotherapy is a promising new therapeutic field that has demonstrated significant benefits in many solid-tumor malignancies, such as metastatic melanoma and non-small cell lung cancer. However, only a subset of these patients responds to treatment. Glioblastoma (GBM) is the most common malignant primary brain tumor with a poor prognosis of 14.6 months and few treatment advancements over the last 10 years. There are many clinical trials testing immune therapies in GBM, but patient responses in these studies have been highly variable and a definitive benefit has yet to be identified. Biomarkers are used to quantify normal physiology and physiological response to therapies. When extensively characterized and vigorously validated, they have the potential to delineate responders from non-responders for patients treated with immunotherapy in malignancies outside of the central nervous system (CNS) as well as GBM. Due to the challenges of current modalities of radiographic diagnosis and disease monitoring, identification of new predictive and prognostic biomarkers to gauge response to immune therapy for patients with GBM will be critical in the precise treatment of this highly heterogenous disease. This review will explore the current and future strategies for the identification of potential biomarkers in the field of immunotherapy for GBM, as well as highlight major challenges of adapting immune therapy for CNS malignancies.

Taking a Bite Out of Amyloid: Mechanistic Insights into α-Synuclein Degradation by Cathepsin L.

A common hallmark of amyloids is their resistance to an array of proteases, highlighting the difficulty in degrading these disease-related aggregated proteinaceous materials. Here, we report on the potent activity of cathepsin L (CtsL), a lysosomal protease that proteolyzes the Parkinson's disease-related amyloid formed by α-synuclein (α-syn). Using liquid chromatography with mass spectrometry and transmission electron microscopy, an elegant mechanism is revealed on the residue and ultrastructural level, respectively. Specifically, CtsL always truncates α-syn fibrils first at the C-terminus before attacking the internal ß-sheet-rich region between residues 30 and 100. This suggests that only upon removal of the α-syn C-terminus can CtsL gain access to residues within the amyloid core. Interestingly, three of the four mapped sites contain a glycine residue (G36, G41, and G51) that is likely to be involved in a ß-turn in the fibril, whereupon cutting would lead to solvent exposure of internal residues and allow further proteolysis. Via close inspection of the fibril morphology, products resulting from CtsL degradation show imperfections along the fibril axis, with missing protein density as though they have been cannibalized. The ability of CtsL to degrade α-syn amyloid fibrils offers a promising strategy for improving the cellular clearance of aggregated α-syn through the modulation of protease levels and activity.

Acute exposure to chlorpyrifos caused NADPH oxidase mediated oxidative stress and neurotoxicity in a striatal cell model of Huntington's disease.

We hypothesized that expression of mutant Huntingtin (HTT) would modulate the neurotoxicity of the commonly used organophosphate insecticide, chlorpyrifos (CPF), revealing cellular mechanisms underlying neurodegeneration. Using a mouse striatal cell model of HD, we report that mutant HD cells are more susceptible to CPF-induced cytotoxicity as compared to wild-type. This CPF-induced cytotoxicity caused increased production of reactive oxygen species, reduced glutathione levels, decreased superoxide dismutase activity, and increased malondialdehyde levels in mutant HD cells relative to wild-type. Furthermore, we show that co-treatment with antioxidant agents attenuated the CPF-induced ROS levels and cytotoxicity. Co-treatment with a NADPH oxidase (NOX) inhibitor, apocynin, also attenuated the CPF-induced ROS production and neurotoxicity. CPF caused increased NOX activity in mutant HD lines that was ameliorated following co-treatment with apocynin. Finally, CPF-induced neurotoxicity significantly increased the protein expression of nuclear factor erythroid 2-related factor (Nrf2) in mutant HD cells as compared to wild-type. This study is the first report of CPF-induced toxicity in HD pathophysiology and suggests that mutant HTT and CPF exhibit a disease-toxicant interaction wherein expression of mutant HTT enhances CPF-induced neurotoxicity via a NOX-mediated oxidative stress mechanism to cause neuronal loss in the full length HTT expressing striatal cells.