Preclinical translational platform of neuroinflammatory disease biology relevant to neurodegenerative disease.

Neuroinflammation is a key driver of neurodegenerative disease, however the tools available to model this disease biology at the systems level are lacking. We describe a translational drug discovery platform based on organotypic culture of murine cortical brain slices that recapitulate disease-relevant neuroinflammatory biology. After an acute injury response, the brain slices assume a chronic neuroinflammatory state marked by transcriptomic profiles indicative of activation of microglia and astrocytes and loss of neuronal function. Microglia are necessary for manifestation of this neuroinflammation, as depletion of microglia prior to isolation of the brain slices prevents both activation of astrocytes and robust loss of synaptic function genes. The transcriptomic pattern of neuroinflammation in the mouse platform is present in published datasets derived from patients with amyotrophic lateral sclerosis, Huntington's disease, and frontotemporal dementia. Pharmacological utility of the platform was validated by demonstrating reversal of microglial activation and the overall transcriptomic signature with transforming growth factor-ß. Additional anti-inflammatory targets were screened and inhibitors of glucocorticoid receptors, COX-2, dihydrofolate reductase, and NLRP3 inflammasome all failed to reverse the neuroinflammatory signature. Bioinformatics analysis of the neuroinflammatory signature identified protein tyrosine phosphatase non-receptor type 11 (PTPN11/SHP2) as a potential target. Three structurally distinct inhibitors of PTPN11 (RMC-4550, TN0155, IACS-13909) reversed the neuroinflammatory disease signature. Collectively, these results highlight the utility of this novel neuroinflammatory platform for facilitating identification and validation of targets for neuroinflammatory neurodegenerative disease drug discovery.

Development of a high-throughput AlphaScreen assay for modulators of synapsin I phosphorylation in primary neurons.

Alterations in synaptic transmission have been implicated in a number of psychiatric and neurological disorders. The discovery of small-molecule modulators of proteins that regulate neurotransmission represents a novel therapeutic strategy for these diseases. However, high-throughput screening (HTS) approaches in primary neurons have been limited by challenges in preparing and applying primary neuronal cultures under conditions required for generating sufficiently robust and sensitive HTS assays. Synapsin I is an abundant presynaptic protein that plays a critical role in neurotransmission through tethering synaptic vesicles to the actin cytoskeleton. It has several phosphorylation sites that regulate its modulation of synaptic vesicle trafficking and, therefore, the efficacy of synaptic transmission. Here, we describe the development of a rapid, sensitive, and homogeneous assay to detect phospho-synapsin I (pSYN1) in primary cortical neurons in 384-well plates using AlphaScreen technology. From results of a pilot screening campaign, we show that the assay can identify compounds that modulate synapsin I phosphorylation via multiple signaling pathways. The implementation of the AlphaScreen pSYN1 assay and future development of additional primary neuronal HTS assays provides an attractive approach for discovery of novel classes of therapeutic candidates for a variety of CNS disorders.

Gng12 is a novel negative regulator of LPS-induced inflammation in the microglial cell line BV-2.

BACKGROUND: Inflammation plays a central role in many neurodegenerative diseases, including Parkinson's, Alzheimer's, multiple sclerosis, amyotrophic lateral sclerosis, and AIDS dementia. Microglia are the resident macrophages of the central nervous system and are the cells primarily responsible for the inflammatory component of these diseases. METHODS: Using gene expression profiling, we compared the profile of the neurospecific microglial cell line BV-2 after LPS stimulation to that of a macrophage cell line (J774A.1) stimulated with LPS. RESULTS: A set of 77 genes that were modulated only in microglial cells after LPS stimulation was identified. One gene of interest, Gng12, was investigated further to determine its ability to modify the inflammatory response. Specifically, Gng12 mRNA levels were transiently increased after LPS stimulation. In addition, overall levels of Gng12 mRNA after LPS stimulation were significantly higher in BV-2 cells as compared to macrophage cells. CONCLUSION: Modulating Gng12 mRNA levels using RNAi revealed a novel role for the factor in the negative regulation of the overall inflammatory response as based on effects on nitrite and TNFalpha levels. These data suggest that Gng12 is a negative regulator of the LPS response and may be an important factor in the overall inflammatory signaling cascade.