Discovery of Inhibitors of Microglial Neurotoxicity Acting Through Multiple Mechanisms Using a Stem-Cell-Based Phenotypic Assay

Abstract

Stem cells, through their ability to both self-renew and differentiate, can produce a virtually limitless supply of specialized cells that behave comparably to primary cells. We took advantage of this property to develop an assay for small-molecule-based neuroprotection using stem-cell-derived motor neurons and astrocytes, together with activated microglia as a stress paradigm. Here, we report on the discovery of hit compounds from a screen of more than 10,000 small molecules. These compounds act through diverse pathways, including the inhibition of nitric oxide production by microglia, activation of the Nrf2 pathway in microglia and astrocytes, and direct protection of neurons from nitric-oxide-induced degeneration. We confirm the activity of these compounds using human neurons. Because microglial cells are activated in many neurological disorders, our hit compounds could be ideal starting points for the development of new drugs to treat various neurodegenerative and neurological diseases.

Impact of lifetime opioid exposure on arterial stiffness and vascular age: cross-sectional and longitudinal studies in men and women

“…Some of the pathways activated downstream by TLR4 signalling include the cyclooxygenase, lipooxygenase, MAP kinase (JNK and P38), AP-1, inducible nitric oxide synthase (iNOS), phosphoinositol-3 kinase (PI3K) and TGFβ pathways72 many of which have been noted to be stimulated within the first few minutes of TLR4 ligation73 to be stimulated by opioids70 72 and to be associated with potentiating the effects of ageing 51 74. Many of these immune products directly exacerbate the stem cell blockade 75. This then implies that opioid dependency may be conceptualised as chronically, if largely subclinically, ill.…”

Human induced pluripotent stem cells for modelling neurodevelopmental disorders

“…It is likely that the predictive validity of this system will only increase as the neurons used become more sophisticated and more accurately representative of human neurons. Groups have exploited neurobiological phenotypes they found in patient-derived neurons to conduct high-throughput genetic screens for compensatory mutations and potential drug targets 176–180 . In contrast, the majority of current subtype characterization for clinical trials is done almost entirely through notoriously imprecise clinical diagnostic criteria.…”

State-of-the-art of 3D cultures (organs-on-a-chip) in safety testing and pathophysiology

“…the presence of glial cells is of utmost importance since they can be both targets and mediators of chemically induced brain injury. Moreover, the presence of glia may affect or modulate the toxicity of chemicals for neurons (e.g., eskes et al, 2003;Giordano et al, 2009;Kuegler et al, 2012Kuegler et al, , 2010Schildknecht et al, 2009;Viviani et al, 1998;Zurich et al, 2004Zurich et al, , 2002Zurich et al, , 1998, or they may be drivers of neuro-inflammation (e.g., Boillee et al, 2006a,b;Falsig et al, 2004Falsig et al, , 2008Henn et al, 2011Henn et al, , 2009Hoing et al, 2012;Monnet-tschudi et al, 2007). the proportion of the different types of glial cells is also an important factor since it modulates the release of bioactive molecules upon toxic exposure Simon et al, 2002).…”