Down syndrome (DS) is a genetic disorder that causes cognitive impairment. The staggering effects associated with an extra copy of human chromosome 21 (HSA21) complicates mechanistic understanding of DS pathophysiology. We examined the neuron-astrocyte interplay in a fully recapitulated HSA21 trisomy cellular model differentiated from DS-patient-derived induced pluripotent stem cells (iPSCs). By combining calcium imaging with genetic approaches, we discovered the functional defects of DS astroglia and their effects on neuronal excitability. Compared with control isogenic astroglia, DS astroglia exhibited more-frequent spontaneous calcium fluctuations, which reduced the excitability of co-cultured neurons. Furthermore, suppressed neuronal activity could be rescued by abolishing astrocytic spontaneous calcium activity either chemically by blocking adenosine-mediated signaling or genetically by knockdown of inositol triphosphate (IP) receptors or S100B, a calcium binding protein coded on HSA21. Our results suggest a mechanism by which DS alters the function of astrocytes, which subsequently disturbs neuronal excitability.
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http://dx.doi.org/10.1016/j.celrep.2018.06.033 | DOI Listing |
bioRxiv
December 2024
Department of Biology, University of Miami, 1301 Memorial Drive, Coral Gables, FL 33146.
Animals alter their behavior in response to changes in the environment. Upon encountering hyperosmotic conditions, the nematode worm initiates avoidance and cessation of egg-laying behavior. While the sensory pathway for osmotic avoidance is well-understood, less is known about how egg laying is inhibited.
View Article and Find Full Text PDFConditioned suppression is a useful paradigm for measuring learned avoidance. In most conditioned suppression studies, forward conditioning is used where a cue predicts an aversive stimulus. However, backward conditioning, in which an aversive stimulus predicts a cue, provides unique insights into learned avoidance due to its influence on both conditioned excitation and inhibition.
View Article and Find Full Text PDFNeurons require high amounts energy, and mitochondria help to fulfill this requirement. Dysfunc-tional mitochondria trigger problems in various neuronal tasks. Using the neuromuscular junction (NMJ) as a model synapse, we previously reported that Mitochondrial Complex I (MCI) subunits were required for maintaining NMJ function and growth.
View Article and Find Full Text PDFCureus
December 2024
Division of Dental Anesthesiology, Faculty of Dentistry Graduate School of Medicine and Dental Sciences, Niigata University, Niigata, JPN.
Background There are many reports of anatomical and physiological studies on trigeminal ganglion neurons, but few studies have analyzed temporal changes in the excitation of the trigeminal ganglion. This study aimed to establish an experimental system for spatial and temporal imaging analysis of the excitatory dynamics of trigeminal ganglion cells evoked by stimulation of a peripheral branch of the trigeminal nerve. Methods After excision of the trigeminal ganglion with the inferior alveolar nerve (IAN) from Sprague Dawley rats (seven to nine weeks old), 400-µm-thick slices of the trigeminal ganglion with the IAN were prepared.
View Article and Find Full Text PDFGenes Brain Behav
February 2025
Laboratory of Addiction Genetics, Department of Pharmaceutical Sciences and Center for Drug Discovery, Northeastern University, Boston, Massachusetts, USA.
Opioid use disorder is heritable, yet its genetic etiology is largely unknown. C57BL/6J and C57BL/6NJ mouse substrains exhibit phenotypic diversity in the context of limited genetic diversity which together can facilitate genetic discovery. Here, we found C57BL/6NJ mice were less sensitive to oxycodone (OXY)-induced locomotor activation versus C57BL/6J mice in a conditioned place preference paradigm.
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