stereotaxic-surgery-for-genetic-manipulation-striatal-cells-neonatal

Stereotaxic Surgery for Genetic Manipulation in Striatal Cells of Neonatal Mouse Brains

Many genes are expressed in embryonic brains, and some of them are continuously expressed in the brain after birth. For such persistently expressed genes, ...

National Yang-Ming University

Cortico-basal ganglia circuits are critical for speech and language and are implicated in autism spectrum disorder, in which language function can be severely affected. We demonstrate that in the mouse striatum, the gene Foxp2 negatively interacts with the synapse suppressor gene Mef2c. We present causal evidence that Mef2c inhibition by Foxp2 in neonatal mouse striatum controls synaptogenesis of corticostriatal inputs and vocalization in neonates. Mef2c suppresses corticostriatal synapse formation and striatal spinogenesis, but can itself be repressed by Foxp2 through direct DNA binding. Foxp2 deletion de-represses Mef2c, and both intrastriatal and global decrease of Mef2c rescue vocalization and striatal spinogenesis defects of Foxp2-deletion mutants. These findings suggest that Foxp2-Mef2C signaling is critical to corticostriatal circuit formation. If found in humans, such signaling defects could contribute to a range of neurologic and neuropsychiatric disorders.

Foxp2 controls synaptic wiring of corticostriatal circuits and vocal communication by opposing Mef2c.

The striatum comprises two neurochemical compartments: striosomes and the matrix. Striosomal and matrix compartments receive inputs from limbic system-related and sensorimotor cortices, respectively. Here, we investigate the impact on the corticostriosomal pathway in the valproic acid (VPA)-induced autism spectrum disorder mouse model. VPA administration during the neurogenesis time windows of striosomes, but not the matrix, resulted in aberrant compartmentation [, maternal VPA injections at embryonic day (E)12.75 decreased μ-opioid receptor-positive striosomes, but increased calbindin-positive matrix in the rostral striatum]. VPA treatment also impaired the aggregation of cells pulse labeled with 5-bromo-2'-deoxyuridine at E12.75 into striosomal cell clusters, which suggests defective segregation of striosomal cells from matrix cells. This possibility was supported by our findings that VPA treatment altered the expression of ephrinA5 and EphA4, two molecules that are related to compartmental segregation. In the VPA neocortex, Foxp2-positive neurons were decreased in layer VI, but increased in layer V, which projects to the striosomal compartment. We also investigated VPA effects on the corticostriosomal pathway. VPA treatment decreased the putative corticostriosomal synapses of striosomal neurons and induced an aberrant pattern of isolation stress-induced ultrasonic vocalizations. Of interest, risperidone treatments conjointly improved ultrasonic vocalizations and restored the striosomal compartment in VPA pups. Collectively, dysfunctional corticostriatal pathways, particularly  the aberrant striosomal compartment, may be involved in autism spectrum disorder pathophysiology.-Kuo, H.-Y., Liu, F.-C. Valproic acid induces aberrant development of striatal compartments and corticostriatal pathways in a mouse model of autism spectrum disorder.

Article	Year
Foxp2 controls synaptic wiring of corticostriatal circuits and vocal communication by opposing Mef2c. Nature neuroscience\| PubMed ID: 27595386	2016
Valproic acid induces aberrant development of striatal compartments and corticostriatal pathways in a mouse model of autism spectrum disorder. FASEB journal : official publication of the Federation of American Societies for Experimental Biology\| PubMed ID: 28687613	2017

Hsiao-Ying Kuo

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