Professor David Rowitch, Department of Paediatrics and Wellcome-MRC Cambridge Stem Cell Institute, Cambridge UK

Commentary

The human brain contains almost 100 billion neurons that have become specialised to carry out different functions such as cognition, control of voluntary movement, memory and so on. My laboratory was interested in understanding how CDKL5 genes are turned on and off in each of these neurons across the brain. We developed a new technique that allows us to count the number of molecules of mRNA that each can make a CDKL5 protein, within single neurons across the entire cortex of the mouse brain. We find that CDKL5 genes are turned on and off in a dynamic manner as the mouse brain develops. We are able to tell with great precision how levels of the gene differ between the many different subtypes of specialised neurons. This work will help us better understand the function that CDKL5 plays in very specific ways in sections of the brain that are dedicated to specialised function.

This research was funded by a grant from the Loulou Foundation and was recently published in Nature Neuroscience.

Work in the Rowitch laboratory investigates the precise way that the CDKL5 gene is expressed in neurons of the brain. This will help us plan for future gene therapy. Professor Rowitch leads the Department of Pediatrics at Cambridge University, where there are plans to build new facilities for delivery of gene therapy safely into the brain of children that can support eventual clinical trials for CDKL5 gene therapy.

References

Bayraktar O, Bartels T, Holmqvist S, Kleshchevnikov V, Martirosyan A, Polioudakis D, Ben Haim L, Young A, Batiuk M, Prakash K, Brown A, Roberts K, Paredes M, Kawaguchi R, Stockley J, Sabeur K, Chang S, Huang E, Hutchinson P, Ullian E, Hemberg M, Coppola G, Holt M, Geschwind D, Rowitch D. Astrocyte layers in the mammalian cerebral cortex revealed by a single-cell in situ transcriptomic map. Nature Neuroscience. 2020;23(4):500-509.

Original abstract

Original article: Astrocyte layers in the mammalian cerebral cortex revealed by a single-cell in situ transcriptomic map

Although the cerebral cortex is organized into six excitatory neuronal layers, it is unclear whether glial cells show distinct layering. In the present study, we developed a high-content pipeline, the large-area spatial transcriptomic (LaST) map, which can quantify single-cell gene expression in situ. Screening 46 candidate genes for astrocyte diversity across the mouse cortex, we identified superficial, mid and deep astrocyte identities in gradient layer patterns that were distinct from those of neurons. Astrocyte layer features, established in the early postnatal cortex, mostly persisted in adult mouse and human cortex. Single-cell RNA sequencing and spatial reconstruction analysis further confirmed the presence of astrocyte layers in the adult cortex. Satb2 and Reeler mutations that shifted neuronal post-mitotic development were sufficient to alter glial layering, indicating an instructive role for neuronal cues. Finally, astrocyte layer patterns diverged between mouse cortical regions. These findings indicate that excitatory neurons and astrocytes are organized into distinct lineage-associated laminae.

Conflict of interest statement

None

Links to scientific terms

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