Directed and efficient generation of calretinin interneurons from human pluripotent stem cells.

Background: Schizophrenia, autism, and epilepsy are associated with dysfunctions in cortical GABAergic interneurons. Calretinin-expressing interneurons, the most prominent type, constitute approximately 50% of human cortical GABAergic neurons and are closely linked to cognition. However, the difficulty in obtaining sufficient calretinin interneurons has significantly hindered the study of their development and functions. This study focuses on building an efficient protocol for generating calretinin interneurons, which is key to the brain development and regenerative medicine.

Methods: Neuroepithelial stem cells (NESCs) were firstly generated from human pluripotent stem cells (hPSCs) using a previously established protocol, and subsequently treated with sonic hedgehog (SHH), purmorphamine and IWP2 to induce differentiation into calretinin interneurons. Single-cell RNA sequencing (scRNA-seq) was employed to analyze the transcriptional profiles of these interneurons, while their functional properties were assessed via transplantation.

Results: We developed a robust protocol enabling the generation of approximately 80% calretinin interneurons from human pluripotent stem cells (hPSCs). NESCs were induced from hPSCs and differentiated into calretinin interneurons through modulation of Shh and Wnt signaling. These interneurons exhibited robust GABAergic action potentials. Upon transplantation, they successfully integrated into the mouse brain and matured into calretinin interneurons.

Conclusion: Our study presents an efficient protocol for generating calretinin interneurons from hPSCs, offering a valuable tool for investigating the development of calretinin interneurons. This approach holds potential for applications in regenerative medicine, disease modeling, and drug screening.