Three-dimensional co-culturing reveals human stem cell-derived somatostatin interneurons with subclass expression

Area of Science:

• Neuroscience
• Stem Cell Biology
• Developmental Biology

Background:

• Deficiencies in cortical interneurons, especially somatostatin (SST) subtypes, are linked to neurological and neuropsychiatric disorders.
• Deriving SST interneurons in vitro from human embryonic stem cells (hESCs) is challenging due to late developmental timing and glial cell dependence.

Purpose of the Study:

• To develop an advanced in vitro model for generating functional human SST interneurons.
• To enable long-term development, functional maturation, and neuron-glial interactions of hESC-derived interneurons.

Main Methods:

• Established a three-dimensional (3D) co-culture system for hESC-derived neurons.
• Utilized single-nuclei RNA sequencing to characterize differentiated SST interneuron subclasses.
• Transplanted hESC-derived interneuron progenitors into forebrain organoids to assess maturation and fate specification.

Main Results:

• Successfully differentiated hESCs into functional GABAergic interneurons expressing SST within 50 days.
• Identified novel SST subclasses, including Martinotti and long-projecting neurons, in hESC cultures via transcriptomic analysis.
• Demonstrated that transplanted interneuron progenitors mature functionally and retain subclass identity within forebrain organoids.

Conclusions:

• The developed 3D co-culture model is a robust platform for studying human SST interneurons.
• This model supports the investigation of SST interneuron roles in health and neurological disease.
• Findings suggest cell-intrinsic fate specification mechanisms for SST interneuron subclasses.