# Extrinsic apoptosis and necroptosis in telencephalic development: a single-cell mass cytometry study

## TL;DR

The study uses single-cell mass cytometry to show that both extrinsic apoptosis and necroptosis play roles in shaping the developing mouse brain.

## Contribution

The study reveals that combined deletion of RIPK3 and Caspase-8 increases cell count, challenging the idea that intrinsic apoptosis alone controls developmental cell death.

## Key findings

- Combined deletion of RIPK3 and Caspase-8 increases total cell count by 12.6%.
- DKO mice show selective enrichment of Tbr2⁺ intermediate progenitors and endothelial cells.
- Extrinsic apoptosis and necroptosis have distinct, cell-type-specific roles in telencephalic development.

## Abstract

Regulated cell death is integral to sculpting the developing brain, yet the relative contributions of extrinsic apoptosis and necroptosis remain unclear. Here, we leverage single-cell mass cytometry (CyTOF) to characterize the cellular landscape of the mouse telencephalon in wild-type (WT), RIPK3 knockout (RIPK3 KO), and RIPK3/Caspase-8 double knockout (DKO) mice. Strikingly, combined deletion of RIPK3 and Caspase-8 leads to a 12.6% increase in total cell count, challenging the prevailing notion that intrinsic apoptosis exclusively governs developmental cell elimination. Detailed subpopulation analysis reveals that DKO mice display selective enrichment of Tbr2⁺ intermediate progenitors and endothelial cells, underscoring distinct, cell type–specific roles for extrinsic apoptotic and necroptotic pathways. These findings provide a revised framework for understanding the coordinated regulation of cell number during telencephalic development and suggest potential mechanistic links to neurodevelopmental disorders characterized by aberrant cell death.