# Inhibition of KDM2/7 Promotes Notochordal Differentiation of hiPSCs

## TL;DR

Scientists found that blocking specific enzymes helps human stem cells turn into notochord-like cells, which could aid in regenerating damaged spinal discs.

## Contribution

The study identifies KDM2/7 inhibition as a novel method to enhance notochordal differentiation of hiPSCs.

## Key findings

- Inhibiting KDM2A and KDM7A/B improves hiPSC differentiation into notochordal-like cells.
- Histone methylation regulation is a key driver in this differentiation process.
- CRISPR/Cas9-generated mCherry-reporter hiPSCs were successfully differentiated into notochordal-like cells.

## Abstract

Intervertebral disc disease (IDD) is a debilitating spine condition that can be caused by intervertebral disc (IVD) damage which progresses towards IVD degeneration and dysfunction. Recently, human pluripotent stem cells (hPSCs) were recognized as a valuable resource for cell-based regenerative medicine in skeletal diseases. Therefore, adult somatic cells reprogrammed into human induced pluripotent stem cells (hiPSCs) represent an attractive cell source for the derivation of notochordal-like cells (NCs) as a first step towards the development of a regenerative therapy for IDD. Utilizing a differentiation method involving treatment with a four-factor cocktail targeting the BMP, FGF, retinoic acid, and Wnt signaling pathways, we differentiate CRISPR/Cas9-generated mCherry-reporter knock-in hiPSCs into notochordal-like cells. Comprehensive analysis of transcriptomic changes throughout the differentiation process identified regulation of histone methylation as a pivotal driver facilitating the differentiation of hiPSCs into notochordal-like cells. We further provide evidence that specific inhibition of histone demethylases KDM2A and KDM7A/B enhanced the lineage commitment of hiPSCs towards notochordal-like cells. Our results suggest that inhibition of KDMs could be leveraged to alter the epigenetic landscape of hiPSCs to control notochord-specific gene expression. Thus, our study highlights the importance of epigenetic regulators in stem cell-based regenerative approaches for the treatment of disc degeneration.