Directed Differentiation of Notochord-like and Nucleus Pulposus-like Cells Using Human Pluripotent Stem Cells

Abstract

Summary: Intervertebral disc degeneration might be amenable to stem cell therapy, but the required cells are scarce. Here, we report the development of a protocol for directed in vitro differentiation of human pluripotent stem cells (hPSCs) into notochord-like and nucleus pulposus (NP)-like cells of the disc. The first step combines enhancement of ACTIVIN/NODAL and WNT and inhibition of BMP pathways. By day 5 of differentiation, hPSC-derived cells express notochordal cell characteristic genes. After activating the TGF-β pathway for an additional 15 days, qPCR, immunostaining, and transcriptome data show that a wide array of NP markers are expressed. Transcriptomically, the in vitro-derived cells become more like in vivo adolescent human NP cells, driven by a set of influential genes enriched with motifs bound by BRACHYURY and FOXA2, consistent with an NP cell-like identity. Transplantation of these NP-like cells attenuates fibrotic changes in a rat disc injury model of disc degeneration. : Zhang et al. report notochord-like and nucleus pulposus (NP)-like cells can be derived from human pluripotent stem cells using a NOTO-eGFP reporter system and a compound-defined protocol. These derived NP-like cells share high similarities with adolescent human NP cells and attenuate injury-induced intervertebral disc degeneration after transplantation. Keywords: human induced pluripotent stem cells, intervertebral disc disease, nucleus pulposus (NP)-like cells, notochord-like cells (NCLs), directed differentiation