Single-Cell Phenotyping of Complex Heterogeneous Tissue

Development and Degeneration of the Intervertebral Disc—Insights from Across Species

“…Understanding the developmental origins and cellular composition of the IVD is important to grasp its contributions to the structural support and functionality it provides to the spine. Recent developments in the omics fields now facilitate a better understanding of cellular heterogeneity and cell metabolic functions on a molecular level and can provide a basis for better diagnostic tools to identify early IVDD onset including timing, symptoms and biomarkers in animals, especially large breeds [ 27 ]. Importantly, scRNA seq has tremendously improved understanding of cell population dynamics between healthy and degenerated discs and the type of cells populating the region.…”

“…Mouse fate-mapping and lineage tracing experiments demonstrated that the NP is a notochord (NC) derived tissue [ 3 , 25 , 26 ]. As such, the NP contains both NC-like cells and smaller chondrocyte (CC)-like cells contributing to a heterogenous cell population [ 14 , 27 , 28 , 29 , 30 ] with NC-like cells declining or disappearing in the matured IVD of some animals ( Figure 2 ) [ 14 , 27 , 31 ]. The NC also acts as an important transient structure influencing patterning of ventrolateral sclerotome cells during embryogenesis, which migrate on both sides of the embryonic midline to surround the NC with the axial sclerotome giving rise to AF cells of the IVD and portions of the vertebral body ( Figure 1 ) [ 9 , 29 , 32 , 33 ].…”

Glis1 and oxaloacetate in nucleus pulposus stromal cell somatic reprogramming and survival

“…Aside from impacting ECM organization and collagen fibrillogenesis, some of these proteins engage in inflammatory response pathways and the phosphatidylinositol-3-kinase (PI3K)/Akt and mammalian target of rapamycin (mTOR) signaling pathway critical for cell cycle regulation ( Ryu and Lee, 2017 ). Surprisingly, transcripts lower in NP over FAT/AF cells were associated with cell migration, despite NP cells being very mobile in monolayer culture ( Kraus et al, 2019b ).…”

“…RNA in situ hybridisation (RISH) was used for targeted transcript-based cell phenotyping on sectioned tissue (SISH) ( Kraus et al, 2001 ; Kraus et al, 2014 ; Kraus et al, 2019a ; Kraus et al, 2019b ), cells cultured on glass coverslips (CISH) ( Li et al, 2021 ), or in alginate beads (BISH). Briefly, the SISH tissues from more than three donors were fixed in 4% (w/v) PFA overnight at 4°C and then washed 3 × in 1X PBS for 5 min.…”