For scRNA-seq: The NP and surrounding transition zone (n = 3 injured and 3 non-injured discs) were isolated and manually morselized to ~1mm^3 pieces. The tissue was then enzymatically digested for 1 hour at 37°C in 2 mg/mL of Pronase Protease (Millipore, Temecula, CA) in growth media containing 1% antibiotic-antimycotic solution (Gibco, Carlsbad, CA) and 10% fetal bovine serum (FBS, Gemini Bioproducts, West Sacramento, CA) in Dulbecco's modified eagle media-F12 media (DMEM/F12, GIBCO, Carlsbad, CA), followed by an ~18 hours digestion at 37°C in 0.25 mg/mL of Collagenase Type 1S (Sigma Aldrich) in growth media. The resulting sample was pushed through a 70μm cell strainer, and cells were isolated via centrifugation at 300G for ten minutes. The pellet was resuspended in phosphate-buffered saline at a concentration of 1,500 cells/uL. For bulk RNA-seq (both DRGs and IVD): Total RNA for the nucleus pulposus and dorsal root ganglia were collected using a RNeasy Lipid Tissue Mini Kit (Qiagen, Hilden, Germany) following the manufacturer protocol. The isolated RNA was transcribed into cDNA using a high-capacity reverse transcription kit (Applied Biosystems, Waltham, MA). Pig Taqman gene expression assays (Thermo Fisher Scientific) as detailed in Supplemental materials were used for analysis (Supplemental Table 2). All assays were normalized to 18S housekeeping gene. Single cell suspensions were stained with ViaStain AOPI Staining Solution (Nexcelom Bioscience, Lawrence, MA) and imaged on an EVOS M7000 Imaging System (Thermo Fisher Scientific, Waltham, CA) to determine cell suspension quality and cell viability.  Cell suspensions with a minimum viability of 70% were partitioned (10,000 target capture) into Gel Beads-in-emulsion (GEMs) on the Chromium X (10x Genomics, Pleasanton, CA) per the Chromium NextGEM Single Cell 3' v3.1 Gene Expression kit user guide.  Following reverse transcription and cDNA amplification, single cell libraries were prepared on the Chromium Connect (10x Genomics) using the Automated Gene Expression Library Construction kit (10x Genomics).  Barcoded libraries were quantified by quantitative PCR using the Collibri Library Quantification Kit (Thermo Fisher Scientific) and library size was measured via the 4200 TapeStation (Agilent Technologies, Santa Clara, CA).  Libraries were sequenced on a NovaSeq 6000 or X Plus (Illumina, San Diego, CA) with sequencing configuration 28x10x10x90bp, and a sequencing depth of 50,000 reads/cell. Bulk RNA seq for DRGs: RNA integrity was analyzed on the 2100 Bioanalyzer using the Agilent RNA 6000 Nano Kit (Agilent Technologies, Santa Clara, CA) and RNA quantified using the Qubit RNA HS Assay Kit (ThermoFisher Scientific, Waltham, MA).  Four hundred ng RNA was ribodepleted using the Lexogen RiboCop Depletion Kit Human/Mouse/Rat v2 kit (Lexogen Inc., Greenland, NH).  Stranded RNA-Seq library construction was performed using the IDT xGen Broad-Range RNA Library Prep Kit (Integrated DNA Technologies, Coralville, IA) with 11 cycles of PCR amplification.  Library concentration was measured via the Qubit 1X dsDNA HS Assay kit, and library size on the Agilent 4200 TapeStation (Agilent Technologies) with the Agilent HS D1000 ScreenTape.  Multiplexed libraries were pooled and sequenced on a NovaSeq 6000 (Illumina, San Diego, CA) using 1x75bp sequencing at 50M reads/sample. Bulk RNA-se2q for IVD: RNA integrity was analyzed on the 2100 Bioanalyzer using the Agilent RNA 6000 Pico Kit (Agilent Technologies, Santa Clara, CA) and RNA quantified using the Qubit RNA HS Assay Kit (ThermoFisher Scientific, Waltham, MA).  Library construction was performed using the SMARTer Stranded Total RNA-Seq Kit v3 – Pico Input Mammalian kit (Takara Bio USA, Inc., Mountain View, CA).  Three ng of total RNA was used for library construction with 13 cycles of PCR amplification.  Final libraries were quantified via the Qubit 1X dsDNA HS Assay kit and analyzed for size on the 4200 TapeStation (Agilent Technologies) with the Agilent HS D1000 ScreenTape.  Multiplexed libraries were pooled and sequenced on a NovaSeq 6000 (Illumina, San Diego, CA) using 1x75bp sequencing at 50M reads/sample.