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Lufkin L, Samanta A, Baker D, Lufkin S, Schulze J, Ellis B, Rose J, Lufkin T, Kraus P. Glis1 and oxaloacetate in nucleus pulposus stromal cell somatic reprogramming and survival. Front Mol Biosci 2022; 9:1009402. [PMID: 36406265 PMCID: PMC9671658 DOI: 10.3389/fmolb.2022.1009402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 10/10/2022] [Indexed: 12/04/2022] Open
Abstract
Regenerative medicine aims to repair degenerate tissue through cell refurbishment with minimally invasive procedures. Adipose tissue (FAT)-derived stem or stromal cells are a convenient autologous choice for many regenerative cell therapy approaches. The intervertebral disc (IVD) is a suitable target. Comprised of an inner nucleus pulposus (NP) and an outer annulus fibrosus (AF), the degeneration of the IVD through trauma or aging presents a substantial socio-economic burden worldwide. The avascular nature of the mature NP forces cells to reside in a unique environment with increased lactate levels, conditions that pose a challenge to cell-based therapies. We assessed adipose and IVD tissue-derived stromal cells through in vitro transcriptome analysis in 2D and 3D culture and suggested that the transcription factor Glis1 and metabolite oxaloacetic acid (OAA) could provide NP cells with survival tools for the harsh niche conditions in the IVD.
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Affiliation(s)
- Leon Lufkin
- Department of Statistics and Data Science, Yale University, New Haven, CT, United States,The Clarkson School, Clarkson University, Potsdam, NY, United States
| | - Ankita Samanta
- Department of Biology, Clarkson University, Potsdam, NY, United States
| | - DeVaun Baker
- The Clarkson School, Clarkson University, Potsdam, NY, United States,Department of Biology, Clarkson University, Potsdam, NY, United States
| | - Sina Lufkin
- The Clarkson School, Clarkson University, Potsdam, NY, United States,Department of Biology, Clarkson University, Potsdam, NY, United States
| | | | - Benjamin Ellis
- Department of Biology, Clarkson University, Potsdam, NY, United States
| | - Jillian Rose
- Department of Biology, Clarkson University, Potsdam, NY, United States
| | - Thomas Lufkin
- Department of Biology, Clarkson University, Potsdam, NY, United States
| | - Petra Kraus
- Department of Biology, Clarkson University, Potsdam, NY, United States,*Correspondence: Petra Kraus,
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Single-Cell RNA-Seq Analysis of Cells from Degenerating and Non-Degenerating Intervertebral Discs from the Same Individual Reveals New Biomarkers for Intervertebral Disc Degeneration. Int J Mol Sci 2022; 23:ijms23073993. [PMID: 35409356 PMCID: PMC8999935 DOI: 10.3390/ijms23073993] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 02/07/2023] Open
Abstract
In this study, we used single-cell transcriptomic analysis to identify new specific biomarkers for nucleus pulposus (NP) and inner annulus fibrosis (iAF) cells, and to define cell populations within non-degenerating (nD) and degenerating (D) human intervertebral discs (IVD) of the same individual. Cluster analysis based on differential gene expression delineated 14 cell clusters. Gene expression profiles at single-cell resolution revealed the potential functional differences linked to degeneration, and among NP and iAF subpopulations. GO and KEGG analyses discovered molecular functions, biological processes, and transcription factors linked to cell type and degeneration state. We propose two lists of biomarkers, one as specific cell type, including C2orf40, MGP, MSMP, CD44, EIF1, LGALS1, RGCC, EPYC, HILPDA, ACAN, MT1F, CHI3L1, ID1, ID3 and TMED2. The second list proposes predictive IVD degeneration genes, including MT1G, SPP1, HMGA1, FN1, FBXO2, SPARC, VIM, CTGF, MGST1, TAF1D, CAPS, SPTSSB, S100A1, CHI3L2, PLA2G2A, TNRSF11B, FGFBP2, MGP, SLPI, DCN, MT-ND2, MTCYB, ADIRF, FRZB, CLEC3A, UPP1, S100A2, PRG4, COL2A1, SOD2 and MT2A. Protein and mRNA expression of MGST1, vimentin, SOD2 and SYF2 (p29) genes validated our scRNA-seq findings. Our data provide new insights into disc cells phenotypes and biomarkers of IVD degeneration that could improve diagnostic and therapeutic options.
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The Cellular Composition of Bovine Coccygeal Intervertebral Discs: A Comprehensive Single-Cell RNAseq Analysis. Int J Mol Sci 2021. [DOI: 10.3390/ijms22094917
expr 996488947 + 961598850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Intervertebral disc (IVD) degeneration and its medical consequences is still one of the leading causes of morbidity worldwide. To support potential regenerative treatments for degenerated IVDs, we sought to deconvolute the cell composition of the nucleus pulposus (NP) and the annulus fibrosus (AF) of bovine intervertebral discs. Bovine calf tails have been extensively used in intervertebral disc research as a readily available source of NP and AF material from healthy and young IVDs. We used single-cell RNA sequencing (scRNAseq) coupled to bulk RNA sequencing (RNAseq) to unravel the cell populations in these two structures and analyze developmental changes across the rostrocaudal axis. By integrating the scRNAseq data with the bulk RNAseq data to stabilize the clustering results of our study, we identified 27 NP structure/tissue specific genes and 24 AF structure/tissue specific genes. From our scRNAseq results, we could deconvolute the heterogeneous cell populations in both the NP and the AF. In the NP, we detected a notochordal-like cell cluster and a progenitor stem cell cluster. In the AF, we detected a stem cell-like cluster, a cluster with a predominantly fibroblast-like phenotype and a potential endothelial progenitor cluster. Taken together, our results illustrate the cell phenotypic complexity of the AF and NP in the young bovine IVDs.
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Calió M, Gantenbein B, Egli M, Poveda L, Ille F. The Cellular Composition of Bovine Coccygeal Intervertebral Discs: A Comprehensive Single-Cell RNAseq Analysis. Int J Mol Sci 2021; 22:ijms22094917. [PMID: 34066404 PMCID: PMC8124861 DOI: 10.3390/ijms22094917] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 02/07/2023] Open
Abstract
Intervertebral disc (IVD) degeneration and its medical consequences is still one of the leading causes of morbidity worldwide. To support potential regenerative treatments for degenerated IVDs, we sought to deconvolute the cell composition of the nucleus pulposus (NP) and the annulus fibrosus (AF) of bovine intervertebral discs. Bovine calf tails have been extensively used in intervertebral disc research as a readily available source of NP and AF material from healthy and young IVDs. We used single-cell RNA sequencing (scRNAseq) coupled to bulk RNA sequencing (RNAseq) to unravel the cell populations in these two structures and analyze developmental changes across the rostrocaudal axis. By integrating the scRNAseq data with the bulk RNAseq data to stabilize the clustering results of our study, we identified 27 NP structure/tissue specific genes and 24 AF structure/tissue specific genes. From our scRNAseq results, we could deconvolute the heterogeneous cell populations in both the NP and the AF. In the NP, we detected a notochordal-like cell cluster and a progenitor stem cell cluster. In the AF, we detected a stem cell-like cluster, a cluster with a predominantly fibroblast-like phenotype and a potential endothelial progenitor cluster. Taken together, our results illustrate the cell phenotypic complexity of the AF and NP in the young bovine IVDs.
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Affiliation(s)
- Martina Calió
- Tissue Engineering for Orthopaedics & Mechanobiology (TOM), Department for BioMedical Research (DBMR), University of Bern, 3008 Bern, Switzerland; (M.C.); (B.G.)
- Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, 3010 Bern, Switzerland
- Space Biology Group, Institute of Medical Engineering, School of Engineering and Architecture, Lucerne University of Applied Sciences and Arts, 6052 Hergiswil, Switzerland;
| | - Benjamin Gantenbein
- Tissue Engineering for Orthopaedics & Mechanobiology (TOM), Department for BioMedical Research (DBMR), University of Bern, 3008 Bern, Switzerland; (M.C.); (B.G.)
- Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, 3010 Bern, Switzerland
| | - Marcel Egli
- Space Biology Group, Institute of Medical Engineering, School of Engineering and Architecture, Lucerne University of Applied Sciences and Arts, 6052 Hergiswil, Switzerland;
| | - Lucy Poveda
- Functional Genomics Center Zurich, Swiss Federal Institute of Technology, University of Zurich, 8057 Zurich, Switzerland;
| | - Fabian Ille
- Space Biology Group, Institute of Medical Engineering, School of Engineering and Architecture, Lucerne University of Applied Sciences and Arts, 6052 Hergiswil, Switzerland;
- Correspondence: ; Tel.: +41-41-349-36-15
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Li K, Varden L, Henderson A, Lufkin T, Kraus P. Simultaneous detection of multiple mRNAs and proteins in bovine IVD cells and tissue with single cell resolution. Biotechnol Lett 2020; 43:13-24. [PMID: 32902710 DOI: 10.1007/s10529-020-02997-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 09/01/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Interactions of cells with their neighbors and influences by the surrounding extracellular matrix (ECM) is reflected in a cells transcriptome and proteome. In tissues comprised of heterogeneous cell populations or cells depending on ECM signalling cues such as those of the intervertebral disc (IVD), this information is obscured or lost when cells are pooled for the commonly used transcript analysis by quantitative PCR or RNA sequencing. Instead, these cells require means to analyse RNA transcript and protein distribution at a single cell or subcellular level to identify different cell types and functions, without removing them from their surrounding signalling cues. RESULTS We developed a simple, sequential protocol combining RNA is situ hybridisation (RISH) and immunohistochemistry (IHC) for the simultaneous analysis of multiple transcripts alongside proteins. This allows one to characterize heterogeneous cell populations at the single cell level in the natural cell environment and signalling context, both in vivo and in vitro. This protocol is demonstrated on cells of the bovine IVD, for transcripts and proteins involved in mechanotransduction, stemness and cell proliferation. CONCLUSIONS A simple, sequential protocol combining RISH and IHC is presented that allows for simultaneous information on RNA transcripts and proteins to characterize cells within a heterogeneous cell population and complex signalling environments such as those of the IVD.
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Affiliation(s)
- Kangning Li
- Department of Biology, Clarkson University, Potsdam, NY, USA
| | - Lara Varden
- Department of Biology, Clarkson University, Potsdam, NY, USA
| | | | - Thomas Lufkin
- Department of Biology, Clarkson University, Potsdam, NY, USA
| | - Petra Kraus
- Department of Biology, Clarkson University, Potsdam, NY, USA.
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Quantitative Single-Cell Transcript Assessment of Biomarkers Supports Cellular Heterogeneity in the Bovine IVD. Vet Sci 2019; 6:vetsci6020042. [PMID: 31083612 PMCID: PMC6631975 DOI: 10.3390/vetsci6020042] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 05/05/2019] [Accepted: 05/09/2019] [Indexed: 02/06/2023] Open
Abstract
Severe and chronic low back pain is often associated with intervertebral disc (IVD) degeneration. While imposing a considerable socio-economic burden worldwide, IVD degeneration is also severely impacting on the quality of life of affected individuals. Cell-based regenerative medicine approaches have moved into clinical trials, yet IVD cell identities in the mature disc remain to be fully elucidated and tissue heterogeneity exists, requiring a better characterization of IVD cells. The bovine coccygeal IVD is an accepted research model to study IVD mechano-biology and disc homeostasis. Recently, we identified novel IVD biomarkers in the outer annulus fibrosus (AF) and nucleus pulposus (NP) of the mature bovine coccygeal IVD through RNA in situ hybridization (AP-RISH) and z-proportion test. Here we follow up on Lam1, Thy1, Gli1, Gli3, Noto, Ptprc, Scx, Sox2 and Zscan10 with fluorescent RNA in situ hybridization (FL-RISH) and confocal microscopy. This permits sub-cellular transcript localization and the addition of quantitative single-cell derived values of mRNA expression levels to our previous analysis. Lastly, we used a Gaussian mixture modeling approach for the exploratory analysis of IVD cells. This work complements our earlier cell population proportion-based study, confirms the previously proposed biomarkers and indicates even further heterogeneity of cells in the outer AF and NP of a mature IVD.
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Kraus P, Sivakamasundari V, Olsen V, Villeneuve V, Hinds A, Lufkin T. Klhl14 Antisense RNA is a Target of Key Skeletogenic Transcription Factors in the Developing Intervertebral Disc. Spine (Phila Pa 1976) 2019; 44:E260-E268. [PMID: 30086079 PMCID: PMC10426336 DOI: 10.1097/brs.0000000000002827] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN RNA in situ hybridization (RISH) allows for validation and characterization of the long noncoding (lnc) natural antisense RNA (NAT) Klhl14as in the embryonic murine intervertebral disc (IVD) in the context of loss-of-function mutants for key transcription factors (TFs) in axial skeleton development. OBJECTIVE Validation of Klhl14as in the developing murine IVD. SUMMARY OF BACKGROUND DATA The IVD is a focus of regenerative medicine; however, processes and signaling cascades resulting in the different cell types in a mature IVD still require clarification in most animals including humans. Technological advances increasingly point to implications of lnc NATs in transcription/translation regulation. Transcriptome data generation and analysis identified a protein encoding transcript and related noncoding antisense transcript as downregulated in embryos devoid of key TFs during axial skeleton development. Here, primarily, the antisense transcript is analyzed in this loss-of-function context. METHODS 4930426D05Rik and 6330403N15Rik were identified as Klhl14as and sense, respectively, two transcripts downregulated in the vertebral column of midgestation Pax1 and Pax9 mutant mouse embryos. RISH on wildtype and mutant embryos for the TF encoding genes Pax1/Pax9, Sox5/Sox6/Sox9, and Bapx1 was used to further analyze Klhl14as in the developing IVD. RESULTS Klhl14as and Klhl14 were the top downregulated transcripts in Pax1; Pax9 E12.5 embryos. Our data demonstrate expression of Klhl14as and sense transcripts in the annulus fibrosus (AF) and notochord of the developing IVD. Klhl14as expression in the inner annulus fibrosus (iAF) seems dependent on the TFs Pax1/Pax9, Sox6, Sox9, and Bapx1. CONCLUSION We are the first to suggest a role for the lncRNA Klhl14as in the developing IVD. Our data link Klhl14as to a previously established gene regulatory network during axial skeleton development and contribute further evidence that lnc NATs are involved in crucial gene regulatory networks in eukaryotic cells. LEVEL OF EVIDENCE N/A.
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Affiliation(s)
- Petra Kraus
- Department of Biology, Clarkson University, Potsdam, NY
| | - V. Sivakamasundari
- Institute for Stem Cell Biology & Regenerative Medicine, Stanford University School of Medicine, Stanford, CA
| | | | | | - Abbey Hinds
- Department of Biology, Clarkson University, Potsdam, NY
| | - Thomas Lufkin
- Department of Biology, Clarkson University, Potsdam, NY
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Li K, Kapper D, Youngs B, Kocsis V, Mondal S, Kraus P, Lufkin T. Potential biomarkers of the mature intervertebral disc identified at the single cell level. J Anat 2018; 234:16-32. [PMID: 30450595 PMCID: PMC6284444 DOI: 10.1111/joa.12904] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2018] [Indexed: 12/17/2022] Open
Abstract
Intervertebral disc (IVD) degeneration and trauma is a major socio-economic burden and the focus of cell-based regenerative medicine approaches. Despite numerous ongoing clinical trials attempting to replace ailing IVD cells with mesenchymal stem cells, a solid understanding of the identity and nature of cells in a healthy mature IVD is still in need of refinement. Although anatomically simple, the IVD is comprised of heterogeneous cell populations. Therefore, methods involving cell pooling for RNA profiling could be misleading. Here, by using RNA in situ hybridization and z proportion test, we have identified potential novel biomarkers through single cell assessment. We quantified the proportion of RNA transcribing cells for 50 genetic loci in the outer annulus fibrosus (AF) and nucleus pulposus (NP) in coccygeal bovine discs isolated from tails of four skeletally mature animals. Our data reconfirm existing data and suggest 10 novel markers such as Lam1 and Thy1 in the outer AF and Gli1, Gli3, Noto, Scx, Ptprc, Sox2, Zscan10 and LOC101904175 in the NP, including pluripotency markers, that indicate stemness potential of IVD cells. These markers could be added to existing biomarker panels for cell type characterization. Furthermore, our data once more demonstrate heterogeneity in cells of the AF and NP, indicating the need for single cell assessment by methods such as RNA in situ hybridization. Our work refines the molecular identity of outer AF and NP cells, which can benefit future regenerative medicine and tissue engineering strategies in humans.
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Affiliation(s)
- Kangning Li
- Department of Biology, Clarkson University, Potsdam, NY, USA
| | - Devin Kapper
- Department of Mathematics, Clarkson University, Potsdam, NY, USA
| | - Brittany Youngs
- Department of Biology, Clarkson University, Potsdam, NY, USA
| | - Victoria Kocsis
- Department of Biology, Clarkson University, Potsdam, NY, USA
| | - Sumona Mondal
- Department of Mathematics, Clarkson University, Potsdam, NY, USA
| | - Petra Kraus
- Department of Biology, Clarkson University, Potsdam, NY, USA
| | - Thomas Lufkin
- Department of Biology, Clarkson University, Potsdam, NY, USA
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